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Gebe JA, Gooden MD, Workman G, Nagy N, Bollyky PL, Wight TN, Vernon RB. Modulation of hyaluronan synthases and involvement of T cell-derived hyaluronan in autoimmune responses to transplanted islets. Matrix Biol Plus 2020; 9:100052. [PMID: 33718858 PMCID: PMC7930869 DOI: 10.1016/j.mbplus.2020.100052] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Revised: 11/11/2020] [Accepted: 11/11/2020] [Indexed: 12/22/2022] Open
Abstract
The extracellular matrix glycosaminoglycan hyaluronan (HA) accumulates in human and mouse islets during the onset of autoimmune type 1 diabetes (T1D). HA plays a critical role in T1D pathogenesis, as spontaneous disease is blocked in mice fed the HA synthesis inhibitor 4-methylumbelliferone (4MU). The present study demonstrates the involvement of HA in T cell-mediated autoimmune responses to transplanted islets and in in vivo and in vitro T cell activation. Scaffolded islet implants (SIs) loaded with RIP-mOVA mouse islets expressing chicken ovalbumin (OVA) on their β cells were grafted into T and B cell-deficient RIP-mOVA mice, which subsequently received CD4+ T cells from DO11.10 transgenic mice bearing OVA peptide-specific T cell receptors (TcRs), followed by injection of OVA peptide to induce an immune response to the OVA-expressing islets. By affinity histochemistry (AHC), HA was greatly increased in grafted islets with T cell infiltrates (compared to islets grafted into mice lacking T cells) and a portion of this HA co-localized with the infiltrating T cells. Transferred T cells underwent HA synthase (HAS) isoform switching – T cells isolated from the SI grafts strongly upregulated HAS1 and HAS2 mRNAs and downregulated HAS3 mRNA, in contrast to T cells from graft-draining mesenteric lymph nodes, which expressed HAS3 mRNA only. Expression of HAS1 and HAS2 proteins by T cells in SI infiltrates was confirmed by immunohistochemistry (IHC). DO11.10 mice fed 4MU had suppressed in vivo T cell immune priming (measured as a reduced recall response to OVA peptide) compared to T cells from control mice fed a normal diet. In co-cultures of naïve DO11.10 T cells and OVA peptide-loaded antigen-presenting cells (APCs), pre-exposure of the T cells (but not pre-exposure of APCs) to 4MU inhibited early T cell activation (CD69 expression). In addition, T cells exposed to 4MU during activation in vitro with anti-CD3/CD28 antibodies had inhibited phosphorylation of the CD3ζ subunit of the TcR, a very early event in TcR signaling. Collectively, our results demonstrate that T cell-derived HA plays a significant role in T cell immune responses, and that expression of T cell HAS isoforms changes in a locale-specific manner during in vivo priming and functional phases of the T cell response. T cell infiltration of transplanted islets resulted in increased HA in the islets. Some of the HA in T cell-infiltrated islets was directly associated with T cells. T cells from SIs vs. MLNs differentially expressed mRNA for HAS isoforms 1–3. 4MU suppressed T cell activation and increased the proportion of Tregs in vivo. Exposure of T cells to 4MU inhibited their activation by APCs or mAbs in vitro.
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Affiliation(s)
- John A. Gebe
- Center for Fundamental Immunology, Matrix Biology Program, Benaroya Research Institute at Virginia Mason, Seattle, WA, USA
| | - Michel D. Gooden
- Center for Fundamental Immunology, Matrix Biology Program, Benaroya Research Institute at Virginia Mason, Seattle, WA, USA
| | - Gail Workman
- Center for Fundamental Immunology, Matrix Biology Program, Benaroya Research Institute at Virginia Mason, Seattle, WA, USA
| | - Nadine Nagy
- Division of Infectious Diseases and Geographic Medicine, Department of Medicine, Stanford University School of Medicine, Stanford, CA, USA
| | - Paul L. Bollyky
- Division of Infectious Diseases and Geographic Medicine, Department of Medicine, Stanford University School of Medicine, Stanford, CA, USA
| | - Thomas N. Wight
- Center for Fundamental Immunology, Matrix Biology Program, Benaroya Research Institute at Virginia Mason, Seattle, WA, USA
| | - Robert B. Vernon
- Center for Fundamental Immunology, Matrix Biology Program, Benaroya Research Institute at Virginia Mason, Seattle, WA, USA
- Corresponding author at: Center for Fundamental Immunology, Benaroya Research Institute at Virginia Mason, 1201 Ninth Avenue, Seattle, WA 98101, USA.
