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Sorokina L, Solberg NT, Koga S, Rønning SB, Afseth NK, Wilson SR, Rieder A, Wubshet SG. In vitro gastrointestinal stability and intestinal absorption of ACE-1 and DPP4 inhibitory peptides from poultry by-product hydrolysates. Food Funct 2024; 15:7364-7374. [PMID: 38912915 DOI: 10.1039/d4fo01214c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/25/2024]
Abstract
Bioactive peptides derived from food are promising health-promoting ingredients that can be used in functional foods and nutraceutical formulations. In addition to the potency towards the selected therapeutic target, the bioavailability of bioactive peptides is a major factor regarding clinical efficacy. We have previously shown that a low molecular weight peptide fraction (LMWPF) from poultry by-product hydrolysates possesses angiotensin-1-converting enzyme (ACE-1) and dipeptidyl-peptidase 4 (DPP4) inhibitory activities. The present study aimed to investigate the bioavailability of the bioactive peptides in the LMWPF. Prior to the investigation of bioavailability, a dipeptide YA was identified from this fraction as a dual inhibitor of ACE-1 and DPP4. Gastrointestinal (GI) stability and intestinal absorption of the bioactive peptides (i.e., YA as well as two previously reported bioactive dipeptides (VL and IY)) in the LMWPF were evaluated using the INFOGEST static in vitro digestion model and intestinal Caco-2 cell monolayer, respectively. Analysis of peptides after in vitro digestion confirmed that the dipeptides were resistant to the simulated GI conditions. After 4 hours of incubation, the concentration of the peptide from the apical side of the Caco-2 cell monolayer showed a significant decrease. However, the corresponding absorbed peptides were not detected on the basolateral side, suggesting that the peptides were not transported across the intestinal monolayer but rather taken up or metabolized by the Caco2 cells. Furthermore, when analyzing the gene expression of the Caco-2 cells upon peptide stimulation, a down-regulation of peptide transporters, the transcription factor CDX2, and the tight junction protein-1 (TJP1) was observed, suggesting the specific effects of the peptides on the Caco-2 cells. The study demonstrated that bioactive dipeptides found in the LMWPF were stable through in vitro GI digestion; however, the overall bioavailability may be hindered by inadequate uptake across the intestinal barrier.
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Affiliation(s)
- Liudmila Sorokina
- Nofima AS-Norwegian Institute of Food, Fisheries and Aquaculture Research, PB 210, N-1431 Ås, Norway.
- Department of Chemistry, University of Oslo, Oslo, Norway
| | - Nina Therese Solberg
- Nofima AS-Norwegian Institute of Food, Fisheries and Aquaculture Research, PB 210, N-1431 Ås, Norway.
| | - Shiori Koga
- Nofima AS-Norwegian Institute of Food, Fisheries and Aquaculture Research, PB 210, N-1431 Ås, Norway.
| | - Sissel Beate Rønning
- Nofima AS-Norwegian Institute of Food, Fisheries and Aquaculture Research, PB 210, N-1431 Ås, Norway.
| | - Nils Kristian Afseth
- Nofima AS-Norwegian Institute of Food, Fisheries and Aquaculture Research, PB 210, N-1431 Ås, Norway.
| | | | - Anne Rieder
- Nofima AS-Norwegian Institute of Food, Fisheries and Aquaculture Research, PB 210, N-1431 Ås, Norway.
| | - Sileshi Gizachew Wubshet
- Nofima AS-Norwegian Institute of Food, Fisheries and Aquaculture Research, PB 210, N-1431 Ås, Norway.
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2
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Kirupananthan D, Bertolo RF, Brunton JA. Lysine Dipeptide Enhances Gut Structure and Whole-Body Protein Synthesis in Neonatal Piglets with Intestinal Atrophy. J Nutr 2022; 152:1843-1850. [PMID: 35481706 DOI: 10.1093/jn/nxac095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Revised: 03/28/2022] [Accepted: 04/21/2022] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Parenteral nutrition (PN) is often a necessity for preterm infants; however, prolonged PN leads to gut atrophy, weakened gut barrier function, and a higher risk of intestinal infections. Peptide transporter-1 (PepT1) is a di- or tripeptide transporter in the gut and, unlike other nutrient transporters, its activity is preserved with the onset of intestinal atrophy from PN. As such, enteral amino acids in the form of dipeptides may be more bioavailable than free amino acids when atrophy is present. OBJECTIVES In Yucatan miniature piglets with PN-induced intestinal atrophy, we sought to determine the structural and functional effects of enteral refeeding with lysine as a dipeptide, compared to free L-lysine. METHODS Piglets aged 7-8 days were PN-fed for 4 days to induce intestinal atrophy, then were refed with enteral diets with equimolar lysine supplied as lysyl-lysine (Lys-Lys; n = 7), free lysine (n = 7), or Lys-Lys with glycyl-sarcosine (n = 6; to determine whether competitive inhibition of Lys-Lys uptake would abolish PepT1-mediated effects). The diets provided lysine at 75% of the requirement and were gastrically delivered for a total of 18 hours. Whole-body and tissue-specific protein synthesis, as well as indices for gut structure and barrier function, were measured. RESULTS The villus height, mucosal weight, and free lysine concentration were higher in the Lys-Lys group compared to the other 2 groups (P < 0.05). Lysyl-lysine led to greater whole-body protein synthesis compared to free lysine (P < 0.05). Mucosal myeloperoxidase activity was lower in the Lys-Lys group (P < 0.05), suggesting less inflammation. The inclusion of glycyl-sarcosine with Lys-Lys abolished the dipeptide effects on whole-body and tissue-specific protein synthesis (P < 0.05), suggesting that improved lysine availability was mediated by PepT1. CONCLUSIONS Improved intestinal structure and whole-body protein synthesis suggests that feeding strategies designed to exploit PepT1 may help to avoid adverse effects when enteral nutrition is reintroduced into the compromised guts of neonatal piglets.
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Affiliation(s)
| | - Robert F Bertolo
- Department of Biochemistry, Memorial University of Newfoundland, St. John's, NL, Canada
| | - Janet A Brunton
- Department of Biochemistry, Memorial University of Newfoundland, St. John's, NL, Canada
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3
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Khavinson V, Linkova N, Kozhevnikova E, Dyatlova A, Petukhov M. Transport of Biologically Active Ultrashort Peptides Using POT and LAT Carriers. Int J Mol Sci 2022; 23:ijms23147733. [PMID: 35887081 PMCID: PMC9323678 DOI: 10.3390/ijms23147733] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2022] [Revised: 07/11/2022] [Accepted: 07/12/2022] [Indexed: 01/27/2023] Open
Abstract
Ultrashort peptides (USPs), consisting of 2–7 amino-acid residues, are a group of signaling molecules that regulate gene expression and protein synthesis under normal conditions in various diseases and ageing. USPs serve as a basis for the development of drugs with a targeted mechanism of action. The purpose of this review is to systematize the available data on USP transport involving POT and LAT transporters in various organs and tissues under normal, pathological and ageing conditions. The carriers of the POT family (PEPT1, PEPT2, PHT1, PHT2) transport predominantly di- and tripeptides into the cell. Methods of molecular modeling and physicochemistry have demonstrated the ability of LAT1 to transfer not only amino acids but also some di- and tripeptides into the cell and out of it. LAT1 and 2 are involved in the regulation of the antioxidant, endocrine, immune and nervous systems’ functions. Analysis of the above data allows us to conclude that, depending on their structure, di- and tripeptides can be transported into the cells of various tissues by POT and LAT transporters. This mechanism is likely to underlie the tissue specificity of peptides, their geroprotective action and effectiveness in the case of neuroimmunoendocrine system disorders.
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Affiliation(s)
- Vladimir Khavinson
- Department of Biogerontology, Saint Petersburg Institute of Bioregulation and Gerontology, 197110 Saint Petersburg, Russia; (N.L.); (E.K.); (A.D.)
- Group of Peptide Regulation of Aging, Pavlov Institute of Physiology of Russian Academy of Sciences, 199034 Saint Petersburg, Russia
- Correspondence: or ; Tel.: +7-(921)-9110800
| | - Natalia Linkova
- Department of Biogerontology, Saint Petersburg Institute of Bioregulation and Gerontology, 197110 Saint Petersburg, Russia; (N.L.); (E.K.); (A.D.)
- The Laboratory “Problems of Aging”, Belgorod National Research University, 308015 Belgorod, Russia
| | - Ekaterina Kozhevnikova
- Department of Biogerontology, Saint Petersburg Institute of Bioregulation and Gerontology, 197110 Saint Petersburg, Russia; (N.L.); (E.K.); (A.D.)
| | - Anastasiia Dyatlova
- Department of Biogerontology, Saint Petersburg Institute of Bioregulation and Gerontology, 197110 Saint Petersburg, Russia; (N.L.); (E.K.); (A.D.)
| | - Mikhael Petukhov
- Petersburg Nuclear Physics Institute Named after B.P. Konstantinov, NRC “Kurchatov Institute”, 188300 Gatchina, Russia;
- Peter the Great St. Petersburg Group of Biophysics, Higher Engineering and Technical School, Peter the Great St. Petersburg Polytechnic University, 195251 Saint Petersburg, Russia
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4
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Wang X, Chen Y, Wang Y, Wang B, Zhang J, Jian X. Expression, Regulation, and Role of an Oligopeptide Transporter: PEPT1 in Tumors. Curr Med Chem 2022; 29:1596-1605. [PMID: 35546503 DOI: 10.2174/0929867328666210707170214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 04/04/2021] [Accepted: 04/21/2021] [Indexed: 11/22/2022]
Abstract
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PEPT1 is a vital member of the proton-dependent oligopeptide transporters
family (POTs). Many studies have confirmed that PEPT1 plays a critical role in the absorption
of dipeptides, tripeptides, and pseudopeptides in the intestinal tract. In recent
years, several studies have found that PEPT1 is highly expressed in malignant tumor tissues
and cells. The abnormal expression of PEPT1 in tumors may be closely related to the
progress of tumors, and hence, could be considered as a potential molecular biomarker for
the diagnosis, treatment, and prognosis in malignant tumors. Furthermore, PEPT1 can be
used to mediate the targeted delivery of anti-tumor drugs. Herein, the expression, regulation,
and role of PEPT1 in tumors in recent years have been reviewed.
