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1.
Hepatology ; 77(2): 501-511, 2023 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-35989577

RESUMO

BACKGROUND AND AIMS: Porto-sinusoidal vascular disorder (PSVD) is a group of liver vascular diseases featuring lesions encompassing the portal venules and sinusoids unaccompanied by cirrhosis, irrespective of the presence/absence of portal hypertension. It can occur secondary to coagulation disorders or insult by toxic agents. However, the cause of PSVD remains unknown in most cases. Hereditary cases of PSVD are exceptionally rare, but they are of particular interest and may unveil genetic alterations and molecular mechanisms associated with the disease. APPROACH AND RESULTS: We performed genome sequencing of four patients and two healthy individuals of a large multigenerational Lebanese family with PSVD and identified a heterozygous deleterious variant (c.547C>T, p.R183W) of FCH and double SH3 domains 1 ( FCHSD1 ), an uncharacterized gene, in patients. This variant segregated with the disease, and its pattern of inheritance was suggestive of autosomal dominant with variable expressivity. RNA structural modelling of human FCHSD1 suggests that the C-to-T substitution at position 547, corresponding to FCHSD1R183W , may increase both messenger RNA (mRNA) and protein stability and its interaction with MTOR-associated protein, LST8 homolog, a key protein of the mechanistic target of rapamycin (mTOR pathway). These predictions were substantiated by biochemical analyses, which showed that FCHSD1R183W induced high FCHSD1 mRNA stability, overexpression of FCHSD1 protein, and an increase in mTORC1 activation. This human FCHSD1 variant was introduced into mice through CRISPR/Cas9 genome editing. Nine out of the 15 mice carrying the human FCHSD1R183W variant mimicked the phenotype of human PSVD, including splenomegaly and enlarged portal vein. CONCLUSIONS: Aberrant FCHSD1 structure and function leads to mTOR pathway overactivation and may cause PSVD.


Assuntos
Hipertensão Portal , Doenças Vasculares , Humanos , Camundongos , Animais , Predisposição Genética para Doença , Família Estendida , Serina-Treonina Quinases TOR/genética , Serina-Treonina Quinases TOR/metabolismo , Hipertensão Portal/metabolismo , Genômica
2.
Lancet Oncol ; 23(3): 341-352, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-35150601

RESUMO

BACKGROUND: Disparities in the genetic risk of cancer among various ancestry groups and populations remain poorly defined. This challenge is even more acute for Middle Eastern populations, where the paucity of genomic data could affect the clinical potential of cancer genetic risk profiling. We used data from the phase 1 cohort of the Qatar Genome Programme to investigate genetic variation in cancer-susceptibility genes in the Qatari population. METHODS: The Qatar Genome Programme generated high-coverage genome sequencing on DNA samples collected from 6142 native Qataris, stratified into six distinct ancestry groups: general Arab, Persian, Arabian Peninsula, Admixture Arab, African, and South Asian. In this population-based, cohort study, we evaluated the performance of polygenic risk scores for the most common cancers in Qatar (breast, prostate, and colorectal cancers). Polygenic risk scores were trained in The Cancer Genome Atlas (TCGA) dataset, and their distributions were subsequently applied to the six different genetic ancestry groups of the Qatari population. Rare deleterious variants within 1218 cancer susceptibility genes were analysed, and their clinical pathogenicity was assessed by ClinVar and the CharGer computational tools. FINDINGS: The cohort included in this study was recruited by the Qatar Biobank between Dec 11, 2012, and June 9, 2016. The initial dataset comprised 6218 cohort participants, and whole genome sequencing quality control filtering led to a final dataset of 6142 samples. Polygenic risk score analyses of the most common cancers in Qatar showed significant differences between the six ancestry groups (p<0·0001). Qataris with Arabian Peninsula ancestry showed the lowest polygenic risk score mean for colorectal cancer (-0·41), and those of African ancestry showed the highest average for prostate cancer (0·85). Cancer-gene rare variant analysis identified 76 Qataris (1·2% of 6142 individuals in the Qatar Genome Programme cohort) carrying ClinVar pathogenic or likely pathogenic variants in clinically actionable cancer genes. Variant analysis using CharGer identified 195 individuals carriers (3·17% of the cohort). Breast cancer pathogenic variants were over-represented in Qataris of Persian origin (22 [56·4%] of 39 BRCA1/BRCA2 variant carriers) and completely absent in those of Arabian Peninsula origin. INTERPRETATION: We observed a high degree of heterogeneity for cancer predisposition genes and polygenic risk scores across ancestries in this population from Qatar. Stratification systems could be considered for the implementation of national cancer preventive medicine programmes. FUNDING: Qatar Foundation.


