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Abstract
Our understanding of epigenetics in complex diseases is rapidly advancing and increasingly influencing the practice of medicine. Much is known about disruption of chromatin-modifying enzymes in malignant disease, but knowledge of irregular epigenetics in immune-driven disorders is just emerging. Epigenetic factors, such as DNA or histone modifications, are indispensable for precise gene expression in diverse immune cell types. Thus a disruption of epigenetic landscapes likely has a large impact on immune homeostasis. Moreover, the low concordance rates for most autoimmune diseases suggest that epigenetics contribute to immune tolerance disturbance. Here we review the important role of epigenetics for initiation, maintenance, tolerance, and training of immune responses. We discuss evolving evidence that DNA/histone modifications and chromatin-modifying enzymes are altered in immune-based diseases. Furthermore, we explore the potential of small molecules targeting epigenetic machinery, some of which are already used in oncology, as a way to reset the immune response in disease.
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Burchfield JS, Li Q, Wang HY, Wang RF. JMJD3 as an epigenetic regulator in development and disease. Int J Biochem Cell Biol 2015; 67:148-57. [PMID: 26193001 DOI: 10.1016/j.biocel.2015.07.006] [Citation(s) in RCA: 96] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Revised: 07/13/2015] [Accepted: 07/15/2015] [Indexed: 02/06/2023]
Abstract
Gene expression is epigenetically regulated through DNA methylation and covalent chromatin modifications, such as acetylation, phosphorylation, ubiquitination, sumoylation, and methylation of histones. Histone methylation state is dynamically regulated by different groups of histone methyltransferases and demethylases. The trimethylation of histone 3 (H3K4) at lysine 4 is usually associated with the activation of gene expression, whereas trimethylation of histone 3 at lysine 27 (H3K27) is associated with the repression of gene expression. The polycomb repressive complex contains the H3K27 methyltransferase Ezh2 and controls dimethylation and trimethylation of H3K27 (H3K27me2/3). The Jumonji domain containing-3 (Jmjd3, KDM6B) and ubiquitously transcribed X-chromosome tetratricopeptide repeat protein (UTX, KDM6A) have been identified as H3K27 demethylases that catalyze the demethylation of H3K27me2/3. The role and mechanisms of both JMJD3 and UTX have been extensively studied for their involvement in development, cell plasticity, immune system, neurodegenerative disease, and cancer. In this review, we will focus on recent progresses made on understanding JMJD3 in the regulation of gene expression in development and diseases. This article is part of a Directed Issue entitled: Epigenetics dynamics in development and disease.
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Affiliation(s)
- Jana S Burchfield
- Center for Inflammation and Epigenetics, Houston Methodist Research Institute, Houston, TX 77030, USA
| | - Qingtian Li
- Department of Microbiology and Immunology, Weill Cornell Medical College, Cornell University, 1300 York Avenue, New York, NY 10065, USA
| | - Helen Y Wang
- Center for Inflammation and Epigenetics, Houston Methodist Research Institute, Houston, TX 77030, USA
| | - Rong-Fu Wang
- Center for Inflammation and Epigenetics, Houston Methodist Research Institute, Houston, TX 77030, USA; Department of Microbiology and Immunology, Weill Cornell Medical College, Cornell University, 1300 York Avenue, New York, NY 10065, USA.
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53
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Relle M, Foehr B, Schwarting A. Epigenetic Aspects of Systemic Lupus Erythematosus. Rheumatol Ther 2015; 2:33-46. [PMID: 27747498 PMCID: PMC4883254 DOI: 10.1007/s40744-015-0014-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Indexed: 12/31/2022] Open
Abstract
Autoimmune diseases such as systemic lupus erythematosus (SLE), rheumatoid arthritis, multiple sclerosis, autoimmune hepatitis, and inflammatory bowel disease have complex pathogeneses and the courses of events leading to these diseases are not well understood. The immune surveillance is a delicate balance between self and foreign as well as between tolerance and immune response. Exposure to certain environmental factors may impair this equilibrium, leading to autoimmune diseases, cancer, and the so-called “lifestyle diseases” such as atherosclerosis, heart attack, stroke, and obesity, among others. These external stimuli may also alter the epigenetic status quo and may trigger autoimmune diseases such as SLE in genetically susceptible individuals. This review aims to highlight the role of epigenetic (dys-)regulation in the pathogenesis of SLE.
