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: 10446481
• 负责人: SIDDHARTH BALACHANDRAN
• 金额: $ 74.23万
• 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 2027-08-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10446481
• 关键词: Alveolar Macrophages; Amino Acids; Apoptosis; Birds; Cell Death; Cell Death Signaling Process; Cell Nucleus; Cells; Cessation of life; Chiroptera; Clinical; Cytoplasm; Cytotoxic T-Lymphocytes; Disease; Elements; Evolution; Funding; Gene Expression; Genes; Genetic Polymorphism; Genetic Transcription; Genetic Variation; Goals; Hand; Host Defense; Human; Immunity; Infection; Inflammation; Inflammatory; Influenza; Influenza A virus; Knowledge Discovery; Left; Ligands; Lung; Mediating; Modeling; Mus; Nature; Necrosis; Nuclear; Organism; Orthomyxoviridae; Pathogenesis; Pathogenicity; Pathology; Pathway interactions; Phosphotransferases; Proteins; Public Health; Publishing; RIPK3 gene; RNA; Reporting; Role; Rupture; Signal Transduction; Structure; Testing; Tissues; Viral; Viral Pathogenesis; Virulent; Virus; Virus Diseases; anti-influenza; base; cell type; clinically relevant; in vivo; influenza virus strain; influenzavirus; insight; pandemic disease; programs; recruit; sensor; viral RNA

PROJECT SUMMARY/ABSTRACT Influenza A virus (IAV) triggers the death of most cell types in which it replicates, both in culture and in vivo. In 2016, we described an IAV-activated cell death pathway which accounts for almost all IAV-activated death in infected pulmonary cells. Over that past funding cycle, we showed that this pathway is initiated when the host sensor protein ZBP1 detects viral Z-RNAs and activates RIPK3 kinase. RIPK3 then triggers parallel, redundant pathways of programmed necrosis (necroptosis) and apoptosis. These studies have outlined the dominant cell death pathway activated by IAV in infected lungs. They have also demonstrated that ZBP1 is an RNA sensing protein, and that the RNA structures it recognizes are Z-RNAs, which are unique, left-handed double-helical RNA species that had not previously been thought to occur in nature. We have now made several intriguing new discoveries that set the stage for this application. First, we found that the Z-RNAs produced during IAV infections are not just viral in origin, but host cell-derived as well. Second, we observed that in alveolar macrophages (AMs), unlike in all other lung cell types tested, ZBP1 activation does not result in cell death, but instead in a non-cytolytic transcriptional program essential for protection against IAV lethality. Third, we found that necroptosis during IAV infections is activated not in the cytoplasm, but in the nucleus, resulting in nuclear rupture. Such `nuclear necroptosis' is highly inflammatory, and is a major driver of the pathogenesis during severe influenza. Finally, we have obtained important new insight into the coevolution of IAV with the necroptosis machinery in birds and bats, the two major natural hosts of these viruses. While birds simply do not express ZBP1, we have found that bats possess a single amino acid alteration in RIPK3 which selectively abrogates necroptosis (but not apoptosis) signaling, potentially explaining how these organisms tolerate such a large diversity of IAV subtypes. To our knowledge, these discoveries provide the first evidence that endogenous Z-RNAs may function as innate ligands for ZBP1 in anti-IAV immunity, that ZBP1 has non-cytolytic functions during IAV infections, and that a IAV activates a unique, hyper-inflammatory form of necroptosis from the nucleus. They also provide fresh evolutionary insight into how IAV strains are tolerated in their natural reservoirs, but can activate pathogenic necroptosis in humans. Based these and other observations, the goals of this proposal are to (1) to identify and characterize endogenous Z-RNA ligands for ZBP1, and to determine their importance to ZBP1 activated cell death in IAV-infected cells; (2) to delineate the mechanism and function of non-cytolytic ZBP1 signaling in AMs; and (3) to understand the role of nuclear necroptosis in influenza pathogenesis and in evolution. These studies unite two labs with expertise in ZBP1 signaling (Balachandran) and IAV pathogenesis (Thomas), and their successful completion stands to provide pioneering insight into the mechanism and function of ZBP1-initiated cell death during IAV infections, with important clinical and evolutionary ramifications.

项目总结/摘要 甲型流感病毒（IAV）在培养物和体内均引发其在其中复制的大多数细胞类型的死亡。在 2016年，我们描述了一种IAV激活的细胞死亡途径，该途径几乎解释了所有的IAV激活的死亡。 感染的肺细胞在过去的资助周期中，我们表明，当东道国 传感器蛋白ZBP 1检测病毒Z-RNA并激活RIPK 3激酶。RIPK 3然后触发并行冗余 程序性坏死（坏死性凋亡）和凋亡的途径。这些研究概述了占主导地位的细胞 IAV在受感染肺部激活的死亡途径。他们还证明了ZBP 1是一种RNA传感器， 蛋白质，它识别的RNA结构是Z-RNA，这是独特的，左手双螺旋 以前认为自然界中不存在的RNA种类。我们现在已经做了几个有趣的 新的发现为这一应用奠定了基础。首先，我们发现在IAV过程中产生的Z-RNA 感染不仅是病毒来源的，也是宿主细胞来源的。其次，我们观察到，在肺泡中， 与所有其他测试的肺细胞类型不同，ZBP 1激活不会导致细胞死亡，但 而是在对IAV致死性保护所必需的非溶细胞转录程序中。第三，我们发现 IAV感染期间的坏死性凋亡不是在细胞质中激活，而是在细胞核中激活，导致细胞核坏死。 破裂这种“细胞核坏死性凋亡”是高度炎症性的，并且是肿瘤发生过程中发病机制的主要驱动因素。 严重的流感最后，我们获得了重要的新见解，IAV的共同进化与 鸟类和蝙蝠的坏死性凋亡机制，这些病毒的两个主要自然宿主。而鸟类则不会 表达ZBP 1，我们发现蝙蝠在RIPK 3中具有一个单一的氨基酸改变， 消除了坏死性凋亡（但不是凋亡）信号，可能解释了这些生物体如何耐受这种 IAV亚型的多样性。据我们所知，这些发现首次证明， 内源性Z-RNA可能在抗IAV免疫中作为ZBP 1的天然配体发挥作用，ZBP 1具有非细胞溶解性， 在IAV感染过程中发挥作用，IAV激活了一种独特的，高度炎症形式的坏死性凋亡， 原子核他们还提供了新的进化见解，如何IAV菌株是容忍在其自然 水库，但可以激活人类的致病性坏死性凋亡。根据这些和其他观察，目标 该建议的目的是（1）鉴定和表征ZBP 1的内源性Z-RNA配体，并确定 它们在ZBP 1激活的IAV感染细胞中的细胞死亡中的重要性;（2）阐明其机制和功能 非溶细胞ZBP 1信号在AM中的作用;（3）了解核坏死性凋亡在流感中的作用 发病机制和进化。这些研究联合了两个在ZBP 1信号传导方面具有专业知识的实验室（Balachandran） 和IAV发病机制（托马斯），他们的成功完成站在提供开创性的见解， ZBP 1在IAV感染过程中启动的细胞死亡的机制和功能，具有重要的临床和 进化的结果