Targeting of CDKN1B by miR-222-3p may contribute to the development of intervertebral disc degeneration.

MicroRNAs (miRNAs) are small endogenous non-coding RNAs that can negatively regulate the expression of their complementary mRNA targets, and have been implicated in various pathophysiological processes. In this study, we examined the effect of miR-222-3p on intervertebral disc degeneration (IDD). We found that expression of miR-222-3p was significantly higher in IDD tissues than in normal intervertebral disc tissue, and report that overexpression of miR-222-3p remarkably increased apoptosis and reduced proliferation of nucleus pulposus (NP) cells. In addition, miR-222-3p promoted secretion of matrix metalloproteinase-3, and decreased collagen type II and aggrecan production. Cyclin-dependent kinase inhibitor 1B (CDKN1B) was identified as a direct target of negative regulation by miR-222-3p in NP cells, and expression of miR-222-3p was found to be negatively correlated with that of CDKN1B in IDD tissue. Finally, we observed that transfection with miR-222-3p dramatically reduced CDKN1B expression in NP cells. In conclusion, miR-222-3p may be involved in IDD development, possibly through targeting CDKN1B.