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Abstract
Obesity is a major risk factor for metabolic disease, with white adipose tissue (WAT) inflammation emerging as a key underlying pathology. Alongside its major role in energy storage, WAT is an important endocrine organ, producing many bioactive molecules, termed adipokines, which not only serve as regulators of systemic metabolism, but also possess immunoregulatory properties. Furthermore, WAT contains a unique immune cell repertoire, including an accumulation of leukocytes that are rare in other locations. These include alternatively activated macrophages, invariant natural killer T cells, and regulatory T cells. Disruption of resident adipose leukocyte homeostasis contributes to obesity-associated inflammation and consequent metabolic disorder. Despite many recent advances in this new field of immuno-metabolism, fundamental questions of why and how inflammation arises as obesity develops are not yet fully understood. Exploring the distinct immune system of adipose tissue is fundamental to our understanding of the endocrine as well as immune systems. In this review, we discuss the roles of adipose tissue leukocytes in the transition to obesity and progression of inflammation and highlight potential anti-inflammatory therapies for combating obesity-related pathology.
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Affiliation(s)
- Mark A Exley
- Department of MedicineBrigham and Women's Hospital, Thorn Bldg, 1405, Harvard Medical School, 75 Francis Street, Boston, Massachusetts 02115, USAFaculty of Medical and Human SciencesManchester Collaborative Centre for Inflammation Research (MCCIR), University of Manchester, 46 Grafton Street, CTF Building Room 2.14b, Manchester M13 9NT, UKDepartment of EndocrinologySt. Vincent's University Hospital, University College Dublin, Dublin, IrelandDepartment of MedicineBrigham and Women's Hospital, Smith Building, Harvard Medical School, One Jimmy Fund Way, Boston, Massachusetts 02115, USA Department of MedicineBrigham and Women's Hospital, Thorn Bldg, 1405, Harvard Medical School, 75 Francis Street, Boston, Massachusetts 02115, USAFaculty of Medical and Human SciencesManchester Collaborative Centre for Inflammation Research (MCCIR), University of Manchester, 46 Grafton Street, CTF Building Room 2.14b, Manchester M13 9NT, UKDepartment of EndocrinologySt. Vincent's University Hospital, University College Dublin, Dublin, IrelandDepartment of MedicineBrigham and Women's Hospital, Smith Building, Harvard Medical School, One Jimmy Fund Way, Boston, Massachusetts 02115, USA
| | - Laura Hand
- Department of MedicineBrigham and Women's Hospital, Thorn Bldg, 1405, Harvard Medical School, 75 Francis Street, Boston, Massachusetts 02115, USAFaculty of Medical and Human SciencesManchester Collaborative Centre for Inflammation Research (MCCIR), University of Manchester, 46 Grafton Street, CTF Building Room 2.14b, Manchester M13 9NT, UKDepartment of EndocrinologySt. Vincent's University Hospital, University College Dublin, Dublin, IrelandDepartment of MedicineBrigham and Women's Hospital, Smith Building, Harvard Medical School, One Jimmy Fund Way, Boston, Massachusetts 02115, USA
| | - Donal O'Shea
- Department of MedicineBrigham and Women's Hospital, Thorn Bldg, 1405, Harvard Medical School, 75 Francis Street, Boston, Massachusetts 02115, USAFaculty of Medical and Human SciencesManchester Collaborative Centre for Inflammation Research (MCCIR), University of Manchester, 46 Grafton Street, CTF Building Room 2.14b, Manchester M13 9NT, UKDepartment of EndocrinologySt. Vincent's University Hospital, University College Dublin, Dublin, IrelandDepartment of MedicineBrigham and Women's Hospital, Smith Building, Harvard Medical School, One Jimmy Fund Way, Boston, Massachusetts 02115, USA
| | - Lydia Lynch
- Department of MedicineBrigham and Women's Hospital, Thorn Bldg, 1405, Harvard Medical School, 75 Francis Street, Boston, Massachusetts 02115, USAFaculty of Medical and Human SciencesManchester Collaborative Centre for Inflammation Research (MCCIR), University of Manchester, 46 Grafton Street, CTF Building Room 2.14b, Manchester M13 9NT, UKDepartment of EndocrinologySt. Vincent's University Hospital, University College Dublin, Dublin, IrelandDepartment of MedicineBrigham and Women's Hospital, Smith Building, Harvard Medical School, One Jimmy Fund Way, Boston, Massachusetts 02115, USA
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52
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von Moltke J, Locksley RM. I-L-C-2 it: type 2 immunity and group 2 innate lymphoid cells in homeostasis. Curr Opin Immunol 2014; 31:58-65. [PMID: 25458996 DOI: 10.1016/j.coi.2014.09.009] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Revised: 09/24/2014] [Accepted: 09/28/2014] [Indexed: 12/17/2022]
Abstract
Innate type 2 immune cells are activated in response to helminths, allergens, and certain types of proteases and particulates. Recently, innate type 2 immune pathways have also been implicated in protective host responses to homeostatic perturbations, such as metabolic dysfunction, atherosclerosis, and tissue injury. In this context, innate type 2 cytokines stimulate local tissues, recruit eosinophils, and alternatively activate macrophages to restore homeostasis. As the major source of innate interleukin (IL)-5 and IL-13, group 2 innate lymphoid cells are positioned to initiate and maintain homeostatic type 2 responses. The absence of exogenous stimuli in these processes implicates endogenous pathways in the activation of type 2 immunity and suggests an alternative evolutionary trajectory for type 2 immunity, apart from its role in response to helminths and allergens.
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Affiliation(s)
- Jakob von Moltke
- Departments of Microbiology and Immunology and Medicine, Howard Hughes Medical Institute, University of California, San Francisco, CA 94143, USA
| | - Richard M Locksley
- Departments of Microbiology and Immunology and Medicine, Howard Hughes Medical Institute, University of California, San Francisco, CA 94143, USA.
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53
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Wolf MJ, Adili A, Piotrowitz K, Abdullah Z, Boege Y, Stemmer K, Ringelhan M, Simonavicius N, Egger M, Wohlleber D, Lorentzen A, Einer C, Schulz S, Clavel T, Protzer U, Thiele C, Zischka H, Moch H, Tschöp M, Tumanov AV, Haller D, Unger K, Karin M, Kopf M, Knolle P, Weber A, Heikenwalder M. Metabolic activation of intrahepatic CD8+ T cells and NKT cells causes nonalcoholic steatohepatitis and liver cancer via cross-talk with hepatocytes. Cancer Cell 2014; 26:549-64. [PMID: 25314080 DOI: 10.1016/j.ccell.2014.09.003] [Citation(s) in RCA: 506] [Impact Index Per Article: 50.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2014] [Revised: 07/28/2014] [Accepted: 09/17/2014] [Indexed: 12/13/2022]
Abstract
Hepatocellular carcinoma (HCC), the fastest rising cancer in the United States and increasing in Europe, often occurs with nonalcoholic steatohepatitis (NASH). Mechanisms underlying NASH and NASH-induced HCC are largely unknown. We developed a mouse model recapitulating key features of human metabolic syndrome, NASH, and HCC by long-term feeding of a choline-deficient high-fat diet. This induced activated intrahepatic CD8(+) T cells, NKT cells, and inflammatory cytokines, similar to NASH patients. CD8(+) T cells and NKT cells but not myeloid cells promote NASH and HCC through interactions with hepatocytes. NKT cells primarily cause steatosis via secreted LIGHT, while CD8(+) and NKT cells cooperatively induce liver damage. Hepatocellular LTβR and canonical NF-κB signaling facilitate NASH-to-HCC transition, demonstrating that distinct molecular mechanisms determine NASH and HCC development.
