1
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Khare S, Villalba MI, Canul-Tec JC, Cajiao AB, Kumar A, Backovic M, Rey FA, Pardon E, Steyaert J, Perez C, Reyes N. Receptor-recognition and antiviral mechanisms of retrovirus-derived human proteins. Nat Struct Mol Biol 2024; 31:1368-1376. [PMID: 38671230 DOI: 10.1038/s41594-024-01295-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Accepted: 03/26/2024] [Indexed: 04/28/2024]
Abstract
Human syncytin-1 and suppressyn are cellular proteins of retroviral origin involved in cell-cell fusion events to establish the maternal-fetal interface in the placenta. In cell culture, they restrict infections from members of the largest interference group of vertebrate retroviruses, and are regarded as host immunity factors expressed during development. At the core of the syncytin-1 and suppressyn functions are poorly understood mechanisms to recognize a common cellular receptor, the membrane transporter ASCT2. Here, we present cryo-electron microscopy structures of human ASCT2 in complexes with the receptor-binding domains of syncytin-1 and suppressyn. Despite their evolutionary divergence, the two placental proteins occupy similar positions in ASCT2, and are stabilized by the formation of a hybrid β-sheet or 'clamp' with the receptor. Structural predictions of the receptor-binding domains of extant retroviruses indicate overlapping binding interfaces and clamping sites with ASCT2, revealing a competition mechanism between the placental proteins and the retroviruses. Our work uncovers a common ASCT2 recognition mechanism by a large group of endogenous and disease-causing retroviruses, and provides high-resolution views on how placental human proteins exert morphological and immunological functions.
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Affiliation(s)
- Shashank Khare
- Fundamental Microbiology and Pathogenicity Unit, CNRS, Université de Bordeaux, IECB, Bordeaux, France
| | - Miryam I Villalba
- Fundamental Microbiology and Pathogenicity Unit, CNRS, Université de Bordeaux, IECB, Bordeaux, France
| | - Juan C Canul-Tec
- Fundamental Microbiology and Pathogenicity Unit, CNRS, Université de Bordeaux, IECB, Bordeaux, France
| | | | - Anand Kumar
- Fundamental Microbiology and Pathogenicity Unit, CNRS, Université de Bordeaux, IECB, Bordeaux, France
| | - Marija Backovic
- Institut Pasteur, Université Paris Cité, CNRS UMR3569, Unité de Virologie Structurale, Paris, France
| | - Felix A Rey
- Institut Pasteur, Université Paris Cité, CNRS UMR3569, Unité de Virologie Structurale, Paris, France
| | - Els Pardon
- Structural Biology Brussels, Vrije Universiteit Brussel, VUB, Brussels, Belgium
- VIB-VUB Center for Structural Biology, VIB, Brussels, Belgium
| | - Jan Steyaert
- Structural Biology Brussels, Vrije Universiteit Brussel, VUB, Brussels, Belgium
- VIB-VUB Center for Structural Biology, VIB, Brussels, Belgium
| | - Camilo Perez
- Biozentrum, University of Basel, Basel, Switzerland.
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, USA.
| | - Nicolas Reyes
- Fundamental Microbiology and Pathogenicity Unit, CNRS, Université de Bordeaux, IECB, Bordeaux, France.
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2
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Borowska AM, Chiariello MG, Garaeva AA, Rheinberger J, Marrink SJ, Paulino C, Slotboom DJ. Structural basis of the obligatory exchange mode of human neutral amino acid transporter ASCT2. Nat Commun 2024; 15:6570. [PMID: 39095408 PMCID: PMC11297037 DOI: 10.1038/s41467-024-50888-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Accepted: 07/23/2024] [Indexed: 08/04/2024] Open
Abstract
ASCT2 is an obligate exchanger of neutral amino acids, contributing to cellular amino acid homeostasis. ASCT2 belongs to the same family (SLC1) as Excitatory Amino Acid Transporters (EAATs) that concentrate glutamate in the cytosol. The mechanism that makes ASCT2 an exchanger rather than a concentrator remains enigmatic. Here, we employ cryo-electron microscopy and molecular dynamics simulations to elucidate the structural basis of the exchange mechanism of ASCT2. We establish that ASCT2 binds three Na+ ions per transported substrate and visits a state that likely acts as checkpoint in preventing Na+ ion leakage, both features shared with EAATs. However, in contrast to EAATs, ASCT2 retains one Na+ ion even under Na+-depleted conditions. We demonstrate that ASCT2 cannot undergo the structural transition in TM7 that is essential for the concentrative transport cycle of EAATs. This structural rigidity and the high-affinity Na+ binding site effectively confine ASCT2 to an exchange mode.
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Affiliation(s)
- Anna M Borowska
- Faculty of Science and Engineering, Groningen Biomolecular Sciences and Biotechnology, Membrane Enzymology Group, University of Groningen, Groningen, the Netherlands
| | - Maria Gabriella Chiariello
- Faculty of Science and Engineering, Groningen Biomolecular Sciences and Biotechnology Institute, Molecular Dynamics Group, University of Groningen, Groningen, the Netherlands
| | - Alisa A Garaeva
- Faculty of Science and Engineering, Groningen Biomolecular Sciences and Biotechnology, Membrane Enzymology Group, University of Groningen, Groningen, the Netherlands
- Institute of Medical Microbiology, University of Zurich, Zurich, Switzerland
| | - Jan Rheinberger
- Faculty of Science and Engineering, Groningen Biomolecular Sciences and Biotechnology, Membrane Enzymology Group, University of Groningen, Groningen, the Netherlands
- Biochemistry Center Heidelberg, Heidelberg University, Heidelberg, Germany
| | - Siewert J Marrink
- Faculty of Science and Engineering, Groningen Biomolecular Sciences and Biotechnology Institute, Molecular Dynamics Group, University of Groningen, Groningen, the Netherlands
| | - Cristina Paulino
- Faculty of Science and Engineering, Groningen Biomolecular Sciences and Biotechnology, Membrane Enzymology Group, University of Groningen, Groningen, the Netherlands.
- Biochemistry Center Heidelberg, Heidelberg University, Heidelberg, Germany.
| | - Dirk J Slotboom
- Faculty of Science and Engineering, Groningen Biomolecular Sciences and Biotechnology, Membrane Enzymology Group, University of Groningen, Groningen, the Netherlands.
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3
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Hoff SE, Thomasen FE, Lindorff-Larsen K, Bonomi M. Accurate model and ensemble refinement using cryo-electron microscopy maps and Bayesian inference. PLoS Comput Biol 2024; 20:e1012180. [PMID: 39008528 PMCID: PMC11271924 DOI: 10.1371/journal.pcbi.1012180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2023] [Revised: 07/25/2024] [Accepted: 05/20/2024] [Indexed: 07/17/2024] Open
Abstract
Converting cryo-electron microscopy (cryo-EM) data into high-quality structural models is a challenging problem of outstanding importance. Current refinement methods often generate unbalanced models in which physico-chemical quality is sacrificed for excellent fit to the data. Furthermore, these techniques struggle to represent the conformational heterogeneity averaged out in low-resolution regions of density maps. Here we introduce EMMIVox, a Bayesian inference approach to determine single-structure models as well as structural ensembles from cryo-EM maps. EMMIVox automatically balances experimental information with accurate physico-chemical models of the system and the surrounding environment, including waters, lipids, and ions. Explicit treatment of data correlation and noise as well as inference of accurate B-factors enable determination of structural models and ensembles with both excellent fit to the data and high stereochemical quality, thus outperforming state-of-the-art refinement techniques. EMMIVox represents a flexible approach to determine high-quality structural models that will contribute to advancing our understanding of the molecular mechanisms underlying biological functions.
