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Guo T, Zhang H, Luo Y, Yang X, Wang L, Zhang G. Global Trends and Frontier in Research on Pancreatic Alpha Cells: A Bibliometric Analysis from 2013 to 2023. CLIN INVEST MED 2024; 47:23-39. [PMID: 38958477 DOI: 10.3138/cim-2024-2744] [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: 07/04/2024]
Abstract
PURPOSE Over the past 20 years, much of the research on diabetes has focused on pancreatic beta cells. In the last 10 years, interest in the important role of pancreatic alpha cells in the pathogenesis of diabetes, which had previously received little attention, has grown. We aimed to summarize and visualize the hotspot and development trends of pancreatic alpha cells through bibliometric analysis and to provide research direction and future ideas for the treatment of diabetes and other islet-related diseases. METHODS We used two scientometric software packages (CiteSpace 6.1.R6 and VOSviewer1.6.18) to visualize the information and connection of countries, institutions, authors, and keywords in this field. RESULTS A total of 532 publications, published in 752 institutions in 46 countries and regions, were included in this analysis. The United States showed the highest output, accounting for 39.3% of the total number of published papers. The most active institution was Vanderbilt University, and the authors with highest productivity came from Ulster University. In recent years, research hotspots have concentrated on transdifferentiation, gene expression, and GLP-1 regulatory function. Visualization analysis shows that research hotspots mainly focus on clinical diseases as well as physiological and pathological mechanisms and related biochemical indicators. CONCLUSIONS This study provides a review and summary of the literature on pancreatic alpha cells through bibliometric and visual methods and shows research hotspot and development trends, which can guide future directions for research.
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Affiliation(s)
- Teng Guo
- Department of Endocrinology, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China
- Graduate School, Beijing University of Chinese Medicine, Beijing, China
| | - Haoling Zhang
- Institute of Clinical Pharmacology, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Yunpeng Luo
- Department of Endocrinology, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China
- Graduate School, Beijing University of Chinese Medicine, Beijing, China
| | - Xi Yang
- Department of Endocrinology, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China
- Graduate School, Beijing University of Chinese Medicine, Beijing, China
| | - Lidan Wang
- Department of Endocrinology, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Guangde Zhang
- Department of Endocrinology, Xiyuan Hospital, China Academy of Chinese Medical Sciences, Beijing, China
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2
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Vivacqua G, Mancinelli R, Leone S, Vaccaro R, Garro L, Carotti S, Ceci L, Onori P, Pannarale L, Franchitto A, Gaudio E, Casini A. Endoplasmic reticulum stress: A possible connection between intestinal inflammation and neurodegenerative disorders. Neurogastroenterol Motil 2024; 36:e14780. [PMID: 38462652 DOI: 10.1111/nmo.14780] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Revised: 01/27/2024] [Accepted: 03/03/2024] [Indexed: 03/12/2024]
Abstract
BACKGROUND Different studies have shown the key role of endoplasmic reticulum (ER) stress in autoimmune and chronic inflammatory disorders, as well as in neurodegenerative diseases. ER stress leads to the formation of misfolded proteins which affect the secretion of different cell types that are crucial for the intestinal homeostasis. PURPOSE In this review, we discuss the role of ER stress and its involvement in the development of inflammatory bowel diseases, chronic conditions that can cause severe damage of the gastrointestinal tract, focusing on the alteration of Paneth cells and goblet cells (the principal secretory phenotypes of the intestinal epithelial cells). ER stress is also discussed in the context of neurodegenerative diseases, in which protein misfolding represents the signature mechanism. ER stress in the bowel and consequent accumulation of misfolded proteins might represent a bridge between bowel inflammation and neurodegeneration along the gut-to-brain axis, affecting intestinal epithelial homeostasis and the equilibrium of the commensal microbiota. Targeting intestinal ER stress could foster future studies for designing new biomarkers and new therapeutic approaches for neurodegenerative disorders.
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Affiliation(s)
- Giorgio Vivacqua
- Integrated Research Center (PRAAB), Campus Biomedico University of Roma, Rome, Italy
| | - Romina Mancinelli
- Department of Anatomical, Histological, Forensic Medicine and Orthopedic Sciences, Sapienza University of Rome, Rome, Italy
| | - Stefano Leone
- Department of Anatomical, Histological, Forensic Medicine and Orthopedic Sciences, Sapienza University of Rome, Rome, Italy
| | - Rosa Vaccaro
- Department of Anatomical, Histological, Forensic Medicine and Orthopedic Sciences, Sapienza University of Rome, Rome, Italy
| | - Ludovica Garro
- Department of Anatomical, Histological, Forensic Medicine and Orthopedic Sciences, Sapienza University of Rome, Rome, Italy
| | - Simone Carotti
- Integrated Research Center (PRAAB), Campus Biomedico University of Roma, Rome, Italy
| | - Ludovica Ceci
- Department of Anatomical, Histological, Forensic Medicine and Orthopedic Sciences, Sapienza University of Rome, Rome, Italy
| | - Paolo Onori
- Department of Anatomical, Histological, Forensic Medicine and Orthopedic Sciences, Sapienza University of Rome, Rome, Italy
| | - Luigi Pannarale
- Department of Anatomical, Histological, Forensic Medicine and Orthopedic Sciences, Sapienza University of Rome, Rome, Italy
| | - Antonio Franchitto
- Division of Health Sciences, Department of Movement, Human and Health Sciences, University of Rome 'Foro Italico', Rome, Italy
| | - Eugenio Gaudio
- Department of Anatomical, Histological, Forensic Medicine and Orthopedic Sciences, Sapienza University of Rome, Rome, Italy
| | - Arianna Casini
- Department of Anatomical, Histological, Forensic Medicine and Orthopedic Sciences, Sapienza University of Rome, Rome, Italy
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3
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Yuxuan A, Xiaoqin L, Songtao L, Jinmiao T, Xiaxia F, Kaili C, Lichao Z, Zhuoyu L. Polyphenols from whole millet grain (Setaria italica) alleviate glucose and lipid homeostasis in diet-induced obese mice by increasing endogenous GLP-1. JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE 2023; 103:7785-7797. [PMID: 37548615 DOI: 10.1002/jsfa.12901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2023] [Revised: 06/10/2023] [Accepted: 08/07/2023] [Indexed: 08/08/2023]
Abstract
BACKGROUND Foxtail millet (Setaria italica) is a whole millet grain that has been considered for improving the disorder of glucose and lipid metabolism. The purpose of the work is to explore the extraction and enrichment of polyphenols from foxtail millets which can regulate the disorder of glucose and lipid metabolism by increasing endogenous GLP-1 (glucagon-like peptide-1). RESULTS The optimum ultrasound-assisted extraction (UAE) of foxtail millet polyphenols (FMPs) was as follows: 70 °C and 400 W and 70% ethanol concentration, further purification using macroporous resin. In vitro, the FMP eluent of 60% ethanol (FMP-60) has the best effect in promoting GLP-1 secretion from L cells among the different active components of FMP. Millet polyphenols (MPs) were obtained from finishing foxtail millet with the bran removed by the same extraction and purification method. Compared with MP-60, FMP-60 mainly included eight active phenolic constituents and contained more ferulic acid, p-coumaric acid, 2-hydroxycinnamic acid, and coniferaldehyde. After gavage treatment of diet-induced obese (DIO) mice with FMP-60, FMP-60 promoted endogenous GLP-1 secretion in mice and ameliorated disorders of glucolipid metabolism in DIO mice. CONCLUSION FMP-60 could improve glucose homeostasis and ameliorates metabolic disease by promoting the endogenous GLP-1 level and preventing weight gain in DIO mice. © 2023 Society of Chemical Industry.
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Affiliation(s)
- An Yuxuan
- Institute of Biotechnology, The Key Laboratory of Chemical Biology and Molecular, Engineering of Ministry of Education, Shanxi University, Taiyuan, China
| | - La Xiaoqin
- Institutes of Biomedical Sciences, Shanxi University, Taiyuan, China
| | - Li Songtao
- Institute of Biotechnology, The Key Laboratory of Chemical Biology and Molecular, Engineering of Ministry of Education, Shanxi University, Taiyuan, China
| | - Tian Jinmiao
- Institute of Biotechnology, The Key Laboratory of Chemical Biology and Molecular, Engineering of Ministry of Education, Shanxi University, Taiyuan, China
| | - Fan Xiaxia
- Institute of Biotechnology, The Key Laboratory of Chemical Biology and Molecular, Engineering of Ministry of Education, Shanxi University, Taiyuan, China
| | - Cui Kaili
- Institute of Biotechnology, The Key Laboratory of Chemical Biology and Molecular, Engineering of Ministry of Education, Shanxi University, Taiyuan, China
| | - Zhang Lichao
- Institutes of Biomedical Sciences, Shanxi University, Taiyuan, China
| | - Li Zhuoyu
- Institute of Biotechnology, The Key Laboratory of Chemical Biology and Molecular, Engineering of Ministry of Education, Shanxi University, Taiyuan, China
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4
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Biancolin AD, Jeong H, Mak KWY, Yuan Z, Brubaker PL. Disrupted and Elevated Circadian Secretion of Glucagon-Like Peptide-1 in a Murine Model of Type 2 Diabetes. Endocrinology 2022; 163:6649564. [PMID: 35876276 PMCID: PMC9368029 DOI: 10.1210/endocr/bqac118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Indexed: 11/19/2022]
Abstract
Metabolism and circadian rhythms are intimately linked, with circadian glucagon-like peptide-1 (GLP-1) secretion by the intestinal L-cell entraining rhythmic insulin release. GLP-1 secretion has been explored in the context of obesogenic diets, but never in a rodent model of type 2 diabetes (T2D). There is also considerable disagreement regarding GLP-1 levels in human T2D. Furthermore, recent evidence has demonstrated decreased expression of the β-cell exocytotic protein secretagogin (SCGN) in T2D. To extend these findings to the L-cell, we administered oral glucose tolerance tests at 6 time points in 4-hour intervals to the high-fat diet/streptozotocin (HFD-STZ) mouse model of T2D. This revealed a 10-fold increase in peak GLP-1 secretion with a phase shift of the peak from the normal feeding period into the fasting-phase. This was accompanied by impairments in the rhythms of glucose, glucagon, mucosal clock genes (Arntl and Cry2), and Scgn. Immunostaining revealed that L-cell GLP-1 intensity was increased in the HFD-STZ model, as was the proportion of L-cells that expressed SCGN; however, this was not found in L-cells from humans with T2D, which exhibited decreased GLP-1 staining but maintained their SCGN expression. Gcg expression in isolated L-cells was increased along with pathways relating to GLP-1 secretion and electron transport chain activity in the HFD-STZ condition. Further investigation into the mechanisms responsible for this increase in GLP-1 secretion may give insights into therapies directed toward upregulating endogenous GLP-1 secretion.
