Journal
AMERICAN JOURNAL OF PHYSIOLOGY-LUNG CELLULAR AND MOLECULAR PHYSIOLOGY
Volume 285, Issue 1, Pages L189-L198Publisher
AMER PHYSIOLOGICAL SOC
DOI: 10.1152/ajplung.00253.2002
Keywords
alveolar epithelium; mitochondria; NADH dehydrogenase; manganese superoxide dismutase
Categories
Funding
- NHLBI NIH HHS [HL-57801] Funding Source: Medline
Ask authors/readers for more resources
Both NADH dehydrogenase (complex I) and aconitase are inactivated partially in vitro by superoxide (O-2(is approximately equal to)) and other oxidants that cause loss of iron from enzyme cubane (4Fe-4S) centers. We tested whether hypoxia-reoxygenation (H-R) by itself would decrease lung epithelial cell NADH dehydrogenase, aconitase, and succinate dehydrogenase (SDH) activities and whether transfection with adenoviral vectors expressing MnSOD (Ad.MnSOD) would inhibit oxidative enzyme inactivation and thus confirm a mechanism involving O-2.. Human lung carcinoma cells with alveolar epithelial cell characteristics (A549 cells) were exposed to <1% O-2-5% CO2 (hypoxia) for 24 h followed by air-5% CO2 for 24 h (reoxygenation). NADH dehydrogenase activity was assayed in submitochondrial particles; aconitase and SDH activities were measured in cell lysates. H-R significantly decreased NADH dehydrogenase, aconitase, and SDH activities. Ad. MnSOD increased mitochondrial MnSOD substantially and prevented the inhibitory effects of H-R on enzyme activities. Addition of alpha-ketoglutarate plus aspartate, but not succinate, to medium prevented cytotoxicity due to 2,3-dimethoxy-1,4-naphthoquinone. After hypoxia, cells displayed significantly increased dihydrorhodamine fluorescence, indicating increased mitochondrial oxidant production. Inhibition of NADH dehydrogenase, aconitase, and SDH activities during reoxygenation are due to excess O-2. produced in mitochondria, because enzyme inactivation can be prevented by overexpression of MnSOD.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available