1
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Li X, Yu T, Li X, He X, Zhang B, Yang Y. Role of novel protein acylation modifications in immunity and its related diseases. Immunology 2024. [PMID: 38866391 DOI: 10.1111/imm.13822] [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: 11/30/2023] [Accepted: 05/21/2024] [Indexed: 06/14/2024] Open
Abstract
The cross-regulation of immunity and metabolism is currently a research hotspot in life sciences and immunology. Metabolic immunology plays an important role in cutting-edge fields such as metabolic regulatory mechanisms in immune cell development and function, and metabolic targets and immune-related disease pathways. Protein post-translational modification (PTM) is a key epigenetic mechanism that regulates various biological processes and highlights metabolite functions. Currently, more than 400 PTM types have been identified to affect the functions of several proteins. Among these, metabolic PTMs, particularly various newly identified histone or non-histone acylation modifications, can effectively regulate various functions, processes and diseases of the immune system, as well as immune-related diseases. Thus, drugs aimed at targeted acylation modification can have substantial therapeutic potential in regulating immunity, indicating a new direction for further clinical translational research. This review summarises the characteristics and functions of seven novel lysine acylation modifications, including succinylation, S-palmitoylation, lactylation, crotonylation, 2-hydroxyisobutyrylation, β-hydroxybutyrylation and malonylation, and their association with immunity, thereby providing valuable references for the diagnosis and treatment of immune disorders associated with new acylation modifications.
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Affiliation(s)
- Xiaoqian Li
- Department of Immunology, School of Basic Medicine, Qingdao University, Qingdao, People's Republic of China
| | - Tao Yu
- Institute for Translational Medicine, The Affiliated Hospital of Qingdao University, Qingdao, People's Republic of China
| | - Xiaolu Li
- Department of Cardiac Ultrasound, The Affiliated Hospital of Qingdao University, Qingdao, People's Republic of China
| | - Xiangqin He
- Department of Cardiac Ultrasound, The Affiliated Hospital of Qingdao University, Qingdao, People's Republic of China
| | - Bei Zhang
- Department of Immunology, School of Basic Medicine, Qingdao University, Qingdao, People's Republic of China
| | - Yanyan Yang
- Department of Immunology, School of Basic Medicine, Qingdao University, Qingdao, People's Republic of China
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2
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Yan W, Xie C, Sun S, Zheng Q, Wang J, Wang Z, Man CH, Wang H, Yang Y, Wang T, Shi L, Zhang S, Huang C, Xu S, Wang YP. SUCLG1 restricts POLRMT succinylation to enhance mitochondrial biogenesis and leukemia progression. EMBO J 2024; 43:2337-2367. [PMID: 38649537 PMCID: PMC11183053 DOI: 10.1038/s44318-024-00101-9] [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: 09/27/2023] [Revised: 03/21/2024] [Accepted: 03/22/2024] [Indexed: 04/25/2024] Open
Abstract
Mitochondria are cellular powerhouses that generate energy through the electron transport chain (ETC). The mitochondrial genome (mtDNA) encodes essential ETC proteins in a compartmentalized manner, however, the mechanism underlying metabolic regulation of mtDNA function remains unknown. Here, we report that expression of tricarboxylic acid cycle enzyme succinate-CoA ligase SUCLG1 strongly correlates with ETC genes across various TCGA cancer transcriptomes. Mechanistically, SUCLG1 restricts succinyl-CoA levels to suppress the succinylation of mitochondrial RNA polymerase (POLRMT). Lysine 622 succinylation disrupts the interaction of POLRMT with mtDNA and mitochondrial transcription factors. SUCLG1-mediated POLRMT hyposuccinylation maintains mtDNA transcription, mitochondrial biogenesis, and leukemia cell proliferation. Specifically, leukemia-promoting FMS-like tyrosine kinase 3 (FLT3) mutations modulate nuclear transcription and upregulate SUCLG1 expression to reduce succinyl-CoA and POLRMT succinylation, resulting in enhanced mitobiogenesis. In line, genetic depletion of POLRMT or SUCLG1 significantly delays disease progression in mouse and humanized leukemia models. Importantly, succinyl-CoA level and POLRMT succinylation are downregulated in FLT3-mutated clinical leukemia samples, linking enhanced mitobiogenesis to cancer progression. Together, SUCLG1 connects succinyl-CoA with POLRMT succinylation to modulate mitochondrial function and cancer development.
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Affiliation(s)
- Weiwei Yan
- Precision Research Center for Refractory Diseases, Institute for Clinical Research, Shanghai Key Laboratory of Pancreatic Disease, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, 200080, Shanghai, China
| | - Chengmei Xie
- Precision Research Center for Refractory Diseases, Institute for Clinical Research, Shanghai Key Laboratory of Pancreatic Disease, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, 200080, Shanghai, China
| | - Sijun Sun
- Precision Research Center for Refractory Diseases, Institute for Clinical Research, Shanghai Key Laboratory of Pancreatic Disease, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, 200080, Shanghai, China
- Department of Gastrointestinal Surgery, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, 200080, Shanghai, China
| | - Quan Zheng
- Center for Single-Cell Omics, School of Public Health, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Jingyi Wang
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, 200080, Shanghai, China
| | - Zihao Wang
- Institutes of Biomedical Sciences, Shanghai Medical College, Fudan University, 200032, Shanghai, China
| | - Cheuk-Him Man
- Division of Haematology, Department of Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
| | - Haiyan Wang
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, 200080, Shanghai, China
| | - Yunfan Yang
- Department of Cell Biology, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, 250012, Jinan, China
| | - Tianshi Wang
- Department of Biochemistry and Molecular Cell Biology, Shanghai Jiao Tong University School of Medicine, 200025, Shanghai, China
| | - Leilei Shi
- Precision Research Center for Refractory Diseases, Institute for Clinical Research, Shanghai Key Laboratory of Pancreatic Disease, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, 200080, Shanghai, China
| | - Shengjie Zhang
- Precision Research Center for Refractory Diseases, Institute for Clinical Research, Shanghai Key Laboratory of Pancreatic Disease, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, 200080, Shanghai, China.
| | - Chen Huang
- Department of Gastrointestinal Surgery, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, 200080, Shanghai, China.
| | - Shuangnian Xu
- Department of Hematology, Southwest Hospital, Army Medical University, 400038, Chongqing, China.
| | - Yi-Ping Wang
- Precision Research Center for Refractory Diseases, Institute for Clinical Research, Shanghai Key Laboratory of Pancreatic Disease, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, 200080, Shanghai, China.
- Institutes of Biomedical Sciences, Shanghai Medical College, Fudan University, 200032, Shanghai, China.
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3
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Sabadell-Basallote J, Astiarraga B, Castaño C, Ejarque M, Repollés-de-Dalmau M, Quesada I, Blanco J, Nuñez-Roa C, Rodríguez-Peña MM, Martínez L, De Jesus DF, Marroqui L, Bosch R, Montanya E, Sureda FX, Tura A, Mari A, Kulkarni RN, Vendrell J, Fernández-Veledo S. SUCNR1 regulates insulin secretion and glucose elevates the succinate response in people with prediabetes. J Clin Invest 2024; 134:e173214. [PMID: 38713514 PMCID: PMC11178533 DOI: 10.1172/jci173214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 04/26/2024] [Indexed: 05/09/2024] Open
Abstract
Pancreatic β-cell dysfunction is a key feature of type 2 diabetes, and novel regulators of insulin secretion are desirable. Here we report that the succinate receptor (SUCNR1) is expressed in β-cells and is up-regulated in hyperglycemic states in mice and humans. We found that succinate acts as a hormone-like metabolite and stimulates insulin secretion via a SUCNR1-Gq-PKC-dependent mechanism in human β-cells. Mice with β-cell-specific Sucnr1 deficiency exhibit impaired glucose tolerance and insulin secretion on a high-fat diet, indicating that SUCNR1 is essential for preserving insulin secretion in diet-induced insulin resistance. Patients with impaired glucose tolerance show an enhanced nutritional-related succinate response, which correlates with the potentiation of insulin secretion during intravenous glucose administration. These data demonstrate that the succinate/SUCNR1 axis is activated by high glucose and identify a GPCR-mediated amplifying pathway for insulin secretion relevant to the hyperinsulinemia of prediabetic states.
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Affiliation(s)
- Joan Sabadell-Basallote
- Unitat de Recerca, Hospital Universitari Joan XXIII, Insitut d'Investigació Sanitària Pere Virgili, Tarragona, Spain
| | - Brenno Astiarraga
- Unitat de Recerca, Hospital Universitari Joan XXIII, Insitut d'Investigació Sanitària Pere Virgili, Tarragona, Spain
| | - Carlos Castaño
- Unitat de Recerca, Hospital Universitari Joan XXIII, Institut d'Investigació Sanitària Pere Virgili, Tarragona, Spain
| | - Miriam Ejarque
- Unitat de Recerca, Hospital Universitari Joan XXIII, Insitut d'Investigació Sanitària Pere Virgili, Tarragona, Spain
| | - Maria Repollés-de-Dalmau
- Unitat de Recerca, Hospital Universitari Joan XXIII, Insitut d'Investigació Sanitària Pere Virgili, Tarragona, Spain
| | - Ivan Quesada
- CIBER de Diabetes y Enfermedades Metabólicas Asociadas, Instituto de Salud Carlos III, ELCHE, Spain
| | - Jordi Blanco
- Departament de Medicina i Cirurgia, Universitat Rovira i Virgili, Reus, Spain
| | - Catalina Nuñez-Roa
- Unitat de Recerca, Hospital Universitari Joan XXIII, Institut d'Investigació Sanitària Pere Virgili, Tarragona, Spain
| | - M-Mar Rodríguez-Peña
- Unitat de Recerca, Hospital Universitari Joan XXIII, Institut d'Investigació Sanitària Pere Virgili, Tarragona, Spain
| | - Laia Martínez
- Unitat de Recerca, Hospital Universitari Joan XXIII, Institut d'Investigació Sanitària Pere Virgili, Tarragona, Spain
| | - Dario F De Jesus
- Section of Islet Cell and Regenerative Biology, Joslin Diabetes Center, Boston, United States of America
| | - Laura Marroqui
- CIBER de Diabetes y Enfermedades Metabólicas Asociadas, Instituto de Salud Carlos III, ELCHE, Spain
| | - Ramon Bosch
- Unitat de Recerca, Hospital Universitari Joan XXIII, Insitut d'Investigació Sanitària Pere Virgili, Tarragona, Spain
| | - Eduard Montanya
- CIBER de Diabetes y Enfermedades Metabólicas Asociadas, Instituto de Salud Carlos III, ELCHE, Spain
| | - Francesc X Sureda
- Section of Islet Cell and Regenerative Biology, Joslin Diabetes Center, Boston, United States of America
| | - Andrea Tura
- Institute of Neuroscience, National Research Council, Padova, Italy
| | - Andrea Mari
- Institute of Neuroscience, National Research Council, Padova, Italy
| | - Rohit N Kulkarni
- Section of Islet Cell and Regenerative Biology, Joslin Diabetes Center, Boston, United States of America
| | - Joan Vendrell
- Unitat de Recerca, Hospital Universitari Joan XXIII, Institut d'Investigació Sanitària Pere Virgili, Tarragona, Spain
| | - Sonia Fernández-Veledo
- Unitat de Recerca, Hospital Universitari Joan XXIII, Institut d'Investigació Sanitària Pere Virgili, Tarragona, Spain
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4
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Varney MJ, Benovic JL. The Role of G Protein-Coupled Receptors and Receptor Kinases in Pancreatic β-Cell Function and Diabetes. Pharmacol Rev 2024; 76:267-299. [PMID: 38351071 PMCID: PMC10877731 DOI: 10.1124/pharmrev.123.001015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Revised: 12/01/2023] [Accepted: 12/07/2023] [Indexed: 02/16/2024] Open
Abstract
Type 2 diabetes (T2D) mellitus has emerged as a major global health concern that has accelerated in recent years due to poor diet and lifestyle. Afflicted individuals have high blood glucose levels that stem from the inability of the pancreas to make enough insulin to meet demand. Although medication can help to maintain normal blood glucose levels in individuals with chronic disease, many of these medicines are outdated, have severe side effects, and often become less efficacious over time, necessitating the need for insulin therapy. G protein-coupled receptors (GPCRs) regulate many physiologic processes, including blood glucose levels. In pancreatic β cells, GPCRs regulate β-cell growth, apoptosis, and insulin secretion, which are all critical in maintaining sufficient β-cell mass and insulin output to ensure euglycemia. In recent years, new insights into the signaling of incretin receptors and other GPCRs have underscored the potential of these receptors as desirable targets in the treatment of diabetes. The signaling of these receptors is modulated by GPCR kinases (GRKs) that phosphorylate agonist-activated GPCRs, marking the receptor for arrestin binding and internalization. Interestingly, genome-wide association studies using diabetic patient cohorts link the GRKs and arrestins with T2D. Moreover, recent reports show that GRKs and arrestins expressed in the β cell serve a critical role in the regulation of β-cell function, including β-cell growth and insulin secretion in both GPCR-dependent and -independent pathways. In this review, we describe recent insights into GPCR signaling and the importance of GRK function in modulating β-cell physiology. SIGNIFICANCE STATEMENT: Pancreatic β cells contain a diverse array of G protein-coupled receptors (GPCRs) that have been shown to improve β-cell function and survival, yet only a handful have been successfully targeted in the treatment of diabetes. This review discusses recent advances in our understanding of β-cell GPCR pharmacology and regulation by GPCR kinases while also highlighting the necessity of investigating islet-enriched GPCRs that have largely been unexplored to unveil novel treatment strategies.
