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Ovcinnikovs V, Ross EM, Petersone L, Edner NM, Heuts F, Ntavli E, Kogimtzis A, Kennedy A, Wang CJ, Bennett CL, Sansom DM, Walker LSK. CTLA-4-mediated transendocytosis of costimulatory molecules primarily targets migratory dendritic cells. Sci Immunol 2019; 4:eaaw0902. [PMID: 31152091 PMCID: PMC6570622 DOI: 10.1126/sciimmunol.aaw0902] [Citation(s) in RCA: 87] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Accepted: 04/02/2019] [Indexed: 12/12/2022]
Abstract
CTLA-4 is a critical negative regulator of the immune system and a major target for immunotherapy. However, precisely how it functions in vivo to maintain immune homeostasis is not clear. As a highly endocytic molecule, CTLA-4 can capture costimulatory ligands from opposing cells by a process of transendocytosis (TE). By restricting costimulatory ligand expression in this manner, CTLA-4 controls the CD28-dependent activation of T cells. Regulatory T cells (Tregs) constitutively express CTLA-4 at high levels and, in its absence, show defects in TE and suppressive function. Activated conventional T cells (Tconv) are also capable of CTLA-4-dependent TE; however, the relative use of this mechanism by Tregs and Tconv in vivo remains unclear. Here, we set out to characterize both the perpetrators and cellular targets of CTLA-4 TE in vivo. We found that Tregs showed constitutive cell surface recruitment of CTLA-4 ex vivo and performed TE rapidly after TCR stimulation. Tregs outperformed activated Tconv at TE in vivo, and expression of ICOS marked Tregs with this capability. Using TCR transgenic Tregs that recognize a protein expressed in the pancreas, we showed that the presentation of tissue-derived self-antigen could trigger Tregs to capture costimulatory ligands in vivo. Last, we identified migratory dendritic cells (DCs) as the major target for Treg-based CTLA-4-dependent regulation in the steady state. These data support a model in which CTLA-4 expressed on Tregs dynamically regulates the phenotype of DCs trafficking to lymph nodes from peripheral tissues in an antigen-dependent manner.
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Affiliation(s)
- Vitalijs Ovcinnikovs
- Institute of Immunity and Transplantation, University College London Division of Infection and Immunity, Royal Free Campus, NW3 2PF London , UK
| | - Ellen M Ross
- Institute of Immunity and Transplantation, University College London Division of Infection and Immunity, Royal Free Campus, NW3 2PF London , UK
| | - Lina Petersone
- Institute of Immunity and Transplantation, University College London Division of Infection and Immunity, Royal Free Campus, NW3 2PF London , UK
| | - Natalie M Edner
- Institute of Immunity and Transplantation, University College London Division of Infection and Immunity, Royal Free Campus, NW3 2PF London , UK
| | - Frank Heuts
- Institute of Immunity and Transplantation, University College London Division of Infection and Immunity, Royal Free Campus, NW3 2PF London , UK
| | - Elisavet Ntavli
- Institute of Immunity and Transplantation, University College London Division of Infection and Immunity, Royal Free Campus, NW3 2PF London , UK
| | - Alexandros Kogimtzis
- Institute of Immunity and Transplantation, University College London Division of Infection and Immunity, Royal Free Campus, NW3 2PF London , UK
| | - Alan Kennedy
- Institute of Immunity and Transplantation, University College London Division of Infection and Immunity, Royal Free Campus, NW3 2PF London , UK
| | - Chun Jing Wang
- Institute of Immunity and Transplantation, University College London Division of Infection and Immunity, Royal Free Campus, NW3 2PF London , UK
| | - Clare L Bennett
- Institute of Immunity and Transplantation, University College London Division of Infection and Immunity, Royal Free Campus, NW3 2PF London , UK
- Department of Haematology, University College London Cancer Institute, Royal Free Campus, NW3 2PF London, UK
| | - David M Sansom
- Institute of Immunity and Transplantation, University College London Division of Infection and Immunity, Royal Free Campus, NW3 2PF London , UK
| | - Lucy S K Walker
- Institute of Immunity and Transplantation, University College London Division of Infection and Immunity, Royal Free Campus, NW3 2PF London , UK.
