糖酵解与氨基酸代谢供能方式的切换在糖尿病肾病早期足细胞损伤中的作用及意义

肾小球足细胞表达丰富的葡萄糖和氨基酸转运受体，提示葡萄糖和氨基酸代谢与足细胞功能密切相关。系统生物学研究发现糖尿病状态下糖酵解紊乱，前期研究发现氨基酸可作为葡萄糖替代底物为足细胞供能。本项目拟研究糖尿病状态下足细胞糖酵解与氨基酸分解代谢能量转换机制，假设氨基酸分解代谢产物通过下游信号干扰足细胞功能。本课题用不同种糖尿病动物模型和糖尿病肾病组织明确糖酵解与氨基酸代谢切换的关系。在原代足细胞和足细胞系中，评估慢性高糖对足细胞糖酵解能力的影响和可能的能量转换途径。敲除足细胞糖酵解关键酶（PKM2），用能量代谢仪和同位素追踪的方法明确葡萄糖和氨基酸的代谢特点，确证足细胞在糖酵解障碍环境下氨基酸代偿供能的能量代谢特点。氨基酸是mTOR的敏感底物，观察抑制mTOR信号是否通过纠正足细胞能量代谢紊乱减轻糖尿病肾病足细胞损伤。从能量代谢的角度明确糖尿病肾病早期足细胞损伤机制，探索糖尿病肾病治疗的新靶点。

The expression of glucose transporters and amino acid transporters are enriched in glomerular podocytes which implies that glucose and amino acid metabolism contributes to energy supply of podocytes. Accumulating evidence of systematic biology have indicated that glycolysis disorder is present in diabetic cases with complications, and preliminary data suggested that amino acids could act as a substitute substrate to supply energy in absence of glucose in podocyte. The present project intends to explore the metabolic reprogramming from glycolysis to amino acid catabolism in podocyte under conditions of diabetic nephropathy and proposes that metabolites of amino acid catabolism could promote activity of mTOR signaling to interfere with podocyte homeostasis. In this study, the switching between glycolysis and amino acid metabolism will be evaluated in kidney tissue of a couple of diabetes mice and patients with diabetic nephropathy. To evaluate the effects of chronic hyperglycemia on glycolysis ability of podocytes, the key enzyme of glycolysis (PKM2) will be deleted exclusively in podocyte via PKM2fl/fl ×Podocin Cre model. The metabolic characteristics of glucose and amino acid will be determined by seahorse analyzer and isotope tracing approaches. Since Amino acids are well-known sensitive substrates of mTOR, and inhibition of mTOR signal will be applied to correct the metabolism disorder of podocyte in diabetic nephropathy. In perspective of energy metabolism, podocyte could be targeted to prevent diabetic nephropathy.