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Greaves RB, Chen D, Green EA. Thymic B Cells as a New Player in the Type 1 Diabetes Response. Front Immunol 2021; 12:772017. [PMID: 34745148 PMCID: PMC8566354 DOI: 10.3389/fimmu.2021.772017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Accepted: 10/01/2021] [Indexed: 12/27/2022] Open
Abstract
Type 1 diabetes (T1d) results from a sustained autoreactive T and B cell response towards insulin-producing β cells in the islets of Langerhans. The autoreactive nature of the condition has led to many investigations addressing the genetic or cellular changes in primary lymphoid tissues that impairs central tolerance- a key process in the deletion of autoreactive T and B cells during their development. For T cells, these studies have largely focused on medullary thymic epithelial cells (mTECs) critical for the effective negative selection of autoreactive T cells in the thymus. Recently, a new cellular player that impacts positively or negatively on the deletion of autoreactive T cells during their development has come to light, thymic B cells. Normally a small population within the thymus of mouse and man, thymic B cells expand in T1d as well as other autoimmune conditions, reside in thymic ectopic germinal centres and secrete autoantibodies that bind selective mTECs precipitating mTEC death. In this review we will discuss the ontogeny, characteristics and functionality of thymic B cells in healthy and autoimmune settings. Furthermore, we explore how in silico approaches may help decipher the complex cellular interplay of thymic B cells with other cells within the thymic microenvironment leading to new avenues for therapeutic intervention.
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Affiliation(s)
- Richard B Greaves
- Centre for Experimental Medicine and Biomedicine, Hull York Medical School, University of York, York, United Kingdom
| | - Dawei Chen
- Centre for Experimental Medicine and Biomedicine, Hull York Medical School, University of York, York, United Kingdom
| | - E Allison Green
- Centre for Experimental Medicine and Biomedicine, Hull York Medical School, University of York, York, United Kingdom
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2
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Thomson DW, Shahrin NH, Wang PPS, Wadham C, Shanmuganathan N, Scott HS, Dinger ME, Hughes TP, Schreiber AW, Branford S. Aberrant RAG-mediated recombination contributes to multiple structural rearrangements in lymphoid blast crisis of chronic myeloid leukemia. Leukemia 2020; 34:2051-2063. [PMID: 32076119 DOI: 10.1038/s41375-020-0751-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Revised: 01/08/2020] [Accepted: 02/06/2020] [Indexed: 11/10/2022]
Abstract
Blast crisis of chronic myeloid leukemia is associated with poor survival and the accumulation of genomic lesions. Using whole-exome and/or RNA sequencing of patients at chronic phase (CP, n = 49), myeloid blast crisis (MBC, n = 19), and lymphoid blast crisis (LBC, n = 20), we found 25 focal gene deletions and 14 fusions in 24 patients in BC. Deletions predominated in LBC (83% of structural variants). Transcriptional analysis identified the upregulation of genes involved in V(D)J recombination, including RAG1/2 and DNTT in LBC. RAG recombination is a reported mediator of IKZF1 deletion. We investigated the extent of RAG-mediated genomic lesions in BC. Molecular hallmarks of RAG activity; DNTT-mediated nucleotide insertions and a RAG-binding motif at structural variants were exclusively found in patients with high RAG expression. Structural variants in 65% of patients in LBC displayed these hallmarks compared with only 5% in MBC. RAG-mediated events included focal deletion and novel fusion of genes associated with hematologic cancer: IKZF1, RUNX1, CDKN2A/B, and RB1. Importantly, 8/8 patients with elevated DNTT at CP diagnosis progressed to LBC by 12 months, potentially enabling early prediction of LBC. This work confirms the central mutagenic role of RAG in LBC and describes potential clinical utility in CML management.
