IIAEK Targets Intestinal Alkaline Phosphatase (IAP) to Improve Cholesterol Metabolism with a Specific Activation of IAP and Downregulation of ABCA1
IIAEK (Ile-Ile-Ala-Glu-Lys, lactostatin) is a novel cholesterol-lowering pentapeptide derived from bovine milk β-lactoglobulin. However, the molecular mechanisms underlying the IIAEK-mediated suppression of intestinal cholesterol absorption are unknown. Therefore, we evaluated the effects of IIAEK o...
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| Format: | Article |
| Language: | English |
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MDPI AG
2020-09-01
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| Series: | Nutrients |
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| Online Access: | https://www.mdpi.com/2072-6643/12/9/2859 |
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| author | Asahi Takeuchi Kentaro Hisamatsu Natsuki Okumura Yuki Sugimitsu Emiko Yanase Yoshihito Ueno Satoshi Nagaoka |
| author_facet | Asahi Takeuchi Kentaro Hisamatsu Natsuki Okumura Yuki Sugimitsu Emiko Yanase Yoshihito Ueno Satoshi Nagaoka |
| author_sort | Asahi Takeuchi |
| collection | DOAJ |
| description | IIAEK (Ile-Ile-Ala-Glu-Lys, lactostatin) is a novel cholesterol-lowering pentapeptide derived from bovine milk β-lactoglobulin. However, the molecular mechanisms underlying the IIAEK-mediated suppression of intestinal cholesterol absorption are unknown. Therefore, we evaluated the effects of IIAEK on intestinal cholesterol metabolism in a human intestinal model using Caco-2 cells. We found that IIAEK significantly reduced the expression of intestinal cholesterol metabolism-associated genes, particularly that of the ATP-binding cassette transporter A1 (ABCA1). Subsequently, we chemically synthesized a novel molecular probe, IIXEK, which can visualize a complex of target proteins interacting with photoaffinity-labeled IIAEK by fluorescent substances. Through photoaffinity labeling and MS analysis with IIXEK for the rat small intestinal mucosa and intestinal lipid raft fractions of Caco-2 cells, we identified intestinal alkaline phosphatase (IAP) as a specific molecule interacting with IIAEK and discovered the common IIAEK-binding amino acid sequence, GFYLFVEGGR. IIAEK significantly increased IAP mRNA and protein levels while decreasing ABCA1 mRNA and protein levels in Caco-2 cells. In conclusion, we found that IIAEK targets IAP to improve cholesterol metabolism via a novel signaling pathway involving the specific activation of IAP and downregulation of intestinal ABCA1. |
| first_indexed | 2024-03-10T16:14:09Z |
| format | Article |
| id | doaj.art-fcb78244da2f42038dfd57c8c1e865fb |
| institution | Directory Open Access Journal |
| issn | 2072-6643 |
| language | English |
| last_indexed | 2024-03-10T16:14:09Z |
| publishDate | 2020-09-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Nutrients |
| spelling | doaj.art-fcb78244da2f42038dfd57c8c1e865fb2023-11-20T14:13:26ZengMDPI AGNutrients2072-66432020-09-01129285910.3390/nu12092859IIAEK Targets Intestinal Alkaline Phosphatase (IAP) to Improve Cholesterol Metabolism with a Specific Activation of IAP and Downregulation of ABCA1Asahi Takeuchi0Kentaro Hisamatsu1Natsuki Okumura2Yuki Sugimitsu3Emiko Yanase4Yoshihito Ueno5Satoshi Nagaoka6Laboratory of Molecular Function of Food, Department of Applied Life Science, Faculty of Applied Biological Sciences, Gifu University, 1-1 Yanagido, Gifu 501-1193, JapanLaboratory of Molecular Function of Food, Department of Applied Life Science, Faculty of Applied Biological Sciences, Gifu University, 1-1 Yanagido, Gifu 501-1193, JapanLaboratory of Molecular Function of Food, Department of Applied Life Science, Faculty of Applied Biological Sciences, Gifu University, 