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Affiliation(s)
- Samuel E. Hoff
- Institut Pasteur, Université Paris Cité, CNRS UMR 3528, Computational Structural Biology Unit, Paris, France
| | - F. Emil Thomasen
- Structural Biology and NMR Laboratory, Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Kresten Lindorff-Larsen
- Structural Biology and NMR Laboratory, Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Massimiliano Bonomi
- Institut Pasteur, Université Paris Cité, CNRS UMR 3528, Computational Structural Biology Unit, Paris, France
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4
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Dong Y, Wang J, Grewer C. Transient kinetics reveal the mechanism of competitive inhibition of the neutral amino acid transporter ASCT2. J Biol Chem 2024; 300:107382. [PMID: 38763337 PMCID: PMC11193019 DOI: 10.1016/j.jbc.2024.107382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Revised: 04/23/2024] [Accepted: 05/10/2024] [Indexed: 05/21/2024] Open
Abstract
ASCT2 (alanine serine cysteine transporter 2), a member of the solute carrier 1 family, mediates Na+-dependent exchange of small neutral amino acids across cell membranes. ASCT2 was shown to be highly expressed in tumor cells, making it a promising target for anticancer therapies. In this study, we explored the binding mechanism of the high-affinity competitive inhibitor L-cis hydroxyproline biphenyl ester (Lc-BPE) with ASCT2, using electrophysiological and rapid kinetic methods. Our investigations reveal that Lc-BPE binding requires one or two Na+ ions initially bound to the apo-transporter with high affinity, with Na1 site occupancy being more critical for inhibitor binding. In contrast to the amino acid substrate bound form, the final, third Na+ ion cannot bind, due to distortion of its binding site (Na2), thus preventing the formation of a translocation-competent complex. Based on the rapid kinetic analysis, the application of Lc-BPE generated outward transient currents, indicating that despite its net neutral nature, the binding of Lc-BPE in ASCT2 is weakly electrogenic, most likely because of asymmetric charge distribution within the amino acid moiety of the inhibitor. The preincubation with Lc-BPE also led to a decrease of the turnover rate of substrate exchange and a delay in the activation of substrate-induced anion current, indicating relatively slow Lc-BPE dissociation kinetics. Overall, our results provide new insight into the mechanism of binding of a prototypical competitive inhibitor to the ASCT transporters.
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Affiliation(s)
- Yang Dong
- Department of Chemistry, Binghamton University, Binghamton, New York, USA
| | - Jiali Wang
- Department of Chemistry, Binghamton University, Binghamton, New York, USA
| | - Christof Grewer
- Department of Chemistry, Binghamton University, Binghamton, New York, USA.
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5
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Fromer JC, Coley CW. An algorithmic framework for synthetic cost-aware decision making in molecular design. NATURE COMPUTATIONAL SCIENCE 2024; 4:440-450. [PMID: 38886590 DOI: 10.1038/s43588-024-00639-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Accepted: 05/07/2024] [Indexed: 06/20/2024]
Abstract
Small molecules exhibiting desirable property profiles are often discovered through an iterative process of designing, synthesizing and testing sets of molecules. The selection of molecules to synthesize from all possible candidates is a complex decision-making process that typically relies on expert chemist intuition. Here we propose a quantitative decision-making framework, SPARROW, that prioritizes molecules for evaluation by balancing expected information gain and synthetic cost. SPARROW integrates molecular design, property prediction and retrosynthetic planning to balance the utility of testing a molecule with the cost of batch synthesis. We demonstrate, through three case studies, that the developed algorithm captures the non-additive costs inherent to batch synthesis, leverages common reaction steps and intermediates, and scales to hundreds of molecules.
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Affiliation(s)
- Jenna C Fromer
- Department of Chemical Engineering, MIT, Cambridge, MA, USA
| | - Connor W Coley
- Department of Chemical Engineering, MIT, Cambridge, MA, USA.
- Department of Electrical Engineering and Computer Science, MIT, Cambridge, MA, USA.
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6
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Lyda BR, Leary GP, Farnsworth J, Seaver B, Silvius D, Kavanaugh MP, Esslinger CS, Natale NR. Discovery and Synthesis of Hydroxy-l-Proline Blockers of the Neutral Amino Acid Transporters SLC1A4 (ASCT1) and SLC1A5 (ASCT2). Molecules 2024; 29:2330. [PMID: 38792190 PMCID: PMC11123841 DOI: 10.3390/molecules29102330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2024] [Revised: 04/29/2024] [Accepted: 05/03/2024] [Indexed: 05/26/2024] Open
Abstract
As a conformationally restricted amino acid, hydroxy-l-proline is a versatile scaffold for the synthesis of diverse multi-functionalized pyrrolidines for probing the ligand binding sites of biological targets. With the goal to develop new inhibitors of the widely expressed amino acid transporters SLC1A4 and SLC1A5 (also known as ASCT1 and ASCT2), we synthesized and functionally screened synthetic hydroxy-l-proline derivatives using electrophysiological and radiolabeled uptake methods against amino acid transporters from the SLC1, SLC7, and SLC38 solute carrier families. We have discovered a novel class of alkoxy hydroxy-pyrrolidine carboxylic acids (AHPCs) that act as selective high-affinity inhibitors of the SLC1 family neutral amino acid transporters SLC1A4 and SLC1A5. AHPCs were computationally docked into a homology model and assessed with respect to predicted molecular orientation and functional activity. The series of hydroxyproline analogs identified here represent promising new agents to pharmacologically modulate SLC1A4 and SLC1A5 amino acid exchangers which are implicated in numerous pathophysiological processes such as cancer and neurological diseases.
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Affiliation(s)
- Brent R. Lyda
- Division of Biological Sciences, University of Montana, 32 Campus Dr., Missoula, MT 59812, USA
- Department of Biomedical and Pharmaceutical Sciences, University of Montana, 32 Campus Dr., Missoula, MT 59812, USA (B.S.); (D.S.)
| | - Gregory P. Leary
- Department of Biomedical and Pharmaceutical Sciences, University of Montana, 32 Campus Dr., Missoula, MT 59812, USA (B.S.); (D.S.)
| | - Jill Farnsworth
- Department of Biomedical and Pharmaceutical Sciences, University of Montana, 32 Campus Dr., Missoula, MT 59812, USA (B.S.); (D.S.)
| | - Benjamin Seaver
- Department of Biomedical and Pharmaceutical Sciences, University of Montana, 32 Campus Dr., Missoula, MT 59812, USA (B.S.); (D.S.)
| | - Derek Silvius
- Department of Biomedical and Pharmaceutical Sciences, University of Montana, 32 Campus Dr., Missoula, MT 59812, USA (B.S.); (D.S.)
| | - Michael P. Kavanaugh
- Department of Biomedical and Pharmaceutical Sciences, University of Montana, 32 Campus Dr., Missoula, MT 59812, USA (B.S.); (D.S.)
| | - C. Sean Esslinger
- Department of Biomedical and Pharmaceutical Sciences, University of Montana, 32 Campus Dr., Missoula, MT 59812, USA (B.S.); (D.S.)
| | - Nicholas R. Natale
- Department of Biomedical and Pharmaceutical Sciences, University of Montana, 32 Campus Dr., Missoula, MT 59812, USA (B.S.); (D.S.)
- Medicinal Chemistry Graduate Program, University of Montana, 32 Campus Dr., Missoula, MT 59812, USA
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7
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Tu G, Fu T, Zheng G, Xu B, Gou R, Luo D, Wang P, Xue W. Computational Chemistry in Structure-Based Solute Carrier Transporter Drug Design: Recent Advances and Future Perspectives. J Chem Inf Model 2024; 64:1433-1455. [PMID: 38294194 DOI: 10.1021/acs.jcim.3c01736] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
Solute carrier transporters (SLCs) are a class of important transmembrane proteins that are involved in the transportation of diverse solute ions and small molecules into cells. There are approximately 450 SLCs within the human body, and more than a quarter of them are emerging as attractive therapeutic targets for multiple complex diseases, e.g., depression, cancer, and diabetes. However, only 44 unique transporters (∼9.8% of the SLC superfamily) with 3D structures and specific binding sites have been reported. To design innovative and effective drugs targeting diverse SLCs, there are a number of obstacles that need to be overcome. However, computational chemistry, including physics-based molecular modeling and machine learning- and deep learning-based artificial intelligence (AI), provides an alternative and complementary way to the classical drug discovery approach. Here, we present a comprehensive overview on recent advances and existing challenges of the computational techniques in structure-based drug design of SLCs from three main aspects: (i) characterizing multiple conformations of the proteins during the functional process of transportation, (ii) identifying druggability sites especially the cryptic allosteric ones on the transporters for substrates and drugs binding, and (iii) discovering diverse small molecules or synthetic protein binders targeting the binding sites. This work is expected to provide guidelines for a deep understanding of the structure and function of the SLC superfamily to facilitate rational design of novel modulators of the transporters with the aid of state-of-the-art computational chemistry technologies including artificial intelligence.
