HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Sarantos, M. R. Articles by Simon, S. I. Search for Related Content PubMed PubMed Citation Articles by Sarantos, M. R. Articles by Simon, S. I.

Transmigration of Neutrophils across Inflamed Endothelium Is Signaled through LFA-1 and Src Family Kinase¹

Melissa R. Sarantos^*, Hong Zhang, Ulrich Y. Schaff^*, Neha Dixit^*, Heather N. Hayenga^*, Clifford A. Lowell and Scott I. Simon^2,*

^* Department of Biomedical Engineering, University of California, Davis, CA 95616; and Department of Laboratory Medicine, University of California, San Francisco, CA 94143

Leukocyte capture on inflamed endothelium is facilitated by a shift in LFA-1 from low to high affinity that supports binding to ICAM-1. LFA-1 bonds help anchor polymorphonuclear leukocytes (PMN) to inflamed endothelium in shear flow, and their redistribution to the leading edge guides pseudopod formation, migration, and extravasation. These events can be disrupted at the plasma membrane by stabilizing LFA-1 in a low- or intermediate-affinity state with allosteric small molecules. We hypothesized that a minimum dimeric bond formation between high-affinity LFA-1 and ICAM-1 under shear stress is necessary to catalyze transmembrane signaling of directed cell migration. Microspheres and substrates were derivatized with monomeric or dimeric ICAM-1 to simulate the surface of inflamed endothelium under defined ligand valence. Binding to dimeric ICAM-1, and not monomeric ICAM-1, was sufficient to elicit assembly of F-actin and phosphorylation of Src family kinases that colocalized with LFA-1 on adherent PMN. Genetic deletion or small molecule inhibition of Src family kinases disrupted their association with LFA-1 that correlated with diminished polarization of arrested PMN and abrogation of transmigration on inflamed endothelium. We conclude that dimeric bond clusters of LFA-1/ICAM-1 provide a key outside-in signal for orienting cytoskeletal dynamics that direct PMN extravasation at sites of inflammation.

The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked advertisement in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

¹ This work was supported by National Institutes of Health (NIH) Grants AI47294 (to S.I.S.), AI65495, and AI68150 (to C.L.) and an NIH training grant to U.Y.S. (AI060555).

² Address correspondence and reprint requests to Dr. Scott I. Simon, Department of Biomedical Engineering, 451 East Health Sciences Drive, Davis, CA 95616. E-mail address: sisimon{at}ucdavis.edu

³ Abbreviations used in this paper: PMN, polymorphonuclear leukocytes; bEND, brain endothelial; GPCR, G protein-coupled receptor; HSA, human serum albumin; MFI, mean fluorescence intensity; SFK, Src family kinase; TEM, transendothelial migration.