Figure 2 – Stat3 regulates key pathways in alveolar epithelial regeneration.

(A) IL-6 is undetectable in uninjured lungs. Levels of IL-6 in BAL fluid peak at 24h after acid-induced lung injury (n=3 mice per time point). (B & C) C57BL/6 mice that underwent acid-induced lung injury demonstrate activated pSTAT3 in AT2 cells (p=2.9x10⁻⁵ for 9 days post infection vs uninjured). There was minimal phosphorylated STAT3 in AT2 cells of uninjured mice (n= 4 mice per group). (D & E) Human samples with diffuse alveolar damage had increased AT2 specific pSTAT3 (p=1.8x10⁻⁶) that was not present in uninjured samples (n=4 patients per group). (F & G) Unbiased pathway analyses demonstrated newly accessible STAT3 binding sites adjacent to genes that control key biological mechanisms including proliferation and migration. For panels (A) (C) and (E), data is shown as the mean +/− SEM. Statistical significance was determined with a two-tailed Student’s t-test (C & E). Scale bars 50μm (B, D) and 25μm (B, D).