Understanding the transcriptional regulation of pluripotent cells is of fundamental interest and will greatly inform efforts aimed at directing differentiation of embryonic stem (ES) cells or reprogramming somatic cells. We first analyzed the transcriptional profiles of mouse ES cells and primordial germ cell (PGCs) and identified genes up-regulated in pluripotent cells both in vitro and in vivo. These genes are enriched for roles in transcription, chromatin remodeling, cell cycle and DNA repair. We developed a novel computational algorithm, CompMoby, which combines analyses of sequences both aligned and non-aligned between different genomes with a probabilistic segmentation model to systematically predict short DNA motifs that regulate gene expression. CompMoby was used to identify conserved over-represented motifs in genes up-regulated in pluripotent cells. We show that the motifs are preferentially active in undifferentiated mouse ES and Embryonic Germ cells in a sequence-specific manner, and that they can act as enhancers in the context of an endogenous promoter. Importantly, the activity of the motifs is conserved in human ES cells. We further show that the transcription factor NF-Y specifically binds to one of the motifs, is differentially expressed during ES cell differentiation and is required for ES cell proliferation. This study provides novel insights into the transcriptional regulatory networks of pluripotent cells. Our results suggest that this systematic approach can be broadly applied to understanding transcriptional networks in mammalian species.
Systematic identification of cis-regulatory sequences active in mouse and human embryonic stem cells.
Age, Specimen part, Time
View SamplesThis is polyA mRNA-seq of a clonal MIN6 beta cell line that expresses EGFP under the control of the insulin promoter and mCherry under control of the RSV promoter.
No associated publication
Sex, Specimen part
View SamplesInsulin resistance in skeletal muscle is a key phenotype associated with type 2 diabetes (T2D) and is even present in offspring of diabetic parents. However, molecular mediators of insulin resistance remain unclear. We find that the top-ranking gene set in expression analysis of muscle from humans with T2D and normoglycemic insulin resistant subjects with parental family history (FH+) of T2D is increased expression of actin cytoskeleton genes regulated by serum response factor (SRF) and its coactivator MKL1. Furthermore, the SRF activator STARS is upregulated in FH+ and T2D and inversely correlated with insulin sensitivity. These patterns are recapitulated in insulin resistant mice, and linked to alterations in two other regulators of this pathway: reduced G-actin and increased nuclear localization of MKL1. Both genetic and pharmacologic manipulation of STARS/MKL1/SRF pathway significantly alter insulin action: 1) Overexpression of MKL1 or reduction in G-actin decreased insulin-stimulated Akt phosphorylation; 2) reduced STARS expression increased insulin signalling and glucose uptake, and 3) SRF inhibition by CCG-1423 reduced nuclear MKL1, improved glucose uptake, and improved glucose tolerance in insulin resistant mice in vivo. Thus, SRF pathway alterations are a signature of insulin resistance which may also contribute to T2D pathogenesis and be a novel therapeutic target.
Increased SRF transcriptional activity in human and mouse skeletal muscle is a signature of insulin resistance.
Sex, Age, Specimen part
View SamplesCytokine-induced signal transduction is executed by natural biological switches, which among many others control immune related processes. To construct a biological device, that simulates cytokine signaling, we utilized nanobodies to generate synthetic cytokine receptors (SyCyR). High affinity GFP- and mCherry-nanobodies were selected and extracellularly fused to trans-membrane and intracellular domains of IL-23 cytokine receptors. Soluble homo- and heterodimeric GFP:mCherry fusion proteins served as SyCyR ligands. Heterodimeric GFP-mCherry and homodimeric GFP fusion proteins efficiently phenocopied IL-23 signal transduction, respectively, as demonstrated by STAT3-, ERK- and Akt-activation, SOCS3 expression and transcriptome profiling. Interestingly, the homodimeric GFP fusion protein induced IL-23 receptor homo-dimerization and activation of IL-23-like signal transduction
Synthetic cytokine receptors transmit biological signals using artificial ligands.
Specimen part, Cell line
View SamplesCytokine signaling is transmitted by cell surface receptors which function as natural biological switches to control among others mainly immune related processes. Recently, we have designed synthetic cytokine receptors (SyCyRs) consisting of GFP- and mCherry-nanobodies fused to trans-membrane and intracellular domains of cytokine receptors, which phenocopied cytokine signaling induced by non-physiological homo- and heterodimeric GFP-mCherry ligands. Interleukin 22 signals via IL-22Rα1 and the common IL-10R2, belongs to the IL-10 cytokine family and is critically involved in tissue regeneration. IL-22 SyCyRs phenocopied native IL-22 signal transduction as shown by induction of cytokine-dependent cellular proliferation, signal transduction and transcriptome analysis. Whereas homodimeric IL-22Rα1 SyCyRs failed to activate signaling, homodimerization of the second IL-22 signaling chain, SyCyR(IL-10R2), which was considered to not induce signal transduction, lead to induction of signal transduction. Interestingly, the SyCyR(IL-10R2) and SyCyR(IL-22Rα1) were able to form functional heterodimeric receptor signaling complexes with the synthetic IL-6 receptor chain SyCyR(gp130). In summary, we demonstrated that IL-22 signaling can be phenocopied by synthetic cytokine receptors. Further we identified a novel IL-10R2 homodimeric receptor complex and receptor cross-talk with gp130.
Synthetic interleukin 22 (IL-22) signaling reveals biological activity of homodimeric IL-10 receptor 2 and functional cross-talk with the IL-6 receptor gp130.
