RESUMO
Chromatin loops juxtapose distal enhancers with active promoters, but their molecular architecture and relationship with transcription remain unclear. In erythroid cells, the locus control region (LCR) and ß-globin promoter form a chromatin loop that requires transcription factor GATA1 and the associated molecule Ldb1. We employed artificial zinc fingers (ZF) to tether Ldb1 to the ß-globin promoter in GATA1 null erythroblasts, in which the ß-globin locus is relaxed and inactive. Remarkably, targeting Ldb1 or only its self-association domain to the ß-globin promoter substantially activated ß-globin transcription in the absence of GATA1. Promoter-tethered Ldb1 interacted with endogenous Ldb1 complexes at the LCR to form a chromatin loop, causing recruitment and phosphorylation of RNA polymerase II. ZF-Ldb1 proteins were inactive at alleles lacking the LCR, demonstrating that their activities depend on long-range interactions. Our findings establish Ldb1 as a critical effector of GATA1-mediated loop formation and indicate that chromatin looping causally underlies gene regulation.
Assuntos
Cromatina/metabolismo , Proteínas de Ligação a DNA/metabolismo , Proteínas com Domínio LIM/metabolismo , Transcrição Gênica , Globinas beta/genética , Animais , Linhagem Celular , Separação Celular , Proteínas de Ligação a DNA/química , Embrião de Mamíferos/citologia , Eritroblastos/metabolismo , Feminino , Fator de Transcrição GATA1/metabolismo , Regulação da Expressão Gênica , Proteínas com Domínio LIM/química , Masculino , Camundongos , Regiões Promotoras Genéticas , Estrutura Terciária de Proteína , Dedos de ZincoRESUMO
Long noncoding RNAs (lncRNAs) are increasingly being appreciated as participants in regulation of important cellular processes, including transcription. Because lncRNAs are highly cell type specific, they have the potential to contribute to the unique transcriptional repertoire of diverse cells, but underlying mechanisms are unclear. We studied BGLT3, an erythroid lncRNA encoded downstream of Aγ-globin (HBG1). BGLT3 and γ-globin genes are dynamically cotranscribed in erythroid cells in vivo. Deletion of BGLT3 using CRISPR/Cas9 editing shows that it specifically contributes to regulation of γ-globin genes. We used reduction or overexpression of the RNA and inhibition of transcription through the locus by CRISPRi to distinguish functions of the transcript vs the underlying sequence. Transcription of the BGLT3 locus is critical for looping between the γ-globin genes and BGLT3 sequences. In contrast, the BGLT3 transcript is dispensable for γ-globin/BGLT3 looping but interacts with the mediator complex on chromatin. Manipulation of the BGLT3 locus does not compromise γ-globin gene long-range looping interactions with the ß-globin locus control region (LCR). These data reveal that BGLT3 regulates γ-globin transcription in a developmental stage-specific fashion together with the LCR by serving as a separate means to increase RNA Pol II density at the γ-globin promoters.
Assuntos
Região de Controle de Locus Gênico , RNA Longo não Codificante/genética , gama-Globinas/genética , Animais , Sistemas CRISPR-Cas , Linhagem Celular , Células Eritroides/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Humanos , Camundongos TransgênicosRESUMO
BACKGROUND AND AIMS: CD4+CD25+Foxp3+ T-regulatory (Treg) cells control immune responses and maintain immune homeostasis. However, under inflammatory conditions, Treg cells produce cytokines that promote inflammation. We investigated production of tumor necrosis factor (TNF) by Treg cells in patients with acute hepatitis A (AHA), and examined the characteristics of these cells and association with clinical factors. METHODS: We analyzed blood samples collected from 63 patients with AHA at the time of hospitalization (and some at later time points) and 19 healthy donors in South Korea. Liver tissues were collected from patients with fulminant AHA during liver transplantation. Peripheral blood mononuclear cells were isolated from whole blood and lymphocytes were isolated from liver tissues and analyzed by flow cytometry. Cytokine production from Treg cells (CD4+CD25+Foxp3+) was measured by immunofluorescence levels following stimulation with anti-CD3 and anti-CD28. Epigenetic stability of Treg cells was determined based on DNA methylation patterns. Phenotypes of Treg cells were analyzed by flow cytometry and an RORγt inhibitor, ML-209, was used to inhibit TNF production. Treg cell suppression assay was performed by co-culture of Treg-depleted peripheral blood mononuclear cells s and isolated Treg cells. RESULTS: A higher proportion of CD4+CD25+Foxp3+ Treg cells from patients with AHA compared with controls produced TNF upon stimulation with anti-CD3 and anti-CD28 (11.2% vs 2.8%). DNA methylation analysis confirmed the identity of the Treg cells. TNF-producing Treg cells had features of T-helper 17 cells, including up-regulation of RORγt, which was required for TNF production. The Treg cells had reduced suppressive functions compared with Treg cells from controls. The frequency of TNF-producing Treg cells in AHA patients' blood correlated with their serum level of alanine aminotransferase. CONCLUSIONS: Treg cells from patients with AHA have altered functions compared with Treg cells from healthy individuals. Treg cells from patients with AHA produce higher levels of TNF, gain features of T-helper 17 cells, and have reduced suppressive activity. The presence of these cells is associated with severe liver injury in patients with AHA.
