Skeletal muscle is a post-mitotic tissue that exhibits an extremely low turnover in the absence of disease or injury. At the same time, muscle possesses remarkable regenerative capacity mediated by satellite cells (SCs) that reside in close association with individual myofibers, underneath the fibers basal lamina. Consistent with the low turnover of the muscle, SCs in adult animals are mitotically quiescent and therefore provide an excellent model to study stem cell quiescence. As an organism grows older, the resident stem cells are exposed to a deteriorating environment and experience chronological aging. In stem cells with high turnover, the effects of chronological aging are superimposed upon the effects of the replicative aging that results from DNA replication and cell division. On the contrary, SCs experience minimal replicative aging due to their low turnover. They are thus a good model to study the consequence of chronological aging of quiescent stem cells. We performed microarray analysis of quiescent and activated SCs from both young and aged mice to understand the global gene expression profile underlying stem cell properties such as quiecence and self-renewal, and to understand how the transcriptome of a quiescent stem cell pouplation changes with age.
Chromatin modifications as determinants of muscle stem cell quiescence and chronological aging.
Treatment, Time
View SamplesA unique property of many adult stem cells is their ability to exist in a non-cycling, quiescent state. Although quiescence serves an essential role in preserving stem cell function until the stem cell is needed in tissue homeostasis or repair, defects in quiescence can lead to an impairment in tissue function, the extent to which stem cells can regulate quiescence is unknown. Here, we show that the stem cell quiescent state is composed of two distinct functional phases: G0 and an alert phase we term GAlert, and that stem cells actively and reversibly transition between these phases in response to injury-induced, systemic signals. Using genetic models specific to muscle stem cells (or satellite cells (SCs)), we show that mTORC1 activity is necessary and sufficient for the transition of SCs from G0 into GAlert and that signaling through the HGF receptor, cMet is also necessary. We also identify G0-to-GAlert transitions in several populations of quiescent stem cells. Quiescent stem cells that transition into GAlert possess enhanced tissue regenerative function. We propose that the transition of quiescent stem cells into GAlert functions as an 'alerting' mechanism, a novel adaptive response that positions stem cells to respond rapidly under conditions of injury and stress without requiring cell cycle entry or a cell fate commitment.
mTORC1 controls the adaptive transition of quiescent stem cells from G0 to G(Alert).
Specimen part, Treatment, Time
View SamplesThe study demontrates differences in the transcriptome ( both of protein coding transcripts and long non-coding RNAs) in the unilateral ureteric obstruction model of renal fibrosis. Overall design: Renal tissue was studied from animals undergoing sham operation (as controls) or right ureteric ligation. Animals were sacrificed 2 and 8 days following ligation and the right kidney tissue was examined.
Whole-transcriptome analysis of UUO mouse model of renal fibrosis reveals new molecular players in kidney diseases.
Sex, Age, Specimen part, Cell line, Subject
View SamplesInflammatory breast cancer (IBC) is an aggressive form of BC poorly defined at the molecular level. We compared the molecular portraits of 63 IBC and 134 non-IBC (nIBC) clinical samples. Genomic imbalances of 49 IBCs and 124 nIBCs were determined using high-resolution array-comparative genomic hybridization, and mRNA expression profiles of 197 samples using whole-genome microarrays. Genomic profiles of IBCs were as heterogeneous as those of nIBCs, and globally relatively close. However, IBCs showed more frequent complex patterns and a higher percentage of genes with CNAs per sample. The number of altered regions was similar in both types, although some regions were altered more frequently and/or with higher amplitude in IBCs. Many genes were similarly altered in both types; however, more genes displayed recurrent amplifications in IBCs.
High-resolution comparative genomic hybridization of inflammatory breast cancer and identification of candidate genes.
Age
View SamplesAnalysis of the response to arginine of the Escherichia coli K-12 transcriptome by microarray hybridization and real-time quantitative PCR provides a first coherent quantitative picture of the ArgR-mediated repression of arginine biosynthesis and uptake genes. Transcriptional repression was shown to be the major control mechanism of the biosynthetic genes, leaving only limited room for additional transcriptional or post-transcriptional regulations. The art genes coding for the specific arginine uptake system are subject to ArgR-mediated repression,
The arginine regulon of Escherichia coli: whole-system transcriptome analysis discovers new genes and provides an integrated view of arginine regulation.
