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Abstract
INTRODUCTION Epigenetics describes the phenomenon of heritable changes in gene regulation governed by non-Mendelian processes, primarily through biochemical modifications to chromatin that occur during cell differentiation and development. Abnormal levels of DNA and/or histone modifications are observed in patients with a wide variety of chronic diseases. Drugs that target the proteins controlling these chromatin modifications can modulate the expression of clusters of genes, potentially offering higher therapeutic efficacy than classical agents with single target pharmacologies that are susceptible to biochemical pathway degeneracy. AREAS COVERED This article reviews research characterizing dysregulation of epigenetic processes in cancer, immuno-inflammatory, psychiatric, neurological, metabolic and virology disease areas, and summarizes recent developments in identifying small molecule modulators that are being used to inform target discovery and initiate drug discovery projects. EXPERT OPINION There are numerous potential opportunities for epigenetic modulators in treating a wide range of chronic diseases; however, the field is complex, involving > 300 proteins, and much work is still required to provide tools to unravel the functions of individual proteins, particularly in vivo. This groundwork is essential to allow the drug discovery community to focus on those epigenetic proteins most likely to be suitable targets for safe, efficacious new therapies.
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Affiliation(s)
- Tom D Heightman
- Astex Therapeutics Ltd., 436 Cambridge Science Park, Cambridge CB4 0QA, UK.
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102
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Abstract
Epigenetic modifications occur in response to environmental changes and play a fundamental role in gene expression following environmental stimuli. Major epigenetic events include methylation and acetylation of histones and regulatory factors, DNA methylation, and small non-coding RNAs. Diet, pollution, infections, and other environmental factors have profound effects on epigenetic modifications and trigger susceptibility to diseases. Despite a growing body of literature addressing the role of the environment on gene expression, very little is known about the epigenetic pathways involved in the modulation of inflammatory and anti-inflammatory genes. This review summarizes the current knowledge about epigenetic control mechanisms during the inflammatory response.
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Affiliation(s)
- D Bayarsaihan
- Center for Regenerative Medicine and Skeletal Development, Department of Reconstructive Sciences, School of Dentistry, University of Connecticut Health Center, 262 Farmington Avenue, Farmington, CT 06030, USA.
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103
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Abstract
Epigenetics is one of the most rapidly expanding fields in biology. The recent characterization of a human DNA methylome at single nucleotide resolution, the discovery of the CpG island shores, the finding of new histone variants and modifications, and the unveiling of genome-wide nucleosome positioning maps highlight the accelerating speed of discovery over the past two years. Increasing interest in epigenetics has been accompanied by technological breakthroughs that now make it possible to undertake large-scale epigenomic studies. These allow the mapping of epigenetic marks, such as DNA methylation, histone modifications and nucleosome positioning, which are critical for regulating gene and noncoding RNA expression. In turn, we are learning how aberrant placement of these epigenetic marks and mutations in the epigenetic machinery is involved in disease. Thus, a comprehensive understanding of epigenetic mechanisms, their interactions and alterations in health and disease, has become a priority in biomedical research.
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Affiliation(s)
- Anna Portela
- Cancer Epigenetics and Biology Program, Bellvitge Biomedical Research Institute, Barcelona, Catalonia, Spain
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104
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Karouzakis E, Gay RE, Gay S, Neidhart M. Epigenetic deregulation in rheumatoid arthritis. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2011; 711:137-49. [PMID: 21627047 DOI: 10.1007/978-1-4419-8216-2_10] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
In this chapter, we discuss the current understanding of the possible epigenetics changes that occur in rheumatoid arthritis. In particular, we describe that deregulation ofDNA methylation and histone modifications can occur in the immune system and lead to rheumatoid arthritis. In addition, we discuss the role of rheumatoid arthritis synovial fibroblasts in autoimmunity. Examples of changes in DNA methylation and histone modification occurring in synovial fibroblasts during the disease process are reviewed in this chapter. In conclusion, we discuss the possible use of epigenetic therapy and describe future experiments that can elucidate further the epigenetic changes observed in the disease.
