Project description:The expression of the small molecular weight heat shock protein (Hsp) H11 kinase/Hsp22 (Hsp22) is restricted to a limited number of tissues, including the heart and skeletal muscle, both in rodents and in humans. We generated a mouse knockout (KO) model, and investigated the role of Hsp22 in regulating cardiac hypertrophy in response to pressure overload. We compared gene expression profiles between WT and KO mice in basal condition and three days pressure overload after transverse aortic constriction (TAC). These data illustrated a novel mechanism of Hsp22-related gene expression in response to cardiac stress. We used microarray to examine differential gene expression by Hsp22 deletion at baseline and 3-day pressure overload. Left ventricles from wild type and Hsp22 knockout mice were selected from basal condition (each, n=3) and TAC surgery (each, n=4).
Project description:Backgound: Cardiac pressure overload, for example in patients with aortic stenosis, induces irreversible damage in the myocardium leading to cardiac dysfunction, cardiomyocyte hypertrophy and interstitial fibrosis. We therefore hypothesized that insufficient cardiac regeneration might contribute to the progression of pressure overload dependent disease. Here, we aimed to elucidate whether pressure overload in the regenerative stage shortly after birth could lead to a more adaptive cardiac response than in the non-regenerative stage in mice.nTAC in the non-regenerative stage induced cardiac dysfunction, myocardial fibrosis and cardiomyocyte hypertrophy. In contrast, during induction of nTAC in the regenerative stage, cardiac function remained intact and this was associated with enhanced myocardial angiogenesis and innervation as well as increased cardiomyocyte proliferation, but neither hypertrophy nor fibrosis. Mechanistically, inhibition of cardiomyocyte proliferation and angiogenesis in nTAC in the regenerative phase by rapamycin triggered mortality and myocardial fibrosis, which both also similarly occurred upon inhibition of angiogenesis by PTK787, suggesting that both processes are essential for the adaptive cardiac response to nTAC. A comparative genome-wide transcriptomic analysis between hearts after nTAC in the regenerative versus the non-regenerative stage defined differentially expressed functional gene classes, and a related bioinformatics analysis suggested the transcription factor GATA4 as master regulator of the regenerative gene-program. Indeed, cardiomyocyte specific deletion of GATA4 converted the regenerative nTAC into a non-regenerative, maladaptive response.tablished a new model of neonatal pressure-overload in mice, which when applied in the regenerative postnatal stage, triggers a purely adaptive myocardial response. Employing this model to identify new regulators might lead to novel therapeutic strategies to combat pressure overload induced myocardial disease.
Project description:The expression of the small molecular weight heat shock protein (Hsp) H11 kinase/Hsp22 (Hsp22) is restricted to a limited number of tissues, including the heart and skeletal muscle, both in rodents and in humans. We generated a mouse knockout (KO) model, and investigated the role of Hsp22 in regulating cardiac hypertrophy in response to pressure overload. We compared gene expression profiles between WT and KO mice in basal condition and three days pressure overload after transverse aortic constriction (TAC). These data illustrated a novel mechanism of Hsp22-related gene expression in response to cardiac stress.
Project description:Myocardial deletion of klf4 sensitizes mouse to pressure overload. In order to gain a better understanding of molecular mechanisms of such alterations, we profiled gene expression before and after 3-day of pressure overload (induced by transverse aortic constriction -TAC) in the hearts from MHC-cre (Cre) control and MHC-cre-klf4-deficient (KO) mice. 10wk old male mice was subjected to transverse aortic constriction (TAC) to induce pressure overload or sham operation as control group. After 3 days, heart was removed and total RNA was extracted from apex and subjected for array analysis. Four animals in each group.
Project description:Myocardial deletion of klf4 sensitizes mouse to pressure overload. In order to gain a better understanding of molecular mechanisms of such alterations, we profiled gene expression before and after 3-day of pressure overload (induced by transverse aortic constriction -TAC) in the hearts from MHC-cre (Cre) control and MHC-cre-klf4-deficient (KO) mice.
Project description:To investiage the ability of positve inotropism from myocardial Rad reduction we induced Rad knockout after onset of pressure overload to reverse or compensate progression of heart failure
Project description:A molecular and bioinformatic pipeline permitting comprehensive analysis and quantification of myocardial miRNA and mRNA expression with next-generation sequencing was developed and the impact of enhanced PI3Kalpha signaling on the myocardial transcriptome signature of pressure overload-induced pathological hypertrophy was explored.
Project description:A molecular and bioinformatic pipeline permitting comprehensive analysis and quantification of myocardial miRNA and mRNA expression with next-generation sequencing was developed and the impact of enhanced PI3Kalpha signaling on the myocardial transcriptome signature of pressure overload-induced pathological hypertrophy was explored. miRNA and mRNA-Seq were carried out in four groups of mouse LV samples: WT sham, WT+TAC, caPI3Kalpha sham, caPI3Kalpha+TAC
Project description:Growth and transcriptional profiles of the barophilic methanarchaeon Methanocaldococcus jannaschii were studied at temperatures up to 98C and pressures up to 500 atm. Application of 500 atm of hyperbaric pressure shifted the optimal growth temperature upwards, and heat shock from 88C to 98C at 500 atm resulted in termination of growth. Pressure shock of M. jannaschii from 7.8 to 500 atm over 15-min, the first pressure upshift reported for a barophile, did not accelerate growth. Transcriptional profiles indicated a similar pressure response under growth and heat shock at 500 atm and pressure shock to 500 atm suggesting that the commonly affected genes are important for high-pressure adaptation. Factorial microarray design allowed de-convolution of the interacting effect of elevated pressure and heat shock on expression profiles, thus suggesting genes that may contribute to the organism’s survival in the turbulent in situ conditions of deep-sea hydrothermal vents. Keywords: stress response, time course, high pressure, heat shock, pressure shock