title: In vivo analysis of uropod function during physiological T cell trafficking.
abstract: Migrating lymphocytes acquire a polarized phenotype with a leading and a trailing edge, or uropod. Although in vitro experiments in cell lines or activated primary cell cultures have established that Rho-p160 coiled-coil kinase (ROCK)-myosin II-mediated uropod contractility is required for integrin de-adhesion on two-dimensional surfaces and nuclear propulsion through narrow pores in three-dimensional matrices, less is known about the role of these two events during the recirculation of primary, nonactivated lymphocytes. Using pharmacological antagonists of ROCK and myosin II, we report that inhibition of uropod contractility blocked integrin-independent mouse T cell migration through narrow, but not large, pores in vitro. T cell crawling on chemokine-coated endothelial cells under shear was severely impaired by ROCK inhibition, whereas transendothelial migration was only reduced through endothelial cells with high, but not low, barrier properties. Using three-dimensional thick-tissue imaging and dynamic two-photon microscopy of T cell motility in lymphoid tissue, we demonstrated a significant role for uropod contractility in intraluminal crawling and transendothelial migration through lymph node, but not bone marrow, endothelial cells. Finally, we demonstrated that ICAM-1, but not anatomical constraints or integrin-independent interactions, reduced parenchymal motility of inhibitor-treated T cells within the dense lymphoid microenvironment, thus assigning context-dependent roles for uropod contraction during lymphocyte recirculation.
authors.affiliation: Theodor Kocher Institute, University of Bern, 3012 Bern, Switzerland.
authors.forename: Silvia F
authors.initials: SF
authors.lastname: Soriano
authors.forename: Miroslav
authors.initials: M
authors.lastname: Hons
authors.forename: Kathrin
authors.initials: K
authors.lastname: Schumann
authors.forename: Varsha
authors.initials: V
authors.lastname: Kumar
authors.forename: Timo J
authors.initials: TJ
authors.lastname: Dennier
authors.forename: Ruth
authors.initials: R
authors.lastname: Lyck
authors.forename: Michael
authors.initials: M
authors.lastname: Sixt
authors.forename: Jens V
authors.initials: JV
authors.lastname: Stein
mesh_terms: D000818:Animals; D016764:Cell Polarity / Q000187:drug effects / Q000276:immunology; D002634:Chemotaxis, Leukocyte / Q000187:drug effects / Q000276:immunology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D005455:Fluorescent Antibody Technique; D021621:Imaging, Three-Dimensional; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D024462:Myosin Type II / Q000378:metabolism; D011554:Pseudopodia / Q000187:drug effects / Q000378:metabolism*; D013601:T-Lymphocytes / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism*; D057705:Transendothelial and Transepithelial Migration / Q000187:drug effects / Q000276:immunology; D054460:rho-Associated Kinases / Q000378:metabolism
chemical_list: D004791:Enzyme Inhibitors; D054460:rho-Associated Kinases; D024462:Myosin Type II