The molecular chaperone HSP90 aids the maturation of a diverse but select set of metastable protein clients, many of which are key to a variety of signal transduction pathways. HSP90 function has been best investigated in animal and fungal systems, where inhibition of the chaperone has exceptionally diverse effects, ranging from reversing oncogenic transformation to facilitating the acquisition of drug resistance. Inhibition of HSP90 in the model plant Arabidopsis thaliana uncovers novel morphologies dependent on normally cryptic genetic variation and increases stochastic variation inherent to developmental processes. The biochemical activity of HSP90 is strictly conserved between animals and plants. However, the substrates and pathways dependent on HSP90 in plants are poorly understood. Progress has been impeded by reliance on light-sensitive HSP90 inhibitors due to redundancy in the A. thaliana HSP90 gene family. Here we present phenotypic and genome-wide expression analyses of A. thaliana with constitutively reduced HSP90 levels achieved by RNAi targeting. HSP90 reduction affects a variety of quantitative life-history traits, including flowering time and total seed set, and decreases developmental stability. Further, by quantitative analysis of morphological phenotypes, we demonstrate that HSP90-reduction increases phenotypic diversity in both seedlings and adult plants. Several morphologies are synergistically affected by HSP90 and growth temperature. Genome-wide expression analyses also suggest a central role for HSP90 in the genesis and maintenance of plastic responses. The expression results are substantiated by examination of the response of HSP90-reduced plants to attack by caterpillars of the generalist herbivore Trichoplusia ni. HSP90 reduction potentiates a more robust herbivore defense response. In sum, we propose that HSP90 exerts global effects on the environmental responsiveness of plants to many different stimuli. The comprehensive set of HSP90-reduced lines described here is a vital instrument to further examine the role of HSP90 as a central interface between organism, development, and environment.
Phenotypic diversity and altered environmental plasticity in Arabidopsis thaliana with reduced Hsp90 levels.
Age, Specimen part
View SamplesWe have investigated the regulation of anchorage-independent growth (AIG) by basic fibroblast growth factor (bFGF) and 12-O-tetradecanoyl phorbol-13-acetate (TPA) in JB6 mouse epidermal cells in the context of wound repair versus carcinogenesis responses. bFGF induces an unusually efficient but reversible AIG response, relative to TPA-induced AIG which is irreversible. Distinct global gene expression profiles are associated with anchorage-independent colonies arising from bFGF-stimulated JB6 cells, relative to colonies arising from fully tumorigenic JB6 cells (RT101), including genes exhibiting reciprocal regulation patterns. Thus, while TPA exposure results in commitment to an irreversible and tumorigenic AIG phenotype, the AIG response to bFGF is reversible with essentially complete restoration of normal cell cycle check point control following removal of bFGF from growth medium. These results are consistent with the physiological role of bFGF in promoting wound healing, and suggest that natural mechanisms exist to reverse transformative cellular phenotypes associated with carcinogenesis.
Cellular dichotomy between anchorage-independent growth responses to bFGF and TPA reflects molecular switch in commitment to carcinogenesis.
No sample metadata fields
View SamplesUsing a macrophage cell line, we demonstrate the ability of amorphous silica particles to stimulate inflammatory protein secretion and induce cytotoxicity. Whole genome microarray analysis of early gene expression changes induced by 10nm and 500nm particles showed that the magnitude of change for the majority of genes correlated more tightly with particle surface area than either particle mass or number. Gene expression changes that were size-specific were also identified, however the overall biological processes represented by all gene expression changes were nearly identical, irrespective of particle diameter. Our results suggest that on an equivalent nominal surface area basis, common biological modes of action are expected for nano- and supranano-sized silica particles.
Macrophage responses to silica nanoparticles are highly conserved across particle sizes.
No sample metadata fields
View SamplesBisphenol-A is a widespread endocrine disruptor chemical. In utero or perinatal exposure to bisphenol-A (BPA), leads to impaired glucose metabolism during adulthood. To investigate the consequences of the exposure to bisphenol-A during development in pancreatic beta-cell growth
Maternal Exposure to Bisphenol-A During Pregnancy Increases Pancreatic β-Cell Growth During Early Life in Male Mice Offspring.
