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Sabadell-Basallote J, Astiarraga B, Castaño C, Ejarque M, Repollés-de-Dalmau M, Quesada I, Blanco J, Nuñez-Roa C, Rodríguez-Peña MM, Martínez L, De Jesus DF, Marroqui L, Bosch R, Montanya E, Sureda FX, Tura A, Mari A, Kulkarni RN, Vendrell J, Fernández-Veledo S. SUCNR1 regulates insulin secretion and glucose elevates the succinate response in people with prediabetes. J Clin Invest 2024; 134:e173214. [PMID: 38713514 PMCID: PMC11178533 DOI: 10.1172/jci173214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 04/26/2024] [Indexed: 05/09/2024] Open
Abstract
Pancreatic β-cell dysfunction is a key feature of type 2 diabetes, and novel regulators of insulin secretion are desirable. Here we report that the succinate receptor (SUCNR1) is expressed in β-cells and is up-regulated in hyperglycemic states in mice and humans. We found that succinate acts as a hormone-like metabolite and stimulates insulin secretion via a SUCNR1-Gq-PKC-dependent mechanism in human β-cells. Mice with β-cell-specific Sucnr1 deficiency exhibit impaired glucose tolerance and insulin secretion on a high-fat diet, indicating that SUCNR1 is essential for preserving insulin secretion in diet-induced insulin resistance. Patients with impaired glucose tolerance show an enhanced nutritional-related succinate response, which correlates with the potentiation of insulin secretion during intravenous glucose administration. These data demonstrate that the succinate/SUCNR1 axis is activated by high glucose and identify a GPCR-mediated amplifying pathway for insulin secretion relevant to the hyperinsulinemia of prediabetic states.
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Affiliation(s)
- Joan Sabadell-Basallote
- Unitat de Recerca, Hospital Universitari Joan XXIII, Insitut d'Investigació Sanitària Pere Virgili, Tarragona, Spain
| | - Brenno Astiarraga
- Unitat de Recerca, Hospital Universitari Joan XXIII, Insitut d'Investigació Sanitària Pere Virgili, Tarragona, Spain
| | - Carlos Castaño
- Unitat de Recerca, Hospital Universitari Joan XXIII, Institut d'Investigació Sanitària Pere Virgili, Tarragona, Spain
| | - Miriam Ejarque
- Unitat de Recerca, Hospital Universitari Joan XXIII, Insitut d'Investigació Sanitària Pere Virgili, Tarragona, Spain
| | - Maria Repollés-de-Dalmau
- Unitat de Recerca, Hospital Universitari Joan XXIII, Insitut d'Investigació Sanitària Pere Virgili, Tarragona, Spain
| | - Ivan Quesada
- CIBER de Diabetes y Enfermedades Metabólicas Asociadas, Instituto de Salud Carlos III, ELCHE, Spain
| | - Jordi Blanco
- Departament de Medicina i Cirurgia, Universitat Rovira i Virgili, Reus, Spain
| | - Catalina Nuñez-Roa
- Unitat de Recerca, Hospital Universitari Joan XXIII, Institut d'Investigació Sanitària Pere Virgili, Tarragona, Spain
| | - M-Mar Rodríguez-Peña
- Unitat de Recerca, Hospital Universitari Joan XXIII, Institut d'Investigació Sanitària Pere Virgili, Tarragona, Spain
| | - Laia Martínez
- Unitat de Recerca, Hospital Universitari Joan XXIII, Institut d'Investigació Sanitària Pere Virgili, Tarragona, Spain
| | - Dario F De Jesus
- Section of Islet Cell and Regenerative Biology, Joslin Diabetes Center, Boston, United States of America
| | - Laura Marroqui
- CIBER de Diabetes y Enfermedades Metabólicas Asociadas, Instituto de Salud Carlos III, ELCHE, Spain
| | - Ramon Bosch
- Unitat de Recerca, Hospital Universitari Joan XXIII, Insitut d'Investigació Sanitària Pere Virgili, Tarragona, Spain
| | - Eduard Montanya
- CIBER de Diabetes y Enfermedades Metabólicas Asociadas, Instituto de Salud Carlos III, ELCHE, Spain
| | - Francesc X Sureda
- Section of Islet Cell and Regenerative Biology, Joslin Diabetes Center, Boston, United States of America
| | - Andrea Tura
- Institute of Neuroscience, National Research Council, Padova, Italy
| | - Andrea Mari
- Institute of Neuroscience, National Research Council, Padova, Italy
| | - Rohit N Kulkarni
- Section of Islet Cell and Regenerative Biology, Joslin Diabetes Center, Boston, United States of America
| | - Joan Vendrell
- Unitat de Recerca, Hospital Universitari Joan XXIII, Institut d'Investigació Sanitària Pere Virgili, Tarragona, Spain
| | - Sonia Fernández-Veledo
- Unitat de Recerca, Hospital Universitari Joan XXIII, Institut d'Investigació Sanitària Pere Virgili, Tarragona, Spain
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Lee S, Xu H, Van Vleck A, Mawla AM, Li AM, Ye J, Huising MO, Annes JP. β-Cell Succinate Dehydrogenase Deficiency Triggers Metabolic Dysfunction and Insulinopenic Diabetes. Diabetes 2022; 71:1439-1453. [PMID: 35472723 PMCID: PMC9233299 DOI: 10.2337/db21-0834] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Accepted: 03/26/2022] [Indexed: 11/20/2022]
Abstract
Mitochondrial dysfunction plays a central role in type 2 diabetes (T2D); however, the pathogenic mechanisms in pancreatic β-cells are incompletely elucidated. Succinate dehydrogenase (SDH) is a key mitochondrial enzyme with dual functions in the tricarboxylic acid cycle and electron transport chain. Using samples from human with diabetes and a mouse model of β-cell-specific SDH ablation (SDHBβKO), we define SDH deficiency as a driver of mitochondrial dysfunction in β-cell failure and insulinopenic diabetes. β-Cell SDH deficiency impairs glucose-induced respiratory oxidative phosphorylation and mitochondrial membrane potential collapse, thereby compromising glucose-stimulated ATP production, insulin secretion, and β-cell growth. Mechanistically, metabolomic and transcriptomic studies reveal that the loss of SDH causes excess succinate accumulation, which inappropriately activates mammalian target of rapamycin (mTOR) complex 1-regulated metabolic anabolism, including increased SREBP-regulated lipid synthesis. These alterations, which mirror diabetes-associated human β-cell dysfunction, are partially reversed by acute mTOR inhibition with rapamycin. We propose SDH deficiency as a contributing mechanism to the progressive β-cell failure of diabetes and identify mTOR complex 1 inhibition as a potential mitigation strategy.