1-1 Yanagido, Gifu 501-1193, JapanLaboratory of Molecular Function of Food, Department of Applied Life Science, Faculty of Applied Biological Sciences, Gifu University, 1-1 Yanagido, Gifu 501-1193, JapanLaboratory of Bio-organic Chemistry, Department of Applied Life Science, Faculty of Applied Biological Sciences, Gifu University, 1-1 Yanagido, Gifu 501-1193, JapanLaboratory of Bio-organic Chemistry, Department of Applied Life Science, Faculty of Applied Biological Sciences, Gifu University, 1-1 Yanagido, Gifu 501-1193, JapanLaboratory of Molecular Function of Food, Department of Applied Life Science, Faculty of Applied Biological Sciences, Gifu University, 1-1 Yanagido, Gifu 501-1193, JapanIIAEK (Ile-Ile-Ala-Glu-Lys, lactostatin) is a novel cholesterol-lowering pentapeptide derived from bovine milk β-lactoglobulin. However, the molecular mechanisms underlying the IIAEK-mediated suppression of intestinal cholesterol absorption are unknown. Therefore, we evaluated the effects of IIAEK on intestinal cholesterol metabolism in a human intestinal model using Caco-2 cells. We found that IIAEK significantly reduced the expression of intestinal cholesterol metabolism-associated genes, particularly that of the ATP-binding cassette transporter A1 (ABCA1). Subsequently, we chemically synthesized a novel molecular probe, IIXEK, which can visualize a complex of target proteins interacting with photoaffinity-labeled IIAEK by fluorescent substances. Through photoaffinity labeling and MS analysis with IIXEK for the rat small intestinal mucosa and intestinal lipid raft fractions of Caco-2 cells, we identified intestinal alkaline phosphatase (IAP) as a specific molecule interacting with IIAEK and discovered the common IIAEK-binding amino acid sequence, GFYLFVEGGR. IIAEK significantly increased IAP mRNA and protein levels while decreasing ABCA1 mRNA and protein levels in Caco-2 cells. In conclusion, we found that IIAEK targets IAP to improve cholesterol metabolism via a novel signaling pathway involving the specific activation of IAP and downregulation of intestinal ABCA1.https://www.mdpi.com/2072-6643/12/9/2859IIAEKalkaline phosphatasephotoaffinity labelingCaco-2 cellscholesterolABCA1 |
| spellingShingle | Asahi Takeuchi Kentaro Hisamatsu Natsuki Okumura Yuki Sugimitsu Emiko Yanase Yoshihito Ueno Satoshi Nagaoka IIAEK Targets Intestinal Alkaline Phosphatase (IAP) to Improve Cholesterol Metabolism with a Specific Activation of IAP and Downregulation of ABCA1 Nutrients IIAEK alkaline phosphatase photoaffinity labeling Caco-2 cells cholesterol ABCA1 |
| title | IIAEK Targets Intestinal Alkaline Phosphatase (IAP) to Improve Cholesterol Metabolism with a Specific Activation of IAP and Downregulation of ABCA1 |
| title_full | IIAEK Targets Intestinal Alkaline Phosphatase (IAP) to Improve Cholesterol Metabolism with a Specific Activation of IAP and Downregulation of ABCA1 |
| title_fullStr | IIAEK Targets Intestinal Alkaline Phosphatase (IAP) to Improve Cholesterol Metabolism with a Specific Activation of IAP and Downregulation of ABCA1 |
| title_full_unstemmed | IIAEK Targets Intestinal Alkaline Phosphatase (IAP) to Improve Cholesterol Metabolism with a Specific Activation of IAP and Downregulation of ABCA1 |
| title_short | IIAEK Targets Intestinal Alkaline Phosphatase (IAP) to Improve Cholesterol Metabolism with a Specific Activation of IAP and Downregulation of ABCA1 |
| title_sort | iiaek targets intestinal alkaline phosphatase iap to improve cholesterol metabolism with a specific activation of iap and downregulation of abca1 |
| topic | IIAEK alkaline phosphatase photoaffinity labeling Caco-2 cells cholesterol ABCA1 |
| url | https://www.mdpi.com/2072-6643/12/9/2859 |
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