Cellular communication network factor 3 contributes to the pathological process of rheumatoid arthritis through promoting cell senescence and osteoclastogenesis in the joint.

Rheumatoid arthritis (RA) is a chronic systemic and autoimmune disease that primarily affects joints and causes pain, stiffness and swelling. The affected joints exhibit severe inflammation in the synovium and bone erosion, leading to joint deformity. Aging is an important factor facilitating the development of RA, as it is associated with an increase in the number of senescent cells and the production of the autoantibodies and proinflammatory cytokines in tissues. Given that CCN3 is highly expressed in RA joints and that its level is associated with the severity of the disease, we explored its molecular function in joints and therapeutic potential in RA. An analysis of public scRNA-seq data from the RA synovium revealed that CCN3 is expressed by an inflammatory fibroblast subset. Interestingly, stimulation with CCN3 resulted in the activation of the senescence pathway in synoviocytes and osteoclast differentiation in monocytes in vitro. Consistent with these results, the administration of CCN3 into the knee joint and onto the calvarial bone resulted in increased numbers of senescent synoviocytes in the joint and osteoclasts in the bone, respectively. Furthermore, the therapeutic potential of targeting CCN3 was evaluated in an experimental RA model. Administration of the CCN3 antibody significantly suppressed inflammation and osteoclast numbers in the joints of the RA model mice. Our findings suggest that CCN3 contributes to pathological processes in RA and represents a promising therapeutic target for the treatment of RA.