circTMEM230 Sponges miR-223-3p to Promote Endplate Chondrocyte Extracellular Matrix Synthesis and Attenuate Tension-Induced Disc Degeneration.

Circular RNAs (circRNAs) are important regulators of signaling pathways involved in intervertebral disc degeneration (IVDD). This study investigated the role and underlying mechanism of circTMEM230 in the degeneration of endplate chondrocytes. We observed that circTMEM230 expression was significantly downregulated in chondrocytes subjected to intermittent cyclic mechanical tension (ICMT). Functional assays demonstrated that overexpression of circTMEM230 enhanced the expression of extracellular matrix (ECM)-related genes through modulation of the miR-223-3p/FOXO3/SOX9 signaling axis. Specifically, circTMEM230 acted as a molecular sponge for miR-223-3p, thereby upregulating FOXO3, which subsequently promoted SOX9 transcription. In vivo experiments further confirmed that circTMEM230 mitigated IVDD progression and regulated the expression of miR-223-3p, FOXO3, and SOX9. Additionally, expression levels of circTMEM230, miR-223-3p, FOXO3, and SOX9 were found to be correlated in endplate cartilage tissue samples from IVDD patients. These findings suggest that circTMEM230 exerts a protective role in IVDD and may serve as a promising therapeutic target for further investigation.