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Affiliation(s)
- Andrew D Biancolin
- Departments of Physiology, University of Toronto, Toronto ON M5S 1A8, Canada
| | - Hyerin Jeong
- Departments of Physiology, University of Toronto, Toronto ON M5S 1A8, Canada
| | - Kimberly W Y Mak
- Departments of Physiology, University of Toronto, Toronto ON M5S 1A8, Canada
| | - Zixuan Yuan
- Departments of Physiology, University of Toronto, Toronto ON M5S 1A8, Canada
| | - Patricia L Brubaker
- Correspondence: Patricia L. Brubaker, Ph.D., Rm 3366 Medical Sciences Building, University of Toronto, 1 King’s College Circle, Toronto, ON M5S 1A8, Canada.
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5
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Filippello A, Di Mauro S, Scamporrino A, Torrisi SA, Leggio GM, Di Pino A, Scicali R, Di Marco M, Malaguarnera R, Purrello F, Piro S. Molecular Effects of Chronic Exposure to Palmitate in Intestinal Organoids: A New Model to Study Obesity and Diabetes. Int J Mol Sci 2022; 23:ijms23147751. [PMID: 35887100 PMCID: PMC9320247 DOI: 10.3390/ijms23147751] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Revised: 07/11/2022] [Accepted: 07/12/2022] [Indexed: 11/16/2022] Open
Abstract
Intestinal cell dysfunctions involved in obesity and associated diabetes could be correlated with impaired intestinal cell development. To date, the molecular mechanisms underlying these dysfunctions have been poorly investigated because of the lack of a good model for studying obesity. The main aim of this study was to investigate the effects of lipotoxicity on intestinal cell differentiation in small intestinal organoid platforms, which are used to analyze the regulation of cell differentiation. Mouse intestinal organoids were grown in the presence/absence of high palmitate concentrations (0.5 mM) for 48 h to simulate lipotoxicity. Palmitate treatment altered the expression of markers involved in the differentiation of enterocytes and goblet cells in the early (Hes1) and late (Muc2) phases of their development, respectively, and it modified enterocytes and goblet cell numbers. Furthermore, the expression of enteroendocrine cell progenitors (Ngn3) and I cells (CCK) markers was also impaired, as well as CCK-positive cell numbers and CCK secretion. Our data indicate, for the first time, that lipotoxicity simultaneously influences the differentiation of specific intestinal cell types in the gut: enterocytes, goblet cells and CCK cells. Through this study, we identified novel targets associated with molecular mechanisms affected by lipotoxicity that could be important for obesity and diabetes therapy.
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Affiliation(s)
- Agnese Filippello
- Department of Clinical and Experimental Medicine, Internal Medicine, Garibaldi-Nesima Hospital, University of Catania, 95122 Catania, Italy; (A.F.); (S.D.M.); (A.S.); (A.D.P.); (R.S.); (M.D.M.); (S.P.)
| | - Stefania Di Mauro
- Department of Clinical and Experimental Medicine, Internal Medicine, Garibaldi-Nesima Hospital, University of Catania, 95122 Catania, Italy; (A.F.); (S.D.M.); (A.S.); (A.D.P.); (R.S.); (M.D.M.); (S.P.)
| | - Alessandra Scamporrino
- Department of Clinical and Experimental Medicine, Internal Medicine, Garibaldi-Nesima Hospital, University of Catania, 95122 Catania, Italy; (A.F.); (S.D.M.); (A.S.); (A.D.P.); (R.S.); (M.D.M.); (S.P.)
| | - Sebastiano Alfio Torrisi
- Department of Biomedical and Biotechnological Sciences, University of Catania, Via S. Sofia, 64, 95123 Catania, Italy; (S.A.T.); (G.M.L.)
| | - Gian Marco Leggio
- Department of Biomedical and Biotechnological Sciences, University of Catania, Via S. Sofia, 64, 95123 Catania, Italy; (S.A.T.); (G.M.L.)
| | - Antonino Di Pino
- Department of Clinical and Experimental Medicine, Internal Medicine, Garibaldi-Nesima Hospital, University of Catania, 95122 Catania, Italy; (A.F.); (S.D.M.); (A.S.); (A.D.P.); (R.S.); (M.D.M.); (S.P.)
| | - Roberto Scicali
- Department of Clinical and Experimental Medicine, Internal Medicine, Garibaldi-Nesima Hospital, University of Catania, 95122 Catania, Italy; (A.F.); (S.D.M.); (A.S.); (A.D.P.); (R.S.); (M.D.M.); (S.P.)
| | - Maurizio Di Marco
- Department of Clinical and Experimental Medicine, Internal Medicine, Garibaldi-Nesima Hospital, University of Catania, 95122 Catania, Italy; (A.F.); (S.D.M.); (A.S.); (A.D.P.); (R.S.); (M.D.M.); (S.P.)
| | | | - Francesco Purrello
- Department of Clinical and Experimental Medicine, Internal Medicine, Garibaldi-Nesima Hospital, University of Catania, 95122 Catania, Italy; (A.F.); (S.D.M.); (A.S.); (A.D.P.); (R.S.); (M.D.M.); (S.P.)
- Correspondence: ; Tel.: +39-09-5759-8401
| | - Salvatore Piro
- Department of Clinical and Experimental Medicine, Internal Medicine, Garibaldi-Nesima Hospital, University of Catania, 95122 Catania, Italy; (A.F.); (S.D.M.); (A.S.); (A.D.P.); (R.S.); (M.D.M.); (S.P.)
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6
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Tanday N, English A, Lafferty RA, Flatt PR, Irwin N. Benefits of Sustained Upregulated Unimolecular GLP-1 and CCK Receptor Signalling in Obesity-Diabetes. Front Endocrinol (Lausanne) 2021; 12:674704. [PMID: 34054734 PMCID: PMC8160446 DOI: 10.3389/fendo.2021.674704] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Accepted: 04/29/2021] [Indexed: 12/11/2022] Open
Abstract
Combined activation of GLP-1 and CCK1 receptors has potential to synergistically augment the appetite-suppressive and glucose homeostatic actions of the individual parent peptides. In the current study, pancreatic beta-cell benefits of combined GLP-1 and CCK1 receptor upregulation were established, before characterising bioactivity and antidiabetic efficacy of an acylated dual-acting GLP-1/CCK hybrid peptide, namely [Lys12Pal]Ex-4/CCK. Both exendin-4 and CCK exhibited (p<0.001) proliferative and anti-apoptotic effects in BRIN BD11 beta-cells. Proliferative benefits were significantly (p<0.01) augmented by combined peptide treatment when compared to either parent peptide alone. These effects were linked to increases (p<0.001) in GLUT2 and glucokinase beta-cell gene expression, with decreased (p<0.05-p<0.001) expression of NFκB and BAX. [Lys12Pal]Ex-4/CCK exhibited prominent insulinotropic actions in vitro, coupled with beneficial (p<0.001) satiety and glucose homeostatic effects in the mice, with bioactivity evident 24 h after administration. Following twice daily injection of [Lys12Pal]Ex-4/CCK for 28 days in diabetic high fat fed (HFF) mice with streptozotocin (STZ)-induced compromised beta-cells, there were clear reductions (p<0.05-p<0.001) in energy intake and body weight. Circulating glucose was returned to lean control concentrations, with associated increases (p<0.001) in plasma and pancreatic insulin levels. Glucose tolerance and insulin secretory responsiveness were significantly (p<0.05-p<0.001) improved by hybrid peptide therapy. In keeping with this, evaluation of pancreatic histology revealed restoration of normal islet alpha- to beta-cell ratios and reduction (p<0.01) in centralised islet glucagon staining. Improvements in pancreatic islet morphology were associated with increased (p<0.05) proliferation and reduced (p<0.001) apoptosis of beta-cells. Together, these data highlight the effectiveness of sustained dual GLP-1 and CCK1 receptor activation by [Lys12Pal]Ex-4/CCK for the treatment of obesity-related diabetes.
