Analysis of livers of male and female B6C3F1 mice exposed to prototype treatments from five classes of model hepatotoxicants. These hepatotoxicants include compounds that activate the peroxisome proliferator-activated receptor (PPAR), induce the inflammatory response, activate the constitutive androstane receptor (CAR), stimulate the hypoxia signal transduction pathway, and activate the aryl-hydrocarbon receptor (AHR). The results provide insights into the shared and unique pathways that are activated across these model hepatotoxicants.
Screening a mouse liver gene expression compendium identifies modulators of the aryl hydrocarbon receptor (AhR).
Sex, Age, Compound, Time
View SamplesPPAR-null and wild-type male mice treated with PFHxS or PFNA
Screening a mouse liver gene expression compendium identifies modulators of the aryl hydrocarbon receptor (AhR).
Sex, Specimen part, Compound
View SamplesMany environmentally-relevant chemicals and drugs activate the nuclear receptor pregnane X receptor (PXR). Activation of PXR can lead to increases in liver weight in part through hepatocyte replication similar to a large number of compounds that activate other nuclear receptors such as the peroxisome proliferator-activated receptor alpha and the constitutive activated receptor (CAR). PXR controls the expression of a large battery of genes involved in xenobiotic metabolism. Identification of genes that are accurate predictors of PXR activation would be useful in high-throughput screens to assess potential toxicity and drug-drug interactions. Here, we identified PXR-dependent genes in the mouse liver after exposure to pregnenolone 16alpha-carbinonitrile (PCN), a chemical that is often used as a model PXR agonist.
Screening a mouse liver gene expression compendium identifies modulators of the aryl hydrocarbon receptor (AhR).
Sex, Specimen part, Compound
View SamplesTo study the role of epigenetics and hormones on hematopoietic stem cell function, hematopoietic stem and progenitor (LSK) cells were sorted from E14.5 embryos of wild-type, DNMT3B7 hemizygous or DNMT3B7 homozygous genotype. The expression analysis was performed to provide information regarding the mechanism by which hormones regulate hematopoiesis. Overall design: Hematopoietic stem and progenitor (LSK) cells from E14.5 murine embryonic fetal livers of wild-type, or DNMT3B7 transgenic genotypes were flow-sorted, and RNA isolated for expression analysis by RNA-Sequencing
Epigenetic Control of Apolipoprotein E Expression Mediates Gender-Specific Hematopoietic Regulation.
No sample metadata fields
View SamplesRetinopathy of prematurity (ROP) is the most common cause of childhood blindness worldwide and is caused by oxygen therapy necessary to prevent mortality after premature birth. We have previously demonstrated the efficacy of systemic hypoxia inducible factor (HIF) stabilization through HIF prolyl hydroxylase inhibition (HIF PHi) in protecting retinal vasculature from oxygen toxicity in a mouse model of ROP or oxygen induced retinopathy (OIR). We definitively demonstrated that hepatic HIF-1 can be activated to confer this protection using systemic dimethyloxalylglycine (DMOG) to prevent HIF-1a degradation. In this study we compare Roxadustat, a small molecule stabilizer of HIF-1 currently in phase 3 clinical trials for increasing erythropoiesis in adult patients with chronic kidney disease, to DMOG. We demonstrate that Roxadustat induces vascular protection during hyperoxia to induce the coordinated sequential growth of retinal vasculature with a 3-fold reduction in oxygen induced capillary loss (p-=0.001). In order to define the molecular mechanism of protection, we further compared the transcriptome of both liver and retina after systemic treatment with Roxadustat or DMOG. Similar gene expression profiles were identified in liver but very different effects on transcription were found in retinal tissues because Roxadustat, in contrast to DMOG, directly targets retina, confirmed by western blot and by rescue of the hepatic HIF-1 KO, two criteria that DMOG treatment is unable to fulfill. Systems pharmacologic analysis demonstrates that Roxadustat induces typical HIF regulated genes critical to aerobic glycolysis in liver and retinal tissues whereas DMOG, acting through either secreted hepatokines or by influence of systemic DMOG, downregulates cell adhesion/extracellular matrix interaction pathways while increasing expression of histone cluster genes. Stratification of liver transcriptomes to secreted gene products again shows close consensus of hepatic genes induced by both small molecules, and includes upregulation of a plethora of angiogenic proteins such as plasminogen activator inhibitor (PAI-1), erythropoietin (EPO), and orosomucosoid 2 (ORM2). Secondary validation of these transcripts by serum ELISA confirms secretion of EPO and PAI-1 into blood from liver. These findings definitively demonstrate that HIF stabilization can prevent OIR by two pathways: direct retinal HIF stabilization and induction of aerobic glycolysis or indirect, hepatic HIF-1 stabilization and increased serum angiokines. Systems pharmacology analysis therefore explains why intermittent, low dosage of small molecule HIF stabilizers creates a profound protective phenotype, because both pathways can take advantage of cytoprotection induced by the liver and by retina synergistically. These data provide a rationale for considering low dose, intermittent systemic administration of Roxadustat, currently in phase 3 trials in adults with chronic kidney disease, to eradicate ROP in children. Overall design: RNA-Seq of mice treated with PBS (control), DMOG, or Roxadustat from liver or retina.
Comparative systems pharmacology of HIF stabilization in the prevention of retinopathy of prematurity.