Assuntos
Predisposição Genética para Doença , Neoplasias , Estudos de Coortes , Humanos , Masculino , Neoplasias/epidemiologia , Neoplasias/genética , Oncogenes , Catar/epidemiologia
3.
J Transl Med ; 18(1): 472, 2020 12 09.
Artigo em Inglês | MEDLINE | ID: mdl-33298113

RESUMO

Aberrant metabolism is the root cause of several serious health issues, creating a huge burden to health and leading to diminished life expectancy. A dysregulated metabolism induces the secretion of several molecules which in turn trigger the inflammatory pathway. Inflammation is the natural reaction of the immune system to a variety of stimuli, such as pathogens, damaged cells, and harmful substances. Metabolically triggered inflammation, also called metaflammation or low-grade chronic inflammation, is the consequence of a synergic interaction between the host and the exposome-a combination of environmental drivers, including diet, lifestyle, pollutants and other factors throughout the life span of an individual. Various levels of chronic inflammation are associated with several lifestyle-related diseases such as diabetes, obesity, metabolic associated fatty liver disease (MAFLD), cancers, cardiovascular disorders (CVDs), autoimmune diseases, and chronic lung diseases. Chronic diseases are a growing concern worldwide, placing a heavy burden on individuals, families, governments, and health-care systems. New strategies are needed to empower communities worldwide to prevent and treat these diseases. Precision medicine provides a model for the next generation of lifestyle modification. This will capitalize on the dynamic interaction between an individual's biology, lifestyle, behavior, and environment. The aim of precision medicine is to design and improve diagnosis, therapeutics and prognostication through the use of large complex datasets that incorporate individual gene, function, and environmental variations. The implementation of high-performance computing (HPC) and artificial intelligence (AI) can predict risks with greater accuracy based on available multidimensional clinical and biological datasets. AI-powered precision medicine provides clinicians with an opportunity to specifically tailor early interventions to each individual. In this article, we discuss the strengths and limitations of existing and evolving recent, data-driven technologies, such as AI, in preventing, treating and reversing lifestyle-related diseases.


Assuntos
Inteligência Artificial , Diabetes Mellitus , Doença Crônica , Diabetes Mellitus/terapia , Gerenciamento Clínico , Humanos , Medicina de Precisão
4.
Molecules ; 25(18)2020 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-32916777

RESUMO

Allium sativum (garlic) is widely known and is consumed as a natural prophylactic worldwide. It produces more than 200 identified chemical compounds, with more than 20 different kinds of sulfide compounds. The sulfide compounds particularly are proven to contribute to its various biological roles and pharmacological properties such as antimicrobial, antithrombotic, hypoglycemic, antitumour, and hypolipidemic. Therefore, it is often referred as disease-preventive food. Sulphur-containing compounds from A. sativum are derivatives of S-alkenyl-l-cysteine sulfoxides, ajoene molecules, thiosulfinates, sulfides, and S-allylcysteine. This review presents an overview of the water-soluble and oil-soluble sulphur based phytochemical compounds present in garlic, highlighting their mechanism of action in treating various health conditions. However, its role as a therapeutic agent should be extensively studied as it depends on factors such as the effective dosage and the suitable method of preparation.


Assuntos
Allium/química , Extratos Vegetais/farmacologia , Compostos de Enxofre/química , Animais , Anti-Infecciosos/química , Antineoplásicos/farmacologia , Plaquetas/efeitos dos fármacos , Cisteína/análogos & derivados , Cisteína/química , Dissulfetos/química , Fibrinólise , Alho/química , Humanos , Fatores Imunológicos/farmacologia , Neoplasias/tratamento farmacológico , Obesidade/tratamento farmacológico , Compostos Fitoquímicos/química , Solubilidade , Sulfóxidos/química , Enxofre/química
5.
Proc Natl Acad Sci U S A ; 112(13): E1550-8, 2015 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-25775580

