Virulence Mechanisms of Viral Bcl-2 Homologs

病毒 Bcl-2 同源物的毒力机制

• 批准号: 8026437
• 负责人: JOHN C REED
• 金额: $ 47.75万
• 依托单位: SANFORD BURNHAM PREBYS MEDICAL DISCOVERY INSTITUTE
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-12-01 至 2015-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8026437
• 关键词: Address; Adenoviruses; Apoptosis; Apoptotic; Autophagocytosis; BCL2 gene; Binding; Biological Models; Caspase-1; Cells; Cultured Cells; DNA Viruses; Disease; Engineering; Family; Family member; Foundations; Genes; Genome; Goals; Herpesviridae; Homologous Gene; Host Defense; Host Defense Mechanism; Immune response; Inflammation; Inflammatory; Investigation; Knock-in Mouse; Laboratories; Learning; Mediating; Mediator of activation protein; Morbidity - disease rate; Mus; Mutation; Natural Immunity; Pathogenicity; Play; Poxviridae; Process; Protein Family; Proteins; Role; Site; Testing; Therapeutic; Vaccinia virus; Viral; Viral Interference; Viral Proteins; Virulence; Virus; Virus Diseases; base; cytokine; defense response; gammaherpesvirus; human disease; in vivo; inhibition of autophagy; inhibitor/antagonist; member; mortality; mutant; novel; novel strategies; pathogen

DESCRIPTION (provided by applicant): DNA viruses are responsible for extensive morbidity and mortality on a worldwide basis. Viral homologs of anti-apoptotic Bcl-2 family proteins are encoded in the genomes of several classes of DNA viruses. In Vaccinia Virus (VV), a poxvirus-family member that has served as a paradigm for investigations of many aspects of host-pathogen interactions, at least two viral Bcl-2 genes have been identified, F1L and N1L. Neither F1L nor N1L is required for VV infection or replication, but both of these genes make strong contributions to virulence in vivo. Thus, these viral Bcl-2 (vBcl-2) homologs are critically important for in vivo viral pathogenicity of VV. While the anti-apoptotic activity of F1L and N1L is an obvious candidate for explaining their contribution to viral virulence, we have discovered that F1L and N1L have additional functions that include binding to and suppressing the pro-inflammatory actions of NLR-family proteins, important mediators of innate immunity. Viral Bcl-2 proteins are also known to bind Beclin and suppress autophagy, recently recognized as a host defense mechanism against pathogens. We hypothesize the vBcl-2 homologs are multifunctional proteins that utilize 3 discrete mechanisms to thwart host defense mechanisms: (a) suppression of apoptosis; (b) inhibition of autophagy; and (c) interference with NLR-mediated innate immune responses. The hypothesis that we will test is that neutralization by vBcl-2 proteins of each of these 3 classes of host cell targets significantly contributes to virulence. Specifically, we will: (1) Produce site-specific mutations in F1L and N1L that selectively abolish their ability to interact with (a) pro-apoptotic Bcl-2 family proteins [apoptosis]; (b) NLRs [inflammation]; and (c) Beclin [autophagy]; (2) Test the effects of the engineered vBcl-2 proteins on apoptosis, inflammation, and autophagy in cultured cells; (3) Produce recombinant vaccinia viruses with knock-in of F1L and N1L mutants; and (4) Compare the virulence of these recombinant vaccinia viruses in mice. By using VV as a model system, our results will lay a foundation for understanding the role of viral Bcl-2 homologs in viral pathogenicity, thus serving as a paradigm for other DNA viruses that contain vBcl-2 genes and that cause debilitating human diseases. Also, by learning how viruses interfere with apoptosis, autophagy, and inflammation, the information generated may reveal novel strategies for mimicking aspects of vBcl-2 function in therapeutically useful ways for addressing disorders in which excessive apoptosis, autophagy, and inflammation play central roles. PUBLIC HEALTH RELEVANCE: DNA viruses are responsible for extensive morbidity and mortality on a worldwide basis, and yet few therapeutic options are available to counteract these pathogens. Viral homologs of anti-apoptotic Bcl-2 family proteins are encoded in the genomes of several classes of DNA viruses but their roles and mechanism in viral disease are largely unknown. The hypothesis that we will test is that neutralization by viral Bcl-2 proteins of specific classes of host cell proteins significantly contributes to virulence, which will lay a foundation for developing new strategies for viral therapeutics based on disrupting interactions of viral Bcl-2 proteins with their host cell targets.

描述（由申请人提供）：DNA 病毒在全球范围内造成广泛的发病率和死亡率。抗凋亡 Bcl-2 家族蛋白的病毒同源物编码在几类 DNA 病毒的基因组中。痘苗病毒 (VV) 是一种痘病毒家族成员，已成为研究宿主与病原体相互作用的许多方面的范例，在痘苗病毒 (VV) 中，至少已鉴定出两个病毒 Bcl-2 基因：F1L 和 N1L。 F1L 和 N1L 都不是 VV 感染或复制所必需的，但这两个基因都对体内毒力有很大贡献。因此，这些病毒 Bcl-2 (vBcl-2) 同源物对于 VV 的体内病毒致病性至关重要。虽然 F1L 和 N1L 的抗凋亡活性是解释它们对病毒毒力的贡献的明显候选者，但我们发现 F1L 和 N1L 具有其他功能，包括结合和抑制 NLR 家族蛋白的促炎作用，重要的是先天免疫的介质。病毒 Bcl-2 蛋白还可以结合 Beclin 并抑制自噬，最近被认为是宿主针对病原体的防御机制。 我们假设 vBcl-2 同源物是多功能蛋白质，利用 3 种独立的机制来阻止宿主防御机制：(a) 抑制细胞凋亡； (b) 抑制自噬； (c) 干扰 NLR 介导的先天免疫反应。我们将测试的假设是，vBcl-2 蛋白对这 3 类宿主细胞靶标的中和作用显着增强毒力。具体来说，我们将： (1) 在 F1L 和 N1L 中产生位点特异性突变，选择性地消除它们与 (a) 促凋亡 Bcl-2 家族蛋白 [细胞凋亡] 相互作用的能力； (b) NLR[炎症]； (c) Beclin [自噬]； (2) 测试工程化的vBcl-2蛋白对培养细胞凋亡、炎症和自噬的影响； (3) 产生敲入F1L和N1L突变体的重组牛痘病毒； (4)比较这些重组牛痘病毒对小鼠的毒力。通过使用 VV 作为模型系统，我们的结果将为理解病毒 Bcl-2 同源物在病毒致病性中的作用奠定基础，从而为其他含有 vBcl-2 基因并导致人类衰弱疾病的 DNA 病毒提供范例。此外，通过了解病毒如何干扰细胞凋亡、自噬和炎症，所产生的信息可能会揭示以治疗上有用的方式模拟 vBcl-2 功能的新策略，以解决过度细胞凋亡、自噬和炎症发挥核心作用的疾病。 公共卫生相关性：DNA 病毒在全球范围内造成广泛的发病率和死亡率，但对抗这些病原体的治疗方案却很少。抗凋亡 Bcl-2 家族蛋白的病毒同源物编码在几类 DNA 病毒的基因组中，但它们在病毒性疾病中的作用和机制很大程度上未知。我们将测试的假设是，病毒 Bcl-2 蛋白对特定类别宿主细胞蛋白的中和可显着增强毒力，这将为开发基于破坏病毒 Bcl-2 蛋白与宿主细胞相互作用的新病毒治疗策略奠定基础。他们的宿主细胞目标。