The combination of defined factors with small molecules targeting epigenetic factors is a strategy that has been shown to enhance optimal derivation of human iPSCs and could be used for therapeutic and regenerative medicine applications. In this study, we showed that a new first-in-class dual G9a/DNMT inhibitor CM272 compound improves the standard four-factor reprogramming efficiency of human fibroblast. The use of CM272 facilitates the generation of iPSC with only two factors, OCT4 and SOX2, allowing the removal of potentially oncogenic factors such as cMYC or KLF4. Taking a closer look at the early events occurring during cell reprogramming we demonstrated that treatment with our G9a/DNMT dual inhibitor induces heterochromatin relaxation, facilitates the engagement of OCT4 and SOX2 transcription factors to the genome and promotes mesenchymal to epithelial transition during cell reprogramming. Thus, the use of this new G9a/DNMT dual inhibitor compound may represent an interesting alternative for improving cell reprogramming.
Reversible dual inhibitor against G9a and DNMT1 improves human iPSC derivation enhancing MET and facilitating transcription factor engagement to the genome.
Sex, Specimen part, Disease, Cell line
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Foxp3 exploits a pre-existent enhancer landscape for regulatory T cell lineage specification.
Specimen part
View SamplesRegulatory T (Treg) cells, whose identity and function are defined by the transcription factor Foxp3, are indispensable for immune homeostasis. It is unclear whether Foxp3 exerts its Treg lineage specification function through active modification of the chromatin landscape and establishment of new enhancers or by exploiting a pre-existing enhancer landscape. Analysis of the chromatin accessibility of Foxp3-bound enhancers in Treg and Foxp3-negative T cells showed that Foxp3 was bound overwhelmingly to pre-accessible enhancers occupied by its cofactors in precursor cells or a structurally related predecessor. Furthermore, the bulk of Foxp3-bound Treg cell enhancers inaccessible in Foxp3- CD4+ cells became accessible upon T cell receptor activation prior to Foxp3 expression with only a small subset associated with several functionally important genes being exclusively Treg cell-specific. Thus, in a late cellular differentiation process Foxp3 defines Treg cell functionality in an opportunistic manner by largely exploiting the preformed enhancer network instead of establishing a new enhancer landscape.
Foxp3 exploits a pre-existent enhancer landscape for regulatory T cell lineage specification.
Specimen part
View SamplesDuring late gestation, structures called villi extend into the intestinal lumen to dramatically increase the surface area of the intestinal epithelium, preparing the gut for the neonatal diet. Incomplete development of the intestine is the most common gastrointestinal complication in neonates, but the causes are unclear. We provide evidence that Yin-Yang1 (Yy1) is critical for intestinal villus development. YY1 loss in the developing endoderm had no apparent consequences until late gestation, after which the intestine differentiated poorly and exhibited severely stunted villi. Transcriptome analysis revealed that YY1 is required for mitochondrial gene expression, and ultrastructural analysis confirmed compromised mitochondrial integrity in the mutant intestine. We found increased oxidative phosphorylation gene expression at the onset of villus elongation, suggesting that aerobic respiration may function as a regulator of villus growth. Mitochondrial inhibitors blocked villus growth in a fashion similar to Yy1 loss, thus further linking oxidative phosphorylation with late-gestation intestinal development. Interestingly, we find necrotizing enterocolitis patients also exhibit decreased expression of oxidative phosphorylation genes. Our study highlights the still unappreciated role of metabolic regulation during organogenesis, and suggests it may contribute to neonatal gastrointestinal disorders.
A YY1-dependent increase in aerobic metabolism is indispensable for intestinal organogenesis.
Specimen part
View SamplesPre-mRNA splicing is functionally coupled to transcription, and genotoxic stresses can enhance alternative exon inclusion by affecting elongating RNA polymerase II. We report here that various genotoxic stress inducers, including camptothecin, inhibit the interaction between EWS, an RNA polymerase II-associated factor, and YB-1, a spliceosome-associated factor. This results in the cotranscriptional skipping of several exons of the MDM2 gene encoding the main p53 ubiquitin-ligase. This reversible exon skipping participates in the timely regulation of MDM2 expression, and may contribute to the accumulation of p53 during stress exposure and its rapid shut off when stress is removed. Finally, a splicing-sensitive microarray identified numerous exons that are skipped in response to camptothecin and EWS/YB-1 depletion. These data demonstrate genotoxic stress-induced alteration of the communication between the transcriptional and splicing machineries, resulting in widespread exon skipping and playing a central role in the genotoxic stress response.