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Affiliation(s)
- Sooyeon Lee
- Division of Endocrinology, Department of Medicine, Stanford University, Stanford, CA
| | - Haixia Xu
- Division of Endocrinology, Department of Medicine, Stanford University, Stanford, CA
| | - Aidan Van Vleck
- Division of Endocrinology, Department of Medicine, Stanford University, Stanford, CA
| | - Alex M. Mawla
- Department of Neurobiology, Physiology and Behavior, College of Biological Sciences, University of California, Davis, Davis, CA
| | - Albert Mao Li
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA
- Cancer Biology Program, Stanford University School of Medicine, Stanford, CA
| | - Jiangbin Ye
- Department of Radiation Oncology, Stanford University School of Medicine, Stanford, CA
- Cancer Biology Program, Stanford University School of Medicine, Stanford, CA
| | - Mark O. Huising
- Department of Neurobiology, Physiology and Behavior, College of Biological Sciences, University of California, Davis, Davis, CA
- Department of Physiology and Membrane Biology, School of Medicine, University of California, Davis, Davis, CA
| | - Justin P. Annes
- Division of Endocrinology, Department of Medicine, Stanford University, Stanford, CA
- Stanford ChEM-H and Diabetes Research Center, Stanford University School of Medicine, Stanford, CA
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3
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Yu X, Xing Y, Zhang Y, Zhang P, He Y, Ghamsari F, Ramasubramanian MK, Wang Y, Ai H, Oberholzer J. Smartphone-microfluidic fluorescence imaging system for studying islet physiology. Front Endocrinol (Lausanne) 2022; 13:1039912. [PMID: 36440196 PMCID: PMC9684609 DOI: 10.3389/fendo.2022.1039912] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Accepted: 10/26/2022] [Indexed: 11/11/2022] Open
Abstract
Smartphone technology has been recently applied for biomedical image acquisition and data analysis due to its high-quality imaging capability, and flexibility to customize multi-purpose apps. In this work, we developed and characterized a smartphone-microfluidic fluorescence imaging system for studying the physiology of pancreatic islets. We further evaluated the system capability by performing real-time fluorescence imaging on mouse islets labeled with either chemical fluorescence dyes or genetically encoded fluorescent protein indicators (GEFPIs). Our results showed that the system was capable of analyzing key beta-cell insulin stimulator-release coupling factors in response to various stimuli with high-resolution dynamics. Furthermore, the integration of a microfluidics allowed high-resolution detection of insulin secretion at single islet level. When compared to conventional fluorescence microscopes and macro islet perifusion apparatus, the system has the advantages of low cost, portable, and easy to operate. With all of these features, we envision that this smartphone-microfluidic fluorescence imaging system can be applied to study islet physiology and clinical applications.
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Affiliation(s)
- Xiaoyu Yu
- Department of Surgery, University of Virginia, Charlottesville, VA, United States
| | - Yuan Xing
- Department of Surgery, University of Virginia, Charlottesville, VA, United States
| | - Yiyu Zhang
- Department of Molecular Physiology and Biological Physics, and Center for Membrane and Cell Physiology, University of Virginia, Charlottesville, VA, United States
| | - Pu Zhang
- Department of Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, VA, United States
| | - Yi He
- Department of Surgery, University of Virginia, Charlottesville, VA, United States
| | - Farid Ghamsari
- Department of Surgery, University of Virginia, Charlottesville, VA, United States
| | - Melur K. Ramasubramanian
- Department of Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, VA, United States
| | - Yong Wang
- Department of Surgery, University of Virginia, Charlottesville, VA, United States
| | - Huiwang Ai
- Department of Molecular Physiology and Biological Physics, and Center for Membrane and Cell Physiology, University of Virginia, Charlottesville, VA, United States
| | - Jose Oberholzer
- Department of Surgery, University of Virginia, Charlottesville, VA, United States
- *Correspondence: Jose Oberholzer,
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Fernández-Veledo S, Ceperuelo-Mallafré V, Vendrell J. Rethinking succinate: an unexpected hormone-like metabolite in energy homeostasis. Trends Endocrinol Metab 2021; 32:680-692. [PMID: 34301438 DOI: 10.1016/j.tem.2021.06.003] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 06/15/2021] [Accepted: 06/16/2021] [Indexed: 02/07/2023]
Abstract
There has been an explosion of interest in the signaling capacity of energy metabolites. A prime example is the Krebs cycle substrate succinate, an archetypal respiratory substrate with functions beyond energy production as an intracellular and extracellular signaling molecule. Long associated with inflammation, emerging evidence supports a key role for succinate in metabolic processes relating to energy management. As the natural ligand for SUCNR1, a G protein-coupled receptor, succinate is akin to hormones and likely functions as a reporter of metabolism and stress. In this review, we reconcile new and old observations to outline a regulatory role for succinate in metabolic homeostasis. We highlight the importance of the succinate-SUCNR1 axis in metabolic diseases as an integrator of macrophage immune response, and we discuss new metabolic functions recently ascribed to succinate in specific tissues. Because circulating succinate has emerged as a promising biomarker in chronic metabolic diseases, a better understanding of the physiopathological role of the succinate-SUCNR1 axis in metabolism might open new avenues for clinical use in patients with obesity or diabetes.
