Skeletal muscle has been identified as a secretory organ. We hypothesized that IL-6, a cytokine secreted from skeletal muscle during exercise, could induce production of other secreted factors in skeletal muscle.
Calprotectin is released from human skeletal muscle tissue during exercise.
Sex, Subject, Time
View SamplesSkeletal muscle of insulin resistant individuals is characterized by lower fasting lipid oxidation and reduced ability to switch between lipid and glucose oxidation. The purpose of the present study was to examine if impaired metabolic switching could be induced by chronic hyperglycemia. Human myotubes were treated with or without chronic hyperglycemia (HG) (20 mmol/l glucose for 4 days), and the metabolism of [14C]oleic acid (OA) and [14C]glucose was studied. Acute glucose (5mmol/l) suppressed OA oxidation by 50% in normoglycemic (NG) (5.5 mmol/l glucose) cells. Myotubes exposed to chronic hyperglycemia showed a significantly reduced OA uptake and oxidation to CO2, whereas acid-soluble metabolites were increased. Glucose suppressibility, the ability of acute glucose to suppress lipid oxidation, was significantly reduced to 21%, while adaptability, the capacity to increase lipid oxidation with increasing fatty acid availability, was unaffected. Glucose uptake and oxidation was significantly reduced by about 40%. Substrate oxidation in presence of mitochondrial uncouplers showed that net and maximal oxidative capacities were significantly reduced after hyperglycemia, and the concentration of ATP was reduced by 25%. However, none of the measured mitochondrial genes were downregulated nor was mitochondrial content. Microarray showed that no genes were significantly regulated by chronic hyperglycemia. Addition of chronic lactate reduced both glucose and OA oxidation to the same extent as hyperglycemia, and this effect was specific for lactate. In conclusions, chronic hyperglycemia reduced substrate oxidation in skeletal muscle cells and impaired the metabolic switching. The effect is most likely due to an induced mitochondrial dysfunction.
Chronic hyperglycemia reduces substrate oxidation and impairs metabolic switching of human myotubes.
Specimen part
View SamplesThe aim of the present work was to study the effects of benfotiamine (S-benzoylthiamine O-monophosphate) upon glucose and lipid metabolism and gene expression in differentiated human skeletal muscle cells (myotubes) incubated for 4 days under normal (5.5 mM glucose) and hyperglycemic (20 mM glucose) conditions.
Benfotiamine increases glucose oxidation and downregulates NADPH oxidase 4 expression in cultured human myotubes exposed to both normal and high glucose concentrations.
Specimen part, Subject
View SamplesWe performed a polysomal RNA-Seq screen in non-malignant breast epithelial (MCF10A) and TNBC (MDA-MB-231) cells exposed to normoxic or hypoxic conditions and/or treated with an mTOR pathway inhibitor. Analysis of both the transcriptome and the translatome identified mRNA transcripts translationally activated or repressed by hypoxia in an mTOR-dependent or -independent manner. The mRNA populations of each sample were converted to cDNA libraries using the TruSeq protocol and then sequenced using a HiSeq 2000 machine. Paired-end reads were mapped against the reference human genome (GRCh38) with STAR v2.5.1b (ENCODE parameters for long RNA) and GENCODE v24 annotation. Gene quantification was performed using RSEM v1.2.28 with default parameters. Only protein-coding genes were included in the analysis. Normalization of the count matrix was performed with the TMM method of the edgeR R package. Polysomal RNA (P) and RNA total (T) fold changes across conditions were calculated with edgeR. Significant genes (FDR < 5% for MCF10A cells and FDR < 10% for MDA-MB-231 cells) in polysomes were selected for translational efficiency calculation (log2FC RNA polysomes/log2FC RNA total). Genes with a z-score > 1.5 were considered to have an increased translational efficiency and genes with a z-score < –1.5 were considered to have a decreased translational efficiency. GO enrichment analysis of significant genes was performed with the DAVID database. Overall design: RNA-Seq profiles in polysomes vs total in Normoxia, Hypoxia, Hypoxia + PP242, Normoxia + PP242 in MCF10A and MDA-MB-231 cell lines
Hypoxia-mediated translational activation of ITGB3 in breast cancer cells enhances TGF-β signaling and malignant features <i>in vitro</i> and <i>in vivo</i>.
