Hck promotes IL-1β-induced extracellular matrix degradation, inflammation, and apoptosis in osteoarthritis via activation of the JAK-STAT3 signaling pathway.

We investigated role of haematopoietic cell kinase (Hck) in osteoarthritis (OA) and to explore the underlying mechanisms driving its effects. An OA animal model was established and after OA induction, rats received intra-articular injections of lentivirus twice a week for four weeks. Rats were divided into four groups: control (healthy rats without OA), OA model (rats with induced OA), OA + Len-si-NC (OA rats treated with a non-targeting control lentivirus), and OA + Len-si-Hck (OA rats treated with lentivirus targeting Hck). Blood samples were collected, and serum cytokine levels were measured using ELISA. Afterward, the rats were sacrificed for histological analysis and TUNEL assay. In vitro, IL-1β-treated human chondrocytes were transfected with Hck, and the effects on cell viability, apoptosis, ECM degradation, and JAK-STAT3 signaling were assessed. Colivelin, a JAK-STAT3 agonist, was used to confirm the pathway's involvement. Results indicated increased Hck expression in the cartilage tissues of OA rats and in IL-1β-stimulated chondrocytes. Silencing Hck in vivo reduced IL-6 and TNF-α levels, apoptosis, and preserved cartilage structure. In vitro, Hck knockdown in IL-1β-treated chondrocytes resulted in enhanced cell viability, reduced apoptosis, and decreased ECM degradation. Notably, the expression of MMP3 and MMP13 was significantly lowered, while collagen II and aggrecan levels were restored. Additionally, Hck knockdown inhibited JAK-STAT3 activation, which was evident from reduced levels of phosphorylated JAK1 and STAT3. The addition of colivelin reversed these effects, confirming that Hck mediates its effects through the JAK-STAT3 pathway. Overall, our findings indicate that Hck is critical in OA progression by promoting inflammation, apoptosis, and ECM degradation through the JAK-STAT3 signaling pathway activation.