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Lavilla CJ, Billacura MP, Hanna K, Boocock DJ, Coveney C, Miles AK, Foulds GA, Murphy A, Tan A, Jackisch L, Sayers SR, Caton PW, Doig CL, McTernan PG, Colombo SL, Sale C, Turner MD. Carnosine protects stimulus-secretion coupling through prevention of protein carbonyl adduction events in cells under metabolic stress. Free Radic Biol Med 2021; 175:65-79. [PMID: 34455039 DOI: 10.1016/j.freeradbiomed.2021.08.233] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 07/23/2021] [Accepted: 08/25/2021] [Indexed: 12/17/2022]
Abstract
Type 2 diabetes is characterised by failure to control glucose homeostasis, with numerous diabetic complications attributable to the resulting exposure of cells and tissues to chronic elevated concentrations of glucose and fatty acids. This, in part, results from formation of advanced glycation and advanced lipidation end-products that are able to modify protein, lipid, or DNA structure, and disrupt normal cellular function. Herein we used mass spectrometry to identify proteins modified by two such adduction events in serum of individuals with obesity, type 2 diabetes, and gestational diabetes, along with similar analyses of human and mouse skeletal muscle cells and mouse pancreatic islets exposed to glucolipotoxic stress. We also report that carnosine, a histidine containing dipeptide, prevented 65-90% of 4-hydroxynonenal and 3-nitrotyrosine adduction events, and that this in turn preserved mitochondrial function and protected stimulus-secretion coupling in cells exposed to metabolic stress. Carnosine therefore offers significant therapeutic potential against metabolic diseases.
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Affiliation(s)
- Charlie Jr Lavilla
- Centre for Diabetes, Chronic Diseases and Ageing, School of Science and Technology, Nottingham Trent University, Clifton, Nottingham, NG11 8NS, UK
| | - Merell P Billacura
- Centre for Diabetes, Chronic Diseases and Ageing, School of Science and Technology, Nottingham Trent University, Clifton, Nottingham, NG11 8NS, UK
| | - Katie Hanna
- Centre for Diabetes, Chronic Diseases and Ageing, School of Science and Technology, Nottingham Trent University, Clifton, Nottingham, NG11 8NS, UK
| | - David J Boocock
- John van Geest Cancer Research Centre, School of Science and Technology, Nottingham Trent University, Clifton, Nottingham, NG11 8NS, UK
| | - Clare Coveney
- John van Geest Cancer Research Centre, School of Science and Technology, Nottingham Trent University, Clifton, Nottingham, NG11 8NS, UK
| | - Amanda K Miles
- John van Geest Cancer Research Centre, School of Science and Technology, Nottingham Trent University, Clifton, Nottingham, NG11 8NS, UK
| | - Gemma A Foulds
- John van Geest Cancer Research Centre, School of Science and Technology, Nottingham Trent University, Clifton, Nottingham, NG11 8NS, UK
| | - Alice Murphy
- Centre for Diabetes, Chronic Diseases and Ageing, School of Science and Technology, Nottingham Trent University, Clifton, Nottingham, NG11 8NS, UK
| | - Arnold Tan
- Centre for Diabetes, Chronic Diseases and Ageing, School of Science and Technology, Nottingham Trent University, Clifton, Nottingham, NG11 8NS, UK
| | - Laura Jackisch
- Department of Physiology, Maastricht University, 6229 ER, Maastricht, the Netherlands
| | - Sophie R Sayers
- Diabetes and Nutritional Sciences Division, King's College London, London, SE1 1UL, UK
| | - Paul W Caton
- Diabetes and Nutritional Sciences Division, King's College London, London, SE1 1UL, UK
| | - Craig L Doig
- Centre for Diabetes, Chronic Diseases and Ageing, School of Science and Technology, Nottingham Trent University, Clifton, Nottingham, NG11 8NS, UK
| | - Philip G McTernan
- Centre for Diabetes, Chronic Diseases and Ageing, School of Science and Technology, Nottingham Trent University, Clifton, Nottingham, NG11 8NS, UK
| | - Sergio L Colombo
- Centre for Diabetes, Chronic Diseases and Ageing, School of Science and Technology, Nottingham Trent University, Clifton, Nottingham, NG11 8NS, UK
| | - Craig Sale
- Sport, Health and Performance Enhancement Research Centre, School of Science and Technology, Nottingham Trent University, Clifton, Nottingham, NG11 8NS, UK
| | - Mark D Turner
- Centre for Diabetes, Chronic Diseases and Ageing, School of Science and Technology, Nottingham Trent University, Clifton, Nottingham, NG11 8NS, UK.
