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Keifi Bajestani A, Alavi MS, Etemad L, Roohbakhsh A. Role of orphan G-protein coupled receptors in tissue ischemia: A comprehensive review. Eur J Pharmacol 2024; 978:176762. [PMID: 38906238 DOI: 10.1016/j.ejphar.2024.176762] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2024] [Revised: 06/12/2024] [Accepted: 06/19/2024] [Indexed: 06/23/2024]
Abstract
Ischemic events lead to many diseases and deaths worldwide. Ischemia/reperfusion (I/R) occurs due to reduced blood circulation in tissues followed by blood reflow. Reoxygenation of ischemic tissues is characterized by oxidative stress, inflammation, energy distress, and endoplasmic reticulum stress. There are still no adequate clinical protocols or pharmacological approaches to address the consequences of I/R damage. G protein-coupled receptors (GPCRs) are important therapeutic targets. They compose a large family of seven transmembrane-spanning proteins that are involved in many biological functions. Orphan GPCRs are a large subgroup of these receptors expressed in different organs. In the present review, we summarized the literature regarding the role of orphan GPCRs in I/R in different organs. We focused on the effect of these receptors on modulating cellular and molecular processes underlying ischemia including apoptosis, inflammation, and autophagy. The study showed that GPR3, GPR4, GPR17, GPR30, GPR31, GPR35, GPR37, GPR39, GPR55, GPR65, GPR68, GPR75, GPR81, and GPR91 are involved in ischemic events, mainly in the brain and heart. These receptors offer new possibilities for treating I/R injuries in the body.
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Affiliation(s)
- Alireza Keifi Bajestani
- Department of Pharmacodynamics and Toxicology, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Mohaddeseh Sadat Alavi
- Department of Pharmacology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Leila Etemad
- Pharmaceutical Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Ali Roohbakhsh
- Department of Pharmacodynamics and Toxicology, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran; Pharmaceutical Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran.
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Doboszewska U, Maret W, Wlaź P. GPR39: An orphan receptor begging for ligands. Drug Discov Today 2024; 29:103861. [PMID: 38122967 DOI: 10.1016/j.drudis.2023.103861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Revised: 12/03/2023] [Accepted: 12/14/2023] [Indexed: 12/23/2023]
Abstract
Progress in the understanding of the receptor GPR39 is held up by inconsistent pharmacological data. First, the endogenous ligand(s) remain(s) contentious. Data pointing to zinc ions (Zn2+) and/or eicosanoids as endogenous ligands are a matter of debate. Second, there are uncertainties in the specificity of the widely used synthetic ligand (agonist) TC-G 1008. Third, activation of GPR39 has been often proposed as a novel treatment strategy, but new data also support that inhibition might be beneficial in certain disease contexts. Constitutive activity/promiscuous signaling suggests the need for antagonists/inverse agonists in addition to (biased) agonists. Here, we scrutinize data on the signaling and functions of GPR39 and critically assess factors that might have contributed to divergent outcomes and interpretations of investigations on this important receptor.
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Affiliation(s)
- Urszula Doboszewska
- Department of Pharmacobiology, Jagiellonian University Medical College, Medyczna 9, PL 30-688 Kraków, Poland
| | - Wolfgang Maret
- Department of Nutritional Sciences, School of Life Course and Population Sciences, Faculty of Life Sciences and Medicine, King's College London, London SE1 9NH, UK
| | - Piotr Wlaź
- Department of Animal Physiology and Pharmacology, Institute of Biological Sciences, Maria Curie-Skłodowska University, Akademicka 19, PL 20-033 Lublin, Poland.
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Villarreal D, Pradhan G, Zhou Y, Xue B, Sun Y. Diverse and Complementary Effects of Ghrelin and Obestatin. Biomolecules 2022; 12:biom12040517. [PMID: 35454106 PMCID: PMC9028691 DOI: 10.3390/biom12040517] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2022] [Revised: 03/21/2022] [Accepted: 03/25/2022] [Indexed: 02/06/2023] Open
Abstract
Ghrelin and obestatin are two “sibling proteins” encoded by the same preproghrelin gene but possess an array of diverse and complex functions. While there are ample literature documenting ghrelin’s functions, the roles of obestatin are less clear and controversial. Ghrelin and obestatin have been perceived to be antagonistic initially; however, recent studies challenge this dogma. While they have opposing effects in some systems, they function synergistically in other systems, with many functions remaining debatable. In this review, we discuss their functional relationship under three “C” categories, namely complex, complementary, and contradictory. Their functions in food intake, weight regulation, hydration, gastrointestinal motility, inflammation, and insulin secretion are complex. Their functions in pancreatic beta cells, cardiovascular, muscle, neuroprotection, cancer, and digestive system are complementary. Their functions in white adipose tissue, thermogenesis, and sleep regulation are contradictory. Overall, this review accumulates the multifaceted functions of ghrelin and obestatin under both physiological and pathological conditions, with the intent of contributing to a better understanding of these two important gut hormones.
