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Niekamp P, Kim CH. Microbial Metabolite Dysbiosis and Colorectal Cancer. Gut Liver 2023; 17:190-203. [PMID: 36632785 PMCID: PMC10018301 DOI: 10.5009/gnl220260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Revised: 08/09/2022] [Accepted: 08/18/2022] [Indexed: 01/13/2023] Open
Abstract
The global burden of colorectal cancer (CRC) is expected to continuously increase. Through research performed in the past decades, the effects of various environmental factors on CRC development have been well identified. Diet, the gut microbiota and their metabolites are key environmental factors that profoundly affect CRC development. Major microbial metabolites with a relevance for CRC prevention and pathogenesis include dietary fiber-derived short-chain fatty acids, bile acid derivatives, indole metabolites, polyamines, trimethylamine-N-oxide, formate, and hydrogen sulfide. These metabolites regulate various cell types in the intestine, leading to an altered intestinal barrier, immunity, chronic inflammation, and tumorigenesis. The physical, chemical, and metabolic properties of these metabolites along with their distinct functions to trigger host receptors appear to largely determine their effects in regulating CRC development. In this review, we will discuss the current advances in our understanding of the major CRC-regulating microbial metabolites, focusing on their production and interactive effects on immune responses and tumorigenesis in the colon.
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Affiliation(s)
- Patrick Niekamp
- Department of Pathology and Mary H. Weiser Food Allergy Center, Rogel Cancer Center, University of Michigan School of Medicine, Ann Arbor, MI, USA
| | - Chang H. Kim
- Department of Pathology and Mary H. Weiser Food Allergy Center, Rogel Cancer Center, University of Michigan School of Medicine, Ann Arbor, MI, USA
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2
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Esmaeili SA, Hajavi J. The role of indoleamine 2,3-dioxygenase in allergic disorders. Mol Biol Rep 2022; 49:3297-3306. [PMID: 35028850 DOI: 10.1007/s11033-021-07067-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 12/08/2021] [Indexed: 01/08/2023]
Abstract
The amino acid tryptophan (TRP) is critical for the expansion and survival of cells. During the past few years, the manipulation of tryptophan metabolism via indoleamine 2,3 dioxygenase (IDO) has been presented as a significant regulatory mechanism for tolerance stimulation and the regulation of immune responses. Currently, a considerable number of studies suggest that the role of IDO in T helper 2 (Th2) cell regulation may be different from that of T helper 1 (Th1) immune responses. IDO acts as an immunosuppressive tolerogenic enzyme to decrease allergic responses through the stimulation of the Kynurenine-IDO pathway, the subsequent reduction of TRP, and the promotion of Kynurenine products. Kynurenine products motivate T-cell apoptosis and anergy, the propagation of Treg and Th17 cells, and the aberration of the Th1/Th2 response. We suggest that the IDO-kynurenine pathway can function as a negative reaction round for Th1 cells; however, it may play a different role in upregulating principal Th2 immune responses. In this review, we intend to integrate novel results on this pathway in correlation with allergic diseases.
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Affiliation(s)
- Seyed-Alireza Esmaeili
- Immunology Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.,Immunology Department, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Jafar Hajavi
- Department of Basic Sciences, Faculty of Medicine, Infectious Diseases Research Center, Gonabad University of Medical Science, 9691793718, Gonabad, Iran.
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3
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Wyatt M, Greathouse KL. Targeting Dietary and Microbial Tryptophan-Indole Metabolism as Therapeutic Approaches to Colon Cancer. Nutrients 2021; 13:1189. [PMID: 33916690 PMCID: PMC8066279 DOI: 10.3390/nu13041189] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 03/29/2021] [Accepted: 03/31/2021] [Indexed: 12/15/2022] Open
Abstract
Tryptophan metabolism, via the kynurenine (Kyn) pathway, and microbial transformation of tryptophan to indolic compounds are fundamental for host health; both of which are altered in colon carcinogenesis. Alterations in tryptophan metabolism begin early in colon carcinogenesis as an adaptive mechanism for the tumor to escape immune surveillance and metastasize. The microbial community is a key part of the tumor microenvironment and influences cancer initiation, promotion and treatment response. A growing awareness of the impact of the microbiome on tryptophan (Trp) metabolism in the context of carcinogenesis has prompted this review. We first compare the different metabolic pathways of Trp under normal cellular physiology to colon carcinogenesis, in both the host cells and the microbiome. Second, we review how the microbiome, specifically indoles, influence host tryptophan pathways under normal and oncogenic metabolism. We conclude by proposing several dietary, microbial and drug therapeutic modalities that can be utilized in combination to abrogate tumorigenesis.
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Affiliation(s)
- Madhur Wyatt
- Human Health, Performance and Recreation, Robbins College of Health and Human Sciences, Baylor University, Waco, TX 76798-7346, USA;
| | - K. Leigh Greathouse
- Human Science and Design, Robbins College of Health and Human Sciences, Baylor University, Waco, TX 76798-7346, USA
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4
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Badawy AB. Immunotherapy of COVID-19 with poly (ADP-ribose) polymerase inhibitors: starting with nicotinamide. Biosci Rep 2020; 40:BSR20202856. [PMID: 33063092 PMCID: PMC7601349 DOI: 10.1042/bsr20202856] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 09/23/2020] [Accepted: 09/28/2020] [Indexed: 12/15/2022] Open
Abstract
COVID-19 induces a proinflammatory environment that is stronger in patients requiring intensive care. The cytokine components of this environment may determine efficacy or otherwise of glucocorticoid therapy. The immunity modulators, the aryl hydrocarbon receptor (AhR) and the nuclear NAD+-consuming enzyme poly (ADP-ribose) polymerase 1 (PARP 1) may play a critical role in COVID-19 pathophysiology. The AhR is overexpressed in coronaviruses, including COVID-19 and, as it regulates PARP gene expression, the latter is likely to be activated in COVID-19. PARP 1 activation leads to cell death mainly by depletion of NAD+ and adenosine triphosphate (ATP), especially when availability of these energy mediators is compromised. PARP expression is enhanced in other lung conditions: the pneumovirus respiratory syncytial virus (RSV) and chronic obstructive pulmonary disease (COPD). I propose that PARP 1 activation is the terminal point in a sequence of events culminating in patient mortality and should be the focus of COVID-19 immunotherapy. Potent PARP 1 inhibitors are undergoing trials in cancer, but a readily available inhibitor, nicotinamide (NAM), which possesses a highly desirable biochemical and activity profile, merits exploration. It conserves NAD+ and prevents ATP depletion by PARP 1 and Sirtuin 1 (silent mating type information regulation 2 homologue 1) inhibition, enhances NAD+ synthesis, and hence that of NADP+ which is a stronger PARP inhibitor, reverses lung injury caused by ischaemia/reperfusion, inhibits proinflammatory cytokines and is effective against HIV infection. These properties qualify NAM for therapeutic use initially in conjunction with standard clinical care or combined with other agents, and subsequently as an adjunct to stronger PARP 1 inhibitors or other drugs.
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Affiliation(s)
- Abdulla A.-B. Badawy
- Formerly School of Health Sciences, Cardiff Metropolitan University, Cardiff, Wales, U.K
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Akram F, Jennings TB, Stiller JW, Lowry CA, Postolache TT. Mood Worsening on Days with High Pollen Counts is associated with a Summer Pattern of Seasonality. Pteridines 2019; 30:133-141. [PMID: 31631951 PMCID: PMC6800045 DOI: 10.1515/pteridines-2019-0016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Background: Summer/spring-type seasonal affective disorder (S-SAD) is the less common subtype of seasonal affective disorder and evidence regarding potential triggers of S-SAD is scarce. Recent reports support association of airborne-pollen with seasonal exacerbation of depression (mood seasonality) and timing of suicidal behavior. Therefore, we hypothesized that Old Order Amish (OOA) with summer/spring pattern of seasonality (abbreviated as summer pattern) and S-SAD will have significant mood worsening on high pollen days. Methods: A seasonal pattern of mood worsening and SAD parameters were estimated using Seasonal Pattern Assessment Questionnaire (SPAQ). Age- and gender-adjusted ANCOVAs and post hoc analyses were conducted to compare mood worsening on days with high pollen counts between summer-pattern vs no-summer-pattern of mood worsening, S-SAD vs no-S-SAD, winter-pattern vs no-winter-pattern of mood worsening, and W-SAD vs no-W-SAD groups. Results: The prevalence of S-SAD was 0.4%, while 4.5% of individuals had a summer pattern of mood seasonality. A statistically significant difference for mood worsening on high pollen days was observed between summer-pattern vs no-summer-pattern of mood worsening (p = 0.006). The significant association between S-SAD vs no-SAD groups (p = 0.032) for mood worsening on high pollen days did not withstand Bonferroni adjustment for multiple comparisons. No significant association was found for winter-pattern vs no-winter-pattern of mood worsening (p = 0.61) and for W-SAD vs no-W-SAD (p = 0.19) groups. Conclusion: Our results are consistent with previous studies implicating links between aeroallergen exposure and summer pattern of seasonality, but not the winter pattern of seasonality.
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Affiliation(s)
- Faisal Akram
- Mood and Anxiety Program, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Tyler B Jennings
- Mood and Anxiety Program, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - John W Stiller
- Mood and Anxiety Program, University of Maryland School of Medicine, Baltimore, MD, 21201, USA
| | - Christopher A Lowry
- Department of Integrative Physiology, Center for Neuroscience, and Center for Microbial Exploration, University of Colorado Boulder, Boulder, CO 80309, USA; Department of Physical Medicine & Rehabilitation, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA; Veterans Health Administration, Rocky Mountain Mental Illness Research Education and Clinical Center (MIRECC), Rocky Mountain Regional Veterans Affairs Medical Center (RMRVAMC), Aurora, CO, 80045, USA; Military and Veteran Microbiome: Consortium for Research and Education (MVM-CoRE), Aurora, CO 80045, USA
| | - Teodor T Postolache
- Mood and Anxiety Program, University of Maryland School of Medicine, Baltimore, MD, 21201, USA; Saint Elizabeths Hospital, Psychiatry Residency Training Program, Washington, DC, 20032, USA; Department of Physical Medicine & Rehabilitation, University of Colorado Anschutz Medical Campus, Aurora, CO 80045, USA; Veterans Health Administration, Rocky Mountain Mental Illness Research Education and Clinical Center (MIRECC), Rocky Mountain Regional Veterans Affairs Medical Center (RMRVAMC), Aurora, CO, 80045, USA; Amish Research Clinic of the University of Maryland, Lancaster, PA, 17602, USA
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6
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Xu K, Bai M, Bin P, Duan Y, Wu X, Liu H, Yin Y. Negative effects on newborn piglets caused by excess dietary tryptophan in the morning in sows. JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE 2019; 99:3005-3016. [PMID: 30478950 DOI: 10.1002/jsfa.9514] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Revised: 11/22/2018] [Accepted: 11/22/2018] [Indexed: 06/09/2023]
Abstract
BACKGROUND This study investigated the effect of dynamic feeding models of dietary tryptophan on sows' performance during late pregnancy. RESULTS The average piglet birth weight and live farrowing rate from sows consuming a high-low tryptophan diet (0.39% Trp in the morning and 0.13% Trp in the afternoon) were decreased compared with those fed a 2×tryptophan diet (0.26% Trp in the morning and afternoon). Compared with the 2×tryptophan group, sow serum kynurenic acid and the newborn liver n-6:n-3 polyunsaturated fatty acid ratio were significantly higher, and sow serum taurine and newborn serum taurine, phosphoserine, cysteine and proline were lower in the high-low tryptophan diet group. Eighty-eight genes were differentially expressed in newborn piglets' livers between the 2×tryptophan and high-low groups. Genes related to cytotoxic effector regulation (major histocompatibility complex class I proteins), NADH oxidation, reactive oxygen species (ROS) metabolism and tissue development were differentially expressed between these two groups. CONCLUSION Together, the results provide information on new biomarkers in serum or liver and provide novel insights into variations in the fetal liver during exogenous stimulus response and biological processes of ROS metabolism in fetuses during late pregnancy caused by a single excessive tryptophan ingestion daily in the morning. © 2018 Society of Chemical Industry.