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Affiliation(s)
- Daniel W Thomson
- Department of Genetics and Molecular Pathology, Centre for Cancer Biology, SA Pathology, Adelaide, SA, Australia
- School of Pharmacy and Medical Science, Division of Health Sciences, University of South Australia, Adelaide, SA, Australia
| | - Nur Hezrin Shahrin
- Department of Genetics and Molecular Pathology, Centre for Cancer Biology, SA Pathology, Adelaide, SA, Australia
- School of Pharmacy and Medical Science, Division of Health Sciences, University of South Australia, Adelaide, SA, Australia
| | - Paul P S Wang
- School of Pharmacy and Medical Science, Division of Health Sciences, University of South Australia, Adelaide, SA, Australia
- Australian Cancer Research Foundation Genomics Facility, Centre for Cancer Biology, SA Pathology, Adelaide, SA, Australia
| | - Carol Wadham
- Department of Genetics and Molecular Pathology, Centre for Cancer Biology, SA Pathology, Adelaide, SA, Australia
- School of Pharmacy and Medical Science, Division of Health Sciences, University of South Australia, Adelaide, SA, Australia
| | - Naranie Shanmuganathan
- Department of Genetics and Molecular Pathology, Centre for Cancer Biology, SA Pathology, Adelaide, SA, Australia
- School of Pharmacy and Medical Science, Division of Health Sciences, University of South Australia, Adelaide, SA, Australia
- School of Medicine, Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, SA, Australia
- South Australian Health and Medical Research Institute, Adelaide, SA, Australia
| | - Hamish S Scott
- Department of Genetics and Molecular Pathology, Centre for Cancer Biology, SA Pathology, Adelaide, SA, Australia
- School of Pharmacy and Medical Science, Division of Health Sciences, University of South Australia, Adelaide, SA, Australia
- Australian Cancer Research Foundation Genomics Facility, Centre for Cancer Biology, SA Pathology, Adelaide, SA, Australia
- School of Medicine, Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, SA, Australia
| | - Marcel E Dinger
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Kensington Campus, Sydney, NSW, Australia
| | - Timothy P Hughes
- School of Medicine, Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, SA, Australia
- South Australian Health and Medical Research Institute, Adelaide, SA, Australia
| | - Andreas W Schreiber
- School of Pharmacy and Medical Science, Division of Health Sciences, University of South Australia, Adelaide, SA, Australia
- Australian Cancer Research Foundation Genomics Facility, Centre for Cancer Biology, SA Pathology, Adelaide, SA, Australia
- School of Biological Sciences, University of Adelaide, Adelaide, SA, Australia
| | - Susan Branford
- Department of Genetics and Molecular Pathology, Centre for Cancer Biology, SA Pathology, Adelaide, SA, Australia.
- School of Pharmacy and Medical Science, Division of Health Sciences, University of South Australia, Adelaide, SA, Australia.
- School of Medicine, Faculty of Health and Medical Sciences, University of Adelaide, Adelaide, SA, Australia.
- School of Biological Sciences, University of Adelaide, Adelaide, SA, Australia.
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3
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Ko A, Watanabe M, Nguyen T, Shi A, Achour A, Zhang B, Sun X, Wang Q, Zhuang Y, Weng NP, Hodes RJ. TCR Repertoires of Thymic Conventional and Regulatory T Cells: Identification and Characterization of Both Unique and Shared TCR Sequences. THE JOURNAL OF IMMUNOLOGY 2020; 204:858-867. [PMID: 31924652 DOI: 10.4049/jimmunol.1901006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 12/10/2019] [Indexed: 11/19/2022]
Abstract
Thymic regulatory T cells (tTreg) are critical in the maintenance of normal T cell immunity and tolerance. The role of TCR in tTreg selection remains incompletely understood. In this study, we assessed TCRα and TCRβ sequences of mouse tTreg and thymic conventional CD4+ T cells (Tconv) by high-throughput sequencing. We identified αβ TCR sequences that were unique to either tTreg or Tconv and found that these were distinct as recognized by machine learning algorithm and by preferentially used amino acid trimers in αβ CDR3 of tTreg. In addition, a proportion of αβ TCR sequences expressed by tTreg were also found in Tconv, and machine learning classified the great majority of these shared αβ TCR sequences as characteristic of Tconv and not tTreg. These findings identify two populations of tTreg, one in which the regulatory T cell fate is associated with unique properties of the TCR and another with TCR properties characteristic of Tconv for which tTreg fate is determined by factors beyond TCR sequence.
