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1.
Nat Commun ; 12(1): 719, 2021 01 29.
Artigo em Inglês | MEDLINE | ID: mdl-33514712

RESUMO

The mechanisms underlying gene repression and silencers are poorly understood. Here we investigate the hypothesis that H3K27me3-rich regions of the genome, defined from clusters of H3K27me3 peaks, may be used to identify silencers that can regulate gene expression via proximity or looping. We find that H3K27me3-rich regions are associated with chromatin interactions and interact preferentially with each other. H3K27me3-rich regions component removal at interaction anchors by CRISPR leads to upregulation of interacting target genes, altered H3K27me3 and H3K27ac levels at interacting regions, and altered chromatin interactions. Chromatin interactions did not change at regions with high H3K27me3, but regions with low H3K27me3 and high H3K27ac levels showed changes in chromatin interactions. Cells with H3K27me3-rich regions knockout also show changes in phenotype associated with cell identity, and altered xenograft tumor growth. Finally, we observe that H3K27me3-rich regions-associated genes and long-range chromatin interactions are susceptible to H3K27me3 depletion. Our results characterize H3K27me3-rich regions and their mechanisms of functioning via looping.


Assuntos
Cromatina/metabolismo , Repressão Epigenética , Histonas/genética , Neoplasias/genética , Elementos Silenciadores Transcricionais/genética , Animais , Linhagem Celular Tumoral , Cromatina/genética , Sequenciamento de Cromatina por Imunoprecipitação , Feminino , Fatores de Crescimento de Fibroblastos/genética , Regulação Neoplásica da Expressão Gênica , Técnicas de Silenciamento de Genes , Técnicas de Inativação de Genes , Histonas/metabolismo , Humanos , Fator de Crescimento Insulin-Like II/genética , Camundongos , RNA-Seq , Ensaios Antitumorais Modelo de Xenoenxerto
2.
Nature ; 583(7818): 752-759, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32728242

RESUMO

Cytosine DNA methylation is essential for mammalian development but understanding of its spatiotemporal distribution in the developing embryo remains limited1,2. Here, as part of the mouse Encyclopedia of DNA Elements (ENCODE) project, we profiled 168 methylomes from 12 mouse tissues or organs at 9 developmental stages from embryogenesis to adulthood. We identified 1,808,810 genomic regions that showed variations in CG methylation by comparing the methylomes of different tissues or organs from different developmental stages. These DNA elements predominantly lose CG methylation during fetal development, whereas the trend is reversed after birth. During late stages of fetal development, non-CG methylation accumulated within the bodies of key developmental transcription factor genes, coinciding with their transcriptional repression. Integration of genome-wide DNA methylation, histone modification and chromatin accessibility data enabled us to predict 461,141 putative developmental tissue-specific enhancers, the human orthologues of which were enriched for disease-associated genetic variants. These spatiotemporal epigenome maps provide a resource for studies of gene regulation during tissue or organ progression, and a starting point for investigating regulatory elements that are involved in human developmental disorders.


Assuntos
Metilação de DNA , Epigenoma , Feto/embriologia , Feto/metabolismo , Animais , Animais Recém-Nascidos , Cromatina/genética , Cromatina/metabolismo , Doença/genética , Regulação para Baixo , Elementos Facilitadores Genéticos/genética , Repressão Epigenética , Feminino , Inativação Gênica , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Modelos Animais , Anotação de Sequência Molecular , Polimorfismo de Nucleotídeo Único , Análise Espaço-Temporal
3.
PLoS Genet ; 16(7): e1008872, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32673310

RESUMO

Transposable elements (TEs) are genomic parasites that selfishly replicate at the expense of host fitness. Fifty years of evolutionary studies of TEs have concentrated on the deleterious genetic effects of TEs, such as their effects on disrupting genes and regulatory sequences. However, a flurry of recent work suggests that there is another important source of TEs' harmful effects-epigenetic silencing. Host genomes typically silence TEs by the deposition of repressive epigenetic marks. While this silencing reduces the selfish replication of TEs and should benefit hosts, a picture is emerging that the epigenetic silencing of TEs triggers inadvertent spreading of repressive marks to otherwise expressed neighboring genes, ultimately jeopardizing host fitness. In this Review, we provide a long-overdue overview of the recent genome-wide evidence for the presence and prevalence of TEs' epigenetic effects, highlighting both the similarities and differences across mammals, insects, and plants. We lay out the current understanding of the functional and fitness consequences of TEs' epigenetic effects, and propose possible influences of such effects on the evolution of both hosts and TEs themselves. These unique evolutionary consequences indicate that TEs' epigenetic effect is not only a crucial component of TE biology but could also be a significant contributor to genome function and evolution.