No sample metadata fields
View SamplesScreening small molecules and drugs for activity to modulate alternative splicing, we found that amiloride, distinct from four other intracellular pH-affecting analogues, could normalize the splicing of BCL-X, HIPK3 and RON/MISTR1 transcripts in human hepatocellular carcinoma Huh-7 cells. To elucidate the underlying mechanisms, our proteomic analyses of amiloride-treated cells detected hypo-phosphorylation of splicing factor SF2/ASF and also decreased levels of SRp20 and two un-identified SR proteins. We further observed decreased phosphorylation of AKT, ERK1/2 and PP1, while increased phosphorylation of p38 and JNK, suggesting that amiloride treatment down-regulated kinases and up-regulated phosphatases in the signal pathways known to affect the splicing factor protein phosphorylation. The amiloride effects of splicing factor protein hypo-phosphorylation andnormalizedoncogenic RNA splicing were both abrogated by pre-treatment with a PP1 inhibitor. We then performed global exon array analysis of Huh-7 cells treated with amiloride for 24 hours. Using gene array chips (Affymetrix GeneChip Human Exon 1.0 ST Array of >518000 exons of 42974 genes) for exon array analysis (set parameters of correlation coefficient 0.7, splicing index -1.585 , and log2 ratio -1.585), we found that amiloride influenced the splicing patterns of 551 genes involving at least 584 exons, which included 495 known protein-coding genes involving 526 exons, many of which play key roles in functional networks of ion transport, extracellular matrix, cytoskeletons and genome maintenance. Cellular functional analyses revealed subsequent invasion and migration defects, cell cycle disruption, cytokinesis impairment, and lethal DNA degradation in amiloride-treated Huh-7 cells. This study thus provides mechanistic underpinnings for exploiting small molecule modulation of abnormal RNA splicing for cancer therapeutics.
Small molecule amiloride modulates oncogenic RNA alternative splicing to devitalize human cancer cells.
Cell line
View SamplesNotch receptors direct the differentiation of T helper (Th) cell subsets, but their influence on regulatory T (TR) cell responses is obscure. Interruption of Notch signaling in TR cells resulted in a super-regulatory phenotype, with suppression of TR cell Th1 programming and apoptosis as well as Th1 cell responses in systemic inflammation. In contrast, gain of function Notch1 signaling in TR cells resulted in lymphoproliferation, dysregulated Th1 responses and autoimmunity. To determine mechanisms by which Notch signaling may alter TR cell function, we compared the transcriptional profiles of splenic TR cells of Foxp3EGFPCre mice with those of Foxp3EGFPCreR26N1c/N1c (gain of function Notch signaling), Foxp3EGFPCreRBPJ/ (loss of function canonical Notch signaling), and Foxp3EGFPCreR26N1c/N1cRBPJ/ mice (gain of function/canonical loss of function Notch signaling).
Control of peripheral tolerance by regulatory T cell-intrinsic Notch signaling.
