Fig. 7: The pro-regeneration and anti-fibrotic effects of TRβ activation depended on KLF2 in mice.

a Schematic of the Klf2 Cre-loxp knockout site in AT2 cells and experimental design. b Hydroxyproline content in the right lung (n = 6, 6, 9, 6, 9, 6). c, d Protein concentration (n = 8, 7, 9, 7, 9, 7) and WBC numbers (n = 6, 6, 8, 7, 8, 7) in BALF. e Immunoblotting for COL1A1 and AT1 cell markers in lung homogenates. f Representative images of trichrome staining. Scale bar of whole sections, 2 mm; scale bar of 10 × images, 100 μm. g, h Representative IF staining and quantification of KRT8⁺ cells in AT2-KLF2-KO mice (n = 5). Arrows show the KRT8⁺ cells. Scale bars, 50 μm. i, j The mRNA levels of AT1 cell markers in the lung of AT2-Klf2-KO mice at the differentiation phase in the PNX model. The value of n indicates biologically independent samples (b–d, j). Data of different sections from three biologically independent mice (h). Similar results were repeated in two biologically independent experiments. Throughout, data are mean ± SEM. P-values were obtained by one-way ANOVA with Turkey’s multiple comparison tests.