Emerging role of circular RNA in intervertebral disc degeneration: Knowns and unknowns

Lower back pain (LBP) is one of the predominant factors contributing to dyskinesia and remains a serious social and economic burden worldwide. Intervertebral disc degeneration (IDD) is the leading cause of LBP; the existing IDD treatments cannot completely prevent IDD. Circular RNAs (circRNAs) are non-coding RNAs resulting from back-splicing with unique structural characteristics and functions. Accumulating evidence suggests that circRNAs are involved in the pathological process of IDD and modulate a range of IDD-related genes or proteins. However, the underlying circRNA-mediated regulatory mechanisms remain poorly understood. The aim of the present review is to describe the current understanding of circRNA characteristics, classification, biogenesis and function in relation to its specific roles in IDD. Additionally, the limitations on the current knowledge in the field and the future direction of IDD-related research are also discussed.