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Affiliation(s)
- Matthew J Varney
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Jeffrey L Benovic
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania
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5
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Adejor J, Tumukunde E, Li G, Lin H, Xie R, Wang S. Impact of Lysine Succinylation on the Biology of Fungi. Curr Issues Mol Biol 2024; 46:1020-1046. [PMID: 38392183 PMCID: PMC10888112 DOI: 10.3390/cimb46020065] [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: 12/09/2023] [Revised: 01/02/2024] [Accepted: 01/03/2024] [Indexed: 02/24/2024] Open
Abstract
Post-translational modifications (PTMs) play a crucial role in protein functionality and the control of various cellular processes and secondary metabolites (SMs) in fungi. Lysine succinylation (Ksuc) is an emerging protein PTM characterized by the addition of a succinyl group to a lysine residue, which induces substantial alteration in the chemical and structural properties of the affected protein. This chemical alteration is reversible, dynamic in nature, and evolutionarily conserved. Recent investigations of numerous proteins that undergo significant succinylation have underscored the potential significance of Ksuc in various biological processes, encompassing normal physiological functions and the development of certain pathological processes and metabolites. This review aims to elucidate the molecular mechanisms underlying Ksuc and its diverse functions in fungi. Both conventional investigation techniques and predictive tools for identifying Ksuc sites were also considered. A more profound comprehension of Ksuc and its impact on the biology of fungi have the potential to unveil new insights into post-translational modification and may pave the way for innovative approaches that can be applied across various clinical contexts in the management of mycotoxins.
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Affiliation(s)
- John Adejor
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Elisabeth Tumukunde
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Guoqi Li
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Hong Lin
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Rui Xie
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Shihua Wang
- Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, Key Laboratory of Biopesticide and Chemical Biology of Education Ministry, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou 350002, China
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6
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Malik A, Sharif A, Zubair HM, Akhtar B, Mobashar A. In Vitro, In Silico, and In Vivo Studies of Cardamine hirsuta Linn as a Potential Antidiabetic Agent in a Rat Model. ACS OMEGA 2023; 8:22623-22636. [PMID: 37396280 PMCID: PMC10308569 DOI: 10.1021/acsomega.3c01034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Accepted: 05/30/2023] [Indexed: 07/04/2023]
Abstract
Diabetes mellitus (T2DM) is a multifaceted metabolic disorder with no definite treatment. In silico characterization can help to explain the interaction between molecules and predict 3D structures. The aim of the present study was to evaluate the hypoglycemic activities of the hydro-methanolic extract of Cardamine hirsuta in a rat model. In vitro antioxidant and α-amylase inhibitory assays were evaluated in the present study. Phyto-constituents were quantified using RP-UHPLC-MS analysis. Molecular docking of compounds into the binding site of different molecular targets, i.e., tumor necrosis factor (TNF-α), glycogen synthase kinase 3 β (GSK-3β), and AKT, was carried out. Acute toxicity model, in vivo antidiabetic effect, and the influence on biochemical and oxidative stress parameters were also investigated. T2DM was induced in adult male rats by streptozotocin using a high-fat diet model. Three different doses (125, 250, and 500 mg/kg BW) were orally gavaged for 30 days. Mulberrofuran-M and quercetin3-(6″caffeoylsophoroside) have demonstrated remarkable binding affinity toward TNF-α and GSK-3β, respectively. 2,2-Diphenyl-1-picrylhydrazyl and α-amylase inhibition assay exhibited IC50 values of 75.96 and 73.66 μg/mL, respectively. In vivo findings exhibited that 500 mg/kg body weight (BW) dose of the extract significantly decreased the blood glucose level, improved biochemical parameters as well as oxidative stress by reduction of lipid peroxidation, and increased high-density lipoproteins. Moreover, activities of glutathione-s-transferase, reduced glutathione, superoxide dismutase were enhanced, and cellular architecture in the histopathological examination was restored in treatment groups. The present study affirmed the antidiabetic activities of mulberrofuran-M and quercetin3-(6″caffeoylsophoroside) present in the hydro-methanolic extract of C. hirsuta, possibly due to the reduction in oxidative stress and α-amylase inhibition.
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Affiliation(s)
- Aqna Malik
- Department
of Pharmacology, Faculty of Pharmacy, The
University of Lahore, Lahore 54000, Pakistan
| | - Ali Sharif
- Department
of Pharmacology, Faculty of Pharmacy, The
University of Lahore, Lahore 54000, Pakistan
| | - Hafiz Muhammad Zubair
- Department
of Pharmacology, Faculty of Pharmacy, The
University of Lahore, Lahore 54000, Pakistan
| | - Bushra Akhtar
- Department
of Pharmacy, University of Agriculture, Faisalabad 38000, Pakistan
| | - Aisha Mobashar
- Department
of Pharmacology, Faculty of Pharmacy, The
University of Lahore, Lahore 54000, Pakistan
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7
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Cobb J, Soliman SSM, Retuerto M, Quijano JC, Orr C, Ghannoum M, Kandeel F, Husseiny MI. Changes in the gut microbiota of NOD mice in response to an oral Salmonella-based vaccine against type 1 diabetes. PLoS One 2023; 18:e0285905. [PMID: 37224176 DOI: 10.1371/journal.pone.0285905] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Accepted: 05/03/2023] [Indexed: 05/26/2023] Open
Abstract
We developed an oral Salmonella-based vaccine that prevents and reverses diabetes in non-obese diabetic (NOD) mice. Related to this, the gastrointestinal tract harbors a complex dynamic population of microorganisms, the gut microbiome, that influences host homeostasis and metabolism. Changes in the gut microbiome are associated with insulin dysfunction and type 1 diabetes (T1D). Oral administration of diabetic autoantigens as a vaccine can restore immune balance. However, it was not known if a Salmonella-based vaccine would impact the gut microbiome. We administered a Salmonella-based vaccine to prediabetic NOD mice. Changes in the gut microbiota and associated metabolome were assessed using next-generation sequencing and gas chromatography-mass spectrometry (GC-MS). The Salmonella-based vaccine did not cause significant changes in the gut microbiota composition immediately after vaccination although at 30 days post-vaccination changes were seen. Additionally, no changes were noted in the fecal mycobiome between vaccine- and control/vehicle-treated mice. Significant changes in metabolic pathways related to inflammation and proliferation were found after vaccine administration. The results from this study suggest that an oral Salmonella-based vaccine alters the gut microbiome and metabolome towards a more tolerant composition. These results support the use of orally administered Salmonella-based vaccines that induced tolerance after administration.
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Affiliation(s)
- Jacob Cobb
- Department of Translational Research & Cellular Therapeutics, Arthur Riggs Diabetes & Metabolism Research Institute, Beckman Research Institute, City of Hope National Medical Center, Duarte, California, United States of America
| | - Sameh S M Soliman
- Research Institute for Medical and Health Sciences, University of Sharjah, Sharjah, United Arab Emirates
- Department of Medicinal Chemistry, College of Pharmacy, University of Sharjah, Sharjah, United Arab Emirates
| | - Mauricio Retuerto
- Center for Medical Mycology, Department of Dermatology, University Hospitals Cleveland Medical Center, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Janine C Quijano
- Department of Translational Research & Cellular Therapeutics, Arthur Riggs Diabetes & Metabolism Research Institute, Beckman Research Institute, City of Hope National Medical Center, Duarte, California, United States of America
| | - Chris Orr
- Department of Translational Research & Cellular Therapeutics, Arthur Riggs Diabetes & Metabolism Research Institute, Beckman Research Institute, City of Hope National Medical Center, Duarte, California, United States of America
| | - Mahmoud Ghannoum
- Center for Medical Mycology, Department of Dermatology, University Hospitals Cleveland Medical Center, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Fouad Kandeel
- Department of Translational Research & Cellular Therapeutics, Arthur Riggs Diabetes & Metabolism Research Institute, Beckman Research Institute, City of Hope National Medical Center, Duarte, California, United States of America
| | - Mohamed I Husseiny
- Department of Translational Research & Cellular Therapeutics, Arthur Riggs Diabetes & Metabolism Research Institute, Beckman Research Institute, City of Hope National Medical Center, Duarte, California, United States of America
- Faculty of Pharmacy, Zagazig University, Zagazig, Egypt
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8
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Varney MJ, Steyaert W, Coucke PJ, Delanghe JR, Uehling DE, Joseph B, Marcellus R, Al-Awar R, Benovic JL. G protein-coupled receptor kinase 6 (GRK6) regulates insulin processing and secretion via effects on proinsulin conversion to insulin. J Biol Chem 2022; 298:102421. [PMID: 36030052 PMCID: PMC9526158 DOI: 10.1016/j.jbc.2022.102421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Revised: 08/16/2022] [Accepted: 08/18/2022] [Indexed: 11/07/2022] Open
Abstract
Recent studies identified a missense mutation in the gene coding for G protein–coupled receptor kinase 6 (GRK6) that segregates with type 2 diabetes (T2D). To better understand how GRK6 might be involved in T2D, we used pharmacological inhibition and genetic knockdown in the mouse β-cell line, MIN6, to determine whether GRK6 regulates insulin dynamics. We show inhibition of GRK5 and GRK6 increased insulin secretion but reduced insulin processing while GRK6 knockdown revealed these same processing defects with reduced levels of cellular insulin. GRK6 knockdown cells also had attenuated insulin secretion but enhanced proinsulin secretion consistent with decreased processing. In support of these findings, we demonstrate GRK6 rescue experiments in knockdown cells restored insulin secretion after glucose treatment. The altered insulin profile appears to be caused by changes in the proprotein convertases, the enzymes responsible for proinsulin to insulin conversion, as GRK6 knockdown resulted in significantly reduced convertase expression and activity. To identify how the GRK6-P384S mutation found in T2D patients might affect insulin processing, we performed biochemical and cell biological assays to study the properties of the mutant. We found that while GRK6-P384S was more active than WT GRK6, it displayed a cytosolic distribution in cells compared to the normal plasma membrane localization of GRK6. Additionally, GRK6 overexpression in MIN6 cells enhanced proinsulin processing, while GRK6-P384S expression had little effect. Taken together, our data show that GRK6 regulates insulin processing and secretion in a glucose-dependent manner and provide a foundation for understanding the contribution of GRK6 to T2D.
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Affiliation(s)
- Matthew J Varney
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Wouter Steyaert
- Department of Human Genetics, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, the Netherlands; Center for Medical Genetics, Ghent University and Ghent University Hospital, Ghent, Belgium
| | - Paul J Coucke
- Center for Medical Genetics, Ghent University and Ghent University Hospital, Ghent, Belgium
| | - Joris R Delanghe
- Department of Diagnostic Sciences, Ghent University, Ghent, Belgium
| | - David E Uehling
- Drug Discovery Program, Ontario Institute for Cancer Research, Toronto, Ontario M5G 0A3, Canada
| | - Babu Joseph
- Drug Discovery Program, Ontario Institute for Cancer Research, Toronto, Ontario M5G 0A3, Canada
| | - Richard Marcellus
- Drug Discovery Program, Ontario Institute for Cancer Research, Toronto, Ontario M5G 0A3, Canada
| | - Rima Al-Awar
- Drug Discovery Program, Ontario Institute for Cancer Research, Toronto, Ontario M5G 0A3, Canada; Department of Pharmacology and Toxicology, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Jeffrey L Benovic
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA.
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9
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Idu MD, Edehia O–O, Gabriel BO. Anti-diabetic effect of Stachytarpheta jamaicensis on low dose streptozotocin-induced diabetic rats fed on a high-fat diet. CLINICAL PHYTOSCIENCE 2021. [DOI: 10.1186/s40816-021-00326-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Abstract
Introduction
This study evaluates the anti-diabetic effect of ethanol extract of Stachytarpheta jamaicensis leaf on streptozotocin (STZ) - induced diabetic rats fed on high-fat diet (HFD).
Methods
Sets of male albino rats of the Wistar strain weighing between 180 and 250 g were exposed to high fat diet (margarine and oil from vegetable sources in a ratio of 2:1 w/v) for 3 weeks. Then the animals were fasted overnight; hyperglycemic state was induced using reduced dose of streptozotocin (35 mg/kg) and animals were randomly divided into five groups (n = 7); group A received the HFD + STZ (35 mg/kg i.p.); group B received HFD + STZ + gliberclamide (10 mg/kg; i.p); groups C, D and E were administered the HFD + streptozotocin with different doses of the ethanol extract (30, 35 and 100 mg/kg p.o., respectively).
Results
Results showed significant (p < 0.05) decrease in blood glucose concentration of the rats treated with different doses of S. jamaicensis extract and those treated with gliberclamide compared to the untreated diabetic rats (negative control). Significant (p < 0.05) reductions in activities of serum AST, ALP, total protein and bilirubin were noticed in the groups in contrast to the control. Levels of urea, creatinine, potassium and chloride were considerably (p < 0.05) low while sodium and bicarbonate levels were high in the groups except the control. Lipid profile revealed significant (p < 0.05) reduction in total cholesterol, triacylglycerol, LDL, VLDL while HDL levels were high in the groups compared to the control. The extract significantly (p < 0.05) ameliorated weight loss. Histopathology of the liver, kidney and pancreas showed ameliorative effect of the extract against the deleterious changes occasioned by the HFD and STZ induced diabetic state.
