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Thyroid cancer diagnosis primarily relies on imaging techniques and cytological analyses. In cases where the diagnosis is uncertain, the quantification of molecular markers has been incorporated after cytological examination. This approach helps physicians to make surgical decisions, estimate cancer aggressiveness, and monitor the response to treatments. Despite the availability of commercial molecular tests, their widespread use has been hindered in our experience due to cost constraints and variability between them. Thus, numerous groups are currently evaluating new molecular markers that ultimately will lead to improved diagnostic certainty, as well as better classification of prognosis and recurrence. In this review, we start reviewing the current preoperative testing methodologies, followed by a comprehensive review of emerging molecular markers. We focus on micro RNAs, long non-coding RNAs, and mitochondrial (mt) signatures, including mtDNA genes and circulating cell-free mtDNA. We envision that a robust set of molecular markers will complement the national and international clinical guides for proper assessment of the disease.
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Biomarcadores Tumorais , DNA Mitocondrial , Mitocôndrias , Neoplasias da Glândula Tireoide , Humanos , Biomarcadores Tumorais/genética , Neoplasias da Glândula Tireoide/genética , Neoplasias da Glândula Tireoide/diagnóstico , Neoplasias da Glândula Tireoide/patologia , DNA Mitocondrial/genética , Mitocôndrias/metabolismo , Mitocôndrias/genética , RNA não Traduzido/genética , RNA Longo não Codificante/genética , MicroRNAs/genética , PrognósticoRESUMO
Astrocytes play a critical role in the maintenance of a healthy central nervous system and astrocyte dysfunction has been implicated in various neurodegenerative disorders, including amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). There is compelling evidence that mouse and human ALS and ALS/FTD astrocytes can reduce the number of healthy wild-type motoneurons (MNs) in co-cultures or after treatment with astrocyte conditioned media (ACM), independently of their genotype. A growing number of studies have shown that soluble toxic factor(s) in the ACM cause non-cell autonomous MN death, including our recent identification of inorganic polyphosphate (polyP) that is excessively released from mouse primary astrocytes (SOD1, TARDBP, and C9ORF72) and human induced pluripotent stem cells (iPSC)-derived astrocytes (TARDBP) to kill MNs. However, others have reported that astrocytes carrying mutant TDP43 do not produce detectable MN toxicity. This controversy is likely to arise from the findings that human iPSC-derived astrocytes exhibit a rather immature and/or reactive phenotype in a number of studies. Here, we have succeeded in generating a highly homogenous population of functional quiescent mature astrocytes from control subject iPSCs. Using identical conditions, we also generated mature astrocytes from an ALS/FTD patient carrying the TDP43A90V mutation. These mutant TDP43 patient-derived astrocytes exhibit key pathological hallmarks, including enhanced cytoplasmic TDP-43 and polyP levels. Additionally, mutant TDP43 astrocytes displayed a mild reactive signature and an aberrant function as they were unable to promote synaptogenesis of hippocampal neurons. The polyP-dependent neurotoxic nature of the TDP43A90V mutation was further confirmed as neutralization of polyP in ACM derived from mutant TDP43 astrocytes prevented MN death. Our results establish that human astrocytes carrying the TDP43A90V mutation exhibit a cell-autonomous pathological signature, hence providing an experimental model to decipher the molecular mechanisms underlying the generation of the neurotoxic phenotype.
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In cancer cells, the long non-coding RNA (lncRNA) MALAT1 has arisen as a key partner for the Polycomb Repressive Complex 2 (PRC2), an epigenetic modifier. However, it is unknown whether this partnership occurs genome-wide at the chromatin level, as most of the studies focus on single genes that are usually repressed. Due to the genomic binding properties of both macromolecules, we wondered whether there are binding sites shared by PRC2 and MALAT1. Using public genome-binding datasets for PRC2 and MALAT1 derived from independent ChIP- and CHART-seq experiments performed with the breast cancer cell line MCF7, we searched for regions containing PRC2 and MALAT1 overlapping peaks. Peak calls for each molecule were performed using MACS2 and then overlapping peaks were identified by bedtools intersect. Using this approach, we identified 1293 genomic sites where PRC2 and MALAT1 concur. Interestingly, 54.75% of those sites are within gene promoter regions (<3000 bases from the TSS). These analyses were also linked with the transcription profiles of MCF7 cells, obtained from public RNA-seq data. Hence, it is suggested that MALAT1 and PRC2 can concomitantly bind to promoters of actively-transcribed genes in MCF7 cells. Gene ontology analyses revealed an enrichment of genes related to categories including cancer malignancy and epigenetic regulation. Thus, by re-visiting occupancy and transcriptomic data, we identified a key gene subset controlled by the collaboration of MALAT1 and PRC2.
