Project description:We have previously found that overexpression of CHF1/Hey2 in the myocardium prevents the development of phenylephrine-induced hypertrophy. To determine the role of CHF1/Hey2 in pressure overload hypertrophy, we performed ascending aortic banding on wild type and transgenic mice overexpressing CHF1/Hey2 in the myocardium. We found that both wild type and transgenic mice developed increased ventricular weight to body weight ratios one week after aortic banding. Wild type mice also developed decreased fractional shortening after one week when compared to preoperative echocardiograms and sham operated controls. Transgenic mice, in comparison, demonstrated preserved fractional shortening. Histological examination of explanted heart tissue demonstrated extensive fibrosis in wild type hearts, but minimal fibrosis in transgenic hearts. TUNEL staining demonstrated increased apoptosis in the wild type hearts but not in the transgenic hearts. Exposure of cultured neonatal myocytes from wild type and transgenic animals to hydrogen peroxide, a potent inducer of apoptosis, demonstrated increased apoptosis in the wild type cells. Gene Set Analysis of microarray data from wild type and transgenic hearts one week after banding revealed suppression and activation of multiple pathways involving apoptosis, cell signaling and biosynthesis. These findings demonstrate that CHF1/Hey2 promotes physiological over pathological hypertrophy in pressure overload through suppression of apoptosis and global regulation of multiple transcriptional pathways. Experiment Overall Design: Ascending aortic banding on four wild type and four transgenic mice were compared
Project description:We have previously found that overexpression of CHF1/Hey2 in the myocardium prevents the development of phenylephrine-induced hypertrophy. To determine the role of CHF1/Hey2 in pressure overload hypertrophy, we performed ascending aortic banding on wild type and transgenic mice overexpressing CHF1/Hey2 in the myocardium. We found that both wild type and transgenic mice developed increased ventricular weight to body weight ratios one week after aortic banding. Wild type mice also developed decreased fractional shortening after one week when compared to preoperative echocardiograms and sham operated controls. Transgenic mice, in comparison, demonstrated preserved fractional shortening. Histological examination of explanted heart tissue demonstrated extensive fibrosis in wild type hearts, but minimal fibrosis in transgenic hearts. TUNEL staining demonstrated increased apoptosis in the wild type hearts but not in the transgenic hearts. Exposure of cultured neonatal myocytes from wild type and transgenic animals to hydrogen peroxide, a potent inducer of apoptosis, demonstrated increased apoptosis in the wild type cells. Gene Set Analysis of microarray data from wild type and transgenic hearts one week after banding revealed suppression and activation of multiple pathways involving apoptosis, cell signaling and biosynthesis. These findings demonstrate that CHF1/Hey2 promotes physiological over pathological hypertrophy in pressure overload through suppression of apoptosis and global regulation of multiple transcriptional pathways.
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.
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.
Project description:Aortic banding is an excellent model system to evaluate the process of development of left ventricular hypertrophy in response to hemodynamic stress. The Affymetrix GeneChip MgU74Av1 was used to analyze expression profiles of mice at different time points after surgical intervention for pressure-overload induced hypertrophy. More information about this model may be obtained at http://cardiogenomics.med.harvard.edu/groups/proj1/pages/band_home.html Keywords = Pressure overload, cardiac hypertrophy Keywords: time-course