1
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Zhang Z, Li M, Lin P, Ren Y, He Y, Wang S, Xu Y, Cao B, Wang G, Moran MF, Mao X. The ubiquitin ligase HERC4 suppresses MafA transcriptional activity triggered by GSK3β in myeloma by atypical K63-linked polyubiquitination. J Biol Chem 2023; 299:104675. [PMID: 37028761 DOI: 10.1016/j.jbc.2023.104675] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2022] [Revised: 03/23/2023] [Accepted: 03/29/2023] [Indexed: 04/09/2023] Open
Abstract
MafA and c-Maf are close members of the Maf transcription factor family and indicators of poor prognosis of multiple myeloma (MM). Our previous study finds that the ubiquitin ligase HERC4 induces c-Maf degradation but stabilizes MafA, and the mechanism is elusive. In the present study we find that HERC4 interacts with MafA and mediates its K63-linked polyubiquitination at K33. Moreover, HERC4 inhibits MafA phosphorylation and its transcriptional activity triggered by glycogen synthase kinase 3β (GSK3β). The K33R MafA variant prevents HERC4 from inhibiting MafA phosphorylation and increases MafA transcriptional activity. Further analyses reveal that MafA can also activate the STAT3 signaling but it is suppressed by HERC4. Lastly, we demonstrate that lithium chloride, a GSK3β inhibitor, can upregulate HERC4 and synergizes dexamethasone, a typical anti-MM drug, in inhibiting MM cell proliferation and xenograft growth in nude mice. These findings thus highlight a novel regulation of MafA oncogenic activity in MM and provide the rationale by targeting HERC4/GSK3β/MafA for the treatment of MM.
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Affiliation(s)
- Zubin Zhang
- Jiangsu Key Laboratory for Translational Research and Therapeutics of NeuroPsychoDiseases, Department of Pharmacology, College of Pharmaceutical Sciences, Soochow University, Suzhou, Jiangsu, 215123, China.
| | - Mei Li
- Institute of Pediatric Research, Children's Hospital of Soochow University, Suzhou, Jiangsu, 215025, China
| | - Peng Lin
- Jiangsu Key Laboratory for Translational Research and Therapeutics of NeuroPsychoDiseases, Department of Pharmacology, College of Pharmaceutical Sciences, Soochow University, Suzhou, Jiangsu, 215123, China
| | - Ying Ren
- Jiangsu Key Laboratory for Translational Research and Therapeutics of NeuroPsychoDiseases, Department of Pharmacology, College of Pharmaceutical Sciences, Soochow University, Suzhou, Jiangsu, 215123, China
| | - Yuanming He
- Jiangsu Key Laboratory for Translational Research and Therapeutics of NeuroPsychoDiseases, Department of Pharmacology, College of Pharmaceutical Sciences, Soochow University, Suzhou, Jiangsu, 215123, China
| | - Siyu Wang
- Jiangsu Key Laboratory for Translational Research and Therapeutics of NeuroPsychoDiseases, Department of Pharmacology, College of Pharmaceutical Sciences, Soochow University, Suzhou, Jiangsu, 215123, China
| | - Yujia Xu
- Jiangsu Key Laboratory for Translational Research and Therapeutics of NeuroPsychoDiseases, Department of Pharmacology, College of Pharmaceutical Sciences, Soochow University, Suzhou, Jiangsu, 215123, China
| | - Biyin Cao
- Jiangsu Key Laboratory for Translational Research and Therapeutics of NeuroPsychoDiseases, Department of Pharmacology, College of Pharmaceutical Sciences, Soochow University, Suzhou, Jiangsu, 215123, China
| | - Guanghui Wang
- Jiangsu Key Laboratory for Translational Research and Therapeutics of NeuroPsychoDiseases, Department of Pharmacology, College of Pharmaceutical Sciences, Soochow University, Suzhou, Jiangsu, 215123, China
| | - Michael F Moran
- The Department of Molecular Genetics, The University of Toronto, Toronto, ON, M5G 0A4, Canada
| | - Xinliang Mao
- Jiangsu Key Laboratory for Translational Research and Therapeutics of NeuroPsychoDiseases, Department of Pharmacology, College of Pharmaceutical Sciences, Soochow University, Suzhou, Jiangsu, 215123, China; Guangdong Provincial Key Laboratory of Protein Modification and Degradation, State Key Laboratory of Respiratory Diseases, School of Basic Medical Sciences, Guangzhou Medical University, Guangzhou, Guangdong, 511436, China.
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2
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Sasaki S, Lee MYY, Wakabayashi Y, Suzuki L, Winata H, Himuro M, Matsuoka TA, Shimomura I, Watada H, Lynn FC, Miyatsuka T. Spatial and transcriptional heterogeneity of pancreatic beta cell neogenesis revealed by a time-resolved reporter system. Diabetologia 2022; 65:811-828. [PMID: 35243521 DOI: 10.1007/s00125-022-05662-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Accepted: 12/14/2021] [Indexed: 01/08/2023]
Abstract
AIMS/HYPOTHESIS While pancreatic beta cells have been shown to originate from endocrine progenitors in ductal regions, it remains unclear precisely where beta cells emerge from and which transcripts define newborn beta cells. We therefore investigated characteristics of newborn beta cells extracted by a time-resolved reporter system. METHODS We established a mouse model, 'Ins1-GFP; Timer', which provides spatial information during beta cell neogenesis with high temporal resolution. Single-cell RNA-sequencing (scRNA-seq) was performed on mouse beta cells sorted by fluorescent reporter to uncover transcriptomic profiles of newborn beta cells. scRNA-seq of human embryonic stem cell (hESC)-derived beta-like cells was also performed to compare newborn beta cell features between mouse and human. RESULTS Fluorescence imaging of Ins1-GFP; Timer mouse pancreas successfully dissected newly generated beta cells as green fluorescence-dominant cells. This reporter system revealed that, as expected, some newborn beta cells arise close to the ducts (βduct); unexpectedly, the others arise away from the ducts and adjacent to blood vessels (βvessel). Single-cell transcriptomic analyses demonstrated five distinct populations among newborn beta cells, confirming spatial heterogeneity of beta cell neogenesis such as high probability of glucagon-positive βduct, musculoaponeurotic fibrosarcoma oncogene family B (MafB)-positive βduct and musculoaponeurotic fibrosarcoma oncogene family A (MafA)-positive βvessel cells. Comparative analysis with scRNA-seq data of mouse newborn beta cells and hESC-derived beta-like cells uncovered transcriptional similarity between mouse and human beta cell neogenesis including microsomal glutathione S-transferase 1 (MGST1)- and synaptotagmin 13 (SYT13)-highly-expressing state. CONCLUSIONS/INTERPRETATION The combination of time-resolved histological imaging with single-cell transcriptional mapping demonstrated novel features of spatial and transcriptional heterogeneity in beta cell neogenesis, which will lead to a better understanding of beta cell differentiation for future cell therapy. DATA AVAILABILITY Raw and processed single-cell RNA-sequencing data for this study has been deposited in the Gene Expression Omnibus under accession number GSE155742.
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Affiliation(s)
- Shugo Sasaki
- Department of Metabolic Medicine, Osaka University Graduate School of Medicine, Osaka, Japan.
- Department of Diabetes Care Medicine, Osaka University Graduate School of Medicine, Osaka, Japan.
- Diabetes Research Group, BC Children's Hospital Research Institute, Vancouver, BC, Canada.
- Department of Surgery, School of Biomedical Engineering, University of British Columbia, Vancouver, BC, Canada.
| | - Michelle Y Y Lee
- Diabetes Research Group, BC Children's Hospital Research Institute, Vancouver, BC, Canada
| | - Yuka Wakabayashi
- Department of Metabolism and Endocrinology, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Luka Suzuki
- Department of Metabolism and Endocrinology, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Helena Winata
- Diabetes Research Group, BC Children's Hospital Research Institute, Vancouver, BC, Canada
| | - Miwa Himuro
- Department of Metabolism and Endocrinology, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Taka-Aki Matsuoka
- Department of Metabolic Medicine, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Iichiro Shimomura
- Department of Metabolic Medicine, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Hirotaka Watada
- Department of Metabolism and Endocrinology, Juntendo University Graduate School of Medicine, Tokyo, Japan
- Center for Identification of Diabetic Therapeutic Targets, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Francis C Lynn
- Diabetes Research Group, BC Children's Hospital Research Institute, Vancouver, BC, Canada.
- Department of Surgery, School of Biomedical Engineering, University of British Columbia, Vancouver, BC, Canada.
| | - Takeshi Miyatsuka
- Department of Metabolism and Endocrinology, Juntendo University Graduate School of Medicine, Tokyo, Japan.
- Center for Identification of Diabetic Therapeutic Targets, Juntendo University Graduate School of Medicine, Tokyo, Japan.
- Department of Endocrinology, Diabetes and Metabolism, Kitasato University School of Medicine, Kanagawa, Japan.
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3
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Role of the Transcription Factor MAFA in the Maintenance of Pancreatic β-Cells. Int J Mol Sci 2022; 23:ijms23094478. [PMID: 35562869 PMCID: PMC9101179 DOI: 10.3390/ijms23094478] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 04/16/2022] [Accepted: 04/17/2022] [Indexed: 02/04/2023] Open
Abstract
Pancreatic β-cells are specialized to properly regulate blood glucose. Maintenance of the mature β-cell phenotype is critical for glucose metabolism, and β-cell failure results in diabetes mellitus. Recent studies provide strong evidence that the mature phenotype of β-cells is maintained by several transcription factors. These factors are also required for β-cell differentiation from endocrine precursors or maturation from immature β-cells during pancreatic development. Because the reduction or loss of these factors leads to β-cell failure and diabetes, inducing the upregulation or inhibiting downregulation of these transcription factors would be beneficial for studies in both diabetes and stem cell biology. Here, we discuss one such factor, i.e., the transcription factor MAFA. MAFA is a basic leucine zipper family transcription factor that can activate the expression of insulin in β-cells with PDX1 and NEUROD1. MAFA is indeed indispensable for the maintenance of not only insulin expression but also function of adult β-cells. With loss of MAFA in type 2 diabetes, β-cells cannot maintain their mature phenotype and are dedifferentiated. In this review, we first briefly summarize the functional roles of MAFA in β-cells and then mainly focus on the molecular mechanism of cell fate conversion regulated by MAFA.
