Mesenchymal progenitor cells can be differentiated in vitro into myotubes that exhibit many characteristic features of primary mammalian skeletal muscle fibers. However, in general, they do not show the functional excitation-contraction coupling or the striated sarcomere arrangement typical of mature myofibers. Epigenetic modifications have been shown to play a key role in regulating the progressional changes in transcription necessary for muscle differentiation. In this study, we demonstrate that treatment of murine C2C12 mesenchymal progenitor cells with 10 M of the DNA methylation inhibitor 5-azacytidine (5AC) promotes myogenesis, resulting in myotubes with enhanced maturity as compared to untreated myotubes. Specifically, 5AC treatment resulted in the upregulation of muscle genes at the myoblast stage while at later stages nearly 50 % of the 5AC-treated myotubes displayed a mature, well-defined sarcomere organization as well as spontaneous contractions that coincided with action potentials and intracellular calcium transients. Both the percentage of striated myotubes and their contractile activity could be inhibited by 20 nM TTX, 10 M ryanodine and 100 M nifedipine, suggesting that action potential-induced calcium transients are responsible for these characteristics. Our data suggest that genomic demethylation induced by 5AC overcomes an epigenetic barrier that prevents untreated C2C12 myotubes from reaching full maturity.
Epigenetics: DNA demethylation promotes skeletal myotube maturation.
Cell line, Treatment
View SamplesThe innate immune system is vital to rapidly responding to pathogens and Toll-like receptors (TLRs) are a critical component of this response. Nanovesicular exosomes play a role in immunity, but to date their exact contribution to the dissemination of the TLR response is unknown. To understand the effect of exosomal cargo released from locally stimulated cells on distal cell expression, we collected exosomes from local ovarian adenocarcinoma (HEY) cells that were either unstimulated (control-exosomes), stimulated with pIC (pIC-exosomes), or lipopolysaccharide (LPS-exosomes) for 48 hours. The three groups of exosomes were added to nave (distal) cells and the gene expression profiles were compared between local TLR stimulation (for 6 hours) and distal stimulation mediated by exosomes at the 48-hour time point
TLR-exosomes exhibit distinct kinetics and effector function.
Specimen part, Cell line, Treatment
View SamplesPlants are sessile organisms and therefore must sense and respond to changes of their surrounding conditions such as ambient temperature, which vary diurnally and seasonally. It is not yet clear how plants sense temperature and integrate this information into their development. We have previously shown that H2A.Z-nucleosomes are evicted in response to warmer temperatures. It is not clear however, whether the link between transcriptional responsiveness and changes in H2A.Z binding in context of temperature shifts is a global trend that can be seen throughout the genome, or the phenomenon is specific to a specialised set of temperature-responsive genes. In addition to the role of H2A.Z-nucleosome dynamics in the transcriptional response to temperature, it was shown that genes strongly misregulated in the h2a.z mutant are enriched for gene categories involved in response to multiple environmental cues. This suggests that H2A.Z could be implicated in the transcriptional response to various environmental inputs, raising the question: What brings the specificity of H2A.Z dynamics in response to temperature? To address this question we have profiled H2A.Z-nucleosome occupancy genome wide (using ChIP-seq) during a time course after temperature variation and compared its dynamics to transcriptional changes. We identified a fast, targeted and transient eviction of H2A.Z associated with transcriptional activation in response to temperature for a few hundreds genes. This eviction is associated with a reduction of the stability of the nucleosome. Moreover the genes with a fast H2A.Z eviction were strongly enriched in heat shock elements in their promoter and we observed a strong association between HSF1 binding and H2AZ eviction at warm temperature. These results highlight the importance of the interplay between transcription factors and chromatin to allow a controlled and dynamics response to temperature. Overall design: RNA-seq were generated in duplicate for seedlings shifted to warm temperature
Transcriptional Regulation of the Ambient Temperature Response by H2A.Z Nucleosomes and HSF1 Transcription Factors in Arabidopsis.
Subject
View SamplesPlants are sessile organisms and therefore must sense and respond to changes of their surrounding conditions such as ambient temperature, which vary diurnally and seasonally. It is not yet clear how plants sense temperature and integrate this information into their development. We have previously shown that H2A.Z-nucleosomes are evicted in response to warmer temperatures. It is not clear however, whether the link between transcriptional responsiveness and changes in H2A.Z binding in context of temperature shifts is a global trend that can be seen throughout the genome, or the phenomenon is specific to a specialised set of temperature-responsive genes. In addition to the role of H2A.Z-nucleosome dynamics in the transcriptional response to temperature, it was shown that genes strongly misregulated in the h2a.z mutant are enriched for gene categories involved in response to multiple environmental cues. This suggests that H2A.Z could be implicated in the transcriptional response to various environmental inputs, raising the question: What brings the specificity of H2A.Z dynamics in response to temperature? To address this question we have profiled H2A.Z-nucleosome occupancy genome wide (using ChIP-seq) during a time course after temperature variation and compared its dynamics to transcriptional changes. We identified a fast, targeted and transient eviction of H2A.Z associated with transcriptional activation in response to temperature for a few hundreds genes. This eviction is associated with a reduction of the stability of the nucleosome. Moreover the genes with a fast H2A.Z eviction were strongly enriched in heat shock elements in their promoter and we observed a strong association between HSF1 binding and H2AZ eviction at warm temperature. These results highlight the importance of the interplay between transcription factors and chromatin to allow a controlled and dynamics response to temperature. Overall design: RNA-seq were generated in duplicate for seedlings shifted to warm temperature
Transcriptional Regulation of the Ambient Temperature Response by H2A.Z Nucleosomes and HSF1 Transcription Factors in Arabidopsis.
