NRP2 and infection: This strategy provided a means to: (1) discover that BEC to endfoot signaling is ample and dynamic, and depends on peripheral events like infections that can modulate existing BEC-endfoot signaling pathways, but also induce others (Figs. 3 and 4), and (2) identify hundreds of BEC-endfoot ligand-receptor pairs that are present in the same cells of human post-mortem brains, with some of them being altered in neurodegenerative conditions, such as semaphorins-NRP2 (Figs. 7 and 8).