1
|
Li H, Xu Y, Jiang Y, Jiang Z, Otiz-Guzman J, Morrill JC, Cai J, Mao Z, Xu Y, Arenkiel BR, Huang C, Tong Q. The melanocortin action is biased toward protection from weight loss in mice. Nat Commun 2023; 14:2200. [PMID: 37069175 PMCID: PMC10110624 DOI: 10.1038/s41467-023-37912-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2022] [Accepted: 04/05/2023] [Indexed: 04/19/2023] Open
Abstract
The melanocortin action is well perceived for its ability to regulate body weight bidirectionally with its gain of function reducing body weight and loss of function promoting obesity. However, this notion cannot explain the difficulty in identifying effective therapeutics toward treating general obesity via activation of the melanocortin action. Here, we provide evidence that altered melanocortin action is only able to cause one-directional obesity development. We demonstrate that chronic inhibition of arcuate neurons expressing proopiomelanocortin (POMC) or paraventricular hypothalamic neurons expressing melanocortin receptor 4 (MC4R) causes massive obesity. However, chronic activation of these neuronal populations failed to reduce body weight. Furthermore, gain of function of the melanocortin action through overexpression of MC4R, POMC or its derived peptides had little effect on obesity prevention or reversal. These results reveal a bias of the melanocortin action towards protection of weight loss and provide a neural basis behind the well-known, but mechanistically ill-defined, predisposition to obesity development.
Collapse
Affiliation(s)
- Hongli Li
- School of Pharmacy, Shanghai University of Traditional Chinese Medicine, 1200 Cailun Road, Shanghai, 201203, China
- Brown Foundation of Molecular Medicine for the Prevention of Human Diseases of McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX, 77030, USA
| | - Yuanzhong Xu
- Brown Foundation of Molecular Medicine for the Prevention of Human Diseases of McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX, 77030, USA
| | - Yanyan Jiang
- Brown Foundation of Molecular Medicine for the Prevention of Human Diseases of McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX, 77030, USA
| | - Zhiying Jiang
- Brown Foundation of Molecular Medicine for the Prevention of Human Diseases of McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX, 77030, USA
| | - Joshua Otiz-Guzman
- Department of Molecular and Human Genetics and Department of Neuroscience, Baylor College of Medicine, and Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | - Jessie C Morrill
- Brown Foundation of Molecular Medicine for the Prevention of Human Diseases of McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX, 77030, USA
- MD Anderson Cancer Center & UTHealth Graduate School for Biomedical Sciences, University of Texas Health Science at Houston, 77030, Houston, TX, USA
| | - Jing Cai
- Brown Foundation of Molecular Medicine for the Prevention of Human Diseases of McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX, 77030, USA
- MD Anderson Cancer Center & UTHealth Graduate School for Biomedical Sciences, University of Texas Health Science at Houston, 77030, Houston, TX, USA
| | - Zhengmei Mao
- Brown Foundation of Molecular Medicine for the Prevention of Human Diseases of McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX, 77030, USA
| | - Yong Xu
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA
| | - Benjamin R Arenkiel
- Department of Molecular and Human Genetics and Department of Neuroscience, Baylor College of Medicine, and Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX, USA
| | - Cheng Huang
- School of Pharmacy, Shanghai University of Traditional Chinese Medicine, 1200 Cailun Road, Shanghai, 201203, China.
| | - Qingchun Tong
- Brown Foundation of Molecular Medicine for the Prevention of Human Diseases of McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX, 77030, USA.
- MD Anderson Cancer Center & UTHealth Graduate School for Biomedical Sciences, University of Texas Health Science at Houston, 77030, Houston, TX, USA.
- Department of Neurobiology and Anatomy of McGovern Medical School, University of Texas Health Science Center at Houston, Houston, TX, 77030, USA.
| |
Collapse
|
2
|
Neurohormonal Changes in the Gut–Brain Axis and Underlying Neuroendocrine Mechanisms following Bariatric Surgery. Int J Mol Sci 2022; 23:ijms23063339. [PMID: 35328759 PMCID: PMC8954280 DOI: 10.3390/ijms23063339] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 03/15/2022] [Accepted: 03/16/2022] [Indexed: 02/05/2023] Open
Abstract
Obesity is a complex, multifactorial disease that is a major public health issue worldwide. Currently approved anti-obesity medications and lifestyle interventions lack the efficacy and durability needed to combat obesity, especially in individuals with more severe forms or coexisting metabolic disorders, such as poorly controlled type 2 diabetes. Bariatric surgery is considered an effective therapeutic modality with sustained weight loss and metabolic benefits. Numerous genetic and environmental factors have been associated with the pathogenesis of obesity, while cumulative evidence has highlighted the gut–brain axis as a complex bidirectional communication axis that plays a crucial role in energy homeostasis. This has led to increased research on the roles of neuroendocrine signaling pathways and various gastrointestinal peptides as key mediators of the beneficial effects following weight-loss surgery. The accumulate evidence suggests that the development of gut-peptide-based agents can mimic the effects of bariatric surgery and thus is a highly promising treatment strategy that could be explored in future research. This article aims to elucidate the potential underlying neuroendocrine mechanisms of the gut–brain axis and comprehensively review the observed changes of gut hormones associated with bariatric surgery. Moreover, the emerging role of post-bariatric gut microbiota modulation is briefly discussed.
Collapse
|
3
|
Saucisse N, Mazier W, Simon V, Binder E, Catania C, Bellocchio L, Romanov RA, Léon S, Matias I, Zizzari P, Quarta C, Cannich A, Meece K, Gonzales D, Clark S, Becker JM, Yeo GSH, Fioramonti X, Merkle FT, Wardlaw SL, Harkany T, Massa F, Marsicano G, Cota D. Functional heterogeneity of POMC neurons relies on mTORC1 signaling. Cell Rep 2021; 37:109800. [PMID: 34644574 DOI: 10.1016/j.celrep.2021.109800] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 07/21/2021] [Accepted: 09/15/2021] [Indexed: 12/14/2022] Open
Abstract
Hypothalamic pro-opiomelanocortin (POMC) neurons are known to trigger satiety. However, these neuronal cells encompass heterogeneous subpopulations that release γ-aminobutyric acid (GABA), glutamate, or both neurotransmitters, whose functions are poorly defined. Using conditional mutagenesis and chemogenetics, we show that blockade of the energy sensor mechanistic target of rapamycin complex 1 (mTORC1) in POMC neurons causes hyperphagia by mimicking a cellular negative energy state. This is associated with decreased POMC-derived anorexigenic α-melanocyte-stimulating hormone and recruitment of POMC/GABAergic neurotransmission, which is restrained by cannabinoid type 1 receptor signaling. Electrophysiology and optogenetic studies further reveal that pharmacological blockade of mTORC1 simultaneously activates POMC/GABAergic neurons and inhibits POMC/glutamatergic ones, implying that the functional specificity of these subpopulations relies on mTORC1 activity. Finally, POMC neurons with different neurotransmitter profiles possess specific molecular signatures and spatial distribution. Altogether, these findings suggest that mTORC1 orchestrates the activity of distinct POMC neurons subpopulations to regulate feeding behavior.
Collapse
Affiliation(s)
- Nicolas Saucisse
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, F-3300 Bordeaux, France
| | - Wilfrid Mazier
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, F-3300 Bordeaux, France
| | - Vincent Simon
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, F-3300 Bordeaux, France
| | - Elke Binder
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, F-3300 Bordeaux, France
| | - Caterina Catania
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, F-3300 Bordeaux, France
| | - Luigi Bellocchio
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, F-3300 Bordeaux, France
| | - Roman A Romanov
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, A-1090 Vienna, Austria
| | - Stéphane Léon
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, F-3300 Bordeaux, France
| | - Isabelle Matias
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, F-3300 Bordeaux, France
| | - Philippe Zizzari
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, F-3300 Bordeaux, France
| | - Carmelo Quarta
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, F-3300 Bordeaux, France
| | - Astrid Cannich
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, F-3300 Bordeaux, France
| | - Kana Meece
- Department of Medicine, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA
| | - Delphine Gonzales
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, F-3300 Bordeaux, France
| | - Samantha Clark
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, F-3300 Bordeaux, France
| | - Julia M Becker
- 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
| | - Xavier Fioramonti
- NutriNeuro, UMR 1286 INRAE, Bordeaux University, Bordeaux INP, F-33000 Bordeaux, France
| | - Florian T Merkle
- 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; Wellcome Trust-MRC Cambridge Stem Cell Institute, Cambridge Biomedical Campus, Puddicombe Way, Cambridge CB2 0AW, UK
| | - Sharon L Wardlaw
- Department of Medicine, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA
| | - Tibor Harkany
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, A-1090 Vienna, Austria; Department of Neuroscience, Karolinska Institutet, SE-17177 Stockholm, Sweden
| | - Federico Massa
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, F-3300 Bordeaux, France
| | - Giovanni Marsicano
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, F-3300 Bordeaux, France
| | - Daniela Cota
- University of Bordeaux, INSERM, Neurocentre Magendie, U1215, F-3300 Bordeaux, France.
| |
Collapse
|
4
|
Bruschetta G, Jin S, Liu ZW, Kim JD, Diano S. MC 4R Signaling in Dorsal Raphe Nucleus Controls Feeding, Anxiety, and Depression. Cell Rep 2021; 33:108267. [PMID: 33053350 DOI: 10.1016/j.celrep.2020.108267] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 07/28/2020] [Accepted: 09/22/2020] [Indexed: 12/21/2022] Open
Abstract
Major depressive disorder is associated with weight loss and decreased appetite; however, the signaling that connects these conditions is unclear. Here, we show that MC4R signaling in the dorsal raphe nucleus (DRN) affects feeding, anxiety, and depression. DRN infusion of α-MSH decreases DRN neuronal activation and feeding. DRN MC4R is expressed in GABAergic PRCP-producing neurons. DRN selective knockdown of PRCP (PrcpDRNKD), an enzyme inactivating α-MSH, decreases feeding and DRN neuronal activation. Interestingly, PrcpDRNKD mice present lower DRN serotonin levels and depressive-like behavior. Similarly, PRCP-ablated MC4R mice (PrcpMC4RKO) show metabolic and behavioral phenotypes comparable to those of PrcpDRNKD mice. Selective PRCP re-expression in DRN MC4R neurons of PrcpMC4RKO mice partially reverses feeding, while fully restoring mood behaviors. Chemogenetic inhibition of DRN MC4R neurons induces anxiety, depression, and reduced feeding, whereas chemogenetic activation reverses these effects. Our results indicate that MC4R signaling in DRN plays a role in feeding, anxiety, and depression.
Collapse
Affiliation(s)
- Giuseppe Bruschetta
- Department of Cellular & Molecular Physiology, Yale University School of Medicine, New Haven, CT 06520, USA; Program of Integrative Cell Signaling and Neurobiology of Metabolism, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Sungho Jin
- Department of Cellular & Molecular Physiology, Yale University School of Medicine, New Haven, CT 06520, USA; Program of Integrative Cell Signaling and Neurobiology of Metabolism, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Zhong-Wu Liu
- Program of Integrative Cell Signaling and Neurobiology of Metabolism, Yale University School of Medicine, New Haven, CT 06520, USA; Department of Comparative Medicine, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Jung Dae Kim
- Department of Cellular & Molecular Physiology, Yale University School of Medicine, New Haven, CT 06520, USA; Program of Integrative Cell Signaling and Neurobiology of Metabolism, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Sabrina Diano
- Department of Cellular & Molecular Physiology, Yale University School of Medicine, New Haven, CT 06520, USA; Program of Integrative Cell Signaling and Neurobiology of Metabolism, Yale University School of Medicine, New Haven, CT 06520, USA; Department of Comparative Medicine, Yale University School of Medicine, New Haven, CT 06520, USA; Department of Neuroscience, Yale University School of Medicine, New Haven, CT 06520, USA.
| |
Collapse
|
5
|
Fortin SM, Chen J, Hayes MR. Hindbrain melanocortin 3/4 receptors modulate the food intake and body weight suppressive effects of the GLP-1 receptor agonist, liraglutide. Physiol Behav 2020; 220:112870. [PMID: 32179053 PMCID: PMC7227776 DOI: 10.1016/j.physbeh.2020.112870] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Revised: 01/14/2020] [Accepted: 03/09/2020] [Indexed: 12/19/2022]
Abstract
Simultaneously targeting multiple energy balance control systems is a promising direction for the development of obesity pharmacotherapies. Here, we explore the interaction between the GLP-1 and melanocortin system within the dorsal vagal complex (DVC) of the caudal brainstem. Using a pharmacological approach, we demonstrate that the full anorectic potential of liraglutide, an FDA-approved GLP-1 analog for the treatment of obesity, requires DVC melanocortin 3/4 receptor (MC3/4R) signaling. Specifically, the food intake and body weight suppressive effects of liraglutide were attenuated by DVC administration of the MC3/4R antagonist SHU9119. In contrast, the anorectic effects of liraglutide were enhanced by combined activation of DVC MC3/4Rs using the agonist MTII. Our findings highlight the modulation of liraglutide-induced anorexia by DVC MC3/4R signaling, thereby suggesting a site of action at which two important energy balance control systems interact.
