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GSE23497
Mus musculus
24 Downloadable Samples
Affymetrix Mouse Genome 430A 2.0 Array (mouse430a2)
Description
Skeletal muscle atrophy is a debilitating condition associated with weakness, fatigue, and reduced functional capacity. Nuclear factor-kappaB (NF-B) transcription factors play a critical role in atrophy. Knockout of genes encoding p50 or the NF-B co-transactivator, Bcl-3, abolish disuse atrophy and thus they are NF-B factors required for disuse atrophy. We do not know however, the genes targeted by NF-B that produce the atrophied phenotype. Here we identify the genes required to produce disuse atrophy using gene expression profiling in wild type compared to Nfkb1 (gene encodes p50) and Bcl-3 deficient mice. There were 185 and 240 genes upregulated in wild type mice due to unloading, that were not upregulated in Nfkb1-/- and Bcl-3-/- mice, respectively, and so these genes were considered direct or indirect targets of p50 and Bcl-3. All of the p50 gene targets were contained in the Bcl-3 gene target list. Most genes were involved with protein degradation, signaling, translation, transcription, and transport. To identify direct targets of p50 and Bcl-3 we performed chromatin immunoprecipitation of selected genes previously shown to have roles in atrophy. Trim63 (MuRF1), Fbxo32 (MAFbx), Ubc, Ctsl, Runx1, Tnfrsf12a (Tweak receptor), and Cxcl10 (IP-10) showed increased Bcl-3 binding to B sites in unloaded muscle and thus were direct targets of Bcl-3. p50 binding to the same sites on these genes either did not change or increased, supporting the idea of p50:Bcl-3 binding complexes. p65 binding to B sites showed decreased or no binding to these genes with unloading. Fbxo9, Psma6, Psmc4, Psmg4, Foxo3, Ankrd1 (CARP), and Eif4ebp1 did not show changes in p65, p50, or Bcl-3 binding to B sites, and so were considered indirect targets of p50 and Bcl-3. This work represents the first study to use a global approach to identify genes required to produce the atrophied phenotype with disuse.
Publication Title
Identification of genes that elicit disuse muscle atrophy via the transcription factors p50 and Bcl-3.
Sample Metadata Fields
Sex, Specimen part
View Samples- Mus musculus
- 8 Downloadable Samples
- Affymetrix Mouse Gene 1.0 ST Array (mogene10st)
Description
To identify atrophy genes directly targeted by Bcl-3 transactivator at a genome wide level, we performed whole transcript expression array and ChIP-seq for muscles from weight bearing or 5-day hind limb unloaded mice.
Publication Title
The ChIP-seq-defined networks of Bcl-3 gene binding support its required role in skeletal muscle atrophy.
Sample Metadata Fields
Age, Specimen part
View Samples- Mus musculus
- 12 Downloadable Samples
- Affymetrix Mouse Gene 1.0 ST Array (mogene10st)
Description
Cachexia is an exacerbating event in many types of cancer that is strongly associated with a poor prognosis. We have identified cytokine, signaling and transcription factors that are required for cachexia in the mouse C26 colon carcinoma model of cancer. C2C12 myotubes treated with conditioned medium from C26 cancer cells induced atrophy and activated a STAT-dependent reporter gene but not reporter genes dependent on SMAD, FOXO, C/EBP, NF-B, or AP-1. Of the gp130 family members IL-11, IL-6, oncostatin M (OSM), and leukemia inhibitory factor (LIF), only OSM and LIF were sufficient to activate the STAT reporter in myotubes. A LIF blocking antibody abolished C26 CM-induced STAT reporter activation STAT3 phosphorylation and myotube atrophy, but blocking antibodies to IL-6 or OSM did not. JAK2 inhibitors also blocked the C26 CM-induced STAT reporter activation, STAT3 phosphorylation, and atrophy in myotubes. LIF at levels found in the C26 CM was sufficient for STAT reporter activation and atrophy in myotubes. In vivo, an increase in serum LIF preceded the increase in IL-6 in mice with C26 tumors. Overexpression of a dominant negative Stat3C-EGFP gene in myotubes and in mouse muscle blocked the atrophy caused by C26 CM or C26 tumors, respectively. Taken together these data support an important role of LIF- JAK2-STAT3 in C26 cachexia and point to a therapeutic approach for at least some types of cancer cachexia.
