Genome instability is a potential limitation to the research and therapeutic application of induced pluripotent stem cells (iPSCs). Observed genomic variations reflect the combined activities of DNA damage, cellular DNA damage response (DDR), and selection pressure in culture. To understand the contribution of DDR on the distribution of copy number variations (CNVs) in iPSCs, we mapped CNVs of iPSCs with mutations in the central DDR gene ATM onto genome organization landscapes defined by genome-wide replication timing profiles. We show that following reprogramming the early and late replicating genome is differentially affected by CNVs in ATM deficient iPSCs relative to wild type iPSCs. Specifically, the early replicating regions had increased CNV losses during retroviral reprogramming. This differential CNV distribution was not present after later passage or after episomal reprogramming. Comparison of different reprogramming methods in the setting of defective DNA damage response reveals unique vulnerability of early replicating open chromatin to retroviral vectors.
Influence of ATM-Mediated DNA Damage Response on Genomic Variation in Human Induced Pluripotent Stem Cells.
Specimen part
View SamplesWe report the correlation between lung-derived neonatal MSCs and 2 clinical variables among preterm newborns: corrected gestational age (CGA) at collection and the severity of bronchopulmonary dysplasia (BPD) Overall design: To test the correlation between the transcriptional profiles of tracheal aspirate-derived mesenchymal stromal cells with late stage lung development and with bronchopulmonary dysplasia.
Lung-Resident Mesenchymal Stromal Cells Reveal Transcriptional Dynamics of Lung Development in Preterm Infants.
Specimen part, Subject
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The distribution of genomic variations in human iPSCs is related to replication-timing reorganization during reprogramming.
Sex, Age, Specimen part, Disease, Disease stage, Subject, Time
View SamplesCell fate change involves significant genome reorganization, including change in replication timing, but how these changes are related to genetic variation has not been examined. To study how change in replication timing that occurs during reprogramming impacts the copy number variation (CNV) landscape, we generated genome-wide replication timing profiles of induced pluripotent stem cells (iPSCs) and their parental fibroblasts. A significant portion of the genome changes replication timing as a result of reprogramming, indicative of overall genome reorganization. We found that early and late replicating domains in iPSCs are differentially affected by copy number gains and losses, and that in particular CNV gains accumulate in regions of the genome that change to earlier replication during the reprogramming process. This differential relationship was present irrespective of reprogramming method. Overall, our findings reveal a functional association between reorganization of replication timing and the CNV landscape that emerges during reprogramming.
The distribution of genomic variations in human iPSCs is related to replication-timing reorganization during reprogramming.
Specimen part, Disease, Disease stage, Subject
View SamplesDifferentiation of human pluripotent stem cells toward definitive endoderm (DE) is the critical first step for generating cells comprising organs such as the gut, liver, pancreas and lung. This in-vitro differentiation process generates a heterogeneous population with a proportion of cells failing to differentiate properly and maintaining expression of pluripotency factors such as Oct4. RNA-sequencing of single cells collected at four time points during a 4-day DE differentiation identified high expression of metallothionein genes in the residual Oct4-positive cells that failed to differentiate to DE. Using X-ray fluorescence microscopy and multi-isotope mass spectrometry, we discovered that high intracellular zinc level corresponds with persistent Oct4 expression and failure to differentiate. We further show that differentiation-arrested phenotype is inversely correlated with zinc concentration in the differentiation media. This study improves our understanding of in-vitro DE differentiation and provides actionable options to improve DE differentiation efficiency. Overall design: RNA-sequencing of 329 single cells collected at four time points during a 4-day DE differentiation to identify mechanisms leading to cellular heterogeneity during differentiation
Single-cell RNA sequencing reveals metallothionein heterogeneity during hESC differentiation to definitive endoderm.
Specimen part, Subject, Time
View SamplesPluripotency, the capacity of embryo-derived stem cells to generate all tissues in the organism, can be induced in somatic cells by nuclear transfer into oocyte, fusion with embryonic stem cells, and for male germ cells by cell culture alone. Recently, murine fibroblasts have been reprogrammed directly to pluripotency by ectopic expression of four transcription factors (Oct4, Sox2, Klf4, and Myc) to yield induced Pluripotent Stem (iPS) cells. Using the same four factors, we have derived iPS cells from human embryonic stem cell-derived fibroblasts, primary human fetal cells, and diverse cells of neonatal and adult human origin. The human iPS cells manifest the colony morphology, gene expression patterns, and epigenetic characteristics of human Embryonic Stem (hES) cells, and form well-differentiated teratomas in immune-deficient mice. These data demonstrate that defined factors can reprogram human cells to pluripotency, and establish a method whereby patient-specific cells might be established in culture.
Reprogramming of human somatic cells to pluripotency with defined factors.
