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Gyimesi G, Hediger MA. Transporter-Mediated Drug Delivery. Molecules 2023; 28:molecules28031151. [PMID: 36770817 PMCID: PMC9919865 DOI: 10.3390/molecules28031151] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 01/12/2023] [Accepted: 01/18/2023] [Indexed: 01/27/2023] Open
Abstract
Transmembrane transport of small organic and inorganic molecules is one of the cornerstones of cellular metabolism. Among transmembrane transporters, solute carrier (SLC) proteins form the largest, albeit very diverse, superfamily with over 400 members. It was recognized early on that xenobiotics can directly interact with SLCs and that this interaction can fundamentally determine their efficacy, including bioavailability and intertissue distribution. Apart from the well-established prodrug strategy, the chemical ligation of transporter substrates to nanoparticles of various chemical compositions has recently been used as a means to enhance their targeting and absorption. In this review, we summarize efforts in drug design exploiting interactions with specific SLC transporters to optimize their therapeutic effects. Furthermore, we describe current and future challenges as well as new directions for the advanced development of therapeutics that target SLC transporters.
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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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Wang C, Zhao F, Liu J, Liu H. The ubiquitin ligase Nedd4-2 mediates the regulation of PepT2 by mTORC1 in bovine mammary epithelial cells. ANIMAL NUTRITION 2022; 10:12-18. [PMID: 35601254 PMCID: PMC9111928 DOI: 10.1016/j.aninu.2021.11.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 11/21/2021] [Accepted: 11/23/2021] [Indexed: 11/16/2022]
Abstract
Peptide transporter 2 (PepT2) transports short peptides from the blood into bovine mammary epithelial cells (BMEC) to stimulate milk protein synthesis. Despite the fact that the effect of PepT2 is acknowledged in BMEC, little is known about its regulation. This study was completed to investigate the role of mammalian target of the rapamycin (mTOR) signaling in regulating the expression and function of PepT2 in BMEC. The regulation of PepT2 by mTOR in BMEC was studied in vitro using peptide transport assay, gene silencing, Western blot. The membrane expression of PepT2 and the uptake of β-Ala-Lys-N-7-amino-4-methylcoumarin-3-acetic acid (β-Ala-Lys-AMCA), a model dipeptide, in BMEC were reduced by rapamycin (a mTOR inhibitor) and silencing of either mTOR complex 1 (mTORC1) or mTOR complex 2 (mTORC2), stimulated by DEP domain-containing mTOR-interacting protein (DEPTOR, endogenous inhibitor of mTORC1 and mTORC2) silencing. The trafficking of PepT2 to the membrane and the uptake of β-Ala-Lys-AMCA was promoted by neuronal precursor cell-expressed developmentally down-regulated 4 isoform 2 (Nedd4-2) silencing. The effects of knockdown of mTORC1, but not mTORC2, on cell membrane expression and transport activity of PepT2 was abolished by Nedd4-2 silencing. With immunofluorescence staining, PepT2 was identified to be interacting with Nedd4-2. The Nedd4-2 expression and the interaction between PepT2 and Nedd4-2 was increased through mTORC1 knockdown, indicating an increased ubiquitination of PepT2. The results revealed that mTORC1 can regulate the expression and function of PepT2 through Nedd4-2 in BMEC.
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Kacirova I, Grundmann M, Brozmanova H. Valproic Acid Concentrations in Mothers, Colostrum and Breastfed Infants during the Early Postpartum Period: Comparison with Concentrations Determined during Delivery and in the Mature Milk Period. Pharmaceutics 2021; 13:pharmaceutics13122074. [PMID: 34959355 PMCID: PMC8708593 DOI: 10.3390/pharmaceutics13122074] [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: 10/15/2021] [Revised: 11/24/2021] [Accepted: 11/30/2021] [Indexed: 11/16/2022] Open
Abstract
To obtain information on the transport of valproic acid from mothers to colostrum and breastfed infants, in this cohort study, valproic acid concentrations in maternal serum (90 subjects), colostrum and the serum of breastfed infants were analyzed in years 1993–2018, between the 2nd and 5th postnatal days. Valproic acid concentrations ranged from 4.3 to 66.5 mg/L (mean 31.2 ± 13.6 mg/L) in maternal serum, from 0.5 to 5.9 mg/L (mean 1.1 ± 1.2 mg/L) in milk, and from 0.5 to 42.9 mg/L (mean 15.4 ± 9.4 mg/L) in infant serum. The milk/maternal serum concentration ratio ranged from 0.01 to 0.22 (mean 0.04 ± 0.04), and the infant/maternal serum concentration ratio ranged from 0.01 to 1.61 (mean 0.51 ± 0.28). A significant correlation was found between serum concentrations of breastfed infants and milk concentrations, maternal serum concentrations, maternal daily dose, and dose related to maternal body weight. Valproic acid concentrations in milk and infant serum did not reach the lower limit of the reference range used for the general epileptic population, and three-quarters of the concentrations in milk were lower than the lower limit of quantification. Routine monitoring of serum concentrations of breastfed infants is not necessary. If signs of potential adverse reactions are noted, serum concentrations of the infants should be measured.
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Affiliation(s)
- Ivana Kacirova
- Department of Clinical Pharmacology, Faculty of Medicine, University of Ostrava, 70300 Ostrava, Czech Republic; (I.K.); (H.B.)
- Department of Laboratory Medicine, Institute of Clinical Pharmacology, University Hospital Ostrava, 70852 Ostrava, Czech Republic
| | - Milan Grundmann
- Department of Clinical Pharmacology, Faculty of Medicine, University of Ostrava, 70300 Ostrava, Czech Republic; (I.K.); (H.B.)
- Department of Laboratory Medicine, Institute of Clinical Pharmacology, University Hospital Ostrava, 70852 Ostrava, Czech Republic
- Correspondence: ; Tel.: +420-59-737-4389
| | - Hana Brozmanova
- Department of Clinical Pharmacology, Faculty of Medicine, University of Ostrava, 70300 Ostrava, Czech Republic; (I.K.); (H.B.)
- Department of Laboratory Medicine, Institute of Clinical Pharmacology, University Hospital Ostrava, 70852 Ostrava, Czech Republic
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5
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Robison SW, Li J, Viera L, Blackburn JP, Patel RP, Blalock JE, Gaggar A, Xu X. A mechanism for matrikine regulation in acute inflammatory lung injury. JCI Insight 2021; 6:140750. [PMID: 33830084 PMCID: PMC8119180 DOI: 10.1172/jci.insight.140750] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Accepted: 03/03/2021] [Indexed: 12/12/2022] Open
Abstract
Proline-glycine-proline (PGP) and its acetylated form (Ac-PGP) are neutrophil chemoattractants generated by collagen degradation, and they have been shown to play a role in chronic inflammatory disease. However, the mechanism for matrikine regulation in acute inflammation has not been well established. Here, we show that these peptides are actively transported from the lung by the oligopeptide transporter, PEPT2. Following intratracheal instillation of Ac-PGP in a mouse model, there was a rapid decline in concentration of the labeled peptide in the bronchoalveolar lavage (BAL) over time and redistribution to extrapulmonary sites. In vitro knockdown of the PEPT2 transporter in airway epithelia or use of a competitive inhibitor of PEPT2, cefadroxil, significantly reduced uptake of Ac-PGP. Animals that received intratracheal Ac-PGP plus cefadroxil had higher levels of Ac-PGP in BAL and lung tissue. Utilizing an acute LPS-induced lung injury model, we demonstrate that PEPT2 blockade enhanced pulmonary Ac-PGP levels and lung inflammation. We further validated this effect using clinical samples from patients with acute lung injury in coculture with airway epithelia. This is the first study to our knowledge to determine the in vitro and in vivo significance of active matrikine transport as a mechanism of modulating acute inflammation and to demonstrate that it may serve as a potential therapeutic target.
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Affiliation(s)
- Sarah W Robison
- Department of Medicine, Division of Pulmonology, Allergy and Critical Care Medicine, and.,Program in Protease and Matrix Biology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - JinDong Li
- Department of Medicine, Division of Pulmonology, Allergy and Critical Care Medicine, and.,Program in Protease and Matrix Biology, University of Alabama at Birmingham, Birmingham, Alabama, USA.,Birmingham VA Medical Center, Birmingham, Alabama, USA
| | - Liliana Viera
- Department of Medicine, Division of Pulmonology, Allergy and Critical Care Medicine, and.,Program in Protease and Matrix Biology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Jonathan P Blackburn
- Department of Medicine, Division of Pulmonology, Allergy and Critical Care Medicine, and.,Program in Protease and Matrix Biology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Rakesh P Patel
- Program in Protease and Matrix Biology, University of Alabama at Birmingham, Birmingham, Alabama, USA.,Department of Pathology, Division of Molecular and Cellular Pathology, and.,Center for Free Radical Biology, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - J Edwin Blalock
- Department of Medicine, Division of Pulmonology, Allergy and Critical Care Medicine, and.,Program in Protease and Matrix Biology, University of Alabama at Birmingham, Birmingham, Alabama, USA.,Gregory Fleming James Cystic Fibrosis Research Center, Birmingham, Alabama, USA.,Lung Health Center, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Amit Gaggar
- Department of Medicine, Division of Pulmonology, Allergy and Critical Care Medicine, and.,Program in Protease and Matrix Biology, University of Alabama at Birmingham, Birmingham, Alabama, USA.,Birmingham VA Medical Center, Birmingham, Alabama, USA.,Gregory Fleming James Cystic Fibrosis Research Center, Birmingham, Alabama, USA.,Lung Health Center, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Xin Xu
- Department of Medicine, Division of Pulmonology, Allergy and Critical Care Medicine, and.,Program in Protease and Matrix Biology, University of Alabama at Birmingham, Birmingham, Alabama, USA.,Birmingham VA Medical Center, Birmingham, Alabama, USA.,Gregory Fleming James Cystic Fibrosis Research Center, Birmingham, Alabama, USA.,Lung Health Center, University of Alabama at Birmingham, Birmingham, Alabama, USA
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6
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Nauwelaerts N, Deferm N, Smits A, Bernardini C, Lammens B, Gandia P, Panchaud A, Nordeng H, Bacci ML, Forni M, Ventrella D, Van Calsteren K, DeLise A, Huys I, Bouisset-Leonard M, Allegaert K, Annaert P. A comprehensive review on non-clinical methods to study transfer of medication into breast milk - A contribution from the ConcePTION project. Biomed Pharmacother 2021; 136:111038. [PMID: 33526310 DOI: 10.1016/j.biopha.2020.111038] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Revised: 11/03/2020] [Accepted: 11/16/2020] [Indexed: 12/23/2022] Open
Abstract
Breastfeeding plays a major role in the health and wellbeing of mother and infant. However, information on the safety of maternal medication during breastfeeding is lacking for most medications. This leads to discontinuation of either breastfeeding or maternal therapy, although many medications are likely to be safe. Since human lactation studies are costly and challenging, validated non-clinical methods would offer an attractive alternative. This review gives an extensive overview of the non-clinical methods (in vitro, in vivo and in silico) to study the transfer of maternal medication into the human breast milk, and subsequent neonatal systemic exposure. Several in vitro models are available, but model characterization, including quantitative medication transport data across the in vitro blood-milk barrier, remains rather limited. Furthermore, animal in vivo models have been used successfully in the past. However, these models don't always mimic human physiology due to species-specific differences. Several efforts have been made to predict medication transfer into the milk based on physicochemical characteristics. However, the role of transporter proteins and several physiological factors (e.g., variable milk lipid content) are not accounted for by these methods. Physiologically-based pharmacokinetic (PBPK) modelling offers a mechanism-oriented strategy with bio-relevance. Recently, lactation PBPK models have been reported for some medications, showing at least the feasibility and value of PBPK modelling to predict transfer of medication into the human milk. However, reliable data as input for PBPK models is often missing. The iterative development of in vitro, animal in vivo and PBPK modelling methods seems to be a promising approach. Human in vitro models will deliver essential data on the transepithelial transport of medication, whereas the combination of animal in vitro and in vivo methods will deliver information to establish accurate in vitro/in vivo extrapolation (IVIVE) algorithms and mechanistic insights. Such a non-clinical platform will be developed and thoroughly evaluated by the Innovative Medicines Initiative ConcePTION.
