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Obstructive Sleep Apnea, Circadian Clock Disruption, and Metabolic Consequences. Metabolites 2022; 13:metabo13010060. [PMID: 36676985 PMCID: PMC9863434 DOI: 10.3390/metabo13010060] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 12/26/2022] [Accepted: 12/27/2022] [Indexed: 01/03/2023] Open
Abstract
Obstructive sleep apnea (OSA) is a chronic disorder characterized by recurrent episodes of apnea and hypopnea during sleep. It is associated with various cardiovascular and metabolic complications, including type 2 diabetes mellitus (T2DM) and obesity. Many pathways can be responsible for T2DM development in OSA patients, e.g., those related to HIF-1 and SIRT1 expression. Moreover, epigenetic mechanisms, such as miRNA181a or miRNA199, are postulated to play a pivotal role in this link. It has been proven that OSA increases the occurrence of circadian clock disruption, which is also a risk factor for metabolic disease development. Circadian clock disruption impairs the metabolism of glucose, lipids, and the secretion of bile acids. Therefore, OSA-induced circadian clock disruption may be a potential, complex, underlying pathway involved in developing and exacerbating metabolic diseases among OSA patients. The current paper summarizes the available information pertaining to the relationship between OSA and circadian clock disruption in the context of potential mechanisms leading to metabolic disorders.
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Jamoussi Kamoun H, Hedfi I, Ben Amor N, Berriche O, Boumefteh S, Jarraya H, Nouira R, Mahjoub F. Évolution du syndrome métabolique après sleeve gastrectomie chez un groupe d’obèses tunisiens. NUTR CLIN METAB 2021. [DOI: 10.1016/j.nupar.2020.11.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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Suazo KF, Park KY, Distefano MD. A Not-So-Ancient Grease History: Click Chemistry and Protein Lipid Modifications. Chem Rev 2021; 121:7178-7248. [PMID: 33821625 PMCID: PMC8820976 DOI: 10.1021/acs.chemrev.0c01108] [Citation(s) in RCA: 69] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Protein lipid modification involves the attachment of hydrophobic groups to proteins via ester, thioester, amide, or thioether linkages. In this review, the specific click chemical reactions that have been employed to study protein lipid modification and their use for specific labeling applications are first described. This is followed by an introduction to the different types of protein lipid modifications that occur in biology. Next, the roles of click chemistry in elucidating specific biological features including the identification of lipid-modified proteins, studies of their regulation, and their role in diseases are presented. A description of the use of protein-lipid modifying enzymes for specific labeling applications including protein immobilization, fluorescent labeling, nanostructure assembly, and the construction of protein-drug conjugates is presented next. Concluding remarks and future directions are presented in the final section.
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Affiliation(s)
- Kiall F. Suazo
- Department of Chemistry, University of Minnesota, Minneapolis, MN 55455 USA
| | - Keun-Young Park
- Department of Chemistry, University of Minnesota, Minneapolis, MN 55455 USA
| | - Mark D. Distefano
- Department of Chemistry, University of Minnesota, Minneapolis, MN 55455 USA
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Su M, Yan M, Yao J, Fang Y, Jin H, Gong Y. Unacylated Ghrelin Regulates Glucose-Sensitive Neurons Activity and Glycolipid Metabolism via Orexin-A Neurons in the Lateral Hypothalamic Area. Horm Metab Res 2020; 52:747-754. [PMID: 32731263 DOI: 10.1055/a-1207-1212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The objective of the study was to investigate the regulatory actions of unacylated ghrelin (UAG) on glucose-sensitive (GS) neurons and glycolipid metabolism in the lateral hypothalamus area (LHA) and its involvement with orexin-A-immunopositive neurons. The effects of UAG administered into the LHA on GS neurons discharges and glycolipid metabolism were detected by single neuron discharge recording, biochemical index analysis and quantitative real-time PCR; the level of c-fos protein in orexin-A-immunopositive neurons was observed using immunofluorescence staining. UAG microinjected into the LHA activated glucose-inhibited neurons, which were partially blocked by pre-administration of anti-orexin-A antibody in the LHA. Furthermore, UAG microinjected into the LHA significantly reduced serum triglycerides (TG), total cholesterol, low-density lipoprotein cholesterol, blood glucose, insulin and hepatic TG levels, while elevated serum high-density lipoprotein cholesterol levels. UAG elevated the mRNA expression of carnitine palmitoyltransferase-1 and reduced the mRNA expression of acetyl-CoA carboxylase-1 in the liver. The above-mentioned effects of UAG were partially blocked by pre-administration of anti-orexin-A antibody. The expressions of orexin-A and c-fos were observed in the LHA. After UAG injection into the LHA, some neurons showed double labeling, and the percentage of double-labeled orexin-A/c-fos neurons in orexin-A-immunopositive neurons increased significantly. UAG in the LHA regulates glycolipid metabolism by activating orexin-A-immunopositive neurons in the LHA.
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Affiliation(s)
- Manqing Su
- Department of Pharmacy, College of Chemical Engineering, Qingdao University of Science and Technology, Qingdao, China
| | - Meixing Yan
- Qingdao Women and Children's Hospital, Qingdao, China
| | - Jiatong Yao
- Department of Pharmacy, College of Chemical Engineering, Qingdao University of Science and Technology, Qingdao, China
| | - Yanpeng Fang
- Department of Pharmacy, College of Chemical Engineering, Qingdao University of Science and Technology, Qingdao, China
| | - Hong Jin
- Department of Pharmacy, College of Chemical Engineering, Qingdao University of Science and Technology, Qingdao, China
| | - Yanling Gong
- Department of Pharmacy, College of Chemical Engineering, Qingdao University of Science and Technology, Qingdao, China
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EFSA Panel on Contaminants in the Food Chain (CONTAM), Schrenk D, Bignami M, Bodin L, Chipman JK, del Mazo J, Hogstrand C, Hoogenboom L(R, Leblanc J, Nebbia CS, Nielsen E, Ntzani E, Petersen A, Sand S, Schwerdtle T, Vleminckx C, Wallace H, Brimer L, Cottrill B, Dusemund B, Mulder P, Vollmer G, Binaglia M, Ramos Bordajandi L, Riolo F, Roldán‐Torres R, Grasl‐Kraupp B. Risk assessment of glycoalkaloids in feed and food, in particular in potatoes and potato-derived products. EFSA J 2020; 18:e06222. [PMID: 32788943 PMCID: PMC7417869 DOI: 10.2903/j.efsa.2020.6222] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The European Commission asked EFSA for a scientific opinion on the risks for animal and human health related to the presence of glycoalkaloids (GAs) in feed and food. This risk assessment covers edible parts of potato plants and other food plants containing GAs, in particular, tomato and aubergine. In humans, acute toxic effects of potato GAs (α-solanine and α-chaconine) include gastrointestinal symptoms such as nausea, vomiting and diarrhoea. For these effects, the CONTAM Panel identified a lowest-observed-adverse-effect level of 1 mg total potato GAs/kg body weight (bw) per day as a reference point for the risk characterisation following acute exposure. In humans, no evidence of health problems associated with repeated or long-term intake of GAs via potatoes has been identified. No reference point for chronic exposure could be identified from the experimental animal studies. Occurrence data were available only for α-solanine and α-chaconine, mostly for potatoes. The acute dietary exposure to potato GAs was estimated using a probabilistic approach and applying processing factors for food. Due to the limited data available, a margin of exposure (MOE) approach was applied. The MOEs for the younger age groups indicate a health concern for the food consumption surveys with the highest mean exposure, as well as for the P95 exposure in all surveys. For adult age groups, the MOEs indicate a health concern only for the food consumption surveys with the highest P95 exposures. For tomato and aubergine GAs, the risk to human health could not be characterised due to the lack of occurrence data and the limited toxicity data. For horses, farm and companion animals, no risk characterisation for potato GAs could be performed due to insufficient data on occurrence in feed and on potential adverse effects of GAs in these species.
