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Measurement of thermal properties of thin films is challenging. In particular, thermal characterization is very difficult in semi-transparent samples. Here, we use two photothermal methods to obtain information about the thermal diffusivity as well as thermal conductivity of azoheteroarene functionalized polymer thin layers. The photothermal beam deflection (PBD) method is employed to gather data directly on thermal conductivity and thermal diffusivity, while the thermal lens (TL) method is employed to measure the effective thermal diffusivity. Consequently, the thermal diffusivity of the layers is indirectly estimated from the effective thermal diffusivity using a well-established theoretical relationship. Despite the utilization of distinct methods, our study reveals a remarkable consistency in the highly accurate results obtained from both approaches. This remarkable agreement reaffirms the reliability and mutual compatibility of the employed methods, highlighting their shared ability to provide accurate and congruent outcomes.
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The influence of P3HT:PCBM ratio on thermal and transport properties of solar cells were determined by photothermal beam deflection spectrometry, which is advantageous tool for non-destructively study of bulk heterojunction layers of organic solar cells. P3HT:PCBM layers of different P3HT:PCBM ratios were deposited on top of PEDOT:PSS/ITO layers which were included in organic bulk-heterojunction solar cells. The thermal diffusivity, energy gap and charge carrier lifetime were measured at different illumination conditions and with a different P3HT:PCBM ratios. As expected, it was found that the energy band gap depends on the P3HT:PCBM ratio. Thermal diffusivity is decreasing, while charge carrier lifetime is increasing with PCBM concentration. Energy band gap was found to be independent on illumination intensity, while thermal diffusivity was increasing and carrier lifetime was decreasing with illumination intensity. The carrier lifetime exhibits qualitatively similar dependence on the PCBM concentration when compared to the open-circuit voltage of operating solar cells under AM1.5 illumination. BDS and standard I-V measurement yielded comparable results arguing that the former is suitable for characterization of organic solar cells.
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Clonal evolution drives treatment failure in multiple myeloma (MM). Here, we used a custom 372-gene panel to track genetic changes occurring during MM progression at different stages of the disease. A tumor-only targeted next-generation DNA sequencing was performed on 69 samples sequentially collected from 30 MM patients. The MAPK/ERK pathway was mostly affected with KRAS mutated in 47% of patients. Acquisition and loss of mutations were observed in 63% and 37% of patients, respectively. Four different patterns of mutation evolution were found: branching-, mutation acquisition-, mutation loss- and a stable mutational pathway. Better response to anti-myeloma therapy was more frequently observed in patients who followed the mutation loss-compared to the mutation acquisition pathway. More than two-thirds of patients had druggable genes mutated (including cases of heavily pre-treated disease). Only 7% of patients had a stable copy number variants profile. Consequently, a redistribution in stages according to R-ISS between the first and paired samples (R-ISSâ³) was seen. The higher the R-ISSâ³, the higher the risk of MM progression and death. We provided new insights into the genetics of MM evolution, especially in heavily pre-treated patients. Additionally, we confirmed that redefining R-ISS at MM relapse is of high clinical value.
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3'-hydroxy-3,4,5,4'-tetramethoxystilbene (DMU-214) belongs to methoxystilbenes family and is an active metabolite of 3,4,5,4'-tetramethoxystilbene (DMU-212). In several of our previous studies, the anti-apoptotic activity of DMU-214 was significantly higher than that of the parent compound, especially in ovarian cancer cells. Due to increased lipophilicity and limited solubility, methoxystilbenes require a solubilization strategy enabling DMU-214 administration to the aqueous environment. In this study, DMU-214-loaded liposomes were developed for the first time, and its antitumor activity was tested in the ovarian cancer model.First, several liposomal formulations of DMU-214 were obtained by the thin lipid film hydration method followed by extrusion and then characterized. The diameter of the resulting vesicles was in the range of 118.0-155.5 nm, and samples presented monodisperse size distribution. The release of DMU-214 from the studied liposomes was governed by the contribution of two mechanisms, Fickian diffusion and liposome relaxation.Subsequently, in vitro activity of DMU-214 in the form of a free compound or liposome-bound was studied, including commercial cell line SK-OV-3 and patient-derived ovarian cancer cells in monolayer and spheroid cell culture models. DMU-214 liposomal formulations were found to be more potent (had lower IC50 values) than the free DMU-214 both in the monolayer and, more significantly, in both examined spheroid models. The above results, with particular emphasis on the patient-derived ovarian cancer model, indicate the importance of further development of liposomal DMU-214 as a potential anticancer formulation for ovarian cancer treatment.
