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Gupta D, Burstein AW, Shankar K, Varshney S, Singh O, Osborne-Lawrence S, Richard CP, Zigman JM. Impact of ghrelin on islet size in non-pregnant and pregnant female mice. Endocrinology 2024:bqae048. [PMID: 38626085 DOI: 10.1210/endocr/bqae048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Revised: 04/03/2024] [Accepted: 04/12/2024] [Indexed: 04/18/2024]
Abstract
Reducing ghrelin by ghrelin gene knockout (GKO), ghrelin-cell ablation, or high-fat diet feeding increases islet size and β-cell mass in male mice. Here, we determined if reducing ghrelin also enlarges islets in females, and if pregnancy-associated changes in islet size are related to reduced ghrelin. Islet size and β-cell mass were larger (P=0.057 for β-cell mass) in female GKO mice. Pregnancy was associated with reduced ghrelin and increased LEAP2 [a ghrelin receptor (GHSR) antagonist] in WT mice. Ghrelin deletion and pregnancy each increased islet size (by ∼19.9-30.2% and ∼34.9-46.4%, respectively), percentage of large islets (>25 µm2 x 103, by ∼21.8-42% and ∼21.2-41.2%, respectively) and β-cell mass (by ∼15.7-23.8% and ∼65.2-76.8%, respectively). Neither islet cross-sectional area, β-cell cross-sectional area, nor β-cell mass correlated with plasma ghrelin, although all positively correlated with LEAP2 (P=0.081 for islet cross-sectional area). In ad lib-fed mice, there was an effect of pregnancy, but not ghrelin deletion, to change (raise) plasma insulin without impacting blood glucose. Similarly, there was an effect of pregnancy, but not ghrelin deletion, to change (lower) blood glucose area under the curve during a glucose tolerance test. Thus, genetic deletion of ghrelin increases islet size and β-cell cross-sectional area in female mice, similar to males. Yet, despite pregnancy-associated reductions in ghrelin, other factors appear to govern islet enlargement and changes to insulin sensitivity and glucose tolerance in the setting of pregnancy. In the case of islet size and β-cell mass, one of those factors may be the pregnancy-associated increase in LEAP2.
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Affiliation(s)
- Deepali Gupta
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas Texas, USA
| | - Avi W Burstein
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas Texas, USA
| | - Kripa Shankar
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas Texas, USA
| | - Salil Varshney
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas Texas, USA
| | - Omprakash Singh
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas Texas, USA
| | - Sherri Osborne-Lawrence
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas Texas, USA
| | - Corine P Richard
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas Texas, USA
| | - Jeffrey M Zigman
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas Texas, USA
- Division of Endocrinology & Metabolism, Department of Internal Medicine, UT Southwestern Medical Center, Dallas Texas, USA
- Department of Psychiatry, UT Southwestern Medical Center, Dallas Texas, USA
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Nie M, Zhang J, Bal M, Duran C, An SW, Zigman JM, Baum M, Hiremath C, Marciano DK, Wolf MTF. Ghrelin enhances tubular magnesium absorption in the kidney. Front Physiol 2024; 15:1363708. [PMID: 38638279 PMCID: PMC11024433 DOI: 10.3389/fphys.2024.1363708] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2023] [Accepted: 03/07/2024] [Indexed: 04/20/2024] Open
Abstract
Osteoporosis after bariatric surgery is an increasing health concern as the rate of bariatric surgery has risen. In animal studies mimicking bariatric procedures, bone disease, together with decreased serum levels of Ca2+, Mg2+ and the gastric hormone Ghrelin were described. Ghrelin regulates metabolism by binding to and activating the growth hormone secretagogue receptor (GHSR) which is also expressed in the kidney. As calcium and magnesium are key components of bone, we tested the hypothesis that Ghrelin-deficiency contributes to osteoporosis via reduced upregulation of the renal calcium channel TRPV5 and the heteromeric magnesium channel TRPM6/7. We expressed GHSR with TRPV5 or TRPM6/7 channel in HEK293 cells and treated them with purified Ghrelin. Whole-cell current density was analyzed by patch-clamp recording. Nephron-specific gene expression was performed by tubular microdissection followed by qPCR in wild-type (WT) mice, and immunofluorescent imaging of GHSR-eGFP mice. Tubular magnesium homeostasis was analyzed in GHSR-null and WT mice at baseline and after caloric restriction. After Ghrelin exposure, whole-cell current density did not change for TRPV5 but increased for TRPM6/7 in a dose-dependent fashion. Applying the Ghrelin-mimetic (D-Trp7, Ala8,D-Phe10)-α-MSH (6-11) amide without and with the GHSR antagonist (D-Lys3)-GHRP6, we confirmed the stimulatory role of Ghrelin towards TRPM6/7. As GHSR initiates downstream signaling via protein kinase A (PKA), we found that the PKA inhibitor H89 abrogated TRPM6/7 stimulation by Ghrelin. Similarly, transfected Gαs, but not the Gαs mutant Q227L, nor Gαi2, Gαq, or Gα13 upregulated TRPM6/7 current density. In microdissected TALs and DCTs similar levels of GHSR mRNA were detected. In contrast, TRPM6 mRNA was expressed in the DCT and also detected in the TAL at 25% expression compared to DCT. Immunofluorescent studies using reporter GHSR-eGFP mice showed a strong eGFP signal in the TAL but surprisingly displayed no eGFP signal in the DCT. In 3-, 6-, and 9-month-old GHSR-null and WT mice, baseline serum magnesium was not significantly different, but 24-h urinary magnesium excretion was elevated in 9-month-old GHSR-null mice. In calorically restricted GHSR-null mice, we detected excess urinary magnesium excretion and reduced serum magnesium levels compared to WT mice. The kidneys from calorically restricted WT mice showed upregulated gene expression of magnesiotropic genes Hnf1b, Cldn-16, Cldn-19, Fxyd-2b, and Parvalbumin compared to GHSR-null mice. Our in vitro studies show that Ghrelin stimulates TRPM6/7 via GHSR and Gαs-PKA signaling. The murine studies are consistent with Ghrelin-GHSR signaling inducing reduced urinary magnesium excretion, particularly in calorically restricted mice when Ghrelin levels are elevated. This effect may be mediated by Ghrelin-upregulation of TRPM6 in the TAL and/or upregulation of other magnesiotropic genes. We postulate that rising Ghrelin levels with hunger contribute to increased renal Mg2+ reabsorption to compensate for lack of enteral Mg2+ uptake.
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Affiliation(s)
- Mingzhu Nie
- Pediatric Nephrology, Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Jing Zhang
- Pediatric Nephrology, Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Manjot Bal
- Pediatric Nephrology, Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Claudia Duran
- Pediatric Nephrology, Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Sung Wan An
- Pediatric Nephrology, Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, United States
- Pediatric Nephrology, Department of Pediatrics, University of Michigan, Ann Arbor, MI, United States
| | - Jeffrey M. Zigman
- Department of Internal Medicine, Center for Hypothalamic Research, UTSW Medical Center, Dallas, TX, United States
| | - Michel Baum
- Pediatric Nephrology, Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Chitkale Hiremath
- Department of Internal Medicine, Nephrology, and Department of Cell Biology, UTSW Medical Center, Dallas, TX, United States
| | - Denise K. Marciano
- Department of Internal Medicine, Nephrology, and Department of Cell Biology, UTSW Medical Center, Dallas, TX, United States
| | - Matthias T. F. Wolf
- Pediatric Nephrology, Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, United States
- Pediatric Nephrology, Department of Pediatrics, University of Michigan, Ann Arbor, MI, United States
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Kulkarni SS, Singh O, Zigman JM. The intersection between ghrelin, metabolism and circadian rhythms. Nat Rev Endocrinol 2024; 20:228-238. [PMID: 38123819 DOI: 10.1038/s41574-023-00927-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/16/2023] [Indexed: 12/23/2023]
Abstract
Despite the growing popular interest in sleep and diet, many gaps exist in our scientific understanding of the interaction between circadian rhythms and metabolism. In this Review, we explore a promising, bidirectional role for ghrelin in mediating this interaction. Ghrelin both influences and is influenced by central and peripheral circadian systems. Specifically, we focus on how ghrelin impacts outputs of circadian rhythm, including neuronal activity, circulating growth hormone levels, locomotor activity and eating behaviour. We also consider the effects of circadian rhythms on ghrelin expression and the consequences of disrupted circadian patterns, such as shift work and jet lag, on ghrelin secretion. Our Review is aimed at both the casual reader interested in gaining more insight into the scientific context surrounding the trending topics of sleep and metabolism, as well as experienced scientists in the fields of ghrelin and circadian biology seeking inspiration and a comprehensive overview of how these fields are related.
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Affiliation(s)
- Soumya S Kulkarni
- Medical Scientist Training Program, UT Southwestern Medical Center, Dallas, TX, USA
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, USA
| | - Omprakash Singh
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, USA
| | - Jeffrey M Zigman
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, USA.
- Division of Endocrinology, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, USA.
- Department of Psychiatry, UT Southwestern Medical Center, Dallas, TX, USA.
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Howe SL, Holdom CJ, McCombe PA, Henderson RD, Zigman JM, Ngo ST, Steyn FJ. Associations of postprandial ghrelin, liver-expressed antimicrobial peptide 2 and leptin levels with body composition, disease progression and survival in patients with amyotrophic lateral sclerosis. Eur J Neurol 2024; 31:e16052. [PMID: 37658515 PMCID: PMC10840749 DOI: 10.1111/ene.16052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2023] [Revised: 08/06/2023] [Accepted: 08/17/2023] [Indexed: 09/03/2023]
Abstract
BACKGROUND AND PURPOSE Loss of appetite contributes to weight loss and faster disease progression in amyotrophic lateral sclerosis (ALS). Impairment of appetite control in ALS may include altered production or action of orexigenic (i.e., ghrelin) and anorexigenic (i.e., liver-expressed antimicrobial peptide 2 [LEAP2] and leptin) hormones. We aimed to determine if postprandial circulating ghrelin levels, LEAP2 levels, LEAP2:ghrelin molar ratio and leptin levels differ in ALS patients compared to non-neurodegenerative disease controls, and whether they are associated with disease progression and body composition. METHODS In this prospective natural history study, we assessed postprandial plasma levels of ghrelin, LEAP2 and leptin in patients with ALS (cases; n = 46) and controls (controls; n = 43). For cases, measures were compared to changes in body weight, body composition and clinical outcomes. RESULTS Postprandial ghrelin level was decreased by 52% in cases compared to controls (p = 0.013). LEAP2:ghrelin molar ratio was increased by 249% (p = 0.009), suggesting greater ghrelin resistance. Patients with lower LEAP2:ghrelin tended to have better functional capacity at assessment, as inferred by the ALS Functional Rating Scale-Revised (τ = -0.179, p = 0.086). Furthermore, ghrelin and LEAP2:ghrelin molar ratio correlated with diagnostic delay (ghrelin, τ = 0.223, p = 0.029; LEAP2:ghrelin, τ = -0.213, p = 0.037). Baseline ghrelin level, LEAP2 level, LEAP2:ghrelin ratio and leptin level were, however, not predictive of change in functional capacity during follow-up. Also, patients with higher postprandial ghrelin levels (hazard ratio [HR] 1.375, p = 0.048), and lower LEAP2:ghelin ratios (HR 0.828, p = 0.051) had an increased risk of earlier death. CONCLUSIONS Reduced postprandial ghrelin levels, coupled with increased LEAP2:ghrelin molar ratios, suggests a loss of ghrelin action in patients with ALS. Given ghrelin's actions on appetite, metabolism and neuroprotection, reduced ghrelin and greater ghrelin resistance could contribute to impaired capacity to tolerate the physiological impact of disease. Comprehensive studies are needed to explain how ghrelin and LEAP2 contribute to body weight regulation and disease progression in ALS.
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Affiliation(s)
- Stephanie L Howe
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, Queensland, Australia
| | - Cory J Holdom
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, Queensland, Australia
- Centre for Clinical Research, The University of Queensland, Brisbane, Queensland, Australia
| | - Pamela A McCombe
- Centre for Clinical Research, The University of Queensland, Brisbane, Queensland, Australia
- Department of Neurology, Royal Brisbane and Women's Hospital, Brisbane, Queensland, Australia
| | - Robert D Henderson
- Centre for Clinical Research, The University of Queensland, Brisbane, Queensland, Australia
- Department of Neurology, Royal Brisbane and Women's Hospital, Brisbane, Queensland, Australia
| | - Jeffrey M Zigman
- Center for Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Shyuan T Ngo
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane, Queensland, Australia
- Centre for Clinical Research, The University of Queensland, Brisbane, Queensland, Australia
- Department of Neurology, Royal Brisbane and Women's Hospital, Brisbane, Queensland, Australia
| | - Frederik J Steyn
- Department of Neurology, Royal Brisbane and Women's Hospital, Brisbane, Queensland, Australia
- School of Biomedical Sciences, The University of Queensland, Brisbane, Queensland, Australia
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Singh O, Ogden SB, Varshney S, Shankar K, Gupta D, Paul S, Osborne-Lawrence S, Richard CP, Metzger NP, Lawrence C, Leon Mercado L, Zigman JM. Ghrelin-responsive mediobasal hypothalamic neurons mediate exercise-associated food intake and exercise endurance. JCI Insight 2023; 8:e172549. [PMID: 37962950 PMCID: PMC10807726 DOI: 10.1172/jci.insight.172549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Accepted: 11/08/2023] [Indexed: 11/16/2023] Open
Abstract
Previous studies have implicated the orexigenic hormone ghrelin as a mediator of exercise endurance and the feeding response postexercise. Specifically, plasma ghrelin levels nearly double in mice when they are subjected to an hour-long bout of high-intensity interval exercise (HIIE) using treadmills. Also, growth hormone secretagogue receptor-null (GHSR-null) mice exhibit decreased food intake following HIIE and diminished running distance (time until exhaustion) during a longer, stepwise exercise endurance protocol. To investigate whether ghrelin-responsive mediobasal hypothalamus (MBH) neurons mediate these effects, we stereotaxically delivered the inhibitory designer receptor exclusively activated by designer drugs virus AAV2-hSyn-DIO-hM4(Gi)-mCherry to the MBH of Ghsr-IRES-Cre mice, which express Cre recombinase directed by the Ghsr promoter. We found that chemogenetic inhibition of GHSR-expressing MBH neurons (upon delivery of clozapine-N-oxide) 1) suppressed food intake following HIIE, 2) reduced maximum running distance and raised blood glucose and blood lactate levels during an exercise endurance protocol, 3) reduced food intake following ghrelin administration, and 4) did not affect glucose tolerance. Further, HIIE increased MBH Ghsr expression. These results indicate that activation of ghrelin-responsive MBH neurons is required for the normal feeding response to HIIE and the usual amount of running exhibited during an exercise endurance protocol.
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Affiliation(s)
- Omprakash Singh
- Center for Hypothalamic Research, Department of Internal Medicine
| | - Sean B. Ogden
- Center for Hypothalamic Research, Department of Internal Medicine
| | - Salil Varshney
- Center for Hypothalamic Research, Department of Internal Medicine
| | - Kripa Shankar
- Center for Hypothalamic Research, Department of Internal Medicine
| | - Deepali Gupta
- Center for Hypothalamic Research, Department of Internal Medicine
| | - Subhojit Paul
- Center for Hypothalamic Research, Department of Internal Medicine
| | | | | | | | - Connor Lawrence
- Center for Hypothalamic Research, Department of Internal Medicine
| | | | - Jeffrey M. Zigman
- Center for Hypothalamic Research, Department of Internal Medicine
- Division of Endocrinology & Metabolism, Department of Internal Medicine; and
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, Texas, USA
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6
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Gupta D, Burstein AW, Schwalbe DC, Shankar K, Varshney S, Singh O, Paul S, Ogden SB, Osborne-Lawrence S, Metzger NP, Richard CP, Campbell JN, Zigman JM. Ghrelin deletion and conditional ghrelin cell ablation increase pancreatic islet size in mice. J Clin Invest 2023; 133:e169349. [PMID: 38099492 PMCID: PMC10721155 DOI: 10.1172/jci169349] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Accepted: 10/05/2023] [Indexed: 12/18/2023] Open
Abstract
Ghrelin exerts key effects on islet hormone secretion to regulate blood glucose levels. Here, we sought to determine whether ghrelin's effects on islets extend to the alteration of islet size and β cell mass. We demonstrate that reducing ghrelin - by ghrelin gene knockout (GKO), conditional ghrelin cell ablation, or high-fat diet (HFD) feeding - was associated with increased mean islet size (up to 62%), percentage of large islets (up to 854%), and β cell cross-sectional area (up to 51%). In GKO mice, these effects were more apparent in 10- to 12-week-old mice than in 4-week-old mice. Higher β cell numbers from decreased β cell apoptosis drove the increase in β cell cross-sectional area. Conditional ghrelin cell ablation in adult mice increased the β cell number per islet by 40% within 4 weeks. A negative correlation between islet size and plasma ghrelin in HFD-fed plus chow-fed WT mice, together with even larger islet sizes in HFD-fed GKO mice than in HFD-fed WT mice, suggests that reduced ghrelin was not solely responsible for diet-induced obesity-associated islet enlargement. Single-cell transcriptomics revealed changes in gene expression in several GKO islet cell types, including upregulation of Manf, Dnajc3, and Gnas expression in β cells, which supports decreased β cell apoptosis and/or increased β cell proliferation. These effects of ghrelin reduction on islet morphology might prove useful when designing new therapies for diabetes.
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Affiliation(s)
- Deepali Gupta
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Avi W. Burstein
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Dana C. Schwalbe
- Department of Biology, University of Virginia, Charlottesville, Virginia, USA
| | - Kripa Shankar
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Salil Varshney
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Omprakash Singh
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Subhojit Paul
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Sean B. Ogden
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Sherri Osborne-Lawrence
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Nathan P. Metzger
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Corine P. Richard
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas, USA
| | - John N. Campbell
- Department of Biology, University of Virginia, Charlottesville, Virginia, USA
| | - Jeffrey M. Zigman
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas, USA
- Division of Endocrinology and Metabolism, Department of Internal Medicine and
- Department of Psychiatry, UT Southwestern Medical Center, Dallas, Texas, USA
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So WL, Hu J, Jeffs L, Dempsey H, Lockie SH, Zigman JM, Stark R, Reichenbach A, Andrews ZB. Ghrelin signalling in AgRP neurons links metabolic state to the sensory regulation of AgRP neural activity. Mol Metab 2023; 78:101826. [PMID: 37898450 PMCID: PMC10643323 DOI: 10.1016/j.molmet.2023.101826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 10/11/2023] [Accepted: 10/13/2023] [Indexed: 10/30/2023] Open
Abstract
OBJECTIVE The sensory detection of food and food cues suppresses Agouti related peptide (AgRP) neuronal activity prior to consumption with greatest suppression occurring in response to highly caloric food or interoceptive energy need. However, the interoceptive mechanisms priming an appropriate AgRP neural response to external sensory information of food availability remain unexplored. Since hunger increases plasma ghrelin, we hypothesized that ghrelin receptor (GHSR) signalling on AgRP neurons is a key interoceptive mechanism integrating energy need with external sensory cues predicting caloric availability. METHODS We used in vivo photometry to measure the effects of ghrelin administration or fasting on AgRP neural activity with GCaMP6s and dopamine release in the nucleus accumbens with GRAB-DA in mice lacking ghrelin receptors in AgRP neurons. RESULTS The deletion of GHSR on AgRP neurons prevented ghrelin-induced food intake, motivation and AgRP activity. The presentation of food (peanut butter pellet) or a wooden dowel suppressed AgRP activity in fasted WT but not mice lacking GHSRs in AgRP neurons. Similarly, peanut butter and a wooden dowel increased dopamine release in the nucleus accumbens after ip ghrelin injection in WT but not mice lacking GHSRs in AgRP neurons. No difference in dopamine release was observed in fasted mice. Finally, ip ghrelin administration did not directly increase dopamine neural activity in the ventral tegmental area. CONCLUSIONS Our results suggest that AgRP GHSRs integrate an interoceptive state of energy need with external sensory information to produce an optimal change in AgRP neural activity. Thus, ghrelin signalling on AgRP neurons is more than just a feedback signal to increase AgRP activity during hunger.
