高血糖介导BMI1基因异常活化诱导DNA CpG岛去甲基化促进糖尿病肾病的作用和机制研究

糖尿病肾病是严重的糖尿病并发症，与DNA去甲基化相关，机制不明。我们前期研究发现糖尿病患者随血糖升高DNA CpG岛去甲基化，BMI1基因表达增高。甲基化芯片和RNA seq分析见随着Bmi1升高出现ESRRG基因的cg20845835去甲基化以致ESRRG基因表达增加、DNMT1基因下调、DNA CpG岛去甲基化。预实验见HK-2细胞Bmi-1表达与葡萄糖浓度呈正相关，细胞增殖加剧。沉默Bmi1基因或加用二甲双胍后高糖加速增殖的现象能被逆转，CpG岛甲基化比例上升。Bmi1+/-糖尿病小鼠模型见肾损害较野生型糖尿病鼠要轻。本项目拟通过干扰Bmi1表达、DNA甲基化芯片及RNA seq检测等技术，结合细胞学和动物学研究，以及临床肾穿病理和患者随访资料，从基因表达调控及细胞功能的角度，验证高血糖上调Bmi-1表达后如何通过诱导DNA CpG去甲基化促发糖尿病肾病，及二甲双胍的肾脏保护机制。

Diabetic nephropathy is a severe diabetic complication, related to DNA demethylation. The mechanism is unclear. Our previous study found that DNA CpG islands were demethylated with increased blood glucose and upregulation of BMI1 gene expression in diabetic patients. Methylation and RNA seq analysis showed that the ESRRG cg20845835 demethylation appeared with increased Bmi1, resulting in increased ESRRG expression， down-regulation DNMT1 gene and demethylation of DNA CpG island. Pre-experiment showed that up-regulation of BMI1 in HK-2 cells with high glucose concentration and cell proliferation increased. Silencing the Bmi1 gene or adding metformin can inhibit proliferation by high glucose. And the methylation proportion of CpG island increased. The kidney injury in the Bmi1+/- mouse diabetic model was less than that of the wild-type diabetic mouse. This project intends to interfere with BMI1 expression, DNA methylation and RNA seq detection by cytology and zoology research, as well as analysis of clinical renal biopsy pathology and patient follow-up data, to verify the upregulation of Bmi-1 by high glucose and induce diabetic kidney injury by inducing DNA CpG demethylation with downstream genes expression regulation and changes of kidney cells, as well as the renal protection of metformin.