A Dual-Ligand Liposomal System Composed of a Cell-Penetrating Peptide and a Mitochondrial RNA Aptamer Synergistically Facilitates Cellular Uptake and Mitochondrial Targeting

It has been reported that the use of mitochondrial RNA aptamers including RNase P (RP) results in the selective mitochondrial delivery of endogenous and exogenous RNAs. The issue of whether these aptamers would be useful ligands for the mitochondrial targeting of a nanoparticle has not been demonstrated to date because nanocarriers modified with these RNA aptamers are insufficiently internalized by cells. We report here on the development of a dual-ligand liposomal system composed of octaarginine (R8), a device that enhances cellular uptake, and an RP aptamer for mitochondrial targeting to permit a nanocarrier to be efficiently delivered to mitochondria. Surprisingly, the cellular uptake of the R8-modified nanocarrier was facilitated by modification with an RP aptamer. The optimal composition of a nanocarrier needed for efficient cellular uptake and mitochondrial targeting was determined. In a confocal laser scanning microscopy analysis, the dual-ligand–modified nanocarrier was found to result in effective mitochondrial targeting through an ATP-dependent pathway and was much more effective than a single-ligand R8-modified nanocarrier. This is the first report of the regulation of intracellular trafficking by a mitochondrial RNA aptamer–modified nanocarrier system.