Conclusion
These findings have provided scientific basis for the use of S. jamaicensis in the treatment of diabetes mellitus in ethnomedicinal practices in Nigeria.
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10
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Gabriel BO, Idu MD. Anti-diuretic and anti-glycemic properties of Jatropha gossypiifolia L. leave extract on wistar rats. CLINICAL PHYTOSCIENCE 2021. [DOI: 10.1186/s40816-021-00329-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Abstract
Background
Jatropha gossypiifolia L. is a widespread plant in tropical and sub-tropical countries used in traditional medicine. This study investigated the anti-diuretic and anti-hyperglycemia activities of J. gossypiifolia leave extract on streptozotocin-induced diabetic rats.
Methods
The leaves was shade dried, pulverized and prepared into extract. 30, 50 and 100 mg/kg of the leaves extracts of J. gossypiifolia was subject to diuretics and hyperglycemic properties using established protocol of diuretic and diabetes test on the rat bladders emptied via mild compression in the pelvic region and gently pulling of their tails. 0.5 ml/kg normal saline, reference drug and the tested were administered with a single dose of the various drugs, and Streptozotocin (STZ) was freshly prepared in 0.1 M citrate buffer with pH 4.5 prior to induction, animals were fasted 24 h and single dose of 45 mg STZ per kg body weight was administered intraperitoneally. Urine and blood samples were isolated from rats and centrifuged for the determination of renal function test. Diuretic and antidiabetic indexes where evaluated using adopted method.
Results
This study showed that, graded doses of the extract significantly increased diuretic effect, specifically at 100 mg/kg increased diuretic index at 4.29 and urine volume 5.06 and 10 mg/kg Hydrochlorothiazide with 6.23 ml when compared untreated group (1.18 ml) (p < 0.0001). Also, it regulated renal function in homeostatic state. Graded doses at (30, 50 and 100 mg/kg) of the extract significantly reduced streptozotocine induced increased blood glucose level at day 14 (84.00, 60.67 and 42.00 IU/mL) when compared with 20 mg/kg glibenclamide and diabetics control (81.67 and 463.00 IU/mL) (p > 0.05). Also, the extract maintained a normal body mass indexes, biochemical and anatomical structure.
Conclusion
The effect associated with J. gossypiifolia potentiated its anti-diuretic and anti-hyperglycemic properties as early stated in the ethnomedicinal reports.
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11
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Corkey BE, Deeney JT, Merrins MJ. What Regulates Basal Insulin Secretion and Causes Hyperinsulinemia? Diabetes 2021; 70:2174-2182. [PMID: 34593535 PMCID: PMC8576498 DOI: 10.2337/dbi21-0009] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Accepted: 07/28/2021] [Indexed: 12/12/2022]
Abstract
We hypothesize that basal hyperinsulinemia is synergistically mediated by an interplay between increased oxidative stress and excess lipid in the form of reactive oxygen species (ROS) and long-chain acyl-CoA esters (LC-CoA). In addition, ROS production may increase in response to inflammatory cytokines and certain exogenous environmental toxins that mislead β-cells into perceiving nutrient excess when none exists. Thus, basal hyperinsulinemia is envisioned as an adaptation to sustained real or perceived nutrient excess that only manifests as a disease when the excess demand can no longer be met by an overworked β-cell. In this article we will present a testable hypothetical mechanism to explain the role of lipids and ROS in basal hyperinsulinemia and how they differ from glucose-stimulated insulin secretion (GSIS). The model centers on redox regulation, via ROS, and S-acylation-mediated trafficking via LC-CoA. These pathways are well established in neural systems but not β-cells. During GSIS, these signals rise and fall in an oscillatory pattern, together with the other well-established signals derived from glucose metabolism; however, their precise roles have not been defined. We propose that failure to either increase or decrease ROS or LC-CoA appropriately will disturb β-cell function.
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Affiliation(s)
- Barbara E Corkey
- Department of Medicine, Boston University School of Medicine, Boston, MA
| | - Jude T Deeney
- Department of Medicine, Boston University School of Medicine, Boston, MA
| | - Matthew J Merrins
- Department of Biomolecular Chemistry and Section of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI
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12
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Fernández-Veledo S, Ceperuelo-Mallafré V, Vendrell J. Rethinking succinate: an unexpected hormone-like metabolite in energy homeostasis. Trends Endocrinol Metab 2021; 32:680-692. [PMID: 34301438 DOI: 10.1016/j.tem.2021.06.003] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 06/15/2021] [Accepted: 06/16/2021] [Indexed: 02/07/2023]
Abstract
There has been an explosion of interest in the signaling capacity of energy metabolites. A prime example is the Krebs cycle substrate succinate, an archetypal respiratory substrate with functions beyond energy production as an intracellular and extracellular signaling molecule. Long associated with inflammation, emerging evidence supports a key role for succinate in metabolic processes relating to energy management. As the natural ligand for SUCNR1, a G protein-coupled receptor, succinate is akin to hormones and likely functions as a reporter of metabolism and stress. In this review, we reconcile new and old observations to outline a regulatory role for succinate in metabolic homeostasis. We highlight the importance of the succinate-SUCNR1 axis in metabolic diseases as an integrator of macrophage immune response, and we discuss new metabolic functions recently ascribed to succinate in specific tissues. Because circulating succinate has emerged as a promising biomarker in chronic metabolic diseases, a better understanding of the physiopathological role of the succinate-SUCNR1 axis in metabolism might open new avenues for clinical use in patients with obesity or diabetes.
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Affiliation(s)
- Sonia Fernández-Veledo
- Department of Endocrinology and Nutrition and Research Unit, University Hospital of Tarragona Joan XXIII, Institut d'Investigació Sanitària Pere Virgili (IISPV), Tarragona, Spain; CIBER de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Madrid, Spain.
| | - Victòria Ceperuelo-Mallafré
- Department of Endocrinology and Nutrition and Research Unit, University Hospital of Tarragona Joan XXIII, Institut d'Investigació Sanitària Pere Virgili (IISPV), Tarragona, Spain; CIBER de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Madrid, Spain; Department of Medicine and Surgery, University Rovira I Virgili, Tarragona, Spain
| | - Joan Vendrell
- Department of Endocrinology and Nutrition and Research Unit, University Hospital of Tarragona Joan XXIII, Institut d'Investigació Sanitària Pere Virgili (IISPV), Tarragona, Spain; CIBER de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Madrid, Spain; Department of Medicine and Surgery, University Rovira I Virgili, Tarragona, Spain
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13
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Sun L, Zhang H, Gao P. Metabolic reprogramming and epigenetic modifications on the path to cancer. Protein Cell 2021; 13:877-919. [PMID: 34050894 PMCID: PMC9243210 DOI: 10.1007/s13238-021-00846-7] [Citation(s) in RCA: 174] [Impact Index Per Article: 58.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Accepted: 04/02/2021] [Indexed: 02/07/2023] Open
Abstract
Metabolic rewiring and epigenetic remodeling, which are closely linked and reciprocally regulate each other, are among the well-known cancer hallmarks. Recent evidence suggests that many metabolites serve as substrates or cofactors of chromatin-modifying enzymes as a consequence of the translocation or spatial regionalization of enzymes or metabolites. Various metabolic alterations and epigenetic modifications also reportedly drive immune escape or impede immunosurveillance within certain contexts, playing important roles in tumor progression. In this review, we focus on how metabolic reprogramming of tumor cells and immune cells reshapes epigenetic alterations, in particular the acetylation and methylation of histone proteins and DNA. We also discuss other eminent metabolic modifications such as, succinylation, hydroxybutyrylation, and lactylation, and update the current advances in metabolism- and epigenetic modification-based therapeutic prospects in cancer.
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Affiliation(s)
- Linchong Sun
- Guangzhou First People's Hospital, School of Medicine, Institutes for Life Sciences, South China University of Technology, Guangzhou, 510006, China.
| | - Huafeng Zhang
- The First Affiliated Hospital of USTC, University of Science and Technology of China, Hefei, 230027, China. .,CAS Centre for Excellence in Cell and Molecular Biology, the CAS Key Laboratory of Innate Immunity and Chronic Disease, School of Basic Medical Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, 230027, China.
| | - Ping Gao
- Guangzhou First People's Hospital, School of Medicine, Institutes for Life Sciences, South China University of Technology, Guangzhou, 510006, China. .,School of Biomedical Sciences and Engineering, Guangzhou International Campus, South China University of Technology, Guangzhou, 510006, China. .,Guangzhou Regenerative Medicine and Health Guangdong Laboratory, Guangzhou, 510005, China.
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14
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Tong Y, Guo D, Lin SH, Liang J, Yang D, Ma C, Shao F, Li M, Yu Q, Jiang Y, Li L, Fang J, Yu R, Lu Z. SUCLA2-coupled regulation of GLS succinylation and activity counteracts oxidative stress in tumor cells. Mol Cell 2021; 81:2303-2316.e8. [PMID: 33991485 DOI: 10.1016/j.molcel.2021.04.002] [Citation(s) in RCA: 79] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Revised: 01/15/2021] [Accepted: 04/01/2021] [Indexed: 11/29/2022]
Abstract
Glutaminase regulates glutaminolysis to promote cancer cell proliferation. However, the mechanism underlying glutaminase activity regulation is largely unknown. Here, we demonstrate that kidney-type glutaminase (GLS) is highly expressed in human pancreatic ductal adenocarcinoma (PDAC) specimens with correspondingly upregulated glutamine dependence for PDAC cell proliferation. Upon oxidative stress, the succinyl-coenzyme A (CoA) synthetase ADP-forming subunit β (SUCLA2) phosphorylated by p38 mitogen-activated protein kinase (MAPK) at S79 dissociates from GLS, resulting in enhanced GLS K311 succinylation, oligomerization, and activity. Activated GLS increases glutaminolysis and the production of nicotinamide adenine dinucleotide phosphate (NADPH) and glutathione, thereby counteracting oxidative stress and promoting tumor cell survival and tumor growth in mice. In addition, the levels of SUCLA2 pS79 and GLS K311 succinylation, which were mutually correlated, were positively associated with advanced stages of PDAC and poor prognosis for patients. Our findings reveal critical regulation of GLS by SUCLA2-coupled GLS succinylation regulation and underscore the regulatory role of metabolites in glutaminolysis and PDAC development.
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Affiliation(s)
- Yingying Tong
- The Institute of Cell Metabolism and Diseases, Shanghai Key Laboratory of Pancreatic Disease, Shanghai General Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200080, China; Cancer Center, Beijing Luhe Hospital, Capital Medical University, Beijing 101149, China
| | - Dong Guo
- Department of Hepatobiliary and Pancreatic Surgery and Zhejiang Provincial Key Laboratory of Pancreatic Disease of The First Affiliated Hospital, Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310029, China; Zhejiang University Cancer Center, Hangzhou, Zhejiang 310029, China
| | - Shu-Hai Lin
- State Key Laboratory for Cellular Stress Biology, Innovation Center for Cell Signaling Network, School of Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Jiazhen Liang
- Key Laboratory of Marine Drugs, Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao, Shandong 266003, China
| | - Dianqiang Yang
- State Key Laboratory for Cellular Stress Biology, Innovation Center for Cell Signaling Network, School of Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Chunmin Ma
- The Institute of Cell Metabolism and Diseases, Shanghai Key Laboratory of Pancreatic Disease, Shanghai General Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200080, China
| | - Fei Shao
- The Affiliated Hospital of Qingdao University, Qingdao Cancer Institute, Qingdao, Shandong 266071, China
| | - Min Li
- Department of Hepatobiliary and Pancreatic Surgery and Zhejiang Provincial Key Laboratory of Pancreatic Disease of The First Affiliated Hospital, Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310029, China; Zhejiang University Cancer Center, Hangzhou, Zhejiang 310029, China
| | - Qiujing Yu
- The Institute of Cell Metabolism and Diseases, Shanghai Key Laboratory of Pancreatic Disease, Shanghai General Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200080, China; Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), Department of Immunology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin 300070, China
| | - Yuhui Jiang
- The Institute of Cell Metabolism and Diseases, Shanghai Key Laboratory of Pancreatic Disease, Shanghai General Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200080, China
| | - Lei Li
- The Affiliated Hospital of Qingdao University, Qingdao Cancer Institute, Qingdao, Shandong 266071, China
| | - Jing Fang
- The Affiliated Hospital of Qingdao University, Qingdao Cancer Institute, Qingdao, Shandong 266071, China
| | - Rilei Yu
- Key Laboratory of Marine Drugs, Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao, Shandong 266003, China.
| | - Zhimin Lu
- Department of Hepatobiliary and Pancreatic Surgery and Zhejiang Provincial Key Laboratory of Pancreatic Disease of The First Affiliated Hospital, Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou, Zhejiang 310029, China; Zhejiang University Cancer Center, Hangzhou, Zhejiang 310029, China.
