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Raynor JL, Chi H. Nutrients: Signal 4 in T cell immunity. J Exp Med 2024; 221:e20221839. [PMID: 38411744 PMCID: PMC10899091 DOI: 10.1084/jem.20221839] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Revised: 01/30/2024] [Accepted: 02/02/2024] [Indexed: 02/28/2024] Open
Abstract
T cells are integral in mediating adaptive immunity to infection, autoimmunity, and cancer. Upon immune challenge, T cells exit from a quiescent state, followed by clonal expansion and effector differentiation. These processes are shaped by three established immune signals, namely antigen stimulation (Signal 1), costimulation (Signal 2), and cytokines (Signal 3). Emerging findings reveal that nutrients, including glucose, amino acids, and lipids, are crucial regulators of T cell responses and interplay with Signals 1-3, highlighting nutrients as Signal 4 to license T cell immunity. Here, we first summarize the functional importance of Signal 4 and the underlying mechanisms of nutrient transport, sensing, and signaling in orchestrating T cell activation and quiescence exit. We also discuss the roles of nutrients in programming T cell differentiation and functional fitness and how nutrients can be targeted to improve disease therapy. Understanding how T cells respond to Signal 4 nutrients in microenvironments will provide insights into context-dependent functions of adaptive immunity and therapeutic interventions.
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Affiliation(s)
- Jana L Raynor
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Hongbo Chi
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN, USA
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Dacic M, Shibu G, Rogatsky I. Physiological Convergence and Antagonism Between GR and PPARγ in Inflammation and Metabolism. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1390:123-141. [PMID: 36107316 DOI: 10.1007/978-3-031-11836-4_7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Nuclear receptors (NRs) are transcription factors that modulate gene expression in a ligand-dependent manner. The ubiquitously expressed glucocorticoid receptor (GR) and peroxisome proliferator-activated receptor gamma (PPARγ) represent steroid (type I) and non-steroid (type II) classes of NRs, respectively. The diverse transcriptional and physiological outcomes of their activation are highly tissue-specific. For example, in subsets of immune cells, such as macrophages, the signaling of GR and PPARγ converges to elicit an anti-inflammatory phenotype; in contrast, in the adipose tissue, their signaling can lead to reciprocal metabolic outcomes. This review explores the cooperative and divergent outcomes of GR and PPARγ functions in different cell types and tissues, including immune cells, adipose tissue and the liver. Understanding the coordinated control of these NR pathways should advance studies in the field and potentially pave the way for developing new therapeutic approaches to exploit the GR:PPARγ crosstalk.
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Affiliation(s)
- Marija Dacic
- Hospital for Special Surgery Research Institute, The David Rosenzweig Genomics Center, New York, NY, USA
- Graduate Program in Physiology, Biophysics and Systems Biology, Weill Cornell Graduate School of Medical Sciences, New York, NY, USA
| | - Gayathri Shibu
- Hospital for Special Surgery Research Institute, The David Rosenzweig Genomics Center, New York, NY, USA
- Graduate Program in Immunology and Microbial Pathogenesis, Weill Cornell Graduate School of Medical Sciences, New York, NY, USA
| | - Inez Rogatsky
- Hospital for Special Surgery Research Institute, The David Rosenzweig Genomics Center, New York, NY, USA.
- Graduate Program in Immunology and Microbial Pathogenesis, Weill Cornell Graduate School of Medical Sciences, New York, NY, USA.
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Porcuna J, Mínguez-Martínez J, Ricote M. The PPARα and PPARγ Epigenetic Landscape in Cancer and Immune and Metabolic Disorders. Int J Mol Sci 2021; 22:ijms221910573. [PMID: 34638914 PMCID: PMC8508752 DOI: 10.3390/ijms221910573] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Revised: 09/27/2021] [Accepted: 09/28/2021] [Indexed: 02/07/2023] Open
Abstract
Peroxisome proliferator-activated receptors (PPARs) are ligand-modulated nuclear receptors that play pivotal roles in nutrient sensing, metabolism, and lipid-related processes. Correct control of their target genes requires tight regulation of the expression of different PPAR isoforms in each tissue, and the dysregulation of PPAR-dependent transcriptional programs is linked to disorders, such as metabolic and immune diseases or cancer. Several PPAR regulators and PPAR-regulated factors are epigenetic effectors, including non-coding RNAs, epigenetic enzymes, histone modifiers, and DNA methyltransferases. In this review, we examine advances in PPARα and PPARγ-related epigenetic regulation in metabolic disorders, including obesity and diabetes, immune disorders, such as sclerosis and lupus, and a variety of cancers, providing new insights into the possible therapeutic exploitation of PPAR epigenetic modulation.