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Affiliation(s)
- Nina Nauwelaerts
- KU Leuven Drug Delivery and Disposition Lab, Department of Pharmaceutical and Pharmacological Sciences, O&N II Herestraat, 49 3000, Leuven, Belgium.
| | - Neel Deferm
- KU Leuven Drug Delivery and Disposition Lab, Department of Pharmaceutical and Pharmacological Sciences, O&N II Herestraat, 49 3000, Leuven, Belgium.
| | - Anne Smits
- Neonatal Intensive Care Unit, University Hospitals Leuven, UZ Leuven, Neonatology, Herestraat 49, 3000, Leuven, Belgium; Department of Development and Regeneration, KU Leuven, Belgium.
| | - Chiara Bernardini
- Department of Veterinary Medical Sciences, University of Bologna, 40064, Ozzano dell'Emilia, BO, Italy.
| | | | - Peggy Gandia
- Laboratoire de Pharmacocinétique et Toxicologie, Centre Hospitalier Universitaire de Toulouse, France.
| | - Alice Panchaud
- Service of Pharmacy Service, Lausanne University Hospital and University of Lausanne, Switzerland; Institute of Primary Health Care (BIHAM), University of Bern, Switzerland
| | - Hedvig Nordeng
- PharmacoEpidemiology and Drug Safety Research Group, Department of Pharmacy, University of Oslo, PB. 1068 Blindern, 0316, Oslo, Norway.
| | - Maria Laura Bacci
- Department of Veterinary Medical Sciences, University of Bologna, 40064, Ozzano dell'Emilia, BO, Italy.
| | - Monica Forni
- Department of Veterinary Medical Sciences, University of Bologna, 40064, Ozzano dell'Emilia, BO, Italy.
| | - Domenico Ventrella
- Department of Veterinary Medical Sciences, University of Bologna, 40064, Ozzano dell'Emilia, BO, Italy.
| | | | - Anthony DeLise
- Novartis Pharmaceuticals Corporation, Novartis Institutes for BioMedical Research, One Health Plaza, East Hanover, NJ, 07936, USA.
| | - Isabelle Huys
- KU Leuven, Department of Clinical Pharmacology and Pharmacotherapy, ON II Herestraat 49 - bus, 521 3000, Leuven, Belgium.
| | - Michele Bouisset-Leonard
- Novartis Pharma AG, Novartis Institutes for BioMedical Research, Werk Klybeck Postfach, Basel, CH-4002, Switzerland.
| | - Karel Allegaert
- Department of Development and Regeneration, KU Leuven, Belgium; KU Leuven, Department of Clinical Pharmacology and Pharmacotherapy, ON II Herestraat 49 - bus, 521 3000, Leuven, Belgium; Department of Clinical Pharmacy, Erasmus MC, Rotterdam, the Netherlands.
| | - Pieter Annaert
- KU Leuven Drug Delivery and Disposition Lab, Department of Pharmaceutical and Pharmacological Sciences, O&N II Herestraat, 49 3000, Leuven, Belgium.
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Dong C, Jiang Z, Zhang X, Feng J, Wang L, Tian X, Xu P, Li X. Phylogeny of Slc15 family and response to Aeromonas hydrophila infection following Lactococcus lactis dietary supplementation in Cyprinus carpio. FISH & SHELLFISH IMMUNOLOGY 2020; 106:705-714. [PMID: 32846240 DOI: 10.1016/j.fsi.2020.08.026] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Revised: 08/06/2020] [Accepted: 08/11/2020] [Indexed: 06/11/2023]
Abstract
Solute carrier 15 family (Slc15) are membrane proteins that utilize the proton gradient and negative membrane protential for the transmembrane transporter of di-/tripeptide and peptide-mimetic molecules, in addition, they also play important roles in immunoreaction. In this study, 10 Slc15 genes were identified in the common carp genome database. Comparative genomics analysis showed considerable expansion of the Slc15 genes and verified the four-round whole genome duplication (WGD) event in common carp. Phylogenetic analysis revealed all Slc15 genes of common carp were clustered into orthologous groups indicating the highly conservative during evolution. Besides, the tissues and temporal expression examined by RT-PCR and qRT-PCR showed that most of the Slc15 genes had a narrow tissue distribution and exhibited tissue-specific expression patterns. Expression divergences were observed between these copies proving function divergence after the WGD. Then, we investigated the dietary supplementation effects of three Lactococcus lactis strains on the expression of Slc15 genes in common carp infected by A. hydrophila to find an effective way to treat aquatic diseases. Almost all of the Slc15 genes had an increased expression trend in the early post-challenge stage, and reached the highest expression level at 12h post-challenge. Then, the expression level showed a bluff descent at the last two stages and the expression level reached the lowest at 48 h post-challenge. Slc15 genes expression is actively up-regulated when stimulated by inflammatory factors, which can "amplify" immune signals, and improve the body's defense against foreign invasion in the early stage of the inflammatory response. So activation of the Slc15 genes may be an effective way for infectious disease treatment. As expected, three strains improved the expression of Slc15 genes variously compared with the control/infection groups. The strain 3 of L. lactis had a better induction of Slc15 genes compared with strain 1 and strain 2. It might be applied as a potential activation of Slc15 genes for disease treatment and adding befitting L. lactis may be a good way to protect aquatilia from bacillosis.
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Affiliation(s)
- Chuanju Dong
- College of Fishery, Henan Normal University, Xinxiang, 453007, China; Key Laboratory of Tropical&Subtropical Fishery Resource Application and Cultivation, Ministry of Agriculture, China; Pearl River Fisheries Research Institute CAFS, Guangdong, 510380, China.
| | - Zhou Jiang
- College of Fishery, Henan Normal University, Xinxiang, 453007, China
| | - Xianyao Zhang
- College of Fishery, Henan Normal University, Xinxiang, 453007, China
| | - Junchang Feng
- College of Fishery, Henan Normal University, Xinxiang, 453007, China
| | - Lei Wang
- College of Fishery, Henan Normal University, Xinxiang, 453007, China
| | - Xue Tian
- College of Fishery, Henan Normal University, Xinxiang, 453007, China
| | - Peng Xu
- College of Fishery, Henan Normal University, Xinxiang, 453007, China; State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, 361005, China
| | - Xuejun Li
- College of Fishery, Henan Normal University, Xinxiang, 453007, China.
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Otto PI, Guimarães SEF, Calus MPL, Vandenplas J, Machado MA, Panetto JCC, da Silva MVGB. Single-step genome-wide association studies (GWAS) and post-GWAS analyses to identify genomic regions and candidate genes for milk yield in Brazilian Girolando cattle. J Dairy Sci 2020; 103:10347-10360. [PMID: 32896396 DOI: 10.3168/jds.2019-17890] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Accepted: 06/19/2020] [Indexed: 12/15/2022]
Abstract
Milk production is economically important to the Brazilian agribusiness, and the majority of the country's milk production derives from Girolando (Gir × Holstein) cows. This study aimed to identify quantitative trait loci (QTL) and candidate genes associated with 305-d milk yield (305MY) in Girolando cattle. In addition, we investigated the SNP-specific variances for Holstein and Gir breeds of origin within the sequence of candidate genes. A single-step genomic BLUP procedure was used to identify QTL associated with 305MY, and the most likely candidate genes were identified through follow-up analyses. Genomic breeding values specific for Holstein and Gir were estimated in the Girolando animals using a model that uses breed-specific partial relationship matrices, which were converted to breed of origin SNP effects. Differences between breed of origin were evaluated by comparing estimated SNP variances between breeds. From 10 genome regions explaining most additive genetic variance for 305MY in Girolando cattle, 7 candidate genes were identified on chromosomes 1, 4, 6, and 26. Within the sequence of these 7 candidate genes, Gir breed of origin SNP alleles showed the highest genetic variance. These results indicated QTL regions that could be further explored in genomic selection panels and which may also help in understanding the gene mechanisms involved in milk production in the Girolando breed.
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Affiliation(s)
- Pamela I Otto
- Department of Animal Science, Universidade Federal de Viçosa, Viçosa, MG, 36570-900, Brazil
| | - Simone E F Guimarães
- Department of Animal Science, Universidade Federal de Viçosa, Viçosa, MG, 36570-900, Brazil
| | - Mario P L Calus
- Animal Breeding and Genomics, Wageningen University & Research, 6700 AH Wageningen, the Netherlands
| | - Jeremie Vandenplas
- Animal Breeding and Genomics, Wageningen University & Research, 6700 AH Wageningen, the Netherlands
| | - Marco A Machado
- Animal Breeding and Genomics, Wageningen University & Research, 6700 AH Wageningen, the Netherlands
| | - João Cláudio C Panetto
- Animal Breeding and Genomics, Wageningen University & Research, 6700 AH Wageningen, the Netherlands
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9
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Ventrella D, Forni M, Bacci ML, Annaert P. Non-clinical Models to Determine Drug Passage into Human Breast Milk. Curr Pharm Des 2020; 25:534-548. [PMID: 30894104 DOI: 10.2174/1381612825666190320165904] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Accepted: 03/18/2019] [Indexed: 12/13/2022]
Abstract
BACKGROUND Successful practice of clinical perinatal pharmacology requires a thorough understanding of the pronounced physiological changes during lactation and how these changes affect various drug disposition processes. In addition, pharmacokinetic processes unique to lactation have remained understudied. Hence, determination of drug disposition mechanisms in lactating women and their babies remains a domain with important knowledge gaps. Indeed, lack of data regarding infant risk during breastfeeding far too often results in discontinuation of breastfeeding and subsequent loss of all the associated benefits to the breastfed infant. In the absence of age-specific toxicity data, human lactation data alone are considered insufficient to rapidly generate the required evidence regarding risks associated with medication use during lactation. METHODS Systematic review of literature to summarize state-of-the art non-clinical approaches that have been developed to explore the mechanisms underlying drug milk excretion. RESULTS Several studies have reported methods to predict (to some extent) milk drug excretion rates based on physicochemical properties of the compounds. In vitro studies with primary mammary epithelial cells appear excellent approaches to determine transepithelial drug transport rates across the mammary epithelium. Several of these in vitro tools have been characterized in terms of transporter expression and activity as compared to the mammary gland tissue. In addition, with the advent of physiology-based pharmacokinetic (PBPK) modelling, these in vitro transport data may prove instrumental in predicting drug milk concentration time profiles prior to the availability of data from clinical lactation studies. In vivo studies in lactating animals have proven their utility in elucidating the mechanisms underlying drug milk excretion. CONCLUSION By combining various non-clinical tools (physicochemistry-based, in vitro and PBPK, in vivo animal) for drug milk excretion, valuable and unique information regarding drug milk concentrations during lactation can be obtained. The recently approved IMI project ConcePTION will address several of the challenges outlined in this review.
