The aim of the study was to illucidate how BAFF mediates B cell survival and growth through the identification of BAFF-regulated genes.
BAFF controls B cell metabolic fitness through a PKC beta- and Akt-dependent mechanism.
No sample metadata fields
View SamplesAdult-onset diseases can be associated with in utero events, but mechanisms for such temporally distant dysregulation of organ function remain unknown. The polycomb histone methyltransferase, Ezh2, stabilizes transcription by depositing repressive histone marks during development that persist into adulthood, but the function of Ezh2-mediated transcriptional stability in postnatal organ homeostasis is not understood. Here, we show that Ezh2 stabilizes the postnatal cardiac gene expression program and prevents cardiac pathology, primarily by repressing the homeodomain transcription factor Six1 in differentiating cardiac progenitors. Loss of Ezh2 in embryonic cardiac progenitors, but not in differentiated cardiomyocytes, resulted in postnatal cardiac pathology, including cardiomyocyte hypertrophy and fibrosis. Loss of Ezh2 caused broad derepression of skeletal muscle genes, including the homeodomain transcription factor Six1, which is expressed in cardiac progenitors but is normally silenced upon cardiac differentiation. Many of the deregulated genes are direct Six1 targets, implying a critical requirement for stable repression of Six1 in cardiac myocytes. Indeed, upon de-repression, Six1 promotes cardiac pathology, as it was sufficient to induce cardiac hypertrophy. Furthermore, genetic reduction of Six1 levels almost completely rescued the pathology of Ezh2-deficient hearts. Thus, repression of a single transcription factor in cardiac progenitors by Ezh2 is essential for stability of the adult heart gene expression program and homeostasis. Our results suggest that epigenetic dysregulation during discrete developmental windows can predispose to adult disease and dysregulated stress responses.
Epigenetic repression of cardiac progenitor gene expression by Ezh2 is required for postnatal cardiac homeostasis.
Specimen part
View SamplesAlthough in vitro studies of embryonic stem cells have identified Polycomb repressor complexes (PRCs) as key regulators of differentiation, it remains unclear as to how PRC-mediated mechanisms control fates of multipotent progenitors in developing tissues. Here, we show that an essential PRC component, Ezh2, is expressed in epidermal progenitors, but diminishes concomitant with embryonic differentiation and with postnatal decline in proliferative activity. We show that Ezh2 controls proliferative potential of basal progenitors by repressing the Ink4A-Ink4B locus, and tempers the developmental rate of differentiation by preventing premature recruitment of AP1 transcriptional activator to the structural genes that are required for epidermal differentiation. Together, our studies reveal that PRCs control epigenetic modifications temporally and spatially in tissue-restricted stem cells by maintaining their proliferative potential and globally repressing undesirable differentiation programs, while selectively establishing a specific terminal differentiation program in a step-wise fashion.
Ezh2 orchestrates gene expression for the stepwise differentiation of tissue-specific stem cells.
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View SamplesGoal of the experiment: Analysis of gene expression changes in the cortex, striatum, hippocampus, hypothalamus, Drd2-MSNs and Drd1-MSNs of mice with a postnatal, neuron-specific ablation of GLP or G9a as compared to control mice.
Control of cognition and adaptive behavior by the GLP/G9a epigenetic suppressor complex.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Polycomb repressive complex 2 (PRC2) silences genes responsible for neurodegeneration.
Age, Specimen part
View SamplesNormal brain function critically depends on the interaction between highly specialized neurons that operate within anatomically and functionally distinct brain regions. The fidelity of neuronal specification is contingent upon the robustness of the transcriptional program that supports the neuron type-specific patterns of gene expression. Changes in neuron type-specific gene expression are commonly associated with neurodegenerative disorders including Huntingtons and Alzheimers disease. The neuronal specification is driven by gene expression programs that are established during early stages of neuronal development and remain in place in the adult brain. Here we show that the Polycomb repressive complex 2 (PRC2), which supports neuron specification during early differentiation, contributes to the suppression of the transcription program that can be detrimental for the adult neuron function. We show that PRC2 deficiency in adult striatal neurons and in cerebellar Purkinje cells impairs the maintenance of neuron-type specific gene expression. The deficiency in PRC2 has a direct impact on a selected group of genes that is dominated by self-regulating transcription factors normally suppressed in these neurons. The age-dependent progressive transcriptional changes in PRC2-deficient neurons are associated with impaired neuronal function and survival and lead to the development of fatal neurodegenerative disorders in mice.