Sex, Age, Specimen part
View SamplesMechanisms by which regulatory T (Treg) cells fail to control inflammation in asthma remain poorly understood. We show that a severe asthma-associated polymorphism in the interleukin-4 receptor alpha chain (IL-4Ra-R576) biases induced Treg (iTreg) cells towards a T helper 17 (TH17) cell fate. This skewing reflects the recruitment by IL-4Ra-R576 of the adaptor protein growth factor receptor-bound protein 2 (GRB2), which drives IL-17 expression by an extracellular signal-regulated kinase-, IL-6- and STAT3-dependent mechanism. We showed that the IL-4Ra-R576 mutation elicits TH17 airway responses in vivo, in a house dust mite (HDM)- or ovalbumin (OVA)-driven model of airway inflammation in the mice carry the IL-4Ra-R576 mutation (Il4raR576 mice). Treg cell-specific deletion of genes encoding IL-6Ra or the master TH17 cell regulator Retinoid-related Orphan Receptor ?t (ROR?t), but not IL-4 and IL-13, protected mice against exacerbated airway inflammation induced by IL-4Ra--576. Analysis of lung tissue Treg cells revealed that the expression of IL-17 and the TH17 cell-associated chemokine receptor CCR6 was largely overlapping and highly enriched in Treg and conventional T (Tconv) cells of allergen-treated Il4raR576 mice. To further characterize the subset of IL-17 producing Foxp3+ Treg in the lung of OVA-treated mice we utilized CCR6 as a marker of Treg cells committed towards the TH17 cell lineage to examine their functional, epigenetic and transcriptional profiles. CCR6+Foxp3EGFP+ Treg cells isolated from OVA-sensitized and challenged Il4raR576 mice, by FACS (Fluorescence Activated Cell Sorting) exhibited decreased methylation of the Foxp3 CNS2 locus comparing to CCR6–Foxp3EGFP+ Treg cells from same animals, indicative of decreased stability. They also exhibited profoundly decreased suppressive function as compared to CCR6– WT and CCR6– Il4raR576 counterparts. Transcriptional profiling of CCR6+Foxp3EGFP+ Treg cells revealed increased relative expression in CCR6+ Il4raR576 Treg cells of genes associated with a TH17 cell signature, including Rorc, Ccr6, Il23r, Il17a, Il17f, Il1r1, Nr1d1, Cstl, and Ahr comparing to CCR6–Foxp3EGFP+ Treg cells from same animals. Overall design: Three CCR6+Foxp3EGFP+ Il4raR576 replicates and four CCR6–Foxp3EGFP+ Il4raR576 Treg replicates (controls) were sampled
An asthma-associated IL4R variant exacerbates airway inflammation by promoting conversion of regulatory T cells to TH17-like cells.
Sex, Specimen part, Subject
View SamplesAlternative splicing is a mechanism for increasing the protein variety of a limited number of genes. Studies have shown that aberrant regulations of the alternative splicing of apoptotic gene transcripts may contribute to the development of cancer. In this study, we isolated 4ß-Hydroxywithanolide E (4bHWE) from the traditional herb Physalis peruviana, and analyzed its biological effects in cancer cells. The results demonstrated that 4bHWE modulates the alternative splicing of apoptotic genes (e.g., HIPK3, SMAC/DIABLO, and SURVIVIN), changes the expression level of splicing factors (e.g., hnRNP C1/C2, ASF/SF2, SRp20, and SRp55), and induces histone tail posttranslational modifications (e.g., H3K27me1, H3K27me2, H3K36me3, and H3K79me1). Pretreatment with okadaic acid to inhibit protein phosphatase-1 could partly relieve the effects of 4bHWE on the alternative splicing of HIPK3 and SMAC/DIABLO transcripts, as well as on the dephosphorylation of ASF/SF2. Genome-wide detection of alternative splicing further indicated that several other apoptosis-related genes are also regulated by 4bHWE, including APAF1, CARP-1, and RIPK1. Moreover, we extended our study to apoptosis-associated molecules, detecting an increasing level of CASPASE-3 activity and cleavage of poly ADP-ribose polymerase in 4bHWE-induced apoptosis. Furthermore, in vivo experiments showed that the treatment of tumor-bearing mice with 4bHWE resulted in a marked decrease of tumor size and weight. Taken together, this study is the first to show that 4bHWE affects alternative splicing through the modulations of splicing factors, providing a novel view of the antitumor mechanism of 4bHWE. Overall design: Examination of the global genes with altered alternative splicing in 4bHWE-treated Huh-7 cells.
4β-Hydroxywithanolide E Modulates Alternative Splicing of Apoptotic Genes in Human Hepatocellular Carcinoma Huh-7 Cells.
Specimen part, Treatment, Subject
View SamplesWe used microarrays to detail the global transcriptional response mediated by ERalpha or ERbeta to the phytoestrogen genistein in the MCF-7 human breast cancer cell model.
Estrogen Receptors alpha and beta as determinants of gene expression: influence of ligand, dose, and chromatin binding.
No sample metadata fields
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