We previously showed that severe liver diseases are characterized by expansion of liver progenitor cells (LPC), which correlates with disease severity. However, the origin and role of LPC in liver physiology and in the hepatic response to injury remains a contentious topic. We have now used genetic lineage tracing of Hnf1-expressing biliary duct cells to assess their contribution to LPC expansion and hepatocyte generation during normal liver homeostasis, and following different types of liver injury. We found that ductular reaction cells in human cirrhotic livers express HNF1. However, HNF1 expression was not present in newly generated EpCAM-positive hepatocytes. Using a tamoxifen-inducible Hnf1CreER/R26RYFP/LacZ mouse, we show that there is no contribution of the biliary epithelium to hepatocyte turnover during liver homeostasis in healthy mice. Moreover, after loss of liver mass, Hnf1+ LPC did not contribute to hepatocyte regeneration. We also assessed the contribution of Hnf1+ cells following acute and repeated liver injury. All animal models showed expansion of LPC, as assessed by immunostaining and gene expression profile of sorted YFP-positive cells. A contribution of Hnf1+ LPC to hepatocyte generation was not detected in animal models of liver injury with preserved hepatocyte regenerative potential such as acute acetaminophen, carbon tetrachloride injury, or chronic diethoxycarbonyl-1,4-dihydro-collidin (DDC)-diet. However, in mice fed with choline-deficient ethionine-supplemented (CDE)-diet, which causes profound hepatocyte damage and arrest, a small number of hepatocytes were derived from Hnf1+ cells. Conclusion: Hnf1+ cells do not participate in hepatocyte turnover in the healthy liver or during liver regeneration after partial hepatectomy. After liver injury, LPC arise from the biliary duct epithelium, which gives rise to a limited number of hepatocytes only when hepatocyte regeneration is compromised.
The biliary epithelium gives rise to liver progenitor cells.
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View SamplesPurpose: Avian photoreceptors are a diverse class of neurons, comprised of four single cones, the two members of the double cone, and rods. Many distinctive features of photoreceptor subtypes, including spectral tuning, oil droplet size and pigmentation, synaptic targets and spatial patterning, have been well characterized, but the molecular mechanisms underlying these attributes have not been explored. Furthermore, the signaling events and transcriptional regulators driving the differentiation of these diverse photoreceptors are currently unknown. Methods: To identify genes specifically expressed in distinct chicken (Gallus gallus) photoreceptor subtypes, we developed fluorescent reporters that label photoreceptor subpopulations, isolated these subpopulations using fluorescence-activated cell sorting, subjected them to next-generation sequencing, and conducted differential expression analysis. Results: We identified hundreds of differentially expressed genes from photoreceptor subpopulations labeled with rhodopsin, red opsin, green opsin, and violet opsin reporters. These genes are involved in a variety of processes, including phototransduction, transcriptional regulation, cell adhesion, maintenance of intra- and extra-cellular structure, and metabolism. Of particular note are a variety of differentially expressed transcription factors, which may drive and maintain photoreceptor diversity, and cell adhesion molecules that may mediate spatial patterning of photoreceptors and act to establish retinal circuitry. Conclusions: These analyses provide a framework for future studies that will dissect the role of these various factors in the differentiation of avian photoreceptor subtypes. Overall design: mRNA expression profiling of 5 pairs of photoreceptor subtypes isolated from chicken retinal explants, 3 replicates per sample
Transcriptome profiling of developing photoreceptor subtypes reveals candidate genes involved in avian photoreceptor diversification.
Specimen part, Subject
View SamplesWe have identified loss of deiminated MA-Brent-1 (an RNA and export binding protein) in the retinal ganglion cells (RGCs) in multiple sclerosis and in glaucoma eyes compared to normal controls. Deimination refers to posttranslational modification of protein bound arginine (not free arginine) in citrulline. Our preliminary studies suggest binding of different repertoire of RNA by non-deiminated and deiminated MA-Brent-1. In vitro, in neurites of cultured RGCs and hippocampal neurons, the select mRNA translation is enhanced by addition of deiminated but not non-deiminated MA-Brent-1. These observations suggest that lack of deiminated MA-Brent-1 has consequences for protein synthesis, remodeling and plasticity of RGCs/neurons. Identification of RNA species bound by deiminated and non-deiminated MA-Brent-1 will enable us there further verification and determining the role that deimination plays in biological function of MA-Brent-1 in multiple sclerosis and glaucoma. To summarize identification of RNA species bound by deiminated and non deiminated MA-Brent-1 will enable us to gain further insight into role of deimination in the overall disease process.
The role of deimination in ATP5b mRNA transport in a transgenic mouse model of multiple sclerosis.
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View SamplesMicroRNAs comprise 1-3% of all vertebrate genes, but their in vivo functions and mechanisms of action remain largely unknown. Zebrafish miR-430 is expressed at the onset of zygotic transcription and regulates morphogenesis during early development. Using a microarray approach and in vivo target validation, we find that miR-430 directly regulates several hundred target mRNAs. Targets are highly enriched for maternal mRNAs that accumulate in the absence of miR-430. We also show that miR-430 accelerates the deadenylation of target mRNAs. These results suggest that miR-430 facilitates the deadenylation and clearance of maternal mRNAs during early embryogenesis.
