FIGURE 3.

Reconstitution of AP-3 function in AT2 cells restores lamellar body PRDX6 and normalizes lung phospholipid homeostasis in pearl mice. pearl mice expressing the Ap3b1 transgene from an SP-C promoter (TG+) and transgene negative (TG−) littermates were compared with WT and genetically unmanipulated pearl mice (8–10 weeks old). A, representative immunoblots for PRDX6, SP-B, and GAPDH using AT2 lysates (20 μg each) and lamellar body fractions (25 μg each) from WT, pearl, TG+, and TG− mice. B, immunolocalization of PRDX6 in TG+ and TG− isolated alveolar type 2 cells after depletion of cytosolic constituents, using LAMP1 immunostaining to identify lamellar bodies (representative of two experiments; lamellar body noted by white arrow). C, phospholipase A₂ activity measured in lamellar bodies from TG− and TG+ mice (n = 3, mean ± S.E.). D, total phospholipid measured in lamellar bodies from TG− and TG+ mice (n = 3; mean ± S.E.). E and F, total phospholipid (PL), total PC, and total DSPC were measured in total lung tissue (E) and bronchoalveolar lavage fluid (F) from TG− and TG+ mice (n = 3 mice of each genotype, mean ± S.E.).