E-GEOD-5500 - Transcription profiling of hearts from mice heterozygous for Gata4 mutation (G4D) to investigate the significance of Gata4 in regulating postnatal heart function and in regulating the hypertrophic response of the heart to pathological stress
Released on 13 November 2007, last updated on 30 April 2015
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.
transcription profiling by array, co-expression, stimulus or stress, strain or line
Gata4 is required for maintenance of postnatal cardiac function and protection from pressure overload-induced heart failure. Egbert Bisping, Sadakatsu Ikeda, Sek Won Kong, Oleg Tarnavski, Natalya Bodyak, Julie R McMullen, Satish Rajagopal, Jennifer K Son, Qing Ma, Zhangli Springer, Peter M Kang, Seigo Izumo, William T Pu.