Project description: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 MECâ??s 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. Human milk sampling throughout lactation cycle and during mastitic infection.
Project description: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 MEC’s 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.
Project description:The mammary gland develops mainly postnatally, when during pregnancy the epithelium grows out into the mammary fat pad and forms a network of epithelial ducts. During pregnancy, these ducts branch and bud to form alveoli. These alveoli produce the milk during lactation. After 7 days of lactation, involution was induced by force weaning the pups. The newly formed epithelium undergoes apoptosis and is removed from the tissue by neighbouring epithelial cells. Tissue remodelling leads to a morphology resembling a gland of a pre-pregnant mouse. Microarray analysis was used to measure mRNA expression of genes during puberty, pregnancy, lactation and involution in a Balb/c mouse strain. Keywords: developmental time course
Project description:The mammary gland develops mainly postnatally, when during pregnancy the epithelium grows out into the mammary fat pad and forms a network of epithelial ducts. During pregnancy, these ducts branch and bud to form alveoli. These alveoli produce the milk during lactation. After 7 days of lactation, involution was induced by force weaning the pups. The newly formed epithelium undergoes apoptosis and is removed from the tissue by neighbouring epithelial cells. Tissue remodelling leads to a morphology resembling a gland of a pre-pregnant mouse. Microarray analysis was used to measure mRNA expression of genes during puberty, pregnancy, lactation and involution in a Balb/c mouse strain. Experiment Overall Design: Total RNA was extracted from the 4th (inguinal) gland after removal of the lymph node. Individual samples represent RNA from one gland of one mouse. Samples were taken in triplicate (i.e. three mice per triplicate) for 18 time points of development.
Project description:Macrophages are involved in immune defense, organogenesis and tissue homeostasis. They also contribute to the different phases of mammary gland remodeling during development, pregnancy and involution post-lactation. Yet, less is known about the dynamics of mammary gland macrophages in the lactation stage. Here, we describe a macrophage population present during lactation in mice. By multi-parameter flow cytometry and single-cell RNA sequencing we reveal this population as distinct from the two resident macrophage subsets present pregestationally. These lactation-induced macrophages (LiMacs) are predominantly monocyte-derived and expand by proliferation in situ concomitant with nursing. LiMacs develop independently of IL-34 but require CSF-1 signaling and are partly microbiota-dependent. Locally, they reside adjacent to the basal cells of the alveoli and extravasate into the milk. Moreover, we also found several macrophage subsets in human milk, resembling LiMacs. Collectively, these findings reveal the emergence of unique macrophages in the mammary gland and milk during lactation.
Project description:Different lactation stages have marked influence on milk yield, milk constituents and nourishment of the neonates. However, the differential gene expression during different lactation stages in Bosindicus has not been investigated so far. In this study, we carried out high-resolution mass spectrometry-based quantitative proteomics of bovine whey at early, mid and late lactation stages of MalnadGidda (Bosindicus) cows. Using TMT-based quantitative proteomics, we compared the bovine whey proteins on progressive lactation stages of Indian breed, MalnadGidda(Bosindicus). LC-MS/MS analysis of whey peptides from early, mid and late lactation stages resulted in the generation of 420,092 MS/MS spectra and 50,800 peptide spectrum matches, which led to the identification of 4,450 peptides corresponding to 725 proteins. Out of which, 440 proteins were differentially expressed (≥1.5-fold). Gene Ontology studies showed that proteins that regulatemilk composition and mammary growth associated proteins are abundantly expressed during peak lactation stages. Whereas, proteins related to pregnancy and mammary involution are expressed high in late and mid lactation stages indicating the physiological changes in the maternal system of bovine during drying period. Detection of progestagen associated endometrial protein; an immune protein seen in the fetomaternal interface and other pregnancy associated proteins at mid lactation suggest a candidate biomarker for the early pregnancy diagnosis. These results are overlapping with the previous findings addressed in milk from exotic breeds. We strongly believe that this preliminary investigation on differential proteome in milk whey over the course of lactation of indigenous cattle could answer many unsolved questions in lactation biology.
