Developmental stage‐specific contribution of <scp>LGR5</scp>⁺ cells to basal and luminal epithelial lineages in the postnatal mammary gland

TLDR

LGR5 is a marker of cycling stem cells in several epithelial tissues, including the small intestine, colon, stomach, and hair follicle. The study aims to determine whether LGR5 marks mammary epithelial stem cells. The authors performed in situ lineage‑tracing and mammary gland reconstitution using LGR5‑expressing epithelial cells. During the first 12 days of postnatal development, LGR5 progeny shift from the luminal to the myoepithelial compartment, demonstrating a stage‑specific contribution of LGR5‑expressing cells to both luminal and basal lineages. © 2012 Pathological Society of Great Britain and Ireland.

Abstract

Abstract The leucine‐rich repeat‐containing heterotrimeric guanine nucleotide‐binding protein‐coupled receptor 5 ( LGR5 ) has been identified as a marker of cycling stem cells in several epithelial tissues, including small intestine, colon, stomach and hair follicle. To investigate whether LGR5 also marks mammary epithelial stem cells, we performed in situ lineage‐tracing studies and mammary gland reconstitutions with LGR5 ‐expressing mammary epithelial cells. Interestingly, the LGR5 progeny population in mammary epithelium switches from the luminal to the myoepithelial compartment during the first 12 days of postnatal development, likely reflecting local changes in Wnt signalling. Together, our findings point to a stage‐specific contribution of LGR5 ‐expressing cells to luminal and basal epithelial lineages during postnatal mammary gland development. Copyright © 2012 Pathological Society of Great Britain and Ireland.