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Remedi MS, Nichols CG. Glucokinase Inhibition: A Novel Treatment for Diabetes? Diabetes 2023; 72:170-174. [PMID: 36669001 PMCID: PMC9871191 DOI: 10.2337/db22-0731] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Accepted: 11/12/2022] [Indexed: 01/21/2023]
Abstract
Chronic hyperglycemia increases pancreatic β-cell metabolic activity, contributing to glucotoxicity-induced β-cell failure and loss of functional β-cell mass, potentially in multiple forms of diabetes. In this perspective we discuss the novel paradoxical and counterintuitive concept of inhibiting glycolysis, particularly by targeted inhibition of glucokinase, the first enzyme in glycolysis, as an approach to maintaining glucose sensing and preserving functional β-cell mass, thereby improving insulin secretion, in the treatment of diabetes.
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Affiliation(s)
- Maria S. Remedi
- Division of Endocrinology, Metabolism, and Lipid Research, Department of Medicine, Washington University School of Medicine, St. Louis, MO
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO
- Center for the Investigation of Membrane Excitability Diseases, Washington University School of Medicine, St. Louis, MO
| | - Colin G. Nichols
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO
- Center for the Investigation of Membrane Excitability Diseases, Washington University School of Medicine, St. Louis, MO
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2
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Ashcroft FM, Lloyd M, Haythorne EA. Glucokinase activity in diabetes: too much of a good thing? Trends Endocrinol Metab 2023; 34:119-130. [PMID: 36586779 DOI: 10.1016/j.tem.2022.12.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Accepted: 12/15/2022] [Indexed: 12/31/2022]
Abstract
Type 2 diabetes (T2D) is a global health problem characterised by chronic hyperglycaemia due to inadequate insulin secretion. Because glucose must be metabolised to stimulate insulin release it was initially argued that drugs that stimulate glucokinase (the first enzyme in glucose metabolism) would enhance insulin secretion in diabetes. However, in the long term, glucokinase activators have been largely disappointing. Recent studies show it is hyperactivation of glucose metabolism, not glucose itself, that underlies the progressive decline in beta-cell function in diabetes. This perspective discusses if glucokinase activators exacerbate this decline (by promoting glucose metabolism) and, counterintuitively, if glucokinase inhibitors might be a better therapeutic strategy for preserving beta-cell function in T2D.
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Affiliation(s)
- Frances M Ashcroft
- Department of Physiology, Anatomy and Genetics, Parks Road, Oxford, OX1 3PT, UK.
| | - Matthew Lloyd
- Department of Physiology, Anatomy and Genetics, Parks Road, Oxford, OX1 3PT, UK
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3
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Watanabe H, Du W, Son J, Sui L, Asahara SI, Kurland IJ, Kuo T, Kitamoto T, Miyachi Y, de Cabo R, Accili D. Cyb5r3-based mechanism and reversal of secondary failure to sulfonylurea in diabetes. Sci Transl Med 2023; 15:eabq4126. [PMID: 36724243 DOI: 10.1126/scitranslmed.abq4126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Sulfonylureas (SUs) are effective and affordable antidiabetic drugs. However, chronic use leads to secondary failure, limiting their utilization. Here, we identify cytochrome b5 reductase 3 (Cyb5r3) down-regulation as a mechanism of secondary SU failure and successfully reverse it. Chronic exposure to SU lowered Cyb5r3 abundance and reduced islet glucose utilization in mice in vivo and in ex vivo murine islets. Cyb5r3 β cell-specific knockout mice phenocopied SU failure. Cyb5r3 engaged in a glucose-dependent interaction that stabilizes glucokinase (Gck) to maintain glucose utilization. Hence, Gck activators can circumvent Cyb5r3-dependent SU failure. A Cyb5r3 activator rescued secondary SU failure in mice in vivo and restored insulin secretion in ex vivo human islets. We conclude that Cyb5r3 is a key factor in the secondary failure to SU and a potential target for its prevention, which might rehabilitate SU use in diabetes.
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Affiliation(s)
- Hitoshi Watanabe
- Department of Medicine, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA.,Naomi Berrie Diabetes Center, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - Wen Du
- Department of Medicine, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA.,Naomi Berrie Diabetes Center, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - Jinsook Son
- Department of Medicine, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA.,Naomi Berrie Diabetes Center, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - Lina Sui
- Naomi Berrie Diabetes Center, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA.,Department of Pediatrics, College of Physicians and Surgeons, Columbia University Medical Center, New York, NY 10032, USA
| | - Shun-Ichiro Asahara
- Department of Medicine, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA.,Naomi Berrie Diabetes Center, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA.,Division of Diabetes and Endocrinology, Department of Internal Medicine, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan
| | - Irwin J Kurland
- Stable Isotope and Metabolomics Core Facility, Fleischer Institute for Diabetes and Metabolism, Department of Medicine, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Taiyi Kuo
- Department of Medicine, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA.,Naomi Berrie Diabetes Center, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - Takumi Kitamoto
- Department of Medicine, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA.,Naomi Berrie Diabetes Center, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - Yasutaka Miyachi
- Department of Medicine, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA.,Naomi Berrie Diabetes Center, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | - Rafael de Cabo
- Translational Gerontology Branch, National Institute on Aging, National Institutes of Health, Baltimore, MD 20814, USA
| | - Domenico Accili
- Department of Medicine, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA.,Naomi Berrie Diabetes Center, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
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4
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Llanos P, Ordenes P, Rhoads DB, Santibanez JF, García-Robles M, Millán C. BMAL1 Regulates Glucokinase Expression Through E-Box Elements In Vitro. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1408:235-249. [PMID: 37093431 DOI: 10.1007/978-3-031-26163-3_13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/25/2023]
Abstract
The organization of a circadian system includes an endogenous pacemaker system, input pathways for environmental synchronizing (entraining) stimuli, and output pathways through which the clock regulates physiological and behavioral processes, for example, the glucose-sensing mechanism in the liver. The liver is the central regulator of metabolism and one of our peripherals clocks. In mammals, central to this pacemaker are the transcription factors Circadian Locomotor Output Cycles Kaput (CLOCK) and BMAL1 (Brain and Muscle ARNT-Like 1). BMAL1 dimerizes with CLOCK, and this heterodimer then binds to the E-box promoter elements (CACGTG) present in clock and clock-controlled genes (CCGs). However, we are just beginning to understand how output pathways and regulatory mechanisms of CCGs are involved in rhythmic physiological processes. Glucokinase (GCK) is a fundamental enzyme in glucose homeostasis, catalyzing the high Km phosphorylation of glucose and allowing its storage. Moreover, gck is a dependent circadian gene. This study aims to determine the contribution of clock genes to hepatic gck expression and to define the specific role of E-box sequences on the circadian regulation of hepatic gck. Results showed that gck expression follows a circadian rhythm in rat hepatocytes in vitro. Accordingly, bmal1 expression induces the glucokinase circadian rhythmic expression in hepatocytes and the analysis of human and rat gck promoters, indicating the presence of E-box regions. Moreover, the basal activity of gck promoter was increased by clock/bmal1 co-transfection but inhibited by Period1/Period2 (per1/per2) co-transfection. Thus, the data suggest that the clock proteins tightly regulate the transcriptional activity of the gck promoter.
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Affiliation(s)
- Paula Llanos
- Facultad de Ingeniería y Ciencias, Universidad Adolfo Ibáñez, Viña del Mar, Chile
| | - Patricio Ordenes
- Departmento de Biología Celular, Universidad de Concepción, Concepción, Chile
| | - David B Rhoads
- Harvard Medical School, Boston, MA, US
- Pediatric Endocrinology, Mass General Hospital for Children, Boston, MA, US
| | - Juan F Santibanez
- Institute for Medical Research, National Institute of the Republic of Serbia, University of Belgrade, Belgrade, Serbia
- Integrative Center for Biology and Applied Chemistry (CIBQA), Bernardo O'Higgins University, Santiago, Chile
| | - María García-Robles
- Departmento de Biología Celular, Universidad de Concepción, Concepción, Chile
- Centro Interdisciplinario de Neurociencias de Valparaíso, Instituto de Neurociencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Carola Millán
- Departamento de Ciencias, Facultad de Artes Liberales, Universidad Adolfo Ibáñez, Viña del Mar, Chile.
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5
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Yan Z, Fortunato M, Shyr ZA, Clark AL, Fuess M, Nichols CG, Remedi MS. Genetic Reduction of Glucose Metabolism Preserves Functional β-Cell Mass in KATP-Induced Neonatal Diabetes. Diabetes 2022; 71:1233-1245. [PMID: 35294000 PMCID: PMC9163553 DOI: 10.2337/db21-0992] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Accepted: 03/09/2022] [Indexed: 11/13/2022]
Abstract
β-Cell failure and loss of β-cell mass are key events in diabetes progression. Although insulin hypersecretion in early stages has been implicated in β-cell exhaustion/failure, loss of β-cell mass still occurs in KATP gain-of-function (GOF) mouse models of human neonatal diabetes in the absence of insulin secretion. Thus, we hypothesize that hyperglycemia-induced increased β-cell metabolism is responsible for β-cell failure and that reducing glucose metabolism will prevent loss of β-cell mass. To test this, KATP-GOF mice were crossed with mice carrying β-cell-specific glucokinase haploinsufficiency (GCK+/-), to genetically reduce glucose metabolism. As expected, both KATP-GOF and KATP-GOF/GCK+/- mice showed lack of glucose-stimulated insulin secretion. However, KATP-GOF/GCK+/- mice demonstrated markedly reduced blood glucose, delayed diabetes progression, and improved glucose tolerance compared with KATP-GOF mice. In addition, decreased plasma insulin and content, increased proinsulin, and augmented plasma glucagon observed in KATP-GOF mice were normalized to control levels in KATP-GOF/GCK+/- mice. Strikingly, KATP-GOF/GCK+/- mice demonstrated preserved β-cell mass and identity compared with the marked decrease in β-cell identity and increased dedifferentiation observed in KATP-GOF mice. Moreover KATP-GOF/GCK+/- mice demonstrated restoration of body weight and liver and brown/white adipose tissue mass and function and normalization of physical activity and metabolic efficiency compared with KATP-GOF mice. These results demonstrate that decreasing β-cell glucose signaling can prevent glucotoxicity-induced loss of insulin content and β-cell failure independently of compensatory insulin hypersecretion and β-cell exhaustion.
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Affiliation(s)
- Zihan Yan
- Division of Endocrinology, Metabolism and Lipid Research, Department of Medicine, Washington University School of Medicine, St. Louis, MO
| | - Manuela Fortunato
- Division of Endocrinology, Metabolism and Lipid Research, Department of Medicine, Washington University School of Medicine, St. Louis, MO
| | - Zeenat A. Shyr
- Division of Endocrinology, Metabolism and Lipid Research, Department of Medicine, Washington University School of Medicine, St. Louis, MO
| | - Amy L. Clark
- Department of Pediatrics, Washington University School of Medicine, St. Louis, MO
| | - Matt Fuess
- Division of Endocrinology, Metabolism and Lipid Research, Department of Medicine, Washington University School of Medicine, St. Louis, MO
| | - Colin G. Nichols
- Deparment of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO
- Center for the Investigation of Membrane Excitability Diseases, Washington University School of Medicine, St. Louis, MO
| | - Maria S. Remedi
- Division of Endocrinology, Metabolism and Lipid Research, Department of Medicine, Washington University School of Medicine, St. Louis, MO
- Deparment of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO
- Center for the Investigation of Membrane Excitability Diseases, Washington University School of Medicine, St. Louis, MO
- Corresponding author: Maria S. Remedi,
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6
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Nakamura A. Glucokinase as a therapeutic target based on findings from the analysis of mouse models. Endocr J 2022; 69:479-485. [PMID: 35418527 DOI: 10.1507/endocrj.ej21-0742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
I investigated mouse models to elucidate the pathophysiology and to establish a new treatment strategy for type 2 diabetes, with a particular focus on glucokinase. The decrease in pancreatic beta-cell function and mass are important factors in the pathophysiology of type 2 diabetes. My group have shown that glucokinase plays an important role in high-fat diet-induced and high-starch diet-induced beta-cell expansion. The findings indicated that the mechanism of short-term high-fat diet-induced beta-cell proliferation involved a glucokinase-independent pathway, suggesting that there are different pathways and mechanisms in the proliferation of pancreatic beta-cells during short-term versus long-term high-fat diets. Because enhancement of glucose signals via glucokinase is important for beta-cell proliferation, it was thought that beta-cell mass would be increased and insulin secretion would be maintained by glucokinase activators. However, sub-chronic administration of a glucokinase activator in db/db mice produced an unsustained hypoglycemic effect and promoted hepatic fat accumulation without changes in beta-cell function and mass. In contrast, my group have shown that inactivating glucokinase in beta-cells prevented beta-cell failure and led to an improvement in glucose tolerance in db/db mice. Regulation of glucokinase activity has an influence on the pathophysiology of type 2 diabetes and can be one of the therapeutic targets.
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Affiliation(s)
- Akinobu Nakamura
- Department of Rheumatology, Endocrinology and Nephrology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan
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7
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Chen B, Du YR, Zhu H, Sun ML, Wang C, Cheng Y, Pang H, Ding G, Gao J, Tan Y, Tong X, Lv P, Zhou F, Zhan Q, Xu ZM, Wang L, Luo D, Ye Y, Jin L, Zhang S, Zhu Y, Lin X, Wu Y, Jin L, Zhou Y, Yan C, Sheng J, Flatt PR, Xu GL, Huang H. Maternal inheritance of glucose intolerance via oocyte TET3 insufficiency. Nature 2022; 605:761-766. [PMID: 35585240 DOI: 10.1038/s41586-022-04756-4] [Citation(s) in RCA: 36] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 04/12/2022] [Indexed: 02/05/2023]
Abstract
Diabetes mellitus is prevalent among women of reproductive age, and many women are left undiagnosed or untreated1. Gestational diabetes has profound and enduring effects on the long-term health of the offspring2,3. However, the link between pregestational diabetes and disease risk into adulthood in the next generation has not been sufficiently investigated. Here we show that pregestational hyperglycaemia renders the offspring more vulnerable to glucose intolerance. The expression of TET3 dioxygenase, responsible for 5-methylcytosine oxidation and DNA demethylation in the zygote4, is reduced in oocytes from a mouse model of hyperglycaemia (HG mice) and humans with diabetes. Insufficient demethylation by oocyte TET3 contributes to hypermethylation at the paternal alleles of several insulin secretion genes, including the glucokinase gene (Gck), that persists from zygote to adult, promoting impaired glucose homeostasis largely owing to the defect in glucose-stimulated insulin secretion. Consistent with these findings, mouse progenies derived from the oocytes of maternal heterozygous and homozygous Tet3 deletion display glucose intolerance and epigenetic abnormalities similar to those from the oocytes of HG mice. Moreover, the expression of exogenous Tet3 mRNA in oocytes from HG mice ameliorates the maternal effect in offspring. Thus, our observations suggest an environment-sensitive window in oocyte development that confers predisposition to glucose intolerance in the next generation through TET3 insufficiency rather than through a direct perturbation of the oocyte epigenome. This finding suggests a potential benefit of pre-conception interventions in mothers to protect the health of offspring.
