Aucubin inhibits IL-1-or TNF--induced extracellular matrix degradation in nucleus pulposus cellthrough blocking the miR-140-5p/CREB1 axis

In intervertebral disc degeneration (IDD), increased proinflammatory molecules secreted by human nucleus pulposus cells (HNPCs) could promote the expression of extracellular matrix (ECM)-degrading enzymes. IDD could be affected by both genetic and environmental factors, including microRNAs (miRNAs). Aucubin, the active ingredient of a traditional Chinese medicine herb Du Zhong, has been reported to promote osteogenic differentiation; however, the role of aucubin in IDD and the underlying mechanism remain unclear. Herein, we evaluated the effect of aucubin on TNF-- or IL-1-induced ECM degradation in HNPCs. By using online tools, miR-140 was selected as a candidate miRNA that is related to TNF- or IL-1 signaling. Overexpression of miR-140 enhanced the effect of aucubin on ECM degradation. Moreover, cAMP responsive element binding protein 1 (CREB1), a major transcriptional factor in immune-related signaling, was a direct downstream target of miR-140. CREB1 knockdown mimicked the function of miR-140 overexpression on ECM degradation. In summary, aucubin might ameliorate IL-1- or TNF--induced ECM degradation in HNPCs through regulating miR-140/CREB1.