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Gupta D, Burstein AW, Schwalbe DC, Shankar K, Varshney S, Singh O, Paul S, Ogden SB, Osborne-Lawrence S, Metzger NP, Richard CP, Campbell JN, Zigman JM. Ghrelin deletion and conditional ghrelin cell ablation increase pancreatic islet size in mice. J Clin Invest 2023; 133:e169349. [PMID: 38099492 PMCID: PMC10721155 DOI: 10.1172/jci169349] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Accepted: 10/05/2023] [Indexed: 12/18/2023] Open
Abstract
Ghrelin exerts key effects on islet hormone secretion to regulate blood glucose levels. Here, we sought to determine whether ghrelin's effects on islets extend to the alteration of islet size and β cell mass. We demonstrate that reducing ghrelin - by ghrelin gene knockout (GKO), conditional ghrelin cell ablation, or high-fat diet (HFD) feeding - was associated with increased mean islet size (up to 62%), percentage of large islets (up to 854%), and β cell cross-sectional area (up to 51%). In GKO mice, these effects were more apparent in 10- to 12-week-old mice than in 4-week-old mice. Higher β cell numbers from decreased β cell apoptosis drove the increase in β cell cross-sectional area. Conditional ghrelin cell ablation in adult mice increased the β cell number per islet by 40% within 4 weeks. A negative correlation between islet size and plasma ghrelin in HFD-fed plus chow-fed WT mice, together with even larger islet sizes in HFD-fed GKO mice than in HFD-fed WT mice, suggests that reduced ghrelin was not solely responsible for diet-induced obesity-associated islet enlargement. Single-cell transcriptomics revealed changes in gene expression in several GKO islet cell types, including upregulation of Manf, Dnajc3, and Gnas expression in β cells, which supports decreased β cell apoptosis and/or increased β cell proliferation. These effects of ghrelin reduction on islet morphology might prove useful when designing new therapies for diabetes.
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Affiliation(s)
- Deepali Gupta
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Avi W. Burstein
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Dana C. Schwalbe
- Department of Biology, University of Virginia, Charlottesville, Virginia, USA
| | - Kripa Shankar
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Salil Varshney
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Omprakash Singh
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Subhojit Paul
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Sean B. Ogden
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Sherri Osborne-Lawrence
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Nathan P. Metzger
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas, USA
| | - Corine P. Richard
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas, USA
| | - John N. Campbell
- Department of Biology, University of Virginia, Charlottesville, Virginia, USA
| | - Jeffrey M. Zigman
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, Texas, USA
- Division of Endocrinology and Metabolism, Department of Internal Medicine and
- Department of Psychiatry, UT Southwestern Medical Center, Dallas, Texas, USA
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Tatum SM, Holland WL. Germline and conditional ghrelin knockout increases islet size. J Clin Invest 2023; 133:e175799. [PMID: 38099493 PMCID: PMC10721140 DOI: 10.1172/jci175799] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2023] Open
Abstract
Conflicting studies in recent years report that genetic or pharmacological increases or decreases in ghrelin either increase or have no effect on islet size. In this issue of the JCI, Gupta, Burstein, and colleagues applied a rigorous approach to determine the effects of reducing ghrelin on islet size in germline and conditional ghrelin-knockout mice as well as across varying ages and weight. Both germline and conditional ghrelin-knockout mice associated with increased islet size, which was further exacerbated by older age and diet-induced obesity. These findings suggest that modulation of ghrelin may open a therapeutic window to prevent or treat diabetes.
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Liang Y, Yin W, Yin Y, Zhang W. Ghrelin Based Therapy of Metabolic Diseases. Curr Med Chem 2021; 28:2565-2576. [PMID: 32538716 DOI: 10.2174/0929867327666200615152804] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 05/04/2020] [Accepted: 05/18/2020] [Indexed: 11/22/2022]
Abstract
BACKGROUND Ghrelin, a unique 28 amino acid peptide hormone secreted by the gastric X/A like cells, is an endogenous ligand of the growth hormone secretagogue receptor (GHSR). Ghrelin-GHSR signaling has been found to exert various physiological functions, including stimulation of appetite, regulation of body weight, lipid and glucose metabolism, and increase of gut motility and secretion. This system is thus critical for energy homeostasis. OBJECTIVE The objective of this review is to highlight the strategies of ghrelin-GHSR based intervention for therapy of obesity and its related metabolic diseases. RESULTS Therapeutic strategies of metabolic disorders targeting the ghrelin-GHSR pathway involve neutralization of circulating ghrelin by antibodies and RNA spiegelmers, antagonism of ghrelin receptor by its antagonists and inverse agonists, inhibition of ghrelin O-acyltransferase (GOAT), as well as potential pharmacological approach to decrease ghrelin synthesis and secretion. CONCLUSION Various compounds targeting the ghrelin-GHSR system have shown promising efficacy for the intervention of obesity and relevant metabolic disorders in animals and in vitro. Further clinical trials to validate their efficacy in human beings are urgently needed.