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4
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Liang J, Chirikjian M, Pajvani UB, Bartolomé A. MafA Regulation in β-Cells: From Transcriptional to Post-Translational Mechanisms. Biomolecules 2022; 12:biom12040535. [PMID: 35454124 PMCID: PMC9033020 DOI: 10.3390/biom12040535] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 03/29/2022] [Accepted: 03/30/2022] [Indexed: 11/17/2022] Open
Abstract
β-cells are insulin-producing cells in the pancreas that maintain euglycemic conditions. Pancreatic β-cell maturity and function are regulated by a variety of transcription factors that enable the adequate expression of the cellular machinery involved in nutrient sensing and commensurate insulin secretion. One of the key factors in this regulation is MAF bZIP transcription factor A (MafA). MafA expression is decreased in type 2 diabetes, contributing to β-cell dysfunction and disease progression. The molecular biology underlying MafA is complex, with numerous transcriptional and post-translational regulatory nodes. Understanding these complexities may uncover potential therapeutic targets to ameliorate β-cell dysfunction. This article will summarize the role of MafA in normal β-cell function and disease, with a special focus on known transcriptional and post-translational regulators of MafA expression.
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Affiliation(s)
- Jiani Liang
- Department of Medicine, Columbia University, New York, NY 10032, USA; (J.L.); (M.C.); (U.B.P.)
| | - Margot Chirikjian
- Department of Medicine, Columbia University, New York, NY 10032, USA; (J.L.); (M.C.); (U.B.P.)
| | - Utpal B. Pajvani
- Department of Medicine, Columbia University, New York, NY 10032, USA; (J.L.); (M.C.); (U.B.P.)
| | - Alberto Bartolomé
- Instituto de Investigaciones Biomédicas Alberto Sols, CSIC-UAM, 28029 Madrid, Spain
- Correspondence:
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You S, Zheng J, Chen Y, Huang H. Research progress on the mechanism of beta-cell apoptosis in type 2 diabetes mellitus. Front Endocrinol (Lausanne) 2022; 13:976465. [PMID: 36060972 PMCID: PMC9434279 DOI: 10.3389/fendo.2022.976465] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Accepted: 08/01/2022] [Indexed: 11/23/2022] Open
Abstract
Type 2 diabetes mellitus(T2DM) is regarded as one of the most severe chronic metabolic diseases worldwide, which poses a great threat to human safety and health. The main feature of T2DM is the deterioration of pancreatic beta-cell function. More and more studies have shown that the decline of pancreatic beta-cell function in T2DM can be attributable to beta-cell apoptosis, but the exact mechanisms of beta-cell apoptosis in T2DM are not yet fully clarified. Therefore, in this review, we will focus on the current status and progress of research on the mechanism of pancreatic beta-cell apoptosis in T2DM, to provide new ideas for T2DM treatment strategies.
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Affiliation(s)
- SuFang You
- The Second Clinical Medical College of Fujian Medical University, Quanzhou, China
- Department of Endocrinology, The Second Affiliated Hospital of Fujian Medical University, Quanzhou, China
| | - JingYi Zheng
- Department of Endocrinology, The Second Affiliated Hospital of Fujian Medical University, Quanzhou, China
| | - YuPing Chen
- Department of Endocrinology, The Second Affiliated Hospital of Fujian Medical University, Quanzhou, China
| | - HuiBin Huang
- Department of Endocrinology, The Second Affiliated Hospital of Fujian Medical University, Quanzhou, China
- *Correspondence: HuiBin Huang,
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6
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Benáková Š, Holendová B, Plecitá-Hlavatá L. Redox Homeostasis in Pancreatic β-Cells: From Development to Failure. Antioxidants (Basel) 2021; 10:antiox10040526. [PMID: 33801681 PMCID: PMC8065646 DOI: 10.3390/antiox10040526] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Revised: 03/23/2021] [Accepted: 03/25/2021] [Indexed: 12/16/2022] Open
Abstract
Redox status is a key determinant in the fate of β-cell. These cells are not primarily detoxifying and thus do not possess extensive antioxidant defense machinery. However, they show a wide range of redox regulating proteins, such as peroxiredoxins, thioredoxins or thioredoxin reductases, etc., being functionally compartmentalized within the cells. They keep fragile redox homeostasis and serve as messengers and amplifiers of redox signaling. β-cells require proper redox signaling already in cell ontogenesis during the development of mature β-cells from their progenitors. We bring details about redox-regulated signaling pathways and transcription factors being essential for proper differentiation and maturation of functional β-cells and their proliferation and insulin expression/maturation. We briefly highlight the targets of redox signaling in the insulin secretory pathway and focus more on possible targets of extracellular redox signaling through secreted thioredoxin1 and thioredoxin reductase1. Tuned redox homeostasis can switch upon chronic pathological insults towards the dysfunction of β-cells and to glucose intolerance. These are characteristics of type 2 diabetes, which is often linked to chronic nutritional overload being nowadays a pandemic feature of lifestyle. Overcharged β-cell metabolism causes pressure on proteostasis in the endoplasmic reticulum, mainly due to increased demand on insulin synthesis, which establishes unfolded protein response and insulin misfolding along with excessive hydrogen peroxide production. This together with redox dysbalance in cytoplasm and mitochondria due to enhanced nutritional pressure impact β-cell redox homeostasis and establish prooxidative metabolism. This can further affect β-cell communication in pancreatic islets through gap junctions. In parallel, peripheral tissues losing insulin sensitivity and overall impairment of glucose tolerance and gut microbiota establish local proinflammatory signaling and later systemic metainflammation, i.e., low chronic inflammation prooxidative properties, which target β-cells leading to their dedifferentiation, dysfunction and eventually cell death.
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Affiliation(s)
- Štěpánka Benáková
- Department of Mitochondrial Physiology, Institute of Physiology, Czech Academy of Sciences, 142 20 Prague 4, Czech Republic; (Š.B.); (B.H.)
- First Faculty of Medicine, Charles University, Katerinska 1660/32, 121 08 Prague, Czech Republic
| | - Blanka Holendová
- Department of Mitochondrial Physiology, Institute of Physiology, Czech Academy of Sciences, 142 20 Prague 4, Czech Republic; (Š.B.); (B.H.)
| | - Lydie Plecitá-Hlavatá
- Department of Mitochondrial Physiology, Institute of Physiology, Czech Academy of Sciences, 142 20 Prague 4, Czech Republic; (Š.B.); (B.H.)
- Department of Mitochondrial Physiology, Czech Academy of Sciences, Videnska 1083, 142 20 Prague 4, Czech Republic
- Correspondence: ; Tel.: +420-296-442-285
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7
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Blanchet E, Pessemesse L, Feillet-Coudray C, Coudray C, Cabello C, Bertrand-Gaday C, Casas F. p43, a Truncated Form of Thyroid Hormone Receptor α, Regulates Maturation of Pancreatic β Cells. Int J Mol Sci 2021; 22:ijms22052489. [PMID: 33801253 PMCID: PMC7958131 DOI: 10.3390/ijms22052489] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Revised: 02/19/2021] [Accepted: 02/25/2021] [Indexed: 01/18/2023] Open
Abstract
P43 is a truncated form of thyroid hormone receptor α localized in mitochondria, which stimulates mitochondrial respiratory chain activity. Previously, we showed that deletion of p43 led to reduction of pancreatic islet density and a loss of glucose-stimulated insulin secretion in adult mice. The present study was designed to determine whether p43 was involved in the processes of β cell development and maturation. We used neonatal, juvenile, and adult p43-/- mice, and we analyzed the development of β cells in the pancreas. Here, we show that p43 deletion affected only slightly β cell proliferation during the postnatal period. However, we found a dramatic fall in p43-/- mice of MafA expression (V-Maf Avian Musculoaponeurotic Fibrosarcoma Oncogene Homolog A), a key transcription factor of beta-cell maturation. Analysis of the expression of antioxidant enzymes in pancreatic islet and 4-hydroxynonenal (4-HNE) (a specific marker of lipid peroxidation) staining revealed that oxidative stress occurred in mice lacking p43. Lastly, administration of antioxidants cocktail to p43-/- pregnant mice restored a normal islet density but failed to ensure an insulin secretion in response to glucose. Our findings demonstrated that p43 drives the maturation of β cells via its induction of transcription factor MafA during the critical postnatal window.
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8
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Ebrahimi AG, Hollister-Lock J, Sullivan BA, Tsuchida R, Bonner-Weir S, Weir GC. Beta cell identity changes with mild hyperglycemia: Implications for function, growth, and vulnerability. Mol Metab 2020; 35:100959. [PMID: 32244186 PMCID: PMC7082551 DOI: 10.1016/j.molmet.2020.02.002] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 02/03/2020] [Accepted: 02/04/2020] [Indexed: 02/08/2023] Open
Abstract
OBJECTIVE As diabetes develops, marked reductions of insulin secretion are associated with very modest elevations of glucose. We wondered if these glucose changes disrupt beta cell differentiation enough to account for the altered function. METHODS Rats were subjected to 90% partial pancreatectomies and those with only mild glucose elevations 4 weeks or 10 weeks after surgery had major alterations of gene expression in their islets as determined by RNAseq. RESULTS Changes associated with glucose toxicity demonstrated that many of the critical genes responsible for insulin secretion were downregulated while the expression of normally suppressed genes increased. Also, there were marked changes in genes associated with replication, aging, senescence, stress, inflammation, and increased expression of genes controlling both class I and II MHC antigens. CONCLUSIONS These findings suggest that mild glucose elevations in the early stages of diabetes lead to phenotypic changes that adversely affect beta cell function, growth, and vulnerability.
