Role reversal of MAVS in bacterial sepsis

MAVS 在细菌性脓毒症中的作用逆转

基本信息

批准号：
9759979
负责人：
Markus Bosmann
金额：
$ 48.24万
依托单位：
BOSTON UNIVERSITY MEDICAL CAMPUS
依托单位国家：
美国
项目类别：
财政年份：
2018
资助国家：
美国
起止时间：
2018-08-15 至 2023-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9759979
关键词：
Address Antibodies Antiviral Agents Bacteria Bacterial Infections Bacterial RNA Blood Coagulation Disorders Blood coagulation CRISPR/Cas technology Cells Cessation of life Clinical Trials Coagulation Process Complication Consensus Critical Care Cytosol Data Development Disease Engineering Equilibrium Event Extravasation FDA approved Failure Family Functional disorder Future Gene Deletion Gene Expression Genes Histones Human Immune Immune response Immunosuppression Infection Injury Interleukin-12 Interleukin-6 Knockout Mice Life Microbe Mitochondria Molecular Molecular Target Morbidity - disease rate Mouse Protein Mus Organ Outcome Outer Mitochondrial Membrane Pathway interactions Pattern Phagocytes Pharmacologic Substance Pharmacology Phosphorylation Proteome RNA RNA Helicase Research Resistance Role Sepsis Shapes Signal Pathway Signal Transduction Signaling Protein TBK1 gene TRAF2 gene Testing Therapeutic Intervention Tissues United States Virus Virus Diseases base cytokine cytotoxic effective therapy experimental study extracellular fungus immunopathology injured innovation insight interest macrophage microbial monocyte mortality mouse model neutrophil novel novel therapeutic intervention pathogen pathogenic microbe polymerization polymicrobial sepsis programs protein activation protein degradation sensor septic spatiotemporal transcription factor transcriptome transcriptome sequencing translational study

项目摘要

Sepsis is a frequent and life-threatening complication of microbial infections. It is estimated that more than 750,000 annual cases of sepsis occur in the United States and mortality rates remain around 20-50% despite recent advances of critical care support. In the current absence of FDA-approved pharmacologic compounds, there remains an urgent need for a complete characterization of the underlying cellular and molecular mechanisms of sepsis. The dysregulated host response is a prominent feature during the pathophysiology of bacterial sepsis, but the delicate balance of its integrating molecular pathways appear not entirely clear. Mitochondrial antiviral-signaling protein (MAVS) is an adaptor molecule in the outer mitochondrial membrane and is highly expressed in professional phagocytes. MAVS is activated by the cytoplasmic RNA helicases, RIG- I and MDA5, and confers protection against viral infections. Surprisingly, our preliminary findings suggest deletion of MAVS or RIG-I/MDA5 in mice confers immense resistance to mortality and modulates phagocyte transcriptomes, immunoproteasomes, extracellular traps, IL-6/IL-12 cytokines and blood coagulation during polymicrobial bacterial sepsis. Bacterial RNAs are a viability-associated pathogen patterns (`vita-PAMPs') sensed by the MAVS pathway in macrophages. Together, these findings suggest a detrimental role reversal of MAVS during bacterial sepsis as opposed to protective MAVS pathway functions during infections with viruses. To test our central hypothesis that MAVS signaling provides a lethal switch for obstructing favorable sepsis outcomes, we will pursue 3 specific aims: (1) We will study the gene expression, activation mechanisms, signaling events and functional roles of MAVS in professional phagocytes (macrophages, neutrophils) during polymicrobial bacterial sepsis. For these studies, mice with total or conditional gene deletion of MAVS, or the RIG-I/MDA5 sensors are available. MAVS-deficient human macrophages will be generated using CRISPR-Cas9. (2) We will determine how MAVS-induced transcription factors promote gene expression of immunoproteasome subunits, what the pleiotropic functions of the immunoproteasome are during bacterial sepsis, and how the immunoproteasome shapes the proteomes and transcriptomes of macrophages. These studies will include using triple-knockout mice for all three regulatory immunoproteasome subunits (PSMB8/9/10). (3) We will study how the MAVS pathway amplifies the harmful molecular sequelae of bacterial sepsis focusing on phagocyte extracellular traps (NETs/METs), IL-6/IL-12 cytokines, septic coagulopathy and immunosuppression; which all contribute to tissue injury, organ dysfunction and sepsis lethality. In particular, we will consider a novel role of the immunoproteasome in subcellular protein degradation for facilitating extracellular trap formation. In summary, elucidating the previously unsuspected involvement of the MAVS pathway during bacterial infection will provide novel and important information and may add critical insights for guiding future efforts to develop effective therapies for sepsis.

脓毒症是微生物感染的常见且危及生命的并发症。估计超过美国每年发生 750,000 例败血症病例，尽管死亡率仍维持在 20-50% 左右重症监护支持的最新进展。在目前尚无 FDA 批准的药理化合物的情况下，仍然迫切需要对潜在的细胞和分子进行完整的表征败血症的机制。宿主反应失调是病理生理学过程中的一个突出特征细菌性败血症，但其整合分子途径的微妙平衡似乎并不完全清楚。线粒体抗病毒信号蛋白 (MAVS) 是线粒体外膜中的接头分子并且在专业吞噬细胞中高度表达。 MAVS 由细胞质 RNA 解旋酶 RIG- 激活 I 和 MDA5，并提供针对病毒感染的保护。令人惊讶的是，我们的初步研究结果表明小鼠中 MAVS 或 RIG-I/MDA5 的缺失赋予了对死亡的巨大抵抗力并调节吞噬细胞转录组、免疫蛋白酶体、细胞外陷阱、IL-6/IL-12 细胞因子和凝血过程多种微生物细菌性败血症。细菌 RNA 是一种与活力相关的病原体模式（“vita-PAMP”）由巨噬细胞中的 MAVS 通路感知。总之，这些发现表明了有害的角色逆转细菌败血症期间的 MAVS 与病毒感染期间的保护性 MAVS 通路功能相反。检验我们的中心假设，即 MAVS 信号传导提供了阻碍有利脓毒症的致命开关成果，我们将追求 3 个具体目标：（1）我们将研究基因表达、激活机制， MAVS 在专业吞噬细胞（巨噬细胞、中性粒细胞）中的信号事件和功能作用多种微生物细菌性败血症。在这些研究中，MAVS 基因完全或有条件缺失的小鼠，或提供 RIG-I/MDA5 传感器。 MAVS 缺陷的人类巨噬细胞将使用 CRISPR-Cas9 生成。 (2)我们将确定MAVS诱导的转录因子如何促进免疫蛋白酶体的基因表达亚基，免疫蛋白酶体在细菌性脓毒症期间的多效性功能是什么，以及如何免疫蛋白酶体塑造巨噬细胞的蛋白质组和转录组。这些研究将包括使用所有三个调节性免疫蛋白酶体亚基的三重敲除小鼠（PSMB8/9/10）。 (3)我们将研究如何 MAVS 通路放大了针对吞噬细胞的细菌性败血症的有害分子后遗症细胞外陷阱 (NETs/METs)、IL-6/IL-12 细胞因子、脓毒性凝血病和免疫抑制；其中所有导致组织损伤、器官功能障碍和败血症致死。特别是，我们将考虑一个新颖的角色亚细胞蛋白质降解中的免疫蛋白酶体促进细胞外陷阱的形成。总之，阐明以前未曾怀疑的 MAVS 通路在细菌感染过程中的参与将提供新颖且重要的信息，可能会增加重要的见解，以指导未来开发有效的工作脓毒症的治疗方法。