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2
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Ohkura N, Sakaguchi S. Transcriptional and epigenetic basis of Treg cell development and function: its genetic anomalies or variations in autoimmune diseases. Cell Res 2020; 30:465-474. [PMID: 32367041 PMCID: PMC7264322 DOI: 10.1038/s41422-020-0324-7] [Citation(s) in RCA: 157] [Impact Index Per Article: 39.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Accepted: 04/08/2020] [Indexed: 01/01/2023] Open
Abstract
Naturally arising regulatory CD4+ T (Treg) cells, which specifically express the transcription factor FoxP3 in the nucleus and CD25 and CTLA-4 on the cell surface, are a T-cell subpopulation specialized for immune suppression, playing a key role in maintaining immunological self-tolerance and homeostasis. FoxP3 is required for Treg function, especially for its suppressive activity. However, FoxP3 expression per se is not necessary for Treg cell lineage commitment in the thymus and insufficient for full Treg-type gene expression in mature Treg cells. It is Treg-specific epigenetic changes such as CpG demethylation and histone modification that can confer a stable and heritable pattern of Treg type gene expression on developing Treg cells in a FoxP3-independent manner. Anomalies in the formation of Treg-specific epigenome, in particular, Treg-specific super-enhancers, which largely include Treg-specific DNA demethylated regions, are indeed able to cause autoimmune diseases in rodents. Furthermore, in humans, single nucleotide polymorphisms in Treg-specific DNA demethylated regions associated with Treg signature genes, such as IL2RA (CD25) and CTLA4, can affect the development and function of naïve Treg cells rather than effector T cells. Such genetic variations are therefore causative of polygenic common autoimmune diseases including type 1 diabetes and rheumatoid arthritis via affecting endogenous natural Treg cells. These findings on the transcription factor network with FoxP3 at a key position as well as Treg-specific epigenetic landscape facilitate our understanding of Treg cell development and function, and can be exploited to prepare functionally stable FoxP3-expressing Treg cells from antigen-specific conventional T cells to treat autoimmune diseases.
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Affiliation(s)
- Naganari Ohkura
- Experimental immunology, Immunology Frontier Research Center, Osaka University, 3-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Shimon Sakaguchi
- Experimental immunology, Immunology Frontier Research Center, Osaka University, 3-1 Yamadaoka, Suita, Osaka, 565-0871, Japan.
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3
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Mechanisms of immunological tolerance. Clin Biochem 2016; 49:324-8. [DOI: 10.1016/j.clinbiochem.2015.05.019] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Revised: 05/11/2015] [Accepted: 05/17/2015] [Indexed: 02/06/2023]
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4
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Thompson LJ, Lai JF, Valladao AC, Thelen TD, Urry ZL, Ziegler SF. Conditioning of naive CD4(+) T cells for enhanced peripheral Foxp3 induction by nonspecific bystander inflammation. Nat Immunol 2016; 17:297-303. [PMID: 26752376 PMCID: PMC4757503 DOI: 10.1038/ni.3329] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2015] [Accepted: 10/21/2015] [Indexed: 12/13/2022]
Abstract
Inflammation induced during infection can both promote and suppress immunity. This contradiction suggests that inflammatory cytokines impact the immune system in a context-dependent manner. Here we show that non-specific bystander inflammation conditioned naïve CD4+ T cells for enhanced peripheral Foxp3 induction and reduced effector differentiation. This resulted in inhibition of immune responses in vivo via Foxp3-dependent effect on antigen-specific naïve CD4+ T cell precursors. Such conditioning may have evolved to allow immunity to infection while limiting subsequent autoimmunity caused by release of self-antigens in the wake of infection. Furthermore, this phenomenon suggests a mechanistic explanation for the concept that early tuning of the immune system by infection impacts the long-term quality of immune regulation.