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RESUMEN Introducción. La prevalencia de uso del cigarrillo electrónico (CE) a nivel mundial ha ido en aumento en los últimos años, especialmente en la población joven. Objetivo. Conocer la frecuencia, percepción y el conocimiento sobre el cigarrillo electrónico en estudiantes de medicina de una universidad privada. Metodología. Estudio observacional, descriptivo de corte transversal en el que los datos se recolectaron por medio de una encuesta en formulario de Google. Los estudiantes recibieron vía aplicación de mensajería instantánea un link para responder el cuestionario. Las variables fueron: edad, sexo, uso del cigarrillo electrónico, hábito tabáquico, seguridad, eficacia como método para dejar de fumar, conocimiento sobre la composición del cigarrillo electrónico. Resultados. Respondieron la encuesta 506 estudiantes, de ellos 219 (43,3%) afirmaron utilizar CE. El 54,8% de los usuarios de CE era del sexo masculino y 41,6% tenía entre 22 - 26 años. El 41,0% considera que los CE son seguros, que es un método eficaz para dejar de fumar (57,1%), lo utilizaría para dejar de fumar (68,5%) y que se debería permitir su uso en lugares públicos (57,1%). Un porcentaje importante «desconoce» o considera que «no tienen» en su composición, dietilenglicol/propilenglicol (57,1%), glicerina (57,5%) o nicotina (16%), entre otros compuestos que podrían contener. Conclusión. La frecuencia de uso de CE en estudiantes de medicina de esta universidad es alta, la mayoría apoya su uso y desconoce su composición. Es necesario poner en práctica estrategias de prevención efectivas e informar sobre los riesgos para la salud relacionados con su uso.
ABSTRACT Introduction. The prevalence of electronic cigarette (EC) use worldwide has been increasing in recent years, especially in the young population. Objective. To know the frequency, perception and knowledge about the electronic cigarette in medical students of a private university. Methodology. Observational, descriptive cross-sectional study in which the data was collected through a Google form survey. Students received via instant messaging application a link to answer the questionnaire. The variables were: age, sex, use of the electronic cigarette, smoking habit, safety, efficacy as a method to quit smoking, knowledge about the composition of the electronic cigarette. Results. The survey was answered by 506 students, which 219 (43.3%) stated that they used CE. 54.8% of EC users were male and 41.6% were between 22-26 years old. 41.0% consider that EC is safe, that it is an effective method to quit smoking (57.1%), they would use it to quit smoking (68.5%) and that its use should be allowed in public places (57.1%). A significant percentage «does not know» or considers that they «do not have» in their composition, diethylene glycol/propylene glycol (57.1%), glycerin (57.5%) or nicotine (16%), among other compounds that they could contain. Conclusion. The frequency of EC use in medical students at this university is high, most of them support its use and are unaware of its composition. It is necessary to implement effective prevention strategies and inform about the health risks related to their use.
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Humanos , Masculino , Feminino , Adulto , Fumar Tabaco , Segurança , Abandono do Hábito de Fumar , Conhecimento , Sistemas Eletrônicos de Liberação de NicotinaRESUMO
Non-cell-autonomous mechanisms contribute to neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), in which astrocytes release unidentified factors that are toxic to motoneurons (MNs). We report here that mouse and patient iPSC-derived astrocytes with diverse ALS/FTD-linked mutations (SOD1, TARDBP, and C9ORF72) display elevated levels of intracellular inorganic polyphosphate (polyP), a ubiquitous, negatively charged biopolymer. PolyP levels are also increased in astrocyte-conditioned media (ACM) from ALS/FTD astrocytes. ACM-mediated MN death is prevented by degrading or neutralizing polyP in ALS/FTD astrocytes or ACM. Studies further reveal that postmortem familial and sporadic ALS spinal cord sections display enriched polyP staining signals and that ALS cerebrospinal fluid (CSF) exhibits increased polyP concentrations. Our in vitro results establish excessive astrocyte-derived polyP as a critical factor in non-cell-autonomous MN degeneration and a potential therapeutic target for ALS/FTD. The CSF data indicate that polyP might serve as a new biomarker for ALS/FTD.