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Affiliation(s)
- Daniel Villarreal
- Department of Nutrition, Texas A & M University, College Station, TX 77843, USA;
| | - Geetali Pradhan
- USDA/ARS Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA;
- Interdepartmental Program in Translational Biology and Molecular Medicine, Baylor College of Medicine, Houston, TX 77030, USA
| | - Yu Zhou
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Qingdao University, Qingdao 266071, China;
| | - Bingzhong Xue
- Department of Biology, Georgia State University, Atlanta, GA 30303, USA;
| | - Yuxiang Sun
- Department of Nutrition, Texas A & M University, College Station, TX 77843, USA;
- USDA/ARS Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX 77030, USA;
- Correspondence: ; Tel.: +1-979-862-9143
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Laitakari A, Liu L, Frimurer TM, Holst B. The Zinc-Sensing Receptor GPR39 in Physiology and as a Pharmacological Target. Int J Mol Sci 2021; 22:ijms22083872. [PMID: 33918078 PMCID: PMC8070507 DOI: 10.3390/ijms22083872] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 03/31/2021] [Accepted: 04/06/2021] [Indexed: 12/16/2022] Open
Abstract
The G-protein coupled receptor GPR39 is abundantly expressed in various tissues and can be activated by changes in extracellular Zn2+ in physiological concentrations. Previously, genetically modified rodent models have been able to shed some light on the physiological functions of GPR39, and more recently the utilization of novel synthetic agonists has led to the unraveling of several new functions in the variety of tissues GPR39 is expressed. Indeed, GPR39 seems to be involved in many important metabolic and endocrine functions, but also to play a part in inflammation, cardiovascular diseases, saliva secretion, bone formation, male fertility, addictive and depression disorders and cancer. These new discoveries offer opportunities for the development of novel therapeutic approaches against many diseases where efficient therapeutics are still lacking. This review focuses on Zn2+ as an endogenous ligand as well as on the novel synthetic agonists of GPR39, placing special emphasis on the recently discovered physiological functions and discusses their pharmacological potential.
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Affiliation(s)
- Anna Laitakari
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark; (A.L.); (L.L.); (T.M.F.)
| | - Lingzhi Liu
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark; (A.L.); (L.L.); (T.M.F.)
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
| | - Thomas M. Frimurer
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark; (A.L.); (L.L.); (T.M.F.)
| | - Birgitte Holst
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark; (A.L.); (L.L.); (T.M.F.)
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen, Denmark
- Correspondence:
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Green BD, Grieve DJ. Biochemical properties and biological actions of obestatin and its relevence in type 2 diabetes. Peptides 2018; 100:249-259. [PMID: 29412827 DOI: 10.1016/j.peptides.2017.12.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Revised: 12/05/2017] [Accepted: 12/06/2017] [Indexed: 12/15/2022]
Abstract
Obestatin was initially discovered in rat stomach extract, and although it is principally produced in the gastric mucosa, it can be found throughout the gastrointestinal tract. This 23-amino acid C-terminally amidated peptide is derived from preproghrelin and has been ascribed a wide range of metabolic effects relevant to type 2 diabetes. Obestatin reportedly inhibits gastrointestinal motility, reduces food intake and lowers body weight and improves lipid metabolism. Furthermore, it appears to exert actions on the pancreatic β-cell, most notably increasing β-cell mass and upregulating genes associated with insulin production and β-cell regeneration, with relevance to type 2 diabetes. It is becoming evident that obestatin also exerts pleiotropic effects on the cardiovascular system, possibly modulating blood pressure, endothelial function and triggering cardioprotective mechanisms, which may be important in determining cardiovascular outcomes in type 2 diabetes. Furthermore, it seems that like other gut peptides obestatin has neuroprotective properties. This review examines the biochemical properties of the obestatin peptide (its structure, sequence, stability and distribution) and the candidate receptors through which it may act. It provides a balanced examination of the reported pancreatic and extrapancreatic actions of obestatin and evaluates its potential relevance with respect to diabetes therapy, together with discussion of direct evidence linking alterations in obestatin signalling with obesity/diabetes and other diseases.
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Affiliation(s)
- Brian D Green
- Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast, Belfast, BT9 5BN, UK.
| | - David J Grieve
- Centre for Experimental Medicine, Queen's University Belfast, Belfast, BT9 7AE, UK
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Kilic N, Dagli N, Aydin S, Erman F, Bek Y, Akin O, Kilic SS, Erdemli HK, Alacam H. Saliva/serum ghrelin, obestatin and homocysteine levels in patients with ischaemic heart disease. Cardiovasc J Afr 2017; 28:159-164. [PMID: 28759087 PMCID: PMC5558140 DOI: 10.5830/cvja-2016-075] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2015] [Accepted: 07/17/2016] [Indexed: 11/06/2022] Open
Abstract
BACKGROUND We aimed to compare ghrelin, obestatin, homocysteine (Hcy), vitamin B12 and folate levels in the serum and saliva of ischaemic heart disease patients. METHODS Serum and saliva were collected from 33 ischaemic heart disease (IHD) patients and 28 age- and body mass index-matched healthy individuals. Levels of acylated and desacylated ghrelin, obestatin and Hcy were determined using the ELISA method. RESULTS Acylated ghrelin, desacylated ghrelin and obestatin levels in the saliva were found to be higher than those in the serum of the control group, while acylated and desacylated ghrelin levels in the saliva were significantly lower than those in the serum. Obestatin levels were higher in IHD patients (p = 0.001). Saliva and serum vitamin B12 and folate levels in IHD patients were significantly lower than in the control group (p = 0.001). CONCLUSIONS It was determined that serum ghrelin levels increased in ischaemic heart disease patients, while serum levels of obestatin decreased.
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Affiliation(s)
- Nermin Kilic
- Department of Medical Biochemistry, School of Medicine, Ondokuz Mayis University, Samsun, Turkey
| | - Necati Dagli
- Department of Cardiology, School of Medicine, Firat University, Elazig, Turkey
| | - Suleyman Aydin
- Department of Medical Biochemistry, School of Medicine, Firat University, Elazig, Turkey
| | - Fazilet Erman
- Department of Medical Biochemistry, School of Medicine, Firat University, Elazig, Turkey
| | - Yuksel Bek
- Department of Biostatistics, School of Medicine, Ondokuz Mayis University, Samsun, Turkey
| | - Okhan Akin
- Biochemistry Laboratory, Kecioren Education and Research Hospital, Ankara, Turkey
| | - S S Kilic
- Department of Infectious Diseases and Microbiology, Training and Research Hospital, Samsun, Turkey
| | - Haci Kemal Erdemli
- Department of Medical Biochemistry, Corum Training and Research Hospital, Corum, Turkey
| | - Hasan Alacam
- Department of Medical Biochemistry, School of Medicine, Hacettepe University, Ankara, Turkey.