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Affiliation(s)
- Yuan Liang
- Key Laboratory of Molecular Cardiovascular Science, Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Wenzhen Yin
- Key Laboratory of Molecular Cardiovascular Science, Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Yue Yin
- Key Laboratory of Molecular Cardiovascular Science, Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Weizhen Zhang
- Key Laboratory of Molecular Cardiovascular Science, Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
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Kaiser J, Krippeit-Drews P, Drews G. Acyl-Ghrelin Influences Pancreatic β-Cell Function by Interference with K ATP Channels. Diabetes 2021; 70:423-435. [PMID: 33154069 DOI: 10.2337/db20-0231] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Accepted: 11/03/2020] [Indexed: 11/13/2022]
Abstract
The aim for this study was to elucidate how the hypothalamic hunger-inducing hormone acyl-ghrelin (AG), which is also produced in the pancreas, affects β-cell function, with particular attention to the role of ATP-sensitive K+ (KATP) channels and the exact site of action of the hormone. AG hyperpolarized the membrane potential and decreased cytoplasmic calcium concentration [Ca2+]c and glucose-stimulated insulin secretion (GSIS). These effects were abolished in β-cells from SUR1-knockout (KO) mice. AG increased KATP current but only in a configuration with intact metabolism. Unacylated ghrelin counteracted the effects of AG. The influence of AG on membrane potential and GSIS could only be averted in the combined presence of a ghrelin receptor (GHSR1a) antagonist and an inverse agonist. The inhibition of GSIS by AG could be prevented by dibutyryl cyclic-cAMP or 3-isobutyl-1-methylxanthine and the somatostatin (SST) receptor 2-5 antagonist H6056. These data indicate that AG indirectly opens KATP channels probably by interference with the cAMP/cAMP-dependent protein kinase pathway, resulting in a decrease of [Ca2+]c and GSIS. The experiments with SUR1-KO β-cells point to a direct effect of AG on β-cells and not, as earlier suggested, to an exclusive effect by AG-induced SST release from δ-cells. Nevertheless, SST receptors may be involved in the effect of AG, possibly by heteromerization of AG and SST receptors.
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Affiliation(s)
- Julia Kaiser
- Department of Pharmacology, Institute of Pharmacy, University of Tübingen, Tübingen, Germany
| | - Peter Krippeit-Drews
- Department of Pharmacology, Institute of Pharmacy, University of Tübingen, Tübingen, Germany
| | - Gisela Drews
- Department of Pharmacology, Institute of Pharmacy, University of Tübingen, Tübingen, Germany
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Alhabeeb H, AlFaiz A, Kutbi E, AlShahrani D, Alsuhail A, AlRajhi S, Alotaibi N, Alotaibi K, AlAmri S, Alghamdi S, AlJohani N. Gut Hormones in Health and Obesity: The Upcoming Role of Short Chain Fatty Acids. Nutrients 2021; 13:nu13020481. [PMID: 33572661 PMCID: PMC7911102 DOI: 10.3390/nu13020481] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2020] [Revised: 12/21/2020] [Accepted: 12/30/2020] [Indexed: 12/13/2022] Open
Abstract
We are currently facing an obesity pandemic, with worldwide obesity rates having tripled since 1975. Obesity is one of the main risk factors for the development of non-communicable diseases, which are now the leading cause of death worldwide. This calls for urgent action towards understanding the underlying mechanisms behind the development of obesity as well as developing more effective treatments and interventions. Appetite is carefully regulated in humans via the interaction between the central nervous system and peripheral hormones. This involves a delicate balance in external stimuli, circulating satiating and appetite stimulating hormones, and correct functioning of neuronal signals. Any changes in this equilibrium can lead to an imbalance in energy intake versus expenditure, which often leads to overeating, and potentially weight gain resulting in overweight or obesity. Several lines of research have shown imbalances in gut hormones are found in those who are overweight or obese, which may be contributing to their condition. Therefore, this review examines the evidence for targeting gut hormones in the treatment of obesity by discussing how their dysregulation influences food intake, the potential possibility of altering the circulating levels of these hormones for treating obesity, as well as the role of short chain fatty acids and protein as novel treatments.