Assuntos
Elementos de DNA Transponíveis/genética , Epigênese Genética , Evolução Molecular , Inativação Gênica , Animais , Repressão Epigenética/genética , Regulação da Expressão Gênica/genética , Insetos/genética , Mamíferos/genética , Plantas/genética
4.
Nat Commun ; 11(1): 3199, 2020 06 24.
Artigo em Inglês | MEDLINE | ID: mdl-32581223

RESUMO

De novo establishment of DNA methylation is accomplished by DNMT3A and DNMT3B. Here, we analyze de novo DNA methylation in mouse embryonic fibroblasts (2i-MEFs) derived from DNA-hypomethylated 2i/L ES cells with genetic ablation of Dnmt3a or Dnmt3b. We identify 355 and 333 uniquely unmethylated genes in Dnmt3a and Dnmt3b knockout (KO) 2i-MEFs, respectively. We find that Dnmt3a is exclusively required for de novo methylation at both TSS regions and gene bodies of Polycomb group (PcG) target developmental genes, while Dnmt3b has a dominant role on the X chromosome. Consistent with this, tissue-specific DNA methylation at PcG target genes is substantially reduced in Dnmt3a KO embryos. Finally, we find that human patients with DNMT3 mutations exhibit reduced DNA methylation at regions that are hypomethylated in Dnmt3 KO 2i-MEFs. In conclusion, here we report a set of unique de novo DNA methylation target sites for both DNMT3 enzymes during mammalian development that overlap with hypomethylated sites in human patients.


Assuntos
DNA (Citosina-5-)-Metiltransferases/metabolismo , Metilação de DNA , Animais , Diferenciação Celular/genética , Células Cultivadas , DNA (Citosina-5-)-Metiltransferases/genética , Repressão Epigenética/genética , Feminino , Humanos , Camundongos , Células-Tronco Embrionárias Murinas/citologia , Células-Tronco Embrionárias Murinas/metabolismo , Mutação , Especificidade de Órgãos , Proteínas do Grupo Polycomb , Sítio de Iniciação de Transcrição
5.
Nucleic Acids Res ; 48(14): 7748-7766, 2020 08 20.
Artigo em Inglês | MEDLINE | ID: mdl-32585002

RESUMO

Mouse embryonic stem cells (mESCs) cultured with MEK/ERK and GSK3ß (2i) inhibitors transition to ground state pluripotency. Gene expression changes, redistribution of histone H3K27me3 profiles and global DNA hypomethylation are hallmarks of 2i exposure, but it is unclear whether epigenetic alterations are required to achieve and maintain ground state or occur as an outcome of 2i signal induced changes. Here we show that ESCs with three epitypes, WT, constitutively methylated, or hypomethylated, all undergo comparable morphological, protein expression and transcriptome changes independently of global alterations of DNA methylation levels or changes in H3K27me3 profiles. Dazl and Fkbp6 expression are induced by 2i in all three epitypes, despite exhibiting hypermethylated promoters in constitutively methylated ESCs. We identify a number of activated gene promoters that undergo 2i dependent loss of H3K27me3 in all three epitypes, however genetic and pharmaceutical inhibition experiments show that H3K27me3 is not required for their silencing in non-2i conditions. By separating and defining their contributions, our data suggest that repressive epigenetic systems play minor roles in mESC self-renewal and naïve ground state establishment by core sets of dominant pluripotency associated transcription factor networks, which operate independently from these epigenetic processes.


Assuntos
Repressão Epigenética , Redes Reguladoras de Genes , Células-Tronco Embrionárias Murinas/metabolismo , Animais , Células Cultivadas , Metilação de DNA , Epigênese Genética , Glicogênio Sintase Quinase 3 beta/antagonistas & inibidores , Histonas/metabolismo , Masculino , Camundongos , Quinases de Proteína Quinase Ativadas por Mitógeno/antagonistas & inibidores , Células-Tronco Embrionárias Murinas/efeitos dos fármacos , Células-Tronco Embrionárias Murinas/enzimologia , Fatores de Transcrição/metabolismo , Transcrição Genética
6.
Life Sci ; 253: 117668, 2020 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-32320706

RESUMO

AIMS: Preeclampsia (PE) accounts for the foremost cause of maternal and fetal mortality worldwide, whereas, there are no effective treatments for the disease yet. Long non-coding RNAs (lncRNAs) play critical roles in various human disorders, including PE. Here, we identified an up-regulated lncRNA HOTAIR, and explored its underlying mechanisms in PE. MAIN METHODS: qRT-PCR analysis was used to examine HOTAIR expression in PE tissues and cell lines. Trophoblast proliferation was examined by colony formation and 5-Ethynyl-2'-deoxyuridine (EdU) incorporation assays. Trophoblast migration and invasion was determined by transwell and wound healing assays. Bioinformatics analysis was performed to verify the regulation HOTAIR on miRNAs. The interaction between HOTAIR and EZH2 was detected using RNA immunoprecipitation assay (RIP). Chromatin immunoprecipitation (CHIP) assay was also performed to verify that the negative regulation of HOTAIR on miR-106a was dependent on the epigenetic repressor EZH2. KEY FINDINGS: HOTAIR was up-regulated in PE placenta tissues, which repressed the proliferation, migration and invasion of trophoblast cells. HOTAIR significantly repressed miR-106a expression and the reduced miR-106a level was also observed in placentas from PE patients. Additionally, miR-106a mimic enhanced the migration and invasion of trophoblast cells. Further mechanistic analyses implied that the action of HOTAIR is moderately attributable to its repression of miR-106a via association with EZH2. SIGNIFICANCE: High level of HOTAIR repressed the proliferation, migration and invasion of trophoblast cells through targeting miR-106 in an EZH2-dependent manner, which may provide new insights into the roles of HOTAIR and miR-106a as potential regulators in PE.


