title: Regulation and function of SIRT1 in rheumatoid arthritis synovial fibroblasts.
abstract: Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by inflammation and destruction of synovial joints. The function of sirtuin (SIRT)1 in RA is inconclusive. In human synovial cells, SIRT1 was shown to promote cytokine production and apoptosis resistance. However, deletion of SIRT1 aggravated inflammatory arthritis in mice and increased production of pro-inflammatory cytokines in murine macrophages. In the current study, we investigated the regulation, expression, and function of SIRT1 in RA, in particular its role in adhesion and proliferation of human RA synovial fibroblasts (RASF). We found that expression of SIRT1 was increased in vivo in synovial tissues of RA smokers and in vitro by stimulation of RASF with TNFα, but decreased upon treatment with cigarette smoke extract. Synovial tissues of RA smokers showed higher leukocytic infiltration that positively correlated with enhanced levels of SIRT1. Global transcriptome analysis revealed that SIRT1 modulates expression of genes involved in the regulation of inflammatory response and cell adhesion. In functional studies, silencing of SIRT1 reduced proliferation and leukocytic adhesion to RASF but showed inconsistent results in the regulation of adhesion to plastic. In conclusion, SIRT1 modulates the proliferative and potentially also adhesive properties of RASF and can therefore promote progression of RA.
  
  
  CONCLUSIONS
  SIRT1 is upregulated by TNFα but decreased upon CSE treatment of RASF. Upregulation of SIRT1 in RA smokers correlates with increased leukocytic infiltration. SIRT1 modulates expression of genes regulating cell adhesion and inflammation. SIRT1 regulates proliferation of RASF.
authors: Center of Experimental Rheumatology, Bio-Technopark Schlieren, University Hospital Zurich, Gloriastrasse 25, 8091 Zurich and Wagistrasse 14, 8952, Schlieren, Switzerland.|Zurich Center of Integrative Human Physiology (ZIHP), University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland.
authors: Anna
authors: A
authors: Engler
authors: Center of Experimental Rheumatology, Bio-Technopark Schlieren, University Hospital Zurich, Gloriastrasse 25, 8091 Zurich and Wagistrasse 14, 8952, Schlieren, Switzerland.
authors: Clare
authors: C
authors: Tange
authors: Center of Experimental Rheumatology, Bio-Technopark Schlieren, University Hospital Zurich, Gloriastrasse 25, 8091 Zurich and Wagistrasse 14, 8952, Schlieren, Switzerland.
authors: Mojca
authors: M
authors: Frank-Bertoncelj
authors: Center of Experimental Rheumatology, Bio-Technopark Schlieren, University Hospital Zurich, Gloriastrasse 25, 8091 Zurich and Wagistrasse 14, 8952, Schlieren, Switzerland.
authors: Renate E
authors: RE
authors: Gay
authors: Center of Experimental Rheumatology, Bio-Technopark Schlieren, University Hospital Zurich, Gloriastrasse 25, 8091 Zurich and Wagistrasse 14, 8952, Schlieren, Switzerland.
authors: Steffen
authors: S
authors: Gay
authors: Center of Experimental Rheumatology, Bio-Technopark Schlieren, University Hospital Zurich, Gloriastrasse 25, 8091 Zurich and Wagistrasse 14, 8952, Schlieren, Switzerland. caroline.ospelt@usz.ch.
authors: Caroline
authors: C
authors: Ospelt
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000893:Anti-Inflammatory Agents / Q000494:pharmacology / Q000627:therapeutic use; D001172:Arthritis, Rheumatoid / Q000188:drug therapy / Q000235:genetics* / Q000378:metabolism* / Q000473:pathology; D002448:Cell Adhesion / Q000235:genetics; D049109:Cell Proliferation; D005260:Female; D005347:Fibroblasts / Q000378:metabolism*; D005786:Gene Expression Regulation; D020868:Gene Silencing; D006801:Humans; D008297:Male; D008875:Middle Aged; D056564:Sirtuin 1 / Q000235:genetics* / Q000378:metabolism*; D013583:Synovial Membrane / Q000166:cytology* / Q000378:metabolism*
chemical_list: D000893:Anti-Inflammatory Agents; D056564:Sirtuin 1
keywords: Adhesion; Proliferation; Rheumatoid arthritis; SIRT1; Smoking