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Alvarez F, Liu Z, Bay A, Piccirillo CA. Deciphering the developmental trajectory of tissue-resident Foxp3 + regulatory T cells. Front Immunol 2024; 15:1331846. [PMID: 38605970 PMCID: PMC11007185 DOI: 10.3389/fimmu.2024.1331846] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Accepted: 02/14/2024] [Indexed: 04/13/2024] Open
Abstract
Foxp3+ TREG cells have been at the focus of intense investigation for their recognized roles in preventing autoimmunity, facilitating tissue recuperation following injury, and orchestrating a tolerance to innocuous non-self-antigens. To perform these critical tasks, TREG cells undergo deep epigenetic, transcriptional, and post-transcriptional changes that allow them to adapt to conditions found in tissues both at steady-state and during inflammation. The path leading TREG cells to express these tissue-specialized phenotypes begins during thymic development, and is further driven by epigenetic and transcriptional modifications following TCR engagement and polarizing signals in the periphery. However, this process is highly regulated and requires TREG cells to adopt strategies to avoid losing their regulatory program altogether. Here, we review the origins of tissue-resident TREG cells, from their thymic and peripheral development to the transcriptional regulators involved in their tissue residency program. In addition, we discuss the distinct signalling pathways that engage the inflammatory adaptation of tissue-resident TREG cells, and how they relate to their ability to recognize tissue and pathogen-derived danger signals.
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Affiliation(s)
- Fernando Alvarez
- Department of Microbiology and Immunology, McGill University, Montréal, QC, Canada
- Infectious Diseases and Immunology in Global Health Program, The Research Institute of the McGill University Health Centre (RI-MUHC), Montréal, QC, Canada
- Centre of Excellence in Translational Immunology (CETI), Montréal, QC, Canada
| | - Zhiyang Liu
- Department of Microbiology and Immunology, McGill University, Montréal, QC, Canada
- Infectious Diseases and Immunology in Global Health Program, The Research Institute of the McGill University Health Centre (RI-MUHC), Montréal, QC, Canada
- Centre of Excellence in Translational Immunology (CETI), Montréal, QC, Canada
| | - Alexandre Bay
- Department of Microbiology and Immunology, McGill University, Montréal, QC, Canada
- Infectious Diseases and Immunology in Global Health Program, The Research Institute of the McGill University Health Centre (RI-MUHC), Montréal, QC, Canada
- Centre of Excellence in Translational Immunology (CETI), Montréal, QC, Canada
| | - Ciriaco A. Piccirillo
- Department of Microbiology and Immunology, McGill University, Montréal, QC, Canada
- Infectious Diseases and Immunology in Global Health Program, The Research Institute of the McGill University Health Centre (RI-MUHC), Montréal, QC, Canada
- Centre of Excellence in Translational Immunology (CETI), Montréal, QC, Canada
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Chang J, Bouchard A, Bouklouch Y, Panneton V, Li J, Diamantopoulos N, Mohammaei S, Istomine R, Alvarez F, Piccirillo CA, Suh WK. ICOS-Deficient Regulatory T Cells Can Prevent Spontaneous Autoimmunity but Are Impaired in Controlling Acute Inflammation. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2022; 209:301-309. [PMID: 35760518 DOI: 10.4049/jimmunol.2100897] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Accepted: 05/02/2022] [Indexed: 12/12/2022]
Abstract
ICOS is induced in activated T cells and its main role is to boost differentiation and function of effector T cells. ICOS is also constitutively expressed in a subpopulation of Foxp3+ regulatory T cells under steady-state condition. Studies using ICOS germline knockout mice or ICOS-blocking reagents suggested that ICOS has supportive roles in regulatory T (Treg) cell homeostasis, migration, and function. To avoid any compounding effects that may arise from ICOS-deficient non-Treg cells, we generated a conditional knockout system in which ICOS expression is selectively abrogated in Foxp3-expressing cells (ICOS FC mice). Compared to Foxp3-Cre control mice, ICOS FC mice showed a minor numerical deficit of steady-state Treg cells but did not show any signs of spontaneous autoimmunity, indicating that tissue-protective Treg populations do not heavily rely on ICOS costimulation. However, ICOS FC mice showed more severe inflammation in oxazolone-induced contact hypersensitivity, a model of atopic dermatitis. This correlated with elevated numbers of inflammatory T cells expressing IFN-γ and/or TNF-α in ICOS FC mice compared with the control group. In contrast, elimination of ICOS in all T cell compartments negated the differences, confirming that ICOS has a dual positive role in effector and Treg cells. Single-cell transcriptome analysis suggested that ICOS-deficient Treg cells fail to mature into T-bet+CXCR3+ "Th1-Treg" cells in the draining lymph node. Our results suggest that regimens that preferentially stimulate ICOS pathways in Treg cells might be beneficial for the treatment of Th1-driven inflammation.
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Affiliation(s)
- Jinsam Chang
- Institut de Recherches Cliniques de Montréal, Montreal, QC, Canada.,Molecular Biology Program, University of Montreal, Montreal, Quebec, Canada
| | - Antoine Bouchard
- Institut de Recherches Cliniques de Montréal, Montreal, QC, Canada.,Molecular Biology Program, University of Montreal, Montreal, Quebec, Canada
| | - Yasser Bouklouch
- Institut de Recherches Cliniques de Montréal, Montreal, QC, Canada
| | - Vincent Panneton
- Institut de Recherches Cliniques de Montréal, Montreal, QC, Canada.,Department of Microbiology, Infectiology and Immunology, University of Montreal, Montreal, Quebec, Canada
| | - Joanna Li
- Institut de Recherches Cliniques de Montréal, Montreal, QC, Canada.,Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada; and
| | - Nikoletta Diamantopoulos
- Institut de Recherches Cliniques de Montréal, Montreal, QC, Canada.,Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada; and
| | - Saba Mohammaei
- Institut de Recherches Cliniques de Montréal, Montreal, QC, Canada.,Division of Experimental Medicine, McGill University, Montreal, Quebec, Canada
| | - Roman Istomine
- Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada; and
| | - Fernando Alvarez
- Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada; and
| | - Ciriaco A Piccirillo
- Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada; and
| | - Woong-Kyung Suh
- Institut de Recherches Cliniques de Montréal, Montreal, QC, Canada; .,Molecular Biology Program, University of Montreal, Montreal, Quebec, Canada.,Department of Microbiology, Infectiology and Immunology, University of Montreal, Montreal, Quebec, Canada.,Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada; and.,Division of Experimental Medicine, McGill University, Montreal, Quebec, Canada
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