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Tian P, Lu X, Jin N, Shi J. Knockdown of ghrelin-O-acyltransferase attenuates colitis through the modulation of inflammatory factors and tight junction proteins in the intestinal epithelium. Cell Biol Int 2020; 44:1681-1690. [PMID: 32281710 DOI: 10.1002/cbin.11362] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Revised: 04/03/2020] [Accepted: 04/11/2020] [Indexed: 12/13/2022]
Abstract
Ghrelin-O-acyltransferase (GOAT) is a membrane-bound enzyme that attaches eight-carbon octanoate to a serine residue in ghrelin and thereby acylates inactive ghrelin to produce active ghrelin. In this study, we investigated the function of GOAT in the intestinal mucosal barrier. The intestinal mucosal barrier prevents harmful substances such as bacteria and endotoxin from entering the other tissues, organs, and blood circulation through the intestinal mucosa. Here, we established 5% dextran sodium sulfate (DSS)-induced colitis in mice and found that the body weight and colon weight were significantly decreased in these mice. Furthermore, increased inflammation and apoptosis were observed in the tissues of DSS-induced colitis mice, with increased expression of tumor necrosis factor-α, interleukin-6, phosphorylation of nuclear factor kappa B-p65 (p-NF-κB-p65), and cleaved caspase-3, and decreased expression of tight junction (TJ) proteins such as zonula occluden-1 and occludin. The knockdown of GOAT significantly attenuated colitis-induced inflammation responses and apoptosis, while GOAT overexpression significantly enhanced the induction of colitis. These results suggest that knockdown of GOAT may attenuate colitis-induced inflammation, ulcers, and fecal occult blood by decreasing the intestinal mucosal permeability via the modulation of inflammatory factors and TJ proteins.
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Affiliation(s)
- Peiying Tian
- Department of Digestion, Shanghai Pudong Hospital, Shanghai, China
| | - Xiaolan Lu
- Department of Digestion, Shanghai Pudong Hospital, Shanghai, China
| | - Nuyun Jin
- Department of Digestion, Shanghai Pudong Hospital, Shanghai, China
| | - Jianping Shi
- Department of Digestion, Shanghai Pudong Hospital, Shanghai, China
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Characterization of Ghrelin O-Acyltransferase (GOAT) in goldfish (Carassius auratus). PLoS One 2017; 12:e0171874. [PMID: 28178327 PMCID: PMC5298278 DOI: 10.1371/journal.pone.0171874] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Accepted: 01/26/2017] [Indexed: 12/21/2022] Open
Abstract
Ghrelin is the only known hormone posttranslationally modified with an acylation. This modification is crucial for most of ghrelin’s physiological effects and is catalyzed by the polytopic enzyme ghrelin O-acyltransferase (GOAT). The aim of this study was to characterize GOAT in a teleost model, goldfish (Carassius auratus). First, the full-length cDNA sequence was obtained by RT-PCR and rapid amplification of cDNA ends methods. Two highly homologous cDNAs of 1491 and 1413 bp, respectively, named goat-V1 and goat-V2 were identified. Deduced protein sequences (393 and 367 amino acids, respectively) are predicted to present 11 and 9 transmembrane regions, respectively, and both contain two conserved key residues proposed to be involved in catalysis: asparagine 273 and histidine 304. RT-qPCR revealed that both forms of goat mRNAs show a similar widespread tissue distribution, with the highest expression in the gastrointestinal tract and gonads and less but considerable expression in brain, pituitary, liver and adipose tissue. Immunostaining of intestinal sections showed the presence of GOAT immunoreactive cells in the intestinal mucosa, some of which colocalize with ghrelin. Using an in vitro approach, we observed that acylated ghrelin downregulates GOAT gene and protein levels in cultured intestine in a time-dependent manner. Finally, we found a rhythmic oscillation of goat mRNA expression in the hypothalamus, pituitary and intestinal bulb of goldfish fed at midday, but not at midnight. Together, these findings report novel data characterizing GOAT, and offer new information about the ghrelinergic system in fish.
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McGovern-Gooch KR, Mahajani NS, Garagozzo A, Schramm AJ, Hannah LG, Sieburg MA, Chisholm JD, Hougland JL. Synthetic Triterpenoid Inhibition of Human Ghrelin O-Acyltransferase: The Involvement of a Functionally Required Cysteine Provides Mechanistic Insight into Ghrelin Acylation. Biochemistry 2017; 56:919-931. [PMID: 28134508 DOI: 10.1021/acs.biochem.6b01008] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The peptide hormone ghrelin plays a key role in regulating hunger and energy balance within the body. Ghrelin signaling presents a promising and unexploited target for development of small molecule therapeutics for treatment of obesity, diabetes, and other health conditions. Inhibition of ghrelin O-acyltransferase (GOAT), which catalyzes an essential octanoylation step in ghrelin maturation, offers a potential avenue for controlling ghrelin signaling. Through screening a small molecule library, we have identified a class of synthetic triterpenoids that efficiently inhibit ghrelin acylation by the human isoform of GOAT (hGOAT). These compounds function as covalent reversible inhibitors of hGOAT, providing the first evidence of the involvement of a nucleophilic cysteine residue in substrate acylation by a MBOAT family acyltransferase. Surprisingly, the mouse form of GOAT does not exhibit susceptibility to cysteine-modifying electrophiles, revealing an important distinction in the activity and behavior between these closely related GOAT isoforms. This study establishes these compounds as potent small molecule inhibitors of ghrelin acylation and provides a foundation for the development of novel hGOAT inhibitors as therapeutics targeting diabetes and obesity.
