Figure 2. TRPC1 mediates SOCE in SH-SY5Y cells, and MPP⁺ selectively decreases TRPC1 expression/function.

(A) SH-SY5Y cells were treated with MPP⁺ (500 μM) for 12 hours. RNA was extracted, and quantitative RT-PCR was performed. Values represent mean ± SD from at least 3 independent experiments. *P < 0.05 versus untreated control. TRPC1 was evaluated after 15 cycles, whereas other TRPCs required at least 25 cycles. (B) Cells were treated with vehicle control or MPP⁺ and lysed, and proteins were subjected to SDS-PAGE followed by Western blotting with the indicated antibodies. Membranes were reprobed with anti–β-actin antibody to confirm equal loading. (C) Quantification (mean ± SD) of individual proteins from 3 or more independent experiments. Relative expression of each individual proteins was normalized to β-actin. *P < 0.05 versus untreated control. (D and E) Immunoprecipitation with anti-STIM1 antibody of lysates from control or MPP⁺-treated cells with or without Tg. Immunoblotting was performed using anti-TRPC1, -Orai1, and -STIM1 antibodies. (E) Brain lysates from control and PD samples were subjected to SDS-PAGE and immunoblotted with the respective antibodies. (F) Paraffin-embedded sections of postmortem human SNpc samples obtained from control and PD patients were immunostained using TRPC1 and TH antibodies. Original magnification, ×40.