In addition to these four brain cell types, we also included an endothelial protein marker list derived from RNAseq data of purified brain endothelial cells (Zhang et al., 2014b) to examine endothelial cell type enrichment, given the known effects of ApoE polymorphism on vascular biology and cerebrovascular disease (Bell et al., 2012; Schilling et al., 2013; Tai et al., 2016; Bouchareychas and Raffai, 2018). This evidence concerns the gene APOE and cerebrovascular disorder.