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Kochem MC, Hanselman EC, Breslin PAS. Activation and inhibition of the sweet taste receptor TAS1R2-TAS1R3 differentially affect glucose tolerance in humans. PLoS One 2024; 19:e0298239. [PMID: 38691547 PMCID: PMC11062524 DOI: 10.1371/journal.pone.0298239] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Accepted: 01/19/2024] [Indexed: 05/03/2024] Open
Abstract
The sweet taste receptor, TAS1R2-TAS1R3, is expressed in taste bud cells, where it conveys sweetness, and also in intestinal enteroendocrine cells, where it may facilitate glucose absorption and assimilation. In the present study, our objective was to determine whether TAS1R2-TAS1R3 influences glucose metabolism bidirectionally via hyperactivation with 5 mM sucralose (n = 12) and inhibition with 2 mM sodium lactisole (n = 10) in mixture with 75 g glucose loads during oral glucose tolerance tests (OGTTs) in healthy humans. Plasma glucose, insulin, and glucagon were measured before, during, and after OGTTs up to 120 minutes post-prandially. We also assessed individual participants' sweet taste responses to sucralose and their sensitivities to lactisole sweetness inhibition. The addition of sucralose to glucose elevated plasma insulin responses to the OGTT (F(1, 11) = 4.55, p = 0.056). Sucralose sweetness ratings were correlated with early increases in plasma glucose (R2 = 0.41, p<0.05), as well as increases in plasma insulin (R2 = 0.38, p<0.05) when sucralose was added to the OGTT (15 minute AUC). Sensitivity to lactisole sweetness inhibition was correlated with decreased plasma glucose (R2 = 0.84, p<0.01) when lactisole was added to the OGTT over the whole test (120 minute AUC). In summary, stimulation and inhibition of the TAS1R2-TAS1R3 receptor demonstrates that TAS1R2-TAS1R3 helps regulate glucose metabolism in humans and may have translational implications for metabolic disease risk.
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Affiliation(s)
- Matthew C. Kochem
- Department of Nutritional Sciences, Rutgers University, New Brunswick, NJ, United States of America
| | - Emily C. Hanselman
- Department of Nutritional Sciences, Rutgers University, New Brunswick, NJ, United States of America
| | - Paul A. S. Breslin
- Department of Nutritional Sciences, Rutgers University, New Brunswick, NJ, United States of America
- Monell Chemical Senses Center, Philadelphia, PA, United States of America
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2
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Li Y, Cheng KC, Liu IM, Cheng JT. Identification of Andrographolide as an Agonist of Bile Acid TGR5 Receptor in a Cell Line to Demonstrate the Reduction in Hyperglycemia in Type-1 Diabetic Rats. Pharmaceuticals (Basel) 2023; 16:1417. [PMID: 37895888 PMCID: PMC10610544 DOI: 10.3390/ph16101417] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 10/01/2023] [Accepted: 10/02/2023] [Indexed: 10/29/2023] Open
Abstract
Andrographolide (ADG) is contained in bitter plants, and its effects are widely thought to be associated with taste receptors. The current study used animal studies and cell lines to investigate the role of ADG in diabetic models. The Takeda G-protein-coupled receptor (TGR5) was directly influenced by ADG, and this boosted GLP-1 synthesis in CHO-K1 cells transfected with the TGR5 gene. However, this was not seen in TGR5-mutant cells. The human intestinal L-cell line NCI-H716 showed an increase in GLP-1 production in response to ADG. In NCI-H716 cells, the TGR5 inhibitor triamterene reduced the effects of ADG, including the rise in TGR5 mRNA levels that ADG caused. Additionally, as with the antihyperglycemic impact in type-1 diabetic rats, the increase in plasma-active GLP-1 level caused by ADG was enhanced by a DPP-4 inhibitor. The recovery of the hypoglycemic effect in diabetic rats and the increase in plasma GLP-1 caused by ADG were both suppressed by TGR5 blockers. As a result, after activating TGR5, ADG may boost GLP-1 synthesis in diabetic rats, enhancing glucose homeostasis. In Min-6 cells, a pancreatic cell line grown in culture, ADG-induced insulin secretion was also examined. Blocking GLP-1 receptors had little impact, suggesting that ADG directly affects TGR5 activity in Min-6 cells. A TGR5 mRNA level experiment in Min-6 cells further confirmed that TGR5 is activated by ADG. The current study revealed a novel finding suggesting that ADG may activate TGR5 in diabetic rats in a way that results in enhanced insulin and GLP-1 production, which may be helpful for future research and therapies.
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Affiliation(s)
- Yingxiao Li
- Department of Nursing, Tzu Chi University of Science and Technology, Hualien 970302, Taiwan;
| | - Kai-Chun Cheng
- Department of Pharmacy, College of Pharmacy, Tajen University, Pingtung 90741, Taiwan; (K.-C.C.); (I.-M.L.)
| | - I-Min Liu
- Department of Pharmacy, College of Pharmacy, Tajen University, Pingtung 90741, Taiwan; (K.-C.C.); (I.-M.L.)
| | - Juei-Tang Cheng
- Institute of Medical Sciences, Chang Jung Christian University, Tainan City 71101, Taiwan
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Wang Y, Geng R, Zhao Y, Fang J, Li M, Kang SG, Huang K, Tong T. The gut odorant receptor and taste receptor make sense of dietary components: A focus on gut hormone secretion. Crit Rev Food Sci Nutr 2023; 64:6975-6989. [PMID: 36785901 DOI: 10.1080/10408398.2023.2177610] [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] [Indexed: 02/15/2023]
Abstract
Odorant receptors (ORs) and taste receptors (TRs) are expressed primarily in the nose and tongue in which they transduce electrical signals to the brain. Advances in deciphering the dietary component-sensing mechanisms in the nose and tongue prompted research on the role of gut chemosensory cells. Acting as the pivotal interface between the body and dietary cues, gut cells "smell" and "taste" dietary components and metabolites by taking advantage of chemoreceptors-ORs and TRs, to maintain physiological homeostasis. Here, we reviewed this novel field, highlighting the latest discoveries pertinent to gut ORs and TRs responding to dietary components, their impacts on gut hormone secretion, and the mechanisms involved. Recent studies indicate that gut cells sense dietary components including fatty acid, carbohydrate, and phytochemical by activating relevant ORs, thereby modulating GLP-1, PYY, CCK, and 5-HT secretion. Similarly, gut sweet, umami, and bitter receptors can regulate the gut hormone secretion and maintain homeostasis in response to dietary components. A deeper understanding of the favorable influence of dietary components on gut hormone secretion via gut ORs and TRs, coupled with the facts that gut hormones are involved in diverse physiological or pathophysiological phenomena, may ultimately lead to a promising treatment for various human diseases.
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Affiliation(s)
- Yanan Wang
- Key Laboratory of Precision Nutrition and Food Quality, Key Laboratory of Functional Dairy, Ministry of Education; College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, PR China
| | - Ruixuan Geng
- Key Laboratory of Precision Nutrition and Food Quality, Key Laboratory of Functional Dairy, Ministry of Education; College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, PR China
| | - Yuhan Zhao
- Key Laboratory of Precision Nutrition and Food Quality, Key Laboratory of Functional Dairy, Ministry of Education; College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, PR China
| | - Jingjing Fang
- Key Laboratory of Precision Nutrition and Food Quality, Key Laboratory of Functional Dairy, Ministry of Education; College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, PR China
| | - Mengjie Li
- Key Laboratory of Precision Nutrition and Food Quality, Key Laboratory of Functional Dairy, Ministry of Education; College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, PR China
| | - Seong-Gook Kang
- Department of Food Engineering, Mokpo National University, Muangun, Korea
| | - Kunlun Huang
- Key Laboratory of Precision Nutrition and Food Quality, Key Laboratory of Functional Dairy, Ministry of Education; College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, PR China
- Key Laboratory of Safety Assessment of Genetically Modified Organism (Food Safety), Ministry of Agriculture, Beijing, PR China
- Beijing Laboratory for Food Quality and Safety, Beijing, PR China
| | - Tao Tong
- Key Laboratory of Precision Nutrition and Food Quality, Key Laboratory of Functional Dairy, Ministry of Education; College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, PR China
- Key Laboratory of Safety Assessment of Genetically Modified Organism (Food Safety), Ministry of Agriculture, Beijing, PR China
- Beijing Laboratory for Food Quality and Safety, Beijing, PR China
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4
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Type II taste cells participate in mucosal immune surveillance. PLoS Biol 2023; 21:e3001647. [PMID: 36634039 PMCID: PMC9836272 DOI: 10.1371/journal.pbio.3001647] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Accepted: 12/10/2022] [Indexed: 01/13/2023] Open
Abstract
The oral microbiome is second only to its intestinal counterpart in diversity and abundance, but its effects on taste cells remains largely unexplored. Using single-cell RNASeq, we found that mouse taste cells, in particular, sweet and umami receptor cells that express taste 1 receptor member 3 (Tas1r3), have a gene expression signature reminiscent of Microfold (M) cells, a central player in immune surveillance in the mucosa-associated lymphoid tissue (MALT) such as those in the Peyer's patch and tonsils. Administration of tumor necrosis factor ligand superfamily member 11 (TNFSF11; also known as RANKL), a growth factor required for differentiation of M cells, dramatically increased M cell proliferation and marker gene expression in the taste papillae and in cultured taste organoids from wild-type (WT) mice. Taste papillae and organoids from knockout mice lacking Spib (SpibKO), a RANKL-regulated transcription factor required for M cell development and regeneration on the other hand, failed to respond to RANKL. Taste papillae from SpibKO mice also showed reduced expression of NF-κB signaling pathway components and proinflammatory cytokines and attracted fewer immune cells. However, lipopolysaccharide-induced expression of cytokines was strongly up-regulated in SpibKO mice compared to their WT counterparts. Like M cells, taste cells from WT but not SpibKO mice readily took up fluorescently labeled microbeads, a proxy for microbial transcytosis. The proportion of taste cell subtypes are unaltered in SpibKO mice; however, they displayed increased attraction to sweet and umami taste stimuli. We propose that taste cells are involved in immune surveillance and may tune their taste responses to microbial signaling and infection.
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Ki SY, Jeong YT. Taste Receptors beyond Taste Buds. Int J Mol Sci 2022; 23:ijms23179677. [PMID: 36077074 PMCID: PMC9455917 DOI: 10.3390/ijms23179677] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2022] [Revised: 08/18/2022] [Accepted: 08/24/2022] [Indexed: 11/16/2022] Open
Abstract
Taste receptors are responsible for detecting their ligands not only in taste receptor cells (TRCs) but also in non-gustatory organs. For several decades, many research groups have accumulated evidence for such “ectopic” expression of taste receptors. More recently, some of the physiologic functions (apart from taste) of these ectopic taste receptors have been identified. Here, we summarize our current understanding of these ectopic taste receptors across multiple organs. With a particular focus on the specialized epithelial cells called tuft cells, which are now considered siblings of type II TRCs, we divide the ectopic expression of taste receptors into two categories: taste receptors in TRC-like cells outside taste buds and taste receptors with surprising ectopic expression in completely different cell types.
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Affiliation(s)
- Su Young Ki
- Department of Pharmacology, Korea University College of Medicine, Seoul 02841, Korea
| | - Yong Taek Jeong
- Department of Pharmacology, Korea University College of Medicine, Seoul 02841, Korea
- BK21 Graduate Program, Department of Biomedical Sciences, Korea University College of Medicine, Seoul 02841, Korea
- Correspondence: ; Tel.: +82-2-2286-1295
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Ercin M, Gezginci-Oktayoglu S, Bolkent S. Exendin-4 inhibits small intestinal glucose sensing and absorption through repression of T1R2/T1R3 sweet taste receptor signalling in streptozotocin diabetic mice. Transl Res 2022; 246:87-101. [PMID: 35385790 DOI: 10.1016/j.trsl.2022.03.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 02/14/2022] [Accepted: 03/29/2022] [Indexed: 11/29/2022]
Abstract
The small intestine, which is the area where sugars are absorbed, should be considered in the approaches developed for the treatment of diabetes. However, studies on small intestine damage in diabetic individuals, and the effects of current treatments on the small intestine are very limited. This is the first study to investigate the effects of exendin-4, a GLP-1 receptor agonist, on small intestine injury in diabetic mice. BALB/c male mice were divided into 4 groups for this study. The first group was given citrate buffer, the second group was given exendin-4, the third group was given streptozotocin (STZ), and the fourth group was given both exendin-4, and STZ. As the results, we determined a decrease in the edema and deterioration in the integrity of the villi, disruption in continuity of the brush border, fibrosis and enterocyte apoptosis, while the TNFα level and crypt cell proliferation were increased in the small intestinal tissue of exendin-4 treated STZ diabetic mice. Furthermore, the levels of duodenal tissue glucose, SGLT1, and GLUT2 were decreased, whereas there was an increase in GIP level in diabetic mice administered with exendin-4. Moreover, we determined that the sweet taste receptors T1R2/T1R3, downstream molecules PLCβ2, α-gustducin and associated secondary messengers IP3, cAMP, which were increased in the duodenal tissue of STZ-diabetic mice, decreased with exendin-4 administration. These findings were evaluated as that exendin-4 reduces glucose absorption by suppressing the T1R2/T1R3 sweet taste signal perception pathway in duodenum of STZ diabetic mice.
