Single-cell RNA sequencing data analysis. Ziegler et al. discovered ACE2 and TMPRSS2 co-expressing cells in nasal goblet secretory cells, lung type II pneumocytes, and ileal absorptive enterocytes through scRNA-seq database analyses . Subsequently, we analyzed the RNA expression of 1,588 nodes previously obtained from the highconfidence PPi network using different single-cell databases from the Alexandria Project.