BPR2-D2 targeting viral ribonucleoprotein complex-associated function inhibits oseltamivir-resistant influenza viruses.
OBJECTIVE
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 (EC(50) ranging from 0.021 to 0.040 microM). 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.
Shih
Shin-Ru
SR
National Health Research Institutes, Miaoli, Taiwan. srshih@mail.cgu.edu.tw
Horng
Jim-Tong
JT
Poon
Leo L M
LL
Chen
Tzu-Chun
TC
Yeh
Jiann-Yih
JY
Hsieh
Hsing-Pang
HP
Tseng
Sung-Nain
SN
Chiang
Chiayn
C
Li
Wan-Ling
WL
Chao
Yu-Sheng
YS
Hsu
John T-A
JT
D000998:Antiviral Agents / Q000494:pharmacology*; D002460:Cell Line; D004353:Drug Evaluation, Preclinical; D024882:Drug Resistance, Viral; D006801:Humans; D020128:Inhibitory Concentration 50; D015394:Molecular Structure; D009500:Neutralization Tests; D009975:Orthomyxoviridae / Q000187:drug effects* / Q000235:genetics; D053139:Oseltamivir / Q000494:pharmacology*; D012261:Ribonucleoproteins / Q000037:antagonists & inhibitors* / Q000235:genetics; D014162:Transfection; D010948:Viral Plaque Assay; D014764:Viral Proteins / Q000037:antagonists & inhibitors* / Q000235:genetics
D000998:Antiviral Agents; D012261:Ribonucleoproteins; D014764:Viral Proteins; D053139:Oseltamivir