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McLelland BT, Gravano D, Castillo J, Montoy S, Manilay JO. Enhanced isolation of adult thymic epithelial cell subsets for multiparameter flow cytometry and gene expression analysis. J Immunol Methods 2011; 367:85-94. [PMID: 21354161 DOI: 10.1016/j.jim.2011.02.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2010] [Revised: 12/13/2010] [Accepted: 02/18/2011] [Indexed: 12/17/2022]
Abstract
The epithelial cells (TECs) are microenvironmental niche cells which support T lymphocyte development in the thymus. Most studies of TEC biology have focused on TEC at the fetal stage of development, whereas the biology of adult-stage TECs is not as well-understood. Delineating the molecular mechanisms that control adult TEC differentiation has implications for the success of T-lymphocyte based therapies for autoimmune diseases and induction of immunological tolerance to stem cell-derived tissues. Detailed analysis of adult TECs is technically challenging due to their rarity, their diminishing numbers with age, and the limited number of markers to distinguish between unique TEC subpopulations. Here, we have devised an improved isolation protocol for adult mouse TECs and combined it with six-color multiparameter flow cytometry. Using these techniques, we have identified four distinct subsets of CD45- EpCAM+ TECs in adult mice: a) UEA1(low) CDR1(low) (UC(low)); b) UEA1(high) CDR1(high)(UC(high)); c) UEA1(low) CDR1(high) MHC(high) (cTEC); and d) UEA1(high)CDR1(low) MHC(int/high) (mTEC). PCR analysis verified that these TEC subsets differentially expressed known TEC genes. TEC subsets were further analyzed using high-throughput quantitative PCR arrays to reveal novel genes that could be important for TEC subset maintenance. Intracellular staining for keratin-5 and keratin-8 can also be added, but our results suggest that keratin expression alone cannot be used to distinguish adult TEC subsets. Our enhanced isolation allows for detailed analysis of rare TEC subpopulations in the adult mouse at the cellular and molecular levels.
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Affiliation(s)
- Bryce T McLelland
- School of Natural Sciences, University of California, Merced, 5200 North Lake Road, Merced, CA 95340, USA
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52
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Atibalentja DF, Murphy KM, Unanue ER. Functional redundancy between thymic CD8α+ and Sirpα+ conventional dendritic cells in presentation of blood-derived lysozyme by MHC class II proteins. THE JOURNAL OF IMMUNOLOGY 2010; 186:1421-31. [PMID: 21178002 DOI: 10.4049/jimmunol.1002587] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
We evaluated the presentation of blood-derived protein Ags by APCs in the thymus. Two conventional dendritic cells (cDCs), the CD8α(+)Sirpα(-)CD11c(hi) (CD8α(+) cDC) and the CD8α(-)Sirpα(+)CD11c(hi) (Sirpα(+) cDC), were previously identified as presenting MHC class II bound peptides from hen egg white lysozyme (HEL) injected intravenously. All thymic APCs acquired the injected HEL, with the plasmacytoid dendritic cell being the best, followed by the Sirpα(+) cDC and the CD8α(+) cDC. Both cDCs induced to similar extent negative selection and regulatory T cells in HEL TCR transgenic mice, indicating a redundant role of the two cDC subsets in the presentation of blood-borne HEL. Immature dendritic cells or plasmacytoid dendritic cells were considerably less efficient. Batf3(-/-) mice, with significantly reduced numbers of CD8α(+) cDCs, were not impaired in HEL presentation by I-A(k) molecules of thymic APCs. Lastly, clodronate liposome treatment of TCR transgenic mice depleted blood APCs including Sirpα(+) cDCs without affecting the number of thymic APCs. In such treated mice, there was no effect on negative selection or regulatory T cells in mice when administering HEL, indicating that the T cell responses were mediated primarily by the cDCs localized in the thymus.
