DENV NS1 and MMP-9 cooperate to induce vascular leakage by altering endothelial cell adhesion and tight junction
Dengue virus (DENV) is a mosquito-borne pathogen that causes a spectrum of diseases including life-threatening dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS). Vascular leakage is a common clinical crisis in DHF/DSS patients which is closely associated with increased endothelial permeability. The presence of vascular leakage causes hypotension, circulatory failure or disseminated intravascular coagulation as the disease progresses, which can lead to death under such conditions. However, the mechanisms by which DENV infection caused the vascular leakage are not fully understood. This study reveals a distinct mechanism by which DENV induces endothelial permeability and vascular leakage in human endothelial cells and mice tissues. We initially show that DENV2 promotes the matrix metalloproteinase-9 (MMP-9) expression and secretion in DHF patient serum, peripheral blood mononuclear cells (PBMCs) and macrophages, and further reveal that DENV non-structural protein 1 (NS1) induces MMP-9 expression through activating the nuclear factor {kappa}B (NF-{kappa}B) signaling pathway. Additionally, NS1 inhibits TIMP-1 expression to facilitates the MMP-9 enzymatic activity which alters the adhesion and tight junctions and vascular leakage in human endothelial cells and mouse tissues. Moreover, NS1 recruits MMP-9 to interact with {beta}-catenin and Zona occludins protein-1/2 to degrade the important adhesion and tight junction proteins, thereby inducing endothelial hyperpermeability and vascular leakage in human endothelial cells and mouse tissues. Thus, we reveal that DENV NS1 and MMP-9 cooperatively induce vascular leakage by impairing endothelial cell adhesion and tight junction, and suggest that MMP-9 may serve as a potential target for the treatment of hypovolemia in DSS/DHF patients. Author SummaryDENV is the most common mosquito-transmitted viral pathogen in humans. In general, DENV-infected patients are either asymptomatic or have flu-like symptoms with fever and rash. However, in severe cases of DENV infection, the disease may progress to dengue hemorrhagic fever (DHF) or dengue shock syndrome (DSS), the leading causes of morbidity and mortality in school-age children in tropical and subtropical regions. DENV-induced vascular leakage is characterized by enhanced vascular permeability without morphological damage to the capillary endothelium. We found that a distinct mechanism of DENV NS1 and MMP-9 cooperatively induce vascular leakage is the main reason leading to death in severe dengue patients. Also, NS1 recruits MMP-9 to degrade {beta}-catenin, ZO-1, ZO-2 to intervene endothelial hyperpermeability in human endothelial cells and mouse vascular. Finally, we reveal that DENV activating NF-{kappa}B signaling pathway induces MMP-9 expression, in patients, mice, PBMC and macrophages though the viral NS1 protein. This study would provide new in signs into the pathogenesis caused by DENV infection, and suggest that MMP-9 may acts as a drug target for the prevention and treatment of DENV-associated diseases.