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Esclerose Lateral Amiotrófica , Demência Frontotemporal , Esclerose Lateral Amiotrófica/genética , Animais , Astrócitos , Proteína C9orf72/genética , Meios de Cultivo Condicionados/farmacologia , Demência Frontotemporal/genética , Humanos , Camundongos , Neurônios Motores , PolifosfatosRESUMO
Abstract Cardiovascular diseases are the leading cause of death in the world. People living in vulnerable and poor places such as slums, rural areas and remote locations have difficulty in accessing medical care and diagnostic tests. In addition, given the COVID-19 pandemic, we are witnessing an increase in the use of telemedicine and non-invasive tools for monitoring vital signs. These questions motivate us to write this point of view and to describe some of the main innovations used for non-invasive screening of heart diseases. Smartphones are widely used by the population and are perfect tools for screening cardiovascular diseases. They are equipped with camera, flashlight, microphone, processor, and internet connection, which allow optical, electrical, and acoustic analysis of cardiovascular phenomena. Thus, when using signal processing and artificial intelligence approaches, smartphones may have predictive power for cardiovascular diseases. Here we present different smartphone approaches to analyze signals obtained from various methods including photoplethysmography, phonocardiograph, and electrocardiography to estimate heart rate, blood pressure, oxygen saturation (SpO2), heart murmurs and electrical conduction. Our objective is to present innovations in non-invasive diagnostics using the smartphone and to reflect on these trending approaches. These could help to improve health access and the screening of cardiovascular diseases for millions of people, particularly those living in needy areas.
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Inteligência Artificial/tendências , Doenças Cardiovasculares/diagnóstico , Triagem/tendências , Diagnóstico por Computador/métodos , Diagnóstico por Computador/tendências , Smartphone/tendências , Triagem/métodos , Telemedicina/métodos , Telemedicina/tendências , Aplicativos Móveis/tendências , Smartphone/instrumentação , Telecardiologia , COVID-19/diagnósticoRESUMO
The manufacturing process of the aircraft cabin interior panels is expensive and time-consuming, and the resulting panel requires rework due to damages that occurred during their fabrication. The aircraft interior panels must meet structural requirements; hence sandwich composites of a honeycomb core covered with two layers of pre-impregnated fiberglass skin are used. Flat sandwich composites are transformed into panels with complex shapes or geometries using the compression molding process, leading to advanced manufacturing challenges. Some aircraft interior panels are required for non-structural applications; hence sandwich composites can be substituted by cheaper alternative materials and transformed using disruptive manufacturing techniques. This paper evaluates the feasibility of replacing the honeycomb and fiberglass skin layers core with rigid polyurethane foams and thermoplastic polymers. The results show that the structural composites have higher mechanical performances than the proposed sandwich composites, but they are compatible with non-structural applications. Sandwich composite fabrication using the vacuum forming process is feasible for developing non-structural panels. This manufacturing technique is fast, easy, economical, and ecological as it uses recyclable materials. The vacuum forming also covers the entire panel, thus eliminating tapestries, paints, or finishes to the aircraft interior panels. The conclusion of the article describes the focus of future research.
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In this work, henequen and ixlte plant fibers were carbonized in a horizontal quartz tube furnace. Several carbonized and non-carbonized fiber fabric configurations were impregnated with a bio-based epoxy resin through the infuseon process. The infrared spectra revealed characteristic bands of styrene instead of organic compounds, representing that the carbonization procedure was adequate to carbonize the plant fibers. The porosity volume ratio for the non-carbonized henequen laminates showed the highest number of voids >1.9%, and the rest of the composites had a similar void density between 1.2-1.7%. The storage modulus of the non-carbonized and carbonized henequen laminates resulted in 2268.5 MPa and 2092.1 MPa, respectively. The storage modulus of the carbonized ixtle laminates was 1541.4 MPa, which is 37.8% higher than the non-carbonized ixtle laminates and 12% higher than henequen composites. The laminates were subject to thermal shock cycling, and tomography scans revealed no alterations on the porosity level or in the cracks after the cycling procedure. Thermal shock cycling promoted the post-curing effect by increasing the glass transition temperature. The viscoelastic results showed a variation in the storage modulus when the carbonized fiber fabrics were located between natural fiber fabrics, which was attributed to more excellent compaction during the infusion process. Variations in the viscoelastic behavior were observed between the different types of natural fibers, which influenced the mechanical properties.
