title: The RhoA guanine nucleotide exchange factor, LARG, mediates ICAM-1-dependent mechanotransduction in endothelial cells to stimulate transendothelial migration.
abstract: RhoA-mediated cytoskeletal rearrangements in endothelial cells (ECs) play an active role in leukocyte transendothelial cell migration (TEM), a normal physiological process in which leukocytes cross the endothelium to enter the underlying tissue. Although much has been learned about RhoA signaling pathways downstream from ICAM-1 in ECs, little is known about the consequences of the tractional forces that leukocytes generate on ECs as they migrate over the surface before TEM. We have found that after applying mechanical forces to ICAM-1 clusters, there is an increase in cellular stiffening and enhanced RhoA signaling compared with ICAM-1 clustering alone. We have identified that leukemia-associated Rho guanine nucleotide exchange factor (LARG), also known as Rho GEF 12 (ARHGEF12) acts downstream of clustered ICAM-1 to increase RhoA activity, and that this pathway is further enhanced by mechanical force on ICAM-1. Depletion of LARG decreases leukocyte crawling and inhibits TEM. To our knowledge, this is the first report of endothelial LARG regulating leukocyte behavior and EC stiffening in response to tractional forces generated by leukocytes.
authors.affiliation: Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599;
authors.forename: Elizabeth C
authors.initials: EC
authors.lastname: Lessey-Morillon
authors.forename: Lukas D
authors.initials: LD
authors.lastname: Osborne
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Monaghan-Benson
authors.forename: Christophe
authors.initials: C
authors.lastname: Guilluy
authors.forename: E Timothy
authors.initials: ET
authors.lastname: O'Brien
authors.forename: Richard
authors.initials: R
authors.lastname: Superfine
authors.forename: Keith
authors.initials: K
authors.lastname: Burridge
mesh_terms: D015153:Blotting, Western; D002478:Cells, Cultured; D015638:Cytochalasin D / Q000494:pharmacology; D003599:Cytoskeleton / Q000187:drug effects / Q000276:immunology / Q000378:metabolism; D042783:Endothelial Cells / Q000276:immunology* / Q000378:metabolism; D061307:Human Umbilical Vein Endothelial Cells / Q000276:immunology / Q000378:metabolism; D006801:Humans; D007231:Infant, Newborn; D018799:Intercellular Adhesion Molecule-1 / Q000276:immunology* / Q000378:metabolism; D040542:Mechanotransduction, Cellular / Q000276:immunology*; D008856:Microscopy, Fluorescence; D019384:Nucleic Acid Synthesis Inhibitors / Q000494:pharmacology; D034622:RNA Interference; D064067:Rho Guanine Nucleotide Exchange Factors / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D015398:Signal Transduction / Q000276:immunology; D013314:Stress, Mechanical; D057705:Transendothelial and Transepithelial Migration / Q000276:immunology*
chemical_list: C577222:ARHGEF12 protein, human; D019384:Nucleic Acid Synthesis Inhibitors; D064067:Rho Guanine Nucleotide Exchange Factors; D018799:Intercellular Adhesion Molecule-1; D015638:Cytochalasin D