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Affiliation(s)
- Danielle F Atibalentja
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA
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Gossens K, Naus S, Holländer GA, Ziltener HJ. Deficiency of the metalloproteinase-disintegrin ADAM8 is associated with thymic hyper-cellularity. PLoS One 2010; 5:e12766. [PMID: 20856819 PMCID: PMC2939894 DOI: 10.1371/journal.pone.0012766] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2010] [Accepted: 08/19/2010] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND Thymopoiesis requires thymocyte-stroma interactions and proteases that promote cell migration by degrading extracellular matrix and releasing essential cytokines and chemokines. A role for several members of the A Disintegrin and Metalloprotease (ADAM) family in T cell development has been reported in the past. METHODOLOGY/PRINCIPAL FINDINGS Here, we present data indicating that the family member ADAM8 plays a role in thymic T cell development. We used qrtPCR on FACS sorted thymic subsets together with immunofluorescence to analyze thymic ADAM8 expression. We found that ADAM8 was expressed in murine thymic stromal cells and at lower levels in thymocytes where its expression increased as cell matured, suggesting involvement of ADAM8 in thymopoiesis. Further flow cytometry analysis revealed that ADAM8 deficient mice showed normal development and expansion of immature thymocyte subsets. There was however an intrathymic accumulation of single positive CD4 and CD8 T cells which was most noticeable in the late mature T cell subsets. Accumulation of single positive T cells coincided with changes in the thymic architecture manifest in a decreased cortex/medulla ratio and an increase in medullary epithelial cells as determined by histology and flow cytometry. The increase in single positive T cells was thymus-intrinsic, independent of progenitor homing to the thymus or thymic exit rate of mature T cells. Chemotaxis assays revealed that ADAM8 deficiency was associated with reduced migration of single positive thymocytes towards CCL21. CONCLUSIONS/SIGNIFICANCE Our results show that ADAM8 is involved in T cell maturation in the medulla and suggest a role for this protease in fine-tuning maturation of thymocytes in the medulla. In contrast to ADAM10 and ADAM17 lack of ADAM8 appears to have a relatively minor impact on T cell development, which was unexpected given that maturation of thymocytes is dependent on proper localization and timing of migration.
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Affiliation(s)
- Klaus Gossens
- The Biomedical Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
- Laboratory of Pediatric Immunology, Department of Biomedicine, University of Basel and The University Children's Hospital (UKBB), Basel, Switzerland
| | - Silvia Naus
- The Biomedical Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
- Laboratory of Pediatric Immunology, Department of Biomedicine, University of Basel and The University Children's Hospital (UKBB), Basel, Switzerland
| | - Georg A. Holländer
- Laboratory of Pediatric Immunology, Department of Biomedicine, University of Basel and The University Children's Hospital (UKBB), Basel, Switzerland
| | - Hermann J. Ziltener
- The Biomedical Research Centre, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, British Columbia, Canada
- * E-mail:
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54
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Williams KM, Mella H, Lucas PJ, Williams JA, Telford W, Gress RE. Single cell analysis of complex thymus stromal cell populations: rapid thymic epithelia preparation characterizes radiation injury. Clin Transl Sci 2010; 2:279-85. [PMID: 19750208 DOI: 10.1111/j.1752-8062.2009.00128.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Thymic epithelial cells (TECs) and dendritic cells are essential for the maintenance of thymopoiesis. Because these stromal elements define the progenitor niche, provide critical survival signals and growth factors, and direct positive and negative selection, detailed study of these populations is necessary to understand important elements for thymic renewal after cytotoxic injury. Study of TEC is currently hindered by lengthy enzymatic separation techniques with decreased viability. We present a new rapid separation technique that yields consistent viable TEC numbers in a quarter of the prior preparation time. Using this new procedure, we identify changes in stroma populations following total body irradiation (TBI). By flow cytometry, we show that TBI significantly depletes UEA+ medullary TEC, while sparing Ly51+ CD45- cells. Further characterization of the Ly51+ subset reveals enrichment of fibroblasts (CD45- Ly51+ MHCII-), while cortical TECs (CD45- Ly51+ MHCII+) were markedly reduced. Dendritic cells (CD11lc+ CD45+) were also decreased following TBI. These data suggest that cytotoxic preparative regimens may impair thymic renewal by reducing critical populations of cortical and medullary TEC, and that such thymic damage can be assessed by this new rapid separation technique, thereby providing a means of assessing optimal conditioning pretransplantfor enhancing thymic-dependent immune reconstitution posttranspiant.
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Affiliation(s)
- Kirsten M Williams
- Experimental Transplantation and Immunology Branch, National Cancer Institute, NIH, Bethesda, Maryland, USA.
