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1.
Nat Commun ; 12(1): 5242, 2021 09 02.
Artigo em Inglês | MEDLINE | ID: mdl-34475398

RESUMO

Genome-wide association studies (GWAS) have linked single nucleotide polymorphisms (SNPs) at >250 loci in the human genome to type 2 diabetes (T2D) risk. For each locus, identifying the functional variant(s) among multiple SNPs in high linkage disequilibrium is critical to understand molecular mechanisms underlying T2D genetic risk. Using massively parallel reporter assays (MPRA), we test the cis-regulatory effects of SNPs associated with T2D and altered in vivo islet chromatin accessibility in MIN6 ß cells under steady state and pathophysiologic endoplasmic reticulum (ER) stress conditions. We identify 1,982/6,621 (29.9%) SNP-containing elements that activate transcription in MIN6 and 879 SNP alleles that modulate MPRA activity. Multiple T2D-associated SNPs alter the activity of short interspersed nuclear element (SINE)-containing elements that are strongly induced by ER stress. We identify 220 functional variants at 104 T2D association signals, narrowing 54 signals to a single candidate SNP. Together, this study identifies elements driving ß cell steady state and ER stress-responsive transcriptional activation, nominates causal T2D SNPs, and uncovers potential roles for repetitive elements in ß cell transcriptional stress response and T2D genetics.


Assuntos
Diabetes Mellitus Tipo 2/genética , Estresse do Retículo Endoplasmático/genética , Células Secretoras de Insulina/patologia , Polimorfismo de Nucleotídeo Único , Ativação Transcricional/genética , Alelos , Animais , Linhagem Celular , Cromatina/metabolismo , Diabetes Mellitus Tipo 2/patologia , Estudo de Associação Genômica Ampla , Humanos , Camundongos , Locos de Características Quantitativas , Elementos Nucleotídeos Curtos e Dispersos/genética
2.
Mol Cell ; 81(16): 3368-3385.e9, 2021 08 19.
Artigo em Inglês | MEDLINE | ID: mdl-34375583

RESUMO

The mechanistic understanding of nascent RNAs in transcriptional control remains limited. Here, by a high sensitivity method methylation-inscribed nascent transcripts sequencing (MINT-seq), we characterized the landscapes of N6-methyladenosine (m6A) on nascent RNAs. We uncover heavy but selective m6A deposition on nascent RNAs produced by transcription regulatory elements, including promoter upstream antisense RNAs and enhancer RNAs (eRNAs), which positively correlates with their length, inclusion of m6A motif, and RNA abundances. m6A-eRNAs mark highly active enhancers, where they recruit nuclear m6A reader YTHDC1 to phase separate into liquid-like condensates, in a manner dependent on its C terminus intrinsically disordered region and arginine residues. The m6A-eRNA/YTHDC1 condensate co-mixes with and facilitates the formation of BRD4 coactivator condensate. Consequently, YTHDC1 depletion diminished BRD4 condensate and its recruitment to enhancers, resulting in inhibited enhancer and gene activation. We propose that chemical modifications of eRNAs together with reader proteins play broad roles in enhancer activation and gene transcriptional control.


Assuntos
Adenosina/análogos & derivados , Proteínas de Ciclo Celular/genética , Proteínas do Tecido Nervoso/genética , Fatores de Processamento de RNA/genética , RNA/genética , Fatores de Transcrição/genética , Adenosina/genética , Elementos Facilitadores Genéticos/genética , Regulação da Expressão Gênica/genética , Humanos , Metilação , Elementos Reguladores de Transcrição/genética , Ativação Transcricional/genética
3.
Methods Mol Biol ; 2351: 201-210, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34382191

RESUMO

Regulation of gene expression is a key feature for higher eukaryotes and how chromatin topology relates to gene activation is an intense area of research. Enhancer-promoter interactions are believed to mediate activation of target genes. Bidirectional transcription represents one hallmark of active enhancers that can be measured using transcriptome technologies such as Cap analysis of gene expression (CAGE). Recently, we have developed RNA and DNA interacting complexes ligated and sequenced (RADICL-Seq) a novel methodology to map genome-wide RNA-chromatin interactions in intact nuclei. Here, we describe how CAGE and RADICL-Seq data can be used to characterize enhancer elements and identify their target genes.


Assuntos
Biologia Computacional/métodos , Elementos Facilitadores Genéticos , Regulação da Expressão Gênica , Regiões Promotoras Genéticas , Capuzes de RNA , Algoritmos , Cromatina/genética , Bases de Dados Genéticas , Sequenciamento de Nucleotídeos em Larga Escala , Sítio de Iniciação de Transcrição , Transcrição Genética , Ativação Transcricional , Transcriptoma
4.
Int J Mol Sci ; 22(16)2021 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-34445672