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Metabolic coordination of T cell quiescence and activation. Nat Rev Immunol 2019; 20:55-70. [DOI: 10.1038/s41577-019-0203-y] [Citation(s) in RCA: 223] [Impact Index Per Article: 44.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/15/2019] [Indexed: 02/07/2023]
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Chapman NM, Shrestha S, Chi H. Metabolism in Immune Cell Differentiation and Function. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1011:1-85. [PMID: 28875486 DOI: 10.1007/978-94-024-1170-6_1] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The immune system is a central determinant of organismal health. Functional immune responses require quiescent immune cells to rapidly grow, proliferate, and acquire effector functions when they sense infectious agents or other insults. Specialized metabolic programs are critical regulators of immune responses, and alterations in immune metabolism can cause immunological disorders. There has thus been growing interest in understanding how metabolic processes control immune cell functions under normal and pathophysiological conditions. In this chapter, we summarize how metabolic programs are tuned and what the physiological consequences of metabolic reprogramming are as they relate to immune cell homeostasis, differentiation, and function.
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Affiliation(s)
- Nicole M Chapman
- Department of Immunology, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN, 38105, USA
| | - Sharad Shrestha
- Department of Immunology, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN, 38105, USA
| | - Hongbo Chi
- Department of Immunology, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN, 38105, USA.
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Park HJ, Choi JM. Sex-specific regulation of immune responses by PPARs. Exp Mol Med 2017; 49:e364. [PMID: 28775365 PMCID: PMC5579504 DOI: 10.1038/emm.2017.102] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Revised: 02/15/2017] [Accepted: 03/05/2017] [Indexed: 12/18/2022] Open
Abstract
The prevalence of autoimmune, infectious and metabolic diseases is different for men and women owing to the respective ability of their immune systems to respond to self and foreign antigens. Although several factors, including hormones and the X-chromosome, have been suggested to contribute to such sex-specific immune responses, the underlying factors remain poorly defined. Recent studies using peroxisome proliferator-activated receptor (PPAR) ligands and knockout mice have identified sex-dimorphic expression of PPARs, and have shown that the inhibitory functions of PPAR in T cells are substantially affected by the sex hormones. In this review, we consider the sex-specific differences in PPARs and summarize the diverse PPAR-mediated, sex-specific properties of effector T-cell responses, such as T-cell activation, survival and differentiation, as well as their involvement in T-cell-related autoimmune diseases, including colitis, graft-versus-host disease and experimental autoimmune encephalomyelitis. Understanding PPAR-mediated sex differences in immune responses will provide more precise insights into the roles of PPARs in effector T cells.
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Affiliation(s)
- Hong-Jai Park
- Department of Life Science, College of Natural Sciences, Hanyang University, Seoul, Republic of Korea.,Research Institute for Natural Sciences, Hanyang University, Seoul, Republic of Korea
| | - Je-Min Choi
- Department of Life Science, College of Natural Sciences, Hanyang University, Seoul, Republic of Korea.,Research Institute for Natural Sciences, Hanyang University, Seoul, Republic of Korea
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Zhang Y, Li X, Fang S, Zhu Z, Yao M, Ying L, Zhu L, Ma Z, Wang W. Peroxisome proliferator-activated receptor γ agonist suppresses mast cell maturation and induces apoptosis. Mol Med Rep 2017; 16:1793-1800. [PMID: 28656266 PMCID: PMC5562075 DOI: 10.3892/mmr.2017.6802] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2016] [Accepted: 06/08/2017] [Indexed: 01/15/2023] Open
Abstract
Peroxisome proliferator-activated receptor gamma (PPAR γ), is important in the immunoregulation of the allergic response. Mast cells are the most important inflammatory cells in immediate hypersensitivity and allergic diseases. However, there is limited information regarding the effects of PPAR γ on mast cell maturation. In the present study, mouse bone marrow-derived mast cells (BMMCs) were cultured in interleukin (IL)-3 and stem cell factor (SCF), in the presence or absence of the PPAR γ agonist, pioglitazone (PIO). The expression levels of the tyrosine kinase receptor CD117 and the high affinity IgE receptor FcεRI α, were assessed by flow cytometry, cell viability was assessed by Alamar-Blue assay and histamine release was determined by measuring the activity of β-hexosaminidase. IL-3 and SCF are required for the development of mast cells in vitro. PIO dose-dependently inhibited the expression of CD117 and FcεRI α, and the maturation of BMMCs. Treatment with PIO additionally inhibited the formation of granules and reduced the expression of β-hexosaminidase. In addition, reverse transcription-polymerase chain reaction analysis revealed that BMMCs treated with PIO expressed a lower level of mast cell protease (MCP)-6 mRNA and PIO treatment enhanced the level of PPAR γ mRNA. Furthermore, PIO induced mast cell progenitor apoptosis. PPAR γ agonists may maintain mast cell homeostasis by inhibiting maturation of their precursors. The inhibitory effects of PPAR γ agonists include suppression of the activation of mast cells and a decrease in mast cell function in the inflammatory response. Therefore, PPAR γ agonists may serve as effective anti-inflammatory reagents in the treatment of allergic reactions.
