从SnoN对TGF-β1/Smad信号通路负调控角度探索黄芪汤对肾间质纤维化的保护机制

Renal interstitial fibrosis(RIF)constitutes a common endpoint of various progressive kidney diseases which leads to the loss of nephrons and impairment of renal function ultimately resulting in end stage renal diseases (ESRD). Smad-dependent signaling pathway is considered the most classic signaling pathway in TGF-β1-induced fibrosis. Our previous research showed that HuangQi decoction, a compound from traditional Chinese medicine that can effectively ameliorate renal interstitial fibrosis (RIF) via TGF-β1/Smad signaling pathway,but the mechanism of Ski-related novel gene N(SnoN), the most important suppressors of TGF-β1/Smad signaling has not been fully elucidated.Therefore, the expression levels of SnoN and three main E3 ubiquitin-ligases interacting with SnoN were detected in this study, while the role of HuangQi decoction was evaluated in RIF. SnoN-F and SnoN-M transfection were conducted to further investigating the role of SnoN and its proteasome-mediated degradation in TGF-β1/Smad signaling pathway. The study presents a new perspectives based on the negative regulation, to understand the mechanism of SnoN in regulating TGF-β1/Smad signaling pathway, to verify the role of HuangQi decoction in renal interstitial fibrosis.

肾间质纤维化（RIF）是各种慢性肾脏病进展至终末期肾衰竭的共同病理基础。转化生长因子-β1（TGF-β1）及其下游信号分子的激活是公认的肾间质纤维化发生、发展的关键驱动因素。在前期研究中，我们发现传统中药复方黄芪汤通过下调TGF-β1/Smad信号通路改善肾间质纤维化。核转录抑制因子SnoN是TGF-β1/Smad信号最重要负调控因子，黄芪汤对SnoN的表达及其泛素化降解起着怎样的作用，国内外未见相关的报道。因此，本申项拟通过检测SnoN在RIF中的表达及泛素化降解，以及黄芪汤对该过程的影响，进一步探索黄芪汤干预RIF的机制；通过体内外转染技术，观察上调SnoN并抑制其泛素化降解对TGF-β1/Smads信号的作用，从而进一步明确黄芪汤干预RIF的作用机制。而这方面的研究使我们从纤维化过程的负调控角度，对肾间质纤维化的发生发展机制有新的认识。

肾间质纤维化（Renal interstitial fibrosis,RIF）是各种慢性肾脏病（Chronic Kidney disease,CKD）进展至终末期肾病的共同途径和主要病理基础。TGF-β1的异常活化是肾间质纤维化进展的关键，而Snon可负向调控该信号。前期研究证实，黄芪汤可延缓肾间质纤维化进展。泛素介导的蛋白降解途径对SnoN的活性起着主要的调控作用。因此，针对SnoN的泛素-蛋白酶体降解途径的研究，可能为阻断TGF-β1的过表达，减慢甚至终止肾纤维化的进展，提供一个新的治疗思路。因此，我们首先开展了黄芪汤改善小鼠肾纤维化进程的机制探究后，进一步观察其与TGF-β1下游信号通路的相互作用。其次，我们构建了肾间质纤维化体内模型，观察 SnoN在RIF中的表达及泛素化降解与黄芪汤的关系。本项目阐明了中药复方黄芪汤针对SnoN的泛素-蛋白酶体降解途径干预TGF-β1的过表达，从而为减慢甚至终止肾间质纤维化的进展提供一个新的治疗思路。