Project description:Constitutive expression of miR-150 in mammary epithelium causes severe lactation defects. Mammary epithelial cells (MECs) at lactation day 2 were isolated from four homozygous ROSA26-lox-STOP-lox-miR-150 (Stop-150) mice with WAP-driven Cre (WAP-Cre) and compared to MECs from four WAP-Cre control mice. Statistical analysis of the mRNA changes between the two genotypes identified supression of many lipid and cholesterol synthesis genes due to constitutive expression of miR-150.
Project description:Previoulsly miRNA expression profiling of the whole mammary gland across different stages of pregnancy and lactation has been performed in mice. Since mammary gland has both epithelial and stromal compartments, to specifically identify the miRNAs involved in the transition from pregnancy to lactation a process termed as secretory activation, expression profiling of isolated mammary epithelial cells (MECs) from four CD1 mice each at Pregnancy day 14 (P14) and Lactation day 2 (L2) was performed in the current study. Statistical analysis of the miRNA changes between P14 and L2 identified 32 miRNAs to be differentially expressed with a fold change greater than or equal to 2, of which, the majority of them declinied at the onset of lactation.
Project description:2-methoxyestradiol (2ME2) induces mammary gland differentiation through amphiregulin-EGFR mediated signaling: molecular distinctions from the mammary gland of pregnant mice.High levels of 2ME2 are observed in the late stages of pregnancy. We investigated the role of 2ME2 on normal mammary gland development. Large scale gene expression assays were performed using Affymetrix GeneChips in pursuit of detailed molecular basis. (1) Mammary glands of wild type FVB mice administered 75 or 150 mg/kg of 2ME2 (2) Mammary glands of normal FVB/Nj mice (i) at day 16 of pregnancy, (ii) day 2 of lactation (iii) day 30 of post-lactation, and (3) mammary epithelial SCp2 cells after 6, 24 and 48 hours of 10 micromol 2ME2 treatment were examined. In vivo studies revealed that 2ME2 treatment up regulates the expression of amphiregulin. The clue to the role of 2ME2 in differentiation comes from studies in vitro which detected down regulation of inhibitor of differentiation (Id-1) gene and consequent up regulation of amphiregulin. The differentiation of E2 negative SCp2 cells by 2ME2 indicate estradiol independent mechanism. For details, please see our paper in Endocrinology 2006. **NOTE: Migrated from caArray 1.x, identifier='gov.nih.nci.ncicb.caarray:Experiment:1015897590892008:1'
Project description:Previously we have shown significant differences in lactation performance, mammary gland histology and expression profiles of mammary transcriptome during peak-lactation (lactation day 9; L9) between the ordinary CBA/CaH (CBA) and the superior QSi5 strains of mice. In the present study, we compared mammary gland histology between CBA and QSi5 at mid-pregnancy (pregnancy day 12; P12). We assessed lactation performance during the first 8 days of lactation of the 13th - 14th generation of the Advanced Intercross Line (AIL) (CBA X QSi5) mice. We utilized an integrative approach to analyzing mammary microarray expression profiles of CBA and QSi5 at P12 and CBA, AIL and QSi5 at L9.
Project description:Previoulsly expression profiling of the whole mammary gland across different stages of pregnancy and lactation has been performed on different strains of mice. Since mammary gland has both epithelial and stromal compartments, to specifically identify the genes involved in the transition from pregnancy to lactation a process termed as secretory activation, expression profiling of isolated mammary epithelial cells (MECs) from four CD1 mice each at Pregnancy day 14 (P14) and Lactation day 2 (L2) was performed in the current study. Statistical analysis of the mRNA changes between P14 and L2 identified 5,499 unique genes as being differentially expressed (5% FDR), of which, 2,902 genes and 2,604 genes were higher in P14 or L2 stages, respectively.
Project description:The mammary gland undergoes extensive remodeling between the begin- ning of pregnancy and lactation; this involves cellular processes including cell proliferation, differentiation, and apoptosis, all of which are under the control of numerous regulators. To unravel the role played by miRNA, we describe here 47 new ovine miRNA cloned from mammary gland in early pregnancy displaying strong similari- ties with those already identified in the cow, human, or mouse. A microarray study of miRNA variations in the adult ovine mammary gland during pregnancy and lactation showed that 100 miRNA are regulated according to three principal patterns of expression: a de- crease in early pregnancy, a peak at midpregnancy, or an increase throughout late pregnancy and lactation. One miRNA displaying each pattern (miR-21, miR-205, and miR-200b) was analyzed by qRT- PCR. Variations in expression were confirmed for all three miRNA. Using in situ hybridization, we detected both miR-21 and miR-200 in luminal mammary epithelial cells when expressed, whereas miR-205 was expressed in basal cells during the first half of pregnancy and then in luminal cells during the second half. We therefore conclude that miR-21 is strongly expressed in the luminal cells of the normal mammary gland during early pregnancy when extensive cell prolif- eration occurs. In addition, we show that miR-205 and miR-200 are coexpressed in luminal cells, but only during the second half of pregnancy. These two miRNA may cooperate to maintain epithelial status by repressing an EMT-like program, to achieve and preserve the secretory phenotype of mammary epithelial cells. 5 samples for sheep and 5 samples for mouse
Project description:To identify gene expression changes associated with overexpression of miR-105 or MYC in MCF10A non-cancerous human mammary epithelial cells, we analyzed RNA isolated from engineered MCF10A cell lines that stably express empty vector, GFP, miR-105, or MYC by RNA-seq. Gene expression in cells overexpressing miR-105 or MYC was compared to cells expressing the empty vector or GFP, both of which served as controls in this experiment.
