Neurotensin stimulates IL-8 expression in human colonic epithelial cells through
Rho GTPase-mediated NF-?B pathways.
Zhao, Dezheng, Sabina Kuhnt-Moore, Huiyan Zeng, Jack S. Wu, Mary P. Moyer, and
Charalabos Pothoulakis.
1Division of Gastroenterology, 2Department of Pathology, Beth Israel Deaconess
Medical Center, Harvard Medical School, Boston, Massachusetts 02468; and 3INCELL
Corporation, San Antonio, Texas 78249
APStracts 10:0064C, 2003.
Neurotensin (NT), a neuropeptide highly expressed in the gastrointestinal tract,
participates in the pathophysiology of intestinal inflammation. We recently showed that
NT stimulates interleukin-8 (IL-8) expression in NCM460 nontransformed human
colonic epithelial cells via both MAPK- and NF-?B-dependent pathways. However, the
molecular mechanism by which NT induces expression of proinflammatory cytokines
such as IL-8 has not been investigated. In this study we show that inhibition of
endogenous Rho family proteins (RhoA, Rac1, and Cdc42) by their respective dominant
negative mutants inhibits NT-induced IL-8 protein production and promoter activity.
Western blot experiments demonstrated that NT strongly activated RhoA, Rac1, and
Cdc42. Overexpression of the dominant negative mutants of RhoA, Rac1, and Cdc42
significantly inhibited NT-induced NF-?B-dependent reporter gene expression and NF-
?B DNA binding activity. NT also stimulated p38 MAPK phosphorylation, and
overexpression of dominant negative mutants of RhoA, Rac1, and Cdc42 did not
significantly alter p38 and ERK1/2 phosphorylation in response to NT. Together, our
findings indicate that NT-stimulated IL-8 expression is mediated via a Rho-dependent
NF-?B-mediated pathway.
Received 12 July 2002; accepted in final form 22 January 2003
APS Manuscript Number C328-2.
Article publication pending Am J Physiol Cell Physiol
ISSN 1080-4757 Copyright 2003 The American Physiological Society.
Published in APStracts on 25 March 2003