Biliary atresia (BA) is a rare cholestatic disease of unknown etiology that affects infants and shows an incidence of 1 out of 18,000 live births in Europe (1). The first therapeutic option is a timely performed portoenterostomy. However, the majority of patients suffer from a progressive inflammatory process, which leads to complete destruction of the extra- and intrahepatic biliary system followed by end-stage liver cirrhosis. Hence, BA is the leading indication for pediatric liver transplantation worldwide (2, 3). To understand the pathogenesis of the disease and improve theoutcome of BA patients, research has focused on the inflammatory process in liver and bile ducts, in which several factors are remarkably elevated, such as activated CD4 and CD8 T-cells, TNF alpha,IFN alpha and other proinflammatory TH1 cytokines (3-8). By the time of diagnosis, however, the disease has already reached an advanced state, characterized by the complete obstruction of the extrahepatic bile ducts with impaired bile flow and fibrosis or cirrhosis of the liver. Therefore, studies in humans focusing on the trigger mechanism of BA are limited due to the paucity of liver and availability of bile duct tissue for research. One infectious animal model has been developed, in which newborn Balb/c mice exclusively show the experimental BA phenotype after infection with rhesus rotavirus (RRV) (9, 10). This model allows the analysis of the inflammatory reactions in liver and bile ducts at early steps in the development of bile duct atresia (11-20). Furthermore, inbred mouse strains have been shown to have a different susceptibility for the development of experimental BA, suggesting that Balb/c mice have an immunological gap responsible for disease progression (10, 12). The aim of this study was to identify key genes responsible for the BA phenotype by comparing the transcriptomes at an early time point after virus infection, i.e. before bile duct atresia, between two mouse strains with different susceptibilities to BA. Differences in the virus titration and the clinical course of infected mice were analyzed, and variations in the hepatic gene response assessed by comparative microarray assays were correlated to variances in the hepatic inflammatory reaction.
Susceptibility to experimental biliary atresia linked to different hepatic gene expression profiles in two mouse strains.
Specimen part
View SamplesMost hepatocellular carcinomas in younger patients from Peru arise from non-cirrhotic livers. Histological examination of the non-tumor liver tissues highlights the presence of clear cell foci in a significant fraction of Peruvian patients with hepatocellular carcinoma.
Liver clear cell foci and viral infection are associated with non-cirrhotic, non-fibrolamellar hepatocellular carcinoma in young patients from South America.
Specimen part, Disease stage, Subject
View SamplesDespite widespread use of sunscreens that minimize erythema by blocking ultraviolet B (UVB) radiation, incidence rates of melanoma continue to rise. In considering this disparity between intervention and disease prevalence, we investigated the in vivo transcriptome of human skin treated with sunscreen and solar-simulated radiation (ssR). A focal skin area of healthy participants was exposed to ssR at 1 minimal erythema dose (MED), 0.1 MED or 100 J/m2 with or without prior application of sunscreen, or to non-UVB-spectrum of ssR (solar-simulated UVA/visible/infrared radiation: ssA). Skin biopsies were analyzed using expression microarrays.
Transcriptional signatures of full-spectrum and non-UVB-spectrum solar irradiation in human skin.
Sex, Specimen part
View SamplesHigh expression of the ETS family transcription factor ERG is associated with poor clinical outcome in acute myeloid leukemia (AML) and acute T-cell lymphoblastic leukemia (T-ALL). In murine models, high ERG expression induces both T-ALL and AML. However, no study to date has defined the effect of high ERG expression on primary human hematopoietic cells. In the present study, human CD34+ cells were transduced with retroviral vectors to elevate ERG gene expression to levels detected in high ERG AML. RNA sequencing was performed on purified populations of transduced cells to define the effects of high ERG on gene expression in human CD34+ cells. Integration of the genome-wide expression data with other data sets revealed that high ERG drives an expression signature that shares features of normal hematopoietic stem cells, high ERG AMLs, early T-cell precursor-ALLs and leukemic stem cell signatures associated with poor clinical outcome. Functional assays linked this gene expression profile to enhanced progenitor cell expansion. These results support a model whereby a stem cell gene expression network driven by high ERG in human cells enhances the expansion of the progenitor pool, providing opportunity for the acquisition and propagation of mutations and the development of leukemia. Overall design: RNA sequencing in ERG overexpressing human CD34+ cells
Overexpression of ERG in cord blood progenitors promotes expansion and recapitulates molecular signatures of high ERG leukemias.
