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Grieve LM, Rani A, ZeRuth GT. Downregulation of Glis3 in INS1 cells exposed to chronically elevated glucose contributes to glucotoxicity-associated β cell dysfunction. Islets 2024; 16:2344622. [PMID: 38652652 PMCID: PMC11042057 DOI: 10.1080/19382014.2024.2344622] [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: 12/06/2023] [Accepted: 04/15/2024] [Indexed: 04/25/2024] Open
Abstract
Chronically elevated levels of glucose are deleterious to pancreatic β cells and contribute to β cell dysfunction, which is characterized by decreased insulin production and a loss of β cell identity. The Krüppel-like transcription factor, Glis3 has previously been shown to positively regulate insulin transcription and mutations within the Glis3 locus have been associated with the development of several pathologies including type 2 diabetes mellitus. In this report, we show that Glis3 is significantly downregulated at the transcriptional level in INS1 832/13 cells within hours of being subjected to high glucose concentrations and that diminished expression of Glis3 is at least partly attributable to increased oxidative stress. CRISPR/Cas9-mediated knockdown of Glis3 indicated that the transcription factor was required to maintain normal levels of both insulin and MafA expression and reduced Glis3 expression was concomitant with an upregulation of β cell disallowed genes. We provide evidence that Glis3 acts similarly to a pioneer factor at the insulin promoter where it permissively remodels the chromatin to allow access to a transcriptional regulatory complex including Pdx1 and MafA. Finally, evidence is presented that Glis3 can positively regulate MafA transcription through its pancreas-specific promoter and that MafA reciprocally regulates Glis3 expression. Collectively, these results suggest that decreased Glis3 expression in β cells exposed to chronic hyperglycemia may contribute significantly to reduced insulin transcription and a loss of β cell identity.
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Affiliation(s)
- LilyAnne M. Grieve
- Department of Biological Sciences, Murray State University, Murray, KY, USA
| | - Abhya Rani
- Department of Biological Sciences, Murray State University, Murray, KY, USA
| | - Gary T. ZeRuth
- Department of Biological Sciences, Murray State University, Murray, KY, USA
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2
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Nrf2 and Antioxidant Response in Animal Models of Type 2 Diabetes. Int J Mol Sci 2023; 24:ijms24043082. [PMID: 36834496 PMCID: PMC9961396 DOI: 10.3390/ijms24043082] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 01/18/2023] [Accepted: 01/30/2023] [Indexed: 02/09/2023] Open
Abstract
This perspective examines the proposition that chronically elevated blood glucose levels caused by type 2 diabetes (T2D) harm body tissues by locally generating reactive oxygen species (ROS). A feed-forward scenario is described in which the initial onset of defective beta cell function T2D becomes sustained and causes chronic elevations in blood glucose, which flood metabolic pathways throughout the body, giving rise to abnormally high local levels of ROS. Most cells can defend themselves via a full complement of antioxidant enzymes that are activated by ROS. However, the beta cell itself does not contain catalase or glutathione peroxidases and thereby runs a greater risk of ROS-induced damage. In this review, previously published experiments are revisited to examine the concept that chronic hyperglycemia can lead to oxidative stress in the beta cell, how this relates to the absence of beta cell glutathione peroxidase (GPx) activity, and whether this deficiency might be ameliorated by genetic enrichment of beta cell GPx and by oral antioxidants, including ebselen, a GPx mimetic.
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3
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Kohara Y, Ikai S, Yoshihara A, Murao K, Sugiyama Y. Effect of chronic exposure to ketohexoses on pancreatic β-cell function in INS-1 rat insulinoma cells. Biosci Biotechnol Biochem 2023; 87:163-170. [PMID: 36413460 DOI: 10.1093/bbb/zbac190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2022] [Accepted: 11/16/2022] [Indexed: 11/23/2022]
Abstract
Glucotoxicity, impaired insulin secretion, suppression of insulin gene expression, and apoptosis, in pancreatic β-cells caused by chronic hyperglycemia is a key component of the pathogenesis of type 2 diabetes. Recently, it has been reported that rare sugar d-allulose has antihyperglycemic and antihyperlipidemic effects in diabetic rats. However, the direct effects of rare sugars including d-allulose on pancreatic β-cell function are unclear. In this study, we investigated whether chronic exposure to ketohexoses causes glucotoxicity, suppression of insulin gene expression, and apoptosis, in INS-1 rat pancreatic insulinoma cells. d-Fructose, d-tagatose, l-allulose, and l-sorbose treatment for 1-week reduced insulin gene expression, whereas d-allulose, d-sorbose, l-fructose, and l-tagatose did not. All ketohexoses were transported into INS-1 cells, but were not metabolized. In addition, the ketohexoses did not induce apoptosis and did not affect glucose metabolism. These results suggest that long-term administration of d-allulose, d-sorbose, l-fructose, and l-tagatose does not affect pancreatic β-cell function.
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Affiliation(s)
- Yuri Kohara
- Department of Applied Biological Science, Faculty of Agriculture, Kagawa University, Miki, Kagawa, Japan
| | - Shuta Ikai
- Department of Applied Biological Science, Faculty of Agriculture, Kagawa University, Miki, Kagawa, Japan
| | - Akihide Yoshihara
- International Institute of Rare Sugar Research and Education, Kagawa University, Miki, Kagawa, Japan
| | - Koji Murao
- Department of Endocrinology and Metabolism, Faculty of Medicine, Kagawa University, Miki, Kagawa, Japan
| | - Yasunori Sugiyama
- Department of Applied Biological Science, Faculty of Agriculture, Kagawa University, Miki, Kagawa, Japan
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4
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Zhao G, Xu H, Li H, Zhang J, Gao J, Cai M, Wang H, Shi Y, Wang H. Regulatory Mechanisms of SNAP-25-Associated Insulin Release Revealed by Live-Cell Confocal and Single-Molecule Localization Imaging. Anal Chem 2022; 94:15307-15314. [DOI: 10.1021/acs.analchem.2c02677] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Guanfang Zhao
- State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin 130022, P. R. China
- University of Science and Technology of China, Hefei, Anhui 230026, P. R. China
| | - Haijiao Xu
- State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin 130022, P. R. China
| | - Hongru Li
- State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin 130022, P. R. China
- University of Science and Technology of China, Hefei, Anhui 230026, P. R. China
| | - Jinrui Zhang
- State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin 130022, P. R. China
| | - Jing Gao
- State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin 130022, P. R. China
| | - Mingjun Cai
- State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin 130022, P. R. China
| | - Huili Wang
- State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin 130022, P. R. China
| | - Yan Shi
- State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin 130022, P. R. China
| | - Hongda Wang
- State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, Jilin 130022, P. R. China
- University of Science and Technology of China, Hefei, Anhui 230026, P. R. China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, Shandong 266237, P. R. China
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5
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Perge K, Nicolino M. Variable phenotypes of individual and family monogenic cases with hyperinsulinism and diabetes: a systematic review. Rev Endocr Metab Disord 2022; 23:1063-1078. [PMID: 35996042 DOI: 10.1007/s11154-022-09749-2] [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] [Accepted: 08/01/2022] [Indexed: 10/15/2022]
Abstract
Maturity-Onset Diabetes of the Youth (MODY) diabetes remains commonly misdiagnosed. A monogenic form should be suspected in individuals presenting hyperinsulinemic hypoglycemia (HH) associated with, either later development of MODY (hypoglycemia-remission-diabetes sequence), or with first/second-degree family history of diabetes. Herein, we aimed to describe this individual or family monogenic association between HH and diabetes, and identify potential genotype-phenotype correlations. We conducted a systematic review of 26 studies, including a total of 67 patients with this association resulting from variants in GCK (n = 5 cases), ABCC8 (n = 29), HNF1A (n = 5), or HNF4A (n = 28). A family history of hypoglycemia and/or diabetes was present in 91% of cases (61/67). Median age at first hypoglycemia was 24 h after birth. Diazoxide was initiated in 46 children (46/67-69%); responsiveness was found in 91% (42/46). Median HH duration was three years (1 day-25 years). Twenty-three patients (23/67-34%) later developed diabetes (median age: 13 years; range: 8-48); more frequently in those untreated with diazoxide. This association was most commonly inherited in an autosomal dominant manner (43/48-90%). Some genes were associated with less severe initial hypoglycemia (HNF1A), shorter duration of HH (HNF4A), and more maternal (ABCC8) or paternal (HNF4A) transmission. This study illustrates that the same genotype can give a biphasic phenotype in the same person or a reverse phenotype in the same family. Wider awareness of this association is necessary in pediatrics to establish annual monitoring of patients who have presented HH, and during maternity to screen diabetes and optimize genetic counseling and management of pregnancy, childbirth, and the newborn.PROSPERO registration: CRD42020178265.
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Affiliation(s)
- Kevin Perge
- Service d'Endocrinologie Pédiatrique Et Pédiatrie Générale, Hospices Civils de Lyon, Hôpital Femme Mère Enfant, 59 Boulevard Pinel, 69677, Bron, France
- Université Claude Bernard, Lyon 1, 8 Avenue Rockefeller, 69008, Lyon, France
| | - Marc Nicolino
- Service d'Endocrinologie Pédiatrique Et Pédiatrie Générale, Hospices Civils de Lyon, Hôpital Femme Mère Enfant, 59 Boulevard Pinel, 69677, Bron, France.
- Université Claude Bernard, Lyon 1, 8 Avenue Rockefeller, 69008, Lyon, France.
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6
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Huang K, Luo X, Zhong Y, Deng L, Feng J. New insights into the role of melatonin in diabetic cardiomyopathy. Pharmacol Res Perspect 2022; 10:e00904. [PMID: 35005848 PMCID: PMC8929360 DOI: 10.1002/prp2.904] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Accepted: 11/25/2021] [Indexed: 12/13/2022] Open
Abstract
Diabetic cardiovascular complications and impaired cardiac function are considered to be the main causes of death in diabetic patients worldwide, especially patients with type 2 diabetes mellitus (T2DM). An increasing number of studies have shown that melatonin, as the main product secreted by the pineal gland, plays a vital role in the occurrence and development of diabetes. Melatonin improves myocardial cell metabolism, reduces vascular endothelial cell death, reverses microcirculation disorders, reduces myocardial fibrosis, reduces oxidative and endoplasmic reticulum stress, regulates cell autophagy and apoptosis, and improves mitochondrial function, all of which are the characteristics of diabetic cardiomyopathy (DCM). This review focuses on the role of melatonin in DCM. We also discuss new molecular findings that might facilitate a better understanding of the underlying mechanism. Finally, we propose potential new therapeutic strategies for patients with T2DM.
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Affiliation(s)
- Keming Huang
- Department of Cardiology, The Affiliated Hospital of Southwest Medical University, Luzhou, China.,Key Laboratory of Medical Electrophysiology, Ministry of Education & Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, China
| | - Xianling Luo
- Department of Cardiology, The Affiliated Hospital of Southwest Medical University, Luzhou, China.,Key Laboratory of Medical Electrophysiology, Ministry of Education & Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, China
| | - Yi Zhong
- Department of Cardiology, The Affiliated Hospital of Southwest Medical University, Luzhou, China.,Key Laboratory of Medical Electrophysiology, Ministry of Education & Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, China
| | - Li Deng
- Department of Cardiology, The Affiliated Hospital of Southwest Medical University, Luzhou, China.,Key Laboratory of Medical Electrophysiology, Ministry of Education & Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, China
| | - Jian Feng
- Department of Cardiology, The Affiliated Hospital of Southwest Medical University, Luzhou, China.,Key Laboratory of Medical Electrophysiology, Ministry of Education & Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, China
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7
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Baumel-Alterzon S, Scott DK. Regulation of Pdx1 by oxidative stress and Nrf2 in pancreatic beta-cells. Front Endocrinol (Lausanne) 2022; 13:1011187. [PMID: 36187092 PMCID: PMC9521308 DOI: 10.3389/fendo.2022.1011187] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Accepted: 08/26/2022] [Indexed: 01/05/2023] Open
Abstract
The beta-cell identity gene, pancreatic duodenal homeobox 1 (Pdx1), plays critical roles in many aspects of the life of beta-cells including differentiation, maturation, function, survival and proliferation. High levels of reactive oxygen species (ROS) are extremely toxic to cells and especially to beta-cells due to their relatively low expression of antioxidant enzymes. One of the major mechanisms for beta-cell dysfunction in type-2 diabetes results from oxidative stress-dependent inhibition of PDX1 levels and function. ROS inhibits Pdx1 by reducing Pdx1 mRNA and protein levels, inhibiting PDX1 nuclear localization, and suppressing PDX1 coactivator complexes. The nuclear factor erythroid 2-related factor (Nrf2) antioxidant pathway controls the redox balance and allows the maintenance of high Pdx1 levels. Therefore, pharmacological activation of the Nrf2 pathway may alleviate diabetes by preserving Pdx1 levels.