RESUMO

The transcription factor caudal-type homeobox 1 (CDX1) is a key regulator of differentiation in the normal colon and in colorectal cancer (CRC). CDX1 activates the expression of enterocyte genes, but it is not clear how the concomitant silencing of stem cell genes is achieved. MicroRNAs (miRNAs) are important mediators of gene repression and have been implicated in tumor suppression and carcinogenesis, but the roles of miRNAs in differentiation, particularly in CRC, remain poorly understood. Here, we identified microRNA-215 (miR-215) as a direct transcriptional target of CDX1 by using high-throughput small RNA sequencing to profile miRNA expression in two pairs of CRC cell lines: CDX1-low HCT116 and HCT116 with stable CDX1 overexpression, and CDX1-high LS174T and LS174T with stable CDX1 knockdown. Validation of candidate miRNAs identified by RNA-seq in a larger cell-line panel revealed miR-215 to be most significantly correlated with CDX1 expression. Quantitative ChIP-PCR and promoter luciferase assays confirmed that CDX1 directly activates miR-215 transcription. miR-215 expression is depleted in FACS-enriched cancer stem cells compared with unsorted samples. Overexpression of miR-215 in poorly differentiated cell lines causes a decrease in clonogenicity, whereas miR-215 knockdown increases clonogenicity and impairs differentiation in CDX1-high cell lines. We identified the genome-wide targets of miR-215 and found that miR-215 mediates the repression of cell cycle and stemness genes downstream of CDX1. In particular, the miR-215 target gene BMI1 has been shown to promote stemness and self-renewal and to vary inversely with CDX1. Our work situates miR-215 as a link between CDX1 expression and BMI1 repression that governs differentiation in CRC.


Assuntos
Neoplasias Colorretais/metabolismo , Regulação Neoplásica da Expressão Gênica , Proteínas de Homeodomínio/metabolismo , MicroRNAs/metabolismo , Células-Tronco Neoplásicas/citologia , Diferenciação Celular , Linhagem Celular Tumoral , Colo/metabolismo , Ilhas de CpG , Perfilação da Expressão Gênica , Células HCT116 , Humanos , Complexo Repressor Polycomb 1/metabolismo , Análise de Sequência de RNA , Transfecção
6.
Arch Biochem Biophys ; 589: 108-19, 2016 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-26416722

RESUMO

The emergence of a worldwide obesity epidemic has dramatically increased the prevalence of insulin resistance and metabolic syndrome, predisposing individuals to a greater risk for the development of non-alcoholic fatty liver disease, type II diabetes and atherosclerotic cardiovascular diseases. Current available pharmacological interventions combined with diet and exercise-based managements are still poorly effective for weight management, likely in part due to an incomplete understanding of regulatory mechanisms and pathways contributing to the systemic metabolic abnormalities under disturbed energy homeostasis. MicroRNAs, small non-coding RNAs that regulate posttranscriptional gene expression, have been increasingly described to influence shifts in metabolic pathways under various obesity-related disease settings. Here we review recent discoveries of the mechanistic role that microRNAs play in regulating metabolic functions in liver and adipose tissues involved in obesity associated disorders, and briefly discusses the potential candidates that are being pursued as viable therapeutic targets.


Assuntos
MicroRNAs , Obesidade/complicações , Obesidade/genética , Adipogenia , Animais , Dislipidemias/complicações , Humanos , Resistência à Insulina , MicroRNAs/genética , Hepatopatia Gordurosa não Alcoólica/complicações , Obesidade/metabolismo , Obesidade/patologia
7.
EMBO Rep ; 12(7): 697-704, 2011 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-21566646

RESUMO

Targeting of messenger RNAs (mRNAs) in neuron processes relies on cis-acting regulatory elements, the nature of which is poorly understood. Here, we report that approximately 30% of the best-known dendritic mRNAs contain a guanine (G)-quadruplex consensus in their 3'-untranslated region. Among these mRNAs, we show by using RNA structure probing that a G-quadruplex is present in the mRNAs of two key postsynaptic proteins: PSD-95 and CaMKIIa. The G-quadruplex structure is necessary and sufficient for the potent and fast localization of mRNAs in cortical neurites and this occurs in a metabotropic glutamate receptor-responsive manner. Thus, G-quadruplex seems to be a common neurite localization signal.


Assuntos
Quadruplex G , Neuritos/metabolismo , Conformação de Ácido Nucleico , RNA Mensageiro/química , RNA Mensageiro/metabolismo , Animais , Sequência de Bases , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/genética , Proteína 4 Homóloga a Disks-Large , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/genética , Proteínas de Membrana/genética , Camundongos , Camundongos Endogâmicos C57BL , Dados de Sequência Molecular , Transporte de RNA
8.
Biotechnol Rep (Amst) ; 31: e00666, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34557392

RESUMO

We evaluated the seedling-stage salt tolerance of a total of 50 indigenous rice genotypes from coastal Tamil Nadu. Using a hydroponic system, we studied the different agronomic characters 14 days after exposure to six different concentrations of saline solution. Shoot and root length as well as plant biomass at seedling stage decreased with increasing salinity. Genotypes showing significant interaction and differential response towards salinity were assessed at the molecular level using 20 simple sequence repeat (SSR) markers linked with salt-tolerance QTL. These genotypes were grouped into eleven clusters based on molecular diversity analysis and eight clusters based on D2 statistical analysis. We found wide genetic distance among the genotypes studied. Simple correlation analysis revealed highly significant associations among the traits studied. The combination of morphological findings and molecular assessment revealed better salt-tolerance in a few genotypes viz. Kuzhi adichan, Poonkar, Kallundai, and Sornamugi.