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Affiliation(s)
- Domenico Ventrella
- University of Bologna, Department of Veterinary Medical Science, 40064 Ozzano Emilia Bologna, Italy
| | - Monica Forni
- University of Bologna, Department of Veterinary Medical Science, 40064 Ozzano Emilia Bologna, Italy
| | - Maria Laura Bacci
- University of Bologna, Department of Veterinary Medical Science, 40064 Ozzano Emilia Bologna, Italy
| | - Pieter Annaert
- Drug Delivery and Disposition, KU Leuven Department of Pharmaceutical and Pharmacological Sciences, Herestraat 49-box 921, 3000 Leuven, Belgium
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10
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Transporters in the Mammary Gland-Contribution to Presence of Nutrients and Drugs into Milk. Nutrients 2019; 11:nu11102372. [PMID: 31590349 PMCID: PMC6836069 DOI: 10.3390/nu11102372] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Revised: 09/19/2019] [Accepted: 09/25/2019] [Indexed: 02/07/2023] Open
Abstract
A large number of nutrients and bioactive ingredients found in milk play an important role in the nourishment of breast-fed infants and dairy consumers. Some of these ingredients include physiologically relevant compounds such as vitamins, peptides, neuroactive compounds and hormones. Conversely, milk may contain substances-drugs, pesticides, carcinogens, environmental pollutants-which have undesirable effects on health. The transfer of these compounds into milk is unavoidably linked to the function of transport proteins. Expression of transporters belonging to the ATP-binding cassette (ABC-) and Solute Carrier (SLC-) superfamilies varies with the lactation stages of the mammary gland. In particular, Organic Anion Transporting Polypeptides 1A2 (OATP1A2) and 2B1 (OATP2B1), Organic Cation Transporter 1 (OCT1), Novel Organic Cation Transporter 1 (OCTN1), Concentrative Nucleoside Transporters 1, 2 and 3 (CNT1, CNT2 and CNT3), Peptide Transporter 2 (PEPT2), Sodium-dependent Vitamin C Transporter 2 (SVCT2), Multidrug Resistance-associated Protein 5 (ABCC5) and Breast Cancer Resistance Protein (ABCG2) are highly induced during lactation. This review will focus on these transporters overexpressed during lactation and their role in the transfer of products into the milk, including both beneficial and harmful compounds. Furthermore, additional factors, such as regulation, polymorphisms or drug-drug interactions will be described.
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Patel OV, Casey T, Plaut K. Profiling solute-carrier transporters in key metabolic tissues during the postpartum evolution of mammary epithelial cells from nonsecretory to secretory. Physiol Genomics 2019; 51:539-552. [PMID: 31545931 DOI: 10.1152/physiolgenomics.00058.2019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Modifications in the abundance of solute-carrier (SLC) transcripts in tandem with adjustments in genes-associated with energy homeostasis during the postpartum transition of the mammary epithelial cells (MEC) from nonsecretory to secretory is pivotal for supporting milk synthesis. The goal of this study was to identify differentially expressed SLC genes across key metabolic tissues between late pregnancy and onset of lactation. Total RNA was isolated from the mammary, liver, and adipose tissues collected from rat dams on day 20 of pregnancy (P20) and day 1 of lactation (L1) and gene expression was measured with Rat 230 2.0 Affymetrix GeneChips. LIMMA was utilized to identify the differential gene expression patterns between P20 and L1 tissues. Transcripts engaged in conveying anions, cations, carboxylates, sugars, amino acids, metals, nucleosides, vitamins, and fatty acids were significantly increased (P < 0.05) in MEC during the P20 to L1 shift. Downregulated (P < 0.05) genes in the mammary during the physiological transition included GLUT8 and SLC45a3. In the liver, SLC genes encoding for anion, carbonyl, and nucleotide sugar transporters were upregulated (P < 0.05) at L1. while genes facilitating transportation of anions and hexose were increased (P < 0.05), from P20 to L1 in the adipose tissue. GLUT1 and GLUT4 in the liver, along with GLUT4 and SGLT2 in the adipose tissue, were repressed (P < 0.05) at L1. Our results illustrate that MEC exhibit dynamic molecular plasticity during the nonsecretory to secretory transition and increase biosynthetic capacity through a coordinated tissue specific SLC transcriptome modification to facilitate substrate transfer.
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Affiliation(s)
- Osman V Patel
- Department of Cell and Molecular Biology, Grand Valley State University, Allendale, Michigan
| | - Theresa Casey
- Department of Animal Sciences, Purdue University, West Lafayette, Indiana
| | - Karen Plaut
- Department of Animal Sciences, Purdue University, West Lafayette, Indiana
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Wang C, Sun Y, Zhao FQ, Liu J, Liu H. Functional Characterization of Peptide Transporters in Bovine Mammary Epithelial Cells. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2019; 67:213-219. [PMID: 30525553 DOI: 10.1021/acs.jafc.8b05637] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The objective of this study was to characterize the expression profile, transport kinetics, and regulation of peptide transporters in bovine mammary epithelial cells (BMECs). Quantitative reverse-transcription real-time PCR, Western blotting, and immunofluorescence staining were used to investigate the expression of peptide transporters in bovine mammary tissues. The effects of time, pH, concentration, and specific inhibitors on β-alanyl-l-lysyl- Nε-7-amino-4-methyl-coumarin-3-acetic acid (β-Ala-Lys-AMCA) uptake in BMECs were also studied. The results showed that the peptide transporters PepT2 and PhT1 are both expressed in bovine mammary glands. The optimal pH for the uptake of β-Ala-Lys-AMCA in BMECs was 6.5. The transport-kinetics study suggested that the uptake of β-Ala-Lys-AMCA in BMECs is saturable over the tested concentration, with a Km value of 82 ± 18 μM and a Vmax of 124 ± 11 pmol/min per milligram of protein. Other dipeptides, including Gly-Sar, Met-Gly, and Met-Met, competitively inhibited β-Ala-Lys-AMCA uptake in BMECs. However, histidine had no effect on β-Ala-Lys-AMCA uptake. Furthermore, knocking down PepT2 could significantly reduce β-Ala-Lys-AMCA uptake, but PhT1 interference had no effect on peptide uptake in BMECs. The inhibition of PI3K and Akt decreased the uptake of β-Ala-Lys-AMCA. The above results revealed functional characteristics of peptide transporters and demonstrated that PepT2 may play a major role in β-Ala-Lys-AMCA uptake in BMECs. Moreover, the PI3K-Akt signaling pathway may regulate the uptake of β-Ala-Lys-AMCA in BMECs.
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Affiliation(s)
- Caihong Wang
- Institute of Dairy Science, College of Animal Science , Zhejiang University , Hangzhou 310058 , China
| | - Yalu Sun
- Institute of Dairy Science, College of Animal Science , Zhejiang University , Hangzhou 310058 , China
| | - Feng-Qi Zhao
- Institute of Dairy Science, College of Animal Science , Zhejiang University , Hangzhou 310058 , China
- Department of Animal and Veterinary Sciences , University of Vermont , Burlington , Vermont 05405 , United States
| | - Jianxin Liu
- Institute of Dairy Science, College of Animal Science , Zhejiang University , Hangzhou 310058 , China
| | - Hongyun Liu
- Institute of Dairy Science, College of Animal Science , Zhejiang University , Hangzhou 310058 , China
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Kim TI, Kim TG, Lim DH, Kim SB, Park SM, Lim HJ, Kim HJ, Ki KS, Kwon EG, Kim YJ, Mayakrishnan V. The effect of nanoemulsified methionine and cysteine on the in vitro expression of casein in bovine mammary epithelial cells. ASIAN-AUSTRALASIAN JOURNAL OF ANIMAL SCIENCES 2018; 32:257-264. [PMID: 30056657 PMCID: PMC6325390 DOI: 10.5713/ajas.18.0203] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Accepted: 07/09/2018] [Indexed: 01/02/2023]
Abstract
Objective Dairy cattle nutrient requirement systems acknowledge amino acid (AAs) requirements in aggregate as metabolizable protein (MP) and assume fixed efficiencies of MP used for milk protein. Regulation of mammary protein synthesis may be associated with AA input and milk protein output. The aim of this study was to evaluate the effect of nanoemulsified methionine and cysteine on the in-vitro expression of milk protein (casein) in bovine mammary epithelial cells (MAC-T cells). Methods Methionine and cysteine were nonionized using Lipoid S 75 by high-speed homogenizer. The nanoemulsified AA particle size and polydispersity index were determined by dynamic light scattering correlation spectroscopy using a high-performance particle sizer instrument. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was performed to determine the cytotoxicity effect of AAs with and without nanoionization at various concentrations (100 to 500 μg/mL) in mammary epithelial cells. MAC-T cells were subjected to 100% of free AA and nanoemulsified AA concentration in Dulbecco’s modified Eagle medium/nutrient mixture F-12 (DMEM/F12) for the analysis of milk protein (casein) expression by the quantitative reverse transcription polymerase chain reaction method. Results The AA-treated cells showed that cell viability tended to decrease (80%) in proportion to the concentration before nanogenesis, but cell viability increased as much as 90% after nanogenesis. The analysis of the expression of genetic markers related to milk protein indicated that; αs2-casein increased 2-fold, κ-casein increased 5-fold, and the amount of unchanged β-casein expression was nearly doubled in the nanoemulsified methionine-treated group when compared with the free-nanoemulsified methionine-supplemented group. On the contrary, the non-emulsified cysteine-administered group showed higher expression of genetic markers related to milk protein αs2-casein, κ-casein, and β-casein, but all the genetic markers related to milk protein decreased significantly after nanoemulsification. Conclusion Detailed knowledge of factors, such nanogenesis of methionine, associated with increasing cysteine and decreasing production of genetic markers related to milk protein (casein) will help guide future recommendations to producers for maximizing milk yield with a high level of milk protein casein.
