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1.
Am J Hum Genet ; 102(4): 620-635, 2018 04 05.
Artigo em Inglês | MEDLINE | ID: mdl-29625024

RESUMO

Genome-wide association studies (GWASs) and functional genomics approaches implicate enhancer disruption in islet dysfunction and type 2 diabetes (T2D) risk. We applied genetic fine-mapping and functional (epi)genomic approaches to a T2D- and proinsulin-associated 15q22.2 locus to identify a most likely causal variant, determine its direction of effect, and elucidate plausible target genes. Fine-mapping and conditional analyses of proinsulin levels of 8,635 non-diabetic individuals from the METSIM study support a single association signal represented by a cluster of 16 strongly associated (p < 10-17) variants in high linkage disequilibrium (r2 > 0.8) with the GWAS index SNP rs7172432. These variants reside in an evolutionarily and functionally conserved islet and ß cell stretch or super enhancer; the most strongly associated variant (rs7163757, p = 3 × 10-19) overlaps a conserved islet open chromatin site. DNA sequence containing the rs7163757 risk allele displayed 2-fold higher enhancer activity than the non-risk allele in reporter assays (p < 0.01) and was differentially bound by ß cell nuclear extract proteins. Transcription factor NFAT specifically potentiated risk-allele enhancer activity and altered patterns of nuclear protein binding to the risk allele in vitro, suggesting that it could be a factor mediating risk-allele effects. Finally, the rs7163757 proinsulin-raising and T2D risk allele (C) was associated with increased expression of C2CD4B, and possibly C2CD4A, both of which were induced by inflammatory cytokines, in human islets. Together, these data suggest that rs7163757 contributes to genetic risk of islet dysfunction and T2D by increasing NFAT-mediated islet enhancer activity and modulating C2CD4B, and possibly C2CD4A, expression in (patho)physiologic states.

2.
PLoS One ; 13(4): e0195788, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29659628

RESUMO

From whole organisms to individual cells, responses to environmental conditions are influenced by genetic makeup, where the effect of genetic variation on a trait depends on the environmental context. RNA-sequencing quantifies gene expression as a molecular trait, and is capable of capturing both genetic and environmental effects. In this study, we explore opportunities of using allele-specific expression (ASE) to discover cis-acting genotype-environment interactions (GxE)-genetic effects on gene expression that depend on an environmental condition. Treating 17 common, clinical traits as approximations of the cellular environment of 267 skeletal muscle biopsies, we identify 10 candidate environmental response expression quantitative trait loci (reQTLs) across 6 traits (12 unique gene-environment trait pairs; 10% FDR per trait) including sex, systolic blood pressure, and low-density lipoprotein cholesterol. Although using ASE is in principle a promising approach to detect GxE effects, replication of such signals can be challenging as validation requires harmonization of environmental traits across cohorts and a sufficient sampling of heterozygotes for a transcribed SNP. Comprehensive discovery and replication will require large human transcriptome datasets, or the integration of multiple transcribed SNPs, coupled with standardized clinical phenotyping.


Assuntos
Microambiente Celular , Regulação da Expressão Gênica , Interação Gene-Ambiente , Variação Genética , Fibras Musculares Esqueléticas/metabolismo , Músculo Esquelético/metabolismo , Metabolismo Energético , Estudos de Associação Genética , Genótipo , Humanos , Músculo Esquelético/citologia , Fenótipo , Polimorfismo de Nucleotídeo Único , Locos de Características Quantitativas
3.
Artigo em Inglês | MEDLINE | ID: mdl-28904552

RESUMO

In tropical America, principally in Northeastern Brazil, the leaf extract of Anacardium occidentale is traditionally used for treatment of different diseases. However, chemical and biological properties and activities of Anacardium occidentale are poorly investigated and known. Here, we evaluated the antioxidant and anti-inflammatory activities "in vitro" of leaf extract from Anacardium occidentale. Our results show that leaf extract exhibits antioxidant activity when used to treat RAW 264.7 macrophage cells. Antioxidant effects were observed by decrease in oxidative damage in macrophage cells treated with 0.5 µg/mL and 5 µg/mL of leaf extract. Moreover, leaf extract reversed oxidative damage and inflammatory parameters induced in LPS-stimulated RAW 264.7 macrophage cells. Leaf extract at 0.5 µg/mL and 5 µg/mL was able to inhibit release of TNF-α and IL-1ß in LPS-stimulated cells. Taken together, our results indicate antioxidant and anti-inflammatory effects of leaf extract from Anacardium occidentale and reveal the positive effects that intake of these products can mediate in biological system.