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Evans EA, Sayers SR, Kodji X, Xia Y, Shaikh M, Rizvi A, Frame J, Brain SD, Philpott MP, Hannen RF, Caton PW. Psoriatic skin inflammation induces a pre-diabetic phenotype via the endocrine actions of skin secretome. Mol Metab 2020; 41:101047. [PMID: 32599074 PMCID: PMC7452265 DOI: 10.1016/j.molmet.2020.101047] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 06/22/2020] [Accepted: 06/23/2020] [Indexed: 02/06/2023] Open
Abstract
OBJECTIVE Psoriasis is a chronic inflammatory skin disease that is thought to affect ∼2% of the global population. Psoriasis has been associated with ∼30% increased risk of developing type 2 diabetes (T2D), with numerous studies reporting that psoriasis is an independent risk-factor for T2D, separate from underlying obesity. Separately, studies of skin-specific transgenic mice have reported altered whole-body glucose homeostasis in these models. These studies imply a direct role for skin inflammation and dysfunction in mediating the onset of T2D in psoriasis patients, potentially via the endocrine effects of the skin secretome on key metabolic tissues. We used a combination of in vivo and ex vivo mouse models and ex vivo human imiquimod (IMQ) models to investigate the effects of psoriasis-mediated changes in the skin secretome on whole-body metabolic function. METHODS To induce psoriatic skin inflammation, mice were topically administered 75 mg of 5% IMQ cream (or Vaseline control) to a shaved dorsal region for 4 consecutive days. On day 5, mice were fasted for glucose and insulin tolerance testing, or sacrificed in the fed state with blood and tissues collected for analysis. To determine effects of the skin secretome, mouse skin was collected at day 5 from IMQ mice and cultured for 24 h. Conditioned media (CM) was collected and used 1:1 with fresh media to treat mouse explant subcutaneous adipose tissue (sAT) and isolated pancreatic islets. For human CM experiments, human skin was exposed to 5% IMQ cream for 20 min, ex vivo, to induce a psoriatic phenotype, then cultured for 24 h. CM was collected, combined 1:1 with fresh media and used to treat human sAT ex vivo. Markers of tissue inflammation and metabolic function were determined by qPCR. Beta cell function in isolated islets was measured by dynamic insulin secretion. Beta-cell proliferation was determined by measurement of Ki67 immunofluorescence histochemistry and BrDU uptake, whilst islet apoptosis was assessed by caspase 3/7 activity. All data is expressed as mean ± SEM. RESULTS Topical treatment with IMQ induced a psoriatic-like phenotype in mouse skin, evidenced by thickening, erythema and inflammation of the skin. Topical IMQ treatment induced inflammation and signs of metabolic dysfunction in sub-cutaneous and epidydimal adipose tissue, liver, skeletal muscle and gut tissue. However, consistent with islet compensation and a pre-diabetic phenotype, IMQ mice displayed improved glucose tolerance, increased insulin and c-peptide response to glucose, and increased beta cell proliferation. Treatment of sAT with psoriatic mouse or human skin-CM replicated the in vivo phenotype, leading to increased inflammation and metabolic dysfunction in mouse and human sAT. Treatment of pancreatic islets with psoriatic mouse skin-CM induced increases in beta-proliferation and apoptosis, thus partially replicating the in vivo phenotype. CONCLUSIONS Psoriasis-like skin inflammation induces a pre-diabetic phenotype, characterised by tissue inflammation and markers of metabolic dysfunction, together with islet compensation in mice. The in vivo phenotype is partially replicated by exposure of sAT and pancreatic islets to psoriatic-skin conditioned media. These results support the hypothesis that psoriatic skin inflammation, potentially via the endocrine actions of the skin secretome, may constitute a novel pathophysiological pathway mediating the development of T2D.