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Affiliation(s)
- Yu Zhang
- Department of Otolaryngology‑Head and Neck Surgery, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, P.R. China
| | - Xinqian Li
- Department of Otolaryngology‑Head and Neck Surgery, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, P.R. China
| | - Shengjian Fang
- Department of Otolaryngology‑Head and Neck Surgery, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, P.R. China
| | - Zhenghua Zhu
- Department of Otolaryngology‑Head and Neck Surgery, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, P.R. China
| | - Min Yao
- Department of Otolaryngology‑Head and Neck Surgery, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, P.R. China
| | - Liyun Ying
- Department of Otolaryngology‑Head and Neck Surgery, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, P.R. China
| | - Liwei Zhu
- Department of Otolaryngology‑Head and Neck Surgery, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, P.R. China
| | - Zhaoxin Ma
- Department of Otolaryngology‑Head and Neck Surgery, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, P.R. China
| | - Weihua Wang
- Department of Otolaryngology‑Head and Neck Surgery, Shanghai East Hospital, Tongji University School of Medicine, Shanghai 200120, P.R. China
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Wei J, Raynor J, Nguyen TLM, Chi H. Nutrient and Metabolic Sensing in T Cell Responses. Front Immunol 2017; 8:247. [PMID: 28337199 PMCID: PMC5343023 DOI: 10.3389/fimmu.2017.00247] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Accepted: 02/20/2017] [Indexed: 12/13/2022] Open
Abstract
T cells play pivotal roles in shaping host immune responses in infectious diseases, autoimmunity, and cancer. The activation of T cells requires immune and growth factor-derived signals. However, alterations in nutrients and metabolic signals tune T cell responses by impinging upon T cell fates and immune functions. In this review, we summarize how key nutrients, including glucose, amino acids, and lipids, and their sensors and transporters shape T cell responses. We also briefly discuss regulation of T cell responses by oxygen and energy sensing mechanisms.
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Affiliation(s)
- Jun Wei
- Department of Immunology, St. Jude Children's Research Hospital , Memphis, TN , USA
| | - Jana Raynor
- Department of Immunology, St. Jude Children's Research Hospital , Memphis, TN , USA
| | - Thanh-Long M Nguyen
- Department of Immunology, St. Jude Children's Research Hospital , Memphis, TN , USA
| | - Hongbo Chi
- Department of Immunology, St. Jude Children's Research Hospital , Memphis, TN , USA
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Ponath G, Ramanan S, Mubarak M, Housley W, Lee S, Sahinkaya FR, Vortmeyer A, Raine CS, Pitt D. Myelin phagocytosis by astrocytes after myelin damage promotes lesion pathology. Brain 2016; 140:399-413. [PMID: 28007993 DOI: 10.1093/brain/aww298] [Citation(s) in RCA: 140] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Revised: 10/14/2016] [Accepted: 10/17/2016] [Indexed: 12/20/2022] Open
Abstract
Astrocytes are key players in the pathology of multiple sclerosis and can assume beneficial and detrimental roles during lesion development. The triggers and timing of the different astroglial responses in acute lesions remain unclear. Astrocytes in acute multiple sclerosis lesions have been shown previously to contain myelin debris, although its significance has not been examined. We hypothesized that myelin phagocytosis by astrocytes is an early event during lesion formation and leads to astroglial immune responses. We examined multiple sclerosis lesions and other central nervous system pathologies with prominent myelin injury, namely, progressive multifocal leukoencephalopathy, metachromatic leukodystrophy and subacute infarct. In all conditions, we found that myelin debris was present in most astrocytes at sites of acute myelin breakdown, indicating that astroglial myelin phagocytosis is an early and prominent feature. Functionally, myelin debris was taken up by astrocytes through receptor-mediated endocytosis and resulted in astroglial NF-κB activation and secretion of chemokines. These in vitro results in rats were validated in human disease where myelin-positive hypertrophic astrocytes showed increased nuclear localization of NF-κB and elevated chemokine expression compared to myelin-negative, reactive astrocytes. Thus, our data suggest that myelin uptake is an early response of astrocytes in diseases with prominent myelin injury that results in recruitment of immune cells. This first line response of astrocytes to myelin injury may exert beneficial or detrimental effects on the lesion pathology, depending on the inflammatory context. Modulating this response might be of therapeutic relevance in multiple sclerosis and other demyelinating conditions.