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MESH Headings
- Animals
- Biomarkers/blood
- Blood Glucose/analysis
- Body Weight
- Diabetes Mellitus, Experimental/drug therapy
- Diabetes Mellitus, Experimental/metabolism
- Diabetes Mellitus, Experimental/pathology
- Diabetes Mellitus, Type 2/drug therapy
- Diabetes Mellitus, Type 2/metabolism
- Diabetes Mellitus, Type 2/pathology
- Diet, High-Fat
- Exenatide/pharmacology
- Glucagon-Like Peptide 1/genetics
- Glucagon-Like Peptide 1/metabolism
- Hypoglycemic Agents/pharmacology
- Insulin Secretion
- Insulin-Secreting Cells/drug effects
- Insulin-Secreting Cells/metabolism
- Insulin-Secreting Cells/pathology
- Male
- Mice
- Mice, Inbred C57BL
- Obesity/physiopathology
- Peptide Fragments/pharmacology
- Receptors, Cholecystokinin/genetics
- Receptors, Cholecystokinin/metabolism
- Up-Regulation
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7
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Nguyen-Tu MS, Martinez-Sanchez A, Leclerc I, Rutter GA, da Silva Xavier G. Adipocyte-specific deletion of Tcf7l2 induces dysregulated lipid metabolism and impairs glucose tolerance in mice. Diabetologia 2021; 64:129-141. [PMID: 33068125 PMCID: PMC7567653 DOI: 10.1007/s00125-020-05292-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Accepted: 08/07/2020] [Indexed: 12/11/2022]
Abstract
AIMS/HYPOTHESIS Transcription factor 7-like 2 (TCF7L2) is a downstream effector of the Wnt/β-catenin signalling pathway implicated in type 2 diabetes risk through genome-wide association studies. Although its expression is critical for adipocyte development, the potential roles of changes in adipose tissue TCF7L2 levels in diabetes risk are poorly defined. Here, we investigated whether forced changes in Tcf7l2 expression in adipocytes affect whole body glucose or lipid metabolism and crosstalk between disease-relevant tissues. METHODS Tcf7l2 was selectively ablated in mature adipocytes in C57BL/6J mice using Cre recombinase under Adipoq promoter control to recombine Tcf7l2 alleles floxed at exon 1 (referred to as aTCF7L2 mice). aTCF7L2 mice were fed normal chow or a high-fat diet for 12 weeks. Glucose and insulin sensitivity, as well as beta cell function, were assessed in vivo and in vitro. Levels of circulating NEFA, selected hormones and adipokines were measured using standard assays. RESULTS Reduced TCF7L2 expression in adipocytes altered glucose tolerance and insulin secretion in male but not in female mice. Thus, on a normal chow diet, male heterozygote knockout mice (aTCF7L2het) exhibited impaired glucose tolerance at 16 weeks (p = 0.03) and increased fat mass (1.4 ± 0.1-fold, p = 0.007) but no changes in insulin secretion. In contrast, male homozygote knockout (aTCF7L2hom) mice displayed normal body weight but impaired oral glucose tolerance at 16 weeks (p = 0.0001). These changes were mechanistically associated with impaired in vitro glucose-stimulated insulin secretion (decreased 0.5 ± 0.1-fold vs control mice, p = 0.02) and decreased levels of the incretins glucagon-like peptide-1 and glucose-dependent insulinotropic polypeptide (0.6 ± 0.1-fold and 0.4 ± 0.1-fold vs control mice, p = 0.04 and p < 0.0001, respectively). Circulating levels of plasma NEFA and fatty acid binding protein 4 were increased by 1.3 ± 0.1-fold and 1.8 ± 0.3-fold vs control mice (p = 0.03 and p = 0.05, respectively). Following exposure to a high-fat diet for 12 weeks, male aTCF7L2hom mice exhibited reduced in vivo glucose-stimulated insulin secretion (0.5 ± 0.1-fold vs control mice, p = 0.02). CONCLUSIONS/INTERPRETATION Loss of Tcf7l2 gene expression selectively in adipocytes leads to a sexually dimorphic phenotype, with impairments not only in adipocytes, but also in pancreatic islet and enteroendocrine cells in male mice only. Our findings suggest novel roles for adipokines and incretins in the effects of diabetes-associated variants in TCF7L2, and further illuminate the roles of TCF7L2 in glucose homeostasis and diabetes risk. Graphical abstract.
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Affiliation(s)
- Marie-Sophie Nguyen-Tu
- Section of Cell Biology and Functional Genomics, Department of Metabolism, Digestion and Reproduction, Hammersmith Hospital, Imperial College Centre for Translational and Experimental Medicine, London, UK
| | - Aida Martinez-Sanchez
- Section of Cell Biology and Functional Genomics, Department of Metabolism, Digestion and Reproduction, Hammersmith Hospital, Imperial College Centre for Translational and Experimental Medicine, London, UK
| | - Isabelle Leclerc
- Section of Cell Biology and Functional Genomics, Department of Metabolism, Digestion and Reproduction, Hammersmith Hospital, Imperial College Centre for Translational and Experimental Medicine, London, UK
| | - Guy A Rutter
- Section of Cell Biology and Functional Genomics, Department of Metabolism, Digestion and Reproduction, Hammersmith Hospital, Imperial College Centre for Translational and Experimental Medicine, London, UK.
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore.
| | - Gabriela da Silva Xavier
- Section of Cell Biology and Functional Genomics, Department of Metabolism, Digestion and Reproduction, Hammersmith Hospital, Imperial College Centre for Translational and Experimental Medicine, London, UK.
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, UK.
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8
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Sarnobat D, Moffett CR, Tanday N, Reimann F, Gribble FM, Flatt PR, Tarasov AI. Antidiabetic drug therapy alleviates type 1 diabetes in mice by promoting pancreatic α-cell transdifferentiation. Biochem Pharmacol 2020; 182:114216. [PMID: 32926875 PMCID: PMC7614179 DOI: 10.1016/j.bcp.2020.114216] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 09/03/2020] [Accepted: 09/04/2020] [Indexed: 12/17/2022]
Abstract
Gut incretins, glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic peptide (GIP), enhance secretion of insulin in a glucose-dependent manner, predominantly by elevating cytosolic levels of cAMP in pancreatic β-cells. Successful targeting of the incretin pathway by several drugs, however, suggests the antidiabetic mechanism is likely to span beyond the acute effect on hormone secretion and include, for instance, stimulation of β-cell growth and/or proliferation. Likewise, the antidiabetic action of kidney sodium-glucose linked transporter-2 (SGLT-2) inhibitors exceeds simple increase glucose excretion. Potential reasons for these 'added benefits' may lie in the long-term effects of these signals on developmental aspects of pancreatic islet cells. In this work, we explored if the incretin mimetics or SGLT-2 inhibitors can affect the size of the islet α- or β-cell compartments, under the condition of β-cell stress. To that end, we utilised mice expressing YFP specifically in pancreatic α-cells, in which we modelled type 1 diabetes by injecting streptozotocin, followed by a 10-day administration of liraglutide, sitagliptin or dapagliflozin. We observed an onset of diabetic phenotype, which was partially reversed by the administration of the antidiabetic drugs. The mechanism for the reversal included induction of β-cell proliferation, decrease in β-cell apoptosis and, for the incretin mimetics, transdifferentiation of α-cells into β-cells. Our data therefore emphasize the role of chronic incretin signalling in induction of α-/β-cell transdifferentiation. We conclude that incretin peptides may act directly on islet cells, making use of the endogenous local sites of 'ectopic' expression, whereas SGLT-2 inhibitors work via protecting β-cells from chronic hyperglycaemia.
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Affiliation(s)
- Dipak Sarnobat
- School of Biomedical Sciences, Ulster University, Cromore Road, Coleraine, BT52 1SA, UK
| | - Charlotte R Moffett
- School of Biomedical Sciences, Ulster University, Cromore Road, Coleraine, BT52 1SA, UK
| | - Neil Tanday
- School of Biomedical Sciences, Ulster University, Cromore Road, Coleraine, BT52 1SA, UK
| | - Frank Reimann
- Metabolic Research Laboratories, Wellcome Trust–MRC Institute of Metabolic Science, Addenbrooke’s Hospital, Cambridge, CB2 0QQ, UK
| | - Fiona M Gribble
- Metabolic Research Laboratories, Wellcome Trust–MRC Institute of Metabolic Science, Addenbrooke’s Hospital, Cambridge, CB2 0QQ, UK
| | - Peter R Flatt
- School of Biomedical Sciences, Ulster University, Cromore Road, Coleraine, BT52 1SA, UK
| | - Andrei I Tarasov
- School of Biomedical Sciences, Ulster University, Cromore Road, Coleraine BT52 1SA, UK.
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9
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The Protective Role of Hydrogen Sulfide Against Obesity-Associated Cellular Stress in Blood Glucose Regulation. Antioxidants (Basel) 2020; 9:antiox9111038. [PMID: 33114185 PMCID: PMC7690771 DOI: 10.3390/antiox9111038] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 10/16/2020] [Accepted: 10/20/2020] [Indexed: 12/13/2022] Open
Abstract
Circulating palmitic acid (PA) is increased in obesity and causes metabolic stress, leading to diabetes. This includes the impairment of the glucoregulatory hormone glucagon-like peptide-1 (GLP-1) secreted from intestinal L-cells. Recently, the anti-inflammatory gasotransmitter hydrogen sulfide (H2S) has been implicated in the enhancement of GLP-1 secretion. We hypothesized that H2S can reduce the oxidative stress caused by palmitate and play a protective role in L-cell function. This study was conducted on both human and mouse L-cells and a mouse model of Western diet (WD)-induced obesity. PA-induced L-cell stress was assessed using DCF-DA. H2S was delivered using the donor GYY4137. C57BL/6 mice were fed either chow diet or PA-enriched WD for 20 weeks with ongoing measurements of glycemia and GLP-1 secretion. In both L-cell models, we demonstrated that PA caused an increase in reactive oxygen species (ROS). This ROS induction was partially blocked by the H2S administration. In mice, the WD elevated body weight in both sexes and elevated fasting blood glucose and lipid peroxidation in males. Additionally, a single GYY4137 injection improved oral glucose tolerance in WD-fed male mice and also enhanced glucose-stimulated GLP-1 release. To conclude, H2S reduces oxidative stress in GLP-1 cells and can improve glucose clearance in mice.
