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:A series of experiments to establish a bovine developing mammary gland gene expression signature, identify genes differentially expressed in bovine lactating mammary gland, and to establish the false positive rate of the BMAM microarray Keywords = gene expression, differential expression, lactation, development, physiology, bovine, mammary, microarray, EST, cDNA Keywords: repeat sample
Project description:<p>Inoculation with homofermentative lactic acid bacteria (LAB) effectively enhances the silage quality of forages. Moreover, feeding such LAB-inoculated silage modulates rumen microbiota composition and metabolites, thereby improving ruminant production performance. Nevertheless, the specific mechanism through which LAB inoculants regulate the silage–rumen–mammary gland axis remains unclear.</p><p>Inoculation with homofermentative Lactiplantibacillus plantarum BX62 improved the alfalfa silage quality. Dairy goats fed the BX62 group silage showed significantly higher milk fat content compared to the control group (no inoculation) (P < 0.05). Integrated analysis of silage microbial metabolomics and experimental validation revealed a significant increase in flavonoid content in the BX62 silage. This was attributed to microbial community restructuring and secretion of carbohydrate-active enzymes (CAZymes), which facilitated plant cell wall degradation and flavonoid release. Rumen metagenomic assembly and binning indicated that feeding flavonoid-rich BX62 silage induced the proliferation of flavonoid-degrading microbes and reshaped the rumen microbiota, which resulted in the upregulation of CAZymes and energy metabolic pathways (e.g., ko00620 Pyruvate metabolism), and enhanced fiber degradation and volatile fatty acid (VFA) production in the rumen. Consequently, acetate-dependent milk fat synthesis was promoted in BX62 group goats as showed by the elevated expressions of acetyl-CoA carboxylase 1 (ACC1), fatty acid synthase (FASN) and acyl-CoA synthetase short-chain family member 2 (ACSS2) in mammary gland. Moreover, four milk fat-positively correlated bacteria species (Eggerthellaceae bacterium, Clostridioides difficile, Candidatus Limivicinus sp., and Collinsella aerofaciens) harboring flavonoid-degrading genes proliferated with elevated flavonoid concentrations in the rumen. In vitro trial further confirmed flavonoid degradation capability in both C. difficile and A. equolifaciens (family Eggerthellaceae), and dose-dependent growth promotion in A. equolifaciens. These results demonstrate that silage-derived flavonoids drive rumen microbiome remodeling and promote mammary lipogenesis through a silage-rumen microbiota-mammary gland triad mechanism.</p>
Project description:To investigate the impact of macrophages on cell population of mammary gland, we performed the single cell RNA sequencing of the macrophage-depleted mammary gland compared with control.
Project description:<p>Inoculation with homofermentative lactic acid bacteria (LAB) effectively enhances the silage quality of forages. Moreover, feeding such LAB-inoculated silage modulates rumen microbiota composition and metabolites, thereby improving ruminant production performance. Nevertheless, the specific mechanism through which LAB inoculants regulate the silage–rumen–mammary gland axis remains unclear.</p><p>Inoculation with homofermentative <em>Lactiplantibacillus plantarum</em> BX62 improved the alfalfa silage quality. Dairy goats fed the BX62 group silage showed significantly higher milk fat content compared to the control group (no inoculation) (<em>P</em> < 0.05). Integrated analysis of silage microbial metabolomics and experimental validation revealed a significant increase in flavonoid content in the BX62 silage. This was attributed to microbial community restructuring and secretion of carbohydrate-active enzymes (CAZymes), which facilitated plant cell wall degradation and flavonoid release. Rumen metagenomic assembly and binning indicated that feeding flavonoid-rich BX62 silage induced the proliferation of flavonoid-degrading microbes and reshaped the rumen microbiota, which resulted in the upregulation of CAZymes and energy metabolic pathways (e.g., ko00620 Pyruvate metabolism), and enhanced fiber degradation and volatile fatty acid (VFA) production in the rumen. Consequently, acetate-dependent milk