NF-kappa Bp65-specific siRNA inhibits expression of genes of COX-2, NOS-2 and MMP-9 in rat IL-1 beta-induced and TNF-alpha-induced chondrocytes

Objective: Small interfering RNA (siRNA) triggers RNA interference in mammalian somatic cells. Nuclear factor kappa B (NF-kappa B) is a transcription factor that is implicated in inflammation and immune activation. This study was to use NF-kappa Bp65-specific siRNA to inhibit the expression of genes of cyclooxygenase-2 (COX-2), nitric oxide synthase-2 (NOS-2) and matrix metalloproteinase-9 (MMP-9), which is paralleled with the initiation and progression of cartilage lesions in osteoarthritis (OA) model, in induced chondrocytes, and therefore to explore a new gene therapy for OA. Methods: Western blot and reverse transcriptase polymerase chain reaction (RT-PCR) were performed to optimize the silencing effects of NF-kappa Bp65-specific siRNA in cultured rat chondrocytes, and then to determine the expression of COX-2, NOS-2 and MMP-9 in induced chondrocytes. The activation of NF-kappa B was determined by electrophoretic mobility shift assay (EMSA). Western blot and RT-PCR were subjected to densitometric analysis and then band intensities were also determined. Results: The NF-kappa Bp65-specific siRNA inhibited the expression of NF-kappa Bp65 and activation of NF-kappa B, reducing significantly the expression of COX-2, NOS-2 and MMP-9 induced by interleukin-1 beta (IL-1 beta) and tumor necrosis factor-alpha (TNF-alpha) in cultured chondrocytes. Conclusions: NF-kappa Bp65-specific siRNA can inhibit the expression of COX-2, NOS-2 and MMP-9 in IL-1 beta-induced and TNF-alpha-induced chondrocytes. This suggests that NF-kappa Bp65-specific siRNA has potential to be a useful, preventive and therapeutic agent for OA at early stages. (c) 2005 OsteoArthritis Research Society International. Published by Elsevier Ltd. All rights reserved.OrthopedicsRheumatologySCI(E)PubMed58ARTICLE4367-3761