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Affiliation(s)
- Sonia Fernández-Veledo
- Department of Endocrinology and Nutrition and Research Unit, University Hospital of Tarragona Joan XXIII, Institut d'Investigació Sanitària Pere Virgili (IISPV), Tarragona, Spain; CIBER de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Madrid, Spain.
| | - Victòria Ceperuelo-Mallafré
- Department of Endocrinology and Nutrition and Research Unit, University Hospital of Tarragona Joan XXIII, Institut d'Investigació Sanitària Pere Virgili (IISPV), Tarragona, Spain; CIBER de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Madrid, Spain; Department of Medicine and Surgery, University Rovira I Virgili, Tarragona, Spain
| | - Joan Vendrell
- Department of Endocrinology and Nutrition and Research Unit, University Hospital of Tarragona Joan XXIII, Institut d'Investigació Sanitària Pere Virgili (IISPV), Tarragona, Spain; CIBER de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Madrid, Spain; Department of Medicine and Surgery, University Rovira I Virgili, Tarragona, Spain
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Liu M, Huang Y, Xu X, Li X, Alam M, Arunagiri A, Haataja L, Ding L, Wang S, Itkin-Ansari P, Kaufman RJ, Tsai B, Qi L, Arvan P. Normal and defective pathways in biogenesis and maintenance of the insulin storage pool. J Clin Invest 2021; 131:142240. [PMID: 33463547 PMCID: PMC7810482 DOI: 10.1172/jci142240] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Both basal and glucose-stimulated insulin release occur primarily by insulin secretory granule exocytosis from pancreatic β cells, and both are needed to maintain normoglycemia. Loss of insulin-secreting β cells, accompanied by abnormal glucose tolerance, may involve simple exhaustion of insulin reserves (which, by immunostaining, appears as a loss of β cell identity), or β cell dedifferentiation, or β cell death. While various sensing and signaling defects can result in diminished insulin secretion, somewhat less attention has been paid to diabetes risk caused by insufficiency in the biosynthetic generation and maintenance of the total insulin granule storage pool. This Review offers an overview of insulin biosynthesis, beginning with the preproinsulin mRNA (translation and translocation into the ER), proinsulin folding and export from the ER, and delivery via the Golgi complex to secretory granules for conversion to insulin and ultimate hormone storage. All of these steps are needed for generation and maintenance of the total insulin granule pool, and defects in any of these steps may, weakly or strongly, perturb glycemic control. The foregoing considerations have obvious potential relevance to the pathogenesis of type 2 diabetes and some forms of monogenic diabetes; conceivably, several of these concepts might also have implications for β cell failure in type 1 diabetes.
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Affiliation(s)
- Ming Liu
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Yumeng Huang
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Xiaoxi Xu
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Xin Li
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Maroof Alam
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Anoop Arunagiri
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Leena Haataja
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Li Ding
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Shusen Wang
- Organ Transplant Center, Tianjin First Central Hospital, Tianjin, China
| | | | - Randal J. Kaufman
- Degenerative Diseases Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California, USA
| | - Billy Tsai
- Department of Cell and Developmental Biology, and
| | - Ling Qi
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Peter Arvan
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, Michigan, USA
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Sayed NH, Fathy N, Kortam MA, Rabie MA, Mohamed AF, Kamel AS. Vildagliptin Attenuates Huntington's Disease through Activation of GLP-1 Receptor/PI3K/Akt/BDNF Pathway in 3-Nitropropionic Acid Rat Model. Neurotherapeutics 2020; 17:252-268. [PMID: 31728850 PMCID: PMC7007456 DOI: 10.1007/s13311-019-00805-5] [Citation(s) in RCA: 71] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Vildagliptin (Vilda), a dipeptidyl peptidase-4 (DPP-4) inhibitor, has been highlighted as a promising therapeutic agent for neurodegenerative diseases as Alzheimer's and Parkinson's diseases. Vilda's effect is mostly linked to PI3K/Akt signaling in CNS. Moreover, PI3K/Akt activation reportedly enhanced survival and dampened progression of Huntington's disease (HD). However, Vilda's role in HD is yet to be elucidated. Thus, the aim of the study is to uncover the potentiality of Vilda in HD and unfold its link with PI3K/Akt pathway in 3-nitropropionic acid (3NP) rat model. Rats were randomly assigned into 4 groups; group 1 received saline, whereas, groups 2, 3 and 4 received 3NP (10 mg/kg/day; i.p.) for 14 days, concomitantly with Vilda (5 mg/kg/day; p.o.) in groups 3 and 4, and wortmannin (WM), a PI3K inhibitor, (15 μg/kg/day; i.v.) in group 4. Vilda improved cognitive and motor perturbations induced by 3NP, as confirmed by striatal histopathological specimens and immunohistochemical examination of GFAP. The molecular signaling of Vilda was estimated by elevation of GLP-1 level and protein expressions of survival proteins; p85/p55 (pY458/199)-PI3K, pS473-Akt. Together, it boosted striatal neurotrophic factors and receptor; pS133-CREB, BDNF, pY515-TrKB, which subsequently maintained mitochondrial integrity, as indicated by enhancing both SDH and COX activities, and the redox modulators; Sirt1, Nrf2. Such neuroprotection restored imbalance of neurotransmitters through increasing GABA and suppressing glutamate as well PDE10A. These effects were reversed by WM pre-administration. In conclusion, Vilda purveyed significant anti-Huntington effect which may be mediated, at least in part, via activation of GLP-1/PI3K/Akt pathway in 3NP rat model.