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View SamplesTRIM24 and TRIM33 interact to form a corepressor complex that suppresses murine hepatocellular carcinoma (HCC). TRIM24 and TRIM33 cooperatively repress retinoic acid receptor dependent activity of VL30 retro-transposons in hepatocytes in vivo. In TRIM24 knockout hepatocytes, VL30 long terminal repeats (LTRs) generate enhancer (e)RNAs and act as surrogate promoter and enhancer elements deregulating expression of neighbouring genes. We show that a VL30 LTR-derived eRNA is essential to activate the lipocalin 13 gene in hepatocytes in vivo. A further consequence of VL30 de-repression is the accumulation of retro-transcribed VL30 DNA in the cytoplasm of TRIM24-mutant hepatocytes and activation of the viral defence/interferon response. VL30 activation therefore modulates gene expression via the enhancer activity of the LTRs and by activation of the interferon response. Both of these processes are genetically linked to HCC development suggesting that VL30 repression by TRIM24 plays an important role in tumour suppression. Overall design: RNA profiles in liver of wild type (WT) and Trim24-/- mice by deep sequencing using Illumina GAIIx.
Trim24-repressed VL30 retrotransposons regulate gene expression by producing noncoding RNA.
Age, Specimen part, Cell line, Subject
View SamplesPurpose: The population of muscle-derived stem cells called MuStem cells is presented as promising candidate for cell-based therapy of muscle diseases. To validate if this agent can be really presented as therapeutic product and so to be eligible to a future clinical use, it is now required to demonstrate beforehand an efficacy with cells prepared in compliance with good manufacturing practices (GMPs). The aim of the current study was to evaluate the use of two xeno-free blood derivatives corresponding to human serum (HS) and human platelet lysate (hPL) as alternatives to controverted but until now used fetal bovine serum (FBS) for isolation and expansion of human MuStem (hMuStem) cells. Methods: A comparative study was performed with hMuStem cells isolated and in vitro expanded by using commercially available HS and hPL to determine its impact on their proliferation rates, clonogenicity, myogenic commitment level and oligopotency with regard to results obtained under FBS-based medium. Also, their respective phenotype and global gene expression patterns were investigated by flow cytometry and high throughput 3' digital gene expression RNA-sequencing in order to define a possible differential impact of the human nutrients tested. Results: Comparatively to FBS-based medium, use of HS- and hPL-supplemented ones efficiently supported long-term proliferation of hMuStem cells and enhanced clonogenicity, without main modification of their expression profile and allowing besides limiting the supplementation in growth factors. In vitro differentiation assay combined to transforming growth factor ß1 (TGF-ß1)-depletion experiments showed a lower myogenic commitment level as well as fusion ability of hMuStem cells when cultured with hPL-based medium according to a TGF-ß1-independent process. Use of hPL-derived 3D hydrogel or fibrinogen-depleted hPL demonstrated that heparin-free hPL derivatives maintain consequent myogenic differentiation potential. In addition, the reduced myogenicity was shown to be rapidly reversible following replacement of hPL by HS or fibrinogen-depleted hPL. Conclusions: All together, our original findings position HS and hPL as efficient and suitable alternatives to FBS for preparation of hMuStem cell batch in compliance with GMPs. Overall design: mRNA profile of hMuStem cells cultured in hPL was compared to the mRNA profile of hMuStem cells cultured in HS. The profiles were generated in triplicates using the 3''DGE-Seq technology.
Human serum and platelet lysate are appropriate xeno-free alternatives for clinical-grade production of human MuStem cell batches.
Specimen part, Subject
View SamplesCilia are ubiquitous cell surface projections that modulate various sensory- and motility based processes and are implicated in a growing number of multi-organ genetic disorders termed ciliopathies. As new components required for cilium biogenesis and function remain unidentified, we sought to further define and validate the transcriptional targets of the ciliogenic C. elegans RFX transcription factor DAF-19. To this end, transcriptional profiling of daf-19 mutants (which do not form cilia) and wild-type animals was performed using selectively staged embryos where ciliogenesis occurs in most ciliated sensory neurons
Transcriptional profiling of C. elegans DAF-19 uncovers a ciliary base-associated protein and a CDK/CCRK/LF2p-related kinase required for intraflagellar transport.
Specimen part
View SamplesTyrosine phosphorylation is a hallmark for activation of Signal Transducer and Activator of Transcription (STAT) proteins, but their transcriptional activity also depends on other secondary modifications. Type I interferons (IFNs) can activate both the ISGF3 (STAT1:STAT2:IRF9) complex and STAT3, but with cell-specific, selective triggering of only the ISGF3 transcriptional program. Following a genome-wide RNAi screen, we identified the Sin3a complex as an important mediator of this STAT3 transcriptional repression. Sin3a directly interacts with the DNA-binding domain of STAT3 and alters its acetylation status. SIN3A silencing enhances recruitment of STAT3 and enhanceosome components to the SOCS3 promoter, resulting in histone hyperacetylation and enhanced transcription. Conversely, Sin3a is required for ISGF3-dependent gene transcription and for an efficient IFN-mediated antiviral protection against Influenza A and hepatitis C viruses. The Sin3a complex therefore acts as a context-dependent STAT1/3 transcriptional switch.
The Sin3a repressor complex is a master regulator of STAT transcriptional activity.
Cell line, Treatment
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