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1.
Genes (Basel) ; 11(1)2020 01 18.
Artigo em Inglês | MEDLINE | ID: mdl-31963661

RESUMO

Immune cells are one of the most complex and diverse systems in the human organism. Such diversity implies an intricate network of different cell types and interactions that are dependently interconnected. The processes by which different cell types differentiate from progenitors, mature, and finally exert their function requires an orchestrated succession of molecular processes that determine cell phenotype and function. The acquisition of these phenotypes is highly dependent on the establishment of unique epigenetic profiles that confer identity and function on the various types of effector cells. These epigenetic mechanisms integrate microenvironmental cues into the genome to establish specific transcriptional programs. Epigenetic modifications bridge environment and genome regulation and play a role in human diseases by their ability to modulate physiological programs through external stimuli. DNA methylation is one of the most ubiquitous, stable, and widely studied epigenetic modifications. Recent technological advances have facilitated the generation of a vast amount of genome-wide DNA methylation data, providing profound insights into the roles of DNA methylation in health and disease. This review considers the relevance of DNA methylation to immune system cellular development and function, as well as the participation of DNA methylation defects in immune-mediated pathologies, illustrated by selected paradigmatic diseases.

2.
Nucleic Acids Res ; 48(2): 665-681, 2020 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-31799621

RESUMO

Sirtuins 1 and 2 (SIRT1/2) are two NAD-dependent deacetylases with major roles in inflammation. In addition to deacetylating histones and other proteins, SIRT1/2-mediated regulation is coupled with other epigenetic enzymes. Here, we investigate the links between SIRT1/2 activity and DNA methylation in macrophage differentiation due to their relevance in myeloid cells. SIRT1/2 display drastic upregulation during macrophage differentiation and their inhibition impacts the expression of many inflammation-related genes. In this context, SIRT1/2 inhibition abrogates DNA methylation gains, but does not affect demethylation. Inhibition of hypermethylation occurs at many inflammatory loci, which results in more drastic upregulation of their expression upon macrophage polarization following bacterial lipopolysaccharide (LPS) challenge. SIRT1/2-mediated gains of methylation concur with decreases in activating histone marks, and their inhibition revert these histone marks to resemble an open chromatin. Remarkably, specific inhibition of DNA methyltransferases is sufficient to upregulate inflammatory genes that are maintained in a silent state by SIRT1/2. Both SIRT1 and SIRT2 directly interact with DNMT3B, and their binding to proinflammatory genes is lost upon exposure to LPS or through pharmacological inhibition of their activity. In all, we describe a novel role for SIRT1/2 to restrict premature activation of proinflammatory genes.

3.
Sci Data ; 6(1): 256, 2019 10 31.
Artigo em Inglês | MEDLINE | ID: mdl-31672995

RESUMO

Multi-omics approaches use a diversity of high-throughput technologies to profile the different molecular layers of living cells. Ideally, the integration of this information should result in comprehensive systems models of cellular physiology and regulation. However, most multi-omics projects still include a limited number of molecular assays and there have been very few multi-omic studies that evaluate dynamic processes such as cellular growth, development and adaptation. Hence, we lack formal analysis methods and comprehensive multi-omics datasets that can be leveraged to develop true multi-layered models for dynamic cellular systems. Here we present the STATegra multi-omics dataset that combines measurements from up to 10 different omics technologies applied to the same biological system, namely the well-studied mouse pre-B-cell differentiation. STATegra includes high-throughput measurements of chromatin structure, gene expression, proteomics and metabolomics, and it is complemented with single-cell data. To our knowledge, the STATegra collection is the most diverse multi-omics dataset describing a dynamic biological system.