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Lipossomos , Neoplasias Ovarianas , Carcinoma Epitelial do Ovário , Linhagem Celular Tumoral , Feminino , Humanos , Neoplasias Ovarianas/tratamento farmacológico , Neoplasias Ovarianas/patologia , Resveratrol , EstilbenosRESUMO
Partial reprogramming by expression of reprogramming factors (Oct4, Sox2, Klf4 and c-Myc) for short periods of time restores a youthful epigenetic signature to aging cells and extends the life span of a premature aging mouse model. However, the effects of longer-term partial reprogramming in physiologically aging wild-type mice are unknown. Here, we performed various long-term partial reprogramming regimens, including different onset timings, during physiological aging. Long-term partial reprogramming lead to rejuvenating effects in different tissues, such as the kidney and skin, and at the organismal level; duration of the treatment determined the extent of the beneficial effects. The rejuvenating effects were associated with a reversion of the epigenetic clock and metabolic and transcriptomic changes, including reduced expression of genes involved in the inflammation, senescence and stress response pathways. Overall, our observations indicate that partial reprogramming protocols can be designed to be safe and effective in preventing age-related physiological changes. We further conclude that longer-term partial reprogramming regimens are more effective in delaying aging phenotypes than short-term reprogramming.
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Senilidade Prematura , Reprogramação Celular , Animais , Camundongos , Reprogramação Celular/genética , Envelhecimento/genética , Senescência Celular , Senilidade Prematura/genética , Modelos Animais de DoençasRESUMO
BACKGROUND: Liver fibrosis is a wound-healing response to tissue injury and inflammation hallmarked by the extracellular matrix (ECM) protein deposition in the liver parenchyma and tissue remodelling. Different cell types of the liver are known to play distinct roles in liver injury response. Hepatocytes and liver endothelial cells receive molecular signals indicating tissue injury and activate hepatic stellate cells which produce ECM proteins upon their activation. Despite the growing knowledge on the molecular mechanism underlying hepatic fibrosis in general, the cell-type-specific gene regulatory network associated with the initial response to hepatotoxic injury is still poorly characterized. RESULTS: In this study, we used thioacetamide (TAA) to induce hepatic injury in adult zebrafish. We isolated three major liver cell types - hepatocytes, endothelial cells and hepatic stellate cells - and identified cell-type-specific chromatin accessibility and transcriptional changes in an early stage of liver injury. We found that TAA induced transcriptional shifts in all three cell types hallmarked by significant alterations in the expression of genes related to fatty acid and carbohydrate metabolism, as well as immune response-associated and vascular-specific genes. Interestingly, liver endothelial cells exhibit the most pronounced response to liver injury at the transcriptome and chromatin level, hallmarked by the loss of their angiogenic phenotype. CONCLUSION: Our results uncovered cell-type-specific transcriptome and epigenome responses to early stage liver injury, which provide valuable insights into understanding the molecular mechanism implicated in the early response of the liver to pro-fibrotic signals.
