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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
- 8 Downloadable Samples
Description
Major causes of lipid accumulation in liver are increased import, synthesis or decreased catabolism of fatty acids. The latter is caused by dysfunction of cellular organelle controlling energy homeostasis, i.e. mitochondria. However, peroxisomes appear to be an important organelle in lipid metabolism of hepatocytes, but little is known about their role in the development of non-alcoholic fatty liver disease (NAFLD). To investigate the role of peroxisomes next to mitochondria in excessive hepatic lipid accumulation we used the leptin resistant db/db mice on C57BLKS background, a mouse model that develops hyperphagia induced diabetes with obesity and NAFLD.
Publication Title
Peroxisomes compensate hepatic lipid overflow in mice with fatty liver.
Sample Metadata Fields
Sex, Age, Specimen part
View Samples- Mus musculus
- 6 Downloadable Samples
Description
This SuperSeries is composed of the SubSeries listed below.
Publication Title
Gfi1b: a key player in the genesis and maintenance of acute myeloid leukemia and myelodysplastic syndrome.
Sample Metadata Fields
Specimen part
View Samples- Mus musculus
- 6 Downloadable Samples
Description
Differentiation of hematopoietic stem cells (HSCs) is regulated by a concert of different transcription factors (TFs). A disturbed function of TFs can be the basis of (pre)malignancies such as myelodysplastic syndrome (MDS) or acute myeloid leukemia (AML). Growth Factor Independence 1b (Gfi1b) is a repressing TF with a key role in quiescence of HSCs and emergence and maturation of erythrocytes and platelets. Here, we show that low expression of GFI1B in blast cells is associated with inferior prognosis of MDS and AML patients. Using mouse models with either reduced expression or conditional deletion of Gfi1b, crossed with a mouse model reflecting human MDS or AML, we demonstrate that AML development was accelerated with heterozygous loss of Gfi1b, and latency was further decreased when Gfi1b was conditionally deleted. Loss of Gfi1b significantly enhanced stemness of leukemic cells with upregulation of genes fundamentally involved in leukemia development. On a molecular level, we found that loss of Gfi1b not only increased the levels of reactive oxygen species (ROS) but also induced gene expression changes of key AML pathways such as the p38/AKT pathway. These results demonstrate that Gfi1b functions as an oncosuppressor in MDS/AML development.
Publication Title
Gfi1b: a key player in the genesis and maintenance of acute myeloid leukemia and myelodysplastic syndrome.
Sample Metadata Fields
Specimen part
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