Physical Binding of Endothelial MCAM and Neural Transmembrane Protease Matriptase—Novel Cell Adhesion in Neural Stem cell Vascular Niche

• Main Authors: Hsiu-Hui Tung, Sheau-Ling Lee
• Format: Article
• Language: English
• Published: Nature Publishing Group 2017-07-01
• Series: Scientific Reports
• Online Access: https://doi.org/10.1038/s41598-017-05131-4

Abstract Brain neural stem cells and transit amplifying cells in the subventricular zone (SVZ) of the lateral ventricles are in direct contact with the microvascular endothelium. The mechanisms/molecules of direct cell contact in the SVZ neurovascular niche are not fully understood. We previously showed that neural stem/progenitor (NS/P) cells induce brain endothelial signaling in direct cell contact through matriptase (MTP) on NS/P cell surface. In the present study, using pull-down and LC-MS/MS, we identified melanoma cell adhesion molecule (MCAM) the brain endothelial molecule that interacts with MTP. MCAM physically binds to the CUB domains of MTP and induces a chain of brain endothelial signaling including p38MAPK activation, GSK3β inactivation and subsequently β-catenin activation; none of these signaling events occurred when either MTP or MCAM is deleted. MTP-MCAM binding and induction of endothelial signaling were all sensitive to cholera toxin. Together, we identified key molecules that may represent a mechanism in neural stem cell vascular niche regulation.