This SuperSeries is composed of the SubSeries listed below.
VEGF-B signaling impairs endothelial glucose transcytosis by decreasing membrane cholesterol content.
Age, Specimen part, Cell line, Treatment
View SamplesRegulation of endothelial nutrient transport is poorly understood. Vascular endothelial growth factor (VEGF)-B signaling in endothelial cells promotes uptake and transcytosis of fatty acids (FA) from the bloodstream to the underlying tissue, advancing pathological lipid accumulation and lipotoxicity in diabetic complications. Here we demonstrate a VEGF-B dependent obstruction of endothelial glucose transport attributed to plasma membrane lipid alterations affecting glucose transporter 1 function, which was independent of FA uptake. Specifically, VEGF-B signaling impaired recycling of low-density lipoprotein receptor to the plasma membrane, leading to reduced cholesterol uptake and membrane cholesterol loading, decreasing endothelial glucose uptake capacity. Inhibiting VEGF-B in vivo was accordingly linked to reconstitution of membrane cholesterol and induction of glucose uptake, of particular relevance for conditions inferring insulin resistance and diabetic complications. In summary, our study reveals a novel mechanism of action for VEGF-B in endothelial nutrient uptake and highlights the impact of membrane cholesterol for the regulation of endothelial glucose transport.
VEGF-B signaling impairs endothelial glucose transcytosis by decreasing membrane cholesterol content.
Specimen part, Cell line, Treatment
View SamplesRegulation of endothelial nutrient transport is poorly understood. Vascular endothelial growth factor (VEGF)-B signaling in endothelial cells promotes uptake and transcytosis of fatty acids (FA) from the bloodstream to the underlying tissue, advancing pathological lipid accumulation and lipotoxicity in diabetic complications. Here we demonstrate a VEGF-B dependent obstruction of endothelial glucose transport attributed to plasma membrane lipid alterations affecting glucose transporter 1 function, which was independent of FA uptake. Specifically, VEGF-B signaling impaired recycling of low-density lipoprotein receptor to the plasma membrane, leading to reduced cholesterol uptake and membrane cholesterol loading, decreasing endothelial glucose uptake capacity. Inhibiting VEGF-B in vivo was accordingly linked to reconstitution of membrane cholesterol and induction of glucose uptake, of particular relevance for conditions inferring insulin resistance and diabetic complications. In summary, our study reveals a novel mechanism of action for VEGF-B in endothelial nutrient uptake and highlights the impact of membrane cholesterol for the regulation of endothelial glucose transport.
VEGF-B signaling impairs endothelial glucose transcytosis by decreasing membrane cholesterol content.
Age, Specimen part
View SamplesBackground: Interaction between key signaling mechanisms is important to generate the diversity in signaling output required for proper control of cellular differentiation and function, although the molecular manifestations of such cross-talk are only partially understood. Notch signaling and the cellular response to hypoxia intersect at different points in the signaling cascades, and in this report we analyze the consequences of this cross-talk at the transcriptome level. Results: Mouse ES cells were subjected to various combinations of hypoxia and/or activated Notch signaling, and the transcriptome changes could be grouped into different categories, reflecting various modes of hypoxia and Notch signaling integration. Two principal categories of novel Notch- and hypoxia-induced genes were identified: i) a larger set of genes induced by one pathway and not significantly affected by the activity status of the other pathway; and ii) a smaller set of genes co-regulated by Notch and hypoxia. In the latter category, we identified genes that were induced by hypoxia and the expression of which was enhanced by active Notch signaling. In addition, a number of genes were induced by Notch and hypoxia independently, and a final category of genes required simultaneous activation of Notch and hypoxia to be significantly induced. Several of the hypoxia- and Notch-induced genes were found to be upregulated in various forms of cancer. Conclusions: We identify novel Notch and hypoxia downstream genes and genes co-regulated by the two pathways, providing a molecular platform to better understand the intersection between the two signaling cascades in normal development and cancer.
Interactions between Notch- and hypoxia-induced transcriptomes in embryonic stem cells.
