Loading…
Differential regulation of antioxidant enzymes in response to oxidants
We have demonstrated the selective induction of manganese superoxide dismutase (MnSOD) or catalase mRNA after exposure of tracheobronchial epithelial cells in vitro to different oxidant stresses. Addition of H2O2 caused a dose-dependent increase in catalase mRNA in both exponentially growing and con...
Saved in:
Published in: | The Journal of biological chemistry 1991-12, Vol.266 (36), p.24398-24403 |
---|---|
Main Authors: | , , , , , , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
Summary: | We have demonstrated the selective induction of manganese superoxide dismutase (MnSOD) or catalase mRNA after exposure of
tracheobronchial epithelial cells in vitro to different oxidant stresses. Addition of H2O2 caused a dose-dependent increase
in catalase mRNA in both exponentially growing and confluent cells. A 3-fold induction of catalase mRNA was seen at a nontoxic
dose of 250 microM H2O2. Increase in the steady-state mRNA levels of glutathione peroxidase (GPX) and MnSOD were less striking.
Expression of catalase, MnSOD, and GPX mRNA was highest in confluent cells. In contrast, constitutive expression of copper
and zinc SOD (CuZnSOD) mRNA was greatest in dividing cells and was unaffected by H2O2 in both exponentially growing and confluent
cells. MnSOD mRNA was selectively induced in confluent epithelial cells exposed to the reactive oxygen species-generating
system, xanthine/xanthine oxidase, while steady-state levels of GPX, catalase, and CuZnSOD mRNA remained unchanged. The 3-fold
induction of MnSOD mRNA was dose-dependent, reaching a peak at 0.2 unit/ml xanthine oxidase. MnSOD mRNA increases were seen
as early as 2 h and reached maximal induction at 24 h. Immunoreactive MnSOD protein was produced in a corresponding dose-
and time-dependent manner. Induction of MnSOD gene expression was prevented by addition of actinomycin D and cycloheximide.
These data indicate that epithelial cells of the respiratory tract respond to different oxidant insults by selective induction
of certain antioxidant enzymes. Hence, gene expression of antioxidant enzymes does not appear to be coordinately regulated
in these cell types. |
---|---|
ISSN: | 0021-9258 1083-351X |
DOI: | 10.1016/s0021-9258(18)54242-3 |