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55
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Koh AS, Kingston RE, Benoist C, Mathis D. Global relevance of Aire binding to hypomethylated lysine-4 of histone-3. Proc Natl Acad Sci U S A 2010; 107:13016-21. [PMID: 20615959 PMCID: PMC2919944 DOI: 10.1073/pnas.1004436107] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Aire promotes the ectopic expression of a repertoire of peripheral-tissue antigens (PTAs) in thymic medullary epithelial cells (MECs) to mediate deletional tolerance and thereby prevent autoimmunity. Binding of hypomethylated histone 3 (H3)-tails by Aire's plant homeodomain (PHD) finger is essential for Aire function in cultured cell models, prompting speculation that Aire-PHD:H3-tail interactions underlie targeting of Aire to weakly transcribed loci. To evaluate the role of Aire's PHD finger in MECs on a global scale in vivo, we complemented Aire-deficient mice with a mutant of Aire that inhibits its binding to hypomethylated H3K4 residues. Although the range of Aire-targeted genes was largely unaffected in these mice, the D299A mutation caused a global dampening of Aire's transcriptional impact, resulting in an autoimmune disease similar in profile to that of their Aire-deficient counterparts. To test whether a low H3K4 methylation state is sufficient for Aire targeting, we overexpressed an H3K4-specific demethylase in an Aire-dependent cultured cell system, and determined its capacity to extend Aire's transcriptional footprint. The range and magnitude of Aire-regulated genes was largely unaffected, the only genes additionally induced by Aire in this context being those already accessed for repression. In short, Aire's H3-binding module is necessary for Aire-mediated regulation of gene expression and central tolerance induction, but this influence is unlikely to reflect a targeting mechanism solely based on the recognition of hypomethylated H3K4 residues.
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Affiliation(s)
- Andrew S. Koh
- Department of Pathology, Harvard Medical School, Boston, MA 02115; and
- Department of Molecular Biology, Massachusetts General Hospital and Department of Genetics, Harvard Medical School, Boston, MA 02114
| | - Robert E. Kingston
- Department of Molecular Biology, Massachusetts General Hospital and Department of Genetics, Harvard Medical School, Boston, MA 02114
| | | | - Diane Mathis
- Department of Pathology, Harvard Medical School, Boston, MA 02115; and
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56
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Goldberg GL, Dudakov JA, Reiseger JJ, Seach N, Ueno T, Vlahos K, Hammett MV, Young LF, Heng TSP, Boyd RL, Chidgey AP. Sex steroid ablation enhances immune reconstitution following cytotoxic antineoplastic therapy in young mice. THE JOURNAL OF IMMUNOLOGY 2010; 184:6014-24. [PMID: 20483779 DOI: 10.4049/jimmunol.0802445] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Cytotoxic antineoplastic therapy is used to treat malignant disease but results in long-term immunosuppression in postpubertal and adult individuals, leading to increased incidence and severity of opportunistic infections. We have previously shown that sex steroid ablation (SSA) reverses immunodeficiencies associated with age and hematopoietic stem cell transplantation in both autologous and allogeneic settings. In this study, we have assessed the effects of SSA by surgical castration on T cell recovery of young male mice following cyclophosphamide treatment as a model for the impact of chemotherapy. SSA increased thymic cellularity, involving all of the thymocyte subsets and early T lineage progenitors. It also induced early repair of damage to the thymic stromal microenvironment, which is crucial to the recovery of a fully functional T cell-based immune system. These functional changes in thymic stromal subsets included enhanced production of growth factors and chemokines important for thymopoiesis, which preceded increases in both thymocyte and stromal cellularity. These effects collectively translated to an increase in peripheral and splenic naive T cells. In conclusion, SSA enhances T cell recovery following cyclophosphamide treatment of mice, at the level of the thymocytes and their stromal niches. This provides a new approach to immune reconstitution following antineoplastic therapy.
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Affiliation(s)
- Gabrielle L Goldberg
- Immune Regeneration Laboratory, Monash Immunology and Stem Cell Laboratories, Monash University, Clayton, Australia.
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57
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Unique autoreactive T cells recognize insulin peptides generated within the islets of Langerhans in autoimmune diabetes. Nat Immunol 2010; 11:350-4. [PMID: 20190756 PMCID: PMC3080751 DOI: 10.1038/ni.1850] [Citation(s) in RCA: 141] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2009] [Accepted: 02/04/2010] [Indexed: 11/08/2022]
Abstract
In addition to the genetic framework, there are two other critical requirements for the development of tissue-specific autoimmune disease. First, autoreactive T cells need to escape thymic negative selection. Second, they need to find suitable conditions for autoantigen presentation and activation in the target tissue. We show here that these two conditions are fulfilled in diabetic mice of the nonobese diabetic (NOD) strain. A set of autoreactive CD4(+) T cells specific for an insulin peptide, with the noteworthy feature of not recognizing the insulin protein when processed by antigen-presenting cells (APCs), escaped thymic control, participated in diabetes and caused disease. Moreover, APCs in close contact with beta cells in the islets of Langerhans bore vesicles with the antigenic insulin peptides and activated peptide-specific T cells. Our findings may be relevant for other cases of endocrine autoimmunity.