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Affiliation(s)
- Noha H Sayed
- Department of Biochemistry, Faculty of Pharmacy, Cairo University, Governorate, Giza, Egypt
| | - Nevine Fathy
- Department of Biochemistry, Faculty of Pharmacy, Cairo University, Governorate, Giza, Egypt.
| | - Mona A Kortam
- Department of Biochemistry, Faculty of Pharmacy, Cairo University, Governorate, Giza, Egypt
| | - Mostafa A Rabie
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Cairo University, Governorate, Giza, Egypt
| | - Ahmed F Mohamed
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Cairo University, Governorate, Giza, Egypt
| | - Ahmed S Kamel
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Cairo University, Governorate, Giza, Egypt
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Boland BB, Rhodes CJ, Grimsby JS. The dynamic plasticity of insulin production in β-cells. Mol Metab 2017; 6:958-973. [PMID: 28951821 PMCID: PMC5605729 DOI: 10.1016/j.molmet.2017.04.010] [Citation(s) in RCA: 117] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Revised: 04/27/2017] [Accepted: 04/28/2017] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Although the insulin-producing pancreatic β-cells are quite capable of adapting to both acute and chronic changes in metabolic demand, persistently high demand for insulin will ultimately lead to their progressive dysfunction and eventual loss. Recent and historical studies highlight the importance of 'resting' the β-cell as a means of preserving functional β-cell mass. SCOPE OF REVIEW We provide experimental evidence to highlight the remarkable plasticity for insulin production and secretion by the pancreatic β-cell alongside some clinical evidence that supports leveraging this unique ability to preserve β-cell function. MAJOR CONCLUSIONS Treatment strategies for type 2 diabetes mellitus (T2DM) targeted towards reducing the systemic metabolic burden, rather than demanding greater insulin production from an already beleaguered β-cell, should be emphasized to maintain endogenous insulin secretory function and delay the progression of T2DM.
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Key Words
- ATF6, Activating Transcription Factor 6
- CHOP, CCAAT/Enhancer-Binding Homologous Protein
- EPAC, Exchange Factor Directly Activated by cAMP
- EROβ1, ER-resident oxidoreductase β1
- GIP, Gastric Inhibitory Polypeptide
- GLP-1, Glucagon-like Peptide 1
- GLUT2, Glucose Transporter 2
- GSIS, Glucose Stimulated Insulin Secretion
- IREα, Inositol Requiring Enzyme α
- Insulin production
- NEFA, Non-esterified Fatty Acid
- PERK, Protein Kinase RNA-like Endoplasmic Reticulum Kinase
- PKA, Protein Kinase A
- PKC, Protein Kinase C
- PLC, Phospholipase C
- ROS, Reactive Oxygen Species
- SNAP-25, Soluble NSF Attachment Protein 25
- SNARE, Soluble NSF Attachment Protein Receptor
- STZ, Streptozotocin
- T2DM
- T2DM, Type 2 Diabetes Mellitus
- TRP, Transient Receptor Potential
- VAMP-2, Vehicle Associated Membrane Protein 2
- VDCC, Voltage Dependent Calcium Channel
- mTORC1, Mammalian Target of Rapamycin 1
- nH, Hill coefficient
- β-cell rest
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Affiliation(s)
- Brandon B. Boland
- MedImmune, Cardiovascular and Metabolic Disease Research, 1 MedImmune Way, Gaithersburg, MD 20878, USA
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8
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Abstract
The pancreatic β-cell secretes insulin in response to elevated plasma glucose. This review applies an external bioenergetic critique to the central processes of glucose-stimulated insulin secretion, including glycolytic and mitochondrial metabolism, the cytosolic adenine nucleotide pool, and its interaction with plasma membrane ion channels. The control mechanisms responsible for the unique responsiveness of the cell to glucose availability are discussed from bioenergetic and metabolic control standpoints. The concept of coupling factor facilitation of secretion is critiqued, and an attempt is made to unravel the bioenergetic basis of the oscillatory mechanisms controlling secretion. The need to consider the physiological constraints operating in the intact cell is emphasized throughout. The aim is to provide a coherent pathway through an extensive, complex, and sometimes bewildering literature, particularly for those unfamiliar with the field.