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Affiliation(s)
- Bin Chen
- Key Laboratory of Reproductive Genetics (Ministry of Education), Department of Reproductive Endocrinology, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Assisted Reproduction Unit, Department of Obstetrics and Gynecology, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Key Laboratory of Reproductive Dysfunction Management of Zhejiang Province, Hangzhou, China.,State Key Laboratory of Molecular Biology, Shanghai Key Laboratory of Molecular Andrology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, China
| | - Ya-Rui Du
- State Key Laboratory of Molecular Biology, Shanghai Key Laboratory of Molecular Andrology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, China
| | - Hong Zhu
- Obstetrics and Gynecology Hospital, Institute of Reproduction and Development, Fudan University, Shanghai, China.,Research Units of Embryo Original Diseases, Chinese Academy of Medical Sciences, Shanghai, China
| | - Mei-Ling Sun
- State Key Laboratory of Molecular Biology, Shanghai Key Laboratory of Molecular Andrology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Chao Wang
- State Key Laboratory of Molecular Biology, Shanghai Key Laboratory of Molecular Andrology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Yi Cheng
- Obstetrics and Gynecology Hospital, Institute of Reproduction and Development, Fudan University, Shanghai, China.,Research Units of Embryo Original Diseases, Chinese Academy of Medical Sciences, Shanghai, China
| | - Haiyan Pang
- Key Laboratory of Reproductive Genetics (Ministry of Education), Department of Reproductive Endocrinology, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Guolian Ding
- Obstetrics and Gynecology Hospital, Institute of Reproduction and Development, Fudan University, Shanghai, China.,Research Units of Embryo Original Diseases, Chinese Academy of Medical Sciences, Shanghai, China
| | - Juan Gao
- State Key Laboratory of Molecular Biology, Shanghai Key Laboratory of Molecular Andrology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, China
| | - Yajing Tan
- Shanghai Key Laboratory of Embryo Original Diseases, International Peace Maternity and Child Health Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Xiaomei Tong
- Assisted Reproduction Unit, Department of Obstetrics and Gynecology, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Key Laboratory of Reproductive Dysfunction Management of Zhejiang Province, Hangzhou, China
| | - Pingping Lv
- Key Laboratory of Reproductive Genetics (Ministry of Education), Department of Reproductive Endocrinology, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Feng Zhou
- Assisted Reproduction Unit, Department of Obstetrics and Gynecology, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Key Laboratory of Reproductive Dysfunction Management of Zhejiang Province, Hangzhou, China
| | - Qitao Zhan
- Key Laboratory of Reproductive Genetics (Ministry of Education), Department of Reproductive Endocrinology, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Zhi-Mei Xu
- State Key Laboratory of Molecular Biology, Shanghai Key Laboratory of Molecular Andrology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, China
| | - Li Wang
- Shanghai Key Laboratory of Embryo Original Diseases, International Peace Maternity and Child Health Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Donghao Luo
- Assisted Reproduction Unit, Department of Obstetrics and Gynecology, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Key Laboratory of Reproductive Dysfunction Management of Zhejiang Province, Hangzhou, China
| | - Yinghui Ye
- Key Laboratory of Reproductive Genetics (Ministry of Education), Department of Reproductive Endocrinology, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Li Jin
- Obstetrics and Gynecology Hospital, Institute of Reproduction and Development, Fudan University, Shanghai, China.,Research Units of Embryo Original Diseases, Chinese Academy of Medical Sciences, Shanghai, China
| | - Songying Zhang
- Assisted Reproduction Unit, Department of Obstetrics and Gynecology, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Key Laboratory of Reproductive Dysfunction Management of Zhejiang Province, Hangzhou, China
| | - Yimin Zhu
- Key Laboratory of Reproductive Genetics (Ministry of Education), Department of Reproductive Endocrinology, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Xiaona Lin
- Assisted Reproduction Unit, Department of Obstetrics and Gynecology, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Key Laboratory of Reproductive Dysfunction Management of Zhejiang Province, Hangzhou, China
| | - Yanting Wu
- Obstetrics and Gynecology Hospital, Institute of Reproduction and Development, Fudan University, Shanghai, China.,Research Units of Embryo Original Diseases, Chinese Academy of Medical Sciences, Shanghai, China
| | - Luyang Jin
- Key Laboratory of Reproductive Genetics (Ministry of Education), Department of Reproductive Endocrinology, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Yin Zhou
- Center for Reproductive Medicine, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Caochong Yan
- Key Laboratory of Reproductive Genetics (Ministry of Education), Department of Reproductive Endocrinology, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Jianzhong Sheng
- Key Laboratory of Reproductive Genetics (Ministry of Education), Department of Reproductive Endocrinology, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Peter R Flatt
- Centre for Diabetes Research, School of Biomedical Sciences, Ulster University, Coleraine, UK
| | - Guo-Liang Xu
- State Key Laboratory of Molecular Biology, Shanghai Key Laboratory of Molecular Andrology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, China. .,Shanghai Key Laboratory of Medical Epigenetics, Laboratory of Cancer Epigenetics, Institutes of Biomedical Sciences, Medical College of Fudan University, Chinese Academy of Medical Sciences (RU069), Shanghai, China.
| | - Hefeng Huang
- Key Laboratory of Reproductive Genetics (Ministry of Education), Department of Reproductive Endocrinology, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, China. .,Obstetrics and Gynecology Hospital, Institute of Reproduction and Development, Fudan University, Shanghai, China. .,Research Units of Embryo Original Diseases, Chinese Academy of Medical Sciences, Shanghai, China. .,Shanghai Key Laboratory of Embryo Original Diseases, International Peace Maternity and Child Health Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai, China.
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8
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Ren Y, Li L, Wan L, Huang Y, Cao S. Glucokinase as an emerging anti-diabetes target and recent progress in the development of its agonists. J Enzyme Inhib Med Chem 2022; 37:606-615. [PMID: 35067153 PMCID: PMC8788356 DOI: 10.1080/14756366.2021.2025362] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Type 2 diabetes mellitus is a metabolic disorder with complicated pathogenesis, and mono-target therapy often fails to effectively manage the levels of blood glucose. In recent years, the anti-diabetes target glucokinase (GK) has attracted the attention of researchers. It acts as a glucose sensor, triggering counter regulatory responses following a change in glucose levels to aid restoration of normoglycemia. Activation of GK induces glucose metabolism and reduces glucose levels for the treatment of type 2 diabetes. GK agonists (GKA) are a new class of antidiabetic drugs. Among these agents, dorzagliatin is currently being investigated in phase III clinical trials, while PB-201 and AZD-1656 have reached phase II clinical trials. This article describes the mechanism of action of GK in diabetes and of action of GKA at the protein level, and provides a review of the research, trends, and prospects regarding the use of GKA in this setting.
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Affiliation(s)
- Yixin Ren
- Key Laboratory of Green Chemical Engineering Process of Ministry of Education, School of Chemical Engineering and Pharmacy, Wuhan Institute of Technology, Wuhan, P. R. China
| | - Li Li
- Key Laboratory of Green Chemical Engineering Process of Ministry of Education, School of Chemical Engineering and Pharmacy, Wuhan Institute of Technology, Wuhan, P. R. China
| | - Li Wan
- Key Laboratory of Green Chemical Engineering Process of Ministry of Education, School of Chemical Engineering and Pharmacy, Wuhan Institute of Technology, Wuhan, P. R. China
| | - Yan Huang
- Key Laboratory of Green Chemical Engineering Process of Ministry of Education, School of Chemical Engineering and Pharmacy, Wuhan Institute of Technology, Wuhan, P. R. China
| | - Shuang Cao
- Key Laboratory of Green Chemical Engineering Process of Ministry of Education, School of Chemical Engineering and Pharmacy, Wuhan Institute of Technology, Wuhan, P. R. China
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9
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Furukawa A, Tanaka A, Yamaguchi S, Kosuda M, Yamana M, Nagasawa A, Kohno G, Ishihara H. Using recombinase-mediated cassette exchange to engineer MIN6 insulin-secreting cells based on a newly identified safe harbor locus. J Diabetes Investig 2021; 12:2129-2140. [PMID: 34382357 PMCID: PMC8668067 DOI: 10.1111/jdi.13646] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 08/03/2021] [Accepted: 08/09/2021] [Indexed: 12/04/2022] Open
Abstract
AIMS/INTRODUCTION Recent studies have identified genomic and transcript level changes along with alterations in insulin secretion in patients with diabetes and in rodent models of diabetes. It is important to establish an efficient system for testing functional consequences of these changes. We aimed to generate such a system using insulin-secreting MIN6 cells. MATERIALS AND METHODS MIN6 cells were first engineered to have a tetracycline-regulated expression system. Then, we used the recombination-mediated cassette exchange strategy to explore the silencing-resistant site in the genome and generated a master cell line based on this site. RESULTS We identified a site 10.5 kbps upstream from the Zxdb gene as a locus that allows homogenous transgene expression from a tetracycline responsible promoter. Placing the Flip/Frt-based platform on this locus using CRISPR/Cas9 technology generated modified MIN6 cells applicable to achieving cassette exchange on the genome. Using this cell line, we generated MIN6 subclones with over- or underexpression of glucokinase. By analyzing a mixed population of these cells, we obtained an initial estimate of effects on insulin secretion within 6 weeks. Furthermore, we generated six MIN6 cell sublines simultaneously harboring genes of inducible overexpression with unknown functions in insulin secretion, and found that Cited4 and Arhgef3 overexpressions increased and decreased insulin secretion, respectively. CONCLUSIONS We engineered MIN6 cells, which can serve as a powerful tool for testing genetic alterations associated with diabetes, and studied the molecular mechanisms of insulin secretion.
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Affiliation(s)
- Asami Furukawa
- Division of Diabetes and Metabolic DiseasesNihon University School of MedicineItabashiJapan
| | - Aya Tanaka
- Division of Diabetes and Metabolic DiseasesNihon University School of MedicineItabashiJapan
| | - Suguru Yamaguchi
- Division of Diabetes and Metabolic DiseasesNihon University School of MedicineItabashiJapan
| | - Minami Kosuda
- Division of Diabetes and Metabolic DiseasesNihon University School of MedicineItabashiJapan
| | - Midori Yamana
- Division of Diabetes and Metabolic DiseasesNihon University School of MedicineItabashiJapan
| | - Akiko Nagasawa
- Division of Diabetes and Metabolic DiseasesNihon University School of MedicineItabashiJapan
| | - Genta Kohno
- Division of Diabetes and Metabolic DiseasesNihon University School of MedicineItabashiJapan
| | - Hisamitsu Ishihara
- Division of Diabetes and Metabolic DiseasesNihon University School of MedicineItabashiJapan
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10
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Wang X, Liang Y, Zhao J, Li Y, Gou S, Zheng M, Zhou J, Zhang Q, Mi J, Lai L. Generation of permanent neonatal diabetes mellitus dogs with glucokinase point mutations through base editing. Cell Discov 2021; 7:92. [PMID: 34635647 PMCID: PMC8505425 DOI: 10.1038/s41421-021-00304-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Accepted: 07/02/2021] [Indexed: 11/18/2022] Open
Affiliation(s)
- Xiaomin Wang
- CAS Key Laboratory of Regenerative Biology, Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China.,Beijing SINOGENE Biotechnology Co., Ltd, Beijing, China.,University of Chinese Academy of Sciences, Beijing, China.,School of Life Sciences, Westlake University, Hangzhou, China
| | - Yanhui Liang
- CAS Key Laboratory of Regenerative Biology, Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China.,Beijing SINOGENE Biotechnology Co., Ltd, Beijing, China.,Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, China.,School of Life Sciences, University of Science and Technology of China, Hefei, China
| | - Jianping Zhao
- Bioland Laboratory (Guangzhou Regenerative Medicine and Health Guangdong Laboratory), Guangzhou, China
| | - Yuan Li
- Bioland Laboratory (Guangzhou Regenerative Medicine and Health Guangdong Laboratory), Guangzhou, China
| | - Shixue Gou
- CAS Key Laboratory of Regenerative Biology, Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China.,Beijing SINOGENE Biotechnology Co., Ltd, Beijing, China.,Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, China.,School of Life Sciences, University of Science and Technology of China, Hefei, China
| | - Min Zheng
- Bioland Laboratory (Guangzhou Regenerative Medicine and Health Guangdong Laboratory), Guangzhou, China
| | - Juanjuan Zhou
- CAS Key Laboratory of Regenerative Biology, Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China.,Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, China.,School of Life Sciences, University of Science and Technology of China, Hefei, China.,Research Unit of Generation of Large Animal Disease Models, Chinese Academy of Medical Sciences (2019RU015), Guangzhou, China
| | - Quanjun Zhang
- CAS Key Laboratory of Regenerative Biology, Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China.,Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, China.,School of Life Sciences, University of Science and Technology of China, Hefei, China
| | - Jidong Mi
- Bioland Laboratory (Guangzhou Regenerative Medicine and Health Guangdong Laboratory), Guangzhou, China.
| | - Liangxue Lai
- CAS Key Laboratory of Regenerative Biology, Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, South China Institute for Stem Cell Biology and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China. .,Institute of Biology, Westlake Institute for Advanced Study, Hangzhou, China. .,School of Life Sciences, University of Science and Technology of China, Hefei, China.
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11
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Nakamura A, Omori K, Terauchi Y. Glucokinase activation or inactivation: Which will lead to the treatment of type 2 diabetes? Diabetes Obes Metab 2021; 23:2199-2206. [PMID: 34105236 DOI: 10.1111/dom.14459] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 05/24/2021] [Accepted: 06/02/2021] [Indexed: 12/14/2022]
Abstract
Glucokinase, which phosphorylates glucose to form glucose-6-phosphate, plays a critical role in regulating blood glucose levels. On the basis of data of glucokinase-knockout and transgenic mice and humans with glucokinase mutations, glucokinase was targeted for drug development aiming to augment its activity, and thereby reduce hyperglycaemia in patients with diabetes. In fact, various small molecule compounds have been developed and clinically tested as glucokinase activators. However, some have been discontinued because of efficacy and safety issues. One of these issues is loss of the drug's efficacy over time. This unsustained glycaemic efficacy may be associated with the excess glycolysis by glucokinase activation in pancreatic beta cells, resulting in beta-cell failure. Recently, we have shown that glucokinase haploinsufficiency ameliorated glucose intolerance by increasing beta-cell function and mass in a mouse model of diabetes. Given that a similar phenotype has been observed in glucokinase-activated beta cells and diabetic beta cells, glucokinase inactivation may be a new therapeutic target for type 2 diabetes.
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Affiliation(s)
- Akinobu Nakamura
- Department of Rheumatology, Endocrinology and Nephrology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Kazuno Omori
- Department of Rheumatology, Endocrinology and Nephrology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Yasuo Terauchi
- Department of Endocrinology and Metabolism, Graduate School of Medicine, Yokohama City University, Yokohama, Japan
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12
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Tsuchida K, Nakamura A, Miyoshi H, Yang K, Yamauchi Y, Kawata S, Omori K, Takahashi K, Kitao N, Nomoto H, Kameda H, Cho KY, Seino Y, Terauchi Y, Atsumi T. Glucokinase is required for high-starch diet-induced β-cell mass expansion in mice. J Diabetes Investig 2021; 12:1545-1554. [PMID: 33638884 PMCID: PMC8409809 DOI: 10.1111/jdi.13532] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 01/27/2021] [Accepted: 02/14/2021] [Indexed: 11/19/2022] Open
Abstract
AIMS/INTRODUCTION We aimed to determine whether glucokinase is required for β-cell mass expansion induced by high-starch diet (HSTD)-feeding, as has been shown in its high-fat diet-induced expansion. MATERIALS AND METHODS Eight-week-old male wild-type (Gck+/+ ) or glucokinase haploinsufficient (Gck+/- ) mice were fed either a normal chow (NC) or an HSTD for 15 weeks. The bodyweight, glucose tolerance, insulin sensitivity, insulin secretion and β-cell mass were assessed. RESULTS Both HSTD-fed Gck+/+ and Gck+/- mice had significantly higher bodyweight than NC-fed mice. Insulin and oral glucose tolerance tests revealed that HSTD feeding did not affect insulin sensitivity nor glucose tolerance in either the Gck+/+ or Gck+/- mice. However, during the oral glucose tolerance test, the 15-min plasma insulin concentration after glucose loading was significantly higher in the HSTD group than that in the NC group for Gck+/+ , but not for Gck+/- mice. β-Cell mass was significantly larger in HSTD-fed Gck+/+ mice than that in NC-fed Gck+/+ mice. In contrast, the β-cell mass of the HSTD-fed Gck+/- mice was not different from that of the NC-fed Gck+/- mice. CONCLUSIONS The results showed that HSTD feeding would increase pancreatic β-cell mass and insulin secretion in Gck+/+ , but not Gck+/- mice. This observation implies that glucokinase in β-cells would be required for the increase in β-cell mass induced by HSTD feeding.