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Affiliation(s)
- Elizabeth A Evans
- Department of Diabetes, School of Life Course Sciences, King's College London, UK
| | - Sophie R Sayers
- Department of Diabetes, School of Life Course Sciences, King's College London, UK
| | - Xenia Kodji
- Section of Vascular Biology & Inflammation, School of Cardiovascular Medicine & Sciences, BHF Centre for Cardiovascular Sciences, King's College London, London, UK; A∗STAR - Agency for Science, Technology and Research - SRIS, Singapore
| | - Yue Xia
- Department of Diabetes, School of Life Course Sciences, King's College London, UK
| | - Mahum Shaikh
- Department of Diabetes, School of Life Course Sciences, King's College London, UK
| | - Alizah Rizvi
- Department of Diabetes, School of Life Course Sciences, King's College London, UK
| | - James Frame
- Anglia-Ruskin University, Chelmsford, Essex, UK; Springfield Hospital, Chelmsford, UK
| | - Susan D Brain
- Section of Vascular Biology & Inflammation, School of Cardiovascular Medicine & Sciences, BHF Centre for Cardiovascular Sciences, King's College London, London, UK
| | - Michael P Philpott
- Centre for Cell Biology and Cutaneous Research, Blizard Institute, Queen Mary University of London, London, UK
| | - Rosalind F Hannen
- Centre for Cell Biology and Cutaneous Research, Blizard Institute, Queen Mary University of London, London, UK
| | - Paul W Caton
- Department of Diabetes, School of Life Course Sciences, King's College London, UK.
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Sayers SR, Beavil RL, Fine NHF, Huang GC, Choudhary P, Pacholarz KJ, Barran PE, Butterworth S, Mills CE, Cruickshank JK, Silvestre MP, Poppitt SD, McGill AT, Lavery GG, Hodson DJ, Caton PW. Structure-functional changes in eNAMPT at high concentrations mediate mouse and human beta cell dysfunction in type 2 diabetes. Diabetologia 2020; 63:313-323. [PMID: 31732790 PMCID: PMC6946736 DOI: 10.1007/s00125-019-05029-y] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Accepted: 09/11/2019] [Indexed: 02/26/2023]
Abstract
AIMS/HYPOTHESIS Progressive decline in functional beta cell mass is central to the development of type 2 diabetes. Elevated serum levels of extracellular nicotinamide phosphoribosyltransferase (eNAMPT) are associated with beta cell failure in type 2 diabetes and eNAMPT immuno-neutralisation improves glucose tolerance in mouse models of diabetes. Despite this, the effects of eNAMPT on functional beta cell mass are poorly elucidated, with some studies having separately reported beta cell-protective effects of eNAMPT. eNAMPT exists in structurally and functionally distinct monomeric and dimeric forms. Dimerisation is essential for the NAD-biosynthetic capacity of NAMPT. Monomeric eNAMPT does not possess NAD-biosynthetic capacity and may exert distinct NAD-independent effects. This study aimed to fully characterise the structure-functional effects of eNAMPT on pancreatic beta cell functional mass and to relate these to beta cell failure in type 2 diabetes. METHODS CD-1 mice and serum from obese humans who were without diabetes, with impaired fasting glucose (IFG) or with type 2 diabetes (from the Body Fat, Surgery and Hormone [BodyFatS&H] study) or with or at risk of developing type 2 diabetes (from the VaSera trial) were used in this study. We generated recombinant wild-type and monomeric eNAMPT to explore the effects of eNAMPT on functional beta cell mass in isolated mouse and human islets. Beta cell function was determined by static and dynamic insulin secretion and intracellular calcium microfluorimetry. NAD-biosynthetic capacity of eNAMPT was assessed by colorimetric and fluorescent assays and by native mass spectrometry. Islet cell number was determined by immunohistochemical staining for insulin, glucagon and somatostatin, with islet apoptosis determined by caspase 3/7 activity. Markers of inflammation and beta cell identity were determined by quantitative reverse transcription PCR. Total, monomeric and dimeric eNAMPT and nicotinamide mononucleotide (NMN) were evaluated by ELISA, western blot and fluorometric assay