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Affiliation(s)
- Habeeb Alhabeeb
- Research Center, King Fahad Medical City—KFMC, Riyadh 11525, Saudi Arabia; (A.A.); (E.K.); (D.A.); (A.A.); (S.A.); (S.A.)
- Correspondence:
| | - Ali AlFaiz
- Research Center, King Fahad Medical City—KFMC, Riyadh 11525, Saudi Arabia; (A.A.); (E.K.); (D.A.); (A.A.); (S.A.); (S.A.)
| | - Emad Kutbi
- Research Center, King Fahad Medical City—KFMC, Riyadh 11525, Saudi Arabia; (A.A.); (E.K.); (D.A.); (A.A.); (S.A.); (S.A.)
| | - Dayel AlShahrani
- Research Center, King Fahad Medical City—KFMC, Riyadh 11525, Saudi Arabia; (A.A.); (E.K.); (D.A.); (A.A.); (S.A.); (S.A.)
| | - Abdullah Alsuhail
- Research Center, King Fahad Medical City—KFMC, Riyadh 11525, Saudi Arabia; (A.A.); (E.K.); (D.A.); (A.A.); (S.A.); (S.A.)
| | - Saleh AlRajhi
- Family Medicine, King Fahad Medical City—KFMC, Riyadh 11525, Saudi Arabia;
| | - Nemer Alotaibi
- College of Medicine, Shaqra University, Shaqra 11961, Saudi Arabia; (N.A.); (K.A.)
| | - Khalid Alotaibi
- College of Medicine, Shaqra University, Shaqra 11961, Saudi Arabia; (N.A.); (K.A.)
| | - Saad AlAmri
- Research Center, King Fahad Medical City—KFMC, Riyadh 11525, Saudi Arabia; (A.A.); (E.K.); (D.A.); (A.A.); (S.A.); (S.A.)
| | - Saleh Alghamdi
- Research Center, King Fahad Medical City—KFMC, Riyadh 11525, Saudi Arabia; (A.A.); (E.K.); (D.A.); (A.A.); (S.A.); (S.A.)
| | - Naji AlJohani
- Obesity, Endocrine, and Metabolism Center, King Fahad Medical City—KFMC, Riyadh 11525, Saudi Arabia;
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Dagher-Hamalian C, Stephan J, Zeeni N, Harhous Z, Shebaby WN, Abdallah MS, Faour WH. Ghrelin-induced multi-organ damage in mice fed obesogenic diet. Inflamm Res 2020; 69:1019-1026. [PMID: 32719925 DOI: 10.1007/s00011-020-01383-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 07/13/2020] [Accepted: 07/16/2020] [Indexed: 02/08/2023] Open
Abstract
OBJECTIVE AND DESIGN Ghrelin has a key role in modulating energy metabolism and weight gain. The present study aimed at studying the potential role of ghrelin in the development and/or exacerbation of organ damage in a mouse model of diet-induced obesity. OBJECTIVE AND DESIGN Adult mice were fed one of two diets for 20 weeks: standard high carbohydrate (HC) or high-fat high-sugar (HFHS). Starting week 17, the animals were given regular intraperitoneal ghrelin (160 µg/kg) or saline injections Abdominal fat, serum creatinine, and glucose levels, as well as kidney, liver and heart weight and pathology were assessed. RESULTS Ghrelin-injected mice showed significant organ damage, which was more exacerbated in HFHS-fed animals. While the HFHS diet was associated with significant liver damage, ghrelin administration did not reverse it. Interestingly, ghrelin administration induced moderate kidney damage and significantly affected the heart by increasing perivascular and myocardium fibrosis, steatosis as well as inflammation. Moreover, serum creatinine levels were higher in the animal group injected with ghrelin. CONCLUSION Ghrelin administration was associated with increased functional and structural organ damage, regardless of diet. The present study provides novel evidence of multi-organ physiologic alterations secondary to ghrelin administration.
