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:Targeting cardiac remodeling is regarded as a key therapeutic strategy for heart failure. Kielin/chordin-like protein (KCP) is a secretory protein with 18 cysteine-rich domains and associated with kidney and liver fibrosis. However, the relationship between KCP and cardiac remodeling remains unclear. Here, we aimed to investigate the role of KCP in cardiac remodeling induced by pressure overload and explore its potential mechanisms. Left ventricular (LV) KCP expression was measured with real-time quantitative PCR, western blotting, and immunofluorescence staining in pressure overload-induced cardiac remodeling in mice. Cardiac function and remodeling were evaluated in wide-type (WT) mice and KCP knockout (KO) mice by echocardiography, which were further confirmed by histological analysis with hematoxylin and eosin and Masson staining. RNA sequence was performed with LV tissue from WT and KO mice to identify differentially expressed genes and related signaling pathways. Primary cardiac fibroblasts (CFs) were used to validate the regulatory role and potential mechanisms of KCP during fibrosis. KCP was down-regulated in the progression of cardiac remodeling induced by pressure overload, and was mainly expressed in fibroblasts. KCP deficiency significantly aggravated pressure overload-induced cardiac dysfunction and remodeling. RNA sequence revealed that the role of KCP deficiency in cardiac remodeling was associated with cell division, cell cycle, and P53 signaling pathway, while cyclin B1 (CCNB1) was the most significantly up-regulated gene. Further investigation in vivo and in vitro suggested that KCP deficiency promoted the proliferation of CFs via P53/P21/CCNB1 pathway. Taken together, these results suggested that KCP deficiency aggravates cardiac dysfunction and remodeling induced by pressure overload via P53/P21/CCNB1 signaling in mice.
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