Role reversal of MAVS in bacterial sepsis

MAVS 在细菌性脓毒症中的作用逆转

• 批准号: 10191010
• 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
• 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/10191010
• 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; Family; Functional disorder; Future; Gene Deletion; Gene Expression; Genes; Histones; Human; Immune; Immune response; Immunosuppression; Infection; Interleukin-12; Interleukin-6; Knockout Mice; Life; Microbe; Mitochondria; Molecular; Molecular Target; Morbidity - disease rate; Mouse Protein; Multiple Organ Failure; 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; 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; tissue injury; transcription factor; transcriptome; transcriptome sequencing; translational study

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.

脓毒症是一种常见的、危及生命的微生物感染并发症。据估计，超过 美国每年发生75万例脓毒症病例，死亡率保持在20%-50%左右，尽管 重症监护支持的最新进展。在目前没有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。 败血症的发病机制。寄主反应失调是肺炎的病理生理过程中的一个显著特征。 细菌败血症，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)是线粒体膜外膜的一种适配分子。 并在专业吞噬细胞中高度表达。MAV由细胞质RNA解旋酶RIG-1激活。 I和MDA5，并提供对病毒感染的保护。令人惊讶的是，我们的初步发现表明 小鼠体内MAV或RIG-I/MDA5的缺失对死亡具有巨大的抵抗力并调节吞噬细胞 转录本、免疫蛋白酶体、细胞外陷阱、IL-6/IL-12细胞因子与凝血 多菌细菌性败血症。细菌RNA是一种与生存相关的病原体模式(‘vita-PAMPs’) 通过巨噬细胞中的MAVS途径感受到。综上所述，这些发现表明， 细菌败血症期间的MAV，而不是病毒感染期间的保护性MAV途径。 为了验证我们的中心假设，即MAVS信号为阻止有利的脓毒症提供了致命的开关 结果，我们将追求3个具体目标：(1)研究基因表达，激活机制， MAV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 多菌细菌性败血症。在这些研究中，MAV基因完全或有条件缺失的小鼠，或 RIG-I/MDA5传感器可用。使用CRISPR-Cas9将产生MAVS缺陷的人巨噬细胞。 (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败血症中的多功能是什么，以及如何 免疫蛋白酶体塑造巨噬细胞的蛋白质组和转录体。这些研究将包括使用 所有三个调节性免疫蛋白酶体亚单位的三重敲除小鼠(PSMB8/9/10)。(三)我们会研究如何 MAVS途径放大了以吞噬细胞为中心的细菌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、败血症凝血障碍和免疫抑制； 导致组织损伤、器官功能障碍和脓毒症致命性。特别是，我们将考虑一个新的角色 免疫蛋白酶体在亚细胞蛋白降解中促进细胞外TRAP的形成。总而言之， 阐明在细菌感染过程中先前未被怀疑的MAVS通路的参与将提供 新的和重要的信息，并可能为指导未来的努力制定有效的 败血症的治疗方法。