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Affiliation(s)
- Carole Dagher-Hamalian
- Gilbert and Rose-Marie Chagoury School of Medicine, Lebanese American University, PO Box 36, Byblos, Lebanon
| | - Joseph Stephan
- Gilbert and Rose-Marie Chagoury School of Medicine, Lebanese American University, PO Box 36, Byblos, Lebanon
| | - Nadine Zeeni
- Department of Natural Sciences, School of Arts and Sciences, Lebanese American University, PO Box 36, Byblos, Lebanon
| | - Zeina Harhous
- Gilbert and Rose-Marie Chagoury School of Medicine, Lebanese American University, PO Box 36, Byblos, Lebanon
| | - Wassim N Shebaby
- Department of Natural Sciences, School of Arts and Sciences, Lebanese American University, PO Box 36, Byblos, Lebanon
| | - Maya S Abdallah
- Gilbert and Rose-Marie Chagoury School of Medicine, Lebanese American University, PO Box 36, Byblos, Lebanon
| | - Wissam H Faour
- Gilbert and Rose-Marie Chagoury School of Medicine, Lebanese American University, PO Box 36, Byblos, Lebanon.
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Ishioh M, Nozu T, Igarashi S, Tanabe H, Kumei S, Ohhira M, Okumura T. Ghrelin acts in the brain to block colonic hyperpermeability in response to lipopolysaccharide through the vagus nerve. Neuropharmacology 2020; 173:108116. [PMID: 32442542 DOI: 10.1016/j.neuropharm.2020.108116] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 04/23/2020] [Accepted: 04/26/2020] [Indexed: 12/31/2022]
Abstract
Brain ghrelin plays a role in gastrointestinal functions. Among them, ghrelin acts centrally to stimulate gastrointestinal motility and induce visceral antinociception. Intestinal barrier function, one of important gastrointestinal functions, is also controlled by the central nervous system. Little is, however, known about a role of central ghrelin in regulation of intestinal permeability. The present study was performed to clarify whether brain ghrelin is also involved in regulation of intestinal barrier function and its mechanism. Colonic permeability was estimated in vivo by quantifying the absorbed Evans blue in colonic tissue in rats. Intracisternal injection of ghrelin dose-dependently abolished increased colonic permeability in response to LPS while intraperitoneal injection of ghrelin at the same dose or intracisternal injection of des-acyl-ghrelin failed to block it. Carbachol potently attenuated LPS-induced intestinal hyperpermeability, and atropine or bilateral subdiaphragmatic vagotomy prevented the improvement of intestinal hyperpermeability by central ghrelin. Intracisternal (D-Lys3)-GHRP-6, a selective ghrelin receptor antagonist, significantly blocked improvement of intestinal barrier function by intravenously administered 2-deoxy-d-glucose, central vagal stimulant. Intracisternal injection of orexin 1 receptor antagonist, SB-334867 blocked intracisternal ghrelin-induced improvement of colonic hyperpermeability. These results suggest that exogenously administered or endogenously released ghrelin acts centrally to improve a disturbed intestinal barrier function through orexinergic signaling and the vagal cholinergic pathway. Central ghrelin may be involved in the pathophysiology and be a novel therapeutic option in not only gastrointestinal diseases such as irritable bowel syndrome but also non-gastrointestinal diseases associated with the altered intestinal permeability.
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Affiliation(s)
- Masatomo Ishioh
- Division of Gastroenterology and Hematology/Oncology, Department of Medicine, Asahikawa Medical University, Japan; Department of General Medicine, Asahikawa Medical University, Japan
| | - Tsukasa Nozu
- Department of Regional Medicine and Education, Asahikawa Medical University, Japan
| | - Sho Igarashi
- Division of Gastroenterology and Hematology/Oncology, Department of Medicine, Asahikawa Medical University, Japan
| | - Hiroki Tanabe
- Division of Gastroenterology and Hematology/Oncology, Department of Medicine, Asahikawa Medical University, Japan
| | - Shima Kumei
- Department of General Medicine, Asahikawa Medical University, Japan
| | - Masumi Ohhira
- Department of General Medicine, Asahikawa Medical University, Japan
| | - Toshikatsu Okumura
- Division of Gastroenterology and Hematology/Oncology, Department of Medicine, Asahikawa Medical University, Japan; Department of General Medicine, Asahikawa Medical University, Japan.
