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GSE8322
Mus musculus
11 Downloadable Samples
Description
We recently found that the endoplasmic reticulum (ER) stress response (ERSR) is activated in surviving cardiac myocytes in a mouse model of in vivo myocardial infarction. ATF6 is an ER stress-activated transcription factor that induces ERSR genes, some of which encode proteins that may protect against ischemic damage. However, few ERSR genes have been identified in the heart, and there have been no gene expression profiling studies of ATF6-inducible genes, in vivo. We previously generated transgenic (TG) mice that express tamoxifen-activated ATF6, ATF6-MER, in the heart; ATF6-MER conferred tamoxifen-dependent ATF6 activation and protection from ischemic damage. To understand of the mechanism of ATF6-mediated cardioprotection, gene expression profiling of ATF6-MER TG mouse hearts was performed. Activated ATF6 changed expression levels of 1,162 genes in the heart; of the 775 ATF6-inducible genes, only 23 are known ERSR genes. One of the genes not expected to be induced by ATF6 is modulatory calcinuerin-interacting protein-1 (MCIP1). MCIP1 is induced in a calcineurin/NFAT-dependent manner during myocardial hypertrophy and it can feedback inhibit cardiomyocyte growth. We found that MCIP1 expression in cultured cardiomyocytes was increased by the prototypical ER stresser, tunicamycin (TM), or by simulated ischemia. Moreover, infecting cardiomyocytes with adenovirus encoding activated ATF6 induced MCIP1 expression and inhibited myocyte growth in response to the alpha 1-adrenergic agonist, phenylephrine. These results suggest that MCIP1 can be induced in the heart by ER stresses, such as ischemia. Moreover, b integrating hypertrophy and ER stress, MCIP-modulated myocyte growth may help rejuvenate nascent ER protein folding, which could contribute to protection from ischemic damage.
Publication Title
Coordination of growth and endoplasmic reticulum stress signaling by regulator of calcineurin 1 (RCAN1), a novel ATF6-inducible gene.
Sample Metadata Fields
Sex, Age, Specimen part, Treatment
View Samples- Mus musculus
- 1 Downloadable Sample
Description
PPAR is known for its anti-inflammatory actions in macrophages. However, which macrophage populations express PPAR in vivo and how it regulates tissue homeostasis in the steady state and during inflammation is not completely understood. We show that lung and spleen macrophages constitutively expressed PPAR, while other macrophage populations did not. Recruitment of monocytes to sites of inflammation was associated with induction of PPAR as they differentiated to macrophages. Its absence in these macrophages led to failed resolution of inflammation, characterized by persistent, low-level recruitment of leukocytes. Conversely, PPAR agonists supported an earlier cessation in leukocyte recruitment during resolution of acute inflammation and likewise suppressed monocyte recruitment to chronically inflamed atherosclerotic vessels. In the steady state, PPAR deficiency in macrophages had no obvious impact in the spleen but profoundly altered cellular lipid homeostasis in lung macrophages. Reminiscent of pulmonary alveolar proteinosis, LysM-Cre x PPARflox/flox mice displayed mild leukocytic inflammation in the steady-state lung and succumbed faster to mortality upon infection with S. pneumoniae. Surprisingly, this mortality was not due to overly exuberant inflammation, but instead to impaired bacterial clearance. Thus, in addition to its anti-inflammatory role in promoting resolution of inflammation, PPAR sustains functionality in lung macrophages and thereby has a pivotal role in supporting pulmonary host defense.
Publication Title
Systemic analysis of PPARγ in mouse macrophage populations reveals marked diversity in expression with critical roles in resolution of inflammation and airway immunity.
Sample Metadata Fields
Sex, Treatment
View Samples- Mus musculus
- 10 Downloadable Samples
Description
Differential gene expression of cerebral cortex might be responsible for distinct neurovascular developments between different mouse strains
Publication Title
A novel genetic locus modulates infarct volume independently of the extent of collateral circulation.
