1
|
Cheung R, Pizza G, Chabosseau P, Rolando D, Tomas A, Burgoyne T, Wu Z, Salowka A, Thapa A, Macklin A, Cao Y, Nguyen-Tu MS, Dickerson MT, Jacobson DA, Marchetti P, Shapiro J, Piemonti L, de Koning E, Leclerc I, Bouzakri K, Sakamoto K, Smith DM, Rutter GA, Martinez-Sanchez A. Glucose-Dependent miR-125b Is a Negative Regulator of β-Cell Function. Diabetes 2022; 71:1525-1545. [PMID: 35476777 PMCID: PMC9998846 DOI: 10.2337/db21-0803] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [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: 09/04/2021] [Accepted: 04/11/2022] [Indexed: 11/13/2022]
Abstract
Impaired pancreatic β-cell function and insulin secretion are hallmarks of type 2 diabetes. miRNAs are short, noncoding RNAs that silence gene expression vital for the development and function of β cells. We have previously shown that β cell-specific deletion of the important energy sensor AMP-activated protein kinase (AMPK) results in increased miR-125b-5p levels. Nevertheless, the function of this miRNA in β cells is unclear. We hypothesized that miR-125b-5p expression is regulated by glucose and that this miRNA mediates some of the deleterious effects of hyperglycemia in β cells. Here, we show that islet miR-125b-5p expression is upregulated by glucose in an AMPK-dependent manner and that short-term miR-125b-5p overexpression impairs glucose-stimulated insulin secretion (GSIS) in the mouse insulinoma MIN6 cells and in human islets. An unbiased, high-throughput screen in MIN6 cells identified multiple miR-125b-5p targets, including the transporter of lysosomal hydrolases M6pr and the mitochondrial fission regulator Mtfp1. Inactivation of miR-125b-5p in the human β-cell line EndoCβ-H1 shortened mitochondria and enhanced GSIS, whereas mice overexpressing miR-125b-5p selectively in β cells (MIR125B-Tg) were hyperglycemic and glucose intolerant. MIR125B-Tg β cells contained enlarged lysosomal structures and had reduced insulin content and secretion. Collectively, we identify miR-125b as a glucose-controlled regulator of organelle dynamics that modulates insulin secretion.
Collapse
Affiliation(s)
- Rebecca Cheung
- Section of Cell Biology and Functional Genomics, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, U.K
| | - Grazia Pizza
- Section of Cell Biology and Functional Genomics, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, U.K
| | - Pauline Chabosseau
- Section of Cell Biology and Functional Genomics, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, U.K
| | - Delphine Rolando
- Beta Cell Genome Regulation Laboratory, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, U.K
| | - Alejandra Tomas
- Section of Cell Biology and Functional Genomics, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, U.K
| | - Thomas Burgoyne
- UCL Institute of Ophthalmology, University College London, London, U.K
| | - Zhiyi Wu
- Section of Cell Biology and Functional Genomics, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, U.K
| | - Anna Salowka
- Section of Cell Biology and Functional Genomics, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, U.K
| | - Anusha Thapa
- Section of Cell Biology and Functional Genomics, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, U.K
| | - Annabel Macklin
- Section of Cell Biology and Functional Genomics, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, U.K
| | - Yufei Cao
- Section of Cell Biology and Functional Genomics, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, U.K
| | - Marie-Sophie Nguyen-Tu
- Section of Cell Biology and Functional Genomics, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, U.K
| | - Matthew T. Dickerson
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN
| | - David A. Jacobson
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN
| | - Piero Marchetti
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - James Shapiro
- Clinical Islet Laboratory and Clinical Islet Transplant Program, University of Alberta, Edmonton, Canada
| | | | - Eelco de Koning
- Department of Medicine, Leiden University Medical Center, Leiden, the Netherlands
| | | | - Karim Bouzakri
- UMR DIATHEC, EA 7294, Centre Européen d'Etude du Diabète, Université de Strasbourg, Fédération de Médecine Translationnelle de Strasbourg, Strasbourg, France
| | - Kei Sakamoto
- Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark
| | - David M. Smith
- Emerging Innovations Unit, Discovery Sciences, R&D, AstraZeneca, Cambridge, U.K
| | - Guy A. Rutter
- Section of Cell Biology and Functional Genomics, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, U.K
- CR-CHUM, University of Montreal, Montreal, Quebec, Canada
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore
| | - Aida Martinez-Sanchez
- Section of Cell Biology and Functional Genomics, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, U.K
- Corresponding author: Aida Martinez-Sanchez,
| |
Collapse
|
2
|
Nguyen-Tu MS, Harris J, Martinez-Sanchez A, Chabosseau P, Hu M, Georgiadou E, Pollard A, Otero P, Lopez-Noriega L, Leclerc I, Sakamoto K, Schmoll D, Smith DM, Carling D, Rutter GA. Opposing effects on regulated insulin secretion of acute vs chronic stimulation of AMP-activated protein kinase. Diabetologia 2022; 65:997-1011. [PMID: 35294578 PMCID: PMC9076735 DOI: 10.1007/s00125-022-05673-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 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: 06/28/2021] [Accepted: 12/13/2021] [Indexed: 11/26/2022]
Abstract
AIMS/HYPOTHESIS Although targeted in extrapancreatic tissues by several drugs used to treat type 2 diabetes, the role of AMP-activated protein kinase (AMPK) in the control of insulin secretion is still debatable. Previous studies have used pharmacological activators of limited selectivity and specificity, and none has examined in primary pancreatic beta cells the actions of the latest generation of highly potent and specific activators that act via the allosteric drug and metabolite (ADaM) site. METHODS AMPK was activated acutely in islets isolated from C57BL6/J mice, and in an EndoC-βH3 cell line, using three structurally distinct ADaM site activators (991, PF-06409577 and RA089), with varying selectivity for β1- vs β2-containing complexes. Mouse lines expressing a gain-of-function mutation in the γ1 AMPK subunit (D316a) were generated to examine the effects of chronic AMPK stimulation in the whole body, or selectively in the beta cell. RESULTS Acute (1.5 h) treatment of wild-type mouse islets with 991, PF-06409577 or RA089 robustly stimulated insulin secretion at high glucose concentrations (p<0.01, p<0.05 and p<0.001, respectively), despite a lowering of glucose-induced intracellular free Ca2+ dynamics in response to 991 (AUC, p<0.05) and to RA089 at the highest dose (25 μmol/l) at 5.59 min (p<0.05). Although abolished in the absence of AMPK, the effects of 991 were observed in the absence of the upstream kinase, liver kinase B1, further implicating 'amplifying' pathways. In marked contrast, chronic activation of AMPK, either globally or selectively in the beta cell, achieved using a gain-of-function mutant, impaired insulin release in vivo (p<0.05 at 15 min following i.p. injection of 3 mmol/l glucose) and in vitro (p<0.01 following incubation of islets with 17 mmol/l glucose), and lowered glucose tolerance (p<0.001). CONCLUSIONS/INTERPRETATION AMPK activation exerts complex, time-dependent effects on insulin secretion. These observations should inform the design and future clinical use of AMPK modulators.
