Evaluation of DENV-Induced Endothelial Cell Permeability by Measurements of Transendothelial Electrical Resistance (TEER) and Extravasation of Proteins and Virus

This chapter will discuss reliable and relatively easy and fast strategies to evaluate the integrity of endothelial cell monolayers when infected by dengue virus (DENV). Human brain microvascular endothelial cells (HBMEC) were exploited here as general model of vessel wall core, but it may also be used as an in vitro simplified model of blood brain barrier (BBB). The integrity of endothelial cells monolayer can be inferred using a transwell culture system by: (1) measuring transendothelial electrical resistance (TEER) using a Voltohmmeter; (2) analyzing the monolayer permeability to fluorescent-conjugated proteins and fluorimetric assay; (3) investigating virus extravasation by quantitative RT-PCR and plaque conventional assay. The rational to use those strategies is that vascular alterations are often observed during dengue infection, being associated to disease severity. The vasculature core consists of a barrier of endothelial cells, which are tightly adhered by the expression of adhesion molecules and tight junctions. This structure must be preserved in order to control the flux of cells and metabolites from the circulation to the tissues and to maintain vascular homeostasis. Therefore, experimental assays that allow evaluation of endothelial integrity can be useful platforms to further understand disease pathogenesis and screen pharmaceutical interventions to control vascular disturbance.