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Affiliation(s)
- Manfred Relle
- Department of Medicine I, Mainz University Medical Center, Langenbeckstrasse 1, 55131, Mainz, Germany.
| | - Bernd Foehr
- Department of Medicine I, Mainz University Medical Center, Langenbeckstrasse 1, 55131, Mainz, Germany
| | - Andreas Schwarting
- Department of Medicine I, Mainz University Medical Center, Langenbeckstrasse 1, 55131, Mainz, Germany
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Hobeika E, Nielsen PJ, Medgyesi D. Signaling mechanisms regulating B-lymphocyte activation and tolerance. J Mol Med (Berl) 2015; 93:143-58. [PMID: 25627575 DOI: 10.1007/s00109-015-1252-8] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Revised: 12/15/2014] [Accepted: 12/25/2014] [Indexed: 01/01/2023]
Abstract
It is becoming more and more accepted that, in addition to producing autoantibodies, B lymphocytes have other important functions that influence the development of autoimmunity. For example, autoreactive B cells are able to produce inflammatory cytokines and activate pathogenic T cells. B lymphocytes can react to extracellular signals with a range of responses from anergy to autoreactivity. The final outcome is determined by the relative contribution of signaling events mediated by activating and inhibitory pathways. Besides the B cell antigen receptor (BCR), several costimulatory receptors expressed on B cells can also induce B cell proliferation and survival, or regulate antibody production. These include CD19, CD40, the B cell activating factor receptor, and Toll-like receptors. Hyperactivity of these receptors clearly contributes to breaking B-cell tolerance in several autoimmune diseases. Inhibitors of these activating signals (including protein tyrosine phosphatases, deubiquitinating enzymes and several adaptor proteins) are crucial to control B-cell activation and maintain B-cell tolerance. In this review, we summarize the inhibitory signaling mechanisms that counteract B-cell activation triggered by the BCR and the coreceptors.
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Affiliation(s)
- Elias Hobeika
- BIOSS Centre of Biological Signalling Studies, University of Freiburg and Department for Molecular Immunology, Faculty of Biology, University of Freiburg, 79104, Freiburg, Germany
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Abstract
Rheumatic disease is a large spectrum of heterogeneous conditions affecting the loco-motor system including joints, muscles, connective tissues, and soft tissues around the joints and bones. Many rheumatic diseases have an element of autoimmunity including systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA). Aberrant epigenetic regulation of gene expression is emerging as a major factor within rheumatic disease, and indicates potential new therapeutic avenues of approach to these debilitating conditions. Understanding the precise role of epigenetics in the development and treatment of rheumatic diseases particularly those which have an associated autoimmune element may be important for the long-term management of such conditions.
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56
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Johansson C, Tumber A, Che K, Cain P, Nowak R, Gileadi C, Oppermann U. The roles of Jumonji-type oxygenases in human disease. Epigenomics 2014; 6:89-120. [PMID: 24579949 PMCID: PMC4233403 DOI: 10.2217/epi.13.79] [Citation(s) in RCA: 126] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The iron- and 2-oxoglutarate-dependent oxygenases constitute a phylogenetically conserved class of enzymes that catalyze hydroxylation reactions in humans by acting on various types of substrates, including metabolic intermediates, amino acid residues in different proteins and various types of nucleic acids. The discovery of jumonji (Jmj), the founding member of a class of Jmj-type chromatin modifying enzymes and transcriptional regulators, has culminated in the discovery of several branches of histone lysine demethylases, with essential functions in regulating the epigenetic landscape of the chromatin environment. This work has now been considerably expanded into other aspects of epigenetic biology and includes the discovery of enzymatic steps required for methyl-cytosine demethylation as well as modification of RNA and ribosomal proteins. This overview aims to summarize the current knowledge on the human Jmj-type enzymes and their involvement in human pathological processes, including development, cancer, inflammation and metabolic diseases.