Cotranscriptional exon skipping in the genotoxic stress response.
Specimen part, Cell line
View SamplesTumor heterogeneity of high-grade glioma (HGG) is recognized by four clinically relevant subtypes based on core gene signatures. However, molecular signaling in glioma stem cells (GSCs) in individual HGG subtypes is poorly characterized. Here we identified and characterized two mutually exclusive GSC subtypes with distinct dysregulated signaling pathways. Analysis of mRNA profiles distinguished proneural (PN) from mesenchymal (Mes) GSCs and revealed a pronounced correlation with the corresponding PN or Mes HGGs. Mes GSCs displayed more aggressive phenotypes in vitro and as intracranial xenografts in mice. Further, Mes GSCs were markedly resistant to radiation compared with PN GSCs. The glycolytic pathway, comprising aldehyde dehydrogenase (ALDH) family genes and in particular ALDH1A3, were enriched in Mes GSCs. Glycolytic activity and ALDH activity were significantly elevated in Mes GSCs but not in PN GSCs. Expression of ALDH1A3 was also increased in clinical HGG compared with low-grade glioma or normal brain tissue. Moreover, inhibition of ALDH1A3 attenuated the growth of Mes but not PN GSCs. Last, radiation treatment of PN GSCs up-regulated Mes-associated markers and downregulated PN-associated markers, whereas inhibition of ALDH1A3 attenuated an irradiation-induced gain of Mes identity in PN GSCs. Taken together, our data suggest that two subtypes of GSCs, harboring distinct metabolic signaling pathways, represent intertumoral glioma heterogeneity and highlight previously unidentified roles of ALDH1A3-associated signaling that promotes aberrant proliferation of Mes HGGs and GSCs. Inhibition of ALDH1A3- mediated pathways therefore might provide a promising therapeutic approach for a subset of HGGs with the Mes signature.
Mesenchymal glioma stem cells are maintained by activated glycolytic metabolism involving aldehyde dehydrogenase 1A3.
Specimen part
View SamplesPharmacological inhibition of chromatin co-regulatory factors represents a clinically validated strategy to modulate oncogenic signaling through selective attenuation of gene expression. Here, we demonstrate that CBP/EP300 bromodomain inhibition preferentially abrogates the viability of multiple myeloma cell lines. Phenotypic effects are preceded by the direct transcriptional suppression of the lymphocyte-specific transcription factor IRF4 and the subsequent down-regulation of the IRF4 transcriptional program. Ectopic expression of IRF4 antagonizes the phenotypic effects of CBP/EP300 bromodomain inhibition and prevents the suppression of the IRF4 target c-MYC. These findings suggest that CBP/EP300 bromodomain inhibition represents a viable therapeutic strategy for targeting multiple myeloma and other lymphoid malignancies dependent on the IRF4 network. Overall design: Through the use of CBP/EP300 bromodomain inhibitors (CBP/EP300i), we demonstrate that MYC expression in BETi-resistant cells is dependent on CBP/EP300 bromodomains and that treatment with CBP/EP300i restores phenotypic sensitivity.
Bromodomain inhibition of the transcriptional coactivators CBP/EP300 as a therapeutic strategy to target the IRF4 network in multiple myeloma.
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Discovery of first-in-class reversible dual small molecule inhibitors against G9a and DNMTs in hematological malignancies.
Cell line, Treatment
View SamplesThe indisputable role of epigenetics in cancer and the fact that epigenetic alterations can be reversed have favored development of epigenetic drugs. In this study, we have design and synthesize potent novel, selective and reversible chemical probes that simultaneously inhibit the G9a and DNMTs methyltransferase activity. In vitro treatment of hematological neoplasia (Acute Myeloid Leukemia-AML, Acute Lymphoblastic Leukemia-ALL and Diffuse Large B-cell Lymphoma-DLBCL) with the lead compound CM-272, inhibited cell proliferation and promoted apoptosis, inducing interferon stimulated genes and immunogenic cell death. CM-272 significantly prolonged survival of AML, ALL and DLBCL xenogeneic models. Our results represent the discovery of first-in-class dual inhibitors of G9a/DNMTs and establish this chemical series, as a promising therapeutic tool for unmet needs in hematological tumors.
Discovery of first-in-class reversible dual small molecule inhibitors against G9a and DNMTs in hematological malignancies.
Cell line, Treatment
View SamplesWe used microarrays to assess gene expression differences in the hippocampus between FoxO6 mutant and wild-type siblings before (basal) or after novel object learning.
FoxO6 regulates memory consolidation and synaptic function.
Sex, Time
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