Figure 3. Loss of Fltp leads to constricted distal airways and cilia formation defects in the lung.
(A–C) Whole-mount lacZ stained and BABB cleared distal airways of left lung lobes at P60. Red lines show how diameters were measured. (A) FltpT2AiCre/+; R26R/+is used as control (Ctrl). (B and C) FltpZV/+ and FltpZV/ZV animals show constricted distal airways. (D) Average distal airway diameter of Ctrl animals is 132.25 µm (n = 4; 125 bronchi), of FltpZV/+ animals is 99.68 µm (n = 3; 90), and of FltpZV/ZV animals is 90.06 µm (n = 3; 95). (E–G and I–K) Immunohistochemistry on cryosections of lung distal airway epithelium combined with LSM analysis. (E and I) In Fltp+/+animals BBs project cilia at the apical surface. (F and J) In FltpZV/+ animals less and shorter cilia are detectable. (G and K) FltpZV/ZV animals often show absence of or shorter cilia at the apical surface. Note that only very few BBs are docked at the apical surface. (H and L) FltpZV/ZV animals show significant shorter cilia than Fltp+/+ animals. In total we examined n = 3 (81 cells) for Fltp+/+, n = 2 (22) for FltpZV/+, and n = 2 (93) for FltpZV/ZV P7 animals. For P30 we examined n = 3 (121 cells) for Fltp+/+, n = 3 (134) for FltpZV/+, and n = 2 (138) for FltpZV/ZV. BBs are marked by γ-Tubulin (γTub), cilia by acetylated-Tubulin (aT), cell membrane by β-Catenin (βCat), nuclei by DAPI, and nuclei of Fltp reporter expressing cells by GFP. Statistical analysis uses an one way ANOVA (**p = 0.0028; ***p < 0.0001 for (D) and *p = 0.0143; **p = 0.0025 for (H and L)). Error bars show the 95% confidence interval of the mean (D) and the standard error of the mean (H and L). Scale bars; 200 µm (A–C).