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Affiliation(s)
- David G Nicholls
- Buck Institute for Research on Aging, Novato, California; and Department of Clinical Sciences, Unit of Molecular Metabolism, Lund University Diabetes Centre, Malmo, Sweden
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9
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Edalat A, Schulte-Mecklenbeck P, Bauer C, Undank S, Krippeit-Drews P, Drews G, Düfer M. Mitochondrial succinate dehydrogenase is involved in stimulus-secretion coupling and endogenous ROS formation in murine beta cells. Diabetologia 2015; 58:1532-41. [PMID: 25874444 DOI: 10.1007/s00125-015-3577-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Accepted: 03/13/2015] [Indexed: 10/23/2022]
Abstract
AIMS/HYPOTHESIS Generation of reduction equivalents is a prerequisite for nutrient-stimulated insulin secretion. Mitochondrial succinate dehydrogenase (SDH) fulfils a dual function with respect to mitochondrial energy supply: (1) the enzyme is part of mitochondrial respiratory chains; and (2) it catalyses oxidation of succinate to fumarate in the Krebs cycle. The aim of our study was to elucidate the significance of SDH for beta cell stimulus-secretion coupling (SSC). METHODS Mitochondrial variables, reactive oxygen species (ROS) and cytosolic Ca(2+) concentration ([Ca(2+)]c) were measured by fluorescence techniques and insulin release by radioimmunoassay in islets or islet cells of C57Bl/6N mice. RESULTS Inhibition of SDH with 3-nitropropionic acid (3-NPA) or monoethyl fumarate (MEF) reduced glucose-stimulated insulin secretion. Inhibition of the ATP-sensitive K(+) channel (KATP channel) partly prevented this effect, whereas potentiation of antioxidant defence by superoxide dismutase mimetics (TEMPOL and mito-TEMPO) or by nuclear factor erythroid 2-related factor 2 (Nrf-2)-mediated upregulation of antioxidant enzymes (oltipraz, tert-butylhydroxyquinone) did not diminish the inhibitory influence of 3-NPA. Blocking SDH decreased glucose-stimulated increase in intracellular FADH2 concentration without alterations in NAD(P)H. In addition, 3-NPA and MEF drastically reduced glucose-induced hyperpolarisation of mitochondrial membrane potential, indicative of decreased ATP production. As a consequence, the glucose-stimulated rise in [Ca(2+)]c was significantly delayed and reduced. Acute application of 3-NPA interrupted glucose-driven oscillations of [Ca(2+)]c. 3-NPA per se did not elevate intracellular ROS, but instead prevented glucose-induced ROS accumulation. CONCLUSIONS/INTERPRETATION SDH is an important regulator of insulin secretion and ROS production. Inhibition of SDH interrupts membrane-potential-dependent SSC, pointing to a pivotal role of mitochondrial FAD/FADH2 homeostasis for the maintenance of glycaemic control.
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Affiliation(s)
- Armin Edalat
- Department of Pharmaceutical and Medicinal Chemistry, University of Münster, Corrensstraße 48, 48149, Münster, Germany
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Wang C, Li X, Mu K, Li L, Wang S, Zhu Y, Zhang M, Ryu J, Xie Z, Shi D, Zhang WJ, Dong LQ, Jia W. Deficiency of APPL1 in mice impairs glucose-stimulated insulin secretion through inhibition of pancreatic beta cell mitochondrial function. Diabetologia 2013; 56:1999-2009. [PMID: 23793716 PMCID: PMC4556236 DOI: 10.1007/s00125-013-2971-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2012] [Accepted: 05/28/2013] [Indexed: 12/11/2022]
Abstract
AIMS/HYPOTHESIS Adaptor protein, phosphotyrosine interaction, pleckstrin homology domain and leucine zipper containing 1 (APPL1) is an adapter protein that positively mediates adiponectin signalling. Deficiency of APPL1 in the target tissues of insulin induces insulin resistance. We therefore aimed, in the present study, to determine its role in regulating pancreatic beta cell function. METHODS A hyperglycaemic clamp test was performed to determine insulin secretion in APPL1 knockout (KO) mice. Glucose- and adiponectin-induced insulin release was measured in islets from APPL1 KO mice or INS-1(832/13) cells with either APPL1 knockdown or overproduction. RT-PCR and western blotting were conducted to analyse gene expression and protein abundance. Oxygen consumption rate (OCR), ATP production and mitochondrial membrane potential were assayed to evaluate mitochondrial function. RESULTS APPL1 is highly expressed in pancreatic islets, but its levels are decreased in mice fed a high-fat diet and db/db mice compared with controls. Deletion of the Appl1 gene leads to impairment of both the first and second phases of insulin secretion during hyperglycaemic clamp tests. In addition, glucose-stimulated insulin secretion (GSIS) is significantly decreased in islets from APPL1 KO mice. Conversely, overproduction of APPL1 leads to an increase in GSIS in beta cells. In addition, expression levels of several genes involved in insulin production, mitochondrial biogenesis and mitochondrial OCR, ATP production and mitochondrial membrane potential are reduced significantly in APPL1-knockdown beta cells. Moreover, suppression or overexproduction of APPL1 inhibits or stimulates adiponectin-potentiated GSIS in beta cells, respectively. CONCLUSIONS/INTERPRETATION Our study demonstrates the roles of APPL1 in regulating GSIS and mitochondrial function in pancreatic beta cells, which implicates APPL1 as a therapeutic target in the treatment of type 2 diabetes.
