Lipid Raft- and Src Family Kinase-Dependent Entry of Coxsackievirus B into Human Placental Trophoblasts

Abstract

bMaternal-fetal transmission of group B coxsackieviruses (CVB) during pregnancy has been associated with a number of diverse pathological outcomes, including hydrops fetalis, fetal myocarditis, meningoencephalitis, neurodevelopmental delays, congenital skin lesions, miscarriage, and/or stillbirth. Throughout pregnancy, the placenta forms a critical antimicrobial protective barrier at the maternal-fetal interface. Despite the severity of diseases accompanying fetal CVB infections, little is known regarding the strategies used by CVB to gain entry into placental trophoblasts. Here we used both a trophoblast cell line and primary human trophoblasts to demonstrate the mechanism by which CVB gains entry into polarized placental trophoblasts. Our studies revealed that the kinetics of CVB entry into placental trophoblasts are similar to those previously described for polarized intestinal epithelial cells. Likewise, CVB entry into placental trophoblasts requires decay-accelerating factor (DAF) binding and involves relocalization of the virus from the apical surface to intercellular tight junctions. In contrast, we have identified a divergent mechanism for CVB entry into polarized trophoblasts that is clathrin, caveolin-1, and dynamin II independent but requires intact lipid rafts. In addition, we found that members of the Src family of tyrosine kinases were required for CVB entry. Our studies highlight the complexity of viral entry into human placental trophoblasts and may serve as a model for mechanisms used by diverse pathogens to penetrate the placental barrier.

Type III interferon signaling restricts Enterovirus 71 infection of goblet cells

“…Indeed, follow up studies confirmed that EV71 vRNA was exclusively localized to mucin-2 (MUC2)-positive goblet cells ( Figure 4B, 4C ). As an additional confirmation for the goblet cell specificity of EV71 infection, we also performed immunofluorescence microscopy for VP1 using an immunostaining technique that distinguishes between VP1 localized on the extracellular surface and VP1 localized intracellularly 24 . These studies confirmed the presence of intracellular VP1 only in cells exhibiting goblet cell morphology ( Figure 4D ).…”

“…Experiments were performed with EV-71 (1095), or E11 (Gregory) that were expanded as described previously 41 . In some cases, experiments were performed with light-sensitive neutral-red viral particles, which was generated as described previously 24 . Briefly, EV71 was propagated in the presence of 10µg/mL of neutral red in the semi-dark and was subsequently purified in semi-dark conditions by ultracentrifugation over a sucrose cushion, as described 41 .…”

RIP3 Regulates Autophagy and Promotes Coxsackievirus B3 Infection of Intestinal Epithelial Cells

“…Neutral red-labeled CVB3-RD was prepared as previously described (Delorme-Axford et al, 2013b). For time courses of infection in HT29 cells, CVB was pre-adsorbed to cells for 1 hr at 16°C to synchronize infection.…”

Blood Groups in Infection and Host Susceptibility

“…Although the primary receptor for CVB is CAR, a tight-junction protein, CD55 is recognized as a coreceptor by some coxsackie B virus serotypes (CVB1, CVB3, and CVB5) (646). In polarized intestinal and trophoblastic epithelial cells, CVB binds CD55 on apical membranes and is then transported toward the tight junctions to bind CAR, followed by caveolindependent endocytosis (647,648). Both membrane trafficking and invasion are dependent on lipid rafts and can be disrupted by methyl-␤-cyclodextrin and simvastatin.…”

“…Both membrane trafficking and invasion are dependent on lipid rafts and can be disrupted by methyl-␤-cyclodextrin and simvastatin. Like Dr adhesins, virus uptake involves signaling through raft-associated Src kinases (648). In cell cultures, CVB infection can be blocked by soluble CD55 and CD55 antibodies (645,646).…”