9.
JCI Insight ; 6(5)2021 03 08.
Artigo em Inglês | MEDLINE | ID: mdl-33529170

RESUMO

The development of prophylactic and therapeutic agents for coronavirus disease 2019 (COVID-19) is a current global health priority. Here, we investigated the presence of cross-neutralizing antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in dromedary camels that were Middle East respiratory syndrome coronavirus (MERS-CoV) seropositive but MERS-CoV free. The tested 229 dromedaries had anti-MERS-CoV camel antibodies with variable cross-reactivity patterns against SARS-CoV-2 proteins, including the S trimer and M, N, and E proteins. Using SARS-CoV-2 competitive immunofluorescence immunoassays and pseudovirus neutralization assays, we found medium-to-high titers of cross-neutralizing antibodies against SARS-CoV-2 in these animals. Through linear B cell epitope mapping using phage immunoprecipitation sequencing and a SARS-CoV-2 peptide/proteome microarray, we identified a large repertoire of Betacoronavirus cross-reactive antibody specificities in these dromedaries and demonstrated that the SARS-CoV-2-specific VHH antibody repertoire is qualitatively diverse. This analysis revealed not only several SARS-CoV-2 epitopes that are highly immunogenic in humans, including a neutralizing epitope, but also epitopes exclusively targeted by camel antibodies. The identified SARS-CoV-2 cross-neutralizing camel antibodies are not proposed as a potential treatment for COVID-19. Rather, their presence in nonimmunized camels supports the development of SARS-CoV-2 hyperimmune camels, which could be a prominent source of therapeutic agents for the prevention and treatment of COVID-19.


Assuntos
Anticorpos Neutralizantes/imunologia , Camelus/imunologia , SARS-CoV-2/efeitos dos fármacos , SARS-CoV-2/imunologia , Anticorpos de Domínio Único/farmacologia , Animais , Anticorpos Neutralizantes/farmacologia , Anticorpos Antivirais/imunologia , Betacoronavirus/imunologia , COVID-19/imunologia , Camelus/virologia , Reações Cruzadas , Epitopos , Feminino , Humanos , Coronavírus da Síndrome Respiratória do Oriente Médio/imunologia , Coronavírus Relacionado à Síndrome Respiratória Aguda Grave/imunologia
10.
Nucleic Acids Res ; 36(15): 4902-12, 2008 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-18653529

RESUMO

The fragile X mental retardation protein (FMRP) is a RNA-binding protein proposed to post-transcriptionally regulate the expression of genes important for neuronal development and synaptic plasticity. We previously demonstrated that FMRP binds to its own FMR1 mRNA via a guanine-quartet (G-quartet) RNA motif. However, the functional effect of this binding on FMR1 expression was not established. In this work, we characterized the FMRP binding site (FBS) within the FMR1 mRNA by a site directed mutagenesis approach and we investigated its importance for FMR1 expression. We show that the FBS in the FMR1 mRNA adopts two alternative G-quartet structures to which FMRP can equally bind. While FMRP binding to mRNAs is generally proposed to induce translational regulation, we found that mutations in the FMR1 mRNA suppressing binding to FMRP do not affect its translation in cellular models. We show instead that the FBS is a potent exonic splicing enhancer in a minigene system. Furthermore, FMR1 alternative splicing is affected by the intracellular level of FMRP. These data suggest that the G-quartet motif present in the FMR1 mRNA can act as a control element of its alternative splicing in a negative autoregulatory loop.


