scholarly journals Effect of hyperthermia on cell viability, amino acid transfer, and milk protein synthesis in bovine mammary epithelial cells

2021 ◽  
Author(s):  
Jia Zhou ◽  
Shungming Yue ◽  
Benchu Yue ◽  
Zhisheng Wang ◽  
Lizhi Wang ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Amino Acid ◽  
Epithelial Cells ◽  
Cell Viability ◽  
Milk Protein ◽  
Mammary Epithelial Cells ◽  
Mammary Epithelial ◽  
Bovine Mammary Epithelial Cells

scholarly journals Intracellular Staphylococcus aureus Infection Decreases Milk Protein Synthesis by Preventing Amino Acid Uptake in Bovine Mammary Epithelial Cells

2021 ◽  
Vol 8 ◽  
Author(s):  
Yuhao Chen ◽  
Yuze Ma ◽  
Qiang Ji ◽  
Xiaoru Yang ◽  
Xue Feng ◽  
...  
Keyword(s):  
Amino Acids ◽  
Protein Synthesis ◽  
Amino Acid ◽  
Epithelial Cells ◽  
Milk Protein ◽  
Mammary Epithelial Cells ◽  
Protein Composition ◽  
Mammary Epithelial ◽  
Bovine Mammary Epithelial Cells ◽  
Mtorc1 Signaling

Staphylococcus aureus (S. aureus) is one of the main pathogens in cow mastitis, colonizing mammary tissues and being internalized into mammary epithelial cells, causing intracellular infection in the udder. Milk that is produced by cows that suffer from mastitis due to S. aureus is associated with decreased production and changes in protein composition. However, there is limited information on how mastitis-inducing bacteria affect raw milk, particularly with regard to protein content and protein composition. The main purpose of this work was to examine how S. aureus infection affects milk protein synthesis in bovine mammary epithelial cells (BMECs). BMECs were infected with S. aureus, and milk protein and amino acid levels were determined by ELISA after S. aureus invasion. The activity of mTORC1 signaling and the transcription factors NF-κB and STAT5 and the expression of the amino acid transporters SLC1A3 and SLC7A5 were measured by western blot or immunofluorescence and RT-qPCR. S. aureus was internalized by BMECs in vitro, and the internalized bacteria underwent intracellular proliferation. Eight hours after S. aureus invasion, milk proteins were downregulated, and the level of BMECs that absorbed Glu, Asp, and Leu from the culture medium and the exogenous amino acids induced β-casein synthesis declined. Further, the activity of mTORC1 signaling, NF-κB, and STAT5 was impaired, and SLC1A3 and SLC7A5 were downregulated. Eight hours of treatment with 100 nM rapamycin inhibited NF-κB and STAT5 activity, SLC1A3 and SLC7A5 expression, and milk protein synthesis in BMECs. Thus mTORC1 regulates the expression of SLC1A3 and SLC7A5 through NF-κB and STAT5. These findings constitute a model by which S. aureus infection suppresses milk protein synthesis by decreasing amino acids uptake in BMECs.

Lactogenic hormones regulate mammary protein synthesis in bovine mammary epithelial cells via the mTOR and JAK–STAT signal pathways

2016 ◽  
Vol 56 (11) ◽  
pp. 1803 ◽  
Author(s):  
Q. Tian ◽  
H. R. Wang ◽  
M. Z. Wang ◽  
C. Wang ◽  
S. M. Liu
Keyword(s):  
Protein Synthesis ◽  
Epithelial Cells ◽  
Milk Protein ◽  
Mammary Epithelial Cells ◽  
Signal Pathway ◽  
Mammary Epithelial ◽  
Signal Pathways ◽  
Bovine Mammary Epithelial Cells ◽  
Genes Encoding ◽  
Lactogenic Hormones

The expression of CSN3, hormone receptor, the expression of genes regulating the mTOR, JAK–STAT signal pathways, and the relative content of к-casein as well as total casein were determined in the present study to explore the mechanism of the effect of lactogenic hormones on milk-protein synthesis in bovine mammary epithelial cells. The results showed that apoptosis of the cells was increased by inhibitor LY294002, while the expressions of genes encoding PKB, Rheb, PRAS40 and S6K1 in the mTOR signal pathway, JAK2, STAT5A in the JAK–STAT signal pathway, and genes encoding INSR, PRLR, NR3C1 and CSN3 were all downregulated, and the relative contents of κ-casein and total casein were decreased in the mammary epithelial cells compared with those in the control group. Comparatively, the inhibitory effects of AG-490 were more profound than those of LY294002, and the double block using both inhibitors had a greater effect than the single block. The CSN3 gene expression was downregulated and the content of milk casein was decreased by the inhibitors. In addition, the expression of the hormone receptor genes was downregulated. Our results suggest that lactogenic hormones, via their receptors in the membrane, regulated the JAK–STAT and m-TOR signal pathways, and affected cell proliferation and apoptosis, leading to changes in milk-protein synthesis.

