Differential Expression of PDGF Receptor-\u03b1 in Human Placental Trophoblasts Leads to Different Entry Pathways by Human Cytomegalovirus Strains

William D. Rawlinson,Wendy J. van Zuylen,Stuart T. Hamilton,Zin Naing,Gillian M. Scott

doi:10.1038/s41598-020-57471-3

William D. Rawlinson, Wendy J. van Zuylen + Show 3 more

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https://doi.org/10.1038/s41598-020-57471-3

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Abstract

Human cytomegalovirus (CMV) is the leading non-genetic cause of fetal malformation in developed countries. CMV placental infection is a pre-requisite for materno-fetal transmission of virus, and fetal infection. We investigated the roles of the viral pentameric complex gH/gL/pUL128-pUL131A, and cellular platelet-derived growth factor receptor-α (PDGFRα) for CMV infection in first trimester extravillous-derived (SGHPL-4) and villous-derived (HTR-8/SVneo) trophoblast cells. Infection with four CMV clinical and laboratory strains (Merlin, TB40E, Towne, AD169), and Merlin deletion mutants of UL128-, UL130-, and UL131A-genes, showed a cell type-dependent requirement of the viral pentameric complex for infection of trophoblast cells. The viral pentameric complex was essential for infection of villous trophoblasts, but non-essential for extravillous trophoblasts. Blocking of PDGFRα in extravillous trophoblasts, which naturally express PDGFRα, inhibited entry of pentameric complex-deficient CMV strains, but not the entry of pentameric positive CMV strains. Transient expression of PDGFRα in villous trophoblasts, which are naturally deficient in PDGFRα, promoted the entry of CMV strains lacking gH/gL/pUL128-pUL131A, but had no effect on entry of pentameric positive CMV strains. These results suggest PDGFRα is an important cell receptor for entry of CMV mutant strains lacking gH/gL/pUL128-pUL131A complexes in some placental cells, suggesting these entry pathways could be potential antiviral targets.

Highlights

Www.nature.com/scientificreports early and late gestation placentae[12,13]
Infection efficiencies of CMV strains in HTR-8/SVneo (B) and SGHPL-4 (C) cells are presented as percentage of viral IE1p72 and early pUL44 (IE/E)-positive nuclei in randomly selected fields (n = 15 from three independent experiments)
Infection with wild-type Merlin in SGHPL-4 trophoblasts was significantly more efficient than the Merlin UL128-UL131A-deletion mutant counterparts (21.3% versus 15.8% IE/E-positive cells, P = 0.042). These data indicate that the glycoprotein H (gH)/gL/pUL128-pUL131A complex is essential for infection of villous HTR-8/SVneo trophoblasts, and the pentameric complex contributes to efficient infection of extravillous SGHPL-4 trophoblasts, it is not essential for infection of these cells

Summary

Introduction

Www.nature.com/scientificreports early and late gestation placentae[12,13]. Productive CMV replication has been demonstrated in ex vivo villous explant models, where CMV infection of villous cytotrophoblasts precedes infection of other placental cell types[14,15]. The platelet-derived growth factor receptor-α (PDGFRα), epidermal growth factor receptor (EGFR), integrins, annexin II, dendritic cell-specific ICAM-grabbing nonintegrin, neurophilin-2 and OR14I1 have been proposed as CMV receptors for infection of different cell types including fibroblasts, epithelial cells, endothelial cells, lymphocytes, and dendritic cells[45,46,47,48,49,50,51,52,53] Several of these receptors (PDGFRα, EGFR, integrin β1/αVβ3, annexin II) interact with gB, gH, or gO and this has been shown to facilitate viral entry and activation of cellular signalling pathways[45,46,48,54,55,56]. We demonstrated that CMV uses different entry pathways, involving at least the viral pentameric complex and cellular PDGFRα receptor for entry into placental trophoblasts

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