title: The transcription cofactor CRTC1 protects from aberrant hepatic lipid accumulation.
abstract: Nonalcoholic fatty liver disease (NAFLD) is a rapidly emerging global health-problem. NAFLD encompasses a range of conditions associated with hepatic steatosis, aberrant accumulation of fat in hepatocytes. Although obesity and metabolic syndrome are considered to have a strong association with NAFLD, genetic factors that predispose liver to NAFLD and molecular mechanisms by which excess hepatic lipid develops remain largely unknown. We report that the transcription cofactor CRTC1 confers broad spectrum protection against hepatic steatosis development. CRTC1 directly interferes with the expression of genes regulated by lipogenic transcription factors, most prominently liver x receptor α (LXRα). Accordingly, Crtc1 deficient mice develop spontaneous hepatic steatosis in young age. As a cyclic AMP effector, CRTC1 mediates anti-steatotic effects of calorie restriction (CR). Notably, CRTC1 also mediates anti-lipogenic effects of bile acid signaling, whereas it is negatively regulated by miR-34a, a pathogenic microRNA upregulated in a broad spectrum of NAFLD. These patterns of gene function and regulation of CRTC1 are distinct from other CR-responsive proteins, highlighting critical protective roles that CRTC1 selectively plays against NAFLD development, which in turn provides novel opportunities for selectively targeting beneficial therapeutic effects of CR.
authors.affiliation: Center for Computational and Integrative Biology, Massachusetts General Hospital, Boston MA 02114, USA.|Department of Genetics, Harvard Medical School, Boston MA 02115, USA.
authors.forename: Hwijin
authors.initials: H
authors.lastname: Kim
mesh_terms: D000818:Animals; D001647:Bile Acids and Salts / Q000378:metabolism; D002784:Cholesterol / Q000378:metabolism; D000242:Cyclic AMP / Q000378:metabolism; D059305:Diet, High-Fat / Q000009:adverse effects; D005786:Gene Expression Regulation; D056945:Hep G2 Cells; D006801:Humans; D050356:Lipid Metabolism / Q000502:physiology*; D050155:Lipogenesis / Q000502:physiology; D008099:Liver / Q000378:metabolism*; D000071518:Liver X Receptors / Q000378:metabolism; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D035683:MicroRNAs / Q000235:genetics; D065626:Non-alcoholic Fatty Liver Disease / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D001647:Bile Acids and Salts; C500984:CRTC1 protein, human; C519509:Crtc1 protein, mouse; D000071518:Liver X Receptors; C551848:MIRN34a microRNA, mouse; D035683:MicroRNAs; C000605213:NR1H3 protein, human; D014157:Transcription Factors; D002784:Cholesterol; D000242:Cyclic AMP