Single Cell RNA-sequencing of mammary gland epithelial cells

The mammary gland epithelium is composed of basal cells (BC) and luminal cells (LC). Lineage tracing demonstrates that many glandular epithelia initially develop from multipotent basal stem cells (BaSCs) that are replaced in adult life by distinct pool of unipotent stem cells. However, adult unipotent BaSC can reactivate multipotency and give rise to LCs upon transplantation or oncogene expression, demonstrating the important plasticity of BaSCs in regenerative and pathological conditions, and suggesting that an active mechanism restricts multipotency in BaSCs during physiological conditions. Here, we assess whether basal and luminal cell-cell communication restricts multipotency in glandular epithelia. Overall design: The purpose of this study was to define, at the single cell level, the transcriptional profile of murine mammary gland epithelial cells upon ablation of luminal cells. Particularly, we identified the enrichment of one intermediate population between basal and luminal cells, that shares genes with both basal and luminal cells. The aim of this study was to better characterize this population and understand the lineage trajectory followed by the basal cell, hybrid and newly formed luminal cells. In this experiment, we used mammary gland epithelial cells FACS sorted based on the negative expression of CD140a, CD45 and CD31 and the positive expression of Tomato, CD29 and EpCAM before and after ablation of luminal cells.