title: Impaired migration of NOD mouse thymocytes: a fibronectin receptor-related defect.
abstract: We previously showed intrathymic alterations in non-obese diabetic (NOD) mice, including the appearance of giant perivascular spaces, filled with mature thymocytes, intermingled with an extracellular matrix network. This raised the hypothesis of a defect in thymocyte migration with partial arrest of exiting thymocytes in the perivascular spaces. Herein, we investigated the expression of receptors for fibronectin [very late antigen (VLA)-4 and VLA-5] and laminin (VLA-6), known to play a role in thymocyte migration. When compared with two normal and one other autoimmune mouse strains, a decrease of VLA-5 expression in NOD thymocytes was noticed, being firstly observed in late CD4/CD8 double-negative cells, and more pronounced in mature CD4(+) and CD8(+) thymocytes. Functionally, thymocyte exit from the lymphoepithelial complexes, the thymic nurse cells, was reduced. Moreover, NOD thymocyte adhesion to thymic epithelial cells as well as to fibronectin was diminished, and so was the migration of NOD thymocytes through fibronectin-containing transwell chambers. In situ, intra-perivascular space thymocytes were VLA-5-negative, suggesting a correlation between the thymocyte arrest within these structures and loss of VLA-5 expression. Overall, our data reveal impairment in NOD thymocyte migration, and correspond to the first demonstration of a functional fibronectin receptor defect in the immune system.
authors.affiliation: Laboratory of Cell Biology, Department of Ultrastructure and Cell Biology, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil.
authors.forename: Vinícius
authors.initials: V
authors.lastname: Cotta-de-Almeida
authors.forename: Déa Maria Serra
authors.initials: DM
authors.lastname: Villa-Verde
authors.forename: Françoise
authors.initials: F
authors.lastname: Lepault
authors.forename: Jean-Marie
authors.initials: JM
authors.lastname: Pléau
authors.forename: Mireille
authors.initials: M
authors.lastname: Dardenne
authors.forename: Wilson
authors.initials: W
authors.lastname: Savino
mesh_terms: D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology* / Q000378:metabolism; D018414:CD8-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology* / Q000378:metabolism; D002448:Cell Adhesion / Q000276:immunology; D002465:Cell Movement / Q000276:immunology*; D003433:Crosses, Genetic; D005260:Female; D005434:Flow Cytometry; D005786:Gene Expression Regulation / Q000276:immunology; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D016688:Mice, Inbred NOD; D012313:RNA / Q000737:chemistry / Q000235:genetics; D017469:Receptors, Fibronectin / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology*; D017474:Receptors, Laminin / Q000235:genetics / Q000276:immunology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013047:Specific Pathogen-Free Organisms; D013950:Thymus Gland / Q000166:cytology* / Q000276:immunology / Q000378:metabolism
chemical_list: D017469:Receptors, Fibronectin; D017474:Receptors, Laminin; D012313:RNA