Normalization of the endothelial AJ barrier by restoration of β-catenin expression after increased vascular permeability in FoxM1 CKO lungs. (A) Quantitative RT-PCR analysis of gene expression. After 2 d in culture, microvascular ECs isolated from WT or FoxM1 CKO mouse lungs were lysed for total RNA isolation. Non-EC cultures (fibroblasts) were also lysed for total RNA isolation. mRNA levels of the indicated genes were quantified by quantitative RT-PCR. Data are expressed as mean ± SD (error bars; n = 3 independent experiments). *, P < 0.01 versus WT-EC; #, P < 0.05 versus WT-EC. (B) Western blotting demonstrating decreased β-catenin expression in FoxM1 CKO lungs compared with WT lungs and restoration of β-catenin expression by liposome-mediated transduction of plasmid DNA expressing β-catenin. The experiment was performed three times with similar results. CKO, FoxM1 CKO. (C) Normalization of vascular junctional repair by restoration of β-catenin expression in FoxM1 CKO lungs. Plasmid DNA expressing β-catenin or empty vector were transduced in FoxM1 CKO lungs through i.v. injection of the liposome–DNA complex. WT mice transduced with empty vector DNA were used as controls. At 40 h after transduction, mice were challenged with a PAR-1 agonist peptide (i.v., 5 mg/kg BW). Lungs were isolated at 2 h after challenge and perfused for K_f,c measurement. Data are expressed as mean ± SD (error bars; n = 3–4 animals/group from three independent experiments). *, P < 0.05 versus either WT + vector, or CKO + β-catenin.