JAC Advance Access published online on November 5, 2009
Journal of Antimicrobial Chemotherapy, doi:10.1093/jac/dkp393
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Original research |
BPR2-D2 targeting viral ribonucleoprotein complex-associated function inhibits oseltamivir-resistant influenza viruses
1 Division of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Miaoli, Taiwan 2 Research Center for Emerging Viral Infections, Tao-Yuan, Taiwan 3 Department of Medical Biotechnology & Laboratory Science, Chang Gung University, Tao-Yuan, Taiwan 4 Clinical Virology Laboratory, Chang-Gung Memorial Hospital, Tao-Yuan, Taiwan 5 Department of Biochemistry and Molecular Biology, Chang Gung University, Tao-Yuan, Taiwan 6 Department of Microbiology, The University of Hong Kong, Hong Kong SAR, China 7 Department of Biological Science and Technology, National Chiao Tung University, Hsinchu, Taiwan
Received 13 June 2009; returned 20 July 2009; revised 7 October 2009; accepted 8 October 2009
* Corresponding author. Department of Medical Biotechnology and Laboratory Science, Chang Gung University, 259 Wen-Hua 1st Rd, Kwei-Shan, Taoyuan, 333, Taiwan. Tel: +886-3-2118800, ext. 5497; Fax: +886-3-2118174; E-mail: srshih{at}mail.cgu.edu.tw
Objectives: The emergence of oseltamivir-resistant viruses raised the global threat with regard to influenza virus infection. To develop alternative antiviral agents against influenza virus infection is significant and urgent.
Methods: A neutralization test was applied as a screening assay and a plaque reduction assay was used for confirmation. Expression plasmids for viral ribonucleoproteins (RNPs) and a plasmid that allowed expression of a pseudoviral reporter RNA were transfected into cells to investigate the effects of a novel antiviral compound on viral RNA synthesis.
Results: BPR2-D2 was identified as a novel inhibitor against influenza virus from a hit obtained from high throughput screening of 20 000 or more compounds. BPR2-D2 exhibited an excellent antiviral efficacy for the oseltamivir-resistant virus (EC50 ranging from 0.021 to 0.040 µM). No resistant virus was produced throughout 20 passages in the presence of BPR2-D2, whereas oseltamivir-resistant virus was generated at passage 8 using the same experimental system. A molecular target other than neuraminidase (NA) was found because BPR2-D2 inhibited the synthesis of viral RNA that was driven by influenza viral RNP in a transfection assay. BPR2-D2 also exhibited a broad antiviral spectrum against various strains of influenza A and influenza B viruses.
Conclusions: BPR2-D2 was identified as a novel inhibitor of influenza virus. It may target viral RNPs that are responsible for viral RNA synthesis. Targeting different molecules compared with NA allows BPR2-D2 to inhibit oseltamivir-resistant viruses.
Key Words: antiviral agent , viral RNA , influenza A virus