Early divergent lung antioxidant enzyme expression in response to
lipopolysaccharide.
Clerch, Linda Biadasz, Angelique Wright, David J. Chung, and Donald
Massaro.
Lung Biology Laboratory, Georgetown University School of Medicine,
Department of Pediatrics and Medicine, Washington, DC 20007
APStracts 3:0123L, 1996.
Lipopolysaccharide (LPS), a component of the cell wall of Gram
-negative bacteria, interacts with eukaryotic cells causing changes in
gene expression and a rapid increase in the formation of superoxide
and hydrogen peroxide (H2O2). We now report that, within 6 hours of
treating rats with LPS, there was a divergent response in the lung of
manganese superoxide dismutase (MnSOD) and catalase expression
without a change in expression of copper-zinc superoxide dismutase or
glutathione peroxidase. The activity and mRNA concentration of MnSOD
increased during the time catalase mRNA concentration and activity
decreased. These divergent changes and activation of nuclear factor
_B (NF-_B) were preceded by a fall, one hour after LPS-treatment, in
the RNA-binding activity of two redox-sensitive proteins: MnSOD RNA
-binding protein and catalase RNA-binding protein. The rapid onset of
these changes, the bacteriostatic properties of H2O2, and the
signaling function of NF-_B suggest the divergent expression of MnSOD
and catalase is a coordinated component of the acute phase reaction
to bacterial invasion.
Received 13 March 1996; accepted in final form 11 July 1996.
APS Manuscript Number L80-6.
Article publication pending Am. J. Physiol. (Lung Cell. Mol.
Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 4 August 1996