Ebola virus VP24 alters hnRNP C nuclear import: implications for replication

埃博拉病毒 VP24 改变 hnRNP C 核输入：对复制的影响

• 批准号: 7924715
• 负责人: Reed Solomon Shabman
• 金额: $ 5.05万
• 依托单位: ICAHN SCHOOL OF MEDICINE AT MOUNT SINAI
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-01 至 2011-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7924715
• 关键词: Address; Binding; Biological Assay; Cell Line; Cell Nucleus; Complement component C1s; Cytoplasm; Data; Development; Disease Outbreaks; Ebola virus; Family; Family member; Goals; Heterogeneous-Nuclear Ribonucleoproteins; Human; Immune response; Infection; Interferons; Karyopherins; Mediating; Microbe; Molecular; Nuclear; Nuclear Import; Nuclear Translocation; Nucleocapsid; Pharmaceutical Preparations; Play; Protein Biosynthesis; Proteins; RNA Viruses; Role; Signal Transduction; Source; System; Testing; Tetracyclines; Therapeutic; Translations; Viral; Viral Hemorrhagic Fevers; Viral Proteins; Virus; Virus Diseases; Virus Replication; Work; base; design; hnRNP Complexes; inhibitor/antagonist; interest; member; overexpression; prevent; public health relevance; small molecule; viral RNA; virus pathogenesis

DESCRIPTION (provided by applicant): Ebola virus (EBOV) infection of humans often results in severe hemorrhagic fever which is lethal in up to 90% of infected cases. Therefore, understanding the molecular mechanisms of Ebola virus pathogenesis is essential for development of successful therapeutics. Previous work has demonstrated that EBOV VP24 prevents type I and II Interferon (IFN) signaling by binding to the specific members of the karyopherin a (KPNA) family of nuclear import proteins to prevent nuclear accumulation of STAT-1. The ability of VP24 to block IFN signaling is one example of how EBOV can suppress the host response to infection. The goal of this proposal is to test if VP24 binding to KPNAs prevents binding and subsequent nuclear translocation of additional cellular proteins. We hypothesize VP24 blocks the nuclear import of additional cellular proteins and redistributes these proteins to the cytoplasm to promote EBOV replication. To this end, we have demonstrated that the heterogeneous ribonuclear protein C1/C2 complex (hnRNP C1/C2) interacts with members of the KPNA family, and that hnRNP C1/C2 binding to KPNA1 is diminished in the presence of VP24. VP24 inhibition of hnRNP C1/C2 binding to KPNA1 is of great interest since hnRNP CI/ C2 has been shown to play an important role in the replication cycle of other RNA viruses. Therefore, the first aim of this proposal is to fully characterize the interactions between VP24, the NPI-I KPNA family members and hnRNP C1/C2 and determine if VP24/KPNA interactions are sufficient to prevent hnRNP CI/ C2 nuclear accumulation. Since hnRNP C1/C2 facilitates both viral RNA and protein synthesis in other systems, the second aim will test if hnRNP C1/C2 interacts with EBOV RNA and impacts viral replication and/or protein translation. The third aim of this proposal focuses on developing assays to screen for small molecule inhibitors against VP24 IFN antagonism. Identifying small molecular inhibitors that impair EBOV mediated IFN antagonism (and likely replication) would be very useful for treating EBOV. PUBLIC HEALTH RELEVANCE: EBOV is an extremely lethal microbe and while infection is rare, it is possible that additional outbreaks either from a natural or unnatural source could occur. The aims presented in this proposal further define how EBOV VP24 modulates the normal cellular nuclear import and identify small compounds to inhibit VP24 function! Data obtained from these studies could strengthen the fields' understanding of the molecular mechanism of EBOV pathogenesis as well as identify effective drugs to inhibit EBOV replication.

描述（由申请人提供）：埃博拉病毒（EBOV）感染人类通常会导致严重的出血热，在高达90%的感染病例中是致命的。因此，了解埃博拉病毒致病的分子机制对于开发成功的治疗方法至关重要。先前的工作已经证明，EBOV VP 24通过结合核输入蛋白的核转运蛋白a（KPNA）家族的特定成员来防止STAT-1的核积累，从而防止I型和II型干扰素（IFN）信号传导。VP 24阻断IFN信号传导的能力是EBOV如何抑制宿主对感染的反应的一个例子。本提案的目的是测试VP 24与KPNA的结合是否阻止了其他细胞蛋白的结合和随后的核转位。我们假设VP 24阻断额外细胞蛋白质的核输入并将这些蛋白质重新分配到细胞质以促进EBOV复制。为此，我们已经证明，异质核糖核蛋白C1/C2复合物（hnRNP C1/C2）与KPNA家族的成员相互作用，并且在VP 24存在下，hnRNP C1/C2与KPNA 1的结合减少。VP 24对hnRNP C1/C2与KPNA 1结合的抑制是非常令人感兴趣的，因为hnRNP C1/ C2已显示在其他RNA病毒的复制周期中起重要作用。因此，该提议的第一个目的是充分表征VP 24、NPI-I KPNA家族成员和hnRNP C1/C2之间的相互作用，并确定VP 24/KPNA相互作用是否足以防止hnRNP C1/ C2核积累。由于hnRNP C1/C2在其他系统中促进病毒RNA和蛋白质合成，第二个目的将测试hnRNP C1/C2是否与EBOV RNA相互作用并影响病毒复制和/或蛋白质翻译。该提案的第三个目的集中于开发用于筛选针对VP 24 IFN拮抗作用的小分子抑制剂的测定。鉴定损害EBOV介导的IFN拮抗作用（和可能的复制）的小分子抑制剂将非常用于治疗EBOV。公共卫生相关性：EBOV是一种极其致命的微生物，虽然感染很罕见，但可能会发生来自自然或非自然来源的额外爆发。本提案中提出的目标进一步定义了EBOV VP 24如何调节正常细胞核输入，并确定了抑制VP 24功能的小化合物！从这些研究中获得的数据可以加强该领域对EBOV发病机制的分子机制的理解，并确定有效的药物来抑制EBOV复制。