Abstract
Dengue hemorrhagic fever/dengue shock syndrome (DHF/DSS) is a severe pathological manifestation of dengue virus (DENV) infection. Enhanced production of cytokines in dengue patients is proposed to induce endothelial barrier instability resulting in increased vascular leakage. Tumor necrosis factor (TNF)-α is an inflammatory cytokine that activates endothelial cells and enhances vascular permeability and plasma leakage in DHF/DSS. The present study investigated the in vitro effect of TNF-α and DENV infection on the expression of adherence junction proteins, tight junction proteins, and membrane integrity of human endothelial cell lines. Immunofluorescence staining and western blot analysis demonstrated platelet endothelial cell adhesion molecule-1 (PECAM-1) reorganization and decreased levels of the tight junction protein occludin in human endothelial cells treated with TNF-α and DENV, compared to mock, DENV, or TNF-α-treated cells. Permeability assessed by FITC-dextran as a transport molecule was increased and correlated with the unusual reorganization of PECAM-1. The altered distribution of PECAM-1 and low occludin protein levels in human endothelial cells treated with TNF-α and DENV correlated with increased permeability. In conclusion, the synergistic effect of TNF-α and DENV induced permeability changes in endothelial cells. These results contribute to the understanding of the mechanisms underlying enhanced vascular permeability in DENV infection.
