BioProject

Endothelial cells and macrophages are known to engage in tight and specific interactions that contribute to the modulation of vascular function. More...

Endothelial cells and macrophages are known to engage in tight and specific interactions that contribute to the modulation of vascular function. Here we show that adult endothelial cells provide critical signals for the selective growth and differentiation of macrophages from several types of hematopoietic progenitor cells. The process features the formation of well-organized colonies that exhibit progressive differentiation from the center to the periphery and towards an M2-like phenotype, characterized by enhanced expression of Tie2 and CD206/Mrc1. These colonies are long-lived as long as the contact with the endothelium is maintained; removal of the endothelial monolayer results in rapid dissolution of the macrophage colonies. Not only the maintenance but also the formation of the colonies is strictly dependent on endothelial contact. We further found that M-CSF produced by the endothelium is critical for the expansion of the macrophage colonies and that blockade of M-CSF receptor impairs colony growth. Functional analyses indicate that these macrophages are capable of accelerating angiogenesis, promoting tumor growth and effectively engaging in tight associations with endothelial cells in vivo. These findings uncover a critical role of endothelial cells in the induction of macrophage differentiation and their ability to promote further polarization towards a proangiogenic phenotype. Overall design: 8 samples were sequenced: bone marrow derived macrophages (BMDM) were stimulated with LPS, IL4, or none. Colony cells induced by endothelial cells for 7 days. Each was duplicated. Less...