title: Simvastatin inhibits cysteine-rich protein 61 expression in rheumatoid arthritis synovial fibroblasts through the regulation of sirtuin-1/FoxO3a signaling.
abstract: OBJECTIVE
  To examine the role of sirtuin-1 (SIRT-1)/FoxO3a in the expression of cysteine-rich protein 61 (CYR-61) in rheumatoid arthritis synovial fibroblasts (RASFs) and the influence of simvastatin on this pathway, and to determine the relationship between disease progression and FoxO3a/CYR-61 signaling in synovial fibroblasts in vivo using a rat model of collagen-induced arthritis (CIA).
  
  
  METHODS
  In RASFs, the expression of CYR-61 and SIRT-1, the localization of FoxO3a in the nucleus/cytoplasm, and the phosphorylation/acetylation of FoxO3a were examined by Western blotting. Secretion of CCL20 was assessed by enzyme-linked immunosorbent assay. Promoter activity of the Cyr61 gene was evaluated by luciferase assay, with or without forced expression of FoxO3a and SIRT-1 by lentiviral transduction. FoxO3a-Cyr61 promoter interaction was examined by chromatin immunoprecipitation. In rats with CIA, the expression of CYR-61 and phosphorylated FoxO3a in synovial fibroblasts was examined by immunohistochemistry.
  
  
  RESULTS
  In RASFs, simvastatin suppressed the tumor necrosis factor α (TNFα)-induced production of CYR-61 and CCL20. Nuclear levels of FoxO3a were decreased after TNFα stimulation of RASFs, and forced expression of FoxO3a reversed the inductive effects of TNFα on CYR-61. Simvastatin inhibited the nuclear export, phosphorylation, and acetylation of FoxO3a and maintained its binding to the Cyr61 promoter. Forced expression of SIRT-1 in RASFs led to decreased levels of CYR-61 and deacetylation of FoxO3a. Following treatment with simvastatin, the expression of SIRT-1 was up-regulated and SIRT-1/FoxO3a binding was enhanced in RASFs. In rats with CIA, intraarticular injection of simvastatin alleviated arthritis and suppressed CYR-61 expression and FoxO3a phosphorylation in synovial fibroblasts.
  
  
  CONCLUSIONS
  CYR-61 is important in the pathogenesis of RA, and SIRT-1/FoxO3a signaling is crucial to induction of CYR-61 in RASFs. Simvastatin plays a beneficial role in inflammatory arthritis through its up-regulation of SIRT-1/FoxO3a signaling in synovial fibroblasts. Continued study of the pathways linking sirtuins, FoxO proteins, and the inflammatory responses of RASFs may provide new insights into the pathophysiology of RA.
authors.affiliation: National Taiwan University and National Taiwan University Hospital, Taipei, Taiwan.
authors.forename: Sang-Heng
authors.initials: SH
authors.lastname: Kok
authors.forename: Li-Deh
authors.initials: LD
authors.lastname: Lin
authors.forename: Kuo-Liang
authors.initials: KL
authors.lastname: Hou
authors.forename: Chi-Yuan
authors.initials: CY
authors.lastname: Hong
authors.forename: Cheng-Chi
authors.initials: CC
authors.lastname: Chang
authors.forename: Michael
authors.initials: M
authors.lastname: Hsiao
authors.forename: Jyh-Horng
authors.initials: JH
authors.lastname: Wang
authors.forename: Eddie Hsiang-Hua
authors.initials: EH
authors.lastname: Lai
authors.forename: Sze-Kwan
authors.initials: SK
authors.lastname: Lin
mesh_terms: D000818:Animals; D001169:Arthritis, Experimental / Q000188:drug therapy / Q000378:metabolism; D001172:Arthritis, Rheumatoid / Q000188:drug therapy / Q000378:metabolism*; D002478:Cells, Cultured; D054418:Chemokine CCL20 / Q000378:metabolism; D055515:Cysteine-Rich Protein 61 / Q000235:genetics / Q000378:metabolism*; D004195:Disease Models, Animal; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D000071316:Forkhead Box Protein O3; D051858:Forkhead Transcription Factors / Q000378:metabolism*; D006801:Humans; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000494:pharmacology; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction / Q000187:drug effects / Q000276:immunology; D019821:Simvastatin / Q000494:pharmacology*; D056564:Sirtuin 1 / Q000378:metabolism*; D013583:Synovial Membrane / Q000166:cytology / Q000276:immunology; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
chemical_list: C108355:CCL20 protein, human; C501848:CCN1 protein, human; C501849:CCN1 protein, rat; C486997:Ccl20 protein, rat; D054418:Chemokine CCL20; D055515:Cysteine-Rich Protein 61; C499517:FOXO3 protein, human; C499515:FOXO3 protein, rat; D000071316:Forkhead Box Protein O3; D051858:Forkhead Transcription Factors; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors; D014409:Tumor Necrosis Factor-alpha; D019821:Simvastatin; C447939:SIRT1 protein, human; C488368:Sirt1 protein, rat; D056564:Sirtuin 1