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Affiliation(s)
- Emmanuel Karouzakis
- Center for Experimental Rheumatology, University Hospital Zurich, Gloriastrasse, Zurich, Switzerland
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105
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Csepeggi C, Jiang M, Kojima F, Crofford LJ, Frolov A. Somatic cell plasticity and Niemann-Pick type C2 protein: fibroblast activation. J Biol Chem 2010; 286:2078-87. [PMID: 21084287 DOI: 10.1074/jbc.m110.135897] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
A growing body of evidence points toward activated fibroblasts, also known as myofibroblasts, as one of the leading mediators in several major human pathologies including proliferative fibrotic disorders, invasive tumor growth, rheumatoid arthritis, and atherosclerosis. Niemann-Pick Type C2 (NPC2) protein has been recently identified as a product of the second gene in NPC disease. It encodes ubiquitous, highly conserved, secretory protein with the poorly defined function. Here we show that NPC2 deficiency in human fibroblasts confers their activation. The activation phenomenon was not limited to fibroblasts as it was also observed in aortic smooth muscle cells upon silencing NPC2 gene by siRNA. More importantly, activated synovial fibroblasts isolated from patients with rheumatoid arthritis were also identified as NPC2-deficient at both the NPC2 mRNA and protein levels. The molecular mechanism responsible for activation of NPC2-null cells was shown to be a sustained phosphorylation of ERK 1/2 mitogen-activated protein kinase (MAPK), which fulfills both the sufficient and necessary fibroblast activation criteria. All of these findings highlight a novel mechanism where NPC2 by negatively regulating ERK 1/2 MAPK phosphorylation may efficiently suppress development of maladaptive tissue remodeling and inflammation.
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Affiliation(s)
- Chad Csepeggi
- Division of Cardiovascular Diseases, Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, Ohio 45267, USA
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106
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Szarc vel Szic K, Ndlovu MN, Haegeman G, Vanden Berghe W. Nature or nurture: let food be your epigenetic medicine in chronic inflammatory disorders. Biochem Pharmacol 2010; 80:1816-32. [PMID: 20688047 DOI: 10.1016/j.bcp.2010.07.029] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2010] [Revised: 07/19/2010] [Accepted: 07/23/2010] [Indexed: 01/05/2023]
Abstract
Numerous clinical, physiopathological and epidemiological studies have underlined the detrimental or beneficial role of nutritional factors in complex inflammation related disorders such as allergy, asthma, obesity, type 2 diabetes, cardiovascular disease, rheumatoid arthritis and cancer. Today, nutritional research has shifted from alleviating nutrient deficiencies to chronic disease prevention. It is known that lifestyle, environmental conditions and nutritional compounds influence gene expression. Gene expression states are set by transcriptional activators and repressors and are often locked in by cell-heritable chromatin states. Only recently, it has been observed that the environmental conditions and daily diet can affect transgenerational gene expression via "reversible" heritable epigenetic mechanisms. Epigenetic changes in DNA methylation patterns at CpG sites (epimutations) or corrupt chromatin states of key inflammatory genes and noncoding RNAs, recently emerged as major governing factors in cancer, chronic inflammatory and metabolic disorders. Reciprocally, inflammation, metabolic stress and diet composition can also change activities of the epigenetic machinery and indirectly or directly change chromatin marks. This has recently launched re-exploration of anti-inflammatory bioactive food components for characterization of their effects on epigenome modifying enzymatic activities (acetylation, methylation, phosphorylation, ribosylation, oxidation, ubiquitination, sumoylation). This may allow to improve healthy aging by reversing disease prone epimutations involved in chronic inflammatory and metabolic disorders.
