Flow-induced Protein Kinase A / CREB pathway acts via BMP signaling to promote AGM hematopoiesis

By chemical modulation of the PKA/CREB and BMP pathways in isolated AGM VE-cadherin+ cells from mid-gestation embryos, we demonstrate that PKA/CREB regulates hematopoietic engraftment and clonogenicity of hematopoietic progenitors and is dependent on secreted BMP ligands through the type I BMP receptor. We used microarray to document upregulation of PKA/CREB-BMP pathway as well as global BMP target upregulation upon PKA/CREB activation. Isolated VE+ cells from E11.5 AGM were treated with BMP4 (4ng/ml), forskolin (25uM) or both for 8 hours before RNA isolation.