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Affiliation(s)
- Monika Julia Wolf
- Institute of Surgical Pathology, University Hospital Zurich, Zurich 8091, Switzerland
| | - Arlind Adili
- Institute of Virology, Technische Universität München and Helmholtz Zentrum München, Munich 81675, Germany
| | - Kira Piotrowitz
- LIMES Life and Medical Sciences Institute, University of Bonn, Bonn 53125, Germany
| | - Zeinab Abdullah
- Institutes of Molecular Medicine and Experimental Immunology, University of Bonn, Bonn 53105, Germany
| | - Yannick Boege
- Institute of Surgical Pathology, University Hospital Zurich, Zurich 8091, Switzerland
| | - Kerstin Stemmer
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München & Division of Metabolic Diseases, Technische Universität München, Munich 81657, Germany
| | - Marc Ringelhan
- Institute of Virology, Technische Universität München and Helmholtz Zentrum München, Munich 81675, Germany; Second Medical Department, Klinikum Rechts der Isar, Technische Universität München, Munich 81657, Germany
| | - Nicole Simonavicius
- Institute of Virology, Technische Universität München and Helmholtz Zentrum München, Munich 81675, Germany
| | - Michèle Egger
- Institute of Surgical Pathology, University Hospital Zurich, Zurich 8091, Switzerland
| | - Dirk Wohlleber
- Institute of Molecular Immunology, Technische Universität München, Munich 81675, Germany
| | - Anna Lorentzen
- Institute of Virology, Technische Universität München and Helmholtz Zentrum München, Munich 81675, Germany
| | - Claudia Einer
- Institute of Molecular Toxicology and Pharmacology, Helmholtz Center Munich, German Research Center for Environmental Health, Neuherberg 85764, Germany
| | - Sabine Schulz
- Institute of Molecular Toxicology and Pharmacology, Helmholtz Center Munich, German Research Center for Environmental Health, Neuherberg 85764, Germany
| | - Thomas Clavel
- Junior Group Intestinal Microbiome, Technische Universität München, Freising-Weihenstephan 85350, Germany; Chair of Nutrition and Immunology, ZIEL-Research Center for Nutrition and Food Sciences, Biofunctionality Unit, Technische Universität München, Freising-Weihenstephan 85350, Germany
| | - Ulrike Protzer
- Institute of Virology, Technische Universität München and Helmholtz Zentrum München, Munich 81675, Germany
| | - Christoph Thiele
- LIMES Life and Medical Sciences Institute, University of Bonn, Bonn 53125, Germany
| | - Hans Zischka
- Institute of Molecular Toxicology and Pharmacology, Helmholtz Center Munich, German Research Center for Environmental Health, Neuherberg 85764, Germany
| | - Holger Moch
- Institute of Surgical Pathology, University Hospital Zurich, Zurich 8091, Switzerland
| | - Matthias Tschöp
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München & Division of Metabolic Diseases, Technische Universität München, Munich 81657, Germany
| | | | - Dirk Haller
- Chair of Nutrition and Immunology, ZIEL-Research Center for Nutrition and Food Sciences, Biofunctionality Unit, Technische Universität München, Freising-Weihenstephan 85350, Germany
| | - Kristian Unger
- Research Unit of Radiation Cytogenetics, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg 85764, Germany
| | - Michael Karin
- Laboratory of Gene Regulation and Signal Transduction, Departments of Pharmacology and Pathology, University of California, San Diego, School of Medicine, San Diego, CA 92093, USA
| | - Manfred Kopf
- Molecular Biomedicine, Institute of Molecular Health Sciences, ETH Zurich, Zurich 8093, Switzerland
| | - Percy Knolle
- Institutes of Molecular Medicine and Experimental Immunology, University of Bonn, Bonn 53105, Germany; Institute of Molecular Immunology, Technische Universität München, Munich 81675, Germany
| | - Achim Weber
- Institute of Surgical Pathology, University Hospital Zurich, Zurich 8091, Switzerland.
| | - Mathias Heikenwalder
- Institute of Virology, Technische Universität München and Helmholtz Zentrum München, Munich 81675, Germany.
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Iinuma C, Waki M, Kawakami A, Yamaguchi M, Tomaru U, Sasaki N, Masuda S, Matsui Y, Iwasaki S, Baba T, Kasahara M, Yoshiki T, Paletta D, Herrmann T, Ishizu A. Establishment of a vascular endothelial cell-reactive type II NKT cell clone from a rat model of autoimmune vasculitis. Int Immunol 2014; 27:105-14. [PMID: 25239132 DOI: 10.1093/intimm/dxu088] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We previously generated a rat model that spontaneously developed small vessel vasculitis (SVV). In this study, a T cell clone reactive with rat vascular endothelial cells (REC) was established and named VASC-1. Intravenous injection of VASC-1 induced SVV in normal recipients. VASC-1 was a TCRαβ/CD3-positive CD4/CD8 double-negative T cell clone with expression of NKG2D. The cytokine mRNA profile under unstimulated condition was positive for IL-4 and IFN-γ but negative for IL-2 and IL-10. After interaction with REC, the mRNA expression of IL-2, IL-5 and IL-6 was induced in VASC-1, which was inhibited by blocking of CD1d on the REC surface. Although the protein levels of these cytokines seemed to be lower than the detection limit in the culture medium, IFN-γ was detectable. The production of IFN-γ from the VASC-1 stimulated with LPS-pre-treated REC was inhibited by the CD1d blockade on the REC. These findings indicated VASC-1 as an NKT cell clone. The NKT cell pool includes two major subsets, namely types I and II. Type I NKT cells are characterized by expression of semi-invariant TCRs and the potential to bind to marine sponge-derived α-galactosylceramide (α-GalCer) loaded on CD1d; whereas, type II NKT cells do not manifest these characteristics. VASC-1 exhibited a usage of TCR other than the type I invariant TCR α chain and did not bind to α-GalCer-loaded CD1d; therefore, it was determined as a type II NKT cell clone. The collective evidence suggested that REC-reactive type II NKT cells could be involved in the pathogenesis of SVV in rats.
