Herpes simplex virus type 1 (HSV-1) infection induces various clinical disorders, such as herpes simplex encephalitis (HSE), herpes simplex keratitis (HSK), and genital herpes. In clinical intervention, acyclovir (ACV) is the major therapeutic drug used to suppress HSV-1; however, ACV-resistant strains have gradually increased. In the present study, harringtonine (HT) significantly inhibited infection of HSV-1 as well as two ACV-resistant strains, including HSV-1 blue and HSV-1 153. Time-of-drug addition assay further revealed that HT mainly reduced the early stage of HSV-1 infection. We also demonstrated that HT mainly affected herpes virus entry mediator (HVEM) expression as shown by qPCR, Western Blot, and Immunofluorescence. Collectively, HT showed antiviral activity against HSV-1 and ACV-resistant strains by targeting HVEM and could be a promising therapeutic candidate for mitigating HSV-1-induced-pathogenesis.

We reported the discovery of 6-TG inhibition of HSV-1 infection and its inhibitory roles in HSK both in vitro and in vivo . 6-TG was shown to possess at least 10× more potent inhibitory activity against HSV-1 than ACV and GCV and, more importantly, inhibit ACV/GCV-resistant mutant viruses. Animal model studies showed that gel-formulated 6-TG topically applied to eyes locally infected with HSV-1 could significantly inhibit HSV-1 replication, alleviate virus-induced HSK pathogenesis, and improve eye conditions.

Herpes simplex virus-1 (HSV-1) infection of the eyes leads to herpes simplex virus keratitis (HSK), the main cause of infectious blindness in the world. As the current therapeutics for HSV-1 infection are rather limited and prolonged use of acyclovir (ACV)/ganciclovir (GCV) and in immunocompromised patients lead to the rise of drug resistant mutants, it underlines the urgent need for new antiviral agents with distinct mechanisms. Our study attempted to establish ras-related C3 botulinum toxin substrate 1 (Rac1) as a new therapeutic target for HSV-1 infection by using Rac1-specific inhibitors to evaluate the in vitro inhibition of virus growth. Our results showed that increased Rac1 activity facilitated HSV-1 replication and inhibition of Rac1 activity by NSC23766 and Ehop016 significantly reduced HSV-1 replication.Thus, we identified NSC23766 and Ehop016 as possessing potent anti-HSV-1 activities by suppressing the Rac1 activity, suggesting that Rac1 is a potential target for treating HSV-1-related diseases.