Publication Title
A Key Role for Leukemia Inhibitory Factor in C26 Cancer Cachexia.
Sample Metadata Fields
Specimen part, Time
View Samples- Mus musculus
- 6 Downloadable Samples
- Affymetrix Mouse Gene 1.0 ST Array (mogene10st)
Description
Existing data suggest that NF-kappaB signaling is a key regulator of cancer-induced skeletal muscle wasting. However, identification of the components of this signaling pathway and of the NF-B transcription factors that regulate wasting is far from complete. In muscles of C26 tumor bearing mice, overexpression of d.n. IKK blocked muscle wasting by 69%, the IB-super repressor blocked wasting by 41%. In contrast, overexpression of d.n. IKK or d.n. NIK did not block C26-induced wasting. Surprisingly, overexpression of d.n. p65 or d.n. c-Rel did not significantly block muscle wasting. Genome-wide mRNA expression arrays showed upregulation of many genes previously implicated in muscle atrophy. To test if these upregulated genes were direct targets of NF-B transcription factors, we compared genome-wide p65 or p50 binding to DNA in control and cachectic muscle using ChIP-sequencing. Bioinformatic analysis of ChIP-seq data from control and C26 muscles showed increased p65 and p50 binding to a few regulatory and structural genes but only two of these genes were upregulated with atrophy. The p65 and p50 ChIP-seq data are consistent with our finding of no significant change in protein binding to an NF-B oligo in a gel shift assay. Taken together, these data support the idea that although inhibition of IB, and particularly IKK, blocks cancer-induced wasting, the alternative NF-B signaling pathway is not required. In addition, the downstream NF-B transcription factors do not regulate the transcriptional changes. These data are consistent with the growing body of literature showing that there are NF-B-independent substrates of IKK and IB that regulate physiological processes.
Publication Title
C26 cancer-induced muscle wasting is IKKβ-dependent and NF-kappaB-independent.
Sample Metadata Fields
Sex, Disease
View Samples- Rattus norvegicus
- 256 Downloadable Samples
- Affymetrix Rat Genome 230 2.0 Array (rat2302)
Description
The sexually dimorphic expression of genes across 26 somatic rat tissues was using Affymetrix RAE-230 genechips. We considered probesets to be sexually dimorphically expressed (SDE) if they were measurably expressed above background in at least one sex, there was at least a two-fold difference in expression (dimorphism) between the sexes, and the differences were statistically significant after correcting for false discovery. 14.5% of expressed probesets were SDE in at least one tissue, with higher expression nearly twice as prevalent in males compared to females. Most were SDE in a single tissue. Surprisingly, nearly half of the probesets that were (SDE) in multiple tissues were oppositely sex biased in different tissues, and most SDE probesets were also expressed without sex bias in other tissues. Two genes were widely SDE: Xist (female-only) and Eif2s3y (male-only). The frequency of SDE probesets varied widely between tissues, and was highest in the duodenum (6.2%), whilst less than 0.05% in over half of the surveyed tissues. The occurrence of SDE probesets was not strongly correlated between tissues. Within individual tissues, however, relational networks of SDE genes were identified. In the liver, networks relating to differential metabolism between the sexes were seen. The estrogen receptor was implicated in differential gene expression in the duodenum. To conclude, sexually dimorphic gene expression is common, but highly tissue-dependent. Sexually dimorphic gene expression may provide insights into mechanisms underlying phenotypic sex differences.
Publication Title
The incidence of sexually dimorphic gene expression varies greatly between tissues in the rat.
Sample Metadata Fields
Sex, Specimen part
View Samples- Rattus norvegicus
- 44 Downloadable Samples
- Affymetrix Rat Genome 230 2.0 Array (rat2302)
Description
Many heavy metals, including nickel (Ni), cadmium (Cd), and chromium (Cr) are toxic industrial chemicals with an exposure risk in both occupational and environmental settings that may cause harmful outcomes. While these substances are known to produce adverse health effects leading to disease or health problems, the detailed mechanisms remain unclear. To elucidate the processes involved in the of toxicity of nickel, cadmium, and chromium at the molecular level and to perform a comparative analysis, H4-II-E-C3 rat liver-derived cell lines were treated with soluble salts of each metal using concentrations derived from viability assays, and gene expression patterns were determined with DNA microarrays.
