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Keller MP, Hudkins KL, Shalev A, Bhatnagar S, Kebede MA, Merrins MJ, Davis DB, Alpers CE, Kimple ME, Attie AD. What the BTBR/J mouse has taught us about diabetes and diabetic complications. iScience 2023; 26:107036. [PMID: 37360692 PMCID: PMC10285641 DOI: 10.1016/j.isci.2023.107036] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/28/2023] Open
Abstract
Human and mouse genetics have delivered numerous diabetogenic loci, but it is mainly through the use of animal models that the pathophysiological basis for their contribution to diabetes has been investigated. More than 20 years ago, we serendipidously identified a mouse strain that could serve as a model of obesity-prone type 2 diabetes, the BTBR (Black and Tan Brachyury) mouse (BTBR T+ Itpr3tf/J, 2018) carrying the Lepob mutation. We went on to discover that the BTBR-Lepob mouse is an excellent model of diabetic nephropathy and is now widely used by nephrologists in academia and the pharmaceutical industry. In this review, we describe the motivation for developing this animal model, the many genes identified and the insights about diabetes and diabetes complications derived from >100 studies conducted in this remarkable animal model.
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Affiliation(s)
- Mark P. Keller
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Kelly L. Hudkins
- Department of Pathology, University of Washington Medical Center, Seattle, WA 98195, USA
| | - Anath Shalev
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Alabama at Birmingham, Birmingham, AL 35294, UK
| | - Sushant Bhatnagar
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Alabama at Birmingham, Birmingham, AL 35294, UK
| | - Melkam A. Kebede
- School of Medical Sciences, Faculty of Medicine and Health, Charles Perkins Centre, University of Sydney, Camperdown, Sydney, NSW 2006, Australia
| | - Matthew J. Merrins
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA
- William S. Middleton Memorial Veterans Hospital, Madison, WI 53705, USA
| | - Dawn Belt Davis
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA
- William S. Middleton Memorial Veterans Hospital, Madison, WI 53705, USA
| | - Charles E. Alpers
- Department of Pathology, University of Washington Medical Center, Seattle, WA 98195, USA
| | - Michelle E. Kimple
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA
- William S. Middleton Memorial Veterans Hospital, Madison, WI 53705, USA
| | - Alan D. Attie
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
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Schwerbel K, Kamitz A, Krahmer N, Hallahan N, Jähnert M, Gottmann P, Lebek S, Schallschmidt T, Arends D, Schumacher F, Kleuser B, Haltenhof T, Heyd F, Gancheva S, Broman KW, Roden M, Joost HG, Chadt A, Al-Hasani H, Vogel H, Jonas W, Schürmann A. Immunity-related GTPase induces lipophagy to prevent excess hepatic lipid accumulation. J Hepatol 2020; 73:771-782. [PMID: 32376415 PMCID: PMC7957830 DOI: 10.1016/j.jhep.2020.04.031] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Revised: 04/08/2020] [Accepted: 04/16/2020] [Indexed: 12/19/2022]
Abstract
BACKGROUND & AIMS Currently, only a few genetic variants explain the heritability of fatty liver disease. Quantitative trait loci (QTL) analysis of mouse strains has identified the susceptibility locus Ltg/NZO (liver triglycerides from New Zealand obese [NZO] alleles) on chromosome 18 as associating with increased hepatic triglycerides. Herein, we aimed to identify genomic variants responsible for this association. METHODS Recombinant congenic mice carrying 5.3 Mbp of Ltg/NZO were fed a high-fat diet and characterized for liver fat. Bioinformatic analysis, mRNA profiles and electrophoretic mobility shift assays were performed to identify genes responsible for the Ltg/NZO phenotype. Candidate genes were manipulated in vivo by injecting specific microRNAs into C57BL/6 mice. Pulldown coupled with mass spectrometry-based proteomics and immunoprecipitation were performed to identify interaction partners of IFGGA2. RESULTS Through positional cloning, we identified 2 immunity-related GTPases (Ifgga2, Ifgga4) that prevent hepatic lipid storage. Expression of both murine genes and the human orthologue IRGM was significantly lower in fatty livers. Accordingly, liver-specific suppression of either Ifgga2 or Ifgga4 led to a 3-4-fold greater increase in hepatic fat content. In the liver of low-fat diet-fed mice, IFGGA2 localized to endosomes/lysosomes, while on a high-fat diet it associated with lipid droplets. Pulldown experiments and proteomics identified the lipase ATGL as a binding partner of IFGGA2 which was confirmed by co-immunoprecipitation. Both proteins partially co-localized with the autophagic marker LC3B. Ifgga2 suppression in hepatocytes reduced the amount of LC3B-II, whereas overexpression of Ifgga2 increased the association of LC3B with lipid droplets and decreased triglyceride storage. CONCLUSION IFGGA2 interacts with ATGL and protects against hepatic steatosis, most likely by enhancing the binding of LC3B to lipid droplets. LAY SUMMARY The genetic basis of non-alcoholic fatty liver disease remains incompletely defined. Herein, we identified members of the immunity-related GTPase family in mice and humans that act as regulators of hepatic fat accumulation, with links to autophagy. Overexpression of the gene Ifgga2 was shown to reduce hepatic lipid storage and could be a therapeutic target for the treatment of fatty liver disease.