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Affiliation(s)
- Wang Lok So
- Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton 3800, Victoria, Australia
| | - Jiachen Hu
- Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton 3800, Victoria, Australia
| | - Lotus Jeffs
- Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton 3800, Victoria, Australia
| | - Harry Dempsey
- The Florey Institute of Neuroscience and Mental Health, Mental Health Division, Parkville, Melbourne, Australia
| | - Sarah H Lockie
- Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton 3800, Victoria, Australia
| | - Jeffrey M Zigman
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, USA; Division of Endocrinology, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, USA; Department of Psychiatry, UT Southwestern Medical Center, Dallas, TX, USA
| | - Romana Stark
- Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton 3800, Victoria, Australia
| | - Alex Reichenbach
- Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton 3800, Victoria, Australia
| | - Zane B Andrews
- Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton 3800, Victoria, Australia.
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Alex Thomas M, Cui X, Artinian LR, Cao Q, Jing J, Silva FC, Wang S, Zigman JM, Sun Y, Shi H, Xue B. Crosstalk between Gut Sensory Ghrelin Signaling and Adipose Tissue Sympathetic Outflow Regulates Metabolic Homeostasis. bioRxiv 2023:2023.11.25.568689. [PMID: 38076894 PMCID: PMC10705268 DOI: 10.1101/2023.11.25.568689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/23/2023]
Abstract
The stomach-derived orexigenic hormone ghrelin is a key regulator of energy homeostasis and metabolism in humans. The ghrelin receptor, growth hormone secretagogue receptor 1a (GHSR), is widely expressed in the brain and gastrointestinal vagal sensory neurons, and neuronal GHSR knockout results in a profoundly beneficial metabolic profile and protects against diet-induced obesity (DIO) and insulin resistance. Here we show that in addition to the well characterized vagal GHSR, GHSR is robustly expressed in gastrointestinal sensory neurons emanating from spinal dorsal root ganglia. Remarkably, sensory neuron GHSR deletion attenuates DIO through increased energy expenditure and sympathetic outflow to adipose tissue independent of food intake. In addition, neuronal viral tract tracing reveals prominent crosstalk between gut non-vagal sensory afferents and adipose sympathetic outflow. Hence, these findings demonstrate a novel gut sensory ghrelin signaling pathway critical for maintaining energy homeostasis.
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Affiliation(s)
- M. Alex Thomas
- Department of Biology, Georgia State University, Atlanta, GA
| | - Xin Cui
- Department of Biology, Georgia State University, Atlanta, GA
| | | | - Qiang Cao
- Department of Biology, Georgia State University, Atlanta, GA
| | - Jia Jing
- Department of Biology, Georgia State University, Atlanta, GA
| | - Felipe C. Silva
- Department of Biology, Georgia State University, Atlanta, GA
| | - Shirong Wang
- Department of Biology, Georgia State University, Atlanta, GA
| | - Jeffrey M. Zigman
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX
| | - Yuxiang Sun
- Department of Nutrition, Texas A & M University, College Station, TX
| | - Hang Shi
- Department of Biology, Georgia State University, Atlanta, GA
| | - Bingzhong Xue
- Department of Biology, Georgia State University, Atlanta, GA
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9
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Barrile F, Cassano D, Fernandez G, De Francesco PN, Reynaldo M, Cantel S, Fehrentz JA, Donato J, Schiöth HB, Zigman JM, Perello M. Ghrelin's orexigenic action in the lateral hypothalamic area involves indirect recruitment of orexin neurons and arcuate nucleus activation. Psychoneuroendocrinology 2023; 156:106333. [PMID: 37454647 PMCID: PMC10530520 DOI: 10.1016/j.psyneuen.2023.106333] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Revised: 05/30/2023] [Accepted: 07/10/2023] [Indexed: 07/18/2023]
Abstract
OBJECTIVE Ghrelin is a potent orexigenic hormone, and the lateral hypothalamic area (LHA) has been suggested as a putative target mediating ghrelin's effects on food intake. Here, we aimed to investigate the presence of neurons expressing ghrelin receptor (a.k.a. growth hormone secretagogue receptor, GHSR) in the mouse LHA (LHAGHSR neurons), its physiological implications and the neuronal circuit recruited by local ghrelin action. METHODS We investigated the distribution of LHAGHSR neurons using different histologic strategies, including the use of a reporter mice expressing enhanced green fluorescent protein under the control of the GHSR promoter. Also, we investigated the physiological implications of local injections of ghrelin within the LHA, and the extent to which the orexigenic effect of intra-LHA-injected ghrelin involves the arcuate nucleus (ARH) and orexin neurons of the LHA (LHAorexin neurons) RESULTS: We found that: 1) LHAGHSR neurons are homogeneously distributed throughout the entire LHA; 2) intra-LHA injections of ghrelin transiently increase food intake and locomotor activity; 3) ghrelin's orexigenic effect in the LHA involves the indirect recruitment of LHAorexin neurons and the activation of ARH neurons; and 4) LHAGHSR neurons are not targeted by plasma ghrelin. CONCLUSIONS We provide a compelling neuroanatomical and functional characterization of LHAGHSR neurons in male mice that indicates that LHAGHSR cells are part of a hypothalamic neuronal circuit that potently induces food intake.
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Affiliation(s)
- Franco Barrile
- Laboratory of Neurophysiology of the Multidisciplinary Institute of Cell Biology [IMBICE, Argentine Research Council (CONICET) and Scientific Research Commission, Province of Buenos Aires (CIC-PBA), National University of La Plata], La Plata, Buenos Aires, Argentina
| | - Daniela Cassano
- Laboratory of Neurophysiology of the Multidisciplinary Institute of Cell Biology [IMBICE, Argentine Research Council (CONICET) and Scientific Research Commission, Province of Buenos Aires (CIC-PBA), National University of La Plata], La Plata, Buenos Aires, Argentina
| | - Gimena Fernandez
- Laboratory of Neurophysiology of the Multidisciplinary Institute of Cell Biology [IMBICE, Argentine Research Council (CONICET) and Scientific Research Commission, Province of Buenos Aires (CIC-PBA), National University of La Plata], La Plata, Buenos Aires, Argentina
| | - Pablo N De Francesco
- Laboratory of Neurophysiology of the Multidisciplinary Institute of Cell Biology [IMBICE, Argentine Research Council (CONICET) and Scientific Research Commission, Province of Buenos Aires (CIC-PBA), National University of La Plata], La Plata, Buenos Aires, Argentina
| | - Mirta Reynaldo
- Laboratory of Neurophysiology of the Multidisciplinary Institute of Cell Biology [IMBICE, Argentine Research Council (CONICET) and Scientific Research Commission, Province of Buenos Aires (CIC-PBA), National University of La Plata], La Plata, Buenos Aires, Argentina
| | - Sonia Cantel
- Institut des Biomolécules Max Mousseron, Univ Montpellier, CNRS, ENSCM, Montpellier, France
| | - Jean-Alain Fehrentz
- Institut des Biomolécules Max Mousseron, Univ Montpellier, CNRS, ENSCM, Montpellier, France
| | - José Donato
- Department of Physiology and Biophysics, Instituto de Ciencias Biomedicas, Universidade de São Paulo, São Paulo, Brazil
| | - Helgi B Schiöth
- Department of Surgical Sciences, Functional Pharmacology and Neuroscience, University of Uppsala, Uppsala, Sweden
| | - Jeffrey M Zigman
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, USA
| | - Mario Perello
- Laboratory of Neurophysiology of the Multidisciplinary Institute of Cell Biology [IMBICE, Argentine Research Council (CONICET) and Scientific Research Commission, Province of Buenos Aires (CIC-PBA), National University of La Plata], La Plata, Buenos Aires, Argentina; Department of Surgical Sciences, Functional Pharmacology and Neuroscience, University of Uppsala, Uppsala, Sweden.
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10
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Shankar K, Varshney S, Gupta D, Mani BK, Osborne-Lawrence S, Metzger NP, Richard CP, Zigman JM. Ghrelin does not impact the blunted counterregulatory response to recurrent hypoglycemia in mice. Front Endocrinol (Lausanne) 2023; 14:1181856. [PMID: 37334290 PMCID: PMC10272800 DOI: 10.3389/fendo.2023.1181856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Accepted: 05/23/2023] [Indexed: 06/20/2023] Open
Abstract
Introduction Recurrent episodes of insulin-induced hypoglycemia in patients with diabetes mellitus can result in hypoglycemia-associated autonomic failure (HAAF), which is characterized by a compromised response to hypoglycemia by counterregulatory hormones (counterregulatory response; CRR) and hypoglycemia unawareness. HAAF is a leading cause of morbidity in diabetes and often hinders optimal regulation of blood glucose levels. Yet, the molecular pathways underlying HAAF remain incompletely described. We previously reported that in mice, ghrelin is permissive for the usual CRR to insulin-induced hypoglycemia. Here, we tested the hypothesis that attenuated release of ghrelin both results from HAAF and contributes to HAAF. Methods C57BL/6N mice, ghrelin-knockout (KO) + control mice, and GhIRKO (ghrelin cell-selective insulin receptor knockout) + control mice were randomized to one of three treatment groups: a "Euglycemia" group was injected with saline and remained euglycemic; a 1X hypoglycemia ("1X Hypo") group underwent a single episode of insulin-induced hypoglycemia; a recurrent hypoglycemia ("Recurrent Hypo") group underwent repeated episodes of insulin-induced hypoglycemia over five successive days. Results Recurrent hypoglycemia exaggerated the reduction in blood glucose (by ~30%) and attenuated the elevations in plasma levels of the CRR hormones glucagon (by 64.5%) and epinephrine (by 52.9%) in C57BL/6N mice compared to a single hypoglycemic episode. Yet, plasma ghrelin was equivalently reduced in "1X Hypo" and "Recurrent Hypo" C57BL/6N mice. Ghrelin-KO mice exhibited neither exaggerated hypoglycemia in response to recurrent hypoglycemia, nor any additional attenuation in CRR hormone levels compared to wild-type littermates. Also, in response to recurrent hypoglycemia, GhIRKO mice exhibited nearly identical blood glucose and plasma CRR hormone levels as littermates with intact insulin receptor expression (floxed-IR mice), despite higher plasma ghrelin in GhIRKO mice. Conclusions These data suggest that the usual reduction of plasma ghrelin due to insulin-induced hypoglycemia is unaltered by recurrent hypoglycemia and that ghrelin does not impact blood glucose or the blunted CRR hormone responses during recurrent hypoglycemia.
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Affiliation(s)
- Kripa Shankar
- Center for Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Salil Varshney
- Center for Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Deepali Gupta
- Center for Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Bharath K. Mani
- Center for Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Sherri Osborne-Lawrence
- Center for Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Nathan P. Metzger
- Center for Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Corine P. Richard
- Center for Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Jeffrey M. Zigman
- Center for Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, United States
- Division of Endocrinology, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, United States
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX, United States
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11
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Tian J, Guo L, Wang T, Jia K, Swerdlow RH, Zigman JM, Du H. Liver-expressed antimicrobial peptide 2 elevation contributes to age-associated cognitive decline. JCI Insight 2023; 8:166175. [PMID: 37212281 DOI: 10.1172/jci.insight.166175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Accepted: 03/31/2023] [Indexed: 05/23/2023] Open
Abstract
Elderly individuals frequently report cognitive decline, while various studies indicate hippocampal functional declines with advancing age. Hippocampal function is influenced by ghrelin through hippocampus-expressed growth hormone secretagogue receptor (GHSR). Liver-expressed antimicrobial peptide 2 (LEAP2) is an endogenous GHSR antagonist that attenuates ghrelin signaling. Here, we measured plasma ghrelin and LEAP2 levels in a cohort of cognitively normal individuals older than 60 and found that LEAP2 increased with age while ghrelin (also referred to in literature as "acyl-ghrelin") marginally declined. In this cohort, plasma LEAP2/ghrelin molar ratios were inversely associated with Mini-Mental State Examination scores. Studies in mice showed an age-dependent inverse relationship between plasma LEAP2/ghrelin molar ratio and hippocampal lesions. In aged mice, restoration of the LEAP2/ghrelin balance to youth-associated levels with lentiviral shRNA Leap2 downregulation improved cognitive performance and mitigated various age-related hippocampal deficiencies such as CA1 region synaptic loss, declines in neurogenesis, and neuroinflammation. Our data collectively suggest that LEAP2/ghrelin molar ratio elevation may adversely affect hippocampal function and, consequently, cognitive performance; thus, it may serve as a biomarker of age-related cognitive decline. Moreover, targeting LEAP2 and ghrelin in a manner that lowers the plasma LEAP2/ghrelin molar ratio could benefit cognitive performance in elderly individuals for rejuvenation of memory.
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Affiliation(s)
- Jing Tian
- Department of Pharmacology and Toxicology and
| | - Lan Guo
- Higuchi Biosciences Center, University of Kansas, Lawrence, Kansas, USA
| | - Tienju Wang
- Department of Pharmacology and Toxicology and
| | - Kun Jia
- Department of Pharmacology and Toxicology and
| | - Russell H Swerdlow
- Alzheimer's Disease Center, University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Jeffrey M Zigman
- Departments of Internal Medicine and Psychiatry, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Heng Du
- Department of Pharmacology and Toxicology and
- Higuchi Biosciences Center, University of Kansas, Lawrence, Kansas, USA
- Alzheimer's Disease Center, University of Kansas Medical Center, Kansas City, Kansas, USA
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12
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Osborne-Lawrence S, Lawrence C, Metzger NP, Klavon J, Baig HR, Richard C, Varshney S, Gupta D, Singh O, Ogden SB, Shankar K, Paul S, Butler RK, Zigman JM. Effects of thermoneutrality on food intake, body weight, and body composition in a Prader-Willi syndrome mouse model. Obesity (Silver Spring) 2023; 31:1644-1654. [PMID: 37161883 DOI: 10.1002/oby.23766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Revised: 01/28/2023] [Accepted: 02/28/2023] [Indexed: 05/11/2023]
Abstract
OBJECTIVE Prader-Willi syndrome (PWS) is a multisystem genetic disorder. Unfortunately, none of several mouse models carrying PWS mutations emulates the entirety of the human PWS phenotype, including hyperphagia plus obesity. METHODS To determine whether housing at thermoneutrality (TN, 30 °C) permits the development of hyperphagia and obesity in the Snord116del PWS mouse model, the effects of housing three different ages of Snord116del and wild-type (WT) littermates at TN versus room temperature (RT, 22-24 °C) for 8 weeks were compared. RESULTS Snord116del mice born and maintained at TN exhibited lower body weight curves, lower percentage fat mass, and lower food intake than WT mice at RT. In 4- to 6-month-old high-fat diet-fed female mice, TN raised the Snord116del body weight curve closer to that of RT-housed WT mice although the TN-housed Snord116del mice did not gain more adiposity or exhibit greater food intake. In 6- to 8-month-old high-fat diet-fed male mice, body weight, adiposity, and food intake of TN-housed Snord116del mice remained far below levels in RT-housed WT mice. TN elicited hypotonia in Snord116del adults and exacerbated mortality of Snord116del newborns. CONCLUSIONS In none of three tested TN protocols were greater food intake, body weight, or adiposity induced in Snord116del mice compared with RT-housed WT mice.
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Affiliation(s)
- Sherri Osborne-Lawrence
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Connor Lawrence
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Nathan P Metzger
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Julia Klavon
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Hassan R Baig
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Corine Richard
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Salil Varshney
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Deepali Gupta
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Omprakash Singh
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Sean B Ogden
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Kripa Shankar
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Subhojit Paul
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Ryan K Butler
- Department of Psychiatry, UT Southwestern Medical Center, Dallas, Texas, USA
- O'Donnell Brain Institute, UT Southwestern Medical Center, Dallas, Texas, USA
- Department of Pediatrics, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Jeffrey M Zigman
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas, USA
- Department of Psychiatry, UT Southwestern Medical Center, Dallas, Texas, USA
- O'Donnell Brain Institute, UT Southwestern Medical Center, Dallas, Texas, USA
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13
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Tian J, Du E, Jia K, Wang T, Guo L, Zigman JM, Du H. Elevated Ghrelin Promotes Hippocampal Ghrelin Receptor Defects in Humanized Amyloid-β Knockin Mice During Aging. J Alzheimers Dis 2023; 96:1579-1592. [PMID: 38007666 PMCID: PMC10841720 DOI: 10.3233/jad-231002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2023]
Abstract
BACKGROUND Emerging evidence has revealed that dysregulation of the hormone ghrelin and its receptor, growth hormone secretagogue receptor (GHSR), contributes to the pathogenesis of Alzheimer's disease (AD). Specifically, defective GHSR function and resultant hippocampal ghrelin resistance are linked to hippocampal synaptic injury in AD paradigms. Also, AD patients exhibit elevated ghrelin activation. However, the detailed molecular mechanisms of hippocampal GHSR dysfunction and the relevance of ghrelin elevation to hippocampal ghrelin resistance in AD-relevant pathological settings are not fully understood. OBJECTIVE In the current study, we employed a recently established mouse line of AD risk [humanized amyloid beta knockin (hAβ KI mice), also referred to as a mouse model of late-onset AD in previous literature] to further define the role of ghrelin system dysregulation in the development of AD. METHODS We employed multidisciplinary techniques to determine the change of plasma ghrelin and the functional status of GHSR in hAβ KI mice as well as primary neuron cultures. RESULTS We observed concurrent plasma ghrelin elevation and hippocampal GHSR desensitization with disease progression. Further examination excluded the possibility that ghrelin elevation is a compensatory change in response to GHSR dysfunction. In contrast, further in vitro and in vivo results show that agonist-mediated overstimulation potentiates GHSR desensitization through enhanced GHSR internalization. CONCLUSIONS These findings suggest that circulating ghrelin elevation is a pathological event underlying hippocampal GHSR dysfunction, culminating in hippocampal ghrelin resistance and resultant synaptic injury in late-onset AD-related settings.