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Affiliation(s)
- Merve Ercin
- Faculty of Science, Biology Department, Molecular Biology Section, Istanbul University, Istanbul, Turkey; Biology Section, Molecular Biology Program, Istanbul University, Institute of Science, Istanbul, Turkey.
| | - Selda Gezginci-Oktayoglu
- Faculty of Science, Biology Department, Molecular Biology Section, Istanbul University, Istanbul, Turkey
| | - Sehnaz Bolkent
- Faculty of Science, Biology Department, Molecular Biology Section, Istanbul University, Istanbul, Turkey
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7
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Kondo T, Uebanso T, Arao N, Shimohata T, Mawatari K, Takahashi A. Effect of T1R3 Taste Receptor Gene Deletion on Dextran Sulfate Sodium-Induced Colitis in Mice. J Nutr Sci Vitaminol (Tokyo) 2022; 68:204-212. [PMID: 35768251 DOI: 10.3177/jnsv.68.204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Taste receptor type 1 member 3 (T1R3) recognize umami or sweet tastes and also contributes type 2 immunity and autophagy in small intestine and muscle cells, respectively. Since imbalance of type 1 and type 2 immunity and autophagy affect intestinal bowel disease (IBD), we hypothesized that T1R3 have a potential role in the incidence and progression of colitis. In the present study, we investigated whether genetic deletion of T1R3 impacted aggravation of DSS-induced colitis in mice. We found that T1R3-KO mice showed reduction in colon damage, including reduced inflammation and colon shrinking relative to those of WT mice following DSS treatment. mRNA expression of tight junction components, particularly claudin1 was significantly lower in T1R3-KO mice with trend to lower inflammation related gene mRNA expression in colon. Other parameters, such as response to microbial stimuli in splenic lymphocytes and peritoneal macrophages, gut microbiota composition, and expression of autophagy-related proteins, were similar between WT and KO mice. Together, these results indicated that deletion of T1R3 has a minor role in intestinal inflammation induced by DSS-induced acute colitis in mice.
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Affiliation(s)
- Tsubasa Kondo
- Department of Preventive Environment and Nutrition, Institute of Biomedical Sciences, Tokushima University Graduate School
| | - Takashi Uebanso
- Department of Preventive Environment and Nutrition, Institute of Biomedical Sciences, Tokushima University Graduate School
| | - Natsuki Arao
- Department of Preventive Environment and Nutrition, Institute of Biomedical Sciences, Tokushima University Graduate School
| | - Takaaki Shimohata
- Department of Preventive Environment and Nutrition, Institute of Biomedical Sciences, Tokushima University Graduate School.,Faculty of Marine Biosciences, Fukui Prefectural University
| | - Kazuaki Mawatari
- Department of Preventive Environment and Nutrition, Institute of Biomedical Sciences, Tokushima University Graduate School
| | - Akira Takahashi
- Department of Preventive Environment and Nutrition, Institute of Biomedical Sciences, Tokushima University Graduate School
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8
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Serrano J, Yi F, Smith J, Pratley RE, Kyriazis GA. The Ile191Val Variant of the TAS1R2 Subunit of Sweet Taste Receptors Is Associated With Reduced HbA1c in a Human Cohort With Variable Levels of Glucose Homeostasis. Front Nutr 2022; 9:896205. [PMID: 35662939 PMCID: PMC9160323 DOI: 10.3389/fnut.2022.896205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 05/05/2022] [Indexed: 11/13/2022] Open
Abstract
The Ile191Val variant of the TAS1R2 gene of sweet taste receptors causes a partial loss-of-function and is associated with reduced glucose excursions in a healthy lean cohort. However, it is unclear whether this polymorphism contributes to the regulation of glucose homeostasis in metabolically unhealthy individuals. Thus, we used participants with variable glycemic profiles and obesity to assess the effects of the TAS1R2-Ile191Val variant. We found that the Val minor allele carriers had lower HbA1c at all levels of fasting glucose and glucose tolerance. These effects were not due to differences in beta-cell function or insulin sensitivity assessed with a frequently sampled intravenous glucose tolerance test. This study extends our previous findings and provides further evidence that sweet taste receptor function may contribute to glucose regulation in humans.
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Affiliation(s)
- Joan Serrano
- Department of Biological Chemistry and Pharmacology, College of Medicine, The Ohio State University, Columbus, OH, United States
| | - Fanchao Yi
- AdventHealth Translational Research Institute, Orlando, FL, United States
| | - Joshua Smith
- AdventHealth Translational Research Institute, Orlando, FL, United States
| | - Richard E. Pratley
- AdventHealth Translational Research Institute, Orlando, FL, United States
| | - George A. Kyriazis
- Department of Biological Chemistry and Pharmacology, College of Medicine, The Ohio State University, Columbus, OH, United States
- *Correspondence: George A. Kyriazis
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9
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Serrano J, Meshram NN, Soundarapandian MM, Smith KR, Mason C, Brown IS, Tyrberg B, Kyriazis GA. Saccharin Stimulates Insulin Secretion Dependent on Sweet Taste Receptor-Induced Activation of PLC Signaling Axis. Biomedicines 2022; 10:biomedicines10010120. [PMID: 35052799 PMCID: PMC8773316 DOI: 10.3390/biomedicines10010120] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 12/27/2021] [Accepted: 01/04/2022] [Indexed: 02/05/2023] Open
Abstract
Background: Saccharin is a common artificial sweetener and a bona fide ligand for sweet taste receptors (STR). STR can regulate insulin secretion in beta cells, so we investigated whether saccharin can stimulate insulin secretion dependent on STR and the activation of phospholipase C (PLC) signaling. Methods: We performed in vivo and in vitro approaches in mice and cells with loss-of-function of STR signaling and specifically assessed the involvement of a PLC signaling cascade using real-time biosensors and calcium imaging. Results: We found that the ingestion of a physiological amount of saccharin can potentiate insulin secretion dependent on STR. Similar to natural sweeteners, saccharin triggers the activation of the PLC signaling cascade, leading to calcium influx and the vesicular exocytosis of insulin. The effects of saccharin also partially require transient receptor potential cation channel M5 (TRPM5) activity. Conclusions: Saccharin ingestion may transiently potentiate insulin secretion through the activation of the canonical STR signaling pathway. These physiological effects provide a framework for understanding the potential health impact of saccharin use and the contribution of STR in peripheral tissues.
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Affiliation(s)
- Joan Serrano
- Department of Biological Chemistry and Pharmacology, College of Medicine, The Ohio State University, Columbus, OH 43210, USA; (J.S.); (N.N.M.); (C.M.); (I.S.B.)
| | - Nishita N. Meshram
- Department of Biological Chemistry and Pharmacology, College of Medicine, The Ohio State University, Columbus, OH 43210, USA; (J.S.); (N.N.M.); (C.M.); (I.S.B.)
| | | | - Kathleen R. Smith
- Sanford Burnham Prebys Medical Discovery Institute, Lake Nona, FL 32827, USA; (M.M.S.); (K.R.S.)
| | - Carter Mason
- Department of Biological Chemistry and Pharmacology, College of Medicine, The Ohio State University, Columbus, OH 43210, USA; (J.S.); (N.N.M.); (C.M.); (I.S.B.)
| | - Ian S. Brown
- Department of Biological Chemistry and Pharmacology, College of Medicine, The Ohio State University, Columbus, OH 43210, USA; (J.S.); (N.N.M.); (C.M.); (I.S.B.)
| | - Björn Tyrberg
- Department of Physiology, Sahlgrenska Academy, University of Gothenburg, 405 30 Gothenburg, Sweden;
| | - George A. Kyriazis
- Department of Biological Chemistry and Pharmacology, College of Medicine, The Ohio State University, Columbus, OH 43210, USA; (J.S.); (N.N.M.); (C.M.); (I.S.B.)
- Correspondence: or
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11
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Jensterle M, DeVries JH, Battelino T, Battelino S, Yildiz B, Janez A. Glucagon-like peptide-1, a matter of taste? Rev Endocr Metab Disord 2021; 22:763-775. [PMID: 33123893 DOI: 10.1007/s11154-020-09609-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 10/26/2020] [Indexed: 01/22/2023]
Abstract
Understanding of gustatory coding helps to predict, and perhaps even modulate the ingestive decision circuitry, especially when eating behaviour becomes dysfunctional. Preclinical research demonstrated that glucagon like peptide 1 (GLP-1) is locally synthesized in taste bud cells in the tongue and that GLP-1 receptor exists on the gustatory nerves in close proximity to GLP-1 containing taste bud cells. In humans, the tongue has not yet been addressed as clinically relevant target for GLP-1 based therapies. The primary aim of the current review was to elaborate on the role of GLP- 1 in mammalian gustatory system, in particular in the perception of sweet. Secondly, we aimed to explore what modulates gustatory coding and whether the GLP-1 based therapies might be involved in regulation of taste perception. We performed a series of PubMed, Medline and Embase databases systemic searches. The Population-Intervention-Comparison-Outcome (PICO) framework was used to identify interventional studies. Based on the available data, GLP-1 is specifically involved in the perception of sweet. Aging, diabetes and obesity are characterized by diminished taste and sweet perception. Calorie restriction and bariatric surgery are associated with a diminished appreciation of sweet food. GLP-1 receptor agonists (RAs) modulate food preference, yet its modulatory potential in gustatory coding is currently unknown. Future studies should explore whether GLP-1 RAs modulate taste perception to the extent that changes of food preference and consumption ensue.
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Affiliation(s)
- Mojca Jensterle
- Division of Internal Medicine, Department of Endocrinology, Diabetes and Metabolic Diseases, University Medical Centre Ljubljana, Zaloška cesta, 7, 1000, Ljubljana, Slovenia
- Department of Internal Medicine, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia, Zaloška cesta 7, 1000, Ljubljana, Slovenia
| | - J Hans DeVries
- Department of Endocrinology and Metabolism, Amsterdam University Medical Center, University of Amsterdam, Meibergdreef 9, 1105, AZ, Amsterdam, The Netherlands
| | - Tadej Battelino
- Department of Endocrinology, Diabetes and Metabolism, University Children's Hospital, University Medical Centre Ljubljana, Bohoričeva 20, SI-1000, Ljubljana, Slovenia
- Department of Pediatrics, Faculty of Medicine, University of Ljubljana, Bohoričeva 20, SI-1000, Ljubljana, Slovenia
| | - Saba Battelino
- Department of Otorhinolaryngology and Cervicofacial Surgery, University Medical Centre Ljubljana, Zaloska cesta 2, 1000, Ljubljana, Slovenia
- Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Bulent Yildiz
- Department of Internal Medicine, Division of Endocrinology and Metabolism, Hacettepe University School of Medicine, Hacettepe, 06100, Ankara, Turkey
| | - Andrej Janez
- Division of Internal Medicine, Department of Endocrinology, Diabetes and Metabolic Diseases, University Medical Centre Ljubljana, Zaloška cesta, 7, 1000, Ljubljana, Slovenia.
- Department of Internal Medicine, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia, Zaloška cesta 7, 1000, Ljubljana, Slovenia.
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12
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Burman A, Kaji I. Luminal Chemosensory Cells in the Small Intestine. Nutrients 2021; 13:nu13113712. [PMID: 34835968 PMCID: PMC8620795 DOI: 10.3390/nu13113712] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2021] [Revised: 10/19/2021] [Accepted: 10/20/2021] [Indexed: 12/23/2022] Open
Abstract
In addition to the small intestine's well-known function of nutrient absorption, the small intestine also plays a major role in nutrient sensing. Similar to taste sensors seen on the tongue, GPCR-coupled nutrient sensors are expressed throughout the intestinal epithelium and respond to nutrients found in the lumen. These taste receptors respond to specific ligands, such as digested carbohydrates, fats, and proteins. The activation of nutrient sensors in the intestine allows for the induction of signaling pathways needed for the digestive system to process an influx of nutrients. Such processes include those related to glucose homeostasis and satiety. Defects in intestinal nutrient sensing have been linked to a variety of metabolic disorders, such as type 2 diabetes and obesity. Here, we review recent updates in the mechanisms related to intestinal nutrient sensors, particularly in enteroendocrine cells, and their pathological roles in disease. Additionally, we highlight the emerging nutrient sensing role of tuft cells and recent work using enteroids as a sensory organ model.
