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Rohli KE, Stubbe NJ, Walker EM, Pearson GL, Soleimanpour SA, Stephens SB. A metabolic redox relay supports ER proinsulin export in pancreatic islet β cells. JCI Insight 2024; 9:e178725. [PMID: 38935435 PMCID: PMC11383593 DOI: 10.1172/jci.insight.178725] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Accepted: 06/18/2024] [Indexed: 06/29/2024] Open
Abstract
ER stress and proinsulin misfolding are heralded as contributing factors to β cell dysfunction in type 2 diabetes, yet how ER function becomes compromised is not well understood. Recent data identify altered ER redox homeostasis as a critical mechanism that contributes to insulin granule loss in diabetes. Hyperoxidation of the ER delays proinsulin export and limits the proinsulin supply available for insulin granule formation. In this report, we identified glucose metabolism as a critical determinant in the redox homeostasis of the ER. Using multiple β cell models, we showed that loss of mitochondrial function or inhibition of cellular metabolism elicited ER hyperoxidation and delayed ER proinsulin export. Our data further demonstrated that β cell ER redox homeostasis was supported by the metabolic supply of reductive redox donors. We showed that limiting NADPH and thioredoxin flux delayed ER proinsulin export, whereas thioredoxin-interacting protein suppression restored ER redox and proinsulin trafficking. Taken together, we propose that β cell ER redox homeostasis is buffered by cellular redox donor cycles, which are maintained through active glucose metabolism.
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Affiliation(s)
- Kristen E Rohli
- Fraternal Order of Eagles Diabetes Research Center
- Interdisciplinary Graduate Program in Genetics, and
- Division of Endocrinology and Metabolism, Department of Internal Medicine, University of Iowa, Iowa City, Iowa, USA
| | | | - Emily M Walker
- Division of Metabolism, Endocrinology and Diabetes, Department of Internal Medicine, and
| | - Gemma L Pearson
- Division of Metabolism, Endocrinology and Diabetes, Department of Internal Medicine, and
| | - Scott A Soleimanpour
- Division of Metabolism, Endocrinology and Diabetes, Department of Internal Medicine, and
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan, USA
- VA Ann Arbor Healthcare System, Ann Arbor, Michigan, USA
| | - Samuel B Stephens
- Fraternal Order of Eagles Diabetes Research Center
- Interdisciplinary Graduate Program in Genetics, and
- Division of Endocrinology and Metabolism, Department of Internal Medicine, University of Iowa, Iowa City, Iowa, USA
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2
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Sharma C, Hamza A, Boyle E, Donu D, Cen Y. Post-Translational Modifications and Diabetes. Biomolecules 2024; 14:310. [PMID: 38540730 PMCID: PMC10968569 DOI: 10.3390/biom14030310] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2024] [Revised: 03/01/2024] [Accepted: 03/04/2024] [Indexed: 09/22/2024] Open
Abstract
Diabetes and its associated complications have increasingly become major challenges for global healthcare. The current therapeutic strategies involve insulin replacement therapy for type 1 diabetes (T1D) and small-molecule drugs for type 2 diabetes (T2D). Despite these advances, the complex nature of diabetes necessitates innovative clinical interventions for effective treatment and complication prevention. Accumulative evidence suggests that protein post-translational modifications (PTMs), including glycosylation, phosphorylation, acetylation, and SUMOylation, play important roles in diabetes and its pathological consequences. Therefore, the investigation of these PTMs not only sheds important light on the mechanistic regulation of diabetes but also opens new avenues for targeted therapies. Here, we offer a comprehensive overview of the role of several PTMs in diabetes, focusing on the most recent advances in understanding their functions and regulatory mechanisms. Additionally, we summarize the pharmacological interventions targeting PTMs that have advanced into clinical trials for the treatment of diabetes. Current challenges and future perspectives are also provided.
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Affiliation(s)
- Chiranjeev Sharma
- Department of Medicinal Chemistry, Virginia Commonwealth University, Richmond, VA 23219, USA; (C.S.); (A.H.); (E.B.); (D.D.)
| | - Abu Hamza
- Department of Medicinal Chemistry, Virginia Commonwealth University, Richmond, VA 23219, USA; (C.S.); (A.H.); (E.B.); (D.D.)
| | - Emily Boyle
- Department of Medicinal Chemistry, Virginia Commonwealth University, Richmond, VA 23219, USA; (C.S.); (A.H.); (E.B.); (D.D.)
| | - Dickson Donu
- Department of Medicinal Chemistry, Virginia Commonwealth University, Richmond, VA 23219, USA; (C.S.); (A.H.); (E.B.); (D.D.)
| | - Yana Cen
- Department of Medicinal Chemistry, Virginia Commonwealth University, Richmond, VA 23219, USA; (C.S.); (A.H.); (E.B.); (D.D.)
- Institute for Structural Biology, Drug Discovery and Development, Virginia Commonwealth University, Richmond, VA 23219, USA
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3
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Lin H, Suzuki K, Smith N, Li X, Nalbach L, Fuentes S, Spigelman AF, Dai XQ, Bautista A, Ferdaoussi M, Aggarwal S, Pepper AR, Roma LP, Ampofo E, Li WH, MacDonald PE. A role and mechanism for redox sensing by SENP1 in β-cell responses to high fat feeding. Nat Commun 2024; 15:334. [PMID: 38184650 PMCID: PMC10771529 DOI: 10.1038/s41467-023-44589-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Accepted: 12/21/2023] [Indexed: 01/08/2024] Open
Abstract
Pancreatic β-cells respond to metabolic stress by upregulating insulin secretion, however the underlying mechanisms remain unclear. Here we show, in β-cells from overweight humans without diabetes and mice fed a high-fat diet for 2 days, insulin exocytosis and secretion are enhanced without increased Ca2+ influx. RNA-seq of sorted β-cells suggests altered metabolic pathways early following high fat diet, where we find increased basal oxygen consumption and proton leak, but a more reduced cytosolic redox state. Increased β-cell exocytosis after 2-day high fat diet is dependent on this reduced intracellular redox state and requires the sentrin-specific SUMO-protease-1. Mice with either pancreas- or β-cell-specific deletion of this fail to up-regulate exocytosis and become rapidly glucose intolerant after 2-day high fat diet. Mechanistically, redox-sensing by the SUMO-protease requires a thiol group at C535 which together with Zn+-binding suppresses basal protease activity and unrestrained β-cell exocytosis, and increases enzyme sensitivity to regulation by redox signals.
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Affiliation(s)
- Haopeng Lin
- Department of Pharmacology, University of Alberta, Edmonton, AB, T6G 2E1, Canada
- Alberta Diabetes Institute, University of Alberta, Edmonton, AB, T6G 2E1, Canada
- Guangzhou Laboratory, Guangzhou, 510005, Guangdong, China
| | - Kunimasa Suzuki
- Department of Pharmacology, University of Alberta, Edmonton, AB, T6G 2E1, Canada
- Alberta Diabetes Institute, University of Alberta, Edmonton, AB, T6G 2E1, Canada
| | - Nancy Smith
- Department of Pharmacology, University of Alberta, Edmonton, AB, T6G 2E1, Canada
- Alberta Diabetes Institute, University of Alberta, Edmonton, AB, T6G 2E1, Canada
| | - Xi Li
- Departments of Cell Biology and Biochemistry, University of Texas Southwestern Medical Center, 6000 Harry Hines Blvd., Dallas, TX, 75390-9039, USA
| | - Lisa Nalbach
- Institute for Clinical & Experimental Surgery, Saarland University, Homburg/Saar, Germany
- Biophysics Department, Center for Human and Molecular Biology, Saarland University, Homburg/Saar, Germany
| | - Sonia Fuentes
- Departments of Cell Biology and Biochemistry, University of Texas Southwestern Medical Center, 6000 Harry Hines Blvd., Dallas, TX, 75390-9039, USA
| | - Aliya F Spigelman
- Department of Pharmacology, University of Alberta, Edmonton, AB, T6G 2E1, Canada
- Alberta Diabetes Institute, University of Alberta, Edmonton, AB, T6G 2E1, Canada
| | - Xiao-Qing Dai
- Department of Pharmacology, University of Alberta, Edmonton, AB, T6G 2E1, Canada
- Alberta Diabetes Institute, University of Alberta, Edmonton, AB, T6G 2E1, Canada
| | - Austin Bautista
- Department of Pharmacology, University of Alberta, Edmonton, AB, T6G 2E1, Canada
- Alberta Diabetes Institute, University of Alberta, Edmonton, AB, T6G 2E1, Canada
| | - Mourad Ferdaoussi
- Faculty Saint-Jean, University of Alberta, Edmonton, AB, T6G 2E1, Canada
| | - Saloni Aggarwal
- Department of Surgery, University of Alberta, Edmonton, AB, T6G 2E1, Canada
| | - Andrew R Pepper
- Department of Surgery, University of Alberta, Edmonton, AB, T6G 2E1, Canada
| | - Leticia P Roma
- Biophysics Department, Center for Human and Molecular Biology, Saarland University, Homburg/Saar, Germany
| | - Emmanuel Ampofo
- Institute for Clinical & Experimental Surgery, Saarland University, Homburg/Saar, Germany
| | - Wen-Hong Li
- Departments of Cell Biology and Biochemistry, University of Texas Southwestern Medical Center, 6000 Harry Hines Blvd., Dallas, TX, 75390-9039, USA
| | - Patrick E MacDonald
- Department of Pharmacology, University of Alberta, Edmonton, AB, T6G 2E1, Canada.
- Alberta Diabetes Institute, University of Alberta, Edmonton, AB, T6G 2E1, Canada.
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Sharma P, Bhatia K, Singh Kapoor H, Kaur B, Khetarpal P. Genetic variants of metabolism and inflammatory pathways, and PCOS risk -Systematic review, meta-analysis, and in-silico analysis. Gene 2023; 888:147796. [PMID: 37714276 DOI: 10.1016/j.gene.2023.147796] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 09/05/2023] [Accepted: 09/11/2023] [Indexed: 09/17/2023]
Abstract
IMPORTANCE Identification of genetic risk factors for PCOS susceptibility. OBJECTIVE To identify genetic risk variants of the genes involved in metabolic or inflammatory pathways. DATA SOURCES Relevant literature was identified and extracted from PubMed, Central Cochrane Library, Google Scholar, and Science Direct by using a set of keywords related to pre-determined genes up to 06 May 2023. Study selection and synthesis: PRISMA guidelines were followed to design the protocol which is registered in PROSPERO (CRD42023422501). Pooled odds ratio (OR) and 95% confidence interval (95% CI) for different gene variants were calculated under different genetic models (dominant model, recessive model, additive model, and allele model) by using Review Manager software 4.2. MAIN OUTCOMES Metabolic genetic variants FTO rs9939609, IL-6 rs1800795 and CAPN10 rs3842570, rs2975760, and RAB5B rs705702 are associated with PCOS risk. RESULTS Forty-four relevant articles have been identified for genes involved in metabolic (n = 23) or inflammatory pathways (n = 21). There is a significant association (p < 0.05) of IL-6 rs1800795 and FTO rs9939609 with increased risk.CAPN10 rs2975760 Ins allele is suggested as a protective factor among only the non-Asian population. Also, a significant association of CAPN10 rs2975760 and RAB5B rs705702 with increased risk among the Asian population is suggested. However, no significant association could be found between CAPN10 rs3792267, rs5030952, and SUMO1P1 rs2272046, and the risk of PCOS in any of the subpopulations analysed. In silico analysis suggests the deleterious effect of IL-6 rs1800795. CONCLUSION and relevance: The study suggests the role of various genetic variants for genetic predisposition to PCOS among different subpopulations.
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Affiliation(s)
- Priya Sharma
- Laboratory for Reproductive and Developmental Disorders, Department of Human Genetics and Molecular Medicine, School of Health Sciences, Central University of Punjab, Bathinda 151401, India
| | - Kabir Bhatia
- Department of Human Genetics and Molecular Medicine, School of Health Science, Central University of Punjab, Bathinda 151401, India
| | | | - Balpreet Kaur
- Department of Obstetrics and Gynaecology, AIIMS, Bathinda 151001, India
| | - Preeti Khetarpal
- Laboratory for Reproductive and Developmental Disorders, Department of Human Genetics and Molecular Medicine, School of Health Sciences, Central University of Punjab, Bathinda 151401, India.
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Chen YC, Taylor AJ, Fulcher JM, Swensen AC, Dai XQ, Komba M, Wrightson KL, Fok K, Patterson AE, Klein Geltink RI, MacDonald PE, Qian WJ, Verchere CB. Deletion of Carboxypeptidase E in β-Cells Disrupts Proinsulin Processing but Does Not Lead to Spontaneous Development of Diabetes in Mice. Diabetes 2023; 72:1277-1288. [PMID: 37364047 PMCID: PMC10450824 DOI: 10.2337/db22-0945] [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: 04/17/2023] [Accepted: 06/22/2023] [Indexed: 06/28/2023]
Abstract
Carboxypeptidase E (CPE) facilitates the conversion of prohormones into mature hormones and is highly expressed in multiple neuroendocrine tissues. Carriers of CPE mutations have elevated plasma proinsulin and develop severe obesity and hyperglycemia. We aimed to determine whether loss of Cpe in pancreatic β-cells disrupts proinsulin processing and accelerates development of diabetes and obesity in mice. Pancreatic β-cell-specific Cpe knockout mice (βCpeKO; Cpefl/fl x Ins1Cre/+) lack mature insulin granules and have elevated proinsulin in plasma; however, glucose-and KCl-stimulated insulin secretion in βCpeKO islets remained intact. High-fat diet-fed βCpeKO mice showed weight gain and glucose tolerance comparable with those of Wt littermates. Notably, β-cell area was increased in chow-fed βCpeKO mice and β-cell replication was elevated in βCpeKO islets. Transcriptomic analysis of βCpeKO β-cells revealed elevated glycolysis and Hif1α-target gene expression. On high glucose challenge, β-cells from βCpeKO mice showed reduced mitochondrial membrane potential, increased reactive oxygen species, reduced MafA, and elevated Aldh1a3 transcript levels. Following multiple low-dose streptozotocin injections, βCpeKO mice had accelerated development of hyperglycemia with reduced β-cell insulin and Glut2 expression. These findings suggest that Cpe and proper proinsulin processing are critical in maintaining β-cell function during the development of hyperglycemia. ARTICLE HIGHLIGHTS Carboxypeptidase E (Cpe) is an enzyme that removes the carboxy-terminal arginine and lysine residues from peptide precursors. Mutations in CPE lead to obesity and type 2 diabetes in humans, and whole-body Cpe knockout or mutant mice are obese and hyperglycemic and fail to convert proinsulin to insulin. We show that β-cell-specific Cpe deletion in mice (βCpeKO) does not lead to the development of obesity or hyperglycemia, even after prolonged high-fat diet treatment. However, β-cell proliferation rate and β-cell area are increased, and the development of hyperglycemia induced by multiple low-dose streptozotocin injections is accelerated in βCpeKO mice.
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Affiliation(s)
- Yi-Chun Chen
- Department of Surgery, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
- BC Children’s Hospital Research Institute, Vancouver, British Columbia, Canada
| | - Austin J. Taylor
- BC Children’s Hospital Research Institute, Vancouver, British Columbia, Canada
- Department of Pathology and Laboratory Medicine, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - James M. Fulcher
- Integrative Omics, Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA
| | - Adam C. Swensen
- Integrative Omics, Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA
| | - Xiao-Qing Dai
- Department of Pharmacology, University of Alberta, Edmonton, Alberta, Canada
| | - Mitsuhiro Komba
- Department of Surgery, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
- BC Children’s Hospital Research Institute, Vancouver, British Columbia, Canada
| | | | - Kenny Fok
- BC Children’s Hospital Research Institute, Vancouver, British Columbia, Canada
| | - Annette E. Patterson
- BC Children’s Hospital Research Institute, Vancouver, British Columbia, Canada
- Department of Pathology and Laboratory Medicine, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Ramon I. Klein Geltink
- BC Children’s Hospital Research Institute, Vancouver, British Columbia, Canada
- Department of Pathology and Laboratory Medicine, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | | | - Wei-Jun Qian
- Integrative Omics, Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA
| | - C. Bruce Verchere
- Department of Surgery, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
- BC Children’s Hospital Research Institute, Vancouver, British Columbia, Canada
- Department of Pathology and Laboratory Medicine, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
- Centre for Molecular Medicine and Therapeutics, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
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6
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Yang C, Wei M, Zhao Y, Yang Z, Song M, Mi J, Yang X, Tian G. Regulation of insulin secretion by the post-translational modifications. Front Cell Dev Biol 2023; 11:1217189. [PMID: 37601108 PMCID: PMC10436566 DOI: 10.3389/fcell.2023.1217189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Accepted: 07/24/2023] [Indexed: 08/22/2023] Open
Abstract
Post-translational modification (PTM) has a significant impact on cellular signaling and function regulation. In pancreatic β cells, PTMs are involved in insulin secretion, cell development, and viability. The dysregulation of PTM in β cells is clinically associated with the development of diabetes mellitus. Here, we summarized current findings on major PTMs occurring in β cells and their roles in insulin secretion. Our work provides comprehensive insight into understanding the mechanisms of insulin secretion and potential therapeutic targets for diabetes from the perspective of protein PTMs.