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Affiliation(s)
| | - Nivedita S Mahajani
- Department of Chemistry, Syracuse University , Syracuse, New York 13244, United States
| | - Ariana Garagozzo
- Department of Chemistry, Syracuse University , Syracuse, New York 13244, United States
| | - Anthony J Schramm
- Department of Chemistry, Syracuse University , Syracuse, New York 13244, United States
| | - Lauren G Hannah
- Department of Chemistry, Syracuse University , Syracuse, New York 13244, United States
| | - Michelle A Sieburg
- Department of Chemistry, Syracuse University , Syracuse, New York 13244, United States
| | - John D Chisholm
- Department of Chemistry, Syracuse University , Syracuse, New York 13244, United States
| | - James L Hougland
- Department of Chemistry, Syracuse University , Syracuse, New York 13244, United States
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Chacrabati R, Gong Z, Ikenoya C, Kondo D, Zigman JM, Sakai T, Sakata I. The effect of glutamate on ghrelin release in mice. Cell Biol Int 2017; 41:320-327. [DOI: 10.1002/cbin.10728] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Accepted: 12/30/2016] [Indexed: 12/14/2022]
Affiliation(s)
- Rakhi Chacrabati
- Area of Regulatory Biology; Division of Life Science; Graduate School of Science and Engineering; Saitama University; 255 Shimo-ohkubo Sakuraku Saitama 338-8570 Japan
| | - Zhi Gong
- Area of Regulatory Biology; Division of Life Science; Graduate School of Science and Engineering; Saitama University; 255 Shimo-ohkubo Sakuraku Saitama 338-8570 Japan
| | - Chika Ikenoya
- Area of Regulatory Biology; Division of Life Science; Graduate School of Science and Engineering; Saitama University; 255 Shimo-ohkubo Sakuraku Saitama 338-8570 Japan
| | - Daisuke Kondo
- Area of Regulatory Biology; Division of Life Science; Graduate School of Science and Engineering; Saitama University; 255 Shimo-ohkubo Sakuraku Saitama 338-8570 Japan
| | - Jeffrey M. Zigman
- Departments of Internal Medicine (Divisions of Hypothalamic Research and Endocrinology & Metabolism) and Psychiatry; University of Texas Southwestern Medical Center; 5323 Harry Hines Blvd Dallas TX 75390-9077 USA
| | - Takafumi Sakai
- Area of Life-NanoBio, Division of Strategy, Graduate School of Science and Engineering; Saitama University; 255 Shimo-ohkubo Sakuraku Saitama 338-8570 Japan
| | - Ichiro Sakata
- Area of Regulatory Biology; Division of Life Science; Graduate School of Science and Engineering; Saitama University; 255 Shimo-ohkubo Sakuraku Saitama 338-8570 Japan
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Hormaechea-Agulla D, Gómez-Gómez E, Ibáñez-Costa A, Carrasco-Valiente J, Rivero-Cortés E, L-López F, Pedraza-Arevalo S, Valero-Rosa J, Sánchez-Sánchez R, Ortega-Salas R, Moreno MM, Gahete MD, López-Miranda J, Requena MJ, Castaño JP, Luque RM. Ghrelin O-acyltransferase (GOAT) enzyme is overexpressed in prostate cancer, and its levels are associated with patient's metabolic status: Potential value as a non-invasive biomarker. Cancer Lett 2016; 383:125-134. [PMID: 27693462 DOI: 10.1016/j.canlet.2016.09.022] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2016] [Revised: 09/01/2016] [Accepted: 09/02/2016] [Indexed: 12/31/2022]
Abstract
Ghrelin-O-acyltransferase (GOAT) is the key enzyme regulating ghrelin activity, and has been proposed as a potential therapeutic target for obesity/diabetes and as a biomarker in some endocrine-related cancers. However, GOAT presence and putative role in prostate-cancer (PCa) is largely unknown. Here, we demonstrate, for the first time, that GOAT is overexpressed (mRNA/protein-level) in prostatic tissues (n = 52) and plasma/urine-samples (n = 85) of PCa-patients, compared with matched controls [healthy prostate tissues (n = 12) and plasma/urine-samples from BMI-matched controls (n = 28), respectively]. Interestingly, GOAT levels in PCa-patients correlated with aggressiveness and metabolic conditions (i.e. diabetes). Actually, GOAT expression was regulated by metabolic inputs (i.e. In1-ghrelin, insulin/IGF-I) in cultured normal prostate cells and PCa-cell lines. Importantly, ROC-curve analysis unveiled a valuable diagnostic potential for GOAT to discriminate PCa at the tissue/plasma/urine-level with high sensitivity/specificity, particularly in non-diabetic individuals. Moreover, we discovered that GOAT is secreted by PCa-cells, and that its levels are higher in urine samples from a stimulated post-massage vs. pre-massage prostate-test. In conclusion, plasmatic GOAT levels exhibit high specificity/sensitivity to predict PCa-presence compared with other PCa-biomarkers, especially in non-diabetic individuals, suggesting that GOAT holds potential as a novel non-invasive PCa-biomarker.
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Affiliation(s)
- Daniel Hormaechea-Agulla
- Maimonides Institute of Biomedical Research of Córdoba (IMIBIC), Córdoba, Spain; Department of Cell Biology, Physiology and Immunology, University of Córdoba, Córdoba, Spain; Hospital Universitario Reina Sofía (HURS), Córdoba, Spain; CIBERobn, Córdoba, Spain; ceiA3, Córdoba, Spain
| | - Enrique Gómez-Gómez
- Maimonides Institute of Biomedical Research of Córdoba (IMIBIC), Córdoba, Spain; Hospital Universitario Reina Sofía (HURS), Córdoba, Spain; Urology Service, HURS, Córdoba, Spain
| | - Alejandro Ibáñez-Costa
- Maimonides Institute of Biomedical Research of Córdoba (IMIBIC), Córdoba, Spain; Department of Cell Biology, Physiology and Immunology, University of Córdoba, Córdoba, Spain; Hospital Universitario Reina Sofía (HURS), Córdoba, Spain; CIBERobn, Córdoba, Spain; ceiA3, Córdoba, Spain
| | - Julia Carrasco-Valiente
- Maimonides Institute of Biomedical Research of Córdoba (IMIBIC), Córdoba, Spain; Hospital Universitario Reina Sofía (HURS), Córdoba, Spain; Urology Service, HURS, Córdoba, Spain
| | - Esther Rivero-Cortés
- Maimonides Institute of Biomedical Research of Córdoba (IMIBIC), Córdoba, Spain; Department of Cell Biology, Physiology and Immunology, University of Córdoba, Córdoba, Spain; Hospital Universitario Reina Sofía (HURS), Córdoba, Spain; CIBERobn, Córdoba, Spain; ceiA3, Córdoba, Spain
| | - Fernando L-López
- Maimonides Institute of Biomedical Research of Córdoba (IMIBIC), Córdoba, Spain; Department of Cell Biology, Physiology and Immunology, University of Córdoba, Córdoba, Spain; Hospital Universitario Reina Sofía (HURS), Córdoba, Spain; CIBERobn, Córdoba, Spain; ceiA3, Córdoba, Spain
| | - Sergio Pedraza-Arevalo
- Maimonides Institute of Biomedical Research of Córdoba (IMIBIC), Córdoba, Spain; Department of Cell Biology, Physiology and Immunology, University of Córdoba, Córdoba, Spain; Hospital Universitario Reina Sofía (HURS), Córdoba, Spain; CIBERobn, Córdoba, Spain; ceiA3, Córdoba, Spain
| | - José Valero-Rosa
- Maimonides Institute of Biomedical Research of Córdoba (IMIBIC), Córdoba, Spain; Hospital Universitario Reina Sofía (HURS), Córdoba, Spain; Urology Service, HURS, Córdoba, Spain
| | - Rafael Sánchez-Sánchez
- Maimonides Institute of Biomedical Research of Córdoba (IMIBIC), Córdoba, Spain; Hospital Universitario Reina Sofía (HURS), Córdoba, Spain; Anatomical Pathology Service, HURS, Córdoba, Spain
| | - Rosa Ortega-Salas
- Maimonides Institute of Biomedical Research of Córdoba (IMIBIC), Córdoba, Spain; Hospital Universitario Reina Sofía (HURS), Córdoba, Spain; Anatomical Pathology Service, HURS, Córdoba, Spain
| | - María M Moreno
- Maimonides Institute of Biomedical Research of Córdoba (IMIBIC), Córdoba, Spain; Hospital Universitario Reina Sofía (HURS), Córdoba, Spain; Anatomical Pathology Service, HURS, Córdoba, Spain
| | - Manuel D Gahete
- Maimonides Institute of Biomedical Research of Córdoba (IMIBIC), Córdoba, Spain; Department of Cell Biology, Physiology and Immunology, University of Córdoba, Córdoba, Spain; Hospital Universitario Reina Sofía (HURS), Córdoba, Spain; CIBERobn, Córdoba, Spain; ceiA3, Córdoba, Spain
| | - José López-Miranda
- Maimonides Institute of Biomedical Research of Córdoba (IMIBIC), Córdoba, Spain; Hospital Universitario Reina Sofía (HURS), Córdoba, Spain; CIBERobn, Córdoba, Spain; Lipids and Atherosclerosis Unit, HURS, Córdoba, Spain
| | - María J Requena
- Maimonides Institute of Biomedical Research of Córdoba (IMIBIC), Córdoba, Spain; Hospital Universitario Reina Sofía (HURS), Córdoba, Spain; Urology Service, HURS, Córdoba, Spain
| | - Justo P Castaño
- Maimonides Institute of Biomedical Research of Córdoba (IMIBIC), Córdoba, Spain; Department of Cell Biology, Physiology and Immunology, University of Córdoba, Córdoba, Spain; Hospital Universitario Reina Sofía (HURS), Córdoba, Spain; CIBERobn, Córdoba, Spain; ceiA3, Córdoba, Spain.