Collapse
Affiliation(s)
- Samantha M Fortin
- Department of Psychiatry, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States.
| | - Jack Chen
- Department of Psychiatry, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States
| | - Matthew R Hayes
- Department of Psychiatry, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, United States.
| |
Collapse
|
6
|
Sarvestani FS, Zare MA, Saki F, Koohpeyma F, Al-Abdullah IH, Azarpira N. The effect of human wharton's jelly-derived mesenchymal stem cells on MC4R, NPY, and LEPR gene expression levels in rats with streptozotocin-induced diabetes. IRANIAN JOURNAL OF BASIC MEDICAL SCIENCES 2020; 23:214-223. [PMID: 32405365 PMCID: PMC7211357 DOI: 10.22038/ijbms.2019.39582.9387] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/13/2019] [Accepted: 08/03/2019] [Indexed: 12/17/2022]
Abstract
OBJECTIVES Type 1 diabetes (T1D) is an autoimmune disease resulting from inflammatory destruction of islets β-cells. Nowadays, progress in cell therapy, especially mesenchymal stem cells (MSCs) proposes numerous potential remedies for T1D. We aimed to investigate the combination therapeutic effect of these cells with insulin and metformin on neuropeptide Y, melanocortin-4 receptor, and leptin receptor genes expression in TID. MATERIALS AND METHODS One hundreds male rats were randomly divided into seven groups: the control, diabetes, insulin (Ins.), insulin+metformin (Ins.Met.), Wharton's Jelly-derived MSCs (WJ-MSCs), insulin+metformin+WJ-MSCs (Ins.Met.MSCs), and insulin+WJ-MSCs (Ins.MSCs). Treatment was performed from the first day after diagnosis as diabetes. Groups of the recipient WJ-MSCs were intraportally injected with 2× 10⁶ MSCs/kg at the 7th and 28th days of study. Fasting blood sugar was monitored and tissues and genes analysis were performed. RESULTS The blood glucose levels were slightly decreased in all treatment groups within 20th and 45th days compared to the diabetic group. The C-peptide level enhanced in these groups compared to the diabetic group, but this increment in Ins.MSCs group on the 45th days was higher than other groups. The expression level of melanocortin-4 receptor and leptin receptor genes meaningfully up-regulated in the treatment groups, while the expression of neuropeptide Y significantly down-regulated in the treatment group on both times of study. CONCLUSION Our data exhibit that infusion of MSCs and its combination therapy with insulin might ameliorate diabetes signs by changing the amount of leptin and subsequent changes in the expression of neuropeptide Y and melanocortin-4 receptor.
Collapse
Affiliation(s)
| | - Mohammad Ali Zare
- Transplant Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Forough Saki
- Endocrinology and Metabolism Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Farhad Koohpeyma
- Endocrinology and Metabolism Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Ismail H Al-Abdullah
- Department of Translational Research and Cellular Therapeutics, Diabetes and Metabolism Research Institute, Beckman Research Institute of City of Hope, Duarte, USA
| | - Negar Azarpira
- Transplant Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| |
Collapse
|
7
|
Thompson DL, Valencia NA, Walker NL, Oberhaus EL. Melanocyte-Stimulating Hormone Response to Exercise, Twitching, Epinephrine Injection, Substance P Injection, and Prostaglandin-F 2α Administration in Mares. J Equine Vet Sci 2019; 77:114-120. [PMID: 31133303 DOI: 10.1016/j.jevs.2019.03.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Revised: 03/12/2019] [Accepted: 03/12/2019] [Indexed: 12/01/2022]
Abstract
Five experiments were performed to test the hypothesis that α-melanocyte-stimulating hormone (MSH) is secreted in response to various stressors in horses similar to prolactin, growth hormone, and adrenocorticotropin (ACTH). There was considerable variation in resting concentrations of MSH and in the degree of stimulation in responders; thus all data sets were tested for heterogeneity of variance and corrected for as needed before analysis. In experiment 1, 12 mares were used in a switchback design to test the effect of a 2-minute exercise bout on MSH secretion. Plasma MSH concentrations were constant when mares were not exercised but increased (P < .05) immediately (2 minutes) after exercise and were still elevated 5 minutes later. In experiment 2, six mares were twitched for 2 minutes and six mares were not twitched. Twitching stimulated (P < .05) both MSH and ACTH relative to controls. Experiments 3, 4, and 5 tested the acute effects of intravenous injection of epinephrine at 5 μg/kg of body weight, intravenous injection of 100 μg substance P, and intramuscular injection of 10 mg prostaglandin-F2α in mares compared to controls (6, 5, and 6 mares per treatment group, respectively). Concentrations of MSH increased (P ≤ .05) after treatment in all three experiments. Plasma concentrations of ACTH also increased (P < .01) after administration of epinephrine and prostaglandin-F2α in experiments 3 and 5; plasma ACTH was not measured in experiment 1 or 4 because we have previously reported that exercise and substance P stimulate plasma ACTH concentrations. As hypothesized, MSH is secreted in response to various stimuli similar to that observed previously for prolactin, growth hormone, and ACTH.
Collapse
Affiliation(s)
- Donald L Thompson
- School of Animal Sciences, Louisiana Agricultural Experiment Station, LSU AgCenter, Baton Rouge, LA.
| | - Nicole Arana Valencia
- School of Animal Sciences, Louisiana Agricultural Experiment Station, LSU AgCenter, Baton Rouge, LA
| | - Neely L Walker
- School of Animal Sciences, Louisiana Agricultural Experiment Station, LSU AgCenter, Baton Rouge, LA
| | - Erin L Oberhaus
- School of Animal Sciences, Louisiana Agricultural Experiment Station, LSU AgCenter, Baton Rouge, LA
| |
Collapse
|
8
|
Panigrahi SK, Meece K, Wardlaw SL. Effects of Naltrexone on Energy Balance and Hypothalamic Melanocortin Peptides in Male Mice Fed a High-Fat Diet. J Endocr Soc 2019; 3:590-601. [PMID: 30820484 PMCID: PMC6388658 DOI: 10.1210/js.2018-00379] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Accepted: 01/23/2019] [Indexed: 01/16/2023] Open
Abstract
The hypothalamic melanocortin system composed of proopiomelanocortin (POMC) and agouti-related protein (AgRP) neurons plays a key role in maintaining energy homeostasis. The POMC-derived peptides, α-MSH and β-EP, have distinct roles in this process. α-MSH inhibits food intake, whereas β-EP, an endogenous opioid, can inhibit POMC neurons and stimulate food intake. A mouse model was used to examine the effects of opioid antagonism with naltrexone (NTX) on Pomc and Agrp gene expression and POMC peptide processing in the hypothalamus in conjunction with changes in energy balance. There were clear stimulatory effects of NTX on hypothalamic Pomc in mice receiving low- and high-fat diets, yet only transient decreases in food intake and body weight gain were noted. The effects on Pomc expression were accompanied by an increase in POMC prohormone levels and a decrease in levels of the processed peptides α-MSH and β-EP. Arcuate expression of the POMC processing enzymes Pcsk1, Pcsk2, and Cpe was not altered by NTX, but expression of Prcp, an enzyme that inactivates α-MSH, increased after NTX exposure. NTX exposure also stimulated hypothalamic Agrp expression, but the effects of NTX on energy balance were not enhanced in Agrp-null mice. Despite clear stimulatory effects of NTX on Pomc expression in the hypothalamus, only modest transient decreases in food intake and body weight were seen. Effects of NTX on POMC processing, and possibly α-MSH inactivation, as well as stimulatory effects on AgRP neurons could mitigate the effects of NTX on energy balance.
Collapse
Affiliation(s)
- Sunil K Panigrahi
- Department of Medicine, Division of Endocrinology, Vagelos College of Physicians and Surgeons, Columbia University, New York, New York
| | - Kana Meece
- Department of Medicine, Division of Endocrinology, Vagelos College of Physicians and Surgeons, Columbia University, New York, New York
| | - Sharon L Wardlaw
- Department of Medicine, Division of Endocrinology, Vagelos College of Physicians and Surgeons, Columbia University, New York, New York
| |
Collapse
|
9
|
Kirwan P, Kay RG, Brouwers B, Herranz-Pérez V, Jura M, Larraufie P, Jerber J, Pembroke J, Bartels T, White A, Gribble FM, Reimann F, Farooqi IS, O'Rahilly S, Merkle FT. Quantitative mass spectrometry for human melanocortin peptides in vitro and in vivo suggests prominent roles for β-MSH and desacetyl α-MSH in energy homeostasis. Mol Metab 2018; 17:82-97. [PMID: 30201275 PMCID: PMC6197775 DOI: 10.1016/j.molmet.2018.08.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Revised: 08/08/2018] [Accepted: 08/16/2018] [Indexed: 12/23/2022] Open
Abstract
OBJECTIVE The lack of pro-opiomelanocortin (POMC)-derived melanocortin peptides results in hypoadrenalism and severe obesity in both humans and rodents that is treatable with synthetic melanocortins. However, there are significant differences in POMC processing between humans and rodents, and little is known about the relative physiological importance of POMC products in the human brain. The aim of this study was to determine which POMC-derived peptides are present in the human brain, to establish their relative concentrations, and to test if their production is dynamically regulated. METHODS We analysed both fresh post-mortem human hypothalamic tissue and hypothalamic neurons derived from human pluripotent stem cells (hPSCs) using liquid chromatography tandem mass spectrometry (LC-MS/MS) to determine the sequence and quantify the production of hypothalamic neuropeptides, including those derived from POMC. RESULTS In both in vitro and in vivo hypothalamic cells, LC-MS/MS revealed the sequence of hundreds of neuropeptides as a resource for the field. Although the existence of β-melanocyte stimulating hormone (MSH) is controversial, we found that both this peptide and desacetyl α-MSH (d-α-MSH) were produced in considerable excess of acetylated α-MSH. In hPSC-derived hypothalamic neurons, these POMC derivatives were appropriately trafficked, secreted, and their production was significantly (P < 0.0001) increased in response to the hormone leptin. CONCLUSIONS Our findings challenge the assumed pre-eminence of α-MSH and suggest that in humans, d-α-MSH and β-MSH are likely to be the predominant physiological products acting on melanocortin receptors.
Collapse
Affiliation(s)
- Peter Kirwan
- Metabolic Research Laboratories and Medical Research Council Metabolic Diseases Unit, Wellcome Trust-Medical Research Council Institute of Metabolic Science, University of Cambridge, Cambridge, CB2 0QQ, UK; The Anne McLaren Laboratory for Regenerative Medicine, Wellcome Trust-Medical Research Council Cambridge Stem Cell Institute, University of Cambridge, Cambridge, CB2 0SZ, UK
| | - Richard G Kay
- Metabolic Research Laboratories and Medical Research Council Metabolic Diseases Unit, Wellcome Trust-Medical Research Council Institute of Metabolic Science, University of Cambridge, Cambridge, CB2 0QQ, UK
| | - Bas Brouwers
- Metabolic Research Laboratories and Medical Research Council Metabolic Diseases Unit, Wellcome Trust-Medical Research Council Institute of Metabolic Science, University of Cambridge, Cambridge, CB2 0QQ, UK; The Anne McLaren Laboratory for Regenerative Medicine, Wellcome Trust-Medical Research Council Cambridge Stem Cell Institute, University of Cambridge, Cambridge, CB2 0SZ, UK
| | - Vicente Herranz-Pérez
- Laboratory of Comparative Neurobiology, Cavanilles Institute of Biodiversity and Evolutionary Biology, University of Valencia, CIBERNED, 46980 Valencia, Spain; Predepartamental Unit of Medicine, Faculty of Health Sciences, Universitat Jaume I, 12071 Castelló de la Plana, Spain
| | - Magdalena Jura
- Metabolic Research Laboratories and Medical Research Council Metabolic Diseases Unit, Wellcome Trust-Medical Research Council Institute of Metabolic Science, University of Cambridge, Cambridge, CB2 0QQ, UK; The Anne McLaren Laboratory for Regenerative Medicine, Wellcome Trust-Medical Research Council Cambridge Stem Cell Institute, University of Cambridge, Cambridge, CB2 0SZ, UK
| | - Pierre Larraufie
- Metabolic Research Laboratories and Medical Research Council Metabolic Diseases Unit, Wellcome Trust-Medical Research Council Institute of Metabolic Science, University of Cambridge, Cambridge, CB2 0QQ, UK
| | - Julie Jerber
- The Anne McLaren Laboratory for Regenerative Medicine, Wellcome Trust-Medical Research Council Cambridge Stem Cell Institute, University of Cambridge, Cambridge, CB2 0SZ, UK; Open Targets, Wellcome Trust Sanger Institute, Hinxton, CB10 1SA, UK
| | - Jason Pembroke
- LGC Ltd., Newmarket Road, Fordham, Cambridgeshire, CB7 5WW, UK
| | - Theresa Bartels
- The Anne McLaren Laboratory for Regenerative Medicine, Wellcome Trust-Medical Research Council Cambridge Stem Cell Institute, University of Cambridge, Cambridge, CB2 0SZ, UK
| | - Anne White
- Division of Diabetes, Endocrinology and Gastroenterology, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Fiona M Gribble
- Metabolic Research Laboratories and Medical Research Council Metabolic Diseases Unit, Wellcome Trust-Medical Research Council Institute of Metabolic Science, University of Cambridge, Cambridge, CB2 0QQ, UK
| | - Frank Reimann
- Metabolic Research Laboratories and Medical Research Council Metabolic Diseases Unit, Wellcome Trust-Medical Research Council Institute of Metabolic Science, University of Cambridge, Cambridge, CB2 0QQ, UK
| | - I Sadaf Farooqi
- Metabolic Research Laboratories and Medical Research Council Metabolic Diseases Unit, Wellcome Trust-Medical Research Council Institute of Metabolic Science, University of Cambridge, Cambridge, CB2 0QQ, UK
| | - Stephen O'Rahilly
- Metabolic Research Laboratories and Medical Research Council Metabolic Diseases Unit, Wellcome Trust-Medical Research Council Institute of Metabolic Science, University of Cambridge, Cambridge, CB2 0QQ, UK
| | - Florian T Merkle
- Metabolic Research Laboratories and Medical Research Council Metabolic Diseases Unit, Wellcome Trust-Medical Research Council Institute of Metabolic Science, University of Cambridge, Cambridge, CB2 0QQ, UK; The Anne McLaren Laboratory for Regenerative Medicine, Wellcome Trust-Medical Research Council Cambridge Stem Cell Institute, University of Cambridge, Cambridge, CB2 0SZ, UK.
