Sulfated Escherichia coli K5 Polysaccharide Derivatives Inhibit Dengue Virus Infection of Human Microvascular Endothelial Cells by Interacting with the Viral Envelope Protein E Domain III

Peter Vervaeke,Sam Noppen,Marijke Alen,Sandra Liekens,Pasqua Oreste,Dominique Schols,Bruce W Banfield

doi:10.1371/journal.pone.0074035

Abstract

Dengue virus (DENV) is an emerging mosquito-borne pathogen that causes cytokine-mediated alterations in the barrier function of the microvascular endothelium, leading to dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS). We observed that DENV (serotype 2) productively infects primary (HMVEC-d) and immortalized (HMEC-1) human dermal microvascular endothelial cells, despite the absence of well-described DENV receptors, such as dendritic cell-specific intercellular adhesion molecule-3-grabbing non-integrin (DC-SIGN) or the mannose receptor on the cell surface. However, heparan sulfate proteoglycans (HSPGs) were highly expressed on these cells and pre-treatment of HMEC-1 cells with heparinase II or with glycosaminoglycans reduced DENV infectivity up to 90%, suggesting that DENV uses HSPGs as attachment receptor on microvascular endothelial cells. Sulfated Escherichia coli K5 derivatives, which are structurally similar to heparin/heparan sulfate but lack anticoagulant activity, were able to block DENV infection of HMEC-1 and HMVEC-d cells in the nanomolar range. The highly sulfated K5-OS(H) and K5-N,OS(H) inhibited virus attachment and subsequent entry into microvascular endothelial cells by interacting with the viral envelope (E) protein, as shown by surface plasmon resonance (SPR) analysis using the receptor-binding domain III of the E protein.

Highlights

Dengue virus (DENV) is a mosquito-borne flavivirus that infects 50–100 million people each year, resulting in 500,000 hospitalizations and 25,000 deaths [1,2]
Since DENV-induced plasma leakage occurs at the level of the microvasculature [37,38] we studied DENV infection in primary human dermal microvascular endothelial cells (HMVEC-d) and the microvascular cell line HMEC-1 [39]
The microvascular endothelium forms the primary fluid barrier of the capillaries, but the extent to which the endothelial cells contribute to increased capillary permeability in dengue hemorrhagic fever (DHF)/dengue shock syndrome (DSS) is not well understood [37,38]

Summary

Introduction

Dengue virus (DENV) is a mosquito-borne flavivirus that infects 50–100 million people each year, resulting in 500,000 hospitalizations and 25,000 deaths [1,2]. We found that DENV infection of microvascular endothelial cells is mediated by HSPGs. we investigated whether heparin analogues display anti-DENV activity in these cells. We demonstrate that the highly sulfated K5-OS(H) and K5-N,OS(H) inhibit DENV attachment and entry in microvascular endothelial cells by interacting with domain III of the viral envelope protein, indicating that these agents may represent a promising new class of anti-DENV agents.

Results

Conclusion