using serum from non-diabetic, glucose intolerant and type 2 diabetic individuals. RESULTS eNAMPT exerts bimodal and concentration- and structure-functional-dependent effects on beta cell functional mass. At low physiological concentrations (~1 ng/ml), as seen in serum from humans without diabetes, eNAMPT enhances beta cell function through NAD-dependent mechanisms, consistent with eNAMPT being present as a dimer. However, as eNAMPT concentrations rise to ~5 ng/ml, as in type 2 diabetes, eNAMPT begins to adopt a monomeric form and mediates beta cell dysfunction, reduced beta cell identity and number, increased alpha cell number and increased apoptosis, through NAD-independent proinflammatory mechanisms. CONCLUSIONS/INTERPRETATION We have characterised a novel mechanism of beta cell dysfunction in type 2 diabetes. At low physiological levels, eNAMPT exists in dimer form and maintains beta cell function and identity through NAD-dependent mechanisms. However, as eNAMPT levels rise, as in type 2 diabetes, structure-functional changes occur resulting in marked elevation of monomeric eNAMPT, which induces a diabetic phenotype in pancreatic islets. Strategies to selectively target monomeric eNAMPT could represent promising therapeutic strategies for the treatment of type 2 diabetes.
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Affiliation(s)
- Sophie R Sayers
- Diabetes Research Group, Department of Diabetes, School of Life Course Sciences, King's College London, Hodgkin Building, Guy's Campus, London, SE1 1UL, UK
| | - Rebecca L Beavil
- Protein Production Facility, Randall Centre for Cell and Molecular Biophysics, King's College London, London, UK
| | - Nicholas H F Fine
- Institute of Metabolism and Systems Research (IMSR), University of Birmingham, Birmingham, UK
- Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham, Birmingham, UK
- Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham, UK
| | - Guo C Huang
- Diabetes Research Group, Department of Diabetes, School of Life Course Sciences, King's College London, Hodgkin Building, Guy's Campus, London, SE1 1UL, UK
| | - Pratik Choudhary
- Diabetes Research Group, Department of Diabetes, School of Life Course Sciences, King's College London, Hodgkin Building, Guy's Campus, London, SE1 1UL, UK
| | - Kamila J Pacholarz
- Michael Barber Centre for Collaborative Mass Spectrometry, School of Chemistry, Manchester Institute of Biotechnology, Manchester, UK
| | - Perdita E Barran
- Michael Barber Centre for Collaborative Mass Spectrometry, School of Chemistry, Manchester Institute of Biotechnology, Manchester, UK
| | - Sam Butterworth
- Division of Pharmacy and Optometry, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Charlotte E Mills
- Department of Nutritional Sciences, School of Life Course Sciences, King's College London, London, UK
- Nutrition Research Group, University of Reading, Reading, UK
| | - J Kennedy Cruickshank
- Department of Nutritional Sciences, School of Life Course Sciences, King's College London, London, UK
| | - Marta P Silvestre
- Human Nutrition Unit, School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - Sally D Poppitt
- Human Nutrition Unit, School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - Anne-Thea McGill
- Human Nutrition Unit, School of Biological Sciences, University of Auckland, Auckland, New Zealand
- School of Health & Human Sciences, Southern Cross University, Lismore, NSW, Australia
| | - Gareth G Lavery
- Institute of Metabolism and Systems Research (IMSR), University of Birmingham, Birmingham, UK
- Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham, Birmingham, UK
- Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham, UK
| | - David J Hodson
- Institute of Metabolism and Systems Research (IMSR), University of Birmingham, Birmingham, UK
- Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham, Birmingham, UK
- Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham, UK
| | - Paul W Caton
- Diabetes Research Group, Department of Diabetes, School of Life Course Sciences, King's College London, Hodgkin Building, Guy's Campus, London, SE1 1UL, UK.