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Affiliation(s)
- Kazuhisa Tsuchida
- Department of Rheumatology, Endocrinology and NephrologyFaculty of Medicine and Graduate School of MedicineHokkaido UniversitySapporoJapan
| | - Akinobu Nakamura
- Department of Rheumatology, Endocrinology and NephrologyFaculty of Medicine and Graduate School of MedicineHokkaido UniversitySapporoJapan
| | - Hideaki Miyoshi
- Division of Diabetes and ObesityFaculty of Medicine and Graduate School of MedicineHokkaido UniversitySapporoJapan
| | - Kelaier Yang
- Department of Rheumatology, Endocrinology and NephrologyFaculty of Medicine and Graduate School of MedicineHokkaido UniversitySapporoJapan
| | - Yuki Yamauchi
- Department of Rheumatology, Endocrinology and NephrologyFaculty of Medicine and Graduate School of MedicineHokkaido UniversitySapporoJapan
| | - Shinichiro Kawata
- Department of Rheumatology, Endocrinology and NephrologyFaculty of Medicine and Graduate School of MedicineHokkaido UniversitySapporoJapan
| | - Kazuno Omori
- Department of Rheumatology, Endocrinology and NephrologyFaculty of Medicine and Graduate School of MedicineHokkaido UniversitySapporoJapan
| | - Kiyohiko Takahashi
- Department of Rheumatology, Endocrinology and NephrologyFaculty of Medicine and Graduate School of MedicineHokkaido UniversitySapporoJapan
| | - Naoyuki Kitao
- Department of Rheumatology, Endocrinology and NephrologyFaculty of Medicine and Graduate School of MedicineHokkaido UniversitySapporoJapan
| | - Hiroshi Nomoto
- Department of Rheumatology, Endocrinology and NephrologyFaculty of Medicine and Graduate School of MedicineHokkaido UniversitySapporoJapan
| | - Hiraku Kameda
- Department of Rheumatology, Endocrinology and NephrologyFaculty of Medicine and Graduate School of MedicineHokkaido UniversitySapporoJapan
| | - Kyu Yong Cho
- Department of Rheumatology, Endocrinology and NephrologyFaculty of Medicine and Graduate School of MedicineHokkaido UniversitySapporoJapan
- Clinical Research and Medical Innovation CenterHokkaido University HospitalSapporoJapan
| | - Yusuke Seino
- Department of Endocrinology and MetabolismGraduate School of MedicineFujita Health UniversityToyoakeJapan
| | - Yasuo Terauchi
- Department of Endocrinology and MetabolismGraduate School of MedicineYokohama City UniversityYokohamaJapan
| | - Tatsuya Atsumi
- Department of Rheumatology, Endocrinology and NephrologyFaculty of Medicine and Graduate School of MedicineHokkaido UniversitySapporoJapan
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13
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Omori K, Nakamura A, Miyoshi H, Yamauchi Y, Kawata S, Takahashi K, Kitao N, Nomoto H, Kameda H, Cho KY, Terauchi Y, Atsumi T. Glucokinase Inactivation Paradoxically Ameliorates Glucose Intolerance by Increasing β-Cell Mass in db/db Mice. Diabetes 2021; 70:917-931. [PMID: 33608422 DOI: 10.2337/db20-0881] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Accepted: 01/22/2021] [Indexed: 11/13/2022]
Abstract
Efficacy of glucokinase activation on glycemic control is limited to a short-term period. One reason might be related to excess glucose signaling by glucokinase activation toward β-cells. In this study, we investigated the effect of glucokinase haploinsufficiency on glucose tolerance as well as β-cell function and mass using a mouse model of type 2 diabetes. Our results showed that in db/db mice with glucokinase haploinsufficiency, glucose tolerance was ameliorated by augmented insulin secretion associated with the increase in β-cell mass when compared with db/db mice. Gene expression profiling and immunohistochemical and metabolomic analyses revealed that glucokinase haploinsufficiency in the islets of db/db mice was associated with lower expression of stress-related genes, greater expression of transcription factors involved in the maintenance and maturation of β-cell function, less mitochondrial damage, and a superior metabolic pattern. These effects of glucokinase haploinsufficiency could preserve β-cell mass under diabetic conditions. These findings verified our hypothesis that optimizing excess glucose signaling in β-cells by inhibiting glucokinase could prevent β-cell insufficiency, leading to improving glucose tolerance in diabetes status by preserving β-cell mass. Therefore, glucokinase inactivation in β-cells, paradoxically, could be a potential strategy for the treatment of type 2 diabetes.
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Affiliation(s)
- Kazuno Omori
- Department of Rheumatology, Endocrinology, and Nephrology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Akinobu Nakamura
- Department of Rheumatology, Endocrinology, and Nephrology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Hideaki Miyoshi
- Division of Diabetes and Obesity, Faculty of Medicine and Graduate School of Medicine Hokkaido University, Sapporo, Japan
| | - Yuki Yamauchi
- Department of Rheumatology, Endocrinology, and Nephrology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Shinichiro Kawata
- Department of Rheumatology, Endocrinology, and Nephrology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Kiyohiko Takahashi
- Department of Rheumatology, Endocrinology, and Nephrology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Naoyuki Kitao
- Department of Rheumatology, Endocrinology, and Nephrology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Hiroshi Nomoto
- Department of Rheumatology, Endocrinology, and Nephrology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Hiraku Kameda
- Department of Rheumatology, Endocrinology, and Nephrology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Kyu Yong Cho
- Department of Rheumatology, Endocrinology, and Nephrology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan
- Clinical Research and Medical Innovation Center, Hokkaido University Hospital, Sapporo, Japan
| | - Yasuo Terauchi
- Department of Endocrinology and Metabolism, Graduate School of Medicine, Yokohama City University, Yokohama, Japan
| | - Tatsuya Atsumi
- Department of Rheumatology, Endocrinology, and Nephrology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Sapporo, Japan
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14
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Sanchez Caballero L, Gorgogietas V, Arroyo MN, Igoillo-Esteve M. Molecular mechanisms of β-cell dysfunction and death in monogenic forms of diabetes. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2021; 359:139-256. [PMID: 33832649 DOI: 10.1016/bs.ircmb.2021.02.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Monogenetic forms of diabetes represent 1%-5% of all diabetes cases and are caused by mutations in a single gene. These mutations, that affect genes involved in pancreatic β-cell development, function and survival, or insulin regulation, may be dominant or recessive, inherited or de novo. Most patients with monogenic diabetes are very commonly misdiagnosed as having type 1 or type 2 diabetes. The severity of their symptoms depends on the nature of the mutation, the function of the affected gene and, in some cases, the influence of additional genetic or environmental factors that modulate severity and penetrance. In some patients, diabetes is accompanied by other syndromic features such as deafness, blindness, microcephaly, liver and intestinal defects, among others. The age of diabetes onset may also vary from neonatal until early adulthood manifestations. Since the different mutations result in diverse clinical presentations, patients usually need different treatments that range from just diet and exercise, to the requirement of exogenous insulin or other hypoglycemic drugs, e.g., sulfonylureas or glucagon-like peptide 1 analogs to control their glycemia. As a consequence, awareness and correct diagnosis are crucial for the proper management and treatment of monogenic diabetes patients. In this chapter, we describe mutations causing different monogenic forms of diabetes associated with inadequate pancreas development or impaired β-cell function and survival, and discuss the molecular mechanisms involved in β-cell demise.
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Affiliation(s)
- Laura Sanchez Caballero
- ULB Center for Diabetes Research (UCDR), Université Libre de Bruxelles, Brussels, Belgium. http://www.ucdr.be/
| | - Vyron Gorgogietas
- ULB Center for Diabetes Research (UCDR), Université Libre de Bruxelles, Brussels, Belgium. http://www.ucdr.be/
| | - Maria Nicol Arroyo
- ULB Center for Diabetes Research (UCDR), Université Libre de Bruxelles, Brussels, Belgium. http://www.ucdr.be/
| | - Mariana Igoillo-Esteve
- ULB Center for Diabetes Research (UCDR), Université Libre de Bruxelles, Brussels, Belgium. http://www.ucdr.be/.
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15
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Lipták N, Gál Z, Biró B, Hiripi L, Hoffmann OI. Rescuing lethal phenotypes induced by disruption of genes in mice: a review of novel strategies. Physiol Res 2021; 70:3-12. [PMID: 33453719 DOI: 10.33549/physiolres.934543] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Approximately 35 % of the mouse genes are indispensable for life, thus, global knock-out (KO) of those genes may result in embryonic or early postnatal lethality due to developmental abnormalities. Several KO mouse lines are valuable human disease models, but viable homozygous mutant mice are frequently required to mirror most symptoms of a human disease. The site-specific gene editing systems, the transcription activator-like effector nucleases (TALENs), Zinc-finger nucleases (ZFNs) and the clustered regularly interspaced short palindrome repeat-associated Cas9 nuclease (CRISPR/Cas9) made the generation of KO mice more efficient than before, but the homozygous lethality is still an undesired side-effect in case of many genes. The literature search was conducted using PubMed and Web of Science databases until June 30th, 2020. The following terms were combined to find relevant studies: "lethality", "mice", "knock-out", "deficient", "embryonic", "perinatal", "rescue". Additional manual search was also performed to find the related human diseases in the Online Mendelian Inheritance in Man (OMIM) database and to check the citations of the selected studies for rescuing methods. In this review, the possible solutions for rescuing human disease-relevant homozygous KO mice lethal phenotypes were summarized.
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Affiliation(s)
- N Lipták
- NARIC-Agricultural Biotechnology Institute, Animal Biotechnology Department, Gödöllő, Hungary.
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16
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Hulín J, Škopková M, Valkovičová T, Mikulajová S, Rosoľanková M, Papcun P, Gašperíková D, Staník J. Clinical implications of the glucokinase impaired function - GCK MODY today. Physiol Res 2020; 69:995-1011. [PMID: 33129248 DOI: 10.33549/physiolres.934487] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Heterozygous inactivating mutations of the glucokinase (GCK) gene are causing GCK-MODY, one of the most common forms of the Maturity Onset Diabetes of the Young (MODY). GCK-MODY is characterized by fasting hyperglycemia without apparent worsening with aging and low risk for chronic vascular complications. Despite the mild clinical course, GCK-MODY could be misdiagnosed as type 1 or type 2 diabetes. In the diagnostic process, the clinical suspicion is often based on the clinical diagnostic criteria for GCK-MODY and should be confirmed by DNA analysis. However, there are several issues in the clinical and also in genetic part that could complicate the diagnostic process. Most of the people with GCK-MODY do not require any pharmacotherapy. The exception are pregnant women with a fetus which did not inherit GCK mutation from the mother. Such a child has accelerated growth, and has increased risk for diabetic foetopathy. In this situation the mother should be treated with substitutional doses of insulin. Therefore, distinguishing GCK-MODY from gestational diabetes in pregnancy is very important. For this purpose, special clinical diagnostic criteria for clinical identification of GCK-MODY in pregnancy are used. This review updates information on GCK-MODY and discusses several currently not solved problems in the clinical diagnostic process, genetics, and treatment of this type of monogenic diabetes.
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Affiliation(s)
- J Hulín
- Department of Pediatrics, Medical Faculty of the Comenius University, Bratislava, Slovakia.
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17
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Song Y, Sui T, Zhang Y, Wang Y, Chen M, Deng J, Chai Z, Lai L, Li Z. Genetic deletion of a short fragment of glucokinase in rabbit by CRISPR/Cas9 leading to hyperglycemia and other typical features seen in MODY-2. Cell Mol Life Sci 2020; 77:3265-3277. [PMID: 31720743 PMCID: PMC11105094 DOI: 10.1007/s00018-019-03354-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Revised: 10/22/2019] [Accepted: 10/23/2019] [Indexed: 01/11/2023]
Abstract
Glucokinase (GCK) is a key enzyme in glucose sensing and glycemic regulation. In humans, mutations in the GCK gene cause maturity-onset diabetes of the young 2 (MODY-2), a disease that is characterized by an early-onset and persistent hyperglycemia. It is known that Gck knockout (KO) is lethal in mice with Gck KO mice dying within 2 weeks after birth. Therefore, Gck KO mice are not suitable for preclinical study and have limited suitability to study the pathophysiological role of glucokinase in vivo. Here, we report the generation of a novel rabbit with a non-frameshift mutation of GCK gene (GCK-NFS) by cytoplasm microinjection of Cas9 mRNA and gRNA. These GCK-NFS rabbits showed typical features of MODY-2 including hyperglycemia and glucose intolerance with similar survival rate and weight compared to wild-type (WT) rabbits. The diabetic phenotype including pancreatic and renal dysfunction was also found in the F1-generation rabbits, indicating that the genetic modification is germline transmissible. Treatment of GCK-NFS rabbit with glimepiride successfully reduced the fasting blood glucose drastically and improved its islet function. In conclusion, this novel GCK mutant rabbit generated with the CRISPR/Cas9 system mimics most, if not all, histopathological and functional defects seen in MODY-2 patients such as hyperglycemia and will be a valuable rabbit model for preclinical studies and drug screening for diabetes as well as for studying the pathophysiological role of glucokinase.
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Affiliation(s)
- Yuning Song
- Jilin Provincial Key Laboratory of Animal Embryo Engineering, Jilin University, Changchun, 130062, China
| | - Tingting Sui
- Jilin Provincial Key Laboratory of Animal Embryo Engineering, Jilin University, Changchun, 130062, China
| | - Yuxin Zhang
- Jilin Provincial Key Laboratory of Animal Embryo Engineering, Jilin University, Changchun, 130062, China
| | - Yong Wang
- Jilin Provincial Key Laboratory of Animal Embryo Engineering, Jilin University, Changchun, 130062, China
| | - Mao Chen
- Jilin Provincial Key Laboratory of Animal Embryo Engineering, Jilin University, Changchun, 130062, China
| | - Jichao Deng
- Jilin Provincial Key Laboratory of Animal Embryo Engineering, Jilin University, Changchun, 130062, China
| | - Zhonglin Chai
- Department of Diabetes, Central Clinical School, Pathophysiology of Diabetic Complications Laboratory, Monash University, Melbourne, Australia
| | - Liangxue Lai
- Jilin Provincial Key Laboratory of Animal Embryo Engineering, Jilin University, Changchun, 130062, China.
| | - Zhanjun Li
- Jilin Provincial Key Laboratory of Animal Embryo Engineering, Jilin University, Changchun, 130062, China.
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18
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Shariati K, Pappalardo Z, Chopra DG, Yiv N, Sheen R, Ku G. Selective monitoring of insulin secretion after CRISPR interference in intact pancreatic islets despite submaximal infection. Islets 2020; 12:59-69. [PMID: 32579048 PMCID: PMC7527018 DOI: 10.1080/19382014.2020.1752072] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Virus-mediated gene knockdown in intact pancreatic islets is technically challenging due to poor infection of the center of the islet. Because the cells that do not have knockdown have normal insulin secretion, measuring changes in insulin secretion after gene knockdown is challenging. We describe a method to monitor insulin secretion from only the beta cells with knockdown of a gene of interest in intact islets using a single lentivirus containing a guide RNA, a luciferase insulin secretion reporter and a dCas9-KRAB cassette. This method allows rapid and inexpensive monitoring of insulin secretion from only those beta cells with knockdown, circumventing the problem of incomplete islet infection.