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Accumulating evidence indicates that epigenetic control of gene expression plays a significant role during cell lineage commitment and subsequent cell fate maintenance. Here, we assess epigenetic mechanisms operating in the rat brain that mediate silencing of genes that are expressed during early and late stages of osteogenesis. We report that repression of the osteoblast master regulator Sp7 in embryonic (E18) hippocampus is mainly mediated through the Polycomb complex PRC2 and its enzymatic product H3K27me3. During early postnatal (P10), juvenile (P30), and adult (P90) hippocampal stages, the repressive H3K27me3 mark is progressively replaced by nucleosome enrichment and increased CpG DNA methylation at the Sp7 gene promoter. In contrast, silencing of the late bone phenotypic Bglap gene in the hippocampus is PRC2-independent and accompanied by strong CpG methylation from E18 through postnatal and adult stages. Forced ectopic expression of the primary master regulator of osteogenesis Runx2 in embryonic hippocampal neurons activates the expression of its downstream target Sp7 gene. Moreover, transcriptomic analyses show that several genes associated with the mesenchymal-osteogenic lineages are transcriptionally activated in these hippocampal cells that express Runx2 and Sp7. This effect is accompanied by a loss in neuronal properties, including a significant reduction in secondary processes at the dendritic arbor and reduced expression of critical postsynaptic genes like PSD95. Together, our results reveal a developmental progression in epigenetic control mechanisms that repress the expression of the osteogenic program in hippocampal neurons at embryonic, postnatal, and adult stages.
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Subunidade alfa 1 de Fator de Ligação ao Core/metabolismo , Epigênese Genética/genética , Hipocampo/metabolismo , Osteoblastos/metabolismo , Regiões Promotoras Genéticas/genética , Fatores de Transcrição/metabolismo , Acetilação , Animais , Western Blotting , Células Cultivadas , Imunoprecipitação da Cromatina , Subunidade alfa 1 de Fator de Ligação ao Core/genética , Metilação de DNA/genética , Metilação de DNA/fisiologia , Feminino , Masculino , Microscopia de Fluorescência , Ratos , Reação em Cadeia da Polimerase em Tempo Real , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Fatores de Transcrição/genéticaRESUMO
Ezh2 is a catalytic subunit of the polycomb repressive complex 2 (PRC2) which mediates epigenetic gene silencing through depositing the mark histone H3 lysine 27 trimethylation (H3K27me3) at target genomic sequences. Previous studies have demonstrated that Enhancer of Zeste Homolog 2 (Ezh2) was differentially expressed during maturation of hippocampal neurons; in immature neurons, Ezh2 was abundantly expressed, whereas in mature neurons the expression Ezh2 was significantly reduced. Here, we report that Ezh2 is downregulated by microRNAs (miRs) that are expressed during the hippocampal maturation process. We show that, in mature hippocampal neurons, lethal-7 (let-7) and microRNA-124 (miR-124) are robustly expressed and can target cognate motifs at the 3'-UTR of the Ezh2 gene sequence to downregulate Ezh2 expression. Together, these data demonstrate that the PRC2 repressive activity during hippocampal maturation is controlled through a post-transcriptional mechanism that mediates Ezh2 downregulation in mature neurons.
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Regulação para Baixo/genética , Proteína Potenciadora do Homólogo 2 de Zeste/genética , Hipocampo/fisiologia , MicroRNAs/genética , Neurônios/fisiologia , Regiões 3' não Traduzidas/genética , Animais , Linhagem Celular , Epigênese Genética/genética , Feminino , Células HEK293 , Histonas/genética , Humanos , Complexo Repressor Polycomb 2/genética , Gravidez , Interferência de RNA/fisiologia , Ratos , Ratos Sprague-DawleyRESUMO
Using a mathematical model, we explore the problem of availability versus overdemand of critical hospital processes (e.g., critical beds) in the face of a steady epidemic expansion such as is occurring from the COVID-19 pandemic. In connection with the statistics of new cases per day, and the assumption of maximum quota, the dynamics associated with the variables number of hospitalized persons (critical occupants) and mortality in the system are explored. A parametric threshold condition is obtained, which involves a parameter associated with the minimum daily effort for not collapsing the system. To exemplify, we include some simulations for the case of Chile, based on a parameter of effort to be sustained with the purpose of lowering the daily infection rate.
Mediante un modelo matemático este trabajo explora la problemática de la disponibilidad versus sobredemanda de procesos críticos hospitalarias (por ejemplo, camas críticas) ante una fuerte expansión epidémica como la que está ocurriendo como consecuencia de la pandemia de COVID-19. En conexión con la estadística de nuevos casos diarios y el supuesto de cupo máximo, exploramos la dinámica asociada a las variables número de hospitalizados (ocupantes críticos) y mortalidad en el sistema. Obtenemos una condición paramétrica umbral que involucra un parámetro asociado al esfuerzo mínimo diario para el no colapso del sistema. En orden a ejemplificar, incluimos algunas simulaciones para el caso de Chile, en función de un parámetro de esfuerzo a sostener para bajar la tasa de infección diaria.