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Affiliation(s)
- Chihiro Iinuma
- Division of Health Sciences, Graduate School of Health Sciences, Hokkaido University, Sapporo 0600812, Japan
| | - Masashi Waki
- Division of Health Sciences, Graduate School of Health Sciences, Hokkaido University, Sapporo 0600812, Japan
| | - Ai Kawakami
- Division of Health Sciences, Graduate School of Health Sciences, Hokkaido University, Sapporo 0600812, Japan
| | - Madoka Yamaguchi
- Division of Health Sciences, Graduate School of Health Sciences, Hokkaido University, Sapporo 0600812, Japan
| | - Utano Tomaru
- Department of Pathology, Hokkaido University Graduate School of Medicine, Sapporo 0608638, Japan
| | - Naomi Sasaki
- Department of Pathology, Hokkaido University Graduate School of Medicine, Sapporo 0608638, Japan
| | - Sakiko Masuda
- Division of Health Sciences, Graduate School of Health Sciences, Hokkaido University, Sapporo 0600812, Japan
| | - Yuki Matsui
- Division of Health Sciences, Graduate School of Health Sciences, Hokkaido University, Sapporo 0600812, Japan
| | - Sari Iwasaki
- Department of Pathology, Hokkaido University Graduate School of Medicine, Sapporo 0608638, Japan
| | - Tomohisa Baba
- Department of Pathology, Hokkaido University Graduate School of Medicine, Sapporo 0608638, Japan Present address: Division of Molecular Bioregulation, Cancer Research Institute, Kanazawa University, Kanazawa 9201192, Japan
| | - Masanori Kasahara
- Department of Pathology, Hokkaido University Graduate School of Medicine, Sapporo 0608638, Japan
| | - Takashi Yoshiki
- Department of Pathology, Hokkaido University Graduate School of Medicine, Sapporo 0608638, Japan
| | - Daniel Paletta
- Institut für Virologie und Immunbiologie, Julius-Maximilians-Universität Würzburg, Würzburg 97078, Germany
| | - Thomas Herrmann
- Institut für Virologie und Immunbiologie, Julius-Maximilians-Universität Würzburg, Würzburg 97078, Germany
| | - Akihiro Ishizu
- Division of Medical Laboratory Science, Faculty of Health Sciences, Hokkaido University, Sapporo 0600812, Japan
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55
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Abstract
Adipose tissue (AT) lies at the crossroad of nutrition, metabolism, and immunity; AT inflammation was proposed as a central mechanism connecting obesity with its metabolic and vascular complications. Resident immune cells constitute the second largest AT cellular component after adipocytes and as such play important roles in the maintenance of AT homeostasis. Obesity-induced changes in their number and activity result in the activation of local and later systemic inflammatory response, marking the transition from simple adiposity to diseases such as type 2 diabetes mellitus, arterial hypertension, and ischemic heart disease. This review has focused on the various subsets of immune cells in AT and their role in the development of AT inflammation and obesity-induced insulin resistance.
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Affiliation(s)
- Milos Mraz
- Third Department of Medicine - Department of Endocrinology and MetabolismGeneral University Hospital, First Faculty of Medicine of Charles University in Prague, U nemocnice 1, 128 00 Prague 2, Czech Republic
| | - Martin Haluzik
- Third Department of Medicine - Department of Endocrinology and MetabolismGeneral University Hospital, First Faculty of Medicine of Charles University in Prague, U nemocnice 1, 128 00 Prague 2, Czech Republic
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56
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Revelo XS, Luck H, Winer S, Winer DA. Morphological and inflammatory changes in visceral adipose tissue during obesity. Endocr Pathol 2014; 25:93-101. [PMID: 24356782 DOI: 10.1007/s12022-013-9288-1] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Obesity is a major health burden worldwide and is a major factor in the development of insulin resistance and metabolic complications such as type II diabetes. Chronic nutrient excess leads to visceral adipose tissue (VAT) expansion and dysfunction in an active process that involves the adipocytes, their supporting matrix, and immune cell infiltrates. These changes contribute to adipose tissue hypoxia, adipocyte cell stress, and ultimately cell death. Accumulation of lymphocytes, macrophages, and other immune cells around dying adipocytes forms the so-called "crown-like structure", a histological hallmark of VAT in obesity. Cross talk between immune cells in adipose tissue dictates the overall inflammatory response, ultimately leading to the production of pro-inflammatory mediators which directly induce insulin resistance in VAT. In this review, we summarize recent studies demonstrating the dramatic changes that occur in visceral adipose tissue during obesity leading to low-grade chronic inflammation and metabolic disease.
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Affiliation(s)
- Xavier S Revelo
- Division of Cellular & Molecular Biology, Diabetes Research Group, Toronto General Research Institute (TGRI), University Health Network, Toronto, ON, Canada
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57
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Martin-Murphy BV, You Q, Wang H, De La Houssaye BA, Reilly TP, Friedman JE, Ju C. Mice lacking natural killer T cells are more susceptible to metabolic alterations following high fat diet feeding. PLoS One 2014; 9:e80949. [PMID: 24465369 PMCID: PMC3896335 DOI: 10.1371/journal.pone.0080949] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2013] [Accepted: 10/14/2013] [Indexed: 12/12/2022] Open
Abstract
Current estimates suggest that over one-third of the adult population has metabolic syndrome and three-fourths of the obese population has non-alcoholic fatty liver disease (NAFLD). Inflammation in metabolic tissues has emerged as a universal feature of obesity and its co-morbidities, including NAFLD. Natural Killer T (NKT) cells are a subset of innate immune cells that abundantly reside within the liver and are readily activated by lipid antigens. There is general consensus that NKT cells are pivotal regulators of inflammation; however, disagreement exists as to whether NKT cells exert pathogenic or suppressive functions in obesity. Here we demonstrate that CD1d−/− mice, which lack NKT cells, were more susceptible to weight gain and fatty liver following high fat diet (HFD) feeding. Compared with their WT counterparts, CD1d−/− mice displayed increased adiposity and greater induction of inflammatory genes in the liver suggestive of the precursors of NAFLD. Calorimetry studies revealed a significant increase in food intake and trends toward decreased metabolic rate and activity in CD1d−/− mice compared with WT mice. Based on these findings, our results suggest that NKT cells play a regulatory role that helps to prevent diet-induced obesity and metabolic dysfunction and may play an important role in mechanisms governing cross-talk between metabolism and the immune system to regulate energy balance and liver health.