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Affiliation(s)
- Kang Xu
- Key Laboratory of Agroecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, China
- Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, Changsha, China
- Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South Central, Ministry of Agriculture, Changsha, China
- Hangzhou King Techina Technology Company Academician Expert Workstation, Hangzhou King Techina Technology Co., Ltd., Hangzhou, China
| | - Miaomiao Bai
- Key Laboratory of Agroecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, China
- Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, Changsha, China
- Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South Central, Ministry of Agriculture, Changsha, China
- Hangzhou King Techina Technology Company Academician Expert Workstation, Hangzhou King Techina Technology Co., Ltd., Hangzhou, China
- National Engineering Laboratory for Pollution Control and Waste Utilization in Livestock and Poultry Production, Changsha, China
- College of Animal Science, South China Agricultural University, Guangzhou, China
| | - Peng Bin
- Key Laboratory of Agroecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, China
- Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, Changsha, China
- Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South Central, Ministry of Agriculture, Changsha, China
- Hangzhou King Techina Technology Company Academician Expert Workstation, Hangzhou King Techina Technology Co., Ltd., Hangzhou, China
| | - Yehui Duan
- Key Laboratory of Agroecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, China
- Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, Changsha, China
- Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South Central, Ministry of Agriculture, Changsha, China
- Hangzhou King Techina Technology Company Academician Expert Workstation, Hangzhou King Techina Technology Co., Ltd., Hangzhou, China
| | - Xin Wu
- Key Laboratory of Agroecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, China
- Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, Changsha, China
- Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South Central, Ministry of Agriculture, Changsha, China
- Hangzhou King Techina Technology Company Academician Expert Workstation, Hangzhou King Techina Technology Co., Ltd., Hangzhou, China
| | - Hongnan Liu
- Key Laboratory of Agroecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, China
- Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, Changsha, China
- Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South Central, Ministry of Agriculture, Changsha, China
- Hangzhou King Techina Technology Company Academician Expert Workstation, Hangzhou King Techina Technology Co., Ltd., Hangzhou, China
- National Engineering Laboratory for Pollution Control and Waste Utilization in Livestock and Poultry Production, Changsha, China
- Hunan Co-Innovation Center of Animal Production Safety, CICAPS, Changsha, China
| | - Yulong Yin
- Key Laboratory of Agroecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha, China
- Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, Changsha, China
- Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South Central, Ministry of Agriculture, Changsha, China
- Hangzhou King Techina Technology Company Academician Expert Workstation, Hangzhou King Techina Technology Co., Ltd., Hangzhou, China
- National Engineering Laboratory for Pollution Control and Waste Utilization in Livestock and Poultry Production, Changsha, China
- College of Animal Science, South China Agricultural University, Guangzhou, China
- Guangdong Kondarl Agro-pastoral Technology Co., Ltd., Dongguan, China
- Academician Workstation of Changsha Medical University, Changsha, China
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López-Hernández Y, Herrera-Van Oostdam AS, Toro-Ortiz JC, López JA, Salgado-Bustamante M, Murgu M, Torres-Torres LM. Urinary Metabolites Altered during the Third Trimester in Pregnancies Complicated by Gestational Diabetes Mellitus: Relationship with Potential Upcoming Metabolic Disorders. Int J Mol Sci 2019; 20:ijms20051186. [PMID: 30857174 PMCID: PMC6429483 DOI: 10.3390/ijms20051186] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 02/23/2019] [Accepted: 03/04/2019] [Indexed: 12/22/2022] Open
Abstract
Gestational diabetes mellitus (GDM) is a disorder in pregnancy with highest impact in the future life of both mother and newborn. Increasing incidence, economic impact, and potential for severe GDM-related pregnancy complications are some factors that have motivated the deep study of physiopathology, risk factors for developing GDM, and potential biomarkers for its diagnosis. In the present pilot study, we analyzed the urinary metabolome profile of GDM patients in the 3rd trimester of pregnancy, when GDM is already established and the patients are under dietary and pharmacological control. An untargeted metabolomics method based on liquid chromatography–mass spectrometry analysis was developed to identify differentially expressed metabolites in the GDM group. We identified 14 metabolites that are significantly upregulated in the urine of GDM patients, and, more importantly, we identified those related with the steroid hormone biosynthesis and tryptophan (TRP) metabolism pathways, which are associated with GDM pathophysiology. Thus, these metabolites could be screened as potential prognostic biomarkers of type two diabetes mellitus, coronary artery disease and chronic renal failure in future follow-up studies with GDM patients.
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Affiliation(s)
- Yamilé López-Hernández
- Metabolomics and Proteomics Laboratory, CONACyT-Universidad Autónoma de Zacatecas, 98066 Zacatecas, Mexico.
| | | | - Juan Carlos Toro-Ortiz
- Gynecology and Obstetrics Division, Hospital Central "Dr. Ignacio Morones Prieto",7800 San Luis Potosí, Mexico.
| | - Jesús Adrián López
- MicroRNAs Laboratory, Unidad Académica de Ciencias Biológicas, Universidad Autónoma de Zacatecas, 98066 Zacatecas, Mexico.
| | | | - Michael Murgu
- Waters Technologies of Brazil, 06400 Barueri, Brazil.
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Van der Leek AP, Yanishevsky Y, Kozyrskyj AL. The Kynurenine Pathway As a Novel Link between Allergy and the Gut Microbiome. Front Immunol 2017; 8:1374. [PMID: 29163472 PMCID: PMC5681735 DOI: 10.3389/fimmu.2017.01374] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Accepted: 10/05/2017] [Indexed: 12/17/2022] Open
Abstract
In the past few decades, the indoleamine 2,3 dioxygenase (IDO) subset of the kynurenine (KYN) pathway of tryptophan (TRP) metabolism has been the subject of much research in the area of immune tolerance. In this review, we aim to incorporate new findings on this pathway in relation to allergy and the gut microbiome, while providing a comprehensive overview of the pathway itself. Stimulated by interferon gamma, IDO acts as a tolerogenic, immunosuppressive enzyme to attenuate allergic responses by the induction of the KYN-IDO pathway, resultant depletion of TRP, and elevation in KYN metabolites. Acting through the aryl hydrocarbon receptor, KYN metabolites cause T-cell anergy and apoptosis, proliferation of Treg and Th17 cells, and deviation of the Th1/Th2 response, although the outcome is highly dependent on the microenvironment. Moreover, new evidence from germ-free mice and human infants shows that gut microbiota and breast milk are key in determining the functioning of the KYN-IDO pathway. As such, we recommend further research on how this pathway may be a critical link between the microbiome and development of allergy.
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Affiliation(s)
| | | | - Anita L Kozyrskyj
- Department of Pediatrics, University of Alberta, Edmonton, AB, Canada.,Department of Obstetrics and Gynecology, University of Alberta, Edmonton, AB, Canada.,Department of Public Health Sciences, University of Alberta, Edmonton, AB, Canada
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9
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Koch S, Stroisch TJ, Vorac J, Herrmann N, Leib N, Schnautz S, Kirins H, Förster I, Weighardt H, Bieber T. AhR mediates an anti-inflammatory feedback mechanism in human Langerhans cells involving FcεRI and IDO. Allergy 2017; 72:1686-1693. [PMID: 28376268 DOI: 10.1111/all.13170] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/27/2017] [Indexed: 12/29/2022]
Abstract
BACKGROUND Aryl hydrocarbon receptor (AhR), an important regulator of immune responses, is activated by UVB irradiation in the skin. Langerhans cells (LC) in the epidermis of patients with atopic dermatitis (AD) carry the high-affinity receptor for IgE, FcεRI, and are crucially involved in the pathogenesis of AD by inducing inflammatory responses and regulating tolerogenic processes. OBJECTIVES We investigated AhR and AhR repressor (AhRR) expression and functional consequences of AhR activation in human ex vivo skin cells and in in vitro-generated LC. METHODS Epidermal cells from healthy skin were analyzed for their expression of AhR and AhRR. LC generated from CD34+ hematopoietic stem cells (CD34LC) were treated with the UV photoproduct and AhR ligand 6-formylindolo[3,2-b]carbazole (FICZ). Cell surface receptors, transcription factors, and the tolerogenic tryptophan-degrading enzyme indoleamine 2,3-dioxygenase (IDO) were analyzed using flow cytometry and quantitative PCR. RESULTS Epidermal LC and CD34LC express AhR and AhRR. AhR was also found in keratinocytes, which lack AhRR. AhR activation of LC by FICZ caused downregulation of FcεRI in CD34LC without affecting their maturation. AhR-mediated regulation of FcεRI did not involve any known transcription factors related to this receptor. Furthermore, we could show upregulation of IDO mediated by AhR engagement. CONCLUSIONS Our study shows that AhR activation by FICZ reduces FcεRI and upregulates IDO expression in LC. This AhR-mediated anti-inflammatory feedback mechanism may dampen the allergen-induced inflammation in AD.