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Affiliation(s)
- Chunhua Yang
- Shandong Technology Innovation Center of Molecular Targeting and Intelligent Diagnosis and Treatment, Binzhou Medical University, Yantai, Shandong, China
| | - Mengna Wei
- Shandong Technology Innovation Center of Molecular Targeting and Intelligent Diagnosis and Treatment, Binzhou Medical University, Yantai, Shandong, China
| | - Yanpu Zhao
- Shandong Technology Innovation Center of Molecular Targeting and Intelligent Diagnosis and Treatment, Binzhou Medical University, Yantai, Shandong, China
| | - Zhanyi Yang
- Shandong Technology Innovation Center of Molecular Targeting and Intelligent Diagnosis and Treatment, Binzhou Medical University, Yantai, Shandong, China
| | - Mengyao Song
- Shandong Technology Innovation Center of Molecular Targeting and Intelligent Diagnosis and Treatment, Binzhou Medical University, Yantai, Shandong, China
| | - Jia Mi
- Shandong Technology Innovation Center of Molecular Targeting and Intelligent Diagnosis and Treatment, Binzhou Medical University, Yantai, Shandong, China
| | - Xiaoyong Yang
- Yale Center for Molecular and Systems Metabolism, Department of Comparative Medicine, Department of Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT, United States
| | - Geng Tian
- Shandong Technology Innovation Center of Molecular Targeting and Intelligent Diagnosis and Treatment, Binzhou Medical University, Yantai, Shandong, China
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7
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Wu X, Xu M, Geng M, Chen S, Little PJ, Xu S, Weng J. Targeting protein modifications in metabolic diseases: molecular mechanisms and targeted therapies. Signal Transduct Target Ther 2023; 8:220. [PMID: 37244925 PMCID: PMC10224996 DOI: 10.1038/s41392-023-01439-y] [Citation(s) in RCA: 44] [Impact Index Per Article: 44.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 03/01/2023] [Accepted: 04/06/2023] [Indexed: 05/29/2023] Open
Abstract
The ever-increasing prevalence of noncommunicable diseases (NCDs) represents a major public health burden worldwide. The most common form of NCD is metabolic diseases, which affect people of all ages and usually manifest their pathobiology through life-threatening cardiovascular complications. A comprehensive understanding of the pathobiology of metabolic diseases will generate novel targets for improved therapies across the common metabolic spectrum. Protein posttranslational modification (PTM) is an important term that refers to biochemical modification of specific amino acid residues in target proteins, which immensely increases the functional diversity of the proteome. The range of PTMs includes phosphorylation, acetylation, methylation, ubiquitination, SUMOylation, neddylation, glycosylation, palmitoylation, myristoylation, prenylation, cholesterylation, glutathionylation, S-nitrosylation, sulfhydration, citrullination, ADP ribosylation, and several novel PTMs. Here, we offer a comprehensive review of PTMs and their roles in common metabolic diseases and pathological consequences, including diabetes, obesity, fatty liver diseases, hyperlipidemia, and atherosclerosis. Building upon this framework, we afford a through description of proteins and pathways involved in metabolic diseases by focusing on PTM-based protein modifications, showcase the pharmaceutical intervention of PTMs in preclinical studies and clinical trials, and offer future perspectives. Fundamental research defining the mechanisms whereby PTMs of proteins regulate metabolic diseases will open new avenues for therapeutic intervention.
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Affiliation(s)
- Xiumei Wu
- Department of Endocrinology, Institute of Endocrine and Metabolic Diseases, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, Clinical Research Hospital of Chinese Academy of Sciences (Hefei), University of Science and Technology of China, Hefei, Anhui, 230001, China
- Department of Endocrinology and Metabolism, Guangdong Provincial Key Laboratory of Diabetology, The Third Affiliated Hospital of Sun Yat-sen University, 510000, Guangzhou, China
| | - Mengyun Xu
- Department of Endocrinology, Institute of Endocrine and Metabolic Diseases, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, Clinical Research Hospital of Chinese Academy of Sciences (Hefei), University of Science and Technology of China, Hefei, Anhui, 230001, China
| | - Mengya Geng
- Department of Endocrinology, Institute of Endocrine and Metabolic Diseases, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, Clinical Research Hospital of Chinese Academy of Sciences (Hefei), University of Science and Technology of China, Hefei, Anhui, 230001, China
| | - Shuo Chen
- Department of Endocrinology, Institute of Endocrine and Metabolic Diseases, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, Clinical Research Hospital of Chinese Academy of Sciences (Hefei), University of Science and Technology of China, Hefei, Anhui, 230001, China
| | - Peter J Little
- School of Pharmacy, University of Queensland, Pharmacy Australia Centre of Excellence, Woolloongabba, QLD, 4102, Australia
- Sunshine Coast Health Institute and School of Health and Behavioural Sciences, University of the Sunshine Coast, Birtinya, QLD, 4575, Australia
| | - Suowen Xu
- Department of Endocrinology, Institute of Endocrine and Metabolic Diseases, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, Clinical Research Hospital of Chinese Academy of Sciences (Hefei), University of Science and Technology of China, Hefei, Anhui, 230001, China
| | - Jianping Weng
- Department of Endocrinology, Institute of Endocrine and Metabolic Diseases, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, Clinical Research Hospital of Chinese Academy of Sciences (Hefei), University of Science and Technology of China, Hefei, Anhui, 230001, China.
- Department of Endocrinology and Metabolism, Guangdong Provincial Key Laboratory of Diabetology, The Third Affiliated Hospital of Sun Yat-sen University, 510000, Guangzhou, China.
- Bengbu Medical College, Bengbu, 233000, China.
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Hu A, Zou H, Chen B, Zhong J. Posttranslational modifications in diabetes: Mechanisms and functions. Rev Endocr Metab Disord 2022; 23:1011-1033. [PMID: 35697961 DOI: 10.1007/s11154-022-09740-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/20/2022] [Indexed: 12/15/2022]
Abstract
As one of the most widespread chronic diseases, diabetes and its accompanying complications affect approximately one tenth of individuals worldwide and represent a growing cause of morbidity and mortality. Accumulating evidence has proven that the process of diabetes is complex and interactive, involving various cellular responses and signaling cascades by posttranslational modifications (PTMs). Therefore, understanding the mechanisms and functions of PTMs in regulatory networks has fundamental importance for understanding the prediction, onset, diagnosis, progression, and treatment of diabetes. In this review, we offer a holistic summary and illustration of the crosstalk between PTMs and diabetes, including both types 1 and 2. Meanwhile, we discuss the potential use of PTMs in diabetes treatment and provide a prospective direction for deeply understanding the metabolic diseases.
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Affiliation(s)
- Ang Hu
- Key Laboratory of Prevention and Treatment of Cardiovascular and Cerebrovascular Diseases, Ministry of Education, Gannan Medical University, 323 National Road, Ganzhou, 341000, Jiangxi, China
| | - Haohong Zou
- Key Laboratory of Prevention and Treatment of Cardiovascular and Cerebrovascular Diseases, Ministry of Education, Gannan Medical University, 323 National Road, Ganzhou, 341000, Jiangxi, China
| | - Bin Chen
- Key Laboratory of Prevention and Treatment of Cardiovascular and Cerebrovascular Diseases, Ministry of Education, Gannan Medical University, 323 National Road, Ganzhou, 341000, Jiangxi, China
- The First Affiliated Hospital of Gannan Medical University, Ganzhou, China
| | - Jianing Zhong
- Key Laboratory of Prevention and Treatment of Cardiovascular and Cerebrovascular Diseases, Ministry of Education, Gannan Medical University, 323 National Road, Ganzhou, 341000, Jiangxi, China.
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9
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Ishihara H. Metabolism-secretion coupling in glucose-stimulated insulin secretion. Diabetol Int 2022; 13:463-470. [PMID: 35693987 PMCID: PMC9174369 DOI: 10.1007/s13340-022-00576-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2022] [Accepted: 02/27/2022] [Indexed: 01/09/2023]
Abstract
Pancreatic β-cells in the islets of Langerhans secrete insulin in response to blood glucose levels. Precise control of the amount of insulin secreted is of critical importance for maintaining systemic carbohydrate homeostasis. It is now well established that glucose induced production of ATP from ADP and the KATP channel closure elevate cytosolic Ca2+, triggering insulin exocytosis in β-cells. However, for full activation of insulin secretion by glucose, other mechanisms besides Ca2+ elevation are needed. These mechanisms are the targets of current research and include intracellular metabolic pathways branching from glycolysis. They are metabolic pathways originating from the TCA cycle intermediates, the glycerolipid/free fatty acid cycle and the pentose phosphate pathway. Signaling effects of these pathways including degradation (removal) of protein SUMOylation, modulation of insulin vesicular energetics, and lipid modulation of exocytotic machinery may converge to fulfill insulin secretion, though the precise mechanisms have yet to be elucidated. This mini-review summarize recent advances in research on metabolic coupling mechanisms functioning in insulin secretion.
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Affiliation(s)
- Hisamitsu Ishihara
- Division of Diabetes and Metabolism, Nihon University School of Medicine, 30-1 Oyaguchi-kamicho, Itabashi-ku, Tokyo, 173-8610 Japan
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10
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Rohli KE, Boyer CK, Blom SE, Stephens SB. Nutrient Regulation of Pancreatic Islet β-Cell Secretory Capacity and Insulin Production. Biomolecules 2022; 12:335. [PMID: 35204835 PMCID: PMC8869698 DOI: 10.3390/biom12020335] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 02/16/2022] [Accepted: 02/17/2022] [Indexed: 01/27/2023] Open
Abstract
Pancreatic islet β-cells exhibit tremendous plasticity for secretory adaptations that coordinate insulin production and release with nutritional demands. This essential feature of the β-cell can allow for compensatory changes that increase secretory output to overcome insulin resistance early in Type 2 diabetes (T2D). Nutrient-stimulated increases in proinsulin biosynthesis may initiate this β-cell adaptive compensation; however, the molecular regulators of secretory expansion that accommodate the increased biosynthetic burden of packaging and producing additional insulin granules, such as enhanced ER and Golgi functions, remain poorly defined. As these adaptive mechanisms fail and T2D progresses, the β-cell succumbs to metabolic defects resulting in alterations to glucose metabolism and a decline in nutrient-regulated secretory functions, including impaired proinsulin processing and a deficit in mature insulin-containing secretory granules. In this review, we will discuss how the adaptative plasticity of the pancreatic islet β-cell's secretory program allows insulin production to be carefully matched with nutrient availability and peripheral cues for insulin signaling. Furthermore, we will highlight potential defects in the secretory pathway that limit or delay insulin granule biosynthesis, which may contribute to the decline in β-cell function during the pathogenesis of T2D.
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Affiliation(s)
- Kristen E. Rohli
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA 52242, USA; (K.E.R.); (C.K.B.); (S.E.B.)
- Division of Endocrinology and Metabolism, Department of Internal Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Cierra K. Boyer
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA 52242, USA; (K.E.R.); (C.K.B.); (S.E.B.)
- Department of Neuroscience and Pharmacology, University of Iowa, Iowa City, IA 52242, USA
| | - Sandra E. Blom
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA 52242, USA; (K.E.R.); (C.K.B.); (S.E.B.)
- Division of Endocrinology and Metabolism, Department of Internal Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Samuel B. Stephens
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA 52242, USA; (K.E.R.); (C.K.B.); (S.E.B.)
- Division of Endocrinology and Metabolism, Department of Internal Medicine, University of Iowa, Iowa City, IA 52242, USA
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11
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Glucose-6-phosphatase catalytic subunit 2 negatively regulates glucose oxidation and insulin secretion in pancreatic β-cells. J Biol Chem 2022; 298:101729. [PMID: 35176280 PMCID: PMC8941207 DOI: 10.1016/j.jbc.2022.101729] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Revised: 02/11/2022] [Accepted: 02/12/2022] [Indexed: 12/11/2022] Open
Abstract
Elevated fasting blood glucose (FBG) is associated with increased risks of developing type 2 diabetes (T2D) and cardiovascular-associated mortality. G6PC2 is predominantly expressed in islets, encodes a glucose-6-phosphatase catalytic subunit that converts glucose-6-phosphate (G6P) to glucose, and has been linked with variations in FBG in genome-wide association studies. Deletion of G6pc2 in mice has been shown to lower FBG without affecting fasting plasma insulin levels in vivo. At 5 mM glucose, pancreatic islets from G6pc2 knockout (KO) mice exhibit no glucose cycling, increased glycolytic flux, and enhanced glucose-stimulated insulin secretion (GSIS). However, the broader effects of G6pc2 KO on β-cell metabolism and redox regulation are unknown. Here we used CRISPR/Cas9 gene editing and metabolic flux analysis in βTC3 cells, a murine pancreatic β-cell line, to examine the role of G6pc2 in regulating glycolytic and mitochondrial fluxes. We found that deletion of G6pc2 led to ∼60% increases in glycolytic and citric acid cycle (CAC) fluxes at both 5 and 11 mM glucose concentrations. Furthermore, intracellular insulin content and GSIS were enhanced by approximately two-fold, along with increased cytosolic redox potential and reductive carboxylation flux. Normalization of fluxes relative to net glucose uptake revealed upregulation in two NADPH-producing pathways in the CAC. These results demonstrate that G6pc2 regulates GSIS by modulating not only glycolysis but also, independently, citric acid cycle activity in β-cells. Overall, our findings implicate G6PC2 as a potential therapeutic target for enhancing insulin secretion and lowering FBG, which could benefit individuals with prediabetes, T2D, and obesity.
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12
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Nan J, Lee JS, Moon JH, Lee SA, Park YJ, Lee DS, Chung SS, Park KS. SENP2 regulates mitochondrial function and insulin secretion in pancreatic β cells. Exp Mol Med 2022; 54:72-80. [PMID: 35064188 PMCID: PMC8814193 DOI: 10.1038/s12276-021-00723-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 09/22/2021] [Accepted: 10/29/2021] [Indexed: 01/01/2023] Open
Abstract
AbstractIncreasing evidence has shown that small ubiquitin-like modifier (SUMO) modification plays an important role in metabolic regulation. We previously demonstrated that SUMO-specific protease 2 (SENP2) is involved in lipid metabolism in skeletal muscle and adipogenesis. In this study, we investigated the function of SENP2 in pancreatic β cells by generating a β cell-specific knockout (Senp2-βKO) mouse model. Glucose tolerance and insulin secretion were significantly impaired in the Senp2-βKO mice. In addition, glucose-stimulated insulin secretion (GSIS) was decreased in the islets of the Senp2-βKO mice without a significant change in insulin synthesis. Furthermore, islets of the Senp2-βKO mice exhibited enlarged mitochondria and lower oxygen consumption rates, accompanied by lower levels of S616 phosphorylated DRP1 (an active form of DRP1), a mitochondrial fission protein. Using a cell culture system of NIT-1, an islet β cell line, we found that increased SUMO2/3 conjugation to DRP1 due to SENP2 deficiency suppresses the phosphorylation of DRP1, which possibly induces mitochondrial dysfunction. In addition, SENP2 overexpression restored GSIS impairment induced by DRP1 knockdown and increased DRP1 phosphorylation. Furthermore, palmitate treatment decreased phosphorylated DRP1 and GSIS in β cells, which was rescued by SENP2 overexpression. These results suggest that SENP2 regulates mitochondrial function and insulin secretion at least in part by modulating the phosphorylation of DRP1 in pancreatic β cells.
