Microgravity as well as chronic muscle disuse are two causes of low back pain originated at least in part from paraspinal muscle deconditioning. At present no study investigated the complexity of the molecular changes in human or mouse paraspinal muscles exposed to microgravity. The aim of this study was to evaluate longissimus dorsi and tongue (as a new potential in-flight negative control) adaptation to microgravity at global gene expression level. C57BL/N6 male mice were flown aboard the BION-M1 biosatellite for 30 days (BF) or housed in a replicate flight habitat on ground (BG). . Global gene expression analysis identified 89 transcripts differentially regulated in longissimus dorsi of BF vs. BG mice (False Discovery Rrate < 0,05 and fold change < -2 and > +2), while only a small number of genes were found differentially regulated in tongue muscle ( BF vs. BG = 27 genes).
Microgravity-Induced Transcriptome Adaptation in Mouse Paraspinal <i>longissimus dorsi</i> Muscle Highlights Insulin Resistance-Linked Genes.
Specimen part
View SamplesMicrogravity exposure as well as chronic muscle disuse are two of the main causes of physiological adaptive skeletal muscle atrophy in humans and murine animals in physiological condition. The aim of this study was to investigate, at both morphological and global gene expression level, skeletal muscle adaptation to microgravity in mouse soleus and extensor digitorum longus (EDL). Adult male mice C57BL/N6 were flown aboard the BION-M1 biosatellite for 30 days on orbit (BF) or housed in a replicate flight habitat on Earth (BG) as reference flight control.
Gene Expression Profiling in Slow-Type Calf Soleus Muscle of 30 Days Space-Flown Mice.
Sex, Specimen part
View SamplesInflammatory breast cancer (IBC) is the most aggressive form of breast cancer. Treatment options are limited and the mechanisms underlying its aggressiveness are poorly understood. Intermittent hypoxia (IH) causes oxidative stress and is emerging as important regulator of tumor metastasis. Vessels in IBC tumors were shown to be immature, which is a primary cause of IH. We therefore investigated the relevance of IH for the modulation of gene expression in IBC cells in order to assess IH as potential regulator of IBC aggressiveness. Gene array analysis of IBC cells following chronic IH (45-60 days) demonstrated increased expression of pro-metastatic genes of the extracellular matrix, such as tenascin-C (TNC; an essential factor of the metastatic niche) and matrix metalloproteinase 9 (MMP9), and of pro-inflammatory processes, such as cyclooxygenase-2 (COX-2). Investigating the oxidative stress-dependent regulation of TNC, we found a gradual sensitivity on mRNA and protein levels. Oxidative stress activated NF-E2-related factor 2 (Nrf2), c-Jun N-terminal kinase (JNK), c-Jun and nuclear factor B (NF-B), but TNC upregulation was only dependent on NF-B activation. Pharmacological inhibition of inhibitor of NF-B (IB) phosphorylation as well as overexpression of IB prevented TNC, MMP9 and COX-2 induction, whereas the pro-inflammatory cytokine interleukin-1 (IL-1) increased their expression levels. Analysis of the gene array data showed NF-B binding sites for 64% of all upregulated genes, linking NF-B and IH-dependent regulation of pro-metastatic gene expression in IBC cells. Our results provide a first link between intermittent hypoxia and pro-metastatic gene expression in IBC cells, revealing a putative novel mechanism for the high metastatic potential of IBC.
Intermittent hypoxia confers pro-metastatic gene expression selectively through NF-κB in inflammatory breast cancer cells.
No sample metadata fields
View SamplesThe development of the central nervous system (CNS) depends on the orchestrated generation of neurons and glia from neural stem cells (NSCs). Although NSCs generate both cell types, they are produced sequentially as neurons are born first and glia later. In humans, this timing is extremely protracted and the underlying mechanisms remain unknown. Deriving glial cells such as astrocytes from human pluripotent stem cells requires 3-6 months of differentiation, greatly impeding their use in human disease modeling and regenerative medicine. Here, we report that expression of the transcription factor nuclear factor IA (NFIA) is sufficient to trigger glial competency in highly neurogenic NSCs and enables the derivation of human astrocytes within 10-12 days. NFIA-induced astrocytes are functional and shown to promote synaptogenesis, protect neurons and generate calcium transients. The mechanism of NFIA-induced glial competency involves rapid but reversible chromatin remodeling, demethylation of the GFAP promoter and a striking effect on the cell cycle. NFIA titration and pharmacological studies indicate that acquisition of a glial-compatible G1 length is critical for achieving glial competency. Our results offer mechanistic insights into human glial competency and enable the routine use of astrocytes for studying human development and disease. Overall design: The timecourse consists of 4 timpoints. Day 0 (d0) represents neurogenic LTNSCs, day 3 (d3) represents overexpression of NFIA with doxycycline and cells were harvested in bulk, day 6 (d6) represents cells sorted for CD44 while NFIA is overexpressed, day 9 (d9) represents CD44+ sorted cells replated in culture without the addition of doxycyline to downregulate NFIA and day 12 (d12) represents the same cultures in d9, but with 3 additional days of no doxycycline treatment. Each timepoint has a minimum of 3 biological replicates. Rosette cells (H9 d0) and neurons (Dapt) were profiled as controls where rosettes were one sample and neurons were performed in duplicate.
