100 research outputs found
Teaching adults with intellectual disability to combine symbols in a reading context
The aim of this study is teaching adults con intellectual disability to combine symbols to convey semantic relations during shared reading. A single subject, multiple probe design across three different types of semantic relations generated from a matrix and replicated across three adults with moderate to severe intellectual disability was carried out. A prompts hierarchy in order to produce symbol combinations on an augmentative and alternative device was applied. Clear changes in trend and level were observed in the percentage of trained correct graphic-symbol combinations and the generalization of semantic relations to untrained combinations, and post-intervention maintenance of skills
L-methionine availability regulates expression of the methionine adenosyltransferase 2A gene in human hepatocarcinoma cells: role of S-adenosylmethionine
In mammals, methionine adenosyltransferase (MAT), the enzyme responsible for S-adenosylmethionine (AdoMet) synthesis, is encoded by two genes, MAT1A and MAT2A. In liver, MAT1A expression is associated with high AdoMet levels and a differentiated phenotype, whereas MAT2A expression is associated with lower AdoMet levels and a dedifferentiated phenotype. In the current study, we examined regulation of MAT2A gene expression by l-methionine availability using HepG2 cells. In l-methionine-deficient cells, MAT2A gene expression is rapidly induced, and methionine adenosyltransferase activity is increased. Restoration of l-methionine rapidly down-regulates MAT2A mRNA levels; for this effect, l-methionine needs to be converted into AdoMet. This novel action of AdoMet is not mediated through a methyl transfer reaction. MAT2A gene expression was also regulated by 5'-methylthioadenosine, but this was dependent on 5'-methylthioadenosine conversion to methionine through the salvage pathway. The transcription rate of the MAT2A gene remained unchanged during l-methionine starvation; however, its mRNA half-life was significantly increased (from 100 min to more than 3 h). The effect of l-methionine withdrawal on MAT2A mRNA stabilization requires both gene transcription and protein synthesis. We conclude that MAT2A gene expression is modulated as an adaptive response of the cell to l-methionine availability through its conversion to AdoMet
Lung cancer mortality attributable to residential radon exposure in Spain and its regions
Lung cancer has the highest cancer mortality rate in developed countries. The principal risk factor for lung cancer is tobacco use, with residential radon being the leading risk factor among never smokers and the second among ever smokers. We sought to estimate mortality attributable to residential radon exposure in Spain and its Autonomous Regions, with correction for dwelling height and differentiation by tobacco use. We applied a prevalence-based method for estimating attributable mortality. For estimations, we considered exposure to radon in the different Autonomous Regions corrected for dwelling height, using the National Statistics Institute Housing Census and prevalence of tobacco use (never smokers, smokers and ex-smokers). The results showed that 3.8% (838 deaths) of lung cancer mortality was attributable to radon exposure of over 100 Bq/m3, a figure that rises to 6.9% (1,533 deaths) when correction for dwelling height is not performed. By Autonomous Region, the highest population attributable fractions, corrected for dwelling height, were obtained for Galicia, Extremadura, and the Canary Islands, where 7.0, 6.9, and 5.5% of lung cancer mortality was respectively attributable to radon exposure. The greatest part of the attributable mortality occurred in men and among smokers and ex-smokers. Residential radon exposure is a major contributor to lung cancer mortality, though this contribution is highly variable among the different territories, indicating the need for targeted prevention policies. Correction of estimates for dwelling height is fundamental for providing reliable estimates of radon-attributable mortalityCarlos III Institute of Health (Instituto de Salud Carlos III) Project FIS PI19/00288S
5'-methylthioadenosine modulates the inflammatory response to endotoxin in mice and in rat hepatocytes
5'-methylthioadenosine (MTA) is a nucleoside generated from S-adenosylmethionine (AdoMet) during polyamine synthesis. Recent evidence indicates that AdoMet modulates in vivo the production of inflammatory mediators. We have evaluated the anti-inflammatory properties of MTA in bacterial lipopolysaccharide (LPS) challenged mice, murine macrophage RAW 264.7 cells, and isolated rat hepatocytes treated with pro-inflammatory cytokines. MTA administration completely prevented LPS-induced lethality. The life-sparing effect of MTA was accompanied by the suppression of circulating tumor necrosis factor-alpha (TNF-alpha), inducible NO synthase (iNOS) expression, and by the stimulation of IL-10 synthesis. These responses to MTA were also observed in LPS-treated RAW 264.7 cells. MTA prevented the transcriptional activation of iNOS by pro-inflammatory cytokines in isolated hepatocytes, and the induction of cyclooxygenase 2 (COX2) in RAW 264.7 cells. MTA inhibited the activation of p38 mitogen-activated protein kinase (MAPK), c-jun phosphorylation, inhibitor kappa B alpha (IkappaBalpha) degradation, and nuclear factor kappaB (NFkappaB) activation, all of which are signaling pathways related to the generation of inflammatory mediators. These effects were independent of the metabolic conversion of MTA into AdoMet and the potential interaction of MTA with the cAMP signaling pathway, central to the anti-inflammatory actions of its structural analog adenosine. In conclusion, these observations demonstrate novel immunomodulatory properties for MTA that may be of value in the management of inflammatory diseases
