C1qR维持eIF2α磷酸化保护急性肾损伤的作用及机制研究

Acute kidney injury (AKI) is a common clinical critical disease, excessive inflammatory response and renal tubular epithelial cell apoptosis are closely related to the development of AKI. However, the underlying mechanism is unknown. C1qR is a key inflammatory regulator and closely related to apoptosis. Our study found that C1qR plays an important protective role in AKI by inhibiting inflammatory reaction and reducing apoptosis. The phosphorylation of eIF2α has an anti-apoptotic effect. Furthermore, phosphorylation of eIF2α may participate in the protective role in AKI. Src activation can induce apoptosis in renal tubular epithelial cells. Therefore, we presume that C1qR might play an anti-apoptotic and protective role by inhibition of Src activation mediated signal pathway and maintaining the phosphorylation of eIF2α in AKI. Based on this, in this study, by adopting C1qR transgenic mice, we will firstly reveal the protective role of C1qR and maintenance of eIF2α phosphorylation in AKI. Then, by using primary renal tubular epithelial cells, we plan to further clarify the effect and mechanism of C1qR in cell injury via maintaining the phosphorylation of eIF2α. The aim of this study is to uncover the protective role and underlying mechanism of C1qR in AKI and provide a new theoretical basis and new target for the clinical prevention and control of AKI.

急性肾损伤（AKI）是临床常见的危急重症，AKI与炎症反应和肾小管上皮细胞凋亡密切相关，但机制不明。C1qR是一个关键的炎症调节因子，与细胞凋亡密切相关。我们前期发现C1qR通过抑制炎症反应、减少细胞凋亡在AKI中发挥保护作用。eIF2α磷酸化具有抗凋亡保护作用。进一步的研究提示eIF2α磷酸化可能参与了C1qR对AKI的保护效应。Src活化可以诱导肾小管上皮细胞凋亡。我们推测C1qR可能通过抑制Src活化介导的Akt/mTOR的信号通路来维持eIF2α磷酸化水平进而发挥抗凋亡保护作用。本项目拟采用C1qR转基因小鼠，全面阐明C1qR维持eIF2α磷酸化在AKI中的保护作用，然后以小鼠原代肾小管上皮细胞为体外研究对象，进一步明确C1qR维持eIF2α磷酸化保护细胞损伤的作用及分子机制。本项目旨在揭示C1qR在AKI中的保护作用和关键调控点，为临床防治AKI提供新的理论依据和干预靶点。

我们的研究发现C1qR可以促进肾小管上皮细胞凋亡和炎症反应，加重AKI损伤。本课题通过基因敲除小鼠，流式细胞术、免疫染色、细胞共培养等方法与技术，对C1qR在AKI病理过程的分子机制进行了初步研究。我们首次在AKI患者的肾活检标本中发现C1qR表达增加；同时，AKI患者血清中可溶性sC1qR (soluble C1qR)的水平也是显著升高，且AKI患者血清中sC1qR水平与血肌酐、尿素氮水平呈正相关，与AKI患者的肾小球滤过率eGFR呈负相关。为了明确C1qR在AKI病理过程中的作用机制，我们建立了缺血再灌注和顺铂致AKI两种小鼠AKI模型。我们发现C1qR在AKI小鼠肾脏组织中的表达均显著增加。进一步的研究发现C1qR在髓系来源的单核细胞中高表达。在炎症的刺激下，髓系单核细胞分化成巨噬细胞分泌可溶性sC1qR促进肾小管上皮细胞凋亡和炎症反应。体外共培养研究表明敲降髓系单核细胞THP-1细胞中C1qR表达或者抑制sC1qR脱落均可以显著降低共培养导致的肾小管上皮细胞凋亡和炎症反应。最后通过基因敲除小鼠证实C1qR敲除可以显著改善AKI病理损伤和肾脏功能。综上所述，本研究明确了C1qR在AKI中的关键作用；阐明了单核细胞分化后致sC1qR脱落促进肾小管上皮细胞凋亡和炎症反应的作用机制，为防治AKI 提供新的理论依据和治疗靶点。项目资助发表SCI论文3篇，待发表2篇 。培养博士研究生1名，硕士研究生1名。项目投入经费21万元，支出10.43万元，各项支出基本与预算相符，结余经费10.57万元，将用于本项目研究后续的支出。