Single Cell RNA Sequencing of Human Milk-Derived Cells Reveals Sub-Populations of Mammary Epithelial Cells with Molecular Signatures of Progenitor and Mature States: a Novel, Non-invasive Framework for Investigating Human Lactation Physiology

AbstractCells in human milk are an untapped source, as potential “liquid breast biopsies”, of material for investigating lactation physiology in a non-invasive manner. We used single cell RNA sequencing (scRNA-seq) to identify milk-derived mammary epithelial cells (MECs) and their transcriptional signatures in women with diet-controlled gestational diabetes ( GDM) with normal lactation. Methodology is described for coordinating milk collections with single cell capture and library preparation via cryopreservation, in addition to scRNA-seq data processing and analyses of MEC transcriptional signatures. We comprehensively characterized 3740 cells from milk samples from two mothers at two weeks postpartum. Most cells (>90%) were luminal MECs (luMECs) expressing  lactalbumin alpha andcasein beta and positive forkeratin  8 andkeratin  18. Few cells werekeratin  14+ basal MECs and a small immune cell population was present (<10%). Analysis of differential gene expression among clusters identified six potentially distinct luMEC subpopulation signatures, suggesting the potential for subtle functional differences among luMECs, and included one cluster that was positive for both progenitor markers and mature milk transcripts. No expression of pluripotency markersPOU class 5 homeobox 1 (POU5F1,  encoding OCT4)SRY-box transcription factor 2(SOX2) ornanog homeobox (NANOG), was observed. These observations were supported by flow cytometric analysis of MECs from mature milk s...
Source: Journal of Mammary Gland Biology and Neoplasia - Category: Cancer & Oncology Source Type: research