Project description:The mammary gland undergoes extensive remodeling between the begin- ning of pregnancy and lactation; this involves cellular processes including cell proliferation, differentiation, and apoptosis, all of which are under the control of numerous regulators. To unravel the role played by miRNA, we describe here 47 new ovine miRNA cloned from mammary gland in early pregnancy displaying strong similari- ties with those already identified in the cow, human, or mouse. A microarray study of miRNA variations in the adult ovine mammary gland during pregnancy and lactation showed that 100 miRNA are regulated according to three principal patterns of expression: a de- crease in early pregnancy, a peak at midpregnancy, or an increase throughout late pregnancy and lactation. One miRNA displaying each pattern (miR-21, miR-205, and miR-200b) was analyzed by qRT- PCR. Variations in expression were confirmed for all three miRNA. Using in situ hybridization, we detected both miR-21 and miR-200 in luminal mammary epithelial cells when expressed, whereas miR-205 was expressed in basal cells during the first half of pregnancy and then in luminal cells during the second half. We therefore conclude that miR-21 is strongly expressed in the luminal cells of the normal mammary gland during early pregnancy when extensive cell prolif- eration occurs. In addition, we show that miR-205 and miR-200 are coexpressed in luminal cells, but only during the second half of pregnancy. These two miRNA may cooperate to maintain epithelial status by repressing an EMT-like program, to achieve and preserve the secretory phenotype of mammary epithelial cells.
Project description:We profiled differential gene expression in vivo between pregnant day 14 (secretory differentiation) and lactation day 4 (established secretory activation) using isolated mouse mammary epithelial cells depleted of the mammary adipocytes. Liver-X-Receptors are ligand-dependent transcription factors activated by cholesterol metabolites. These receptors induce a suite of target genes required for de novo synthesis of triglycerides and cholesterol transport in many tissues. Two different isoforms -LXRα and LXRβ- have been well characterized in liver, adipocytes, macrophages and intestinal epithelium among others, but their contribution to cholesterol and fatty acid efflux in the lactating mammary gland is poorly understood. We hypothesize that LXR regulates lipogenesis during milk fat production in lactation. Global mRNA analysis of mouse mammary epithelial cells (MECs) revealed multiple LXR/RXR targets are upregulated sharply at the onset of lactation compared to mid-pregnancy. LXRα is the primary isoform and its protein levels increase throughout lactation in MECs. The LXR agonist GW3965 markedly induced several genes involved in cholesterol transport and lipogenesis and enhanced cytoplasmic lipid droplet accumulation in the HC11 MEC cell line. Importantly, in vivo pharmacological activation of LXR increased the milk cholesterol percentage and induced Srebp1c and Abca7 expression in MECs. Cumulatively, our findings identify LXRα as an important regulator of cholesterol incorporation into the milk through key nodes of de novo lipogenesis, suggesting a potential therapeutic target in women with difficulty initiating lactation.
Project description:The mammary gland of the lactating mouse synthesizes and secretes milk lipid equivalent to its entire body weight in a single 20 day lactation cycle, making it one of the most active lipid synthetic organs known. To test the hypothesis that multiple metabolic control points and potential regulatory mechanisms are involved in activating lipid and lactose synthesis at the onset of lactation we compared the mammary transcriptome of 130 genes involved in glucose metabolism between late pregnancy and early lactation and in response to dietary fat. We utilized data obtained from microarray analysis of mammary glands from quadruplicate FVB mice at pregnancy day 17, and lactation day 2. Diets containing 8% or 40% lipid were fed from lactation days 5 to 10 and mammary glands and livers of triplicate FVB mice prepared for microarray analysis. We also compared the metabolome obtained from magnetic resonance spectroscopy of flash frozen glands of the mammary gland at day 17 of pregnancy with that at day 2 of lactation. The results provide a global picture of the multiple metabolic strategies utilized to turn a quiescent organ into an incredibly efficient machine for massive but balanced lipid and lactose synthesis and implicate the transcription factor SREBP-1c in regulation of part of the pathway. Keywords: Timecourse and dose response to dietary fat