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Affiliation(s)
- Gao Tu
- Chongqing Key Laboratory of Natural Product Synthesis and Drug Research, School of Pharmaceutical Sciences, Chongqing University, Chongqing 401331, China
| | - Tingting Fu
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou 310058, China
| | | | - Binbin Xu
- Chengdu Sintanovo Biotechnology Co., Ltd., Chengdu 610200, China
| | - Rongpei Gou
- Chongqing Key Laboratory of Natural Product Synthesis and Drug Research, School of Pharmaceutical Sciences, Chongqing University, Chongqing 401331, China
| | - Ding Luo
- Chongqing Key Laboratory of Natural Product Synthesis and Drug Research, School of Pharmaceutical Sciences, Chongqing University, Chongqing 401331, China
| | - Panpan Wang
- College of Chemistry and Pharmaceutical Engineering, Huanghuai University, Zhumadian 463000, China
| | - Weiwei Xue
- Chongqing Key Laboratory of Natural Product Synthesis and Drug Research, School of Pharmaceutical Sciences, Chongqing University, Chongqing 401331, China
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8
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Cebi E, Lee J, Subramani VK, Bak N, Oh C, Kim KK. Cryo-electron microscopy-based drug design. Front Mol Biosci 2024; 11:1342179. [PMID: 38501110 PMCID: PMC10945328 DOI: 10.3389/fmolb.2024.1342179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Accepted: 01/31/2024] [Indexed: 03/20/2024] Open
Abstract
Structure-based drug design (SBDD) has gained popularity owing to its ability to develop more potent drugs compared to conventional drug-discovery methods. The success of SBDD relies heavily on obtaining the three-dimensional structures of drug targets. X-ray crystallography is the primary method used for solving structures and aiding the SBDD workflow; however, it is not suitable for all targets. With the resolution revolution, enabling routine high-resolution reconstruction of structures, cryogenic electron microscopy (cryo-EM) has emerged as a promising alternative and has attracted increasing attention in SBDD. Cryo-EM offers various advantages over X-ray crystallography and can potentially replace X-ray crystallography in SBDD. To fully utilize cryo-EM in drug discovery, understanding the strengths and weaknesses of this technique and noting the key advancements in the field are crucial. This review provides an overview of the general workflow of cryo-EM in SBDD and highlights technical innovations that enable its application in drug design. Furthermore, the most recent achievements in the cryo-EM methodology for drug discovery are discussed, demonstrating the potential of this technique for advancing drug development. By understanding the capabilities and advancements of cryo-EM, researchers can leverage the benefits of designing more effective drugs. This review concludes with a discussion of the future perspectives of cryo-EM-based SBDD, emphasizing the role of this technique in driving innovations in drug discovery and development. The integration of cryo-EM into the drug design process holds great promise for accelerating the discovery of new and improved therapeutic agents to combat various diseases.
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Affiliation(s)
| | | | | | | | - Changsuk Oh
- Department of Precision Medicine, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea
| | - Kyeong Kyu Kim
- Department of Precision Medicine, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea
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9
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Xia R, Peng HF, Zhang X, Zhang HS. Comprehensive review of amino acid transporters as therapeutic targets. Int J Biol Macromol 2024; 260:129646. [PMID: 38272411 DOI: 10.1016/j.ijbiomac.2024.129646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Revised: 01/17/2024] [Accepted: 01/18/2024] [Indexed: 01/27/2024]
Abstract
The solute carrier (SLC) family, with more than 400 membrane-bound proteins, facilitates the transport of a wide array of substrates such as nutrients, ions, metabolites, and drugs across biological membranes. Amino acid transporters (AATs) are membrane transport proteins that mediate transfer of amino acids into and out of cells or cellular organelles. AATs participate in many important physiological functions including nutrient supply, metabolic transformation, energy homeostasis, redox regulation, and neurological regulation. Several AATs have been found to significantly impact the progression of human malignancies, and dysregulation of AATs results in metabolic reprogramming affecting tumor growth and progression. However, current clinical therapies that directly target AATs have not been developed. The purpose of this review is to highlight the structural and functional diversity of AATs, the molecular mechanisms in human diseases such as tumors, kidney diseases, and emerging therapeutic strategies for targeting AATs.
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Affiliation(s)
- Ran Xia
- College of Chemistry and Life Science, Beijing University of Technology, Pingleyuan 100(#), District of Chaoyang, Beijing 100124, China
| | - Hai-Feng Peng
- College of Chemistry and Life Science, Beijing University of Technology, Pingleyuan 100(#), District of Chaoyang, Beijing 100124, China
| | - Xing Zhang
- College of Chemistry and Life Science, Beijing University of Technology, Pingleyuan 100(#), District of Chaoyang, Beijing 100124, China
| | - Hong-Sheng Zhang
- College of Chemistry and Life Science, Beijing University of Technology, Pingleyuan 100(#), District of Chaoyang, Beijing 100124, China.
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10
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Cheng X, Wang Y, Gong G, Shen P, Li Z, Bian J. Design strategies and recent development of bioactive modulators for glutamine transporters. Drug Discov Today 2024; 29:103880. [PMID: 38216118 DOI: 10.1016/j.drudis.2024.103880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Revised: 12/25/2023] [Accepted: 01/08/2024] [Indexed: 01/14/2024]
Abstract
Glutamine transporters are integral to the metabolism of glutamine in both healthy tissues and cancerous cells, playing a pivotal role in maintaining amino acid balance, synthesizing biomolecules, and regulating redox equilibrium. Their critical functions in cellular metabolism make them promising targets for oncological therapies. Recent years have witnessed substantial progress in the field of glutamine transporters, marked by breakthroughs in understanding of their protein structures and the discovery of novel inhibitors, prodrugs, and radiotracers. This review provides a comprehensive update on the latest advancements in modulators targeting the glutamine transporter, with special attention given to LAT1 and ASCT2. It also discusses innovative approaches in drug design aimed at these transporters.
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Affiliation(s)
- Xinying Cheng
- School of Pharmacy, China Pharmaceutical University, Nanjing 210009, China
| | - Yezhi Wang
- School of Pharmacy, China Pharmaceutical University, Nanjing 210009, China
| | - Guangyue Gong
- School of Pharmacy, China Pharmaceutical University, Nanjing 210009, China
| | - Pei Shen
- School of Pharmacy, China Pharmaceutical University, Nanjing 210009, China
| | - Zhiyu Li
- School of Pharmacy, China Pharmaceutical University, Nanjing 210009, China.
| | - Jinlei Bian
- School of Pharmacy, China Pharmaceutical University, Nanjing 210009, China.
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11
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Jakobsen S, Nielsen CU. Exploring Amino Acid Transporters as Therapeutic Targets for Cancer: An Examination of Inhibitor Structures, Selectivity Issues, and Discovery Approaches. Pharmaceutics 2024; 16:197. [PMID: 38399253 PMCID: PMC10893028 DOI: 10.3390/pharmaceutics16020197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 01/18/2024] [Accepted: 01/28/2024] [Indexed: 02/25/2024] Open
Abstract
Amino acid transporters are abundant amongst the solute carrier family and have an important role in facilitating the transfer of amino acids across cell membranes. Because of their impact on cell nutrient distribution, they also appear to have an important role in the growth and development of cancer. Naturally, this has made amino acid transporters a novel target of interest for the development of new anticancer drugs. Many attempts have been made to develop inhibitors of amino acid transporters to slow down cancer cell growth, and some have even reached clinical trials. The purpose of this review is to help organize the available information on the efforts to discover amino acid transporter inhibitors by focusing on the amino acid transporters ASCT2 (SLC1A5), LAT1 (SLC7A5), xCT (SLC7A11), SNAT1 (SLC38A1), SNAT2 (SLC38A2), and PAT1 (SLC36A1). We discuss the function of the transporters, their implication in cancer, their known inhibitors, issues regarding selective inhibitors, and the efforts and strategies of discovering inhibitors. The goal is to encourage researchers to continue the search and development within the field of cancer treatment research targeting amino acid transporters.