4.
Genome Med ; 11(1): 66, 2019 10 29.
Artigo em Inglês | MEDLINE | ID: mdl-31665078

RESUMO

BACKGROUND: Sepsis, a life-threatening organ dysfunction caused by a dysregulated systemic immune response to infection, associates with reduced responsiveness to subsequent infections. How such tolerance is acquired is not well understood but is known to involve epigenetic and transcriptional dysregulation. METHODS: Bead arrays were used to compare global DNA methylation changes in patients with sepsis, non-infectious systemic inflammatory response syndrome, and healthy controls. Bioinformatic analyses were performed to dissect functional reprogramming and signaling pathways related to the acquisition of these specific DNA methylation alterations. Finally, in vitro experiments using human monocytes were performed to test the induction of similar DNA methylation reprogramming. RESULTS: Here, we focused on DNA methylation changes associated with sepsis, given their potential role in stabilizing altered phenotypes. Tolerized monocytes from patients with sepsis display changes in their DNA methylomes with respect to those from healthy controls, affecting critical monocyte-related genes. DNA methylation profiles correlate with IL-10 and IL-6 levels, significantly increased in monocytes in sepsis, as well as with the Sequential Organ Failure Assessment score; the observed changes associate with TFs and pathways downstream to toll-like receptors and inflammatory cytokines. In fact, in vitro stimulation of toll-like receptors in monocytes results in similar gains and losses of methylation together with the acquisition of tolerance. CONCLUSION: We have identified a DNA methylation signature associated with sepsis that is downstream to the response of monocytes to inflammatory signals associated with the acquisition of a tolerized phenotype and organic dysfunction.

5.
Trends Pharmacol Sci ; 40(11): 853-865, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31662207

RESUMO

In the past decade, we have witnessed considerable developments in understanding the roles and functions of miRNAs. In parallel, the identification of alterations in miRNA expression in inflammatory disease indicates their potential as therapeutic targets. Pharmacological treatments targeting abnormally expressed miRNAs for inflammatory diseases are not yet in clinical practice; however, some small compounds and nucleic acids targeting miRNAs have shown promise in preclinical development. Here, we focus on recent advances in understanding miRNA deregulation in inflammatory diseases and provide an overview of the current development of miRNA-based therapeutics in these diseases with an emphasis on newly discovered miRNA therapeutic targets.

6.
Ann Rheum Dis ; 78(11): 1505-1516, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31371305

RESUMO

OBJECTIVE: Rheumatoid arthritis (RA) is a chronic systemic autoimmune disease that mainly targets joints. Monocytes and macrophages are critical in RA pathogenesis and contribute to inflammatory lesions. These extremely plastic cells respond to extracellular signals which cause epigenomic changes that define their pathogenic phenotype. Here, we interrogated how DNA methylation alterations in RA monocytes are determined by extracellular signals. METHODS: High-throughput DNA methylation analyses of patients with RA and controls and in vitro cytokine stimulation were used to investigate the underlying mechanisms behind DNA methylation alterations in RA as well as their relationship with clinical parameters, including RA disease activity. RESULTS: The DNA methylomes of peripheral blood monocytes displayed significant changes and increased variability in patients with RA with respect to healthy controls. Changes in the monocyte methylome correlate with DAS28, in which high-activity patients are divergent from healthy controls in contrast to remission patients whose methylome is virtually identical to healthy controls. Indeed, the notion of a changing monocyte methylome is supported after comparing the profiles of same individuals at different stages of activity. We show how these changes are mediated by an increase in disease activity-associated cytokines, such as tumour necrosis factor alpha and interferons, as they recapitulate the DNA methylation changes observed in patients in vitro. CONCLUSION: We demonstrate a direct link between RA disease activity and the monocyte methylome through the action of inflammation-associated cytokines. Finally, we have obtained a DNA methylation-based mathematical formula that predicts inflammation-mediated disease activity for RA and other chronic immune-mediated inflammatory diseases.