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13
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Kalwat MA, Scheuner D, Rodrigues-dos-Santos K, Eizirik DL, Cobb MH. The Pancreatic ß-cell Response to Secretory Demands and Adaption to Stress. Endocrinology 2021; 162:bqab173. [PMID: 34407177 PMCID: PMC8459449 DOI: 10.1210/endocr/bqab173] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Indexed: 02/06/2023]
Abstract
Pancreatic β cells dedicate much of their protein translation capacity to producing insulin to maintain glucose homeostasis. In response to increased secretory demand, β cells can compensate by increasing insulin production capability even in the face of protracted peripheral insulin resistance. The ability to amplify insulin secretion in response to hyperglycemia is a critical facet of β-cell function, and the exact mechanisms by which this occurs have been studied for decades. To adapt to the constant and fast-changing demands for insulin production, β cells use the unfolded protein response of the endoplasmic reticulum. Failure of these compensatory mechanisms contributes to both type 1 and 2 diabetes. Additionally, studies in which β cells are "rested" by reducing endogenous insulin demand have shown promise as a therapeutic strategy that could be applied more broadly. Here, we review recent findings in β cells pertaining to the metabolic amplifying pathway, the unfolded protein response, and potential advances in therapeutics based on β-cell rest.
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Affiliation(s)
- Michael A Kalwat
- Indiana Biosciences Research Institute, Indianapolis, IN 46202, USA
| | - Donalyn Scheuner
- Indiana Biosciences Research Institute, Indianapolis, IN 46202, USA
| | | | - Decio L Eizirik
- Indiana Biosciences Research Institute, Indianapolis, IN 46202, USA
- ULB Center for Diabetes Research, Medical Faculty, Université Libre de Bruxelles, Brussels, Belgium
| | - Melanie H Cobb
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
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14
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Lin H, Smith N, Spigelman AF, Suzuki K, Ferdaoussi M, Alghamdi TA, Lewandowski SL, Jin Y, Bautista A, Wang YW, Manning Fox JE, Merrins MJ, Buteau J, MacDonald PE. β-Cell Knockout of SENP1 Reduces Responses to Incretins and Worsens Oral Glucose Tolerance in High-Fat Diet-Fed Mice. Diabetes 2021; 70:2626-2638. [PMID: 34462260 PMCID: PMC8564408 DOI: 10.2337/db20-1235] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Accepted: 08/19/2021] [Indexed: 01/17/2023]
Abstract
SUMOylation reduces oxidative stress and preserves islet mass at the expense of robust insulin secretion. To investigate a role for the deSUMOylating enzyme sentrin-specific protease 1 (SENP1) following metabolic stress, we put pancreas/gut-specific SENP1 knockout (pSENP1-KO) mice on a high-fat diet (HFD). Male pSENP1-KO mice were more glucose intolerant following HFD than littermate controls but only in response to oral glucose. A similar phenotype was observed in females. Plasma glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide 1 (GLP-1) responses were identical in pSENP1-KO and wild-type littermates, including the HFD-induced upregulation of GIP responses. Islet mass was not different, but insulin secretion and β-cell exocytotic responses to the GLP-1 receptor agonist exendin-4 (Ex4) and GIP were impaired in islets lacking SENP1. Glucagon secretion from pSENP1-KO islets was also reduced, so we generated β-cell-specific SENP1 KO mice. These phenocopied the pSENP1-KO mice with selective impairment in oral glucose tolerance following HFD, preserved islet mass expansion, and impaired β-cell exocytosis and insulin secretion to Ex4 and GIP without changes in cAMP or Ca2+ levels. Thus, β-cell SENP1 limits oral glucose intolerance following HFD by ensuring robust insulin secretion at a point downstream of incretin signaling.
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Affiliation(s)
- Haopeng Lin
- Department of Pharmacology, University of Alberta, Edmonton, Alberta, Canada
- Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Nancy Smith
- Department of Pharmacology, University of Alberta, Edmonton, Alberta, Canada
- Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Aliya F Spigelman
- Department of Pharmacology, University of Alberta, Edmonton, Alberta, Canada
- Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Kunimasa Suzuki
- Department of Pharmacology, University of Alberta, Edmonton, Alberta, Canada
- Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Mourad Ferdaoussi
- Department of Pediatrics, University of Alberta, Edmonton, Alberta, Canada
| | - Tamadher A Alghamdi
- Department of Pharmacology, University of Alberta, Edmonton, Alberta, Canada
- Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Sophie L Lewandowski
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Wisconsin-Madison
| | - Yaxing Jin
- Department of Pharmacology, University of Alberta, Edmonton, Alberta, Canada
| | - Austin Bautista
- Department of Pharmacology, University of Alberta, Edmonton, Alberta, Canada
- Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Ying Wayne Wang
- Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada
| | - Jocelyn E Manning Fox
- Department of Pharmacology, University of Alberta, Edmonton, Alberta, Canada
- Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Matthew J Merrins
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Wisconsin-Madison
| | - Jean Buteau
- Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada
| | - Patrick E MacDonald
- Department of Pharmacology, University of Alberta, Edmonton, Alberta, Canada
- Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada
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15
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Bauchle CJ, Rohli KE, Boyer CK, Pal V, Rocheleau JV, Liu S, Imai Y, Taylor EB, Stephens SB. Mitochondrial Efflux of Citrate and Isocitrate Is Fully Dispensable for Glucose-Stimulated Insulin Secretion and Pancreatic Islet β-Cell Function. Diabetes 2021; 70:1717-1728. [PMID: 34039628 PMCID: PMC8385611 DOI: 10.2337/db21-0037] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Accepted: 05/22/2021] [Indexed: 11/13/2022]
Abstract
The defining feature of pancreatic islet β-cell function is the precise coordination of changes in blood glucose levels with insulin secretion to regulate systemic glucose homeostasis. While ATP has long been heralded as a critical metabolic coupling factor to trigger insulin release, glucose-derived metabolites have been suggested to further amplify fuel-stimulated insulin secretion. The mitochondrial export of citrate and isocitrate through the citrate-isocitrate carrier (CIC) has been suggested to initiate a key pathway that amplifies glucose-stimulated insulin secretion, though the physiological significance of β-cell CIC-to-glucose homeostasis has not been established. Here, we generated constitutive and adult CIC β-cell knockout (KO) mice and demonstrate that these animals have normal glucose tolerance, similar responses to diet-induced obesity, and identical insulin secretion responses to various fuel secretagogues. Glucose-stimulated NADPH production was impaired in β-cell CIC KO islets, whereas glutathione reduction was retained. Furthermore, suppression of the downstream enzyme cytosolic isocitrate dehydrogenase (Idh1) inhibited insulin secretion in wild-type islets but failed to impact β-cell function in β-cell CIC KO islets. Our data demonstrate that the mitochondrial CIC is not required for glucose-stimulated insulin secretion and that additional complexities exist for the role of Idh1 and NADPH in the regulation of β-cell function.
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Affiliation(s)
- Casey J Bauchle
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA
- Division of Endocrinology and Metabolism, Department of Internal Medicine, University of Iowa, Iowa City, IA
| | - Kristen E Rohli
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA
- Interdisciplinary Graduate Program in Genetics, University of Iowa, Iowa City, IA
| | - Cierra K Boyer
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA
- Department of Pharmacology, University of Iowa, Iowa City, IA
| | - Vidhant Pal
- Institute of Biomedical Engineering, Toronto, Ontario, Canada
- Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Jonathan V Rocheleau
- Institute of Biomedical Engineering, Toronto, Ontario, Canada
- Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Siming Liu
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA
- Division of Endocrinology and Metabolism, Department of Internal Medicine, University of Iowa, Iowa City, IA
| | - Yumi Imai
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA
- Division of Endocrinology and Metabolism, Department of Internal Medicine, University of Iowa, Iowa City, IA
- Pappajohn Biomedical Institute, University of Iowa, Iowa City, IA
- Iowa City Veterans Affairs Medical Center, Iowa City, IA
| | - Eric B Taylor
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA
- Pappajohn Biomedical Institute, University of Iowa, Iowa City, IA
- Department of Molecular Physiology and Biophysics, University of Iowa, Iowa City, IA
| | - Samuel B Stephens
- Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, IA
- Division of Endocrinology and Metabolism, Department of Internal Medicine, University of Iowa, Iowa City, IA
- Interdisciplinary Graduate Program in Genetics, University of Iowa, Iowa City, IA
- Pappajohn Biomedical Institute, University of Iowa, Iowa City, IA
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16
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Zhang GF, Jensen MV, Gray SM, El K, Wang Y, Lu D, Becker TC, Campbell JE, Newgard CB. Reductive TCA cycle metabolism fuels glutamine- and glucose-stimulated insulin secretion. Cell Metab 2021; 33:804-817.e5. [PMID: 33321098 PMCID: PMC8115731 DOI: 10.1016/j.cmet.2020.11.020] [Citation(s) in RCA: 79] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 11/06/2020] [Accepted: 11/25/2020] [Indexed: 12/11/2022]
Abstract
Metabolic fuels regulate insulin secretion by generating second messengers that drive insulin granule exocytosis, but the biochemical pathways involved are incompletely understood. Here we demonstrate that stimulation of rat insulinoma cells or primary rat islets with glucose or glutamine + 2-aminobicyclo-(2,2,1)-heptane-2-carboxylic acid (Gln + BCH) induces reductive, "counter-clockwise" tricarboxylic acid (TCA) cycle flux of glutamine to citrate. Molecular or pharmacologic suppression of isocitrate dehydrogenase-2 (IDH2), which catalyzes reductive carboxylation of 2-ketoglutarate to isocitrate, results in impairment of glucose- and Gln + BCH-stimulated reductive TCA cycle flux, lowering of NADPH levels, and inhibition of insulin secretion. Pharmacologic suppression of IDH2 also inhibits insulin secretion in living mice. Reductive TCA cycle flux has been proposed as a mechanism for generation of biomass in cancer cells. Here we demonstrate that reductive TCA cycle flux also produces stimulus-secretion coupling factors that regulate insulin secretion, including in non-dividing cells.
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Affiliation(s)
- Guo-Fang Zhang
- Sarah W. Stedman Nutrition and Metabolism Center and Duke Molecular Physiology Institute, Duke University Medical Center, Durham, NC 27701, USA; Department of Medicine, Endocrinology and Metabolism Division, Duke University Medical Center, Durham, NC 27701, USA
| | - Mette V Jensen
- Sarah W. Stedman Nutrition and Metabolism Center and Duke Molecular Physiology Institute, Duke University Medical Center, Durham, NC 27701, USA
| | - Sarah M Gray
- Sarah W. Stedman Nutrition and Metabolism Center and Duke Molecular Physiology Institute, Duke University Medical Center, Durham, NC 27701, USA
| | - Kimberley El
- Sarah W. Stedman Nutrition and Metabolism Center and Duke Molecular Physiology Institute, Duke University Medical Center, Durham, NC 27701, USA
| | - You Wang
- Sarah W. Stedman Nutrition and Metabolism Center and Duke Molecular Physiology Institute, Duke University Medical Center, Durham, NC 27701, USA
| | - Danhong Lu
- Sarah W. Stedman Nutrition and Metabolism Center and Duke Molecular Physiology Institute, Duke University Medical Center, Durham, NC 27701, USA
| | - Thomas C Becker
- Sarah W. Stedman Nutrition and Metabolism Center and Duke Molecular Physiology Institute, Duke University Medical Center, Durham, NC 27701, USA; Department of Medicine, Endocrinology and Metabolism Division, Duke University Medical Center, Durham, NC 27701, USA
| | - Jonathan E Campbell
- Sarah W. Stedman Nutrition and Metabolism Center and Duke Molecular Physiology Institute, Duke University Medical Center, Durham, NC 27701, USA; Department of Medicine, Endocrinology and Metabolism Division, Duke University Medical Center, Durham, NC 27701, USA; Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27701, USA
| | - Christopher B Newgard
- Sarah W. Stedman Nutrition and Metabolism Center and Duke Molecular Physiology Institute, Duke University Medical Center, Durham, NC 27701, USA; Department of Medicine, Endocrinology and Metabolism Division, Duke University Medical Center, Durham, NC 27701, USA; Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27701, USA.
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17
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Campbell JE, Newgard CB. Mechanisms controlling pancreatic islet cell function in insulin secretion. Nat Rev Mol Cell Biol 2021; 22:142-158. [PMID: 33398164 DOI: 10.1038/s41580-020-00317-7] [Citation(s) in RCA: 278] [Impact Index Per Article: 92.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/19/2020] [Indexed: 02/07/2023]
Abstract
Metabolic homeostasis in mammals is tightly regulated by the complementary actions of insulin and glucagon. The secretion of these hormones from pancreatic β-cells and α-cells, respectively, is controlled by metabolic, endocrine, and paracrine regulatory mechanisms and is essential for the control of blood levels of glucose. The deregulation of these mechanisms leads to various pathologies, most notably type 2 diabetes, which is driven by the combined lesions of impaired insulin action and a loss of the normal insulin secretion response to glucose. Glucose stimulates insulin secretion from β-cells in a bi-modal fashion, and new insights about the underlying mechanisms, particularly relating to the second or amplifying phase of this secretory response, have been recently gained. Other recent work highlights the importance of α-cell-produced proglucagon-derived peptides, incretin hormones from the gastrointestinal tract and other dietary components, including certain amino acids and fatty acids, in priming and potentiation of the β-cell glucose response. These advances provide a new perspective for the understanding of the β-cell failure that triggers type 2 diabetes.
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Affiliation(s)
- Jonathan E Campbell
- Sarah W. Stedman Nutrition and Metabolism Center and Duke Molecular Physiology Institute, Duke University Medical Center, Durham, NC, USA.,Department of Medicine, Endocrinology and Metabolism Division, Duke University Medical Center, Durham, NC, USA.,Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC, USA
| | - Christopher B Newgard
- Sarah W. Stedman Nutrition and Metabolism Center and Duke Molecular Physiology Institute, Duke University Medical Center, Durham, NC, USA. .,Department of Medicine, Endocrinology and Metabolism Division, Duke University Medical Center, Durham, NC, USA. .,Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC, USA.
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18
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Silveirinha VC, Lin H, Tanifuji S, Mochida S, Cottrell GS, Cimarosti H, Stephens GJ. Ca V2.2 (N-type) voltage-gated calcium channels are activated by SUMOylation pathways. Cell Calcium 2021; 93:102326. [PMID: 33360835 DOI: 10.1016/j.ceca.2020.102326] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Revised: 11/01/2020] [Accepted: 11/23/2020] [Indexed: 11/21/2022]
Abstract
SUMOylation is an important post-translational modification process involving covalent attachment of SUMO (Small Ubiquitin-like MOdifier) protein to target proteins. Here, we investigated the potential for SUMO-1 protein to modulate the function of the CaV2.2 (N-type) voltage-gated calcium channel (VGCC), a protein vital for presynaptic neurotransmitter release. Co-expression of SUMO-1, but not the conjugation-deficient mutant SUMO-1ΔGG, increased heterologously-expressed CaV2.2 Ca2+ current density, an effect potentiated by the conjugating enzyme Ubc9. Expression of sentrin-specific protease (SENP)-1 or Ubc9 alone, had no effect on recombinant CaV2.2 channels. Co-expression of SUMO-1 and Ubc9 caused an increase in whole-cell maximal conductance (Gmax) and a hyperpolarizing shift in the midpoint of activation (V1/2). Mutation of all five CaV2.2 lysine residues to arginine within the five highest probability (>65 %) SUMOylation consensus motifs (SCMs) (construct CaV2.2-Δ5KR), produced a loss-of-function mutant. Mutagenesis of selected individual lysine residues identified K394, but not K951, as a key residue for SUMO-1-mediated increase in CaV2.2 Ca2+ current density. In synaptically-coupled superior cervical ganglion (SCG) neurons, SUMO-1 protein was distributed throughout the cell body, axons and dendrites and presumptive presynaptic terminals, whilst SUMO-1ΔGG protein was largely confined to the cell body, in particular, the nucleus. SUMO-1 expression caused increases in paired excitatory postsynaptic potential (EPSP) ratio at short (20-120 ms) inter-stimuli intervals in comparison to SUMO-1ΔGG, consistent with an increase in residual presynaptic Ca2+ current and an increase in release probability of synaptic vesicles. Together, these data provide evidence for CaV2.2 VGCCs as novel targets for SUMOylation pathways.