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Affiliation(s)
- Sharon Baumel-Alterzon
- Diabetes, Obesity and Metabolism Institute, Icahn School of Medicine at Mount Sinai, New York, NY, United States
- Mindich Child Health and Development Institute, Icahn School of Medicine at Mount Sinai, New York, NY, United States
- *Correspondence: Sharon Baumel-Alterzon,
| | - Donald K. Scott
- Diabetes, Obesity and Metabolism Institute, Icahn School of Medicine at Mount Sinai, New York, NY, United States
- Mindich Child Health and Development Institute, Icahn School of Medicine at Mount Sinai, New York, NY, United States
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8
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Dinić S, Arambašić Jovanović J, Uskoković A, Mihailović M, Grdović N, Tolić A, Rajić J, Đorđević M, Vidaković M. Oxidative stress-mediated beta cell death and dysfunction as a target for diabetes management. Front Endocrinol (Lausanne) 2022; 13:1006376. [PMID: 36246880 PMCID: PMC9554708 DOI: 10.3389/fendo.2022.1006376] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 09/05/2022] [Indexed: 11/14/2022] Open
Abstract
The biggest drawback of a current diabetes therapy is the treatment of the consequences not the cause of the disease. Regardless of the diabetes type, preservation and recovery of functional pancreatic beta cells stands as the biggest challenge in the treatment of diabetes. Free radicals and oxidative stress are among the major mediators of autoimmune destruction of beta cells in type 1 diabetes (T1D) or beta cell malfunction and death provoked by glucotoxicity and insulin resistance in type 2 diabetes (T2D). Additionally, oxidative stress reduces functionality of beta cells in T2D by stimulating their de-/trans-differentiation through the loss of transcription factors critical for beta cell development, maturity and regeneration. This review summarizes up to date clarified redox-related mechanisms involved in regulating beta cell identity and death, underlining similarities and differences between T1D and T2D. The protective effects of natural antioxidants on the oxidative stress-induced beta cell failure were also discussed. Considering that oxidative stress affects epigenetic regulatory mechanisms involved in the regulation of pancreatic beta cell survival and insulin secretion, this review highlighted huge potential of epigenetic therapy. Special attention was paid on application of the state-of-the-art CRISPR/Cas9 technology, based on targeted epigenome editing with the purpose of changing the differentiation state of different cell types, making them insulin-producing with ability to attenuate diabetes. Clarification of the above-mentioned mechanisms could provide better insight into diabetes etiology and pathogenesis, which would allow development of novel, potentially more efficient therapeutic strategies for the prevention or reversion of beta cell loss.
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9
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Mukherjee N, Lin L, Contreras CJ, Templin AT. β-Cell Death in Diabetes: Past Discoveries, Present Understanding, and Potential Future Advances. Metabolites 2021; 11:796. [PMID: 34822454 PMCID: PMC8620854 DOI: 10.3390/metabo11110796] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 11/15/2021] [Accepted: 11/18/2021] [Indexed: 12/19/2022] Open
Abstract
β-cell death is regarded as a major event driving loss of insulin secretion and hyperglycemia in both type 1 and type 2 diabetes mellitus. In this review, we explore past, present, and potential future advances in our understanding of the mechanisms that promote β-cell death in diabetes, with a focus on the primary literature. We first review discoveries of insulin insufficiency, β-cell loss, and β-cell death in human diabetes. We discuss findings in humans and mouse models of diabetes related to autoimmune-associated β-cell loss and the roles of autoreactive T cells, B cells, and the β cell itself in this process. We review discoveries of the molecular mechanisms that underlie β-cell death-inducing stimuli, including proinflammatory cytokines, islet amyloid formation, ER stress, oxidative stress, glucotoxicity, and lipotoxicity. Finally, we explore recent perspectives on β-cell death in diabetes, including: (1) the role of the β cell in its own demise, (2) methods and terminology for identifying diverse mechanisms of β-cell death, and (3) whether non-canonical forms of β-cell death, such as regulated necrosis, contribute to islet inflammation and β-cell loss in diabetes. We believe new perspectives on the mechanisms of β-cell death in diabetes will provide a better understanding of this pathological process and may lead to new therapeutic strategies to protect β cells in the setting of diabetes.
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Affiliation(s)
- Noyonika Mukherjee
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202, USA;
- Lilly Diabetes Center of Excellence, Indiana Biosciences Research Institute, Indianapolis, IN 46202, USA; (L.L.); (C.J.C.)
| | - Li Lin
- Lilly Diabetes Center of Excellence, Indiana Biosciences Research Institute, Indianapolis, IN 46202, USA; (L.L.); (C.J.C.)
| | - Christopher J. Contreras
- Lilly Diabetes Center of Excellence, Indiana Biosciences Research Institute, Indianapolis, IN 46202, USA; (L.L.); (C.J.C.)
- Department of Medicine, Roudebush Veterans Affairs Medical Center, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Andrew T. Templin
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202, USA;
- Lilly Diabetes Center of Excellence, Indiana Biosciences Research Institute, Indianapolis, IN 46202, USA; (L.L.); (C.J.C.)
- Department of Medicine, Roudebush Veterans Affairs Medical Center, Indiana University School of Medicine, Indianapolis, IN 46202, USA
- Center for Diabetes and Metabolic Diseases, School of Medicine, Indiana University, Indianapolis, IN 46202, USA
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10
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FoxA2 and RNA Pol II mediate human islet amyloid polypeptide turnover in ER-stressed pancreatic β-cells. Biochem J 2021; 478:1261-1282. [PMID: 33650632 DOI: 10.1042/bcj20200984] [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: 12/14/2020] [Revised: 02/26/2021] [Accepted: 03/02/2021] [Indexed: 12/25/2022]
Abstract
Here, we investigated transcriptional and trafficking mechanisms of human islet amyloid polypeptide (hIAPP) in normal and stressed β-cells. In high glucose-challenged human islets and rat insulinoma cells overexpressing hIAPP, cell fractionation studies revealed increased accumulation of hIAPP. Unexpectedly, a significant fraction (up to 22%) of hIAPP was found in the nuclear soluble and chromatin-enriched fractions of cultured human islet and rat insulinoma cells. The nucleolar accumulation of monomeric forms of hIAPP did not have any adverse effect on the proliferation of β-cells nor did it affect nucleolar organization or function. However, intact nucleolar organization and function were essential for hIAPP expression under normal and ER-stress conditions as RNA polymerase II inhibitor, α-amanitin, reduced hIAPP protein expression evoked by high glucose and thapsigargin. Promoter activity studies revealed the essential role of transcription factor FoxA2 in hIAPP promoter activation in ER-stressed β-cells. Transcriptome and secretory studies demonstrate that the biosynthetic and secretory capacity of islet β-cells was preserved during ER stress. Thus, the main reason for increased intracellular hIAPP accumulation is its enhanced biosynthesis under these adverse conditions.
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11
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Herlea-Pana O, Eeda V, Undi RB, Lim HY, Wang W. Pharmacological Inhibition of Inositol-Requiring Enzyme 1α RNase Activity Protects Pancreatic Beta Cell and Improves Diabetic Condition in Insulin Mutation-Induced Diabetes. Front Endocrinol (Lausanne) 2021; 12:749879. [PMID: 34675883 PMCID: PMC8524045 DOI: 10.3389/fendo.2021.749879] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 09/20/2021] [Indexed: 12/25/2022] Open
Abstract
β-cell ER stress plays an important role in β-cell dysfunction and death during the pathogenesis of diabetes. Proinsulin misfolding is regarded as one of the primary initiating factors of ER stress and unfolded protein response (UPR) activation in β-cells. Here, we found that the ER stress sensor inositol-requiring enzyme 1α (IRE1α) was activated in the Akita mice, a mouse model of mutant insulin gene-induced diabetes of youth (MIDY), a monogenic diabetes. Normalization of IRE1α RNase hyperactivity by pharmacological inhibitors significantly ameliorated the hyperglycemic conditions and increased serum insulin levels in Akita mice. These benefits were accompanied by a concomitant protection of functional β-cell mass, as shown by the suppression of β-cell apoptosis, increase in mature insulin production and reduction of proinsulin level. At the molecular level, we observed that the expression of genes associated with β-cell identity and function was significantly up-regulated and ER stress and its associated inflammation and oxidative stress were suppressed in islets from Akita mice treated with IRE1α RNase inhibitors. This study provides the evidence of the in vivo efficacy of IRE1α RNase inhibitors in Akita mice, pointing to the possibility of targeting IRE1α RNase as a therapeutic direction for the treatment of diabetes.
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Affiliation(s)
- Oana Herlea-Pana
- Department of Medicine, Division of Endocrinology, Harold Hamm Diabetes Center, Oklahoma City, OK, United States
| | - Venkateswararao Eeda
- Department of Medicine, Division of Endocrinology, Harold Hamm Diabetes Center, Oklahoma City, OK, United States
| | - Ram Babu Undi
- Department of Physiology, Harold Hamm Diabetes Center, The University of Oklahoma Health Science Center, Oklahoma City, OK, United States
| | - Hui-Ying Lim
- Department of Physiology, Harold Hamm Diabetes Center, The University of Oklahoma Health Science Center, Oklahoma City, OK, United States
| | - Weidong Wang
- Department of Medicine, Division of Endocrinology, Harold Hamm Diabetes Center, Oklahoma City, OK, United States
- *Correspondence: Weidong Wang, , orcid.org/0000-0003-3619-0953
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12
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Berger C, Zdzieblo D. Glucose transporters in pancreatic islets. Pflugers Arch 2020; 472:1249-1272. [PMID: 32394191 PMCID: PMC7462922 DOI: 10.1007/s00424-020-02383-4] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Revised: 04/20/2020] [Accepted: 04/22/2020] [Indexed: 02/07/2023]
Abstract
The fine-tuning of glucose uptake mechanisms is rendered by various glucose transporters with distinct transport characteristics. In the pancreatic islet, facilitative diffusion glucose transporters (GLUTs), and sodium-glucose cotransporters (SGLTs) contribute to glucose uptake and represent important components in the glucose-stimulated hormone release from endocrine cells, therefore playing a crucial role in blood glucose homeostasis. This review summarizes the current knowledge about cell type-specific expression profiles as well as proven and putative functions of distinct GLUT and SGLT family members in the human and rodent pancreatic islet and further discusses their possible involvement in onset and progression of diabetes mellitus. In context of GLUTs, we focus on GLUT2, characterizing the main glucose transporter in insulin-secreting β-cells in rodents. In addition, we discuss recent data proposing that other GLUT family members, namely GLUT1 and GLUT3, render this task in humans. Finally, we summarize latest information about SGLT1 and SGLT2 as representatives of the SGLT family that have been reported to be expressed predominantly in the α-cell population with a suggested functional role in the regulation of glucagon release.
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Affiliation(s)
- Constantin Berger
- Tissue Engineering & Regenerative Medicine, University Hospital Würzburg, Röntgenring 11, 97070, Würzburg, Germany
| | - Daniela Zdzieblo
- Tissue Engineering & Regenerative Medicine, University Hospital Würzburg, Röntgenring 11, 97070, Würzburg, Germany.
- Fraunhofer Institute for Silicate Research (ISC), Translational Center Regenerative Therapies, Neunerplatz 2, 97082, Würzburg, Germany.
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13
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Petrovic I, Pejnovic N, Ljujic B, Pavlovic S, Miletic Kovacevic M, Jeftic I, Djukic A, Draginic N, Andjic M, Arsenijevic N, Lukic ML, Jovicic N. Overexpression of Galectin 3 in Pancreatic β Cells Amplifies β-Cell Apoptosis and Islet Inflammation in Type-2 Diabetes in Mice. Front Endocrinol (Lausanne) 2020; 11:30. [PMID: 32117058 PMCID: PMC7018709 DOI: 10.3389/fendo.2020.00030] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Accepted: 01/15/2020] [Indexed: 12/23/2022] Open
Abstract
Aims/Hypothesis: Galectin 3 appears to play a proinflammatory role in several inflammatory and autoimmune diseases. Also, there is evidence that galectin 3 plays a role in both type-1 and type-2 diabetes. During obesity, hematopoietic cell-derived galectin 3 induces insulin resistance. While the role of galectin 3 expressed in islet-invading immune cells in both type-1 and type-2 diabetes has been studied, the importance of the expression of this molecule on the target pancreatic β cells has not been defined. Methods: To clarify the role of galectin 3 expression in β cells during obesity-induced diabetogenesis, we developed transgenic mice selectively overexpressing galectin 3 in β cells and tested their susceptibility to obesity-induced type-2 diabetes. Obesity was induced with a 16-week high-fat diet regime. Pancreatic β cells were tested for susceptibility to apoptosis induced by non-esterified fatty acids and cytokines as well as parameters of oxidative stress. Results: Our results demonstrated that overexpression of galectin 3 increases β-cell apoptosis in HFD conditions and increases the percentage of proinflammatory F4/80+ macrophages in islets that express galectin 3 and TLR4. In isolated islets, we have shown that galectin 3 overexpression increases cytokine and palmitate-triggered β-cell apoptosis and also increases NO2--induced oxidative stress of β cells. Also, in pancreatic lymph nodes, macrophages were shifted toward a proinflammatory TNF-α-producing phenotype. Conclusions/Interpretation: By complementary in vivo and in vitro approaches, we have shown that galectin 3-overexpression facilitates β-cell damage, enhances cytokine and palmitate-triggered β-cell apoptosis, and increases NO2--induced oxidative stress in β cells. Further, the results suggest that increased expression of galectin 3 in the pancreatic β cells affects the metabolism of glucose and glycoregulation in mice on a high-fat diet, affecting both fasting glycemic values and glycemia after glucose loading.