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58
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Atibalentja DF, Byersdorfer CA, Unanue ER. Thymus-blood protein interactions are highly effective in negative selection and regulatory T cell induction. THE JOURNAL OF IMMUNOLOGY 2010; 183:7909-18. [PMID: 19933868 DOI: 10.4049/jimmunol.0902632] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Using hen egg-white lysozyme, the effect of blood proteins on CD4 thymic cells was examined. A small fraction of i.v. injected hen egg-white lysozyme rapidly entered the thymus into the medulla. There it was captured and presented by dendritic cells (DCs) to thymocytes from two TCR transgenic mice, one directed to a dominant peptide and a second to a poorly displayed peptide, both presented by MHC class II molecules I-A(k). Presentation by DC led to negative selection and induction of regulatory T cells, independent of epithelial cells. Presentation took place at very low levels, less than 100 peptide-MHC complexes per DC. Such low levels could induce negative selection, but even lower levels could induce regulatory T cells. The anatomy of the thymus-blood barrier, the highly efficient presentation by DC, together with the high sensitivity of thymic T cells to peptide-MHC complexes, results in blood protein Ags having a profound effect on thymic T cells.
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Affiliation(s)
- Danielle F Atibalentja
- Department of Pathology and Immunology, Washington University School of Medicine, St Louis, MO 63110, USA
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59
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Short-term inhibition of p53 combined with keratinocyte growth factor improves thymic epithelial cell recovery and enhances T-cell reconstitution after murine bone marrow transplantation. Blood 2009; 115:1088-97. [PMID: 19965631 DOI: 10.1182/blood-2009-05-223198] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Myeloablative conditioning before bone marrow transplantation (BMT) results in thymic epithelial cell (TEC) injury, T-cell immune deficiency, and susceptibility to opportunistic infections. Conditioning regimen-induced TEC damage directly contributes to slow thymopoietic recovery after BMT. Keratinocyte growth factor (KGF) is a TEC mitogen that stimulates proliferation and, when given before conditioning, reduces TEC injury. Some TEC subsets are refractory to KGF and functional T-cell responses are not fully restored in KGF-treated BM transplant recipients. Therefore, we investigated whether the addition of a pharmacologic inhibitor, PFT-beta, to transiently inhibit p53 during radiotherapy could spare TECs from radiation-induced damage in congenic and allogeneic BMTs. Combined before BMT KGF + PFT-beta administration additively restored numbers of cortical and medullary TECs and improved thymic function after BMT, resulting in higher numbers of donor-derived, naive peripheral CD4(+) and CD8(+) T cells. Radiation conditioning caused a loss of T-cell zone fibroblastic reticular cells (FRCs) and CCL21 expression in lymphoid stroma. KGF + PFT-beta treatment restored both FRC and CCL21 expression, findings that correlated with improved T-cell reconstitution and an enhanced immune response against Listeria monocytogenes infection. Thus, transient p53 inhibition combined with KGF represents a novel and potentially translatable approach to promote rapid and durable thymic and peripheral T-cell recovery after BMT.
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60
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Mazzucchelli RI, Warming S, Lawrence SM, Ishii M, Abshari M, Washington AV, Feigenbaum L, Warner AC, Sims DJ, Li WQ, Hixon JA, Gray DHD, Rich BE, Morrow M, Anver MR, Cherry J, Naf D, Sternberg LR, McVicar DW, Farr AG, Germain RN, Rogers K, Jenkins NA, Copeland NG, Durum SK. Visualization and identification of IL-7 producing cells in reporter mice. PLoS One 2009; 4:e7637. [PMID: 19907640 PMCID: PMC2770321 DOI: 10.1371/journal.pone.0007637] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2009] [Accepted: 09/22/2009] [Indexed: 01/06/2023] Open
Abstract
Interleukin-7 (IL-7) is required for lymphocyte development and homeostasis although the actual sites of IL-7 production have never been clearly identified. We produced a bacterial artificial chromosome (BAC) transgenic mouse expressing ECFP in the Il7 locus. The construct lacked a signal peptide and ECFP (enhanced cyan fluorescent protein ) accumulated inside IL-7-producing stromal cells in thoracic thymus, cervical thymus and bone marrow. In thymus, an extensive reticular network of IL-7-containing processes extended from cortical and medullary epithelial cells, closely contacting thymocytes. Central memory CD8 T cells, which require IL-7 and home to bone marrow, physically associated with IL-7-producing cells as we demonstrate by intravital imaging.