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Affiliation(s)
- Kristin Schwerbel
- Department of Experimental Diabetology, German Institute of Human Nutrition Potsdam-Rehbruecke, D-14558 Nuthetal, Germany; German Center for Diabetes Research, D-85764 München-Neuherberg, Germany
| | - Anne Kamitz
- Department of Experimental Diabetology, German Institute of Human Nutrition Potsdam-Rehbruecke, D-14558 Nuthetal, Germany; German Center for Diabetes Research, D-85764 München-Neuherberg, Germany
| | - Natalie Krahmer
- German Center for Diabetes Research, D-85764 München-Neuherberg, Germany; Department of Proteomics and Signal Transduction, Max-Planck Institute of Biochemistry, D-82152 Martinsried, Germany; Institute for Diabetes and Obesity, Helmholtz Zentrum München, D-85764 München-Neuherberg, Germany
| | - Nicole Hallahan
- Department of Experimental Diabetology, German Institute of Human Nutrition Potsdam-Rehbruecke, D-14558 Nuthetal, Germany; German Center for Diabetes Research, D-85764 München-Neuherberg, Germany
| | - Markus Jähnert
- Department of Experimental Diabetology, German Institute of Human Nutrition Potsdam-Rehbruecke, D-14558 Nuthetal, Germany; German Center for Diabetes Research, D-85764 München-Neuherberg, Germany
| | - Pascal Gottmann
- Department of Experimental Diabetology, German Institute of Human Nutrition Potsdam-Rehbruecke, D-14558 Nuthetal, Germany; German Center for Diabetes Research, D-85764 München-Neuherberg, Germany
| | - Sandra Lebek
- German Center for Diabetes Research, D-85764 München-Neuherberg, Germany; Medical Faculty, Institute for Clinical Biochemistry and Pathobiochemistry, German Diabetes Center, Leibniz Center for Diabetes Research at Heinrich Heine University Düsseldorf, D-40225, Düsseldorf, Germany
| | - Tanja Schallschmidt
- German Center for Diabetes Research, D-85764 München-Neuherberg, Germany; Medical Faculty, Institute for Clinical Biochemistry and Pathobiochemistry, German Diabetes Center, Leibniz Center for Diabetes Research at Heinrich Heine University Düsseldorf, D-40225, Düsseldorf, Germany
| | - Danny Arends
- Animal Breeding Biology and Molecular Genetics, Albrecht Daniel Thaer-Institute of Agricultural and Horticultural Sciences, Humboldt-Universität zu Berlin, D-10117 Berlin, Germany
| | - Fabian Schumacher
- Institute of Nutritional Science, Department of Toxicology, University of Potsdam, D-14558 Nuthetal, Germany
| | - Burkhard Kleuser
- Institute of Nutritional Science, Department of Toxicology, University of Potsdam, D-14558 Nuthetal, Germany
| | - Tom Haltenhof
- Department of Biology, Chemistry, Pharmacy, Freie Universität Berlin, Institute of Chemistry and Biochemistry, Laboratory of RNA Biochemistry, D-14195 Berlin, Germany
| | - Florian Heyd
- Department of Biology, Chemistry, Pharmacy, Freie Universität Berlin, Institute of Chemistry and Biochemistry, Laboratory of RNA Biochemistry, D-14195 Berlin, Germany
| | - Sofiya Gancheva
- German Center for Diabetes Research, D-85764 München-Neuherberg, Germany; Institute for Clinical Diabetology, German Diabetes Center, Leibniz Institute for Diabetes Research, Heinrich-Heine University Düsseldorf, D-40225 Düsseldorf, Germany; Department of Endocrinology and Diabetology, Medical Faculty, Heinrich-Heine University, D-40225 Düsseldorf, Germany
| | - Karl W Broman
- Department of Biostatistics and Medical Informatics, University of Wisconsin, WI 53706 Madison, Wisconsin, United States
