Skeletal muscle is one of the primary tissues involved in the development of type 2 diabetes (T2D). Obesity is tightly associated with T2D, making it challenging to isolate specific effects attributed to the disease alone. By using an in vitro myocyte model system we were able to isolate the inherent properties retained in myocytes originating from donor muscle precursor cells, without being confounded by varying extracellular factors present in the in vivo environment of the donor. We generated and characterized transcriptional profiles of myocytes from 24 human subjects, using a factorial design with two levels each of the factors T2D (healthy or diseased) and obesity (non-obese or obese), and determined the influence of each specific factor on genome-wide transcription. We identified a striking similarity of the transcriptional profiles associated independently with T2D or obesity. Obesity thus presents an inherent phenotype in skeletal myocytes, similar to that induced by T2D. Through bioinformatics analysis we found a candidate epigenetic mechanism, H3K27me3 histone methylation, mediating the observed transcriptional signatures. Functional characterization of the expression profiles revealed dysregulated myogenesis and down-regulated muscle function in connection with T2D and obesity, as well as up-regulation of genes involved in inflammation and the extracellular matrix. Further on, we identified a metabolite subnetwork involved in sphingolipid metabolism and affected by transcriptional up-regulation in T2D. Collectively, these findings pinpoint transcriptional changes that are hard-wired in skeletal myocytes in connection with both obesity and T2D. Overall design: Isolated skeletal muscle precursor cells from 24 males and females (6 normal glucose tolerant, 6 obese, 6 type 2 diabetic, and 6 obese and type 2 diabetic) were differentiated in vitro and stimulated with insulin. RNA from fully differentiated myotubes sampled at 0, 0.5, 1, and 2 hours after insulin stimulation was quantified using RNA-seq (96 samples in total). The 6 base-line (0h) samples from normal glucose tolerant individuals are available under the submission GSE63887, the remaining 90 samples are contained in this submission.
Type 2 diabetes and obesity induce similar transcriptional reprogramming in human myocytes.
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View SamplesSkeletal myocytes are metabolically active and susceptible to insulin resistance, thus implicated in type 2 diabetes (T2D). This complex disease involves systemic metabolic changes and their elucidation at the systems level requires genome-wide data and biological networks. Genome-scale metabolic models (GEMs) provide a network-context to integrate high-throughput data. We generated myocyte-specific RNA-seq data and investigated their correlation with proteome data. These data were then used to reconstruct a comprehensive myocyte GEM. Next, we performed a meta-analysis of six studies comparing muscle transcription in T2D versus healthy subjects. Transcriptional changes were mapped on the myocyte GEM, revealing extensive transcriptional regulation in T2D, particularly around pyruvate oxidation, branched-chain amino acid catabolism, and tetrahydrofolate metabolism, connected through the down-regulated dihydrolipoamide dehydrogenase. Strikingly, the gene signature underlying this metabolic regulation successfully classifies the disease state of individual samples, suggesting that regulation of these pathways is a ubiquitous feature of myocytes in response to T2D. Overall design: Isolated skeletal muscle precursor cells from six normal glucose tolerant and non-obese males and females were differentiated in vitro. RNA from fully differentiated myotubes was sequenced using RNA-seq.
Type 2 diabetes and obesity induce similar transcriptional reprogramming in human myocytes.
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View SamplesDietary polyunsaturated fatty acids (PUFA) are suggested to modulate immune function, but the effects of dietary fatty acids composition on gene expression patterns in immune organs have not been fully characterized. In the current study we investigated how dietary fatty acids composition affects the total transcriptome profile, and especially, immune related genes, in bone marrow cells (BMC) and spleen (SPL). Four tissues with metabolic function, skeletal muscle (SKM), white adipose tissue (WAT), brown adipose tissue (BAT), and liver (LIV), were investigated as a comparison. Following 8 weeks on low fat diet (LFD), high fat diet (HFD) rich in saturated fatty acids (HFD-S), or HFD rich in PUFA (HFD-P), tissue transcriptomics were analyzed by microarray and metabolic health assessed by fasting blood glucose level, HOMA-IR index, oral glucose tolerance test as well as quantification of crown-like structures in WAT. Interestingly, SKM and BMC were relatively inert to the diets, whereas the two adipose tissues (WAT and BAT) were mainly affected by HFD per se (both HFD-S and HFD-P). In particular, WAT gene expression was driven closer to that of the immune organs SPL and BMC by HFDs. Remarkably, the spleen, showed a major response to HFD-P, but not to HFD-S, whereas the LIV exhibited different responses to both of the HFDs. Further, HFD-P corrected the metabolic phenotype induced by HFD-S. Hence, the quantity and composition of dietary fatty acids affected the transcriptome in a distinct manner. Especially, PUFA prompted a specific regulation of immune related genes in the spleen. Thus, PUFA can regulate immune function by influencing gene expression.
Six Tissue Transcriptomics Reveals Specific Immune Suppression in Spleen by Dietary Polyunsaturated Fatty Acids.
Sex, Specimen part
View SamplesIn order to elucidate the developmental origin of oligodendrocyte precursor cells (OPCs) and get a better understanding of the several waves of OPC generation, we look at several timepoints and perform single-cell RNA-seq on Pdgfra positive populations in Mice. Overall design: Mice line used in this study included Pdgfra-cre-ERT/RCE and the Pdgfra-H2BGFP knock-in mouse. Embryos at embryonic day 13.5 and pups from post-natal day 7, from both genders of the Pdgfra-GFP mice line were used to extract OPCs, as well as E12.5 and P3 tamoxifen injected mice harvested at P7. The single cell suspension from embryonic and post-natal tissue was FACS sorted for GFP positive cells using a BD FACSAria III Cell Sorter B5/R3/V3 system.
Transcriptional Convergence of Oligodendrocyte Lineage Progenitors during Development.
Cell line, Subject
View SamplesINTRODUCTION:
Increased placental expression and maternal serum levels of apoptosis-inducing TRAIL in recurrent miscarriage.
Specimen part
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