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7
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Cowan E, Burch KJ, Green BD, Grieve DJ. Obestatin as a key regulator of metabolism and cardiovascular function with emerging therapeutic potential for diabetes. Br J Pharmacol 2016; 173:2165-81. [PMID: 27111465 DOI: 10.1111/bph.13502] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Revised: 04/05/2016] [Accepted: 04/15/2016] [Indexed: 01/01/2023] Open
Abstract
Obestatin is a 23-amino acid C-terminally amidated gastrointestinal peptide derived from preproghrelin and which forms an α helix. Although obestatin has a short biological half-life and is rapidly degraded, it is proposed to exert wide-ranging pathophysiological actions. Whilst the precise nature of many of its effects is unclear, accumulating evidence supports positive actions on both metabolism and cardiovascular function. For example, obestatin has been reported to inhibit food and water intake, body weight gain and gastrointestinal motility and also to mediate promotion of cell survival and prevention of apoptosis. Obestatin-induced increases in beta cell mass, enhanced adipogenesis and improved lipid metabolism have been noted along with up-regulation of genes associated with beta cell regeneration, insulin production and adipogenesis. Furthermore, human circulating obestatin levels generally demonstrate an inverse association with obesity and diabetes, whilst the peptide has been shown to confer protective metabolic effects in experimental diabetes, suggesting that it may hold therapeutic potential in this setting. Obestatin also appears to be involved in blood pressure regulation and to exert beneficial effects on endothelial function, with experimental studies indicating that it may also promote cardioprotective actions against, for example, ischaemia-reperfusion injury. This review will present a critical appraisal of the expanding obestatin research area and discuss the emerging therapeutic potential of this peptide for both metabolic and cardiovascular complications of diabetes.
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Affiliation(s)
- Elaine Cowan
- Queen's University Belfast, Institute for Global Food Security, School of Biological Sciences, Belfast, UK
| | - Kerry J Burch
- Queen's University Belfast, Wellcome-Wolfson Institute for Experimental Medicine, Belfast, UK
| | - Brian D Green
- Queen's University Belfast, Institute for Global Food Security, School of Biological Sciences, Belfast, UK
| | - David J Grieve
- Queen's University Belfast, Wellcome-Wolfson Institute for Experimental Medicine, Belfast, UK
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8
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Maternal serum ratio of ghrelin to obestatin decreased in preeclampsia. Pregnancy Hypertens 2015; 5:263-6. [DOI: 10.1016/j.preghy.2015.09.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Revised: 05/18/2015] [Accepted: 09/07/2015] [Indexed: 11/24/2022]
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Su XJ, Dong RX, Li YP, Yang SG, Li ZF. Obestatin and cardiovascular health. Peptides 2014; 52:58-60. [PMID: 24333655 DOI: 10.1016/j.peptides.2013.11.023] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Revised: 11/23/2013] [Accepted: 11/25/2013] [Indexed: 10/25/2022]
Abstract
Obestatin, encoded by the same gene as ghrelin, was first described as a physiological opponent of ghrelin through an interaction with the orphan receptor GPR39. However, the effects of obestatin were not totally contrary to the effects of ghrelin in cardiovascular regulations based on the recent studies. We summarize here the current evidences surrounding the cardiovascular actions of obestatin, and the possible implications of obestatin as a therapeutic agent in common conditions such as hypertension and heart failure.
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Affiliation(s)
- Xue-Jia Su
- Department of Thoracic Surgery, No. 88 Hospital of PLA, Tai'an City, Shandong Province 271000, China
| | - Rui-Xin Dong
- Department of Cardiology, No. 88 Hospital of PLA, Tai'an City, Shandong Province 271000, China
| | - Yan-Peng Li
- Department of Out-patient, No. 88 Hospital of PLA, Tai'an City, Shandong Province 271000, China
| | - Shu-Guang Yang
- Department of Cardiology, No. 88 Hospital of PLA, Tai'an City, Shandong Province 271000, China.
| | - Zhao-Feng Li
- Department of Cardiology, No. 88 Hospital of PLA, Tai'an City, Shandong Province 271000, China.
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Protection of MES23.5 dopaminergic cells by obestatin is mediated by proliferative rather than anti-apoptotic action. Neurosci Bull 2014; 30:118-24. [PMID: 24478041 DOI: 10.1007/s12264-013-1405-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2013] [Accepted: 09/24/2013] [Indexed: 12/14/2022] Open
Abstract
Obestatin is an endogenous peptide sharing a precursor with ghrelin. This study aims to investigate whether and how obestatin protects MES23.5 dopaminergic cells against 1-methyl-4-phenylpyridinium (MPP(+))-induced neurotoxicity. MES23.5 cells were pretreated with obestatin (10(-13)-10(-6) mol/L) for 20 min prior to incubation with 200 μmol/L MPP(+) for 12 or 24 h, or treated with obestatin alone (10(-13) to 10(-6) mol/L) for 0, 6, 12, and 24 h. The methyl thiazolyl tetrazolium (MTT) assay was used to measure cell viability. Flow cytometry was used to measure the caspase-3 activity and the mitochondrial transmembrane potential. Proliferating cell nuclear antigen (PCNA) protein levels were determined by Western blotting. Obestatin (10(-13) to 10(-7) mol/L) pretreatment blocked or even reversed the MPP(+)-induced reduction of viability in MES23.5 cells, but had no effect on MPP(+)-induced mitochondrial transmembrane potential collapse and caspase-3 activation. When applied alone, obestatin increased viability. Elevated PCNA levels occurred with 10(-7), 10(-9), 10(-11) and 10(-13) mol/L obestatin treatment for 12 h. The results suggest that the protective effects of obestatin against MPP(+) in MES23.5 cells are due to its proliferation-promoting rather than anti-apoptotic effects.
