It has been found that fat oxidation is reduced in the skeletal muscle of obese humans. This study aims to identify the mRNA of proteins involved in fat oxidation that may be reduced in obese and morbidly obese individuals. Information gathered will help in understanding how obesity contributes to cardiovascular disease via insulin resistance.
GRB14, GPD1, and GDF8 as potential network collaborators in weight loss-induced improvements in insulin action in human skeletal muscle.
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View SamplesObesity results from a chronic imbalance between energy intake and energy expenditure, with excess calories stored as fat. As such, weight loss has long been considered as a primary goal of treatment for obesity. A surgical treatment of severe obesity such as gastric bypass provides the most dramatic reductions in body weight, and a well-known effect of weight loss is an improvement in insulin sensitivity. However, the molecular mechanism underlying this association remains unclear. Thus, we profiled skeletal muscle of morbidly obese patients before and after gastric bypass surgery. Results from this project will provide global patterns of gene expression with weight loss, which help to understand the pathogenesis of obesity at the molecular level.
GRB14, GPD1, and GDF8 as potential network collaborators in weight loss-induced improvements in insulin action in human skeletal muscle.
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View SamplesWe used microarray analysis to examine which genes are differentially expressed in mice that received a combination of fish oil and indomethacin.
Fish oil and indomethacin in combination potently reduce dyslipidemia and hepatic steatosis in LDLR(-/-) mice.
Specimen part, Compound
View SamplesDiurnal temperature cycling is an intrinsic characteristic of many exposed microbial ecosystems. However, its influence on yeast physiology and transcriptome has not been studied in detail. In this study, 24-h sinoidal temperature cycles, oscillating between 12 and 30C, were imposed on anaerobic, glucose-limited chemostat cultures of Saccharomyces cerevisiae. After three diurnal temperature cycles (DTC), concentrations of glucose, and extracellular metabolites, as well as CO2-production rates showed regular, reproducible circadian rhytms. DTC also led to waves of transcriptional activation and repression, which involved one sixth of the yeast genome. A substantial fraction of these DTC-responsive genes appeared to primarily respond to changes in glucose concentration. Elimination of known glucose-responsive genes revealed overrepresentation of previously identified temperature-responsive genes as well as genes involved in cell cycle and de novo purine biosynthesis. Analyses of budding index and flow cytomery demonstrated that DTC led to a partial synchronization of the cell cycle of the yeast populations in the chemostat cultures, which was lost upon release from DTC. Comparison of DTC results with data from steady-state cultures showed that DTC was sufficiently slow to allow S. cerevisiae chemostat cultures to almost completely acclimatize their transcriptome and physiology at the DTC temperature maximum, and to approach acclimation at the DTC temperature minimum.
Physiological and transcriptional responses of anaerobic chemostat cultures of Saccharomyces cerevisiae subjected to diurnal temperature cycles.
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View SamplesThe present study aims to explore chemostat-based transcriptome analysis of mixed cultures by investigating interactions between the yeast S. cerevisiae and the lactic acid bacterium Lb. bulgaricus . S. cerevisiae and Lb. bulgaricus are both frequently encountered in kefir, a fermented dairy product (25). In the context of this study, this binary culture serves as a model for the many traditional food and beverage fermentation processes in which yeasts and lactic acid bacteria occur together (19,26-30). The design of the cultivation conditions was based on the observation that Lb. bulgaricus, but not S. cerevisiae, can use lactose as a carbon source for growth and that S. cerevisiae, but not Lb. bulgaricus, can grow on galactose that is released upon hydrolysis of lactose by the bacterial -galactosidase.
Transcriptome-based characterization of interactions between Saccharomyces cerevisiae and Lactobacillus delbrueckii subsp. bulgaricus in lactose-grown chemostat cocultures.
