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Jheng MJ, Kita H. Control of Asthma and Allergy by Regulatory T Cells. Int Arch Allergy Immunol 2024:1-15. [PMID: 39154634 DOI: 10.1159/000540407] [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: 05/20/2024] [Accepted: 07/15/2024] [Indexed: 08/20/2024] Open
Abstract
BACKGROUND Epithelial barriers, such as the lungs and skin, face the challenge of providing the tissues' physiological function and maintaining tolerance to the commensal microbiome and innocuous environmental factors while defending the host against infectious microbes. Asthma and allergic diseases can result from maladaptive immune responses, resulting in exaggerated and persistent type 2 immunity and tissue inflammation. SUMMARY Among the diverse populations of tissue immune cells, CD4+ regulatory T cells (Treg cells) are central to controlling immune responses and inflammation and restoring tissue homeostasis. Humans and mice that are deficient in Treg cells experience extensive inflammation in their mucosal organs and skin. During past decades, major progress has been made toward understanding the immunobiology of Treg cells and the molecular and cellular mechanisms that control their differentiation and function. It is now clear that Treg cells are not a single cell type and that they demonstrate diversity and plasticity depending on their differentiation stages and tissue environment. They could also take on a proinflammatory phenotype in certain conditions. KEY MESSAGES Treg cells perform distinct functions, including the induction of immune tolerance, suppression of inflammation, and promotion of tissue repair. Subsets of Treg cells in mucosal tissues are regulated by their differentiation stage and tissue inflammatory milieu. Treg cell dysfunction likely plays roles in persistent immune responses and tissue inflammation in asthma and allergic diseases.
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Affiliation(s)
- Min-Jhen Jheng
- Mayo Clinic Graduate School of Biomedical Sciences, Mayo Clinic Arizona, Scottsdale, Arizona, USA
| | - Hirohito Kita
- Division of Allergy, Asthma, and Clinical Immunology, Mayo Clinic Arizona, Scottsdale, Arizona, USA
- Department of Immunology, Mayo Clinic Arizona, Scottsdale, Arizona, USA
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Randall TD, Meza-Perez S. Immunity in adipose tissues: Cutting through the fat. Immunol Rev 2024; 324:4-10. [PMID: 38733141 PMCID: PMC11262970 DOI: 10.1111/imr.13344] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/13/2024]
Abstract
Well known functions of adipose tissue include energy storage, regulation of thermogenesis, and glucose homeostasis-each of which are associated with the metabolic functions of fat. However, adipose tissues also have important immune functions. In this issue of Immunological Reviews, we present a series of articles that highlight the immune functions of adipose tissue, including the roles of specialized adipose-resident immune cells and fat-associated lymphoid structures. Importantly, immune cell functions in adipose tissues are often linked to the metabolic functions of adipocytes and vice versa. These reciprocal interactions and how they influence both immune and metabolic functions will be discussed in each article. In the first article, Wang et al.,11 discuss adipose-associated macrophages and how obesity and metabolism impact their phenotype and function. Several articles in this issue discuss T cells as either contributors to, or regulators of, inflammatory responses in adipose tissues. Valentine and Nikolajczyk12 provide insights into the role of T cells in obesity-associated inflammation and their contribution to metabolic dysfunction, whereas an article from Kallies and Vasanthakumar13 and another from Elkins and Li14 describe adipose-associated Tregs and how they help prevent inflammation and maintain metabolic homeostasis. Articles from Okabe35 as well as from Daley and Benezech15 discuss the structure and function of fat-associated lymphoid clusters (FALCs) that are prevalent in some adipose tissues and support local immune responses to pathogens, gut-derived microbes and fat-associated antigens. Finally, an article from Meher and McNamara16 describes how innate-like B1 cells in adipose tissues regulate cardiometabolic disease. Importantly, these articles highlight the physical and functional attributes of adipose tissues that are different between mice and humans, the metabolic and immune differences between various adipose depots in the body and the differences in immune cells, adipose tissues and metabolic functions between the sexes. At the end of this preface, we highlight how these differences are critically important for our understanding of anti-tumor immunity to cancers that metastasize to a specific example of visceral adipose tissue, the omentum. Together, these articles identify some unanswered mechanistic questions that will be important to address for a better understanding of immunity in adipose tissues.
