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

基本信息

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
项目类别：
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

项目摘要

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.

项目概要/摘要甲型流感病毒 (IAV) 会杀死其复制的大部分细胞类型，无论是在细胞培养物中还是在受感染的细胞中体内的肺。虽然受调控的细胞死亡代表了一种宿主防御机制，可以限制病毒传播和宿主免疫病理学在感染早期，不受限制的细胞死亡，特别是坏死，可导致严重的尽管控制了体内病毒复制，但支气管肺泡上皮细胞退化并导致死亡。事实上，感染高致病性 IAV 菌株后出现的严重疾病与广泛传播密切相关。人类肺上皮细胞死亡和支气管肺泡组织损伤。尽管如此，却很少有已知 IAV 激活相关肺细胞类型细胞死亡的分子机制。因此 (1) 了解 IAV 触发细胞死亡的机制，(2) 确定 IAV 的身份和重要性 IAV 体内感染期间通过这些机制死亡的肺细胞类型； (3) 确定是否有药理作用细胞死亡的操纵代表了呼吸 IAV 的一个新的治疗切入点，但每个重要的尚未得到满足目标。我们最近发现了一种细胞死亡机制，它似乎可以解释几乎所有 IAV- 受感染的气道上皮细胞激活死亡。当蛋白质 DAI 感知到 IAV 时，该途径就会启动基因组 RNA 并使激酶 RIPK3 成核。然后 RIPK3 激活程序性坏死的平行途径（坏死性凋亡）以及细胞凋亡。 RIPK3下游的坏死性凋亡依赖于MLKL，细胞凋亡依赖于FADD，例如，删除 DAI、RIPK3 或 MLKL+FADD 会使小鼠对呼吸道 IAV 异常敏感复制和杀伤力。值得注意的是，单独消除 MLKL 没有明显的效果，这表明 FADD凋亡轴可以完全补偿MLKL的丢失和坏死性凋亡。据我们所知，这些发现代表了专用 IAV 激活细胞死亡途径的首次描述，DAI 作为 RNA病毒传感器，以及首次鉴定出触发细胞凋亡和坏死性凋亡的病毒 RIPK3 的下游。坏死性凋亡与细胞凋亡对 IAV 清除的冗余也提供了在 IAV 发病机制涉及坏死性死亡的病例中，这是意想不到的治疗机会。基于根据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) 采用尖端的小鼠报告模型分离并鉴定通过 RIPK3 驱动的细胞凋亡与坏死性凋亡而死于 IAV 的肺细胞类型，以及确定这些细胞类型中哪些细胞类型的 RIPK3 信号对病毒控制很重要； (3) 测试是否有选择性阻断坏死性凋亡将在感染高致病性 IAV 菌株后具有临床益处。成功完成这些目标有可能改变我们对 IAV 发病机制的理解，直接的临床后果。