Hand, foot, and mouth disease (HFMD) is caused by enterovirus 71 (EV71) in infants and children under six years of age. HFMD is characterized by fever, mouth ulcers, and vesicular rashes on the palms and feet. EV71 also causes severe neurological manifestations, such as brainstem encephalitis and aseptic meningitis. Recently, frequent outbreaks of EV71 have occurred in the Asia-Pacific region, but currently, no effective antiviral drugs have been developed to treat the disease. In this study, we investigated the antiviral effect of salvianolic acid B (SalB) on EV71. SalB is a major component of the Salvia miltiorrhiza root and has been shown to be an effective treatment for subarachnoid hemorrhages and myocardial infarctions. HeLa cells were cultured in 12-well plates and treated with SalB (100 or 10 µg/ml) and 106 PFU/ml of EV71. SalB treatment (100 µg/ml) significantly decreased the cleavage of the eukaryotic eIF4G1 protein and reduced the expression of the EV71 capsid protein VP1. In addition, SalB treatment showed a dramatic decrease in viral infection, measured by immunofluorescence staining. The Akt signaling pathway, a key component of cell survival and proliferation, was significantly increased in EV71-infected HeLa cells treated with 100 µg/ml SalB. RT-PCR results showed that the mRNA for anti-apoptotic protein Bcl-2 and the cell cycle regulator Cyclin-D1 were significantly increased by SalB treatment. These results indicate that SalB activates Akt/PKB signaling and inhibits apoptosis in infected HeLa cells. Taken together, these results suggest that SalB could be used to develop a new therapeutic drug for EV71-induced HFMD.
Bibliographical noteFunding Information:
Byung-Kwan Lim and Sang-Jip Nam contributed as co-corresponding author for this study. This study was supported by grants from the National Research Foundation (NRF) of Korea provided by the Korean Government (NRF- 2016R1D1A1A02937046 to B.K. Lim) and by the Ministry of Science, ICT & Future Planning under grant NRF-2017R1D1A1B03028172 (to S.J. Nam).
Copyright © 2020 by The Korean Society for Microbiology and Biotechnology
- Enterovirus 71
- Hand-foot-mouth disease
- Salvianolic acid B