Zebrafish MiR-430 promotes deadenylation and clearance of maternal mRNAs.
No sample metadata fields
View SamplesPurpose: We aimed to investigate in depth the regulation of microRNA expression by hypoxia in the breast cancer cell line MCF-7, establish the relationship between microRNA expression and HIF binding sites, pri-miRNA transcription and microRNA processing gene expression. Methods: microRNA sequencing data and gene expression microarray data were generated from MCF-7 cells submitted to an hypoxia timecourse (16h, 32h and 48h at 1% Oxygen). Data was integrated to 500 published high-stringency HIF binding sites identified in MCF-7 cells. Results: We identified 41 microRNAs significantly up- and 28 down- regulated, of which 38 mature and 20 star forms are reported in conjunction with hypoxia for the first time. HIF-1a and HIF-2a binding sites within 50kb distance of microRNA loci were found by integration of HIF ChIP-seq data, showing overall association between binding sites and up-regulation. Gene expression profiling analysis showed no full coordination between pri-miRNA and microRNA expression, pointing towards additional levels of regulation. Several transcripts playing a role in microRNA processing were found regulated by hypoxia, of which two were HIF dependent. Conclusions: The data support the hypothesis that microRNA expression under hypoxia is regulated at transcriptional and post-transcriptional level. HIF is involved at both levels, regulating the transcription of certain microRNAs and also the expression of key elements of the microRNA processing pathway. Overall design: microRNA-seq profiles of MCF-7 exposed to hypoxia (1% Oxygen) for 16h (2 replicates), 32h (2 replicates) and 48h (2 replicates) and to normoxia (2 replicates) were generated using Illumina sequencing platform.
Integrated analysis of microRNA and mRNA expression and association with HIF binding reveals the complexity of microRNA expression regulation under hypoxia.
Cell line, Treatment, Subject, Time
View SamplesNPY signalling via osteoblastic Y1 receptors has been shown to control bone mass but also contributes significantly to the control of whole-body insulin secretion and glucose homeostasis in mice through the release of novel factor(s) which are different from the previously implicated osteocalcin.
Osteoglycin, a novel coordinator of bone and glucose homeostasis.
Sex, Specimen part
View SamplesWe compared the performance of conventional RNAseq with RNA Capture Sequencing (CaptureSeq) to assemble and quantify known RNA spike-Ins and human transcripts. We find CaptureSeq to be superior for the detection and quantification of the 37% lowest expressed genes, and comparable for the next 45% of moderately expressed genes. CaptureSeq contributes only minor technical variation and measures differential gene expression accurately. We demonstrate these advantages by the targeted sequencing of long noncoding RNAs across 20 human tissues, expanding previous annotations two-fold and simultaneously generating a quantitative atlas of expression. This analysis confirms the use of CaptureSeq as an important method for transcriptional profiling. Overall design: Long noncoding RNA assembly and expression is analysed by targeted RNA sequencing for 20 human tissues and 4 human cell lines
Quantitative gene profiling of long noncoding RNAs with targeted RNA sequencing.
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View SamplesTo explore the primary cause of Dilated Cardiomyopathy in heart samples from DCM-diagnosed patients who had undergone heart transplant (hDCM), we set out to identify differentially expressed genes by massively parallel sequencing of heart samples. Overall design: Methods: Heart mRNA profiles from DCM-diagnosed patients who had undergone heart transplant (hDCM) were generated by deep sequencing, in triplicate, using Illumina GAIIx.
Bmi1 limits dilated cardiomyopathy and heart failure by inhibiting cardiac senescence.
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View SamplesTo explore the primary cause of Dilated Cardiomyopathy in Bmi1-null mice, we set out to identify differentially expressed genes by massively parallel sequencing of heart samples from Bmi1f/f;aMHCTM-Cretg/+ mice versus aMHCTM-Cretg/+ control mice (17 weeks postinduction). Overall design: Methods: Heart mRNA profiles of 17-weeks post-induction Bmi1f/f; MHCTM-Cretg/+ mice and MHCTM-Cretg/+ control mice were generated by deep sequencing, in triplicate, using Illumina GAIIx. Sequence reads were pre-processed with Cutadapt 1.2.1, to remove TruSeq adapters and mapped on the mouse transcriptome (Ensembl gene-build GRCm38.v70) using RSEM v1.2.3. The Bioconductor package EdgeR was used to normalize data with TMM and to test for differential expression of genes using GLM.
Bmi1 limits dilated cardiomyopathy and heart failure by inhibiting cardiac senescence.
No sample metadata fields
View SamplesComparison of miRNA expression profiles in malignant germ cell tumors compared to non-malignant control group.
Malignant germ cell tumors display common microRNA profiles resulting in global changes in expression of messenger RNA targets.
Sex, Age
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