- Department of Nutritional Sciences, School of Life Course Sciences, King's College London, London, UK.
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4
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Cripps MJ, Bagnati M, Jones TA, Ogunkolade BW, Sayers SR, Caton PW, Hanna K, Billacura MP, Fair K, Nelson C, Lowe R, Hitman GA, Berry MD, Turner MD. Identification of a subset of trace amine-associated receptors and ligands as potential modulators of insulin secretion. Biochem Pharmacol 2020; 171:113685. [DOI: 10.1016/j.bcp.2019.113685] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Accepted: 10/24/2019] [Indexed: 12/19/2022]
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Kieswich J, Sayers SR, Silvestre MF, Harwood SM, Yaqoob MM, Caton PW. Monomeric eNAMPT in the development of experimental diabetes in mice: a potential target for type 2 diabetes treatment. Diabetologia 2016; 59:2477-2486. [PMID: 27541013 PMCID: PMC5506101 DOI: 10.1007/s00125-016-4076-3] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Accepted: 07/22/2016] [Indexed: 01/18/2023]
Abstract
AIMS/HYPOTHESIS Serum extracellular nicotinamide phosphoribosyltransferase (eNAMPT) concentrations are elevated in type 2 diabetes. However, the relationship between abnormally elevated serum eNAMPT and type 2 diabetes pathophysiology is unclear. eNAMPT circulates in functionally and structurally distinct monomeric and dimeric forms. Dimeric eNAMPT promotes NAD biosynthesis. The role of eNAMPT-monomer is unclear but it may have NAD-independent proinflammatory effects. However, studies of eNAMPT in type 2 diabetes have not distinguished between monomeric and dimeric forms. Since type 2 diabetes is characterised by chronic inflammation, we hypothesised a selective NAD-independent role for eNAMPT-monomer in type 2 diabetes. METHODS Two mouse models were used to examine the role of eNAMPT-monomer in type 2 diabetes; (1) a mouse model of diabetes fed a high-fat diet (HFD) for 10 weeks received i.p. injections with an anti-monomeric-eNAMPT antibody; and (2) lean non-diabetic mice received i.p. injections with recombinant monomeric eNAMPT daily for 14 days. RESULTS Serum monomeric eNAMPT levels were elevated in HFD-fed mouse models of diabetes, whilst eNAMPT-dimer levels were unchanged. eNAMPT-monomer neutralisation in HFD-fed mice resulted in lower blood glucose levels, amelioration of impaired glucose tolerance (IGT) and whole-body insulin resistance, improved pancreatic islet function, and reduced inflammation. These effects were maintained for at least 3 weeks post-treatment. eNAMPT-monomer administration induced a diabetic phenotype in mice, characterised by elevated blood glucose, IGT, impaired pancreatic insulin secretion and the presence of systemic and tissue inflammation, without changes in NAD levels. CONCLUSIONS/INTERPRETATION We demonstrate that elevation of monomeric-eNAMPT plays an important role in the pathogenesis of diet-induced diabetes via proinflammatory mechanisms. These data provide proof-of-concept evidence that the eNAMPT-monomer represents a potential therapeutic target for type 2 diabetes.