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Affiliation(s)
- Sebastian Jakobsen
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, DK-5230 Odense, Denmark
| | - Carsten Uhd Nielsen
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Campusvej 55, DK-5230 Odense, Denmark
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12
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Qin L, Cheng X, Wang S, Gong G, Su H, Huang H, Chen T, Damdinjav D, Dorjsuren B, Li Z, Qiu Z, Bian J. Discovery of Novel Aminobutanoic Acid-Based ASCT2 Inhibitors for the Treatment of Non-Small-Cell Lung Cancer. J Med Chem 2024; 67:988-1007. [PMID: 38217503 DOI: 10.1021/acs.jmedchem.3c01093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2024]
Abstract
Alanine-serine-cysteine transporter 2 (ASCT2) is up-regulated in lung cancers, and inhibiting it could potentially lead to nutrient deprivation, making it a viable strategy for cancer treatment. In this study, we present a series of ASCT2 inhibitors based on aminobutanoic acids, which exhibit potent inhibitory activity. Two compounds, 20k and 25e, were identified as novel and potent ASCT2 inhibitors, with IC50 values at the micromolar level in both A549 and HEK293 cells, effectively blocking glutamine (Gln) uptake. Additionally, these compounds regulated amino acid metabolism, suppressed mTOR signaling, inhibited non-small-cell lung cancer (NSCLC) growth, and induced apoptosis. In vivo, experiments showed that 20k and 25e suppressed tumor growth in an A549 xenograft model, with tumor growth inhibition (TGI) values of 65 and 70% at 25 mg/kg, respectively, while V9302 only achieved a TGI value of 29%. Furthermore, both compounds demonstrated promising therapeutic potential in patient-derived organoids. Therefore, these ASCT2 inhibitors based on aminobutanoic acids are promising therapeutic agents for treating NSCLC by targeting cancer Gln metabolism.
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Affiliation(s)
- Lian Qin
- State Key Laboratory of Natural Medicines, Jiangsu Key Laboratory of Drug Design and Optimization, Department of Medicinal Chemistry, China Pharmaceutical University, Nanjing 211100, P. R. China
| | - Xinying Cheng
- State Key Laboratory of Natural Medicines, Jiangsu Key Laboratory of Drug Design and Optimization, Department of Medicinal Chemistry, China Pharmaceutical University, Nanjing 211100, P. R. China
| | - Shijiao Wang
- Department of Pharmacology, School of Pharmacy, China Pharmaceutical University, Nanjing 211100, P. R. China
| | - Guangyue Gong
- State Key Laboratory of Natural Medicines, Jiangsu Key Laboratory of Drug Design and Optimization, Department of Medicinal Chemistry, China Pharmaceutical University, Nanjing 211100, P. R. China
| | - Huiyan Su
- State Key Laboratory of Natural Medicines, Jiangsu Key Laboratory of Drug Design and Optimization, Department of Medicinal Chemistry, China Pharmaceutical University, Nanjing 211100, P. R. China
| | - Huidan Huang
- School of Pharmacy, Wannan Medical College, Wuhu 241002, P. R. China
| | - Tian Chen
- State Key Laboratory of Natural Medicines, Jiangsu Key Laboratory of Drug Design and Optimization, Department of Medicinal Chemistry, China Pharmaceutical University, Nanjing 211100, P. R. China
| | - Davaadagva Damdinjav
- School of Pharmacy, Mongolian National University of Medical Science, Ulaanbaatar 14210, Mongolia
| | - Buyankhishig Dorjsuren
- Department of Pharmaceutics, China Pharmaceutical University, Nanjing 210009, P. R. China
| | - Zhiyu Li
- State Key Laboratory of Natural Medicines, Jiangsu Key Laboratory of Drug Design and Optimization, Department of Medicinal Chemistry, China Pharmaceutical University, Nanjing 211100, P. R. China
| | - Zhixia Qiu
- Department of Pharmacology, School of Pharmacy, China Pharmaceutical University, Nanjing 211100, P. R. China
| | - Jinlei Bian
- State Key Laboratory of Natural Medicines, Jiangsu Key Laboratory of Drug Design and Optimization, Department of Medicinal Chemistry, China Pharmaceutical University, Nanjing 211100, P. R. China
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13
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Jakobsen S, Petersen EF, Nielsen CU. Investigations of potential non-amino acid SNAT2 inhibitors. Front Pharmacol 2024; 14:1302445. [PMID: 38239202 PMCID: PMC10794626 DOI: 10.3389/fphar.2023.1302445] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Accepted: 12/12/2023] [Indexed: 01/22/2024] Open
Abstract
The sodium-coupled neutral amino acid transporter 2 (SNAT2, SLC38A2) has been implicated in cancer for its ability to supply cancer cells with glutamine and sarcosine. A recent high-throughput screen published by Gauthier-Coles et al. identified the non-amino acid 3-(N-methyl (4-methylphenyl)sulfonamido)-N-(2-trifluoromethylbenzyl)thiophene-2-carboxamide (MMTC or 57E) as a potent and selective SNAT2 inhibitor. Here we have investigated the ability of MMTC and four other compounds selected from the screen by Gauthier-Coles et al. to decrease 3H-Gly uptake in hyperosmotically treated human prostate cancer PC-3 cells. In these cells, SNAT2 is highly upregulated when the cells are hyperosmotically stressed for 24 h and is the primary contributor to glycine uptake. The five compounds were investigated at concentrations of 1-50 µM based on their equilibrium solubility. At 37°C the equilibrium solubility in HEPES buffered HBSS at pH 7.4 was measured to be 24.9 (53B), 56.1 (54F), 13.3 (55B), and 27.5 (57B) µM, respectively. The equilibrium solubility of MMTC was below the detection limit of the HPLC-UV method, thus less than 1.8 µM. However, a kinetic solubility of approximately 2.5-10 µM could be achieved during the course of the uptake study. In contrast to the previous publication, MMTC showed no inhibition of SNAT2-mediated 3H-Gly uptake in PC-3 cells at a concentration of 1 or 5 μM, despite a published IC50 of 0.8 µM. Similarly, 53B, 55B, and 57B showed no inhibition at soluble conditions, whereas 54F showed approximately 20% inhibition at 50 µM. In our experimental setup, the investigated compounds showed limited potential as SNAT2 inhibitors.
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Affiliation(s)
| | | | - Carsten Uhd Nielsen
- Department of Physics, Chemistry and Pharmacy, University of Southern Denmark, Odense, Denmark
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14
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Weidle UH, Birzele F. Circular RNA in Non-small Cell Lung Carcinoma: Identification of Targets and New Treatment Modalities. Cancer Genomics Proteomics 2023; 20:646-668. [PMID: 38035705 PMCID: PMC10687737 DOI: 10.21873/cgp.20413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 09/19/2023] [Accepted: 09/25/2023] [Indexed: 12/02/2023] Open
Abstract
Despite availability of several treatment options for non-small cell lung cancer (NSCLC), such as surgery, chemotherapy, radiation, targeted therapy and immunotherapy, the survival rate of patients for five years is in the range of 22%. Therefore, identification of new targets and treatment modalities for this disease is an important issue. In this context, we screened the PubMed database for up-regulated circular RNAs (circRNAs) which promote growth of NSCLC in preclinical models in vitro as well as in vivo xenograft models in immuno-compromised mice. This approach led to potential targets for further validation and inhibition with small molecules or antibody-derived entities. In case of preclinical validation, the corresponding circRNAs can be inhibited with small interfering RNAs (siRNA) or short hairpin RNAs (shRNA). The identified circRNAs act by sponging microRNAs (miRs) preventing cleavage of the mRNA of the corresponding targets. We identified nine circRNAs up-regulating transmembrane receptors, five circRNAs increasing expression of secreted proteins, nine circRNAs promoting expression of components of signaling pathways, six circRNAs involved in regulation of splicing and RNA processing, six circRNAs up-regulating actin-related and RNA processing components, seven circRNAs increasing the steady-state levels of transcription factors, two circRNAs increasing high-mobility group proteins, four circRNAs increasing components of the epigenetic modification system and three circRNAs up-regulating protein components of additional systems.
