title: The orphan nuclear receptor Rev-erb alpha regulates circadian expression of plasminogen activator inhibitor type 1.
abstract: Plasminogen activator inhibitor type 1 (PAI-1) is a major physiologic regulator of the fibrinolytic system and has recently gained recognition as a modulator of inflammation and atherosclerosis. PAI-1 exhibits circadian rhythmicity in its expression, peaking in the early morning, which is associated with increased risk for cardiovascular events. However, the mechanisms that determine PAI-1 circadian rhythmicity remain poorly understood. We discovered that the orphan nuclear receptor Rev-erb alpha, a core component of the circadian loop, represses human PAI-1 gene expression through two Rev-erb alpha binding sites in the PAI-1 promoter. Mutations of these sites, as well as RNA interference targeting endogenous Rev-erb alpha and its corepressors, led to increased expression of the PAI-1 gene. Furthermore, glycogen synthase kinase 3beta (GSK3beta) contributes to pai-1 repression by phosphorylating and stabilizing Rev-erb alpha protein, which can be blocked by lithium. Interestingly, serum shock generated circadian oscillations in PAI-1 mRNA in NIH3T3 cells, suggesting that PAI-1 is a direct output gene of the circadian loop. Ectopic expression of a stabilized form of Rev-erb alpha that mimics GSK3beta phosphorylation dramatically dampened PAI-1 circadian oscillations. Thus, our results suggest that Rev-erb alpha is a major determinant of the circadian PAI-1 expression and a potential modulator of the morning susceptibility to myocardial infarction.
authors.affiliation: Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia 19104, USA.
authors.forename: Jing
authors.initials: J
authors.lastname: Wang
authors.forename: Lei
authors.initials: L
authors.lastname: Yin
authors.forename: Mitchell A
authors.initials: MA
authors.lastname: Lazar
mesh_terms: D000818:Animals; D001665:Binding Sites; D006528:Carcinoma, Hepatocellular / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D002478:Cells, Cultured; D047369:Chromatin Immunoprecipitation; D002940:Circadian Rhythm / Q000502:physiology*; D004268:DNA-Binding Proteins / Q000502:physiology*; D005786:Gene Expression Regulation; D038362:Glycogen Synthase Kinase 3 / Q000378:metabolism; D000071679:Glycogen Synthase Kinase 3 beta; D006801:Humans; D015151:Immunoblotting; D007668:Kidney / Q000166:cytology / Q000378:metabolism; D008113:Liver Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D051379:Mice; D041681:NIH 3T3 Cells; D056953:Nuclear Receptor Subfamily 1, Group D, Member 1; D010766:Phosphorylation; D017395:Plasminogen Activator Inhibitor 1 / Q000235:genetics* / Q000378:metabolism; D011401:Promoter Regions, Genetic; D034622:RNA Interference; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D018160:Receptors, Cytoplasmic and Nuclear / Q000502:physiology*; D012045:Regulatory Sequences, Nucleic Acid; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015842:Serine Proteinase Inhibitors / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic
chemical_list: D004268:DNA-Binding Proteins; C064353:NR1D1 protein, human; C498262:Nr1d1 protein, mouse; D056953:Nuclear Receptor Subfamily 1, Group D, Member 1; D017395:Plasminogen Activator Inhibitor 1; D012333:RNA, Messenger; D018160:Receptors, Cytoplasmic and Nuclear; D015842:Serine Proteinase Inhibitors; C000605506:GSK3B protein, human; D000071679:Glycogen Synthase Kinase 3 beta; C000605507:Gsk3b protein, mouse; D038362:Glycogen Synthase Kinase 3