Assuntos
Hepatite A/metabolismo , Fígado/metabolismo , Linfócitos T Reguladores/metabolismo , Fator de Necrose Tumoral alfa/metabolismo , Doença Aguda , Antígenos CD/imunologia , Antígenos CD/metabolismo , Apirase/imunologia , Apirase/metabolismo , Estudos de Casos e Controles , Células Cultivadas , Metilação de DNA , Epigênese Genética , Fatores de Transcrição Forkhead/imunologia , Fatores de Transcrição Forkhead/metabolismo , Hepatite A/diagnóstico , Hepatite A/imunologia , Hepatite A/virologia , Vírus da Hepatite A/imunologia , Vírus da Hepatite A/patogenicidade , Interações Hospedeiro-Patógeno , Humanos , Subunidade alfa de Receptor de Interleucina-2/imunologia , Subunidade alfa de Receptor de Interleucina-2/metabolismo , Fígado/imunologia , Fígado/patologia , Fígado/virologia , Membro 3 do Grupo F da Subfamília 1 de Receptores Nucleares/imunologia , Membro 3 do Grupo F da Subfamília 1 de Receptores Nucleares/metabolismo , Fenótipo , Índice de Gravidade de Doença , Transdução de Sinais , Linfócitos T Reguladores/imunologia , Linfócitos T Reguladores/virologia , Células Th17/imunologia , Células Th17/metabolismo , Células Th17/virologia , Fatores de Tempo , Fator de Necrose Tumoral alfa/imunologiaRESUMO
IL-21, a pleiotropic cytokine strongly linked with autoimmunity and inflammation, regulates diverse immune responses. IL-21 can be potently induced in CD4(+) T cells by IL-6; however, very little is known about the mechanisms underlying the transcriptional regulation of the Il21 gene at the chromatin level. In this study, we demonstrated that a conserved noncoding sequence located 49 kb upstream of the Il21 gene contains an enhancer element that can upregulate Il21 gene expression in a STAT3- and NFAT-dependent manner. Additionally, we identified enhancer-blocking insulator elements in the Il21 locus, which constitutively bind CTCF and cohesin. In naive CD4(+) T cells, these upstream and downstream CTCF binding sites interact with each other to make a DNA loop; however, the Il21 promoter does not interact with any cis-elements in the Il21 locus. In contrast, stimulation of CD4(+) T cells with IL-6 leads to recruitment of STAT3 to the promoter and novel distal enhancer region. This induces dynamic changes in chromatin configuration, bringing the promoter and the regulatory elements in close spatial proximity. The long-range interaction between the promoter and distal enhancer region was dependent on IL-6/STAT3 signaling pathway but was disrupted in regulatory T cells, where IL-21 expression was repressed. Thus, our work uncovers a novel topological chromatin framework underlying proper transcriptional regulation of the Il21 gene.
Assuntos
Linfócitos T CD4-Positivos/metabolismo , Cromatina/genética , Proteínas de Ligação a DNA/genética , Interleucinas/genética , Animais , Sequência de Bases , Fator de Ligação a CCCTC , Proteínas de Ciclo Celular/metabolismo , Proteínas Cromossômicas não Histona/metabolismo , Sequência Conservada , Elementos Facilitadores Genéticos , Regulação da Expressão Gênica , Humanos , Interleucina-6/farmacologia , Camundongos , Camundongos Endogâmicos C57BL , Fatores de Transcrição NFATC/metabolismo , Regiões Promotoras Genéticas , Proteínas Repressoras/genética , Proteínas Repressoras/metabolismo , Fator de Transcrição STAT3/metabolismo , Transdução de Sinais , CoesinasRESUMO
PURPOSE: To determine the repeatability of measuring the thickness of the central macula, retinal nerve fiber layer, and ganglion cell-inner plexiform layer (GC-IPL) using spectral domain optical coherence tomography (Cirrus HD-OCT) in eyes with age-related macular degeneration. METHODS: One hundred and thirty-four eyes were included. The measurement repeatability was assessed by an experienced examiner who performed two consecutive measurements using a 512 × 128 macular cube scan and a 200 × 200 optic disk cube scan. To assess changes in macular morphology in patients with age-related macular degeneration, the patients were divided into the following three groups according to the central macular thickness (CMT): A group, CMT < 200 µm; B group, 200 µm ≤ CMT < 300 µm; and C group, CMT > 300 µm. RESULTS: Measurement repeatability was assessed using test-retest variability, a coefficient of variation, and an intraclass correlation coefficient. The mean measurement repeatability for the central macular, retinal nerve fiber layer, and GC-IPL thickness was high in the B group. The mean measurement repeatability for both the central macula and retinal nerve fiber layer thickness was high in the A and C groups, but was lower for the GC-IPL thickness. The measurement repeatability for GC-IPL thickness was high in the B group, but low in the A group and in the C group. CONCLUSION: The automated measurement repeatability for GC-IPL thickness was significantly lower in patients with age-related macular degeneration with out of normal CMT range. The effect of changes in macular morphology should be considered when analyzing GC-IPL thicknesses in a variety of ocular diseases.