RESUMO

In mammalian cells, two cellular organelles, mitochondria and peroxisomes, share the ability to degrade fatty acid chains. Although each organelle harbors its own fatty acid ß-oxidation pathway, a distinct mitochondrial system feeds the oxidative phosphorylation pathway for ATP synthesis. At the same time, the peroxisomal ß-oxidation pathway participates in cellular thermogenesis. A scientific milestone in 1965 helped discover the hepatomegaly effect in rat liver by clofibrate, subsequently identified as a peroxisome proliferator in rodents and an activator of the peroxisomal fatty acid ß-oxidation pathway. These peroxisome proliferators were later identified as activating ligands of Peroxisome Proliferator-Activated Receptor α (PPARα), cloned in 1990. The ligand-activated heterodimer PPARα/RXRα recognizes a DNA sequence, called PPRE (Peroxisome Proliferator Response Element), corresponding to two half-consensus hexanucleotide motifs, AGGTCA, separated by one nucleotide. Accordingly, the assembled complex containing PPRE/PPARα/RXRα/ligands/Coregulators controls the expression of the genes involved in liver peroxisomal fatty acid ß-oxidation. This review mobilizes a considerable number of findings that discuss miscellaneous axes, covering the detailed expression pattern of PPARα in species and tissues, the lessons from several PPARα KO mouse models and the modulation of PPARα function by dietary micronutrients.


Assuntos
Ácidos Graxos/metabolismo , PPAR alfa/metabolismo , Peroxissomos/metabolismo , Acil-CoA Oxidase/metabolismo , Animais , Humanos , Fígado/metabolismo , Oxirredução , Oxirredutases/metabolismo , PPAR alfa/fisiologia , Proliferadores de Peroxissomos , Receptores Citoplasmáticos e Nucleares/metabolismo , Receptores do Ácido Retinoico/metabolismo , Elementos de Resposta/genética , Receptores X de Retinoides/metabolismo , Ativação Transcricional/genética
5.
FASEB J ; 35(9): e21814, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34369624

RESUMO

Alteration in glucose homeostasis during cancer metabolism is an important phenomenon. Though several important transcription factors have been well studied in the context of the regulation of metabolic gene expression, the role of epigenetic readers in this regard remains still elusive. Epigenetic reader protein transcription factor 19 (TCF19) has been recently identified as a novel glucose and insulin-responsive factor that modulates histone posttranslational modifications to regulate glucose homeostasis in hepatocytes. Here we report that TCF19 interacts with a non-histone, well-known tumor suppressor protein 53 (p53) and co-regulates a wide array of metabolic genes. Among these, the p53-responsive carbohydrate metabolic genes Tp53-induced glycolysis and apoptosis regulator (TIGAR) and Cytochrome C Oxidase assembly protein 2 (SCO2), which are the key regulators of glycolysis and oxidative phosphorylation respectively, are under direct regulation of TCF19. Remarkably, TCF19 can form different transcription activation/repression complexes which show substantial overlap with that of p53, depending on glucose-mediated variant stress situations as obtained from IP/MS studies. Interestingly, we observed that TCF19/p53 complexes either have CBP or HDAC1 to epigenetically program the expression of TIGAR and SCO2 genes depending on short-term high glucose or prolonged high glucose conditions. TCF19 or p53 knockdown significantly altered the cellular lactate production and led to increased extracellular acidification rate. Similarly, OCR and cellular ATP production were reduced and mitochondrial membrane potential was compromised upon depletion of TCF19 or p53. Subsequently, through RNA-Seq analysis from patients with hepatocellular carcinoma, we observed that TCF19/p53-mediated metabolic regulation is fundamental for sustenance of cancer cells. Together the study proposes that TCF19/p53 complexes can regulate metabolic gene expression programs responsible for mitochondrial energy homeostasis and stress adaptation.


Assuntos
Proteínas Reguladoras de Apoptose/genética , Carcinoma Hepatocelular/genética , Neoplasias Hepáticas/genética , Mitocôndrias/genética , Chaperonas Moleculares/genética , Monoéster Fosfórico Hidrolases/genética , Fatores de Transcrição/genética , Transcrição Genética/genética , Proteína Supressora de Tumor p53/genética , Adaptação Biológica/genética , Apoptose/genética , Linhagem Celular Tumoral , Metabolismo Energético/genética , Glucose/genética , Células Hep G2 , Homeostase/genética , Humanos , Potencial da Membrana Mitocondrial/genética , Estresse Fisiológico/genética , Ativação Transcricional/genética
6.
FASEB J ; 35(9): e21827, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34383980

