Background-Recent data suggest that GATA-4 is an antiapoptotic factor required for adaptive responses and a key regulator of hypertrophy and hypertrophy-associated genes in the heart. As a leading cause of chronic heart failure, reversal of postinfarction left ventricular remodeling represents an important target for therapeutic interventions. Here, we studied the role of GATA-4 as a mediator of postinfarction remodeling in rats. Methods and Results-Myocardial infarction, caused by ligating the left anterior descending coronary artery, significantly decreased the DNA binding activity of GATA-4 at day 1, whereas at 2 weeks the GATA-4 DNA binding was significantly upregulated. To determine the functional role of GATA-4, peri-infarct intramyocardial delivery of adenoviral vector expressing GATA-4 was done before left anterior descending coronary artery ligation. Hearts treated with GATA-4 gene transfer exhibited significantly increased ejection fraction and fractional shortening. Accordingly, infarct size was significantly reduced. To determine the cardioprotective mechanisms of GATA-4, myocardial angiogenesis, rate of apoptosis, c-kitϩ cardiac stemlike cells, and genes regulated by GATA-4 were studied. The number of capillaries and stemlike cells was significantly increased, and decreased apoptosis was observed. Conclusion-These results indicate that the reversal of reduced GATA-4 activity prevents adverse postinfarction remodeling through myocardial angiogenesis, antiapoptosis, and stem cell recruitment. GATA-4 -based gene transfer may represent a novel, efficient therapeutic approach for heart failure. (Circ Heart Fail. 2010;3:440-450.)Key Words: myocardial infarction Ⅲ heart failure Ⅲ angiogenesis Ⅲ gene therapy A dverse left ventricular (LV) remodeling after myocardial infarction (MI) is a major cause of heart failure (HF) and death. [1][2][3] The molecular mechanisms of post-MI remodeling process are not fully understood but involve alterations in specific signaling molecules, transcription factors (TFs), and their respective downstream pathways. 3 GATA-4 is a zincfinger TF that functions as a key regulator of numerous cardiac genes, such as atrial natriuretic peptide, B-type natriuretic peptide, ␣-myosin heavy chain, and -myosin heavy chain. 4 GATA-4 is also critical for cardiac development, as homozygous GATA-4 -deficient embryos die within 7 to 10 days post coitum owing to defects in ventral morphogenesis and heart tube formation. 5,6 Studies of alleles that cause partial loss of GATA-4 function and conditional deletion of GATA-4 have demonstrated it necessary also for the later phases of heart development and morphogenesis. [7][8][9] Mutations in the human GATA-4 gene have been identified as genetic causes of congenital heart disease. 10,11 In the adult heart, GATA-4 seems to have a unique dual role, on the 1 hand as a mediator of the hypertrophic response and as a survival factor on the other. GATA-4 is required for cardiomyocyte response to hypertrophic stimuli 12 and has been suggested as a nuclea...