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Affiliation(s)
- Lucas J Thompson
- Benaroya Research Institute, Immunology Research Program, Seattle, Washington, USA
| | - Jen-Feng Lai
- Benaroya Research Institute, Immunology Research Program, Seattle, Washington, USA
| | - Andrea C Valladao
- Benaroya Research Institute, Immunology Research Program, Seattle, Washington, USA.,Department of Immunology, University of Washington, Seattle, Washington, USA
| | - Tennille D Thelen
- Benaroya Research Institute, Immunology Research Program, Seattle, Washington, USA.,Department of Immunology, University of Washington, Seattle, Washington, USA
| | | | - Steven F Ziegler
- Benaroya Research Institute, Immunology Research Program, Seattle, Washington, USA
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5
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Spontaneous Intestinal Tumorigenesis in Apc (/Min+) Mice Requires Altered T Cell Development with IL-17A. J Immunol Res 2015; 2015:860106. [PMID: 26146642 PMCID: PMC4469837 DOI: 10.1155/2015/860106] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Revised: 05/06/2015] [Accepted: 05/06/2015] [Indexed: 02/07/2023] Open
Abstract
The control of inflammatory diseases requires functional regulatory T cells (Tregs) with significant Gata-3 expression. Here we address the inhibitory role of Tregs on intestinal tumorigenesis in the Apc/Min+ mouse model that resembles human familial adenomatous polyposis (FAP). Apc/Min+ mice had a markedly increased frequency of Foxp3+ Tregs and yet decreased Gata-3 expression in the lamina propria. To address the role of heterozygous Apc gene mutation in Tregs, we generated Foxp3-Cre, Apcflox/+ mice. Tregs from these mice effectively inhibited tumorigenesis comparable to wild type Tregs after adoptive transfer into Apc/Min+ mice, demonstrating that the heterozygous Apc gene mutation in Tregs does not induce the loss of control over tumor microenvironment. Adoptive transfer of in vitro generated Apc/Min+ iTregs (inducible Tregs) failed to inhibit intestinal tumorigenesis, suggesting that naïve CD4 T cells generated from Apc/Min+ mice thymus were impaired. We also showed that adoptively transferred IL-17A-deficient Apc/Min+ Tregs inhibited tumor growth, suggesting that IL-17A was critical to impair the tumor regression function of Apc/Min+ Tregs. Taken together, our results suggest that both T cell development in a functional thymus and IL-17A control the ability of Treg to inhibit intestinal tumorigenesis in Apc/Min+ mice.
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6
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Pfisterer K, Lipnik KM, Hofer E, Elbe-Bürger A. CD90 + Human Dermal Stromal Cells Are Potent Inducers of FoxP3 + Regulatory T Cells. J Invest Dermatol 2015; 135:130-141. [DOI: 10.1038/jid.2014.309] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2013] [Revised: 06/15/2014] [Accepted: 06/30/2014] [Indexed: 01/14/2023]
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7
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Attridge K, Walker LSK. Homeostasis and function of regulatory T cells (Tregs) in vivo: lessons from TCR-transgenic Tregs. Immunol Rev 2014; 259:23-39. [PMID: 24712457 PMCID: PMC4237543 DOI: 10.1111/imr.12165] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The identification of CD25 and subsequently Forkhead box protein 3 (Foxp3) as markers for regulatory T cells (Tregs) has revolutionized our ability to explore this population experimentally. In a similar vein, our understanding of antigen-specific Treg responses in vivo owes much to the fortuitous generation of T-cell receptor (TCR)-transgenic Tregs. This has permitted tracking of Tregs with a defined specificity in vivo, facilitating analysis of how encounter with cognate antigen shapes Treg homeostasis and function. Here, we review the key lessons learned from a decade of analysis of TCR-transgenic Tregs and set this in the broader context of general progress in the field. Use of TCR-transgenic Tregs has led to an appreciation that Tregs are a highly dynamic proliferative population in vivo, rather than an anergic population as they were initially portrayed. It is now clear that Treg homeostasis is positively regulated by encounter with self-antigen expressed on peripheral tissues, which is likely to be relevant to the phenomenon of peripheral repertoire reshaping that has been described for Tregs and the observation that the Treg TCR specificities vary by anatomical location. Substantial evidence has also accumulated to support the role of CD28 costimulation and interleukin-2 in Treg homeostasis. The availability of TCR-transgenic Tregs has enabled analysis of Treg populations that are sufficient or deficient in particular genes, without the comparison being confounded by repertoire alterations. This approach has yielded insights into genes required for Treg function in vivo, with particular progress being made on the role of ctla-4 in this context. As the prospect of manipulating Treg populations in the clinic becomes reality, a full appreciation of the rules governing their homeostasis will prove increasingly important.
