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Gruber T, Lechner F, Krieger JP, García-Cáceres C. Neuroendocrine gut-brain signaling in obesity. Trends Endocrinol Metab 2024:S1043-2760(24)00120-6. [PMID: 38821753 DOI: 10.1016/j.tem.2024.05.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2024] [Revised: 04/29/2024] [Accepted: 05/03/2024] [Indexed: 06/02/2024]
Abstract
The past decades have witnessed the rise and fall of several, largely unsuccessful, therapeutic attempts to bring the escalating obesity pandemic to a halt. Looking back to look ahead, the field has now put its highest hopes in translating insights from how the gastrointestinal (GI) tract communicates with the brain to calibrate behavior, physiology, and metabolism. A major focus of this review is to summarize the latest advances in comprehending the neuroendocrine aspects of this so-called 'gut-brain axis' and to explore novel concepts, cutting-edge technologies, and recent paradigm-shifting experiments. These exciting insights continue to refine our understanding of gut-brain crosstalk and are poised to promote the development of additional therapeutic avenues at the dawn of a new era of antiobesity therapeutics.
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Affiliation(s)
- Tim Gruber
- Department of Metabolism and Nutritional Programming, Van Andel Institute, Grand Rapids, MI 49506, USA; Department of Epigenetics, Van Andel Institute, Grand Rapids, MI 49506, USA; German Center for Diabetes Research (DZD), 85764 Neuherberg, Germany.
| | - Franziska Lechner
- German Center for Diabetes Research (DZD), 85764 Neuherberg, Germany; Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), 85764 Neuherberg, Germany
| | - Jean-Philippe Krieger
- Institute of Veterinary Pharmacology and Toxicology, University of Zurich-Vetsuisse, 8057 Zurich, Switzerland; Institute of Neuroscience and Physiology, University of Gothenburg, 40530 Gothenburg, Sweden
| | - Cristina García-Cáceres
- German Center for Diabetes Research (DZD), 85764 Neuherberg, Germany; Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), 85764 Neuherberg, Germany; Medizinische Klinik und Poliklinik IV, Klinikum der Universität, Ludwig-Maximilians-Universität München, 80336 Munich, Germany.
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ADGRL3 genomic variation implicated in neurogenesis and ADHD links functional effects to the incretin polypeptide GIP. Sci Rep 2022; 12:15922. [PMID: 36151371 PMCID: PMC9508192 DOI: 10.1038/s41598-022-20343-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Accepted: 09/12/2022] [Indexed: 11/09/2022] Open
Abstract
Attention deficit/hyperactivity disorder (ADHD) is the most common childhood neurodevelopmental disorder. Single nucleotide polymorphisms (SNPs) in the Adhesion G Protein-Coupled Receptor L3 (ADGRL3) gene are associated with increased susceptibility to developing ADHD worldwide. However, the effect of ADGRL3 non-synonymous SNPs (nsSNPs) on the ADGRL3 protein function is vastly unknown. Using several bioinformatics tools to evaluate the impact of mutations, we found that nsSNPs rs35106420, rs61747658, and rs734644, previously reported to be associated and in linkage with ADHD in disparate populations from the world over, are predicted as pathogenic variants. Docking analysis of rs35106420, harbored in the ADGLR3-hormone receptor domain (HRM, a common extracellular domain of the secretin-like GPCRs family), showed that HRM interacts with the Glucose-dependent insulinotropic polypeptide (GIP), part of the incretin hormones family. GIP has been linked to the pathogenesis of diabetes mellitus, and our analyses suggest a potential link to ADHD. Overall, the comprehensive application of bioinformatics tools showed that functional mutations in the ADGLR3 gene disrupt the standard and wild ADGRL3 structure, most likely affecting its metabolic regulation. Further in vitro experiments are granted to evaluate these in silico predictions of the ADGRL3-GIP interaction and dissect the complexity underlying the development of ADHD.
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Signaling pathways in obesity: mechanisms and therapeutic interventions. Signal Transduct Target Ther 2022; 7:298. [PMID: 36031641 PMCID: PMC9420733 DOI: 10.1038/s41392-022-01149-x] [Citation(s) in RCA: 84] [Impact Index Per Article: 42.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Revised: 07/26/2022] [Accepted: 08/08/2022] [Indexed: 12/19/2022] Open
Abstract
Obesity is a complex, chronic disease and global public health challenge. Characterized by excessive fat accumulation in the body, obesity sharply increases the risk of several diseases, such as type 2 diabetes, cardiovascular disease, and nonalcoholic fatty liver disease, and is linked to lower life expectancy. Although lifestyle intervention (diet and exercise) has remarkable effects on weight management, achieving long-term success at weight loss is extremely challenging, and the prevalence of obesity continues to rise worldwide. Over the past decades, the pathophysiology of obesity has been extensively investigated, and an increasing number of signal transduction pathways have been implicated in obesity, making it possible to fight obesity in a more effective and precise way. In this review, we summarize recent advances in the pathogenesis of obesity from both experimental and clinical studies, focusing on signaling pathways and their roles in the regulation of food intake, glucose homeostasis, adipogenesis, thermogenesis, and chronic inflammation. We also discuss the current anti-obesity drugs, as well as weight loss compounds in clinical trials, that target these signals. The evolving knowledge of signaling transduction may shed light on the future direction of obesity research, as we move into a new era of precision medicine.
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Shi Y, Qin L, Wu M, Zheng J, Xie T, Shao Z. Gut neuroendocrine signaling regulates synaptic assembly in C. elegans. EMBO Rep 2022; 23:e53267. [PMID: 35748387 DOI: 10.15252/embr.202153267] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 05/26/2022] [Accepted: 06/01/2022] [Indexed: 11/09/2022] Open
Abstract
Synaptic connections are essential to build a functional brain. How synapses are formed during development is a fundamental question in neuroscience. Recent studies provided evidence that the gut plays an important role in neuronal development through processing signals derived from gut microbes or nutrients. Defects in gut-brain communication can lead to various neurological disorders. Although the roles of the gut in communicating signals from its internal environment to the brain are well known, it remains unclear whether the gut plays a genetically encoded role in neuronal development. Using C. elegans as a model, we uncover that a Wnt-endocrine signaling pathway in the gut regulates synaptic development in the brain. A canonical Wnt signaling pathway promotes synapse formation through regulating the expression of the neuropeptides encoding gene nlp-40 in the gut, which functions through the neuronally expressed GPCR/AEX-2 receptor during development. Wnt-NLP-40-AEX-2 signaling likely acts to modulate neuronal activity. Our study reveals a genetic role of the gut in synaptic development and identifies a novel contribution of the gut-brain axis.
