Hormone-stimulated lipolysis in cardiac myocytes.
Ontology highlight
ABSTRACT:
SUBMITTER: Palmer WK
PROVIDER: S-EPMC1152493 | biostudies-other | 1983 Oct
REPOSITORIES: biostudies-other
Similar Datasets
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.
| S-EPMC2930668 | biostudies-literature
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.
| S-EPMC1148673 | biostudies-other
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.
| S-EPMC2853220 | biostudies-literature
Project description:Background and purposeIn cardiac myocytes, cyclic AMP (cAMP) produced by both β1 - and β2 -adrenoceptors increases L-type Ca2+ channel activity and myocyte contraction. However, only cAMP produced by β1 -adrenoceptors enhances myocyte relaxation through phospholamban-dependent regulation of the sarco/endoplasmic reticulum Ca2+ ATPase 2 (SERCA2). Here we have tested the hypothesis that stimulation of β2 -adrenoceptors produces a cAMP signal that is unable to reach SERCA2 and determine what role, if any, phosphodiesterase (PDE) activity plays in this compartmentation.Experimental approachThe cAMP responses produced by β1 -and β2 -adrenoceptor stimulation were studied in adult rat ventricular myocytes using two different fluorescence resonance energy transfer (FRET)-based biosensors, the Epac2-camps, which is expressed uniformly throughout the cytoplasm of the entire cell and the Epac2-αKAP, which is targeted to the SERCA2 signalling complex.Key resultsSelective activation of β1 - or β2 -adrenoceptors produced cAMP responses detected by Epac2-camps. However, only stimulation of β1 -adrenoceptors produced a cAMP response detected by Epac2-αKAP. Yet, stimulation of β2 -adrenoceptors was able to produce a cAMP signal detected by Epac2-αKAP in the presence of selective inhibitors of PDE2 or PDE3, but not PDE4.Conclusion and implicationsThese results support the conclusion that cAMP produced by β2 -adrenoceptor stimulation was not able to reach subcellular locations where the SERCA2 pump is located. Furthermore, this compartmentalized response is due at least in part to PDE2 and PDE3 activity. This discovery could lead to novel PDE-based therapeutic treatments aimed at correcting cardiac relaxation defects associated with certain forms of heart failure.
| S-EPMC8493936 | biostudies-literature
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:Cardiac stem cells are described in a number of mammalian species including humans. Cardiac stem cell clusters consisting of both lineage-negative and partially committed cells are generally identified between contracting cardiac myocytes. In the present study, c-kit(+), Sca(+), and Isl1(+) stem cells were revealed to be located inside the sarcoplasm of cardiac myocytes in myocardial cell cultures derived from newborn, 20-, and 40-day-old rats. Intracellularly localized cardiac stem cells had a coating or capsule with a few pores that opened into the host cell sarcoplasm. The similar structures were also identified in the suspension of freshly isolated myocardial cells (ex vivo) of 20- and 40-day-old rats. The results from this study provide direct evidence for the replicative division of encapsulated stem cells, followed by their partial cardiomyogenic differentiation. The latter is substantiated by the release of multiple transient amplifying cells following the capsule rupture. In conclusion, functional cardiac stem cells can reside not only exterior to but also within cardiomyocytes.
| S-EPMC4825596 | biostudies-literature
Project description:FAT10 is a new member of the ubiquitin-like protein family with yet-to-be defined biological functions in the heart. Our objective was to determine the role of FAT10 in the heart. FAT10 is expressed in the normal human and murine hearts, as detected by qPCR and Western blotting. Expression of FAT10 is increased in the heart at the border zone of myocardial infarction and in cultured neonatal rat cardiac myocytes (NRCM) subjected to hypoxia/reoxygenation (H/R) stress. Lentiviral-mediated overexpression of FAT10 in NRCM reduced p53 (TP53) and its target miR-34a levels, while BCL2 level, a target of miR-34a, was increased and BAX level, a pro-apoptotic protein, was reduced. These changes were associated with reduced apoptosis, detected by FACS analysis of annexin-V expression and TUNEL assay, in response to H/R injury. Knock down of FAT10 by shRNA targeting had the opposite effects. Likewise, lentiviral mediated expression of miR-34a was associated with reduced BCL2 and increased BAX levels in NRCM and also reversed changes in BCL-2 and BAX levels observed upon over-expression of FAT10. Treatment of NRCM with proteasome inhibitor MG132 increased p53 and miR-34a levels and reduced BLC2/BAX ratio. These changes were not reversed upon over-expression of FAT10. Thus, FAT10 is upregulated in the heart and NRCM in response to H/R stress, which protects cardiac myocytes against apoptosis. The anti-apoptotic effects of FAT10 are associated with suppression of p53, probably through fatylation and proteasomal degradation, reduced miR-34a expression, and a shift in the BCL2/BAX proteins against apoptosis. Thus, FAT10 is a cardioprotective protein.
| S-EPMC3646899 | biostudies-literature
Project description:Morphogenesis is often considered a function of transcriptional synchrony and the spatial limits of diffusing mitogens; however, physical constrainment by the cell microenvironment represents an additional mechanism for regulating self-assembly of subcellular structures. We asked whether myocyte shape is a distinct signal that potentiates the organization of myofibrillar arrays in cardiac muscle myocytes. We engineered the shape of neonatal rat ventricular myocytes by culturing them on microfabricated fibronectin islands, where they spread and assumed the shape of the island. Myofibrillogenesis followed, both spatially and temporally, the assembly of unique actin networks whose architecture was predictable given the shape of the island. Subsequently, the z lines of the sarcomeres aligned and registered in distinct patterns in different regions of the myocytes in such a way that orthogonal axes of contraction could be distinctly engineered. These data suggest that physical constrainment of muscle cells by extracellular matrix may be an important regulator of myofibrillar organization.
| S-EPMC3910252 | biostudies-literature