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Affiliation(s)
- Annette Ko
- Laboratory of Molecular Biology and Immunology, National Institute on Aging, National Institutes of Health, Bethesda, MD 21224
| | - Masashi Watanabe
- Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892
| | - Thomas Nguyen
- Laboratory of Molecular Biology and Immunology, National Institute on Aging, National Institutes of Health, Bethesda, MD 21224
| | - Alvin Shi
- Department of Systems and Computational Biology, Massachusetts Institute of Technology, Cambridge, MA 02139; and
| | - Achouak Achour
- Laboratory of Molecular Biology and Immunology, National Institute on Aging, National Institutes of Health, Bethesda, MD 21224
| | - Baojun Zhang
- Department of Immunology, Duke University, Durham, NC 27710
| | - Xiaoping Sun
- Laboratory of Molecular Biology and Immunology, National Institute on Aging, National Institutes of Health, Bethesda, MD 21224
| | - Qun Wang
- Department of Immunology, Duke University, Durham, NC 27710
| | - Yuan Zhuang
- Department of Immunology, Duke University, Durham, NC 27710
| | - Nan-Ping Weng
- Laboratory of Molecular Biology and Immunology, National Institute on Aging, National Institutes of Health, Bethesda, MD 21224;
| | - Richard J Hodes
- Experimental Immunology Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892;
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Yu S, Zhou X, Hsiao JJ, Yu D, Saunders TL, Xue HH. Fidelity of a BAC-EGFP transgene in reporting dynamic expression of IL-7Rα in T cells. Transgenic Res 2011; 21:201-15. [PMID: 21533667 DOI: 10.1007/s11248-011-9508-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2010] [Accepted: 03/23/2011] [Indexed: 11/27/2022]
Abstract
Interleukin-7 receptor α chain (IL-7Rα)-derived signals are critical for normal T cell development, mature T cell homeostasis, and longevity of memory T cells. IL-7Rα expression in T cells is dynamically regulated at different developmental and antigen-responding stages. However, the molecular mechanism underlying the dynamic regulation is not completely understood. Here we describe generation of a bacterial artificial chromosome (BAC)-based reporter transgenic mouse strain, which contains 210 kb DNA sequence flanking the Il7r locus. We used in vitro validated EGFP reporter and insulator sequences to facilitate the reporter transgene expression. Consistent with endogenous IL-7Rα expression, the BAC transgene was expressed in mature T cells, a portion of natural killer cells but not in mature B cells. In the thymus, the EGFP reporter and endogenous IL-7Rα showed synchronized silencing in CD4(+)CD8(+) double positive stage, were both upregulated in CD4(+) or CD8(+) single positive thymocytes, and both continued to be co-expressed in naïve T cells in the periphery. Upon encountering antigen, the antigen-specific effector CD8(+) T cells downregulated both endogenous IL-7Rα and the EGFP reporter, which were upregulated in synchrony in antigen-specific memory CD8 T cells. These results indicate that the BAC-EGFP transgene reports endogenous IL-7Rα regulation with high fidelity, and further suggest that the 210 kb sequence flanking the Il7r locus contains sufficient genetic information to regulate its expression changes in T lineage cells. Our approach thus represents a critical initial step towards systematic dissection of the cis regulatory elements controlling dynamic IL-7Rα regulation during T cell development and cellular immune responses.
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Affiliation(s)
- Shuyang Yu
- Department of Microbiology, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
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Chougnet CA, Tripathi P, Lages CS, Raynor J, Sholl A, Fink P, Plas DR, Hildeman DA. A major role for Bim in regulatory T cell homeostasis. THE JOURNAL OF IMMUNOLOGY 2010; 186:156-63. [PMID: 21098226 DOI: 10.4049/jimmunol.1001505] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
We have previously shown that regulatory T cells (Treg) accumulate dramatically in aged animals and negatively impact the ability to control persistent infection. However, the mechanisms underlying the age-dependent accrual of Treg remain unclear. In this study, we show that Treg accumulation with age is progressive and likely not the result of increased thymic output, increased peripheral proliferation, or from enhanced peripheral conversion. Instead, we found that Treg from aged mice are more resistant to apoptosis than Treg from young mice. Although Treg from aged mice had increased expression of functional IL-7Rα, we found that IL-7R signaling was not required for maintenance of Treg in vivo. Notably, aged Treg exhibit decreased expression of the proapoptotic molecule Bim compared with Treg from young mice. Furthermore, in the absence of Bim, Treg accumulate rapidly, accounting for >25% of the CD4(+) T cell compartment by 6 mo of age. Additionally, accumulation of Treg in Bim-deficient mice occurred after the cells left the transitional recent thymic emigrant compartment. Mechanistically, we show that IL-2 drives preferential proliferation and accumulation of Bim(lo) Treg. Collectively, our data suggest that chronic stimulation by IL-2 leads to preferential expansion of Treg having low expression of Bim, which favors their survival and accumulation in aged hosts.
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Affiliation(s)
- Claire A Chougnet
- Division of Molecular Immunology, Department of Pediatrics, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH 45229, USA.
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The role of mechanistic factors in promoting chromosomal translocations found in lymphoid and other cancers. Adv Immunol 2010; 106:93-133. [PMID: 20728025 DOI: 10.1016/s0065-2776(10)06004-9] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Recurrent chromosomal abnormalities, especially chromosomal translocations, are strongly associated with certain subtypes of leukemia, lymphoma and solid tumors. The appearance of particular translocations or associated genomic alterations can be important indicators of disease prognosis, and in some cases, certain translocations may indicate appropriate therapy protocols. To date, most of our knowledge about chromosomal translocations has derived from characterization of the highly selected recurrent translocations found in certain cancers. Until recently, mechanisms that promote or suppress chromosomal translocations, in particular, those responsible for their initiation, have not been addressed. For translocations to occur, two distinct chromosomal loci must be broken, brought together (synapsed) and joined. Here, we discuss recent findings on processes and pathways that influence the initiation of chromosomal translocations, including the generation fo DNA double strand breaks (DSBs) by general factors or in the context of the Lymphocyte-specific V(D)J and IgH class-switch recombination processes. We also discuss the role of spatial proximity of DSBs in the interphase nucleus with respect to how DSBs on different chromosomes are justaposed for joining. In addition, we discuss the DNA DSB response and its role in recognizing and tethering chromosomal DSBs to prevent translocations, as well as potential roles of the classical and alternative DSB end-joining pathways in suppressing or promoting translocations. Finally, we discuss the potential roles of long range regulatory elements, such as the 3'IgH enhancer complex, in promoting the expression of certain translocations that are frequent in lymphomas and, thereby, contributing to their frequent appearance in tumors.