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Affiliation(s)
- Gerald Ponath
- Yale University, School of Medicine, Department of Neurology, 300 George St, New Haven, CT 06511, USA
| | - Sriram Ramanan
- Yale University, School of Medicine, Department of Neurology, 300 George St, New Haven, CT 06511, USA
| | - Mayyan Mubarak
- Yale University, School of Medicine, Department of Neurology, 300 George St, New Haven, CT 06511, USA
| | - William Housley
- Yale University, School of Medicine, Department of Neurology, 300 George St, New Haven, CT 06511, USA
| | - Seunghoon Lee
- Yale University, School of Medicine, Department of Ophthalmology and Visual Science, 300 George St, New Haven, CT 06511, USA
| | - F Rezan Sahinkaya
- The Ohio State University College of Medicine, Department of Neuroscience, 670 Biomedical Research Tower, Columbus, OH, 43210, USA
| | - Alexander Vortmeyer
- Yale University, School of Medicine, Department of Pathology, 310 Cedar Street New Haven, CT 06520-8023, USA
| | - Cedric S Raine
- Albert Einstein College of Medicine, Department of Pathology (Neuropathology), 1300 Morris Park Avenue, Bronx, NY 10461, USA
| | - David Pitt
- Yale University, School of Medicine, Department of Neurology, 300 George St, New Haven, CT 06511, USA
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Scharping NE, Delgoffe GM. Tumor Microenvironment Metabolism: A New Checkpoint for Anti-Tumor Immunity. Vaccines (Basel) 2016; 4:E46. [PMID: 27929420 PMCID: PMC5192366 DOI: 10.3390/vaccines4040046] [Citation(s) in RCA: 75] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2016] [Revised: 11/01/2016] [Accepted: 11/25/2016] [Indexed: 12/21/2022] Open
Abstract
When a T cell infiltrates a tumor, it is subjected to a variety of immunosuppressive and regulatory signals in the microenvironment. However, it is becoming increasingly clear that due to the proliferative and energetically-deregulated nature of tumor cells, T cells also operate at a metabolic disadvantage. The nutrient dearth of the tumor microenvironment (TME) creates "metabolic checkpoints" upon infiltrating T cells, impacting their ability to survive, proliferate and function effectively. In this review, we summarize the basics of tumor cell and T cell metabolism and discuss recent advances elucidating the individual metabolic checkpoints exerted on T cells that drive their dysfunction in the TME.
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Affiliation(s)
- Nicole E Scharping
- Tumor Microenvironment Center, University of Pittsburgh Cancer Institute, Pittsburgh, PA 15232, USA.
- Department of Immunology, University of Pittsburgh, Pittsburgh, PA 15213, USA.
| | - Greg M Delgoffe
- Tumor Microenvironment Center, University of Pittsburgh Cancer Institute, Pittsburgh, PA 15232, USA.
- Department of Immunology, University of Pittsburgh, Pittsburgh, PA 15213, USA.
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Fatty acid metabolic reprogramming via mTOR-mediated inductions of PPARγ directs early activation of T cells. Nat Commun 2016; 7:13683. [PMID: 27901044 PMCID: PMC5141517 DOI: 10.1038/ncomms13683] [Citation(s) in RCA: 160] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Accepted: 10/25/2016] [Indexed: 12/15/2022] Open
Abstract
To fulfil the bioenergetic requirements for increased cell size and clonal expansion, activated T cells reprogramme their metabolic signatures from energetically quiescent to activated. However, the molecular mechanisms and essential components controlling metabolic reprogramming in T cells are not well understood. Here, we show that the mTORC1–PPARγ pathway is crucial for the fatty acid uptake programme in activated CD4+ T cells. This pathway is required for full activation and rapid proliferation of naive and memory CD4+ T cells. PPARγ directly binds and induces genes associated with fatty acid uptake in CD4+ T cells in both mice and humans. The PPARγ-dependent fatty acid uptake programme is critical for metabolic reprogramming. Thus, we provide important mechanistic insights into the metabolic reprogramming mechanisms that govern the expression of key enzymes, fatty acid metabolism and the acquisition of an activated phenotype during CD4+ T cell activation. PPARγ promotes free fatty acid uptake and also has a role in T cell regulation. Here the authors show that mTORC1-PPARγ signalling is needed for fatty acid uptake by activated CD4+ T cells and for clonal expansion of these cells.
