SGLT2/SGK1介导Th17/Tregs失衡在糖尿病肾病进展中的分子机制研究

The pathogenesis of diabetic nephropathy (DN) is unclear. It is currently thought that the imbalance of Th17 / Tregs is the key mechanism. Our previous studies have found that the proportion of Th17 / Tregs increased in peripheral blood and kidney of DN mice. There were increases in the mice renal SGLT2, SGK1 protein expression in DN. Further isolation of Th17 cells from kidney tissue of DN mice revealed an increase in SGK1 expression. Therefore, we hypothesize that SGLT2 is activated by high glucose in diabetic patients and promotes the reabsorption of glucose and Na+ in the renal tubules, leading to high Na+ in the local microenviroment, inducing SGK1/ Foxo1/RORγt in T cells of renal tissues, thereby promoting Th17 differentiation and Th17 / Tregs upregulation, resulting in the occurrence and development of DN; while SGLT2 inhibitor and SGK1 inhibitor can alleviate the process. This project intends to use crispr / cas9 and other means to further study the molecular mechanism of SGLT2/SGK1 induced Th17 differentiation and DN progression in cell and animal models. Through this study, it will provide new targets for the clinical treatment of DN patients, which has important theoretical value and clinical significance.

糖尿病肾病（DN）的发病机制尚不清楚。目前认为Th17/Tregs失衡是其重要机制之一。课题组前期发现，Th17/Tregs比例在DN小鼠外周血和肾组织中均显著上升，DN小鼠肾组织中SGLT2、SGK1表达增加，分离DN小鼠肾组织中Th17细胞，发现SGK1表达亦增加，而SGLT-2i能减少肾脏SGK1表达。故提出假说：在糖尿病患者中，高糖条件应激激活SGLT2，促进葡萄糖和Na+在肾小管的重吸收，导致肾脏局部高Na+，激活肾组织T细胞中SGK1/Foxo1/RORγt通路，介导Th17/Tregs失衡，导致DN进展，而SGLT2或SGK1抑制剂干预可缓解该过程。本项目拟在细胞和动物模型中利用crispr/cas9等技术手段深入研究SGLT2/SGK1在高糖、高盐刺激下诱导Th17分化及DN进展的分子机制。通过本项目的研究，将为DN患者的临床治疗提供新的靶点，具有重要的理论价值和临床意义。

糖尿病肾病(Diabetic nephropathy, DN)是2型糖尿病的主要并发症。辅助性T细胞(Th17)和调节性T细胞(Treg)之间的失衡是DN发病的重要机制。血清/糖皮质激素调节激酶1 (SGK1)是一种丝氨酸-苏氨酸激酶，对稳定Th17细胞表型至关重要。钠-葡萄糖共转运蛋白2 (SGLT2)是一种葡萄糖转运蛋白，已被确定为糖尿病的治疗靶点。我们的研究探讨了SGLT2在DN发生发展中的调控作用。结果表明，敲除SGLT2可抑制高糖诱导的小鼠肾小管上皮细胞TCMK-1过度分泌Na+和炎症因子。高Na+诱导小鼠原代CD4+ T细胞Th17分化，上调SGK1、磷酸化叉头盒蛋白O1 (p-FoxO1)和白介素23受体(IL-23R)。CD4+ T细胞与SGLT2表达不足的TCMK-1细胞共培养可显著抑制细胞迁移能力，降低促炎细胞因子水平，并通过下调SGK1、p-FoxO1和IL-23R抑制Th17分化。体内研究数据也显示，SGLT2敲低显著下调了db/db小鼠的SGK1。SGLT2或SGK1表达不足也可改善Th17/Treg失衡，抑制DN的发展，并调节p-FoxO1和IL-23R的表达。综上所述，本研究表明，SGLT2的下调可以通过改变局部环境中Na+含量，调节SGK1/p-FoxO1/ IL-23R轴，从而恢复Th17/Treg平衡，抑制DN。这些发现强调了SGLT2和SGK1在DN中的治疗潜力。