4.
J Med Food ; 2016 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-27602660

RESUMO

In South America, particularly in the Northeastern regions of Brazil, Turnera subulata leaf extract is used as an alternative traditional medicine approach for several types of chronic diseases, such as diabetes, hypertension, chronic pain, and general inflammation. Despite its widespread use, little is known about the medicinal properties of the plants of this genus. In this study, we evaluate the antioxidant and anti-inflammatory of T. subulata leaf extract in an in vitro model of inflammation, using lipopolysaccharide-stimulated RAW-264.7 macrophage cell line. We observed that cotreatment with T. subulata leaf extract was able to reduce the oxidative stress in cells due to inflammatory response. More importantly, we observed that the leaf extract was able to directly modulate inflammatory response by altering activity of members of the mitogen-activated protein kinase pathways. Our results demonstrate for the first time that T. subulata have antioxidant and anti-inflammatory properties, which warrant further investigation of the medicinal potential of this species.

5.
Nat Commun ; 7: 11764, 2016 06 29.
Artigo em Inglês | MEDLINE | ID: mdl-27353450

RESUMO

Type 2 diabetes (T2D) results from the combined effects of genetic and environmental factors on multiple tissues over time. Of the >100 variants associated with T2D and related traits in genome-wide association studies (GWAS), >90% occur in non-coding regions, suggesting a strong regulatory component to T2D risk. Here to understand how T2D status, metabolic traits and genetic variation influence gene expression, we analyse skeletal muscle biopsies from 271 well-phenotyped Finnish participants with glucose tolerance ranging from normal to newly diagnosed T2D. We perform high-depth strand-specific mRNA-sequencing and dense genotyping. Computational integration of these data with epigenome data, including ATAC-seq on skeletal muscle, and transcriptome data across diverse tissues reveals that the tissue-specific genetic regulatory architecture of skeletal muscle is highly enriched in muscle stretch/super enhancers, including some that overlap T2D GWAS variants. In one such example, T2D risk alleles residing in a muscle stretch/super enhancer are linked to increased expression and alternative splicing of muscle-specific isoforms of ANK1.


Assuntos
Diabetes Mellitus Tipo 2/genética , Diabetes Mellitus Tipo 2/metabolismo , Estudo de Associação Genômica Ampla , Músculo Esquelético/metabolismo , Alelos , Epigenômica , Feminino , Regulação da Expressão Gênica , Predisposição Genética para Doença , Humanos , Masculino , Polimorfismo de Nucleotídeo Único , RNA Mensageiro , Análise de Sequência de RNA
6.
Mol Neurobiol ; 53(1): 423-435, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25465239