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Affiliation(s)
- Vasco C Silveirinha
- School of Pharmacy, University of Reading, Whiteknights, Reading, RG6 6AJ, UK
| | - Hong Lin
- School of Pharmacy, University of Reading, Whiteknights, Reading, RG6 6AJ, UK
| | - Shota Tanifuji
- Dept of Physiology, Tokyo Medical University, Tokyo, Japan
| | - Sumiko Mochida
- Dept of Physiology, Tokyo Medical University, Tokyo, Japan
| | - Graeme S Cottrell
- School of Pharmacy, University of Reading, Whiteknights, Reading, RG6 6AJ, UK
| | - Helena Cimarosti
- School of Pharmacy, University of Reading, Whiteknights, Reading, RG6 6AJ, UK.
| | - Gary J Stephens
- School of Pharmacy, University of Reading, Whiteknights, Reading, RG6 6AJ, UK.
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19
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Li N, Luo X, Yu Q, Yang P, Chen Z, Wang X, Jiang J, Xu J, Gong Q, Eizirik DL, Zhou Z, Zhao J, Xiong F, Zhang S, Wang CY. SUMOylation of Pdia3 exacerbates proinsulin misfolding and ER stress in pancreatic beta cells. J Mol Med (Berl) 2020; 98:1795-1807. [PMID: 33159537 DOI: 10.1007/s00109-020-02006-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Revised: 10/16/2020] [Accepted: 10/30/2020] [Indexed: 12/18/2022]
Abstract
SUMOylation has long been recognized to regulate multiple biological processes in pancreatic beta cells, but its impact on proinsulin disulfide maturation and endoplasmic reticulum (ER) stress remains elusive. Herein, we conducted comparative proteomic analyses of SUMOylated proteins in primary mouse/human islets following proinflammatory cytokine stimulation. Cytokine challenge rendered beta cells to undergo a SUMOylation turnover manifested by the changes of SUMOylation substrates and SUMOylation levels for multiple substrates. Our data support that SUMOylation may play a crucial role to regulate proinsulin misfolding and ER stress at least by targeting Protein Disulfide Isomerase a3 (Pdia3). SUMOylation regulates Pdia3 enzymatic activity, subcellular localization, and protein binding ability. Furthermore, SUMOylation of Pdia3 exacerbated proinsulin misfolding and ER stress, and repressed Stat3 activation. In contrast, disruption of Pdia3 SUMOylation markedly rescued the outcomes. Collectively, our study expands the understanding how SUMOylation regulates ER stress in beta cells, which shed light on developing potential strategies against beta cell dysfunction.
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Affiliation(s)
- Na Li
- The Center for Biomedical Research, Tongji Hospital Research Building, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430000, China
| | - Xi Luo
- The Center for Biomedical Research, Tongji Hospital Research Building, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430000, China
| | - Qilin Yu
- The Center for Biomedical Research, Tongji Hospital Research Building, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430000, China
| | - Ping Yang
- The Center for Biomedical Research, Tongji Hospital Research Building, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430000, China
| | - Zhishui Chen
- The Center for Biomedical Research, Tongji Hospital Research Building, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430000, China.,Key Laboratory of Organ Transplantation, Ministry of Education, NHC Key Laboratory of Organ Transplantation, Key Laboratory of Organ Transplantation, Chinese Academy of Medical Sciences, Tongji Hospital Research Building, Tongji Hospital, Wuhan, China
| | - Xinqiang Wang
- The Center for Biomedical Research, Tongji Hospital Research Building, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430000, China.,Key Laboratory of Organ Transplantation, Ministry of Education, NHC Key Laboratory of Organ Transplantation, Key Laboratory of Organ Transplantation, Chinese Academy of Medical Sciences, Tongji Hospital Research Building, Tongji Hospital, Wuhan, China
| | - Jipin Jiang
- The Center for Biomedical Research, Tongji Hospital Research Building, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430000, China.,Key Laboratory of Organ Transplantation, Ministry of Education, NHC Key Laboratory of Organ Transplantation, Key Laboratory of Organ Transplantation, Chinese Academy of Medical Sciences, Tongji Hospital Research Building, Tongji Hospital, Wuhan, China
| | - Jing Xu
- The Center for Biomedical Research, Tongji Hospital Research Building, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430000, China.,Key Laboratory of Organ Transplantation, Ministry of Education, NHC Key Laboratory of Organ Transplantation, Key Laboratory of Organ Transplantation, Chinese Academy of Medical Sciences, Tongji Hospital Research Building, Tongji Hospital, Wuhan, China
| | - Quan Gong
- Clinical Molecular Immunology Center, Department of Immunology, School of Medicine, Yangtze University, Jingzhou, 434023, China
| | - Decio L Eizirik
- ULB Center for Diabetes Research, Université Libre de Bruxelles, 808 Route de Lennik, B-1070, Brussels, Belgium.,Indiana Biosciences Research Institute (IBRI), Indianapolis, IN, USA
| | - Zhiguang Zhou
- Diabetes Center, the Second Xiangya Hospital, Institute of Metabolism and Endocrinology, Central South University, Changsha, China
| | - Jiajun Zhao
- Department of Endocrinology and Metabolism, Shandong Provincial Hospital affiliated to Shandong First Medical University, Jinan, China
| | - Fei Xiong
- The Center for Biomedical Research, Tongji Hospital Research Building, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430000, China. .,Key Laboratory of Organ Transplantation, Ministry of Education, NHC Key Laboratory of Organ Transplantation, Key Laboratory of Organ Transplantation, Chinese Academy of Medical Sciences, Tongji Hospital Research Building, Tongji Hospital, Wuhan, China.
| | - Shu Zhang
- The Center for Biomedical Research, Tongji Hospital Research Building, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430000, China. .,Key Laboratory of Organ Transplantation, Ministry of Education, NHC Key Laboratory of Organ Transplantation, Key Laboratory of Organ Transplantation, Chinese Academy of Medical Sciences, Tongji Hospital Research Building, Tongji Hospital, Wuhan, China.
| | - Cong-Yi Wang
- The Center for Biomedical Research, Tongji Hospital Research Building, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430000, China. .,Key Laboratory of Organ Transplantation, Ministry of Education, NHC Key Laboratory of Organ Transplantation, Key Laboratory of Organ Transplantation, Chinese Academy of Medical Sciences, Tongji Hospital Research Building, Tongji Hospital, Wuhan, China.
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20
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Abstract
Sentrin/small ubiquitin-like modifier (SUMO) is protein modification pathway that regulates multiple biological processes, including cell division, DNA replication/repair, signal transduction, and cellular metabolism. In this review, we will focus on recent advances in the mechanisms of disease pathogenesis, such as cancer, diabetes, seizure, and heart failure, which have been linked to the SUMO pathway. SUMO is conjugated to lysine residues in target proteins through an isopeptide linkage catalyzed by SUMO-specific activating (E1), conjugating (E2), and ligating (E3) enzymes. In steady state, the quantity of SUMO-modified substrates is usually a small fraction of unmodified substrates due to the deconjugation activity of the family Sentrin/SUMO-specific proteases (SENPs). In contrast to the complexity of the ubiquitination/deubiquitination machinery, the biochemistry of SUMOylation and de-SUMOylation is relatively modest. Specificity of the SUMO pathway is achieved through redox regulation, acetylation, phosphorylation, or other posttranslational protein modification of the SUMOylation and de-SUMOylation enzymes. There are three major SUMOs. SUMO-1 usually modifies a substrate as a monomer; however, SUMO-2/3 can form poly-SUMO chains. The monomeric SUMO-1 or poly-SUMO chains can interact with other proteins through SUMO-interactive motif (SIM). Thus SUMO modification provides a platform to enhance protein-protein interaction. The consequence of SUMOylation includes changes in cellular localization, protein activity, or protein stability. Furthermore, SUMO may join force with ubiquitin to degrade proteins through SUMO-targeted ubiquitin ligases (STUbL). After 20 yr of research, SUMO has been shown to play critical roles in most, if not all, biological pathways. Thus the SUMO enzymes could be targets for drug development to treat human diseases.
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Affiliation(s)
- Hui-Ming Chang
- Center for Precision Medicine, Department of Medicine, University of Missouri, Columbia, Missouri
| | - Edward T H Yeh
- Center for Precision Medicine, Department of Medicine, University of Missouri, Columbia, Missouri
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SUMOylation of Enzymes and Ion Channels in Sensory Neurons Protects against Metabolic Dysfunction, Neuropathy, and Sensory Loss in Diabetes. Neuron 2020; 107:1141-1159.e7. [PMID: 32735781 DOI: 10.1016/j.neuron.2020.06.037] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2019] [Revised: 04/20/2020] [Accepted: 06/26/2020] [Indexed: 12/31/2022]
Abstract
Diabetic peripheral neuropathy (DPN) is a highly frequent and debilitating clinical complication of diabetes that lacks therapies. Cellular oxidative stress regulates post-translational modifications, including SUMOylation. Here, using unbiased screens, we identified key enzymes in metabolic pathways and ion channels as novel molecular targets of SUMOylation that critically regulated their activity. Sensory neurons of diabetic patients and diabetic mice demonstrated changes in the SUMOylation status of metabolic enzymes and ion channels. In support of this, profound metabolic dysfunction, accelerated neuropathology, and sensory loss were observed in diabetic gene-targeted mice selectively lacking the ability to SUMOylate proteins in peripheral sensory neurons. TRPV1 function was impaired by diabetes-induced de-SUMOylation as well as by metabolic imbalance elicited by de-SUMOylation of metabolic enzymes, facilitating diabetic sensory loss. Our results unexpectedly uncover an endogenous post-translational mechanism regulating diabetic neuropathy in patients and mouse models that protects against metabolic dysfunction, nerve damage, and altered sensory perception.
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Li N, Zhang S, Xiong F, Eizirik DL, Wang CY. SUMOylation, a multifaceted regulatory mechanism in the pancreatic beta cells. Semin Cell Dev Biol 2020; 103:51-58. [PMID: 32331991 DOI: 10.1016/j.semcdb.2020.03.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2019] [Revised: 01/03/2020] [Accepted: 03/23/2020] [Indexed: 12/19/2022]
Abstract
SUMOylation is an evolutionarily conserved post-translational modification (PTM) that regulates protein subcellular localization, stability, conformation, transcription and enzymatic activity. Recent studies indicate that SUMOylation plays a key role in insulin gene expression, glucose metabolism and insulin exocytosis under physiological conditions in the pancreatic beta cells. Furthermore, SUMOylation is implicated in beta cell survival and recovery following exposure to oxidative stress, ER stress and inflammatory mediators under pathological situations. SUMOylation is closely regulated by the cellular redox status, and it collaborates with other PTMs such as phosphorylation, ubiquitination, and NEDDylation, to maintain beta cellular homeostasis. We hereby provide an update on recent findings regarding the role of SUMOylation in the regulation of pancreatic beta cell viability and function, and discuss its potential implication in beta cell senescence and RNA processing (e.g., pre-mRNA splicing and mRNA methylation). Through which we intend to provide novel insights into this fundamental biological process regarding both maintenance of beta cell viability and functionality, and beta cell dysfunction in diabetes mellitus.
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Affiliation(s)
- Na Li
- The Center for Biomedical Research, Key Laboratory of Organ Transplantation, Ministry of Education, NHC Key Laboratory of Organ Transplantation, Key Laboratory of Organ Transplantation, Chinese Academy of Medical Sciences, Tongji Hospital, Wuhan, China
| | - Shu Zhang
- The Center for Biomedical Research, Key Laboratory of Organ Transplantation, Ministry of Education, NHC Key Laboratory of Organ Transplantation, Key Laboratory of Organ Transplantation, Chinese Academy of Medical Sciences, Tongji Hospital, Wuhan, China
| | - Fei Xiong
- The Center for Biomedical Research, Key Laboratory of Organ Transplantation, Ministry of Education, NHC Key Laboratory of Organ Transplantation, Key Laboratory of Organ Transplantation, Chinese Academy of Medical Sciences, Tongji Hospital, Wuhan, China
| | - Decio L Eizirik
- ULB Center for Diabetes Research, Université Libre de Bruxelles, 808 Route de Lennik, B-1070, Brussels, Belgium; Indiana Biosciences Research Institute (IBRI), Indianapolis, IN, USA.
| | - Cong-Yi Wang
- The Center for Biomedical Research, Key Laboratory of Organ Transplantation, Ministry of Education, NHC Key Laboratory of Organ Transplantation, Key Laboratory of Organ Transplantation, Chinese Academy of Medical Sciences, Tongji Hospital, Wuhan, China.
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Ferdaoussi M, Smith N, Lin H, Bautista A, Spigelman AF, Lyon J, Dai X, Manning Fox JE, MacDonald PE. Improved glucose tolerance with DPPIV inhibition requires β-cell SENP1 amplification of glucose-stimulated insulin secretion. Physiol Rep 2020; 8:e14420. [PMID: 32339440 PMCID: PMC7185381 DOI: 10.14814/phy2.14420] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Revised: 03/19/2020] [Accepted: 03/20/2020] [Indexed: 01/09/2023] Open
Abstract
Pancreatic islet insulin secretion is amplified by both metabolic and receptor-mediated signaling pathways. The incretin-mimetic and DPPIV inhibitor anti-diabetic drugs increase insulin secretion, but in humans this can be variable both in vitro and in vivo. We examined the correlation of GLP-1 induced insulin secretion from human islets with key donor characteristics, glucose-responsiveness, and the ability of glucose to augment exocytosis in β-cells. No clear correlation was observed between several donor or organ processing parameters and the ability of Exendin 4 to enhance insulin secretion. The ability of glucose to facilitate β-cell exocytosis was, however, significantly correlated with responses to Exendin 4. We therefore studied the effect of impaired glucose-dependent amplification of insulin exocytosis on responses to DPPIV inhibition (MK-0626) in vivo using pancreas and β-cell specific sentrin-specific protease-1 (SENP1) mice which exhibit impaired metabolic amplification of insulin exocytosis. Glucose tolerance was improved, and plasma insulin was increased, following either acute or 4 week treatment of wild-type (βSENP1+/+ ) mice with MK-0626. This DPPIV inhibitor was ineffective in βSENP1+/- or βSENP1- / - mice. Finally, we confirm impaired exocytotic responses of β-cells and reduced insulin secretion from islets of βSENP1- / - mice and show that the ability of Exendin 4 to enhance exocytosis is lost in these cells. Thus, an impaired ability of glucose to amplify insulin exocytosis results in a deficient effect of DPPIV inhibition to improve in vivo insulin responses and glucose tolerance.
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Affiliation(s)
- Mourad Ferdaoussi
- Department of Pharmacology and Alberta Diabetes InstituteUniversity of AlbertaEdmontonABCanada
| | - Nancy Smith
- Department of Pharmacology and Alberta Diabetes InstituteUniversity of AlbertaEdmontonABCanada
| | - Haopeng Lin
- Department of Pharmacology and Alberta Diabetes InstituteUniversity of AlbertaEdmontonABCanada
| | - Austin Bautista
- Department of Pharmacology and Alberta Diabetes InstituteUniversity of AlbertaEdmontonABCanada
| | - Aliya F. Spigelman
- Department of Pharmacology and Alberta Diabetes InstituteUniversity of AlbertaEdmontonABCanada
| | - James Lyon
- Department of Pharmacology and Alberta Diabetes InstituteUniversity of AlbertaEdmontonABCanada
| | - XiaoQing Dai
- Department of Pharmacology and Alberta Diabetes InstituteUniversity of AlbertaEdmontonABCanada
| | - Jocelyn E. Manning Fox
- Department of Pharmacology and Alberta Diabetes InstituteUniversity of AlbertaEdmontonABCanada
| | - Patrick E. MacDonald
- Department of Pharmacology and Alberta Diabetes InstituteUniversity of AlbertaEdmontonABCanada
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Fu J, Githaka JM, Dai X, Plummer G, Suzuki K, Spigelman AF, Bautista A, Kim R, Greitzer-Antes D, Fox JEM, Gaisano HY, MacDonald PE. A glucose-dependent spatial patterning of exocytosis in human β-cells is disrupted in type 2 diabetes. JCI Insight 2019; 5:127896. [PMID: 31085831 DOI: 10.1172/jci.insight.127896] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Impaired insulin secretion in type 2 diabetes (T2D) is linked to reduced insulin granule docking, disorganization of the exocytotic site, and an impaired glucose-dependent facilitation of insulin exocytosis. We show in β-cells from 80 human donors that the glucose-dependent amplification of exocytosis is disrupted in T2D. Spatial analyses of granule fusion, visualized by total internal reflection fluorescence (TIRF) microscopy in 24 of these donors, demonstrate that these are non-random across the surface of β-cells from donors with no diabetes (ND). The compartmentalization of events occurs within regions defined by concurrent or recent membrane-resident secretory granules. This organization, and the number of membrane-associated granules, is glucose-dependent and notably impaired in T2D β-cells. Mechanistically, multi-channel Kv2.1 clusters contribute to maintaining the density of membrane-resident granules and the number of fusion 'hotspots', while SUMOylation sites at the channel N- (K145) and C-terminus (K470) determine the relative proportion of fusion events occurring within these regions. Thus, a glucose-dependent compartmentalization of fusion, regulated in part by a structural role for Kv2.1, is disrupted in β-cells from donors with type 2 diabetes.
