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Hayakawa S, Tanaka T, Ogawa R, Ito S, Ueno S, Koyama H, Tomotaka O, Sagawa H, Tanaka T, Iwakura H, Takahashi H, Matsuo Y, Mitsui A, Kimura M, Takahashi S, Takiguchi S. Potential Role of TRPV4 in Stretch-Induced Ghrelin Secretion and Obesity. Int J Endocrinol 2022; 2022:7241275. [PMID: 36397882 PMCID: PMC9666045 DOI: 10.1155/2022/7241275] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 10/18/2022] [Accepted: 10/25/2022] [Indexed: 11/09/2022] Open
Abstract
Obesity is an important health problem, which can be prevented through appetite control. Ghrelin is an appetite-stimulating hormone considered to promote obesity. Thus, we examined whether gastric stretching affects ghrelin secretion. We investigated the role of transient receptor potential vanilloid 4 (TRPV4) in gastric glands in the regulation of ghrelin secretion. TRPV4 immunostaining was performed in tissue samples from 57 patients who underwent gastrectomy. TRPV4 expression was compared between patients with (body mass index (BMI) ≥ 30) and without (BMI <30) obesity. For in vitro experiments, we used MGN3-1 cells, a ghrelin-producing cell line derived from mice. To investigate the bioactivity of TRPV4, MGN3-1 cells were treated with TRPV4 agonists and antagonists, and changes in intracellular Ca2+ concentration were confirmed. The concentration of ghrelin in the cell supernatant was measured using the ELISA with and without 120% stretch stimulation. TRPV4 expression was significantly higher in patients with obesity than in those without at all sites, except the fornix. Immunostaining confirmed the expression of TRPV4 in MGN3-1 cells. TRPV4 agonist administration increased intracellular Ca2+ concentration and ghrelin secretion in MGN3-1 cells, whereas the administration of the agonist combined with the antagonist decreased intracellular Ca2+ concentration and ghrelin secretion. Ghrelin secretion significantly increased in response to a 120% stretch in MGN3-1 cells. However, secretion was not increased by stretch when cells were treated with a TRPV4 antagonist. TRPV4 regulates ghrelin secretion in response to stretch in the stomach, which may affect body weight.
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Affiliation(s)
- Shunsuke Hayakawa
- Department of Gastroenterological Surgery, Nagoya City University Graduate School of Medical Sciences, Nagoya, Aichi, Japan
| | - Tatsuya Tanaka
- Department of Gastroenterological Surgery, Nagoya City University Graduate School of Medical Sciences, Nagoya, Aichi, Japan
| | - Ryo Ogawa
- Department of Gastroenterological Surgery, Nagoya City University Graduate School of Medical Sciences, Nagoya, Aichi, Japan
| | - Sunao Ito
- Department of Gastroenterological Surgery, Nagoya City University Graduate School of Medical Sciences, Nagoya, Aichi, Japan
| | - Shuhei Ueno
- Department of Gastroenterological Surgery, Nagoya City University Graduate School of Medical Sciences, Nagoya, Aichi, Japan
| | - Hiroyuki Koyama
- Department of Gastroenterology and Metabolism, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Okubo Tomotaka
- Department of Gastroenterological Surgery, Nagoya City University Graduate School of Medical Sciences, Nagoya, Aichi, Japan
| | - Hiroyuki Sagawa
- Department of Gastroenterological Surgery, Nagoya City University Graduate School of Medical Sciences, Nagoya, Aichi, Japan
| | - Tomohiro Tanaka
- Department of Gastroenterology and Metabolism, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan
| | - Hiroshi Iwakura
- Department of Pharmacotherapeutics, Wakayama Medical University, Kimiidera, Wakayama, Wakayama, Japan
| | - Hiroki Takahashi
- Department of Gastroenterological Surgery, Nagoya City University Graduate School of Medical Sciences, Nagoya, Aichi, Japan
| | - Yoichi Matsuo
- Department of Gastroenterological Surgery, Nagoya City University Graduate School of Medical Sciences, Nagoya, Aichi, Japan
| | - Akira Mitsui
- Department of Gastroenterological Surgery, Nagoya City University Graduate School of Medical Sciences, Nagoya, Aichi, Japan
| | - Masahiro Kimura
- Department of Gastroenterological Surgery, Nagoya City University Graduate School of Medical Sciences, Nagoya, Aichi, Japan
| | - Satoru Takahashi
- Department of Experimental Pathology and Tumor Biology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Aichi, Japan
| | - Shuji Takiguchi
- Department of Gastroenterological Surgery, Nagoya City University Graduate School of Medical Sciences, Nagoya, Aichi, Japan
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Abstract
Pancreatic islet β cells secrete insulin in response to nutrient secretagogues, like glucose, dependent on calcium influx and nutrient metabolism. One of the most intriguing qualities of β cells is their ability to use metabolism to amplify the amount of secreted insulin independent of further alterations in intracellular calcium. Many years studying this amplifying process have shaped our current understanding of β cell stimulus-secretion coupling; yet, the exact mechanisms of amplification have been elusive. Recent studies utilizing metabolomics, computational modeling, and animal models have progressed our understanding of the metabolic amplifying pathway of insulin secretion from the β cell. New approaches will be discussed which offer in-roads to a more complete model of β cell function. The development of β cell therapeutics may be aided by such a model, facilitating the targeting of aspects of the metabolic amplifying pathway which are unique to the β cell.