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Affiliation(s)
- Renata I. Mazzucchelli
- Laboratory of Molecular Immunoregulation, Cancer and Inflammation Program, Center for Cancer Research, National Cancer Institute, National Institute of Health, Frederick, Maryland, United States of America
| | - Søren Warming
- Mouse Cancer Genetics Program, National Cancer Institute, Frederick, Maryland, United States of America
| | - Scott M. Lawrence
- Laboratory Animal Science Program (LASP), Science Applications International Corporation (SAIC), Cancer Research Center, National Cancer Institute, Frederick, Maryland, United States of America
| | - Masaru Ishii
- Lymphocyte Biology Section, Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Mehrnoosh Abshari
- Laboratory Animal Science Program (LASP), Science Applications International Corporation (SAIC), Cancer Research Center, National Cancer Institute, Frederick, Maryland, United States of America
| | - A. Valance Washington
- Laboratory of Experimental Immunology, Cancer and Inflammation Program, Center for Cancer Research, National Cancer Institute, National Institute of Health, Frederick, Maryland, United States of America
| | - Lionel Feigenbaum
- Laboratory Animal Science Program (LASP), Science Applications International Corporation (SAIC), Cancer Research Center, National Cancer Institute, Frederick, Maryland, United States of America
| | - Andrew C. Warner
- Laboratory Animal Science Program (LASP), Science Applications International Corporation (SAIC), Cancer Research Center, National Cancer Institute, Frederick, Maryland, United States of America
| | - Davis J. Sims
- Laboratory Animal Science Program (LASP), Science Applications International Corporation (SAIC), Cancer Research Center, National Cancer Institute, Frederick, Maryland, United States of America
| | - Wen Qing Li
- Laboratory of Molecular Immunoregulation, Cancer and Inflammation Program, Center for Cancer Research, National Cancer Institute, National Institute of Health, Frederick, Maryland, United States of America
| | - Julie A. Hixon
- Laboratory of Molecular Immunoregulation, Cancer and Inflammation Program, Center for Cancer Research, National Cancer Institute, National Institute of Health, Frederick, Maryland, United States of America
| | - Daniel H. D. Gray
- The Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
| | - Benjamin E. Rich
- Department of Dermatology, Brigham and Women's Hospital, Boston, Massachusetts, United States of America
| | - Matthew Morrow
- Human Retrovirus Section, Vaccine Branch, Center for Cancer Research NCI, Frederick, Maryland, United States of America
| | - Miriam R. Anver
- Laboratory Animal Science Program (LASP), Science Applications International Corporation (SAIC), Cancer Research Center, National Cancer Institute, Frederick, Maryland, United States of America
| | - James Cherry
- Gene Expression Laboratory, SAIC-Frederick, Inc., NCI-Frederick, Frederick, Maryland, United States of America
| | - Dieter Naf
- Laboratory Animal Science Program (LASP), Science Applications International Corporation (SAIC), Cancer Research Center, National Cancer Institute, Frederick, Maryland, United States of America
| | - Lawrence R. Sternberg
- Laboratory Animal Science Program (LASP), Science Applications International Corporation (SAIC), Cancer Research Center, National Cancer Institute, Frederick, Maryland, United States of America
| | - Daniel W. McVicar
- Laboratory of Experimental Immunology, Cancer and Inflammation Program, Center for Cancer Research, National Cancer Institute, National Institute of Health, Frederick, Maryland, United States of America
| | - Andrew G. Farr
- Department of Immunology, University of Washington, Seattle, Washington, United States of America
| | - Ronald N. Germain
- Lymphocyte Biology Section, Laboratory of Immunology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Keith Rogers
- Laboratory Animal Science Program (LASP), Science Applications International Corporation (SAIC), Cancer Research Center, National Cancer Institute, Frederick, Maryland, United States of America
| | - Nancy A. Jenkins
- Mouse Cancer Genetics Program, National Cancer Institute, Frederick, Maryland, United States of America
| | - Neal G. Copeland
- Mouse Cancer Genetics Program, National Cancer Institute, Frederick, Maryland, United States of America
| | - Scott K. Durum
- Laboratory of Molecular Immunoregulation, Cancer and Inflammation Program, Center for Cancer Research, National Cancer Institute, National Institute of Health, Frederick, Maryland, United States of America