Assuntos
Processamento Alternativo , Proteína do X Frágil da Deficiência Intelectual/genética , Quadruplex G , RNA Mensageiro/química , Sequências Reguladoras de Ácido Ribonucleico , Adenina/química , Animais , Sequência de Bases , Sítios de Ligação , Células Cultivadas , Éxons , Proteína do X Frágil da Deficiência Intelectual/metabolismo , Células HeLa , Humanos , Camundongos , Camundongos Knockout , Dados de Sequência Molecular , Mutagênese Sítio-Dirigida , Células PC12 , Biossíntese de Proteínas , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , RNA Mensageiro/metabolismo , Ratos
11.
Elife ; 62017 06 05.
Artigo em Inglês | MEDLINE | ID: mdl-28580901

RESUMO

Thousands of long noncoding RNAs (lncRNAs) have been discovered, yet the function of the vast majority remains unclear. Here, we show that a p53-regulated lncRNA which we named PINCR (p53-induced noncoding RNA), is induced ~100-fold after DNA damage and exerts a prosurvival function in human colorectal cancer cells (CRC) in vitro and tumor growth in vivo. Targeted deletion of PINCR in CRC cells significantly impaired G1 arrest and induced hypersensitivity to chemotherapeutic drugs. PINCR regulates the induction of a subset of p53 targets involved in G1 arrest and apoptosis, including BTG2, RRM2B and GPX1. Using a novel RNA pulldown approach that utilized endogenous S1-tagged PINCR, we show that PINCR associates with the enhancer region of these genes by binding to RNA-binding protein Matrin 3 that, in turn, associates with p53. Our findings uncover a critical prosurvival function of a p53/PINCR/Matrin 3 axis in response to DNA damage in CRC cells.


Assuntos
Neoplasias Colorretais/patologia , Dano ao DNA , Regulação da Expressão Gênica , Proteínas Associadas à Matriz Nuclear/metabolismo , RNA Longo não Codificante/metabolismo , Proteínas de Ligação a RNA/metabolismo , Proteína Supressora de Tumor p53/metabolismo , Linhagem Celular Tumoral , Proliferação de Células , Humanos
12.
Cell Rep ; 20(10): 2408-2423, 2017 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-28877474

RESUMO

Basal p53 levels are tightly suppressed under normal conditions. Disrupting this regulation results in elevated p53 levels to induce cell cycle arrest, apoptosis, and tumor suppression. Here, we report the suppression of basal p53 levels by a nuclear, p53-regulated long noncoding RNA that we termed PURPL (p53 upregulated regulator of p53 levels). Targeted depletion of PURPL in colorectal cancer cells results in elevated basal p53 levels and induces growth defects in cell culture and in mouse xenografts. PURPL associates with MYBBP1A, a protein that binds to and stabilizes p53, and inhibits the formation of the p53-MYBBP1A complex. In the absence of PURPL, MYBBP1A interacts with and stabilizes p53. Silencing MYBBP1A significantly rescues basal p53 levels and proliferation in PURPL-deficient cells, suggesting that MYBBP1A mediates the effect of PURPL in regulating p53. These results reveal a p53-PURPL auto-regulatory feedback loop and demonstrate a role for PURPL in maintaining basal p53 levels.


Assuntos
Neoplasias Colorretais/genética , RNA Longo não Codificante/genética , Proteína Supressora de Tumor p53/genética , Apoptose/genética , Apoptose/fisiologia , Ciclo Celular/genética , Ciclo Celular/fisiologia , Pontos de Checagem do Ciclo Celular/genética , Pontos de Checagem do Ciclo Celular/fisiologia , Linhagem Celular , Linhagem Celular Tumoral , Proliferação de Células/genética , Proliferação de Células/fisiologia , Neoplasias Colorretais/metabolismo , Proteínas de Ligação a DNA , Proteína Semelhante a ELAV 1/genética , Proteína Semelhante a ELAV 1/metabolismo , Células HCT116 , Humanos , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo , Proteínas de Transporte Nucleocitoplasmático/genética , Proteínas de Transporte Nucleocitoplasmático/metabolismo , RNA Longo não Codificante/fisiologia , Proteínas de Ligação a RNA , Fatores de Transcrição , Proteína Supressora de Tumor p53/metabolismo
13.
Methods Mol Biol ; 1206: 29-37, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25240884

RESUMO

We have recently developed a biochemical approach to isolate miRNA-bound mRNAs and have used this method to identify the genome-wide mRNAs regulated by the tumor suppressor miRNA miR-34a. This method involves transfection of cells with biotinylated miRNA mimics, streptavidin pulldown, RNA isolation, and qRT-PCR. The protocol in this chapter describes these steps and the issues that should be considered while designing such pulldown experiments.