| | - Michael Roden
- German Center for Diabetes Research, D-85764 München-Neuherberg, Germany; Institute for Clinical Diabetology, German Diabetes Center, Leibniz Institute for Diabetes Research, Heinrich-Heine University Düsseldorf, D-40225 Düsseldorf, Germany; Department of Endocrinology and Diabetology, Medical Faculty, Heinrich-Heine University, D-40225 Düsseldorf, Germany
| | - Hans-Georg Joost
- Department of Experimental Diabetology, German Institute of Human Nutrition Potsdam-Rehbruecke, D-14558 Nuthetal, Germany; German Center for Diabetes Research, D-85764 München-Neuherberg, Germany
| | - Alexandra Chadt
- German Center for Diabetes Research, D-85764 München-Neuherberg, Germany; Medical Faculty, Institute for Clinical Biochemistry and Pathobiochemistry, German Diabetes Center, Leibniz Center for Diabetes Research at Heinrich Heine University Düsseldorf, D-40225, Düsseldorf, Germany
| | - Hadi Al-Hasani
- German Center for Diabetes Research, D-85764 München-Neuherberg, Germany; Medical Faculty, Institute for Clinical Biochemistry and Pathobiochemistry, German Diabetes Center, Leibniz Center for Diabetes Research at Heinrich Heine University Düsseldorf, D-40225, Düsseldorf, Germany
| | - Heike Vogel
- Department of Experimental Diabetology, German Institute of Human Nutrition Potsdam-Rehbruecke, D-14558 Nuthetal, Germany; German Center for Diabetes Research, D-85764 München-Neuherberg, Germany
| | - Wenke Jonas
- Department of Experimental Diabetology, German Institute of Human Nutrition Potsdam-Rehbruecke, D-14558 Nuthetal, Germany; German Center for Diabetes Research, D-85764 München-Neuherberg, Germany.
| | - Annette Schürmann
- Department of Experimental Diabetology, German Institute of Human Nutrition Potsdam-Rehbruecke, D-14558 Nuthetal, Germany; German Center for Diabetes Research, D-85764 München-Neuherberg, Germany; University of Potsdam, Institute of Nutritional Sciences, D-14558 Nuthetal, Germany.
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Thelen AM, Zoncu R. Emerging Roles for the Lysosome in Lipid Metabolism. Trends Cell Biol 2017; 27:833-850. [PMID: 28838620 DOI: 10.1016/j.tcb.2017.07.006] [Citation(s) in RCA: 160] [Impact Index Per Article: 22.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Revised: 07/28/2017] [Accepted: 07/31/2017] [Indexed: 12/20/2022]
Abstract
Precise regulation of lipid biosynthesis, transport, and storage is key to the homeostasis of cells and organisms. Cells rely on a sophisticated but poorly understood network of vesicular and nonvesicular transport mechanisms to ensure efficient delivery of lipids to target organelles. The lysosome stands at the crossroads of this network due to its ability to process and sort exogenous and endogenous lipids. The lipid-sorting function of the lysosome is intimately connected to its recently discovered role as a metabolic command-and-control center, which relays multiple nutrient cues to the master growth regulator, mechanistic target of rapamycin complex (mTORC)1 kinase. In turn, mTORC1 potently drives anabolic processes, including de novo lipid synthesis, while inhibiting lipid catabolism. Here, we describe the dual role of the lysosome in lipid transport and biogenesis, and we discuss how integration of these two processes may play important roles both in normal physiology and in disease.
