Activation of EGFR on monocytes is required for human cytomegalovirus entry and mediates cellular motility

Abstract

Human cytomegalovirus (HCMV) rapidly induces a mobile and functionally unique proinflammatory monocyte following infection that is proposed to mediate viral spread. The cellular pathways used by HCMV to initiate these biological changes remain unknown. Here, we document the expression of the epidermal growth factor receptor (EGFR) on the surface of human peripheral blood monocytes but not on other blood leukocyte populations. Inhibition of EGFR signaling abrogated viral entry into monocytes, indicating that EGFR can serve as a cellular tropism receptor. Moreover, HCMV-activated EGFR was required for the induction of monocyte motility and transendothelial migration, two biological events required for monocyte extravasation into peripheral tissue, and thus viral spread. Transcriptome analysis revealed that HCMV-mediated EGFR signaling up-regulated neural Wiskott-Aldrich syndrome protein (N-WASP), an actin nucleator whose expression and function are normally limited in leukocytes. Knockdown of N-WASP expression blocked HCMV-induced but not phorbol 12-myristate 13-acetate (PMA)-induced monocyte motility, suggesting that a switch to and/or the distinct use of a new actin nucleator controlling motility occurs during HCMV infection of monocytes. Together, these data provide evidence that EGFR plays an essential role in the immunopathobiology of HCMV by mediating viral entry into monocytes and stimulating the aberrant biological activity that promotes hematogenous dissemination.T he wide range of pathological complications associated with human cytomegalovirus (HCMV) infection is a direct consequence of viral spread to peripheral organ sites and the broad cellular tropism of the virus (1). Monocytes are primary in vivo targets for HCMV and are believed to be responsible for hematogenous dissemination of HCMV to multiple organ systems (2). We previously showed that HCMV infection of monocytes polarized the infected cell toward a distinct proinflammatory phenotype that possessed the distinct biological changes necessary to promote viral spread (3-5). Specifically, HCMV infection induced polarization of infected monocytes toward an M1 proinflammatory cell type that simultaneously exhibited characteristics associated with an M2 antiinflammatory macrophage (6). The infected monocytes also displayed a high level of chemokinesis when compared with monocytes activated by LPS or phorbol 12-myristate 13-acetate (PMA) (4, 5). Moreover, an accelerated rate of differentiation from short-lived monocytes (nonpermissive for HCMV replication) into long-lived macrophages (permissive for HCMV replication) was observed following infection with HCMV (4). Based on our studies, we suggest that during primary infection, newly infected peripheral monocytes acquire a motile phenotype that promotes exit of the infected cell from the circulating blood into multiple organ tissue despite the absence of a chemotactic gradient. Once in the surrounding tissue, differentiation into HCMV replication-competent macrophages occurs, resulting in viral spread...

Human cytomegalovirus infection of human adipose-derived stromal/stem cells restricts differentiation along the adipogenic lineage

“…1). [38][39][40] CD90 has also been linked to HCMV entry, possibly through interaction with HCMV envelope associated glycoproteins. 41 Interestingly, HCMV infection strongly up-regulates expression of PDGFR and CD61, slightly increases CD90 but has no effect on CD29 or EGFR.…”

EGFR and HER2 receptor kinase signaling mediate epithelial cell invasion by Candida albicans during oropharyngeal infection

“…For example, EGFR mediates the uptake of cytomegalovirus by monocytes and influenza A virus by epithelial cells (18,19). Also, HER2 signaling stimulates endothelial cell invasion by Neisseria meningitidis and neuronal demyelination in response to Mycobacterium leprae (20,21).…”

Viral binding-induced signaling drives a unique and extended intracellular trafficking pattern during infection of primary monocytes

“…Understanding how HCMV overcomes these biological barriers following infection may provide clues to the underlying causes of HCMV pathogenesis and persistence. Our laboratory has provided molecular evidence for how HCMV evolved to deal with these biological barriers (16)(17)(18)(19)(20)(21)(22).We have shown that the biological changes in HCMV-infected monocytes are triggered by the binding of gB to EGFR (19) and binding of the gH/gL/UL128-131 complex to β1 and β3 integrins (7, 18). These receptor-ligand interactions trigger the EGFR and integrin signaling cascades, promoting enhanced motility and viral entry into monocytes (16,19).…”

“…Understanding how HCMV overcomes these biological barriers following infection may provide clues to the underlying causes of HCMV pathogenesis and persistence. Our laboratory has provided molecular evidence for how HCMV evolved to deal with these biological barriers (16)(17)(18)(19)(20)(21)(22).…”

“…These receptor-ligand interactions trigger the EGFR and integrin signaling cascades, promoting enhanced motility and viral entry into monocytes (16,19). The gB/EGFR interaction also allows infected cells to escape the early cellular apoptotic mechanism through the prolonged expression of myeloid cell leukemia-1 (Mcl-1) (20).…”