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Affiliation(s)
- S. Koch
- Department of Dermatology and AllergyChristine Kühne ‐ Center for Allergy Research and Education (CK‐CARE)University of BonnBonnGermany
| | - T. J. Stroisch
- Department of Dermatology and AllergyChristine Kühne ‐ Center for Allergy Research and Education (CK‐CARE)University of BonnBonnGermany
| | - J. Vorac
- LIMES Institute, Immunology and EnvironmentUniversity of BonnBonnGermany
| | - N. Herrmann
- Department of Dermatology and AllergyChristine Kühne ‐ Center for Allergy Research and Education (CK‐CARE)University of BonnBonnGermany
| | - N. Leib
- Department of Dermatology and AllergyChristine Kühne ‐ Center for Allergy Research and Education (CK‐CARE)University of BonnBonnGermany
| | - S. Schnautz
- Department of Dermatology and AllergyChristine Kühne ‐ Center for Allergy Research and Education (CK‐CARE)University of BonnBonnGermany
| | - H. Kirins
- Department of Dermatology and AllergyChristine Kühne ‐ Center for Allergy Research and Education (CK‐CARE)University of BonnBonnGermany
| | - I. Förster
- LIMES Institute, Immunology and EnvironmentUniversity of BonnBonnGermany
| | - H. Weighardt
- LIMES Institute, Immunology and EnvironmentUniversity of BonnBonnGermany
- Innate Immunity and Extrinsic Skin AgingIUF ‐ Leibniz Research Institute for Environmental MedicineDüsseldorfGermany
| | - T. Bieber
- Department of Dermatology and AllergyChristine Kühne ‐ Center for Allergy Research and Education (CK‐CARE)University of BonnBonnGermany
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10
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Súkeníková L, Černý V, Novotná O, Petrásková P, Boráková K, Kolářová L, Prokešová L, Hrdý J. Different capacity of in vitro generated myeloid dendritic cells of newborns of healthy and allergic mothers to respond to probiotic strain E. coli O83:K24:H31. Immunol Lett 2017; 189:82-89. [PMID: 28554713 DOI: 10.1016/j.imlet.2017.05.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 05/19/2017] [Accepted: 05/23/2017] [Indexed: 10/19/2022]
Abstract
Allergic diseases belong to one of the most common diseases with steadily increasing incidence even among young children. There is an urgent need to identify a prognostic marker pointing to increased risk of allergy development enabling early preventive measures introduction. It has been shown that administration of selected probiotic strains or mixtures could prevent allergy development. In our study, we have tested the capacity of probiotic strain Escherichia coli O83:K24:H31 (E. coli O83) to promote dendritic cell (DC) maturation and polarisation of immune responses. Increased presence of activation marker CD83 was observed on DC stimulated by E. coli O83 and DC of newborns of allergic mothers have significantly more increased cell surface presence of CD83 in comparison to children of healthy mothers. Increased gene expression and secretion of IL-10 was detected in DC stimulated with E. coli O83 being higher in DC of newborns of healthy mothers in comparison to allergic ones. Generally, increased presence of intracellular cytokines (IL-4, IL-13, IFN-gamma, IL-17A, IL-22, IL-10) was detected in CD4+ T cells cocultured with DC of children of allergic mothers in comparison to healthy ones. E. coli O83 primed DC significantly increased IL-10 and IL-17A in CD4 T cells of newborns of healthy mothers in comparison to the levels detected in CD4 T cells cocultured with control non-stimulated DC. We can conclude E. coli O83 induces dendritic cell maturation and IL-10 production in DC. Newborns of allergic mothers have generally increased reactivity of both DC and CD4 T cells which together with decreased capacity of DC of newborns of allergic mothers to produce IL-10 could support inappropriate immune responses development after allergen encounter.
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Affiliation(s)
- Lenka Súkeníková
- Institute of Immunology and Microbiology, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic
| | - Viktor Černý
- Institute of Immunology and Microbiology, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic
| | - Olga Novotná
- Institute of Immunology and Microbiology, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic
| | - Petra Petrásková
- Institute of Immunology and Microbiology, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic
| | | | - Libuše Kolářová
- Institute of Immunology and Microbiology, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic
| | - Ludmila Prokešová
- Institute of Immunology and Microbiology, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic
| | - Jiří Hrdý
- Institute of Immunology and Microbiology, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic.
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11
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Xu K, Liu H, Bai M, Gao J, Wu X, Yin Y. Redox Properties of Tryptophan Metabolism and the Concept of Tryptophan Use in Pregnancy. Int J Mol Sci 2017; 18:E1595. [PMID: 28737706 PMCID: PMC5536082 DOI: 10.3390/ijms18071595] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Revised: 07/11/2017] [Accepted: 07/19/2017] [Indexed: 12/30/2022] Open
Abstract
During pregnancy, tryptophan (Trp) is required for several purposes, and Trp metabolism varies over time in the mother and fetus. Increased oxidative stress (OS) with high metabolic, energy and oxygen demands during normal pregnancy or in pregnancy-associated disorders has been reported. Taking the antioxidant properties of Trp and its metabolites into consideration, we made four hypotheses. First, the use of Trp and its metabolites is optional based on their antioxidant properties during pregnancy. Second, dynamic Trp metabolism is an accommodation mechanism in response to OS. Third, regulation of Trp metabolism could be used to control/attenuate OS according to variations in Trp metabolism during pregnancy. Fourth, OS-mediated injury could be alleviated by regulation of Trp metabolism in pregnancy-associated disorders. Future studies in normal/abnormal pregnancies and in associated disorders should include measurements of free Trp, total Trp, Trp metabolites, and activities of Trp-degrading enzymes in plasma. Abnormal pregnancies and some associated disorders may be associated with disordered Trp metabolism related to OS. Mounting evidence suggests that the investigation of the use of Trp and its metabolites in pregnancy will be meanful.
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Affiliation(s)
- Kang Xu
- Chinese Academy of Sciences, Institute of Subtropical Agriculture, Key Laboratory of Agroecological Processes in Subtropical Region, Changsha 410125, China.
- National Engineering Laboratory for Pollution Control and Waste Utilization in Livestock and Poultry Production, Changsha 410125, China.
- Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, Changsha 410125, China.
- Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South Central, Ministry of Agriculture, Changsha 410125, China.
| | - Hongnan Liu
- Chinese Academy of Sciences, Institute of Subtropical Agriculture, Key Laboratory of Agroecological Processes in Subtropical Region, Changsha 410125, China.
- National Engineering Laboratory for Pollution Control and Waste Utilization in Livestock and Poultry Production, Changsha 410125, China.
- Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, Changsha 410125, China.
- Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South Central, Ministry of Agriculture, Changsha 410125, China.
| | - Miaomiao Bai
- Chinese Academy of Sciences, Institute of Subtropical Agriculture, Key Laboratory of Agroecological Processes in Subtropical Region, Changsha 410125, China.
- National Engineering Laboratory for Pollution Control and Waste Utilization in Livestock and Poultry Production, Changsha 410125, China.
- Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, Changsha 410125, China.
- Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South Central, Ministry of Agriculture, Changsha 410125, China.
| | - Jing Gao
- Chinese Academy of Sciences, Institute of Subtropical Agriculture, Key Laboratory of Agroecological Processes in Subtropical Region, Changsha 410125, China.
- National Engineering Laboratory for Pollution Control and Waste Utilization in Livestock and Poultry Production, Changsha 410125, China.
- Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, Changsha 410125, China.
- Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South Central, Ministry of Agriculture, Changsha 410125, China.
| | - Xin Wu
- Chinese Academy of Sciences, Institute of Subtropical Agriculture, Key Laboratory of Agroecological Processes in Subtropical Region, Changsha 410125, China.
- National Engineering Laboratory for Pollution Control and Waste Utilization in Livestock and Poultry Production, Changsha 410125, China.
- Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, Changsha 410125, China.
- Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South Central, Ministry of Agriculture, Changsha 410125, China.
| | - Yulong Yin
- Chinese Academy of Sciences, Institute of Subtropical Agriculture, Key Laboratory of Agroecological Processes in Subtropical Region, Changsha 410125, China.
- National Engineering Laboratory for Pollution Control and Waste Utilization in Livestock and Poultry Production, Changsha 410125, China.
- Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry Production, Changsha 410125, China.
- Scientific Observing and Experimental Station of Animal Nutrition and Feed Science in South Central, Ministry of Agriculture, Changsha 410125, China.
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The end of the road for the tryptophan depletion concept in pregnancy and infection. Clin Sci (Lond) 2017; 130:1327-33. [PMID: 27358028 PMCID: PMC4926258 DOI: 10.1042/cs20160153] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Accepted: 03/16/2016] [Indexed: 12/19/2022]
Abstract
We hypothesize that: (1) L-tryptophan (Trp) is greatly utilized and not depleted in pregnancy; (2) fetal tolerance is achieved in part through immunosuppressive kynurenine (Kyn) metabolites produced by the flux of plasma free (non-albumin-bound) Trp down the Kyn pathway; (3) the role of indoleamine 2,3-dioxygenase (IDO) in infection is not related to limitation of an essential amino acid, but is rather associated with stress responses and the production of Kyn metabolites that regulate the activities of antigen presenting cells and T-cells, as well as increased NAD+ synthesis in IDO-expressing cells; (4) Trp depletion is not a host defence mechanism, but is a consequence of Trp utilization. We recommend that future studies in normal and abnormal pregnancies and in patients with infections or cancer should include measurements of plasma free Trp, determinants of Trp binding (albumin and non-esterified fatty acids), total Trp, determinants of activities of the Trp-degrading enzymes Trp 2,3-dioxygenase (TDO) (cortisol) and IDO (cytokines) and levels of Kyn metabolites. We also hypothesize that abnormal pregnancies and failure to combat infections or cancer may be associated with excessive Trp metabolism that can lead to pathological immunosuppression by excessive production of Kyn metabolites. Mounting evidence from many laboratories indicates that Trp metabolites are key regulators of immune cell behaviour, whereas Trp depletion is an indicator of extensive utilization of this key amino acid.
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Oettgen HC. Fifty years later: Emerging functions of IgE antibodies in host defense, immune regulation, and allergic diseases. J Allergy Clin Immunol 2017; 137:1631-1645. [PMID: 27263999 DOI: 10.1016/j.jaci.2016.04.009] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Revised: 04/22/2016] [Accepted: 04/22/2016] [Indexed: 01/15/2023]
Abstract
Fifty years ago, after a long search, IgE emerged as the circulating factor responsible for triggering allergic reactions. Its extremely low concentration in plasma created significant hurdles for scientists working to reveal its identity. We now know that IgE levels are invariably increased in patients affected by atopic conditions and that IgE provides the critical link between the antigen recognition role of the adaptive immune system and the effector functions of mast cells and basophils at mucosal and cutaneous sites of environmental exposure. This review discusses the established mechanisms of action of IgE in pathologic immediate hypersensitivity, as well as its multifaceted roles in protective immunity, control of mast cell homeostasis, and its more recently revealed immunomodulatory functions.
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Affiliation(s)
- Hans C Oettgen
- Division of Immunology, Boston Children's Hospital, and the Department of Pediatrics, Harvard Medical School, Boston, Mass.
