In this study, we take advantage of human induced pluripotent stem (iPS) cell-derived neural stem cells to study the role of p53 during human brain development. We knocked down (KD) p53 in human neuroepithelial stem (NES) cells derived from iPS cells. Upon p53KD, NES cells rapidly show centrosome amplification and genomic instability. Gene expression analysis show downregulation of genes involved in oxidative phosphorylation (OXPHOS) upon loss of p53. In addition, p53KD neural stem cells upregulate genes involved in neuronal differentiation and display an increased pace of differentiating into neurons and exhibit a phenotype corresponding to more mature neurons compared to control neurons. Taken together, this demonstrates an important role for p53 in controlling genomic stability of neural stem cells and regulation of neuronal differentiation.
p53 controls genomic stability and temporal differentiation of human neural stem cells and affects neural organization in human brain organoids.
Specimen part
View SamplesPreviously, it has been demonstrated that formate can be utilized by Saccharomyces cerevisiae as additional energy source using cells grown in a glucose-limited chemostat. Here, we investigated utilization of formaldehyde as co-substrate. Since endogenous formaldehyde dehydrogenase activities were insufficient to allow co-feeding of formaldehyde, the Hansenula polymorpha FLD1, encoding formaldehyde dehydrogenase, was introduced in S. cerevisiae. Chemostat cultivations revealed that formaldehyde was co-utilized with glucose, but the yield was lower than predicted. Moreover, formate was secreted by the cells. Upon co-expression of the H. polymorpha gene encoding formate dehydrogenase, FMD, the levels of secreted formate decreased, but the biomass yield was still lower than anticipated.
Engineering and analysis of a Saccharomyces cerevisiae strain that uses formaldehyde as an auxiliary substrate.
No sample metadata fields
View SamplesGenetic studies in T-cell acute lymphoblastic leukemia have uncovered a remarkable complexity of oncogenic and loss-of-function mutations. Amongst this plethora of genetic changes, NOTCH1 activating mutations stand out as the most frequently occurring genetic defect, identified in more than 50% of T-cell acute lymphoblastic leukemias, supporting an essential driver role for this gene in T-cell acute lymphoblastic leukemia oncogenesis. In this study, we aimed to establish a comprehensive compendium of the long non-coding RNA transcriptome under control of Notch signaling. For this purpose, we measured the transcriptional response of all protein coding genes and long non-coding RNAs upon pharmacological Notch inhibition in the human T-cell acute lymphoblastic leukemia cell line CUTLL1 using RNA-sequencing. Similar Notch dependent profiles were established for normal human CD34+ thymic T-cell progenitors exposed to Notch signaling activity in vivo. In addition, we generated long non-coding RNA expression profiles (array data) from GSI treated T-ALL cell lines, ex vivo isolated Notch active CD34+ and Notch inactive CD4+CD8+ thymocytes and from a primary cohort of 15 T-cell acute lymphoblastic leukemia patients with known NOTCH1 mutation status. Integration of these expression datasets with publically available Notch1 ChIP-sequencing data resulted in the identification of long non-coding RNAs directly regulated by Notch activity in normal and malignant T-cell context. Given the central role of Notch in T-cell acute lymphoblastic leukemia oncogenesis, these data pave the way towards development of novel therapeutic strategies that target hyperactive Notch1 signaling in human T-cell acute lymphoblastic leukemia. Overall design: CUTLL1 cell lines were treated with Compound E (GSI) or DMSO (solvent control). Cells were collected 12 h and 48 h after treatment. This was performed for 3 replicates. RNA-sequencing was performed on these samples.
The Notch driven long non-coding RNA repertoire in T-cell acute lymphoblastic leukemia.
No sample metadata fields
View SamplesTranscription factor complexes bind to regulatory sequences of genes, providing a system of individual expression regulation. Targets of distinct transcription factors usually map throughout the genome, without clustering. Nevertheless, highly and weakly expressed genes do cluster in separate chromosomal domains with an average size of 80 to 90 genes. We therefore asked whether, besides transcription factors, an additional level of gene expression regulation exists that acts on chromosomal domains. Here we show that identical green fluorescent protein (GFP) reporter constructs integrated at 90 different chromosomal positions determined by sequencing, obtain expression levels that correspond to the activity of the domains of integration. These domains are about 80 genes long and can exert an effect of up to 8-fold on the expression of integrated genes. 3D-FISH shows that active domains of integration have a more open chromatin structure than integration domains with weak activity. These results reveal a novel domain-wide regulatory mechanism that, together with transcription factors, exerts a dual control over gene transcription.
