Ischemic cardiopathy is the leading cause of death in the world, for which efficient regenerative therapy is not currently available. In mammals, after a myocardial infarction episode, the damaged myocardium is replaced by scar tissue featuring collagen deposition and tissue remodelling with negligible cardiomyocyte proliferation. Zebrafish, in contrast, display an extensive regenerative capacity as they are able to restore completely lost cardiac tissue after partial ventricular amputation. Due to the lack of genetic lineage tracing evidence, it is not yet clear if new cardiomyocytes arise from existing contractile cells or from an uncharacterised set of progenitors cells. Nonetheless, several genes and molecules have been shown to participate in this process, some of them being cardiomyocyte mitogens in vitro. Though questions as what are the early signals that drive the regenerative response and what is the relative role of each cardiac cell in this process still need to be answered, the zebrafish is emerging as a very valuable tool to understand heart regeneration and devise strategies that may be of potential value to treat human cardiac disease. Here, we performed a genome-wide transcriptome profile analysis focusing on the early time points of zebrafish heart regeneration and compared our results with those of previously published data. Our analyses confirmed the differential expression of several transcripts, and identified additional genes the expression of which is differentially regulated during zebrafish heart regeneration. We validated the microarray data by conventional and/or quantitative RT-PCR. For a subset of these genes, their expression pattern was analyzed by in situ hybridization and shown to be upregulated in the regenerating area of the heart. The specific role of these new transcripts during zebrafish heart regeneration was further investigated ex vivo using primary cultures of zebrafish cardiomyocytes and/or epicardial cells. Our results offer new insights into the biology of heart regeneration in the zebrafish and, together with future experiments in mammals, may be of potential interest for clinical applications.
Transcriptomics approach to investigate zebrafish heart regeneration.
Specimen part, Time
View SamplesLung alveolarization is a complex process that involves interactions between several cell types and leads to considerable increase in gas-exchange surface area. The step designated secondary septation includes elastogenesis from interstitial fibroblasts.
Gene expression profiling in lung fibroblasts reveals new players in alveolarization.
No sample metadata fields
View SamplesThe events regulating human preimplantation development are still largely unknown, due to scarcity of material, ethical and legal limitations, and lack of reliable techniques to faithfully amplify the transcriptome of a single cell. Nonetheless, knowledge in human embryology is gathering renewed interest due to its close relationship with both stem cell biology and epigenetic reprogramming to pluripotency, and their centrality to regenerative medicine. Using carefully timed genome-wide transcript analyses on single oocytes and embryos, the analysis of the data allowed us to uncover a series of successive waves of embryonic transcriptional initiation which start as early as the 2 cell stage. In addition, we identified hierarchical activation of genes involved in the regulation of pluripotency. Finally, we developed HumER, a free database of human preimplantation human development gene expression to serve the scientific community. Importantly, our work links early transcription in the human embryo with the correct execution of the pluripotency program later in development, and paves the way for the identification of factors to improve epigenetic reprogramming.
Waves of early transcriptional activation and pluripotency program initiation during human preimplantation development.
Specimen part, Cell line
View SamplesMolecular mechanisms that are responsible for the development of human skin epithelial cells are not completely understood so far. As a consequence, the efficiency to establish a pure skin epithelial cell population from human induced pluripotent stem cells (hiPSC) remains poor. Using an approach including RNA interference and high-throughput imaging of early epithelial cells, we could identify candidate kinases which are involved in skin epithelial differentiation. Among them, we found HIPK4 to be an important inhibitor of this process. Indeed, its silencing increased the amount of generated skin epithelial precursors, increased the amount of generated keratinocytes and improved growth and differentiation of organotypic cultures, allowing for the formation of a denser basal layer and stratification with the expression of several keratins. Our data bring substantial input in the regulation of human skin epithelial differentiation and for improving differentiation protocols from pluripotent stem cells.
An RNAi Screen Reveals an Essential Role for HIPK4 in Human Skin Epithelial Differentiation from iPSCs.
Specimen part, Time
View SamplesThree different progenitor cell subsets in subcutaneous and visceral adipose tissues derived from 5 obese patients were subjected to AmpliSeq transcriptome profiling. Transcriptomic profiles were analyzed to compare progenitor cell subsets and the impact of subcutaneous and visceral adipose tissue location. Overall design: Transcriptomic profiling of 3 different progenitor cell types in subcutaneous and visceral adipose tissues derived from 5 obese patients (3X2X5=30 samples).
Lobular architecture of human adipose tissue defines the niche and fate of progenitor cells.