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Affiliation(s)
- Catrine Johansson
- Structural Genomics Consortium, University of Oxford, Old Road Campus, Roosevelt Drive, Headington, OX3 7DQ, UK
| | - Anthony Tumber
- Structural Genomics Consortium, University of Oxford, Old Road Campus, Roosevelt Drive, Headington, OX3 7DQ, UK
| | - KaHing Che
- Structural Genomics Consortium, University of Oxford, Old Road Campus, Roosevelt Drive, Headington, OX3 7DQ, UK
- Botnar Research Center, NIHR Oxford Biomedical Research Unit, Nuffield Department of Orthopaedics, Rheumatology & Musculoskeletal Sciences, Oxford, OX3 7LD, UK
| | - Peter Cain
- Botnar Research Center, NIHR Oxford Biomedical Research Unit, Nuffield Department of Orthopaedics, Rheumatology & Musculoskeletal Sciences, Oxford, OX3 7LD, UK
| | - Radoslaw Nowak
- Structural Genomics Consortium, University of Oxford, Old Road Campus, Roosevelt Drive, Headington, OX3 7DQ, UK
- Botnar Research Center, NIHR Oxford Biomedical Research Unit, Nuffield Department of Orthopaedics, Rheumatology & Musculoskeletal Sciences, Oxford, OX3 7LD, UK
- Systems Approaches to Biomedical Sciences, Industrial Doctorate Center (SABS IDC) Oxford, UK
| | - Carina Gileadi
- Structural Genomics Consortium, University of Oxford, Old Road Campus, Roosevelt Drive, Headington, OX3 7DQ, UK
| | - Udo Oppermann
- Structural Genomics Consortium, University of Oxford, Old Road Campus, Roosevelt Drive, Headington, OX3 7DQ, UK
- Botnar Research Center, NIHR Oxford Biomedical Research Unit, Nuffield Department of Orthopaedics, Rheumatology & Musculoskeletal Sciences, Oxford, OX3 7LD, UK
- Systems Approaches to Biomedical Sciences, Industrial Doctorate Center (SABS IDC) Oxford, UK
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Abstract
Epigenetic mechanisms are proposed to underlie aberrant gene expression in systemic lupus erythematosus (SLE) that results in dysregulation of the immune system and loss of tolerance. Modifications of DNA and histones require substrates derived from diet and intermediary metabolism. DNA and histone methyltransferases depend on S-adenosylmethionine (SAM) as a methyl donor. SAM is generated from adenosine triphosphate (ATP) and methionine by methionine adenosyltransferase (MAT), a redox-sensitive enzyme in the SAM cycle. The availability of B vitamins and methionine regulate SAM generation. The DNA of SLE patients is hypomethylated, indicating dysfunction in the SAM cycle and methyltransferase activity. Acetyl-CoA, which is necessary for histone acetylation, is generated from citrate produced in mitochondria. Mitochondria are also responsible for de novo synthesis of flavin adenine dinucleotide (FAD) for histone demethylation. Mitochondrial oxidative phosphorylation is the dominant source of ATP. The depletion of ATP in lupus T cells may affect MAT activity as well as adenosine monophosphate (AMP) activated protein kinase (AMPK), which phosphorylates histones and inhibits mechanistic target of rapamycin (mTOR). In turn, mTOR can modify epigenetic pathways including methylation, demethylation, and histone phosphorylation and mediates enhanced T-cell activation in SLE. Beyond their role in metabolism, mitochondria are the main source of reactive oxygen intermediates (ROI), which activate mTOR and regulate the activity of histone and DNA modifying enzymes. In this review we will focus on the sources of metabolites required for epigenetic regulation and how the flux of the underlying metabolic pathways affects gene expression.