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11
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Gesmundo I, Gallo D, Favaro E, Ghigo E, Granata R. Obestatin: a new metabolic player in the pancreas and white adipose tissue. IUBMB Life 2013; 65:976-82. [PMID: 24217898 DOI: 10.1002/iub.1226] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Revised: 10/10/2013] [Accepted: 10/11/2013] [Indexed: 01/14/2023]
Abstract
Obestatin is a 23 amino acid amidated peptide, member of the preproghrelin gene-derived peptides. Initially, obestatin was reported to exert opposite effects to those of ghrelin on food intake and body weight gain, through interaction with GPR39; however, these findings are still strongly debated and obestatin biological role remains largely unknown. Interestingly, binding of obestatin to the glucagon-like peptide 1 receptor has been recently suggested. Despite being a controversial peptide, recent findings have clearly indicated that obestatin is indeed a multifunctional peptide, exerting a variety of effects, such as stimulation of cell proliferation, survival and differentiation, influence on glucose and lipid metabolism, as well as anti-inflammatory and cardioprotective actions. Its positive effects on glucose and lipid metabolism candidate this peptide as a potential therapeutic tool in pathological conditions such as insulin resistance and diabetes.
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Affiliation(s)
- Iacopo Gesmundo
- Division of Endocrinology, Diabetology and Metabolism, Department of Medical Sciences, University of Torino, Torino, Italy
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12
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Atalayer D, Gibson C, Konopacka A, Geliebter A. Ghrelin and eating disorders. Prog Neuropsychopharmacol Biol Psychiatry 2013; 40:70-82. [PMID: 22960103 PMCID: PMC3522761 DOI: 10.1016/j.pnpbp.2012.08.011] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/06/2012] [Revised: 08/03/2012] [Accepted: 08/19/2012] [Indexed: 12/25/2022]
Abstract
There is growing evidence supporting a multifactorial etiology that includes genetic, neurochemical, and physiological components for eating disorders above and beyond the more conventional theories based on psychological and sociocultural factors. Ghrelin is one of the key gut signals associated with appetite, and the only known circulating hormone that triggers a positive energy balance by stimulating food intake. This review summarizes recent findings and several conflicting reports on ghrelin in eating disorders. Understanding these findings and inconsistencies may help in developing new methods to prevent and treat patients with these disorders.
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Affiliation(s)
- Deniz Atalayer
- Department of Medicine, New York Obesity Research and Nutrition Center, St. Luke's-Roosevelt Hospital, New York, NY, USA.
| | - Charlisa Gibson
- Department of Medicine, New York Obesity Research and Nutrition Center, St. Luke’s-Roosevelt Hospital, New York NY, USA
| | - Alexandra Konopacka
- Department of Medicine, New York Obesity Research and Nutrition Center, St. Luke’s-Roosevelt Hospital, New York NY, USA
| | - Allan Geliebter
- Department of Medicine, New York Obesity Research and Nutrition Center, St. Luke’s-Roosevelt Hospital, New York NY, USA,Department of Psychiatry, Columbia University College of Physicians and Surgeons, New York, NY, USA,Department of Psychology, Touro College, New York, NY, USA
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Slavin TP, Feng T, Schnell A, Zhu X, Elston RC. Two-marker association tests yield new disease associations for coronary artery disease and hypertension. Hum Genet 2011; 130:725-33. [PMID: 21626137 PMCID: PMC3576836 DOI: 10.1007/s00439-011-1009-6] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2010] [Accepted: 05/17/2011] [Indexed: 12/16/2022]
Abstract
It has been postulated that multiple-marker methods may have added ability, over single-marker methods, to detect genetic variants associated with disease. The Wellcome Trust Case Control Consortium (WTCCC) provided the first successful large genome-wide association studies (GWAS) which included single-marker association analyses for seven common complex diseases. Of those signals detected, only one was associated with coronary artery disease (CAD), and none were identified for hypertension (HTN). Our objective was to find additional genetic associations and pathways for cardiovascular disease by examining the WTCCC data for variants associated with CAD and HTN using two-marker testing methods. We applied two-marker association testing to the WTCCC dataset, which includes ~2,000 affected individuals with each disorder, and a shared pool of ~3,000 controls, all genotyped using Affymetrix GeneChip 500 K arrays. For CAD, we detected single nucleotide polymorphisms (SNP) pairs in three genes showing genome-wide significance: HFE2, STK32B, and DIPC2. The most notable SNP pairs in a non-protein-coding region were at 9p21, a known major CAD-associated region. For HTN, we detected SNP pairs in five genes: GPR39, XRCC4, MYO6, ZFAT, and MACROD2. Four further associated SNP pair regions were at least 70 kb from any known gene. We have shown that novel, multiple-marker, statistical methods can be of use in finding variants in GWAS. We describe many new, associated variants for both CAD and HTN and describe their known genetic mechanisms.
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Affiliation(s)
- Thomas P Slavin
- Department of Genetics, Center for Human Genetics, University Hospitals of Cleveland and Case Western Reserve University, 10524 Euclid Avenue, Cleveland, OH, USA.
