EphA2介导HCMV感染神经胶质细胞及其机制

Glioblastoma is the most aggressive and the most common primary malignancy of the central nervous system,and people found that the EphA2 receptor tyrosine kinase was overexpressed in glioblastoma tumor-propagating cells with stem-like characteristics.In recent years,more and more people found that human Cytomegalovirus（HCMV）infection was associated with variety kinds of tumors,and the relationship between glioblastoma and HCMV was was discovered almost twenty years ago.However, the virus receptor mediating HCMV infection of neural glia cell is still undefined and the underlying molecular mechanism(s) is also unclear. Recently,We found that knock-down of EphA2 in glioblastoma cell remarkably decreased HCMV infection efficiency, while overexpression of EphA2 significantly enhanced HCMV infection,and specific EphA2 inhibitor inhibited HCMV infection in a dose-dependent manner. Furthermore, we found that EphA2 interacts with HCMV glycoprotein gH. Based on the preliminary data, this study is aimed to determine the function of EphA2 in mediating HCMV binding or internalization; to determine whether EphA2 interacts with gH in a direct or indirect way and the interacting domain; to determine EphA2 function in vivo based on mouse Cytomegalovirus (MCMV) infection model. Taken together, this study will help us to understand the mechanism involved in HCMV infection of neural glia cell, and will offer molecular basis in the developing glioblastoma vaccine and potential drugs to prevent HCMV infection.

胶质母细胞瘤是中枢神经系统最常见的原发恶性肿瘤，研究表明在具有干细胞样的胶质母细胞瘤细胞中EphA2高表达。近年来越来越多的研究发现人巨细胞病毒（HCMV）感染与多种肿瘤密切相关，其中与胶质母细胞瘤相关的研究已近二十年，但其感染神经胶质细胞的受体及机制仍不清楚。我们发现在胶质母细胞瘤细胞中沉默EphA2显著降低HCMV感染效率，过表达则显著提高其感染效率，EphA2特异性抑制剂呈剂量依赖性的抑制HCMV感染，且EphA2能与HCMV糖蛋白gH相互作用。本项目将进一步明确EphA2在感染中是介导病毒“粘附”拟或“进入”细胞的功能，鉴定EphA2与病毒糖蛋白相互作用方式和结构域，探讨其介导病毒感染的途径，以及以鼠巨细胞病毒（MCMV）为模型，探讨EphA2在体内介导MCMV感染的功能。这将为阐明HCMV感染神经胶质细胞机制、研制预防性疫苗和筛选干预感染药物提供依据。

人类巨细胞病毒（HCMV）是一种人类疱疹病毒，与先天性感染后病毒引起的出生缺陷有关。在免疫缺陷的病人中，HCMV可引起威胁生命安全的感染。越来越多的研究表明HCMV与肿瘤相关，其中就包括中枢神经系统最为常见的原发恶性肿瘤：胶质母细胞瘤。在本研究中我们发现EphA2在胶质母细胞瘤中表达上调，且与患者预后不良相关。沉默EphA2的表达可以抑制HCMV的感染，而过表达EphA2可以促进HCMV的感染，这表明EphA2是介导HCMV感染的重要宿主因子。同时，我们发现EphA可以与HCMV的糖蛋白gH/gL相互作用，介导病毒与细胞的融合。更为重要的是HCMV感染可以被EphA2抗体和抑制剂阻断，在体外培养的胶质母细胞瘤类器官也证实了HCMV感染可以被EphA2抑制剂阻断。综上，我们首次提出EphA2是介导HCMV感染胶质母细胞瘤细胞的宿主因子，也是一个治疗的潜在靶标。此外，我们还发现R9AP是介导EBV感染上皮细胞和B细胞的关键受体，是一个治疗的潜在靶标。