101
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Nguyen NT, Nakahama T, Le DH, Van Son L, Chu HH, Kishimoto T. Aryl hydrocarbon receptor and kynurenine: recent advances in autoimmune disease research. Front Immunol 2014; 5:551. [PMID: 25400638 PMCID: PMC4212680 DOI: 10.3389/fimmu.2014.00551] [Citation(s) in RCA: 100] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2014] [Accepted: 10/16/2014] [Indexed: 12/13/2022] Open
Abstract
Aryl hydrocarbon receptor (AHR) is thought to be a crucial factor in the regulation of immune responses. Many AHR-mediated immunoregulatory mechanisms have been discovered, and this knowledge may enhance our understanding of the molecular pathogenesis of autoimmune inflammatory syndromes such as collagen-induced arthritis, experimental autoimmune encephalomyelitis, and experimental colitis. Recent findings have elucidated the critical link between AHR and indoleamine 2,3-dioxygenase (IDO) in the development of regulatory T cells and Th17 cells, which are key factors in a variety of human autoimmune diseases. Induction of IDO and IDO-mediated tryptophan catabolism, together with its downstream products such as kynurenine, is an important immunoregulatory mechanism underlying immunosuppression, tolerance, and immunity. Recent studies revealed that induction of IDO depends on AHR expression. This review summarizes the most current findings regarding the functions of AHR and IDO in immune cells as they relate to the pathogenesis of autoimmune diseases in response to various stimuli. We also discuss the potential link between AHR and IDO/tryptophan metabolites, and the involvement of several novel related factors (such as microRNA) in the development of autoimmune diseases. These novel factors represent potential therapeutic targets for the treatment of autoimmune disorders.
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Affiliation(s)
- Nam Trung Nguyen
- Laboratory of Immune Regulation, WPI-Immunology Frontier Research Center, Osaka University , Suita , Japan ; National Key Laboratory of Gene Technology, Institute of Biotechnology, Vietnam Academy of Science and Technology , Hanoi , Vietnam
| | - Taisuke Nakahama
- Laboratory of Immune Regulation, WPI-Immunology Frontier Research Center, Osaka University , Suita , Japan ; Department of RNA Biology and Neuroscience, Graduate School of Medicine Osaka University , Suita , Japan
| | - Duc Hoang Le
- National Key Laboratory of Gene Technology, Institute of Biotechnology, Vietnam Academy of Science and Technology , Hanoi , Vietnam
| | - Le Van Son
- National Key Laboratory of Gene Technology, Institute of Biotechnology, Vietnam Academy of Science and Technology , Hanoi , Vietnam
| | - Ha Hoang Chu
- National Key Laboratory of Gene Technology, Institute of Biotechnology, Vietnam Academy of Science and Technology , Hanoi , Vietnam
| | - Tadamitsu Kishimoto
- Laboratory of Immune Regulation, WPI-Immunology Frontier Research Center, Osaka University , Suita , Japan
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102
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Ahmed T, Auble D, Berkley JA, Black R, Ahern PP, Hossain M, Hsieh A, Ireen S, Arabi M, Gordon JI. An evolving perspective about the origins of childhood undernutrition and nutritional interventions that includes the gut microbiome. Ann N Y Acad Sci 2014; 1332:22-38. [PMID: 25118072 PMCID: PMC4514967 DOI: 10.1111/nyas.12487] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The Sackler Institute for Nutrition Science and the World Health Organization (WHO) have worked together to formulate a research agenda for nutrition science. Undernutrition of children has profound effects on health, development, and achievement of full human capacity. Undernutrition is not simply caused by a lack of food, but results from a complex interplay of intra- and intergenerational factors. Representative preclinical models and comprehensive well-controlled longitudinal clinical studies are needed to further understand the contributions and the interrelationships among these factors and to develop interventions that are effective and durable. This paper summarizes work on mechanisms underlying the varied manifestations of childhood undernutrition and discusses current gaps in knowledge and challenges to our understanding of undernutrition and infection/immunity throughout the human life cycle, focusing on early childhood growth. It proposes a series of basic and clinical studies to address this global health challenge.
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Affiliation(s)
- Tahmeed Ahmed
- Centre for Nutrition and Food Security, International Centre for Diarrhoeal Disease Research, Dhaka, Bangladesh
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103
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Eleftheriadis T, Pissas G, Antoniadi G, Spanoulis A, Liakopoulos V, Stefanidis I. Indoleamine 2,3-dioxygenase increases p53 levels in alloreactive human T cells, and both indoleamine 2,3-dioxygenase and p53 suppress glucose uptake, glycolysis and proliferation. Int Immunol 2014; 26:673-84. [PMID: 25064493 DOI: 10.1093/intimm/dxu077] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Indoleamine 2,3-dioxygenase (IDO) suppresses adaptive immunity by inhibiting T-cell proliferation and altering glucose metabolism. The tumor suppressor p53 also alters these cellular processes with similar results. The effect of IDO on p53 and on glucose metabolism was evaluated in alloreactive T cells. Mixed-lymphocyte reactions (MLRs) were performed in the presence or not of the IDO inhibitor, 1-dl-methyl-tryptophan (1-MT) and/or the p53 inhibitor, pifithrin-α (PFT). Cell proliferation, glucose consumption and lactate production were assessed. 1-MT increased cell proliferation, glucose influx and lactate production, whereas PFT enhanced cell proliferation and glucose influx, leaving lactate production unaffected. In MLR-derived T cells, protein analysis revealed that IDO activated general control non-derepressible 2 kinase and induced p53, p-p53 (p53 phosphorylated at serine 15) and p21. In addition, both IDO and p53 decreased glucose transporter 1 and TP53-induced glycolysis and apoptosis regulator and increased synthesis of cytochrome c oxidase 2. IDO also reduced lactate dehydrogenase-A and glutaminase 2 levels, whereas p53 left them unaffected. Neither 1-MT nor PFT affected glucose-6-phosphate dehydrogenase. In conclusion, in alloreactive T cells, IDO increases p53 levels, and both IDO and p53 inhibit cell proliferation, glucose consumption and glycolysis. Lactate production and glutaminolysis are also suppressed by IDO, but not by p53.
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Affiliation(s)
- Theodoros Eleftheriadis
- Department of Nephrology, Medical School, University of Thessaly, Neo Ktirio, Mezourlo Hill, 41110 Larissa, Greece
| | - Georgios Pissas
- Department of Nephrology, Medical School, University of Thessaly, Neo Ktirio, Mezourlo Hill, 41110 Larissa, Greece
| | - Georgia Antoniadi
- Department of Nephrology, Medical School, University of Thessaly, Neo Ktirio, Mezourlo Hill, 41110 Larissa, Greece
| | - Aginor Spanoulis
- Department of Nephrology, Medical School, University of Thessaly, Neo Ktirio, Mezourlo Hill, 41110 Larissa, Greece
| | - Vassilios Liakopoulos
- Department of Nephrology, Medical School, University of Thessaly, Neo Ktirio, Mezourlo Hill, 41110 Larissa, Greece
| | - Ioannis Stefanidis
- Department of Nephrology, Medical School, University of Thessaly, Neo Ktirio, Mezourlo Hill, 41110 Larissa, Greece
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104
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Kong YCM, Flynn JC. Opportunistic Autoimmune Disorders Potentiated by Immune-Checkpoint Inhibitors Anti-CTLA-4 and Anti-PD-1. Front Immunol 2014; 5:206. [PMID: 24904570 PMCID: PMC4032988 DOI: 10.3389/fimmu.2014.00206] [Citation(s) in RCA: 90] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2014] [Accepted: 04/25/2014] [Indexed: 12/16/2022] Open
Abstract
To improve the efficacy of immunotherapy for cancer and autoimmune diseases, recent ongoing and completed clinical trials have focused on specific targets to redirect the immune network toward eradicating a variety of tumors and ameliorating the self-destructive process. In a previous review, both systemic immunomodulators and monoclonal antibodies (mAbs), anti-CTLA-4, and anti-CD52, were discussed regarding therapeutics and autoimmune sequelae, as well as predisposing factors known to exacerbate immune-related adverse events (irAEs). This review will focus on immune-checkpoint inhibitors, and the data from most clinical trials involve blockade with anti-CTLA-4 such as ipilimumab. However, despite the mild to severe irAEs observed with ipilimumab in ~60% of patients, overall survival (OS) averaged ~22-25% at 3-5 years. To boost OS, other mAbs targeting programed death-1 and its ligand are undergoing clinical trials as monotherapy or dual therapy with anti-CTLA-4. Therapeutic combinations may generate different spectrum of opportunistic autoimmune disorders. To simulate clinical scenarios, we have applied regulatory T cell perturbation to murine models combined to examine the balance between thyroid autoimmunity and tumor-specific immunity.
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Affiliation(s)
- Yi-Chi M Kong
- Department of Immunology and Microbiology, Wayne State University School of Medicine , Detroit, MI , USA
| | - Jeffrey C Flynn
- Department of Orthopaedic Surgery, Providence Hospital and Medical Centers , Southfield, MI , USA
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105
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Taguchi A, Niwa M, Hoshi M, Saito K, Masutani T, Hisamatsu K, Kobayashi K, Hatano Y, Tomita H, Hara A. Indoleamine 2,3-dioxygenase 1 is upregulated in activated microglia in mice cerebellum during acute viral encephalitis. Neurosci Lett 2014; 564:120-5. [DOI: 10.1016/j.neulet.2014.01.051] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Revised: 01/16/2014] [Accepted: 01/24/2014] [Indexed: 11/25/2022]
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106
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Orsini H, Araujo LP, Maricato JT, Guereschi MG, Mariano M, Castilho BA, Basso AS. GCN2 kinase plays an important role triggering the remission phase of experimental autoimmune encephalomyelitis (EAE) in mice. Brain Behav Immun 2014; 37:177-86. [PMID: 24362236 DOI: 10.1016/j.bbi.2013.12.012] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2013] [Revised: 12/12/2013] [Accepted: 12/16/2013] [Indexed: 11/28/2022] Open
Abstract
Experimental autoimmune encephalomyelitis (EAE) has been widely employed as a model to study multiple sclerosis (MS) and indeed has allowed some important advances in our comprehension of MS pathogenesis. Several pieces of evidence suggest that infiltrating Th1 and Th17 lymphocytes are important players leading to CNS demyelination and lesion during the peak of murine EAE. Subsequently, effector T cell responses rapidly decline and the recovery phase of the disease strongly correlates with the expression of anti-inflammatory cytokines and the enrichment of Foxp3+ regulatory T (Treg) cells within the target organ. However, the mechanisms leading to the increased presence of Treg cells and to the remission phase of the disease are still poorly understood. Recent researches demonstrated that chemically induced amino-acid starvation response might suppress CNS immune activity. Here we verified an important participation of the general control nonrepressible 2 (GCN2), a key regulator kinase of the amino-acid starvation response, in the development of the remission phase of EAE in C57BL/6 mice. By immunizing wild type C57BL/6 (WT) and GCN2 knock-out mice (GCN2 KO) with myelin oligodendrocyte glycoprotein peptide (MOG35-55), it was noticed that GCN2 KO mice did not develop the remission phase of the disease and this was associated with higher levels of CNS inflammation and increased presence of effector T cells (Th1/Th17). These animals also showed lower frequency of Treg cells within the CNS as compared to WT animals. Higher expression of indoleamine 2,3-dioxygenase (IDO) and higher frequency of plasmacytoid dendritic cells (pDCs) were found at the peak of the disease in the CNS of WT animals. Our results suggest that the GCN2 kinase-dependent sensing of IDO activity represents an important trigger to the EAE remission phase. The IDO-mediated immunoregulatory events may include the arresting of effector T cell responses and the differentiation/expansion of Treg cells within the target organ.
