FIGURE 1.

Single-cell transcriptomic analysis of endometrium. (A) Experimental design of the study. (B) UMAP presentation of endometrial cell clusters. Although the fibroblast-like population contained the highest numbers of cells, there also are prominent groups of T cells, NK cells, endothelial cells and unciliated and ciliated epithelial cells. (C) Dot plot of identified markers of each cell type. (D) Pie chart showing percentages of identified cell types. (E) Bar graph showing the number of cells from each patient (n = 3) in each cluster of integrated data. Each patient sample contributed data to each cluster. (F) Heatmap of highly expressed genes compared between progenitor cells, fibroblast-like cells, SMCs, and matrix Gla protein (MGP)-expressing fibroblasts. Ciliated epithelial cells highly expressed cilia-associated genes such as TPPP3, PIFO, and RSPH1. (G) Feature plots showing the distribution of key messenger RNAs s such as estrogen and progesterone receptors and select ECM-associated genes in fibroblast-like cells. (H) Pseudotime trajectory that was started from pericytes. It appeared that the pericytes might differentiate to the fibroblast-like group, including E0/E1/E11/E13, a process terminated in ciliated epithelial cells, which suggested mesenchymal–epithelial transition. (I) Heatmap of the PROGENy-predicted pathway activity scores of selected clusters (ciliated epithelial cells, pericytes, fibroblast-like cells, VSMCs). Interestingly, estrogenic and WNT pathways were upregulated in most fibroblast-like cells and downregulated in ciliated epithelial cells. UMAP, uniform manifold approximation and projection; SMCs, smooth muscle cells; VSMCs, vascular smooth muscle cells.