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Affiliation(s)
- Aref G Ebrahimi
- Section on Islet Cell and Regenerative Biology, Joslin Diabetes Center, One Joslin Place, Harvard Medical School, Boston, MA 02215, USA
| | - Jennifer Hollister-Lock
- Section on Islet Cell and Regenerative Biology, Joslin Diabetes Center, One Joslin Place, Harvard Medical School, Boston, MA 02215, USA
| | - Brooke A Sullivan
- Section on Islet Cell and Regenerative Biology, Joslin Diabetes Center, One Joslin Place, Harvard Medical School, Boston, MA 02215, USA
| | - Ryohei Tsuchida
- Section on Islet Cell and Regenerative Biology, Joslin Diabetes Center, One Joslin Place, Harvard Medical School, Boston, MA 02215, USA
| | - Susan Bonner-Weir
- Section on Islet Cell and Regenerative Biology, Joslin Diabetes Center, One Joslin Place, Harvard Medical School, Boston, MA 02215, USA
| | - Gordon C Weir
- Section on Islet Cell and Regenerative Biology, Joslin Diabetes Center, One Joslin Place, Harvard Medical School, Boston, MA 02215, USA.
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9
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Zhang P, Li T, Wu X, Nice EC, Huang C, Zhang Y. Oxidative stress and diabetes: antioxidative strategies. Front Med 2020; 14:583-600. [PMID: 32248333 DOI: 10.1007/s11684-019-0729-1] [Citation(s) in RCA: 194] [Impact Index Per Article: 48.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2019] [Accepted: 10/29/2019] [Indexed: 12/20/2022]
Abstract
Diabetes mellitus is one of the major public health problems worldwide. Considerable recent evidence suggests that the cellular reduction-oxidation (redox) imbalance leads to oxidative stress and subsequent occurrence and development of diabetes and related complications by regulating certain signaling pathways involved in β-cell dysfunction and insulin resistance. Reactive oxide species (ROS) can also directly oxidize certain proteins (defined as redox modification) involved in the diabetes process. There are a number of potential problems in the clinical application of antioxidant therapies including poor solubility, storage instability and nonselectivity of antioxidants. Novel antioxidant delivery systems may overcome pharmacokinetic and stability problem and improve the selectivity of scavenging ROS. We have therefore focused on the role of oxidative stress and antioxidative therapies in the pathogenesis of diabetes mellitus. Precise therapeutic interventions against ROS and downstream targets are now possible and provide important new insights into the treatment of diabetes.
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Affiliation(s)
- Pengju Zhang
- Department of Pharmacology, West China School of Basic Medical Sciences & Forensic Medicine, Sichuan University, Chengdu, 610041, China
| | - Tao Li
- Department of Pharmacology, West China School of Basic Medical Sciences & Forensic Medicine, Sichuan University, Chengdu, 610041, China
| | - Xingyun Wu
- Department of Pharmacology, West China School of Basic Medical Sciences & Forensic Medicine, Sichuan University, Chengdu, 610041, China
| | - Edouard C Nice
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia
| | - Canhua Huang
- Department of Pharmacology, West China School of Basic Medical Sciences & Forensic Medicine, Sichuan University, Chengdu, 610041, China.
| | - Yuanyuan Zhang
- Department of Pharmacology, West China School of Basic Medical Sciences & Forensic Medicine, Sichuan University, Chengdu, 610041, China.
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Chen H, Zhou W, Ruan Y, Yang L, Xu N, Chen R, Yang R, Sun J, Zhang Z. Reversal of angiotensin ll-induced β-cell dedifferentiation via inhibition of NF-κb signaling. Mol Med 2018; 24:43. [PMID: 30134927 PMCID: PMC6092859 DOI: 10.1186/s10020-018-0044-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Accepted: 07/30/2018] [Indexed: 12/11/2022] Open
Abstract
Background Type 2 diabetes mellitus (T2DM) is characterized by pancreatic β-cell failure, which arises from metabolic stress and results in β cell dedifferentiation, leading to β-cell death. Pathological activation of the renin–angiotensin system (RAS) contributes to increase cell stress, while RAS intervention reduces the onset of T2DM in high-risk populations and promotes insulin secretion in rodents. In this study, we investigated whether and how RAS induces β-cell dedifferentiation and the mechanism underlying this process. Methods In vitro, with the methods of quantitative real-time reverse transcriptase-PCR (qRT-PCR) and western blotting, we examined the change of cell identity-related gene expression, progenitor like gene expression, cellular function, and nuclear factor kappa b (NF-κb) signaling activity in β cell lines after exposure to angiotensin II (AngII) and disruption of RAS. In vivo, parallel studies were performed using db/db mice. Related protein expression was detected by Immunofluorescence analysis. Result Activation of RAS induced dedifferentiation and impaired insulin secretion, eventually leading to β-cell failure. Mechanistically, Angll induced β-cell dedifferentiation via NF-κb signaling, while treatment with lrbesartan and sc-514 reversed the progenitor state of β cells. Conclusion The present study found that RAS might induce β-cell dedifferentiation via angiotensin II receptor type 1 activation, which was promoted by NF-κb signaling. Therefore, blocking RAS or NF-kb signaling efficiently reversed the dedifferentiated status of β cells, suggesting a potential therapy for patients with type 2 diabetes. Electronic supplementary material The online version of this article (10.1186/s10020-018-0044-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Hong Chen
- Department of Endocrinology, Zhujiang Hospital, Southern Medical University, 253, Gongyedadao Middle, Guangzhou, Guangdong, 510282, People's Republic of China
| | - Wenjun Zhou
- Department of Endocrinology, Zhujiang Hospital, Southern Medical University, 253, Gongyedadao Middle, Guangzhou, Guangdong, 510282, People's Republic of China
| | - Yuting Ruan
- Department of Endocrinology, Zhujiang Hospital, Southern Medical University, 253, Gongyedadao Middle, Guangzhou, Guangdong, 510282, People's Republic of China
| | - Lei Yang
- Department of Nephrology, Zhujiang Hospital, Southern Medical University, 253, Gongyedadao Middle, Guangzhou, Guangdong, 510282, People's Republic of China
| | - Ningning Xu
- Department of Endocrinology, Zhujiang Hospital, Southern Medical University, 253, Gongyedadao Middle, Guangzhou, Guangdong, 510282, People's Republic of China
| | - Rongping Chen
- Department of Endocrinology, Zhujiang Hospital, Southern Medical University, 253, Gongyedadao Middle, Guangzhou, Guangdong, 510282, People's Republic of China
| | - Rui Yang
- Department of Endocrinology, Zhujiang Hospital, Southern Medical University, 253, Gongyedadao Middle, Guangzhou, Guangdong, 510282, People's Republic of China
| | - Jia Sun
- Department of Endocrinology, Zhujiang Hospital, Southern Medical University, 253, Gongyedadao Middle, Guangzhou, Guangdong, 510282, People's Republic of China.
| | - Zhen Zhang
- Department of Endocrinology, Zhujiang Hospital, Southern Medical University, 253, Gongyedadao Middle, Guangzhou, Guangdong, 510282, People's Republic of China.
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11
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Qiang YW, Ye S, Huang Y, Chen Y, Van Rhee F, Epstein J, Walker BA, Morgan GJ, Davies FE. MAFb protein confers intrinsic resistance to proteasome inhibitors in multiple myeloma. BMC Cancer 2018; 18:724. [PMID: 29980194 PMCID: PMC6035431 DOI: 10.1186/s12885-018-4602-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Accepted: 06/18/2018] [Indexed: 11/29/2022] Open
Abstract
Background Multiple myeloma (MM) patients with t(14;20) have a poor prognosis and their outcome has not improved following the introduction of bortezomib (Bzb). The mechanism underlying the resistance to proteasome inhibitors (PIs) for this subset of patients is unknown. Methods IC50 of Bzb and carfilzomib (CFZ) in human myeloma cell lines (HMCLs) were established by MTT assay. Gene Expression profile (GEP) analysis was used to determine gene expression in primary myeloma cells. Immunoblotting analysis was performed for MAFb and caspase family proteins. Immunofluorescence staining was used to detect the location of MAFb protein in MM cells. Lentiviral infections were used to knock-down MAFb expression in two lines. Apoptosis detection by flow cytometry and western blot analysis was performed to determine the molecular mechanism MAFb confers resistance to proteasome inhibitors. Results We found high levels of MAFb protein in cell lines with t(14;20), in one line with t(6;20), in one with Igλ insertion into MAFb locus, and in primary plasma cells from MM patients with t(14;20). High MAFb protein levels correlated with higher IC50s of PIs in MM cells. Inhibition of GSK3β activity or treatment with Bzb or CFZ prevented MAFb protein degradation without affecting the corresponding mRNA level indicating a role for GSK3 and proteasome inhibitors in regulation of MAFb stability. Silencing MAFb restored sensitivity to Bzb and CFZ, and enhanced PIs-induced apoptosis and activation of caspase-3, − 8, − 9, PARP and lamin A/C suggesting that high expression of MAFb protein leads to insensitivity to proteasome inhibitors. Conclusion These results highlight the role of post-translational modification of MAFb in maintaining its protein level, and identify a mechanism by which proteasome inhibitors induced stabilization of MAFb confers resistance to proteasome inhibitors, and provide a rationale for the development of targeted therapeutic strategies for this subset of patients. Electronic supplementary material The online version of this article (10.1186/s12885-018-4602-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Ya-Wei Qiang
- Myeloma Institute, University of Arkansas for Medical Sciences, Winthrop P. Rockefeller Cancer Institute, 4301 West Markham St., Slot 776, Rm 914, Little Rock, AR, 72205, USA.
