Substance P induces intestinal wound healing via fibroblasts--evidence for a TGF-beta-dependent effect.
BACKGROUND
Substance P (SP) and calcitonin gene-related peptide (CGRP) are neurotransmitters of the afferent sensory nervous system. In experimental models of colitis in rats and rabbits, a protective role of SP and CGRP on the intestinal mucosa was presumed. In part, mucosal protection depends on a SP-mediated and CGRP-mediated modulation of mucosal blood flow after injury. We thought to explore whether there is a fibroblast-mediated effect of SP and CGRP on epithelial cell restitution in vitro.


METHODS
Rat kidney fibroblast (NRK-49F) cell lines were exposed to CGRP or SP in various concentrations. After incubation, the cell culture supernatants were taken from the fibroblast cultures and were directly applied to IEC-18 or Caco-2 monolayers, which had been wounded with a razor blade 24 h before the experiments. Epithelial cell migration was assessed by counting cells across the wound edge. Epithelial cell proliferation was assessed using the 3-[4, 5-dimethylthiazol-2-yl]-2, 5-diphenyl-tetrazolium bromide (MTT) test.


RESULTS
SP significantly induced epithelial cell migration and inhibited epithelial cell proliferation via stimulation of fibroblasts when supernatants were directly applied to epithelial cells in vitro. The effects on epithelial cell migration were abolished after neutralising anti-transforming growth factor-beta (TGF-beta) was added to the cell cultures. CGRP had no effect on epithelial cells via stimulation of fibroblasts. Neither CGRP nor SP had any effect on epithelial cell migration or proliferation when directly applied to epithelial cells.


CONCLUSIONS
SP modulates epithelial cell restitution in vitro mediated by fibroblasts. The epithelial cell migration depends on a TGF-beta release from SP-stimulated fibroblasts. This observation underlines an important role for the sensory nervous system in mucosal defence and repair and in keeping mucosal homeostasis. Modulation of SP may be potentially useful for the treatment of various intestinal disorders characterised by injury and ineffective repair of the intestinal mucosa.
Felderbauer
Peter
P
Department of Internal Medicine I, St. Josef-Hospital, Ruhr-University of Bochum, Gudrun Str. 54, 44791, Bochum, Germany. peter.felderbauer@rub.de
Bulut
Kerem
K
Hoeck
Karoline
K
Deters
Susanne
S
Schmidt
Wolfgang E
WE
Hoffmann
Peter
P
D000818:Animals; D018938:Caco-2 Cells; D015740:Calcitonin Gene-Related Peptide / Q000378:metabolism* / Q000494:pharmacology; D002465:Cell Movement; D049109:Cell Proliferation; D017077:Culture Media, Conditioned / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004847:Epithelial Cells / Q000378:metabolism* / Q000473:pathology; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D007413:Intestinal Mucosa / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology; D008070:Lipopolysaccharides / Q000494:pharmacology; D019899:Paracrine Communication / Q000187:drug effects; D051381:Rats; D013373:Substance P / Q000378:metabolism* / Q000494:pharmacology; D013997:Time Factors; D053773:Transforming Growth Factor beta1 / Q000378:metabolism*; D014945:Wound Healing / Q000187:drug effects
D017077:Culture Media, Conditioned; D008070:Lipopolysaccharides; D053773:Transforming Growth Factor beta1; D013373:Substance P; D015740:Calcitonin Gene-Related Peptide