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Affiliation(s)
- Brittany V. Martin-Murphy
- Barbara Davis Center for Diabetes, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
| | - Qiang You
- Department of Biotherapy, Second Affiliated Hospital, Nanjing Medical University, Nanjing, Jiangsu, China
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
| | - Hong Wang
- Division of Endocrinology, Diabetes & Metabolism, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
| | - Becky A. De La Houssaye
- Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
| | - Timothy P. Reilly
- Drug Safety Evaluation, Research & Development, Bristol-Myers Squibb Company, Princeton, New Jersey, United States of America
| | - Jacob E. Friedman
- Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
| | - Cynthia Ju
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
- * E-mail:
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58
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Hams E, Locksley RM, McKenzie AN, Fallon PG. Cutting edge: IL-25 elicits innate lymphoid type 2 and type II NKT cells that regulate obesity in mice. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2013; 191:5349-53. [PMID: 24166975 PMCID: PMC3847854 DOI: 10.4049/jimmunol.1301176] [Citation(s) in RCA: 190] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The cellular composition of visceral adipose tissue (VAT) and release of cytokines by such cells within VAT has been implicated in regulating obesity and metabolic homeostasis. We show the importance of IL-25-responsive innate cells, which release the Th2 cytokine IL-13, in regulating weight and glucose homeostasis in mouse models of diet-induced obesity. Treating obese mice with IL-25 induces weight loss and improves glucose tolerance, and is associated with increased infiltration of innate lymphoid type 2 cells (ILC2), type I and type II NKT cells, eosinophils, and alternatively activated macrophages into the VAT. By depleting ILC2 in obese Rag1(-/-) mice, we observe exacerbated weight gain and glucose intolerance. Conversely, transferring ILC2 or type I or type II NKT cells into obese mice induces transient weight loss and stabilizes glucose homeostasis. Our data identify a mechanism whereby IL-25 eliciting IL-13-producing innate cells regulates inflammation in adipose tissue and prevents diet-induced obesity.
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Affiliation(s)
- Emily Hams
- Trinity Biomedical Sciences Institute, School of Medicine, Trinity College Dublin, Dublin, Ireland
- Institute of Molecular Medicine, St James’s Hospital, Dublin, Ireland
| | - Richard M. Locksley
- Howard Hughes Medical Institute, University of California San Francisco, San Francisco, California, USA
| | | | - Padraic G. Fallon
- Trinity Biomedical Sciences Institute, School of Medicine, Trinity College Dublin, Dublin, Ireland
- Institute of Molecular Medicine, St James’s Hospital, Dublin, Ireland
- National Children’s Research Centre, Our Lady’s Children’s Hospital, Dublin, Ireland
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59
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Rakhshandehroo M, Kalkhoven E, Boes M. Invariant natural killer T cells in adipose tissue: novel regulators of immune-mediated metabolic disease. Cell Mol Life Sci 2013; 70:4711-27. [PMID: 23835837 PMCID: PMC11113180 DOI: 10.1007/s00018-013-1414-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Revised: 06/19/2013] [Accepted: 06/20/2013] [Indexed: 12/14/2022]
Abstract
Adipose tissue (AT) represents a microenvironment where intersection takes place between immune processes and metabolic pathways. A variety of immune cells have been characterized in AT over the past decades, with the most recent addition of invariant natural killer T (iNKT) cells. As members of the T cell family, iNKT cells represent a subset that exhibits both innate and adaptive characteristics and directs ensuing immune responses. In disease conditions, iNKT cells have established roles that include disorders in the autoimmune spectrum in malignancies and infectious diseases. Recent work supports a role for iNKT cells in the maintenance of AT homeostasis through both immune and metabolic pathways. The deficiency of iNKT cells can result in AT metabolic disruptions and insulin resistance. In this review, we summarize recent work on iNKT cells in immune regulation, with an emphasis on AT-resident iNKT cells, and identify the potential mechanisms by which adipocytes can mediate iNKT cell activity.
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Affiliation(s)
- M. Rakhshandehroo
- Section Metabolic Diseases, Department of Molecular Cancer Research, University Medical Center Utrecht, Utrecht, The Netherlands
| | - E. Kalkhoven
- Section Metabolic Diseases, Department of Molecular Cancer Research, University Medical Center Utrecht, Utrecht, The Netherlands
| | - M. Boes
- Department of Pediatric Immunology, Wilhelmina Children’s Hospital, University Medical Center Utrecht, 3584 EA Utrecht, The Netherlands
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60
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Immune cells and metabolic dysfunction. Semin Immunopathol 2013; 36:13-25. [PMID: 24212254 DOI: 10.1007/s00281-013-0403-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Accepted: 10/15/2013] [Indexed: 02/06/2023]
Abstract
Throughout evolution, effective nutrient sensing and control of systemic energy homeostasis have relied on a close physical and functional interaction between immune and metabolically active cells. However, in today's obesogenic environment, this fine-tuned immunometabolic interface is perturbed. As a consequence, chronic inflammatory conditions and aberrant activation of immune cells have emerged as key features of obesity-related metabolic disorders, including insulin resistance, cardiovascular complications, and type 2 diabetes, whereas a major research focus has been placed on the adipocyte-macrophage interaction in the context of metabolic dysfunction; recent studies have not only expanded the scope of relevant immune cells in this setting but also highlight the impact of distinct metabolic organs, including the liver, on immunometabolic control, metabolic disease development, and potential anti-inflammatory therapeutic options in obesity-driven pathologies. This review will thus summarize recent progress in this emerging area of metabolic research.
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61
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Fuentes E, Guzmán-Jofre L, Moore-Carrasco R, Palomo I. Role of PPARs in inflammatory processes associated with metabolic syndrome (Review). Mol Med Rep 2013; 8:1611-6. [PMID: 24100795 DOI: 10.3892/mmr.2013.1714] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2013] [Accepted: 07/24/2013] [Indexed: 12/23/2022] Open
Abstract
Metabolic syndrome (MS) includes the presence of arterial hypertension, insulin resistance, dyslipidemia, cardiovascular disease (CVD) and abdominal obesity, which is associated with a chronic inflammatory response, characterized by abnormal adipokine production, and the activation of certain pro-inflammatory signaling pathways. Furthermore, the changes presented by the adipose tissue in MS favors the secretion of several molecular mediators capable of activating or suppressing a number of transcription factors, such as the peroxisome proliferator-activated receptors (PPARs), whose main functions include storage regulation and fatty acid catabolization. When they are activated by their ligands (synthetic or endogenous), they control several genes involved in intermediate metabolism, which make them, together with the PPAR gamma coactivator-1-α (PGC-1) and the silent information regulator T1 (SIRT1), good targets for treating metabolic diseases and their cardiovascular complications.
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Affiliation(s)
- Eduardo Fuentes
- Department of Clinical Biochemistry and Immunohematology, Faculty of Health Sciences, Interdisciplinary Excellence Research Program on Healthy Aging (PIEI-ES), Universidad de Talca, 3460000 Talca, Chile
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62
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The immune system as a sensor of the metabolic state. Immunity 2013; 38:644-54. [PMID: 23601683 DOI: 10.1016/j.immuni.2013.04.001] [Citation(s) in RCA: 171] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2013] [Accepted: 04/01/2013] [Indexed: 12/20/2022]
Abstract
Mammals possess a remarkable ability to maintain and defend a constant internal milieu against diverse environmental threats. Unsurprisingly, the two systems tasked with these duties, metabolism and immunity, have evolved to share a common modular architecture that allows extensive bidirectional communication and coordination. Indeed, recent observations have highlighted numerous functionally critical immune regulatory modules located within diverse metabolic circuits. In this review, we discuss the architectural commonality between immunity and metabolism and highlight how these two primordially disparate systems leverage shared regulatory axes to coordinate metabolic physiology under conditions of normality and chronic overnutrition. Such an integrated perspective both advances our understanding of basic physiology and highlights potential opportunities for therapeutic intervention in metabolic dysfunction.