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Affiliation(s)
- Jing Tian
- Department of Pharmacology and Toxicology, The University of Kansas, Lawrence, KS, USA
| | - Eric Du
- Department of Pharmacology and Toxicology, The University of Kansas, Lawrence, KS, USA
- Blue Valley West High School, Overland Park, KS, USA
| | - Kun Jia
- Department of Pharmacology and Toxicology, The University of Kansas, Lawrence, KS, USA
| | - Tienju Wang
- Department of Pharmacology and Toxicology, The University of Kansas, Lawrence, KS, USA
| | - Lan Guo
- Department of Pharmacology and Toxicology, The University of Kansas, Lawrence, KS, USA
| | - Jeffrey M. Zigman
- Department of Internal Medicine, Center for Hypothalamic Research, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Heng Du
- Department of Pharmacology and Toxicology, The University of Kansas, Lawrence, KS, USA
- Alzheimer’s disease Research Center (ADRC), Department of Neurology, The University of Kansas Medical Center, Kansas City, KS, USA
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14
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Perelló M, Dickson SL, Zigman JM, Leggio L. Toward a consensus nomenclature for ghrelin, its non-acylated form, liver expressed antimicrobial peptide 2 and growth hormone secretagogue receptor. J Neuroendocrinol 2023; 35:e13224. [PMID: 36580314 PMCID: PMC10078427 DOI: 10.1111/jne.13224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 11/11/2022] [Accepted: 11/30/2022] [Indexed: 12/12/2022]
Abstract
The stomach-derived octanoylated peptide ghrelin was discovered in 1999 and recognized as an endogenous agonist of the growth hormone secretagogue receptor (GHSR). Subsequently, ghrelin has been shown to play key roles in controlling not only growth hormone secretion, but also a variety of other physiological functions including, but not limited to, food intake, reward-related behaviors, glucose homeostasis and gastrointestinal tract motility. Importantly, a non-acylated form of ghrelin, desacyl-ghrelin, can also be detected in biological samples. Desacyl-ghrelin, however, does not bind to GHSR at physiological levels, and its physiological role has remained less well-characterized than that of ghrelin. Ghrelin and desacyl-ghrelin are currently referred to in the literature using many different terms, highlighting the need for a consistent nomenclature. The variability of terms used to designate ghrelin can lead not only to confusion, but also to miscommunication, especially for those who are less familiar with the ghrelin literature. Thus, we conducted a survey among experts who have contributed to the ghrelin literature aiming to identify whether a consensus may be reached. Based on the results of this consensus, we propose using the terms "ghrelin" and "desacyl-ghrelin" to refer to the hormone itself and its non-acylated form, respectively. Based on the results of this consensus, we further propose using the terms "GHSR" for the receptor, and "LEAP2" for liver-expressed antimicrobial peptide 2, a recently recognized endogenous GHSR antagonist/inverse agonist.
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Affiliation(s)
- Mario Perelló
- Grupo de Neurofisiología, Instituto Multidisciplinario de Biología Celular (IMBICE), Universidad Nacional La Plata (UNLP), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) y Comisión de Investigaciones Científicas de la Provincia de Buenos Aires (CIC-PBA), La Plata, Argentina
| | - Suzanne L Dickson
- Department of Physiology/Endocrine, Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
| | - Jeffrey M Zigman
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, USA
| | - Lorenzo Leggio
- Clinical Psychoneuroendocrinology and Neuropsychopharmacology Section, Translational Addiction Medicine Branch, National Institute on Drug Abuse Intramural Research Program and National Institute on Alcohol Abuse and Alcoholism Division of Intramural Clinical and Biological Research, National Institutes of Health, Baltimore, MD, USA
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15
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Aguggia JP, Cornejo MP, Fernandez G, De Francesco PN, Mani BK, Cassano D, Cabral A, Valdivia S, García Romero G, Reynaldo M, Fehrentz JA, Zigman JM, Perello M. Growth hormone secretagogue receptor signaling in the supramammillary nucleus targets nitric oxide-producing neurons and controls recognition memory in mice. Psychoneuroendocrinology 2022; 139:105716. [PMID: 35290931 DOI: 10.1016/j.psyneuen.2022.105716] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 02/21/2022] [Accepted: 03/07/2022] [Indexed: 11/27/2022]
Abstract
Ghrelin is a stomach-derived hormone that acts via the growth hormone secretagogue receptor (GHSR). Recent evidence suggests that some of ghrelin's actions may be mediated via the supramammillary nucleus (SuM). Not only does ghrelin bind to cells within the mouse SuM, but ghrelin also activates SuM cells and intra-SuM ghrelin administration induces feeding in rats. In the current study, we aimed to further characterize ghrelin action in the SuM. We first investigated a mouse model expressing enhanced green fluorescent protein (eGFP) under the promoter of GHSR (GHSR-eGFP mice). We found that the SuM of GHSR-eGFP mice contains a significant amount of eGFP cells, some of which express neuronal nitric oxide synthase. Centrally-, but not systemically-, injected ghrelin reached the SuM, where it induced c-Fos expression. Furthermore, a 5-day 40% calorie restriction protocol, but not a 2-day fast, increased c-Fos expression in non-eGFP+ cells of the SuM of GHSR-eGFP mice, whereas c-Fos induction by calorie restriction was not observed in GHSR-deficient mice. Exposure of satiated mice to a binge-like eating protocol also increased c-Fos expression in non-eGFP+ cells of the SuM of GHSR-eGFP mice in a GHSR-dependent manner. Finally, intra-SuM-injected ghrelin did not acutely affect food intake, locomotor activity, behavioral arousal or spatial memory but increased recognition memory. Thus, we provide a compelling neuroanatomical characterization of GHSR SuM neurons and its behavioral implications in mice.
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Affiliation(s)
- Julieta P Aguggia
- Laboratory of Neurophysiology of the Multidisciplinary Institute of Cell Biology [IMBICE, Argentine Research Council (CONICET) and Scientific Research Commission, Province of Buenos Aires (CIC-PBA), National University of La Plata], La Plata, Buenos Aires, Argentina
| | - María P Cornejo
- Laboratory of Neurophysiology of the Multidisciplinary Institute of Cell Biology [IMBICE, Argentine Research Council (CONICET) and Scientific Research Commission, Province of Buenos Aires (CIC-PBA), National University of La Plata], La Plata, Buenos Aires, Argentina
| | - Gimena Fernandez
- Laboratory of Neurophysiology of the Multidisciplinary Institute of Cell Biology [IMBICE, Argentine Research Council (CONICET) and Scientific Research Commission, Province of Buenos Aires (CIC-PBA), National University of La Plata], La Plata, Buenos Aires, Argentina
| | - Pablo N De Francesco
- Laboratory of Neurophysiology of the Multidisciplinary Institute of Cell Biology [IMBICE, Argentine Research Council (CONICET) and Scientific Research Commission, Province of Buenos Aires (CIC-PBA), National University of La Plata], La Plata, Buenos Aires, Argentina
| | - Bharath K Mani
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, USA
| | - Daniela Cassano
- Laboratory of Neurophysiology of the Multidisciplinary Institute of Cell Biology [IMBICE, Argentine Research Council (CONICET) and Scientific Research Commission, Province of Buenos Aires (CIC-PBA), National University of La Plata], La Plata, Buenos Aires, Argentina
| | - Agustina Cabral
- Laboratory of Neurophysiology of the Multidisciplinary Institute of Cell Biology [IMBICE, Argentine Research Council (CONICET) and Scientific Research Commission, Province of Buenos Aires (CIC-PBA), National University of La Plata], La Plata, Buenos Aires, Argentina
| | - Spring Valdivia
- Laboratory of Neurophysiology of the Multidisciplinary Institute of Cell Biology [IMBICE, Argentine Research Council (CONICET) and Scientific Research Commission, Province of Buenos Aires (CIC-PBA), National University of La Plata], La Plata, Buenos Aires, Argentina
| | - Guadalupe García Romero
- Laboratory of Neurophysiology of the Multidisciplinary Institute of Cell Biology [IMBICE, Argentine Research Council (CONICET) and Scientific Research Commission, Province of Buenos Aires (CIC-PBA), National University of La Plata], La Plata, Buenos Aires, Argentina
| | - Mirta Reynaldo
- Laboratory of Neurophysiology of the Multidisciplinary Institute of Cell Biology [IMBICE, Argentine Research Council (CONICET) and Scientific Research Commission, Province of Buenos Aires (CIC-PBA), National University of La Plata], La Plata, Buenos Aires, Argentina
| | - Jean-Alain Fehrentz
- Institut des Biomolécules Max Mousseron, UMR 5247 CNRS-Université Montpellier-ENSCM, Faculté de Pharmacie, Montpellier, France
| | - Jeffrey M Zigman
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, USA
| | - Mario Perello
- Laboratory of Neurophysiology of the Multidisciplinary Institute of Cell Biology [IMBICE, Argentine Research Council (CONICET) and Scientific Research Commission, Province of Buenos Aires (CIC-PBA), National University of La Plata], La Plata, Buenos Aires, Argentina; Department of Surgical Sciences, Functional Pharmacology and Neuroscience, University of Uppsala, Uppsala, Sweden.
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16
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Deschaine SL, Farokhnia M, Gregory-Flores A, Zallar LJ, You ZB, Sun H, Harvey DM, Marchette RCN, Tunstall BJ, Mani BK, Moose JE, Lee MR, Gardner E, Akhlaghi F, Roberto M, Hougland JL, Zigman JM, Koob GF, Vendruscolo LF, Leggio L. A closer look at alcohol-induced changes in the ghrelin system: novel insights from preclinical and clinical data. Addict Biol 2022; 27:e13033. [PMID: 33908131 PMCID: PMC8548413 DOI: 10.1111/adb.13033] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 01/16/2021] [Accepted: 03/06/2021] [Indexed: 02/06/2023]
Abstract
Ghrelin is a gastric-derived peptide hormone with demonstrated impact on alcohol intake and craving, but the reverse side of this bidirectional link, that is, the effects of alcohol on the ghrelin system, remains to be fully established. To further characterize this relationship, we examined (1) ghrelin levels via secondary analysis of human laboratory alcohol administration experiments with heavy-drinking participants; (2) expression of ghrelin, ghrelin receptor, and ghrelin-O-acyltransferase (GOAT) genes (GHRL, GHSR, and MBOAT4, respectively) in post-mortem brain tissue from individuals with alcohol use disorder (AUD) versus controls; (3) ghrelin levels in Ghsr knockout and wild-type rats following intraperitoneal (i.p.) alcohol administration; (4) effect of alcohol on ghrelin secretion from gastric mucosa cells ex vivo and GOAT enzymatic activity in vitro; and (5) ghrelin levels in rats following i.p. alcohol administration versus a calorically equivalent non-alcoholic sucrose solution. Acyl- and total-ghrelin levels decreased following acute alcohol administration in humans, but AUD was not associated with changes in central expression of ghrelin system genes in post-mortem tissue. In rats, alcohol decreased acyl-ghrelin, but not des-acyl-ghrelin, in both Ghsr knockout and wild-type rats. No dose-dependent effects of alcohol were observed on acyl-ghrelin secretion from gastric mucosa cells or on GOAT acylation activity. Lastly, alcohol and sucrose produced distinct effects on ghrelin in rats despite equivalent caloric value. Our findings suggest that alcohol acutely decreases peripheral ghrelin concentrations in vivo, but not in proportion to alcohol's caloric value or through direct interaction with ghrelin-secreting gastric mucosal cells, the ghrelin receptor, or the GOAT enzyme.
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Affiliation(s)
- Sara L. Deschaine
- Clinical Psychoneuroendocrinology and Neuropsychopharmacology Section, Translational Addiction Medicine Branch, National Institute on Drug Abuse and National, Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Baltimore, Maryland, USA
| | - Mehdi Farokhnia
- Clinical Psychoneuroendocrinology and Neuropsychopharmacology Section, Translational Addiction Medicine Branch, National Institute on Drug Abuse and National, Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Baltimore, Maryland, USA,Center on Compulsive Behaviors, National Institutes of Health, Bethesda, Maryland, USA,Johns Hopkins Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, USA
| | - Adriana Gregory-Flores
- Clinical Psychoneuroendocrinology and Neuropsychopharmacology Section, Translational Addiction Medicine Branch, National Institute on Drug Abuse and National, Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Baltimore, Maryland, USA,Neurobiology of Addiction Section, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Baltimore, Maryland, USA
| | - Lia J. Zallar
- Clinical Psychoneuroendocrinology and Neuropsychopharmacology Section, Translational Addiction Medicine Branch, National Institute on Drug Abuse and National, Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Baltimore, Maryland, USA,Neurobiology of Addiction Section, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Baltimore, Maryland, USA
| | - Zhi-Bing You
- Neuropsychopharmacology Section, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse, National Institutes of Health, Baltimore, Maryland, USA
| | - Hui Sun
- Clinical Core Laboratory, Office of the Clinical Director, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland, USA
| | - Deon M. Harvey
- Office of the Scientific Director, National Institute on Drug Abuse, Baltimore, Maryland, USA
| | - Renata C. N. Marchette
- Center on Compulsive Behaviors, National Institutes of Health, Bethesda, Maryland, USA,Neurobiology of Addiction Section, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Baltimore, Maryland, USA
| | - Brendan J. Tunstall
- Neurobiology of Addiction Section, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Baltimore, Maryland, USA
| | - Bharath K. Mani
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Jacob E. Moose
- Syracuse Biomaterials Institute, Syracuse University, Syracuse, New York, USA,Department of Chemistry, Syracuse University, Syracuse, New York, USA
| | - Mary R. Lee
- Clinical Psychoneuroendocrinology and Neuropsychopharmacology Section, Translational Addiction Medicine Branch, National Institute on Drug Abuse and National, Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Baltimore, Maryland, USA
| | - Eliot Gardner
- Neuropsychopharmacology Section, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse, National Institutes of Health, Baltimore, Maryland, USA
| | - Fatemeh Akhlaghi
- Clinical Pharmacokinetics Research Laboratory, Department of Biomedical and Pharmaceutical Sciences, University of Rhode Island, Kingston, Rhode Island, USA
| | - Marisa Roberto
- Department of Neuroscience, The Scripps Research Institute, La Jolla, California, USA
| | - James L. Hougland
- Syracuse Biomaterials Institute, Syracuse University, Syracuse, New York, USA,Department of Chemistry, Syracuse University, Syracuse, New York, USA,BioInspired Syracuse, Syracuse University, Syracuse, New York, USA
| | - Jeffrey M. Zigman
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas, USA,Division of Endocrinology, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas, USA,Department of Psychiatry, UT Southwestern Medical Center, Dallas, Texas, USA
| | - George F. Koob
- Neurobiology of Addiction Section, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Baltimore, Maryland, USA
| | - Leandro F. Vendruscolo
- Neurobiology of Addiction Section, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Baltimore, Maryland, USA
| | - Lorenzo Leggio
- Clinical Psychoneuroendocrinology and Neuropsychopharmacology Section, Translational Addiction Medicine Branch, National Institute on Drug Abuse and National, Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Baltimore, Maryland, USA,Center on Compulsive Behaviors, National Institutes of Health, Bethesda, Maryland, USA,Medication Development Program, National Institute on Drug Abuse Intramural Research Program, National Institutes of Health, Baltimore, Maryland, USA,Center for Alcohol and Addiction Studies, Department of Behavioral and Social Sciences, School of Public Health, Brown University, Providence, Rhode Island, USA,Division of Addiction Medicine, Department of Medicine, School of Medicine, Johns Hopkins University, Baltimore, Maryland, USA,Department of Neuroscience, Georgetown University Medical Center, Washington, District of Columbia, USA
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17
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Gupta D, Dowsett GKC, Mani BK, Shankar K, Osborne-Lawrence S, Metzger NP, Lam BYH, Yeo GSH, Zigman JM. High Coexpression of the Ghrelin and LEAP2 Receptor GHSR With Pancreatic Polypeptide in Mouse and Human Islets. Endocrinology 2021; 162:6325122. [PMID: 34289060 PMCID: PMC8379901 DOI: 10.1210/endocr/bqab148] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/06/2021] [Indexed: 02/07/2023]
Abstract
Islets represent an important site of direct action of the hormone ghrelin, with expression of the ghrelin receptor (growth hormone secretagogue receptor; GHSR) having been localized variably to alpha cells, beta cells, and/or somatostatin (SST)-secreting delta cells. To our knowledge, GHSR expression by pancreatic polypeptide (PP)-expressing gamma cells has not been specifically investigated. Here, histochemical analyses of Ghsr-IRES-Cre × Cre-dependent ROSA26-yellow fluorescent protein (YFP) reporter mice showed 85% of GHSR-expressing islet cells coexpress PP, 50% coexpress SST, and 47% coexpress PP + SST. Analysis of single-cell transcriptomic data from mouse pancreas revealed 95% of Ghsr-expressing cells coexpress Ppy, 100% coexpress Sst, and 95% coexpress Ppy + Sst. This expression was restricted to gamma-cell and delta-cell clusters. Analysis of several single-cell human pancreatic transcriptome data sets revealed 59% of GHSR-expressing cells coexpress PPY, 95% coexpress SST, and 57% coexpress PPY + SST. This expression was prominent in delta-cell and beta-cell clusters, also occurring in other clusters including gamma cells and alpha cells. GHSR expression levels were upregulated by type 2 diabetes mellitus in beta cells. In mice, plasma PP positively correlated with fat mass and with plasma levels of the endogenous GHSR antagonist/inverse agonist LEAP2. Plasma PP also elevated on LEAP2 and synthetic GHSR antagonist administration. These data suggest that in addition to delta cells, beta cells, and alpha cells, PP-expressing pancreatic cells likely represent important direct targets for LEAP2 and/or ghrelin both in mice and humans.
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Affiliation(s)
- Deepali Gupta
- Center for Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9077, USA
| | - Georgina K C Dowsett
- Medical Research Council (MRC) Metabolic Diseases Unit, University of Cambridge Metabolic Research Laboratories, Wellcome Trust–MRC Institute of Metabolic Science, Addenbrooke’s Hospital, Cambridge CB2 0QQ, UK
| | - Bharath K Mani
- Center for Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9077, USA
| | - Kripa Shankar
- Center for Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9077, USA
| | - Sherri Osborne-Lawrence
- Center for Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9077, USA
| | - Nathan P Metzger
- Center for Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9077, USA
| | - Brian Y H Lam
- Medical Research Council (MRC) Metabolic Diseases Unit, University of Cambridge Metabolic Research Laboratories, Wellcome Trust–MRC Institute of Metabolic Science, Addenbrooke’s Hospital, Cambridge CB2 0QQ, UK
| | - Giles S H Yeo
- Medical Research Council (MRC) Metabolic Diseases Unit, University of Cambridge Metabolic Research Laboratories, Wellcome Trust–MRC Institute of Metabolic Science, Addenbrooke’s Hospital, Cambridge CB2 0QQ, UK
- Correspondence: Giles S. H. Yeo, PhD, Metabolic Diseases Unit, University of Cambridge Metabolic Research Laboratories, Wellcome–MRC Institute of Metabolic Science, Box 289, Addenbrooke’s Hospital, Hills Rd, Cambridge, CB2 0QQ, UK.
| | - Jeffrey M Zigman
- Center for Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9077, USA
- Division of Endocrinology, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9077, USA
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9077, USA
- Correspondence: Jeffrey M. Zigman, MD, PhD, Center for Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, MC9077, Dallas, TX 75390-9077, USA.
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18
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Shankar K, Takemi S, Gupta D, Varshney S, Mani BK, Osborne-Lawrence S, Metzger NP, Richard CP, Berglund ED, Zigman JM. Ghrelin cell-expressed insulin receptors mediate meal- and obesity-induced declines in plasma ghrelin. JCI Insight 2021; 6:e146983. [PMID: 34473648 PMCID: PMC8492315 DOI: 10.1172/jci.insight.146983] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Accepted: 08/04/2021] [Indexed: 01/20/2023] Open
Abstract
Mechanisms underlying postprandial and obesity-associated plasma ghrelin reductions are incompletely understood. Here, using ghrelin cell-selective insulin receptor-KO (GhIRKO) mice, we tested the impact of insulin, acting via ghrelin cell-expressed insulin receptors (IRs), to suppress ghrelin secretion. Insulin reduced ghrelin secretion from cultured gastric mucosal cells of control mice but not from those of GhIRKO mice. Acute insulin challenge and insulin infusion during both hyperinsulinemic-hypoglycemic clamps and hyperinsulinemic-euglycemic clamps lowered plasma ghrelin in control mice but not GhIRKO mice. Thus, ghrelin cell-expressed IRs are required for insulin-mediated reductions in plasma ghrelin. Furthermore, interventions that naturally raise insulin (glucose gavage, refeeding following fasting, and chronic high-fat diet) also lowered plasma ghrelin only in control mice - not GhIRKO mice. Thus, meal- and obesity-associated increases in insulin, acting via ghrelin cell-expressed IRs, represent a major, direct negative modulator of ghrelin secretion in vivo, as opposed to ingested or metabolized macronutrients. Refed GhIRKO mice exhibited reduced plasma insulin, highlighting ghrelin's actions to inhibit insulin release via a feedback loop. Moreover, GhIRKO mice required reduced glucose infusion rates during hyperinsulinemic-hypoglycemic clamps, suggesting that suppressed ghrelin release resulting from direct insulin action on ghrelin cells usually limits ghrelin's full potential to protect against insulin-induced hypoglycemia.