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Affiliation(s)
- Yanjun Shi
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Department of Neurosurgery, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Lu Qin
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Department of Neurosurgery, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Mengting Wu
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Department of Neurosurgery, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Junyu Zheng
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Department of Neurosurgery, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Tao Xie
- Department of Neurosurgery, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Zhiyong Shao
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Department of Neurosurgery, Zhongshan Hospital, Fudan University, Shanghai, China
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Nagahisa T, Yamaguchi S, Kosugi S, Homma K, Miyashita K, Irie J, Yoshino J, Itoh H. Intestinal Epithelial NAD+ Biosynthesis Regulates GLP-1 Production and Postprandial Glucose Metabolism in Mice. Endocrinology 2022; 163:6537596. [PMID: 35218657 DOI: 10.1210/endocr/bqac023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Indexed: 11/19/2022]
Abstract
Obesity is associated with perturbations in incretin production and whole-body glucose metabolism, but the precise underlying mechanism remains unclear. Here, we tested the hypothesis that nicotinamide phosphoribosyltransferase (NAMPT), which mediates the biosynthesis of nicotinamide adenine dinucleotide (NAD+), a key regulator of cellular energy metabolism, plays a critical role in obesity-associated intestinal pathophysiology and systemic metabolic complications. To this end, we generated a novel mouse model, namely intestinal epithelial cell-specific Nampt knockout (INKO) mice. INKO mice displayed diminished glucagon-like peptide-1 (GLP-1) production, at least partly contributing to reduced early-phase insulin secretion and postprandial hyperglycemia. Mechanistically, loss of NAMPT attenuated the Wnt signaling pathway, resulting in insufficient GLP-1 production. We also found that diet-induced obese mice had compromised intestinal NAMPT-mediated NAD+ biosynthesis and Wnt signaling pathway, associated with impaired GLP-1 production and whole-body glucose metabolism, resembling the INKO mice. Finally, administration of a key NAD+ intermediate, nicotinamide mononucleotide (NMN), restored intestinal NAD+ levels and obesity-associated metabolic derangements, manifested by a decrease in ileal Proglucagon expression and GLP-1 production as well as postprandial hyperglycemia in INKO and diet-induced obese mice. Collectively, our study provides mechanistic and therapeutic insights into intestinal NAD+ biology related to obesity-associated dysregulation of GLP-1 production and postprandial hyperglycemia.
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Affiliation(s)
- Taichi Nagahisa
- Division of Endocrinology, Metabolism and Nephrology, Department of Internal Medicine, Keio University School of Medicine, Tokyo 160-8582, Japan
| | - Shintaro Yamaguchi
- Division of Endocrinology, Metabolism and Nephrology, Department of Internal Medicine, Keio University School of Medicine, Tokyo 160-8582, Japan
| | - Shotaro Kosugi
- Division of Endocrinology, Metabolism and Nephrology, Department of Internal Medicine, Keio University School of Medicine, Tokyo 160-8582, Japan
| | - Koichiro Homma
- Department of Emergency and Critical Care Medicine, Keio University School of Medicine, Shinjuku-ku, Tokyo 160-8582, Japan
| | - Kazutoshi Miyashita
- Division of Endocrinology, Metabolism and Nephrology, Department of Internal Medicine, Keio University School of Medicine, Tokyo 160-8582, Japan
| | - Junichiro Irie
- Division of Endocrinology, Metabolism and Nephrology, Department of Internal Medicine, Keio University School of Medicine, Tokyo 160-8582, Japan
- AMED-CREST, Japan Agency for Medical Research and Development, Chiyoda-ku, Tokyo 100-0004, Japan
| | - Jun Yoshino
- Division of Endocrinology, Metabolism and Nephrology, Department of Internal Medicine, Keio University School of Medicine, Tokyo 160-8582, Japan
- Center for Human Nutrition, Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Hiroshi Itoh
- Division of Endocrinology, Metabolism and Nephrology, Department of Internal Medicine, Keio University School of Medicine, Tokyo 160-8582, Japan
- AMED-CREST, Japan Agency for Medical Research and Development, Chiyoda-ku, Tokyo 100-0004, Japan
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Brexpiprazole caused glycolipid metabolic disorder by inhibiting GLP1/GLP1R signaling in rats. Acta Pharmacol Sin 2021; 42:1267-1279. [PMID: 33976388 PMCID: PMC8285380 DOI: 10.1038/s41401-021-00680-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Accepted: 04/10/2021] [Indexed: 02/02/2023] Open
Abstract
Brexpiprazole (Bre) is a new multi-target antipsychotic drug (APD) approved by the US FDA in 2015, and shows good therapeutic potential. But it lacks assessments on the metabolic side effects, which obstructs the treatment of schizophrenia. Glucagon-like peptide 1 (GLP1), an incretin associated with insulin action and metabolism, is involved in the metabolic syndrome (MS) caused by most APDs. In this study, we examined the adverse effects of Bre on glycolipid metabolism in rats and determined whether GLP1 was involved in Bre-caused MS. In the first part of experiments, rats were orally administered Bre (0.5 mg· kg-1· d-1) for 28 days with aripiprazole (1.0 mg· kg-1· d-1) or olanzapine (1.0 mg· kg-1· d-1) as the controls. Compared to vehicle, Bre administration significantly increased the weight gain, serum lipid (TG, TC, LDL, FFA), and blood glucose levels accompanied by the hormonal (insulin, glucagon, GLP1) imbalance, and the impaired glucose tolerance and insulin sensitivity. Moreover, we demonstrated that Bre administration significantly decreased the protein and mRNA levels of GLP1 in pancreas and small intestine by suppressing CaMKIIα, AMPK, and β-catenin; Bre administration also caused islet dysfunction with decreased GLP1R, PI3K, IRβ expression in pancreas, and the interference of IRS1, PI3K, p-AKT, and GLUT4 expression in the liver and skeletal muscle that represented the insulin resistance. In the second part of experiments, rats were orally administered Bre (0.5 mg· kg-1· d-1) for 42 days. We showed that co-administration with the GLP1 receptor (GLP1R) agonist liraglutide (0.125 mg· kg-1· d-1, ip) could ameliorate Bre-caused metabolic abnormalities. Our results demonstrate that GLP1/GLP1R signaling is involved in Bre-induced glycolipid metabolic disorders and co-treatment with liraglutide is an effective intervention against those abnormal metabolisms.
