Physicochemical characterization and targeting performance of triphenylphosphonium nano-polyplexes

Mitochondrial gene therapy can be seen as a promising tool and a revolutionary approach towards mitochondrial diseases arising from mitochondrial DNA mutations. To pursue this goal, the mitochondria-targeted polycation polyethylenimine (PEI)/triphenylphosphonium (TPP) conjugate has been used to complex and condense both GFP or ND1 encoded plasmid DNA (pDNA) aiming at the formation of suitable vectors for mitochondrial gene therapy. The properties of pDNA based TPP-polyplexes have been addressed and appear to be valuable for gene delivery applications. In vitro studies using fluorescent pDNA demonstrated the internalization of the developed carriers and mitochondria targeting. Evidences of gene expression into mitochondria are also reported. Following this achievement, significant levels of both mitochondrial recoded GFP and ND1 proteins were quantified. This work represents a great step towards effective mitochondria-targeting gene delivery and functional protein expression, providing a significant contribution in mitochondrial gene therapy field.