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63
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Gao B, Radaeva S. Natural killer and natural killer T cells in liver fibrosis. BIOCHIMICA ET BIOPHYSICA ACTA 2013; 1832:1061-9. [PMID: 23022478 PMCID: PMC3552008 DOI: 10.1016/j.bbadis.2012.09.008] [Citation(s) in RCA: 104] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2012] [Accepted: 09/20/2012] [Indexed: 12/22/2022]
Abstract
The liver lymphocyte population is enriched with natural killer (NK) cells, which play a key role in host defense against viral infection and tumor transformation. Recent evidence from animal models suggests that NK cells also play an important role in inhibiting liver fibrosis by selectively killing early or senescence activated hepatic stellate cells (HSCs) and by producing the anti-fibrotic cytokine IFN-γ. Furthermore, clinical studies have revealed that human NK cells can kill primary human HSCs and that the ability of NK cells from HCV patients to kill HSCs is enhanced and correlates inversely with the stages of liver fibrosis. IFN-α treatment enhances, while other factors (e.g., alcohol, TGF-β) attenuate, the cytotoxicity of NK cells against HSCs, thereby differentially regulating liver fibrogenesis. In addition, the mouse liver lymphocyte population is also enriched for natural killer T (NKT) cells, whereas human liver lymphocytes have a much lower percentage of NKT cells. Many studies suggest that NKT cells promote liver fibrogenesis by producing pro-fibrotic cytokines such as IL-4, IL-13, hedgehog ligands, and osteopontin; however, NKT cells may also attenuate liver fibrosis under certain conditions by killing HSCs and by producing IFN-γ. Finally, the potential for NK and NKT cells to be used as therapeutic targets for anti-fibrotic therapy is discussed. This article is part of a Special Issue entitled: Fibrosis: Translation of basic research to human disease.
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Affiliation(s)
- Bin Gao
- Laboratory of Liver Diseases, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD 20892, USA.
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64
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Fuentes E, Fuentes F, Vilahur G, Badimon L, Palomo I. Mechanisms of chronic state of inflammation as mediators that link obese adipose tissue and metabolic syndrome. Mediators Inflamm 2013. [PMID: 23843680 DOI: 10.1115/2013/136584] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The metabolic syndrome is a cluster of cardiometabolic alterations that include the presence of arterial hypertension, insulin resistance, dyslipidemia, and abdominal obesity. Obesity is associated with a chronic inflammatory response, characterized by abnormal adipokine production, and the activation of proinflammatory signalling pathways resulting in the induction of several biological markers of inflammation. Macrophage and lymphocyte infiltration in adipose tissue may contribute to the pathogenesis of obesity-mediated metabolic disorders. Adiponectin can either act directly on macrophages to shift polarization and/or prime human monocytes into alternative M2-macrophages with anti-inflammatory properties. Meanwhile, the chronic inflammation in adipose tissue is regulated by a series of transcription factors, mainly PPARs and C/EBPs, that in conjunction regulate the expression of hundreds of proteins that participate in the metabolism and storage of lipids and, as such, the secretion by adipocytes. Therefore, the management of the metabolic syndrome requires the development of new therapeutic strategies aimed to alter the main genetic pathways involved in the regulation of adipose tissue metabolism.
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Affiliation(s)
- Eduardo Fuentes
- Immunology and Haematology Laboratory, Department of Clinical Biochemistry and Immunohematology, Faculty of Health Sciences, Interdisciplinary Excellence Research Program on Healthy Aging, Universidad de Talca, Talca, Chile
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65
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Fuentes E, Fuentes F, Vilahur G, Badimon L, Palomo I. Mechanisms of chronic state of inflammation as mediators that link obese adipose tissue and metabolic syndrome. Mediators Inflamm 2013; 2013:136584. [PMID: 23843680 PMCID: PMC3697419 DOI: 10.1155/2013/136584] [Citation(s) in RCA: 126] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2013] [Accepted: 05/31/2013] [Indexed: 12/31/2022] Open
Abstract
The metabolic syndrome is a cluster of cardiometabolic alterations that include the presence of arterial hypertension, insulin resistance, dyslipidemia, and abdominal obesity. Obesity is associated with a chronic inflammatory response, characterized by abnormal adipokine production, and the activation of proinflammatory signalling pathways resulting in the induction of several biological markers of inflammation. Macrophage and lymphocyte infiltration in adipose tissue may contribute to the pathogenesis of obesity-mediated metabolic disorders. Adiponectin can either act directly on macrophages to shift polarization and/or prime human monocytes into alternative M2-macrophages with anti-inflammatory properties. Meanwhile, the chronic inflammation in adipose tissue is regulated by a series of transcription factors, mainly PPARs and C/EBPs, that in conjunction regulate the expression of hundreds of proteins that participate in the metabolism and storage of lipids and, as such, the secretion by adipocytes. Therefore, the management of the metabolic syndrome requires the development of new therapeutic strategies aimed to alter the main genetic pathways involved in the regulation of adipose tissue metabolism.
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Affiliation(s)
- Eduardo Fuentes
- Immunology and Haematology Laboratory, Department of Clinical Biochemistry and Immunohematology, Faculty of Health Sciences, Interdisciplinary Excellence Research Program on Healthy Aging, Universidad de Talca, Talca, Chile
- Centro de Estudios en Alimentos Procesados (CEAP), Conicyt-Regional, Gore Maule, R09I2001 Talca, Chile
| | - Francisco Fuentes
- Interno Sexto Año, Escuela de Medicina, Facultad de Medicina, Universidad Católica del Maule, Chile
| | - Gemma Vilahur
- Centro de Investigación Cardiovascular, ICCC-CSIC, Hospital de la Santa Creu i Sant Pau, CiberOBN, Instituto Carlos III, Barcelona, Spain
| | - Lina Badimon
- Centro de Investigación Cardiovascular, ICCC-CSIC, Hospital de la Santa Creu i Sant Pau, CiberOBN, Instituto Carlos III, Barcelona, Spain
| | - Iván Palomo
- Immunology and Haematology Laboratory, Department of Clinical Biochemistry and Immunohematology, Faculty of Health Sciences, Interdisciplinary Excellence Research Program on Healthy Aging, Universidad de Talca, Talca, Chile
- Centro de Estudios en Alimentos Procesados (CEAP), Conicyt-Regional, Gore Maule, R09I2001 Talca, Chile
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66
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Abstract
Chronic, low-grade inflammation of visceral adipose tissue, and systemically, is a critical link between recent strikingly parallel rises in the incidence of obesity and type 2 diabetes. Macrophages have been recognized for some time to be critical participants in obesity-induced inflammation of adipose tissue. Of late, a score of other cell types of the innate and adaptive arms of the immune system have been suggested to play a positive or negative role in adipose tissue infiltrates. This piece reviews the existing data on these new participants; discusses experimental uncertainties, inconsistencies, and complexities; and puts forward a minimalist synthetic scheme.