Assuntos
Macula Lutea/patologia , Fibras Nervosas/patologia , Disco Óptico/patologia , Células Ganglionares da Retina/patologia , Tomografia de Coerência Óptica/métodos , Acuidade Visual , Degeneração Macular Exsudativa/diagnóstico , Idoso , Progressão da Doença , Feminino , Seguimentos , Humanos , Masculino , Estudos Prospectivos , Fatores de Tempo , Degeneração Macular Exsudativa/fisiopatologiaRESUMO
BACKGROUND: Langerhans cells (LCs) are skin-resident dendritic cells (DCs) that orchestrate skin immunity. CCCTC-binding factor (CTCF) is a highly conserved DNA-binding protein that regulates higher-order chromatin organization and is involved in various gene regulation processes. OBJECTIVE: We sought to clarify a possible role for CTCF in LC homeostasis and function in vivo. METHODS: We used a conditional gene deletion mouse system to generate DC- and LC-specific CTCF-ablated mice. Short hairpin RNA-mediated RNA interference was used to silence CTCF expression in human monocyte-derived Langerhans cells. DC populations were assessed by using flow cytometry and immunofluorescence. Gene expression arrays were performed to identify genes regulated by CTCF in LCs. Contact hypersensitivity and epicutaneous sensitization responses were measured to examine the functional significance of CTCF ablation. RESULTS: DC-specific CTCF deletion led to a reduced pool of systemic DCs, with LCs most severely affected. Decreases in epidermal LC numbers were specifically associated with self-turnover defects. Interestingly, CTCF-deficient LCs demonstrated impaired migration out of the epidermis. Whole-transcriptome analyses revealed that genes that promoted cell adhesion were highly expressed, but CCR7 was downregulated in CTCF-depleted LCs. Hapten-induced contact hypersensitivity responses were more sustained in LC-specific CTCF-deficient mice, whereas epicutaneous sensitization to protein antigen was attenuated, indicating that CTCF-dependent LC homeostasis is required for optimal immune function of LCs in a context-dependent manner. CONCLUSION: Our results show that CTCF positively regulates the homeostatic pool and the efficient emigration of LCs, which are required for modulating the functional immune network of the skin.
Assuntos
Dermatite de Contato/genética , Homeostase/genética , Células de Langerhans/metabolismo , Proteínas Repressoras/genética , Animais , Fator de Ligação a CCCTC , Adesão Celular , Movimento Celular/genética , Movimento Celular/imunologia , Dermatite de Contato/imunologia , Dermatite de Contato/patologia , Epiderme/imunologia , Epiderme/metabolismo , Epiderme/patologia , Perfilação da Expressão Gênica , Regulação da Expressão Gênica , Haptenos , Homeostase/imunologia , Humanos , Células de Langerhans/imunologia , Células de Langerhans/patologia , Camundongos , Camundongos Knockout , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/imunologia , Receptores CCR7/genética , Receptores CCR7/imunologia , Proteínas Repressoras/antagonistas & inibidores , Proteínas Repressoras/deficiência , Proteínas Repressoras/imunologia , Transdução de SinaisRESUMO
The ß-globin locus control region (LCR) is necessary for high-level ß-globin gene transcription and differentiation-dependent relocation of the ß-globin locus from the nuclear periphery to the central nucleoplasm and to foci of hyperphosphorylated Pol II "transcription factories" (TFys). To determine the contribution of individual LCR DNaseI hypersensitive sites (HSs) to transcription and nuclear location, in the present study, we compared ß-globin gene activity and location in erythroid cells derived from mice with deletions of individual HSs, deletions of 2 HSs, and deletion of the whole LCR and found all of the HSs had a similar spectrum of activities, albeit to different degrees. Each HS acts as an independent module to activate expression in an additive manner, and this is correlated with relocation away from the nuclear periphery. In contrast, HSs have redundant activities with respect to association with TFys and the probability that an allele is actively transcribed, as measured by primary RNA transcript FISH. The limiting effect on RNA levels occurs after ß-globin genes associate with TFys, at which time HSs contribute to the amount of RNA arising from each burst of transcription by stimulating transcriptional elongation.