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Pacheco-Pantoja EL, Ranganath LR, Gallagher JA, Wilson PJM, Fraser WD. Receptors and effects of gut hormones in three osteoblastic cell lines. BMC PHYSIOLOGY 2011; 11:12. [PMID: 21801348 PMCID: PMC3162581 DOI: 10.1186/1472-6793-11-12] [Citation(s) in RCA: 111] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/28/2011] [Accepted: 07/29/2011] [Indexed: 12/23/2022]
Abstract
Background In recent years the interest on the relationship of gut hormones to bone processes has increased and represents one of the most interesting aspects in skeletal research. The proportion of bone mass to soft tissue is a relationship that seems to be controlled by delicate and subtle regulations that imply "cross-talks" between the nutrient intake and tissues like fat. Thus, recognition of the mechanisms that integrate a gastrointestinal-fat-bone axis and its application to several aspects of human health is vital for improving treatments related to bone diseases. This work analysed the effects of gut hormones in cell cultures of three osteoblastic cell lines which represent different stages in osteoblastic development. Also, this is the first time that there is a report on the direct effects of glucagon-like peptide 2, and obestatin on osteoblast-like cells. Methods mRNA expression levels of five gut hormone receptors (glucose-dependent insulinotropic peptide [GIP], glucagon-like peptide 1 [GLP-1], glucagon-like peptide 2 [GLP-2], ghrelin [GHR] and obestatin [OB]) were analysed in three osteoblastic cell lines (Saos-2, TE-85 and MG-63) showing different stages of osteoblast development using reverse transcription and real time polymerase chain reaction. The responses to the gut peptides were studied using assays for cell viability, and biochemical bone markers: alkaline phosphatase (ALP), procollagen type 1 amino-terminal propeptides (P1NP), and osteocalcin production. Results The gut hormone receptor mRNA displayed the highest levels for GIP in Saos-2 and the lowest levels in MG-63, whereas GHR and GPR39 (the putative obestatin receptor) expression was higher in TE-85 and MG-63 and lower in Saos-2. GLP-1 and GLP-2 were expressed only in MG-63 and TE-85. Treatment of gut hormones to cell lines showed differential responses: higher levels in cell viability in Saos-2 after GIP, in TE-85 and MG-63 after GLP-1, GLP-2, ghrelin and obestatin. ALP showed higher levels in Saos-2 after GIP, GHR and OB and in TE-85 after GHR. P1NP showed higher levels after GIP and OB in Saos-2. Decreased levels of P1NP were observed in TE-85 and MG-63 after GLP-1, GLP-2 and OB. MG-63 showed opposite responses in osteocalcin levels after GLP-2. Conclusions These results suggest that osteoblast activity modulation varies according to different development stage under different nutrition related-peptides.
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Affiliation(s)
- Elda L Pacheco-Pantoja
- Escuela de Medicina, Universidad Anáhuac Mayab, Km 15,5 Carr Merida-Progreso, 97310, Mérida, Yucatán, México.
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Seim I, Walpole C, Amorim L, Josh P, Herington A, Chopin L. The expanding roles of the ghrelin-gene derived peptide obestatin in health and disease. Mol Cell Endocrinol 2011; 340:111-7. [PMID: 21459124 DOI: 10.1016/j.mce.2011.03.018] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2011] [Revised: 03/23/2011] [Accepted: 03/25/2011] [Indexed: 01/18/2023]
Abstract
Obestatin is a 23 amino acid, ghrelin gene-derived peptide hormone produced in the stomach and a range of other tissues throughout the body. While it was initially reported that obestatin opposed the actions of ghrelin with regards to appetite and food intake, it is now clear that obestatin is not an endogenous ghrelin antagonist, but it is a multi-functional peptide hormone in its own right. In this review we will discuss the controversies associated with the discovery of obestatin and explore emerging central and peripheral roles of obestatin, which includes adipogenesis, pancreatic homeostasis and cancer.
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Affiliation(s)
- Inge Seim
- Queensland University of Technology, Queensland, Brisbane, Australia
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16
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Li JB, Asakawa A, Cheng K, Li Y, Chaolu H, Tsai M, Inui A. Biological effects of obestatin. Endocrine 2011; 39:205-11. [PMID: 21424587 DOI: 10.1007/s12020-011-9453-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2011] [Accepted: 02/05/2011] [Indexed: 10/18/2022]
Abstract
Obestatin, a 23-amino-acid peptide, is derived from the preproghrelin precursor. Obestatin was identified in 2005 as a hormone regulating food intake and energy, and having opposite effects to those of ghrelin. However, as studies have progressed, many disputes on the physiological function of obestatin have emerged. The food intake suppressive effects of obestatin have not been replicated in many studies. Nonetheless, many biological roles of obestatin have been revealed, and obestatin is thought to be associated with a variety of biological functions such as feeding, drinking, incretion, memory, and sleep, and with neuropsychiatric manifestations. The biological effects of obestatin will be reviewed in this article.
