Background: Studies in mice have shown that PPAR is an important regulator of lipid metabolism in liver and a key transcription factor involved in the adaptive response to fasting. However, much less is known about the role of PPAR in human liver. Here we set out to study the function of PPAR in human liver via analysis of whole genome gene regulation in human liver slices treated with the PPAR agonist Wy14643.
The impact of PPARĪ± activation on whole genome gene expression in human precision cut liver slices.
Sex, Specimen part, Treatment, Subject, Time
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Role of p53 serine 46 in p53 target gene regulation.
Specimen part, Cell line, Compound
View SamplesThe tumor suppressor p53 plays a crucial role in cellular growth control inducing a plethora of cellular response pathways. The molecular mechanisms that discriminate between the distinct p53-responses towards different stress treatments have remained largely elusive. Here, we have analyzed the p53-regulated pathways induced by two chemotherapeutical treatments, Actinomycin D inducing growth arrest and Etoposide resulting in apoptosis. We found that the genome-wide p53-binding patterns are almost identical upon both treatments notwithstanding transcriptional differences that we observed in genome-wide transcriptome analysis. To assess the role of post-translational modifications in target gene choice and activation we investigated the extent of phosphorylation of Serine 46 of p53 bound to DNA (p53-pS46), a modification that has been linked to apoptosis-pathways, and the extent of phosphorylation of Serine 15 (p53-pS15), a general p53-activation mark. Interestingly, the overall extent of S46 phosphorylation of p53 bound to DNA is considerably higher in cells directed towards apoptosis while the degree of phosphorylation at S15 of DNA bound p53 remains highly similar upon both treatments. Moreover, our data suggest that, following different chemotherapeutical treatments, the extent of chromatin-associated p53 phosphorylated at S46 but not at pS15 is higher on certain apoptosis related target genes, including the BAX and PUMA genes. These data provide evidence that cell fate decisions are not made primarily on the level of general p53 DNA-binding, but possibly through post-translational modifications of chromatin bound p53.
Role of p53 serine 46 in p53 target gene regulation.
Specimen part, Cell line
View SamplesEmbryonic stem cells (ESCs) cells run a self-renewal gene expression program, requiring the expression of certain transcription factors accompanied by a particular chromosome organization to maintain a balance between pluripotency and the capacity for rapid differentiation. However, how transcriptional regulation is linked to chromosome organization in ESCs remains enigmatic. Here we show that Cohesin exhibits a functional role in maintaining ESC identity through association with the pluripotency transcriptional network. ChIP-seq analyses of the cohesin subunit Rad21 reveal an ESC specific cohesin binding pattern that is characterized by a CTCF independent colocalization of cohesin with pluripotency related transcription factors. Upon ESC differentiation, these binding sites disappear and instead new CTCF independent Rad21 binding sites emerge, which are enriched for binding sites of transcription factors implicated in early differentiation. Furthermore, knock-down of cohesin subunits causes expression changes that are reminiscent of the depletion of key pluripotency transcription factors, demonstrating the functional relevance of the cohesin - pluripotency transcriptional network association. Finally, we show that Nanog physically interacts with the cohesin interacting proteins Stag1 and Wapl, further substantiating this association. Based on these findings we propose that a dynamic placement of cohesin by pluripotency transcription factors contributes to a chromosome organization supporting the ESC expression program.
RAD21 cooperates with pluripotency transcription factors in the maintenance of embryonic stem cell identity.
Specimen part
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Drug-induced histone eviction from open chromatin contributes to the chemotherapeutic effects of doxorubicin.
Age, Specimen part, Cell line, Treatment, Time
View SamplesOne major class of anti-cancer drugs targets topoisomerase II to induce DNA double-strand breaks and cell death of fast growing cells. In vitro experiments showed that doxorubicin can induce histone eviction as well as DNA damage, while etoposide can only induce DNA damage. Here, we compare the transcription responses of different tissues to doxorubicin or etoposide treatment in vivo.
Drug-induced histone eviction from open chromatin contributes to the chemotherapeutic effects of doxorubicin.
Age, Specimen part, Treatment, Time
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Gene expression profiling in human precision cut liver slices in response to the FXR agonist obeticholic acid.
Sex, Specimen part, Treatment, Subject, Time
View SamplesBackground: The bile acid-activated farnesoid X receptor (FXR) is a nuclear receptor regulating bile acid, glucose and cholesterol homeostasis. Obeticholic acid (OCA; also known as INT-747 or 6-ethyl-chenodeoxycholic acid), a promising drug for the treatment of non-alcoholic steatohepatitis (NASH) and type 2 diabetes, activates FXR. Mouse studies demonstrated that FXR activation by OCA (INT-747) alters hepatic expression of many genes. However, no data are available on the effects of OCA in human liver. Here, we generated gene expression profiles in human precision-cut liver slices (hPCLS) after treatment with OCA.
Gene expression profiling in human precision cut liver slices in response to the FXR agonist obeticholic acid.
Sex, Specimen part, Treatment, Time
View SamplesBackground: The bile acid-activated farnesoid X receptor (FXR) is a nuclear receptor regulating bile acid, glucose and cholesterol homeostasis. Obeticholic acid (OCA; also known as INT-747 or 6-ethyl-chenodeoxycholic acid), a promising drug for the treatment of non-alcoholic steatohepatitis (NASH) and type 2 diabetes, activates FXR. Mouse studies demonstrated that FXR activation by OCA (INT-747) alters hepatic expression of many genes. However, no data are available on the effects of OCA in human liver. Here, we generated gene expression profiles in human precision-cut liver slices (hPCLS) after treatment with OCA.
Gene expression profiling in human precision cut liver slices in response to the FXR agonist obeticholic acid.
Sex, Specimen part, Treatment, Subject, Time
View SamplesCone photoreceptors are specialised sensory retinal neurons responsible for photopic vision, colour perception and visual acuity. Retinal degenerative diseases are a heterogeneous group of eye diseases in which the most severe vision loss typically arises from cone photoreceptor dysfunction or degeneration. Establishing a method to purify cone photoreceptors from retinal tissue can accelerate the identification of key molecular determinants that underlie cone photoreceptor development, survival and function. The work herein describes a new method to purify enhanced green fluorescent protein (EGFP)-labelled cone photoreceptors from adult retina of Tg(3.2TCP:EGFP) zebrafish. Electropherograms confirmed downstream isolation of high-quality RNA with RNA integrity number (RIN) >7.6 and RNA concentration >5.7 ng/l obtained from both populations. Reverse Transcriptase-PCR (RT-PCR) confirmed that the EGFP-positive cell populations express known genetic markers of cone photoreceptors that were not expressed in the EGFP-negative cell population. This work is an important step towards the identification of cone photoreceptor-enriched genes, protein and signalling networks responsible for their development, survival and function. In addition, this advancement facilitates the identification of novel candidate genes for inherited human blindness.
HDAC6 inhibition by tubastatin A is protective against oxidative stress in a photoreceptor cell line and restores visual function in a zebrafish model of inherited blindness.
Specimen part
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