Discovery of aurintricarboxylic acid as an inhibitor against influenza A,EV71 viral infection and study of immune evasion mediated byEV71 3C protease

• Main Author: 洪慧貞
• Other Authors: Tseng, Ching-Ping
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/55848460781730389708

博士 === 國立交通大學 === 生物科技學系 === 98 === RNA viruses have an extremely high mutation rate which causes serious diseases in human. There are two ways to solve this problem. One is to screen the novel compounds for against the RNA viruses, and the other one is to study the relationship between the virus and host cells to deal with emerging challenges. In this study, the RNA virus - influenza virus was used as a target virus. We established a neuraminidase (NA) chemiluminescent assay system for high throughtput enzyme inhibitor screening. After screening approximately 2000 structurally diverse compounds, we found that aurintricarboxylic acid (ATA) was a potent inhibitor for NA of both group-1 and group-2 influenza viruses. ATA was equally potent in inhibiting the NA activity derived from wild-type NA and its H274Y mutant renders NA resistance by oseltamivir. Molecular modeling experiments suggested that ATA binds to NA at substrate binding site. ATA has also been demonstrated to inhibit the replication of several RNA viruses. Furthermore, we identified the effects of ATA on the clinically important RNA virus - EV71 replication and to explore the underlying mechanism. In this study, ATA was found to be an inhibitor for the replication of EV71. Mode-of-action studies revealed that ATA was able to inhibit the RNA-dependent RNA polymerase (RdRp, 3D polymerase) activity of EV71, while neither the internal ribosomal entry site (IRES) mediated translation of viral polyprotein nor the viral 3C protease (3Cpro) activity was affected. Overall, findings in this study suggest that ATA is able to effectively inhibit EV71 replication through interfering with the viral 3D polymerase. IFN-??β is an antiviral cytokine and currently is used for treating viral infections. Meanwhile, many viruses are known to possess multiple strategies to escape the antiviral mechanism conferred by host’s IFN system. Because there is no proven therapy to treat EV71 infection, our goal is to understand the relationship between the viruses and host immune system. Through a bioinformatics approach, we found that several proteins involved in the IFN-response pathway are susceptible to cleavage by the EV-71 encoded 3C protease. Subsequent in vivo and in vitro cleavage assays will be performed to examine analytical results.