The Effects Of Different Mechanisms Of Cytotoxic Drugs On The α-synuclein Expression In The Human Oligodendrogiial Cell Line

Background:Multiple system atrophy (MSA) is a disease of unknown etiologyand pathogenesis that is likely caused by the interaction of multiplegenetic and environmental factors. Glial cytoplasmic inclusion (GCI) is apathological hallmark of MSA. The main component of GCI isα-synuclein, which thought to play a crucial role in the pathogenesis ofMSA. The source of oligodendroglial α-synuclein and its accumulation inMSA is yet unknown. Through in vitro study, the aim of this study is toinvestigate whether some environmental toxins implicated in theaccumulation of α-synuclein in the human oligodendroglial cell line as apossible mechanism for GCI formation in MSA.Methods:We use the human oligodendroglial cell line (MO3.13). Mo3.13cellswere treated with the toxins3-nitropropionic acid (3-NP),3-methyladenine (3-MA) or H2O2. The cell viability was determined byMTT assay and then the appropriate concentration of each toxin wasdetermined. Under this concentration, MO3.13cells were treated with thethree different toxins for24hours and the positive group was selected bywestern blot analysis. After that, the change in the expression ofα-synuclein protein in different concentration of positive drug wasdetermined by western blot. In addition, we also examined the change in the SNCA mRNA with different concentration of this toxin usingquantitative real-time PCR. Finally, the change in α-synucleinimmunoreactivity was measured.Result:1. The viability of the cells decreased in a dose-dependent mannerwith an increase in the toxin concentrationfor all three toxins (P<0.05).2. Among three different toxic insults,3-NP treated cells showed asubstantial increase (34%) in α-synuclein protein expression. Thedecreased cell viability with3-NP was related to an increase inintracellular α-synuclein protein. There is no difference on theα-synuclein expression in3-MAor H2O2compared with control.3. Further experiments using western blot and quantitative real-timePCR showed that the treatment with3-NP for24hours increased theexpression of α-synuclein protein and SNCA mRNA in a dose-dependentmanner (P<0.05). Immunocytochemistry results also revealed that theα-synuclein immunoreactivity was increased in the3-NP treated cellscompared to the non-treated control.Conclusion:1．3-NP、3-MA、 H2O2can inhibit MO3.13oligodendrocyteproliferation, are toxic to cells. The decreased cell viability with3-NPwas related to an increase in intracellular α-synuclein protein.2.3-NP, the irreversible inhibitor of mitochondrial complex II can increased the expression of α-synuclein protein and SNCA mRNA inMO3.13.3. Mitochondrial dysfunction associated with the increase inα-synuclein expression and may be involved in the pathogenesis of MSA.