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Affiliation(s)
- Xi Wang
- Department of Gastroenterology and Hepatology, Tianjin Medical University General Hospital, Tianjin Institute
of Digestive Disease, Tianjin 300052, China
- Tianjin Baodi Hospital/Baodi Clinical College of Tianjin
Medical University, Tianjin 300052, China
| | - Yiming Chen
- Department of Gastroenterology and Hepatology, Tianjin Medical University General Hospital, Tianjin Institute
of Digestive Disease, Tianjin 300052, China
| | - Yongjuan Wang
- Department of Gastroenterology and Hepatology, The Second
Affiliated Hospital of Hebei Medical University, Hebei, China
| | - Bangmao Wang
- Department of Gastroenterology and Hepatology, Tianjin Medical University General Hospital, Tianjin Institute
of Digestive Disease, Tianjin 300052, China
| | - Jie Zhang
- Department of Gastroenterology and Hepatology, Tianjin Medical University General Hospital, Tianjin Institute
of Digestive Disease, Tianjin 300052, China
| | - Xu Jian
- Central Laboratory, Tianjin Medical University
General Hospital, Tianjin, 300052, China
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5
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Brezas A, Kumar V, Overturf K, Hardy RW. Dietary amino acid supplementation affects temporal expression of amino acid transporters and metabolic genes in selected and commercial strains of rainbow trout (Oncorhynchus mykiss). Comp Biochem Physiol B Biochem Mol Biol 2021; 255:110589. [DOI: 10.1016/j.cbpb.2021.110589] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 02/09/2021] [Accepted: 02/23/2021] [Indexed: 02/07/2023]
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6
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Tokutake Y, Taciak M, Sato K, Toyomizu M, Kikusato M. Effect of dipeptide on intestinal peptide transporter 1 gene expression: An evaluation using primary cultured chicken intestinal epithelial cells. Anim Sci J 2021; 92:e13604. [PMID: 34309968 PMCID: PMC9285489 DOI: 10.1111/asj.13604] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 06/20/2021] [Accepted: 06/28/2021] [Indexed: 12/21/2022]
Abstract
Peptide transporter 1 (PepT1) is a transporter responsible for absorbing dipeptide and tripeptide in enterocytes and is upregulated by dipeptide in mammals. It has not been certain whether intestinal PepT1 expression is responsive to dipeptides in chickens because of the lack of in vitro study using the cultured enterocytes. This study established a primary culture model of chicken intestinal epithelial cells (IECs) in two‐dimensional monolayer culture using collagen gel by which the response of chicken PepT1 gene expression to dipeptide stimuli was evaluated. The cultured chicken IECs showed the epithelial‐like morphology attached in a patch‐manner and exhibited positive expression of cytokeratin and epithelial cadherin, specific marker proteins of epithelial cells. Moreover, the chicken IECs exhibited the gene expression of intestinal cell type‐specific marker, villin1, mucin 2, and chromogranin A, suggesting that the cultured IECs were composed of enterocytes as well as goblet and enteroendocrine cells. PepT1 gene expression was significantly upregulated by synthetic dipeptide, glycyl‐l‐glutamine, in the cultured IECs. From the results, we herein suggested that dipeptide is a factor upregulating PepT1 gene expression in chicken IECs.
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Affiliation(s)
- Yukako Tokutake
- Animal Nutrition, Life Sciences, Graduate School of Agricultural Science, Tohoku University, Sendai, Japan
| | - Marcin Taciak
- Animal Nutrition, Life Sciences, Graduate School of Agricultural Science, Tohoku University, Sendai, Japan.,The Kielanowski Institute of Animal Physiology and Nutrition, Polish Academy of Sciences, Jabłonna, Poland
| | - Kan Sato
- Animal Nutrition, Life Sciences, Graduate School of Agricultural Science, Tohoku University, Sendai, Japan
| | - Masaaki Toyomizu
- Animal Nutrition, Life Sciences, Graduate School of Agricultural Science, Tohoku University, Sendai, Japan
| | - Motoi Kikusato
- Animal Nutrition, Life Sciences, Graduate School of Agricultural Science, Tohoku University, Sendai, Japan
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7
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Rapid and Sensitive Quantification of Intracellular Glycyl-Sarcosine for Semi-High-Throughput Screening for Inhibitors of PEPT-1. Pharmaceutics 2021; 13:pharmaceutics13071019. [PMID: 34371711 PMCID: PMC8309108 DOI: 10.3390/pharmaceutics13071019] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 06/28/2021] [Accepted: 07/01/2021] [Indexed: 12/23/2022] Open
Abstract
The peptide transporter PEPT-1 (SLC15A1) plays a major role in nutritional supply with amino acids by mediating the intestinal influx of dipeptides and tripeptides generated during food digestion. Its role in the uptake of small bioactive peptides and various therapeutics makes it an important target for the investigation of the systemic absorption of small peptide-like active compounds and prodrug strategies of poorly absorbed therapeutics. The dipeptide glycyl-sarcosine (Gly-Sar), which comprises an N-methylated peptide bond that increases stability against enzymatic degradation, is widely utilized for studying PEPT-1-mediated transport. To support experiments on PEPT-1 inhibitor screening to identify potential substrates, we developed a highly sensitive Gly-Sar quantification assay for Caco-2 cell lysates with a dynamic range of 0.1 to 1000 ng/mL (lower limit of quantification 0.68 nM) in 50 µL of cell lysate. The assay was validated following the applicable recommendations for bioanalytic method validation of the FDA and EMA. Sample preparation and quantification were established in 96-well cell culture plates that were also used for the cellular uptake studies, resulting in a rapid and robust screening assay for PEPT-1 inhibitors. This sample preparation principle, combined with the high sensitivity of the UPLC-MS/MS quantification, is suitable for screening assays for PEPT-1 inhibitors and substrates in high-throughput formats and holds the potential for automation. Applicability was demonstrated by IC50 determinations of the known PEPT-1 inhibitor losartan, the known substrates glycyl-proline (Gly-Pro), and valaciclovir, the prodrug of aciclovir, which itself is no substrate of PEPT-1 and consequently showed no inhibition in our assay.
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8
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Murata Y, Yoshida M, Sakamoto N, Morimoto S, Watanabe T, Namba K. Iron uptake mediated by the plant-derived chelator nicotianamine in the small intestine. J Biol Chem 2020; 296:100195. [PMID: 33334885 PMCID: PMC7948497 DOI: 10.1074/jbc.ra120.015861] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 11/28/2020] [Accepted: 12/14/2020] [Indexed: 11/06/2022] Open
Abstract
Iron is an essential metal for all living organisms that is absorbed in the intestinal cells as a heme-chelated or free form. It is unclear how important plant-derived chelators, such as nicotianamine (NA), an organic small molecule that is ubiquitous in crops, vegetables, and various other foods, contribute to iron bioavailability in mammals. We performed electrophysiological assays with Xenopus laevis oocytes and radioactive tracer experiments with Caco-2 cells. The findings revealed that the proton-coupled amino acid transporter SLC36A1 (PAT1) transports iron in the form of NA-Fe (II) complex in vitro. Decreased expression of hPAT1 by RNA interference in Caco-2 cells reduced the uptake of NA-59Fe (II) complex. The uptake of inorganic 59Fe (II) was relatively unaffected. These results imply that PAT1 transports iron as a NA-Fe (II) complex. The rate of 59Fe absorption in the spleen, liver, and kidney was higher when mice were orally administered NA-59Fe (II) compared with free 59Fe (II). The profile of site-specific PAT1 expression in the mouse intestine coincided with those of NA and iron contents, which were the highest in the proximal jejunum. Orally administered NA-59Fe (II) complex in mice was detected in the proximal jejunum by thin layer chromatography. In contrast, much less 59Fe (or NA) was detected in the duodenum, where the divalent metal transporter SLC11A2 (DMT1) absorbs free Fe (II). The collective results revealed the role of PAT1 in NA-Fe (II) absorption in the intestine and potential implication of NA in iron uptake in mammals.
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Affiliation(s)
- Yoshiko Murata
- Bioorganic Research Institute, Suntory Foundation for Life Sciences, Soraku-gun, Kyoto, Japan.
| | - Masami Yoshida
- Bioorganic Research Institute, Suntory Foundation for Life Sciences, Soraku-gun, Kyoto, Japan
| | - Naho Sakamoto
- Bioorganic Research Institute, Suntory Foundation for Life Sciences, Soraku-gun, Kyoto, Japan
| | - Shiho Morimoto
- Bioorganic Research Institute, Suntory Foundation for Life Sciences, Soraku-gun, Kyoto, Japan
| | - Takehiro Watanabe
- Bioorganic Research Institute, Suntory Foundation for Life Sciences, Soraku-gun, Kyoto, Japan
| | - Kosuke Namba
- Graduate School of Pharmaceutical Science, Tokushima University, Tokushima, Japan
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9
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Emadinia A, Toghyani M, Foroozandeh AD, Tabeidian SA, Ostadsharif M. Effect of protein reduction and valine levels on growth performance, carcass characteristics, protein digestibility and SLC71 gene expression in Japanese quail. Livest Sci 2020. [DOI: 10.1016/j.livsci.2020.103998] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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10
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Effects on the Caco-2 Cells of a Hypoglycemic Protein from Lupin Seeds in a Solution and Adsorbed on Polystyrene Nanoparticles to Mimic a Complex Food Matrix. Biomolecules 2019; 9:biom9100606. [PMID: 31615064 PMCID: PMC6843813 DOI: 10.3390/biom9100606] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 10/10/2019] [Accepted: 10/13/2019] [Indexed: 12/31/2022] Open
Abstract
The search for bioactivities influencing the human wellbeing of food proteins and peptides is a topic of broad and current interest. γ-Conglutin (γC) is a lupin seed protein drawing remarkable pharmacological and/or nutraceutical interest, as it is able to reduce hyperglycemia in humans and animal models. The present work deepens our investigations to understand the molecular basis of the in vitro effects of γC by testing the possible metabolic effects on cultivated Caco-2 cells. γC and its derived peptides (obtained via simulated gastrointestinal digestion) did not influence the cell viability at incubation times up to 24 h. The incubation of cells with native or digested γC caused no detectable inflammation processes mediated by Nuclear Factor kappa B (NFκB). We checked if treatment with γC or its derived peptides can elicit the expression of two peptide transporters (Pept-1 and Htp-1) by using an RT-qPCR approach. Native γC caused the halving of Pept-1 expression compared to untreated cells, but this effect disappeared when γC was digested. Either native γC or γC peptides reduced the expression levels of Hpt-1. Finally, this work also sheds light on the possible structural modifications of γC that may occur in the gastrointestinal tract, using an in vitro simulated dispersed system with polystyrene nanoparticles (NPs).