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Affiliation(s)
- Kripa Shankar
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Shota Takemi
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas, USA
- Area of Regulatory Biology, Division of Life Science, Graduate School of Science and Engineering, Saitama University, Sakuraku, Saitama, Japan
| | - Deepali Gupta
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Salil Varshney
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Bharath K. Mani
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Sherri Osborne-Lawrence
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Nathan P. Metzger
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Corine P. Richard
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Eric D. Berglund
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Jeffrey M. Zigman
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas, USA
- Division of Endocrinology, Department of Internal Medicine, and
- Department of Psychiatry, UT Southwestern Medical Center, Dallas, Texas, USA
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19
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Shankar K, Metzger NP, Singh O, Mani BK, Osborne-Lawrence S, Varshney S, Gupta D, Ogden SB, Takemi S, Richard CP, Nandy K, Liu C, Zigman JM. LEAP2 deletion in mice enhances ghrelin's actions as an orexigen and growth hormone secretagogue. Mol Metab 2021; 53:101327. [PMID: 34428557 PMCID: PMC8452786 DOI: 10.1016/j.molmet.2021.101327] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 08/13/2021] [Accepted: 08/19/2021] [Indexed: 02/03/2023] Open
Abstract
Objective The hormone liver-expressed antimicrobial peptide-2 (LEAP2) is a recently identified antagonist and an inverse agonist of the growth hormone secretagogue receptor (GHSR). GHSR's other well-known endogenous ligand, acyl-ghrelin, increases food intake, body weight, and GH secretion and is lowered in obesity but elevated upon fasting. In contrast, LEAP2 reduces acyl-ghrelin-induced food intake and GH secretion and is found elevated in obesity but lowered upon fasting. Thus, the plasma LEAP2/acyl-ghrelin molar ratio could be a key determinant modulating GHSR signaling in response to changes in body mass and feeding status. In particular, LEAP2 may serve to dampen acyl-ghrelin action in the setting of obesity, which is associated with ghrelin resistance. Here, we sought to determine the metabolic effects of genetic LEAP2 deletion. Methods We generated the first known LEAP2-KO mouse line. Food intake, GH secretion, and cellular activation (c-fos induction) in different brain regions following s.c. acyl-ghrelin administration in LEAP2-KO mice and wild-type littermates were determined. LEAP2-KO mice and wild-type littermates were submitted to a battery of tests (such as measurements of body weight, food intake, and body composition; indirect calorimetry, determination of locomotor activity, and meal patterning while housed in metabolic cages) over the course of 16 weeks of high-fat diet and/or standard chow feeding. Fat accumulation was assessed in hematoxylin & eosin-stained and oil red O-stained liver sections from these mice. Results LEAP2-KO mice were more sensitive to s.c. ghrelin. In particular, acyl-ghrelin acutely stimulated food intake at a dose of 0.5 mg/kg BW in standard chow-fed LEAP2-KO mice while a 2× higher dose was required by wild-type littermates. Also, acyl-ghrelin stimulated food intake at a dose of 1 mg/kg BW in high-fat diet-fed LEAP2-KO mice while not even a 10× higher dose was effective in wild-type littermates. Acyl-ghrelin induced a 90.9% higher plasma GH level and 77.2–119.7% higher numbers of c-fos-immunoreactive cells in the arcuate nucleus and olfactory bulb, respectively, in LEAP2-KO mice than in wild-type littermates. LEAP2 deletion raised body weight (by 15.0%), food intake (by 18.4%), lean mass (by 6.1%), hepatic fat (by 42.1%), and body length (by 1.7%) in females on long-term high-fat diet as compared to wild-type littermates. After only 4 weeks on the high-fat diet, female LEAP2-KO mice exhibited lower O2 consumption (by 13%), heat production (by 9.5%), and locomotor activity (by 49%) than by wild-type littermates during the first part of the dark period. These genotype-dependent differences were not observed in high-fat diet-exposed males or female and male mice exposed for long term to standard chow diet. Conclusions LEAP2 deletion sensitizes lean and obese mice to the acute effects of administered acyl-ghrelin on food intake and GH secretion. LEAP2 deletion increases body weight in females chronically fed a high-fat diet as a result of lowered energy expenditure, reduced locomotor activity, and increased food intake. Furthermore, in female mice, LEAP2 deletion increases body length and exaggerates the hepatic fat accumulation normally associated with chronic high-fat diet feeding. A novel line of LEAP2-knockout mice was generated. LEAP2 deletion sensitizes mice to the GH secretory effects of administered ghrelin. LEAP2 deletion reduces ghrelin resistance in diet-induced obese mice. HFD-fed female LEAP2-KO mice eat more and gain more body weight and hepatic fat. HFD-fed female LEAP2-KO mice exhibit lowered energy expenditure and activity.
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Affiliation(s)
- Kripa Shankar
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, USA
| | - Nathan P Metzger
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, USA
| | - Omprakash Singh
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, USA
| | - Bharath K Mani
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, USA
| | - Sherri Osborne-Lawrence
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, USA
| | - Salil Varshney
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, USA
| | - Deepali Gupta
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, USA
| | - Sean B Ogden
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, USA
| | - Shota Takemi
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, USA
| | - Corine P Richard
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, USA
| | - Karabi Nandy
- Division of Biostatistics, Department of Population and Data Sciences, UT Southwestern Medical Center, Dallas, TX, USA
| | - Chen Liu
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, USA; Department of Neuroscience, UT Southwestern Medical Center, Dallas, TX, USA
| | - Jeffrey M Zigman
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, USA; Division of Endocrinology, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, USA; Department of Psychiatry, UT Southwestern Medical Center, Dallas, TX, USA.
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20
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Gupta D, Patterson AM, Osborne-Lawrence S, Bookout AL, Varshney S, Shankar K, Singh O, Metzger NP, Richard CP, Wyler SC, Elmquist JK, Zigman JM. Disrupting the ghrelin-growth hormone axis limits ghrelin's orexigenic but not glucoregulatory actions. Mol Metab 2021; 53:101258. [PMID: 34023483 PMCID: PMC8203846 DOI: 10.1016/j.molmet.2021.101258] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 04/26/2021] [Accepted: 05/14/2021] [Indexed: 12/19/2022] Open
Abstract
Objective Acyl-ghrelin regulates eating, body weight, blood glucose, and GH secretion upon binding to its receptor GHSR (growth hormone secretagogue receptor; ghrelin receptor). GHSR is distributed in several brain regions and some peripheral cell-types including pituitary somatotrophs. The objective of the current study was to determine the functional significance of acyl-ghrelin's action on GHSR-expressing somatotrophs in mediating GH secretion and several of acyl-ghrelin's metabolic actions. Methods GH-IRES-Cre mice and loxP-flanked (floxed) GHSR mice were newly developed and then crossed to one another to generate mice that lacked GHSR selectively from somatotrophs. Following validation of mice with somatotroph-selective GHSR deletion, metabolic responses of these mice and control littermates were assessed following both acute and chronic acyl-ghrelin administration, a 24-h fast, and a prolonged 60% chronic caloric restriction protocol modeling starvation. Results In mice with somatotroph-selective GHSR deletion, a single peripheral injection of acyl-ghrelin failed to induce GH secretion or increase food intake, unlike wild-type and other littermate control groups. However, the usual acute blood glucose increase in response to the acyl-ghrelin bolus was preserved. Similarly, chronic s.c. acyl-ghrelin administration to mice with somatotroph-selective GHSR deletion failed to increase plasma GH, food intake, or body weight. Physiologically elevating plasma acyl-ghrelin via a 24-h fast also failed to raise plasma GH and resulted in a limited hyperphagic response upon food reintroduction in mice with somatotroph-selective GHSR deletion, although those mice nonetheless did not exhibit an exaggerated reduction in blood glucose. Physiologically elevating plasma acyl-ghrelin via a 15-day caloric restriction protocol which provided only 40% of usual daily calories failed to raise plasma GH in mice with somatotroph-selective GHSR deletion, although those mice did not exhibit life-threatening hypoglycemia. Conclusions These results reveal that direct engagement of GHSR-expressing somatotrophs is required for a peripheral ghrelin bolus to acutely stimulate GH secretion and the actions of chronic acyl-ghrelin delivery and physiological plasma acyl-ghrelin elevations to increase plasma GH. These results also suggest that actions of acyl-ghrelin to increase food intake and body weight are reliant on direct activation of GHSRs expressed on somatotrophs. Furthermore, these results suggest that the glucoregulatory actions of acyl-ghrelin – in particular, its actions to raise blood glucose when acutely administered, prevent small blood glucose drops following a 24-h fast, and avert life-threatening hypoglycemia during an acute-on-chronic caloric restriction protocol – do not depend on GHSR expression by somatotrophs. Mice with pituitary somatotroph-selective GHSR deletion were generated. Somatotroph-expressed GHSRs mediate GH secretion and food intake after acute ghrelin. Body weight effects of chronic ghrelin infusion require somatotroph-expressed GHSRs. Somatotroph-expressed GHSRs enable GH to increase upon chronic caloric restriction. Mice lacking somatotroph GHSRs maintain euglycemia upon chronic caloric restriction.
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Affiliation(s)
- Deepali Gupta
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, USA
| | - Anna M Patterson
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, USA
| | - Sherri Osborne-Lawrence
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, USA
| | - Angie L Bookout
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, USA
| | - Salil Varshney
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, USA
| | - Kripa Shankar
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, USA
| | - Omprakash Singh
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, USA
| | - Nathan P Metzger
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, USA
| | - Corine P Richard
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, USA
| | - Steven C Wyler
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, USA
| | - Joel K Elmquist
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, USA; Division of Endocrinology, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, USA; Department of Psychiatry, UT Southwestern Medical Center, Dallas, TX, USA
| | - Jeffrey M Zigman
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, USA; Division of Endocrinology, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, USA; Department of Psychiatry, UT Southwestern Medical Center, Dallas, TX, USA.
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21
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Peris-Sampedro F, Stoltenborg I, Le May MV, Zigman JM, Adan RAH, Dickson SL. Genetic deletion of the ghrelin receptor (GHSR) impairs growth and blunts endocrine response to fasting in Ghsr-IRES-Cre mice. Mol Metab 2021; 51:101223. [PMID: 33798772 PMCID: PMC8102639 DOI: 10.1016/j.molmet.2021.101223] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 03/22/2021] [Accepted: 03/24/2021] [Indexed: 12/13/2022] Open
Abstract
OBJECTIVE The orexigenic hormone ghrelin exerts its physiological effects by binding to and activating the growth hormone secretagogue receptor (GHSR). The recent development of a Ghsr-IRES-Cre knock-in mouse line has enabled to genetically access GHSR-expressing neurons. Inserting a Cre construct using a knock-in strategy, even when following an upstream internal ribosome entry site (IRES) can, however, interfere with expression of a targeted gene, with consequences for the phenotype emerging. This study aimed to phenotype, both physically and metabolically, heterozygous and homozygous Ghsr-IRES-Cre mice, with a view to discovering the extent to which the ghrelin signalling system remains functional in these mice. METHODS We assessed feeding and arcuate nucleus (Arc) Fos activation in wild-type, heterozygous and homozygous Ghsr-IRES-Cre mice in response to peripherally-administered ghrelin. We also characterised their developmental and growth phenotypes, as well as their metabolic responses upon an overnight fast. RESULTS Insertion of the IRES-Cre cassette into the 3'-untranslated region of the Ghsr gene led to a gene-dosage GHSR depletion in the Arc. Whereas heterozygotes remained ghrelin-responsive and more closely resembled wild-types, ghrelin had reduced orexigenic efficacy and failed to induce Arc Fos expression in homozygous littermates. Homozygotes had a lower body weight accompanied by a shorter body length, less fat tissue content, altered bone parameters, and lower insulin-like growth factor-1 levels compared to wild-type and heterozygous littermates. Moreover, both heterozygous and homozygous Ghsr-IRES-Cre mice lacked the usual fasting-induced rise in growth hormone (GH) and displayed an exaggerated drop in blood glucose and insulin compared to wild-types. Unexpectedly, fasting acyl-ghrelin levels were allele-dependently increased. CONCLUSIONS Our data suggest that (i) heterozygous but not homozygous Ghsr-IRES-Cre mice retain the usual responsiveness to administered ghrelin, (ii) the impact of fasting on GH release and glucose homeostasis is altered even when only one copy of the Ghsr gene is non-functional (as in heterozygous Ghsr-IRES-Cre mice) and (iii) homozygous Ghsr-IRES-Cre mice exhibit growth retardation. Of the many transgenic models of suppressed ghrelin signalling, Ghsr-IRES-Cre mice emerge as best representing the full breadth of the expected phenotype with respect to body weight, growth, and metabolic parameters.
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Affiliation(s)
- Fiona Peris-Sampedro
- Department of Physiology/Endocrinology, Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
| | - Iris Stoltenborg
- Department of Physiology/Endocrinology, Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
| | - Marie V Le May
- Department of Physiology/Endocrinology, Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
| | - Jeffrey M Zigman
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, USA; Division of Endocrinology, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, USA; Department of Psychiatry, UT Southwestern Medical Center, Dallas, TX, USA
| | - Roger A H Adan
- Department of Physiology/Endocrinology, Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden; Department of Translational Neuroscience, UMC Utrecht Brain Center, Utrecht University, Utrecht, The Netherlands
| | - Suzanne L Dickson
- Department of Physiology/Endocrinology, Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden.
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22
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Abstract
Ghrelin is a predominantly stomach-derived peptide hormone with many actions including regulation of food intake, body weight, and blood glucose. Plasma ghrelin levels are robustly regulated by feeding status, with its levels increasing upon caloric restriction and decreasing after food intake. At least some of this regulation might be due to direct responsiveness of ghrelin cells to changes in circulating nutrients, including glucose. Indeed, oral and parental glucose administration to humans and mice lower plasma ghrelin. Also, dissociated mouse gastric mucosal cell preparations, which contain ghrelin cells, decrease ghrelin secretion when cultured in high ambient glucose. Here, we used primary cultures of mouse gastric mucosal cells in combination with an array of pharmacological tools to examine the potential role of changed intracellular oxidative stress in glucose-restricted ghrelin secretion. The antioxidants resveratrol, SRT1720, and curcumin all markedly increased ghrelin secretion. Furthermore, three different selective activators of Nuclear factor erythroid-derived-2-like 2 (Nrf2), a master regulator of the antioxidative cellular response to oxidative stress, increased ghrelin secretion. These antioxidant compounds blocked the inhibitory effects of glucose on ghrelin secretion. Therefore, we conclude that lowering oxidative stress within ghrelin cells stimulates ghrelin secretion and blocks the direct effects of glucose on ghrelin cells to inhibit ghrelin secretion.
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Affiliation(s)
- Bharath K Mani
- Center for Hypothalamic Research and Division of Endocrinology, Department of Internal Medicine and Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Sherri Osborne-Lawrence
- Center for Hypothalamic Research and Division of Endocrinology, Department of Internal Medicine and Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Nathan Metzger
- Center for Hypothalamic Research and Division of Endocrinology, Department of Internal Medicine and Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Jeffrey M Zigman
- Center for Hypothalamic Research and Division of Endocrinology, Department of Internal Medicine and Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, Texas
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23
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Tian J, Guo L, Sui S, Driskill C, Phensy A, Wang Q, Gauba E, Zigman JM, Swerdlow RH, Kroener S, Du H. Disrupted hippocampal growth hormone secretagogue receptor 1α interaction with dopamine receptor D1 plays a role in Alzheimer's disease. Sci Transl Med 2020; 11:11/505/eaav6278. [PMID: 31413143 PMCID: PMC6776822 DOI: 10.1126/scitranslmed.aav6278] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Accepted: 06/24/2019] [Indexed: 12/12/2022]
Abstract
Hippocampal lesions are a defining pathology of Alzheimer's disease (AD). However, the molecular mechanisms that underlie hippocampal synaptic injury in AD have not been fully elucidated. Current therapeutic efforts for AD treatment are not effective in correcting hippocampal synaptic deficits. Growth hormone secretagogue receptor 1α (GHSR1α) is critical for hippocampal synaptic physiology. Here, we report that GHSR1α interaction with β-amyloid (Aβ) suppresses GHSR1α activation, leading to compromised GHSR1α regulation of dopamine receptor D1 (DRD1) in the hippocampus from patients with AD. The simultaneous application of the selective GHSR1α agonist MK0677 with the selective DRD1 agonist SKF81297 rescued Ghsr1α function from Aβ inhibition, mitigating hippocampal synaptic injury and improving spatial memory in an AD mouse model. Our data reveal a mechanism of hippocampal vulnerability in AD and suggest that a combined activation of GHSR1α and DRD1 may be a promising approach for treating AD.
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Affiliation(s)
- Jing Tian
- Department of Biological Sciences, University of Texas at Dallas, Richardson, TX 75080, USA
| | - Lan Guo
- Department of Biological Sciences, University of Texas at Dallas, Richardson, TX 75080, USA
| | - Shaomei Sui
- Department of Biological Sciences, University of Texas at Dallas, Richardson, TX 75080, USA.,Department of Neurology, Qianfoshan Hospital, Shandong First Medical University, Jinan, Shandong 250014, China
| | - Christopher Driskill
- School of Behavioral and Brain Sciences, University of Texas at Dallas, Richardson, TX 75080, USA
| | - Aarron Phensy
- School of Behavioral and Brain Sciences, University of Texas at Dallas, Richardson, TX 75080, USA
| | - Qi Wang
- Department of Biological Sciences, University of Texas at Dallas, Richardson, TX 75080, USA.,Department of Neurology, Qianfoshan Hospital, Shandong First Medical University, Jinan, Shandong 250014, China
| | - Esha Gauba
- Department of Biological Sciences, University of Texas at Dallas, Richardson, TX 75080, USA
| | - Jeffrey M Zigman
- Department of Internal Medicine, Division of Hypothalamic Research, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Russell H Swerdlow
- Department of Neurology, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Sven Kroener
- School of Behavioral and Brain Sciences, University of Texas at Dallas, Richardson, TX 75080, USA
| | - Heng Du
- Department of Biological Sciences, University of Texas at Dallas, Richardson, TX 75080, USA.
