Figure 7.
Estrogen reduces Aβ-induced JNK activation. A, Neuron cultures were treated with 10 nm E2 for the indicated times and then assessed by Western blot with phospho-JNK (p-JNK) (top panel) and pan-JNK (bottom panel) antibodies. B, Blots were quantified by band densitometry for both the 54 kDa (black bars) and 46 kDa (gray bars) JNK forms. C, D, E2 reduces Aβ-induced JNK activation, as shown by both representative Western blots (C) and densitometric quantification of blots (D), in neuron cultures that were pretreated with 10 nm E2 for 60 min, followed by exposure to 25 μm Aβ25–35 for the indicated times. E, F, Representative Western blots probed with phospho-JNK (top panel) and pan-JNK (bottom panel) antibodies (E) and densitometric quantification of blots (F) show that pretreatment of neuron cultures with 1 μm ICI 182,780 for 60 min attenuates the inhibitory effect of 10 nm E2 treatment on JNK phosphorylation induced by exposure to 25 μm Aβ25–35 for 6 h. G, H, The JNK inhibitor SP600125 reduces Aβ-induced JNK activation, as shown by representative Western blots (G) and densitometric quantification of blots (H) from lysates of neuron cultures that were pretreated with 100 nm SP600125 for 60 min, followed by exposure to 25 μm Aβ25–35 for the indicated times. All experiments were repeated in three or more independent culture preparations. Data show mean phospho-JNK:total JNK ratios, normalized to the vehicle control condition. *p < 0.01 relative to matched Aβ25–35 condition at the same time point; #p < 0.01 relative to vehicle control (Ctrl) condition.