Pathological angiogenesis contributes to cancer progression and chronic inflammatory diseases. In inflammatory bowel disease, the microvasculature expands by intussusceptive angiogenesis (IA), a poorly characterized mechanism involving increased blood flow and splitting of pre-existing capillaries. In this report, mice lacking the protease MT1-MMP in endothelial cells (MT1 iDEC ) presented limited IA in the capillary plexus of the colon mucosa assessed by 3D imaging during 1% DSS-induced colitis. This resulted in better tissue perfusion, preserved intestinal morphology, and milder disease activity index. Combined in vivo intravital microscopy and lentiviral rescue experiments with in vitro cell culture demonstrated that MT1-MMP activity in endothelial cells is required for vasodilation and IA, as well as for nitric oxide production via binding of the Cterminal fragment of MT1-MMP substrate thrombospondin-1 (TSP1) to CD47/avb3 integrin. Moreover, TSP1 levels were significantly higher in serum from IBD patients and in vivo administration of an anti-MT1-MMP inhibitory antibody or a nonamer peptide spanning the avb3 integrin binding site in TSP1 reduced IA during mouse colitis. Our results identify MT1-MMP as a new actor in inflammatory IA and a promising therapeutic target for inflammatory bowel disease.

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We did not find RasI polymorphisms associated with atopic disease. The genetic findings in atopy and asthma may be very different according to ethnic and local characteristics, and they must be carefully verified in different population samples.