Project description:Rationale: Estrogens attenuate cardiac hypertrophy and increase cardiac contractility via their cognate receptors ERα and ERβ. Since female sex hormones enhance global glucose utilization and because myocardial function and mass are tightly linked to cardiac glucose metabolism we tested the hypothesis that expression and activation of the estrogen receptor α (ERα) might be required and sufficient to maintain physiological cardiac glucose uptake in the murine heart. Methods and Results: Cardiac glucose uptake quantified in vivo by 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) was strongly impaired in ovarectomized compared to gonadal intact female C57BL/6JO mice. The selective ERα agonist 16α-LE2 and the non-selective ERα and ERβ agonist 17β-estradiol completely restored cardiac glucose uptake in ovarectomized mice. Cardiac FDG uptake was strongly decreased in female ERα knockout mice (ERKO) compared to wild type littermates. Biochemical assays, affymetrix cDNA array analysis, western blotting and immuno-staining of cardiac glucose transporters revealed a positive correlation of ERα dependent cardiac FDG uptake with preserved cardiac glucose transporter-1 expression and micro-vascular localization. Conclusions: Systemic activation of the ERα estrogen receptor is sufficient and its expression is required to maintain physiological glucose uptake in the murine heart, which is likely to contribute to known cardio-protective estrogen effects. total samples analysed are 20
Project description:Rationale: Estrogens attenuate cardiac hypertrophy and increase cardiac contractility via their cognate receptors ERα and ERβ. Since female sex hormones enhance global glucose utilization and because myocardial function and mass are tightly linked to cardiac glucose metabolism we tested the hypothesis that expression and activation of the estrogen receptor α (ERα) might be required and sufficient to maintain physiological cardiac glucose uptake in the murine heart. Methods and Results: Cardiac glucose uptake quantified in vivo by 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) was strongly impaired in ovarectomized compared to gonadal intact female C57BL/6JO mice. The selective ERα agonist 16α-LE2 and the non-selective ERα and ERβ agonist 17β-estradiol completely restored cardiac glucose uptake in ovarectomized mice. Cardiac FDG uptake was strongly decreased in female ERα knockout mice (ERKO) compared to wild type littermates. Biochemical assays, affymetrix cDNA array analysis, western blotting and immuno-staining of cardiac glucose transporters revealed a positive correlation of ERα dependent cardiac FDG uptake with preserved cardiac glucose transporter-1 expression and micro-vascular localization. Conclusions: Systemic activation of the ERα estrogen receptor is sufficient and its expression is required to maintain physiological glucose uptake in the murine heart, which is likely to contribute to known cardio-protective estrogen effects.
Project description:Analysis of estrogen receptor alpha function in the heart at gene expression level. The hypothesis tested in the present study was that absence of estrogen receptor alpha may induce cardiometabolic alterations. Results provide information of the responses to the absence of Estrogen receptor alpha such as core pathways that are affected, up- or down-regulated specific metabolic functions.
Project description:This SuperSeries is composed of the following subset Series: GSE22533: Breast cancer cells resistant to hormone deprivation maintain an estrogen receptor alpha-dependent, E2F-directed transcriptional program GSE27300: Estrogen-independent genomic ER binding analysis Refer to individual Series
Project description:Retinoic acid receptor-alpha (RAR alpha) is a known estrogen target gene in breast cancer cells. The consequence of RAR alpha induction by estrogen was previously unknown. We now show that RAR alpha is required for efficient estrogen receptor-alpha (ER)-mediated transcription and cell proliferation. RAR alpha can interact with ER-binding sites, but this occurs in an ER-dependent manner, providing a novel role for RAR alpha that is independent of its classic role. We show, on a genome-wide scale, that RAR alpha and ER can co-occupy regulatory regions together within the chromatin. This transcriptionally active co-occupancy and dependency occurs when exposed to the predominant breast cancer hormone, estrogen--an interaction that is promoted by the estrogen-ER induction of RAR alpha. These findings implicate RAR alpha as an essential component of the ER complex, potentially by maintaining ER-cofactor interactions, and suggest that different nuclear receptors can cooperate for effective transcriptional activity in breast cancer cells. RAR alpha silenced breast cancer MCF-7 cell lines or control siRNA in the presence of estrogen or a vehicle. MCF-7 cells were hormone-depleted for 3 d and treated with 100 nM estrogen for 12 h. There were three biological replicates for each of the four different groups.
Project description:Retinoic acid receptor-alpha (RAR alpha) is a known estrogen target gene in breast cancer cells. The consequence of RAR alpha induction by estrogen was previously unknown. We now show that RAR alpha is required for efficient estrogen receptor-alpha (ER)-mediated transcription and cell proliferation. RAR alpha can interact with ER-binding sites, but this occurs in an ER-dependent manner, providing a novel role for RAR alpha that is independent of its classic role. We show, on a genome-wide scale, that RAR alpha and ER can co-occupy regulatory regions together within the chromatin. This transcriptionally active co-occupancy and dependency occurs when exposed to the predominant breast cancer hormone, estrogen--an interaction that is promoted by the estrogen-ER induction of RAR alpha. These findings implicate RAR alpha as an essential component of the ER complex, potentially by maintaining ER-cofactor interactions, and suggest that different nuclear receptors can cooperate for effective transcriptional activity in breast cancer cells.
Project description:This experiment was conducted to identify target genes of the peroxisome proliferator-activated receptor alpha (PPARa) in skeletal muscle of transgenic mice that overexpressed PPARa. The following abstract from the published manuscript describes the major findings of this work. A potential link between muscle peroxisome proliferator- activated receptor-alpha signaling and obesity-related diabetes.Finck BN, Bernal-Mizrachi C, Han DH, Coleman T, Sambandam N, LaRiviere LL, Holloszy JO, Semenkovich CF, Kelly DP. The role of the peroxisome proliferator-activated receptor-alpha (PPARalpha) in the development of insulin-resistant diabetes was evaluated using gain- and loss-of-function approaches. Transgenic mice overexpressing PPARalpha in muscle (MCK-PPARalpha mice) developed glucose intolerance despite being protected from diet-induced obesity. Conversely, PPARalpha null mice were protected from diet-induced insulin resistance in the context of obesity. In skeletal muscle, MCK-PPARalpha mice exhibited increased fatty acid oxidation rates, diminished AMP-activated protein kinase activity, and reduced insulin-stimulated glucose uptake without alterations in the phosphorylation status of key insulin-signaling proteins. These effects on muscle glucose uptake involved transcriptional repression of the GLUT4 gene. Pharmacologic inhibition of fatty acid oxidation or mitochondrial respiratory coupling prevented the effects of PPARalpha on GLUT4 expression and glucose homeostasis. These results identify PPARalpha-driven alterations in muscle fatty acid oxidation and energetics as a potential link between obesity and the development of glucose intolerance and insulin resistance. Experiment Overall Design: RNA from two wild-type (non-transgenic (NTG)) and two PPARalpha overexpressing (MCK-PPARa) mice was analyzed. Two replicates of each are provided.