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Affiliation(s)
- Ivica Petrovic
- Center for Molecular Medicine and Stem Cell Research, Faculty of Medical Sciences, University of Kragujevac, Kragujevac, Serbia
- Department of Pathophysiology, Faculty of Medical Sciences, University of Kragujevac, Kragujevac, Serbia
| | - Nada Pejnovic
- Center for Molecular Medicine and Stem Cell Research, Faculty of Medical Sciences, University of Kragujevac, Kragujevac, Serbia
- Department of Pathophysiology, Faculty of Medical Sciences, University of Kragujevac, Kragujevac, Serbia
| | - Biljana Ljujic
- Department of Genetics, Faculty of Medical Sciences, University of Kragujevac, Kragujevac, Serbia
| | - Sladjana Pavlovic
- Center for Molecular Medicine and Stem Cell Research, Faculty of Medical Sciences, University of Kragujevac, Kragujevac, Serbia
| | - Marina Miletic Kovacevic
- Department of Histology and Embryology, Faculty of Medical Sciences, University of Kragujevac, Kragujevac, Serbia
| | - Ilija Jeftic
- Center for Molecular Medicine and Stem Cell Research, Faculty of Medical Sciences, University of Kragujevac, Kragujevac, Serbia
- Department of Pathophysiology, Faculty of Medical Sciences, University of Kragujevac, Kragujevac, Serbia
| | - Aleksandar Djukic
- Department of Pathophysiology, Faculty of Medical Sciences, University of Kragujevac, Kragujevac, Serbia
| | - Nevena Draginic
- Department of Pharmacy, Faculty of Medical Sciences, University of Kragujevac, Kragujevac, Serbia
| | - Marijana Andjic
- Department of Pharmacy, Faculty of Medical Sciences, University of Kragujevac, Kragujevac, Serbia
| | - Nebojsa Arsenijevic
- Center for Molecular Medicine and Stem Cell Research, Faculty of Medical Sciences, University of Kragujevac, Kragujevac, Serbia
| | - Miodrag L. Lukic
- Center for Molecular Medicine and Stem Cell Research, Faculty of Medical Sciences, University of Kragujevac, Kragujevac, Serbia
- *Correspondence: Miodrag L. Lukic
| | - Nemanja Jovicic
- Department of Histology and Embryology, Faculty of Medical Sciences, University of Kragujevac, Kragujevac, Serbia
- Nemanja Jovicic
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14
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Ma J, He X, Cao Y, O’Dwyer K, Szigety KM, Wu Y, Gurung B, Feng Z, Katona BW, Hua X. Islet-specific Prmt5 excision leads to reduced insulin expression and glucose intolerance in mice. J Endocrinol 2020; 244:41-52. [PMID: 31539871 PMCID: PMC6864278 DOI: 10.1530/joe-19-0268] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Accepted: 09/19/2019] [Indexed: 12/14/2022]
Abstract
Protein arginine methyltransferase 5 (PRMT5), a symmetric arginine methyltransferase, regulates cell functions by influencing gene transcription through posttranslational modification of histones and non-histone proteins. PRMT5 interacts with multiple partners including menin, which controls beta cell homeostasis. However, the role of Prmt5 in pancreatic islets, particularly in beta cells, remains unclear. A mouse model with an islet-specific knockout (KO) of the Prmt5 gene was generated, and the influence of the Prmt5 excision on beta cells was investigated via morphologic and functional studies. Beta cell function was evaluated by glucose tolerance test (GTT) and glucose-stimulated insulin secretion (GSIS) test. Beta cell proliferation was evaluated by immunostaining. Gene expression change was determined by real-time qPCR. Molecular mechanisms were investigated in beta cells in vitro and in vivo in Prmt5 KO mice. The results show that islet-specific KO of Prmt5 reduced expression of the insulin gene and impaired glucose tolerance and GSIS in vivo. The mechanistic study indicated that PRMT5 is involved in the regulation of insulin gene transcription, likely via histone methylation-related chromatin remodeling. The reduced expression of insulin in beta cells in the Prmt5 KO mice may contribute to impaired glucose tolerance (IGT) and deficient GSIS in the mouse model. These results will provide new insights into exploring novel strategies to treat diabetes caused by insulin insufficiency.
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Affiliation(s)
- Jian Ma
- Department of Cancer Biology, Abramson Family Cancer Research Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19104
- Institute for Diabetes, Obesity, and Metabolism, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19104
| | - Xin He
- Department of Cancer Biology, Abramson Family Cancer Research Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19104
| | - Yan Cao
- Department of Cancer Biology, Abramson Family Cancer Research Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19104
- Institute for Diabetes, Obesity, and Metabolism, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19104
| | - Kienan O’Dwyer
- Department of Cancer Biology, Abramson Family Cancer Research Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19104
| | - Katherine M. Szigety
- Department of Cancer Biology, Abramson Family Cancer Research Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19104
| | - Yuan Wu
- Department of Cancer Biology, Abramson Family Cancer Research Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19104
| | - Buddha Gurung
- Department of Cancer Biology, Abramson Family Cancer Research Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19104
| | - Zijie Feng
- Department of Cancer Biology, Abramson Family Cancer Research Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19104
| | - Bryson W. Katona
- Department of Cancer Biology, Abramson Family Cancer Research Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19104
- Division of Gastroenterology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19104
| | - Xianxin Hua
- Department of Cancer Biology, Abramson Family Cancer Research Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19104
- Institute for Diabetes, Obesity, and Metabolism, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19104
- Corresponding author: Dr. Xianxin Hua, Department of Cancer Biology, Abramson Family Cancer Research Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA. 412 BRB II/III 421 Curie Boulevard, Philadelphia, PA 19104-6160, Phone: (215) 746-5565; Fax: (215) 746-5525;
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15
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Lysosomal degradation of newly formed insulin granules contributes to β cell failure in diabetes. Nat Commun 2019; 10:3312. [PMID: 31346174 PMCID: PMC6658524 DOI: 10.1038/s41467-019-11170-4] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2017] [Accepted: 06/27/2019] [Indexed: 02/06/2023] Open
Abstract
Compromised function of insulin-secreting pancreatic β cells is central to the development and progression of Type 2 Diabetes (T2D). However, the mechanisms underlying β cell failure remain incompletely understood. Here, we report that metabolic stress markedly enhances macroautophagy-independent lysosomal degradation of nascent insulin granules. In different model systems of diabetes including of human origin, stress-induced nascent granule degradation (SINGD) contributes to loss of insulin along with mammalian/mechanistic Target of Rapamycin (mTOR)-dependent suppression of macroautophagy. Expression of Protein Kinase D (PKD), a negative regulator of SINGD, is reduced in diabetic β cells. Pharmacological activation of PKD counters SINGD and delays the onset of T2D. Conversely, inhibition of PKD exacerbates SINGD, mitigates insulin secretion and accelerates diabetes. Finally, reduced levels of lysosomal tetraspanin CD63 prevent SINGD, leading to increased insulin secretion. Overall, our findings implicate aberrant SINGD in the pathogenesis of diabetes and suggest new therapeutic strategies to prevent β cell failure. Impaired beta-cell insulin secretion is a key pathological feature of type 2 diabetes. Here, the authors describe metabolic stress induced lysosomal degradation of newly formed insulin granules, independent of macroautophagy, as a potential mechanism for beta-cell dysfunction.
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16
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Hoard TM, Yang XP, Jetten AM, ZeRuth GT. PIAS-family proteins negatively regulate Glis3 transactivation function through SUMO modification in pancreatic β cells. Heliyon 2018; 4:e00709. [PMID: 30094379 PMCID: PMC6077130 DOI: 10.1016/j.heliyon.2018.e00709] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Revised: 02/09/2018] [Accepted: 07/23/2018] [Indexed: 11/28/2022] Open
Abstract
Gli-similar 3 (Glis3) is Krüppel-like transcription factor associated with the transcriptional regulation of insulin. Mutations within the Glis3 locus have been implicated in a number of pathologies including diabetes mellitus and hypothyroidism. Despite its clinical significance, little is known about the proteins and posttranslational modifications that regulate Glis3 transcriptional activity. In this report, we demonstrate that the SUMO-pathway associated proteins, PIASy and Ubc9 are capable of regulating Glis3 transactivation function through a SUMO-dependent mechanism. We present evidence that SUMOylation of Glis3 by PIAS-family proteins occurs at two conserved lysine residues within the Glis3 N-terminus and modification of Glis3 by SUMO dramatically inhibited insulin transcription. Finally, we provide evidence that Glis3 SUMOylation increases under conditions of chronically elevated glucose and correlates with decreased insulin transcription. Collectively, these results indicate that SUMOylation may serve as a mechanism to regulate Glis3 activity in β cells.
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Affiliation(s)
- Tyler M Hoard
- Department of Biological Sciences, Murray State University, Murray, KY, USA
| | - Xiao Ping Yang
- Cell Biology Group, Immunity, Inflammation, and Disease Laboratory, Division of Intramural Research, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC, USA
| | - Anton M Jetten
- Cell Biology Group, Immunity, Inflammation, and Disease Laboratory, Division of Intramural Research, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC, USA
| | - Gary T ZeRuth
- Department of Biological Sciences, Murray State University, Murray, KY, USA.,Cell Biology Group, Immunity, Inflammation, and Disease Laboratory, Division of Intramural Research, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC, USA
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17
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Shin H, Han JH, Yoon J, Sim HJ, Park TJ, Yang S, Lee EK, Kulkarni RN, Egan JM, Kim W. Blockade of cannabinoid 1 receptor improves glucose responsiveness in pancreatic beta cells. J Cell Mol Med 2018; 22:2337-2345. [PMID: 29431265 PMCID: PMC5867156 DOI: 10.1111/jcmm.13523] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Accepted: 12/01/2017] [Indexed: 01/19/2023] Open
Abstract
Cannabinoid 1 receptors (CB1Rs) are expressed in peripheral tissues, including islets of Langerhans, where their function(s) is under scrutiny. Using mouse β-cell lines, human islets and CB1R-null (CB1R-/- ) mice, we have now investigated the role of CB1Rs in modulating β-cell function and glucose responsiveness. Synthetic CB1R agonists diminished GLP-1-mediated cAMP accumulation and insulin secretion as well as glucose-stimulated insulin secretion in mouse β-cell lines and human islets. In addition, silencing CB1R in mouse β cells resulted in an increased expression of pro-insulin, glucokinase (GCK) and glucose transporter 2 (GLUT2), but this increase was lost in β cells lacking insulin receptor. Furthermore, CB1R-/- mice had increased pro-insulin, GCK and GLUT2 expression in β cells. Our results suggest that CB1R signalling in pancreatic islets may be harnessed to improve β-cell glucose responsiveness and preserve their function. Thus, our findings further support that blocking peripheral CB1Rs would be beneficial to β-cell function in type 2 diabetes.