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Affiliation(s)
- Chen Wang
- Department of Endocrinology and Metabolism, Shanghai Jiao Tong University Affiliated Sixth People’s Hospital, 600 Yishan Road, Shanghai 200233, People’s Republic of ChinaDiabetes Institute, Shanghai Jiao Tong University, Shanghai, People’s Republic of ChinaShanghai Key Laboratory of Diabetes Mellitus, Shanghai, People’s Republic of China
| | - Xiaowen Li
- Diabetes Institute, Shanghai Jiao Tong University, Shanghai, People’s Republic of ChinaShanghai Key Laboratory of Diabetes Mellitus, Shanghai, People’s Republic of China
| | - Kaida Mu
- Department of Endocrinology and Metabolism, Shanghai Jiao Tong University Affiliated Sixth People’s Hospital, 600 Yishan Road, Shanghai 200233, People’s Republic of ChinaDiabetes Institute, Shanghai Jiao Tong University, Shanghai, People’s Republic of ChinaShanghai Key Laboratory of Diabetes Mellitus, Shanghai, People’s Republic of China
| | - Ling Li
- Department of Endocrinology and Metabolism, Shanghai Jiao Tong University Affiliated Sixth People’s Hospital, 600 Yishan Road, Shanghai 200233, People’s Republic of ChinaDiabetes Institute, Shanghai Jiao Tong University, Shanghai, People’s Republic of China
| | - Shihong Wang
- Department of Endocrinology and Metabolism, Shanghai Jiao Tong University Affiliated Sixth People’s Hospital, 600 Yishan Road, Shanghai 200233, People’s Republic of ChinaDiabetes Institute, Shanghai Jiao Tong University, Shanghai, People’s Republic of ChinaShanghai Key Laboratory of Diabetes Mellitus, Shanghai, People’s Republic of China
| | - Yunxia Zhu
- Department of Endocrinology and Metabolism, Shanghai Jiao Tong University Affiliated Sixth People’s Hospital, 600 Yishan Road, Shanghai 200233, People’s Republic of ChinaDiabetes Institute, Shanghai Jiao Tong University, Shanghai, People’s Republic of ChinaShanghai Key Laboratory of Diabetes Mellitus, Shanghai, People’s Republic of China
| | - Mingliang Zhang
- Department of Endocrinology and Metabolism, Shanghai Jiao Tong University Affiliated Sixth People’s Hospital, 600 Yishan Road, Shanghai 200233, People’s Republic of ChinaDiabetes Institute, Shanghai Jiao Tong University, Shanghai, People’s Republic of ChinaShanghai Key Laboratory of Diabetes Mellitus, Shanghai, People’s Republic of China
| | - Jiyoon Ryu
- Department of Cellular and Structural Biology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229-3900, USA
| | - Zhifang Xie
- Department of Pathophysiology, Second Military Medical University, Shanghai, People’s Republic of China
| | - Dongyun Shi
- Department of Biochemistry and Molecular Biology, Shanghai Medical College of Fudan University, Shanghai, People’s Republic of China
| | - Weiping J. Zhang
- Department of Pathophysiology, Second Military Medical University, Shanghai, People’s Republic of China
| | - Lily Q. Dong
- Department of Cellular and Structural Biology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229-3900, USA
| | - Weiping Jia
- Department of Endocrinology and Metabolism, Shanghai Jiao Tong University Affiliated Sixth People’s Hospital, 600 Yishan Road, Shanghai 200233, People’s Republic of ChinaDiabetes Institute, Shanghai Jiao Tong University, Shanghai, People’s Republic of China
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Kruglov AG, Andersson MA, Mikkola R, Roivainen M, Kredics L, Saris NEL, Salkinoja-Salonen MS. Novel mycotoxin from Acremonium exuviarum is a powerful inhibitor of the mitochondrial respiratory chain complex III. Chem Res Toxicol 2010; 22:565-73. [PMID: 19193189 DOI: 10.1021/tx800317z] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
A novel mycotoxin named acrebol, consisting of two closely similar peptaibols (1726 and 1740 Da), was isolated from an indoor strain of the mitosporic ascomycete fungus Acremonium exuviarum. This paper describes the unique mitochondrial toxicity of acrebol, not earlier described for any peptaibol. Acrebol inhibited complex III of the respiratory chain of isolated rat liver mitochondria (1 mg of protein mL(-1)) with an IC(50) of approximately 80 ng mL(-1) (50 nM) after a short preincubation, and 350 ng mL(-1) caused immediate and complete inhibition. Acrebol thus is a complex III inhibitor almost as potent as antimycin A and myxothiazol but completely different in structure. Similarly to myxothiazol but in contrast to antimycin A, acrebol decreased the level of mitochondrial superoxide anion detectable by chemiluminescent probe 3,7-dihydro-2-methyl-6-(4-methoxyphenyl)imidazol[1,2-a]pyrazine-3-one. Unlike other peptaibols, acrebol in toxic concentrations did not increase the ionic and solute permeability of membranes of isolated rat liver mitochondria, did not induce disturbance of the ionic homeostasis or the osmotic balance of mitochondria, and did not release apoptogenic proteins like cytochrome c from the intermembrane space of mitochondria. In boar spermatozoa, acrebol inhibited the respiratory chain and caused ATP depletion by activation of the oligomycin-sensitive F(0)F(1)-ATPase, which resulted in the inhibition of the progressive movement. In mouse insulinoma MIN-6 cells, whose energy supply solely depends on oxidative phosphorylation, acrebol induced necrosis-like death. The pathophysiological relevance of these findings is discussed.