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Affiliation(s)
| | | | | | | | - Robin Sheen
- Diabetes Center, UCSF, San Francisco, CA, USA
| | - Gregory Ku
- Diabetes Center, UCSF, San Francisco, CA, USA
- Division of Endocrinology and Metabolism, Department of Medicine, UCSF, San Francisco, CA, USA
- CONTACT Gregory Ku 513 Parnassus Ave., San Francisco, CA94143
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19
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Wu P, Liu Z, Jiang X, Fang H. An Overview of Prospective Drugs for Type 1 and Type 2 Diabetes. Curr Drug Targets 2020; 21:445-457. [PMID: 31670620 DOI: 10.2174/1389450120666191031104653] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2019] [Revised: 10/07/2019] [Accepted: 10/16/2019] [Indexed: 12/14/2022]
Abstract
Aims:
The aim of this study is to provide an overview of several emerging anti-diabetic
molecules.
Background:
Diabetes is a complex metabolic disorder involving the dysregulation of glucose homeostasis
at various levels. Insulin, which is produced by β-pancreatic cells, is a chief regulator of glucose
metabolism, regulating its consumption within cells, which leads to energy generation or storage as glycogen.
Abnormally low insulin secretion from β-cells, insulin insensitivity, and insulin tolerance lead to
higher plasma glucose levels, resulting in metabolic complications. The last century has witnessed extraordinary
efforts by the scientific community to develop anti-diabetic drugs, and these efforts have resulted
in the discovery of exogenous insulin and various classes of oral anti-diabetic drugs.
Objective:
Despite these exhaustive anti-diabetic pharmaceutical and therapeutic efforts, long-term
glycemic control, hypoglycemic crisis, safety issues, large-scale economic burden and side effects remain
the core problems.
Method:
The last decade has witnessed the development of various new classes of anti-diabetic drugs
with different pharmacokinetic and pharmacodynamic profiles. Details of their FDA approvals and
advantages/disadvantages are summarized in this review.
Results:
The salient features of insulin degludec, sodium-glucose co-transporter 2 inhibitors, glucokinase
activators, fibroblast growth factor 21 receptor agonists, and GLP-1 agonists are discussed.
Conclusion :
In the future, these new anti-diabetic drugs may have broad clinical applicability. Additional
multicenter clinical studies on these new drugs should be conducted.
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Affiliation(s)
- Ping Wu
- Department of Pharmacology, 3rd Affiliated Hospital, Soochow University, Changzhou, Jiangsu Province, China
| | - Zhenyu Liu
- Department of Endocrinology, 3rd Affiliated Hospital, Soochow University, Changzhou, Jiangsu Province, China
| | - Xiaohong Jiang
- Department of Endocrinology, 3rd Affiliated Hospital, Soochow University, Changzhou, Jiangsu Province, China
| | - Hao Fang
- Department of Pharmacology, 3rd Affiliated Hospital, Soochow University, Changzhou, Jiangsu Province, China
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20
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Kyohara M, Shirakawa J, Okuyama T, Togashi Y, Inoue R, Li J, Miyashita D, Terauchi Y. Soluble EGFR, a hepatokine, and adipsin, an adipokine, are biomarkers correlated with distinct aspects of insulin resistance in type 2 diabetes subjects. Diabetol Metab Syndr 2020; 12:83. [PMID: 33005239 PMCID: PMC7526230 DOI: 10.1186/s13098-020-00591-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2020] [Accepted: 09/22/2020] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Insulin resistance can occur in all metabolic organs including the liver, adipose tissue, and skeletal muscles. Circulating soluble epidermal growth factor receptor (soluble EGFR) and adipsin levels are altered in obese diabetic mice and are possibly correlated with insulin resistance in both mice and humans. Here, we investigated the significance of soluble EGFR and adipsin as biomarkers for insulin resistance in Japanese subjects with type 2 diabetes. METHODS We measured the soluble EGFR and adipsin levels in sera from 47 non-diabetic subjects and 106 subjects with type 2 diabetes using enzyme-linked immunosorbent assays (ELISAs) and analyzed the correlations between the soluble EGFR or adipsin levels and metabolic parameters in type 2 diabetes subjects. We also measured the gene expression levels of Egfr and Cfd (adipsin) in the liver, adipose tissue, and skeletal muscle in mice with/without obesity or diabetes. RESULTS The soluble EGFR levels were correlated with the fasting blood glucose level (P = 0.010), HOMA-IR (P = 0.035), HbA1c level (P = 0.007), HDL-cholesterol level (P = 0.044), and FIB-4 index (P = 0.017) after adjustments for age, sex, and total cholesterol levels. These factors are known to be related to hepatic insulin resistance. The serum adipsin levels were correlated with BMI (P < 0.001), waist circumference (P < 0.001), fasting serum insulin level (P = 0.001), HOMA-IR (P = 0.009), CPR-index (P = 0.045), and FIB-4 index (P = 0.007) after adjustments for age, sex and eGFR levels. Abdominal adiposity leads to the potentiation of these factors. The expression of Egfr was abundant in the liver, while Cfd was predominantly expressed in adipose tissue in mice. CONCLUSIONS Soluble EGFR, a hepatokine, is correlated with insulin resistance in the liver, while adipsin, an adipokine, is associated with adipose insulin resistance.Trial registration: UMIN Clinical Trials Registry (www.umin.ac.jp), UMIN000020474. Registered 8 January 2016.
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Affiliation(s)
- Mayu Kyohara
- Department of Endocrinology and Metabolism, Graduate School of Medicine, Yokohama-City University, 3-9 Fukuura, Yokohama, 236-0004 Japan
| | - Jun Shirakawa
- Department of Endocrinology and Metabolism, Graduate School of Medicine, Yokohama-City University, 3-9 Fukuura, Yokohama, 236-0004 Japan
- Laboratory of Diabetes and Metabolic Disorders, Institute for Molecular and Cellular Regulation (IMCR), Gunma University, 3-39-15 Showa-machi, Maebashi, 371-8512 Japan
| | - Tomoko Okuyama
- Department of Endocrinology and Metabolism, Graduate School of Medicine, Yokohama-City University, 3-9 Fukuura, Yokohama, 236-0004 Japan
| | - Yu Togashi
- Department of Endocrinology and Metabolism, Graduate School of Medicine, Yokohama-City University, 3-9 Fukuura, Yokohama, 236-0004 Japan
| | - Ryota Inoue
- Department of Endocrinology and Metabolism, Graduate School of Medicine, Yokohama-City University, 3-9 Fukuura, Yokohama, 236-0004 Japan
- Laboratory of Diabetes and Metabolic Disorders, Institute for Molecular and Cellular Regulation (IMCR), Gunma University, 3-39-15 Showa-machi, Maebashi, 371-8512 Japan
| | - Jinghe Li
- Department of Endocrinology and Metabolism, Graduate School of Medicine, Yokohama-City University, 3-9 Fukuura, Yokohama, 236-0004 Japan
- Laboratory of Diabetes and Metabolic Disorders, Institute for Molecular and Cellular Regulation (IMCR), Gunma University, 3-39-15 Showa-machi, Maebashi, 371-8512 Japan
| | - Daisuke Miyashita
- Department of Endocrinology and Metabolism, Graduate School of Medicine, Yokohama-City University, 3-9 Fukuura, Yokohama, 236-0004 Japan
| | - Yasuo Terauchi
- Department of Endocrinology and Metabolism, Graduate School of Medicine, Yokohama-City University, 3-9 Fukuura, Yokohama, 236-0004 Japan
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21
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Ryu JC, Zimmer ER, Rosa-Neto P, Yoon SO. Consequences of Metabolic Disruption in Alzheimer's Disease Pathology. Neurotherapeutics 2019; 16:600-610. [PMID: 31270743 PMCID: PMC6694332 DOI: 10.1007/s13311-019-00755-y] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Alzheimer's disease (AD) is an irreversible, progressive disease that slowly destroys cognitive function, such as thinking, remembering, and reasoning, to a level that one cannot carry out a daily living. As people live longer, the risk of developing AD has increased to 1 in 10 among people who are older than 65 and to almost 1 in 2 among those who are older than 85 according to a 2019 Alzheimer's Association report. As a most common cause of dementia, AD accounts for 60-80% of all dementia cases. AD is characterized by amyloid plaques and neurofibrillary tangles, composed of extracellular aggregates of amyloid-β peptides and intracellular aggregates of hyperphosphorylated tau, respectively. Besides plaques and tangles, AD pathology includes synaptic dysfunction including loss of synapses, inflammation, brain atrophy, and brain hypometabolism, all of which contribute to progressive cognitive decline. Recent genetic studies of sporadic cases of AD have identified a score of risk factors, as reported by Hollingworth et al. (Nat Genet 43:429-435, 2001) and Lambert et al. (Nat Genet 45:1452-1458, 2013). Of all these genes, apolipoprotein E4 (APOE4) still presents the biggest risk factor for sporadic cases of AD, as stated in Saunders et al. (Neurology 43:1467-1472, 1993): depending on whether you have 1 or 2 copies of APOE4 allele, the risk increases from 3- to 12-fold, respectively, in line with Genin et al. (Mol Psychiatry 16:903-907, 2011). Besides these genetic risk factors, having type 2 diabetes (T2D), a chronic metabolic disease, is known to increase the AD risk by at least 2-fold when these individuals age, conforming to Sims-Robinson et al. (Nat Rev Neurol 6:551-559, 2010). Diabetes is reaching a pandemic scale with over 422 million people diagnosed worldwide in 2014 according to World Health Organization. Although what proportion of these diabetic patients develop AD is not known, even if 10% of diabetic patients develop AD later in their life, it would double the number of AD patients in the world. Better understanding between T2D and AD is of paramount of importance for the future. The goal of this review is to examine our current understanding on metabolic dysfunction in AD, so that a potential target can be identified in the near future.
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Affiliation(s)
- J C Ryu
- Department of Biological Chemistry & Pharmacology, Ohio State University, Columbus, OH, USA
| | - E R Zimmer
- Department of Pharmacology, UFRGS, Porto Alegre, Brazil
- Graduate Program in Biological Sciences: Biochemistry, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil
- Graduate Program in Biological Sciences: Pharmacology and Therapeutics, UFRGS, Porto Alegre, Brazil
- Brain Institute of Rio Grande do Sul (BraIns), Pontifical Catholic University of Rio Grande do Sul, Porto Alegre, Brazil
| | - P Rosa-Neto
- Montreal Neurological Institute, Montreal, Canada
| | - S O Yoon
- Department of Biological Chemistry & Pharmacology, Ohio State University, Columbus, OH, USA.
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22
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Matschinsky FM, Wilson DF. The Central Role of Glucokinase in Glucose Homeostasis: A Perspective 50 Years After Demonstrating the Presence of the Enzyme in Islets of Langerhans. Front Physiol 2019; 10:148. [PMID: 30949058 PMCID: PMC6435959 DOI: 10.3389/fphys.2019.00148] [Citation(s) in RCA: 140] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Accepted: 02/07/2019] [Indexed: 01/05/2023] Open
Abstract
It is hypothesized that glucokinase (GCK) is the glucose sensor not only for regulation of insulin release by pancreatic β-cells, but also for the rest of the cells that contribute to glucose homeostasis in mammals. This includes other cells in endocrine pancreas (α- and δ-cells), adrenal gland, glucose sensitive neurons, entero-endocrine cells, and cells in the anterior pituitary. Glucose transport is by facilitated diffusion and is not rate limiting. Once inside, glucose is phosphorylated to glucose-6-phosphate by GCK in a reaction that is dependent on glucose throughout the physiological range of concentrations, is irreversible, and not product inhibited. High glycerol phosphate shuttle, pyruvate dehydrogenase, and pyruvate carboxylase activities, combined with low pentose-P shunt, lactate dehydrogenase, plasma membrane monocarboxylate transport, and glycogen synthase activities constrain glucose-6-phosphate to being metabolized through glycolysis. Under these conditions, glycolysis produces mostly pyruvate and little lactate. Pyruvate either enters the citric acid cycle through pyruvate dehydrogenase or is carboxylated by pyruvate carboxylase. Reducing equivalents from glycolysis enter oxidative phosphorylation through both the glycerol phosphate shuttle and citric acid cycle. Raising glucose concentration increases intramitochondrial [NADH]/[NAD+] and thereby the energy state ([ATP]/[ADP][Pi]), decreasing [Mg2+ADP] and [AMP]. [Mg2+ADP] acts through control of KATP channel conductance, whereas [AMP] acts through regulation of AMP-dependent protein kinase. Specific roles of different cell types are determined by the diverse molecular mechanisms used to couple energy state to cell specific responses. Having a common glucose sensor couples complementary regulatory mechanisms into a tightly regulated and stable glucose homeostatic network.
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Affiliation(s)
- Franz M Matschinsky
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - David F Wilson
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
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23
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Wang N, Li S, Guo XC, Li JY, Ren GP, Li DS. Fibroblast growth factor 21 improves glucose homeostasis partially via down-regulation of Na +-d-glucose cotransporter SGLT1 in the small intestine. Biomed Pharmacother 2018; 109:1070-1077. [PMID: 30551357 DOI: 10.1016/j.biopha.2018.10.198] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Revised: 10/26/2018] [Accepted: 10/31/2018] [Indexed: 12/15/2022] Open
Abstract
Fibroblast growth factor-21 (FGF-21), an endocrine hormone, is regarded as a therapeutic target for diabetes base on its potent effects on improving hyperglycemia. Sodium-dependent glucose cotransporter 1 (SGLT1) is mainly expressed in the small intestine (SI) for intestinal glucose absorption. It has been demonstrated that SGLT1 expression is increased in diabetes, which is thought to contribute to the rapidly rising postprandial blood glucose levels. Thus, we aim to examine whether FGF-21 regulates expression of intestinal SGLT1 in diabetes. The db/db mice were treated with insulin, low and high dose of FGF-21 for 5 weeks and then measured changes in glucose metabolism, intestinal glucose absorption and SGLT1 expression. The results showed that FGF-21 improved glucose homeostasis, inhibited intestinal glucose uptake and reduced intestinal SGLT1 expression compared with insulin in db/db mice. To further explore the mechanism of effects of FGF-21 on SGLT1 expression. The murine intestinal epithelial MODE-K cells were treated with FGF-21 for 3 h, 6 h, 12 h and 24 h and then measured glucose uptake, SGLT1 expression, another glucose transporter GLUT2 expression and associated mechanism. Our results showed that FGF-21 inhibited glucose uptake and reduced SGLT1 expression in MODE-K cells, which were due to inactivating SGK-1 pathway. Moreover, above effects of FGF-21 on MODE-K cells were abolished by PD173074, a FGFR1 inhibitor. In conclusion, FGF-21 regulates glucose level in diabetes partially due to inhibiting glucose absorption in the SI via inactivating SGK-1 pathway. These results expand our knowledge about how FGF-21 regulates glucose metabolism.
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Affiliation(s)
- Nan Wang
- Biopharmaceutical Lab, Life Science college, Northeast Agricultural University, Harbin 150030, China
| | - Shuai Li
- Biopharmaceutical Lab, Life Science college, Northeast Agricultural University, Harbin 150030, China
| | - Xiao-Chen Guo
- Biopharmaceutical Lab, Life Science college, Northeast Agricultural University, Harbin 150030, China
| | - Jun-Yan Li
- Biopharmaceutical Lab, Life Science college, Northeast Agricultural University, Harbin 150030, China
| | - Gui-Ping Ren
- Biopharmaceutical Lab, Life Science college, Northeast Agricultural University, Harbin 150030, China; Key Laboratory of Agricultural Biological Functional Gene, Northeast Agricultural University, Harbin, 150030, China
| | - De-Shan Li
- Biopharmaceutical Lab, Life Science college, Northeast Agricultural University, Harbin 150030, China; Key Laboratory of Agricultural Biological Functional Gene, Northeast Agricultural University, Harbin, 150030, China.