Assuntos
Proteína Potenciadora do Homólogo 2 de Zeste/metabolismo , MicroRNAs/metabolismo , Pré-Eclâmpsia/metabolismo , RNA Longo não Codificante/metabolismo , Sequência de Bases , Linhagem Celular , Proliferação de Células , Progressão da Doença , Repressão Epigenética , Feminino , Humanos , Placenta/metabolismo , Gravidez , Trofoblastos/citologia , Regulação para Cima
8.
Cancer Res ; 80(8): 1644-1655, 2020 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-32094299

RESUMO

Glioblastoma multiforme (GBM) and other solid malignancies are heterogeneous and contain subpopulations of tumor cells that exhibit stem-like features. Our recent findings point to a dedifferentiation mechanism by which reprogramming transcription factors Oct4 and Sox2 drive the stem-like phenotype in glioblastoma, in part, by differentially regulating subsets of miRNAs. Currently, the molecular mechanisms by which reprogramming transcription factors and miRNAs coordinate cancer stem cell tumor-propagating capacity are unclear. In this study, we identified miR-486-5p as a Sox2-induced miRNA that targets the tumor suppressor genes PTEN and FoxO1 and regulates the GBM stem-like cells. miR-486-5p associated with the GBM stem cell phenotype and Sox2 expression and was directly induced by Sox2 in glioma cell lines and patient-derived neurospheres. Forced expression of miR-486-5p enhanced the self-renewal capacity of GBM neurospheres, and inhibition of endogenous miR-486-5p activated PTEN and FoxO1 and induced cell death by upregulating proapoptotic protein BIM via a PTEN-dependent mechanism. Furthermore, delivery of miR-486-5p antagomirs to preestablished orthotopic GBM neurosphere-derived xenografts using advanced nanoparticle formulations reduced tumor sizes in vivo and enhanced the cytotoxic response to ionizing radiation. These results define a previously unrecognized and therapeutically targetable Sox2:miR-486-5p axis that enhances the survival of GBM stem cells by repressing tumor suppressor pathways. SIGNIFICANCE: This study identifies a novel axis that links core transcriptional drivers of cancer cell stemness to miR-486-5p-dependent modulation of tumor suppressor genes that feeds back to regulate glioma stem cell survival.


Assuntos
Neoplasias Encefálicas/patologia , Sobrevivência Celular , Proteína Forkhead Box O1/genética , Genes Supressores de Tumor , Glioblastoma/patologia , MicroRNAs/metabolismo , Proteínas de Neoplasias/fisiologia , PTEN Fosfo-Hidrolase/genética , Fatores de Transcrição SOXB1/fisiologia , Animais , Proteína 11 Semelhante a Bcl-2/metabolismo , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/metabolismo , Neoplasias Encefálicas/radioterapia , Morte Celular , Desdiferenciação Celular/genética , Linhagem Celular Tumoral , Reprogramação Celular/fisiologia , Repressão Epigenética , Feminino , Regulação Neoplásica da Expressão Gênica , Glioblastoma/genética , Glioblastoma/metabolismo , Glioblastoma/radioterapia , Xenoenxertos , Humanos , Camundongos , Camundongos Nus , MicroRNAs/administração & dosagem , MicroRNAs/antagonistas & inibidores , MicroRNAs/genética , Nanopartículas/administração & dosagem , Proteínas de Neoplasias/genética , Células-Tronco Neoplásicas/metabolismo , Células-Tronco Neoplásicas/patologia , Células-Tronco Neoplásicas/efeitos da radiação , Células-Tronco Neurais , Fator 3 de Transcrição de Octâmero/metabolismo , Tolerância a Radiação , Distribuição Aleatória , Fatores de Transcrição SOXB1/genética , Fatores de Transcrição SOXB1/metabolismo , Transfecção/métodos , Carga Tumoral , Ensaio Tumoral de Célula-Tronco/métodos , Regulação para Cima
9.
J Med Chem ; 63(2): 676-695, 2020 01 23.
Artigo em Inglês | MEDLINE | ID: mdl-31895575

RESUMO

The transcriptional repressor B-cell lymphoma 6 (BCL6) is frequently misregulated in diffuse large B-cell lymphoma (DLBCL) and has emerged as an attractive drug target for the treatments of lymphoma. In this article, a series of N-phenyl-4-pyrimidinamine derivatives were designed and synthesized as potent BCL6 inhibitors by optimizing hit compound N4-(3-chloro-4-methoxyphenyl)-N2-isobutyl-5-fluoro-2,4-pyrimidinediamine on the basis of the structure-activity relationship. Among them, compound 14j displayed the most potent activities, which significantly blocked the interaction of BCL6 with its corepressors, reactivated BCL6 target genes in a dose-dependent manner, and had better effects compared with the two positive controls. Further studies indicated that a low dose of 14j could effectively inhibit germinal center formation. More importantly, 14j not only showed potent inhibition of DLBCL cell proliferation in vitro but also strongly suppressed the growth of DLBCL in vivo.