- * E-mail:
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61
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Yang H, Youm YH, Dixit VD. Inhibition of thymic adipogenesis by caloric restriction is coupled with reduction in age-related thymic involution. THE JOURNAL OF IMMUNOLOGY 2009; 183:3040-52. [PMID: 19648267 DOI: 10.4049/jimmunol.0900562] [Citation(s) in RCA: 134] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Aging of thymus is characterized by reduction in naive T cell output together with progressive replacement of lymphostromal thymic zones with adipocytes. Determining how calorie restriction (CR), a prolongevity metabolic intervention, regulates thymic aging may allow identification of relevant mechanisms to prevent immunosenescence. Using a mouse model of chronic CR, we found that a reduction in age-related thymic adipogenic mechanism is coupled with maintenance of thymic function. The CR increased cellular density in the thymic cortex and medulla and preserved the epithelial signatures. Interestingly, CR prevented the age-related increase in epithelial-mesenchymal transition (EMT) regulators, FoxC2, and fibroblast-specific protein-1 (FSP-1), together with reduction in lipid-laden thymic fibroblasts. Additionally, CR specifically blocked the age-related elevation of thymic proadipogenic master regulator, peroxisome proliferator activated receptor gamma (PPARgamma), and its upstream activator xanthine-oxidoreductase (XOR). Furthermore, we found that specific inhibition of PPARgamma in thymic stromal cells prevented their adipogenic transformation in an XOR-dependent mechanism. Activation of PPARgamma-driven adipogenesis in OP9-DL1 stromal cells compromised their ability to support T cell development. Conversely, CR-induced reduction in EMT and thymic adipogenesis were coupled with elevated thymic output. Compared with 26-mo-old ad libitum fed mice, the T cells derived from age-matched CR animals displayed greater proliferation and higher IL-2 expression. Furthermore, CR prevented the deterioration of the peripheral TCR repertoire diversity in older animals. Collectively, our findings demonstrate that reducing proadipogenic signaling in thymus via CR may promote thymopoiesis during aging.
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Affiliation(s)
- Hyunwon Yang
- Pennington Biomedical Research Center, Louisiana State University System, Baton Rouge, LA 70808, USA
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62
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Fletcher AL, Lowen TE, Sakkal S, Reiseger JJ, Hammett MV, Seach N, Scott HS, Boyd RL, Chidgey AP. Ablation and regeneration of tolerance-inducing medullary thymic epithelial cells after cyclosporine, cyclophosphamide, and dexamethasone treatment. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2009; 183:823-31. [PMID: 19564346 DOI: 10.4049/jimmunol.0900225] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2023]
Abstract
Immunosuppressive drugs and cytotoxic chemotherapy agents are designed to kill or suppress autoreactive, alloaggressive, or hyperinflammatory T cells, or disseminated malignancies. However, they also cause severe immunological side effects ranging from interrupted thymopoiesis and general immunodeficiency to, paradoxically, autoimmunity. Consistent with the cross-talk between thymocytes and stromal cells, we now show that these common therapeutic agents have major effects on murine thymic epithelial cells (TEC), crucially required to rebuild immunity posttreatment. We show that the immunosuppressant cyclosporine A, which has been linked to a thymus-dependent autoimmune syndrome in some patients, causes extensive loss of autoimmune regulator (Aire(+)) tolerance-inducing MHC class II(high) medullary TEC (mTEC(high)). Post-cyclosporine A, Aire expression was restored within 7 days. Full recovery of the mTEC(high) subset occurred within 10 days and was linked to a decrease in a relatively resistant MHC class II(low) mTEC subset (mTEC(low)), consistent with a previously described precursor-product relationship. Cyclophosphamide and dexamethasone caused more extensive ablation of thymocytes and stromal cells but again severely depleted tolerance-inducing mTEC(high). Together, these data show that Aire(+) mTECs are highly sensitive to damage and that mTEC regeneration follows a conserved pattern regardless of the treatment regimen used.
