Caveolae-mediated albumin transcytosis is enhanced in dengue-infected human endothelial cells: A model of vascular leakage in dengue hemorrhagic fever.

Chanettee Chanthick,Sa-Nga Pattanakitsakul,Visith Thongboonkerd,Rattanaporn Kiatbumrung,Rattiyaporn Kanlaya

doi:10.1038/srep31855

Chanettee Chanthick, Sa-Nga Pattanakitsakul + Show 3 more

Open Access

https://doi.org/10.1038/srep31855

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Journal: Scientific Reports	Publication Date: Aug 22, 2016
Citations: 22	License type: CC BY 4.0

Affiliation: Siriraj Hospital, Mahidol University

Abstract

Vascular leakage is a life-threatening complication of dengue virus (DENV) infection. Previously, association between “paracellular” endothelial hyperpermeability and plasma leakage had been extensively investigated. However, whether “transcellular” endothelial leakage is involved in dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS) remained unknown. We thus investigated effects of DENV (serotype 2) infection on transcellular transport of albumin, the main oncotic plasma protein, through human endothelial cell monolayer by Western blotting, immunofluorescence staining, fluorescence imaging, and fluorometry. The data showed that Alexa488-conjugated bovine serum albumin (Alexa488-BSA) was detectable inside DENV2-infected cells and its level was progressively increased during 48-h post-infection. While paracellular transport could be excluded using FITC-conjugated dextran, Alexa488-BSA was progressively increased and decreased in lower and upper chambers of Transwell, respectively. Pretreatment with nystatin, an inhibitor of caveolae-dependent endocytic pathway, significantly decreased albumin internalization into the DENV2-infected cells, whereas inhibitors of other endocytic pathways showed no significant effects. Co-localization of the internalized Alexa488-BSA and caveolin-1 was also observed. Our findings indicate that DENV infection enhances caveolae-mediated albumin transcytosis through human endothelial cells that may ultimately induce plasma leakage from intravascular compartment. Further elucidation of this model in vivo may lead to effective prevention and better therapeutic outcome of DHF/DSS.

Highlights

Vascular wall, as the target or affected tissue for plasma leakage, is composed of endothelial cell monolayer that acts as a semi-permeable barrier
Transcellular albumin transport or albumin transcytosis is a common feature of endothelial cell that serves as a key mechanism to regulate basal vascular permeability (BVP) under normal condition[12,13,14]
Our concern was that the degree of DENV serotype 2 (DENV2) infection, represented by multiplicity of infection (MOI) used for DENV2 challenge and post-infection incubation period, should not induce obvious cytotoxicity that increased cell death

Summary

Introduction

As the target or affected tissue for plasma leakage, is composed of endothelial cell monolayer that acts as a semi-permeable barrier. Endothelial cell has an ability to regulate its paracellular (through intercellular junctions) and transcellular (through endothelial cell) transports of fluid, solutes, and proteins[6,7]. Association between paracellular endothelial hyperpermeability and plasma leakage has been extensively investigated in several diseases, including DENV infection[8,9,10,11]. In acute lung injury, the increase of caveolae-mediated transendothelial albumin transport is initiated by adherence of fMLP-activated neutrophils to vascular wall, resulting to fluid imbalance and excessive extravascular fluid accumulation[16]. The present study aimed to address effects of DENV infection on albumin transcytosis in human endothelial (EA.hy926) cells that could be linked to the pathogenic mechanisms of plasma leakage in DHF/DSS

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Conclusion