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Affiliation(s)
- Hanho Shin
- Department of Molecular Science and TechnologyAjou UniversitySuwonSouth Korea
| | - Ji Hye Han
- Department of Molecular Science and TechnologyAjou UniversitySuwonSouth Korea
| | - Juhwan Yoon
- Department of Molecular Science and TechnologyAjou UniversitySuwonSouth Korea
| | - Hyo Jung Sim
- School of Life ScienceUlsan National Institute of Science and Technology (UNIST)UlsanSouth Korea
- Center for Genomic IntegrityInstitute for Basic ScienceUlsanSouth Korea
| | - Tae Joo Park
- School of Life ScienceUlsan National Institute of Science and Technology (UNIST)UlsanSouth Korea
- Center for Genomic IntegrityInstitute for Basic ScienceUlsanSouth Korea
| | - Siyoung Yang
- Department of PharmacologyAjou University School of MedicineSuwonSouth Korea
- Department of Biomedical SciencesAjou University Graduate School of MedicineSuwonSouth Korea
| | - Eun Kyung Lee
- Department of BiochemistryCollege of MedicineThe Catholic University of KoreaSeoulSouth Korea
| | - Rohit N. Kulkarni
- Department of Islet Cell and Regenerative BiologyJoslin Diabetes Center and Department of MedicineHarvard Medical SchoolHarvard Stem Cell InstituteBostonMAUSA
| | - Josephine M. Egan
- Laboratory of Clinical InvestigationNational Institute on AgingNational Institutes of HealthBaltimoreMDUSA
| | - Wook Kim
- Department of Molecular Science and TechnologyAjou UniversitySuwonSouth Korea
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18
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Gu W, Rebsdorf A, Hermansen K, Gregersen S, Jeppesen PB. The Dynamic Effects of Isosteviol on Insulin Secretion and Its Inability to Counteract the Impaired β-Cell Function during Gluco-, Lipo-, and Aminoacidotoxicity: Studies In Vitro. Nutrients 2018; 10:nu10020127. [PMID: 29373526 PMCID: PMC5852703 DOI: 10.3390/nu10020127] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Revised: 01/10/2018] [Accepted: 01/24/2018] [Indexed: 12/21/2022] Open
Abstract
Isosteviol (ISV), a diterpene molecule, is an isomer of the backbone structure of a group of substances with proven antidiabetic capabilities. The aim of this study was to investigate if ISV elicits dynamic insulin release from pancreatic islets and concomitantly is able to ameliorate gluco-, lipo-, and aminoacidotoxicity in clonal β-cell line (INS-1E) in relation to cell viability and insulin secretion. Isolated mice islets placed into perifusion chambers were perifused with 3.3 mM and 16.7 mM glucose with/without 10−7 M ISV. INS-1E cells were incubated for 72 h with either 30 mM glucose, 1 mM palmitate or 10 mM leucine with or without 10−7 M ISV. Cell viability was evaluated with a Cytotoxic Fluoro-test and insulin secretion was measured in Krebs-Ringer Buffer at 3.3 mM and 16.7 mM glucose. In the presence of 3.3 mM glucose, 10−7 M ISV did not change basal insulin secretion from perifused islets. However, at a high glucose level of 16.7 mM, 10−7 M ISV elicited a 2.5-fold increase (−ISV: 109.92 ± 18.64 ng/mL vs. +ISV: 280.15 ± 34.97 ng/mL; p < 0.01). After 72 h gluco-, lipo-, or aminoacidotoxicity in INS-1E cells, ISV treatment did not significantly affect cell viability (glucotoxicity, −ISV: 19.23 ± 0.83%, +ISV: 18.41 ± 0.90%; lipotoxicity, −ISV: 70.46 ± 3.15%, +ISV: 65.38 ± 2.81%; aminoacidotoxicity: −ISV: 8.12 ± 0.63%; +ISV: 7.75 ± 0.38%, all nonsignificant). ISV did not improve impaired insulin secretion (glucotoxicity, −ISV: 52.22 ± 2.90 ng/mL, +ISV: 47.24 ± 3.61 ng/mL; lipotoxicity, −ISV: 19.94 ± 4.10 ng/mL, +ISV: 22.12 ± 3.94 ng/mL; aminoacidotoxicity: −ISV: 32.13 ± 1.00 ng/mL; +ISV: 30.61 ± 1.54 ng/mL, all nonsignificant). In conclusion, ISV acutely stimulates insulin secretion at high but not at low glucose concentrations. However, ISV did not counteract cell viability or cell dysfunction during gluco-, lipo-, or aminoacidotoxicity in INS-1E cells.
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Affiliation(s)
- Wenqian Gu
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Tage-Hansens Gade 2, 8000 Aarhus C, Denmark.
| | - Andreas Rebsdorf
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Tage-Hansens Gade 2, 8000 Aarhus C, Denmark.
| | - Kjeld Hermansen
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Tage-Hansens Gade 2, 8000 Aarhus C, Denmark.
| | - Søren Gregersen
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Tage-Hansens Gade 2, 8000 Aarhus C, Denmark.
| | - Per Bendix Jeppesen
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Tage-Hansens Gade 2, 8000 Aarhus C, Denmark.
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19
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Abebe T, Mahadevan J, Bogachus L, Hahn S, Black M, Oseid E, Urano F, Cirulli V, Robertson RP. Nrf2/antioxidant pathway mediates β cell self-repair after damage by high-fat diet-induced oxidative stress. JCI Insight 2017; 2:92854. [PMID: 29263299 DOI: 10.1172/jci.insight.92854] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Accepted: 11/15/2017] [Indexed: 12/18/2022] Open
Abstract
Many theories have been advanced to better understand why β cell function and structure relentlessly deteriorate during the course of type 2 diabetes (T2D). These theories include inflammation, apoptosis, replication, neogenesis, autophagy, differentiation, dedifferentiation, and decreased levels of insulin gene regulatory proteins. However, none of these have considered the possibility that endogenous self-repair of existing β cells may be an important factor. To examine this hypothesis, we conducted studies with female Zucker diabetic fatty rats fed a high-fat diet (HFD) for 1, 2, 4, 7, 9, 18, or 28 days, followed by a return to regular chow for 2-3 weeks. Repair was defined as reversal of elevated blood glucose and of inappropriately low blood insulin levels caused by a HFD, as well as reversal of structural damage visualized by imaging studies. We observed evidence of functional β cell damage after a 9-day exposure to a HFD and then repair after 2-3 weeks of being returned to normal chow (blood glucose [BG] = 348 ± 30 vs. 126 ± 3; mg/dl; days 9 vs. 23 day, P < 0.01). After 18- and 28-day exposure to a HFD, damage was more severe and repair was less evident. Insulin levels progressively diminished with 9-day exposure to a HFD; after returning to a regular diet, insulin levels rebounded toward, but did not reach, normal values. Increase in β cell mass was 4-fold after 9 days and 3-fold after 18 days, and there was no increase after 28 days of a HFD. Increases in β cell mass during a HFD were not different when comparing values before and after a return to regular diet within the 9-, 18-, or 28-day studies. No changes were observed in apoptosis or β cell replication. Formation of intracellular markers of oxidative stress, intranuclear translocation of Nrf2, and formation of intracellular antioxidant proteins indicated the participation of HFD/oxidative stress induction of the Nrf2/antioxidant pathway. Flow cytometry-based assessment of β cell volume, morphology, and insulin-specific immunoreactivity, as well as ultrastructural analysis by transmission electron microscopy, revealed that short-term exposure to a HFD produced significant changes in β cell morphology and function that are reversible after returning to regular chow. These results suggest that a possible mechanism mediating the ability of β cells to self-repair after a short-term exposure to a HFD is the activation of the Nrf2/antioxidant pathway.
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Affiliation(s)
- Tsehay Abebe
- Pacific Northwest Diabetes Research Institute, Seattle, Washington, USA
| | - Jana Mahadevan
- Pacific Northwest Diabetes Research Institute, Seattle, Washington, USA.,Division of Metabolism, Endocrinology, and Nutrition, Department of Medicine, and.,Department of Pharmacology, University of Washington, Seattle, Washington, USA.,Department of Endocrinology, Metabolism, and Lipid Research, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Lindsey Bogachus
- Pacific Northwest Diabetes Research Institute, Seattle, Washington, USA.,Division of Metabolism, Endocrinology, and Nutrition, Department of Medicine, and.,Department of Pharmacology, University of Washington, Seattle, Washington, USA.,Division of Endocrinology and Metabolism, Department of Medicine, University of Minnesota, Minneapolis, Minnesota, USA
| | - Stephanie Hahn
- Pacific Northwest Diabetes Research Institute, Seattle, Washington, USA
| | - Michele Black
- Department of Immunology, University of Washington, Seattle, Washington, USA
| | - Elizabeth Oseid
- Pacific Northwest Diabetes Research Institute, Seattle, Washington, USA
| | - Fumihiko Urano
- Department of Endocrinology, Metabolism, and Lipid Research, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Vincenzo Cirulli
- Division of Metabolism, Endocrinology, and Nutrition, Department of Medicine, and.,Department of Pharmacology, University of Washington, Seattle, Washington, USA
| | - R Paul Robertson
- Pacific Northwest Diabetes Research Institute, Seattle, Washington, USA.,Division of Metabolism, Endocrinology, and Nutrition, Department of Medicine, and.,Department of Pharmacology, University of Washington, Seattle, Washington, USA.,Division of Endocrinology and Metabolism, Department of Medicine, University of Minnesota, Minneapolis, Minnesota, USA
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20
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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: 27] [Impact Index Per Article: 3.4] [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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21
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Sharp J, Vermette P. An In-situ
glucose-stimulated insulin secretion assay under perfusion bioreactor conditions. Biotechnol Prog 2016; 33:454-462. [DOI: 10.1002/btpr.2407] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Revised: 09/23/2016] [Indexed: 12/28/2022]
Affiliation(s)
- Jamie Sharp
- Laboratoire de bio-ingénierie et de biophysique de l'Université de Sherbrooke, Dept. of Chemical and Biotechnological Engineering; Université de Sherbrooke; 2500 boulevard de l'Université Sherbrooke QC J1K 2R1 Canada
| | - Patrick Vermette
- Laboratoire de bio-ingénierie et de biophysique de l'Université de Sherbrooke, Dept. of Chemical and Biotechnological Engineering; Université de Sherbrooke; 2500 boulevard de l'Université Sherbrooke QC J1K 2R1 Canada
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22
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Chang CC, Yuan W, Roan HY, Chang JL, Huang HC, Lee YC, Tsay HJ, Liu HK. The ethyl acetate fraction of corn silk exhibits dual antioxidant and anti-glycation activities and protects insulin-secreting cells from glucotoxicity. Altern Ther Health Med 2016; 16:432. [PMID: 27809830 PMCID: PMC5294807 DOI: 10.1186/s12906-016-1382-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Accepted: 10/07/2016] [Indexed: 11/10/2022]
Abstract
Background In this study, we aimed to develop a Stigmata Maydis (corn silk) fraction with dual bio-activities against oxidative stress and protein glycation to protect β-cells from diabetes-induced failure. Methods Corn silk fractions were prepared by partition and chemically characterised by thin-layer chromatography. Free radical scavenging assay, glycation assay, and cell-based viability test (neutral red) were employed to decide the best fraction. Cell death analysis was executed by annexin V/ Propidium iodide staining. Cell proliferation was measured by WST-1. Finally, β-cell function was evaluated by β-cell marker gene expression (RT-PCR) and acute insulin secretion test. Results Four corn silk fractions were prepared from an ethanolic crude extract of corn silk. In vitro assays indicate ethyl acetate fraction (YMS-EA) was the most potent fraction. YMS-EA also attenuated the hydrogen peroxide- or methylglyoxal-induced induction of reactive oxygen species, reduction of cell viability, and inhibition of cell proliferation. However, YMS-EA was unable to prevent hydrogen peroxide-induced apoptosis or advanced glycation end-products-induced toxicity. Under hyperglycemic conditions, YMS-EA effectively reduced ROS levels, improved mRNA expression of insulin, glucokinase, and PDX-1, and enhanced glucose-stimulated insulin secretion. The similarity of bioactivities among apigenin, luteolin, and YMS-EA indicated that dual activities of YMS-EA might be derived from those compounds. Conclusions We concluded that YMS-EA fraction could be developed as a preventive food agent against the glucotoxicity to β-cells in Type 2 diabetes.
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Duan H, Lee JW, Moon SW, Arora D, Li Y, Lim HY, Wang W. Discovery, Synthesis, and Evaluation of 2,4-Diaminoquinazolines as a Novel Class of Pancreatic β-Cell-Protective Agents against Endoplasmic Reticulum (ER) Stress. J Med Chem 2016; 59:7783-800. [PMID: 27505441 DOI: 10.1021/acs.jmedchem.6b00041] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Pancreatic insulin-producing β-cell dysfunction and death plays central roles in the onset and progression of both type 1 and type 2 diabetes. Current antidiabetic drugs cannot halt the ongoing progression of β-cell dysfunction and death. In diabetes, a major cause for the decline in β-cell function and survival is endoplasmic reticulum (ER) stress. Here, we identified quinazoline derivatives as a novel class of β-cell protective agents against ER stress-induced dysfunction and death. A series of quinazoline derivatives were synthesized from dichloroquiazoline utilizing a sequence of nucleophilic reactions. Through SAR optimization, 2,4-diaminoquinazoline compound 9c markedly protects β-cells against ER stress-induced dysfunction and death with 80% maximum rescue activity and an EC50 value of 0.56 μM. Importantly, 9c restores the ER stress-impaired glucose-stimulated insulin secretion response and survival in primary human islet β-cells. We showed that 9c protects β-cells by alleviating ER stress through the suppression of the induction of key genes of the unfolded protein response and apoptosis.