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Shimizu C, Kawamoto H, Yamashita M, Kimura M, Kondou E, Kaneko Y, Okada S, Tokuhisa T, Yokoyama M, Taniguchi M, Katsura Y, Nakayama T. Progression of T cell lineage restriction in the earliest subpopulation of murine adult thymus visualized by the expression of lck proximal promoter activity. Int Immunol 2001; 13:105-17. [PMID: 11133839 DOI: 10.1093/intimm/13.1.105] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The proximal promoter of lck directs gene expression exclusively in T cells. To investigate the developmental regulation of the lck proximal promoter activity and its relationship to T cell lineage commitment, a green fluorescence protein (GFP) transgenic (Tg) mouse in which the GFP expression is under the control of the proximal promoter of lck was created. In the adult GFP-Tg mice, >90% of CD4(+)CD8(+) and CD4(+)CD8(-) thymocytes, and the majority of CD4(-)CD8(+) and CD4(-)CD8(-) [double-negative (DN)] thymocytes were highly positive for GFP. Slightly lower but substantial levels of expression of GFP was also observed in mature splenic T cells. No GFP(+) cells was detected in non-T lineage subsets, including mature and immature B cells, CD5(+) B cells, and NK cells, indicating a preserved tissue specificity of the promoter. The earliest GFP(+) cells detected were found in the CD44(+)CD25(-) DN thymocyte subpopulation. The developmental potential of GFP(-) and GFP(+) cells in the CD44(+)CD25(-) DN fraction was examined using in vitro culture systems. The generation of substantial numbers of alphabeta and gammadelta T cells as well as NK cells was demonstrated from both GFP(-) and GFP(+) cells. However, no development of B cells or dendritic cells was detected from GFP(+) CD44(+)CD25(-) DN thymocytes. These results suggest that the progenitors expressing lck proximal promoter activity in the CD44(+)CD25(-) DN thymocyte subset have lost most of the progenitor potential for the B and dendritic cell lineage. Thus, progression of T cell lineage restriction in the earliest thymic population can be visualized by lck proximal promoter activity, suggesting a potential role of Lck in the T cell lineage commitment.
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MESH Headings
- Animals
- B-Lymphocytes/cytology
- Cell Differentiation/genetics
- Cell Differentiation/immunology
- Cell Lineage/genetics
- Cell Lineage/immunology
- Cells, Cultured
- Dendritic Cells/cytology
- Gene Expression Regulation/immunology
- Green Fluorescent Proteins
- Hyaluronan Receptors/biosynthesis
- Killer Cells, Natural/cytology
- Killer Cells, Natural/metabolism
- Luminescent Proteins/biosynthesis
- Luminescent Proteins/genetics
- Lymphocyte Specific Protein Tyrosine Kinase p56(lck)/biosynthesis
- Lymphocyte Specific Protein Tyrosine Kinase p56(lck)/genetics
- Mice
- Mice, Inbred C57BL
- Mice, Transgenic
- Microscopy, Confocal
- Promoter Regions, Genetic/immunology
- Receptors, Antigen, T-Cell, alpha-beta/biosynthesis
- Receptors, Antigen, T-Cell, gamma-delta/biosynthesis
- Receptors, Interleukin-2/biosynthesis
- Scyphozoa
- Spleen/immunology
- Spleen/metabolism
- T-Lymphocyte Subsets/cytology
- T-Lymphocyte Subsets/enzymology
- T-Lymphocyte Subsets/immunology
- T-Lymphocyte Subsets/metabolism
- Thymus Gland/cytology
- Thymus Gland/enzymology
- Thymus Gland/growth & development
- Thymus Gland/immunology
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Affiliation(s)
- C Shimizu
- CREST (Core Research for Evolution Science and Technology) Project, Japan Science and Technology Corporation (JST), and Department of Molecular Immunology, Graduate School of Medicine, Chiba University, 1-8-1 Inohana Chuo-ku, Chiba 260-8670, Japan
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