RESUMO

Neuron-derived orphan receptor 1, NR4A3 (Nor1)/NR4A3 is an orphan nuclear receptor involved in the transcriptional control of developmental and neurological functions. Oxidative stress-induced conditions are primarily associated with neurological defects in humans, yet the impact on Nor1-mediated transcription of neuronal genes remains with unknown mechanism. Here, we demonstrate that Nor1 is a non-conventional target of SUMO2/3 conjugation at Lys-137 contained in an atypic ψKxSP motif referred to as the pSuM. Nor1 pSuM SUMOylation differs from the canonical process with the obligate phosphorylation of Ser-139 by Ras signaling to create the required negatively charged interface for SUMOylation. Additional phosphorylation at sites flanking the pSuM is also mediated by the coordinated action of protein kinase casein kinase 2 to function as a small ubiquitin-like modifier enhancer, regulating Nor1-mediated transcription and proteasomal degradation. Nor1 responsive genes involved in cell proliferation and metabolism, such as activating transcription factor 3, cyclin D1, CASP8 and FADD-like apoptosis regulator, and enolase 3 were upregulated in response to pSuM disruption in mouse HT-22 hippocampal neuronal cells and human neuroblastoma SH-SY5Y cells. We also identified critical antioxidant genes, such as catalase, superoxide dismutase 1, and microsomal glutathione S-transferase 2, as responsive targets of Nor1 under pSuM regulation. Nor1 SUMOylation impaired gene transcription through less effective Nor1 chromatin binding and reduced enrichment of histone H3K27ac marks to gene promoters. These effects resulted in decreased neuronal cell growth, increased apoptosis, and reduced survival to oxidative stress damage, underlying the role of pSuM-modified Nor1 in redox homeostasis. Our findings uncover a hierarchical post-translational mechanism that dictates Nor1 non-canonical SUMOylation, disrupting Nor1 transcriptional competence, and neuroprotective redox sensitivity.


Assuntos
Sobrevivência Celular/genética , Proteínas de Ligação a DNA/genética , Receptores de Esteroides/genética , Receptores dos Hormônios Tireóideos/genética , Sumoilação/genética , Animais , Apoptose/genética , Linhagem Celular , Linhagem Celular Tumoral , Proliferação de Células/genética , Quinase do Ponto de Checagem 2/genética , Regulação da Expressão Gênica/genética , Células HEK293 , Hipocampo/metabolismo , Homeostase/genética , Humanos , Camundongos , Neuroblastoma/genética , Neurônios/metabolismo , Oxirredução , Estresse Oxidativo/genética , Fosforilação/genética , Regiões Promotoras Genéticas/genética , Processamento de Proteína Pós-Traducional/genética , Transcrição Genética/genética , Ativação Transcricional/genética , Regulação para Cima/genética
7.
Orphanet J Rare Dis ; 16(1): 334, 2021 07 31.
Artigo em Inglês | MEDLINE | ID: mdl-34332615

RESUMO

BACKGROUND: TBX1 (T-box transcription factor 1) is a major candidate gene that likely contributes to the etiology of velo-cardio-facial syndrome/DiGeorge syndrome (VCFS/DGS). Although the haploinsufficiency of TBX1 in both mice and humans results in congenital cardiac malformations, little has been elucidated about its upstream regulation. We aimed to explore the transcriptional regulation and dysregulation of TBX1. METHODS: Different TBX1 promoter reporters were constructed. Luciferase assays and electrophoretic mobility shift assays (EMSAs) were used to identify a cis-regulatory element within the TBX1 promoter region and its trans-acting factor. The expression of proteins was identified by immunohistochemistry and immunofluorescence. Variants in the cis-regulatory element were screened in conotruncal defect (CTD) patients. In vitro functional assays were performed to show the effects of the variants found in CTD patients on the transactivation of TBX1. RESULTS: We identified a cis-regulatory element within intron 1 of TBX1 that was found to be responsive to GATA6 (GATA binding protein 6), a transcription factor crucial for cardiogenesis. The expression patterns of GATA6 and TBX1 overlapped in the pharyngeal arches of human embryos. Transfection experiments and EMSA indicated that GATA6 could activate the transcription of TBX1 by directly binding with its GATA cis-regulatory element in vitro. Furthermore, sequencing analyses of 195 sporadic CTD patients without the 22q11.2 deletion or duplication identified 3 variants (NC_000022.11:g.19756832C > G, NC_000022.11:g.19756845C > T, and NC_000022.11:g. 19756902G > T) in the non-coding cis-regulatory element of TBX1. Luciferase assays showed that all 3 variants led to reduced transcription of TBX1 when incubated with GATA6. CONCLUSIONS: Our findings showed that TBX1 might be a direct transcriptional target of GATA6, and variants in the non-coding cis-regulatory element of TBX1 disrupted GATA6-mediated transactivation.


Assuntos
Síndrome de DiGeorge , Cardiopatias Congênitas , Animais , Síndrome de DiGeorge/genética , Fator de Transcrição GATA6 , Humanos , Camundongos , Proteínas com Domínio T/genética , Proteínas com Domínio T/metabolismo , Fatores de Transcrição/genética , Ativação Transcricional/genética
8.
J Transl Med ; 19(1): 342, 2021 08 09.
Artigo em Inglês | MEDLINE | ID: mdl-34372882

