Project description:Human breast milk contains a diverse community of bacteria but factors that produce variation in the breast milk microbiome are largely unknown. We evaluated if 1) maternal factors including breastfeeding practices modified the diversity and abundance of bacterial communities in breast milk and 2) if subclinical mastitis (SCM), an asymptomatic inflammatory condition occurring during lactation, induced a distinctive microbiota signature.
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: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:Purpose:To present the miRNA expression profiles in giant panda milk exosomes across five lactation stages (0, 3, 7, 15 and 30 days after birth), aiming to provide new information for investigations into the physiological functions of the giant panda milk Methods: Three females were sampled in all, and each individual were sampled over multiple lactations, including 0, 3, 7, 15 and 30 days after delivery. Breast milk samples (5-10 ml) were collected from each stages. Total RNA isolated from individuals in five lactation stages (0, 7, 15 and 30 days after delivery) were pooled in equal quantities for each stage Results: Here, we illustrated the species and expression characteristics of exosome-loaded miRNAs existing in giant panda breast milk during distinct lactation periods, and highlighted the enrichment of immune- and development-related endogenous miRNAs in colostral and mature giant panda milk, which are stable even in certain hash conditions, like low pH and high concentration of RNAase, by the protection of extracellular vesicles.These findings indicate that breast milk may allow dietary intake of maternal miRNAs by infants for the regulation of postnatal development. We also demonstrated that the exogenous plant miRNA from the primary food source of giant panda (bamboo) were detected in the exosomes of giant panda breast milk, which were predicted to be of regulatory role in basic cell metabolism and neuron development. This result suggested that the dietary plant miRNAs were able to be absorbed by host cell and then secreted to body fluids as potential cross-kingdom regulators. Conclusions: Exosomal miRNAs in the giant panda breast milk may be the crucial maternal regulators for the development of intrinsic ‘slink’ newborn cubs.
Project description:Despite the documented benefits of breastfeeding and major governmental advocacy efforts, a paucity of data exists regarding the transfer of most drugs into breast milk. Passive diffusion governs the extent of accumulation for most drugs and the exposure risk can therefore be predicted using mathematical models. However, examples of xenobiotic accumulation into breast milk well above that predicted by passive diffusion have been documented and attributed to drug transport. A thorough evaluation of the expression of xenobiotic transporters in mammary epithelial cells (MECs), the cells that form the anatomical barrier between maternal serum and breastmilk, during lactation is necessary to determine the drugs for which an active transport mechanism governs transfer into breast milk and to improve predictive models. We used microarrays to evaluate gene expression in human mammary epithelial cells and identified xenobiotic trasnporter genes that were upregulated during lactation.
Project description:Breast milk is the primary source of nutrition for newborns, and rich in immunological components. microRNAs (miRNAs), a well-defined group of non-coding small RNAs, are present in various body fluids (such as breast milk), which are selectively packaged inside the exosomes, a type of membrane vesicles, secreted by most cell types. These exosomal miRNAs could be actively delivered into recipient cells, and regulate target gene expression and recipient cell function. We present the lactation-related miRNA expression profiles in porcine milk exosomes across entire lactation period in pig industry (newborn to 28 days after birth) using deep sequencing technology. We found that the immune-related miRNAs are presented and enriched in breast milk exosomes, and generally resistant to relatively harsh conditions. Notably, these exosomal miRNAs exhibited the higher abundances in the colostrum (newborn to 3 days after birth) than that in the mature milk (7 to 28 days after birth), as well as in the serum of colostrum-feeding piglets compared with the only mature milk-feeding piglets. These immune-related miRNAs-loaded exosomes in breast milk may be transferred into the infant body via the digestive tract. These observations are prelude to the in-depth investigations of the essential roles of the breast milk in the development of the infant’s immune system.
Project description:Human milk fat globules, by enveloping cell contents during their secretion into milk, are a rich source of mammary cell RNA. Here, we pair this non-invasive mRNA source with RNA sequencing technology to probe the milk fat layer transcriptome during three stages of lactation: colostral, transitional, and mature milk production. We find that transcriptional profiles cluster not by postpartum day, but by milk Na:K ratio, indicating that women sampled during the same postpartum time frame could be at markedly different stages of gene expression. Each stage of lactation is characterized by a dynamic range (105-fold) in transcript abundances not previously observed with microarray technology. We discovered that transcripts for isoferritins and cathepsins are strikingly abundant during colostrum production, highlighting the potential importance of these proteins for neonatal health. Two transcripts, encoding M-NM-2-casein (CSN2) and a-lactalbumin (LALBA), make up 45% of the total pool of mRNA in mature lactation. Genes significantly expressed across all stages of lactation are associated with making, modifying, transporting, and packaging milk proteins. Stage-specific transcripts are associated with immune defense during the colostral stage, up-regulation of the machinery needed for milk protein synthesis during the transitional stage, and the production of lipids during mature lactation. We observed strong modulation of key genes involved in lactose synthesis and insulin signaling. In particular, PTPRF may serve as a biomarker linking insulin resistance with insufficient milk supply. This study provides the methodology and reference data set to enable future targeted research on the physiological contributors to sub-optimal lactation in humans. Milk fat mRNA profiles were generated from Day 2 and mature milk samples obtained from lactating mothers
Project description:High throughput sequencing of miRNAs collected from tammar milk at different time points of lactation showed high levels of miRNA secreted in milk and allowed the identification of differentially expressed milk miRNAs during the lactation cycle as putative markers of mammary gland activity and functional candidate signals to assist growth and timed development of the young. Comparative analysis of miRNA distribution in milk and blood serum suggests that milk miRNAs are primarily expressed from mammary gland rather than transferred from maternal circulating blood, likely through a new putative exosomal secretory pathway.
Project description:Breast cancer risk is influenced by parity in an age-dependant manner, however human tissue remodelling induced by pregnancy and lactation is not well understood. In most cases, it is difficult to acquire human breast tissue during these key stages of development. Here, we present an approach to overcome this using single-cell RNA sequencing to examine viable primary mammary epithelial cells isolated from human milk (n=4) compared to resting, non-lactating human breast tissue (n=4). Overall, we examined 54,323 viable high-quality cells from mixed age and parous individuals consisting of 29,078 lactation derived mammary cells (LMCs) and 25,245 non-lactation derived mammary cells (NMCs). We identified all documented mammary subpopulations within our breast tissue samples and found that milk contains distinct secretory luminal cells together with myeloid and lymphocytic hematopoietic lineage cells. Comparing the luminal transcriptional profiles of cells isolated from the resting and lactating state identified differences in mammary cell function and metabolism between these maturation states. In future this data may be used to provide an insight into how parity influences human luminal cell metabolism and breast cancer risk.