Project description:Pressure overload-induced cardiac hypertrophy was examined in IL-18 knockout and littermate control mice. Experiment Overall Design: 4 groups with RNA pooled from 5-6 per group. Role of IL-18 on gene expression in cardiac hypertrophy induced by pressure overload (transaortic constriction)
Project description:Pathological cardiac hypertrophy was induced by pressure overload on the heart. We performed genome-wide exon array experiments with left ventricles of mice with 1 week and 4 week of transverse aortic constriction (TAC). The exon level analysis revealed widespread regulation of alternative splicing and alternative polyadenylation during hypertrophy.
Project description:Pathological cardiac hypertrophy was induced by pressure overload on the heart. We performed genome-wide exon array experiments with left ventricles of mice with 1 week and 4 week of transverse aortic constriction (TAC). The exon level analysis revealed widespread regulation of alternative splicing and alternative polyadenylation during hypertrophy. Exon and gene expression changes were examined in 1 week and 4 week TAC-operated hearts compared to sham-operated hearts. We used C57/BL6 wildtype mice, and their left ventricles were subject to surgery (each n=2).
Project description:Expression profiles at various time points after surgical intervention for pressure-overload induced cardiac hypertrophy and failure.
Project description:An important event in the pathogenesis of heart failure is the development of pathological cardiac hypertrophy. In cultured cardiac cardiomyocytes, the transcription factor Gata4 is required for agonist-induced cardiomyocyte hypertrophy. We hypothesized that in the intact organism Gata4 is an important regulator of postnatal heart function and of the hypertrophic response of the heart to pathological stress. To test this hypothesis, we studied mice heterozygous for deletion of the second exon of Gata4 (G4D). At baseline, G4D mice had mild systolic and diastolic dysfunction associated with reduced heart weight and decreased cardiomyocyte number. After transverse aortic constriction (TAC), G4D mice developed overt heart failure and eccentric cardiac hypertrophy, associated with significantly increased fibrosis and cardiomyocyte apoptosis. Inhibition of apoptosis by overexpression of the insulin-like growth factor 1 receptor prevented TAC-induced heart failure in G4D mice. Unlike WT-TAC controls, G4D-TAC cardiomyocytes hypertrophied by increasing in length more than width. Gene expression profiling revealed upregulation of genes associated with apoptosis and fibrosis, including members of the TGF? pathway. Our data demonstrate that Gata4 is essential for cardiac function in the postnatal heart. After pressure overload, Gata4 regulates the pattern of cardiomyocyte hypertrophy and protects the heart from load-induced failure. Experiment Overall Design: We reasoned that if Gata4 was a crucial regulator of pathways necessary for cardiac hypertrophy, then modest reductions of Gata4 activity should result in an observable cardiac phenotype. To test this hypothesis, we used gene targeted mice that express reduced levels of Gata4. We characterized these mice at baseline and after pressure Experiment Overall Design: overload.