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10
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Patibandla C, Khan ZI, MacGregor L, Campbell MJ, Patterson S. Costus pictus D. Don leaf extract stimulates GLP-1 secretion from GLUTag L-cells and has cytoprotective effects in BRIN-BD11 β-cells. JOURNAL OF ETHNOPHARMACOLOGY 2020; 260:112970. [PMID: 32422353 DOI: 10.1016/j.jep.2020.112970] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 05/07/2020] [Accepted: 05/08/2020] [Indexed: 06/11/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Costus pictus D. Don, commonly known as insulin plant, is a traditional Indian antidiabetic herbal medicine with glucose-lowering and insulin secretory effects having been reported in animal models and humans with Type 2 diabetes. However, its effects on GLP-1 secretion from intestinal endocrine L-cells and potential metabolic and protective effects in insulin secreting pancreatic β-cells are not yet fully understood. AIM OF THE STUDY This study is aimed to elucidate the effects of Costus pictus D. Don leaf extract (CPE) on L-cell function and GLP-1 secretion using the established murine GLUTag L-cell model and to investigate its potential cytoprotective effects against detrimental effects of palmitate and cytokines in pancreatic β-cells using BRIN-BD11 cells. METHODS Costus pictus D. Don dried leaf powder was extracted by soxhlet method. Cell viability was determined by MTT assay. Changes in gene and protein expression were quantified by qPCR and western blotting, respectively. GLP-1 and insulin secretion were measured by ELISA. RESULTS CPE significantly enhanced the percentage of viable BRIN-BD11 and GLUTag cells and protected BRIN-BD11 cells against palmitate- and proinflammatory cytokine-induced toxicity. CPE enhanced acute GLP-1 secretion 6.4-16.3-fold from GLUTag cells at both low (1.1 mM) and high (16.7 mM) glucose (P < 0.01) concentrations. Antioxidant (Nrf2, Cat & Gpx1) and pro-proliferative (Erk1 and Jnk1) gene expression were upregulated by 24 h culture with CPE, while proinflammatory transcription factor NF-κB was downregulated. CONCLUSION Diminished postprandial GLP-1 secretion and loss of insulin secreting β-cells are known contributors of T2DM. Our data suggests that CPE acutely stimulates GLP-1 secretion from L-cells. Long term exposure of the BRIN-BD11 cells to CPE enhances cell number and may protect against palmitate and proinflammatory cytokines by activating multiple pathways. Thus, the current study suggests that the possible antidiabetic properties of CPE may be linked to enhanced GLP-1 secretion and β-cell protection which could be beneficial in the management of T2DM.
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Affiliation(s)
- Chinmai Patibandla
- Department of Biological and Biomedical Sciences, School of Health and Life Sciences, Glasgow Caledonian University, Cowcaddens Road, Glasgow, G4 0BA, UK.
| | - Zahidul Islam Khan
- Department of Biological and Biomedical Sciences, School of Health and Life Sciences, Glasgow Caledonian University, Cowcaddens Road, Glasgow, G4 0BA, UK.
| | - Louise MacGregor
- Department of Biological and Biomedical Sciences, School of Health and Life Sciences, Glasgow Caledonian University, Cowcaddens Road, Glasgow, G4 0BA, UK.
| | - Mark James Campbell
- Department of Biological and Biomedical Sciences, School of Health and Life Sciences, Glasgow Caledonian University, Cowcaddens Road, Glasgow, G4 0BA, UK.
| | - Steven Patterson
- Department of Biological and Biomedical Sciences, School of Health and Life Sciences, Glasgow Caledonian University, Cowcaddens Road, Glasgow, G4 0BA, UK.
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11
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Xie Z, Jiang H, Liu W, Zhang X, Chen D, Sun S, Zhou C, Liu J, Bao S, Wang X, Zhang Y, Li J, Hu L, Li J. The triterpenoid sapogenin (2α-OH-Protopanoxadiol) ameliorates metabolic syndrome via the intestinal FXR/GLP-1 axis through gut microbiota remodelling. Cell Death Dis 2020; 11:770. [PMID: 32943612 PMCID: PMC7499306 DOI: 10.1038/s41419-020-02974-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2020] [Revised: 08/08/2020] [Accepted: 08/31/2020] [Indexed: 02/06/2023]
Abstract
Gypenosides, extracts of Gynostemma yixingense, have been traditionally prescribed to improve metabolic syndrome in Asian folk and local traditional medicine hospitals. However, the mechanism of its action remains unclarified. In this work, our results indicated that chronic administration of 2α-OH-protopanoxadiol (GP2), a metabolite of gypenosides in vivo, protected mice from high-fat diet-induced obesity and improved glucose tolerance by improving intestinal L-cell function. Mechanistically, GP2 treatment inhibited the enzymatic activity of bile salt hydrolase and modulated the proportions of the gut microbiota, which led to an increase in the accumulation of tauro-β-muricholic acid (TβMCA) in the intestine. TβMCA induced GLP-1 production and secretion by reducing the transcriptional activity of nuclear receptor farnesoid X receptor (FXR). Transplantation of GP2-remodelled fecal microbiota into antibiotic-treated mice also increased the intestinal TβMCA content and improved intestinal L-cell function. These findings demonstrate that GP2 ameliorates metabolic syndrome at least partly through the intestinal FXR/GLP-1 axis via gut microbiota remodelling and also suggest that GP2 may serve as a promising oral therapeutic agent for metabolic syndrome.
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Affiliation(s)
- Zhifu Xie
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, P.R. China
| | - Haowen Jiang
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, P.R. China
| | - Wei Liu
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, P.R. China.,University of Chinese Academy of Sciences, Beijing, 100864, P.R. China
| | - Xinwen Zhang
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, P.R. China
| | - Dakai Chen
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, P.R. China
| | - Shuimei Sun
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, P.R. China.,University of Chinese Academy of Sciences, Beijing, 100864, P.R. China
| | - Chendong Zhou
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, P.R. China
| | - Jia Liu
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, P.R. China
| | - Sheng Bao
- Jiangsu Key Laboratory for Functional Substance of Chinese Medicine, Nanjing University of Chinese Medicine, Nanjing, 210023, P.R. China
| | - Xiachang Wang
- Jiangsu Key Laboratory for Functional Substance of Chinese Medicine, Nanjing University of Chinese Medicine, Nanjing, 210023, P.R. China
| | - Yinan Zhang
- Jiangsu Key Laboratory for Functional Substance of Chinese Medicine, Nanjing University of Chinese Medicine, Nanjing, 210023, P.R. China
| | - Jia Li
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, P.R. China.,University of Chinese Academy of Sciences, Beijing, 100864, P.R. China
| | - Lihong Hu
- Jiangsu Key Laboratory for Functional Substance of Chinese Medicine, Nanjing University of Chinese Medicine, Nanjing, 210023, P.R. China.
| | - Jingya Li
- Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, P.R. China. .,University of Chinese Academy of Sciences, Beijing, 100864, P.R. China.
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12
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Sarnobat D, Moffett RC, Gault VA, Tanday N, Reimann F, Gribble FM, Flatt PR, Irwin N. Effects of long-acting GIP, xenin and oxyntomodulin peptide analogues on alpha-cell transdifferentiation in insulin-deficient diabetic Glu CreERT2;ROSA26-eYFP mice. Peptides 2020; 125:170205. [PMID: 31738969 PMCID: PMC7212078 DOI: 10.1016/j.peptides.2019.170205] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 11/08/2019] [Accepted: 11/13/2019] [Indexed: 02/08/2023]
Abstract
Enzyme-resistant long-acting forms of the gut-derived peptide hormones, glucose-dependent insulinotropic polypeptide (GIP), xenin and oxyntomodulin (Oxm) have been generated, and exert beneficial effects on diabetes control and pancreatic islet architecture. The current study has employed alpha-cell lineage tracing in GluCreERT2;ROSA26-eYFP transgenic mice to investigate the extent to which these positive pancreatic effects are associated with alpha- to beta-cell transdifferentiation. Twice-daily administration of (D-Ala2)GIP, xenin-25[Lys13PAL] or (D-Ser2)-Oxm[Lys38PAL] for 10 days to streptozotocin (STZ)-induced diabetic mice did not affect body weight, food intake or blood glucose levels, but (D-Ser2)-Oxm[Lys38PAL] reduced (P < 0.05 to P < 0.001) fluid intake and circulating glucagon. (D-Ala2)GIP and (D-Ser2)-Oxm[Lys38PAL] also augmented (P < 0.05 and P < 0.01, respectively) pancreatic insulin content. Detrimental changes of pancreatic morphology induced by STZ in GluCreERT2;ROSA26-eYFP mice were partially reversed by all treatment interventions. This was associated with reduced (P < 0.05) apoptosis and increased (P < 0.05 to P < 0.01) proliferation of beta-cells, alongside opposing effects on alpha-cells, with (D-Ala2)GIP and (D-Ser2)-Oxm[Lys38PAL] being particularly effective in this regard. Alpha-cell lineage tracing revealed that induction of diabetes was accompanied by increased (P < 0.01) transdifferentiation of glucagon positive alpha-cells to insulin positive beta-cells. This islet cell transitioning process was augmented (P < 0.01 and P < 0.001, respectively) by (D-Ala2)GIP and (D-Ser2)-Oxm[Lys38PAL]. (D-Ser2)-Oxm[Lys38PAL] also significantly (P < 0.05) promoted loss of alpha-cell identity in favour of other endocrine islet cells. These data highlight intra-islet benefits of (D-Ala2)GIP, xenin-25[Lys13PAL] and (D-Ser2)-Oxm[Lys38PAL] in diabetes with beta-cell loss induced by STZ. The effects appear to be independent of glycaemic change, and associated with alpha- to beta-cell transdifferentiation for the GIP and Oxm analogues.
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Affiliation(s)
- Dipak Sarnobat
- SAAD Centre for Pharmacy and Diabetes, Ulster University, Coleraine, Northern Ireland, UK
| | - R Charlotte Moffett
- SAAD Centre for Pharmacy and Diabetes, Ulster University, Coleraine, Northern Ireland, UK
| | - Victor A Gault
- SAAD Centre for Pharmacy and Diabetes, Ulster University, Coleraine, Northern Ireland, UK
| | - Neil Tanday
- SAAD Centre for Pharmacy and Diabetes, Ulster University, Coleraine, Northern Ireland, UK
| | - Frank Reimann
- Wellcome Trust-MRC Institute of Metabolic Science, University of Cambridge, Cambridge, UK
| | - Fiona M Gribble
- Wellcome Trust-MRC Institute of Metabolic Science, University of Cambridge, Cambridge, UK
| | - Peter R Flatt
- SAAD Centre for Pharmacy and Diabetes, Ulster University, Coleraine, Northern Ireland, UK
| | - Nigel Irwin
- SAAD Centre for Pharmacy and Diabetes, Ulster University, Coleraine, Northern Ireland, UK.