Assuntos
Antineoplásicos/síntese química , Antineoplásicos/farmacologia , Linfoma Difuso de Grandes Células B/tratamento farmacológico , Proteínas Proto-Oncogênicas c-bcl-6/antagonistas & inibidores , Pirimidinas/síntese química , Pirimidinas/farmacologia , Animais , Apoptose/efeitos dos fármacos , Proliferação de Células , Relação Dose-Resposta a Droga , Repressão Epigenética/efeitos dos fármacos , Centro Germinativo/efeitos dos fármacos , Células HEK293 , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Modelos Moleculares , Simulação de Acoplamento Molecular , Proteínas Proto-Oncogênicas c-bcl-6/genética , Relação Estrutura-Atividade , Ensaios Antitumorais Modelo de Xenoenxerto
10.
Cancer Res ; 80(2): 276-290, 2020 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-31694906

RESUMO

The tumor-promoting fibrotic stroma rich in tumor-associated fibroblasts (TAF) is drawing increased therapeutic attention. Intriguingly, a trial with the antifibrotic drug nintedanib in non-small cell lung cancer reported clinical benefits in adenocarcinoma (ADC) but not squamous cell carcinoma (SCC), even though the stroma is fibrotic in both histotypes. Likewise, we reported that nintedanib inhibited the tumor-promoting fibrotic phenotype of TAFs selectively in ADC. Here we show that tumor fibrosis is actually higher in ADC-TAFs than SCC-TAFs in vitro and patient samples. Mechanistically, the reduced fibrosis and nintedanib response of SCC-TAFs was associated with increased promoter methylation of the profibrotic TGFß transcription factor SMAD3 compared with ADC-TAFs, which elicited a compensatory increase in TGFß1/SMAD2 activation. Consistently, forcing global DNA demethylation of SCC-TAFs with 5-AZA rescued TGFß1/SMAD3 activation, whereas genetic downregulation of SMAD3 in ADC-TAFs and control fibroblasts increased TGFß1/SMAD2 activation, and reduced their fibrotic phenotype and antitumor responses to nintedanib in vitro and in vivo. Our results also support that smoking and/or the anatomic location of SCC in the proximal airways, which are more exposed to cigarette smoke particles, may prime SCC-TAFs to stronger SMAD3 epigenetic repression, because cigarette smoke condensate selectively increased SMAD3 promoter methylation. Our results unveil that the histotype-specific regulation of tumor fibrosis in lung cancer is mediated through differential SMAD3 promoter methylation in TAFs and provide new mechanistic insights on the selective poor response of SCC-TAFs to nintedanib. Moreover, our findings support that patients with ADC may be more responsive to antifibrotic drugs targeting their stromal TGFß1/SMAD3 activation. SIGNIFICANCE: This study implicates the selective epigenetic repression of SMAD3 in SCC-TAFs in the clinical failure of nintedanib in SCC and supports that patients with ADC may benefit from antifibrotic drugs targeting stromal TGFß1/SMAD3.


Assuntos
Adenocarcinoma de Pulmão/tratamento farmacológico , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Resistencia a Medicamentos Antineoplásicos/genética , Indóis/farmacologia , Neoplasias Pulmonares/tratamento farmacológico , Proteína Smad3/genética , Adenocarcinoma de Pulmão/genética , Adenocarcinoma de Pulmão/patologia , Adenocarcinoma de Pulmão/cirurgia , Idoso , Idoso de 80 Anos ou mais , Animais , Fibroblastos Associados a Câncer/efeitos dos fármacos , Fibroblastos Associados a Câncer/patologia , Carcinoma Pulmonar de Células não Pequenas/genética , Carcinoma Pulmonar de Células não Pequenas/patologia , Carcinoma Pulmonar de Células não Pequenas/cirurgia , Estudos de Coortes , Metilação de DNA/genética , Repressão Epigenética , Feminino , Fibrose , Regulação Neoplásica da Expressão Gênica , Humanos , Indóis/uso terapêutico , Pulmão/citologia , Pulmão/efeitos dos fármacos , Pulmão/patologia , Pulmão/cirurgia , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/patologia , Neoplasias Pulmonares/cirurgia , Masculino , Camundongos , Pessoa de Meia-Idade , Pneumonectomia , Regiões Promotoras Genéticas/genética , Proteína Smad2/genética , Proteína Smad2/metabolismo , Proteína Smad3/metabolismo , Análise Serial de Tecidos , Ensaios Antitumorais Modelo de Xenoenxerto
11.
J Med Chem ; 63(2): 656-675, 2020 01 23.
Artigo em Inglês | MEDLINE | ID: mdl-31858797

