Neuropilin-2 Identifies Cardiovascular Precursor Cells and is Required for Vascular Differentiation in Murine Embryonic Stem Cells System

Neuropilins are cell surface receptors that bind Class III semaphorins and Vascular Endothelial Growth Factor (VEGF). While Neuropilin-1 is essential for vascular development, the role of Neuropilin-2 is less well defined. The objective of this study was to determine the role of Neuropilin-2 in early cardiac and vascular differentiation in embryonic stem cells. We report that expression of Neuropilin-2 coincides temporally with Brachyury expression in murine embryonic stem cells and that Neuropilin-2 expression occurs in the majority of Brachyury positive cells. In contrast to Neuropilin-1, we found very few Neuropilin-2 positive cells that co-express the hemangioblast marker Flk-1. Both Neuropilin-2 positive and Brachyury positive cells express mesoderm markers that can differentiate into cardiomyocyte, endothelial and smooth muscle cell types with equivalent efficiency. However, inhibition of Neuropilin-2 expression impairs the differentiation of cardiovascular precursors to endothelial cells and smooth muscle cells, but not cardiomyocytes. The onset of Neuropilin-2 expression identifies a sub-population of Brachyury positive cardiovascular precursors that can differentiate to endothelial, smooth muscle and cardiomyocyte cell types. Furthermore, Neuropilin-2 is functionally required for differentiation of vascular cell types but not cardiomyocytes.