Viral polymerase inhibitors T-705 and T-1105 are potential inhibitors of Zika virus replication.
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ABSTRACT:
SUBMITTER: Cai L
PROVIDER: S-EPMC5563514 | biostudies-literature | 2017 Sep
REPOSITORIES: biostudies-literature
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Viral polymerase inhibitors T-705 and T-1105 are potential inhibitors of Zika virus replication.
Cai Lei L Sun Yajie Y Song Yabin Y Xu Likun L Bei Zhuchun Z Zhang Dongna D Dou Yuanyuan Y Wang Hongquan H
Archives of virology 20170608 9
Since 2015, 69 countries and territories have reported evidence of vector-borne Zika virus (ZIKV) transmission. Currently, there are no effective licensed vaccines or drugs available for the treatment or prevention of ZIKV infection. We tested a series of compounds for their ability to inhibit ZIKV replication in cell culture. The compounds in T-705 (favipiravir) and T-1105 were found to have antiviral activity, suggesting that these compounds are promising candidates for further development as ...[more]
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Project description:Zika virus (ZIKV) is one of the mosquito borne flavivirus with several outbreaks in past few years in tropical and subtropical regions. The non-structural proteins of flaviviruses are suitable active targets for inhibitory drugs due to their role in pathogenicity. In ZIKV, the non-structural protein 5 (NS5) RNA-Dependent RNA polymerase replicates its genome. Here we have performed virtual screening to identify suitable ligands that can potentially halt the ZIKV NS5 RNA dependent RNA polymerase (RdRp). During this process, we searched and screened a library of ligands against ZIKV NS5 RdRp. The selected ligands with significant binding energy and ligand-receptor interactions were further processed. Among the selected docked conformations, top five was further optimized at atomic level using molecular dynamic simulations followed by binding free energy calculations. The interactions of ligands with the target structure of ZIKV RdRp revealed that they form strong bonds within the active sites of the receptor molecule. The efficacy of these drugs against ZIKV can be further analyzed through in-vitro and in-vivo studies.
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Project description:BackgroundThe viral RNA-dependent RNA polymerase (RdRp) enzymes of the Flaviviridae family are essential for viral replication and are logically important targets for development of antiviral therapeutic agents. Zika virus (ZIKV) is a rapidly re-emerging human pathogen for which no vaccine or antiviral agent is currently available.MethodsTo facilitate development of ZIKV RdRp inhibitors, we have established an RdRp assay using purified recombinant ZIKV NS5 polymerase.ResultsWe have shown that both the hepatitis C virus (HCV) nucleoside inhibitor sofosbuvir triphosphate and a pyridoxine-derived non-nucleoside small-molecule inhibitor, DMB213, can act against ZIKV RdRp activity at IC 50 s of 7.3 and 5.2 μM, respectively, in RNA synthesis reactions catalysed by recombinant ZIKV NS5 polymerase. Cell-based assays confirmed the anti-ZIKV activity of sofosbuvir and DMB213 with 50% effective concentrations (EC 50 s) of 8.3 and 4.6 μM, respectively. Control studies showed that DMB213 did not inhibit recombinant HIV-1 reverse transcriptase and showed only very weak inhibition of HIV-1 integrase strand-transfer activity. The S604T substitution in motif B of the ZIKV RdRp, which corresponds to the S282T substitution in motif B of HCV RdRp, which confers resistance to nucleotide inhibitors, also conferred resistance to sofosbuvir triphosphate, but not to DMB213. Enzyme assays showed that DMB213 appears to be competitive with natural nucleoside triphosphate (NTP) substrates.ConclusionsRecombinant ZIKV RdRp assays can be useful tools for the screening of both nucleos(t)ide compounds and non-nucleotide metal ion-chelating agents that interfere with ZIKV replication.
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Project description:BackgroundZika virus (ZIKV), an arbovirus of global concern, has been associated with neurological complications including microcephaly in newborns and Guillain-Barré syndrome in adults. Like other flaviviruses, ZIKV depends on cholesterol to facilitate its replication; thus, cholesterol has been proposed as a therapeutic target to treat the infection using FDA-approved statins. Cholesterol is stored in intracellular lipid droplets (LD) in the form of cholesterol esters and can be regulated by autophagy. We hypothesize that the virus hijacks autophagy machinery as an early step to increase the formation of LD and viral replication, and that interference with this pathway will limit reproduction of virus.MethodsWe pretreated MDCK cells with atorvastatin or other inhibitors of autophagy prior to infection with ZIKV. We measured viral expression by qPCR for NS1 RNA and immunofluorescence for Zika E protein.ResultsAutophagy increases in virus-infected cells as early as 6 h post infection (hpi). In the presence of atorvastatin, LD are decreased, and cholesterol is reduced, targeting key steps in viral replication, resulting in suppression of replication of ZIKV is suppressed. Other both early- and late-acting autophagy inhibitors decrease both the number of LD and viral replication. Bafilomycin renders cholesterol is inaccessible to ZIKV. We also confirm previous reports of a bystander effect, in which neighboring uninfected cells have higher LD counts compared to infected cells.ConclusionsWe conclude that atorvastatin and inhibitors of autophagy lead to lower availability of LD, decreasing viral replication. We conclude that bafilomycin A1 inhibits viral expression by blocking cholesterol esterification to form LD. Video Abstract.
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