Project description:Skin-mammary specific knockout (SSKO) of Pygo2 (K14-cre; Pygo2 flox/-) , a WNT signaling co-activator, results in defective mouse mammary gland development. The FACS sorted mammary stem cell (MaSC)/basal population from Pygo2 SSKO mammary gland displays biased differentiation towards luminal/alveolar lineage in vitro, and reduced regeneration rate of new mammary gland in vivo To gain the insight into gene expression profiles in control and Pygo2 SSKO mammary epithelial cells (MECs), we sorted the freshly isolated mouse MECs into MaSC/basal (Lin-CD29hiCD24+) and mature luminal population (Lin-CD29lowCD24+CD61-), and extract total RNA for cDNA microarray analysis
Project description:Skin-mammary specific knockout (SSKO) of Pygo2 (K14-cre; Pygo2 flox/-) , a WNT signaling co-activator, results in defective mouse mammary gland development. The FACS sorted mammary stem cell (MaSC)/basal population from Pygo2 SSKO mammary gland displays biased differentiation towards luminal/alveolar lineage in vitro, and reduced regeneration rate of new mammary gland in vivo
Project description:The Mammary gland undergoes complicated epithelial remodeling to form lobuloalveoli during pregnancy, in which basal epithelial cells remarkably increase to form a basket-like architecture. However, it remains largely unknown how dormant mammary basal stem/progenitor cells involve in lobuloalveolar development. Here, we show that Nfatc1 expression marks a rare population of mammary epithelial cells with the majority being basal epithelial cells. Nfatc1 reporter-marked basal epithelial cells are relatively dormant mammary stem/progenitor cells. Although Nfatc1 reporter-marked basal epithelial cells show limited contribution to the homeostasis of mammary epithelium, they divide rapidly during pregnancy and contribute to lobuloalveolar development. Furthermore, Nfatc1 reporter-marked basal epithelial cells are preferentially used for multiple pregnancies. Using single-cell RNA-seq analysis, we identify multiple functionally distinct clusters within the Nfatc1 reporter-marked cell-derived progeny cells during pregnancy. Taken together, our findings underscore Nfatc1 reporter-marked basal cells as dormant stem/progenitor cells that contribute to mammary lobuloalveolar development during pregnancy.
Project description:The aim of the experiment was to analyse gene expression profiles in Brca1 tumours arising from different mammary epithelial cell populations use a Cre-loxP based conditional knockout system. K14 promoter driving Cre expression caused Brca1 knockout in basal stem cells and thus stem cell origin tumours whereas Blg promoter driving Cre expression caused Brca1 knockout in luminal progenitor cells and thus progenitor origin tumours. Individual arrays were carried out on labelled cDNA made from RNA isolated from mouse mammary tumours. Only cDNA passing Almac diagnostics QC criteria were hybridised to arrays. Only arrays passing QC criteria after hybrisiation were subsequently analysed.
Project description:Mammary gland development is fueled by stem cell self-renewal and differentiation. External cues from the microenvironment coupled with internal cues such as post-transcriptional regulation exerted by miRNAs regulate stem cell behavior and stem cell fate. We have identified a miR205 regulatory network required for mammary gland morphogenesis and stem cell maintenance. In the postnatal mammary gland, miR205 is predominantly expressed in the basal/stem cell enriched population. Conditional deletion of miR205 in mammary epithelial cells severely impaired stem cell self-renewal and mammary repopulating potential both in vitro and in vivo. miR205 null glands displayed significant changes in the basal population, basement membrane and stroma. NKD1 and PP2A-B56, which inhibit the Wnt signaling pathway, and AMOT, which causes YAP cytoplasmic retention and inactivation were identified as miR205 downstream effectors. Collectively these findings reveal an essential role of miR205 in mammary gland development.
