title: Characterization of eosinophil adhesion to TNF-alpha-activated endothelium under flow conditions: alpha 4 integrins mediate initial attachment, and E-selectin mediates rolling.
abstract: The multistep model of leukocyte adhesion reveals that selectins mediate rolling interactions and that integrins mediate firm adhesion processes. In this study, the interaction between eosinophils and TNF-alpha-activated HUVEC (second or third passage) was studied under flow conditions (0.8 and 3.2 dynes/cm2). Especially the role of alpha 4 integrins on eosinophils and E-selectin on HUVEC was studied. Inhibition of the integrin alpha 4 chain on eosinophils reduced the number of firmly adhered resting eosinophils to TNF-alpha-stimulated endothelium by 43% whereas the percentage rolling cells increased 2.2-fold compared with untreated control eosinophils. Blocking of E-selectin on the endothelium reduced the number of adherent eosinophils by only 23% and 16%. In this situation, however, hardly any rolling adhesion was observed, and the few rolling cells showed a low rolling velocity. Blocking both alpha 4 integrin on eosinophils and E-selectin on HUVEC reduced the number of adhered eosinophils by 95%. P-selectin did not significantly participate in eosinophil adhesion to TNF-alpha-activated HUVEC. Inhibition of both alpha 4 integrins and beta 2 integrins on eosinophils resulted in a reduction of adhered cells by 65% and a 3-fold increase in percentage rolling cells. Taken together, these results clearly show that resting eosinophils preferentially use constitutively active alpha 4 integrins (alpha 4 beta 1, alpha 4 beta 7) for the first attachment to TNF-alpha-activated HUVEC. In addition, alpha 4 integrins and E-selectin work synergistically in eosinophil adherence to TNF-alpha-activated HUVEC. Although E-selectin is important for eosinophil rolling under these conditions, P-selectin plays only a minor role.
authors.affiliation: Department of Pulmonary Diseases and Haematology, Academisch Ziekenhuis Utrecht, The Netherlands.
authors.forename: L H
authors.initials: LH
authors.lastname: Ulfman
authors.forename: P H
authors.initials: PH
authors.lastname: Kuijper
authors.forename: J A
authors.initials: JA
authors.lastname: van der Linden
authors.forename: J W
authors.initials: JW
authors.lastname: Lammers
authors.forename: J J
authors.initials: JJ
authors.lastname: Zwaginga
authors.forename: L
authors.initials: L
authors.lastname: Koenderman
mesh_terms: D015703:Antigens, CD / Q000097:blood / Q000502:physiology*; D001783:Blood Flow Velocity; D018821:CD18 Antigens / Q000097:blood / Q000502:physiology; D002448:Cell Adhesion / Q000502:physiology; D015815:Cell Adhesion Molecules / Q000097:blood / Q000502:physiology*; D002465:Cell Movement / Q000502:physiology*; D002478:Cells, Cultured; D019040:E-Selectin / Q000502:physiology*; D004730:Endothelium, Vascular / Q000166:cytology / Q000502:physiology*; D004804:Eosinophils / Q000502:physiology*; D018056:Hemorheology; D006801:Humans; D039441:Integrin alpha4; D010477:Perfusion; D013314:Stress, Mechanical; D014409:Tumor Necrosis Factor-alpha / Q000502:physiology*
chemical_list: D015703:Antigens, CD; D018821:CD18 Antigens; D015815:Cell Adhesion Molecules; D019040:E-Selectin; D014409:Tumor Necrosis Factor-alpha; D039441:Integrin alpha4