| | - Raúl M Luque
- Maimonides Institute of Biomedical Research of Córdoba (IMIBIC), Córdoba, Spain; Department of Cell Biology, Physiology and Immunology, University of Córdoba, Córdoba, Spain; Hospital Universitario Reina Sofía (HURS), Córdoba, Spain; CIBERobn, Córdoba, Spain; ceiA3, Córdoba, Spain.
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11
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Barazzoni R, Gortan Cappellari G, Semolic A, Ius M, Dore F, Giacca M, Zanetti M, Vinci P, Guarnieri G. Intravenous lipid infusion and total plasma fatty acids positively modulate plasma acylated ghrelin in vivo. Clin Nutr 2016; 36:775-781. [PMID: 27312085 DOI: 10.1016/j.clnu.2016.05.017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Revised: 04/20/2016] [Accepted: 05/26/2016] [Indexed: 11/26/2022]
Abstract
BACKGROUND & AIMS Ghrelin is a gastric orexigenic hormone whose activating acylation plays a relevant role in the regulation of energy balance. Nutritional modulators of ghrelin acylation and plasma acylated ghrelin (AG) concentration remain however largely undefined. We aimed at investigating whether circulating free fatty acids (FFA) contribute to regulate plasma AG and its ratio (AG/TG) to total hormone (TG). METHODS Plasma FFA, TG, AG and AG/TG were measured in a primary outpatient care setting in a community-based population cohort of 850 individuals (age 54 ± 10 years, M/F: 408/442) from the North-East Italy MoMa study. 150-min intravenous lipid infusions in rodents (10% lipids, 600 μl/h) were used to investigate the potential causal role of FFA in the regulation of plasma ghrelin profile. RESULTS Plasma FFA were associated positively with AG and AG/TG while negatively with TG (P < 0.01). Associations between FFA, AG and AG/TG remained statistically significant (P < 0.02) in multiple regression analysis including HOMA insulin resistance and metabolic confounders, and both AG and AG/TG but not TG increased through plasma FFA quartiles (P < 0.01). Consistent with these findings, intravenous lipid infusion with plasma FFA elevation caused elevations of AG and AG/TG (P < 0.05) with no TG modifications. CONCLUSIONS The current findings demonstrate a novel role for circulating FFA availability to up-regulate plasma AG, which could involve FFA-induced stimulation of ghrelin acylation.
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Affiliation(s)
- R Barazzoni
- Dept. of Medical, Surgical and Health Sciences, University of Trieste, Italy.
| | - G Gortan Cappellari
- Dept. of Medical, Surgical and Health Sciences, University of Trieste, Italy
| | - A Semolic
- Dept. of Medical, Surgical and Health Sciences, University of Trieste, Italy
| | - M Ius
- Dept. of Medical, Surgical and Health Sciences, University of Trieste, Italy
| | - F Dore
- Dept of Nuclear Medicine, Azienda Ospedaliero-Universitaria Ospedali Riuniti, Trieste, Italy
| | - M Giacca
- Molecular Medicine Laboratory, International Centre for Genetics, Engineering and Biotechnology, Trieste, Italy
| | - M Zanetti
- Dept. of Medical, Surgical and Health Sciences, University of Trieste, Italy
| | - P Vinci
- Dept. of Medical, Surgical and Health Sciences, University of Trieste, Italy
| | - G Guarnieri
- Dept. of Medical, Surgical and Health Sciences, University of Trieste, Italy
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12
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Blanco AM, Sánchez-Bretaño A, Delgado MJ, Valenciano AI. Brain Mapping of Ghrelin O-Acyltransferase in Goldfish (Carassius Auratus): Novel Roles for the Ghrelinergic System in Fish? Anat Rec (Hoboken) 2016; 299:748-58. [PMID: 27064922 DOI: 10.1002/ar.23346] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Revised: 02/16/2016] [Accepted: 02/22/2016] [Indexed: 12/19/2022]
Abstract
Ghrelin O-acyltransferase (GOAT) is the enzyme responsible for acylation of ghrelin, a gut-brain hormone with important roles in many physiological functions in vertebrates. Many aspects of GOAT remain to be elucidated, especially in fish, and particularly its anatomical distribution within the different brain areas has never been reported to date. The present study aimed to characterize the brain mapping of GOAT using RT-qPCR and immunohistochemistry in a teleost, the goldfish (Carassius auratus). Results show that goat transcripts are expressed in different brain areas of the goldfish, with the highest levels in the vagal lobe. Using immunohistochemistry, we also report the presence of GOAT immunoreactive cells in different encephalic areas, including the telencephalon, some hypothalamic nuclei, pineal gland, optic tectum and cerebellum, although they are especially abundant in the hindbrain. Particularly, an important signal is observed in the vagal lobe and some fiber tracts of the brainstem, such as the medial longitudinal fasciculus, Mauthneri fasciculus, secondary gustatory tract and spinothalamic tract. Most of the forebrain areas where GOAT is detected, particularly the hypothalamic nuclei, also express the ghs-r1a ghrelin receptor and other appetite-regulating hormones (e.g., orexin and NPY), supporting the role of ghrelin as a modulator of food intake and energy balance in fish. Present results are the first report on the presence of GOAT in the brain using imaging techniques. The high presence of GOAT in the hindbrain is a novelty, and point to possible new functions for the ghrelinergic system in fish. Anat Rec, 299:748-758, 2016. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Ayelén M Blanco
- Department of Animal Physiology II, Faculty of Biology, Complutense University, Madrid, 28040, Spain
| | - Aída Sánchez-Bretaño
- Department of Animal Physiology II, Faculty of Biology, Complutense University, Madrid, 28040, Spain
| | - María J Delgado
- Department of Animal Physiology II, Faculty of Biology, Complutense University, Madrid, 28040, Spain
| | - Ana I Valenciano
- Department of Animal Physiology II, Faculty of Biology, Complutense University, Madrid, 28040, Spain