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View SamplesHuman aging is associated with loss of function and regenerative capacity. Human bone marrow derived mesenchymal stromal cells (hMSCs) are involved in tissue regeneration, evidenced by their capacity to differentiate into several lineages and therefore are considered the gold standard for cell-based regeneration therapy. Tissue maintenance and regeneration is dependent on stem cells and declines with age and aging is thought to influence therapeutic efficacy, therefore, more insight in the process of aging of hMSCs is of high interest. We, therefore, hypothesized that hMSCs might reflect signs of aging. In order to find markers for donor age, early passage hMSCs were isolated from bone marrow of 61 donors, with ages varying from 17-84, and clinical parameters, in vitro characteristics and microarray analysis were assessed. Although clinical parameters and in vitro performance did not yield reliable markers for aging since large donor variations were present, genome-wide microarray analysis resulted in a considerable list of genes correlating with human age. By comparing the transcriptional profile of aging in human with the one from rat, we discovered follistatin as a common marker for aging in both species. The gene signature presented here could be a useful tool for drug testing to rejuvenate hMSCs or for the selection of more potent, hMSCs for cell-based therapy.
A mesenchymal stromal cell gene signature for donor age.
Sex, Age
View SamplesZinc is indispensable for the catalytic activity and structural stability of many proteins, and its deficiency can have severe consequences for microbial growth in natural and industrial environments. For example, Zn depletion in wort negatively affects beer fermentation and quality. Several studies have investigated yeast adaptation to low Zn supply, but were all performed in batch cultures, where specific growth rate depends on Zn availability. The transcriptional responses to growth-rate and Zn availability are then intertwined, which obscures result interpretation. In the present study, transcriptional responses of Saccharomyces cerevisiae to Zn availability were investigated at a fixed specific growth rate under Zn limitation and excess in chemostat culture. To investigate the context-dependency of this transcriptional response, yeast was grown under several chemostat regimes resulting in various carbon (glucose), nitrogen (ammonium) and oxygen supplies. A robust set of genes that responded consistently to Zn limitation was identified and enabled the definition of a Zn-specific Zap1 regulon comprising of 26 genes and characterized by a broader ZRE consensus (MHHAACCBYNMRGGT) than so far described. Most surprising was the Zn-dependent regulation of genes involved in storage carbohydrate metabolism. Their concerted down-regulation was physiologically relevant as revealed by a substantial decrease in glycogen and trehalose cellular content under Zn limitation. An unexpectedly large amount of genes were synergistically or antagonistically regulated by oxygen and Zn availability. This combinatorial regulation suggested a more prominent involvement of Zn in mitochondrial biogenesis and function than hitherto identified
Physiological and transcriptional responses of Saccharomyces cerevisiae to zinc limitation in chemostat cultures.
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View SamplesZinc is indispensable for the catalytic activity and structural stability of many proteins, and its deficiency can have severe consequences for microbial growth in natural and industrial environments. For example, Zn depletion in wort negatively affects beer fermentation and quality. Several studies have investigated yeast adaptation to low Zn supply, but were all performed in batch cultures, where specific growth rate depends on Zn availability. The transcriptional responses to growth-rate and Zn availability are then intertwined, which obscures result interpretation. In the present study, transcriptional responses of Saccharomyces cerevisiae to Zn availability were investigated at a fixed specific growth rate under Zn limitation and excess in chemostat culture. To investigate the context-dependency of this transcriptional response, yeast was grown under several chemostat regimes resulting in various carbon (glucose), nitrogen (ammonium) and oxygen supplies. A robust set of genes that responded consistently to Zn limitation was identified and enabled the definition of a Zn-specific Zap1 regulon comprising of 26 genes and characterized by a broader ZRE consensus (MHHAACCBYNMRGGT) than so far described. Most surprising was the Zn-dependent regulation of genes involved in storage carbohydrate metabolism. Their concerted down-regulation was physiologically relevant as revealed by a substantial decrease in glycogen and trehalose cellular content under Zn limitation. An unexpectedly large amount of genes were synergistically or antagonistically regulated by oxygen and Zn availability. This combinatorial regulation suggested a more prominent involvement of Zn in mitochondrial biogenesis and function than hitherto identified.