Assuntos
Núcleo Celular/metabolismo , Região de Controle de Locus Gênico/genética , Nucleoplasminas/metabolismo , Transcrição Gênica/fisiologia , Globinas beta/genética , Animais , Células Eritroides/metabolismo , Deleção de Genes , Regulação da Expressão Gênica no Desenvolvimento/fisiologia , Camundongos , Camundongos Transgênicos , RNA Mensageiro/genética , Globinas beta/metabolismoRESUMO
The Ldb1/GATA-1/TAL1/LMO2 complex mediates long-range interaction between the ß-globin locus control region (LCR) and gene in adult mouse erythroid cells, but whether this complex mediates chromatin interactions at other developmental stages or in human cells is unknown. We investigated NLI (Ldb1 homolog) complex occupancy and chromatin conformation of the ß-globin locus in human erythroid cells. In addition to the LCR, we found robust NLI complex occupancy at a site downstream of the (A)γ-globin gene within sequences of BGL3, an intergenic RNA transcript. In cells primarily transcribing ß-globin, BGL3 is not transcribed and BGL3 sequences are occupied by NLI core complex members, together with corepressor ETO2 and by γ-globin repressor BCL11A. The LCR and ß-globin gene establish proximity in these cells. In contrast, when γ-globin transcription is reactivated in these cells, ETO2 participation in the NLI complex at BGL3 is diminished, as is BCL11A occupancy, and both BGL3 and γ-globin are transcribed. In these cells, proximity between the BGL3/γ-globin region and the LCR is established. We conclude that alternative NLI complexes mediate γ-globin transcription or silencing through long-range LCR interactions involving an intergenic site of noncoding RNA transcription and that ETO2 is critical to this process.
Assuntos
Proteínas de Ligação a DNA/genética , Células Eritroides/metabolismo , Proteínas com Domínio LIM/genética , Proteínas Repressoras/genética , Fatores de Transcrição/genética , Proteínas Supressoras de Tumor/genética , gama-Globinas/genética , Regiões 3' não Traduzidas/genética , Proteínas Adaptadoras de Transdução de Sinal/genética , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Adulto , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Proteínas de Ligação a DNA/metabolismo , Células Eritroides/citologia , Fator de Transcrição GATA1/genética , Fator de Transcrição GATA1/metabolismo , Humanos , Células K562 , Proteínas com Domínio LIM/metabolismo , Análise de Sequência com Séries de Oligonucleotídeos , Cultura Primária de Células , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas/metabolismo , RNA não Traduzido/genética , Proteínas Repressoras/metabolismo , Proteína 1 de Leucemia Linfocítica Aguda de Células T , Fatores de Transcrição/metabolismo , Transcrição Gênica/fisiologia , Proteínas Supressoras de Tumor/metabolismo , gama-Globinas/metabolismoRESUMO
The tropomyosin-related kinase (Trk) family of neurotrophin receptors, TrkA, TrkB and TrkC, has been implicated in the growth and survival of human cancers. Here we report that Trks are frequently overexpressed in hepatocellular carcinoma (HCC) from patients and human liver cancer cell lines. To unravel the underlying molecular mechanism(s) for this phenomenon, DNA methylation patterns of CpG islands in TrkA, TrkB, and TrkC genes were examined in normal and cancer cell lines derived from liver. A good correlation was observed between promoter hypermethylation and lower expression of TrkA, TrkB, and TrkC genes, which was supported by the data that inhibiting DNA methylation with 5-azacytidine restored expression of those genes in normal liver cell lines. Furthermore, Trks promoted the proliferation of HepG2 and induced expression of the metastatic regulator, Twist. These results suggest that Trks may contribute to growth and metastasis of liver cancer.
