Figure 2. Activation of Notch Signaling in AT2 at Onset of Alveolar Epithelial Repair after PA-Induced Lung Injury.

(A) Lung injury was induced by intratracheal (i.t.) injection of PA bacteria.

(B) DAPI staining of lung sections prepared at different stages after i.t. injection of PA. Cell density was calculated as the number of DAPI-positive cells versus the area of lung tissue. The relative cell density of each time point compared with the control was plotted. The relative cell density corresponds to different phases (inflammation, early and later repair) during the injury repair process. (C–H) AT2 were isolated from uninjured and 3-day post-injury mice and processed for qRT-PCR for expression of Dlk1 (C), Notch 1 (D), Notch 2 (E), Jagged 1 (F), Hes1 (G), and NRAPP (H).

(I) Tomato⁺ AT2 were isolated by flow-sorting from SPC-Tomato mice for western blot analysis. The intensities of the western blot bands were quantified using ImageJ. The data show an increased level of NICD in AT2 isolated from 3-day post-injury mice compared with uninjured mice when normalized to the β-actin loading control.

Bar graph data are presented as mean ± SE; n ≥ 3. *p < 0.05, **p < 0.01. See also Figure S2.