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67
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Strodthoff D, Lundberg AM, Agardh HE, Ketelhuth DFJ, Paulsson-Berne G, Arner P, Hansson GK, Gerdes N. Lack of invariant natural killer T cells affects lipid metabolism in adipose tissue of diet-induced obese mice. Arterioscler Thromb Vasc Biol 2013; 33:1189-96. [PMID: 23520162 DOI: 10.1161/atvbaha.112.301105] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
OBJECTIVE Obesity promotes a chronic inflammatory condition in adipose tissue (AT). Impairment of insulin sensitivity coincides with infiltration of T cells into AT in early stages of obesity, when macrophages are not yet present. Here, we examine the role of invariant natural killer T (iNKT) cells, a subtype of T cells activated by lipid antigens, on glucose and lipid metabolism in obesity. APPROACH AND RESULTS Jα18(-/-) mice, specifically lacking iNKT cells, and wild-type mice consumed a chow or high-fat diet for 10 weeks. One third of all T lymphocytes in the liver of wild-type mice were iNKT cells, whereas few were detected in AT. Diet-induced obesity increased blood glucose in both genotypes of mice, whereas glucose tolerance test revealed similar kinetics of glucose clearance in Jα18(-/-) and wild-type mice. Under obese conditions, expression of inflammatory cytokines in AT did not differ between the groups, although the number of T cells and macrophages was lower in Jα18(-/-) mice. Nonetheless, AT homeostasis in Jα18(-/-) mice was altered evidenced by lower AT weight, smaller adipocytes, accelerated lipogenesis, increased expression of hormone-sensitive lipase, and accelerated basal lipolysis. CONCLUSIONS iNKT cells do not affect glucose clearance but rather modulate lipid metabolism in both liver and AT. Only few iNKT cells are found in AT under lean and obese conditions, suggesting that their effects on lipid metabolism are mainly mediated in the liver, their primary host organ.
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Affiliation(s)
- Daniela Strodthoff
- Department of Medicine, Center for Molecular Medicine, Karolinska Institute, Karolinska University Hospital, Stockholm, Sweden
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68
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Johnson AR, Milner JJ, Makowski L. The inflammation highway: metabolism accelerates inflammatory traffic in obesity. Immunol Rev 2013; 249:218-38. [PMID: 22889225 DOI: 10.1111/j.1600-065x.2012.01151.x] [Citation(s) in RCA: 416] [Impact Index Per Article: 37.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
As humans evolved, perhaps the two strongest selection determinants of survival were a robust immune response able to clear bacterial, viral, and parasitic infection and an ability to efficiently store nutrients to survive times when food sources were scarce. These traits are not mutually exclusive. It is now apparent that critical proteins necessary for regulating energy metabolism, such as peroxisome proliferator-activated receptors, Toll-like receptors, and fatty acid-binding proteins, also act as links between nutrient metabolism and inflammatory pathway activation in immune cells. Obesity in humans is a symptom of energy imbalance: the scale has been tipped such that energy intake exceeds energy output and may be a result, in part, of evolutionary selection toward a phenotype characterized by efficient energy storage. As discussed in this review, obesity is a state of low-grade, chronic inflammation that promotes the development of insulin resistance and diabetes. Ironically, the formation of systemic and/or local, tissue-specific insulin resistance upon inflammatory cell activation may actually be a protective mechanism that co-evolved to repartition energy sources within the body during times of stress during infection. However, the point has been reached where a once beneficial adaptive trait has become detrimental to the health of the individual and an immense public health and economic burden. This article reviews the complex relationship between obesity, insulin resistance/diabetes, and inflammation, and although the liver, brain, pancreas, muscle, and other tissues are relevant, we focus specifically on how the obese adipose microenvironment can promote immune cell influx and sustain damaging inflammation that can lead to the onset of insulin resistance and diabetes. Finally, we address how substrate metabolism may regulate the immune response and discuss how fuel uptake and metabolism may be a targetable approach to limit or abrogate obesity-induced inflammation.
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Affiliation(s)
- Amy R Johnson
- Department of Nutrition, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
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69
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Shu CJ, Benoist C, Mathis D. The immune system's involvement in obesity-driven type 2 diabetes. Semin Immunol 2013; 24:436-42. [PMID: 23333525 DOI: 10.1016/j.smim.2012.12.001] [Citation(s) in RCA: 123] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2012] [Accepted: 12/09/2012] [Indexed: 02/06/2023]
Abstract
Type 2 diabetes is now a worldwide epidemic, strongly correlated with an elevated incidence of obesity. Obesity-associated adipose tissue inflammation is a major cause of the decreased insulin sensitivity seen in type 2 diabetes. Recent studies have shed light on the cross-talk between the immune system and organismal metabolism. This review discusses the connection between inflammation in adipose tissue and systemic insulin resistance, focusing on the roles of innate and adaptive immune cell subsets in the pathogenesis of this metabolic disease.
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Affiliation(s)
- Chengyi Jenny Shu
- Division of Immunology, Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA 02115, United States
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70
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Wu L, Van Kaer L. Contribution of lipid-reactive natural killer T cells to obesity-associated inflammation and insulin resistance. Adipocyte 2013; 2:12-16. [PMID: 23700548 PMCID: PMC3661135 DOI: 10.4161/adip.22296] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Obesity is associated with a low-grade, chronic inflammation that promotes the development of a variety of diseases, most notably type 2 diabetes. A number of cell types of the innate and adaptive immune systems have been implicated in this process. Recent studies have focused on the role of natural killer T (NKT) cells, a subset of T lymphocytes that react with lipids, in the development of obesity-associated diseases. These studies have shown that invariant NKT (iNKT) cells, a population of NKT cells expressing a semi-invariant T cell receptor, become rapidly activated in response to lipid excess, and that these cells influence the capacity of other leukocytes to produce cytokines during the progression of obesity. The role of NKT cells in obesity-associated inflammation and insulin resistance has been investigated using NKT cell-deficient animals, adoptive transfer of NKT cells and an iNKT cell agonist. While divergent results have been obtained, it is now clear that NKT cells can modulate the inflammatory milieu in obesity, suggesting that these cells could be targeted for therapeutic intervention in obesity-associated diseases.