RESUMO

WD repeat domain 5 (WDR5) is a member of the WD40-repeat protein family that plays a critical role in multiple chromatin-centric processes. Overexpression of WDR5 correlates with a poor clinical outcome in many human cancers, and WDR5 itself has emerged as an attractive target for therapy. Most drug-discovery efforts center on the WIN site of WDR5 that is responsible for the recruitment of WDR5 to chromatin. Here, we describe discovery of a novel WDR5 WIN site antagonists containing a dihydroisoquinolinone bicyclic core using a structure-based design. These compounds exhibit picomolar binding affinity and selective concentration-dependent antiproliferative activities in sensitive MLL-fusion cell lines. Furthermore, these WDR5 WIN site binders inhibit proliferation in MYC-driven cancer cells and reduce MYC recruitment to chromatin at MYC/WDR5 co-bound genes. Thus, these molecules are useful probes to study the implication of WDR5 inhibition in cancers and serve as a potential starting point toward the discovery of anti-WDR5 therapeutics.


Assuntos
Antineoplásicos/síntese química , Antineoplásicos/farmacologia , Compostos Bicíclicos Heterocíclicos com Pontes/síntese química , Compostos Bicíclicos Heterocíclicos com Pontes/farmacologia , Peptídeos e Proteínas de Sinalização Intracelular/antagonistas & inibidores , Quinolonas/síntese química , Quinolonas/farmacologia , Repetições WD40/efeitos dos fármacos , Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células , Cromatina/efeitos dos fármacos , Cromatina/genética , Cristalografia por Raios X , Desenho de Fármacos , Descoberta de Drogas , Repressão Epigenética/efeitos dos fármacos , Genes myc/efeitos dos fármacos , Humanos , Relação Estrutura-Atividade
12.
Cell ; 180(1): 150-164.e15, 2020 01 09.
Artigo em Inglês | MEDLINE | ID: mdl-31883795

RESUMO

In eukaryotes, heterochromatin is generally located at the nuclear periphery. This study investigates the biological significance of perinuclear positioning for heterochromatin maintenance and gene silencing. We identify the nuclear rim protein Amo1NUPL2 as a factor required for the propagation of heterochromatin at endogenous and ectopic sites in the fission yeast genome. Amo1 associates with the Rix1PELP1-containing RNA processing complex RIXC and with the histone chaperone complex FACT. RIXC, which binds to heterochromatin protein Swi6HP1 across silenced chromosomal domains and to surrounding boundary elements, connects heterochromatin with Amo1 at the nuclear periphery. In turn, the Amo1-enriched subdomain is critical for Swi6 association with FACT that precludes histone turnover to promote gene silencing and preserve epigenetic stability of heterochromatin. In addition to uncovering conserved factors required for perinuclear positioning of heterochromatin, these analyses elucidate a mechanism by which a peripheral subdomain enforces stable gene repression and maintains heterochromatin in a heritable manner.


Assuntos
Epigênese Genética/genética , Heterocromatina/genética , Heterocromatina/metabolismo , Proteínas de Ciclo Celular/metabolismo , Núcleo Celular/metabolismo , Proteínas Cromossômicas não Histona/metabolismo , Repressão Epigenética/genética , Inativação Gênica , Hereditariedade , Histonas/genética , Histonas/metabolismo , Metilação , Proteínas Nucleares/metabolismo , Schizosaccharomyces/genética , Schizosaccharomyces/metabolismo , Proteínas de Schizosaccharomyces pombe/genética , Proteínas de Schizosaccharomyces pombe/metabolismo
13.
Exp Eye Res ; 190: 107886, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31759996

RESUMO

Diabetic retinopathy (DR) is a microvascular complication of diabetes and one of the most common causes of blindness in active stage. This study is performed to explore the effects of microRNA-21 (miR-21) on retinal vascular endothelial cell (RVEC) viability and angiogenesis in rats with DR via the phosphatidylinositiol 3-kinase/protein kinase B (PI3K/Akt)/vascular endothelial growth factor (VEGF) signaling pathway by binding to phosphatase and tensin homolog (PTEN). Sprague Dawley (SD) rats were used for establishment of DR models. Target relationship between miR-21 and PTEN was assessed by bioinformatics prediction in combination with dual-luciferase reporter gene assay. Identification of expression of miR-21, PTEN and PI3K/Akt/VEGF signaling pathway-related genes in the retinal tissues was then conducted. In order to assess the contributory role of miR-21 in DR, the RVECs were transfected with mimic or inhibitor of miR-21, or siRNA-PTEN, followed by the detection of expression of PTEN and PI3K/Akt/VEGF-related genes, as well as the measurement of cell viability, cell cycle and apoptosis. Increased expression of miR-21 and PI3K/Akt/VEGF related genes, along with a reduced expression of PTEN was observed in the retinal tissues of DR rats. PTEN was targeted and negatively regulated by miR-21, while the PI3K/Akt/VEGF signaling pathway was activated by miR-21. RVECs transfected with miR-21 inhibitor exhibited promoted viability and angiogenesis, and inhibited apoptosis. To conclude, our results indicated that miR-21 overexpression could potentially stimulate RVEC viability and angiogenesis in rats with DR through activation of the PI3K/Akt/VEGF signaling pathway via repressing PTEN expression, highlighting the potential of miR-21 as a target for DR treatment.


