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Anti- Japanese-Encephalitis-Viral Effects of Kaempferol and Daidzin and Their RNA-Binding Characteristics

BACKGROUND: New therapeutic tools and molecular targets are needed for treatment of Japanese encephalitis virus (JEV) infections. JEV requires an α-1 translational frameshift to synthesize the NS1' protein required for viral neuroinvasiveness. Several flavonoids have been shown to possess antiv...

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Autores principales: Zhang, Ting, Wu, Zhiqiang, Du, Jiang, Hu, Yongfeng, Liu, Liguo, Yang, Fan, Jin, Qi
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2012
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3262791/
https://www.ncbi.nlm.nih.gov/pubmed/22276167
http://dx.doi.org/10.1371/journal.pone.0030259
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author Zhang, Ting
Wu, Zhiqiang
Du, Jiang
Hu, Yongfeng
Liu, Liguo
Yang, Fan
Jin, Qi
author_facet Zhang, Ting
Wu, Zhiqiang
Du, Jiang
Hu, Yongfeng
Liu, Liguo
Yang, Fan
Jin, Qi
author_sort Zhang, Ting
collection PubMed
description BACKGROUND: New therapeutic tools and molecular targets are needed for treatment of Japanese encephalitis virus (JEV) infections. JEV requires an α-1 translational frameshift to synthesize the NS1' protein required for viral neuroinvasiveness. Several flavonoids have been shown to possess antiviral activity in vitro against a wide spectrum of viruses. To date, the antiviral activities of flavonol kaempferol (Kae) and isoflavonoid daidzin (Dai) against JEV have not been described. METHODOLOGY/PRINCIPAL FINDINGS: The 50% cytotoxic concentration (CC(50)) and 50% effective concentration (EC(50)) against JEV were investigated in BHK21 cells by MTS reduction. Activity against viral genomic RNA and proteins was measured by real-time RT-PCR and western blotting. The frameshift site RNA-binding characterization was also determined by electrospray ionization mass spectrometry, isothermal titration calorimetry and autodocking analysis. EC(50) values of Kae and Dai were 12.6 and 25.9 µM against JEV in cells pretreated before infection, whereas in cells infected before treatment, EC(50) was 21.5 and 40.4 µM, respectively. Kae exhibited more potent activity against JEV and RNA binding in cells following internalization through direct inhibition of viral replication and protein expression, indicating that its antiviral activity was principally due to direct virucidal effects. The JEV frameshift site RNA (fsRNA) was selected as a target for assaying Kae and Dai. ITC of fsRNA revealed an apparent K(b) value for Kae that was nine fold stronger than that for Dai. This binding was confirmed and localized to the RNA using ESI-MS and autodock analysis. Kae could form non-covalent complexes with fsRNA more easily than Dai could. CONCLUSIONS/SIGNIFICANCE: Kae demonstrates more potent antiviral activity against JEV than does Dai. The mode of action of Kae as an anti-JEV agent seems to be related to its ability to inactivate virus by binding with JEV fsRNA.
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spelling pubmed-32627912012-01-24 Anti- Japanese-Encephalitis-Viral Effects of Kaempferol and Daidzin and Their RNA-Binding Characteristics Zhang, Ting Wu, Zhiqiang Du, Jiang Hu, Yongfeng Liu, Liguo Yang, Fan Jin, Qi PLoS One Research Article BACKGROUND: New therapeutic tools and molecular targets are needed for treatment of Japanese encephalitis virus (JEV) infections. JEV requires an α-1 translational frameshift to synthesize the NS1' protein required for viral neuroinvasiveness. Several flavonoids have been shown to possess antiviral activity in vitro against a wide spectrum of viruses. To date, the antiviral activities of flavonol kaempferol (Kae) and isoflavonoid daidzin (Dai) against JEV have not been described. METHODOLOGY/PRINCIPAL FINDINGS: The 50% cytotoxic concentration (CC(50)) and 50% effective concentration (EC(50)) against JEV were investigated in BHK21 cells by MTS reduction. Activity against viral genomic RNA and proteins was measured by real-time RT-PCR and western blotting. The frameshift site RNA-binding characterization was also determined by electrospray ionization mass spectrometry, isothermal titration calorimetry and autodocking analysis. EC(50) values of Kae and Dai were 12.6 and 25.9 µM against JEV in cells pretreated before infection, whereas in cells infected before treatment, EC(50) was 21.5 and 40.4 µM, respectively. Kae exhibited more potent activity against JEV and RNA binding in cells following internalization through direct inhibition of viral replication and protein expression, indicating that its antiviral activity was principally due to direct virucidal effects. The JEV frameshift site RNA (fsRNA) was selected as a target for assaying Kae and Dai. ITC of fsRNA revealed an apparent K(b) value for Kae that was nine fold stronger than that for Dai. This binding was confirmed and localized to the RNA using ESI-MS and autodock analysis. Kae could form non-covalent complexes with fsRNA more easily than Dai could. CONCLUSIONS/SIGNIFICANCE: Kae demonstrates more potent antiviral activity against JEV than does Dai. The mode of action of Kae as an anti-JEV agent seems to be related to its ability to inactivate virus by binding with JEV fsRNA. Public Library of Science 2012-01-20 /pmc/articles/PMC3262791/ /pubmed/22276167 http://dx.doi.org/10.1371/journal.pone.0030259 Text en Zhang et al. http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited.
spellingShingle Research Article
Zhang, Ting
Wu, Zhiqiang
Du, Jiang
Hu, Yongfeng
Liu, Liguo
Yang, Fan
Jin, Qi
Anti- Japanese-Encephalitis-Viral Effects of Kaempferol and Daidzin and Their RNA-Binding Characteristics
title Anti- Japanese-Encephalitis-Viral Effects of Kaempferol and Daidzin and Their RNA-Binding Characteristics
title_full Anti- Japanese-Encephalitis-Viral Effects of Kaempferol and Daidzin and Their RNA-Binding Characteristics
title_fullStr Anti- Japanese-Encephalitis-Viral Effects of Kaempferol and Daidzin and Their RNA-Binding Characteristics
title_full_unstemmed Anti- Japanese-Encephalitis-Viral Effects of Kaempferol and Daidzin and Their RNA-Binding Characteristics
title_short Anti- Japanese-Encephalitis-Viral Effects of Kaempferol and Daidzin and Their RNA-Binding Characteristics
title_sort anti- japanese-encephalitis-viral effects of kaempferol and daidzin and their rna-binding characteristics
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3262791/
https://www.ncbi.nlm.nih.gov/pubmed/22276167
http://dx.doi.org/10.1371/journal.pone.0030259
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