Project description:Mammary gland ductal morphogenesis depends on the differentiation of mammary stem cells (MaSCs) into basal and luminal lineages. The AP-2γ transcription factor, encoded by Tfap2c, has a central role in mammary gland development but its effect in mammary lineages and specifically MaSCs is largely unknown. Herein, we utilized an inducible, conditional knockout of Tfap2c to elucidate the role of AP-2γ in maintenance and differentiation of MaSCs. Loss of AP-2γ in the basal epithelium profoundly altered the transcriptomes and decreased the number of cells within several clusters of mammary epithelial cells, including adult MaSCs and luminal progenitors. AP-2γ regulated the expression of genes known to be required for mammary development including Cebpb, Nfkbia, and Rspo1. As a result, AP-2γ-deficient mice exhibited repressed mammary gland ductal outgrowth and inhibition of regenerative capacity. The findings demonstrate that AP-2γ can regulate development of mammary gland structures potentially regulating maintenance and differentiation of multipotent MaSCs.
Project description:The Wnt/beta-catenin signalling pathway plays a central role in mammary stem cell homeostasis and in breast cancer. We employed the CD29hiCD24+ cell surface antigens to identify a subpopulation of mammary CSCs from Apc1572T/+, a mouse model for metaplastic breast adenocarcinoma, a subtype of triple-negative breast cancer in man. The MaCSCs are capable of recapitulating tumorigenesis when transplanted at low multiplicities in vivo, and of forming self-renewing organoids in vitro. Expression profiling of the different subpopulations sorted from normal and neoplastic mammary tissues revealed that the normal stem cell compartment is more similar to tumor cells than to their own differentiated progenies. Accordingly, Wnt signaling was found to be activated in the subpopulation encompassing normal mammary stem cells, though to a lesser degree than in the tumor cells. By comparing normal with cancer mouse mammary compartments, we were able to derive a MaCSC-specific signature composed of human orthologous genes able to predict poor survival, relapse and distant metastasis in human breast cancer. Finally, upon intravenous injection, only MaCSCs among the different tumor cell subpopulations are able to form metastatic lesions in a broad spectrum of anatomical sites. Overall, our data indicate that constitutive Wnt signaling activation interferes with mammary stem cell homeostasis leading to metaplasia and basal-like adenocarcinomas.
Project description:The Wnt/beta-catenin signalling pathway plays a central role in mammary stem cell homeostasis and in breast cancer. We employed the CD29hiCD24+ cell surface antigens to identify a subpopulation of mammary CSCs from Apc1572T/+, a mouse model for metaplastic breast adenocarcinoma, a subtype of triple-negative breast cancer in man. The MaCSCs are capable of recapitulating tumorigenesis when transplanted at low multiplicities in vivo, and of forming self-renewing organoids in vitro. Expression profiling of the different subpopulations sorted from normal and neoplastic mammary tissues revealed that the normal stem cell compartment is more similar to tumor cells than to their own differentiated progenies. Accordingly, Wnt signaling was found to be activated in the subpopulation encompassing normal mammary stem cells, though to a lesser degree than in the tumor cells. By comparing normal with cancer mouse mammary compartments, we were able to derive a MaCSC-specific signature composed of human orthologous genes able to predict poor survival, relapse and distant metastasis in human breast cancer. Finally, upon intravenous injection, only MaCSCs among the different tumor cell subpopulations are able to form metastatic lesions in a broad spectrum of anatomical sites. Overall, our data indicate that constitutive Wnt signaling activation interferes with mammary stem cell homeostasis leading to metaplasia and basal-like adenocarcinomas.
Project description:Macrophages are involved in immune defense, organogenesis and tissue homeostasis. They also contribute to the different phases of mammary gland remodeling during development, pregnancy and involution post-lactation. Yet, less is known about the dynamics of mammary gland macrophages in the lactation stage. Here, we describe a macrophage population present during lactation in mice. By multi-parameter flow cytometry and single-cell RNA sequencing we reveal this population as distinct from the two resident macrophage subsets present pregestationally. These lactation-induced macrophages (LiMacs) are predominantly monocyte-derived and expand by proliferation in situ concomitant with nursing. LiMacs develop independently of IL-34 but require CSF-1 signaling and are partly microbiota-dependent. Locally, they reside adjacent to the basal cells of the alveoli and extravasate into the milk. Moreover, we also found several macrophage subsets in human milk, resembling LiMacs. Collectively, these findings reveal the emergence of unique macrophages in the mammary gland and milk during lactation.