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Affiliation(s)
- Hongliang Duan
- Immunobiology and Cancer Program, Oklahoma Medical Research Foundation , 825 NE 13th Street, Oklahoma City, Oklahoma 73104, United States
| | - Jae Wook Lee
- Natural Product Research Center, Korea Institute of Science and Technology , 679 Saimdang-ro, Gangneung, Gangwon-do 210-340, Republic of Korea.,Department of Biological Chemistry, Korea University of Science and Technology (UST) , Daejeon 305-333, Republic of Korea
| | - Sung Won Moon
- Natural Product Research Center, Korea Institute of Science and Technology , 679 Saimdang-ro, Gangneung, Gangwon-do 210-340, Republic of Korea
| | - Daleep Arora
- Immunobiology and Cancer Program, Oklahoma Medical Research Foundation , 825 NE 13th Street, Oklahoma City, Oklahoma 73104, United States
| | - Yu Li
- Department of Medicine, Division of Endocrinology, Department of Physiology, Harold Hamm Diabetes Center, The University of Oklahoma Health Science Center , 941 Stanton L. Young Boulevard, Oklahoma City, Oklahoma 73104, United States
| | - Hui-Ying Lim
- Department of Physiology, The University of Oklahoma Health Science Center , 941 Stanton L. Young Boulevard, Oklahoma City, Oklahoma 73104, United States
| | - Weidong Wang
- Immunobiology and Cancer Program, Oklahoma Medical Research Foundation , 825 NE 13th Street, Oklahoma City, Oklahoma 73104, United States.,Department of Medicine, Division of Endocrinology, Department of Physiology, Harold Hamm Diabetes Center, The University of Oklahoma Health Science Center , 941 Stanton L. Young Boulevard, Oklahoma City, Oklahoma 73104, United States
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The Effects of Empagliflozin, an SGLT2 Inhibitor, on Pancreatic β-Cell Mass and Glucose Homeostasis in Type 1 Diabetes. PLoS One 2016; 11:e0147391. [PMID: 26807719 PMCID: PMC4726656 DOI: 10.1371/journal.pone.0147391] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Accepted: 01/04/2016] [Indexed: 12/25/2022] Open
Abstract
The novel sodium glucose co-transporter 2 (SGLT2) inhibitor empagliflozin has recently been reported to improve glycemic control in streptozotocin-induced type 1 diabetic rats in an insulin-independent manner, via an increase in urinary glucose output. We investigated the potential of empagliflozin to recover insulin pathways in type 1 diabetes by improving pancreatic β-cell mass. Blood glucose homeostasis was assessed by an intraperitoneal glucose tolerance test. Serum insulin levels and insulin mRNA expression were determined using commercial insulin ELISA kits and real-time quantitative polymerase chain reaction, respectively. Immunohistochemistry was used to investigate β-cell areas, β-cell proliferation, apoptosis of pancreatic β-cells, and reactive oxygen species production in the pancreatic β-cells. Results showed that glucose tolerance was significantly improved in streptozotocin-induced type 1 diabetic mice treated with empagliflozin. Empagliflozin-treated mice also showed an increase in insulin mRNA expression. Higher serum insulin levels were detected in mice treated with empagliflozin compared with the vehicle group. Immunohistochemistry indicated that β-cell area/total pancreatic area and the expression of cell proliferation marker Ki-67 (co-stained with insulin) were significantly enhanced by empagliflozin treatment. These effects were due, probably, to a reduction in apoptosis and reactive oxygen species in the pancreatic β-cells. Taken together, the results of this study indicate that empagliflozin may have a beneficial effect on preserving β-cell regeneration, thus improving blood glucose homeostasis in type 1 diabetes mellitus, probably via the protection of pancreatic β-cell from glucotoxicity-induced oxidative stress.
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Nomoto H, Kondo T, Miyoshi H, Nakamura A, Hida Y, Yamashita KI, Sharma AJ, Atsumi T. Inhibition of Small Maf Function in Pancreatic β-Cells Improves Glucose Tolerance Through the Enhancement of Insulin Gene Transcription and Insulin Secretion. Endocrinology 2015; 156:3570-80. [PMID: 25763640 PMCID: PMC4588816 DOI: 10.1210/en.2014-1906] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The large-Maf transcription factor v-maf musculoaponeurotic fibrosarcoma oncogene homolog A (MafA) has been found to be crucial for insulin transcription and synthesis and for pancreatic β-cell function and maturation. However, insights about the effects of small Maf factors on β-cells are limited. Our goal was to elucidate the function of small-Maf factors on β-cells using an animal model of endogenous small-Maf dysfunction. Transgenic (Tg) mice with β-cell-specific expression of dominant-negative MafK (DN-MafK) experiments, which can suppress the function of all endogenous small-Mafs, were fed a high-fat diet, and their in vivo phenotypes were evaluated. Phenotypic analysis, glucose tolerance tests, morphologic examination of β-cells, and islet experiments were performed. DN-MafK-expressed MIN6 cells were also used for in vitro analysis. The results showed that DN-MafK expression inhibited endogenous small-Maf binding to insulin promoter while increasing MafA binding. DN-MafK Tg mice under high-fat diet conditions showed improved glucose metabolism compared with control mice via incremental insulin secretion, without causing changes in insulin sensitivity or MafA expression. Moreover, up-regulation of insulin and glucokinase gene expression was observed both in vivo and in vitro under DN-MafK expression. We concluded that endogenous small-Maf factors negatively regulates β-cell function by competing for MafA binding, and thus, the inhibition of small-Maf activity can improve β-cell function.
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Affiliation(s)
- Hiroshi Nomoto
- Division of Rheumatology, Endocrinology and Nephrology (H.N., T.K., H.M., A.N., Y.H., T.A.), and Department of Transplant Surgery (K.Y.), Hokkaido University Graduate School of Medicine, Sapporo, Japan 060-8638; Section of Islet Transplantation and Cell Biology (A.J.S.), Joslin Diabetes Center, Boston, Massachusetts 02215; and MedImmune LLC (A.J.S.), Gaithersburg, Maryland 20878
| | - Takuma Kondo
- Division of Rheumatology, Endocrinology and Nephrology (H.N., T.K., H.M., A.N., Y.H., T.A.), and Department of Transplant Surgery (K.Y.), Hokkaido University Graduate School of Medicine, Sapporo, Japan 060-8638; Section of Islet Transplantation and Cell Biology (A.J.S.), Joslin Diabetes Center, Boston, Massachusetts 02215; and MedImmune LLC (A.J.S.), Gaithersburg, Maryland 20878
| | - Hideaki Miyoshi
- Division of Rheumatology, Endocrinology and Nephrology (H.N., T.K., H.M., A.N., Y.H., T.A.), and Department of Transplant Surgery (K.Y.), Hokkaido University Graduate School of Medicine, Sapporo, Japan 060-8638; Section of Islet Transplantation and Cell Biology (A.J.S.), Joslin Diabetes Center, Boston, Massachusetts 02215; and MedImmune LLC (A.J.S.), Gaithersburg, Maryland 20878
| | - Akinobu Nakamura
- Division of Rheumatology, Endocrinology and Nephrology (H.N., T.K., H.M., A.N., Y.H., T.A.), and Department of Transplant Surgery (K.Y.), Hokkaido University Graduate School of Medicine, Sapporo, Japan 060-8638; Section of Islet Transplantation and Cell Biology (A.J.S.), Joslin Diabetes Center, Boston, Massachusetts 02215; and MedImmune LLC (A.J.S.), Gaithersburg, Maryland 20878
| | - Yoko Hida
- Division of Rheumatology, Endocrinology and Nephrology (H.N., T.K., H.M., A.N., Y.H., T.A.), and Department of Transplant Surgery (K.Y.), Hokkaido University Graduate School of Medicine, Sapporo, Japan 060-8638; Section of Islet Transplantation and Cell Biology (A.J.S.), Joslin Diabetes Center, Boston, Massachusetts 02215; and MedImmune LLC (A.J.S.), Gaithersburg, Maryland 20878
| | - Ken-ichiro Yamashita
- Division of Rheumatology, Endocrinology and Nephrology (H.N., T.K., H.M., A.N., Y.H., T.A.), and Department of Transplant Surgery (K.Y.), Hokkaido University Graduate School of Medicine, Sapporo, Japan 060-8638; Section of Islet Transplantation and Cell Biology (A.J.S.), Joslin Diabetes Center, Boston, Massachusetts 02215; and MedImmune LLC (A.J.S.), Gaithersburg, Maryland 20878
| | - Arun J Sharma
- Division of Rheumatology, Endocrinology and Nephrology (H.N., T.K., H.M., A.N., Y.H., T.A.), and Department of Transplant Surgery (K.Y.), Hokkaido University Graduate School of Medicine, Sapporo, Japan 060-8638; Section of Islet Transplantation and Cell Biology (A.J.S.), Joslin Diabetes Center, Boston, Massachusetts 02215; and MedImmune LLC (A.J.S.), Gaithersburg, Maryland 20878
| | - Tatsuya Atsumi
- Division of Rheumatology, Endocrinology and Nephrology (H.N., T.K., H.M., A.N., Y.H., T.A.), and Department of Transplant Surgery (K.Y.), Hokkaido University Graduate School of Medicine, Sapporo, Japan 060-8638; Section of Islet Transplantation and Cell Biology (A.J.S.), Joslin Diabetes Center, Boston, Massachusetts 02215; and MedImmune LLC (A.J.S.), Gaithersburg, Maryland 20878
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Park JH, Cho KI, Nam H, Choe NH, Suh JG. Anti-apoptotic effects of silk fibroin hydrolysate in RIN5F cell on high glucose condition. Anim Cells Syst (Seoul) 2015. [DOI: 10.1080/19768354.2015.1042045] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
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27
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Zhou G, Sinnett-Smith J, Liu SH, Yu J, Wu J, Sanchez R, Pandol SJ, Abrol R, Nemunaitis J, Rozengurt E, Brunicardi FC. Down-regulation of pancreatic and duodenal homeobox-1 by somatostatin receptor subtype 5: a novel mechanism for inhibition of cellular proliferation and insulin secretion by somatostatin. Front Physiol 2014; 5:226. [PMID: 25009500 PMCID: PMC4069483 DOI: 10.3389/fphys.2014.00226] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Accepted: 05/31/2014] [Indexed: 01/29/2023] Open
Abstract
Somatostatin (SST) is a regulatory peptide and acts as an endogenous inhibitory regulator of the secretory and proliferative responses of target cells. SST’s actions are mediated by a family of seven transmembrane domain G protein-coupled receptors that comprise five distinct subtypes (SSTR1-5). SSTR5 is one of the major SSTRs in the islets of Langerhans. Homeodomain-containing transcription factor pancreatic and duodenal homeobox-1 (PDX-1) is essential for pancreatic development, β cell differentiation, maintenance of normal β cell functions in adults and tumorigenesis. Recent studies show that SSTR5 acts as a negative regulator for PDX-1 expression and that SSTR5 mediates somatostatin’s inhibitory effect on cell proliferation and insulin expression/excretion through down-regulating PDX-1 expression. SSTR5 exerts its inhibitory effect on PDX-1 expression at both the transcriptional level by down-regulating PDX-1 mRNA and the post-translational level by enhancing PDX-1 ubiquitination. Identification of PDX-1 as a transcriptional target for SSTR5 may help in guiding the choice of therapeutic cancer treatments.