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Affiliation(s)
- Tae-Il Kim
- Dairy Science Division, National Institute of Animal Science, Rural Development Administration, Cheonan 31000, Korea
| | - Tae-Gyun Kim
- Department of Food and Biotechnology, Korea University, Sejong 30019, Korea
| | - Dong-Hyun Lim
- Dairy Science Division, National Institute of Animal Science, Rural Development Administration, Cheonan 31000, Korea
| | - Sang-Bum Kim
- Dairy Science Division, National Institute of Animal Science, Rural Development Administration, Cheonan 31000, Korea
| | - Seong-Min Park
- Dairy Science Division, National Institute of Animal Science, Rural Development Administration, Cheonan 31000, Korea
| | - Hyun-Joo Lim
- Dairy Science Division, National Institute of Animal Science, Rural Development Administration, Cheonan 31000, Korea
| | - Hyun-Jong Kim
- Dairy Science Division, National Institute of Animal Science, Rural Development Administration, Cheonan 31000, Korea
| | - Kwang-Seok Ki
- Dairy Science Division, National Institute of Animal Science, Rural Development Administration, Cheonan 31000, Korea
| | - Eung-Gi Kwon
- Hanwoo Research Institute, National Institute of Animal Science, Rural Development Administration, Pyeongchang 25340, Korea
| | - Young-Jun Kim
- Department of Food and Biotechnology, Korea University, Sejong 30019, Korea
| | - Vijayakumar Mayakrishnan
- Dairy Science Division, National Institute of Animal Science, Rural Development Administration, Cheonan 31000, Korea
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Abstract
With the global population rising, the need for sustainable and resource-efficiently produced proteins with nutritional and health promoting qualities has become urgent. Proteins are important macronutrients and are involved in most, if not all, biological processes in the human body. This review discusses these absorption mechanisms in the small intestine. To study intestinal transport and predict bioavailability, cell lines are widely applied as screening models and often concern Caco-2, HT-29, HT-29/MTX and T84 cells. Here, we provide an overview of the presence and activities of peptide- and amino acid transporters in these cell models. Further, inter-laboratory differences are discussed as well as the culture micro-environment, both of which may influence cell culture phenotype and performance. Finally, the value of new developments in the field, including culturing cells in 3-dimensional systems under shear stress (i.e., gut-on-chips), is highlighted. In particular, their suitability in screening novel food proteins and prediction of the nutritional quality needed for inclusion in the human diet of the future is addressed.
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Crisà A, Ferrè F, Chillemi G, Moioli B. RNA-Sequencing for profiling goat milk transcriptome in colostrum and mature milk. BMC Vet Res 2016; 12:264. [PMID: 27884183 PMCID: PMC5123407 DOI: 10.1186/s12917-016-0881-7] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2016] [Accepted: 11/07/2016] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND In this work we aimed at sequencing and assembling the goat milk transcriptome corresponding at colostrum and 120 days of lactation. To reconstruct transcripts we used both the genome as reference, and a de novo assembly approach. Additionally, we aimed at identifying the differentially expressed genes (DEGs) between the two lactation stages and at analyzing the expression of genes involved in oligosaccharides metabolism. RESULTS A total of 44,635 different transcripts, organized in 33,757 tentative genes, were obtained using the goat genome as reference. A significant sequence similarity match was found for 40,353 transcripts (90%) against the NCBI NT and for 35,701 (80%) against the NR databases. 68% and 69% of the de novo assembled transcripts, in colostrum and 120 days of lactation samples respectively, have a significant match with the merged transcriptome obtained using Cufflinks/Cuffmerge. CSN2, PAEP, CSN1S2, CSN3, LALBA, TPT1, FTH1, M-SAA3, SPP1, GLYCAM1, EEF1A1, CTSD, FASN, RPS29, CSN1S1, KRT19 and CHEK1 were found between the top fifteen highly expressed genes. 418 loci were differentially expressed between lactation stages, among which 207 and 122 were significantly up- and down-regulated in colostrum, respectively. Functional annotation and pathway enrichment analysis showed that in goat colostrum somatic cells predominate biological processes involved in glycolysis, carbohydrate metabolism, defense response, cytokine activity, regulation of cell proliferation and cell death, vasculature development, while in mature milk, biological process associated with positive regulation of lymphocyte activation and anatomical structure morphogenesis are enriched. The analysis of 144 different oligosaccharide metabolism-related genes showed that most of these (64%) were more expressed in colostrum than in mature milk, with eight expressed at very high levels (SLCA3, GMSD, NME2, SLC2A1, B4GALT1, B3GNT2, NANS, HEXB). CONCLUSIONS To our knowledge, this is the first study comparing goat transcriptome of two lactation stages: colostrum and 120 days. Our findings suggest putative differences of expression between stages and can be envisioned as a base for further research in the topic. Moreover because a higher expression of genes involved in immune defense response, carbohydrate metabolism and related to oligosaccharide metabolism was identified in colostrum we here corroborate the potential of goat milk as a natural source of lactose-derived oligosaccharides and for the development of functional foods.
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Affiliation(s)
- Alessandra Crisà
- Consiglio per la ricerca in agricoltura e l'analisi dell'economia agraria (CREA) - Animal production research centre, Via Salaria 31, 00015, Monterotondo, Rome, Italy.
| | - Fabrizio Ferrè
- Department of Pharmacy and Biotechnology (FaBiT), University of Bologna Alma Mater, Via Belmeloro 6, 40126, Bologna, Italy
| | - Giovanni Chillemi
- Applications and Innovation Department, CINECA, SCAI SuperComputing, Via dei Tizii 6, 00185, Rome, Italy
| | - Bianca Moioli
- Consiglio per la ricerca in agricoltura e l'analisi dell'economia agraria (CREA) - Animal production research centre, Via Salaria 31, 00015, Monterotondo, Rome, Italy
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Changes in rats' breast tumor ultrastructure and immune and messenger RNA responses caused by dietary Seaweed ( Kappaphycus alvarezii) extract. J Microsc Ultrastruct 2016; 5:70-81. [PMID: 30023239 PMCID: PMC6025758 DOI: 10.1016/j.jmau.2016.08.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Revised: 07/15/2016] [Accepted: 08/13/2016] [Indexed: 12/16/2022] Open
Abstract
The edible red seaweed Kappaphycus alvarezii or Eucheuma cottonii is commercially cultivated in the pristine tropical seas for carrageenan production. The systemic, cellular, and molecular effects of E. cottonii 50% alcohol extract [seaweed E. cottonii ethanol extract (SECE)] on breast cancer were investigated in a rat model. Mammary tumor was induced by subcutaneously injecting LA7 cells in female rat mammary pads. After 2 weeks of cancer growth, the rats received oral administration of either SECE [150 mg/kg body weight (BW) and 300 mg/kg BW] or tamoxifen. Electron microscopy imaging results confirmed macrophage activity and hematoxylin and eosin staining indicated that tumor histopathological alterations were restored toward normal structures by the seaweed extract. The extract suppressed tumor development and modulated the immune responses. This was evidenced by the microscopic observations, the increased spleen weight, size, spleen CD19 B cells, and blood immunoglobulin G (IgG) levels. The extract also increased the circulating total white blood cells, lymphocytes, segmented neutrophils count, T cells (CD3), T-helper cells (CD4), cytotoxic T cell (CD8), and nuclear factor-kappa beta expressions. The extract enhanced cancer cell death, by upregulating the Birc5, Chk1, and p53 levels and downregulating the tumor growth cellular Mdm2 (transformed mouse 3T3 cell double minute 2) messenger RNA (mRNA) expression. The extract showed no toxicity at 150 mg/kg BW in rats. The lectin-rich SECE showed tumor suppression by enhancing immune responses and upregulating the cancer cell apoptosis mRNA expressions.
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Yang JX, Wang CH, Xu QB, Zhao FQ, Liu JX, Liu HY. Methionyl-Methionine Promotes α-s1 Casein Synthesis in Bovine Mammary Gland Explants by Enhancing Intracellular Substrate Availability and Activating JAK2-STAT5 and mTOR-Mediated Signaling Pathways. J Nutr 2015; 145:1748-53. [PMID: 26108540 DOI: 10.3945/jn.114.208330] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Accepted: 05/29/2015] [Indexed: 01/31/2023] Open
Abstract
BACKGROUND Interest is increasing in the role of peptide-bound amino acids (AAs) in milk protein synthesis because studies have found that the uptake of some essential AAs by the mammary gland cannot meet the requirements for milk protein synthesis. Although the role of dipeptides in milk protein synthesis is clearly established, little is known about the underlying mechanisms. OBJECTIVE The objective of this study was to determine whether small peptides can be taken up intact by the peptide transporters in mammary tissue explants and the underlying mechanisms of the effects of methionyl-methionine (Met-Met) supplementation on milk protein synthesis. METHODS Mammary tissue explants were cultured in conditional medium and then treated with different concentrations of Met-Met that replaced 0%, 5%, 10%, 15%, 20%, and 25% of free Met for another 24 h. In some experiments, explants were cultured with an optimal dose of Met-Met with or without the inhibitors of peptide transporter 2 [PepT2; diethylpyrocarbonate (DEPC), 0.1 mmol/L] and aminopeptidase N (APN; bestatin, 20 μmol/L) for 24 h. RESULTS The substitutions of 15% free Met with Met-Met significantly promoted α-s1 casein (αs1-CN) expression in the mammary explants (P < 0.05). The inhibition of the PepT2 by DEPC or APN by bestatin significantly decreased the Met-Met-stimulated increase of αs1-CN expression (P < 0.05). Compared with the control group (0% Met-Met), absorption of Val, Met, Leu, Phe, Lys, and His was improved, and mRNA abundance of the neutral and basic AA transporter was increased in the 15% Met-Met group (P < 0.05). In addition, the mRNA abundance of the mammalian target of rapamycin (mTOR), p70 ribosomal S6 kinase 1 gene, eukaryotic initiation factor 4E binding protein 1 gene , Janus kinase 2 (JAK2), and signal transducer and activator of transcription 5 (STAT5) was increased in the 15% Met-Met-treated group (P < 0.05). CONCLUSION Met-Met promoted αs1-CN synthesis in cultured bovine mammary gland explants, and this stimulation may be mediated by enhanced intracellular substrate availability and by activating JAK2-STAT5 and mTOR signaling pathways.