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Tian L, Shao W, Ip W, Song Z, Badakhshi Y, Jin T. The developmental Wnt signaling pathway effector β-catenin/TCF mediates hepatic functions of the sex hormone estradiol in regulating lipid metabolism. PLoS Biol 2019; 17:e3000444. [PMID: 31589598 PMCID: PMC6797220 DOI: 10.1371/journal.pbio.3000444] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Revised: 10/17/2019] [Accepted: 09/10/2019] [Indexed: 12/11/2022] Open
Abstract
The bipartite transcription factor β-catenin (β-cat)/T cell factor (TCF), formed by free β-cat and a given TCF family member, serves as the effector of the developmental Wnt signaling cascade. β-cat/TCFs also serve as effectors of certain peptide hormones or growth factors during adulthood. We reported that liver-specific expression of dominant-negative Transcription factor 7 like 2 (TCF7L2DN) led to impaired glucose disposal. Here we show that, in this LTCFDN transgenic mouse model, serum and hepatic lipid contents were elevated in male but not in female mice. In hepatocytes, TCF7L2DN adenovirus infection led to stimulated expression of genes that encode lipogenic transcription factors and lipogenic enzymes, while estradiol (E2) treatment attenuated the stimulation, associated with Wnt-target gene activation. Mechanistically, this E2-mediated activation can be attributed to elevated β-cat Ser675 phosphorylation and TCF expression. In wild-type female mice, ovariectomy (OVX) plus high-fat diet (HFD) challenge impaired glucose disposal and insulin tolerance, associated with increased hepatic lipogenic transcription factor sterol regulatory element-binding protein 1-c (SREBP-1c) expression. In wild-type mice with OVX, E2 reconstitution attenuated HFD-induced metabolic defects. Some of the attenuation effects, including insulin intolerance, elevated liver-weight gain, and hepatic SREBP-1c expression, were not affected by E2 reconstitution in HFD-fed LTCFDN mice with OVX. Finally, the effects of E2 in hepatocytes on β-cat/TCF activation can be attenuated by the G-protein-coupled estrogen receptor (GPER) antagonist G15. Our study thus expanded the scope of functions of the Wnt pathway effector β-cat/TCF, as it can also mediate hepatic functions of E2 during adulthood. This study also enriches our mechanistic understanding of gender differences in the risk and pathophysiology of metabolic diseases.
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Affiliation(s)
- Lili Tian
- Division of Advanced Diagnostics, Toronto General Hospital Research Institute, University Health Network, Toronto, Canada
- Department of Physiology, University of Toronto, Toronto, Canada
- Banting and Best Diabetes Center, Faculty of Medicine, University of Toronto, Toronto, Canada
| | - Weijuan Shao
- Division of Advanced Diagnostics, Toronto General Hospital Research Institute, University Health Network, Toronto, Canada
- Department of Physiology, University of Toronto, Toronto, Canada
- Banting and Best Diabetes Center, Faculty of Medicine, University of Toronto, Toronto, Canada
| | - Wilfred Ip
- Division of Advanced Diagnostics, Toronto General Hospital Research Institute, University Health Network, Toronto, Canada
| | - Zhuolun Song
- Division of Advanced Diagnostics, Toronto General Hospital Research Institute, University Health Network, Toronto, Canada
- Department of Physiology, University of Toronto, Toronto, Canada
- Banting and Best Diabetes Center, Faculty of Medicine, University of Toronto, Toronto, Canada
| | - Yasaman Badakhshi
- Division of Advanced Diagnostics, Toronto General Hospital Research Institute, University Health Network, Toronto, Canada
- Department of Physiology, University of Toronto, Toronto, Canada
- Banting and Best Diabetes Center, Faculty of Medicine, University of Toronto, Toronto, Canada
| | - Tianru Jin
- Division of Advanced Diagnostics, Toronto General Hospital Research Institute, University Health Network, Toronto, Canada
- Department of Physiology, University of Toronto, Toronto, Canada
- Banting and Best Diabetes Center, Faculty of Medicine, University of Toronto, Toronto, Canada
- * E-mail:
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Casanova-Martí À, Serrano J, Blay MT, Terra X, Ardévol A, Pinent M. Acute selective bioactivity of grape seed proanthocyanidins on enteroendocrine secretions in the gastrointestinal tract. Food Nutr Res 2017; 61:1321347. [PMID: 28659730 PMCID: PMC5475339 DOI: 10.1080/16546628.2017.1321347] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Accepted: 04/11/2017] [Indexed: 01/08/2023] Open
Abstract
Background: Enteroendocrine cells respond to food components by secreting an array of hormones that regulate several functions. We have previously shown that grape seed proanthocyanidins (GSPE) modulate GLP-1 levels. Objective: To deepen on the knowledge of the mechanisms used by GSPE to increase GLP-1, and extend it to its role at modulation of other enterohormones. Design: We used an ex vivo system to test direct modulation of enterohormones; STC-1 cells to test pure phenolic compounds; and rats to test the effects at different gastrointestinal segments. Results: GSPE compounds act at several locations along the gastrointestinal tract modulating enterohormone secretion depending on the feeding condition. GSPE directly promotes GLP-1 secretion in the ileum, while unabsorbed/metabolized forms do so in the colon. Such stimulation requires the presence of glucose. GSPE enhanced GIP and reduced CCK secretion; gallic acid could be partly responsible for this effect. Conclusions: The activity of GSPE modulating enterohormone secretion may help to explain its effects on metabolism. GSPE acts through several mechanisms; its compounds and their metabolites are GLP-1 secretagogues in ileum and colon, respectively. In vivo GLP-1 secretion might also be mediated by indirect pathways involving modulation of other enterohormones that in turn regulate GLP-1 release.
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Affiliation(s)
- Àngela Casanova-Martí
- MoBioFood Research Group. Departament de Bioquímica i Biotecnologia, Universitat Rovira i Virgili, Tarragona, Spain
| | - Joan Serrano
- MoBioFood Research Group. Departament de Bioquímica i Biotecnologia, Universitat Rovira i Virgili, Tarragona, Spain
| | - M Teresa Blay
- MoBioFood Research Group. Departament de Bioquímica i Biotecnologia, Universitat Rovira i Virgili, Tarragona, Spain
| | - Ximena Terra
- MoBioFood Research Group. Departament de Bioquímica i Biotecnologia, Universitat Rovira i Virgili, Tarragona, Spain
| | - Anna Ardévol
- MoBioFood Research Group. Departament de Bioquímica i Biotecnologia, Universitat Rovira i Virgili, Tarragona, Spain
| | - Montserrat Pinent
- MoBioFood Research Group. Departament de Bioquímica i Biotecnologia, Universitat Rovira i Virgili, Tarragona, Spain
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Mikosha AS, Kovzun OI, Tronko MD. Biological effects of lithium – fundamental and medical aspects. UKRAINIAN BIOCHEMICAL JOURNAL 2017. [DOI: 10.15407/ubj89.03.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
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10
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Abstract
The recent recognition of the clinical association between type 2 diabetes (T2D) and several types of human cancer has been further highlighted by reports of antidiabetic drugs treating or promoting cancer. At the cellular level, a plethora of molecules operating within distinct signaling pathways suggests cross-talk between the multiple pathways at the interface of the diabetes–cancer link. Additionally, a growing body of emerging evidence implicates homeostatic pathways that may become imbalanced during the pathogenesis of T2D or cancer or that become chronically deregulated by prolonged drug administration, leading to the development of cancer in diabetes and vice versa. This notion underscores the importance of combining clinical and basic mechanistic studies not only to unravel mechanisms of disease development but also to understand mechanisms of drug action. In turn, this may help the development of personalized strategies in which drug doses and administration durations are tailored to individual cases at different stages of the disease progression to achieve more efficacious treatments that undermine the diabetes–cancer association.
