West Nile Virus-Induced Cell Adhesion Molecules on Human Brain Microvascular Endothelial Cells Regulate Leukocyte Adhesion and Modulate Permeability of the In Vitro Blood-Brain Barrier Model

Abstract

Characterizing the mechanisms by which West Nile virus (WNV) causes blood-brain barrier (BBB) disruption, leukocyte infiltration into the brain and neuroinflammation is important to understand the pathogenesis of WNV encephalitis. Here, we examined the role of endothelial cell adhesion molecules (CAMs) in mediating the adhesion and transendothelial migration of leukocytes across human brain microvascular endothelial cells (HBMVE). Infection with WNV (NY99 strain) significantly induced ICAM-1, VCAM-1, and E-selectin in human endothelial cells and infected mice brain, although the levels of their ligands on leukocytes (VLA-4, LFA-1and MAC-1) did not alter. The permeability of the in vitro BBB model increased dramatically following the transmigration of monocytes and lymphocytes across the models infected with WNV, which was reversed in the presence of a cocktail of blocking antibodies against ICAM-1, VCAM-1, and E-selectin. Further, WNV infection of HBMVE significantly increased leukocyte adhesion to the HBMVE monolayer and transmigration across the infected BBB model. The blockade of these CAMs reduced the adhesion and transmigration of leukocytes across the infected BBB model. Further, comparison of infection with highly neuroinvasive NY99 and non-lethal (Eg101) strain of WNV demonstrated similar level of virus replication and fold-increase of CAMs in HBMVE cells suggesting that the non-neuropathogenic response of Eg101 is not because of its inability to infect HBMVE cells. Collectively, these results suggest that increased expression of specific CAMs is a pathological event associated with WNV infection and may contribute to leukocyte infiltration and BBB disruption in vivo. Our data further implicate that strategies to block CAMs to reduce BBB disruption may limit neuroinflammation and virus-CNS entry via ‘Trojan horse’ route, and improve WNV disease outcome.

Interferon-Regulatory Factor 5-Dependent Signaling Restricts Orthobunyavirus Dissemination to the Central Nervous System

“…However, these OROV-expressing cells were not sufficient to infect the CNS, as adoptive transfer of PBMCs or DCs from OROV-infected Irf5 Ϫ/Ϫ mice did not induce disease in naive WT or Irf5 Ϫ/Ϫ mice (data not shown). This result was not entirely unexpected, since infection of leukocytes alone does not disrupt the BBB in other viral models (37,38). Although further experiments are warranted, IRF-5 could regulate expression of molecules that sustain the BBB integrity.…”

Zika Virus Infects Human Sertoli Cells and Modulates the Integrity of the In Vitro Blood-Testis Barrier Model

“…To determine if ZIKV infection of SCs represents a route for the virus to enter the seminiferous tubules, we utilized an in vitro SCB model using transwell cell culture PET (polyethylene terephthalate) inserts and quantified the transmigration of ZIKV across the inserts. Since the SCB restricts the movement of ions, well-documented methods to assess the tightness of the tissue barrier, transendothelial electrical resistance (TEER) and fluorescein isothiocyanate (FITC)-labeled dextran (FITC-dextran) transmigration assays (18,19), were used. SCB permeability was assessed starting at day 4 after seeding and demonstrated a gradual increase of resistance from 25 to 110 to 130 ⍀/cm 2 , which was comparable to data from other SCB studies using similar inserts with a 0.3-cm 2 surface area (20).…”

“…However, virus titers in the LCS were approximately 1.5 to 2 logs lower than those in the UCS at all time points (P Ͻ 0.01), and as expected, no plaques were detected in the SCB models infected with UV-ZIKV. We further studied ZIKV transmigration across the BBB model, prepared as described in our previous studies (18,19). As shown in Fig.…”

Viral Infection of the Central Nervous System and Neuroinflammation Precede Blood-Brain Barrier Disruption during Japanese Encephalitis Virus Infection

“…There are two pathways by which inflammatory cytokines can regulate BBB permeability. First, inflammatory cytokines can upregulate the endothelial AMs, which in concert with chemotactic chemokines, facilitate rolling and adhesion of leukocytes on the endothelial wall, and migration into the affected site (61,62). In the brains of JEV-infected mice, the expression levels of ICAM-1, VCAM-1, and PECAM-1 are significantly elevated, indicating the potential for increased recruitment of mononuclear leukocytes from the periphery to the CNS.…”