P2受体在产气荚膜梭菌ε毒素导致的溶血中的作用及分子机制研究

产气荚膜梭菌ε毒素（ETX）的致毒机制尚未完全阐明，成为目前研究的焦点。我们在前期研究中发现ETX是一种新的溶血素，并发现ETX通过激活细胞表面的P2受体而致溶血，但ETX激活P2受体的机制以及P2受体导致溶血的机制尚不清楚。阐明ETX溶血的分子机制已成为ETX研究亟待解决的关键问题。预实验发现P2受体不是通过ATP激活，并且发现红细胞内神经酰胺的升高，因此我们推测ETX和受体结合后通过不依赖于ATP的方式激活了P2受体，P2激活后通过激活细胞内鞘磷脂酶从而使细胞进入神经酰胺介导的溶血结局。本项目拟利用人红细胞为主要细胞模型，从ETX结合细胞机制、P2激活机制、P2导致溶血的机制和离子通道四个方面对红细胞溶血机制进行研究。最终阐明从ETX受体结合到P2激活再到溶血的整个信号通路。本课题的顺利实施有望鉴定出ETX毒性作用的关键分子，为ETX中毒的治疗提供靶标，具有重要的经济和生物安全意义。

The mechanism of ETX-induced cytotoxicity remains to be clarified. Therefore, current studies are focused on the mechanism of ETX-induced cytotoxicity. We found ETX is a new hemolysin and ETX-induced hemolysis requires activation of purinergic receptors (P2) in our primary studies. However, how P2 is activated and the molecular mechanism of P2 associated hemolysis is not clear, which urgently need to be resolved. In pre-experiments, we found that activation of P2 does not require ATP and ceramide increased in ETX-treated erythrocytes. We inferred that ETX activates P2 in an ATP-independent manner after binding to a putative receptor. Then, P2 activates intracellular sphingomyelinase, which produce ceramide and finally result in lysis of erythrocytes. This study will be performed using human erythrocytes as the main cell model from perspectives of receptor-binding mechanism, mode of action of P2 receptor activation, mechanism of P2-activation associated hemolysis and ion channel. By then, the mechanism of ETX-induced hemolysis will hopefully have been clarified, which will provide new therapeutic targets for therapy of ETX associated disease. These expected findings are beneficial to economics and biosafety.