Genomic characterization of normal and aberrant human milk production [bulkRNA-seq]
Ontology highlight
ABSTRACT: Breastfeeding is vital for reducing morbidity and mortality, yet exclusive breastfeeding rates are low, with insufficient milk supply being a major weaning factor whose molecular causes remain largely unknown. In this study, we collected fresh milk samples from 30 lactating individuals, classified as low, normal, or high milk producers at multiple postpartum stages, and conducted extensive genomic and microbiome analysis. Using bulk RNA sequencing on human milk fat globules (MFG), milk cells, and breast tissue, we found that MFG-derived RNA closely resembles RNA from milk luminal cells. Furthermore, bulk and single-cell RNA-seq revealed changes in the transcriptome and cellular content linked to milk production. We identified specific genes and cell-type proportions differing in low and high milk production. Infant microbiome diversity was affected by feeding type, but not by maternal milk supply. This study provides a comprehensive human milk transcriptomic catalog, identifies genes associated with milk production, and highlights MFG as a useful biomarker for milk transcriptome analysis.
Project description:Breastfeeding is vital for reducing morbidity and mortality, yet exclusive breastfeeding rates are low, with insufficient milk supply being a major weaning factor whose molecular causes remain largely unknown. In this study, we collected fresh milk samples from 30 lactating individuals, classified as low, normal, or high milk producers at multiple postpartum stages, and conducted extensive genomic and microbiome analysis. Using bulk RNA sequencing on human milk fat globules (MFG), milk cells, and breast tissue, we found that MFG-derived RNA closely resembles RNA from milk luminal cells. Furthermore, bulk and single-cell RNA-seq revealed changes in the transcriptome and cellular content linked to milk production. We identified specific genes and cell-type proportions differing in low and high milk production. Infant microbiome diversity was affected by feeding type, but not by maternal milk supply. This study provides a comprehensive human milk transcriptomic catalog, identifies genes associated with milk production, and highlights MFG as a useful biomarker for milk transcriptome analysis.
Project description:We assessed the effects of supplementing milk fat globules (MFG) on the growth and development of the skeleton in rats fed a Western unbalanced diet (UBD). The UBD is high in sugar and fat, low in protein, fiber, and micronutrients, and negatively impacts health. The MFG—a complex structure secreted in milk—has a unique proteome and lipidome, and differs significantly from isolated dietary ingredients. Rats consuming the UBD exhibited growth retardation and disrupted bone structural and mechanical parameters; these were improved by supplementation with small MFG. The addition of small MFG increased the efficiency of protein utilization for growth, and improved trabecular and cortical bone parameters. Furthermore, consumption of UBD led to a decreased concentration of saturated fatty acids and increased levels of polyunsaturated fatty acids (PUFA), particularly omega-6 PUFA, in the serum, liver, and adipose tissue. The addition of small MFG restored PUFA concentration and the ratio of omega-6 to omega-3 PUFA in bone marrow and adipose tissue. Finally, large but not small MFG supplementation affected the cecal microbiome in rats. Overall, our results suggest that natural structure MFG supplementation can improve metabolism and bone development in rats fed an UBD, with the effects depending on MFG size, whereas the detrimental effects of an UBD on the microbiome were not mitigated by MFG supplementation.
Project description:We have utilized the RNA isolated from breast milk fat globule (MFG) from lactating women from 6h to 42 days following delivery using the HumanHT-12 v4 Expression BeadChip (Illumina, Inc) to determine the temporal coordination of changes in gene expression in milk substrate synthesis processes. Of the 47,323 gene transcripts on the array, 16,623 transcripts were expressed. Major milk protein genes were among the most highly expressed and induced along with those involved in the metabolic and biosynthetic processes of carbohydrate and lipid. Milk fat synthesis mirrors expression of genes involved in fat synthesis, lipolysis and transport. In the lactose synthesis pathway, expression of α-lactalbumin mRNA was high already in the early milk and did not change. Lactose synthesis paralleled the induction of gene expression of proteins involved in UDP-galactose synthesis and transport. Serial milk samples were collected 6h following delivery, q12 h for the first 4 days and then weekly for 6 wks from 7 healthy, lean, exclusively breastfeeding women [7 x 15 = 105 samples]. RNA was isolated from the milk fat globules and utilized for microarray analyses.