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Affiliation(s)
- Jian-Xiang Yang
- Institute of Dairy Science, College of Animal Sciences, Zhejiang University, Hangzhou, China; and
| | - Cai-Hong Wang
- Institute of Dairy Science, College of Animal Sciences, Zhejiang University, Hangzhou, China; and
| | - Qing-Biao Xu
- Institute of Dairy Science, College of Animal Sciences, Zhejiang University, Hangzhou, China; and
| | - Feng-Qi Zhao
- Institute of Dairy Science, College of Animal Sciences, Zhejiang University, Hangzhou, China; and Laboratory of Lactation and Metabolic Physiology, Department of Animal Science, University of Vermont, Burlington, VT
| | - Jian-Xin Liu
- Institute of Dairy Science, College of Animal Sciences, Zhejiang University, Hangzhou, China; and
| | - Hong-Yun Liu
- Institute of Dairy Science, College of Animal Sciences, Zhejiang University, Hangzhou, China; and
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Prediction of Drug Transfer into Milk Considering Breast Cancer Resistance Protein (BCRP)-Mediated Transport. Pharm Res 2015; 32:2527-37. [PMID: 25690342 DOI: 10.1007/s11095-015-1641-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2014] [Accepted: 01/27/2015] [Indexed: 01/13/2023]
Abstract
PURPOSE Drug transfer into milk is of concern due to the unnecessary exposure of infants to drugs. Proposed prediction methods for such transfer assume only passive drug diffusion across the mammary epithelium. This study reorganized data from the literature to assess the contribution of carrier-mediated transport to drug transfer into milk, and to improve the predictability thereof. METHODS Milk-to-plasma drug concentration ratios (M/Ps) in humans were exhaustively collected from the literature and converted into observed unbound concentration ratios (M/Punbound,obs). The ratios were also predicted based on passive diffusion across the mammary epithelium (M/Punbound,pred). An in vitro transport assay was performed for selected drugs in breast cancer resistance protein (BCRP)-expressing cell monolayers. RESULTS M/Punbound,obs and M/Punbound,pred values were compared for 166 drugs. M/Punbound,obs values were 1.5 times or more higher than M/Punbound,pred values for as many as 13 out of 16 known BCRP substrates, reconfirming BCRP as the predominant transporter contributing to secretory transfer of drugs into milk. Predictability of M/P values for selected BCRP substrates and non-substrates was improved by considering in vitro-evaluated BCRP-mediated transport relative to passive diffusion alone. CONCLUSIONS The current analysis improved the predictability of drug transfer into milk, particularly for BCRP substrates, based on an exhaustive data overhaul followed by focused in vitro transport experimentation.
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Zhou MM, Wu YM, Liu HY, Liu JX. Effects of phenylalanine and threonine oligopeptides on milk protein synthesis in cultured bovine mammary epithelial cells. J Anim Physiol Anim Nutr (Berl) 2014; 99:215-20. [DOI: 10.1111/jpn.12246] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2013] [Accepted: 08/07/2014] [Indexed: 10/24/2022]
Affiliation(s)
- M. M. Zhou
- Institute of Dairy Science; Ministry of Education Key Laboratory of Molecular Animal Nutrition; Zhejiang University; Hangzhou China
- Weifang University of Science and Technology; Shouguang China
| | - Y. M. Wu
- Institute of Dairy Science; Ministry of Education Key Laboratory of Molecular Animal Nutrition; Zhejiang University; Hangzhou China
| | - H. Y. Liu
- Institute of Dairy Science; Ministry of Education Key Laboratory of Molecular Animal Nutrition; Zhejiang University; Hangzhou China
| | - J. X. Liu
- Institute of Dairy Science; Ministry of Education Key Laboratory of Molecular Animal Nutrition; Zhejiang University; Hangzhou China
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Ito N, Ito K, Ikebuchi Y, Kito T, Miyata H, Toyoda Y, Takada T, Hisaka A, Honma M, Oka A, Kusuhara H, Suzuki H. Organic cation transporter/solute carrier family 22a is involved in drug transfer into milk in mice. J Pharm Sci 2014; 103:3342-8. [PMID: 25175747 DOI: 10.1002/jps.24138] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2014] [Revised: 07/07/2014] [Accepted: 07/28/2014] [Indexed: 01/11/2023]
Abstract
Drug transfer into milk is a general concern during lactation. So far, breast cancer resistance protein (Bcrp) is the only transporter known to be involved in this process, whereas participation of other transporters remains unclear. We investigated the importance of organic cation transporter (Oct) in drug transfer into milk in mice. The mammary glands of lactating versus nonlactating FVB strain mice revealed elevated mRNA levels of Oct1 and Bcrp, whereas Oct2 and Oct3 mRNA levels were decreased. Specific uptake of cimetidine, acyclovir, metformin, and terbutaline was observed in human embryonic kidney 293 cells transfected with murine Oct1 or Oct2. The milk-to-plasma concentration ratio (M/P) values of cimetidine and acyclovir were significantly decreased in Bcrp knockout and Oct1/2 double-knockout (DKO) mice compared with control FVB mice, whereas the M/P values of terbutaline and metformin were significantly decreased in Oct1/2 DKO mice alone. These are the first to suggest that Oct1 might be involved in secretory transfer of substrate drugs into milk.
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Affiliation(s)
- Naoki Ito
- Department of Pediatrics, The University of Tokyo Hospital, Faculty of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo, 113-8655, Japan
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Shennan DB, Boyd CAR. The functional and molecular entities underlying amino acid and peptide transport by the mammary gland under different physiological and pathological conditions. J Mammary Gland Biol Neoplasia 2014; 19:19-33. [PMID: 24158403 DOI: 10.1007/s10911-013-9305-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2013] [Accepted: 10/15/2013] [Indexed: 12/20/2022] Open
Abstract
This review describes the properties and regulation of the membrane transport proteins which supply the mammary gland with aminonitrogen to support metabolism under different physiological conditions (i.e. pregnancy, lactation and involution). Early studies focussed on characterising amino acid and peptide transport pathways with respect to substrate specificity, kinetics and hormonal regulation to allow a broad picture of the systems within the gland to be established. Recent investigations have concentrated on identifying the individual transporters at the molecular level (i.e. mRNA and protein). Many of the latter studies have identified the molecular correlates of the transport systems uncovered in the earlier functional investigations but in turn have also highlighted the need for more amino acid transport studies to be performed. The transporters function as either cotransporters and exchangers (or both) and act in a coordinated and regulated fashion to support the metabolic needs of the gland. However, it is apparent that a physiological role for a number of the transport proteins has yet to be elucidated. This article highlights the many gaps in our knowledge regarding the precise cellular location of a number of amino acid transporters within the gland. We also describe the role of amino acid transport in mammary cell volume regulation. Finally, the important role that individual mammary transport proteins may have in the growth and proliferation of mammary tumours is discussed.
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Affiliation(s)
- D B Shennan
- Brasenose College, 39 Caerlaverock Road, Prestwick, UK,
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Xu Q, Wang C, Meng Q, Liu Q, Sun P, Sun H, Guo X, Liu K. The oligopeptide transporter 2-mediated reabsorption of entecavir in rat kidney. Eur J Pharm Sci 2014; 52:41-7. [DOI: 10.1016/j.ejps.2013.10.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2013] [Revised: 09/16/2013] [Accepted: 10/16/2013] [Indexed: 11/17/2022]
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Nadeem Q, Can D, Shen Y, Felber M, Mahmood Z, Alberto R. Synthesis of tripeptide derivatized cyclopentadienyl complexes of technetium and rhenium as radiopharmaceutical probes. Org Biomol Chem 2014; 12:1966-74. [DOI: 10.1039/c3ob41866a] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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Li L, Wang D, Zhang X, Song X, Ma X, Hu Z. [Expression of PEPT2 mRNA in lung tissue of rats with pulmonary fibrosis]. ZHONGGUO FEI AI ZA ZHI = CHINESE JOURNAL OF LUNG CANCER 2013; 16:541-6. [PMID: 24113008 PMCID: PMC6015171 DOI: 10.3779/j.issn.1009-3419.2013.10.08] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
背景与目的 肺纤维化是肺癌放化疗后的常见病理改变,是阻碍药物转运到肺部的关键因素之一,肽转运载体已经成为合理设计肽和肽类药物的靶标,本研究旨在探讨肽转运载体2(peptide transporter 2, PEPT2)mRNA在肺纤维化大鼠肺组织中的表达。 方法 健康SD大鼠50只,随机分为5组。博莱霉素(bleomycin, BLM)7 d、14 d、28 d组:气管内一次性滴入博莱霉素溶液复制肺纤维化大鼠模型,分别于给药后7 d、14 d和28 d放血处死;生理盐水组滴入等量生理盐水,于14 d放血处死;正常组不做任何处理。各组取肺组织,光镜观察组织病理变化;检测样本羟脯氨酸含量;半定量RT-PCR检测肺组织PEPT2 mRNA表达。 结果 BLM 7 d组大鼠肺组织呈急性炎症性改变,无纤维增生;BLM 14 d组和28 d组大鼠肺组织均有纤维化改变,以28 d组最为明显。BLM 7 d组肺组织羟脯氨酸含量与正常对照组和生理盐水组相比无统计学差异(P > 0.05);14 d组和28 d组大鼠肺组织羟脯氨酸含量均高于正常对照组和生理盐水组(P < 0.05)。各组肺组织PEPT2 mRNA的相对表达量无统计学差异(P > 0.05)。 结论 PEPT2 mRNA在博莱霉素致肺纤维化大鼠肺组织表达水平无明显变化,PEPT2可能是设计肺纤维化的新型肽类药物靶标之一。
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Affiliation(s)
- Li Li
- Department of Bio-immunical Therapy, the Third Affiliated Hospital of Kunming Medical University, Kunming 650118, China
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Sun D, Tan F, Fang D, Wang Y, Zeng S, Jiang H. Expression of proton-coupled oligopeptide transporter (POTs) in prostate of mice and patients with benign prostatic hyperplasia (BPH) and prostate cancer (PCa). Prostate 2013; 73:287-95. [PMID: 22887093 DOI: 10.1002/pros.22568] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2012] [Accepted: 06/03/2012] [Indexed: 12/19/2022]
Abstract
BACKGROUND Proton-coupled oligopeptide transporters (POTs) serve as integral membrane protein for the cellular uptake of di/tripeptide. Prostate has a large requirement of nutriment for its function to produce and secrete prostatic fluid. Besides, prostate suffered from limited therapy effect of drug treatment. Thus present study was performed to evaluate the expression of POTs in prostate of mice and human with the aim to provide information for potential role of POTs in absorption of nutriment and peptidomimetic drugs in prostate. METHODS Quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot methods were applied to study the mRNA, protein expression of POTs in prostate, human prostate cancer cells (PC-3), and human prostate epithelial cells (RWPE-1). RESULTS qRT-PCR study showed different characteristic of POTs mRNA expression in mouse prostate. Among these transporters, protein expression of PepT2 was detected and increasing during the development of mouse prostate, while PepT1, PHT1, and PHT2 protein was not detected. Furthermore, different characteristic of regulation by inflammation on POTs mRNA expression was found in RWPE-1 and PC-3. In addition, mRNA expression of PepT2 and PHT1 in prostate of patients with PCa was demonstrated be lower compared with BPH. CONCLUSIONS These findings provide the first evidence for the expression of POTs in prostate of mice and patients with BPH or PCa and suggest that POTs are likely to play a role in the transport of di/tripeptides and peptidomimetics in prostate.