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Affiliation(s)
- Zachary Oaks
- Division of Rheumatology, Departments of Medicine, Microbiology and Immunology, and Biochemistry and Molecular Biology, State University of New York, Upstate Medical University, College of Medicine , Syracuse, NY , USA
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Gray SG. Perspectives on epigenetic-based immune intervention for rheumatic diseases. Arthritis Res Ther 2013; 15:207. [PMID: 23510070 PMCID: PMC3672716 DOI: 10.1186/ar4167] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Rheumatic disease can loosely be described as any painful condition affecting the loco-motor system, including joints, muscles, connective tissues, and soft tissues around the joints and bones. There is a wide spectrum of rheumatic diseases, many of which involve autoimmunity, including systemic lupus erythematosus and rheumatoid arthritis. A significant body of evidence now links aberrant epigenetic regulation of gene expression with rheumatic disease and points toward the use of epigenetic targeting agents as potential new treatment options, particularly for those conditions associated with an autoimmune element. In this perspective, I will briefly cover the current knowledge surrounding this area in the field of rheumatology.
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Wang Z, Zheng Y, Hou C, Yang L, Li X, Lin J, Huang G, Lu Q, Wang CY, Zhou Z. DNA methylation impairs TLR9 induced Foxp3 expression by attenuating IRF-7 binding activity in fulminant type 1 diabetes. J Autoimmun 2013; 41:50-9. [PMID: 23490285 DOI: 10.1016/j.jaut.2013.01.009] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2013] [Accepted: 01/07/2013] [Indexed: 10/27/2022]
Abstract
Fulminant type 1 diabetes (FT1D) is an extremely aggressive disease characterized by the abrupt onset of insulin-deficient hyperglycemia. However, the precise mechanisms underlying disease etiology almost remain unclear. As mice deficient in regulatory T cells (Tregs) are prone to the development of an FT1D-like phenotype, we thus investigated whether FT1D patients manifest Treg deficiency and explored the related mechanisms. We first noted a significant reduction for Foxp3 and CTLA4 expression levels in PBMCs of FT1D patients. IRF-7 was found to selectively bind to the Foxp3 promoter, and by which it promotes Foxp3 transcription. Therefore, ectopic IRF-7 expression significantly promoted Foxp3 and CTLA4 expression in PBMCs, while knockdown of IRF-7 manifested opposite effect. Importantly, stimulation of PBMCs with CpG ODN, a ligand for TLR9, significantly induced Foxp3 expression, demonstrating that TLR9 signaling positively regulates Treg development. However, knockdown of IRF-7 expression almost completely diminished the enhancing effect of TLR9 signaling on Foxp3 expression, suggesting that IRF-7 is a downstream molecule of TLR9 signaling and is essential for TLR9 induced Treg generation. Of interestingly note, the Foxp3 promoter in FT1D patients was hypermethylated, indicating that DNA methylation could be a causative factor responsible for the reduced Foxp3 expression in FT1D patients. Indeed, our mechanistic studies revealed that DNA methylation blocked IRF-7 binding to the Foxp3 promoter. Together, our data support the notion that environmental insults in genetic predisposed subjects trigger Foxp3 promoter hypermethylation, which then prevents IRF-7 binding to the Foxp3 promoter and impairs Treg development/functionality contributing to the pathogenesis of FT1D.
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Affiliation(s)
- Zhen Wang
- Diabetes Center, 2nd Xiangya Hospital, and Institute of Metabolism and Endocrinology, Key Laboratory of Diabetes Immunology, Ministry of Education, Central South University, 139 Renmin Middle Rd, Changsha, Hunan 410011, China
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60
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The critical importance of epigenetics in autoimmunity. J Autoimmun 2013; 41:1-5. [PMID: 23375849 DOI: 10.1016/j.jaut.2013.01.010] [Citation(s) in RCA: 118] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2013] [Accepted: 01/13/2013] [Indexed: 11/21/2022]
Abstract
Autoimmune diseases are characterized by aberrant immune responses against healthy cells and tissues, in which a given individual's genetic susceptibilities play a central role; however, the exact mechanisms underlying the development of these conditions remain for the most part unknown. In recent years, accumulating evidence has demonstrated that, in addition to genetics, other complementary mechanisms are involved in the pathogenesis of autoimmunity, in particular, epigenetics. Epigenetics is defined as stable and heritable patterns of gene expression that do not entail any alterations to the original DNA sequence. Epigenetic mechanisms primarily consist of DNA methylation, histone modifications and small non-coding RNA transcripts. Epigenetic marks can be affected by age and other environmental triggers, providing a plausible link between environmental factors and the onset and development of various human diseases. Because of their primary function in regulating timely gene expression, epigenetic mechanisms offer potential advantages in terms of interpreting the molecular basis of complicated diseases and providing new promising therapeutic avenues for their treatment. The present review focuses on recent progress made in elucidating the relationship between epigenetics and the pathogenesis of autoimmune diseases, including systemic lupus erythematosus, rheumatoid arthritis, systemic sclerosis, primary Sjögren's syndrome, primary biliary cirrhosis, psoriasis and type 1 diabetes.
