TRIM15 drives chondrocyte senescence and osteoarthritis progression

Osteoarthritis (OA) is a prevalent joint disease characterized by pain, disability, and loss of physical function, posing a challenge to public health. However, molecular mechanisms of OA pathogenesis have not been fully described. We report that tripartite motif containing 15 (TRIM15) is a regulator in chondrocyte senescence and OA. Our study revealed heightened expression of TRIM15 in chondrocytes of senescent cartilage from patients with OA and in aged wild-type mice. Using gain- and loss-of-function studies, we found that TRIM15 facilitated human chondrocyte senescence. Conditional deletion of <i>Trim15</i> in mouse chondrocytes severely impaired skeletal growth, partially because of impaired embryonic chondrocyte senescence. Compared with conditionally knocked out <i>Col2a1-CreER^T2/Trim15^flox/flox</i> mice, <i>Trim15</i>^flox/flox control mice exhibited accelerated OA phenotypes, increased senescence markers, and senescence-associated secretory phenotype during aging. Mechanistically, TRIM15 bound with yes-associated protein (YAP) and mediated K48-linked YAP ubiquitination at K254, which interrupted the interaction between YAP and angiomotin, leading to enhanced YAP nuclear translocation. Dysregulation of TRIM15-YAP and transcriptional coactivator with PDZ-binding motif (TAZ) signaling promoted OA progression in both the surgery-induced and natural aging-induced mouse OA model. Intra-articular injection of adeno-associated virus 5 (AAV5)-<i>Trim15</i> shRNA decelerated OA progression in mice. In particular, YAP and TAZ protein amounts were increased in chondrocytes of patients with OA. Our preclinical results demonstrated that the AAV5-<i>TRIM15</i> shRNA treatment protected human OA explants against degeneration through inhibiting chondrocyte senescence. Together, our findings underscore the potential of targeting TRIM15 in reshaping the aging cartilage microenvironment and suggest a promising therapeutic avenue for OA.