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24
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Kitao N, Nakamura A, Miyoshi H, Nomoto H, Takahashi K, Omori K, Yamamoto K, Cho KY, Terauchi Y, Atsumi T. The role of glucokinase and insulin receptor substrate-2 in the proliferation of pancreatic beta cells induced by short-term high-fat diet feeding in mice. Metabolism 2018; 85:48-58. [PMID: 29544862 DOI: 10.1016/j.metabol.2018.03.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Revised: 02/20/2018] [Accepted: 03/08/2018] [Indexed: 12/11/2022]
Abstract
OBJECTIVE We investigated whether glucokinase and insulin receptor substrate-2 were required for beta cell proliferation induced by short-term high-fat (HF) diet feeding, as has been shown for long-term HF diet. METHODS Eight-week-old C57BL/6J mice were exposed to either a standard chow (SC) or HF diet. After 1 week on the diet, histopathological beta cell proliferation and gene expression in isolated islets were examined. Additionally, 8-week-old beta cell-specific glucokinase haploinsufficient (Gck+/-) and Irs2 knockout (Irs2-/-) mice were exposed to either an SC or HF diet. RESULTS Immunohistochemical analysis revealed that short-term HF diet feeding resulted in a significant increase in BrdU incorporation rate compared with SC consumption in wild-type mice. Western blot analysis demonstrated that Irs2 expression levels did not differ between the two diets. Moreover, there was a significant increase in the BrdU incorporation rate in the HF diet group compared with the SC group in both Gck+/- and Irs2-/- mice. Gene expression profiling of isolated islets from mice fed an HF diet for 1 week revealed that the expression levels of downstream genes of Foxm1 were coordinately upregulated. One week of HF diet feeding stimulated beta cell proliferation with Foxm1 upregulation in 48-week-old mice as well as in 8-week-old. CONCLUSIONS The mechanism of pancreatic beta cell proliferation induced by short-term HF diet feeding in mice could involve a glucokinase- and Irs2-independent pathway. Our results suggest that the pathways that induce beta cell proliferation in response to short-term HF diet feeding may differ from those in response to sustained HF diet feeding.
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Affiliation(s)
- Naoyuki Kitao
- Department of Rheumatology, Endocrinology and Nephrology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | - Akinobu Nakamura
- Department of Rheumatology, Endocrinology and Nephrology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University Graduate School of Medicine, Sapporo, Japan.
| | - Hideaki Miyoshi
- Department of Rheumatology, Endocrinology and Nephrology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | - Hiroshi Nomoto
- Department of Rheumatology, Endocrinology and Nephrology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | - Kiyohiko Takahashi
- Department of Rheumatology, Endocrinology and Nephrology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | - Kazuno Omori
- Department of Rheumatology, Endocrinology and Nephrology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | - Kohei Yamamoto
- Department of Rheumatology, Endocrinology and Nephrology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | - Kyu Yong Cho
- Department of Rheumatology, Endocrinology and Nephrology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | - Yasuo Terauchi
- Department of Endocrinology and Metabolism, Graduate School of Medicine, Yokohama City University, Japan
| | - Tatsuya Atsumi
- Department of Rheumatology, Endocrinology and Nephrology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University Graduate School of Medicine, Sapporo, Japan
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25
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Takahashi I, Yamada S, Nata K. Effects of heparan sulfate proteoglycan syndecan-4 on the insulin secretory response in a mouse pancreatic β-cell line, MIN6. Mol Cell Endocrinol 2018; 470:142-150. [PMID: 29042251 DOI: 10.1016/j.mce.2017.10.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Revised: 10/04/2017] [Accepted: 10/13/2017] [Indexed: 01/03/2023]
Abstract
Heparan sulfate proteoglycans (HSPGs) comprise a core protein to which extracellular glycosaminoglycan chains are attached. Syndecan-4, one of the major HS-containing core proteins, is distributed on the cell surface, where they interact with various protein ligands and regulate a wide range of biological activities. Here, we propose that the core protein of HSPGs is involved in the insulin secretory response. To investigate the participation of HSPGs in the insulin-secretion mechanism, MIN6 cells, a mouse pancreatic β-cell line, were subcloned. The subcloned MIN6 cells were selected based on their insulin secretory response, the expression of HS and core proteins. The results from these screening experiments indicated that only syndecan-4-expressing subclones are able to secrete insulin in response to glucose. Silencing of syndecan-4 reduced glucose-induced insulin secretion, whereas the overexpression of syndecan-4 increased the insulin secretory response. These data indicate that the HSPG syndecan-4 plays important role(s) in the insulin secretory response.
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Affiliation(s)
- Iwao Takahashi
- Department of Medical Biochemistry, School of Pharmacy, Iwate Medical University, Yahaba 028-3603, Japan.
| | - Shuhei Yamada
- Department of Pathobiochemistry, Faculty of Pharmacy, Meijo University, Nagoya 468-8503, Japan.
| | - Koji Nata
- Department of Medical Biochemistry, School of Pharmacy, Iwate Medical University, Yahaba 028-3603, Japan.
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26
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Lu B, Kurmi K, Munoz-Gomez M, Jacobus Ambuludi EJ, Tonne JM, Rakshit K, Hitosugi T, Kudva YC, Matveyenko AV, Ikeda Y. Impaired β-cell glucokinase as an underlying mechanism in diet-induced diabetes. Dis Model Mech 2018; 11:dmm033316. [PMID: 29915142 PMCID: PMC6031355 DOI: 10.1242/dmm.033316] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Accepted: 04/26/2018] [Indexed: 12/22/2022] Open
Abstract
High-fat diet (HFD)-fed mouse models have been widely used to study early type 2 diabetes. Decreased β-cell glucokinase (GCK) expression has been observed in HFD-induced diabetes. However, owing to its crucial roles in glucose metabolism in the liver and in islet β-cells, the contribution of decreased GCK expression to the development of HFD-induced diabetes is unclear. Here, we employed a β-cell-targeted gene transfer vector and determined the impact of β-cell-specific increase in GCK expression on β-cell function and glucose handling in vitro and in vivo Overexpression of GCK enhanced glycolytic flux, ATP-sensitive potassium channel activation and membrane depolarization, and increased proliferation in Min6 cells. β-cell-targeted GCK transduction did not change glucose handling in chow-fed C57BL/6 mice. Although adult mice fed a HFD showed reduced islet GCK expression, impaired glucose tolerance and decreased glucose-stimulated insulin secretion (GSIS), β-cell-targeted GCK transduction improved glucose tolerance and restored GSIS. Islet perifusion experiments verified restored GSIS in isolated HFD islets by GCK transduction. Thus, our data identify impaired β-cell GCK expression as an underlying mechanism for dysregulated β-cell function and glycemic control in HFD-induced diabetes. Our data also imply an etiological role of GCK in diet-induced diabetes.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Brian Lu
- Department of Molecular Medicine, Mayo Clinic, Rochester, MN 55905, USA
- Virology and Gene Therapy Graduate Program, Mayo Clinic Graduate School of Biomedical Sciences, Rochester, MN 55905, USA
| | - Kiran Kurmi
- Department of Molecular Medicine, Mayo Clinic, Rochester, MN 55905, USA
- Molecular Pharmacology and Experimental Therapeutics Graduate Program, Mayo Clinic Graduate School of Biomedical Sciences, Rochester, MN 55905, USA
| | | | | | - Jason M Tonne
- Department of Molecular Medicine, Mayo Clinic, Rochester, MN 55905, USA
| | - Kuntol Rakshit
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN 55905, USA
| | - Taro Hitosugi
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN 55905, USA
| | - Yogish C Kudva
- Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Mayo Clinic, Rochester, MN 55905, USA
| | - Aleksey V Matveyenko
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN 55905, USA
| | - Yasuhiro Ikeda
- Department of Molecular Medicine, Mayo Clinic, Rochester, MN 55905, USA
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27
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Zhang J, Weng W, Wang K, Lu X, Cai L, Sun J. The role of FGF21 in type 1 diabetes and its complications. Int J Biol Sci 2018; 14:1000-1011. [PMID: 29989062 PMCID: PMC6036735 DOI: 10.7150/ijbs.25026] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Accepted: 04/21/2018] [Indexed: 02/06/2023] Open
Abstract
Data from the International Diabetes Federation show that 347 million people worldwide have diabetes, and the incidence is still rising. Although the treatment of diabetes has been advanced, the current therapeutic options and outcomes, e.g. complications, are yet far from ideal. Therefore, an urgent need exists for the development of more effective therapies. Numerous studies have been conducted to establish and confirm whether FGF21 exerts beneficial effects on obesity and diabetes along with its complications. However, most of the studies associated with FGF21 were conducted in the patients with type 2 diabetes. Subsequently, the effect of FGF21 in the prevention or treatment of type 1 diabetes and its complications were also increasingly reported. In this review, we summarize the findings available on the function of FGF21 and the status of FGF21's treatment for type 1 diabetes. Based on the available information, we found that FGF21 exerts a hypoglycemic effect, restores the function of brown fat, and inhibits various complications in type 1 diabetes patients. Although these features are predominantly similar to those observed in the studies that showed the beneficial impact of FGF21 on type 2 diabetes and its complications, there are also certain distinct features and findings that may be of provide important and instructive for us to understand mechanistic insights and further promote the prevention and treatment of type 1 diabetes.
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Affiliation(s)
- Jian Zhang
- The Center of Cardiovascular Disorders, the First Hospital of Jilin University, Changchun, China.,Pediatrics Research Institute, Department of Pediatrics, University of Louisville, Louisville, Kentucky, USA
| | - Wenya Weng
- The Third Affiliated Hospital of Wenzhou Medical University, Ruian Center of Chinese-American Research Institute for Diabetic Complications, Ruian, China
| | - Kai Wang
- Pediatrics Research Institute, Department of Pediatrics, University of Louisville, Louisville, Kentucky, USA.,The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Xuemian Lu
- The Third Affiliated Hospital of Wenzhou Medical University, Ruian Center of Chinese-American Research Institute for Diabetic Complications, Ruian, China
| | - Lu Cai
- Pediatrics Research Institute, Department of Pediatrics, University of Louisville, Louisville, Kentucky, USA.,Department of Pharmacology and Toxicology, University of Louisville, Louisville, Kentucky, USA
| | - Jian Sun
- The Center of Cardiovascular Disorders, the First Hospital of Jilin University, Changchun, China
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28
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Rorsman P, Ashcroft FM. Pancreatic β-Cell Electrical Activity and Insulin Secretion: Of Mice and Men. Physiol Rev 2018; 98:117-214. [PMID: 29212789 PMCID: PMC5866358 DOI: 10.1152/physrev.00008.2017] [Citation(s) in RCA: 421] [Impact Index Per Article: 70.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Revised: 05/30/2017] [Accepted: 06/18/2017] [Indexed: 12/14/2022] Open
Abstract
The pancreatic β-cell plays a key role in glucose homeostasis by secreting insulin, the only hormone capable of lowering the blood glucose concentration. Impaired insulin secretion results in the chronic hyperglycemia that characterizes type 2 diabetes (T2DM), which currently afflicts >450 million people worldwide. The healthy β-cell acts as a glucose sensor matching its output to the circulating glucose concentration. It does so via metabolically induced changes in electrical activity, which culminate in an increase in the cytoplasmic Ca2+ concentration and initiation of Ca2+-dependent exocytosis of insulin-containing secretory granules. Here, we review recent advances in our understanding of the β-cell transcriptome, electrical activity, and insulin exocytosis. We highlight salient differences between mouse and human β-cells, provide models of how the different ion channels contribute to their electrical activity and insulin secretion, and conclude by discussing how these processes become perturbed in T2DM.
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Affiliation(s)
- Patrik Rorsman
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, United Kingdom; Department of Neuroscience and Physiology, Metabolic Research Unit, Göteborg, Sweden; and Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Frances M Ashcroft
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, United Kingdom; Department of Neuroscience and Physiology, Metabolic Research Unit, Göteborg, Sweden; and Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
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29
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Kyohara M, Shirakawa J, Okuyama T, Kimura A, Togashi Y, Tajima K, Hirano H, Terauchi Y. Serum Quantitative Proteomic Analysis Reveals Soluble EGFR To Be a Marker of Insulin Resistance in Male Mice and Humans. Endocrinology 2017; 158:4152-4164. [PMID: 29028997 DOI: 10.1210/en.2017-00339] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Accepted: 09/29/2017] [Indexed: 12/22/2022]
Abstract
To identify circulating factors as candidates involved in type 2 diabetes mellitus (T2DM), we conducted two different quantitative proteomic analyses: (1) db/db mouse sera were compared with db/+ mouse sera obtained at 4, 8, 12, and 24 weeks of age, and (2) db/db mouse sera from animals treated with liraglutide were compared with sera from animals without liraglutide treatment. Twenty proteins were differentially expressed in db/db mouse sera in the first experiment and eight proteins were differentially expressed in db/db mouse sera after liraglutide treatment in the second experiment. Soluble epidermal growth factor receptor (sEGFR) was identified as a common factor, and its protein level was significantly affected in both experiments. An enzyme-linked immunosorbent assay confirmed that the relatively low serum sEGFR levels in db/db mice were restored by liraglutide treatment. The serum sEGFR levels were elevated in diabetic mice with impaired insulin secretion and decreased in high-fat diet-fed mice and ob/ob mice. The serum sEGFR levels increased after the administration of a dual inhibitor of IGF-1/insulin receptor or streptozotocin. In humans with normal glucose tolerance or T2DM, the serum sEGFR levels were correlated with the fasting blood glucose, fasting serum insulin, homeostatic model assessment of insulin resistance, HbA1c, total cholesterol, low-density lipoprotein cholesterol, and triglycerides levels. These findings suggest that sEGFR might be a biomarker for evaluating insulin resistance or a therapeutic target of liraglutide.
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Affiliation(s)
- Mayu Kyohara
- Department of Endocrinology and Metabolism, Graduate School of Medicine, Yokohama City University, Japan
| | - Jun Shirakawa
- Department of Endocrinology and Metabolism, Graduate School of Medicine, Yokohama City University, Japan
| | - Tomoko Okuyama
- Department of Endocrinology and Metabolism, Graduate School of Medicine, Yokohama City University, Japan
| | - Ayuko Kimura
- Advanced Medical Research Center, Yokohama City University, Japan
| | - Yu Togashi
- Department of Endocrinology and Metabolism, Graduate School of Medicine, Yokohama City University, Japan
| | - Kazuki Tajima
- Department of Endocrinology and Metabolism, Graduate School of Medicine, Yokohama City University, Japan
| | - Hisashi Hirano
- Advanced Medical Research Center, Yokohama City University, Japan
| | - Yasuo Terauchi
- Department of Endocrinology and Metabolism, Graduate School of Medicine, Yokohama City University, Japan
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Abstract
Glucokinase (GK), the hexokinase involved in glucosensing in pancreatic β-cells, is also expressed in arcuate nucleus (AN) neurons and hypothalamic tanycytes, the cells that surround the basal third ventricle (3V). Several lines of evidence suggest that tanycytes may be involved in the regulation of energy homeostasis. Tanycytes have extended cell processes that contact the feeding-regulating neurons in the AN, particularly, agouti-related protein (AgRP), neuropeptide Y (NPY), cocaine- and amphetamine-regulated transcript (CART) and proopiomelanocortin (POMC) neurons. In this study, we developed an adenovirus expressing GK shRNA to inhibit GK expression in vivo. When injected into the 3V of rats, this adenovirus preferentially transduced tanycytes. qRT-PCR and Western blot assays confirmed GK mRNA and protein levels were lower in GK knockdown animals compared to the controls. In response to an intracerebroventricular glucose injection, the mRNA levels of anorexigenic POMC and CART and orexigenic AgRP and NPY neuropeptides were altered in GK knockdown animals. Similarly, food intake, meal duration, frequency of eating events and the cumulative eating time were increased, whereas the intervals between meals were decreased in GK knockdown rats, suggesting a decrease in satiety. Thus, GK expression in the ventricular cells appears to play an important role in feeding behavior.