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Betacoronavirus , Infecções por Coronavirus/epidemiologia , Infecções por Coronavirus/prevenção & controle , Necessidades e Demandas de Serviços de Saúde/estatística & dados numéricos , Modelos Teóricos , Pandemias/prevenção & controle , Pneumonia Viral/epidemiologia , Pneumonia Viral/prevenção & controle , COVID-19 , Chile/epidemiologia , Infecções por Coronavirus/transmissão , Recursos em Saúde/provisão & distribuição , Número de Leitos em Hospital/estatística & dados numéricos , Hospitalização/estatística & dados numéricos , Humanos , Pneumonia Viral/transmissão , Valores de Referência , SARS-CoV-2 , Capacidade de Resposta ante Emergências/estatística & dados numéricosRESUMO
We present a straightforward projection with data up to 21/03/2020 of the evolution of the number of COVID-19 cases per day in Chile using data from the Ministry of Health. Assuming an arithmetical growth in the second variation of the data, we present a cubic adjustment model in which we estimate over 100 000 cases at 120 days consistent with the data recorded to date. Furthermore, we use an exponential total case model to represent (using a parameter) the daily effort to reduce a high initial daily growth rate. We simulate this model with different numerical scenarios of feasibility and desired future prevalence.
Realizamos una prospectiva básica, con datos al 21/03/2020 de la evolución del número de casos COVID-19 diarios en Chile con datos del Ministerio de Salud. Asumiendo un crecimiento aritmético en la segunda variación de los datos, se presenta un modelo de ajuste cúbico que estima en más de 100 mil casos a 120 días y que es consistente con los datos registrados a la fecha. Además, se interviene un modelo de casos totales exponencial, para representar en él (mediante un parámetro) el esfuerzo diario por rebajar una elevada primera tasa de crecimiento diario. Este modelo se simula con distinto escenarios numéricos de factibilidad y prevalencia futura deseada.
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Betacoronavirus , Infecções por Coronavirus/epidemiologia , Surtos de Doenças , Modelos Estatísticos , Pneumonia Viral/epidemiologia , COVID-19 , Chile/epidemiologia , Humanos , Pandemias , Prevalência , SARS-CoV-2RESUMO
Expression of Runx2/p57 is a hallmark of the osteoblast-lineage identity. Although several regulators that control the expression of Runx2/p57 during osteoblast-lineage commitment have been identified, the epigenetic mechanisms that sustain this expression in differentiated osteoblasts remain to be completely determined. Here, we assess epigenetic mechanisms associated with Runx2/p57 gene transcription in differentiating MC3T3 mouse osteoblasts. Our results show that an enrichment of activating histone marks at the Runx2/p57 P1 promoter is accompanied by the simultaneous interaction of Wdr5 and Utx proteins, both are components of COMPASS complexes. Knockdown of Wdr5 and Utx expression confirms the activating role of both proteins at the Runx2-P1 promoter. Other chromatin modifiers that were previously described to regulate Runx2/p57 transcription in mesenchymal precursor cells (Ezh2, Prmt5, and Jarid1b proteins) were not found to contribute to Runx2/p57 transcription in full-committed osteoblasts. We also determined the presence of additional components of COMPASS complexes at the Runx2/p57 promoter, evidencing that the Mll2/COMPASS- and Mll3/COMPASS-like complexes bind to the P1 promoter in osteoblastic cells expressing Runx2/p57 to modulate the H3K4me1 to H3K4me3 transition.
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Subunidade alfa 1 de Fator de Ligação ao Core/genética , Histona Desmetilases/genética , Histonas/genética , Peptídeos e Proteínas de Sinalização Intracelular/genética , Osteoblastos/metabolismo , Células 3T3 , Animais , Diferenciação Celular/fisiologia , Subunidade alfa 1 de Fator de Ligação ao Core/metabolismo , Epigênese Genética/genética , Regulação da Expressão Gênica/fisiologia , Histona Desmetilases/metabolismo , Histonas/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Camundongos , Osteoblastos/citologia , Transcrição GênicaRESUMO
Sertoli cells provide the nutritional and metabolic support for germ cells. Wnt/ß-catenin signaling is important for the development of the seminiferous epithelium during embryonic age, although after birth this pathway is downregulated. Cx43 gene codes for a protein that is critical during testicular development. The Cx43 promoter contains TCF/ß-catenin binding elements (TBEs) that contribute CX43 expression in different cell types and which may also be regulating the expression of this gene in Sertoli cells. In this study, we demonstrate that 42GPA9 Sertoli cells respond to treatments that result in accumulation of ß-catenin within the nucleus and in upregulation of CX43 gene transcription. ß-Catenin binds to TBEs located both upstream and downstream of the transcriptional start site (TSS). Luciferase reporter experiments revealed that TBEs located upstream of the TSS are necessary for ß-catenin-mediated upregulation. Our results also indicate that the Wnt/ß-catenin-dependent upregulation of the Cx43 gene in Sertoli cells is accompanied by changes in epigenetic parameters that may be directly contributing to generating a chromatin environment that facilitates the establishment of the transcriptional machinery at this promoter.
