title: Endothelial paxillin and focal adhesion kinase (FAK) play a critical role in neutrophil transmigration.
abstract: During an inflammatory response, endothelial cells undergo morphological changes to allow for the passage of neutrophils from the blood vessel to the site of injury or infection. Although endothelial cell junctions and the cytoskeleton undergo reorganization during inflammation, little is known about another class of cellular structures, the focal adhesions. In this study, we examined several focal adhesion proteins during an inflammatory response. We found that there was selective loss of paxillin and focal adhesion kinase (FAK) from focal adhesions in proximity to transmigrating neutrophils; in contrast the levels of the focal adhesion proteins β1-integrin and vinculin were unaffected. Paxillin was lost from focal adhesions during neutrophil transmigration both under static and flow conditions. Down-regulating endothelial paxillin with siRNA blocked neutrophil transmigration while having no effect on rolling or adhesion. As paxillin dynamics are regulated partly by FAK, the role of FAK in neutrophil transmigration was examined using two complementary methods. siRNA was used to down-regulate total FAK protein while dominant-negative, kinase-deficient FAK was expressed to block FAK signaling. Disruption of the FAK protein or FAK signaling decreased neutrophil transmigration. Collectively, these findings reveal a novel role for endothelial focal adhesion proteins paxillin and FAK in regulating neutrophil transmigration.
authors.affiliation: Department of Physiology and Pharmacology, University of Calgary, Calgary, AB, Canada.
authors.forename: Sean A
authors.initials: SA
authors.lastname: Parsons
authors.forename: Ritu
authors.initials: R
authors.lastname: Sharma
authors.forename: Dawn L
authors.initials: DL
authors.lastname: Roccamatisi
authors.forename: Hong
authors.initials: H
authors.lastname: Zhang
authors.forename: Björn
authors.initials: B
authors.lastname: Petri
authors.forename: Paul
authors.initials: P
authors.lastname: Kubes
authors.forename: Pina
authors.initials: P
authors.lastname: Colarusso
authors.forename: Kamala D
authors.initials: KD
authors.lastname: Patel
mesh_terms: D002448:Cell Adhesion / Q000235:genetics; D002478:Cells, Cultured; D015536:Down-Regulation / Q000235:genetics / Q000276:immunology; D004727:Endothelium / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D051416:Focal Adhesion Protein-Tyrosine Kinases / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D022001:Focal Adhesions / Q000473:pathology; D006801:Humans; D007249:Inflammation; D036904:Leukocyte Rolling / Q000235:genetics; D009154:Mutation / Q000235:genetics; D009504:Neutrophils / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D051419:Paxillin / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000235:genetics; D057705:Transendothelial and Transepithelial Migration / Q000235:genetics / Q000276:immunology*; D019076:Transgenes / Q000235:genetics
chemical_list: D051419:Paxillin; D034741:RNA, Small Interfering; D051416:Focal Adhesion Protein-Tyrosine Kinases