Analysis of the gene signature of steatosis associated to obesity in hepatocytes of Zucker fa/fa obese rats and their controls; identifying target genes linked to steatosis progression. or Obesity and insulin resistance-associated steatosis can be a non-inflammatory condition affecting hepatocytes or progress to steatohepatitis: a condition that can result in end-stage liver disease. Although molecular events leading to accumulation of lipid droplets in the liver have been identified individually, the complexity of the condition suggested that emergent target would be uncovered by a more comprehensive examination. Then, this study was aimed at establishing a gene signature of steatosis in hepatocytes and at identifying target genes linked to steatosis progression. Using Affymetrix oligonucleotide arrays, we compared transcriptomes of hepatocytes isolated from Zucker "fa/fa" obese rats with three different age-related grades of steatosis with those of their counterpart non-steatotic cells.
A subset of dysregulated metabolic and survival genes is associated with severity of hepatic steatosis in obese Zucker rats.
Sex, Age, Specimen part, Disease, Disease stage
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Metabolomic Identification of Subtypes of Nonalcoholic Steatohepatitis.
Age, Specimen part, Treatment
View SamplesMethionine adenosyltransferase (MAT) enzymes generate SAMe (S-adenosylmethionine), the main biological methyl donor. There are two MAT encoding genes in mammals (Mat1a and Mat2a), which show different activities and cellular distribution. Mat1a encodes the enzyme mainly expressed in normal liver. Mat1a ablation in mice results in the spontaneous development of non-alcoholic steatohepatitis (NASH). We observed that SAMe depletion in Mat1a KO mice had three main effects on hepatic lipid metabolism: 1) impaired TG (triglyceride) export via VLDL; 2) impaired mitochondrial FA (fatty acid) oxidation (as evidenced by membrane depolarization, downregulation of Phb1 (prohibitin 1, a mitochondrial chaperone protein) and Mcj/Dnajc15 (endogenous mitochondrial repressor of respiratory chain), and accumulation of long-chain acylcarnitines); and 3) increased FA uptake. The convergence of these three factors induced TG accumulation in LD (lipid droplets). LD expansion confronts hepatocytes with a high demand of PC (phosphatidylcholine) molecules to cover the LD surface since other phospholipids, such as PE (phosphatidylethanolamine), cannot stabilize LD and prevent coalescence. In Mat1a KO this situation is aggravated, since SAMe-dependent PC synthesis via PE methylation is decreased, the PC/PE ratio reduced and mitochondrial FA oxidation impaired. To put a brake to this drain of PC molecules to LD, FA are rerouted in Mat1a KO mice liver to other catabolic (endoplasmic reticulum and peroxisome oxidation) and biosynthetic (ceramides synthesis) pathways, causing oxidative stress, inflammation and fibrosis. SAMe treatment for two months in 8-9 month old Mat1a KO mice ameliorated mitochondrial dysfunction (reduces membrane depolarization, improves Phb1 and Mcj expression, and increases SAMe transport to mitochondria) improving FA oxidation efficiency (FA and acylcarnitine levels decrease), which results in a drastic reduction in TG accumulation. SAMe treatment in Mat1a KO mice resulted in more PC available for proper membrane function, improving liver lipid homeostasis, histology (H&E, Sudan red, Sirius red) and liver injury (ALT, AST).
Metabolomic Identification of Subtypes of Nonalcoholic Steatohepatitis.
Age, Specimen part
View SamplesThe present study was designed to identify Mkl1 target genes whose expression requires either the B1 site of Mkl1 and serum response factor (SRF), respectively, or the SAP domain of Mkl1. For this purpose, we obtained the transcriptomes of four stable 4T1 cell lines that either overexpress full length Mkl1-RFP (4T1-FL), Mkl1-RFP with a mutated SRF-interaction site (4T1-mutB1), Mkl1-RFP with a deletion of the SAP domain (4T1-SAP) or an empty vector encoding RFP alone (4T1 control).
