To define molecular mechanisms underlying rod and cone differentiation, we generated H9 human embryonic stem cell line carrying a GFP reporter that is controlled by the promoter of cone-rod homeobox (CRX) gene, the first known marker of post-mitotic photoreceptor precursors. CRXp-GFP reporter in H9 line replicates endogenous CRX expression when induced to form self-organizing 3-D retina-like tissue. We define temporal transcriptome dynamics of developing photoreceptors during the establishment of cone and rod cell fate. Our studies provide an essential framework for delineating molecules and cellular pathways that guide human photoreceptor development and should assist in chemical screening and cell-based therapies of retinal degeneration. Overall design: Undifferentiated CRXp-GFP HP hES cells and 3D-neural retina were collected at days 37, 47, 67 and 90 and dissociated into single cells. Cells were sorted at 4°C and by FACSAria (Becton Dickinson). GFP+ and GFP- cells were separately collected. Total RNA was extracted by RNA purification kit (Norgen Biotek) and analyzed by 2100 Bioanalyzer (Agilent Technologies Genomics). High quality of total RNA (RIN: 7.7-9.2) was subjected to libraries construction using 40-60 ng of total RNA as input. Libraries were constructed using a stranded modification of the Illumina TruSeq mRNA (Brooks, et al. Meth Mol Biol 2012). Each library was single-end sequenced in an independent lane of a GAIIx at a length of 76 bases. Fastq files were generated from reads passing chastity filter.
Transcriptome Dynamics of Developing Photoreceptors in Three-Dimensional Retina Cultures Recapitulates Temporal Sequence of Human Cone and Rod Differentiation Revealing Cell Surface Markers and Gene Networks.
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View SamplesWe discuss the use of pluripotent stem cell lines carrying fluorescent reporters driven by retinal promoters to derive three-dimensional (3-D) retina in culture and how this system can be exploited for elucidating human retinal biology, creating disease models in a dish, and designing targeted drug screens for retinal and macular degeneration. Furthermore, we realize that stem cell investigations are labor-intensive and require extensive resources. To expedite scientific discovery by sharing of resources and to avoid duplication of efforts, we propose the formation of a Retinal Stem Cell Consortium. In the field of vision, such collaborative approaches have been enormously successful in elucidating genetic susceptibility associated with age-related macular degeneration. Overall design: CRX+ flow sorted cells from human retina derived organoids were collected at 6 time points during differentiation (day (D) 37, 48, 67, 90, 134, 220).
Treatment Paradigms for Retinal and Macular Diseases Using 3-D Retina Cultures Derived From Human Reporter Pluripotent Stem Cell Lines.
Specimen part, Subject
View SamplesWe report that Dnmt1 is crucial during perinatal intestinal development. Loss of Dnmt1 in intervillus progenitor cells causes global hypomethylation, DNA damage, premature differentiation, and apoptosis, and consequently, loss of nascent villi. We further confirm the critical role for Dnmt1 during crypt development using the in vitro organoid culture system, and illustrate a clear differential requirement for Dnmt1 in immature versus mature organoids. These results demonstrate an essential role for Dnmt1 in maintaining genomic stability during intestinal development and the establishment of intestinal crypts. Overall design: We performed RNA-Seq of control and Dnmt1-ablated intestinal progenitor cells isolated from parrafin embedded tissues by laser capture microdissection (LCM).
Dnmt1 is essential to maintain progenitors in the perinatal intestinal epithelium.
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View SamplesBackground and Aims: HNF4a is a nuclear hormone receptor transcription factor that has been shown to be required for hepatocyte differentiation and development of the liver. It has also been implicated in regulating expression of genes that act in the epithelium of the lower gastrointestinal tract. This implied that HNF4a might be required for development of the gut. Methods: We generated mouse embryos in which HNF4a was ablated in the epithelial cells of the fetal colon using Cre-loxP technology. Embryos were examined using a combination of histology, immunohistochemistry, gene array and RT-PCR, and chromatin immunoprecipitation analyses to define the consequence of loss of HNF4a on colon development. Results: Embryos could be generated until E18.5 that lacked HNF4a in their colon. Although, early stages of colonic development occurred, HNF4a null colons failed to form normal crypts. In addition, goblet cell maturation was perturbed and expression of an array of genes that encode proteins with diverse roles in colon function was disrupted. Several genes whose expression in the colon was dependent on HNF4a contained HNF4abinding sites sequences within putative transcriptional regulatory regions and a subset of these sites were occupied by HNF4a in vivo. Conclusion: HNF4a is a transcription factor that is essential for development of the mammalian colon, regulates goblet cell maturation and is required for expression of genes that control normal colon function and epithelial cell differentiation.