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Affiliation(s)
- Troy D. Randall
- Division of Clinical Immunology and Rheumatology, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Selene Meza-Perez
- Division of Clinical Immunology and Rheumatology, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA
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Kallies A, Vasanthakumar A. Transcriptional and hormonal control of adipose Treg heterogeneity and function. Immunol Rev 2024; 324:42-51. [PMID: 38733158 DOI: 10.1111/imr.13340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/13/2024]
Abstract
Adipose tissue stores excess energy and produces a broad range of factors that regulate multiple physiological processes including systemic energy homeostasis. Visceral adipose tissue (VAT) plays a particularly important role in glucose metabolism as its endocrine function underpins food uptake and energy expenditure. Caloric excess triggers VAT inflammation which can impair insulin sensitivity and cause metabolic deregulation. Regulatory T cells (Tregs) that reside in the VAT suppress inflammation and protect from metabolic disease. The cellular components of VAT and its secretory products play a vital role in fostering the differentiation and maintenance of VAT Tregs. Critically, the physiology and inflammatory tone of VAT exhibit sex-specific disparities, resulting in substantial VAT Treg heterogeneity. Indeed, cytokines and sex hormones promote the differentiation of distinct populations of mature VAT Tregs, each characterized by unique phenotypes, homeostatic requirements, and functions. This review focuses on key findings that have significantly advanced our understanding of VAT Treg biology and the current state of the field, while also discussing open questions that require further exploration.
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Affiliation(s)
- Axel Kallies
- Department of Microbiology and Immunology, University of Melbourne, Melbourne, Victoria, Australia
- Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
| | - Ajithkumar Vasanthakumar
- Department of Microbiology and Immunology, University of Melbourne, Melbourne, Victoria, Australia
- Olivia Newton-John Cancer Research Institute, Heidelberg, Victoria, Australia
- La Trobe University, Bundoora, Victoria, Australia
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Elkins C, Li C. Deciphering visceral adipose tissue regulatory T cells: Key contributors to metabolic health. Immunol Rev 2024; 324:52-67. [PMID: 38666618 PMCID: PMC11262988 DOI: 10.1111/imr.13336] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/23/2024]
Abstract
Regulatory T cells (Tregs) within the visceral adipose tissue (VAT) play a crucial role in controlling tissue inflammation and maintaining metabolic health. VAT Tregs display a unique transcriptional profile and T cell receptor (TCR) repertoire, and closely interact with adipocytes, stromal cells, and other immune components within the local VAT microenvironment. However, in the context of obesity, there is a notable decline in VAT Tregs, resulting in heightened VAT inflammation and insulin resistance. A comprehensive understanding of the biology of VAT Tregs is essential for the development of Treg-based therapies for mitigating obesity-associated metabolic diseases. Recent advancements in lineage tracing tools, genetic mouse models, and various single cell "omics" techniques have significantly progressed our understandings of the origin, differentiation, and regulation of this unique VAT Treg population at steady state and during obesity. The identification of VAT-Treg precursor cells in the secondary lymphoid organs has also provided important insights into the timing, location, and mechanisms through which VAT Tregs acquire their distinctive phenotype that enables them to function within a lipid-rich microenvironment. In this review, we highlight key recent breakthroughs in the VAT-Treg field while discussing pivotal questions that remain unanswered.
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Affiliation(s)
- Cody Elkins
- Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, GA, USA
| | - Chaoran Li
- Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, GA, USA
- Winship Cancer Institute, Emory University School of Medicine, Atlanta, GA, USA
- Department of Dermatology, Emory University School of Medicine, Atlanta, GA, USA
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Wang Q, Hartig SM, Ballantyne CM, Wu H. The multifaceted life of macrophages in white adipose tissue: Immune shift couples with metabolic switch. Immunol Rev 2024; 324:11-24. [PMID: 38683173 PMCID: PMC11262992 DOI: 10.1111/imr.13338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/01/2024]
Abstract
White adipose tissue (WAT) is a vital endocrine organ that regulates energy balance and metabolic homeostasis. In addition to fat cells, WAT harbors macrophages with distinct phenotypes that play crucial roles in immunity and metabolism. Nutrient demands cause macrophages to accumulate in WAT niches, where they remodel the microenvironment and produce beneficial or detrimental effects on systemic metabolism. Given the abundance of macrophages in WAT, this review summarizes the heterogeneity of WAT macrophages in physiological and pathological conditions, including their alterations in quantity, phenotypes, characteristics, and functions during WAT growth and development, as well as healthy or unhealthy expansion. We will discuss the interactions of macrophages with other cell partners in WAT including adipose stem cells, adipocytes, and T cells in the context of various microenvironment niches in lean or obese condition. Finally, we highlight how adipose tissue macrophages merge immunity and metabolic changes to govern energy balance for the organism.
