Real-time quantitative PCR analysis of goat mammary glands in peak-lactation and late-lactation periods
ABSTRACT: In comparison with cow milk, goat (Capra hircus) milk contains much higher levels of unsaturated fatty acids, as well as higher levels of total fat, proteins, carbohydrates, calcium, and vitamins.The main objective of the present study was to better define the relationship of known miRNAs regulating milk fat metabolism. Our main purpose is to search for some known miRNAs regulating milk fat metabolism, to this end, we screened potential miRNAs with differential expression between peak-lactation and non-lactation. qPCR gene expression profiling. Monocytes from three healthy goats (3 year old) of similar body weight. We screened a series of potential miRNAs involved in regulation of milk metabolism.
Project description:Milk is the primary source of nutrition for young mammals including humans. The nutritional value of milk is mainly attributable to fats and proteins fractions. In comparison to cow milk, goat milk contains greater amounts of total fat, including much higher levels of the beneficial unsaturated fatty acids. MicroRNAs (miRNAs), a well-defined group of small RNAs containing about 22 nucleotides (nt), participate in various metabolic processes across species. However, little is known regarding the role of miRNAs in regulating goat milk composition. In the present study, we performed high-throughput sequencing to identify mammary gland-enriched miRNAs in lactating goats. We identified 30 highly expressed miRNAs in the mammary gland, including miR-103. Further studies revealed that miR-103 expression correlates with the lactation. Further functional analysis showed that over-expression of miR-103 in mammary gland epithelial cells increases transcription of genes associated with milk fat synthesis, resulting in an up-regulation of fat droplet formation, triglyceride accumulation, and the proportion of unsaturated fatty acids. This study provides new insight into the functions of miR-103, as well as the molecular mechanisms that regulate milk fat synthesis.
Project description:Human milk (breastmilk) is much more than nutrition for the infant, containing an array of regulatory agents with immunoprotective and developmental functions. Amongst those, microRNAs (miRNAs) have recently been identified, with their properties, roles, origin and distribution in breastmilk as well as in the mammary gland being still undetermined. In this study, we examined the miRNA profile of different fractions of human milk (cells and lipids) using the OpenArray system (Applied Biosystems, 770 miRNA species measured per sample) and compared it with maternal peripheral blood mononuclear cells (PBMCs) and plasma. Although PBMCs were the richest group in miRNA species, plasma showed very low expression pattern. Thus, the human milk fractions (cells, lipid) and skim milk (not being investigated in this study) were found to conserve higher levels of miRNAs than blood in general. Specifically, human milk cell miRNA quantity was found relatively close to PBMCs, and higher than milk lipids. Correlation and clustering analyses indicated that miRNA expression and types of milk cells were highly similar to those in lipids. Milk miRNAs showed a slight correlation to PBMCs, so PBMCs potentially are not contributing to milk miRNAs. Plasma was different to all other three groups in miRNA content and expression pattern. Further, two infant formulae (a plant-based and a cow milk-based) were compared to human milk and found to contain significantly fewer miRNA species than human milk cells and lipids (p>0.001). Taken together with previous studies on miRNAs, our findings demonstrate that human milk is one of the richest sources of miRNAs among human body fluids. As a non-invasive and plentiful source of miRNAs, human milk could be used as a disease biomarker for the mammary gland, with potential in assessing lactation performance. Finally, gene target and pathways analyses identified several target mRNAs regulated by miRNAs found to be abundant in breastmilk. Given the recently identified stability and function of food-derived miRNAs in regulating mammalian genes, we propose that breastmilk is a rich source of miRNA ingested by the infant during the first months of life, and which potentially contribute to early infant development. 10 exclusively breastfeeding dyads were recruited. 10 whole milk and 10 whole blood samples were collected and fractionated to obtain 10 milk cells, 10 milk lipid, 10 mononeucleoted blood cells (PBMCs), and 10 plasma. In addition to the above 40 samples, 2 infant formula were profiled. 4 different extraction kits were used, miRNeasy mini Kit for human milk cell and PBMC samples. miRCURY RNA Isolation-Biofluids Kit for human milk lipid samples and both infant formulae. mirVana PARIS Kit for plasma samples. NanoDrop 2000 and Bioanalyzer 2100 were used to determine concentration and purity of the extracted miRNA from all samples (n=42). miRNA OpenArray panel system (Life Technologies, CA, USA) was used to profile 754 human mature miRNAs in samples. RNU48, RNU44 and U6 rRNA were used as housekeeping controls for normalisation. ath-miR159a was used as a negative control for human samples. GeneGO and Ingenuity Pathway Analysis were used to determine biological pathways. Please note that normalization of miRNAs was done in R but without generating deltaCT values, thus  only the list of normalized miRNA with Ct vlaue between 8 and 29 and that detected in at least 4 samples out of 10 analysed in each group is provided ('normalized_miRNAs_list.txt')  the sample data tables contain raw data.
