Anionic liposomes for siRNA delivery to primary neuronal cells: evaluation of Alpha synuclein knockdown efficacy

Alpha-synuclein (α-syn) deposition in Lewy bodies (LB) is one of the main neuropathological hallmarks of Parkinson's disease (PD). Of note, LB accumulation is considered as a causative factor for PD, thus suggesting that strategies aimed at reducing α-syn levels could be relevant for its treatment. In the present study, we set up novel nanocarriers suitable for systemic delivery of siRNA specifically designed to reduce neuronal α-syn by RNA interference. To this purpose, we prepared anionic liposomes, loaded with a complex of siRNA-protamine for α-syn gene silencing and decorated with a rabies virus glycoprotein (RVG)-derived peptide as a targeting agent. The nanoparticles were characterized for their ability to load, protect and deliver the functional siRNA to mouse primary hippocampal and cortical neurons as well as for their efficiency to induce gene silencing in these cells. . Moreover, the deriving nanocarriers were tested to evaluate their stability in serum. Of note, the RVG-decorated liposomes displayed suitable characteristics for future in vivo applications and were able to induce α-syn gene silencing in primary neurons, without altering cell viability. Collectively, our results indicate that RVG-decorated liposomes may represent an ideal tool for further studies aimed at achieving efficient α-syn gene silencing in vivo in mouse models of PD.