Assuntos
Retinopatia Diabética/metabolismo , Células Endoteliais/patologia , MicroRNAs/genética , Neovascularização Patológica/prevenção & controle , PTEN Fosfo-Hidrolase/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Fator A de Crescimento do Endotélio Vascular/metabolismo , Animais , Apoptose , Western Blotting , Proliferação de Células , Diabetes Mellitus Experimental/genética , Diabetes Mellitus Experimental/metabolismo , Retinopatia Diabética/genética , Células Endoteliais/metabolismo , Repressão Epigenética/fisiologia , Citometria de Fluxo , Imuno-Histoquímica , Masculino , Neovascularização Patológica/metabolismo , Fosfatidilinositol 3-Quinases/genética , Proteínas Proto-Oncogênicas c-akt/genética , Ratos , Ratos Sprague-Dawley , Vasos Retinianos/patologia , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transdução de Sinais/fisiologia , Transfecção , Fator A de Crescimento do Endotélio Vascular/genética
14.
Nat Commun ; 10(1): 4964, 2019 10 31.
Artigo em Inglês | MEDLINE | ID: mdl-31673027

RESUMO

Plasmodium sporozoites are transmitted from infected mosquitoes to mammals, and must navigate the host skin and vasculature to infect the liver. This journey requires distinct proteomes. Here, we report the dynamic transcriptomes and proteomes of both oocyst sporozoites and salivary gland sporozoites in both rodent-infectious Plasmodium yoelii parasites and human-infectious Plasmodium falciparum parasites. The data robustly define mRNAs and proteins that are upregulated in oocyst sporozoites (UOS) or upregulated in infectious sporozoites (UIS) within the salivary glands, including many that are essential for sporozoite functions in the vector and host. Moreover, we find that malaria parasites use two overlapping, extensive, and independent programs of translational repression across sporozoite maturation to temporally regulate protein expression. Together with gene-specific validation experiments, these data indicate that two waves of translational repression are implemented and relieved at different times during sporozoite maturation, migration and infection, thus promoting their successful development and vector-to-host transition.


Assuntos
Regulação da Expressão Gênica no Desenvolvimento/genética , Oocistos/genética , Plasmodium falciparum/genética , Plasmodium yoelii/genética , Proteoma/metabolismo , RNA Mensageiro/metabolismo , Esporozoítos/genética , Transcriptoma/genética , Animais , Anopheles/parasitologia , Cromatografia Líquida , Repressão Epigenética/genética , Perfilação da Expressão Gênica , Humanos , Malária , Malária Falciparum , Mosquitos Vetores/parasitologia , Oocistos/metabolismo , Plasmodium falciparum/metabolismo , Plasmodium yoelii/metabolismo , Proteômica , Roedores , Glândulas Salivares/parasitologia , Esporozoítos/metabolismo , Espectrometria de Massas em Tandem , Regulação para Cima
15.
Nat Commun ; 10(1): 5324, 2019 11 22.
Artigo em Inglês | MEDLINE | ID: mdl-31757943

RESUMO

Most cancers are resistant to anti-PD-1/PD-L1 and chemotherapy. Herein we identify PDLIM2 as a tumor suppressor particularly important for lung cancer therapeutic responses. While PDLIM2 is epigenetically repressed in human lung cancer, associating with therapeutic resistance and poor prognosis, its global or lung epithelial-specific deletion in mice causes increased lung cancer development, chemoresistance, and complete resistance to anti-PD-1 and epigenetic drugs. PDLIM2 epigenetic restoration or ectopic expression shows antitumor activity, and synergizes with anti-PD-1, notably, with chemotherapy for complete remission of most lung cancers. Mechanistically, through repressing NF-κB/RelA and STAT3, PDLIM2 increases expression of genes involved in antigen presentation and T-cell activation while repressing multidrug resistance genes and cancer-related genes, thereby rendering cancer cells vulnerable to immune attacks and therapies. We identify PDLIM2-independent PD-L1 induction by chemotherapeutic and epigenetic drugs as another mechanism for their synergy with anti-PD-1. These findings establish a rationale to use combination therapies for cancer treatment.