S-adenosylmethionine Levels Regulate the Schwann Cell DNA Methylome
SummaryAxonal myelination is essential for rapid saltatory impulse conduction in the nervous system, and malformation or destruction of myelin sheaths leads to motor and sensory disabilities. DNA methylation is an essential epigenetic modification during mammalian development, yet its role in myelination remains obscure. Here, using high-resolution methylome maps, we show that DNA methylation could play a key gene regulatory role in peripheral nerve myelination and that S-adenosylmethionine (SAMe), the principal methyl donor in cytosine methylation, regulates the methylome dynamics during this process. Our studies also point to a possible role of SAMe in establishing the aberrant DNA methylation patterns in a mouse model of diabetic neuropathy, implicating SAMe in the pathogenesis of this disease. These critical observations establish a link between SAMe and DNA methylation status in a defined biological system, providing a mechanism that could direct methylation changes during cellular differentiation and in diverse pathological situations
Fine-tuning of SIRT1 expression is essential to protect the liver from cholestatic liver disease
Cholestasis comprises aetiologically heterogeneous conditions characterized by accumulation of bile acids in the liver that actively contribute to liver damage. Sirtuin 1 (SIRT1) regulates liver regeneration and bile acid metabolism by modulating farnesoid X receptor (FXR); we here investigate its role in cholestatic liver disease. We determined SIRT1 expression in livers from patients with cholestatic disease, in two experimental models of cholestasis, as well as in human and murine liver cells in response to bile acid loading. SIRT1-overexpressing (SIRT oe ) and hepatocyte-specific SIRT1-KO (knockout) mice (SIRT hep–/– ) were subjected to bile duct ligation (BDL) and were fed with a 0.1% DDC (3,5-diethoxycarbonyl-1,4-dihydrocollidine) diet to determine the biological relevance of SIRT1 during cholestasis. The effect of NorUDCA (24-norursodeoxycholic acid) was tested in BDL/SIRT oe mice. We found that SIRT1 was highly expressed in livers from cholestatic patients, mice after BDL, and Mdr2 knockout mice (Mdr2 –/– ) animals. The detrimental effects of SIRT1 during cholestasis were validated in vivo and in vitro. SIRT oe mice showed exacerbated parenchymal injury whereas SIRT hep–/– mice evidenced a moderate improvement after BDL and 0.1% DDC feeding. Likewise, hepatocytes isolated from SIRT oe mice showed increased apoptosis in response to bile acids, whereas a significant reduction was observed in SIRT hep–/– hepatocytes. Importantly, the decrease, but not complete inhibition, of SIRT1 exerted by norUDCA treatment correlated with pronounced improvement in liver parenchyma in BDL/SIRT oe mice. Interestingly, both SIRT1 overexpression and hepatocyte-specific SIRT1 depletion correlated with inhibition of FXR, whereas modulation of SIRT1 by NorUDCA associated with restored FXR signaling. Conclusion: SIRT1 expression is increased during human and murine cholestasis. Fine-tuning expression of SIRT1 is essential to protect the liver from cholestatic liver damage
Fatty liver and fibrosis in glycine N-methyltransferase knockout mice is prevented by nicotinamide
Deletion of glycine N-methyltransferase (GNMT) in mice, the main gene involved in liver S-adenosylmethionine (SAMe) catabolism, leads to the hepatic accumulation of this molecule and the development of fatty liver and fibrosis. To demonstrate that the excess of hepatic SAMe is the main agent contributing to liver disease in GNMT-KO mice, we treated 1.5-month old GNMT-KO mice for 6 weeks with nicotinamide (NAM), a substrate of the enzyme NAM N-methyltransferase. NAM administration markedly reduced hepatic SAMe content, prevented DNA-hypermethylation and normalized the expression of critical genes involved in fatty acid metabolism, oxidative stress, inflammation, cell proliferation, and apoptosis. More important, NAM treatment prevented the development of fatty liver and fibrosis in GNMT-KO mice. Because GNMT expression is down-regulated in patients with cirrhosis and there are subjects with GNMT mutations who have spontaneous liver disease, the clinical implication of the present findings is obvious at least with respect to these latter individuals. Especially since NAM has been used for many years to treat a broad spectrum of diseases including pellagra and diabetes without significant side effects, it should be considered in subjects with GNMT mutations.ConclusionsThese results indicate that the anomalous accumulation of SAMe in GNMT-KO mice can be corrected by NAM treatment leading to the normalization of the expression of many genes involved in fatty acid metabolism, oxidative stress, inflammation, cell proliferation and apoptosis, and to the reversion of the appearance of the pathologic phenotype
Guía gallega de manejo de la trombosis asociada a cáncer. II edición