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Huang L, Huang Z, Chen C. Rhythmic growth hormone secretion in physiological and pathological conditions: Lessons from rodent studies. Mol Cell Endocrinol 2019; 498:110575. [PMID: 31499134 DOI: 10.1016/j.mce.2019.110575] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Revised: 09/04/2019] [Accepted: 09/04/2019] [Indexed: 02/01/2023]
Abstract
Evolutionally conserved in all mammalians, the release of GH occurs in a rhythmic pattern, characterized by several dominant surges (pulsatile GH) with tonic low inter-pulse levels (tonic GH). Such pulsatile secretion pattern is essential for many physiological actions of GH on different tissues with defined gender dimorphism. Rhythmic release of pulsatile GH is tightly controlled by hypothalamic neurons as well as peripheral metabolic factors. Changes of GH pattern occur within a range of sophisticated physiological and pathological settings and significantly contribute to growth, ageing, survival and disease predispositions. Precise analysis of GH secretion pattern is vitally important for a comprehensive understanding of the function of GH and the components that regulate GH secretion pattern.
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Affiliation(s)
- Lili Huang
- School of Biomedical Sciences, University of Queensland, St Lucia, Brisbane, Australia
| | - Zhengxiang Huang
- School of Biomedical Sciences, University of Queensland, St Lucia, Brisbane, Australia
| | - Chen Chen
- School of Biomedical Sciences, University of Queensland, St Lucia, Brisbane, Australia.
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Abstract
PURPOSE OF REVIEW Obesity is affecting over 600 million adults worldwide and has numerous negative effects on health. Since ghrelin positively regulates food intake and body weight, targeting its signaling to induce weight loss under conditions of obesity seems promising. Thus, the present work reviews and discusses different possibilities to alter ghrelin signaling. RECENT FINDINGS Ghrelin signaling can be altered by RNA Spiegelmers, GHSR/Fc, ghrelin-O-acyltransferase inhibitors as well as antagonists, and inverse agonists of the ghrelin receptor. PF-05190457 is the first inverse agonist of the ghrelin receptor tested in humans shown to inhibit growth hormone secretion, gastric emptying, and reduce postprandial glucose levels. Effects on body weight were not examined. Although various highly promising agents targeting ghrelin signaling exist, so far, they were mostly only tested in vitro or in animal models. Further research in humans is thus needed to further assess the effects of ghrelin antagonism on body weight especially under conditions of obesity.
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Affiliation(s)
- Martha A Schalla
- Charité Center for Internal Medicine and Dermatology, Charité Center for Internal Medicine and Dermatology, Department for Psychosomatic Medicine; Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Andreas Stengel
- Charité Center for Internal Medicine and Dermatology, Charité Center for Internal Medicine and Dermatology, Department for Psychosomatic Medicine; Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.
- Department of Psychosomatic Medicine and Psychotherapy, Medical University Hospital Tübingen, Tübingen, Germany.
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Maugham ML, Seim I, Thomas PB, Crisp GJ, Shah ET, Herington AC, Gregory LS, Nelson CC, Jeffery PL, Chopin LK. Limited short-term effects on human prostate cancer xenograft growth and epidermal growth factor receptor gene expression by the ghrelin receptor antagonist [D-Lys 3]-GHRP-6. Endocrine 2019; 64:393-405. [PMID: 30390209 DOI: 10.1007/s12020-018-1796-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2018] [Accepted: 10/17/2018] [Indexed: 12/15/2022]
Abstract
PURPOSE The ghrelin axis regulates many physiological functions (including appetite, metabolism, and energy balance) and plays a role in disease processes. As ghrelin stimulates prostate cancer proliferation, the ghrelin receptor antagonist [D-Lys3]-GHRP-6 is a potential treatment for castrate-resistant prostate cancer and for preventing the metabolic consequences of androgen-targeted therapies. We therefore explored the effect of [D-Lys3]-GHRP-6 on PC3 prostate cancer xenograft growth. METHODS NOD/SCID mice with PC3 prostate cancer xenografts were administered 20 nmoles/mouse [D-Lys3]-GHRP-6 daily by intraperitoneal injection for 14 days and tumour volume and weight were measured. RNA sequencing of tumours was conducted to investigate expression changes following [D-Lys3]-GHRP-6 treatment. A second experiment, extending treatment time to 18 days and including a higher dose of [D-Lys3]-GHRP-6 (200 nmoles/mouse/day), was undertaken to ensure repeatability. RESULTS We demonstrate here that daily intraperitoneal injection of 20 nmoles/mouse [D-Lys3]-GHRP-6 reduces PC3 prostate cancer xenograft tumour volume and weight in NOD/SCID mice at two weeks post treatment initiation. RNA-sequencing revealed reduced expression of epidermal growth factor receptor (EGFR) in these tumours. Further experiments demonstrated that the effects of [D-Lys3]-GHRP-6 are transitory and lost after 18 days of treatment. CONCLUSIONS We show that [D-Lys3]-GHRP-6 has transitory effects on prostate xenograft tumours in mice, which rapidly develop an apparent resistance to the antagonist. Although further studies on [D-Lys3]-GHRP-6 are warranted, we suggest that daily treatment with the antagonist is not a suitable treatment for advanced prostate cancer.