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Affiliation(s)
- Ashley M Thelen
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA 94720, USA; The Paul F. Glenn Center for Aging Research at the University of California, Berkeley, Berkeley, CA 94720, USA
| | - Roberto Zoncu
- Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA 94720, USA; The Paul F. Glenn Center for Aging Research at the University of California, Berkeley, Berkeley, CA 94720, USA.
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Identification of eQTLs for hepatic Xbp1s and Socs3 gene expression in mice fed a high-fat, high-caloric diet. G3-GENES GENOMES GENETICS 2015; 5:487-96. [PMID: 25617409 PMCID: PMC4390565 DOI: 10.1534/g3.115.016626] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Nonalcoholic fatty liver disease (NAFLD) is a highly prevalent form of human hepatic disease and feeding mice a high-fat, high-caloric (HFHC) diet is a standard model of NAFLD. To better understand the genetic basis of NAFLD, we conducted an expression quantitative trait locus (eQTL) analysis of mice fed a HFHC diet. Two-hundred sixty-five (A/J × C57BL/6J) F2 male mice were fed a HFHC diet for 8 wk. eQTL analysis was utilized to identify genomic regions that regulate hepatic gene expression of Xbp1s and Socs3. We identified two overlapping loci for Xbp1s and Socs3 on Chr 1 (164.0–185.4 Mb and 174.4–190.5 Mb, respectively) and Chr 11 (41.1–73.1 Mb and 44.0–68.6 Mb, respectively), and an additional locus for Socs3 on Chr 12 (109.9–117.4 Mb). C57BL/6J-Chr 11A/J/ NaJ mice fed a HFHC diet manifested the A/J phenotype of increased Xbp1s and Socs3 gene expression (P < 0.05), whereas C57BL/6J-Chr 1A/J/ NaJ mice retained the C57BL/6J phenotype. In addition, we replicated the eQTLs on Chr 1 and Chr 12 (LOD scores ≥3.5) using mice from the BXD murine reference panel challenged with CCl4 to induce chronic liver injury and fibrosis. We have identified overlapping eQTLs for Xbp1 and Socs3 on Chr 1 and Chr 11, and consomic mice confirmed that replacing the C57BL/6J Chr 11 with the A/J Chr 11 resulted in an A/J phenotype for Xbp1 and Socs3 gene expression. Identification of the genes for these eQTLs will lead to a better understanding of the genetic factors responsible for NAFLD and potentially other hepatic diseases.
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Sapp V, Gaffney L, EauClaire SF, Matthews RP. Fructose leads to hepatic steatosis in zebrafish that is reversed by mechanistic target of rapamycin (mTOR) inhibition. Hepatology 2014; 60:1581-92. [PMID: 25043405 DOI: 10.1002/hep.27284] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Accepted: 06/27/2014] [Indexed: 12/14/2022]
Abstract
UNLABELLED Nonalcoholic fatty liver disease (NAFLD), the accumulation of lipid within hepatocytes, is increasing in prevalence. Increasing fructose consumption correlates with this increased prevalence, and rodent studies directly support fructose leading to NAFLD. The mechanisms of NAFLD and in particular fructose-induced lipid accumulation remain unclear, although there is evidence for a role for endoplasmic reticulum (ER) stress and oxidative stress. We have evidence that NAFLD models demonstrate activation of the target of rapamycin complex 1 (Torc1) pathway. We set out to assess the contribution of ER stress, oxidative stress, and Torc1 up-regulation in the development of steatohepatitis in fructose-treated larval zebrafish. Zebrafish were treated with fructose or glucose as a calorie-matched control. We also treated larvae with rapamycin, tunicamycin (ER stress), or valinomycin (oxidative stress). Fish were stained with oil red O to assess hepatic lipid accumulation, and we also performed quantitative polymerase chain reaction (qPCR)and western blot analysis. We performed immunostaining on samples from patients with NAFLD and nonalcoholic steatohepatitis (NASH). Treatment with fructose induced hepatic lipid accumulation, mitochondrial abnormalities, and ER defects. In addition, fructose-treated fish showed activation of inflammatory and lipogenic genes. Treatment with tunicamycin or valinomycin also induced hepatic lipid accumulation. Expression microarray studies of zebrafish NAFLD models showed an elevation of genes downstream of Torc1 signaling. Rapamycin treatment of fructose-treated fish prevented development of hepatic steatosis, as did treatment of tunicamycin- or valinomycin-treated fish. Examination of liver samples from patients with hepatic steatosis demonstrated activation of Torc1 signaling. CONCLUSION Fructose treatment of larval zebrafish induces hepatic lipid accumulation, inflammation, and oxidative stress. Our results indicate that Torc1 activation is required for hepatic lipid accumulation across models of NAFLD, and in patients.