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Park HJ, Park HS, Lee JU, Bothwell ALM, Choi JM. Sex-Based Selectivity of PPARγ Regulation in Th1, Th2, and Th17 Differentiation. Int J Mol Sci 2016; 17:ijms17081347. [PMID: 27548145 PMCID: PMC5000743 DOI: 10.3390/ijms17081347] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Revised: 08/03/2016] [Accepted: 08/11/2016] [Indexed: 12/13/2022] Open
Abstract
Peroxisome proliferator-activated receptor gamma (PPARγ) has recently been recognized to regulate adaptive immunity through Th17 differentiation, Treg functions, and TFH responses. However, its role in adaptive immunity and autoimmune disease is still not clear, possibly due to sexual differences. Here, we investigated in vitro treatment study with the PPARγ agonist pioglitazone to compare Th1, Th2, and Th17 differentiation in male and female mouse splenic T cells. Pioglitazone treatment significantly inhibited various effector T cell differentiations including Th1, Th2, and Th17 cells from female naïve T cells, but it selectively reduced IL-17 production in male Th17 differentiation. Interestingly, pioglitazone and estradiol (E2) co-treatment of T cells in males inhibited differentiation of Th1, Th2, and Th17 cells, suggesting a mechanism for the greater sensitivity of PPARγ to ligand treatment in the regulation of effector T cell differentiation in females. Collectively, these results demonstrate that PPARγ selectively inhibits Th17 differentiation only in male T cells and modulates Th1, Th2, and Th17 differentiation in female T cells based on different level of estrogen exposure. Accordingly, PPARγ could be an important immune regulator of sexual differences in adaptive immunity.
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Affiliation(s)
- Hong-Jai Park
- Department of Life Science, College of Natural Sciences, Hanyang University, Seoul 04763, Korea.
- Research Institute for Natural Sciences, Hanyang University, Seoul 04763, Korea.
| | - Hyeon-Soo Park
- Department of Life Science, College of Natural Sciences, Hanyang University, Seoul 04763, Korea.
- Research Institute for Natural Sciences, Hanyang University, Seoul 04763, Korea.
| | - Jae-Ung Lee
- Department of Life Science, College of Natural Sciences, Hanyang University, Seoul 04763, Korea.
- Research Institute for Natural Sciences, Hanyang University, Seoul 04763, Korea.
| | - Alfred L M Bothwell
- Department of Immunobiology, Yale University School of Medicine, New Haven, CT 06520, USA.
| | - Je-Min Choi
- Department of Life Science, College of Natural Sciences, Hanyang University, Seoul 04763, Korea.
- Research Institute for Natural Sciences, Hanyang University, Seoul 04763, Korea.
- Center for Neuroscience Imaging Research (CNIR), Institute for Basic Science (IBS), Suwon 16419, Korea.
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Gender-specific differences in PPARγ regulation of follicular helper T cell responses with estrogen. Sci Rep 2016; 6:28495. [PMID: 27335315 PMCID: PMC4917844 DOI: 10.1038/srep28495] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Accepted: 06/03/2016] [Indexed: 11/21/2022] Open
Abstract
Peroxisome proliferator-activated receptor gamma (PPARγ), a master regulator of adipocyte differentiation, has recently been connected with effector T cells, though its role is still not clear. Here, we investigated the roles of PPARγ in follicular helper T (TFH) cell responses regarding gender specificity. NP-OVA immunization in female but not male CD4-PPARγKO mice induced higher proportions of TFH cells and germinal center (GC) B cells following immunization than were seen in wild type mice. Treatment with the PPARγ agonist pioglitazone significantly reduced TFH cell responses in female mice while pioglitazone and estradiol (E2) co-treatment ameliorated TFH cells and GC responses in male mice. E2 treatment significantly enhanced PPARγ expression in male T cells, while T cell activation in the estrus but not in the diestrus stage of the menstrual cycle of females was inhibited by pioglitazone, suggesting that an estrogen-sufficient environment is important for PPARγ-mediated T cell regulation. These results demonstrate gender-based differences in sensitivities of PPARγ in TFH responses. These findings suggest that appropriate function of PPARγ is required in the regulation of female GC responses and that therapeutic strategies for autoimmune diseases using PPARγ agonists need to be tailored accordingly.