Sex, Specimen part
View SamplesPhenotypic changes induced by extracellular vesicles (EVs) have been implicated in the recovery of acute kidney injury (AKI) induced by mesenchymal stromal cells (MSCs). miRNAs are potential candidates for cell reprogramming towards a pro-regenerative phenotype. The aim of the present study was to evaluate whether miRNA de-regulation inhibits the regenerative potential of MSCs and derived-EVs in a model of glycerol-induced AKI in SCID mice. For this purpose, we generated MSCs depleted of Drosha, a critical enzyme of miRNA maturation, to alter miRNA expression within MSCs and EVs. Drosha knock-down MSCs (MSC-Dsh) maintained the phenotype and differentiation capacity. They produced EVs that did not differ from those of wild type cells in quantity, surface molecule expression and internalization within renal tubular epithelial cells. However, EVs derived from MSC-Dsh (EV-Dsh) showed global down-regulation of miRNAs. Whereas, wild type MSCs and derived EVs were able to induce morphological and functional recovery in AKI, MSC-Dsh and EV-Dsh were ineffective. RNA sequencing analysis showed that genes deregulated in the kidney of AKI mice were restored by treatment with MSCs and EVs but not by MSC-Dsh and EV-Dsh. Gene Ontology analysis showed that down-regulated genes in AKI were associated with fatty acid metabolism. The up-regulated genes in AKI were involved in inflammation, ECM-receptor interaction and cell adhesion molecules. These alterations were reverted by treatment with wild type MSCs and EVs, but not by the Drosha counterparts. In conclusion, miRNA depletion in MSCs and EVs significantly reduced their intrinsic regenerative potential in AKI, suggesting a critical role of miRNAs. Overall design: RNA-seq
AKI Recovery Induced by Mesenchymal Stromal Cell-Derived Extracellular Vesicles Carrying MicroRNAs.
No sample metadata fields
View SamplesBrown adipose tissue (BAT) thermogenesis and the browning of white adipose tissue are important components of energy expenditure. An RNAseq-based analysis of the mouse BAT transcriptome led us to identify GPR120 as a gene induced by thermogenic activation. GPR120, a G protein-coupled receptor binding unsaturated long-chain fatty acids, is known to mediate some beneficial metabolic actions of polyunsaturated fatty acids. We show that pharmacological activation of GPR120 induces BAT activity and promotes the browning of white fat in mice, whereas GRP120-null mice show impaired browning in response to cold. n-3 polyunsaturated fatty acids induce brown and beige adipocyte differentiation and thermogenic activation, and these effects require GPR120. GPR120 activation induces the release of fibroblast growth factor-21 (FGF-21) by brown and beige adipocytes and increases blood FGF21 levels. The effects of GPR120 activation are impaired in FGF21-null mice and cells. Thus, the lipid sensor GPR120 constitutes a novel pathway of brown fat activation and involves FGF21. Overall design: eight adult male C57BL6 mice were maintained at thermoneutral temperature (29C). After two weeks, a subset of four mice was placed at 4C environment temperature for 24h. RNAseq was performed on the BAT tissues of these 2 groups.
The kallikrein-kinin pathway as a mechanism for auto-control of brown adipose tissue activity.
Sex, Specimen part, Subject
View SamplesThis SuperSeries is composed of the SubSeries listed below.
DNA methylation fingerprint of neuroblastoma reveals new biological and clinical insights.
Specimen part
View SamplesDNA methylation changes in neuroblastoma, a clinically-heterogeneous pediatric tumor, have been described essentially in promoter regions. We analyzed the DNA methylome of neuroblastoma using high-density microarrays and observed differential methylation not only in promoters but also in intragenic and intergenic regions at both CpG and non-CpG sites. These epigenetic changes showed a non-random distribution relative functional chromatin domains, and targeted development and cancer-related genes, relevant for neuroblastoma pathogenesis. CCND1, a gene overexpressed in neuroblastoma, showed hypomethylation of gene-body and upstream regulatory regions. Furthermore, tumors with diverse clinical-risk showed clear differences affecting CpG and, remarkably, non-CpG sites. Non-CpG methylation was present in clinically-favorable tumors and affected genes such as ALK, where non-CpG methylation correlated with low gene expression. Finally, we identified CpG and non-CpG methylation signatures which correlated with patients age at time-points relevant for neuroblastoma clinical behavior, and targeted genes related to neural development and neural crest regulatory network
DNA methylation fingerprint of neuroblastoma reveals new biological and clinical insights.
Specimen part
View SamplesThe Drosophila insulator-binding proteins (IBPs) dCTCF/Beaf32 mark the physical borders of chromosomal domains involving co-factors that participate in long-range interactions. Chromosomal borders are further enriched in specific histone modifications yet the implication of histone modifiers and nucleosome dynamics remains largely unknown in such context. Here, we show that IBP depletion impairs nucleosome dynamics over genes flanked by their binding sites. Biochemical purification identifies a key histone methyltransferase of H3K36, NSD/dMes-4, as a novel co-factor of IBPs involved in chromatin accessibility, which specifically co-regulates hundreds of genes flanked by Beaf32/dCTCF. dMes-4 presets chromatin before the recruitment of transcriptional activators including DREF that triggers Set2/Hypb-mediated H3K36me3, RNA splicing and nucleosome positioning. Our results unveil a model for how IBPs regulate gene expression and nucleosome dynamics through NSD/dMes-4, which may contribute to regulate H3K27me3 spreading. Together, our data suggest a division of labor for how IBPs may dynamically regulate chromatin organization depending on distinct co-factors. Overall design: mRNA profiles of Beaf32-depleted or Wild-Type control Drosophila S2 cells by RNASeq (Illumina)
Insulators recruit histone methyltransferase dMes4 to regulate chromatin of flanking genes.
Cell line, Subject
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Cell-Cycle-Dependent Reconfiguration of the DNA Methylome during Terminal Differentiation of Human B Cells into Plasma Cells.
Specimen part, Subject
View Samples