Figure 5: Altered mitochondrial structure in airway epithelial cells of Stard7^epiΔ/Δ mice.

(a) Airway sections obtained from lungs of 4-month-old Stard7^f/f and Stard7^epiΔ/Δ mice were examined by electron microscopy. Stard7^epiΔ/Δ mice exhibited mitochondrial abnormalities in bronchiolar epithelial cells, including poorly defined mitochondrial matrix, reduction in number of cristae, increased lipid accumulation juxtaposed to outer limiting membrane of mitochondria (white arrow), formation of mitochondrial blebs (black arrow), and mitochondrial disintegration. Formation of an isolation membrane (small arrow) encircling a mitochondria (cross) and autophagosomes (asterisk) containing mitochondrial fragments were pronounced in some Stard7^KO cells. (b) Electron micrographs of mitochondria in ciliated bronchiolar epithelial cells, acquired from 4-month-old Stard7^f/f and Stard7^epiΔ/Δ mice, were used for morphometric analysis. There was a significant reduction of mitochondrial cristae in ciliated bronchiolar epithelial cells of Stard7^epiΔ/Δ mice compared to Stard7^f/f mice, **p < 0.001; MT = mitochondria.