Anemoside B4 inhibits enterovirus 71 propagation in mice through upregulating 14-3-3 expression and type I interferon responses.

Enterovirus 71 (EV71) is the major pathogens of human hand, foot, and mouth disease (HFMD). EV71 efficiently escapes innate immunity responses of the host to cause infection. At present, no effective antiviral drugs for EV71 are available. Anemoside B4 (B4) is a natural saponin isolated from the roots of Pulsatilla chinensis (Bunge) Regel. P. chinensis extracts that shows a wide variety of biological activities. In this study, we investigated the antiviral activities of B4 against EV71 both in cell culture and in suckling mice. We showed that B4 (12.5-200 µM) dose dependently increased the viability of EV71-infected RD cells with an IC50 value of 24.95 ± 0.05 µM against EV71. The antiviral activity of B4 was associated with enhanced interferon (IFN)-ß response, since knockdown of IFN-ß abolished its antiviral activity. We also confirmed that the enhanced IFN response was mediated via activation of retinoic acid-inducible gene I (RIG-I) like receptors (RLRs) pathway, and it was executed by upregulation of 14-3-3 protein, which disrupted the interaction between yes-associated protein (YAP) and interferon regulatory factor 3 (IRF3). By using amino acids in cell culture (SILAC)-based proteomics profiling, we identified the Hippo pathway as the top-ranking functional cluster in B4-treated EV71-infected cells. In vivo experiments were conducted in suckling mice (2-day-old) infected with EV71 and subsequently B4 (200 mg · kg-1 · d-1, i.p.) was administered for 16 days. We showed that B4 administration effectively suppressed EV71 replication and improved muscle inflammation and limb activity. Meanwhile, B4 administration regulated the expressions of HFMD biomarkers IL-10 and IFN-γ, attenuating complications of EV71 infection. Collectively, our results suggest that B4 could enhance the antiviral effect of IFN-ß by orchestrating Hippo and RLRs pathway, and B4 would be a potential lead compound for developing an anti-EV71 drug.

Hederacolchiside C inhibits Enterovirus 71 propagation through activating innate immunity.

Enterovirus 71 (EV71), a newly emerging life-threatening pathogen induces hand-foot-mouth disease (HFMD), no effective vaccines or specific anti-viral treatments are currently available. In this study, the activity of hederacolchiside C (HSC) against EV71 was investigated, and the antiviral mechanism was explored. HSC displayed apparent antiviral activity in EV71-infected cells probably through activating the host innate immunity. Comparing with EV71-infected group at 24 hpi, the group pretreated with HSC dramatically increased the expression of MAVS, p-IRF3, IRF3 and IFN-ß, the innate immune effectors related to innate immunity. In addition, HSC displayed stronger antiviral activity in EV71-infected suckling mice in comparison with Ribavirin, a broad-spectrum antiviral drug. The results suggest that HSC could have potential as a pharmaceutical drug for HFMD.