scholarly journals Seryl-tRNA synthetase is involved in methionine stimulation of β-casein synthesis in bovine mammary epithelial cells

2019 ◽  
Vol 123 (5) ◽  
pp. 489-498 ◽  
Author(s):  
Wenting Dai ◽  
Fengqi Zhao ◽  
Jianxin Liu ◽  
Hongyun Liu
Keyword(s):  
Protein Synthesis ◽  
Cell Viability ◽  
Total Protein ◽  
Milk Protein ◽  
Mammary Epithelial Cells ◽  
Trna Synthetase ◽  
Mammary Epithelial ◽  
Bovine Mammary Epithelial Cells ◽  
Casein Synthesis ◽  
Stimulation Of

AbstractDespite the well-characterised mechanisms of amino acids (AA) regulation of milk protein synthesis in mammary glands (MG), the underlying specific AA regulatory machinery in bovine MG remains further elucidated. As methionine (Met) is one of the most important essential and limiting AA for dairy cows, it is crucial to expand how Met exerts its regulatory effects on dairy milk protein synthesis. Our previous work detected the potential regulatory role of seryl-tRNA synthetase (SARS) in essential AA (EAA)-stimulated bovine casein synthesis. Here, we investigated whether and how SARS participates in Met stimulation of casein production in bovine mammary epithelial cells (BMEC). With or without RNA interference against SARS, BMEC were treated with the medium in the absence (containing all other EAA and devoid of Met alone)/presence (containing 0·6 mm of Met in the medium devoid of Met alone) of Met. The protein abundance of β-casein and members of the mammalian target of rapamycin (mTOR) and general control nonderepressible 2 (GCN2) pathways was determined by immunoblot assay after 6 h treatment, the cell viability and cell cycle progression were determined by cell counting and propidium iodide-staining assay after 24 h treatment, and protein turnover was determined by l-[ring-3H5]phenylalanine isotope tracing assay after 48 h treatment. In the absence of Met, there was a general reduction in cell viability, total protein synthesis and β-casein production; in contrast, total protein degradation was enhanced. SARS knockdown strengthened these changes. Finally, SARS may work to promote Met-stimulated β-casein synthesis via affecting mTOR and GCN2 routes in BMEC.

Examination of methionine stimulation of gene expression in dairy cow mammary epithelial cells using RNA-sequencing

2020 ◽  
Vol 87 (2) ◽  
pp. 226-231
Author(s):  
Xiaoming Hou ◽  
Minghui Jiang ◽  
Jinyu Zhou ◽  
Shuyuan Song ◽  
Feng Zhao ◽  
...  
Keyword(s):  
Gene Expression ◽  
Protein Synthesis ◽  
Epithelial Cells ◽  
Rna Sequencing ◽  
Milk Protein ◽  
Mammary Epithelial Cells ◽  
Cell Model ◽  
Expression Profiles ◽  
Mammary Epithelial ◽  
Bovine Mammary Epithelial Cells

AbstractIn this research communication, a cell model with elevated β-CASEIN synthesis was established by stimulating bovine mammary epithelial cells with 0.6 mM methionine, and the genome-wide gene expression profiles of methionine-stimulated cells and untreated cells were investigated by RNA sequencing. A total of 458 differentially expressed genes (DEGs; 219 upregulated and 239 downregulated) were identified between the two groups. Gene Ontology (GO) analysis showed that the two highest-ranked GO terms in ‘molecular function’ category were ‘binding’ and ‘catalytic activity’, suggesting that milk protein synthesis in methionine-stimulated cells requires induction of gene expression to increase metabolic activity. Kyoto Encyclopedia of Genes and Genomes analysis revealed that within the ‘environmental information processing’ category, the subcategory that is most highly enriched for DEGs was ‘signal transduction’. cGMP-PKG, Rap1, calcium, cAMP, PI3K-AKT, MAPK, and JAK-STAT are the pathways with the highest number of DEGs, suggesting that these signaling pathways have potential roles in mediating methionine-induced milk protein synthesis in bovine mammary epithelial cells. This study provides valuable insights into the physiological and metabolic adaptations in cells stimulated with methionine. Understanding the regulation of this transition is essential for effective intervention in the lactation process.

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