CD47 regulates collagen I-induced cyclooxygenase-2 expression and intestinal epithelial cell migration.
Increased epithelial cell expression of the cyclooxygenase-2 (COX-2) enzyme is a characteristic event of both inflammatory bowel disease and colon cancer. We here report the novel findings that collagen I-induced de novo synthesis of COX-2 in intestinal epithelial cells is inhibited by pertussis toxin (PTX) and by an inhibitory peptide selective for the heterotrimeric G alpha(i3)-protein. These findings could be explained by a regulatory involvement of the G-protein-dependent integrin-associated protein CD47. In support of this notion, we observed a collagen I-induced association between CD47 and alpha2 integrins. This association was reduced by a blocking anti-CD47 antibody but not by PTX or a control anti-beta2 antibody. Furthermore, a blocking antibody against CD47, dominant negative CD47 or specific siRNA knock down of CD47, significantly reduced collagen I-induced COX-2 expression. COX-2 has previously been shown to regulate intestinal epithelial cell adhesion and migration. Morphological analysis of intestinal cells adhering to collagen I revealed a co-localisation of CD47 and alpha2 integrins to non-apoptotic membrane blebs enriched in Rho A and F-actin. The blocking CD47 antibody, PTX and a selective COX-2 inhibitor, dramatically inhibited the formation of these blebs. In accordance, migration of these cells on a collagen I-coated surface or through a collagen I gel were significantly reduced by the CD47 blocking antibody, siRNA knock down of CD47 and the COX-2 inhibitor NS-398. In conclusion, we present novel data that identifies the G-protein-dependent CD47 protein as a key regulator of collagen I-induced COX-2 expression and a promoter of intestinal epithelial cell migration.
Broom
Oliver Jay
OJ
Cell and Experimental Pathology, Department of Laboratory Medicine, Lund University, Clinical Research Centre, Malmö University Hospital (UMAS), Malmö, Sweden.
Zhang
Yuan
Y
Oldenborg
Per-Arne
PA
Massoumi
Ramin
R
Sjölander
Anita
A
D015153:Blotting, Western; D051928:CD47 Antigen / Q000276:immunology*; D002465:Cell Movement / Q000276:immunology*; D002478:Cells, Cultured; D024042:Collagen Type I / Q000502:physiology*; D051546:Cyclooxygenase 2 / Q000096:biosynthesis*; D004790:Enzyme Induction; D006801:Humans; D047468:Immunoprecipitation; D007413:Intestinal Mucosa / Q000166:cytology*
D051928:CD47 Antigen; D024042:Collagen Type I; D051546:Cyclooxygenase 2