An organized and functional thymus generated from FOXN1-reprogrammed fibroblasts
Nicholas Bredenkamp, Svetlana Ulyanchenko, Kathy Emma O'Neill, Nancy Ruth Manley, Harsh Jayesh Vaidya, Catherine Clare Blackburn, Nicholas Bredenkamp, Svetlana Ulyanchenko, Kathy Emma O'Neill, Nancy Ruth Manley, Harsh Jayesh Vaidya, Catherine Clare Blackburn
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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References
- Graf T, Enver T. Forcing cells to change lineages. Nature. 2009;462:587–594.
- Nehls M, et al. Two genetically separable steps in the differentiation of thymic epithelium. Science. 1996;272:886–889.
- Blackburn CC, et al. The nu gene acts cell-autonomously and is required for differentiation of thymic epithelial progenitors. Proc Natl Acad Sci USA. 1996;93:5742– 5746.
- Ritter MA, Boyd RL. Development in the thymus: it takes two to tango. Immunol Today. 1993;14:462–469.
- Miller JFAP. Immunological function of the thymus. Lancet. 1961;2:748– 749.
- Chinn IK, Blackburn CC, Manley NR, Sempowski GD. Changes in primary lymphoid organs with aging. Semin Immunol. 2012;24:309–320.
- Lynch HE, et al. Thymic involution and immune reconstitution. Trends Immunol. 2009;30:366–373.
- Manley NR, Richie ER, Blackburn CC, Condie BG, Sage J. Structure and function of the thymic microenvironment. Frontiers Biosci. 2011;16:2461–2477.
- Nowell CS, et al. Foxn1 regulates lineage progression in cortical and medullary thymic epithelial cells but is dispensable for medullary sublineage divergence. PLoS Genet. 2011;7:e1002348.
- Bleul CC, et al. Formation of a functional thymus initiated by a postnatal epithelial progenitor cell. Nature. 2006;441:992–996.
- Markert ML, et al. Transplantation of thymus tissue in complete DiGeorge Syndrome. The New England J Med. 1999;341:1180–1189.
- Lai L, Jin J. Generation of thymic epithelial cell progenitors by mouse embryonic stem cells. Stem Cells. 2009;27:3012–3020.
- Lai L, et al. Mouse embryonic stem cell-derived thymic epithelial cell progenitors enhance T-cell reconstitution after allogeneic bone marrow transplantation. Blood. 2011;118:3410–3418.
- Inami Y, et al. Differentiation of induced pluripotent stem cells to thymic epithelial cells by phenotype. Immunol Cell Biol. 2011;89:314–321.
- Parent AV, et al. Generation of functional thymic epithelium from human embryonic stem cells that supports host T cell development. Cell Stem Cell. 2013;13:219–229.
- Sun X, et al. Directed differentiation of human embryonic stem cells into thymic epithelial progenitor-like cells reconstitutes the thymic microenvironment in vivo. Cell Stem Cell. 2013;13:230–236.
- Mathis D, Benoist C. Aire. Annu Rev Immunol. 2009;27:287–312.
- Klug DB, et al. Interdependence of cortical thymic epithelial cell differentiation and T-lineage commitment. Proc Natl Acad Sci USA. 1998;95:11822–11827.
- Manley NR, Condie BG. Transcriptional regulation of thymus organogenesis and thymic epithelial cell differentiation. Prog Mol Biol Transl Sci. 2010;92:103–120.
- Weiner L, et al. Dedicated epithelial recipient cells determine pigmentation patterns. Cell. 2007;130:932–942.
- Allman D, et al. Thymopoiesis independent of common lymphoid progenitors. Nature Immunol. 2003;4:168–174.
- Klug DB, Carter C, Gimenez-Conti IB, Richie ER. Cutting edge: thymocyte-independent and thymocyte-dependent phases of epithelial patterning in the fetal thymus. J Immunol. 2002;169:2842–2845.
- Revest JM, Suniara RK, Kerr K, Owen JJ, Dickson C. Development of the thymus requires signaling through the fibroblast growth factor receptor R2-IIIb. J Immunol. 2001;167:1954–1961.
- Rubin JS, et al. Purification and characterization of a newly identified growth factor specific for epithelial cells. Proc Natl Acad Sci U S A. 1989;86:802–806.
- Adolfsson J, et al. Identification of Flt3+ lympho-myeloid stem cells lacking erythro-megakaryocytic potential a revised road map for adult blood lineage commitment. Cell. 2005;121:295–306.
- Luc S, et al. The earliest thymic T cell progenitors sustain B cell and myeloid lineage potential. Nature Immunol. 2012;13:412–419.
- Schmitt TM, et al. Induction of T cell development and establishment of T cell competence from embryonic stem cells differentiated in vitro. Nature Immunol. 2004;5:410–417.
- La Motte-Mohs RN, Herer E, Zuniga-Pflucker JC. Induction of T-cell development from human cord blood hematopoietic stem cells by Delta-like 1 in vitro. Blood. 2005;105:1431–1439.
- Bennett AR, et al. Identification and characterization of thymic epithelial progenitor cells. Immunity. 2002;16:803–814.
- Sheridan JM, Taoudi S, Medvinsky A, Blackburn CC. A novel method for the generation of reaggregated organotypic cultures that permits juxtaposition of defined cell populations. Genesis. 2009;47:346–351.
- Auerbach R. Morphogenetic interactions in the development of the mouse thymus gland. Dev Biol. 1960;2:271– 284.
- Jenkinson WE, Rossi SW, Parnell SM, Jenkinson EJ, Anderson G. PDGFRalpha-expressing mesenchyme regulates thymus growth and the availability of intrathymic niches. Blood. 2007;109:954–960.
- Abramson J, Giraud M, Benoist C, Mathis D. Aire's partners in the molecular control of immunological tolerance. Cell. 2010;140:123–135.
- Shakib S, et al. Checkpoints in the development of thymic cortical epithelial cells. J Immunol. 2009;182:130–137.
- Murata S, et al. Regulation of CD8+ T cell development by thymus-specific proteasomes. Science. 2007;316:1349–1353.
- Schmitt TM, Zuniga-Pflucker JC. Induction of T cell development from hematopoietic progenitor cells by delta-like-1 in vitro. Immunity. 2002;17:749–756.
- Dervovic DD, et al. Cellular and molecular requirements for the selection of in vitro-generated CD8 T cells reveal a role for Notch. J Immunol. 2013;191:1704–1715.
- Hameyer D, et al. Toxicity of ligand-dependent Cre recombinases and generation of a conditional Cre deleter mouse allowing mosaic recombination in peripheral tissues. Physiol Genomics. 2007;31:32–41.
- Wallace HA, et al. Manipulating the mouse genome to engineer precise functional syntenic replacements with human sequence. Cell. 2007;128:197–209.
- Gray DH, et al. Unbiased analysis, enrichment and purification of thymic stromal cells. J Immunol Methods. 2008;329:56–66.
Source: PubMed