富集miR-130b的脂肪间质干细胞外泌体通过mTOR信号调控自噬水平改善糖尿病肾脏损伤的机制研究

High glucose induced mTOR activation is critical in the pathogenesis of diabetic renal injury, ultimately leading to glomerular hypertrophy and renal fibrosis. It has been demonstrated that mTOR inhibition caused by rapamycin can restore the autophagy inhibited by high glucose and attenuate high glucose induced glomerular mesangial cell damage. Previous research has found that the levels of serum.microRNA-130b (miR-130b) decreased in type 2 diabetes patients, and it was negatively correlated with urinary albumin excretion rate and levels of serum kidney damage related factors such as fibronectin and TNF-α. Our recent study found that miR-130b can inhibit the expression of mTOR. MiR-130b derived-from adipocyte can be taken up by recipient muscle tissue to regulate its metabolism through inhibiting PGC-1α expression. Thus, in this project we'll firstly mimic a co-culture system by using culture medium of adipocytes and mesangial cells, to explore the effects and mechanism of exosome miR-130b against high glucose-induced deregulation of autophagy in mouse mesangial cells. Then we will explore Exosomes from miR-130b-overexpressing brown adipose-derived stem cell (ADSC) as a novel strategy to improve the outcome of diabetic nephropathy.

高血糖诱导的mTOR信号激活是导致糖尿病肾脏损伤的重要机制，并最终导致肾小球肥大、肾脏纤维化。研究已证明，应用雷帕霉素抑制mTOR信号，可恢复高糖抑制的大鼠肾小球系膜细胞系膜自噬功能，改善高糖诱导的肾小球系膜细胞损伤。前期研究发现2型糖尿病患者血循环miR-130b表达水平明显下降，且循环miR-130b表达水平与尿白蛋白排泄率和血清纤连蛋白、TNFα等肾损伤相关因子含量呈显著负相关。预实验结果表明，miR-130b下调小鼠肾小球系膜细胞mTOR基因表达。脂肪细胞来源的miR-130b可被肌肉组织细胞摄取，通过抑制PGC-1α信号调节其代谢功能。本项目将模拟脂肪细胞和肾小球系膜细胞共培养体系，阐述脂肪细胞来源的外泌体miR-130b作为信号分子，参与调节高糖培养的肾小球系膜细胞自噬功能的机制，继而探讨开发棕色脂肪间质干细胞外泌体为载体的miR-130b传送系统作为糖尿病肾病新疗法的可行性。

高血糖诱导的mTOR信号激活是导致糖尿病肾脏损伤的重要机制，并最终导致肾小球肥大、肾脏纤维化。研究已证实，应用雷帕霉素抑制mTOR信号，可恢复高糖抑制的大鼠肾小球系膜细胞系膜自噬功能，改善高糖诱导的肾小球系膜细胞损伤。前期研究发现2型糖尿病患者血循环miR-130b表达水平明显下降，且循环miR-130b表达水平与尿白蛋白排泄率和血清纤连蛋白、TNFα等肾损伤相关因子含量呈显著负相关。前期开展研究发现miR-130b可调节小鼠肾小球系膜细胞mTOR信号通路，可能对糖尿病肾脏损伤发挥保护作用。本研究首次证实，脂肪间质干细胞来源的外泌体miR-130b可被肾小球系膜细胞摄取，并可靶向调控肾小球系膜细胞Wnt2B，进而调节其下游的关键信号分子mTOR 信号通路，改善高血糖诱导的肾小球系膜细胞自噬功能紊乱、细胞外基质蛋白的积聚、细胞凋亡，进而改善高血糖导致的肾小球细胞细胞功能。本研究利用原代脂肪间质干细胞，制备大量富集 miR-130b的外泌体，为外泌体负载的miR-130b递送系统用于治疗糖尿病肾病提供了理论依据和实验基础。