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Affiliation(s)
- Jiang-Bo Li
- Department of Social and Behavioral Medicine, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima, 890-8520, Japan
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17
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Lacquaniti A, Donato V, Chirico V, Buemi A, Buemi M. Obestatin: An Interesting but Controversial Gut Hormone. ANNALS OF NUTRITION AND METABOLISM 2011; 59:193-9. [DOI: 10.1159/000334106] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2011] [Accepted: 09/30/2011] [Indexed: 12/14/2022]
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18
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Popovics P, Stewart AJ. GPR39: a Zn(2+)-activated G protein-coupled receptor that regulates pancreatic, gastrointestinal and neuronal functions. Cell Mol Life Sci 2011; 68:85-95. [PMID: 20812023 PMCID: PMC11114682 DOI: 10.1007/s00018-010-0517-1] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2010] [Revised: 08/16/2010] [Accepted: 08/17/2010] [Indexed: 10/19/2022]
Abstract
GPR39 is a vertebrate G protein-coupled receptor related to the ghrelin/neurotensin receptor subfamily. The receptor is expressed in a range of tissues including the pancreas, gut/gastrointestinal tract, liver, kidney and in some regions of the brain. GPR39 was initially thought to be the cognitive receptor for the peptide hormone, obestatin. However, subsequent in vitro studies have failed to demonstrate binding of this peptide to the receptor. Zn(2+) has been shown to be a potent stimulator of GPR39 activity via the Gα(q), Gα(12/13) and Gα(s) pathways. The potency and specificity of Zn(2+) in activating GPR39 suggest it to be a physiologically important agonist. GPR39 is now emerging as an important transducer of autocrine and paracrine Zn(2+) signals, impacting upon cellular processes such as insulin secretion, gastric emptying, neurotransmission and epithelial repair. This review focuses on the molecular, structural and biological properties of GPR39 and its various physiological functions.
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Affiliation(s)
- Petra Popovics
- School of Medicine, University of St Andrews, Medical and Biological Sciences Building, St Andrews, Fife KY16 9TF UK
| | - Alan J. Stewart
- School of Medicine, University of St Andrews, Medical and Biological Sciences Building, St Andrews, Fife KY16 9TF UK
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19
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Abstract
The discovery of ghrelin has elucidated the role of the stomach as an important organ in the regulation of growth hormone release and energy homeostasis. Ghrelin is orexigenic; it is secreted from the stomach and circulates in the blood stream under fasting conditions, indicating that it transmits a hunger signal from the periphery to the central nervous system. Ghrelin is a peptide hormone, in which serine 3 (threonine 3 in frogs) is modified by an n-octanoic acid; this modification is essential for ghrelin's activity. Recently the enzymes responsible for the processing from the ghrelin precursor to active n-octanoyl-modified ghrelin have been identified. This review surveys the processing pathway from ghrelin gene to mature ghrelin peptide and summarizes our knowledge of the regulatory mechanism of ghrelin secretion and function.
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20
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Veldhuis JD, Bowers CY. Integrating GHS into the Ghrelin System. INTERNATIONAL JOURNAL OF PEPTIDES 2010; 2010:879503. [PMID: 20798846 PMCID: PMC2925380 DOI: 10.1155/2010/879503] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/24/2009] [Accepted: 12/30/2009] [Indexed: 12/21/2022]
Abstract
Oligopeptide derivatives of metenkephalin were found to stimulate growth-hormone (GH) release directly by pituitary somatotrope cells in vitro in 1977. Members of this class of peptides and nonpeptidyl mimetics are referred to as GH secretagogues (GHSs). A specific guanosine triphosphatate-binding protein-associated heptahelical transmembrane receptor for GHS was cloned in 1996. An endogenous ligand for the GHS receptor, acylghrelin, was identified in 1999. Expression of ghrelin and homonymous receptor occurs in the brain, pituitary gland, stomach, endothelium/vascular smooth muscle, pancreas, placenta, intestine, heart, bone, and other tissues. Principal actions of this peptidergic system include stimulation of GH release via combined hypothalamopituitary mechanisms, orexigenesis (appetitive enhancement), insulinostasis (inhibition of insulin secretion), cardiovascular effects (decreased mean arterial pressure and vasodilation), stimulation of gastric motility and acid secretion, adipogenesis with repression of fat oxidation, and antiapoptosis (antagonism of endothelial, neuronal, and cardiomyocyte death). The array of known and proposed interactions of ghrelin with key metabolic signals makes ghrelin and its receptor prime targets for drug development.
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Affiliation(s)
- Johannes D. Veldhuis
- Department of Medicine, Endocrine Research Unit, Mayo School of Graduate Medical Education, Clinical Translational Science Center, Mayo Clinic, Rochester, MN 55905, USA
| | - Cyril Y. Bowers
- Division of Endocrinology, Department of Internal Medicine, Tulane University Health Sciences Center, New Orleans, LA 70112, USA
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21
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Chen CY, Asakawa A, Fujimiya M, Lee SD, Inui A. Ghrelin gene products and the regulation of food intake and gut motility. Pharmacol Rev 2010; 61:430-81. [PMID: 20038570 DOI: 10.1124/pr.109.001958] [Citation(s) in RCA: 161] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
A breakthrough using "reverse pharmacology" identified and characterized acyl ghrelin from the stomach as the endogenous cognate ligand for the growth hormone (GH) secretagogue receptor (GHS-R) 1a. The unique post-translational modification of O-n-octanoylation at serine 3 is the first in peptide discovery history and is essential for GH-releasing ability. Des-acyl ghrelin, lacking O-n-octanoylation at serine 3, is also produced in the stomach and remains the major molecular form secreted into the circulation. The third ghrelin gene product, obestatin, a novel 23-amino acid peptide identified from rat stomach, was found by comparative genomic analysis. Three ghrelin gene products actively participate in modulating appetite, adipogenesis, gut motility, glucose metabolism, cell proliferation, immune, sleep, memory, anxiety, cognition, and stress. Knockdown or knockout of acyl ghrelin and/or GHS-R1a, and overexpression of des-acyl ghrelin show benefits in the therapy of obesity and metabolic syndrome. By contrast, agonism of acyl ghrelin and/or GHS-R1a could combat human anorexia-cachexia, including anorexia nervosa, chronic heart failure, chronic obstructive pulmonary disease, liver cirrhosis, chronic kidney disease, burn, and postsurgery recovery, as well as restore gut dysmotility, such as diabetic or neurogenic gastroparesis, and postoperative ileus. The ghrelin acyl-modifying enzyme, ghrelin O-Acyltransferase (GOAT), which attaches octanoate to serine-3 of ghrelin, has been identified and characterized also from the stomach. To date, ghrelin is the only protein to be octanylated, and inhibition of GOAT may have effects only on the stomach and is unlikely to affect the synthesis of other proteins. GOAT may provide a critical molecular target in developing novel therapeutics for obesity and type 2 diabetes.