RESUMO

BACKGROUND: We tried to elaborate the molecular mechanism of ETS-like transcription factor 4 (ELK4) affecting gastric cancer (GC) progression through M2 polarization of macrophages mediated by lysine-specific demethylase 5A (KDM5A)-Praja2 (PJA2)-kinase suppressor of ras 1 (KSR1) axis. METHODS: GC expression dataset was obtained from GEO database, and the downstream regulatory mechanism of ELK4 was predicted. Tumor-associated macrophages (TAMs) were isolated from GC tissues. The interaction among ELK4, KDM5A, PJA2 and KSR1 was analyzed by dual luciferase reporter gene, ChIP and Co-IP assays. The stability of KSR1 protein was detected by cycloheximide (CHX) treatment. After TAMs were co-cultured with HGC-27 cells, HGC-27 cell biological processes were assessed through gain- and loss-of function assays. Tumorigenicity was detected by tumorigenicity test in nude mice. RESULTS: In GC and TAMs, ELK4, KDM5A and KSR1 were highly expressed, while PJA2 was lowly expressed. M2 polarization of macrophages promoted the development of GC. ELK4 activated KDM5A by transcription and promoted macrophage M2 polarization. KDM5A inhibited the expression of PJA2 by removing H3K4me3 of PJA2 promoter, which promoted M2 polarization of macrophages. PJA2 reduced KSR1 by ubiquitination. ELK4 promoted the proliferative, migrative and invasive potentials of GC cells as well as the growth of GC xenografts by regulating KSR1. CONCLUSION: ELK4 may reduce the PJA2-dependent inhibition of KSR1 by transcriptional activation of KDM5A to promote M2 polarization of macrophages, thus promoting the development of GC.


Assuntos
Neoplasias Gástricas , Animais , Linhagem Celular Tumoral , Humanos , Ativação de Macrófagos , Macrófagos , Camundongos , Camundongos Nus , Proteína 2 de Ligação ao Retinoblastoma , Neoplasias Gástricas/genética , Ativação Transcricional , Ubiquitina-Proteína Ligases , Proteínas Elk-4 do Domínio ets
9.
Methods Mol Biol ; 2351: 307-320, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34382197

RESUMO

The transition from silenced heterochromatin to a biologically active state and vice versa is a fundamental part of the implementation of cell type-specific gene expression programs. To reveal structure-function relationships and dissect the underlying mechanisms, experiments that ectopically induce transcription are highly informative. In particular, the approach to perturb chromatin states by recruiting fusions of the catalytically inactive dCas9 protein in a sequence-specific manner to a locus of interest has been used in numerous applications. Here, we describe how this approach can be applied to activate pericentric heterochromatin (PCH) in mouse cells as a prototypic silenced state by providing protocols for the following workflow: (a) Recruitment of dCas9 fusion constructs with the strong transcriptional activator VPR to PCH. (b) Analysis of the resulting changes in chromatin compaction, epigenetic marks, and active transcription by fluorescence microscopy-based readouts. (c) Automated analysis of the resulting images with a set of scripts in the R programming language. Furthermore, we discuss how parameters for chromatin decondensation and active transcription are extracted from these experiments and can be combined with other readouts to gain insights into PCH activation.


Assuntos
Proteína 9 Associada à CRISPR/metabolismo , Regulação da Expressão Gênica , Heterocromatina/genética , Ativação Transcricional , Animais , Proteína 9 Associada à CRISPR/genética , Cromatina/genética , Cromatina/metabolismo , Fibroblastos/metabolismo , Imunofluorescência/métodos , Expressão Gênica , Heterocromatina/metabolismo , Processamento de Imagem Assistida por Computador , Camundongos , Microscopia de Fluorescência , Ligação Proteica , Transfecção , Fluxo de Trabalho
10.
Nat Commun ; 12(1): 4853, 2021 08 11.
Artigo em Inglês | MEDLINE | ID: mdl-34381046

RESUMO

SMAD4 is mutated in human lung cancer, but the underlying mechanism by which Smad4 loss-of-function (LOF) accelerates lung cancer metastasis is yet to be elucidated. Here, we generate a highly aggressive lung cancer mouse model bearing conditional KrasG12D, p53fl/fl LOF and Smad4fl/fl LOF mutations (SPK), showing a much higher incidence of tumor metastases than the KrasG12D, p53fl/fl (PK) mice. Molecularly, PAK3 is identified as a downstream effector of Smad4, mediating metastatic signal transduction via the PAK3-JNK-Jun pathway. Upregulation of PAK3 by Smad4 LOF in SPK mice is achieved by attenuating Smad4-dependent transcription of miR-495 and miR-543. These microRNAs (miRNAs) directly bind to the PAK3 3'UTR for blockade of PAK3 production, ultimately regulating lung cancer metastasis. An inverse correlation between Smad4 and PAK3 pathway components is observed in human lung cancer. Our study highlights the Smad4-PAK3 regulation as a point of potential therapy in metastatic lung cancer.


Assuntos
Neoplasias Pulmonares/patologia , MicroRNAs/genética , Proteína Smad4/metabolismo , Quinases Ativadas por p21/metabolismo , Regiões 3' não Traduzidas , Animais , Movimento Celular , Regulação Neoplásica da Expressão Gênica , Humanos , Proteínas Quinases JNK Ativadas por Mitógeno/metabolismo , Mutação com Perda de Função , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/metabolismo , Camundongos , MicroRNAs/metabolismo , Metástase Neoplásica , Proteínas Proto-Oncogênicas c-jun/metabolismo , Transdução de Sinais , Proteína Smad4/genética , Ativação Transcricional , Quinases Ativadas por p21/genética
11.
Nat Commun ; 12(1): 5066, 2021 08 20.
Artigo em Inglês | MEDLINE | ID: mdl-34417456