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Affiliation(s)
- Julius Kieswich
- Translational Medicine and Therapeutics, William Harvey Research Institute, Bart's and the London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Sophie R Sayers
- Diabetes Research Group, Division of Diabetes and Nutritional Sciences, King's College London, Hodgkin Building, Guy's Campus, London, SE1 1UL, UK
| | - Marta F Silvestre
- Faculdade de Medicina da Universidade de Lisboa, Lisbon, Portugal
- Human Nutrition Unit, University of Auckland, Auckland, New Zealand
| | - Steven M Harwood
- Translational Medicine and Therapeutics, William Harvey Research Institute, Bart's and the London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Muhammad M Yaqoob
- Translational Medicine and Therapeutics, William Harvey Research Institute, Bart's and the London School of Medicine and Dentistry, Queen Mary University of London, London, UK
| | - Paul W Caton
- Diabetes Research Group, Division of Diabetes and Nutritional Sciences, King's College London, Hodgkin Building, Guy's Campus, London, SE1 1UL, UK.
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Martinez-Sanchez A, Pullen TJ, Chabosseau P, Zhang Q, Haythorne E, Cane MC, Nguyen-Tu MS, Sayers SR, Rutter GA. Disallowance of Acot7 in β-Cells Is Required for Normal Glucose Tolerance and Insulin Secretion. Diabetes 2016; 65:1268-82. [PMID: 26861785 PMCID: PMC6101210 DOI: 10.2337/db15-1240] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Accepted: 02/04/2016] [Indexed: 12/18/2022]
Abstract
Encoding acyl-CoA thioesterase-7 (Acot7) is one of ∼60 genes expressed ubiquitously across tissues but relatively silenced, or disallowed, in pancreatic β-cells. The capacity of ACOT7 to hydrolyze long-chain acyl-CoA esters suggests potential roles in β-oxidation, lipid biosynthesis, signal transduction, or insulin exocytosis. We explored the physiological relevance of β-cell-specific Acot7 silencing by re-expressing ACOT7 in these cells. ACOT7 overexpression in clonal MIN6 and INS1(832/13) β-cells impaired insulin secretion in response to glucose plus fatty acids. Furthermore, in a panel of transgenic mouse lines, we demonstrate that overexpression of mitochondrial ACOT7 selectively in the adult β-cell reduces glucose tolerance dose dependently and impairs glucose-stimulated insulin secretion. By contrast, depolarization-induced secretion was unaffected, arguing against a direct action on the exocytotic machinery. Acyl-CoA levels, ATP/ADP increases, membrane depolarization, and Ca(2+) fluxes were all markedly reduced in transgenic mouse islets, whereas glucose-induced oxygen consumption was unchanged. Although glucose-induced increases in ATP/ADP ratio were similarly lowered after ACOT7 overexpression in INS1(832/13) cells, changes in mitochondrial membrane potential were unaffected, consistent with an action of Acot7 to increase cellular ATP consumption. Because Acot7 mRNA levels are increased in human islets in type 2 diabetes, inhibition of the enzyme might provide a novel therapeutic strategy.
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Affiliation(s)
- Aida Martinez-Sanchez
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Imperial Centre for Translational and Experimental Medicine, Imperial College London, London, U.K
| | - Timothy J Pullen
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Imperial Centre for Translational and Experimental Medicine, Imperial College London, London, U.K
| | - Pauline Chabosseau
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Imperial Centre for Translational and Experimental Medicine, Imperial College London, London, U.K
| | | | - Elizabeth Haythorne
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Imperial Centre for Translational and Experimental Medicine, Imperial College London, London, U.K
| | - Matthew C Cane
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Imperial Centre for Translational and Experimental Medicine, Imperial College London, London, U.K
| | - Marie-Sophie Nguyen-Tu
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Imperial Centre for Translational and Experimental Medicine, Imperial College London, London, U.K
| | - Sophie R Sayers
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Imperial Centre for Translational and Experimental Medicine, Imperial College London, London, U.K
| | - Guy A Rutter
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Imperial Centre for Translational and Experimental Medicine, Imperial College London, London, U.K.