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Abstract
Systemic lupus erythematosus is a chronic relapsing autoimmune disease that primarily
afflicts women, and both a genetic predisposition and appropriate environmental
exposures are required for lupus to develop and flare. The genetic requirement is
evidenced by an increased concordance in identical twins and by the validation of at
least 35 single-nucleotide polymorphisms predisposing patients to lupus. Genes alone,
though, are not enough. The concordance of lupus in identical twins is often
incomplete, and when concordant, the age of onset is usually different. Lupus is also
not present at birth, but once the disease develops, it typically follows a chronic
relapsing course. Thus, genes alone are insufficient to cause human lupus, and
additional factors encountered in the environment and over time are required to
initiate the disease and subsequent flares. The nature of the environmental
contribution, though, and the mechanisms by which environmental agents modify the
immune response to cause lupus onset and flares in genetically predisposed people
have been controversial. Reports that the lupus-inducing drugs procainamide and
hydralazine are epigenetic modifiers, that epigenetically modified T cells are
sufficient to cause lupus-like autoimmunity in animal models, and that patients with
active lupus have epigenetic changes similar to those caused by procainamide and
hydralazine have prompted a growing interest in how epigenetic alterations contribute
to this disease. Understanding how epigenetic mechanisms modify T cells to contribute
to lupus requires an understanding of how epigenetic mechanisms regulate gene
expression. The roles of DNA methylation, histone modifications, and microRNAs in
lupus pathogenesis will be reviewed here.
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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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Aberrant histone modifications in peripheral blood mononuclear cells from patients with Henoch-Schönlein purpura. Clin Immunol 2013; 146:165-75. [PMID: 23353785 DOI: 10.1016/j.clim.2012.12.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2012] [Revised: 12/17/2012] [Accepted: 12/19/2012] [Indexed: 02/07/2023]
Abstract
Henoch-Schönlein purpura (HSP), the most common type of leukocytoclastic vasculitis, is caused by T cell-mediated autoimmune reactions. In this study, we analyze histone modification patterns in peripheral blood mononuclear cells (PBMCs) of HSP patients, and investigate the expression levels of inflammatory cytokines (IFN-γ, IL-2, IL-4, IL-6 and IL-13), transcription factors (T-bet, GATA-3 and TIM-1) and chemokines (CXCL4 and CXCL10) in HSP patients. Our results show that histone H3 acetylation and methylation are significantly enhanced in PBMCs from HSP patients. We also demonstrate specifically that marked increases in histone H3 acetylation and H3 lysine 4 trimethylation occur at the IL-4 loci in these patients. In addition, the expression levels of IL-4, IL-6, IL-13, GATA-3, TIM-1 and CXCL4 are also increased. These findings suggest that abnormal histone modifications are present in the PBMCs of patients with HSP, possibly contributing to the activation of pathological immune responses associated with HSP.
