Adenovirus-Mediated Small Interfering RNA Targeting TAK1 Ameliorates Joint Inflammation with Collagen-Induced Arthritis in Mice.

Transforming growth factor β-activated kinase-1 (TAK1) is a key upstream kinase in cell signaling during inflammation, which regulates the expression of inflammatory mediators. Small interfering RNA (siRNA) against TAK1 offers promise as a potential therapeutic strategy in immune-mediated inflammatory disorder including rheumatoid arthritis. Here, we are to evaluate the therapeutic effects of intra-articular administration of adenoviral-mediated siRNA against TAK1 (ad-siRNA-TAK1) on collagen-induced arthritis (CIA) in mice. Ad-siRNA-TAK1 was constructed. The murine RAW 264.7 macrophages were infected with ad-siRNA-TAK1, and the silencing specificity of TAK1 was assessed by quantitative polymerase chain reaction (PCR) and western blot. DBA/1 mice were injected intra-articularly with ad-siRNA-TAK1. Development and severity of arthritis was assessed histologically. Synovial inflammation and bone destruction were determined by hematoxylin and eosin (HE) staining. Articular and serum concentrations of tumor necrosis factor-α, interleukin-1, and interleukin-6 were determined using enzyme-linked immunosorbent assay. Levels of phosphorylated p38, c-Jun N-terminal kinase (JNK), and extracellular-signal-regulated kinase (ERK) were detected by western blot. In vitro, ad--siRNA-TAK1 efficiently inhibited the expression of TAK1 at both mRNA and protein levels. In vivo, intra-articular injection of ad-siRNA-TAK1 efficiently alleviated joint inflammation, decreased the expression of pro-inflammatory mediators, and suppressed JNK pathways. Our results demonstrate the efficiency of ad--siRNA-TAK1 in controlling joint inflammation of CIA, which is associated with the suppression of the expression of pro-inflammatory cytokines and JNK activation.