Polycomb repressive complex 2 (PRC2) silences genes responsible for neurodegeneration.
No sample metadata fields
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Histone H3 lysine 9 di-methylation as an epigenetic signature of the interferon response.
Specimen part, Treatment
View SamplesEffective anti-viral immunity depends on the ability of infected cells or cells triggered with virus-derived nucleic acids to produce type I interferon (IFN), which activates transcription of numerous antiviral genes. However, disproportionately strong or chronic IFN expression is a common cause of inflammatory and autoimmune diseases. Here we describe an epigenetic mechanism that determines cell-type specific differences in IFN and IFN-stimulated gene expression in response to exogenous signals. We identify di-methylation of histone H3 at lysine 9 (H3K9me2) as a suppressor of IFN and IFN-inducible antiviral gene expression. We show that levels of H3K9me2 at IFN and IFN stimulated genes (ISG) correlate inversely with the scope and amplitude of IFN and ISG expression in fibroblasts and dendritic cells. Accordingly, genetic ablation or pharmacological inactivation of lysine methyltransferase G9a, which is essential for the generation of H3K9me2, resulted in phenotypic conversion of fibroblasts into highly potent IFN-producing cells and rendered these cells resistant to pathogenic RNA viruses. In summary, our studies implicate H3K9me2 and enzymes controlling its abundance as key regulators of innate antiviral immunity.
Histone H3 lysine 9 di-methylation as an epigenetic signature of the interferon response.
Treatment
View SamplesStudies investigating the causes of autism spectrum disorder (ASD) point to genetic as well as epigenetic mechanisms of the disease. Identification of epigenetic processes that contribute to ASD development and progression is of major importance and may lead to the development of novel therapeutic strategies. Here we identify the bromodomain and extra-terminal domain containing transcriptional regulators (BETs) as epigenetic drivers of an ASD-like disorder in mice. We found that the pharmacological suppression of the BET proteins by a novel, highly selective and brain-permeable inhibitor, I-BET858, leads to selective suppression of neuronal gene expression followed by the development of an autism-like syndrome in mice. Many of the I-BET858 affected genes have been linked to ASD in humans thus suggesting the key role of the BET-controlled gene network in ASD. Our studies also suggest that environmental factors controlling BET proteins or their target genes may contribute to the epigenetic mechanism of ASD.
Autism-like syndrome is induced by pharmacological suppression of BET proteins in young mice.
Specimen part
View SamplesCocaine-induced alterations in gene expression cause changes in neuronal morphology and behavior that may underlie cocaine addiction. We identified an essential role for histone 3 lysine 9 (H3K9) dimethylation and the lysine dimethyltransferase G9a in cocaine-induced structural and behavioral plasticity. Repeated cocaine administration reduced global levels of H3K9 dimethylation in the nucleus accumbens. This reduction in histone methylation was mediated through the repression of G9a in this brain region. To identify whether changes in H3K9me2 correlated with genome-wide alterations in gene expression in the NAc, we employed microarray analyses to examine gene expression profiles induced by a challenge dose of cocaine in animals with or without a history of prior cocaine exposure. Animals that had received repeated cocaine displayed dramatically increased gene expression 1 hour after a cocaine challenge in comparison to acutely treated animals. This increased gene expression still occurred in response to a cocaine challenge given after 1 week of withdrawal from repeated cocaine. These data suggest that repeated, but not acute, cocaine exposure results in persistent sensitized genomic responses to a cocaine challenge, indicating that sensitized behavioral responses to repeated cocaine are likely the result of G9a-dependent alterations in global transcriptional responses to cocaine.
Essential role of the histone methyltransferase G9a in cocaine-induced plasticity.
Specimen part
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