Sex, Specimen part, Treatment
View SamplesHyperactivation of Notch signaling and the cellular hypoxic response are frequently observed in cancers, with increasing reports of connections to tumor initiation and progression. The two signaling mechanisms are known to intersect, but while it is well established that hypoxia regulates Notch signaling, less is known about whether Notch can regulate the cellular hypoxic response. We now report that Notch signaling specifically controls expression of HIF2a, a key mediator of the cellular hypoxic response. Transcriptional upregulation of HIF2a by Notch under normoxic conditions leads to elevated HIF2a protein levels in primary breast cancer cells as well as in human breast cancer, medulloblastoma and renal cell carcinoma cell lines. The elevated level of HIF2a protein was in certain tumor cell types accompanied by down-regulation of HIF1a protein levels, indicating that high Notch signaling may drive a HIF1a-to-HIF2a switch. At the transcriptome level, the presence of HIF2a was required for approximately 21% of all Notch-induced genes: among the 1062 genes that were upregulated by Notch in medulloblastoma cells during normoxia, upregulation was abrogated in 227 genes when HIF2a expression was knocked down by HIF2a siRNA. In conclusion, our data show that Notch signaling affects the hypoxic response via regulation of HIF2a, which may be important for future cancer therapies. Overall design: DAOY-NERT2 cells, +/- Notch induction by Tamoxifen (TMX) for 48 hours, +/- hypoxia (1% O2) treatment for 48 hours, where HIF1a or HIF2a had been knocked down by siRNA, were subjected to RNA sequencing. The quality of the cDNA libraries was tested on an Agilent 2100 bioanalyzer. The libraries were sequenced on an Illumina HiSeq 2000 system, and the reads were aligned to the human genome (assembly hg19) and a transcriptome database (RefSeq and Ensembl) using bowtie. RPKM values were generated using rpkmforgenes.
Notch signaling promotes a HIF2α-driven hypoxic response in multiple tumor cell types.
Specimen part, Subject
View SamplesNotch signaling is an important regulator of stem cell differentiation. All canonical Notch signaling is transmitted through the DNA-binding protein CSL and hyperactivated Notch signaling is associated with tumor development; thus it may be anticipated that CSL deficiency should reduce tumor growth. In contrast, we report that genetic removal of CSL in breast tumor cells caused accelerated growth of xenografted tumors. Loss of CSL unleashed a hypoxic response during normoxic conditions, manifested by stabilization of the HIF1± protein and acquisition of a polyploid giant-cell, cancer stem cell-like, phenotype. At the transcriptome level, loss of CSL upregulated more than 1750 genes and less than 3% of those genes were part of the Notch transcriptional signature. Collectively, this suggests that CSL exerts functions beyond serving as the central node in the Notch signaling cascade and reveals a novel role for CSL in tumorigenesis and regulation of the cellular hypoxic response. Overall design: CSL +/+ and CSL -/- MDA-MB-231 were subjected to Notch activation/inhibition and xenograft experiment. Total RNA were extracted from the samples and sent to NGS. Single Cell RNA-sequencing was also performed from cells isolated from xenograft tumors.
Loss of CSL Unlocks a Hypoxic Response and Enhanced Tumor Growth Potential in Breast Cancer Cells.
No sample metadata fields
View SamplesType I interferons (IFN) are important components of the innate antiviral response. A key signalling pathway activated by IFNa is the Janus kinase signal transducer and activator of transcription (JAKSTAT) pathway. Major components of the pathway have been identified. However, critical kinetic properties that facilitate accelerated initiation of intracellular antiviral signalling and thereby promote virus elimination remain to be determined. By combining mathematical modelling with experimental analysis, we show that control of dynamic behaviour is not distributed among several pathway components but can be primarily attributed to interferon regulatory factor 9 (IRF9), constituting a positive feedback loop. Model simulations revealed that increasing the initial IRF9 concentration reduced the time to peak, increased the amplitude and enhanced termina- tion of pathway activation. These model predictions were experimentally verified by IRF9 over-expression studies. Furthermore, acceleration of signal processing was linked to more rapid and enhanced expression of IFNa target genes. Thus, the amount of cellular IRF9 is a crucial determinant for amplification of early dynamics of IFNa-mediated signal transduction.
Combining theoretical analysis and experimental data generation reveals IRF9 as a crucial factor for accelerating interferon α-induced early antiviral signalling.
Specimen part, Disease, Cell line, Time
View SamplesLeukemia Inhibitory Factor is an important cytokine of the IL family. Recent findings suggest it has a crucial role in cancer progression
Leukemia Inhibitory Factor Promotes Aggressiveness of Chordoma.
Cell line
View SamplesAlthough the locations of promoters and enhancers have been identified in several cell types, we have yet limited information on their connectivity. We developed HiCap, which combines Hi-C with promoter sequence capture, to enable genome-wide identification of regulatory interactions with single-enhancer resolution. HiCap analyses of mouse embryonic stem cells (mESC) identified promoter-enhancer interactions predictive of gene expression change upon perturbation, opening up for genomic analyses of long-range gene regulation. Overall design: HiCap was designed by combining Hi-C with with sequence capture (for all promoters) and carried out in mouse embryonic stem cells (mESC)
Genome-wide mapping of promoter-anchored interactions with close to single-enhancer resolution.
No sample metadata fields
View SamplesA study on the effects of an sdiA mutant and the AHL molecule on the virulence of EHEC
Chemical sensing in mammalian host-bacterial commensal associations.
No sample metadata fields
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