Project description:Aims: Cardiomyocyte-specific nitric oxide synthase 3 (NOS3) overexpression reduces left ventricular (LV) remodelling after myocardial infarction in mice, but its effect on sustained LV pressure-overload remains incompletely understood. We investigated LV structural and functional adaptation to elevated afterload in mice with cardiomyocyte-restricted NOS3 overexpression (NOS3TG) and wild type littermates (WT). Methods and Results: Hemodynamic indices, cardiac hypertrophy and interstitial fibrosis were measured 10 weeks after transverse aortic constriction (TAC). After 10 weeks TAC, NOS3TG had better preserved systolic function (maximum rates of pressure development normalized to maximal pressure 77±6 versus 65±2 ms-1, P=0.05), reduced heart weight-body weight ratio (HW/BW, 5.0±0.3 versus 5.8±0.1, P<0.05), and cardiomyocyte width than WT (14.9±0.4 vs 16.7±0.2 ?m, P<0.05). After 10 weeks TAC, a 44k cDNA chip-based microarray analysis was validated using real time PCR and revealed significantly altered expression pattern of genes involved in cellular growth, matrix remodelling, and inflammation between genotypes. Conclusions: Cardiomyocyte-restricted NOS3 overexpression attenuates TAC-induced hypertrophy via autocrine inhibition of cardiomyocyte cell growth, but does not mitigate myocardial fibrosis. The subsequent diastolic dysfunction suggests that inhibition of matrix producing cells during hypertrophic stress is necessary to prevent functional and structural deterioration of the pressure-overloaded heart. Left ventricular mRNA expression profiles were compared between alpha-myosin heavy chain driven nitric oxide synthase 3 (alpha-MHC-NOS3) transgenic and wild type (WT) littermate mice at baseline and 10 weeks after transversal aortic constrcition-induced pressure-overload. Biological repeats: n=4, two males and two females, for each group and condition. Transgenic mice were backcrossed for seven generations (F7) to a C57Bl/6 N background and age and weight matched animals were used for microarray experiments.
Project description:Aims: Cardiomyocyte-specific nitric oxide synthase 3 (NOS3) overexpression reduces left ventricular (LV) remodelling after myocardial infarction in mice, but its effect on sustained LV pressure-overload remains incompletely understood. We investigated LV structural and functional adaptation to elevated afterload in mice with cardiomyocyte-restricted NOS3 overexpression (NOS3TG) and wild type littermates (WT). Methods and Results: Hemodynamic indices, cardiac hypertrophy and interstitial fibrosis were measured 10 weeks after transverse aortic constriction (TAC). After 10 weeks TAC, NOS3TG had better preserved systolic function (maximum rates of pressure development normalized to maximal pressure 77±6 versus 65±2 ms-1, P=0.05), reduced heart weight-body weight ratio (HW/BW, 5.0±0.3 versus 5.8±0.1, P<0.05), and cardiomyocyte width than WT (14.9±0.4 vs 16.7±0.2 ?m, P<0.05). After 10 weeks TAC, a 44k cDNA chip-based microarray analysis was validated using real time PCR and revealed significantly altered expression pattern of genes involved in cellular growth, matrix remodelling, and inflammation between genotypes. Conclusions: Cardiomyocyte-restricted NOS3 overexpression attenuates TAC-induced hypertrophy via autocrine inhibition of cardiomyocyte cell growth, but does not mitigate myocardial fibrosis. The subsequent diastolic dysfunction suggests that inhibition of matrix producing cells during hypertrophic stress is necessary to prevent functional and structural deterioration of the pressure-overloaded heart.
Project description:To describe the transcriptional changes associated with polymicrobial-sepsis induced myocardial depression in wild type and iNOS deficient mice. Keywords: myocardium, contractility, differential gene expression, nitric oxide synthase, infection We compared the transcriptional profile of C57/BL6 WT mice and congenic B6 129P2-Nos2tm1Lau/J mice after 48 hrs of polymicrobial sepsis induced by caecal ligation and perforation. 48 hours after surgery, mice were anaesthetised (intraperitoneal 100 mg/kg ketamine and 10 mg/kg xylazine). The right common carotid artery was cannulated (Millar Mikro-Tip pressure transducing catheter: 1.4F sensor, 2F catheter; Houston TX). Pressure tracings from the aorta and left ventricle were recorded (SonoLAB software; Sonometrics Corp., London Ontario Canada) and analysed using Cardiosoft and Origin 6.0 (Sonometrics Corp., and Microcal Software, Northampton MA). The heart was removed, emptied of blood, and snap frozen.
Project description:The dysfunction of endothelial nitric oxide synthase may be involved in development of atherosclerosis; however, the underlying molecular and cellular mechanisms of atherosclerosis are poorly understood. Here, we investigated gene expressionsin relation to atherosclerosis using endothelial nitric oxide synthase (eNOS)-deficient mice.
Project description:Blood pressure regulation is known to be maintained by a neuro-endocrine circuit, but whether immune cells contribute to blood pressure homeostasis has not been determined. We previously showed that CD4+ T lymphocytes that express choline acetyltransferase (ChAT), which catalyzes the synthesis of the vasorelaxant acetylcholine, relay neural signals. Here we show that these CD4 +CD44hiCD62L lo T helper cells by gene expression are a distinct T-cell population defined by ChAT (CD4 TChAT). Mice lacking ChAT expression in CD4+ cells have elevated arterial blood pressure, compared to littermate controls. Jurkat T cells overexpressing ChAT (JTChAT) decreased blood pressure when infused into mice. Co-incubation of JTChAT and endothelial cells increased endothelial cell levels of phosphorylated endothelial nitric oxide synthase, and of nitrates and nitrites in conditioned media, indicating increased release of the potent vasorelaxant nitric oxide.
Project description:The purpose of this study is to comprehensively elucidate the role of nitric oxide and nitric oxide synthase isoforms in pulmonary emphysema using cap analysis of gene expression (CAGE) sequencing.
Project description:Aim was to investigate the effect of cardiomyocyte-specific expression of the human Relaxin Family Peptide Receptor 1 (RXFP1) in a mouse model of pressure-overload induced cardiac dysfunction (TAC). Mice overexpressing the hRXFP1 receptor (or non-transgenic controls) underwent TAC (or Sham) surgery and were followed up for 8 weeks. Heart was removed and RNA isolated from left ventricle to perform bulk RNAseq.