Assuntos
MicroRNAs/metabolismo , RNA Mensageiro/metabolismo , RNA/isolamento & purificação , Reação em Cadeia da Polimerase em Tempo Real/métodos , Transfecção/métodos , Genes Supressores de Tumor , Células HeLa , Humanos , MicroRNAs/genética , RNA Mensageiro/genética , Estreptavidina/química
14.
J Cereb Blood Flow Metab ; 22(1): 105-17, 2002 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-11807400

RESUMO

The authors are systematically exploring pharmacologic preservation for temporarily unresuscitable exsanguination cardiac arrest in dogs. They hypothesized that the antioxidant Tempol improves cerebral outcome when added to aortic saline flush at the start of cardiac arrest. In study A, no drug (n = 8), Tempol 150 mg/kg (n = 4), or Tempol 300 mg/kg (n = 4) was added to 25 mL/kg saline flush at 24 degrees C (achieving mild cerebral hypothermia) at the start of 20-minute cardiac arrest. In study B, no drug (n = 8) or Tempol 300 mg/kg (n = 7) was added to 50 mL/kg saline flush at 2 degrees C (achieving moderate cerebral hypothermia) at the start of 40-minute cardiac arrest. Cardiac arrest was reversed with cardiopulmonary bypass. Mild hypothermia lasted for 12 hours, controlled ventilation was sustained to 24 hours, and intensive care was provided for up to 72 hours. In study A, overall performance category 1 or 2 (good outcome) was achieved in all eight dogs treated with Tempol compared with three of eight dogs in the control group ( P = 0.03). In study B, good outcome was achieved in all seven dogs treated with Tempol versus only two of 8 dogs in the control group ( P = 0.007). In both studies, neurologic deficit scores were significantly better in the Tempol group, but not total histologic damage scores. At 72 hours, electron paramagnetic resonance spectroscopy of Tempol revealed direct evidence for its presence in the brain. Single- and double-strand DNA damage, nitrotyrosine immunostaining, total antioxidant reserve, and ascorbate acid levels were similar between groups, and thiol levels were decreased after Tempol in study B. The authors conclude that when added to aortic saline flush at the start of prolonged cardiac arrest, the antioxidant Tempol can enhance mild or moderate hypothermic cerebral preservation in terms of improved functional outcome. The mechanisms involved in this beneficial effect need further clarification.


Assuntos
Encéfalo/efeitos dos fármacos , Óxidos N-Cíclicos/farmacologia , Parada Cardíaca/fisiopatologia , Hipotermia , Fármacos Neuroprotetores/farmacologia , Ressuscitação/métodos , Animais , Antioxidantes/farmacologia , Temperatura Corporal , Encéfalo/patologia , Encéfalo/fisiopatologia , Química Encefálica , Cães , Espectroscopia de Ressonância de Spin Eletrônica , Metemoglobinemia , Distribuição Aleatória , Marcadores de Spin , Fatores de Tempo
15.
FEBS Lett ; 588(16): 2610-5, 2014 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-24726728

RESUMO

MicroRNAs are potent regulators of gene expression and modulate multiple cellular processes including proliferation, differentiation and apoptosis. A number of microRNAs have been shown to be regulated by p53, the most frequently mutated gene in human cancer. It is has been demonstrated that some mutant p53 proteins not only lose tumor suppressor activity, but also acquire novel oncogenic functions that are independent of wild-type p53. In this review, we highlight recent evidences suggesting that some mutant p53 proteins regulate the expression of specific microRNAs to gain oncogenic functions and identify a gene network regulated by the microRNAs downstream of mutant p53.


Assuntos
Redes Reguladoras de Genes , MicroRNAs/genética , Mutação , Neoplasias/genética , Proteína Supressora de Tumor p53/genética , Proteína Supressora de Tumor p53/metabolismo , Animais , Humanos , Neoplasias/metabolismo
16.
Oncotarget ; 5(17): 7635-50, 2014 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-25245095

RESUMO

MicroRNAs (miRNAs) regulate the expression of hundreds of genes. However, identifying the critical targets within a miRNA-regulated gene network is challenging. One approach is to identify miRNAs that exert a context-dependent effect, followed by expression profiling to determine how specific targets contribute to this selective effect. In this study, we performed miRNA mimic screens in isogenic KRAS-Wild-type (WT) and KRAS-Mutant colorectal cancer (CRC) cell lines to identify miRNAs selectively targeting KRAS-Mutant cells. One of the miRNAs we identified as a selective inhibitor of the survival of multiple KRAS-Mutant CRC lines was miR-126. In KRAS-Mutant cells, miR-126 over-expression increased the G1 compartment, inhibited clonogenicity and tumorigenicity, while exerting no effect on KRAS-WT cells. Unexpectedly, the miR-126-regulated transcriptome of KRAS-WT and KRAS-Mutant cells showed no significant differences. However, by analyzing the overlap between miR-126 targets with the synthetic lethal genes identified by RNAi in KRAS-Mutant cells, we identified and validated a subset of miR-126-regulated genes selectively required for the survival and clonogenicity of KRAS-Mutant cells. Our strategy therefore identified critical target genes within the miR-126-regulated gene network. We propose that the selective effect of miR-126 on KRAS-Mutant cells could be utilized for the development of targeted therapy for KRAS mutant tumors.


