Design and Synthesis of Fluorescent Methylphenidate Analogues for a FRET-Based Assay of Synapsin III Binding

We previously described synapsin III (Syn III) as a synaptic phosphoprotein that controls dopamine release in cooperation with α-synuclein (aSyn). Moreover, we found that in Parkinson's disease (PD), Syn III also participates in aSyn aggregation and toxicity. Our recent observations point to threo-methylphenidate (MPH), a monoamine re-uptake inhibitor that efficiently counteracts the freezing-gait characteristic of advanced PD, as a ligand for Syn III. We have designed and synthesised two different fluorescently labelled MPH derivatives, one with Rhodamine Red (RHOD) and one with 5-carboxytetramethylrhodamine (TAMRA), to be used for assessing MPH binding to Syn III by FRET. TAMRA-MPH exhibited the ideal characteristics to be used as a FRET acceptor, as it was able to enter into the SK-N-SH cells and could interact specifically with human green fluorescent protein (GFP)-tagged Syn III but not with GFP alone. Moreover, the uptake of TAMRA-MPH and co-localization with Syn III was also observed in primary mesencephalic neurons. These findings support that MPH is a Syn III ligand and that TAMRA-conjugated drug molecules might be valuable tools to study drug-ligand interactions by FRET or to detect Syn III in cytological and histological samples.     

Anionic liposomes for small interfering ribonucleic acid (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).LB accumulation is considered a causative factor of PD,which suggests that strategies aimed at reducing α-syn levels could be relevant for its treatment.In the present study,we developed novel nanocarriers suitable for systemic delivery of small interfering ribonucleic acid (siRNA) that were specifically designed to reduce neuronal α-syn by RNA interference.Anionic liposomes loaded with an siRNA-protamine complex for α-syn gene silencing and decorated with a rabies virus glycoprotein (RVG)-derived peptide as a targeting agent were prepared.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 their efficiency to induce gene silencing in these cells.Moreover,the nanocarriers were evaluated for their stability in serum.The RVG-decorated liposomes displayed suitable characteristics for future in vivo applications and successfully induced α-syn gene silencing in primary neurons without altering cell viability.Collectively,our results indicate that RVG-decorated liposomes may be an ideal tool for further studies aimed at achieving efficient in vivo α-syn gene silencing in mouse models of PD.     

Erratum to: Anionic liposomes for small interfering ribonucleic acid (siRNA) delivery to primary neuronal cells: Evaluation of alpha-synuclein knockdown efficacy

Nano Research - The name of the fourth author in the original version of this article was unfortunately wrongly written on the first page. Instead of Caitriona M. O’iscoll It should read...