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Affiliation(s)
- Michelle L Maugham
- Ghrelin Research Group, Institute of Health and Biomedical Innovation, Translational Research Institute and School of Biomedical Sciences, Queensland University of Technology, Brisbane, QLD, Australia
- Australian Prostate Cancer Research Centre - Queensland, Princess Alexandra Hospital, Institute of Health and Biomedical Innovation, Translational Research Institute, Queensland University of Technology, Brisbane, QLD, Australia
- Comparative and Endocrine Biology Laboratory, Institute of Health and Biomedical Innovation, Translational Research Institute, Queensland University of Technology, Brisbane, QLD, Australia
- Skeletal Biology and Forensic Anthropology Research Laboratory, Cancer Program, School of Biomedical Sciences, Institute of Health and Biomedical Innovation, Translational Research Institute, Queensland University of Technology, Brisbane, QLD, Australia
| | - Inge Seim
- Ghrelin Research Group, Institute of Health and Biomedical Innovation, Translational Research Institute and School of Biomedical Sciences, Queensland University of Technology, Brisbane, QLD, Australia
- Australian Prostate Cancer Research Centre - Queensland, Princess Alexandra Hospital, Institute of Health and Biomedical Innovation, Translational Research Institute, Queensland University of Technology, Brisbane, QLD, Australia
- Comparative and Endocrine Biology Laboratory, Institute of Health and Biomedical Innovation, Translational Research Institute, Queensland University of Technology, Brisbane, QLD, Australia
- Integrative Biology Laboratory, College of Life Sciences, Nanjing Normal University, Nanjing, Jiangsu, China
| | - Patrick B Thomas
- Ghrelin Research Group, Institute of Health and Biomedical Innovation, Translational Research Institute and School of Biomedical Sciences, Queensland University of Technology, Brisbane, QLD, Australia
- Australian Prostate Cancer Research Centre - Queensland, Princess Alexandra Hospital, Institute of Health and Biomedical Innovation, Translational Research Institute, Queensland University of Technology, Brisbane, QLD, Australia
- Comparative and Endocrine Biology Laboratory, Institute of Health and Biomedical Innovation, Translational Research Institute, Queensland University of Technology, Brisbane, QLD, Australia
| | - Gabrielle J Crisp
- Ghrelin Research Group, Institute of Health and Biomedical Innovation, Translational Research Institute and School of Biomedical Sciences, Queensland University of Technology, Brisbane, QLD, Australia
- Australian Prostate Cancer Research Centre - Queensland, Princess Alexandra Hospital, Institute of Health and Biomedical Innovation, Translational Research Institute, Queensland University of Technology, Brisbane, QLD, Australia
- Comparative and Endocrine Biology Laboratory, Institute of Health and Biomedical Innovation, Translational Research Institute, Queensland University of Technology, Brisbane, QLD, Australia
| | - Esha T Shah
- Ghrelin Research Group, Institute of Health and Biomedical Innovation, Translational Research Institute and School of Biomedical Sciences, Queensland University of Technology, Brisbane, QLD, Australia
- Australian Prostate Cancer Research Centre - Queensland, Princess Alexandra Hospital, Institute of Health and Biomedical Innovation, Translational Research Institute, Queensland University of Technology, Brisbane, QLD, Australia
- Comparative and Endocrine Biology Laboratory, Institute of Health and Biomedical Innovation, Translational Research Institute, Queensland University of Technology, Brisbane, QLD, Australia
| | - Adrian C Herington
- Ghrelin Research Group, Institute of Health and Biomedical Innovation, Translational Research Institute and School of Biomedical Sciences, Queensland University of Technology, Brisbane, QLD, Australia
- Australian Prostate Cancer Research Centre - Queensland, Princess Alexandra Hospital, Institute of Health and Biomedical Innovation, Translational Research Institute, Queensland University of Technology, Brisbane, QLD, Australia
| | - Laura S Gregory
- Skeletal Biology and Forensic Anthropology Research Laboratory, Cancer Program, School of Biomedical Sciences, Institute of Health and Biomedical Innovation, Translational Research Institute, Queensland University of Technology, Brisbane, QLD, Australia
| | - Colleen C Nelson
- Australian Prostate Cancer Research Centre - Queensland, Princess Alexandra Hospital, Institute of Health and Biomedical Innovation, Translational Research Institute, Queensland University of Technology, Brisbane, QLD, Australia
| | - Penny L Jeffery
- Ghrelin Research Group, Institute of Health and Biomedical Innovation, Translational Research Institute and School of Biomedical Sciences, Queensland University of Technology, Brisbane, QLD, Australia
- Australian Prostate Cancer Research Centre - Queensland, Princess Alexandra Hospital, Institute of Health and Biomedical Innovation, Translational Research Institute, Queensland University of Technology, Brisbane, QLD, Australia
- Comparative and Endocrine Biology Laboratory, Institute of Health and Biomedical Innovation, Translational Research Institute, Queensland University of Technology, Brisbane, QLD, Australia
| | - Lisa K Chopin
- Ghrelin Research Group, Institute of Health and Biomedical Innovation, Translational Research Institute and School of Biomedical Sciences, Queensland University of Technology, Brisbane, QLD, Australia.
