RIPK3/MLKL介导的坏死性凋亡在SARS-CoV-2 N蛋白相关急性肾损伤中的作用及机制研究

急性肾损伤(AKI)是COVID-19患者死亡及肾脏不良预后的危险因素，然而其发病机制尚不明确，亟待解决。我们前期研究首次证实SARS-CoV-2 N蛋白在AKI中的致病作用，这一过程明显激活TGF-β/Smad3信号通路。进一步研究发现，过表达SARS-CoV-2 N蛋白可上调介导坏死性凋亡的关键分子RIPK3/MLKL，同时伴有巨噬细胞浸润增多、促炎因子升高，Smad3在其中具有重要作用。通过JASPAR数据库，我们发现RIPK3基因启动子区域具有Smad3结合位点。据此我们提出科学假说，SARS-CoV-2 N蛋白通过Smad3上调RIPK3/MLKL介导的坏死性凋亡及其引起的炎症风暴从而导致AKI。本研究证实RIPK3/MLKL介导的坏死性凋亡及其引起的炎症风暴是SARS-CoV-2 N蛋白通过Smad3导致AKI的关键靶点，为SARS-CoV-2相关AKI的临床治疗提供科学依据。

Acute kidney injury (AKI) is the risk factor for mortality and poor prognosis of renal outcome in COVID-19 patients. However, the pathogenesis of AKI in COVID-19 patients is undefined and urgently waited to be solved. Our preliminary experiments found out that the overexpression of SARS-CoV-2 N protein in mouse kidney induced AKI. It significantly activated the TGF-β/Smad3 signaling pathway. Meanwhile, up-regulation of RIPK3/MLKL which is the key of necroptosis, increased infiltration of macrophage and the elevation of proinflammatory factors were also observed in our study. Smad3 had important effect during this process. Based on the JASPAR database, we found out that the promoter region of RIPK3 had Smad3 binding sites. Therefore, we hypothesis that SARS-CoV-2 N protein induces AKI through the activation of Smad3, leading to RIPK3/MLKL-mediated necroptosis which trigger inflammatory storm. Our study will prove that RIPK3/MLKL-mediated necroptosis which trigger inflammatory storm is the key target for SARS-CoV-2 N protein induced AKI through Smad3. This project aims to provide scientific evidence for the treatment of SARS-CoV-2 associated AKI.