| |
Collapse
|
10
|
Pozo M, Claret M. Hypothalamic Control of Systemic Glucose Homeostasis: The Pancreas Connection. Trends Endocrinol Metab 2018; 29:581-594. [PMID: 29866501 DOI: 10.1016/j.tem.2018.05.001] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Revised: 05/10/2018] [Accepted: 05/12/2018] [Indexed: 12/22/2022]
Abstract
Maintenance of glucose homeostasis is mandatory for organismal survival. It is accomplished by complex and coordinated interplay between glucose detection mechanisms and multiple effector systems. The brain, in particular homeostatic regions such as the hypothalamus, plays a crucial role in orchestrating such a highly integral response. We review here current understanding of how the hypothalamus senses glucose availability and participates in systemic glucose homeostasis. We provide an update of the relevant signaling pathways and neuronal subsets involved, as well as of the mechanisms modulating metabolic processes in peripheral tissues such as liver, skeletal muscle, fat, and especially the pancreas. We also discuss the relevance of these networks in human biology and prevalent metabolic conditions such as diabetes and obesity.
Collapse
Affiliation(s)
- Macarena Pozo
- Neuronal Control of Metabolism (NeuCoMe) Laboratory, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), 08036 Barcelona, Spain
| | - Marc Claret
- Neuronal Control of Metabolism (NeuCoMe) Laboratory, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), 08036 Barcelona, Spain; Centro de Investigación Biomédica en Red (CIBER) de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), 08036 Barcelona, Spain.
| |
Collapse
|
11
|
Nuutinen S, Ailanen L, Savontaus E, Rinne P. Melanocortin overexpression limits diet-induced inflammation and atherosclerosis in LDLR -/- mice. J Endocrinol 2018; 236:111-123. [PMID: 29317531 DOI: 10.1530/joe-17-0636] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Accepted: 01/09/2018] [Indexed: 12/26/2022]
Abstract
Atherosclerosis is a chronic inflammatory disease of the arteries. The disease is initiated by endothelial dysfunction that allows the transport of leukocytes and low-density lipoprotein into the vessel wall forming atherosclerotic plaques. The melanocortin system is an endogenous peptide system that regulates, for example, energy homeostasis and cardiovascular function. Melanocortin treatment with endogenous or synthetic melanocortin peptides reduces body weight, protects the endothelium and alleviates vascular inflammation, but the long-term effects of melanocortin system activation on atheroprogression remain largely unknown. In this study, we evaluated the effects of transgenic melanocortin overexpression in a mouse model of atherosclerosis. Low-density lipoprotein receptor-deficient mice overexpressing alpha- and gamma3-MSH (MSH-OE) and their wild-type littermates were fed either a regular chow or Western-style diet for 16 weeks. During this time, their metabolic parameters were monitored. The aortae were collected for functional analysis, and the plaques in the aortic root and arch were characterised by histological and immunohistochemical stainings. The aortic expression of inflammatory mediators was determined by quantitative PCR. We found that transgenic MSH-OE improved glucose tolerance and limited atherosclerotic plaque formation particularly in Western diet-fed mice. In terms of aortic vasoreactivity, MSH-OE blunted alpha1-adrenoceptor-mediated vasoconstriction and enhanced relaxation response to acetylcholine, indicating improved endothelial function. In addition, MSH-OE markedly attenuated Western diet-induced upregulation of proinflammatory cytokines (Ccl2, Ccl5 and Il6) that contribute to the pathogenesis of atherosclerosis. These results show that the activation of the melanocortin system improves glucose homeostasis and limits diet-induced vascular inflammation and atherosclerotic plaque formation.
Collapse
Affiliation(s)
- Salla Nuutinen
- Research Center for Integrative Physiology and Pharmacologyand Turku Center for Disease Modeling, Institute of Biomedicine, University of Turku, Turku, Finland
| | - Liisa Ailanen
- Research Center for Integrative Physiology and Pharmacologyand Turku Center for Disease Modeling, Institute of Biomedicine, University of Turku, Turku, Finland
| | - Eriika Savontaus
- Research Center for Integrative Physiology and Pharmacologyand Turku Center for Disease Modeling, Institute of Biomedicine, University of Turku, Turku, Finland
- Unit of Clinical PharmacologyTurku University Hospital, Turku, Finland
| | - Petteri Rinne
- Research Center for Integrative Physiology and Pharmacologyand Turku Center for Disease Modeling, Institute of Biomedicine, University of Turku, Turku, Finland
| |
Collapse
|
12
|
Prolyl carboxypeptidase in Agouti-related Peptide neurons modulates food intake and body weight. Mol Metab 2018; 10:28-38. [PMID: 29459251 PMCID: PMC5985234 DOI: 10.1016/j.molmet.2018.02.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Revised: 01/26/2018] [Accepted: 02/04/2018] [Indexed: 12/15/2022] Open
Abstract
Objective Prolyl carboxypeptidase (PRCP) plays a role in the regulation of energy metabolism by inactivating hypothalamic α-melanocyte stimulating hormone (α-MSH) levels. Although detected in the arcuate nucleus, limited PRCP expression has been observed in the arcuate POMC neurons, and its site of action in regulating metabolism is still ill-defined. Methods We performed immunostaining to assess the localization of PRCP in arcuate Neuropeptide Y/Agouti-related Peptide (NPY/AgRP) neurons. Hypothalamic explants were then used to assess the intracellular localization of PRCP and its release at the synaptic levels. Finally, we generated a mouse model to assess the role of PRCP in NPY/AgRP neurons of the arcuate nucleus in the regulation of metabolism. Results Here we show that PRCP is expressed in NPY/AgRP-expressing neurons of the arcuate nucleus. In hypothalamic explants, stimulation by ghrelin increased PRCP concentration in the medium and decreased PRCP content in synaptic extract, suggesting that PRCP is released at the synaptic level. In support of this, hypothalamic explants from mice with selective deletion of PRCP in AgRP neurons (PrcpAgRPKO) showed reduced ghrelin-induced PRCP concentration in the medium compared to controls mice. Furthermore, male PrcpAgRPKO mice had decreased body weight and fat mass compared to controls. However, this phenotype was sex-specific as female PrcpAgRPKO mice show metabolic differences only when challenged by high fat diet feeding. The improved metabolism of PrcpAgRPKO mice was associated with reduced food intake and increased energy expenditure, locomotor activity, and hypothalamic α-MSH levels. Administration of SHU9119, a potent melanocortin receptor antagonist, selectively in the PVN of PrcpAgRPKO male mice increased food intake to a level similar to that of control mice. Conclusions Altogether, our data indicate that PRCP is released at the synaptic levels and that PRCP in AgRP neurons contributes to the modulation of α-MSH degradation and related metabolic control in mice. PRCP is expressed in the arcuate NPY/AgRP neurons. PRCP is released in the synaptic space following ghrelin stimulation. Male mice with PRCP deletion in NPY/AgRP neurons show leaner phenotype with decreased food intake on standard chow diet. Female mice with PRCP deletion in NPY/AgRP neurons show leaner phenotype with decreased food intake only on high fat diet. Selective blockade of PVN melanocortin receptors increases feeding in male mice with PRCP deletion in NPY/AgRP neurons.
Collapse
|
13
|
Do Neuroendocrine Peptides and Their Receptors Qualify as Novel Therapeutic Targets in Osteoarthritis? Int J Mol Sci 2018; 19:ijms19020367. [PMID: 29373492 PMCID: PMC5855589 DOI: 10.3390/ijms19020367] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Revised: 01/22/2018] [Accepted: 01/23/2018] [Indexed: 01/15/2023] Open
Abstract
Joint tissues like synovium, articular cartilage, meniscus and subchondral bone, are targets for neuropeptides. Resident cells of these tissues express receptors for various neuroendocrine-derived peptides including proopiomelanocortin (POMC)-derived peptides, i.e., α-melanocyte-stimulating hormone (α-MSH), adrenocorticotropin (ACTH) and β-endorphin (β-ED), and sympathetic neuropeptides like vasoactive intestinal peptide (VIP) and neuropeptide y (NPY). Melanocortins attained particular attention due to their immunomodulatory and anti-inflammatory effects in several tissues and organs. In particular, α-MSH, ACTH and specific melanocortin-receptor (MCR) agonists appear to have promising anti-inflammatory actions demonstrated in animal models of experimentally induced arthritis and osteoarthritis (OA). Sympathetic neuropeptides have obtained increasing attention as they have crucial trophic effects that are critical for joint tissue and bone homeostasis. VIP and NPY are implicated in direct and indirect activation of several anabolic signaling pathways in bone and synovial cells. Additionally, pituitary adenylate cyclase-activating polypeptide (PACAP) proved to be chondroprotective and, thus, might be a novel target in OA. Taken together, it appears more and more likely that the anabolic effects of these neuroendocrine peptides or their respective receptor agonists/antagonists may be exploited for the treatment of patients with inflammatory and degenerative joint diseases in the future.
Collapse
|
14
|
Lam DD, de Souza FSJ, Nasif S, Yamashita M, López-Leal R, Otero-Corchon V, Meece K, Sampath H, Mercer AJ, Wardlaw SL, Rubinstein M, Low MJ. Partially redundant enhancers cooperatively maintain Mammalian pomc expression above a critical functional threshold. PLoS Genet 2015; 11:e1004935. [PMID: 25671638 PMCID: PMC4335486 DOI: 10.1371/journal.pgen.1004935] [Citation(s) in RCA: 83] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Accepted: 12/02/2014] [Indexed: 11/29/2022] Open
Abstract
Cell-specific expression of many genes is conveyed by multiple enhancers, with each individual enhancer controlling a particular expression domain. In contrast, multiple enhancers drive similar expression patterns of some genes involved in embryonic development, suggesting regulatory redundancy. Work in Drosophila has indicated that functionally overlapping enhancers canalize development by buffering gene expression against environmental and genetic disturbances. However, little is known about regulatory redundancy in vertebrates and in genes mainly expressed during adulthood. Here we study nPE1 and nPE2, two phylogenetically conserved mammalian enhancers that drive expression of the proopiomelanocortin gene (Pomc) to the same set of hypothalamic neurons. The simultaneous deletion of both enhancers abolished Pomc expression at all ages and induced a profound metabolic dysfunction including early-onset extreme obesity. Targeted inactivation of either nPE1 or nPE2 led to very low levels of Pomc expression during early embryonic development indicating that both enhancers function synergistically. In adult mice, however, Pomc expression is controlled additively by both enhancers, with nPE1 being responsible for ∼80% and nPE2 for ∼20% of Pomc transcription. Consequently, nPE1 knockout mice exhibit mild obesity whereas nPE2-deficient mice maintain a normal body weight. These results suggest that nPE2-driven Pomc expression is compensated by nPE1 at later stages of development, essentially rescuing the earlier phenotype of nPE2 deficiency. Together, these results reveal that cooperative interactions between the enhancers confer robustness of Pomc expression against gene regulatory disturbances and preclude deleterious metabolic phenotypes caused by Pomc deficiency in adulthood. Thus, our study demonstrates that enhancer redundancy can be used by genes that control adult physiology in mammals and underlines the potential significance of regulatory sequence mutations in common diseases. The stability of animal form and function in the face of genetic and environmental variation relies on consistent gene expression. Multiple enhancers, each specifying a unique regulatory domain, control the precise spatiotemporal expression of many genes. However, in some genes apparently redundant enhancers regulate expression in overlapping cell-specific patterns. Although this arrangement has been shown to be important for developmental robustness in invertebrates, the role of apparently redundant enhancers in vertebrate species and in genes functioning in adulthood is poorly understood. Here, we show that expression of the mammalian Pomc gene is controlled in a tissue-specific manner by two such apparently redundant enhancers. We used targeted deletion of the individual enhancers to delineate their respective contributions to Pomc expression in the brain. Since Pomc expression from its intact locus exceeds the sum of the individual enhancer contributions to Pomc mRNA levels in embryonic mice, we infer a synergistic action between the enhancers during development. In contrast, the interaction between the enhancers is additive in adult mice. Deletion of both enhancers simultaneously almost completely abolished Pomc expression and the mutant mice displayed extreme obesity and metabolic dysfunction, while deletion of the individual enhancers had a modest or no phenotypic effect. Together, our results demonstrate that the two enhancers cooperatively maintain Pomc expression above a critical functional threshold.
