title: BPR2-D2 targeting viral ribonucleoprotein complex-associated function inhibits oseltamivir-resistant influenza viruses.
abstract: 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.
authors.affiliation: National Health Research Institutes, Miaoli, Taiwan. srshih@mail.cgu.edu.tw
authors.forename: Shin-Ru
authors.initials: SR
authors.lastname: Shih
authors.forename: Jim-Tong
authors.initials: JT
authors.lastname: Horng
authors.forename: Leo L M
authors.initials: LL
authors.lastname: Poon
authors.forename: Tzu-Chun
authors.initials: TC
authors.lastname: Chen
authors.forename: Jiann-Yih
authors.initials: JY
authors.lastname: Yeh
authors.forename: Hsing-Pang
authors.initials: HP
authors.lastname: Hsieh
authors.forename: Sung-Nain
authors.initials: SN
authors.lastname: Tseng
authors.forename: Chiayn
authors.initials: C
authors.lastname: Chiang
authors.forename: Wan-Ling
authors.initials: WL
authors.lastname: Li
authors.forename: Yu-Sheng
authors.initials: YS
authors.lastname: Chao
authors.forename: John T-A
authors.initials: JT
authors.lastname: Hsu
mesh_terms: 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
chemical_list: D000998:Antiviral Agents; D012261:Ribonucleoproteins; D014764:Viral Proteins; D053139:Oseltamivir