Figure 4: TZ-derived cells adopt a progenitor state during SNEC formation.
A) Clustering of Krt7hi cells combined from all 3 timepoints analyzed via scRNA-Seq; UMAP visualization reveals a distinct cluster (#3) containing wound associated squamous cells (WASCs). B) Plot of cell count per cluster shows that cluster #3 predominantly mapped to Krt7hi cells at exp d 7. C) Enriched genes in WASCs include Ly6a, Krt17, and Ass1. D) Leading edge cells at exp d 6 and proximal rete pegs in SNEC at exp 15 (blue lines) exhibit high expression of Ly6a (Sca-1) mRNA. Ly6a expression is reduced prior to injury and after repair. Orange line denotes the dentate line. E) Leading edge cells (blue line) in SNEC selectively express Ass1 mRNA during injury. F) Gene set enrichment analysis (GSEA) of WASC marker genes demonstrates enrichment of ribosomal, translational, and stem cell pathways. G) Enrichment plots demonstrate upregulation of fetal intestinal genes in WASCs and reprogrammed colonocytes. H) Heatmap of aggregate fetal intestinal gene expression in different types of epithelial cells at exp d 0, 7, or 42 (paired t-tests, Holm-Bonferroni correction to compute adjusted P value as “Q value”). I) Significant MSigDB/Hallmark pathways from GSEA comparing the effect of DSS-induced injury on colonic epithelium vs. TZ-derived cells at exp d 7. The inflammatory response is more pronounced in colonic epithelium.