Verteporfin Inhibits Severe Fever with Thrombocytopenia Syndrome Virus Infection via Inducing the Degradation of the Viral Gn Protein

Background: Severe fever with thrombocytopenia syndrome virus (SFTSV) is a novel tick-borne bunyavirus, causing the hemorrhagic infectious disease of SFTS, with a case fatality rate up to 30% due to the absence of effective therapeutic interventions. Therefore, it is urgent to develop safe and effective therapeutic drugs to control this viral hemorrhagic fever. Methods: The activity of verteporfin (VP), screened from an FDA-approved drugs library, against SFTSV, was systematically evaluated in Huh7 cells in a wide range of concentrations. We performed time-of-addition experiments with VP, along with binding, endocytosis, and membrane fusion assays, to determine which part of the SFTSV life cycle VP has its effect on. The potential targets of VP were detected by a drug affinity responsive target stability (DARTS) assay. Results: VP exhibited a potent anti-SFTSV activity by blocking the initial viral binding to the target cells during viral entry via significantly inducing the degradation of the viral Gn protein. Conclusions: The VP-induced inhibition of SFTSV binding, the first step of viral invasion, suggested that VP might be an ideal and potent anti-SFTSV agent due to its prophylaxis and therapeutic effects on viral infection.