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Migration through basement membrane modulates eosinophil expression of CD44
M-J Dallaire1, C Ferland, S Lavigne
1Unité de Recherche en Pneumologie, Centre de Recherche de Hôpital Laval, Institut Universitaire de Cardiologie et de Pneumologie de l'Université Laval, Sainte-Foy, Québec, Canada.
Background:
Tissue eosinophils express more membrane receptors and release more mediators than blood eosinophils, suggesting that migration from blood to tissue modulates eosinophil phenotype and functions.
Objective:
We postulated that eosinophil passage through endothelial basement membrane, an important step of eosinophil migration into tissue, may be responsible for some of these changes.
Method:
We previously showed that 5-oxo-6, 8, 11, 14-eicosatetraenoic acid (5-oxo-ETE) in combination with IL-5 promotes eosinophil migration through Matrigel, a mouse tumour cell-derived basement membrane. Using this model, we evaluated the effect of trans-Matrigel migration on purified human blood eosinophil expressions of CD44, CD69 and HLA-DR that either increase or appear on activated eosinophils, and releases of peroxidase (EPO), leukotriene (LT) C(4) and granulocyte-monocyte colony stimulating factor (GM-CSF).
Results:
IL-5, but not 5-oxo-ETE, increased eosinophil expression of CD44 and CD69. Migration of eosinophils through Matrigel significantly increased CD44 expression level over the one induced by IL-5 (P = 0.0001). Migration through Matrigel did not modify CD69 expression compared with the one obtained in the presence of IL-5 alone; however, incubation of eosinophils on Matrigel decreased IL-5-induced CD69 (P = 0.0001). Trans-Matrigel migration did not modify HLA-DR expression, nor EPO, LTC(4) and GM-CSF releases.
Conclusion:
These data show that in vitro trans-Matrigel migration and Matrigel contact modulate eosinophil membrane receptor expression. Consequently, they suggest that migration through basement membrane mediates changes in cell-surface phenotype observed on activated eosinophils and probably prepares them for interactions with tissue components and cells.