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Wang C, Chu C, Ji X, Luo G, Xu C, He H, Yao J, Wu J, Hu J, Jin Y. Biology of Peptide Transporter 2 in Mammals: New Insights into Its Function, Structure and Regulation. Cells 2022; 11:cells11182874. [PMID: 36139448 PMCID: PMC9497230 DOI: 10.3390/cells11182874] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Revised: 09/09/2022] [Accepted: 09/12/2022] [Indexed: 11/16/2022] Open
Abstract
Peptide transporter 2 (PepT2) in mammals plays essential roles in the reabsorption and conservation of peptide-bound amino acids in the kidney and in maintaining neuropeptide homeostasis in the brain. It is also of significant medical and pharmacological significance in the absorption and disposing of peptide-like drugs, including angiotensin-converting enzyme inhibitors, β-lactam antibiotics and antiviral prodrugs. Understanding the structure, function and regulation of PepT2 is of emerging interest in nutrition, medical and pharmacological research. In this review, we provide a comprehensive overview of the structure, substrate preferences and localization of PepT2 in mammals. As PepT2 is expressed in various organs, its function in the liver, kidney, brain, heart, lung and mammary gland has also been addressed. Finally, the regulatory factors that affect the expression and function of PepT2, such as transcriptional activation and posttranslational modification, are also discussed.
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Affiliation(s)
- Caihong Wang
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou 310032, China
- Department of Bioinformatics, College of Life Sciences, Zhejiang University, Hangzhou 310058, China
- Zhejiang Conba Pharmaceutical Limited Company, Hangzhou 310052, China
| | - Chu Chu
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou 310032, China
| | - Xiang Ji
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou 310032, China
| | - Guoliang Luo
- Zhejiang Conba Pharmaceutical Limited Company, Hangzhou 310052, China
- Zhejiang Institute of Modern Chinese Medicine and Natural Medicine, Hangzhou 310052, China
| | - Chunling Xu
- Zhejiang Conba Pharmaceutical Limited Company, Hangzhou 310052, China
- Zhejiang Institute of Modern Chinese Medicine and Natural Medicine, Hangzhou 310052, China
| | - Houhong He
- Zhejiang Conba Pharmaceutical Limited Company, Hangzhou 310052, China
- Zhejiang Institute of Modern Chinese Medicine and Natural Medicine, Hangzhou 310052, China
| | - Jianbiao Yao
- Zhejiang Conba Pharmaceutical Limited Company, Hangzhou 310052, China
- Zhejiang Institute of Modern Chinese Medicine and Natural Medicine, Hangzhou 310052, China
| | - Jian Wu
- Zhejiang Conba Pharmaceutical Limited Company, Hangzhou 310052, China
- Zhejiang Institute of Modern Chinese Medicine and Natural Medicine, Hangzhou 310052, China
| | - Jiangning Hu
- Zhejiang Conba Pharmaceutical Limited Company, Hangzhou 310052, China
- Zhejiang Institute of Modern Chinese Medicine and Natural Medicine, Hangzhou 310052, China
- Correspondence: (J.H.); (Y.J.)
| | - Yuanxiang Jin
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou 310032, China
- Correspondence: (J.H.); (Y.J.)
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Zhou M, Liu G, Liu W, Zhu M, Wang C. Cloning, tissue distribution and functional characterization of the donkey (Equus asinus) oligopeptide transporter 2. J Anim Physiol Anim Nutr (Berl) 2021; 105:1165-1172. [PMID: 34314070 DOI: 10.1111/jpn.13615] [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: 01/19/2021] [Revised: 05/22/2021] [Accepted: 07/13/2021] [Indexed: 11/29/2022]
Abstract
Oligopeptide transporter 2 (PepT2) is an important transporter of oligopeptides. In the present study, we describe the molecular cloning, tissue distribution and functional characterization of a donkey (Equus asinus) PepT2. The cloned cDNA sequence was 2202 bp at full length, encoding a 733 amino acid peptide with a molecular weight of 81.9 kDa and a theoretical pI of 8.92. Bioinformatics analysis showed that the deduced peptide sequence possessed all the characteristic features of PepT2. The expression of PepT2 in the kidney and lung was significantly higher than that observed in the ileum, duodenum, jejunum, spleen, liver, heart and stomach. Functional characterization by heterologous expression in Chinese hamster ovary cells showed that the uptake of β-Ala-Lys-N-7-amino-4-methylcoumarin-3-acetic acid (β-Ala-Lys-AMCA) by donkey PepT2-Chinese hamster ovary cells was dependent on time, pH and substrate concentration, with a low Km value of 91.51 ± 14.14 μM and a maximum velocity of 41.37 ± 2.193 pmol/min/mg protein. In the present study, for the first time, the expression and functional characteristics of donkey PepT2 were evaluated, the results of which provide new insights and a better understanding of its crucial role in oligopeptide transport in donkeys.
