寨卡病毒NS2A蛋白靶向SERCA2导致内质网Ca2+稳态失衡和神经细胞损伤的分子机制研究

寨卡病毒感染可致胎儿神经系统发育异常和小头症，其发病机制不完全明了。Ca2+是重要的细胞信号分子，而SERCA2是内质网ER上的主要钙调蛋白。病毒感染后SERCA2可将胞质Ca2+泵入ER腔内以平衡ER应激反应。我们观察到寨卡病毒感染或其非结构蛋白NS2A可诱导星形胶质细胞中SERCA2的高表达、ER应激标记分子表达异常和Ca2+在胞浆内聚集，最终细胞死亡。我们发现NS2A能与SERCA2相互作用；敲低SERCA2可减少寨卡病毒导致的细胞死亡。我们因而推测寨卡病毒NS2A蛋白靶向SERCA2造成胞内Ca2+稳态和ER应激失衡，可能是损伤神经细胞的重要作用模式。本项目将研究 ：1）寨卡病毒NS2A在神经细胞诱导SERCA2高表达和与其作用的生化机制； 2）NS2A调控SERCA2以诱导ER应激失衡和神经细胞损伤的分子机制。本项目将为深入解析寨卡病毒致病机制及研发抗寨卡病毒新药提供新思路。

The infection of Zika virus (ZIKV) can induce neurodevelopmental abnormalities and microcephaly in fetuses, but the pathogenesis is not fully understood. Ca2+ is an essential cell signaling molecule. SERCA2, as the major calcium regulated protein of the endoplasmic reticulum, pumps cytoplasmic Ca2+ into the ER lumen to balance the ER stress response after viral infection. We recently observed that either ZIKV or viral nonstructural protein NS2A induced high expression of SERCA2 in astrocytes. ZIKV caused abnormal expression of ER stress marker molecules and intracellular Ca2+ accumulation，eventually cell death. We also found ZIKV NS2A interacted with SERCA2 and knockdown of SERCA2 using shRNA technology decreased the cell mortality induced by ZIKV. We postulated that ZIKV NS2A protein targeting SERCA2 caused disregulation of intracellular Ca2+ homeostasis and ER stress, which is an important molecular mechanism for the neurotoxic effects of ZIKV to neural cells. In this project, we will investigate : 1) Biochemical mechanism of Zika virus NS2A induced high expression of SERCA2 in neural cells and its role; 2) Molecular mechanisms of NS2A inducing ER stress imbalance and neuronal cell injury through regulation of SERCA2. Our study will provide new insights for the in-depth analysis of Zika virus pathogenesis and the development of new anti-Zika virus drugs.