Antiviral potential of a novel compound CW-33 against enterovirus A71 via inhibition of viral 2A protease

Enterovirus A71 (EV-A71) in the Picornaviridae family causes hand-foot-and-mouth disease, aseptic meningitis, severe central nervous system disease, even death. EV-A71 2A protease cleaves Type I interferon (IFN)-α/β receptor 1 (IFNAR1) to block IFN-induced Jak/STAT signaling. This study investigated anti-EV-A7l activity and synergistic mechanism(s) of a novel furoquinoline alkaloid compound CW-33 alone and in combination with IFN-β. Anti-EV-A71 activities of CW-33 alone and in combination with IFN-(3 were evaluated by inhibitory assays of virus-induced apoptosis, plaque formation, and virus yield. CW-33 showed antiviral activities with an IC50 of near 200 (J.M in EV-A71 plaque reduction and virus yield inhibition assays. While, anti-EV-A71 activities of CW-33 combined with 100 U/mL IFN-(3 exhibited a synergistic potency with an IC50 of approximate 1 (J.M in plaque reduction and virus yield inhibition assays. Molecular docking revealed CW-33 binding to EV-A71 2A protease active sites, correlating with an inhibitory effect of CW33 on in vitro enzymatic activity of recombinant 2A protease (IC50 = 53.1 (J-M). Western blotting demonstrated CW-33 specifically inhibiting 2A protease-mediated cleavage of IFNAR1. CW-33 also recovered Type I IFN-induced Tyk2 and STAT1 phosphorylation as well as 2^/,5^/-OAS upregulation in EV-A71 infected cells. The results demonstrated CW-33 inhibiting viral 2A protease activity to reduce Type IIFN antagonism of EV-A71. Therefore, CW-33 combined with a low-dose of Type I IFN could be applied in developing alternative approaches to treat EV-A71 infection.