TAK-242 (Resatorvid) inhibits proinflammatory cytokine production through the inhibition of NF-κB signaling pathway in fibroblast-like synoviocytes in osteoarthritis patients

Fibroblast-like synoviocytes (FLSs) are involved in osteoarthritis (OA) pathogenesis through pro-inflammatory cytokine production. TAK-242, a TLR4 blocker, has been found to have a significant impact on the gene expression profile of pro-inflammatory cytokines such as IL1-β, IL-6, TNF-α, and TLR4, as well as the phosphorylation of Ikβα, a regulator of the NF-κB signaling pathway, in OA-FLSs. This study aims to investigate this effect because TLR4 plays a crucial role in inflammatory responses. Ten OA patients' synovial tissues were acquired, and isolated FLSs were cultured in DMEM in order to assess the effectiveness of TAK-242. The treated FLSs with TAK-242 and Lipopolysaccharides (LPS) were analyzed for the mRNA expression level of IL1-β, IL-6, TNF-α, and TLR4 levels by Real-Time PCR. Besides, we used western blot to assess the protein levels of Ikβα and pIkβα. The results represented that TAK-242 effectively suppressed the gene expression of inflammatory cytokines IL1-β, IL-6, TNF-α, and TLR4 which were overexpressed upon LPS treatment. Additionally, TAK-242 inhibited the phosphorylation of Ikβα which was increased by LPS treatment. According to our results, TAK-242 shows promising inhibitory effects on TLR4-mediated inflammatory responses in OA-FLSs by targeting the NF-κB pathway. TLR4 inhibitors, such as TAK-242, may be useful therapeutic agents to reduce inflammation and its associated complications in OA patients, since traditional and biological treatments may not be adequate for all of them.