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Rosell M, Jones MC, Parker MG. Role of nuclear receptor corepressor RIP140 in metabolic syndrome. Biochim Biophys Acta Mol Basis Dis 2010; 1812:919-28. [PMID: 21193034 PMCID: PMC3117993 DOI: 10.1016/j.bbadis.2010.12.016] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2010] [Revised: 12/15/2010] [Accepted: 12/17/2010] [Indexed: 01/04/2023]
Abstract
Obesity and its associated complications, which can lead to the development of metabolic syndrome, are a worldwide major public health concern especially in developed countries where they have a very high prevalence. RIP140 is a nuclear coregulator with a pivotal role in controlling lipid and glucose metabolism. Genetically manipulated mice devoid of RIP140 are lean with increased oxygen consumption and are resistant to high-fat diet-induced obesity and hepatic steatosis with improved insulin sensitivity. Moreover, white adipocytes with targeted disruption of RIP140 express genes characteristic of brown fat including CIDEA and UCP1 while skeletal muscles show a shift in fibre type composition enriched in more oxidative fibres. Thus, RIP140 is a potential therapeutic target in metabolic disorders. In this article we will review the role of RIP140 in tissues relevant to the appearance and progression of the metabolic syndrome and discuss how the manipulation of RIP140 levels or activity might represent a therapeutic approach to combat obesity and associated metabolic disorders. This article is part of a Special Issue entitled: Translating nuclear receptors from health to disease.
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Affiliation(s)
- Meritxell Rosell
- Institute of Reproductive and Developmental Biology, Imperial College London, Faculty of Medicine, Hammersmith Campus 158 Du Cane Road, W12 0NN, UK.
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103
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Murrow BA, Hoehn KL. Mitochondrial regulation of insulin action. Int J Biochem Cell Biol 2010; 42:1936-9. [PMID: 20837159 DOI: 10.1016/j.biocel.2010.08.020] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2010] [Revised: 08/21/2010] [Accepted: 08/30/2010] [Indexed: 11/28/2022]
Abstract
Insulin resistance is the prodrome of many metabolic diseases and identifying ways to correct this pathological condition is a major goal for medical research. The foremost barrier to the development of new treatments is that the precise etiology of insulin resistance is uncertain. Recent studies suggest that changes in mitochondrial structure or function drive this condition, however much of this evidence is circumstantial. This Signaling Networks in Focus article provides a brief overview of known and speculative regulatory intersections whereby mitochondrial dysfunction at the levels of lipid oxidation, oxidative stress, calcium, adenine nucleotides, and protons may regulate insulin sensitivity. If mitochondrial dysfunction underlies the origins of metabolic disease then determining the precise molecular pathway will be essential for the development of new treatment and prevention strategies.
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Affiliation(s)
- Beverley A Murrow
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908, USA
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104
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Differences in muscle and adipose tissue gene expression and cardio-metabolic risk factors in the members of physical activity discordant twin pairs. PLoS One 2010; 5. [PMID: 20862330 PMCID: PMC2940764 DOI: 10.1371/journal.pone.0012609] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2010] [Accepted: 08/06/2010] [Indexed: 11/19/2022] Open
Abstract
High physical activity/aerobic fitness predicts low morbidity and mortality. Our aim was to identify the most up-regulated gene sets related to long-term physical activity vs. inactivity in skeletal muscle and adipose tissues and to obtain further information about their link with cardio-metabolic risk factors. We studied ten same-sex twin pairs (age range 50–74 years) who had been discordant for leisure-time physical activity for 30 years. The examinations included biopsies from m. vastus lateralis and abdominal subcutaneous adipose tissue. RNA was analyzed with the genome-wide Illumina Human WG-6 v3.0 Expression BeadChip. For pathway analysis we used Gene Set Enrichment Analysis utilizing active vs. inactive co-twin gene expression ratios. Our findings showed that among the physically active members of twin pairs, as compared to their inactive co-twins, gene expression in the muscle tissue samples was chronically up-regulated for the central pathways related to energy metabolism, including oxidative phosphorylation, lipid metabolism and supportive metabolic pathways. Up-regulation of these pathways was associated in particular with aerobic fitness and high HDL cholesterol levels. In fat tissue we found physical activity-associated increases in the expression of polyunsaturated fatty acid metabolism and branched-chain amino acid degradation gene sets both of which associated with decreased ‘high-risk’ ectopic body fat and plasma glucose levels. Consistent with other findings, plasma lipidomics analysis showed up-regulation of the triacylglycerols containing the polyunsaturated fatty acids. Our findings identified skeletal muscle and fat tissue pathways which are associated with the long-term physical activity and reduced cardio-metabolic disease risk, including increased aerobic fitness. In particular, improved skeletal muscle oxidative energy and lipid metabolism as well as changes in adipocyte function and redistribution of body fat are associated with reduced cardio-metabolic risk.