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Células Endoteliais , Epigenômica , Animais , Fígado , Peixe-Zebra/genéticaRESUMO
The family of PIM serine/threonine kinases includes three highly conserved oncogenes, PIM1, PIM2, and PIM3, which regulate multiple prosurvival pathways and cooperate with other oncogenes such as MYC. Recent genomic CRISPR-Cas9 screens further highlighted oncogenic functions of PIMs in diffuse large B-cell lymphoma (DLBCL) cells, justifying the development of small-molecule PIM inhibitors and therapeutic targeting of PIM kinases in lymphomas. However, detailed consequences of PIM inhibition in DLBCL remain undefined. Using chemical and genetic PIM blockade, we comprehensively characterized PIM kinase-associated prosurvival functions in DLBCL and the mechanisms of PIM inhibition-induced toxicity. Treatment of DLBCL cells with SEL24/MEN1703, a pan-PIM inhibitor in clinical development, decreased BAD phosphorylation and cap-dependent protein translation, reduced MCL1 expression, and induced apoptosis. PIM kinases were tightly coexpressed with MYC in diagnostic DLBCL biopsies, and PIM inhibition in cell lines and patient-derived primary lymphoma cells decreased MYC levels as well as expression of multiple MYC-dependent genes, including PLK1. Chemical and genetic PIM inhibition upregulated surface CD20 levels in an MYC-dependent fashion. Consistently, MEN1703 and other clinically available pan-PIM inhibitors synergized with the anti-CD20 monoclonal antibody rituximab in vitro, increasing complement-dependent cytotoxicity and antibody-mediated phagocytosis. Combined treatment with PIM inhibitor and rituximab suppressed tumor growth in lymphoma xenografts more efficiently than either drug alone. Taken together, these results show that targeting PIM in DLBCL exhibits pleiotropic effects that combine direct cytotoxicity with potentiated susceptibility to anti-CD20 antibodies, justifying further clinical development of such combinatorial strategies. SIGNIFICANCE: These findings demonstrate that inhibition of PIM induces DLBCL cell death via MYC-dependent and -independent mechanisms and enhances the therapeutic response to anti-CD20 antibodies by increasing CD20 expression.
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Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Linfoma Difuso de Grandes Células B/tratamento farmacológico , Inibidores de Proteínas Quinases/farmacologia , Proteínas Proto-Oncogênicas c-myc/genética , Proteínas Proto-Oncogênicas c-pim-1/antagonistas & inibidores , Rituximab/farmacologia , Animais , Antígenos CD20 , Antineoplásicos Imunológicos/farmacologia , Apoptose , Proliferação de Células , Feminino , Humanos , Linfoma Difuso de Grandes Células B/genética , Linfoma Difuso de Grandes Células B/metabolismo , Linfoma Difuso de Grandes Células B/patologia , Camundongos , Camundongos SCID , Fosforilação , Proteínas Proto-Oncogênicas c-myc/metabolismo , Células Tumorais Cultivadas , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
The atrioventricular canal (AVC) is the site where key structures responsible for functional division between heart regions are established, most importantly, the atrioventricular (AV) conduction system and cardiac valves. To elucidate the mechanism underlying AVC development and function, we utilized transgenic zebrafish line sqet31Et expressing EGFP in the AVC to isolate this cell population and profile its transcriptome at 48 and 72 hpf. The zebrafish AVC transcriptome exhibits hallmarks of mammalian AV node, including the expression of genes implicated in its development and those encoding connexins forming low conductance gap junctions. Transcriptome analysis uncovered protein-coding and noncoding transcripts enriched in AVC, which have not been previously associated with this structure, as well as dynamic expression of epithelial-to-mesenchymal transition markers and components of TGF-ß, Notch, and Wnt signaling pathways likely reflecting ongoing AVC and valve development. Using transgenic line Tg(myl7:mermaid) encoding voltage-sensitive fluorescent protein, we show that abolishing the pacemaker-containing sinoatrial ring (SAR) through Isl1 loss of function resulted in spontaneous activation in the AVC region, suggesting that it possesses inherent automaticity although insufficient to replace the SAR. The SAR and AVC transcriptomes express partially overlapping species of ion channels and gap junction proteins, reflecting their distinct roles. Besides identifying conserved aspects between zebrafish and mammalian conduction systems, our results established molecular hallmarks of the developing AVC which underlies its role in structural and electrophysiological separation between heart chambers. This data constitutes a valuable resource for studying AVC development and function, and identification of novel candidate genes implicated in these processes.