Cell line, Treatment, Subject
View SamplesHaCat cell cycle experiment: During the somatic cell cycle, DNA and epigenetic modifications in DNA and histones are copied to daughter cells. DNA replication timing is tightly regulated and linked to GC content, chromatin structure, andgene transcription, but how maintenance of histone modifications relates to replication timing and transcription is less understood.The gene expression patters on HaCaT keratinocytes during the cell cycle is studied by a time series analysis of synchroniced cells sampled at 3 hour intervals. We show that genes enriched with the repressive chromatin mark histone H3 lysine 27 tri-methylation are transcribed during DNA replication . The gene expression is related to replication timing, as genes expressed during G1/S transition andearly S phase generally have higher GC content and are replicated earlier than genes expressed during late S phase. These results indicate widespread replication-dependent expression in mammals and support a role for replication in transiently activating transcription of epigenetically silenced genes.
Transcription profiling during the cell cycle shows that a subset of Polycomb-targeted genes is upregulated during DNA replication.
Specimen part, Cell line, Time
View SamplesThe generation of induced pluripotent stem (iPS) cells 1-4 has spawned unprecedented opportunities for investigating the molecular logic that underlies cellular pluripotency and reprogramming, as well as for obtaining patient-specific cells for future clinical applications. However, both prospects are hampered by the low efficiency of the reprogramming process. Here, we show that juvenile human primary keratinocytes can be efficiently reprogrammed to pluripotency by retroviral transduction with Oct4, Sox2, Klf4 and c-Myc. Keratinocyte-derived iPS (KiPS) cells appear indistinguishable from human embryonic stem (hES) cells in colony morphology, growth properties, expression of pluripotency-associated transcription factors and surface markers, as well as in vitro and in vivo differentiation potential. Notably, keratinocyte reprogramming to pluripotency is, at least, 100-fold more efficient and 2-fold faster than that of fibroblasts. This increase in reprogramming efficiency allowed us to expand the practicability of the technology and to generate KiPS cells from single plucked hairs from adult individuals.
Efficient and rapid generation of induced pluripotent stem cells from human keratinocytes.
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View SamplesInduced pluripotent stem (iPS) cells have generated interest for regenerative medicine as they allow for producing patient-specific progenitors in vitro with potential value for cell therapy. In many instances, however, an off-the-shelf approach would be desirable, such as for cell therapy of acute conditions or when the patient's somatic cells are altered as a consequence of chronic disease or aging. Cord blood (CB) stem cells appear ideally suited for this purpose as they are newborn, immunologically immature cells with minimal genetic and epigenetic alterations, and several hundred thousand immunotyped CB units are readily available through a worldwide network of CB banks. Here, we show that CB stem cells can be reprogrammed to pluripotency by retroviral transduction with OCT4, SOX2, KLF4, and c-MYC, in a process that is extremely efficient and fast. The resulting CB-derived iPS (CBiPS) cells are phenotypically and molecularly indistinguishable from human embryonic stem (hES) cells. Furthermore, we show that generation of CBiPS can be efficiently achieved without the use of the c-MYC and KLF4 oncogenes and just by overexpression of OCT4 and SOX2. Our studies set the basis for the creation of a comprehensive bank of HLA-matched CBiPS cells for off-the-shelf applications.
Generation of induced pluripotent stem cells from human cord blood using OCT4 and SOX2.
Specimen part
View SamplesWe used microarray-based expression genomics in 25 inbred mouse strains to identify dorsal root ganglion (DRG)-expressed genetic contributors to mechanical allodynia a prominent symptom of chronic pain.
The nicotinic α6 subunit gene determines variability in chronic pain sensitivity via cross-inhibition of P2X2/3 receptors.
Sex, Age, Specimen part
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