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Periprandial changes and effects of short- and long-term fasting on ghrelin, GOAT, and ghrelin receptors in goldfish (Carassius auratus). J Comp Physiol B 2016; 186:727-38. [DOI: 10.1007/s00360-016-0986-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Revised: 03/26/2016] [Accepted: 03/29/2016] [Indexed: 02/06/2023]
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Li G, Xia J, Jia P, Zhao J, Sun Y, Wu C, Liu B. Plasma Levels of Acylated Ghrelin in Children with Pulmonary Hypertension Associated with Congenital Heart Disease. Pediatr Cardiol 2015; 36:1423-8. [PMID: 25981561 DOI: 10.1007/s00246-015-1178-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Accepted: 04/28/2015] [Indexed: 12/29/2022]
Abstract
This study aims to estimate plasma levels of acylated ghrelin in children with pulmonary hypertension (PH) associated with congenital heart disease (CHD) and to correlate the levels of acylated ghrelin with endothelin-1 (ET-1), nitric oxide (NO), and clinical hemodynamic parameters. We investigated the plasma concentration of acylated ghrelin, ET-1, NO, and the hemodynamic parameters in 20 children with CHD, 20 children with PH-CHD, and 20 normal children. Plasma-acylated ghrelin and NO levels were significantly higher in CHD group than in control subjects (P < 0.001). Moreover, plasma-acylated ghrelin, ET-1, and NO levels were significantly elevated in PH-CHD group compared with the CHD group (P < 0.05). In PH-CHD children, plasma-acylated ghrelin levels correlated positively with pulmonary artery systolic pressure (PASP; r = 0.740, P < 0.001), pulmonary artery diastolic pressure (PADP; r = 0.613, P = 0.004), right ventricular systolic pressure (RVSP; r = 0.642, P = 0.002), mean pulmonary arterial hypertension (mPAP; r = 0.685, P = 0.001), right ventricle diameter (RVD; r = 0.473, P = 0.035), pulmonary artery trunk diameter (PAD; r = 0.613, P = 0.004), NO (r = 0.463, P = 0.04), and ET-1 (r = 0.524, P = 0.018). Plasma-acylated ghrelin levels were elevated both in CHD and in PH-CHD. Increased acylated ghrelin levels correlated positively with ET-1, NO, PASP, PADP, RVSP, mPAP, RVD, and PAD. Acylated ghrelin may be a new biomarker of PH-CHD.
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Affiliation(s)
- Gang Li
- Department of Pediatrics, The Affiliated Hospital of Luzhou Medical College, No. 25 Taiping Street, Luzhou, 646000, Sichuan, China
| | - Jiyi Xia
- Research Center for Drug and Functional Foods of Luzhou Medical College, Luzhou, 646000, Sichuan, China
| | - Peng Jia
- Department of Pediatrics, The Affiliated Hospital of Luzhou Medical College, No. 25 Taiping Street, Luzhou, 646000, Sichuan, China
| | - Jian Zhao
- Department of Pediatrics, The Affiliated Hospital of Luzhou Medical College, No. 25 Taiping Street, Luzhou, 646000, Sichuan, China
| | - Yuqin Sun
- Department of Pediatrics, The Affiliated Hospital of Luzhou Medical College, No. 25 Taiping Street, Luzhou, 646000, Sichuan, China
| | - Changxue Wu
- Department of Cardiothoracic Surgery, The Affiliated Hospital of Luzhou Medical College, Luzhou, 646000, Sichuan, China
| | - Bin Liu
- Department of Pediatrics, The Affiliated Hospital of Luzhou Medical College, No. 25 Taiping Street, Luzhou, 646000, Sichuan, China.
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Mosa RMH, Zhang Z, Shao R, Deng C, Chen J, Chen C. Implications of ghrelin and hexarelin in diabetes and diabetes-associated heart diseases. Endocrine 2015; 49:307-23. [PMID: 25645463 DOI: 10.1007/s12020-015-0531-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Accepted: 01/12/2015] [Indexed: 02/07/2023]
Abstract
Ghrelin and its synthetic analog hexarelin are specific ligands of growth hormone secretagogue (GHS) receptor. GHS have strong growth hormone-releasing effect and other neuroendocrine activities such as stimulatory effects on prolactin and adrenocorticotropic hormone secretion. Recently, several studies have reported other beneficial functions of GHS that are independent of GH. Ghrelin and hexarelin, for examples, have been shown to exert GH-independent cardiovascular activity. Hexarelin has been reported to regulate peroxisome proliferator-activated receptor gamma (PPAR-γ) in macrophages and adipocytes. PPAR-γ is an important regulator of adipogenesis, lipid metabolism, and insulin sensitization. Ghrelin also shows protective effects on beta cells against lipotoxicity through activation of phosphatidylinositol-3 kinase/protein kinase B, c-Jun N-terminal kinase (JNK) inhibition, and nuclear exclusion of forkhead box protein O1. Acylated ghrelin (AG) and unacylated ghrelin (UAG) administration reduces glucose levels and increases insulin-producing beta cell number, and insulin secretion in pancreatectomized rats and in newborn rats treated with streptozotocin, suggesting a possible role of GHS in pancreatic regeneration. Therefore, the discovery of GHS has opened many new perspectives in endocrine, metabolic, and cardiovascular research areas, suggesting the possible therapeutic application in diabetes and diabetic complications especially diabetic cardiomyopathy. Here, we review the physiological roles of ghrelin and hexarelin in the protection and regeneration of beta cells and their roles in the regulation of insulin release, glucose, and fat metabolism and present their potential therapeutic effects in the treatment of diabetes and diabetic-associated heart diseases.
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A new class of ghrelin O-acyltransferase inhibitors incorporating triazole-linked lipid mimetic groups. Bioorg Med Chem Lett 2015; 25:2800-3. [PMID: 26009163 DOI: 10.1016/j.bmcl.2015.05.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2015] [Revised: 05/04/2015] [Accepted: 05/06/2015] [Indexed: 02/06/2023]
Abstract
Inhibitors of ghrelin O-acyltransferase (GOAT) have untapped potential as therapeutics targeting obesity and diabetes. We report the first examples of GOAT inhibitors incorporating a triazole linkage as a biostable isosteric replacement for the ester bond in ghrelin and amide bonds in previously reported GOAT inhibitors. These triazole-containing inhibitors exhibit sub-micromolar inhibition of the human isoform of GOAT (hGOAT), and provide a foundation for rapid future chemical diversification and optimization of hGOAT inhibitors.
