The adipose tissue is an endocrine regulator and a risk factor for atherosclerosis and cardiovascular disease when by excessive accumulation induces obesity. Although the adipose tissue is also a reservoir for stem cells (ASC) their function and stemcellness has been questioned. Our aim was to investigate the mechanisms by which obesity affects subcutaneous white adipose tissue (WAT) stem cells.
Stem cells isolated from adipose tissue of obese patients show changes in their transcriptomic profile that indicate loss in stemcellness and increased commitment to an adipocyte-like phenotype.
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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.
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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 SamplesAffymetrix expression profiling was used to evaluate the association between IL13R2 expression, and mesenchymal, proneural, classical and neural signature genes expression for glioma subclasses defined by Verhaak et al (Cancer Cell; 2010).
Glioma IL13Rα2 is associated with mesenchymal signature gene expression and poor patient prognosis.
Cell line, Treatment
View SamplesMicroglia (MG) and macrophages (MPs) represent a significant component of the inflammatory response to gliomas. When activated, MG/MP release a variety of pro-inflammatory cytokines, however, they also secrete anti-inflammatory factors that limit their cytotoxic function. The balance between pro and anti-inflammatory functions dictates their antitumor activity. To evaluate potential variations in MG and MP function in gliomas, we isolated these cells (and other Gr1+ cells) from intracranial GL261 murine gliomas by FACS and evaluated their gene expression profiles by microarray analysis. As expected, arginase 1 (Arg1, M2 marker) was highly expressed by tumor-associated Gr1+, MG and MP. However, in contrast to MP and Gr1+ cells that expressed Arg1 shortly after tumor trafficking, Arg1 expression in MG was delayed and occurred in larger tumors. Interestingly, depletion of MPs in tumors did not prevent MG polarization, suggesting direct influence of tumor-specific factors on MG Arg1 upregulation. Finally, Arg1 expression was confirmed in human GBM samples, but most Arg1+ cells were neutrophils and not MPs. These findings confirm variations in tumor MG and MP polarization states and its dependency on tumor microenvironmental factors.
Characterization of Arginase Expression in Glioma-Associated Microglia and Macrophages.
Specimen part, Disease, Disease stage
View SamplesWe studied the synaptic activity-regulated gene expression response in the human genetic background using cultured human iPSC-derived (hiPSCd) neuronal networks and networks of hiPSCd neurons mixed with mouse primary neurons. Our results confirm that genetic changes affect the synaptic activity-regulated gene program, proposing a functional mechanism how they have driven evolution of human cognitive abilities. Overall design: We compared RNA profiles of untreated hiPSCd neurons and hiPSCd neurons treated with bicuculline and 4-aminopyridine for 1 or 4 hours. Samples were collected from hiPSCd neuron-only cultures and from co-cultures of hiPSCd neurons and mouse primary hippocampal neurons.
Networks of Cultured iPSC-Derived Neurons Reveal the Human Synaptic Activity-Regulated Adaptive Gene Program.
Specimen part, Subject
View SamplesUltra low input sequencing of FACS sorted primary murine microglia from CSF-1 or IL-34 deficient forebrain and cerebella, at P8 and 9 weeks Overall design: Csf1fl/fl vs NesCreCsf1fl/fl: 3-4 biological replicates per timepoint per group; Il34wt/wt vs Il34Lacz/Lacz: 2-3 biological replicates per timepoint per group. P8, 9weeks
CSF-1 controls cerebellar microglia and is required for motor function and social interaction.
Age, Specimen part, Subject
View SamplesSynaptic activity drives changes in gene expression to promote long-lasting adaptations of neuronal structure and function. One example of such an adaptive response is the buildup of acquired neuroprotection, a synaptic activity- and gene transcription-mediated increase in the resistance of neurons against harmful conditions. A hallmark of acquired neuroprotection is the stabilization of mitochondrial structure and function. We therefore re-examined previously identified sets of synaptic activity-regulated genes to identify genes that are directly linked to mitochondrial function. In mouse and rat primary hippocampal cultures synaptic activity caused an upregulation of glycolytic genes and a concomitant downregulation of genes required for oxidative phosphorylation, mitochondrial biogenesis and maintenance. Changes in metabolic gene expression were induced by action potential bursting, but not by glutamate bath application activating extrasynaptic NMDA receptors. The specific pattern of gene expression changes suggested that synaptic activity promotes a shift of neuronal energy metabolism from oxidative phosphorylation toward aerobic glycolysis, also known as Warburg effect. The ability of neurons to upregulate glycolysis has, however, been debated. We therefore used FACS sorting to show that, in mixed neuron glia co-cultures, activity-dependent regulation of metabolic gene expression occurred in neurons. Changes in gene expression were accompanied by changes in the phosphorylation-dependent regulation of the key metabolic enzyme, pyruvate dehydrogenase. Finally, increased synaptic activity caused an increase in the ratio of L-lactate production to oxygen consumption in primary hippocampal cultures. Based on these data we suggest the existence of a synaptic activity-mediated neuronal Warburg effect that may promote mitochondrial homeostasis and neuroprotection. Overall design: We compared the mRNA expression profile of primary hippocampal neurons after 4h of basal synaptic activity vs. 4h of action potential bursting. Two independent experiments with independent cell preparations were performed.
Synaptic Activity Drives a Genomic Program That Promotes a Neuronal Warburg Effect.
Specimen part, Cell line, Subject
View SamplesThe formation of long-term memory requires signaling from the synapse to the nucleus to mediate neuronal activity-dependent gene transcription. Synapse-to-nucleus communication is initiated by influx of calcium ions through synaptic NMDA receptors and/or L-type voltage-gated calcium channels and involves the activation of transcription factors by calcium/calmodulin signaling in the nucleus. Recent studies have drawn attention to a new family of transcriptional regulators, the so-called calmodulin-binding transcription activator (CAMTA) proteins. CAMTAs are expressed at particularly high levels in the mouse and human brain, and we reasoned that, as calmodulin-binding transcription factors, CAMTAs may regulate the formation of long-term memory by coupling synaptic activity and calcium/calmodulin signaling to memory-related transcriptional responses. This hypothesis is supported by genetic studies that reported a correlation between CAMTA gene polymorphisms or mutations and cognitive capability in humans. Here, we show that acute knock-down of CAMTA1, but not CAMTA2, in the hippocampus of adult mice results in impaired performance in two memory tests, contextual fear conditioning and object-place recognition test. Short-term memory and neuronal morphology were not affected by CAMTA knock-down. Gene expression profiling in the hippocampus of control and CAMTA knock-down mice revealed a number of putative CAMTA1 target genes related to synaptic transmission and neuronal excitability. Patch clamp recordings in organotypic hippocampal slice cultures provided further evidence for CAMTA1-dependent changes in electrophysiological properties. In summary, our study provides experimental evidence that confirms previous human genetic studies and establishes CAMTA1 as a regulator of long-term memory formation. Overall design: We compared the mRNA expression profile of three groups, i.e. mice infected with a recombinant adeno-associated virus (rAAV) expressing a non-targeting control shRNA, mice infected with a rAAV expressing Camta1 targeting shRNA sequence A, and mice infected with a rAAV expressing Camta1 targeting shRNA sequence B. Three animals were used per group.
The calmodulin-binding transcription activator CAMTA1 is required for long-term memory formation in mice.
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