RESUMO

SH-SY5Y cells, a neuroblastoma cell line that is a well-established model system to study the initial phases of neuronal differentiation, have been used in studies to elucidate the mechanisms of neuronal differentiation. In the present study, we investigated alterations of gene expression in SH-SY5Y cells during neuronal differentiation mediated by retinoic acid (RA) treatment. We evaluated important pathways involving nuclear factor kappa B (NF-κB), nuclear E2-related factor 2 (Nrf2), glycolytic, and p53 during neuronal differentiation. We also investigated the involvement of reactive oxygen species (ROS) in modulating the gene expression profile of those pathways by antioxidant co-treatment with Trolox®, a hydrophilic analogue of α-tocopherol. We found that RA treatment increases levels of gene expression of NF-κB, glycolytic, and antioxidant pathway genes during neuronal differentiation of SH-SY5Y cells. We also found that ROS production induced by RA treatment in SH-SY5Y cells is involved in gene expression profile alterations, chiefly in NF-κB, and glycolytic pathways. Antioxidant co-treatment with Trolox® reversed the effects mediated by RA NF-κB, and glycolytic pathways gene expression. Interestingly, co-treatment with Trolox® did not reverse the effects in antioxidant gene expression mediated by RA in SH-SY5Y. To confirm neuronal differentiation, we quantified endogenous levels of tyrosine hydroxylase, a recognized marker of neuronal differentiation. Our data suggest that during neuronal differentiation mediated by RA, changes in profile gene expression of important pathways occur. These alterations are in part mediated by ROS production. Therefore, our results reinforce the importance in understanding the mechanism by which RA induces neuronal differentiation in SH-SY5Y cells, principally due this model being commonly used as a neuronal cell model in studies of neuronal pathologies.


Assuntos
Diferenciação Celular/efeitos dos fármacos , Perfilação da Expressão Gênica , Glicólise/genética , Fator 2 Relacionado a NF-E2/genética , NF-kappa B/genética , Neurônios/citologia , Tretinoína/farmacologia , Proteína Supressora de Tumor p53/genética , Diferenciação Celular/genética , Linhagem Celular Tumoral , Regulação da Expressão Gênica/efeitos dos fármacos , Redes Reguladoras de Genes/efeitos dos fármacos , Glicólise/efeitos dos fármacos , Humanos , Fator 2 Relacionado a NF-E2/metabolismo , NF-kappa B/metabolismo , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/genética , Proteína Supressora de Tumor p53/metabolismo
7.
PLoS One ; 8(12): e82457, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-24349289

RESUMO

Neuroblastoma is the most common extracranial tumor and a major cause of infant cancer mortality worldwide. Despite its importance, little is known about its molecular mechanisms. A striking feature of this tumor is its clinical heterogeneity. Possible outcomes range from aggressive invasion to other tissues, causing patient death, to spontaneous disease regression or differentiation into benign ganglioneuromas. Several efforts have been made in order to find tumor progression markers. In this work, we have reconstructed the neuroblastoma regulatory network using an information-theoretic approach in order to find genes involved in tumor progression and that could be used as outcome predictors or as therapeutic targets. We have queried the reconstructed neuroblastoma regulatory network using an aggressive neuroblastoma metastasis gene signature in order to find its master regulators (MRs). MRs expression profiles were then investigated in other neuroblastoma datasets so as to detect possible clinical significance. Our analysis pointed MAX as one of the MRs of neuroblastoma progression. We have found that higher MAX expression correlated with favorable patient outcomes. We have also found that MAX expression and protein levels were increased during neuroblastoma SH-SY5Y cells differentiation. We propose that MAX is involved in neuroblastoma progression, possibly increasing cell differentiation by means of regulating the availability of MYC:MAX heterodimers. This mechanism is consistent with the results found in our SH-SY5Y differentiation protocol, suggesting that MAX has a more central role in these cells differentiation than previously reported. Overexpression of MAX has been identified as anti-tumorigenic in other works, but, to our knowledge, this is the first time that the link between the expression of this gene and malignancy was verified under physiological conditions.


Assuntos
Fatores de Transcrição de Zíper de Leucina Básica/genética , Regulação Neoplásica da Expressão Gênica , Redes Reguladoras de Genes , Neuroblastoma/genética , Neuroblastoma/patologia , Fatores de Transcrição de Zíper de Leucina e Hélice-Alça-Hélix Básicos/genética , Fatores de Transcrição de Zíper de Leucina e Hélice-Alça-Hélix Básicos/metabolismo , Fatores de Transcrição de Zíper de Leucina Básica/metabolismo , Linhagem Celular Tumoral , Análise por Conglomerados , Progressão da Doença , Perfilação da Expressão Gênica , Humanos , Modelos Biológicos , Neuroblastoma/metabolismo , Neuroblastoma/mortalidade , Transdução de Sinais , Células Tumorais Cultivadas
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