Project description:Mammary gland branching morphogenesis is thought to relie on the mobilization of the membrane-anchored matrix metalloproteinase, Mmp14/MT1-MMP, to drive mammary epithelial invasion by remodeling the extracellular matrix and triggering associated signaling cascades. However, the roles that this proteinase plays during postnatal mammary gland development in vivo remain undefined. A mammary gland branching program that occurs during the first 4 weeks of postnatal mouse development, in tandem with recently developed Mmp14-floxed mice and MMTV-Cre transgenics that express Cre recombinase throughout the mammary epithelial cell compartment, were used to characterize the impact of deleting epithelial cell Mmp14 on mammary gland morphogenesis. Transcriptome profiling of mammary epithelial cells was used to investigate the functional roles of MT1-MMP in the postnatal mammary epithelial cell compartment in an unbiased fashion
Project description:We investigated an uncharacterized lncRNA, BC030870, that displays an epithelial cell-restricted expression, is downregulated by TGF-β in mammary gland cells, and controls —among others— Cdkn1a (p21WAF1/Cip1) gene expression at both transcriptional and post-transcriptional levels. BC030870 encodes a functionally active microptide (EPRp) that interacts with proteins belonging to apical junctional complexes. We hypothesized that: 1. BC030870 operates at multiple levels to orchestrate gene networks able to control cell fate, proliferation, and adhesion/migration in epithelial mammary gland cells and 2. the reduced expression of BC030870 in a group of breast cancer cells plays a role in tumor growth and invasiveness. Thus, we wanted to define the transcriptomic changes induced by BC030870 over-expression and to verify the contribution of the EPRp to gene expression changes.
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: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:Mammary gland branching morphogenesis is thought to relie on the mobilization of the membrane-anchored matrix metalloproteinase, Mmp14/MT1-MMP, to drive mammary epithelial invasion by remodeling the extracellular matrix and triggering associated signaling cascades. However, the roles that this proteinase plays during postnatal mammary gland development in vivo remain undefined. A mammary gland branching program that occurs during the first 4 weeks of postnatal mouse development, in tandem with recently developed Mmp14-floxed mice and MMTV-Cre transgenics that express Cre recombinase throughout the mammary epithelial cell compartment, were used to characterize the impact of deleting epithelial cell Mmp14 on mammary gland morphogenesis. Transcriptome profiling of mammary epithelial cells was used to investigate the effects of MMTV-Cre expression on the postnatal mammary epithelial cell compartment in an unbiased fashion
Project description:The Wnt/β-catenin signaling pathway is crucial for the development of variety of organs including the mammary gland. However, the precise role of Wnt/β-catenin signaling during embryonic mammary gland morphogenesis is still poorly understood. Here, we used an epithelial gain-of-function β-catenin mouse model to study the role of Wnt/β-catenin signaling in embryonic mammary gland development and profiled the transcriptomes of E13.5 and E16.5 control and mutant mammary epithelia.
Project description:Transcriptional profiling of mammary gland tumors from transgenic mice overexpressing the p110 or p75 isoform of CUX1. RNA was extracted from epithelial cells isolated using Laser-Capture Microdissection (LCM)