GATA2 Promotes Hematopoietic Development and Represses Cardiac Differentiation of Human Mesoderm

Summary: In vertebrates, GATA2 is a master regulator of hematopoiesis and is expressed throughout embryo development and in adult life. Although the essential role of GATA2 in mouse hematopoiesis is well established, its involvement during early human hematopoietic development is not clear. By combining time-controlled overexpression of GATA2 with genetic knockout experiments, we found that GATA2, at the mesoderm specification stage, promotes the generation of hemogenic endothelial progenitors and their further differentiation to hematopoietic progenitor cells, and negatively regulates cardiac differentiation. Surprisingly, genome-wide transcriptional and chromatin immunoprecipitation analysis showed that GATA2 bound to regulatory regions, and repressed the expression of cardiac development-related genes. Moreover, genes important for hematopoietic differentiation were upregulated by GATA2 in a mostly indirect manner. Collectively, our data reveal a hitherto unrecognized role of GATA2 as a repressor of cardiac fates, and highlight the importance of coordinating the specification and repression of alternative cell fates. : Giorgetti A. and colleagues demonstrate that GATA2 induction in early mesodermal cells leads to the robust generation of hemogenic endothelial and hematopoietic cells from human iPSCs. They show the ability of GATA2 to instruct mesodermal precursors toward a hematopoietic cell fate and concurrently inhibit cardiac fates. This study expands our understanding of the regulatory networks that control early human hematopoiesis. Keywords: GATA2, human iPSCs, hemogenic specification, hematopoiesis, mesoderm diversification, cardiac development