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Affiliation(s)
- Guisheng Zhou
- Division of General Surgery, Department of Surgery, David Geffen School of Medicine at University of California Los Angeles, CA, USA ; CURE: Digestive Disease Research Center, David Geffen School of Medicine at University of California Los Angeles, CA, USA
| | - Jim Sinnett-Smith
- CURE: Digestive Disease Research Center, David Geffen School of Medicine at University of California Los Angeles, CA, USA ; Department of Medicine, David Geffen School of Medicine at University of California Los Angeles, CA, USA
| | - Shi-He Liu
- Division of General Surgery, Department of Surgery, David Geffen School of Medicine at University of California Los Angeles, CA, USA
| | - Juehua Yu
- Division of General Surgery, Department of Surgery, David Geffen School of Medicine at University of California Los Angeles, CA, USA
| | - James Wu
- Division of General Surgery, Department of Surgery, David Geffen School of Medicine at University of California Los Angeles, CA, USA
| | - Robbi Sanchez
- Division of General Surgery, Department of Surgery, David Geffen School of Medicine at University of California Los Angeles, CA, USA
| | - Stephen J Pandol
- CURE: Digestive Disease Research Center, David Geffen School of Medicine at University of California Los Angeles, CA, USA ; Department of Medicine at Cedars Sinai Medical Center Los Angeles, CA, USA ; Veterans Affairs Los Angeles, CA, USA
| | - Ravinder Abrol
- Materials and Process Simulation Center, California Institute of Technology Pasadena, CA, USA
| | - John Nemunaitis
- Gradalis, Inc., Dallas, TX, USA ; Mary Crowley Cancer Research Centers Dallas, TX, USA
| | - Enrique Rozengurt
- CURE: Digestive Disease Research Center, David Geffen School of Medicine at University of California Los Angeles, CA, USA ; Department of Medicine, David Geffen School of Medicine at University of California Los Angeles, CA, USA
| | - F Charles Brunicardi
- Division of General Surgery, Department of Surgery, David Geffen School of Medicine at University of California Los Angeles, CA, USA ; CURE: Digestive Disease Research Center, David Geffen School of Medicine at University of California Los Angeles, CA, USA
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Abstract
Over 200 million people worldwide suffer from diabetes, a disorder of glucose homeostasis. The majority of these individuals are diagnosed with type 2 diabetes. It has traditionally been thought that tissue resistance to the action of insulin is the primary defect in type 2 diabetes. However, recent longitudinal and genome‐wide association studies have shown that insulin resistance is more likely to be a precondition, and that the failure of the pancreatic β cell to meet the increased insulin requirements is the triggering factor in the development of type 2 diabetes. A major emphasis in diabetes research has therefore shifted to understanding the causes of β cell failure. Collectively, these studies have implicated a complex network of triggers, which activate intersecting execution pathways leading to β cell dysfunction and death. In the present review, we discuss these triggers (glucotoxicity, lipotoxicity, amyloid and cytokines) with respect to the pathways they activate (oxidative stress, inflammation and endoplasmic reticulum stress) and propose a model for understanding β cell failure in type 2 diabetes. (J Diabetes Invest, doi: 10.1111/j.2040‐1124.2010.00021.x, 2010)
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Affiliation(s)
- Takeshi Ogihara
- Department of Pediatrics and the Herman B Wells Center for Pediatric Research
| | - Raghavendra G Mirmira
- Department of Pediatrics and the Herman B Wells Center for Pediatric Research ; Departments of Medicine and Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, IN, USA
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29
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Park JH, Shim HM, Na AY, Bae KC, Bae JH, Im SS, Cho HC, Song DK. Melatonin prevents pancreatic β-cell loss due to glucotoxicity: the relationship between oxidative stress and endoplasmic reticulum stress. J Pineal Res 2014; 56:143-53. [PMID: 24168371 DOI: 10.1111/jpi.12106] [Citation(s) in RCA: 27] [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: 08/22/2013] [Accepted: 10/25/2013] [Indexed: 12/31/2022]
Abstract
Prolonged hyperglycemia results in pancreatic β-cell dysfunction and apoptosis, referred to as glucotoxicity. Although both oxidative and endoplasmic reticulum (ER) stresses have been implicated as major causative mechanisms of β-cell glucotoxicity, the reciprocal importance between the two remains to be elucidated. The aim of this study was to evaluate the differential effect of oxidative stress and ER stress on β-cell glucotoxicity, by employing melatonin which has free radical-scavenging and antioxidant properties. As expected, in β-cells exposed to prolonged high glucose levels, cell viability and glucose-stimulated insulin secretion (GSIS) were significantly impaired. Melatonin treatment markedly attenuated cellular apoptosis by scavenging reactive oxygen species via its plasmalemmal receptor-independent increase in antioxidant enzyme activity. However, treatments with antioxidants alone were insufficient to recover the impaired GSIS. Interestingly, 4-phenylbutyric acid (4-PBA), a chemical chaperone that attenuate ER stress by stabilizing protein structure, alleviated the impaired GSIS, but not apoptosis, suggesting that glucotoxicity induces oxidative and ER stress independently. We found that cotreatment of glucotoxic β-cells with melatonin and 4-PBA dramatically improved both their survival and insulin secretion. Taken together, these results suggest that ER stress may be the more critical mechanism for prolonged high-glucose-induced GSIS impairment, whereas oxidative stress appears to be more critical for the impaired β-cell viability. Therefore, combinatorial therapy of melatonin with an ER stress modifier may help recover pancreatic β-cells under glucotoxic conditions in type 2 diabetes.
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Affiliation(s)
- Jae-Hyung Park
- Department of Physiology, Keimyung University School of Medicine, Daegu, Korea
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30
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Arya VB, Rahman S, Senniappan S, Flanagan SE, Ellard S, Hussain K. HNF4A mutation: switch from hyperinsulinaemic hypoglycaemia to maturity-onset diabetes of the young, and incretin response. Diabet Med 2014; 31:e11-5. [PMID: 24299156 PMCID: PMC4305198 DOI: 10.1111/dme.12369] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2013] [Revised: 09/17/2013] [Accepted: 11/28/2013] [Indexed: 12/19/2022]
Abstract
BACKGROUND Hepatocyte nuclear factor 4α (HNF4A) is a member of the nuclear receptor family of ligand-activated transcription factors. HNF4A mutations cause hyperinsulinaemic hypoglycaemia in early life and maturity-onset diabetes of the young. Regular screening of HNF4A mutation carriers using the oral glucose tolerance test has been recommended to diagnose diabetes mellitus at an early stage. Glucagon-like peptide-1 and glucose-dependent insulinotropic polypeptide are incretin hormones, responsible for up to 70% of the secreted insulin after a meal in healthy individuals. We describe, for the first time, gradual alteration of glucose homeostasis in a patient with HNF4A mutation after resolution of hyperinsulinaemic hypoglycaemia, on serial oral glucose tolerance testing. We also measured the incretin response to a mixed meal in our patient. CASE REPORT Our patient was born with macrosomia and developed hyperinsulinaemic hypoglycaemia in the neonatal period. Molecular genetic analysis confirmed HNF4A mutation (p.M116I, c.317G>A) as an underlying cause of hyperinsulinaemic hypoglycaemia. Serial oral glucose tolerance testing, after the resolution of hyperinsulinaemic hypoglycaemia, confirmed the diagnosis of maturity-onset diabetes of the young at the age of 10 years. Interestingly, the intravenous glucose tolerance test revealed normal glucose disappearance rate and first-phase insulin secretion. Incretin hormones showed a suboptimal rise in response to the mixed meal, potentially explaining the discrepancy between the oral glucose tolerance test and the intravenous glucose tolerance test. CONCLUSIONS Maturity-onset diabetes of the young can develop as early as the first decade of life in persons with an HNF4A mutation. Impaired incretin response might be contributory in the early stages of HNF4A maturity-onset diabetes of the young.
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Affiliation(s)
- V B Arya
- Department of Paediatric Endocrinology, Great Ormond Street Hospital for Children NHSTrust, London
- The Institute of Child Health, University College LondonExeter, UK
| | - S Rahman
- The Institute of Child Health, University College LondonExeter, UK
| | - S Senniappan
- Department of Paediatric Endocrinology, Great Ormond Street Hospital for Children NHSTrust, London
- The Institute of Child Health, University College LondonExeter, UK
| | - S E Flanagan
- Institute of Biomedical and Clinical Science, University of Exeter Medical SchoolExeter, UK
| | - S Ellard
- Institute of Biomedical and Clinical Science, University of Exeter Medical SchoolExeter, UK
| | - K Hussain
- Department of Paediatric Endocrinology, Great Ormond Street Hospital for Children NHSTrust, London
- The Institute of Child Health, University College LondonExeter, UK
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31
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Mahadevan J, Parazzoli S, Oseid E, Hertzel AV, Bernlohr DA, Vallerie SN, Liu CQ, Lopez M, Harmon JS, Robertson RP. Ebselen treatment prevents islet apoptosis, maintains intranuclear Pdx-1 and MafA levels, and preserves β-cell mass and function in ZDF rats. Diabetes 2013; 62:3582-8. [PMID: 23801580 PMCID: PMC3781455 DOI: 10.2337/db13-0357] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
We reported earlier that β-cell-specific overexpression of glutathione peroxidase (GPx)-1 significantly ameliorated hyperglycemia in diabetic db/db mice and prevented glucotoxicity-induced deterioration of β-cell mass and function. We have now ascertained whether early treatment of Zucker diabetic fatty (ZDF) rats with ebselen, an oral GPx mimetic, will prevent β-cell deterioration. No other antihyperglycemic treatment was given. Ebselen ameliorated fasting hyperglycemia, sustained nonfasting insulin levels, lowered nonfasting glucose levels, and lowered HbA1c levels with no effects on body weight. Ebselen doubled β-cell mass, prevented apoptosis, prevented expression of oxidative stress markers, and enhanced intranuclear localization of pancreatic and duodenal homeobox (Pdx)-1 and v-maf musculoaponeurotic fibrosarcoma oncogene family, protein A (MafA), two critical insulin transcription factors. Minimal β-cell replication was observed in both groups. These findings indicate that prevention of oxidative stress is the mechanism whereby ebselen prevents apoptosis and preserves intranuclear Pdx-1 and MafA, which, in turn, is a likely explanation for the beneficial effects of ebselen on β-cell mass and function. Since ebselen is an oral antioxidant currently used in clinical trials, it is a novel therapeutic candidate to ameliorate fasting hyperglycemia and further deterioration of β-cell mass and function in humans undergoing the onset of type 2 diabetes.
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Affiliation(s)
- Jana Mahadevan
- Pacific Northwest Diabetes Research Institute and Division of Metabolism, Endocrinology, and Nutrition, University of Washington, Seattle, Washington
| | - Susan Parazzoli
- Pacific Northwest Diabetes Research Institute and Division of Metabolism, Endocrinology, and Nutrition, University of Washington, Seattle, Washington
| | - Elizabeth Oseid
- Pacific Northwest Diabetes Research Institute and Division of Metabolism, Endocrinology, and Nutrition, University of Washington, Seattle, Washington
| | - Ann V. Hertzel
- Department of Biochemistry and Molecular Biology, University of Minnesota, Minneapolis, Minnesota
| | - David A. Bernlohr
- Department of Biochemistry and Molecular Biology, University of Minnesota, Minneapolis, Minnesota
| | - Sara N. Vallerie
- Pacific Northwest Diabetes Research Institute and Division of Metabolism, Endocrinology, and Nutrition, University of Washington, Seattle, Washington
| | - Chang-qin Liu
- Pacific Northwest Diabetes Research Institute and Division of Metabolism, Endocrinology, and Nutrition, University of Washington, Seattle, Washington
| | - Melissa Lopez
- Pacific Northwest Diabetes Research Institute and Division of Metabolism, Endocrinology, and Nutrition, University of Washington, Seattle, Washington
| | - Jamie S. Harmon
- Pacific Northwest Diabetes Research Institute and Division of Metabolism, Endocrinology, and Nutrition, University of Washington, Seattle, Washington
| | - R. Paul Robertson
- Pacific Northwest Diabetes Research Institute and Division of Metabolism, Endocrinology, and Nutrition, University of Washington, Seattle, Washington
- Department of Biochemistry and Molecular Biology, University of Minnesota, Minneapolis, Minnesota
- Corresponding author: R. Paul Robertson,
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32
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Deshmukh AB, Patel MC, Mishra B. SGLT2 inhibition: a novel prospective strategy in treatment of diabetes mellitus. Ren Fail 2013; 35:566-72. [PMID: 23438184 DOI: 10.3109/0886022x.2013.766560] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The role of the kidney in glucose homeostasis and the potential of the kidney as a therapeutic target in type 2 diabetes is little appreciated. Hyperglycemia is an important pathogenic component in the development of microvascular and macrovascular complications in type 2 diabetes mellitus. Inhibition of renal tubular glucose re-absorption that leads to glycosuria has been proposed as a new mechanism to attain normoglycemia and thus prevent and diminish these complications, thus representing an innovative therapeutic strategy for the treatment of hyperglycemia and/or obesity in patients with type 1 or type 2 diabetes by enhancing glucose and energy loss through the urine. Sodium glucose co-transporter 2 (SGLT2) has a key role in re-absorption of glucose in kidney. Competitive inhibitors of SGLT2 have been discovered and a few of them have also been advanced in clinical trials for the treatment of diabetes.
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Affiliation(s)
- Aaishwarya B Deshmukh
- Department of Pharmacology, Shankersinh Vaghela Bapu Institute of Pharmacy, Gujarat, India
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33
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Abstract
Pancreatic β-cell dysfunction plays an important role in the pathogenesis of both type 1 and type 2 diabetes. Insulin, which is produced in β-cells, is a critical regulator of metabolism. Insulin is synthesized as preproinsulin and processed to proinsulin. Proinsulin is then converted to insulin and C-peptide and stored in secretary granules awaiting release on demand. Insulin synthesis is regulated at both the transcriptional and translational level. The cis-acting sequences within the 5' flanking region and trans-activators including paired box gene 6 (PAX6), pancreatic and duodenal homeobox- 1(PDX-1), MafA, and β-2/Neurogenic differentiation 1 (NeuroD1) regulate insulin transcription, while the stability of preproinsulin mRNA and its untranslated regions control protein translation. Insulin secretion involves a sequence of events in β-cells that lead to fusion of secretory granules with the plasma membrane. Insulin is secreted primarily in response to glucose, while other nutrients such as free fatty acids and amino acids can augment glucose-induced insulin secretion. In addition, various hormones, such as melatonin, estrogen, leptin, growth hormone, and glucagon like peptide-1 also regulate insulin secretion. Thus, the β-cell is a metabolic hub in the body, connecting nutrient metabolism and the endocrine system. Although an increase in intracellular [Ca2+] is the primary insulin secretary signal, cAMP signaling- dependent mechanisms are also critical in the regulation of insulin secretion. This article reviews current knowledge on how β-cells synthesize and secrete insulin. In addition, this review presents evidence that genetic and environmental factors can lead to hyperglycemia, dyslipidemia, inflammation, and autoimmunity, resulting in β-cell dysfunction, thereby triggering the pathogenesis of diabetes.