Physiological and transcriptional responses of Saccharomyces cerevisiae to zinc limitation in chemostat cultures.
No sample metadata fields
View SamplesZinc is indispensable for the catalytic activity and structural stability of many proteins, and its deficiency can have severe consequences for microbial growth in natural and industrial environments. For example, Zn depletion in wort negatively affects beer fermentation and quality. Several studies have investigated yeast adaptation to low Zn supply, but were all performed in batch cultures, where specific growth rate depends on Zn availability. The transcriptional responses to growth-rate and Zn availability are then intertwined, which obscures result interpretation. In the present study, transcriptional responses of Saccharomyces cerevisiae to Zn availability were investigated at a fixed specific growth rate under Zn limitation and excess in chemostat culture. To investigate the context-dependency of this transcriptional response, yeast was grown under several chemostat regimes resulting in various carbon (glucose), nitrogen (ammonium) and oxygen supplies. A robust set of genes that responded consistently to Zn limitation was identified and enabled the definition of a Zn-specific Zap1 regulon comprising of 26 genes and characterized by a broader ZRE consensus (MHHAACCBYNMRGGT) than so far described. Most surprising was the Zn-dependent regulation of genes involved in storage carbohydrate metabolism. Their concerted down-regulation was physiologically relevant as revealed by a substantial decrease in glycogen and trehalose cellular content under Zn limitation. An unexpectedly large amount of genes were synergistically or antagonistically regulated by oxygen and Zn availability. This combinatorial regulation suggested a more prominent involvement of Zn in mitochondrial biogenesis and function than hitherto identified
Physiological and transcriptional responses of Saccharomyces cerevisiae to zinc limitation in chemostat cultures.
No sample metadata fields
View SamplesAnalysis of p53 binding sites using multiplex enhancer reporter assays, ChIP-seq data and RNA-seq data. Transcription factors establish and maintain the specific transcriptome of a cell by binding to genomic regulatory regions, thereby regulating the transcription of their target genes. Like many transcription factors, the DNA sequence-specific binding preferences of p53 are known. However, it remains largely unclear what distinguishes functional enhancers from other bound genomic regions that have no regulatory activity. In addition, the genome is scattered with seemingly perfect recognition sequences that remain unoccupied. To disentangle the rules of genome-wide p53 binding, we employed two complementary techniques of multiplex enhancer-reporter assays, one using barcoded reporters and the other using enhancer self-transcription. We compared the activity of more than one thousand candidate p53 enhancers under loss and gain of p53 conditions and identified several hundred high-confidence p53-responsive enhancers. Strikingly, the large majority (99%) of these target enhancers can be characterized and distinguished from negative sequences by the occurrence of a single p53 binding site. By training a machine learning classifier on these data, and integrating the resulting genome-wide predictions with fifteen publicly available human p53 ChIP-seq data sets, we identified a consensus set of 1148 functional p53 binding sites in the human genome. Unexpectedly, this direct p53 cistrome is invariably used between cell types and experimental conditions, while differences between experiments can be largely attributed to indirect non-functional binding. Our data suggest that direct p53 enhancers function in a context-independent manner and do not contain obvious combinatorial complexity of binding sites for multiple transcription factors. They represent a class of unsophisticated cell-autonomous enhancers with a single binding site, distinct from complex developmental enhancers that integrate signals from multiple transcription factors. This suggests that context-dependent regulation of p53 target genes is not encoded in the p53 enhancer, but at different upstream or downstream layers of the cell''s gene regulatory network. Overall design: RNA-seq on MCF7 cells with p53 stable knockdown.
Multiplex enhancer-reporter assays uncover unsophisticated TP53 enhancer logic.
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