Project description:Mammary gland (MG) de novo lipogenesis contributes significantly to milk fat in animals but little is known in humans. We hypothesized that de novo lipogenesis, as reflected by incorporation of 13C carbons from [U-13C]glucose into fatty acids (FAs) and glycerol in triglycerides (TG), will be greater: a. in milk than plasma TG, b. during a high carbohydrate (H-CHO) diet than high fat (H-FAT) diet and c. during feeding than fasting. Healthy lactating women were studied on two isocaloric, isonitrogenous diets. On one occasion subjects received diets containing H-FAT or H-CHO diet for 1 week. Incorporation of 13C from infused [U-13C]glucose into FAs and glycerol was measured using GC/MS methodology and gene expression using RNA isolated from breast milk fat globule (MFG). Incorporation of 13C2 into milk FAs, increased with increased chain length of the FAs from C2:0 to C12:0 but progressively declined in C14:0 and C16:0 and was not detected in FAs >C16. During feeding, regardless of diets, enrichment of 13C2 in milk FA and 13C3 in milk glycerol were ~3 and ~7 fold higher compared to plasma FA and glycerol, respectively. Following an overnight fast during H-CHO and H-FAT diets study periods, 25% and 6%, respectively, of medium chain FAs (MCFAs, C6-C12) were derived from glucose but increased to 75% and 25% with feeding. The expression of genes involved in FA or glycerol synthesis pathways was unchanged regardless of diet or fast-fed conditions. Conclusions: The human MG is capable of de novo lipogenesis, of primarily MCFAs and glycerol, which is influenced by the macro-nutrient composition of the maternal diet. On day 7 of consumption of each of the two diets milk samples collected from 7 healthy, lean, exclusively breastfeeding women following an overnight fast and feeding conditions [7 x 2 x 2 = 28 samples] were processed for isotope enrichments and RNA isolation from the milk fat globules. The total RNA was utilized for microarray analyses.
Project description:The aim of the study was to investigate differences in the gene expression profiles of selected tissues in two most popular goat’s breeds in Poland: Polish White Improved (PWI) and Polish Fawn Improved (PFI). Three different types of tissue samples were selected: somatic cells isolated from goats’ milk (MSC), milk fat globules (MFG) and peripheral nuclear blood cells (PBNC) Since there were no earlier genetic studies focused on genetic differences between these two goat breeds we decided to evaluate hypothetical genomic differences assuming that such a differences should be the consequence of genetic differences. We created the hypothesis that if genomic differences exist they should be revealed in hierarchical clustering of transcriptomic profiles of selected tissues. Should the genomic differences exist the clusters obtained are grouping goat breeds and not goat’s tissues. The results of hierarchical clustering however show something completely different. The clusters are grouping goat tissues (milk fat globules, milk somatic cells, peripheral blood nuclear cells) without any relation with goat breed. So the analytical tool does not recognize the goat breed as a driver of transcriptomic difference. Moreover, we were not able to find significantly regulated genes between two breeds
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: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 β-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.
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:The benefits of breastfeeding infants are well characterized, including those on the immune system. However, determining the mechanism by which human breast milk (HBM) elicits effects on immune response requires investigation in an appropriate animal model. In the current study we used neonatal piglets and compared their gut microbiome using mass spectrometry based metaproteomics
Project description:Mastitis is an inflammation of the mammary gland (MG), usually due to bacterial infection. Although considerable attention has been paid to this economically important disease, the early stages of the host response remain poorly defined. In particular, it is unclear how mammary epithelial cells (MEC), a first barrier against pathogens, respond to infection. Indeed, it is difficult to differentiate between the contributions of MEC and infiltrating immune cells to gene expression profiles of mammary tissue during mastitis. The current investigation examines the response of MEC at the early stage of infection using a non invasive RNA sampling method taking advantage of the presence of cytoplasmic crescents contained in milk fat globules. We have recently shown that, in goats, Milk Fat Globules (MFG) provide a unique source of RNA to study the in vivo regulation of gene expression in MEC. This non invasive RNA sampling method was used during the time course of an experimental intra mammary infection (IMI) with S. aureus. Experiments were performed using ovine microarrays (Agilent) to compare gene expression patterns before infection, at 12h, 18h and 24h post-infection (PI). Furthermore, we combined this approach with laser capture microdissection of MEC isolated from frozen slides of mammary tissue to study some specific genes at the late stage of infection (30h PI). We show that at 18h PI, before the burst of somatic cells in milk, MEC play an important role in the recruitment and activation of inflammatory cells through the IL-8 signaling pathways. Then, at the late stage of infection (30h PI), the contribution of MEC in immune response changes to produce different acute phase proteins, including SAA3, serpin A1 and PTX3. These cells also express factors that contribute directly to fighting infection, such as S100A12. In summary, we demonstrate for the first time in vivo how MEC orchestrate innate immune response during an IMI with S. aureus in the goat species. We report here new opportunities to assess the dynamics of gene expression in the mammary gland, thus providing significant advances in the understanding of MEC immune capacity.M-bM-^@M-^BFurthermore, the production of some molecules by MEC, in the early stages of IMI, could provide sensitive biomarkers for early detection and therefore, treatment of mastitis. Experiments were performed using ovine microarrays (Agilent) to compare gene expression patterns before infection, at 12h, 18h and 24h post-infection (PI). 20 sample records; mono-colour experimental design