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Affiliation(s)
- Chih-Yen Chen
- Faculty of Medicine, National Yang-Ming University School of Medicine, Taipei, Japan
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22
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Ren AJ, He Q, Shi JS, Guo ZF, Zheng X, Lin L, Wang YK, Xia SY, Sun LL, Du X, Sun Y, Zhang LM, Yuan WJ. Association of obestatin with blood pressure in the third trimesters of pregnancy. Peptides 2009; 30:1742-5. [PMID: 19560502 DOI: 10.1016/j.peptides.2009.06.016] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2009] [Revised: 06/12/2009] [Accepted: 06/17/2009] [Indexed: 10/20/2022]
Abstract
Obestatin is a recently discovered 23-amino acid peptide encoded by the same gene that encodes ghrelin. It has been reported that there is a significant negative correlation between the plasma ghrelin concentration and systemic blood pressure in patients with pregnancy-induced hypertension. We investigated the plasma concentration of obestatin in 18 non-pregnant women, 18 normal pregnant women, and 15 patients with pregnancy-induced hypertension. The plasma concentrations of obestatin in these 3 groups of women were 63.4+/-9.5pg/ml, 38.1+/-6.3pg/ml, and 46.0+/-9.3pg/ml, respectively. In non-pregnant women, there was no correlation between the plasma obestatin concentration and the mean arterial pressure. However, there was a positive correlation between the plasma obestatin concentration and the mean arterial pressure in normal pregnant women and pregnant women with pregnancy-induced hypertension. These results suggest that obestatin may have some potential role in the regulation of blood pressure in normal pregnant women and women with pregnancy-induced hypertension.
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Affiliation(s)
- An-jing Ren
- Department of Physiology, Second Military Medical University, 800 Xiangyin Road, Shanghai, China
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23
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Dong XY, He JM, Tang SQ, Li HY, Jiang QY, Zou XT. Is GPR39 the natural receptor of obestatin? Peptides 2009; 30:431-8. [PMID: 18977259 DOI: 10.1016/j.peptides.2008.09.022] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2008] [Revised: 08/25/2008] [Accepted: 09/25/2008] [Indexed: 12/15/2022]
Abstract
GPR39, an orphan receptor belonging to the family of G protein-coupled receptors, was originally reported to be the receptor of obestatin. However recently, numerous reports have questioned this conclusion. In mammals, GPR39 was reported to be involved in the regulation of gastrointestinal and the metabolic functions. In this article, a latest and brief review on the receptor family, structure, distribution and physiological functions of GPR39 has been reported.
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Affiliation(s)
- Xiao-Ying Dong
- College of Yingdong Bioengineering, Shaoguan University, Daxue Avenue, Zhenjiang District, Shaoguan 512005, China
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24
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Nunes S, Nogueira-Silva C, Dias E, Moura RS, Correia-Pinto J. Ghrelin and obestatin: different role in fetal lung development? Peptides 2008; 29:2150-8. [PMID: 18789988 DOI: 10.1016/j.peptides.2008.08.012] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2008] [Revised: 08/07/2008] [Accepted: 08/08/2008] [Indexed: 12/28/2022]
Abstract
Ghrelin and obestatin are two proteins that originate from post-translational processing of the preproghrelin peptide. Various authors claim an opposed role of ghrelin and obestatin in several systems. Preproghrelin mRNA is significantly expressed in airway epithelium throughout lung development, predominantly during the earliest stages. The aim of this study was to evaluate the role of ghrelin and obestatin in fetal lung development in vitro. Immunohistochemistry studies were performed at different gestational ages in order to clarify the expression pattern of ghrelin, GHS-R1a, obestatin and GPR39 during fetal lung development. Fetal rat lung explants were harvested at 13.5 days post-conception (dpc) and cultured during 4 days with increasing doses of total ghrelin, acylated ghrelin, desacyl-ghrelin, ghrelin antagonist (D-Lys(3)-GHRP-6) or obestatin. Immunohistochemistry studies demonstrated that ghrelin, GHS-R1a, obestatin and GPR39 proteins were expressed in primitive rat lung epithelium throughout all studied gestational ages. Total and acylated ghrelin supplementation significantly increased the total number of peripheral airway buds, whereas desacyl-ghrelin induced no effect. Moreover, GHS-R1a antagonist significantly decreased lung branching. Finally, obestatin supplementation induced no significant effect in the measured parameters. The present study showed that ghrelin has a positive effect in fetal lung development through its GHS-R1a receptor, whereas obestatin has no effect on lung branching.