Collapse
Affiliation(s)
- Marie-Sophie Nguyen-Tu
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
| | - Joseph Harris
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
| | - Aida Martinez-Sanchez
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
| | - Pauline Chabosseau
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
| | - Ming Hu
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
| | - Eleni Georgiadou
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
| | - Alice Pollard
- MRC- London Institute of Medical Sciences, Imperial College London, London, UK
- Structure Biophysics and Fragments, Discovery Sciences, AstraZeneca R&D, Cambridge, UK
| | - Pablo Otero
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
| | - Livia Lopez-Noriega
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
| | - Isabelle Leclerc
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
| | - Kei Sakamoto
- Novo Nordisk Center for Basic Metabolic Research, Copenhagen, Denmark
| | - Dieter Schmoll
- Sanofi-Aventis Deutschland GmbH, Frankfurt am Main, Germany
| | - David M Smith
- Emerging Innovations Unit, Discovery Sciences, AstraZeneca R&D , Cambridge, UK
| | - David Carling
- MRC- London Institute of Medical Sciences, Imperial College London, London, UK
| | - Guy A Rutter
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK.
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Republic of Singapore.
- CR-CHUM, University of Montréal, Montréal, QC, Canada.
| |
Collapse
|
3
|
Nguyen-Tu MS, Martinez-Sanchez A, Leclerc I, Rutter GA, da Silva Xavier G. Adipocyte-specific deletion of Tcf7l2 induces dysregulated lipid metabolism and impairs glucose tolerance in mice. Diabetologia 2021; 64:129-141. [PMID: 33068125 PMCID: PMC7567653 DOI: 10.1007/s00125-020-05292-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [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: 06/17/2020] [Accepted: 08/07/2020] [Indexed: 12/11/2022]
Abstract
AIMS/HYPOTHESIS Transcription factor 7-like 2 (TCF7L2) is a downstream effector of the Wnt/β-catenin signalling pathway implicated in type 2 diabetes risk through genome-wide association studies. Although its expression is critical for adipocyte development, the potential roles of changes in adipose tissue TCF7L2 levels in diabetes risk are poorly defined. Here, we investigated whether forced changes in Tcf7l2 expression in adipocytes affect whole body glucose or lipid metabolism and crosstalk between disease-relevant tissues. METHODS Tcf7l2 was selectively ablated in mature adipocytes in C57BL/6J mice using Cre recombinase under Adipoq promoter control to recombine Tcf7l2 alleles floxed at exon 1 (referred to as aTCF7L2 mice). aTCF7L2 mice were fed normal chow or a high-fat diet for 12 weeks. Glucose and insulin sensitivity, as well as beta cell function, were assessed in vivo and in vitro. Levels of circulating NEFA, selected hormones and adipokines were measured using standard assays. RESULTS Reduced TCF7L2 expression in adipocytes altered glucose tolerance and insulin secretion in male but not in female mice. Thus, on a normal chow diet, male heterozygote knockout mice (aTCF7L2het) exhibited impaired glucose tolerance at 16 weeks (p = 0.03) and increased fat mass (1.4 ± 0.1-fold, p = 0.007) but no changes in insulin secretion. In contrast, male homozygote knockout (aTCF7L2hom) mice displayed normal body weight but impaired oral glucose tolerance at 16 weeks (p = 0.0001). These changes were mechanistically associated with impaired in vitro glucose-stimulated insulin secretion (decreased 0.5 ± 0.1-fold vs control mice, p = 0.02) and decreased levels of the incretins glucagon-like peptide-1 and glucose-dependent insulinotropic polypeptide (0.6 ± 0.1-fold and 0.4 ± 0.1-fold vs control mice, p = 0.04 and p < 0.0001, respectively). Circulating levels of plasma NEFA and fatty acid binding protein 4 were increased by 1.3 ± 0.1-fold and 1.8 ± 0.3-fold vs control mice (p = 0.03 and p = 0.05, respectively). Following exposure to a high-fat diet for 12 weeks, male aTCF7L2hom mice exhibited reduced in vivo glucose-stimulated insulin secretion (0.5 ± 0.1-fold vs control mice, p = 0.02). CONCLUSIONS/INTERPRETATION Loss of Tcf7l2 gene expression selectively in adipocytes leads to a sexually dimorphic phenotype, with impairments not only in adipocytes, but also in pancreatic islet and enteroendocrine cells in male mice only. Our findings suggest novel roles for adipokines and incretins in the effects of diabetes-associated variants in TCF7L2, and further illuminate the roles of TCF7L2 in glucose homeostasis and diabetes risk. Graphical abstract.
Collapse
Affiliation(s)
- Marie-Sophie Nguyen-Tu
- Section of Cell Biology and Functional Genomics, Department of Metabolism, Digestion and Reproduction, Hammersmith Hospital, Imperial College Centre for Translational and Experimental Medicine, London, UK
| | - Aida Martinez-Sanchez
- Section of Cell Biology and Functional Genomics, Department of Metabolism, Digestion and Reproduction, Hammersmith Hospital, Imperial College Centre for Translational and Experimental Medicine, London, UK
| | - Isabelle Leclerc
- Section of Cell Biology and Functional Genomics, Department of Metabolism, Digestion and Reproduction, Hammersmith Hospital, Imperial College Centre for Translational and Experimental Medicine, London, UK
| | - Guy A Rutter
- Section of Cell Biology and Functional Genomics, Department of Metabolism, Digestion and Reproduction, Hammersmith Hospital, Imperial College Centre for Translational and Experimental Medicine, London, UK.
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore.
| | - Gabriela da Silva Xavier
- Section of Cell Biology and Functional Genomics, Department of Metabolism, Digestion and Reproduction, Hammersmith Hospital, Imperial College Centre for Translational and Experimental Medicine, London, UK.
- Institute of Metabolism and Systems Research, University of Birmingham, Birmingham, UK.
| |
Collapse
|
4
|
Ma Y, Ratnasabapathy R, De Backer I, Izzi-Engbeaya C, Nguyen-Tu MS, Cuenco J, Jones B, John CD, Lam BY, Rutter GA, Yeo GS, Dhillo WS, Gardiner J. Glucose in the hypothalamic paraventricular nucleus regulates GLP-1 release. JCI Insight 2020; 5:132760. [PMID: 32229720 PMCID: PMC7205434 DOI: 10.1172/jci.insight.132760] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Accepted: 03/25/2020] [Indexed: 01/23/2023] Open
Abstract
Glucokinase (GK) is highly expressed in the hypothalamic paraventricular nucleus (PVN); however, its role is currently unknown. We found that GK in the PVN acts as part of a glucose-sensing mechanism within the PVN that regulates glucose homeostasis by controlling glucagon-like peptide 1 (GLP-1) release. GLP-1 is released from enteroendocrine L cells in response to oral glucose. Here we identify a brain mechanism critical to the release of GLP-1 in response to oral glucose. We show that increasing expression of GK or injection of glucose into the PVN increases GLP-1 release in response to oral glucose. On the contrary, decreasing expression of GK or injection of nonmetabolizable glucose into the PVN prevents GLP-1 release. Our results demonstrate that gluco-sensitive GK neurons in the PVN are critical to the response to oral glucose and subsequent release of GLP-1.