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13
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Mohan S, Moffett RC, Thomas KG, Irwin N, Flatt PR. Vasopressin receptors in islets enhance glucose tolerance, pancreatic beta-cell secretory function, proliferation and survival. Biochimie 2019; 158:191-198. [DOI: 10.1016/j.biochi.2019.01.008] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Accepted: 01/15/2019] [Indexed: 12/12/2022]
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14
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Guay C, Kruit JK, Rome S, Menoud V, Mulder NL, Jurdzinski A, Mancarella F, Sebastiani G, Donda A, Gonzalez BJ, Jandus C, Bouzakri K, Pinget M, Boitard C, Romero P, Dotta F, Regazzi R. Lymphocyte-Derived Exosomal MicroRNAs Promote Pancreatic β Cell Death and May Contribute to Type 1 Diabetes Development. Cell Metab 2019; 29:348-361.e6. [PMID: 30318337 DOI: 10.1016/j.cmet.2018.09.011] [Citation(s) in RCA: 171] [Impact Index Per Article: 34.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Revised: 07/20/2018] [Accepted: 09/12/2018] [Indexed: 12/13/2022]
Abstract
Type 1 diabetes is an autoimmune disease initiated by the invasion of pancreatic islets by immune cells that selectively kill the β cells. We found that rodent and human T lymphocytes release exosomes containing the microRNAs (miRNAs) miR-142-3p, miR-142-5p, and miR-155, which can be transferred in active form to β cells favoring apoptosis. Inactivation of these miRNAs in recipient β cells prevents exosome-mediated apoptosis and protects non-obese diabetic (NOD) mice from diabetes development. Islets from protected NOD mice display higher insulin levels, lower insulitis scores, and reduced inflammation. Looking at the mechanisms underlying exosome action, we found that T lymphocyte exosomes trigger apoptosis and the expression of genes involved in chemokine signaling, including Ccl2, Ccl7, and Cxcl10, exclusively in β cells. The induction of these genes may promote the recruitment of immune cells and exacerbate β cell death during the autoimmune attack. Our data point to exosomal-miRNA transfer as a communication mode between immune and insulin-secreting cells.
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Affiliation(s)
- Claudiane Guay
- Department of Fundamental Neurosciences, University of Lausanne, Rue du Bugnon 9, 1005 Lausanne, Switzerland
| | - Janine K Kruit
- Department of Pediatrics, Section Molecular Metabolism and Nutrition, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - Sophie Rome
- CarMeN Laboratory (INSERM 1060, INRA 1362, INSA), University of Lyon, Faculté de Médecine de Lyon Sud, Lyon, France
| | - Véronique Menoud
- Department of Fundamental Neurosciences, University of Lausanne, Rue du Bugnon 9, 1005 Lausanne, Switzerland
| | - Niels L Mulder
- Department of Pediatrics, Section Molecular Metabolism and Nutrition, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - Angelika Jurdzinski
- Department of Pediatrics, Section Molecular Metabolism and Nutrition, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands
| | - Francesca Mancarella
- Diabetes Unit, Department of Medicine, Surgery and Neurosciences, University of Siena, Siena, Italy; Umberto Di Mario ONLUS Foundation - Toscana Life Science Park, Siena, Italy
| | - Guido Sebastiani
- Diabetes Unit, Department of Medicine, Surgery and Neurosciences, University of Siena, Siena, Italy; Umberto Di Mario ONLUS Foundation - Toscana Life Science Park, Siena, Italy
| | - Alena Donda
- Ludwig Center for Cancer Research, University of Lausanne, Lausanne, Switzerland
| | - Bryan J Gonzalez
- Department of Fundamental Neurosciences, University of Lausanne, Rue du Bugnon 9, 1005 Lausanne, Switzerland
| | - Camilla Jandus
- Department of Oncology, CHUV, University of Lausanne, Lausanne, Switzerland
| | - Karim Bouzakri
- UMR DIATHEC, EA 7294, Centre Européen d'Etude du Diabète, Université de Strasbourg, Fédération de Médecine Translationnelle de Strasbourg, Strasbourg, France
| | - Michel Pinget
- UMR DIATHEC, EA 7294, Centre Européen d'Etude du Diabète, Université de Strasbourg, Fédération de Médecine Translationnelle de Strasbourg, Strasbourg, France
| | - Christian Boitard
- Institut National de Santé et de Recherche Médicale U1016, Paris, France; Université Paris Descartes, Sorbonne Paris Cité, Paris, France
| | - Pedro Romero
- Ludwig Center for Cancer Research, University of Lausanne, Lausanne, Switzerland
| | - Francesco Dotta
- Diabetes Unit, Department of Medicine, Surgery and Neurosciences, University of Siena, Siena, Italy; Umberto Di Mario ONLUS Foundation - Toscana Life Science Park, Siena, Italy
| | - Romano Regazzi
- Department of Fundamental Neurosciences, University of Lausanne, Rue du Bugnon 9, 1005 Lausanne, Switzerland.
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15
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Filippello A, Urbano F, Di Mauro S, Scamporrino A, Di Pino A, Scicali R, Rabuazzo AM, Purrello F, Piro S. Chronic Exposure to Palmitate Impairs Insulin Signaling in an Intestinal L-cell Line: A Possible Shift from GLP-1 to Glucagon Production. Int J Mol Sci 2018; 19:E3791. [PMID: 30487448 PMCID: PMC6321596 DOI: 10.3390/ijms19123791] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Revised: 11/21/2018] [Accepted: 11/24/2018] [Indexed: 12/11/2022] Open
Abstract
Obesity and type 2 diabetes mellitus (T2DM) are characterized by insulin resistance and impaired glucagon-like peptide-1 (GLP-1) secretion/function. Lipotoxicity, a chronic elevation of free fatty acids in the blood, could affect insulin-signaling in many peripheral tissues. To date, the effects of lipotoxicity on the insulin receptor and insulin resistance in the intestinal L-cells need to be elucidated. Moreover, recent observations indicate that L-cells may be able to process not only GLP-1 but also glucagon from proglucagon. The aim of this study was to investigate the effects of chronic palmitate exposure on insulin pathways, GLP-1 secretion and glucagon synthesis in the GLUTag L-cell line. Cells were cultured in the presence/absence of palmitate (0.5 mM) for 24 h to mimic lipotoxicity. Palmitate treatment affected insulin-stimulated GLP-1 secretion, insulin receptor phosphorylation and IRS-1-AKT pathway signaling. In our model lipotoxicity induced extracellular signal-regulated kinase (ERK 44/42) activation both in insulin stimulated and basal conditions and also up-regulated paired box 6 (PAX6) and proglucagon expression (Gcg). Interestingly, palmitate treatment caused an increased glucagon secretion through the up-regulation of prohormone convertase 2. These results indicate that a state of insulin resistance could be responsible for secretory alterations in L-cells through the impairment of insulin-signaling pathways. Our data support the hypothesis that lipotoxicity might contribute to L-cell deregulation.
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Affiliation(s)
- Agnese Filippello
- Department of Clinical and Experimental Medicine, Internal Medicine, Garibaldi-Nesima Hospital, University of Catania, 95122 Catania, Italy.
| | - Francesca Urbano
- Department of Clinical and Experimental Medicine, Internal Medicine, Garibaldi-Nesima Hospital, University of Catania, 95122 Catania, Italy.
| | - Stefania Di Mauro
- Department of Clinical and Experimental Medicine, Internal Medicine, Garibaldi-Nesima Hospital, University of Catania, 95122 Catania, Italy.
| | - Alessandra Scamporrino
- Department of Clinical and Experimental Medicine, Internal Medicine, Garibaldi-Nesima Hospital, University of Catania, 95122 Catania, Italy.
| | - Antonino Di Pino
- Department of Clinical and Experimental Medicine, Internal Medicine, Garibaldi-Nesima Hospital, University of Catania, 95122 Catania, Italy.
| | - Roberto Scicali
- Department of Clinical and Experimental Medicine, Internal Medicine, Garibaldi-Nesima Hospital, University of Catania, 95122 Catania, Italy.
| | - Agata Maria Rabuazzo
- Department of Clinical and Experimental Medicine, Internal Medicine, Garibaldi-Nesima Hospital, University of Catania, 95122 Catania, Italy.
| | - Francesco Purrello
- Department of Clinical and Experimental Medicine, Internal Medicine, Garibaldi-Nesima Hospital, University of Catania, 95122 Catania, Italy.
| | - Salvatore Piro
- Department of Clinical and Experimental Medicine, Internal Medicine, Garibaldi-Nesima Hospital, University of Catania, 95122 Catania, Italy.
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Liu P, Song J, Liu H, Yan F, He T, Wang L, Shen H, Hou X, Chen L. Insulin regulates glucagon-like peptide-1 secretion by pancreatic alpha cells. Endocrine 2018; 62:394-403. [PMID: 30084102 DOI: 10.1007/s12020-018-1684-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Accepted: 06/05/2018] [Indexed: 12/19/2022]
Abstract
PURPOSE Proglucagon is expressed in both pancreatic alpha cells and intestinal epithelial L cells and is cleaved into glucagon and glucagon-like peptide-1 (GLP-1) by different prohormone convertases (PCs). Recent studies have shown that α-cells can also secrete GLP-1, which may improve islet function. However, little is known about the factors influencing GLP-1 secretion by α cells. In this study, we investigated whether insulin promotes GLP-1 secretion by α cells, as well as the mechanisms underlying this phenomenon. METHODS We cultured the alpha-cell line In-R1-G9 in low- or high-glucose medium in the presence or absence of insulin to determine the influence of glucose concentrations on the actions of insulin. We also treated In-R1-G9 cells with insulin for different times and at different doses. Then GLP-1 and glucagon protein expression levels were estimated. Moreover, ERK and phosphatidylinositol-3-kinase/AKT (PI3K/AKT) pathway activity levels and prohormone convertase expression levels were evaluated to elucidate the mechanism underlying the effects of insulin on GLP-1 secretion by α-cells. RESULTS Insulin promoted GLP-1 secretion in a time- and dose-dependent manner under high-glucose conditions. Inhibiting the PI3K/AKT pathway with LY294002 and the Ras/mitogen-activated protein kinase (RAS/MAPK) pathway with PD98059 reduced GLP-1 secretion, respectively, in inhibitor-treated cells compared with insulin-treated cells. Moreover, insulin increased prohormone convertase 1/3 expression levels in the corresponding group of IN-R1-G9 cells compared with the control group of cells. CONCLUSION Insulin facilitates GLP-1 secretion by pancreatic alpha cells by inducing PC1/3 expression under high-glucose conditions, a phenomenon that may be associated mainly with PI3K/AKT pathway activation.