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Affiliation(s)
- Katarzyna Szarc vel Szic
- Laboratory of Eukaryotic Gene Expression and Signal Transduction (LEGEST), Department of Physiology, Ghent University, K.L. Ledeganckstraat 35, Gent, Belgium
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107
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Frommer KW, Zimmermann B, Meier FMP, Schröder D, Heil M, Schäffler A, Büchler C, Steinmeyer J, Brentano F, Gay S, Müller-Ladner U, Neumann E. Adiponectin-mediated changes in effector cells involved in the pathophysiology of rheumatoid arthritis. ACTA ACUST UNITED AC 2010; 62:2886-99. [DOI: 10.1002/art.27616] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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108
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Toussirot É, Khan KA, Herbein G. Histone deacetylase inhibitors: a new and promising drug class for the treatment of arthritis? Clin Epigenetics 2010; 1:3-6. [PMID: 22704084 PMCID: PMC3365362 DOI: 10.1007/s13148-010-0002-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2010] [Accepted: 05/03/2010] [Indexed: 01/16/2023] Open
Affiliation(s)
- Éric Toussirot
- Department of Rheumatology, University Hospital Jean Minjoz, 25000 Besançon, France
- UPRES EA 4266 Pathogens and Inflammation, University of Franche-Comté, 25000 Besançon, France
- CIC-Biotherapy 506, University Hospital St Jacques, 25000 Besançon, France
| | - Kashif Aziz Khan
- Department of Virology, University Hospital St Jacques, 25000 Besançon, France
- UPRES EA 4266 Pathogens and Inflammation, University of Franche-Comté, 25000 Besançon, France
| | - Georges Herbein
- Department of Virology, University Hospital St Jacques, 25000 Besançon, France
- UPRES EA 4266 Pathogens and Inflammation, University of Franche-Comté, 25000 Besançon, France
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109
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Sabeh F, Fox D, Weiss SJ. Membrane-type I matrix metalloproteinase-dependent regulation of rheumatoid arthritis synoviocyte function. THE JOURNAL OF IMMUNOLOGY 2010; 184:6396-406. [PMID: 20483788 DOI: 10.4049/jimmunol.0904068] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
In rheumatoid arthritis, the coordinated expansion of the synoviocyte mass is coupled with a pathologic angiogenic response that leads to the destructive remodeling of articular as well as surrounding connective tissues. Although rheumatoid synoviocytes express a multiplicity of proteolytic enzymes, the primary effectors of cartilage, ligament, and tendon damage remain undefined. Herein, we demonstrate that human rheumatoid synoviocytes mobilize the membrane-anchored matrix metalloproteinase (MMP), membrane-type I MMP (MT1-MMP), to dissolve and invade type I and type II collagen-rich tissues. Though rheumatoid synoviocytes also express a series of secreted collagenases, these proteinases are ineffective in mediating collagenolytic activity in the presence of physiologic concentrations of plasma- or synovial fluid-derived antiproteinases. Furthermore, MT1-MMP not only directs the tissue-destructive properties of rheumatoid synoviocytes but also controls synoviocyte-initiated angiogenic responses in vivo. Together, these findings identify MT1-MMP as a master regulator of the pathologic extracellular matrix remodeling that characterizes rheumatoid arthritis as well as the coupled angiogenic response that maintains the aggressive phenotype of the advancing pannus.
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Affiliation(s)
- Farideh Sabeh
- Division of Molecular Medicine and Genetics, Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA
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111
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The discovery of novel experimental therapies for inflammatory arthritis. Mediators Inflamm 2010; 2009:698769. [PMID: 20339519 PMCID: PMC2842969 DOI: 10.1155/2009/698769] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2009] [Accepted: 12/21/2009] [Indexed: 12/16/2022] Open
Abstract
Conventional and biologic disease-modifying antirheumatic drugs have revolutionized the medical therapy of inflammatory arthritis. However, it remains unclear as to what can be done to treat immune-mediated chronic inflammation after patients become refractory to these therapies or develop serious side-effects and/or infections forcing drug withdrawal. Because of these concerns it is imperative that novel targets be continuously identified and experimental strategies designed to test potential arthritis interventions in vitro, but more importantly, in well-validated animal models of inflammatory arthritis. Over the past few years, sphingosine-1-phosphate, interleukin-7 receptor, spleen tyrosine kinase, extracellular signal-regulated kinase, mitogen-activated protein kinase 5/p38 kinase regulated/activated protein kinase, micro-RNAs, tumor necrosis factor-related apoptosis inducing ligand and the polyubiquitin-proteasome pathway were identified as promising novel targets for potential antiarthritis drug development. Indeed several experimental compounds alter the biological activity of these targets and have shown clinical efficacy in animal models of arthritis. A few of them have even entered the first phase of human clinical trials.
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