miR-129-3p alleviates chondrocyte apoptosis in knee joint fracture-induced osteoarthritis through CPEB1

Background: Osteoarthritis (OA), a refractory disease, is one of the leading contributors for disability worldwide. Since chondrocyte is the only resident cell in cartilage, this study aims to explore the roles of miR-129-3p and CPEB1 in chondrocyte apoptosis in knee joint fracture-induced OA. Methods: Cartilage was collected from 20 OA patients who underwent total knee replacement (OA group) and 20 patients with knee contusion (normal group). Then, miR-129-3p and CPEB1 levels in the cartilage were quantified by qRT-PCR. Primary rat chondrocytes in the knee were isolated and identified by toluidine blue staining and immunofluorescent staining of type II collagen. OA cellular models were induced by TNF-alpha treatment, in which miR-129-3p and CPEB1 expressions were assessed. Subsequently, cell viability, apoptosis, and the expression levels of apoptotic protein and caspase-3 were measured. Dual luciferase reporter assay identified the interaction between miR-129-3p and CPEB1. Results: Patients in the OA group had decreased miR-129-3p expression and increased CPEB1 expression than those in the normal group. TNF-alpha treatment successfully induced the OA cellular model. Downregulated miR-129-3p and upregulated CPEB1 expressions were found in OA-treated chondrocytes. miR-129-3p overexpression or CPEB1 knockdown improved chondrocyte viability and attenuated apoptosis, and vice versa. miR-129-3p negatively regulated CPEB1, thus ameliorating apoptosis and enhancing cell viability. Conclusion: miR-129-3p negatively targeted CPEB1 to facilitate chondrocyte viability and hamper apoptosis.