Project description:MaSC enriched P4 subpopulation with high/low expression of Dll1, were isolated from mammary gland of Dll1-mCherry mice, and sorted for high/low Dll1 expression based on mCherry red fluroscense. Mammary gland associated macrophages were isolated from Dll1cKO mice (C57/B6 strain) and the wild type littermates. Total RNA samples were prepared from these samples and the transcription profiles were compared between these samples to conclude that Dll1 in MaSC is critical to mediate interaction to macrophageal niche and in turn supports the proper MaSC function.
Project description:The capacity of stem cells to maintain and regenerate organs is critically dependent on the niche, a complex signaling microenvironment that sustains and regulates stem cell activity. Niche function in the mammary gland must integrate local homeostatic activities with hormonally regulated events, such as pregnancy or the onset of puberty. In the human disorder CPHD (combined pituitary hormone deficiency) breast growth defects at puberty are associated with mutations disrupting the transcription factor, GLI2. Here we find that Gli2 functions in mouse mammary stromal cells to shape a niche signaling program that sustains mammary epithelial stem cells. Ablation of Gli2 in stromal cells thus leads to a disorganized mammary gland, associated with collapse of the niche signaling environment, with a five-fold decrease in functional mammary stem cell activity, and with attenuated response to the mammatrophic hormones estrogen and growth hormone. Consistent with a niche defect, aspects of Gli2-deficient mammary gland architecture can be rescued by local supplementation with IGF and WNT protein signals. Our findings thus identify GLI2 as a critical coordinator of local and hormonal influences on the niche signaling program, and suggest that mammary pathogenesis in CPHD patients results from dysfunction of the mammary epithelial stem cell niche. We used microarrays to identify gene expression signatures associated with stromal Gli2 expression
Project description:Bovine mammary stem cells (MaSC) are a source of ductal and lobulo-alveolar tissue during development of mammary gland and its remodeling in repeating lactation cycles. We hypothesize that the number of MaSC, their molecular properties and interactions with their niche may be essential to determine the mammogenic potential in heifers. To verify this hypothesis we compared the number of MaSC and transcriptomic profile in mammary tissue of 2-year-old, non-pregnant dairy (Holstein-Friesian) and beef (Limousin) heifers. For identification and quantification of putative stem/progenitor cells in mammary tissue sections scanning cytometry was used with a new combination of MaSC molecular markers: stem cell antigen-1 (Sca-1) and fibronectin type III domain containing 3B (FNDC3B) protein. Double labeled cells were located mainly in the basal layers of mammary epithelium. Cytometric analysis of Sca-1pos FNDC3Bpos cells revealed significantly higher number in HF (2.94M-BM-10.35%) than in LM (1.72M-BM-10.20%) heifers. More advanced development of mammary tissue in HF heifers was accompanied by higher expression of intramammary hormones, growth factors, cytokines, chemokines and transcription regulators. The model of transcriptomic niche favorable for MaSC was associated with regulation of genes involved in MaSC maintanence, self renewal, proliferation, migration, differentiation, mammary tissue remodeling, angiogenesis, regulation of adipocyte differentiation, lipid metabolism and steroid and insulin signaling. In conclusion the high mammogenic potential in postpubertal dairy heifers is facilitated by a higher number of MaSC and up-regulation of mammary auto-, paracrine factors representing MaSC niche. Keywords: stem/progenitor cells, transcriptomics, mammary gland, dairy and beef heifers Two-condition experiment, LIM vs. HF. Pulled quarters of mammary glands form 10 LIM heifers (test) and 10 HF heifers (reference). Sample 3 and 4 are dye swaps.
Project description:Bovine mammary stem cells (MaSC) are a source of ductal and lobulo-alveolar tissue during development of mammary gland and its remodeling in repeating lactation cycles. We hypothesize that the number of MaSC, their molecular properties and interactions with their niche may be essential to determine the mammogenic potential in heifers. To verify this hypothesis we compared the number of MaSC and transcriptomic profile in mammary tissue of 2-year-old, non-pregnant dairy (Holstein-Friesian) and beef (Limousin) heifers. For identification and quantification of putative stem/progenitor cells in mammary tissue sections scanning cytometry was used with a new combination of MaSC molecular markers: stem cell antigen-1 (Sca-1) and fibronectin type III domain containing 3B (FNDC3B) protein. Double labeled cells were located mainly in the basal layers of mammary epithelium. Cytometric analysis of Sca-1pos FNDC3Bpos cells revealed significantly higher number in HF (2.94±0.35%) than in LM (1.72±0.20%) heifers. More advanced development of mammary tissue in HF heifers was accompanied by higher expression of intramammary hormones, growth factors, cytokines, chemokines and transcription regulators. The model of transcriptomic niche favorable for MaSC was associated with regulation of genes involved in MaSC maintanence, self renewal, proliferation, migration, differentiation, mammary tissue remodeling, angiogenesis, regulation of adipocyte differentiation, lipid metabolism and steroid and insulin signaling. In conclusion the high mammogenic potential in postpubertal dairy heifers is facilitated by a higher number of MaSC and up-regulation of mammary auto-, paracrine factors representing MaSC niche. Keywords: stem/progenitor cells, transcriptomics, mammary gland, dairy and beef heifers
Project description:Calorie restriction (CR) enhances stem cell self-renewal in various tissues, including the mammary gland. The hypothesis propelling this study states that similarly to their intestinal counterparts, mammary epithelial stem cells are insulated from sensing changes in the energy supply and, for that matter, depend on signals from a specific niche. Combined in vivo, in vitro and in silico studies identified macrophages and secreted CSF1 as the energy sensor and paracrine transmitter, respectively, of the CR inducing effect on mammary stem cell self-renewal.