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Darling JE, Zhao F, Loftus RJ, Patton LM, Gibbs RA, Hougland JL. Structure–Activity Analysis of Human Ghrelin O-Acyltransferase Reveals Chemical Determinants of Ghrelin Selectivity and Acyl Group Recognition. Biochemistry 2015; 54:1100-10. [DOI: 10.1021/bi5010359] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Joseph E. Darling
- Department
of Chemistry, Syracuse University, Syracuse, New York 13244, United States
| | - Feifei Zhao
- Department
of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, Indiana 47907, United States
| | - Rosemary J. Loftus
- Department
of Chemistry, Syracuse University, Syracuse, New York 13244, United States
| | - Leslie M. Patton
- Department
of Chemistry, Syracuse University, Syracuse, New York 13244, United States
| | - Richard A. Gibbs
- Department
of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, Indiana 47907, United States
| | - James L. Hougland
- Department
of Chemistry, Syracuse University, Syracuse, New York 13244, United States
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Oiso S, Nobe M, Iwasaki S, Nii W, Goto N, Seki Y, Nakajima K, Nakamura K, Kariyazono H. Inhibitory Effect of Oleic Acid on Octanoylated Ghrelin Production. J Oleo Sci 2015; 64:1185-92. [DOI: 10.5650/jos.ess15137] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Shigeru Oiso
- Graduate School of Pharmaceutical Sciences, Nagasaki International University
- Department of Pharmacy, Faculty of Pharmaceutical Sciences, Nagasaki International University
| | - Miyuki Nobe
- Department of Pharmacy, Faculty of Pharmaceutical Sciences, Nagasaki International University
| | - Syuhei Iwasaki
- Department of Pharmacy, Faculty of Pharmaceutical Sciences, Nagasaki International University
| | - Wakana Nii
- Department of Pharmacy, Faculty of Pharmaceutical Sciences, Nagasaki International University
| | - Natsumi Goto
- Department of Pharmacy, Faculty of Pharmaceutical Sciences, Nagasaki International University
| | - Yukari Seki
- Department of Pharmacy, Faculty of Pharmaceutical Sciences, Nagasaki International University
| | - Kensuke Nakajima
- Graduate School of Pharmaceutical Sciences, Nagasaki International University
- Department of Pharmacy, Faculty of Pharmaceutical Sciences, Nagasaki International University
| | - Kazuo Nakamura
- Department of Biopharmaceutics, Nihon Pharmaceutical University
| | - Hiroko Kariyazono
- Graduate School of Pharmaceutical Sciences, Nagasaki International University
- Department of Pharmacy, Faculty of Pharmaceutical Sciences, Nagasaki International University
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Abstract
PURPOSE OF REVIEW To discuss recent research on the role of ghrelin in the regulation of carbohydrate and lipid metabolism in the context of its wider role in regulating energy balance. RECENT FINDINGS Ghrelin possesses a range of centrally and peripherally mediated metabolic actions influencing insulin glucose homeostasis and fatty acid metabolism and appetite. Although acyl ghrelin was previously thought to be the active hormone, recent evidence suggests that des-acyl ghrelin also possesses activity, and the enzyme ghrelin-O-acyl transferase regulates their interconversion. In partnership with insulin and leptin, ghrelin defends against energy deficit by enhancing hunger, conserving carbohydrate and promoting fat oxidation. In the postprandial state, it contributes to satiety, energy storage and favours glucose oxidation. New research suggests a range of new roles including addictive behaviours, cardiovascular protection, neuroprotection and regeneration and perhaps the ageing process. SUMMARY Ghrelin functions primarily as a short-term metabolic switch at the onset of fasting, gearing the fuel economy away from glucose uptake, conserving glucose for vital functions, favouring fatty acid oxidation and triggering food-seeking behaviour. The ghrelin system is a potential target for a range of pharmacological interventions, but its pleiotropic nature makes selective treatments challenging.
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Affiliation(s)
- Jonathan Pinkney
- Centre for Clinical Trials and Population Studies, Plymouth University Peninsula Schools of Medicine and Dentistry, Plymouth, United Kingdom
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Heppner KM, Piechowski CL, Müller A, Ottaway N, Sisley S, Smiley DL, Habegger KM, Pfluger PT, DiMarchi R, Biebermann H, Tschöp MH, Sandoval DA, Perez-Tilve D. Both acyl and des-acyl ghrelin regulate adiposity and glucose metabolism via central nervous system ghrelin receptors. Diabetes 2014; 63:122-31. [PMID: 24062249 PMCID: PMC3868046 DOI: 10.2337/db13-0414] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Growth hormone secretagogue receptors (GHSRs) in the central nervous system (CNS) mediate hyperphagia and adiposity induced by acyl ghrelin (AG). Evidence suggests that des-AG (dAG) has biological activity through GHSR-independent mechanisms. We combined in vitro and in vivo approaches to test possible GHSR-mediated biological activity of dAG. Both AG (100 nmol/L) and dAG (100 nmol/L) significantly increased inositol triphosphate formation in human embryonic kidney-293 cells transfected with human GHSR. As expected, intracerebroventricular infusion of AG in mice increased fat mass (FM), in comparison with the saline-infused controls. Intracerebroventricular dAG also increased FM at the highest dose tested (5 nmol/day). Chronic intracerebroventricular infusion of AG or dAG increased glucose-stimulated insulin secretion (GSIS). Subcutaneously infused AG regulated FM and GSIS in comparison with saline-infused control mice, whereas dAG failed to regulate these parameters even with doses that were efficacious when delivered intracerebroventricularly. Furthermore, intracerebroventricular dAG failed to regulate FM and induce hyperinsulinemia in GHSR-deficient (Ghsr(-/-)) mice. In addition, a hyperinsulinemic-euglycemic clamp suggests that intracerebroventricular dAG impairs glucose clearance without affecting endogenous glucose production. Together, these data demonstrate that dAG is an agonist of GHSR and regulates body adiposity and peripheral glucose metabolism through a CNS GHSR-dependent mechanism.
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Affiliation(s)
- Kristy M. Heppner
- Department of Medicine, Metabolic Diseases Institute, University of Cincinnati, Cincinnati, OH
| | - Carolin L. Piechowski
- Institute of Experimental Pediatric Endocrinology, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Anne Müller
- Institute of Experimental Pediatric Endocrinology, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Nickki Ottaway
- Department of Medicine, Metabolic Diseases Institute, University of Cincinnati, Cincinnati, OH
| | | | - David L. Smiley
- Department of Chemistry, Indiana University, Bloomington, IN
| | - Kirk M. Habegger
- Department of Medicine, Metabolic Diseases Institute, University of Cincinnati, Cincinnati, OH
| | - Paul T. Pfluger
- Department of Medicine, Metabolic Diseases Institute, University of Cincinnati, Cincinnati, OH
- Institute for Diabetes and Obesity, Hemholtz Zentrum München and Technische Universität München, Munich, Germany
| | | | - Heike Biebermann
- Institute of Experimental Pediatric Endocrinology, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Matthias H. Tschöp
- Department of Medicine, Metabolic Diseases Institute, University of Cincinnati, Cincinnati, OH
- Institute for Diabetes and Obesity, Hemholtz Zentrum München and Technische Universität München, Munich, Germany
| | - Darleen A. Sandoval
- Department of Medicine, Metabolic Diseases Institute, University of Cincinnati, Cincinnati, OH
| | - Diego Perez-Tilve
- Department of Medicine, Metabolic Diseases Institute, University of Cincinnati, Cincinnati, OH
- Corresponding author: Diego Perez-Tilve,
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Tong J, Dave N, Mugundu GM, Davis HW, Gaylinn BD, Thorner MO, Tschöp MH, D'Alessio D, Desai PB. The pharmacokinetics of acyl, des-acyl, and total ghrelin in healthy human subjects. Eur J Endocrinol 2013; 168:821-8. [PMID: 23482590 PMCID: PMC3740531 DOI: 10.1530/eje-13-0072] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND Ghrelin stimulates GH secretion and regulates energy and glucose metabolism. The two circulating isoforms, acyl (AG) and des-acyl (DAG) ghrelin, have distinct metabolic effects and are under active investigation for their therapeutic potentials. However, there is only limited data on the pharmacokinetics of AG and DAG. OBJECTIVES To evaluate key pharmacokinetic parameters of AG, DAG, and total ghrelin in healthy men and women. METHODS In study 1, AG (1, 3, and 5 μg/kg per h) was infused over 65 min in 12 healthy (8 F/4 M) subjects in randomized order. In study 2, AG (1 μg/kg per h), DAG (4 μg/kg per h), or both were infused over 210 min in ten healthy individuals (5 F/5 M). Plasma AG and DAG were measured using specific two-site ELISAs (study 1 and 2), and total ghrelin with a commercial RIA (study 1). Pharmacokinetic parameters were estimated by non-compartmental analysis. RESULTS After the 1, 3, and 5 μg/kg per h doses of AG, there was a dose-dependent increase in the maximum concentration (C(max)) and area under the curve (AUC(0-last)) of AG and total ghrelin. Among the different AG doses, there was no difference in the elimination half-life, systemic clearance (CL), and volume of distribution. DAG had decreased CL relative to AG. The plasma DAG:AG ratio was ~2:1 during steady-state infusion of AG. Infusion of AG caused an increase in DAG, but DAG administration did not change plasma AG. Ghrelin administration did not affect plasma acylase activity. CONCLUSIONS The pharmacokinetics of AG and total ghrelin appears to be linear and proportional in the dose range tested. AG and DAG have very distinct metabolic fates in the circulation. There is deacylation of AG in the plasma but no evidence of acylation.