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Affiliation(s)
- Ulrich H Weidle
- Roche Pharma Research and Early Development, Roche Innovation Center Munich, Penzberg, Germany;
| | - Fabian Birzele
- Roche Pharma Research and Early Development, Pharmaceutical Sciences, Roche Innovation Center Basel, Basel, Switzerland
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15
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Du D, Qin M, Shi L, Liu C, Jiang J, Liao Z, Wang H, Zhang Z, Sun L, Fan H, Liu Z, Yu H, Li H, Peng J, Yuan S, Yang M, Xiong J. RNA binding motif protein 45-mediated phosphorylation enhances protein stability of ASCT2 to promote hepatocellular carcinoma progression. Oncogene 2023; 42:3127-3141. [PMID: 37658192 DOI: 10.1038/s41388-023-02795-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2022] [Revised: 07/17/2023] [Accepted: 07/24/2023] [Indexed: 09/03/2023]
Abstract
Targeting metabolic remodeling represents a potentially promising strategy for hepatocellular carcinoma (HCC) therapy. In-depth understanding on the regulation of the glutamine transporter alanine-serine-cysteine transporter 2 (ASCT2) contributes to the development of novel promising therapeutics. As a developmentally regulated RNA binding protein, RBM45 is capable to shuttle between nucleus and cytoplasm, and directly interacts with proteins. By bioinformatics analysis, we screened out that RBM45 was elevated in the HCC patient specimens and positively correlated with poor prognosis. RBM45 promoted cell proliferation, boosted xenograft tumorigenicity and accelerated HCC progression. Using untargeted metabolomics, it was found that RBM45 interfered with glutamine metabolism. Further results demonstrated that RBM45 positively associated with ASCT2 in human and mouse specimens. Moreover, RBM45 enhanced ASCT2 protein stability by counteracting autophagy-independent lysosomal degradation. Significantly, wild-type ASCT2, instead of phospho-defective mutants, rescued siRBM45-suppressed HCC cell proliferation. Using molecular docking approaches, we found AG-221, a mutant isocitrate dehydrogenase 2 (mIDH2) inhibitor for acute myeloid leukemia therapy, pharmacologically perturbed RBM45-ASCT2 interaction, decreased ASCT2 stability and suppressed HCC progression. These findings provide evidence that RBM45 plays a crucial role in HCC progression via interacting with and counteracting the degradation of ASCT2. Our findings suggest a novel alternative structural sites for the design of ASCT2 inhibitors and the agents interfering with RBM45-ASCT2 interaction may be a potential direction for HCC drug development.
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Affiliation(s)
- Danyu Du
- Department of Pharmacology, School of Pharmacy, China Pharmaceutical University, Nanjing, 210009, China
- Institute of Pharmaceutical Sciences, China Pharmaceutical University, Nanjing, 210009, China
| | - Mengyao Qin
- Department of Pharmacology, School of Pharmacy, China Pharmaceutical University, Nanjing, 210009, China
- Institute of Pharmaceutical Sciences, China Pharmaceutical University, Nanjing, 210009, China
| | - Li Shi
- Department of Pharmacology, School of Pharmacy, China Pharmaceutical University, Nanjing, 210009, China
| | - Chan Liu
- Department of Pharmacology, School of Pharmacy, China Pharmaceutical University, Nanjing, 210009, China
- Institute of Pharmaceutical Sciences, China Pharmaceutical University, Nanjing, 210009, China
| | - Jingwei Jiang
- Shuangyun BioMed Sci & Tech Co., Ltd., Suzhou, 215000, China
| | - Zhengguang Liao
- Institute of Pharmaceutical Sciences, China Pharmaceutical University, Nanjing, 210009, China
| | - Hongxv Wang
- Institute of Pharmaceutical Sciences, China Pharmaceutical University, Nanjing, 210009, China
| | - Zhibo Zhang
- Institute of Pharmaceutical Sciences, China Pharmaceutical University, Nanjing, 210009, China
| | - Li Sun
- Institute of Pharmaceutical Sciences, China Pharmaceutical University, Nanjing, 210009, China
| | - Hui Fan
- Department of Pharmacology, School of Pharmacy, China Pharmaceutical University, Nanjing, 210009, China
| | - Zhengrui Liu
- Institute of Pharmaceutical Sciences, China Pharmaceutical University, Nanjing, 210009, China
| | - Hong Yu
- Department of Pathology, Taizhou People's Hospital Affiliated to Dalian Medical University, Taizhou, 225300, Jiangsu, China
| | - Hongyang Li
- Institute of Dermatology, Chinese Academy of Medical Science & Peking Union Medical College, Nanjing, 210042, China
| | - Jun Peng
- Institute of Pharmaceutical Sciences, China Pharmaceutical University, Nanjing, 210009, China
| | - Shengtao Yuan
- Institute of Pharmaceutical Sciences, China Pharmaceutical University, Nanjing, 210009, China.
| | - Mei Yang
- Institute of Pharmaceutical Sciences, China Pharmaceutical University, Nanjing, 210009, China.
| | - Jing Xiong
- Department of Pharmacology, School of Pharmacy, China Pharmaceutical University, Nanjing, 210009, China.
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16
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Schlessinger A, Zatorski N, Hutchinson K, Colas C. Targeting SLC transporters: small molecules as modulators and therapeutic opportunities. Trends Biochem Sci 2023; 48:801-814. [PMID: 37355450 PMCID: PMC10525040 DOI: 10.1016/j.tibs.2023.05.011] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 05/24/2023] [Accepted: 05/25/2023] [Indexed: 06/26/2023]
Abstract
Solute carrier (SLCs) transporters mediate the transport of a broad range of solutes across biological membranes. Dysregulation of SLCs has been associated with various pathologies, including metabolic and neurological disorders, as well as cancer and rare diseases. SLCs are therefore emerging as key targets for therapeutic intervention with several recently approved drugs targeting these proteins. Unlocking this large and complex group of proteins is essential to identifying unknown SLC targets and developing next-generation SLC therapeutics. Recent progress in experimental and computational techniques has significantly advanced SLC research, including drug discovery. Here, we review emerging topics in therapeutic discovery of SLCs, focusing on state-of-the-art approaches in structural, chemical, and computational biology, and discuss current challenges in transporter drug discovery.
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Affiliation(s)
- Avner Schlessinger
- Department of Pharmacological Sciences Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA.
| | - Nicole Zatorski
- Department of Pharmacological Sciences Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Keino Hutchinson
- Department of Pharmacological Sciences Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Claire Colas
- University of Vienna, Department of Pharmaceutical Chemistry, Vienna, Austria.
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17
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Faidon Brotzakis Z, Löhr T, Truong S, Hoff S, Bonomi M, Vendruscolo M. Determination of the Structure and Dynamics of the Fuzzy Coat of an Amyloid Fibril of IAPP Using Cryo-Electron Microscopy. Biochemistry 2023; 62:2407-2416. [PMID: 37477459 PMCID: PMC10433526 DOI: 10.1021/acs.biochem.3c00010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Revised: 06/03/2023] [Indexed: 07/22/2023]
Abstract
In recent years, major advances in cryo-electron microscopy (cryo-EM) have enabled the routine determination of complex biomolecular structures at atomistic resolution. An open challenge for this approach, however, concerns large systems that exhibit continuous dynamics. To address this problem, we developed the metadynamic electron microscopy metainference (MEMMI) method, which incorporates metadynamics, an enhanced conformational sampling approach, into the metainference method of integrative structural biology. MEMMI enables the simultaneous determination of the structure and dynamics of large heterogeneous systems by combining cryo-EM density maps with prior information through molecular dynamics, while at the same time modeling the different sources of error. To illustrate the method, we apply it to elucidate the dynamics of an amyloid fibril of the islet amyloid polypeptide (IAPP). The resulting conformational ensemble provides an accurate description of the structural variability of the disordered region of the amyloid fibril, known as fuzzy coat. The conformational ensemble also reveals that in nearly half of the structural core of this amyloid fibril, the side chains exhibit liquid-like dynamics despite the presence of the highly ordered network backbone of hydrogen bonds characteristic of the cross-β structure of amyloid fibrils.
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Affiliation(s)
- Z. Faidon Brotzakis
- Centre
for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, U.K.
| | - Thomas Löhr
- Centre
for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, U.K.
| | - Steven Truong
- Centre
for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, U.K.
| | - Samuel Hoff
- Department
of Structural Biology and Chemistry, Institut
Pasteur, Université Paris Cité CNRS UMR 3528, 75015 Paris, France
| | - Massimiliano Bonomi
- Department
of Structural Biology and Chemistry, Institut
Pasteur, Université Paris Cité CNRS UMR 3528, 75015 Paris, France
| | - Michele Vendruscolo
- Centre
for Misfolding Diseases, Department of Chemistry, University of Cambridge, Cambridge CB2 1EW, U.K.