Collapse
Affiliation(s)
- Daniel D. Lam
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Flavio S. J. de Souza
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina
- Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Sofia Nasif
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina
| | - Miho Yamashita
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | | | - Veronica Otero-Corchon
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Kana Meece
- Department of Medicine, Columbia University College of Physicians and Surgeons, New York, New York, United States of America
| | - Harini Sampath
- Center for Research on Occupational and Environmental Toxicology, Oregon Health & Science University, Portland, Oregon, United States of America
| | - Aaron J. Mercer
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Sharon L. Wardlaw
- Department of Medicine, Columbia University College of Physicians and Surgeons, New York, New York, United States of America
| | - Marcelo Rubinstein
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
- Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina
- Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Malcolm J. Low
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
- * E-mail:
| |
Collapse
|
15
|
Jeong JK, Kim JG, Lee BJ. Participation of the central melanocortin system in metabolic regulation and energy homeostasis. Cell Mol Life Sci 2014; 71:3799-809. [PMID: 24894870 PMCID: PMC11113577 DOI: 10.1007/s00018-014-1650-z] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Revised: 04/23/2014] [Accepted: 05/12/2014] [Indexed: 10/25/2022]
Abstract
Obesity and metabolic disorders, such as type 2 diabetes and hypertension, have attracted considerable attention as life-threatening diseases not only in developed countries but also worldwide. Additionally, the rate of obesity in young people all over the world is rapidly increasing. Accumulated evidence suggests that the central nervous system may participate in the development of and/or protection from obesity. For example, in the brain, the hypothalamic melanocortin system senses and integrates central and peripheral metabolic signals and controls the degree of energy expenditure and feeding behavior, in concert with metabolic status, to regulate whole-body energy homeostasis. Currently, researchers are studying the mechanisms by which peripheral metabolic molecules control feeding behavior and energy balance through the central melanocortin system. Accordingly, recent studies have revealed that some inflammatory molecules and transcription factors participate in feeding behavior and energy balance by controlling the central melanocortin pathway, and have thus become new candidates as therapeutic targets to fight metabolic diseases such as obesity and diabetes.
Collapse
Affiliation(s)
- Jin Kwon Jeong
- Department of Biology and Biochemistry, Center for Nuclear Receptors and Cell Signaling, University of Houston, Houston, TX 77004 USA
| | - Jae Geun Kim
- Program in Integrative Cell Signaling and Neurobiology of Metabolism, Section of Comparative Medicine, Yale University School of Medicine, New Haven, CT 06520 USA
| | - Byung Ju Lee
- Department of Biological Sciences, University of Ulsan, Ulsan, 680-749 South Korea
| |
Collapse
|
16
|
Eerola K, Rinne P, Penttinen AM, Vähätalo L, Savontaus M, Savontaus E. α-MSH overexpression in the nucleus tractus solitarius decreases fat mass and elevates heart rate. J Endocrinol 2014; 222:123-36. [PMID: 24829220 DOI: 10.1530/joe-14-0064] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The POMC pathway is involved in the regulation of energy and cardiovascular homeostasis in the hypothalamus and the brain stem. Although the acute effects of POMC-derived peptides in different brain locations have been elucidated, the chronic site-specific effects of distinct peptides remain to be studied. To this end, we used a lentiviral gene delivery vector to study the long-term effects of α-MSH in the nucleus tractus solitarius (NTS) of the brain stem. The α-MSH vector (LVi-α-MSH-EGFP) based on the N-terminal POMC sequence and a control vector (LVi-EGFP) were delivered into the NTS of C57BL/6N male mice fed on a western diet. Effects on body weight and composition, feeding, glucose metabolism, and hemodynamics by telemetric analyses were studied during the 12-week follow-up. The LVi-α-MSH-EGFP-treated mice had a significantly smaller gain in the fat mass compared with LVi-EGFP-injected mice. There was a small initial decrease in food intake and no differences in the physical activity. Glucose metabolism was not changed compared with the control. LVi-α-MSH-EGFP increased the heart rate (HR), which was attenuated by adrenergic blockade suggesting an increased sympathetic activity. Reduced response to muscarinic blockade suggested a decreased parasympathetic activity. Fitting with sympathetic activation, LVi-α-MSH-EGFP treatment reduced urine secretion. Thus, the results demonstrate that long-term α-MSH overexpression in the NTS attenuates diet-induced obesity. Modulation of autonomic nervous system tone increased the HR and most probably contributed to an anti-obesity effect. The results underline the key role of NTS in the α-MSH-induced long-term effects on adiposity and in regulation of sympathetic and parasympathetic activities.
Collapse
Affiliation(s)
- K Eerola
- Department of PharmacologyDrug Development and Therapeutics and Turku Center for Disease Modeling, University of Turku, Kiinamyllynkatu 10, 20520 Turku, FinlandTurku Centre for BiotechnologyUniversity of Turku, Turku, FinlandDrug Research Doctoral ProgramUniversity of Turku, Turku, FinlandHeart CenterTurku University Hospital and University of Turku, Turku, FinlandUnit of Clinical PharmacologyTurku University Hospital, Turku, FinlandDepartment of PharmacologyDrug Development and Therapeutics and Turku Center for Disease Modeling, University of Turku, Kiinamyllynkatu 10, 20520 Turku, FinlandTurku Centre for BiotechnologyUniversity of Turku, Turku, FinlandDrug Research Doctoral ProgramUniversity of Turku, Turku, FinlandHeart CenterTurku University Hospital and University of Turku, Turku, FinlandUnit of Clinical PharmacologyTurku University Hospital, Turku, FinlandDepartment of PharmacologyDrug Development and Therapeutics and Turku Center for Disease Modeling, University of Turku, Kiinamyllynkatu 10, 20520 Turku, FinlandTurku Centre for BiotechnologyUniversity of Turku, Turku, FinlandDrug Research Doctoral ProgramUniversity of Turku, Turku, FinlandHeart CenterTurku University Hospital and University of Turku, Turku, FinlandUnit of Clinical PharmacologyTurku University Hospital, Turku, Finland
| | - P Rinne
- Department of PharmacologyDrug Development and Therapeutics and Turku Center for Disease Modeling, University of Turku, Kiinamyllynkatu 10, 20520 Turku, FinlandTurku Centre for BiotechnologyUniversity of Turku, Turku, FinlandDrug Research Doctoral ProgramUniversity of Turku, Turku, FinlandHeart CenterTurku University Hospital and University of Turku, Turku, FinlandUnit of Clinical PharmacologyTurku University Hospital, Turku, Finland
| | - A M Penttinen
- Department of PharmacologyDrug Development and Therapeutics and Turku Center for Disease Modeling, University of Turku, Kiinamyllynkatu 10, 20520 Turku, FinlandTurku Centre for BiotechnologyUniversity of Turku, Turku, FinlandDrug Research Doctoral ProgramUniversity of Turku, Turku, FinlandHeart CenterTurku University Hospital and University of Turku, Turku, FinlandUnit of Clinical PharmacologyTurku University Hospital, Turku, Finland
| | - L Vähätalo
- Department of PharmacologyDrug Development and Therapeutics and Turku Center for Disease Modeling, University of Turku, Kiinamyllynkatu 10, 20520 Turku, FinlandTurku Centre for BiotechnologyUniversity of Turku, Turku, FinlandDrug Research Doctoral ProgramUniversity of Turku, Turku, FinlandHeart CenterTurku University Hospital and University of Turku, Turku, FinlandUnit of Clinical PharmacologyTurku University Hospital, Turku, FinlandDepartment of PharmacologyDrug Development and Therapeutics and Turku Center for Disease Modeling, University of Turku, Kiinamyllynkatu 10, 20520 Turku, FinlandTurku Centre for BiotechnologyUniversity of Turku, Turku, FinlandDrug Research Doctoral ProgramUniversity of Turku, Turku, FinlandHeart CenterTurku University Hospital and University of Turku, Turku, FinlandUnit of Clinical PharmacologyTurku University Hospital, Turku, Finland
| | - M Savontaus
- Department of PharmacologyDrug Development and Therapeutics and Turku Center for Disease Modeling, University of Turku, Kiinamyllynkatu 10, 20520 Turku, FinlandTurku Centre for BiotechnologyUniversity of Turku, Turku, FinlandDrug Research Doctoral ProgramUniversity of Turku, Turku, FinlandHeart CenterTurku University Hospital and University of Turku, Turku, FinlandUnit of Clinical PharmacologyTurku University Hospital, Turku, FinlandDepartment of PharmacologyDrug Development and Therapeutics and Turku Center for Disease Modeling, University of Turku, Kiinamyllynkatu 10, 20520 Turku, FinlandTurku Centre for BiotechnologyUniversity of Turku, Turku, FinlandDrug Research Doctoral ProgramUniversity of Turku, Turku, FinlandHeart CenterTurku University Hospital and University of Turku, Turku, FinlandUnit of Clinical PharmacologyTurku University Hospital, Turku, Finland
| | - E Savontaus
- Department of PharmacologyDrug Development and Therapeutics and Turku Center for Disease Modeling, University of Turku, Kiinamyllynkatu 10, 20520 Turku, FinlandTurku Centre for BiotechnologyUniversity of Turku, Turku, FinlandDrug Research Doctoral ProgramUniversity of Turku, Turku, FinlandHeart CenterTurku University Hospital and University of Turku, Turku, FinlandUnit of Clinical PharmacologyTurku University Hospital, Turku, FinlandDepartment of PharmacologyDrug Development and Therapeutics and Turku Center for Disease Modeling, University of Turku, Kiinamyllynkatu 10, 20520 Turku, FinlandTurku Centre for BiotechnologyUniversity of Turku, Turku, FinlandDrug Research Doctoral ProgramUniversity of Turku, Turku, FinlandHeart CenterTurku University Hospital and University of Turku, Turku, FinlandUnit of Clinical PharmacologyTurku University Hospital, Turku, Finland
| |
Collapse
|
17
|
Schneeberger M, Gomis R, Claret M. Hypothalamic and brainstem neuronal circuits controlling homeostatic energy balance. J Endocrinol 2014; 220:T25-46. [PMID: 24222039 DOI: 10.1530/joe-13-0398] [Citation(s) in RCA: 184] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Alterations in adequate energy balance maintenance result in serious metabolic disturbances such as obesity. In mammals, this complex process is orchestrated by multiple and distributed neuronal circuits. Hypothalamic and brainstem neuronal circuits are critically involved in the sensing of circulating and local factors conveying information about the energy status of the organism. The integration of these signals culminates in the generation of specific and coordinated physiological responses aimed at regulating energy balance through the modulation of appetite and energy expenditure. In this article, we review current knowledge on the homeostatic regulation of energy balance, emphasizing recent advances in mouse genetics, electrophysiology, and optogenetic techniques that have greatly contributed to improving our understanding of this central process.
Collapse
Affiliation(s)
- Marc Schneeberger
- Diabetes and Obesity Research Laboratory, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), 08036 Barcelona, Spain Department of Endocrinology and Nutrition, School of Medicine, Hospital Clínic, University of Barcelona, 08036 Barcelona, Spain Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), 08036 Barcelona, Spain
| | | | | |
Collapse
|
18
|
Eerola K, Nordlund W, Virtanen S, Dickens AM, Mattila M, Ruohonen ST, Chua SC, Wardlaw SL, Savontaus M, Savontaus E. Lentivirus-mediated α-melanocyte-stimulating hormone overexpression in the hypothalamus decreases diet induced obesity in mice. J Neuroendocrinol 2013; 25:1298-1307. [PMID: 24118213 DOI: 10.1111/jne.12109] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2013] [Revised: 09/20/2013] [Accepted: 09/21/2013] [Indexed: 11/29/2022]
Abstract
Melanocyte stimulating hormone (MSH) derived from the pro-hormone pro-opiomelanocortin (POMC) has potent effects on metabolism and feeding that lead to reduced body weight in the long-term. To determine the individual roles of POMC derived peptides and their sites of action, we created a method for the delivery of single MSH peptides using lentiviral vectors and studied the long-term anti-obesity effects of hypothalamic α-MSH overexpression in mice. An α-MSH lentivirus (LVi-α-MSH-EGFP) vector carrying the N'-terminal part of POMC and the α-MSH sequence was generated and shown to produce bioactive peptide in an in vitro melanin synthesis assay. Stereotaxis was used to deliver the LVi-α-MSH-EGFP or control LVi-EGFP vector to the arcuate nucleus (ARC) of the hypothalamus of male C57Bl/6N mice fed on a high-fat diet. The effects of 6-week-treatment on body weight, food intake, glucose tolerance and organ weights were determined. Additionally, a 14-day pairfeeding study was conducted to assess whether the weight decreasing effect of the LVi-α-MSH-EGFP treatment is dependent on decreased food intake. The 6-week LVi-α-MSH-EGFP treatment reduced weight gain (8.4 ± 0.4 g versus 12.3 ± 0.6 g; P < 0.05), which was statistically significant starting from 1 week after the injections. The weight of mesenteric fat was decreased and glucose tolerance was improved compared to LVi-EGFP treated mice. Food intake was decreased during the first week in the LVi-α-MSH-EGFP treated mice but subsequently increased to the level of LVi-EGFP treated mice. The LVi-EGFP injected control mice gained more weight even when pairfed to the level of food intake by LVi-α-MSH-EGFP treated mice. We demonstrate that gene transfer of α-MSH, a single peptide product of POMC, into the ARC of the hypothalamus, reduces obesity and improves glucose tolerance, and that factors other than decreased food intake also influence the weight decreasing effects of α-MSH overexpression in the ARC. Furthermore, viral MSH vectors delivered stereotaxically provide a novel tool for further exploration of chronic site-specific effects of POMC peptides.
