FIG 4.

ER stress stimulates JAK1-dependent STAT3 activation. Astrocytes (A) or the pancreatic β-cell line INS832/13 (C) was treated with Thaps (1 μM) for the indicated times followed by immunoblotting. (B) NPCs were treated with the indicated concentrations of Thaps for 2 h. (D) Astrocytes were treated with Thaps (1 μM, 1 h) in the absence or presence of the pan-JAK inhibitor P6 (0.5 μM) or the JAK1/2 inhibitor AZD1480 (1.0 μM), followed by immunoblotting for P-STAT3, STAT3, P-JAK1, and JAK1. (E) Astrocytes were treated with OSM (0.5 ng/ml) for 15 min in the presence of the indicated concentrations of the JAK1 inhibitor AZ-JAK1, followed by immunoblotting. (F) Astrocytes were treated with Thaps (1 μM) for the indicated times in the absence or presence of AZ-JAK1 (1.0 μM) followed by immunoblotting for P-STAT3 and STAT3. (G) Astrocytes were transfected with control or p65 siRNA (50 pmol/ml) for 72 h. Cells were then treated with Thaps (1 μM) for the indicated times followed by immunoblotting. (H) Astrocytes were pretreated (1 h) with cycloheximide (20 μg/ml) and then treated with Thaps (1 μM) for the indicated times, followed by immunoblotting and ELISA. (I) Astrocytes were treated with OSM (1 ng/ml) for the indicated times in the absence or presence of Thaps (1 μM, 30-min pretreatment) followed by immunoblotting. Data are the averages ± SD from 2 independent experiments.