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18
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Dvorak V, Superti-Furga G. Structural and functional annotation of solute carrier transporters: implication for drug discovery. Expert Opin Drug Discov 2023; 18:1099-1115. [PMID: 37563933 DOI: 10.1080/17460441.2023.2244760] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Accepted: 08/01/2023] [Indexed: 08/12/2023]
Abstract
INTRODUCTION Solute carriers (SLCs) represent the largest group of membrane transporters in the human genome. They play a central role in controlling the compartmentalization of metabolism and most of this superfamily is linked to human disease. Despite being in general considered druggable and attractive therapeutic targets, many SLCs remain poorly annotated, both functionally and structurally. AREAS COVERED The aim of this review is to provide an overview of functional and structural parameters of SLCs that play important roles in their druggability. To do this, the authors provide an overview of experimentally solved structures of human SLCs, with emphasis on structures solved in complex with chemical modulators. From the functional annotations, the authors focus on SLC localization and SLC substrate annotations. EXPERT OPINION Recent progress in the structural and functional annotations allows to refine the SLC druggability index. Particularly the increasing number of experimentally solved structures of SLCs provides insights into mode-of-action of a significant number of chemical modulators of SLCs.
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Affiliation(s)
- Vojtech Dvorak
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
| | - Giulio Superti-Furga
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria
- Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
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19
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Dong Y, Wang J, Garibsingh RA, Hutchinson K, Shi Y, Eisenberg G, Yu X, Schlessinger A, Grewer C. Conserved allosteric inhibition mechanism in SLC1 transporters. eLife 2023; 12:e83464. [PMID: 36856089 PMCID: PMC10017108 DOI: 10.7554/elife.83464] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Accepted: 02/27/2023] [Indexed: 03/02/2023] Open
Abstract
Excitatory amino acid transporter 1 (EAAT1) is a glutamate transporter belonging to the SLC1 family of solute carriers. It plays a key role in the regulation of the extracellular glutamate concentration in the mammalian brain. The structure of EAAT1 was determined in complex with UCPH-101, apotent, non-competitive inhibitor of EAAT1. Alanine serine cysteine transporter 2 (ASCT2) is a neutral amino acid transporter, which regulates pools of amino acids such as glutamine between intracellular and extracellular compartments . ASCT2 also belongs to the SLC1 family and shares 58% sequence similarity with EAAT1. However, allosteric modulation of ASCT2 via non-competitive inhibitors is unknown. Here, we explore the UCPH-101 inhibitory mechanisms of EAAT1 and ASCT2 by using rapid kinetic experiments. Our results show that UCPH-101 slows substrate translocation rather than substrate or Na+ binding, confirming a non-competitive inhibitory mechanism, but only partially inhibits wild-type ASCT2. Guided by computational modeling using ligand docking and molecular dynamics simulations, we selected two residues involved in UCPH-101/EAAT1 interaction, which were mutated in ASCT2 (F136Y, I237M, F136Y/I237M) in the corresponding positions. We show that in the F136Y/I237M double-mutant transporter, 100% of the inhibitory effect of UCPH-101 could be restored, and the apparent affinity was increased (Ki = 4.3 μM), much closer to the EAAT1 value of 0.6 μM. Finally, we identify a novel non-competitive ASCT2 inhibitor, through virtual screening and experimental testing against the allosteric site, further supporting its localization. Together, these data indicate that the mechanism of allosteric modulation is conserved between EAAT1 and ASCT2. Due to the difference in binding site residues between ASCT2 and EAAT1, these results raise the possibility that more potent, and potentially selective ASCT2 allosteric inhibitors can be designed .
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Affiliation(s)
- Yang Dong
- Department of Chemistry, Binghamton UniversityBinghamtonUnited States
| | - Jiali Wang
- Department of Chemistry, Binghamton UniversityBinghamtonUnited States
| | - Rachel-Ann Garibsingh
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount SinaiNew YorkUnited States
| | - Keino Hutchinson
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount SinaiNew YorkUnited States
| | - Yueyue Shi
- Department of Chemistry, Binghamton UniversityBinghamtonUnited States
| | - Gilad Eisenberg
- Department of Chemistry, Binghamton UniversityBinghamtonUnited States
| | - Xiaozhen Yu
- Department of Chemistry, Binghamton UniversityBinghamtonUnited States
| | - Avner Schlessinger
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount SinaiNew YorkUnited States
| | - Christof Grewer
- Department of Chemistry, Binghamton UniversityBinghamtonUnited States
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20
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Zheng S, Liu T, Li L, Liu Q, Huang C, Liang Y, Tan Y, Zhang L, Lu X. SLC1A5, unrelated to prognosis, was associated with CD8 + T-cell exclusion in the tumor microenvironment of squamous cell carcinoma. Heliyon 2023; 9:e14571. [PMID: 36950604 PMCID: PMC10025928 DOI: 10.1016/j.heliyon.2023.e14571] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2022] [Revised: 03/09/2023] [Accepted: 03/10/2023] [Indexed: 03/17/2023] Open
Abstract
SLC1A5, short for solute carrier family 1 member 5, is a neutral amino acid transporter whose expression has been reported to be upregulated in various cancers, including esophageal squamous cell carcinoma (ESCC). Despite this, little has been described regarding the immunological involvement of SLC1A5 expression in the tumor microenvironment of ESCC. Given this, we adopted in silico analyses together with a wet lab strategy to investigate the prognostic and clinicopathological meaning of SLC1A5 expression in ESCC. In silico analyses of SLC1A5 expression data available from The Cancer Genome Atlas (TCGA) database revealed that SLC1A5 expression was unrelated to the prognosis of ESCC, which holds true when extended to other types of squamous cell carcinoma (SCC), including head and neck squamous cell carcinoma (HNSC) and lung squamous cell carcinoma (LUSC). Further analyses revealed that SLC1A5 expression correlated markedly with the infiltration density of effector CD8+ T cells in ESCC, and the same was true for HNSC and LUSC when extrapolated. As experimental confirmation, multiplexed immunofluorescent staining was undertaken to verify the correlation between SLC1A5 expression and infiltration of CD8+ T cells in a tissue microarray prepared from ESCC and matched normal control tissues. Our data confirmed that SLC1A5 expression was not associated with prognosis but was associated with the exclusion of CD8+ T cells. Taken together, all the data we curated strongly support the notion that SLC1A5 expression is associated with CD8+ T-cell exclusion in the tumor microenvironment of SCC.
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Affiliation(s)
- Shutao Zheng
- State Key Laboratory of Pathogenesis, Prevention, Treatment of Central Asian High Incidence Diseases, Xinjiang Uygur Autonomous Region, Urumqi, PR China
- Clinical Medical Research Institute, First Affiliated Hospital of Xinjiang Medical University, Xinjiang Uygur Autonomous Region, Urumqi, PR China
| | - Tao Liu
- Department of Clinical Laboratory, First Affiliated Hospital of Xinjiang Medical University, Xinjiang Uygur Autonomous Region, Urumqi, PR China
| | - Lu Li
- Department of Clinical Laboratory, First Affiliated Hospital of Xinjiang Medical University, Xinjiang Uygur Autonomous Region, Urumqi, PR China
| | - Qing Liu
- State Key Laboratory of Pathogenesis, Prevention, Treatment of Central Asian High Incidence Diseases, Xinjiang Uygur Autonomous Region, Urumqi, PR China
- Clinical Medical Research Institute, First Affiliated Hospital of Xinjiang Medical University, Xinjiang Uygur Autonomous Region, Urumqi, PR China
| | - Conggai Huang
- State Key Laboratory of Pathogenesis, Prevention, Treatment of Central Asian High Incidence Diseases, Xinjiang Uygur Autonomous Region, Urumqi, PR China
- Department of Pathology, The Affiliated Hospital of Southwest Medical University, Luzhou, 646000, China
| | - Yan Liang
- Department of Pathology, Basic Medicine College, Xinjiang Medical University, Urumqi, 830017, China
| | - Yiyi Tan
- Clinical Medical Research Institute, First Affiliated Hospital of Xinjiang Medical University, Xinjiang Uygur Autonomous Region, Urumqi, PR China
| | - Li Zhang
- State Key Laboratory of Pathogenesis, Prevention, Treatment of Central Asian High Incidence Diseases, Xinjiang Uygur Autonomous Region, Urumqi, PR China
- VIP Medicine, First Affiliated Hospital of Xinjiang Medical University, Xinjiang Uygur Autonomous Region, Urumqi, PR China
| | - Xiaomei Lu
- State Key Laboratory of Pathogenesis, Prevention, Treatment of Central Asian High Incidence Diseases, Xinjiang Uygur Autonomous Region, Urumqi, PR China
- Clinical Medical Research Institute, First Affiliated Hospital of Xinjiang Medical University, Xinjiang Uygur Autonomous Region, Urumqi, PR China
- Corresponding author. State Key Laboratory of Pathogenesis, Prevention, Treatment of Central Asian High Incidence Diseases, Xinjiang Uygur Autonomous Region, Urumqi, PR China.
