Cell-specific decoy oligodeoxynucleotide delivery to the failing heart

Coordinator:		Prof. Dr. med. Oliver Müller / Prof. Dr. Raffi Bekeredjian
Institution:		Div. of Internal Medicine III, Heidelberg University Hospital
Homepage:		www.klinikum.uni-heidelberg.de/Labor-Mueller

Objective of subproject 3 was the establishment of an efficient and cell-specific transfer system, primarily to introduce systemically administered decoy ODN into the heart muscle in vivo. To this end modified AAV capsids based on the cardiotropic serotype 9, in which one quarter of the capsid proteins was altered so that the nucleic acids can be bound to the surface of the virus, were developed as a shuttle. These chimeric virus particles are in principle suitable for the transduction of cardiomyocytes in vivo, as the expression of a gene encoding the red fluorescent protein reporter plasmid showed. However, only about 10% of the plasmid DNA bound to the virus particles penetrated into eukaryotic cells in vitro. In an in vivo approach (in the mouse) it could be further shown that at a mixing ratio of 1:3 of specially modified to wild type capsid subunits merely decreases the transduction efficacy of the AAV9 vectors to about 50%, while cardiac specificity was maintained. Although this approach is basically suitable as a strategy for an in vivo gene transfer, the cell-specific transfer of decoy ODNs in vivo nevertheless proved inefficient. Therefore, in the course of the project sonoporation, in which microbubbles, well established reagents in medical diagnostics, are loaded with DNA constructs and then destroyed at the target site by ultrasound to deliver their cargo to the surrounding cells, was developed further.


Sonoporation (start animation). Gas-filled microspheres laden with the DNA constructs are injected intravenously. They are distributed in the capillaries and can be destroyed in the target organ with locally applied ultrasound, so that the transported substance is released into the surrounding tissue.


Additional relevant Internet links:
Avontec GmbH
Institut für Physiologie und Pathophysiologie, Universität Heidelberg
Abteilung Innere Medizin III, Universität Heidelberg