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Yuan M, Qiu M, Cui J, Zhang X, Zhang P. Protective effects of pioglitazone against immunoglobulin deposition on heart of streptozotocin-induced diabetic rats. J Endocrinol Invest 2014; 37:375-84. [PMID: 24682915 DOI: 10.1007/s40618-013-0046-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Accepted: 12/17/2013] [Indexed: 11/28/2022]
Abstract
AIM Peroxisome proliferator-activated receptor-γ (PPAR-γ) agonists have immunomodulatory and anti-inflammatory effects. The study investigated the autoimmune injuries of diabetic cardiomyopathy (DCM) and tested the hypothesis that PPAR-γ agonists suppress disordered immune responses in diabetic heart, thereby preventing evolution of DCM. METHODS STZ-induced diabetic rats were assigned to five groups: DM group, given no treatment; INS group, given insulin (4 U kg(-1) d(-1)); PIL group, given low dose pioglitazone (4 mg kg(-1) d(-1)); PIL/INS group, given both low dose pioglitazone and insulin; PIH group, given high dose pioglitazone (20 mg kg(-1) d(-1)). Normal rats (CON group) were also monitored as control. The pathologic abnormalities of hearts were observed. The immunoglobulin deposition was examined by immunohistochemistry and immunofluorescence. RESULTS At 16 weeks, interstitial fibrosis was shown in diabetic heart which was accompanied by plenty of inflammatory cells infiltrated. Pioglitazone therapy could ameliorate the cardiac injuries. Shown by immunohistochemistry, the difference of integrated optical density (IOD) of immunoglobulin deposition among each group had statistic significance. No obvious immunoglobulins were deposited in the intercellular substance of heart in CON group (IgA 290.8 ± 88.1, IgG 960.4 ± 316.0 and IgM 341.3 ± 67.9). But the deposition of immunoglobulins increased significantly in DM group (IgA 7,047.5 ± 1,328.3, P < 0.05; IgG 28,945.9 ± 5,160.7, P < 0.05 and IgM 8,580.8 ± 1,336.8, P < 0.05). Administration of pioglitazone greatly reduced the increased deposition in a dose-dependent fashion. Moreover, the statistical significance was the same with immunofluorescence analysis as with immunohistochemical examination. CONCLUSIONS The data suggest that disordered immune responses play an important role in the pathogenesis of DCM. Pioglitazone showed protective effects by inhibiting the immunoglobulin deposition on diabetic myocardium.
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Affiliation(s)
- M Yuan
- Department of Endocrinology, General Hospital of Tianjin Medical University, Tianjin, 300052, China
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Abstract
The initiation and perpetuation of autoimmunity recognize numerous checkpoints, from the genomic susceptibility to the breakdown of tolerance. This latter phenomenon includes the loss of B cell anergy and T regulatory cell failure, as well as the production of autoantibodies and autoreactive T cells. These mechanisms ultimately lead to tissue injury via different mechanisms that span from the production of proinflammatory cytokines to the chemotaxis of immune cells to the target sites. The pathways to autoimmunity have been widely investigated over the past year and resulted in a number of articles in peer-reviewed journals that has increased by nearly 10 % compared to 2011. We herein follow on the attempt to provide a brief discussion of the majority of articles on autoimmune diseases that were published in the major immunology journals in the previous solar year. The selection is necessarily arbitrary and may thus not be seen as comprehensive but reflects current research trends. Indeed, 2012 articles were mostly dedicated to define new and old mechanisms with potential therapeutic implications in autoimmunity in general, though based on specific clinical conditions or animal models. As paradigmatic examples, the environmental influence on autoimmunity, Th17 changes modulating the autoimmune response, serum autoantibodies and B cell changes as biomarkers and therapeutic targets were major issues addressed by experimental articles in 2012. Further, a growing number of studies investigated the sex bias of autoimmunity and supported different working hypotheses to explain the female predominance, including sex chromosome changes and reproductive life factors. In conclusion, the resulting scenario illustrates that common factors may underlie different autoimmune diseases and this is well represented by the observed alterations in interferon-α and TGFβ or by the shared signaling pathways.