Assuntos
Neoplasias Colorretais/genética , MicroRNAs/genética , Proteínas Proto-Oncogênicas/genética , Proteínas ras/genética , Animais , Linhagem Celular Tumoral , Neoplasias Colorretais/patologia , Feminino , Citometria de Fluxo , Perfilação da Expressão Gênica , Regulação Neoplásica da Expressão Gênica/genética , Xenoenxertos , Humanos , Immunoblotting , Camundongos , Camundongos Nus , Mutação , Proteínas Proto-Oncogênicas p21(ras) , Reação em Cadeia da Polimerase Via Transcriptase Reversa
17.
Mol Cell Biol ; 34(3): 533-50, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24277930

RESUMO

The tumor suppressor p21 acts as a cell cycle inhibitor and has also been shown to regulate gene expression by functioning as a transcription corepressor. Here, we identified p21-regulated microRNAs (miRNAs) by sequencing small RNAs from isogenic p21(+/+) and p21(-/-) cells. Three abundant miRNA clusters, miR-200b-200a-429, miR-200c-141, and miR-183-96-182, were downregulated in p21-deficient cells. Consistent with the known function of the miR-200 family and p21 in inhibition of the epithelial-mesenchymal transition (EMT), we observed EMT upon loss of p21 in multiple model systems. To explore a role of the miR-183-96-182 cluster in EMT, we identified its genome-wide targets and found that miR-183 and miR-96 repressed common targets, including SLUG, ZEB1, ITGB1, and KLF4. Reintroduction of miR-200, miR-183, or miR-96 in p21(-/-) cells inhibited EMT, cell migration, and invasion. Conversely, antagonizing miR-200 and miR-183-96-182 cluster miRNAs in p21(+/+) cells increased invasion and elevated the levels of VIM, ZEB1, and SLUG mRNAs. Furthermore, we found that p21 forms a complex with ZEB1 at the miR-183-96-182 cluster promoter to inhibit transcriptional repression of this cluster by ZEB1, suggesting a reciprocal feedback loop.


Assuntos
Inibidor de Quinase Dependente de Ciclina p21/genética , Transição Epitelial-Mesenquimal , Proteínas de Homeodomínio/genética , MicroRNAs/genética , Fatores de Transcrição/genética , Animais , Linhagem Celular , Movimento Celular/genética , Inibidor de Quinase Dependente de Ciclina p21/metabolismo , Perfilação da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Células HCT116 , Células HEK293 , Proteínas de Homeodomínio/metabolismo , Humanos , Immunoblotting , Integrina beta1/genética , Integrina beta1/metabolismo , Fator 4 Semelhante a Kruppel , Fatores de Transcrição Kruppel-Like/genética , Fatores de Transcrição Kruppel-Like/metabolismo , Família Multigênica , Mutação , Oligonucleotídeos Antissenso/genética , Ligação Proteica , Interferência de RNA , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Fatores de Transcrição da Família Snail , Fatores de Transcrição/metabolismo , Homeobox 1 de Ligação a E-box em Dedo de Zinco
18.
Cancers (Basel) ; 5(4): 1655-75, 2013 Dec 04.
Artigo em Inglês | MEDLINE | ID: mdl-24305655

RESUMO

In recent years, long non-coding RNAs (lncRNAs) have gained significant attention as a novel class of gene regulators. Although a small number of lncRNAs have been shown to regulate gene expression through diverse mechanisms including transcriptional regulation, mRNA splicing and translation, the physiological function and mechanism of action of the vast majority are not known. Profiling studies in cell lines and tumor samples have suggested a potential role of lncRNAs in cancer. Indeed, distinct lncRNAs have been shown to be embedded in the p53 and Rb networks, two of the major tumor suppressor pathways that control cell cycle progression and survival. Given the fact that inactivation of Rb and p53 is a hallmark of human cancer, in this review we discuss recent evidence on the function of lncRNAs in the Rb and p53 signaling pathways.