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Badawy AAB. Tryptophan availability for kynurenine pathway metabolism across the life span: Control mechanisms and focus on aging, exercise, diet and nutritional supplements. Neuropharmacology 2017; 112:248-263. [DOI: 10.1016/j.neuropharm.2015.11.015] [Citation(s) in RCA: 100] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Revised: 11/15/2015] [Accepted: 11/18/2015] [Indexed: 10/22/2022]
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Buyuktiryaki B, Sahiner UM, Girgin G, Birben E, Soyer OU, Cavkaytar O, Cetin C, Arik Yilmaz E, Yavuz ST, Kalayci O, Baydar T, Sackesen C. Low indoleamine 2,3-dioxygenase activity in persistent food allergy in children. Allergy 2016; 71:258-66. [PMID: 26449488 DOI: 10.1111/all.12785] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/04/2015] [Indexed: 01/14/2023]
Abstract
BACKGROUND Indoleamine 2,3-dioxygenase (IDO), which degrades tryptophan (Trp) to kynurenine (Kyn), has been demonstrated to contribute to modulation of allergic responses. However, the role of IDO in food allergy has not yet been elucidated. METHODS Serum Trp and Kyn concentrations were analyzed by high-pressure liquid chromatography. Expression of IDO gene was measured by real-time PCR. The levels of interleukin (IL)-4, IL-10, and interferon (IFN)-γ in cell culture supernatants were measured by ELISA. RESULTS Kyn/Trp (IDO activity) was significantly lower in subjects with food allergy (n = 100) than in aged-matched healthy controls (n = 112) (P = 0.004). Kyn/Trp was decreased from healthy through completely tolerant, partially tolerant, and reactive ones [LN transformation (mean ± SEM) healthy: 3.9 ± 0.02 μM/mM; completely tolerant: 3.83 ± 0.04; partially tolerant: 3.8 ± 0.06; reactive: 3.7 ± 0.04] (P = 0.008). The frequency of genetic polymorphisms of IDO did not reveal a significant association with Trp, Kyn, and Kyn/Trp in healthy and food-allergic cases. Culture of PBMC experiments yielded that IDO mRNA expression was not different between tolerant and reactive groups. IL-4 synthesis when stimulated with casein increased significantly in subjects who are reactive and tolerant to foods (P = 0.042, P = 0.006, respectively). Increase in IL-10 synthesis was observed only in children tolerant to milk, but not in reactive ones. IFN-γ synthesis, when stimulated with IL-2 and β-lactoglobulin in cell culture, was significantly higher in subjects tolerant to milk than in the reactive ones (P = 0.005 and P = 0.029, respectively). CONCLUSION Our results imply the probability of involvement of IDO in development of tolerance process, and we presume that high IDO activity is associated with nonresponsiveness to food allergens despite allergen sensitization.
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Affiliation(s)
- B. Buyuktiryaki
- Division of Pediatric Allergy; Hacettepe University School of Medicine; Ankara Turkey
| | - U. M. Sahiner
- Division of Pediatric Allergy; Hacettepe University School of Medicine; Ankara Turkey
| | - G. Girgin
- Division of Toxicology; Hacettepe University School of Pharmacy; Ankara Turkey
| | - E. Birben
- Division of Pediatric Allergy; Hacettepe University School of Medicine; Ankara Turkey
| | - O. U. Soyer
- Division of Pediatric Allergy; Hacettepe University School of Medicine; Ankara Turkey
| | - O. Cavkaytar
- Division of Pediatric Allergy; Hacettepe University School of Medicine; Ankara Turkey
| | - C. Cetin
- Department of Nutrition and Dietetics; Hacettepe University Faculty of Health Sciences; Ankara Turkey
| | - E. Arik Yilmaz
- Division of Pediatric Allergy; Hacettepe University School of Medicine; Ankara Turkey
| | - S. T. Yavuz
- Division of Pediatric Allergy; GATA Military School of Medicine; Ankara Turkey
| | - O. Kalayci
- Division of Pediatric Allergy; Hacettepe University School of Medicine; Ankara Turkey
| | - T. Baydar
- Division of Toxicology; Hacettepe University School of Pharmacy; Ankara Turkey
| | - C. Sackesen
- Division of Pediatric Allergy; Hacettepe University School of Medicine; Ankara Turkey
- Division of Pediatric Allergy; Koc University School of Medicine; Istanbul Turkey
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16
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Mole DJ, Webster SP, Uings I, Zheng X, Binnie M, Wilson K, Hutchinson JP, Mirguet O, Walker A, Beaufils B, Ancellin N, Trottet L, Bénéton V, Mowat CG, Wilkinson M, Rowland P, Haslam C, McBride A, Homer NZM, Baily JE, Sharp MGF, Garden OJ, Hughes J, Howie SEM, Holmes DS, Liddle J, Iredale JP. Kynurenine-3-monooxygenase inhibition prevents multiple organ failure in rodent models of acute pancreatitis. Nat Med 2016; 22:202-9. [PMID: 26752518 PMCID: PMC4871268 DOI: 10.1038/nm.4020] [Citation(s) in RCA: 105] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2015] [Accepted: 11/30/2015] [Indexed: 12/28/2022]
Abstract
Acute pancreatitis (AP) is a common and devastating inflammatory condition of the pancreas that is considered to be a paradigm of sterile inflammation leading to systemic multiple organ dysfunction syndrome (MODS) and death. Acute mortality from AP-MODS exceeds 20% (ref. 3), and the lifespans of those who survive the initial episode are typically shorter than those of the general population. There are no specific therapies available to protect individuals from AP-MODS. Here we show that kynurenine-3-monooxygenase (KMO), a key enzyme of tryptophan metabolism, is central to the pathogenesis of AP-MODS. We created a mouse strain that is deficient for Kmo (encoding KMO) and that has a robust biochemical phenotype that protects against extrapancreatic tissue injury to the lung, kidney and liver in experimental AP-MODS. A medicinal chemistry strategy based on modifications of the kynurenine substrate led to the discovery of the oxazolidinone GSK180 as a potent and specific inhibitor of KMO. The binding mode of the inhibitor in the active site was confirmed by X-ray co-crystallography at 3.2 Å resolution. Treatment with GSK180 resulted in rapid changes in the levels of kynurenine pathway metabolites in vivo, and it afforded therapeutic protection against MODS in a rat model of AP. Our findings establish KMO inhibition as a novel therapeutic strategy in the treatment of AP-MODS, and they open up a new area for drug discovery in critical illness.
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Affiliation(s)
- Damian J Mole
- Medical Research Council Centre for Inflammation Research, University of Edinburgh, Edinburgh, UK
- Clinical Surgery, University of Edinburgh, Edinburgh, UK
| | - Scott P Webster
- University/British Heart Foundation Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK
| | - Iain Uings
- Discovery Partnerships with Academia, GlaxoSmithKline, Stevenage, UK
| | - Xiaozhong Zheng
- Medical Research Council Centre for Inflammation Research, University of Edinburgh, Edinburgh, UK
| | - Margaret Binnie
- University/British Heart Foundation Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK
| | - Kris Wilson
- University/British Heart Foundation Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK
| | | | | | - Ann Walker
- Discovery Partnerships with Academia, GlaxoSmithKline, Stevenage, UK
| | | | | | | | | | | | - Martin Wilkinson
- EastChem School of Chemistry, University of Edinburgh, Edinburgh, UK
| | - Paul Rowland
- Molecular Discovery Research, GlaxoSmithKline, Stevenage, UK
| | - Carl Haslam
- Molecular Discovery Research, GlaxoSmithKline, Stevenage, UK
| | - Andrew McBride
- University/British Heart Foundation Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK
| | | | - James E Baily
- University/British Heart Foundation Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK
| | - Matthew G F Sharp
- Central Bioresearch Services, University of Edinburgh, Edinburgh, UK
| | - O James Garden
- Clinical Surgery, University of Edinburgh, Edinburgh, UK
| | - Jeremy Hughes
- Medical Research Council Centre for Inflammation Research, University of Edinburgh, Edinburgh, UK
| | - Sarah E M Howie
- Medical Research Council Centre for Inflammation Research, University of Edinburgh, Edinburgh, UK
| | - Duncan S Holmes
- Discovery Partnerships with Academia, GlaxoSmithKline, Stevenage, UK
| | - John Liddle
- Discovery Partnerships with Academia, GlaxoSmithKline, Stevenage, UK
| | - John P Iredale
- Medical Research Council Centre for Inflammation Research, University of Edinburgh, Edinburgh, UK
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17
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Badawy AAB. Tryptophan metabolism, disposition and utilization in pregnancy. Biosci Rep 2015; 35:e00261. [PMID: 26381576 PMCID: PMC4626867 DOI: 10.1042/bsr20150197] [Citation(s) in RCA: 112] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Revised: 08/27/2015] [Accepted: 09/16/2015] [Indexed: 12/26/2022] Open
Abstract
Tryptophan (Trp) requirements in pregnancy are several-fold: (1) the need for increased protein synthesis by mother and for fetal growth and development; (2) serotonin (5-HT) for signalling pathways; (3) kynurenic acid (KA) for neuronal protection; (4) quinolinic acid (QA) for NAD(+) synthesis (5) other kynurenines (Ks) for suppressing fetal rejection. These goals could not be achieved if maternal plasma [Trp] is depleted. Although plasma total (free + albumin-bound) Trp is decreased in pregnancy, free Trp is elevated. The above requirements are best expressed in terms of a Trp utilization concept. Briefly, Trp is utilized as follows: (1) In early and mid-pregnancy, emphasis is on increased maternal Trp availability to meet the demand for protein synthesis and fetal development, most probably mediated by maternal liver Trp 2,3-dioxygenase (TDO) inhibition by progesterone and oestrogens. (2) In mid- and late pregnancy, Trp availability is maintained and enhanced by the release of albumin-bound Trp by albumin depletion and non-esterified fatty acid (NEFA) elevation, leading to increased flux of Trp down the K pathway to elevate immunosuppressive Ks. An excessive release of free Trp could undermine pregnancy by abolishing T-cell suppression by Ks. Detailed assessment of parameters of Trp metabolism and disposition and related measures (free and total Trp, albumin, NEFA, K and its metabolites and pro- and anti-inflammatory cytokines in maternal blood and, where appropriate, placental and fetal material) in normal and abnormal pregnancies may establish missing gaps in our knowledge of the Trp status in pregnancy and help identify appropriate intervention strategies.
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Affiliation(s)
- Abdulla A-B Badawy
- School of Health Sciences, Cardiff Metropolitan University, Western Avenue, Cardiff CF5 2YB, Wales, U.K.
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18
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The role of FcεRI expressed in dendritic cells and monocytes. Cell Mol Life Sci 2015; 72:2349-60. [PMID: 25715742 DOI: 10.1007/s00018-015-1870-x] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Revised: 02/17/2015] [Accepted: 02/20/2015] [Indexed: 01/23/2023]
Abstract
Early studies regarding the function of FcεRI in dendritic cells (DCs) and monocytes have focused on its role in mediating inflammatory signaling and enhancing T cell immunity. It has been the case in part because FcεRI is the major receptor that mediates allergic inflammatory signaling in mast cells and basophils and because DCs and monocytes are antigen presenting cells capable of activating naïve and/or effector T cells. These studies have led to the general belief that FcεRI-mediated DC signaling and antigen presentation promote development and activation of Th2 cells and contribute to allergic inflammatory diseases. However, this belief has long suffered from a lack of evidence. Recently, studies have emerged that provide evidence supporting an opposing role: that FcεRI on DCs instead promotes immune homeostasis and regulation. In this review, we will update the current status of our understanding of FcεRI biology and function, with a specific focus on DCs and monocytes.