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Affiliation(s)
- Slavica Tudzarova
- Wolfson Institute for Biomedical Research, University College London, London WC1E6BT, UK
| | - Mahasin A Osman
- Department of Molecular Physiology, Pharmacology and Biotechnology, Division of Biology and Medicine, Warren Alpert Medical School, Brown University, Providence, RI 02912 Department of Chemistry and Forensic Sciences, College of Sciences and Technology, Savannah State University, Savannah, GA 41404
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Jin T. Current Understanding on Role of the Wnt Signaling Pathway Effector TCF7L2 in Glucose Homeostasis. Endocr Rev 2016; 37:254-77. [PMID: 27159876 DOI: 10.1210/er.2015-1146] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The role of the Wnt signaling pathway in metabolic homeostasis has drawn our intensive attention, especially after the genome-wide association study discovery that certain polymorphisms of its key effector TCF7L2 are strongly associated with the susceptibility to type 2 diabetes. For a decade, great efforts have been made in determining the function of TCF7L2 in various metabolic organs, which have generated both considerable achievements and disputes. In this review, I will briefly introduce the canonical Wnt signaling pathway, focusing on its effector β-catenin/TCF, including emphasizing the bidirectional feature of TCFs and β-catenin post-translational modifications. I will then summarize the observations on the association between TCF7L2 polymorphisms and type 2 diabetes risk. The main content, however, is on the intensive functional exploration of the metabolic role of TCF7L2, including the disputes generated on determining its role in the pancreas and liver with various transgenic mouse lines. Finally, I will discuss those achievements and disputes and present my future perspectives.
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Affiliation(s)
- Tianru Jin
- Division of Advanced Diagnostics, Toronto General Research Institute, University Health Network, Toronto, ON M5G 2C4, Canada
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12
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Zietek T, Rath E. Inflammation Meets Metabolic Disease: Gut Feeling Mediated by GLP-1. Front Immunol 2016; 7:154. [PMID: 27148273 PMCID: PMC4840214 DOI: 10.3389/fimmu.2016.00154] [Citation(s) in RCA: 85] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Accepted: 04/08/2016] [Indexed: 12/14/2022] Open
Abstract
Chronic diseases, such as obesity and diabetes, cardiovascular, and inflammatory bowel diseases (IBD) share common features in their pathology. Metabolic disorders exhibit strong inflammatory underpinnings and vice versa, inflammation is associated with metabolic alterations. Next to cytokines and cellular stress pathways, such as the unfolded protein response (UPR), alterations in the enteroendocrine system are intersections of various pathologies. Enteroendocrine cells (EEC) have been studied extensively for their ability to regulate gastrointestinal motility, secretion, and insulin release by release of peptide hormones. In particular, the L-cell-derived incretin hormone glucagon-like peptide 1 (GLP-1) has gained enormous attention due to its insulinotropic action and relevance in the treatment of type 2 diabetes (T2D). Yet, accumulating data indicate a critical role for EEC and in particular for GLP-1 in metabolic adaptation and in orchestrating immune responses beyond blood glucose control. EEC sense the lamina propria and luminal environment, including the microbiota via receptors and transporters. Subsequently, mediating signals by secreting hormones and cytokines, EEC can be considered as integrators of metabolic and inflammatory signaling. This review focuses on L cell and GLP-1 functions in the context of metabolic and inflammatory diseases. The effects of incretin-based therapies on metabolism and immune system are discussed and the interrelation and common features of metabolic and immune-mediated disorders are highlighted. Moreover, it presents data on the impact of inflammation, in particular of IBD on EEC and discusses the potential role of the microbiota as link between nutrients, metabolism, immunity, and disease.
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Affiliation(s)
- Tamara Zietek
- Department of Nutritional Physiology, Technische Universität München , Freising , Germany
| | - Eva Rath
- Chair of Nutrition and Immunology, Technische Universität München , Freising , Germany
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El-Salhy M, Mazzawi T, Hausken T, Hatlebakk JG. Interaction between diet and gastrointestinal endocrine cells. Biomed Rep 2016; 4:651-656. [PMID: 27284402 PMCID: PMC4887949 DOI: 10.3892/br.2016.649] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Accepted: 03/01/2016] [Indexed: 02/07/2023] Open
Abstract
The gastrointestinal endocrine cells are essential for life. They regulate the gastrointestinal motility, secretion, visceral sensitivity, absorption, local immune defense, cell proliferation and appetite. These cells act as sensory cells with specialized microvilli that project into the lumen that sense the gut contents (mostly nutrients and/or bacteria byproducts), and respond to luminal stimuli by releasing hormones into the lamina propria. These released hormones exert their actions by entering the circulating blood and reaching distant targets (endocrine mode), nearby structures (paracrine mode) or via afferent and efferent synaptic transmission. The mature intestinal endocrine cells are capable of expressing several hormones. A change in diet not only affects the release of gastrointestinal hormones, but also alters the densities of the gut endocrine cells. The interaction between ingested foodstuffs and the gastrointestinal endocrine cells can be utilized for the clinical management of gastrointestinal and metabolic diseases, such as irritable bowel syndrome, obesity and diabetes.
