Exploring gene-deleted adenoviral vectors for delivery of short hairpin RNAs and reduction of hepatitis B virus infection in mice.
BACKGROUND
RNA interference based therapeutic approaches hold promise for the treatment of patients chronically infected with hepatitis B virus (HBV). To conquer HBV infection, long-term suppression of target transcripts in all hepatocytes without toxic effects may be required. The present study explored gene-deleted adenoviral vectors (GD-AdV) lacking all viral coding sequences for delivery of the previously described short hairpin RNA (shRNA) HBVU6no.2, which was demonstrated to result in post-transcriptional knock-down of HBV transcripts.


METHODS
We established conditions for shRNA delivery expressed from GD-AdV in vitro and in vivo and observed up to 96% shRNA-mediated knockdown of luciferase expressed in mouse liver. To investigate in vivo efficacy of HBVU6no.2 expressed from a GD-AdV, we explored a transient and a transgenic mouse model for HBV infection.


RESULTS
We observed an up to 68% drop in serum HBV surface antigen (HBsAg) levels in the transient and the transgenic mouse model for HBV infection, respectively. Interestingly, we detected an up to 86% drop in HBsAg levels in both animal models after administration of a control GD-AdV encoding beta-galactosidase. In concordance with reduced serum HBsAg levels, we observed reduced HBV replication as demonstrated by Southern blot analysis of HBV genomes.


CONCLUSIONS
The present study demonstrates that GD-AdV can be used against HBV infection but the design of DNA sequences including shRNAs contained in the vector and virus-host interactions during superinfection needs to be carefully considered.
Rauschhuber
Christina
C
Max von Pettenkofer-Institute, Department of Virology, Ludwig-Maximilians-Universität München, Munich, Germany.
Xu
Hui
H
Salazar
Felix H
FH
Marion
Patricia L
PL
Ehrhardt
Anja
A
D000256:Adenoviridae / Q000235:genetics*; D000818:Animals; D015316:Genetic Therapy / Q000379:methods*; D005822:Genetic Vectors; D006509:Hepatitis B / Q000628:therapy*; D006514:Hepatitis B Surface Antigens / Q000235:genetics; D006515:Hepatitis B virus / Q000235:genetics*; D051379:Mice; D008822:Mice, Transgenic; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000627:therapeutic use*
D006514:Hepatitis B Surface Antigens; D034741:RNA, Small Interfering