Intestinal alkaline phosphatase is a receptor for cholesterol-lowering pentapeptide IIAEK and regulates cholesterol homeostasis in mice

Abstract Dietary proteins are absorbed by the intestine as amino acids or peptides. Di- or tripeptides are absorbed via the intestinal peptide transporter 1 (PepT1); however, the intestinal target of oligopeptides larger than tetrapeptides remain unclear, posing a major contradiction in the current...

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Main Authors: Asahi Takeuchi, Natsuki Oda, Keigo Takada, Ryosuke Mori, Takumi Aida, Arata Banno, Akio Ebihara, Satoshi Nagaoka
Format: Article
Language:English
Published: Nature Portfolio 2025-07-01
Series:Scientific Reports
Online Access:https://doi.org/10.1038/s41598-025-04722-w
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author Asahi Takeuchi
Natsuki Oda
Keigo Takada
Ryosuke Mori
Takumi Aida
Arata Banno
Akio Ebihara
Satoshi Nagaoka
author_facet Asahi Takeuchi
Natsuki Oda
Keigo Takada
Ryosuke Mori
Takumi Aida
Arata Banno
Akio Ebihara
Satoshi Nagaoka
author_sort Asahi Takeuchi
collection DOAJ
description Abstract Dietary proteins are absorbed by the intestine as amino acids or peptides. Di- or tripeptides are absorbed via the intestinal peptide transporter 1 (PepT1); however, the intestinal target of oligopeptides larger than tetrapeptides remain unclear, posing a major contradiction in the current protein-peptide nutrition. This study aimed to explore the unidentified function of intestinal alkaline phosphatase (IAP) in regulating cholesterol metabolism using the dietary peptide IIAEK. In IAP-knockout (Akp3 -/-) mice, the IIAEK-induced amelioration of cholesterol metabolism via the suppression of intestinal cholesterol absorption was absent. Furthermore, we found that IIAEK specifically interacts with the substrate recognition sites of mouse IAP (Akp3) and human IAP. The IIAEK-human IAP complex interacts with the transmembrane glycoprotein cadherin-17 (CDH17). In conclusion, we demonstrated that IAP is pivotal for the pentapeptide IIAEK-induced amelioration of cholesterol metabolism and serves not only as an enzyme (phosphatase) but also as a glycosylphosphatidylinositol-anchored specific receptor for oligopeptide IIAEK. In addition, we suggest that human cadherin-17 plays a key role in signal transduction in the IIAEK-human IAP complex. Our findings contribute to the understanding of the molecular mechanism of intestinal sensing of oligopeptides (IIAEK) and the development of novel functional foods and medicines targeting IAP to treat lifestyle-related diseases, such as dyslipidaemia.
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spelling doaj-art-30fc61bf2eb44aada484e87ebe5ce1232025-08-20T03:38:13ZengNature PortfolioScientific Reports2045-23222025-07-0115112010.1038/s41598-025-04722-wIntestinal alkaline phosphatase is a receptor for cholesterol-lowering pentapeptide IIAEK and regulates cholesterol homeostasis in miceAsahi Takeuchi0Natsuki Oda1Keigo Takada2Ryosuke Mori3Takumi Aida4Arata Banno5Akio Ebihara6Satoshi Nagaoka7Department of Applied Life Science, Faculty of Applied Biological Sciences, Gifu UniversityDepartment of Applied Life Science, Faculty of Applied Biological Sciences, Gifu UniversityDepartment of Applied Life Science, Faculty of Applied Biological Sciences, Gifu UniversityDepartment of Applied Life Science, Faculty of Applied Biological Sciences, Gifu UniversityDepartment of Applied Life Science, Faculty of Applied Biological Sciences, Gifu UniversityDepartment of Applied Life Science, Faculty of Applied Biological Sciences, Gifu UniversityDepartment of Applied Life Science, Faculty of Applied Biological Sciences, Gifu UniversityDepartment of Applied Life Science, Faculty of Applied Biological Sciences, Gifu UniversityAbstract Dietary proteins are absorbed by the intestine as amino acids or peptides. Di- or tripeptides are absorbed via the intestinal peptide transporter 1 (PepT1); however, the intestinal target of oligopeptides larger than tetrapeptides remain unclear, posing a major contradiction in the current protein-peptide nutrition. This study aimed to explore the unidentified function of intestinal alkaline phosphatase (IAP) in regulating cholesterol metabolism using the dietary peptide IIAEK. In IAP-knockout (Akp3 -/-) mice, the IIAEK-induced amelioration of cholesterol metabolism via the suppression of intestinal cholesterol absorption was absent. Furthermore, we found that IIAEK specifically interacts with the substrate recognition sites of mouse IAP (Akp3) and human IAP. The IIAEK-human IAP complex interacts with the transmembrane glycoprotein cadherin-17 (CDH17). In conclusion, we demonstrated that IAP is pivotal for the pentapeptide IIAEK-induced amelioration of cholesterol metabolism and serves not only as an enzyme (phosphatase) but also as a glycosylphosphatidylinositol-anchored specific receptor for oligopeptide IIAEK. In addition, we suggest that human cadherin-17 plays a key role in signal transduction in the IIAEK-human IAP complex. Our findings contribute to the understanding of the molecular mechanism of intestinal sensing of oligopeptides (IIAEK) and the development of novel functional foods and medicines targeting IAP to treat lifestyle-related diseases, such as dyslipidaemia.https://doi.org/10.1038/s41598-025-04722-w
spellingShingle Asahi Takeuchi
Natsuki Oda
Keigo Takada
Ryosuke Mori
Takumi Aida
Arata Banno
Akio Ebihara
Satoshi Nagaoka
Intestinal alkaline phosphatase is a receptor for cholesterol-lowering pentapeptide IIAEK and regulates cholesterol homeostasis in mice
Scientific Reports
title Intestinal alkaline phosphatase is a receptor for cholesterol-lowering pentapeptide IIAEK and regulates cholesterol homeostasis in mice
title_full Intestinal alkaline phosphatase is a receptor for cholesterol-lowering pentapeptide IIAEK and regulates cholesterol homeostasis in mice
title_fullStr Intestinal alkaline phosphatase is a receptor for cholesterol-lowering pentapeptide IIAEK and regulates cholesterol homeostasis in mice
title_full_unstemmed Intestinal alkaline phosphatase is a receptor for cholesterol-lowering pentapeptide IIAEK and regulates cholesterol homeostasis in mice
title_short Intestinal alkaline phosphatase is a receptor for cholesterol-lowering pentapeptide IIAEK and regulates cholesterol homeostasis in mice
title_sort intestinal alkaline phosphatase is a receptor for cholesterol lowering pentapeptide iiaek and regulates cholesterol homeostasis in mice
url https://doi.org/10.1038/s41598-025-04722-w
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