CD28 and NKG2D-mediated costimulation regulates CD8+ T cell chemotaxis through different signaling pathways
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1
Hospital Universitario Central de Asturias, Immunology Department, Spain
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2
Universidad de Oviedo, Facultad de Medicina, Spain
Introduction: CD28 is the prototypical costimulatory receptor in T cells, which propagates its signals through the YMNM signaling motif. NKG2D is a transmembrane receptor mainly expressed on NK cells and CD8+ T cells. It associates with DAP10, which contains a YINM motif, similar to CD28. Here we study the potential role of NKG2D as a costimulatory molecule in CD8+ T cell chemotactic response.
Material and methods: Human CD8+ T cells were assayed for their ability to migrate towards a CXCL12 gradient upon stimulation with anti-CD3, anti-CD28 and anti-NKG2D alone or in combinations. The activity of the Rho GTPases Rac1 and Cdc42 was analyzed by G-LISA. N-WASp was knocked-down using siRNA. Pharmacological inhibition of N-WASp by wiskostatin was used to analyze proteins involved in TCR signaling and cytoskeleton dynamics by western blot.
Results: Costimulation via CD28 and NKG2D inhibited cell migration. Rac1 is activated upon T cell receptor activation and costimulation through CD28 and NKG2D, whereas Cdc42 is activated only upon CD3/NKG2D activation. Knock-down of N-WASp partially abolished CD3/NKG2D-mediated impairment of T-cell chemotaxis. Vav, ERK1/2 and ERM proteins are regulated by CD3-mediated signaling, and pretreatment with wiskostatin did not affect their phosphorylation status. Costimulation of the TCR together with CD28 or NKG2D induces cofilin dephosphorylation. Administration of wiskostatin further decreased upon CD3/NKG2D activation, but not after CD3/CD28 engagement.
Conclusions: Costimulation via CD28 and NKG2D inhibits CD8+ T cell migration through different signaling pathways. CD3/NKG2D stimulation activates the Cdc42/N-WASp axis, and N-WASp is required for CD3/NKG2D-mediated inhibition of CD8+ T cell chemotaxis.
Acknowledgements
This work was supported by grants from the Red de Investigación Renal (REDinREN; RD 12/0021) and from Spanish Fondo de Investigaciones Sanitarias-Fondos FEDER European Union (PI08-0566 and PI12/02587). E.S.P. was supported by a “Severo Ochoa” fellowship (FICYT; Asturias, Spain). E.C.M. was supported by the Clarín program (FICYT, Asturias, Spain).
Keywords:
NKG2D,
Chemotaxis,
CD8+T cells,
cdc42 GTP-Binding Protein,
costimulatory molecules,
CD28
Conference:
15th International Congress of Immunology (ICI), Milan, Italy, 22 Aug - 27 Aug, 2013.
Presentation Type:
Abstract
Topic:
Immune receptors and signaling
Citation:
Serrano-Pertierra
E,
Cernuda-Morollón
E and
López-Larrea
C
(2013). CD28 and NKG2D-mediated costimulation regulates CD8+ T cell chemotaxis through different signaling pathways.
Front. Immunol.
Conference Abstract:
15th International Congress of Immunology (ICI).
doi: 10.3389/conf.fimmu.2013.02.00297
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Received:
12 Mar 2013;
Published Online:
22 Aug 2013.
*
Correspondence:
Dr. Carlos López-Larrea, Hospital Universitario Central de Asturias, Immunology Department, Oviedo, Asturias, 33006, Spain, inmuno@hca.es