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Affiliation(s)
- Qun Wang
- Key Laboratory of Infection and Immunity of Shandong Province, Department of Immunology, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan 250012, China
| | - Sean M. Hartig
- Department of Medicine, Baylor College of Medicine, Houston, Texas, USA 77030
| | | | - Huaizhu Wu
- Department of Medicine, Baylor College of Medicine, Houston, Texas, USA 77030
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Castro Dopico X, Guryleva M, Mandolesi M, Corcoran M, Coquet JM, Murrell B, Karlsson Hedestam GB. Maintenance of caecal homeostasis by diverse adaptive immune cells in the rhesus macaque. Clin Transl Immunology 2024; 13:e1508. [PMID: 38707998 PMCID: PMC11063928 DOI: 10.1002/cti2.1508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2024] [Revised: 03/04/2024] [Accepted: 04/15/2024] [Indexed: 05/07/2024] Open
Abstract
Objectives The caecum bridges the small and large intestine and plays a front-line role in discriminating gastrointestinal antigens. Although dysregulated in acute and chronic conditions, the tissue is often overlooked immunologically. Methods To address this issue, we applied single-cell transcriptomic-V(D)J sequencing to FACS-isolated CD45+ caecal patch/lamina propria leukocytes from a healthy (5-year-old) female rhesus macaque ex vivo and coupled these data to VDJ deep sequencing reads from haematopoietic tissues. Results We found caecal NK cells and ILC3s to co-exist with a spectrum of effector T cells partially derived from SOX4 + recent thymic emigrants. Tolerogenic Vγ8Vδ1-T cells, plastic CD4+ T helper cells and GZMK + EOMES + and TMIGD2 + tissue-resident memory CD8+ T cells were present and differed metabolically. An IL13 + GATA3 + Th2 subset expressing eicosanoid pathway enzymes was accompanied by IL1RL1 + GATA3 + regulatory T cells and a minor proportion of IgE+ plasma cells (PCs), illustrating tightly regulated type 2 immunity devoid of ILC2s. In terms of B lymphocyte lineages, caecal patch antigen-presenting memory B cells sat alongside germinal centre cells undergoing somatic hypermutation and differentiation into IGF1 + PCs. Prototypic gene expression signatures decreased across PC clusters, and notably, expanded IgA clonotypes could be traced in VDJ deep sequencing reads from additional compartments, including the bone marrow, supporting that these cells contribute a steady stream of systemic antibodies. Conclusions The data advance our understanding of caecal immunological function, revealing processes involved in barrier maintenance and molecular networks relevant to disease.
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Affiliation(s)
- Xaquin Castro Dopico
- Department of Microbiology, Tumor and Cell BiologyKarolinska InstitutetStockholmSweden
| | - Mariia Guryleva
- Department of Microbiology, Tumor and Cell BiologyKarolinska InstitutetStockholmSweden
| | - Marco Mandolesi
- Department of Microbiology, Tumor and Cell BiologyKarolinska InstitutetStockholmSweden
| | - Martin Corcoran
- Department of Microbiology, Tumor and Cell BiologyKarolinska InstitutetStockholmSweden
| | - Jonathan M Coquet
- Department of Microbiology, Tumor and Cell BiologyKarolinska InstitutetStockholmSweden
- Department of Immunology and MicrobiologyUniversity of CopenhagenCopenhagenDKDenmark
| | - Ben Murrell
- Department of Microbiology, Tumor and Cell BiologyKarolinska InstitutetStockholmSweden
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Papatriantafyllou M. A T reg cell duo for VAT control. Nat Rev Immunol 2024; 24:232. [PMID: 38459143 DOI: 10.1038/s41577-024-01018-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/10/2024]
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Grusdat M, Brenner D. Adipose T reg cells in charge of metabolism. Nat Immunol 2024; 25:392-393. [PMID: 38356057 DOI: 10.1038/s41590-024-01762-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2024]
Affiliation(s)
- Melanie Grusdat
- Experimental and Molecular Immunology, Department of Infection and Immunity, Luxembourg Institute of Health, Esch-sur-Alzette, Luxembourg
- Immunology and Genetics, Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Dirk Brenner
- Experimental and Molecular Immunology, Department of Infection and Immunity, Luxembourg Institute of Health, Esch-sur-Alzette, Luxembourg.
- Immunology and Genetics, Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg.
- Odense Research Center for Anaphylaxis, Department of Dermatology and Allergy Center, Odense University Hospital, University of Southern Denmark, Odense, Denmark.
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