Institute for Molecular Bioscience, University of Queensland
Perivascular and mural cells of the vertebrate brain maintain vascular integrity, modulate vessel function, contribute in stroke and are involved in the maintenance of neural stem cells. Despite these functions, the origins, diversity and many roles of perivascular and mural cells remain to be fully understood. Along with two other groups, we have recently published that mural lymphatic endothelial cells (muLECs) are present in the meninges of zebrafish, modulate meningeal angiogenesis and can take up acetylated low density lipoprotein (LDL) from the blood stream and macromolecules from the parenchyma. These cells arise by lymphangiogenesis, and express many lymphatic endothelial cell (LEC) markers (including Lyve1 and Mrc1), however they do not form vessels and remain as single mural cells closely apposed to blood vessels in the meninges. The question of whether these cells are conserved has remained unanswered. Analysis of the mouse meninges reveals a population of Lyve1/Mrc1 positive cells that are also closely apposed to blood vessels and can take up LDL. Lineage tracing based on Cdh5-Cre Tdtomato identified cells that are Lyve1 positive and derived from the endothelium. We have used an unbiased approach to accurately profile all scavenger lineages of the mouse meninges. Single cell sequencing was performed on 16000 cells with the 10x Genomics Chromium platform. Clustering analysis revealed scavengers with similarities and differences to muLECs. Moreover, these studies suggest a local haemogenic endothelial source in the meninges yet to be fully appreciated.