NFIA is a gliogenic switch enabling rapid derivation of functional human astrocytes from pluripotent stem cells.
No sample metadata fields
View SamplesOne clear hallmark of mammalian promoters is the presence of CpG islands (CGIs) at more than two thirds of genes whereas TATA boxes are only present at a minority of promoters. Using genome-wide approaches, we show that GC content and CGIs are major promoter elements in mammalian cells, able to govern open chromatin conformation and support paused transcription. First, we define three classes of promoters with distinct transcriptional directionality and pausing properties which correlate with their GC content. We further analyze the direct influence of GC content on nucleosome positioning and depletion, and show that CGIs correlate with nucleosome depletion both in vivo and in vitro. We also show that transcription is not essential for nucleosome exclusion but influences both a weak +1 and a well-positioned nucleosome at CGI borders. Altogether our data support the idea that CGIs have become an essential feature of promoter structure defining novel regulatory properties in mammals. Overall design: Nucleosome density and positioning were studied by high-throughput sequencing of DNA previously treated with Mnase. In parallel, chIPseq for PolII and H3K27ac were performed in mouse and human with different conditions to assess a potential effect of transcription on nucleosomes properties. To investigate transcription at promoters, we analyzed together with genome-wide Pol II accumulation by ChIP-Seq, paused bidirectional transcripts associated with transcription start sites (TSS RNAs).
CpG islands and GC content dictate nucleosome depletion in a transcription-independent manner at mammalian promoters.
Specimen part, Cell line, Subject
View SamplesThis SuperSeries is composed of the SubSeries listed below.
RNA sequencing validation of the Complexity INdex in SARComas prognostic signature.
Time
View SamplesWe validated the technological and material transfers of the CINSARC signature.
RNA sequencing validation of the Complexity INdex in SARComas prognostic signature.
Time
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Transcription-dependent generation of a specialized chromatin structure at the TCRβ locus.
Specimen part
View SamplesWe performed ChIP-Seq for hallmark TFs (Ets1, Runx1), histone modification marks (H3K4me1, H3K4me2, H3K4me3, H3K27me3, H3K36me3), total RNA Pol II, short RNA-Seq as well as nucleosome mapping mainly in murine Rag2 -/- thymocytes. We also performed ChIP-Seq for E47 as well as nucleosome mapping, gene expression microarray analysis in CD4+ CD8+ DP thymocytes. Overall, we find a key role for the transcription factor Ets1, contributing towards alpha beta T cell lineage commitment via differential transactivation of stage-specific genes orchestrated by dynamic, co-association -mediated chromatin remodeling, as well as transcription dependent generation of a specialized chromatin structure at the TCR beta locus. Overall design: Genome-wide analysis via ChIP-Seq for Ets1, Runx1, total RNA Pol II binding, H3K4me1, H3K4me2, H3K4me3, H3K27me3, H3K36me3, short RNA-Seq, Mnase-Seq in murine Rag2 -/- thymocytes, ChIP-Seq for E47, Mnase-Seq and gene expression microarray analysis in DP thymocytes This Series represents ShortRNA-Seq data.
Dynamic recruitment of Ets1 to both nucleosome-occupied and -depleted enhancer regions mediates a transcriptional program switch during early T-cell differentiation.
No sample metadata fields
View SamplesWe performed microarray analysis of gene expression in WT and Ets1-/- CD4+ CD8+ DP thymocytes. Overall, we find that Ets1-/- thymocytes display gene expression signatures closer to previous stages of thymocyte development (e.g. DN3-4) than WT DP cells, suggesting that while these cells do become DP thymocytes in the absence of Ets1, that the latter is required for the upregulation of later T-cell genes and that its presence is required for the downregulation of genes corresponding to earlier and alternative stages of development.
Dynamic recruitment of Ets1 to both nucleosome-occupied and -depleted enhancer regions mediates a transcriptional program switch during early T-cell differentiation.
Specimen part
View Samples