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Affiliation(s)
- Magdy El-Salhy
- Section for Gastroenterology, Department of Medicine, Stord Helse-Fonna Hospital, 5409 Stord, Norway; Section for Gastroenterology, Department of Clinical Medicine, University of Bergen, 5020 Bergen, Norway; Department of Medicine, National Centre for Functional Gastrointestinal Disorders, Haukeland University Hospital, 5021 Bergen, Norway
| | - Tarek Mazzawi
- Section for Gastroenterology, Department of Clinical Medicine, University of Bergen, 5020 Bergen, Norway; Department of Medicine, National Centre for Functional Gastrointestinal Disorders, Haukeland University Hospital, 5021 Bergen, Norway
| | - Trygve Hausken
- Section for Gastroenterology, Department of Clinical Medicine, University of Bergen, 5020 Bergen, Norway; Department of Medicine, National Centre for Functional Gastrointestinal Disorders, Haukeland University Hospital, 5021 Bergen, Norway
| | - Jan Gunnar Hatlebakk
- Section for Gastroenterology, Department of Clinical Medicine, University of Bergen, 5020 Bergen, Norway; Department of Medicine, National Centre for Functional Gastrointestinal Disorders, Haukeland University Hospital, 5021 Bergen, Norway
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14
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García-Martínez JM, Chocarro-Calvo A, De la Vieja A, García-Jiménez C. Insulin drives glucose-dependent insulinotropic peptide expression via glucose-dependent regulation of FoxO1 and LEF1/β-catenin. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2014; 1839:1141-50. [PMID: 25091498 DOI: 10.1016/j.bbagrm.2014.07.020] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2014] [Revised: 07/19/2014] [Accepted: 07/25/2014] [Indexed: 11/15/2022]
Abstract
Minutes after ingestion of fat or carbohydrates, vesicles stored in enteroendocrine cells release their content of incretin peptide hormones that, together with absorbed glucose, enhance insulin secretion by beta-pancreatic cells. Freshly-made incretins must therefore be packed into new vesicles in anticipation of the next meal with cells adjusting new incretin production to be proportional to the level of previous insulin release and absorbed blood glucose. Here we show that insulin stimulates the expression of the major human incretin, glucose-dependent insulinotropic peptide (GIP) in enteroendocrine cells but requires glucose to do it. Akt-dependent release of FoxO1 and glucose-dependent binding of LEF1/β-catenin mediate induction of Gip expression while insulin-induced phosphorylation of β-catenin does not alter its localization or transcriptional activity in enteroendocrine cells. Our results reveal a glucose-regulated feedback loop at the entero-insular axis, where glucose levels determine basal and insulin-induced Gip expression; GIP stimulation of insulin release, physiologically ensures a fine control of glucose homeostasis. How enteroendocrine cells adjust incretin production to replace incretin stores for future use is a key issue because GIP malfunction is linked to all forms of diabetes.
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Affiliation(s)
- Jose Manuel García-Martínez
- Department of Physiology, Biochemistry and Human Genetics, Faculty of Health Science, Rey Juan Carlos University, 28922 Alcorcon, Madrid, Spain
| | - Ana Chocarro-Calvo
- Department of Physiology, Biochemistry and Human Genetics, Faculty of Health Science, Rey Juan Carlos University, 28922 Alcorcon, Madrid, Spain
| | - Antonio De la Vieja
- Endocrine Tumor Unit (UFIEC), Instituto de Salud Carlos III, 28220 Majadahonda, Madrid, Spain
| | - Custodia García-Jiménez
- Department of Physiology, Biochemistry and Human Genetics, Faculty of Health Science, Rey Juan Carlos University, 28922 Alcorcon, Madrid, Spain.
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García-Jiménez C, García-Martínez JM, Chocarro-Calvo A, De la Vieja A. A new link between diabetes and cancer: enhanced WNT/β-catenin signaling by high glucose. J Mol Endocrinol 2014; 52:R51-66. [PMID: 24049067 DOI: 10.1530/jme-13-0152] [Citation(s) in RCA: 98] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Extensive epidemiological studies suggest that the diabetic population is at higher risk of site-specific cancers. The diabetes-cancer link has been hypothesized to rely on various hormonal (insulin, IGF1, adipokines), immunological (inflammation), or metabolic (hyperglycemia) characteristics of the disease and even on certain treatments. Inflammation may have an important but incompletely understood role. As a growth factor, insulin directly, or indirectly through IGF1, has been considered the major link between diabetes and cancer, while high glucose has been considered as a subordinate cause. Here we discuss the evidence that supports a role for insulin/IGF1 in general in cancer, and the mechanism by which hyperglycemia may enhance the appearance, growth and survival of diabetes-associated cancers. High glucose triggers several direct and indirect mechanisms that cooperate to promote cancer cell proliferation, migration, invasion and immunological escape. In particular, high glucose enhancement of WNT/β-catenin signaling in cancer cells promotes proliferation, survival and senescence bypass, and represents a previously unrecognized direct mechanism linking diabetes-associated hyperglycemia to cancer. Increased glucose uptake is a hallmark of tumor cells and may ensure enhanced WNT signaling for continuous proliferation. Mechanistically, high glucose unbalances acetylation through increased p300 acetyl transferase and decreased sirtuin 1 deacetylase activity, leading to β-catenin acetylation at lysine K354, a requirement for nuclear accumulation and transcriptional activation of WNT-target genes. The impact of high glucose on β-catenin illustrates the remodeling of cancer-associated signaling pathways by metabolites. Metabolic remodeling of cancer-associated signaling will receive much research attention in the coming years. Future epidemiological studies may be guided and complemented by the identification of these metabolic interplays. Together, these studies should lead to the development of new preventive strategies for diabetes-associated cancers.
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Affiliation(s)
- Custodia García-Jiménez
- Departamento de Fisiología y Bioquímica, Facultad de Ciencias de la Salud, Universidad Rey Juan Carlos, 28922 Alcorcon, Madrid, Spain Unidad Funcional de Investigación en Enfermedades Crónicas (UFIEC), Instituto de Salud Carlos III, 28220 Majadahonda, Madrid, Spain
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16
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Napoli N, Strollo R, Paladini A, Briganti SI, Pozzilli P, Epstein S. The alliance of mesenchymal stem cells, bone, and diabetes. Int J Endocrinol 2014; 2014:690783. [PMID: 25140176 PMCID: PMC4124651 DOI: 10.1155/2014/690783] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2013] [Accepted: 06/11/2014] [Indexed: 12/15/2022] Open
Abstract
Bone fragility has emerged as a new complication of diabetes. Several mechanisms in diabetes may influence bone homeostasis by impairing the action between osteoblasts, osteoclasts, and osteocytes and/or changing the structural properties of the bone tissue. Some of these mechanisms can potentially alter the fate of mesenchymal stem cells, the initial precursor of the osteoblast. In this review, we describe the main factors that impair bone health in diabetic patients and their clinical impact.