- Australian Prostate Cancer Research Centre - Queensland, Princess Alexandra Hospital, Institute of Health and Biomedical Innovation, Translational Research Institute, Queensland University of Technology, Brisbane, QLD, Australia.
- Comparative and Endocrine Biology Laboratory, Institute of Health and Biomedical Innovation, Translational Research Institute, Queensland University of Technology, Brisbane, QLD, Australia.
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Sun X, Yi Y, Liang B, Yang Y, He N, Ode KL, Uc A, Wang K, Gibson-Corley KN, Engelhardt JF, Norris AW. Incretin dysfunction and hyperglycemia in cystic fibrosis: Role of acyl-ghrelin. J Cyst Fibros 2019; 18:557-565. [PMID: 30738804 DOI: 10.1016/j.jcf.2019.01.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Revised: 01/05/2019] [Accepted: 01/21/2019] [Indexed: 12/25/2022]
Abstract
BACKGROUND Insulin secretion is insufficient in cystic fibrosis (CF), even before diabetes is present, though the mechanisms involved remain unclear. Acyl-ghrelin (AG) can diminish insulin secretion and is elevated in humans with CF. METHODS We tested the hypothesis that elevated AG contributes to reduced insulin secretion and hyperglycemia in CF ferrets. RESULTS Fasting AG was elevated in CF versus non-CF ferrets. Similar to its effects in other species, AG administration in non-CF ferrets acutely reduced insulin, increased growth hormone, and induced hyperglycemia. During oral glucose tolerance testing, non-CF ferrets had responsive insulin, glucagon like peptide-1 (GLP-1) and gastric inhibitory polypeptide (GIP) levels and maintained normal glucose levels, whereas CF ferrets had insufficient responses and became hyperglycemic. Interestingly in wild-type ferrets, the acyl-ghrelin receptor antagonist [D-Lys3]-GHRP-6 impaired glucose tolerance, and abolished insulin, GLP-1, and GIP responses during glucose tolerance testing. By contrast, in CF ferrets [D-Lys3]-GHRP-6 improved glucose tolerance, enhanced the insulin-to-glucose ratio, but did not impact the already low GLP-1 and GIP levels. CONCLUSIONS These results suggest a mechanism by which elevated AG contributes to CF hyperglycemia through inhibition of insulin secretion, an effect magnified by low GLP-1 and GIP. Interventions that lower ghrelin, ghrelin action, and/or raise GLP-1 or GIP might improve glycemia in CF.
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Affiliation(s)
- Xingshen Sun
- Department of Anatomy and Cell Biology, University of Iowa, Iowa City, IA 52242, USA
| | - Yaling Yi
- Department of Anatomy and Cell Biology, University of Iowa, Iowa City, IA 52242, USA
| | - Bo Liang
- Department of Anatomy and Cell Biology, University of Iowa, Iowa City, IA 52242, USA
| | - Yu Yang
- Department of Anatomy and Cell Biology, University of Iowa, Iowa City, IA 52242, USA
| | - Nan He
- Department of Anatomy and Cell Biology, University of Iowa, Iowa City, IA 52242, USA
| | - Katie Larson Ode
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA 52242, USA; Department of Pediatrics, University of Iowa, Iowa City, IA 52242, USA
| | - Aliye Uc
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA 52242, USA; Department of Pediatrics, University of Iowa, Iowa City, IA 52242, USA
| | - Kai Wang
- Department of Biostatistics, University of Iowa, Iowa City, IA 52242, USA
| | - Katherine N Gibson-Corley
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA 52242, USA; Department of Pathology, University of Iowa, Iowa City, IA 52242, USA
| | - John F Engelhardt
- Department of Anatomy and Cell Biology, University of Iowa, Iowa City, IA 52242, USA; Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA 52242, USA.
| | - Andrew W Norris
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA 52242, USA; Department of Pediatrics, University of Iowa, Iowa City, IA 52242, USA; Department of Biochemistry, University of Iowa, Iowa City, IA 52242, USA.