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. Eight small RNA libraries in porcine breast milk exosomes of six lactigenous stages (0, 3, 7, 14, 21 and 28 days after birth) from three female pigs were sequenced.
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. Milk fat mRNA profiles were generated from Day 2 and mature milk samples obtained from lactating mothers
Project description:Breast milk is the primary source of nutrition for newborns, and is rich in immunological components. MicroRNAs (miRNAs) are present in various body fluids and 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 could regulate target gene expression and recipient cell function. Here, we analyzed the lactation-related miRNA expression profiles in porcine milk exosomes across the entire lactation period (newborn to 28 days after birth) by a deep sequencing. We found that immune-related miRNAs are present and enriched in breast milk exosomes (p<10(-16), ?(2) test) and are generally resistant to relatively harsh conditions. Notably, these exosomal miRNAs are present in higher numbers in the colostrums than in mature milk. It was higher in the serum of colostrum-only fed piglets compared with the mature milk-only fed piglets. These immune-related miRNA-loaded exosomes in breast milk may be transferred into the infant body via the digestive tract. These observations are a prelude to in-depth investigations of the essential roles of breast milk in the development of the infant's immune system.
Project description:The study examined microRNA (miRNA) expression and regulatory patterns during an entire bovine lactation cycle. Total RNA from milk fat samples collected at the lactogenesis (LAC, day1 [D1] and D7), galactopoiesis (GAL, D30, D70, D130, D170 and D230) and involution (INV, D290 and when milk production dropped to 5?kg/day) stages from 9 cows was used for miRNA sequencing. A total of 475 known and 238 novel miRNAs were identified. Fifteen abundantly expressed miRNAs across lactation stages play regulatory roles in basic metabolic, cellular and immunological functions. About 344, 366 and 209 miRNAs were significantly differentially expressed (DE) between GAL and LAC, INV and GAL, and INV and LAC stages, respectively. MiR-29b/miR-363 and miR-874/miR-6254 are important mediators for transition signals from LAC to GAL and from GAL to INV, respectively. Moreover, 58 miRNAs were dynamically DE in all lactation stages and 19 miRNAs were significantly time-dependently DE throughout lactation. Relevant signalling pathways for transition between lactation stages are involved in apoptosis (PTEN and SAPK/JNK), intracellular signalling (protein kinase A, TGF-? and ERK5), cell cycle regulation (STAT3), cytokines, hormones and growth factors (prolactin, growth hormone and glucocorticoid receptor). Overall, our data suggest diverse, temporal and physiological signal-dependent regulatory and mediator functions for miRNAs during lactation.
Project description:BACKGROUND:Pigeon crop has the unique ability to produce a nutrient rich substance termed pigeon 'milk' (PM), which has functional resemblance with the mammalian milk. Previous researches have demonstrated that a large number of exosomes and exosomal miRNAs exist in mammalian milk, and many of them are associated with immunity, growth and development. However, to date, little is known about the exosomes and exosomal miRNAs in PM. RESULTS:In this study, we isolated the exosomes from PM and used small RNA sequencing to investigate the distribution and expression profiles of exosomal miRNAs. A total of 301 mature miRNAs including 248 conserved and 53 novel miRNAs were identified in five lactation stages i.e. 1d, 5d, 10d, 15d, and 20d. From these, four top 10 conserved miRNAs (cli-miR-21-5p, cli-miR-148a-3p, cli-miR-10a-5p and cli-miR-26a-5p) were co-expressed in all five stages. We speculate that these miRNAs may have important role in the biosynthesis and metabolism of PM. Moreover, similar to the mammalian milk, a significant proportion of immune and growth-related miRNAs were also present and enriched in PM exosomes. Furthermore, we also identified 41 orthologous miRNAs group (giving rise to 81 mature miRNA) commonly shared with PM, human, bovine and porcine breast milk. Additionally, functional enrichment analysis revealed the role of exosomal miRNAs in organ development and in growth-related pathways including the MAPK, Wnt and insulin pathways. CONCLUSIONS:To sum-up, this comprehensive analysis will contribute to a better understanding of the underlying functions and regulatory mechanisms of PM in squabs.