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Genoma/genética , Valvas Cardíacas/fisiologia , Peixe-Zebra/genética , Animais , Animais Geneticamente Modificados/genética , Embrião não Mamífero/fisiologia , Regulação da Expressão Gênica no Desenvolvimento/genética , Genômica/métodos , Defeitos dos Septos Cardíacos/genética , Miocárdio/patologia , Organogênese/genética , Marca-Passo Artificial , Via de Sinalização Wnt/genética , Proteínas de Peixe-Zebra/genéticaRESUMO
Tissue homeostasis requires long-term lineage fidelity of somatic stem cells. Whether and how age-related changes in somatic stem cells impact the faithful execution of lineage decisions remains largely unknown. Here, we address this question using genome-wide chromatin accessibility and transcriptome analysis as well as single-cell RNA-seq to explore stem-cell-intrinsic changes in the aging Drosophila intestine. These studies indicate that in stem cells of old flies, promoters of Polycomb (Pc) target genes become differentially accessible, resulting in the increased expression of enteroendocrine (EE) cell specification genes. Consistently, we find age-related changes in the composition of the EE progenitor cell population in aging intestines, as well as a significant increase in the proportion of EE-specified intestinal stem cells (ISCs) and progenitors in aging flies. We further confirm that Pc-mediated chromatin regulation is a critical determinant of EE cell specification in the Drosophila intestine. Pc is required to maintain expression of stem cell genes while ensuring repression of differentiation and specification genes. Our results identify Pc group proteins as central regulators of lineage identity in the intestinal epithelium and highlight the impact of age-related decline in chromatin regulation on tissue homeostasis.
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Células-Tronco Adultas/metabolismo , Linhagem da Célula/genética , Proteínas de Drosophila/genética , Intestinos/citologia , Proteínas do Grupo Polycomb/genética , Envelhecimento/genética , Animais , Diferenciação Celular/genética , Cromatina/genética , Cromatina/metabolismo , Drosophila/genética , Proteínas de Drosophila/metabolismo , Enterócitos/metabolismo , Células Enteroendócrinas/metabolismo , Regulação da Expressão Gênica , Homeostase , Mucosa Intestinal/metabolismo , Proteínas do Grupo Polycomb/metabolismo , TranscriptomaRESUMO
AIM: The main goal of this investigation was to evaluate the influence of positive beta haemolytic streptococci culture from the genital tract on patients receiving radiation therapy who suffer from cervical cancer. The other aim was to observe radiation therapy complications. BACKGROUND: Group B streptococci (GBS), group C streptococci (GCS) and group G streptococci (GGS) have been described as frequent invasive pathogens in elderly patients, often in association with underlying medical conditions including immunodeficiency and cancer. MATERIALS AND METHODS: In the years 2006-2015, vaginal swabs from 452 patients were examined. A total of 118 women with positive beta haemolytic streptococci (BHS) groups A, B, C, F, G cultures were analysed, of whom 111 were diagnosed with cervix cancer of IB to IVA degree according to the FIGO 1988 clinical classification. RESULTS: Of the 452 patients suffering from cervix cancer 26.1% were positive for A, B, C, F or G group BHS isolated from the genital tract. All of the 114 examined strains were sensitive to beta-lactam antibiotics. The antimicrobials for which resistance was noted were erythromycin, clindamycin, ciprofloxacin and tetracycline. CONCLUSIONS: Positive cultures of BHS from the genital tract were demonstrated to occur in patients with cervix cancer. Complications were found during radiotherapy in 30 (27%) of these patients, including 20 (18%) patients suffering from clinical symptoms of inflammation. When beta-lactam antibiotics are not recommended because of allergy, sensitivity tests to other drugs are necessary.