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24
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Michael NJ, Zigman JM, Williams KW, Elmquist JK. Electrophysiological Properties of Genetically Identified Histaminergic Neurons. Neuroscience 2020; 444:183-195. [PMID: 32599122 DOI: 10.1016/j.neuroscience.2020.06.031] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2020] [Revised: 06/17/2020] [Accepted: 06/19/2020] [Indexed: 11/27/2022]
Abstract
Histaminergic neurons of the tuberomammillary nucleus (TMN) are important regulators of behavioral and homeostatic processes. Previous work suggested that histaminergic neurons exhibit a characteristic electrophysiological signature, allowing for their identification in brain slice preparations. However, these previous investigations focused on neurons in the ventral subregion of the TMN of rats. Consequently, it remains unclear whether such electrophysiological properties extend to mice, including other subregions of the TMN, and the potential for differences between males and females. To further characterize the electrophysiological properties of histaminergic neurons, we performed whole-cell patch-clamp recordings on transgenic mice expressing Cre recombinase in histidine decarboxylase (HDC)-expressing cells; the sole enzyme for histamine synthesis (Hdc-cre::tdTomato). Despite similarities with the electrophysiological properties reported in rats, we observed considerable variability in mouse HDC neuron passive membrane properties, action potential firing, and intrinsic subthreshold active membrane properties. Overall, the electrophysiological properties of HDC neurons appeared similar across subregions of the TMN, consistent with a lack of topographical organization in this nucleus. Moreover, we found no obvious sex differences in the electrical excitability of HDC neurons. However, our data reveal a diversity in the electrophysiological properties of genetically identified histaminergic neurons from mice not previously appreciated from rat studies. Thus, these data highlight the utility of mouse genetics to target the widespread histaminergic neuronal population within the TMN and support the idea that histaminergic neurons are a heterogeneous neuronal population.
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Affiliation(s)
- Natalie J Michael
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX 75390-9077, United States; Institut Universitaire de Cardiologie et de Pneumologie de Québec, Québec, QC G1V 4G5, Canada
| | - Jeffrey M Zigman
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX 75390-9077, United States
| | - Kevin W Williams
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX 75390-9077, United States.
| | - Joel K Elmquist
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX 75390-9077, United States; Department of Pharmacology, UT Southwestern Medical Center, Dallas, TX 75390-9077, United States.
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25
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Mani BK, Puzziferri N, He Z, Rodriguez JA, Osborne-Lawrence S, Metzger NP, Chhina N, Gaylinn B, Thorner MO, Thomas EL, Bell JD, Williams KW, Goldstone AP, Zigman JM. LEAP2 changes with body mass and food intake in humans and mice. J Clin Invest 2020; 129:3909-3923. [PMID: 31424424 DOI: 10.1172/jci125332] [Citation(s) in RCA: 109] [Impact Index Per Article: 27.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Accepted: 06/11/2019] [Indexed: 12/11/2022] Open
Abstract
Acyl-ghrelin administration increases food intake, body weight, and blood glucose. In contrast, mice lacking ghrelin or ghrelin receptors (GHSRs) exhibit life-threatening hypoglycemia during starvation-like conditions, but do not consistently exhibit overt metabolic phenotypes when given ad libitum food access. These results, and findings of ghrelin resistance in obese states, imply nutritional state dependence of ghrelin's metabolic actions. Here, we hypothesized that liver-enriched antimicrobial peptide-2 (LEAP2), a recently characterized endogenous GHSR antagonist, blunts ghrelin action during obese states and postprandially. To test this hypothesis, we determined changes in plasma LEAP2 and acyl-ghrelin due to fasting, eating, obesity, Roux-en-Y gastric bypass (RYGB), vertical sleeve gastrectomy (VSG), oral glucose administration, and type 1 diabetes mellitus (T1DM) using humans and/or mice. Our results suggest that plasma LEAP2 is regulated by metabolic status: its levels increased with body mass and blood glucose and decreased with fasting, RYGB, and in postprandial states following VSG. These changes were mostly opposite of those of acyl-ghrelin. Furthermore, using electrophysiology, we showed that LEAP2 both hyperpolarizes and prevents acyl-ghrelin from activating arcuate NPY neurons. We predict that the plasma LEAP2/acyl-ghrelin molar ratio may be a key determinant modulating acyl-ghrelin activity in response to body mass, feeding status, and blood glucose.
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Affiliation(s)
- Bharath K Mani
- Division of Hypothalamic Research.,Division of Endocrinology & Metabolism, Department of Internal Medicine.,Department of Psychiatry, and
| | - Nancy Puzziferri
- Department of Surgery, UT Southwestern Medical Center, Dallas, Texas, USA.,Department of Surgery, Veterans Administration North Texas Heath Care System, Dallas, Texas, USA
| | | | - Juan A Rodriguez
- Division of Hypothalamic Research.,Division of Endocrinology & Metabolism, Department of Internal Medicine.,Department of Psychiatry, and
| | - Sherri Osborne-Lawrence
- Division of Hypothalamic Research.,Division of Endocrinology & Metabolism, Department of Internal Medicine.,Department of Psychiatry, and
| | - Nathan P Metzger
- Division of Hypothalamic Research.,Division of Endocrinology & Metabolism, Department of Internal Medicine.,Department of Psychiatry, and
| | - Navpreet Chhina
- PsychoNeuroEndocrinology Research Group, Neuropsychopharmacology Unit, Centre for Psychiatry, and.,Computational, Cognitive and Clinical Neuroimaging Laboratory, Division of Brain Sciences, Imperial College London, Hammersmith Hospital, London, United Kingdom
| | - Bruce Gaylinn
- Department of Endocrinology, University of Virginia, Charlottesville, Virginia, USA
| | - Michael O Thorner
- Department of Endocrinology, University of Virginia, Charlottesville, Virginia, USA
| | - E Louise Thomas
- Research Centre for Optimal Health, University of Westminster, London, United Kingdom
| | - Jimmy D Bell
- Research Centre for Optimal Health, University of Westminster, London, United Kingdom
| | | | - Anthony P Goldstone
- PsychoNeuroEndocrinology Research Group, Neuropsychopharmacology Unit, Centre for Psychiatry, and.,Computational, Cognitive and Clinical Neuroimaging Laboratory, Division of Brain Sciences, Imperial College London, Hammersmith Hospital, London, United Kingdom
| | - Jeffrey M Zigman
- Division of Hypothalamic Research.,Division of Endocrinology & Metabolism, Department of Internal Medicine.,Department of Psychiatry, and
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26
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Michael NJ, Caron A, Lee CE, Castorena CM, Lee S, Zigman JM, Williams KW, Elmquist JK. Melanocortin regulation of histaminergic neurons via perifornical lateral hypothalamic melanocortin 4 receptors. Mol Metab 2020; 35:100956. [PMID: 32244183 PMCID: PMC7082550 DOI: 10.1016/j.molmet.2020.01.020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Revised: 01/23/2020] [Accepted: 01/28/2020] [Indexed: 12/28/2022] Open
Abstract
OBJECTIVE Histaminergic neurons of the tuberomammillary nucleus (TMN) are wake-promoting and contribute to the regulation of energy homeostasis. Evidence indicates that melanocortin 4 receptors (MC4R) are expressed within the TMN. However, whether the melanocortin system influences the activity and function of TMN neurons expressing histidine decarboxylase (HDC), the enzyme required for histamine synthesis, remains undefined. METHODS We utilized Hdc-Cre mice in combination with whole-cell patch-clamp electrophysiology and in vivo chemogenetic techniques to determine whether HDC neurons receive metabolically relevant information via the melanocortin system. RESULTS We found that subsets of HDC-expressing neurons were excited by melanotan II (MTII), a non-selective melanocortin receptor agonist. Use of melanocortin receptor selective agonists (THIQ, [D-Trp8]-γ-MSH) and inhibitors of synaptic transmission (TTX, CNQX, AP5) indicated that the effect was mediated specifically by MC4Rs and involved a glutamatergic dependent presynaptic mechanism. MTII enhanced evoked excitatory post-synaptic currents (EPSCs) originating from electrical stimulation of the perifornical lateral hypothalamic area (PeFLH), supportive of melanocortin effects on the glutamatergic PeFLH projection to the TMN. Finally, in vivo chemogenetic inhibition of HDC neurons strikingly enhanced the anorexigenic effects of intracerebroventricular administration of MTII, suggesting that MC4R activation of histaminergic neurons may restrain the anorexigenic effects of melanocortin system activation. CONCLUSIONS These experiments identify a functional interaction between the melanocortin and histaminergic systems and suggest that HDC neurons act naturally to restrain the anorexigenic effect of melanocortin system activation. These findings may have implications for the control of arousal and metabolic homeostasis, especially in the context of obesity, in which both processes are subjected to alterations.
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MESH Headings
- Animals
- Behavior, Animal/drug effects
- Eating/drug effects
- Excitatory Postsynaptic Potentials/drug effects
- Histamine/metabolism
- Histidine Decarboxylase/genetics
- Histidine Decarboxylase/metabolism
- Hypothalamic Area, Lateral/cytology
- Hypothalamic Area, Lateral/metabolism
- Locomotion/drug effects
- Male
- Melanocortins/metabolism
- Mice
- Mice, Inbred C57BL
- Mice, Transgenic
- Neurons/drug effects
- Neurons/metabolism
- Peptides, Cyclic/pharmacology
- Receptor, Melanocortin, Type 4/agonists
- Receptor, Melanocortin, Type 4/genetics
- Receptor, Melanocortin, Type 4/metabolism
- alpha-MSH/analogs & derivatives
- alpha-MSH/pharmacology
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Affiliation(s)
- Natalie J Michael
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, 75390-9077, USA
| | - Alexandre Caron
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, 75390-9077, USA
| | - Charlotte E Lee
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, 75390-9077, USA
| | - Carlos M Castorena
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, 75390-9077, USA
| | - Syann Lee
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, 75390-9077, USA
| | - Jeffrey M Zigman
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, 75390-9077, USA
| | - Kevin W Williams
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, 75390-9077, USA.
| | - Joel K Elmquist
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, 75390-9077, USA; Department of Pharmacology, UT Southwestern Medical Center, Dallas, TX, 75390-9077, USA.
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27
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Torz LJ, Osborne-Lawrence S, Rodriguez J, He Z, Cornejo MP, Mustafá ER, Jin C, Petersen N, Hedegaard MA, Nybo M, Damonte VM, Metzger NP, Mani BK, Williams KW, Raingo J, Perello M, Holst B, Zigman JM. Metabolic insights from a GHSR-A203E mutant mouse model. Mol Metab 2020; 39:101004. [PMID: 32339772 PMCID: PMC7242877 DOI: 10.1016/j.molmet.2020.101004] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2020] [Revised: 04/13/2020] [Accepted: 04/16/2020] [Indexed: 02/02/2023] Open
Abstract
Objective Binding of ghrelin to its receptor, growth hormone secretagogue receptor (GHSR), stimulates GH release, induces eating, and increases blood glucose. These processes may also be influenced by constitutive (ghrelin-independent) GHSR activity, as suggested by findings in short people with naturally occurring GHSR-A204E mutations and reduced food intake and blood glucose in rodents administered GHSR inverse agonists, both of which impair constitutive GHSR activity. In this study, we aimed to more fully determine the physiologic relevance of constitutive GHSR activity. Methods We generated mice with a GHSR mutation that replaces alanine at position 203 with glutamate (GHSR-A203E), which corresponds to the previously described human GHSR-A204E mutation, and used them to conduct ex vivo neuronal electrophysiology and in vivo metabolic assessments. We also measured signaling within COS-7 and HEK293T cells transfected with wild-type GHSR (GHSR-WT) or GHSR-A203E constructs. Results In COS-7 cells, GHSR-A203E resulted in lower baseline IP3 accumulation than GHSR-WT; ghrelin-induced IP3 accumulation was observed in both constructs. In HEK293T cells co-transfected with voltage-gated CaV2.2 calcium channel complex, GHSR-A203E had no effect on basal CaV2.2 current density while GHSR-WT did; both GHSR-A203E and GHSR-WT inhibited CaV2.2 current in the presence of ghrelin. In cultured hypothalamic neurons from GHSR-A203E and GHSR-deficient mice, native calcium currents were greater than those in neurons from wild-type mice; ghrelin inhibited calcium currents in cultured hypothalamic neurons from both GHSR-A203E and wild-type mice. In brain slices, resting membrane potentials of arcuate NPY neurons from GHSR-A203E mice were hyperpolarized compared to those from wild-type mice; the same percentage of arcuate NPY neurons from GHSR-A203E and wild-type mice depolarized upon ghrelin exposure. The GHSR-A203E mutation did not significantly affect body weight, body length, or femur length in the first ∼6 months of life, yet these parameters were lower in GHSR-A203E mice after 1 year of age. During a 7-d 60% caloric restriction regimen, GHSR-A203E mice lacked the usual marked rise in plasma GH and demonstrated an exaggerated drop in blood glucose. Administered ghrelin also exhibited reduced orexigenic and GH secretagogue efficacies in GHSR-A203E mice. Conclusions Our data suggest that the A203E mutation ablates constitutive GHSR activity and that constitutive GHSR activity contributes to the native depolarizing conductance of GHSR-expressing arcuate NPY neurons. Although the A203E mutation does not block ghrelin-evoked signaling as assessed using in vitro and ex vivo models, GHSR-A203E mice lack the usual acute food intake response to administered ghrelin in vivo. The GHSR-A203E mutation also blunts GH release, and in aged mice leads to reduced body length and femur length, which are consistent with the short stature of human carriers of the GHSR-A204E mutation. We generated mice with a GHSR mutation replacing Ala at position 203 with Glu. The A203E mutation ablates constitutive GHSR activity & hyperpolarizes NPY neurons. GHSR-A203E mice lack the usual orexigenic response to administered ghrelin. The GHSR-A203E mutation blunts GH release and causes reduced body length. This finding is consistent with short stature in human carriers of the GHSR-A204E mutation.
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Affiliation(s)
- Lola J Torz
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark; Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark
| | - Sherri Osborne-Lawrence
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, USA
| | - Juan Rodriguez
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, USA
| | - Zhenyan He
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, USA
| | | | - Emilio Román Mustafá
- Laboratory of Electrophysiology of the Multidisciplinary Institute of Cell Biology [Argentine Research Council (CONICET) and Scientific Research Commission, Province of Buenos Aires (CIC-PBA)], La Plata, Buenos Aires, Argentina
| | - Chunyu Jin
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Natalia Petersen
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Morten A Hedegaard
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Maja Nybo
- Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark
| | - Valentina Martínez Damonte
- Laboratory of Electrophysiology of the Multidisciplinary Institute of Cell Biology [Argentine Research Council (CONICET) and Scientific Research Commission, Province of Buenos Aires (CIC-PBA)], La Plata, Buenos Aires, Argentina
| | - Nathan P Metzger
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, USA
| | - Bharath K Mani
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, USA
| | - Kevin W Williams
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, USA
| | - Jesica Raingo
- Laboratory of Electrophysiology of the Multidisciplinary Institute of Cell Biology [Argentine Research Council (CONICET) and Scientific Research Commission, Province of Buenos Aires (CIC-PBA)], La Plata, Buenos Aires, Argentina
| | - Mario Perello
- Laboratory of Neurophysiology, La Plata, Buenos Aires, Argentina
| | - Birgitte Holst
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark; Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark.
| | - Jeffrey M Zigman
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, USA.
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28
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Shankar K, Gupta D, Mani BK, Findley BG, Lord CC, Osborne-Lawrence S, Metzger NP, Pietra C, Liu C, Berglund ED, Zigman JM. Acyl-ghrelin Is Permissive for the Normal Counterregulatory Response to Insulin-Induced Hypoglycemia. Diabetes 2020; 69:228-237. [PMID: 31685528 PMCID: PMC6971486 DOI: 10.2337/db19-0438] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Accepted: 11/01/2019] [Indexed: 02/06/2023]
Abstract
Insulin-induced hypoglycemia leads to far-ranging negative consequences in patients with diabetes. Components of the counterregulatory response (CRR) system that help minimize and reverse hypoglycemia and coordination between those components are well studied but not yet fully characterized. Here, we tested the hypothesis that acyl-ghrelin, a hormone that defends against hypoglycemia in a preclinical starvation model, is permissive for the normal CRR to insulin-induced hypoglycemia. Ghrelin knockout (KO) mice and wild-type (WT) littermates underwent an insulin bolus-induced hypoglycemia test and a low-dose hyperinsulinemic-hypoglycemic clamp procedure. Clamps also were performed in ghrelin-KO mice and C57BL/6N mice administered the growth hormone secretagogue receptor agonist HM01 or vehicle. Results show that hypoglycemia, as induced by an insulin bolus, was more pronounced and prolonged in ghrelin-KO mice, supporting previous studies suggesting increased insulin sensitivity upon ghrelin deletion. Furthermore, during hyperinsulinemic-hypoglycemic clamps, ghrelin-KO mice required a 10-fold higher glucose infusion rate (GIR) and exhibited less robust corticosterone and growth hormone responses. Conversely, HM01 administration, which reduced the GIR required by ghrelin-KO mice during the clamps, increased plasma corticosterone and growth hormone. Thus, our data suggest that endogenously produced acyl-ghrelin not only influences insulin sensitivity but also is permissive for the normal CRR to insulin-induced hypoglycemia.
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Affiliation(s)
- Kripa Shankar
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX
| | - Deepali Gupta
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX
| | - Bharath K Mani
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX
| | - Brianna G Findley
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX
| | - Caleb C Lord
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX
| | - Sherri Osborne-Lawrence
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX
| | - Nathan P Metzger
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX
| | | | - Chen Liu
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX
- Department of Neuroscience, UT Southwestern Medical Center, Dallas, TX
| | - Eric D Berglund
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX
| | - Jeffrey M Zigman
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX
- Division of Endocrinology, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX
- Department of Psychiatry, UT Southwestern Medical Center, Dallas, TX
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Shankar K, Gupta D, Mani BK, Findley BG, Osborne-Lawrence S, Metzger NP, Liu C, Berglund ED, Zigman JM. Ghrelin Protects Against Insulin-Induced Hypoglycemia in a Mouse Model of Type 1 Diabetes Mellitus. Front Endocrinol (Lausanne) 2020; 11:606. [PMID: 33042003 PMCID: PMC7518392 DOI: 10.3389/fendo.2020.00606] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Accepted: 07/27/2020] [Indexed: 01/28/2023] Open
Abstract
Insulin-induced hypoglycemia is a major limiting factor in maintaining optimal blood glucose in patients with type 1 diabetes and advanced type 2 diabetes. Luckily, a counterregulatory response (1) system exists to help minimize and reverse hypoglycemia, although more studies are needed to better characterize its components. Recently, we showed that the hormone ghrelin is permissive for the normal CRR to insulin-induced hypoglycemia when assessed in mice without diabetes. Here, we tested the hypothesis that ghrelin also is protective against insulin-induced hypoglycemia in the streptozotocin (2) mouse model of type 1 diabetes. STZ-treated ghrelin-knockout (KO) (3) mice as well as STZ-treated wild-type (WT) littermates were subjected to a low-dose hyperinsulinemic-hypoglycemic clamp procedure. The STZ-treated ghrelin-KO mice required a much higher glucose infusion rate than the STZ-treated WT mice. Also, the STZ-treated ghrelin-KO mice exhibited attenuated plasma epinephrine and norepinephrine responses to the insulin-induced hypoglycemia. Taken together, our data suggest that without ghrelin, STZ-treated mice modeling type 1 diabetes are unable to mount the usual CRR to insulin-induced hypoglycemia.