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Shaheen A, Aljebali AMA. A hypothetical model to solve the controversy over the involvement of UCP2 in palmitate-induced β-cell dysfunction. Endocrine 2016; 54:276-283. [PMID: 27491555 DOI: 10.1007/s12020-016-1051-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Accepted: 07/04/2016] [Indexed: 11/24/2022]
Abstract
The aim of this article is to solve an existing controversy over the involvement of uncoupling protein-2 in the impairment of glucose-stimulated insulin secretion induced by chronic exposure of β-cells to palmitate. We analyzed and compared the results of studies that support and that deny the involvement of uncoupling protein-2 in this impairment. We observed that this impairment could occur in multiple stages. We provide a model in which palmitate-induced impairment of glucose-stimulated insulin secretion is proposed to occur in two stages, early stage and late stage, depending on the integrity of electron supply (glycolysis and Krebs cycle) and transport system through electron transport chain after palmitate treatment. Prolonged exposure of β-cells to palmitate can impair this system. Early-stage impairment occurs due to uncoupling by uncoupling protein-2 when this system is still intact. When this system becomes impaired, late-stage impairment occurs mainly due to reduced glucose-stimulated adenosine triphosphate production independent of uncoupling by uncoupling protein-2. The change in glucose-stimulated oxygen uptake after palmitate treatment reflects the integrity of this system and can be used to differentiate between the two stages. Some β-cells lines and islets appear to be more resistant to palmitate-induced impairment of electron supply and transport system than others, and therefore early stage is prominent in the more resistant cell lines and less prominent or absent in the less resistant cell lines. This may help to resolve the pathogenesis of diabetes and to monitor the progression of palmitate-induced β-cell dysfunction.
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Affiliation(s)
- Alaa Shaheen
- Kafr El-Sharakwa Medical Center, Kafr El-Sharakwa, Aga, Dakahlia, Egypt.
| | - Ahmad M A Aljebali
- Department of Zoology, Faculty of Science, Omar Al Mukhtar University, Bayda, Libya
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32
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Koppe L, Nyam E, Vivot K, Manning Fox JE, Dai XQ, Nguyen BN, Trudel D, Attané C, Moullé VS, MacDonald PE, Ghislain J, Poitout V. Urea impairs β cell glycolysis and insulin secretion in chronic kidney disease. J Clin Invest 2016; 126:3598-612. [PMID: 27525435 DOI: 10.1172/jci86181] [Citation(s) in RCA: 87] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 06/24/2016] [Indexed: 12/25/2022] Open
Abstract
Disorders of glucose homeostasis are common in chronic kidney disease (CKD) and are associated with increased mortality, but the mechanisms of impaired insulin secretion in this disease remain unclear. Here, we tested the hypothesis that defective insulin secretion in CKD is caused by a direct effect of urea on pancreatic β cells. In a murine model in which CKD is induced by 5/6 nephrectomy (CKD mice), we observed defects in glucose-stimulated insulin secretion in vivo and in isolated islets. Similarly, insulin secretion was impaired in normal mouse and human islets that were cultured with disease-relevant concentrations of urea and in islets from normal mice treated orally with urea for 3 weeks. In CKD mouse islets as well as urea-exposed normal islets, we observed an increase in oxidative stress and protein O-GlcNAcylation. Protein O-GlcNAcylation was also observed in pancreatic sections from CKD patients. Impairment of insulin secretion in both CKD mouse and urea-exposed islets was associated with reduced glucose utilization and activity of phosphofructokinase 1 (PFK-1), which could be reversed by inhibiting O-GlcNAcylation. Inhibition of O-GlcNAcylation also restored insulin secretion in both mouse models. These results suggest that insulin secretory defects associated with CKD arise from elevated circulating levels of urea that increase islet protein O-GlcNAcylation and impair glycolysis.
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Lakshmipathi J, Alvarez-Perez JC, Rosselot C, Casinelli GP, Stamateris RE, Rausell-Palamos F, O'Donnell CP, Vasavada RC, Scott DK, Alonso LC, Garcia-Ocaña A. PKCζ Is Essential for Pancreatic β-Cell Replication During Insulin Resistance by Regulating mTOR and Cyclin-D2. Diabetes 2016; 65:1283-96. [PMID: 26868297 PMCID: PMC4839210 DOI: 10.2337/db15-1398] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Accepted: 02/06/2016] [Indexed: 12/23/2022]
Abstract
Adaptive β-cell replication occurs in response to increased metabolic demand during insulin resistance. The intracellular mediators of this compensatory response are poorly defined and their identification could provide significant targets for β-cell regeneration therapies. Here we show that glucose and insulin in vitro and insulin resistance in vivo activate protein kinase C ζ (PKCζ) in pancreatic islets and β-cells. PKCζ is required for glucose- and glucokinase activator-induced proliferation of rodent and human β-cells in vitro. Furthermore, either kinase-dead PKCζ expression (KD-PKCζ) or disruption of PKCζ in mouse β-cells blocks compensatory β-cell replication when acute hyperglycemia/hyperinsulinemia is induced. Importantly, KD-PKCζ inhibits insulin resistance-mediated mammalian target of rapamycin (mTOR) activation and cyclin-D2 upregulation independent of Akt activation. In summary, PKCζ activation is key for early compensatory β-cell replication in insulin resistance by regulating the downstream signals mTOR and cyclin-D2. This suggests that alterations in PKCζ expression or activity might contribute to inadequate β-cell mass expansion and β-cell failure leading to type 2 diabetes.
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Affiliation(s)
- Jayalakshmi Lakshmipathi
- Diabetes, Obesity and Metabolism Institute, Division of Endocrinology, Diabetes and Bone Diseases, The Mindich Child Health and Development Institute, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Juan Carlos Alvarez-Perez
- Diabetes, Obesity and Metabolism Institute, Division of Endocrinology, Diabetes and Bone Diseases, The Mindich Child Health and Development Institute, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Carolina Rosselot
- Diabetes, Obesity and Metabolism Institute, Division of Endocrinology, Diabetes and Bone Diseases, The Mindich Child Health and Development Institute, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Gabriella P Casinelli
- Division of Pediatric Hematology/Oncology and Blood and Marrow Transplantation, Department of Pediatrics, Children's Hospital of Pittsburgh, Pittsburgh, PA
| | - Rachel E Stamateris
- Department of Medicine, University of Massachusetts Medical School, Worcester, MA
| | - Francisco Rausell-Palamos
- Diabetes, Obesity and Metabolism Institute, Division of Endocrinology, Diabetes and Bone Diseases, The Mindich Child Health and Development Institute, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Christopher P O'Donnell
- Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine, University of Pittsburgh, Pittsburgh, PA
| | - Rupangi C Vasavada
- Diabetes, Obesity and Metabolism Institute, Division of Endocrinology, Diabetes and Bone Diseases, The Mindich Child Health and Development Institute, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Donald K Scott
- Diabetes, Obesity and Metabolism Institute, Division of Endocrinology, Diabetes and Bone Diseases, The Mindich Child Health and Development Institute, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Laura C Alonso
- Department of Medicine, University of Massachusetts Medical School, Worcester, MA
| | - Adolfo Garcia-Ocaña
- Diabetes, Obesity and Metabolism Institute, Division of Endocrinology, Diabetes and Bone Diseases, The Mindich Child Health and Development Institute, Icahn School of Medicine at Mount Sinai, New York, NY
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Song Z, Wang H, Zhu L, Han M, Gao Y, Du Y, Wen Y. Curcumin improves high glucose-induced INS-1 cell insulin resistance via activation of insulin signaling. Food Funct 2016; 6:461-9. [PMID: 25474544 DOI: 10.1039/c4fo00608a] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Curcumin is a yellow pigment isolated from Corcuma longan. This research investigates the improvement of curcumin on INS-1 cells with insulin resistance induced by high glucose. INS-1 cells were treated with high glucose (30 mmol L(-1)) for 48 h. Subsequently, the medium was replaced with curcumin for 24 h. Curcumin effectively increased insulin gene expression and glucose stimulated insulin secretion (GSIS) in a dose-dependent manner. Furthermore, the molecular mechanism of curcumin-induced insulin expression and secretion in high glucose-induced INS-1 cells was investigated in this study. Curcumin increased the expression of glucose transporter 2 (GLUT2) and phosphorylation of insulin receptor (IR), insulin receptor substrate-1 (IRS1), phosphatidylinositol-3-kinase (PI3K) and AKT in the INS-1 cells. Moreover, curcumin stimulation increased the expression of PDX-1 and GCK. This investigation suggests that curcumin prevented high glucose-reduced insulin expression and secretion through activation of the PI3K/Akt/GLUT2 pathway in INS-1 cells.
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Affiliation(s)
- Zhenfeng Song
- Department of Nutrition and Food Hygiene, School of Public Health, Harbin Medical University, 157 Baojian Road, Nangang District, 150086, Harbin, People's Republic of China.
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35
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Althari S, Gloyn AL. When is it MODY? Challenges in the Interpretation of Sequence Variants in MODY Genes. Rev Diabet Stud 2016; 12:330-48. [PMID: 27111119 DOI: 10.1900/rds.2015.12.330] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
The genomics revolution has raised more questions than it has provided answers. Big data from large population-scale resequencing studies are increasingly deconstructing classic notions of Mendelian disease genetics, which support a simplistic correlation between mutational severity and phenotypic outcome. The boundaries are being blurred as the body of evidence showing monogenic disease-causing alleles in healthy genomes, and in the genomes of individu-als with increased common complex disease risk, continues to grow. In this review, we focus on the newly emerging challenges which pertain to the interpretation of sequence variants in genes implicated in the pathogenesis of maturity-onset diabetes of the young (MODY), a presumed mono-genic form of diabetes characterized by Mendelian inheritance. These challenges highlight the complexities surrounding the assignments of pathogenicity, in particular to rare protein-alerting variants, and bring to the forefront some profound clinical diagnostic implications. As MODY is both genetically and clinically heterogeneous, an accurate molecular diagnosis and cautious extrapolation of sequence data are critical to effective disease management and treatment. The biological and translational value of sequence information can only be attained by adopting a multitude of confirmatory analyses, which interrogate variant implication in disease from every possible angle. Indeed, studies which have effectively detected rare damaging variants in known MODY genes in normoglycemic individuals question the existence of a sin-gle gene mutation scenario: does monogenic diabetes exist when the genetic culprits of MODY have been systematical-ly identified in individuals without MODY?
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Affiliation(s)
- Sara Althari
- Oxford Centre for Diabetes Endocrinology and Metabolism, University of Oxford, UK
| | - Anna L Gloyn
- Oxford Centre for Diabetes Endocrinology and Metabolism, University of Oxford, UK
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36
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Shirakawa J, Okuyama T, Kyohara M, Yoshida E, Togashi Y, Tajima K, Yamazaki S, Kaji M, Koganei M, Sasaki H, Terauchi Y. DPP-4 inhibition improves early mortality, β cell function, and adipose tissue inflammation in db/db mice fed a diet containing sucrose and linoleic acid. Diabetol Metab Syndr 2016; 8:16. [PMID: 26937254 PMCID: PMC4774120 DOI: 10.1186/s13098-016-0138-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Accepted: 02/17/2016] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Diabetes therapy that not only lowers glucose levels but also lengthens life spans is required. We previously demonstrated that DPP-4 inhibition ameliorated β cell apoptosis and adipose tissue inflammation in β cell-specific glucokinase haploinsufficient mice fed a diet containing a combination of sucrose and linoleic acid (SL). METHODS In this study, we investigated the effects of DPP-4 inhibition in obese diabetic db/db mice fed an SL diet or a control diet containing sucrose and oleic acid (SO). We also examined the effects of DPP-4 inhibition in IRS-1-deficient mice fed an SL or SO diet as a model of insulin resistance. RESULTS DPP-4 inhibition efficiently increases the active GLP-1 levels in db/db mice. Unexpectedly, the SL diet, but not the SO diet, markedly increases mortality in the db/db mice. DPP-4 inhibition reduces the early lethality in SL-fed db/db mice. DPP-4 inhibition improves glucose tolerance, β cell function, and adipose tissue inflammation in db/db mice fed either diet. No significant changes in glycemic control or β cell mass were observed in any of the IRS-1-deficient mouse groups. CONCLUSIONS A diet containing a combination of sucrose and linoleic acid causes early lethality in obese diabetic db/db mice, but not in lean and insulin resistant IRS-1 knockout mice. DPP-4 inhibition has protective effects against the diet-induced lethality in db/db mice.
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Affiliation(s)
- Jun Shirakawa
- />Department of Endocrinology and Metabolism, Graduate School of Medicine, Yokohama-City University, 3-9 Fukuura, Kanazawa-ku, Yokohama, 236-0004 Japan
| | - Tomoko Okuyama
- />Department of Endocrinology and Metabolism, Graduate School of Medicine, Yokohama-City University, 3-9 Fukuura, Kanazawa-ku, Yokohama, 236-0004 Japan
| | - Mayu Kyohara
- />Department of Endocrinology and Metabolism, Graduate School of Medicine, Yokohama-City University, 3-9 Fukuura, Kanazawa-ku, Yokohama, 236-0004 Japan
| | - Eiko Yoshida
- />Department of Endocrinology and Metabolism, Graduate School of Medicine, Yokohama-City University, 3-9 Fukuura, Kanazawa-ku, Yokohama, 236-0004 Japan
| | - Yu Togashi
- />Department of Endocrinology and Metabolism, Graduate School of Medicine, Yokohama-City University, 3-9 Fukuura, Kanazawa-ku, Yokohama, 236-0004 Japan
| | - Kazuki Tajima
- />Department of Endocrinology and Metabolism, Graduate School of Medicine, Yokohama-City University, 3-9 Fukuura, Kanazawa-ku, Yokohama, 236-0004 Japan
| | - Shunsuke Yamazaki
- />Department of Endocrinology and Metabolism, Graduate School of Medicine, Yokohama-City University, 3-9 Fukuura, Kanazawa-ku, Yokohama, 236-0004 Japan
| | - Mitsuyo Kaji
- />Department of Endocrinology and Metabolism, Graduate School of Medicine, Yokohama-City University, 3-9 Fukuura, Kanazawa-ku, Yokohama, 236-0004 Japan
| | - Megumi Koganei
- />Food Science Research Laboratories, R&D Division, Meiji Co., Ltd., Odawara, Japan
| | - Hajime Sasaki
- />Food Science Research Laboratories, R&D Division, Meiji Co., Ltd., Odawara, Japan
- />Department of Nutritional and Life Sciences, Kanagawa Institute of Technology, Atsugi, Japan
| | - Yasuo Terauchi
- />Department of Endocrinology and Metabolism, Graduate School of Medicine, Yokohama-City University, 3-9 Fukuura, Kanazawa-ku, Yokohama, 236-0004 Japan
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37
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Roma LP, Duprez J, Jonas JC. Glucokinase activation is beneficial or toxic to cultured rat pancreatic islets depending on the prevailing glucose concentration. Am J Physiol Endocrinol Metab 2015; 309:E632-9. [PMID: 26264555 DOI: 10.1152/ajpendo.00154.2015] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Accepted: 08/10/2015] [Indexed: 11/22/2022]
Abstract
In rat pancreatic islets, β-cell gene expression, survival, and subsequent acute glucose stimulation of insulin secretion (GSIS) are optimally preserved by prolonged culture at 10 mM glucose (G10) and markedly altered by culture at G5 or G30. Here, we tested whether pharmacological glucokinase (GK) activation prevents these alterations during culture or improves GSIS after culture. Rat pancreatic islets were cultured 1-7 days at G5, G10, or G30 with or without 3 μM of the GK activator Ro 28-0450 (Ro). After culture, β-cell apoptosis and islet gene mRNA levels were measured, and the acute glucose-induced increase in NAD(P)H autofluorescence, intracellular calcium concentration, and insulin secretion were tested in the absence or presence of Ro. Prolonged culture of rat islets at G5 or G30 instead of G10 triggered β-cell apoptosis and reduced their glucose responsiveness. Addition of Ro during culture differently affected β-cell survival and glucose responsiveness depending on the glucose concentration during culture: it was beneficial to β-cell survival and function at G5, detrimental at G10, and ineffective at G30. In contrast, acute GK activation with Ro increased the glucose sensitivity of islets cultured at G10 but failed at restoring β-cell glucose responsiveness after culture at G5 or G30. We conclude that pharmacological GK activation prevents the alteration of β-cell survival and function by long-term culture at G5 but mimics glucotoxicity when added to G10. The complex effects of glucose on the β-cell phenotype result from changes in glucose metabolism and not from an effect of glucose per se.