Subject
View SamplesAims/hypothesis: Duct cells isolated from adult human pancreas can be reprogrammed to express islet beta cell genes by adenoviral transduction of the developmental transcription factor neurogenin3 (Ngn3). In this study we aimed to fully characterize the extent of this reprogramming and intended to improve it.
Plasticity of adult human pancreatic duct cells by neurogenin3-mediated reprogramming.
Specimen part
View SamplesMesenchymal stromal cells (MSCs) are multipotent stem cells with potent immunosuppressive and trophic support functions. Although bone marrow is considered the golden standard to isolate classical MSCs (BM-MSC), MSC-like cells are currently also derived from other, more easily accessible extra-embryonic tissues such as the umbilical cord. In this study we compared the gene expression profile of human Wharton's jelly explant-derived MSC cultures with two adult MSC populations derived from bone marrow, namely BM-MSC and multipotent adult progenitor cells (MAPC).
Human Wharton's Jelly-Derived Stem Cells Display a Distinct Immunomodulatory and Proregenerative Transcriptional Signature Compared to Bone Marrow-Derived Stem Cells.
Specimen part
View SamplesOligodendrocyte precursor cells (OPCs) constitute the main proliferative cells in the adult brain, and deregulation of OPC proliferation-differentiation balance results in either glioma formation or defective adaptive (re)myelination. OPC differentiation requires significant genetic reprogramming implicating chromatin remodeling. Mounting evidence indicates that chromatin remodelers play important roles during normal development and their mutations are associated with neurodevelopmental defects, with CHD7 haploinsuficiency being the cause of CHARGE syndrome and CHD8 being one of the strongest Autism Spectrum Disorder (ASD) high-risk associated genes. Here, we report on uncharacterized functions of the chromatin remodelers Chd7 and Chd8 in OPCs. Their OPC-chromatin-binding profile combined with transcriptome and chromatin accessibility analyses of Chd7-deleted OPCs, demonstrates that Chd7 protects non-proliferative OPCs from apoptosis by chromatin-closing and transcriptional repression of p53. Furthermore, Chd7 controls OPC differentiation through chromatin-opening and transcriptional activation of key regulators, including Sox10, Nkx2.2 and Gpr17. Chd7 is however dispensable for oligodendrocyte stage progression, consistent with Chd8 compensatory function, as suggested by their common chromatin binding profiles and genetic interaction. Finally, CHD7 and CHD8 bind in OPCs to a majority of ASD-risk associated genes, suggesting an implication of oligodendrocyte lineage cells in ASD neurological defects. Our results thus offer new avenues to understand and modulate the CHD7 and CHD8 functions in normal development and disease. Overall design: RNA-seq from Chd7iKO and Control O4+ soted cells
Oligodendrocyte precursor survival and differentiation requires chromatin remodeling by Chd7 and Chd8.
Specimen part, Subject
View SamplesThe goal was to screen for the expressed genes in Semi-Circular Canal Duct (SCCD) that are related to ion transport and its regulation. The objectives was to discover which genes changed expression levels in response to glucocorticoids.
Ion transport regulation by P2Y receptors, protein kinase C and phosphatidylinositol 3-kinase within the semicircular canal duct epithelium.
Specimen part
View SamplesThe goal was to screen for the expressed genes in Reissner's membrane (RM) that are related to ion transport and its regulation. The objectives were 1) to determine whether short-term incubation altered the transcriptome and 2 ) to discover which genes changed expression levels in response to glucocorticoids.
Regulation of ENaC-mediated sodium transport by glucocorticoids in Reissner's membrane epithelium.
Specimen part
View SamplesNon-steroidal anti-inflammatory drugs (NSAIDs) are used extensively as therapeutic agents, despite their well-documented gastrointestinal (GI) toxicity. Presently, the mechanisms responsible for NSAID-associated GI damage are incompletely understood. In this study, we used Microarray analysis to generate a novel hypothesis about cellular mechanisms that underlie the GI toxicity of NSAIDs. Monolayers of intestinal epithelial
Drug-induced alterations to gene and protein expression in intestinal epithelial cell 6 cells suggest a role for calpains in the gastrointestinal toxicity of nonsteroidal anti-inflammatory agents.
Specimen part
View Samples