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Affiliation(s)
- Dongli Sun
- Department of Pharmaceutical Analysis and Drug Metabolism, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China
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Expression Profile of Drug and Nutrient Absorption Related Genes in Madin-Darby Canine Kidney (MDCK) Cells Grown under Differentiation Conditions. Pharmaceutics 2012; 4:314-33. [PMID: 24300234 PMCID: PMC3834914 DOI: 10.3390/pharmaceutics4020314] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2012] [Revised: 05/15/2012] [Accepted: 06/06/2012] [Indexed: 11/17/2022] Open
Abstract
The expression levels of genes involved in drug and nutrient absorption were evaluated in the Madin-Darby Canine Kidney (MDCK) in vitro drug absorption model. MDCK cells were grown on plastic surfaces (for 3 days) or on Transwell® membranes (for 3, 5, 7, and 9 days). The expression profile of genes including ABC transporters, SLC transporters, and cytochrome P450 (CYP) enzymes was determined using the Affymetrix® Canine GeneChip®. Expression of genes whose probe sets passed a stringent confirmation process was examined. Expression of a few transporter (MDR1, PEPT1 and PEPT2) genes in MDCK cells was confirmed by RT-PCR. The overall gene expression profile was strongly influenced by the type of support the cells were grown on. After 3 days of growth, expression of 28% of the genes was statistically different (1.5-fold cutoff, p < 0.05) between the cells grown on plastic and Transwell® membranes. When cells were differentiated on Transwell® membranes, large changes in gene expression profile were observed during the early stages, which then stabilized after 5–7 days. Only a small number of genes encoding drug absorption related SLC, ABC, and CYP were detected in MDCK cells, and most of them exhibited low hybridization signals. Results from this study provide valuable reference information on endogenous gene expression in MDCK cells that could assist in design of drug-transporter and/or drug-enzyme interaction studies, and help interpret the contributions of various transporters and metabolic enzymes in studies with MDCK cells.
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Cano-Soldado P, Pastor-Anglada M. Transporters that translocate nucleosides and structural similar drugs: structural requirements for substrate recognition. Med Res Rev 2011; 32:428-57. [DOI: 10.1002/med.20221] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Affiliation(s)
- Pedro Cano-Soldado
- Departament de Bioquímica i Biologia Molecular; Institut de Biomedicina de la Universitat de Barcelona (IBUB); Universitat de Barcelona and CIBER EHD; Barcelona Spain
| | - Marçal Pastor-Anglada
- Departament de Bioquímica i Biologia Molecular; Institut de Biomedicina de la Universitat de Barcelona (IBUB); Universitat de Barcelona and CIBER EHD; Barcelona Spain
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30
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Liu R, Tang AMY, Tan YL, Limenta LMG, Lee EJD. Effects of Sodium Bicarbonate and Ammonium Chloride Pre-treatments on PEPT2 (SLC15A2) Mediated Renal Clearance of Cephalexin in Healthy Subjects. Drug Metab Pharmacokinet 2011; 26:87-93. [DOI: 10.2133/dmpk.dmpk-10-rg-039] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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31
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Bosquillon C. Drug transporters in the lung--do they play a role in the biopharmaceutics of inhaled drugs? J Pharm Sci 2010; 99:2240-55. [PMID: 19950388 DOI: 10.1002/jps.21995] [Citation(s) in RCA: 109] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The role of transporters in drug absorption, distribution and elimination processes as well as in drug-drug interactions is increasingly being recognised. Although the lungs express high levels of both efflux and uptake drug transporters, little is known of the implications for the biopharmaceutics of inhaled drugs. The current knowledge of the expression, localisation and functionality of drug transporters in the pulmonary tissue and the few studies that have looked at their impact on pulmonary drug absorption is extensively reviewed. The emphasis is on transporters most likely to affect the disposition of inhaled drugs: (1) the ATP-binding cassette (ABC) superfamily which includes the efflux pumps P-glycoprotein (P-gp), multidrug resistance associated proteins (MRPs), breast cancer resistance protein (BCRP) and (2) the solute-linked carrier (SLC and SLCO) superfamily to which belong the organic cation transporter (OCT) family, the peptide transporter (PEPT) family, the organic anion transporter (OAT) family and the organic anion transporting polypeptide (OATP) family. Whenever available, expression and localisation in the intact human tissue are compared with those in animal lungs and respiratory epithelial cell models in vitro. The influence of lung diseases or exogenous agents on transporter expression is also mentioned.
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Affiliation(s)
- Cynthia Bosquillon
- Centre for Biomolecular Sciences, School of Pharmacy, University of Nottingham, University Park, Nottingham NG72RD, United Kingdom.
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32
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Klaassen CD, Aleksunes LM. Xenobiotic, bile acid, and cholesterol transporters: function and regulation. Pharmacol Rev 2010; 62:1-96. [PMID: 20103563 PMCID: PMC2835398 DOI: 10.1124/pr.109.002014] [Citation(s) in RCA: 563] [Impact Index Per Article: 40.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Transporters influence the disposition of chemicals within the body by participating in absorption, distribution, and elimination. Transporters of the solute carrier family (SLC) comprise a variety of proteins, including organic cation transporters (OCT) 1 to 3, organic cation/carnitine transporters (OCTN) 1 to 3, organic anion transporters (OAT) 1 to 7, various organic anion transporting polypeptide isoforms, sodium taurocholate cotransporting polypeptide, apical sodium-dependent bile acid transporter, peptide transporters (PEPT) 1 and 2, concentrative nucleoside transporters (CNT) 1 to 3, equilibrative nucleoside transporter (ENT) 1 to 3, and multidrug and toxin extrusion transporters (MATE) 1 and 2, which mediate the uptake (except MATEs) of organic anions and cations as well as peptides and nucleosides. Efflux transporters of the ATP-binding cassette superfamily, such as ATP-binding cassette transporter A1 (ABCA1), multidrug resistance proteins (MDR) 1 and 2, bile salt export pump, multidrug resistance-associated proteins (MRP) 1 to 9, breast cancer resistance protein, and ATP-binding cassette subfamily G members 5 and 8, are responsible for the unidirectional export of endogenous and exogenous substances. Other efflux transporters [ATPase copper-transporting beta polypeptide (ATP7B) and ATPase class I type 8B member 1 (ATP8B1) as well as organic solute transporters (OST) alpha and beta] also play major roles in the transport of some endogenous chemicals across biological membranes. This review article provides a comprehensive overview of these transporters (both rodent and human) with regard to tissue distribution, subcellular localization, and substrate preferences. Because uptake and efflux transporters are expressed in multiple cell types, the roles of transporters in a variety of tissues, including the liver, kidneys, intestine, brain, heart, placenta, mammary glands, immune cells, and testes are discussed. Attention is also placed upon a variety of regulatory factors that influence transporter expression and function, including transcriptional activation and post-translational modifications as well as subcellular trafficking. Sex differences, ontogeny, and pharmacological and toxicological regulation of transporters are also addressed. Transporters are important transmembrane proteins that mediate the cellular entry and exit of a wide range of substrates throughout the body and thereby play important roles in human physiology, pharmacology, pathology, and toxicology.
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Affiliation(s)
- Curtis D Klaassen
- Department of Pharmacology, Toxicology, and Therapeutics, University of Kansas Medical Center, 3901 Rainbow Blvd., Kansas City, KS 66160-7417, USA.
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Gilchrist SE, Alcorn J. Lactation stage-dependent expression of transporters in rat whole mammary gland and primary mammary epithelial organoids. Fundam Clin Pharmacol 2009; 24:205-14. [PMID: 19702690 DOI: 10.1111/j.1472-8206.2009.00760.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Since solute carrier (SLC) and ATP-binding cassette (ABC) transporters play pivotal roles in the transport of both nutrients and drugs into breast milk, drug-nutrient transport interactions at the lactating mammary gland are possible. Our purpose was to characterize lactation stage-dependent changes in transporter expression in rat mammary gland and isolated mammary epithelial organoids (MEO) to provide additional insight for the safe use of maternal medications during breastfeeding. We used quantitative reverse transcription-polymerase chain reaction to assess the temporal expression patterns of SLC and ABC transporters in rat mammary gland and isolated MEO at different stages of lactation. In whole mammary gland five distinct patterns of expression emerged relative to late gestation: (i) decreasing throughout lactation (Mdr1a, Mdr1b, Mrp1, Octn2, Ent2, Ent3, Ncbt2, Mtx1); (ii) prominent increase in early lactation, which may remain elevated or decline with advancing lactation (Octn1, Cnt2, Cnt3, Ent1, Pept1, Pept2); (iii) constant but decreasing later in lactation (Octn3, Dmt1); (iv) increasing until mid-to-late lactation (Oct1, Cnt1); and (v) prominent increase late in lactation (Ncbt1). In isolated MEO (an enriched source of mammary epithelial cells) major differences in expression patterns were noted for Octn3, Ncbt1, and Mtx1, but otherwise were reasonably similar with the whole mammary gland. In conclusion our study augments existing data on transporter expression in the lactating mammary gland. These data should facilitate investigations into lactation-stage dependent changes in drug or nutrient milk-to-serum concentration ratios, the potential for drug- or disease-transporter interactions, and mechanistic studies of transporter function in the lactating mammary gland.
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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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35
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Jappar D, Hu Y, Keep RF, Smith DE. Transport mechanisms of carnosine in SKPT cells: contribution of apical and basolateral membrane transporters. Pharm Res 2008; 26:172-81. [PMID: 18820998 DOI: 10.1007/s11095-008-9726-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2008] [Accepted: 09/08/2008] [Indexed: 10/21/2022]
Abstract
PURPOSE The aim of this study was to investigate the transport properties of carnosine in kidney using SKPT cell cultures as a model of proximal tubular transport, and to isolate the functional activities of renal apical and basolateral transporters in this process. METHODS The membrane transport kinetics of 10 microM [3H]carnosine was studied in SKPT cells as a function of time, pH, potential inhibitors and substrate concentration. A cellular compartment model was constructed in which the influx, efflux and transepithelial clearances of carnosine were determined. Peptide transporter expression was probed by RT-PCR. RESULTS Carnosine uptake was 15-fold greater from the apical than basolateral surface of SKPT cells. However, the apical-to-basolateral transepithelial transport of carnosine was severely rate-limited by its cellular efflux across the basolateral membrane. The high-affinity, proton-dependence, concentration-dependence and inhibitor specificity of carnosine supports the contention that PEPT2 is responsible for its apical uptake. In contrast, the basolateral transporter is saturable, inhibited by PEPT2 substrates but non-concentrative, thereby, suggesting a facilitative carrier. CONCLUSIONS Carnosine is expected to have a substantial cellular accumulation in kidney but minimal tubular reabsorption in blood because of its high influx clearance across apical membranes by PEPT2 and very low efflux clearance across basolateral membranes.