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105
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Niu W, Bilan PJ, Yu J, Gao J, Boguslavsky S, Schertzer JD, Chu G, Yao Z, Klip A. PKCε regulates contraction-stimulated GLUT4 traffic in skeletal muscle cells. J Cell Physiol 2010; 226:173-80. [DOI: 10.1002/jcp.22320] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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106
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Salvi N, Guellich A, Michelet P, Demoule A, Le Guen M, Renou L, Bonne G, Riou B, Langeron O, Coirault C. Upregulation of PPARbeta/delta is associated with structural and functional changes in the type I diabetes rat diaphragm. PLoS One 2010; 5:e11494. [PMID: 20628611 PMCID: PMC2900215 DOI: 10.1371/journal.pone.0011494] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2010] [Accepted: 06/14/2010] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND Diabetes mellitus is associated with alterations in peripheral striated muscles and cardiomyopathy. We examined diaphragmatic function and fiber composition and identified the role of peroxisome proliferator-activated receptors (PPAR alpha and beta/delta) as a factor involved in diaphragm muscle plasticity in response to type I diabetes. METHODOLOGY/PRINCIPAL FINDINGS Streptozotocin-treated rats were studied after 8 weeks and compared with their controls. Diaphragmatic strips were stimulated in vitro and mechanical and energetic variables were measured, cross bridge kinetics assessed, and the effects of fatigue and hypoxia evaluated. Morphometry, myosin heavy chain isoforms, PPAR alpha and beta/delta gene and protein expression were also assessed. Diabetes induced a decrease in maximum velocity of shortening (-14%, P<0.05) associated with a decrease in myosin ATPase activity (-49%, P<0.05), and an increase in force (+20%, P<0.05) associated with an increase in the number of cross bridges (+14%, P<0.05). These modifications were in agreement with a shift towards slow myosin heavy chain fibers and were associated with an upregulation of PPARbeta/delta (+314% increase in gene and +190% increase in protein expression, P<0.05). In addition, greater resistances to fatigue and hypoxia were observed in diabetic rats. CONCLUSIONS/SIGNIFICANCE Type I diabetes induced complex mechanical and energetic changes in the rat diaphragm and was associated with an up-regulation of PPARbeta/delta that could improve resistance to fatigue and hypoxia and favour the shift towards slow myosin heavy chain isoforms.
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Affiliation(s)
- Nadège Salvi
- UMRS INSERM 956, Institut de Myologie, IFR14, Université Pierre et Marie Curie-Paris 6, Paris, France
| | - Aziz Guellich
- UMRS INSERM 974, Institut de Myologie, IFR14, Université Pierre et Marie Curie-Paris 6, Paris, France
| | - Pierre Michelet
- UMRS INSERM 956, Institut de Myologie, IFR14, Université Pierre et Marie Curie-Paris 6, Paris, France
| | - Alexandre Demoule
- UMRS INSERM 974, Institut de Myologie, IFR14, Université Pierre et Marie Curie-Paris 6, Paris, France
- Department of Pneumology, Groupe hospitalier Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris (APHP), Paris, France
| | - Morgan Le Guen
- UMRS INSERM 956, Institut de Myologie, IFR14, Université Pierre et Marie Curie-Paris 6, Paris, France
- Department of Anesthesiology and Critical Care, Groupe hospitalier Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris (APHP), Paris, France
| | - Laure Renou
- UMR CNRS 7215, Institut de Myologie, IFR14, Université Pierre et Marie Curie-Paris 6, Paris, France
| | - Gisèle Bonne
- UMRS INSERM 974, Institut de Myologie, IFR14, Université Pierre et Marie Curie-Paris 6, Paris, France
- UMR CNRS 7215, Institut de Myologie, IFR14, Université Pierre et Marie Curie-Paris 6, Paris, France
- Department of Metabolic Biochemistry, Groupe hospitalier Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris (APHP), Paris, France
| | - Bruno Riou
- UMRS INSERM 956, Institut de Myologie, IFR14, Université Pierre et Marie Curie-Paris 6, Paris, France
- Department of Emergency Medicine and Surgery, Groupe hospitalier Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris (APHP), Paris, France
- * E-mail:
| | - Olivier Langeron
- UMRS INSERM 956, Institut de Myologie, IFR14, Université Pierre et Marie Curie-Paris 6, Paris, France