Assuntos
Carcinoma Hepatocelular/genética , Metilação de DNA , Regulação Enzimológica da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Neoplasias Hepáticas/genética , Receptor trkA/genética , Receptor trkB/genética , Receptor trkC/genética , Antimetabólitos Antineoplásicos/farmacologia , Azacitidina/farmacologia , Sequência de Bases , Carcinoma Hepatocelular/patologia , Proliferação de Células , Humanos , Neoplasias Hepáticas/patologia , Dados de Sequência Molecular , Proteínas Nucleares/genética , Regiões Promotoras Genéticas , Receptores de Fator de Crescimento Neural/genética , Proteína 1 Relacionada a Twist/genéticaRESUMO
Transforming growth factor beta 1-induced (TGFBI) protein is an extracellular matrix (ECM) protein that is associated with other ECM proteins and functions as a ligand for various types of integrins. In this study, we investigated how human TGFBI expression is regulated in lung and breast cancer cells. We observed that the TGFBI promoter in A549 and MBA-MD-231 cells, which constitutively express TGFBI, existed in an open chromatin conformation associated with transcriptionally permissive histone modifications. Moreover, we found that TGFBI expression required Sp1 transcription elements that can bind transcription factors Sp1 and Sp3 in vitro. Occupancy of the TGFBI promoter by Sp1 and Sp3 in vivo was only observed in TGFBI-expressing cells, indicating that open chromatin conformation might facilitate the binding of Sp1 and Sp3 to the TGFBI promoter region. TGFBI promoter activity was impaired when Sp1 elements were mutated, but was increased when Sp1 or Sp3 factors was overexpressed. Furthermore, Sp1 inhibition in vivo by mithramycin A, as well as knockdown of Sp1 and/or Sp3 expression by short interfering RNA, significantly reduced TGFBI mRNA and protein levels. Thus, our data demonstrated that the expression of TGFBI is well correlated with chromatin conformation at the TGFBI promoter, and that factors Sp1 and Sp3 are the primary determinants for the control of constitutive expression of TGFBI gene.
Assuntos
Cromatina/metabolismo , Proteínas da Matriz Extracelular/genética , Regulação da Expressão Gênica , Fator de Transcrição Sp1/metabolismo , Fator de Transcrição Sp3/metabolismo , Fator de Crescimento Transformador beta/genética , Linhagem Celular , Linhagem Celular Tumoral , Cromatina/química , Técnicas de Silenciamento de Genes , Histonas/metabolismo , Humanos , Regiões Promotoras Genéticas , Interferência de RNA , RNA Mensageiro/antagonistas & inibidores , RNA Mensageiro/biossíntese , Fator de Transcrição Sp1/genética , Fator de Transcrição Sp3/genéticaRESUMO
A liquid chromatography-tandem mass spectrometric (LC/MS/MS) method was developed for the determination of an atypical antipsychotic drug, lurasidone, in rat plasma. The method involves the addition of acetonitrile and ziprasidone (internal standard) solution to plasma samples, followed by centrifugation. An aliquot of the supernatant was diluted with water and directly injected into the LC/MS/MS system. The separations were performed on a column packed with octadecylsilica (5 µm, 2.0 × 50 mm) with 0.1% formic acid and 0.1% formic acid in acetonitrile as mobile phase and the detection was performed using tandem mass spectrometry by multiple-reaction monitoring via an electrospray ionization source. The standard curve was linear (r = 0.9982) over the concentration range 0.002-1 µg/mL. The intra- and inter-assay precisions were 1.7 and 8.6%, respectively. The accuracy range was from 90.3 to 101.8%. The lower limit of quantification was 2.0 ng/mL using 50 µL of rat plasma sample. The developed analytical method was successfully applied to the pharmacokinetic study of lurasidone in rats.
Assuntos
Antipsicóticos/sangue , Cromatografia Líquida de Alta Pressão/métodos , Isoindóis/sangue , Espectrometria de Massas em Tandem/métodos , Tiazóis/sangue , Acetonitrilas/sangue , Animais , Antipsicóticos/farmacocinética , Isoindóis/farmacocinética , Modelos Lineares , Cloridrato de Lurasidona , Masculino , Piperazinas/sangue , Ratos , Ratos Sprague-Dawley , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Tiazóis/farmacocinéticaRESUMO
BACKGROUND: Laminectomy and laminoplasty are popularly used in posterior cervical spine surgery but still have involved complications. We aimed to compare the clinical outcomes of microscope-assisted extensor muscle-preserving laminectomy (MA-EMPL) and open-door laminoplasty (ODLP) in treating multilevel cervical spondylotic myelopathy (MCSM). METHODS: A prospective study was designed to enroll twenty patients with MCSM underwent MA-EMPL, and recruit twenty-four patients with MCSM received ODLP (control). Radiographic measurements, outcome indicators including Japanese Orthopedic Association (JOA) score and visual analogue score (VAS) were used to evaluate technical effectiveness. Surgical complications were documented to assess technical safety. RESULTS: Postoperative cervical curvature index and range of neck motion (ROM) were not significantly changed except ROM in ODLP group. Postoperative JOA score and VAS in both groups showed improvements at final follow-up. There was no statistical difference in postoperative neurological recovery rates between two groups (67.6%±17.8% vs. 70.15%±19.6%, P=0.632). However, VAS was significantly lower at postoperative 1 month in MA-EMPL group compared with ODLP group (P<0.001). The incidences of C5 palsy were 0 vs. 16.7% between MA-EMPL group and ODLP group. There was no axial symptom occurred in MA-EMPL group while six patients in ODLP group (0 vs. 25%, P=0.049). In addition, the mean blood loss and hospital stay were lesser in MA-EMPL group compared with ODLP group (P<0.001, P=0.002, respectively). CONCLUSIONS: MA-EMPL is an effective, safe and minimally invasive method in treatment of MCSM. Compared with ODLP, MA-EMPL has advantage to decrease intraoperative blood loss, hospital stay, postoperative VAS and axial symptom, as well as preserve postoperative ROM.