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Organogenesis involves dynamic regulation of gene transcription and complex multipathway interactions. Despite our knowledge of key factors regulating various steps of heart morphogenesis, considerable challenges in understanding its mechanism still exist because little is known about their downstream targets and interactive regulatory network. To better understand transcriptional regulatory mechanism driving heart development and the consequences of its disruption in vivo, we performed time-series analyses of the transcriptome and genome-wide chromatin accessibility in isolated cardiomyocytes (CMs) from wild-type zebrafish embryos at developmental stages corresponding to heart tube morphogenesis, looping, and maturation. We identified genetic regulatory modules driving crucial events of heart development that contained key cardiac TFs and are associated with open chromatin regions enriched for DNA sequence motifs belonging to the family of the corresponding TFs. Loss of function of cardiac TFs Gata5, Tbx5a, and Hand2 affected the cardiac regulatory networks and caused global changes in chromatin accessibility profile, indicating their role in heart development. Among regions with differential chromatin accessibility in mutants were highly conserved noncoding elements that represent putative enhancers driving heart development. The most prominent gene expression changes, which correlated with chromatin accessibility modifications within their proximal promoter regions, occurred between heart tube morphogenesis and looping, and were associated with metabolic shift and hematopoietic/cardiac fate switch during CM maturation. Our results revealed the dynamic regulatory landscape throughout heart development and identified interactive molecular networks driving key events of heart morphogenesis.
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Montagem e Desmontagem da Cromatina , Regulação da Expressão Gênica no Desenvolvimento , Coração/crescimento & desenvolvimento , Miócitos Cardíacos/metabolismo , Transcriptoma , Animais , Células Cultivadas , Cromatina/genética , Redes Reguladoras de Genes , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Peixe-Zebra , Proteínas de Peixe-Zebra/genética , Proteínas de Peixe-Zebra/metabolismoRESUMO
: Vertebrate organs develop through a complex process which involves interaction between multiple signaling pathways at the molecular, cell, and tissue levels. Heart development is an example of such complex process which, when disrupted, results in congenital heart disease (CHD). This complexity necessitates a holistic approach which allows the visualization of genome-wide interaction networks, as opposed to assessment of limited subsets of factors. Genomics offers a powerful solution to address the problem of biological complexity by enabling the observation of molecular processes at a genome-wide scale. The emergence of next generation sequencing (NGS) technology has facilitated the expansion of genomics, increasing its output capacity and applicability in various biological disciplines. The application of NGS in various aspects of heart biology has resulted in new discoveries, generating novel insights into this field of study. Here we review the contributions of NGS technology into the understanding of heart development and its disruption reflected in CHD and discuss how emerging NGS based methodologies can contribute to the further understanding of heart repair.
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Planet formation theories predict that some planets may be ejected from their parent systems as result of dynamical interactions and other processes. Unbound planets can also be formed through gravitational collapse, in a way similar to that in which stars form. A handful of free-floating planetary-mass objects have been discovered by infrared surveys of young stellar clusters and star-forming regions as well as wide-field surveys, but these studies are incomplete for objects below five Jupiter masses. Gravitational microlensing is the only method capable of exploring the entire population of free-floating planets down to Mars-mass objects, because the microlensing signal does not depend on the brightness of the lensing object. A characteristic timescale of microlensing events depends on the mass of the lens: the less massive the lens, the shorter the microlensing event. A previous analysis of 474 microlensing events found an excess of ten very short events (1-2 days)-more than known stellar populations would suggest-indicating the existence of a large population of unbound or wide-orbit Jupiter-mass planets (reported to be almost twice as common as main-sequence stars). These results, however, do not match predictions of planet-formation theories and surveys of young clusters. Here we analyse a sample of microlensing events six times larger than that of ref. 11 discovered during the years 2010-15. Although our survey has very high sensitivity (detection efficiency) to short-timescale (1-2 days) microlensing events, we found no excess of events with timescales in this range, with a 95 per cent upper limit on the frequency of Jupiter-mass free-floating or wide-orbit planets of 0.25 planets per main-sequence star. We detected a few possible ultrashort-timescale events (with timescales of less than half a day), which may indicate the existence of Earth-mass and super-Earth-mass free-floating planets, as predicted by planet-formation theories.
