The molecular processes underlying human milk production and the effects of mastitic infection are largely unknown because of limitations in obtaining tissue samples. Determination of gene expression in normal lactating women would be a significant step towards understanding why some women display poor lactation outcomes. Here we demonstrate the utility of RNA obtained directly from human milk cells to detect mammary epithelial cell (MEC)-specific gene expression. Milk cell RNA was collected from 5 time points (24 hours pre-partum during the colostrum period, mid lactation, two involution, and during a bout of mastitis) in addition to an involution series comprising three time points. Gene expression profiles were determined by use of human Affymetrix arrays. Milk cells collected during milk production showed that the most highly expressed genes were involved in milk synthesis (eg. CEL, OLAH, FOLR1, BTN1A1, ARG2), while milk cells collected during involution showed a significant down regulation of milk synthesis genes and activation of involution associated genes (eg. STAT3, NF-kB, IRF5, IRF7). Milk cells collected during mastitic infection revealed regulation of a unique set of genes specific to this disease state, whilst maintaining regulation of milk synthesis genes. Use of conventional epithelial cell markers was used to determine the population of MECs within each sample. This paper is the first to describe the milk cell transcriptome across the human lactation cycle and during mastitic infection, providing valuable insight into gene expression of the human mammary gland.
Analysis of human breast milk cells: gene expression profiles during pregnancy, lactation, involution, and mastitic infection.
Specimen part
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ChIP-seq analysis reveals distinct H3K27me3 profiles that correlate with transcriptional activity.
Specimen part
View SamplesTranscriptional control is dependent on a vast network of epigenetic modifications. One epigenetic mark of particular interest is tri-methylation of lysine 27 on histone H3 (H3K27me3), which is catalyzed and maintained by the Polycomb Repressor Complex (PRC2). Although this histone mark is studied widely, the precise relationship between its local pattern of enrichment and regulation of gene expression is currently unclear. We have used ChIP-seq to generate genome wide maps of H3K27me3 enrichment, and have identified three enrichment profiles with distinct regulatory consequences. First, a broad domain of H3K27me3 enrichment across the body of genes corresponds to the canonical view of H3K27me3 as inhibitory to transcription. Second, a peak of enrichment around the transcription start site is commonly associated with bivalent genes, where H3K4me3 also marks the TSS. Finally and most surprisingly, we identified an enrichment profile with a peak in the promoter of genes that is associated with active transcription. Genes with each of these three profiles were found in different proportions in each of the cell types studied. The data analysis techniques developed here will be useful for the identification of common enrichment profiles for other histone modifications that have important consequences for transcriptional regulation.
ChIP-seq analysis reveals distinct H3K27me3 profiles that correlate with transcriptional activity.
Specimen part
View SamplesAblation of tetraspanin protein TSPAN12 from human MDA-MB-231 cells significantly decreased primary tumor xenograft growth, while increasing tumor apoptosis. Furthermore, TSPAN12 removal markedly enhanced tumor-endothelial interactions and increased metastasis to mouse lungs. TSPAN12 removal from human MDA-MB-231 cells also caused diminished association between FZD4 (a key canonical Wnt pathway receptor) and its co-receptor LRP5. The result likely explains substantially enhanced proteosomal degradation of -catenin, a key effecter of canonical Wnt signalling. Consistent with disrupted canonical Wnt signaling, TSPAN12 ablation altered expression of LRP5, Naked 1 and 2, DVL2, DVL3, Axin 1 and GSK3 proteins. TSPAN12 ablation also altered expression of several genes regulated by -catenin (e.g. CCNA1, CCNE2, WISP1, ID4, SFN, ME1) that may help to explain altered tumor growth and metastasis. In conclusion, these results provide the first evidence for TSPAN12 playing a role in supporting primary tumor growth and suppressing metastasis. TSPAN12 appears to function by stabilizing FZD4-LRP5 association, in support of canonical Wnt-pathway signaling, leading to enhanced -catenin expression and function.
Tetraspanin TSPAN12 regulates tumor growth and metastasis and inhibits β-catenin degradation.
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View SamplesEWI-2 (IgSF8) plays a novel, bifunctional role in melanoma cells. EWI-2 inhibits migration, metastasis, EMT-like changes, and CD271-dependent invasion in multiple melanoma cell lines. On the other hand, EWI-2 supports melanoma cell proliferation, survival, and xenograft growth. Consistent with these results, EWI-2 levels were elevated in human malignant melanoma, but not in metastatic melanoma samples. Altered melanoma cell functions, caused by EWI-2 ablation, are almost entirely dependent on enhanced TRF-1 signaling, and also require contributions from tetraspanin proteins CD9 and CD81. In melanoma cells lacking EWI-2, tetraspanins CD9 and CD81 enhance TRF-1 signaling by facilitating TR-2TR-1 receptor complex formation. When EWI-2 is present, CD9 and CD81 are diverted into EWI-2 complexes, and thus TRF-1 signaling is inhibited.
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Specimen part
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Epigenetic regulator Smchd1 functions as a tumor suppressor.
Specimen part
View SamplesSmchd1 appears to act as a tumour suppressor in the transformed fibroblast model. We find gene expression differences are most pronounced in the transformed MEFs. We always detect a small number of clustered genes and imprinted genes as differentially expressed, along with others involved in tumorigenesis.
Epigenetic regulator Smchd1 functions as a tumor suppressor.
Specimen part
View SamplesTissue resident memory (Trm) represent a newly described memory T cell population. We have previously characterized a population of Trm that persists within the brain following acute virus infection. Although capable of providing marked protection against a subsequent local challenge, brain Trm do not undergo recall expansion following dissociation from the tissue. Furthermore, these Trm do not depend on the same survival factors as the circulating memory T cell pool as assessed either in vivo or in vitro. To gain greater insight into this population of cells we compared the gene-expression profiles of Trm isolated from the brain to circulating memory T cells isolated from the spleen following an acute virus infection. Trm displayed altered expression of genes involved in chemotaxis, expressed a distinct set of transcription factors and overexpressed several inhibitory receptors. Cumulatively, these data indicates that Trm are a distinct memory T cell population disconnected from the circulating memory T cell pool and displaying a unique molecular signature which likely results in optimal survival and function within their local environment.
The molecular signature of tissue resident memory CD8 T cells isolated from the brain.
Specimen part
View SamplesMYST4 (QKF/KAT6B/MORF) is an important regulator of brain development and function through its regulation of gene expression. Genetic targets of MYST4 are currently unknown. We have therefore carried out microarrays comparing gene expression in wild type and Qkf mouse tissues, namely the dorsal cortex and E12.5 dorsal telencephalon, to elucidate genetic targets of MYST4.
No associated publication
Sex, Age, Specimen part
View SamplesOmental adipose tissue explants were cultured for 24h in serum-free medium in the presence of vehicle (control medium) or macrophage (LPS) and T-cell (anti-CD3/28) stimulants (active medium). SGBS human preadipocytes were differentiated into adipocytes and then exposed to 25% v/v control or active medium.
No associated publication
Specimen part, Treatment, Time
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