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11
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Martin M, Hagemann D, Nguyen TT, Schwarz L, Khedr S, Moskopp ML, Henle T, Deussen A. Plasma concentrations and ACE-inhibitory effects of tryptophan-containing peptides from whey protein hydrolysate in healthy volunteers. Eur J Nutr 2019; 59:1135-1147. [DOI: 10.1007/s00394-019-01974-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Accepted: 04/17/2019] [Indexed: 12/19/2022]
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Abstract
The regulation of energy and glucose balance contributes to whole-body metabolic homeostasis, and such metabolic regulation is disrupted in obesity and diabetes. Metabolic homeostasis is orchestrated partly in response to nutrient and vagal-dependent gut-initiated functions. Specifically, the sensory and motor fibres of the vagus nerve transmit intestinal signals to the central nervous system and exert biological and physiological responses. In the past decade, the understanding of the regulation of vagal afferent signals and of the associated metabolic effect on whole-body energy and glucose balance has progressed. This Review highlights the contributions made to the understanding of the vagal afferent system and examines the integrative role of the vagal afferent in gastrointestinal regulation of appetite and glucose homeostasis. Investigating the integrative and metabolic role of vagal afferent signalling represents a potential strategy to discover novel therapeutic targets to restore energy and glucose balance in diabetes and obesity.
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13
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Viennois E, Pujada A, Zen J, Merlin D. Function, Regulation, and Pathophysiological Relevance of the POT Superfamily, Specifically PepT1 in Inflammatory Bowel Disease. Compr Physiol 2018; 8:731-760. [PMID: 29687900 DOI: 10.1002/cphy.c170032] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Mammalian members of the proton-coupled oligopeptide transporter family are integral membrane proteins that mediate the cellular uptake of di/tripeptides and peptide-like drugs and couple substrate translocation to the movement of H+ , with the transmembrane electrochemical proton gradient providing the driving force. Peptide transporters are responsible for the (re)absorption of dietary and/or bacterial di- and tripeptides in the intestine and kidney and maintaining homeostasis of neuropeptides in the brain. These proteins additionally contribute to absorption of a number of pharmacologically important compounds. In this overview article, we have provided updated information on the structure, function, expression, localization, and activities of PepT1 (SLC15A1), PepT2 (SLC15A2), PhT1 (SLC15A4), and PhT2 (SLC15A3). Peptide transporters, in particular, PepT1 are discussed as drug-delivery systems in addition to their implications in health and disease. Particular emphasis has been placed on the involvement of PepT1 in the physiopathology of the gastrointestinal tract, specifically, its role in inflammatory bowel diseases. © 2018 American Physiological Society. Compr Physiol 8:731-760, 2018.
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Affiliation(s)
- Emilie Viennois
- Institute for Biomedical Sciences, Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, Georgia, USA
| | - Adani Pujada
- Institute for Biomedical Sciences, Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, Georgia, USA
| | - Jane Zen
- Institute for Biomedical Sciences, Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, Georgia, USA
| | - Didier Merlin
- Institute for Biomedical Sciences, Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, Georgia, USA.,Veterans Affairs Medical Center, Decatur, Georgia, USA
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Olukosi OA, Xiao W, Jia J. Peptide supplementation to nutrient-adequate diets enhanced internal egg quality during storage in hens at peak production. JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE 2018; 98:1850-1855. [PMID: 28885687 DOI: 10.1002/jsfa.8661] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Revised: 08/19/2017] [Accepted: 09/03/2017] [Indexed: 06/07/2023]
Abstract
BACKGROUND There is paucity of information on the use of dietary peptides in laying hens and its effects on egg production and quality. In the current study, peptide from enzymatic hydrolysis of soybean protein was incorporated into laying hens' diets to investigate its effect on egg production and internal egg quality. RESULTS There were no treatment effects on egg production (average hen day production was 96%) during the experiment. Final body weight of the hens increased quadratically (P < 0.05) in response to peptide supplementation. There were no significant effects of peptide supplementation on internal egg quality of the fresh eggs. Peptide supplementation tended to increase yolk colour (P < 0.10) in eggs collected at 4 weeks of the study and stored at room temperature for 14 days. For the eggs collected at 8 weeks of the experiment and stored at room temperature for 14 days, peptide supplementation linearly increased (P < 0.05) albumen height, Haugh unit and yolk index but linearly decreased (P < 0.01) yolk width. CONCLUSION Peptide supplementation to laying hens at peak production, receiving diets meeting their nutrient requirement, did not improve hen production but positively helped to maintain hens' body weight and egg quality during storage. © 2017 Society of Chemical Industry.
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Affiliation(s)
- Oluyinka A Olukosi
- Monogastric Science Research Centre, Scotland's Rural College, Edinburgh, UK
| | | | - Jing Jia
- Mytech Biotech Co. Ltd, Chengdu, PR China
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15
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Wang CY, Liu S, Xie XN, Tan ZR. Regulation profile of the intestinal peptide transporter 1 (PepT1). DRUG DESIGN DEVELOPMENT AND THERAPY 2017; 11:3511-3517. [PMID: 29263649 PMCID: PMC5726373 DOI: 10.2147/dddt.s151725] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The intestinal peptide transporter 1 (PepT1) was first identified in 1994. It plays a crucial role in the absorption of small peptides including not only >400 different dipeptides and 8,000 tripeptides digested from dietary proteins but also a repertoire of structurally related compounds and drugs. Owing to its critical role in the bioavailability of peptide-like drugs, such as the anti-cancer agents and anti-virus drug, PepT1 is increasingly becoming a striking prodrug-designing target. Therefore, the understanding of PepT1 gene regulation is of great importance both for dietary adaptation and for clinical drug treatment. After decades of research, it has been recognized that PepT1 could be regulated at the transcriptional and post-transcriptional levels by numerous factors. Therefore, the present review intends to summarize the progress made in the regulation of PepT1 and provide insights into the PepT1's potential in clinical aspects of nutritional and drug therapies.
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Affiliation(s)
- Chun-Yang Wang
- Department of Clinical Pharmacology, Xiangya Hospital, Xiangya School of Medicine, Central South University.,Hunan Key Laboratory of Pharmacogenetics, Institute of Clinical Pharmacology, Central South University, Changsha, Hunan, People's Republic of China
| | - Shu Liu
- Department of Clinical Pharmacology, Xiangya Hospital, Xiangya School of Medicine, Central South University.,Hunan Key Laboratory of Pharmacogenetics, Institute of Clinical Pharmacology, Central South University, Changsha, Hunan, People's Republic of China
| | - Xiao-Nv Xie
- Department of Clinical Pharmacology, Xiangya Hospital, Xiangya School of Medicine, Central South University.,Hunan Key Laboratory of Pharmacogenetics, Institute of Clinical Pharmacology, Central South University, Changsha, Hunan, People's Republic of China
| | - Zhi-Rong Tan
- Department of Clinical Pharmacology, Xiangya Hospital, Xiangya School of Medicine, Central South University.,Hunan Key Laboratory of Pharmacogenetics, Institute of Clinical Pharmacology, Central South University, Changsha, Hunan, People's Republic of China
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Osmanyan AK, Ghazi Harsini S, Mahdavi R, Fisinin VI, Arkhipova AL, Glazko TT, Kovalchuk SN, Kosovsky GY. Intestinal amino acid and peptide transporters in broiler are modulated by dietary amino acids and protein. Amino Acids 2017; 50:353-357. [DOI: 10.1007/s00726-017-2510-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2017] [Accepted: 11/04/2017] [Indexed: 01/05/2023]
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Pak YA, Long AJ, Annes WF, Witcher JW, Knadler MP, Ayan-Oshodi MA, Mitchell MI, Leese P, Hillgren KM. In Vitro and Clinical Evaluations of the Drug-Drug Interaction Potential of a Metabotropic Glutamate 2/3 Receptor Agonist Prodrug with Intestinal Peptide Transporter 1. Drug Metab Dispos 2016; 45:137-144. [PMID: 27895114 PMCID: PMC5267515 DOI: 10.1124/dmd.116.071118] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Accepted: 11/21/2016] [Indexed: 01/15/2023] Open
Abstract
Despite peptide transporter 1 (PEPT1) being responsible for the bioavailability for a variety of drugs, there has been little study of its potential involvement in drug-drug interactions. Pomaglumetad methionil, a metabotropic glutamate 2/3 receptor agonist prodrug, utilizes PEPT1 to enhance absorption and bioavailability. In vitro studies were conducted to guide the decision to conduct a clinical drug interaction study and to inform the clinical study design. In vitro investigations determined the prodrug (LY2140023 monohydrate) is a substrate of PEPT1 with Km value of approximately 30 µM, whereas the active moiety (LY404039) is not a PEPT1 substrate. In addition, among the eight known PEPT1 substrates evaluated in vitro, valacyclovir was the most potent inhibitor (IC50 = 0.46 mM) of PEPT1-mediated uptake of the prodrug. Therefore, a clinical drug interaction study was conducted to evaluate the potential interaction between the prodrug and valacyclovir in healthy subjects. No effect of coadministration was observed on the pharmacokinetics of the prodrug, valacyclovir, or either of their active moieties. Although in vitro studies showed potential for the prodrug and valacyclovir interaction via PEPT1, an in vivo study showed no interaction between these two drugs. PEPT1 does not appear to easily saturate because of its high capacity and expression in the intestine. Thus, a clinical interaction at PEPT1 is unlikely even with a compound with high affinity for the transporter.