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Affiliation(s)
- Kripa Shankar
- Department of Internal Medicine, Center for Hypothalamic Research, UT Southwestern Medical Center, Dallas, TX, United States
| | - Deepali Gupta
- Department of Internal Medicine, Center for Hypothalamic Research, UT Southwestern Medical Center, Dallas, TX, United States
| | - Bharath K. Mani
- Department of Internal Medicine, Center for Hypothalamic Research, UT Southwestern Medical Center, Dallas, TX, United States
| | - Brianna G. Findley
- Department of Internal Medicine, Center for Hypothalamic Research, UT Southwestern Medical Center, Dallas, TX, United States
| | - Sherri Osborne-Lawrence
- Department of Internal Medicine, Center for Hypothalamic Research, UT Southwestern Medical Center, Dallas, TX, United States
| | - Nathan P. Metzger
- Department of Internal Medicine, Center for Hypothalamic Research, UT Southwestern Medical Center, Dallas, TX, United States
| | - Chen Liu
- Department of Internal Medicine, Center for Hypothalamic Research, UT Southwestern Medical Center, Dallas, TX, United States
- Department of Neuroscience, UT Southwestern Medical Center, Dallas, TX, United States
| | - Eric D. Berglund
- Department of Internal Medicine, Center for Hypothalamic Research, UT Southwestern Medical Center, Dallas, TX, United States
| | - Jeffrey M. Zigman
- Department of Internal Medicine, Center for Hypothalamic Research, UT Southwestern Medical Center, Dallas, TX, United States
- Division of Endocrinology, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, TX, United States
- Department of Psychiatry, UT Southwestern Medical Center, Dallas, TX, United States
- *Correspondence: Jeffrey M. Zigman
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30
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Mani BK, Castorena CM, Vianna CR, Lee CE, Metzger NP, Vijayaraghavan P, Osborne-Lawrence S, Elmquist JK, Zigman JM. Combined Loss of Ghrelin Receptor and Cannabinoid CB1 Receptor in Mice Decreases Survival but does not Additively Reduce Body Weight or Eating. Neuroscience 2019; 447:53-62. [PMID: 31520709 DOI: 10.1016/j.neuroscience.2019.09.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 08/28/2019] [Accepted: 09/02/2019] [Indexed: 01/08/2023]
Abstract
Ghrelin administration increases food intake, body weight (BW), adiposity, and blood glucose. In contrast, although mouse models lacking ghrelin or its receptor (Growth Hormone Secretagogue Receptor (GHSR)) exhibit life-threatening hypoglycemia in starvation-like states, they do not exhibit appreciable reductions in food intake, BW, adiposity, blood glucose, or survival when food availability is unrestricted. This suggests the existence of a parallel neuromodulatory system that can compensate for disruptions in the ghrelin system in certain settings. Here, we hypothesized that the cannabinoid CB1 receptor (CB1R) may encode this putative redundancy, and as such, that genetic deletion of both GHSR and CB1R would exaggerate the metabolic deficits associated with deletion of GHSR alone. To test this hypothesis, we assessed food intake, BW, blood glucose, survival, and plasma acyl-ghrelin in ad libitum-fed male wild-type mice and those that genetically lack GHSR (GHSR-nulls), CB1R (CB1R-nulls), or both GHSR and CB1R (double-nulls). BW, fat mass, and lean mass were similar in GHSR-nulls and wild-types, lower in CB1R-nulls, but not further reduced in double-nulls. Food intake, plasma acyl-ghrelin, and blood glucose were similar among genotypes. Deletion of either GHSR or CB1R alone did not have a statistically-significant effect on survival, but double-nulls demonstrated a statistical trend towards decreased survival (p = 0.07). We conclude that CB1R is not responsible for the normal BW, adiposity, food intake, and blood glucose observed in GHSR-null mice in the setting of unrestricted food availability. Nor is CB1R required for plasma acyl-ghrelin secretion in that setting. However, GHSR may be protective against exaggerated mortality associated with CB1R deletion.
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Affiliation(s)
- Bharath K Mani
- Center for Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Carlos M Castorena
- Center for Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Claudia R Vianna
- Center for Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Charlotte E Lee
- Center for Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Nathan P Metzger
- Center for Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Prasanna Vijayaraghavan
- Center for Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Sherri Osborne-Lawrence
- Center for Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Joel K Elmquist
- Center for Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA; Division of Endocrinology & Metabolism, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA; Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX, USA; Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Jeffrey M Zigman
- Center for Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA; Division of Endocrinology & Metabolism, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA; Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX, USA.
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31
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Gupta D, Chuang JC, Mani BK, Shankar K, Rodriguez JA, Osborne-Lawrence S, Metzger NP, Zigman JM. β1-adrenergic receptors mediate plasma acyl-ghrelin elevation and depressive-like behavior induced by chronic psychosocial stress. Neuropsychopharmacology 2019; 44:1319-1327. [PMID: 30758330 PMCID: PMC6785135 DOI: 10.1038/s41386-019-0334-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Revised: 12/06/2018] [Accepted: 02/04/2019] [Indexed: 12/19/2022]
Abstract
The ghrelin system is a key component of the mood and metabolic responses to chronic psychosocial stress. For example, circulating acyl-ghrelin rises in several rodent and human stress models, administered acyl-ghrelin induces antidepressant-like behavioral responses in mice, and mice with deleted ghrelin receptors (GHSRs) exhibit exaggerated depressive-like behaviors, changed eating behaviors, and altered metabolism in response to chronic stress. However, the mechanisms mediating stress-induced rises in ghrelin are unknown and ghrelin's antidepressant-like efficacy in the setting of chronic stress is incompletely characterized. Here, we used a pharmacological approach in combination with a 10-day chronic social defeat stress (CSDS) model in male mice to investigate whether the sympathoadrenal system is involved in the ghrelin response to stress. We also examined the antidepressant-like efficacy of administered ghrelin and the synthetic GHSR agonist GHRP-2 during and/or after CSDS. We found that administration of the β1-adrenergic receptor (β1AR) blocker atenolol during CSDS blunts the elevation of plasma acyl-ghrelin and exaggerates depressive-like behavior. Neither acute injection of acyl-ghrelin directly following CSDS nor its chronic administration during or after CSDS nor chronic delivery of GHRP-2 during and after CSDS improved stress-induced depressive-like behavior. Thus, β1ARs drive the acyl-ghrelin response to CSDS, but supplementing the natural increases in acyl-ghrelin with exogenous acyl-ghrelin or GHSR agonist does not further enhance the antidepressant-like actions of the endogenous ghrelin system in the setting of CSDS.
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Affiliation(s)
- Deepali Gupta
- 0000 0000 9482 7121grid.267313.2Department of Internal Medicine, Division of Hypothalamic Research, UT Southwestern Medical Center, 5323 Harry Hines Blvd., MC9077, Dallas, TX 75390-9077 USA
| | - Jen-Chieh Chuang
- 0000 0000 9482 7121grid.267313.2Department of Internal Medicine, Division of Hypothalamic Research, UT Southwestern Medical Center, 5323 Harry Hines Blvd., MC9077, Dallas, TX 75390-9077 USA
| | - Bharath K. Mani
- 0000 0000 9482 7121grid.267313.2Department of Internal Medicine, Division of Hypothalamic Research, UT Southwestern Medical Center, 5323 Harry Hines Blvd., MC9077, Dallas, TX 75390-9077 USA
| | - Kripa Shankar
- 0000 0000 9482 7121grid.267313.2Department of Internal Medicine, Division of Hypothalamic Research, UT Southwestern Medical Center, 5323 Harry Hines Blvd., MC9077, Dallas, TX 75390-9077 USA
| | - Juan A. Rodriguez
- 0000 0000 9482 7121grid.267313.2Department of Internal Medicine, Division of Hypothalamic Research, UT Southwestern Medical Center, 5323 Harry Hines Blvd., MC9077, Dallas, TX 75390-9077 USA
| | - Sherri Osborne-Lawrence
- 0000 0000 9482 7121grid.267313.2Department of Internal Medicine, Division of Hypothalamic Research, UT Southwestern Medical Center, 5323 Harry Hines Blvd., MC9077, Dallas, TX 75390-9077 USA
| | - Nathan P. Metzger
- 0000 0000 9482 7121grid.267313.2Department of Internal Medicine, Division of Hypothalamic Research, UT Southwestern Medical Center, 5323 Harry Hines Blvd., MC9077, Dallas, TX 75390-9077 USA
| | - Jeffrey M. Zigman
- 0000 0000 9482 7121grid.267313.2Department of Internal Medicine, Division of Hypothalamic Research, UT Southwestern Medical Center, 5323 Harry Hines Blvd., MC9077, Dallas, TX 75390-9077 USA ,0000 0000 9482 7121grid.267313.2Department of Internal Medicine, Division of Endocrinology, UT Southwestern Medical Center, Dallas, TX USA ,0000 0000 9482 7121grid.267313.2Department of Psychiatry, UT Southwestern Medical Center, Dallas, TX USA
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Abstract
Much effort has been directed at studying the orexigenic actions of administered ghrelin and the potential effects of the endogenous ghrelin system on food intake, food reward, body weight, adiposity, and energy expenditure. Although endogenous ghrelin's actions on some of these processes remain ambiguous, its glucoregulatory actions have emerged as well-recognized features during extreme metabolic conditions. The blood glucose-raising actions of ghrelin are beneficial during starvation-like conditions, defending against life-threatening falls in blood glucose, but they are seemingly detrimental in obese states and in certain monogenic forms of diabetes, contributing to hyperglycemia. Also of interest, blood glucose negatively regulates ghrelin secretion. This article reviews the literature suggesting the existence of a blood glucose-ghrelin axis and highlights the factors that mediate the glucoregulatory actions of ghrelin, especially during metabolic extremes such as starvation and diabetes.
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Affiliation(s)
- Bharath K Mani
- Division of Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
- Division of Endocrinology and Metabolism, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Kripa Shankar
- Division of Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
- Division of Endocrinology and Metabolism, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Jeffrey M Zigman
- Division of Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
- Division of Endocrinology and Metabolism, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, Texas
- Correspondence: Jeffrey M. Zigman, MD, PhD, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas 75390. E-mail:
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33
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Rodriguez JA, Bruggeman EC, Mani BK, Osborne-Lawrence S, Lord CC, Roseman HF, Viroslav HL, Vijayaraghavan P, Metzger NP, Gupta D, Shankar K, Pietra C, Liu C, Zigman JM. Ghrelin Receptor Agonist Rescues Excess Neonatal Mortality in a Prader-Willi Syndrome Mouse Model. Endocrinology 2018; 159:4006-4022. [PMID: 30380028 PMCID: PMC6260060 DOI: 10.1210/en.2018-00801] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Accepted: 10/24/2018] [Indexed: 12/18/2022]
Abstract
In the current study, we sought to determine the significance of the ghrelin system in Prader-Willi Syndrome (PWS). PWS is characterized by hypotonia and difficulty feeding in neonates and hyperphagia and obesity beginning later in childhood. Other features include low GH, neonatal hypoglycemia, hypogonadism, and accelerated mortality. Although the hyperphagia and obesity in PWS have been attributed to elevated levels of the orexigenic hormone ghrelin, this link has never been firmly established, nor have ghrelin's potentially protective actions to increase GH secretion, blood glucose, and survival been investigated in a PWS context. In the current study, we show that placing Snord116del mice modeling PWS on ghrelin-deficient or ghrelin receptor [GH secretagogue receptor (GHSR)]-deficient backgrounds does not impact their characteristically reduced body weight, lower plasma IGF-1, delayed sexual maturation, or increased mortality in the period prior to weaning. However, blood glucose was further reduced in male Snord116del pups on a ghrelin-deficient background, and percentage body weight gain and percentage fat mass were further reduced in male Snord116del pups on a GHSR-deficient background. Strikingly, 2 weeks of daily administration of the GHSR agonist HM01 to Snord116del neonates markedly improved survival, resulting in a nearly complete rescue of the excess mortality owing to loss of the paternal Snord116 gene. These data support further exploration of the therapeutic potential of GHSR agonist administration in limiting PWS mortality, especially during the period characterized by failure to thrive.
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Affiliation(s)
- Juan A Rodriguez
- Division of Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas
| | - Emily C Bruggeman
- Division of Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas
| | - Bharath K Mani
- Division of Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas
| | - Sherri Osborne-Lawrence
- Division of Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas
| | - Caleb C Lord
- Division of Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas
| | - Henry F Roseman
- Division of Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas
| | - Hannah L Viroslav
- Division of Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas
| | - Prasanna Vijayaraghavan
- Division of Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas
| | - Nathan P Metzger
- Division of Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas
| | - Deepali Gupta
- Division of Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas
| | - Kripa Shankar
- Division of Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas
| | | | - Chen Liu
- Division of Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas
- Department of Neuroscience, UT Southwestern Medical Center, Dallas, Texas
| | - Jeffrey M Zigman
- Division of Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas
- Division of Endocrinology, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas
- Department of Psychiatry, UT Southwestern Medical Center, Dallas, Texas
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Cornejo MP, De Francesco PN, García Romero G, Portiansky EL, Zigman JM, Reynaldo M, Perello M. Ghrelin receptor signaling targets segregated clusters of neurons within the nucleus of the solitary tract. Brain Struct Funct 2018; 223:3133-3147. [DOI: 10.1007/s00429-018-1682-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Accepted: 05/09/2018] [Indexed: 11/29/2022]
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35
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Mani BK, Castorena CM, Osborne-Lawrence S, Vijayaraghavan P, Metzger NP, Elmquist JK, Zigman JM. Ghrelin mediates exercise endurance and the feeding response post-exercise. Mol Metab 2018; 9:114-130. [PMID: 29396372 PMCID: PMC5870098 DOI: 10.1016/j.molmet.2018.01.006] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Revised: 01/09/2018] [Accepted: 01/12/2018] [Indexed: 12/19/2022] Open
Abstract
Objective Exercise training has several well-established health benefits, including many related to body weight, appetite control, and blood glucose homeostasis. However, the molecular mechanisms and, in particular, the hormonal systems that mediate and integrate these beneficial effects are poorly understood. In the current study, we aimed to investigate the role of the hormone ghrelin and its receptor, the growth hormone secretagogue receptor (GHSR; ghrelin receptor), in mediating the effects of exercise on food intake and blood glucose following exercise as well as in regulating exercise endurance capacity. Methods We used two mouse models of treadmill running to characterize the changes in plasma ghrelin with exercise. We also assessed the role of the ghrelin system to influence food intake and blood glucose after exercise, exercise endurance, and parameters potentially linked to responses to exercise. Mice lacking GHSRs (GHSR-null mice) and wild-type littermates were studied. Results An acute bout of exercise transiently elevated plasma acyl-ghrelin. Without the action of this increased ghrelin on GHSRs (as in GHSR-null mice), high intensity interval exercise markedly reduced food intake compared to control mice. The effect of exercise to acutely raise blood glucose remained unmodified in GHSR-null mice. Exercise-induced increases in plasma ghrelin positively correlated with endurance capacity, and time to exhaustion was reduced in GHSR-null mice as compared to wild-type littermates. In an effort to mechanistically explain their reduced exercise endurance, exercised GHSR-null mice exhibited an abrogated sympathoadrenal response, lower overall insulin-like growth factor-1 levels, and altered glycogen utilization. Conclusions Exercise transiently increases plasma ghrelin. GHSR-null mice exhibit decreased food intake following high intensity interval exercise and decreased endurance when submitted to an exercise endurance protocol. These data suggest that an intact ghrelin system limits the capacity of exercise to restrict food intake following exercise, although it enhances exercise endurance. High intensity exercise transiently increases plasma ghrelin. Without ghrelin action on its receptors (growth hormone secretagogue receptors), exercise markedly reduces food intake. An intact ghrelin system enhances exercise endurance.
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Affiliation(s)
- Bharath K Mani
- Division of Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Carlos M Castorena
- Division of Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Sherri Osborne-Lawrence
- Division of Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Prasanna Vijayaraghavan
- Division of Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Nathan P Metzger
- Division of Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Joel K Elmquist
- Division of Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA; Division of Endocrinology & Metabolism, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA; Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX, USA; Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Jeffrey M Zigman
- Division of Hypothalamic Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA; Division of Endocrinology & Metabolism, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA; Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX, USA.
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Abstract
Hyperphagia and obesity are the best-known manifestations of Prader-Willi syndrome (PWS) and are responsible for most of the overall morbidity and mortality associated with the disease. Yet these PWS symptoms remain poorly understood and without effective pharmacologic therapies. Mouse models attempting to recapitulate both the genetic alterations and marked hyperphagia plus obesity of PWS have been enigmatic, leading to skepticism about the use of mouse models to investigate PWS. In this issue of the JCI, Polex-Wolf and colleagues challenge the skeptics by successfully inducing hyperphagia following bilateral mediobasal hypothalamic deletion of the Snord116 gene from adult mice. Obesity also resulted, although only in a subset of mice. While this approach represents an exciting advance, highlighting a pathologic effect of loss of mediobasal hypothalamic Snord116 expression on the development of PWS's hallmark symptoms, the variability in the body-weight and body composition responses to this site-selective gene deletion raises several questions.
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Affiliation(s)
- Juan A Rodriguez
- Division of Hypothalamic Research, Department of Internal Medicine
| | - Jeffrey M Zigman
- Division of Hypothalamic Research, Department of Internal Medicine.,Division of Endocrinology and Metabolism, Department of Internal Medicine, and.,Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, Texas, USA
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37
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Abstract
Ghrelin administration induces food intake and body weight gain. Based on these actions, the ghrelin system was initially proposed as an antiobesity target. Subsequent studies using genetic mouse models have raised doubts about the role of the endogenous ghrelin system in mediating body weight homeostasis or obesity. However, this is not to say that the endogenous ghrelin system is not important metabolically or otherwise. Here we review an emerging concept in which the endogenous ghrelin system serves an essential function during extreme nutritional and psychological challenges to defend blood glucose, protect body weight, avoid exaggerated depression, and ultimately allow survival.
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Affiliation(s)
- Bharath K Mani
- Divisions of Hypothalamic Research and Endocrinology, Department of Internal Medicine, and Department of Psychiatry, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390-9077, USA
| | - Jeffrey M Zigman
- Divisions of Hypothalamic Research and Endocrinology, Department of Internal Medicine, and Department of Psychiatry, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390-9077, USA.
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38
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Mani BK, Uchida A, Lee Y, Osborne-Lawrence S, Charron MJ, Unger RH, Berglund ED, Zigman JM. Hypoglycemic Effect of Combined Ghrelin and Glucagon Receptor Blockade. Diabetes 2017; 66:1847-1857. [PMID: 28487437 PMCID: PMC5482080 DOI: 10.2337/db16-1303] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Accepted: 04/19/2017] [Indexed: 12/18/2022]
Abstract
Glucagon receptor (GcgR) blockade has been proposed as an alternative to insulin monotherapy for treating type 1 diabetes since deletion or inhibition of GcgRs corrects hyperglycemia in models of diabetes. The factors regulating glycemia in a setting devoid of insulin and glucagon function remain unclear but may include the hormone ghrelin. Not only is ghrelin release controlled by glucose but also ghrelin has many actions that can raise or reduce falls in blood glucose level. Here, we tested the hypothesis that ghrelin rises to prevent hypoglycemia in the absence of glucagon function. Both GcgR knockout (Gcgr-/-) mice and db/db mice that were administered GcgR monoclonal antibody displayed lower blood glucose levels accompanied by elevated plasma ghrelin levels. Although treatment with the pancreatic β-cell toxin streptozotocin induced hyperglycemia and raised plasma ghrelin levels in wild-type mice, hyperglycemia was averted in similarly treated Gcgr-/- mice and the plasma ghrelin level was further increased. Notably, administration of a ghrelin receptor antagonist further reduced blood glucose levels into the markedly hypoglycemic range in overnight-fasted, streptozotocin-treated Gcgr-/- mice. A lowered blood glucose level also was observed in overnight-fasted, streptozotocin-treated ghrelin receptor-null mice that were administered GcgR monoclonal antibody. These data suggest that when glucagon activity is blocked in the setting of type 1 diabetes, the plasma ghrelin level rises, preventing hypoglycemia.