Esta guía práctica y sencilla, guiará en el diagnóstico y tratamiento de los pacientes con trombosis y cáncer. Pretende reducir la variabilidad en el manejo en la Comunidad Autónoma de Galicia y reducir el impacto negativo que la trombosis presenta en los pacientes con cáncer.This practical and simple guide will guide in the diagnosis and treatment of patients with thrombosis and cancer. It aims to reduce variability in management in the Autonomous Community of Galicia and reduce the negative impact that thrombosis has on cancer patients.Esta guía práctica e sinxela, guiará no diagnóstico e tratamento dos pacientes con trombose e cancro. Pretende reducir a variabilidade no manexo na Comunidade Autónoma de Galicia, e reducir o impacto negativo que a trombose presenta nos pacientes con cancro.Con el Aval de la Sociedad Oncológica de Galicia (SOG) y la Sociedade Galega de Medicina Interna (SOGAMI). Publicado en Barcelona por Bubblegum Communication Services el 25 de ocutubre de 2019. ISBN: 978-84-09-1419-4LEO Pharm
Enhanced mitochondrial activity reshapes a gut microbiota profile that delays NASH progression
[EN] Background and Aims: Recent studies suggest that mitochondrial dysfunction promotes progression to NASH by aggravating the gut-liver status. However, the underlying mechanism remains unclear. Herein, we hypothesized that enhanced mitochondrial activity might reshape a specific microbiota signature that, when transferred to germ-free (GF) mice, could delay NASH progression. Approach and Results: Wild-type and methylation-controlled J protein knockout (MCJ-KO) mice were fed for 6 weeks with either control or a choline-deficient, L-amino acid–defined, high-fat diet (CDA-HFD). One mouse of each group acted as a donor of cecal microbiota to GF mice, who also underwent the CDA-HFD model for 3 weeks. Hepatic injury, intestinal barrier, gut microbiome, and the associated fecal metabolome were then studied. Following 6 weeks of CDA-HFD, the absence of methylation-controlled J protein, an inhibitor of mitochondrial complex I activity, reduced hepatic injury and improved gut-liver axis in an aggressive NASH dietary model. This effect was transferred to GF mice through cecal microbiota transplantation. We suggest that the specific microbiota profile of MCJ-KO, characterized by an increase in the fecal relative abundance of Dorea and Oscillospira genera and a reduction in AF12, Allboaculum, and [Ruminococcus], exerted protective actions through enhancing short-chain fatty acids, nicotinamide adenine dinucleotide (NAD+) metabolism, and sirtuin activity, subsequently increasing fatty acid oxidation in GF mice. Importantly, we identified Dorea genus as one of the main modulators of this microbiota-dependent protective phenotype. Conclusions: Overall, we provide evidence for the relevance of mitochondria–microbiota interplay during NASH and that targeting it could be a valuable therapeutic approach.S
Boosting mitochondria activity by silencing MCJ overcomes cholestasis-induced liver injury
Background & Aims: Mitochondria are the major organelles for the formation of reactive oxygen species (ROS) in the cell, and mitochondrial dysfunction has been described as a key factor in the pathogenesis of cholestatic liver disease. The methylation-controlled J-protein (MCJ) is a mitochondrial protein that interacts with and represses the function of complex I of the electron transport chain. The relevance of MCJ in the pathology of cholestasis has not yet been explored. Methods: We studied the relationship between MCJ and cholestasis-induced liver injury in liver biopsies from patients with chronic cholestatic liver diseases, and in livers and primary hepatocytes obtained from WT and MCJ-KO mice. Bile duct ligation (BDL) was used as an animal model of cholestasis, and primary hepatocytes were treated with toxic doses of bile acids. We evaluated the effect of MCJ silencing for the treatment of cholestasis-induced liver injury. Results: Elevated levels of MCJ were detected in the liver tissue of patients with chronic cholestatic liver disease when compared with normal liver tissue. Likewise, in mouse models, the hepatic levels of MCJ were increased. After BDL, MCJ-KO animals showed significantly decreased inflammation and apoptosis. In an in vitro model of bile-acid induced toxicity, we observed that the loss of MCJ protected mouse primary hepatocytes from bile acid-induced mitochondrial ROS over-production and ATP depletion, enabling higher cell viability. Finally, the in vivo inhibition of the MCJ expression, following BDL, showed reduced liver injury and a mitigation of the main cholestatic characteristics. Conclusions: We demonstrated that MCJ is involved in the progression of cholestatic liver injury, and our results identified MCJ as a potential therapeutic target to mitigate the liver injury caused by cholestasis. Lay summary: In this study, we examine the effect of mitochondrial respiratory chain inhibition by MCJ on bile acid-induced liver toxicity. The loss of MCJ protects hepatocytes against apoptosis, mitochondrial ROS overproduction, and ATP depletion as a result of bile acid toxicity. Our results identify MCJ as a potential therapeutic target to mitigate liver injury in cholestatic liver diseases.Acknowledgements: We thank MINECO for the Severo Ochoa Excellence Accreditation of CIC bioGUNE [SEV-2016-0644]
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