Collapse
Affiliation(s)
- K Eerola
- Department of Pharmacology, Drug Development and Therapeutics, and Turku Center for Disease Modeling, University of Turku, Turku, Finland
- Turku Centre for Biotechnology, University of Turku, Turku, Finland
- FinPharma Doctoral Program, Drug Discovery Section, Turku, Finland
| | - W Nordlund
- Department of Pharmacology, Drug Development and Therapeutics, and Turku Center for Disease Modeling, University of Turku, Turku, Finland
| | - S Virtanen
- Department of Pharmacology, Drug Development and Therapeutics, and Turku Center for Disease Modeling, University of Turku, Turku, Finland
- Turku Centre for Biotechnology, University of Turku, Turku, Finland
| | - A M Dickens
- Department of Pharmacology, Drug Development and Therapeutics, and Turku Center for Disease Modeling, University of Turku, Turku, Finland
- Turku PET Centre, Medicity/PET Preclinical Imaging, University of Turku, Turku, Finland
| | - M Mattila
- Turku Centre for Biotechnology, University of Turku, Turku, Finland
- Medical Biochemistry and Genetics, University of Turku, Turku, Finland
| | - S T Ruohonen
- Department of Pharmacology, Drug Development and Therapeutics, and Turku Center for Disease Modeling, University of Turku, Turku, Finland
| | - S C Chua
- Albert Einstein College of Medicine, New York, NY, USA
| | - S L Wardlaw
- Department of Medicine, Columbia University College of Physicians & Surgeons, New York, NY, USA
| | - M Savontaus
- Turku Centre for Biotechnology, University of Turku, Turku, Finland
- Turku Heart Center, Turku University Hospital and University of Turku, Turku, Finland
| | - E Savontaus
- Department of Pharmacology, Drug Development and Therapeutics, and Turku Center for Disease Modeling, University of Turku, Turku, Finland
- Unit of Clinical Pharmacology, Turku University Hospital, Turku, Finland
| |
Collapse
|
19
|
Rinne P, Harjunpää J, Mäkelä S, Savontaus E. Genetic and pharmacological mouse models of chronic melanocortin activation show enhanced baroreflex control of heart rate. ACTA ACUST UNITED AC 2013; 182:19-27. [DOI: 10.1016/j.regpep.2012.12.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2012] [Revised: 09/05/2012] [Accepted: 12/17/2012] [Indexed: 10/27/2022]
|
20
|
Rinne P, Nordlund W, Heinonen I, Penttinen AM, Saraste A, Ruohonen ST, Mäkelä S, Vähätalo L, Kaipio K, Cai M, Hruby VJ, Ruohonen S, Savontaus E. α-Melanocyte-stimulating hormone regulates vascular NO availability and protects against endothelial dysfunction. Cardiovasc Res 2012; 97:360-8. [PMID: 23131503 DOI: 10.1093/cvr/cvs335] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
AIMS α-Melanocyte-stimulating hormone (α-MSH), derived from the precursor molecule pro-opiomelanocortin, exerts potent anti-inflammatory actions in the vasculature, but its role in circulatory regulation remains unclear. Therefore, we sought to investigate whether α-MSH could regulate the local control of blood vessel tone. METHODS AND RESULTS Using in vivo and ex vivo methods to assess vascular reactivity, we found that α-MSH improved endothelium-dependent vasodilatation in the mouse aorta and coronary circulation without directly contracting or relaxing blood vessels. α-MSH promoted vasodilatation by enhancing endothelial nitric oxide (NO) formation and by improving sensitivity to endothelium-independent blood vessel relaxation. Using cultured human endothelial cells to elucidate the involved molecular mechanisms, we show that α-MSH increased the expression and phosphorylation of endothelial NO synthase in these cells. The observed effects were regulated by melanocortin 1 (MC1) receptors expressed in the endothelium. In keeping with the vascular protective role of α-MSH, in vivo treatment with stable analogues of α-MSH ameliorated endothelial dysfunction associated with aging and diet-induced obesity in mice. CONCLUSION The present study identifies α-MSH and endothelial MC1 receptors as a new signalling pathway contributing to the regulation of NO availability and vascular function. These findings suggest applicability of α-MSH analogues for therapeutic use in pathological conditions that are characterized by vascular dysfunction.
Collapse
Affiliation(s)
- Petteri Rinne
- Department of Pharmacology, Drug Development and Pharmaceutics, and Turku Center for Disease Modeling, Itäinen Pitkäkatu 4b, 20014 University of Turku, Turku, Finland.
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
21
|
Dutia R, Kim AJ, Mosharov E, Savontaus E, Chua SC, Wardlaw SL. Regulation of prolactin in mice with altered hypothalamic melanocortin activity. Peptides 2012; 37:6-12. [PMID: 22800691 PMCID: PMC3465950 DOI: 10.1016/j.peptides.2012.07.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2012] [Revised: 07/04/2012] [Accepted: 07/06/2012] [Indexed: 11/15/2022]
Abstract
This study used two mouse models with genetic manipulation of the melanocortin system to investigate prolactin regulation. Mice with overexpression of the melanocortin receptor (MC-R) agonist, α-melanocyte-stimulating hormone (Tg-MSH) or deletion of the MC-R antagonist agouti-related protein (AgRP KO) were studied. Male Tg-MSH mice had lower blood prolactin levels at baseline (2.9±0.3 vs. 4.7±0.7ng/ml) and after restraint stress (68±6.5 vs. 117±22ng/ml) vs. WT (p<0.05); however, pituitary prolactin content was not different. Blood prolactin was also decreased in male AgRP KO mice at baseline (4.2±0.5 vs. 7.6±1.3ng/ml) and after stress (60±4.5 vs. 86.1±5.7ng/ml) vs. WT (p<0.001). Pituitary prolactin content was lower in male AgRP KO mice (4.3±0.3 vs. 6.7±0.5μg/pituitary, p<0.001) vs. WT. No differences in blood or pituitary prolactin levels were observed in female AgRP KO mice vs. WT. Hypothalamic dopamine activity was assessed as the potential mechanism responsible for changes in prolactin levels. Hypothalamic tyrosine hydroxylase mRNA was measured in both genetic models vs. WT mice and hypothalamic dopamine and 3,4-dihydroxyphenylacetic acid (DOPAC) content were measured in male AgRP KO and WT mice but neither were significantly different. However, these results do not preclude changes in dopamine activity as dopamine turnover was not directly investigated. This is the first study to show that baseline and stress-induced prolactin release and pituitary prolactin content are reduced in mice with genetic alterations of the melanocortin system and suggests that changes in hypothalamic melanocortin activity may be reflected in measurements of serum prolactin levels.
Collapse
Affiliation(s)
- Roxanne Dutia
- Department of Medicine, Columbia University College of Physicians & Surgeons, New York, N.Y
| | - Andrea J. Kim
- Department of Medicine, Columbia University College of Physicians & Surgeons, New York, N.Y
| | - Eugene Mosharov
- Department of Neurology, Columbia University College of Physicians & Surgeons, New York, N.Y
| | - Eriika Savontaus
- Department of Pharmacology, Drug Development and Therapeutics, University of Turku, Turku, Finland
| | - Streamson C. Chua
- Department of Medicine, Albert Einstein College of Medicine, New York, NY
| | - Sharon L. Wardlaw
- Department of Medicine, Columbia University College of Physicians & Surgeons, New York, N.Y
| |
Collapse
|
22
|
Jeong JK, Szabo G, Raso GM, Meli R, Diano S. Deletion of prolyl carboxypeptidase attenuates the metabolic effects of diet-induced obesity. Am J Physiol Endocrinol Metab 2012; 302:E1502-10. [PMID: 22454290 PMCID: PMC3378159 DOI: 10.1152/ajpendo.00544.2011] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
α-Melanocyte-stimulating hormone (α-MSH) is a critical regulator of energy metabolism. Prolyl carboxypeptidase (PRCP) is an enzyme responsible for its degradation and inactivation. PRCP-null mice (PRCP(gt/gt)) showed elevated levels of brain α-MSH, reduced food intake, and a leaner phenotype compared with wild-type controls. In addition, they were protected against diet-induced obesity. Here, we show that PRCP(gt/gt) animals have improved metabolic parameters compared with wild-type controls under a standard chow diet (SD) as well as on a high-fat diet (HFD). Similarly to when they are exposed to SD, PRCP(gt/gt) mice exposed to HFD for 13 wk showed a leaner phenotype due to decreased fat mass, increased energy expenditure, and locomotor activity. They also showed improved insulin sensitivity and glucose tolerance compared with WT controls and a significant reduction in fasting glucose levels. These improvements occured before changes in body weight and composition were evident, suggesting that the beneficial effect of PRCP ablation is independent of the adiposity levels. In support of a reduced gluconeogenesis, liver PEPCK and G-6-Pase mRNA levels were reduced significantly in PRCP(gt/gt) compared with WT mice. A significant decrease in liver weight and hepatic triglycerides were also observed in PRCP(gt/gt) compared with WT mice. Altogether, our data suggest that PRCP is an important regulator of energy and glucose homeostasis since its deletion significantly improves metabolic parameters in mice exposed to both SD and HFD.
Collapse
Affiliation(s)
- Jin Kwon Jeong
- Program in Integrative Cell Signaling and Neurobiology of Metabolism, Yale University School of Medicine, New Haven, Connecticut 06520-208063, USA
| | | | | | | | | |
Collapse
|
23
|
Andino LM, Ryder DJ, Shapiro A, Matheny MK, Zhang Y, Judge MK, Cheng KY, Tümer N, Scarpace PJ. POMC overexpression in the ventral tegmental area ameliorates dietary obesity. J Endocrinol 2011; 210:199-207. [PMID: 21565854 DOI: 10.1530/joe-10-0418] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The activation of proopiomelanocortin (POMC) neurons in different regions of the brain, including the arcuate nucleus of the hypothalamus (ARC) and the nucleus of the solitary tract curtails feeding and attenuates body weight. In this study, we compared the effects of delivery of a recombinant adeno-associated viral (rAAV) construct encoding POMC to the ARC with delivery to the ventral tegmental area (VTA). F344×Brown Norway rats were high-fat (HF) fed for 14 days after which self-complementary rAAV constructs expressing either green fluorescent protein or the POMC gene were injected using coordinates targeting either the VTA or the ARC. Corresponding increased POMC levels were found at the predicted injection sites and subsequent α-melanocyte-stimulating hormone levels were observed. Food intake and body weight were measured for 4 months. Although caloric intake was unaltered by POMC overexpression, weight gain was tempered with POMC overexpression in either the VTA or the ARC compared with controls. There were parallel decreases in adipose tissue reserves. In addition, levels of oxygen consumption and brown adipose tissue uncoupling protein 1 were significantly elevated with POMC treatment in the VTA. Interestingly, tyrosine hydroxylase levels were increased in both the ARC and VTA with POMC overexpression in either the ARC or the VTA. In conclusion, these data indicate a role for POMC overexpression within the VTA reward center to combat HF-induced obesity.
