title: Impaired chemokine-induced migration during T-cell development in the absence of Jak 3.
abstract: The arrival of bone marrow T-cell progenitors to the thymus, and the directed migration of thymocytes, are thought to be regulated by the expression of chemokines and their receptors. Recent data has shown that the Jak/Stat signalling pathway is involved in chemokine receptor signalling. We have investigated the role of Jak 3 in chemokine-mediated signalling in the thymus using Jak 3(-/-) mice. These mice show defects in T-cell development, as well as in peripheral T-cell function, resulting in a hypoplastic thymus and an altered T-cell homeostasis. Here we demonstrate, for the first time, that bone marrow progenitors and thymocytes from Jak 3(-/-) mice have decreased chemotactic responses to CXCL12 and CCL25. We also show that Jak 3 is involved in signalling through CCR9 and CXCR4, and that specific inhibition of Jak 3 in wild-type progenitors and thymocytes decreases their chemotactic responses towards CCL25 and CXCL12. Finally, quantitative reverse transcription-polymerase chain reaction analysis showed that thymocytes from Jak 3(-/-) mice express similar levels of CXCR4 and CCR9 compared to wild-type mice. Altogether, deficient CCL25- and CXCL12-induced migration could result in a homing defect of T-cell progenitors to the thymus, as well as in a deficient thymocyte migration through the thymic stroma. Our results strongly suggest that the absence of Jak 3 affects T-cell development, not only through an impaired interleukin-7 receptor (IL-7R)-mediated signalling, but also through impaired chemokine-mediated responses, which are crucial for thymocyte migration and differentiation.
authors.affiliation: Departamento de Inmunología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México. soldevi@servidor.unam.mx
authors.forename: Gloria
authors.initials: G
authors.lastname: Soldevila
authors.forename: Ileana
authors.initials: I
authors.lastname: Licona
authors.forename: Alfonso
authors.initials: A
authors.lastname: Salgado
authors.forename: Marcela
authors.initials: M
authors.lastname: Ramírez
authors.forename: Ramsés
authors.initials: R
authors.lastname: Chávez
authors.forename: Eduardo
authors.initials: E
authors.lastname: García-Zepeda
mesh_terms: D000818:Animals; D054377:Chemokine CXCL12; D018925:Chemokines / Q000276:immunology*; D019742:Chemokines, CC / Q000276:immunology; D019743:Chemokines, CXC / Q000276:immunology; D002634:Chemotaxis, Leukocyte / Q000187:drug effects / Q000276:immunology*; D004306:Dose-Response Relationship, Immunologic; D006412:Hematopoietic Stem Cells / Q000276:immunology; D053616:Janus Kinase 3; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D010766:Phosphorylation; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000276:immunology*; D011799:Quinazolines / Q000494:pharmacology; D054388:Receptors, CCR; D019718:Receptors, CXCR4 / Q000378:metabolism; D019707:Receptors, Chemokine / Q000378:metabolism; D013601:T-Lymphocytes / Q000276:immunology*; D013950:Thymus Gland / Q000276:immunology; D014443:Tyrosine / Q000378:metabolism
chemical_list: C119309:CC chemokine receptor 9; C491541:Ccl25 protein, mouse; D054377:Chemokine CXCL12; D018925:Chemokines; D019742:Chemokines, CC; D019743:Chemokines, CXC; C515256:Cxcl12 protein, mouse; D011799:Quinazolines; D054388:Receptors, CCR; D019718:Receptors, CXCR4; D019707:Receptors, Chemokine; C116180:WHI P131; D014443:Tyrosine; D011505:Protein-Tyrosine Kinases; C507935:Jak3 protein, mouse; D053616:Janus Kinase 3