Kisspeptin-10 Rescues Cholinergic Differentiated SHSY-5Y Cells from α-Synuclein-Induced Toxicity In Vitro

The neuropathological substrate of dementia with Lewy bodies (DLB) is defined by the inextricable cross-seeding accretion of amyloid-beta (A beta) and alpha-synuclein (alpha-syn)-laden deposits in cholinergic neurons. The recent revelation that neuropeptide kisspeptin-10 (KP-10) is able to mitigate A beta toxicity via an extracellular binding mechanism may provide a new horizon for innovative drug design endeavors. Considering the sequence similarities between alpha-syn's non-amyloid-beta component (NAC) and A beta's C-terminus, we hypothesized that KP-10 would enhance cholinergic neuronal resistance against alpha-syn's deleterious consequences through preferential binding. Here, human cholinergic SH-SY5Y cells were transiently transformed to upsurge the mRNA expression of alpha-syn while alpha-syn-mediated cholinergic toxicity was quantified utilizing a standardized viability-based assay. Remarkably, the E46K mutant alpha-syn displayed elevated alpha-syn mRNA levels, which subsequently induced more cellular toxicity compared with the wild-type alpha-syn in choline acetyltransferase (ChAT)-positive cholinergic neurons. Treatment with a high concentration of KP-10 (10 mu M) further decreased cholinergic cell viability, while low concentrations of KP-10 (0.01-1 mu M) substantially suppressed wild-type and E46K mutant alpha-syn-mediated toxicity. Correlating with the in vitro observations are approximations from in silico algorithms, which inferred that KP-10 binds favorably to the C-terminal residues of wild-type and E46K mutant alpha-syn with CDOCKER energy scores of -118.049 kcal/mol and -114.869 kcal/mol, respectively. Over the course of 50 ns simulation time, explicit-solvent molecular dynamics conjointly revealed that the docked complexes were relatively stable despite small-scale fluctuations upon assembly. Taken together, our findings insinuate that KP10 may serve as a novel therapeutic scaffold with far-reaching implications for the conceptualization of alpha-syn-based treatments.