Reprogramming to pluripotency after overexpression of OCT4, SOX2, KLF4 and MYC is accompanied by global genomic and epigenomic changes. Histone modification and DNA methylation states in iPSCs have been shown to be highly similar with embryonic stem cells (ESCs). However, epigenetic differences still exist between iPSCs and ESCs. In particular, aberrant DNA methylation states found in iPSCs are a major concern for using iPSCs in a clinical setting. Thus, it is critical to find factors that regulate DNA methylation states in reprogramming. Here, we found that the miR-29 family is an important epigenetic regulator during human somatic cell reprogramming. Our global DNA methylation and hydroxymethylation analysis shows that DNA demethylation is a major event mediated by miR-29a depletion during early reprogramming, and that iPSCs derived from miR-29a depletion are epigenetically closer to ESCs. Our findings uncover an important miRNA-based approach to generate clinically robust iPSCs. Overall design: Bisulphite converted gDNAs of D551 fibroblasts transduced for 3 days with overexpression of DNMTs, TETs, TDG and OSKM or miR29a/b/c and control sponge were hybridized into Illumina Infinium HumanMethylation 450K Beadchip.
Regulation of the DNA Methylation Landscape in Human Somatic Cell Reprogramming by the miR-29 Family.
Specimen part, Treatment, Subject
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Independence of repressive histone marks and chromatin compaction during senescent heterochromatic layer formation.
Sex, Cell line, Treatment
View SamplesThe expansion of repressive epigenetic marks has been implicated in heterochromatin formation during embryonic development, but the general applicability of this mechanism is unclear. Here we show that nuclear rearrangement of repressive histone marks H3K9me3 and H3K27me3 into non-overlapping structural layers characterizes senescence-associated heterochromatic foci (SAHF) formation in human fibroblasts. However, the global landscape of these repressive marks remains unchanged upon SAHF formation, suggesting that in somatic cells heterochromatin can be formed through the spatial repositioning of pre-existing repressively marked histones. This model is reinforced by the correlation of pre-senescent replication timing with both the subsequent layered structure of SAHFs and the global landscape of the repressive marks, allowing us to integrate microscopic and genomic information. Furthermore, modulation of SAHF structure does not affect the occupancy of these repressive marks nor vice versa. These experiments reveal that high-order heterochromatin formation and epigenetic remodeling of the genome can be discrete events.
Independence of repressive histone marks and chromatin compaction during senescent heterochromatic layer formation.
Sex, Cell line, Treatment
View SamplesBackground: 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 PPARα activation on whole genome gene expression in human precision cut liver slices.
Sex, Specimen part, Treatment, Subject, Time
View SamplesLittle is known about the early transcriptional events in innate immune signaling in immature and tolerogenic monocyte-derived dendritic cells (DCs), the professional antigen-presenting cells of our immune system. TLR ligands usually induce a proinflammatory transcriptional response, whereas IL10 and/or dexamethasone induce a more tolerogenic phenotype.
MicroRNA genes preferentially expressed in dendritic cells contain sites for conserved transcription factor binding motifs in their promoters.
Specimen part
View SamplesGENES ASSOCIATED WITH THE CELL CYCLE, LINEAGE COMMITMENT AND IMMUNOMODULATORY POTENTIAL DISCRIMINATE HUMAN POSTNATAL STEM CELLS OF DIFFERENT ORIGIN.
Functional differences between mesenchymal stem cell populations are reflected by their transcriptome.
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View SamplesIn this study we aimed to identify a baseline intrahepatic transcriptional signature associated with response in chronic hepatitis B patients treated with peginterferon-alfa-2a (peg-IFN) and adefovir.
An intrahepatic transcriptional signature of enhanced immune activity predicts response to peginterferon in chronic hepatitis B.
Specimen part, Disease, Disease stage
View SamplesTumor metastasis and lack of NKG2D ligand (NKG2DL) expression are associated with poor prognosis in patients with colon cancer. Here we found that spironolactone (SPIR), an FDA-approved diuretic drug with a long-term safety profile, can upregulate NKG2DL expression in multiple colon cancer cell lines by activating the ATM-Chk2-mediated checkpoint pathway, which in turn enhances tumor elimination by natural killer cells. SPIR can also upregulate the expression of metastasis-suppressor genes TIMP2 and TIMP3, thereby reducing tumor cell invasiveness. Although SPIR is an aldosterone antagonist, its anti-tumor effects are independent of the mineralocorticoid receptor pathway. Instead, by screening the human nuclear hormone receptor siRNA library, we identify retinoid X receptor gamma (RXR gamma) as being indispensable for the anti-tumor functions of SPIR. Collectively, our results strongly support the use of SPIR or other RXR gamma-agonists with minimal side effects for colon cancer prevention and therapy.
Modulation of NKG2D ligand expression and metastasis in tumors by spironolactone via RXRγ activation.
Treatment
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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
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