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Affiliation(s)
- Carlo Selmi
- Department of Medical Biotechnology and Translational Medicine, University of Milan, Milan, Italy,
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The survival role of peroxisome proliferator-activated receptor gamma induces odontoblast differentiation against oxidative stress in human dental pulp cells. J Endod 2014; 39:236-41. [PMID: 23321237 DOI: 10.1016/j.joen.2012.11.006] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2012] [Revised: 10/24/2012] [Accepted: 11/06/2012] [Indexed: 01/21/2023]
Abstract
INTRODUCTION Peroxisome proliferator-activated receptor gamma (PPARγ) has well-known anti-inflammatory action in human dental pulp cells (HDPCs). The purpose of this study was to investigate whether the anti-inflammatory action of PPARγ involves in cellular cytoprotection and supports odontoblast differentiation under oxidative stress in HDPCs. METHODS To simulate long-term oxidative stress, pulp cells were treated with 150 μmol hydrogen peroxide (H(2)O(2)) for 12 days. The replication deficiency adenovirus (adenovirus PPARγ) was introduced for PPARγ overexpression in pulp cells. The cellular cytotoxicity and reactive oxygen species formation by H(2)O(2) were determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide and 2',7'-dichlorodihydrofluorescein diacetate with fluorescence-activated cell sorting assay. To determine the roles of PPARγ, several molecules of odontogenic/osteogenic and signal pathway were analyzed by reverse-transcription polymerase chain reaction and Western hybridization. Dentin mineralization was determined by alizarin red stain and alkaline phosphatase activity assay. RESULTS Pulp cells treated with long-term H(2)O(2) showed high reactive oxygen species formation, low cell viability, down-expression of antioxidant molecules (Cu/Zn and Mn superoxide dismutase), and odontogenic/osteogenic markers (eg, dentin sialophosphoprotein, dentin matrix protein-1, osteopontin, bone sialoprotein, Runx-2, and bone morphogenetic protein 2 and 7). In addition, pulp cells with oxidative stress underwent the activation of ERK1/2, activator protein-1, and nuclear factor-κB translocation to the nucleus. However, the PPARγ-overexpressed cells gave opposite results although under oxidative stress. Furthermore, PPARγ and its agonist rosiglitazone exhibited an induction of dentin mineralization under oxidative stress. CONCLUSIONS PPARγ in pulp cells increases cell viability, odontoblastic differentiation, and dentin mineralization under oxidative stress. These results offer new insights into the potential antioxidative activity of PPARγ and its agonist for therapeutic agents for pulp vitality in HDPCs.
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PPARγ Agonists in Adaptive Immunity: What Do Immune Disorders and Their Models Have to Tell Us? PPAR Res 2013; 2013:519724. [PMID: 23983678 PMCID: PMC3747405 DOI: 10.1155/2013/519724] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2013] [Revised: 06/17/2013] [Accepted: 06/27/2013] [Indexed: 01/25/2023] Open
Abstract
Adaptive immunity has evolved as a very powerful and highly specialized tool of host defense. Its classical protagonists are lymphocytes of the T- and B-cell lineage. Cytokines and chemokines play a key role as effector mechanisms of the adaptive immunity. Some autoimmune and inflammatory diseases are caused by disturbance of the adaptive immune system. Recent advances in understanding the pathogenesis of autoimmune diseases have led to research on new molecular and therapeutic targets. PPARγ are members of the nuclear receptor superfamily and are transcription factors involved in lipid metabolism as well as innate and adaptive immunity. PPARγ is activated by synthetic and endogenous ligands. Previous studies have shown that PPAR agonists regulate T-cell survival, activation and T helper cell differentiation into effector subsets: Th1, Th2, Th17, and Tregs. PPARγ has also been associated with B cells. The present review addresses these issues by placing PPARγ agonists in the context of adaptive immune responses and the relation of the activation of these receptors with the expression of cytokines involved in adaptive immunity.
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Abstract
The interplay of the immune system with other aspects of physiology is continually being revealed and in some cases studied in considerable mechanistic detail. A prime example is the influence of metabolic cues on immune responses. It is well appreciated that upon activation, T cells take on a metabolic profile profoundly distinct from that of their quiescent and anergic counterparts; however, a number of recent breakthroughs have greatly expanded our knowledge of how aspects of cellular metabolism can shape a T-cell response. Particularly important are findings that certain environmental cues can tilt the delicate balance between inflammation and immune tolerance by skewing T-cell fate decisions toward either the T-helper 17 (Th17) or T-regulatory (Treg) cell lineage. Recognizing the unappreciated immune-modifying potential of metabolic factors and particularly those involved in the generation of these functionally opposing T-cell subsets will likely add new and potent therapies to our repertoire for treating immune mediated pathologies. In this review, we summarize and discuss recent findings linking certain metabolic pathways, enzymes, and by-products to shifts in the balance between Th17 and Treg cell populations. These advances highlight numerous opportunities for immune modulation.