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Ding S, Liang Y, Zhao M, Liang G, Long H, Zhao S, Wang Y, Yin H, Zhang P, Zhang Q, Lu Q. Decreased microRNA-142-3p/5p expression causes CD4+ T cell activation and B cell hyperstimulation in systemic lupus erythematosus. ACTA ACUST UNITED AC 2012; 64:2953-63. [PMID: 22549634 DOI: 10.1002/art.34505] [Citation(s) in RCA: 153] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
OBJECTIVE To examine the role of microRNA-142-3p/5p (miR-142-3p/5p) in the development of autoimmunity in patients with systemic lupus erythematosus (SLE). METHODS MicroRNA-142-3p/5p expression levels were determined by real-time quantitative polymerase chain reaction, and potential target genes were verified using luciferase reporter gene assays. The effects of miR-142-3p/5p on T cell function were assessed by transfection with miR-142-3p/5p inhibitors or mimics. Histone modifications and methylation levels within a putative regulatory region of the miR-142 locus were detected by chromatin immunoprecipitation assay and bisulfite sequencing, respectively. RESULTS We confirmed that miR-142-3p and miR-142-5p were significantly down-regulated in SLE CD4+ T cells compared with healthy controls and observed that miR-142-3p/5p levels were inversely correlated with the putative SLE-related targets signaling lymphocytic activation molecule-associated protein (SAP), CD84, and interleukin-10 (IL-10). We demonstrated that miR-142-3p and miR-142-5p directly inhibit SAP, CD84, and IL-10 translation, and that reduced miR-142-3p/5p expression in CD4+ T cells can significantly increase protein levels of these target genes. Furthermore, inhibiting miR-142-3p/5p in healthy donor CD4+ T cells caused T cell overactivation and B cell hyperstimulation, whereas overexpression of miR-142-3p/5p in SLE CD4+ T cells had the opposite effect. We also observed that the decrease in miR-142 expression in SLE CD4+ T cells correlated with changes to histone modifications and DNA methylation levels upstream of the miR-142 precursor sequence. CONCLUSION The results of this study indicate that reduced expression of miR-142-3p/5p in the CD4+ T cells of patients with SLE causes T cell activity and B cell hyperstimulation.
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Affiliation(s)
- Shu Ding
- Second Xiangya Hospital and Central South University, Changsha, Hunan, China
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65
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Ngalamika O, Zhang Y, Yin H, Zhao M, Gershwin ME, Lu Q. Epigenetics, autoimmunity and hematologic malignancies: a comprehensive review. J Autoimmun 2012; 39:451-65. [PMID: 23084980 DOI: 10.1016/j.jaut.2012.09.002] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2012] [Accepted: 09/24/2012] [Indexed: 12/17/2022]
Abstract
The relationships between immunological dysfunction, loss of tolerance and hematologic malignancies have been a focus of attention in attempts to understand the appearance of a higher degree of autoimmune disease and lymphoma in children with congenital immunodeficiency. Although multiple hypotheses have been offered, it is clear that stochastic processes play an important role in the immunopathology of these issues. In particular, accumulating evidence is defining a role of epigenetic mechanisms as being critical in this continuous spectrum between autoimmunity and lymphoma. In this review, we focus attention predominantly on the relationships between T helper 17 (Th17) and T regulatory populations that alter local microenvironments and ultimately the expression or transcription factors involved in cell activation and differentiation. Abnormal expression in any of the molecules involved in Th17 and/or Treg development alter immune homeostasis and in genetically susceptible hosts may lead to the appearance of autoimmunity and/or lymphoma. These observations have clinical significance in explaining the discordance of autoimmunity in identical twins. They are also particularly important in the relationships between primary immune deficiency syndromes, immune dysregulation and an increased risk of lymphoma. Indeed, defining the factors that determine epigenetic alterations and their relationships to immune homeostasis will be a challenge greater or even equal to the human genome project.
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Affiliation(s)
- Owen Ngalamika
- Department of Dermatology, Second Xiangya Hospital, Central South University, Hunan Key Laboratory of Medical Epigenetics, #139 Renmin Middle Rd, Changsha, Hunan 410011, PR China
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Epigenetic control and cancer: the potential of histone demethylases as therapeutic targets. Pharmaceuticals (Basel) 2012; 5:963-90. [PMID: 24280700 PMCID: PMC3816642 DOI: 10.3390/ph5090963] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2012] [Revised: 07/21/2012] [Accepted: 08/17/2012] [Indexed: 01/01/2023] Open
Abstract
The development of cancer involves an immense number of factors at the molecular level. These factors are associated principally with alterations in the epigenetic mechanisms that regulate gene expression profiles. Studying the effects of chromatin structure alterations, which are caused by the addition/removal of functional groups to specific histone residues, are of great interest as a promising way to identify markers for cancer diagnosis, classify the disease and determine its prognosis, and these markers could be potential targets for the treatment of this disease in its different forms. This manuscript presents the current point of view regarding members of the recently described family of proteins that exhibit histone demethylase activity; histone demethylases are genetic regulators that play a fundamental role in both the activation and repression of genes and whose expression has been observed to increase in many types of cancer. Some fundamental aspects of their association with the development of cancer and their relevance as potential targets for the development of new therapeutic strategies at the epigenetic level are discussed in the following manuscript.