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21
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Bernetti M, Bussi G. Integrating experimental data with molecular simulations to investigate RNA structural dynamics. Curr Opin Struct Biol 2023; 78:102503. [PMID: 36463773 DOI: 10.1016/j.sbi.2022.102503] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Revised: 10/17/2022] [Accepted: 10/25/2022] [Indexed: 12/05/2022]
Abstract
Conformational dynamics is crucial for ribonucleic acid (RNA) function. Techniques such as nuclear magnetic resonance, cryo-electron microscopy, small- and wide-angle X-ray scattering, chemical probing, single-molecule Förster resonance energy transfer, or even thermal or mechanical denaturation experiments probe RNA dynamics at different time and space resolutions. Their combination with accurate atomistic molecular dynamics (MD) simulations paves the way for quantitative and detailed studies of RNA dynamics. First, experiments provide a quantitative validation tool for MD simulations. Second, available data can be used to refine simulated structural ensembles to match experiments. Finally, comparison with experiments allows for improving MD force fields that are transferable to new systems for which data is not available. Here we review the recent literature and provide our perspective on this field.
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Affiliation(s)
- Mattia Bernetti
- Computational and Chemical Biology, Italian Institute of Technology, 16152 Genova, Italy; Department of Pharmacy and Biotechnology, Alma Mater Studiorum - University of Bologna, 40126 Bologna, Italy
| | - Giovanni Bussi
- Scuola Internazionale Superiore di Studi Avanzati, via Bonomea 265, 34136, Trieste, Italy.
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22
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Hutchinson K, Silva DB, Bohlke J, Clausen C, Thomas AA, Bonomi M, Schlessinger A. Describing inhibitor specificity for the amino acid transporter LAT1 from metainference simulations. Biophys J 2022; 121:4476-4491. [PMID: 36369754 PMCID: PMC9748366 DOI: 10.1016/j.bpj.2022.11.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Revised: 09/09/2022] [Accepted: 10/31/2022] [Indexed: 11/13/2022] Open
Abstract
The human L-type amino acid transporter 1 (LAT1; SLC7A5) is a membrane transporter of amino acids, thyroid hormones, and drugs such as the Parkinson's disease drug levodopa (L-Dopa). LAT1 is found in the blood-brain barrier, testis, bone marrow, and placenta, and its dysregulation has been associated with various neurological diseases, such as autism and epilepsy, as well as cancer. In this study, we combine metainference molecular dynamics simulations, molecular docking, and experimental testing, to characterize LAT1-inhibitor interactions. We first conducted a series of molecular docking experiments to identify the most relevant interactions between LAT1's substrate-binding site and ligands, including both inhibitors and substrates. We then performed metainference molecular dynamics simulations using cryoelectron microscopy structures in different conformations of LAT1 with the electron density map as a spatial restraint, to explore the inherent heterogeneity in the structures. We analyzed the LAT1 substrate-binding site to map important LAT1-ligand interactions as well as newly described druggable pockets. Finally, this analysis guided the discovery of previously unknown LAT1 ligands using virtual screening and cellular uptake experiments. Our results improve our understanding of LAT1-inhibitor recognition, providing a framework for rational design of future lead compounds targeting this key drug target.
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Affiliation(s)
- Keino Hutchinson
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Dina Buitrago Silva
- Department of Bioengineering and Therapeutic Sciences University of California, San Francisco, San Francisco, California
| | - Joshua Bohlke
- Department of Chemistry, University of Nebraska at Kearney, Kearney, Nebraska
| | - Chase Clausen
- Department of Chemistry, University of Nebraska at Kearney, Kearney, Nebraska
| | - Allen A Thomas
- Department of Chemistry, University of Nebraska at Kearney, Kearney, Nebraska
| | - Massimiliano Bonomi
- Department of Structural Biology and Chemistry, Institut Pasteur, Université Paris Cité, CNRS UMR 3528, Paris, France.
| | - Avner Schlessinger
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York.
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23
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Zhao J, Lv J, Chen Y, Dong Q, Dong H. Recent progress of amino acid transporters as a novel antitumor target. OPEN CHEM 2022. [DOI: 10.1515/chem-2022-0239] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Abstract
Glutamine transporters transport different amino acids for cell growth and metabolism. In tumor cells, glutamine transporters are often highly expressed and play a crucial role in their growth. By inhibiting the amino acid transport of these transporters, the growth of cancer cells can be inhibited. In recent years, more and more attention has been paid to the study of glutamine transporter. In this article, the differences between the ASC system amino acid transporter 2 (ASCT2), L-type amino acid transporter 1 (LAT1), and the cystine–glutamate exchange (xCT) transporters research progress on the mechanism of action and corresponding small molecule inhibitors are summarized. This article introduces 62 related small molecule inhibitors of different transporters of ASCT2, LAT1, and xCT. These novel chemical structures provide ideas for the research and design of targeted inhibitors of glutamine transporters, as well as important references and clues for the design of new anti-tumor drugs.
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Affiliation(s)
- Jiye Zhao
- Department of Innovation and Entrepreneurship, School of Teacher Education, Nanjing Xiaozhuang University , No. 3601 Hongjing Avenue, Jiangning District , Nanjing 211171 , China
- Department of Biomedical Engineering, School of Engineering, China Pharmaceutical University , No. 639 Longmian Avenue, Jiangning District , Nanjing 211198 , China
| | - Jiayi Lv
- Department of Biomedical Engineering, School of Engineering, China Pharmaceutical University , No. 639 Longmian Avenue, Jiangning District , Nanjing 211198 , China
| | - Yang Chen
- Department of Biomedical Engineering, School of Engineering, China Pharmaceutical University , No. 639 Longmian Avenue, Jiangning District , Nanjing 211198 , China
| | - Qile Dong
- Department of Innovation and Entrepreneurship, School of Teacher Education, Nanjing Xiaozhuang University , No. 3601 Hongjing Avenue, Jiangning District , Nanjing 211171 , China
| | - Hao Dong
- Department of Innovation and Entrepreneurship, School of Teacher Education, Nanjing Xiaozhuang University , No. 3601 Hongjing Avenue, Jiangning District , Nanjing 211171 , China
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24
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Ndaru E, Zielewicz L, Shi Y, Hutchinson K, Garibsingh RAA, Schlessinger A, Grewer C. Alanine serine cysteine transporter (ASCT) substrate binding site properties probed with hydroxyhomoserine esters. J PHYS ORG CHEM 2022; 35:e4347. [PMID: 36568026 PMCID: PMC9786560 DOI: 10.1002/poc.4347] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 03/18/2022] [Indexed: 02/06/2023]
Abstract
The glutamine transporter ASCT2 is highly overexpressed in cancer cells. Block of glutamine uptake by ASCT2 is a potential strategy to inhibit growth of cancer cells. However, pharmacology of the ASCT2 binding site is not well established. In this work, we report the computational docking to the binding site, and the synthesis of a new class of ASCT2 inhibitors based on the novel L-hydroxyhomoserine scaffold. While these compounds inhibit the ASCT2 leak anion conductance, as expected for competitive inhibitors, they did not block leak conductance in glutamate transporters (EAAT1-3 and EAAT5). They were also ineffective with respect to subtype ASCT1, which has >57% amino acid sequence similarity to ASCT2. Molecular docking studies agree very well with the experimental results and suggest specific polar interactions in the ASCT2 binding site. Our findings add to the repertoire of ASCT2 inhibitors and will aid in further studies of ASCT2 pharmacology.
