TGR5 (Gpbar1) is a G protein-coupled receptor responsive to bile acids (BAs), which is expressed in different non-parenchymal cells of the liver, including biliary epithelial cells, liver-resident macrophages, sinusoidal endothelial cells (LSECs) and activated hepatic stellate cells (HSCs). Mice with targeted deletion of TGR5 are more susceptible towards cholestatic liver injury induced by cholic acid-feeding and bile duct ligation, resulting in a reduced proliferative response and increased liver injury. Conjugated lithocholic acid (LCA) represents the most potent TGR5 BA ligand and LCA-feeding has been used as a model to rapidly induce severe cholestatic liver injury in mice. Thus, TGR5 knockout (KO) mice and wildtype littermates were fed a diet supplemented with 1%LCA for 84 hours. Liver injury and gene expression changes induced by the LCA-diet revealed an enrichment of pathways associated with inflammation, proliferation and matrix remodelling. Knockout of TGR5 in mice caused upregulation of endothelin-1 (ET-1) expression in the livers. Analysis of TGR5-dependent ET-1 signalling in isolated LSECs and HSCs demonstrated that TGR5 activation reduces ET-1 expression and secretion from LSECs and triggers internalization of the ET-1 receptor in HSCs dampening ET-1 responsiveness. Thus, we identified two independent mechanisms by which TGR5 inhibits ET-1 signalling and modulates portal pressure.
The G Protein-Coupled Bile Acid Receptor TGR5 (Gpbar1) Modulates Endothelin-1 Signaling in Liver.
Sex
View SamplesThis SuperSeries is composed of the SubSeries listed below.
SUMOylation-dependent LRH-1/PROX1 interaction promotes atherosclerosis by decreasing hepatic reverse cholesterol transport.
Specimen part
View SamplesTranscript data from LRH-1 WT and LRH-1 K289R jejunums from mice fed ad libitum and sacrificed at 7 am
SUMOylation-dependent LRH-1/PROX1 interaction promotes atherosclerosis by decreasing hepatic reverse cholesterol transport.
Specimen part
View SamplesHypermethylation of tumor suppressor gene (TSG) promoters confers growth advantages to cancer cells, but how these changes arise is poorly understood. Here, we report that tumor hypoxia reduces the activity of oxygen-dependent TET enzymes, which catalyze DNA de-methylation through 5-methylcytosine oxidation. This occurs independently of hypoxia-associated alterations in TET gene expression, basal metabolism, HIF activity or nuclear reactive oxygen species, but directly depends on oxygen shortage. Hypoxia-induced loss of TET activity increases hypermethylation at gene promoters in vitro, while also in patients, gene promoters are markedly more methylated in hypoxic than normoxic tumors. Affected genes are frequently involved in DNA repair, cell cycle regulation, angiogenesis and metastasis, indicating cellular selection of hypermethylation events. Overall, up to 50% of the tumor-associated hypermethylation is ascribable to hypoxia across various cancer types. Accordingly, spontaneous murine breast tumors become hypermethylated when rendered hypoxic through vessel pruning, whereas vessel normalisation rescues this effect. Tumor hypoxia thus acts as a novel regulator underlying DNA methylation. Overall design: RNAseq of MCF7 cells grown under hypoxic and normoxic conditions. Submission includes data on 5 independent RNAseq experiments, each containing biological replicates grown under hypoxic conditions (0.5% oxygen), and under normoxic conditions.
Tumour hypoxia causes DNA hypermethylation by reducing TET activity.
Subject
View SamplesTissue-specific differentiation and inflammatory programmes are thought to independently contribute to disease. The orphan nuclear receptor NR5A2 is a key regulator of pancreas differentiation, and SNPs in and near the human gene are associated with risk of pancreatic cancer. In mice, Nr5a2 heterozygosity sensitizes the pancreas to damage, impairs regeneration, and cooperates with mutant Kras in tumor progression. Through transcriptomic analysis, we uncovered a basal pre-inflammatory state in the pancreas of heterozygous mice that is reminiscent of pancreatitis-induced inflammation and is conserved in histologically normal human pancreata with reduced Nr5a2 mRNA expression. In mice, Nr5a2 undergoes a dramatic transcriptional switch from tissue-specific to inflammatory loci, which promotes AP-1-dependent inflammatory gene transcription. Deletion of c-Jun in the pancreas of Nr5a2+/- mice rescues the pre-inflammatory phenotype and the defective regenerative response to damage. These findings provide compelling evidence that the same transcriptional networks supporting homeostasis in normal tissue can be subverted to foster inflammation upon genetic or environmental constraints. Overall design: A mild acute pancreatitis was induced by seven hourly injections of the CCK analog caerulein (Bachem) at 50 ug/kg. Briefly, animals were weighted before the beginning of the procedure and caerulein was administered i.p. Mice were sacrificed by cervical dislocation 8h, 24h,and 48h after the first injection. Three animals of each genotype and timepoint were analysed.