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Nonalcoholic fatty liver disease prevalence is soaring with the obesity pandemic, but the pathogenic mechanisms leading to the progression toward active nonalcoholic steatohepatitis (NASH) and fibrosis, major causes of liver-related death, are poorly defined. To identify key components during the progression toward NASH and fibrosis, we investigated the liver transcriptome in a human cohort of NASH patients. The transition from histologically proven fatty liver to NASH and fibrosis was characterized by gene expression patterns that successively reflected altered functions in metabolism, inflammation, and epithelial-mesenchymal transition. A meta-analysis combining our and public human transcriptomic datasets with murine models of NASH and fibrosis defined a molecular signature characterizing NASH and fibrosis and evidencing abnormal inflammation and extracellular matrix (ECM) homeostasis. Dermatopontin expression was found increased in fibrosis, and reversal of fibrosis after gastric bypass correlated with decreased dermatopontin expression. Functional studies in mice identified an active role for dermatopontin in collagen deposition and fibrosis. PPARα activation lowered dermatopontin expression through a transrepressive mechanism affecting the Klf6/TGFß1 pathway. Liver fibrotic histological damages are thus characterized by the deregulated expression of a restricted set of inflammation- and ECM-related genes. Among them, dermatopontin may be a valuable target to reverse the hepatic fibrotic process.
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Obesity is a worldwide epidemic that predisposes individuals to cardiometabolic complications, such as type 2 diabetes mellitus (T2DM) and nonalcoholic fatty liver disease (NAFLD), which are all related to inappropriate ectopic lipid deposition. Identification of the pathogenic molecular mechanisms and effective therapeutic approaches are highly needed. The peroxisome proliferator-activated receptors (PPARs) modulate several biological processes that are perturbed in obesity, including inflammation, lipid and glucose metabolism and overall energy homeostasis. Here, we review how PPARs regulate the functions of adipose tissues, such as adipogenesis, lipid storage and adaptive thermogenesis, under healthy and pathological conditions. We also discuss the clinical use and mechanism of PPAR agonists in the treatment of obesity comorbidities such as dyslipidaemia, T2DM and NAFLD. First generation PPAR agonists, primarily those acting on PPARγ, are associated with adverse effects that outweigh their clinical benefits, which led to the discontinuation of their development. An improved understanding of the physiological roles of PPARs might, therefore, enable the development of safe, new PPAR agonists with improved therapeutic potential.
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Diabetes Mellitus Tipo 2/metabolismo , Dislipidemias/metabolismo , Hepatopatia Gordurosa não Alcoólica/metabolismo , Receptores Ativados por Proliferador de Peroxissomo/metabolismo , Animais , Diabetes Mellitus Tipo 2/patologia , Diabetes Mellitus Tipo 2/terapia , Dislipidemias/patologia , Dislipidemias/terapia , Humanos , Hepatopatia Gordurosa não Alcoólica/patologia , Hepatopatia Gordurosa não Alcoólica/terapia , Receptores Ativados por Proliferador de Peroxissomo/uso terapêuticoRESUMO
Adaptation to fasting involves both Glucocorticoid Receptor (GRα) and Peroxisome Proliferator-Activated Receptor α (PPARα) activation. Given both receptors can physically interact we investigated the possibility of a genome-wide cross-talk between activated GR and PPARα, using ChIP- and RNA-seq in primary hepatocytes. Our data reveal extensive chromatin co-localization of both factors with cooperative induction of genes controlling lipid/glucose metabolism. Key GR/PPAR co-controlled genes switched from transcriptional antagonism to cooperativity when moving from short to prolonged hepatocyte fasting, a phenomenon coinciding with gene promoter recruitment of phosphorylated AMP-activated protein kinase (AMPK) and blocked by its pharmacological inhibition. In vitro interaction studies support trimeric complex formation between GR, PPARα and phospho-AMPK. Long-term fasting in mice showed enhanced phosphorylation of liver AMPK and GRα Ser211. Phospho-AMPK chromatin recruitment at liver target genes, observed upon prolonged fasting in mice, is dampened by refeeding. Taken together, our results identify phospho-AMPK as a molecular switch able to cooperate with nuclear receptors at the chromatin level and reveal a novel adaptation mechanism to prolonged fasting.
