Giant mitochondria distinct from enlarged mitochondria in secretory and ciliated cells of gerbil trachea and bronchioles

Abstract

Numerous mitochondria ranging from slightly larger than normal to several micrometers in diameter (giant) were found in about one-half the serous secretory cells in the surface epithelium of the normal gerbil trachea and proximal bronchi. Tracheal serous cells of mice also were found to contain numerous giant mitochondria. Clara cells of gerbil bronchioles contained abundant giant mitochondria in addition to normal tubular mitochondria and the second population of enlarged spherical mitochondria that have been described in Clara cells of several genera. In contrast, mouse Clara cells revealed the normal tubular and the enlarged spherical mitochondria but no giant mitochondria. A survey of a number of cell types in gerbils failed to disclose hypertrophied mitochondria outside tracheobronchial surface epithelium and bronchioles. The mitochondrial enlargement resulted from an increase of matrix but not cristae. The expansion of matrix displaced the relatively sparse cristae into small collections compressed against the outer membrane. The prevalence of giant mitochondria and of granular endoplasmic reticulum is similar among cells, and these two organelles are codistributed within cells. The megamitochondria and granular reticulum occupy a central stratum, whereas normal mitochondria occur in the apical and basal regions. The giant mitochondria are considered related to a normal biologic activity that is characteristic of respiratory tract epithelium of mice and gerbils selectively and is more prominent in secretory cells than in ciliated cells.

Effects of the common polymorphism in the human aldehyde dehydrogenase 2 (ALDH2) gene on the lung

“…As ALDH2 is a mitochondrial enzyme whose deficiency augments oxidative stress [12, 13], we examined the effect of its deficiency on the mitochondrial morphology in airway epithelial cells, using TEM. In the tracheas of WT adult mice, the previously described morphological differences between the mitochondria in club and ciliated cells were observed (i.e., fewer cristae and expanded matrix in club cells) [35, 36]. In this study, we detected the presence of a previously unknown minor population of “abnormal” mitochondria, which showed near complete lack of cristae and a marked decrease in matrix density in all groups (Fig.…”

“…Morphological differences between the mitochondria of club cells and ciliated cells have been described and are attributed to the high energy requirement of ciliated cells, resulting in their mitochondria having more cristae and a scanty matrix [35, 36]. In contrast, pathological conditions like hypoxia or increased oxidative stress result in “reduced-density” of the mitochondrial matrix [37, 38].…”

Dynamics of mitochondria in living cells: Shape changes, dislocations, fusion, and fission of mitochondria

“…The dearth of cristae and an abundant matrix argue for a low respiratory activity. Their functional significance is totally unclear (Spicer et al, 1990). Coexistence of giant, mostly cylindrically shaped, randomly distributed mitochondria and "small, normal" mitochondria localized in rows between myofibrils of adult cardiomyocytes is well established.…”

Giant mitochondria in the retina cone inner segments of shrews of genus Sorex (Insectivora, Soricidae)

“…This type of mitochondria has been observed in vertebrate cells in several pathological studies (Feldmann et al, 1977;Matias et al, 1991;Papadimitriou and Drachenberg, 1994), and has been experimentally produced (see reviews by Tandler and Hoppel, 1986;Hoppel and Tandler, 1993). Although their occurrence is mostly related to nutritional deficiency (Lloreta-Trull and Serrano, 1998), they have also been observed in apparently healthy, untreated cells (Slautterback, 1965;Grodums, 1977;Murakoshi et al, 1985;Marrero et al, 1987;Spicer et al, 1990;Tyler, 1992;Tandler et al, 1997). In particular, in mammalian retina, megamitochondria have been reported only in the ellipsoid of cones in two Scandentia: the common tree shrew (Tupaia glis) (Samorajski et al, 1966) and the northern tree shrew (Tupaia belangeri) (Kü hne, 1983;Foelix et al, 1987;Knabe and Kuhn, 1996).…”