Collapse
Affiliation(s)
- Yue Ma
- Section of Endocrinology and Investigative Medicine and
| | | | | | | | - Marie-Sophie Nguyen-Tu
- Section of Cell Biology and Functional Genomics, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, United Kingdom
| | | | - Ben Jones
- Section of Endocrinology and Investigative Medicine and
| | | | - Brian Yh Lam
- University of Cambridge Metabolic Research Laboratories and MRC Metabolic Diseases Unit, Wellcome Trust-MRC Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge, United Kingdom
| | - Guy A Rutter
- Section of Cell Biology and Functional Genomics, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, United Kingdom
| | - Giles Sh Yeo
- University of Cambridge Metabolic Research Laboratories and MRC Metabolic Diseases Unit, Wellcome Trust-MRC Institute of Metabolic Science, Addenbrooke's Hospital, Cambridge, United Kingdom
| | | | | |
Collapse
|
5
|
Nguyen-Tu MS, da Silva Xavier G, Leclerc I, Rutter GA. Correction: Transcription factor-7-like 2 ( TCF7L2) gene acts downstream of the Lkb1/Stk11 kinase to control mTOR signaling, β cell growth, and insulin secretion. J Biol Chem 2018; 293:18420. [PMID: 30470729 DOI: 10.1074/jbc.aac118.006541] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
|
6
|
Ratnasabapathy R, Ma Y, Izzi-Engbeaya C, Nguyen-Tu MS, Richardson E, Hussain S, De BI, Holton C, Norton M, Carrat G, Schwappach B, Rutter GA, Dhillo WS, Gardiner JV. Hypothalamic arcuate glucokinase and its downstream pathways are critical in glucose homeostasis. ACTA ACUST UNITED AC 2018. [DOI: 10.1530/endoabs.59.oc3.5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
|
7
|
Ma Y, Ratnasabapathy R, Izzi-Engbeaya C, Nguyen-Tu MS, Richardson E, Hussain S, De Backer I, Holton C, Norton M, Carrat G, Schwappach B, Rutter GA, Dhillo WS, Gardiner J. Hypothalamic arcuate nucleus glucokinase regulates insulin secretion and glucose homeostasis. Diabetes Obes Metab 2018; 20:2246-2254. [PMID: 29748994 PMCID: PMC6099255 DOI: 10.1111/dom.13359] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [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: 12/13/2017] [Revised: 04/30/2018] [Accepted: 05/09/2018] [Indexed: 01/08/2023]
Abstract
AIMS To investigate the role of arcuate glucokinase (GK) in the regulation of glucose homeostasis. MATERIALS AND METHODS A recombinant adeno-associated virus expressing either GK or an antisense GK construct was used to alter GK activity specifically in the hypothalamic arcuate nucleus (arc). GK activity in this nucleus was also increased by stereotactic injection of the GK activator, compound A. The effect of altered arc GK activity on glucose homeostasis was subsequently investigated using glucose and insulin tolerance tests. RESULTS Increased GK activity specifically within the arc increased insulin secretion and improved glucose tolerance in rats during oral glucose tolerance tests. Decreased GK activity in this nucleus reduced insulin secretion and increased glucose levels during the same tests. Insulin sensitivity was not affected in either case. The effect of arc GK was maintained in a model of type 2 diabetes. CONCLUSIONS These results demonstrate a role for arc GK in systemic glucose homeostasis.
Collapse
Affiliation(s)
- Yue Ma
- Section of Endocrinology and Investigative Medicine, Division of Diabetes, Endocrinology and Metabolism, Imperial College London, London, UK
| | - Risheka Ratnasabapathy
- Section of Endocrinology and Investigative Medicine, Division of Diabetes, Endocrinology and Metabolism, Imperial College London, London, UK
| | - Chioma Izzi-Engbeaya
- Section of Endocrinology and Investigative Medicine, Division of Diabetes, Endocrinology and Metabolism, Imperial College London, London, UK
| | - Marie-Sophie Nguyen-Tu
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Imperial College London, London, UK
| | - Errol Richardson
- Section of Endocrinology and Investigative Medicine, Division of Diabetes, Endocrinology and Metabolism, Imperial College London, London, UK
| | - Sufyan Hussain
- Section of Endocrinology and Investigative Medicine, Division of Diabetes, Endocrinology and Metabolism, Imperial College London, London, UK
| | - Ivan De Backer
- Section of Endocrinology and Investigative Medicine, Division of Diabetes, Endocrinology and Metabolism, Imperial College London, London, UK
| | - Christopher Holton
- Section of Endocrinology and Investigative Medicine, Division of Diabetes, Endocrinology and Metabolism, Imperial College London, London, UK
| | - Mariana Norton
- Section of Endocrinology and Investigative Medicine, Division of Diabetes, Endocrinology and Metabolism, Imperial College London, London, UK
| | - Gaelle Carrat
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Imperial College London, London, UK
| | - Blanche Schwappach
- Department of Molecular Biology, Centre for Biochemistry and Molecular Cell Biology, Heart Research Centre Göttingen, University Medicine Göttingen, Göttingen, Germany
| | - Guy A Rutter
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Imperial College London, London, UK
| | - Waljit S Dhillo
- Section of Endocrinology and Investigative Medicine, Division of Diabetes, Endocrinology and Metabolism, Imperial College London, London, UK
| | - James Gardiner
- Section of Endocrinology and Investigative Medicine, Division of Diabetes, Endocrinology and Metabolism, Imperial College London, London, UK
| |
Collapse
|
8
|
Nguyen-Tu MS, Nivoit P, Oréa V, Lemoine S, Acquaviva C, Pagnon-Minot A, Fromy B, Sethi JK, Sigaudo-Roussel D. Inflammation-linked adaptations in dermal microvascular reactivity accompany the development of obesity and type 2 diabetes. Int J Obes (Lond) 2018; 43:556-566. [PMID: 30006585 PMCID: PMC6223541 DOI: 10.1038/s41366-018-0148-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Revised: 05/26/2018] [Accepted: 06/08/2018] [Indexed: 01/04/2023]
Abstract
Background/Objectives The increased prevalence of obesity has prompted great strides in our understanding of specific adipose depots and their involvement in cardio-metabolic health. However, the impact of obesity on dermal white adipose tissue (dWAT) and dermal microvascular functionality remains unclear. This study aimed to investigate the temporal changes that occur in dWAT and dermal microvascular functionality during the development of diet-induced obesity and type 2 diabetes in mice. Methods Metabolic phenotyping of a murine model of hypercaloric diet (HCD)-induced obesity and type 2 diabetes was performed at three time points that reflected three distinct stages of disease development; 2 weeks of HCD-overweight-metabolically healthy, 4 weeks of HCD-obese-prediabetic and 12 weeks of HCD-obese-type 2 diabetic mice. Expansion of dWAT was characterized histologically, and changes in dermal microvascular reactivity were assessed in response to pressure and the vasodilators SNP and Ach. Results HCD resulted in a progressive expansion of dWAT and increased expression of pro-inflammatory markers (IL1β and COX-2). Impairments in pressure-induced (PIV) and Ach-induced (endothelium-dependent) vasodilation occurred early, in overweight-metabolically healthy mice. Residual vasodilatory responses were NOS-independent but sensitive to COX inhibition. These changes were associated with reductions in NO and adiponectin bioavailability, and rescued by exogenous adiponectin or hyperinsulinemia. Obese-prediabetic mice continued to exhibit impaired Ach-dependent vasodilation but PIV appeared normalized. This normalization coincided with elevated endogenous adiponectin and insulin levels, and was sensitive to NOS, COX and PI3K, inhibition. In obese-type 2 diabetic mice, both Ach-stimulated and pressure-induced vasodilatory responses were increased through enhanced COX-2-dependent prostaglandin response. Conclusions We demonstrate that the development of obesity, metabolic dysfunction and type 2 diabetes, in HCD-fed mice, is accompanied by increased dermal adiposity and associated metaflammation in dWAT. Importantly, these temporal changes are also linked to disease stage-specific dermal microvascular reactivity, which may reflect adaptive mechanisms driven by metaflammation.
