Figure 3. Organizing principles of human brain mural cells.

a, UMAP of 34,508 human pericyte and smooth muscle cell nuclei, colored by cell subtype. aSMC = arterial smooth muscle cell (aSMC), aaSMC = arteriole SMCs, T-Pericyte = solute transport pericytes, and M-Pericyte = Extracellular matrix regulating pericytes.

b, Enriched biological pathways in T- and M-pericytes compared to remaining SMC and pericyte populations (P value < 0.05, cumulative hypergeometric test).

c, Heatmap of gene expression in human SMCs and pericytes. Solid line delineating aaSMC/aSMCs from pericytes reflects an abrupt transcriptomic transition. Note that unlike BECs, mural cell ordering does not reflect anatomical arteriovenous ordering.

d, Mapping expression of mouse mural cell markers onto human mural cell types. The top 500 mouse markers were aggregated into four distinct modules (‘aSMCs’, ‘aaSMCs’, capillary ‘pericytes’, venous smooth muscle cells ‘vSMCs’)¹² and their expression assessed in the four transcriptionally distinct human mural cell types.

e, Overlap between the top 100 human endothelial and mural cell subtype markers and those identified in mice. A more lenient set of 500 mouse markers¹² was used for comparison for robust results. Note that species-conservation of a cell type marker depends on species-specific changes in the given cell type and changes among remaining cell types.