CKB overexpression mitigates osteoarthritis by delaying chondrocyte senescence via activation of the RAP1/PI3K/AKT signaling pathway.

BACKGROUND

Osteoarthritis (OA) is an age-related degenerative joint disease characterized by alterations in cellular senescence phenotypes. Although the pathogenesis of OA remains incompletely understood, chondrocyte senescence is considered a key driver in the OA pathological process. Therefore, this study aimed to identify pivotal senescence-related genes during OA and investigate their potential value as therapeutic targets.

METHODS

The hub gene CKB for OA was identified by analyzing OA-related sequencing datasets (GSE169077 and GSE42295) from the GEO database in conjunction with a senescence-associated gene set. Western blotting, immunohistochemistry, and immunofluorescence were subsequently employed to detect CKB expression levels in human and rat OA tissues. An IL-1β-induced senescence model in rat primary chondrocytes was established, and a lentiviral vector overexpressing CKB was constructed to validate its functional role. Subsequently, combined analysis of CKB co-expression genes and OA-related gene sets was performed to screen and identify the downstream RAP1/PI3K/AKT signaling pathway. Rescue experiments further confirmed the effect of CKB on the RAP1/PI3K/AKT pathway and the associated changes in senescence-related phenotypes. Finally, a rat knee joint OA model was used to evaluate the therapeutic effect of CKB overexpression.

RESULTS

CKB expression was decreased in OA tissues. In vitro experiments demonstrated that CKB overexpression suppressed IL-1β-induced chondrocyte senescence. Further mechanistic investigation revealed that CKB overexpression upregulates RAP1 expression, thereby activating the PI3K/AKT signaling pathway to delay chondrocyte senescence. In vivo experiments showed that CKB overexpression delayed the progression of OA in rat knee joints.

CONCLUSION

The findings of this study indicate that CKB, as a potential therapeutic target for OA, activates the RAP1/PI3K/AKT signaling pathway to delay chondrocyte senescence, thereby ameliorating OA progression.