Figure 7.

Proposed model for MN-EC communication required for proper spinal cord vascularization and MN development

(A) At E11.5 , MN columns of WT embryos are avascular. MN-secreted Sema3C signals to PlexinD1/NRP1 in ECs, controlling their ingression into MN columns, thereby allowing proper MN development and maturation. However, in EC-specific PlexinD1 or MN-specific Sema3C mutants, this signaling is interrupted and BVs ingress into MN columns prematurely. MN development is impaired showing defects in axon organization at their exit into to the periphery at E11.5. (B) At E18.5 , MNs of embryos where PlexinD1 signaling in ECs is absent show dysregulated expression of terminal differentiation markers and functional factors.