| | - Shiqiao Ye
- Myeloma Institute, University of Arkansas for Medical Sciences, Winthrop P. Rockefeller Cancer Institute, 4301 West Markham St., Slot 776, Rm 914, Little Rock, AR, 72205, USA
| | - Yuhua Huang
- Myeloma Institute, University of Arkansas for Medical Sciences, Winthrop P. Rockefeller Cancer Institute, 4301 West Markham St., Slot 776, Rm 914, Little Rock, AR, 72205, USA
| | - Yu Chen
- Myeloma Institute, University of Arkansas for Medical Sciences, Winthrop P. Rockefeller Cancer Institute, 4301 West Markham St., Slot 776, Rm 914, Little Rock, AR, 72205, USA
| | - Frits Van Rhee
- Myeloma Institute, University of Arkansas for Medical Sciences, Winthrop P. Rockefeller Cancer Institute, 4301 West Markham St., Slot 776, Rm 914, Little Rock, AR, 72205, USA
| | - Joshua Epstein
- Myeloma Institute, University of Arkansas for Medical Sciences, Winthrop P. Rockefeller Cancer Institute, 4301 West Markham St., Slot 776, Rm 914, Little Rock, AR, 72205, USA
| | - Brian A Walker
- Myeloma Institute, University of Arkansas for Medical Sciences, Winthrop P. Rockefeller Cancer Institute, 4301 West Markham St., Slot 776, Rm 914, Little Rock, AR, 72205, USA
| | - Gareth J Morgan
- Myeloma Institute, University of Arkansas for Medical Sciences, Winthrop P. Rockefeller Cancer Institute, 4301 West Markham St., Slot 776, Rm 914, Little Rock, AR, 72205, USA
| | - Faith E Davies
- Myeloma Institute, University of Arkansas for Medical Sciences, Winthrop P. Rockefeller Cancer Institute, 4301 West Markham St., Slot 776, Rm 914, Little Rock, AR, 72205, USA
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12
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Petry SF, Sun LM, Knapp A, Reinl S, Linn T. Distinct Shift in Beta-Cell Glutaredoxin 5 Expression Is Mediated by Hypoxia and Lipotoxicity Both In Vivo and In Vitro. Front Endocrinol (Lausanne) 2018; 9:84. [PMID: 29593651 PMCID: PMC5857561 DOI: 10.3389/fendo.2018.00084] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Accepted: 02/22/2018] [Indexed: 01/04/2023] Open
Abstract
Histomorphological and functional alterations in pancreatic islet composition directly correlate with hyperglycemia severity. Progressive deterioration of metabolic control in subjects suffering from type 2 diabetes is predominantly caused by impaired beta-cell functionality. The glutaredoxin system is supposed to wield protective properties for beta-cells. Therefore, we sought to identify a correlation between the structural changes observed in diabetic pancreatic islets with altered glutaredoxin 5 expression, in order to determine an underlying mechanism of beta-cell impairment. Islets of db/db mice presenting with uncontrolled diabetes were assessed in terms of morphological structure and insulin, glucagon, and glutaredoxin 5 expression. MIN6 cell function and glutaredoxin 5 expression were analyzed after exposure to oleic acid and hypoxia. Islets of diabese mice were marked by typical remodeling and distinct reduction of, and shifts, in localization of glutaredoxin 5-positive cells. These islets featured decreased glutaredoxin 5 as well as insulin and glucagon content. In beta-cell culture, glutaredoxin 5 protein and mRNA expression were decreased by hypoxia and oleic acid but not by leptin treatment. Our study demonstrates that glutaredoxin 5 expression patterns are distinctively altered in islets of rodents presenting with uncontrolled diabesity. In vitro, reduction of islet-cell glutaredoxin 5 expression was mediated by hypoxia and oleic acid. Thus, glutaredoxin 5-deficiency in islets during diabetes may be caused by lipotoxicity and hypoxia.
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Affiliation(s)
- Sebastian Friedrich Petry
- Clinical Research Unit, Center of Internal Medicine, Justus Liebig University, Giessen, Germany
- *Correspondence: Sebastian Friedrich Petry,
| | - Lia Mingzhe Sun
- Clinical Research Unit, Center of Internal Medicine, Justus Liebig University, Giessen, Germany
| | - Anna Knapp
- Clinical Research Unit, Center of Internal Medicine, Justus Liebig University, Giessen, Germany
| | - Sabrina Reinl
- Clinical Research Unit, Center of Internal Medicine, Justus Liebig University, Giessen, Germany
| | - Thomas Linn
- Clinical Research Unit, Center of Internal Medicine, Justus Liebig University, Giessen, Germany
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Chandravanshi B, Bhonde RR. Shielding Engineered Islets With Mesenchymal Stem Cells Enhance Survival Under Hypoxia. J Cell Biochem 2017; 118:2672-2683. [PMID: 28098405 DOI: 10.1002/jcb.25885] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Accepted: 01/13/2017] [Indexed: 12/21/2022]
Abstract
In the present study we focused on the improvisation of islet survival in hypoxia.The Islet like cell aggregates (ICAs) derived from wharton's jelly mesenchymal stem cells (WJ MSC) were cultured with and without WJ MSC for 48 h in hypoxia and normoxia and tested for their direct trophic effect on β cell survival. The WJ MSCs themselves secreted insulin upon glucose challenge and expressed the pancreatic markers at both transcription and translational level (C-peptide, Insulin, Glucagon, and Glut 2). Direct contact of MSCs with ICAs facilitated highest viability under hypoxia as evidenced by fluorescein diacetate/propidium iodide and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The cytokine analysis of the co-cultured ICAs revealed amplification of anti-inflammatory cytokine like TGFβ and TNFα accompanied by depletion of pro-inflammatory cytokines. The increment in VEGF and PDGFa was also seen showing their ability to vascularize upon transplantation. This was further accompanied by reduction in total reactive oxygen species, nitric oxide, and super oxide ions and down regulation of Caspase3, Caspase8, p53, and up regulation of Bcl2 confirming prevention of apoptosis in ICAs. The western blot analysis confirmed the cytoprotective effect of WJ MSC on ICAs as they enhanced the anti-apoptotic marker BCL2 and reduced the expression of apoptotic markers, Annexin 5 and Caspase 3. There was a significant reduction in the expression of p38 protein in the presence of MSCs making the ICAs responsive to glucose. Taken together our data demonstrate for the first time that the WJ MSC expressed pancreatic markers and their supplementation protected engineered islets against hypoxia and oxidative stress. J. Cell. Biochem. 118: 2672-2683, 2017. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Bhawna Chandravanshi
- School of Regenerative Medicine, Manipal University, Bangalore, Karnataka, India
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14
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Wang W, Liu C, Jimenez-Gonzalez M, Song WJ, Hussain MA. The undoing and redoing of the diabetic β-cell. J Diabetes Complications 2017; 31:912-917. [PMID: 28242267 PMCID: PMC5450161 DOI: 10.1016/j.jdiacomp.2017.01.028] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Revised: 12/23/2016] [Accepted: 01/31/2017] [Indexed: 02/08/2023]
Abstract
A hallmark of type 2 diabetes (T2DM) is the reduction in functional β-cell mass, which is considered at least in part to result from an imbalance of β-cell renewal and apoptosis, with the latter being accelerated during metabolic stress. More recent studies, however, suggest that the loss of functional β-cell mass is not as much due to β-cell death but rather to de-differentiation of β-cells when these cells are exposed to metabolic stressors, opening the possibility to re-differentiate and restore functional β-cell mass by therapeutic intervention. In parallel, clinical observations suggest that temporary intensive insulin therapy in early diagnosed humans with T2DM, so as to "rest" endogenous β-cells, allows these patients to regain adequate insulin secretion and to maintain euglycemia for prolonged periods free of continued pharmacotherapy. Whether observations made in (mostly rodent) models of diabetes mellitus and in clinical trials are revealing identical mechanisms and therapeutic opportunities remains a tantalizing possibility. Our intention is for this review to serve as an overview of the field and commentary of this particularly exciting field of research.
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Affiliation(s)
- Wei Wang
- Metabolism Division, Departments of Pediatrics, Medicine and Biological Chemistry, Johns Hopkins University School of Medicine, 600 N Wolfe Street, CMSC 10-113, Baltimore, MD 21287
| | - Chune Liu
- Metabolism Division, Departments of Pediatrics, Medicine and Biological Chemistry, Johns Hopkins University School of Medicine, 600 N Wolfe Street, CMSC 10-113, Baltimore, MD 21287
| | - Maria Jimenez-Gonzalez
- Metabolism Division, Departments of Pediatrics, Medicine and Biological Chemistry, Johns Hopkins University School of Medicine, 600 N Wolfe Street, CMSC 10-113, Baltimore, MD 21287
| | - Woo-Jin Song
- Metabolism Division, Departments of Pediatrics, Medicine and Biological Chemistry, Johns Hopkins University School of Medicine, 600 N Wolfe Street, CMSC 10-113, Baltimore, MD 21287
| | - Mehboob A Hussain
- Metabolism Division, Departments of Pediatrics, Medicine and Biological Chemistry, Johns Hopkins University School of Medicine, 600 N Wolfe Street, CMSC 10-113, Baltimore, MD 21287.
