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FASEB J. 2004 Jun;18(9):977-9. Epub 2004 Apr 1.

Adhesion and signaling by B cell-derived exosomes: the role of integrins.

Author information

1
Section of Clinical Oncology, Department of Medicine, University of Wales College of Medicine, Velindre Hospital, Whitchurch, Cardiff, UK. aled.clayton@velindre-tr.wales.nhs.uk

Abstract

Exosomes are nanometer-sized vesicles secreted by various cells, with potentially diverse roles in physiology. Although emphasis has been placed on their involvement in immune modulation, their potential for more wide-ranging biological effects has not been appreciated. A common exosome feature is the expression of adhesion molecules, which include the integrin family. We have for the first time addressed the possible function of B cell-derived exosome-integrins by examining adhesive interactions of exosomes (immobilized onto beads) with extracellular matrix (ECM) components and cytokine-treated fibroblasts. Integrin (beta1 and beta2) expression was demonstrated by Western blotting and flow cytometry. Binding studies (with blocking antibodies) demonstrated their function in adhesion to collagen-I, fibronectin, and tumor necrosis factor (TNF)-alpha-activated fibroblasts. Exosome adhesion to TNF-alpha-activated fibroblasts also triggered integrin-dependent changes in cytosolic calcium, measured by single cell imaging. Thus, B cell-derived exosomes express functional integrins, which are capable of mediating anchorage to ECM and cell-surface adhesion molecules, and may be a novel mode of delivering adhesion signals at distances beyond that of direct cell-cell contact during inflammation.

PMID:
15059973
DOI:
10.1096/fj.03-1094fje
[Indexed for MEDLINE]

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