Induction of LFA-1-dependent neutrophil rolling on ICAM-1 by engagement of E-selectin.
OBJECTIVE
To study rolling of mouse neutrophils on E-selectin and ICAM-1 in an ex vivo flow chamber system.


METHODS
The authors developed a small autoperfused flow chamber (20 x 200-microm cross section) that allows direct visualization of cells with and without fluorescent labeling and does not require recirculation of blood.


RESULTS
Neutrophils rolled on E-selectin alone, but were unable to interact with immobilized ICAM-1. When ICAM-1 was co-immobilized with E-selectin, the number of cells that rolled was doubled, but no significant firm adhesion was observed. This phenomenon was specific for E-selectin, and no enhancement of rolling was observed when P-selectin was immobilized with ICAM-1. The increased neutrophil rolling seen on E-selectin and ICAM-1 substrates required beta2 integrins. Treating mice with antibodies to the beta2 integrins LFA-1 and Mac-1 showed that LFA-1 was primarily responsible for mediating rolling on ICAM-1 in this model. Increased rolling on E-selectin and ICAM-1 was significantly reduced following administration of a specific p38 mitogen-activated protein kinase (MAPK) inhibitor.


CONCLUSIONS
The data show that neutrophil rolling on E-selectin leads to partial activation of LFA-1, enabling LFA-1-dependent rolling on ICAM-1. This mechanism is likely to amplify and accelerate neutrophil recruitment in inflammation.
Chesnutt
Betsy C
BC
Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia, USA.
Smith
David F
DF
Raffler
Nikolai A
NA
Smith
Michael L
ML
White
E J
EJ
Ley
Klaus
K
D000818:Animals; D002478:Cells, Cultured; D019040:E-Selectin / Q000378:metabolism*; D007249:Inflammation / Q000378:metabolism; D018799:Intercellular Adhesion Molecule-1 / Q000378:metabolism*; D036904:Leukocyte Rolling / Q000502:physiology*; D016169:Lymphocyte Function-Associated Antigen-1 / Q000378:metabolism*; D051379:Mice; D008822:Mice, Transgenic; D009504:Neutrophils / Q000166:cytology / Q000502:physiology*
D019040:E-Selectin; D016169:Lymphocyte Function-Associated Antigen-1; D018799:Intercellular Adhesion Molecule-1