Domain-wide regulation of gene expression in the human genome.
No sample metadata fields
View SamplesNeuroblastoma is an embryonal tumour of the peripheral sympathetic nervous system (SNS). One of the master regulator genes for peripheral SNS differentiation, the homeobox transcription factor PHOX2B, is mutated in familiar and sporadic neuroblastomas. Here we report that inducible expression of PHOX2B in the neuroblastoma cell line SJNB-8 down-regulates MSX1, a homeobox gene important for embryonic neural crest development. Inducible expression of MSX1 in SJNB-8 caused inhibition of both cell proliferation and colony formation in soft agar. Affymetrix micro- array and Northern blot analysis demonstrated that MSX1 strongly up-regulated the Delta-Notch pathway. These experiments describe for the first time regulation of the Delta-Notch pathway by MSX1, and connect these genes to the PHOX2B oncogene, indicative of a role in neuroblastoma biology.
The MSX1 homeobox transcription factor is a downstream target of PHOX2B and activates the Delta-Notch pathway in neuroblastoma.
No sample metadata fields
View SamplesEnterotoxigenic Escherichia coli (ETEC) strains that produce both heat-stable (ST) and heat-labile (LT) enterotoxins cause severe post-weaning diarrhea in piglets. However, the relative importance of the individual enterotoxins to the pathogenesis of ETEC infection is poorly understood. In this study, we investigated the effect on virulence of an F4+ ETEC strain when removing some or all of its enterotoxins. Several isogenic mutant strains were constructed that lack the expression of LT in combination with one or both types of ST enterotoxins (STa and/or STb). Host early immune responses induced by these mutant strains 4h after infection were compared to the wild type strain GIS26 (O149:F4ac+, LT+ STa+ STb+). At the same time, the immune response of this wild type ETEC strain was compared to the mock-infected control, demonstrating the expression of porcine inflammatory response genes. For these purposes, the small intestinal segment perfusion (SISP) technique and microarray analysis were used and results were validated by qRT-PCR. We also measured net fluid absorption of pig small intestinal mucosa 4h after infection with wild type ETEC, the mutant strains and PBS (mock-infected). These data indicate an important role for STb in inducing small intestinal secretion early after infection. The microarray analysis of the different mutant strains also revealed an important role for STb in ETEC-induced immune response by the significant differential regulation of immune mediators like matrix metalloproteinase 3, interleukin 1 and interleukin 17. We conclude that STb can play a prominent role in ETEC-induced secretion and early immune response.
Role of heat-stable enterotoxins in the induction of early immune responses in piglets after infection with enterotoxigenic Escherichia coli.
