Abstract

Background: Alpha-synuclein (α-SN) is the central protein in synucleinopathies including Parkinson's disease. Nevertheless, the molecular mechanisms through which α-SN leads to neuronal death remain unclear. Methods: To elucidate the relationship between α-SN and apoptosis, some indicators of the intrinsic and extrinsic apoptotic cell death were assessed in normal and a stable HEK293T cell line expressing firefly luciferase after transfection with the wild-type (WT) and A53T mutant α-SN. Results: Opposite to WT-α-SN, overexpression of A53T-α-SN resulted in enhanced expression of almost two fold for RIPK1 (93.0 ), FADD (45 ), Caspase-8, and Casp-9 activity (52.0 ) in measured time. Transfection of both WT-α-SN and A53T-α-SN showed an increase in the Casp-3/Procasp-3 ratio (WT: 60.5 ; A53T: 41.0 ), Casp-3 activity (WT: 65.0 ; A53T: 20.5 ), and a decrease in luciferase activity (WT: 50 ; A53T: 34.8 ). Overexpression of A53T-α-SN brought about with more cell death percentage compared to WT-α-SN within 36 h. No significant alteration in cytochrome c and reactive oxygen species release into cytosol were observed for both WT-α-SN and A53T-α-SN. Conclusion: Altogether, these findings highlight the link between disease related mutants of α-SN (like A53T-α-SN) in triggering of RIPK1-dependent extrinsic apoptotic pathway in cell death during neurodegeneration. © 2023