Mechanism of irradiation-induced mammary cancer metastasis: A role for SAP-dependent Mkl1 signaling.
Specimen part, Cell line
View SamplesThe present study was designed to identify genes induced by irradiation in the 4T1 breast cancer model mimicking aggressive local relapse after radiotherapy. For this purpose, we obtained the transcriptomes of 4T1 tumors grown in either preirradiated (IRR+4T1) or non-irradiated (4T1) mammary tissue.
Mechanism of irradiation-induced mammary cancer metastasis: A role for SAP-dependent Mkl1 signaling.
Specimen part
View SamplesAnalysis of different iPSC clones in comparison to parental fibroblasts and Pluripotent ESC and iPSC lines
CD44 is a negative cell surface marker for pluripotent stem cell identification during human fibroblast reprogramming.
Cell line
View SamplesWe have previously shown that HC11 mammary epithelial cells react strongly to the overexpression of megakaryoblastic leukemia-1 (Mkl1) with induction of tenascin-C expression. The present study was designed to find genes co-regulated with tenascin-C by Mkl1 in a SAP domain-dependent manner and without the involvement of serum response factor (SRF). For this purpose, we compared the transcriptomes of three stable HC11 cell strains that either overexpress full length Mkl1-RFP (HC11-FL), Mkl1-RFP with a mutated SRF-interaction site (HC11-mutB1) or Mkl1-RFP with a deletion of the SAP domain (HC11-SAP).
SAP domain-dependent Mkl1 signaling stimulates proliferation and cell migration by induction of a distinct gene set indicative of poor prognosis in breast cancer patients.
Specimen part
View SamplesTranscription and pre-mRNA alternative splicing are highly regulated processes that play major roles in modulating eukaryotic gene expression. It is increasingly apparent that other pathways of RNA metabolism, including small RNA biogenesis, can regulate these processes. However, a direct link between alternative pre- mRNA splicing and small RNA pathways has remained elusive. Here we show that the small RNA pathway protein Argonaute-2 (Ago-2) regulates alternative pre-mRNA splicing patterns of specific transcripts in the Drosophila nucleus using genome-wide methods in conjunction with RNAi in cell culture and Ago-2 deletion or catalytic site mutations in Drosophila adults. Moreover, we show that nuclear Argonaute-2 binds to specific chromatin sites near gene promoters and negatively regulates the transcription of the Ago-2-associated target genes. These transcriptional target genes are also bound by Polycomb group (PcG) transcriptional repressor proteins and change during development, implying that Ago-2 may regulate Drosophila development. Impor- tantly, both of these activities were independent of the catalytic activity of Ago-2, suggesting new roles for Ago-2 in the nucleus. Finally, we determined the nuclear RNA-binding profile of Ago-2, found it bound to several splicing target transcripts, and identified a G-rich RNA-binding site for Ago-2 that was enriched in these transcripts. These results suggest two new nuclear roles for Ago-2: one in pre-mRNA splicing and one in transcriptional repression. Overall design: 2 Ago2 mutants, 51B and V966M, heterozygotes and homozygotes of both each sequenced in duplicate
Two new and distinct roles for Drosophila Argonaute-2 in the nucleus: alternative pre-mRNA splicing and transcriptional repression.
Sex, Subject
View SamplesSV7tert AML cells were obtained from ATCC and cultured in Dulbecco's modified essential medium (DMEM), glutamine (4mmol) and 10% foetal bovine serum (FBS). Two million SV7tertAML cells were subcutaneously injected into nude mice either with or without subcutaneous oestrogen pellets (n=4 per group); oestrogen was added using 0.36mg 60 day release oestrogen pellets implanted sub-cutaneously. Mice were housed in pathoflex isolators at 26C, on 12 hour light / dark cycles. Irradiated RB2 diet and autoclaved water provided ad libertum.
Analysis of the oestrogen response in an angiomyolipoma derived xenograft model.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
The Cancer Cell Line Encyclopedia enables predictive modelling of anticancer drug sensitivity.
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