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Affiliation(s)
- Dilara Jappar
- Department of Pharmaceutical Sciences, University of Michigan, Ann Arbor, Michigan 48109, USA
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Poole DC, Brown MD, Hudlicka O. Counterpoint: There is not capillary recruitment in active skeletal muscle during exercise. J Appl Physiol (1985) 2008; 104:891-3; discussion 893-4. [PMID: 18326874 DOI: 10.1152/japplphysiol.00779.2007a] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Affiliation(s)
- David C Poole
- Department of Kinesiology, Kansas State University, KS, USA.
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Biegel A, Knütter I, Hartrodt B, Gebauer S, Theis S, Luckner P, Kottra G, Rastetter M, Zebisch K, Thondorf I, Daniel H, Neubert K, Brandsch M. The renal type H+/peptide symporter PEPT2: structure-affinity relationships. Amino Acids 2006; 31:137-56. [PMID: 16868651 DOI: 10.1007/s00726-006-0331-0] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2005] [Accepted: 01/04/2006] [Indexed: 10/24/2022]
Abstract
The H(+)/peptide cotransporter PEPT2 is expressed in a variety of organs including kidney, lung, brain, mammary gland, and eye. PEPT2 substrates are di- and tripeptides as well as peptidomimetics, such as beta-lactam antibiotics. Due to the presence of PEPT2 at the bronchial epithelium, the aerosolic administration of peptide-like drugs might play a major role in future treatment of various pulmonary and systemic diseases. Moreover, PEPT2 has a significant influence on the in vivo disposition and half-life time of peptide-like drugs within the body, particularly in kidney and brain. PEPT2 is known to have similar but not identical structural requirements for substrate recognition and transport compared to PEPT1, its intestinal counterpart. In this review we compiled available affinity constants of 352 compounds, measured at different mammalian tissues and expression systems and compare the data whenever possible with those of PEPT1.
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Affiliation(s)
- A Biegel
- Institute of Biochemistry, Department of Biochemistry/Biotechnology, Martin-Luther-University Halle-Wittenberg, Halle, Germany
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Shimakura J, Terada T, Shimada Y, Katsura T, Inui KI. The transcription factor Cdx2 regulates the intestine-specific expression of human peptide transporter 1 through functional interaction with Sp1. Biochem Pharmacol 2006; 71:1581-8. [PMID: 16616718 DOI: 10.1016/j.bcp.2006.03.001] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2006] [Revised: 03/02/2006] [Accepted: 03/02/2006] [Indexed: 01/12/2023]
Abstract
H(+)/peptide cotransporter 1 (PEPT1, SLC15A1) localized at the brush-border membranes of intestinal epithelial cells plays important roles in the intestinal absorption of small peptides and a variety of peptidemimetic drugs. We previously demonstrated that transcription factor Sp1 functions as a basal transcriptional regulator of human PEPT1. However, the factor responsible for the intestine-specific expression of PEPT1 remains unknown. In the present study, we investigated the effect of the intestinal transcription factors on the transcription of the PEPT1 gene and found that only Cdx2 markedly trans-activated the PEPT1 promoter. However, the promoter region responsible for this effect lacked a typical Cdx2-binding sequence, but instead, possessed some Sp1-binding sites. In vitro experiments using Caco-2 cells showed that (1) mutation of the Sp1-binding site diminished the effect of Cdx2, (2) co-expression of Cdx2 and Sp1 synergistically trans-activated the PEPT1 promoter and (3) Sp1 protein was immunoprecipitated with Cdx2 protein. These results raise the possibility that Cdx2 modulates the PEPT1 promoter by interaction with Sp1. The significance of Cdx2 in vivo for PEPT1 regulation was shown by the determination of mRNA levels of Cdx2 and PEPT1 in human tissue. In gastric samples, some with intestinal metaplasia, the levels of PEPT1 and Cdx2 mRNA were highly correlated. Taken together, the present study suggests that Cdx2 plays a key role in the transcriptional regulation of the intestine-specific expression of PEPT1, possibly through interaction with Sp1.
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Affiliation(s)
- Jin Shimakura
- Department of Pharmacy, Kyoto University Hospital, Faculty of Medicine, Kyoto University, Sakyo-ku, Kyoto 606-8507, Japan
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Groneberg DA, Paul H, Welte T. Novel strategies of aerosolic pharmacotherapy. ACTA ACUST UNITED AC 2006; 57 Suppl 2:49-53. [PMID: 16580826 DOI: 10.1016/j.etp.2006.02.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2005] [Accepted: 02/16/2006] [Indexed: 11/19/2022]
Abstract
The pulmonary administration of drugs plays a crucial role in the management of various respiratory and systemic diseases. While the cellular properties of airway epithelial cells offer a great potential to deliver drugs into the lungs or the circulation, only little is known about the exact transport pathways. Recently, the high-affinity proton-coupled drug and peptide transporter PEPT2 was identified in the human respiratory tract. The expression of transporter mRNA and protein was localized to the airway epithelium and alveolar type II pneumocytes. In addition, transport studies revealed transporter-mediated uptake of substrates into epithelial cells indicating that the transporter is the molecular basis for the transport of peptides and peptidomimetic drugs in pulmonary epithelial cells. Since genotype analysis revealed no significant differences amongst different transporter genotypes concerning expression and function, the transporter displays an interesting novel target for pulmonary delivery of drugs.
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Affiliation(s)
- David A Groneberg
- Departmnt of Respiratory Medicine, Hannover Medical School, Carl-Neuberg-Strasse 1, 30625 Hannover, Germany.
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Groneberg DA, Rabe KF, Fischer A. Novel concepts of neuropeptide-based drug therapy: vasoactive intestinal polypeptide and its receptors. Eur J Pharmacol 2006; 533:182-94. [PMID: 16473346 DOI: 10.1016/j.ejphar.2005.12.055] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/13/2005] [Indexed: 11/26/2022]
Abstract
Chronic inflammatory airway diseases such as bronchial asthma or chronic obstructive pulmonary disease (COPD) are major contributors to the global burden of disease. Although inflammatory cells play the central role in the pathogenesis of the diseases, recent observations indicate that also resident respiratory cells represent important targets for pulmonary drug development. Especially targeting airway neuromediators offers a possible mechanism by which respiratory diseases may be treated in the future. Among numerous peptide mediators such as tachykinins, calcitonin gene-related peptide, neurotrophins or opioids, vasoactive intestinal polypeptide (VIP) is one of the most abundant molecules found in the respiratory tract. In human airways, it influences many respiratory functions via the receptors VPAC1, VPAC2 and PAC1. VIP-expressing nerve fibers are present in the tracheobronchial smooth muscle layer, submucosal glands and in the walls of pulmonary and bronchial arteries and veins. Next to its strong bronchodilator effects, VIP potently relaxes pulmonary vessels, and plays a pivotal role in the mediation of immune mechanisms. A therapy utilizing the respiratory effects of VIP would offer potential benefits in the treatment of obstructive and inflammatory diseases and long acting VIP-based synthetic non-peptide compounds may represent a novel target for drug development.
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Affiliation(s)
- David A Groneberg
- Department of Respiratory Medicine, Hannover Medical School, Hannover, Germany.
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Klapper M, Daniel H, Döring F. Cytosolic COOH terminus of the peptide transporter PEPT2 is involved in apical membrane localization of the protein. Am J Physiol Cell Physiol 2006; 290:C472-83. [PMID: 16107500 DOI: 10.1152/ajpcell.00508.2004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The peptide transporter PEPT2 is a polytopic transmembrane protein that mediates the cellular uptake of di- and tripeptides and a variety of peptidomimetics. It is widely expressed in mammalian tissues, including kidney, lung, mammary gland, choroid plexus, and glia cells. In renal tubular cells, PEPT2 is exclusively found at the apical membrane. The molecular mechanisms underlying this polarized expression and targeting to the brush-border membrane are not known. We have explored the role of the 36 COOH-terminal amino acid residues in PEPT2 trafficking and apical expression. EGFP-tagged PEPT2 wild-type transporter and various truncated and mutant proteins were expressed in the polarized proximal tubule cell lines SKPT and OK, and the cellular distribution of the fusion proteins was assessed using confocal microscopy. Whereas deletion of the last seven amino acids (delC7) did not alter PEPT2 surface expression, deletion of the next residue (delC8) or up to 30 terminal amino acids resulted in impaired apical expression and distinct accumulation of mutant proteins in endosomal and lysosomal vesicles. Truncation of more amino acids (delC36) containing tyrosine-based motifs led to a rather diffuse intracellular distribution pattern. Mutations introduced at isoleucine-720 (I720A) and leucine-722 (I722A) also caused an impaired surface appearance. Internalization assays revealed a higher endocytotic rate of the PEPT2 mutants I720A, L722A, and delC36. Our data suggest that a three-amino acid stretch (INL) and tyrosine-based motifs within the COOH tail of PEPT2 are involved in PEPT2's apical membrane localization and membrane steady-state level.
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Affiliation(s)
- Maja Klapper
- Research Group Molecular Nutrition, Univ. of Kiel, Germany
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Cavalli C, Teng C, Battaglia FC, Bevilacqua G. Free sugar and sugar alcohol concentrations in human breast milk. J Pediatr Gastroenterol Nutr 2006; 42:215-21. [PMID: 16456418 DOI: 10.1097/01.mpg.0000189341.38634.77] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
OBJECTIVES The goal was to determine the free sugars and polyols in human breast milk, both term and preterm, for comparison with formula milks. METHODS Methodology was developed for the measurement of the free sugars and polyols in breast milk. There were 16 samples collected from women who delivered at term and 17 samples from women delivering preterm. For purposes of comparison, samples were also collected from four commercial formulas for term infants and eight from commercial formulas for preterm infants as well as one sample of cows' milk. All samples were frozen immediately and analyzed by high-performance liquid chromatography techniques. RESULTS Except for lactose concentrations, no significant differences were detected for all other sugars and polyols between term and preterm breast milk samples. Within breast milk samples, two patterns emerged, with one group containing additional elution peaks for compounds not yet identified. A second group did not contain these compounds. There were a number of significant differences between breast milk and formulas, particularly for inositol, glycerol, glucose, and galactose. All milks contained significant concentrations of mannose. CONCLUSIONS There are no significant differences among breast milk samples for free sugar and polyol concentrations except lactose. However, some milk contains additional peaks that could be of dietary or genetic origin. Formula milk has relatively high concentrations of glucose and galactose compared with breast milk, suggesting some lactose hydrolysis.
