Fig. 1.

FOXO induces PDGFRA. (A) Activation of FOXO signaling upon serum deprivation up-regulates PDGFRA. SH-SY5Y cells were exposed to serum-free SHTE medium for the indicated times. Total RNA and protein were then extracted. Relative levels of PDGFRA, PDGFRB, FOXO1, FOXO3, and FOXO4 mRNA were determined by QRT-PCR (Left). The protein lysate were subjected to Western blotting with antibodies against the indicated proteins (Right). (B) PDGFRA protein stability remains unchanged upon serum-free SHTE treatment. SH-SY5Y cells either untreated or treated with serum-free SHTE for 8 h were chased with CHX (100 μM). Total cell lysates were prepared at the indicated times after the addition of CHX and analyzed by Western blotting using anti-PDGFRA and β-Actin antibodies. (C) Transcription inhibitor Act D abolishes the induction of PDGFRA upon serum-free SHTE exposure. SH-SY5Y cells were pretreated with Act D (0.5 μg/mL) or DMSO for 30 min, and then cultured in serum-free SHTE medium in the presence of Act D or DMSO for 8 h. The levels of PDGFRA mRNA and protein were assayed by QRT-PCR (Left) or Western blotting (Right). (D) Depleting FOXO members attenuates PDGFRA expression. SH-SY5Y cells expressing control shRNA or TKD shRNA were treated with SHTE, and then harvested at the indicated time points for protein and RNA analyses.