Hormone-stimulated lipolysis in cardiac myocytes.
Ontology highlight
ABSTRACT:
SUBMITTER: Palmer WK
PROVIDER: S-EPMC1152493 | biostudies-other | 1983 Oct
REPOSITORIES: biostudies-other
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Project description:We have previously found that overexpression of CHF1/Hey2 in the myocardium prevents the development of phenylephrine-induced hypertrophy. To identify transcriptional pathways regulated by CHF1/Hey2, we cultured primary neonatal mouse cardiac myocytes from wild type and transgenic mice overexpressing CHF1/Hey2 and treated them with serum, a potent hypertrophic stimulus. We verified that overexpression of CHF1/Hey2 suppressed cardiac myocyte hypertrophy induced by serum and then determined transcriptional profiles by microarray hybridization. We identified and verified important downstream target genes by single gene analysis and qRT-PCR and then identified important biological processes by Gene Set Analysis using Biological Process Gene Sets from the Gene Ontology Consortium. We found that CHF1/Hey2 suppresses pathways involved in water transport, adenylate cyclase activity, embryonic eye morphogenesis, gut development and fluid transport after serum stimulation. Genes involved in protein dephosphorylation, demonstrate increased expression in myocytes overexpressing CHF1/Hey2, independent of serum treatment. Genes overexpressed prior to serum treatment are involved in regulation of transcription factor activity, nuclear protein export and steroid hormone receptor signaling. Genes overexpressed after serum treatment are involved in autophagy, apoptosis and mitochondrial biogenesis.
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Project description:Transgenic mice with cardiac-restricted overexpression of connective tissue growth factor (CTGF) have substantially increased tolerance towards ischemia/reperfusion injury. In the transgenic mouse model, we found that CTGF induces expression of severeal genes putatively involved in cardioprotection. The purpose of this study was to determine gene expression in cardiac myocytes stimulated with purified, recombinant CTGF, comparing unstimulated and stimulated samples. The cytoprotective actions of CTGF was recflected in the transcriptome of CTGF-stimulated cardiac myocytes. Gene ontology analysis revealed that genes included under the terms anti-apoptosis, response to wounding, and response to stress were significantly overrepresented in cardiac myocytes exposed to CTGF. Serveral of the most higly up-regulated genes have previously been reported to exert cardioprotective actions and increase tolerance towards ischemia/reperfusion injury.
2015-02-01 | GSE36073 | GEO
Project description:Transgenic mice with cardiac-restricted overexpression of connective tissue growth factor (CTGF) have substantially increased tolerance towards ischemia/reperfusion injury. In the transgenic mouse model, we found that CTGF induces expression of severeal genes putatively involved in cardioprotection. The purpose of this study was to determine gene expression in cardiac myocytes stimulated with purified, recombinant CTGF, comparing unstimulated and stimulated samples. The cytoprotective actions of CTGF was recflected in the transcriptome of CTGF-stimulated cardiac myocytes. Gene ontology analysis revealed that genes included under the terms anti-apoptosis, response to wounding, and response to stress were significantly overrepresented in cardiac myocytes exposed to CTGF. Serveral of the most higly up-regulated genes have previously been reported to exert cardioprotective actions and increase tolerance towards ischemia/reperfusion injury. Primary, adult cardiac myocytes were cultured in the absence (n=6) or presence (n=6) of 200 nmol/L recombinant CTGF for 48 hours.
2015-02-01 | E-GEOD-36073 | biostudies-arrayexpress
Project description:Isolated muscle cells from adult rat heart were used to study the relationship between myocardial insulin processing and insulin action on 3-O-methylglucose transport at 37 degrees C. Internalization of the hormone as measured by determination of the non-dissociable fraction of cell-bound insulin increased linearly up to 10 min, reaching a plateau by 30-60 min at 3 nM-insulin. At this hormone concentration the onset of insulin action was found to be biphasic, with a rapid phase up to 8 min, followed by a much slower phase, reaching maximal insulin action by 30-60 min. Insulin internalization was totally blocked by phenylarsine oxide, whereas dansylcadaverine had no effect on this process. Initial insulin action (5 min) on glucose transport was not affected by chloroquine and dansylcadaverine, but was completely abolished by treatment of cardiocytes with phenylarsine oxide. This drug effect was partly prevented by the presence of 2,3-dimercaptopropanol. Under steady-state conditions (60 min), the stimulatory action of insulin was decreased by about 60% by both chloroquine and dansylcadaverine. This study, demonstrates that insulin action on cardiac glucose transport is mediated by processing of the hormone. The data suggest dual pathways of insulin action involving initial processing of hormone-receptor complexes and lysosomal degradation.
