Expression profile of circular RNA s in TMJ osteoarthritis synovial tissues and potential functions of hsa_circ_0000448 with specific back-spliced junction

Objective: As essential players in the occurrence and development of osteoarthritis, circular RNAs (circRNAs) have gradually received attention in recent years. However, their roles in temporomandibular joint osteoarthritis (TMJOA) featured with pain, restricted mouth opening and joint movement dysfunction, remains elusive. Methods: The expression profile of circRNAs in TMJ synovial tissues was analyzed by RNA-Seq. The differentially expressed circRNAs in the TMJOA were identified. The potential biological functions of these circRNAs were evaluated. Results: The expression profile of circRNAs in TMJ synovial tissues was stable and abundant, and most of which were newly discovered. A total of 58 differentially expressed circRNAs were identified in TMJOA, and four of which were identified by in vitro experiments. Among them, the up-regulated hsa_circ_0000448 with specific back-splice junction was involved in the TNF-α signaling pathway through CeRNA mechanism by targeting related microRNAs. Additionally, it was also predicted to bind several RNA binding proteins (RBPs), but almost had no protein-coding ability. Conclusion: circRNAs in TMJ synovial tissue participate in the progression of TMJOA and may become a potential therapeutic target. The highly up-regulated has_circ_0000448 probably promotes TNF-α secretion of synovium through CeRNA mechanism in TMJOA.