7.
Front Immunol ; 10: 1880, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31440254

RESUMO

Mixed Connective Tissue Disease (MCTD) is a rare complex systemic autoimmune disease (SAD) characterized by the presence of increased levels of anti-U1 ribonucleoprotein autoantibodies and signs and symptoms that resemble other SADs such as systemic sclerosis (SSc), rheumatoid arthritis (RA), and systemic lupus erythematosus (SLE). Due to its low prevalence, this disease has been very poorly studied at the molecular level. We performed for the first time an epigenome-wide association study interrogating DNA methylation data obtained with the Infinium MethylationEPIC array from whole blood samples in 31 patients diagnosed with MCTD and 255 healthy subjects. We observed a pervasive hypomethylation involving 170 genes enriched for immune-related function such as those involved in type I interferon signaling pathways or in negative regulation of viral genome replication. We mostly identified epigenetic signals at genes previously implicated in other SADs, for example MX1, PARP9, DDX60, or IFI44L, for which we also observed that MCTD patients exhibit higher DNA methylation variability compared with controls, suggesting that these sites might be involved in plastic immune responses that are relevant to the disease. Through methylation quantitative trait locus (meQTL) analysis we identified widespread local genetic effects influencing DNA methylation variability at MCTD-associated sites. Interestingly, for IRF7, IFI44 genes, and the HLA region we have evidence that they could be exerting a genetic risk on MCTD mediated through DNA methylation changes. Comparison of MCTD-associated epigenome with patients diagnosed with SLE, or Sjögren's Syndrome, reveals a common interferon-related epigenetic signature, however we find substantial epigenetic differences when compared with patients diagnosed with rheumatoid arthritis and systemic sclerosis. Furthermore, we show that MCTD-associated CpGs are potential epigenetic biomarkers with high diagnostic value. Our study serves to reveal new genes and pathways involved in MCTD, to illustrate the important role of epigenetic modifications in MCTD pathology, in mediating the interaction between different genetic and environmental MCTD risk factors, and as potential biomarkers of SADs.

8.
Front Immunol ; 10: 878, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31105700

RESUMO

Common Variable Immunodeficiency (CVID) is characterized by impaired antibody production and poor terminal differentiation of the B cell compartment, yet its pathogenesis is still poorly understood. We first reported the occurrence of epigenetic alterations in CVID by high-throughput methylation analysis in CVID-discordant monozygotic twins. Data from a recent whole DNA methylome analysis throughout different stages of normal B cell differentiation allowed us to design a new experimental approach. We selected CpG sites for analysis based on two criteria: one, CpGs with potential association with the transcriptional status of relevant genes for B cell activation and differentiation; and two, CpGs that undergo significant demethylation from naïve to memory B cells in healthy individuals. DNA methylation was analyzed by bisulfite pyrosequencing of specific CpG sites in sorted naïve and memory B cell subsets from CVID patients and healthy donors. We observed impaired demethylation in two thirds of the selected CpGs in CVID memory B cells, in genes that govern B cell-specific processes or participate in B cell signaling. The degree of demethylation impairment associated with the extent of the memory B cell reduction. The impaired demethylation in such functionally relevant genes as AICDA in switched memory B cells correlated with a lower proliferative rate. Our new results reinforce the hypothesis of altered demethylation during B cell differentiation as a contributing pathogenic mechanism to the impairment of B cell function and maturation in CVID. In particular, deregulated epigenetic control of AICDA could play a role in the defective establishment of a post-germinal center B cell compartment in CVID.

9.
Clin Immunol ; 196: 64-71, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-29501540

RESUMO

Compelling evidences highlight the critical role of the tumor microenvironment as mediator of tumor progression and immunosuppression in several types of cancer. The reciprocal interplay between neoplastic and non-tumoral host cells is mediated by direct cell-to-cell contact, soluble factors and exosomes that result in differential gene expression patterns that are driven by epigenetic mechanisms. In this regard, extensive literature has described the abnormalities in the DNA methylation status and histone modification profiles in tumor cells. However, little is known about the mechanisms of epigenetic dysregulation that participate as a consequence of the intricate crosstalk among the cells within the tumor niche. This review summarizes the current knowledge on epigenetic changes that result from the interactions between myeloid, stromal and cancer cells in the tumor microenvironment and its functional impact in both tumorigenesis and tumor progression. We also discuss potential niche-specific epigenetic biomarkers to improve the prognosis and clinical treatment of cancer patients.