Sample Metadata Fields
Sex, Specimen part
View Samples- Mus musculus
- 5 Downloadable Samples
Description
The retinal projection neurons, retinal ganglion cells (RGCs), can be categorized into distinct morphological and functional subtypes and by the laterality of their projections. Here, we used a new method for purifying the sparse population of ipsilaterally projecting RGCs in mouse retina from their contralaterally-projecting counterparts during embryonic development through rapid retrograde labeling followed by fluorescence-activated cell sorting (FACS). Through microarray analysis, we have uncovered the distinct molecular signatures that define and distinguish ipsilateral and contralateral RGCs during the critical period of axonal outgrowth and decussation, with over three hundred genes differentially experienced within these two cell populations. Amongst the genes upregulated in ipsilateral RGCs are many that are known to be expresed in progenitors cells and mark immaturity," including Math5 (Atoh7), Sox2, and cyclin D2. Many of these differentially regulated genes were subsequently validated via in vivo expression analysis. Thus, the molecular signatures of ipsilateral and contralateral RGCs and the mechanisms that regulate their differentiation are more diverse than previously expected.
Publication Title
Ipsilateral and Contralateral Retinal Ganglion Cells Express Distinct Genes during Decussation at the Optic Chiasm.
Sample Metadata Fields
Specimen part
View Samples- Mus musculus
- 12 Downloadable Samples
Description
BACKGROUND: p53 is an important tumor suppressor with a known role in the later stages of colorectal cancer, but its relevance to the early stages of neoplastic initiation remains somewhat unclear. Although p53-dependent regulation of Wnt signalling activity is known to occur, the importance of these regulatory mechanisms during the early stages of intestinal neoplasia has not been demonstrated.
Publication Title
A limited role for p53 in modulating the immediate phenotype of Apc loss in the intestine.
Sample Metadata Fields
Specimen part
View Samples- Mus musculus
- 8 Downloadable Samples
Description
Arx is a paired-box homeodomain transcription factor and the vertebrate ortholog to the Drosophila aristaless (al) gene. Mutations in Arx are associated with a variety of human diseases, including X-linked infantile spasm syndrome (OMIM: 308350), X-linked myoclonic epilepsy with mental retardation and spasticity (OMIM: 300432), X-linked lissencephaly with ambiguous genitalia (OMIM: 300215), X-linked mental retardation 54 (OMIM: 300419), and agenesis of the corpus callosum with abnormal genitalia (OMIM: 300004). Arx-deficient mice exhibit a complex, pleiotrophic phenotype, including decreased proliferation of neuroepithelial cells of the cortex, dysgenesis of the thalamus and olfactory bulbs, and abnormal nonradial migration of GABAergic interneurons. It has been suggested that deficits in interneuron specification, migration, or function lead to loss of inhibitory neurotransmission, which then fails to control excitatory activity and leads to epilepsy or spasticities. Given that Arx mutations are associated with developmental disorders in which epilepsy and spasticity predominate and that Arx-deficient mice exhibit deficits in interneuron migration, understanding the function of Arx in interneuron migration will prove crucial to understanding the pathology underlying interneuronopathies. Yet, downstream transcriptional targets of Arx, to date, remain unidentified.
Publication Title
Identification of Arx transcriptional targets in the developing basal forebrain.