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Affiliation(s)
- Pan Liu
- Department of Endocrinology, Qilu Hospital of Shandong University, Jinan, 250000, China
- Institute of Endocrinology and Metabolism, Shandong University, Jinan, 250000, China
- Key Laboratory of Endocrinology and Metabolism, Shandong Province in Medicine & Health, Jinan, 250000, China
| | - Jia Song
- Department of Endocrinology, Qilu Hospital of Shandong University, Jinan, 250000, China
- Institute of Endocrinology and Metabolism, Shandong University, Jinan, 250000, China
- Key Laboratory of Endocrinology and Metabolism, Shandong Province in Medicine & Health, Jinan, 250000, China
| | - He Liu
- Department of Endocrinology, Qilu Hospital of Shandong University, Jinan, 250000, China
- Institute of Endocrinology and Metabolism, Shandong University, Jinan, 250000, China
- Key Laboratory of Endocrinology and Metabolism, Shandong Province in Medicine & Health, Jinan, 250000, China
| | - Fei Yan
- Department of Endocrinology, Qilu Hospital of Shandong University, Jinan, 250000, China
- Institute of Endocrinology and Metabolism, Shandong University, Jinan, 250000, China
- Key Laboratory of Endocrinology and Metabolism, Shandong Province in Medicine & Health, Jinan, 250000, China
| | - Tianyi He
- Department of Endocrinology, Qilu Hospital of Shandong University, Jinan, 250000, China
- Institute of Endocrinology and Metabolism, Shandong University, Jinan, 250000, China
- Key Laboratory of Endocrinology and Metabolism, Shandong Province in Medicine & Health, Jinan, 250000, China
| | - Lingshu Wang
- Department of Endocrinology, Qilu Hospital of Shandong University, Jinan, 250000, China
- Institute of Endocrinology and Metabolism, Shandong University, Jinan, 250000, China
- Key Laboratory of Endocrinology and Metabolism, Shandong Province in Medicine & Health, Jinan, 250000, China
| | - Huying Shen
- Baylor College of Medicine, Houston, TX, USA
| | - Xinguo Hou
- Department of Endocrinology, Qilu Hospital of Shandong University, Jinan, 250000, China.
- Institute of Endocrinology and Metabolism, Shandong University, Jinan, 250000, China.
- Key Laboratory of Endocrinology and Metabolism, Shandong Province in Medicine & Health, Jinan, 250000, China.
| | - Li Chen
- Department of Endocrinology, Qilu Hospital of Shandong University, Jinan, 250000, China.
- Institute of Endocrinology and Metabolism, Shandong University, Jinan, 250000, China.
- Key Laboratory of Endocrinology and Metabolism, Shandong Province in Medicine & Health, Jinan, 250000, China.
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17
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Wang D, Meng Q, Leech CA, Yepuri N, Zhang L, Holz GG, Wang C, Cooney RN. α7 Nicotinic Acetylcholine Receptor Regulates the Function and Viability of L Cells. Endocrinology 2018; 159:3132-3142. [PMID: 29992246 PMCID: PMC6456923 DOI: 10.1210/en.2018-00433] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Accepted: 07/02/2018] [Indexed: 12/20/2022]
Abstract
Enteroendocrine L cells secrete the incretin hormone glucagon-like peptide-1 (GLP-1), and they also express the α7 nicotinic acetylcholine receptor (α7nAChR), which may regulate GLP-1 secretion. Here, GTS-21, a selective α7nAChR agonist, was used to examine the effect of α7nAChR activation in L-cell lines, mouse intestinal primary cell cultures, and C57BL/6 mice. GTS-21 stimulated GLP-1 secretion in vitro, and this effect was attenuated by an α7nAChR antagonist or by α7nAChR-specific small interfering RNA. Under in vitro cell culture conditions of glucotoxicity, GTS-21 restored GLP-1 secretion and improved L-cell viability while also acting in vivo to raise levels of circulating GLP-1 in mice. To assess potential signaling mechanisms underlying these actions of GTS-21, we first monitored Ca2+, cAMP, and phosphatidylinositol 3-kinase (PI3K) activity. As expected for a GLP-1 secretagogue promoting Ca2+ influx through α7nAChR cation channels, [Ca2+]i increased in response to GTS-21, but [cAMP]i was unchanged. Surprisingly, pharmacological inhibition of growth factor signaling pathways revealed that GTS-21 also acts on the PI3K-protein kinase B-mammalian target of rapamycin pathway to promote L-cell viability. Moreover, the Ca2+ chelator BAPTA-AM counteracted GTS-21‒stimulated PI3K activity, thereby indicating unexpected crosstalk of L-cell Ca2+ and growth factor signaling pathways. Collectively, these data demonstrate that α7nAChR activation enhances GLP-1 secretion by increasing levels of cytosolic Ca2+ while also revealing Ca2+- and PI3K-dependent processes of α7nAChR activation that promote L-cell survival.
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Affiliation(s)
- Dawei Wang
- Department of Intensive Care Unit, Zhongnan Hospital of Wuhan University, Wuhan, Hubei, China
- Department of Surgery, SUNY Upstate Medical University, Syracuse, New York
| | - Qinghe Meng
- Department of Surgery, SUNY Upstate Medical University, Syracuse, New York
| | - Colin A Leech
- Department of Surgery, SUNY Upstate Medical University, Syracuse, New York
| | - Natesh Yepuri
- Department of Surgery, SUNY Upstate Medical University, Syracuse, New York
| | - Linlin Zhang
- Department of Surgery, SUNY Upstate Medical University, Syracuse, New York
| | - George G Holz
- Department of Medicine, SUNY Upstate Medical University, Syracuse, New York
- Department of Pharmacology, SUNY Upstate Medical University, Syracuse, New York
| | - Chunting Wang
- Department of Critical Care Medicine, Shandong Provincial Hospital, Shandong University, Jinan, Shandong Province, China
- Correspondence: Robert N. Cooney, MD, Department of Surgery, SUNY Upstate Medical University, 750 East Adams Street, Suite 8141, Syracuse, New York 13210. E-mail: ; or Chunting Wang, MD, Department of Critical Care Medicine, Shandong Provincial Hospital, Shandong University, 9677 Jing 10 Road, Jinan 250101, Shandong, China. E-mail:
| | - Robert N Cooney
- Department of Surgery, SUNY Upstate Medical University, Syracuse, New York
- Correspondence: Robert N. Cooney, MD, Department of Surgery, SUNY Upstate Medical University, 750 East Adams Street, Suite 8141, Syracuse, New York 13210. E-mail: ; or Chunting Wang, MD, Department of Critical Care Medicine, Shandong Provincial Hospital, Shandong University, 9677 Jing 10 Road, Jinan 250101, Shandong, China. E-mail:
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18
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Abstract
Type 1 diabetes is characterized by selective loss of beta cells and insulin secretion, which significantly impact glucose homeostasis. However, this progressive disease is also associated with dysfunction of the alpha cell component of the islet, which can exacerbate hyperglycemia due to paradoxical hyperglucagonemia or lead to severe hypoglycemia as a result of failed counterregulation. In this review, the physiology of alpha cell secretion and the potential mechanisms underlying alpha cell dysfunction in type 1 diabetes will be explored. Because type 1 diabetes is a progressive disease, a synthesized timeline of aberrant alpha cell function will be presented as an attempt to delineate the natural history of type 1 diabetes with respect to the alpha cell.
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Affiliation(s)
- Gina L C Yosten
- Department of Pharmacology and Physiology, Saint Louis University School of Medicine, 1402 S. Grand Blvd, Saint Louis, MO 63104, United States.
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19
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Lawlor N, Youn A, Kursawe R, Ucar D, Stitzel ML. Alpha TC1 and Beta-TC-6 genomic profiling uncovers both shared and distinct transcriptional regulatory features with their primary islet counterparts. Sci Rep 2017; 7:11959. [PMID: 28931935 PMCID: PMC5607285 DOI: 10.1038/s41598-017-12335-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Accepted: 09/06/2017] [Indexed: 01/09/2023] Open
Abstract
Alpha TC1 (αTC1) and Beta-TC-6 (βTC6) mouse islet cell lines are cellular models of islet (dys)function and type 2 diabetes (T2D). However, genomic characteristics of these cells, and their similarities to primary islet alpha and beta cells, are undefined. Here, we report the epigenomic (ATAC-seq) and transcriptomic (RNA-seq) landscapes of αTC1 and βTC6 cells. Each cell type exhibits hallmarks of its primary islet cell counterpart including cell-specific expression of beta (e.g., Pdx1) and alpha (e.g., Arx) cell transcription factors (TFs), and enrichment of binding motifs for these TFs in αTC1/βTC6 cis-regulatory elements. αTC1/βTC6 transcriptomes overlap significantly with the transcriptomes of primary mouse/human alpha and beta cells. Our data further indicate that ATAC-seq detects cell-specific regulatory elements for cell types comprising ≥ 20% of a mixed cell population. We identified αTC1/βTC6 cis-regulatory elements orthologous to those containing type 2 diabetes (T2D)-associated SNPs in human islets for 33 loci, suggesting these cells’ utility to dissect T2D molecular genetics in these regions. Together, these maps provide important insights into the conserved regulatory architecture between αTC1/βTC6 and primary islet cells that can be leveraged in functional (epi)genomic approaches to dissect the genetic and molecular factors controlling islet cell identity and function.
