Topoisomerase inhibition accelerates gene expression after adeno-associated virus-mediated gene transfer to the mammalian heart.

Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia 22903, USA.
Molecular Therapy (Impact Factor: 6.43). 05/2007; 15(4):764-71. DOI: 10.1038/
Source: PubMed

ABSTRACT Utility of adeno-associated virus 2 (AAV2) vectors for cardiac gene therapy is limited by the prolonged lag phase before maximal gene expression. Topoisomerase inhibition can induce AAV2-mediated gene expression in vivo, but with variable success in different tissues. In this study, we demonstrate that topoisomerase inhibition can accelerate AAV2-mediated gene expression in the mouse heart. We used an AAV2 vector expressing firefly luciferase and monitored expression kinetics using non-invasive bioluminescence imaging. In the group receiving vector alone, cardiac luciferase activity was evident from week 2 onward and increased progressively to reach a steady plateau by 9 weeks postinjection. In the group receiving vector and camptothecine (CPT), luciferase expression was evident from days 2 to 4 onward and increased rapidly to reach a steady plateau by 3-4 weeks postinjection, nearly three times faster than in the absence of CPT (P<0.05). Southern blot analysis of AAV2 genomes in cardiac tissue showed rapid conversion of the AAV2 genome from its single-stranded to double-stranded form in CPT-treated mice. Non-invasive determinations of luciferase expression correlated well with in vitro luciferase assays. Direct injection of the AAV2 vector and long-term luciferase gene expression had no detectable effects on normal cardiac function as assessed by magnetic resonance imaging.


Available from: Stuart Berr, Aug 12, 2014
  • [Show abstract] [Hide abstract]
    ABSTRACT: The field of gene therapy has been increasingly studied in the last four decades, and its clinical application has become a reality in the last 15 years. Traditional Chinese medicine (TCM), an important component of complementary and alternative medicine, has evolved over thousands of years with its own unique system of theories, diagnostics and therapies. TCM is well-known for its various roles in preventing and treating infectious and chronic diseases, and its usage in other modern clinical practice. However, whether TCM can be applied alongside gene therapy is a topic that has not been systematically examined. Here we provide an overview of TCM theories in relation to gene therapy. We believe that TCM theories are congruent with some principles of gene therapy. TCM-derived drugs may also act as gene therapy vehicles, therapeutic genes, synergistic therapeutic treatments, and as co-administrated drugs to reduce side effects. We also discuss in this review some possible approaches to combine TCM and gene therapy.
    03/2014; 12(2):67-75. DOI:10.1016/S2095-4964(14)60019-4
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: AAV9 is a powerful gene delivery vehicle capable of providing long-term gene expression in a variety of cell types, particularly cardiomyocytes. The use of AAV-delivery for RNA interference is an intense area of research, but a comprehensive analysis of knockdown in cardiac and liver tissues after systemic delivery of AAV9 has yet to be reported. We sought to address this question by using AAV9 to deliver a short-hairpin RNA targeting the enhanced green fluorescent protein (GFP) in transgenic mice that constitutively overexpress GFP in all tissues. The expression cassette was initially tested in vitro and we demonstrated a 61% reduction in mRNA and a 90% reduction in GFP protein in dual-transfected 293 cells. Next, the expression cassette was packaged as single-stranded genomes in AAV9 capsids to test cardiac GFP knockdown with several doses ranging from 1.8×10(10) to 1.8×10(11) viral genomes per mouse and a dose-dependent response was obtained. We then analyzed GFP expression in both heart and liver after delivery of 4.4×10(11) viral genomes per mouse. We found that while cardiac knockdown was highly efficient, with a 77% reduction in GFP mRNA and a 71% reduction in protein versus control-treated mice, there was no change in liver expression. This was despite a 4.5-fold greater number of viral genomes in the liver than in the heart. This study demonstrates that single-stranded AAV9 vectors expressing shRNA can be used to achieve highly efficient cardiac-selective knockdown of GFP expression that is sustained for at least 7 weeks after the systemic injection of 8 day old mice, with no change in liver expression and no evidence of liver damage despite high viral genome presence in the liver.
    PLoS ONE 09/2013; 8(9):e75894. DOI:10.1371/journal.pone.0075894 · 3.53 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Proteasome inhibitors (e.g. bortezomib, MG132) are known to enhance adeno-associated virus (AAV) transduction; however, whether this results from pleotropic proteasome inhibition or off-target serine and/or cysteine protease inhibition remains unresolved. Here, we examined rAAV effects of a new proteasome inhibitor, carfilzomib, which specifically inhibits chymotrypsin-like proteasome activity and no other proteases. We determined proteasome inhibitors act on rAAV through proteasome inhibition and not serine or cysteine protease inhibition, likely through positive changes late in transduction.
    Journal of Virology 09/2013; DOI:10.1128/JVI.01826-13 · 4.65 Impact Factor

Similar Publications