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Affiliation(s)
- Heloisa Orsini
- Departamento de Microbiologia, Imunologia e Parasitologia, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Leandro P Araujo
- Departamento de Microbiologia, Imunologia e Parasitologia, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Juliana T Maricato
- Departamento de Microbiologia, Imunologia e Parasitologia, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Marcia G Guereschi
- Departamento de Microbiologia, Imunologia e Parasitologia, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Mario Mariano
- Departamento de Microbiologia, Imunologia e Parasitologia, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Beatriz A Castilho
- Departamento de Microbiologia, Imunologia e Parasitologia, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Alexandre S Basso
- Departamento de Microbiologia, Imunologia e Parasitologia, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil.
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107
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Terlecki P, Pawlik P, Iwaniuk A, Kocki T, Przywara S, Ilzecki M, Zubilewicz T, Kowalczyk M, Parada-Turska J, Dąbrowski W. Carotid surgery affects plasma kynurenic acid concentration: a pilot study. Med Sci Monit 2014; 20:303-10. [PMID: 24561546 PMCID: PMC3937007 DOI: 10.12659/msm.890212] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Accepted: 01/06/2014] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND An increase in plasma kynurenic acid (KYNA) concentration has been observed following surgery, inflammation, and cerebral pathologies. The aim of the present study was to analyze the changes in plasma KYNA concentration in patients undergoing carotid surgery (CS). MATERIAL AND METHODS Adult patients undergoing elective carotid endarterectomy (CEA) or carotid angioplasty with stent placement (CAS) were studied. Plasma KYNA concentrations were analyzed before surgery and at 4 time points after CS. The amount of inflammation was measured as neutrophil-lymphocyte ratio (NLR). RESULTS Forty patients (10 female and 30 male) aged 55-86 years of age were evaluated in this study. In patients with unstable carotid plaque, the plasma KYNA concentration was higher than in patients with stable carotid plaque. Moreover, the NLR was significantly higher in patients with unstable carotid plaque undergoing CEA than in patients undergoing CAS. Plasma KYNA concentration increased after surgery in patients undergoing CEA and CAS. There was a strong correlation between plasma KYNA concentration and NLR in patients with postoperative neurological disorders. CONCLUSIONS CS increases plasma KYNA concentration, and changes in plasma KYNA concentration can indicate neurologic outcomes in patients undergoing CS.
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Affiliation(s)
- Piotr Terlecki
- Department of Vascular Surgery and Angiology Medical University of Lublin, Lublin, Poland
| | - Paulina Pawlik
- Department of Anesthesiology and Intensive Therapy Medical University of Lublin, Lublin, Poland
| | - Adam Iwaniuk
- Department of Clinical and Experimental Pharmacology Medical University of Lublin, Lublin, Poland
| | - Tomasz Kocki
- Department of Clinical and Experimental Pharmacology Medical University of Lublin, Lublin, Poland
| | - Stanisław Przywara
- Department of Vascular Surgery and Angiology Medical University of Lublin, Lublin, Poland
| | - Marek Ilzecki
- Department of Vascular Surgery and Angiology Medical University of Lublin, Lublin, Poland
| | - Tomasz Zubilewicz
- Department of Vascular Surgery and Angiology Medical University of Lublin, Lublin, Poland
| | - Michał Kowalczyk
- Department of Anesthesiology and Intensive Therapy Medical University of Lublin, Lublin, Poland
| | - Jolanta Parada-Turska
- Department of Rheumatology and Connective Tissue Diseases Medical University of Lublin, Lublin, Poland
| | - Wojciech Dąbrowski
- Department of Anesthesiology and Intensive Therapy Medical University of Lublin, Lublin, Poland
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108
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Campbell BM, Charych E, Lee AW, Möller T. Kynurenines in CNS disease: regulation by inflammatory cytokines. Front Neurosci 2014; 8:12. [PMID: 24567701 PMCID: PMC3915289 DOI: 10.3389/fnins.2014.00012] [Citation(s) in RCA: 265] [Impact Index Per Article: 26.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2013] [Accepted: 01/20/2014] [Indexed: 12/27/2022] Open
Abstract
The kynurenine pathway (KP) metabolizes the essential amino acid tryptophan and generates a number of neuroactive metabolites collectively called the kynurenines. Segregated into at least two distinct branches, often termed the “neurotoxic” and “neuroprotective” arms of the KP, they are regulated by the two enzymes kynurenine 3-monooxygenase and kynurenine aminotransferase, respectively. Interestingly, several enzymes in the pathway are under tight control of inflammatory mediators. Recent years have seen a tremendous increase in our understanding of neuroinflammation in CNS disease. This review will focus on the regulation of the KP by inflammatory mediators as it pertains to neurodegenerative and psychiatric disorders.
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Affiliation(s)
- Brian M Campbell
- Neuroinflammation Disease Biology Unit, Lundbeck Research USA Paramus, NJ, USA
| | - Erik Charych
- Neuroinflammation Disease Biology Unit, Lundbeck Research USA Paramus, NJ, USA
| | - Anna W Lee
- Neuroinflammation Disease Biology Unit, Lundbeck Research USA Paramus, NJ, USA
| | - Thomas Möller
- Neuroinflammation Disease Biology Unit, Lundbeck Research USA Paramus, NJ, USA
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109
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White M, Webster G, O’Sullivan D, Stone S, La Flamme AC. Targeting innate receptors with MIS416 reshapes Th responses and suppresses CNS disease in a mouse model of multiple sclerosis. PLoS One 2014; 9:e87712. [PMID: 24498172 PMCID: PMC3909208 DOI: 10.1371/journal.pone.0087712] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Accepted: 01/02/2014] [Indexed: 01/27/2023] Open
Abstract
Modification of the innate immune cell environment has recently been recognized as a viable treatment strategy for reducing autoimmune disease pathology. MIS416 is a microparticulate immune response modifier that targets myeloid cells, activating cytosolic receptors NOD2 and TLR9, and has completed a phase 1b/2a trial for the treatment of secondary progressive multiple sclerosis. Using a mouse model of multiple sclerosis, we are investigating the pathways by which activation of TLR9 and NOD2 may modify the innate immune environment and the subsequent T cell-mediated autoimmune responses. We have found that MIS416 has profound effects on the Th subset balance by depressing antigen-specific Th1, Th17, and Th2 development. These effects coincided with an expansion of specific myeloid subpopulations and increased levels of MIS416-stimulated IFN-γ by splenocytes. Additionally, systemic IFN-γ serum levels were enhanced and correlated strongly with disease reduction, and the protective effect of MIS416 was abrogated in IFN-γ-deficient animals. Finally, treatment of secondary progressive MS patients with MIS416 similarly elevated the levels of IFN-γ and IFN-γ-associated proteins in the serum. Together, these studies demonstrate that administration of MIS416, which targets innate cells, reshapes autoimmune T cell responses and leads to a significant reduction in CNS inflammation and disease.
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Affiliation(s)
- Madeleine White
- School of Biological Sciences, Victoria University of Wellington, Wellington, New Zealand
| | - Gill Webster
- Innate Immunotherapeutics, Auckland, New Zealand
| | - David O’Sullivan
- School of Biological Sciences, Victoria University of Wellington, Wellington, New Zealand
| | - Sarrabeth Stone
- School of Biological Sciences, Victoria University of Wellington, Wellington, New Zealand
| | - Anne Camille La Flamme
- School of Biological Sciences, Victoria University of Wellington, Wellington, New Zealand
- Malaghan Institute of Medical Research, Wellington, New Zealand
- * E-mail:
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110
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Naegele M, Martin R. The good and the bad of neuroinflammation in multiple sclerosis. HANDBOOK OF CLINICAL NEUROLOGY 2014; 122:59-87. [PMID: 24507513 DOI: 10.1016/b978-0-444-52001-2.00003-0] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Multiple sclerosis (MS) is the most common inflammatory, demyelinating, neurodegenerative disorder of the central nervous system (CNS). It is widely considered a T-cell mediated autoimmune disease that develops in genetically susceptible individuals, possibly under the influence of certain environmental trigger factors. The invasion of autoreactive CD4+ T-cells into the CNS is thought to be a central step that initiates the disease. Several other cell types, including CD8+ T-cells, B-cells and phagocytes appear to be involved in causing inflammation and eventually neurodegeneration. But inflammation is not entirely deleterious in MS. Evidence has accumulated in the recent years that show the importance of regulatory immune mechanisms which restrain tissue damage and initiate regeneration. More insight into the beneficial aspects of neuroinflammation might allow us to develop new treatment strategies for this enigmatic disease.
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Affiliation(s)
- Matthias Naegele
- Institute for Neuroimmunology and Clinical Multiple Sclerosis Research, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Roland Martin
- Neuroimmunology and MS Research, Neurology Clinic, University Hospital, Zurich, Switzerland.
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111
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Hartung HP, Aktas O, Menge T, Kieseier BC. Immune regulation of multiple sclerosis. HANDBOOK OF CLINICAL NEUROLOGY 2014; 122:3-14. [PMID: 24507511 DOI: 10.1016/b978-0-444-52001-2.00001-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Multiple sclerosis (MS) is considered a prototype inflammatory autoimmune disorder of the central nervous system (CNS). The etiology of this disease remains unknown, but an interplay between as yet unidentified environmental factors and susceptibility genes appears most likely. In consequence, these factors trigger a cascade, involving an inflammatory response within the CNS that results in demyelination, oligodendrocyte death, axonal damage, gliosis, and neurodegeneration. How these complex traits translate into the clinical presentation of the disease is a focus of ongoing research. The central hypothesis is that T lymphocytes with receptors for CNS myelin components are driving the disease. The initial activation of autoreactive lymphocytes is thought to take place in the systemic lymphoid organs, most likely through molecular mimickry or nonspecifically through bystander activation. These autoreactive lymphocytes can migrate to the CNS where they become reactivated upon encountering their target antigen, initiating an autoimmune inflammatory attack. This ultimately leads to demyelination and axonal damage. This chapter focuses on the role of T and B lymphocytes in the immunopathogenesis of MS.