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Affiliation(s)
- Nathan Lawlor
- The Jackson Laboratory for Genomic Medicine, Farmington, CT, 06032, USA
| | - Ahrim Youn
- The Jackson Laboratory for Genomic Medicine, Farmington, CT, 06032, USA
| | - Romy Kursawe
- The Jackson Laboratory for Genomic Medicine, Farmington, CT, 06032, USA
| | - Duygu Ucar
- The Jackson Laboratory for Genomic Medicine, Farmington, CT, 06032, USA. .,Institute for Systems Genomics, University of Connecticut, Farmington, CT, 06032, USA. .,Department of Genetics & Genome Sciences, University of Connecticut, Farmington, CT, 06032, USA.
| | - Michael L Stitzel
- The Jackson Laboratory for Genomic Medicine, Farmington, CT, 06032, USA. .,Institute for Systems Genomics, University of Connecticut, Farmington, CT, 06032, USA. .,Department of Genetics & Genome Sciences, University of Connecticut, Farmington, CT, 06032, USA.
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20
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Kim MK, Shin HM, Jung H, Lee E, Kim TK, Kim TN, Kwon MJ, Lee SH, Rhee BD, Park JH. Comparison of pancreatic beta cells and alpha cells under hyperglycemia: Inverse coupling in pAkt-FoxO1. Diabetes Res Clin Pract 2017; 131:1-11. [PMID: 28666105 DOI: 10.1016/j.diabres.2017.05.017] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Revised: 05/04/2017] [Accepted: 05/16/2017] [Indexed: 01/09/2023]
Abstract
Type 2 diabetes manifests beta cell deficiencies and alpha cell expansion which is consistent with relative insulin deficiency and glucagon oversecretion. The effects of hyperglycemia on alpha cells are not as understood in comparison to beta cells. Hyperglycemia increases oxidative stress, which induces Akt activation or FoxO activation, depending on cell type. Several studies independently reported that FoxO1 translocations in alpha cells and beta cells were opposite. We compared the responses of pancreatic alpha cells and beta cells against hyperglycemia. Alpha TC-1 cells and Beta TC-6 cells were incubated with control (5mM Glucose) or high glucose (33mM Glucose) with or without PI3K inhibitor or FoxO1 inhibitor. We assessed PI3K, pAkt and phosphorylated FoxO1 (pFoxO1) in both cell lines. Immunostaining of BrdU and FoxO1 was detected by green fluorescence microscopy and confocal microscopy. Hyperglycemia and H2O2 decreased PI3K and pAKT in beta cells, but increased them in alpha cells. FoxO1 localizations and pFoxO1 expressions between alpha cells and beta cells were opposite. Proliferation of beta cells was decreased, but alpha cell proliferation was increased under hyperglycemia. Antioxidant enzymes including superoxide dismutase (SOD) and catalase were increased in beta cells and they were reversed with FoxO1 inhibitor treatment. Increased proliferation in alpha cells under hyperglycemia was attenuated with PI3K inhibitor. In conclusion, hyperglycemia increased alpha cell proliferation and glucagon contents which are opposite to beta cells. These differences may be related to contrasting PI3K/pAkt changes in both cells and subsequent FoxO1 modulation.
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Affiliation(s)
- Mi-Kyung Kim
- Division of Endocrinology and Metabolism, Department of Internal Medicine, College of Medicine, Inje University, Busan, South Korea; Paik Institute for Clinical Research, Molecular Therapy Lab, Inje University, Busan, South Korea.
| | - Hyun Mi Shin
- Paik Institute for Clinical Research, Molecular Therapy Lab, Inje University, Busan, South Korea
| | - HyeSook Jung
- Paik Institute for Clinical Research, Molecular Therapy Lab, Inje University, Busan, South Korea
| | - EunJu Lee
- Division of Endocrinology and Metabolism, Department of Internal Medicine, College of Medicine, Inje University, Busan, South Korea
| | - Tae Kyoon Kim
- Division of Endocrinology and Metabolism, Department of Internal Medicine, College of Medicine, Inje University, Busan, South Korea
| | - Tae Nyun Kim
- Division of Endocrinology and Metabolism, Department of Internal Medicine, College of Medicine, Inje University, Busan, South Korea
| | - Min Jeong Kwon
- Division of Endocrinology and Metabolism, Department of Internal Medicine, College of Medicine, Inje University, Busan, South Korea
| | - Soon Hee Lee
- Division of Endocrinology and Metabolism, Department of Internal Medicine, College of Medicine, Inje University, Busan, South Korea
| | - Byoung Doo Rhee
- Division of Endocrinology and Metabolism, Department of Internal Medicine, College of Medicine, Inje University, Busan, South Korea
| | - Jeong Hyun Park
- Division of Endocrinology and Metabolism, Department of Internal Medicine, College of Medicine, Inje University, Busan, South Korea; Paik Institute for Clinical Research, Molecular Therapy Lab, Inje University, Busan, South Korea
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21
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Glucotoxicity induces abnormal glucagon secretion through impaired insulin signaling in InR1G cells. PLoS One 2017; 12:e0176271. [PMID: 28426798 PMCID: PMC5398759 DOI: 10.1371/journal.pone.0176271] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Accepted: 04/07/2017] [Indexed: 11/19/2022] Open
Abstract
The significance of glucagon in the pathophysiology of diabetes mellitus is widely recognized, but the mechanisms underlying dysregulated glucagon secretion are still unclear. Here, we explored the molecular mechanisms of glucagon dysregulation, using an in vitro model. Hamster-derived glucagon-secreting InR1G cells were exposed to high glucose (25 mM) levels for 12 h before analyzing glucagon secretion and the activity of components involved in insulin signaling. High-glucose treatment induced increased glucagon secretion in InR1G cells, which represents a hallmark of diabetes mellitus. This treatment reduced the phosphorylation of Akt, indicating the deterioration of insulin signaling. Simultaneously, oxidative stress and JNK activity were shown to be increased. The inhibition of JNK signaling resulted in the amelioration of high-glucose level-induced glucagon secretion. Abnormally elevated glucagon secretion in diabetes can be reproduced by high-glucose treatment of InR1G cells, and the involvement of high glucose-oxidative stress-JNK-insulin signaling pathway axis has been demonstrated. These data elucidate, at least partly, the previously unclear mechanism of abnormal glucagon secretion, providing insights into a potential novel approach to diabetes treatment, targeting glucagon.
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22
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Asghar ZA, Cusumano A, Yan Z, Remedi MS, Moley KH. Reduced islet function contributes to impaired glucose homeostasis in fructose-fed mice. Am J Physiol Endocrinol Metab 2017; 312:E109-E116. [PMID: 28028036 PMCID: PMC5336566 DOI: 10.1152/ajpendo.00279.2016] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Revised: 12/19/2016] [Accepted: 12/19/2016] [Indexed: 01/09/2023]
Abstract
Increased sugar consumption, particularly fructose, in the form of sweetened beverages and sweeteners in our diet adversely affects metabolic health. Because these effects are associated with features of the metabolic syndrome in humans, the direct effect of fructose on pancreatic islet function is unknown. Therefore, we examined the islet phenotype of mice fed excess fructose. Fructose-fed mice exhibited fasting hyperglycemia and glucose intolerance but not hyperinsulinemia, dyslipidemia, or hyperuricemia. Islet function was impaired, with decreased glucose-stimulated insulin secretion and increased glucagon secretion and high fructose consumption leading to α-cell proliferation and upregulation of the fructose transporter GLUT5, which was localized only in α-cells. Our studies demonstrate that excess fructose consumption contributes to hyperglycemia by affecting both β- and α-cells of islets in mice.
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Affiliation(s)
- Zeenat A Asghar
- Department of Obstetrics and Gynecology, Washington University in St. Louis School of Medicine, St. Louis, Missouri; and
| | - Andrew Cusumano
- Department of Obstetrics and Gynecology, Washington University in St. Louis School of Medicine, St. Louis, Missouri; and
| | - Zihan Yan
- Department of Medicine, Washington University in St. Louis School of Medicine, St. Louis, Missouri
| | - Maria S Remedi
- Department of Medicine, Washington University in St. Louis School of Medicine, St. Louis, Missouri
| | - Kelle H Moley
- Department of Obstetrics and Gynecology, Washington University in St. Louis School of Medicine, St. Louis, Missouri; and
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23
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Fu J, Cui Q, Yang B, Hou Y, Wang H, Xu Y, Wang D, Zhang Q, Pi J. The impairment of glucose-stimulated insulin secretion in pancreatic β-cells caused by prolonged glucotoxicity and lipotoxicity is associated with elevated adaptive antioxidant response. Food Chem Toxicol 2016; 100:161-167. [PMID: 28027979 DOI: 10.1016/j.fct.2016.12.016] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Revised: 12/06/2016] [Accepted: 12/14/2016] [Indexed: 11/17/2022]
Abstract
Type 2 diabetes (T2D) is a progressive disease characterized by sustained hyperglycemia and is frequently accompanied by hyperlipidemia. Deterioration of β-cell function in T2D patients may be caused, in part, by long-term exposure to high concentrations of glucose and/or lipids. We developed systems to study how chronic glucotoxicity and lipotoxicity might be linked to the impairment of glucose-stimulated insulin secretion (GSIS) machinery in pancreatic β-cells. INS-1 (832/13) were exposed to glucose and/or palmitate for up to 10 weeks. Chronic high glucose and/or palmitate exposure resulted in impaired GSIS accompanied by a dramatic increase in oxidative stress, as determined by basal intracellular peroxide levels. In addition, the GSIS-associated reactive oxygen species (ROS) signals, assessed as glucose-stimulated peroxide accumulation positively correlated with GSIS in glucose- and/or palmitate-exposed cells, as well as glucose-stimulated reductions in GSH/GSSG ratios. Furthermore, the impairment of GSIS caused by chronic high glucose and/or palmitate exposures were attributed to the induction of adaptive antioxidant response and mitochondrial uncoupling, which negatively regulates glucose-derived ROS generation. Taken together, persistent glucotoxicity- and/or lipotoxicity-mediated oxidative stress and subsequent adaptive antioxidant response impair glucose-derived ROS signaling and GSIS in pancreatic β-cells.