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Affiliation(s)
- Kesley Attridge
- Kennedy Institute of Rheumatology, University of Oxford, Oxford, UK
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Kawakami T, Lichtnekert J, Thompson LJ, Karna P, Bouabe H, Hohl TM, Heinecke JW, Ziegler SF, Nelson PJ, Duffield JS. Resident renal mononuclear phagocytes comprise five discrete populations with distinct phenotypes and functions. THE JOURNAL OF IMMUNOLOGY 2013; 191:3358-72. [PMID: 23956422 DOI: 10.4049/jimmunol.1300342] [Citation(s) in RCA: 108] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Recent reports have highlighted greater complexity, plasticity, and functional diversity of mononuclear phagocytes (MPCs), including monocytes, macrophages, and dendritic cells (DCs), in our organs than previously understood. The functions and origins of MPCs resident within healthy organs, especially in the kidney, are less well understood, whereas studies suggest they play roles in disease states distinct from recruited monocytes. We developed an unbiased approach using flow cytometry to analyze MPCs residing in the normal mouse kidney, and identified five discrete subpopulations according to CD11b/CD11c expression as well as F4/80, CD103, CD14, CD16, and CD64 expression. In addition to distinct marker profiles, these subpopulations have different lineages and expression of genes involved in tissue homeostasis, including angiogenesis. Among them, the CD11b(int)CD11c(int) F4/80(high) subpopulation notably exhibited high capacity to produce a representative anti-inflammatory cytokine, IL-10. Each subpopulation had different degrees of both macrophage (phagocytosis) and DC (Ag presentation) capacities, with a tendency to promote differentiation of regulatory T cells, whereas two of these showed expression of transcription factors reported to be highly expressed by classical DCs, and proclivity to exit the kidney following stimulation with LPS. In summary, resident kidney MPCs comprise discrete subpopulations, which cannot be simply classified into the conventional entities, and they produce anti-inflammatory and tissue-homeostatic factors to differing degrees.
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Affiliation(s)
- Takahisa Kawakami
- Division of Nephrology, University of Washington, Seattle, WA 98109, USA.
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9
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Schmitt EG, Williams CB. Generation and function of induced regulatory T cells. Front Immunol 2013; 4:152. [PMID: 23801990 PMCID: PMC3685796 DOI: 10.3389/fimmu.2013.00152] [Citation(s) in RCA: 147] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Accepted: 06/04/2013] [Indexed: 12/17/2022] Open
Abstract
CD4+ CD25+ Foxp3+ regulatory T (Treg) cells are essential to the balance between pro- and anti-inflammatory responses. There are two major subsets of Treg cells, “natural” Treg (nTreg) cells that develop in the thymus, and “induced” Treg (iTreg) cells that arise in the periphery from CD4+ Foxp3− conventional T cells and can be generated in vitro. Previous work has established that both subsets are required for immunological tolerance. Additionally, in vitro-derived iTreg cells can reestablish tolerance in situations where Treg cells are decreased or defective. This review will focus on iTreg cells, drawing comparisons to nTreg cells when possible. We discuss the molecular mechanisms of iTreg cell induction, both in vivo and in vitro, review the Foxp3-dependent and -independent transcriptional landscape of iTreg cells, and examine the proposed suppressive mechanisms utilized by each Treg cell subset. We also compare the T cell receptor repertoire of the Treg cell subsets, discuss inflammatory conditions where iTreg cells are generated or have been used for treatment, and address the issue of iTreg cell stability.