fat synthesis was promoted in BX62 group goats as showed by the elevated expressions of acetyl-CoA carboxylase 1 (ACC1), fatty acid synthase (FASN) and acyl-CoA synthetase short-chain family member 2 (ACSS2) in mammary gland. Moreover, four milk fat-positively correlated bacteria species (<em>Eggerthellaceae</em> bacterium, <em>Clostridioides difficile</em>, <em>Candidatus Limivicinus</em> sp., and <em>Collinsella aerofaciens</em>) harboring flavonoid-degrading genes proliferated with elevated flavonoid concentrations in the rumen. <em>In vitro</em> trial further confirmed flavonoid degradation capability in both <em>C. difficile</em> and <em>A. equolifaciens</em> (family <em>Eggerthellaceae</em>), and dose-dependent growth promotion in <em>A. equolifaciens</em>. These results demonstrate that silage-derived flavonoids drive rumen microbiome remodeling and promote mammary lipogenesis through a silage-rumen microbiota-mammary gland triad mechanism.</p>
Project description:The bovine mammary gland has a heterogeneous epithelial population which comprises terminally differentiated luminal and myoepithelial cells but also bipotent or lineage restricted progenitors and adult stem cells. The aim of our study was to use a novel surface marker (P-Cadherin) to characterize different mammary subpopulation, to sort adult stem cells with better enrichment and to perform whole RNA-seq among sorted population to identify biological processes or molecular functions associated gene enrichment. We found that only the CD49fhigh/PCadherinneg was enriched for adult mammary stem cells, while in other fractions we could detect luminal progenitors. Analysis of functional enrichments showed that in the stem cell compartment proliferation associated genes were downregulated, while genes relating to adhesion to ECM and to other neighboring cells were upregulated.
Project description:T cells accumulate in the mammary gland during pregnancy and lactation. In order to understand the diversity, transcriptional states, TCR repertoire, and function of mammary gland T cells, and how these change during pregnancy and lactation compared to homeostasis, we performed single cell RNA sequencing on mammary gland T cells in mice.
Project description:Mastitis in dairy cattle can result from infection by a range of microorganisms but is principally caused by coliform bacteria and gram positive bacteria such as Staphylococcus aureus (S. aureus). The former species are often acquired by environmental contamination while S. aureus is particularly problematic due to its resistance to antibiotic treatments and ability to reside within mammary tissue in a chronic, subclinical state. The transcriptional and translational responses within bovine mammary epithelial tissue subjected to intramammary challenge with S. aureus are poorly characterised, particularly at the earliest stages of infection. A Bovine Innate Immune Microarray was employed to measure changes in gene expression occurring in bovine mammary tissues sampled from three dairy cows after a brief and graded intramammary challenge with a virulent strain of S. aureus. This SuperSeries is composed of the SubSeries listed below.
Project description:MicroRNAs (miRNAs) are small noncoding RNAs that participate in regulation of gene expression. Their role during mammary gland development is still largely unknown. In the present study, we performed a microarray analysis to identify miRNAs associated with high mammogenic potential of bovine mammary gland. We identified 54 miRNAs differing significantly between mammary tissue of dairy (Holstein-Friesian, HF) and beef (Limousine, LM) post-pubertal heifers. Fifty two miRNAs had higher expression in the mammary tissue of LM heifers. Enrichment analyses for targeted genes revealed that the major differences between miRNA expression in the mammary gland of HF vs. LM were associated with regulation of signalling pathways crucial for mammary gland development, such as: TGF-beta, insulin, WNT and inflammatory pathways. Moreover, a number of genes potentially targeted by differentially expressed miRNAs was associated with mammary stem cells’ activity. These data indicate that in dairy cattle high developmental potential of the mammary gland, leading to high milk productivity, not only depends on central neuro-endocrine regulation but also on specific miRNA expression pattern.