title: Label retention identifies a multipotent mesenchymal stem cell-like population in the postnatal thymus.
abstract: Thymic microenvironments are essential for the proper development and selection of T cells critical for a functional and self-tolerant adaptive immune response. While significant turnover occurs, it is unclear whether populations of adult stem cells contribute to the maintenance of postnatal thymic epithelial microenvironments. Here, the slow cycling characteristic of stem cells and their property of label-retention were used to identify a K5-expressing thymic stromal cell population capable of generating clonal cell lines that retain the capacity to differentiate into a number of mesenchymal lineages including adipocytes, chondrocytes and osteoblasts suggesting a mesenchymal stem cell-like phenotype. Using cell surface analysis both culture expanded LRCs and clonal thymic mesenchymal cell lines were found to express Sca1, PDGFRα, PDGFRβ,CD29, CD44, CD49F, and CD90 similar to MSCs. Sorted GFP-expressing stroma, that give rise to TMSC lines, contribute to thymic architecture when reaggregated with fetal stroma and transplanted under the kidney capsule of nude mice. Together these results show that the postnatal thymus contains a population of mesenchymal stem cells that can be maintained in culture and suggests they may contribute to the maintenance of functional thymic microenvironments.
authors: Department of Biology, The City College of New York, CUNY, New York, New York, United States of America.
authors: Masako
authors: M
authors: Osada
authors: Varan J
authors: VJ
authors: Singh
authors: Kenmin
authors: K
authors: Wu
authors: Derek B
authors: DB
authors: Sant'Angelo
authors: Mark
authors: M
authors: Pezzano
mesh_terms: D000818:Animals; D000950:Antigens, Ly / Q000378:metabolism; D001483:Base Sequence; D002454:Cell Differentiation; D019070:Cell Lineage; D017690:Cell Transplantation; D005260:Female; D049452:Green Fluorescent Proteins / Q000378:metabolism; D018960:Hyaluronan Receptors / Q000378:metabolism; D039503:Integrin alpha6 / Q000378:metabolism; D019012:Integrin beta1 / Q000378:metabolism; D007668:Kidney / Q000473:pathology; D008297:Male; D059630:Mesenchymal Stem Cells / Q000166:cytology*; D051379:Mice; D008810:Mice, Inbred C57BL; D008819:Mice, Nude; D008969:Molecular Sequence Data; D039902:Multipotent Stem Cells / Q000166:cytology*; D020796:Receptor, Platelet-Derived Growth Factor alpha / Q000378:metabolism; D020797:Receptor, Platelet-Derived Growth Factor beta / Q000378:metabolism; D013601:T-Lymphocytes / Q000166:cytology; D018800:Thy-1 Antigens / Q000378:metabolism; D013950:Thymus Gland / Q000166:cytology*
chemical_list: D000950:Antigens, Ly; C476399:Cd44 protein, mouse; D018960:Hyaluronan Receptors; D039503:Integrin alpha6; D019012:Integrin beta1; C526827:Ly6 protein, mouse; D018800:Thy-1 Antigens; D049452:Green Fluorescent Proteins; D020796:Receptor, Platelet-Derived Growth Factor alpha; D020797:Receptor, Platelet-Derived Growth Factor beta