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Differences in electron transport potential, antioxidant defenses, and oxidant generation in young and senescent fetal lung fibroblasts (WI‐38)
Author(s) -
Allen R.G.,
Tresini Maria,
Keogh Bart P.,
Doggett David L.,
Cristofalo Vincent J.
Publication year - 1999
Publication title -
journal of cellular physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.529
H-Index - 174
eISSN - 1097-4652
pISSN - 0021-9541
DOI - 10.1002/(sici)1097-4652(199907)180:1<114::aid-jcp13>3.0.co;2-0
Subject(s) - catalase , superoxide dismutase , senescence , biology , nadh dehydrogenase , cytochrome c oxidase , antioxidant , microbiology and biotechnology , glutathione peroxidase , peroxidase , biochemistry , chemistry , enzyme , protein subunit , gene
The activities and mRNA abundances of enzymes that regulate the rate of electron flow through the electron transport chain (ETC), including NADH dehydrogenase, succinate dehydrogenase, and cytochrome c oxidase, were examined in young and senescent fetal lung fibroblasts (WI‐38). We also determined the activities and mRNA abundances of antioxidant defenses including superoxide dismutase, catalase, and glutathione peroxidase. We confirmed our previous report of a senescence‐related increase in the abundance of ND4, a mitochondrially encoded subunit of NADH dehydrogenase. The activities of cytochrome c oxidase and NADH dehydrogenase were also elevated in senescent cultures. No differences were observed in the mRNA abundances of COX‐1, a mitochondrially encoded subunit of cytochrome c oxidase or of nuclearly encoded subunits of various electron transport components (SD, COX‐4, and ND 51). Lucigenin‐detected chemiluminescence and H 2 O 2 generation were both elevated in senescent cells. Catalase activity was also elevated in senescent fibroblasts. However, no differences in catalase mRNA abundance were observed. A small decrease in GSH peroxidase (GPx) mRNA abundance was observed in senescent cells. No other changes in the activities or mRNA abundances of any of the antioxidant defenses were observed in early and late passage cultures. The relationships between oxidant generation, mitochondrial enzyme activities, and antioxidant defense observed during proliferative senescence are dissimilar to those detected between fetal and postnatal fibroblasts as well as those found between fibroblast lines obtained from young and old individuals. The relevance of the differences between these models is discussed. J. Cell. Physiol. 180:114–122, 1999. © 1999 Wiley‐Liss, Inc.