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Affiliation(s)
- Michael A Kalwat
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX, United States.
| | - Melanie H Cobb
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX, United States
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Steensels S, Vancleef L, Depoortere I. The Sweetener-Sensing Mechanisms of the Ghrelin Cell. Nutrients 2016; 8:E795. [PMID: 27941594 DOI: 10.3390/nu8120795] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Revised: 11/21/2016] [Accepted: 11/28/2016] [Indexed: 12/12/2022] Open
Abstract
Carbohydrate administration decreases plasma levels of the ‘hunger hormone’ ghrelin. The ghrelin cell is co-localized with the sweet taste receptor subunit, TAS1R3, and the gustatory G-protein, gustducin, both involved in the sensing of sweeteners by entero-endocrine cells. This study investigated the role of gustducin-mediated sweet taste receptor signaling on ghrelin secretion in a gastric ghrelinoma cell line, tissue segments and mice. The monosaccharide d-glucose and low-intensity sweetener oligofructose (OFS) decreased (p < 0.001) ghrelin secretion while the high-intensity sweetener sucralose increased (p < 0.001) ghrelin secretion in vitro. These effects were not mediated via the sweet taste receptor or glucose transporters (the sodium-dependent glucose cotransporter SGLT-1 and GLUT2). The effect of these compounds was mimicked ex vivo in gastric and jejunal segments from both wild type (WT) and α-gustducin knockout (α-gust−/−) mice. In vivo, the sensing of d-glucose was polarized since intragastric but not intravenous administration of d-glucose decreased (p < 0.05) ghrelin levels in an α-gustducin independent manner which involved inhibition of duodenal ghrelin release. In contrast, neither OFS nor sucralose affected ghrelin secretion in vivo. In conclusion, α-gustducin-mediated sweet taste receptor signaling does not play a functional role in the sensing of carbohydrates, or low- or high-intensity sweeteners by the ghrelin cell.
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Elliott JA, Reynolds JV, le Roux CW, Docherty NG. Physiology, pathophysiology and therapeutic implications of enteroendocrine control of food intake. Expert Rev Endocrinol Metab 2016; 11:475-499. [PMID: 30058920 DOI: 10.1080/17446651.2016.1245140] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
With the increasing prevalence of obesity and its associated comorbidities, strides to improve treatment strategies have enhanced our understanding of the function of the gut in the regulation of food intake. The most successful intervention for obesity to date, bariatric surgery effectively manipulates enteroendocrine physiology to enhance satiety and reduce hunger. Areas covered: In the present article, we provide a detailed overview of the physiology of enteroendocrine control of food intake, and discuss its pathophysiologic correlates and therapeutic implications in both obesity and gastrointestinal disease. Expert commentary: Ongoing research in the field of nutrient sensing by L-cells, as well as understanding the role of the microbiome and bile acid signaling may facilitate the development of novel strategies to combat the rising population health threat associated with obesity. Further refinement of post-prandial satiety gut hormone based therapies, including the development of chimeric peptides exploiting the pleiotropic nature of the gut hormone response, and identification of novel methods of delivery may hold the key to optimization of therapeutic modulation of gut hormone physiology in obesity.
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Affiliation(s)
- Jessie A Elliott
- a Diabetes Complications Research Centre, Conway Institute of Biomedical and Biomolecular Research , University College Dublin , Dublin , Ireland
- b Department of Surgery, Trinity Centre for Health Sciences , Trinity College Dublin and St. James's Hospital , Dublin , Ireland
| | - John V Reynolds
- b Department of Surgery, Trinity Centre for Health Sciences , Trinity College Dublin and St. James's Hospital , Dublin , Ireland
| | - Carel W le Roux
- a Diabetes Complications Research Centre, Conway Institute of Biomedical and Biomolecular Research , University College Dublin , Dublin , Ireland
- c Gastrosurgical Laboratory, Sahlgrenska Academy , University of Gothenburg , Gothenburg , Sweden
| | - Neil G Docherty
- a Diabetes Complications Research Centre, Conway Institute of Biomedical and Biomolecular Research , University College Dublin , Dublin , Ireland
- c Gastrosurgical Laboratory, Sahlgrenska Academy , University of Gothenburg , Gothenburg , Sweden
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