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Affiliation(s)
- Y Anne Pak
- Eli Lilly and Company, Lilly Corporate Center, Indianapolis, Indiana (Y.A.P., A.J.L.,W.F.A., J.W.W., M.P.K., M.A.A.-O., M.I.M., K.M.H.); and Quintiles Transnational, Clinical Pharmacology, Overland Park, Kansas (P.L.)
| | - Amanda J Long
- Eli Lilly and Company, Lilly Corporate Center, Indianapolis, Indiana (Y.A.P., A.J.L.,W.F.A., J.W.W., M.P.K., M.A.A.-O., M.I.M., K.M.H.); and Quintiles Transnational, Clinical Pharmacology, Overland Park, Kansas (P.L.)
| | - William F Annes
- Eli Lilly and Company, Lilly Corporate Center, Indianapolis, Indiana (Y.A.P., A.J.L.,W.F.A., J.W.W., M.P.K., M.A.A.-O., M.I.M., K.M.H.); and Quintiles Transnational, Clinical Pharmacology, Overland Park, Kansas (P.L.)
| | - Jennifer W Witcher
- Eli Lilly and Company, Lilly Corporate Center, Indianapolis, Indiana (Y.A.P., A.J.L.,W.F.A., J.W.W., M.P.K., M.A.A.-O., M.I.M., K.M.H.); and Quintiles Transnational, Clinical Pharmacology, Overland Park, Kansas (P.L.)
| | - Mary Pat Knadler
- Eli Lilly and Company, Lilly Corporate Center, Indianapolis, Indiana (Y.A.P., A.J.L.,W.F.A., J.W.W., M.P.K., M.A.A.-O., M.I.M., K.M.H.); and Quintiles Transnational, Clinical Pharmacology, Overland Park, Kansas (P.L.)
| | - Mosun A Ayan-Oshodi
- Eli Lilly and Company, Lilly Corporate Center, Indianapolis, Indiana (Y.A.P., A.J.L.,W.F.A., J.W.W., M.P.K., M.A.A.-O., M.I.M., K.M.H.); and Quintiles Transnational, Clinical Pharmacology, Overland Park, Kansas (P.L.)
| | - Malcolm I Mitchell
- Eli Lilly and Company, Lilly Corporate Center, Indianapolis, Indiana (Y.A.P., A.J.L.,W.F.A., J.W.W., M.P.K., M.A.A.-O., M.I.M., K.M.H.); and Quintiles Transnational, Clinical Pharmacology, Overland Park, Kansas (P.L.)
| | - Phillip Leese
- Eli Lilly and Company, Lilly Corporate Center, Indianapolis, Indiana (Y.A.P., A.J.L.,W.F.A., J.W.W., M.P.K., M.A.A.-O., M.I.M., K.M.H.); and Quintiles Transnational, Clinical Pharmacology, Overland Park, Kansas (P.L.)
| | - Kathleen M Hillgren
- Eli Lilly and Company, Lilly Corporate Center, Indianapolis, Indiana (Y.A.P., A.J.L.,W.F.A., J.W.W., M.P.K., M.A.A.-O., M.I.M., K.M.H.); and Quintiles Transnational, Clinical Pharmacology, Overland Park, Kansas (P.L.)
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Di- and tripeptide transport in vertebrates: the contribution of teleost fish models. J Comp Physiol B 2016; 187:395-462. [PMID: 27803975 DOI: 10.1007/s00360-016-1044-7] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Revised: 10/12/2016] [Accepted: 10/20/2016] [Indexed: 02/06/2023]
Abstract
Solute Carrier 15 (SLC15) family, alias H+-coupled oligopeptide cotransporter family, is a group of membrane transporters known for their role in the cellular uptake of di- and tripeptides (di/tripeptides) and peptide-like molecules. Of its members, SLC15A1 (PEPT1) chiefly mediates intestinal absorption of luminal di/tripeptides from dietary protein digestion, while SLC15A2 (PEPT2) mainly allows renal tubular reabsorption of di/tripeptides from ultrafiltration, SLC15A3 (PHT2) and SLC15A4 (PHT1) possibly interact with di/tripeptides and histidine in certain immune cells, and SLC15A5 has unknown function. Our understanding of this family in vertebrates has steadily increased, also due to the surge of genomic-to-functional information from 'non-conventional' animal models, livestock, poultry, and aquaculture fish species. Here, we review the literature on the SLC15 transporters in teleost fish with emphasis on SLC15A1 (PEPT1), one of the solute carriers better studied amongst teleost fish because of its relevance in animal nutrition. We report on the operativity of the transporter, the molecular diversity, and multiplicity of structural-functional solutions of the teleost fish orthologs with respect to higher vertebrates, its relevance at the intersection of the alimentary and osmoregulative functions of the gut, its response under various physiological states and dietary solicitations, and its possible involvement in examples of total body plasticity, such as growth and compensatory growth. By a comparative approach, we also review the few studies in teleost fish on SLC15A2 (PEPT2), SLC15A4 (PHT1), and SLC15A3 (PHT2). By representing the contribution of teleost fish to the knowledge of the physiology of di/tripeptide transport and transporters, we aim to fill the gap between higher and lower vertebrates.
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Nosworthy MG, Dodge ME, Bertolo RF, Brunton JA. Enterally delivered dipeptides improve small intestinal inflammatory status in a piglet model of intestinal resection. Clin Nutr 2016; 35:852-8. [DOI: 10.1016/j.clnu.2015.05.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Revised: 04/23/2015] [Accepted: 05/24/2015] [Indexed: 11/24/2022]
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Dioscin protects against ANIT–induced cholestasis via regulating Oatps, Mrp2 and Bsep expression in rats. Toxicol Appl Pharmacol 2016; 305:127-135. [DOI: 10.1016/j.taap.2016.06.019] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2016] [Revised: 06/04/2016] [Accepted: 06/13/2016] [Indexed: 12/17/2022]
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Intestinal barrier dysfunction: implications for chronic inflammatory conditions of the bowel. Nutr Res Rev 2016; 29:40-59. [DOI: 10.1017/s0954422416000019] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
AbstractThe intestinal epithelium of adult humans acts as a differentially permeable barrier that separates the potentially harmful contents of the lumen from the underlying tissues. Any dysfunction of this boundary layer that disturbs the homeostatic equilibrium between the internal and external environments may initiate and sustain a biochemical cascade that results in inflammation of the intestine. Key to such dysfunction are genetic, microbial and other environmental factors that, singularly or in combination, result in chronic inflammation that is symptomatic of inflammatory bowel disease (IBD). The aim of the present review is to assess the scientific evidence to support the hypothesis that defective transepithelial transport mechanisms and the heightened absorption of intact antigenic proinflammatory oligopeptides are important contributing factors in the pathogenesis of IBD.
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Hu Y, Smith DE. Species differences in the pharmacokinetics of cefadroxil as determined in wildtype and humanized PepT1 mice. Biochem Pharmacol 2016; 107:81-90. [PMID: 26979860 DOI: 10.1016/j.bcp.2016.03.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Accepted: 03/11/2016] [Indexed: 10/22/2022]
Abstract
PepT1 (SLC15A1) is a high-capacity low-affinity transporter that is important in the absorption of digested di/tripeptides from dietary protein in the small intestine. PepT1 is also crucial for the intestinal uptake and absorption of therapeutic agents such as the β-lactam aminocephalosporins and antiviral prodrugs. Species differences, however, have been observed in PepT1-mediated intestinal absorption and pharmacokinetics, thereby, making it more difficult to predict systemic drug exposure. In the present study, we evaluated the in situ intestinal permeability of the PepT1 substrate cefadroxil in wildtype and humanized PepT1 (huPepT1) mice, and the in vivo absorption and disposition of drug after escalating oral doses. The in situ perfusions indicated that cefadroxil had a twofold higher affinity (i.e., twofold lower Km) for jejunal PepT1 in huPepT1 mice, lower but substantial permeability in all regions of the small intestine, and low but measureable permeability in the colon as compared to wildtype animals. The in vivo experiments indicated almost superimposable pharmacokinetic profiles between the two genotypes after intravenous bolus dosing of cefadroxil. In contrast, after oral dose escalation, the systemic exposure of cefadroxil was reduced in huPepT1 mice as compared to wildtype animals. Moreover, the AUC and Cmax versus dose relationships were nonlinear for huPepT1 but not wildtype mice, and similar to that observed from human subjects. In conclusion, our findings indicate that huPepT1 mice may provide a valuable tool in the drug discovery process by better predicting the oral pharmacokinetic profiles of PepT1 substrates in humans.
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Affiliation(s)
- Yongjun Hu
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Michigan, Ann Arbor, MI, USA.
| | - David E Smith
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Michigan, Ann Arbor, MI, USA.
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Chang W, Li J, Zhang S, Zheng A, Yuan J, Cai H, Liu G. Effects of glucocorticoid-induced stress on absorption of glycylsarcosine in jejunum of broilers. Poult Sci 2015; 94:700-5. [DOI: 10.3382/ps/pev041] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
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Hu Y, Xie Y, Wang Y, Chen X, Smith DE. Development and characterization of a novel mouse line humanized for the intestinal peptide transporter PEPT1. Mol Pharm 2014; 11:3737-46. [PMID: 25148225 PMCID: PMC4186676 DOI: 10.1021/mp500497p] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
![]()
The
proton-coupled oligopeptide transporter PEPT1 (SLC15A1) is
abundantly expressed in the small intestine, but not colon, of mammals
and found to mediate the uptake of di/tripeptides and peptide-like
drugs from the intestinal lumen. However, species differences have
been observed in both the expression (and localization) of PEPT1 and
its substrate affinity. With this in mind, the objectives of this
study were to develop a humanized PEPT1 mouse model
(huPEPT1) and to characterize hPEPT1 expression and
functional activity in the intestines. Thus, after generating huPEPT1 mice in animals previously nulled for mouse Pept1, phenotypic, PCR, and immunoblot analyses were performed,
along with in situ single-pass intestinal perfusion
and in vivo oral pharmacokinetic studies with a model
dipeptide, glycylsarcosine (GlySar). Overall, the huPEPT1 mice had normal survival rates, fertility, litter size, gender distribution,
and body weight. There was no obvious behavioral or pathological phenotype.
The mRNA and protein profiles indicated that huPEPT1 mice had substantial PEPT1 expression in all regions of the small
intestine (i.e., duodenum, jejunum, and ileum) along with low but
measurable expression in both proximal and distal segments of the
colon. In agreement with PEPT1 expression, the in situ permeability of GlySar in huPEPT1 mice was similar
to but lower than wildtype animals in small intestine, and greater
than wildtype mice in colon. However, a species difference existed
in the in situ transport kinetics of jejunal PEPT1,
in which the maximal flux and Michaelis constant of GlySar were reduced
7-fold and 2- to 4-fold, respectively, in huPEPT1 compared to wildtype mice. Still, the in vivo function
of intestinal PEPT1 appeared fully restored (compared to Pept1 knockout mice) as indicated by the nearly identical pharmacokinetics
and plasma concentration–time profiles following a 5.0 nmol/g
oral dose of GlySar to huPEPT1 and wildtype mice.