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Affiliation(s)
- Alexey G Kruglov
- Department of Applied Chemistry and Microbiology, University of Helsinki, P.O. Box 56, FIN-00014 Helsinki, Finland
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12
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Role of mitochondria in beta-cell function and dysfunction. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2010; 654:193-216. [PMID: 20217499 DOI: 10.1007/978-90-481-3271-3_9] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Pancreatic beta-cells are poised to sense glucose and other nutrient secretagogues to regulate insulin exocytosis, thereby maintaining glucose homeostasis. This process requires translation of metabolic substrates into intracellular messengers recognized by the exocytotic machinery. Central to this metabolism-secretion coupling, mitochondria integrate and generate metabolic signals, thereby connecting glucose recognition to insulin exocytosis. In response to a glucose rise, nucleotides and metabolites are generated by mitochondria and participate, together with cytosolic calcium, to the stimulation of insulin release. This review describes the mitochondrion-dependent pathways of regulated insulin secretion. Mitochondrial defects, such as mutations and reactive oxygen species production, are discussed in the context of beta-cell failure that may participate to the etiology of diabetes.
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Weksler-Zangen S, Raz I, Lenzen S, Jörns A, Ehrenfeld S, Amir G, Oprescu A, Yagil Y, Yagil C, Zangen DH, Kaiser N. Impaired glucose-stimulated insulin secretion is coupled with exocrine pancreatic lesions in the Cohen diabetic rat. Diabetes 2008; 57:279-87. [PMID: 17977959 DOI: 10.2337/db07-0520] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVE The Cohen diabetes-sensitive rat develops postprandial hyperglycemia when fed a high-sucrose, copper-poor diet, whereas the Cohen diabetes-resistant rat maintains normoglycemia. The pathophysiological basis of diabetes was studied in the Cohen diabetic rat centering on the interplay between the exocrine and endocrine compartments of the pancreas. RESEARCH DESIGN AND METHODS Studies used male Cohen diabetes-sensitive and Cohen diabetes-resistant rats fed 1-month high-sucrose, copper-poor diet. Serum insulin and glucose levels were measured during glucose and insulin tolerance tests. The pancreas was evaluated for weight, insulin content, macrophage, and fat infiltration. Glucose-stimulated insulin secretion (GSIS) was determined in isolated perfused pancreas and in islets. RESULTS Hyperglycemic Cohen diabetes-sensitive rats exhibited reduced pancreatic weight with lipid deposits and interleukin-1beta-positive macrophage infiltration in the exocrine pancreas. Islet morphology was preserved, and total pancreatic insulin content did not differ from that of Cohen diabetes-resistant rats. Lipids did not accumulate in skeletal muscle, nor was insulin resistance observed in hyperglycemic Cohen diabetes-sensitive rats. Intravenous glucose-tolerance test revealed markedly elevated glucose levels associated with diminished insulin output. Insulin release was induced in vivo by the non-nutrient secretagogues arginine and tolbutamide, suggesting a selective unresponsiveness to glucose. Decreased GSIS was observed in the isolated perfused pancreas of the hyperglycemic Cohen diabetes-sensitive rat, whereas islets isolated from these rats exhibited glucose-dependent insulin secretion and proinsulin biosynthesis. CONCLUSIONS The association of the in vivo insulin secretory defect with lipid accumulation and activated macrophage infiltration in the exocrine pancreas suggests that changes in the islet microenvironment are the culprit in the insulin secretory malfunction observed in vivo.
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Affiliation(s)
- Sarah Weksler-Zangen
- The Diabetes Unit, Hadassah-Hebrew University Medical Center, Jerusalem 1200, Israel.
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14
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Rivas-Carrillo JD, Soto-Gutierrez A, Navarro-Alvarez N, Noguchi H, Okitsu T, Chen Y, Yuasa T, Tanaka K, Narushima M, Miki A, Misawa H, Tabata Y, Jun HS, Matsumoto S, Fox IJ, Tanaka N, Kobayashi N. Cell-permeable pentapeptide V5 inhibits apoptosis and enhances insulin secretion, allowing experimental single-donor islet transplantation in mice. Diabetes 2007; 56:1259-67. [PMID: 17287463 DOI: 10.2337/db06-1679] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
OBJECTIVE Treatment of diabetic patients by pancreatic islet transplantation often requires the use of islets from two to four donors to produce insulin independence in a single recipient. Following isolation and transplantation, islets are susceptible to apoptosis, which limits their function and probably long-term islet graft survival. RESEARCH DESIGN AND METHODS To address this issue, we examined the effect of the cell-permeable apoptosis inhibitor pentapeptide Val-Pro-Met-Leu-Lys, V5, on pancreatic islets in a mouse model. RESULTS V5 treatment upregulated expression of anti-apoptotic proteins Bcl-2 and XIAP (X-linked inhibitor of apoptosis protein) by more than 3- and 11-fold and downregulated expression of apoptosis-inducing proteins Bax, Bad, and nuclear factor-kappaB-p65 by 10, 30, and nearly 50%, respectively. Treatment improved the recovered islet mass following collagenase digestion and isolation by 44% and in vitro glucose-responsive insulin secretion nearly fourfold. Following transplantation in streptozotocin-induced diabetic mice, 150 V5-treated islet equivalents functioned as well as 450 control untreated islet equivalents in normalizing blood glucose. CONCLUSIONS These studies indicate that inhibition of apoptosis by V5 significantly improves islet function following isolation and improves islet graft function following transplantation. Use of this reagent in clinical islet transplantation could have a dramatic impact on the number of patients that might benefit from this therapy and could affect long-term graft survival.
