Actively replicating West Nile virus is resistant to cytoplasmic delivery of siRNA

• Main Authors: Diamond Michael S, Pierson Theodore C, Geiss Brian J
• Format: Article
• Language: English
• Published: BMC 2005-06-01
• Series: Virology Journal
• Online Access: http://www.virologyj.com/content/2/1/53

<p>Abstract</p> <p>Background</p> <p>West Nile virus is an emerging human pathogen for which specific antiviral therapy has not been developed. Recent studies have suggested that RNA interference (RNAi) has therapeutic potential as a sequence specific inhibitor of viral infection. Here, we examine the ability of exogenous small interfering RNAs (siRNAs) to block the replication of West Nile virus in human cells.</p> <p>Results</p> <p>WNV replication and infection was greatly reduced when siRNA were introduced by cytoplasmic-targeted transfection prior to but not after the establishment of viral replication. WNV appeared to evade rather than actively block the RNAi machinery, as sequence-specific reduction in protein expression of a heterologous transgene was still observed in WNV-infected cells. However, sequence-specific decreases in WNV RNA were observed in cells undergoing active viral replication when siRNA was transfected by an alternate method, electroporation.</p> <p>Conclusion</p> <p>Our results suggest that actively replicating WNV RNA may not be exposed to the cytoplasmic RNAi machinery. Thus, conventional lipid-based siRNA delivery systems may not be adequate for therapy against enveloped RNA viruses that replicate in specialized membrane compartments.</p>