Dynasore, a small-molecule inhibitor of the
GTPase activity of
dynamin, inhibits the entry of several viruses, including herpes simplex virus (HSV), but its impact on other steps in the viral life cycle has not been delineated. The current study was designed to test the hypothesis that
dynamin is required for
viral protein trafficking and thus has pleiotropic inhibitory effects on HSV
infection.
Dynasore inhibited HSV-1 and HSV-2
infection of human epithelial and neuronal cells, including primary genital tract cells and human fetal neurons and astrocytes. Similar results were obtained when cells were transfected with a plasmid expressing dominant negative
dynamin. Kinetic studies demonstrated that
dynasore reduced the number of viral capsids reaching the nuclear pore if added at the time of viral entry and that, when added as late
as 8 h postentry,
dynasore blocked the transport of newly synthesized
viral proteins from the nucleus to the cytosol. Proximity
ligation assays demonstrated that treatment with
dynasore prevented the colocalization of VP5 and
dynamin. This resulted in a reduction in the number of viral capsids isolated from
sucrose gradients. Fewer capsids were observed by electron microscopy in
dynasore-treated cells than in control-treated cells. There were also reductions in infectious progeny released into culture supernatants and in cell-to-cell spread. Together, these findings suggest that targeting
dynamin-HSV interactions may provide a new strategy for HSV treatment and prevention.
IMPORTANCE: HSV
infections remain a global health problem associated with significant morbidity, particularly in neonates and immunocompromised hosts, highlighting the need for novel approaches to treatment and prevention. The current studies indicate that
dynamin plays a role in multiple steps in the viral life cycle and provides a new target for
antiviral therapy.
Dynasore, a small-molecule inhibitor of
dynamin, has pleiotropic effects on HSV-1 and HSV-2
infection and impedes viral entry, trafficking of
viral proteins, and capsid formation.