甲基转移酶(Dnmts)参与肿瘤发生及细胞衰老，但其在足细胞中的生物学作用不清楚。我们前期研究发现：①DN患者肾小球足细胞Dnmt1高表达；②高糖上调体外足细胞Dnmt1表达；③沉默Dnmt1降低基因组整体甲基化水平，并上调nephrin和podocin蛋白表达。提示Dnmt1介导的甲基化可能参与DN足细胞损伤，但Dnmt1的调控机制尚不清楚。我们新近发现：抑制核转录因子Sp1、p65可降低高糖诱导的Dnmt1高表达。由此推测：p65/Sp1可能介导Dnmt1高表达，导致DN足细胞nephrin和podocin低表达引起足细胞损伤。本研究拟通过体外转染和干扰Dnmt1及足细胞条件性Dnmt1基因敲除和敲入糖尿病小鼠，探索其对nephrin和podocin表达影响；通过IP、ChIP技术，获得p65/Sp1直接调控Dnmt1的证据。项目有望揭示DN足细胞损伤修复的新机制，为其防治提供新靶点。

Methyltransferase (Dnmts) was involved in tumorigenesis and cell aging, however, its biological role in podocytes is unclear.Our preliminary results found that: ① the protein expression of Dnmt1 was increased in podocyte of DN patients; ② high glucose increased the protein expression of Dnmt1 in vitro; ③ Dnmt1 silencing reduced overall genomic methylation level and increased the protein expression of nephrin and podocin. These results indicated that Dnmt1 mediated methylation may be involved in podocyte injury of DN, however, the regulation mechanism of Dnmt1 mediated podocyte injury need to be further elucidated. We recently observed that inhibition expression and activity of Sp1 and p65 decreased HG induced Dnmt1 protein expression. Therefore, we proposed that p65/Sp1 might mediate Dnmt1 expression and involved in podocyte injury pf DN. Dnmt1 transfection and interference in vitro and podocyte Dnmt1 conditional knockout and knockin diabetic mice were used for exploring its impact on the expression of nephrin and podocin; direct target relationship between p65/Sp1 and Dnmt1 was identified by IP and ChIP technology. This study is expected to reveal a new mechanism of podocyte injury and repair in DN, and provide new targets and scientific basis for prevention.