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Affiliation(s)
- Anne L Fletcher
- Immune Regeneration Laboratory, Monash University, Clayton, Australia
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63
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Gossens K, Naus S, Corbel SY, Lin S, Rossi FMV, Kast J, Ziltener HJ. Thymic progenitor homing and lymphocyte homeostasis are linked via S1P-controlled expression of thymic P-selectin/CCL25. ACTA ACUST UNITED AC 2009; 206:761-78. [PMID: 19289576 PMCID: PMC2715120 DOI: 10.1084/jem.20082502] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Thymic T cell progenitor (TCP) importation is a periodic, gated event that is dependent on the expression of functional P-selectin ligands on TCPs. Occupancy of intrathymic TCP niches is believed to negatively regulate TCP importation, but the nature of this feedback mechanism is not yet resolved. We show that P-selectin and CCL25 are periodically expressed in the thymus and are essential parts of the thymic gate-keeping mechanism. Periodicity of thymic TCP receptivity and the size of the earliest intrathymic TCP pool were dependent on the presence of functional P-selectin ligand on TCPs. Furthermore, we show that the numbers of peripheral blood lymphocytes directly affected thymic P-selectin expression and TCP receptivity. We identified sphingosine-1-phosphate (S1P) as one feedback signal that could mediate influence of the peripheral lymphocyte pool on thymic TCP receptivity. Our findings suggest a model whereby thymic TCP importation is controlled by both early thymic niche occupancy and the peripheral lymphocyte pool via S1P.
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Affiliation(s)
- Klaus Gossens
- The Biomedical Research Centre, University of British Columbia, Vancouver, Canada
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64
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Fletcher AL, Seach N, Reiseger JJ, Lowen TE, Hammett MV, Scott HS, Boyd RL. Reduced thymic Aire expression and abnormal NF-kappa B2 signaling in a model of systemic autoimmunity. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2009; 182:2690-9. [PMID: 19234163 DOI: 10.4049/jimmunol.0801752] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2023]
Abstract
The thymic stromal niche normally directs the production and export of a self-tolerant T cell repertoire. Many models of spontaneous autoimmunity, however, develop thymic architectural abnormalities before disease onset. Although this is suspected to affect central tolerance induction, creating an autoimmune predisposition, in-depth analysis of the microenvironment within these thymi is lacking, such that the mechanisms and likely direct effects on the T cell repertoire are unknown or speculative. Here we show that NZB mice, the first described model for systemic autoimmunity, demonstrate a complex thymic phenotype, including a lack of the autoimmune regulator (Aire), early defects in thymic epithelial cell (TEC) expansion, and evidence for altered NF-kappaB2 signaling. Analysis of medullary TEC revealed a numerical loss of the Aire-expressing MHC class II(high) (mTEC-high) subset as well reduced Aire protein and mRNA per cell. RelB expression was also reduced, while chemokines CCL19 and CCL21 were increased. Unexpectedly, the proportion of cortex and medulla in the NZB mice was normal from 36 wk, despite worsening architectural abnormalities. These data show that the NZB defect is more complex than previously appreciated, segregating into early numerical TEC deficiencies that correct with age, late degeneration of the niche architecture that does not affect TEC number, and a persistent reduction in Aire and RelB expression per cell acquired upon mTEC-high differentiation.
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Affiliation(s)
- Anne L Fletcher
- Immune Regeneration Laboratory, Monash University, Clayton, Victoria, Australia
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Abstract
Although the mechanisms of cross-talk that regulate the hematopoietic and epithelial compartments of the thymus are well established, the interactions of these compartments with the thymic endothelium have been largely ignored. Current understanding of the thymic vasculature is based on studies of adult thymus. We show that the neonatal period represents a unique phase of thymic growth and differentiation, marked by endothelium that is organized as primitive, dense networks of capillaries dependent on vascular endothelial growth factor (VEGF). VEGF dependence in neonates is mediated by significantly higher levels of both VEGF production and endothelial VEGF receptor 2 (VEGF-R2) expression than in the adult thymus. VEGF is expressed locally in the neonatal thymus by immature, CD4(-)CD8(-) "double negative" (DN) thymocytes and thymic epithelium. Relative to adult thymus, the neonatal thymus has greater thymocyte proliferation, and a predominance of immature thymocytes and cortical thymic epithelial cells (cTECs). Inhibition of VEGF signaling during the neonatal period results in rapid loss of the dense capillaries in the thymus and a marked reduction in the number of thymocytes. These data demonstrate that, during the early postnatal period, VEGF mediates cross-talk between the thymocyte and endothelial compartments of the thymus.