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Affiliation(s)
- Erica G Schmitt
- Section of Rheumatology, Department of Pediatrics, Medical College of Wisconsin , Milwaukee, WI , USA
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10
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McPherson SW, Heuss ND, Gregerson DS. Local "on-demand" generation and function of antigen-specific Foxp3+ regulatory T cells. THE JOURNAL OF IMMUNOLOGY 2013; 190:4971-81. [PMID: 23585681 DOI: 10.4049/jimmunol.1202625] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Extrathymically derived regulatory T cells (iTregs) protect against autoimmunity to tissue-specific Ags. However, whether Ag-specific iTreg generation and function is limited to secondary lymphoid tissue or whether it can occur within the tissue-specific local environment of the cognate Ag remains unresolved. Mice expressing β-galactosidase (βgal) on a retina-specific promoter (βgal mice) in conjunction with mice expressing GFP and diphtheria toxin (DTx) receptor (DTR) under control of the Foxp3 promoter, and βgal-specific TCR transgenic (BG2) mice were used to examine this question. Local depletion (ocular DTx), but not systemic depletion (i.p. DTx), of βgal-specific iTregs enhanced experimental autoimmune uveoretinitis induced by activated βgal-specific effector T cells. Injections of small amounts of βgal into the anterior chamber of the eye produced similar numbers of βgal-specific iTregs in the retina whether the mouse was depleted of pre-existing, circulating Tregs. Taken together, these results suggest that protection from tissue-specific autoimmunity depends on the function of local Ag-specific iTregs and that the retina is capable of local, "on-demand" iTreg generation that is independent of circulating Tregs.
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Affiliation(s)
- Scott W McPherson
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, MN 55455, USA.
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11
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Zhang Q, Cui F, Fang L, Hong J, Zheng B, Zhang JZ. TNF-α impairs differentiation and function of TGF-β-induced Treg cells in autoimmune diseases through Akt and Smad3 signaling pathway. J Mol Cell Biol 2012; 5:85-98. [PMID: 23243069 DOI: 10.1093/jmcb/mjs063] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Deficiency in the TGF-β-induced regulatory T (iTreg) cell differentiation is associated with compromised immune homeostasis and plays a key role in many autoimmune diseases. Therapeutic intervention to enhance in situ iTreg differentiation has become a promising treatment modality for autoimmune diseases. Here we describe that the development of autoimmune inflammation in experimental autoimmune encephalomyelitis (EAE) is associated with selective impairment of iTreg differentiation largely due to the increased production of TNF-α. The neutralization of TNF-α markedly increases iTreg differentiation, leading to the amelioration of EAE, whereas the depletion of iTreg cells abolishes the therapeutic effect of an anti-TNF-α antibody. The inhibition of iTreg differentiation by TNF-α is mediated through a signaling cascade involving the induction of TNF receptor II (TNFR2) expression and the activation of Akt. The activated Akt in turn interacts with Smad3, resulting in the inhibition of TGF-β-induced Smad3 phosphorylation and consequently the reduction of p-Smad3 results in the decreased binding to the specific binding site of the foxp3 promoter, and finally foxp3 transcription itself. Interestingly, this regulatory pathway is iTreg cell specific as TNF-α does not activate Akt in naturally occurring regulatory T cells, therefore conferring a selective effect of TNF-α and its antagonism on iTreg cells. The study sheds new light on the critical role and underlying mechanism of TNF-α in the regulation of iTreg differentiation and provides a novel rationale for TNF-α antagonistic therapy for autoimmune diseases.