RESUMO

Prostate cancer (PCa) shows strong dependence on the androgen receptor (AR) pathway. Here, we show that squalene epoxidase (SQLE), an enzyme of the cholesterol biosynthesis pathway, is overexpressed in advanced PCa and its expression correlates with poor survival. SQLE expression is controlled by micro-RNA 205 (miR-205), which is significantly downregulated in advanced PCa. Restoration of miR-205 expression or competitive inhibition of SQLE led to inhibition of de novo cholesterol biosynthesis. Furthermore, SQLE was essential for proliferation of AR-positive PCa cell lines, including abiraterone or enzalutamide resistant derivatives, and blocked transactivation of the AR pathway. Inhibition of SQLE with the FDA approved antifungal drug terbinafine also efficiently blocked orthotopic tumour growth in mice. Finally, terbinafine reduced levels of prostate specific antigen (PSA) in three out of four late-stage PCa patients. These results highlight SQLE as a therapeutic target for the treatment of advanced PCa.


Assuntos
Colesterol/biossíntese , Regulação para Baixo/genética , Regulação Neoplásica da Expressão Gênica , MicroRNAs/metabolismo , Neoplasias da Próstata/tratamento farmacológico , Neoplasias da Próstata/genética , Esqualeno Mono-Oxigenase/antagonistas & inibidores , Idoso , Idoso de 80 Anos ou mais , Animais , Sequência de Bases , Linhagem Celular Tumoral , Proliferação de Células/genética , Sobrevivência Celular , Estudos de Coortes , Simulação por Computador , Modelos Animais de Doenças , Resistencia a Medicamentos Antineoplásicos/genética , Humanos , Masculino , Camundongos , Camundongos SCID , MicroRNAs/genética , Pessoa de Meia-Idade , Invasividade Neoplásica , Metástase Neoplásica , Estadiamento de Neoplasias , Antígeno Prostático Específico/metabolismo , Neoplasias da Próstata/patologia , Neoplasias de Próstata Resistentes à Castração/genética , Neoplasias de Próstata Resistentes à Castração/patologia , Receptores Androgênicos/metabolismo , Esqualeno Mono-Oxigenase/genética , Esqualeno Mono-Oxigenase/metabolismo , Terbinafina/farmacologia , Ativação Transcricional/genética
12.
Nat Immunol ; 22(9): 1093-1106, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34282331

RESUMO

Neutrophils display distinct gene expression patters depending on their developmental stage, activation state and tissue microenvironment. To determine the transcription factor networks that shape these responses in a mouse model, we integrated transcriptional and chromatin analyses of neutrophils during acute inflammation. We showed active chromatin remodeling at two transition stages: bone marrow-to-blood and blood-to-tissue. Analysis of differentially accessible regions revealed distinct sets of putative transcription factors associated with control of neutrophil inflammatory responses. Using ex vivo and in vivo approaches, we confirmed that RUNX1 and KLF6 modulate neutrophil maturation, whereas RELB, IRF5 and JUNB drive neutrophil effector responses and RFX2 and RELB promote survival. Interfering with neutrophil activation by targeting one of these factors, JUNB, reduced pathological inflammation in a mouse model of myocardial infarction. Therefore, our study represents a blueprint for transcriptional control of neutrophil responses in acute inflammation and opens possibilities for stage-specific therapeutic modulation of neutrophil function in disease.


Assuntos
Montagem e Desmontagem da Cromatina/genética , Inflamação/imunologia , Neutrófilos/imunologia , Ativação Transcricional/genética , Animais , Células CHO , Linhagem Celular , Subunidade alfa 2 de Fator de Ligação ao Core/metabolismo , Cricetulus , Feminino , Fatores Reguladores de Interferon/metabolismo , Fator 6 Semelhante a Kruppel/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Infarto do Miocárdio/imunologia , Infarto do Miocárdio/patologia , Fatores de Transcrição de Fator Regulador X/metabolismo , Fator de Transcrição RelB/metabolismo , Fatores de Transcrição/metabolismo , Transcrição Genética/genética
13.
Int J Mol Sci ; 22(13)2021 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-34281250

RESUMO

Amelogenin comprises ~90% of enamel proteins; however, the involvement of Amelx transcriptional activation in regulating ameloblast differentiation from induced pluripotent stem cells (iPSCs) remains unknown. In this study, we generated doxycycline-inducible Amelx-expressing mouse iPSCs (Amelx-iPSCs). We then established a three-stage ameloblast induction strategy from Amelx-iPSCs, including induction of surface ectoderm (stage 1), dental epithelial cells (DECs; stage 2), and ameloblast lineage (stage 3) in sequence, by manipulating several signaling molecules. We found that adjunctive use of lithium chloride (LiCl) in addition to bone morphogenetic protein 4 and retinoic acid promoted concentration-dependent differentiation of DECs. The resulting cells had a cobblestone appearance and keratin14 positivity. Attenuation of LiCl at stage 3 together with transforming growth factor ß1 and epidermal growth factor resulted in an ameloblast lineage with elongated cell morphology, positivity for ameloblast markers, and calcium deposition. Although stage-specific activation of Amelx did not produce noticeable phenotypic changes in ameloblast differentiation, Amelx activation at stage 3 significantly enhanced cell adhesion as well as decreased proliferation and migration. These results suggest that the combination of inducible Amelx transcription and stage-specific ameloblast induction for iPSCs represents a powerful tool to highlight underlying mechanisms in ameloblast differentiation and function in association with Amelx expression.