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15
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Sant’Anna-Silva ACB, Perez-Valencia JA, Sciacovelli M, Lalou C, Sarlak S, Tronci L, Nikitopoulou E, Meszaros AT, Frezza C, Rossignol R, Gnaiger E, Klocker H. Succinate Anaplerosis Has an Onco-Driving Potential in Prostate Cancer Cells. Cancers (Basel) 2021; 13:cancers13071727. [PMID: 33917317 PMCID: PMC8038717 DOI: 10.3390/cancers13071727] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 03/23/2021] [Accepted: 04/02/2021] [Indexed: 12/29/2022] Open
Abstract
Simple Summary Depending on the availability of nutrients and increased metabolic demands, tumor cells rearrange their metabolism to survive and, ultimately, proliferate. Here, the authors investigated the effect of succinate, a metabolite of the mitochondrial citric acid cycle, on malignant and non-malignant prostate cells. They analyzed uptake through membrane transporters and intracellular accumulation, which subsequently fuels metabolism and enhances oncogenic properties of the tumor cells. The findings shed light to the metabolic adaptations that prostate tumor cells undergo, providing a better understanding of metabolic rewiring and strategies for therapeutic intervention. Abstract Tumor cells display metabolic alterations when compared to non-transformed cells. These characteristics are crucial for tumor development, maintenance and survival providing energy supplies and molecular precursors. Anaplerosis is the property of replenishing the TCA cycle, the hub of carbon metabolism, participating in the biosynthesis of precursors for building blocks or signaling molecules. In advanced prostate cancer, an upshift of succinate-driven oxidative phosphorylation via mitochondrial Complex II was reported. Here, using untargeted metabolomics, we found succinate accumulation mainly in malignant cells and an anaplerotic effect contributing to biosynthesis, amino acid, and carbon metabolism. Succinate also stimulated oxygen consumption. Malignant prostate cells displayed higher mitochondrial affinity for succinate when compared to non-malignant prostate cells and the succinate-driven accumulation of metabolites induced expression of mitochondrial complex subunits and their activities. Moreover, extracellular succinate stimulated migration, invasion, and colony formation. Several enzymes linked to accumulated metabolites in the malignant cells were found upregulated in tumor tissue datasets, particularly NME1 and SHMT2 mRNA expression. High expression of the two genes was associated with shorter disease-free survival in prostate cancer cohorts. Moreover, in-vitro expression of both genes was enhanced in prostate cancer cells upon succinate stimulation. In conclusion, the data indicate that uptake of succinate from the tumor environment has an anaplerotic effect that enhances the malignant potential of prostate cancer cells.
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Affiliation(s)
- Ana Carolina B. Sant’Anna-Silva
- Daniel Swarovski Research Laboratory, Department of Visceral, Transplant and Thoracic Surgery, Medical University Innsbruck, 6020 Innsbruck, Austria; (A.T.M.); (E.G.)
- Oroboros Instruments GmbH, 6020 Innsbruck, Austria
- Correspondence: (A.C.B.S.-S.); (H.K.)
| | | | - Marco Sciacovelli
- Medical Research Council Cancer Unit, University of Cambridge, Cambridge CB2 0XZ, UK; (M.S.); (L.T.); (E.N.); (C.F.)
| | - Claude Lalou
- Institut National de la Santé Et de la Recherche Médicale (INSERM) U1211, Bordeaux University, 33076 Bordeaux, France; (C.L.); (S.S.); (R.R.)
| | - Saharnaz Sarlak
- Institut National de la Santé Et de la Recherche Médicale (INSERM) U1211, Bordeaux University, 33076 Bordeaux, France; (C.L.); (S.S.); (R.R.)
| | - Laura Tronci
- Medical Research Council Cancer Unit, University of Cambridge, Cambridge CB2 0XZ, UK; (M.S.); (L.T.); (E.N.); (C.F.)
| | - Efterpi Nikitopoulou
- Medical Research Council Cancer Unit, University of Cambridge, Cambridge CB2 0XZ, UK; (M.S.); (L.T.); (E.N.); (C.F.)
| | - Andras T. Meszaros
- Daniel Swarovski Research Laboratory, Department of Visceral, Transplant and Thoracic Surgery, Medical University Innsbruck, 6020 Innsbruck, Austria; (A.T.M.); (E.G.)
| | - Christian Frezza
- Medical Research Council Cancer Unit, University of Cambridge, Cambridge CB2 0XZ, UK; (M.S.); (L.T.); (E.N.); (C.F.)
| | - Rodrigue Rossignol
- Institut National de la Santé Et de la Recherche Médicale (INSERM) U1211, Bordeaux University, 33076 Bordeaux, France; (C.L.); (S.S.); (R.R.)
| | - Erich Gnaiger
- Daniel Swarovski Research Laboratory, Department of Visceral, Transplant and Thoracic Surgery, Medical University Innsbruck, 6020 Innsbruck, Austria; (A.T.M.); (E.G.)
- Oroboros Instruments GmbH, 6020 Innsbruck, Austria
| | - Helmut Klocker
- Department of Surgery, Division of Experimental Urology, University Hospital for Urology, Medical University Innsbruck, 6020 Innsbruck, Austria
- Correspondence: (A.C.B.S.-S.); (H.K.)
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16
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Yang L, Miao S, Zhang J, Wang P, Liu G, Wang J. The growing landscape of succinylation links metabolism and heart disease. Epigenomics 2021; 13:319-333. [PMID: 33605156 DOI: 10.2217/epi-2020-0273] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Post-translational modification of proteins is an important biochemical process that occurs at the protein level. Succinylation is a newly discovered post-translational modification with the hallmark of a significant chemical and structural change. Succinylation has many similarities with other modifications, but succinylation may lead to more functional changes. Although the physiological significance of succinylation has not been well characterized, the lysine succinylation modification shows great potentials during disease processes. The discovery of SIRT5 has made great progress in exploring the role of succinylation in energy metabolism, heart disease and tumorigenesis. In this review, we focus on the discovery of succinylation in organisms and mechanism of succinylation. We are also concerned with the metabolic reactions and heart diseases associated with succinylation.
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Affiliation(s)
- Lanting Yang
- Department of Cardiovascular Surgery, the Affiliated Hospital of Qingdao University, Qingdao 266000, China.,School of Basic Medicine, Qingdao University, Qingdao 266021, China
| | - Shuo Miao
- School of Basic Medicine, Qingdao University, Qingdao 266021, China
| | - Jing Zhang
- School of Basic Medicine, Qingdao University, Qingdao 266021, China
| | - Peiyan Wang
- School of Basic Medicine, Qingdao University, Qingdao 266021, China
| | - Gaoli Liu
- Department of Cardiovascular Surgery, the Affiliated Hospital of Qingdao University, Qingdao 266000, China
| | - Jianxun Wang
- School of Basic Medicine, Qingdao University, Qingdao 266021, China
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17
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Liu M, Huang Y, Xu X, Li X, Alam M, Arunagiri A, Haataja L, Ding L, Wang S, Itkin-Ansari P, Kaufman RJ, Tsai B, Qi L, Arvan P. Normal and defective pathways in biogenesis and maintenance of the insulin storage pool. J Clin Invest 2021; 131:142240. [PMID: 33463547 PMCID: PMC7810482 DOI: 10.1172/jci142240] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Both basal and glucose-stimulated insulin release occur primarily by insulin secretory granule exocytosis from pancreatic β cells, and both are needed to maintain normoglycemia. Loss of insulin-secreting β cells, accompanied by abnormal glucose tolerance, may involve simple exhaustion of insulin reserves (which, by immunostaining, appears as a loss of β cell identity), or β cell dedifferentiation, or β cell death. While various sensing and signaling defects can result in diminished insulin secretion, somewhat less attention has been paid to diabetes risk caused by insufficiency in the biosynthetic generation and maintenance of the total insulin granule storage pool. This Review offers an overview of insulin biosynthesis, beginning with the preproinsulin mRNA (translation and translocation into the ER), proinsulin folding and export from the ER, and delivery via the Golgi complex to secretory granules for conversion to insulin and ultimate hormone storage. All of these steps are needed for generation and maintenance of the total insulin granule pool, and defects in any of these steps may, weakly or strongly, perturb glycemic control. The foregoing considerations have obvious potential relevance to the pathogenesis of type 2 diabetes and some forms of monogenic diabetes; conceivably, several of these concepts might also have implications for β cell failure in type 1 diabetes.
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Affiliation(s)
- Ming Liu
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Yumeng Huang
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Xiaoxi Xu
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Xin Li
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Maroof Alam
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Anoop Arunagiri
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Leena Haataja
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Li Ding
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, China
| | - Shusen Wang
- Organ Transplant Center, Tianjin First Central Hospital, Tianjin, China
| | | | - Randal J. Kaufman
- Degenerative Diseases Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California, USA
| | - Billy Tsai
- Department of Cell and Developmental Biology, and
| | - Ling Qi
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Peter Arvan
- Division of Metabolism, Endocrinology and Diabetes, University of Michigan Medical School, Ann Arbor, Michigan, USA
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18
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Green HLH, Brewer AC. Dysregulation of 2-oxoglutarate-dependent dioxygenases by hyperglycaemia: does this link diabetes and vascular disease? Clin Epigenetics 2020; 12:59. [PMID: 32345373 PMCID: PMC7189706 DOI: 10.1186/s13148-020-00848-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Accepted: 04/08/2020] [Indexed: 02/06/2023] Open
Abstract
The clinical, social and economic burden of cardiovascular disease (CVD) associated with diabetes underscores an urgency for understanding the disease aetiology. Evidence suggests that the hyperglycaemia associated with diabetes is, of itself, causal in the development of endothelial dysfunction (ED) which is recognised to be the critical determinant in the development of CVD. It is further recognised that epigenetic modifications associated with changes in gene expression are causal in both the initiation of ED and the progression to CVD. Understanding whether and how hyperglycaemia induces epigenetic modifications therefore seems crucial in the development of preventative treatments. A mechanistic link between energy metabolism and epigenetic regulation is increasingly becoming explored as key energy metabolites typically serve as substrates or co-factors for epigenetic modifying enzymes. Intriguing examples are the ten-eleven translocation and Jumonji C proteins which facilitate the demethylation of DNA and histones respectively. These are members of the 2-oxoglutarate-dependent dioxygenase superfamily which require the tricarboxylic acid metabolite, α-ketoglutarate and molecular oxygen (O2) as substrates and Fe (II) as a co-factor. An understanding of precisely how the biochemical effects of high glucose exposure impact upon cellular metabolism, O2 availability and cellular redox in endothelial cells (ECs) may therefore elucidate (in part) the mechanistic link between hyperglycaemia and epigenetic modifications causal in ED and CVD. It would also provide significant proof of concept that dysregulation of the epigenetic landscape may be causal rather than consequential in the development of pathology.
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Affiliation(s)
- Hannah L H Green
- School of Cardiovascular Medicine & Sciences, King's College London British Heart Foundation Centre of Research Excellence, London, UK
| | - Alison C Brewer
- School of Cardiovascular Medicine & Sciences, King's College London British Heart Foundation Centre of Research Excellence, London, UK.
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19
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Berdous D, Berney X, Sanchez-Archidona AR, Jan M, Roujeau C, Lopez-Mejia IC, Mynatt R, Thorens B. A genetic screen identifies Crat as a regulator of pancreatic beta-cell insulin secretion. Mol Metab 2020; 37:100993. [PMID: 32298772 PMCID: PMC7225740 DOI: 10.1016/j.molmet.2020.100993] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2020] [Revised: 04/02/2020] [Accepted: 04/02/2020] [Indexed: 11/28/2022] Open
Abstract
Objectives Glucose-stimulated insulin secretion is a critical function in the regulation of glucose homeostasis, and its deregulation is associated with the development of type 2 diabetes. Here, we performed a genetic screen using islets isolated from the BXD panel of advanced recombinant inbred (RI) lines of mice to search for novel regulators of insulin production and secretion. Methods Pancreatic islets were isolated from 36 RI BXD lines and insulin secretion was measured following exposure to 2.8 or 16.7 mM glucose with or without exendin-4. Islets from the same RI lines were used for RNA extraction and transcript profiling. Quantitative trait loci (QTL) mapping was performed for each secretion condition and combined with transcriptome data to prioritize candidate regulatory genes within the identified QTL regions. Functional studies were performed by mRNA silencing or overexpression in MIN6B1 cells and by studying mice and islets with beta-cell-specific gene inactivation. Results Insulin secretion under the 16.7 mM glucose plus exendin-4 condition was mapped significantly to a chromosome 2 QTL. Within this QTL, RNA-Seq data prioritized Crat (carnitine O-acetyl transferase) as a strong candidate regulator of the insulin secretion trait. Silencing Crat expression in MIN6B1 cells reduced insulin content and insulin secretion by ∼30%. Conversely, Crat overexpression enhanced insulin content and secretion by ∼30%. When islets from mice with beta-cell-specific Crat inactivation were exposed to high glucose, they displayed a 30% reduction of insulin content as compared to control islets. We further showed that decreased Crat expression in both MIN6B1 cells and pancreatic islets reduced the oxygen consumption rate in a glucose concentration-dependent manner. Conclusions We identified Crat as a regulator of insulin secretion whose action is mediated by an effect on total cellular insulin content; this effect also depends on the genetic background of the RI mouse lines. These data also show that in the presence of the stimulatory conditions used the insulin secretion rate is directly related to the insulin content. A QTL analysis in BXD mice identifies Crat as a regulator of insulin secretion. Crat regulates insulin content in MIN6B1 cells and pancreatic islets. Crat regulates glucose oxidation in MIN6B1 cells and pancreatic islets. Crat links glucose metabolism to the control of beta-cell insulin content. Insulin content limits insulin secretion in response to high glucose and exendin-4 level.