Assuntos
Epigênese Genética , Células Mieloides/metabolismo , Neoplasias/genética , Células Estromais/metabolismo , Evasão Tumoral/genética , Microambiente Tumoral/genética , Progressão da Doença , Expressão Gênica , Humanos , Células Mieloides/imunologia , Neoplasias/imunologia , Células Estromais/imunologia , Evasão Tumoral/imunologia , Microambiente Tumoral/imunologia
10.
Cell Rep ; 21(1): 154-167, 2017 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-28978469

RESUMO

Myeloid-derived suppressor cells (MDSCs) and dendritic cells (DCs) arise from common progenitors. Tumor-derived factors redirect differentiation from immune-promoting DCs to tolerogenic MDSCs, an immunological hallmark of cancer. Indeed, in vitro differentiation of DCs from human primary monocytes results in the generation of MDSCs under tumor-associated conditions (PGE2 or tumor cell-conditioned media). Comparison of MDSC and DC DNA methylomes now reveals extensive demethylation with specific gains of DNA methylation and repression of immunogenic-associated genes occurring in MDSCs specifically, concomitant with increased DNA methyltransferase 3A (DNMT3A) levels. DNMT3A downregulation erases MDSC-specific hypermethylation, and it abolishes their immunosuppressive capacity. Primary MDSCs isolated from ovarian cancer patients display a similar hypermethylation signature in connection with PGE2-dependent DNMT3A overexpression. Our study links PGE2- and DNMT3A-dependent hypermethylation with immunosuppressive MDSC functions, providing a promising target for therapeutic intervention.


Assuntos
DNA (Citosina-5-)-Metiltransferases/genética , Dinoprostona/farmacologia , Regulação Neoplásica da Expressão Gênica , Tolerância Imunológica , Células Supressoras Mieloides/efeitos dos fármacos , Neoplasias Ovarianas/genética , Antígeno CD11b/genética , Antígeno CD11b/imunologia , Diferenciação Celular/efeitos dos fármacos , Linhagem da Célula/efeitos dos fármacos , Linhagem da Célula/imunologia , Quimiocina CCL22/genética , Quimiocina CCL22/imunologia , Subunidade alfa 2 de Fator de Ligação ao Core/genética , Subunidade alfa 2 de Fator de Ligação ao Core/imunologia , Meios de Cultivo Condicionados/farmacologia , Modulador de Elemento de Resposta do AMP Cíclico/genética , Modulador de Elemento de Resposta do AMP Cíclico/imunologia , DNA (Citosina-5-)-Metiltransferases/imunologia , Metilação de DNA , Feminino , Humanos , Monócitos/efeitos dos fármacos , Monócitos/imunologia , Família Multigênica , Células Supressoras Mieloides/imunologia , Neoplasias Ovarianas/imunologia , Neoplasias Ovarianas/patologia , Cultura Primária de Células
11.
Nucleic Acids Res ; 45(17): 10002-10017, 2017 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-28973458

RESUMO

The plasticity of myeloid cells is illustrated by a diversity of functions including their role as effectors of innate immunity as macrophages (MACs) and bone remodelling as osteoclasts (OCs). TET2, a methylcytosine dioxygenase highly expressed in these cells and frequently mutated in myeloid leukemias, may be a key contributor to this plasticity. Through transcriptomic and epigenomic analyses, we investigated 5-methylcytosine (5mC), 5-hydroxymethylcytosine (5hmC) and gene expression changes in two divergent terminal myeloid differentiation processes, namely MAC and OC differentiation. MACs and OCs undergo highly similar 5hmC and 5mC changes, despite their wide differences in gene expression. Many TET2- and thymine-DNA glycosylase (TDG)-dependent 5mC and 5hmC changes directly activate the common terminal myeloid differentiation programme. However, the acquisition of differential features between MACs and OCs also depends on TET2/TDG. In fact, 5mC oxidation precedes differential histone modification changes between MACs and OCs. TET2 and TDG downregulation impairs the acquisition of such differential histone modification and expression patterns at MAC-/OC-specific genes. We prove that the histone H3K4 methyltransferase SETD1A is differentially recruited between MACs and OCs in a TET2-dependent manner. We demonstrate a novel role of these enzymes in the establishment of specific elements of identity and function in terminal myeloid differentiation.


