Figure 2.

Oxidative stress from asbestos or H₂O₂ induces alveolar epithelial cell (AEC) ER stress as assessed by protein expression of IRE-1 and XBP-1 (spliced). (A) A549 cells were exposed to amosite asbestos (5–25 μg/cm²) or H₂O₂ (20–50 μM) for 1 hour, and then IRE-1 protein expression was assessed by Western blot analysis (blot is representative of four separate experiments). (B) Rat alveolar epithelial type (AT) 2 cells were exposed to amosite asbestos (25 μg/cm²), H₂O₂ (20 μM), or thapsigargin (Thap; 80 μM) for 1 hour, and then IRE-1 protein expression was assessed by Western blot analysis (representative blot of eight separate experiments). (C) A549 cells were exposed to amosite asbestos (5–25 μg/cm²) or H₂O₂ (20 μM) for various periods of time, and then XBP-1 spliced protein expression was assessed by Western blot analysis (blot is representative of six separate experiments). *P < 0.05 versus control.