Circ_0066881 targets miR-144-5p/RORA axis to alleviate LPS-induced apoptotic and inflammatory damages in human periodontal ligament cells.

Circular RNAs (circRNAs) are involved in the regulation of various diseases, including periodontitis. The objective of this study was to analyze the biological role and regulatory mechanism of circ_0066881 in LPS-induced periodontal ligament cells (PDLCs). Circ_0066881, microRNA-144-5p (miR-144-5p) and retinoid acid-related orphan receptor A (RORA) levels were determined using reverse transcription-quantitative PCR (RT-qPCR) assay. Cell viability detection was performed by Cell Counting Kit-8 assay. Cell apoptosis was assessed through flow cytometry and caspase-3 activity assay. The protein analysis was completed via Western blot. Inflammatory cytokines were measured by ELISA. The target interaction was validated by dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay. The level of circ_0066881 was down-regulated in periodontitis tissues. Overexpression of circ_0066881 relieved LPS-induced cell viability inhibition and apoptosis or inflammation promotion in PDLCs. Circ_0066881 could bind to miR-144-5p. The protective function of circ_0066881 was achieved by sponging miR-144-5p in PDLCs. Circ_0066881 acts as a miR-144-5p sponge to mediate the RORA level. Inhibition of miR-144-5p attenuated LPS-induced cell injury via targeting RORA. All these results demonstrated that circ_0066881 partly prevented LPS-evoked cell dysfunction in PDLCs through miR-144-5p-mediated up-regulation of RORA.