Movie 1

BMDM and Hoxb8 macrophages migrating through fibrillary collagen. BMDMs or Hoxb8 macrophages were seeded in the upper chamber of transwell chambers filled with fibrillar collagen I. Z-series of images were acquired 1h after seeding at the surface of the matrices, at the surface and at 300 μm below the surface of the collagen gel. Time-lapse imaging was acquired every 10 min during 20 h using the 10~ objective of an inverted microscope. Left panels show macrophages at the surface (z=0μm) of the gel over time. Right panels show macrophages in the thickness of the matrix (z=-300μm). Note that cells are progressively disappearing from the upper layer of the gel and concomitantly appearing inside the matrix.