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67
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Borchers AT, Leibushor N, Naguwa SM, Cheema GS, Shoenfeld Y, Gershwin ME. Lupus nephritis: a critical review. Autoimmun Rev 2012; 12:174-94. [PMID: 22982174 DOI: 10.1016/j.autrev.2012.08.018] [Citation(s) in RCA: 160] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/12/2012] [Indexed: 01/18/2023]
Abstract
Lupus nephritis remains one of the most severe manifestations of systemic lupus erythematosus associated with considerable morbidity and mortality. A better understanding of the pathogenesis of lupus nephritis is an important step in identifying more targeted and less toxic therapeutic approaches. Substantial research has helped define the pathogenetic mechanisms of renal manifestations and, in particular, the complex role of type I interferons is increasingly recognized; new insights have been gained into the contribution of immune complexes containing endogenous RNA and DNA in triggering the production of type I interferons by dendritic cells via activation of endosomal toll-like receptors. At the same time, there have been considerable advances in the treatment of lupus nephritis. Corticosteroids have long been the cornerstone of therapy, and the addition of cyclophosphamide has contributed to renal function preservation in patients with severe proliferative glomerulonephritis, though at the cost of serious adverse events. More recently, in an effort to minimize drug toxicity and achieve equal effectiveness, other immunosuppressive agents, including mycophenolate mofetil, have been introduced. Herein, we provide a detailed review of the trials that established the equivalency of these agents in the induction and/or maintenance therapy of lupus nephritis, culminating in the recent publication of new treatment guidelines by the American College of Rheumatology. Although newer biologics have been approved and continue to be a focus of research, they have, for the most part, been relatively disappointing compared to the effectiveness of biologics in other autoimmune diseases. Early diagnosis and treatment are essential for renal preservation.
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Affiliation(s)
- Andrea T Borchers
- Division of Rheumatology, Allergy and Clinical Immunology, University of California at Davis School of Medicine, Davis, CA 95616, United States
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68
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Current world literature. Curr Opin Rheumatol 2012; 24:586-94. [PMID: 22871955 DOI: 10.1097/bor.0b013e32835793df] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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69
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Wang X, Li JP, Kuo HK, Chiu LL, Dement GA, Lan JL, Chen DY, Yang CY, Hu H, Tan TH. Down-regulation of B cell receptor signaling by hematopoietic progenitor kinase 1 (HPK1)-mediated phosphorylation and ubiquitination of activated B cell linker protein (BLNK). J Biol Chem 2012; 287:11037-48. [PMID: 22334673 DOI: 10.1074/jbc.m111.310946] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Hematopoietic progenitor kinase 1 (HPK1) is a Ste20-like serine/threonine kinase that suppresses immune responses and autoimmunity. B cell receptor (BCR) signaling activates HPK1 by inducing BLNK/HPK1 interaction. Whether HPK1 can reciprocally regulate BLNK during BCR signaling is unknown. Here, we show that HPK1-deficient B cells display hyper-proliferation and hyper-activation of IκB kinase and MAPKs (ERK, p38, and JNK) upon the ligation of BCR. HPK1 attenuates BCR-induced cell activation via inducing BLNK threonine 152 phosphorylation, which mediates BLNK/14-3-3 binding. Furthermore, threonine 152-phosphorylated BLNK is ubiquitinated at lysine residues 37, 38, and 42, leading to attenuation of MAPK and IκB kinase activation in B cells during BCR signaling. These results reveal a novel negative feedback regulation of BCR signaling by HPK1-mediated phosphorylation, ubiquitination, and subsequent degradation of the activated BLNK.
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Affiliation(s)
- Xiaohong Wang
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, Texas 77030, USA
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