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15
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Gerber PA, Rutter GA. The Role of Oxidative Stress and Hypoxia in Pancreatic Beta-Cell Dysfunction in Diabetes Mellitus. Antioxid Redox Signal 2017; 26:501-518. [PMID: 27225690 PMCID: PMC5372767 DOI: 10.1089/ars.2016.6755] [Citation(s) in RCA: 375] [Impact Index Per Article: 53.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Accepted: 05/25/2016] [Indexed: 12/16/2022]
Abstract
SIGNIFICANCE Metabolic syndrome is a frequent precursor of type 2 diabetes mellitus (T2D), a disease that currently affects ∼8% of the adult population worldwide. Pancreatic beta-cell dysfunction and loss are central to the disease process, although understanding of the underlying molecular mechanisms is still fragmentary. Recent Advances: Oversupply of nutrients, including glucose and fatty acids, and the subsequent overstimulation of beta cells, are believed to be an important contributor to insulin secretory failure in T2D. Hypoxia has also recently been implicated in beta-cell damage. Accumulating evidence points to a role for oxidative stress in both processes. Although the production of reactive oxygen species (ROS) results from enhanced mitochondrial respiration during stimulation with glucose and other fuels, the expression of antioxidant defense genes is unusually low (or disallowed) in beta cells. CRITICAL ISSUES Not all subjects with metabolic syndrome and hyperglycemia go on to develop full-blown diabetes, implying an important role in disease risk for gene-environment interactions. Possession of common risk alleles at the SLC30A8 locus, encoding the beta-cell granule zinc transporter ZnT8, may affect cytosolic Zn2+ concentrations and thus susceptibility to hypoxia and oxidative stress. FUTURE DIRECTIONS Loss of normal beta-cell function, rather than total mass, is increasingly considered to be the major driver for impaired insulin secretion in diabetes. Better understanding of the role of oxidative changes, its modulation by genes involved in disease risk, and effects on beta-cell identity may facilitate the development of new therapeutic strategies to this disease. Antioxid. Redox Signal. 26, 501-518.
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Affiliation(s)
- Philipp A. Gerber
- Department of Endocrinology, Diabetes and Clinical Nutrition, University Hospital Zurich, Zurich, Switzerland
| | - Guy A. Rutter
- Section of Cell Biology and Functional Genomics, Department of Medicine, Imperial College London, London, United Kingdom
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16
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AKINCI E, YILDIZ M, ÜNAL P, BADAKUL G. In vitro transcription and validation of human pancreatic transcription factors’ mRNAs. Turk J Biol 2017. [DOI: 10.3906/biy-1610-29] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
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17
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El Khattabi I, Sharma A. Proper activation of MafA is required for optimal differentiation and maturation of pancreatic β-cells. Best Pract Res Clin Endocrinol Metab 2015; 29:821-31. [PMID: 26696512 PMCID: PMC4690007 DOI: 10.1016/j.beem.2015.09.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
A key therapeutic approach for the treatment of Type 1 diabetes (T1D) is transplantation of functional islet β-cells. Despite recent advances in generating stem cell-derived glucose-responsive insulin(+) cells, their further maturation to fully functional adult β-cells still remains a daunting task. Conquering this hurdle will require a better understanding of the mechanisms driving maturation of embryonic insulin(+) cells into adult β-cells, and the implementation of that knowledge to improve current differentiation protocols. Here, we will review our current understanding of β-cell maturation, and discuss the contribution of key β-cell transcription factor MafA, to this process. The fundamental importance of MafA in regulating adult β-cell maturation and function indicates that enhancing MafA expression may improve the generation of definitive β-cells for transplantation. Additionally, we suggest that the temporal control of MafA induction at a specific stage of β-cell differentiation will be the next critical challenge for achieving optimum maturation of β-cells.
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Affiliation(s)
| | - Arun Sharma
- Cardiovascular and Metabolic Diseases, MedImmune, Gaithersburg, MD 20878, USA.
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18
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Aldosterone induces clonal β-cell failure through glucocorticoid receptor. Sci Rep 2015; 5:13215. [PMID: 26287126 PMCID: PMC4541150 DOI: 10.1038/srep13215] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Accepted: 07/20/2015] [Indexed: 12/21/2022] Open
Abstract
Aldosterone excess causes insulin resistance in peripheral tissues and directly impairs the function of clonal β-cell. The aim of this study was to investigate the molecular mechanisms involved in the aldosterone-induced impairment of clonal β-cells. As expected, aldosterone induced apoptosis and β-cell dysfunction, including impairment of insulin synthesis and secretion, which were reversed by Glucocorticoid receptor (GR) antagonists or GR-specific siRNA. However, mineralocorticoid receptor (MR) antagonists or MR-specific siRNA had no effect on impairment of clonal β-cells induced by aldosterone. Besides, aldosterone significantly decreased expression and activity of MafA, while activated JNK and p38 MAPK in a GR-dependent manner. In addition, JNK inhibitors (SP600125) and/or p38 inhibitors (SB203580) could abolish the effect of aldosterone on MafA expression and activity. Importantly, overexpression of JNK1 or p38 reversed the protective effect of a GR antagonist on the decrease of MafA expression and activity. Furthermore, aldosterone inhibits MafA expression at the transcriptional and post-transcriptional level through activation of JNK and p38, respectively. Consequently, overexpression of MafA increased synthesis and secretion of insulin, and decreased apoptosis in clonal β-cells exposed to aldosterone. These findings identified aldosterone as an inducer of clonal β-cell failure that operates through the GR-MAPK-MafA signaling pathway.
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19
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Kang L, Dai C, Lustig ME, Bonner JS, Mayes WH, Mokshagundam S, James FD, Thompson CS, Lin CT, Perry CGR, Anderson EJ, Neufer PD, Wasserman DH, Powers AC. Heterozygous SOD2 deletion impairs glucose-stimulated insulin secretion, but not insulin action, in high-fat-fed mice. Diabetes 2014; 63:3699-710. [PMID: 24947366 PMCID: PMC4207395 DOI: 10.2337/db13-1845] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Elevated reactive oxygen species (ROS) are linked to insulin resistance and islet dysfunction. Manganese superoxide dismutase (SOD2) is a primary defense against mitochondrial oxidative stress. To test the hypothesis that heterozygous SOD2 deletion impairs glucose-stimulated insulin secretion (GSIS) and insulin action, wild-type (sod2(+/+)) and heterozygous knockout mice (sod2(+/-)) were fed a chow or high-fat (HF) diet, which accelerates ROS production. Hyperglycemic (HG) and hyperinsulinemic-euglycemic (HI) clamps were performed to assess GSIS and insulin action in vivo. GSIS during HG clamps was equal in chow-fed sod2(+/-) and sod2(+/+) but was markedly decreased in HF-fed sod2(+/-). Remarkably, this impairment was not paralleled by reduced HG glucose infusion rate (GIR). Decreased GSIS in HF-fed sod2(+/-) was associated with increased ROS, such as superoxide ion. Surprisingly, insulin action determined by HI clamps did not differ between sod2(+/-) and sod2(+/+) of either diet. Since insulin action was unaffected, we hypothesized that the unchanged HG GIR in HF-fed sod2(+/-) was due to increased glucose effectiveness. Increased GLUT-1, hexokinase II, and phospho-AMPK protein in muscle of HF-fed sod2(+/-) support this hypothesis. We conclude that heterozygous SOD2 deletion in mice, a model that mimics SOD2 changes observed in diabetic humans, impairs GSIS in HF-fed mice without affecting insulin action.
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Affiliation(s)
- Li Kang
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN Mouse Metabolic Phenotyping Center, Vanderbilt University, Nashville, TN Division of Cardiovascular and Diabetes Medicine, Ninewells Hospital and Medical School, University of Dundee, Dundee, U.K.
| | - Chunhua Dai
- Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, Vanderbilt University, Nashville, TN
| | - Mary E Lustig
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN
| | - Jeffrey S Bonner
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN
| | - Wesley H Mayes
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN
| | - Shilpa Mokshagundam
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN
| | - Freyja D James
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN
| | - Courtney S Thompson
- Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, Vanderbilt University, Nashville, TN
| | - Chien-Te Lin
- East Carolina Diabetes and Obesity Institute and Departments of Physiology and Kinesiology, East Carolina University, Greenville, NC
| | - Christopher G R Perry
- East Carolina Diabetes and Obesity Institute and Departments of Physiology and Kinesiology, East Carolina University, Greenville, NC
| | - Ethan J Anderson
- East Carolina Diabetes and Obesity Institute and Departments of Physiology and Kinesiology, East Carolina University, Greenville, NC
| | - P Darrell Neufer
- East Carolina Diabetes and Obesity Institute and Departments of Physiology and Kinesiology, East Carolina University, Greenville, NC
| | - David H Wasserman
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN Mouse Metabolic Phenotyping Center, Vanderbilt University, Nashville, TN
| | - Alvin C Powers
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, Vanderbilt University, Nashville, TN Veterans Affairs Tennessee Valley Healthcare System, Nashville, TN
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Li Y, Xiao J, Tian H, Pei Y, Lu Y, Han X, Liu Y, Zhong W, Sun B, Fang F, Shu H. The DPP-4 inhibitor MK0626 and exercise protect islet function in early pre-diabetic kkay mice. Peptides 2013; 49:91-9. [PMID: 24025600 DOI: 10.1016/j.peptides.2013.08.021] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Revised: 08/30/2013] [Accepted: 08/30/2013] [Indexed: 12/11/2022]
Abstract
Dipeptidyl peptidase-4 (DPP-4) inhibitor and exercise have proven to be effective treatments for diabetes. However, the effects of these interventions in compensatory hyperinsulinemia prediabetic period are unknown. The purpose of this study was to determine if these interventions have protective effects on β-cell function and preventive effects on the onset of diabetes in prediabetic kkay mice. After 2 weeks of high-fat diet feeding, we treated 7-week-old mice with a normal diet, high-fat diet, exercise training, or the DPP-4 inhibitor for 8 weeks. C57BL/6J mice served as a normal control. Kkay mice without intervention developed diabetes at week 15, but no diabetic mice were observed in the DPP-4I or exercise groups as well as the normal control group. The DPP-4I and exercise groups showed improved body weight, blood glucose level, glucose tolerance, insulin sensitivity, islet area, and islet morphology. In addition, the proportion of Ki67-positive β-cells in the treatment groups was obviously higher than that in the untreated groups. MafA (V-maf musculoaponeurotic fibrosarcoma oncogene homolog A) expression in the treated groups increased markedly. However PDX-1 (pancreatic and duodenal homeobox-1) expression did not differ significantly among the groups. The results show that exercise and DPP-4I treatment conducted during the hyperinsulinemic prediabetic stage contribute to the maintenance of β-cell function and morphology, enhance β-cell proliferation, extend the compensatory insulin hypersecretion period, and delay disease onset. The expression of PDX-1 was not altered significantly during the early stages of diabetes. However, the reduced expression of the insulin transcription factor MafA may play an important role in the development of prediabetes.