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Affiliation(s)
- Hans-Peter Hartung
- Department of Neurology, Medical Faculty, Heinrich-Heine University, Düsseldorf, Germany.
| | - Orhan Aktas
- Department of Neurology, Medical Faculty, Heinrich-Heine University, Düsseldorf, Germany
| | - Til Menge
- Department of Neurology, Medical Faculty, Heinrich-Heine University, Düsseldorf, Germany
| | - Bernd C Kieseier
- Department of Neurology, Medical Faculty, Heinrich-Heine University, Düsseldorf, Germany
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112
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Abstract
High levels of several proinflammatory components of the immune system, such as interleukin-6, C-reactive protein, tumor necrosis factor (TNF)-α, or neopterin in patients suffering from major depression (MD) point to the involvement of an inflammatory process in the pathophysiology of MD. The direct and indirect effects of cytokines on neurotransmitter storage and release - mediated by microglia cells and astrocytes - are discussed. The tryptophan/kynurenine metabolism is one of the indirect mechanisms because the enzyme indoleamine 2,3-dioxygenase - a key enzyme of this metabolism in the central nervous system - is driven by pro- and anti-inflammatory cytokines and degrades serotonin. Moreover, neuroactive kynurenines such as kynurenic acid and quinolinic acid act on the glutamatergic neurotransmission as N-methyl-D-aspartate antagonists and agonists, respectively. Alterations of the serotonergic, noradrenergic and glutamatergic neurotransmission have been shown with low-level neuroinflammation and may be involved in symptom generation. Epidemiological and clinical studies show a role for inflammation as a risk factor for MD. A large-scale epidemiological study in MD clearly demonstrates that severe infections and autoimmune disorders are lifetime risk factors for MD. The vulnerability-stress-inflammation model matches with this view as stress may increase proinflammatory cytokines and even contribute to a lasting proinflammatory state. Further support comes from the therapeutic benefit of anti-inflammatory medications such as the cyclo-oxygenase-2 inhibitors, TNF-α antagonists and others, and the anti-inflammatory and immunomodulatory intrinsic effects of antidepressants.
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Affiliation(s)
- Norbert Müller
- Department of Psychiatry and Psychotherapy, Ludwig-Maximilian University of Munich, Munich, Germany
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113
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Inhibition of indoleamine 2,3-dioxygenase in mixed lymphocyte reaction affects glucose influx and enzymes involved in aerobic glycolysis and glutaminolysis in alloreactive T-cells. Hum Immunol 2013; 74:1501-9. [DOI: 10.1016/j.humimm.2013.08.268] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Revised: 07/30/2013] [Accepted: 08/10/2013] [Indexed: 01/26/2023]
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114
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Quintana FJ. Regulation of central nervous system autoimmunity by the aryl hydrocarbon receptor. Semin Immunopathol 2013; 35:627-35. [PMID: 23999753 PMCID: PMC3819215 DOI: 10.1007/s00281-013-0397-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Accepted: 08/22/2013] [Indexed: 12/22/2022]
Abstract
The ligand-activated transcription factor aryl hydrocarbon receptor controls the activity of several components of the immune system, many of which play an important role in neuroinflammation. This review discusses the role of AhR in T cells and dendritic cells, its relevance for the control of autoimmunity in the central nervous system, and its potential as a therapeutic target for immune-mediated disorders.
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Affiliation(s)
- Francisco J Quintana
- Center for Neurologic Diseases, Brigham and Women's Hospital, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, MA, 02115, USA,
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115
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Guiton R, Henry-Berger J, Drevet JR. The immunobiology of the mammalian epididymis: the black box is now open! Basic Clin Androl 2013; 23:8. [PMID: 25780570 PMCID: PMC4349724 DOI: 10.1186/2051-4190-23-8] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Accepted: 08/20/2013] [Indexed: 01/04/2023] Open
Abstract
Spermatozoa represent an immunologic challenge for the mammalian males. They are produced long after the establishment of the immune library of the individual and harbor specific spermatic antigens that are found nowhere else in other organs, tissues and cells. Consequently, spermatozoa are somehow “foreign” to the male adaptive immune system. In order not to elicit autoimmune responses that would be detrimental for male fertility, spermatozoa should be either physically separated from the adaptive immune response and/or, the immune system challenged by spermatic antigens must be efficiently silenced. Within the mammalian male genital tract it becomes more and more obvious that a range of strategies are at stake to ensure that the immune-stranger spermatozoa do not constitute an immunological issue. In this review the focus will be on the immune status of the epididymis tubule, in which spermatozoa that have left the testes will mature for approximately 2 weeks and may be stored for prolonged period of time. How the epididymal immune environment compares to that of the testis and what are the immune regulatory processes at work in the epididymal compartment will only be briefly described. Instead, this review will focus on recent data that highlight epididymal immune regulatory actors that partly explain/illustrate the rather complicated, fragile but nevertheless robust immune environment of the epididymis.
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Affiliation(s)
- Rachel Guiton
- GReD Laboratory, CNRS UMR 6293 - INSERM U1103, Clermont Université, Clermont-Ferrand, France
| | - Joelle Henry-Berger
- GReD Laboratory, CNRS UMR 6293 - INSERM U1103, Clermont Université, Clermont-Ferrand, France
| | - Joël R Drevet
- GReD Laboratory, CNRS UMR 6293 - INSERM U1103, Clermont Université, Clermont-Ferrand, France
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116
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Klose J, Schmidt NO, Melms A, Dohi M, Miyazaki JI, Bischof F, Greve B. Suppression of experimental autoimmune encephalomyelitis by interleukin-10 transduced neural stem/progenitor cells. J Neuroinflammation 2013; 10:117. [PMID: 24053338 PMCID: PMC3852052 DOI: 10.1186/1742-2094-10-117] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Accepted: 09/08/2013] [Indexed: 02/07/2023] Open
Abstract
Neural stem/progenitor cells (NSPCs) have the ability to migrate into the central nervous system (CNS) to replace damaged cells. In inflammatory CNS disease, cytokine transduced neural stem cells may be used as vehicles to specifically reduce inflammation and promote cell replacement. In this study, we used NSPCs overexpressing IL-10, an immunomodulatory cytokine, in an animal model for CNS inflammation and multiple sclerosis (MS). Intravenous injection of IL-10 transduced neural stem/progenitor cells (NSPCIL-10) suppressed myelin oligodendrocyte glycoprotein aa 35–55 (MOG35-55)- induced experimental autoimmune encephalomyelitis (EAE) and, following intravenous injection, NSPCIL-10 migrated to peripheral lymphoid organs and into the CNS. NSPCIL-10 suppressed antigen-specific proliferation and proinflammatory cytokine production of lymph node cells obtained from MOG35-55 peptide immunized mice. In this model, IL-10 producing NSPCs act via a peripheral immunosuppressive effect to attenuate EAE.
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Affiliation(s)
- Juliane Klose
- Center of Neurology, Hertie-Institute for Clinical Brain Research, University of Tübingen, Otfried-Müller-Strasse 27, 72076 Tübingen, Germany.
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Monsonego A, Nemirovsky A, Harpaz I. CD4 T cells in immunity and immunotherapy of Alzheimer's disease. Immunology 2013; 139:438-46. [PMID: 23534386 DOI: 10.1111/imm.12103] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2013] [Revised: 03/13/2013] [Accepted: 03/18/2013] [Indexed: 01/09/2023] Open
Abstract
Alzheimer's disease (AD) is the most common form of dementia, with prevalence progressively increasing with aging. Pathological hallmarks of the disease include accumulation of amyloid β-protein (Aβ) peptides and neurofibrillary tangles in the brain associated with glial activation and synaptotoxicity. In addition, AD involves peripheral and brain endogenous inflammatory processes that appear to enhance disease progression. More than a decade ago a new therapeutic paradigm emerged for AD, namely the activation of the adaptive immune system directly against the self-peptide Aβ, aimed at lowering its accumulation in the brain. This was the first time that a brain peptide was used to vaccinate human subjects in a manner similar to classic viral or bacterial vaccines. The vaccination approach has taken several forms, from initially active to passive and then back to modified active vaccines. As the first two approaches to date failed to show sufficient efficacy, the last is presently being evaluated in ongoing clinical trials. The present review summarizes the immunogenic characteristics of Aβ in humans and mice and discusses past, present and future Aβ-based immunotherapeutic approaches for AD. We emphasize potential pathogenic and beneficial roles of CD4 T cells in light of the pathogenesis and the general decline in T-cell responsiveness evident in the disease.
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Affiliation(s)
- Alon Monsonego
- The Shraga Segal Department of Microbiology and Immunology, Faculty of Health Sciences, The National Institute for Biotechnology in the Negev, Ben-Gurion University of the Negev, Beer-Sheva, Israel.
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Rohlman D, Punj S, Pennington J, Bradford S, Kerkvliet NI. Suppression of acute graft-versus-host response by TCDD is independent of the CTLA-4-IFN-γ-IDO pathway. Toxicol Sci 2013; 135:81-90. [PMID: 23798565 PMCID: PMC3748765 DOI: 10.1093/toxsci/kft140] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Accepted: 06/12/2013] [Indexed: 12/12/2022] Open
Abstract
Activation of the aryl hydrocarbon receptor (AhR) by its prototypic ligand, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), induces potent suppression of an acute graft-versus-host (GVH) response and prevents GVH disease (GVHD). Suppression is associated with development of a regulatory population of donor CD4(+) CD25(+)T-cells that express high levels of cytotoxic T-lymphocyte antigen 4 (CTLA-4). However, a direct link between these AhR-induced Tregs (AhR-Tregs) and suppression of GVHD remains to be shown. CTLA-4 is a negative regulator of T-cell responses and is associated with the induction of tolerogenic dendritic cells (DCs) that produce indoleamine 2,3-dioxygenase (IDO). We hypothesized that AhR-Tregs mediate suppression via their enhanced expression of CTLA-4, which, in turn, induces IFN-γ and IDO in host DCs. Subsequent depletion of tryptophan by IDO leads to termination of the donor T-cell response prior to development of effector CTL. Here, we show that despite increased expression of Ifng, Irf3, Irf7, Ido1, and Ido2 in the lymph nodes of TCDD-treated host mice, inhibition of IDO enzyme activity by 1-methyl-tryptophan was unable to relieve TCDD-mediated suppression of the GVH response. Furthermore, treatment with an anti-CTLA-4 antibody that blocks CTLA-4 signaling was also unable to alleviate TCDD-mediated suppression. Alternatively, we investigated the possibility that donor-derived AhR-Tregs produce IFN-γ to suppress effector CTL development. However, suppression of GVHD by TCDD was not affected by the use of Ifng-deficient donor cells. Together, these results indicate that neither overexpression of CTLA-4 nor production of IFN-γ by AhR-Tregs plays a major role in the manifestation of their immunosuppressive function in vivo.
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Affiliation(s)
- Diana Rohlman
- *Department of Environmental and Molecular Toxicology and
| | - Sumit Punj
- *Department of Environmental and Molecular Toxicology and
| | | | - Sam Bradford
- *Department of Environmental and Molecular Toxicology and
- †Environmental Health Sciences Center, Oregon State University, Corvallis, Oregon 97331
| | - Nancy I. Kerkvliet
- *Department of Environmental and Molecular Toxicology and
- †Environmental Health Sciences Center, Oregon State University, Corvallis, Oregon 97331
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Immune privilege as an intrinsic CNS property: astrocytes protect the CNS against T-cell-mediated neuroinflammation. Mediators Inflamm 2013; 2013:320519. [PMID: 24023412 PMCID: PMC3760105 DOI: 10.1155/2013/320519] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2013] [Accepted: 07/09/2013] [Indexed: 12/26/2022] Open
Abstract
Astrocytes have many functions in the central nervous system (CNS). They support differentiation and homeostasis of neurons and influence synaptic activity. They are responsible for formation of the blood-brain barrier (BBB) and make up the glia limitans. Here, we review their contribution to neuroimmune interactions and in particular to those induced by the invasion of activated T cells. We discuss the mechanisms by which astrocytes regulate pro- and anti-inflammatory aspects of T-cell responses within the CNS. Depending on the microenvironment, they may become potent antigen-presenting cells for T cells and they may contribute to inflammatory processes. They are also able to abrogate or reprogram T-cell responses by inducing apoptosis or secreting inhibitory mediators. We consider apparently contradictory functions of astrocytes in health and disease, particularly in their interaction with lymphocytes, which may either aggravate or suppress neuroinflammation.