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Loubaki L, Chabot D, Bazin R. Involvement of the TNF-α/TGF-β/IDO axis in IVIg-induced immune tolerance. Cytokine 2014; 71:181-7. [PMID: 25461397 DOI: 10.1016/j.cyto.2014.10.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2014] [Revised: 10/17/2014] [Accepted: 10/28/2014] [Indexed: 01/20/2023]
Abstract
The immune tolerance induced by IVIg treatment is generally attributed to its capacity to modulate the functions of antigen presenting cells and to induce the expansion of regulatory T cells by mechanisms that are not well-defined. Herein, we investigated the contribution of the TNF-α/TGF-β/IDO axis to IVIg-induced immune tolerance. We show that high dose IVIg is able to markedly increase the expression (>3 fold) of the well-known tolerogenic cytokine TGF-β in monocytes. In addition, the expression of TNF-α, a pleiotropic cytokine that controls TGF-β-induced tolerogenic effects, as well as of its cognate receptors (TNF-R1 and TNF-R2) is also significantly increased following IVIg treatment. Along with TNF-α, the expression of the enzyme and signaling protein IDO, known to mediate TGF-β dependant tolerogenic effect, is similarly increased following IVIg treatment. We thus propose that the complex interplay between plasticity of immune cells and environmental modifications in which the TNF-α/TGF-β/IDO axis may represent a new mechanism contributing to the development of tolerance in IVIg-treated patients.
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MESH Headings
- Cells, Cultured
- Flow Cytometry
- Gene Expression/drug effects
- Gene Expression/immunology
- Humans
- Immunoglobulins, Intravenous/immunology
- Immunoglobulins, Intravenous/pharmacology
- Indoleamine-Pyrrole 2,3,-Dioxygenase/immunology
- Indoleamine-Pyrrole 2,3,-Dioxygenase/metabolism
- Monocytes/drug effects
- Monocytes/immunology
- Monocytes/metabolism
- Receptors, Tumor Necrosis Factor, Type I/immunology
- Receptors, Tumor Necrosis Factor, Type I/metabolism
- Receptors, Tumor Necrosis Factor, Type II/immunology
- Receptors, Tumor Necrosis Factor, Type II/metabolism
- Reverse Transcriptase Polymerase Chain Reaction
- Signal Transduction/drug effects
- Signal Transduction/immunology
- Transforming Growth Factor beta/genetics
- Transforming Growth Factor beta/immunology
- Transforming Growth Factor beta/metabolism
- Tumor Necrosis Factor-alpha/genetics
- Tumor Necrosis Factor-alpha/immunology
- Tumor Necrosis Factor-alpha/metabolism
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Affiliation(s)
- Lionel Loubaki
- Department of Research and Development, Héma-Québec, Québec (Qc), Canada
| | - Dominique Chabot
- Department of Research and Development, Héma-Québec, Québec (Qc), Canada; Department of Biochemistry, Microbiology and Bioinformatics, Laval University, Québec (Qc), Canada
| | - Renée Bazin
- Department of Research and Development, Héma-Québec, Québec (Qc), Canada; Department of Biochemistry, Microbiology and Bioinformatics, Laval University, Québec (Qc), Canada.
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The tryptophan utilization concept in pregnancy. Obstet Gynecol Sci 2014; 57:249-59. [PMID: 25105097 PMCID: PMC4124085 DOI: 10.5468/ogs.2014.57.4.249] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Revised: 05/14/2014] [Accepted: 05/14/2014] [Indexed: 11/26/2022] Open
Abstract
The decrease in maternal plasma total (free + albumin-bound) tryptophan (Trp) during the third pregnancy trimester is attributed to induction of indoleamine 2,3-dioxygenase (IDO). When measured, free [Trp] is increased because of albumin depletion and non-esterified fatty acid elevation. The Trp depletion concept in pregnancy is therefore not supported because of incorrect interpretation of changes in Trp disposition and also for not addressing mouse strain differences in Trp-related responses and potential inhibition of Trp transport by the IDO inhibitor 1-methyl tryptophan. Application of the Trp utilization concept in pregnancy offers several physiological advantages favoring fetal development and successful outcome, namely provision of Trp for fetal protein synthesis and growth, serotonin for signaling pathways, kynurenic acid for neuroprotection, quinolinic acid for NAD+ synthesis, and other kynurenines for suppression of T cell responses. An excessive increase in Trp availability could compromise pregnancy by undermining T cell suppression, e.g., in pre-eclampsia.
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Shamji MH. Mechanisms of Allergen-Specific Sublingual Immunotherapy and the Use of Biological Markers in Allergic Rhinitis. CURRENT TREATMENT OPTIONS IN ALLERGY 2014. [DOI: 10.1007/s40521-013-0009-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Cappella A, Durham SR. Allergen immunotherapy for allergic respiratory diseases. Hum Vaccin Immunother 2012; 8:1499-512. [PMID: 23095870 PMCID: PMC3660772 DOI: 10.4161/hv.21629] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2012] [Revised: 07/18/2012] [Accepted: 07/26/2012] [Indexed: 01/27/2023] Open
Abstract
Allergen specific immunotherapy involves the repeated administration of allergen products in order to induce clinical and immunologic tolerance to the offending allergen. Immunotherapy is the only etiology-based treatment that has the potential for disease modification, as reflected by longterm remission following its discontinuation and possibly prevention of disease progression and onset of new allergic sensitizations. Whereas subcutaneous immunotherapy is of proven value in allergic rhinitis and asthma there is a risk of untoward side effects including rarely anaphylaxis. Recently the sublingual route has emerged as an effective and safer alternative. Whereas the efficacy of SLIT in seasonal allergy is now well-documented in adults and children, the available data for perennial allergies and asthma is less reliable and particularly lacking in children. This review evaluates the efficacy, safety and longterm benefits of SCIT and SLIT and highlights new findings regarding mechanisms, potential biomarkers and recent novel approaches for allergen immunotherapy.
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Affiliation(s)
- Antonio Cappella
- Section Allergy and Clinical Immunology, National Heart and Lung Institute; Imperial College; London UK
| | - Stephen R. Durham
- Section Allergy and Clinical Immunology, National Heart and Lung Institute; Imperial College; London UK
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Chen KW, Blatt K, Thomas WR, Swoboda I, Valent P, Valenta R, Vrtala S. Hypoallergenic Der p 1/Der p 2 combination vaccines for immunotherapy of house dust mite allergy. J Allergy Clin Immunol 2012; 130:435-43.e4. [PMID: 22789398 DOI: 10.1016/j.jaci.2012.05.035] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2011] [Revised: 05/16/2012] [Accepted: 05/23/2012] [Indexed: 11/16/2022]
Abstract
BACKGROUND More than 50% of allergic patients have house dust mite (HDM) allergy. Group 1 and 2 allergens are the major HDM allergens. OBJECTIVE We sought to produce and perform preclinical characterization of a recombinant hypoallergenic combination vaccine for specific immunotherapy of HDM allergy. METHODS Synthetic genes coding for 2 hybrid proteins consisting of reassembled Der p 1 and Der p 2 fragments with (recombinant Der p 2 [rDer p 2]/1C) and without (rDer p 2/1S) cysteines were expressed in Escherichia coli and purified to homogeneity by means of affinity chromatography. Protein fold was determined by using circular dichroism analysis, allergenic activity was determined by testing IgE reactivity and using basophil activation assays, and the presence of T-cell epitopes was determined based on lymphoproliferation in allergic patients. Mice and rabbits were immunized to study the molecules' ability to induce an allergic response and whether they induce allergen-specific IgG capable of inhibiting allergic patients' IgE binding to the allergens, respectively. RESULTS rDer p 2/1C and rDer p 2/1S were expressed in large amounts in E coli as soluble and folded proteins. Because of the lack of disulfide bonds, rDer p 2/1S did not form aggregates and was obtained as a monomeric protein, whereas rDer p 2/1C did form aggregates. Both hypoallergens lacked relevant IgE reactivity and had reduced ability to induce allergic inflammation and allergic responses but induced similar T-cell proliferation as the wild-type allergens. Immunization with the hypoallergens (rDer p 2/1S > rDer p 2/1C) induced IgG antibodies in rabbits that inhibited the IgE reactivity of patients with HDM allergy to Der p 1 and Der p 2. CONCLUSION The preclinical characterization indicates that particularly rDer p 2/1S can be used as a safe hypoallergenic molecule for both tolerance and vaccination approaches to treat HDM allergy.
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Affiliation(s)
- Kuan-Wei Chen
- Division of Immunopathology, Department of Pathophysiology and Allergy Research, Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
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Bubnoff D, Bieber T. The indoleamine 2,3-dioxygenase (IDO) pathway controls allergy. Allergy 2012; 67:718-25. [PMID: 22519427 DOI: 10.1111/j.1398-9995.2012.02830.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/19/2012] [Indexed: 11/30/2022]
Abstract
A series of recent studies have demonstrated that the immunoregulatory pathway of tryptophan catabolism, initiated by the enzyme indoleamine 2,3-dioxygenase (IDO), is a critical participant in allergic inflammation. Originally known for its regulatory function during pregnancy and during chronic inflammation in tumorigenesis and infection, the activity of IDO seems to positively modify the inflammatory state of atopy or allergy. The tryptophan degradation pathway is important for tolerance induction during systemic allergen immunotherapy. Here, we focus on recent findings that establish the IDO pathway as central to allergic inflammation.
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Affiliation(s)
- D. Bubnoff
- Department of Dermatology and Allergy; Friedrich-Wilhelms-University; Bonn; Germany
| | - T. Bieber
- Department of Dermatology and Allergy; Friedrich-Wilhelms-University; Bonn; Germany
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Li L, Huang L, Lemos HP, Mautino M, Mellor AL. Altered tryptophan metabolism as a paradigm for good and bad aspects of immune privilege in chronic inflammatory diseases. Front Immunol 2012; 3:109. [PMID: 22593757 PMCID: PMC3350084 DOI: 10.3389/fimmu.2012.00109] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2012] [Accepted: 04/17/2012] [Indexed: 01/01/2023] Open
Abstract
The term "immune privilege" was coined to describe weak immunogenicity (hypo-immunity) that manifests in some transplant settings. We extended this concept to encompass hypo-immunity that manifests at local sites of inflammation relevant to clinical diseases. Here, we focus on emerging evidence that enhanced tryptophan catabolism is a key metabolic process that promotes and sustains induced immune privilege, and discuss the implications for exploiting this knowledge to improve treatments for hypo-immune and hyper-immune syndromes using strategies to manipulate tryptophan metabolism.
