Host Cell JAK-STAT Activation and Pathogenesis of Spotted Fever Rickettsioses

宿主细胞 JAK-STAT 激活和斑点热立克次体病的发病机制

• 批准号: 8524206
• 负责人: Sanjeev K. Sahni
• 金额: $ 38.25万
• 依托单位: UNIVERSITY OF TEXAS MED BR GALVESTON
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-08-20 至 2014-08-19
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8524206
• 关键词: Activated Natural Killer Cell; Adhesives; Adult Respiratory Distress Syndrome; Anti-Bacterial Agents; Antibodies; Antiviral Agents; Binding; Biological; Blood Vessels; Boutonneuse Fever; Cardiac Output; Case Fatality Rates; Cells; Cellular biology; Cerebral Edema; Conditioned Culture Media; DNA Binding; Data; Development; Disease; Encephalitis; Endothelial Cells; Endothelium; Fever; Functional disorder; Genes; Gram-Negative Bacteria; Growth; Host Defense; Host Defense Mechanism; Human; IFNAR1 gene; Immune response; In Vitro; Infection; Inflammatory; Interferons; Janus kinase; Knowledge; Lipopolysaccharides; Lung; Mediating; Methods; Microbe; Microscopy; Modeling; Molecular Genetics; Morbidity - disease rate; Mouse Strains; Mus; Natural Immunity; Nuclear Translocation; Pathogenesis; Patients; Pattern; Phenotype; Phosphorylation; Phylogenetic Analysis; Play; Proteins; Proteobacteria; Proteomics; Publishing; Pulmonary Edema; RNA Interference; Rickettsia; Rickettsia Infections; Rickettsia rickettsii; Rocky Mountain Spotted Fever; Role; STAT protein; STAT1 gene; STAT3 gene; Scourge; Second Messenger Systems; Severities; Signal Pathway; Signal Transduction; Spottings; TLR4 gene; Testing; Therapeutic; Tick-Borne Diseases; Tissues; Transcriptional Activation; Tropism; Vascular Endothelium; Vascular Permeabilities; Vasculitis; autocrine; base; cytokine; human IFITM1 protein; human disease; improved; in vivo; innovation; insight; microbial; mortality; mouse model; novel; novel therapeutics; paracrine; pathogen; pathogenic bacteria; receptor; response; second messenger; trait; vascular inflammation

DESCRIPTION (provided by applicant): Rickettsia rickettsii and R. conorii are Gram-negative, obligate intracellular a-proteobacteria known to cause Rocky Mountain spotted fever (RMSF) and Mediterranean SF in humans. A unique trait of pathogenic rickettsiae is the tropism for microvascular endothelium of the blood vessels, which results in disseminated endothelial infection, vascular inflammation, and compromised vascular permeability. Activation of otherwise quiescent endothelium in response to rickettsial invasion is characterized by acquisition of prothrombotic, procoagulant and proinflammatory phenotypes, manifesting as 'rickettsial vasculitis'. Although endothelial activation typically involves input from multiple upstream mechanisms, including Janus Kinase-Signal Transducer and Activator of Transcription (JAK-STAT) proteins, the potential contributions of this critically important signaling pathway, which is typically involved in antiviral host defense, in rickettsial interactios with the host cell are completely unknown. Published as well as preliminary in vitro and in vivo evidence from our recent findings suggests: i) early STAT3 and late STAT1 activation in human microvascular endothelial cells (ECs) infected with SF rickettsiae; ii) ability of 'conditioned medium' from infected cells to activate STAT1 in na¿ve ECs through IFN-b; iii) increased expression of Interferon-Stimulated Gene encoding protein of 15 kDa (ISG15) dependent on IFN-b and STAT1; and iv) anti-bacterial activities of IFN-b, STAT1 and ISG15 against rickettsiae. These novel findings are the basis of three independent albeit mechanistically overlapping specific aims. First, we will identify receptor-mediated and intracytoplasmic signaling mechanisms and consequences of JAK-STAT activation during infection of cultured human and murine ECs with spotted fever rickettsiae. Because ISG15 not only plays an important role in innate immunity, but can also bind to other cellular proteins and modulate their functions via ISGylation, the second aim will determine its role in host defense mechanisms against pathogenic rickettsiae. Specifically, we will identify and analyze the functions of ISGylated proteins in infected endothelium and determine whether cytokine-like activity of secreted ISG15 activates Natural Killer cell-mediated host defense. Finally, we will define the potential roles of IFN-b, STAT1, and ISG15 as critical determinants of host defense exploiting established as well as novel murine models of infection mimicking human disease and mice lacking IFNAR, STAT1, and ISG15 as the host. We will employ contemporary, cutting edge methods of cell biology, microscopy, molecular genetics, and proteomics to reveal unique insights into mechanisms underlying host defense vis-¿-vis pathogenesis. Since rickettsioses are now re-emerging globally, comprehensive understanding of the pathogen interactions with the target host cell will aid in the identification of innovative therapeutic strategies to alter te course of debilitating rickettsial infections in favor of the host.

描述（由适用提供）：立克人士立克西氏菌和R. conoriii是革兰氏阴性的，强性的细胞内A-蛋白细菌，已知会引起岩石山斑点发烧（RMSF）和人类的地中海SF。致病性人力体的独特特征是血管微血管森植物的热带主义，这导致了传播的触地感染，血管感染和造成的血管渗透性。虽然内皮激活的激活通常涉及多种上游机制的输入，其中包括Janus激酶信号传感器和转录（JAK-STAT）蛋白的激活，这是这种非常重要的信号通路的潜在贡献，通常与抗活性宿主防御，Intickettsial Intersial与宿主单元完全相互作用。从我们最近的发现中发表的以及在体外和体外证据中发表的证据表明：i）在感染SF Rickettsiae的人类微血管内皮细胞（ECS）中STAT3早期和晚期STAT1激活； ii）从感染细胞中“条件培养基”通过IFN-B激活NA¿EC中Stat1的能力； iii）根据IFN-B和STAT1的15 kDa（ISG15）的干扰素刺激的基因的表达增加； IV）IFN-B，STAT1和ISG15的抗菌活性针对人力车。这些新颖的发现是三个独立的特定目的的三个独立重叠的基础。首先，我们将确定受体介导的和胞质内信号传导机制以及jak-STAT激活在培养的人和鼠ECS中带有斑点发烧的人力体的感染期间的后果。因为ISG15不仅在先天免疫中起着重要作用，而且还可以与其他细胞蛋白结合并通过ISGyLation调节其功能，因此第二个目标将决定其在针对致病性Rickettsiae的宿主防御机制中的作用。具体而言，我们将识别和分析Isgylated蛋白在感染的内皮中的功能，并确定分泌的ISG15的细胞因子样活性是否激活了天然杀伤细胞介导的宿主防御。最后，我们将将IFN-B，STAT1和ISG15的潜在作用定义为剥削已建立的宿主防御的关键决定者，以及模仿人类疾病的新型鼠模型，而缺乏IFNAR，STAT1和ISG15的小鼠作为宿主。我们将采用当代的细胞生物学，显微镜，分子遗传学和蛋白质组学的最先进方法来揭示对宿主防御性抗Vis -vis发病机理的机制的独特见解。由于现在在全球范围内重新出现，对与目标宿主细胞的病原体相互作用的全面理解将有助于鉴定创新的治疗策略，以改变使人力体感染使人衰弱的疾病，以支持宿主。