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Affiliation(s)
- Andreanna Burman
- Cell and Developmental Biology and Epithelial Biology Center, Vanderbilt University School of Medicine, Nashville, TN 37232, USA;
| | - Izumi Kaji
- Epithelial Biology Center and Section of Surgical Sciences, Vanderbilt University Medical Center, Nashville, TN 37232, USA
- Correspondence:
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13
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Le Gléau L, Rouault C, Osinski C, Prifti E, Soula HA, Debédat J, Busieau P, Amouyal C, Clément K, Andreelli F, Ribeiro A, Serradas P. Intestinal alteration of α-gustducin and sweet taste signaling pathway in metabolic diseases is partly rescued after weight loss and diabetes remission. Am J Physiol Endocrinol Metab 2021; 321:E417-E432. [PMID: 34338041 DOI: 10.1152/ajpendo.00071.2021] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Accepted: 07/20/2021] [Indexed: 12/15/2022]
Abstract
Carbohydrates and sweeteners are detected by the sweet taste receptor in enteroendocrine cells (EECs). This receptor is coupled to the gustducin G-protein, which α-subunit is encoded by GNAT3 gene. In intestine, the activation of sweet taste receptor triggers a signaling pathway leading to GLP-1 secretion, an incretin hormone. In metabolic diseases, GLP-1 concentration and incretin effect are reduced while partly restored after Roux-en-Y gastric bypass (RYGB). We wondered if the decreased GLP-1 secretion in metabolic diseases is caused by an intestinal defect in sweet taste transduction pathway. In our RNA-sequencing of EECs, GNAT3 expression is decreased in patients with obesity and type 2 diabetes compared with normoglycemic obese patients. This prompted us to explore sweet taste signaling pathway in mice with metabolic deteriorations. During obesity onset in mice, Gnat3 expression was downregulated in EECs. After metabolic improvement with enterogastro anastomosis surgery in mice (a surrogate of the RYGB in humans), the expression of Gnat3 increased in the new alimentary tract and glucose-induced GLP-1 secretion was improved. To evaluate if high-fat diet-induced dysbiotic intestinal microbiota could explain the changes in the expression of sweet taste α-subunit G-protein, we performed a fecal microbiota transfer in mice. However, we could not conclude if dysbiotic microbiota impacted or not intestinal Gnat3 expression. Our data highlight that metabolic disorders were associated with altered gene expression of sweet taste signaling in intestine. This could contribute to impaired GLP-1 secretion that is partly rescued after metabolic improvement.NEW & NOTEWORTHY Our data highlighted 1) the sweet taste transduction pathway in EECs plays pivotal role for glucose homeostasis at least at gene expression level; 2) metabolic disorders lead to altered gene expression of sweet taste signaling pathway in intestine contributing to impaired GLP-1 secretion; and 3) after surgical intestinal modifications, increased expression of GNAT3, encoding α-gustducin contributed to metabolic improvement.
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Affiliation(s)
- Léa Le Gléau
- Sorbonne Université, INSERM, Nutrition and Obesities: Systemic Approaches (NutriOmics), Paris, France
| | - Christine Rouault
- Sorbonne Université, INSERM, Nutrition and Obesities: Systemic Approaches (NutriOmics), Paris, France
| | - Céline Osinski
- Sorbonne Université, INSERM, Nutrition and Obesities: Systemic Approaches (NutriOmics), Paris, France
| | - Edi Prifti
- Sorbonne Université, INSERM, Nutrition and Obesities: Systemic Approaches (NutriOmics), Paris, France
- IRD, Sorbonne University, UMMISCO, Bondy, France
| | - Hédi Antoine Soula
- Sorbonne Université, INSERM, Nutrition and Obesities: Systemic Approaches (NutriOmics), Paris, France
| | - Jean Debédat
- Sorbonne Université, INSERM, Nutrition and Obesities: Systemic Approaches (NutriOmics), Paris, France
| | - Pauline Busieau
- Sorbonne Université, INSERM, Nutrition and Obesities: Systemic Approaches (NutriOmics), Paris, France
| | - Chloé Amouyal
- Sorbonne Université, INSERM, Nutrition and Obesities: Systemic Approaches (NutriOmics), Paris, France
- Assistance Publique/Hôpitaux de Paris, APHP, Nutrition Department, Pitié-Salpêtrière Hospital, Paris, France
- Assistance Publique-Hôpitaux de Paris, APHP, Diabetology-Metabolisms Department, Pitié-Salpêtrière Hospital, Paris, France
| | - Karine Clément
- Sorbonne Université, INSERM, Nutrition and Obesities: Systemic Approaches (NutriOmics), Paris, France
- Assistance Publique/Hôpitaux de Paris, APHP, Nutrition Department, Pitié-Salpêtrière Hospital, Paris, France
| | - Fabrizio Andreelli
- Sorbonne Université, INSERM, Nutrition and Obesities: Systemic Approaches (NutriOmics), Paris, France
- Assistance Publique/Hôpitaux de Paris, APHP, Nutrition Department, Pitié-Salpêtrière Hospital, Paris, France
- Assistance Publique-Hôpitaux de Paris, APHP, Diabetology-Metabolisms Department, Pitié-Salpêtrière Hospital, Paris, France
| | - Agnès Ribeiro
- Sorbonne Université, INSERM, Nutrition and Obesities: Systemic Approaches (NutriOmics), Paris, France
| | - Patricia Serradas
- Sorbonne Université, INSERM, Nutrition and Obesities: Systemic Approaches (NutriOmics), Paris, France
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14
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Abstract
Glucagon-like peptide-1 (GLP-1) is an enterohormone with a key role in several processes controlling body homeostasis, including glucose homeostasis and food intake regulation. It is secreted by the intestinal cells in response to nutrients, such as glucose, fat and amino acids. In the present review, we analyse the effect of protein on GLP-1 secretion and clearance. We review the literature on the GLP-1 secretory effects of protein and protein hydrolysates, and the mechanisms through which they exert these effects. We also review the studies on protein from different sources that has inhibitory effects on dipeptidyl peptidase-4 (DPP4), the enzyme responsible for GLP-1 inactivation, with particular emphasis on specific sources and treatments, and the gaps there still are in knowledge. There is evidence that the protein source and the hydrolytic processing applied to them can influence the effects on GLP-1 signalling. The gastrointestinal digestion of proteins, for example, significantly changes their effectiveness at modulating this enterohormone secretion in both in vivo and in vitro studies. Nevertheless, little information is available regarding human studies and more research is required to understand their potential as regulators of glucose homeostasis.
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15
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Nunez-Salces M, Li H, Feinle-Bisset C, Young RL, Page AJ. Nutrient-sensing components of the mouse stomach and the gastric ghrelin cell. Neurogastroenterol Motil 2020; 32:e13944. [PMID: 32666613 DOI: 10.1111/nmo.13944] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Revised: 04/22/2020] [Accepted: 06/22/2020] [Indexed: 12/14/2022]
Abstract
BACKGROUND The ability of the gut to detect nutrients is critical to the regulation of gut hormone secretion, food intake, and postprandial blood glucose control. Ingested nutrients are detected by specific gut chemosensors. However, knowledge of these chemosensors has primarily been derived from the intestine, while available information on gastric chemosensors is limited. This study aimed to investigate the nutrient-sensing repertoire of the mouse stomach with particular emphasis on ghrelin cells. METHODS Quantitative RT-PCR was used to determine mRNA levels of nutrient chemosensors (protein: G protein-coupled receptor 93 [GPR93], calcium-sensing receptor [CaSR], metabotropic glutamate receptor type 4 [mGluR4]; fatty acids: CD36, FFAR2&4; sweet/umami taste: T1R3), taste transduction components (TRPM5, GNAT2&3), and ghrelin and ghrelin-processing enzymes (PC1/3, ghrelin O-acyltransferase [GOAT]) in the gastric corpus and antrum of adult male C57BL/6 mice. Immunohistochemistry was performed to assess protein expression of chemosensors (GPR93, T1R3, CD36, and FFAR4) and their co-localization with ghrelin. KEY RESULTS Most nutrient chemosensors had higher mRNA levels in the antrum compared to the corpus, except for CD36, GNAT2, ghrelin, and GOAT. Similar regional distribution was observed at the protein level. At least 60% of ghrelin-positive cells expressed T1R3 and FFAR4, and over 80% expressed GPR93 and CD36. CONCLUSIONS AND INFERENCES The cellular mechanisms for the detection of nutrients are expressed in a region-specific manner in the mouse stomach and gastric ghrelin cells. These gastric nutrient chemosensors may play a role modulating gastrointestinal responses, such as the inhibition of ghrelin secretion following food intake.
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Affiliation(s)
- Maria Nunez-Salces
- Vagal Afferent Research Group, Adelaide Medical School, The University of Adelaide, Adelaide, SA, Australia.,Centre of Research Excellence in Translating Nutritional Science to Good Health, Adelaide Medical School, The University of Adelaide, Adelaide, SA, Australia.,Nutrition, Diabetes & Gut Health, Lifelong Health Theme, South Australian Health & Medical Research Institute (SAHMRI), Adelaide, SA, Australia
| | - Hui Li
- Vagal Afferent Research Group, Adelaide Medical School, The University of Adelaide, Adelaide, SA, Australia.,Centre of Research Excellence in Translating Nutritional Science to Good Health, Adelaide Medical School, The University of Adelaide, Adelaide, SA, Australia.,Nutrition, Diabetes & Gut Health, Lifelong Health Theme, South Australian Health & Medical Research Institute (SAHMRI), Adelaide, SA, Australia
| | - Christine Feinle-Bisset
- Centre of Research Excellence in Translating Nutritional Science to Good Health, Adelaide Medical School, The University of Adelaide, Adelaide, SA, Australia
| | - Richard L Young
- Centre of Research Excellence in Translating Nutritional Science to Good Health, Adelaide Medical School, The University of Adelaide, Adelaide, SA, Australia.,Nutrition, Diabetes & Gut Health, Lifelong Health Theme, South Australian Health & Medical Research Institute (SAHMRI), Adelaide, SA, Australia.,Intestinal Nutrient Sensing Group, Adelaide Medical School, The University of Adelaide, Adelaide, SA, Australia
| | - Amanda J Page
- Vagal Afferent Research Group, Adelaide Medical School, The University of Adelaide, Adelaide, SA, Australia.,Centre of Research Excellence in Translating Nutritional Science to Good Health, Adelaide Medical School, The University of Adelaide, Adelaide, SA, Australia.,Nutrition, Diabetes & Gut Health, Lifelong Health Theme, South Australian Health & Medical Research Institute (SAHMRI), Adelaide, SA, Australia
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16
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Abstract
Understanding of gustatory coding helps to predict, and perhaps even modulate the ingestive decision circuitry, especially when eating behaviour becomes dysfunctional. Preclinical research demonstrated that glucagon like peptide 1 (GLP-1) is locally synthesized in taste bud cells in the tongue and that GLP-1 receptor exists on the gustatory nerves in close proximity to GLP-1 containing taste bud cells. In humans, the tongue has not yet been addressed as clinically relevant target for GLP-1 based therapies. The primary aim of the current review was to elaborate on the role of GLP- 1 in mammalian gustatory system, in particular in the perception of sweet. Secondly, we aimed to explore what modulates gustatory coding and whether the GLP-1 based therapies might be involved in regulation of taste perception. We performed a series of PubMed, Medline and Embase databases systemic searches. The Population-Intervention-Comparison-Outcome (PICO) framework was used to identify interventional studies. Based on the available data, GLP-1 is specifically involved in the perception of sweet. Aging, diabetes and obesity are characterized by diminished taste and sweet perception. Calorie restriction and bariatric surgery are associated with a diminished appreciation of sweet food. GLP-1 receptor agonists (RAs) modulate food preference, yet its modulatory potential in gustatory coding is currently unknown. Future studies should explore whether GLP-1 RAs modulate taste perception to the extent that changes of food preference and consumption ensue.
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17
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Andres-Hernando A, Kuwabara M, Orlicky DJ, Vandenbeuch A, Cicerchi C, Kinnamon SC, Finger TE, Johnson RJ, Lanaspa MA. Sugar causes obesity and metabolic syndrome in mice independently of sweet taste. Am J Physiol Endocrinol Metab 2020; 319:E276-E290. [PMID: 32574112 PMCID: PMC7473911 DOI: 10.1152/ajpendo.00529.2019] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Intake of sugars, especially the fructose component, is strongly associated with the development of obesity and metabolic syndrome, but the relative role of taste versus metabolism in driving preference, intake, and metabolic outcome is not fully understood. We aimed to evaluate the preference for sweet substances and the tendency to develop metabolic syndrome in response to these sugars in mice lacking functional taste signaling [P2X2 (P2X purinoreceptor 2)/P2X3 (P2X purinoreceptor 3) double knockout mice (DKO)] and mice unable to metabolize fructose (fructokinase knockout mice). Of interest, our data indicate that despite their inability to taste sweetness, P2X2/3 DKO mice still prefer caloric sugars (including fructose and glucose) to water in long-term testing, although with diminished preference compared with control mice. Despite reduced intake of caloric sugars by P2X2/3 DKO animals, the DKO mice still show increased levels of the sugar-dependent hormone FGF21 (fibroblast growth factor 21) in plasma and liver. Despite lower sugar intake, taste-blind mice develop severe features of metabolic syndrome due to reduced sensitivity to leptin, reduced ability to mobilize and oxidize fats, and increased hepatic de novo lipogenesis. In contrast to P2X2/3 DKO and wild-type mice, fructokinase knockout mice, which cannot metabolize fructose and are protected against fructose-induced metabolic syndrome, demonstrate reduced preference and intake for all fructose-containing sugars tested but not for glucose or artificial sweeteners. Based on these observations, we conclude that sugar can induce metabolic syndrome in mice independently of its sweet properties. Furthermore, our data demonstrate that the metabolism of fructose is necessary for sugar to drive intake and preference in mice.
