Abstract
INTRODUCTION: As a leading cause of disability worldwide, osteoarthritis (OA) progressively degrades articular cartilage. The incomplete understanding of OA's molecular mechanisms hinders development of disease-modifying treatments. METHODS: We analyzed GEO database knee OA datasets to track TRIM3 expression dynamics throughout disease progression. Western blot and IHC quantified TRIM3 protein differences between OA and normal cartilage. TRIM3-knockdown chondrocytes showed altered Bcl-2/Bax ratios via qRT-PCR/Western blot, with p-AKT/p-mTOR levels indicating AKT/mTOR activation. 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 = 0.043). 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 < 0.01), confirming pathway mediation. Functionally, siTRIM3 conferred 40% reduction in IL-1β-induced apoptosis (P = 0.0081) and remarkably preserved COL2A1 integrity, exhibiting 2.3-fold higher fluorescence intensity versus controls. 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.