- Department of Anesthesiology and Critical Care, Groupe hospitalier Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris (APHP), Paris, France
| | - Catherine Coirault
- UMRS INSERM 974, Institut de Myologie, IFR14, Université Pierre et Marie Curie-Paris 6, Paris, France
- UMR CNRS 7215, Institut de Myologie, IFR14, Université Pierre et Marie Curie-Paris 6, Paris, France
- Department of Physiology, Hôpital de Bicêtre, APHP, Le Kremlin-Bicêtre, France
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Abstract
PURPOSE OF REVIEW Lipid accumulation in nonadipose tissues is increasingly recognized to contribute to organ injury through a process termed lipotoxicity, but whether this process occurs in the kidney is still uncertain. This article briefly summarizes the normal role of lipids in renal physiology and the current evidence linking excess lipids and lipotoxicity to renal dysfunction. RECENT FINDINGS Evidence suggesting that renal lipid accumulation and lipotoxicity may lead to kidney dysfunction has mounted significantly over recent years. Abnormal renal lipid content has been described in a number of animal models and has been successfully manipulated using pharmacologic or genetic strategies. There is some heterogeneity among studies with regard to the mechanisms, consequences, and localization of lipid accumulation in the kidney, explainable at least in part by inherent differences between animal models. The relevance of these findings for human pathophysiology remains to be established. SUMMARY Current knowledge on renal lipid physiology and pathophysiology is insufficient, but provides a strong foundation and incentive for further exploration. The future holds significant challenges in this area, especially with regard to applicability of research findings to the human kidney in vivo, but also the opportunity to transform our understanding of an array of kidney disorders.
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Affiliation(s)
- Ion Alexandru Bobulescu
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas 775390-8885, USA.
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108
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Kewalramani G, Bilan PJ, Klip A. Muscle insulin resistance: assault by lipids, cytokines and local macrophages. Curr Opin Clin Nutr Metab Care 2010; 13:382-90. [PMID: 20495453 DOI: 10.1097/mco.0b013e32833aabd9] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
PURPOSE OF REVIEW The present review outlines possible mechanisms by which high fatty acids, associated with high-fat diet and obesity, impose insulin resistance on glucose uptake into skeletal muscle. RECENT FINDINGS It is well established that muscle insulin resistance arises in conditions of high-fatty acid availability, and correlates with accumulation of triglycerides within skeletal muscle fibres. However, it is debated whether triglycerides or other lipid metabolites such as diacylglycerols and ceramides are directly responsible. These lipid metabolites can activate serine kinases that impair insulin signalling. Accumulation of acylcarnitines and reactive oxygen species could be additional causative agents of insulin resistance. Further, the precise defects in insulin signalling in muscle caused by high intramuscular lipid (i.e. lipotoxicity) remain unclear. In parallel, proinflammatory activation within the adipose tissue of obese and high-fat fed animals or humans causes muscle insulin resistance, and is ascribed to circulating inflammatory cytokines. Recent evidence also shows proinflammatory macrophages infiltrating muscle tissue and/or intermuscular adipose tissue, and there is growing evidence that fatty acids trigger macrophages to secrete factors that directly impair insulin actions. These factors are postulated to activate stress-signalling pathways in muscle that act on the same insulin-signalling components affected by lipotoxicity. SUMMARY Altered intramuscular lipid metabolism, circulating cytokines, and inflammatory macrophage infiltration of muscle tissue have been recently linked to muscle insulin resistance provoked by fatty acids. Each is analysed separately in this review, but they may act simultaneously and synergistically to render skeletal muscle insulin-resistant.
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