The Function And Mechanism Of MiRNA-137 Regulating REG3A To Inhibit Keratinocyte Proliferation

Impaired migration and proliferation of keratinocytes is one of the reasons that lead to impaired wound healing in diabetic patients.REG3A/Reg?? regulates the proliferation of keratinocytes to promote wound healing in normal skin wounds,while the expression of REG3A in diabetic skin wounds is significantly reduced,thereby inhibiting the healing of diabetic skin wounds.Although miRNAs(microRNAs)have been shown to silence gene expression via targeting mRNA 3'UTR(3' untranslated regions),it is unclear whether the reduction of REG3A in diabetic skin wounds would be associated with miRNAs.In this study,we first analyzed the possible miRNAs targeting REG3A mRNA 3'UTR by TargetScan,miRanda,DIANA-microT,and found that miR137 could bind to human REG3A mRNA 3'UTR and mouse Reg?? mRNA 3'UTR,respectively.The luciferase assay confirmed that miR-137 inhibited the expression of REG3A and Reg??.Subsequently,we found that miR137 was involved in the regulation of IL-33-induced REG3A,thereby inhibiting the proliferation of keratinocytes by cell scratch assay.Furthermore,we found that the expression of miR137 was significantly increased in diabetic skin wounds,and high glucose was able to induce miR137 in a time-dependent manner in keratinocytes.These data suggest that increased expression of miR137 induced by high glucose in diabetic skin wounds may result in low expression of REG3A.To identify the possible transcription factors involved in the regulation of miR-137,we used PROMO and Jaspar databeses to find p5 3 as a potential transcript factor of miR-137 promoter,and confirmed that p53 regulated the transcript activity of miR-137 promoter by Luciferase reporter assay.Moreover,we found that p53 agonist Tevilion-1 restored the expression of miR137 that was inhibited by IL-33 or increased miR-137 induced by high glucose,both of which inhibited the expression of RGE3A.Besides p53,the expression miR137 regulated by IL-33 was partially dependent on DNA methylations.As the methyltransferase inhibitor restored the expression of miR-137 that was inhibited by IL-33.In summary,our study demonstrates that IL-33 inhibits miR137 to induce the expression of REG3A,or high glucose induces miR-137 to inhibit the expression of REG3A.However,in diabetic skin wounds,decreased IL-33 and increased level of glucose induces miR137,both of which result in low expression of REG3A,thereby inhibiting the proliferation of keratinocytes.Moreover,p53,as a transcription factor of miR137,is involved in miR137 expression that was regulated by IL-33 and high glucose.In conclusion,our findings reveal that IL-33 and high glucose regulate miR137 to affect the expression of REG3A in keratinocytes,and provide a potential new target for the treatment of diabetic skin wounds.