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Affiliation(s)
- Ana Andres-Hernando
- Division of Renal Diseases and Hypertension, University of Colorado School of Medicine, University of Colorado, Aurora, Colorado
| | - Masanari Kuwabara
- Division of Renal Diseases and Hypertension, University of Colorado School of Medicine, University of Colorado, Aurora, Colorado
| | - David J Orlicky
- Department of Pathology, University of Colorado School of Medicine, University of Colorado, Aurora, Colorado
| | - Aurelie Vandenbeuch
- Department of Otolaryngology, University of Colorado School of Medicine, University of Colorado, Aurora, Colorado
- Rocky Mountain Taste & Smell Center, University of Colorado School of Medicine, University of Colorado, Aurora, Colorado
| | - Christina Cicerchi
- Division of Renal Diseases and Hypertension, University of Colorado School of Medicine, University of Colorado, Aurora, Colorado
| | - Sue C Kinnamon
- Department of Otolaryngology, University of Colorado School of Medicine, University of Colorado, Aurora, Colorado
- Rocky Mountain Taste & Smell Center, University of Colorado School of Medicine, University of Colorado, Aurora, Colorado
| | - Thomas E Finger
- Rocky Mountain Taste & Smell Center, University of Colorado School of Medicine, University of Colorado, Aurora, Colorado
- Department of Cell and Developmental Biology, University of Colorado School of Medicine, University of Colorado, Aurora, Colorado
| | - Richard J Johnson
- Division of Renal Diseases and Hypertension, University of Colorado School of Medicine, University of Colorado, Aurora, Colorado
| | - Miguel A Lanaspa
- Division of Renal Diseases and Hypertension, University of Colorado School of Medicine, University of Colorado, Aurora, Colorado
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18
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Udagawa H, Hiramoto M, Kawaguchi M, Uebanso T, Ohara‐Imaizumi M, Nammo T, Nishimura W, Yasuda K. Characterization of the taste receptor-related G-protein, α-gustducin, in pancreatic β-cells. J Diabetes Investig 2020; 11:814-822. [PMID: 31957256 PMCID: PMC7378449 DOI: 10.1111/jdi.13214] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Revised: 01/06/2020] [Accepted: 01/15/2020] [Indexed: 01/17/2023] Open
Abstract
AIMS/INTRODUCTION Taste receptors, T1rs and T2rs, and the taste-selective G-protein, α-gustducin, are expressed outside the taste-sensing system, such as enteroendocrine L cells. Here, we examined whether α-gustducin also affects nutrition sensing and insulin secretion by pancreatic β-cells. MATERIALS AND METHODS The expression of α-gustducin and taste receptors was evaluated in β-cell lines, and in rat and mouse islets either by quantitative polymerase chain reaction or fluorescence immunostaining. The effects of α-gustducin knockdown on insulin secretion and on cyclic adenosine monophosphate and intracellular Ca2+ levels in rat INS-1 cells were estimated. Sucralose (taste receptor agonist)-induced insulin secretion was investigated in INS-1 cells with α-gustducin suppression and in islets from mouse disease models. RESULTS The expression of Tas1r3 and α-gustducin was confirmed in β-cell lines and pancreatic islets. Basal levels of cyclic adenosine monophosphate, intracellular calcium and insulin secretion were significantly enhanced with α-gustducin knockdown in INS-1 cells. The expression of α-gustducin was decreased in high-fat diet-fed mice and in diabetic db/db mice. Sucralose-induced insulin secretion was not attenuated in INS-1 cells with α-gustducin knockdown or in mouse islets with decreased expression of α-gustducin. CONCLUSIONS α-Gustducin is involved in the regulation of cyclic adenosine monophosphate, intracellular calcium levels and insulin secretion in pancreatic β-cells in a manner independent of taste receptor signaling. α-Gustducin might play a novel role in β-cell physiology and the development of type 2 diabetes.
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Affiliation(s)
- Haruhide Udagawa
- Department of Metabolic DisorderDiabetes Research CenterResearch InstituteNational Center for Global Health and MedicineTokyoJapan
- Department of Cellular BiochemistryKyorin University School of MedicineTokyoJapan
| | - Masaki Hiramoto
- Department of BiochemistryTokyo Medical UniversityTokyoJapan
| | - Miho Kawaguchi
- Department of Metabolic DisorderDiabetes Research CenterResearch InstituteNational Center for Global Health and MedicineTokyoJapan
| | - Takashi Uebanso
- Department of Preventive Environment and NutritionInstitute of Biomedical SciencesTokushima University Graduate SchoolTokushimaJapan
| | - Mica Ohara‐Imaizumi
- Department of Cellular BiochemistryKyorin University School of MedicineTokyoJapan
| | - Takao Nammo
- Department of Metabolic DisorderDiabetes Research CenterResearch InstituteNational Center for Global Health and MedicineTokyoJapan
| | - Wataru Nishimura
- Department of Molecular BiologyInternational University of Health and Welfare School of MedicineChibaJapan
- Division of AnatomyJichi Medical UniversityBio‐imaging and Neuro‐cell ScienceShimotsukeJapan
| | - Kazuki Yasuda
- Department of Metabolic DisorderDiabetes Research CenterResearch InstituteNational Center for Global Health and MedicineTokyoJapan
- Department of Diabetes, Endocrinology and MetabolismKyorin University School of MedicineTokyoJapan
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19
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Crowe MS, Wang H, Blakeney BA, Mahavadi S, Singh K, Murthy KS, Grider JR. Expression and function of umami receptors T1R1/T1R3 in gastric smooth muscle. Neurogastroenterol Motil 2020; 32:e13737. [PMID: 31721379 PMCID: PMC7008388 DOI: 10.1111/nmo.13737] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Revised: 08/19/2019] [Accepted: 09/16/2019] [Indexed: 02/01/2023]
Abstract
BACKGROUND l-amino acids, such as monosodium glutamate (MSG), activate the umami receptor T1R1/T1R3. We previously showed increased peristalsis in response to activation of T1R1/T1R3 by MSG in mouse colon. However, the expression and function of these receptors in the different regions of the stomach are not clear. METHODS Mouse gastric smooth muscle cells (SMCs) were isolated and cultured in Dulbecco's Modified Eagle Medium. Expression of T1R1 and T1R3 was measured by RT-PCR and Western blot. The effect of MSG with and without inosine monophosphate (IMP, an allosteric activator of T1R1/T1R3) on acetylcholine (ACh)-induced contraction was measured in muscle strips and isolated SMCs by scanning micrometry. The effect of MSG with or without IMP on activation of G proteins and ACh-induced Ca2+ release was measured in SMCs. KEY RESULTS Monosodium glutamate inhibited ACh-induced contractions in muscle strips from both antrum and fundus and the effect of MSG was augmented by IMP; the effects were concentration-dependent and not affected by the nitric oxide synthase inhibitor, L-NNA, or tetrodotoxin suggesting a direct effect on SMCs. In isolated gastric SMCs, T1R1 and T1R3 transcripts and protein were identified. Addition of MSG with or without IMP inhibited ACh-induced Ca2+ release and muscle contraction; the effect on contraction was blocked by pertussis toxin suggesting activation of Gαi proteins. MSG in the presence of IMP selectively activated Gαi2 . CONCLUSIONS AND INFERENCES Umami receptors (T1R1/T1R3) are present on SMCs of the stomach, and activation of these receptors induces muscle relaxation by decreasing [Ca2+ ]i via Gαi2 .
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Affiliation(s)
- Molly S. Crowe
- Department of Physiology and Biophysics VCU Program in Enteric Neuromuscular Sciences Virginia Commonwealth University Richmond VA USA
| | - Hongxia Wang
- Department of Physiology and Biophysics VCU Program in Enteric Neuromuscular Sciences Virginia Commonwealth University Richmond VA USA
| | - Bryan A. Blakeney
- Department of Physiology and Biophysics VCU Program in Enteric Neuromuscular Sciences Virginia Commonwealth University Richmond VA USA
| | - Sunila Mahavadi
- Department of Physiology and Biophysics VCU Program in Enteric Neuromuscular Sciences Virginia Commonwealth University Richmond VA USA
| | - Kulpreet Singh
- Department of Physiology and Biophysics VCU Program in Enteric Neuromuscular Sciences Virginia Commonwealth University Richmond VA USA
| | - Karnam S. Murthy
- Department of Physiology and Biophysics VCU Program in Enteric Neuromuscular Sciences Virginia Commonwealth University Richmond VA USA
| | - John R. Grider
- Department of Physiology and Biophysics VCU Program in Enteric Neuromuscular Sciences Virginia Commonwealth University Richmond VA USA
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20
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Howitt MR, Cao YG, Gologorsky MB, Li JA, Haber AL, Biton M, Lang J, Michaud M, Regev A, Garrett WS. The Taste Receptor TAS1R3 Regulates Small Intestinal Tuft Cell Homeostasis. Immunohorizons 2020; 4:23-32. [PMID: 31980480 PMCID: PMC7197368 DOI: 10.4049/immunohorizons.1900099] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Accepted: 01/08/2020] [Indexed: 01/06/2023] Open
Abstract
Tuft cells are an epithelial cell type critical for initiating type 2 immune responses to parasites and protozoa in the small intestine. To respond to these stimuli, intestinal tuft cells use taste chemosensory signaling pathways, but the role of taste receptors in type 2 immunity is poorly understood. In this study, we show that the taste receptor TAS1R3, which detects sweet and umami in the tongue, also regulates tuft cell responses in the distal small intestine. BALB/c mice, which have an inactive form of TAS1R3, as well as Tas1r3-deficient C57BL6/J mice both have severely impaired responses to tuft cell–inducing signals in the ileum, including the protozoa Tritrichomonas muris and succinate. In contrast, TAS1R3 is not required to mount an immune response to the helminth Heligmosomoides polygyrus, which infects the proximal small intestine. Examination of uninfected Tas1r3−/− mice revealed a modest reduction in the number of tuft cells in the proximal small intestine but a severe decrease in the distal small intestine at homeostasis. Together, these results suggest that TAS1R3 influences intestinal immunity by shaping the epithelial cell landscape at steady-state. ImmunoHorizons, 2020, 4: 23–32.
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Affiliation(s)
- Michael R Howitt
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA 02115; .,Department of Molecular Metabolism, Harvard T.H. Chan School of Public Health, Boston, MA 02115.,Department of Pathology, Stanford University, Stanford, CA 94305
| | - Y Grace Cao
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA 02115.,Department of Molecular Metabolism, Harvard T.H. Chan School of Public Health, Boston, MA 02115
| | | | - Jessica A Li
- Department of Pathology, Stanford University, Stanford, CA 94305
| | - Adam L Haber
- Broad Institute of MIT and Harvard, Cambridge, MA 02142
| | - Moshe Biton
- Broad Institute of MIT and Harvard, Cambridge, MA 02142.,Department of Biological Regulation, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Jessica Lang
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA 02115.,Department of Molecular Metabolism, Harvard T.H. Chan School of Public Health, Boston, MA 02115
| | - Monia Michaud
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA 02115.,Department of Molecular Metabolism, Harvard T.H. Chan School of Public Health, Boston, MA 02115
| | - Aviv Regev
- Broad Institute of MIT and Harvard, Cambridge, MA 02142.,Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA 02142.,Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02142.,Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02142; and
| | - Wendy S Garrett
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA 02115; .,Department of Molecular Metabolism, Harvard T.H. Chan School of Public Health, Boston, MA 02115.,Broad Institute of MIT and Harvard, Cambridge, MA 02142.,Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA 02215
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21
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Merino B, Fernández-Díaz CM, Cózar-Castellano I, Perdomo G. Intestinal Fructose and Glucose Metabolism in Health and Disease. Nutrients 2019; 12:E94. [PMID: 31905727 PMCID: PMC7019254 DOI: 10.3390/nu12010094] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2019] [Revised: 12/26/2019] [Accepted: 12/26/2019] [Indexed: 02/06/2023] Open
Abstract
The worldwide epidemics of obesity and diabetes have been linked to increased sugar consumption in humans. Here, we review fructose and glucose metabolism, as well as potential molecular mechanisms by which excessive sugar consumption is associated to metabolic diseases and insulin resistance in humans. To this end, we focus on understanding molecular and cellular mechanisms of fructose and glucose transport and sensing in the intestine, the intracellular signaling effects of dietary sugar metabolism, and its impact on glucose homeostasis in health and disease. Finally, the peripheral and central effects of dietary sugars on the gut-brain axis will be reviewed.
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Affiliation(s)
- Beatriz Merino
- Instituto de Biología y Genética Molecular-IBGM (CSIC-Universidad de Valladolid), Valladolid 47003, Spain; (B.M.); (C.M.F.-D.); (G.P.)
| | - Cristina M. Fernández-Díaz
- Instituto de Biología y Genética Molecular-IBGM (CSIC-Universidad de Valladolid), Valladolid 47003, Spain; (B.M.); (C.M.F.-D.); (G.P.)
| | - Irene Cózar-Castellano
- Instituto de Biología y Genética Molecular-IBGM (CSIC-Universidad de Valladolid), Valladolid 47003, Spain; (B.M.); (C.M.F.-D.); (G.P.)
