Figure 5.
Estrogen regulation of Bcl-w and Bim expression is ER dependent. A, C, Representative agarose gels of RT-PCR products using bcl-w (A) or bim (C) primers show that the ER antagonist ICI 182,780 blocks E2 regulation of bcl-w and bim under basal conditions. Neuron cultures were pretreated with 1 μm ICI 182,780 for 60 min, followed by 10 nm E2 for 24 and 48 h, respectively. β-actin served as an internal control. B, D, Representative agarose gels of RT-PCR products using bcl-w (B) or bim (D) primers show that the ER antagonist ICI 182,780 blocks E2 inhibition of Aβ-induced changes in bcl-w and bim expression. Neuron cultures were pretreated with 1 μm ICI 182,780 for 60 min, followed by 10 nm E2 for 60 min, and then exposed to 25 μm Aβ25–35 for 24 and 48 h. β-actin served as an internal control. E, ER dependence of E2 bcl-w and bim regulation was extended to protein expression using Western blots. A representative Western blot shows Bcl-w (top panel), Bim (middle panel), and β-tubulin (bottom panel) expression in lysates from neuron cultures that were pretreated with 1 μm ICI 182,780, followed 60 min later with 10 nm E2 treatment, and then 60 min later exposed to 25 μm Aβ25–35 for 48 h. F, G, Relative protein levels of Bcl-w (F) and Bim (G) were determined by densitometric scanning of Western blots from four independent experiments. Data show mean (+SEM) percentages of control values. *p < 0.01 relative to E2-treated condition; #p < 0.01 compared with E2 plus Aβ25–35 treatment.