title: ICAM-1 regulates neutrophil adhesion and transcellular migration of TNF-alpha-activated vascular endothelium under flow.
abstract: In vivo, leukocyte transendothelial migration (TEM) occurs at endothelial cell junctions (paracellular) and nonjunctional (transcellular) locations, whereas in vitro models report that TEM is mostly paracellular. The mechanisms that control the route of leukocyte TEM remain unknown. Here we tested the hypothesis that elevated intercellular adhesion molecule-1 (ICAM-1) expression regulates the location of polymorphonuclear leukocyte (PMN) TEM. We used an in vitro flow model of tumor necrosis factor-alpha (TNF-alpha)-activated human umbilical vein endothelium cells (HUVECs) or an HUVEC cell line transfected with ICAM-1GFP (green fluorescent protein) and live-cell fluorescence microscopy to quantify the location of PMN adhesion and TEM. We observed robust transcellular TEM with TNF-alpha-activated HUVECs and ICAM-1GFP immortalized HUVECS (iHUVECs). In contrast, primary CD3+ T lymphocytes exclusively used a paracellular route. Endothelial ICAM-1 was identified as essential for both paracellular and transcellular PMN transmigration, and interfering with ICAM-1 cytoplasmic tail function preferentially reduced transcellular TEM. We also found that ICAM-1 surface density and distribution as well as endothelial cell shape contributed to transcellular TEM. In summary, ICAM-1 promotes junctional and nonjunctional TEM across inflamed vascular endothelium via distinct cytoplasmic tail associations.
authors.affiliation: Center for Excellence in Vascular Biology, Department of Pathology, Brigham and Women's Hospital and Harvard Medical School, 77 Avenue Louis Pasteur, NRB 752P, Boston, MA 02215, USA.
authors.forename: Lin
authors.initials: L
authors.lastname: Yang
authors.forename: Richard M
authors.initials: RM
authors.lastname: Froio
authors.forename: Tracey E
authors.initials: TE
authors.lastname: Sciuto
authors.forename: Ann M
authors.initials: AM
authors.lastname: Dvorak
authors.forename: Ronen
authors.initials: R
authors.lastname: Alon
authors.forename: Francis W
authors.initials: FW
authors.lastname: Luscinskas
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D002448:Cell Adhesion / Q000502:physiology; D002465:Cell Movement / Q000502:physiology; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects / Q000502:physiology; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D066298:In Vitro Techniques; D018799:Intercellular Adhesion Molecule-1 / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D009504:Neutrophils / Q000166:cytology / Q000502:physiology*; D010446:Peptide Fragments / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000494:pharmacology; D013601:T-Lymphocytes / Q000502:physiology; D014162:Transfection; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
chemical_list: D010446:Peptide Fragments; D011993:Recombinant Fusion Proteins; D011994:Recombinant Proteins; D014409:Tumor Necrosis Factor-alpha; D018799:Intercellular Adhesion Molecule-1; D049452:Green Fluorescent Proteins