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Affiliation(s)
- Joseph Barbi
- Department of Oncology, Immunology and Hematopoiesis Division, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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Waickman AT, Powell JD. mTOR, metabolism, and the regulation of T-cell differentiation and function. Immunol Rev 2013; 249:43-58. [PMID: 22889214 DOI: 10.1111/j.1600-065x.2012.01152.x] [Citation(s) in RCA: 301] [Impact Index Per Article: 27.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Upon antigen recognition, naive T cells undergo rapid expansion and activation. The energy requirements for this expansion are formidable, and T-cell activation is accompanied by dramatic changes in cellular metabolism. Furthermore, the outcome of antigen engagement is guided by multiple cues derived from the immune microenvironment. Mammalian target of rapamycin (mTOR) is emerging as a central integrator of these signals playing a critical role in driving T-cell differentiation and function. Indeed, multiple metabolic programs are controlled by mTOR signaling. In this review, we discuss the role of mTOR in regulating metabolism and how these pathways intersect with the ability of mTOR to integrate cues that guide the outcome of T-cell receptor engagement.
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Affiliation(s)
- Adam T Waickman
- Department of Oncology, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA
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20
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Abstract
The mechanisms leading to the onset and perpetuation of systemic and tissue-specific autoimmune diseases are complex, and numerous hypotheses have been proposed or confirmed over the past 12 months. It is particularly of note that the number of articles published during 2011 in the major immunology and autoimmunity journals increased by 3 % compared to the previous year. The present article is dedicated to a brief review of the reported data and, albeit not comprehensive of all articles, is aimed at identifying common and future themes. First, clinical researchers were particularly dedicated to defining refractory forms of diseases and to discuss the use and switch of therapeutic monoclonal antibodies in everyday practice. Second, following the plethora of genome-wide association studies reported in most multifactorial diseases, it became clear that genomics cannot fully explain the individual susceptibility and additional environmental or epigenetic factors are necessary. Both these components were widely investigated, both in organ-specific (i.e., type 1 diabetes) and systemic (i.e., systemic lupus erythematosus) diseases. Third, a large number of 2011 works published in the autoimmunity area are dedicated to dissect pathogenetic mechanisms of tolerance breakdown in general or in specific conditions. While our understanding of T regulatory and Th17 cells has significantly increased in 2011, it is of note that most of the proposed lines of evidence identify potential targets for future treatments and should not be overlooked.
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Choi JM, Bothwell AL. The nuclear receptor PPARs as important regulators of T-cell functions and autoimmune diseases. Mol Cells 2012; 33:217-22. [PMID: 22382683 PMCID: PMC3887706 DOI: 10.1007/s10059-012-2297-y] [Citation(s) in RCA: 114] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2011] [Revised: 01/22/2012] [Accepted: 02/09/2012] [Indexed: 01/12/2023] Open
Abstract
Members of the nuclear receptor superfamily function as transcription factors involved in innate and adaptive immunity as well as lipid metabolism. These highly conserved proteins participate in ligand-dependent or -independent regulatory mechanisms that affect gene expression. Peroxisome proliferator-activated receptors (PPARs), which include PPARα, PPARβ/δ, and PPARΓ, are a group of nuclear receptor proteins that play diverse roles in cellular differentiation, development, and metabolism. Each PPAR subfamily is activated by different endogenous and synthetic ligands. Recent studies using specific ligand treatments and cell type-specific PPAR knockout mice have revealed important roles for these proteins in T-cell-related autoimmune diseases. Moreover, PPARs have been shown to regulate T-cell survival, activation, and CD4(+) T helper cell differentiation into the Th1, Th2, Th17, and Treg lineages. Here, we review the studies that provide insight into the important regulatory roles of PPARs in T-cell activation, survival, proliferation, differentiation, and autoimmune disease.
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Affiliation(s)
- Je-Min Choi
- Department of Life Science, Research Institute for Natural Sciences, Hanyang Universtiy, Seoul 133-791,
Korea
- Hanyang Biomedical Research Institute, Hanyang Universtiy, Seoul 133-791,
Korea
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