Experimental cell research
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The role of apoptosis in the pathogenesis of intervertebral disc degeneration (IDD) remains enigmatic. Accumulating evidence has shown that the apoptotic machinery is regulated by miRNAs. The aim of this study was to evaluate the effect of miR-138-5p on apoptosis in human NP cells induced by TNF-α and to explore the mechanism of this process. ⋯ Together, these results indicate that miR-138-5p is a novel regulator of human NP cell apoptosis induced by TNF-α. The knockout of miR-138-5p expression protected human NP cells from apoptosis via the upregulation of SIRT1, which was possibly mediated via PTEN/PI3K/Akt signaling. These findings suggest that the miR-138-5p/SIRT1/PTEN/PI3K/Akt signaling pathway might represent a novel therapeutic target for the prevention of IDD.
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Hypertrophic scar (HS) is a fibroproliferative disorder caused by abnormal wound healing, which is characterized by excessive deposition of extracellular matrix (ECM) secreted by fibroblasts. We previous have found that expression of microRNA-21(miR-21) was increased in tissues and fibroblasts of HS. However, the underlying molecular mechanism remains to be further elucidated. ⋯ Furthermore, we also found that miR-21 promoted TGF-β1 induced fibroproliferative expression by repressing Smad7 expression in vitro. In addition, the miR-21 inhibitor inhibited the growth of hypertrophic scar tissue in vivo (nude mice experimental model). These results indicated that miR-21 was a critical regulator for HS formation and TGF- β1/miR-21/Smad7 pathway could be a useful therapeutic target for the treatment of HS.