Consortium heart failure therapy - From gene regulation to disease: Decoy oligodeoxynucleotide prevention of heart failure

Coordinator:    Prof. Dr. Markus Hecker
Institution: Institute of Physiology and Pathophysiology, Heidelberg University
The aim of this NGFN-Transfer Innovation Alliance was the preclinical validation of decoy oligodeoxynucleotides (ODNs) as a new class of drugs for the treatment of heart failure. Decoy ODNs interfere with the aberrant expression of disease-associated genes by specifically inhibiting the transcription factor(s) necessary for the expression of these genes. As targets the transcription factor families activator protein-1 (AP-1), nuclear factor interleukin-6 (NF-IL6) and nuclear factor of activated T cells (NFAT) were investigated. It was intended to develop specific decoy ODNs with an optimized design and to establish the respective target gene profiles in the heart. The proof of efficacy for the decoy ODNs was to be furnished in vitro and in animal models either specifically developed within the project or provided by the NGFN-Plus Consortium Genetics of Heart Failure. In addition, a method for the systemic, yet cell-specific in vivo application of these nucleic acid-based therapeutics based on artificial viral capsids or microbubbles was to be developed. Sub-project 2 in particular was conducted in close collaboration with the NGFN-Plus Consortium Genetics of Heart Failure in Heidelberg.

In subproject 1 and 2 highly effective decoy ODNs against the transcription factors NFATc1, 2, -3 and -4 were developed, and the in vitro proof of efficacy was established in isolated cardiomyocytes and cardiac fibroblasts of neonatal rats. However, since in contrast to practically all other cell types tested so far, transfection reagents, which are hardly or not at all applicable in humans, had to be used for the transfer of decoy ODNs into these cells, the microbubble technique, which was primarily established in vivo, was adapted so that it could also be used on cultured cells. An in vivo mouse model, in which implanted minipumps continuously release angiotensin II leading to the development of hypertrophy and fibrosis of the left heart, was established for future tests on the living organ for the proof of efficacy for the various decoy ODNs.

Subproject 3 had the task of developing a system for the systemic in vivo application of decoy ODNs which at the same time allows for an efficient and specific transfection of the cells in the heart muscle. For this purpose, modified shells (capsids) of adeno-associated viruses (AAV), which are nonpathogenic, were developed. These modified virus particles are in principle suitable for the in vivo transduction of cardiomyocytes, as was demonstrated by the expression of reporter plasmids. 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 shown that, in principle, the transduction efficiency of AAV vectors can be increased without losing organ specificity by using capsids consisting of a mixture of wild-type and modified capsids to which the DNA constructs can bind.

As part of the NGFN-Transfer Innovation Alliance innovative DNA-based drugs for the treatment of heart failure, one of the most common fatal diseases in industrialized countries, have been developed and characterized. The efficacies of decoy ODNs specific for the transcription factors AP-1, NFAT and NF-IL6, have been demonstrated in neonatal rat heart muscle cells and fibroblasts. In addition, in first basic experiments the sonoporation technique was identified as an application method suitable for humans, which is a prerequisite for their practical utilization in novel therapies.

Latest results can be found in detail in the descriptions of the subprojects.

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