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Affiliation(s)
- Yupeng Li
- Tianjin Medical University, Metabolic Diseases Hospital & Tianjin Endocrinology Institute, No. 66, TongAn Road, Heping District, Tianjin, China
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He KH, Juhl K, Karadimos M, El Khattabi I, Fitzpatrick C, Bonner-Weir S, Sharma A. Differentiation of pancreatic endocrine progenitors reversibly blocked by premature induction of MafA. Dev Biol 2013; 385:2-12. [PMID: 24183936 DOI: 10.1016/j.ydbio.2013.10.024] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Revised: 10/22/2013] [Accepted: 10/23/2013] [Indexed: 12/12/2022]
Abstract
Specification and maturation of insulin(+) cells accompanies a transition in expression of Maf family of transcription factors. In development, MafA is expressed after specification of insulin(+) cells that are expressing another Maf factor, MafB; after birth, these insulin(+) MafA(+) cells stop MafB expression and gain glucose responsiveness. Current differentiation protocols for deriving insulin-producing β-cells from stem cells result in β-cells lacking both MafA expression and glucose-stimulated insulin secretion. So driving expression of MafA, a β-cell maturation factor in endocrine precursors could potentially generate glucose-responsive MafA(+) β cells. Using inducible transgenic mice, we characterized the final stages of β-cell differentiation and maturation with MafA pause/release experiments. We found that forcing MafA transgene expression, out of its normal developmental context, in Ngn3(+) endocrine progenitors blocked endocrine differentiation and prevented the formation of hormone(+) cells. However, this arrest was reversible such that with stopping the transgene expression, the cells resumed their differentiation to hormone(+) cells, including α-cells, indicating that the block likely occurred after progenitors had committed to a specific hormonal fate. Interestingly, this delayed resumption of endocrine differentiation resulted in a greater proportion of immature insulin(+)MafB(+) cells at P5, demonstrating that during maturation the inhibition of MafB in β-cell transitioning from insulin(+)MafB(+) to insulin(+)MafB(-) stage is regulated by cell-autonomous mechanisms. These results demonstrate the importance of proper context of initiating MafA expression on the endocrine differentiation and suggest that generating mature Insulin(+)MafA(+) β-cells will require the induction of MafA in a narrow temporal window to achieve normal endocrine differentiation.
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Affiliation(s)
- KaiHui Hu He
- Section of Islet Cell and Regenerative Biology, Joslin Diabetes Center, Harvard Medical School, One Joslin Place, Boston, MA 02215, United States
| | - Kirstine Juhl
- Section of Islet Cell and Regenerative Biology, Joslin Diabetes Center, Harvard Medical School, One Joslin Place, Boston, MA 02215, United States
| | - Michael Karadimos
- Section of Islet Cell and Regenerative Biology, Joslin Diabetes Center, Harvard Medical School, One Joslin Place, Boston, MA 02215, United States
| | - Ilham El Khattabi
- Section of Islet Cell and Regenerative Biology, Joslin Diabetes Center, Harvard Medical School, One Joslin Place, Boston, MA 02215, United States
| | - Connor Fitzpatrick
- Section of Islet Cell and Regenerative Biology, Joslin Diabetes Center, Harvard Medical School, One Joslin Place, Boston, MA 02215, United States
| | - Susan Bonner-Weir
- Section of Islet Cell and Regenerative Biology, Joslin Diabetes Center, Harvard Medical School, One Joslin Place, Boston, MA 02215, United States
| | - Arun Sharma
- Section of Islet Cell and Regenerative Biology, Joslin Diabetes Center, Harvard Medical School, One Joslin Place, Boston, MA 02215, United States
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Bertrand C, Blanchet E, Pessemesse L, Annicotte JS, Feillet-Coudray C, Chabi B, Levin J, Fajas L, Cabello G, Wrutniak-Cabello C, Casas F. Mice lacking the p43 mitochondrial T3 receptor become glucose intolerant and insulin resistant during aging. PLoS One 2013; 8:e75111. [PMID: 24098680 PMCID: PMC3787095 DOI: 10.1371/journal.pone.0075111] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Accepted: 08/09/2013] [Indexed: 01/29/2023] Open
Abstract
Thyroid hormones (TH) play an important regulatory role in energy expenditure regulation and are key regulators of mitochondrial activity. We have previously identified a mitochondrial triiodothyronine (T3) receptor (p43) which acts as a mitochondrial transcription factor of the organelle genome, which leads in vitro and in vivo, to a stimulation of mitochondrial biogenesis. Recently, we generated mice carrying a specific p43 invalidation. At 2 months of age, we reported that p43 depletion in mice induced a major defect in insulin secretion both in vivo and in isolated pancreatic islets, and a loss of glucose-stimulated insulin secretion. The present study was designed to determine whether p43 invalidation influences life expectancy and modulates blood glucose and insulin levels as well as glucose tolerance or insulin sensitivity during aging. We report that from 4 months old onwards, mice lacking p43 are leaner than wild-type mice. p43−/− mice also have a moderate reduction of life expectancy compared to wild type. We found no difference in blood glucose levels, excepted at 24 months old where p43−/− mice showed a strong hyperglycemia in fasting conditions compared to controls animals. However, the loss of glucose-stimulated insulin secretion was maintained whatever the age of mice lacking p43. If up to 12 months old, glucose tolerance remained unchanged, beyond this age p43−/− mice became increasingly glucose intolerant. In addition, if up to 12 months old p43 deficient animals were more sensitive to insulin, after this age we observed a loss of this capacity, culminating in 24 months old mice with a decreased sensitivity to the hormone. In conclusion, we demonstrated that during aging the depletion of the mitochondrial T3 receptor p43 in mice progressively induced an increased glycemia in the fasted state, glucose intolerance and an insulin-resistance several features of type-2 diabetes.
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Affiliation(s)
- Christelle Bertrand
- INRA, Institut National de la Recherche Agronomique, UMR866 Dynamique Musculaire et Métabolisme, Montpellier, France; Université Montpellier 1, Montpellier, France; Université Montpellier 2, Montpellier, France
| | - Emilie Blanchet
- IGMM, Institut de Génétique Moléculaire de Montpellier, CNRS-UMR5535, Montpellier France; Université Montpellier 1, Montpellier, France; Université Montpellier 2, Montpellier France
| | - Laurence Pessemesse
- INRA, Institut National de la Recherche Agronomique, UMR866 Dynamique Musculaire et Métabolisme, Montpellier, France; Université Montpellier 1, Montpellier, France; Université Montpellier 2, Montpellier, France
| | - Jean Sébastien Annicotte
- IGMM, Institut de Génétique Moléculaire de Montpellier, CNRS-UMR5535, Montpellier France; Université Montpellier 1, Montpellier, France; Université Montpellier 2, Montpellier France
| | - Christine Feillet-Coudray
- INRA, Institut National de la Recherche Agronomique, UMR866 Dynamique Musculaire et Métabolisme, Montpellier, France; Université Montpellier 1, Montpellier, France; Université Montpellier 2, Montpellier, France
| | - Béatrice Chabi
- INRA, Institut National de la Recherche Agronomique, UMR866 Dynamique Musculaire et Métabolisme, Montpellier, France; Université Montpellier 1, Montpellier, France; Université Montpellier 2, Montpellier, France
| | - Jonathan Levin
- INRA, Institut National de la Recherche Agronomique, UMR866 Dynamique Musculaire et Métabolisme, Montpellier, France; Université Montpellier 1, Montpellier, France; Université Montpellier 2, Montpellier, France
| | - Lluis Fajas
- IGMM, Institut de Génétique Moléculaire de Montpellier, CNRS-UMR5535, Montpellier France; Université Montpellier 1, Montpellier, France; Université Montpellier 2, Montpellier France
| | - Gérard Cabello
- INRA, Institut National de la Recherche Agronomique, UMR866 Dynamique Musculaire et Métabolisme, Montpellier, France; Université Montpellier 1, Montpellier, France; Université Montpellier 2, Montpellier, France
| | - Chantal Wrutniak-Cabello
- INRA, Institut National de la Recherche Agronomique, UMR866 Dynamique Musculaire et Métabolisme, Montpellier, France; Université Montpellier 1, Montpellier, France; Université Montpellier 2, Montpellier, France
| | - François Casas
- INRA, Institut National de la Recherche Agronomique, UMR866 Dynamique Musculaire et Métabolisme, Montpellier, France; Université Montpellier 1, Montpellier, France; Université Montpellier 2, Montpellier, France
- * E-mail:
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Abstract
This commentary discusses the concept of β-cell dedifferentiation in diabetes, which is important but not well defined. A broad interpretation is that a state of differentiation has been lost, which means changes in gene expression as well as in structural and functional elements. Thus, a fully mature healthy β cell will have its unique differentiation characteristics, but maturing cells and old β cells will have different patterns of gene expression and might therefore be considered as dedifferentiated. The meaning of dedifferentiation is now being debated because β cells in the diabetic state lose components of their differentiated state, which results in severe dysfunction of insulin secretion. The major cause of this change is thought to be glucose toxicity (glucotoxicity) and that lowering glucose levels with treatment results in some restoration of function. An issue to be discussed is whether dedifferentiated β cells return to a multipotent precursor cell phenotype or whether they follow a different pathway of dedifferentiation.
