title: Meis1 is required for the maintenance of postnatal thymic epithelial cells.
abstract: Most epithelial tissues retain stem/progenitor cells to maintain homeostasis of the adult tissues; however, the existence of a thymic epithelial cell (TEC) progenitor capable of maintaining homeostasis of the postnatal thymus remains unclear. Here, we show that a cell population expressing high levels of Meis1, a homeodomain transcription factor, is enriched in TECs with an immature cellular phenotype. These TECs selectively express genes involved in embryonic thymic organogenesis and epithelial stem cell maintenance, and also have the potential to proliferate and differentiate into mature TEC populations. Furthermore, postnatal inactivation of Meis1 in TECs caused disorganization of the thymic architecture, which ultimately leads to premature disappearance of the thymus. There was an age-associated reduction in the proportion of the TEC population expressing high levels of Meis1, which may also be related to thymic involution. These findings indicate that Meis1 is potentially involved in the maintenance of postnatal TECs with progenitor activity that is required for homeostasis of the postnatal thymus.
authors.affiliation: Division of Development and Aging, Research Institute for Biomedical Sciences, Tokyo University of Science, Chiba, Japan.
authors.forename: Takehiro
authors.initials: T
authors.lastname: Hirayama
authors.affiliation: Division of Development and Aging, Research Institute for Biomedical Sciences, Tokyo University of Science, Chiba, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Asano
authors.affiliation: Division of Development and Aging, Research Institute for Biomedical Sciences, Tokyo University of Science, Chiba, Japan.
authors.forename: Hajime
authors.initials: H
authors.lastname: Iida
authors.affiliation: Center for Innovation in Immunoregulative Technology and Therapeutics, Kyoto University Graduate School of Medicine, Kyoto, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Watanabe
authors.affiliation: Department of Carcinogenesis, The Cancer Institute, Japanese Foundation for Cancer Research, Tokyo, Japan.
authors.forename: Takuro
authors.initials: T
authors.lastname: Nakamura
authors.affiliation: Division of Development and Aging, Research Institute for Biomedical Sciences, Tokyo University of Science, Chiba, Japan.
authors.forename: Ryo
authors.initials: R
authors.lastname: Goitsuka
mesh_terms: D000375:Aging / Q000378:metabolism; D000818:Animals; D000831:Animals, Newborn; D001284:Atrophy; D002454:Cell Differentiation; D060833:Cellular Microenvironment; D004847:Epithelial Cells / Q000166:cytology / Q000378:metabolism*; D017353:Gene Deletion; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism*; D008810:Mice, Inbred C57BL; D000075064:Myeloid Ecotropic Viral Integration Site 1 Protein; D009363:Neoplasm Proteins / Q000235:genetics / Q000378:metabolism*; D009928:Organ Specificity; D013950:Thymus Gland / Q000166:cytology*
chemical_list: D018398:Homeodomain Proteins; C000616392:Meis1 protein, mouse; D000075064:Myeloid Ecotropic Viral Integration Site 1 Protein; D009363:Neoplasm Proteins