Assuntos
Diferenciação Celular/genética , Proteínas de Ligação a DNA/genética , Epigênese Genética , Macrófagos/metabolismo , Osteoclastos/metabolismo , Proteínas Proto-Oncogênicas/genética , Timina DNA Glicosilase/genética , 5-Metilcitosina/análogos & derivados , 5-Metilcitosina/metabolismo , Linhagem da Célula/genética , Proteínas de Ligação a DNA/metabolismo , Perfilação da Expressão Gênica , Histona-Lisina N-Metiltransferase/genética , Histona-Lisina N-Metiltransferase/metabolismo , Histonas/genética , Histonas/metabolismo , Humanos , Fator Estimulador de Colônias de Macrófagos/farmacologia , Macrófagos/citologia , Macrófagos/efeitos dos fármacos , Osteoclastos/citologia , Osteoclastos/efeitos dos fármacos , Cultura Primária de Células , Proteínas Proto-Oncogênicas/metabolismo , Ligante RANK/farmacologia , Timina DNA Glicosilase/metabolismo , Transcriptoma
12.
Nat Rev Rheumatol ; 13(10): 593-605, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28905855

RESUMO

Over the past decade, awareness of the importance of epigenetic alterations in the pathogenesis of rheumatic diseases has grown in parallel with a general recognition of the fundamental role of epigenetics in the regulation of gene expression. Large-scale efforts to generate genome-wide maps of epigenetic modifications in different cell types, as well as in physiological and pathological contexts, illustrate the increasing recognition of the relevance of epigenetics. To date, although several reports have demonstrated the occurrence of epigenetic alterations in a wide range of inflammatory rheumatic conditions, epigenomic information is rarely used in a clinical setting. By contrast, several epigenetic biomarkers and treatments are currently in use for personalized therapies in patients with cancer. This Review highlights advances from the past 5 years in the field of epigenetics and their application to inflammatory rheumatic diseases, delineating the future lines of development for a rational use of epigenetic information in clinical settings and in personalized medicine. These advances include the identification of epipolymorphisms associated with clinical outcomes, DNA methylation as a contributor to disease susceptibility in rheumatic conditions, the discovery of novel epigenetic mechanisms that modulate disease susceptibility and the development of new epigenetic therapies.


Assuntos
Metilação de DNA , Doenças Reumáticas/genética , Epigênese Genética , Epigenômica , Feminino , Predisposição Genética para Doença , Humanos , Masculino
13.
Sci Rep ; 7(1): 7594, 2017 08 08.
Artigo em Inglês | MEDLINE | ID: mdl-28790320

RESUMO

Activation-induced cytidine deaminase (AID) triggers antibody diversification in B cells by catalysing deamination and subsequently mutating immunoglobulin (Ig) genes. Association of AID with RNA Pol II and occurrence of epigenetic changes during Ig gene diversification suggest participation of AID in epigenetic regulation. AID is mutated in hyper-IgM type 2 (HIGM2) syndrome. Here, we investigated the potential role of AID in the acquisition of epigenetic changes. We discovered that AID binding to the IgH locus promotes an increase in H4K20me3. In 293F cells, we demonstrate interaction between co-transfected AID and the three SUV4-20 histone H4K20 methyltransferases, and that SUV4-20H1.2, bound to the IgH switch (S) mu site, is replaced by SUV4-20H2 upon AID binding. Analysis of HIGM2 mutants shows that the AID truncated form W68X is impaired to interact with SUV4-20H1.2 and SUV4-20H2 and is unable to bind and target H4K20me3 to the Smu site. We finally show in mouse primary B cells undergoing class-switch recombination (CSR) that AID deficiency associates with decreased H4K20me3 levels at the Smu site. Our results provide a novel link between SUV4-20 enzymes and CSR and offer a new aspect of the interplay between AID and histone modifications in setting the epigenetic status of CSR sites.