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Affiliation(s)
- Miaomiao Zhou
- Liaocheng Research Institute of Donkey High-Efficiency Breeding and Ecological Feeding, College of Agriculture, Liaocheng University, Liaocheng, China
| | - Guiqin Liu
- Liaocheng Research Institute of Donkey High-Efficiency Breeding and Ecological Feeding, College of Agriculture, Liaocheng University, Liaocheng, China
| | - Wenqiang Liu
- Liaocheng Research Institute of Donkey High-Efficiency Breeding and Ecological Feeding, College of Agriculture, Liaocheng University, Liaocheng, China
| | - Mingxia Zhu
- Liaocheng Research Institute of Donkey High-Efficiency Breeding and Ecological Feeding, College of Agriculture, Liaocheng University, Liaocheng, China
| | - Changfa Wang
- Liaocheng Research Institute of Donkey High-Efficiency Breeding and Ecological Feeding, College of Agriculture, Liaocheng University, Liaocheng, China
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Song F, Hu Y, Jiang H, Smith DE. Species Differences in Human and Rodent PEPT2-Mediated Transport of Glycylsarcosine and Cefadroxil in Pichia Pastoris Transformants. Drug Metab Dispos 2016; 45:130-136. [PMID: 27836942 DOI: 10.1124/dmd.116.073320] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Accepted: 11/09/2016] [Indexed: 11/22/2022] Open
Abstract
The proton-coupled oligopeptide transporter PEPT2 (SLC15A2) plays an important role in the disposition of di/tripeptides and peptide-like drugs in kidney and brain. However, unlike PEPT1 (SLC15A1), there is little information about species differences in the transport of PEPT2-mediated substrates. The purpose of this study was to determine whether PEPT2 exhibited a species-dependent uptake of glycylsarcosine (GlySar) and cefadroxil using yeast Pichia pastoris cells expressing cDNA from human, mouse, and rat. In such a system, the functional activity of PEPT2 was evaluated with [3H]GlySar as a function of time, pH, substrate concentration, and specificity, and with [3H]cefadroxil as a function of concentration. We observed that the uptake of GlySar was pH-dependent with an optimal uptake at pH 6.5 for all three species. Moreover, GlySar showed saturable uptake kinetics, with Km values in human (150.6 µM) > mouse (42.8 µM) ≈ rat (36.0 µM). The PEPT2-mediated uptake of GlySar in yeast transformants was specific, being inhibited by di/tripeptides and peptide-like drugs, but not by amino acids and nonsubstrate compounds. Cefadroxil also showed a saturable uptake profile in all three species, with Km values in human (150.8 μM) > mouse (15.6 μM) ≈ rat (11.9 μM). These findings demonstrated that the PEPT2-mediated uptake of GlySar and cefadroxil was specific, species dependent, and saturable. Furthermore, based on the Km values, mice appeared similar to rats but both were less than optimal as animal models in evaluating the renal reabsorption and pharmacokinetics of peptides and peptide-like drugs in humans.
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Affiliation(s)
- Feifeng Song
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Michigan, Ann Arbor, Michigan (Y.H., D.E.S.); and Laboratory of Pharmaceutical Analysis and Drug Metabolism, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang, China (F.S., H.J.)
| | - Yongjun Hu
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Michigan, Ann Arbor, Michigan (Y.H., D.E.S.); and Laboratory of Pharmaceutical Analysis and Drug Metabolism, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang, China (F.S., H.J.)
| | - Huidi Jiang
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Michigan, Ann Arbor, Michigan (Y.H., D.E.S.); and Laboratory of Pharmaceutical Analysis and Drug Metabolism, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang, China (F.S., H.J.)
| | - David E Smith
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Michigan, Ann Arbor, Michigan (Y.H., D.E.S.); and Laboratory of Pharmaceutical Analysis and Drug Metabolism, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang, China (F.S., H.J.)
