Figure 1.

ACE2 and Other Entry Factors Are Expressed in the Choroid Plexus

(A) Dot plot showing average expression and percentage of cells expressing SARS-CoV-2 entry factors ACE2 and TMRPSS2 in the five main clusters identified by scRNA-seq of days 27–53 ChP and day 55 telencephalic organoids (Pellegrini et al., 2020).

(B) Allen Brain Atlas expression data of ACE2 (probe names: ACE2 A_23 and ACE2 CUST_16267) in different adult human brain regions, with highest expression in the ChP. Regions with an average Z score across the two probes (black line) of greater than 1 are shown.

(C) Uniform Manifold Approximation and Projection (UMAP) plot showing subclustering of all ChP cell types identified by scRNA-seq. Imm ChP, immature ChP; lipid prod ChP, lipoprotein-producing ChP; Mat ChP, maturing ChP; NC, neural crest.

(D) Dot plot showing average expression and percentage of cells for key marker genes present in the subclusters identified by scRNA-seq. Lipoprotein-producing ChPs express SARS-CoV-2 entry genes ACE2, TMPRSS2, and TMPRSS4.

(E) Feature plot showing all cells expressing any level of ACE2.

(F) UMAP plot of mouse embryonic and adult ChP cells (left) and feature plot for ApoJ (clusterin).

(G) Immunoblot for ACE2, APOJ, and the loading control β-actin of days 33–53 ChP organoid protein lysates.

(H) Exponentially Modified Protein Abundance Index (emPAI) values for lipid-related proteins in a previously published dataset (Pellegrini et al., 2020) of organoid CSF samples until day 146.

(I) Representative confocal images of day 40 ChP tissue immunostained for the ChP epithelial marker HTR2C (serotonin receptor 2C) in magenta and ACE2 in green. Nuclei in blue are stained with DAPI. Scale bar: 50 μm.

(J) gProfileR (Reimand et al., 2011) analysis of genes co-expressed with ACE2 showing significant enrichment (p < 0.05) for GO categories cellular component (GO:CC), molecular function (GO:MF), and biological process (GO:BP).