title: EphB2-mediated interactions are essential for proper migration of T cell progenitors during fetal thymus colonization.
abstract: The ephrin-Eph ligand receptor pair is known to control the repulsion/adhesion process in different tissues, including the immune system. Herein, we evaluated the role of EphB2 receptors in T cell progenitor migration during in vitro thymus colonization and to ECM or chemokine stimuli. EphB2 and their ligands, ephrin-B1 and ephrin-B2, are expressed in BM-derived progenitors, and EphB2(-/-) cells had diminished thymus colonization capacity. Conversely, EphB2(LacZ) cells, which maintain a preserved ephrin-binding domain, were capable of colonizing WT thymuses similarly to WT progenitors, highlighting the importance of reverse signals transmitted to normal fetal thymus. However, the EphB2 receptor expressed by microenvironmental cells also drives progenitor immigration, as recolonization of EphB2-deficient fetal thymuses was compromised profoundly. Additionally, we observed lower depositions of ECM and chemokines on EphB2-deficient thymuses but no changes in their receptor expression on BM-derived progenitors and developing thymocytes. Migration of EphB2-deficient progenitors and thymocytes was also reduced through ECM or chemokine stimuli. Furthermore, ephrin-B1 costimulation also inhibited haptotaxis and chemotaxis of WT but not EphB2(LacZ) cells, demonstrating the specific involvement of EphB2 signaling on T cell progenitor migration. Our data suggest the relevance of a nonactivated EphB2 for regulating T cell progenitor migration and its modulation upon ephrin-B engagement.
authors.affiliation: Department of Cell Biology, Faculty of Biology, Complutense University, C/José Antonio Nováis, sn, 28040 Madrid, Spain.
authors.forename: Marco A
authors.initials: MA
authors.lastname: Stimamiglio
authors.forename: Eva
authors.initials: E
authors.lastname: Jiménez
authors.forename: Suse D
authors.initials: SD
authors.lastname: Silva-Barbosa
authors.forename: David
authors.initials: D
authors.lastname: Alfaro
authors.forename: José J
authors.initials: JJ
authors.lastname: García-Ceca
authors.forename: Juan J
authors.initials: JJ
authors.lastname: Muñoz
authors.forename: Teresa
authors.initials: T
authors.lastname: Cejalvo
authors.forename: Wilson
authors.initials: W
authors.lastname: Savino
authors.forename: Agustín
authors.initials: A
authors.lastname: Zapata
mesh_terms: D000818:Animals; D001854:Bone Marrow Cells / Q000166:cytology; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology; D002450:Cell Communication / Q000276:immunology*; D002462:Cell Membrane / Q000378:metabolism; D002465:Cell Movement / Q000276:immunology*; D018925:Chemokines / Q000378:metabolism; D003114:Colony-Forming Units Assay; D036387:Ephrin-B1 / Q000378:metabolism; D036388:Ephrin-B2 / Q000172:deficiency / Q000378:metabolism*; D016326:Extracellular Matrix Proteins / Q000378:metabolism; D005333:Fetus / Q000166:cytology*; D008024:Ligands; D051379:Mice; D036183:Receptor, EphB2 / Q000378:metabolism; D011961:Receptors, Fc / Q000378:metabolism; D013234:Stem Cells / Q000166:cytology* / Q000276:immunology; D013601:T-Lymphocytes / Q000166:cytology* / Q000276:immunology; D013950:Thymus Gland / Q000166:cytology / Q000196:embryology* / Q000276:immunology
chemical_list: D018925:Chemokines; D036387:Ephrin-B1; D036388:Ephrin-B2; D016326:Extracellular Matrix Proteins; D008024:Ligands; D011961:Receptors, Fc; D036183:Receptor, EphB2