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Affiliation(s)
- Zhuo Fu
- Department of Human Nutrition, Foods and Exercise, Virginia Tech, Blacksburg, VA 24061, USA
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34
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Fu Z, Gilbert ER, Liu D. Regulation of insulin synthesis and secretion and pancreatic Beta-cell dysfunction in diabetes. Curr Diabetes Rev 2013; 9:25-53. [PMID: 22974359 PMCID: PMC3934755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/06/2012] [Revised: 09/11/2012] [Accepted: 09/11/2012] [Indexed: 11/11/2023]
Abstract
Pancreatic β-cell dysfunction plays an important role in the pathogenesis of both type 1 and type 2 diabetes. Insulin, which is produced in β-cells, is a critical regulator of metabolism. Insulin is synthesized as preproinsulin and processed to proinsulin. Proinsulin is then converted to insulin and C-peptide and stored in secretary granules awaiting release on demand. Insulin synthesis is regulated at both the transcriptional and translational level. The cis-acting sequences within the 5' flanking region and trans-activators including paired box gene 6 (PAX6), pancreatic and duodenal homeobox- 1(PDX-1), MafA, and β-2/Neurogenic differentiation 1 (NeuroD1) regulate insulin transcription, while the stability of preproinsulin mRNA and its untranslated regions control protein translation. Insulin secretion involves a sequence of events in β-cells that lead to fusion of secretory granules with the plasma membrane. Insulin is secreted primarily in response to glucose, while other nutrients such as free fatty acids and amino acids can augment glucose-induced insulin secretion. In addition, various hormones, such as melatonin, estrogen, leptin, growth hormone, and glucagon like peptide-1 also regulate insulin secretion. Thus, the β-cell is a metabolic hub in the body, connecting nutrient metabolism and the endocrine system. Although an increase in intracellular [Ca2+] is the primary insulin secretary signal, cAMP signaling- dependent mechanisms are also critical in the regulation of insulin secretion. This article reviews current knowledge on how β-cells synthesize and secrete insulin. In addition, this review presents evidence that genetic and environmental factors can lead to hyperglycemia, dyslipidemia, inflammation, and autoimmunity, resulting in β-cell dysfunction, thereby triggering the pathogenesis of diabetes.
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Affiliation(s)
- Zhuo Fu
- Department of Human Nutrition, Foods and Exercise, Virginia Tech, Blacksburg, VA 24061, USA
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Batumalaie K, Zaman Safi S, Mohd Yusof K, Shah Ismail I, Devi Sekaran S, Qvist R. Effect of gelam honey on the oxidative stress-induced signaling pathways in pancreatic hamster cells. Int J Endocrinol 2013; 2013:367312. [PMID: 24324490 PMCID: PMC3845241 DOI: 10.1155/2013/367312] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2013] [Revised: 09/21/2013] [Accepted: 10/05/2013] [Indexed: 12/27/2022] Open
Abstract
Background. Oxidative stress induced by reactive oxygen and nitrogen species is critically involved in the impairment of β -cell function during the development of diabetes. Methods. HIT-T15 cells were cultured in 5% CO2 and then preincubated with Gelam honey extracts (20, 40, 60, and 80 µg/mL) as well as quercetin (20, 40, 60, and 80 µM), prior to stimulation by 20 and 50 mM of glucose. Cell lysate was collected to determine the effect of honey extracts and quercetin on the stress activated NF- κ B, MAPK pathways, and the Akt (ser473) activated insulin signaling pathway. Results. HIT-T15 cells cultured under hyperglycemic conditions demonstrated insulin resistance with a significant increase in the levels of MAPK, NF- κ B, and IRS-1 serine phosphorylation (ser307); however, Akt expression and insulin contents are significantly decreased. Pretreatment with quercetin and Gelam honey extract improved insulin resistance and insulin content by reducing the expression of MAPK, NF- κ B, and IRS-1 serine phosphorylation (ser307) and increasing the expression of Akt significantly. Conclusion. Gelam honey-induced differential expression of MAPK, NF- κ B, IRS-1 (ser307), and Akt in HIT-T15 cells shows that Gelam honey exerts protective effects against diabetes- and hyperglycemia-induced oxidative stress by improving insulin content and insulin resistance.
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Affiliation(s)
- Kalaivani Batumalaie
- Department of Medicine, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia
- *Kalaivani Batumalaie:
| | - Sher Zaman Safi
- Department of Medicine, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Kamaruddin Mohd Yusof
- Department of Molecular Biology and Genetics, Faculty of Arts and Science, Canik Basari University, Samsun, Turkey
| | - Ikram Shah Ismail
- Department of Medicine, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Shamala Devi Sekaran
- Department of Microbiology, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Rajes Qvist
- Department of Medicine, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia
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Scharfmann R, Rachdi L, Ravassard P. Concise review: in search of unlimited sources of functional human pancreatic beta cells. Stem Cells Transl Med 2012; 2:61-7. [PMID: 23283495 DOI: 10.5966/sctm.2012-0120] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
It is well-established that insulin-producing pancreatic beta cells are central in diabetes. In type 1 diabetes, beta cells are destroyed by an autoimmune mechanism, whereas in type 2 diabetes, there is a decrease in functional beta-cell mass. In this context, studying beta cells is of major importance. Beta cells represent only 1% of total pancreatic cells and are found dispersed in the pancreatic gland. During the past decades, many tools and approaches have been developed to study rodent beta cells that efficiently pushed the field forward. However, rodent and human beta cells are not identical, and our knowledge of human beta cells has not progressed as quickly as our understanding of rodent beta cells. We believe that one of the reasons for this inefficient progress is the difficulty of accessing unlimited sources of functional human pancreatic beta cells. The main focus of this review concerns recent strategies to generate new sources of human pancreatic beta cells.
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Stojanovic I, Saksida T, Timotijevic G, Sandler S, Stosic-Grujicic S. Macrophage migration inhibitory factor (MIF) enhances palmitic acid- and glucose-induced murine beta cell dysfunction and destruction in vitro. Growth Factors 2012; 30:385-93. [PMID: 23137174 DOI: 10.3109/08977194.2012.734506] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Although several reports suggest a potentially deleterious role of macrophage migration inhibitory factor (MIF) in type 2 diabetes (T2D) pathology, it is still unclear how this pro-inflammatory cytokine acts on pancreatic beta cells. The aim of the present study was to evaluate MIF effects on murine beta cells in the in vitro settings mimicking T2D-associated conditions. Results indicate that recombinant MIF further increased apoptosis of pancreatic islets or MIN6 cells upon exposure to palmitic acid or glucose. This was accompanied by upregulation of several pro-apoptotic molecules. Furthermore, MIF potentiated nutrient-induced islet cell dysfunction, as revealed by lower glucose oxidation rate, ATP content, and depolarized mitochondrial membrane. The final outcome was potentiation of mitochondrial apoptotic pathway. The observed upregulation of nutrient-induced islet cell dysfunction and apoptosis by MIF implicates that silencing MIF may be beneficial for maintaining integrity of endocrine pancreas in obesity-associated T2D.
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Affiliation(s)
- Ivana Stojanovic
- Department of Immunology, Institute for Biological Research "Sinisa Stankovic", University of Belgrade, Serbia.
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Yang Y, Chang BHJ, Chan L. Sustained expression of the transcription factor GLIS3 is required for normal beta cell function in adults. EMBO Mol Med 2012. [PMID: 23197416 PMCID: PMC3569656 DOI: 10.1002/emmm.201201398] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Genome-wide association studies identified GLIS3 as a susceptibility locus for type 1 and type 2 diabetes. Global Glis3 deficiency in mice leads to congenital diabetes and neonatal lethality. In this study, we explore the role of Glis3 in adulthood using Glis3+/− and conditional knockout animals. We challenged Glis3+/− mice with high fat diet for 20 weeks and found that they developed diabetes because of impaired beta cell mass expansion. GLIS3 controls beta cell proliferation in response to high-fat feeding at least partly by regulating Ccnd2 transcription. To determine if sustained Glis3 expression is essential to normal beta cell function, we generated Glis3fl/fl/Pdx1CreERT+ animal by intercrossing Glis3fl/fl mice with Pdx1CreERT+ mice and used tamoxifen (TAM) to induce Glis3 deletion in adults. Adult Glis3fl/fl/Pdx1CreERT+ mice are euglycaemic. TAM-mediated beta cell-specific inactivation of Glis3 in adult mice downregulates insulin expression, leading to hyperglycaemia and subsequently enhanced beta cell apoptosis. We conclude that normal Glis3 expression is required for pancreatic beta cell function and mass maintenance during adulthood, which impairment leads to diabetes in adults.
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Affiliation(s)
- Yisheng Yang
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Diabetes and Endocrinology Research Center, Baylor College of Medicine, Houston, TX, USA
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39
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Bensellam M, Laybutt DR, Jonas JC. The molecular mechanisms of pancreatic β-cell glucotoxicity: recent findings and future research directions. Mol Cell Endocrinol 2012; 364:1-27. [PMID: 22885162 DOI: 10.1016/j.mce.2012.08.003] [Citation(s) in RCA: 208] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Revised: 07/11/2012] [Accepted: 08/01/2012] [Indexed: 02/06/2023]
Abstract
It is well established that regular physiological stimulation by glucose plays a crucial role in the maintenance of the β-cell differentiated phenotype. In contrast, prolonged or repeated exposure to elevated glucose concentrations both in vitro and in vivo exerts deleterious or toxic effects on the β-cell phenotype, a concept termed as glucotoxicity. Evidence indicates that the latter may greatly contribute to the pathogenesis of type 2 diabetes. Through the activation of several mechanisms and signaling pathways, high glucose levels exert deleterious effects on β-cell function and survival and thereby, lead to the worsening of the disease over time. While the role of high glucose-induced β-cell overstimulation, oxidative stress, excessive Unfolded Protein Response (UPR) activation, and loss of differentiation in the alteration of the β-cell phenotype is well ascertained, at least in vitro and in animal models of type 2 diabetes, the role of other mechanisms such as inflammation, O-GlcNacylation, PKC activation, and amyloidogenesis requires further confirmation. On the other hand, protein glycation is an emerging mechanism that may play an important role in the glucotoxic deterioration of the β-cell phenotype. Finally, our recent evidence suggests that hypoxia may also be a new mechanism of β-cell glucotoxicity. Deciphering these molecular mechanisms of β-cell glucotoxicity is a mandatory first step toward the development of therapeutic strategies to protect β-cells and improve the functional β-cell mass in type 2 diabetes.
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Affiliation(s)
- Mohammed Bensellam
- Université catholique de Louvain, Institut de recherche expérimentale et clinique, Pôle d'endocrinologie, diabète et nutrition, Brussels, Belgium
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40
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Abstract
Type 2 diabetes is characterized by pancreatic β-cell dysfunction and insulin resistance, and the number of patients has markedly increased worldwide. In the diabetic state, hyperglycemia per se and subsequent induction of oxidative stress decrease insulin biosynthesis and secretion, leading to the aggravation of Type 2 diabetes. In addition, there is substantial reduction in expression and/or activities of several insulin gene transcription factors. This process is known as β-cell glucose toxicity, which is often observed under diabetic conditions. Taken together, it is likely that oxidative stress explains, at least in part, the molecular mechanism for β-cell glucose toxicity, which is often observed in Type 2 diabetes.
