Gene expression from bone-marrow drived macrophages of WT and SREBP-1a deficient mice
Linking lipid metabolism to the innate immune response in macrophages through sterol regulatory element binding protein-1a.
No sample metadata fields
View SamplesTo adapt the lives of organisms to the day-night cycle, evolution has built a complex machinery, whose molecular components are able to anticipate and drive changes in organism behavior and metabolism. A mutual bidirectional interaction exists between circadian abnormalities and development of diseases.
Circadian clock regulates the host response to Salmonella.
Age, Specimen part
View SamplesPluripotent stem cells are derived from culture of early embryos or the germline, and can be induced by reprogramming of somatic cells. Barriers to reprogramming are expected to exist that stabilize the differentiated state and have tumor suppression functions. However, we have a limited understanding of what such barriers might be. To find novel barriers to reprogramming to pluripotency, we compared the transcriptional profiles of the mouse germline to pluripotent and somatic cells, in vivo and in vitro. There is a remarkable global expression of the transcriptional program for pluripotency in Primordial Germ Cells (PGCs). We identify parallels between PGCs reprogramming to pluripotency and human germ cell tumorigenesis, including the loss of LATS2, a tumor suppressor kinase of the Hippo pathway. We show that knockdown of LATS2 increases the efficiency of induction of pluripotency in human cells. LATS2 RNAi, unlike p53 RNAi, specifically enhances the generation of fully reprogrammed iPS cells without accelerating cell proliferation. We further show that LATS2 represses reprogramming in human cells by post-transcriptionally antagonizing TAZ but not YAP, two downstream effectors of the Hippo pathway. These results reveal transcriptional parallels between germ cell transformation and the generation of iPS cells, and indicate that the Hippo pathway constitutes a barrier to cellular reprogramming.
Transcriptional analysis of pluripotency reveals the Hippo pathway as a barrier to reprogramming.
Sex, Specimen part
View SamplesWe have recently shown a remarkable regenerative capacity of the prenatal heart using a genetic model of mosaic mitochondrial dysfunction in mice. This model is based on inactivation of the X-linked gene encoding holocytochrome c synthase (Hccs) specifically in the developing heart. Loss of HCCS activity results in respiratory chain dysfunction, disturbed cardiomyocyte differentiation and reduced cell cycle activity. The Hccs gene is subjected to X chromosome inactivation, such that in females heterozygous for the heart conditional Hccs knockout approximately 50% of cardiac cells keep the defective X chromosome active and develop mitochondrial dysfunction while the other 50% remain healthy. During heart development, however, the contribution of HCCS deficient cells to the cardiac tissue decreases from 50% at midgestation to 10% at birth. This regeneration of the prenatal heart is mediated by increased proliferation of the healthy cardiac cell population, which compensate for the defective cells and allow the formation of a fully functional heart at birth. Here we performed microarray expression ananlyses on 13.5 dpc control and heterozygous Hccs knockout hearts to identify molecular mechanisms that drive embryonic heart regeneration.
Embryonic cardiomyocytes can orchestrate various cell protective mechanisms to survive mitochondrial stress.
Sex, Specimen part
View SamplesTranscriptome of murine testis from wild type mice and mice lacking telomerase for three generations (G3-Terc), Ku86 or both telomerase and Ku86.
Effectors of mammalian telomere dysfunction: a comparative transcriptome analysis using mouse models.
No sample metadata fields
View SamplesWhe embryonic stem cells are in vitro expanded threir telomereres lengthen, in the absence of genetic manipulations, concomitant with the loss of heterochromatic marks. In order to analyze whether there would be changes in gene expression during in vitro expansion we performed RNA-seq and found no substantial differences in gene expression at passage 6 or 16. Overall design: Embryonic stem (ES) cells were derived from blastocysts expressing GFP in the Rosa26 locus. Four independent lines of ES were in vitro expanded to passage 16. Total RNA was extracted from each independent clones, RNA was extracted and prepared for RNA-seq.
Generation of mice with longer and better preserved telomeres in the absence of genetic manipulations.