Assuntos
Ameloblastos/citologia , Ameloblastos/metabolismo , Amelogenina/metabolismo , Ameloblastos/fisiologia , Amelogenina/genética , Animais , Adesão Celular/fisiologia , Diferenciação Celular/fisiologia , Doxiciclina/farmacologia , Células Epiteliais/metabolismo , Células-Tronco Pluripotentes Induzidas/metabolismo , Camundongos , Transdução de Sinais , Ativação Transcricional/fisiologia
14.
Nucleic Acids Res ; 49(13): 7424-7436, 2021 07 21.
Artigo em Inglês | MEDLINE | ID: mdl-34197620

RESUMO

The pioneer transcription factor Pax7 contains two DNA binding domains (DBD), a paired and a homeo domain. Previous work on Pax7 and the related Pax3 showed that each DBD binds a cognate DNA sequence, thus defining two targets of binding and possibly modalities of action. Genomic targets of Pax7 pioneer action leading to chromatin opening are enriched for composite DNA target sites containing juxtaposed sites for both paired and homeo domains. The present work investigated the implication of the DBDs in pioneer action. We show that the composite sequence is a higher affinity binding site and that efficient binding to this site involves both DBDs of the same Pax7 molecule. This binding is not sensitive to cytosine methylation of the DNA sites consistent with pioneer action within nucleosomal heterochromatin. Introduction of single amino acid mutations in either paired or homeo domain that impair binding to cognate DNA sequences showed that both DBDs must be intact for pioneer action. In contrast, only the paired domain is required for low affinity binding of heterochromatin sites. Thus, Pax7 pioneer action on heterochromatin requires unique protein:DNA interactions that are more complex compared to its simpler DNA binding modalities at accessible enhancer target sites.


Assuntos
Fator de Transcrição PAX7/química , Fator de Transcrição PAX7/metabolismo , Sítios de Ligação , Células Cultivadas , Citosina/metabolismo , DNA/química , DNA/metabolismo , Metilação de DNA , Mutação , Motivos de Nucleotídeos , Fator de Transcrição PAX7/genética , Ligação Proteica , Domínios Proteicos , Ativação Transcricional
15.
Int J Mol Sci ; 22(11)2021 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-34200497

RESUMO

Left ventricular (LV) heart failure (HF) is a significant and increasing cause of death worldwide. HF is characterized by myocardial remodeling and excessive fibrosis. Transcriptional co-activator Yes-associated protein (Yap), the downstream effector of HIPPO signaling pathway, is an essential factor in cardiomyocyte survival; however, its status in human LV HF is not entirely elucidated. Here, we report that Yap is elevated in LV tissue of patients with HF, and is associated with down-regulation of its upstream inhibitor HIPPO component large tumor suppressor 1 (LATS1) activation as well as upregulation of the fibrosis marker connective tissue growth factor (CTGF). Applying the established profibrotic combined stress of TGFß and hypoxia to human ventricular cardiac fibroblasts in vitro increased Yap protein levels, down-regulated LATS1 activation, increased cell proliferation and collagen I production, and decreased ribosomal protein S6 and S6 kinase phosphorylation, a hallmark of mTOR activation, without any significant effect on mTOR and raptor protein expression or phosphorylation of mTOR or 4E-binding protein 1 (4EBP1), a downstream effector of mTOR pathway. As previously reported in various cell types, TGFß/hypoxia also enhanced cardiac fibroblast Akt and ERK1/2 phosphorylation, which was similar to our observation in LV tissues from HF patients. Further, depletion of Yap reduced TGFß/hypoxia-induced cardiac fibroblast proliferation and Akt phosphorylation at Ser 473 and Thr308, without any significant effect on TGFß/hypoxia-induced ERK1/2 activation or reduction in S6 and S6 kinase activities. Taken together, these data demonstrate that Yap is a mediator that promotes human cardiac fibroblast proliferation and suggest its possible contribution to remodeling of the LV, opening the door to further studies to decipher the cell-specific roles of Yap signaling in human HF.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Proliferação de Células , Insuficiência Cardíaca/patologia , Miofibroblastos/patologia , Proteínas Serina-Treonina Quinases/metabolismo , Fatores de Transcrição/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/genética , Estudos de Casos e Controles , Células Cultivadas , Feminino , Insuficiência Cardíaca/metabolismo , Humanos , Masculino , Miofibroblastos/metabolismo , Fosforilação , Proteínas Serina-Treonina Quinases/genética , Fatores de Transcrição/genética , Ativação Transcricional
16.
NPJ Biofilms Microbiomes ; 7(1): 54, 2021 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-34210981

