Supplementing with L-Tryptophan Increases Medium Protein and Alters Expression of Genes and Proteins Involved in Milk Protein Synthesis and Energy Metabolism in Bovine Mammary Cells
The objective of this study was to investigate the effects of supplementing with L-tryptophan (L-Trp) on milk protein synthesis using an immortalized bovine mammary epithelial (MAC-T) cell line. Cells were treated with 0, 0.3, 0.6, 0.9, 1.2, and 1.5 mM of supplemental L-Trp, and the most efficient t...
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MDPI AG
2021-03-01
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| Series: | International Journal of Molecular Sciences |
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| author | Jay Ronel V. Conejos Jalil Ghassemi Nejad Jung-Eun Kim Jun-Ok Moon Jae-Sung Lee Hong-Gu Lee |
| author_facet | Jay Ronel V. Conejos Jalil Ghassemi Nejad Jung-Eun Kim Jun-Ok Moon Jae-Sung Lee Hong-Gu Lee |
| author_sort | Jay Ronel V. Conejos |
| collection | DOAJ |
| description | The objective of this study was to investigate the effects of supplementing with L-tryptophan (L-Trp) on milk protein synthesis using an immortalized bovine mammary epithelial (MAC-T) cell line. Cells were treated with 0, 0.3, 0.6, 0.9, 1.2, and 1.5 mM of supplemental L-Trp, and the most efficient time for protein synthesis was determined by measuring cell, medium, and total protein at 0, 24, 48, 72, and 96 h. Time and dose tests showed that the 48 h incubation time and a 0.9 mM dose of L-Trp were the optimal values. The mechanism of milk protein synthesis was elucidated through proteomic analysis to identify the metabolic pathway involved. When L-Trp was supplemented, extracellular protein (medium protein) reached its peak at 48 h, whereas intracellular cell protein reached its peak at 96 h with all L-Trp doses. β-casein mRNA gene expression and genes related to milk protein synthesis, such as mammalian target of rapamycin (mTOR) and ribosomal protein 6 (RPS6) genes, were also stimulated (<i>p</i> < 0.05). Overall, there were 51 upregulated and 59 downregulated proteins, many of which are involved in protein synthesis. The results of protein pathway analysis showed that L-Trp stimulated glycolysis, the pentose phosphate pathway, and ATP synthesis, which are pathways involved in energy metabolism. Together, these results demonstrate that L-Trp supplementation, particularly at 0.9 mM, is an effective stimulus in β-casein synthesis by stimulating genes, proteins, and pathways related to protein and energy metabolism. |
| first_indexed | 2024-03-10T13:25:26Z |
| format | Article |
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| issn | 1661-6596 1422-0067 |
| language | English |
| last_indexed | 2024-03-10T13:25:26Z |
| publishDate | 2021-03-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | International Journal of Molecular Sciences |
| spelling | doaj.art-b4aa1ecaef0c4f4daea5a3b9a9a1e3842023-11-21T09:41:26ZengMDPI AGInternational Journal of Molecular Sciences1661-65961422-00672021-03-01225275110.3390/ijms22052751Supplementing with L-Tryptophan Increases Medium Protein and Alters Expression of Genes and Proteins Involved in Milk Protein Synthesis and Energy Metabolism in Bovine Mammary CellsJay Ronel V. Conejos0Jalil Ghassemi Nejad1Jung-Eun Kim2Jun-Ok Moon3Jae-Sung Lee4Hong-Gu Lee5Department of Animal Science and Technology, Konkuk University, Seoul 05029, KoreaDepartment of Animal Science and Technology, Konkuk University, Seoul 05029, KoreaDepartment of Animal Science and Technology, Konkuk University, Seoul 05029, KoreaInstitute of Integrated Technology, CJ CheilJedang, Suwon 16495, KoreaDepartment of Animal Science and Technology, Konkuk University, Seoul 05029, KoreaDepartment of Animal Science and Technology, Konkuk University, Seoul 05029, KoreaThe objective of this study was to investigate the effects of supplementing with L-tryptophan (L-Trp) on milk protein synthesis using an immortalized bovine mammary epithelial (MAC-T) cell line. Cells were treated with 0, 0.3, 0.6, 0.9, 1.2, and 1.5 mM of supplemental L-Trp, and the most efficient time for protein synthesis was determined by measuring cell, medium, and total protein at 0, 24, 48, 72, and 96 h. Time and dose tests showed that the 48 h incubation time and a 0.9 mM dose of L-Trp were the optimal values. The mechanism of milk protein synthesis was elucidated through proteomic analysis to identify the metabolic pathway involved. When L-Trp was supplemented, extracellular protein (medium protein) reached its peak at 48 h, whereas intracellular cell protein reached its peak at 96 h with all L-Trp doses. β-casein mRNA gene expression and genes related to milk protein synthesis, such as mammalian target of rapamycin (mTOR) and ribosomal protein 6 (RPS6) genes, were also stimulated (<i>p</i> < 0.05). Overall, there were 51 upregulated and 59 downregulated proteins, many of which are involved in protein synthesis. The results of protein pathway analysis showed that L-Trp stimulated glycolysis, the pentose phosphate pathway, and ATP synthesis, which are pathways involved in energy metabolism. Together, these results demonstrate that L-Trp supplementation, particularly at 0.9 mM, is an effective stimulus in β-casein synthesis by stimulating genes, proteins, and pathways related to protein and energy metabolism.https://www.mdpi.com/1422-0067/22/5/2751L-tryptophanamino acidsMAC-T cellproteomicsomicsβ-casein |
| spellingShingle | Jay Ronel V. Conejos Jalil Ghassemi Nejad Jung-Eun Kim Jun-Ok Moon Jae-Sung Lee Hong-Gu Lee Supplementing with L-Tryptophan Increases Medium Protein and Alters Expression of Genes and Proteins Involved in Milk Protein Synthesis and Energy Metabolism in Bovine Mammary Cells International Journal of Molecular Sciences L-tryptophan amino acids MAC-T cell proteomics omics β-casein |
| title | Supplementing with L-Tryptophan Increases Medium Protein and Alters Expression of Genes and Proteins Involved in Milk Protein Synthesis and Energy Metabolism in Bovine Mammary Cells |
| title_full | Supplementing with L-Tryptophan Increases Medium Protein and Alters Expression of Genes and Proteins Involved in Milk Protein Synthesis and Energy Metabolism in Bovine Mammary Cells |
| title_fullStr | Supplementing with L-Tryptophan Increases Medium Protein and Alters Expression of Genes and Proteins Involved in Milk Protein Synthesis and Energy Metabolism in Bovine Mammary Cells |
| title_full_unstemmed | Supplementing with L-Tryptophan Increases Medium Protein and Alters Expression of Genes and Proteins Involved in Milk Protein Synthesis and Energy Metabolism in Bovine Mammary Cells |
| title_short | Supplementing with L-Tryptophan Increases Medium Protein and Alters Expression of Genes and Proteins Involved in Milk Protein Synthesis and Energy Metabolism in Bovine Mammary Cells |
| title_sort | supplementing with l tryptophan increases medium protein and alters expression of genes and proteins involved in milk protein synthesis and energy metabolism in bovine mammary cells |
| topic | L-tryptophan amino acids MAC-T cell proteomics omics β-casein |
| url | https://www.mdpi.com/1422-0067/22/5/2751 |
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