RESUMO
The inner ear is a complex sensory organ responsible for hearing and balance. Formation of the inner ear is dependent on tight regulation of spatial and temporal expression of genes that direct a series of developmental processes. Recently, epigenetic regulation has emerged as a crucial regulator of the development of various organs. However, what roles higher-order chromatin organization and its regulator molecules play in inner ear development are unclear. CCCTC-binding factor (CTCF) is a highly conserved 11-zinc finger protein that regulates the three-dimensional architecture of chromatin, and is involved in various gene regulation processes. To delineate the role of CTCF in inner ear development, the present study investigated inner ear-specific Ctcf knockout mouse embryos (Pax2-Cre; Ctcffl/fl ). The loss of Ctcf resulted in multiple defects of inner ear development and severely compromised otic neurogenesis, which was partly due to a loss of Neurog1 expression. Furthermore, reduced Neurog1 gene expression by CTCF knockdown was found to be associated with changes in histone modification at the gene's promoter, as well as its upstream enhancer. The results of the present study demonstrate that CTCF plays an essential role in otic neurogenesis by modulating histone modification in the Neurog1 locus.
Assuntos
Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Fator de Ligação a CCCTC/metabolismo , Orelha Interna/inervação , Loci Gênicos , Histonas/metabolismo , Proteínas do Tecido Nervoso/genética , Neurogênese , Processamento de Proteína Pós-Traducional , Acetilação , Animais , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Diferenciação Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Orelha Interna/embriologia , Orelha Interna/patologia , Embrião de Mamíferos/metabolismo , Deleção de Genes , Regulação da Expressão Gênica no Desenvolvimento/efeitos dos fármacos , Técnicas de Silenciamento de Genes , Lisina/metabolismo , Camundongos , Proteínas do Tecido Nervoso/metabolismo , Neurogênese/efeitos dos fármacos , Neurogênese/genética , Processamento de Proteína Pós-Traducional/efeitos dos fármacos , Gânglio Espiral da Cóclea/efeitos dos fármacos , Gânglio Espiral da Cóclea/metabolismo , Tretinoína/farmacologiaRESUMO
Lineage-specific transcription factors are critical for long-range enhancer interactions, but direct or indirect contributions of architectural proteins such as CCCTC-binding factor (CTCF) to enhancer function remain less clear. The LDB1 complex mediates enhancer-gene interactions at the ß-globin locus through LDB1 self-interaction. We find that an LDB1-bound enhancer upstream of carbonic anhydrase 2 (Car2) activates its expression by interacting directly with CTCF at the gene promoter. Both LDB1 and CTCF are required for enhancer-Car2 looping, and the domain of LDB1 contacted by CTCF is necessary to rescue Car2 transcription in LDB1-deficient cells. Genome-wide studies and CRISPR/Cas9 genome editing indicate that LDB1-CTCF enhancer looping underlies activation of a substantial fraction of erythroid genes. Our results provide a mechanism by which long-range interactions of architectural protein CTCF can be tailored to achieve a tissue-restricted pattern of chromatin loops and gene expression.
Assuntos
Fator de Ligação a CCCTC/metabolismo , Proteínas de Ligação a DNA/fisiologia , Elementos Facilitadores Genéticos , Células Eritroides/metabolismo , Proteínas com Domínio LIM/fisiologia , Animais , Linhagem da Célula , Expressão Gênica , Regulação da Expressão Gênica , Células HEK293 , Humanos , Camundongos , Ligação Proteica , Domínios e Motivos de Interação entre ProteínasRESUMO
Special AT-rich sequence binding protein 1 (SATB1) is a nuclear matrix-associated DNA-binding protein that functions as a chromatin organizer. SATB1 is highly expressed in aggressive breast cancer cells and promotes growth and metastasis by reprograming gene expression. Through genomewide cross-examination of gene expression and histone methylation, we identified SATB1 target genes for which expression is associated with altered epigenetic marks. Among the identified genes, long noncoding RNA urothelial carcinoma-associated 1 (UCA1) was upregulated by SATB1 depletion. Upregulation of UCA1 coincided with increased H3K4 trimethylation (H3K4me3) levels and decreased H3K27 trimethylation (H3K27me3) levels. Our study showed that SATB1 binds to the upstream region of UCA1 in vivo, and that its promoter activity increases with SATB1 depletion. Furthermore, simultaneous depletion of SATB1 and UCA1 potentiated suppression of tumor growth and cell survival. Thus, SATB1 repressed the expression of oncogenic UCA1, suppressing growth and survival of breast cancer cells. [BMB Reports 2016; 49(10): 578-583].
