ICAM-1 Clustering on Endothelial Cells Recruits VCAM-1

• Main Authors: Jaap D. van Buul, Jos van Rijssel, Floris P. J. van Alphen, Anna-Marieke van Stalborch, Erik P. J. Mul, Peter L. Hordijk
• Format: Article
• Language: English
• Published: Hindawi Limited 2010-01-01
• Series: Journal of Biomedicine and Biotechnology
• Online Access: http://dx.doi.org/10.1155/2010/120328

In the initial stages of transendothelial migration, leukocytes use the endothelial integrin ligands ICAM-1 and VCAM-1 for strong adhesion. Upon adhesion of the leukocyte to endothelial ICAM-1, ICAM-1 is clustered and recruited to the adhered leukocyte, promoting strong adhesion. In this study, we provide evidence for the colocalization of VCAM-1 at sites of ICAM-1 clustering. Anti-ICAM-1 antibody-coated beads were used to selectively cluster and recruit ICAM-1 on primary human endothelial cells. In time, co-localization of ICAM-1 and VCAM-1 around the adherent beads was observed. Biochemical pull-down assays showed that ICAM-1 clustering induced its association to VCAM-1, suggesting a physical link between these two adhesion molecules. The association was partly dependent on lipid rafts as well as on F-actin and promoted adhesion. These data show that VCAM-1 can be recruited, in an integrin-independent fashion, to clustered ICAM-1 which may serve to promote ICAM-1-mediated leukocyte adhesion.