Gene delivery approaches to heart failure treatment

Transduction and Genome Editing of the Heart with Adeno-Associated Viral Vectors Loaded onto Electrospun Polydioxanone Nonwoven Fabrics

In this study, we introduce electrospun polydioxanone (PDO) nonwoven fabrics as a platform for the delivery of adeno-associated virus (AAV) vectors for transduction and genome editing by adhering them to organ surfaces, including the heart. AAV vectors were loaded onto the PDO fabrics by soaking the fabrics in a solution containing AAV vectors. In vitro, the amount of AAV vectors loaded onto the fabrics could be adjusted by changing their concentration in the solution, and the number of cells expressing the green fluorescent protein (GFP) encoded by the AAV vectors increased in correlation with the increasing amount of loaded AAV vectors. In vivo, both transduction and genome editing resulted in the observation of GFP expression around AAV vector-loaded PDO fabrics attached to the surfaces of mouse hearts, indicating effective transduction and expression at the target site. These results demonstrate the great potential of electrospun PDO nonwoven fabrics carrying therapeutic AAV vectors for gene therapy.

Adenoviral gene transfer of sphingosine kinase 1 protects heart against ischemia/reperfusion-induced injury and attenuates its postischemic failure

Sphingosine kinase 1 (SPK1) has been identified as a central mediator of ischemia preconditioning and plays a protective role in ischemia/reperfusion (I/R)-induced cardiomyocyte death. In the present study, we investigated the protective effect of adenovirus-mediated SPK1 gene (Ad-SPK1) transfer on I/R-induced cardiac injury, and evaluated its therapeutic action on postinfarction heart failure. Cardiac SPK1 activity was increased about 5-fold by injection of Ad-SPK1, compared with injection of adenovirus carrying the green fluorescent protein gene (Ad-GFP). A more potent performance and a lower incidence of arrhythmia were observed in Ad-SPK1-injected hearts during the reperfusion period, compared with Ad-GFP-injected hearts. An enzymatic activity assay showed that creatine kinase release was also less in Ad-SPK1-injected hearts. To investigate the therapeutic action of the SPK1 gene on postischemic heart failure, the left anterior descending branch of the coronary artery in Wistar rats was ligated after direct intramyocardial injection of Ad-SPK1 or Ad-GFP as a control. Ad-SPK1 injection significantly preserved cardiac systolic and diastolic function, as evidenced by left ventricular (LV) systolic pressure, LV end-diastolic pressure, and peak velocity of contraction (dP/dt). The LV morphometric parameters of Ad-SPK1-treated animals were also preserved. In addition, SPK1 gene delivery significantly enhanced angiogenesis and reduced fibrosis. These results demonstrate that adenovirus-mediated SPK1 gene transfer could efficiently prevent I/R-induced myocardial injury and attenuate postischemic heart failure. Thus, SPK1 gene delivery would be a novel strategy for the treatment of coronary heart disease.

Biodegradable cationic polyester as an efficient carrier for gene delivery to neonatal cardiomyocytes

Viral-mediated gene delivery has been explored for the treatment and protection of cardiomyocytes, but so far there is only one report using cationic polymer for gene delivery to cardiomyocytes in spite of many advantages of polymer-mediated gene delivery. In this study, a cationic poly(beta-amino ester) (PDMA) with a degradable backbone and cleavable side chains was synthesized by Michael addition reaction. The toxicity of PDMA to neonatal mouse cardiomyocytes (NMCMs) was significantly lower than that of polyethyleneimine (PEI). PDMA formed stable polyplexes with pEGFP. The dissociation of the polyplexes could be triggered by PDMA degradation, and the dissociation time was tunable via the polymer/pEGFP ratio. In vitro transfection showed that PDMA was an effective and low toxic gene delivery carrier for NMCMs. The PDMA/pEGFP polyplexes transfected EGFP gene to NMCMs with about 28% efficiency and caused little death. In contrast, a significant portion of cardiomyocytes cultured with PEI/pEGFP died.

An engineered vascular endothelial growth factor-activating transcription factor induces therapeutic angiogenesis in ApoE knockout mice with hindlimb ischemia

OBJECTIVE

Angiogenesis is the growth and proliferation of blood vessels from existing vascular structures, and therapeutic angiogenesis seeks to promote blood vessel growth to improve tissue perfusion. Vascular endothelial growth factor (VEGF) is a prototypic angiogenic agent that exists in vivo in multiple isoforms, and studies with VEGF to date had used single isoform therapy with disappointing results. We tested plasmid and adenoviral vectors encoding a zinc-finger DNA-binding transcription factor (ZFP-32E) that was designed to increase the expression of all major VEGF isoforms in a preclinical model of peripheral arterial obstructive disease (PAOD) in hypercholesterolemic (ApoE knock-out) mice.

METHODS

Unilateral femoral artery ligation/excision was performed in 117 mice. At 7 days postoperatively, the ischemic tibialis anterior (TA) and gastrocnemius (GAS) muscles received either ZFP-32E treatment (125 microg of plasmid, 2.5 x 10(11) viral particle units [vpu] of adenovirus; some mice received a second plasmid injection 3 days later) or no-ZFP treatment (125 microg of beta-galactosidase [beta-gal], a plasmid-lacking insert, or an equal dose of adenoviral encoding beta-gal; some mice received a second plasmid injection 3 days later). Group 1 mice (n = 31) were euthanized 3 days later, and VEGF messenger RNA (mRNA) and protein levels were measured. Group 2 mice (n = 38) were euthanized 7 days later, and measures of capillary density, cell proliferation, and apoptosis were quantified. Group 3 mice (n = 48) were euthanized 28 days later, and changes in lower limb blood flow perfusion were measured.

RESULTS

In group 1, VEGF mRNA and protein levels were significantly higher in those with ZFP-32E treatment vs beta-gal. In group 2, capillary density and proliferating cells were significantly greater and apoptosis was significantly lower in those with ZFP-32E treatment vs beta-gal. Finally, in group 3, changes in the perfusion ratio (ischemic/nonischemic limb) at 21 days after injection were significantly greater in those with ZFP-32E treatment vs no-ZFP treatment.

CONCLUSION

The ability of this engineered zinc-finger VEGF-activating transcription factor to induce therapeutic angiogenesis in hypercholesterolemic mice suggests this approach warrants investigation as a novel approach to treat PAOD.

Impact of genomics on research in the rat

The need to translate genes to function has positioned the rat as an invaluable animal model for genomic research. The significant increase in genomic resources in recent years has had an immediate functional application in the rat. Many of the resources for translational research are already in place and are ready to be combined with the years of physiological knowledge accumulated in numerous rat models, which is the subject of this perspective. Based on the successes to date and the research projects under way to further enhance the infrastructure of the rat, we also project where research in the rat will be in the near future. The impact of the rat genome project has just started, but it is an exciting time with tremendous progress.