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Affiliation(s)
- Nicola Napoli
- Division of Endocrinology and Diabetes, Università Campus Bio-Medico di Roma, Via Alvaro del Portillo 21, 00128 Rome, Italy
- Division of Bone and Mineral Diseases, Washington University in St Louis, St Louis, MO, USA
- *Nicola Napoli:
| | - Rocky Strollo
- Division of Endocrinology and Diabetes, Università Campus Bio-Medico di Roma, Via Alvaro del Portillo 21, 00128 Rome, Italy
| | - Angela Paladini
- Division of Endocrinology and Diabetes, Università Campus Bio-Medico di Roma, Via Alvaro del Portillo 21, 00128 Rome, Italy
| | - Silvia I. Briganti
- Division of Endocrinology and Diabetes, Università Campus Bio-Medico di Roma, Via Alvaro del Portillo 21, 00128 Rome, Italy
| | - Paolo Pozzilli
- Division of Endocrinology and Diabetes, Università Campus Bio-Medico di Roma, Via Alvaro del Portillo 21, 00128 Rome, Italy
- Centre for Diabetes, The Blizard Building, Barts and The London School of Medicine, Queen Mary, University of London, London, UK
| | - Sol Epstein
- Division of Endocrinology, Mount Sinai School of Medicine, New York, USA
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Shao W, Wang Z, Ip W, Chiang YT, Xiong X, Chai T, Xu C, Wang Q, Jin T. GLP-1(28-36) improves β-cell mass and glucose disposal in streptozotocin-induced diabetic mice and activates cAMP/PKA/β-catenin signaling in β-cells in vitro. Am J Physiol Endocrinol Metab 2013; 304:E1263-72. [PMID: 23571712 DOI: 10.1152/ajpendo.00600.2012] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Recent studies have demonstrated that the COOH-terminal fragment of the incretin hormone glucagon-like peptide-1 (GLP-1), a nonapeptide GLP-1(28-36)amide, attenuates diabetes and hepatic steatosis in diet-induced obese mice. However, the effect of this nonapeptide in pancreatic β-cells remains largely unknown. Here, we show that in a streptozotocin-induced mouse diabetes model, GLP-1(28-36)amide improved glucose disposal and increased pancreatic β-cell mass and β-cell proliferation. An in vitro investigation revealed that GLP-1(28-36)amide stimulates β-catenin (β-cat) Ser(675) phosphorylation in both the clonal INS-1 cell line and rat primary pancreatic islet cells. In INS-1 cells, the stimulation was accompanied by increased nuclear β-cat content. GLP-1(28-36)amide was also shown to increase cellular cAMP levels, PKA enzymatic activity, and cAMP response element-binding protein (CREB) and cyclic AMP-dependent transcription factor-1 (ATF-1) phosphorylation. Furthermore, GLP-1(28-36)amide treatment enhanced islet insulin secretion and increased the growth of INS-1 cells, which was associated with increased cyclin D1 expression. Finally, PKA inhibition attenuated the effect of GLP-1(28-36)amide on β-cat Ser(675) phosphorylation and cyclin D1 expression in the INS-1 cell line. We have thus revealed the beneficial effect of GLP-1(28-36)amide in pancreatic β-cells in vitro and in vivo. Our observations suggest that GLP-1(28-36)amide may exert its effect through the PKA/β-catenin signaling pathway.
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Affiliation(s)
- Weijuan Shao
- Division of Advanced Diagnostics, Toronto General Research Institutes, University Health Network, Toronto, Ontario, Canada
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18
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Chocarro-Calvo A, García-Martínez J, Ardila-González S, De la Vieja A, García-Jiménez C. Glucose-Induced β-Catenin Acetylation Enhances Wnt Signaling in Cancer. Mol Cell 2013; 49:474-86. [DOI: 10.1016/j.molcel.2012.11.022] [Citation(s) in RCA: 105] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2012] [Revised: 10/23/2012] [Accepted: 11/20/2012] [Indexed: 12/13/2022]
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Chiang YA, Shao W, Xu XX, Chernoff J, Jin T. P21-activated protein kinase 1 (Pak1) mediates the cross talk between insulin and β-catenin on proglucagon gene expression and its ablation affects glucose homeostasis in male C57BL/6 mice. Endocrinology 2013. [PMID: 23183186 DOI: 10.1210/en.2012-1781] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
In gut endocrine L cells, the Wnt signaling pathway effector β-catenin (β-cat)/transcription factor 7-like 2 mediates the stimulatory effect of insulin on proglucagon (gcg) expression and glucagon-like peptide-1 (GLP-1) production. In several other cell lineages, insulin is able to stimulate p21-activated protein kinase 1 (Pak1). Here we determined the role of Pak1 in gcg expression and the effect of Pak1 deletion on glucose homeostasis. Insulin stimulated Pak1 activation through increasing its Thr423 phosphorylation in gut gcg-expressing cell lines, associated with increased gcg mRNA levels. This stimulation was attenuated by the Pak inhibitor 2,2'-dihydroxy-1,1'-dinaphthyldisulfide (IPA3) or dominant-negative Pak1. Both insulin and cAMP-promoting agents activated β-cat Ser675 phosphorylation, which was attenuated by IPA3 or protein kinase A inhibition, respectively. Gut gcg levels were reduced in male Pak1(-/-) mice, associated with impaired glucose tolerance after an ip or oral glucose challenge. These mice had lower circulating active GLP-1 levels after a glucose challenge as well as reduced distal ileum GLP-1 content after insulin treatment. Finally, the Pak1(-/-) mice exhibited reduced brainstem gcg level and abolished β-cat Ser675 phosphorylation in brain neurons after insulin treatment. We suggest that Pak1 mediates the cross talk between insulin and Wnt signaling pathways on gut and brain gcg expression, and its ablation impairs glucose homeostasis.