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Conexina 43/genética , Conexina 43/metabolismo , Regulação da Expressão Gênica , Regiões Promotoras Genéticas , Células de Sertoli/metabolismo , Proteínas Wnt/metabolismo , beta Catenina/metabolismo , Animais , Células Cultivadas , Epigênese Genética , Células HEK293 , Humanos , Masculino , Camundongos , Elementos de Resposta , Células de Sertoli/citologia , Ativação Transcricional , Proteínas Wnt/genética , beta Catenina/genéticaRESUMO
The Dlg4 gene encodes for post-synaptic density protein 95 (PSD95), a major synaptic protein that clusters glutamate receptors and is critical for plasticity. PSD95 levels are diminished in ageing and neurodegenerative disorders, including Alzheimer's disease and Huntington's disease. The epigenetic mechanisms that (dys)regulate transcription of Dlg4/PSD95, or other plasticity genes, are largely unknown, limiting the development of targeted epigenome therapy. We analysed the Dlg4/PSD95 epigenetic landscape in hippocampal tissue and designed a Dlg4/PSD95 gene-targeting strategy: a Dlg4/PSD95 zinc finger DNA-binding domain was engineered and fused to effector domains to either repress (G9a, Suvdel76, SKD) or activate (VP64) transcription, generating artificial transcription factors or epigenetic editors (methylating H3K9). These epi-editors altered critical histone marks and subsequently Dlg4/PSD95 expression, which, importantly, impacted several hippocampal neuron plasticity processes. Intriguingly, transduction of the artificial transcription factor PSD95-VP64 rescued memory deficits in aged and Alzheimer's disease mice. Conclusively, this work validates PSD95 as a key player in memory and establishes epigenetic editing as a potential therapy to treat human neurological disorders.
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Doença de Alzheimer/genética , Comportamento Animal , Cognição , Proteína 4 Homóloga a Disks-Large/genética , Repressão Epigenética , Hipocampo/metabolismo , Memória , Ativação Transcricional , Doença de Alzheimer/patologia , Doença de Alzheimer/fisiopatologia , Doença de Alzheimer/psicologia , Precursor de Proteína beta-Amiloide/genética , Animais , Modelos Animais de Doenças , Epigênese Genética , Código das Histonas , Humanos , Camundongos , Camundongos Transgênicos , Ratos , Dedos de ZincoRESUMO
Wharton's Jelly mesenchymal stem cells (WJ-MSCs) are an attractive potential source of multipotent stem cells for bone tissue replacement therapies. However, the molecular mechanisms involved in their osteogenic conversion are poorly understood. Particularly, epigenetic control operating at the promoter regions of the two master regulators of the osteogenic program, RUNX2/P57 and SP7 has not yet been described in WJ-MSCs. Via quantitative PCR profiling and chromatin immunoprecipitation (ChIP) studies, here we analyze the ability of WJ-MSCs to engage osteoblast lineage. In undifferentiated WJ-MSCs, RUNX2/P57 P1, and SP7 promoters are found deprived of significant levels of the histone post-translational marks that are normally associated with transcriptionally active genes (H3ac, H3K27ac, and H3K4me3). Moreover, the RUNX2 P1 promoter lacks two relevant histone repressive marks (H3K9me3 and H3K27me3). Importantly, RUNX2 P1 promoter is found highly enriched in the H3K4me1 mark, which has been shown recently to mediate gene repression of key regulatory genes. Upon induction of WJ-MSCs osteogenic differentiation, we found that RUNX2/P57, but not SP7 gene expression is strongly activated, in a process that is accompanied by enrichment of activating histone marks (H3K4me3, H3ac, and H3K27ac) at the P1 promoter region. Histone mark analysis showed that SP7 gene promoter is robustly enriched in epigenetic repressive marks that may explain its poor transcriptional response to osteoblast differentiating media. Together, these results point to critical regulatory steps during epigenetic control of WJ-MSCs osteogenic lineage commitment that are relevant for future applications in regenerative medicine. J. Cell. Physiol. 232: 2519-2527, 2017. © 2016 Wiley Periodicals, Inc.
