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Dissecting novel mechanisms of dengue virus NS1-induced vascular leak

剖析登革热病毒 NS1 诱导血管渗漏的新机制

基本信息

批准号：
9221261
负责人：
Eva Harris
金额：
$ 38.27万
依托单位：
UNIVERSITY OF CALIFORNIA BERKELEY
依托单位国家：
美国
项目类别：
财政年份：
2016
资助国家：
美国
起止时间：
2016-02-15 至 2021-01-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9221261
关键词：
Acute Affect Amino Acids Antibodies Area Binding Biological Blood Blood Vessels Cell Culture Techniques Cell Extracts Cells Chimera organism Culicidae Dengue Dengue Infection Dengue Vaccine Dengue Virus Disease Dose Endothelial Cells Endothelium Extravasation Flavivirus Functional disorder Glycocalyx Human Immune Immunization In Vitro Infection Inflammatory Injection of therapeutic agent Intercellular Junctions Investigation Laboratories Lead Lipids Mediating Modeling Molecular Monoclonal Antibodies Mus Pathogenesis Pathogenicity Pathway interactions Patients Permeability Physiological Plasma Polysaccharides Process Proteins Research Role Serotyping Serum Severity of illness Shock Signal Pathway Site Structure Surface Symptoms Syndrome T-Lymphocyte Therapeutic Vaccination Vascular Permeabilities Viral Proteins Virus West Nile virus cross reactivity cytokine defined contribution glycosylation improved in vitro Model in vivo in vivo Model inhibitor/antagonist monolayer mouse model mutant novel public health relevance response virus pathogenesis

项目摘要

DESCRIPTION (provided by applicant): Determining novel mechanisms of dengue virus NS1-induced vascular leak. The four dengue virus serotypes (DENV1-4) are mosquito-borne flaviviruses that cause ~100 million cases of dengue annually worldwide. Severe disease is thought to result from immunopathogenic processes involving serotype cross-reactive antibodies and T cells that induce vasoactive cytokines, which cause endothelial disruption and vascular leakage leading to shock. To date, no viral proteins have been directly implicated in triggering endothelial permeability. DENV non-structural protein 1 (NS1) is secreted by infected cells and circulates in patients' blood during acute infection, and high levels of sNS1 are associated with severe disease. We have recently shown that injection of mice with DENV NS1 protein in the absence of virus induces both vascular leak and an increase in key inflammatory cytokines, while simultaneous administration of NS1 with a sublethal dose of DENV2 results in a lethal vascular leak syndrome. We have also demonstrated that NS1 from DENV1-4, but not from the related flavivirus West Nile virus (WNV), triggers endothelial barrier dysfunction and increased permeability of human endothelial cell monolayers in vitro. Finally, we found that NS1 vaccination and anti-NS1 antibodies can protect against NS1-mediated pathogenesis and endothelial permeability. These findings add an important and previously-overlooked component to the causes of dengue vascular leak, identify a new potential target for anti-dengue therapeutics, and support inclusion of NS1 in dengue vaccines. Here we propose to use the in vitro and in vivo models of DENV pathogenesis we have established to define the contributions of secreted NS1 protein to dengue pathogenesis. Our in vitro model allows us to examine the mechanism(s) of how NS1 leads to loss of endothelial barrier integrity, a key component of DENV pathogenesis resulting in vascular leak. Our murine model of DENV infection recapitulates vascular leak symptoms seen in humans, and we have developed both systemic and localized models of vascular permeability. In Aim 1, we will identify endothelial cell-specific responses to DENV NS1 and define the mechanism of NS1-induced endothelial permeability both in vitro and in vivo. In Aim 2, we will define the cytokine-dependent effector mechanisms activated by DENV NS1 and determine their relative contribution to NS1-dependent increases in vascular permeability in vivo and ex vivo. In Aim 3, using a structure/function approach with DENV/WNV NS1 chimeras and site-specific mutants, together with a battery of genetically deficient mice and inhibitors of specific host signaling pathways, we will determine the molecular determinants of NS1 that are responsible for pathogenic functions in vitro and in vivo. Overall, these studies will advance a critical new area of investigation regarding the novel functions of DENV NS1 in inducing vascular leak and define the molecular determinants of NS1-induced pathogenesis, directly contributing to improving our understanding of severe dengue disease and opening new pathways for treatment.