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Affiliation(s)
- Jorge D Rivas-Carrillo
- Department of Surgery, Okayama University Graduate School of Medicine and Dentistry, Shikata-cho, Okayama, Japan
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15
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Attali V, Parnes M, Ariav Y, Cerasi E, Kaiser N, Leibowitz G. Regulation of insulin secretion and proinsulin biosynthesis by succinate. Endocrinology 2006; 147:5110-8. [PMID: 16916949 DOI: 10.1210/en.2006-0496] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Succinate stimulates insulin secretion and proinsulin biosynthesis. We studied the effects of reduced nicotinamide adenine dinucleotide phosphate (NADPH)-modulating pathways on glucose- and succinate-stimulated insulin secretion and proinsulin biosynthesis in the rat and the insulin-resistant Psammomys obesus. Disruption of the anaplerotic pyruvate/malate shuttle by phenylacetic acid inhibited glucose- and succinate-stimulated insulin secretion and succinate-stimulated proinsulin biosynthesis in both species. In contrast, phenylacetic acid failed to inhibit glucose-stimulated proinsulin biosynthesis in P. obesus islets. Inhibition of the NADPH-consuming enzyme neuronal nitric oxide synthase (nNOS) with l-N(G)-nitro-l-arginine methyl ester or with N(G)-monomethyl-l-arginine(G) doubled succinate-stimulated insulin secretion in rat islets, suggesting that succinate- and nNOS-derived signals interact to regulate insulin secretion. In contrast, nNOS inhibition had no effect on succinate-stimulated proinsulin biosynthesis in both species. In P. obesus islets, insulin secretion was not stimulated by succinate in the absence of glucose, whereas proinsulin biosynthesis was increased 5-fold. Conversely, under stimulating glucose levels, succinate doubled insulin secretion, indicating glucose-dependence. Pyruvate ester and inhibition of nNOS partially mimicked the permissive effect of glucose on succinate-stimulated insulin secretion, suggesting that anaplerosis-derived signals render the beta-cells responsive to succinate. We conclude that beta-cell anaplerosis via pyruvate carboxylase is important for glucose- and succinate-stimulated insulin secretion and for succinate-stimulated proinsulin biosynthesis. In P. obesus, pyruvate/malate shuttle dependent and independent pathways that regulate proinsulin biosynthesis coexist; the latter can maintain fuel stimulated biosynthetic activity when the succinate-dependent pathway is inhibited. nNOS signaling is a negative regulator of insulin secretion, but not of proinsulin biosynthesis.
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Affiliation(s)
- Veronique Attali
- Endocrinology and Metabolism Service, Department of Internal Medicine, Hadassah-Hebrew University Medical Center, P.O. Box 12000, Jerusalem 91120, Israel
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Maechler P, Carobbio S, Rubi B. In beta-cells, mitochondria integrate and generate metabolic signals controlling insulin secretion. Int J Biochem Cell Biol 2006; 38:696-709. [PMID: 16443386 DOI: 10.1016/j.biocel.2005.12.006] [Citation(s) in RCA: 99] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2005] [Revised: 12/08/2005] [Accepted: 12/12/2005] [Indexed: 12/14/2022]
Abstract
Pancreatic beta-cells are unique neuroendocrine cells displaying the peculiar feature of responding to nutrients, principally glucose, as primary stimulus. This requires translation of a metabolic substrate into intracellular messengers recognized by the exocytotic machinery. Central to this signal transduction mechanism, mitochondria integrate and generate metabolic signals, thereby coupling glucose recognition to insulin secretion. In response to a glucose rise, nucleotides and metabolites are generated by mitochondria and participate, together with cytosolic calcium, to the stimulation of insulin exocytosis. This review describes the mitochondrion-dependent pathways of regulated insulin secretion. In particular, importance of cataplerotic and anaplerotic processes is discussed, with special attention to the mitochondrial enzyme glutamate dehydrogenase. Mitochondrial defects, such as mutations and reactive oxygen species production, are presented in the context of beta-cell failure in the course of type 2 diabetes.
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Affiliation(s)
- Pierre Maechler
- Department of Cell Physiology and Metabolism, University Medical Centre, Geneva, Switzerland.
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Kaiser N, Nesher R, Donath MY, Fraenkel M, Behar V, Magnan C, Ktorza A, Cerasi E, Leibowitz G. Psammomys obesus, a model for environment-gene interactions in type 2 diabetes. Diabetes 2005; 54 Suppl 2:S137-44. [PMID: 16306331 DOI: 10.2337/diabetes.54.suppl_2.s137] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Type 2 diabetes is characterized by insulin resistance and progressive beta-cell failure. Deficient insulin secretion, with increased proportions of insulin precursor molecules, is a common feature of type 2 diabetes; this could result from inappropriate beta-cell function and/or reduced beta-cell mass. Most studies using tissues from diabetic patients are retrospective, providing only limited information on the relative contribution of beta-cell dysfunction versus decreased beta-cell mass to the "beta-cell failure" of type 2 diabetes. The gerbil Psammomys obesus is a good model to address questions related to the role of insulin resistance and beta-cell failure in nutritionally induced diabetes. Upon a change from its natural low-calorie diet to the calorie-rich laboratory food, P. obesus develops moderate obesity associated with postprandial hyperglycemia. Continued dietary load, superimposed on its innate insulin resistance, results in depletion of pancreatic insulin stores, with increased proportions of insulin precursor molecules in the pancreas and the blood. Inadequate response of the preproinsulin gene to the increased insulin needs is an important cause of diabetes progression. Changes in beta-cell mass do not correlate with pancreatic insulin stores and are unlikely to play a role in disease initiation and progression. The major culprit is the inappropriate insulin production with depletion of insulin stores as a consequence. Similar mechanisms could operate during the evolution of type 2 diabetes in humans.
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Affiliation(s)
- Nurit Kaiser
- Endocrinology and Metabolism Service, Department of Internal Medicine, Hebrew University-Hadassah Medical Center, Jerusalem, Israel.
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