Single cell RNA sequencing and lineage tracing confirm mesenchyme to epithelial transformation (MET) contributes to repair of the endometrium at menstruation

We profile the transcriptomes of over 20,000 mouse single cells, yielding molecular definitions for mesenchymal and epithelial cell types present in the mouse uterus during post-menstrual tissue repair. We identify a novel population of fibroblasts that express genetic markers associated with both mesenchymal and epithelial phenotypes in the repairing mouse uterus. Further trajectory analysis indictates a differentiation trajectory between mesenchymal and epithelial cells indicative of a putative mesenchymal-to-epithelial transition (MET) event occuring during post-menstrual tissue repair. Our work provides a platform to further understand the roles of these cell populations in uterine physiology and disease and for comparisons between wound healing events in the endometrium and other adult tissue which are prone to fibrosis. Overall design: 10X Genomics Single cell 3' gene expression V3