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Madrid 28029, Spain
| | - German Perdomo
- Instituto de Biología y Genética Molecular-IBGM (CSIC-Universidad de Valladolid), Valladolid 47003, Spain; (B.M.); (C.M.F.-D.); (G.P.)
- Departamento de Ciencias de la Salud, Universidad de Burgos, Burgos 09001, Spain
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22
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Tian M, Heng J, Song H, Zhang Y, Chen F, Guan W, Zhang S. Branched chain amino acids stimulate gut satiety hormone cholecystokinin secretion through activation of the umami taste receptor T1R1/T1R3 using an in vitro porcine jejunum model. Food Funct 2019; 10:3356-3367. [PMID: 31098606 DOI: 10.1039/c9fo00228f] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Branched chain amino acids (BCAAs) are essential amino acids involved in regulation of feed intake. The function of BCAAs on the central nervous system has been extensively studied, but effects of BCAAs on secretion of gut satiety hormones and their underlying mechanisms are largely unknown. In this study, we evaluated the distribution of gut hormones and amino acid receptors in the porcine GI tract and found cholecystokinin (CCK) and taste dimeric receptor type 1 member 1/3 (T1R1/T1R3) were predominantly expressed in the jejunum and functionally interrelated. We further evaluated the effects of l-leucine, l-isoleucine, l-valine, and BCAAs on CCK and T1R1/T1R3 expression in porcine jejunum tissue. Our data demonstrated that stimulation of porcine jejunum tissue with 10 mM l-leucine, l-isoleucine or BCAAs mix (l-leucine : l-isoleucine : l-valine = 1 : 0.51 : 0.63) for 2 hours significantly increased mRNA expression and protein abundance of T1R1/T1R3 and secretion of CCK (P < 0.05). However, the l-valine treatment only increased the mRNA and protein abundance of T1R1 and T1R3 (P < 0.05), but not CCK secretion (P > 0.10). l-Leucine-, l-isoleucine- or BCAAs mix-induced CCK secretion was significantly decreased after tissues were pretreated with lactisole, a T1R1/T1R3 inhibitor (P < 0.05). Furthermore, the increased mRNA and protein abundance of T1R1/T1R3 were also largely attenuated by blocking T1R1/T1R3 with lactisole (P < 0.05). l-Leucine, l-isoleucine and BCAAs mix appeared to induce the gut satiety hormone CCK secretion through jejunal T1R1/T1R3. These results indicate over-supplementation with BCAAs in the diet might decrease food intake in swine and humans through gastrointestinal feedback.
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Affiliation(s)
- Min Tian
- Guangdong Provincial Key Laboratory of Animal Nutrition Control, College of Animal Science, South China Agricultural University, Guangzhou 510642, People's Republic of China.
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23
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Martin AM, Sun EW, Keating DJ. Mechanisms controlling hormone secretion in human gut and its relevance to metabolism. J Endocrinol 2019; 244:R1-R15. [PMID: 31751295 PMCID: PMC6892457 DOI: 10.1530/joe-19-0399] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2019] [Accepted: 11/18/2019] [Indexed: 12/16/2022]
Abstract
The homoeostatic regulation of metabolism is highly complex and involves multiple inputs from both the nervous and endocrine systems. The gut is the largest endocrine organ in our body and synthesises and secretes over 20 different hormones from enteroendocrine cells that are dispersed throughout the gut epithelium. These hormones include GLP-1, PYY, GIP, serotonin, and CCK, each of whom play pivotal roles in maintaining energy balance and glucose homeostasis. Some are now the basis of several clinically used glucose-lowering and weight loss therapies. The environment in which these enteroendocrine cells exist is also complex, as they are exposed to numerous physiological inputs including ingested nutrients, circulating factors and metabolites produced from neighbouring gut microbiome. In this review, we examine the diverse means by which gut-derived hormones carry out their metabolic functions through their interactions with different metabolically important organs including the liver, pancreas, adipose tissue and brain. Furthermore, we discuss how nutrients and microbial metabolites affect gut hormone secretion and the mechanisms underlying these interactions.
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Affiliation(s)
- Alyce M Martin
- College of Medicine and Public Health, Flinders University, Adelaide, South Australia, Australia
| | - Emily W Sun
- College of Medicine and Public Health, Flinders University, Adelaide, South Australia, Australia
| | - Damien J Keating
- College of Medicine and Public Health, Flinders University, Adelaide, South Australia, Australia
- Nutrition and Metabolism, South Australian Health and Medical Research Institute, Adelaide, South Australia, Australia
- Correspondence should be addressed to D J Keating:
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Sarnelli G, Annunziata G, Magno S, Oriolo C, Savastano S, Colao A. Taste and the Gastrointestinal tract: from physiology to potential therapeutic target for obesity. INTERNATIONAL JOURNAL OF OBESITY SUPPLEMENTS 2019; 9:1-9. [PMID: 31391920 DOI: 10.1038/s41367-019-0012-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Flavor is the combination of gustatory, olfactory and trigeminal sensations, representing the three main sensory pathways that allow detecting environmental chemical substances. Taste, in particular, is a complex chemosensory path that allows identification of substances present in ingested foods and beverages. In this manuscript, we propose a conceptual roadmap from aspects related to the evolution and the physiological role of taste, up to the current knowledge about its implication in the modulation of a healthy state, or obesity. More specifically, we focused on the role of stimulation of taste receptors in releasing gut hormones (also known as enterohormones), and their effects on the regulation of food intake, by inducing satiety, either by locally acting (in the gastrointestinal tract), or centrally (in the brain). Recent evidence demonstrated that some enterohormones are able to modulate gastrointestinal motility, thus affecting an orexigenic responses in the central nervous system. In keeping with this, we discuss the ability of the gustatory system to be a final checkpoint control for food intake regulation, and we speculate about taste perception manipulation in the management of obesity.
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Affiliation(s)
- Giovanni Sarnelli
- 1Department of Clinical Medicine and Surgery, Division of Gastroenterology, University of Naples Federico II, Naples, Italy
| | | | - Silvia Magno
- Obesity Center at the Endocrinology Unit, Department of Clinical and Experimental Medicine, Pisa, Italy
| | - Claudia Oriolo
- 4Endocrinology Unit, Medical Department of Care Continuity and Disability, University of Bologna, Bologna, Italy
| | - Silvia Savastano
- 5Dipartimento di Medicina Clinica e Chirurgia, Unit of Endocrinology, Federico II University Medical School of Naples, Napoli, Italy
| | - Annamaria Colao
- 5Dipartimento di Medicina Clinica e Chirurgia, Unit of Endocrinology, Federico II University Medical School of Naples, Napoli, Italy
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Abstract
Taste pathways in humans and other primates project from the nucleus of the solitary tract directly to the taste thalamus, and then to the taste insula. The taste cortex in the anterior insula provides separate and combined representations of the taste, temperature, and texture of food in the mouth independently of hunger and thus of reward value and pleasantness. One synapse on, in the orbitofrontal cortex, these sensory inputs are for some neurons combined by associative learning with olfactory inputs received from the pyriform cortex, and visual inputs from the temporal lobe, and these neurons encode food reward value in that they only respond to food when hungry, and in that activations correlate linearly with subjective pleasantness. Cognitive factors, including word-level descriptions, and selective attention to affective value, modulate the representation of the reward value of taste, olfactory and flavor stimuli in the orbitofrontal cortex and a region to which it projects, the anterior cingulate cortex. These food reward representations are important in the control of appetite, and the liking of food. Individual differences in these reward representations may contribute to obesity, and there are age-related differences in these reward representations.
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Affiliation(s)
- Edmund T Rolls
- Oxford Centre for Computational Neuroscience, Oxford, United Kingdom.
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26
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Smith K, Karimian Azari E, LaMoia TE, Hussain T, Vargova V, Karolyi K, Veldhuis PP, Arnoletti JP, de la Fuente SG, Pratley RE, Osborne TF, Kyriazis GA. T1R2 receptor-mediated glucose sensing in the upper intestine potentiates glucose absorption through activation of local regulatory pathways. Mol Metab 2018; 17:98-111. [PMID: 30201274 PMCID: PMC6197762 DOI: 10.1016/j.molmet.2018.08.009] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Revised: 08/09/2018] [Accepted: 08/22/2018] [Indexed: 12/21/2022] Open
Abstract
Objective Beyond the taste buds, sweet taste receptors (STRs; T1R2/T1R3) are also expressed on enteroendocrine cells, where they regulate gut peptide secretion but their regulatory function within the intestine is largely unknown. Methods Using T1R2-knock out (KO) mice we evaluated the role of STRs in the regulation of glucose absorption in vivo and in intact intestinal preparations ex vivo. Results STR signaling enhances the rate of intestinal glucose absorption specifically in response to the ingestion of a glucose-rich meal. These effects were mediated specifically by the regulation of GLUT2 transporter trafficking to the apical membrane of enterocytes. GLUT2 translocation and glucose transport was dependent and specific to glucagon-like peptide 2 (GLP-2) secretion and subsequent intestinal neuronal activation. Finally, high-sucrose feeding in wild-type mice induced rapid downregulation of STRs in the gut, leading to reduced glucose absorption. Conclusions Our studies demonstrate that STRs have evolved to modulate glucose absorption via the regulation of its transport and to prevent the development of exacerbated hyperglycemia due to the ingestion of high levels of sugars. The intestinal T1R2 receptor enhances glucose absorption in vivo and ex vivo. Pharmacological inhibition of STRs reduces glucose flux in human intestinal preparations. T1R2 regulates glucose absorption dependent on GLUT2 activity in enterocytes. GLP-2 mediates the effects of T1R2 signaling through activation of enteric neurons. High sucrose diet rapidly downregulates STRs leading to reduced glucose absorption.
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Affiliation(s)
- Kathleen Smith
- Center for Metabolic Origins of Disease, Sanford Burnham Prebys Medical Discovery Institute, Orlando, FL, USA
| | - Elnaz Karimian Azari
- Center for Metabolic Origins of Disease, Sanford Burnham Prebys Medical Discovery Institute, Orlando, FL, USA
| | - Traci E LaMoia
- Center for Metabolic Origins of Disease, Sanford Burnham Prebys Medical Discovery Institute, Orlando, FL, USA
| | - Tania Hussain
- Center for Metabolic Origins of Disease, Sanford Burnham Prebys Medical Discovery Institute, Orlando, FL, USA
| | - Veronika Vargova
- Translational Research Institute for Metabolism and Diabetes, Florida Hospital, Orlando, FL, USA
| | - Katalin Karolyi
- Center for Metabolic Origins of Disease, Sanford Burnham Prebys Medical Discovery Institute, Orlando, FL, USA
| | - Paula P Veldhuis
- Institute for Surgical Advancement, Florida Hospital, Orlando, FL, USA
| | | | | | - Richard E Pratley
- Translational Research Institute for Metabolism and Diabetes, Florida Hospital, Orlando, FL, USA
| | - Timothy F Osborne
- Center for Metabolic Origins of Disease, Sanford Burnham Prebys Medical Discovery Institute, Orlando, FL, USA
| | - George A Kyriazis
- Center for Metabolic Origins of Disease, Sanford Burnham Prebys Medical Discovery Institute, Orlando, FL, USA; Translational Research Institute for Metabolism and Diabetes, Florida Hospital, Orlando, FL, USA; Department of Biological Chemistry and Pharmacology, College of Medicine, The Ohio State University, Columbus, OH, USA.
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27
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Ma J, Vella A. What Has Bariatric Surgery Taught Us About the Role of the Upper Gastrointestinal Tract in the Regulation of Postprandial Glucose Metabolism? Front Endocrinol (Lausanne) 2018; 9:324. [PMID: 29997575 PMCID: PMC6028568 DOI: 10.3389/fendo.2018.00324] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Accepted: 05/31/2018] [Indexed: 02/06/2023] Open
Abstract
The interaction between the upper gastrointestinal tract and the endocrine system is important in the regulation of metabolism and of weight. The gastrointestinal tract has a heterogeneous cellular content and comprises a variety of cells that elaborate paracrine and endocrine mediators that collectively form the entero-endocrine system. The advent of therapy that utilizes these pathways as well as the association of bariatric surgery with diabetes remission has (re-)kindled interest in the role of the gastrointestinal tract in glucose homeostasis. In this review, we will use the changes wrought by bariatric surgery to provide insights into the various gut-pancreas interactions that maintain weight, regulate satiety, and limit glucose excursions after meal ingestion.