Assuntos
Repressão Epigenética/genética , Regulação Neoplásica da Expressão Gênica , Proteínas com Domínio LIM/genética , Neoplasias Pulmonares/genética , Proteínas dos Microfilamentos/genética , Proteínas Adaptadoras de Transdução de Sinal/genética , Animais , Antineoplásicos Imunológicos/uso terapêutico , Antígeno B7-H1/antagonistas & inibidores , Linhagem Celular Tumoral , Metilação de DNA , Modelos Animais de Doenças , Resistencia a Medicamentos Antineoplásicos/genética , Técnicas de Silenciamento de Genes , Genes Supressores de Tumor , Humanos , Neoplasias Pulmonares/tratamento farmacológico , Camundongos , Camundongos Knockout , Receptor de Morte Celular Programada 1/antagonistas & inibidores , Regiões Promotoras Genéticas , Proteínas Proto-Oncogênicas p21(ras)/genética , Fator de Transcrição STAT3/genética , Fator de Transcrição RelA/genética
16.
Essays Biochem ; 63(6): 677-689, 2019 12 20.
Artigo em Inglês | MEDLINE | ID: mdl-31654072

RESUMO

Transposable elements dominate the mammalian genome, but their contribution to genetic and epigenetic regulation has been largely overlooked. This was in part due to technical limitations, which made the study of repetitive sequences at single copy resolution difficult. The advancement of next-generation sequencing assays in the last decade has greatly enhanced our understanding of transposable element function. In some instances, specific transposable elements are thought to have been co-opted into regulatory roles during both mouse and human development, while in disease such regulatory potential can contribute to malignancy. DNA methylation is arguably the best characterised regulator of transposable element activity. DNA methylation is associated with transposable element repression, and acts to limit their genotoxic potential. In specific developmental contexts, erasure of DNA methylation is associated with a burst of transposable element expression. Developmental regulation of DNA methylation enables transposon activation, ensuring their survival and propagation throughout the host genome, and also allows the host access to regulatory sequences encoded within the elements. Here I discuss DNA methylation at transposable elements, describing its function and dynamic regulation throughout murine and human development.


Assuntos
Metilação de DNA/fisiologia , Elementos de DNA Transponíveis/fisiologia , Animais , Repressão Epigenética/fisiologia , Humanos
17.
Cancer Cell ; 36(4): 385-401.e8, 2019 10 14.
Artigo em Inglês | MEDLINE | ID: mdl-31564637

RESUMO

Loss of MHC class I (MHC-I) antigen presentation in cancer cells can elicit immunotherapy resistance. A genome-wide CRISPR/Cas9 screen identified an evolutionarily conserved function of polycomb repressive complex 2 (PRC2) that mediates coordinated transcriptional silencing of the MHC-I antigen processing pathway (MHC-I APP), promoting evasion of T cell-mediated immunity. MHC-I APP gene promoters in MHC-I low cancers harbor bivalent activating H3K4me3 and repressive H3K27me3 histone modifications, silencing basal MHC-I expression and restricting cytokine-induced upregulation. Bivalent chromatin at MHC-I APP genes is a normal developmental process active in embryonic stem cells and maintained during neural progenitor differentiation. This physiological MHC-I silencing highlights a conserved mechanism by which cancers arising from these primitive tissues exploit PRC2 activity to enable immune evasion.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Regulação Neoplásica da Expressão Gênica/imunologia , Antígenos de Histocompatibilidade Classe I/genética , Neoplasias/imunologia , Complexo Repressor Polycomb 2/metabolismo , Evasão Tumoral/genética , Animais , Apresentação do Antígeno/efeitos dos fármacos , Apresentação do Antígeno/imunologia , Antineoplásicos Imunológicos/farmacologia , Antineoplásicos Imunológicos/uso terapêutico , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Linhagem Celular Tumoral , Metilação de DNA/imunologia , Regulação para Baixo/efeitos dos fármacos , Regulação para Baixo/genética , Regulação para Baixo/imunologia , Resistencia a Medicamentos Antineoplásicos/genética , Repressão Epigenética/efeitos dos fármacos , Repressão Epigenética/imunologia , Feminino , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Antígenos de Histocompatibilidade Classe I/imunologia , Antígenos de Histocompatibilidade Classe I/metabolismo , Código das Histonas/efeitos dos fármacos , Humanos , Camundongos , Pessoa de Meia-Idade , Neoplasias/tratamento farmacológico , Neoplasias/genética , Neoplasias/patologia , Complexo Repressor Polycomb 2/antagonistas & inibidores , Linfócitos T/imunologia , Evasão Tumoral/efeitos dos fármacos , Ensaios Antitumorais Modelo de Xenoenxerto
18.
Antiviral Res ; 172: 104619, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31600533

