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Naturally Occurring N-Terminal Fragments of Bovine Milk Osteopontin Are Transported across Models of the Intestinal Barrier

Osteopontin (OPN) is a bioactive integrin-binding protein found in high concentrations in milk, where it is present both as a full-length protein and as several N-terminally derived fragments. OPN resists gastric digestion, and via interaction with receptors in the gut or by crossing the intestinal...

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Autores principales: Christensen, Brian, Nielsen, Nanna R., Sørensen, Marie R., Jacobsen, Lotte N., Ostenfeld, Marie S., Sørensen, Esben S.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2023
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10045268/
https://www.ncbi.nlm.nih.gov/pubmed/36979872
http://dx.doi.org/10.3390/biomedicines11030893
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author Christensen, Brian
Nielsen, Nanna R.
Sørensen, Marie R.
Jacobsen, Lotte N.
Ostenfeld, Marie S.
Sørensen, Esben S.
author_facet Christensen, Brian
Nielsen, Nanna R.
Sørensen, Marie R.
Jacobsen, Lotte N.
Ostenfeld, Marie S.
Sørensen, Esben S.
author_sort Christensen, Brian
collection PubMed
description Osteopontin (OPN) is a bioactive integrin-binding protein found in high concentrations in milk, where it is present both as a full-length protein and as several N-terminally derived fragments. OPN resists gastric digestion, and via interaction with receptors in the gut or by crossing the intestinal barrier into circulation, ingested milk OPN may influence physiological processes. The aim of this study was to investigate OPN interaction with intestinal cells and its transport across models of the intestinal barrier. Immunodetection of OPN incubated with Caco-2 cells at 4 °C and 37 °C showed that OPN binds to the intestinal cells, but it is not internalised. Transepithelial transport was studied using mono- and co-cultures of Caco-2 cells and mucus-producing HT29-MTX cells in transwell membranes. OPN was shown to cross the barrier models in a time-, temperature-, and energy-dependent process inhibited by wortmannin, indicating that the transport takes place via the transcytosis pathway. Analyses of the naturally occurring milk mixture of full-length and N-terminal fragments showed that the N-terminal fragments of OPN bound intestinal cells most effectively and that the fragments were transported across the intestinal membrane models. This suggests that proteolytic processing of OPN increases its biological activity after ingestion.
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spelling pubmed-100452682023-03-29 Naturally Occurring N-Terminal Fragments of Bovine Milk Osteopontin Are Transported across Models of the Intestinal Barrier Christensen, Brian Nielsen, Nanna R. Sørensen, Marie R. Jacobsen, Lotte N. Ostenfeld, Marie S. Sørensen, Esben S. Biomedicines Article Osteopontin (OPN) is a bioactive integrin-binding protein found in high concentrations in milk, where it is present both as a full-length protein and as several N-terminally derived fragments. OPN resists gastric digestion, and via interaction with receptors in the gut or by crossing the intestinal barrier into circulation, ingested milk OPN may influence physiological processes. The aim of this study was to investigate OPN interaction with intestinal cells and its transport across models of the intestinal barrier. Immunodetection of OPN incubated with Caco-2 cells at 4 °C and 37 °C showed that OPN binds to the intestinal cells, but it is not internalised. Transepithelial transport was studied using mono- and co-cultures of Caco-2 cells and mucus-producing HT29-MTX cells in transwell membranes. OPN was shown to cross the barrier models in a time-, temperature-, and energy-dependent process inhibited by wortmannin, indicating that the transport takes place via the transcytosis pathway. Analyses of the naturally occurring milk mixture of full-length and N-terminal fragments showed that the N-terminal fragments of OPN bound intestinal cells most effectively and that the fragments were transported across the intestinal membrane models. This suggests that proteolytic processing of OPN increases its biological activity after ingestion. MDPI 2023-03-14 /pmc/articles/PMC10045268/ /pubmed/36979872 http://dx.doi.org/10.3390/biomedicines11030893 Text en © 2023 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Christensen, Brian
Nielsen, Nanna R.
Sørensen, Marie R.
Jacobsen, Lotte N.
Ostenfeld, Marie S.
Sørensen, Esben S.
Naturally Occurring N-Terminal Fragments of Bovine Milk Osteopontin Are Transported across Models of the Intestinal Barrier
title Naturally Occurring N-Terminal Fragments of Bovine Milk Osteopontin Are Transported across Models of the Intestinal Barrier
title_full Naturally Occurring N-Terminal Fragments of Bovine Milk Osteopontin Are Transported across Models of the Intestinal Barrier
title_fullStr Naturally Occurring N-Terminal Fragments of Bovine Milk Osteopontin Are Transported across Models of the Intestinal Barrier
title_full_unstemmed Naturally Occurring N-Terminal Fragments of Bovine Milk Osteopontin Are Transported across Models of the Intestinal Barrier
title_short Naturally Occurring N-Terminal Fragments of Bovine Milk Osteopontin Are Transported across Models of the Intestinal Barrier
title_sort naturally occurring n-terminal fragments of bovine milk osteopontin are transported across models of the intestinal barrier
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10045268/
https://www.ncbi.nlm.nih.gov/pubmed/36979872
http://dx.doi.org/10.3390/biomedicines11030893
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