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Affiliation(s)
- Dassine Berdous
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland.
| | - Xavier Berney
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland.
| | - Ana Rodriguez Sanchez-Archidona
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland; Vital-IT, Swiss Institute of Bioinformatics, 1015 Lausanne, Switzerland.
| | - Maxime Jan
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland.
| | - Clara Roujeau
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland.
| | - Isabel C Lopez-Mejia
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland.
| | - Randall Mynatt
- Pennington Biomedical Research Center, 6400 Perkins Road, Baton Rouge, LA 70808, USA.
| | - Bernard Thorens
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland.
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20
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Sreedhar A, Wiese EK, Hitosugi T. Enzymatic and metabolic regulation of lysine succinylation. Genes Dis 2019; 7:166-171. [PMID: 32215286 PMCID: PMC7083736 DOI: 10.1016/j.gendis.2019.09.011] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Revised: 09/11/2019] [Accepted: 09/27/2019] [Indexed: 12/12/2022] Open
Abstract
Lysine succinylation (Ksucc), defined as a transfer of a succinyl group to a lysine residue of a protein, is a newly identified protein post-translational modification1–3. This chemical modification is reversible, dynamic, and evolutionarily conserved 4 where it has been comprehensively studied in both bacterial and mammalian cells5–7. Numerous proteins involved in the regulation of various cellular and biological processes have been shown to be heavily succinylated5–7. Emerging clinical data provides evidence that dysregulation of Ksucc is correlated with the development of several diseases, including cardiovascular diseases and cancer7–9. Therefore, an in-depth understanding of Ksucc and its regulation is important not only for understanding its physiological function but also for developing drug therapies and targeted agents for these diseases. In this review, we highlight some of the recent advances in understanding the role of Ksucc and desuccinylation under physiological and pathological conditions.
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Affiliation(s)
- Annapoorna Sreedhar
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN, USA.,Division of Oncology Research, Mayo Clinic, Rochester, MN, USA
| | - Elizabeth K Wiese
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN, USA
| | - Taro Hitosugi
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN, USA.,Division of Oncology Research, Mayo Clinic, Rochester, MN, USA
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21
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Effects of Hydroalcoholic Flower Extract of Marigold (Calendula officinalis) on the Biochemical and Histological Parameters in STZ-Induced Diabetic Rats. Jundishapur J Nat Pharm Prod 2019. [DOI: 10.5812/jjnpp.55456] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
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22
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Boland BB, Rhodes CJ, Grimsby JS. The dynamic plasticity of insulin production in β-cells. Mol Metab 2017; 6:958-973. [PMID: 28951821 PMCID: PMC5605729 DOI: 10.1016/j.molmet.2017.04.010] [Citation(s) in RCA: 112] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Revised: 04/27/2017] [Accepted: 04/28/2017] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Although the insulin-producing pancreatic β-cells are quite capable of adapting to both acute and chronic changes in metabolic demand, persistently high demand for insulin will ultimately lead to their progressive dysfunction and eventual loss. Recent and historical studies highlight the importance of 'resting' the β-cell as a means of preserving functional β-cell mass. SCOPE OF REVIEW We provide experimental evidence to highlight the remarkable plasticity for insulin production and secretion by the pancreatic β-cell alongside some clinical evidence that supports leveraging this unique ability to preserve β-cell function. MAJOR CONCLUSIONS Treatment strategies for type 2 diabetes mellitus (T2DM) targeted towards reducing the systemic metabolic burden, rather than demanding greater insulin production from an already beleaguered β-cell, should be emphasized to maintain endogenous insulin secretory function and delay the progression of T2DM.
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Key Words
- ATF6, Activating Transcription Factor 6
- CHOP, CCAAT/Enhancer-Binding Homologous Protein
- EPAC, Exchange Factor Directly Activated by cAMP
- EROβ1, ER-resident oxidoreductase β1
- GIP, Gastric Inhibitory Polypeptide
- GLP-1, Glucagon-like Peptide 1
- GLUT2, Glucose Transporter 2
- GSIS, Glucose Stimulated Insulin Secretion
- IREα, Inositol Requiring Enzyme α
- Insulin production
- NEFA, Non-esterified Fatty Acid
- PERK, Protein Kinase RNA-like Endoplasmic Reticulum Kinase
- PKA, Protein Kinase A
- PKC, Protein Kinase C
- PLC, Phospholipase C
- ROS, Reactive Oxygen Species
- SNAP-25, Soluble NSF Attachment Protein 25
- SNARE, Soluble NSF Attachment Protein Receptor
- STZ, Streptozotocin
- T2DM
- T2DM, Type 2 Diabetes Mellitus
- TRP, Transient Receptor Potential
- VAMP-2, Vehicle Associated Membrane Protein 2
- VDCC, Voltage Dependent Calcium Channel
- mTORC1, Mammalian Target of Rapamycin 1
- nH, Hill coefficient
- β-cell rest
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Affiliation(s)
- Brandon B. Boland
- MedImmune, Cardiovascular and Metabolic Disease Research, 1 MedImmune Way, Gaithersburg, MD 20878, USA
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23
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Abstract
The pancreatic β-cell secretes insulin in response to elevated plasma glucose. This review applies an external bioenergetic critique to the central processes of glucose-stimulated insulin secretion, including glycolytic and mitochondrial metabolism, the cytosolic adenine nucleotide pool, and its interaction with plasma membrane ion channels. The control mechanisms responsible for the unique responsiveness of the cell to glucose availability are discussed from bioenergetic and metabolic control standpoints. The concept of coupling factor facilitation of secretion is critiqued, and an attempt is made to unravel the bioenergetic basis of the oscillatory mechanisms controlling secretion. The need to consider the physiological constraints operating in the intact cell is emphasized throughout. The aim is to provide a coherent pathway through an extensive, complex, and sometimes bewildering literature, particularly for those unfamiliar with the field.
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Affiliation(s)
- David G Nicholls
- Buck Institute for Research on Aging, Novato, California; and Department of Clinical Sciences, Unit of Molecular Metabolism, Lund University Diabetes Centre, Malmo, Sweden
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De Marchi U, Hermant A, Thevenet J, Ratinaud Y, Santo-Domingo J, Barron D, Wiederkehr A. A novel ATP-synthase-independent mechanism coupling mitochondrial activation to exocytosis in insulin-secreting cells. J Cell Sci 2017; 130:1929-1939. [PMID: 28404787 DOI: 10.1242/jcs.200741] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Accepted: 04/11/2017] [Indexed: 12/16/2022] Open
Abstract
Pancreatic β-cells sense glucose, promoting insulin secretion. Glucose sensing requires the sequential stimulation of glycolysis, mitochondrial metabolism and Ca2+ entry. To elucidate how mitochondrial activation in β-cells contributes to insulin secretion, we compared the effects of glucose and the mitochondrial substrate methylsuccinate in the INS-1E insulin-secreting cell line at the respective concentrations at which they maximally activate mitochondrial respiration. Both substrates induced insulin secretion with distinct respiratory profiles, mitochondrial hyperpolarization, NADH production and ATP-to-ADP ratios. In contrast to glucose, methylsuccinate failed to induce large [Ca2+] rises and exocytosis proceeded largely independently of mitochondrial ATP synthesis. Both glucose- and methylsuccinate-induced secretion was blocked by diazoxide, indicating that Ca2+ is required for exocytosis. Dynamic assessment of the redox state of mitochondrial thiols revealed a less marked reduction in response to methylsuccinate than with glucose. Our results demonstrate that insulin exocytosis can be promoted by two distinct mechanisms one of which is dependent on mitochondrial ATP synthesis and large Ca2+ transients, and one of which is independent of mitochondrial ATP synthesis and relies on small Ca2+ signals. We propose that the combined effects of Ca2+ and redox reactions can trigger insulin secretion by these two mechanisms.
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Affiliation(s)
- Umberto De Marchi
- Mitochondrial Function, Nestlé Institute of Health Sciences, EPFL Innovation Park, Building G, Lausanne CH-1015, Switzerland
| | - Aurelie Hermant
- Mitochondrial Function, Nestlé Institute of Health Sciences, EPFL Innovation Park, Building G, Lausanne CH-1015, Switzerland
| | - Jonathan Thevenet
- Mitochondrial Function, Nestlé Institute of Health Sciences, EPFL Innovation Park, Building G, Lausanne CH-1015, Switzerland
| | - Yann Ratinaud
- Natural Bioactives and screening, Nestlé Institute of Health Sciences, EPFL Innovation Park, Building H, Lausanne CH-1015, Switzerland
| | - Jaime Santo-Domingo
- Mitochondrial Function, Nestlé Institute of Health Sciences, EPFL Innovation Park, Building G, Lausanne CH-1015, Switzerland
| | - Denis Barron
- Natural Bioactives and screening, Nestlé Institute of Health Sciences, EPFL Innovation Park, Building H, Lausanne CH-1015, Switzerland
| | - Andreas Wiederkehr
- Mitochondrial Function, Nestlé Institute of Health Sciences, EPFL Innovation Park, Building G, Lausanne CH-1015, Switzerland
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Donti TR, Masand R, Scott DA, Craigen WJ, Graham BH. Expanding the phenotypic spectrum of Succinyl-CoA ligase deficiency through functional validation of a new SUCLG1 variant. Mol Genet Metab 2016; 119:68-74. [PMID: 27484306 PMCID: PMC5031536 DOI: 10.1016/j.ymgme.2016.07.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Revised: 07/17/2016] [Accepted: 07/18/2016] [Indexed: 11/21/2022]
Abstract
Deficiency of the TCA cycle enzyme Succinyl-CoA Synthetase/Ligase (SCS), due to pathogenic variants in subunits encoded by SUCLG1 and SUCLA2, causes mitochondrial encephalomyopathy, methylmalonic acidemia, and mitochondrial DNA (mtDNA) depletion. In this study, we report an 11year old patient who presented with truncal ataxia, chorea, hypotonia, bilateral sensorineural hearing loss and preserved cognition. Whole exome sequencing identified a heterozygous known pathogenic variant and a heterozygous novel missense variant of uncertain clinical significance (VUS) in SUCLG1. To validate the suspected pathogenicity of the novel VUS, molecular and biochemical analyses were performed using primary skin fibroblasts from the patient. The patient's cells lack the SUCLG1 protein, with significantly reduced levels of SUCLA2 and SUCLG2 protein. This leads to essentially undetectable SCS enzyme activity, mtDNA depletion, and cellular respiration defects. These abnormal phenotypes are rescued upon ectopic expression of wild-type SUCLG1 in the patient's fibroblasts, thus functionally confirming the pathogenic nature of the SUCLG1 VUS identified in this patient and expanding the phenotypic spectrum for SUCLG1 deficiency.
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Affiliation(s)
- Taraka R Donti
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Ruchi Masand
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Daryl A Scott
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA; Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX, USA
| | - William J Craigen
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA
| | - Brett H Graham
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA.
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26
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Two transgenic mouse models for β-subunit components of succinate-CoA ligase yielding pleiotropic metabolic alterations. Biochem J 2016; 473:3463-3485. [PMID: 27496549 PMCID: PMC5126846 DOI: 10.1042/bcj20160594] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Accepted: 08/05/2016] [Indexed: 12/14/2022]
Abstract
Succinate-CoA ligase (SUCL) is a heterodimer enzyme composed of Suclg1 α-subunit and a substrate-specific Sucla2 or Suclg2 β-subunit yielding ATP or GTP, respectively. In humans, the deficiency of this enzyme leads to encephalomyopathy with or without methylmalonyl aciduria, in addition to resulting in mitochondrial DNA depletion. We generated mice lacking either one Sucla2 or Suclg2 allele. Sucla2 heterozygote mice exhibited tissue- and age-dependent decreases in Sucla2 expression associated with decreases in ATP-forming activity, but rebound increases in cardiac Suclg2 expression and GTP-forming activity. Bioenergetic parameters including substrate-level phosphorylation (SLP) were not different between wild-type and Sucla2 heterozygote mice unless a submaximal pharmacological inhibition of SUCL was concomitantly present. mtDNA contents were moderately decreased, but blood carnitine esters were significantly elevated. Suclg2 heterozygote mice exhibited decreases in Suclg2 expression but no rebound increases in Sucla2 expression or changes in bioenergetic parameters. Surprisingly, deletion of one Suclg2 allele in Sucla2 heterozygote mice still led to a rebound but protracted increase in Suclg2 expression, yielding double heterozygote mice with no alterations in GTP-forming activity or SLP, but more pronounced changes in mtDNA content and blood carnitine esters, and an increase in succinate dehydrogenase activity. We conclude that a partial reduction in Sucla2 elicits rebound increases in Suclg2 expression, which is sufficiently dominant to overcome even a concomitant deletion of one Suclg2 allele, pleiotropically affecting metabolic pathways associated with SUCL. These results as well as the availability of the transgenic mouse colonies will be of value in understanding SUCL deficiency.
