Substance P-stimulated interleukin-8 expression in human colonic epithelial cells involves Rho family small GTPases

Biochem J. 2002 Dec 1;368(Pt 2):665-72. doi: 10.1042/BJ20020950.


Interaction of the neuropeptide substance P (SP) and its neurokinin-1 receptor (NK-1R) plays an important role in the pathophysiology of intestinal inflammation. SP is known to stimulate production of interleukin (IL)-6 and IL-8 in the U-373-MG human astrocytoma cell line via activation of p38 MAPK (mitogen-activated protein kinase) and nuclear factor (NF)-kappaB, respectively. However, the signalling mechanisms by which SP-NK-1R interaction induces NF-kappaB activation and IL-8 expression are still not clear. In this study we demonstrate that SP stimulates IL-8 secretion and IL-8 promoter activity in the NCM460 non-transformed human colonic epithelial cell line transfected with NK-1R cDNA. Our results indicate that inhibition of endogenous Rho family proteins (RhoA, Rac1 and Cdc42) by their respective dominant negative mutants significantly decreases SP-induced IL-8 secretion and IL-8 promoter activity. We also demonstrate that SP rapidly activates RhoA, Rac1 and Cdc42 and that co-expression of the dominant negative mutants of RhoA, Rac1 and Cdc42 in NK-1R cDNA-transfected NCM460 cells significantly inhibits SP-induced NF-kappaB-dependent gene expression. These results demonstrate that Rho family small GTPases RhoA, Rac1 and Cdc42 are novel signal transducers for SP-stimulated IL-8 expression.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Cells, Cultured
  • Colon / cytology
  • Colon / drug effects
  • Colon / metabolism*
  • Epithelial Cells / drug effects
  • Epithelial Cells / metabolism
  • Genes, Dominant
  • Humans
  • Interleukin-8 / genetics
  • Interleukin-8 / metabolism*
  • NF-kappa B / drug effects
  • NF-kappa B / genetics
  • NF-kappa B / metabolism
  • Promoter Regions, Genetic
  • Receptors, Neurokinin-1 / drug effects
  • Receptors, Neurokinin-1 / genetics
  • Receptors, Neurokinin-1 / metabolism
  • Serum Response Element / drug effects
  • Signal Transduction
  • Substance P / metabolism
  • Substance P / pharmacology*
  • cdc42 GTP-Binding Protein / drug effects
  • cdc42 GTP-Binding Protein / genetics
  • cdc42 GTP-Binding Protein / metabolism
  • rac1 GTP-Binding Protein / drug effects
  • rac1 GTP-Binding Protein / genetics
  • rac1 GTP-Binding Protein / metabolism
  • rhoA GTP-Binding Protein / drug effects
  • rhoA GTP-Binding Protein / genetics
  • rhoA GTP-Binding Protein / metabolism*


  • Interleukin-8
  • NF-kappa B
  • Receptors, Neurokinin-1
  • Substance P
  • cdc42 GTP-Binding Protein
  • rac1 GTP-Binding Protein
  • rhoA GTP-Binding Protein