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Project description:ADP-ribosylation factor 6 (Arf6) is a small GTPase that influences membrane receptor trafficking and the actin cytoskeleton. In adipocytes, Arf6 regulates the trafficking of the glucose transporter type 4 (GLUT4) and consequently insulin-stimulated glucose transport. Previous studies also indicated a role of Arf6 in adrenergic receptor trafficking, but whether this contributes to the control of lipolysis in adipocytes remains unknown. This was examined in the present study by using RNA interference (RNAi) and pharmaceutical inhibition in murine cultured 3T3-L1 adipocytes. Downregulation of Arf6 by RNAi impairs isoproterenol-stimulated lipolysis specifically but does not alter triacylglycerol (TAG) synthesis or the insulin signaling pathway. Neither total TAG amounts nor TAG fatty acid compositions are altered. The inhibitory effect on lipolysis is mimicked by dynasore, a specific inhibitor for dynamin, which is required for endocytosis. In contrast, lipolysis triggered by reagents that bypass events at the plasma membrane (e.g., forskolin, isobutylmethylxanthine or 8-bromo-cAMP) is not affected. Moreover, Arf6 protein levels in white adipose tissues are markedly increased in ob/ob mice, whereas they are decreased in obesity-resistant CD36 null mice. These changes reflect at least in part alterations in Arf6 mRNA levels. Collectively, these results suggest a role of the endocytic pathway and its regulation by Arf6 in adrenergic stimulation of lipolysis in adipocytes and potentially in the development of obesity.
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Project description:Background: We have previously found that overexpression of CHF1/Hey2 in the myocardium prevents the development of phenylephrine-induced hypertrophy and promotes physiological hypertrophy in an aortic banding model. To identify transcriptional pathways regulated by CHF1/Hey2 in hypertrophy, we cultured primary neonatal mouse cardiac myocytes from wild type and transgenic mice overexpressing CHF1/Hey2 and treated them with serum, a potent hypertrophic stimulus. We determined transcriptional profiles by hybridization to Affymetrix GeneChip® Mouse Gene 1.0 ST Arrays. We identified important biological processes regulated by CHF1/Hey2 by Gene Set Analysis using Biological Process Gene Sets from the Gene Ontology Consortium. Results: We found that overexpression of CHF1/Hey2 suppresses gene sets involved in water transport, regulation of adenylate cyclase activity, embryonic eye morphogenesis, gut development and fluid transport after serum stimulation. Genes involved in protein dephosphorylation, in contrast, demonstrate increased expression in myocytes overexpressing CHF1/Hey2, and this increase is independent of serum treatment. Genes overexpressed prior to serum treatment are involved in regulation of transcription factor activity, protein export from the nucleus, and steroid hormone receptor signaling. Genes overexpressed after serum treatment are involved in autophagy, apoptosis and mitochondrial biogenesis. Conclusions: CHF1/Hey2 suppresses fluid transport, activation of adenylate cyclase activity, promotes phosphatase activity, autophagy and regulates other important biological processes likely relevant to hypertrophy.
2010-01-04 | GSE14288 | GEO
Project description:Background: We have previously found that overexpression of CHF1/Hey2 in the myocardium prevents the development of phenylephrine-induced hypertrophy and promotes physiological hypertrophy in an aortic banding model. To identify transcriptional pathways regulated by CHF1/Hey2 in hypertrophy, we cultured primary neonatal mouse cardiac myocytes from wild type and transgenic mice overexpressing CHF1/Hey2 and treated them with serum, a potent hypertrophic stimulus. We determined transcriptional profiles by hybridization to Affymetrix GeneChip® Mouse Gene 1.0 ST Arrays. We identified important biological processes regulated by CHF1/Hey2 by Gene Set Analysis using Biological Process Gene Sets from the Gene Ontology Consortium. Results: We found that overexpression of CHF1/Hey2 suppresses gene sets involved in water transport, regulation of adenylate cyclase activity, embryonic eye morphogenesis, gut development and fluid transport after serum stimulation. Genes involved in protein dephosphorylation, in contrast, demonstrate increased expression in myocytes overexpressing CHF1/Hey2, and this increase is independent of serum treatment. Genes overexpressed prior to serum treatment are involved in regulation of transcription factor activity, protein export from the nucleus, and steroid hormone receptor signaling. Genes overexpressed after serum treatment are involved in autophagy, apoptosis and mitochondrial biogenesis. Conclusions: CHF1/Hey2 suppresses fluid transport, activation of adenylate cyclase activity, promotes phosphatase activity, autophagy and regulates other important biological processes likely relevant to hypertrophy. Transgenic Mice and Neonatal Mouse Myocyte Culture: WT no serum, 5; WT with serum, 7; TG no serum, 6; TG with serum, 7.
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