MicroRNAs: New players in intervertebral disc degeneration.

Chronic low back pain is generally attributed to intervertebral disc (IVD) degeneration (IDD), which is closely associated with apoptosis, extracellular matrix (ECM) disruption, cell proliferation and inflammatory response. Currently, there is no clinical therapy targeting the pathophysiology of disc degeneration. microRNAs (miRNAs) are a class of small noncoding RNA molecules that negatively regulate gene expression at the post-transcriptional levels. miRNAs not only regulate many normal physiological processes, but also play an important role in the development of most disorders, including degenerative disc disease. A variety of miRNAs are differentially expressed in degenerative human IVD tissues and cells. Among these, some of the miRNAs have been shown to be involved in multiple pathological processes during disc degeneration, including apoptosis, ECM degradation, cell proliferation and inflammatory response. This review will mainly focus on the expression profiles, roles, and therapeutic implications of miRNAs in IDD. With continued efforts, restoration of dysregulated miRNA expression may represent a promising biological treatment approach for mitigating or reversing IVD degeneration.