No sample metadata fields
View SamplesEfferent inhibition of cochlear outer hair cells is mediated by nicotinic cholinergic receptors containing alpha9 (a9) and alpha10 subunits. Mice lacking a9 nicotinic subunits fail to exhibit classic olivocochlear responses and are characterized by abnormal synaptic morphology at the base of outer hair cells. To detail molecular changes induced upon the loss of a9 subunit, we sampled cochlear RNA from wild type and a9 null mice at postnatal (P) days spanning periods of synapse formation and maturation (P3, P7, P13 and P60). Our findings point to a delay in cochlear maturation starting at the onset of hearing (P13), as well as an up-regulation of various GABA receptor subunits in adult mice lacking the a9 nicotinic subunit.
Lack of nAChR activity depresses cochlear maturation and up-regulates GABA system components: temporal profiling of gene expression in alpha9 null mice.
Specimen part
View SamplesA fundamental challenge in genomics is to map DNA sequence variants onto changes in gene expression. Gene expression is regulated by cis-regulatory elements (CREs, i.e., enhancers, promoters, and silencers) and the trans factors (e.g., transcription factors) that act upon them. A powerful approach to dissecting cis and trans effects is to compare F1 hybrids with F0 homozygotes. Using this approach and taking advantage of the high frequency of polymorphisms in wild-derived inbred Cast/EiJ mice relative to the reference strain C57BL/6J, we conducted allele-specific mRNA-seq analysis in the adult mouse retina, a disease-relevant neural tissue. We found that cis effects account for the bulk of gene regulatory divergence in the retina. Many CREs contained functional (i.e., activating or silencing) cis-regulatory variants mapping onto altered expression of genes, including genes associated with retinal disease. By comparing our retinal data with previously published liver data, we found that most of the cis effects identified were tissue-specific. Lastly, by comparing reciprocal F1 hybrids, we identified evidence of imprinting in the retina for the first time. Our study provides a framework and resource for mapping cis-regulatory variants onto changes in gene expression, and underscores the importance of studying cis-regulatory variants in the context of retinal disease. Overall design: Retinas from four classes of 8 week old male mice were collected: F0 C57BL/6J (B6), F0 Cast/EiJ (Cast), F1 B6xCast, and F1 CastxB6. Three replicates per class were generated. Each replicate consisted of a pool of 6-8 retinas. The mRNA-seq was conducted with paired-end 2x101 sequencing on the Illumina HiSeq 2000 platform. One lane of sequencing was run for all twelve samples. An additional lane of sequencing was run for the six F1 samples.
Hybrid mice reveal parent-of-origin and Cis- and trans-regulatory effects in the retina.
No sample metadata fields
View SamplesThe goals of this study is to test whether NICD presence protects the RBPjk-null Hair Follicles by altering gene expression via association with other DNA binding proteins at P3, just before the conversion to TSLP-producing keratin cysts. Overall design: Methods: Skin samples were embedded in OCT. Sectioned at 20µm thickness. Dehydrated in EtOH, and equilibrated to Xylene before the LCM procedure. Laser capture was performed with Arcturus Veritas. Methods: ~100 hair follicles from Notch-null, PS-null, RBPjk-null and wild-type samples were pooled into 3 biological replicates for each genotype and subjected to RNA isolation followed by RNA-Seq. Conclusions: A total of 2047 genes were differentially expressed (=1.5 fold) in three or more biological replicates of Notch mutant hair follicles compared to wild-type controls (p-value<0.05). Unsupervised hierarchical clustering analysis failed to distinguish between the mutants.
The Notch Intracellular Domain Has an RBPj-Independent Role during Mouse Hair Follicular Development.
Cell line, Subject
View SamplesPolycomb-group proteins form multimeric protein complexes involved in transcriptional silencing. The Polycomb Repressive complex 2 (PRC2) contains the Suppressor of Zeste-12 protein (Suz12) and the histone methyltransferase Enhancer of Zeste protein-2 (Ezh2). This complex, catalyzing the di- and tri-methylation of histone H3 lysine 27, is essential for embryonic development and stem cell renewal. However, the role of Polycomb-group protein complexes in the control of the intestinal epithelial cell (IEC) phenotype is not known. We investigated the impact of Suz 12 depletion on gene expression in IEC-6 cells.
The histone H3K27 methylation mark regulates intestinal epithelial cell density-dependent proliferation and the inflammatory response.
Cell line
View SamplesPURPOSE. To determine global mRNA expression levels in the corneal and conjunctival epithelia and identify transcripts that exhibit preferential tissue expression.
Comparative analysis of human conjunctival and corneal epithelial gene expression with oligonucleotide microarrays.
No sample metadata fields
View SamplesTo systemically explore how RNA quality affects microarray assay results, a set of rat liver RNA samples with a progressive change in RNA quality was generated either by thawing frozen tissue or by ex vivo incubation of fresh tissue.
Characterization of the effect of sample quality on high density oligonucleotide microarray data using progressively degraded rat liver RNA.
Sex, Age, Specimen part, Time
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