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71
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Conklin DJ. From lung to liver: how does airborne particulate matter trigger NASH and systemic insulin resistance? J Hepatol 2013; 58:8-10. [PMID: 23069475 PMCID: PMC4410272 DOI: 10.1016/j.jhep.2012.10.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2012] [Revised: 10/04/2012] [Accepted: 10/08/2012] [Indexed: 12/04/2022]
Affiliation(s)
- Daniel J. Conklin
- Diabetes and Obesity Center, 404E, Delia Baxter Building, 580 South
Preston Street, University of Louisville, Louisville, KY 40292, United
States
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72
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A novel function of adipocytes in lipid antigen presentation to iNKT cells. Mol Cell Biol 2012; 33:328-39. [PMID: 23149942 DOI: 10.1128/mcb.00552-12] [Citation(s) in RCA: 99] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Systemic low-grade chronic inflammation has been intensively investigated in obese subjects. Recently, various immune cell types, such as macrophages, granulocytes, helper T cells, cytotoxic T cells, and B cells, have been implicated in the pathogenesis of adipose tissue inflammation. However, the roles of invariant natural killer T cells (iNKT cells) and the regulation of iNKT cell activity in adipose tissue are not thoroughly understood. Here, we demonstrated that iNKT cells were decreased in number in the adipose tissue of obese subjects. Interestingly, CD1d, a molecule involved in lipid antigen presentation to iNKT cells, was highly expressed in adipocytes, and CD1d-expressing adipocytes stimulated iNKT cell activity through physical interaction. iNKT cell population and CD1d expression were reduced in the adipose tissue of obese mice and humans compared to those of lean subjects. Moreover, iNKT cell-deficient Jα18 knockout mice became more obese and exhibited increased adipose tissue inflammation at the early stage of obesity. These data suggest that adipocytes regulate iNKT cell activity via CD1d and that the interaction between adipocytes and iNKT cells may modulate adipose tissue inflammation in obesity.
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73
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Rhost S, Sedimbi S, Kadri N, Cardell SL. Immunomodulatory type II natural killer T lymphocytes in health and disease. Scand J Immunol 2012; 76:246-55. [PMID: 22724893 DOI: 10.1111/j.1365-3083.2012.02750.x] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Natural killer T (NKT) lymphocytes are αβ T cells activated by lipid-based ligands presented on the non-polymorphic CD1d-molecule. Type I NKT cells that carry an invariant Vα14 (in the mouse) or Vα24 (in humans) T cell receptor α-chain rearrangement have received significant attention for their involvement in a diversity of immune reactions. Their sister population, CD1d-restricted type II NKT cells, has been more difficult to study because of the lack of molecular markers that specify these cells. In the last few years, however, significant progress has been made, demonstrating that type II NKT cells have unique functions in immune responses to tumours and infections, in autoimmunity, obesity and graft-versus-host disease. Type II NKT cells appear more frequent than type I NKT cells in humans and accumulate in certain diseases such as ulcerative colitis, hepatitis and multiple myeloma. Recently, novel type II NKT cell ligands have been identified, and it is becoming clear that the type II NKT cell population may be oligoclonal. Here, we review the recent progress in the study of type II NKT cells, supporting the view that type II NKT cells may be attractive targets for immunotherapy.
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Affiliation(s)
- S Rhost
- Department of Microbiology and Immunology, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden
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74
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Van Kaer L, Parekh VV, Wu L. Invariant natural killer T cells as sensors and managers of inflammation. Trends Immunol 2012; 34:50-8. [PMID: 23017731 DOI: 10.1016/j.it.2012.08.009] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2012] [Revised: 08/28/2012] [Accepted: 08/28/2012] [Indexed: 02/08/2023]
Abstract
Invariant natural killer T (iNKT) cells are a subset of innate-like lymphocytes that recognize glycolipid antigens bound by the major histocompatibility complex (MHC)-class-I-related protein CD1d. iNKT cells are activated early during a variety of infections and inflammatory diseases and contribute to the subsequent development of adaptive immune responses. Consequently, iNKT cells play a critical role in the development and resolution of inflammatory diseases and represent attractive targets for the development of immunotherapies. Recent studies have provided important insight into the mechanisms by which iNKT cells become activated in response to diverse inflammatory stimuli. These new findings should be instrumental to promote the immunomodulatory properties of iNKT cells for treatment of inflammatory diseases.
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Affiliation(s)
- Luc Van Kaer
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.
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75
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Lynch L, Nowak M, Varghese B, Clark J, Hogan AE, Toxavidis V, Balk SP, O'Shea D, O'Farrelly C, Exley MA. Adipose tissue invariant NKT cells protect against diet-induced obesity and metabolic disorder through regulatory cytokine production. Immunity 2012; 37:574-87. [PMID: 22981538 DOI: 10.1016/j.immuni.2012.06.016] [Citation(s) in RCA: 384] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2012] [Revised: 05/23/2012] [Accepted: 06/07/2012] [Indexed: 12/13/2022]
Abstract
Invariant natural killer T (iNKT) cells are evolutionarily conserved innate T cells that influence inflammatory responses. We have shown that iNKT cells, previously thought to be rare in humans, were highly enriched in human and murine adipose tissue, and that as adipose tissue expanded in obesity, iNKT cells were depleted, correlating with proinflammatory macrophage infiltration. iNKT cell numbers were restored in mice and humans after weight loss. Mice lacking iNKT cells had enhanced weight gain, larger adipocytes, fatty livers, and insulin resistance on a high-fat diet. Adoptive transfer of iNKT cells into obese mice or in vivo activation of iNKT cells via their lipid ligand, alpha-galactocylceramide, decreased body fat, triglyceride levels, leptin, and fatty liver and improved insulin sensitivity through anti-inflammatory cytokine production by adipose-derived iNKT cells. This finding highlights the potential of iNKT cell-targeted therapies, previously proven to be safe in humans, in the management of obesity and its consequences.
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Affiliation(s)
- Lydia Lynch
- Hematology/Oncology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA.
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76
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Schipper HS, Rakhshandehroo M, van de Graaf SFJ, Venken K, Koppen A, Stienstra R, Prop S, Meerding J, Hamers N, Besra G, Boon L, Nieuwenhuis EES, Elewaut D, Prakken B, Kersten S, Boes M, Kalkhoven E. Natural killer T cells in adipose tissue prevent insulin resistance. J Clin Invest 2012; 122:3343-54. [PMID: 22863618 DOI: 10.1172/jci62739] [Citation(s) in RCA: 161] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2012] [Accepted: 07/05/2012] [Indexed: 12/12/2022] Open
Abstract
Lipid overload and adipocyte dysfunction are key to the development of insulin resistance and can be induced by a high-fat diet. CD1d-restricted invariant natural killer T (iNKT) cells have been proposed as mediators between lipid overload and insulin resistance, but recent studies found decreased iNKT cell numbers and marginal effects of iNKT cell depletion on insulin resistance under high-fat diet conditions. Here, we focused on the role of iNKT cells under normal conditions. We showed that iNKT cell-deficient mice on a low-fat diet, considered a normal diet for mice, displayed a distinctive insulin resistance phenotype without overt adipose tissue inflammation. Insulin resistance was characterized by adipocyte dysfunction, including adipocyte hypertrophy, increased leptin, and decreased adiponectin levels. The lack of liver abnormalities in CD1d-null mice together with the enrichment of CD1d-restricted iNKT cells in both mouse and human adipose tissue indicated a specific role for adipose tissue-resident iNKT cells in the development of insulin resistance. Strikingly, iNKT cell function was directly modulated by adipocytes, which acted as lipid antigen-presenting cells in a CD1d-mediated fashion. Based on these findings, we propose that, especially under low-fat diet conditions, adipose tissue-resident iNKT cells maintain healthy adipose tissue through direct interplay with adipocytes and prevent insulin resistance.