Subject
View SamplesThe generation of induced pluripotent stem (iPS) cells 1-4 has spawned unprecedented opportunities for investigating the molecular logic that underlies cellular pluripotency and reprogramming, as well as for obtaining patient-specific cells for future clinical applications. However, both prospects are hampered by the low efficiency of the reprogramming process. Here, we show that juvenile human primary keratinocytes can be efficiently reprogrammed to pluripotency by retroviral transduction with Oct4, Sox2, Klf4 and c-Myc. Keratinocyte-derived iPS (KiPS) cells appear indistinguishable from human embryonic stem (hES) cells in colony morphology, growth properties, expression of pluripotency-associated transcription factors and surface markers, as well as in vitro and in vivo differentiation potential. Notably, keratinocyte reprogramming to pluripotency is, at least, 100-fold more efficient and 2-fold faster than that of fibroblasts. This increase in reprogramming efficiency allowed us to expand the practicability of the technology and to generate KiPS cells from single plucked hairs from adult individuals.
Efficient and rapid generation of induced pluripotent stem cells from human keratinocytes.
No sample metadata fields
View SamplesInduced pluripotent stem (iPS) cells have generated interest for regenerative medicine as they allow for producing patient-specific progenitors in vitro with potential value for cell therapy. In many instances, however, an off-the-shelf approach would be desirable, such as for cell therapy of acute conditions or when the patient's somatic cells are altered as a consequence of chronic disease or aging. Cord blood (CB) stem cells appear ideally suited for this purpose as they are newborn, immunologically immature cells with minimal genetic and epigenetic alterations, and several hundred thousand immunotyped CB units are readily available through a worldwide network of CB banks. Here, we show that CB stem cells can be reprogrammed to pluripotency by retroviral transduction with OCT4, SOX2, KLF4, and c-MYC, in a process that is extremely efficient and fast. The resulting CB-derived iPS (CBiPS) cells are phenotypically and molecularly indistinguishable from human embryonic stem (hES) cells. Furthermore, we show that generation of CBiPS can be efficiently achieved without the use of the c-MYC and KLF4 oncogenes and just by overexpression of OCT4 and SOX2. Our studies set the basis for the creation of a comprehensive bank of HLA-matched CBiPS cells for off-the-shelf applications.
Generation of induced pluripotent stem cells from human cord blood using OCT4 and SOX2.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Chronic mucocutaneous candidiasis and connective tissue disorder in humans with impaired JNK1-dependent responses to IL-17A/F and TGF-β.
Specimen part, Disease, Disease stage, Treatment, Time
View SamplesThe size and scope of microarray experiments continue to increase. However, datasets generated on different platforms or at different centres contain biases. Improved techniques are needed to remove platform- and batch-specific biases. One experimental control is the replicate hybridization of a subset of samples at each site or on each platform to learn the relationship between the two platforms. To date, no algorithm exists to specifically use this type of control. LTR is a linear-modelling-based algorithm that learns the relationship between different microarray batches from replicate hybridizations. LTR was tested on a new benchmark dataset of 20 samples hybridized to different Affymetrix microarray platforms. Before LTR, the two platforms were significantly different; application of LTR removed this bias. LTR was tested with six separate data pre-processing algorithms, and its effectiveness was independent of the pre-processing algorithm. Sample-size experiments indicate that just three replicate hybridizations can significantly reduce bias. An R library implementing LTR is available.
LTR: Linear Cross-Platform Integration of Microarray Data.
Sex
View SamplesTo identify the CD4+ T cell cytokines responsible for the proliferation of the Lin-IEL lines CD4+ T cell clone L10, which recognises DQ2-glia-1, one of the immunodominant T cell epitopes in celiac disease, was stimulated for 3 hours in IMDM with plate-bound CD3/CD28-specific (2.5 g/ml each) or control antibodies coated onto 6-well non-tissue culture treated plates. Three independent biological replicates were performed, each time including 6 million Ficoll-purified live cells per condition. RNA was purified from these cells using the RNAeasy mini kit (Qiagen, Venlo, the Netherlands). cDNA was amplified using the Applause WT-Amp system (NuGEN technologies, Bemmel, the Netherlands) and biotin-labelled with the Encore Biotin Module (NuGEN). Human Gene 1.0 ST arrays (Affymetrix, High Wycombe, UK) were employed to quantify global gene expression.
CD4 T-cell cytokines synergize to induce proliferation of malignant and nonmalignant innate intraepithelial lymphocytes.
Specimen part
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