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Affiliation(s)
- Valerie Sapp
- Division of Gastroenterology, Hepatology, and Nutrition, Children's Hospital of Philadelphia Research Institute, Philadelphia, PA
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Kebede MA, Attie AD. Insights into obesity and diabetes at the intersection of mouse and human genetics. Trends Endocrinol Metab 2014; 25:493-501. [PMID: 25034129 PMCID: PMC4177963 DOI: 10.1016/j.tem.2014.06.006] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2014] [Revised: 06/06/2014] [Accepted: 06/06/2014] [Indexed: 11/25/2022]
Abstract
Many of our insights into obesity and diabetes come from studies in mice carrying natural or induced mutations. In parallel, genome-wide association studies (GWAS) in humans have identified numerous genes that are causally associated with obesity and diabetes, but discovering the underlying mechanisms required in-depth studies in mice. We discuss the advantages of studying natural variation in mice and summarize several examples where the combination of human and mouse genetics opened windows into fundamental physiological pathways. A noteworthy example is the melanocortin-4 receptor (MC4R) and its role in energy balance. The pathway was delineated by discovering the gene responsible for the Agouti mutation in mice. With more targeted phenotyping, we predict that additional pathways relevant to human pathophysiology will be discovered.
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Affiliation(s)
- Melkam A Kebede
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Alan D Attie
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA.
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7
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Laggai S, Kessler SM, Boettcher S, Lebrun V, Gemperlein K, Lederer E, Leclercq IA, Mueller R, Hartmann RW, Haybaeck J, Kiemer AK. The IGF2 mRNA binding protein p62/IGF2BP2-2 induces fatty acid elongation as a critical feature of steatosis. J Lipid Res 2014; 55:1087-97. [PMID: 24755648 DOI: 10.1194/jlr.m045500] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Indexed: 12/12/2022] Open
Abstract
Liver-specific overexpression of the insulin-like growth factor 2 (IGF2) mRNA binding protein p62/IGF2BP2-2 induces a fatty liver, which highly expresses IGF2 Because IGF2 expression is elevated in patients with steatohepatitis, the aim of our study was to elucidate the role and interconnection of p62 and IGF2 in lipid metabolism. Expression of p62 and IGF2 highly correlated in human liver disease. p62 induced an elevated ratio of C18:C16 and increased fatty acid elongase 6 (ELOVL6) protein, the enzyme catalyzing the elongation of C16 to C18 fatty acids and promoting nonalcoholic steatohepatitis in mice and humans. The p62 overexpression induced the activation of the ELOVL6 transcriptional activator sterol regulatory element binding transcription factor 1 (SREBF1). Recombinant IGF2 induced the nuclear translocation of SREBF1 and a neutralizing IGF2 antibody reduced ELOVL6 and mature SREBF1 protein levels. Concordantly, p62 and IGF2 correlated with ELOVL6 in human livers. Decreased palmitoyl-CoA levels, as found in p62 transgenic livers, can explain the lipogenic action of ELOVL6. Accordingly, p62 represents an inducer of hepatic C18 fatty acid production via a SREBF1-dependent induction of ELOVL6. These findings underline the detrimental role of p62 in liver disease.