Publication Title
Exposure to nickel, chromium, or cadmium causes distinct changes in the gene expression patterns of a rat liver derived cell line.
Sample Metadata Fields
No sample metadata fields
View Samples- Caenorhabditis elegans
- 146 Downloadable Samples
- Affymetrix C. elegans Genome Array (celegans)
Description
The principal toxicity of acute organophosphate (OP) pesticides poisoning is the disruption of neurotransmission through inhibition of acetylcholinesterase (AChE). However, other mechanisms leading to persistent effects and neurodegeneration remain controversial and difficult to detect. Because Caenorhabditis elegans is relatively resistant to OP lethalityparticularly through the inhibition of AChEstudies in this nematode provide an opportunity to observe alterations in global gene expression following OP exposure that cannot be readily observed in less resistant organisms.
Publication Title
Alterations in gene expression in Caenorhabditis elegans associated with organophosphate pesticide intoxication and recovery.
Sample Metadata Fields
No sample metadata fields
View Samples- Drosophila melanogaster
- 5 Downloadable Samples
- Affymetrix Drosophila Genome Array (drosgenome1)
Description
The goal of this study is to identify, in the head of adult flies, mRNA species whose expresson level are altered by overexpression of the Drosophila RNA-binding protein LARK in CNS neurons.
Publication Title
The LARK RNA-binding protein selectively regulates the circadian eclosion rhythm by controlling E74 protein expression.
Sample Metadata Fields
No sample metadata fields
View Samples- Caenorhabditis elegans
- 6 Downloadable Samples
- Affymetrix C. elegans Genome Array (celegans)
Description
The Wnt signaling pathway plays a fundamental role during the development of metazoans, where it functions in the regulation of diverse processes including cell fate specification, cell migration, and stem cell renewal. Activation of the beta-catenin dependent or canonical Wnt signaling pathway upregulates expression of Wnt target genes to mediate an appropriate cellular response. In the nematode C. elegans, a Wnt signaling pathway similar to the canonical pathway regulates several processes during larval development, however few target genes of this pathway have been identified. To address this deficit, we conditionally activated Wnt signaling in living animals during a defined stage of larval life by expressing a dominant, activated beta-catenin protein, then used microarray analysis to identify genes showing altered expression compared to control animals. In this way we identified 166 differentially expressed genes, of which 104 were upregulated. A subset of the upregulated genes were validated by qPCR and showed altered expression in Wnt pathway mutants with decreased or increased Wnt signaling; we consider these genes to be candidate Wnt pathway targets in the C. elegans hermaphrodite larva. Amongst these was a group of 6 genes, including the cuticular collagen genes, bli-1 col-38, col-49 and col-71, that show a peak of expression in the mid L4 stage during normal development. The L4 expression of these genes suggests they may be expressed for use in the adult cuticle, and consistent with this, reduction of function for several of the genes leads to phenotypes suggestive of defects in cuticle function or integrity. Therefore this work has identified a large number of putative Wnt pathway target genes during larval life, including a small subset of Wnt-regulated collagen genes that may function in synthesis of the adult cuticle.
Publication Title
Use of an activated beta-catenin to identify Wnt pathway target genes in caenorhabditis elegans, including a subset of collagen genes expressed in late larval development.
Sample Metadata Fields
No sample metadata fields
View Samples- Drosophila melanogaster
- 4 Downloadable Samples
- Affymetrix Drosophila Genome Array (drosgenome1)
Description
Circadian behaviors are regulated by intrinsic biological clocks consisting of central molecular oscillators and output pathways. Despite significant progress in elucidating the central timekeeping mechanisms, the molecular pathways coupling the circadian pacemaker to overt rhythmic behavior and physiology remain elusive. The Drosophila LARK RNA-binding protein is a candidate for such a coupling factor. Previous research indicates that LARK functions downstream of the clock to mediate behavioral outputs. To better understand the roles of LARK in the Drosophila circadian system, we sought to identify RNA molecules associated with LARK in vivo, using a novel strategy that involves capturing the RNA ligands by immunoprecipitation, visualizing the captured RNAs using whole gene microarrays, and identifying functionally relevant targets through genetic screens.
Publication Title
The LARK RNA-binding protein selectively regulates the circadian eclosion rhythm by controlling E74 protein expression.
Sample Metadata Fields
No sample metadata fields
View Samples