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Vaidya HJ, Briones Leon A, Blackburn CC. FOXN1 in thymus organogenesis and development. Eur J Immunol 2017; 46:1826-37. [PMID: 27378598 PMCID: PMC4988515 DOI: 10.1002/eji.201545814] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Revised: 06/21/2016] [Accepted: 06/29/2016] [Indexed: 01/11/2023]
Abstract
Development of the primary T‐cell repertoire takes place in the thymus. The linked processes of T‐cell differentiation and T‐cell repertoire selection each depend on interactions between thymocytes and thymic stromal cells; in particular, with the epithelial cells of the cortical and medullary thymic compartments (cortical and medullary thymic epithelial cells; cTECs and mTECs, respectively). The importance of the thymic epithelial cell lineage in these processes was revealed in part through analysis of nude (nu/nu) mice, which are congenitally hairless and athymic. The nude phenotype results from null mutation of the forkhead transcription factor FOXN1, which has emerged as a pivotal regulator both of thymus development and homeostasis. FOXN1 has been shown to play critical roles in thymus development, function, maintenance, and even regeneration, which positions it as a master regulator of thymic epithelial cell (TEC) differentiation. In this review, we discuss current understanding of the regulation and functions of FOXN1 throughout thymus ontogeny, from the earliest stages of organogenesis through homeostasis to age‐related involution, contextualising its significance through reference to other members of the wider Forkhead family.
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Affiliation(s)
- Harsh Jayesh Vaidya
- MRC Centre for Regenerative Medicine, Institute for Stem Cell Research, School of Biological Sciences, Edinburgh, UK
| | - Alberto Briones Leon
- MRC Centre for Regenerative Medicine, Institute for Stem Cell Research, School of Biological Sciences, Edinburgh, UK
| | - C Clare Blackburn
- MRC Centre for Regenerative Medicine, Institute for Stem Cell Research, School of Biological Sciences, Edinburgh, UK
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Bredenkamp N, Ulyanchenko S, O'Neill KE, Manley NR, Vaidya HJ, Blackburn CC. An organized and functional thymus generated from FOXN1-reprogrammed fibroblasts. Nat Cell Biol 2014; 16:902-8. [PMID: 25150981 PMCID: PMC4153409 DOI: 10.1038/ncb3023] [Citation(s) in RCA: 115] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Accepted: 07/10/2014] [Indexed: 12/25/2022]
Abstract
A central goal of regenerative medicine is to generate transplantable organs from cells derived or expanded in vitro. Although numerous studies have demonstrated the production of defined cell types in vitro, the creation of a fully intact organ has not been reported. The transcription factor forkhead box N1 (FOXN1) is critically required for development of thymic epithelial cells (TECs), a key cell type of the thymic stroma. Here, we show that enforced Foxn1 expression is sufficient to reprogramme fibroblasts into functional TECs, an unrelated cell type across a germ-layer boundary. These FOXN1-induced TECs (iTECs) supported efficient development of both CD4(+) and CD8(+) T cells in vitro. On transplantation, iTECs established a complete, fully organized and functional thymus, that contained all of the TEC subtypes required to support T-cell differentiation and populated the recipient immune system with T cells. iTECs thus demonstrate that cellular reprogramming approaches can be used to generate an entire organ, and open the possibility of widespread use of thymus transplantation to boost immune function in patients.
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Affiliation(s)
- Nicholas Bredenkamp
- 1] Medical Research Council Centre for Regenerative Medicine, Institute for Stem Cell Research, School of Biological Sciences, University of Edinburgh, SCRM Building, 5 Little France Drive, Edinburgh EH16 4UU, UK [2]
| | - Svetlana Ulyanchenko
- Medical Research Council Centre for Regenerative Medicine, Institute for Stem Cell Research, School of Biological Sciences, University of Edinburgh, SCRM Building, 5 Little France Drive, Edinburgh EH16 4UU, UK
| | - Kathy Emma O'Neill
- Medical Research Council Centre for Regenerative Medicine, Institute for Stem Cell Research, School of Biological Sciences, University of Edinburgh, SCRM Building, 5 Little France Drive, Edinburgh EH16 4UU, UK
| | - Nancy Ruth Manley
- Department of Genetics, University of Georgia, Athens, Georgia 30602, USA
| | - Harsh Jayesh Vaidya
- Medical Research Council Centre for Regenerative Medicine, Institute for Stem Cell Research, School of Biological Sciences, University of Edinburgh, SCRM Building, 5 Little France Drive, Edinburgh EH16 4UU, UK
| | - Catherine Clare Blackburn
- Medical Research Council Centre for Regenerative Medicine, Institute for Stem Cell Research, School of Biological Sciences, University of Edinburgh, SCRM Building, 5 Little France Drive, Edinburgh EH16 4UU, UK
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