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Affiliation(s)
- Yuting Alex Chiang
- Departments of Physiology, University of Toronto, Ontario, Canada M5S 1A8
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Xiong X, Shao W, Jin T. New insight into the mechanisms underlying the function of the incretin hormone glucagon-like peptide-1 in pancreatic β-cells: the involvement of the Wnt signaling pathway effector β-catenin. Islets 2012; 4:359-65. [PMID: 23314611 PMCID: PMC3605164 DOI: 10.4161/isl.23345] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
During the past two decades, the exploration of function of two incretin hormones, namely glucagon-like peptide-1 (GLP-1) and gastric inhibitory peptide (GIP), has led to the development of two categories of novel therapeutic agents for diabetes and its complications, known as GLP-1 receptor (GLP-1R) agonists and DPP-IV inhibitors. Mechanisms underlying the function of GLP-1, however, still need to be further explored. GLP-1 not only functions as an incretin hormone in stimulating insulin secretion in response to nutritional, hormonal and neuronal stimulations, but also acts as an "insulin-like" factor in β-cell and extra-pancreatic organs. In addition to these insulinotropic and insulinomimetic effects, GLP-1 was shown to exert its protective effect in β-cell by repressing the expression of TxNIP, a mediator of glucolipotoxicity. A number of recent studies have shown that the Wnt signaling pathway effector, the bipartite transcription factor β-catenin/TCF, controls not only the production of GLP-1, but also the function of GLP-1. Furthermore, previously assumed "degradation" products of GLP-1(7-36)amide, including GLP-1(9-36)amide and GLP-1(28-36)amide, have been shown to exert beneficial effect in pancreas and extra-pancreatic tissues or cell lineages. Here we summarized our current knowledge on the metabolic, proliferative and protective effects of GLP-1(7-36)amide and its cleavage fragments, mainly focusing on pancreatic β-cells and the involvement of the Wnt signaling pathway effector β-catenin.
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Affiliation(s)
- Xiaoquan Xiong
- Department of Physiology; University of Toronto; Toronto, ON Canada
- Toronto General Research Institute, University Health Network; Toronto, ON Canada
| | - Weijuan Shao
- Department of Physiology; University of Toronto; Toronto, ON Canada
- Toronto General Research Institute, University Health Network; Toronto, ON Canada
| | - Tianru Jin
- Department of Physiology; University of Toronto; Toronto, ON Canada
- Institute of Medical Science; University of Toronto; Toronto, ON Canada
- Toronto General Research Institute, University Health Network; Toronto, ON Canada
- Correspondence to: Tianru Jin;
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Ip W, Chiang YTA, Jin T. The involvement of the wnt signaling pathway and TCF7L2 in diabetes mellitus: The current understanding, dispute, and perspective. Cell Biosci 2012; 2:28. [PMID: 22892353 PMCID: PMC3468386 DOI: 10.1186/2045-3701-2-28] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2012] [Accepted: 06/19/2012] [Indexed: 12/17/2022] Open
Abstract
The Wnt signaling pathway was initially discovered for its role in tumorigenesis and the development of Drosophila and other eukaryotic organisms. The key effector of this pathway, the bipartite transcription factor β-cat/TCF, is formed by free β-catenin (β-cat) and a TCF protein, including TCF7L2. Extensive recent investigations have highlighted the role of the Wnt signaling pathway in metabolic homeostasis and its implication in diabetes and other metabolic diseases. Genome-wide association studies have shown that several key components of the Wnt signaling pathway are implicated in metabolic homeostasis and the development of type 2 diabetes (T2D). Despite controversial observations regarding the role of Wnt signaling in the development and function of pancreatic islets, the discovery of the association between certain single nucleotide polymorphisms of TCF7L2 and T2D susceptibility has fueled great efforts to explore the role of Wnt signaling in the function of pancreatic β-cells and glucose homeostasis. Here we have introduced our basic understanding of the canonical Wnt signaling pathway, summarized our current knowledge on its implication in metabolic homeostasis and T2D, discussed the work on TCF7L2 as a T2D susceptibility gene, and presented the controversial role of Wnt signaling and TCF7L2 in pancreatic islets as well as their potential metabolic function in other organs. We then expanded our view into the crosstalk among Wnt, insulin and FOXO signaling cascades, which further illustrates the complexity of the Wnt signaling pathway in metabolic homeostasis. Finally, we have presented our perspectives.
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Affiliation(s)
- Wilfred Ip
- Institute of Medical Science, University of Toronto, Toronto, Canada.
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22
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Chiang YTA, Ip W, Jin T. The role of the Wnt signaling pathway in incretin hormone production and function. Front Physiol 2012; 3:273. [PMID: 22934027 PMCID: PMC3429047 DOI: 10.3389/fphys.2012.00273] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2012] [Accepted: 06/26/2012] [Indexed: 12/23/2022] Open
Abstract
Glucose metabolism is tightly controlled by multiple hormones and neurotransmitters in response to nutritional, environmental, and emotional changes. In addition to insulin and glucagon produced by pancreatic islets, two incretin hormones, namely glucagon-like peptide-1 (GLP-1) and gastric inhibitory polypeptide (GIP, also known as glucose-dependent insulinotropic peptide), also play important roles in blood glucose homeostasis. The incretin hormones mainly exert their regulatory effects via their corresponding receptors, which are expressed in pancreatic islets as well as many other extra-pancreatic organs. Recent studies have shown that the genes which encode these two incretin hormones can be regulated by the effectors of the Wnt signaling pathway, including TCF7L2, a transcription factor identified recently by extensive genome wide association studies as an important type 2 diabetes risk gene. Interestingly, TCF7L2 and β-catenin (β-cat), another effector of Wnt signaling pathway, may also mediate the function of the incretin hormones as well as the expression of their receptors in pancreatic β-cells. In this review, we have introduced the incretin hormones and the Wnt signaling pathway, summarized recent findings in the field, and provided our perspectives.
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Affiliation(s)
- Yu-Ting A Chiang
- Department of Physiology, University of Toronto Toronto, ON, Canada
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23
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Moran-Ramos S, Tovar AR, Torres N. Diet: friend or foe of enteroendocrine cells--how it interacts with enteroendocrine cells. Adv Nutr 2012; 3:8-20. [PMID: 22332097 PMCID: PMC3262619 DOI: 10.3945/an.111.000976] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Gut hormones play a key role in the regulation of food intake, energy expenditure, glucose homeostasis, lipid metabolism, and a wide range of metabolic functions in response to food ingestion. These hormones are altered in metabolic diseases, such as obesity and type 2 diabetes, and are thus proposed to be possible targets for the prevention or treatment of these diseases. It is clear that food composition, macronutrients, and other non-nutrient components as well as the physical properties of food not only modulate the secretion of gut peptides but also modulate transcription and enteroendocrine cell differentiation, which ultimately modifies gut hormone response. The specific mechanisms or sensing machinery that respond to the different components of the diet have been studied for many years; however, over the last few years, new molecular genetic techniques have led to important advances, thereby allowing a deeper understanding of these mechanisms. This review addresses the current knowledge regarding enteroendocrine cells and how diet interacts with this machinery to stimulate and regulate the secretion of gut peptides. The potential for diet interventions as a promising strategy for modulating gut hormone responses to food ingestion and, ultimately, preventing or treating metabolic diseases is being emphasized considering that these diseases are currently a public health burden.