Collapse
Affiliation(s)
- Marie-Sophie Nguyen-Tu
- LBTI, UMR CNRS 5305, 69367, Lyon Cedex 07, France.,University of Lyon 1, 69367, Lyon Cedex 07, France
| | - Pierre Nivoit
- LBTI, UMR CNRS 5305, 69367, Lyon Cedex 07, France.,University of Lyon 1, 69367, Lyon Cedex 07, France
| | - Valérie Oréa
- LBTI, UMR CNRS 5305, 69367, Lyon Cedex 07, France.,University of Lyon 1, 69367, Lyon Cedex 07, France
| | | | - Cécile Acquaviva
- LBTI, UMR CNRS 5305, 69367, Lyon Cedex 07, France.,Centre de Biologie et Pathologie Est, University Hospital, Hospices Civils de Lyon, 69677, Bron, France
| | | | - Bérengère Fromy
- LBTI, UMR CNRS 5305, 69367, Lyon Cedex 07, France.,University of Lyon 1, 69367, Lyon Cedex 07, France
| | - Jaswinder K Sethi
- Faculty of Medicine, University of Southampton, Institute of Developmental Sciences Building, Southampton General Hospital, Southampton, SO16 6YD, UK. .,National Institute for Health Research Southampton Biomedical Research Centre, University Hospital Southampton NHS Foundation Trust, Southampton General Hospital, Southampton, SO16 6YD, UK. .,Institute for Life Sciences, Life Sciences Building 85, University of Southampton, Highfield, Southampton, SO17 1BJ, UK.
| | - Dominique Sigaudo-Roussel
- LBTI, UMR CNRS 5305, 69367, Lyon Cedex 07, France. .,University of Lyon 1, 69367, Lyon Cedex 07, France.
| |
Collapse
|
9
|
Nguyen-Tu MS, da Silva Xavier G, Leclerc I, Rutter GA. Transcription factor-7-like 2 ( TCF7L2) gene acts downstream of the Lkb1/ Stk11 kinase to control mTOR signaling, β cell growth, and insulin secretion. J Biol Chem 2018; 293:14178-14189. [PMID: 29967064 PMCID: PMC6130960 DOI: 10.1074/jbc.ra118.003613] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Revised: 06/15/2018] [Indexed: 12/25/2022] Open
Abstract
Variants in the transcription factor-7–like 2 (TCF7L2/TCF4) gene, involved in Wnt signaling, are associated with type 2 diabetes. Loss of Tcf7l2 selectively from the β cell in mice has previously been shown to cause glucose intolerance and to lower β cell mass. Deletion of the tumor suppressor liver kinase B1 (LKB1/STK11) leads to β cell hyperplasia and enhanced glucose-stimulated insulin secretion, providing a convenient genetic model for increased β cell growth and function. The aim of this study was to explore the possibility that Tcf7l2 may be required for the effects of Lkb1 deletion on insulin secretion in the mouse β cell. Mice bearing floxed Lkb1 and/or Tcf7l2 alleles were bred with knockin mice bearing Cre recombinase inserted at the Ins1 locus (Ins1Cre), allowing highly β cell–selective deletion of either or both genes. Oral glucose tolerance was unchanged by the further deletion of a single Tcf7l2 allele in these cells. By contrast, mice lacking both Tcf7l2 alleles on this background showed improved oral glucose tolerance and insulin secretion in vivo and in vitro compared with mice lacking a single Tcf7l2 allele. Biallelic Tcf7l2 deletion also enhanced β cell proliferation, increased β cell mass, and caused changes in polarity as revealed by the “rosette-like” arrangement of β cells. Tcf7l2 deletion also increased signaling by mammalian target of rapamycin (mTOR), augmenting phospho-ribosomal S6 levels. We identified a novel signaling mechanism through which a modifier gene, Tcf7l2, lies on a pathway through which LKB1 acts in the β cell to restrict insulin secretion.
Collapse
Affiliation(s)
- Marie-Sophie Nguyen-Tu
- From the Section of Cell Biology and Functional Genomics and Pancreatic Islet and Diabetes Consortium, Division of Diabetes, Endocrinology and Metabolism, Imperial Centre for Translational and Experimental Medicine, Department of Medicine, Imperial College London, London W12 0NN, United Kingdom
| | - Gabriela da Silva Xavier
- From the Section of Cell Biology and Functional Genomics and Pancreatic Islet and Diabetes Consortium, Division of Diabetes, Endocrinology and Metabolism, Imperial Centre for Translational and Experimental Medicine, Department of Medicine, Imperial College London, London W12 0NN, United Kingdom
| | - Isabelle Leclerc
- From the Section of Cell Biology and Functional Genomics and Pancreatic Islet and Diabetes Consortium, Division of Diabetes, Endocrinology and Metabolism, Imperial Centre for Translational and Experimental Medicine, Department of Medicine, Imperial College London, London W12 0NN, United Kingdom
| | - Guy A Rutter
- From the Section of Cell Biology and Functional Genomics and Pancreatic Islet and Diabetes Consortium, Division of Diabetes, Endocrinology and Metabolism, Imperial Centre for Translational and Experimental Medicine, Department of Medicine, Imperial College London, London W12 0NN, United Kingdom
| |
Collapse
|
10
|
Martinez-Sanchez A, Nguyen-Tu MS, Cebola I, Yavari A, Marchetti P, Piemonti L, de Koning E, Shapiro AMJ, Johnson P, Sakamoto K, Smith DM, Leclerc I, Ashrafian H, Ferrer J, Rutter GA. MiR-184 expression is regulated by AMPK in pancreatic islets. FASEB J 2018; 32:2587-2600. [PMID: 29269398 PMCID: PMC6207280 DOI: 10.1096/fj.201701100r] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
AMPK is a critical energy sensor and target for widely used antidiabetic drugs. In β cells, elevated glucose concentrations lower AMPK activity, and the ablation of both catalytic subunits [β-cell–specific AMPK double-knockout (βAMPKdKO) mice] impairs insulin secretion in vivo and β-cell identity. MicroRNAs (miRNAs) are small RNAs that silence gene expression that are essential for pancreatic β-cell function and identity and altered in diabetes. Here, we have explored the miRNAs acting downstream of AMPK in mouse and human β cells. We identified 14 down-regulated and 9 up-regulated miRNAs in βAMPKdKO vs. control islets. Gene ontology analysis of targeted transcripts revealed enrichment in pathways important for β-cell function and identity. The most down-regulated miRNA was miR-184 (miR-184-3p), an important regulator of β-cell function and compensatory expansion that is controlled by glucose and reduced in diabetes. We demonstrate that AMPK is a potent regulator and an important mediator of the negative effects of glucose on miR-184 expression. Additionally, we reveal sexual dimorphism in miR-184 expression in mouse and human islets. Collectively, these data demonstrate that glucose-mediated changes in AMPK activity are central for the regulation of miR-184 and other miRNAs in islets and provide a link between energy status and gene expression in β cells.—Martinez-Sanchez, A., Nguyen-Tu, M.-S., Cebola, I., Yavari, A., Marchetti, P., Piemonti, L., de Koning, E., Shapiro, A. M. J., Johnson, P., Sakamoto, K., Smith, D. M., Leclerc, I., Ashrafian, H., Ferrer, J., Rutter, G. A. MiR-184 expression is regulated by AMPK in pancreatic islets.