Collapse
Affiliation(s)
- Lourdes M Andino
- Departments of Pharmacology and Therapeutics Aging and Geriatrics, University of Florida College of Medicine, PO Box 100267, Gainesville, Florida 32610, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
24
|
Leckstrom A, Lew PS, Poritsanos NJ, Mizuno TM. Treatment with a melanocortin agonist improves abnormal lipid metabolism in streptozotocin-induced diabetic mice. Neuropeptides 2011; 45:123-9. [PMID: 21216462 DOI: 10.1016/j.npep.2010.12.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2010] [Revised: 11/28/2010] [Accepted: 12/17/2010] [Indexed: 01/09/2023]
Abstract
Impairments in leptin-melanocortin signaling are associated with insulin-deficient diabetes and leptin treatment has been shown to be effective in reversing hyperglycemia in animal models of type 1 diabetes. Therefore, we hypothesized that enhanced central melanocortin signaling reverses the metabolic impairments associated with type 1 diabetes. To address this hypothesis, streptozotocin (STZ)-induced diabetic mice were treated with daily intracerebroventricular injection of MTII, a melanocortin agonist, for 11days. STZ-induced hyperglycemia and glucose intolerance were not improved by MTII treatment. MTII treatment did not alter expression levels of genes encoding gluconeogenic enzymes including glucose-6-phosphatase (G6Pase) and phosphoenolpyruvate carboxykinase (PEPCK), in the liver of diabetic mice. Skeletal muscle and white adipose tissue glucose transporter 4 (GLUT4) mRNA levels were not altered by MTII treatment in diabetic mice. In contrast, serum nonesterified fatty acid (NEFA) levels were significantly increased in STZ-induced diabetic mice compared to non-diabetic control mice and MTII treatment significantly reduced serum NEFA levels in diabetic mice. MTII treatment also significantly reduced expression levels of hormone sensitive lipase (HSL) and adipose triglyceride lipase (ATGL) mRNA in white adipose tissue of diabetic mice without a significant change in serum insulin levels. Expression levels of lipoprotein lipase (LPL) and fatty acid translocase (FAT/CD36) mRNA in white adipose tissue and skeletal muscle were not changed by MTII treatment. These data suggest that central melanocortin signaling regulates lipid metabolism and that enhancing central melanocortin signaling is effective in reversing abnormal lipid metabolism, but not carbohydrate metabolism, at least partly by reducing lipolysis in type 1 diabetes.
Collapse
Affiliation(s)
- Arnold Leckstrom
- Department of Physiology, University of Manitoba, 745 Bannatyne Avenue, Winnipeg, Manitoba, Canada R3E0J9
| | | | | | | |
Collapse
|
25
|
Zhang Y, Rodrigues E, Li G, Gao Y, King M, Carter CS, Tumer N, Cheng KY, Scarpace PJ. Simultaneous POMC gene transfer to hypothalamus and brainstem increases physical activity, lipolysis and reduces adult-onset obesity. Eur J Neurosci 2011; 33:1541-50. [PMID: 21366729 DOI: 10.1111/j.1460-9568.2011.07633.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Pro-opiomelanocortin (POMC) neurons are identified in two brain sites, the arcuate nucleus of the hypothalamus and nucleus of the solitary tract (NTS) in brainstem. Earlier pharmacological and POMC gene transfer studies demonstrate that melanocortin activation in either site alone improves insulin sensitivity and reduces obesity. The present study, for the first time, investigated the long-term efficacy of POMC gene transfer concurrently into both sites in the regulation of energy metabolism in aged F344xBN rats bearing adult-onset obesity. Pair feeding was included to reveal food-independent POMC impact on energy expenditure. We introduced adeno-associated virus encoding either POMC or green fluorescence protein to the two brain areas in 22-month-old rats, then recorded food intake and body weight, assessed oxygen consumption, serum leptin, insulin and glucose, tested voluntary wheel running, analysed POMC expression, and examined fat metabolism in brown and white adipose tissues. POMC mRNA was significantly increased in both the hypothalamus and NTS region at termination. Relative to pair feeding, POMC caused sustained weight reduction and additional fat loss, lowered fasting insulin and glucose, and augmented white fat hormone-sensitive lipase activity and brown fat uncoupling protein 1 level. By wheel running assessment, the POMC animals ran twice the distance as the Control or pair-fed rats. Thus, the dual-site POMC treatment ameliorated adult-onset obesity effectively, involving a moderate hypophagia lasting ∼60 days, enhanced lipolysis and thermogenesis, and increased physical activity in the form of voluntary wheel running. The latter finding provides a clue for countering age-related decline in physical activity.
Collapse
Affiliation(s)
- Yi Zhang
- Malcom Randall Veterans Affairs Medical Center, Gainesville, FL 32608, USA.
| | | | | | | | | | | | | | | | | |
Collapse
|
26
|
Wardlaw SL. Hypothalamic proopiomelanocortin processing and the regulation of energy balance. Eur J Pharmacol 2011; 660:213-9. [PMID: 21208604 DOI: 10.1016/j.ejphar.2010.10.107] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2010] [Revised: 09/27/2010] [Accepted: 10/12/2010] [Indexed: 12/18/2022]
Abstract
Hypothalamic proopiomelanocortin (POMC) neurons play a key role in regulating energy balance and neuroendocrine function. Much attention has been focused on the regulation of POMC gene expression with less emphasis on regulated peptide processing. This is particularly important given the complexity of posttranslational POMC processing which is essential for the generation of biologically active MSH peptides. Mutations that impair POMC sorting and processing are associated with obesity in humans and in animals. Specifically, mutations in the POMC processing enzymes prohormone convertase 1/3 (PC1/3) and in carboxypeptidase E (CPE) and in the α-MSH degrading enzyme, PRCP, are associated with changes in energy balance. There is increasing evidence that POMC processing is regulated with respect to energy balance. Studies have implicated both the leptin and insulin signaling pathways in the regulation of POMC at various steps in the processing pathway. This article will review the role of hypothalamic POMC in regulating energy balance with a focus on POMC processing.
Collapse
Affiliation(s)
- Sharon L Wardlaw
- Department of Medicine, Columbia University College of Physicians and Surgeons, New York, NY, United States.
| |
Collapse
|
27
|
New aspects of melanocortin signaling: a role for PRCP in α-MSH degradation. Front Neuroendocrinol 2011; 32:70-83. [PMID: 20932857 PMCID: PMC4766861 DOI: 10.1016/j.yfrne.2010.09.001] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2010] [Revised: 07/30/2010] [Accepted: 09/29/2010] [Indexed: 12/15/2022]
Abstract
The role of the central melanocortin system in the regulation of energy metabolism has received much attention during the past decade since gene mutations of key components in melanocortin signaling cause monogenic forms of obesity in animals and humans. In the arcuate nucleus of the hypothalamus the prohormone proopiomelanocortin (POMC) is posttranslationally cleaved to produce α-melanocyte stimulating hormone (α-MSH), a peptide with anorexigenic effects upon activation of the melanocortin receptors (MCRs). α-MSH undergoes extensive post-translational processing and its in vivo activity is short lived due to rapid degradation. The enzymatic process that controls α-MSH inactivation is incompletely understood. Recent evidence suggests that prolyl carboxypeptidase (PRCP) is an enzyme responsible for α-MSH degradation. As for many key melanocortin peptides, gene mutation of PRCP causes a change in the metabolic phenotype of rodents. This review summarizes the current knowledge on the melanocortin system with particular focus on PRCP, a newly discovered component of the melanocortin system.
Collapse
|
28
|
Soos S, Petervari E, Szekely M, Jech-Mihalffy A, Balasko M. Complex catabolic effects of central alpha-MSH infusion in rats of altered nutritional states: differences from leptin. J Mol Neurosci 2010; 43:209-16. [PMID: 20953734 DOI: 10.1007/s12031-010-9462-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2010] [Accepted: 10/05/2010] [Indexed: 01/15/2023]
Abstract
The hypothalamic melanocortin (MC) system is a major catabolic regulator of energy balance: it suppresses food intake (FI), elevates metabolic rate, and reduces body weight (BW). The primary activator of the MC system [mainly via the alpha-melanocyte stimulating hormone (alpha-MSH)] is the adipocyte-derived leptin. With increasing BW, resistance develops to leptin-induced anorexia, but independent of this, in genetically modified animals, some alpha-MSH actions were maintained. We investigated the responsiveness of the MC system in its complexity (FI vs. metabolic correlates) in genetically intact male Wistar rats of different nutritional states (and different leptin sensitivities), i.e., in rats aged 2 months [normally fed (NF2)] or 6 months [calorie-restricted (CR6), fed ad libitum (NF6), and high-fat diet-induced obese (HF6) groups]. A 7-day-long, 1-μg/μl/h intracerebroventricular infusion of alpha-MSH reduced BW in all groups, particularly in NF6 and NF2 animals, and even CR6 rats lost BW upon alpha-MSH infusion (in contrast to leptin administration). Anorexia developed in NF2-NF6 and less in CR6 groups, and some FI fall was also seen in HF6 rats. The hypermetabolic effects (temperature/heart rate elevations) were most pronounced in CR6 and next in HF6 rats. These data suggest that alpha-MSH responsiveness is maintained in various forms (depending on nutritional state), despite obesity-induced leptin resistance.
Collapse
Affiliation(s)
- Szilvia Soos
- Department of Pathophysiology and Gerontology, Medical School, University of Pecs, 12 Szigeti ut, Pecs H-7624, Hungary
| | | | | | | | | |
Collapse
|
29
|
Pro-opiomelanocortin gene transfer to the nucleus of the solitary track but not arcuate nucleus ameliorates chronic diet-induced obesity. Neuroscience 2010; 169:1662-71. [PMID: 20538045 DOI: 10.1016/j.neuroscience.2010.06.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2010] [Revised: 05/27/2010] [Accepted: 06/01/2010] [Indexed: 11/20/2022]
Abstract
Short-term pharmacological melanocortin activation deters diet-induced obesity (DIO) effectively in rodents. However, whether central pro-opiomelanocortin (POMC) gene transfer targeted to the hypothalamus or hindbrain nucleus of the solitary track (NTS) can combat chronic dietary obesity has not been investigated. Four-weeks-old Sprague-Dawley rats were fed a high fat diet for 5 months, and then injected with either the POMC or control vector into the hypothalamus or NTS, and body weight and food intake recorded for 68 days. Insulin sensitivity, glucose metabolism and adrenal indicators of central sympathetic activation were measured, and voluntary wheel running (WR) assessed. Whereas the NTS POMC-treatment decreased cumulative food consumption and caused a sustained weight reduction over 68 days, the hypothalamic POMC-treatment did not alter cumulative food intake and produced weight loss only in the first 25 days. At death, only the NTS-POMC rats had a significant decrease in fat mass. They also displayed enhanced glucose tolerance, lowered fasting insulin and increased QUICK value, and elevated adrenal indicators of central sympathetic activation. Moreover, the NTS-POMC animals exhibited a near 20% increase in distance ran relative to the respective controls, but the ARC-POMC rats did not. In conclusion, POMC gene transfer to the NTS caused modest anorexia, persistent weight loss, improved insulin sensitivity, and increased propensity for WR in DIO rats. These metabolic improvements may involve stimulation of energy expenditure via centrally regulated sympathetic outflow. The similar POMC treatment in the hypothalamus had minimal long-term physiological or metabolic impact. Thus, melanocortin activation in the brainstem NTS region effectively ameliorates chronic dietary obesity whilst that in the hypothalamus fails to do so.
Collapse
|
30
|
Mansour M, White D, Wernette C, Dennis J, Tao YX, Collins R, Parker L, Morrison E. Pancreatic neuronal melanocortin-4 receptor modulates serum insulin levels independent of leptin receptor. Endocrine 2010; 37:220-30. [PMID: 20963574 DOI: 10.1007/s12020-009-9289-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2009] [Accepted: 12/16/2009] [Indexed: 01/10/2023]
Abstract
The leptin-regulated melanocortin (MC) system modulates energy homeostasis and hypothalamic MC neuronal circuits regulate insulin secretion. We therefore hypothesized that MC system components were present in the pancreas. In order to determine the veracity of the hypothesis, we examined c-Fos, melanocortin-4 receptor (Mc4r), and alpha-melanocyte-stimulating hormone (α-MSH) expression levels in nondiabetic (intact leptin receptor signaling) and Zucker diabetic fatty (ZDF; leptin receptor deficiency) rats. We infused rats via the third ventricle with the α-MSH analog Nle4, D-Phe7-α-MSH (NDP-MSH), a Mc4r agonist. Subsequently, both hypothalamic and pancreatic c-Fos and Mc4r mRNAs were upregulated. Likewise, immunohistochemical analysis showed that an increased Mc4r and α-MSH expression in nerves surrounding the pancreatic vasculature and islets. Increases in c-Fos, α-MSH, and Mc4r expression were independent of leptin receptor function. Conversely, serum insulin was significantly reduced by NDP-MSH treatment, an effect which was reversed by the Mc4r specific blocker HS014. Finally, proopiomelanocortin (POMC) mRNA, the precursor of α-MSH, was detected by RT-PCR in pancreatic tissue homogenates. These findings suggest that pancreatic Mc4r and autonomic neurons participate in a communication pathway between the central MC system and pancreatic islets to regulate insulin secretion.
