Potential entry receptors for human γ-herpesvirus into epithelial cells: A plausible therapeutic target for viral infections

Abstract

Herpesviruses are ubiquitous viruses, specifically the Epstein Barr virus (EBV). EBV and Kaposi's sarcoma-associated herpesvirus (KSHV) establish their latency for a long period in B-cells and their reactivation instigates dreadful diseases from cancer to neurological modalities. The envelope glycoprotein of these viruses makes an attachment with several host receptors. For instance; glycoprotein 350/220, gp42, gHgL and gB of EBV establish an attachment with CD21, HLA-DR, Ephs, and other receptor molecules to hijack the B- and epithelial cell machinery. Ephs are reported recently as potent receptors for EBV entry into epithelial cells. Eph receptors play a role in the maintenance and control of various cellular processes including morphology, adhesion, proliferation, survival and differentiation. Alterations in the structure and expression of Eph and ephrin (Eph ligands) molecules is entangled with various pathologies including tumours and neurological complications. Along with Eph, integrins, NRP, NMHC are also key players in viral infections as they are possibly involved in viral transmission, replication and persistence. Contrarily, KSHV gH is known to interact with EphA2 and -A4 molecules, whereas in the case of EBV only EphA2 receptors are being reported to date. The ELEFN region of KSHV gH was involved in the interaction with EphA2, however, the interacting region of EBV gH is elusive. Further, the gHgL of KSHV and EBV form a complex with the EphA2 ligand-binding domain (LBD). Primarily by using gL both KSHV and EBV gHgL bind to the peripheral regions of LBD. In addition to γ-herpesviruses, several other viruses like Nipah virus, Cedar virus, Hepatitis C virus and Rhesus macaque rhadinovirus (RRV) also access the host cells via Eph receptors. Therefore, we summarise the possible roles of Eph and ephrins in virus-mediated infection and these molecules could serve as potential therapeutic targets.