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:BACKGROUND: The molecular events associated with regulation of milk fat synthesis in the bovine mammary gland remain largely unknown. Our objective was to study mammary tissue mRNA expression via quantitative PCR of 45 genes associated with lipid synthesis (triacylglycerol and phospholipids) and secretion from the late pre-partum/non-lactating period through the end of subsequent lactation. mRNA expression was coupled with milk fatty acid (FA) composition and calculated indexes of FA desaturation and de novo synthesis by the mammary gland. RESULTS: Marked up-regulation and/or % relative mRNA abundance during lactation were observed for genes associated with mammary FA uptake from blood (LPL, CD36), intracellular FA trafficking (FABP3), long-chain (ACSL1) and short-chain (ACSS2) intracellular FA activation, de novo FA synthesis (ACACA, FASN), desaturation (SCD, FADS1), triacylglycerol synthesis (AGPAT6, GPAM, LPIN1), lipid droplet formation (BTN1A1, XDH), ketone body utilization (BDH1), and transcription regulation (INSIG1, PPARG, PPARGC1A). Change in SREBF1 mRNA expression during lactation, thought to be central for milk fat synthesis regulation, was < or =2-fold in magnitude, while expression of INSIG1, which negatively regulates SREBP activation, was >12-fold and had a parallel pattern of expression to PPARGC1A. Genes involved in phospholipid synthesis had moderate up-regulation in expression and % relative mRNA abundance. The mRNA abundance and up-regulation in expression of ABCG2 during lactation was markedly high, suggesting a biological role of this gene in milk synthesis/secretion. Weak correlations were observed between both milk FA composition and desaturase indexes (i.e., apparent SCD activity) with mRNA expression pattern of genes measured. CONCLUSION: A network of genes participates in coordinating milk fat synthesis and secretion. Results challenge the proposal that SREBF1 is central for milk fat synthesis regulation and highlight a pivotal role for a concerted action among PPARG, PPARGC1A, and INSIG1. Expression of SCD, the most abundant gene measured, appears to be key during milk fat synthesis. The lack of correlation between gene expression and calculated desaturase indexes does not support their use to infer mRNA expression or enzyme activity (e.g., SCD). Longitudinal mRNA expression allowed development of transcriptional regulation networks and an updated model of milk fat synthesis regulation.
Project description:Abundant miRNAs have been identified in milk and mammary gland tissues of different species. Typically, RNA in milk can be extracted from different fractions including fat, whey and cells and the mRNA transcriptome of milk could serve as an indicator of the transcriptome of mammary gland tissue. However, it has not been adequately validated if the miRNA transcriptome of any milk fraction could be representative of that of mammary gland tissue. The objectives of this study were to (1) characterize the miRNA expression spectra from three milk fractions- fat, whey and cells; (2) compare miRNome profiles of milk fractions (fat, whey and cells) with mammary gland tissue miRNome, and (3) determine which milk fraction miRNome profile could be a better representative of the miRNome profile of mammary gland tissue. Milk from four healthy Canadian Holstein cows in mid lactation was collected and fractionated. Total RNA extracted from each fraction was used for library preparation followed by small RNA sequencing. In addition, miRNA transcripts of mammary gland tissues from twelve Holstein cows in our previous study were used to compare our data. We identified 210, 200 and 249 known miRNAs from milk fat, whey and cells, respectively, with 188 universally expressed in the three fractions. In addition, 33, 31 and 36 novel miRNAs from milk fat, whey and cells were identified, with 28 common in the three fractions. Among 20 most highly expressed miRNAs in each fraction, 14 were expressed in common and 11 were further shared with mammary gland tissue. The three milk fractions demonstrated a clear separation from each other using a hierarchical cluster analysis with milk fat and whey being most closely related. The miRNome correlation between milk fat and mammary gland tissue (rmean = 0.866) was significantly higher than the other two pairs (p < 0.01), whey/mammary gland tissue (rmean = 0.755) and milk cell/mammary gland tissue (rmean = 0.75), suggesting that milk fat could be an alternative non-invasive source of RNA in assessing miRNA activities in bovine mammary gland. Predicted target genes (1802) of 14 highly expressed miRNAs in milk fractions were enriched in fundamental cellular functions, infection, organ and tissue development. Furthermore, some miRNAs were highly enriched (FDR <0.05) in milk whey (3), cells (11) and mammary gland tissue (14) suggesting specific regulatory functions in the various fractions. In conclusion, we have obtained a comprehensive miRNA profile of the different milk fractions using high throughput sequencing. Our comparative analysis showed that miRNAs from milk fat accurately portrayed the miRNome of mammary gland tissue. Functional annotation of the top expressed miRNAs in milk confirmed their critical regulatory roles in mammary gland functions and potentially to milk recipients.