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27
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Once and for all, LXRα and LXRβ are gatekeepers of the endocrine system. Mol Aspects Med 2016; 49:31-46. [DOI: 10.1016/j.mam.2016.04.001] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Revised: 03/08/2016] [Accepted: 04/10/2016] [Indexed: 01/08/2023]
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28
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Yi NY, He Q, Caligan TB, Smith GR, Forsberg LJ, Brenman JE, Sexton JZ. Development of a Cell-Based Fluorescence Polarization Biosensor Using Preproinsulin to Identify Compounds That Alter Insulin Granule Dynamics. Assay Drug Dev Technol 2015; 13:558-69. [PMID: 26505612 PMCID: PMC4955689 DOI: 10.1089/adt.2015.665] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Diabetes currently affects 9.3% of the U.S. population totaling $245 billion annually in U.S. direct and indirect healthcare costs. Current therapies for diabetes are limited in their ability to control blood glucose and/or enhance insulin sensitivity. Therefore, innovative and efficacious therapies for diabetes are urgently needed. Herein we describe a fluorescent insulin reporter system (preproinsulin-mCherry, PPI-mCherry) that tracks live-cell insulin dynamics and secretion in pancreatic β-cells with utility for high-content assessment of real-time insulin dynamics. Additionally, we report a new modality for sensing insulin granule packaging in conventional high-throughput screening (HTS), using a hybrid cell-based fluorescence polarization (FP)/internal FRET biosensor using the PPI-mCherry reporter system. We observed that bafilomycin, a vacuolar H(+) ATPase inhibitor and inhibitor of insulin granule formation, significantly increased mCherry FP in INS-1 cells with PPI-mCherry. Partial least squares regression analysis demonstrated that an increase of FP by bafilomycin is significantly correlated with a decrease in granularity of PPI-mCherry signal in the cells. The increased FP by bafilomycin is due to inhibition of self-Förster resonant energy transfer (homo-FRET) caused by the increased mCherry intermolecular distance. FP substantially decreases when insulin is tightly packaged in the granules, and the homo-FRET decreases when insulin granule packaging is inhibited, resulting in increased FP. We performed pilot HTS of 1782 FDA-approved small molecules and natural products from Prestwick and Enzo chemical libraries resulting in an overall Z'-factor of 0.52 ± 0.03, indicating the suitability of this biosensor for HTS. This novel biosensor enables live-cell assessment of protein-protein interaction/protein aggregation in live cells and is compatible with conventional FP plate readers.
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Affiliation(s)
- Na Young Yi
- Biomanufacturing Research Institute and Technology Enterprise, Department of Pharmaceutical Sciences, North Carolina Central University, Durham, North Carolina
| | - Qingping He
- Biomanufacturing Research Institute and Technology Enterprise, Department of Pharmaceutical Sciences, North Carolina Central University, Durham, North Carolina
| | - Thomas B. Caligan
- Biomanufacturing Research Institute and Technology Enterprise, Department of Pharmaceutical Sciences, North Carolina Central University, Durham, North Carolina
| | - Ginger R. Smith
- Biomanufacturing Research Institute and Technology Enterprise, Department of Pharmaceutical Sciences, North Carolina Central University, Durham, North Carolina
| | - Lawrence J. Forsberg
- The Neuroscience Center and Department of Cell Biology & Physiology, UNC Chapel Hill School of Medicine, Chapel Hill, North Carolina
| | - Jay E. Brenman
- The Neuroscience Center and Department of Cell Biology & Physiology, UNC Chapel Hill School of Medicine, Chapel Hill, North Carolina
| | - Jonathan Z. Sexton
- Biomanufacturing Research Institute and Technology Enterprise, Department of Pharmaceutical Sciences, North Carolina Central University, Durham, North Carolina
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29
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Nath AK, Ryu JH, Jin YN, Roberts LD, Dejam A, Gerszten RE, Peterson RT. PTPMT1 Inhibition Lowers Glucose through Succinate Dehydrogenase Phosphorylation. Cell Rep 2015; 10:694-701. [PMID: 25660020 DOI: 10.1016/j.celrep.2015.01.010] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2014] [Revised: 12/10/2014] [Accepted: 12/31/2014] [Indexed: 01/22/2023] Open
Abstract
Virtually all organisms seek to maximize fitness by matching fuel availability with energy expenditure. In vertebrates, glucose homeostasis is central to this process, with glucose levels finely tuned to match changing energy requirements. To discover new pathways regulating glucose levels in vivo, we performed a large-scale chemical screen in live zebrafish and identified the small molecule alexidine as a potent glucose-lowering agent. We found that alexidine inhibits the PTEN-like mitochondrial phosphatase PTPMT1 and that other pharmacological and genetic means of inactivating PTPMT1 also decrease glucose levels in zebrafish. Mutation of ptpmt1 eliminates the effect of alexidine, further confirming it as the glucose-lowering target of alexidine. We then identified succinate dehydrogenase (SDH) as a substrate of PTPMT1. Inactivation of PTPMT1 causes hyperphosphorylation and activation of SDH, providing a possible mechanism by which PTPMT1 coordinates glucose homeostasis. Therefore, PTPMT1 appears to be an important regulator of SDH phosphorylation status and glucose concentration.
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Affiliation(s)
- Anjali K Nath
- Cardiovascular Research Center and Division of Cardiology, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA; Broad Institute, Cambridge, MA 02142, USA.
| | - Justine H Ryu
- Cardiovascular Research Center and Division of Cardiology, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA; Broad Institute, Cambridge, MA 02142, USA
| | - Youngnam N Jin
- Cardiovascular Research Center and Division of Cardiology, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA; Broad Institute, Cambridge, MA 02142, USA
| | - Lee D Roberts
- Cardiovascular Research Center and Division of Cardiology, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA; Broad Institute, Cambridge, MA 02142, USA
| | - Andre Dejam
- Cardiovascular Research Center and Division of Cardiology, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA; Broad Institute, Cambridge, MA 02142, USA
| | - Robert E Gerszten
- Cardiovascular Research Center and Division of Cardiology, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA; Broad Institute, Cambridge, MA 02142, USA
| | - Randall T Peterson
- Cardiovascular Research Center and Division of Cardiology, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, USA; Broad Institute, Cambridge, MA 02142, USA.
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Boland BB, Alarcón C, Ali A, Rhodes CJ. Monomethylated-adenines potentiate glucose-induced insulin production and secretion via inhibition of phosphodiesterase activity in rat pancreatic islets. Islets 2015; 7:e1073435. [PMID: 26404841 PMCID: PMC4878263 DOI: 10.1080/19382014.2015.1073435] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Monomethyladenines have effects on DNA repair, G-protein-coupled receptor antagonism and autophagy. In islet ß-cells, 3-methyladenine (3-MA) has been implicated in DNA-repair and autophagy, but its mechanism of action is unclear. Here, the effect of monomethylated adenines was examined in rat islets. 3-MA, N6-methyladenine (N6-MA) and 9-methyladenine (9-MA), but not 1- or 7-monomethylated adenines, specifically potentiated glucose-induced insulin secretion (3-4 fold; p ≤ 0.05) and proinsulin biosynthesis (∼2-fold; p ≤ 0.05). Using 3-MA as a 'model' monomethyladenine, it was found that 3-MA augmented [cAMP]i accumulation (2-3 fold; p ≤ 0.05) in islets within 5 minutes. The 3-, N6- and 9-MA also enhanced glucose-induced phosphorylation of the cAMP/protein kinase-A (PKA) substrate cAMP-response element binding protein (CREB). Treatment of islets with pertussis or cholera toxin indicated 3-MA mediated elevation of [cAMP]i was not mediated via G-protein-coupled receptors. Also, 3-MA did not compete with 9-cyclopentyladenine (9-CPA) for adenylate cyclase inhibition, but did for the pan-inhibitor of phosphodiesterase (PDE), 3-isobutyl-1-methylxanthine (IBMX). Competitive inhibition experiments with PDE-isoform specific inhibitors suggested 3-MA to have a preference for PDE4 in islet ß-cells, but this was likely reflective of PDE4 being the most abundant PDE isoform in ß-cells. In vitro enzyme assays indicated that 3-, N6- and 9-MA were capable of inhibiting most PDE isoforms found in ß-cells. Thus, in addition to known inhibition of phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3'K)/m Target of Rapamycin (mTOR) signaling, 3-MA also acts as a pan-phosphodiesterase inhibitor in pancreatic ß-cells to elevate [cAMP]i and then potentiate glucose-induced insulin secretion and production in parallel.
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Affiliation(s)
- Brandon B Boland
- The Kovler Diabetes Center; Department of Medicine; Section on Endocrinology, Diabetes & Metabolism; The University of Chicago; Chicago, IL USA
| | - Cristina Alarcón
- The Kovler Diabetes Center; Department of Medicine; Section on Endocrinology, Diabetes & Metabolism; The University of Chicago; Chicago, IL USA
| | - Almas Ali
- The Kovler Diabetes Center; Department of Medicine; Section on Endocrinology, Diabetes & Metabolism; The University of Chicago; Chicago, IL USA
| | - Christopher J Rhodes
- The Kovler Diabetes Center; Department of Medicine; Section on Endocrinology, Diabetes & Metabolism; The University of Chicago; Chicago, IL USA
- Correspondence to: Christopher J Rhodes PhD;
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Modi H, Cornu M, Thorens B. Glutamine stimulates biosynthesis and secretion of insulin-like growth factor 2 (IGF2), an autocrine regulator of beta cell mass and function. J Biol Chem 2014; 289:31972-31982. [PMID: 25271169 DOI: 10.1074/jbc.m114.587733] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
IGF2 is an autocrine ligand for the beta cell IGF1R receptor and GLP-1 increases the activity of this autocrine loop by enhancing IGF1R expression, a mechanism that mediates the trophic effects of GLP-1 on beta cell mass and function. Here, we investigated the regulation of IGF2 biosynthesis and secretion. We showed that glutamine rapidly and strongly induced IGF2 mRNA translation using reporter constructs transduced in MIN6 cells and primary islet cells. This was followed by rapid secretion of IGF2 via the regulated pathway, as revealed by the presence of mature IGF2 in insulin granule fractions and by inhibition of secretion by nimodipine and diazoxide. When maximally stimulated by glutamine, the amount of secreted IGF2 rapidly exceeded its initial intracellular pool and tolbutamide, and high K(+) increased IGF2 secretion only marginally. This indicates that the intracellular pool of IGF2 is small and that sustained secretion requires de novo synthesis. The stimulatory effect of glutamine necessitates its metabolism but not mTOR activation. Finally, exposure of insulinomas or beta cells to glutamine induced Akt phosphorylation, an effect that was dependent on IGF2 secretion, and reduced cytokine-induced apoptosis. Thus, glutamine controls the activity of the beta cell IGF2/IGF1R autocrine loop by increasing the biosynthesis and secretion of IGF2. This autocrine loop can thus integrate changes in feeding and metabolic state to adapt beta cell mass and function.
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Affiliation(s)
- Honey Modi
- Center for Integrative Genomics, University of Lausanne, CH-1015 Lausanne, Switzerland
| | - Marion Cornu
- Center for Integrative Genomics, University of Lausanne, CH-1015 Lausanne, Switzerland
| | - Bernard Thorens
- Center for Integrative Genomics, University of Lausanne, CH-1015 Lausanne, Switzerland.
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Antidiabetic effect of Sida cordata in alloxan induced diabetic rats. BIOMED RESEARCH INTERNATIONAL 2014; 2014:671294. [PMID: 25114914 PMCID: PMC4119905 DOI: 10.1155/2014/671294] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Revised: 05/26/2014] [Accepted: 06/13/2014] [Indexed: 02/06/2023]
Abstract
Medicinal plants are efficient ameliorator of oxidative stress associated with diabetes mellitus. In this study, ethyl acetate fraction (SCEE) of Sida cordata was investigated for scientific validation of its folk use in diabetes. Antidiabetic effect of SCEE was confirmed by antihyperglycemic activity in normal glucose loaded and diabetic glucose loaded animals as well as normal off feed animals. Confirmation of antidiabetic activity and toxicity ameliorative role of S. cordata was investigated in a chronic multiple dose treatment study of fifteen days. A single dose of alloxan (120 mg/kg) produced a decrease in insulin level, hyperglycemia, elevated total lipids, triglycerides, and cholesterol and decreased the high-density lipoproteins. Concurrent with these changes, there was an increase in the concentration of lipid peroxidation (TBARS), H2O2, and nitrite in pancreas, liver, and testis. This oxidative stress was related to a decrease in glutathione content (GSH) and antioxidant enzymes. Administration of SCEE for 15 days after diabetes induction ameliorated hyperglycemia, restored lipid profile, blunted the increase in TBARS, H2O2, and nitrite content, and stimulated the GSH production in the organs of alloxan-treated rats. We suggested that SCEE could be used as antidiabetic component in case of diabetes mellitus. This may be related to its antioxidative properties.
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Marden JH. Nature's inordinate fondness for metabolic enzymes: why metabolic enzyme loci are so frequently targets of selection. Mol Ecol 2013; 22:5743-64. [PMID: 24106889 DOI: 10.1111/mec.12534] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2013] [Revised: 09/11/2013] [Accepted: 09/17/2013] [Indexed: 01/01/2023]
Abstract
Metabolic enzyme loci were some of the first genes accessible for molecular evolution and ecology research. New technologies now make the whole genome, transcriptome or proteome readily accessible, allowing unbiased scans for loci exhibiting significant differences in allele frequency or expression level and associated with phenotypes and/or responses to natural selection. With surprising frequency and in many cases in proportions greater than chance relative to other genes, glycolysis and TCA cycle enzyme loci appear among the genes with significant associations in these studies. Hence, there is an ongoing need to understand the basis for fitness effects of metabolic enzyme polymorphisms. Allele-specific effects on the binding affinity and catalytic rate of individual enzymes are well known, but often of uncertain significance because metabolic control theory and in vivo studies indicate that many individual metabolic enzymes do not affect pathway flux rate. I review research, so far little used in evolutionary biology, showing that metabolic enzyme substrates affect signalling pathways that regulate cell and organismal biology, and that these enzymes have moonlighting functions. To date there is little knowledge of how alleles in natural populations affect these phenotypes. I discuss an example in which alleles of a TCA enzyme locus associate with differences in a signalling pathway and development, organismal performance, and ecological dynamics. Ultimately, understanding how metabolic enzyme polymorphisms map to phenotypes and fitness remains a compelling and ongoing need for gaining robust knowledge of ecological and evolutionary processes.