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Diferenciação Celular , Linhagem da Célula , Subunidade alfa 1 de Fator de Ligação ao Core/metabolismo , Epigênese Genética , Células-Tronco Mesenquimais/metabolismo , Osteoblastos/metabolismo , Osteogênese , Regiões Promotoras Genéticas , Fatores de Transcrição/metabolismo , Transcriptoma , Geleia de Wharton/metabolismo , Células Cultivadas , Subunidade alfa 1 de Fator de Ligação ao Core/genética , Feminino , Regulação da Expressão Gênica no Desenvolvimento , Histonas/metabolismo , Humanos , Metilação , Fenótipo , Fator de Transcrição Sp7 , Fatores de Transcrição/genética , Transcrição Gênica , Ativação Transcricional , Geleia de Wharton/citologiaRESUMO
La demencia es un desorden que se caracteriza por un deterioro progresivo que limita la funcionalidad del individuo. Se han postulado varios factores de riesgo independientes para su desarrollo, entre ellos la enfermedad renal crónica. Se realizó un estudio transversal en 328 participantes mayores de 55 años, para determinar la prevalencia de demencia y los factores asociados en pacientes con enfermedad renal crónica. La función cognitiva de los participantes fue evaluada con la prueba cognitiva Montreal y el cuestionario de actividad funcional de Pfeffer. Se obtuvieron datos acerca de comorbilidades, valores de hemoglobina, creatinina sérica, índice de masa corporal y presión arterial. Se realizó un análisis descriptivo de la muestra, estimación de la de prevalencia de demencia y determinación de la asociación de factores de riesgo con el desarrollo de demencia por medio de regresión logística. El 16.6% de los sujetos fueron clasificados con demencia, IC 95% [12.82, 21.11] y 47.0% con deterioro cognitivo leve, IC 95% [41.54, 52.51]. Se encontró asociación positiva entre demencia y edad (OR 1.10, IC 95% [1.05, 1.15], p < .001), diabetes (OR 3.25, IC 95% [1.62, 6.50], p = .001), y antecedente de trauma craneoencefálico (OR 3.28, IC 95% [1.18, 9.09], p = .022). La asociación fue negativa con hemoglobina (OR 0.71, IC 95% [0.58, 0.88], p = .002) y tabaquismo (OR 0.31, IC 95% [0.13, 0.78], p = .012).
Dementia is a disorder characterized by progressive cognitive impairment, which limits the functionality of the affected individuals. Several independent risk factors have been postulated for its development, including chronic kidney disease. A cross-sectional design was performed in 328 subjects over 55 years old to determine the prevalence of dementia and associated risk factors in patients with chronic kidney disease. Two tests were administered to evaluate cognitive function: Montreal Cognitive Assessment and Pfeffer Functional Activities Questionnaire. Data of comorbidities, hemoglobin, serum creatinine, body mass index and blood pressure was collected. A descriptive analysis of the sample was performed, prevalence of dementia was estimated and associated factors were analyzed with a logistic regression model. 16.6% of subjects were classified as demented, whereas 47.0% had mild cognitive impairment. Significant association was found between: dementia and age (OR 1.10 CI 95% [1.05,1.15], p< .001), hemoglobin (OR .71 [.58, .88], p=.002, diabetes (OR 3.25 [1.62,6.50], p=.001), smoking (OR .31 [.13,.78], p=.012) and traumatic brain injury (OR 3.28 [1.18, 9.09], p=.022).
Assuntos
Pessoa de Meia-Idade , Prevalência , Fatores de Risco , Demência , Insuficiência Renal Crônica , Diálise Peritoneal/efeitos adversos , Diálise , Disfunção Cognitiva/diagnóstico , Disfunção Cognitiva/sangueRESUMO
During hippocampal neuron differentiation, the expression of critical inducers of non-neuronal cell lineages must be efficiently silenced. Runx2 transcription factor is the master regulator of mesenchymal cells responsible for intramembranous osteoblast differentiation and formation of the craniofacial bone tissue that surrounds and protects the central nervous system (CNS) in mammalian embryos. The molecular mechanisms that mediate silencing of the Runx2 gene and its downstream target osteogenic-related genes in neuronal cells have not been explored. Here, we assess the epigenetic mechanisms that mediate silencing of osteoblast-specific genes in CNS neurons. In particular, we address the contribution of histone epigenetic marks and histone modifiers on the silencing of the Runx2/p57 bone-related isoform in rat hippocampal tissues at embryonic to adult stages. Our results indicate enrichment of repressive chromatin histone marks and of the Polycomb PRC2 complex at the Runx2/p57 promoter region. Knockdown of PRC2 H3K27-methyltransferases Ezh2 and Ezh1, or forced expression of the Trithorax/COMPASS subunit Wdr5 activates Runx2/p57 mRNA expression in both immature and mature hippocampal cells. Together these results indicate that complementary epigenetic mechanisms progressively and efficiently silence critical osteoblastic genes during hippocampal neuron differentiation.