Sample Metadata Fields
No sample metadata fields
View Samples- Mus musculus
- 8 Downloadable Samples
Description
TCPOBOP (1,4-Bis [2-(3,5-Dichloropyridyloxy)] benzene) is a constitutive androstane receptor (CAR) agonist that induces robust hepatocyte proliferation and hepatomegaly without any liver injury or tissue loss. TCPOBOP-induced direct hyperplasia has been considered to be CAR-dependent with no evidence of involvement of cytokines or growth factor signaling. Receptor tyrosine kinases (RTKs), MET and EGFR, are known to play a critical role in liver regeneration after partial hepatectomy, but their role in TCPOBOP-induced direct hyperplasia, not yet explored, is investigated in the current study. Disruption of the RTK-mediated signaling was achieved utilizing MET KO mice along with Canertinib treatment for EGFR inhibition. Combined elimination of MET and EGFR signaling [MET KO + EGFRi], but not individual disruption, dramatically reduced TCPOBOP-induced hepatomegaly and hepatocyte proliferation. TCPOBOP-driven CAR activation was not altered in [MET KO + EGFRi] mice, as measured by nuclear CAR translocation and analysis of typical CAR target genes. However, TCPOBOP induced cell cycle activation was impaired in [MET KO + EGFRi] mice due to defective induction of cyclins, which regulate cell cycle initiation and progression. TCPOBOP-driven induction of FOXM1, a key transcriptional regulator of cell cycle progression during TCPOBOP-mediated hepatocyte proliferation, was greatly attenuated in [MET KO + EGFRi] mice. Interestingly, TCPOBOP treatment caused transient decline in HNF4 expression concomitant to proliferative response; this was not seen in [MET KO + EGFRi] mice. Transcriptomic profiling revealed vast majority (~40%) of TCPOBOP-dependent genes mainly related to proliferative response, but not to drug metabolism, were differentially expressed in [MET KO + EGFRi] mice. Conclusion: Taken together, combined disruption of EGFR and MET signaling lead to dramatic impairment of TCPOBOP-induced proliferative response without altering CAR activation.
Publication Title
TCPOBOP-induced hepatomegaly & hepatocyte proliferation is attenuated by combined disruption of MET & EGFR signaling.
Sample Metadata Fields
No sample metadata fields
View Samples- Mus musculus
- 5 Downloadable Samples
Description
Homologue of Enhancer-of-split 1 (Hes1) is a transcription factor that regulates neuronal plasticity, promoting the growth of dendrites and increasing the GABAergic input. A higher expression of Hes1 also results in neuronal resistance against the noxious activity of amyloid beta, the main agent in the advent and progression of the Alzheimer's disease. As a transcription factor, Hes1 controls de expression of many genes. Using the microarray technology we have detected that the expression of one secreted synaptic protein, cerebellin 4 (Cbln4) was particularly increased upon overexpression of Hes1. We also present evidence that Cbln4 plays an essential role in the formation and maintenance of inhibitory GABAergic connections and that either overexpression of Cbln4 in cultured hippocampal neurons or the application of recombinant Cbln4 to the cultures increased the number of GABAergic varicosities and rescued neurons from amyloid beta induced cell death.
Publication Title
Cerebellin 4, a synaptic protein, enhances inhibitory activity and resistance of neurons to amyloid-β toxicity.
Sample Metadata Fields
Specimen part
View Samples- Mus musculus
- 4 Downloadable Samples
Description
This SuperSeries is composed of the SubSeries listed below.
Publication Title
Reprogramming of the microRNA transcriptome mediates resistance to rapamycin.
Sample Metadata Fields
Specimen part, Cell line
View Samples- Mus musculus
- 4 Downloadable Samples
Description
The mammalian target of rapamycin (mTOR) is a central regulator of cell proliferation. Inhibitors of mTOR are being evaluated as anti-tumor agents. Given the emerging role of microRNAs (miRNAs) in tumorgenesis we hypothesized that miRNAs could play important roles in the response of tumors to mTOR inhibitors. Rapamycin resistant myogenic cells developed by long-term rapamycin treatment showed extensive reprogramming of miRNAs expression, characterized by up-regulation of the mir-17~92 and related clusters and down-regulation of tumor-suppressor miRNAs. Antagonists of oncogenic miRNA families and mimics of tumor suppressor miRNAs (let-7) restored rapamycin sensitivity in resistant tumor cells. This study identified miRNAs as new downstream components of the mTOR-signaling pathway, which may determine the response of tumors to mTOR inhibitors.
Publication Title
Reprogramming of the microRNA transcriptome mediates resistance to rapamycin.
Sample Metadata Fields
Specimen part, Cell line
View Samples