RESUMO

Hepatitis B virus (HBV) infection remains an important public health problem worldwide. Covalently closed circular DNA (cccDNA) exhibits as an individual minichromosome and is the molecular basis of HBV infection persistence and antiviral treatment failure. In the current study, we demonstrated that histone deacetylase 11 (HDAC11) inhibits HBV transcription and replication in HBV-transfected Huh7 cells. By using an HBV in vitro infection system, HDAC11 was found to affect the transcriptional activity of cccDNA but did not affect cccDNA production. Chromatin immunoprecipitation (ChIP) assays were utilized to analyze the epigenetic modifications of cccDNA. The results show that HDAC11 specifically reduced the acetylation level of cccDNA-bound histone H3 but did not affect that of histone H4. Furthermore, HDAC11 overexpression decreased the levels of cccDNA-bound acetylated H3K9 (H3K9ac) and H3K27 (H3K27ac). In conclusion, HDAC11 restricts HBV replication through epigenetic repression of cccDNA transcription. These findings reveal the novel role of HDAC11 in HBV infection, further broadening our knowledge regarding the functions of HDAC11 and the roles of HDACs in the epigenetic regulation of HBV cccDNA.


Assuntos
Repressão Epigenética , Vírus da Hepatite B/genética , Histona Desacetilases/metabolismo , Replicação Viral/genética , Linhagem Celular , DNA Circular/metabolismo , DNA Viral/metabolismo , Epigênese Genética , Hepatite B/metabolismo , Hepatite B/virologia , Histonas/metabolismo , Humanos , Transcrição Genética
19.
FASEB J ; 33(12): 13982-13997, 2019 12.
Artigo em Inglês | MEDLINE | ID: mdl-31645134

RESUMO

The efficiency of somatic cell nuclear transfer (SCNT) reprogramming is extremely low in terms of production of cloned animals. Here, we found that telomere rejuvenation is a critical event for SCNT reprogramming. Through small-molecule screening, we identified that melatonin significantly improved the in vitro and in vivo developmental competence of SCNT-derived embryos. Through use of embryonic biopsy, single-cell RNA sequencing, and quantitative FISH experiments, we revealed that melatonin not only attenuated the zygotic genome activation defect but also facilitated telomere elongation in the SCNT embryos. Further investigation indicated that melatonin inhibited heterochromatic epigenetic modification related to gene silencing including DNA methylation and histone H3 lysine 9 trimethylation. In addition, melatonin could increase the level of activation markers such as acetylated histone H3. This is the first study to characterize melatonin-treatment and telomere rejuvenation in SCNT-mediated reprogramming. Moreover, combinational use of melatonin-treated donor embryos and pseudopregnant recipients achieved synergistic enhancement of the production of cloned animals.-Yang, L., Liu, X., Song, L., Su, G., Di, A., Bai, C., Wei, Z., Li, G. Inhibiting repressive epigenetic modification promotes telomere rejuvenation in somatic cell reprogramming.


Assuntos
Reprogramação Celular , Embrião de Mamíferos/efeitos dos fármacos , Repressão Epigenética/efeitos dos fármacos , Telômero/fisiologia , Animais , Clonagem de Organismos , Técnicas de Cultura Embrionária , Desenvolvimento Embrionário/efeitos dos fármacos , Melatonina/farmacologia , Camundongos , Estresse Oxidativo/efeitos dos fármacos
20.
Cell Stem Cell ; 25(4): 514-530.e8, 2019 10 03.
Artigo em Inglês | MEDLINE | ID: mdl-31543366

RESUMO

Cellular senescence is a mechanism used by mitotic cells to prevent uncontrolled cell division. As senescent cells persist in tissues, they cause local inflammation and are harmful to surrounding cells, contributing to aging. Generally, neurodegenerative diseases, such as Parkinson's, are disorders of aging. The contribution of cellular senescence to neurodegeneration is still unclear. SATB1 is a DNA binding protein associated with Parkinson's disease. We report that SATB1 prevents cellular senescence in post-mitotic dopaminergic neurons. Loss of SATB1 causes activation of a cellular senescence transcriptional program in dopamine neurons both in human stem cell-derived dopaminergic neurons and in mice. We observed phenotypes that are central to cellular senescence in SATB1 knockout dopamine neurons in vitro and in vivo. Moreover, we found that SATB1 directly represses expression of the pro-senescence factor p21 in dopaminergic neurons. Our data implicate senescence of dopamine neurons as a contributing factor in the pathology of Parkinson's disease.


Assuntos
Envelhecimento/fisiologia , Inibidor de Quinase Dependente de Ciclina p21/metabolismo , Neurônios Dopaminérgicos/fisiologia , Proteínas de Ligação à Região de Interação com a Matriz/metabolismo , Doença de Parkinson/metabolismo , Animais , Células Cultivadas , Senescência Celular , Inibidor de Quinase Dependente de Ciclina p21/genética , Repressão Epigenética , Técnicas de Silenciamento de Genes , Humanos , Proteínas de Ligação à Região de Interação com a Matriz/genética , Camundongos , Camundongos Knockout , Mitose , Doença de Parkinson/genética , Ligação Proteica
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