Glutathione s-transferases in tracheobronchial epithelium:
differential expression and regulation by vitamin a and collagen
substratum.
Reddy, P. M. Sekhar, Chen-Pei D. Tu, and Reen Wu.
California Regional Primate Research Center, and Department of
Internal Medicine, Division of Pulmonary and Critical Care Medicine,
University of California, Davis, CA 95616, Department of Biochemistry
and Molecular Biology, The Pennsylvania State University, University
Park, PA 16802
APStracts 2:0082L, 1995.
The purpose of this study is to characterize GST gene expression in
airway epithelium both in vivo and in vitro. Immunohistochemical
staining of non-human primate lungs of well-controlled healthy
animals reveals the presence of [alpha]- and p-class GST isoenzymes
in ciliated bronchial epithelium. The stain of [mu]-GST antibody is
either very low or absent in some of these monkey lungs. We observed
that primary tracheobronchial epithelial (TBE) cells isolated from
human and monkey pulmonary tissues maintain a relatively high level
of GST enzymatic activity in culture, as compared with various
immortalized human TBE cell lines and other non-pulmonary cell lines.
Northern blot analysis demonstrated the presence of [mu]-, p-, and
microsomal-GST messages, but not the [alpha]-class message in
cultures of primary TBE cells as well as in various human TBE cell
lines. The expression of [mu]- and p-class GST genes can be further
regulated in culture by various environmental factors., however, most
of these regulating factors are associated with TBE cell
differentiation in culture. For instance, vitamin A treatment, which
was shown to enhance mucous cell differentiation in vitro, stimulated
the message levels of [mu]- and p-class GST. Furthermore, plating
cells on collagen gel substrata, which also enhanced mucous cell
differentiation in culture, instead of plastic culture surface
enhanced total GST enzymatic activity by eightfold, and this
enhancement is related to an increase in the expression of the p
-class GST gene. These results demonstrated that GST genes are
differentially expressed and regulated by various environmental
factors in primary TBE cells and various cell lines, and the
regulation is correlated to the mucous cell differentiation in
culture.
Received 23 September 1994; accepted in final form 10 May 1995.
APS Manuscript Number L282-4.
Article publication pending Am. J. Physiol. (Lung Cell. Mol.
Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 26 May 1995.