Assuntos
Envelhecimento/genética , Subunidade alfa 1 de Fator de Ligação ao Core/genética , Inativação Gênica , Neurônios/metabolismo , Osteoblastos/metabolismo , Complexo Repressor Polycomb 2/genética , Envelhecimento/metabolismo , Animais , Animais Recém-Nascidos , Diferenciação Celular , Cromatina/química , Cromatina/metabolismo , Subunidade alfa 1 de Fator de Ligação ao Core/metabolismo , Inibidor de Quinase Dependente de Ciclina p57/genética , Inibidor de Quinase Dependente de Ciclina p57/metabolismo , Embrião de Mamíferos , Regulação da Expressão Gênica no Desenvolvimento , Hipocampo/citologia , Hipocampo/metabolismo , Histonas/genética , Histonas/metabolismo , Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/metabolismo , Neurônios/citologia , Osteoblastos/citologia , Osteogênese/genética , Complexo Repressor Polycomb 2/metabolismo , Cultura Primária de Células , Ratos , Ratos Sprague-DawleyRESUMO
The development of the cerebral cortex is a dynamic and coordinated process in which cell division, cell death, migration, and differentiation must be highly regulated to acquire the final architecture and functional competence of the mature organ. Notch pathway is an important regulator of differentiation and it is essential to maintain neural stem cell (NSC) pool. Here, we studied the role of epigenetic modulators such as lysine-specific demethylase 1 (LSD1) and its interactor CoREST in the regulation of the Notch pathway activity during the development of the cerebral cortex. We found that CoREST and LSD1 interact in vitro with RBPJ-κ in the repressor complex and these proteins are released upon overexpression of Notch intracellular domain (NICD). We corroborated LSD1 and RBPJ-κ interaction in developing cerebral cortex and also found that LSD1 binds to the hes1 promoter. Knock-down of CoREST and LSD1 by in utero electroporation increases Hes1 expression in vivo and decreases Ngn2. Interestingly, we found a functional interaction between CoREST and LSD1 with Notch pathway. This conclusion is based on the observation that both the defects in neuronal migration and the increase in the number of cells expressing Sox2 and Tbr2 were associated to the knock-down of either CoREST or LSD1 and were reversed by the loss of Notch. These results demonstrate that CoREST and LSD1 downregulate the Notch pathway in the developing cerebral cortex, thus suggesting a role of epigenetic regulation in the fine tuning of cell differentiation. © 2016 Wiley Periodicals, Inc. Develop Neurobiol 76: 1360-1373, 2016.
Assuntos
Diferenciação Celular/fisiologia , Córtex Cerebral/crescimento & desenvolvimento , Cromatina/metabolismo , Proteínas Correpressoras/metabolismo , Epigênese Genética/genética , Histona Desmetilases/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Neurogênese/fisiologia , Linhagem Celular , Movimento Celular/fisiologia , Córtex Cerebral/metabolismo , Humanos , Receptores Notch/metabolismo , Transdução de SinaisRESUMO
Transcription factor Runx2 controls bone development and osteoblast differentiation by regulating expression of a significant number of bone-related target genes. Here, we report that transcriptional activation and repression of the Runx2 gene via its osteoblast-specific P1 promoter (encoding mRNA for the Runx2/p57 isoform) is accompanied by selective deposition and elimination of histone marks during differentiation of mesenchymal cells to the osteogenic and myoblastic lineages. These epigenetic profiles are mediated by key components of the Trithorax/COMPASS-like and Polycomb group complexes together with histone arginine methylases like PRMT5 and lysine demethylases like JARID1B/KDM5B. Importantly, knockdown of the H3K4me2/3 demethylase JARID1B, but not of the demethylases UTX and NO66, prevents repression of the Runx2 P1 promoter during myogenic differentiation of mesenchymal cells. The epigenetically forced expression of Runx2/p57 and osteocalcin, a classical bone-related target gene, under myoblastic-differentiation is accompanied by enrichment of the H3K4me3 and H3K27ac marks at the Runx2 P1 promoter region. Our results identify JARID1B as a key component of a potent epigenetic switch that controls mesenchymal cell fate into myogenic and osteogenic lineages.