JUNIN VIRUS INDUCED ALTERATIONS OF HUMAN ENDOTHELIAL CELL ADHERENS JUNCTIONS

Heather Lander¹, A.M. Grant¹, C.J. Peters, M.D. ^1,2

¹Departments of Pathology and ²Microbiology and Immunology, UTMB

Background: Junin Virus (JV) is the etiologic agent of Argentine hemorrhagic fever, a classic arenaviral hemorrhagic fever exhibiting increased vascular permeability, the mechanisms of which are still unclear. It is widely accepted that mediators produced by infected inflammatory cells contribute significantly to increased vascular permeability during arenaviral hemorrhagic fevers, but endothelial cells are also targeted, to varying degrees; thus, direct infection may play a crucial role in pathogenesis. In endothelial cells, adherens junctions are well established to modulate permeability and we hypothesize that organization of these junctions is disrupted during JV infection. Therefore, our Objective: is to determine the direct effects of JV infection on the adherens junctions of human umbilical vein endothelial cells (HUVEC). Methods: Using coimmunoprecipitations, western blotting, electric cell-substrate impedance sensing (ECIS) and confocal microscopy, we investigated changes in adherens junction protein complexes, protein expression levels, protein phosphorylation states, and electrical resistance during infection with JV. Results: We show that early during JV infection and in the absence of visible cytopathology: VE-cadherin/β-catenin complexes are decreased; β-catenin expression levels do not change; VE-cadherin and p120 staining is reduced; tyrosine phosphorylation of several adherens junction proteins is altered and electrical resistance of the monolayer is decreased. Conclusion: Our data are the first evidence that endothelial cell responses to direct JV infection contribute to disorganization of endothelial cell adherens junctions which could play a major role in the pathogenesis of JV and perhaps other hemorrhagic fever viruses. Supported by the Department of Pathology and NIH Biodefense Training T32 AI060549.