Collapse
Affiliation(s)
- Mahmoud Mansour
- Department of Anatomy, Physiology, and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL, USA.
| | | | | | | | | | | | | | | |
Collapse
|
31
|
Israel D, Chua S. Leptin receptor modulation of adiposity and fertility. Trends Endocrinol Metab 2010; 21:10-6. [PMID: 19854659 PMCID: PMC2818174 DOI: 10.1016/j.tem.2009.07.004] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2009] [Revised: 07/15/2009] [Accepted: 07/17/2009] [Indexed: 12/28/2022]
Abstract
The leptin receptor was discovered as a leptin binding protein, which is highly expressed in the choroid plexus. Mapping of the gene's chromosomal locations in rodents revealed that mutations in Lepr were the basis of obesity/diabetes mutations in rodents and humans. Genetic manipulations that target Lepr expression in specific neurons or hypothalamic areas have generated insights into the modes by which body composition and reproductive function are modulated by the leptin receptor. These animal models have also been instrumental in identifying diabetes susceptibility genes. In this review we discuss the evidence that supports the concept of networked functions of leptin receptor as it pertains to feeding, substrate utilization and reproduction.
Collapse
Affiliation(s)
| | - Streamson Chua
- Corresponding author Phone : 718-430-2986 Fax : 718-430-8557
| |
Collapse
|
32
|
Lew PS, Wong D, Yamaguchi T, Leckstrom A, Schwartz J, Dodd JG, Mizuno TM. Tail suspension increases energy expenditure independently of the melanocortin system in miceThis article is one of a selection of papers published in a special issue celebrating the 125th anniversary of the Faculty of Medicine at the University of Manitoba. Can J Physiol Pharmacol 2009; 87:839-49. [DOI: 10.1139/y09-074] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Space travelers experience anorexia and body weight loss in a microgravity environment, and microgravity-like situations cause changes in hypothalamic activity. Hypothalamic melanocortins play a critical role in the regulation of metabolism. Therefore, we hypothesized that microgravity affects metabolism through alterations in specific hypothalamic signaling pathways, including melanocortin signaling. To address this hypothesis, the microgravity-like situation was produced by an antiorthostatic tail suspension in wild-type and agouti mice, and the effect of tail suspension on energy expenditure and hypothalamic gene expression was examined. Energy expenditure was measured using indirect calorimetry before and during the tail suspension protocol. Hypothalamic tissues were collected for gene expression analysis at the end of the 3 h tail suspension period. Tail suspension significantly increased oxygen consumption, carbon dioxide production, and heat production in wild-type mice. Tail suspension-induced increases in energy expenditure were not attenuated in agouti mice. Although tail suspension did not alter hypothalamic proopiomelanocortin (POMC) and agouti-related protein (AGRP) mRNA levels, it significantly increased hypothalamic interleukin 6 (Il-6) mRNA levels. These data are consistent with the hypothesis that microgravity increases energy expenditure and suggest that these effects are mediated through hypothalamic signaling pathways that are independent of melanocortins, but possibly used by Il-6.
Collapse
Affiliation(s)
- Pei San Lew
- Department of Physiology, University of Manitoba, 745 Bannatyne Avenue, Winnipeg, MB R3E 0J9, Canada
| | - Davie Wong
- Department of Physiology, University of Manitoba, 745 Bannatyne Avenue, Winnipeg, MB R3E 0J9, Canada
| | - Takafumi Yamaguchi
- Department of Physiology, University of Manitoba, 745 Bannatyne Avenue, Winnipeg, MB R3E 0J9, Canada
| | - Arnold Leckstrom
- Department of Physiology, University of Manitoba, 745 Bannatyne Avenue, Winnipeg, MB R3E 0J9, Canada
| | - Jacquie Schwartz
- Department of Physiology, University of Manitoba, 745 Bannatyne Avenue, Winnipeg, MB R3E 0J9, Canada
| | - Janice G. Dodd
- Department of Physiology, University of Manitoba, 745 Bannatyne Avenue, Winnipeg, MB R3E 0J9, Canada
| | - Tooru M. Mizuno
- Department of Physiology, University of Manitoba, 745 Bannatyne Avenue, Winnipeg, MB R3E 0J9, Canada
| |
Collapse
|
33
|
Abstract
The hypothalamus has historically been subdivided into nuclei, agglomerations of cell bodies that are visually distinct in histological sections. Regulatory functions of metabolism have been assigned to the various hypothalamic nuclei principally by analysis of animals with lesions of individual nuclei but also via various means of stimulation, such as cooling or heating probes. Biochemical and molecular specificity of these studies became possible with the identification and synthesis of neurotransmitters as well as the means to manipulate the expression of endogenous neurotransmitters and their receptors by genetic means . The arcuate nucleus (ARC) is likely to be the primary site for neurons that sense circulating fuels and energy reserves (POMC/CART neurons, NPY/AGRP neurons), whereas the paraventricular nucleus (PVN) receives input from the ARC and harbors many of the releasing factors (CRF, TRH, vasopressin, and oxytocin) that control pituitary hormone release. The ventromedial nucleus (VMN) receives input from the ARC and plays a critical role in energy balance in parallel with the ARC. The VMN and PVN also send descending projections to the autonomic nervous system and other pathways that control ingestive behavior and metabolism. Developmental analyses have revealed that the neurons that comprise the hypothalamic nuclei arise by differentiation and migration from stem cells within the ventricular zone. Based on recent work, it is becoming clear that coordination between numerous transcription factors that determine specification, survival, and migration is necessary for the formation of the hypothalamus, with each nucleus being determined by its own unique set of factors. In this minireview, we will provide a selective view of the roles that transcription factors play in the developing hypothalamus.
Collapse
Affiliation(s)
- Young-Hwan Jo
- Departments of Medicine and Neuroscience, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | | |
Collapse
|
34
|
Wallingford N, Perroud B, Gao Q, Coppola A, Gyengesi E, Liu ZW, Gao XB, Diament A, Haus KA, Shariat-Madar Z, Mahdi F, Wardlaw SL, Schmaier AH, Warden CH, Diano S. Prolylcarboxypeptidase regulates food intake by inactivating alpha-MSH in rodents. J Clin Invest 2009; 119:2291-303. [PMID: 19620781 DOI: 10.1172/jci37209] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2008] [Accepted: 05/20/2009] [Indexed: 11/17/2022] Open
Abstract
The anorexigenic neuromodulator alpha-melanocyte-stimulating hormone (alpha-MSH; referred to here as alpha-MSH1-13) undergoes extensive posttranslational processing, and its in vivo activity is short lived due to rapid inactivation. The enzymatic control of alpha-MSH1-13 maturation and inactivation is incompletely understood. Here we have provided insight into alpha-MSH1-13 inactivation through the generation and analysis of a subcongenic mouse strain with reduced body fat compared with controls. Using positional cloning, we identified a maximum of 6 coding genes, including that encoding prolylcarboxypeptidase (PRCP), in the donor region. Real-time PCR revealed a marked genotype effect on Prcp mRNA expression in brain tissue. Biochemical studies using recombinant PRCP demonstrated that PRCP removes the C-terminal amino acid of alpha-MSH1-13, producing alpha-MSH1-12, which is not neuroactive. We found that Prcp was expressed in the hypothalamus in neuronal populations that send efferents to areas where alpha-MSH1-13 is released from axon terminals. The inhibition of PRCP activity by small molecule protease inhibitors administered peripherally or centrally decreased food intake in both wild-type and obese mice. Furthermore, Prcp-null mice had elevated levels of alpha-MSH1-13 in the hypothalamus and were leaner and shorter than the wild-type controls on a regular chow diet; they were also resistant to high-fat diet-induced obesity. Our results suggest that PRCP is an important component of melanocortin signaling and weight maintenance via control of active alpha-MSH1-13 levels.
Collapse
Affiliation(s)
- Nicholas Wallingford
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Yale University School of Medicine, New Haven, Connecticut, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
35
|
Garfield AS, Lam DD, Marston OJ, Przydzial MJ, Heisler LK. Role of central melanocortin pathways in energy homeostasis. Trends Endocrinol Metab 2009; 20:203-15. [PMID: 19541496 DOI: 10.1016/j.tem.2009.02.002] [Citation(s) in RCA: 105] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2008] [Revised: 02/06/2009] [Accepted: 02/06/2009] [Indexed: 02/07/2023]
Abstract
The rise in the global prevalence of human obesity has emphasized the need for a greater understanding of the physiological mechanisms that underlie energy homeostasis. Numerous circulating nutritional cues and central neuromodulatory signals are integrated within the brain to regulate both short- and long-term nutritional state. The central melanocortin system represents a crucial point of convergence for these signals and, thus, has a fundamental role in regulating body weight. The melanocortin ligands, synthesized in discrete neuronal populations within the hypothalamus and brainstem, modulate downstream homeostatic signalling via their action at central melanocortin-3 and -4 receptors. Intimately involved in both ingestive behaviour and energy expenditure, the melanocortin system has garnered much interest as a potential therapeutic target for human obesity.
Collapse
Affiliation(s)
- Alastair S Garfield
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1PD, UK
| | | | | | | | | |
Collapse
|
36
|
Rinne P, Harjunpää J, Scheinin M, Savontaus E. Blood pressure regulation and cardiac autonomic control in mice overexpressing alpha- and gamma-melanocyte stimulating hormone. Peptides 2008; 29:1943-52. [PMID: 18638516 DOI: 10.1016/j.peptides.2008.06.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2008] [Revised: 06/19/2008] [Accepted: 06/19/2008] [Indexed: 11/24/2022]
Abstract
Melanocyte stimulating hormones (MSH) derived from pro-opiomelanocortin have been demonstrated to participate in the central regulation of cardiovascular functions. The aim of the present study was to elucidate the chronic effects of increased melanocortin activation on blood pressure regulation and autonomic nervous system function. We adapted telemetry to transgenic mice overexpressing alpha- and gamma-MSH and measured blood pressure, heart rate and locomotor activity, and analyzed heart rate variability (HRV) in the frequency-domain as well as baroreflex function by the sequence technique. Transgenic (MSH-OE) mice had increased systolic blood pressure but their heart rate was similar to wild-type (WT) controls. The 24-h mean of systolic blood pressure was 132+/-7mmHg in MSH-OE and 113+/-4mmHg in WT mice. Locomotor activity was decreased in the MSH-OE mice. Furthermore, MSH-OE mice showed slower adaptation to mild environmental stress in terms of blood pressure changes. The low frequency (LF) power of HRV tended to be higher in MSH-OE mice compared to WT mice, without a difference in overall variability. The assessment of baroreflex function indicated enhanced baroreflex effectiveness and more frequent baroreflex operations in MSH-OE mice. Baseline heart rate, increased LF power of HRV and increased baroreflex activity may all reflect maintenance of baroreflex integrity and an increase in cardiac vagal activity to counteract the increased blood pressure. These results provide new evidence that long-term activation of the melanocortin system elevates blood pressure without increasing heart rate.
Collapse
Affiliation(s)
- Petteri Rinne
- Institute of Biomedicine, Department of Pharmacology, Drug Development and Therapeutics, University of Turku, Turku, Finland
| | | | | | | |
Collapse
|
37
|
Tiesjema B, Merkestein M, Garner KM, de Krom M, Adan RAH. Multimeric α-MSH has increased efficacy to activate the melanocortin MC4 receptor. Eur J Pharmacol 2008; 585:24-30. [PMID: 18378226 DOI: 10.1016/j.ejphar.2008.02.046] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2007] [Revised: 02/11/2008] [Accepted: 02/12/2008] [Indexed: 11/19/2022]
Affiliation(s)
- Birgitte Tiesjema
- Rudolf Magnus Institute of Neuroscience, Department of Neuroscience and Pharmacology, University Medical Center Utrecht, The Netherlands
| | | | | | | | | |
Collapse
|
38
|
Bays HE, González-Campoy JM, Bray GA, Kitabchi AE, Bergman DA, Schorr AB, Rodbard HW, Henry RR. Pathogenic potential of adipose tissue and metabolic consequences of adipocyte hypertrophy and increased visceral adiposity. Expert Rev Cardiovasc Ther 2008; 6:343-68. [PMID: 18327995 DOI: 10.1586/14779072.6.3.343] [Citation(s) in RCA: 334] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
When caloric intake exceeds caloric expenditure, the positive caloric balance and storage of energy in adipose tissue often causes adipocyte hypertrophy and visceral adipose tissue accumulation. These pathogenic anatomic abnormalities may incite metabolic and immune responses that promote Type 2 diabetes mellitus, hypertension and dyslipidemia. These are the most common metabolic diseases managed by clinicians and are all major cardiovascular disease risk factors. 'Disease' is traditionally characterized as anatomic and physiologic abnormalities of an organ or organ system that contributes to adverse health consequences. Using this definition, pathogenic adipose tissue is no less a disease than diseases of other body organs. This review describes the consequences of pathogenic fat cell hypertrophy and visceral adiposity, emphasizing the mechanistic contributions of genetic and environmental predispositions, adipogenesis, fat storage, free fatty acid metabolism, adipocyte factors and inflammation. Appreciating the full pathogenic potential of adipose tissue requires an integrated perspective, recognizing the importance of 'cross-talk' and interactions between adipose tissue and other body systems. Thus, the adverse metabolic consequences that accompany fat cell hypertrophy and visceral adiposity are best viewed as a pathologic partnership between the pathogenic potential adipose tissue and the inherited or acquired limitations and/or impairments of other body organs. A better understanding of the physiological and pathological interplay of pathogenic adipose tissue with other organs and organ systems may assist in developing better strategies in treating metabolic disease and reducing cardiovascular disease risk.