This study reports, for the first time, the development and characterization
of mice humanized for PEPT1. This novel transgenic huPEPT1 mouse model should prove useful in examining the
role, relevance, and regulation of PEPT1 in diet and disease, and
in the drug discovery process.
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Affiliation(s)
- Yongjun Hu
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Michigan , Ann Arbor, Michigan 48109, United States
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A high-protein formula increases colonic peptide transporter 1 activity during neonatal life in low-birth-weight piglets and disturbs barrier function later in life. Br J Nutr 2014; 112:1073-80. [DOI: 10.1017/s0007114514001901] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Dietary peptides are absorbed along the intestine through peptide transporter 1 (PepT-1) which is highly responsive to dietary protein level. PepT-1 is also involved in gut homeostasis, both initiating and resolving inflammation. Low-birth-weight (LBW) neonates are routinely fed a high-protein (HP) formula to enhance growth. However, the influence of this nutritional practice on PepT-1 activity is unknown. Intestinal PepT-1 activity was compared in normal-birth-weight (NBW) and LBW piglets. The effect of HP v. normal-protein (NP) formula feeding on PepT-1 activity and gut homeostasis in LBW piglets was evaluated, during the neonatal period and in adulthood. Flux of cephalexin (CFX) across the tissue mounted in Ussing chambers was used as an indicator of PepT-1 activity. CFX flux was greater in the ileum, but not jejunum or colon, of LBW than NBW piglets during the neonatal period. When LBW piglets were formula-fed, the HP formula increased colonic CFX during the 1st week of life. Later in life, intestinal CFX fluxes and barrier function were similar whether LBW pigs had been fed NP or HP formula. However, colonic permeability of HP- but not NP-fed pigs increased when luminal pH was brought to 6·0. The formyl peptide N-formyl methionyl-leucyl-phenylalanine conferred colonic barrier protection in HP-fed piglets. Heat shock protein 27 levels in the colonic mucosa of HP-fed LBW pigs correlated with the magnitude of response to the acidic challenge. In conclusion, feeding a HP formula enhanced colonic PepT-1 activity in LBW pig neonates and increased sensitivity of the colon to luminal stress in adulthood.
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Abstract
The epithelium of the gastrointestinal tract is one of the most versatile tissues in the organism, responsible for providing a tight barrier between dietary and bacterial antigens and the mucosal and systemic immune system while maintaining efficient digestive and absorptive processes to ensure adequate nutrient and energy supply. Inflammatory bowel diseases (Crohn's disease and ulcerative colitis) are associated with a breakdown of both functions, which in some cases are clearly interrelated. In this updated literature review, we focus on the effects of intestinal inflammation and the associated immune mediators on selected aspects of the transepithelial transport of macronutrients and micronutrients. The mechanisms responsible for nutritional deficiencies are not always clear and could be related to decreased intake, malabsorption, and excess losses. We summarize the known causes of nutrient deficiencies and the mechanism of inflammatory bowel disease-associated diarrhea. We also overview the consequences of impaired epithelial transport, which infrequently transcend its primary purpose to affect the gut microbial ecology and epithelial integrity. Although some of those regulatory mechanisms are relatively well established, more work needs to be done to determine how inflammatory cytokines can alter the transport process of nutrients across the gastrointestinal and renal epithelia.
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Hu Y, Xie Y, Keep RF, Smith DE. Divergent developmental expression and function of the proton-coupled oligopeptide transporters PepT2 and PhT1 in regional brain slices of mouse and rat. J Neurochem 2014; 129:955-65. [PMID: 24548120 DOI: 10.1111/jnc.12687] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2013] [Revised: 01/26/2014] [Accepted: 02/13/2014] [Indexed: 01/22/2023]
Abstract
This study evaluated the developmental gene and protein expression of proton-coupled oligopeptide transporters (POTs: peptide transporter, PepT1 and PepT2; peptide-histidine transporter, PhT1 and PhT2) in different regions of rodent brain, and the age-dependent uptake of a POT substrate, glycylsarcosine (GlySar), in brain slices. Slices were obtained from cerebral cortex, cerebellum and hippocampus of wildtype and PepT2 null mice, and from rats at different ages. Gene and protein expression were determined by real-time PCR and immunoblot analyses. Brain slice uptakes of radiolabeled glycylsarcosine were determined in the absence and presence of excess unlabeled glycylsarcosine or l-histidine, the latter being an inhibitor of PhT1/2 but not PepT1/2. As PepT2 and PhT1 transcripts were abundantly expressed in all three regions of mouse brain, little to no expression was observed for PepT1 and PhT2. PhT1 protein was present in brain regions of adult but not neonatal mice and expression levels increased with age in rats. Glycylsarcosine uptake, inhibition and transporter dominance did not show regional brain or species differences. However, there were clear age-related differences in functional activity, with PepT2 dominating in neonatal mice and rats, and PhT1 dominating in adult rodents. These developmental changes may markedly impact the neural activity of both endogenous and exogenous (drug) peptides/mimetics. Developmental gene and protein expression of peptide transporters was evaluated in various regions of rodent brain, along with age-dependent uptake of dipeptide. We found marked changes in protein expression and functional activity of PhT1 and PepT2, the former predominating in adult and the latter in neonate. These developmental changes may markedly impact the neural activity of endogenous and exogenous peptides/mimetics.
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Affiliation(s)
- Yongjun Hu
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Michigan, Ann Arbor, MI, USA
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Smith DE, Clémençon B, Hediger MA. Proton-coupled oligopeptide transporter family SLC15: physiological, pharmacological and pathological implications. Mol Aspects Med 2013; 34:323-36. [PMID: 23506874 DOI: 10.1016/j.mam.2012.11.003] [Citation(s) in RCA: 218] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2012] [Accepted: 06/22/2012] [Indexed: 01/04/2023]
Abstract
Mammalian members of the proton-coupled oligopeptide transporter family (SLC15) are integral membrane proteins that mediate the cellular uptake of di/tripeptides and peptide-like drugs. The driving force for uphill electrogenic symport is the chemical gradient and membrane potential which favors proton uptake into the cell along with the peptide/mimetic substrate. The peptide transporters are responsible for the absorption and conservation of dietary protein digestion products in the intestine and kidney, respectively, and in maintaining homeostasis of neuropeptides in the brain. They are also responsible for the absorption and disposition of a number of pharmacologically important compounds including some aminocephalosporins, angiotensin-converting enzyme inhibitors, antiviral prodrugs, and others. In this review, we provide updated information on the structure-function of PepT1 (SLC15A1), PepT2 (SLC15A2), PhT1 (SLC15A4) and PhT2 (SLC15A3), and their expression and localization in key tissues. Moreover, mammalian peptide transporters are discussed in regard to pharmacogenomic and regulatory implications on host pharmacology and disease, and as potential targets for drug delivery. Significant emphasis is placed on the evolving role of these peptide transporters as elucidated by studies using genetically modified animals. Whenever possible, the relevance of drug-drug interactions and regulatory mechanisms are evaluated using in vivo studies.
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Affiliation(s)
- David E Smith
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Michigan, Ann Arbor, MI 48109, USA.
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Spanier B. Transcriptional and functional regulation of the intestinal peptide transporter PEPT1. J Physiol 2013; 592:871-9. [PMID: 23959672 DOI: 10.1113/jphysiol.2013.258889] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Dietary proteins are cleaved within the intestinal lumen to oligopeptides which are further processed to small peptides (di- and tripeptides) and free amino acids. Although the transport of amino acids is mediated by several specific amino acid transporters, the proton-coupled uptake of the more than 8000 different di- and tripeptides is performed by the high-capacity/low-affinity peptide transporter isoform PEPT1 (SLC15A1). Its wide substrate tolerance also allows the transport of a repertoire of structurally closely related compounds and drugs, which explains their high oral bioavailability and brings PEPT1 into focus for medical and pharmaceutical approaches. Although the first evidence for the interplay of nutrient supply and PEPT1 expression and function was described over 20 years ago, many aspects of the molecular processes controlling its transcription and translation and modifying its transporter properties are still awaiting discovery. The present review summarizes the recent knowledge on the factors modulating PEPT1 expression and function in Caenorhabditis elegans, Danio rerio, Mus musculus and Homo sapiens, with focus on dietary ingredients, transcription factors and functional modulators, such as the sodium-proton exchanger NHE3 and selected scaffold proteins.
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Affiliation(s)
- Britta Spanier
- Biochemistry, Technische Universität München, ZIEL Research Center of Nutrition and Food Sciences, Gregor-Mendel-Straße 2, D-85350 Freising, Germany.
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Mace OJ, Marshall F. DIGESTIVE PHYSIOLOGY OF THE PIG SYMPOSIUM: Gut chemosensing and the regulation of nutrient absorption and energy supply1. J Anim Sci 2013; 91:1932-45. [DOI: 10.2527/jas.2012-5906] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Affiliation(s)
- O. J. Mace
- Heptares Therapeutics, BioPark, Broadwater Road, Welwyn Garden City, AL7 3AX, United Kingdom
| | - F. Marshall
- Heptares Therapeutics, BioPark, Broadwater Road, Welwyn Garden City, AL7 3AX, United Kingdom
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Berthelsen R, Nielsen CU, Brodin B. Basolateral glycylsarcosine (Gly-Sar) transport in Caco-2 cell monolayers is pH dependent. ACTA ACUST UNITED AC 2013; 65:970-9. [PMID: 23738724 DOI: 10.1111/jphp.12061] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2012] [Accepted: 02/11/2013] [Indexed: 12/29/2022]
Abstract
OBJECTIVES Transepithelial di/tripeptide transport in enterocytes occurs via the apical proton-coupled peptide transporter, hPEPT1 (SLC15A1) and a basolateral peptide transporter, which has only been characterized functionally. In this study we examined the pH dependency, substrate uptake kinetics and substrate specificity of the transporter. METHODS We studied the uptake of [(14) C]Gly-Sar from basolateral solution into Caco-2 cell monolayers grown for 17-22 days on permeable supports, at a range of basolateral pH values. KEY FINDINGS Basolateral Gly-Sar uptake was pH dependent, with a maximal uptake rate at a basolateral pH of 5.5. Uptake of Gly-Sar decreased in the presence of the protonophore nigericin, indicating that the uptake was proton-coupled. The uptake was saturable, with a maximal flux (Vmax ) of 408 ± 71, 307 ± 25 and 188 ± 19 pmol/cm(2) /min (mean ± S.E., n = 3) at basolateral pH 5.0, 6.0 and 7.4, respectively. The compounds Gly-Asp, Glu-Phe-Tyr, Gly-Glu-Gly, Gly-Phe-Gly, lidocaine and, to a smaller degree, para-aminohippuric acid were all shown to inhibit the basolateral uptake of Gly-Sar. CONCLUSIONS The study showed that basolateral Gly-Sar transport in the intestinal cell line Caco-2 is proton-coupled. The inhibitor profile indicated that the transporter has broad substrate specificity.