Assuntos
Epigênese Genética , Proteínas de Ligação à Região de Interação com a Matriz/metabolismo , RNA Longo não Codificante/metabolismo , Western Blotting , Neoplasias da Mama/genética , Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Linhagem Celular Tumoral , Imunoprecipitação da Cromatina , Feminino , Citometria de Fluxo , Genes Reporter , Histonas/metabolismo , Humanos , Proteínas de Ligação à Região de Interação com a Matriz/antagonistas & inibidores , Proteínas de Ligação à Região de Interação com a Matriz/genética , Metilação , Interferência de RNA , RNA Mensageiro/metabolismo , RNA Interferente Pequeno/metabolismo , Reação em Cadeia da Polimerase em Tempo Real , Análise de Sequência de RNA , Regulação para CimaRESUMO
Fibrous dysplasia of the spine is very rarely observed. We reported a case of a 57-year-old woman, who presented with neck and bilateral shoulder pain with histologically confirmed fibrous dysplasia, involving the first and second thoracic vertebrae. Clinical and radiological findings were not specific for fibrous dysplasia. The histological biopsy was required for a confirmed diagnosis. Endocrine and metabolic evaluations are required to rule out diseases such as hyperthyroidism, Cushing syndrome and osteomalacia. Fibrous dyplasia can be managed by appropriate medical and surgical treatments based on the patient's neurological status and symptoms. Our patient was given intravenous pamidronate 60mg/day for 3 days. After 9 months, her initial symptoms were improved, but computed tomography scan of the thoracic spine showed no change of the lesions.
RESUMO
Trichomoniasis caused by the parasitic protozoan Trichomonas vaginalis is the most common sexually transmitted disease in the world. Dendritic cells are antigen presenting cells that initiate immune responses by directing the activation and differentiation of naïve T cells. In this study, we analyzed the effect of Trichomonas vaginalis-derived Secretory Products on the differentiation and function of dendritic cells. Differentiation of bone marrow-derived dendritic cells in the presence of T. vaginalis-derived Secretory Products resulted in inhibition of lipopolysaccharide-induced maturation of dendritic cells, down-regulation of IL-12, and up-regulation of IL-10. The protein components of T. vaginalis-derived Secretory Products were shown to be responsible for altered function of bone marrow- derived dendritic cells. Chromatin immunoprecipitation assay demonstrated that IL-12 expression was regulated at the chromatin level in T. vaginalis-derived Secretory Productstreated dendritic cells. Our results demonstrated that T. vaginalis- derived Secretory Products modulate the maturation and cytokine production of dendritic cells leading to immune tolerance.
Assuntos
Células Dendríticas/citologia , Trichomonas vaginalis/metabolismo , Animais , Antígenos de Protozoários/imunologia , Antígenos de Protozoários/metabolismo , Antígenos de Protozoários/farmacologia , Células da Medula Óssea/citologia , Diferenciação Celular , Imunoprecipitação da Cromatina , Células Dendríticas/efeitos dos fármacos , Células Dendríticas/metabolismo , Regulação para Baixo/efeitos dos fármacos , Endopeptidase K/metabolismo , Feminino , Fator Estimulador de Colônias de Granulócitos e Macrófagos/farmacologia , Interleucina-10 , Interleucina-12 , Lipopolissacarídeos/toxicidade , Camundongos , Camundongos Endogâmicos C57BL , Regulação para Cima/efeitos dos fármacosRESUMO
ABCG2 is a member of the ATP binding cassette (ABC) transmembrane proteins that plays an important role in stem cell biology and drug resistance of cancer cells. In this study, we investigated how expression of human ABCG2 gene is regulated in lung cancer A549 cells. Binding of Sp1 and Sp3 transcription factors to the ABCG2 promoter in vitro and in vivo was elucidated by electrophoretic mobility shift assay and chromatin immunoprecipitation assay. The ABCG2 promoter activity was impaired when Sp1 sites were mutated but was enhanced by overexpression of Sp1 or Sp3 proteins. Knockdown of Sp1 or Sp3 expression by short interfering RNA significantly decreased the expression of ABCG2 mRNA and protein, resulting in attenuated formation of the side population in A549 cells. In addition, Sp1 inhibition in vivo by mithramycin A suppressed the percentage of the side population fraction and sphere forming activities of A549 cells. Moreover, inhibiting Sp1- or Sp3-dependent ABCG2 expression caused chemosensitization to the anticancer drug cisplatin. Collectively, our results demonstrate that Sp1 and Sp3 transcription factors are the primary determinants for activating basal transcription of the ABCG2 gene and play an important role in maintaining the side population phenotype of lung cancer cells.
