Project description:During gestation, alveolar cells are derived from luminal progenitors in the mammary gland. However, the mechanism underlying luminal progenitor commitment to alveolar cells remains largely unknown. By using five genetically modified mouse lines and single cell RNA sequencing, we identified a Kindlin-2 - Stat3 - Dll1 signaling cascade in myoepithelial cells which controls the inactivation of Notch signaling in luminal cells that consequently drives luminal progenitor commitment to alveolar cells. We found that loss of Kindlin-2 in myoepithelial cells impairs mammary morphogenesis and alveologenesis, and lactation. Single-cell profiling reveals that Kindlin-2 loss significantly decreases the proportion of alveolar cells.
Project description:Analysis of protein tyrosine phosphatase 1B (PTP1B) deficient mammary glands from nulliparous mice at estrous and pregnancy day 3, 7, 10 and 15. We used a genetically ablated PTP1B mouse model to gain a deeper knowledge of the role PTP1B plays in mammary gland development and to define the mechanism regulated by this phosphatase. Results provide insight into the role of PTP1B in mammary gland development and differentiation.
Project description:Analysis of protein tyrosine phosphatase 1B (PTP1B) deficient mammary glands from nulliparous mice at estrous and pregnancy day 3, 7, 10 and 15. We used a genetically ablated PTP1B mouse model to gain a deeper knowledge of the role PTP1B plays in mammary gland development and to define the mechanism regulated by this phosphatase. Results provide insight into the role of PTP1B in mammary gland development and differentiation. Mouse mammary glands were isolated from PTP1B -/- and PTP1B +/+ nulliparous mice at estrous and pregnancy day 3, 7, 10 and 15 for RNA extraction and hybridization on Affymetrix microarrays.
Project description:This submission contains the mass spectrometry files for the manuscript by Aurelie Lacouture et al. that describes the quantitative proteomics analysis of mouse mammary gland epithelial organoids proteome. Experiments were performed from mammary glands organoids derived from mouse and the MS files were acquired on Orbitrap Fusion mass spectrometer. For questions, please contact Etienne Audet-Walsh (Etienne.Audet-Walsh@crchudequebec.ulaval.ca).
Project description:R-spondin1 (Rspo1) is a member of a secreted protein family which has pleiotropic functions in development and stem cell growth. Rspo1 knock-out mice are sex-reversed, but some remain sub-fertile, so, they are unable to nurse their pups. A lack of Rspo1 expression in mammary epithelial cells results in an absence of duct side-branching development and defective alveolar formation. In this study we propose to characterize the molecular functions involved to mammary gland phenotype due to Rspo1 knock out. By transcriptional profiling, we have identified gene misregulated in mammary gland of Rspo1 knock-out mice during pregnancy. A stronger expression of genes characterising mesenchymal tissue was observed in the absence of alterations to the structure of mammary epithelial tissue. Mammary epithelial cell characterization, by immunohistochemistry approach, revealed a persistence of virgin markers which sign a delay in their differentiation. Moreover serial transplantation experiments show that Rspo1 is associated with a regenerative potential of mammary epithelial cell control. Our data have also highlighted that in mammary gland during pregnancy the expression of Rspo1’s partners, Lgr4 and RNF43, are negatively regulated and Tgf-β signaling is modified in the absence of Rspo1. Taken together, our results show an abrupt halt in mammary development at mid-pregnancy due to loss of further differentiated function.
Project description:The main goal of this experiment was to contrast the gene expression of mammary gland tissues at three different tumoral stages : M/D-driven mammary gland small tumors vs mammary gland tissues that have been exposed to M/D but they did not develop a tumor (hyperplastic mammary gland) vs mammary gland tissues that were NOT expossed to M/D (normal mammary gland). Expression profile of 18 mice mammary gland tissues at 3 differents neoplastic stages before and after M/D expossure