CircATRNL1 protects against osteoarthritis by targeting miR-153-3p and KLF5

Background: Osteoarthritis (OA) is characterized by chondrocyte injury. Circular RNAs (circRNAs) are involved in the pathogenesis of various diseases, including OA. The purpose of this study was to determine the potential role of circATRNL1 in OA pathology in vitro. Methods: Human chondrocytes were isolated and treated with interleukin-1 beta (IL-1 beta) to mimic OA in vitro. High-throughput RNA sequencing was performed to identify differentially expressed circRNAs, miRNAs and mRNAs between IL and 1 beta-treated chondrocytes and normal chondrocytes. The expression of circATRNL1, miR-153-3p and KLF5 was measured using quantitative real-time polymerase chain reaction (qRT-PCR). For functional analyses, cell apoptosis was assessed using a flow cytometry assay. Extracellular matrix (ECM) degradation was monitored by measuring the levels of ECM-associated proteins by Western blot. The potential target miRNAs of circATRNL1 were screened by bioinformatics analysis and verified by dual-luciferase reporter assay. Results: The expression of circATRNL1 was decreased in IL-1 beta-treated chondrocytes. CircATRNL1 overexpression ameliorated cell apoptosis and ECM degradation, which were promoted by IL-1 beta treatment. Mechanistic analysis revealed that circATRNL1 directly targeted miR-153-3p and that miR-153-3p could reverse the inhibitory effects of circATRNL1 overexpression on inflammatory responses, cell apoptosis and ECM degradation. KLF5 is a target of miR-153-3p. Conclusion: Taken together, the results in this study suggested that circATRNL1 might ameliorate the development and progression of OA through regulating miR-153-3p/KLF5 axis. Our study increased the understanding of circRNAs as therapeutic targets in the treatment of OA.

Automated summary

In this study, it was found that circATRNL1 is downregulated in IL-1 beta-treated chondrocytes, and its overexpression can improve cell apoptosis and ECM degradation. CircATRNL1 directly targets miR-153-3p, and miR-153-3p can reverse the inhibitory effects of circATRNL1 overexpression on inflammatory responses, cell apoptosis, and ECM degradation. KLF5 is a target of miR-153-3p.