Migration of Eosinophils through Basement Membrane Components in Vitro: Role of Matrix Metalloproteinase-9

In general, inflammatory cells cross basement membranes by producing proteinases. To investigate the role of proteinases in eosinophil basement membrane migration, we studied peripheral blood eosinophils in Matrigel®-coated chemotaxis chambers. Electron microscopy showed degradation of the Matrigel® layer when eosinophils, added to the upper chamber, transmigrated the membrane in the presence of both platelet-activating factor (PAF) in the lower chamber and interleukin (IL)-5 in both chambers. In the absence of either or both PAF and IL-5, no changes occurred in the Matrigel® layer. Matrigel® transmigration of eosinophils induced by PAF and IL-5 was inhibited by 1,10-phenanthroline, batimastat, 3,4-dichloroisocoumarin, chymostatin, and a neutralizing antibody for the matrix metalloproteinase (MMP)-9, indicating that serine proteinase(s) and MMP, specifically MMP-9, were involved in the transmigration of eosinophils through Matrigel®. In contrast, eosinophil migration through a bare membrane was not affect...