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Sayers SR, Reimann F, Gribble FM, Parker H, Zac-Varghese S, Bloom SR, Foretz M, Viollet B, Rutter GA. Proglucagon Promoter Cre-Mediated AMPK Deletion in Mice Increases Circulating GLP-1 Levels and Oral Glucose Tolerance. PLoS One 2016; 11:e0149549. [PMID: 27010458 PMCID: PMC4806996 DOI: 10.1371/journal.pone.0149549] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Accepted: 02/02/2016] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND Enteroendocrine L-cells synthesise and release the gut hormone glucagon-like peptide-1 (GLP-1) in response to food transit. Deletion of the tumour suppressor kinase LKB1 from proglucagon-expressing cells leads to the generation of intestinal polyps but no change in circulating GLP-1 levels. Here, we explore the role of the downstream kinase AMP-activated protein kinase (AMPK) in these cells. METHOD Loss of AMPK from proglucagon-expressing cells was achieved using a preproglucagon promoter-driven Cre (iGluCre) to catalyse recombination of floxed alleles of AMPKα1 and α2. Oral and intraperitoneal glucose tolerance were measured using standard protocols. L-cell mass was measured by immunocytochemistry. Hormone and peptide levels were measured by electrochemical-based luminescence detection or radioimmunoassay. RESULTS Recombination with iGluCre led to efficient deletion of AMPK from intestinal L- and pancreatic alpha-cells. In contrast to mice rendered null for LKB1 using the same strategy, mice deleted for AMPK displayed an increase (WT: 0.05 ± 0.01, KO: 0.09±0.02%, p<0.01) in L-cell mass and elevated plasma fasting (WT: 5.62 ± 0.800 pg/ml, KO: 14.5 ± 1.870, p<0.01) and fed (WT: 15.7 ± 1.48pg/ml, KO: 22.0 ± 6.62, p<0.01) GLP-1 levels. Oral, but not intraperitoneal, glucose tolerance was significantly improved by AMPK deletion, whilst insulin and glucagon levels were unchanged despite an increase in alpha to beta cell ratio (WT: 0.23 ± 0.02, KO: 0.33 ± 0.03, p<0.01). CONCLUSION AMPK restricts L-cell growth and GLP-1 secretion to suppress glucose tolerance. Targeted inhibition of AMPK in L-cells may thus provide a new therapeutic strategy in some forms of type 2 diabetes.
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Affiliation(s)
- Sophie R. Sayers
- Department of Cell Biology and Functional Genomics, Imperial College London, London, W12 ONN, United Kingdom
| | - Frank Reimann
- Wellcome Trust - MRC Institute of Metabolic Science, University of Cambridge, Hills Road, Cambridge, CB2 0QQ, United Kingdom
| | - Fiona M. Gribble
- Wellcome Trust - MRC Institute of Metabolic Science, University of Cambridge, Hills Road, Cambridge, CB2 0QQ, United Kingdom
| | - Helen Parker
- Wellcome Trust - MRC Institute of Metabolic Science, University of Cambridge, Hills Road, Cambridge, CB2 0QQ, United Kingdom
| | - Sagen Zac-Varghese
- Department of Investigative Medicine, Imperial College London, London, W12 ONN, United Kingdom
| | - Stephen R. Bloom
- Department of Investigative Medicine, Imperial College London, London, W12 ONN, United Kingdom
| | - Marc Foretz
- INSERM, U1016, Institut Cochin, 75014 Paris, France
- CNRS, UMR8104, 75014 Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, 75014 Paris, France
| | - Benoit Viollet
- INSERM, U1016, Institut Cochin, 75014 Paris, France
- CNRS, UMR8104, 75014 Paris, France
- Université Paris Descartes, Sorbonne Paris Cité, 75014 Paris, France
| | - Guy A. Rutter
- Department of Cell Biology and Functional Genomics, Imperial College London, London, W12 ONN, United Kingdom
- * E-mail:
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