title: Modulation of fibronectin and thymic stromal cell-dependent thymocyte maturation by retinoic acid.
abstract: Retinoic acid (RA) controls the differentiation of a variety of cell types, although its role in influencing T cell development and the mechanisms potentially involved have not been thoroughly investigated. To study the ability of RA to modulate T cell development, we established a thymic stromal cell line (TC-1S) that supports the phenotypic maturation of CD4-8- double negative (DN) or CD3-4-8- triple negative (TN) thymocyte precursors. Cocultures of either DN or TN thymocytes on a monolayer of TC-1S cells resulted in the appearance of thymocytes with a more mature phenotype (CD4+8+ double positive, CD4+ or CD8+ single positive, and CD3(low) cells). Double negative T cell contact with TC-1S cells also increased the production of fibronectin (FN) by the thymic stroma and the expression of the VLA-4 FN receptor on the DN cells. Ab-mediated inhibition of the interaction between FN and its receptors significantly reduced the level of induced T cell maturation. Addition of RA either to TC-1S cells alone or to the coculture with DN cells decreased stromal cell FN expression, antagonized DN cell-induced increase in stromal cell FN production and significantly inhibited in vitro thymocyte maturation. The effects of RA were likely mediated by RA acid receptors alpha and gamma expressed both in DN thymocytes and TC-1S cells. Together these data suggest that FN/VLA-4 interaction may be an important component of stromal cell-dependent thymocyte phenotypic differentiation and that this interaction can be one of the targets for the influence of RA in T cell development.
authors.affiliation: Department of Experimental Medicine, University La Sapienza, Rome, Italy.
authors.forename: D
authors.initials: D
authors.lastname: Meco
authors.forename: S
authors.initials: S
authors.lastname: Scarpa
authors.forename: M
authors.initials: M
authors.lastname: Napolitano
authors.forename: M
authors.initials: M
authors.lastname: Maroder
authors.forename: D
authors.initials: D
authors.lastname: Bellavia
authors.forename: R
authors.initials: R
authors.lastname: De Maria
authors.forename: M
authors.initials: M
authors.lastname: Ragano-Caracciolo
authors.forename: L
authors.initials: L
authors.lastname: Frati
authors.forename: A
authors.initials: A
authors.lastname: Modesti
authors.forename: A
authors.initials: A
authors.lastname: Gulino
mesh_terms: D000818:Animals; D001483:Base Sequence; D017252:CD3 Complex / Q000032:analysis; D015704:CD4 Antigens / Q000032:analysis; D016827:CD8 Antigens / Q000032:analysis; D002448:Cell Adhesion; D002454:Cell Differentiation / Q000187:drug effects; D002478:Cells, Cultured; D017931:DNA Primers / Q000737:chemistry; D005353:Fibronectins / Q000378:metabolism*; D015870:Gene Expression / Q000187:drug effects; D066298:In Vitro Techniques; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000235:genetics; D018168:Receptors, Retinoic Acid / Q000378:metabolism; D016029:Receptors, Very Late Antigen / Q000378:metabolism; D013950:Thymus Gland / Q000166:cytology* / Q000276:immunology; D014212:Tretinoin / Q000494:pharmacology*
chemical_list: D017252:CD3 Complex; D015704:CD4 Antigens; D016827:CD8 Antigens; D017931:DNA Primers; D005353:Fibronectins; D012333:RNA, Messenger; D018168:Receptors, Retinoic Acid; D016029:Receptors, Very Late Antigen; D014212:Tretinoin