TRIM3 exacerbates chondrocyte apoptosis through suppression of AKT/mTOR signaling pathway in osteoarthritis

Introduction: Osteoarthritis (OA), a prevalent cause of global disability, is characterized by progressive articular cartilage degeneration. Despite its clinical significance, the molecular pathogenesis remains incompletely understood, posing challenges for developing disease-modifying therapies.Methods: Utilizing knee OA datasets from GEO database, we systematically evaluated TRIM3 expression patterns during disease progression. Comparative analyses of TRIM3 protein levels between OA and normal cartilage were performed using Western blot and immunohistochemistry (IHC). In TRIM3-knockdown (siTRIM3) chondrocytes, we employed qRT-PCR and Western blotting to quantify Bcl-2/Bax expression ratios and assess AKT/mTOR pathway activation through phosphorylation status (p-AKT/p-mTOR). To establish functional dependency, siTRIM3 cells were treated with mTOR inhibitor followed by reevaluation of Bcl-2/Bax balance. Apoptotic responses to IL-1β stimulation were quantified by flow cytometry, while collagen II (COL2A1) preservation was visualized via immunofluorescence.Results: Integrated bioinformatics and IHC analyses demonstrated significant TRIM3 upregulation in OA cartilage compared to healthy controls (p < 0.01). TRIM3 depletion exerted dual protective effects: (1) modulating apoptotic regulators by decreasing Bax while increasing Bcl-2 expression, and (2) enhancing AKT/mTOR pathway activation evidenced by elevated p-AKT/p-mTOR levels.Notably, mTOR inhibition abolished these effects, restoring pro-apoptotic Bax expression and suppressing anti-apoptotic Bcl-2 (p < 0.05), confirming pathway mediation. Functionally, siTRIM3 conferred 40% reduction in IL-1β-induced apoptosis (p < 0.05) and remarkably preserved COL2A1 integrity, exhibiting 2.3-fold higher fluorescence intensity versus controls (p < 0.01).Conclusion: Our findings establish TRIM3 as a novel regulator of OA pathogenesis that exacerbates disease progression through AKT/mTOR pathway suppression, thereby promoting chondrocyte apoptosis and extracellular matrix degradation. Therapeutic targeting of TRIM3 may represent a promising strategy to attenuate cartilage degeneration in OA.