RESUMO

Biofilm and nitrogen fixation are two competitive strategies used by many plant-associated bacteria; however, the mechanisms underlying the formation of nitrogen-fixing biofilms remain largely unknown. Here, we examined the roles of multiple signalling systems in the regulation of biofilm formation by root-associated diazotrophic P. stutzeri A1501. Physiological analysis, construction of mutant strains and microscale thermophoresis experiments showed that RpoN is a regulatory hub coupling nitrogen fixation and biofilm formation by directly activating the transcription of pslA, a major gene involved in the synthesis of the Psl exopolysaccharide component of the biofilm matrix and nifA, the transcriptional activator of nif gene expression. Genetic complementation studies and determination of the copy number of transcripts by droplet digital PCR confirmed that the regulatory ncRNA RsmZ serves as a signal amplifier to trigger biofilm formation by sequestering the translational repressor protein RsmA away from pslA and sadC mRNAs, the latter of which encodes a diguanylate cyclase that synthesises c-di-GMP. Moreover, RpoS exerts a braking effect on biofilm formation by transcriptionally downregulating RsmZ expression, while RpoS expression is repressed posttranscriptionally by RsmA. These findings provide mechanistic insights into how the Rpo/Gac/Rsm regulatory networks fine-tune nitrogen-fixing biofilm formation in response to the availability of nutrients.


Assuntos
Proteínas de Bactérias/genética , Biofilmes/crescimento & desenvolvimento , Regulação Bacteriana da Expressão Gênica , Redes Reguladoras de Genes , Fixação de Nitrogênio , Pseudomonas stutzeri/fisiologia , Proteínas de Bactérias/metabolismo , Ordem dos Genes , Nitrogenase/genética , Nitrogenase/metabolismo , Sequências Repetitivas de Ácido Nucleico , Ativação Transcricional
17.
Nat Commun ; 12(1): 4176, 2021 07 07.
Artigo em Inglês | MEDLINE | ID: mdl-34234134

RESUMO

Mammalian reovirus (MRV) is the prototypical member of genus Orthoreovirus of family Reoviridae. However, lacking high-resolution structures of its RNA polymerase cofactor µ2 and infectious particle, limits understanding of molecular interactions among proteins and RNA, and their contributions to virion assembly and RNA transcription. Here, we report the 3.3 Å-resolution asymmetric reconstruction of transcribing MRV and in situ atomic models of its capsid proteins, the asymmetrically attached RNA-dependent RNA polymerase (RdRp) λ3, and RdRp-bound nucleoside triphosphatase µ2 with a unique RNA-binding domain. We reveal molecular interactions among virion proteins and genomic and messenger RNA. Polymerase complexes in three Spinoreovirinae subfamily members are organized with different pseudo-D3d symmetries to engage their highly diversified genomes. The above interactions and those between symmetry-mismatched receptor-binding σ1 trimers and RNA-capping λ2 pentamers balance competing needs of capsid assembly, external protein removal, and allosteric triggering of endogenous RNA transcription, before, during and after infection, respectively.


Assuntos
Proteínas do Capsídeo/metabolismo , Nucleosídeo-Trifosfatase/metabolismo , Orthoreovirus/ultraestrutura , RNA Viral/metabolismo , Fatores de Transcrição/metabolismo , Regulação Alostérica , Animais , Proteínas do Capsídeo/ultraestrutura , Linhagem Celular , Microscopia Crioeletrônica , Regulação Viral da Expressão Gênica , Genoma Viral , Macaca mulatta , Nucleosídeo-Trifosfatase/ultraestrutura , Orthoreovirus/genética , Orthoreovirus/metabolismo , Multimerização Proteica , RNA de Cadeia Dupla/metabolismo , RNA de Cadeia Dupla/ultraestrutura , RNA Mensageiro/metabolismo , RNA Viral/ultraestrutura , RNA Polimerase Dependente de RNA/metabolismo , Fatores de Transcrição/ultraestrutura , Ativação Transcricional , Montagem de Vírus/genética
18.
Nat Commun ; 12(1): 4208, 2021 07 09.
Artigo em Inglês | MEDLINE | ID: mdl-34244516

RESUMO

The transcriptional regulators underlying induction and differentiation of dense connective tissues such as tendon and related fibrocartilaginous tissues (meniscus and annulus fibrosus) remain largely unknown. Using an iterative approach informed by developmental cues and single cell RNA sequencing (scRNA-seq), we establish directed differentiation models to generate tendon and fibrocartilage cells from mouse embryonic stem cells (mESCs) by activation of TGFß and hedgehog pathways, achieving 90% induction efficiency. Transcriptional signatures of the mESC-derived cells recapitulate embryonic tendon and fibrocartilage signatures from the mouse tail. scRNA-seq further identify retinoic acid signaling as a critical regulator of cell fate switch between TGFß-induced tendon and fibrocartilage lineages. Trajectory analysis by RNA sequencing define transcriptional modules underlying tendon and fibrocartilage fate induction and identify molecules associated with lineage-specific differentiation. Finally, we successfully generate 3-dimensional engineered tissues using these differentiation protocols and show activation of mechanotransduction markers with dynamic tensile loading. These findings provide a serum-free approach to generate tendon and fibrocartilage cells and tissues at high efficiency for modeling development and disease.