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MESH Headings
- Animals
- Antibodies, Monoclonal/pharmacology
- Atenolol/pharmacology
- Blood Glucose/drug effects
- Blood Glucose/metabolism
- Cells, Cultured
- Diabetes Mellitus, Experimental/genetics
- Diabetes Mellitus, Experimental/metabolism
- Diabetes Mellitus, Type 1/genetics
- Diabetes Mellitus, Type 1/metabolism
- Gastric Mucosa/metabolism
- Ghrelin/metabolism
- Immunohistochemistry
- Insulin/metabolism
- Mice
- Mice, Knockout
- Oligopeptides/pharmacology
- Real-Time Polymerase Chain Reaction
- Receptors, Ghrelin/antagonists & inhibitors
- Receptors, Glucagon/antagonists & inhibitors
- Receptors, Glucagon/genetics
- Receptors, Leptin/genetics
- Sympatholytics/pharmacology
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Affiliation(s)
- Bharath K Mani
- Divisions of Hypothalamic Research and Endocrinology, Department of Internal Medicine and Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX
| | - Aki Uchida
- Advanced Imaging Center and Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX
| | - Young Lee
- Touchstone Diabetes Center, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX
| | - Sherri Osborne-Lawrence
- Divisions of Hypothalamic Research and Endocrinology, Department of Internal Medicine and Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX
| | - Maureen J Charron
- Departments of Biochemistry, Obstetrics and Gynecology and Woman's Health, and Medicine, Albert Einstein College of Medicine, Bronx, NY
| | - Roger H Unger
- Touchstone Diabetes Center, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX
| | - Eric D Berglund
- Advanced Imaging Center and Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX
| | - Jeffrey M Zigman
- Divisions of Hypothalamic Research and Endocrinology, Department of Internal Medicine and Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX
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Cabral A, Cornejo MP, Fernandez G, De Francesco PN, Garcia-Romero G, Uriarte M, Zigman JM, Portiansky E, Reynaldo M, Perello M. Circulating Ghrelin Acts on GABA Neurons of the Area Postrema and Mediates Gastric Emptying in Male Mice. Endocrinology 2017; 158:1436-1449. [PMID: 28204197 DOI: 10.1210/en.2016-1815] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Accepted: 02/10/2017] [Indexed: 11/19/2022]
Abstract
Ghrelin is known to act on the area postrema (AP), a sensory circumventricular organ located in the medulla oblongata that regulates a variety of important physiological functions. However, the neuronal targets of ghrelin in the AP and their potential role are currently unknown. In this study, we used wild-type and genetically modified mice to gain insights into the neurons of the AP expressing the ghrelin receptor [growth hormone secretagogue receptor (GHSR)] and their role. We show that circulating ghrelin mainly accesses the AP but not to the adjacent nucleus of the solitary tract. Also, we show that both peripheral administration of ghrelin and fasting induce an increase of c-Fos, a marker of neuronal activation, in GHSR-expressing neurons of the AP, and that GHSR expression is necessary for the fasting-induced activation of AP neurons. Additionally, we show that ghrelin-sensitive neurons of the AP are mainly γ-aminobutyric acid (GABA)ergic, and that an intact AP is required for ghrelin-induced gastric emptying. Overall, we show that the capacity of circulating ghrelin to acutely induce gastric emptying in mice requires the integrity of the AP, which contains a population of GABA neurons that are a target of plasma ghrelin.
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Affiliation(s)
- Agustina Cabral
- Laboratorio de Neurofisiología del Instituto Multidisciplinario de Biología Celular, Consejo Nacional de Investigaciones Científicas y Técnicas de Argentina, Universidad Nacional de La Plata y Comisión de Investigaciones Científicas-Provincia de Buenas Aires, 1900 La Plata, Buenos Aires, Argentina
| | - María P Cornejo
- Laboratorio de Neurofisiología del Instituto Multidisciplinario de Biología Celular, Consejo Nacional de Investigaciones Científicas y Técnicas de Argentina, Universidad Nacional de La Plata y Comisión de Investigaciones Científicas-Provincia de Buenas Aires, 1900 La Plata, Buenos Aires, Argentina
| | - Gimena Fernandez
- Laboratorio de Neurofisiología del Instituto Multidisciplinario de Biología Celular, Consejo Nacional de Investigaciones Científicas y Técnicas de Argentina, Universidad Nacional de La Plata y Comisión de Investigaciones Científicas-Provincia de Buenas Aires, 1900 La Plata, Buenos Aires, Argentina
| | - Pablo N De Francesco
- Laboratorio de Neurofisiología del Instituto Multidisciplinario de Biología Celular, Consejo Nacional de Investigaciones Científicas y Técnicas de Argentina, Universidad Nacional de La Plata y Comisión de Investigaciones Científicas-Provincia de Buenas Aires, 1900 La Plata, Buenos Aires, Argentina
| | - Guadalupe Garcia-Romero
- Laboratorio de Neurofisiología del Instituto Multidisciplinario de Biología Celular, Consejo Nacional de Investigaciones Científicas y Técnicas de Argentina, Universidad Nacional de La Plata y Comisión de Investigaciones Científicas-Provincia de Buenas Aires, 1900 La Plata, Buenos Aires, Argentina
| | - Maia Uriarte
- Laboratorio de Neurofisiología del Instituto Multidisciplinario de Biología Celular, Consejo Nacional de Investigaciones Científicas y Técnicas de Argentina, Universidad Nacional de La Plata y Comisión de Investigaciones Científicas-Provincia de Buenas Aires, 1900 La Plata, Buenos Aires, Argentina
| | - Jeffrey M Zigman
- Divisions of Hypothalamic Research and Endocrinology, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas 75390
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, Texas 75390
| | - Enrique Portiansky
- Laboratorio de Análisis de Imágenes, Facultad de Ciencias Veterinarias, Universidad Nacional de La Plata y Consejo Nacional de Investigaciones Científicas y Técnicas de Argentina, 1900 La Plata, Buenos Aires, Argentina
| | - Mirta Reynaldo
- Laboratorio de Neurofisiología del Instituto Multidisciplinario de Biología Celular, Consejo Nacional de Investigaciones Científicas y Técnicas de Argentina, Universidad Nacional de La Plata y Comisión de Investigaciones Científicas-Provincia de Buenas Aires, 1900 La Plata, Buenos Aires, Argentina
| | - Mario Perello
- Laboratorio de Neurofisiología del Instituto Multidisciplinario de Biología Celular, Consejo Nacional de Investigaciones Científicas y Técnicas de Argentina, Universidad Nacional de La Plata y Comisión de Investigaciones Científicas-Provincia de Buenas Aires, 1900 La Plata, Buenos Aires, Argentina
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Chacrabati R, Gong Z, Ikenoya C, Kondo D, Zigman JM, Sakai T, Sakata I. The effect of glutamate on ghrelin release in mice. Cell Biol Int 2017; 41:320-327. [DOI: 10.1002/cbin.10728] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Accepted: 12/30/2016] [Indexed: 12/14/2022]
Affiliation(s)
- Rakhi Chacrabati
- Area of Regulatory Biology; Division of Life Science; Graduate School of Science and Engineering; Saitama University; 255 Shimo-ohkubo Sakuraku Saitama 338-8570 Japan
| | - Zhi Gong
- Area of Regulatory Biology; Division of Life Science; Graduate School of Science and Engineering; Saitama University; 255 Shimo-ohkubo Sakuraku Saitama 338-8570 Japan
| | - Chika Ikenoya
- Area of Regulatory Biology; Division of Life Science; Graduate School of Science and Engineering; Saitama University; 255 Shimo-ohkubo Sakuraku Saitama 338-8570 Japan
| | - Daisuke Kondo
- Area of Regulatory Biology; Division of Life Science; Graduate School of Science and Engineering; Saitama University; 255 Shimo-ohkubo Sakuraku Saitama 338-8570 Japan
| | - Jeffrey M. Zigman
- Departments of Internal Medicine (Divisions of Hypothalamic Research and Endocrinology & Metabolism) and Psychiatry; University of Texas Southwestern Medical Center; 5323 Harry Hines Blvd Dallas TX 75390-9077 USA
| | - Takafumi Sakai
- Area of Life-NanoBio, Division of Strategy, Graduate School of Science and Engineering; Saitama University; 255 Shimo-ohkubo Sakuraku Saitama 338-8570 Japan
| | - Ichiro Sakata
- Area of Regulatory Biology; Division of Life Science; Graduate School of Science and Engineering; Saitama University; 255 Shimo-ohkubo Sakuraku Saitama 338-8570 Japan
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Mani BK, Osborne-Lawrence S, Vijayaraghavan P, Hepler C, Zigman JM. β1-Adrenergic receptor deficiency in ghrelin-expressing cells causes hypoglycemia in susceptible individuals. J Clin Invest 2016; 126:3467-78. [PMID: 27548523 DOI: 10.1172/jci86270] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2015] [Accepted: 07/07/2016] [Indexed: 01/06/2023] Open
Abstract
Ghrelin is an orexigenic gastric peptide hormone secreted when caloric intake is limited. Ghrelin also regulates blood glucose, as emphasized by the hypoglycemia that is induced by caloric restriction in mouse models of deficient ghrelin signaling. Here, we hypothesized that activation of β1-adrenergic receptors (β1ARs) localized to ghrelin cells is required for caloric restriction-associated ghrelin release and the ensuing protective glucoregulatory response. In mice lacking the β1AR specifically in ghrelin-expressing cells, ghrelin secretion was markedly blunted, resulting in profound hypoglycemia and prevalent mortality upon severe caloric restriction. Replacement of ghrelin blocked the effects of caloric restriction in β1AR-deficient mice. We also determined that treating calorically restricted juvenile WT mice with beta blockers led to reduced plasma ghrelin and hypoglycemia, the latter of which is similar to the life-threatening, fasting-induced hypoglycemia observed in infants treated with beta blockers. These findings highlight the critical functions of ghrelin in preventing hypoglycemia and promoting survival during severe caloric restriction and the requirement for ghrelin cell-expressed β1ARs in these processes. Moreover, these results indicate a potential role for ghrelin in mediating beta blocker-associated hypoglycemia in susceptible individuals, such as young children.
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Zigman JM, Bouret SG, Andrews ZB. Correction to 'Obesity Impairs the Action of the Neuroendocrine Ghrelin System': [Trends in Endocrinology and Metabolism, 27 (2016) 54-63]. Trends Endocrinol Metab 2016; 27:348. [PMID: 27106266 DOI: 10.1016/j.tem.2016.02.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Affiliation(s)
- Jeffrey M Zigman
- Departments of Internal Medicine (Divisions of Hypothalamic Research and Endocrinology and Metabolism) and Psychiatry, The University of Texas Southwestern Medical Center, Dallas, TX, 75390-9077, USA.
| | - Sebastien G Bouret
- The Saban Research Institute, Developmental Neuroscience Program, Children's Hospital Los Angeles, University of Southern California, Los Angeles, CA 90027, USA; Inserm, Jean-Pierre Aubert Research Center, U1172, University Lille 2, Lille, 59045, France
| | - Zane B Andrews
- Metabolic Disease and Obesity Theme, Biomedicine Discovery Institute, Department of Physiology, Monash University, Clayton, Victoria 3183, Australia.
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Cabral A, Portiansky E, Sánchez-Jaramillo E, Zigman JM, Perello M. Ghrelin activates hypophysiotropic corticotropin-releasing factor neurons independently of the arcuate nucleus. Psychoneuroendocrinology 2016; 67:27-39. [PMID: 26874559 PMCID: PMC4808343 DOI: 10.1016/j.psyneuen.2016.01.027] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Revised: 01/28/2016] [Accepted: 01/29/2016] [Indexed: 10/22/2022]
Abstract
Previous work has established that the hormone ghrelin engages the hypothalamic-pituitary-adrenal neuroendocrine axis via activation of corticotropin-releasing factor (CRF) neurons of the hypothalamic paraventricular nucleus (PVN). The neuronal circuitry that mediates this effect of ghrelin is currently unknown. Here, we show that ghrelin-induced activation of PVN CRF neurons involved inhibition of γ-aminobutyric acid (GABA) inputs, likely via ghrelin binding sites that were localized at GABAergic terminals within the PVN. While ghrelin activated PVN CRF neurons in the presence of neuropeptide Y (NPY) receptor antagonists or in arcuate nucleus (ARC)-ablated mice, it failed to do it so in mice with ghrelin receptor expression limited to ARC agouti gene related protein (AgRP)/NPY neurons. These data support the notion that ghrelin activates PVN CRF neurons via inhibition of local GABAergic tone, in an ARC-independent manner. Furthermore, these data suggest that the neuronal circuits mediating ghrelin's orexigenic action vs. its role as a stress signal are anatomically dissociated.
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Affiliation(s)
| | | | | | | | - Mario Perello
- Laboratory of Neurophysiology, Multidisciplinary Institute of Cell Biology [IMBICE-Argentine Research Council (CONICET) and Scientific Research Commission, Province of Buenos Aires (CIC-PBA)], La Plata, Buenos Aires, Argentina.
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44
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Puzziferri N, Zigman JM, Thomas BP, Mihalakos P, Gallagher R, Lutter M, Carmody T, Lu H, Tamminga CA. Brain imaging demonstrates a reduced neural impact of eating in obesity. Obesity (Silver Spring) 2016; 24:829-36. [PMID: 26891710 PMCID: PMC4814322 DOI: 10.1002/oby.21424] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2015] [Revised: 11/12/2015] [Accepted: 11/14/2015] [Indexed: 12/12/2022]
Abstract
OBJECTIVE This study investigated functional brain response differences to food in women with BMI either <25 kg/m(2) (lean) or >35 kg/m(2) (severe obesity). DESIGN AND METHODS Thirty women, 18-65 years old, from academic medical centers participated. Baseline brain perfusion was measured with arterial spin labeling. Brain activity was measured via blood-oxygen-level-dependent functional magnetic resonance imaging in response to food cues, and appeal to cues was rated. Subjective hunger/fullness was reported pre- and post-imaging. After a standard meal, measures were repeated. RESULTS When fasting, brain perfusion did not differ significantly between groups; and both groups showed significantly increased activity in the neo- and limbic cortices and midbrain compared with baseline (P < 0.05, family-wise-error whole-brain corrected). Once fed, the lean group showed significantly decreased activation in these areas, especially the limbic cortex, whereas the group with severe obesity showed no such decreases (P < 0.05, family-wise-error whole-brain corrected). After eating, appeal ratings of food decreased only in lean women. Within groups, hunger decreased (P < 0.001) and fullness increased (P < 0.001) fasted to fed. CONCLUSIONS While fasting, brain response to food cues in women did not differ significantly despite BMI. After eating, brain activity quickly diminished in lean women but remained elevated in women with severe obesity. These brain activation findings confirm previous studies.
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Affiliation(s)
- Nancy Puzziferri
- Department of Surgery, University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Department of Surgery, Veterans Administration North Texas Health Care System, Dallas, Texas, USA
- Department of Clinical Sciences, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Jeffrey M Zigman
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Binu P Thomas
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Advanced Imaging Research Center and the Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Perry Mihalakos
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Ryan Gallagher
- Department of Surgery, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Michael Lutter
- Department of Psychiatry, University of Iowa, Carver College of Medicine, Iowa City, Iowa, USA
| | - Thomas Carmody
- Department of Clinical Sciences, University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Hanzhang Lu
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, Texas, USA
- Advanced Imaging Research Center and the Department of Radiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Carol A Tamminga
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, Texas, USA
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Zigman JM, Bouret SG, Andrews ZB. Obesity Impairs the Action of the Neuroendocrine Ghrelin System. Trends Endocrinol Metab 2016; 27:54-63. [PMID: 26542050 PMCID: PMC4814209 DOI: 10.1016/j.tem.2015.09.010] [Citation(s) in RCA: 93] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Revised: 09/22/2015] [Accepted: 09/28/2015] [Indexed: 01/08/2023]
Abstract
Ghrelin is a metabolic hormone that promotes energy conservation by regulating appetite and energy expenditure. Although some studies suggest that antagonizing ghrelin function attenuates body weight gain and glucose intolerance on a high calorie diet, there is little information about the metabolic actions of ghrelin in the obese state. In this review, we discuss the novel concept of obesity-induced central ghrelin resistance in neural circuits regulating behavior, and impaired ghrelin secretion from the stomach. Interestingly, weight loss restores ghrelin secretion and function, and we hypothesize that ghrelin resistance is a mechanism designed to protect a higher body weight set-point established during times of food availability, to maximize energy reserves during a time of food scarcity.
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Affiliation(s)
- Jeffrey M Zigman
- Departments of Internal Medicine (Divisions of Hypothalamic Research and Endocrinology and Metabolism) and Psychiatry, The University of Texas Southwestern Medical Center, Dallas, TX, 75390-9077, USA.
| | - Sebastien G Bouret
- The Saban Research Institute, Developmental Neuroscience Program, Children's Hospital Los Angeles, University of Southern California, Los Angeles, CA 90027, USA; Inserm, Jean-Pierre Aubert Research Center, U1172, University Lille 2, Lille, 59045, France
| | - Zane B Andrews
- Metabolic Disease and Obesity Theme, Biomedicine Discovery Institute, Department of Physiology, Monash University, Clayton, Victoria 3183, Australia
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46
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Affiliation(s)
- Bharath K Mani
- Divisions of Hypothalamic Research and Endocrinology and Metabolism, Department of Internal Medicine and Department of Psychiatry, The University of Texas Southwestern Medical Center, Dallas, Texas 75390-9077
| | - Jeffrey M Zigman
- Divisions of Hypothalamic Research and Endocrinology and Metabolism, Department of Internal Medicine and Department of Psychiatry, The University of Texas Southwestern Medical Center, Dallas, Texas 75390-9077
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Engelstoft MS, Lund ML, Grunddal KV, Egerod KL, Osborne-Lawrence S, Poulsen SS, Zigman JM, Schwartz TW. Research Resource: A Chromogranin A Reporter for Serotonin and Histamine Secreting Enteroendocrine Cells. Mol Endocrinol 2015; 29:1658-71. [PMID: 26352512 DOI: 10.1210/me.2015-1106] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Chromogranin A (ChgA) is an acidic protein found in large dense-core secretory vesicles and generally considered to be expressed in all enteroendocrine cells of the gastrointestinal (GI) tract. Here, we characterize a novel reporter mouse for ChgA, ChgA-humanized Renilla reniformis (hr)GFP. The hrGFP reporter was found in the monoamine-storing chromaffin cells of the adrenal medulla, where ChgA was originally discovered. hrGFP also was expressed in enteroendocrine cells throughout the GI tract, faithfully after the expression of ChgA, as characterized by immunohistochemistry and quantitative PCR analysis of fluorescence-activated cell sorting-purified cells, although the expression in the small intestine was weak compared with that of the stomach and colon. In the stomach, hrGFP was highly expressed in almost all histamine-storing enterochromaffin (EC)-like cells, at a lower level in the majority of serotonin-storing EC cells and ghrelin cells, in a small fraction of somatostatin cells, but was absent from gastrin cells. In the small intestine, the hrGFP reporter was selectively, but weakly expressed in EC cells, although not in any peptide-storing enteroendocrine cells. In the colon, hrGFP was exclusively expressed in EC cells but absent from the peptide-storing enteroendocrine cells. In contrast, in the pancreas, hrGFP was expressed in β-cells, α-cells, and a fraction of pancreatic polypeptide cells. It is concluded that ChgA-hrGFP in the GI tract functions as an effective reporter, particularly for the large populations of still poorly characterized monoamine-storing enteroendocrine cells. Furthermore, our findings substantiate the potential function of ChgA as a monoamine-binding protein that facilitates the regulated endocrine secretion of large amounts of monoamines from enteroendocrine cells.