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Adenilato Quinase/metabolismo , Cromatina/metabolismo , PPAR alfa/fisiologia , Receptores de Glucocorticoides/fisiologia , Animais , Sequência de Bases , Sítios de Ligação , Células Cultivadas , Elementos Facilitadores Genéticos , Jejum , Hepatócitos/metabolismo , Metabolismo dos Lipídeos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Transporte Proteico , Análise de Sequência de DNA , Ativação Transcricional , TranscriptomaRESUMO
Cataclysmic variable stars-novae, dwarf novae, and nova-likes-are close binary systems consisting of a white dwarf star (the primary) that is accreting matter from a low-mass companion star (the secondary). From time to time such systems undergo large-amplitude brightenings. The most spectacular eruptions, with a ten-thousandfold increase in brightness, occur in classical novae and are caused by a thermonuclear runaway on the surface of the white dwarf. Such eruptions are thought to recur on timescales of ten thousand to a million years. In between, the system's properties depend primarily on the mass-transfer rate: if it is lower than a billionth of a solar mass per year, the accretion becomes unstable and the matter is dumped onto the white dwarf during quasi-periodic dwarf nova outbursts. The hibernation hypothesis predicts that nova eruptions strongly affect the mass-transfer rate in the binary, keeping it high for centuries after the event. Subsequently, the mass-transfer rate should significantly decrease for a thousand to a million years, starting the hibernation phase. After that the nova awakes again-with accretion returning to the pre-eruption level and leading to a new nova explosion. The hibernation model predicts cyclical evolution of cataclysmic variables through phases of high and low mass-transfer. The theory gained some support from the discovery of ancient nova shells around the dwarf novae Z Camelopardalis and AT Cancri, but direct evidence for considerable mass-transfer changes prior, during and after nova eruptions has not hitherto been found. Here we report long-term observations of the classical nova V1213 Cen (Nova Centauri 2009) covering its pre- and post-eruption phases and precisely documenting its evolution. Within the six years before the explosion, the system revealed dwarf nova outbursts indicative of a low mass-transfer rate. The post-nova is two orders of magnitude brighter than the pre-nova at minimum light with no trace of dwarf nova behaviour, implying that the mass-transfer rate increased considerably as a result of the nova explosion.
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OBJECTIVES: The objective of the study was to evaluate the prevalence of sleep continuity disorders in women during menopausal transition, to evaluate the relationship between disturbances of sleep continuity and the severity of menopausal syndrome and the occurrence of various symptoms of this syndrome, as well as to evaluate the association between the presence of sleep disturbances and serum concentrations of gonadotropins, prolactin and sex hormones. METHODS: Consecutive 140 women (mean age 54.4 ± 4.7 years) searching for the treatment in the Clinic for Gynaecological Endocrinology who reported symptoms of menopausal syndrome were investigated. The type and severity of disturbances of sleep continuity were evaluated using a survey based on the sleep related questions from Hamilton Depression Rating Scale. The severity of symptoms of menopausal syndrome was assessed using the Kupperman Index. The concentration of the following hormones in blood serum was tested: FSH, LH, 17ß-estradiol, PRL, total testosterone, DHEAS and SHBG. RESULTS: Disturbances of sleep continuity were a prevalent complaint in the studied group of women. Difficulties in falling asleep were found in 57.8% of women, difficulties in maintaining sleep in 70%, waking up too early in 60.7%. The severity of all three types of sleep continuity disturbances was related to the severity of menopausal syndrome as measured with Kupperman Index (Spearman correlation coefficient r = 0.63, r = 0.61, r = 0.52, respectively; p < 0.001). Difficulties in maintaining sleep were negatively correlated with the concentration of FSH (r = - 0.19; p < 0.05), 17ß-estradiol (r = - 0.19; p < 0.05) and SHBG (r = - 0.18; p < 0.05), difficulties in falling asleep negatively correlated with the concentration of 17ß-estradiol in the blood serum (r = - 0.19; p < 0.05). CONCLUSIONS: Sleep continuity disturbances are frequently reported by women during the menopausal transition. Interventions aimed at reducing the symptoms of menopausal syndrome should be considered as important action to improve sleep quality in this population of patients.