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Affiliation(s)
- James H Marden
- Department of Biology, Pennsylvania State University, University Park, PA, 16802, USA
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Kiss G, Konrad C, Doczi J, Starkov AA, Kawamata H, Manfredi G, Zhang SF, Gibson GE, Beal MF, Adam-Vizi V, Chinopoulos C. The negative impact of α-ketoglutarate dehydrogenase complex deficiency on matrix substrate-level phosphorylation. FASEB J 2013; 27:2392-406. [PMID: 23475850 DOI: 10.1096/fj.12-220202] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
A decline in α-ketoglutarate dehydrogenase complex (KGDHC) activity has been associated with neurodegeneration. Provision of succinyl-CoA by KGDHC is essential for generation of matrix ATP (or GTP) by substrate-level phosphorylation catalyzed by succinyl-CoA ligase. Here, we demonstrate ATP consumption in respiration-impaired isolated and in situ neuronal somal mitochondria from transgenic mice with a deficiency of either dihydrolipoyl succinyltransferase (DLST) or dihydrolipoyl dehydrogenase (DLD) that exhibit a 20-48% decrease in KGDHC activity. Import of ATP into the mitochondrial matrix of transgenic mice was attributed to a shift in the reversal potential of the adenine nucleotide translocase toward more negative values due to diminished matrix substrate-level phosphorylation, which causes the translocase to reverse prematurely. Immunoreactivity of all three subunits of succinyl-CoA ligase and maximal enzymatic activity were unaffected in transgenic mice as compared to wild-type littermates. Therefore, decreased matrix substrate-level phosphorylation was due to diminished provision of succinyl-CoA. These results were corroborated further by the finding that mitochondria from wild-type mice respiring on substrates supporting substrate-level phosphorylation exhibited ~30% higher ADP-ATP exchange rates compared to those obtained from DLST(+/-) or DLD(+/-) littermates. We propose that KGDHC-associated pathologies are a consequence of the inability of respiration-impaired mitochondria to rely on "in-house" mitochondrial ATP reserves.
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Affiliation(s)
- Gergely Kiss
- Department of Medical Biochemistry, Semmelweis University, Budapest, Hungary
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Abstract
The kinetic mechanism of SCS [succinyl-CoA (coenzyme A) synthetase], which participates in the TCA (tricarboxylic acid) cycle, ketone body metabolism and haem biosynthesis, has not been fully characterized. Namely, a representative catalytic mechanism and associated kinetic parameters that can explain data on the enzyme-catalysed reaction kinetics have not been established. To determine an accurate model, a set of putative mechanisms of SCS, proposed by previous researchers, were tested against experimental data (from previous publication) on SCS derived from porcine myocardium. Based on comparisons between model simulation and the experimental data, an ordered ter–ter mechanism with dead-end product inhibition of succinate against succinyl-CoA is determined to be the best candidate mechanism. A thermodynamically constrained set of parameter values is identified for this candidate mechanism.
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Bensellam M, Laybutt DR, Jonas JC. The molecular mechanisms of pancreatic β-cell glucotoxicity: recent findings and future research directions. Mol Cell Endocrinol 2012; 364:1-27. [PMID: 22885162 DOI: 10.1016/j.mce.2012.08.003] [Citation(s) in RCA: 208] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Revised: 07/11/2012] [Accepted: 08/01/2012] [Indexed: 02/06/2023]
Abstract
It is well established that regular physiological stimulation by glucose plays a crucial role in the maintenance of the β-cell differentiated phenotype. In contrast, prolonged or repeated exposure to elevated glucose concentrations both in vitro and in vivo exerts deleterious or toxic effects on the β-cell phenotype, a concept termed as glucotoxicity. Evidence indicates that the latter may greatly contribute to the pathogenesis of type 2 diabetes. Through the activation of several mechanisms and signaling pathways, high glucose levels exert deleterious effects on β-cell function and survival and thereby, lead to the worsening of the disease over time. While the role of high glucose-induced β-cell overstimulation, oxidative stress, excessive Unfolded Protein Response (UPR) activation, and loss of differentiation in the alteration of the β-cell phenotype is well ascertained, at least in vitro and in animal models of type 2 diabetes, the role of other mechanisms such as inflammation, O-GlcNacylation, PKC activation, and amyloidogenesis requires further confirmation. On the other hand, protein glycation is an emerging mechanism that may play an important role in the glucotoxic deterioration of the β-cell phenotype. Finally, our recent evidence suggests that hypoxia may also be a new mechanism of β-cell glucotoxicity. Deciphering these molecular mechanisms of β-cell glucotoxicity is a mandatory first step toward the development of therapeutic strategies to protect β-cells and improve the functional β-cell mass in type 2 diabetes.
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Affiliation(s)
- Mohammed Bensellam
- Université catholique de Louvain, Institut de recherche expérimentale et clinique, Pôle d'endocrinologie, diabète et nutrition, Brussels, Belgium
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Impairment of Proinsulin Processing in β-Cells Exposed to Saturated Free Fatty Acid Is Dependent on Uncoupling Protein-2 Expression. Can J Diabetes 2012. [DOI: 10.1016/j.jcjd.2012.06.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Fonseca SG, Urano F, Weir GC, Gromada J, Burcin M. Wolfram syndrome 1 and adenylyl cyclase 8 interact at the plasma membrane to regulate insulin production and secretion. Nat Cell Biol 2012; 14:1105-12. [PMID: 22983116 PMCID: PMC3589109 DOI: 10.1038/ncb2578] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2012] [Accepted: 08/10/2012] [Indexed: 01/14/2023]
Abstract
Endoplasmic reticulum (ER) stress causes pancreatic β-cell dysfunction and contributes to β-cell loss and the progression of type 2 diabetes. Wolfram syndrome 1 (WFS1) has been shown to be an important regulator of the ER stress signalling pathway; however, its role in β-cell function remains unclear. Here we provide evidence that WFS1 is essential for glucose- and glucagon-like peptide 1 (GLP-1)-stimulated cyclic AMP production and regulation of insulin biosynthesis and secretion. Stimulation with glucose causes WFS1 translocation from the ER to the plasma membrane, where it forms a complex with adenylyl cyclase 8 (AC8), an essential cAMP-generating enzyme in the β-cell that integrates glucose and GLP-1 signalling. ER stress and mutant WFS1 inhibit complex formation and activation of AC8, reducing cAMP synthesis and insulin secretion. These findings reveal that an ER-stress-related protein has a distinct role outside the ER regulating both insulin biosynthesis and secretion. The reduction of WFS1 protein on the plasma membrane during ER stress is a contributing factor for β-cell dysfunction and progression of type 2 diabetes.
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Affiliation(s)
- Sonya G Fonseca
- Cardiovascular and Metabolism Disease Area, Novartis Institutes for BioMedical Research, Cambridge, Massachusetts 02139, USA.
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Role of mitochondria in beta-cell function and dysfunction. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2010; 654:193-216. [PMID: 20217499 DOI: 10.1007/978-90-481-3271-3_9] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Pancreatic beta-cells are poised to sense glucose and other nutrient secretagogues to regulate insulin exocytosis, thereby maintaining glucose homeostasis. This process requires translation of metabolic substrates into intracellular messengers recognized by the exocytotic machinery. Central to this metabolism-secretion coupling, mitochondria integrate and generate metabolic signals, thereby connecting glucose recognition to insulin exocytosis. In response to a glucose rise, nucleotides and metabolites are generated by mitochondria and participate, together with cytosolic calcium, to the stimulation of insulin release. This review describes the mitochondrion-dependent pathways of regulated insulin secretion. Mitochondrial defects, such as mutations and reactive oxygen species production, are discussed in the context of beta-cell failure that may participate to the etiology of diabetes.
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Insulin release, peripheral insulin resistance and muscle function in protein malnutrition: a role of tricarboxylic acid cycle anaplerosis. Br J Nutr 2009; 103:1237-50. [DOI: 10.1017/s0007114509993060] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Pancreatic β-cells and skeletal muscle act in a synergic way in the control of systemic glucose homeostasis. Several pyruvate-dependent and -independent shuttles enhance tricarboxylic acid cycle intermediate (TACI) anaplerosis and increase β-cell ATP:ADP ratio, triggering insulin exocytotic mechanisms. In addition, mitochondrial TACI cataplerosis gives rise to the so-called metabolic coupling factors, which are also related to insulin release. Peripheral insulin resistance seems to be related to skeletal muscle fatty acid (FA) accumulation and oxidation imbalance. In this sense, exercise has been shown to enhance skeletal muscle TACI anaplerosis, increasing FA oxidation and by this manner restores insulin sensitivity. Protein malnutrition reduces β-cell insulin synthesis, release and peripheral sensitivity. Despite little available data concerning mitochondrial metabolism under protein malnutrition, evidence points towards reduced β-cell and skeletal muscle mitochondrial capacity. The observed decrease in insulin synthesis and release may reflect reduced anaplerotic and cataplerotic capacity. Furthermore, insulin release is tightly coupled to ATP:ADP rise which in turn is related to TACI anaplerosis. The effect of protein malnutrition upon peripheral insulin resistance is time-dependent and directly related to FA oxidation capacity. In contrast to β-cells, TACI anaplerosis and cataplerosis pathways in skeletal muscle seem to control FA oxidation and regulate insulin resistance.
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Rai PK, Chatterji S, Rai NK, Rai AK, Bicanic D, Watal G. The Glycemic Elemental Profile of Trichosanthes dioica: A LIBS-Based Study. FOOD BIOPHYS 2009. [DOI: 10.1007/s11483-009-9139-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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42
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Fonseca SG, Burcin M, Gromada J, Urano F. Endoplasmic reticulum stress in beta-cells and development of diabetes. Curr Opin Pharmacol 2009; 9:763-70. [PMID: 19665428 DOI: 10.1016/j.coph.2009.07.003] [Citation(s) in RCA: 123] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2009] [Revised: 06/29/2009] [Accepted: 07/08/2009] [Indexed: 01/09/2023]
Abstract
The endoplasmic reticulum (ER) is a cellular compartment responsible for multiple important cellular functions including the biosynthesis and folding of newly synthesized proteins destined for secretion, such as insulin. A myriad of pathological and physiological factors perturb ER function and cause dysregulation of ER homeostasis, leading to ER stress. ER stress elicits a signaling cascade to mitigate stress, the unfolded protein response (UPR). As long as the UPR can relieve stress, cells can produce the proper amount of proteins and maintain ER homeostasis. If the UPR, however, fails to maintain ER homeostasis, cells will undergo apoptosis. Activation of the UPR is critical to the survival of insulin-producing pancreatic beta-cells with high secretory protein production. Any disruption of ER homeostasis in beta-cells can lead to cell death and contribute to the pathogenesis of diabetes. There are several models of ER-stress-mediated diabetes. In this review, we outline the underlying molecular mechanisms of ER-stress-mediated beta-cell dysfunction and death during the progression of diabetes.
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Affiliation(s)
- Sonya G Fonseca
- Cardiovascular and Metabolism Division, Novartis Institutes for Biomedical Research, Inc., Cambridge, MA 02139, USA
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43
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Khoo S, Gibson TB, Arnette D, Lawrence M, January B, McGlynn K, Vanderbilt CA, Griffen SC, German MS, Cobb MH. MAP kinases and their roles in pancreatic beta-cells. Cell Biochem Biophys 2009; 40:191-200. [PMID: 15289654 DOI: 10.1385/cbb:40:3:191] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
We discuss our work examining regulation and functions of mitogen-activated protein kinases, particularly ERK1 and ERK2, in pancreatic beta-cells. These enzymes are activated by glucose, other nutrients, and insulinogenic hormones. Their activation by these agents is calcium-dependent. A number of other stimuli also activate ERK1/2, but by mechanisms distinct from those involved in nutrient sensing. Inhibition of ERK1/2 has no apparent effect on insulin secretion measured after 2 h. On the other hand, ERK1/2 activity is required for maximal glucose-dependent activation of the insulin gene promoter. The primary effort has focused on INS-1 cell lines, with supporting and confirmatory studies in intact islets and other beta-cell lines, indicating the generality of our findings in beta-cell function. Thus ERK1/2 participate in transmitting glucose-sensing information to beta-cell functions. These kinases most likely act directly and indirectly on multiple pathways that regulate beta-cell function and, in particular, to transduce an elevated glucose signal into insulin gene transcription.