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Yeo RWY, Yang K, Li G, Lim SK. High glucose predisposes gene expression and ERK phosphorylation to apoptosis and impaired glucose-stimulated insulin secretion via the cytoskeleton. PLoS One 2012; 7:e44988. [PMID: 23024780 PMCID: PMC3443235 DOI: 10.1371/journal.pone.0044988] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2012] [Accepted: 08/11/2012] [Indexed: 01/09/2023] Open
Abstract
Chronic high glucose (HG) inflicts glucotoxicity on vulnerable cell types such as pancreatic β cells and contributes to insulin resistance and impaired insulin secretion in diabetic patients. To identify HG-induced cellular aberrations that are candidate mediators of glucotoxicity in pancreatic β cells, we analyzed gene expression in ERoSHK6, a mouse insulin-secreting cell line after chronic HG exposure (six-day exposure to 33.3 mM glucose). Chronic HG exposure which reduced glucose-stimulated insulin secretion (GSIS) increased transcript levels of 185 genes that clustered primarily in 5 processes namely cellular growth and proliferation; cell death; cellular assembly and organization; cell morphology; and cell-to-cell signaling and interaction. The former two were validated by increased apoptosis of ERoSHK6 cells after chronic HG exposure and reaffirmed the vulnerability of β cells to glucotoxicity. The three remaining processes were partially substantiated by changes in cellular morphology and structure, and instigated an investigation of the cytoskeleton and cell-cell adhesion. These studies revealed a depolymerized actin cytoskeleton that lacked actin stress fibers anchored at vinculin-containing focal adhesion sites as well as loss of E-cadherin-mediated cell-cell adherence after exposure to chronic HG, and were concomitant with constitutive ERK1/2 phosphorylation that was refractory to serum and glucose deprivation. Although inhibition of ERK phosphorylation by PD98059 promoted actin polymerization, it increased apoptosis and GSIS impairment. These findings suggest that ERK phosphorylation is a proximate regulator of cellular processes targeted by chronic HG-induced gene expression and that dynamic actin polymerization and depolymerization is important in β cell survival and function. Therefore, chronic HG alters gene expression and signal transduction to predispose the cytoskeleton towards apoptosis and GSIS impairment.
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Affiliation(s)
- Ronne Wee Yeh Yeo
- Institute of Medical Biology, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
- Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore, Singapore
| | | | - GuoDong Li
- Department of Clinical Research, Singapore General Hospital, Singapore, Singapore
| | - Sai Kiang Lim
- Institute of Medical Biology, Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
- Department of Surgery, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- * E-mail:
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Abstract
During evolution, beta cells adapted to a sole aim: the production and stimulus-dependent secretion of insulin. This acquired specificity was accompanied by a loss of protection mechanisms predisposing beta cell to a high vulnerability. Among beta cell-damaging molecules, a new one has been identified recently: macrophage migration inhibitory factor (MIF). MIF was at first designated as a T-cell product that inhibits random movement of macrophages. Over the years, the number of functions attributed to this protein increased significantly, positioning MIF at the top of inflammatory cascade in the combat against infection and in immunoinflammatory and autoimmune diseases. This exceptionally versatile molecule regulates insulin secretion in physiological conditions, while in pathological states it alters beta cell function and induces their apoptosis or necrosis and affects beta cell neoplasia.
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Zhou G, Liu SH, Shahi KM, Wang H, Duan X, Lin X, Feng XH, Li M, Fisher WE, Demayo FJ, Dawson D, Brunicardi FC. Negative regulation of pancreatic and duodenal homeobox-1 by somatostatin receptor subtype 5. Mol Endocrinol 2012; 26:1225-34. [PMID: 22669743 DOI: 10.1210/me.2012-1095] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Somatostatin receptor subtype 5 (SSTR5) mediates the inhibitory effect of somatostatin and its analogs on insulin expression/secretion and islet cell proliferation. We provide biochemical and genetic evidence that SSTR5 exerted its physiological actions via down-regulating pancreatic and duodenal homeobox-1 (PDX-1), a β-cell-specific homeodomain-containing transcription factor. Cotransfection of SSTR5 with PDX-1 resulted in dose-dependent inhibition of PDX-1 expression in human embryonic kidney 293 cells. SSTR5 agonist RPL-1980 inhibited PDX-1 expression and abolished glucagon-like peptide 1-stimulated PDX-1 expression in mouse insulinoma β-TC-6 cells. SSTR5 knockdown by short hairpin RNA led to increased PDX-1 expression that was accompanied by enhanced insulin secretion stimulated by high glucose in β-TC6 cells and alternated expressions of cell cycle proteins that favor cell proliferation in mouse insulinoma MIN6 cells. Quantitative RT-PCR analysis showed that cotransfected SSTR5 inhibited PDX-1 mRNA expression, whereas knockdown of SSTR5 increased PDX-1 mRNA expression. In addition, we found that cotransfected wild-type SSTR5 increased PDX-1 ubiquitination in human embryonic kidney 293 cells, whereas SSTR5 P335L, a hypofunctional single nucleotide polymorphism of SSTR5, inhibited PDX-1 ubiquitination. SSTR5 knockout resulted in increased expression of PDX-1, insulin, and proliferating cell nuclear antigen in the islets of sstr(-/-) mice. Immunohistochemistry analysis showed that SSTR5 P335L was associated with elevated expression of PDX-1 in human pancreatic neuroendocrine tumor. Taken together, our studies demonstrated that SSTR5 is a negative regulator for PDX-1 expression and that SSTR5 may mediate the inhibitory effects of somatostatin and its analogs on insulin expression/secretion and cell proliferation via down-regulating PDX-1 at both transcriptional and posttranslational levels.
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Affiliation(s)
- Guisheng Zhou
- Department of Surgery, David Geffen School of Medicine at University of California, Los Angeles, California 90095, USA
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Endoplasmic reticulum stress and insulin biosynthesis: a review. EXPERIMENTAL DIABETES RESEARCH 2012; 2012:509437. [PMID: 22474424 PMCID: PMC3303544 DOI: 10.1155/2012/509437] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/14/2011] [Accepted: 12/06/2011] [Indexed: 12/21/2022]
Abstract
Insulin resistance and pancreatic beta cell dysfunction are major contributors to the pathogenesis of diabetes. Various conditions play a role in the pathogenesis of pancreatic beta cell dysfunction and are correlated with endoplasmic reticulum (ER) stress. Pancreatic beta cells are susceptible to ER stress. Many studies have shown that increased ER stress induces pancreatic beta cell dysfunction and diabetes mellitus using genetic models of ER stress and by various stimuli. There are many reports indicating that ER stress plays an important role in the impairment of insulin biosynthesis, suggesting that reduction of ER stress could be a therapeutic target for diabetes. In this paper, we reviewed the relationship between ER stress and diabetes and how ER stress controls insulin biosynthesis.
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Abstract
The recent epidemic of type 2 diabetes in Asia differs from that reported in other regions of the world in several key areas: it has evolved over a much shorter time, in an earlier stage of life, and in people with lower body mass indices. These phenotypic characteristics of patients strongly suggest that insulin secretory defects may perform a more important function in the development and progression of diabetes. A genetic element clearly underlies β-cell dysfunction and insufficient β-cell mass; however, a number of modifiable factors are also linked to β-cell deterioration, most notably chronic hyperglycemia and elevated free fatty acid (FFA) levels. Neither glucose nor FFAs alone cause clinically meaningful β-cell toxicity, especially in patients with normal or impaired glucose tolerance. Thus the term "glucolipotoxicity" is perhaps more appropriate in describing the phenomenon. Several mechanisms have been proposed to explain glucolipotoxicity-induced β-cell dysfunction and death, but its major factors appear to be depression of key transcription factor gene expression by altered intracellular energy metabolism and oxidative stress. Therefore, stabilization of metabolic changes induced by glucolipotoxicity in β-cells represents a new avenue for the treatment of type 2 diabetes mellitus.
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Affiliation(s)
- Ji-Won Kim
- Department of Endocrinology and Metabolism, Convergent Research Consortium for Immunologic Disease, The Catholic University of Korea, Seoul, Korea
| | - Kun-Ho Yoon
- Department of Endocrinology and Metabolism, Convergent Research Consortium for Immunologic Disease, The Catholic University of Korea, Seoul, Korea
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Kanat M, Norton L, Winnier D, Jenkinson C, DeFronzo RA, Abdul-Ghani MA. Impaired early- but not late-phase insulin secretion in subjects with impaired fasting glucose. Acta Diabetol 2011; 48:209-17. [PMID: 21553243 DOI: 10.1007/s00592-011-0285-x] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2011] [Accepted: 04/11/2011] [Indexed: 12/21/2022]
Abstract
Subjects with impaired fasting glucose (IFG) are at increased risk for type 2 diabetes. We recently demonstrated that IFG subjects have increased hepatic insulin resistance with normal insulin sensitivity in skeletal muscle. In this study, we quantitated the insulin secretion rate from deconvolution analysis of the plasma C-peptide concentration during an oral glucose tolerance test (OGTT) and compared the results in IFG subjects with those in subjects with impaired glucose tolerance (IGT) and normal glucose tolerance (NGT). One hundred and one NGT subjects, 64 subjects with isolated IGT, 24 subjects with isolated IFG, and 48 subjects with combined (IFG + IGT) glucose intolerance (CGI) received an OGTT. Plasma glucose, insulin, and C-peptide concentrations were measured before and every 15 min after glucose ingestion. Insulin secretion rate (ISR) was determined by deconvolution of plasma C-peptide concentration. Inverse of the Matsuda index of whole body insulin sensitivity was used as a measure of insulin resistance; 56 subjects also received a euglycemic hyperinsulinemic clamp. The insulin secretion/insulin resistance (disposition) index was calculated as the ratio between incremental area under the ISR curve (∆ISR[AUC]) to incremental area under the glucose curve (∆G[AUC]) factored by the severity of insulin resistance (measured by Matsuda index during OGTT or glucose disposal during insulin clamp). Compared to NGT, the insulin secretion/insulin resistance index during first 30 min of OGTT was reduced by 47, 49, and 74% in IFG, IGT, and CGI, respectively (all < 0.0001). The insulin secretion/insulin resistance index during the second hour (60-120 min) of the OGTT in subjects with IFG was similar to that in NGT (0.79 ± 0.6 vs. 0.72 ± 0.5, respectively, P = NS), but was profoundly reduced in subjects with IGT and CGI (0.31 ± 0.2 and 0.19 ± 0.11, respectively; P < 0.0001 vs. both NGT and IFG). Early-phase insulin secretion is impaired in both IFG and IGT, while the late-phase insulin secretion is impaired only in subjects with IGT.
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Affiliation(s)
- Mustafa Kanat
- Diabetes Division, University of Texas Health Science Center, San Antonio, 78229, USA
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48
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Abstract
Increasing evidences have suggested that oxidative stress plays a major role in the pathogenesis of diabetes mellitus (DM). Oxidative stress also appears to be the pathogenic factor in underlying diabetic complications. Reactive oxygen species (ROS) are generated by environmental factors, such as ionizing radiation and chemical carcinogens, and also by endogenous processes, including energy metabolism in mitochondria. ROS produced either endogenously or exogenously can attack lipids, proteins and nucleic acids simultaneously in living cells. There are many potential mechanisms whereby excess glucose metabolites traveling along these pathways might promote the development of DM complication and cause pancreatic β cell damage. However, all these pathways have in common the formation of ROS, that, in excess and over time, causes chronic oxidative stress, which in turn causes defective insulin gene expression and insulin secretion as well as increased apoptosis. Various methods for determining biomarkers of cellular oxidative stress have been developed, and some have been proposed for sensitive assessment of antioxidant defense and oxidative damage in diabetes and its complications. However, their clinical utility is limited by less than optimal standardization techniques and the lack of sufficient large-sized, multi-marker prospective trials.
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Affiliation(s)
- Hui Yang
- Department of Laboratory Medicine, China-Japan Friendship Hospital, Ministry of Health, Beijing, PR China
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Abdul-Ghani MA, Norton L, Defronzo RA. Role of sodium-glucose cotransporter 2 (SGLT 2) inhibitors in the treatment of type 2 diabetes. Endocr Rev 2011; 32:515-31. [PMID: 21606218 DOI: 10.1210/er.2010-0029] [Citation(s) in RCA: 317] [Impact Index Per Article: 24.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Hyperglycemia plays an important role in the pathogenesis of type 2 diabetes mellitus, i.e., glucotoxicity, and it also is the major risk factor for microvascular complications. Thus, effective glycemic control will not only reduce the incidence of microvascular complications but also correct some of the metabolic abnormalities that contribute to the progression of the disease. Achieving durable tight glycemic control is challenging because of progressive β-cell failure and is hampered by increased frequency of side effects, e.g., hypoglycemia and weight gain. Most recently, inhibitors of the renal sodium-glucose cotransporter have been developed to produce glucosuria and reduce the plasma glucose concentration. These oral antidiabetic agents have the potential to improve glycemic control while avoiding hypoglycemia, to correct the glucotoxicity, and to promote weight loss. In this review, we will summarize the available data concerning the mechanism of action, efficacy, and safety of this novel antidiabetic therapeutic approach.
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Guri AJ, Bassaganya-Riera J. Systemic effects of white adipose tissue dysregulation and obesity-related inflammation. Obesity (Silver Spring) 2011; 19:689-700. [PMID: 20930712 DOI: 10.1038/oby.2010.230] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Amir J Guri
- Nutritional Immunology and Molecular Medicine Laboratory, CyberInfrastructure Division, Virginia Bioinformatics Institute, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, USA
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