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Fiorini E, Ferrero I, Merck E, Favre S, Pierres M, Luther SA, MacDonald HR. Cutting Edge: Thymic Crosstalk Regulates Delta-Like 4 Expression on Cortical Epithelial Cells. THE JOURNAL OF IMMUNOLOGY 2008; 181:8199-203. [DOI: 10.4049/jimmunol.181.12.8199] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Seach N, Ueno T, Fletcher AL, Lowen T, Mattesich M, Engwerda CR, Scott HS, Ware CF, Chidgey AP, Gray DHD, Boyd RL. The lymphotoxin pathway regulates Aire-independent expression of ectopic genes and chemokines in thymic stromal cells. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2008; 180:5384-92. [PMID: 18390720 PMCID: PMC2760078 DOI: 10.4049/jimmunol.180.8.5384] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Medullary thymic epithelial cells (mTEC) play an important and unique role in central tolerance, expressing tissue-restricted Ags (TRA) which delete thymocytes autoreactive to peripheral organs. Since deficiencies in this cell type or activity can lead to devastating autoimmune diseases, it is important to understand the factors which regulate mTEC differentiation and function. Lymphotoxin (LT) ligands and the LTbetaR have been recently shown to be important regulators of mTEC biology; however, the precise role of this pathway in the thymus is not clear. In this study, we have investigated the impact of this signaling pathway in greater detail, focusing not only on mTEC but also on other thymic stromal cell subsets. LTbetaR expression was found in all TEC subsets, but the highest levels were detected in MTS-15(+) thymic fibroblasts. Rather than directing the expression of the autoimmune regulator Aire in mTEC, we found LTbetaR signals were important for TRA expression in a distinct population of mTEC characterized by low levels of MHC class II (mTEC(low)), as well as maintenance of MTS-15(+) fibroblasts. In addition, thymic stromal cell subsets from LT-deficient mice exhibit defects in chemokine production similar to that found in peripheral lymphoid organs of Lta(-/-) and Ltbr(-/-) mice. Thus, we propose a broader role for LTalpha1beta2-LTbetaR signaling in the maintenance of the thymic microenvironments, specifically by regulating TRA and chemokine expression in mTEC(low) for efficient induction of central tolerance.
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Affiliation(s)
- Natalie Seach
- Monash Immunology and Stem Cell Laboratories, Monash University, Clayton, Australia
| | - Tomoo Ueno
- Monash Immunology and Stem Cell Laboratories, Monash University, Clayton, Australia
| | - Anne L. Fletcher
- Monash Immunology and Stem Cell Laboratories, Monash University, Clayton, Australia
| | - Tamara Lowen
- Monash Immunology and Stem Cell Laboratories, Monash University, Clayton, Australia
| | | | | | - Hamish S. Scott
- Division of Molecular Medicine, Walter and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia
| | - Carl F. Ware
- Division of Molecular Immunology, La Jolla Institute for Allergy and Immunology, San Diego, CA 92037
| | - Ann P. Chidgey
- Monash Immunology and Stem Cell Laboratories, Monash University, Clayton, Australia
| | | | - Richard L. Boyd
- Monash Immunology and Stem Cell Laboratories, Monash University, Clayton, Australia
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Keratinocyte growth factor and androgen blockade work in concert to protect against conditioning regimen-induced thymic epithelial damage and enhance T-cell reconstitution after murine bone marrow transplantation. Blood 2008; 111:5734-44. [PMID: 18334670 DOI: 10.1182/blood-2008-01-136531] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Myeloablative conditioning results in thymic epithelial cell (TEC) injury, slow T-cell reconstitution, and a high risk of opportunistic infections. Keratinocyte growth factor (KGF) stimulates TEC proliferation and, when given preconditioning, reduces TEC injury. Thymocytes and TECs express androgen receptors, and exposure to androgen inhibits thymopoiesis. In this study, we have investigated whether TEC stimulation via preconditioning treatment with KGF and leuprolide acetate (Lupron), 2 clinically approved agents, given only before conditioning would circumvent the profound TEC and associated T-cell deficiency seen in allogeneic bone marrow transplant (BMT) recipients. Only combined treatment with KGF plus leuprolide acetate normalized TEC subset numbers and thymic architecture. Thymopoiesis and thymic output were supranormal, leading to the accelerated peripheral reconstitution of naive CD4 and CD8 T cells with a broad Vbeta repertoire and decreased homeostatic T-cell proliferation. Combined therapy facilitated T:B cooperativity and enabled a B-cell humoral response to a CD4 T cell-dependent neoantigen challenge soon after BMT. In vivo antigen-specific CD8 T-cell responses and clearance of a live pathogen was superior with combined versus individual agent therapy. Thus, KGF combined with androgen blockade represents a novel approach to restore thymic function and facilitates the rapid recovery of peripheral T-cell function after allogeneic BMT.
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