Abstract 1017: Post-translational Modification Of GATA-4 Involved In The Differentiation Of Monkey ES Cell Into Cardiac Myocytes
Transplantation of embryonic stem (ES) cells into infracted myocardium has been shown to preserve left ventricular function in rodents. Before application of ES cell therapy in humans, however, it is critical to perform pre-clinical studies in large animals such as primates. Characteristics of cynomolgus monkey ES cells are similar with those of human ES cells, but quite different from those of mouse ES cells. Differentiation of Embryonic stem (ES) cells into cardiac myocytes requires activation of a cardiac-specific gene program. Histone acetytrans-ferases (HATs) and Histone deactylases (HDACs) govern gene expression patterns by being recruited to the target genes through association with specific transcription factors. One of the HATs, p300, serves as a coactivator of cardiac-specific transcription factors such as GATA-4. The HAT activity of p300 is required for actylation and DNA binding of GATA-4 and its full transcription activity as well as for promotion of a transcriptionally active chromatin configuration. The role of HATs and HDACs in post-translational modification of GATA-4 during the differentiation of monkey ES cells into cardiac myocytes remained unknown. In an ES cell model of developing embryonic bodies, an acetylated form of GATA-4 and its DNA binding increased concomitantly with the expression of p300 during the differentiation of ES cells into cardiac myocytes. Treatment of ES cells with trichostatin A (TSA), a specific HDAC inhibitor, induced acetylation of histone-3/4 near GATA sites within the atrial natriuretic factor promoter. In addition, TSA augmented the increase in an acetylated form of GATA-4 and its DNA binding during the ES cell differentiation. TSA facilitate the expression of endogenous cardiac β-myosing heavy chain during the differentiation. These findings demonstrate that acetylation of GATA-4 as well as of histone are involved in the differentiation of monkey ES cells into cardiac myocytes.