Collapse
Affiliation(s)
- Aida Martinez-Sanchez
- Section of Cell Biology and Functional Genomics Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, Imperial College London, London, United Kingdom
| | - Marie-Sophie Nguyen-Tu
- Section of Cell Biology and Functional Genomics Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, Imperial College London, London, United Kingdom
| | - Ines Cebola
- Beta Cell Genome Regulation Laboratory, Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, Imperial College London, London, United Kingdom
| | - Arash Yavari
- Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Piero Marchetti
- Department of Endocrinology and Metabolism, University of Pisa, Pisa, Italy
| | - Lorenzo Piemonti
- San Raffaele Diabetes Research Institute (SR-DRI), Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) San Raffaele Scientific Institute, Milan, Italy.,Vita-Salute San Raffaele University, Milan, Italy
| | - Eelco de Koning
- Hubrecht Institute, Utrecht, The Netherlands.,Department of Medicine, Leiden University Medical Center, Leiden, The Netherlands
| | - A M James Shapiro
- Clinical Islet Laboratory and Clinical Islet Transplant Program, University of Alberta, Edmonton, Alberta, Canada
| | - Paul Johnson
- Nuffield Department of Surgical Sciences, University of Oxford, Oxford, United Kingdom
| | - Kei Sakamoto
- Nestle Institute of Health Sciences, Lausanne, Switzerland
| | - David M Smith
- AstraZeneca Research and Development, Innovative Medicines and Early Development, Discovery Sciences, Cambridge, United Kingdom
| | - Isabelle Leclerc
- Section of Cell Biology and Functional Genomics Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, Imperial College London, London, United Kingdom
| | - Houman Ashrafian
- Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Jorge Ferrer
- Beta Cell Genome Regulation Laboratory, Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, Imperial College London, London, United Kingdom
| | - Guy A Rutter
- Section of Cell Biology and Functional Genomics Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, Imperial College London, London, United Kingdom
| |
Collapse
|
11
|
Mitchell RK, Nguyen-Tu MS, Chabosseau P, Callingham RM, Pullen TJ, Cheung R, Leclerc I, Hodson DJ, Rutter GA. The transcription factor Pax6 is required for pancreatic β cell identity, glucose-regulated ATP synthesis, and Ca 2+ dynamics in adult mice. J Biol Chem 2017; 292:8892-8906. [PMID: 28377501 PMCID: PMC5448123 DOI: 10.1074/jbc.m117.784629] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Revised: 04/03/2017] [Indexed: 12/20/2022] Open
Abstract
Heterozygous mutations in the human paired box gene PAX6 lead to impaired glucose tolerance. Although embryonic deletion of the Pax6 gene in mice leads to loss of most pancreatic islet cell types, the functional consequences of Pax6 loss in adults are poorly defined. Here we developed a mouse line in which Pax6 was selectively inactivated in β cells by crossing animals with floxed Pax6 alleles to mice expressing the inducible Pdx1CreERT transgene. Pax6 deficiency, achieved by tamoxifen injection, caused progressive hyperglycemia. Although β cell mass was preserved 8 days post-injection, total insulin content and insulin:chromogranin A immunoreactivity were reduced by ∼60%, and glucose-stimulated insulin secretion was eliminated. RNA sequencing and quantitative real-time PCR analyses revealed that, although the expression of key β cell genes, including Ins2, Slc30a8, MafA, Slc2a2, G6pc2, and Glp1r, was reduced after Pax6 deletion, that of several genes that are usually selectively repressed (“disallowed”) in β cells, including Slc16a1, was increased. Assessed in intact islets, glucose-induced ATP:ADP increases were significantly reduced (p < 0.05) in βPax6KO versus control β cells, and the former displayed attenuated increases in cytosolic Ca2+. Unexpectedly, glucose-induced increases in intercellular connectivity were enhanced after Pax6 deletion, consistent with increases in the expression of the glucose sensor glucokinase, but decreases in that of two transcription factors usually expressed in fully differentiated β-cells, Pdx1 and Nkx6.1, were observed in islet “hub” cells. These results indicate that Pax6 is required for the functional identity of adult β cells. Furthermore, deficiencies in β cell glucose sensing are likely to contribute to defective insulin secretion in human carriers of PAX6 mutations.
Collapse
Affiliation(s)
- Ryan K Mitchell
- From the Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology, and Metabolism, Imperial College London, Du Cane Road, London W12 0NN, United Kingdom
| | - Marie-Sophie Nguyen-Tu
- From the Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology, and Metabolism, Imperial College London, Du Cane Road, London W12 0NN, United Kingdom
| | - Pauline Chabosseau
- From the Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology, and Metabolism, Imperial College London, Du Cane Road, London W12 0NN, United Kingdom
| | - Rebecca M Callingham
- From the Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology, and Metabolism, Imperial College London, Du Cane Road, London W12 0NN, United Kingdom
| | - Timothy J Pullen
- From the Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology, and Metabolism, Imperial College London, Du Cane Road, London W12 0NN, United Kingdom
| | - Rebecca Cheung
- From the Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology, and Metabolism, Imperial College London, Du Cane Road, London W12 0NN, United Kingdom
| | - Isabelle Leclerc
- From the Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology, and Metabolism, Imperial College London, Du Cane Road, London W12 0NN, United Kingdom
| | - David J Hodson
- From the Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology, and Metabolism, Imperial College London, Du Cane Road, London W12 0NN, United Kingdom, .,the Institute of Metabolism and Systems Research and Centre of Membrane Proteins and Receptors, University of Birmingham, Edgbaston B15 2TT, United Kingdom, and.,the Centre for Endocrinology, Diabetes, and Metabolism, Birmingham Health Partners, Birmingham B15 2TH, United Kingdom
| | - Guy A Rutter
- From the Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology, and Metabolism, Imperial College London, Du Cane Road, London W12 0NN, United Kingdom,
| |
Collapse
|
12
|
Mehta ZB, Johnston NR, Nguyen-Tu MS, Broichhagen J, Schultz P, Larner DP, Leclerc I, Trauner D, Rutter GA, Hodson DJ. Remote control of glucose homeostasis in vivo using photopharmacology. Sci Rep 2017; 7:291. [PMID: 28331198 PMCID: PMC5428208 DOI: 10.1038/s41598-017-00397-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [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: 08/15/2016] [Accepted: 02/21/2017] [Indexed: 01/26/2023] Open
Abstract
Photopharmacology describes the use of light to precisely deliver drug activity in space and time. Such approaches promise to improve drug specificity by reducing off-target effects. As a proof-of-concept, we have subjected the fourth generation photoswitchable sulfonylurea JB253 to comprehensive toxicology assessment, including mutagenicity and maximum/repeated tolerated dose studies, as well as in vivo testing in rodents. Here, we show that JB253 is well-tolerated with minimal mutagenicity and can be used to optically-control glucose homeostasis in anesthetized mice following delivery of blue light to the pancreas. These studies provide the first demonstration that photopharmacology may one day be applicable to the light-guided treatment of type 2 diabetes and other metabolic disease states in vivo in humans.
