Delay of migrating leukocytes by the basement membrane deposited by endothelial cells in long-term culture.

ABSTRACT: We investigated the migration of human leukocytes through endothelial cells (EC), and particularly their underlying basement membrane (BM). EC were cultured for 20days on 3?m-pore filters or collagen gels to form a distinct BM, and then treated with tumour necrosis factor-?, interleukin-1? or interferon-?. Neutrophil migration through the cytokine-treated EC and BM was delayed for 20-day compared to 4-day cultures. The BM alone obstructed chemotaxis of neutrophils, and if fresh EC were briefly cultured on stripped BM, there was again a hold-up in migration. In studies with lymphocytes and monocytes, we could detect little hold-up of migration for 20-day versus 4-day cultures, in either the filter- or gel-based models. Direct microscopic observations showed that BM also held-up neutrophil migration under conditions of flow. Treatment of upper and/or lower compartments of filters with antibodies against integrins, showed that neutrophil migration through the endothelial monolayer was dependent on ?(2)-integrins, but not ?1- or ?(3)-integrins. Migration from the subendothelial compartment was supported by ?1- and ?(2)-integrins for all cultures, but blockade of ?(3)-integrin only inhibited migration effectively for 20-day cultures. Flow cytometry indicated that there was no net increase in expression of ?1- or ?3-integrins during neutrophil migration, and that their specific subendothelial function was likely dependent on turnover of integrins during migration. These studies show that BM is a distinct barrier to migration of human neutrophils, and that ?(3)-integrins are particularly important in crossing this barrier. The lesser effect of BM on lymphocytes and monocytes supports the concept that crossing the BM is a separate, leukocyte-specific, regulated step in migration.

SUBMITTER: Burton VJ 

PROVIDER: S-EPMC3025349 | biostudies-literature | 2011 Feb

REPOSITORIES: biostudies-literature