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Affiliation(s)
- Jing Ma
- Division of Endocrinology and Metabolism, Shanghai Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China
- Division of Endocrinology, Diabetes and Metabolism, Mayo Clinic College of Medicine, Rochester, NY, United States
| | - Adrian Vella
- Division of Endocrinology, Diabetes and Metabolism, Mayo Clinic College of Medicine, Rochester, NY, United States
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Paternoster S, Falasca M. Dissecting the Physiology and Pathophysiology of Glucagon-Like Peptide-1. Front Endocrinol (Lausanne) 2018; 9:584. [PMID: 30364192 PMCID: PMC6193070 DOI: 10.3389/fendo.2018.00584] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Accepted: 09/14/2018] [Indexed: 12/11/2022] Open
Abstract
An aging world population exposed to a sedentary life style is currently plagued by chronic metabolic diseases, such as type-2 diabetes, that are spreading worldwide at an unprecedented rate. One of the most promising pharmacological approaches for the management of type 2 diabetes takes advantage of the peptide hormone glucagon-like peptide-1 (GLP-1) under the form of protease resistant mimetics, and DPP-IV inhibitors. Despite the improved quality of life, long-term treatments with these new classes of drugs are riddled with serious and life-threatening side-effects, with no overall cure of the disease. New evidence is shedding more light over the complex physiology of GLP-1 in health and metabolic diseases. Herein, we discuss the most recent advancements in the biology of gut receptors known to induce the secretion of GLP-1, to bridge the multiple gaps into our understanding of its physiology and pathology.
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Abstract
Many people avidly consume foods and drinks containing caffeine, despite its bitter taste. Here, we review what is known about caffeine as a bitter taste stimulus. Topics include caffeine's action on the canonical bitter taste receptor pathway and caffeine's action on noncanonical receptor-dependent and -independent pathways in taste cells. Two conclusions are that (1) caffeine is a poor prototypical bitter taste stimulus because it acts on bitter taste receptor-independent pathways, and (2) caffeinated products most likely stimulate "taste" receptors in nongustatory cells. This review is relevant for taste researchers, manufacturers of caffeinated products, and caffeine consumers.
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Affiliation(s)
- Rachel L Poole
- Monell Chemical Senses Center, Philadelphia, Pennsylvania
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30
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Steviol glycosides enhance pancreatic beta-cell function and taste sensation by potentiation of TRPM5 channel activity. Nat Commun 2017; 8:14733. [PMID: 28361903 PMCID: PMC5380970 DOI: 10.1038/ncomms14733] [Citation(s) in RCA: 116] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Accepted: 01/26/2017] [Indexed: 02/07/2023] Open
Abstract
Steviol glycosides (SGs), such as stevioside and rebaudioside A, are natural, non-caloric sweet-tasting organic molecules, present in extracts of the scrub plant Stevia rebaudiana, which are widely used as sweeteners in consumer foods and beverages. TRPM5 is a Ca2+-activated cation channel expressed in type II taste receptor cells and pancreatic β-cells. Here we show that stevioside, rebaudioside A and their aglycon steviol potentiate the activity of TRPM5. We find that SGs potentiate perception of bitter, sweet and umami taste, and enhance glucose-induced insulin secretion in a Trpm5-dependent manner. Daily consumption of stevioside prevents development of high-fat-diet-induced diabetic hyperglycaemia in wild-type mice, but not in Trpm5-/- mice. These results elucidate a molecular mechanism of action of SGs and identify TRPM5 as a potential target to prevent and treat type 2 diabetes.
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31
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Kochem M, Breslin PAS. Clofibrate inhibits the umami-savory taste of glutamate. PLoS One 2017; 12:e0172534. [PMID: 28248971 PMCID: PMC5332072 DOI: 10.1371/journal.pone.0172534] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Accepted: 02/06/2017] [Indexed: 01/21/2023] Open
Abstract
In humans, umami taste can increase the palatability of foods rich in the amino acids glutamate and aspartate and the 5'-ribonucleotides IMP and GMP. Umami taste is transduced, in part, by T1R1-T1R3, a heteromeric G-protein coupled receptor. Umami perception is inhibited by sodium lactisole, which binds to the T1R3 subunit in vitro. Lactisole is structurally similar to the fibrate drugs. Clofibric acid, a lipid lowering drug, also binds the T1R3 subunit in vitro. The purpose of this study was to determine whether clofibric acid inhibits the umami taste of glutamate in human subjects. Ten participants rated the umami taste intensity elicited by 20 mM monosodium glutamate (MSG) mixed with varying concentrations of clofibric acid (0 to 16 mM). In addition, fourteen participants rated the effect of 1.4 mM clofibric acid on umami enhancement by 5' ribonucleotides. Participants were instructed to rate perceived intensity using a general Labeled Magnitude Scale (gLMS). Each participant was tested in triplicate. Clofibric acid inhibited umami taste intensity from 20 mM MSG in a dose dependent manner. Whereas MSG neat elicited "moderate" umami taste intensity, the addition of 16 mM clofibric acid elicited only "weak" umami intensity on average, and in some subjects no umami taste was elicited. We further show that 1.4 mM clofibric acid suppressed umami enhancement from GMP, but not from IMP. This study provides in vivo evidence that clofibric acid inhibits glutamate taste perception, presumably via T1R1-T1R3 inhibition, and lends further evidence that the T1R1-T1R3 receptor is the principal umami receptor in humans. T1R receptors are expressed extra-orally throughout the alimentary tract and in regulatory organs and are known to influence glucose and lipid metabolism. Whether clofibric acid as a lipid-lowering drug affects human metabolism, in part, through T1R inhibition warrants further examination.
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Affiliation(s)
- Matthew Kochem
- Rutgers University Department of Nutritional Sciences, New Brunswick, NJ, United States of America
| | - Paul A. S. Breslin
- Rutgers University Department of Nutritional Sciences, New Brunswick, NJ, United States of America
- Monell Chemical Senses Center Philadelphia, PA, United States of America
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32
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Affiliation(s)
- Edmund T. Rolls
- Oxford Centre for Computational Neuroscience, Oxford, United Kingdom;
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33
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Impact of obesity on taste receptor expression in extra-oral tissues: emphasis on hypothalamus and brainstem. Sci Rep 2016; 6:29094. [PMID: 27388805 PMCID: PMC4937374 DOI: 10.1038/srep29094] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 06/14/2016] [Indexed: 12/16/2022] Open
Abstract
Sweet perception promotes food intake, whereas that of bitterness is inhibitory. Surprisingly, the expression of sweet G protein-coupled taste receptor (GPCTR) subunits (T1R2 and T1R3) and bitter GPCTRs (T2R116, T2R118, T2R138 and T2R104), as well as the α-subunits of the associated signalling complex (αGustducin, Gα14 and αTransducin), in oral and extra-oral tissues from lean and obese mice, remains poorly characterized. We focused on the impact of obesity on taste receptor expression in brain areas involved in energy homeostasis, namely the hypothalamus and brainstem. We demonstrate that many of the GPCTRs and α-subunits are co-expressed in these tissues and that obesity decreases expression of T1R3, T2R116, Gα14, αTrans and TRPM5. In vitro high levels of glucose caused a prominent down-regulation of T1R2 and Gα14 expression in cultured hypothalamic neuronal cells, leptin caused a transient down-regulation of T1R2 and T1R3 expression. Intriguingly, expression differences were also observed in other extra-oral tissues of lean and obese mice, most strikingly in the duodenum where obesity reduced the expression of most bitter and sweet receptors. In conclusion, obesity influences components of sweet and bitter taste sensing in the duodenum as well as regions of the mouse brain involved in energy homeostasis, including hypothalamus and brainstem.
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Smith KR, Hussain T, Karimian Azari E, Steiner JL, Ayala JE, Pratley RE, Kyriazis GA. Disruption of the sugar-sensing receptor T1R2 attenuates metabolic derangements associated with diet-induced obesity. Am J Physiol Endocrinol Metab 2016; 310:E688-E698. [PMID: 26884387 PMCID: PMC4835941 DOI: 10.1152/ajpendo.00484.2015] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Accepted: 02/12/2016] [Indexed: 11/22/2022]
Abstract
Sweet taste receptors (STRs) on the tongue mediate gustatory sweet sensing, but their expression in the gut, pancreas, and adipose tissue suggests a physiological contribution to whole body nutrient sensing and metabolism. However, little is known about the function and contribution of these sugar sensors during metabolic stress induced by overnutrition and subsequent obesity. Here, we investigated the effects of high-fat/low-carbohydrate (HF/LC) diet on glucose homeostasis and energy balance in mice with global disruption of the sweet taste receptor protein T1R2. We assessed body composition, energy balance, glucose homeostasis, and tissue-specific nutrient metabolism in T1R2 knockout (T1R2-KO) mice fed a HF/LC diet for 12 wk. HF/LC diet-fed T1R2-KO mice gained a similar amount of body mass as did WT mice, but had reduced fat mass and increased lean mass relative to WT mice. T1R2-KO mice were also hyperphagic and hyperactive. Ablation of the T1R2 sugar sensor protected mice from HF/LC diet-induced hyperinsulinemia and altered substrate utilization, including increased rates of glucose oxidation and decreased liver triglyceride (TG) accumulation, despite normal intestinal fat absorption. Finally, STRs (T1r2/T1r3) were upregulated in the adipose tissue of WT mice in response to HF/LC diet, and their expression positively correlated with fat mass and glucose intolerance. The chemosensory receptor T1R2, plays an important role in glucose homeostasis during diet-induced obesity through the regulation of yet to be identified molecular mechanisms that alter energy disposal and utilization in peripheral tissues.
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Affiliation(s)
- Kathleen R Smith
- Center for Metabolic Origins of Disease, Sanford Burnham Prebys Medical Discovery Institute, Orlando, Florida; and
| | - Tania Hussain
- Center for Metabolic Origins of Disease, Sanford Burnham Prebys Medical Discovery Institute, Orlando, Florida; and
| | - Elnaz Karimian Azari
- Center for Metabolic Origins of Disease, Sanford Burnham Prebys Medical Discovery Institute, Orlando, Florida; and
| | - Jennifer L Steiner
- Center for Metabolic Origins of Disease, Sanford Burnham Prebys Medical Discovery Institute, Orlando, Florida; and
| | - Julio E Ayala
- Center for Metabolic Origins of Disease, Sanford Burnham Prebys Medical Discovery Institute, Orlando, Florida; and
| | - Richard E Pratley
- Center for Metabolic Origins of Disease, Sanford Burnham Prebys Medical Discovery Institute, Orlando, Florida; and
- Translational Research Institute for Metabolism and Diabetes, Florida Hospital, Orlando, Florida
| | - George A Kyriazis
- Center for Metabolic Origins of Disease, Sanford Burnham Prebys Medical Discovery Institute, Orlando, Florida; and
- Translational Research Institute for Metabolism and Diabetes, Florida Hospital, Orlando, Florida
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Song P, Onishi A, Koepsell H, Vallon V. Sodium glucose cotransporter SGLT1 as a therapeutic target in diabetes mellitus. Expert Opin Ther Targets 2016; 20:1109-25. [PMID: 26998950 DOI: 10.1517/14728222.2016.1168808] [Citation(s) in RCA: 113] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
INTRODUCTION Glycemic control is important in diabetes mellitus to minimize the progression of the disease and the risk of potentially devastating complications. Inhibition of the sodium-glucose cotransporter SGLT2 induces glucosuria and has been established as a new anti-hyperglycemic strategy. SGLT1 plays a distinct and complementing role to SGLT2 in glucose homeostasis and, therefore, SGLT1 inhibition may also have therapeutic potential. AREAS COVERED This review focuses on the physiology of SGLT1 in the small intestine and kidney and its pathophysiological role in diabetes. The therapeutic potential of SGLT1 inhibition, alone as well as in combination with SGLT2 inhibition, for anti-hyperglycemic therapy are discussed. Additionally, this review considers the effects on other SGLT1-expressing organs like the heart. EXPERT OPINION SGLT1 inhibition improves glucose homeostasis by reducing dietary glucose absorption in the intestine and by increasing the release of gastrointestinal incretins like glucagon-like peptide-1. SGLT1 inhibition has a small glucosuric effect in the normal kidney and this effect is increased in diabetes and during inhibition of SGLT2, which deliver more glucose to SGLT1 in late proximal tubule. In short-term studies, inhibition of SGLT1 and combined SGLT1/SGLT2 inhibition appeared to be safe. More data is needed on long-term safety and cardiovascular consequences of SGLT1 inhibition.
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Affiliation(s)
- Panai Song
- a Division of Nephrology & Hypertension, Department of Medicine , University of California San Diego , La Jolla , CA , USA.,b VA San Diego Healthcare System , San Diego , CA , USA.,c Department of Nephrology, Second Xiangya Hospital , Central South University , Changsha , China
| | - Akira Onishi
- a Division of Nephrology & Hypertension, Department of Medicine , University of California San Diego , La Jolla , CA , USA.,b VA San Diego Healthcare System , San Diego , CA , USA.,d Division of Nephrology, Department of Medicine , Jichi Medical University , Shimotsuke , Japan
| | - Hermann Koepsell
- e Department of Molecular Plant Physiology and Biophysics, Julius-von-Sachs-Institute , University of Würzburg , Würzburg , Germany
| | - Volker Vallon
- a Division of Nephrology & Hypertension, Department of Medicine , University of California San Diego , La Jolla , CA , USA.,b VA San Diego Healthcare System , San Diego , CA , USA.,f Department of Pharmacology , University of California San Diego , La Jolla , CA , USA
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36
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Abstract
The incretin hormones glucose-dependent insulinotropic polypeptide (GIP) and glucagon like peptide-1 (GLP-1) are secreted from enteroendocrine cells in the gut and regulate physiological and homeostatic functions related to glucose control, metabolism and food intake. This review provides a systematic summary of the molecular mechanisms underlying secretion from incretin cells, and an understanding of how they sense and interact with lumen and vascular factors and the enteric nervous system through transporters and G-protein coupled receptors (GPCRs) present on their surface to ultimately culminate in hormone release. Some of the molecules described below such as sodium coupled glucose transporter 1 (SGLT1), G-protein coupled receptor (GPR) 119 and GPR40 are targets of novel therapeutics designed to enhance endogenous gut hormone release. Synthetic ligands at these receptors aimed at treating obesity and type 2 diabetes are currently under investigation.
