FIGURE 2.

Reduced VDR expression and activated parthanatos in MPP⁺-induced SH-SY5Y cells. SH-SY5Y cells were treated with different concentrations of MPP⁺ for 24 h. Cell viability was assessed by CCK8 assay (A). VDR expression was detected by western blotting (B) and quantified (C). SH-SY5Y cells were pretreated with different concentrations of Z-VAD-FMK for 1 h before 100 μM MPP⁺ treatment, then CCK8 assay assessed cell viability (D). Compared with control, ***p < 0.001; compared with MPP⁺ group, ^##p < 0.01, ^###p < 0.001, n = 5. SH-SY5Y cells were pretreated with different concentrations of Nec-1 for 4 h before 100 μM MPP⁺ treatment, then CCK8 assay assessed cell viability (E). Compared with control, ***p < 0.001; compared with MPP⁺ group, ^#p < 0.05, n = 5. SH-SY5Y cells were treated with different concentrations of MPP⁺ for 24 h. PAR and PARP1 expression were detected by western blotting (F) and quantified (G). The cytoplasmic and nuclear proteins were extracted separately. AIF expression was detected by western blotting (H) and quantified (I). Data are shown as mean ± SEM, based on three independent experiments, *p < 0.05, **p < 0.01, ***p < 0.001.