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Affiliation(s)
- Jianyang Fu
- Alberta Diabetes Institute and Department of Pharmacology and
| | | | - Xiaoqing Dai
- Alberta Diabetes Institute and Department of Pharmacology and
| | - Gregory Plummer
- Alberta Diabetes Institute and Department of Pharmacology and
| | - Kunimasa Suzuki
- Alberta Diabetes Institute and Department of Pharmacology and
| | | | - Austin Bautista
- Alberta Diabetes Institute and Department of Pharmacology and
| | - Ryekjang Kim
- Alberta Diabetes Institute and Department of Pharmacology and
| | - Dafna Greitzer-Antes
- Departments of Medicine and Physiology, University of Toronto, Toronto, Ontario, Canada
| | | | - Herbert Y Gaisano
- Departments of Medicine and Physiology, University of Toronto, Toronto, Ontario, Canada
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Davey JS, Carmichael RE, Craig TJ. Protein SUMOylation regulates insulin secretion at multiple stages. Sci Rep 2019; 9:2895. [PMID: 30814610 PMCID: PMC6393506 DOI: 10.1038/s41598-019-39681-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Accepted: 01/21/2019] [Indexed: 01/24/2023] Open
Abstract
Type-II Diabetes Mellitus (T2DM) is one of the fastest growing public health issues of modern times, consuming 12% of worldwide health budgets and affecting an estimated 400 million people. A key pathological trait associated with this disease is the failure of normal glucose-stimulated insulin secretion (GSIS) from pancreatic beta cells. Several lines of evidence suggest that vesicle trafficking events such as insulin secretion are regulated by the post-translational modification, SUMOylation, and indeed SUMOylation has been proposed to act as a ‘brake’ on insulin exocytosis. Here, we show that diabetic stimuli which inhibit GSIS are correlated with an increase in cellular protein SUMOylation, and that inhibition of deSUMOylation reduces GSIS. We demonstrate that manipulation of cellular protein SUMOylation levels, by overexpression of several different components of the SUMOylation pathway, have varied and complex effects on GSIS, indicating that SUMOylation regulates this process at multiple stages. We further demonstrate that inhibition of syntaxin1A SUMOylation, via a knockdown-rescue strategy, greatly enhances GSIS. Our data are therefore consistent with the model that SUMOylation acts as a brake on GSIS, and we have identified SUMOylation of syntaxin 1 A as a potential component of this brake. However, our data also demonstrate that the role of SUMOylation in GSIS is complex and may involve many substrates.
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Affiliation(s)
- Jeffrey S Davey
- Centre for Research in Biosciences, University of the West of England, Coldharbour Lane, Frenchay, Bristol, BS16 1QY, UK
| | - Ruth E Carmichael
- College of Life and Environmental Sciences, Geoffrey Pope Building, University of Exeter, Stocker Road, Exeter, EX4 4QD, UK
| | - Tim J Craig
- Centre for Research in Biosciences, University of the West of England, Coldharbour Lane, Frenchay, Bristol, BS16 1QY, UK.
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26
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Sternisha SM, Miller BG. Molecular and cellular regulation of human glucokinase. Arch Biochem Biophys 2019; 663:199-213. [PMID: 30641049 DOI: 10.1016/j.abb.2019.01.011] [Citation(s) in RCA: 73] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Revised: 01/09/2019] [Accepted: 01/10/2019] [Indexed: 01/23/2023]
Abstract
Glucose metabolism in humans is tightly controlled by the activity of glucokinase (GCK). GCK is predominantly produced in the pancreas, where it catalyzes the rate-limiting step of insulin secretion, and in the liver, where it participates in glycogen synthesis. A multitude of disease-causing mutations within the gck gene have been identified. Activating mutations manifest themselves in the clinic as congenital hyperinsulinism, while loss-of-function mutations produce several diabetic conditions. Indeed, pharmaceutical companies have shown great interest in developing GCK-associated treatments for diabetic patients. Due to its essential role in maintaining whole-body glucose homeostasis, GCK activity is extensively regulated at multiple levels. GCK possesses a unique ability to self-regulate its own activity via slow conformational dynamics, which allows for a cooperative response to glucose. GCK is also subject to a number of protein-protein interactions and post-translational modification events that produce a broad range of physiological consequences. While significant advances in our understanding of these individual regulatory mechanisms have been recently achieved, how these strategies are integrated and coordinated within the cell is less clear. This review serves to synthesize the relevant findings and offer insights into the connections between molecular and cellular control of GCK.
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Affiliation(s)
- Shawn M Sternisha
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL, 32306, USA
| | - Brian G Miller
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL, 32306, USA.
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27
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Stankovic-Valentin N, Melchior F. Control of SUMO and Ubiquitin by ROS: Signaling and disease implications. Mol Aspects Med 2018; 63:3-17. [PMID: 30059710 DOI: 10.1016/j.mam.2018.07.002] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Revised: 05/23/2018] [Accepted: 07/27/2018] [Indexed: 01/06/2023]
Abstract
Reversible post-translational modifications (PTMs) ensure rapid signal transmission from sensors to effectors. Reversible modification of proteins by the small proteins Ubiquitin and SUMO are involved in virtually all cellular processes and can modify thousands of proteins. Ubiquitination or SUMOylation is the reversible attachment of these modifiers to lysine residues of a target via isopeptide bond formation. These modifications require ATP and an enzymatic cascade composed of three classes of proteins: E1 activating enzymes, E2 conjugating enzymes and E3 ligases. The reversibility of the modification is ensured by specific isopeptidases. E1 and E2 enzymes, some E3 ligases and most isopeptidases have catalytic cysteine residues, which make them potentially susceptible for oxidation. Indeed, an increasing number of examples reveal regulation of ubiquitination and SUMOylation by reactive oxygen species, both in the context of redox signaling and in severe oxidative stress. Importantly, ubiquitination and SUMOylation play essential roles in the regulation of ROS homeostasis, participating in the control of ROS production and clearance. In this review, we will discuss the interplay between ROS homeostasis, Ubiquitin and SUMO pathways and the implications for the oxidative stress response and cell signaling.
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Affiliation(s)
- Nicolas Stankovic-Valentin
- Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), DKFZ - ZMBH Alliance, Heidelberg, Germany.
| | - Frauke Melchior
- Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), DKFZ - ZMBH Alliance, Heidelberg, Germany.
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28
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He X, Lai Q, Chen C, Li N, Sun F, Huang W, Zhang S, Yu Q, Yang P, Xiong F, Chen Z, Gong Q, Ren B, Weng J, Eizirik DL, Zhou Z, Wang CY. Both conditional ablation and overexpression of E2 SUMO-conjugating enzyme (UBC9) in mouse pancreatic beta cells result in impaired beta cell function. Diabetologia 2018; 61:881-895. [PMID: 29299635 DOI: 10.1007/s00125-017-4523-9] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 11/16/2017] [Indexed: 12/30/2022]
Abstract
AIMS/HYPOTHESIS Post-translational attachment of a small ubiquitin-like modifier (SUMO) to the lysine (K) residue(s) of target proteins (SUMOylation) is an evolutionary conserved regulatory mechanism. This modification has previously been demonstrated to be implicated in the control of a remarkably versatile regulatory mechanism of cellular processes. However, the exact regulatory role and biological actions of the E2 SUMO-conjugating enzyme (UBC9)-mediated SUMOylation function in pancreatic beta cells has remained elusive. METHODS Inducible beta cell-specific Ubc9 (also known as Ube2i) knockout (KO; Ubc9Δbeta) and transgenic (Ubc9Tg) mice were employed to address the impact of SUMOylation on beta cell viability and functionality. Ubc9 deficiency or overexpression was induced at 8 weeks of age using tamoxifen. To study the mechanism involved, we closely examined the regulation of the transcription factor nuclear factor erythroid 2-related factor 2 (NRF2) through SUMOylation in beta cells. RESULTS Upon induction of Ubc9 deficiency, Ubc9Δbeta islets exhibited a 3.5-fold higher accumulation of reactive oxygen species (ROS) than Ubc9f/f control islets. Islets from Ubc9Δbeta mice also had decreased insulin content and loss of beta cell mass after tamoxifen treatment. Specifically, at day 45 after Ubc9 deletion only 40% of beta cell mass remained in Ubc9Δbeta mice, while 90% of beta cell mass was lost by day 75. Diabetes onset was noted in some Ubc9Δbeta mice 8 weeks after induction of Ubc9 deficiency and all mice developed diabetes by 10 weeks following tamoxifen treatment. In contrast, Ubc9Tg beta cells displayed an increased antioxidant ability but impaired insulin secretion. Unlike Ubc9Δbeta mice, which spontaneously developed diabetes, Ubc9Tg mice preserved normal non-fasting blood glucose levels without developing diabetes. It was noted that SUMOylation of NRF2 promoted its nuclear expression along with enhanced transcriptional activity, thereby preventing ROS accumulation in beta cells. CONCLUSIONS/INTERPRETATION SUMOylation function is required to protect against oxidative stress in beta cells; this mechanism is, at least in part, carried out by the regulation of NRF2 activity to enhance ROS detoxification. Homeostatic SUMOylation is also likely to be essential for maintaining beta cell functionality.
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Affiliation(s)
- Xiaoyu He
- The Center for Biomedical Research, Key Laboratory of Organ Transplantation, Ministry of Education and Ministry of Health, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Avenue, Wuhan, 430030, People's Republic of China
| | - Qiaohong Lai
- The Center for Biomedical Research, Key Laboratory of Organ Transplantation, Ministry of Education and Ministry of Health, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Avenue, Wuhan, 430030, People's Republic of China
| | - Cai Chen
- The Center for Biomedical Research, Key Laboratory of Organ Transplantation, Ministry of Education and Ministry of Health, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Avenue, Wuhan, 430030, People's Republic of China
| | - Na Li
- The Center for Biomedical Research, Key Laboratory of Organ Transplantation, Ministry of Education and Ministry of Health, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Avenue, Wuhan, 430030, People's Republic of China
| | - Fei Sun
- The Center for Biomedical Research, Key Laboratory of Organ Transplantation, Ministry of Education and Ministry of Health, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Avenue, Wuhan, 430030, People's Republic of China
| | - Wenting Huang
- The Center for Biomedical Research, Key Laboratory of Organ Transplantation, Ministry of Education and Ministry of Health, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Avenue, Wuhan, 430030, People's Republic of China
| | - Shu Zhang
- The Center for Biomedical Research, Key Laboratory of Organ Transplantation, Ministry of Education and Ministry of Health, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Avenue, Wuhan, 430030, People's Republic of China
| | - Qilin Yu
- The Center for Biomedical Research, Key Laboratory of Organ Transplantation, Ministry of Education and Ministry of Health, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Avenue, Wuhan, 430030, People's Republic of China
| | - Ping Yang
- The Center for Biomedical Research, Key Laboratory of Organ Transplantation, Ministry of Education and Ministry of Health, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Avenue, Wuhan, 430030, People's Republic of China
| | - Fei Xiong
- The Center for Biomedical Research, Key Laboratory of Organ Transplantation, Ministry of Education and Ministry of Health, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Avenue, Wuhan, 430030, People's Republic of China
| | - Zhishui Chen
- The Center for Biomedical Research, Key Laboratory of Organ Transplantation, Ministry of Education and Ministry of Health, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Avenue, Wuhan, 430030, People's Republic of China
| | - Quan Gong
- Medical College of Yangtze University, Jingzhou, Hubei, People's Republic of China
| | - Boxu Ren
- Medical College of Yangtze University, Jingzhou, Hubei, People's Republic of China
| | - Jianping Weng
- Department of Endocrinology and Metabolism, The Third Affiliated Hospital, Sun Yat-Sen University, Guangzhou, People's Republic of China
| | - Décio L Eizirik
- ULB Center for Diabetes Research, Université Libre de Bruxelles, Brussels, Belgium
| | - Zhiguang Zhou
- Diabetes Center, The Second Xiangya Hospital, Institute of Metabolism and Endocrinology, Central South University, Changsha, 410011, People's Republic of China.
| | - Cong-Yi Wang
- The Center for Biomedical Research, Key Laboratory of Organ Transplantation, Ministry of Education and Ministry of Health, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Avenue, Wuhan, 430030, People's Republic of China.
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MacDonald PE. A post-translational balancing act: the good and the bad of SUMOylation in pancreatic islets. Diabetologia 2018; 61:775-779. [PMID: 29330559 DOI: 10.1007/s00125-017-4543-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Accepted: 12/20/2017] [Indexed: 12/18/2022]
Abstract
Post-translational modification of proteins contributes to the control of cell function and survival. The balance of these in insulin-producing pancreatic beta cells is important for the maintenance of glucose homeostasis. Protection from the damaging effects of reactive oxygen species is required for beta cell survival, but if this happens at the expense of insulin secretory function then the ability of islets to respond to changing metabolic conditions may be compromised. In this issue of Diabetologia, He et al ( https://doi.org/10.1007/s00125-017-4523-9 ) show that post-translational attachment of small ubiquitin-like modifier (SUMO) to target lysine residues (SUMOylation) strikes an important balance between the protection of beta cells from oxidative stress and the maintenance of insulin secretory function. They show that SUMOylation is required to stabilise nuclear factor erythroid 2-related factor 2 (NRF2) and increase antioxidant gene expression. Decreasing SUMOylation in beta cells impairs their antioxidant capacity, causes cell death, hyperglycaemia, and increased sensitivity to streptozotocin-induced diabetes, while increasing SUMOylation is protective. However, this protection from overt diabetes occurs in concert with glucose intolerance due to impaired beta cell function. A possible role for SUMOylation as a key factor balancing beta cell protection vs beta cell responsiveness to metabolic cues is discussed in this Commentary.
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Affiliation(s)
- Patrick E MacDonald
- Department of Pharmacology, University of Alberta, Edmonton, AB, Canada.
- Alberta Diabetes Institute, LKS Centre, Rm. 6-126, University of Alberta, Edmonton, AB, T6G 2E1, Canada.
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30
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Pandey D, Nomura Y, Rossberg MC, Hori D, Bhatta A, Keceli G, Leucker T, Santhanam L, Shimoda LA, Berkowitz D, Romer L. Hypoxia Triggers SENP1 (Sentrin-Specific Protease 1) Modulation of KLF15 (Kruppel-Like Factor 15) and Transcriptional Regulation of Arg2 (Arginase 2) in Pulmonary Endothelium. Arterioscler Thromb Vasc Biol 2018; 38:913-926. [PMID: 29472234 DOI: 10.1161/atvbaha.117.310660] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Accepted: 02/06/2018] [Indexed: 02/07/2023]
Abstract
OBJECTIVE KLF15 (Kruppel-like factor 15) has recently been shown to suppress activation of proinflammatory processes that contribute to atherogenesis in vascular smooth muscle, however, the role of KLF15 in vascular endothelial function is unknown. Arginase mediates inflammatory vasculopathy and vascular injury in pulmonary hypertension. Here, we tested the hypothesis that KLF15 is a critical regulator of hypoxia-induced Arg2 (arginase 2) transcription in human pulmonary microvascular endothelial cells (HPMEC). APPROACH AND RESULTS Quiescent HPMEC express ample amounts of full-length KLF15. HPMECs exposed to 24 hours of hypoxia exhibited a marked decrease in KLF15 protein levels and a reciprocal increase in Arg2 protein and mRNA. Chromatin immunoprecipitation indicated direct binding of KLF15 to the Arg2 promoter, which was relieved with HPMEC exposure to hypoxia. Furthermore, overexpression of KLF15 in HPMEC reversed hypoxia-induced augmentation of Arg2 abundance and arginase activity and rescued nitric oxide (NO) production. Ectopic KLF15 also reversed hypoxia-induced endothelium-mediated vasodilatation in isolated rat pulmonary artery rings. Mechanisms by which hypoxia regulates KLF15 abundance, stability, and compartmentalization to the nucleus in HPMEC were then investigated. Hypoxia triggered deSUMOylation of KLF15 by SENP1 (sentrin-specific protease 1), and translocation of KLF15 from nucleus to cytoplasm. CONCLUSIONS KLF15 is a critical regulator of pulmonary endothelial homeostasis via repression of endothelial Arg2 expression. KLF15 abundance and nuclear compartmentalization are regulated by SUMOylation/deSUMOylation-a hypoxia-sensitive process that is controlled by SENP1. Strategies including overexpression of KLF15 or inhibition of SENP1 may represent novel therapeutic targets for pulmonary hypertension.