Assuntos
Transportadores de Cassetes de Ligação de ATP/genética , Transportadores de Cassetes de Ligação de ATP/metabolismo , Resistencia a Medicamentos Antineoplásicos/genética , Neoplasias Pulmonares/genética , Proteínas de Neoplasias/genética , Proteínas de Neoplasias/metabolismo , Fator de Transcrição Sp1/metabolismo , Fator de Transcrição Sp3/metabolismo , Membro 2 da Subfamília G de Transportadores de Cassetes de Ligação de ATP , Sítios de Ligação , Linhagem Celular , Cisplatino/farmacologia , Ensaio de Desvio de Mobilidade Eletroforética , Regulação Neoplásica da Expressão Gênica , Técnicas de Silenciamento de Genes , Humanos , Neoplasias Pulmonares/patologia , Plicamicina/análogos & derivados , Plicamicina/farmacologia , Regiões Promotoras Genéticas , Células da Side Population/fisiologia , Fator de Transcrição Sp1/antagonistas & inibidores , Fator de Transcrição Sp1/genética , Fator de Transcrição Sp3/genéticaRESUMO
CONCLUSION: The oncological and functional outcomes of hypopharyngeal cancer after conservative laryngeal surgery are fairly acceptable, making this a reasonable initial treatment option for selected patients. OBJECTIVE: The purpose of this study was to assess the clinical outcomes of patients with hypopharyngeal squamous cell carcinoma (SCC) treated with conservative laryngeal surgery with partial pharyngectomy. METHODS: Fifty-eight patients with hypopharyngeal SCC who underwent laryngeal preservation surgery were enrolled. The tumors were classified as cT1 in 5 (8.6%) patients, cT2 in 35 (60.3%), cT3 in 14 (24.1%), and cT4a in 4 (6.9%) patients. RESULTS: Surgical outcomes: 5-year overall and disease-specific survival rates were 78% and 77.6%. Recurrent disease developed in 13 patients (22.4%). Multivariate analysis revealed that level VI metastasis confirmed by histopathological analysis, close (< 5 mm) histologic margin, advanced N stage, and posterior pharyngeal wall tumor were independent factors associated with poor disease-specific survival. Functional outcomes: 50 patients (86.2%) could obtain all their nutritional needs orally. Eight patients needed the assistance of a percutaneous endoscopic gastrostomy tube. Oral re-alimentation was achieved within a mean of 26.1 days after surgery. Fifty-one patients (87.9%) could be decannulated after a mean of 43.8 days postoperatively.
Assuntos
Carcinoma de Células Escamosas/cirurgia , Neoplasias Hipofaríngeas/cirurgia , Faringectomia , Adulto , Idoso , Carcinoma de Células Escamosas/patologia , Feminino , Humanos , Neoplasias Hipofaríngeas/patologia , Metástase Linfática , Masculino , Pessoa de Meia-Idade , Faringe/patologia , Estudos Retrospectivos , Resultado do TratamentoRESUMO
IL-31, a newly identified member of the IL-6 cytokine family, is involved in many pathological conditions, including atopic dermatitis and pruritis. In this study, we investigated how expression of IL-31 is regulated in T cells and mast cells. We observed that expression of IL-31 required a calcium signal and was dependent on the calcineurin-NFAT signaling pathway. Moreover, we found that IL-31 promoter contains a positive regulatory region that mediates calcium- and IL-4-dependent induction of the IL-31 gene and demonstrated that a change into an open chromatin conformation occurs in this region after stimulation with calcium and IL-4. Whereas IL-4 responsiveness required STAT6 binding sites, calcium responsiveness of IL-31 promoter required NFAT binding sites that bind NFATc1 and NFATc2 in vitro and in vivo. The induction of IL-31 promoter activity was impaired when these sites were mutated but was enhanced by CA-NFATc1 or STAT6 proteins and further increased synergistically by combinations of both proteins. Furthermore, the importance of STAT6 proteins was indicated by impaired, IL-4-mediated induction of IL-31 in STAT6-diminished Jurkat cells. Thus, our data demonstrate that calcium and IL-4 signals are required to mediate induction of IL-31 in Th2 cells and mast cells and that this induction appears to result from specific binding of NFAT and STAT6 proteins.