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Affiliation(s)
- Shih Khoo
- Department of Pharmacology, University of Texas Southwestern Medical Center at Dallas, Dallas, TX, USA
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Saravanan R, Pari L. Effect of succinic acid monoethyl ester on hemoglobin glycation and tail tendon collagen properties in type 2 diabetic rats. Fundam Clin Pharmacol 2008; 22:291-8. [DOI: 10.1111/j.1472-8206.2008.00581.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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45
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Ni Q, Reid KR, Burant CF, Kennedy RT. Capillary LC-MS for high sensitivity metabolomic analysis of single islets of Langerhans. Anal Chem 2008; 80:3539-46. [PMID: 18399659 PMCID: PMC2597778 DOI: 10.1021/ac800406f] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Reversed-phase, packed capillary liquid chromatography interfaced by electrospray ionization to mass spectrometry was explored as an analytical method for determination of metabolites in microscale tissue samples using single islets of Langerhans as a model system. With the use of a 75 microm inner diameter column coupled to a quadrupole ion trap mass spectrometer in full scan mode, detection limits of 0.1-33 fmol were achieved for glycoloytic and tricarboxylic acid cycle metabolites. Reproducible processing of islets for analysis with little loss of metabolites was performed by rapid freezing followed by methanol-water extraction. The method yielded 20 microL of extract of which just 15 nL was injected suggesting the potential for performing multiple assays on the same islet. Approximately 200 presumed metabolites could be detected, of which 22 were identified by matching retention times and MS/MS spectra to standards. Relative standard deviations for peak detection was from 7 to 18% and was unaffected by storage for up to 11 days. The method was used to detect changes in metabolism associated with increasing extracellular islet glucose concentration from 3 to 20 mM yielding results largely consistent with known metabolism of islets. Because most previous studies of islet metabolism have only observed a few compounds at once and require far more tissue, this measurement method represents a significant advance for studies of metabolism of islets and other microscale samples.
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Affiliation(s)
- Qihui Ni
- The University of Michigan, Department of Chemistry, Ann Arbor, Michigan 48109-1055, USA
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Kowluru A. Emerging roles for protein histidine phosphorylation in cellular signal transduction: lessons from the islet beta-cell. J Cell Mol Med 2008; 12:1885-908. [PMID: 18400053 PMCID: PMC4506158 DOI: 10.1111/j.1582-4934.2008.00330.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Protein phosphorylation represents one of the key regulatory events in physiological insulin secretion from the islet β-cell. In this context, several classes of protein kinases (e.g. calcium-, cyclic nucleotide- and phospholipid-dependent protein kinases and tyrosine kinases) have been characterized in the β-cell. The majority of phosphorylated amino acids identified include phosphoserine, phosphothreonine and phosphotyrosine. Protein histidine phosphorylation has been implicated in the prokaryotic and eukaryotic cellular signal transduction. Most notably, phoshohistidine accounts for 6% of total protein phosphorylation in eukaryotes, which makes it nearly 100-fold more abundant than phosphotyrosine, but less abundant than phosphoserine and phosphothreonine. However, very little is known about the number of proteins with phosphohistidines, since they are highly labile and are rapidly lost during phosphoamino acid identification under standard experimental conditions. The overall objectives of this review are to: (i) summarize the existing evidence indicating the subcellular distribution and characterization of various histidine kinases in the islet β-cell, (ii) describe evidence for functional regulation of these kinases by agonists of insulin secretion, (iii) present a working model to implicate novel regulatory roles for histidine kinases in the receptor-independent activation, by glucose, of G-proteins endogenous to the β-cell, (iv) summarize evidence supporting the localization of protein histidine phosphatases in the islet β-cell and (v) highlight experimental evidence suggesting potential defects in the histidine kinase signalling cascade in islets derived from the Goto-Kakizaki (GK) rat, a model for type 2 diabetes. Potential avenues for future research to further decipher regulatory roles for protein histidine phosphorylation in physiological insulin secretion are also discussed.
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Affiliation(s)
- Anjaneyulu Kowluru
- Department of Pharmaceutical Sciences, Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, Detroit, MI 48201, USA.
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Uchizono Y, Alarcón C, Wicksteed BL, Marsh BJ, Rhodes CJ. The balance between proinsulin biosynthesis and insulin secretion: where can imbalance lead? Diabetes Obes Metab 2007; 9 Suppl 2:56-66. [PMID: 17919179 DOI: 10.1111/j.1463-1326.2007.00774.x] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Insulin is stored in pancreatic beta-cells in beta-granules. Whenever insulin is secreted in response to a nutrient secretagogue, there is a complementary increase in proinsulin biosynthesis to replenish intracellular insulin stores. This specific nutrient regulation of proinsulin biosynthesis is predominately regulated at the translational level. Recently, a highly conserved cis-element in the 5'-untranslated region (UTR) of preproinsulin mRNA, named ppIGE, has been identified that is required for specific translational regulation of proinsulin biosynthesis. This ppIGE is also found in the 5'-UTR of certain other translationally regulated beta-granule protein mRNAs, including the proinsulin processing endopeptidases, PC1/3 and PC2. This provides a mechanism whereby proinsulin processing is adaptable to changes in proinsulin biosynthesis. However, relatively few beta-granules undergo secretion, with most remaining in the storage pool for approximately 5 days. Aged beta-granules are retired by intracellular degradation mechanisms, either via crinophagy and/or autophagy, as another long-term means of maintaining beta-granule stores at optimal levels. When a disconnection between insulin production and secretion arises, as may occur in type 2 diabetes, autophagy further increases to maintain beta-granule numbers. However, if this increased autophagy becomes chronic, autophagia-mediated cell death occurs that could then contribute to beta-cell loss in type 2 diabetes.
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Affiliation(s)
- Y Uchizono
- Comprehensive Diabetes Center, Department of Medicine, Section of Endocrinology, Diabetes and Metabolism, The University of Chicago, Chicago, IL 60637, USA
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Pari L, Saravanan R. Beneficial effect of succinic acid monoethyl ester on erythrocyte membrane bound enzymes and antioxidant status in streptozotocin–nicotinamide induced type 2 diabetes. Chem Biol Interact 2007; 169:15-24. [PMID: 17537413 DOI: 10.1016/j.cbi.2007.04.010] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2007] [Revised: 04/19/2007] [Accepted: 04/20/2007] [Indexed: 11/17/2022]
Abstract
Succinic acid monoethyl ester (EMS) was recently proposed as an insulinotropic agent for the treatment of non-insulin dependent diabetes mellitus. In the present study the effect of EMS and metformin on erythrocyte membrane bound enzymes and antioxidants activity in plasma and erythrocytes of streptozotocin-nicotinamide induced type 2 diabeteic model was investigated. Succinic acid monoethyl ester was administered intraperitonially for 30 days to control and diabetic rats. The effect of EMS on glucose, insulin, hemoglobin, glycosylated hemoglobin, TBARS, hydroperoxide, superoxide dismutase (SOD), catalase (CAT), glutathione peroxide (Gpx), glutathione-S-transferase (GST), vitamins C and E, reduced glutathione (GSH) and membrane bound enzymes were studied. The effect of EMS was compared with metformin, a reference drug. The levels of glucose, glycosylated hemoglobin, TBARS, hyderoperoxide, and vitamin E were increased significantly whereas the level of insulin and hemoglobin, as well as antioxidants (SOD, CAT, Gpx, GST, vitamin C and GSH) membrane bound total ATPase, Na(+)/K(+)-ATPase, Ca(2+)-ATPase and Mg(2+)-ATPase were decreased significantly in streptozotocin-nicotinamide diabetic rats. Administration of EMS to diabetic rats showed a decrease in the levels of glucose, glycosylated hemoglobin, lipid peroxidation markers and vitamin E. In addition the levels of insulin, hemoglobin, enzymic antioxidants, vitamin C, and GSH and the activities of membrane bound enzymes also were increased in EMS and metformin treated diabetic rats. The present study indicates that the EMS possesses a significant beneficial effect on erythrocyte membrane bound enzymes and antioxidants defense system in addition to its antidiabetic effect.
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Affiliation(s)
- L Pari
- Department of Biochemistry and Biotechnology, Faculty of Science, Annamalai University, Annamalainagar, Tamilnadu 608002, India.
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Heart E, Yaney G, Corkey R, Schultz V, Luc E, Liu L, Deeney J, Shirihai O, Tornheim K, Smith P, Corkey B. Ca2+, NAD(P)H and membrane potential changes in pancreatic beta-cells by methyl succinate: comparison with glucose. Biochem J 2007; 403:197-205. [PMID: 17181533 PMCID: PMC1828901 DOI: 10.1042/bj20061209] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2006] [Revised: 12/14/2006] [Accepted: 12/20/2006] [Indexed: 11/17/2022]
Abstract
The present study was undertaken to determine the main metabolic secretory signals generated by the mitochondrial substrate MeS (methyl succinate) compared with glucose in mouse and rat islets and to understand the differences. Glycolysis and mitochondrial metabolism both have key roles in the stimulation of insulin secretion by glucose. Both fuels elicited comparable oscillatory patterns of Ca2+ and changes in plasma and mitochondrial membrane potential in rat islet cells and clonal pancreatic beta-cells (INS-1). Saturation of the Ca2+ signal occurred between 5 and 6 mM MeS, while secretion reached its maximum at 15 mM, suggesting operation of a K(ATP)-channel-independent pathway. Additional responses to MeS and glucose included elevated NAD(P)H autofluorescence in INS-1 cells and islets and increases in assayed NADH and NADPH and the ATP/ADP ratio. Increased NADPH and ATP/ADP ratios occurred more rapidly with MeS, although similar levels were reached after 5 min of exposure to each fuel, whereas NADH increased more with MeS than with glucose. Reversal of MeS-induced cell depolarization by Methylene Blue completely inhibited MeS-stimulated secretion, whereas basal secretion and KCl-induced changes in these parameters were not affected. MeS had no effect on secretion or signals in the mouse islets, in contrast with glucose, possibly due to a lack of malic enzyme. The data are consistent with the common intermediates being pyruvate, cytosolic NADPH or both, and suggest that cytosolic NADPH production could account for the more rapid onset of MeS-induced secretion compared with glucose stimulation.
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Affiliation(s)
- Emma Heart
- *Obesity Research Center, Evans Department of Medicine, Boston University School of Medicine, Boston, MA 02118, U.S.A
- †BioCurrents Research Center, Marine Biological Laboratory, Woods Hole, MA 02543, U.S.A
| | - Gordon C. Yaney
- *Obesity Research Center, Evans Department of Medicine, Boston University School of Medicine, Boston, MA 02118, U.S.A
| | - Richard F. Corkey
- *Obesity Research Center, Evans Department of Medicine, Boston University School of Medicine, Boston, MA 02118, U.S.A
| | - Vera Schultz
- *Obesity Research Center, Evans Department of Medicine, Boston University School of Medicine, Boston, MA 02118, U.S.A
- ‡Department of Biochemistry, Boston University School of Medicine, Boston, MA 02118, U.S.A
| | - Esthere Luc
- *Obesity Research Center, Evans Department of Medicine, Boston University School of Medicine, Boston, MA 02118, U.S.A
| | - Lihan Liu
- *Obesity Research Center, Evans Department of Medicine, Boston University School of Medicine, Boston, MA 02118, U.S.A
| | - Jude T. Deeney
- *Obesity Research Center, Evans Department of Medicine, Boston University School of Medicine, Boston, MA 02118, U.S.A
| | - Orian Shirihai
- §Department of Pharmacology and Experimental Therapeutics, Tufts University School of Medicine, Boston, MA 02118, U.S.A
| | - Keith Tornheim
- *Obesity Research Center, Evans Department of Medicine, Boston University School of Medicine, Boston, MA 02118, U.S.A
- ‡Department of Biochemistry, Boston University School of Medicine, Boston, MA 02118, U.S.A
| | - Peter J. S. Smith
- †BioCurrents Research Center, Marine Biological Laboratory, Woods Hole, MA 02543, U.S.A
| | - Barbara E. Corkey
- *Obesity Research Center, Evans Department of Medicine, Boston University School of Medicine, Boston, MA 02118, U.S.A
- ‡Department of Biochemistry, Boston University School of Medicine, Boston, MA 02118, U.S.A
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Wicksteed B, Uchizono Y, Alarcon C, McCuaig JF, Shalev A, Rhodes CJ. A cis-element in the 5' untranslated region of the preproinsulin mRNA (ppIGE) is required for glucose regulation of proinsulin translation. Cell Metab 2007; 5:221-7. [PMID: 17339029 DOI: 10.1016/j.cmet.2007.02.007] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2006] [Revised: 02/09/2007] [Accepted: 02/16/2007] [Indexed: 10/23/2022]
Abstract
Insulin production in pancreatic beta cells is predominantly regulated through glucose control of proinsulin translation. Previously, this was shown to require sequences within the untranslated regions (UTRs) of the preproinsulin (ppI) mRNA. Here, those sequences were found to be sufficient for specific glucose-regulated proinsulin translation. Furthermore, an element 40-48 bp from the 5' end of the ppI mRNA specifically bound a factor present in islets of Langerhans. Glucose-responsive factor binding to this cis-element exhibited temporal and glucose-concentration-dependent patterns that paralleled proinsulin biosynthesis. Mutating this cis-element abolished the ability of ppI mRNA UTRs to confer glucose regulation upon translation. Like the rat 5'UTR, the human ppI 5'UTR conferred glucose regulation of translation. However alternative splicing of the human 5'UTR that disrupts the cis-element abolished glucose-regulated translation. These data indicate that glucose regulation of cis-element/trans-acting factor interaction is a key component of the mechanism by which glucose regulates insulin production.
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Affiliation(s)
- Barton Wicksteed
- Comprehensive Diabetes Center, Section of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Chicago, IL 60637, USA
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