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Affiliation(s)
- Deepesh Pandey
- From the Departments of Anesthesiology and Critical Care Medicine (D.P., Y.N., M.C.R., D.H., A.B., L.S., D.B., L.R.), Cell Biology (L.R.), Biomedical Engineering (D.B., L.R.), and Pediatrics, and the Center for Cell Dynamics (L.R.), Division of Cardiology (G.K., T.L.), and Division of Pulmonary and Critical Care Medicine, Department of Medicine (L.A.S.), Johns Hopkins Medical Institutions, Baltimore, MD.
| | - Yohei Nomura
- From the Departments of Anesthesiology and Critical Care Medicine (D.P., Y.N., M.C.R., D.H., A.B., L.S., D.B., L.R.), Cell Biology (L.R.), Biomedical Engineering (D.B., L.R.), and Pediatrics, and the Center for Cell Dynamics (L.R.), Division of Cardiology (G.K., T.L.), and Division of Pulmonary and Critical Care Medicine, Department of Medicine (L.A.S.), Johns Hopkins Medical Institutions, Baltimore, MD
| | - Max C Rossberg
- From the Departments of Anesthesiology and Critical Care Medicine (D.P., Y.N., M.C.R., D.H., A.B., L.S., D.B., L.R.), Cell Biology (L.R.), Biomedical Engineering (D.B., L.R.), and Pediatrics, and the Center for Cell Dynamics (L.R.), Division of Cardiology (G.K., T.L.), and Division of Pulmonary and Critical Care Medicine, Department of Medicine (L.A.S.), Johns Hopkins Medical Institutions, Baltimore, MD
| | - Daijiro Hori
- From the Departments of Anesthesiology and Critical Care Medicine (D.P., Y.N., M.C.R., D.H., A.B., L.S., D.B., L.R.), Cell Biology (L.R.), Biomedical Engineering (D.B., L.R.), and Pediatrics, and the Center for Cell Dynamics (L.R.), Division of Cardiology (G.K., T.L.), and Division of Pulmonary and Critical Care Medicine, Department of Medicine (L.A.S.), Johns Hopkins Medical Institutions, Baltimore, MD
| | - Anil Bhatta
- From the Departments of Anesthesiology and Critical Care Medicine (D.P., Y.N., M.C.R., D.H., A.B., L.S., D.B., L.R.), Cell Biology (L.R.), Biomedical Engineering (D.B., L.R.), and Pediatrics, and the Center for Cell Dynamics (L.R.), Division of Cardiology (G.K., T.L.), and Division of Pulmonary and Critical Care Medicine, Department of Medicine (L.A.S.), Johns Hopkins Medical Institutions, Baltimore, MD
| | - Gizem Keceli
- From the Departments of Anesthesiology and Critical Care Medicine (D.P., Y.N., M.C.R., D.H., A.B., L.S., D.B., L.R.), Cell Biology (L.R.), Biomedical Engineering (D.B., L.R.), and Pediatrics, and the Center for Cell Dynamics (L.R.), Division of Cardiology (G.K., T.L.), and Division of Pulmonary and Critical Care Medicine, Department of Medicine (L.A.S.), Johns Hopkins Medical Institutions, Baltimore, MD
| | - Thorsten Leucker
- From the Departments of Anesthesiology and Critical Care Medicine (D.P., Y.N., M.C.R., D.H., A.B., L.S., D.B., L.R.), Cell Biology (L.R.), Biomedical Engineering (D.B., L.R.), and Pediatrics, and the Center for Cell Dynamics (L.R.), Division of Cardiology (G.K., T.L.), and Division of Pulmonary and Critical Care Medicine, Department of Medicine (L.A.S.), Johns Hopkins Medical Institutions, Baltimore, MD
| | - Lakshmi Santhanam
- From the Departments of Anesthesiology and Critical Care Medicine (D.P., Y.N., M.C.R., D.H., A.B., L.S., D.B., L.R.), Cell Biology (L.R.), Biomedical Engineering (D.B., L.R.), and Pediatrics, and the Center for Cell Dynamics (L.R.), Division of Cardiology (G.K., T.L.), and Division of Pulmonary and Critical Care Medicine, Department of Medicine (L.A.S.), Johns Hopkins Medical Institutions, Baltimore, MD
| | - Larissa A Shimoda
- From the Departments of Anesthesiology and Critical Care Medicine (D.P., Y.N., M.C.R., D.H., A.B., L.S., D.B., L.R.), Cell Biology (L.R.), Biomedical Engineering (D.B., L.R.), and Pediatrics, and the Center for Cell Dynamics (L.R.), Division of Cardiology (G.K., T.L.), and Division of Pulmonary and Critical Care Medicine, Department of Medicine (L.A.S.), Johns Hopkins Medical Institutions, Baltimore, MD
| | - Dan Berkowitz
- From the Departments of Anesthesiology and Critical Care Medicine (D.P., Y.N., M.C.R., D.H., A.B., L.S., D.B., L.R.), Cell Biology (L.R.), Biomedical Engineering (D.B., L.R.), and Pediatrics, and the Center for Cell Dynamics (L.R.), Division of Cardiology (G.K., T.L.), and Division of Pulmonary and Critical Care Medicine, Department of Medicine (L.A.S.), Johns Hopkins Medical Institutions, Baltimore, MD
| | - Lewis Romer
- From the Departments of Anesthesiology and Critical Care Medicine (D.P., Y.N., M.C.R., D.H., A.B., L.S., D.B., L.R.), Cell Biology (L.R.), Biomedical Engineering (D.B., L.R.), and Pediatrics, and the Center for Cell Dynamics (L.R.), Division of Cardiology (G.K., T.L.), and Division of Pulmonary and Critical Care Medicine, Department of Medicine (L.A.S.), Johns Hopkins Medical Institutions, Baltimore, MD
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Parker Gaddis K, Megonigal J, Clay J, Wolfe C. Genome-wide association study for ketosis in US Jerseys using producer-recorded data. J Dairy Sci 2018; 101:413-424. [DOI: 10.3168/jds.2017-13383] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Accepted: 09/16/2017] [Indexed: 12/20/2022]
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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: 456] [Impact Index Per Article: 76.0] [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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Hastoy B, Clark A, Rorsman P, Lang J. Fusion pore in exocytosis: More than an exit gate? A β-cell perspective. Cell Calcium 2017; 68:45-61. [PMID: 29129207 DOI: 10.1016/j.ceca.2017.10.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Revised: 10/17/2017] [Accepted: 10/24/2017] [Indexed: 12/14/2022]
Abstract
Secretory vesicle exocytosis is a fundamental biological event and the process by which hormones (like insulin) are released into the blood. Considerable progress has been made in understanding this precisely orchestrated sequence of events from secretory vesicle docked at the cell membrane, hemifusion, to the opening of a membrane fusion pore. The exact biophysical and physiological regulation of these events implies a close interaction between membrane proteins and lipids in a confined space and constrained geometry to ensure appropriate delivery of cargo. We consider some of the still open questions such as the nature of the initiation of the fusion pore, the structure and the role of the Soluble N-ethylmaleimide-sensitive-factor Attachment protein REceptor (SNARE) transmembrane domains and their influence on the dynamics and regulation of exocytosis. We discuss how the membrane composition and protein-lipid interactions influence the likelihood of the nascent fusion pore forming. We relate these factors to the hypothesis that fusion pore expansion could be affected in type-2 diabetes via changes in disease-related gene transcription and alterations in the circulating lipid profile. Detailed characterisation of the dynamics of the fusion pore in vitro will contribute to understanding the larger issue of insulin secretory defects in diabetes.
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Affiliation(s)
- Benoit Hastoy
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford OX3 7LE, UK.
| | - Anne Clark
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford OX3 7LE, UK
| | - Patrik Rorsman
- Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford OX3 7LE, UK; Metabolic Research, Institute of Neuroscience and Physiology, University of Goteborg, Medicinaregatan 11, S-41309 Göteborg, Sweden
| | - Jochen Lang
- Laboratoire de Chimie et Biologie des Membranes et Nano-objets (CBMN), CNRS UMR 5248, Université de Bordeaux, Allée de Geoffrey St Hilaire, 33600 Pessac, France.
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Bozadjieva N, Blandino-Rosano M, Chase J, Dai XQ, Cummings K, Gimeno J, Dean D, Powers AC, Gittes GK, Rüegg MA, Hall MN, MacDonald PE, Bernal-Mizrachi E. Loss of mTORC1 signaling alters pancreatic α cell mass and impairs glucagon secretion. J Clin Invest 2017; 127:4379-4393. [PMID: 29106387 DOI: 10.1172/jci90004] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Accepted: 09/26/2017] [Indexed: 01/19/2023] Open
Abstract
Glucagon plays a major role in the regulation of glucose homeostasis during fed and fasting states. However, the mechanisms responsible for the regulation of pancreatic α cell mass and function are not completely understood. In the current study, we identified mTOR complex 1 (mTORC1) as a major regulator of α cell mass and glucagon secretion. Using mice with tissue-specific deletion of the mTORC1 regulator Raptor in α cells (αRaptorKO), we showed that mTORC1 signaling is dispensable for α cell development, but essential for α cell maturation during the transition from a milk-based diet to a chow-based diet after weaning. Moreover, inhibition of mTORC1 signaling in αRaptorKO mice and in WT animals exposed to chronic rapamycin administration decreased glucagon content and glucagon secretion. In αRaptorKO mice, impaired glucagon secretion occurred in response to different secretagogues and was mediated by alterations in KATP channel subunit expression and activity. Additionally, our data identify the mTORC1/FoxA2 axis as a link between mTORC1 and transcriptional regulation of key genes responsible for α cell function. Thus, our results reveal a potential function of mTORC1 in nutrient-dependent regulation of glucagon secretion and identify a role for mTORC1 in controlling α cell-mass maintenance.
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Affiliation(s)
- Nadejda Bozadjieva
- Department of Internal Medicine, Division of Metabolism, Endocrinology and Diabetes, and.,Graduate Program in Cellular and Molecular Biology, University of Michigan, Ann Arbor, Michigan, USA
| | - Manuel Blandino-Rosano
- Department of Internal Medicine, Division of Metabolism, Endocrinology and Diabetes, and.,Department of Internal Medicine, Division Endocrinology, Metabolism and Diabetes, Miller School of Medicine, University of Miami, Miami, Florida, USA
| | - Jennifer Chase
- Graduate Program in Cellular and Molecular Biology, University of Michigan, Ann Arbor, Michigan, USA
| | - Xiao-Qing Dai
- Alberta Diabetes Institute and Department of Pharmacology, Edmonton, Alberta, Canada
| | - Kelsey Cummings
- Department of Internal Medicine, Division of Metabolism, Endocrinology and Diabetes, and
| | - Jennifer Gimeno
- Department of Internal Medicine, Division Endocrinology, Metabolism and Diabetes, Miller School of Medicine, University of Miami, Miami, Florida, USA
| | - Danielle Dean
- Department of Medicine, Division of Diabetes, Endocrinology, and Metabolism, and
| | - Alvin C Powers
- Department of Medicine, Division of Diabetes, Endocrinology, and Metabolism, and.,Department of Molecular Physiology & Biophysics, Vanderbilt University, Nashville, Tennessee, USA.,VA Tennessee Valley Healthcare, Nashville, Tennessee, USA
| | - George K Gittes
- Children's Hospital, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | | | | | - Patrick E MacDonald
- Alberta Diabetes Institute and Department of Pharmacology, Edmonton, Alberta, Canada
| | - Ernesto Bernal-Mizrachi
- Department of Internal Medicine, Division of Metabolism, Endocrinology and Diabetes, and.,Graduate Program in Cellular and Molecular Biology, University of Michigan, Ann Arbor, Michigan, USA.,Department of Internal Medicine, Division Endocrinology, Metabolism and Diabetes, Miller School of Medicine, University of Miami, Miami, Florida, USA.,Veterans Affairs Medical Center, Miami, Florida, USA
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Abstract
Protein modification with the small ubiquitin-related modifier (SUMO) can affect protein function, enzyme activity, protein-protein interactions, protein stability, protein targeting and cellular localization. SUMO influences the function and regulation of metabolic enzymes within pathways, and in some cases targets entire metabolic pathways by affecting the activity of transcription factors or by facilitating the translocation of entire metabolic pathways to subcellular compartments. SUMO modification is also a key component of nutrient- and metabolic-sensing mechanisms that regulate cellular metabolism. In addition to its established roles in maintaining metabolic homeostasis, there is increasing evidence that SUMO is a key factor in facilitating cellular stress responses through the regulation and/or adaptation of the most fundamental metabolic processes, including energy and nucleotide metabolism. This review focuses on the role of SUMO in cellular metabolism and metabolic disease.
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Jensen MV, Gooding J, Ferdaoussi M, Dai XQ, MacDonald PE, Newgard CB. Metabolomics applied to islet nutrient sensing mechanisms. Diabetes Obes Metab 2017; 19 Suppl 1:90-94. [PMID: 28880482 PMCID: PMC5929146 DOI: 10.1111/dom.13010] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Revised: 05/09/2017] [Accepted: 05/12/2017] [Indexed: 12/16/2022]
Abstract
After multiple decades of investigation, the precise mechanisms involved in fuel-stimulated insulin secretion are still being revealed. One avenue for gaining deeper knowledge is to apply emergent tools of "metabolomics," involving mass spectrometry and nuclear magnetic resonance-based profiling of islet cells in their fuel-stimulated compared with basal states. The current article summarizes recent insights gained from application of metabolomics tools to the specific process of glucose-stimulated insulin secretion, revealing 2 new mechanisms that may provide targets for improving insulin secretion in diabetes.
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Affiliation(s)
- Mette V. Jensen
- Sarah W. Stedman Nutrition and Metabolism Center, Duke Molecular Physiology Institute, Duke University Medical Center, Durham, NC 27701
| | - Jessica Gooding
- Sarah W. Stedman Nutrition and Metabolism Center, Duke Molecular Physiology Institute, Duke University Medical Center, Durham, NC 27701
| | - Mourad Ferdaoussi
- Department of Pharmacology and Alberta Diabetes Institute, University of Alberta, Edmonton, AB, Canada, T6G2R3
| | - Xiao-Qing Dai
- Department of Pharmacology and Alberta Diabetes Institute, University of Alberta, Edmonton, AB, Canada, T6G2R3
| | - Patrick E. MacDonald
- Department of Pharmacology and Alberta Diabetes Institute, University of Alberta, Edmonton, AB, Canada, T6G2R3
| | - Christopher B. Newgard
- Sarah W. Stedman Nutrition and Metabolism Center, Duke Molecular Physiology Institute, Duke University Medical Center, Durham, NC 27701
- Corresponding Author: Christopher B. Newgard, PhD, Duke Molecular Physiology Institute, 300 North Duke Street, Durham, NC 27701, , Phone: (919) 668-6059
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Abstract
Pancreatic islet β cells secrete insulin in response to nutrient secretagogues, like glucose, dependent on calcium influx and nutrient metabolism. One of the most intriguing qualities of β cells is their ability to use metabolism to amplify the amount of secreted insulin independent of further alterations in intracellular calcium. Many years studying this amplifying process have shaped our current understanding of β cell stimulus-secretion coupling; yet, the exact mechanisms of amplification have been elusive. Recent studies utilizing metabolomics, computational modeling, and animal models have progressed our understanding of the metabolic amplifying pathway of insulin secretion from the β cell. New approaches will be discussed which offer in-roads to a more complete model of β cell function. The development of β cell therapeutics may be aided by such a model, facilitating the targeting of aspects of the metabolic amplifying pathway which are unique to the β cell.
