Upregulation of miR-98 Inhibits Apoptosis in Cartilage Cells in Osteoarthritis

Gui-Long Wang  ¹ , Yu-Bo Wu  ¹ , Jia-Tian Liu  ¹ , Cui-Yun Li  ²

Affiliations

• ¹ 1 Department of Orthopedics, Linyi People’s Hospital , Linyi, P.R. China .
• ² 2 Department of Pathology, Linyi People’s Hospital , Linyi, P.R. China .

Abstract

Objective: We aimed to investigate the effects of microRNA-98 (miR-98) on apoptosis in cartilage cells of osteoarthritis (OA) patients.

Methods: Knee cartilage tissue samples were collected from 31 OA patients, 21 autopsies, and 26 amputation patients due to trauma. The clinicopathological data were recorded. Quantitative real-time polymerase chain reaction was performed to compare the miR-98 expression levels from cartilage cells obtained from the OA and non-OA patients. Clinicopathological characteristics of the patients were also analyzed. Primary chondrocytes were separated from cartilage tissues and transfected with plasmids or siRNA to overexpress or inhibit miR-98. Annexin V-PI double staining and TUNEL assays were used to examine apoptosis in the primary chondrocytes after transfection. Finally, a rat OA model was used to confirm the effects of miR-98 on apoptosis in cartilage cells in vivo.

Results: Compared with the normal cartilage tissues, miR-98 expression was reduced in the OA cartilage tissues (p < 0.01). The miR-98 expression levels were also significantly correlated with the OA stage (p < 0.05). In vitro, transfection with the miR-98 inhibitor increased apoptosis in the cartilage cells (p < 0.05), and transfection with a miR-98 mimic inhibited apoptosis in cartilage cells (p < 0.05). In the OA rat model, exogenous injection of the miR-98 mimic inhibited apoptosis in the rat cartilage cells thus alleviating OA.

Conclusion: MiR-98 expression is reduced in the cartilage cells of OA patients and the overexpression of miR-98 inhibits cartilage cell apoptosis, while inhibition of microRNA-98 leads to cartilage cell apoptosis. These findings provide a theoretical basis for the development of novel targeted therapies for OA.

Keywords: Annexin V-PI double staining assay; TUNEL assay; apoptosis; cartilage cells; miR-98; osteoarthritis; siRNA.