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Affiliation(s)
- Lingqian Li
- Immunotherapy Center, Georgia Health Sciences University Augusta, GA, USA
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Gros E, Petzold S, Maintz L, Bieber T, Novak N. Reduced IFN-γ receptor expression and attenuated IFN-γ response by dendritic cells in patients with atopic dermatitis. J Allergy Clin Immunol 2011; 128:1015-21. [PMID: 21774972 DOI: 10.1016/j.jaci.2011.05.043] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2010] [Revised: 05/25/2011] [Accepted: 05/25/2011] [Indexed: 12/21/2022]
Abstract
BACKGROUND Atopic dermatitis (AD) is characterized by a predominance of T(H)2 immune reactions but weaker T(H)1 immune responses in acute skin lesions. OBJECTIVES To evaluate whether enhanced T(H)2 immunity in patients with AD might impair T(H)1 immune responses by affecting the IFN-γ responsiveness of antigen-presenting cells, we investigated IFN-γ receptor and IL-4 receptor α chain expression, IFN-γ signaling, and the expression of IFN-γ-responsive mediators in dendritic cells (DCs) and their precursors from patients with AD compared with those from healthy subjects. METHODS Skin biopsy specimens were obtained and both monocytes and monocyte-derived dendritic cells (MoDCs) from patients with AD (n = 86) and control subjects (n = 84) were analyzed by means of flow cytometry, real-time PCR, ELISA, and HPLC. RESULTS We observed lower IFN-γ receptor II expression combined with higher IL-4 receptor α chain expression on epidermal DCs, monocytes, and MoDCs from patients with AD. Induction of IFN-γ-inducible factors, such as interferon regulatory factor 1, interferon-inducible protein 10, and indoleamine 2,3-dioxygenase, was attenuated in IFN-γ-pulsed MoDCs from patients with AD. Weaker signal transducer and activator of transcription 1 activation mirrored by lower phosphorylated signal transducer and activator of transcription 1 levels in response to IFN-γ stimulation could be observed in epidermal DCs, monocytes, and MoDCs from patients with AD. CONCLUSION Impaired IFN-γ signaling together with attenuated IFN-γ responses in DCs and their precursor cells might contribute to the T(H)2 bias in patients with AD.
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Affiliation(s)
- Eva Gros
- Department of Dermatology and Allergy, University of Bonn Medical Center, Bonn, Germany
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Development of mucosal immunity in children: a rationale for sublingual immunotherapy? J Allergy (Cairo) 2011; 2012:492761. [PMID: 22121386 PMCID: PMC3205711 DOI: 10.1155/2012/492761] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2011] [Accepted: 08/22/2011] [Indexed: 01/14/2023] Open
Abstract
The mucosal immune system has bidirectional tasks to mount an effective defense against invading harmful pathogens and to suppress the immune response to alimentary antigens and commensal bacterial flora. Oral tolerance is a suppression of the mucosal immune pathway related to a specific immunophenotype of the dendritic cells and an induction of the regulatory T cells as well as with the silencing of the effector T cell response by anergy and deletion. The physiological dynamic process of the anatomical and functional maturation of the immune system occurring in children during pre- and postnatal periods is a significant factor, having an impact on the fine balance between the activation and the suppression of the immune response. In this paper, mechanisms of mucosal immunity and tolerance induction in terms of maturational issues are discussed with a special emphasis on the implications for a novel therapeutic intervention in allergic diseases via the sublingual route.
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von Bubnoff D, Wilms H, Scheler M, Brenk M, Koch S, Bieber T. Human myeloid dendritic cells are refractory to tryptophan metabolites. Hum Immunol 2011; 72:791-7. [DOI: 10.1016/j.humimm.2011.05.026] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2011] [Revised: 05/24/2011] [Accepted: 05/25/2011] [Indexed: 12/18/2022]
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Abstract
Allergen immunotherapy is allergen-specific, allergen dose- and time-dependent and is associated with long-term clinical and immunological tolerance that persists for years after discontinuation. Successful immunotherapy is accompanied by the suppression of numbers of T-helper 2 (Th2) effector cells, eosinophils, basophils, c-kit+mast cells and neutrophils infiltration in target organs, induction of IL-10 and/or TGF-β+Treg cells and increases in 'protective' non-inflammatory blocking antibodies, particularly IgG4 and IgA2 subclasses with inhibitory activity. These events are accompanied by a reduction and/or a redirection of underlying antigen-specific Th2-type T cell-driven hypersensitivity to the allergen(s) used for therapy. This suppression occurs within weeks or months as a consequence of the appearance of a population of regulatory T cells that exert their effects by mechanisms involving cell-cell contact, but also by the release of cytokines such as IL-10 (increases IgG4) and TGF-β (increases specific IgA). The more delayed-in-time appearance of antigen-specific T-helper 1 responses and alternative mechanisms such as Th2 cell anergy and/or apoptosis may also be involved. The mechanisms of sublingual immunotherapy are similar to those following a subcutaneous administration of allergen, whereas it is likely that additional events following antigen presentation in the sublingual mucosa and regional lymph nodes are involved. These insights have resulted in novel approaches and portend future biomarkers that may be surrogate or predictive of the clinical response to treatment.
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Affiliation(s)
- M H Shamji
- Allergy and Clinical Immunology Section, Medical Research Council and Asthma UK Centre for Allergic Mechanisms of Asthma, Faculty of Medicine, National Heart and Lung Institute, Imperial College London, London, UK.
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Von Bubnoff D, Scheler M, Wilms H, Fimmers R, Bieber T. Identification of IDO-positive and IDO-negative human dendritic cells after activation by various proinflammatory stimuli. THE JOURNAL OF IMMUNOLOGY 2011; 186:6701-9. [PMID: 21543643 DOI: 10.4049/jimmunol.1003151] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Dendritic cells (DCs) can induce tolerance or immunity. We identified and characterized an IDO-expressing and an IDO-negative human DC population after stimulation by various proinflammatory stimuli. IDO expression was strongly dependent on the maturation status of the cells (CD83-positive cells only). The two DC subpopulations remained IDO positive and IDO negative, respectively, over a time period of at least 48 h. IDO enzyme activity of human DCs was highest during stimulation by strongly maturation-inducing TLR ligands such as highly purified LPS (TLR4 ligand) or polyriboinosinic-polyribocytidilic acid (TLR3 ligand); factors of the adaptive immune system such as IFN-γ, a mixture of cytokines, and IFN-α had lesser stimulatory capacity for IDO induction and activity. After stimulation with CD40L, IDO-positive DCs expressed significantly increased levels of B7 family molecules such as CD40, CD80, CD86, ICOS ligand, as well as PD-L1 (B7-H1) and PD-L2 (B7-DC) compared with the IDO-negative DC subset. At the same time, the inhibitory receptors Ig-like transcripts 3 and 4 were significantly downregulated on IDO-positive cells. Functionally, IDO-positive DCs produced significantly more IL-1β and IL-15 and less IL-10 and IL-6 than the IDO-negative subset after CD40L stimulation. These results show that IDO expression is associated with a distinctive phenotype and functional capacity in mature DCs. It seems likely that the IDO-positive DC subset possesses a regulatory function and might skew a T cell response toward tolerance.
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Affiliation(s)
- Dagmar Von Bubnoff
- Department of Dermatology and Allergy, Friedrich-Wilhelms-University of Bonn, 53105 Bonn, Germany.
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Scadding G, Durham SR. Mechanisms of Sublingual Immunotherapy. Immunol Allergy Clin North Am 2011; 31:191-209, viii. [DOI: 10.1016/j.iac.2011.02.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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Peng WM, Yu CF, Kolanus W, Mazzocca A, Bieber T, Kraft S, Novak N. Tetraspanins CD9 and CD81 are molecular partners of trimeric FcɛRI on human antigen-presenting cells. Allergy 2011; 66:605-11. [PMID: 21241315 DOI: 10.1111/j.1398-9995.2010.02524.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
BACKGROUND Most functions of tetraspanins are not related to cell-surface receptor ligand binding, but are mediated by direct interactions with their partner proteins. Functions of trimeric FcɛRI, expressed by antigen-presenting cells (APCs), range from amplification of allergic inflammatory reactions to their active suppression. Cell-type-specific protein-protein interactions might play a role in the regulation of these bidirectional tasks. Therefore, we intended to study the interactions of trimeric FcɛRI with tetraspanins. METHODS The expression levels of tetraspanins CD9, CD37, CD53, CD63, CD81, CD82, and CD151 on skin dendritic cells of atopic dermatitis (AD) patients or healthy individuals were detected by flow cytometry. Tetraspanin expression on FcɛRI(pos) and FcɛRI(neg) monocyte subpopulations was evaluated. Flow cytometry, confocal microscopy, immunoprecipitation, and immunoblotting experiments were performed to observe the relationship between tetraspanins CD9 and CD81 and FcɛRI. Furthermore, plate stimulation experiments were performed, and cytokines in the supernatants were detected. RESULTS We found that human FcɛRI(pos) APCs expressed high amounts of tetraspanins and that the tetraspanins CD9 and CD81 were associated with FcɛRI. Concomitant activation of FcɛRI and CD9 on human monocytes increased FcɛRI-mediated cytokine release. CONCLUSION Taken together, we show for the first time that CD9 and CD81 act as molecular partners of trimeric FcɛRI on human APC, which might be of importance in allergic diseases such as AD.
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Affiliation(s)
- W M Peng
- Department of Dermatology and Allergy, University of Bonn Medical, Bonn, Germany
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Indoleamine 2,3-dioxygenase-expressing myeloid dendritic cells and macrophages in infectious and noninfectious cutaneous granulomas. J Am Acad Dermatol 2011; 65:819-832. [PMID: 21501890 DOI: 10.1016/j.jaad.2010.07.050] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2010] [Revised: 07/06/2010] [Accepted: 07/20/2010] [Indexed: 01/06/2023]
Abstract
BACKGROUND The enzyme indoleamine 2,3-dioxygenase (IDO) degrades the essential amino acid tryptophan, and this degradation is an immunosuppressive mechanism that is mainly used by antigen-presenting cells. IDO-expressing dendritic cells and macrophages have previously been identified as components of lymph node granulomas after Listeria monocytogenes infection. In this study we undertook an analysis of IDO expression in granulomas of infectious and noninfectious origin in the human skin. METHODS Lesional skin biopsy specimens (n = 22) from different granulomatous skin disorders (lupus vulgaris, sarcoidosis, granuloma annulare, leprosy) were analyzed. Immunohistochemistry was performed to identify and locate the enzyme IDO within the inflammatory granulomatous infiltrate (IDO, CD11c, CD68, S100, CD3, Foxp3). Two-color immunofluorescence of IDO in combination with multiple markers was applied to characterize the IDO-expressing cells. RESULTS Cutaneous granulomas of different origin strongly express IDO, mainly in the center and in the ring wall of the granulomas. We demonstrate that in infectious, but also in noninfectious human cutaneous granulomas the large myeloid CD11c(+)S100(+)CD68(-) dendritic cells and the CD68(+) macrophages express IDO. LIMITATIONS This study was limited by the lack of details about the exact stage or maturity of granuloma formation in the specimens investigated. CONCLUSION These findings reveal that IDO expression in myeloid dendritic cells and macrophages is part of an integrated response of granuloma formation, which may be a unifying feature of granulomatous reactions in the skin.
