Figure 2

Effect of JNK inhibition on fetal alveolar interstitial fibroblasts (AIF) in hyperoxia. AIF were exposed to 21% up to 95% O2 over 24 h and 48 h, and cell proliferation was assessed by thymidine uptake (2A). Total and P-JNK were assessed (2B) and P-JNK staining was confirmed by immunocytochemistry (2C). Use of JNKi (CEP-1347) blocked the hyperoxia-induced decrease in lipid droplet staining (red fluorescence) and an increase in α-SMA staining (green fluorescence), two key markers of AIF-to-MYF transdifferentiation (2D) and diminished P-JNK (2E). Use of JNKi (SP600125) diminished P-JNK (2F) and blocked the hyperoxia-induced decrease in peroxisome proliferator-activated receptor γ (PPARγ) and adipocyte differentiation-related protein (ADRP) levels (2G), and the accompanying increase in fibronectin and LEF-1 levels (2H). O2: oxygen; JNKi: JNK inhibitor (SP600125 for A549 and AIFs, CEP-1347 for AIFs). All values represent a minimum of 4 measurements in each group and all figures are illustrative of a minimum of 4 experiments. *P < 0.05, **P ≤ 0.02, #P ≤ 0.01.