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Affiliation(s)
- Jenny Tong
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Cincinnati, Cincinnati, Ohio 45219-0547, USA.
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A fluorescent peptide substrate facilitates investigation of ghrelin recognition and acylation by ghrelin O-acyltransferase. Anal Biochem 2013; 437:68-76. [DOI: 10.1016/j.ab.2013.02.013] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2012] [Revised: 02/12/2013] [Accepted: 02/16/2013] [Indexed: 01/24/2023]
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Rodríguez A, Becerril S, Valentí V, Moncada R, Méndez-Giménez L, Ramírez B, Lancha A, Martín M, Burrell MA, Catalán V, Gómez-Ambrosi J, Frühbeck G. Comment on “Short-Term Effects of Sleeve Gastrectomy and Caloric Restriction on Blood Pressure in Diet-Induced Obese Rats”. Obes Surg 2012. [DOI: 10.1007/s11695-012-0759-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Ma X, Lin Y, Lin L, Qin G, Pereira FA, Haymond MW, Butte NF, Sun Y. Ablation of ghrelin receptor in leptin-deficient ob/ob mice has paradoxical effects on glucose homeostasis when compared with ablation of ghrelin in ob/ob mice. Am J Physiol Endocrinol Metab 2012; 303:E422-31. [PMID: 22669248 PMCID: PMC3423126 DOI: 10.1152/ajpendo.00576.2011] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The orexigenic hormone ghrelin is important in diabetes because it has an inhibitory effect on insulin secretion. Ghrelin ablation in leptin-deficient ob/ob (Ghrelin(-/-):ob/ob) mice increases insulin secretion and improves hyperglycemia. The physiologically relevant ghrelin receptor is the growth hormone secretagogue receptor (GHS-R), and GHS-R antagonists are thought to be an effective strategy for treating diabetes. However, since some of ghrelin's effects are independent of GHS-R, we have utilized genetic approaches to determine whether ghrelin's effect on insulin secretion is mediated through GHS-R and whether GHS-R antagonism indeed inhibits insulin secretion. We investigated the effects of GHS-R on glucose homeostasis in Ghsr-ablated ob/ob mice (Ghsr(-/-):ob/ob). Ghsr ablation did not rescue the hyperphagia, obesity, or insulin resistance of ob/ob mice. Surprisingly, Ghsr ablation worsened the hyperglycemia, decreased insulin, and impaired glucose tolerance. Consistently, Ghsr ablation in ob/ob mice upregulated negative β-cell regulators (such as UCP-2, SREBP-1c, ChREBP, and MIF-1) and downregulated positive β-cell regulators (such as HIF-1α, FGF-21, and PDX-1) in whole pancreas; this suggests that Ghsr ablation impairs pancreatic β-cell function in leptin deficiency. Of note, Ghsr ablation in ob/ob mice did not affect the islet size; the average islet size of Ghsr(-/-):ob/ob mice is similar to that of ob/ob mice. In summary, because Ghsr ablation in leptin deficiency impairs insulin secretion and worsens hyperglycemia, this suggests that GHS-R antagonists may actually aggravate diabetes under certain conditions. The paradoxical effects of ghrelin ablation and Ghsr ablation in ob/ob mice highlight the complexity of the ghrelin-signaling pathway.
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Affiliation(s)
- Xiaojun Ma
- US Department of Agriculture/Agricultural Research Service Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA
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Chacko SK, Haymond MW, Sun Y, Marini JC, Sauer PJJ, Ma X, Sunehag AL. Effect of ghrelin on glucose regulation in mice. Am J Physiol Endocrinol Metab 2012; 302:E1055-62. [PMID: 22338071 DOI: 10.1152/ajpendo.00445.2011] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Improvement of glucose metabolism after bariatric surgery appears to be from the composite effect of the alterations in multiple circulating gut hormone concentrations. However, their individual effect on glucose metabolism during different conditions is not clear. The objective of this study was to determine whether ghrelin has an impact on glycogenolysis, gluconeogenesis, and insulin sensitivity (using a mice model). Rate of appearance of glucose, glycogenolysis, and gluconeogenesis were measured in wild-type (WT), ghrelin knockout (ghrelin(-/-)), and growth hormone secretagogue receptor knockout (Ghsr(-/-)) mice in the postabsorptive state. The physiological nature of the fasting condition was ascertained by a short-term fast commenced immediately at the end of the dark cycle. Concentrations of glucose and insulin were measured, and insulin resistance and hepatic insulin sensitivity were calculated. Glucose concentrations were not different among the groups during the food-deprived period. However, plasma insulin concentrations were lower in the ghrelin(-/-) and Ghsr(-/-) than WT mice. The rates of gluconeogenesis, glycogenolysis, and indexes of insulin sensitivity were higher in the ghrelin(-/-) and Ghsr(-/-) than WT mice during the postabsorptive state. Insulin receptor substrate 1 and glucose transporter 2 gene expressions in hepatic tissues of the ghrelin(-/-) and Ghsr(-/-) were higher compared with that in WT mice. This study demonstrates that gluconeogenesis and glycogenolysis are increased and insulin sensitivity is improved by the ablation of the ghrelin or growth hormone secretagogue receptor in mice.
