Nanoparticules d’ADN fonctionnalisées par des peptides ligands de la dynéine pour l’amélioration de leur trafic intracellulaire. – NADYN

Non viral gene delivery systems have benefited from considerable development over the last two decades and constitute a very promising alternative to viral vectors for gene therapy. The synthetic vectors have many advantages in terms of biosecurity, ability to carry a gene of unlimited size, low cost and ease of production as compared to viral ones. However, they present several drawbacks which are related to efficiency, specificity and bioavailability. These limitations are concerned with (i) their size, (ii) cationic surface charge, which is responsible for un-specific interactions with biofluid components as well as with un-targeted tissues and cells, and/or (iii) the various physiological obstacles to come across for penetrating and delivering the gene into the cytoplasm then into the nucleus of the target cells. More recently, and to overcome some of these barriers, a new generation of synthetic gene delivery systems often named as « synthetic viruses » has been designed. These vectors are multi-component, multi-functional supramolecular assemblies whose functions and properties are reminiscent of those of viruses, which served as model for their design : (i) nanometric size (' 100 nm), (ii) cell tropism and specificity, (iii) poor reticulo-endothelial recognition and uptake, (iv) cytoplasmic delivery, (v) nucleus tropism and delivery. Despite these improvements, the DNA nanoparticles are most frequently taken up into cells by a clathrin-dependent endocytotic pathway. As a consequence, they are sequestered into early endosomes from which they must escape rapidly in order to avoid enzymatic degradation of the DNA cargo and to reach intact the nucleus. In addition, several studies have shown that DNA nanoparticles upon direct injection into the cytosol, which is a very viscous medium, are almost not moving and do not migrate to the nucleus. The intracellular traffic to the nucleus and the nuclear uptake are among the most limiting steps for an efficient expression of the genes introduced by synthetic vectors. Our project is aimed at improving these steps by the development of DNA nanoparticles labelled with ligands of cytoplasmic dyneins which are molecular motor proteins associated to the cytoskeleton microtubular network. Thus, like viruses, one can benefit from the retrograde transport (from the periphery to the nucleus) along the microtubules to the MTOC (microtubule transport organizing center) for carrying actively the DNA nanoparticles in close proximity to their final destination (i.e. the nucleus). This should facilitate the nuclear delivery of a therapeutical gene and its expression into the therapeutical protein encoded by the gene. If some attempts have been described in literature, our approach has never been explored to the best of our knowledge.