miR-125b/Sp1对糖尿病皮肤MMP-9表达的调控作用及其机制研究

Our previous study has demonstrated that advanced glycation end products（AGEs） play important roles in the development of diabetic skin tissues by upregulating MMP-9 promoter activity and inducing MMP-9 gene expression of keratinocytes.Further promoter activity analysis showed that the active region of MMP-9 gene promoter contained nulcear factor Sp1 binding site,and AGEs promoted MMP-9 promoter activity through regulating its SP1 binding site. However, the exact mechanism remains unknown. It has also been reported that microRNAs play critical roles in the process of diabetic skin. We found that miR-125b was down-regulated after the treatment of AGEs, being accompanied with the increase of MMP-9 promoter activity.Further bioinformatical analysis showes that Sp1 maybe the potential target of miR-125b.Based on these information and results, we speculate that AGEs regulate SP1 expression via influencing miR-125b, and the increase of Sp1 expression activates MMP-9 gene promoter activity and leads to the high expression of MMP-9 . In the present study,we aim to investigate the regulation of SP1 on MMP-9 gene promoter activity ,and also prove the effect of miR-125b stimulated by AGEs in the process.This research may help to discover the new mechanism of high MMP-9 expression in diabetic skin, and represent potential targets for the therapy of diabetic skin to improve diabetic wound healing.

我们已经证明糖基化终末产物(AGEs)通过上调MMP-9基因启动子活性，促进MMP-9高表达，从而参与糖尿病皮肤病变发生；进一步研究证实AGEs影响MMP-9启动子区域的Sp1 结合位点介导启动子活性改变。但是，AGEs如何发挥对Sp1的调控作用，目前仍不清楚。已知miRNA在糖尿病皮肤病变中发挥重要作用，我们发现AGEs增强MMP-9启动子活性的同时，也触发了miR-125b的表达下调，而生物信息学分析显示miR-125b的靶基因中包含Sp1。因此，我们提出AGEs通过miR-125b影响Sp1介导的MMP-9启动子活性改变这一新机制。本项目拟进一步采用EMSA、siRNA、启动子活性分析等方法，旨在获得miR-125b调控Sp1参与AGEs促糖尿病皮肤MMP-9高表达的可靠证据。本项目有望揭示糖尿病皮肤病变MMP-9高表达的调控机制，为糖尿病皮肤病变治疗确立新的靶点提供更充分的科学依据

糖尿病皮肤病变是糖尿病的一种常见慢性并发症，但其发病机制至今仍不清楚。我们已经证明糖基化终末产物(AGEs)通过上调MMP-9基因启动子活性，促进MMP-9高表达，从而参与糖尿病皮肤病变发生；进一步研究证实AGEs影响MMP-9启动子区域的Sp1 结合位点介 导启动子活性改变。但是，AGEs如何发挥对Sp1的调控作用，目前仍不清楚。已知miRNA 在糖尿病皮肤病变中发挥重要作用，我们发现AGEs增强MMP-9启动子活性的同时，也触发了miR-129和-335的表达下调，而生物信息学分析显示Sp1为miR-129 和-335的共同的靶基因，miRNA129/335 通过协同作用靶向调节转录因子 SP1，降低 MMP-9 启动子活性，抑制 MMP-9 蛋白的表达；伤口局部注射miRNA129/335 可以促进糖尿病大鼠皮肤伤口的愈合。本项目研究揭示了糖尿病皮肤病变 MMP-9 高表达的调控机制，为糖尿病皮肤病变治疗确立新的靶点提供了一定的科学依据。