Regulation of superoxide dismutase in primary cultures of rat
colonic smooth muscle cells.
Tannahill, C. L., S. A. Stevenot, E. Y. Eaker, J. E. Sallustio, H. S.
Nick, and J. F. Valentine.
Department of Medicine and Department of Biochemistry and Molecular
Biology, University of Florida College of Medicine and the
Gainesville VA Medical Center, Gainesville, FL 32610
APStracts 3:0274G, 1996.
We have observed a rapid induction of manganese superoxide dismutase
(MnSOD) in epithelial, neuronal and smooth muscle cells (SMC)
following acetic acid induced colitis. To examine the regulation of
MnSOD in the SMC more specifically, primary cultures of colonic SMC
were developed by enzymatic digestion of the circular muscle layer
from an adult rat. SMC were treated for 2-72h with 0.5[mu]g/ml E.
coli endotoxin (LPS), 10 ng/ml tumor necrosis factor-[alpha]
(TNF[alpha]) or 2 ng/ml interleukin-1[beta] (IL-1[beta]). Co
-treatments were performed with IL-1[beta] and 4[mu]M actinomycin or
50[mu]M cycloheximide. Northern analysis demonstrated a 23-fold, 8
-fold and 6-fold inductions of MnSOD mRNA by IL-1[beta], LPS or
TNF[alpha] respectively. The induction of MnSOD by IL-1[beta] was
eliminated by actinomycin but not by cycloheximide implicating a
requirement for denovo transcription. Western analysis resulted in a
23.7-fold induction of MnSOD protein after 48h treatment with IL
-1[beta]. The induction of MnSOD by IL-1[beta] and other inflammatory
mediators may serve as a protective mechanism to reduce oxygen free
radical and nitric oxide mediated cell damage during inflammation.
Received 21 June 1996; accepted in final form 12 December 1996.
APS Manuscript Number G249-6.
Article publication pending Am. J. Physiol. (Gastrointest. Liver
Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 31 December 1996