Figure 13. MT1-MMP activity is required for EC lumen and tube formation and generation of vascular guidance tunnels in 3D collagen matrices.
(A) Representative images from 3D cultures of ECs seeded within collagen type I matrices in the presence or absence of recombinant TIMP-1 or TIMP-3 added at 5 µg/ml. Cultures were fixed, stained and photographed at 24 hr. White arrowheads indicate EC lumenal structures. Bar equals 50 µm. (B) Representative images from 3D cultures of ECs seeded within collagen type I matrices after having undergone treatment with the indicated siRNAs. Cultures were fixed, stained and photographed at 24 hr. White arrowheads indicate EC lumenal structures. Bar equals 50 µm. (C) Representative images of ECs seeded within FITC-labeled collagen type I matrices in the presence or absence of the proteinase inhibitor GM6001 added at 5 µM. Cultures were fixed and photographed using confocal microscopy at 24hrs. White arrowheads indicate vascular guidance tunnels generated as a consequence of the EC lumen and tube formation. Bar equals 100 µm.