溶酶体在尿蛋白所致肾小管上皮细胞损伤的自噬流保护机制中的作用

蛋白尿通过损伤肾小管上皮细胞（TEC）使肾小球损伤向肾小管蔓延。而自噬可保护外源性肾毒药物所致TEC损伤。我们前期研究也发现：一方面，尿蛋白（一种内源性肾毒因子）可通过氧化应激途径在自噬通路上游诱导自噬，用雷帕霉素进一步诱导自噬可减轻尿蛋白所致TEC损伤；另一方面，尿蛋白同时可能影响溶酶体功能而导致自噬通路下游受阻，用氯喹抑制溶酶体功能则加剧TEC损伤。基于以上发现，下一步有必要明确尿蛋白如何损伤溶酶体，并进而如何影响自噬对尿蛋白所致TEC损伤的自救作用发挥？本项目拟首先明确尿蛋白对TEC溶酶体的数量、完整性以及酶活性等产生哪些影响；进而用更为直观方法进一步验证自噬通路下游是否因溶酶体功能受损而受阻；最后探讨增加和保护溶酶体功能，以通畅自噬通路和提高自噬流量能否减轻尿蛋白对TEC损伤。本研究旨在明确溶酶体在尿蛋白所致TEC损伤的自噬流保护机制中的作用，为防治蛋白尿相关TEC损伤寻找新靶点。

Proteinuria spread injury from glomerulus to tubules by directly damaging tubular epithelial cells (TEC). Recent studies revealed that autophagy prevent TEC from injury induced by exogenous nephrotoxic drugs. Our previous study also found that proteinuria, a endogenous nephrotoxic factor, induced autophagy through oxidative stress pathway and further induced autophagy by rampamycin attenuated TEC injury. On the other hand, we also found that urianry proteins might block autophagy pathyway by inducing lysosome injury, and further inhibited the function of lysosomes by chroloque aggregated TEC damage. The above results demostrated that autophagy related to TEC injury induced by urinary proteins, and also indicated that autophagic flux was not smooth in this state. The further work is needed to investigate how urianry proteins affect lysosomes and then affect the pretective role of atuophagic flux on TEC. We firstly plan to make clear the effects of proteinuria on lysosomal number, memembrane permeability, enzyme activities in TEC. Second, whether urinary proteins hamper the fusion of autophagosomes to lysosomes and impair the degradation of autophagosomes in lysosmes will be confirmed by a newly reported method. Lastly, we plan to explore whether improving lysosome function to unobstruct autophagy pathway and enhance autophagy flux can exert protective effects on TEC injury induced by urinary proteins. The purpose of the present research is to ascertain the role of lysosomes on autophagy flux protecting TEC injury induced by proteinuria to explore a new therapy target for renal tubulointerstitial lesion related to proteinuria.