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Johnson BA, Baban B, Mellor AL. Targeting the immunoregulatory indoleamine 2,3 dioxygenase pathway in immunotherapy. Immunotherapy 2011; 1:645-61. [PMID: 20161103 DOI: 10.2217/imt.09.21] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Natural immune tolerance is a formidable barrier to successful immunotherapy to treat established cancers and chronic infections. Conversely, creating robust immune tolerance via immunotherapy is the major goal in treating autoimmune and allergic diseases, and enhancing survival of transplanted organs and tissues. In this review, we focus on a natural mechanism that creates local T-cell tolerance in many clinically relevant settings of chronic inflammation involving expression of the cytosolic enzyme indoleamine 2,3-dioxygenase (IDO) by specialized subsets of dendritic cells. IDO-expressing dendritic cells suppress antigen-specific T-cell responses directly, and induce bystander suppression by activating regulatory T cells. Thus, manipulating IDO is a promising strategy to treat a range of chronic inflammatory diseases.
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Affiliation(s)
- Burles A Johnson
- Immunotherapy Center & Department of Medicine, Medical College of Georgia, Augusta, GA 30912, USA.
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Bussmann C, Xia J, Allam JP, Maintz L, Bieber T, Novak N. Early markers for protective mechanisms during rush venom immunotherapy. Allergy 2010; 65:1558-65. [PMID: 20584008 DOI: 10.1111/j.1398-9995.2010.02430.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
BACKGROUND Allergen-specific venom immunotherapy (VIT) represents the only rational-based option to treat allergic sensitizations against bee and wasp venom. So far, there is not much knowledge about early induction of protective and tolerogenic pathways during VIT. OBJECTIVES To identify the earliest markers for protective mechanisms against allergic reactions in the peripheral blood during the build-up phase of VIT. METHODS PBMC and monocytes were isolated, and serum samples were taken before and during a five day build-up phase from 65 hymenoptera venom allergic patients. Expression level of tolerogenic markers was analyzed on mRNA and protein level. Serum levels of different soluble tolerogenic factors were measured. RESULTS We observed significantly enhanced tryptophan degradation, elevated ILT4 expression of monocytes as well as IL-10 production of CD3(+) T cells only a few hours after the first injection on day 1, followed by increased IL-10 serum levels, monocyte apoptosis and elevated intracellular cAMP levels of monocytes on day 3 combined with a higher ILT3 protein expression and IL-10 secretion of monocytes on day 5. CONCLUSION From these data, we conclude that tryptophan depletion, ILT3/4-mediated inhibition, higher IL-10 production as well as intracellular cAMP might contribute to early induction of protective mechanisms against allergic reactions during the build-up phase of VIT.
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MESH Headings
- Adolescent
- Adult
- Aged
- Animals
- Bee Venoms/immunology
- Bee Venoms/therapeutic use
- Cell Separation
- Desensitization, Immunologic
- Fas Ligand Protein/blood
- Fas Ligand Protein/immunology
- Fas Ligand Protein/metabolism
- Female
- Flow Cytometry
- Gene Expression
- Humans
- Hypersensitivity/immunology
- Hypersensitivity/prevention & control
- Indoleamine-Pyrrole 2,3,-Dioxygenase/blood
- Indoleamine-Pyrrole 2,3,-Dioxygenase/immunology
- Indoleamine-Pyrrole 2,3,-Dioxygenase/metabolism
- Interleukin-10/biosynthesis
- Interleukin-10/immunology
- Male
- Membrane Glycoproteins
- Middle Aged
- Monocytes/immunology
- Monocytes/metabolism
- RNA, Messenger/analysis
- Receptors, Cell Surface/blood
- Receptors, Cell Surface/immunology
- Receptors, Cell Surface/metabolism
- Receptors, Immunologic
- Reverse Transcriptase Polymerase Chain Reaction
- Toll-Like Receptor 4/blood
- Toll-Like Receptor 4/immunology
- Toll-Like Receptor 4/metabolism
- Up-Regulation
- Wasp Venoms/immunology
- Wasp Venoms/therapeutic use
- Young Adult
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Affiliation(s)
- C Bussmann
- Department of Dermatology and Allergy, University of Bonn, Bonn, Germany
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Kynurenine metabolism in health and disease. Amino Acids 2010; 41:1173-83. [PMID: 20972599 DOI: 10.1007/s00726-010-0787-9] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2010] [Accepted: 10/08/2010] [Indexed: 12/15/2022]
Abstract
Kynurenine is a small molecule derived from tryptophan when this amino acid is metabolised via the kynurenine pathway. The biological activity of kynurenine and its metabolites (kynurenines) is well recognised. Therefore, understanding the regulation of the subsequent biochemical reactions is essential for the design of therapeutic strategies which aim to interfere with the kynurenine pathway. However, kynurenine concentration in the body may not only be determined by the efficiency of kynurenine synthesis but also by the rate of kynurenine clearance. In this review, current knowledge about the mechanisms of kynurenine production and routes of its clearance is presented. In addition, the involvement of kynurenine and its metabolites in the biology of different T cell subsets (including Th17 cells and regulatory T cells) and neuronal cells is discussed.
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CHAPTER 3: MECHANISMS OF SUBLINGUAL IMMUNOTHERAPY. World Allergy Organ J 2009. [DOI: 10.1097/01.wox.0000365043.86788.1a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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Canonica GW, Bousquet J, Casale T, Lockey RF, Baena-Cagnani CE, Pawankar R, Potter PC, Bousquet PJ, Cox LS, Durham SR, Nelson HS, Passalacqua G, Ryan DP, Brozek JL, Compalati E, Dahl R, Delgado L, van Wijk RG, Gower RG, Ledford DK, Filho NR, Valovirta EJ, Yusuf OM, Zuberbier T. Sub-lingual immunotherapy: world allergy organization position paper 2009. World Allergy Organ J 2009; 2:233-81. [PMID: 23268425 PMCID: PMC3488881 DOI: 10.1097/wox.0b013e3181c6c379] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
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Abstract
Allergen-specific sublingual immunotherapy is now recognized to be an efficacious and well-tolerated treatment for allergic rhinitis. Emerging treatment strategies are also aimed at the primary treatment of allergic asthma, particularly allergy to house dust mites. Knowledge of the exact mechanisms of action of sublingual immunotherapy is at a basic level, although there appear to be similarities to the immunological changes seen in subcutaneous immunotherapy. An improved understanding should allow the development of more effective treatment programs and widen the potential use of this form of immunotherapy. This review discusses the possible mechanism of action of sublingual immunotherapy, including data from animal and clinical studies, while comparing this with the current understanding of subcutaneous immunotherapy.
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Affiliation(s)
- Guy Scadding
- Allergy and Clinical Immunology, Imperial College, London, UK
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Brenk M, Scheler M, Koch S, Neumann J, Takikawa O, Häcker G, Bieber T, von Bubnoff D. Tryptophan deprivation induces inhibitory receptors ILT3 and ILT4 on dendritic cells favoring the induction of human CD4+CD25+ Foxp3+ T regulatory cells. THE JOURNAL OF IMMUNOLOGY 2009; 183:145-54. [PMID: 19535644 DOI: 10.4049/jimmunol.0803277] [Citation(s) in RCA: 121] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Tryptophan catabolism through IDO activity can cause nonresponsiveness and tolerance acting on T cells. Given the crucial importance of dendritic cells (DCs) in the initiation of a T cell response, surprisingly little is known about the impact of IDO activity and tryptophan deprivation on DCs themselves. In the present study, we show that human DCs differentiated under low-tryptophan conditions acquire strong tolerogenic capacity. This effect is associated with a markedly decreased Ag uptake as well as the down-regulation of costimulatory molecules (CD40, CD80). In contrast, the inhibitory receptors ILT3 and ILT4 are significantly increased. Functionally, tryptophan-deprived DCs show a reduced capacity to stimulate T cells, which can be restored by blockade of ILT3. Moreover, ILT3(high)ILT4(high) DCs lead to the induction of CD4(+)CD25(+) Foxp3(+) T regulatory cells with suppressive activity from CD4(+)CD25(-) T cells. The generation of ILT3(high)ILT4(high) DCs with tolerogenic properties by tryptophan deprivation is linked to a stress response pathway mediated by the GCN2 kinase. These results demonstrate that tryptophan degradation establishes a regulatory microenvironment for DCs, enabling these cells to induce T regulatory cells. The impact of IDO thus extends beyond local immune suppression to a systemic control of the immune response.
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Affiliation(s)
- Manuela Brenk
- Department of Dermatology and Allergy, Friedrich-Wilhelms-University of Bonn, Germany
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Mahanonda R, Jitprasertwong P, Sa-Ard-Iam N, Rerkyen P, Charatkulangkun O, Jansisyanont P, Nisapakultorn K, Yongvanichit K, Pichyangkul S. Effects of IL-17 on human gingival fibroblasts. J Dent Res 2008; 87:267-72. [PMID: 18296612 DOI: 10.1177/154405910808700314] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Interleukin (IL)-17 is present in inflammatory periodontal lesions, thus suggesting a role in mediating inflammation. We tested the hypothesis that IL-17, especially when combined with interferon (IFN)-gamma, may modulate the responses of human gingival fibroblasts (HGFs). IL-17 induced IL-8 and minimal intercellular adhesion molecule (ICAM)-1 expression. It had no effect on expression of HLA-DR, CD40, or the immune-suppressive enzyme indoleamine 2,3-dioxygenase (IDO). The effects of IL-17 on HGFs were compared with those of IFN-gamma. Unlike IL-17, IFN-gamma augmented the expression of HLA-DR, ICAM-1, and IDO, but not IL-8. Thus, IL-17 and IFN-gamma induce different HGF responses when administered separately. Interestingly, when IL-17 and IFN-gamma were combined, marked enhancement of ICAM-1, IL-8, and IDO expression by HGFs was observed. These findings suggest that IL-17, especially when combined with IFN-gamma, could play an important role in immune modulation through stimulation of HGFs in periodontal disease.
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Affiliation(s)
- R Mahanonda
- Department of Periodontology, Faculty of Dentistry, University, Henri Dunant Rd., Bangkok 10330, Thailand.