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Affiliation(s)
- Ragna Berthelsen
- Department of Pharmacy, The Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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Hu Y, Chen X, Smith DE. Species-dependent uptake of glycylsarcosine but not oseltamivir in Pichia pastoris expressing the rat, mouse, and human intestinal peptide transporter PEPT1. Drug Metab Dispos 2012; 40:1328-35. [PMID: 22490229 DOI: 10.1124/dmd.111.044263] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The purpose of this study was to determine whether glycylsarcosine (a model dipeptide) and oseltamivir (an antiviral prodrug) exhibited a species-dependent uptake in yeast Pichia pastoris expressing the rat, mouse, and human homologs of PEPT1. Experiments were performed with [(3)H]glycylsarcosine (GlySar) in yeast P. pastoris expressing human, mouse, and rat peptide transporter 1 (PEPT1), in which uptake was examined as a function of time, concentration, potential inhibitors, and the dose-response inhibition of GlySar by oseltamivir. Studies with [(14)C]oseltamivir were also performed under identical experimental conditions. We found that GlySar exhibited saturable uptake in all three species, with K(m) values for human (0.86 mM) > mouse (0.30 mM) > rat (0.16 mM). GlySar uptake in the yeast transformants was specific for peptides (glycylproline) and peptide-like drugs (cefadroxil, cephradine, and valacyclovir), but was unaffected by glycine, l-histidine, cefazolin, cephalothin, cephapirin, acyclovir, 4-acetamido-4'-isothiocyanostilbene-2,2'-disulfonic acid, tetraethylammonium, and elacridar. Although oseltamivir caused a dose-dependent inhibition of GlySar uptake [IC(50) values for human (27.4 mM) > rat (18.3 mM) > mouse (10.7 mM)], the clinical relevance of this interaction would be very low in humans. Of importance, oseltamivir was not a substrate for the intestinal PEPT1 transporter in yeast expressing the three mammalian species tested. Instead, the prodrug exhibited nonspecific binding to the yeast vector and PEPT1 transformants. Finally, the mouse appeared to be a better animal model than the rat for exploring the intestinal absorption and pharmacokinetics of peptides and peptide-like drugs in human.
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Affiliation(s)
- Yongjun Hu
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Michigan, 4742C Medical Sciences II, 1150 W. Medical Center Dr., Ann Arbor, MI 48109-5633, USA
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Intestinal gene expression in pigs: effects of reduced feed intake during weaning and potential impact of dietary components. Nutr Res Rev 2011; 24:155-75. [DOI: 10.1017/s0954422411000047] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The weaning transition is characterised by morphological, histological and microbial changes, often leading to weaning-associated disorders. These intestinal changes can partly be ascribed to the lack of luminal nutrition arising from the reduced feed intake common in pigs after weaning. It is increasingly becoming clear that changes in the supply with enteral nutrients may have major impacts on intestinal gene expression. Furthermore, the major dietary constituents, i.e. carbohydrates, fatty acids and amino acids, participate in the regulation of intestinal gene expression. However, nutrients may also escape digestion by mammalian enzymes in the upper gastrointestinal tract. These nutrients can be used by the microflora, resulting in the production of bacterial metabolites, for example, SCFA, which may affect intestinal gene expression indirectly. The present review provides an insight on possible effects of reduced feed intake on intestinal gene expression, as it may occur post-weaning. Detailed knowledge on effects of reduced feed intake on intestinal gene expression may help to understand weaning-associated intestinal dysfunctions and diseases. Examples are given of intestinal genes which may be altered in their expression due to supply with specific nutrients. In that way, gene expression could be modulated by dietary means, thereby acting as a potential therapeutic tool. This could be achieved, for example, by influencing genes coding for digestive or absorptive proteins, thus optimising digestive function and metabolism, but also with regard to immune response, or by influencing proliferative processes, thereby enhancing mucosal repair. This would be of special interest when designing a diet to overcome weaning-associated problems.
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35
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Jappar D, Hu Y, Smith DE. Effect of dose escalation on the in vivo oral absorption and disposition of glycylsarcosine in wild-type and Pept1 knockout mice. Drug Metab Dispos 2011; 39:2250-7. [PMID: 21880829 DOI: 10.1124/dmd.111.041087] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
This study evaluated the in vivo absorption and disposition of glycylsarcosine (GlySar), after escalating oral doses, in wild-type and peptide transporter 1 (Pept1) knockout mice. [(3)H]GlySar was administered to mice at doses of 1, 10, 100, 1000, and 5000 nmol/g b.wt. Serial blood samples were obtained over 480 min, the plasma was harvested, and the area under the plasma concentration-time curve (AUC) was determined. It was observed that the GlySar AUC was 60, 45, and 30% lower in knockout than wild-type mice when evaluated over 2, 4, and 8 h, respectively (p < 0.01). Plasma levels of GlySar reached a plateau at 90 min in knockout mice and then rose to a second plateau at 240 min. In wild-type mice, the plasma levels rose continuously to reach a single plateau at 90 min. When partial AUC (0-120 min) was used as an indicator for rate of absorption, there was a 60% reduction in GlySar absorption rate in knockout mice compared with wild-type animals. Tissue distribution studies were also performed after 10 nmol/g oral doses of [(3)H]GlySar. When sampled 1 h after dosing, GlySar tissue concentrations were significantly lower in knockout versus wild-type mice and, with the exception of intestines, reflected differences in the systemic exposure of dipeptide between these two genotypes. Overall, PEPT1 ablation in mice resulted in significant reductions, in vivo, in the rate and extent of GlySar absorption. The AUC of GlySar was proportional to dose in both genotypes over 1 to 100 nmol/g, with minor decrements at the two highest doses.
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Affiliation(s)
- Dilara Jappar
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Michigan, Ann Arbor, MI, USA
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36
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Liou AP, Chavez DI, Espero E, Hao S, Wank SA, Raybould HE. Protein hydrolysate-induced cholecystokinin secretion from enteroendocrine cells is indirectly mediated by the intestinal oligopeptide transporter PepT1. Am J Physiol Gastrointest Liver Physiol 2011; 300:G895-902. [PMID: 21311026 PMCID: PMC3094145 DOI: 10.1152/ajpgi.00521.2010] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Dietary protein is a major stimulant for cholecystokinin (CCK) secretion by the intestinal I cell, however, the mechanism by which protein is detected is unknown. Indirect functional evidence suggests that PepT1 may play a role in CCK-mediated changes in gastric motor function. However, it is unclear whether this oligopeptide transporter directly or indirectly activates the I cell. Using both the CCK-expressing enteroendocrine STC-1 cell and acutely isolated native I cells from CCK-enhanced green fluorescent protein (eGFP) mice, we aimed to determine whether PepT1 directly activates the enteroendocrine cell to elicit CCK secretion in response to oligopeptides. Both STC-1 cells and isolated CCK-eGFP cells expressed PepT1 transcripts. STC-1 cells were activated, as measured by ERK(1/2) phosphorylation, by both peptone and the PepT1 substrate Cefaclor; however, the PepT1 inhibitor 4-aminomethyl benzoic acid (AMBA) had no effect on STC-1 cell activity. The PepT1-transportable substrate glycyl-sarcosine dose-dependently decreased gastric motility in anesthetized rats but had no affect on activation of STC-1 cells or on CCK secretion by CCK-eGFP cells. CCK secretion was significantly increased in response to peptone but not to Cefaclor, cephalexin, or Phe-Ala in CCK-eGFP cells. Taken together, the data suggest that PepT1 does not directly mediate CCK secretion in response to PepT1 specific substrates. PepT1, instead, may have an indirect role in protein sensing in the intestine.
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Affiliation(s)
- Alice P. Liou
- 1Department of Anatomy, Physiology, and Cell Biology, School of Veterinary Medicine, University of California-Davis, Davis, California; and ,2Digestive Diseases Branch, National Institute of Diabetes, Digestive, and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
| | - Diana I. Chavez
- 1Department of Anatomy, Physiology, and Cell Biology, School of Veterinary Medicine, University of California-Davis, Davis, California; and
| | - Elvis Espero
- 1Department of Anatomy, Physiology, and Cell Biology, School of Veterinary Medicine, University of California-Davis, Davis, California; and
| | - Shuzhen Hao
- 1Department of Anatomy, Physiology, and Cell Biology, School of Veterinary Medicine, University of California-Davis, Davis, California; and
| | - Stephen A. Wank
- 2Digestive Diseases Branch, National Institute of Diabetes, Digestive, and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
| | - Helen E. Raybould
- 1Department of Anatomy, Physiology, and Cell Biology, School of Veterinary Medicine, University of California-Davis, Davis, California; and
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37
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Anderson CMH, Thwaites DT. Hijacking solute carriers for proton-coupled drug transport. Physiology (Bethesda) 2011; 25:364-77. [PMID: 21186281 DOI: 10.1152/physiol.00027.2010] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The physiological role of mammalian solute carrier (SLC) proteins is to mediate transmembrane movement of electrolytes, nutrients, micronutrients, vitamins, and endogenous metabolites from one cellular compartment to another. Many transporters in the small intestine, kidney, and solid tumors are H(+)-coupled, driven by local H(+)-electrochemical gradients, and transport numerous drugs. These transporters include PepT1 and PepT2 (SLC15A1/2), PCFT (SLC46A1), PAT1 (SLC36A1), OAT10 (SLC22A13), OATP2B1 (SLCO2B1), MCT1 (SLC16A1), and MATE1 and MATE2-K (SLC47A1/2).