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Overall SA, Bourges D, van Driel IR, Gleeson PA. Increased endogenous antigen presentation in the periphery enhances susceptibility to inflammation-induced gastric autoimmunity in mice. Eur J Immunol 2016; 47:155-167. [PMID: 27759162 DOI: 10.1002/eji.201646572] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Revised: 09/06/2016] [Accepted: 10/17/2016] [Indexed: 11/12/2022]
Abstract
How the immune system maintains peripheral tolerance under inflammatory conditions is poorly understood. Here we assessed the fate of gastritogenic T cells following inflammatory activation in vivo. Self-reactive T cells (A23 T cells) specific for the gastric H+ /K+ ATPase α subunit (HKα) were transferred into immunosufficient recipient mice and immunised at a site distant to the stomach with adjuvant containing the cognate HKα peptide antigen. Activation of A23 T cells by immunisation did not impact on either immune tolerance or protection from gastric autoimmunity in wild-type BALB/c mice. However, increased presentation of endogenously derived HKα epitopes by dendritic cells (DCs) in the gastric lymph node of IE-H+ /K+ β transgenic mice (IEβ) reduces A23 T-cell tolerance to gastric antigens after inflammatory activation, with subsequent development of gastritis. While HKα-specific A23 T cells from immunised wild-type mice were poorly responsive to in vitro antigen specific activation, A23 T cells from immunised IEβ transgenic mice were readily re-activated, indicating loss of T-cell anergy. These findings show that DCs of gastric lymph nodes can maintain tolerance of pathogenic T cells following inflammatory stimulation and that the density of endogenous antigen presented to self-reactive T cells is critical in the balance between tolerance and autoimmunity.
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Affiliation(s)
- Sarah A Overall
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, the University of Melbourne, Melbourne, Australia
| | - Dorothée Bourges
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, the University of Melbourne, Melbourne, Australia
| | - Ian R van Driel
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, the University of Melbourne, Melbourne, Australia
| | - Paul A Gleeson
- Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, the University of Melbourne, Melbourne, Australia
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Lim JP, Gosavi P, Mintern JD, Ross EM, Gleeson PA. Sorting nexin 5 selectively regulates dorsal-ruffle-mediated macropinocytosis in primary macrophages. J Cell Sci 2015; 128:4407-19. [PMID: 26459636 DOI: 10.1242/jcs.174359] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Accepted: 10/05/2015] [Indexed: 02/01/2023] Open
Abstract
The regulation of macropinocytosis, a specialised endocytosis pathway, is important for immune cell function. However, it is not known whether the biogenesis of macropinosomes involves one or more distinct pathways. We previously identified sorting nexin 5 (SNX5) as a regulator of macropinocytosis in macrophages. Here, we show that bone-marrow-derived macrophages from SNX5-knockout mice had a 60-70% reduction in macropinocytic uptake of dextran or ovalbumin, whereas phagocytosis and retrograde transport from the plasma membrane to the Golgi was unaffected. In contrast, deficiency of SNX5 had no effect on macropinocytosis or antigen presentation by dendritic cells. Activation of macrophages with CSF-1 resulted in a localisation of SNX5 to actin-rich ruffles in a manner dependent on receptor tyrosine kinases. SNX5-deficient macrophages showed a dramatic reduction in ruffling on the dorsal surface following CSF-1 receptor activation, whereas peripheral ruffling and cell migration were unaffected. We demonstrate that SNX5 is acting upstream of actin polymerisation following CSF-1 receptor activation. Overall, our findings reveal the important contribution of dorsal ruffing to receptor-activated macropinocytosis in primary macrophages and show that SNX5 selectively regulates macropinosomes derived from the dorsal ruffles.
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Affiliation(s)
- Jet Phey Lim
- The Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Prajakta Gosavi
- The Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Justine D Mintern
- The Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Ellen M Ross
- The Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Paul A Gleeson
- The Department of Biochemistry and Molecular Biology and Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, Victoria 3010, Australia
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Price JD, Tarbell KV. The Role of Dendritic Cell Subsets and Innate Immunity in the Pathogenesis of Type 1 Diabetes and Other Autoimmune Diseases. Front Immunol 2015; 6:288. [PMID: 26124756 PMCID: PMC4466467 DOI: 10.3389/fimmu.2015.00288] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Accepted: 05/18/2015] [Indexed: 12/12/2022] Open
Abstract
Dendritic cells (DCs) are key antigen-presenting cells that have an important role in autoimmune pathogenesis. DCs control both steady-state T cell tolerance and activation of pathogenic responses. The balance between these two outcomes depends on several factors, including genetic susceptibility, environmental signals that stimulate varied innate responses, and which DC subset is presenting antigen. Although the specific DC phenotype can diverge depending on the tissue location and context, there are four main subsets identified in both mouse and human: conventional cDC1 and cDC2, plasmacytoid DCs, and monocyte-derived DCs. In this review, we will discuss the role of these subsets in autoimmune pathogenesis and regulation, as well as the genetic and environmental signals that influence their function. Specific topics to be addressed include impact of susceptibility loci on DC subsets, alterations in DC subset development, the role of infection- and host-derived innate inflammatory signals, and the role of the intestinal microbiota on DC phenotype. The effects of these various signals on disease progression and the relative effects of DC subset composition and maturation level of DCs will be examined. These areas will be explored using examples from several autoimmune diseases but will focus mainly on type 1 diabetes.
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Affiliation(s)
- Jeffrey D Price
- Diabetes, Endocrinology, and Obesity Branch, Immune Tolerance Section, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health , Bethesda, MD , USA
| | - Kristin V Tarbell
- Diabetes, Endocrinology, and Obesity Branch, Immune Tolerance Section, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health , Bethesda, MD , USA
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