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Affiliation(s)
- Shaji K Chacko
- Department of Pediatrics, Baylor College of Medicine Children’s Nutrition Research Center, United States Department of Agriculture/Agricultural Research Service, Houston, TX, USA
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Savic D, Bell GI, Nobrega MA. An in vivo cis-regulatory screen at the type 2 diabetes associated TCF7L2 locus identifies multiple tissue-specific enhancers. PLoS One 2012; 7:e36501. [PMID: 22590553 PMCID: PMC3349716 DOI: 10.1371/journal.pone.0036501] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2012] [Accepted: 04/02/2012] [Indexed: 12/21/2022] Open
Abstract
Genome-wide association studies (GWAS) have repeatedly shown an association between non-coding variants in the TCF7L2 locus and risk for type 2 diabetes (T2D), implicating a role for cis-regulatory variation within this locus in disease etiology. Supporting this hypothesis, we previously localized complex regulatory activity to the TCF7L2 T2D-associated interval using an in vivo bacterial artificial chromosome (BAC) enhancer-trapping reporter strategy. To follow-up on this broad initial survey of the TCF7L2 regulatory landscape, we performed a fine-mapping enhancer scan using in vivo mouse transgenic reporter assays. We functionally interrogated approximately 50% of the sequences within the T2D-associated interval, utilizing sequence conservation within this 92-kb interval to determine the regulatory potential of all evolutionary conserved sequences that exhibited conservation to the non-eutherian mammal opossum. Included in this study was a detailed functional interrogation of sequences spanning both protective and risk alleles of single nucleotide polymorphism (SNP) rs7903146, which has exhibited allele-specific enhancer function in pancreatic beta cells. Using these assays, we identified nine segments regulating various aspects of the TCF7L2 expression profile and that constitute nearly 70% of the sequences tested. These results highlight the regulatory complexity of this interval and support the notion that a TCF7L2 cis-regulatory disruption leads to T2D predisposition.
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Affiliation(s)
- Daniel Savic
- Department of Human Genetics, University of Chicago, Chicago, Illinois, United States of America.
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Vignjević S, Todorović V, Damjanović S, Budeč M, Mitrović O, Djikić D, Drndarević N, Mićić M, Mišković-Krivokapić J, Djuričić S, Nikolić I. Similar developmental patterns of ghrelin- and glucagon-expressing cells in the human pancreas. Cells Tissues Organs 2012; 196:362-73. [PMID: 22538872 DOI: 10.1159/000335469] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/27/2011] [Indexed: 12/15/2022] Open
Abstract
The pancreas appears to be a major source of ghrelin during fetal development, but the ontogeny of ghrelin cells in the human pancreas and their developmental relationship with α- and β-cells remain largely unknown. In the present study, we examined the dynamics of ghrelin cell growth, colocalization of ghrelin with major pancreatic hormones and defined the similarities and differences among developmental patterns of ghrelin-, glucagon- and insulin-expressing cells in the human pancreas. To this end, paraffin-embedded pancreatic tissue sections from human embryos and fetuses were assessed by immunohistochemistry. Ghrelin-positive cells were first detected in the pancreas of 11-week-old fetuses. With advancing gestational age, both ghrelin- and glucagon-expressing cells were increasingly observed at the periphery of the developing islets, whereas insulin-containing cells were typically found in the islet core. Double immunohistochemistry showed that ghrelin-expressing cells were clearly separate from insulin-, somatostatin- and pancreatic polypeptide-containing cells. In contrast, cells coexpressing ghrelin and glucagon were sporadically detected during both the early and late fetal periods. Furthermore, morphometric analysis revealed a similar trend in the volume density of ghrelin- and glucagon-positive cells, and a contrasting pattern in β-cell density at specific time points during the development of the human pancreas. This study demonstrates that the developmental pattern of ghrelin cells, although clearly distinct, is quite similar to that of glucagon-expressing cells. The obtained findings indicate a close lineage relationship between these cell populations, a functional relationship between their secretory products and an auto/paracrine mode of ghrelin-glucagon interaction in pancreatic development.
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Affiliation(s)
- Sanja Vignjević
- Institute for Medical Research, University of Belgrade, Belgrade, Serbia.
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Granata R, Settanni F, Julien M, Nano R, Togliatto G, Trombetta A, Gallo D, Piemonti L, Brizzi MF, Abribat T, van Der Lely AJ, Ghigo E. Des-acyl ghrelin fragments and analogues promote survival of pancreatic β-cells and human pancreatic islets and prevent diabetes in streptozotocin-treated rats. J Med Chem 2012; 55:2585-96. [PMID: 22352743 DOI: 10.1021/jm201223m] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Des-acyl ghrelin, although devoid of binding to ghrelin receptor (GRLN), exerts many biological effects, including regulation of glucose and lipid metabolism. Indeed, des-acyl ghrelin promotes pancreatic β-cell and human islet cell survival and prevents diabetes in streptozotocin (STZ) treated rats. We investigated whether des-acyl ghrelin fragments excluding serine(3), which is essential for binding to GRLN, would display similar actions. Among the different compounds tested, des-acyl ghrelin((6-13)) and des-acyl ghrelin((6-13)) with alanine substitutions or cyclization, but not with d-amino acid substitutions, showed the best survival effect, similar to des-acyl ghrelin. Des-acyl ghrelin((6-13)) even prevented diabetes in STZ-treated rats and protected human circulating angiogenic cells from oxidative stress and senescence, similar to des-acyl ghrelin. These results suggest that not only full-length des-acyl ghrelin but also short des-acyl ghrelin fragments have clear beneficial effects on several tissues in vitro and in vivo.
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Affiliation(s)
- Riccarda Granata
- Laboratory of Molecular and Cellular Endocrinology, University of Turin, Corso Dogliotti 14, 10126 Turin, Italy.
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Xu GY, Li Y, Zhang WZ. Gastric mammalian target of rapamycin signaling, hormone production and energy metabolism. World J Gastrointest Pathophysiol 2011; 2:109-13. [PMID: 22180845 PMCID: PMC3240903 DOI: 10.4291/wjgp.v2.i6.109] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2011] [Revised: 10/07/2011] [Accepted: 10/14/2011] [Indexed: 02/06/2023] Open
Abstract
The obesity epidemic imposes a significant health burden on human beings. Current understanding of the mechanisms underlying the development of obesity is incomplete and contemporary treatment is often ineffective. Gastrointestinal hormones are important regulators of food intake and energy metabolism. Previous studies indicate that the mammalian target of rapamycin signaling pathway in the gastric mucosa is crucially involved in fuel sensing in the gastrointestinal tract and plays a critical role in the coordination of nutrient availability and ingestive behavior via the production of gastric hormones. As an important component of the brain-gut axis regulating food intake and energy homeostasis, energy sensing in the gastrointestinal tract may provide a novel insight into our understanding of the precise coordination between the organism and cellular energy state.
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Eubanks LM, Stowe GN, De Lamo Marin S, Mayorov AV, Hixon MS, Janda KD. Identification of α2 Macroglobulin as a Major Serum Ghrelin Esterase. Angew Chem Int Ed Engl 2011. [DOI: 10.1002/ange.201104512] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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32
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Eubanks LM, Stowe GN, De Lamo Marin S, Mayorov AV, Hixon MS, Janda KD. Identification of α2 macroglobulin as a major serum ghrelin esterase. Angew Chem Int Ed Engl 2011; 50:10699-702. [PMID: 21928452 DOI: 10.1002/anie.201104512] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2011] [Indexed: 11/10/2022]
Affiliation(s)
- Lisa M Eubanks
- Department of Chemistry, The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
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