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Affiliation(s)
- Sofia Moran-Ramos
- Departamento de Fisiología de la Nutrición Instituto Nacional de Ciencias Médicas y Nutrición “Salvador Zubirán,” México, México City, México; and,Facultad de Medicina, Universidad Nacional Autónoma de México, México City, México
| | - Armando R. Tovar
- Departamento de Fisiología de la Nutrición Instituto Nacional de Ciencias Médicas y Nutrición “Salvador Zubirán,” México, México City, México; and
| | - Nimbe Torres
- Departamento de Fisiología de la Nutrición Instituto Nacional de Ciencias Médicas y Nutrición “Salvador Zubirán,” México, México City, México; and,To whom correspondence should be addressed. E-mail:
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Paschetta E, Hvalryg M, Musso G. Glucose-dependent insulinotropic polypeptide: from pathophysiology to therapeutic opportunities in obesity-associated disorders. Obes Rev 2011; 12:813-28. [PMID: 21815989 DOI: 10.1111/j.1467-789x.2011.00897.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Glucose-dependent insulinotropic polypeptide (GIP) is a hormone secreted from the intestinal K-cells with established insulin-releasing actions. However, the GIP receptor is widely distributed in peripheral organs, including the adipose tissue, gut, bone and brain, where GIP modulates energy intake, cell metabolism and proliferation, and lipid and glucose metabolism, eventually promoting lipid and glucose storage. In diabetes and obesity, the incretin effect of GIP is blunted, while the extrapancreatic tissues keep a normal sensitivity to this hormone. As GIP levels are normal or elevated in obesity and diabetes, mounting evidence from chemical or genetic GIP deletion in animal models of obesity-related diabetes suggests that GIP may have a pro-obesogenic action and that a strategy antagonizing GIP action may be beneficial in these conditions, clearing triglyceride deposits from adipose tissue, liver and muscle, and restoring normal insulin sensitivity. Emerging evidence also suggests that the metabolic benefits of bypass surgery are mediated, at least in part, by surgical removal of GIP-secreting K-cells in the upper small intestine.
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Affiliation(s)
- E Paschetta
- Department of Internal Medicine, University of Turin, Turin, Italy Helgelandssykehu set, Mosjøen, Norway Gradenigo Hospital, Turin, Italy
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Gjesing AP, Kjems LL, Vestmar MA, Grarup N, Linneberg A, Deacon CF, Holst JJ, Pedersen O, Hansen T. Carriers of the TCF7L2 rs7903146 TT genotype have elevated levels of plasma glucose, serum proinsulin and plasma gastric inhibitory polypeptide (GIP) during a meal test. Diabetologia 2011; 54:103-10. [PMID: 20957343 DOI: 10.1007/s00125-010-1940-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/17/2010] [Accepted: 08/19/2010] [Indexed: 12/21/2022]
Abstract
AIMS/HYPOTHESIS The transcription factor 7-like 2 (TCF7L2) rs7903146 T allele associates with type 2 diabetes in several populations, possibly mediated via decreased incretin secretion and/or action and altered beta and alpha cell function. We aimed to study circulating levels of glucose, proinsulin, insulin, C-peptide, glucagon, glucagon-like peptide-1 (GLP-1), glucagon-like peptide-2 (GLP-2) and gastric inhibitory polypeptide (GIP) among individuals carrying the high-risk rs7903146 TT genotype and low-risk CC genotype following a meal test. METHODS A meal challenge was performed in 31 glucose-tolerant men (age 54 ± 7 years and BMI 26 ± 3 kg/m²) with rs7903146 TT genotype and 31 glucose-tolerant age- and BMI-matched men with CC genotype (age 53 ± 6 years and BMI 26 ± 3 kg/m²). Serum proinsulin, insulin, C-peptide and plasma glucose, glucagon, GLP-1, GLP-2 and GIP were obtained 0, 15, 30, 45, 60, 75, 90, 105, 120, 135, 150, 180, 210, and 240 min after ingestion of a standardised breakfast meal. RESULTS An elevated incremental AUC for plasma glucose was observed among TT genotype carriers (CC carriers 21.8 ± 101.9 mmol/l × min vs TT carriers 97.9 ± 89.2 mmol/l × min, p = 0.001). TT carriers also had increased AUCs for proinsulin (CC carriers 6,030 ± 3,001 pmol/l × min vs TT carriers 6,917 ± 4,820 pmol/l × min, p = 0.03), C-peptide (CC carriers 397.6 ± 131.9 nmol/l × min vs TT carriers 417.1 ± 109.3 nmol/l × min, p = 0.04) and GIP (CC carriers 12,310 ± 3,840 pmol/l × min vs TT carriers 14,590 ± 5,910 pmol/l × min, p = 0.004). CONCLUSIONS/INTERPRETATION Middle-aged normoglycaemic individuals carrying the rs7903146 TCF7L2 risk TT genotype show early signs of dysregulated glucose metabolism, decreased processing of proinsulin and elevated GIP secretion following a meal challenge.
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Affiliation(s)
- A P Gjesing
- Steno Diabetes Center, Hagedorn Research Institute, Gentofte, Denmark.
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Kim MH, Lee MK. The Incretins and Pancreatic beta-Cells: Use of Glucagon-Like Peptide-1 and Glucose-Dependent Insulinotropic Polypeptide to Cure Type 2 Diabetes Mellitus. KOREAN DIABETES JOURNAL 2010; 34:2-9. [PMID: 20532013 PMCID: PMC2879907 DOI: 10.4093/kdj.2010.34.1.2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Type 2 diabetes mellitus (T2DM) is increasing in prevalence worldwide. The complications associated with T2DM result in increased mortality and financial cost for those affected. T2DM has long been known to be associated with insulin resistance in peripheral tissues and a relative degree of insulin deficiency. However, the concept that insulin secretion and insulin sensitivity are not linked through a hyperbolic relationship in T2DM has continuously been demonstrated in many clinical trials. Thus, in order to prevent and treat T2DM, it is necessary to identify the substance(s) that will improve the function and survival of the pancreatic beta-cells in both normal and pathologic conditions, so that production and secretion of insulin can be enhanced. Incretin hormones, such as glucagon-like peptide (GLP)-1 and glucose-dependent insulinotropic polypeptide (GIP), have been shown to lower the postprandial and fasting glucose and the glycated hemoglobin levels, suppress the elevated glucagon level, and stimulate glucose-dependent insulin synthesis and secretion. In this report, we will review the biological actions and mechanisms associated with the actions of incretin hormones, GLP-1 and GIP, on beta-cell health and compare the differences between GLP-1 and GIP.
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Affiliation(s)
- Mi-Hyun Kim
- Division of Endocrinology and Metabolism, Samsung Biomedical Research Institute (SBRI), Seoul, Korea
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