Blood plasma from patients with Parkinson's disease and multiple system atrophy enhances ability of α-synuclein aggregates to destroy cell membrane / 中华神经医学杂志

ABSTRACT

Objective:To explore the role of α-synuclein (α-Syn) in pathogenesis of Parkinson's disease (PD) and multiple system atrophy (MSA) by observing the ability of α-Syn aggregates incubated with PD and MSA patients' plasma to destroy cell membrane.Methods:Peripheral blood samples were collected from 5 PD patients and 5 MSA patients diagnosed in Department of Neurology, Affiliated Hospital of Guilin Medical University from January 2018 to January 2022, as well as 5 physical examination healthy control subjects (HCs) during the same period. The α-Syn was dissolved in 0.01 mol/L PBS and then incubated with PBS, and plasma from HCs, PD patients and MSA patients at 37 ℃ for 4 d, respectively (named as PBS group, HC group, PD group and MSA group). Small unilamellar vesicles (SUVs) containing calcein were prepared with acidic phospholipid, 1-palmityl-2-oleoyl-Sn-glycerol-3-phospho-L-serine (POPS), by membrane dispersion-ultrasonic method; the particle size and morphology of SUVs were analyzed by Malvern Zetasizer Nano ZS and transmission electron microscope. SUVs and human neuroblastoma cells (SH-SY5Y) were treated with different concentrations of α-Syn aggregates (0.5, 1.0, 2.0, 4.0, 8.0 and 16.0 μmol/L). The abilities of α-Syn aggregates formed under different conditions to destroy liposomes and cell membrane were evaluated by measuring the calcein relative release and intracellular calcein fluorescent value after dialysis.Results:(1) Destructive effect of α-Syn aggregates on SUVs: calcein induced by α-Syn aggregates in each group increasingly released with the increase of protein concentration; at protein concentration of 8 μmol/L, the calcein released from SUVs in PD and MSA groups was significantly higher than that in PBS and HC groups, and the calcein released from SUVs in MSA group was further significantly higher than that in the PD group ( P<0.05). (2) Destructive effect of α-Syn aggregates on cell membrane in SH-SY5Y: the calcein fluorescent value in each group decreased with the increase of protein concentration; at protein concentration of 8 μmol/L, the intracellular calcein fluorescent value in PD and MSA groups were significantly decreased compared with that in PBS and HC groups ( P<0.05); the intracellular calcein fluorescent value in MSA group was further significantly decreased compared with that in PD group ( P<0.05). (3) Effect of α-Syn aggregates on SH-SY5Y cell survival: at protein concentration of 8 μmol/L, the viability of SH-SY5Y cells in each group decreased obviously; PD and MSA groups had significantly decreased cell viability compared with PBS and HC groups ( P<0.05); and the viability in MSA group was further statistically decreased compared with that in PD group ( P<0.05). Conclusion:The ability of α-Syn aggregates incubated with PD and MSA patients' plasma to destroy cell membrane is greater than that with HCs' plasma, especially those with MSA patients' plasma.