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Affiliation(s)
- Qi Zhang
- Institute of Health Sciences, Shanghai Institutes of Biological Sciences, Chinese Academy of Sciences and Shanghai JiaoTong University School of Medicine, Shanghai, China
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12
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Schaue D, Kachikwu EL, McBride WH. Cytokines in radiobiological responses: a review. Radiat Res 2012; 178:505-23. [PMID: 23106210 DOI: 10.1667/rr3031.1] [Citation(s) in RCA: 260] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Cytokines function in many roles that are highly relevant to radiation research. This review focuses on how cytokines are structurally organized, how they are induced by radiation, and how they orchestrate mesenchymal, epithelial and immune cell interactions in irradiated tissues. Pro-inflammatory cytokines are the major components of immediate early gene programs and as such can be rapidly activated after tissue irradiation. They converge with the effects of ionizing radiation in that both generate free radicals including reactive oxygen and nitrogen species (ROS/RNS). "Self" molecules secreted or released from cells after irradiation feed the same paradigm by signaling for ROS and cytokine production. As a result, multilayered feedback control circuits can be generated that perpetuate the radiation tissue damage response. The pro-inflammatory phase persists until such times as perceived challenges to host integrity are eliminated. Antioxidant, anti-inflammatory cytokines then act to restore homeostasis. The balance between pro-inflammatory and anti-inflammatory forces may shift to and fro for a long time after radiation exposure, creating waves as the host tries to deal with persisting pathogenesis. Individual cytokines function within socially interconnected groups to direct these integrated cellular responses. They hunt in packs and form complex cytokine networks that are nested within each other so as to form mutually reinforcing or antagonistic forces. This yin-yang balance appears to have redox as a fulcrum. Because of their social organization, cytokines appear to have a considerable degree of redundancy and it follows that an elevated level of a specific cytokine in a disease situation or after irradiation does not necessarily implicate it causally in pathogenesis. In spite of this, "driver" cytokines are emerging in pathogenic situations that can clearly be targeted for therapeutic benefit, including in radiation settings. Cytokines can greatly affect intrinsic cellular radiosensitivity, the incidence and type of radiation tissue complications, bystander effects, genomic instability and cancer. Minor and not so minor, polymorphisms in cytokine genes give considerable diversity within populations and are relevant to causation of disease. Therapeutic intervention is made difficult by such complexity; but the potential prize is great.
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Affiliation(s)
- Dörthe Schaue
- David Geffen School Medicine, University of California at Los Angeles, Los Angeles, California 90095-1714, USA.
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Wang CJ, Kenefeck R, Wardzinski L, Attridge K, Manzotti C, Schmidt EM, Qureshi OS, Sansom DM, Walker LSK. Cutting edge: cell-extrinsic immune regulation by CTLA-4 expressed on conventional T cells. THE JOURNAL OF IMMUNOLOGY 2012; 189:1118-22. [PMID: 22753931 DOI: 10.4049/jimmunol.1200972] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The CTLA-4 pathway is a key regulator of T cell activation and a critical failsafe against autoimmunity. Although early models postulated that CTLA-4 transduced a negative signal, in vivo evidence suggests that CTLA-4 functions in a cell-extrinsic manner. That multiple cell-intrinsic mechanisms have been attributed to CTLA-4, yet its function in vivo appears to be cell-extrinsic, has been an ongoing paradox in the field. Although CTLA-4 expressed on conventional T cells (Tconv) can mediate inhibitory function, it is unclear why this fails to manifest as an intrinsic effect. In this study, we show that Tconv-expressed CTLA-4 can function in a cell-extrinsic manner in vivo. CTLA-4(+/+) T cells, from DO11/rag(-/-) mice that lack regulatory T cells, were able to regulate the response of CTLA-4(-/-) T cells in cotransfer experiments. This observation provides a potential resolution to the above paradox and suggests CTLA-4 function on both Tconv and regulatory T cells can be achieved through cell-extrinsic mechanisms.