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Affiliation(s)
- Ramona Pais
- The Wellcome Trust–MRC Institute of Metabolic Science, Metabolic Research Laboratories, University of Cambridge, Cambridge, UK
| | - Fiona M. Gribble
- The Wellcome Trust–MRC Institute of Metabolic Science, Metabolic Research Laboratories, University of Cambridge, Addenbrookes’s Hospital, Box 289, Hills Road, Cambridge, CB2 0QQ, UK
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Ciullo DL, Dotson CD. Using Animal Models to Determine the Role of Gustatory Neural Input in the Control of Ingestive Behavior and the Maintenance of Body Weight. CHEMOSENS PERCEPT 2015; 8:61-77. [PMID: 26557212 PMCID: PMC4636125 DOI: 10.1007/s12078-015-9190-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
INTRODUCTION Decades of research have suggested that nutritional intake contributes to the development of human disease, mainly by influencing the development of obesity and obesity-related conditions. A relatively large body of research indicates that functional variation in human taste perception can influence nutritional intake as well as body mass accumulation. However, there are a considerable number of studies that suggest that no link between these variables actually exists. These discrepancies in the literature likely result from the confounding influence of a variety of other, uncontrolled, factors that can influence ingestive behavior. STRATEGY In this review, the use of controlled animal experimentation to alleviate at least some of these issues related to the lack of control of experimental variables is discussed. Specific examples of the use of some of these techniques are examined. DISCUSSION AND CONCLUSIONS The review will close with some specific suggestions aimed at strengthening the link between gustatory neural input and its putative influence on ingestive behaviors and the maintenance of body weight.
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Affiliation(s)
- Dana L Ciullo
- Departments of Neuroscience and Psychiatry, Division of Addiction Medicine, University of Florida College of Medicine, and Center for Smell and Taste, University of Florida, Gainesville, FL 32611, USA,
| | - Cedrick D Dotson
- Departments of Neuroscience and Psychiatry, Division of Addiction Medicine, University of Florida College of Medicine, and Center for Smell and Taste, University of Florida, Gainesville, FL 32611, USA,
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40
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Pepino MY. Metabolic effects of non-nutritive sweeteners. Physiol Behav 2015; 152:450-5. [PMID: 26095119 DOI: 10.1016/j.physbeh.2015.06.024] [Citation(s) in RCA: 156] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Revised: 05/20/2015] [Accepted: 06/17/2015] [Indexed: 12/22/2022]
Abstract
Until recently, the general belief was that non-nutritive sweeteners (NNSs) were healthy sugar substitutes because they provide sweet taste without calories or glycemic effects. However, data from several epidemiological studies have found that consumption of NNSs, mainly in diet sodas, is associated with increased risk to develop obesity, metabolic syndrome, and type 2 diabetes. The main purpose of this article is to review recent scientific evidence supporting potential mechanisms that explain how "metabolically inactive" NNSs, which have few, if any, calories, might promote metabolic dysregulation. Three potential mechanisms, which are not mutually exclusive, are presented: 1) NNSs interfere with learned responses that contribute to control glucose and energy homeostasis, 2) NNSs interfere with gut microbiota and induce glucose intolerance, and 3) NNSs interact with sweet-taste receptors expressed throughout the digestive system that play a role in glucose absorption and trigger insulin secretion. In addition, recent findings from our laboratory showing an association between individual taste sensitivity to detect sucralose and sucralose's acute effects on metabolic response to an oral glucose load are reported. Taken as a whole, data support the notion that NNSs have metabolic effects. More research is needed to elucidate the mechanisms by which NNSs may drive metabolic dysregulation and better understand potential effects of these commonly used food additives.
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Affiliation(s)
- M Yanina Pepino
- Center for Human Nutrition, Washington University School of Medicine, St. Louis, MO, United States.
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Abstract
Levels of obesity have reached epidemic proportions on a global scale, which has led to considerable increases in health problems and increased risk of several diseases, including cardiovascular and pulmonary diseases, cancer and diabetes mellitus. People with obesity consume more food than is needed to maintain an ideal body weight, despite the discrimination that accompanies being overweight and the wealth of available information that overconsumption is detrimental to health. The relationship between energy expenditure and energy intake throughout an individual's lifetime is far more complicated than previously thought. An improved comprehension of the relationships between taste, palatability, taste receptors and hedonic responses to food might lead to increased understanding of the biological underpinnings of energy acquisition, as well as why humans sometimes eat more than is needed and more than we know is healthy. This Review discusses the role of taste receptors in the tongue, gut, pancreas and brain and their hormonal involvement in taste perception, as well as the relationship between taste perception, overeating and the development of obesity.
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Affiliation(s)
- Sara Santa-Cruz Calvo
- Laboratory of Clinical Investigation, National Institute on Aging, NIH, Biomedical Research Center, Room 09B133, 251 Bayview Boulevard, Suite 100, Baltimore, MD 21224-6825, USA
| | - Josephine M Egan
- Laboratory of Clinical Investigation, National Institute on Aging, NIH, Biomedical Research Center, Room 09B133, 251 Bayview Boulevard, Suite 100, Baltimore, MD 21224-6825, USA
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Resistant maltodextrin promotes fasting glucagon-like peptide-1 secretion and production together with glucose tolerance in rats. Br J Nutr 2015; 114:34-42. [PMID: 25671387 DOI: 10.1017/s0007114514004322] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Glucagon-like peptide-1 (GLP-1), which is produced and released from enteroendocrine L cells, plays pivotal roles in postprandial glycaemia. The ingestion of resistant maltodextrin (RMD), a water-soluble non-digestible saccharide, improves the glycaemic response. In the present study, we examined whether the continuous feeding of RMD to rats affected GLP-1 levels and glycaemic control. Male Sprague-Dawley rats (6 weeks of age) were fed an American Institute of Nutrition (AIN)-93G-based diet containing either cellulose (5 %) as a control, RMD (2.5 or 5 %), or fructo-oligosaccharides (FOS, 2.5 or 5 %) for 7 weeks. During the test period, an intraperitoneal glucose tolerance test (IPGTT) was performed after 6 weeks. Fasting GLP-1 levels were significantly higher in the 5 % RMD group than in the control group after 6 weeks. The IPGTT results showed that the glycaemic response was lower in the 5 % RMD group than in the control group. Lower caecal pH, higher caecal tissue and content weights were observed in the RMD and FOS groups. Proglucagon mRNA levels were increased in the caecum and colon of both RMD and FOS groups, whereas caecal GLP-1 content was increased in the 5 % RMD group. In addition, a 1 h RMD exposure induced GLP-1 secretion in an enteroendocrine L-cell model, and single oral administration of RMD increased plasma GLP-1 levels in conscious rats. The present study demonstrates that continuous ingestion of RMD increased GLP-1 secretion and production in normal rats, which could be stimulated by its direct and indirect (enhanced gut fermentation) effects on GLP-1-producing cells, and contribute to improving glucose tolerance.
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Jaber L, Zhao FL, Kolli T, Herness S. A physiologic role for serotonergic transmission in adult rat taste buds. PLoS One 2014; 9:e112152. [PMID: 25386961 PMCID: PMC4227708 DOI: 10.1371/journal.pone.0112152] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Accepted: 10/13/2014] [Indexed: 11/29/2022] Open
Abstract
Of the multiple neurotransmitters and neuropeptides expressed in the mammalian taste bud, serotonin remains both the most studied and least understood. Serotonin is expressed in a subset of taste receptor cells that form synapses with afferent nerve fibers (type III cells) and was once thought to be essential to neurotransmission (now understood as purinergic). However, the discovery of the 5-HT1A serotonin receptor in a subset of taste receptor cells paracrine to type III cell suggested a role in cell-to-cell communication during the processing of taste information. Functional data describing this role are lacking. Using anatomical and neurophysiological techniques, this study proposes a modulatory role for serotonin during the processing of taste information. Double labeling immunocytochemical and single cell RT-PCR technique experiments documented that 5-HT1A-expressing cells co-expressed markers for type II cells, cells which express T1R or T2R receptors and release ATP. These cells did not co-express type III cells markers. Neurophysiological recordings from the chorda tympani nerve, which innervates anterior taste buds, were performed prior to and during intravenous injection of a 5-HT1A receptor antagonist. These experiments revealed that serotonin facilitates processing of taste information for tastants representing sweet, sour, salty, and bitter taste qualities. On the other hand, injection of ondansetron, a 5-HT3 receptor antagonist, was without effect. Collectively, these data support the hypothesis that serotonin is a crucial element in a finely-tuned feedback loop involving the 5-HT1A receptor, ATP, and purinoceptors. It is hypothesized that serotonin facilitates gustatory signals by regulating the release of ATP through ATP-release channels possibly through phosphatidylinositol 4,5-bisphosphate resynthesis. By doing so, 5-HT1A activation prevents desensitization of post-synaptic purinergic receptors expressed on afferent nerve fibers and enhances the afferent signal. Serotonin may thus play a major modulatory role within peripheral taste in shaping the afferent taste signals prior to their transmission across gustatory nerves.
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Affiliation(s)
- Luc Jaber
- College of Dentistry, The Ohio State University, Columbus, Ohio, United States of America
| | - Fang-li Zhao
- College of Dentistry, The Ohio State University, Columbus, Ohio, United States of America
| | - Tamara Kolli
- College of Dentistry, The Ohio State University, Columbus, Ohio, United States of America
| | - Scott Herness
- College of Dentistry, The Ohio State University, Columbus, Ohio, United States of America
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Duca FA, Swartz TD, Covasa M. Effect of diet on preference and intake of sucrose in obese prone and resistant rats. PLoS One 2014; 9:e111232. [PMID: 25329959 PMCID: PMC4203826 DOI: 10.1371/journal.pone.0111232] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Accepted: 09/29/2014] [Indexed: 01/03/2023] Open
Abstract
Increased orosensory stimulation from palatable diets and decreased feedback from gut signals have been proposed as contributing factors to obesity development. Whether altered taste functions associated with obesity are common traits or acquired deficits to environmental factors, such as a high-energy (HE)-diet, however, is not clear. To address this, we examined preference and sensitivity of increasing concentrations of sucrose solutions in rats prone (OP) and resistant (OR) to obesity during chow and HE feeding and measured lingual gene expression of the sweet taste receptor T1R3. When chow-fed, OP rats exhibited reduced preference and acceptance of dilute sucrose solutions, sham-fed less sucrose compared to OR rats, and had reduced lingual T1R3 gene expression. HE-feeding abrogated differences in sucrose preference and intake and lingual T1R3 expression between phenotypes. Despite similar sucrose intakes however, OP rats consumed significantly more total calories during 48-h two-bottle testing compared to OR rats. The results demonstrate that OP rats have an innate deficit for sweet taste detection, as illustrated by a reduction in sensitivity to sweets and reduced T1R3 gene expression; however their hyperphagia and subsequent obesity during HE-feeding is most likely not due to altered consumption of sweets.
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Affiliation(s)
- Frank A. Duca
- UMR 1319 MICALIS, Institut National de la Recherche Agronomique, Centre de Recherche de Jouy-, Jouy-en-Josas, France
- AgroParisTech, Jouy-en-Josas, France
| | - Timothy D. Swartz
- UMR 1319 MICALIS, Institut National de la Recherche Agronomique, Centre de Recherche de Jouy-, Jouy-en-Josas, France
- AgroParisTech, Jouy-en-Josas, France
| | - Mihai Covasa
- UMR 1319 MICALIS, Institut National de la Recherche Agronomique, Centre de Recherche de Jouy-, Jouy-en-Josas, France
- AgroParisTech, Jouy-en-Josas, France
- Department of Basic Medical Sciences, College of Osteopathic Medicine, Western University of Health Sciences, Pomona, California, United States of America
- Department of Human Health and Development, University of Suceava, Suceava, Romania
- * E-mail:
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Murovets VO, Bachmanov AA, Travnikov SV, Churikova AA, Zolotarev VA. The Involvement of the T1R3 Receptor Protein in the Control of Glucose Metabolism in Mice at Different Levels of Glycemia. J EVOL BIOCHEM PHYS+ 2014; 50:334-344. [PMID: 25983343 DOI: 10.1134/s0022093014040061] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The heterodimeric protein T1R2/T1R3 is a chemoreceptor mediating taste perception of sugars, several amino acids, and non-caloric sweeteners in humans and many other vertebrate species. The T1R2 and T1R3 proteins are expressed not only in the oral cavity, but also in the intestine, pancreas, liver, adipose tissue, and in structures of the central nervous system, which suggests their involvement in functions other than gustatory perception. In this study, we analyzed the role of the T1R3 protein in regulation of glucose metabolism in experiments with the gene-knockout mouse strain C57BL/6J-Tas1r3tm1Rfm (Tas1r3-/-), with a deletion of the Tas1r3 gene encoding T1R3, and the control strain C57BL/6ByJ with the intact gene. Glucose tolerance was measured in euglycemic or food-deprived mice after intraperitoneal or intragastric glucose administration. We have shown that in the Tas1r3-/- strain, in addition to the disappearance of taste preference for sucrose, glucose tolerance is also substantially reduced, and insulin resistance is observed. The effect of the Tas1r3 gene knockout on glucose utilization was more pronounced in the euglycemic state than after food deprivation. The baseline glucose level after food deprivation was lower in the Tas1r3-/- strain than in the control strain, which suggests that T1R3 is involved in regulation of endogenous glucose production. These data suggest that the T1R3-mediated glucoreception interacts with the KATP-dependent mechanisms of regulation of the glucose metabolism, and that the main role is likely played by T1R3 expressed in the pancreas and possibly in the central nervous system, but not in the intestinal mucosa, as it was suggested earlier.
