title: Prophylactic and therapeutic effects of small interfering RNA targeting SARS-coronavirus.
abstract: OBJECTIVE
  To identify and characterize the siRNA duplexes that are effective for inhibition of SARS-CoV infection and replication in the non-human primate cells. This in vitro study will serve as the foundation for development of novel anti-SARS therapeutics.
  
  
  METHODS
  48 siRNA sequences were designed for targeting regions throughout entire SARS-CoV genome RNA including open-reading frames for several key proteins. Chemically synthesized siRNA duplexes were transfected into foetal rhesus kidney (FRhK-4) cells prior to or after SARS-CoV infection. The inhibitory effects of the siRNAs were evaluated for reductions of intracellular viral genome copy number and viral titres in the cell culture medium measured by Q-RT-PCR and CPE-based titration, respectively. Four siRNA duplexes were found to achieve potent inhibition of SARS-CoV infection and replication. A prolonged prophylactic effect of siRNA duplexes with up to 90% inhibition that lasted for at least 72 h was observed. Combination of active siRNA duplexes targeting different regions of the viral genome resulted in therapeutic activity of up to 80% inhibition.
  
  
  CONCLUSIONS
  Chemically synthesized siRNA duplexes targeting SARS-CoV genomic RNA are potent agents for inhibition of the viral infection and replication. The location effects of siRNAs were revealed at both genome sequence and open-reading frame levels. The rapid development of siRNA-based SARS-CoV inhibitors marked a novel approach for combating newly emergent infectious diseases.
authors.affiliation: Department of Microbiology, Institute of Molecular Biology, Department of Pathology, University of Hong Kong, Hong Kong, China.
authors.forename: Bo-jian
authors.initials: BJ
authors.lastname: Zheng
authors.forename: Yi
authors.initials: Y
authors.lastname: Guan
authors.forename: Qingquan
authors.initials: Q
authors.lastname: Tang
authors.forename: Cheng
authors.initials: C
authors.lastname: Du
authors.forename: Frank Y
authors.initials: FY
authors.lastname: Xie
authors.forename: Ming-Liang
authors.initials: ML
authors.lastname: He
authors.forename: Kwok-Wah
authors.initials: KW
authors.lastname: Chan
authors.forename: Kin-Ling
authors.initials: KL
authors.lastname: Wong
authors.forename: Eric
authors.initials: E
authors.lastname: Lader
authors.forename: Martin C
authors.initials: MC
authors.lastname: Woodle
authors.forename: Patrick Y
authors.initials: PY
authors.lastname: Lu
authors.forename: Baojian
authors.initials: B
authors.lastname: Li
authors.forename: Nanshan
authors.initials: N
authors.lastname: Zhong
mesh_terms: D000818:Animals; D000998:Antiviral Agents / Q000138:chemical synthesis; D002460:Cell Line; D003470:Culture Media; D003588:Cytopathogenic Effect, Viral / Q000502:physiology*; D015316:Genetic Therapy; D016679:Genome, Viral; D008253:Macaca mulatta; D034741:RNA, Small Interfering / Q000138:chemical synthesis / Q000235:genetics*; D012367:RNA, Viral / Q000037:antagonists & inhibitors* / Q000096:biosynthesis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D045473:Severe acute respiratory syndrome-related coronavirus / Q000235:genetics / Q000302:isolation & purification / Q000502:physiology*; D013997:Time Factors; D014162:Transfection; D014779:Virus Replication / Q000235:genetics
chemical_list: D000998:Antiviral Agents; D003470:Culture Media; D034741:RNA, Small Interfering; D012367:RNA, Viral