Collapse
Affiliation(s)
- Zenobia B Mehta
- Section of Cell Biology and Functional Genomics, Department of Medicine, Imperial College London, London, W12 0NN, UK
| | - Natalie R Johnston
- Section of Cell Biology and Functional Genomics, Department of Medicine, Imperial College London, London, W12 0NN, UK
| | - Marie-Sophie Nguyen-Tu
- Section of Cell Biology and Functional Genomics, Department of Medicine, Imperial College London, London, W12 0NN, UK
| | - Johannes Broichhagen
- Department of Chemistry and Center for Integrated Protein Science, LMU Munich, Munich, Germany
- Max-Planck Institute for Medical Research, Jahnstr. 29, 69120, Heidelberg, Germany
| | - Peter Schultz
- Department of Chemistry and Center for Integrated Protein Science, LMU Munich, Munich, Germany
| | - Dean P Larner
- Institute of Metabolism and Systems Research (IMSR) and Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham, Edgbaston, B15 2TT, UK
- Centre for Endocrinology, Diabetes and Metabolism (CEDAM), Birmingham Health Partners, Birmingham, B15 2TH, UK
| | - Isabelle Leclerc
- Section of Cell Biology and Functional Genomics, Department of Medicine, Imperial College London, London, W12 0NN, UK
| | - Dirk Trauner
- Department of Chemistry and Center for Integrated Protein Science, LMU Munich, Munich, Germany.
| | - Guy A Rutter
- Section of Cell Biology and Functional Genomics, Department of Medicine, Imperial College London, London, W12 0NN, UK.
| | - David J Hodson
- Institute of Metabolism and Systems Research (IMSR) and Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham, Edgbaston, B15 2TT, UK.
- Centre for Endocrinology, Diabetes and Metabolism (CEDAM), Birmingham Health Partners, Birmingham, B15 2TH, UK.
| |
Collapse
|
13
|
Yavari A, Stocker CJ, Ghaffari S, Wargent ET, Steeples V, Czibik G, Pinter K, Bellahcene M, Woods A, Martínez de Morentin PB, Cansell C, Lam BYH, Chuster A, Petkevicius K, Nguyen-Tu MS, Martinez-Sanchez A, Pullen TJ, Oliver PL, Stockenhuber A, Nguyen C, Lazdam M, O'Dowd JF, Harikumar P, Tóth M, Beall C, Kyriakou T, Parnis J, Sarma D, Katritsis G, Wortmann DDJ, Harper AR, Brown LA, Willows R, Gandra S, Poncio V, de Oliveira Figueiredo MJ, Qi NR, Peirson SN, McCrimmon RJ, Gereben B, Tretter L, Fekete C, Redwood C, Yeo GSH, Heisler LK, Rutter GA, Smith MA, Withers DJ, Carling D, Sternick EB, Arch JRS, Cawthorne MA, Watkins H, Ashrafian H. Chronic Activation of γ2 AMPK Induces Obesity and Reduces β Cell Function. Cell Metab 2016; 23:821-36. [PMID: 27133129 PMCID: PMC4873618 DOI: 10.1016/j.cmet.2016.04.003] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Revised: 03/01/2016] [Accepted: 04/01/2016] [Indexed: 12/02/2022]
Abstract
Despite significant advances in our understanding of the biology determining systemic energy homeostasis, the treatment of obesity remains a medical challenge. Activation of AMP-activated protein kinase (AMPK) has been proposed as an attractive strategy for the treatment of obesity and its complications. AMPK is a conserved, ubiquitously expressed, heterotrimeric serine/threonine kinase whose short-term activation has multiple beneficial metabolic effects. Whether these translate into long-term benefits for obesity and its complications is unknown. Here, we observe that mice with chronic AMPK activation, resulting from mutation of the AMPK γ2 subunit, exhibit ghrelin signaling-dependent hyperphagia, obesity, and impaired pancreatic islet insulin secretion. Humans bearing the homologous mutation manifest a congruent phenotype. Our studies highlight that long-term AMPK activation throughout all tissues can have adverse metabolic consequences, with implications for pharmacological strategies seeking to chronically activate AMPK systemically to treat metabolic disease.
Collapse
Affiliation(s)
- Arash Yavari
- Experimental Therapeutics, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DU, UK; Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DU, UK; Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK.
