Differential Myocardial Gene Delivery by Recombinant Serotype-Specific Adeno-associated Viral Vectors

Abstract

Recombinant cross-packaging of adeno-associated virus (AAV) genome of one serotype into other AAV serotypes has the potential to optimize tissue-specific gene transduction and expression in the heart. To evaluate the role of AAV1 to 5 virion shells on AAV2 transgene transduction, we constructed hybrid vectors in which each serotype capsid coding domain was cloned into a common vector backbone containing AAV2 replication genes. Constructs were tested for expression in: (1) adult murine heart in vivo using direct injection of virus, (2) neonatal and adult murine ventricular cardiomyocytes in vitro, and (3) adult human ventricular cardiomyocytes in vitro, using green fluorescent protein (GFP) as the measurable transgene. Serotype 1 virus demonstrated the highest transduction efficiency in adult murine cardiomyocytes both in vitro and in vivo, while serotype 2 virus had the greater transduction efficiency in neonatal cardiomyocytes in vitro. Prolonged in vivo myocardial GFP expression was observed for up to 12 months using serotype 1 and 2 vectors only. In human cardiomyocytes, serotype 1 vector was superior in transduction efficiency, followed by types 2, 5, 4, and 3. These data establish a hierarchy for efficient serotype-specific vector transduction in myocardial tissue. AAV1 serotype packaging results in more efficient transduction of genes in the murine and human adult heart, compared to other AAV serotypes. Our results suggest that adult human cardiac gene therapy may be enhanced by the use of serotype 1-specific AAV vectors.

Augmentation of AAV-mediated cardiac gene transfer after systemic administration in adult rats

“…In contrast to the transient expression mediated by those vector systems, AAV vectors enable long-term gene expression in the heart of small and large animals. 5,16,24,37 Our study demonstrates that UTMD loaded with AAV-6 or -9 significantly increased cardiac reporter gene expression compared to systemic infusion of vectors without microbubbles in the presence of ultrasound. As the diagnostic ultrasound used in this study is not able to increase transduction itself, 34 the increased transduction efficiency in the microbubble group can be explained by high local vector concentration after destruction of AAV-loaded microbubbles in the cardiac capillaries and increased capillary permeability resulting from high velocity fluid microjets.…”

“…21 In comparison to AAV-2, AAV-6-pseudotyped vectors lead to higher myocardial transduction after intramyocardial injection and systemic administration. [22][23][24][25] Other AAV serotype vectors such as AAV-8 or -9 resulted in even higher cardiac transduction levels after intravenous injection in adult mice. [26][27][28] Specificity and efficiency of myocardial gene transfer with pseudotyped AAV vectors could be further increased using the 1.5 kb myosin light chain-2v promoter fused to a cytomegalovirus (CMV) enhancer.…”

Inhibition of HBV replication and gene expression in vitro and in vivo with a single AAV vector delivering two shRNA molecules

“…Recombinant AAV (rAAV) provides a non-pathogenic and latent infection by integration into the host genome. It also demonstrated high transduction efficiency in both dividing and non-dividing cells with persistent transgene expression (19,20). The AAV2 gene delivery system is undergoing clinical trials (from phase I to phase III) in several hospitals in the United States and no obvious toxicity or side-effects have been reported (18,21).…”

Angiogenic and antiangiogenic gene therapy

“…Blankinship et al 77 reported that rAAV6 effectively transduced skeletal muscle. Du et al 78 reported that delivery genes to myocardial tissue may be enhanced by AAV serotype 1-specific vectors.…”