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Wen Q, Zhou L, Chen H, Zhang Y. N-(3', 4'-dimethoxycinnamonyl) anthranilic acid alleviated experimental colitis by inhibiting autoimmune response and inducing CD4+ CD25+ regulatory T cells production. J Gastroenterol Hepatol 2013; 28:1330-8. [PMID: 23663055 DOI: 10.1111/jgh.12266] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 04/15/2013] [Indexed: 02/05/2023]
Abstract
BACKGROUND AND AIM Crohn's disease treatments available today are not quite satisfactory. N-(3', 4'-dimethoxycinnamonyl) anthranilic acid (3, 4-DAA) has been proved to be effective in many autoimmune diseases. Therefore, we investigated the immunologic function of 3, 4-DAA on trinitrobenzene sulfonic acid (TNBS) colitis and human Crohn's disease. METHODS Mice with TNBS-induced colitis were treated with 3, 4-DAA or 1-methyl-tryptophan (1-MT). Colitis severity was assessed with clinical and histological scores. Cell proliferation, cytokine expression, and the percentage of CD4(+) CD25(+) T cells were measured in both mice and human samples. RESULTS In mice treated with 3, 4-DAA, the clinical and histological scores were decreased (P < 0.05); the proliferation of mesenteric lymph nodes (MLNs) cells and lamina propria mononuclear cells (LPMCs) were inhibited (P < 0.05); Th1 cytokine expressions were decreased (P < 0.05), and Th2 cytokine levels were increased (P < 0.05). 3, 4-DAA also induced CD4(+) CD25(+) T cells expression (5.88 ± 2.1 vs 11.03 ± 2.93, P < 0.05) in mice MLNs. Transfer of these cells into TNBS colitis mice resulted in the reduction of the disease activity index (DAI) and histological scores. In LPMCs isolated from human Crohn's disease, 3, 4-DAA had the same effect. It can inhibit the cell proliferation, decrease Th1 cytokine expressions (P < 0.05), and increase Th2 cytokine levels (P < 0.05). The percentage of CD4(+) CD25(+) T cells were also increased (1.60 ± 0.14 vs 2.45 ± 0.50, P < 0.05). 1-MT treatment led to opposite outcomes. CONCLUSION 3, 4-DAA can alleviate the severity of colitis through inhibiting Th1 cells response, promoting Th2 cytokines expression and inducing CD4(+) CD25(+) T cells expression.
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Affiliation(s)
- Quan Wen
- Department of Gastroenterology, West China Hospital of Sichuan University, Chengdu, Sichuan, China
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Jrad-Lamine A, Henry-Berger J, Damon-Soubeyrand C, Saez F, Kocer A, Janny L, Pons-Rejraji H, Munn DH, Mellor AL, Gharbi N, Cadet R, Guiton R, Aitken RJ, Drevet JR. Indoleamine 2,3-dioxygenase 1 (ido1) is involved in the control of mouse caput epididymis immune environment. PLoS One 2013; 8:e66494. [PMID: 23840489 PMCID: PMC3688773 DOI: 10.1371/journal.pone.0066494] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2012] [Accepted: 05/06/2013] [Indexed: 12/29/2022] Open
Abstract
The epididymis maintains a state of immune tolerance towards spermatozoa while also protecting them and itself against infection and acute inflammation. The immunosuppressive enzyme indoleamine 2,3-dioxygenase 1 (Ido1) participates in this delicate local equilibrium. Using the mouse Ido1(-/-) model, we show here that the absence of IDO1 expression leads in the epididymis but not in serum to (1) an increase in the inflammatory state as evidenced by changes in the content of cytokines and chemokines, (2) the engagement of a Th1-driven inflammatory response as evidenced by changes in the Th17/Treg as well as Th1/Th2 equilibria, as well as (3) differences in the content of lipid intermediates classically involved in inflammation. Despite this more pronounced inflammatory state, Ido1(-/-) animals succeed in preserving the local epididymal immune situation due to the activation of compensatory mechanisms that are discussed.
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Affiliation(s)
- Aicha Jrad-Lamine
- GReD laboratory, CNRS UMR 6293 - INSERM U1103 - Clermont Université, Aubière, France
- Faculté des Sciences de Tunis, El Manar, Département de Biologie, Mutuelleville, Tunis, Tunisia
| | - Joelle Henry-Berger
- GReD laboratory, CNRS UMR 6293 - INSERM U1103 - Clermont Université, Aubière, France
| | | | - Fabrice Saez
- GReD laboratory, CNRS UMR 6293 - INSERM U1103 - Clermont Université, Aubière, France
| | - Ayhan Kocer
- GReD laboratory, CNRS UMR 6293 - INSERM U1103 - Clermont Université, Aubière, France
| | - Laurent Janny
- GReD laboratory, CNRS UMR 6293 - INSERM U1103 - Clermont Université, Aubière, France
- CHU Estaing, Assistance Médicale à la Procréation, CECOS, Clermont-Ferrand, France
| | - Hanae Pons-Rejraji
- GReD laboratory, CNRS UMR 6293 - INSERM U1103 - Clermont Université, Aubière, France
- CHU Estaing, Assistance Médicale à la Procréation, CECOS, Clermont-Ferrand, France
| | - David H. Munn
- Immunotherapy Center and Department of Pediatrics, Medical College of Georgia, Augusta, Georgia, United States of America
| | - Andrew L. Mellor
- Immunotherapy Center and Department of Medicine, Medical College of Georgia, Augusta, Georgia, United States of America
| | - Najoua Gharbi
- Faculté des Sciences de Tunis, El Manar, Département de Biologie, Mutuelleville, Tunis, Tunisia
| | - Rémi Cadet
- GReD laboratory, CNRS UMR 6293 - INSERM U1103 - Clermont Université, Aubière, France
| | - Rachel Guiton
- GReD laboratory, CNRS UMR 6293 - INSERM U1103 - Clermont Université, Aubière, France
| | - Robert J. Aitken
- Priority Research Centre in Reproductive Science, School of Environmental and Life Sciences, University of Newcastle, Callaghan, Australia
| | - Joël R. Drevet
- GReD laboratory, CNRS UMR 6293 - INSERM U1103 - Clermont Université, Aubière, France
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Suarez-Fuentetaja N, Domenech-Garcia N, Paniagua-Martin MJ, Marzoa-Rivas R, Barge-Caballero E, Grille-Cancela Z, Pombo-Otero J, Muñiz-García J, Castro-Beiras A, Crespo-Leiro MG. Indoleamine, 2-3 dioxygenase activity could be an early marker of graft rejection in heart transplantation. Transplant Proc 2013; 44:2645-8. [PMID: 23146482 DOI: 10.1016/j.transproceed.2012.09.036] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
BACKGROUND The indoleamine, 2-3 dioxygenase (IDO) is an inducible intracellular enzyme with immunosuppressive effects mainly on lymphocyte populations. It has been postulated that indirect determination of IDO serum activity may be a marker of renal graft rejection, but its potential usefulness in heart transplantation (HT) is unknown. METHODS This longitudinal study included 98 HT patients (83% males) who survived ≥1 year. Mean age was 54.14 ± 11.57 years. Serum IDO activity was analyzed one month after HT by means of high performance liquid chromatography and correlated with the cumulative incidence of acute rejection (AR) during one-year follow-up. AR was defined as biopsy-proven ≥ ISHLT grade 2R rejection or empirically treated non-biopsy-proven rejection. The study sample was divided into two groups: AR group (n = 51), including patients who experienced at least one AR episode during the first year after HT; No-AR group (N = 47), including the remaining patients. RESULTS Mean serum IDO activity one month after HT was significantly higher (P = .021) in the AR group (3.32 ± 1.56) than in the no-AR group (2.62 ± 1.35). No significant association between serum IDO activity and gender (male: 3.1 ± 1.56, women: 2.43 ± 0.99, P = .092), recipient age (r = -.07, P = .943) or donor age (r = 0.108, P = 0.293) was observed. By means of binary logistic regression, an odds ratio of 1.4 [CI 95%: 1.033-1.876, P = .03] per unit increase of act-IDO was estimated, with no significant modification upon forced adjustment for age and sex. Mean glomerular filtration rate 1 month after HT was 67.01 ± 28.51 mL/min/m(2). No significant correlation between this parameter and serum IDO activity was observed (r = .160, P = .117). CONCLUSIONS Our study suggests that serum IDO activity one month after HT might be associated with a higher risk of AR during one-year follow-up. This association seems to be independent of recipient gender, age or renal function.
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Increased 3-hydroxykynurenine serum concentrations differentiate Alzheimer's disease patients from controls. Eur Arch Psychiatry Clin Neurosci 2013. [PMID: 23192697 DOI: 10.1007/s00406-012-0384-x] [Citation(s) in RCA: 92] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Increased degradation of tryptophan (TRP) through the kynurenine (KYN) pathway (KP) is known to be involved in the molecular mechanisms resulting in the neuropathogenesis of Alzheimer's disease (AD). Activation of the KP leads to the production of neurotoxic metabolites 3-hydroxykynurenine (3-HK) and quinolinic acid (QUIN) by immune cells and neuroprotective derivates kynurenic acid (KYNA) and picolinic acid (PIC) by astrocytes and neurons. We therefore investigated whether an imbalance between neurotoxic and neuroprotective kynurenine metabolites could be detected in patients with AD. We measured serum levels of TRP, KYNA, 3-HK, PIC and QUIN in 20 patients with AD and for comparison in 20 patients with major depression, and 19 subjectively cognitive impaired subjects. Serum levels of 3-HK were markedly increased in AD patients compared to the comparison groups (p < .0001). Serum levels of the other KP metabolites were not significantly different between groups. Our data indicate an increased production of the neurotoxic KP metabolite 3-HK in AD. In contrast to its downstream metabolites QUIN and PIC, 3-HK can cross the blood-brain barrier via an active transport process. Our data therefore indicate an enhanced availability of 3-HK in the brain of AD patients, which may be related to the previously reported higher production of QUIN in AD brains.
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Bao YS, Ji Y, Zhao SL, Ma LL, Xie RJ, Na SP. Serum levels and activity of indoleamine2,3-dioxygenase and tryptophanyl-tRNA synthetase and their association with disease severity in patients with chronic kidney disease. Biomarkers 2013; 18:379-85. [PMID: 23651343 DOI: 10.3109/1354750x.2013.790074] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVE This study aims to test the serum levels and activity of indoleamine2,3-dioxygenase(IDO) and tryptophanyl-tRNA synthetase (TTS) in patients with chronic kidney disease (CKD) and to evaluate their association with disease severity. METHOD Serum concentrations of IDO and TTS in 61 patients with CKD and 16 healthy volunteers were tested by ELISA. Tryptophan and kynurenine concentrations were measured by high-performance liquid chromatography (HPLC). RESULTS Patients with CKD showed higher serum levels of IDO and TTS in comparison to healthy controls (p = 0.001). Patients with CKD showed lower serum levels of tryptophan and higher serum levels of kynurenine in comparison to healthy controls (p < 0.001). The kyn/Trp ratio significantly correlated with the disease severity in CKD patients (r = 0.721; p < 0.001). CONCLUSIONS IDO and TTS may play critical roles in the immune pathogenesis of CKD. The activity of IDO correlated with the disease severity of CKD.