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Affiliation(s)
- Susana Nunes
- Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Braga, Portugal
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25
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Soares JB, Leite-Moreira AF. Ghrelin, des-acyl ghrelin and obestatin: three pieces of the same puzzle. Peptides 2008; 29:1255-70. [PMID: 18396350 DOI: 10.1016/j.peptides.2008.02.018] [Citation(s) in RCA: 137] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2008] [Revised: 02/24/2008] [Accepted: 02/26/2008] [Indexed: 12/26/2022]
Abstract
The major active product of ghrelin gene is a 28-amino acid peptide acylated at the serine 3 position with an octanoyl group, called simply ghrelin. Ghrelin has a multiplicity of physiological functions, affecting GH release, food intake, energy and glucose homeostasis, gastrointestinal, cardiovascular, pulmonary and immune function, cell proliferation and differentiation and bone physiology. Nevertheless, recent developments have shown that ghrelin gene can generate various bioactive molecules besides ghrelin, mainly des-acyl ghrelin and obestatin, obtained from alternative splicing or from extensive post-translational modification. Although their receptors have not yet been identified, they have already proven to be active, having intriguingly subtle but opposite physiological actions to ghrelin. This suggests the existence of a novel endocrine system with multiple effector elements which not only may have opposite actions but may regulate the action of each other. In this review, we summarize the steps which lead to the production of the different ghrelin gene products and examine the most significant differences between them in terms of structure and actions.
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Affiliation(s)
- João-Bruno Soares
- Department of Physiology, Faculty of Medicine, University of Porto, 4200-319 Porto, Portugal
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26
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Granata R, Settanni F, Gallo D, Trovato L, Biancone L, Cantaluppi V, Nano R, Annunziata M, Campiglia P, Arnoletti E, Ghè C, Volante M, Papotti M, Muccioli G, Ghigo E. Obestatin promotes survival of pancreatic beta-cells and human islets and induces expression of genes involved in the regulation of beta-cell mass and function. Diabetes 2008; 57:967-79. [PMID: 18162507 DOI: 10.2337/db07-1104] [Citation(s) in RCA: 143] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVE Obestatin is a newly discovered peptide encoded by the ghrelin gene whose biological functions are poorly understood. We investigated obestatin effect on survival of beta-cells and human pancreatic islets and the underlying signaling pathways. RESEARCH DESIGN AND METHODS beta-Cells and human islets were used to assess obestatin effect on cell proliferation, survival, apoptosis, intracellular signaling, and gene expression. RESULTS Obestatin showed specific binding on HIT-T15 and INS-1E beta-cells, bound to glucagon-like peptide-1 receptor (GLP-1R), and recognized ghrelin binding sites. Obestatin exerted proliferative, survival, and antiapoptotic effects under serum-deprived conditions and interferon-gamma/tumor necrosis factor-alpha/interleukin-1 beta treatment, particularly at pharmacological concentrations. Ghrelin receptor antagonist [D-Lys(3)]-growth hormone releasing peptide-6 and anti-ghrelin antibody prevented obestatin-induced survival in beta-cells and human islets. beta-Cells and islet cells released obestatin, and addition of anti-obestatin antibody reduced their viability. Obestatin increased beta-cell cAMP and activated extracellular signal-related kinase 1/2 (ERK1/2) and phosphatidylinositol 3-kinase (PI 3-kinase)/Akt; its antiapoptotic effect was blocked by inhibition of adenylyl cyclase/cAMP/protein kinase A (PKA), PI 3-kinase/Akt, and ERK1/2 signaling. Moreover, obestatin upregulated GLP-1R mRNA and insulin receptor substrate-2 (IRS-2) expression and phosphorylation. The GLP-1R antagonist exendin-(9-39) reduced obestatin effect on beta-cell survival. In human islets, obestatin, whose immunoreactivity colocalized with that of ghrelin, promoted cell survival and blocked cytokine-induced apoptosis through cAMP increase and involvement of adenylyl cyclase/cAMP/PKA signaling. Moreover, obestatin 1) induced PI 3-kinase/Akt, ERK1/2, and also cAMP response element-binding protein phosphorylation; 2) stimulated insulin secretion and gene expression; and 3) upregulated GLP-1R, IRS-2, pancreatic and duodenal homeobox-1, and glucokinase mRNA. CONCLUSIONS These results indicate that obestatin promotes beta-cell and human islet cell survival and stimulates the expression of main regulatory beta-cell genes, identifying a new role for this peptide within the endocrine pancreas.
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Affiliation(s)
- Riccarda Granata
- Laboratory of Molecular and Cellular Endocrinology, Division of Endocrinology and Metabolism, Department of Internal Medicine, University of Turin, Corso Dogliotti, 14-10126 Turin, Italy.
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27
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Tang SQ, Jiang QY, Zhang YL, Zhu XT, Shu G, Gao P, Feng DY, Wang XQ, Dong XY. Obestatin: its physicochemical characteristics and physiological functions. Peptides 2008; 29:639-45. [PMID: 18325633 DOI: 10.1016/j.peptides.2008.01.012] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2007] [Revised: 01/02/2008] [Accepted: 01/04/2008] [Indexed: 12/14/2022]
Abstract
Obestatin, a novel 23 amino acid amidated peptide encoded by the same gene with ghrelin, was initially reported to reduce food intake, body weight gain, gastric emptying and suppress intestinal motility through an interaction with the orphan receptor GPR39. However, recently reports have shown that above findings had been questioned by several groups. Further studies explained that obestatin was involved in inhibiting thirst and anxiety, improving memory, regulating sleep, affecting cell proliferation, and increasing the secretion of pancreatic juice enzymes. We also identified that obestatin could stimulate piglet liver and adipose cell proliferation, and inhibit the secretion of IGF-I. According to the controversy over the effects and the cognate ligand of obestatin, here we provide the latest review on the structure, distribution and physiological functions of obestatin.
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Affiliation(s)
- Sheng-Qiu Tang
- Laboratory of Animal Physiology and Biochemistry, College of Animal Science, South China Agriculture University, Wushan Avenue, Tianhe District, Guangzhou 510642, China
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