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Affiliation(s)
- V O Murovets
- Pavlov Institute of Physiology, Russian Academy of Sciences, St. Petersburg, Russia
| | | | - S V Travnikov
- Pavlov Institute of Physiology, Russian Academy of Sciences, St. Petersburg, Russia
| | - A A Churikova
- Pavlov Institute of Physiology, Russian Academy of Sciences, St. Petersburg, Russia
| | - V A Zolotarev
- Pavlov Institute of Physiology, Russian Academy of Sciences, St. Petersburg, Russia
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Ohtsu Y, Nakagawa Y, Nagasawa M, Takeda S, Arakawa H, Kojima I. Diverse signaling systems activated by the sweet taste receptor in human GLP-1-secreting cells. Mol Cell Endocrinol 2014; 394:70-9. [PMID: 25017733 DOI: 10.1016/j.mce.2014.07.004] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Revised: 06/30/2014] [Accepted: 07/04/2014] [Indexed: 01/08/2023]
Abstract
Sweet taste receptor regulates GLP-1 secretion in enteroendocrine L-cells. We investigated the signaling system activated by this receptor using Hutu-80 cells. We stimulated them with sucralose, saccharin, acesulfame K and glycyrrhizin. These sweeteners stimulated GLP-1 secretion, which was attenuated by lactisole. All these sweeteners elevated cytoplasmic cyclic AMP ([cAMP]c) whereas only sucralose and saccharin induced a monophasic increase in cytoplasmic Ca(2+) ([Ca(2+)]c). Removal of extracellular calcium or sodium and addition of a Gq/11 inhibitor greatly reduced the [Ca(2+)]c responses to two sweeteners. In contrast, acesulfame K induced rapid and sustained reduction of [Ca(2+)]c. In addition, glycyrrhizin first reduced [Ca(2+)]c which was followed by an elevation of [Ca(2+)]c. Reductions of [Ca(2+)]c induced by acesulfame K and glycyrrhizin were attenuated by a calmodulin inhibitor or by knockdown of the plasma membrane calcium pump. These results indicate that various sweet molecules act as biased agonists and evoke strikingly different patterns of intracellular signals.
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Affiliation(s)
- Yoshiaki Ohtsu
- Institute for Molecular & Cellular Regulation, Gunma University, Maebashi 371-8512, Japan; Department of Pediatrics, Gunma University Graduate School of Medicine, Maebashi 371-8511, Japan
| | - Yuko Nakagawa
- Institute for Molecular & Cellular Regulation, Gunma University, Maebashi 371-8512, Japan
| | - Masahiro Nagasawa
- Institute for Molecular & Cellular Regulation, Gunma University, Maebashi 371-8512, Japan
| | - Shigeki Takeda
- Gunma University Graduate School of Technology, Kiryu 376-8515, Japan
| | - Hirokazu Arakawa
- Department of Pediatrics, Gunma University Graduate School of Medicine, Maebashi 371-8511, Japan
| | - Itaru Kojima
- Institute for Molecular & Cellular Regulation, Gunma University, Maebashi 371-8512, Japan.
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Simon BR, Learman BS, Parlee SD, Scheller EL, Mori H, Cawthorn WP, Ning X, Krishnan V, Ma YL, Tyrberg B, MacDougald OA. Sweet taste receptor deficient mice have decreased adiposity and increased bone mass. PLoS One 2014; 9:e86454. [PMID: 24466105 PMCID: PMC3899259 DOI: 10.1371/journal.pone.0086454] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Accepted: 12/10/2013] [Indexed: 12/16/2022] Open
Abstract
Functional expression of sweet taste receptors (T1R2 and T1R3) has been reported in numerous metabolic tissues, including the gut, pancreas, and, more recently, in adipose tissue. It has been suggested that sweet taste receptors in these non-gustatory tissues may play a role in systemic energy balance and metabolism. Smaller adipose depots have been reported in T1R3 knockout mice on a high carbohydrate diet, and sweet taste receptors have been reported to regulate adipogenesis in vitro. To assess the potential contribution of sweet taste receptors to adipose tissue biology, we investigated the adipose tissue phenotypes of T1R2 and T1R3 knockout mice. Here we provide data to demonstrate that when fed an obesogenic diet, both T1R2 and T1R3 knockout mice have reduced adiposity and smaller adipocytes. Although a mild glucose intolerance was observed with T1R3 deficiency, other metabolic variables analyzed were similar between genotypes. In addition, food intake, respiratory quotient, oxygen consumption, and physical activity were unchanged in T1R2 knockout mice. Although T1R2 deficiency did not affect adipocyte number in peripheral adipose depots, the number of bone marrow adipocytes is significantly reduced in these knockout animals. Finally, we present data demonstrating that T1R2 and T1R3 knockout mice have increased cortical bone mass and trabecular remodeling. This report identifies novel functions for sweet taste receptors in the regulation of adipose and bone biology, and suggests that in these contexts, T1R2 and T1R3 are either dependent on each other for activity or have common independent effects in vivo.
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Affiliation(s)
- Becky R. Simon
- Program in Cellular and Molecular Biology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Brian S. Learman
- Molecular & Integrative Physiology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Sebastian D. Parlee
- Molecular & Integrative Physiology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Erica L. Scheller
- Molecular & Integrative Physiology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Hiroyuki Mori
- Molecular & Integrative Physiology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - William P. Cawthorn
- Molecular & Integrative Physiology, University of Michigan, Ann Arbor, Michigan, United States of America
- Musculoskeletal Research, Lilly Research Laboratories, Indianapolis, Indiana, United States of America
| | - Xiaomin Ning
- Molecular & Integrative Physiology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Venkatesh Krishnan
- Musculoskeletal Research, Lilly Research Laboratories, Indianapolis, Indiana, United States of America
| | - Yanfei L. Ma
- Musculoskeletal Research, Lilly Research Laboratories, Indianapolis, Indiana, United States of America
| | - Björn Tyrberg
- Cardiovascular and Metabolic Disease, MedImmune LLC, Gaithersburg, Maryland, United States of America
- Diabetes and Obesity Research Center, Sanford-Burnham Medical Research Institute, Orlando, Florida, United States of America
| | - Ormond A. MacDougald
- Program in Cellular and Molecular Biology, University of Michigan, Ann Arbor, Michigan, United States of America
- Molecular & Integrative Physiology, University of Michigan, Ann Arbor, Michigan, United States of America
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, United States of America
- * E-mail:
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Wang R, van Keeken NMA, Siddiqui S, Dijksman LM, Maudsley S, Derval D, van Dam PS, Martin B. Higher TNF-α, IGF-1, and Leptin Levels are Found in Tasters than Non-Tasters. Front Endocrinol (Lausanne) 2014; 5:125. [PMID: 25120532 PMCID: PMC4114300 DOI: 10.3389/fendo.2014.00125] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Accepted: 07/11/2014] [Indexed: 12/03/2022] Open
Abstract
Taste perception is controlled by taste cells that are present in the tongue that produce and secrete various metabolic hormones. Recent studies have demonstrated that taste receptors in tongue, gut, and pancreas are associated with local hormone secretion. The aim of this study was to determine whether there is a link between taste sensitivity and levels of circulating metabolic hormones in humans and whether taste sensitivity is potentially related to peripheral metabolic regulation. Thirty-one subjects were recruited and separated into tasters and non-tasters based on their phenol thiocarbamide (PTC) bitter taste test results. Fasting plasma and saliva were collected and levels of hormones and cytokines were assayed. We observed significant differences in both hormone levels and hormone-body mass index (BMI) correlation between tasters and non-tasters. Tasters had higher plasma levels of leptin (p = 0.05), tumor necrosis factor-α (TNF-α) (p = 0.04), and insulin-like growth factor 1 (IGF-1) (p = 0.03). There was also a trend toward increased IGF-1 levels in the saliva of tasters (p = 0.06). We found a positive correlation between plasma levels of glucose and BMI (R = 0.4999, p = 0.04) exclusively in non-tasters. In contrast, plasma C-peptide levels were found to be positively correlated to BMI (R = 0.5563, p = 0.03) in tasters. Saliva TNF-α levels were negatively correlated with BMI in tasters (R = -0.5908, p = 0.03). Our findings demonstrate that there are differences in circulating levels of leptin, TNF-α, and IGF-1 between tasters and non-tasters. These findings indicate that in addition to the regulation of food consumption, taste perception also appears to be tightly linked to circulating metabolic hormone levels. People with different taste sensitivity may respond differently to the nutrient stimulation. Further work investigating the link between taste perception and peripheral metabolic control could potentially lead to the development of novel therapies for obesity or Type 2 diabetes.
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Affiliation(s)
- Rui Wang
- Metabolism Unit, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA
| | | | - Sana Siddiqui
- Receptor Pharmacology Unit, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA
| | - Lea M. Dijksman
- Teaching Hospital, Onze Lieve Vrouwe Gasthuis, Amsterdam, Netherlands
| | - Stuart Maudsley
- Receptor Pharmacology Unit, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA
- VIB Department of Molecular Genetics, University of Antwerp, Antwerp, Belgium
| | - Diana Derval
- Better Immune System Foundation, Amsterdam, Netherlands
| | - P. Sytze van Dam
- Department of Internal Medicine, Onze Lieve Vrouwe Gasthuis, Amsterdam, Netherlands
| | - Bronwen Martin
- Metabolism Unit, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA
- *Correspondence: Bronwen Martin, Metabolism Unit, National Institute on Aging, 251 Bayview Blvd., Suite 100 Room 08C009, Baltimore, MD 21224, USA e-mail:
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González-Abuín N, Martínez-Micaelo N, Blay M, Green BD, Pinent M, Ardévol A. Grape-seed procyanidins modulate cellular membrane potential and nutrient-induced GLP-1 secretion in STC-1 cells. Am J Physiol Cell Physiol 2013; 306:C485-92. [PMID: 24371039 DOI: 10.1152/ajpcell.00355.2013] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Grape-seed procyanidin extracts (GSPE) modulate glucose homeostasis, and it was suggested that GSPE may achieve this by enhancing the secretion of incretin hormones such as glucagon-like peptide-1 (GLP-1). Therefore, the aim of the present study is to examine in detail the effects of GSPE on intestinal endocrine cells (STC-1). GSPE was found to modulate plasma membrane potential in enteroendocrine cells, inducing depolarization at low concentrations (0.05 mg/l) and hyperpolarization at high concentrations (50 mg/l), and surprisingly this was also accompanied by suppressed GLP-1 secretion. Furthermore, how GSPE affects STC-1 cells under nutrient-stimulated conditions (i.e., glucose, linoleic acid, and l-proline) was also explored, and we found that the higher GSPE concentration was effective in limiting membrane depolarization and reducing GLP-1 secretion. Next, it was also examined whether GSPE affected mitochondrial membrane potential, and it was found that this too is altered by GSPE; however, this does not appear to explain the observed effects on plasma membrane potential and GLP-1 secretion. In conclusion, our results show that grape-seed procyanidins modulate cellular membrane potential and nutrient-induced enteroendocrine hormone secretion in STC-1 cells.
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Affiliation(s)
- Noemi González-Abuín
- Departament de Bioquímica i Biotecnologia, Universitat Rovira i Virgili, Tarragona, Spain; and
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50
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Abstract
Individual meals are products of a complex interaction of signals related to both short-term and long-term availability of energy stores. In addition to maintaining the metabolic demands of the individual in the short term, levels of energy intake must also maintain and defend body weight over longer periods. To accomplish this, satiety pathways are regulated by a sophisticated network of endocrine and neuroendocrine pathways. Higher brain centers modulate meal size through descending inputs to caudal brainstem regions responsible for the motor pattern generators associated with ingestion. Gastric and intestinal signals interact with central nervous system pathways to terminate food intake. These inputs can be modified as a function of internal metabolic signals, external environmental influences, and learning to regulate meal size.
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