Collapse
Affiliation(s)
- Harold E Bays
- L-MARC Research Center, 3288 Illinois Avenue, Louisville, KY 40213, USA.
| | | | | | | | | | | | | | | |
Collapse
|
39
|
Disruption of the RIIbeta subunit of PKA reverses the obesity syndrome of Agouti lethal yellow mice. Proc Natl Acad Sci U S A 2008; 105:276-81. [PMID: 18172198 DOI: 10.1073/pnas.0710607105] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Agouti lethal yellow (A(y)) mice express agouti ectopically because of a genetic rearrangement at the agouti locus. The agouti peptide is a potent antagonist of the melanocortin 4 receptor (MC4R) expressed in neurons, and this leads to hyperphagia, hypoactivity, and increased fat mass. The MC4R signals through Gs and is thought to stimulate the production of cAMP and activation of downstream cAMP effector molecules such as PKA. Disruption of the RIIbeta regulatory subunit gene of PKA results in release of the active catalytic subunit and an increase in basal PKA activity in cells where RIIbeta is highly expressed. Because RIIbeta is expressed in neurons including those in the hypothalamic nuclei where MC4R is prominent we tested the possibility that the RIIbeta knockout might rescue the body weight phenotypes of the A(y) mice. Disruption of the RIIbeta PKA regulatory subunit gene in mice leads to a 50% reduction in white adipose tissue and resistance to diet-induced obesity and hyperglycemia. The RIIbeta mutation rescued the elevated body weight, hyperphagia, and obesity of A(y) mice. Partial rescue of the A(y) phenotypes was even observed on an RIIbeta heterozygote background. These results suggest that the RIIbeta gene mutation alters adiposity and locomotor activity by modifying PKA signaling pathways downstream of the agouti antagonism of MC4R in the hypothalamus.
Collapse
|
40
|
Coll AP. Effects of pro-opiomelanocortin (POMC) on food intake and body weight: mechanisms and therapeutic potential? Clin Sci (Lond) 2007; 113:171-82. [PMID: 17623013 DOI: 10.1042/cs20070105] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
POMC (pro-opiomelanocortin) is a complex polypeptide precursor which is cleaved into smaller biologically active peptides such as the melanocortins, α-, β- and γ-melanocyte-stimulating hormone. Data from human genetic and murine studies convincingly show that an intact central melanocortin signalling pathway is critical for normal energy homoeostasis. Not only does a loss of normal melanocortin signalling lead to obesity, but there are also data implicating increased melanocortin activity in the pathogenesis of cachexia. The study of POMC biology has lead to some fundamental insights into the mechanisms controlling food intake and body weight. This increased understanding of the physiological roles of the melanocortin system has opened up the potential for the design and development of rational therapies to treat perturbations in energy homoeostasis.
Collapse
Affiliation(s)
- Anthony P Coll
- Department of Clinical Biochemistry, Cambridge Institute for Medical Research, Addenbrooke's Hospital, Cambridge, UK.
| |
Collapse
|
41
|
Li G, Zhang Y, Cheng KY, Scarpace PJ. Lean rats with hypothalamic pro-opiomelanocortin overexpression exhibit greater diet-induced obesity and impaired central melanocortin responsiveness. Diabetologia 2007; 50:1490-9. [PMID: 17505816 DOI: 10.1007/s00125-007-0685-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2007] [Accepted: 03/15/2007] [Indexed: 11/26/2022]
Abstract
AIMS/HYPOTHESIS Central pro-opiomelanocortin (Pomc) gene therapy ameliorates genetic- or age-related obesity. We hypothesised that this treatment would delay or prevent dietary obesity in young, lean rats. MATERIALS AND METHODS Recombinant adeno-associated virus encoding Pomc (rAAV-Pomc) was delivered bilaterally into the basomedial hypothalamus of lean rats for 42 days. Food intake, body weight, serum hormones, brown adipose tissue (BAT) uncoupling protein 1 (UCP1) and mRNA levels of hypothalamic neuropeptides and melanocortin receptors were assessed. Beginning on day 43, half of the rats remained on chow while the others received a high-fat diet for 89 days. We examined energy balance and responsiveness to the melanocortin agonist melanotan II (MTII) or the antagonist SHU9119. RESULTS Pomc gene delivery produced elevated hypothalamic Pomc mRNA (fourfold) and alpha-melanocyte-stimulating hormone levels in the arcuate nucleus (twofold). Food intake and body weight were not altered by rAAV-Pomc in rats fed standard-chow. In rAAV-Pomc rats at day 42, perirenal fat and serum leptin decreased but overall visceral adiposity did not; expression of the hypothalamic agouti-related protein (Agrp) mRNA was elevated, whereas expression of melanocortin 3 and 4 receptor mRNA was reduced; BAT UCP1 protein increased nearly fourfold. The rAAV-Pomc rats fed the high-fat diet consumed more energy and gained more body weight compared with chow- or high-fat-fed controls that did not receive Pomc gene delivery. The anorexic response to MTII was impaired, whereas the orexigenic effect of SHU9119 was enhanced by rAAV-Pomc pretreatment. CONCLUSIONS/INTERPRETATION Delivery of the Pomc gene alters energy homeostasis in lean rats, predisposing them to diet-induced obesity. Diminished hypothalamic melanocortin receptors, increased Agrp expression, and potential rewiring of brain circuits may underlie the exacerbated obesity.
Collapse
Affiliation(s)
- G Li
- Department of Pharmacology and Therapeutics, University of Florida College of Medicine, Box 100267, Gainesville, FL 32610, USA
| | | | | | | |
Collapse
|
42
|
Lee M, Kim A, Chua SC, Obici S, Wardlaw SL. Transgenic MSH overexpression attenuates the metabolic effects of a high-fat diet. Am J Physiol Endocrinol Metab 2007; 293:E121-31. [PMID: 17374695 DOI: 10.1152/ajpendo.00555.2006] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
To determine whether long-term melanocortinergic activation can attenuate the metabolic effects of a high fat diet, mice overexpressing an NH(2)-terminal POMC transgene that includes alpha- and gamma(3)-MSH were studied on either a 10% low-fat diet (LFD) or 45% high-fat diet (HFD). Weight gain was modestly reduced in transgenic (Tg-MSH) male and female mice vs. wild type (WT) on HFD (P < 0.05) but not LFD. Substantial reductions in body fat percentage were found in both male and female Tg-MSH mice on LFD (P < 0.05) and were more pronounced on HFD (P < 0.001). These changes occurred in the absence of significant feeding differences in most groups, consistent with effects of Tg-MSH on energy expenditure and partitioning. This is supported by indirect calorimetry studies demonstrating higher resting oxygen consumption and lower RQ in Tg-MSH mice on the HFD. Tg-MSH mice had lower fasting insulin levels and improved glucose tolerance on both diets. Histological and biochemical analyses revealed that hepatic fat accumulation was markedly reduced in Tg-MSH mice on the HFD. Tg-MSH also attenuated the increase in corticosterone induced by the HFD. Higher levels of Agrp mRNA, which might counteract effects of the transgene, were measured in Tg-MSH mice on LFD (P = 0.02) but not HFD. These data show that long-term melanocortin activation reduces body weight, adiposity, and hepatic fat accumulation and improves glucose metabolism, particularly in the setting of diet-induced obesity. Our results suggest that long-term melanocortinergic activation could serve as a potential strategy for the treatment of obesity and its deleterious metabolic consequences.
Collapse
Affiliation(s)
- Michelle Lee
- Department of Medicine, Columbia University College of Physicians and Surgeons, 630 West 168th St., New York, NY 10032, USA
| | | | | | | | | |
Collapse
|
43
|
Li G, Zhang Y, Wilsey JT, Scarpace PJ. Hypothalamic pro-opiomelanocortin gene delivery ameliorates obesity and glucose intolerance in aged rats. Diabetologia 2005; 48:2376-85. [PMID: 16205885 DOI: 10.1007/s00125-005-1943-8] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2005] [Accepted: 06/20/2005] [Indexed: 10/25/2022]
Abstract
AIMS/HYPOTHESIS Age-related obesity is associated with impaired hypothalamic pro-opiomelanocortin (Pomc) gene expression. We assessed whether overproduction of POMC in the hypothalamus ameliorates age-related obesity in rats. METHODS Recombinant adeno-associated virus (rAAV) encoding Pomc (rAAV-Pomc) or control vector was delivered bilaterally into the basomedial hypothalamus of aged obese rats with coordinates targeting the arcuate nucleus. Energy balance, glucose metabolism, brown adipose tissue thermogenesis and mRNA levels of hypothalamic neuropeptides and melanocortin receptors were assessed. RESULTS Forty-two days after Pomc gene delivery, hypothalamic Pomc expression increased 12-fold while agouti-related protein and neuropeptide Y mRNA levels remained unchanged. Using a punch technique, we detected the highest Pomc RNA level in the arcuate nucleus. Pomc overexpression reduced food consumption from day 10 after vector injection, but this anorexic effect abated by day 30. In contrast, there was a steady decrease in body weight without apparent attenuation. Pomc gene delivery decreased visceral adiposity and induced uncoupling protein 1 in brown adipose tissue in aged rats. Serum NEFA and triglyceride levels were also diminished by rAAV-Pomc treatment. Improved glucose metabolism and insulin sensitivity were observed on day 36 but not day 20 after Pomc gene delivery. The expression of hypothalamic melanocortin 3 and 4 receptor decreased by 17% and 25%, respectively in rAAV-Pomc rats. CONCLUSIONS/INTERPRETATION This study demonstrates that targeted Pomc gene therapy in the hypothalamus reduces body weight and visceral adiposity, and improves glucose and fat metabolism in aged obese rats. Thus long-term activation of the central melanocortin system may be a viable strategy to combat age-related obesity and diabetes.
Collapse
MESH Headings
- Adipose Tissue, Brown/drug effects
- Adipose Tissue, Brown/metabolism
- Aging/physiology
- Agouti-Related Protein
- Animals
- Body Weight/genetics
- Cholesterol/blood
- Dependovirus/genetics
- Eating
- Fatty Acids, Nonesterified/blood
- Genetic Therapy/methods
- Genetic Vectors/genetics
- Genetic Vectors/pharmacology
- Glucose/metabolism
- Glucose Intolerance/genetics
- Glucose Tolerance Test/methods
- Hypothalamus/drug effects
- Intercellular Signaling Peptides and Proteins
- Leptin/blood
- Male
- Neuropeptide Y/drug effects
- Neuropeptide Y/genetics
- Obesity/genetics
- Obesity/metabolism
- Obesity/therapy
- Peptide Hormones/drug effects
- Peptide Hormones/genetics
- Pro-Opiomelanocortin/administration & dosage
- Pro-Opiomelanocortin/genetics
- Rats
- Rats, Inbred F344
- Receptor, Melanocortin, Type 3/drug effects
- Receptor, Melanocortin, Type 3/genetics
- Receptor, Melanocortin, Type 4/drug effects
- Receptor, Melanocortin, Type 4/genetics
- Triglycerides/blood
Collapse
Affiliation(s)
- G Li
- Department of Pharmacology and Therapeutics, University of Florida College of Medicine, Gainesville, FL, USA
| | | | | | | |
Collapse
|
44
|
Coll AP, Challis BG, López M, Piper S, Yeo GSH, O'Rahilly S. Proopiomelanocortin-deficient mice are hypersensitive to the adverse metabolic effects of glucocorticoids. Diabetes 2005; 54:2269-76. [PMID: 16046291 DOI: 10.2337/diabetes.54.8.2269] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Congenital lack of proopiomelanocortin (POMC) causes obesity and glucocorticoid deficiency. The responses of Pomc-/- and wild-type mice to the administration of corticosterone were compared. In study 1, mice were given corticosterone-supplemented water (CORT) for 10 days, resulting in plasma CORT levels within the physiological range, with partial suppression of hypothalamic corticotropin-releasing hormone expression to a similar degree between genotypes. Body weight, fat mass, and food intake increased in CORT-treated Pomc-/- but not wild-type mice. CORT increased plasma insulin levels 50-fold in Pomc-/- versus 14-fold in wild-type mice (P < 0.01) and increased hypothalamic agouti-related protein (AgRP) expression by more than 200% in Pomc-/- versus 40% in wild type (P < 0.05). In study 2, mice were given CORT from weaning, and Pomc-/- but not wild-type mice developed hyperglycemia, ketonuria, and hepatic steatosis by 8-12 weeks. Thus, Pomc-/- mice are hypersensitive to the adverse metabolic effects of glucocorticoids. Additionally, as the levels of plasma CORT achieved, especially in study 1, were not grossly supraphysiological, we conclude that glucocorticoid deficiency may afford Pomc-/- mice some protection from the full adverse consequences of melanocortin deficiency. This may occur through a mechanism involving the suppression of AgRP by the hypoadrenal state.
Collapse
Affiliation(s)
- Anthony P Coll
- University Department of Medicine,Addenbrooke's Hospital, Cambridge CB2 2QR, UK
| | | | | | | | | | | |
Collapse
|
45
|
|