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El Khattabi I, Sharma A. Preventing p38 MAPK-mediated MafA degradation ameliorates β-cell dysfunction under oxidative stress. Mol Endocrinol 2013; 27:1078-90. [PMID: 23660596 PMCID: PMC3706838 DOI: 10.1210/me.2012-1346] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2012] [Accepted: 04/30/2013] [Indexed: 12/19/2022] Open
Abstract
The reduction in the expression of glucose-responsive insulin gene transcription factor MafA accompanies the development of β-cell dysfunction under oxidative stress/diabetic milieu. Humans with type 2 diabetes have reduced MafA expression, and thus preventing this reduction could overcome β-cell dysfunction and diabetes. We previously showed that p38 MAPK, but not glycogen synthase kinase 3 (GSK3), is a major regulator of MafA degradation under oxidative stress. Here, we examined the mechanisms of this degradation and whether preventing MafA degradation under oxidative stress will overcome β-cell dysfunction. We show that under oxidative and nonoxidative conditions p38 MAPK directly binds to MafA and triggers MafA degradation via ubiquitin proteasomal pathway. However, unlike nonoxidative conditions, MafA degradation under oxidative stress depended on p38 MAPK-mediated phosphorylation at threonine (T) 134, and not T57. Furthermore the expression of alanine (A) 134-MafA, but not A57-MafA, reduced the oxidative stress-mediated loss of glucose-stimulated insulin secretion, which was independent of p38 MAPK action on protein kinase D, a regulator of insulin secretion. Interestingly, the expression of proteasomal activator PA28γ that degrades GSK3-phosphorylated (including T57) MafA was reduced under oxidative stress, explaining the dominance of p38 MAPK over the GSK3 pathway in regulating MafA stability under oxidative stress. These results identify two distinct pathways mediating p38 MAPK-dependent MafA degradation under oxidative and nonoxidative conditions and show that inhibiting MafA degradation under oxidative stress ameliorates β-cell dysfunction and could lead to novel therapies for diabetes.
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Affiliation(s)
- Ilham El Khattabi
- Section of Islet Cell and Regenerative Biology, Joslin Diabetes Center, Harvard Medical School, Boston, Massachusetts 02215, USA
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25
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Guo S, Dai C, Guo M, Taylor B, Harmon JS, Sander M, Robertson RP, Powers AC, Stein R. Inactivation of specific β cell transcription factors in type 2 diabetes. J Clin Invest 2013; 123:3305-16. [PMID: 23863625 DOI: 10.1172/jci65390] [Citation(s) in RCA: 374] [Impact Index Per Article: 34.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2013] [Accepted: 05/01/2013] [Indexed: 01/03/2023] Open
Abstract
Type 2 diabetes (T2DM) commonly arises from islet β cell failure and insulin resistance. Here, we examined the sensitivity of key islet-enriched transcription factors to oxidative stress, a condition associated with β cell dysfunction in both type 1 diabetes (T1DM) and T2DM. Hydrogen peroxide treatment of β cell lines induced cytoplasmic translocation of MAFA and NKX6.1. In parallel, the ability of nuclear PDX1 to bind endogenous target gene promoters was also dramatically reduced, whereas the activity of other key β cell transcriptional regulators was unaffected. MAFA levels were reduced, followed by a reduction in NKX6.1 upon development of hyperglycemia in db/db mice, a T2DM model. Transgenic expression of the glutathione peroxidase-1 antioxidant enzyme (GPX1) in db/db islet β cells restored nuclear MAFA, nuclear NKX6.1, and β cell function in vivo. Notably, the selective decrease in MAFA, NKX6.1, and PDX1 expression was found in human T2DM islets. MAFB, a MAFA-related transcription factor expressed in human β cells, was also severely compromised. We propose that MAFA, MAFB, NKX6.1, and PDX1 activity provides a gauge of islet β cell function, with loss of MAFA (and/or MAFB) representing an early indicator of β cell inactivity and the subsequent deficit of more impactful NKX6.1 (and/or PDX1) resulting in overt dysfunction associated with T2DM.
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26
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Aguayo-Mazzucato C, Zavacki AM, Marinelarena A, Hollister-Lock J, El Khattabi I, Marsili A, Weir GC, Sharma A, Larsen PR, Bonner-Weir S. Thyroid hormone promotes postnatal rat pancreatic β-cell development and glucose-responsive insulin secretion through MAFA. Diabetes 2013; 62:1569-80. [PMID: 23305647 PMCID: PMC3636623 DOI: 10.2337/db12-0849] [Citation(s) in RCA: 102] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Neonatal β cells do not secrete glucose-responsive insulin and are considered immature. We previously showed the transcription factor MAFA is key for the functional maturation of β cells, but the physiological regulators of this process are unknown. Here we show that postnatal rat β cells express thyroid hormone (TH) receptor isoforms and deiodinases in an age-dependent pattern as glucose responsiveness develops. In vivo neonatal triiodothyronine supplementation and TH inhibition, respectively, accelerated and delayed metabolic development. In vitro exposure of immature islets to triiodothyronine enhanced the expression of Mafa, the secretion of glucose-responsive insulin, and the proportion of responsive cells, all of which are effects that were abolished in the presence of dominant-negative Mafa. Using chromatin immunoprecipitation and electrophoretic mobility shift assay, we show that TH has a direct receptor-ligand interaction with the Mafa promoter and, using a luciferase reporter, that this interaction was functional. Thus, TH can be considered a physiological regulator of functional maturation of β cells via its induction of Mafa.
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Affiliation(s)
- Cristina Aguayo-Mazzucato
- Section of Islet Cell and Regenerative Biology, Joslin Diabetes Center, Harvard Medical School, Boston, Massachusetts
| | - Ann Marie Zavacki
- Thyroid Section, Division of Endocrinology, Diabetes and Hypertension, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts
| | - Alejandra Marinelarena
- Section of Islet Cell and Regenerative Biology, Joslin Diabetes Center, Harvard Medical School, Boston, Massachusetts
| | - Jennifer Hollister-Lock
- Section of Islet Cell and Regenerative Biology, Joslin Diabetes Center, Harvard Medical School, Boston, Massachusetts
| | - Ilham El Khattabi
- Section of Islet Cell and Regenerative Biology, Joslin Diabetes Center, Harvard Medical School, Boston, Massachusetts
| | - Alessandro Marsili
- Thyroid Section, Division of Endocrinology, Diabetes and Hypertension, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts
| | - Gordon C. Weir
- Section of Islet Cell and Regenerative Biology, Joslin Diabetes Center, Harvard Medical School, Boston, Massachusetts
| | - Arun Sharma
- Section of Islet Cell and Regenerative Biology, Joslin Diabetes Center, Harvard Medical School, Boston, Massachusetts
| | - P. Reed Larsen
- Thyroid Section, Division of Endocrinology, Diabetes and Hypertension, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts
| | - Susan Bonner-Weir
- Section of Islet Cell and Regenerative Biology, Joslin Diabetes Center, Harvard Medical School, Boston, Massachusetts
- Corresponding author: Susan Bonner-Weir,
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27
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Weir GC, Bonner-Weir S. Islet β cell mass in diabetes and how it relates to function, birth, and death. Ann N Y Acad Sci 2013; 1281:92-105. [PMID: 23363033 PMCID: PMC3618572 DOI: 10.1111/nyas.12031] [Citation(s) in RCA: 229] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
In type 1 diabetes (T1D) β cell mass is markedly reduced by autoimmunity. Type 2 diabetes (T2D) results from inadequate β cell mass and function that can no longer compensate for insulin resistance. The reduction of β cell mass in T2D may result from increased cell death and/or inadequate birth through replication and neogenesis. Reduction in mass allows glucose levels to rise, which places β cells in an unfamiliar hyperglycemic environment, leading to marked changes in their phenotype and a dramatic loss of glucose-stimulated insulin secretion (GSIS), which worsens as glucose levels climb. Toxic effects of glucose on β cells (glucotoxicity) appear to be the culprit. This dysfunctional insulin secretion can be reversed when glucose levels are lowered by treatment, a finding with therapeutic significance. Restoration of β cell mass in both types of diabetes could be accomplished by either β cell regeneration or transplantation. Learning more about the relationships between β cell mass, turnover, and function and finding ways to restore β cell mass are among the most urgent priorities for diabetes research.
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Affiliation(s)
- Gordon C Weir
- Section on Islet Cell Biology and Regenerative Medicine, Research Division, Joslin Diabetes Center, Department of Medicine, Harvard Medical School, Boston, MA 02215, USA.
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28
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Yang SH, Sharrocks AD, Whitmarsh AJ. MAP kinase signalling cascades and transcriptional regulation. Gene 2012; 513:1-13. [PMID: 23123731 DOI: 10.1016/j.gene.2012.10.033] [Citation(s) in RCA: 307] [Impact Index Per Article: 25.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2012] [Revised: 10/08/2012] [Accepted: 10/18/2012] [Indexed: 02/06/2023]
Abstract
The MAP kinase (MAPK) signalling pathways play fundamental roles in a wide range of cellular processes and are often deregulated in disease states. One major mode of action for these pathways is in controlling gene expression, in particular through regulating transcription. In this review, we discuss recent significant advances in this area. In particular we focus on the mechanisms by which MAPKs are targeted to the nucleus and chromatin, and once there, how they impact on chromatin structure and subsequent gene regulation. We also discuss how systems biology approaches have contributed to our understanding of MAPK signaling networks, and also how the MAPK pathways intersect with other regulatory pathways in the nucleus. Finally, we summarise progress in studying the physiological functions of key MAPK transcriptional targets.
