Naked-gene transfer technology and somatic gene therapy approaches in adult and in utero

Direct intramuscular injection of 'naked' DNA in adult animals has been demonstrated to be a safe, efficient and economic method of in vivo gene transfer. The peculiar properties of this method, that has demonstrated wide margins of biological safety and may be used clinically in a way similar to conventional medicines, may contribute to a high margin of clinical Safety and patient acceptance in setting up gene therapy trials. The muscle offers several interesting features for gene therapy because it is abundantly represented in the body, it has a rich blood supply, and it is readily accessible for multiple gene administrations. The expression of genes in vivo in muscles has several types of potential applications. Muscle could be used as a 'platform' for the direct in vivo production and systemic delivery of homologous functional proteins. Moreover, direct intramuscular injection of antigen expressing (infectious agents or 'Tumor Specific Antigens') plasmid vectors induces specific, potent and complete immune response against the transgenic protein, through a complex mechanism which involves myofibers, plasmid prokaryotic sequences and dendritic cells (genetic vaccination). Our group is actively involved in projects covering different aspects of this method We have developed technical improvements to plasmid vectors both by protecting them from nuclease attack through chemical modifications of the DNA backbone, and by constructing specific expression vectors for drug delivery and/or genetic vaccination. We are successfully developing gene therapy approaches to dislipidemias through muscle chronic expression and systemic delivery of apolipoprotein E, and to B-lymphomas by genetic vaccination against the individual idiotypic determinants of tumor cells. Furthermore, we have exploiting with success the possibility of direct in utero gene transfer in fetal muscles, either to express therapeutic proteins, or to modulate immune response against non-self proteins, before the development of any fetal or newborn damage due to congenital or acquired defects.