19.
J Clin Invest ; 123(10): 4479-88, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-24091329

RESUMO

Naive CD8+ T cells rely upon oxidation of fatty acids as a primary source of energy. After antigen encounter, T cells shift to a glycolytic metabolism to sustain effector function. It is unclear, however, whether changes in glucose metabolism ultimately influence the ability of activated T cells to become long-lived memory cells. We used a fluorescent glucose analog, 2-NBDG, to quantify glucose uptake in activated CD8+ T cells. We found that cells exhibiting limited glucose incorporation had a molecular profile characteristic of memory precursor cells and an increased capacity to enter the memory pool compared with cells taking up high amounts of glucose. Accordingly, enforcing glycolytic metabolism by overexpressing the glycolytic enzyme phosphoglycerate mutase-1 severely impaired the ability of CD8+ T cells to form long-term memory. Conversely, activation of CD8+ T cells in the presence of an inhibitor of glycolysis, 2-deoxyglucose, enhanced the generation of memory cells and antitumor functionality. Our data indicate that augmenting glycolytic flux drives CD8+ T cells toward a terminally differentiated state, while its inhibition preserves the formation of long-lived memory CD8+ T cells. These results have important implications for improving the efficacy of T cell-based therapies against chronic infectious diseases and cancer.


Assuntos
Linfócitos T CD8-Positivos/efeitos dos fármacos , Glicólise/efeitos dos fármacos , Melanoma Experimental/imunologia , Transferência Adotiva , Animais , Linfócitos T CD8-Positivos/enzimologia , Linfócitos T CD8-Positivos/imunologia , Vacinas Anticâncer , Linhagem Celular Tumoral , Movimento Celular , Sobrevivência Celular , Desoxiglucose/farmacologia , Metabolismo Energético , Proteína Forkhead Box O1 , Fatores de Transcrição Forkhead/metabolismo , Hexoquinase/antagonistas & inibidores , Hexoquinase/metabolismo , Humanos , Memória Imunológica , Imunoterapia Ativa , Melanoma Experimental/enzimologia , Melanoma Experimental/terapia , Camundongos , Camundongos Endogâmicos C57BL , Transplante de Neoplasias , Estresse Fisiológico , Linfócitos T/imunologia , Carga Tumoral
20.
Mol Cell Biol ; 32(13): 2530-48, 2012 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22547681

RESUMO

The microRNA miR-519 robustly inhibits cell proliferation, in turn triggering senescence and decreasing tumor growth. However, the molecular mediators of miR-519-elicited growth inhibition are unknown. Here, we systematically investigated the influence of miR-519 on gene expression profiles leading to growth cessation in HeLa human cervical carcinoma cells. By analyzing miR-519-triggered changes in protein and mRNA expression patterns and by identifying mRNAs associated with biotinylated miR-519, we uncovered two prominent subsets of miR-519-regulated mRNAs. One subset of miR-519 target mRNAs encoded DNA maintenance proteins (including DUT1, EXO1, RPA2, and POLE4); miR-519 repressed their expression and increased DNA damage, in turn raising the levels of the cyclin-dependent kinase (cdk) inhibitor p21. The other subset of miR-519 target mRNAs encoded proteins that control intracellular calcium levels (notably, ATP2C1 and ORAI1); their downregulation by miR-519 aberrantly elevated levels of cytosolic [Ca(2+)] storage in HeLa cells, similarly increasing p21 levels in a manner dependent on the Ca(2+)-activated kinases CaMKII and GSK3ß. The rises in levels of DNA damage, the Ca(2+) concentration, and p21 levels stimulated an autophagic phenotype in HeLa and other human carcinoma cell lines. As a consequence, ATP levels increased, and the level of activity of the AMP-activated protein kinase (AMPK) declined, further contributing to the elevation in the abundance of p21. Our results indicate that miR-519 promotes DNA damage, alters Ca(2+) homeostasis, and enhances energy production; together, these processes elevate the expression level of p21, promoting growth inhibition and cell survival.


Assuntos
Inibidor de Quinase Dependente de Ciclina p21/metabolismo , MicroRNAs/genética , MicroRNAs/metabolismo , Autofagia , Sequência de Bases , Cálcio/metabolismo , Canais de Cálcio/genética , Sinalização do Cálcio , ATPases Transportadoras de Cálcio/genética , Linhagem Celular Tumoral , Proliferação de Células , Sobrevivência Celular , Inibidor de Quinase Dependente de Ciclina p21/antagonistas & inibidores , Inibidor de Quinase Dependente de Ciclina p21/genética , Dano ao DNA , DNA Polimerase II/genética , Reparo do DNA , Enzimas Reparadoras do DNA/genética , Metabolismo Energético , Exodesoxirribonucleases/genética , Células HeLa , Humanos , Modelos Biológicos , Proteína ORAI1 , Proteínas de Ligação a Poli-ADP-Ribose , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , RNA Interferente Pequeno/genética , Proteína de Replicação A/genética , Transdução de Sinais
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