CD9 and Hepatic fibrosis: Ramachandran et al. profiled transcriptomics of over 100,000 human liver cells from healthy and cirrhotic individuals, identified different cell types present in the liver, and uncovered novel subpopulations of macrophages (characterized by the expression of TREM2 and CD9) and endothelial cells (expressed ACKR1 and PLVAP) that are associated with liver fibrosis, thus enabling the discovery of therapeutic targets [90].