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Novak N, Haberstok J, Bieber T, Allam JP. The immune privilege of the oral mucosa. Trends Mol Med 2008; 14:191-8. [PMID: 18396104 DOI: 10.1016/j.molmed.2008.03.001] [Citation(s) in RCA: 161] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2008] [Revised: 02/25/2008] [Accepted: 03/04/2008] [Indexed: 01/22/2023]
Abstract
Despite high bacterial colonization and frequent allergen contact, acute inflammatory and allergic reactions are rarely seen in the oral mucosa. Therefore we assert that immune tolerance predominates at this site and antigen presenting cells, such as dendritic cells and different T cell subtypes, serve as key players in oral mucosal tolerance induction. In this article we describe the mechanisms that lead to tolerance induced in the oral mucosa and how they differ from tolerance induced in the lower gastrointestinal tract. Furthermore we discuss ways in which novel nonparenteral approaches for immune intervention, such as allergen-specific immunotherapy applied by way of the sublingual route, might be improved to target the tolerogenic properties of the sophisticated oral mucosal immune network.
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Affiliation(s)
- Natalija Novak
- Department of Dermatology and Allergy, University of Bonn, Sigmund-Freud-Str 25, 53105 Bonn, Germany.
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MULLEY WILLIAMR, NIKOLIC-PATERSON DAVIDJ. Indoleamine 2,3-dioxygenase in transplantation (Review Article). Nephrology (Carlton) 2008; 13:204-11. [DOI: 10.1111/j.1440-1797.2007.00921.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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Park YD, Park D, Bhak J, Yang JM. Proteomic approaches to the analysis of atopic dermatitis and new insights from interactomics. Proteomics Clin Appl 2008; 2:290-300. [DOI: 10.1002/prca.200780063] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Hasannejad H, Takahashi R, Kimishima M, Hayakawa K, Shiohara T. Selective impairment of Toll-like receptor 2–mediated proinflammatory cytokine production by monocytes from patients with atopic dermatitis. J Allergy Clin Immunol 2007; 120:69-75. [PMID: 17531301 DOI: 10.1016/j.jaci.2007.04.010] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2006] [Revised: 04/04/2007] [Accepted: 04/05/2007] [Indexed: 10/23/2022]
Abstract
BACKGROUND The skin of patients with atopic dermatitis (AD) exhibits a striking susceptibility to infection with gram-positive bacteria and herpes simplex virus (HSV), which are known to stimulate Toll-like receptor (TLR) 2. OBJECTIVE We investigated whether TLR2-mediated proinflammatory cytokine production by monocytes is selectively impaired in patients with AD and, if so, whether high FcvarepsilonRI levels on the monocytes could be related to the impairment. METHODS The 2 subpopulations of monocytes, CD14(dim) proinflammatory and CD14(bright) classical monocytes, from patients with AD and healthy control subjects were stimulated to produce IL-1beta and TNF-alpha with phorbol 12-myristate 13-acetate/ionomycin, LPS (TLR4 ligand), or Pam3Cys (TLR2 ligand) for 4 hours, and simultaneous flow cytometric assessment of surface phenotype and intracellular cytokine synthesis was performed. Surface expression of TLR2, TLR4, and FcvarepsilonRI on the monocyte subpopulations was also assessed by means of flow cytometry. RESULTS TLR2-mediated IL-1beta and TNF-alpha production by either the CD14(dim) or CD14(bright) monocytes was found to be selectively impaired in patients with AD. The most remarkable reduction in TLR2-mediated proinflammatory cytokine production was observed in CD14(dim) monocytes expressing high FcvarepsilonRI levels from patients with AD. This reduction was restored by means of downregulation of their FcvarepsilonRI expression after preculture in the absence of IgE. CONCLUSION Monocytes, particularly the proinflammatory monocytes, from patients with AD are functionally defective in their capacity to produce proinflammatory cytokines on TLR2 stimuli in part because of the high levels of their FcvarepsilonRI expression. CLINICAL IMPLICATIONS This selective impairment of monocytes would explain why patients with AD are specifically susceptible to cutaneous staphylococcal and streptococcal and HSV infections.
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Affiliation(s)
- Habib Hasannejad
- Department of Dermatology, Kyorin University School of Medicine, Tokyo, Japan
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Abstract
Tumors arise from normal cells of the body through genetic mutation. Although such genetic mutation often leads to the expression of abnormal antigens, the immune system fails to respond effectively to these antigens; that is, it is tolerant of these antigens. This acquired state of tolerance must be overcome for cancer immunotherapy to succeed. Indoleamine 2,3-dioxygenase (IDO) is one molecular mechanism that contributes to tumor-induced tolerance. IDO helps create a tolerogenic milieu in the tumor and the tumor-draining lymph nodes, both by direct suppression of T cells and enhancement of local Treg-mediated immunosuppression. It can also function as an antagonist to other activators of antitumor immunity. Therefore, strategies to block IDO might enhance the effectiveness of tumor immunotherapy.
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Affiliation(s)
- David H Munn
- Immunotherapy Program, Department of Pediatrics, MCG Cancer Center, Medical College of Georgia, Augusta, GA 30912, USA.
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47
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Bieber T. The pro- and anti-inflammatory properties of human antigen-presenting cells expressing the high affinity receptor for IgE (FcεRI). Immunobiology 2007; 212:499-503. [PMID: 17544834 DOI: 10.1016/j.imbio.2007.03.001] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2007] [Accepted: 03/01/2007] [Indexed: 11/18/2022]
Abstract
Almost 20 years after the first description of IgE on the surface of epidermal Langerhans cells (LC) and the subsequent characterization of the trimeric Fc epsilon RI on human antigen-presenting cells (APC), we have gained profound insights into the receptor responsible for this binding. Fc epsilon RI may act as a pro-inflammatory structure on some APC such as inflammatory dendritic epidermal cells (IDEC) in the skin of patients with atopic dermatitis while it can also be an important instrument in mechanisms leading to tolerance on other APC such as LC of the oral mucosa. By virtue of Fc epsilon RI, APC can initiate inflammation by secretion of a wide spectrum of pro-inflammatory cytokines and chemokines. Fc epsilon RI+DC can induce either Th2 or Th1 profile in T-cells. In contrast, the production of the tryptophan-catabolizing enzyme indoleamine 2,3-dioxygenase (IDO) as well as IL-10 and TGFss may contribute to the tolerogenic properties of DC.
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Affiliation(s)
- Thomas Bieber
- Department of Dermatology and Allergy, University of Bonn, Sigmund-Freud-Street 25, 53105 Bonn, Germany.
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48
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Mahanonda R, Sa-Ard-Iam N, Montreekachon P, Pimkhaokham A, Yongvanichit K, Fukuda MM, Pichyangkul S. IL-8 and IDO expression by human gingival fibroblasts via TLRs. THE JOURNAL OF IMMUNOLOGY 2007; 178:1151-7. [PMID: 17202379 DOI: 10.4049/jimmunol.178.2.1151] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Human gingival fibroblasts (HGFs), a predominant cell type in tooth-supporting structure, are presently recognized for their active role in the innate immune response. They produce a variety of inflammatory cytokines in response to microbial components such as LPS from the key periodontal pathogen, Porphyromonas gingivalis. In this study, we demonstrated that HGFs expressed mRNA of TLRs 1, 2, 3, 4, 5, 6, and 9, but not TLRs 7, 8, and 10. Stimulation of HGFs with highly purified TLR2 ligand (P. gingivalis LPS), TLR3 ligand (poly(I:C)), TLR4 ligand (Escherichia coli LPS), and TLR5 ligand (Salmonella typhimurium flagellin) led to expression of IL-8 and IDO. A potent TLR 9 ligand, CpG oligodeoxynucleotide 2006 had no effect, although HGFs showed a detectable TLR9 mRNA expression. No significant enhancement on IL-8 or IDO expression was observed when HGFs were stimulated with various combinations of TLR ligands. Surprisingly, the TLR9 ligand CpG oligodeoxynucleotide 2006 was able to specifically inhibit poly(I:C)-induced IL-8 and IDO expression. TNF-alpha enhanced TLR ligand-induced IL-8 production in HGFs, whereas IFN-gamma enhanced TLR ligand-induced IDO expression. HGF production of IDO in response to P. gingivalis LPS, IFN-gamma, or the two in combination inhibited T cell proliferation in MLRs. The observed T cell inhibition could be reversed by addition of either 1-methyl-dl-tryptophan or l-tryptophan. Our results suggest an important role of HGFs not only in orchestrating the innate immune response, but also in dampening potentially harmful hyperactive inflammation in periodontal tissue.
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Affiliation(s)
- Rangsini Mahanonda
- Department of Periodontology, Faculty of Dentistry, Chulalongkorn University, Henry Dunant Road, Bangkok, Thailand.
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49
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Abstract
Allergen immunotherapy is a well-established strategy for treating allergic diseases with the goal of inducing allergen-specific tolerance. Identified mechanisms contributing to the therapeutic effect of immunotherapy include a shift of T helper 2 (Th2)-type immune responses to a modified Th2 immune response, a change of the balance of IgE-producing B cells to the production of IgG subtypes, in addition to increased IL-10 and TGF-beta secretion and activation of the suppressive functions of regulatory T-cells. Dendritic cells (DCs), which as outposts of the immune system are capable of T-cell priming through efficient allergen uptake by IgE receptors expressed on their cell surface. Most of the hypotheses concerning the function of DCs as facilitators of allergen-specific tolerance in allergen immunotherapy remain speculative. Therefore, studies must focus on the functional changes of DCs under immunotherapy to close the gap of knowledge about their exact role. These experimental data should help confirm the hypothesis of DCs as efficient silencers and potential target cells and take advantage of the bivalent character and tolerogenic properties of DCs.
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Affiliation(s)
- Natalija Novak
- Department of Dermatology, University of Bonn, Sigmund-Freud-Strasse 25, 53105 Bonn, Germany.
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50
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Le AV, Broide DH. Indoleamine-2,3-dioxygenase modulation of allergic immune responses. Curr Allergy Asthma Rep 2006; 6:27-31. [PMID: 16476191 DOI: 10.1007/s11882-006-0006-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Induction of immunologic tolerance is highly desirable in the treatment and prevention of allergy and other immune disease states in which the immune response to foreign or self antigens has become overactive. Indoleamine-2,3-dioxygenase (IDO), an enzyme classically known for its role in the tryptophan degradation pathway, has recently emerged as an important immunomodulator of T-cell function and inducer of tolerance. The induced expression of IDO by dendritic cells may suppress T-cell responses and promote tolerance either through direct effects on T cells (mediated by tryptophan depletion or tryptophan metabolites) or through effects of IDO on the dendritic cell. In addition to the potential role of IDO in promoting tolerance in pregnancy, transplantation, and autoimmunity, its role in modulating allergic responses has more recently been investigated, raising the possibility that IDO and its metabolites may be novel targets for immunomodulation in allergy and asthma.
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Affiliation(s)
- Annie V Le
- Department of Medicine, University of California, San Diego, 9500 Gilman Drive, MC 0635, La Jolla, CA 92093, USA
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