Ensembles of endothelial and mural cells promote angiogenesis in prenatal human brain.

Interactions between angiogenesis and neurogenesis regulate embryonic brain development. However, a comprehensive understanding of the stages of vascular cell maturation is lacking, especially in the prenatal human brain. Using fluorescence-activated cell sorting, single-cell transcriptomics, and histological and ultrastructural analyses, we show that an ensemble of endothelial and mural cell subtypes tile the brain vasculature during the second trimester. These vascular cells follow distinct developmental trajectories and utilize diverse signaling mechanisms, including collagen, laminin, and midkine, to facilitate cell-cell communication and maturation. Interestingly, our results reveal that tip cells, a subtype of endothelial cells, are highly enriched near the ventricular zone, the site of active neurogenesis. Consistent with these observations, prenatal vascular cells transplanted into cortical organoids exhibit restricted lineage potential that favors tip cells, promotes neurogenesis, and reduces cellular stress. Together, our results uncover important mechanisms into vascular maturation during this critical period of human brain development.
Competing Interests: Author contributions E.E.C. and E.J.H. conceived the project and designed the experiments. E.E.C. performed immunohistochemistry and quantification of blood vessel density, FACS experiments, 2D culture experiments, and organoid transplants. A.C.-S., S.G.-G., J.M.G.-V., and A.A.-B. performed and analyzed TEM data. A.B., L.N.D., J.O.B., C.E.H., and C.S.-E. performed bioinformatics. A.B. and U.C.E. performed RNA velocity analysis. M.G.A. and J.M.R. performed organoid experiments and L.N.D. and K.W-P. analyzed the results with supervision from E.E.C., J.C., and L.N.D. performed FACS experiments and E.J.V. performed mitochondrial quantifications. N.K.B. and K.N. performed and analyzed the Seahorse experiments. C.M., J.F.L., and M.V. contributed to the collection and preparation of human tissues. M.H. designed the web browser. M.F.P. and A.R.K. contributed reagents and expertise. E.E.C. and E.J.H. wrote the manuscript with inputs from all authors. Declaration of interests A.R.K. and A.A-B. are founding members of Neurona Therapeutics.
(Published by Elsevier Inc.)