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Affiliation(s)
- Claudio Cavalli
- Department of Neonatology, University of Parma, Parma, Italy
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Döring F, Schmitt R, Bernhardt WM, Klapper M, Bachmann S, Daniel H, Groneberg DA. Hypothyroidism induces expression of the peptide transporter PEPT2. Biol Chem 2005; 386:785-90. [PMID: 16201874 DOI: 10.1515/bc.2005.092] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
The kidney is a target organ for thyroid hormone action and a variety of renal transport processes are altered in response to impaired thyroid functions. To investigate the effect of thyroid hormone on the expression of the renal proximal tubular high-affinity-type H+-peptide cotransporter (PEPT2) in rats, hypothyroidism was induced in animals by administration of methimazole (0.05%) via drinking water. After 7 weeks of treatment, hypothyroidism was confirmed by determining serum free T3 and free T4 concentrations. Northern blotting was used to examine the expression of PEPT2 mRNA in kidney tissues from hypothyroid rats compared to control rats. Hypothyroidism resulted in an increased level of total renal PEPT2 mRNA (121.1±3.3% vs. control 100±2.8%; p=0.008). The mRNA results were confirmed by immuno-blotting, which demonstrated significantly increased protein levels (162% vs. control 100%; p<0.01). Immunohistochemistry also revealed increased PEPT2 protein levels in the proximal tubules of treated compared to non-treated rats. In summary, PEPT2 is the first proximal tubule transporter protein that shows increased expression in states of hypothyreosis. As PEPT2 reabsorbs filtered di- and tripeptides and peptide-like drugs, the present findings may have important implications in nutritional amino acid homeostasis and for drug dynamics in states of altered thyroid function.
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Affiliation(s)
- Frank Döring
- Otto-Heubner-Center, Biomedical Research Center, Charité - Medical School of the Free University and Humboldt-University, D-13353 Berlin, Germany
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Nielsen CU, Brodin B, Jørgensen FS, Frokjaer S, Steffansen B. Human peptide transporters: therapeutic applications. Expert Opin Ther Pat 2005. [DOI: 10.1517/13543776.12.9.1329] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Bravo SA, Nielsen CU, Frokjaer S, Brodin B. Characterization of rPEPT2-Mediated Gly-Sar Transport Parameters in the Rat Kidney Proximal Tubule Cell Line SKPT-0193 cl.2 Cultured in Basic Growth Media. Mol Pharm 2005; 2:98-108. [PMID: 15804184 DOI: 10.1021/mp049892q] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The rat proximal kidney tubule cell line SKPT-0193 cl.2 (SKPT) expresses the di-/tripeptide transporter PEPT2 (rPEPT2) and has been used to study PEPT2-mediated transport. Traditionally, SKPT cells have been cultured in growth media supplemented with epidermal growth factor (EGF), apotransferrin, dexamethasone, and insulin. It was recently demonstrated that omission of EGF from the culture media caused a drastic increase in the expression of rPEPT2. The hypothesis was therefore that the SKPT cell line might be able to differentiate and express rPEPT2 in the absence of the four agonists traditionally added. The aim of the study was thus to characterize Gly-Sar transport parameters in SKPT cells cultured in basic growth media (conventional media without added agonists). Morphology was studied using confocal laser scanning microscopy (CLSM) and immunohistochemistry. Monolayer integrity was evaluated using transepithelial electrical resistance (TEER) measurements and [(3)H]-mannitol permeabilities. Di-/tripeptide transporter activity was studied using [(14)C]-glycylsarcosine ([(14)C]-Gly-Sar). SKPT cells grown in basic media for 4 days formed confluent monolayers with a TEER of 5.03 +/- 0.33 kOmega.cm(2) (n = 5). Apical Gly-Sar uptake peaked after 3-6 days in culture. Uptake at day 4 was 5.89 +/- 0.30 pmol.cm(-2).min(-1) (n = 3). Di-/tripeptide uptake displayed an optimum at approximately pH 6. Affinity values for cephalexin, kyotorphin, and delta-aminolevulinic acid were comparable to those obtained in other PEPT2-expressing model systems. It can be concluded that SKPT cells grown in the absence of the agonists traditionally added to the culture media retain all necessary properties for PEPT2-mediated peptide uptake studies. Furthermore, the absence of the agonists might facilitate studies of hormonal regulation of PEPT2 expression and transport activity.
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Affiliation(s)
- Silvina A Bravo
- Molecular Biopharmaceutics, Department of Pharmaceutics, The Danish University of Pharmaceutical Sciences, Universitetsparken 2, DK-2100 Copenhagen, Denmark
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Groneberg DA, Hilgenfeld R, Zabel P. Molecular mechanisms of severe acute respiratory syndrome (SARS). Respir Res 2005; 6:8. [PMID: 15661082 PMCID: PMC548145 DOI: 10.1186/1465-9921-6-8] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2004] [Accepted: 01/20/2005] [Indexed: 02/08/2023] Open
Abstract
Severe acute respiratory syndrome (SARS) is a new infectious disease caused by a novel coronavirus that leads to deleterious pulmonary pathological features. Due to its high morbidity and mortality and widespread occurrence, SARS has evolved as an important respiratory disease which may be encountered everywhere in the world. The virus was identified as the causative agent of SARS due to the efforts of a WHO-led laboratory network. The potential mutability of the SARS-CoV genome may lead to new SARS outbreaks and several regions of the viral genomes open reading frames have been identified which may contribute to the severe virulence of the virus. With regard to the pathogenesis of SARS, several mechanisms involving both direct effects on target cells and indirect effects via the immune system may exist. Vaccination would offer the most attractive approach to prevent new epidemics of SARS, but the development of vaccines is difficult due to missing data on the role of immune system-virus interactions and the potential mutability of the virus. Even in a situation of no new infections, SARS remains a major health hazard, as new epidemics may arise. Therefore, further experimental and clinical research is required to control the disease.
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Affiliation(s)
- David A Groneberg
- Pneumology and Immunology, Otto-Heubner-Centre, Charité School of Medicine, Free University and Humboldt-University, D-13353 Berlin, Germany
| | - Rolf Hilgenfeld
- Institute of Biochemistry, University of Lübeck, D-23538 Lübeck, Germany
| | - Peter Zabel
- Division of Clinical Infectiology and Immunology, Department of Medicine, Research Center Borstel, D-23845 Borstel, Germany
- Division of Thoracic Medicine, Department of Medicine, University of Lübeck, D-23538 Lübeck, Germany
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Groneberg DA, Peiser C, Eynott PR, Welker P, Erbes R, Witt C, Chung KF, Fischer A. Transcriptional down-regulation of neurotrophin-3 in chronic obstructive pulmonary disease. Biol Chem 2005; 386:53-9. [PMID: 15843147 DOI: 10.1515/bc.2005.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Chronic obstructive pulmonary disease (COPD) leads to progressive development of airflow limitation and is characterised by cough, mucus hypersecretion and inflammatory changes. These characteristic features of the disease may be modulated by neural mediators such as neurotrophins (NT). Here we examined the expression and transcriptional regulation of neurotrophins in bronchial biopsies of COPD patients and compared the data to control biopsies. Histology revealed characteristic changes in the COPD tissues, including remodelling of the epithelial lining. RT-PCR demonstrated the mRNA expression of neurotrophins in all biopsies. Immunohistochemistry confirmed the expression of different proteins. To assess changes in the transcriptional expression level, quantitative real-time PCR was carried out and revealed differential mRNA expression of neurotrophins, with marked down-regulation of NT-3 mRNA expression and constant levels of nerve growth factor (NGF), brain-derived nerve factor (BDNF), and NT-4/5 mRNA expression. The present data on neurotrophin-specific transcriptional down-regulation of NT-3 in human COPD indicate a pathophysiological role for neurotrophins in COPD.
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Affiliation(s)
- David A Groneberg
- Otto-Heubner-Centre, Pneumology and Immunology, Free University Berlin and Humboldt-University, D-13353 Berlin, Germany.
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Nielsen HM, Aemisegger C, Burmeister G, Schuchter U, Gander B. Effect of Oil-in-Water Emulsions on 5-Aminolevulinic Acid Uptake and Metabolism to PpIX in Cultured MCF-7 Cells. Pharm Res 2004; 21:2253-60. [PMID: 15648257 DOI: 10.1007/s11095-004-7678-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
PURPOSE To identify the optimal vehicle for fast and efficient cellular production of the photosensitizer, protoporphyrin IX (PpIX), upon administration of 5-aminolevulinic acid (ALA). METHODS ALA in various oil/water o/w emulsions was applied to the human mammary epithelial cell line (MCF-7) cultured in microplates. Upon incubation for 14 h, the accumulated amount of PpIX was determined by fluorescence spectroscopy. Variables such as the pH and concentration of the emulsions, the temperature and duration of incubation were examined along with the importance of ALA concentration and the presence of endocytosis inhibitors. RESULTS An increase in the amount of produced PpIX was observed with an increase in extracellular pH, incubation temperature, and ALA concentration. A saturable mechanism of PpIX accumulation was evident, mainly as a result of the uptake mechanism for ALA. Some of the o/w emulsions increased the amount of intracellular PpIX, and the results indicated that this was not due to an increased k(m) of the extracellular ALA to intracellular PpIX conversion, but to the increased endocytotic uptake in the presence of the emulsions. In general, the increase in PpIX in the presence of emulsions relative to the control was more pronounced after 1 h as compared to after 2-4 h. CONCLUSIONS The formation of PpIX in MCF-7 cells exposed to ALA is improved by the presence of certain o/w emulsions, which could be explained by endocytosis.
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Affiliation(s)
- Hanne Mørck Nielsen
- Institute of Pharmaceutical Sciences, Swiss Federal Institute of Technology Zürich (ETH Zürich), Winterthurerstrasse 190, 8057 Zürich, Switzerland.
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Abstract
Neurogenic inflammation encompasses the release of neuropeptides from airway nerves leading to inflammatory effects. This neurogenic inflammatory response of the airways can be initiated by exogenous irritants such as cigarette smoke or gases and is characterized by a bi-directional linkage between airway nerves and airway inflammation. The event of neurogenic inflammation may participate in the development and progression of chronic inflammatory airway diseases such as allergic asthma or chronic obstructive pulmonary disease (COPD). The molecular mechanisms underlying neurogenic inflammation are orchestrated by a large number of neuropeptides including tachykinins such as substance P and neurokinin A, or calcitonin gene-related peptide. Also, other biologically active peptides such as neuropeptide tyrosine, vasoactive intestinal polypeptide or endogenous opioids may modulate the inflammatory response and recently, novel tachykinins such as virokinin and hemokinins were identified. Whereas the different aspects of neurogenic inflammation have been studied in detail in laboratory animal models, only little is known about the role of airway neurogenic inflammation in human diseases. However, different functional properties of airway nerves may be used as targets for future therapeutic strategies and recent clinical data indicates that novel dual receptor antagonists may be relevant new drugs for bronchial asthma or COPD.
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Affiliation(s)
- D A Groneberg
- Otto-Heubner-Centre, Pneumology and Immunology, Charité School of Medicine, Free University Berlin and Humboldt-University Berlin, Berlin, Germany
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