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Affiliation(s)
- Chun Jing Wang
- Medical Research Council Centre for Immune Regulation, University of Birmingham Medical School, Birmingham B15 2TT, United Kingdom
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14
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Bettini ML, Pan F, Bettini M, Finkelstein D, Rehg JE, Floess S, Bell BD, Ziegler SF, Huehn J, Pardoll DM, Vignali DA. Loss of epigenetic modification driven by the Foxp3 transcription factor leads to regulatory T cell insufficiency. Immunity 2012; 36:717-30. [PMID: 22579476 PMCID: PMC3361541 DOI: 10.1016/j.immuni.2012.03.020] [Citation(s) in RCA: 127] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2011] [Revised: 01/19/2012] [Accepted: 03/24/2012] [Indexed: 01/22/2023]
Abstract
Regulatory T (Treg) cells, driven by the Foxp3 transcription factor, are responsible for limiting autoimmunity and chronic inflammation. We showed that a well-characterized Foxp3(gfp) reporter mouse, which expresses an N-terminal GFP-Foxp3 fusion protein, is a hypomorph that causes profoundly accelerated autoimmune diabetes on a NOD background. Although natural Treg cell development and in vitro function are not markedly altered in Foxp3(gfp) NOD and C57BL/6 mice, Treg cell function in inflammatory environments was perturbed and TGF-β-induced Treg cell development was reduced. Foxp3(gfp) was unable to interact with the histone acetyltransferase Tip60, the histone deacetylase HDAC7, and the Ikaros family zinc finger 4, Eos, which led to reduced Foxp3 acetylation and enhanced K48-linked polyubiquitylation. Collectively this results in an altered transcriptional landscape and reduced Foxp3-mediated gene repression, notably at the hallmark IL-2 promoter. Loss of controlled Foxp3-driven epigenetic modification leads to Treg cell insufficiency that enables autoimmunity in susceptible environments.
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Affiliation(s)
- Matthew L. Bettini
- Department of Immunology, St. Jude Children’s Research Hospital, Memphis, TN, 38105, USA
| | - Fan Pan
- Immunology and Hematopoiesis Division, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA
| | - Maria Bettini
- Department of Immunology, St. Jude Children’s Research Hospital, Memphis, TN, 38105, USA
| | - David Finkelstein
- Bioinformatics St. Jude Children’s Research Hospital, Memphis, TN, 38105, USA
| | - Jerold E. Rehg
- Department of Pathology, St. Jude Children’s Research Hospital, Memphis, TN, 38105, USA
| | - Stefan Floess
- Experimental Immunology, Helmholtz Centre for Infection Research, Inhoffenstr. 7, 38124, Braunschweig, Germany
| | | | | | - Jochen Huehn
- Experimental Immunology, Helmholtz Centre for Infection Research, Inhoffenstr. 7, 38124, Braunschweig, Germany
| | - Drew M. Pardoll
- Immunology and Hematopoiesis Division, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA
| | - Dario A.A. Vignali
- Department of Immunology, St. Jude Children’s Research Hospital, Memphis, TN, 38105, USA
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Mukherjee S, Giamberardino C, Thomas JM, Gowdy K, Pastva AM, Wright JR. Surfactant protein A modulates induction of regulatory T cells via TGF-β. THE JOURNAL OF IMMUNOLOGY 2012; 188:4376-84. [PMID: 22474025 DOI: 10.4049/jimmunol.1101775] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
TCR signaling plays a critical role in regulatory T cell (Treg) development. However, the mechanism for tissue-specific induction of Tregs in the periphery remains unclear. We observed that surfactant protein A (SP-A)-deficient mice have impaired expression of Foxp3 and fewer CD25(+)Foxp3(+) Tregs after ex vivo stimulation and after stimulation with LPS in vivo. The addition of exogenous SP-A completely reversed this phenotype. Although SP-A is known to inhibit T cell proliferation under certain activation conditions, both IL-2 levels as well as active TGF-β levels increase on extended culture with exogenous SP-A, providing a key mechanism for the maintenance and induction of Tregs. In addition, kinetic suppression assays demonstrate that SP-A enhances the frequency of functional Foxp3(+) Tregs in responder T cell populations in a TGF-β-dependent manner. In mice treated with LPS in vivo, Tregs increased ∼160% in wild-type mice compared with only a 50% increase in LPS-treated SP-A(-/-) mice 8 d after exposure. Taken together, these findings support the hypothesis that SP-A affects T cell immune function by the induction of Tregs during activation.