Assuntos
Citidina Desaminase/genética , Epigênese Genética/imunologia , Histona-Lisina N-Metiltransferase/genética , Histonas/genética , Síndrome de Imunodeficiência com Hiper-IgM/genética , Switching de Imunoglobulina/genética , Animais , Linfócitos B/efeitos dos fármacos , Linfócitos B/imunologia , Linfócitos B/patologia , Sítios de Ligação , Linhagem Celular Tumoral , Citidina Desaminase/imunologia , Regulação da Expressão Gênica , Células HEK293 , Células HeLa , Histona-Lisina N-Metiltransferase/imunologia , Histonas/imunologia , Humanos , Síndrome de Imunodeficiência com Hiper-IgM/imunologia , Síndrome de Imunodeficiência com Hiper-IgM/patologia , Imunoglobulina G/genética , Lipopolissacarídeos/farmacologia , Ativação Linfocitária/efeitos dos fármacos , Camundongos , Camundongos Endogâmicos C57BL , Modelos Biológicos , Mutação , Ligação Proteica , RNA Polimerase II/genética , RNA Polimerase II/imunologia , Transdução de Sinais
14.
Curr Opin Pharmacol ; 35: 20-29, 2017 08.
Artigo em Inglês | MEDLINE | ID: mdl-28551408

RESUMO

Myeloid cells are extremely plastic as they respond and terminally differentiate into a plethora of functional types, in the blood or tissues, in response to a variety of growth factors, cytokines and pathogenic molecules. This plasticity is also manifested by the subversion of normal differentiation into the aberrant generation of a variety of tolerogenic myeloid cells in the tumoral microenvironment, where a variety of factors are released. Epigenetic mechanisms are in great part responsible for the plasticity of myeloid cells both under physiological and tumoral conditions. The development of compounds that inhibit epigenetic enzymes provides novel therapeutic opportunities to intercept the crosstalk between cancer cells and host myeloid cells. Here, we summarize our current knowledge on the myeloid cell types generated in the cancer environment, the factors and epigenetic enzymes participating in these processes and propose a number of potential targets for future pharmacological use.


Assuntos
Diferenciação Celular/genética , Epigênese Genética , Células Mieloides/citologia , Microambiente Tumoral/genética , Animais , Células Dendríticas/imunologia , Humanos , Macrófagos/imunologia , Osteoclastos/metabolismo , Microambiente Tumoral/imunologia
15.
Front Immunol ; 8: 318, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28382039

RESUMO

The concept of autoinflammation has evolved over the past 20 years, beginning with the discovery that mutations in the Mediterranean Fever (MEFV) gene were causative of Familial Mediterranean Fever. Currently, autoinflammatory diseases comprise a wide range of disorders with the common features of recurrent fever attacks, prevalence of hyperreactive innate immune cells, and signs of inflammation that can be systemic or organ specific in the absence of pathogenic infection of autoimmunity. Innate immune cells from the myeloid compartment are the main effectors of uncontrolled inflammation that is caused in great extent by the overproduction of inflammatory cytokines such as IL-1ß and IL-18. Defects in several signaling pathways that control innate immune defense, particularly the hyperreactivity of one or more inflammasomes, are at the core of pathologic autoinflammatory phenotypes. Although many of the autoinflammatory syndromes are known to be monogenic, some of them are genetically complex and are impacted by environmental factors. Recently, epigenetic dysregulation has surfaced as an additional contributor to pathogenesis. In the present review, we discuss data that are currently available to describe the contribution of epigenetic mechanisms in autoinflammatory diseases.

