title: An organotypic coculture model supporting proliferation and differentiation of medullary thymic epithelial cells and promiscuous gene expression.
abstract: Understanding intrathymic T cell differentiation has been greatly aided by the development of various reductionist in vitro models that mimic certain steps/microenvironments of this complex process. Most models focused on the faithful in vitro restoration of T cell differentiation and selection. In contrast, suitable in vitro models emulating the developmental pathways of the two major thymic epithelial cell lineages--cortical thymic epithelial cells and medullary thymic epithelial cells (mTECs)--are yet to be developed. In this regard, lack of an in vitro model mimicking the developmental biology of the mTEC lineage has hampered the molecular analysis of the so-called "promiscuous expression" of tissue-restricted genes, a key property of terminally differentiated mTECs. Based on the close biological relationship between the skin and thymus epithelial cell compartments, we adapted a three-dimensional organotypic coculture model, originally developed to provide a bona fide in vitro dermal equivalent, for the culture of isolated mTECs. This three-dimensional model preserves key features of mTECs: proliferation and terminal differentiation of CD80(lo), Aire(-) mTECs into CD80(hi), Aire(+) mTECs; responsiveness to RANKL; and sustained expression of FoxN1, Aire, and tissue-restricted genes in CD80(hi) mTECs. This in vitro culture model should facilitate the identification of molecular components and pathways involved in mTEC differentiation in general and in promiscuous gene expression in particular.
authors.affiliation: Division of Developmental Immunology, German Cancer Research Center, 69120 Heidelberg, Germany.
authors.forename: Sheena
authors.initials: S
authors.lastname: Pinto
authors.forename: Katrin
authors.initials: K
authors.lastname: Schmidt
authors.forename: Stefanie
authors.initials: S
authors.lastname: Egle
authors.forename: Hans-Jürgen
authors.initials: HJ
authors.lastname: Stark
authors.forename: Petra
authors.initials: P
authors.lastname: Boukamp
authors.forename: Bruno
authors.initials: B
authors.lastname: Kyewski
mesh_terms: D000818:Animals; D018122:B7-1 Antigen / Q000096:biosynthesis / Q000235:genetics; D018929:Cell Culture Techniques / Q000295:instrumentation / Q000379:methods*; D002455:Cell Division; D019070:Cell Lineage; D002478:Cells, Cultured / Q000166:cytology / Q000187:drug effects / Q000276:immunology; D018920:Coculture Techniques; D020405:Dermis / Q000166:cytology; D004847:Epithelial Cells / Q000166:cytology* / Q000187:drug effects; D005260:Female; D051523:Fibroblast Growth Factor 7 / Q000494:pharmacology; D005347:Fibroblasts / Q000166:cytology / Q000528:radiation effects; D051858:Forkhead Transcription Factors / Q000096:biosynthesis / Q000235:genetics; D005786:Gene Expression Regulation; D006801:Humans; D038041:Lymphopoiesis / Q000187:drug effects; D051379:Mice; D008810:Mice, Inbred C57BL; D008856:Microscopy, Fluorescence; D009924:Organ Culture Techniques / Q000295:instrumentation / Q000379:methods*; D009928:Organ Specificity; D011247:Pregnancy; D053245:RANK Ligand / Q000494:pharmacology; D013601:T-Lymphocytes / Q000166:cytology* / Q000187:drug effects; D060168:Thymocytes / Q000166:cytology* / Q000187:drug effects; D013950:Thymus Gland / Q000166:cytology*; D014157:Transcription Factors / Q000096:biosynthesis / Q000235:genetics; D000096927:AIRE Protein
chemical_list: D018122:B7-1 Antigen; D051523:Fibroblast Growth Factor 7; D051858:Forkhead Transcription Factors; D053245:RANK Ligand; D014157:Transcription Factors; D000096927:AIRE Protein; C090140:Whn protein