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Affiliation(s)
- Yu-Shi Bao
- Department of Nephrology, The First Affiliated Hospital of Harbin Medical University, Harbin Medical University, Harbin, China
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Monu NR, Frey AB. Myeloid-derived suppressor cells and anti-tumor T cells: a complex relationship. Immunol Invest 2013; 41:595-613. [PMID: 23017137 DOI: 10.3109/08820139.2012.673191] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Myeloid-Derived Suppressor Cells (MDSC) are immature myeloid cells that are potent inhibitors of immune cell function and which accumulate under conditions of inflammation, especially cancer. MDSC are suggested to promote the growth of cancer by both enhancement of tumor angiogenesis and metastasis and also inhibition of antitumor immune responses. The presence of deficient and/or defective antitumor adaptive and innate immune responses, coincident with accumulation of MDSC in lymphoid organs and tumor parenchyma, supports the notion of a causal relationship. The potent ability of MDSC to inhibit several components and phases of immune response highlights the likelihood that targeting the inhibitory functions of MDSC may maximize the therapeutic potential of antitumor immunotherapy. In order to guide the rational development of immunotherapeutic strategies that incorporate inhibition of MDSC activity and enzymatic functions, thorough understanding of the role of MDSC in antitumor immune responses is required. In this manuscript we review the multifaceted inhibitory functions of MDSC and consider the role of MDSC-induced inhibition of antitumor T cell effector phase. Support for this research is from NIH R01 CA108573.
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Affiliation(s)
- Ngozi R Monu
- NYU Langone Cancer Institute, New York University Langone School of Medicine, New York, New York 10016, USA
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Mangalam A, Poisson L, Nemutlu E, Datta I, Denic A, Dzeja P, Rodriguez M, Rattan R, Giri S. Profile of Circulatory Metabolites in a Relapsing-remitting Animal Model of Multiple Sclerosis using Global Metabolomics. ACTA ACUST UNITED AC 2013; 4. [PMID: 24273690 DOI: 10.4172/2155-9899.1000150] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Multiple sclerosis (MS) is a chronic inflammatory and demyelinating disease of the CNS. Although, MS is well characterized in terms of the role played by immune cells, cytokines and CNS pathology, nothing is known about the metabolic alterations that occur during the disease process in circulation. Recently, metabolic aberrations have been defined in various disease processes either as contributing to the disease, as potential biomarkers, or as therapeutic targets. Thus in an attempt to define the metabolic alterations that may be associated with MS disease progression, we profiled the plasma metabolites at the chronic phase of disease utilizing relapsing remitting-experimental autoimmune encephalomyelitis (RR-EAE) model in SJL mice. At the chronic phase of the disease (day 45), untargeted global metabolomic profiling of plasma collected from EAE diseased SJL and healthy mice was performed, using a combination of high-throughput liquid-and-gas chromatography with mass spectrometry. A total of 282 metabolites were identified, with significant changes observed in 44 metabolites (32 up-regulated and 12 down-regulated), that mapped to lipid, amino acid, nucleotide and xenobiotic metabolism and distinguished EAE from healthy group (p<0.05, false discovery rate (FDR)<0.23). Mapping the differential metabolite signature to their respective biochemical pathways using the Kyoto Encyclopedia of Genes and Genomics (KEGG) database, we found six major pathways that were significantly altered (containing concerted alterations) or impacted (containing alteration in key junctions). These included bile acid biosynthesis, taurine metabolism, tryptophan and histidine metabolism, linoleic acid and D-arginine metabolism pathways. Overall, this study identified a 44 metabolite signature drawn from various metabolic pathways which correlated well with severity of the EAE disease, suggesting that these metabolic changes could be exploited as (1) biomarkers for EAE/MS progression and (2) to design new treatment paradigms where metabolic interventions could be combined with present and experimental therapeutics to achieve better treatment of MS.
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Affiliation(s)
- Ak Mangalam
- Department of Immunology, Mayo Clinic College of Medicine, Rochester, MN 55905, USA ; Department ofNeurology, Mayo Clinic College of Medicine, Rochester, MN 55905, USA
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Abstract
Various pathologies of the central nervous system (CNS) are accompanied by alterations in tryptophan metabolism. The main metabolic route of tryptophan degradation is the kynurenine pathway; its metabolites are responsible for a broad spectrum of effects, including the endogenous regulation of neuronal excitability and the initiation of immune tolerance. This Review highlights the involvement of the kynurenine system in the pathology of neurodegenerative disorders, pain syndromes and autoimmune diseases through a detailed discussion of its potential implications in Huntington's disease, migraine and multiple sclerosis. The most effective preclinical drug candidates are discussed and attention is paid to currently under-investigated roles of the kynurenine pathway in the CNS, where modulation of kynurenine metabolism might be of therapeutic value.
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Xu J, Wei J, Zhu X, Zhang X, Guan J, Wang J, Yin J, Xiao Y, Zhang Y. Increased plasma indoleamine 2,3-dioxygenase activity and interferon-γ levels correlate with the severity of acute graft-versus-host disease after allogeneic hematopoietic stem cell transplantation. Biol Blood Marrow Transplant 2012; 19:196-201. [PMID: 23089565 DOI: 10.1016/j.bbmt.2012.10.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2012] [Accepted: 10/15/2012] [Indexed: 10/27/2022]
Abstract
Indoleamine 2,3-dioxygenase (IDO) is a rate-limiting enzyme for the tryptophan catabolism that plays an important role in the induction of immune tolerance. To evaluate the expression levels of IDO and interferon (IFN)-γ in patients receiving allogeneic hematopoietic stem cell transplantation (allo-HSCT) and to identify the correlation between IDO activity, IFN-γ, and acute graft-versus-host disease (aGVHD), we measured IDO mRNA expression in peripheral blood mononuclear cells in 89 allo-HSCT patients by reverse transcription-polymerase chain reaction. The IDO activity in plasma was also performed by reverse-phase high-performance liquid chromatography; plasma IFN-γ was detected by a standard enzyme-linked immunosorbent assay. IDO mRNA was detected in 55 of 74 patients (74.32%) with aGVHD. Of patients without aGVHD, only 2 of 26 expressed IDO mRNA (7.69%); none of 8 healthy volunteers was positive for IDO expression. Plasma IDO activity was much higher in aGVHD patients than in those without aGVHD (4.74 ± 3.35 vs 1.79 ± 1.02, respectively; P < .0001) or in healthy control subjects (4.74 ± 3.35 vs 1.77 ± .22; P < .0001). Patients with severe (grade III/IV) aGVHD had much higher IDO activity than those with mild (grade I/II) aGVHD (6.57 ± 3.34 vs 2.46 ± 1.41; P < .0001). Meanwhile, there was a significant increase in plasma IFN-γ level in aGVHD patients (P = .0043). IDO activity decreased after alleviation of aGVHD, whereas fluctuation of plasma IDO was also observed upon the recurrence of aGVHD. Plasma IDO activity was correlated with the level of plasma IFN-γ (r = .8288; P < .0001). Using receiver-operating characteristic curves analysis, the sensitivity and specificity for evaluation of aGVHD were determined. The area under the curve of IDO activity was higher than that of IFN-γ (.852 vs .694) with a sensitivity and specificity for IDO of 81% and 78%, respectively, whereas the sensitivity and specificity for IFN-γ were 41% and 93%, respectively. IDO mRNA was expressed in blood mononuclear cells of patients with aGVHD. Plasma IDO activity was elevated in aGVHD patients and was correlated with the severity of aGVHD. In combination with plasma IFN-γ, IDO activity may represent a potential biomarker for the diagnosis and evaluation of aGVHD after allo-HSCT. Intervention of the IDO pathway may also represent an alternative way to overcome steroid-resistant aGVHD.
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Affiliation(s)
- Jinhuan Xu
- Department of Hematology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
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Pierson E, Simmons SB, Castelli L, Goverman JM. Mechanisms regulating regional localization of inflammation during CNS autoimmunity. Immunol Rev 2012; 248:205-15. [PMID: 22725963 DOI: 10.1111/j.1600-065x.2012.01126.x] [Citation(s) in RCA: 140] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Multiple sclerosis (MS) is a disease of the central nervous system (CNS) characterized by inflammatory, demyelinating lesions localized in the brain and spinal cord. Experimental autoimmune encephalomyelitis (EAE) is an animal model of MS that is induced by activating myelin-specific T cells and exhibits immune cell infiltrates in the CNS similar to those seen in MS. Both MS and EAE exhibit disease heterogeneity, reflecting variations in clinical course and localization of lesions within the CNS. Collectively, the differences seen in MS and EAE suggest that the brain and spinal cord function as unique microenvironments that respond differently to infiltrating immune cells. This review addresses the roles of the cytokines interferon-γ and interleukin-17 in determining the localization of inflammation to the brain or spinal cord in EAE.
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Affiliation(s)
- Emily Pierson
- Department of Immunology, University of Washington, Seattle, WA 98195, USA
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Johnson TS, Munn DH. Host Indoleamine 2,3-Dioxygenase: Contribution to Systemic Acquired Tumor Tolerance. Immunol Invest 2012; 41:765-97. [DOI: 10.3109/08820139.2012.689405] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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Wainwright DA, Balyasnikova IV, Chang AL, Ahmed AU, Moon KS, Auffinger B, Tobias AL, Han Y, Lesniak MS. IDO expression in brain tumors increases the recruitment of regulatory T cells and negatively impacts survival. Clin Cancer Res 2012; 18:6110-21. [PMID: 22932670 DOI: 10.1158/1078-0432.ccr-12-2130] [Citation(s) in RCA: 326] [Impact Index Per Article: 27.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
PURPOSE Glioblastoma multiforme (GBM) is an aggressive adult brain tumor with a poor prognosis. One hallmark of GBM is the accumulation of immunosuppressive and tumor-promoting CD4(+)FoxP3(+)GITR(+) regulatory T cells (Tregs). Here, we investigated the role of indoleamine 2,3 dioxygenase (IDO) in brain tumors and the impact on Treg recruitment. EXPERIMENTAL DESIGN To determine the clinical relevance of IDO expression in brain tumors, we first correlated patient survival to the level of IDO expression from resected glioma specimens. We also used novel orthotopic and transgenic models of glioma to study how IDO affects Tregs. The impact of tumor-derived and peripheral IDO expression on Treg recruitment, GITR expression, and long-term survival was determined. RESULTS Downregulated IDO expression in glioma predicted a significantly better prognosis in patients. Coincidently, both IDO-competent and deficient mice showed a survival advantage bearing IDO-deficient brain tumors, when compared with IDO-competent brain tumors. Moreover, IDO deficiency was associated with a significant decrease in brain-resident Tregs, both in orthotopic and transgenic mouse glioma models. IDO deficiency was also associated with lower GITR expression levels on Tregs. Interestingly, the long-term survival advantage conferred by IDO deficiency was lost in T-cell-deficient mice. CONCLUSIONS These clinical and preclinical data confirm that IDO expression increases the recruitment of immunosuppressive Tregs that lead to tumor outgrowth. In contrast, IDO deficiency decreases Treg recruitment and enhances T-cell-mediated tumor rejection. Thus, the data suggest a critical role for IDO-mediated immunosuppression in glioma and support the continued investigation of IDO-Treg interactions in the context of brain tumors.