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Affiliation(s)
- Jingqi Fu
- Program of Environmental Toxicology, School of Public Health, China Medical University No 77 Puhe Road, Shenyang North New Area, Shenyang, Liaoning, 110122, PR China
| | - Qi Cui
- Program of Environmental Toxicology, School of Public Health, China Medical University No 77 Puhe Road, Shenyang North New Area, Shenyang, Liaoning, 110122, PR China
| | - Bei Yang
- Department of Histology and Embryology, School of Basic Medical Sciences, China Medical University No 77 Puhe Road, Shenyang North New Area, Shenyang, Liaoning, 110122, PR China
| | - Yongyong Hou
- Program of Environmental Toxicology, School of Public Health, China Medical University No 77 Puhe Road, Shenyang North New Area, Shenyang, Liaoning, 110122, PR China
| | - Huihui Wang
- Program of Environmental Toxicology, School of Public Health, China Medical University No 77 Puhe Road, Shenyang North New Area, Shenyang, Liaoning, 110122, PR China
| | - Yuanyuan Xu
- Program of Environmental Toxicology, School of Public Health, China Medical University No 77 Puhe Road, Shenyang North New Area, Shenyang, Liaoning, 110122, PR China
| | - Difei Wang
- The First Affiliated Hospital, China Medical University, 155 Nanjingbei Street, Heping District, Shenyang, Liaoning, 110001, PR China
| | - Qiang Zhang
- Department of Environmental Health, Rollins School of Public Health, Emory University, 201 Dowman Drive, Atlanta, GA, 30322, USA
| | - Jingbo Pi
- Program of Environmental Toxicology, School of Public Health, China Medical University No 77 Puhe Road, Shenyang North New Area, Shenyang, Liaoning, 110122, PR China.
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24
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Green AD, Vasu S, Moffett RC, Flatt PR. Co-culture of clonal beta cells with GLP-1 and glucagon-secreting cell line impacts on beta cell insulin secretion, proliferation and susceptibility to cytotoxins. Biochimie 2016; 125:119-25. [DOI: 10.1016/j.biochi.2016.03.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Accepted: 03/21/2016] [Indexed: 12/22/2022]
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25
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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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26
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Urbano F, Filippello A, Di Pino A, Barbagallo D, Di Mauro S, Pappalardo A, Rabuazzo AM, Purrello M, Purrello F, Piro S. Altered expression of uncoupling protein 2 in GLP-1-producing cells after chronic high glucose exposure: implications for the pathogenesis of diabetes mellitus. Am J Physiol Cell Physiol 2016; 310:C558-67. [DOI: 10.1152/ajpcell.00148.2015] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Accepted: 01/06/2016] [Indexed: 01/11/2023]
Abstract
Glucagon-like peptide-1 (GLP-1) is a gut L-cell hormone that enhances glucose-stimulated insulin secretion. Several approaches that prevent GLP-1 degradation or activate the GLP-1 receptor are being used to treat type 2 diabetes mellitus (T2DM) patients. In T2DM, GLP-1 secretion has been suggested to be impaired, and this defect appears to be a consequence rather than a cause of impaired glucose homeostasis. However, although defective GLP-1 secretion has been correlated with insulin resistance, little is known about the direct effects of chronic high glucose concentrations, which are typical in diabetes patients, on GLP-1-secreting cell function. In the present study, we demonstrate that glucotoxicity directly affects GLP-1 secretion in GLUTag cells chronically exposed to high glucose. Our results indicate that this abnormality is associated with a decrease in ATP production due to the elevated expression of mitochondrial uncoupling protein 2 (UCP2). Furthermore, UCP2 inhibition using small interfering RNA (siRNA) and the application of glibenclamide, an ATP-sensitive potassium (KATP+) channel blocker, reverse the GLP-1 secretion defect induced by chronic high-glucose treatment. These results show that glucotoxicity diminishes the secretory responsiveness of GLP-1-secreting cells to acute glucose stimulation. We conclude that the loss of the incretin effect, as observed in T2DM patients, could at least partially depend on hyperglycemia, which is typical in diabetes patients. Such an understanding may not only provide new insight into diabetes complications but also ultimately contribute to the identification of novel molecular targets within intestinal L-cells for controlling and improving endogenous GLP-1 secretion.
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Affiliation(s)
- Francesca Urbano
- Department of Clinical and Experimental Medicine, Garibaldi-Nesima Hospital, University of Catania, Catania, Italy; and
| | - Agnese Filippello
- Department of Clinical and Experimental Medicine, Garibaldi-Nesima Hospital, University of Catania, Catania, Italy; and
| | - Antonino Di Pino
- Department of Clinical and Experimental Medicine, Garibaldi-Nesima Hospital, University of Catania, Catania, Italy; and
| | - Davide Barbagallo
- Department of BioMedical Sciences and BioTechnology, section of Biology and Genetics Giovanni Sichel, Unit of Molecular, Genome and Complex Systems BioMedicine, University of Catania, Catania, Italy
| | - Stefania Di Mauro
- Department of Clinical and Experimental Medicine, Garibaldi-Nesima Hospital, University of Catania, Catania, Italy; and
| | - Alessandro Pappalardo
- Department of Clinical and Experimental Medicine, Garibaldi-Nesima Hospital, University of Catania, Catania, Italy; and
| | - Agata Maria Rabuazzo
- Department of Clinical and Experimental Medicine, Garibaldi-Nesima Hospital, University of Catania, Catania, Italy; and
| | - Michele Purrello
- Department of BioMedical Sciences and BioTechnology, section of Biology and Genetics Giovanni Sichel, Unit of Molecular, Genome and Complex Systems BioMedicine, University of Catania, Catania, Italy
| | - Francesco Purrello
- Department of Clinical and Experimental Medicine, Garibaldi-Nesima Hospital, University of Catania, Catania, Italy; and
| | - Salvatore Piro
- Department of Clinical and Experimental Medicine, Garibaldi-Nesima Hospital, University of Catania, Catania, Italy; and
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27
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Gil-Lozano M, Wu WK, Martchenko A, Brubaker PL. High-Fat Diet and Palmitate Alter the Rhythmic Secretion of Glucagon-Like Peptide-1 by the Rodent L-cell. Endocrinology 2016; 157:586-99. [PMID: 26646204 DOI: 10.1210/en.2015-1732] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Secretion of the incretin hormone, glucagon-like peptide-1 (GLP-1), by the intestinal L-cell is rhythmically regulated by an independent molecular clock. However, the impact of factors known to affect the activity of similar cell-autonomous clocks, such as circulating glucocorticoids and high-fat feeding, on GLP-1 secretory patterns remains to be elucidated. Herein the role of the endogenous corticosterone rhythm on the pattern of GLP-1 and insulin nutrient-induced responses was examined in corticosterone pellet-implanted rats. Moreover, the impact of nutrient excess on the time-dependent secretion of both hormones was assessed in rats fed a high-fat, high-sucrose diet. Finally, the effects of the saturated fatty acid, palmitate, on the L-cell molecular clock and GLP-1 secretion were investigated in vitro using murine GLUTag L-cells. Diurnal variations in GLP-1 and insulin nutrient-induced responses were maintained in animals lacking an endogenous corticosterone rhythm, suggesting that glucocorticoids are not the predominant entrainment factor for L-cell rhythmic activity. In addition to hyperglycemia, hyperinsulinemia, insulin resistance, and disorganization of feeding behavior, high-fat high-sucrose-fed rats showed a total abrogation of the diurnal variation in GLP-1 and insulin nutrient-induced responses, with comparable levels of both hormones at the normal peak (5:00 pm) and trough (5:00 am) of their daily pattern. Finally, palmitate incubation induced profound derangements in the rhythmic expression of circadian oscillators in GLUTag L-cells and severely impaired the secretory activity of these cells. Collectively our findings demonstrate that obesogenic diets disrupt the rhythmic activity of the L-cell, partially through a direct effect of specific nutritional components.
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Affiliation(s)
- Manuel Gil-Lozano
- Departments of Physiology (M.G.-L., W.K.W., A.M., P.L.B.) and Medicine (P.L.B.), University of Toronto, Toronto, Ontario, Canada M5S 1A8
| | - W Kelly Wu
- Departments of Physiology (M.G.-L., W.K.W., A.M., P.L.B.) and Medicine (P.L.B.), University of Toronto, Toronto, Ontario, Canada M5S 1A8
| | - Alexandre Martchenko
- Departments of Physiology (M.G.-L., W.K.W., A.M., P.L.B.) and Medicine (P.L.B.), University of Toronto, Toronto, Ontario, Canada M5S 1A8
| | - Patricia L Brubaker
- Departments of Physiology (M.G.-L., W.K.W., A.M., P.L.B.) and Medicine (P.L.B.), University of Toronto, Toronto, Ontario, Canada M5S 1A8
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28
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Haufe TC, Gilley AD, Goodrich KM, Ryan CM, Smithson AT, Hulver MW, Liu D, Neilson AP. Grape powder attenuates the negative effects of GLP-1 receptor antagonism by exendin-3 (9–39) in a normoglycemic mouse model. Food Funct 2016; 7:2692-705. [DOI: 10.1039/c6fo00122j] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Acute oral administration of grape powder attenuates the hyperglycemic effects of GLP-1 receptor antagonism in rats.
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Affiliation(s)
- T. C. Haufe
- Department of Food Science and Technology
- Virginia Polytechnic Institute and State University
- Blacksburg
- USA
| | - A. D. Gilley
- Department of Food Science and Technology
- Virginia Polytechnic Institute and State University
- Blacksburg
- USA
| | - K. M. Goodrich
- Department of Food Science and Technology
- Virginia Polytechnic Institute and State University
- Blacksburg
- USA
| | - C. M. Ryan
- Department of Food Science and Technology
- Virginia Polytechnic Institute and State University
- Blacksburg
- USA
| | - A. T. Smithson
- Department of Food Science and Technology
- Virginia Polytechnic Institute and State University
- Blacksburg
- USA
| | - M. W. Hulver
- Department of Human Nutrition
- Foods and Exercise
- Virginia Polytechnic Institute and State University
- Blacksburg
- USA
| | - D. Liu
- Department of Human Nutrition
- Foods and Exercise
- Virginia Polytechnic Institute and State University
- Blacksburg
- USA
| | - A. P. Neilson
- Department of Food Science and Technology
- Virginia Polytechnic Institute and State University
- Blacksburg
- USA
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