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Affiliation(s)
- Michael A Kalwat
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX, United States.
| | - Melanie H Cobb
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX, United States
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SUMOylation and calcium control syntaxin-1A and secretagogin sequestration by tomosyn to regulate insulin exocytosis in human ß cells. Sci Rep 2017; 7:248. [PMID: 28325894 PMCID: PMC5428262 DOI: 10.1038/s41598-017-00344-z] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Accepted: 02/22/2017] [Indexed: 11/09/2022] Open
Abstract
Insulin secretion from pancreatic ß cells is a multistep process that requires the coordination of exocytotic proteins that integrate diverse signals. These include signals derived from metabolic control of post-translational SUMOylation and depolarization-induced rises in intracellular Ca2+. Here we show that tomosyn, which suppresses insulin exocytosis by binding syntaxin1A, does so in a manner which requires its SUMOylation. Glucose-dependent de-SUMOylation of tomosyn1 at K298 releases syntaxin1A and controls the amplification of exocytosis in concert with a recently-identified tomosyn1-interacting partner; the Ca2+-binding protein secretagogin, which dissociates from tomosyn1 in response to Ca2+-raising stimuli and is required for insulin granule trafficking and exocytosis downstream of Ca2+ influx. Together our results suggest that tomosyn acts as a key signaling hub in insulin secretion by integrating signals mediated by metabolism-dependent de-SUMOylation and electrically-induced entry of Ca2+ to regulate the availability of exocytotic proteins required for the amplification of insulin secretion.
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Converting Adult Pancreatic Islet α Cells into β Cells by Targeting Both Dnmt1 and Arx. Cell Metab 2017; 25:622-634. [PMID: 28215845 PMCID: PMC5358097 DOI: 10.1016/j.cmet.2017.01.009] [Citation(s) in RCA: 153] [Impact Index Per Article: 21.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Revised: 10/21/2016] [Accepted: 01/17/2017] [Indexed: 02/06/2023]
Abstract
Insulin-producing pancreatic β cells in mice can slowly regenerate from glucagon-producing α cells in settings like β cell loss, but the basis of this conversion is unknown. Moreover, it remains unclear if this intra-islet cell conversion is relevant to diseases like type 1 diabetes (T1D). We show that the α cell regulators Aristaless-related homeobox (Arx) and DNA methyltransferase 1 (Dnmt1) maintain α cell identity in mice. Within 3 months of Dnmt1 and Arx loss, lineage tracing and single-cell RNA sequencing revealed extensive α cell conversion into progeny resembling native β cells. Physiological studies demonstrated that converted α cells acquire hallmark β cell electrophysiology and show glucose-stimulated insulin secretion. In T1D patients, subsets of glucagon-expressing cells show loss of DNMT1 and ARX and produce insulin and other β cell factors, suggesting that DNMT1 and ARX maintain α cell identity in humans. Our work reveals pathways regulated by Arx and Dnmt1 that are sufficient for achieving targeted generation of β cells from adult pancreatic α cells.
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40
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Schulze T, Morsi M, Reckers K, Brüning D, Seemann N, Panten U, Rustenbeck I. Metabolic amplification of insulin secretion is differentially desensitized by depolarization in the absence of exogenous fuels. Metabolism 2017; 67:1-13. [PMID: 28081772 DOI: 10.1016/j.metabol.2016.10.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Revised: 10/18/2016] [Accepted: 10/20/2016] [Indexed: 11/25/2022]
Abstract
OBJECTIVE The metabolic amplification of insulin secretion is the sequence of events which enables the secretory response to a fuel secretagogue to exceed the secretory response to a purely depolarizing stimulus. The signals in this pathway are incompletely understood. Here, we have characterized an experimental procedure by which the amplifying response to glucose is reversibly desensitized, while the response to α-ketoisocaproic acid (KIC) is unchanged. MATERIALS/METHODS Insulin secretion, NAD(P)H- and FAD-autofluorescence, Fura-2 fluorescence and oxygen consumption were measured in perifused NMRI mouse islets. The ATP- and ADP-contents were measured in statically incubated mouse islets. All islets were freshly isolated. RESULTS While the original observation on the dissociation between glucose- and KIC-amplification was obtained with islets that had been exposed to a high concentration of the sulfonylurea glipizide in the absence of glucose, we now show that in the absence of exogenous fuel a moderate depolarization, irrespective of its mechanism, progressively decreased the amplification in response to both glucose and KIC. However, the amplification in response to glucose declined faster, so a time window exists where glucose was already inefficient, whereas KIC was of unimpaired efficiency. Measurements of adenine nucleotides, NAD(P)H- and FAD-autofluorescence, and oxygen consumption point to a central role of the mitochondrial metabolism in this process. The desensitization could be quickly reversed by increasing oxidative deamination of glutamate and consequently anaplerosis of the citrate cycle. CONCLUSION Depolarization in the absence of exogenous fuel may be a useful model to identify those signals which are indispensable for the generation of metabolic amplification.
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Affiliation(s)
- Torben Schulze
- Institute of Pharmacology and Toxicology, University of Braunschweig, D-38106 Braunschweig, Germany
| | - Mai Morsi
- Institute of Pharmacology and Toxicology, University of Braunschweig, D-38106 Braunschweig, Germany
| | - Kirstin Reckers
- Institute of Pharmacology and Toxicology, University of Braunschweig, D-38106 Braunschweig, Germany
| | - Dennis Brüning
- Institute of Pharmacology and Toxicology, University of Braunschweig, D-38106 Braunschweig, Germany
| | - Nele Seemann
- Institute of Pharmacology and Toxicology, University of Braunschweig, D-38106 Braunschweig, Germany
| | - Uwe Panten
- Institute of Pharmacology and Toxicology, University of Braunschweig, D-38106 Braunschweig, Germany
| | - Ingo Rustenbeck
- Institute of Pharmacology and Toxicology, University of Braunschweig, D-38106 Braunschweig, Germany.
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Jayabalan N, Nair S, Nuzhat Z, Rice GE, Zuñiga FA, Sobrevia L, Leiva A, Sanhueza C, Gutiérrez JA, Lappas M, Freeman DJ, Salomon C. Cross Talk between Adipose Tissue and Placenta in Obese and Gestational Diabetes Mellitus Pregnancies via Exosomes. Front Endocrinol (Lausanne) 2017; 8:239. [PMID: 29021781 PMCID: PMC5623931 DOI: 10.3389/fendo.2017.00239] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Accepted: 08/30/2017] [Indexed: 12/16/2022] Open
Abstract
Obesity is an important public health issue worldwide, where it is commonly associated with the development of metabolic disorders, especially insulin resistance (IR). Maternal obesity is associated with an increased risk of pregnancy complications, especially gestational diabetes mellitus (GDM). Metabolism is a vital process for energy production and the maintenance of essential cellular functions. Excess energy storage is predominantly regulated by the adipose tissue. Primarily made up of adipocytes, adipose tissue acts as the body's major energy reservoir. The role of adipose tissue, however, is not restricted to a "bag of fat." The adipose tissue is an endocrine organ, secreting various adipokines, enzymes, growth factors, and hormones that take part in glucose and lipid metabolism. In obesity, the greater portion of the adipose tissue comprises fat, and there is increased pro-inflammatory cytokine secretion, macrophage infiltration, and reduced insulin sensitivity. Obesity contributes to systemic IR and its associated metabolic complications. Similar to adipose tissue, the placenta is also an endocrine organ. During pregnancy, the placenta secretes various molecules to maintain pregnancy physiology. In addition, the placenta plays an important role in metabolism and exchange of nutrients between mother and fetus. Inflammation at the placenta may contribute to the severity of maternal IR and her likelihood of developing GDM and may also mediate the adverse consequences of obesity and GDM on the fetus. Interestingly, studies on maternal insulin sensitivity and secretion of placental hormones have not shown a positive correlation between these phenomena. Recently, a great interest in the field of extracellular vesicles (EVs) has been observed in the literature. EVs are produced by a wide range of cells and are present in all biological fluids. EVs are involved in cell-to-cell communication. Recent evidence points to an association between adipose tissue-derived EVs and metabolic syndrome in obesity. In this review, we will discuss the changes in human placenta and adipose tissue in GDM and obesity and summarize the findings regarding the role of adipose tissue and placenta-derived EVs, with an emphasis on exosomes in obesity, and the contribution of obesity to the development of GDM.
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Affiliation(s)
- Nanthini Jayabalan
- Exosome Biology Laboratory, Centre for Clinical Diagnostics, University of Queensland Centre for Clinical Research, Royal Brisbane and Women’s Hospital, The University of Queensland, Brisbane, QLD, Australia
| | - Soumyalekshmi Nair
- Exosome Biology Laboratory, Centre for Clinical Diagnostics, University of Queensland Centre for Clinical Research, Royal Brisbane and Women’s Hospital, The University of Queensland, Brisbane, QLD, Australia
| | - Zarin Nuzhat
- Exosome Biology Laboratory, Centre for Clinical Diagnostics, University of Queensland Centre for Clinical Research, Royal Brisbane and Women’s Hospital, The University of Queensland, Brisbane, QLD, Australia
| | - Gregory E. Rice
- Exosome Biology Laboratory, Centre for Clinical Diagnostics, University of Queensland Centre for Clinical Research, Royal Brisbane and Women’s Hospital, The University of Queensland, Brisbane, QLD, Australia
- Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Ochsner Clinic Foundation, New Orleans, LA, United States
| | - Felipe A. Zuñiga
- Faculty of Pharmacy, Department of Clinical Biochemistry and Immunology, University of Concepción, Concepción, Chile
| | - Luis Sobrevia
- Cellular and Molecular Physiology Laboratory (CMPL), Division of Obstetrics and Gynaecology, Faculty of Medicine, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
- University of Queensland Centre for Clinical Research, Royal Brisbane and Women’s Hospital, The University of Queensland, Brisbane, QLD, Australia
- Faculty of Pharmacy, Department of Physiology, Universidad de Sevilla, Seville, Spain
| | - Andrea Leiva
- Cellular and Molecular Physiology Laboratory (CMPL), Division of Obstetrics and Gynaecology, Faculty of Medicine, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Carlos Sanhueza
- Cellular and Molecular Physiology Laboratory (CMPL), Division of Obstetrics and Gynaecology, Faculty of Medicine, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Jaime Agustín Gutiérrez
- Cellular Signaling and Differentiation Laboratory (CSDL), Medical Technology School, Health Sciences Faculty, Universidad San Sebastian, Santiago, Chile
- Cellular and Molecular Physiology Laboratory (CMPL), Division of Obstetrics and Gynaecology, Faculty of Medicine, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Martha Lappas
- Obstetrics, Nutrition and Endocrinology Group, Department of Obstetrics and Gynaecology, University of Melbourne, Melbourne, VIC, Australia
- Mercy Perinatal Research Centre, Mercy Hospital for Women, Heidelberg, VIC, Australia
| | - Dilys Jane Freeman
- Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Carlos Salomon
- Exosome Biology Laboratory, Centre for Clinical Diagnostics, University of Queensland Centre for Clinical Research, Royal Brisbane and Women’s Hospital, The University of Queensland, Brisbane, QLD, Australia
- Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Ochsner Clinic Foundation, New Orleans, LA, United States
- Faculty of Pharmacy, Department of Clinical Biochemistry and Immunology, University of Concepción, Concepción, Chile
- Mater Research Institute-University of Queensland, Translational Research Institute, Woolloongabba, QLD, Australia
- *Correspondence: Carlos Salomon,
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Ferdaoussi M, MacDonald PE. Toward Connecting Metabolism to the Exocytotic Site. Trends Cell Biol 2016; 27:163-171. [PMID: 27932063 DOI: 10.1016/j.tcb.2016.10.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Revised: 10/28/2016] [Accepted: 10/31/2016] [Indexed: 12/14/2022]
Abstract
Within cells the regulated exocytosis of secretory granules controls multiple physiological functions, including endocrine hormone secretion. Release of the glucose-regulating hormone insulin from pancreatic islet β cells is critical for whole-body metabolic homeostasis. Impaired insulin secretion appears early in the progression to type 2 diabetes (T2D). Key mechanisms that control the β-cell exocytotic response, mediating the long-known but little understood metabolic amplification of insulin secretion, are becoming clearer. Recent insights indicate a convergence of metabolism-driven signals, such as lipid-derived messengers and redox-dependent deSUMOylation, at the plasma membrane to augment Ca2+-dependent insulin exocytosis. These pathways have important implications for the metabolic control of hormone secretion, for the functional compensation that occurs in obesity, and for impaired insulin secretion in diabetes.
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Affiliation(s)
- Mourad Ferdaoussi
- Department of Pharmacology and Alberta Diabetes Institute, University of Alberta, Edmonton, AB, Canada T6G 2E1
| | - Patrick E MacDonald
- Department of Pharmacology and Alberta Diabetes Institute, University of Alberta, Edmonton, AB, Canada T6G 2E1.
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43
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Jung HS, Kang YM, Park HS, Ahn BY, Lee H, Kim MJ, Jang JY, Kim SW. Senp2 expression was induced by chronic glucose stimulation in INS1 cells, and it was required for the associated induction of Ccnd1 and Mafa. Islets 2016; 8:207-216. [PMID: 27644314 PMCID: PMC5161141 DOI: 10.1080/19382014.2016.1235677] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Post-translational modification by bonding of small ubiquitin-like modifier (SUMO) peptides influences various cellular functions, and is regulated by SUMO-specific proteases (SENPs). Several proteins have been suggested to have diverse impact on insulin synthesis and secretion through SUMO modification in β cells. However, the role of SUMO modification in β cell mass has not been established. Here, we examined the changes in expression of Senp in INS1 cells and pancreatic islets under diabetes-relevant stress conditions and associated changes in β cell mass. Treatment with 25 mM glucose for 72 h induced Senp2 mRNA expression but not that of Senp1 in INS1 cells. Immunohistochemical staining with anti-SENP2 antibody on human pancreas sections revealed that SENP2 was localized in the nucleus. Moreover, in a patient with type 2 diabetes, SENP2 levels were enhanced, especially in the cytoplasm. Senp2 cytoplasmic levels were also increased in islet cells in obese diabetic mice. Cell number peaked earlier in INS1 cells cultured in high-glucose conditions compared to those cultured in control media. This finding was associated with increased Ccnd1 mRNA expression in high-glucose conditions, and siRNA-mediated Senp2 suppression abrogated it. Mafa expression, unlike Pdx1, was also dependent on Senp2 expression during high-glucose conditions. In conclusion, Senp2 may play a role in β cell mass in response to chronic high-glucose through Cyclin D1 and Mafa.
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Affiliation(s)
- Hye Seung Jung
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea
- Innovative Research Institute for Cell Therapy, Seoul, Republic of Korea
- CONTACT Hye Seung Jung Department of Internal Medicine, Seoul National University College of Medicine, 101 Daehak-ro, Jongno-gu, Seoul, 03080, Republic of Korea
| | - Yu Mi Kang
- Innovative Research Institute for Cell Therapy, Seoul, Republic of Korea
| | - Ho Seon Park
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Byung Yong Ahn
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Hakmo Lee
- Innovative Research Institute for Cell Therapy, Seoul, Republic of Korea
| | - Min Joo Kim
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Jin Young Jang
- Department of Surgery, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Sun-Whe Kim
- Department of Surgery, Seoul National University College of Medicine, Seoul, Republic of Korea
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44
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Yoshioka Y, Namiki D, Makiuchi M, Sugaya K, Onose JI, Ashida H, Abe N. Vialinin A and thelephantin G, potent inhibitors of tumor necrosis factor-α production, inhibit sentrin/SUMO-specific protease 1 enzymatic activity. Bioorg Med Chem Lett 2016; 26:4237-40. [PMID: 27491710 DOI: 10.1016/j.bmcl.2016.07.051] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Revised: 07/02/2016] [Accepted: 07/22/2016] [Indexed: 11/29/2022]
Abstract
Several p-terphenyl compounds have been isolated from the edible Chinese mushroom Thelephora vialis. Vialinin A, a p-terphenyl compound, strongly inhibits tumor necrosis factor-α production and release. Vialinin A inhibits the enzymatic activity of ubiquitin-specific peptidase 5, one of the target molecules in RBL-2H3 cells. Here we examined the inhibitory effect of p-terphenyl compounds, including vialinin A, against sentrin/SUMO-specific protease 1 (SENP1) enzymatic activity. The half maximal inhibitory concentration values of vialinin A and thelephantin G against full-length SENP1 were 1.64±0.23μM and 2.48±0.02μM, respectively. These findings suggest that p-terphenyl compounds are potent SENP1 inhibitors.
