Changjian Chen1, Peng Yin2, Shengxiong Hu3, Xuegang Sun4, Baowen Li5. 1. Joint Surgical Department, The Second Hospital of Dalian Medical University, China. 2. Orthopedic Trauma Department, The Second Hospital of Dalian Medical University, China. 3. Orthopedic Surgery, People's Hospital of Huangyuan County, Qinghai Province, China. 4. Orthopedic Surgery, The Second Hospital of Dalian Medical University, China. Electronic address: sunxxxgang@163.com. 5. Joint Surgical Department, The Second Hospital of Dalian Medical University, China. Electronic address: Libaowen127@163.com.
Abstract
AIMS: Osteoarthritis (OA) is a common degenerative joint disease characterized by cartilage degeneration and joint inflammation. As its pathogenesis remains unclear, there are no effective treatments established. Circular RNA (circRNA), microRNA (miRNA), and other noncoding RNAs participate in OA development; however, the effects and mechanisms of circRNA and miRNA in OA remain unknown. MAIN METHODS: Cartilage miRNA was examined in patients with and without OA. KEY FINDINGS: CircRNA-9119 and phosphatase and tensin homolog (PTEN) expression decreased in OA-affected cartilage and interleukin (IL)-1β-induced chondrocytes, and miR-26a expression significantly decreased in normal cells and tissues. CircRNA-9119 overexpression restored chondrocyte growth, whereas IL-1β treatment impaired chondrocyte growth. Annexin V-FITC & PI flow cytometry and Bcl-2/Bax ratio measurement indicated that the apoptosis of IL-1β-treated articular chondrocytes was decreased by circRNA-9119 upregulation. Bioinformatic prediction and the dual-luciferase reporter assay indicated that circRNA-9119 served as a miR-26a sponge and that miR-26a targeted the 3'-UTR of PTEN. Transfection of chondrocytes with a circRNA-9119-overexpressing vector revealed downregulation of miR-26a expression. Furthermore, circRNA-9119 overexpression induced PTEN expression. In addition, a miR-26a mimic induced IL-1β-induced chondrocyte apoptosis, and circRNA-9119 overexpression inhibited IL-1β-induced chondrocyte apoptosis. SIGNIFICANCE: CircRNA-9119 is an important regulator of IL-1β-treated chondrocytes through the miR-26a/PTEN axis, possibly contributing to OA development.
AIMS: Osteoarthritis (OA) is a common degenerative joint disease characterized by cartilage degeneration and joint inflammation. As its pathogenesis remains unclear, there are no effective treatments established. Circular RNA (circRNA), microRNA (miRNA), and other noncoding RNAs participate in OA development; however, the effects and mechanisms of circRNA and miRNA in OA remain unknown. MAIN METHODS: Cartilage miRNA was examined in patients with and without OA. KEY FINDINGS: CircRNA-9119 and phosphatase and tensin homolog (PTEN) expression decreased in OA-affected cartilage and interleukin (IL)-1β-induced chondrocytes, and miR-26a expression significantly decreased in normal cells and tissues. CircRNA-9119 overexpression restored chondrocyte growth, whereas IL-1β treatment impaired chondrocyte growth. Annexin V-FITC & PI flow cytometry and Bcl-2/Bax ratio measurement indicated that the apoptosis of IL-1β-treated articular chondrocytes was decreased by circRNA-9119 upregulation. Bioinformatic prediction and the dual-luciferase reporter assay indicated that circRNA-9119 served as a miR-26a sponge and that miR-26a targeted the 3'-UTR of PTEN. Transfection of chondrocytes with a circRNA-9119-overexpressing vector revealed downregulation of miR-26a expression. Furthermore, circRNA-9119 overexpression induced PTEN expression. In addition, a miR-26a mimic induced IL-1β-induced chondrocyte apoptosis, and circRNA-9119 overexpression inhibited IL-1β-induced chondrocyte apoptosis. SIGNIFICANCE: CircRNA-9119 is an important regulator of IL-1β-treated chondrocytes through the miR-26a/PTEN axis, possibly contributing to OA development.