title: Diacylglycerol kinase zeta negatively regulates CXCR4-stimulated T lymphocyte firm arrest to ICAM-1 under shear flow.
abstract: T lymphocyte arrest within microvasculature is an essential process in immune surveillance and the adaptive immune response. Integrins and chemokines coordinately regulate when and where T cells stop under flow via chemokine-triggered inside-out activation of integrins. Diacylglycerol kinases (DGKs) regulate the levels of diacylglycerol (DAG) which in turn determine the activation of guanine nucleotide exchange factors (GEFs) and Ras proximity 1 (Rap1) molecules crucial to the activation of integrin lymphocyte function-associated antigen 1 (LFA-1). However, how the level of DGK regulates chemokine-stimulated LFA-1-mediated T cell arrest under flow is unknown. Using a combination of experiment and computational modeling, we demonstrate that DGKζ is a crucial regulator of CXCL12-triggered T cell arrest on surfaces presenting inter-cellular adhesion molecule 1 (ICAM-1). Using flow chamber assays, we found that the deficiency of DGKζ in T cells significantly increased firm arrest to ICAM-1-coated substrates and shortened the time to stop without altering the rolling velocity. These results suggest that DGKζ levels affect LFA-1-mediated T cell firm arrest, but not P-selectin-mediated rolling during CXCL12 stimulation. We accurately simulated the role of DGKζ in firm arrest of T cells computationally using an Integrated-Signaling Adhesive Dynamics (ISAD). In the absence of DGK catalytic reaction, the model cells rolled for a significantly shorter time before arrest, compared to when DGK molecules were present. Predictions of our model for T cell arrest quantitatively match experimental results. Overall these results demonstrate that DGKζ is a negative regulator of CXCL12-triggered inside-out activation of LFA-1 and firm adhesion of T cells under shear flow.
authors.affiliation: Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, USA.
authors.forename: Dooyoung
authors.initials: D
authors.lastname: Lee
authors.forename: Jiyeon
authors.initials: J
authors.lastname: Kim
authors.forename: Michael T
authors.initials: MT
authors.lastname: Beste
authors.forename: Gary A
authors.initials: GA
authors.lastname: Koretzky
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Hammer
mesh_terms: D056704:Adaptive Immunity / Q000276:immunology; D000818:Animals; D002448:Cell Adhesion / Q000502:physiology; D003198:Computer Simulation; D019852:Diacylglycerol Kinase / Q000172:deficiency / Q000276:immunology / Q000378:metabolism*; D018799:Intercellular Adhesion Molecule-1 / Q000276:immunology / Q000378:metabolism*; D016169:Lymphocyte Function-Associated Antigen-1 / Q000276:immunology / Q000378:metabolism; D051379:Mice; D018345:Mice, Knockout; D008858:Microscopy, Phase-Contrast; D008954:Models, Biological; D019718:Receptors, CXCR4 / Q000276:immunology / Q000378:metabolism*; D015398:Signal Transduction; D013601:T-Lymphocytes / Q000166:cytology / Q000201:enzymology* / Q000276:immunology
chemical_list: C514936:CXCR4 protein, mouse; D016169:Lymphocyte Function-Associated Antigen-1; D019718:Receptors, CXCR4; D018799:Intercellular Adhesion Molecule-1; D019852:Diacylglycerol Kinase; C512480:diacylglycerol kinase zeta, mouse