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Affiliation(s)
- Yasukiyo Yoshioka
- Department of Nutritional Science and Food Safety, Faculty of Applied Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka Setagaya-ku, Tokyo 156-8502, Japan; Organization of Advanced Science and Technology, Kobe University, Kobe, Hyogo 657-8501, Japan
| | - Daisuke Namiki
- Department of Nutritional Science and Food Safety, Faculty of Applied Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka Setagaya-ku, Tokyo 156-8502, Japan
| | - Mao Makiuchi
- Department of Nutritional Science and Food Safety, Faculty of Applied Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka Setagaya-ku, Tokyo 156-8502, Japan
| | - Kouichi Sugaya
- Department of Nutritional Science and Food Safety, Faculty of Applied Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka Setagaya-ku, Tokyo 156-8502, Japan
| | - Jun-Ichi Onose
- Department of Nutritional Science and Food Safety, Faculty of Applied Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka Setagaya-ku, Tokyo 156-8502, Japan
| | - Hitoshi Ashida
- Organization of Advanced Science and Technology, Kobe University, Kobe, Hyogo 657-8501, Japan; Department of Agrobioscience, Graduate School of Agricultural Science, Kobe University, Kobe, Hyogo 651-8501, Japan
| | - Naoki Abe
- Department of Nutritional Science and Food Safety, Faculty of Applied Bioscience, Tokyo University of Agriculture, 1-1-1 Sakuragaoka Setagaya-ku, Tokyo 156-8502, Japan.
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45
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Yan-Do R, Duong E, Manning Fox JE, Dai X, Suzuki K, Khan S, Bautista A, Ferdaoussi M, Lyon J, Wu X, Cheley S, MacDonald PE, Braun M. A Glycine-Insulin Autocrine Feedback Loop Enhances Insulin Secretion From Human β-Cells and Is Impaired in Type 2 Diabetes. Diabetes 2016; 65:2311-21. [PMID: 27207556 DOI: 10.2337/db15-1272] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Accepted: 04/26/2016] [Indexed: 11/13/2022]
Abstract
The secretion of insulin from pancreatic islet β-cells is critical for glucose homeostasis. Disrupted insulin secretion underlies almost all forms of diabetes, including the most common form, type 2 diabetes (T2D). The control of insulin secretion is complex and affected by circulating nutrients, neuronal inputs, and local signaling. In the current study, we examined the contribution of glycine, an amino acid and neurotransmitter that activates ligand-gated Cl(-) currents, to insulin secretion from islets of human donors with and without T2D. We find that human islet β-cells express glycine receptors (GlyR), notably the GlyRα1 subunit, and the glycine transporter (GlyT) isoforms GlyT1 and GlyT2. β-Cells exhibit significant glycine-induced Cl(-) currents that promote membrane depolarization, Ca(2+) entry, and insulin secretion from β-cells from donors without T2D. However, GlyRα1 expression and glycine-induced currents are reduced in β-cells from donors with T2D. Glycine is actively cleared by the GlyT expressed within β-cells, which store and release glycine that acts in an autocrine manner. Finally, a significant positive relationship exists between insulin and GlyR, because insulin enhances the glycine-activated current in a phosphoinositide 3-kinase-dependent manner, a positive feedback loop that we find is completely lost in β-cells from donors with T2D.
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Affiliation(s)
- Richard Yan-Do
- Department of Pharmacology and Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Eric Duong
- Department of Pharmacology and Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Jocelyn E Manning Fox
- Department of Pharmacology and Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Xiaoqing Dai
- Department of Pharmacology and Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Kunimasa Suzuki
- Department of Pharmacology and Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Shara Khan
- Department of Pharmacology and Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Austin Bautista
- Department of Pharmacology and Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Mourad Ferdaoussi
- Department of Pharmacology and Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada
| | - James Lyon
- Department of Pharmacology and Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Xichen Wu
- Department of Pharmacology and Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Stephen Cheley
- Department of Pharmacology and Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Patrick E MacDonald
- Department of Pharmacology and Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Matthias Braun
- Department of Pharmacology and Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada
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Schorova L, Martin S. Sumoylation in Synaptic Function and Dysfunction. Front Synaptic Neurosci 2016; 8:9. [PMID: 27199730 PMCID: PMC4848311 DOI: 10.3389/fnsyn.2016.00009] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Accepted: 04/08/2016] [Indexed: 12/18/2022] Open
Abstract
Sumoylation has recently emerged as a key post-translational modification involved in many, if not all, biological processes. Small Ubiquitin-like Modifier (SUMO) polypeptides are covalently attached to specific lysine residues of target proteins through a dedicated enzymatic pathway. Disruption of the SUMO enzymatic pathway in the developing brain leads to lethality indicating that this process exerts a central role during embryonic and post-natal development. However, little is still known regarding how this highly dynamic protein modification is regulated in the mammalian brain despite an increasing number of data implicating sumoylated substrates in synapse formation, synaptic communication and plasticity. The aim of this review is therefore to briefly describe the enzymatic SUMO pathway and to give an overview of our current knowledge on the function and dysfunction of protein sumoylation at the mammalian synapse.
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Affiliation(s)
- Lenka Schorova
- Institut de Pharmacologie Moléculaire et Cellulaire, Centre National de la Recherche Scientifique (UMR7275), University of Nice-Sophia-Antipolis, Laboratory of Excellence "Network for Innovation on Signal Transduction, Pathways in Life Sciences" Valbonne, France
| | - Stéphane Martin
- Institut de Pharmacologie Moléculaire et Cellulaire, Centre National de la Recherche Scientifique (UMR7275), University of Nice-Sophia-Antipolis, Laboratory of Excellence "Network for Innovation on Signal Transduction, Pathways in Life Sciences" Valbonne, France
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47
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Hajmrle C, Smith N, Spigelman AF, Dai X, Senior L, Bautista A, Ferdaoussi M, MacDonald PE. Interleukin-1 signaling contributes to acute islet compensation. JCI Insight 2016; 1:e86055. [PMID: 27699257 DOI: 10.1172/jci.insight.86055] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
IL-1β is a well-established inducer of both insulin resistance and impaired pancreatic islet function. Despite this, findings examining IL-1 receptor deficiency or antagonism in in vivo animal models, as well as in clinical studies of type 2 diabetic (T2D) patients, have led to conflicting results, suggesting that the actions of IL-1β on glycemic control may be pleiotropic in nature. In the present work, we find that the ability of IL-1β to amplify glucose-stimulated insulin secretion from human islets correlates with donor BMI. Islets from obese donors are sensitized to the insulinotropic effects of this cytokine, whereas the stimulatory effects of IL-1β are lost in islets from obese T2D patients, suggesting a role for IL-1 signaling in islet compensation. Indeed, mice deficient in IL-1 receptor type I become glucose intolerant more rapidly than their WT littermates and have impaired secretory responses during the acute stages of inflammatory and metabolic stress induced by LPS and high-fat diet, respectively. IL-1β directly enhances β cell insulin secretion by increasing granule docking and soluble N-ethylmaleimide-sensitive factor attachment receptor (SNARE) complex formation at the plasma membrane. Together, our study highlights the importance of IL-1β signaling in islet compensation to metabolic and inflammatory stress.
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48
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Escudero CA, Herlitz K, Troncoso F, Acurio J, Aguayo C, Roberts JM, Truong G, Duncombe G, Rice G, Salomon C. Role of Extracellular Vesicles and microRNAs on Dysfunctional Angiogenesis during Preeclamptic Pregnancies. Front Physiol 2016; 7:98. [PMID: 27047385 PMCID: PMC4796029 DOI: 10.3389/fphys.2016.00098] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Accepted: 03/01/2016] [Indexed: 01/08/2023] Open
Abstract
Preeclampsia is a syndrome characterized by hypertension during pregnancy, which is a leading cause of morbidity and mortality in both mother and newborn in developing countries. Some advances have increased the understanding of pathophysiology of this disease. For example, reduced utero-placental blood flow associated with impaired trophoblast invasion may lead to a hypoxic placenta that releases harmful materials into the maternal and feto-placental circulation and impairs endothelial function. Identification of these harmful materials is one of the hot topics in the literature, since these provide potential biomarkers. Certainty, such knowledge will help us to understand the miscommunication between mother and fetus. In this review we highlight how placental extracellular vesicles and their cargo, such as small RNAs (i.e., microRNAs), might be involved in endothelial dysfunction, and then in the angiogenesis process, during preeclampsia. Currently only a few reports have addressed the potential role of endothelial regulatory miRNA in the impaired angiogenesis in preeclampsia. One of the main limitations in this area is the variability of the analyses performed in the current literature. This includes variability in the size of the particles analyzed, and broad variation in the exosomes considered. The quantity of microRNA targets genes suggest that practically all endothelial cell metabolic functions might be impaired. More studies are required to investigate mechanisms underlying miRNA released from placenta upon endothelial function involved in the angiogenenic process.
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Affiliation(s)
- Carlos A Escudero
- Group of Investigation in Tumor Angiogenesis, Vascular Physiology Laboratory, Universidad del Bío-BíoChillán, Chile; Group of Research and Innovation in Vascular Health, Department of Basic Sciences, Universidad del Bío-BíoChillán, Chile
| | - Kurt Herlitz
- Group of Investigation in Tumor Angiogenesis, Vascular Physiology Laboratory, Universidad del Bío-Bío Chillán, Chile
| | - Felipe Troncoso
- Group of Investigation in Tumor Angiogenesis, Vascular Physiology Laboratory, Universidad del Bío-Bío Chillán, Chile
| | - Jesenia Acurio
- Group of Investigation in Tumor Angiogenesis, Vascular Physiology Laboratory, Universidad del Bío-Bío Chillán, Chile
| | - Claudio Aguayo
- Group of Research and Innovation in Vascular Health, Department of Basic Sciences, Universidad del Bío-BíoChillán, Chile; Department of Clinical Biochemistry and Immunology, Faculty of Pharmacy, University of ConcepciónConcepción, Chile
| | - James M Roberts
- Departments of Obstetrics, Gynecology and Reproductive Sciences, Epidemiology, and the Clinical and Translational Science Institute, Magee-Womens Research Institute, University of Pittsburgh Pittsburgh, PA, USA
| | - Grace Truong
- Exosome Biology Laboratory, Faculty of Medicine and Biomedical Sciences, Centre for Clinical Diagnostics, UQ Centre for Clinical Research, The University of Queensland Brisbane, QLD, Australia
| | - Gregory Duncombe
- Exosome Biology Laboratory, Faculty of Medicine and Biomedical Sciences, Centre for Clinical Diagnostics, UQ Centre for Clinical Research, The University of Queensland Brisbane, QLD, Australia
| | - Gregory Rice
- Exosome Biology Laboratory, Faculty of Medicine and Biomedical Sciences, Centre for Clinical Diagnostics, UQ Centre for Clinical Research, The University of QueenslandBrisbane, QLD, Australia; Ochsner Clinic Foundation, Maternal-Fetal Medicine, Department of Obstetrics and GynecologyNew Orleans, LA, USA
| | - Carlos Salomon
- Department of Clinical Biochemistry and Immunology, Faculty of Pharmacy, University of ConcepciónConcepción, Chile; Exosome Biology Laboratory, Faculty of Medicine and Biomedical Sciences, Centre for Clinical Diagnostics, UQ Centre for Clinical Research, The University of QueenslandBrisbane, QLD, Australia; Ochsner Clinic Foundation, Maternal-Fetal Medicine, Department of Obstetrics and GynecologyNew Orleans, LA, USA
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49
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Gala-Lopez BL, Pepper AR, Pawlick RL, O'Gorman D, Kin T, Bruni A, Abualhassan N, Bral M, Bautista A, Manning Fox JE, Young LG, MacDonald PE, Shapiro AMJ. Antiaging Glycopeptide Protects Human Islets Against Tacrolimus-Related Injury and Facilitates Engraftment in Mice. Diabetes 2016; 65:451-62. [PMID: 26581595 DOI: 10.2337/db15-0764] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Accepted: 11/10/2015] [Indexed: 02/05/2023]
Abstract
Clinical islet transplantation has become an established treatment modality for selected patients with type 1 diabetes. However, a large proportion of transplanted islets is lost through multiple factors, including immunosuppressant-related toxicity, often requiring more than one donor to achieve insulin independence. On the basis of the cytoprotective capabilities of antifreeze proteins (AFPs), we hypothesized that supplementation of islets with synthetic AFP analog antiaging glycopeptide (AAGP) would enhance posttransplant engraftment and function and protect against tacrolimus (Tac) toxicity. In vitro and in vivo islet Tac exposure elicited significant but reversible reduction in insulin secretion in both mouse and human islets. Supplementation with AAGP resulted in improvement of islet survival (Tac(+) vs. Tac+AAGP, 31.5% vs. 67.6%, P < 0.01) coupled with better insulin secretion (area under the curve: Tac(+) vs. Tac+AAGP, 7.3 vs. 129.2 mmol/L/60 min, P < 0.001). The addition of AAGP reduced oxidative stress, enhanced insulin exocytosis, improved apoptosis, and improved engraftment in mice by decreasing expression of interleukin (IL)-1β, IL-6, keratinocyte chemokine, and tumor necrosis factor-α. Finally, transplant efficacy was superior in the Tac+AAGP group and was similar to islets not exposed to Tac, despite receiving continuous treatment for a limited time. Thus, supplementation with AAGP during culture improves islet potency and attenuates long-term Tac-induced graft dysfunction.
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Affiliation(s)
- Boris L Gala-Lopez
- Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada Canadian National Transplant Research Program, University of Alberta, Edmonton, Alberta, Canada
| | - Andrew R Pepper
- Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada Canadian National Transplant Research Program, University of Alberta, Edmonton, Alberta, Canada
| | - Rena L Pawlick
- Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Doug O'Gorman
- Clinical Islet Transplant Program, University of Alberta, Edmonton, Alberta, Canada
| | - Tatsuya Kin
- Clinical Islet Transplant Program, University of Alberta, Edmonton, Alberta, Canada
| | - Antonio Bruni
- Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada Canadian National Transplant Research Program, University of Alberta, Edmonton, Alberta, Canada
| | - Nasser Abualhassan
- Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada Canadian National Transplant Research Program, University of Alberta, Edmonton, Alberta, Canada
| | - Mariusz Bral
- Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada
| | - Austin Bautista
- Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada Department of Pharmacology, University of Alberta, Edmonton, Alberta, Canada
| | - Jocelyn E Manning Fox
- Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada Department of Pharmacology, University of Alberta, Edmonton, Alberta, Canada
| | - Lachlan G Young
- ProtoKinetix Inc., Vancouver, Vancouver, British Columbia, Canada
| | - Patrick E MacDonald
- Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada Department of Pharmacology, University of Alberta, Edmonton, Alberta, Canada
| | - A M James Shapiro
- Alberta Diabetes Institute, University of Alberta, Edmonton, Alberta, Canada Canadian National Transplant Research Program, University of Alberta, Edmonton, Alberta, Canada Clinical Islet Transplant Program, University of Alberta, Edmonton, Alberta, Canada
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50
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Craig TJ, Anderson D, Evans AJ, Girach F, Henley JM. SUMOylation of Syntaxin1A regulates presynaptic endocytosis. Sci Rep 2015; 5:17669. [PMID: 26635000 PMCID: PMC4669484 DOI: 10.1038/srep17669] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Accepted: 11/03/2015] [Indexed: 12/27/2022] Open
Abstract
Neurotransmitter release from the presynaptic terminal is under very precise spatial and temporal control. Following neurotransmitter release, synaptic vesicles are recycled by endocytosis and refilled with neurotransmitter. During the exocytosis event leading to release, SNARE proteins provide most of the mechanical force for membrane fusion. Here, we show one of these proteins, Syntaxin1A, is SUMOylated near its C-terminal transmembrane domain in an activity-dependent manner. Preventing SUMOylation of Syntaxin1A reduces its interaction with other SNARE proteins and disrupts the balance of synaptic vesicle endo/exocytosis, resulting in an increase in endocytosis. These results indicate that SUMOylation regulates the emerging role of Syntaxin1A in vesicle endocytosis, which in turn, modulates neurotransmitter release and synaptic function.
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Affiliation(s)
- Tim J Craig
- School of Biochemistry, Medical Sciences Building, University of Bristol, University Walk, Bristol, BS8 1TD, U.K
| | - Dina Anderson
- School of Biochemistry, Medical Sciences Building, University of Bristol, University Walk, Bristol, BS8 1TD, U.K
| | - Ashley J Evans
- School of Biochemistry, Medical Sciences Building, University of Bristol, University Walk, Bristol, BS8 1TD, U.K
| | - Fatima Girach
- School of Biochemistry, Medical Sciences Building, University of Bristol, University Walk, Bristol, BS8 1TD, U.K
| | - Jeremy M Henley
- School of Biochemistry, Medical Sciences Building, University of Bristol, University Walk, Bristol, BS8 1TD, U.K
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