Assuntos
Fibrocartilagem/crescimento & desenvolvimento , Células-Tronco Embrionárias Murinas/fisiologia , Tendões/crescimento & desenvolvimento , Engenharia Tecidual/métodos , Ativação Transcricional , Animais , Diferenciação Celular/genética , Embrião de Mamíferos , Fibrocartilagem/citologia , Regulação da Expressão Gênica no Desenvolvimento , Proteínas Hedgehog/metabolismo , Mecanotransdução Celular/genética , Camundongos , RNA-Seq , Transdução de Sinais/genética , Análise de Célula Única , Tendões/citologia , Fator de Crescimento Transformador beta/metabolismo , Tretinoína/metabolismo
19.
Nutrients ; 13(7)2021 Jun 29.
Artigo em Inglês | MEDLINE | ID: mdl-34209567

RESUMO

Collagen tripeptide (CTP) is defined as a functional food material derived from collagenase digests of type I collagen and contains a high concentration of tripeptides with a Gly-X-Y sequence. CTP has several biological effects, including the acceleration of fracture healing, ameliorating osteoarthritis, and improving dryness and photoaging of the skin. Recently, an antiatherosclerotic effect of CTP has been reported, although its molecular mechanism is yet to be determined. In this study, we examined the effects of CTP on primary cultured human aortic endothelial cells (HAECs) under oxidative stress, because oxidative endothelial dysfunction is a trigger of atherosclerosis. DNA microarray and RT-qPCR analyses showed that CTP treatment recovered the downregulated expression of several genes, including the interleukin-3 receptor subunit alpha (IL3RA), which were suppressed by reactive oxygen species (ROS) treatment in HAECs. Furthermore, IL3RA knockdown significantly decreased the viability of HAECs compared with control cells. RT-qPCR analysis also showed that solute carrier 15 family peptide transporters, which are involved in CTP absorption into cells, were expressed in HAECs at levels more than comparable to those of a CTP-responsive human osteoblastic cell line. These results indicated that CTP exerts a protective effect for HAECs, at least in part, by regulating the recovery of ROS-induced transcriptional repression.


Assuntos
Aorta/citologia , Colágeno Tipo I/farmacologia , Células Endoteliais/efeitos dos fármacos , Substâncias Protetoras/farmacologia , Ativação Transcricional/efeitos dos fármacos , Aterosclerose/prevenção & controle , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Regulação para Baixo/efeitos dos fármacos , Alimento Funcional/análise , Humanos , Subunidade alfa de Receptor de Interleucina-3/efeitos dos fármacos , Osteoblastos , Estresse Oxidativo , Transportador 1 de Peptídeos/metabolismo , Espécies Reativas de Oxigênio/metabolismo
20.
Nat Commun ; 12(1): 4319, 2021 07 14.
Artigo em Inglês | MEDLINE | ID: mdl-34262032

RESUMO

Despite the genetic inactivation of SMARCA4, a core component of the SWI/SNF-complex commonly found in cancer, there are no therapies that effectively target SMARCA4-deficient tumours. Here, we show that, unlike the cells with activated MYC oncogene, cells with SMARCA4 inactivation are refractory to the histone deacetylase inhibitor, SAHA, leading to the aberrant accumulation of H3K27me3. SMARCA4-mutant cells also show an impaired transactivation and significantly reduced levels of the histone demethylases KDM6A/UTX and KDM6B/JMJD3, and a strong dependency on these histone demethylases, so that its inhibition compromises cell viability. Administering the KDM6 inhibitor GSK-J4 to mice orthotopically implanted with SMARCA4-mutant lung cancer cells or primary small cell carcinoma of the ovary, hypercalcaemic type (SCCOHT), had strong anti-tumour effects. In this work we highlight the vulnerability of KDM6 inhibitors as a characteristic that could be exploited for treating SMARCA4-mutant cancer patients.


Assuntos
Antineoplásicos/uso terapêutico , DNA Helicases/deficiência , Histona Desmetilases/antagonistas & inibidores , Histona Desmetilases com o Domínio Jumonji/antagonistas & inibidores , Neoplasias/tratamento farmacológico , Proteínas Nucleares/deficiência , Fatores de Transcrição/deficiência , Animais , Antineoplásicos/farmacologia , Benzazepinas/farmacologia , Benzazepinas/uso terapêutico , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , DNA Helicases/metabolismo , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Expressão Gênica , Inibidores de Histona Desacetilases/farmacologia , Inibidores de Histona Desacetilases/uso terapêutico , Histona Desmetilases/genética , Histona Desmetilases/metabolismo , Histonas/metabolismo , Humanos , Histona Desmetilases com o Domínio Jumonji/genética , Histona Desmetilases com o Domínio Jumonji/metabolismo , Camundongos , Neoplasias/metabolismo , Proteínas Nucleares/metabolismo , Pirimidinas/farmacologia , Pirimidinas/uso terapêutico , Fatores de Transcrição/metabolismo , Ativação Transcricional
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