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Ramirez VT, van Oeffelen WEPA, Torres-Fuentes C, Chruścicka B, Druelle C, Golubeva AV, van de Wouw M, Dinan TG, Cryan JF, Schellekens H. Differential functional selectivity and downstream signaling bias of ghrelin receptor antagonists and inverse agonists. FASEB J 2018; 33:518-531. [PMID: 30020830 DOI: 10.1096/fj.201800655r] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The ghrelin receptor [growth hormone secretagogue receptor (GHSR)-1a] represents a promising pharmacologic target for the treatment of metabolic disorders, including obesity and cachexia, via central appetite modulation. The GHSR-1a has a complex pharmacology, highlighted by G-protein-dependent and -independent downstream signaling pathways and high basal constitutive activity. The functional selectivity and signaling bias of many GHSR-1a-specific ligands has not been fully characterized. In this study, we investigated the pharmacologic properties of ghrelin, MK-0677, L692,585, and [d-Lys3]-growth hormone-releasing peptide-6 (Dlys), JMV2959, and [d-Arg(1),d-Phe(5),d-Trp(7, 9),Leu(11)]-substance P (SP-analog). We investigated their effect on basal GHSR-1a constitutive signaling, ligand-directed downstream GHSR-1a signaling, functional selectivity, and signaling bias. Dlys behaved as a partial antagonist with a strong bias toward GHSR-1a-β-arrestin signaling, whereas JMV2959 acted as a full unbiased GHSR-1a antagonist. Moreover, the SP-analog behaved as an inverse agonist increasing G-protein-dependent signaling, but only at high concentrations, whereas, at low concentrations, the SP-analog attenuated β-arrestin-dependent signaling. Considering the limited success in the clinical development of GHSR-1a-targeted drugs so far, these findings provide a novel insight into the pharmacologic characteristics of GHSR-1a ligands and their signaling bias, which has important implications in the design of novel, more selective GHSR-1a ligands with predictable functional outcome and selectivity for preclinical and clinical drug development.-Ramirez, V. T., van Oeffelen, W. E. P. A., Torres-Fuentes, C., Chruścicka, B., Druelle, C., Golubeva, A. V., van de Wouw, M., Dinan, T. G., Cryan, J. F., Schellekens, H. Differential functional selectivity and downstream signaling bias of ghrelin receptor antagonists and inverse agonists.
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Affiliation(s)
- Valerie T Ramirez
- Alimentary Pharmabiotic Centre (APC) Microbiome Ireland, University College Cork, Cork, Ireland
| | | | - Cristina Torres-Fuentes
- Alimentary Pharmabiotic Centre (APC) Microbiome Ireland, University College Cork, Cork, Ireland
| | - Barbara Chruścicka
- Alimentary Pharmabiotic Centre (APC) Microbiome Ireland, University College Cork, Cork, Ireland
| | - Clementine Druelle
- Alimentary Pharmabiotic Centre (APC) Microbiome Ireland, University College Cork, Cork, Ireland
| | - Anna V Golubeva
- Alimentary Pharmabiotic Centre (APC) Microbiome Ireland, University College Cork, Cork, Ireland
| | - Marcel van de Wouw
- Alimentary Pharmabiotic Centre (APC) Microbiome Ireland, University College Cork, Cork, Ireland.,Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland
| | - Timothy G Dinan
- Alimentary Pharmabiotic Centre (APC) Microbiome Ireland, University College Cork, Cork, Ireland.,Department of Psychiatry, University College Cork, Cork, Ireland; and
| | - John F Cryan
- Alimentary Pharmabiotic Centre (APC) Microbiome Ireland, University College Cork, Cork, Ireland.,Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland.,Food for Health Ireland, University College Cork, Cork, Ireland
| | - Harriët Schellekens
- Alimentary Pharmabiotic Centre (APC) Microbiome Ireland, University College Cork, Cork, Ireland.,Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland.,Food for Health Ireland, University College Cork, Cork, Ireland
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