Hepatocyte nuclear factor 4alpha is essential for embryonic development of the mouse colon.
Specimen part
View SamplesThe composition of chromatin remodeling complexes dictates how these enzymes control transcriptional programs and cellular identity. Here, we investigate the composition of SWI/SNF complexes in embryonic stem cells (ESCs). In contrast to differentiated cells, ESCs have a biased incorporation of certain paralogous SWI/SNF subunits, with low levels of Brm, BAF170 and ARID1B. Upon differentiation, the expression of these subunits increases, resulting in a higher diversity of compositionally distinct SWI/SNF enzymes. We also identify Brd7 as a novel component of the PBAF complex in both ESCs and differentiated cells. Using shRNA-mediated depletion of Brg1, we show that SWI/SNF can function as both a repressor and an activator in pluripotent cells, regulating expression of developmental modifiers and signaling components such as Nodal, ADAMTS1, Bmi-1, CRABP1 and TRH. Knock-down studies of PBAF-specific Brd7 and of a signature subunit within the BAF complex, ARID1A, show that these two sub-complexes affect SWI/SNF target genes differentially, in some cases even antagonistically. This may be due to their different biochemical properties. Finally, we examine the role of SWI/SNF in regulating its target genes during differentiation. We find that SWI/SNF affects recruitment of components of the pre-initiation complex in a promoter-specific manner, to modulate transcription positively or negatively. Taken together, our results provide insight into the function of compositionally diverse SWI/SNF enzymes that underlie their inherent gene-specific mode of action.
BRD7, a novel PBAF-specific SWI/SNF subunit, is required for target gene activation and repression in embryonic stem cells.
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View SamplesMicroRNAs fine-tune the activity of hundreds of protein-coding genes. The identification of tissue-specific microRNAs and their promoters has been constrained by the limited sensitivity of prior microRNA quantification methods. Here we determine the entire microRNAome of three endoderm-derived tissues, liver, small intestine, and pancreas, using ultra-high throughput sequencing. Although many microRNA genes are expressed at comparable levels, 162 microRNAs exhibited striking tissue-specificity. After mapping the promoters for these microRNA genes using H3K4me3 histone occupancy, we analyzed the regulatory modules of 63 microRNAs differentially expressed between liver and small intestine or pancreas. We determined that the same transcriptional regulatory mechanisms govern tissue-specific gene expression of both mRNA and microRNA encoding genes in mammals.
Tissue-specific regulation of mouse microRNA genes in endoderm-derived tissues.
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View SamplesIn this study we examined the effect of T cell-derived cytokines on retinal pigment epithelial (RPE) cells with respect to expression of complement components. We used an in vitro co-culture system in which CD3/CD28-activated human T cells were separated from the human RPE cell line (ARPE-19) by a membrane. Differential gene expression in the RPE cells of complement factor genes was identified using gene arrays, and selected gene transcripts were validated by q-RT-PCR. Protein expression was determined by ELISA and immunoblotting. Co-culture with activated T cells increased RPE mRNA and/or protein expression of complement components C3, factors B, H, H-like 1, CD46, CD55, CD59, and clusterin, in a dose-dependent manner. Soluble factors derived from activated T cells are capable of increasing expression of complement components in RPE cells. This is important for the further understanding of inflammatory ocular diseases such as uveitis and age-related macular degeneration.
Retinal pigment epithelial cells upregulate expression of complement factors after co-culture with activated T cells.
Disease, Disease stage
View SamplesWe successfully sequenced and annotated more than 400 cells from child, adult control, type 1 diabetes and type 2 diabetes donors. We detect donor-type specific transcript variation. We also report that cells from child donors have less defined gene signature. Cells from type 2 diabetes donors resemble juvenile cells in gene expression. Overall design: Cells from three adult controls (56, 74, 92), one donor with type 1 diabetes (91), two donors with type 2 diabetes (75, 143), and two child donors (40, 72) were sequenced. Numbers in parathesis indicates number of cells sequenced.
Single-Cell Transcriptomics of the Human Endocrine Pancreas.
Specimen part, Subject
View SamplesCopy number variation (CNV) of DNA segments has recently been identified as a major source of genetic diversity, but a more comprehensive understanding of the extent and phenotypic effect of this type of variation is only beginning to emerge. In this study we generated genome-wide expression data from 6 mouse tissues to investigate how CNVs influence gene expression.
Segmental copy number variation shapes tissue transcriptomes.
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View SamplesExpression data from Caenorhabditis elegans let-418(RNAi), mep-1(RNAi) and gfp(RNAi) L1 larvae.
Different Mi-2 complexes for various developmental functions in Caenorhabditis elegans.
Disease
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