16.
J Allergy Clin Immunol ; 139(1): 202-211.e6, 2017 01.
Artigo em Inglês | MEDLINE | ID: mdl-27394913

RESUMO

BACKGROUND: Inflammasomes are cytosolic multiprotein complexes in macrophages. They assemble after infection- or stress-associated stimuli, activating both caspase-1-mediated inflammatory cytokine secretion and pyroptosis. Increased inflammasome activity resulting from gene mutations is related to monogenic autoinflammatory syndromes. However, variable penetrance among patients with the same gene mutations suggests involvement of additional mechanisms associated with inflammasome gene regulation. OBJECTIVE: We sought to investigate the role of DNA demethylation in activating inflammasome genes during macrophage differentiation and monocyte activation in healthy control subjects and patients with autoinflammatory syndrome. METHODS: Inflammasome-related genes were tested for DNA methylation and mRNA levels by using bisulfite pyrosequencing and quantitative RT-PCR in monocytes in vitro differentiated to macrophages and exposed to inflammatory conditions. The contribution of Tet methylcytosine dioxygenase 2 (TET2) and nuclear factor κB to DNA demethylation was tested by using chromatin immunoprecipitation, small interfering RNA-mediated downregulation, and pharmacologic inhibition. RESULTS: We observed that inflammasome-related genes are rapidly demethylated in both monocyte-to-macrophage differentiation and on monocyte activation. Demethylation associates with increased gene expression, and both mechanisms are impaired when TET2 and nuclear factor κB are downregulated. We analyzed DNA methylation levels of inflammasome-related genes in patients with cryopyrin-associated periodic syndromes (CAPS) and familial Mediterranean fever, 2 archetypical monogenic autoinflammatory syndromes. Under the above conditions, monocytes from untreated patients with CAPS undergo more efficient DNA demethylation than those of healthy subjects. Interestingly, patients with CAPS treated with anti-IL-1 drugs display methylation levels similar to those of healthy control subjects. CONCLUSION: Our study is the first to demonstrate the involvement of DNA methylation-associated alterations in patients with monogenic autoinflammatory disease and opens up possibilities for novel clinical markers.


Assuntos
Síndromes Periódicas Associadas à Criopirina/genética , Metilação de DNA/genética , Inflamassomos/genética , Síndromes Periódicas Associadas à Criopirina/metabolismo , Citocinas/genética , Citocinas/metabolismo , Proteínas de Ligação a DNA/genética , Febre Familiar do Mediterrâneo/genética , Febre Familiar do Mediterrâneo/metabolismo , Humanos , Macrófagos/metabolismo , Monócitos/metabolismo , NF-kappa B/metabolismo , Proteínas Proto-Oncogênicas/genética
17.
J Exp Med ; 213(12): 2591-2601, 2016 11 14.
Artigo em Inglês | MEDLINE | ID: mdl-27810920

RESUMO

Class IIa histone deacetylase (HDAC) subfamily members are tissue-specific gene repressors with crucial roles in development and differentiation processes. A prominent example is HDAC7, a class IIa HDAC that shows a lymphoid-specific expression pattern within the hematopoietic system. In this study, we explored its potential role in B cell development by generating a conditional knockout mouse model. Our study demonstrates for the first time that HDAC7 deletion dramatically blocks early B cell development and gives rise to a severe lymphopenia in peripheral organs, while also leading to pro-B cell lineage promiscuity. We find that HDAC7 represses myeloid and T lymphocyte genes in B cell progenitors through interaction with myocyte enhancer factor 2C (MEFC2). In B cell progenitors, HDAC7 is recruited to promoters and enhancers of target genes, and its absence leads to increased enrichment of histone active marks. Our results prove that HDAC7 is a bona fide transcriptional repressor essential for B cell development.


Assuntos
Linfócitos B/metabolismo , Deleção de Genes , Histona Desacetilases/metabolismo , Animais , Linhagem da Célula , Elementos Facilitadores Genéticos/genética , Código das Histonas , Histona Desacetilases/deficiência , Fatores de Transcrição MEF2/metabolismo , Camundongos , Células Precursoras de Linfócitos B/metabolismo , Regiões Promotoras Genéticas/genética
19.
Cell Metab ; 23(5): 881-92, 2016 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-27166947

RESUMO

Heart muscle maintains blood circulation, while skeletal muscle powers skeletal movement. Despite having similar myofibrilar sarcomeric structures, these striated muscles differentially express specific sarcomere components to meet their distinct contractile requirements. The mechanism responsible is still unclear. We show here that preservation of the identity of the two striated muscle types depends on epigenetic repression of the alternate lineage gene program by the chromatin remodeling complex Chd4/NuRD. Loss of Chd4 in the heart triggers aberrant expression of the skeletal muscle program, causing severe cardiomyopathy and sudden death. Conversely, genetic depletion of Chd4 in skeletal muscle causes inappropriate expression of cardiac genes and myopathy. In both striated tissues, mitochondrial function was also dependent on the Chd4/NuRD complex. We conclude that an epigenetic mechanism controls cardiac and skeletal muscle structural and metabolic identities and that loss of this regulation leads to hybrid striated muscle tissues incompatible with life.