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Affiliation(s)
- Leticia P Roma
- Université catholique de Louvain, Institut de recherche expérimentale et clinique, Pôle d'endocrinologie, diabète et nutrition, Brussels, Belgium; and
| | - Jessica Duprez
- Université catholique de Louvain, Institut de recherche expérimentale et clinique, Pôle d'endocrinologie, diabète et nutrition, Brussels, Belgium; and
| | - Jean-Christophe Jonas
- Université catholique de Louvain, Institut de recherche expérimentale et clinique, Pôle d'endocrinologie, diabète et nutrition, Brussels, Belgium; and Fonds de la recherche scientifique-FNRS, Brussels, Belgium
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38
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Loss of fibroblast growth factor 21 action induces insulin resistance, pancreatic islet hyperplasia and dysfunction in mice. Cell Death Dis 2015; 6:e1707. [PMID: 25811804 PMCID: PMC4385948 DOI: 10.1038/cddis.2015.80] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Revised: 02/16/2015] [Accepted: 02/17/2015] [Indexed: 01/16/2023]
Abstract
Fibroblast growth factor (FGF) 21 is an endocrine factor that normalizes glucose homeostasis and reduces insulin resistance in diabetes. Although the pancreas is an FGF21 target organ, its role in pancreatic islets remains obscure. This study aimed to elucidate the physiological role of FGF21 in pancreatic islets using FGF21-knockout (FGF21-KO) mice. Twenty-four-week-old male global FGF21-KO mice were used in this study. Glucose and insulin tolerance were assessed. Expression of genes and proteins related to islet function and underlying mechanisms were also examined. Islet morphology and insulin-secreting capacity were further evaluated. FGF21-KO mice exhibited insulin resistance while being normoglycemic, associated with increases in beta-cell proliferation and insulin synthesis, acting as compensatory responses. This phenotype probably results from enhanced growth hormone (GH) sensitivity in FGF21-KO mouse islets. In addition, ex vivo FGF21 treatment in normal C57BL/6J mouse islets reduced GH signaling, probably via upregulation of peroxisome proliferator-activated receptor gamma (PPARγ) and cytokine-inducible SH-2 containing (CIS) protein, whereas KO mouse islets displayed reduced PPARγ and CIS expression. FGF21 treatment also reversed GH-induced insulin expression, beta-cell proliferation and GH-impaired glucose-stimulated insulin secretion (GSIS) in islets. Furthermore, distorted islet morphology and impaired GSIS were observed in KO mice, suggestive of islet dysfunction, whereas the enhanced insulin expression and impaired GSIS in FGF21-KO mouse islets could be reversed by blockade of GH signaling. Our data indicate that FGF21 is important in the regulation of beta-cell proliferation and insulin synthesis, probably via modulation of GH signaling. These findings provide evidence that FGF21 is an obligatory metabolic regulator in pancreatic islets and shed new light onto the role of endogenous FGF21 in the pathogenesis of insulin resistance and islet dysfunction.
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Saito M, Kaneda A, Sugiyama T, Iida R, Otokuni K, Kaburagi M, Matsuoka H. Production of a mouse strain with impaired glucose tolerance by systemic heterozygous knockout of the glucokinase gene and its feasibility as a prediabetes model. Exp Anim 2015; 64:231-9. [PMID: 25765873 PMCID: PMC4547996 DOI: 10.1538/expanim.14-0089] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Exon II of glucokinase (Gk) was deleted to produce a systemic
heterozygous Gk knockout (Gk+/−) mouse. The
relative expression levels of Gk in the heart, lung, liver, stomach, and
pancreas in Gk+/− mice ranged from 0.41–0.68 versus that in
wild (Gk+/+) mice. On the other hand, its expression levels in
the brain, adipose tissue, and muscle ranged from 0.95–1.03, and its expression levels in
the spleen and kidney were nearly zero. Gk knockout caused no remarkable
off-target effect on the expression of 7 diabetes causing genes (Shp,
Hnf1a, Hnf1b, Irs1,
Irs2, Kir6.2, and Pdx1) in 10 organs.
The glucose tolerance test was conducted to determine the blood glucose concentrations
just after fasting for 24 h (FBG) and at 2 h after high-glucose application (GTT2h). The
FBG-GTT2h plots obtained with the wild strain fed the control diet (CD),
Gk+/− strain fed the CD, and
Gk+/− strain fed the HFD were distributed in separate areas
in the FBG-GTT2h diagram. The respective areas could be defined as the normal state,
prediabetes state, and diabetes state, respectively. Based on the results, the criteria
for prediabetes could be defined for the Gk+/− strain
developed in this study.
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Affiliation(s)
- Mikako Saito
- Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588, Japan
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40
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Xu P, Ye X, Zhang Y, Yuan Q, Liu M, Wu Q, Ren G, Li D. Long-acting hypoglycemic effects of PEGylated FGF21 and insulin glargine in mice with type 1 diabetes. J Diabetes Complications 2015; 29:5-12. [PMID: 25456819 DOI: 10.1016/j.jdiacomp.2014.10.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2014] [Revised: 09/27/2014] [Accepted: 10/02/2014] [Indexed: 01/10/2023]
Abstract
OBJECTIVE In this study, we compared the long-acting hypoglycemic effect of PEGylated FGF21 (PEG-FGF21) with insulin glargine in mice with STZ-induced type 1 diabetes. METHODS PEG-FGF21 and insulin glargine were administered once daily for two months, and blood glucose was measured prior to the next administration. Real-time PCR was used to measure mRNA expression of glucokinase (GK), glucose 6-phosphatase (G6pase), phosphoenolpyruvate carboxykinase (PEPCK), glucose transporter 1 (GLUT1) and glucose transporter 4 (GLUT4). RESULTS During long-term treatment, the blood glucose of untreated mice remained at 25.0 to 28.0mmol/L for the whole experiment, and the blood glucose of mice treated with insulin glargine remained at 16.5 to 18.0mmol/L. However, mice treated with PEG-FGF21 had lower blood glucose levels of 8.0 to 9.0mmol/L on day 10 and maintained this level until the end of the experiment. qRT-PCR showed that PEG-FGF21 up-regulated mRNA expression of GK and GLUT1, and down-regulated mRNA expression of G6Pase and PEPCK. Insulin glargine up-regulated mRNA expression of GLUT4, but had no effect on GK, G6Pase, PEPCK or GLUT1. CONCLUSIONS PEG-FGF21 has a better long-acting efficacy than insulin glargine. PEG-FGF21 achieves glucose clearance by accelerating glycolysis by up-regulating expression of GK and GLUT1 and inhibiting gluconeogenesis via down-regulation of G6Pase and PEPCK expression.
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Affiliation(s)
- Pengfei Xu
- Biopharmaceutical Lab, College of Life Science, Northeast Agricultural University, Harbin, China
| | - Xianlong Ye
- Biopharmaceutical Lab, College of Life Science, Northeast Agricultural University, Harbin, China
| | - Yingjie Zhang
- Biopharmaceutical Lab, College of Life Science, Northeast Agricultural University, Harbin, China
| | - Qingyan Yuan
- Biopharmaceutical Lab, College of Life Science, Northeast Agricultural University, Harbin, China
| | - Mingyao Liu
- Biopharmaceutical Lab, College of Life Science, Northeast Agricultural University, Harbin, China
| | - Qiang Wu
- Biopharmaceutical Lab, College of Life Science, Northeast Agricultural University, Harbin, China
| | - Guiping Ren
- Biopharmaceutical Lab, College of Life Science, Northeast Agricultural University, Harbin, China.
| | - Deshan Li
- Biopharmaceutical Lab, College of Life Science, Northeast Agricultural University, Harbin, China; Key Laboratory of Agricultural Biological Functional Gene, Northeast Agricultural University, Harbin, P.R. China.
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Piccand J, Strasser P, Hodson DJ, Meunier A, Ye T, Keime C, Birling MC, Rutter GA, Gradwohl G. Rfx6 maintains the functional identity of adult pancreatic β cells. Cell Rep 2014; 9:2219-32. [PMID: 25497096 PMCID: PMC4542305 DOI: 10.1016/j.celrep.2014.11.033] [Citation(s) in RCA: 90] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Revised: 10/27/2014] [Accepted: 11/20/2014] [Indexed: 01/09/2023] Open
Abstract
Increasing evidence suggests that loss of β cell characteristics may cause insulin secretory deficiency in diabetes, but the underlying mechanisms remain unclear. Here, we show that Rfx6, whose mutation leads to neonatal diabetes in humans, is essential to maintain key features of functionally mature β cells in mice. Rfx6 loss in adult β cells leads to glucose intolerance, impaired β cell glucose sensing, and defective insulin secretion. This is associated with reduced expression of core components of the insulin secretion pathway, including glucokinase, the Abcc8/SUR1 subunit of KATP channels and voltage-gated Ca(2+) channels, which are direct targets of Rfx6. Moreover, Rfx6 contributes to the silencing of the vast majority of "disallowed" genes, a group usually specifically repressed in adult β cells, and thus to the maintenance of β cell maturity. These findings raise the possibility that changes in Rfx6 expression or activity may contribute to β cell failure in humans.
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Affiliation(s)
- Julie Piccand
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Institut National de la Santé et de la Recherche Médicale U964, Centre National de Recherche Scientifique UMR7104, Université de Strasbourg, Illkirch 67404, France
| | - Perrine Strasser
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Institut National de la Santé et de la Recherche Médicale U964, Centre National de Recherche Scientifique UMR7104, Université de Strasbourg, Illkirch 67404, France
| | - David J Hodson
- Section of Cell Biology, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Imperial College London, Hammersmith Hospital, du Cane Road, London W12 0NN, UK
| | - Aline Meunier
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Institut National de la Santé et de la Recherche Médicale U964, Centre National de Recherche Scientifique UMR7104, Université de Strasbourg, Illkirch 67404, France
| | - Tao Ye
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Institut National de la Santé et de la Recherche Médicale U964, Centre National de Recherche Scientifique UMR7104, Université de Strasbourg, Illkirch 67404, France
| | - Céline Keime
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Institut National de la Santé et de la Recherche Médicale U964, Centre National de Recherche Scientifique UMR7104, Université de Strasbourg, Illkirch 67404, France
| | | | - Guy A Rutter
- Section of Cell Biology, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Imperial College London, Hammersmith Hospital, du Cane Road, London W12 0NN, UK
| | - Gérard Gradwohl
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, Institut National de la Santé et de la Recherche Médicale U964, Centre National de Recherche Scientifique UMR7104, Université de Strasbourg, Illkirch 67404, France.
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42
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Baker DJ, Atkinson AM, Wilkinson GP, Coope GJ, Charles AD, Leighton B. Characterization of the heterozygous glucokinase knockout mouse as a translational disease model for glucose control in type 2 diabetes. Br J Pharmacol 2014; 171:1629-41. [PMID: 24772483 DOI: 10.1111/bph.12498] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND AND PURPOSE The global heterozygous glucokinase (GK) knockout (gk(wt/del)) male mouse, fed on a high-fat (60% by energy) diet, has provided a robust and reproducible model of hyperglycaemia. This model could be highly relevant to some facets of human type 2 diabetes (T2D). We aimed to investigate the ability of standard therapeutic agents to lower blood glucose at translational doses, and to explore the glucose-lowering potential of novel glucokinase activators (GKAs) in this model. EXPERIMENTAL APPROACH We measured the ability of insulin, metformin, glipizide, exendin-4 and sitagliptin, after acute or repeat dose administration, to lower free-feeding glucose levels in gk(wt/del) mice. Further, we measured the ability of novel GKAs, GKA23, GKA71 and AZD6370 to control glucose either alone or in combination with some standard agents. KEY RESULTS A single dose of insulin (1 unit·kg(-1)), metformin (150, 300 mg·kg(-1)), glipizide (0.1, 0.3 mg·kg(-1)), exendin-4 (2, 20 μg·kg(-1)) and GKAs reduced free-feeding glucose levels. Sitagliptin (10 mg·kg(-1)), metformin (300 mg·kg(-1)) and AZD6370 (30, 400 mg·kg(-1)) reduced glucose excursions on repeat dosing. At a supra-therapeutic dose (400 mg·kg(-1)), AZD6370 also lowered basal levels of glucose without inducing hypoglycaemia. CONCLUSION AND IMPLICATIONS Standard glucose-lowering therapeutic agents demonstrated significant acute glucose lowering in male gk(wt/del) mice at doses corresponding to therapeutic free drug levels in man, suggesting the potential of these mice as a translatable model of human T2D. Novel GKAs also lowered glucose in this mouse model.
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Nakamura A, Terauchi Y. Present status of clinical deployment of glucokinase activators. J Diabetes Investig 2014; 6:124-32. [PMID: 25802718 PMCID: PMC4364845 DOI: 10.1111/jdi.12294] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Revised: 09/24/2014] [Accepted: 09/25/2014] [Indexed: 12/14/2022] Open
Abstract
Glucokinase is one of four members of the hexokinase family of enzymes. Its expression is limited to the major organs (such as the pancreas, liver, brain and the gastrointestinal tract) that are thought to have an integrated role in glucose sensing. In the liver, phosphorylation of glucose by glucokinase promotes glycogen synthesis, whereas in the β-cells, it results in insulin release. Studies of glucokinase-linked genetically-modified mice and mutations in humans have illustrated the important roles played by glucokinase in whole-body glucose homeostasis, and suggest that the use of pharmacological agents that augment glucokinase activity could represent a viable treatment strategy in patients with type 2 diabetes. Since 2003, many glucokinase activators (GKAs) have been developed, and their ability to lower the blood glucose has been shown in several animal models of type 2 diabetes. Also, we and others have shown in mouse models that GKAs also have the effect of stimulating the proliferation of β-cells. However, the results of recent phase II trials have shown that GKAs lose their efficacy within several months of use, and that their use is associated with a high incidence of hypoglycemia; furthermore, patients treated with GKAs frequently developed dyslipidemia. A better understanding of the role of glucokinase in metabolic effects is required to resolve several issues identified in clinical trials.