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Abstract
Oligopeptide transporters serve important functions in nutrition and pharmacology. In particular, these transporters help maintain the homeostasis of peptides. The peptide-transporter PEPT2 is a high-affinity and low-capacity type oligopeptide transporter from the proton-coupled oligopeptide transporter family. PEPT2 has recently received attention because of its potential application in targeted drug delivery. PEPT2 is widely distributed in kidney, central nervous system, and lung of organisms. In general, all dipeptides, tripeptides, and peptide-like drugs such as β-lactam antibiotics and angiotensin-converting enzyme inhibitors could be mediated and transported as a substrate of PEPT2. The design of many extant drugs and prodrugs is based on the substrate structure of PEPT2 to accelerate absorption via peptide transporters. Thus, this paper summarizes the substrate features of PEPT2 to promote the rational design of drugs and prodrugs that target peptide transporters.
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Affiliation(s)
- Dongxin Zhao
- School of Chemistry and Chemical Engineering, Henan University of Technology
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Rasmussen RN, Lagunas C, Plum J, Holm R, Nielsen CU. Interaction of GABA-mimetics with the taurine transporter (TauT, Slc6a6) in hyperosmotic treated Caco-2, LLC-PK1 and rat renal SKPT cells. Eur J Pharm Sci 2015; 82:138-46. [PMID: 26631583 DOI: 10.1016/j.ejps.2015.11.020] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Revised: 11/11/2015] [Accepted: 11/25/2015] [Indexed: 10/22/2022]
Abstract
The aim of the present study was to investigate if basic GABA-mimetics interact with the taurine transporter (TauT, Slc6a6), and to find a suitable cell based model that is robust towards extracellular changes in osmolality during uptake studies. Taurine uptake was measured in human Caco-2 cells, porcine LLC-PK1 cells, and rat SKPT cells using radiolabelled taurine. Hyperosmotic conditions were obtained by incubation with raffinose (final osmolality of 500mOsm) for 24h prior to the uptake experiments. Expression of the taurine transporter, TauT, was investigated at the mRNA level by real-time PCR. Uptake of the GABA-mimetics gaboxadol and vigabatrin was investigated in SKPT cells, and quantified by liquid scintillation or HPLC-MS/MS analysis, respectively. The uptake rate of [(3)H]-taurine was Na(+) and Cl(-) and concentration dependent with taurine with an apparent Vmax of 6.3±1.6pmolcm(-2)min(-1) and a Km of 24.9±15.0μM. β-alanine, nipecotic acid, gaboxadol, GABA, vigabatrin, δ-ALA and guvacine inhibited the taurine uptake rate in a concentration dependent manner. The order of affinity for TauT was β-alanine>GABA>nipecotic acid>guvacine>δ-ALA>vigabatrin>gaboxadol with IC50-values of 0.04, 1.07, 2.02, 4.19, 4.94, 31.4 and 39.9mM, respectively. In conclusion, GABA mimetics inhibited taurine uptake in hyperosmotic rat renal SKPT cells. SKPT cells, which seem to be a useful model for investigating taurine transport in the short-term presence of high concentrations of osmolytes. Furthermore, analogues of β-alanine appear to have higher affinities for TauT than GABA-analogues.
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Affiliation(s)
- Rune Nørgaard Rasmussen
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, DK 5230 Odense M, Denmark
| | - Candela Lagunas
- Drug Transporters in ADME, Department of Pharmacy, Faculty of Health and Medical Sciences, Universitetsparken 2, DK 2100, Copenhagen, Denmark
| | - Jakob Plum
- Drug Transporters in ADME, Department of Pharmacy, Faculty of Health and Medical Sciences, Universitetsparken 2, DK 2100, Copenhagen, Denmark
| | - René Holm
- Pharmaceutical Science and CMC Biologics, H. Lundbeck A/S, DK 2500, Valby, Denmark
| | - Carsten Uhd Nielsen
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, DK 5230 Odense M, Denmark.
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