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Affiliation(s)
- Stephan Laggai
- Department of Pharmacy, Pharmaceutical Biology, Department of Pharmacy, Pharmaceutical, Saarland University, Saarbrücken, Germany
| | - Sonja M Kessler
- Department of Pharmacy, Pharmaceutical Biology, Department of Pharmacy, Pharmaceutical, Saarland University, Saarbrücken, Germany Medicinal Chemistry, Saarland University, Saarbrücken, Germany Laboratory of Hepato-gastroenterology, Institut de Recherche expérimentale et Clinique, Université catholique de Louvain, Brussels, Belgium
| | | | - Valérie Lebrun
- Laboratory of Hepato-gastroenterology, Institut de Recherche expérimentale et Clinique, Université catholique de Louvain, Brussels, Belgium
| | - Katja Gemperlein
- Department of Pharmacy, Pharmaceutical Biotechnology, Saarland University, Saarbrücken, Germany Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for Infection Research (HZI), Saarbrücken, Germany
| | - Eva Lederer
- Institute of Pathology, Medical University of Graz, Graz, Austria
| | - Isabelle A Leclercq
- Laboratory of Hepato-gastroenterology, Institut de Recherche expérimentale et Clinique, Université catholique de Louvain, Brussels, Belgium
| | - Rolf Mueller
- Department of Pharmacy, Pharmaceutical Biotechnology, Saarland University, Saarbrücken, Germany Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for Infection Research (HZI), Saarbrücken, Germany
| | - Rolf W Hartmann
- Medicinal Chemistry, Saarland University, Saarbrücken, Germany Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for Infection Research (HZI), Saarbrücken, Germany
| | | | - Alexandra K Kiemer
- Department of Pharmacy, Pharmaceutical Biology, Department of Pharmacy, Pharmaceutical, Saarland University, Saarbrücken, Germany
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The genetic basis of obesity-associated type 2 diabetes (diabesity) in polygenic mouse models. Mamm Genome 2014; 25:401-12. [PMID: 24752583 PMCID: PMC4164836 DOI: 10.1007/s00335-014-9514-2] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Accepted: 03/25/2014] [Indexed: 11/08/2022]
Abstract
Obesity-associated diabetes (“diabesity”) in mouse strains is characterized by severe insulin resistance, hyperglycaemia and progressive failure, and loss of beta cells. This condition is observed in inbred obese mouse strains such as the New Zealand Obese (NZO/HlLt and NZO/HlBomDife) or the TALLYHO/JngJ mouse. In lean strains such as C57BLKS/J, BTBR T+tf/J or DBA/2 J carrying diabetes susceptibility genes (“diabetes susceptible” background), it can be induced by introgression of the obesity-causing mutations Lep<ob> (ob) or Lepr<db> (db). Outcross populations of these models have been employed in the genome-wide search for mouse diabetes genes, and have led to positional cloning of the strong candidates Pctp, Tbc1d1, Zfp69, and Ifi202b (NZO-derived obesity) and Sorcs1,Lisch-like, Tomosyn-2, App, Tsc2, and Ube2l6 (obesity caused by the ob or db mutation). Some of these genes have been shown to play a role in the regulation of the human glucose or lipid metabolism. Thus, dissection of the genetic basis of obesity and diabetes in mouse models can identify regulatory mechanisms that are relevant for the human disease.
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Grimsrud PA, Carson JJ, Hebert AS, Hubler SL, Niemi NM, Bailey DJ, Jochem A, Stapleton DS, Keller MP, Westphall MS, Yandell BS, Attie AD, Coon JJ, Pagliarini DJ. A quantitative map of the liver mitochondrial phosphoproteome reveals posttranslational control of ketogenesis. Cell Metab 2012; 16:672-83. [PMID: 23140645 PMCID: PMC3506251 DOI: 10.1016/j.cmet.2012.10.004] [Citation(s) in RCA: 129] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2012] [Revised: 09/25/2012] [Accepted: 10/12/2012] [Indexed: 10/27/2022]
Abstract
Mitochondria are dynamic organelles that play a central role in a diverse array of metabolic processes. Elucidating mitochondrial adaptations to changing metabolic demands and the pathogenic alterations that underlie metabolic disorders represent principal challenges in cell biology. Here, we performed multiplexed quantitative mass spectrometry-based proteomics to chart the remodeling of the mouse liver mitochondrial proteome and phosphoproteome during both acute and chronic physiological transformations in more than 50 mice. Our analyses reveal that reversible phosphorylation is widespread in mitochondria, and is a key mechanism for regulating ketogenesis during the onset of obesity and type 2 diabetes. Specifically, we have demonstrated that phosphorylation of a conserved serine on Hmgcs2 (S456) significantly enhances its catalytic activity in response to increased ketogenic demand. Collectively, our work describes the plasticity of this organelle at high resolution and provides a framework for investigating the roles of proteome restructuring and reversible phosphorylation in mitochondrial adaptation.
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Affiliation(s)
- Paul A Grimsrud
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
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