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Affiliation(s)
- Akinobu Nakamura
- Division of Immunology and Metabolism, Hokkaido University Graduate School of Medicine Sapporo, Japan
| | - Yasuo Terauchi
- Department of Endocrinology and Metabolism, Graduate School of Medicine, Yokohama City University Yokohama, Japan
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Shirakawa J, Okuyama T, Yoshida E, Shimizu M, Horigome Y, Tuno T, Hayasaka M, Abe S, Fuse M, Togashi Y, Terauchi Y. Effects of the antitumor drug OSI-906, a dual inhibitor of IGF-1 receptor and insulin receptor, on the glycemic control, β-cell functions, and β-cell proliferation in male mice. Endocrinology 2014; 155:2102-11. [PMID: 24712877 DOI: 10.1210/en.2013-2032] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The IGF-1 receptor has become a therapeutic target for the treatment of cancer. The efficacy of OSI-906 (linstinib), a dual inhibitor of IGF-1 receptor and insulin receptor, for solid cancers has been examined in clinical trials. The effects of OSI-906, however, on the blood glucose levels and pancreatic β-cell functions have not yet been reported. We investigated the impact of OSI-906 on glycemic control, insulin secretion, β-cell mass, and β-cell proliferation in male mice. Oral administration of OSI-906 worsened glucose tolerance in a dose-dependent manner in the wild-type mice. OSI-906 at a dose equivalent to the clinical daily dose (7.5 mg/kg) transiently evoked glucose intolerance and hyperinsulinemia. Insulin receptor substrate (IRS)-2-deficient mice and mice with diet-induced obesity, both models of peripheral insulin resistance, exhibited more severe glucose intolerance after OSI-906 administration than glucokinase-haploinsufficient mice, a model of impaired insulin secretion. Phloridzin improved the hyperglycemia induced by OSI-906 in mice. In vitro, OSI-906 showed no effect on insulin secretion from isolated islets. After daily administration of OSI-906 for a week to mice, the β-cell mass and β-cell proliferation rate were significantly increased. The insulin signals in the β-cells were apparently unaffected in those mice. Taken together, the results suggest that OSI-906 could exacerbate diabetes, especially in patients with insulin resistance. On the other hand, the results suggest that the β-cell mass may expand in response to chemotherapy with this drug.
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Affiliation(s)
- Jun Shirakawa
- Department of Endocrinology and Metabolism, Graduate School of Medicine, Yokohama-City University, Yokohama 236-0004, Japan
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45
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Togashi Y, Shirakawa J, Orime K, Kaji M, Sakamoto E, Tajima K, Inoue H, Nakamura A, Tochino Y, Goshima Y, Shimomura I, Terauchi Y. β-Cell proliferation after a partial pancreatectomy is independent of IRS-2 in mice. Endocrinology 2014; 155:1643-52. [PMID: 24517226 DOI: 10.1210/en.2013-1796] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The glucokinase-induced up-regulation of insulin receptor substrate 2 (IRS-2) plays an important role in β-cell adaptive proliferation in response to high-fat diet-induced insulin resistance. This study aimed to investigate the role of IRS-2 in the proliferation of β-cells after a 60% partial pancreatectomy. IRS-2-deficient (IRS-2(-/-)) mice or wild-type mice were subjected to a pancreatectomy (60% partial pancreatectomy) or a sham operation (Sham). The β-cell proliferation and gene expression profiles of the islets were then assessed. Gene expression in islets from pancreatectomized and Sham C57BL/6J male mice was analyzed using a cDNA microarray analysis. To compare with β-cell proliferation induced by a high-fat diet, Gck(+/-) mice subjected to a pancreatectomy were also analyzed. The IRS-2(-/-) mice exhibited β-cell expansion and a significant increase in β-cell proliferation after the pancreatectomy, compared with the Sham group. Although glucose-stimulated insulin secretion from islets was not impaired, IRS-2(-/-) mice manifested severe hyperglycemia after the pancreatectomy. The expression levels of Aurora kinase B, Cyclin A, and Cyclin B1 in the pancreatectomized islets were also enhanced in the IRS-2(-/-) mice. A gene set enrichment analysis suggested an association between the genes that were up-regulated in the pancreatectomized islets and those involved in M phase progression in the cell cycle. β-Cell proliferation after a pancreatectomy was observed even in the Gck(+/-) mice. In conclusion, IRS-2 was not required for β-cell proliferation but might be needed for functional β-cell mass, after a pancreatectomy. A partial pancreatectomy in mice may be an attractive model for the development of new strategy for exploring the unique nature of β-cell proliferation.
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Affiliation(s)
- Yu Togashi
- Department of Endocrinology and Metabolism (Y.Tog., J.S., K.O., M.K., E.S., K.T., H.I., A.N., Y.Te.) and Molecular Pharmacology and Neurobiology (Y.G., J.S.), Graduate School of Medicine Yokohama-City University, Yokohama 236-0004, Japan; and Department of Metabolic Medicine (Y.Toc., I.S.), Graduate School of Osaka University, Osaka 565-0871, Japan
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Flanagan SE, De Franco E, Lango Allen H, Zerah M, Abdul-Rasoul MM, Edge JA, Stewart H, Alamiri E, Hussain K, Wallis S, de Vries L, Rubio-Cabezas O, Houghton JAL, Edghill EL, Patch AM, Ellard S, Hattersley AT. Analysis of transcription factors key for mouse pancreatic development establishes NKX2-2 and MNX1 mutations as causes of neonatal diabetes in man. Cell Metab 2014; 19:146-54. [PMID: 24411943 PMCID: PMC3887257 DOI: 10.1016/j.cmet.2013.11.021] [Citation(s) in RCA: 84] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2013] [Revised: 08/05/2013] [Accepted: 11/15/2013] [Indexed: 12/29/2022]
Abstract
Understanding transcriptional regulation of pancreatic development is required to advance current efforts in developing beta cell replacement therapies for patients with diabetes. Current knowledge of key transcriptional regulators has predominantly come from mouse studies, with rare, naturally occurring mutations establishing their relevance in man. This study used a combination of homozygosity analysis and Sanger sequencing in 37 consanguineous patients with permanent neonatal diabetes to search for homozygous mutations in 29 transcription factor genes important for murine pancreatic development. We identified homozygous mutations in 7 different genes in 11 unrelated patients and show that NKX2-2 and MNX1 are etiological genes for neonatal diabetes, thus confirming their key role in development of the human pancreas. The similar phenotype of the patients with recessive mutations and mice with inactivation of a transcription factor gene support there being common steps critical for pancreatic development and validate the use of rodent models for beta cell development.
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Affiliation(s)
- Sarah E Flanagan
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter EX2 5DW, UK
| | - Elisa De Franco
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter EX2 5DW, UK
| | - Hana Lango Allen
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter EX2 5DW, UK
| | - Michele Zerah
- Presbyterian Medical Group, Albuquerque, NM 87106, USA
| | | | - Julie A Edge
- Oxford Children's Hospital, Headington, Oxford OX3 9DU, UK
| | - Helen Stewart
- Department of Clinical Genetics, Oxford University Hospitals NHS Trust, Oxford OX3 7LE, UK
| | - Elham Alamiri
- Al Qassimi Hospital, Sharjah 3500, United Arab Emirates
| | - Khalid Hussain
- London Centre for Paediatric Endocrinology and Metabolism, Great Ormond Street Hospital for Children NHS Trust, and The Institute of Child Health, University College London, London WC1N 1EH, UK
| | - Sam Wallis
- Neonatal Unit, Bradford Royal Infirmary, Bradford BD9 6RJ, UK
| | - Liat de Vries
- Institute of Endocrinology and Diabetes, Schneider Children's Medical Center of Israel, PetahTikva, and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 49202, Israel
| | - Oscar Rubio-Cabezas
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter EX2 5DW, UK; Department of Paediatric Endocrinology, Hospital Infantil Niño Jesús, Madrid 28009, Spain
| | - Jayne A L Houghton
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter EX2 5DW, UK
| | - Emma L Edghill
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter EX2 5DW, UK
| | - Ann-Marie Patch
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter EX2 5DW, UK
| | - Sian Ellard
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter EX2 5DW, UK
| | - Andrew T Hattersley
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter EX2 5DW, UK.
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Schermerhorn T. Normal glucose metabolism in carnivores overlaps with diabetes pathology in non-carnivores. Front Endocrinol (Lausanne) 2013; 4:188. [PMID: 24348462 PMCID: PMC3847661 DOI: 10.3389/fendo.2013.00188] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2013] [Accepted: 11/19/2013] [Indexed: 12/15/2022] Open
Abstract
Carnivores, such as the dolphin and the domestic cat, have numerous adaptations that befit consumption of diets with high protein and fat content, with little carbohydrate content. Consequently, nutrient metabolism in carnivorous species differs substantially from that of non-carnivores. Important metabolic pathways known to differ between carnivores and non-carnivores are implicated in the development of diabetes and insulin resistance in non-carnivores: (1) the hepatic glucokinase (GCK) pathway is absent in healthy carnivores yet GCK deficiency may result in diabetes in rodents and humans, (2) healthy dolphins and cats are prone to periods of fasting hyperglycemia and exhibit insulin resistance, both of which are risk factors for diabetes in non-carnivores. Similarly, carnivores develop naturally occurring diseases such as hemochromatosis, fatty liver, obesity, and diabetes that have strong parallels with the same disorders in humans. Understanding how evolution, environment, diet, and domestication may play a role with nutrient metabolism in the dolphin and cat may also be relevant to human diabetes.
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Affiliation(s)
- Thomas Schermerhorn
- Department of Clinical Sciences, College of Veterinary Medicine, Kansas State University, Manhattan, KS, USA
- *Correspondence: Thomas Schermerhorn, Department of Clinical Sciences, College of Veterinary Medicine, Kansas State University, 1800 Denison Avenue, Manhattan, KS 66506-5606, USA e-mail:
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48
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Shirakawa J, Togashi Y, Sakamoto E, Kaji M, Tajima K, Orime K, Inoue H, Kubota N, Kadowaki T, Terauchi Y. Glucokinase activation ameliorates ER stress-induced apoptosis in pancreatic β-cells. Diabetes 2013; 62:3448-58. [PMID: 23801577 PMCID: PMC3781485 DOI: 10.2337/db13-0052] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The derangement of endoplasmic reticulum (ER) homeostasis triggers β-cell apoptosis, leading to diabetes. Glucokinase upregulates insulin receptor substrate 2 (IRS-2) expression in β-cells, but the role of glucokinase and IRS-2 in ER stress has been unclear. In this study, we investigated the impact of glucokinase activation by glucokinase activator (GKA) on ER stress in β-cells. GKA administration improved β-cell apoptosis in Akita mice, a model of ER stress-mediated diabetes. GKA increased the expression of IRS-2 in β-cells, even under ER stress. Both glucokinase-deficient Akita mice and IRS-2-deficient Akita mice exhibited an increase in β-cell apoptosis, compared with Akita mice. β-cell-specific IRS-2-overexpressing (βIRS-2-Tg) Akita mice showed less β-cell apoptosis than Akita mice. IRS-2-deficient islets were vulnerable, but βIRS-2-Tg islets were resistant to ER stress-induced apoptosis. Meanwhile, GKA regulated the expressions of C/EBP homologous protein (CHOP) and other ER stress-related genes in an IRS-2-independent fashion in islets. GKA suppressed the expressions of CHOP and Bcl2-associated X protein (Bax) and protected against β-cell apoptosis under ER stress in an ERK1/2-dependent, IRS-2-independent manner. Taken together, GKA ameliorated ER stress-mediated apoptosis by harmonizing IRS-2 upregulation and the IRS-2-independent control of apoptosis in β-cells.
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Affiliation(s)
- Jun Shirakawa
- Department of Endocrinology and Metabolism, Graduate School of Medicine, Yokohama City University, Yokohama, Japan
| | - Yu Togashi
- Department of Endocrinology and Metabolism, Graduate School of Medicine, Yokohama City University, Yokohama, Japan
| | - Eri Sakamoto
- Department of Endocrinology and Metabolism, Graduate School of Medicine, Yokohama City University, Yokohama, Japan
| | - Mitsuyo Kaji
- Department of Endocrinology and Metabolism, Graduate School of Medicine, Yokohama City University, Yokohama, Japan
| | - Kazuki Tajima
- Department of Endocrinology and Metabolism, Graduate School of Medicine, Yokohama City University, Yokohama, Japan
| | - Kazuki Orime
- Department of Endocrinology and Metabolism, Graduate School of Medicine, Yokohama City University, Yokohama, Japan
| | - Hideaki Inoue
- Department of Endocrinology and Metabolism, Graduate School of Medicine, Yokohama City University, Yokohama, Japan
| | - Naoto Kubota
- Department of Diabetes and Metabolic Diseases, Graduate School of Medicine, University of Tokyo, Tokyo, Japan
| | - Takashi Kadowaki
- Department of Diabetes and Metabolic Diseases, Graduate School of Medicine, University of Tokyo, Tokyo, Japan
| | - Yasuo Terauchi
- Department of Endocrinology and Metabolism, Graduate School of Medicine, Yokohama City University, Yokohama, Japan
- Corresponding author: Yasuo Terauchi,
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49
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Taylor BL, Liu FF, Sander M. Nkx6.1 is essential for maintaining the functional state of pancreatic beta cells. Cell Rep 2013; 4:1262-75. [PMID: 24035389 DOI: 10.1016/j.celrep.2013.08.010] [Citation(s) in RCA: 232] [Impact Index Per Article: 21.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2013] [Revised: 07/11/2013] [Accepted: 08/05/2013] [Indexed: 02/06/2023] Open
Abstract
Recently, loss of beta-cell-specific traits has been proposed as an early cause of beta cell failure in diabetes. However, the molecular mechanisms that underlie the loss of beta cell features remain unclear. Here, we identify an Nkx6.1-controlled gene regulatory network as essential for maintaining the functional and molecular traits of mature beta cells. Conditional Nkx6.1 inactivation in adult mice caused rapid-onset diabetes and hypoinsulinemia. Genome-wide analysis of Nkx6.1-regulated genes and functional assays further revealed a critical role for Nkx6.1 in the control of insulin biosynthesis, insulin secretion, and beta cell proliferation. Over time, Nkx6.1-deficient beta cells acquired molecular characteristics of delta cells, revealing a molecular link between impaired beta cell functional properties and loss of cell identity. Given that Nkx6.1 levels are reduced in human type 2 diabetic beta cells, our study lends support to the concept that loss of beta cell features could contribute to the pathogenesis of diabetes.
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Affiliation(s)
- Brandon L Taylor
- Departments of Pediatrics and Cellular and Molecular Medicine, Pediatric Diabetes Research Center, University of California, San Diego, La Jolla, CA 92093-0695, USA
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50
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Kuliawat R, Klein L, Gong Z, Nicoletta-Gentile M, Nemkal A, Cui L, Bastie C, Su K, Huffman D, Surana M, Barzilai N, Fleischer N, Muzumdar R. Potent humanin analog increases glucose-stimulated insulin secretion through enhanced metabolism in the β cell. FASEB J 2013; 27:4890-8. [PMID: 23995290 DOI: 10.1096/fj.13-231092] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Humanin (HN) is a 24-aa polypeptide that offers protection from Alzheimer's disease and myocardial infarction, increases insulin sensitivity, improves survival of β cells, and delays onset of diabetes. Here we examined the acute effects of HN on insulin secretion and potential mechanisms through which they are mediated. Effects of a potent HN analog, HNGF6A, on glucose-stimulated insulin secretion (GSIS) were assessed in vivo and in isolated pancreatic islets and cultured murine β cell line (βTC3) in vitro. Sprague-Dawley rats (3 mo old) that received HNGF6A required a significantly higher glucose infusion rate and demonstrated higher insulin levels during hyperglycemic clamps compared to saline controls. In vitro, compared to scrambled peptide controls, HNGF6A increased GSIS in isolated islets from both normal and diabetic mice as well as in βTC3 cells. Effects of HNGF6A on GSIS were dose dependent, K-ATP channel independent, and associated with enhanced glucose metabolism. These findings demonstrate that HNGF6A increases GSIS in whole animals, from isolated islets and from cells in culture, which suggests a direct effect on the β cell. The glucose-dependent effects on insulin secretion along with the established effects on insulin action suggest potential for HN and its analogs in the treatment of diabetes.
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Affiliation(s)
- Regina Kuliawat
- 2Department of Pediatrics, Golding Bldg. 705, Albert Einstein College of Medicine, 1300 Morris Park Ave., Bronx, NY 10461, USA.
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