TLR4-IN-C34 attenuates the progression of osteoarthritis through inhibiting inflammation, angiogenesis and pain

Osteoarthritis (OA), a common degenerative articular disease, is symbolized as joint pain and functional impairment. Chronic inflammation, oxidative stress, and chondrocyte apoptosis are characteristics of the OA pathogenesis. Single-cell RNA sequencing (scRNA-seq) and immunofluorescence of human cartilage demonstrated that the Toll-like receptors 4 (TLR4) expression was increased in OA patients and the function of TLR4 was activated. As specific TLR4 inhibitor, we demonstrated in vitro and in vivo that C34 inhibited the catabolism of chondrocytes and promoted anabolism. C34 restrained pain response, alleviated the lameness, and suppressed expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in mice after destabilized medial meniscus (DMM) surgery. Additionally, C34 restrained angiogenesis associated with OA. Mechanistically, C34 was attributed to suppressing the NF-κB signaling pathways. Our results showed that C34 had anti-OA effects both in vitro and in vivo. These results suggest that targeting TLR4 offered promising therapeutic potential for OA.