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Affiliation(s)
- Sambuddho Mukherjee
- Department of Cell Biology, Duke University Medical Center, Durham NC 27710, USA
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Modulation of tumor tolerance in primary central nervous system malignancies. Clin Dev Immunol 2012; 2012:937253. [PMID: 22312408 PMCID: PMC3270544 DOI: 10.1155/2012/937253] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2011] [Revised: 09/29/2011] [Accepted: 10/03/2011] [Indexed: 12/14/2022]
Abstract
Central nervous system tumors take advantage of the unique immunology of the CNS and develop exquisitely complex stromal networks that promote growth despite the presence of antigen-presenting cells and tumor-infiltrating lymphocytes. It is precisely this immunological paradox that is essential to the survival of the tumor. We review the evidence for functional CNS immune privilege and the impact it has on tumor tolerance. In this paper, we place an emphasis on the role of tumor-infiltrating myeloid cells in maintaining stromal and vascular quiescence, and we underscore the importance of indoleamine 2,3-dioxygenase activity as a myeloid-driven tumor tolerance mechanism. Much remains to be discovered regarding the tolerogenic mechanisms by which CNS tumors avoid immune clearance. Thus, it is an open question whether tumor tolerance in the brain is fundamentally different from that of peripheral sites of tumorigenesis or whether it simply stands as a particularly strong example of such tolerance.
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Dons EM, Raimondi G, Cooper DKC, Thomson AW. Induced regulatory T cells: mechanisms of conversion and suppressive potential. Hum Immunol 2012; 73:328-34. [PMID: 22285847 DOI: 10.1016/j.humimm.2011.12.011] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2011] [Revised: 12/12/2011] [Accepted: 12/15/2011] [Indexed: 01/19/2023]
Abstract
Thymus-derived, naturally occurring CD4(+) Forkhead Box P3(+) regulatory T cells (nTreg) have suppressive activity that is important for the establishment and maintenance of immune homeostasis in the healthy state. Abundant reports have demonstrated that they can suppress pathogenic processes in autoimmune diseases and inhibit transplant rejection and graft-versus-host disease. Far less is known about induced regulatory T cells (iTreg) that are generated from naive T cells in the periphery or in vitro by directing naive T cells to acquire suppressive function under the influence of transforming growth factor-β and other factors. In this review, we describe mechanisms by which naive T cells are thought to be converted into iTreg. We also discuss the suppressive potential of iTreg, particularly in comparison with their naturally occurring counterparts, focusing on those reports in which direct comparisons have been made. Based on current knowledge, we consider the rationale for using iTreg versus nTreg in clinical trials.
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Affiliation(s)
- Eefje M Dons
- Thomas E. Starzl Transplantation Institute, Department of Surgery, University of Pittsburgh, Pittsburgh, PA 15261, USA
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Long SA, Buckner JH. CD4+FOXP3+ T regulatory cells in human autoimmunity: more than a numbers game. THE JOURNAL OF IMMUNOLOGY 2011; 187:2061-6. [PMID: 21856944 DOI: 10.4049/jimmunol.1003224] [Citation(s) in RCA: 217] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Regulatory T cells (Treg) play a dominant role in suppression of autoimmune pathology, as rescue of Treg number and/or function in model systems can both prevent and reverse disease. These findings have generated a series of studies addressing the role of defects in Treg number and function in human autoimmunity. However, demonstrating global defects in Treg of individuals diagnosed with autoimmune diseases has been challenging. These challenges are founded, in part, in the complexity of human autoimmune diseases in which various genetic factors and environmental triggers contribute to disease susceptibility. Moreover, contribution of failed Treg-mediated suppression to pathogenesis can extend to multiple mechanisms. In this article, we discuss what is known with respect to the number and function of CD4(+)FOXP3(+) Treg in human autoimmunity, focusing on representative autoimmunediseases in which there are diverse Treg-mediated defects. We also highlight the need to better understand Treg plasticity and function in the context of autoimmunity.
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Affiliation(s)
- S Alice Long
- Benaroya Research Institute at Virginia Mason, Seattle, WA 98101, USA
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