Project description:Macrophages are involved in immune defense, organogenesis and tissue homeostasis. They also contribute to the different phases of mammary gland remodeling during development, pregnancy and involution post-lactation. Yet, less is known about the dynamics of mammary gland macrophages in the lactation stage. Here, we describe a macrophage population present during lactation in mice. By multi-parameter flow cytometry and single-cell RNA sequencing we reveal this population as distinct from the two resident macrophage subsets present pregestationally. These lactation-induced macrophages (LiMacs) are predominantly monocyte-derived and expand by proliferation in situ concomitant with nursing. LiMacs develop independently of IL-34 but require CSF-1 signaling and are partly microbiota-dependent. Locally, they reside adjacent to the basal cells of the alveoli and extravasate into the milk. Moreover, we also found several macrophage subsets in human milk, resembling LiMacs. Collectively, these findings reveal the emergence of unique macrophages in the mammary gland and milk during lactation.
Project description:Macrophages are involved in immune defense, organogenesis and tissue homeostasis. They also contribute to the different phases of mammary gland remodeling during development, pregnancy and involution post-lactation. Yet, less is known about the dynamics of mammary gland macrophages in the lactation stage. Here, we describe a macrophage population present during lactation in mice. By multi-parameter flow cytometry and single-cell RNA sequencing we reveal this population as distinct from the two resident macrophage subsets present pregestationally. These lactation-induced macrophages (LiMacs) are predominantly monocyte-derived and expand by proliferation in situ concomitant with nursing. LiMacs develop independently of IL-34 but require CSF-1 signaling and are partly microbiota-dependent. Locally, they reside adjacent to the basal cells of the alveoli and extravasate into the milk. Moreover, we also found several macrophage subsets in human milk, resembling LiMacs. Collectively, these findings reveal the emergence of unique macrophages in the mammary gland and milk during lactation.
Project description:Pregnancy-Induced Non-Coding RNA (PINC) is upregulated in alveolar cells of the mammary gland during pregnancy and persist in alveolar cells that remain in the regressed lobules following involution. Here, we show that in the post-pubertal mouse mammary gland, mPINC expression increases throughout pregnancy and then declines in early lactation, when alveolar cells undergo terminal differentiation. Accordingly, mPINC expression is significantly decreased when HC11 mammary epithelial cells are induced to differentiate and produce milk proteins. This natural reduction in mPINC levels may be necessary for lactation, as overexpression of mPINC in HC11 cells blocks lactogenic differentiation, while knockdown of mPINC enhances differentiation. HC11 mammary epithelial cells, with or without knockdown or over-expression of PINC, and with or without treatment by differentiation-inducing agents, were profiled for gene expression.
Project description:The transition from pregnancy to lactation is a critical event in the survival of the newborn since all the nutrient requirements of the infant are provided by milk. While milk contains numerous components, including proteins, that aid in maintaining the health of the infant, lactose and milk fat represent the critical energy providing elements of milk. Much of the research to date on mammary epithelial differentiation has focused upon expression of milk protein genes, providing a somewhat distorted view of alveolar differentiation and secretory activation. While expression of milk protein genes increases during pregnancy and at secretory activation, the genes whose expression is more tightly regulated at this transition are those that regulate lipid biosynthesis. The sterol regulatory element binding protein (SREBP) family of transcription factors is recognized as regulating fatty acid and cholesterol biosynthesis. We propose that SREBP1 is a critical regulator of secretory activation with regard to lipid biosynthesis, in a manner that responds to diet, and that the serine/threonine protein kinase Akt influences this process, resulting in a highly efficient lipid synthetic organ that is able to support the nutritional needs of the newborn. Experiment Overall Design: Key points are examined in a time series of FVB mouse mammary gland development, secretory activation, lactation and involution. Quadruplicate mice (four biological replicates) at each time point were used for statistical power totalling 40 individual arrays in this study. Mice were as staged pregnant day 1 the day that post coital plug was observed, and similarly, lactation day 1 was the first day after birth. Involution day 2 is a forced weening model, where day 9 lactating dams had their litters removed for two days and then the dams were killed.