Human Cytomegalovirus Modulates Expression of Noncanonical Wnt Receptor ROR2 To Alter Trophoblast Migration

Abstract

Maternal primary cytomegalovirus (CMV) infection, reactivation, or reinfection with a different viral strain may cause fetal injury and adverse pregnancy outcomes. Increasing evidence indicates that fetal injury results not only from direct viral cytopathic damage to the CMV-infected fetus but also from indirect effects through placental infection and dysfunction. CMV alters Wingless (Wnt) signaling, an essential cellular pathway involved in placentation, as evidenced by reduced transcription of canonical Wnt target genes and decreased Wnt3a-induced trophoblast migration. Whether CMV affects the noncanonical Wnt signaling pathway has been unclear. This study demonstrates for the first time that CMV infection inhibits Wnt5a-stimulated migration of human SGHPL-4 trophoblasts and that inhibition of the pathway restores normal migration of CMV-infected cells. Western blot and real-time PCR analyses show increased expression of noncanonical Wnt receptor ROR2 in CMV-infected trophoblasts. Mimicking the CMV-induced ROR2 protein expression via ectopic expression inhibited Wnt5a-induced trophoblast migration and reduced T cell-specific factor (TCF)/lymphoid enhancer-binding factor (LEF)-mediated transcription as measured using luciferase reporter assays. Gene silencing using small interfering RNA (siRNA) duplexes decreased ROR2 transcript and protein levels. In contrast, proliferation of SGHPL-4 trophoblasts, measured by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay was not affected. The siRNA-mediated downregulation of ROR2 in trophoblasts rescued CMV-induced reduction in trophoblast migration. These data suggest a mechanism where CMV alters the expression of the Wnt receptor ROR2 to alter Wnt5a-mediated signaling and inhibit trophoblast motility. Inhibition of this mechanism may be a target for therapeutic intervention for CMV-induced placental damage and consequent fetal damage in congenital CMV infections. IMPORTANCEMaternal primary cytomegalovirus (CMV) infection, reactivation, or reinfection with a different viral strain may cause fetal injury and adverse pregnancy outcomes. Increasing evidence indicates that fetal injury results not only from direct viral cytopathic damage to the CMV-infected fetus but also from indirect effects through placental infection and placental dysfunction. No effective therapy is currently proven to prevent or treat congenital CMV infection. Understanding the molecular underpinnings of CMV infection of the placenta is essential for therapeutic innovations and vaccine design. CMV alters canonical Wingless (Wnt) signaling, an essential cellular pathway involved in placental development. This study suggests a mechanism in which CMV alters the expression of noncanonical Wnt receptor ROR2 to alter motility of placental cells, which has important implications in the pathogenesis of CMV-induced placental dysfunction. Inhibition of this mechanism may be a target for therapeutic intervention for CMV-induced placental damage and consequent fetal damage in con...

Regulation of Wnt/β-catenin signaling by herpesviruses

“…By dysregulating the physiological condition of the Wnt/β-catenin pathway, HCMV inhibits or severely hampers the processes of cellular replication, movement/migration, and differentiation among others[41,42]. …”

“…Wnt5a interacts with the tyrosine-like orphan kinase 2 ROR2 and physiologically activates the Wnt/Planar Cell Polarity pathway and Wnt/Ca 2+ pathway[42]. During HCMV infection, infected cells become insensitive to normal Wnt5a ligand signaling but ROR2 expression is significantly increased.…”

Correlation of CXCR4/CXCR7 signaling pathway with pre-eclampsia

“…C-X-C chemokine receptor type 4 (CXCR4)/CXCR7 (9,10) is an important signaling pathway during pregnancy, which is highly expressed in the placenta. It is involved in embryogenesis and implantation of placenta; moreover, they can also form a dipolymer, aggregate β-inhibitory protein and activate its related signaling transduction pathways.…”

Cell-type specific activities of cytomegalovirus GPCR homologues

“…Taken together, this could explain the placenta damage and impaired development detected in infections. Moreover, it has also been reported that HCMV infection of trophoblasts can alter signalling pathways, such as Wnt/, expression of adhesion molecules, secretion of cytokines and cellular function, such as migration and invasion (Angelova et al, 2012;Hamilton et al, 2012;Schleiss et al, 2007;van Zuylen et al, 2016;Warner et al, 2012), causing further dysregulation of placenta functions. These changes are linked with higher risks of severe disease in the foetuses and poor pregnancy outcome during the first trimester (Enders et al, 2011;Pass et al, 2006).…”

“…HCMV infection is described to alter the expression of several chemokines Streblow et al, 1999) and chemokines can interfere with cell taxis (e.g., HCMV infection of cytotrophoblasts inhibits CXCL12 expression, which mediates migration of this cell type) (Warner et al, 2012). HCMV infection has also been associated with modulation of canonical and non-canonical Wnt signalling, thereby inhibiting trophoblast migration in response to Wnt ligands (Angelova et al, 2012;van Zuylen et al, 2015). It is possible that several alternative pathways, including those involving the vGPCR, may contribute to modulation of trophoblast migration and that the prevailing effects will depend upon the context of infection, for example differentiation state of the cell.…”