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Affiliation(s)
- Derek A Wainwright
- The Brain Tumor Center, The University of Chicago, Chicago, Illinois 60637, USA
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132
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Immunoregulatory molecules are master regulators of inflammation during the immune response. FEBS Lett 2012; 586:2897-2905. [PMID: 22819828 DOI: 10.1016/j.febslet.2012.07.032] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Revised: 07/10/2012] [Accepted: 07/11/2012] [Indexed: 01/22/2023]
Abstract
The balance between pro- and anti-inflammatory signalling is critical to maintain the immune homeostasis under physiological conditions as well as for the control of inflammation in different pathological settings. Recent progress in the signalling pathways that control this balance has led to the development of novel therapeutic agents for diseases characterized by alterations in the activation/suppression of the immune response. Different molecules have a key role in the regulation of the immune system, including the receptors PD-1 (Programmed cell Death 1), CTLA-4 (Cytotoxic T-Lymphocyte Antigen 4) and galectins; or the intracellular enzyme IDO (indoleamine 2,3-dioxygenase). In addition, other molecules as CD69, AhR (Aryl hydrocarbon Receptor), and GADD45 (Growth Arrest and DNA Damage-inducible 45) family members, have emerged as potential targets for the regulation of the activation/suppression balance of immune cells. This review offers a perspective on well-characterized as well as emergent negative immune regulatory molecules in the context of autoimmune inflammatory diseases.
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133
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Kim H, Chen L, Lim G, Sung B, Wang S, McCabe MF, Rusanescu G, Yang L, Tian Y, Mao J. Brain indoleamine 2,3-dioxygenase contributes to the comorbidity of pain and depression. J Clin Invest 2012; 122:2940-54. [PMID: 22751107 DOI: 10.1172/jci61884] [Citation(s) in RCA: 243] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2011] [Accepted: 05/16/2012] [Indexed: 01/10/2023] Open
Abstract
Pain and depression are frequently comorbid disorders, but the mechanism underlying this association is unknown. Here, we report that brain indoleamine 2,3-dioxygenase 1 (IDO1), a rate-limiting enzyme in tryptophan metabolism, plays a key role in this comorbidity. We found that chronic pain in rats induced depressive behavior and IDO1 upregulation in the bilateral hippocampus. Upregulation of IDO1 resulted in the increased kynurenine/tryptophan ratio and decreased serotonin/tryptophan ratio in the bilateral hippocampus. We observed elevated plasma IDO activity in patients with both pain and depression, as well as in rats with anhedonia induced by chronic social stress. Intra-hippocampal administration of IL-6 in rats, in addition to in vitro experiments, demonstrated that IL-6 induces IDO1 expression through the JAK/STAT pathway. Further, either Ido1 gene knockout or pharmacological inhibition of hippocampal IDO1 activity attenuated both nociceptive and depressive behavior. These results reveal an IDO1-mediated regulatory mechanism underlying the comorbidity of pain and depression and suggest a new strategy for the concurrent treatment of both conditions via modulation of brain IDO1 activity.
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Affiliation(s)
- Hyangin Kim
- MGH Center for Translational Pain Research, Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
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134
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Eleftheriadis T, Pissas G, Karioti A, Antoniadi G, Liakopoulos V, Dafopoulou K, Pournaras S, Koukoulis G, Stefanidis I. The Indoleamine 2,3-dioxygenase Inhibitor 1-methyl-tryptophan Suppresses Mitochondrial Function, Induces Aerobic Glycolysis and Decreases Interleukin-10 Production in Human Lymphocytes. Immunol Invest 2012; 41:507-20. [DOI: 10.3109/08820139.2012.682244] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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135
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Abstract
Immunotherapy with dendritic cells (DCs), which have been manipulated ex vivo to become immunogenic or tolerogenic, has been tested in clinical trials for disease therapy. DCs are sentinels of the immune system, which after exposure to antigenic or inflammatory signals and crosstalk with effector CD4(+) T cells express high levels of costimulatory molecules and cytokines. Upregulation of either costimulatory molecules or cytokines promotes immunologic DCs, whereas their downregulation generates tolerogenic DCs (TDCs), which induce T regulatory cells (Tregs) and a state of tolerance. Immunogenic DCs are used for the therapy of infectious diseases such as HIV-1 and cancer, whereas tolerogenic DCs are used in treating various autoimmune diseases and in transplantation. DC vaccination is still at an early stage, and improvements are mainly needed in quality control of monitoring assays to generate clinical-grade DC products and to assess the effect of DC vaccination in future clinical trials. Here, we review the recent work in DC generation and monitoring approaches for DC-based trials with immunogenic or tolerogenic DCs.
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136
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Wraith DC, Nicholson LB. The adaptive immune system in diseases of the central nervous system. J Clin Invest 2012; 122:1172-9. [PMID: 22466659 DOI: 10.1172/jci58648] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Tissues of the CNS, such as the brain, optic nerves, and spinal cord, may be affected by a range of insults including genetic, autoimmune, infectious, or neurodegenerative diseases and cancer. The immune system is involved in the pathogenesis of many of these, either by causing tissue damage or alternatively by responding to disease and contributing to repair. It is clearly vital that cells of the immune system patrol the CNS and protect against infection. However, in contrast to other tissues, damage caused by immune pathology in the CNS can be irreparable. The nervous and immune systems have, therefore, coevolved to permit effective immune surveillance while limiting immune pathology. Here we will consider aspects of adaptive immunity in the CNS and the retina, both in the context of protection from infection as well as cancer and autoimmunity, while focusing on immune responses that compromise health and lead to significant morbidity.
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Affiliation(s)
- David C Wraith
- School of Clinical Sciences, University of Bristol, Bristol, United Kingdom.
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137
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Nasoohi S, Hemmati AA, Moradi F, Ahmadiani A. The γ-secretase blocker DAPT impairs recovery from lipopolysaccharide-induced inflammation in rat brain. Neuroscience 2012; 210:99-109. [PMID: 22445932 DOI: 10.1016/j.neuroscience.2012.02.051] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2012] [Revised: 02/28/2012] [Accepted: 02/29/2012] [Indexed: 11/15/2022]
Abstract
γ-Secretase is an important contributing enzyme in Alzheimer's disease and is therefore an important therapeutic target. However, the impact of γ-secretase inhibition is not well studied in acute neuroinflammation induced by systemic infection. In this study the influence of γ-secretase on the expression of some proinflammatory markers was assessed in the acute phase as well as the subsiding phase of neuroinflammation. Cerebral γ-secretase cleavage activity was measured by a fluorometric assay after lipopolysaccharide (LPS) intraperitoneal administration. Time profiles of TNF-α and COX-II expression were then determined to detect the time points relevant to the maximal inflammatory responses and the subsequent recovery phase. γ-Secretase activity coincident with TNF-α protein expression returned to its basal level till 8-12 h after systemic challenge with low dose LPS while COX-II over expression lasted for 48-72 h later. Pharmacological inhibition of γ-secretase with local or systemic administration of DAPT (N-[N-(3,5-difluorophenacetyl)-l-alanyl]-S-phenylglycine t-butyl ester) was performed to indicate the results on the developmental and sinking phases of inflammatory responses in 6 and 72 h post LPS respectively. Our results demonstrate that both local and systemic modulation of γ-secretase hyper-activity with DAPT increase the duration of TNF-α, COX-II, and NFκB induction. We consistently found mild augmented apoptosis in animals treated with DAPT as determined by measuring cleaved caspase-3 expression and by TUNEL assay 72 h following LPS injection. These results suggest that γ-secretase modulation interferes with certain immune regulatory pathways which may restrict some inflammatory transcription factors such as NFκB.
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Affiliation(s)
- S Nasoohi
- Department of Pharmacology and Toxicology, School of Pharmacy and Physiology Research Center, Ahvaz Jundishapur University of Medical Sciences, Golestan, PO Box 6287, Ahvaz, Iran
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138
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Tolerance to apoptotic cells is regulated by indoleamine 2,3-dioxygenase. Proc Natl Acad Sci U S A 2012; 109:3909-14. [PMID: 22355111 DOI: 10.1073/pnas.1117736109] [Citation(s) in RCA: 143] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Tolerance to self-antigens present in apoptotic cells is critical to maintain immune-homeostasis and prevent systemic autoimmunity. However, mechanisms that sustain self-tolerance are poorly understood. Here we show that systemic administration of apoptotic cells to mice induced splenic expression of the tryptophan catabolizing enzyme indoleamine 2,3-dioxygenase (IDO). IDO expression was confined to the splenic marginal zone and was abrogated by depletion of CD169(+) cells. Pharmacologic inhibition of IDO skewed the immune response to apoptotic cells, resulting in increased proinflammatory cytokine production and increased effector T-cell responses toward apoptotic cell-associated antigens. Presymptomatic lupus-prone MRL(lpr/lpr) mice exhibited abnormal elevated IDO expression in the marginal zone and red pulp and inhibition of IDO markedly accelerated disease progression. Moreover, chronic exposure of IDO-deficient mice to apoptotic cells induced a lupus-like disease with serum autoreactivity to double-stranded DNA associated with renal pathology and increased mortality. Thus, IDO limits innate and adaptive immunity to apoptotic self-antigens and IDO-mediated regulation inhibits inflammatory pathology caused by systemic autoimmune disease.
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139
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The role of kynurenines in the pathomechanism of amyotrophic lateral sclerosis and multiple sclerosis: therapeutic implications. J Neural Transm (Vienna) 2012; 119:225-34. [DOI: 10.1007/s00702-012-0765-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2011] [Accepted: 01/09/2012] [Indexed: 12/14/2022]
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140
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Huang G, Zeng Y, Liang P, Zhou C, Zhao S, Huang X, Wu L, He X. Indoleamine 2,3-dioxygenase (IDO) downregulates the cell surface expression of the CD4 molecule. Int J Mol Sci 2012; 13:10863-10879. [PMID: 23109825 PMCID: PMC3472717 DOI: 10.3390/ijms130910863] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2012] [Revised: 08/20/2012] [Accepted: 08/21/2012] [Indexed: 02/05/2023] Open
Abstract
Indoleamine 2,3-dioxygenase (IDO) has been implicated in preventing the fetus from undergoing maternal T cell-mediated immune responses, yet the mechanism underlying these kinds of IDO-mediated immune responses has not been fully elucidated. Since the CD4 molecule plays a central role in the onset and regulation of antigen-specific immune responses, and T cell is sensitive in the absence of tryptophan, we hypothesize that IDO may reduce cell surface CD4 expression. To test this hypothesis, an adenoviral vector-based construct IDO-EGFP was generated and the effect of IDO-EGFP on CD4 expression was determined on recombinant adenoviral infected C8166 and MT-2 cells, by flow cytometry and/or Western blot analysis. The results revealed a significant downregulation of cell membrane CD4 in pAd-IDOEGFP infected cells when compared to that of mock-infected cells or infection with empty vector pAd-EGFP. Further experiments disclosed that either an addition of tryptophan or IDO inhibitor could partly restore CD4 expression in pAd-IDOEGFP infected C8166 cells. Our findings suggest that downregulation of CD4 by IDO might be one of the mechanisms through which IDO regulates T cell-mediated immune responses.