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Affiliation(s)
- Henk S Schipper
- Department of Metabolic Diseases, University Medical Center Utrecht, Utrecht, the Netherlands
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77
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Schipper HS, Prakken B, Kalkhoven E, Boes M. Adipose tissue-resident immune cells: key players in immunometabolism. Trends Endocrinol Metab 2012; 23:407-15. [PMID: 22795937 DOI: 10.1016/j.tem.2012.05.011] [Citation(s) in RCA: 211] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2012] [Revised: 05/29/2012] [Accepted: 05/31/2012] [Indexed: 12/20/2022]
Abstract
Adipose tissue (AT) plays a pivotal role in whole-body lipid and glucose homeostasis. AT exerts metabolic control through various immunological mechanisms that instigated a new research field termed immunometabolism. Here, we review AT-resident immune cells and their role as key players in immunometabolism. In lean subjects, AT-resident immune cells have housekeeping functions ranging from apoptotic cell clearance to extracellular matrix remodeling and angiogenesis. However, obesity provides bacterial and metabolic danger signals that mimic bacterial infection, and drives a shift in immune-cell phenotypes and numbers, classified as a prototypic T helper 1 (Th1) inflammatory response. The resulting AT inflammation and insulin resistance link obesity to its metabolic sequel, and suggests that targeted immunomodulatory interventions may be beneficial for obese patients.
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Affiliation(s)
- Henk S Schipper
- Department of Pediatric Immunology and Infectious Diseases, University Medical Center Utrecht and Center for Molecular and Cellular Intervention, Wilhelmina Children's Hospital, Utrecht, The Netherlands
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78
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Andoh Y, Ogura H, Satoh M, Shimano K, Okuno H, Fujii S, Ishimori N, Eshima K, Tamauchi H, Otani T, Nakai Y, Van Kaer L, Tsutsui H, Onoé K, Iwabuchi K. Natural killer T cells are required for lipopolysaccharide-mediated enhancement of atherosclerosis in apolipoprotein E-deficient mice. Immunobiology 2012; 218:561-9. [PMID: 22954709 DOI: 10.1016/j.imbio.2012.07.022] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2011] [Revised: 07/11/2012] [Accepted: 07/14/2012] [Indexed: 12/12/2022]
Abstract
Lipopolysaccharide (LPS) has been shown to accelerate atherosclerosis and to increase the prevalence of IL-4-producing natural killer T (NKT) cells in various tissues. However, the role of NKT cells in the development of LPS-induced atherosclerotic lesions has not been fully tested in NKT cell-deficient mice. Here, we examined the lesion development in apolipoprotein E knockout (apoE-KO) mice and apoE-KO mice on an NKT cell-deficient, CD1d knockout (CD1d-KO) background (apoE-CD1d double knockout; DKO). LPS (0.5 μg/g body weight/wk) or phosphate-buffered saline (PBS) was intraperitoneally administered to apoE-KO and DKO mice (8-wk old) for 5 wk and atherosclerotic lesion areas were quantified thereafter. Consistent with prior reports, NKT cell-deficient DKO mice showed milder atherosclerotic lesions than apoE-KO mice. Notably, LPS administration significantly increased the lesion size in apoE-KO, but not in DKO mice, compared to PBS controls. Our findings suggest that LPS, and possibly LPS-producing bacteria, aggravate the development of atherosclerosis primarily through NKT cell activation and subsequent collaboration with NK cells.
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Affiliation(s)
- Yasuhiro Andoh
- Division of Immunobiology, Research Section of Pathophysiology, Institute for Genetic Medicine, Hokkaido University, Sapporo, Japan
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79
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Ji Y, Sun S, Xia S, Yang L, Li X, Qi L. Short term high fat diet challenge promotes alternative macrophage polarization in adipose tissue via natural killer T cells and interleukin-4. J Biol Chem 2012; 287:24378-86. [PMID: 22645141 DOI: 10.1074/jbc.m112.371807] [Citation(s) in RCA: 111] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Inflammation in adipose tissue plays an important role in the pathogenesis of obesity-associated complications. However, the detailed cellular events underlying the inflammatory changes at the onset of obesity have not been characterized. Here we show that an acute HFD challenge is unexpectedly associated with elevated alternative (M2) macrophage polarization in adipose tissue mediated by Natural Killer T (NKT) cells. Upon 4d HFD feeding, NKT cells are activated, promote M2 macrophage polarization and induce arginase 1 expression via interleukin (IL)-4 in adipose tissue, not in the liver. In NKT-deficient CD1d(-/-) mice, M2 macrophage polarization in adipose tissue is reduced while systemic glucose homeostasis and insulin tolerance are impaired upon 4d HFD challenge. Thus, our study demonstrate, for the first time to our knowledge, that acute HFD feeding is associated with remarkably pronounced and dynamic immune responses in adipose tissue, and adipose-resident NKT cells may link acute HFD feeding with inflammation.
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Affiliation(s)
- Yewei Ji
- Division of Nutritional Sciences, Cornell University, Ithaca, New York 14853, USA
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80
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Subrahmanyam PB, Sun W, East JE, Li J, Webb TJ. Natural killer T cell based Immunotherapy. ACTA ACUST UNITED AC 2012; 3:144. [PMID: 24089657 DOI: 10.4172/2157-7560.1000144] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Natural killer T (NKT) cells play an important immunoregulatory role and are thought to bridge the innate and adaptive immune responses. Following activation through cognate interactions with lipid antigen presented in the context of CD1d molecules, NKT cells rapidly produce a plethora of cytokines and can also mediate cytotoxicity. Due to their potent effector functions, extensive research has been performed to increase our understanding on how to effectively modulate these cells. In fact, NKT cell agonists have been used as vaccine adjuvants to enhance antigen specific T and B cell responses to infections and malignancy. In this review, we will focus on recent advances in NKT cell-based vaccination strategies. Given the role that NKT cells play in autoimmune disease, infectious diseases, cancer, transplant immunology and dermatology, it is important to understand how to effectively guide their effector functions in order to develop novel immunotherapeutic strategies.
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Affiliation(s)
- Priyanka B Subrahmanyam
- Department of Microbiology and Immunology, University of Maryland School of Medicine, the Marlene and Stewart Greenebaum Cancer Center, Baltimore, Maryland 21201
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