Glucagon-like peptide 2 improves intestinal wound healing through induction of epithelial cell migration in vitro-evidence for a TGF--beta-mediated effect.
OBJECTIVE
In vitro studies suggest that glucagon-like peptide 2 (GLP-2), secreted from enteroendocrine cells in the gastrointestinal tract after food intake, is able to ameliorate mucosal injury in settings of human disease characterized by injury and dysfunction of the intestinal mucosal epithelium. We evaluated this potential of GLP-2 after epithelial trauma by using two in vitro models measuring intestinal epithelial cell proliferation and cell migration.


METHODS
Injuries were induced in confluent monolayers of the small intestinal cells lines IEC-6 and IEC-18, as well as in the colonic cell lines Caco-2 and Colo 320. GLP-2 (50-500 nM) or other peptides were added to the media. Wound healing was investigated after 24 h by quantification of the number of cells migrating across the wound edge. Proliferation of cells was assessed by using photometric mitochondrial incorporation measurement of MTT (3-[4,5-Dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide). Monoclonal TGF-beta antibodies were added to wounded monolayers to examine whether the GLP-2-induced wound healing was TGF-beta-mediated.


RESULTS
Migration assessments revealed a significant stimulation of GLP-2-induced migration in IEC-6 and IEC-18 monolayers compared to the placebo group. No effect was observed in the colon cancer cell lines Caco-2 and Colo 320. Results of the proliferation assays show a significant inhibition of proliferation by GLP-2 in small intestinal cell lines whereas a dose-dependent stimulation of proliferation in colonic epithelial cells was observed. Addition of neutralizing TGF-beta1 antibodies to wounded IEC-6 and IEC-18 monolayers incubated with GLP-2 significantly reduced the number of migrating cells to the level of the placebo group.


CONCLUSIONS
In our in vitro model, it was shown that the GLP-2-induced improvement of intestinal wound healing is TGF-beta-mediated. These effects were predominant in the epithelium of the small intestine compared to colonic epithelium. Our findings provide further insight into mechanisms leading to GLP-2-induced mucosal wound healing. These results suggest that GLP-2 or analogues of this peptide may potentially be useful for the treatment of intestinal disorders characterized by injury and ineffective repair of the intestinal mucosa.
Bulut
K
K
Department of Medicine I, St. Josef Hospital, Ruhr-University Bochum, Gudrunstr. 56, D-44791 Bochum, Germany. kbulut@web.de
Meier
J J
JJ
Ansorge
N
N
Felderbauer
P
P
Schmitz
F
F
Hoffmann
P
P
Schmidt
W E
WE
Gallwitz
B
B
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects; D002460:Cell Line; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000187:drug effects*; D049109:Cell Proliferation / Q000187:drug effects; D004847:Epithelial Cells / Q000166:cytology / Q000187:drug effects*; D005434:Flow Cytometry; D005934:Glucagon / Q000494:pharmacology; D052216:Glucagon-Like Peptide 1; D053767:Glucagon-Like Peptide 2; D004763:Glucagon-Like Peptides; D006801:Humans; D007422:Intestines / Q000166:cytology / Q000187:drug effects* / Q000293:injuries / Q000473:pathology; D010446:Peptide Fragments / Q000494:pharmacology; D010455:Peptides / Q000494:pharmacology*; D011498:Protein Precursors / Q000494:pharmacology; D051381:Rats; D016212:Transforming Growth Factor beta / Q000037:antagonists & inhibitors / Q000276:immunology / Q000494:pharmacology*; D053773:Transforming Growth Factor beta1; D014945:Wound Healing / Q000187:drug effects*
D000911:Antibodies, Monoclonal; D053767:Glucagon-Like Peptide 2; D010446:Peptide Fragments; D010455:Peptides; D011498:Protein Precursors; C508960:TGFB1 protein, human; C508962:Tgfb1 protein, rat; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1; D004763:Glucagon-Like Peptides; D052216:Glucagon-Like Peptide 1; D005934:Glucagon