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Menopausa/fisiologia , Transtornos do Sono-Vigília/sangue , Transtornos do Sono-Vigília/epidemiologia , Sono/fisiologia , Adulto , Idoso , Estradiol/sangue , Feminino , Hormônio Foliculoestimulante/sangue , Humanos , Menopausa/sangue , Pessoa de Meia-Idade , Prevalência , Prolactina/sangue , Índice de Gravidade de Doença , Transtornos do Sono-Vigília/classificação , Transtornos do Sono-Vigília/diagnóstico , Testosterona/sangueRESUMO
Acute liver failure (ALF) is a severe and rapid liver injury, often occurring without any preexisting liver disease, which may precipitate multiorgan failure and death. ALF is often associated with impaired ß-oxidation and increased oxidative stress (OS), characterized by elevated levels of hepatic reactive oxygen species (ROS) and lipid peroxidation (LPO) products. Peroxisome proliferator-activated receptor (PPAR)α has been shown to confer hepatoprotection in acute and chronic liver injury, at least in part, related to its ability to control peroxisomal and mitochondrial ß-oxidation. To study the pathophysiological role of PPARα in hepatic response to high OS, we induced a pronounced LPO by treating wild-type and Pparα-deficient mice with high doses of fish oil (FO), containing n-3 polyunsaturated fatty acids. FO feeding of Pparα-deficient mice, in contrast to control sunflower oil, surprisingly induced coma and death due to ALF as indicated by elevated serum alanine aminotransferase, aspartate aminotransferase, ammonia, and a liver-specific increase of ROS and LPO-derived malondialdehyde. Reconstitution of PPARα specifically in the liver using adeno-associated serotype 8 virus-PPARα in Pparα-deficient mice restored ß-oxidation and ketogenesis and protected mice from FO-induced lipotoxicity and death. Interestingly, administration of the ketone body ß-hydroxybutyrate prevented FO-induced ALF in Pparα-deficient mice, and normalized liver ROS and malondialdehyde levels. Therefore, PPARα protects the liver from FO-induced OS through its regulatory actions on ketone body levels. ß-Hydroxybutyrate treatment could thus be an option to prevent LPO-induced liver damage.
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Fígado Gorduroso/metabolismo , Corpos Cetônicos/química , Falência Hepática Aguda/metabolismo , PPAR alfa/deficiência , PPAR alfa/metabolismo , Ácido 3-Hidroxibutírico/química , Animais , Ácidos Graxos/metabolismo , Fígado Gorduroso/prevenção & controle , Feminino , Peroxidação de Lipídeos , Fígado/metabolismo , Falência Hepática Aguda/prevenção & controle , Camundongos , Camundongos Endogâmicos C57BL , Mitocôndrias/metabolismo , Oxirredução , Estresse Oxidativo , Peroxissomos/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Triglicerídeos/metabolismoRESUMO
Peroxisome proliferator-activated receptor α (PPARα) is a ligand-activated transcription factor belonging, together with PPARγ and PPARß/δ, to the NR1C nuclear receptor subfamily. Many PPARα target genes are involved in fatty acid metabolism in tissues with high oxidative rates such as muscle, heart and liver. PPARα activation, in combination with PPARß/δ agonism, improves steatosis, inflammation and fibrosis in pre-clinical models of non-alcoholic fatty liver disease, identifying a new potential therapeutic area. In this review, we discuss the transcriptional activation and repression mechanisms by PPARα, the spectrum of target genes and chromatin-binding maps from recent genome-wide studies, paying particular attention to PPARα-regulation of hepatic fatty acid and plasma lipoprotein metabolism during nutritional transition, and of the inflammatory response. The role of PPARα, together with other PPARs, in non-alcoholic steatohepatitis will be discussed in light of available pre-clinical and clinical data.