Transcriptional regulation by NR5A2 links differentiation and inflammation in the pancreas.
Specimen part, Treatment, Subject
View SamplesThis SuperSeries is composed of the SubSeries listed below.
LRH-1 agonism favours an immune-islet dialogue which protects against diabetes mellitus.
Age, Specimen part, Treatment
View SamplesStrategy to repress autoimmunity and promote islet beta cell regeneration
LRH-1 agonism favours an immune-islet dialogue which protects against diabetes mellitus.
Age, Specimen part, Treatment
View SamplesTo gain insight in the kinetics and interplay of the predominant transcriptional responses of DNA damage signalling pathways in undifferentiated cells, mouse embryonic stem cells were exposed to cisplatin at four different time points (2, 4, 8 and 24 hr) and concentrations (1, 2, 5 and 10 uM). RNA was isolated and subjected to genome-wide expression profiling.
A portrait of cisplatin-induced transcriptional changes in mouse embryonic stem cells reveals a dominant p53-like response.
Specimen part, Compound, Time
View SamplesType II testicular germ cell cancers (GCC) are the most frequently diagnosed tumors in young men (20 - 40 years) and are classified as seminoma or non-seminoma. GCCs are commonly treated by orchiectomy and chemo- or radiotherapy. However, a subset of metastatic non-seminomas display only incomplete remission or relapse and require novel treatment options. Recent studies have shown effective application of the small-molecule inhibitor JQ1 in tumor therapy, which interferes with the function of bromodomain and extra-terminal (BET)-proteins. Here, we demonstrate that upon JQ1 doses 250 nM GCC cell lines and Sertoli cells display compromised survival and induction of cell cycle arrest. JQ1 treated GCC cell lines display upregulation of genes indicative for DNA damage and a cellular stress response. Additionally, downregulation of pluripotency factors and induction of mesodermal differentiation was detected. GCCs xenografted in vivo showed a reduction in tumor size, proliferation and angiogenesis when subjected to JQ1 treatment. The combination of JQ1 and the histone deacetylase inhibitor romidepsin further enhanced the apoptotic effect in vitro and in vivo. Thus, we propose that JQ1 alone, or in combination with romidepsin may serve as a novel therapeutic option for GCCs.
The bromodomain inhibitor JQ1 triggers growth arrest and apoptosis in testicular germ cell tumours in vitro and in vivo.
Specimen part, Cell line, Time
View SamplesMaintenance and maturation of primordial germ cells is controlled by complex genetic and epigenetic cascades, and disturbances in this network lead to either infertility or malignant aberration. Transcription factor Tcfap2c / TFAP2C has been described to be essential for primordial germ cell maintenance and to be upregulated in several human germ cell cancers. Using global gene expression profiling, we identified genes deregulated upon loss of Tcfap2c in primordial germ cell-like cells. We show that loss of Tcfap2c affects many aspects of the genetic network regulating germ cell biology, such as downregulation maturation markers and induction of markers indicative of somatic differentiation, cell cycle, epigenetic remodeling, and pluripotency associated genes. Chromatin-immunoprecipitation analyses demonstrated binding of Tcfap2c to regulatory regions of deregulated genes (Sfrp1, Dmrt1, Nanos3, c-Kit, Cdk6, Cdkn1a, Fgf4, Klf4, Dnmt3b and Dnmt3l) suggesting that these genes are direct transcriptional targets of Tcfap2c in primordial germ cells. Since Tcfap2c deficient primordial germ cell like cells display cancer related deregulations in epigenetic remodeling, cell cycle and pluripotency control, the Tcfap2c-knockout allele was bred onto 129S2/Sv genetic background. There, mice heterozygous for Tcfap2c develop germ cell cancer with high incidence. Precursor lesions can be observed as early as E16.5 in developing testes displaying persisting expression of pluripotency markers. We further demonstrate, that mice with a heterozygous deletion of the Tcfap2c target gene Nanos3 are also prone to develop teratoma. These data highlight Tcfap2c as a critical and dose-sensitive regulator of germ cell fate.
Transcription factor TFAP2C regulates major programs required for murine fetal germ cell maintenance and haploinsufficiency predisposes to teratomas in male mice.
Specimen part
View Samples