Specimen part, Cell line, Treatment, Subject
View SamplesCytosine methylation is an epigenetic mark usually associated with gene repression. Despite a requirement for de novo DNA methylation for differentiation of embryonic stem cells, its role in somatic stem cells is unknown. Using conditional ablation, we show that loss of either, or both, Dnmt3a or Dnmt3b, progressively impedes hematopoietic stem cell (HSC) differentiation during serial in vivo passage. Concomitantly, HSC self-renewal is immensely augmented in absence of either Dnmt3, particularly Dnmt3a. Dnmt3-KO HSCs show upregulation of HSC multipotency genes and downregulation of early differentiation factors, and the differentiated progeny of Dnmt3-KO HSCs exhibit hypomethylation and incomplete repression of HSC-specific genes. HSCs lacking Dnmt3a manifest hyper-methylation of CpG islands and hypo-methylation of genes which are highly correlated with human hematologic malignancies. These data establish that aberrant DNA methylation has direct pathologic consequences for somatic stem cell development, leading to inefficient differentiation and maintenance of a self-renewal program.
Dnmt3a is essential for hematopoietic stem cell differentiation.
Sex, Specimen part
View SamplesGene expression profiling of in vitro differentiated murine Th cell subsets. Flow cytometrically sorted naive Th cells (CD4+ CD44- Foxp3-) were polyclonally stimulated in vitro for 3 days using 4 g/ml plate-bound antibody to CD3 (145-2C11) and 2 g/ml soluble antibody to CD28 (PV-1).
IL-27 and IL-12 oppose pro-inflammatory IL-23 in CD4+ T cells by inducing Blimp1.
Specimen part
View SamplesThe cholecystokinin B (2) receptor knockout (Cckbr KO) protects against allodynia induced by chronic constriction injury (CCI). The mechanism of this phenomenon is unknown, but must involve persistent changes in pain modulation and/or inflammatory pathways. We performed a gene expression study in two brain areas (midbrain and medulla) after surgical induction of CCI in Cckbr KO and wild-type (wt) control mice. The patterns of gene expression differences suggest that the immune system is activated in higher brain structures following CCI in the wt mice. The strongest differences include genes related to the MAPK pathway activation and cytokine production. In Cckbr KO mice this expressional pattern was absent. In addition, we found significant elevation of the Toll-like receptor 4 (Tlr4) in the supraspinal structures of the mice with deleted Cckbr compared to wt control mice. This up-regulation is most likely induced by the deletion of Cckbr. We suggest that there is a functional deficiency in the Tlr4 pathway which disables the development of neuropathic pain in Cckbr KO mice. Indeed, real time PCR analysis detected a CCI-induced upregulation of Tlr4 and Il1b expression in the lumbar region of wt but not Cckbr KO mice. Gene expression profiling indicates that elements of the immune response are not activated in Cckbr KO mice following CCI. Our findings suggest that there may be a role for CCK in the regulation of innate immunity.
Gene expression profiling reveals upregulation of Tlr4 receptors in Cckb receptor deficient mice.
No sample metadata fields
View SamplesNatural killer T (NKT) cells identified by CD1d-tetramer and TCRb were isolated from the thymi of wild type and Ezh2 knockout mice. The NKT cells were FACS sorted into different stages based on the surface expression of CD44 and NK1.1. Overall design: For both wildtype and knockout mice, RNA was extracted from two biological replicates of CD44+ NK1.1- cells, one replicate of CD44+ NK1.1+ cells and one replicate of CD44- NK1.1- cells. Each RNA sample was divided into four and sequenced on four lanes of an Illumina HiSeq sequencer.
A non-canonical function of Ezh2 preserves immune homeostasis.
Specimen part, Subject
View SamplesIn adult cancers, epigenetic changes and aberrant splicing of the DNMT3B is commonly observed, and the pattern of gene methylation and expression has been shown to be modified by DNMT3B7, a truncated protein of DNMT3B. Much less is known about the mechanism of epigenetic changes in the pediatric cancer neuroblastoma. To investigate if aberrant DNMT3B transcripts alter DNA methylation, gene expression and tumor phenotype in neuroblastoma, we measured DNMT3B isoform expression in primary tumors and cell lines. Higher levels of DNMT3B7 were detected in differentiated ganglioneuroblastomas compared to undifferentiated neuroblastomas, suggesting that expression of DNMT3B7 may induce a less clinically aggressive tumor phenotype. To test this hypothesis, we investigated the effects of forced DNMT3B7 in neuroblastoma cells. We found that DNMT3B7 expression significantly inhibited neuroblastoma cell proliferation in vitro, and in neuroblastoma xenografts, DNMT3B7 decreased angiogenesis and tumor growth. DNMT3B7-positive cells had higher levels of total genomic methylation, and RNA-sequencing revealed a dramatic decrease in expression of FOS and JUN family members, AP1 complex components. Consistent with the established antagonistic relationship between AP1 expression and retinoic acid receptor activity, decreased proliferation and increased differentiation was seen in the DNMT3B7-expressing neuroblastoma cells following treatment with all trans retinoic acid (ATRA) compared to controls. Our results demonstrate that high levels of DNMT3B7 modify the epigenome in neuroblastoma cells, induce changes in gene expression, inhibit tumor growth, and increase sensitivity to ATRA. Further knowledge regarding mechanisms by which DNMT3B7 regulates gene methylation may ultimately lead to the development of therapeutic strategies that reverse the epigenetic aberrations that drive neuroblastoma pathogenesis. Overall design: DNMT3B7, a truncated DNMT3B isoform, was stably transfected into an N-type neuroblastoma cell line (LA1-55n) using a Tet-off inducible system. DNMT3B7 expressing cells were compared to vector control cells after 21 days of induction.
Truncated DNMT3B isoform DNMT3B7 suppresses growth, induces differentiation, and alters DNA methylation in human neuroblastoma.
Cell line, Subject
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