title: Eosinophil adhesion under flow conditions activates mechanosensitive signaling pathways in human endothelial cells.
abstract: Leukocyte transmigration can be affected by shear stress; however, the mechanisms by which shear stress modulates transmigration are unknown. We found that adhesion of eosinophils or an eosinophilic cell line to intereukin 4-stimulated endothelial cells led to a shear-dependent increase in endothelial cell intracellular calcium and increased phosphorylation of extracellular signal-regulated kinase (ERK) 2, but not c-Jun NH2-terminal kinase or p38 mitogen-activated protein kinase. Latex beads coated with antibodies were used to characterize the role of specific endothelial cell surface molecules in initiating signaling under shear conditions. We found that ligation of either vascular cell adhesion molecule-1 or E-selectin, but not major histocompatibility complex class I, induced a shear-dependent increase in ERK2 phosphorylation in cytokine-stimulated endothelial cells. Disassembly of the actin cytoskeleton with latrunculin A prevented ERK2 phosphorylation after adhesion under flow conditions, supporting a role for the cytoskeleton in mechano-sensing. Rapid phosphorylation of focal adhesion kinase and paxillin occurred under identical conditions, suggesting that focal adhesions were also involved in mechanotransduction. Finally, we found that Rho-associated protein kinase and calpain were both critical in the subsequent transendothelial migration of eosinophils under flow conditions. These data suggest that ligation of leukocyte adhesion molecules under flow conditions leads to mechanotransduction in endothelial cells, which can regulate subsequent leukocyte trafficking.
authors.affiliation: Department of Physiology and Biophysics, Immunology Research Group, University of Calgary, Calgary, Alberta, Canada T2N 4N1.
authors.forename: Susan L
authors.initials: SL
authors.lastname: Cuvelier
authors.forename: Smitha
authors.initials: S
authors.lastname: Paul
authors.forename: Neda
authors.initials: N
authors.lastname: Shariat
authors.forename: Pina
authors.initials: P
authors.lastname: Colarusso
authors.forename: Kamala D
authors.initials: KD
authors.lastname: Patel
mesh_terms: D000199:Actins / Q000378:metabolism; D000328:Adult; D002118:Calcium / Q000502:physiology; D002154:Calpain / Q000502:physiology; D002448:Cell Adhesion / Q000276:immunology; D002460:Cell Line; D002465:Cell Movement / Q000276:immunology* / Q000502:physiology; D003599:Cytoskeleton / Q000378:metabolism; D019040:E-Selectin / Q000378:metabolism; D042783:Endothelial Cells / Q000201:enzymology / Q000502:physiology*; D004730:Endothelium, Vascular / Q000166:cytology / Q000201:enzymology / Q000276:immunology; D004804:Eosinophils / Q000502:physiology*; D006801:Humans; D015847:Interleukin-4 / Q000502:physiology; D047908:Intracellular Signaling Peptides and Proteins; D040542:Mechanotransduction, Cellular / Q000276:immunology*; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000502:physiology; D011505:Protein-Tyrosine Kinases / Q000502:physiology; D019010:Vascular Cell Adhesion Molecule-1 / Q000378:metabolism; D054460:rho-Associated Kinases
chemical_list: D000199:Actins; D019040:E-Selectin; D047908:Intracellular Signaling Peptides and Proteins; D019010:Vascular Cell Adhesion Molecule-1; D015847:Interleukin-4; D011505:Protein-Tyrosine Kinases; D017346:Protein Serine-Threonine Kinases; D054460:rho-Associated Kinases; D019950:Mitogen-Activated Protein Kinase 1; D002154:Calpain; D002118:Calcium