Specimen part, Treatment
View SamplesDespite a high degree of homology, insulin and IGF-1 receptors (IR/IGF1R) mediate distinct cellular and physiological functions. Here, using chimeric and site-mutated receptors, we demonstrate how domain differences between IR and IGF1R contribute the distinct functions of these receptors.
No associated publication
Specimen part, Treatment
View SamplesThe key lipid metabolism transcription factor sterol regulatory element-binding protein (SREBP)-1a integrates gene regulatory effects of hormones, cytokines, nutrition and metabolites as lipids, glucose or cholesterol via stimuli specific phosphorylation by different MAPK cascades. We have formerly reported the systemic impact of phosphorylation in transgenic mouse models with liver-specific overexpression of the N-terminal transcriptional active domain of SREBP-1a (alb-SREBP-1a) or a MAPK kinase phosphorylation sites deficient variant (alb-SREBP-1aP; (S63A, S117A, T426V)), respectively. Here we investigated the molecular basis of the systemic observation in holistic hepatic gene expression analyses and lipid degrading organelles involved in the pathogenesis of metabolic syndrome, i.e. peroxisomes, by 2D-DIGE and mass spectrometry analyses. Although alb-SREBP-1a mice develop a severe phenotype with visceral adipositas and hepatic lipid accumulation featuring a fatty liver, the hepatic differential gene expression and alterations in peroxisomal protein patterns compared to control mice were surprisingly relative low. In contrast, phosphorylation site deficient alb-SREBP-1aP mice, protected from hepatic lipid accumulation phenotype, showed gross alteration in hepatic gene expression and peroxisomal proteome. Further knowledge based analyzes revealed that overexpression of SREBP-1a favored mainly acceleration in lipid metabolism and indicated a regular insulin signaling, whereas disruption of SREBP-1a phosphorylation resulted in massive alteration of cellular processes including signs for loss of lipid metabolic targets. These results could be the link to a disturbed lipid metabolism that overall resembles a state of insulin resistance.
Inactivation of SREBP-1a Phosphorylation Prevents Fatty Liver Disease in Mice: Identification of Related Signaling Pathways by Gene Expression Profiles in Liver and Proteomes of Peroxisomes.
Sex, Age, Specimen part
View SamplesWe and others have previously observed that adipocytes and preadipocytes taken from different adipose tissue depots are characterized by differential expression of developmental and patterning genes (Dankel et al., 2010; Ferrer-Lorente et al., 2014; Gesta et al., 2006; Lee et al., 2017a; Lee et al., 2013; Macotela et al., 2012; Tchkonia et al., 2007; Yamamoto et al., 2010). To investigate how adipocyte heterogeneity and differences in the expression of developmental genes might impact the biology of adipocytes and preadipocytes, we created preadipocyte cell lines from the stromovascular fraction (SVF) isolated from the scapular white, inguinal, perigonadal, perirenal, and mesenteric fat pads of 6-week old male Immortomouse (Jat et al., 1991).During routine culture of the subcutaneous and visceral/perigonadal clonal cell lines, we observed extreme variation in media acidification rates that was unrelated to the fat pad of origin, the differentiation capacity of the cells, or the rate of their proliferation, suggesting metabolic heterogeneity. To further investigate this possibility, 24 clonal cell lines (12 each from subcutaneous and perigonadal fat) were selected based on variable media acidification rates, and their mRNA expression pattern determined by microarray analysis. The expression data was clustered using three different algorythms, and the consensus was used to categorize each type of adipose tissue.
Developmental and functional heterogeneity of white adipocytes within a single fat depot.
Specimen part, Cell line
View SamplesHepatic lipid accumulation is an important complication of obesity linked to risk for type 2 diabetes. To identify novel transcriptional changes in human liver which could contribute to hepatic lipid accumulation and associated insulin resistance and type 2 diabetes (DM2), we evaluated gene expression and gene set enrichment in surgical liver biopsies from 13 obese (9 with DM2) and 5 control subjects, obtained in the fasting state at the time of elective abdominal surgery for obesity or cholecystectomy. RNA was isolated for cRNA preparation and hybridized to Affymetrix U133A microarrays.
Thyroid hormone-related regulation of gene expression in human fatty liver.
Sex, Age
View SamplesAlternative mRNA splicing provides transcript diversity and has been proposed to contribute to several human diseases. Here, we demonstrate that expression of genes regulating RNA processing is decreased in both liver and skeletal muscle of obese humans. To determine the metabolic impact of reduced splicing factor expression, we further evaluated the splicing factor, SFRS10, identified as down-regulated in obese human liver and skeletal muscle and in high fat fed rodents. siRNA-mediated reductions in SFRS10 expression induced lipogenesis and lipid accumulation in cultured hepatocytes. Moreover, SFRS10 heterozygous mice have both increased hepatic lipogenic gene expression and hypertriglyceridemia. We also demonstrate that LPIN1, a key regulator of lipid metabolism, is a splicing target of SFRS10, with reduced SFRS10 levels favoring the lipogenic isoform of LPIN1. Importantly, LPIN1-specific siRNA abolished the lipogenic effects of decreased SFRS10 expression. Together, our results indicate reduced expression of SFRS10 alters LPIN1 splicing and induces lipogenesis, demonstrating that reduced splicing factor expression observed in human tissues may contribute to metabolic phenotypes associated with human obesity.
Expression of the splicing factor gene SFRS10 is reduced in human obesity and contributes to enhanced lipogenesis.
Age, Subject
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