| | - Claire J Stocker
- The Buckingham Institute for Translational Medicine, University of Buckingham, Buckingham MK18 1EG, UK
| | - Sahar Ghaffari
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DU, UK; Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | - Edward T Wargent
- The Buckingham Institute for Translational Medicine, University of Buckingham, Buckingham MK18 1EG, UK
| | - Violetta Steeples
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DU, UK; Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | - Gabor Czibik
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DU, UK; Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | - Katalin Pinter
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DU, UK; Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | - Mohamed Bellahcene
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DU, UK; Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | - Angela Woods
- Cellular Stress Group, MRC Clinical Sciences Centre, Imperial College London, London SW7 2AZ, UK
| | | | - Céline Cansell
- Rowett Institute of Nutrition and Health, University of Aberdeen, Aberdeen AB25 2ZD, UK
| | - Brian Y H Lam
- University of Cambridge Metabolic Research Laboratories, Wellcome Trust-MRC Institute of Metabolic Science, Cambridge CB2 0QQ, UK
| | - André Chuster
- Pos Graduação Ciências Médicas, Faculdade Ciências Médicas, Universidade Federal de Minas Gerais, Belo Horizonte-MG 31270-901, Brazil
| | - Kasparas Petkevicius
- University of Cambridge Metabolic Research Laboratories, Wellcome Trust-MRC Institute of Metabolic Science, Cambridge CB2 0QQ, UK
| | - Marie-Sophie Nguyen-Tu
- Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology, and Metabolism, Imperial College London, London SW7 2AZ, UK
| | - Aida Martinez-Sanchez
- Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology, and Metabolism, Imperial College London, London SW7 2AZ, UK
| | - Timothy J Pullen
- Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology, and Metabolism, Imperial College London, London SW7 2AZ, UK
| | - Peter L Oliver
- MRC Functional Genomics Unit, Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford OX1 3PT, UK
| | - Alexander Stockenhuber
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DU, UK; Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | - Chinh Nguyen
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DU, UK; Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | - Merzaka Lazdam
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DU, UK
| | - Jacqueline F O'Dowd
- The Buckingham Institute for Translational Medicine, University of Buckingham, Buckingham MK18 1EG, UK
| | - Parvathy Harikumar
- The Buckingham Institute for Translational Medicine, University of Buckingham, Buckingham MK18 1EG, UK
| | - Mónika Tóth
- Department of Endocrine Neurobiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest 1083, Hungary
| | - Craig Beall
- Cardiovascular and Diabetes Medicine, Medical Research Institute, University of Dundee, Dundee DD1 9SY, UK
| | - Theodosios Kyriakou
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DU, UK; Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | - Julia Parnis
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DU, UK; Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | - Dhruv Sarma
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DU, UK; Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | - George Katritsis
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DU, UK; Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | - Diana D J Wortmann
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DU, UK; Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | - Andrew R Harper
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DU, UK; Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | - Laurence A Brown
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, OX3 9DU, UK
| | - Robin Willows
- Cellular Stress Group, MRC Clinical Sciences Centre, Imperial College London, London SW7 2AZ, UK
| | - Silvia Gandra
- Pos Graduação Ciências Médicas, Faculdade Ciências Médicas, Universidade Federal de Minas Gerais, Belo Horizonte-MG 31270-901, Brazil
| | - Victor Poncio
- Universidade Estadual de Campinas, Campinas-SP 13083-970, Brazil
| | | | - Nathan R Qi
- Department of Internal Medicine, Division of Metabolism, Endocrinology, and Diabetes, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Stuart N Peirson
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, OX3 9DU, UK
| | - Rory J McCrimmon
- Cardiovascular and Diabetes Medicine, Medical Research Institute, University of Dundee, Dundee DD1 9SY, UK
| | - Balázs Gereben
- Department of Endocrine Neurobiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest 1083, Hungary
| | - László Tretter
- Department of Medical Biochemistry, Semmelweis University, Budapest 1085, Hungary; MTA-SE Laboratory for Neurobiochemistry, Semmelweis University, Budapest 1085, Hungary
| | - Csaba Fekete
- Department of Endocrine Neurobiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest 1083, Hungary; Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, Tupper Research Institute, Tufts Medical Center, Boston, MA 02111, USA
| | - Charles Redwood
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DU, UK; Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | - Giles S H Yeo
- University of Cambridge Metabolic Research Laboratories, Wellcome Trust-MRC Institute of Metabolic Science, Cambridge CB2 0QQ, UK
| | - Lora K Heisler
- Rowett Institute of Nutrition and Health, University of Aberdeen, Aberdeen AB25 2ZD, UK
| | - Guy A Rutter
- Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology, and Metabolism, Imperial College London, London SW7 2AZ, UK
| | - Mark A Smith
- Metabolic Signalling Group, MRC Clinical Sciences Centre, Imperial College London, London W12 0NN, UK
| | - Dominic J Withers
- Metabolic Signalling Group, MRC Clinical Sciences Centre, Imperial College London, London W12 0NN, UK
| | - David Carling
- Cellular Stress Group, MRC Clinical Sciences Centre, Imperial College London, London SW7 2AZ, UK
| | - Eduardo B Sternick
- Pos Graduação Ciências Médicas, Faculdade Ciências Médicas, Universidade Federal de Minas Gerais, Belo Horizonte-MG 31270-901, Brazil
| | - Jonathan R S Arch
- The Buckingham Institute for Translational Medicine, University of Buckingham, Buckingham MK18 1EG, UK
| | - Michael A Cawthorne
- The Buckingham Institute for Translational Medicine, University of Buckingham, Buckingham MK18 1EG, UK
| | - Hugh Watkins
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DU, UK; Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | - Houman Ashrafian
- Experimental Therapeutics, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DU, UK; Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DU, UK; Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK; Experimental Therapeutics, Clinical Science Group, New Medicines, UCB Pharma S.A., Slough, Berkshire SL1 3WE, UK.
| |
Collapse
|
14
|
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.
Collapse
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.
| |
Collapse
|
15
|
Martinez-Sanchez A, Nguyen-Tu MS, Rutter GA. DICER Inactivation Identifies Pancreatic β-Cell "Disallowed" Genes Targeted by MicroRNAs. Mol Endocrinol 2015; 29:1067-79. [PMID: 26038943 PMCID: PMC4484783 DOI: 10.1210/me.2015-1059] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Pancreatic β-cells are the body's sole source of circulating insulin and essential for the maintenance of blood glucose homeostasis. Levels of up to 66 “disallowed” genes, which are strongly expressed and play housekeeping roles in most other mammalian tissues, are unusually low in β-cells. The molecular mechanisms involved in repressing these genes are largely unknown. Here, we explore the role in gene disallowance of microRNAs (miRNAs), a type of small noncoding RNAs that silence gene expression at the posttranscriptional level and are essential for β-cell development and function. To selectively deplete miRNAs from adult β-cells, the miRNA-processing enzyme DICER was inactivated by deletion of the RNase III domain with a tamoxifen-inducible Pdx1CreER transgene. In this model, β-cell dysfunction was apparent 2 weeks after recombination and preceded a decrease in insulin content and loss of β-cell mass. Of the 14 disallowed genes studied, quantitative RT-quantitative real-time PCR revealed that 6 genes (Fcgrt, Igfbp4, Maf, Oat, Pdgfra, and Slc16a1) were up-regulated (1.4- to 2.1-fold, P < .05) at this early stage. Expression of luciferase constructs bearing the 3′-untranslated regions of the corresponding mRNAs in wild-type or DICER-null β-cells demonstrated that Fcgrt, Oat, and Pdgfra are miRNA direct targets. We thus reveal a role for miRNAs in the regulation of disallowed genes in β-cells and provide evidence for a novel means through which noncoding RNAs control the functional identity of these cells independently of actions on β-cell mass.
Collapse
Affiliation(s)
- Aida Martinez-Sanchez
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Imperial College London, London W12 0NN, United Kingdom
| | - Marie-Sophie Nguyen-Tu
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Imperial College London, London W12 0NN, United Kingdom
| | - Guy A Rutter
- Section of Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Imperial College London, London W12 0NN, United Kingdom
| |
Collapse
|
16
|
Kone M, Pullen TJ, Sun G, Ibberson M, Martinez-Sanchez A, Sayers S, Nguyen-Tu MS, Kantor C, Swisa A, Dor Y, Gorman T, Ferrer J, Thorens B, Reimann F, Gribble F, McGinty JA, Chen L, French PM, Birzele F, Hildebrandt T, Uphues I, Rutter GA. LKB1 and AMPK differentially regulate pancreatic β-cell identity. FASEB J 2014; 28:4972-85. [PMID: 25070369 PMCID: PMC4377859 DOI: 10.1096/fj.14-257667] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Accepted: 07/14/2014] [Indexed: 12/15/2022]
Abstract
Fully differentiated pancreatic β cells are essential for normal glucose homeostasis in mammals. Dedifferentiation of these cells has been suggested to occur in type 2 diabetes, impairing insulin production. Since chronic fuel excess ("glucotoxicity") is implicated in this process, we sought here to identify the potential roles in β-cell identity of the tumor suppressor liver kinase B1 (LKB1/STK11) and the downstream fuel-sensitive kinase, AMP-activated protein kinase (AMPK). Highly β-cell-restricted deletion of each kinase in mice, using an Ins1-controlled Cre, was therefore followed by physiological, morphometric, and massive parallel sequencing analysis. Loss of LKB1 strikingly (2.0-12-fold, E<0.01) increased the expression of subsets of hepatic (Alb, Iyd, Elovl2) and neuronal (Nptx2, Dlgap2, Cartpt, Pdyn) genes, enhancing glutamate signaling. These changes were partially recapitulated by the loss of AMPK, which also up-regulated β-cell "disallowed" genes (Slc16a1, Ldha, Mgst1, Pdgfra) 1.8- to 3.4-fold (E < 0.01). Correspondingly, targeted promoters were enriched for neuronal (Zfp206; P = 1.3 × 10(-33)) and hypoxia-regulated (HIF1; P = 2.5 × 10(-16)) transcription factors. In summary, LKB1 and AMPK, through only partly overlapping mechanisms, maintain β-cell identity by suppressing alternate pathways leading to neuronal, hepatic, and other characteristics. Selective targeting of these enzymes may provide a new approach to maintaining β-cell function in some forms of diabetes.
