Metabolomics,Unknown,Transcriptomics,Genomics,Proteomics

Dataset Information

Mammary development during pregnancy (controlateral control vs. cleared fat pad) to define transdifferentiation factors

ABSTRACT: Tissue from cleared mammary fat pad and sham-operated controlateral control was removed before and at 10, 15,17, and 19 days of pregnancy. Cleared vs. controlateral tissue was hybridized in dye-swap design to in-house cDNA microarry platform. This design aims to identify factors signaling from the epithelial part of the mammary gland to the surrounding fat pad to initiate adipo-epithelial transdifferentiation. We surgically removed the epithelial part of the 4th mammary gland (including the nipple and the rudimentary ductal tree) in three weeks old CD1 mice where the ductal anlage is confined to the proximal part of the mammary fat pad close to the nipple. The controlateral gland was sham-operated as control. This leaves a cleared mammary fat pad in its endogenous environment. The dissected tissues were subjected to whole mount analysis to judge if the removal of epithelial tissue was complete. At the age of 10 to 15 weeks the tissues were harvested before and 10, 15, 17, and 19 days after the start of pregnancy. RNA from cleared fat pads were compared to sham-operated contralateral controls by competitive hybridization on two-channel microarrays. If enough material was available three different pools of RNA (= three biological replicates) were used for hybridization (from d19 material only two replicates were obtained) in a dye-swap configuraiton (one biological replicate of d17 and d19 samples did not provide sufficient amount for a dyw-swap pair).

ORGANISM(S): Mus musculus

SUBMITTER: Andreas Prokesch

PROVIDER: E-GEOD-50447 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

ACCESS DATA

Similar Datasets

Project description:During lactation, mammary epithelial secretory cells secrete huge amounts of milk from their apical side. The major milk proteins, the caseins, are secreted by exocytosis, while milk fat globules are released by budding, enwrapped by the plasma membrane. Due to the number and large size of milk fat globules, the membrane surface needed for their secretion might exceed that of the apical plasma membrane. In order to identify the cellular compartments that may provide membrane during the budding of milk fat globules, a large-scale proteomics analysis of both cytoplasmic lipid droplets and secreted milk fat globules membranes was performed in mouse cells. The differential analysis of the protein profiles of these two organelles strongly suggest that, in addition to the apical plasma membrane, at least the endoplasmic reticulum, the secretory vesicles containing caseins, and potentially the mitochondria contribute to the formation of the milk fat globule membrane. Moreover, the specific analysis of the membrane-associated as well as the raft-associated proteins reinforces this possibility and points to a role for lipid rafts in milk product secretion. The subcellular localization of several major proteins of the cytoplasmic lipid droplets or of the milk fat globule membrane was investigated by immunofluorescence in lactating mammary epithelial cells. Furthermore, the localization of GM1 ganglioside, a known marker of lipid rafts and of free cholesterol, showed a clear association with both cytoplasmic lipid droplets and secreted milk fat globules. Additionally, the presence of some SNARE proteins that may be involved in casein exocytosis and of two Rab GTPases on both cytoplasmic lipid droplets and milk fat globules was demonstrated by immunofluorescence. Altogether, our results provide evidence for a pivotal role of the endoplasmic reticulum as membrane contributor to milk fat globule budding, and suggest that some SNARE proteins may spatio-temporally coordinate the secretion of milk products.

Project description:Mammary gland involution represents one of the most dramatic examples of programmed cell death/apoptosis and tissue regression during development, yet large gaps still exist in the understanding of the mechanisms involved, and the key factors that trigger involution, are not yet identified. With the focus on identifying ânovelâ genes associated with mammary gland regression, we used microarray analysis to examine differentially expressed genes during early mammary gland involution in the mouse. We believe that such analysis may facilitate the identification of genes that report on proliferative changes in the breast, particularly with regards to growth arrest and growth inhibition. We further reasoned that genes that inhibit mammary gland proliferation might have relevance to breast tumorigenesis since cancer is generally associated with a defect in apoptosis and cell growth arrest. Gene expression from day 0 (D0) of involution was compared to day 1 (D1, 24 hr post weaning) to identify genes exhibiting differential expression. A total of 5,826 genes were identified as being differentially expressed. Changes in gene expression were confirmed by quantitative real time PCR analysis of 21 randomly selected genes. Following the selection of a number of highly regulated mouse genes within this cohort, database searches were then employed to identify genes associated with human tumorigenesis. With an ultimate goal being the identification of genes, which under normal physiological conditions, inhibit breast proliferation, and therefore have the potential to impact on the clinical management of breast cancer, we further examined their relevance to human tumorigenesis. Among genes identified as having human homologues, and with previously established links to human tumorigenesis, were several known genes among the top 200 differentially expressed genes including EGF, EGFR, TGFÃ2, PTHLH, IGFBP1, that were down regulated. Upregulated known genes included ANNEXIN A1 and A3, THYMOSIN BETA 10, IGFBP5, LIF, BID, BCL2, JUN, KIT, and CLAUDIN 1. CLAUDIN 1 was the most highly upregulated gene in our dataset. Moreover, we identified a number of genes not previously implicated or not well characterized in human breast cancer including ANGPTL4, SLC34A2, GOS2, STEAP, SOX4, TNFRSF12A and SAA2. The expression levels of these genes in human breast cancer were confirmed in breast cancer cell lines and breast tumor tissues. For some of these genes, expression was consistently down regulated in a small panel of human breast tumor specimens. We believe that these genes now warrant further investigation to determine their relevance to human breast tumorigenesis and their potential utility as therapeutic targets for human breast cancer. This pilot study was used to demonstrate proof of principle that through the analysis of gene expression during mammary gland involution, it may be indeed possible to identify ânovelâ genes relevant to the growth arrest in the mammary gland and relevant to human breast cancer. Experiment Overall Design: Pooled RNA from D0 mice and from D1 mice, (five mice per time point), was compared for differential gene expression by microarray analysis conducted by Paradigm Array Labs (Research Triangle Park, North Carolina, USA). The Affymetrix GeneChip Mouse Genome 430 Plus 2.0 Array (Affymetrix, Santa Clara CA. USA) was used. The array contained 45,100 probe sets (The Affymetrix probe-set identificator) and represented 39,000 transcripts. The Affymetrix Statistical Algorithms, implemented in the Affymetrix Microarray Suite 5.0 software, were used in the expression analysis of GeneChip probe arrays.

Dataset Information

Mammary development during pregnancy (controlateral control vs. cleared fat pad) to define transdifferentiation factors

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure