Efficacy of Host-Kinase Inhibitors as Antiviral Agents Against Venezuelan Equine Encephalitis Virus

Abstract

Venezuelan equine encephalitis virus (VEEV) is a New World alphavirus that is naturally transmitted through mosquito vectors resulting in human infections. This virus is classified as a category B pathogen and a select agent as it is highly infectious and retains infectivity when transmitted as an aerosol. There is currently no therapeutic or vaccine candidate that is available to the civilian population for the treatment of VEEV exposures. With the ability of viruses to develop resistance to antiviral strategies that target viral components, it will be of strategic value to target specific host proteins to inhibit the viral life-cycle. Such host-based therapeutic candidates are also likely to find broad spectrum applicability in the treatment of infections by of other viral pathogens in addition to VEEV that employ the same host-based candidates. We show that inhibition of host kinases, AP2-associated protein kinase 1 (AAK1) and cyclin G-associated kinase (GAK), associated with clathrin-mediated endocytosis and intracellular trafficking results in a decrease of VEEV load in infected cells. siRNA knockdown of AAK and GAK yielded a decrease in viral titers along with alteration of viral protein levels. The small molecules azaindole and erlotinib (FDA approved) were found to have strong antiviral properties. Both drugs affected the ability of the virion to traffic effectively through the cell, preventing the movement from the plasma membrane and potentially, the ER network. Time of addition experiments showed that the drugs exhibit therapeutic potential, as both worked against established infections. These results show the effectiveness of AAK and GAK inhibitors in inhibiting VEEV infection. Ongoing research is exploring the mechanisms involved in this inhibitory process.