Mechanism, Function, and Exploitation of Influenza A Virus-Activated Cell Death

甲型流感病毒激活的细胞死亡的机制、功能和利用

• 批准号: 10247652
• 负责人: SIDDHARTH BALACHANDRAN
• 金额: $ 57.79万
• 依托单位: RESEARCH INST OF FOX CHASE CAN CTR
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-09-25 至 2022-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10247652
• 关键词: Adult Respiratory Distress Syndrome; Animals; Apoptosis; Avian Influenza; Avian Influenza A Virus; Binding; Cell Culture Techniques; Cell Death; Cell Death Signaling Process; Cells; Cessation of life; Clinical; Double-Stranded RNA; Epithelial; Epithelial Cells; FDA approved; Fibroblasts; Goals; Hand; Host Defense Mechanism; Human; Immunologics; Individual; Infection; Influenza A Virus, H5N1 Subtype; Influenza A Virus, H7N9 Subtype; Influenza A virus; Knowledge; Lead; Left; Lower respiratory tract structure; Lung; Mediating; Modeling; Molecular; Mus; Necrosis; Pathogenesis; Pathogenicity; Pathologic; Pathway interactions; Pharmacology; Phosphotransferases; Predisposition; Proteins; Public Health; RIPK3 gene; RNA; RNA Viruses; Reporter; Role; Signal Pathway; Signal Transduction; System; Testing; Therapeutic; Time; Tissues; Viral Pathogenesis; Virulent; Virus; Virus Diseases; Virus Replication; airway epithelium; base; cell type; genomic RNA; immunopathology; in vivo; influenza virus strain; inhibitor/antagonist; kinase inhibitor; lung injury; macrophage; mortality; mouse model; novel; novel therapeutics; nucleic acid binding protein; pandemic disease; prevent; respiratory; sensor; viral RNA

PROJECT SUMMARY/ABSTRACT Influenza A viruses (IAV) kill most of the cell types in which they replicate, both in cell culture and in infected lungs in vivo. While regulated cell death represents a host defense mechanism that limits both virus spread and host immunopathology early in an infection, unbridled cell death, particularly necrosis, can lead to severe degradation of bronchioalveolar epithelia and consequent mortality despite control of virus replication in vivo. Indeed, severe illness following infection with highly pathogenic strains of IAV is well-correlated with widespread pulmonary epithelial cell death and bronchioalveolar tissue damage in humans. Despite this, remarkably little is known of the molecular mechanisms by which IAV activates cell death in relevant lung cell types. Thus (1) understanding the mechanisms by which IAV triggers cell death, (2) determining the identity and importance of lung cell types that die by these mechanisms during IAV infection in vivo; and (3) determining if pharmacological manipulation of cell death represents a new therapeutic entry-point for respiratory IAV are each important unmet objectives. We have recently discovered a mechanism of cell death that appears to account for almost all IAV- activated death in infected airway epithelial cells. This pathway is initiated when the protein DAI senses IAV genomic RNA and nucleates the kinase RIPK3. RIPK3 then activates parallel pathways of programmed necrosis (necroptosis), as well as apoptosis. Necroptosis downstream of RIPK3 relies on MLKL and apoptosis on FADD, such that deletion of DAI, RIPK3, or MLKL+FADD renders mice extraordinarily susceptible to respiratory IAV replication and lethality. Remarkably, eliminating MLKL alone has no discernible effect, demonstrating that the FADD apoptosis axis can fully compensate for loss of MLKL and necroptosis. To our knowledge, these findings represent the first description of a dedicated IAV activated cell death pathway, the first implication of DAI as a sensor of RNA viruses, and the first identification of a virus that triggers both apoptosis and necroptosis downstream of RIPK3. The redundancy of necroptosis with apoptosis to IAV clearance also provides an unexpected therapeutic opportunity in cases where necrotic death is implicated in IAV pathogenesis. Based on these and other observations, the goals of this proposal are to: (1) identify the molecular mechanisms by which the DAI-RIPK3 axis recognizes IAV and activates cell death; (2) employ cutting-edge mouse reporter models to isolate and identify lung cell types that succumb to IAV by RIPK3-driven apoptosis versus necroptosis, and determine in which of these cell types is RIPK3 signaling important for virus control; and (3) test if selective blockade of necroptosis will have clinical benefit following infection with highly-pathogenic strains of IAV. Successful completion of these Aims has the potential to transform our understanding of IAV pathogenesis, with immediate clinical ramifications.

项目摘要/摘要 流感病毒（IAV）在细胞培养和感染中杀死了它们复制的大多数细胞类型 体内肺。而受调节的细胞死亡代表了一种宿主防御机制，该机制限制了病毒扩散和 宿主免疫病理学早期感染，无限制的细胞死亡，尤其是坏死，可能导致严重 尽管控制了体内病毒复制，但支气管肺泡上皮的降解和随之而来的死亡率。 确实，高度致病性IAV感染后的严重疾病与广泛相关 人类肺上皮细胞死亡和支气管肺泡组织损伤。尽管如此，很少有 已知IAV激活相关肺部细胞类型的细胞死亡的分子机制已知。因此（1） 了解IAV触发细胞死亡的机制，（2）确定的身份和重要性 在体内IAV感染期间这些机制死亡的肺细胞类型； （3）确定药理学是否 细胞死亡的操纵代表了呼吸IAV的一个新的治疗切入点 目标。我们最近发现了一种细胞死亡的机制，该机制几乎解释了几乎所有的IAV- 感染气道上皮细胞激活死亡。当蛋白质dai感觉IAV时，该途径将开始 基因组RNA并成核激酶RIPK3。然后RIPK3激活编程坏死的平行途径 （坏死性）以及凋亡。 RIPK3下游的坏死性依赖于FADD上的MLKL和凋亡 因此删除了DAI，RIPK3或MLKL+FADD，使小鼠非常容易受到呼吸IAV的影响 复制和致死性。值得注意的是，仅消除MLKL没有明显的影响，表明 FADD凋亡轴可以充分补偿MLKL和坏死的损失。据我们所知，这些发现 表示专用IAV激活的细胞死亡途径的第一个描述，这是DAI作为一个的第一个含义 RNA病毒的传感器，以及触发细胞凋亡和坏死性的病毒的首次鉴定 RIPK3的下游。凋亡对IAV清除的坏死性冗余也提供了 在与IAV发病机理有关的坏死死亡的情况下，意外的治疗机会。基于 这些和其他观察结果，该提案的目标是：（1）确定分子机制 DAI-RIPK3轴识别IAV并激活细胞死亡。 （2）采用尖端的鼠标记者模型 分离并鉴定通过RIPK3驱动的凋亡与坏死的肺细胞类型，并 确定其中哪种细胞类型对病毒控制很重要； （3）测试是否有选择性 在高度致病的IAV感染后，对坏死性的封锁将具有临床益处。 这些目标的成功完成有可能改变我们对IAV发病机理的理解 立即临床分析。