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Affiliation(s)
- Catriona M H Anderson
- Epithelial Research Group, Institute for Cell & Molecular Biosciences, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, United Kingdom
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38
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Liu Z, Wang C, Liu Q, Meng Q, Cang J, Mei L, Kaku T, Liu K. Uptake, transport and regulation of JBP485 by PEPT1 in vitro and in vivo. Peptides 2011; 32:747-54. [PMID: 21262302 DOI: 10.1016/j.peptides.2011.01.019] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2010] [Revised: 01/12/2011] [Accepted: 01/12/2011] [Indexed: 11/25/2022]
Abstract
Cyclo-trans-4-L-hydroxyprolyl-L-serine (JBP485) is a dipeptide with anti-hepatitis activity that has been chemically synthesized. Previous experiments in rats showed that JBP485 was well absorbed by the intestine after oral administration. The human peptide transporter (PEPT1) is expressed in the intestine and recognizes compounds such as dipeptides and tripeptides. The purposes of this study were to determine if JBP485 acted as a substrate for intestinal PEPT1, and to investigate the characteristics of JBP485 uptake and transepithelial transport by PEPT1. The uptake of JBP485 was pH dependent in human intestinal epithelial cells Caco-2. And JBP485 uptake was also significantly inhibited by glycylsarcosine (Gly-Sar, a typical substrate for PEPT1 transporters), JBP923 (a derivative of JBP485), and cephalexin (CEX, a β-lactam antibiotic and a known substrate of PEPT1) in Caco-2 cells. The rate of apical-to-basolateral transepithelial transport of JBP485 was 1.84 times higher than that for basolateral-to-apical transport. JBP485 transport was obviously inhibited by Gly-Sar, JBP923 and CEX in Caco-2 cells. The uptake of JBP485 was increased by verapamil but not by cyclosporin A (CsA) and inhibited by the presence of Zn(2+) or the toxic metabolite of ethanol, acetaldehyde (AcH) in Caco-2 cells. The in vivo uptake of JBP485 was increased by verapamil and decreased by ethanol in vivo, which was consisted with the in vitro study. PEPT1 mRNA levels were enhanced after exposure of the cells to JBP485 for 24h, compared to control. In conclusion, JBP485 was actively transported by the intestinal oligopeptide transporter PEPT1. This mechanism is likely to contribute to the rapid absorption of JBP485 by the gastrointestinal tract after oral administration.
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Affiliation(s)
- Zhihao Liu
- Department of Clinical Pharmacology, College of Pharmacy, Dalian Medical University, China.
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39
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Abdel-Rahman SM, Newland JG, Kearns GL. Pharmacologic considerations for oseltamivir disposition: focus on the neonate and young infant. Paediatr Drugs 2011; 13:19-31. [PMID: 21162598 DOI: 10.2165/11536950-000000000-00000] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Across much of the world, pandemic H1N1 infection has produced a significant healthcare crisis, reflected in significant morbidity and mortality. Statistics reveal that infection-associated deaths among individuals without pre-existing conditions (e.g. immunosuppression) are clustered in pregnant women and young infants. In developing countries where the availability of influenzae vaccine is limited, the only currently available pharmacologic counter-measure for H1N1 disease is oseltamivir, a neuraminidase inhibitor with excellent in vitro activity against the virus. This drug is available in oral solid and liquid formulations, has excellent peroral bioavailability in adults, and generally has a very favorable safety profile. Many observational studies indicate that oseltamivir treatment is associated with symptomatic improvement in pediatric patients with H1N1 infection and, therefore, is considered to represent a viable therapeutic option for use in children. However, the disposition of the ethyl ester prodrug and its active metabolite has not been well characterized in infants and children. Presently, data are available from only two published investigations and preliminary summary information from a recent presentation of an ongoing study. Given that recent in vitro data support the importance of a target exposure-response profile for the active metabolite of oseltamivir and that many processes known to modulate drug disposition have a developmental basis, understanding the potential impact of age on oseltamivir disposition becomes crucial in the development of age-appropriate dosing regimens for the drug. In this review, the impact of ontogeny on processes that are important in regulating the absorption, distribution, metabolism, and excretion of oseltamivir and its active metabolite are considered. Data from both animal and human investigations are presented in the context of defining how development might influence the dose-exposure relationship and, most importantly, the significant variability associated with it. In addition, the available pediatric pharmacokinetic data for oseltamivir and its active metabolite are summarized and current 'information gaps' deserving of future study are presented.
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Affiliation(s)
- Susan M Abdel-Rahman
- Division of Clinical Pharmacology and Medical Toxicology, The Childrens Mercy Hospitals and Clinics, Kansas City, Missouri 64108, USA.
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40
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Ma K, Hu Y, Smith DE. Peptide transporter 1 is responsible for intestinal uptake of the dipeptide glycylsarcosine: studies in everted jejunal rings from wild-type and Pept1 null mice. J Pharm Sci 2010; 100:767-74. [PMID: 20862774 DOI: 10.1002/jps.22277] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2010] [Revised: 05/21/2010] [Accepted: 05/24/2010] [Indexed: 01/02/2023]
Abstract
The purpose of this study was to determine the relative importance of peptide transporter 1 (PEPT1) in the uptake of peptides/mimetics from mouse small intestine, using glycylsarcosine (GlySar). After isolating jejunal tissue from wild-type and Pept1 null mice, 2 cm intestinal segments were everted and mounted on glass rods for tissue uptake studies. [(14)C]GlySar (4 μM) was studied as a function of time, temperature, sodium and pH, concentration, and potential inhibitors. Compared with wild-type animals, Pept1 null mice exhibited a 78% reduction in GlySar uptake at pH 6.0 at 37°C. GlySar uptake showed pH dependence, with peak values between pH 6.0 and 6.5 in wild-type animals, whereas no such tendency was observed in Pept1 null mice. GlySar exhibited Michaelis-Menten uptake kinetics and a minor nonsaturable component in wild-type animals. In contrast, GlySar uptake occurred only by a nonsaturable process in Pept1 null mice. GlySar uptake was significantly inhibited by dipeptides, aminocephalosporins, angiotensin-converting enzyme inhibitors, and the antiviral prodrug valacyclovir; these inhibitors had little, if any, effect on the uptake of GlySar in Pept1 null mice. The findings demonstrate that PEPT1 plays a critical role in the uptake of GlySar in jejunum and suggest that PEPT1 is the major transporter responsible for the intestinal absorption of small peptides.
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Affiliation(s)
- Katherine Ma
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Michigan, Ann Arbor, Michigan 48109, USA
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41
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Gilbert E, Li H, Emmerson D, Webb K, Wong E. Dietary protein composition influences abundance of peptide and amino acid transporter messenger ribonucleic acid in the small intestine of 2 lines of broiler chicks. Poult Sci 2010; 89:1663-76. [DOI: 10.3382/ps.2010-00801] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
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42
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Jappar D, Wu SP, Hu Y, Smith DE. Significance and regional dependency of peptide transporter (PEPT) 1 in the intestinal permeability of glycylsarcosine: in situ single-pass perfusion studies in wild-type and Pept1 knockout mice. Drug Metab Dispos 2010; 38:1740-6. [PMID: 20660104 DOI: 10.1124/dmd.110.034025] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The purpose of this study was to evaluate the role, relevance, and regional dependence of peptide transporter (PEPT) 1 expression and function in mouse intestines using the model dipeptide glycylsarcosine (GlySar). After isolating specific intestinal segments, in situ single-pass perfusions were performed in wild-type and Pept1 knockout mice. The permeability of [(3)H]GlySar was measured as a function of perfusate pH, dipeptide concentration, potential inhibitors, and intestinal segment, along with PEPT1 mRNA and protein. We found the permeability of GlySar to be saturable (K(m) = 5.7 mM), pH-dependent (maximal value at pH 5.5), and specific for PEPT1; other peptide transporters, such as PHT1 and PHT2, were not involved, as judged by the lack of GlySar inhibition by excess concentrations of histidine. GlySar permeabilities were comparable in the duodenum and jejunum of wild-type mice but were much larger than that in ileum (approximately 2-fold). A PEPT1-mediated permeability was not observed for GlySar in the colon of wild-type mice (<10% residual uptake compared to proximal small intestine). Moreover, GlySar permeabilities were very low and not different in the duodenum, jejunum, ileum, and colon of Pept1 knockout mice. Functional activity of intestinal PEPT1 was confirmed by real-time polymerase chain reaction and immunoblot analyses. Our findings suggest that a loss of PEPT1 activity (e.g., due to polymorphisms, disease, or drug interactions) should have a major effect in reducing the intestinal absorption of di-/tripeptides, peptidomimetics, and peptide-like drugs.
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Affiliation(s)
- Dilara Jappar
- University of Michigan, 4742 Medical Sciences II, 1150 W Medical Center Drive, Ann Arbor, MI 48109-5633, USA
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43
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Errasti-Murugarren E, Pastor-Anglada M. Drug transporter pharmacogenetics in nucleoside-based therapies. Pharmacogenomics 2010; 11:809-41. [PMID: 20504255 DOI: 10.2217/pgs.10.70] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
This article focuses on the different types of transporter proteins that have been implicated in the influx and efflux of nucleoside-derived drugs currently used in the treatment of cancer, viral infections (i.e., AIDS) and other conditions, including autoimmune and inflammatory diseases. Genetic variations in nucleoside-derived drug transporter proteins encoded by the gene families SLC15, SLC22, SLC28, SLC29, ABCB, ABCC and ABCG will be specifically considered. Variants known to affect biological function are summarized, with a particular emphasis on those for which clinical correlations have already been established. Given that relatively little is known regarding the genetic variability of the players involved in determining nucleoside-derived drug bioavailability, it is anticipated that major challenges will be faced in this area of research.