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Affiliation(s)
- Guanyou Huang
- Reproductive Medicine Center, Affiliated Hospital of Guiyang Medical College, Guiyang 550004, China; E-Mails: (C.Z.); (S.Z.)
- Institute of Tissue Transplantation and Immunology, Jinan University, Guangzhou 510632, China; E-Mails: (Y.Z.); (X.H.); (X.H.)
- Author to whom correspondence should be addressed; E-Mail: ; Tel./Fax: +86-851-6776988
| | - Yaoying Zeng
- Institute of Tissue Transplantation and Immunology, Jinan University, Guangzhou 510632, China; E-Mails: (Y.Z.); (X.H.); (X.H.)
| | - Peiyan Liang
- Peking University Shenzhen Graduate School, Shenzhen 518000, China; E-Mail:
| | - Congrong Zhou
- Reproductive Medicine Center, Affiliated Hospital of Guiyang Medical College, Guiyang 550004, China; E-Mails: (C.Z.); (S.Z.)
| | - Shuyun Zhao
- Reproductive Medicine Center, Affiliated Hospital of Guiyang Medical College, Guiyang 550004, China; E-Mails: (C.Z.); (S.Z.)
| | - Xiuyan Huang
- Institute of Tissue Transplantation and Immunology, Jinan University, Guangzhou 510632, China; E-Mails: (Y.Z.); (X.H.); (X.H.)
| | - Lingfei Wu
- Department of Gastroenterology, Second Affiliated Hospital, Shantou University Medical College, Shantou 515041, China; E-Mail:
| | - Xianhui He
- Institute of Tissue Transplantation and Immunology, Jinan University, Guangzhou 510632, China; E-Mails: (Y.Z.); (X.H.); (X.H.)
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141
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Zhu B, Trikudanathan S, Zozulya AL, Sandoval-Garcia C, Kennedy JK, Atochina O, Norberg T, Castagner B, Seeberger P, Fabry Z, Harn D, Khoury SJ, Guleria I. Immune modulation by Lacto-N-fucopentaose III in experimental autoimmune encephalomyelitis. Clin Immunol 2011; 142:351-61. [PMID: 22264636 DOI: 10.1016/j.clim.2011.12.006] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2011] [Revised: 12/09/2011] [Accepted: 12/10/2011] [Indexed: 01/22/2023]
Abstract
Parasitic infections frequently lead to immune deviation or suppression. However, the application of specific parasitic molecules in regulating autoimmune responses remains to be explored. Here we report on the immune modulatory function of Lacto-N-fucopentaose III (LNFPIII), a schistosome glycan, in an animal model for multiple sclerosis. We found that LNFPIII treatment significantly reduced the severity of experimental autoimmune encephalomyelitis (EAE) and CNS inflammation, and skewed peripheral immune response to a Th2 dominant profile. Inflammatory monocytes (IMCs) purified from LNFPIII-treated mice had increased expression of nitric oxide synthase 2, and mediated T cell suppression. LNFPIII treatment also significantly increased mRNA expression of arginase-1, aldehyde dehydrogenase 1 subfamily A2, indoleamine 2,3-dioxygenase and heme oxygenase 1 in splenic IMCs. Furthermore, LNFPIII treatment significantly reduced trafficking of dendritic cells across brain endothelium in vitro. In summary, our study demonstrates that LNFPIII glycan treatment suppresses EAE by modulating both innate and T cell immune response.
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Affiliation(s)
- Bing Zhu
- Center for Neurologic Diseases, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
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142
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Smeekens SP, Henriet SSV, Gresnigt MS, Joosten LAB, Hermans PWM, Netea MG, Warris A, van de Veerdonk FL. Low interleukin-17A production in response to fungal pathogens in patients with chronic granulomatous disease. J Interferon Cytokine Res 2011; 32:159-68. [PMID: 22191467 DOI: 10.1089/jir.2011.0046] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Patients with chronic granulomatous disease (CGD) cannot produce reactive oxygen species (ROS) due to a genetic defect in the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase system. Dysregulation of the L-tryptophan metabolism in mice with defects in NADPH oxidase, resulting in overproduction of interleukin (IL)-17, has been proposed to link ROS defects with hyperinflammation and susceptibility to pulmonary aspergillosis. In this study, we assessed the L-tryptophan metabolism and cytokine profiles in response to fungal pathogens in CGD patients. Peripheral blood mononuclear cells (PBMCs) from CGD patients showed increased production of IL-6, tumor necrosis factor-α, and interferon-γ upon stimulation with Aspergillus or Candida species, while IL-17A production was strikingly low compared with healthy controls. Indoleamine 2,3-dioxygenase expression was similar in PBMCs and neutrophils from CGD patients compared with healthy controls. Conversion of L-tryptophan to L-kynurenine, as measured by high-performance liquid chromatography, did not differ between CGD patients and healthy controls. Moreover, adding L-kynurenine to the cell cultures did not suppress fungal-induced IL-17A production. Although PBMCs of CGD patients produced more proinflammatory cytokines after stimulation, IL-17A production was strikingly low in response to fungal pathogens when compared with healthy controls. In addition, cells from CGD patients did not display a defective L-tryptophan metabolism.
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Affiliation(s)
- Sanne P Smeekens
- Department of Medicine, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
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143
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Silk JD, Lakhal S, Laynes R, Vallius L, Karydis I, Marcea C, Boyd CAR, Cerundolo V. IDO induces expression of a novel tryptophan transporter in mouse and human tumor cells. THE JOURNAL OF IMMUNOLOGY 2011; 187:1617-25. [PMID: 21742973 DOI: 10.4049/jimmunol.1000815] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
IDO is the rate-limiting enzyme in the kynurenine pathway, catabolizing tryptophan to kynurenine. Tryptophan depletion by IDO-expressing tumors is a common mechanism of immune evasion inducing regulatory T cells and inhibiting effector T cells. Because mammalian cells cannot synthesize tryptophan, it remains unclear how IDO(+) tumor cells overcome the detrimental effects of local tryptophan depletion. We demonstrate that IDO(+) tumor cells express a novel amino acid transporter, which accounts for ∼50% of the tryptophan uptake. The induced transporter is biochemically distinguished from the constitutively expressed tryptophan transporter System L by increased resistance to inhibitors of System L, resistance to inhibition by high concentrations of most amino acids tested, and high substrate specificity for tryptophan. Under conditions of low extracellular tryptophan, expression of this novel transporter significantly increases tryptophan entry into IDO(+) tumors relative to tryptophan uptake through the low-affinity System L alone, and further decreases tryptophan levels in the microenvironment. Targeting this additional tryptophan transporter could be a way of pharmacological inhibition of IDO-mediated tumor escape. These findings highlight the ability of IDO-expressing tumor cells to thrive in a tryptophan-depleted microenvironment by expressing a novel, highly tryptophan-specific transporter, which is resistant to inhibition by most other amino acids. The additional transporter allows tumor cells to strike the ideal balance between supply of tryptophan essential for their own proliferation and survival, and depleting the extracellular milieu of tryptophan to inhibit T cell proliferation.
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Affiliation(s)
- Jonathan D Silk
- Medical Research Council Human Immunology Unit, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, Headington OX3 9DS, United Kingdom
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144
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Maes M, Leonard BE, Myint AM, Kubera M, Verkerk R. The new '5-HT' hypothesis of depression: cell-mediated immune activation induces indoleamine 2,3-dioxygenase, which leads to lower plasma tryptophan and an increased synthesis of detrimental tryptophan catabolites (TRYCATs), both of which contribute to the onset of depression. Prog Neuropsychopharmacol Biol Psychiatry 2011; 35:702-21. [PMID: 21185346 DOI: 10.1016/j.pnpbp.2010.12.017] [Citation(s) in RCA: 475] [Impact Index Per Article: 36.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2010] [Revised: 12/07/2010] [Accepted: 12/16/2010] [Indexed: 02/07/2023]
Abstract
This paper reviews the body of evidence that not only tryptophan and consequent 5-HT depletion, but also induction of indoleamine 2,3-dioxygenase (IDO) and the detrimental effects of tryptophan catabolites (TRYCATs) play a role in the pathophysiology of depression. IDO is induced by interferon (IFN)γ, interleukin-6 and tumor necrosis factor-α, lipopolysaccharides and oxidative stress, factors that play a role in the pathophysiology of depression. TRYCATs, like kynurenine and quinolinic acid, are depressogenic and anxiogenic; activate oxidative pathways; cause mitochondrial dysfunctions; and have neuroexcitatory and neurotoxic effects that may lead to neurodegeneration. The TRYCAT pathway is also activated following induction of tryptophan 2,3-dioxygenase (TDO) by glucocorticoids, which are elevated in depression. There is evidence that activation of IDO reduces plasma tryptophan and increases TRYCAT synthesis in depressive states and that TDO activation may play a role as well. The development of depressive symptoms during IFNα-based immunotherapy is strongly associated with IDO activation, increased production of detrimental TRYCATs and lowered levels of tryptophan. Women show greater IDO activation and TRYCAT production following immune challenge than men. In the early puerperium, IDO activation and TRYCAT production are associated with the development of affective symptoms. Clinical depression is accompanied by lowered levels of neuroprotective TRYCATs or increased levels or neurotoxic TRYCATs, and lowered plasma tryptophan, which is associated with indices of immune activation and glucocorticoid hypersecretion. Lowered tryptophan and increased TRYCATs induce T cell unresponsiveness and therefore may exert a negative feedback on the primary inflammatory response in depression. It is concluded that activation of the TRYCAT pathway by IDO and TDO may be associated with the development of depressive symptoms through tryptophan depletion and the detrimental effects of TRYCATs. Therefore, the TRYCAT pathway should be a new drug target in depression. Direct inhibitors of IDO are less likely to be useful drugs than agents, such as kynurenine hydroxylase inhibitors; drugs which block the primary immune response; compounds that increase the protective effects of kynurenic acid; and specific antioxidants that target IDO activation, the immune and oxidative pathways, and 5-HT as well.
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Affiliation(s)
- M Maes
- Maes Clinics @ TRIA, Piyavate Hospital, 998 Rimklongsamsen Road, Bangkok 10310, Thailand.
