Elucidating the Entry Mechanism of Ebola Viruses

描述(申请人提供)：埃博拉和马尔堡病毒属于丝状病毒科，可引起致命的出血热，特征是广泛的组织破坏。出于安全考虑，这些病毒被指定为生物安全4级制剂。部分出于安全考虑，埃博拉病毒进入机制和致病机制的阐明进展受阻。然而，已经建立了基于病毒伪分型技术的各种替代系统来研究埃博拉病毒的入侵机制。在这项应用中，我们证明了埃博拉糖蛋白(GP)可以有效地整合到HIV病毒颗粒上，并且假型病毒粒子具有很强的传染性，正如其他人所报道的那样。更重要的是，我们表明，我们可以利用这个系统作为一个强大的进入测试，以阐明埃博拉病毒的进入机制。我们的初步结果清楚地说明了我们如何使用这个伪型系统来剖析埃博拉GP的两个亚单位(GP1和GP2)在受体识别和病毒进入中的作用。这项应用将集中于以下具体目标：(1)表征GP2发夹的带电残基在埃博拉病毒进入中的作用。(2)埃博拉病毒入境过程中GP1受体结合区的分析。(3)潜在的埃博拉受体的鉴定和特性(S)。这些研究将提供有关埃博拉糖蛋白如何与细胞受体(S)相互作用以及埃博拉糖蛋白如何介导有效的膜融合和病毒进入的重要信息。此外，阐明GP1和GP2在埃博拉病毒进入中的作用将有助于我们设计有效的埃博拉病毒进入抑制剂，从而可能提供治疗埃博拉病毒感染和疾病的方法。因此，本申请中提出的研究工作不仅对于阐明埃博拉病毒的基本进入机制具有重要意义，而且对于开发潜在的强大治疗手段对抗这种致命病原体也具有重要意义。

DESCRIPTION (provided by applicant): Ebola and Marburg viruses belong to the family Filoviridae and can cause fatal hemorrhagic fevers characterized by widespread tissue destruction. Because of the safety concerns, these viruses are designated as the bio-safety level 4 agents. Progress in elucidation of the mechanisms of Ebola entry and pathogenesis has been hampered partly due to the safety concern. However, various surrogate systems based on the viral pseudotyping technique have been established to investigate the entry mechanism of Ebola viruses. In this application, we demonstrate that Ebola glycoprotein (GP) can be efficiently incorporated onto HIV viral particles, and the pseudotyped virions are highly infectious, as reported by others. More importantly, we show that we can use this system as a powerful entry assay to elucidate the entry mechanism of Ebola viruses. Our preliminary results clearly illustrate how we can use this pseudotyped system to dissect the roles of both subunits (GP1 and GP2) of Ebola GP in receptor recognition and viral entry. This application will focus on the following specific aims: (1) Characterization of the roles of the charged residues of the GP2 hairpin in Ebola entry. (2) Analysis of the receptor binding region of GP1 in Ebola entry. (3) Identification and characterization of the potential Ebola receptor(s). These studies will provide important information regarding how Ebola GP interacts with the cellular receptor(s) and how Ebola GP mediates efficient membrane fusion and viral entry. Furthermore, elucidation of the roles of GP1 and GP2 in Ebola entry will help us design effective Ebola entry inhibitors which may provide therapeutic treatments against Ebola infection and disease. Therefore, the research work proposed in this application is not only important for elucidating the basic entry mechanism of Ebola viruses, but also important for developing potentially powerful treatments to combat this deadly pathogen.