Sc 55510

1,25(OH)₂D₃ and 6-OHDA were purchased from Sigma-Aldrich (1,25(OH)₂D₃; 17936, 6-OHDA; H4381, Sigma-Aldrich, St. Louis, MO, USA). The following primary antibodies were used: rabbit antibody to tyrosine hydroxylase (TH) (NB300-109, 1:2000, Novus Biologicals, Littleton, CO, USA), rabbit antibody to GFAP (ab7260, 1:1000, Abcam, Cambridge, UK), rabbit antibody to CD31 (ab28364, 1:1000, Abcam, Cambridge, UK), mouse antibody to CD31 (#550274, 1:1000, BD biosciences, Franklin lakes, NJ, USA), rabbit antibody to VDR (ab3508, 1:1000, Abcam, Cambridge, UK), mouse antibody to P-gp (sc-55510, 1:1000, Santa Cruz, Dallas, TX, USA), mouse antibody to pS129-α-synuclein (#825701, Biolegend, San Diego, CA, USA), and mouse antibody to α-synuclein (BD-610787, BD Biosciences, Franklin lakes, NJ, USA).
The following secondary antibodies were used: biotin-conjugated goat antibody to rabbit IgG (cat# BA-1000, 1:1000, Vector Laboratories, Burlingame, CA, USA), Alexa fluor 568-conjugated donkey antibody to rabbit IgG (A10042, Invitrogen, Carlsbad, CA, USA), Alexa fluor 488-conjugated donkey antibody to mouse IgG (A21202, Invitrogen, Carlsbad, CA, USA), and Alexa Fluor 405-conjugated goat antibody to mouse IgG (A31553, Invitrogen).

Antibodies against alpha-tubulin (sc-8035) and MDR1 (sc-55510) were purchased from Santa Cruz, USA, whereas Horseradish peroxidase (HRP) labeled anti-mouse secondary antibody (1036–05) was purchased from Southern Biotech, USA. For immunoblotting, cells were collected in lysis buffer (100 mM NaCl, 50 mM Tris pH = 7.4, 1% Triton X supplemented with cocktails of phosphatase and protease Inhibitors) on ice, and cell lysates were cleared through centrifugation. Protein concentration was measured by Bradford assay and equal amounts of proteins (15 μg total for each sample) were loaded on 10% SDS-PAGE. Separated proteins were then transferred onto nitrocellulose membrane, followed by blocking with 5% skimmed milk for 1 hour at room temperature. Membranes were then incubated with respective primary antibodies overnight at 4°C. Next day, blots were washed with 1X PBST and incubated with HRP labelled anti-mouse secondary antibody for 1 hour at room temperature. Finally, blots were washed with 1X PBST, developed with enhanced chemiluminescence (ECL) reagent and visualized on BioRad ChemiDoc.

The IHC and TUNEL staining of FFPE tissue and its scoring system were performed, as described previously.^{4 (link)} The mouse primary antibodies used were as follows: PRKCE (1:200, sc-1681, Santa Cruz), MDR1/P-gp (1:200, sc-55510, Santa Cruz).