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Affiliation(s)
- Shen-Hsi Yang
- Faculty of Life Sciences, University of Manchester, Michael Smith Building, Oxford Road, Manchester, M13 9PT, UK
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29
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Burke SJ, Goff MR, Updegraff BL, Lu D, Brown PL, Minkin SC, Biggerstaff JP, Zhao L, Karlstad MD, Collier JJ. Regulation of the CCL2 gene in pancreatic β-cells by IL-1β and glucocorticoids: role of MKP-1. PLoS One 2012; 7:e46986. [PMID: 23056550 PMCID: PMC3467264 DOI: 10.1371/journal.pone.0046986] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2012] [Accepted: 09/07/2012] [Indexed: 02/06/2023] Open
Abstract
Release of pro-inflammatory cytokines from both resident and invading leukocytes within the pancreatic islets impacts the development of Type 1 diabetes mellitus. Synthesis and secretion of the chemokine CCL2 from pancreatic β-cells in response to pro-inflammatory signaling pathways influences immune cell recruitment into the pancreatic islets. Therefore, we investigated the positive and negative regulatory components controlling expression of the CCL2 gene using isolated rat islets and INS-1-derived β-cell lines. We discovered that activation of the CCL2 gene by IL-1β required the p65 subunit of NF-κB and was dependent on genomic response elements located in the -3.6 kb region of the proximal gene promoter. CCL2 gene transcription in response to IL-1β was blocked by pharmacological inhibition of the IKKβ and p38 MAPK pathways. The IL-1β-mediated increase in CCL2 secretion was also impaired by p38 MAPK inhibition and by glucocorticoids. Moreover, multiple synthetic glucocorticoids inhibited the IL-1β-stimulated induction of the CCL2 gene. Induction of the MAP Kinase Phosphatase-1 (MKP-1) gene by glucocorticoids or by adenoviral-mediated overexpression decreased p38 MAPK phosphorylation, which diminished CCL2 gene expression, promoter activity, and release of CCL2 protein. We conclude that glucocorticoid-mediated repression of IL-1β-induced CCL2 gene transcription and protein secretion occurs in part through the upregulation of the MKP-1 gene and subsequent deactivation of the p38 MAPK. Furthermore, the anti-inflammatory actions observed with MKP-1 overexpression were obtained without suppressing glucose-stimulated insulin secretion. Thus, MKP-1 is a possible target for anti-inflammatory therapeutic intervention with preservation of β-cell function.
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Affiliation(s)
- Susan J. Burke
- Department of Nutrition, University of Tennessee, Knoxville, Tennessee, United States of America
| | - Matthew R. Goff
- Department of Nutrition, University of Tennessee, Knoxville, Tennessee, United States of America
| | - Barrett L. Updegraff
- Department of Nutrition, University of Tennessee, Knoxville, Tennessee, United States of America
| | - Danhong Lu
- Sarah W. Stedman Nutrition and Metabolism Center, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Patricia L. Brown
- Advanced Microscopy and Imaging Center, University of Tennessee, Knoxville, Tennessee, United States of America
| | - Steven C. Minkin
- Advanced Microscopy and Imaging Center, University of Tennessee, Knoxville, Tennessee, United States of America
| | - John P. Biggerstaff
- Advanced Microscopy and Imaging Center, University of Tennessee, Knoxville, Tennessee, United States of America
| | - Ling Zhao
- Department of Nutrition, University of Tennessee, Knoxville, Tennessee, United States of America
- University of Tennessee Obesity Research Center, Knoxville, Tennessee, United States of America
| | - Michael D. Karlstad
- Department of Nutrition, University of Tennessee, Knoxville, Tennessee, United States of America
- Department of Surgery, Graduate School of Medicine, University of Tennessee Medical Center, Knoxville, Tennessee, United States of America
- University of Tennessee Obesity Research Center, Knoxville, Tennessee, United States of America
| | - J. Jason Collier
- Department of Nutrition, University of Tennessee, Knoxville, Tennessee, United States of America
- University of Tennessee Obesity Research Center, Knoxville, Tennessee, United States of America
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30
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Hang Y, Stein R. MafA and MafB activity in pancreatic β cells. Trends Endocrinol Metab 2011; 22:364-73. [PMID: 21719305 PMCID: PMC3189696 DOI: 10.1016/j.tem.2011.05.003] [Citation(s) in RCA: 155] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2011] [Revised: 05/03/2011] [Accepted: 05/18/2011] [Indexed: 12/11/2022]
Abstract
Analyses in mouse models have revealed crucial roles for MafA (musculoaponeurotic fibrosarcoma oncogene family A) and MafB in islet β cells, with MafB being required during development and MafA in adults. These two closely related transcription factors regulate many genes essential for glucose sensing and insulin secretion in a cooperative and sequential manner. Significantly, the switch from MafB to MafA expression also appears to be vital for functional maturation of β cells produced by human embryonic stem (hES) cell differentiation. This review summarizes the discovery, distribution, and function of MafA and MafB in rodent pancreatic β cells, and describes some key questions regarding their importance to β cells.
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Affiliation(s)
| | - Roland Stein
- Correspondence: 723 Light Hall, 2215 Garland Ave Nashville, TN 37232 Phone: 615-322-7026 Facsimile: 615-322-7236
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31
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Aguayo-Mazzucato C, Koh A, El Khattabi I, Li WC, Toschi E, Jermendy A, Juhl K, Mao K, Weir GC, Sharma A, Bonner-Weir S. Mafa expression enhances glucose-responsive insulin secretion in neonatal rat beta cells. Diabetologia 2011; 54:583-93. [PMID: 21190012 PMCID: PMC3047400 DOI: 10.1007/s00125-010-2026-z] [Citation(s) in RCA: 122] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2010] [Accepted: 11/25/2010] [Indexed: 12/21/2022]
Abstract
AIM/HYPOTHESIS Neonatal beta cells lack glucose-stimulated insulin secretion and are thus functionally immature. We hypothesised that this lack of glucose responsiveness results from a generalised low expression of genes characteristic of mature functional beta cells. Important glucose-responsive transcription factors, Mafa and Pdx1, regulate genes involved in insulin synthesis and secretion, and have been implicated in late beta cell development. The aim of this study was to assess whether Mafa and/or Pdx1 regulates the postnatal functional maturation of beta cells. METHODS By quantitative PCR we evaluated expression of these and other beta cell genes over the first month compared with adult. After infection with adenovirus expressing MAFA, Pdx1 or green fluorescent protein (Gfp), P2 rat islets were evaluated by RT-PCR and insulin secretion with static incubation and reverse haemolytic plaque assay (RHPA). RESULTS At P2 most beta cell genes were expressed at about 10% of adult, but by P7 Pdx1 and Neurod1 no longer differ from adult; by contrast, Mafa expression remained significantly lower than adult through P21. Overexpression of Pdx1 increased Mafa, Neurod1, glucokinase (Gck) mRNA and insulin content but failed to enhance glucose responsiveness. Similar overexpression of MAFA resulted in increased Neurod1, Nkx6-1, Gck and Glp1r mRNAs and no change in insulin content but, importantly, acquisition of glucose-responsive insulin secretion. Both the percentage of secreting beta cells and the amount of insulin secreted per beta cell increased, approaching that of adult beta cells. CONCLUSIONS/INTERPRETATION In the process of functional maturation acquiring glucose-responsive insulin secretion, neonatal beta cells undergo a coordinated gene expression programme in which Mafa plays a crucial role.
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32
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Vanderford NL. Comment on: Matsuoka et al. (2010) Regulation of MafA expression in pancreatic beta-cells in db/db mice with diabetes. Diabetes;59:1709-1720. Diabetes 2010; 59:e23. [PMID: 20805381 DOI: 10.2337/db10-0684] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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33
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Tanahashi H, Kito K, Ito T, Yoshioka K. MafB protein stability is regulated by the JNK and ubiquitin-proteasome pathways. Arch Biochem Biophys 2009; 494:94-100. [PMID: 19932079 DOI: 10.1016/j.abb.2009.11.018] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2009] [Revised: 11/14/2009] [Accepted: 11/16/2009] [Indexed: 11/19/2022]
Abstract
MafB is a basic leucine zipper transcription factor that plays important roles in development and differentiation processes. During osteoclastogenesis, its expression is downregulated at the transcriptional level via the JNK and p38 MAP kinase pathways. In the present study, we demonstrated that MafB protein stability is regulated by JNK and identified a phosphorylation site, Thr62. The expression of a constitutively active form of JNK (a fusion protein MKK7alpha1-JNK1beta1) promoted the degradation of MafB in COS7 cells, and a T62A substitution significantly reduced the instability of MafB. The introduction of a fourfold (T58A/T62A/S70A/S74A) substitution in an acidic transcription-activating domain almost protected the instability resulting from the activation of JNK. Furthermore, treatment with proteasome inhibitors increased the MafB level, and a high-molecular-weight smear, characteristic of polyubiquitination, was observed in lysates from cells in which MafB, ubiquitin, and MKK7alpha1-JNK1beta1 were co-expressed. These results suggest that phosphorylation of MafB by JNK confers susceptibility to proteasomal degradation.
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Affiliation(s)
- Hiroshi Tanahashi
- Department of Neuroplasticity, Research Institute on Aging and Adaptation, Shinshu University Graduate School of Medicine, 3-1-1 Asahi, Matsumoto, Japan.
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34
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Weir GC, Marselli L, Marchetti P, Katsuta H, Jung MH, Bonner-Weir S. Towards better understanding of the contributions of overwork and glucotoxicity to the beta-cell inadequacy of type 2 diabetes. Diabetes Obes Metab 2009; 11 Suppl 4:82-90. [PMID: 19817791 DOI: 10.1111/j.1463-1326.2009.01113.x] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Type 2 diabetes (T2D) is characterized by reduction of beta-cell mass and dysfunctional insulin secretion. Understanding beta-cell phenotype changes as T2D progresses should help explain these abnormalities. The normal phenotype should differ from the state of overwork when beta-cells compensate for insulin resistance to keep glucose levels normal. When only mild hyperglycaemia develops, beta-cells are subjected to glucotoxicity. As hyperglycaemia becomes more severe, so does glucotoxicity. beta-Cells in all four of these situations should have separate phenotypes. When assessing phenotype with gene expression, isolated islets have artefacts resulting from the trauma of isolation and hypoxia of islet cores. An advantage comes from laser capture microdissection (LCM), which obtains beta-cell-rich tissue from pancreatic frozen sections. Valuable data can be obtained from animal models, but the real goal is human beta-cells. Our experience with LCM and gene arrays on frozen pancreatic sections from cadaver donors with T2D and controls is described. Although valuable data was obtained, we predict that the approach of taking fresh samples at the time of surgery is an even greater opportunity to markedly advance our understanding of how beta-cell phenotype evolves as T2D develops and progresses.
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Affiliation(s)
- G C Weir
- Joslin Diabetes Center, Harvard Medical School, Boston, MA, USA.
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