Mitochondrial leader sequence-plasmid DNA conjugates delivered into mammalian cells by DQAsomes co-localize with mitochondria

In the last decade the increase in therapeutic strategies aimed at mitochondrial targets has resulted in the need for novel delivery systems for the selective delivery of drugs and DNA into mitochondria. In this study, we have continued our efforts towards the development of the first mitochondriotropic drug and DNA delivery system (DQAsomes). Prepared from derivatives of the self-assembling mitochondriotropic bola-amphiphile dequalinium chloride, these vesicles bind and transport DNA to mitochondria in living mammalian cells where upon they have been shown to release the DNA on contact with mitochondrial membranes. We present data to demonstrate that oligonucleotides as well as plasmid DNA conjugated to a mitochondrial leader sequence (MLS) co-localize with mitochondria when delivered into mammalian cells by DQAsomes. In contrast to a commercially available DNA delivery vector, our vesicles appear to have a pronounced specificity for mitochondria. Further, the data strongly suggest that linear conjugates might be better suited to delivery into mitochondria and that in the absence of a mitochondria specific vector, the presence of a MLS-peptide conjugated to the DNA is alone not sufficient to direct the accumulation of DNA at mitochondria.