Sex, Specimen part, Treatment
View SamplesBackground: Although several studies link high levels of IL-6 and soluble IL-6 receptor (sIL-6R) with asthma severity and decreased lung function, the role of IL-6 trans-signaling (IL-6TS) in asthma is unclear. Objective: To explore the association between epithelial IL-6TS pathway activation and molecular and clinical phenotypes in asthma. Methods: Primary human bronchial epithelial cell (HBEC) air-liquid interface (ALI) cultures were stimulated with IL-6 and sIL-6R to establish an IL-6TS gene signature. Two separate RNA sequencing (RNA-seq) studies were performed: The “IL-6 vs T2 study” compared gene expression after stimulation with control medium, IL-6, IL-6/sIL-6R and IL-4/IL-13, while the “JAK1-inhibition study” addressed the effect of JAK1 inhibition on IL-6TS induced gene expression. The IL-6TS gene signature was used to stratify lung epithelial transcriptomic data obtained from asthmatics (n=103) in the U-BIOPRED cohorts by hierarchical clustering. Molecular phenotyping was based on the transcriptional profiling of epithelial brushings, pathway analysis and immunohistochemistry analysis of bronchial biopsies. Results: Activation of IL-6TS in HBEC ALI cultures reduced epithelial barrier function and induced a specific epithelial gene signature enriched in airway remodeling genes. The IL-6TS signature identified a subset (n=17) of IL-6TS High asthma patients with increased epithelial expression of IL-6TS inducible genes in absence of increased systemic levels of IL-6 and sIL-6R. The IL-6TS High subset had an increased exacerbation frequency (p=0.028), blood (>300/µl; p=0.0028) and sputum (>20%; p=0.007) eosinophilia, and submucosal infiltration of CD4 T cells, CD8 T cells (p<0.001) and macrophages (p=0.001). In bronchial brushings, TLR pathway genes were up-regulated while the expression of epithelial tight junction genes was reduced (all with q<0.05). Sputum sIL-6R levels correlated with sputum markers of remodeling and innate immune activation, in particular YKL-40, MMP3, IL-8 and IL-1ß (all with q<0.001). Conclusions: Local lung epithelial IL-6TS activation in absence of type 2 airway inflammation defines a novel subset of asthmatics and may drive airway inflammation and epithelial dysfunction in these patients. Overall design: Primary human bronchial epithelial cells grown and differentiated on air-liquid interface were stimulated basolaterally for 24h with cytokines corresponding to IL-6TS (IL-6 + sIL-6R), IL-6 alone, a Type 2 immune response (IL-4 + IL-13) or media alone as non-stimulated control. Each stimulation condition was done in triplicates. Cells were lysed, the RNA isolated and converted into libraries then used for next generation sequencing in order to identify genes that were up- or downregulated in response to the different stimulations.
Epithelial IL-6 trans-signaling defines a new asthma phenotype with increased airway inflammation.
Specimen part, Subject
View SamplesmRNA profiles of thousands of human tumors are available, but methods to deduce oncogenic signaling networks from these data lag behind. It is especially challenging to identify main-regulatory routes, and to generalize conclusions obtained from experimental models. We designed the bioinformatic platform R2 (http://r2.amc.nl) in parallel with a wet-lab approach of neuroblastoma. Here we demonstrate how R2 facilitates an integrated analysis of our neuroblastoma data. Analysis of the MYCN pathway suggested important regulatory connections to the polyamine synthesis route, the Notch pathway and the BMP/TGF pathway. A network of genes emerged connecting major oncogenes in neuroblastoma. Genes in the network carried strong prognostic values and were essential for tumor cell survival.
Deoxyhypusine synthase (DHPS) inhibitor GC7 induces p21/Rb-mediated inhibition of tumor cell growth and DHPS expression correlates with poor prognosis in neuroblastoma patients.
Specimen part, Cell line
View SamplesmRNA profiles of thousands of human tumors are available, but methods to deduce oncogenic signaling networks from these data lag behind. It is especially challenging to identify main-regulatory routes, and to generalize conclusions obtained from experimental models. We designed the bioinformatic platform R2 (http://r2.amc.nl) in parallel with a wet-lab approach of neuroblastoma. Here we demonstrate how R2 facilitates an integrated analysis of our neuroblastoma data. Analysis of the MYCN pathway suggested important regulatory connections to the polyamine synthesis route, the Notch pathway and the BMP/TGF pathway. A network of genes emerged connecting major oncogenes in neuroblastoma. Genes in the network carried strong prognostic values and were essential for tumor cell survival.
Deoxyhypusine synthase (DHPS) inhibitor GC7 induces p21/Rb-mediated inhibition of tumor cell growth and DHPS expression correlates with poor prognosis in neuroblastoma patients.
Specimen part, Cell line
View SamplesSVGR2 cells are glial cells which are derived from SVG-A cells. They were created by subjecting SVG-A cells to multiple rounds of lytic infection by the human polyomavirus JCV. SVGR2 cells are the cells that survived this process and are resistant to JCV infection. This experiment was designed to identify gene expression differences that may be responsible for SVGR2 resistance to JCV.
Microarray analysis of glial cells resistant to JCV infection suggests a correlation between viral infection and inflammatory cytokine gene expression.
No sample metadata fields
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