Collapse
Affiliation(s)
| | | | | | | | | | | | | | | | - Avital Swisa
- Department of Developmental Biology and Cancer Research, Institute for Medical Research Israel-Canada, Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Yuval Dor
- Department of Developmental Biology and Cancer Research, Institute for Medical Research Israel-Canada, Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Tracy Gorman
- AstraZeneca Diabetes and Obesity Drug Discovery, Alderley Edge, UK
| | - Jorge Ferrer
- Section of β-Cell Development, Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, and
| | - Bernard Thorens
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| | - Frank Reimann
- Metabolic Research Laboratories, University of Cambridge, Cambridge, UK and
| | - Fiona Gribble
- Metabolic Research Laboratories, University of Cambridge, Cambridge, UK and
| | - James A McGinty
- Photonics Group, Department of Physics, Imperial College London, London, UK
| | - Lingling Chen
- Photonics Group, Department of Physics, Imperial College London, London, UK
| | - Paul M French
- Photonics Group, Department of Physics, Imperial College London, London, UK
| | | | | | - Ingo Uphues
- Boehringer Ingelheim Pharma, Ingelheim, Germany
| | | |
Collapse
|
17
|
Lemoine S, Guebre-Egziabher F, Sens F, Nguyen-Tu MS, Juillard L, Dubourg L, Hadj-Aissa A. Accuracy of GFR estimation in obese patients. Clin J Am Soc Nephrol 2014; 9:720-7. [PMID: 24482068 DOI: 10.2215/cjn.03610413] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
BACKGROUND AND OBJECTIVES Adequate estimation of renal function in obese patients is essential for the classification of patients in CKD category as well as the dose adjustment of drugs. However, the body size descriptor for GFR indexation is still debatable, and formulas are not validated in patients with extreme variations of weight. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS This study included 209 stages 1-5 CKD obese patients referred to the Department of Renal Function Study at the University Hospital in Lyon between 2010 and 2013 because of suspected renal dysfunction. GFR was estimated with the Chronic Kidney Disease and Epidemiology equation (CKD-EPI) and measured with a gold standard method (inulin or iohexol) not indexed (mGFR) or indexed to body surface area determined by the Dubois and Dubois formula with either real (mGFRr) or ideal (mGFRi) body weight. Mean bias (eGFR-mGFR), precision, and accuracy of mGFR were compared with the results obtained for nonobese participants (body mass index between 18.5 and 24.9) who had a GFR measurement during the same period of time. RESULTS Mean mGFRr (51.6 ± 24.2 ml/min per 1.73 m(2)) was significantly lower than mGFR, mGFRi, and eGFRCKD-EPI. eGFRCKD-EPI had less bias with mGFR (0.29; -1.7 to 2.3) and mGFRi (-1.62; -3.1 to 0.45) compared with mGFRr (8.7; 7 to 10). This result was confirmed with better accuracy for the whole cohort (78% for mGFR, 84% for mGFRi, and 72% for mGFRr) and participants with CKD stages 3-5. Moreover, the Bland Altman plot showed better agreement between mGFR and eGFRCKD-EPI. The bias between eGFRCKD-EPI and mGFRr was greater in obese than nonobese participants (8.7 versus 0.58, P<0.001). CONCLUSIONS This study shows that, in obese CKD patients, the performance of eGFRCKD-EPI is good for GFR ≤ 60 ml/min per 1.73 m(2). Indexation of mGFR with body surface area using ideal body weight gives less bias than mGFR scaled with body surface area using real body weight.
Collapse
Affiliation(s)
- Sandrine Lemoine
- Departments of Renal Function Study and, †Nephrology, Edouard Herriot Hospital, Hospices Civils de Lyon, Lyon, France;, ‡Institut National de la Santé et de la Recherche Médicale U1060, Laboratoire de Recherche en Cardiovasculaire, Métabolisme, Diabétologie et Nutrition, Lyon, France;, §University of Lyon, Université Lyon 1 Claude Bernard, Lyon, France, ‖Unité Mixte de Recherche 5305 Centre National de la Recherche Scientifique, Université Claude Bernard, Lyon, France
| | | | | | | | | | | | | |
Collapse
|
18
|
Nguyen-Tu MS, Begey AL, Decorps J, Boizot J, Sommer P, Fromy B, Sigaudo-Roussel D. Skin microvascular response to pressure load in obese mice. Microvasc Res 2013; 90:138-43. [PMID: 24120748 DOI: 10.1016/j.mvr.2013.10.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Revised: 09/06/2013] [Accepted: 10/02/2013] [Indexed: 10/26/2022]
Abstract
PURPOSE The role of obesity in the appearance of skin pressure ulcers remains controversial. The aim of the present study was to evaluate blood perfusion and related lesions after skin compression in obese mice. METHODS Sixty C57BL6 male mice were randomly assigned to a control or hypercalorific diet (HCD) for 2, 4 and 12weeks. Skin compression was induced by a magnetic force of 11 kPa overlying a subcutaneous metal plate and applied for 4h. Skin perfusion was examined using laser Doppler imaging before skin compression, immediately after compression release and 24h later. 24h after magnet removal, skin injuries were determined by photography. RESULTS A heterogeneous distribution of blood perfusion was observed using the colour-coded map of the skin perfusion on the compressed area. At 24-h post-compression release, 60% to 75% of the compressed area was ischaemic in the 2-week HCD group and in all the control groups compared to 35% in the 4- and 15% in the 12-week HCD groups. The lowest occurrence of skin lesion seen as skin redness or pressure-sores was observed in the 12- week HCD group (4%) compared to about 12% in either the control or the 2- and 4-week HCD groups. CONCLUSIONS This study suggests that there was no clear relationship between the extent of ischaemia and skin lesion occurrence after skin compression in short-duration obese mice. In contrast, it appears that long-duration obesity could reduce both ischaemia and skin lesions in response to skin compression through changes in skin structure.
Collapse
Affiliation(s)
- Marie-Sophie Nguyen-Tu
- UMR 5305 CNRS, 69 367 Lyon cedex 07, France; University of Lyon 1, 69 367 Lyon cedex 07, France
| | | | | | | | | | | | | |
Collapse
|