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Affiliation(s)
- Maja S Engelstoft
- Novo Nordisk Foundation Center for Basic Metabolic Research (M.S.E., M.L.L., K.V.G., K.L.E., T.W.S.), Section for Metabolic Receptology, and Laboratory for Molecular Pharmacology (M.S.E., M.L.L., K.V.G., K.L.E., T.W.S.), Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, and Department of Biomedical Sciences (S.S.P.), Endocrinology Research Section, University of Copenhagen, Copenhagen DK-2200, Denmark; Danish Diabetes Academy (M.S.E.), Odense, Denmark; and Division of Hypothalamic Research (S.O.-L., J.M.Z.), Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, Texas 75390
| | - Mari L Lund
- Novo Nordisk Foundation Center for Basic Metabolic Research (M.S.E., M.L.L., K.V.G., K.L.E., T.W.S.), Section for Metabolic Receptology, and Laboratory for Molecular Pharmacology (M.S.E., M.L.L., K.V.G., K.L.E., T.W.S.), Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, and Department of Biomedical Sciences (S.S.P.), Endocrinology Research Section, University of Copenhagen, Copenhagen DK-2200, Denmark; Danish Diabetes Academy (M.S.E.), Odense, Denmark; and Division of Hypothalamic Research (S.O.-L., J.M.Z.), Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, Texas 75390
| | - Kaare V Grunddal
- Novo Nordisk Foundation Center for Basic Metabolic Research (M.S.E., M.L.L., K.V.G., K.L.E., T.W.S.), Section for Metabolic Receptology, and Laboratory for Molecular Pharmacology (M.S.E., M.L.L., K.V.G., K.L.E., T.W.S.), Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, and Department of Biomedical Sciences (S.S.P.), Endocrinology Research Section, University of Copenhagen, Copenhagen DK-2200, Denmark; Danish Diabetes Academy (M.S.E.), Odense, Denmark; and Division of Hypothalamic Research (S.O.-L., J.M.Z.), Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, Texas 75390
| | - Kristoffer L Egerod
- Novo Nordisk Foundation Center for Basic Metabolic Research (M.S.E., M.L.L., K.V.G., K.L.E., T.W.S.), Section for Metabolic Receptology, and Laboratory for Molecular Pharmacology (M.S.E., M.L.L., K.V.G., K.L.E., T.W.S.), Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, and Department of Biomedical Sciences (S.S.P.), Endocrinology Research Section, University of Copenhagen, Copenhagen DK-2200, Denmark; Danish Diabetes Academy (M.S.E.), Odense, Denmark; and Division of Hypothalamic Research (S.O.-L., J.M.Z.), Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, Texas 75390
| | - Sherri Osborne-Lawrence
- Novo Nordisk Foundation Center for Basic Metabolic Research (M.S.E., M.L.L., K.V.G., K.L.E., T.W.S.), Section for Metabolic Receptology, and Laboratory for Molecular Pharmacology (M.S.E., M.L.L., K.V.G., K.L.E., T.W.S.), Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, and Department of Biomedical Sciences (S.S.P.), Endocrinology Research Section, University of Copenhagen, Copenhagen DK-2200, Denmark; Danish Diabetes Academy (M.S.E.), Odense, Denmark; and Division of Hypothalamic Research (S.O.-L., J.M.Z.), Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, Texas 75390
| | - Steen Seier Poulsen
- Novo Nordisk Foundation Center for Basic Metabolic Research (M.S.E., M.L.L., K.V.G., K.L.E., T.W.S.), Section for Metabolic Receptology, and Laboratory for Molecular Pharmacology (M.S.E., M.L.L., K.V.G., K.L.E., T.W.S.), Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, and Department of Biomedical Sciences (S.S.P.), Endocrinology Research Section, University of Copenhagen, Copenhagen DK-2200, Denmark; Danish Diabetes Academy (M.S.E.), Odense, Denmark; and Division of Hypothalamic Research (S.O.-L., J.M.Z.), Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, Texas 75390
| | - Jeffrey M Zigman
- Novo Nordisk Foundation Center for Basic Metabolic Research (M.S.E., M.L.L., K.V.G., K.L.E., T.W.S.), Section for Metabolic Receptology, and Laboratory for Molecular Pharmacology (M.S.E., M.L.L., K.V.G., K.L.E., T.W.S.), Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, and Department of Biomedical Sciences (S.S.P.), Endocrinology Research Section, University of Copenhagen, Copenhagen DK-2200, Denmark; Danish Diabetes Academy (M.S.E.), Odense, Denmark; and Division of Hypothalamic Research (S.O.-L., J.M.Z.), Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, Texas 75390
| | - Thue W Schwartz
- Novo Nordisk Foundation Center for Basic Metabolic Research (M.S.E., M.L.L., K.V.G., K.L.E., T.W.S.), Section for Metabolic Receptology, and Laboratory for Molecular Pharmacology (M.S.E., M.L.L., K.V.G., K.L.E., T.W.S.), Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, and Department of Biomedical Sciences (S.S.P.), Endocrinology Research Section, University of Copenhagen, Copenhagen DK-2200, Denmark; Danish Diabetes Academy (M.S.E.), Odense, Denmark; and Division of Hypothalamic Research (S.O.-L., J.M.Z.), Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, Texas 75390
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Müller TD, Nogueiras R, Andermann ML, Andrews ZB, Anker SD, Argente J, Batterham RL, Benoit SC, Bowers CY, Broglio F, Casanueva FF, D'Alessio D, Depoortere I, Geliebter A, Ghigo E, Cole PA, Cowley M, Cummings DE, Dagher A, Diano S, Dickson SL, Diéguez C, Granata R, Grill HJ, Grove K, Habegger KM, Heppner K, Heiman ML, Holsen L, Holst B, Inui A, Jansson JO, Kirchner H, Korbonits M, Laferrère B, LeRoux CW, Lopez M, Morin S, Nakazato M, Nass R, Perez-Tilve D, Pfluger PT, Schwartz TW, Seeley RJ, Sleeman M, Sun Y, Sussel L, Tong J, Thorner MO, van der Lely AJ, van der Ploeg LHT, Zigman JM, Kojima M, Kangawa K, Smith RG, Horvath T, Tschöp MH. Ghrelin. Mol Metab 2015; 4:437-60. [PMID: 26042199 PMCID: PMC4443295 DOI: 10.1016/j.molmet.2015.03.005] [Citation(s) in RCA: 680] [Impact Index Per Article: 75.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Revised: 03/11/2015] [Accepted: 03/11/2015] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND The gastrointestinal peptide hormone ghrelin was discovered in 1999 as the endogenous ligand of the growth hormone secretagogue receptor. Increasing evidence supports more complicated and nuanced roles for the hormone, which go beyond the regulation of systemic energy metabolism. SCOPE OF REVIEW In this review, we discuss the diverse biological functions of ghrelin, the regulation of its secretion, and address questions that still remain 15 years after its discovery. MAJOR CONCLUSIONS In recent years, ghrelin has been found to have a plethora of central and peripheral actions in distinct areas including learning and memory, gut motility and gastric acid secretion, sleep/wake rhythm, reward seeking behavior, taste sensation and glucose metabolism.
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Affiliation(s)
- T D Müller
- Institute for Diabetes and Obesity, Helmholtz Zentrum München, München, Germany
| | - R Nogueiras
- Department of Physiology, Centro de Investigación en Medicina Molecular y Enfermedades Crónicas, University of Santiago de Compostela (CIMUS)-Instituto de Investigación Sanitaria (IDIS)-CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), Santiago de Compostela, Spain
| | - M L Andermann
- Division of Endocrinology, Department of Medicine, Beth Israel Deaconess Medical Center, Boston, MA, USA
| | - Z B Andrews
- Department of Physiology, Faculty of Medicine, Monash University, Melbourne, Victoria, Australia
| | - S D Anker
- Applied Cachexia Research, Department of Cardiology, Charité Universitätsmedizin Berlin, Germany
| | - J Argente
- Department of Pediatrics and Pediatric Endocrinology, Hospital Infantil Universitario Niño Jesús, Instituto de Investigación La Princesa, Madrid, Spain ; Department of Pediatrics, Universidad Autónoma de Madrid and CIBER Fisiopatología de la obesidad y nutrición, Instituto de Salud Carlos III, Madrid, Spain
| | - R L Batterham
- Centre for Obesity Research, University College London, London, United Kingdom
| | - S C Benoit
- Metabolic Disease Institute, Division of Endocrinology, Department of Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - C Y Bowers
- Tulane University Health Sciences Center, Endocrinology and Metabolism Section, Peptide Research Section, New Orleans, LA, USA
| | - F Broglio
- Division of Endocrinology, Diabetes and Metabolism, Dept. of Medical Sciences, University of Torino, Torino, Italy
| | - F F Casanueva
- Department of Medicine, Santiago de Compostela University, Complejo Hospitalario Universitario de Santiago (CHUS), CIBER de Fisiopatologia Obesidad y Nutricion (CB06/03), Instituto Salud Carlos III, Santiago de Compostela, Spain
| | - D D'Alessio
- Duke Molecular Physiology Institute, Duke University, Durham, NC, USA
| | - I Depoortere
- Translational Research Center for Gastrointestinal Disorders, University of Leuven, Leuven, Belgium
| | - A Geliebter
- New York Obesity Nutrition Research Center, Department of Medicine, St Luke's-Roosevelt Hospital Center, Columbia University College of Physicians and Surgeons, New York, NY, USA
| | - E Ghigo
- Department of Pharmacology & Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - P A Cole
- Monash Obesity & Diabetes Institute, Monash University, Clayton, Victoria, Australia
| | - M Cowley
- Department of Physiology, Faculty of Medicine, Monash University, Melbourne, Victoria, Australia ; Monash Obesity & Diabetes Institute, Monash University, Clayton, Victoria, Australia
| | - D E Cummings
- Division of Metabolism, Endocrinology and Nutrition, Department of Medicine, University of Washington School of Medicine, Seattle, WA, USA
| | - A Dagher
- McConnell Brain Imaging Centre, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
| | - S Diano
- Dept of Neurobiology, Yale University School of Medicine, New Haven, CT, USA
| | - S L Dickson
- Department of Physiology/Endocrinology, Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
| | - C Diéguez
- Department of Physiology, School of Medicine, Instituto de Investigacion Sanitaria (IDIS), University of Santiago de Compostela, Spain
| | - R Granata
- Division of Endocrinology, Diabetes and Metabolism, Dept. of Medical Sciences, University of Torino, Torino, Italy
| | - H J Grill
- Department of Psychology, Institute of Diabetes, Obesity and Metabolism, University of Pennsylvania, Philadelphia, PA, USA
| | - K Grove
- Department of Diabetes, Obesity and Metabolism, Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, OR, USA
| | - K M Habegger
- Comprehensive Diabetes Center, University of Alabama School of Medicine, Birmingham, AL, USA
| | - K Heppner
- Division of Diabetes, Obesity, and Metabolism, Oregon National Primate Research Center, Oregon Health and Science University, Beaverton, OR 97006, USA
| | - M L Heiman
- NuMe Health, 1441 Canal Street, New Orleans, LA 70112, USA
| | - L Holsen
- Departments of Psychiatry and Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
| | - B Holst
- Department of Neuroscience and Pharmacology, University of Copenhagen, Copenhagen N, Denmark
| | - A Inui
- Department of Psychosomatic Internal Medicine, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - J O Jansson
- Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
| | - H Kirchner
- Medizinische Klinik I, Universitätsklinikum Schleswig-Holstein Campus Lübeck, Lübeck, Germany
| | - M Korbonits
- Centre for Endocrinology, William Harvey Research Institute, Barts and the London, Queen Mary University of London, London, UK
| | - B Laferrère
- New York Obesity Research Center, Department of Medicine, Columbia University College of Physicians and Surgeons, New York, NY, USA
| | - C W LeRoux
- Diabetes Complications Research Centre, Conway Institute, University College Dublin, Ireland
| | - M Lopez
- Department of Physiology, Centro de Investigación en Medicina Molecular y Enfermedades Crónicas, University of Santiago de Compostela (CIMUS)-Instituto de Investigación Sanitaria (IDIS)-CIBER Fisiopatología de la Obesidad y Nutrición (CIBERobn), Santiago de Compostela, Spain
| | - S Morin
- Institute for Diabetes and Obesity, Helmholtz Zentrum München, München, Germany
| | - M Nakazato
- Division of Neurology, Respirology, Endocrinology and Metabolism, Department of Internal Medicine, Faculty of Medicine, University of Miyazaki, Kiyotake, Miyazaki, Japan
| | - R Nass
- Division of Endocrinology and Metabolism, University of Virginia, Charlottesville, VA, USA
| | - D Perez-Tilve
- Department of Internal Medicine, Department of Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - P T Pfluger
- Institute for Diabetes and Obesity, Helmholtz Zentrum München, München, Germany
| | - T W Schwartz
- Department of Neuroscience and Pharmacology, Laboratory for Molecular Pharmacology, The Panum Institute, University of Copenhagen, Copenhagen, Denmark
| | - R J Seeley
- Department of Surgery, University of Michigan School of Medicine, Ann Arbor, MI, USA
| | - M Sleeman
- Department of Physiology, Faculty of Medicine, Monash University, Melbourne, Victoria, Australia
| | - Y Sun
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX, USA
| | - L Sussel
- Department of Genetics and Development, Columbia University, New York, NY, USA
| | - J Tong
- Duke Molecular Physiology Institute, Duke University, Durham, NC, USA
| | - M O Thorner
- Division of Endocrinology and Metabolism, University of Virginia, Charlottesville, VA, USA
| | - A J van der Lely
- Department of Medicine, Erasmus University MC, Rotterdam, The Netherlands
| | | | - J M Zigman
- Departments of Internal Medicine and Psychiatry, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - M Kojima
- Molecular Genetics, Institute of Life Science, Kurume University, Kurume, Japan
| | - K Kangawa
- National Cerebral and Cardiovascular Center Research Institute, Osaka, Japan
| | - R G Smith
- The Scripps Research Institute, Florida Department of Metabolism & Aging, Jupiter, FL, USA
| | - T Horvath
- Program in Integrative Cell Signaling and Neurobiology of Metabolism, Section of Comparative Medicine, Yale University School of Medicine, New Haven, CT, USA
| | - M H Tschöp
- Institute for Diabetes and Obesity, Helmholtz Zentrum München, München, Germany ; Division of Metabolic Diseases, Department of Medicine, Technical University Munich, Munich, Germany
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49
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Wellman MK, Patterson ZR, MacKay H, Darling JE, Mani BK, Zigman JM, Hougland JL, Abizaid A. Novel Regulator of Acylated Ghrelin, CF801, Reduces Weight Gain, Rebound Feeding after a Fast, and Adiposity in Mice. Front Endocrinol (Lausanne) 2015; 6:144. [PMID: 26441834 PMCID: PMC4585333 DOI: 10.3389/fendo.2015.00144] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Accepted: 09/01/2015] [Indexed: 01/04/2023] Open
Abstract
Ghrelin is a 28 amino acid hormonal peptide that is intimately related to the regulation of food intake and body weight. Once secreted, ghrelin binds to the growth hormone secretagogue receptor-1a, the only known receptor for ghrelin and is capable of activating a number of signaling cascades, ultimately resulting in an increase in food intake and adiposity. Because ghrelin has been linked to overeating and the development of obesity, a number of pharmacological interventions have been generated in order to interfere with either the activation of ghrelin or interrupting ghrelin signaling as a means to reducing appetite and decrease weight gain. Here, we present a novel peptide, CF801, capable of reducing circulating acylated ghrelin levels and subsequent body weight gain and adiposity. To this end, we show that IP administration of CF801 is sufficient to reduce circulating plasma acylated ghrelin levels. Acutely, intraperitoneal injections of CF801 resulted in decreased rebound feeding after an overnight fast. When delivered chronically, they decreased weight gain and adiposity without affecting caloric intake. CF801, however, did cause a change in diet preference, decreasing preference for a high-fat diet and increasing preference for regular chow diet. Given the complexity of ghrelin receptor function, we propose that CF801, along with other compounds that regulate ghrelin secretion, may prove to be a beneficial tool in the study of the ghrelin system, and potential targets for ghrelin-based obesity treatments without altering the function of ghrelin receptors.
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Affiliation(s)
| | | | - Harry MacKay
- Department of Neuroscience, Carleton University, Ottawa, ON, Canada
| | | | - Bharath K. Mani
- Department of Internal Medicine, Division of Hypothalamic Research, The University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Internal Medicine, Division of Endocrinology and Metabolism, The University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Psychiatry, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Jeffrey M. Zigman
- Department of Internal Medicine, Division of Hypothalamic Research, The University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Internal Medicine, Division of Endocrinology and Metabolism, The University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Psychiatry, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | | | - Alfonso Abizaid
- Department of Neuroscience, Carleton University, Ottawa, ON, Canada
- *Correspondence: Alfonso Abizaid, Department of Neuroscience, Carleton University, 1125 Colonel By Drive, 329 Life Science Research Building, Ottawa, ON K1S 5B6, Canada,
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50
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Uchida A, Zechner JF, Mani BK, Park WM, Aguirre V, Zigman JM. Altered ghrelin secretion in mice in response to diet-induced obesity and Roux-en-Y gastric bypass. Mol Metab 2014; 3:717-30. [PMID: 25353000 PMCID: PMC4209356 DOI: 10.1016/j.molmet.2014.07.009] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Revised: 07/22/2014] [Accepted: 07/25/2014] [Indexed: 01/06/2023] Open
Abstract
The current study examined potential mechanisms for altered circulating ghrelin levels observed in diet-induced obesity (DIO) and following weight loss resulting from Roux-en-Y gastric bypass (RYGB). We hypothesized that circulating ghrelin levels were altered in obesity and after weight loss through changes in ghrelin cell responsiveness to physiological cues. We confirmed lower ghrelin levels in DIO mice and demonstrated elevated ghrelin levels in mice 6 weeks post-RYGB. In both DIO and RYGB settings, these changes in ghrelin levels were associated with altered ghrelin cell responsiveness to two key physiological modulators of ghrelin secretion - glucose and norepinephrine. In DIO mice, increases in ghrelin cell density within both the stomach and duodenum and in somatostatin-immunoreactive D cell density in the duodenum were observed. Our findings provide new insights into the regulation of ghrelin secretion and its relation to circulating ghrelin within the contexts of obesity and weight loss.
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Affiliation(s)
- Aki Uchida
- Division of Hypothalamic Research, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX, USA ; Division of Endocrinology & Metabolism, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX, USA ; Department of Psychiatry, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Juliet F Zechner
- Division of Hypothalamic Research, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX, USA ; Division of Digestive and Liver Diseases, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Bharath K Mani
- Division of Hypothalamic Research, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX, USA ; Division of Endocrinology & Metabolism, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX, USA ; Department of Psychiatry, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Won-Mee Park
- Division of Hypothalamic Research, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX, USA ; Division of Endocrinology & Metabolism, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX, USA ; Department of Psychiatry, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Vincent Aguirre
- Division of Hypothalamic Research, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX, USA ; Division of Digestive and Liver Diseases, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Jeffrey M Zigman
- Division of Hypothalamic Research, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX, USA ; Division of Endocrinology & Metabolism, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX, USA ; Department of Psychiatry, The University of Texas Southwestern Medical Center, Dallas, TX, USA
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