Objective. MicroRNAs (miRNA) have recently emerged as a new class of modulators of gene expression. In this study we investigated the expression, regulation, and function of miR-155 and miR-146a in rheumatoid arthritis (RA) synovial fibroblasts (RASFs) and RA synovial tissue.Methods. Locked nucleic acid microarray was used to screen for differentially expressed miRNA in RASFs treated with tumor necrosis factor ␣ (TNF␣). TaqMan-based real-time polymerase chain reaction was applied to measure the levels of miR-155 and miR-146a. Enforced overexpression of miR-155 was used to investigate the function of miR-155 in RASFs.Results

Objective. To assess the expression of Toll-like receptor 3 (TLR-3) protein in synovial tissues and cultured synovial fibroblasts obtained from patients with rheumatoid arthritis (RA) and osteoarthritis (OA) and to investigate the consequences of stimulation of cultured synovial fibroblasts with TLR-3 ligands.Methods. TLR-3 expression in synovial tissues was determined by immunohistochemistry and immunofluorescence, and expression in cultured RA synovial fibroblasts (RASFs) was determined by fluorescenceactivated cell sorting and real-time polymerase chain reaction techniques. TLR-3 signaling was assessed by incubating RASFs with poly(I-C), lipopolysaccharide, palmitoyl-3-cysteine-serine-lysine-4, or necrotic synovial fluid cells from RA patients in the presence or absence of hydroxychloroquine or Benzonase. Subsequent determination of interferon-␤ (IFN␤), CXCL10, CCL5, and interleukin-6 (IL-6) protein production in the culture supernatants was performed by enzyme-linked immunosorbent assays.Results. TLR-3 protein expression was found to be higher in RA synovial tissues than in OA synovial tissues. TLR-3 expression was localized predominantly in the synovial lining, with a majority of the TLR-3-expressing cells coexpressing fibroblast markers.

Objective. To analyze the expression, regulation, and biologic relevance of Toll-like receptors (TLRs) 1-10 in synovial and skin fibroblasts and to determine the expression levels of TLRs 2, 3, and 4 in synovial tissues from patients with early rheumatoid arthritis (RA), longstanding RA, and osteoarthritis (OA).Methods. Expression of TLRs 1-10 in RA synovial fibroblasts (RASFs), OASFs, and skin fibroblasts was analyzed by real-time polymerase chain reaction (PCR).