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Affiliation(s)
- Ekaitz Errasti-Murugarren
- The Department of Biochemistry and Molecular Biology, Institute of Biomedicine, University of Barcelona, Diagonal 645, 08028 Barcelona, Spain
- Center for Biomedical Research Network in the Subject Area of Liver and Digestive Diseases (CIBERehd), Barcelona 08071, Spain
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44
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Dietary protein hydrolysates and free amino acids affect the spatial expression of peptide transporter PepT1 in the digestive tract of Atlantic cod (Gadus morhua). Comp Biochem Physiol B Biochem Mol Biol 2010; 156:48-55. [PMID: 20144729 DOI: 10.1016/j.cbpb.2010.02.002] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2009] [Revised: 01/26/2010] [Accepted: 02/01/2010] [Indexed: 02/06/2023]
Abstract
The effects of dietary inclusions of size-fractionated peptides and free amino acids (FAAs) on Peptide Transporter 1 (PepT1) mRNA levels were assessed along the length of the intestine of juvenile Atlantic cod (Gadus morhua). Five groups of fish (10-15g) were fed for 46days on diets containing approximately 42% protein, provided either as fish meal (FM, control diet) or as a combination of FM with whole fish hydrolysate (FH), retenate after ultrafiltration of FH (UFR), nanofiltered retenate of FH (NFR), or a mix of FAAs, at a 30% level of FM substitution. PepT1 mRNA expression was assessed in pyloric caeca (S1) and the remainder of the intestine divided into four equally long segments (S2-S5). PepT1 transcripts were found in all segments, indicating that the whole intestine is involved in peptide absorption. Differences in the regional expression profile of PepT1 were found. Under control diet (FM diet) conditions, fish exhibited a reduced expression in S5 compared to S2. In fish fed FAA and UFR diets, PepT1 mRNA levels were higher in S2 and S3 compared to other regions. These data suggest that PepT1 may be variably recruited along the whole intestine, including the most distal part, in response to changes in the luminal protein source content. This adaptive response might be functional to keep a maximal efficiency of protein absorption at the intestinal level.
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45
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Anderson CMH, Jevons M, Thangaraju M, Edwards N, Conlon NJ, Woods S, Ganapathy V, Thwaites DT. Transport of the photodynamic therapy agent 5-aminolevulinic acid by distinct H+-coupled nutrient carriers coexpressed in the small intestine. J Pharmacol Exp Ther 2009; 332:220-8. [PMID: 19789362 DOI: 10.1124/jpet.109.159822] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
5-Aminolevulinic acid (ALA) is a prodrug used in photodynamic therapy, fluorescent diagnosis, and fluorescent-guided resection because it leads to accumulation of the photosensitizer protoporphyrin IX (PpIX) in tumor tissues. ALA has good oral bioavailability, but high oral doses are required to obtain selective PpIX accumulation in colonic tumors because accumulation is also observed in normal gut mucosa. Structural similarities between ALA and GABA led us to test the hypothesis that the H(+)-coupled amino acid transporter PAT1 (SLC36A1) will contribute to luminal ALA uptake. Radiolabel uptake and electrophysiological measurements identified PAT1-mediated H(+)-coupled ALA symport after heterologous expression in Xenopus oocytes. The selectivity of the nontransported inhibitors 5-hydroxytryptophan and 4-aminomethylbenzoic acid for, respectively, PAT1 and the H(+)-coupled di/tripeptide transporter PepT1 (SLC15A1) were examined. 5-Hydroxytryptophan selectively inhibited PAT1-mediated amino acid uptake across the brush-border membrane of the human intestinal (Caco-2) epithelium whereas 4-aminomethylbenzoic acid selectively inhibited PepT1-mediated dipeptide uptake. The inhibitory effects of 5-hydroxytryptophan and 4-aminomethylbenzoic acid were additive, demonstrating that both PAT1 and PepT1 contribute to intestinal transport of ALA. This is the first demonstration of overlap in substrate specificity between these distinct transporters for amino acids and dipeptides. PAT1 and PepT1 expression was monitored by reverse transcriptase-polymerase chain reaction using paired samples of normal and cancer tissue from human colon. mRNA for both transporters was detected. PepT1 mRNA was increased 2.3-fold in cancer tissues. Thus, increased PepT1 expression in colonic cancer could contribute to the increased PpIX accumulation observed. Selective inhibition of PAT1 could enhance PpIX loading in tumor tissue relative to that in normal tissue.
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Affiliation(s)
- Catriona M H Anderson
- Epithelial Research Group, Institute for Cell and Molecular Biosciences, Faculty of Medical Sciences, Framlington Place, Newcastle University, Newcastle upon Tyne, UK
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46
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Raybould HE. Nutrient sensing in the gastrointestinal tract: possible role for nutrient transporters. J Physiol Biochem 2009; 64:349-56. [PMID: 19391461 DOI: 10.1007/bf03174091] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Although it is well established that the presence of nutrients in the gut lumen can bring about changes in GI function, the mechanisms and pathways by which these changes occur has not been fully elucidated. It has been known for many years that luminal nutrients stimulate the release of hormones and regulatory peptides from gut endocrine cells and that luminal nutrients activate intrinsic and extrinsic neural pathways innervating the gut. Activation of gut endocrine cells and neural pathways by nutrients in the gut lumen is key in coordination of postprandial GI function and also in the regulation of food intake. Recent evidence suggests that these pathways can be modified by long term changes in diet or by inflammatory processes in the gut wall. Thus it is important to determine the cellular and molecular mechanisms underlying these processes not only to increase our understanding of as part of basic physiology but also to understand changes in these pathways that occur in the presence of pathophysiology and disease. This review summarizes some of the latest data that we have obtained, together with information from the other laboratories, which have elucidated some of the mechanisms involved in nutrient detection in the gut wall. The focus is on monosaccharides and protein hydrolysates as there is some evidence for a role for nutrient transporters in detection of these nutrients.
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Affiliation(s)
- H E Raybould
- Dept. Anatomy, Physiology and Cell Biology, UC Davis School of Veterinary Medicine, Davis, CA 95616, USA.
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47
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Rubio-Aliaga I, Daniel H. Peptide transporters and their roles in physiological processes and drug disposition. Xenobiotica 2008; 38:1022-42. [PMID: 18668438 DOI: 10.1080/00498250701875254] [Citation(s) in RCA: 158] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
1. The peptide transporters belong to the peptide transporter (PTR) family and serve as integral membrane proteins for the cellular uptake of di- and tripeptides in the organism. By their ability also to transport peptidomimetics and other substrates with therapeutic activities or precursors of pharmacologically active agents, they are of considerable importance in pharmacology. 2. PEPT1 is the low-affinity, high-capacity transporter and is mainly expressed in the small intestine, whereas PEPT2 is the high-affinity, low-capacity transporter and has a broader distribution in the organism. 3. Targeted mouse models have revealed PEPT2 to be the dominant transporter for the reabsorption of di- and tripeptides and its pharmacological substrates in the organism, and for the removal of these substrates from the cerebrospinal fluid. Moreover, the peptide transporters undergo physiological and pharmacological regulation and, of great interest, are present in disease states where PEPT1 exhibits ectopic expression in colonic inflammation. 4. The paper reviews the structural characteristics of the peptide transporters, the structural requirements for substrates, the distribution of the peptide transporters in the organism, and finally their regulation in the organism in healthy and pathological situations.
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Affiliation(s)
- I Rubio-Aliaga
- Molecular Nutrition Unit, Technical University of Munich, Freising-Weihenstephan, Germany
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48
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Hu Y, Smith DE, Ma K, Jappar D, Thomas W, Hillgren KM. Targeted Disruption of Peptide Transporter Pept1 Gene in Mice Significantly Reduces Dipeptide Absorption in Intestine. Mol Pharm 2008; 5:1122-30. [DOI: 10.1021/mp8001655] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Yongun Hu
- Department of Pharmaceutical Sciences, University of Michigan, Ann Arbor, Michigan 48109, Deltagen, San Mateo, California, and Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, Indiana
| | - David E. Smith
- Department of Pharmaceutical Sciences, University of Michigan, Ann Arbor, Michigan 48109, Deltagen, San Mateo, California, and Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, Indiana
| | - Ke Ma
- Department of Pharmaceutical Sciences, University of Michigan, Ann Arbor, Michigan 48109, Deltagen, San Mateo, California, and Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, Indiana
| | - Dilara Jappar
- Department of Pharmaceutical Sciences, University of Michigan, Ann Arbor, Michigan 48109, Deltagen, San Mateo, California, and Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, Indiana
| | - Winston Thomas
- Department of Pharmaceutical Sciences, University of Michigan, Ann Arbor, Michigan 48109, Deltagen, San Mateo, California, and Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, Indiana
| | - Kathleen M. Hillgren
- Department of Pharmaceutical Sciences, University of Michigan, Ann Arbor, Michigan 48109, Deltagen, San Mateo, California, and Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, Indiana
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49
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Frazier S, Ajiboye K, Olds A, Wyatt T, Luetkemeier ES, Wong EA. Functional Characterization of the Chicken Peptide Transporter 1 (Pept1, Slc15a1) Gene. Anim Biotechnol 2008; 19:201-10. [DOI: 10.1080/10495390802240206] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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50
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Mertl M, Daniel H, Kottra G. Substrate-induced changes in the density of peptide transporter PEPT1 expressed in Xenopus oocytes. Am J Physiol Cell Physiol 2008; 295:C1332-43. [PMID: 18799652 DOI: 10.1152/ajpcell.00241.2008] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The adaptation of the capacity of the intestinal peptide transporter PEPT1 to varying substrate concentrations may be important with respect to its role in providing bulk quantities of amino acids for growth, development, and other nutritional needs. In the present study, we describe a novel phenomenon of the regulation of PEPT1 in the Xenopus oocyte system. Using electrophysiological and immunofluorescence methods, we demonstrate that a prolonged substrate exposure of rabbit PEPT1 (rPEPT1) caused a retrieval of transporters from the membrane. Capacitance as a measure of membrane surface area was increased in parallel with the increase in rPEPT1-mediated transport currents with a slope of approximately 5% of basal surface per 100 nA. Exposure of oocytes to the model peptide Gly-l-Gln for 2 h resulted in a decrease in maximal transport currents with no change of membrane capacitance. However, exposure to substrate for 5 h decreased transport currents but also, in parallel, surface area by endocytotic removal of transporter proteins from the surface. The reduction of the surface expression of rPEPT1 was confirmed by presteady-state current measurements and immunofluorescent labeling of rPEPT1. A similar simultaneous decrease of current and surface area was also observed when endocytosis was stimulated by the activation of PKC. Cytochalasin D inhibited all changes evoked by either dipeptide or PKC stimulation, whereas the PKC-selective inhibitor bisindolylmaleimide only affected PKC-stimulated endocytotic processes but not substrate-dependent retrieval of rPEPT1. Coexpression experiments with human Na(+)-glucose transporter 1 (hSGLT1) revealed that substrate exposure selectively affected PEPT1 but not the activity of hSGLT1.
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Affiliation(s)
- Manuela Mertl
- Molecular Nutrition Unit, Am Forum 5, Freising 85350, Germany
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