Specimen part, Cell line, Treatment, Subject
View SamplesRecent studies suggest that telomerase promotes cell growth by mechanisms that extend beyond the rescue of critically short telomeres. The in vitro model of mTert overexpressing MEFs recapitulates fundamental aspects of the growth-promoting effects of mTert in vivo. First, in Terc-proficient cells, mTert overexpression favors escape from replicative senescence and enhances anchorage-independent growth in response to oncogenic stress, which fits well with previous data showing that mTert overexpression promotes tumor formation. Second, in Terc-deficient cells, retroviral transduction with mTert results in a delayed onset of immortalization and impairs colony formation in response to oncogenic stress, which is in agreement with the inhibitory effect of mTert overexpression on tumorigenesis in a Terc null mouse background. To unravel the molecular targets of telomerase that impact on cell growth, we compared the transcriptome of MEFs, before and after mTert introduction. We found that ectopic expression of mTert was associated with detectable gene expression changes (greater than 1.5-fold; validated by qRT-PCR) of 26 transcripts. Analysis of the observed transcriptional changes indicates that ectopic expression of mTert suppresses in a coordinated manner functionally related genes with overlapping roles in growth arrest, resistance to transformation, and apoptosis. We show that the majority of the telomerase target genes are growth-inhibitory, transforming growth factor-beta (TGF-beta) -inducible genes and provide functional evidence for the potential of telomerase to abrogate TGF-beta -mediated growth inhibition. Thus, in line with the current view that the diversity of TGF-beta responses is not so much a consequence of the use of different signaling pathways but caused by different ways of reading the output from the same basic pathway, we propose that the telomerase status of a cell creates a gene expression pattern that determines how cells read growth inhibitory signals, among them signals propagated through the TGF-beta pathway.
Expression of mTert in primary murine cells links the growth-promoting effects of telomerase to transforming growth factor-beta signaling.
No sample metadata fields
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Vitamin C induces Tet-dependent DNA demethylation and a blastocyst-like state in ES cells.
Specimen part, Treatment, Time
View SamplesDNA methylation is a heritable epigenetic modification involved in gene silencing, imprinting, and the suppression of retrotransposons. Global DNA demethylation occurs in the early embryo and the germline and may be mediated by Tet (ten-eleven-translocation) enzymes, which convert 5-methylcytosine (mC) to 5-hydroxymethylcytosine (hmC). Tet enzymes have been extensively studied in mouse embryonic stem (ES) cells, which are generally cultured in the absence of Vitamin C, a potential co-factor for Fe(II) 2-oxoglutarate dioxygenase enzymes like Tets. Here we report that addition of Vitamin C to ES cells promotes Tet activity leading to a rapid and global increase in hmC. This is followed by DNA demethylation of numerous gene promoters and up-regulation of demethylated germline genes. Tet1 binding is enriched near the transcription start site (TSS) of genes affected by Vitamin C treatment. Importantly, Vitamin C, but not other antioxidants, enhances the activity of recombinant human Tet1 in a biochemical assay and the Vitamin C-induced changes in hmC and mC are entirely suppressed in Tet1/2 double knockout (Tet DKO) ES cells. Vitamin C has the strongest effects on regions that gain methylation in cultured ES cells compared to blastocysts and in vivo are methylated only after implantation. In contrast, imprinted regions and intracisternal A-particle (IAP) elements, which are resistant to demethylation in the early embryo, are resistant to Vitamin C-induced DNA demethylation. Collectively, this study establishes that Vitamin C is a direct regulator of Tet activity and DNA methylation fidelity in ES cells.
Vitamin C induces Tet-dependent DNA demethylation and a blastocyst-like state in ES cells.
Specimen part
View SamplesWe profiled total mRNA of pancreas and kidney tissues of 3 different strains (p53-null; In4a/Arf-null and WT) of reprogrammable mouse lines (they all express OCT4, SOX2, KLF4, C-MYC under the control of a tetracycline promoter, activated by doxycycline) Overall design: 5 mice of each genotype were treated with doxycycline to induce the expression of the reprogramming factors, they were sacrificed and total mRNA was extracted from pancreas and kidney tissues (we mapped >24M reads per sample)
Tissue damage and senescence provide critical signals for cellular reprogramming in vivo.
Specimen part, Cell line, Subject
View Samples