Assuntos
Montagem e Desmontagem da Cromatina , DNA Helicases/metabolismo , Homeostase , Complexo Mi-2 de Remodelação de Nucleossomo e Desacetilase/metabolismo , Músculo Estriado/metabolismo , Envelhecimento/patologia , Animais , Cardiomiopatias/metabolismo , Cardiomiopatias/patologia , Diferenciação Celular/genética , Ilhas de CpG/genética , Regulação da Expressão Gênica no Desenvolvimento , Coração/embriologia , Camundongos Transgênicos , Mitocôndrias Cardíacas/metabolismo , Músculo Estriado/embriologia , Miócitos Cardíacos/metabolismo , Miócitos Cardíacos/patologia , Regiões Promotoras Genéticas/genética , Ligação Proteica
20.
Skelet Muscle ; 6: 9, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26981231

RESUMO

BACKGROUND: Extracellular stimuli induce gene expression responses through intracellular signaling mediators. The p38 signaling pathway is a paradigm of the mitogen-activated protein kinase (MAPK) family that, although originally identified as stress-response mediator, contributes to establishing stem cell differentiation fates. p38α is central for induction of the differentiation fate of the skeletal muscle stem cells (satellite cells) through not fully characterized mechanisms. METHODS: To investigate the global gene transcription program regulated by p38α during satellite cell differentiation (myogenesis), and to specifically address whether this regulation occurs through direct action of p38α on gene promoters, we performed a combination of microarray gene expression and genome-wide binding analyses. For experimental robustness, two myogenic cellular systems with genetic and chemical loss of p38α function were used: (1) satellite cells derived from mice with muscle-specific deletion of p38α, and (2) the C2C12 murine myoblast cell line cultured in the absence or presence of the p38α/ß inhibitor SB203580. Analyses were performed at cell proliferation and early differentiation stages. RESULTS: We show that p38α binds to a large set of active promoters during the transition of myoblasts from proliferation to differentiation stages. p38α-bound promoters are enriched with binding motifs for several transcription factors, with Sp1, Tcf3/E47, Lef1, FoxO4, MyoD, and NFATc standing out in all experimental conditions. p38α association with chromatin correlates very well with high levels of transcription, in agreement with its classical function as an activator of myogenic differentiation. Interestingly, p38α also associates with genes repressed at the onset of differentiation, thus highlighting the relevance of p38-dependent chromatin regulation for transcriptional activation and repression during myogenesis. CONCLUSIONS: These results uncover p38α association and function on chromatin at novel classes of target genes during skeletal muscle cell differentiation. This is consistent with this MAPK isoform being a transcriptional regulator.


Assuntos
Diferenciação Celular , Imunoprecipitação da Cromatina , Cromatina/metabolismo , Perfilação da Expressão Gênica , Proteína Quinase 14 Ativada por Mitógeno/metabolismo , Desenvolvimento Muscular , Células Satélites de Músculo Esquelético/enzimologia , Animais , Sítios de Ligação , Diferenciação Celular/efeitos dos fármacos , Linhagem Celular , Proliferação de Células , Perfilação da Expressão Gênica/métodos , Regulação da Expressão Gênica , Genótipo , Camundongos Knockout , Proteína Quinase 14 Ativada por Mitógeno/antagonistas & inibidores , Proteína Quinase 14 Ativada por Mitógeno/deficiência , Proteína Quinase 14 Ativada por Mitógeno/genética , Desenvolvimento Muscular/efeitos dos fármacos , Análise de Sequência com Séries de Oligonucleotídeos , Fenótipo , Regiões Promotoras Genéticas , Inibidores de Proteínas Quinases/farmacologia , Células Satélites de Músculo Esquelético/efeitos dos fármacos , Transdução de Sinais , Transcrição Genética
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