Migration of human granulocytes through reconstituted basement membrane isnot dependent on matrix metalloproteinase-9 (MMP-9)

Transmigration of human granulocytes across a basal lamina equivalent was s tudied in vitro. Transwell(R) inserts were coated with Matrigel(R), a recon stituted basement membrane. Granulocytes (2 x 10(6)) were applied to the up per chamber. As chemoattractant interleukin-8 (IL-8; 25 ng/ml) was added to the lower chamber. After 1 h of migration, cells were counted in the lower chamber. Specific hydroxamate inhibitors of MMPs (BB-3103, Ro 31-9790) or of serine proteases (Pefabloc(R), leupeptin) were added at various concentr ations to both chambers before the start of migration. Additional experimen ts were performed with alpha (2)-macroglobulin, a natural inhibitor of MMPs and a monoclonal antibody which specifically blocks the activity of MMP-9. Migration of granulocytes through Matrigel could not be reduced significan tly by any of the MMP inhibitors. A dose-dependent impairment of transmigra tion was only found with Pefabloc, however, this substance also induced sev ere morphological changes of the cells. The other inhibitor of serine prote ases, leupeptin, did not influence migration at all. (C) 2001 Elsevier Scie nce B.V. All rights reserved.