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145
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Liimatainen S, Lehtimäki K, Raitala A, Peltola M, Oja SS, Peltola J, Hurme MA. Increased indoleamine 2,3-dioxygenase (IDO) activity in idiopathic generalized epilepsy. Epilepsy Res 2011; 94:206-12. [PMID: 21377330 DOI: 10.1016/j.eplepsyres.2011.02.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2010] [Revised: 01/25/2011] [Accepted: 02/06/2011] [Indexed: 11/17/2022]
Abstract
PURPOSE Indoleamine 2,3-dioxygenase (IDO) is a cytokine-inducible enzyme that participates in tryptophan (trp) and serotonin metabolism with an ability to modulate neuroinflammation. Several recent studies have shown associations between cytokines and epilepsy. In this study we investigated whether activation of IDO is associated with epilepsy. METHODS Kynurenine (kyn)/trp serum ratio, as an indicator of IDO activity was analyzed in 271 carefully classified epilepsy patients, and 309 healthy adults. RESULTS IDO activity was increased in patients with unclassified idiopathic generalized epilepsy (IGE) (n=11; p=0.05), in juvenile myoclonic epilepsy (JME) (n=25; p=0.04) and in patients those with temporal lobe epilepsy but no hippocampal sclerosis (TLE-HS) (n=103; p=0.05) compared to the control subjects. In patients with idiopathic (but not cryptogenic or symptomatic) etiology of epilepsy, IDO activity was increased compared to the control subjects (p<0.05). Patients with extra-TLE or TLE+HS had IDO activity comparable to the control subjects. Patients who were one-month seizure-free prior to sampling had increased IDO activity compared to the control subjects (p=0.03). CONCLUSIONS Increased IDO activity appeared to be associated with idiopathic generalized epilepsies such as unclassified IGE and JME, two of the most common types of primary generalized epilepsy. We also found a trend of increased IDO activity in patients with TLE-HS. Our results suggest that increased IDO activity may represent an adaptive metabolic phenomenon in epilepsy, which may also have a neuroprotective or anticonvulsive role by downregulating neuroinflammation in the brain.
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Affiliation(s)
- Suvi Liimatainen
- Department of Neurology and Rehabilitation, Tampere University Hospital, P.O. Box 2000, 33521 Tampere, Finland; Emergency Department Acuta, Tampere University Hospital, P.O. Box 2000, 33521 Tampere, Finland
| | - Kai Lehtimäki
- Department of Neurosurgery, Tampere University Hospital, P.O. Box 2000, 33521 Tampere, Finland
| | - Annika Raitala
- Department of Microbiology and Immunology, University of Tampere, Medical School, 33014 Tampere, Finland
| | - Maria Peltola
- Department of Neurology and Rehabilitation, Tampere University Hospital, P.O. Box 2000, 33521 Tampere, Finland
| | - Simo S Oja
- Department of Paediatrics, Tampere University Hospital, P.O. Box 2000, 33521 Tampere, Finland
| | - Jukka Peltola
- Department of Neurology and Rehabilitation, Tampere University Hospital, P.O. Box 2000, 33521 Tampere, Finland
| | - Mikko A Hurme
- Department of Microbiology and Immunology, University of Tampere, Medical School, 33014 Tampere, Finland; The Laboratory Centre, Tampere University Hospital, P.O. Box 2000, 33521 Tampere, Finland
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146
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Croitoru-Lamoury J, Lamoury FMJ, Caristo M, Suzuki K, Walker D, Takikawa O, Taylor R, Brew BJ. Interferon-γ regulates the proliferation and differentiation of mesenchymal stem cells via activation of indoleamine 2,3 dioxygenase (IDO). PLoS One 2011; 6:e14698. [PMID: 21359206 PMCID: PMC3040184 DOI: 10.1371/journal.pone.0014698] [Citation(s) in RCA: 171] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2010] [Accepted: 01/13/2011] [Indexed: 12/15/2022] Open
Abstract
The kynurenine pathway (KP) of tryptophan metabolism is linked to antimicrobial activity and modulation of immune responses but its role in stem cell biology is unknown. We show that human and mouse mesenchymal and neural stem cells (MSCs and NSCs) express the complete KP, including indoleamine 2,3 dioxygenase 1 (IDO) and IDO2, that it is highly regulated by type I (IFN-β) and II interferons (IFN-γ), and that its transcriptional modulation depends on the type of interferon, cell type and species. IFN-γ inhibited proliferation and altered human and mouse MSC neural, adipocytic and osteocytic differentiation via the activation of IDO. A functional KP present in MSCs, NSCs and perhaps other stem cell types offers novel therapeutic opportunities for optimisation of stem cell proliferation and differentiation.
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147
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Joe AW, Gregory-Evans K. Mesenchymal stem cells and potential applications in treating ocular disease. Curr Eye Res 2011; 35:941-52. [PMID: 20958182 DOI: 10.3109/02713683.2010.516466] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Mesenchymal stem cells (MSCs) are remarkable in stem cell biology. Not only do they have significant tissue regeneration potential, but more recently their paracrine effects (either innate or through genetic augmentation) have become increasingly recognized as useful therapeutic approaches. In particular, clinical roles for MSC therapy in neuroprotection and immune suppression are likely to emerge. These therapeutic effects will be particularly advantageous in work on neurological tissues, because MSC-based molecular therapy could overcome some of the difficulties of long-term drug delivery to tissues, such as the eye, which are relatively inaccessible to systemic delivery (for example due to the blood retina barrier). MSC therapy is, therefore, poised for significant impact in ocular molecular therapeutics, particularly for chronic diseases, such as retinal degeneration, glaucoma, and uveitis. Other molecular and tissue regeneration effects of MSCs are also likely to have impact in the management of ocular surface disease and oculoplastics.
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Affiliation(s)
- Aaron W Joe
- Department of Ophthalmology and Visual Science, University of British Columbia, Vancouver, BC, Canada
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148
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Primary murine microglia are resistant to nitric oxide inhibition of indoleamine 2,3-dioxygenase. Brain Behav Immun 2010; 24:1249-53. [PMID: 20451602 PMCID: PMC2948631 DOI: 10.1016/j.bbi.2010.04.015] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2010] [Revised: 04/30/2010] [Accepted: 04/30/2010] [Indexed: 01/03/2023] Open
Abstract
Indoleamine 2,3-dioxygenase (IDO) is an intracellular heme-containing enzyme that is activated by proinflammatory cytokines, including interferon-γ (IFNγ), and metabolizes tryptophan along the kynurenine pathway. Activation of murine macrophages induces not only IDO but also nitric oxide synthase (iNOS), and the ensuing production of nitric oxide (NO) inhibits IDO. To determine the sensitivity of primary cultures of murine microglia to NO, microglia were stimulated with recombinant murine IFNγ (1 ng/ml) and lipopolysaccharide (LPS) (10 ng/ml). This combination of IFNγ+LPS synergized to produce maximal amounts of nitrite as early as 16h. Steady-state mRNAs for both iNOS and IDO were significantly increased by IFNγ+LPS at 4h post-treatment, followed by an increase in IDO enzymatic activity at 24h. Murine microglia (>95% CD11b(+)) were pretreated with the iNOS inhibitor, L-NIL hydrochloride, at a dose (30 μM) that completely abrogated production of nitrite. L-NIL had no effect on IDO mRNA at 4h or IDO enzymatic activity at 24h following stimulation with IFNγ+LPS. These data establish that IDO regulation in murine microglia is not restrained by NO, thereby permitting the accumulation of kynurenine and its downstream metabolites in the central nervous system.
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149
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Yan Y, Zhang GX, Gran B, Fallarino F, Yu S, Li H, Cullimore ML, Rostami A, Xu H. IDO upregulates regulatory T cells via tryptophan catabolite and suppresses encephalitogenic T cell responses in experimental autoimmune encephalomyelitis. THE JOURNAL OF IMMUNOLOGY 2010; 185:5953-61. [PMID: 20944000 DOI: 10.4049/jimmunol.1001628] [Citation(s) in RCA: 268] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Experimental autoimmune encephalomyelitis (EAE) is a Th1 and Th17 cell-mediated autoimmune disease of the CNS. IDO and tryptophan metabolites have inhibitory effects on Th1 cells in EAE. For Th17 cells, IDO-mediated tryptophan deprivation and small molecule halofuginone-induced amino acid starvation response were shown to activate general control nonrepressed 2 (GCN2) kinase that directly or indirectly inhibits Th17 cell differentiation. However, it remains unclear whether IDO and tryptophan metabolites impact the Th17 cell response by mechanisms other than the GCN2 kinase pathway. In this article, we show that IDO-deficient mice develop exacerbated EAE with enhanced encephalitogenic Th1 and Th17 cell responses and reduced regulatory T cell (Treg) responses. Administration of the downstream tryptophan metabolite 3-hydroxyanthranillic acid (3-HAA) enhanced the percentage of Tregs, inhibited Th1 and Th17 cells, and ameliorated EAE. We further demonstrate that Th17 cells are less sensitive to direct suppression by 3-HAA than are Th1 cells. 3-HAA treatment in vitro reduced IL-6 production by activated spleen cells and increased expression of TGF-β in dendritic cells (DCs), which correlated with enhanced levels of Tregs, suggesting that 3-HAA-induced Tregs contribute to inhibition of Th17 cells. By using a DC-T cell coculture, we found that 3-HAA-treated DCs expressed higher levels of TGF-β and had properties to induce generation of Tregs from anti-CD3/anti-CD28-stimulated naive CD4(+) T cells. Thus, our data support the hypothesis that IDO induces the generation of Tregs via tryptophan metabolites, such as 3-HAA, which enhances TGF-β expression from DCs and promotes Treg differentiation.
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Affiliation(s)
- Yaping Yan
- Department of Neurology, Thomas Jefferson University, Philadelphia, PA 19107, USA
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150
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Lanz TV, Opitz CA, Ho PP, Agrawal A, Lutz C, Weller M, Mellor AL, Steinman L, Wick W, Platten M. Mouse mesenchymal stem cells suppress antigen-specific TH cell immunity independent of indoleamine 2,3-dioxygenase 1 (IDO1). Stem Cells Dev 2010; 19:657-68. [PMID: 19886804 DOI: 10.1089/scd.2009.0385] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Due to their immunosuppressive properties, human mesenchymal stem cells (hMSC) represent a promising tool for cell-based therapies of autoimmune diseases such as multiple sclerosis (MS). Mouse MSC (mMSC) have been used extensively to characterize and optimize route of administration, motility, cellular targets, and immunosuppressive mechanisms in mouse models of autoimmune diseases, such as experimental autoimmune encephalomyelitis (EAE). Tryptophan (trp) catabolism by indolamine-2,3-dioxygenase 1 (IDO1) is a chief endogenous metabolic pathway that tightly regulates unwanted immune responses through depletion of trp and generation of immunosuppressive kynurenines (kyn). IDO1 activity contributes to the immunosuppressive phenotype of hMSC. Here, we demonstrate that although IDO1 is inducible in bone marrow-derived mMSC by proinflammatory stimuli such as interferon-g (IFN-g) and ligands of toll-like receptors (TLR), it does not lead to catabolism of trp in vitro. This failure to catabolize trp is not due to defective TLR signaling as demonstrated by induction of interleukin 6 (IL-6) by TLR activation. While mMSC suppressed the activation of antigen-specific myelin oligodendrocyte glycoprotein (MOG)-reactive T-cell receptor (TCR) transgenic T-helper (TH) cells in co-culture, neither pharmacologic inhibition nor genetic ablation of IDO1 reversed this suppressive effect. Finally, systemic administration of both, IDO1-proficient and phenotypically identical IDO1-deficient mMSC, equally resulted in amelioration of EAE. mMSC, unlike hMSC, do not display IDO1-mediated suppression of antigen-specific T-cell responses.
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Affiliation(s)
- Tobias V Lanz
- Department of Neurooncology, University Hospital of Heidelberg , German Cancer Research Center, Heidelberg, Germany
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