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Affiliation(s)
- Elias Ndaru
- Department of Chemistry, Binghamton University, Binghamton, NY 13902
| | - Laura Zielewicz
- Department of Chemistry, Binghamton University, Binghamton, NY 13902
| | - Yueyue Shi
- Department of Chemistry, Binghamton University, Binghamton, NY 13902
| | - Keino Hutchinson
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029
| | - Rachel-Ann A Garibsingh
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029
| | - Avner Schlessinger
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029
| | - Christof Grewer
- Department of Chemistry, Binghamton University, Binghamton, NY 13902
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25
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Giacomini KM, Yee SW, Koleske ML, Zou L, Matsson P, Chen EC, Kroetz DL, Miller MA, Gozalpour E, Chu X. New and Emerging Research on Solute Carrier and ATP Binding Cassette Transporters in Drug Discovery and Development: Outlook From the International Transporter Consortium. Clin Pharmacol Ther 2022; 112:540-561. [PMID: 35488474 PMCID: PMC9398938 DOI: 10.1002/cpt.2627] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Accepted: 03/16/2022] [Indexed: 02/06/2023]
Abstract
Enabled by a plethora of new technologies, research in membrane transporters has exploded in the past decade. The goal of this state-of-the-art article is to describe recent advances in research on membrane transporters that are particularly relevant to drug discovery and development. This review covers advances in basic, translational, and clinical research that has led to an increased understanding of membrane transporters at all levels. At the basic level, we describe the available crystal structures of membrane transporters in both the solute carrier (SLC) and ATP binding cassette superfamilies, which has been enabled by the development of cryogenic electron microscopy methods. Next, we describe new research on lysosomal and mitochondrial transporters as well as recently deorphaned transporters in the SLC superfamily. The translational section includes a summary of proteomic research, which has led to a quantitative understanding of transporter levels in various cell types and tissues and new methods to modulate transporter function, such as allosteric modulators and targeted protein degraders of transporters. The section ends with a review of the effect of the gut microbiome on modulation of transporter function followed by a presentation of 3D cell cultures, which may enable in vivo predictions of transporter function. In the clinical section, we describe new genomic and pharmacogenomic research, highlighting important polymorphisms in transporters that are clinically relevant to many drugs. Finally, we describe new clinical tools, which are becoming increasingly available to enable precision medicine, with the application of tissue-derived small extracellular vesicles and real-world biomarkers.
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Affiliation(s)
- Kathleen M. Giacomini
- Department of Bioengineering and Therapeutic SciencesUniversity of California, San FranciscoSan FranciscoCaliforniaUSA
| | - Sook W. Yee
- Department of Bioengineering and Therapeutic SciencesUniversity of California, San FranciscoSan FranciscoCaliforniaUSA
| | - Megan L. Koleske
- Department of Bioengineering and Therapeutic SciencesUniversity of California, San FranciscoSan FranciscoCaliforniaUSA
| | - Ling Zou
- Pharmacokinetics and Drug MetabolismAmgen Inc.South San FranciscoCaliforniaUSA
| | - Pär Matsson
- Department of PharmacologySahlgrenska AcademyUniversity of GothenburgGothenburgSweden
| | - Eugene C. Chen
- Department of Drug Metabolism and PharmacokineticsGenentech, Inc.South San FranciscoCaliforniaUSA
| | - Deanna L. Kroetz
- Department of Bioengineering and Therapeutic SciencesUniversity of California, San FranciscoSan FranciscoCaliforniaUSA
| | - Miles A. Miller
- Center for Systems BiologyMassachusetts General HospitalBostonMassachusettsUSA
| | - Elnaz Gozalpour
- Drug Safety and MetabolismIMED Biotech UnitSafety and ADME Translational Sciences DepartmentAstraZeneca R&DCambridgeUK
| | - Xiaoyan Chu
- Department of ADME and Discovery ToxicologyMerck & Co. IncKenilworthNew JerseyUSA
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26
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Thangaratnarajah C, Rheinberger J, Paulino C. Cryo-EM studies of membrane proteins at 200 keV. Curr Opin Struct Biol 2022; 76:102440. [PMID: 36029606 DOI: 10.1016/j.sbi.2022.102440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2022] [Revised: 07/01/2022] [Accepted: 07/06/2022] [Indexed: 11/03/2022]
Abstract
Single-particle cryogenic electron-microscopy (cryo-EM) has emerged as a powerful technique for the structural characterisation of membrane proteins, especially for targets previously thought to be intractable. Taking advantage of the latest hard- and software developments, high-resolution three-dimensional (3D) reconstructions of membrane proteins by cryo-EM has become routine, with 300-kV transmission electron microscopes (TEMs) being the current standard. The use of 200-kV cryo-TEMs is gaining increasingly prominence, showing the capabilities of reaching better than 2 Å resolution for soluble proteins and better than 3 Å resolution for membrane proteins. Here, we highlight the challenges working with membrane proteins and the impact of cryo-EM, and review the technical and practical benefits, achievements and limitations of imaging at lower electron acceleration voltages.
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Affiliation(s)
- Chancievan Thangaratnarajah
- University of Groningen, Faculty of Science and Engineering, Groningen Biomolecular Sciences and Biotechnology, Electron Microscopy and Membrane Enzymology Group, Nijenborgh 4, 9747 AG, Groningen, Netherlands.
| | - Jan Rheinberger
- University of Groningen, Faculty of Science and Engineering, Groningen Biomolecular Sciences and Biotechnology, Electron Microscopy and Membrane Enzymology Group, Nijenborgh 4, 9747 AG, Groningen, Netherlands. https://twitter.com/rheinbergerj
| | - Cristina Paulino
- University of Groningen, Faculty of Science and Engineering, Groningen Biomolecular Sciences and Biotechnology, Electron Microscopy and Membrane Enzymology Group, Nijenborgh 4, 9747 AG, Groningen, Netherlands.
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27
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Freidman NJ, Briot C, Ryan RM. Characterizing unexpected interactions of a glutamine transporter inhibitor with members of the SLC1A transporter family. J Biol Chem 2022; 298:102178. [PMID: 35752361 PMCID: PMC9293768 DOI: 10.1016/j.jbc.2022.102178] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 06/14/2022] [Accepted: 06/19/2022] [Indexed: 11/29/2022] Open
Abstract
The solute carrier 1A family comprises a group of membrane proteins that act as dual-function amino acid transporters and chloride (Cl-) channels and includes the alanine serine cysteine transporters (ASCTs) as well as the excitatory amino acid transporters. ASCT2 is regarded as a promising target for cancer therapy, as it can transport glutamine and other neutral amino acids into cells and is upregulated in a range of solid tumors. The compound L-γ-glutamyl-p-nitroanilide (GPNA) is widely used in studies probing the role of ASCT2 in cancer biology; however, the mechanism by which GPNA inhibits ASCT2 is not entirely clear. Here, we used electrophysiology and radiolabelled flux assays to demonstrate that GPNA activates the Cl- conductance of ASCT2 to the same extent as a transported substrate, whilst not undergoing the full transport cycle. This is a previously unreported phenomenon for inhibitors of the solute carrier 1A family but corroborates a body of literature suggesting that the structural requirements for transport are distinct from those for Cl- channel formation. We also show that in addition to its currently known targets, GPNA inhibits several of the excitatory amino acid transporters. Together, these findings raise questions about the true mechanisms of its anticancer effects.
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Affiliation(s)
- Natasha J Freidman
- Faculty of Medicine and Health, School of Medical Sciences, University of Sydney, Sydney, New South Wales, Australia
| | - Chelsea Briot
- Faculty of Medicine and Health, School of Medical Sciences, University of Sydney, Sydney, New South Wales, Australia
| | - Renae M Ryan
- Faculty of Medicine and Health, School of Medical Sciences, University of Sydney, Sydney, New South Wales, Australia.
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28
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Duan Z, Zhou Z, Lu F, Zhang Y, Guo X, Gui C, Zhang H. Antitumor activity of mianserin (a tetracyclic antidepressant) primarily driven by the inhibition of SLC1A5-mediated glutamine transport. Invest New Drugs 2022; 40:977-989. [PMID: 35834041 DOI: 10.1007/s10637-022-01284-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Accepted: 07/06/2022] [Indexed: 11/28/2022]
Abstract
Targeting tumor metabolic vulnerabilities such as "glutamine addiction" has become an attractive approach for the discovery of novel antitumor agents. Among various mechanisms explored, SLC1A5, a membrane transporter that plays an important role in glutamine cellular uptake, represents a viable target to interfere with tumor's ability to acquire critical nutrients during proliferation. In the present study, a stably transfected HEK293 cell line with human SLC1A5 (HEK293-SLC1A5) was established for the screening and identification of small molecule SLC1A5 inhibitors. This in vitro system, in conjunction with direct measurement of SLC1A5-mediated L-glutamine-2,3,3,4,4-D5 (substrate) uptake, was practical and efficient in ensuring the specificity of SLC1A5 inhibition. Among a group of diverse compounds tested, mianserin (a tetracyclic antidepressant) demonstrated a marked inhibition of SLC1A5-mediated glutamine uptake. Subsequent investigations using SW480 cells demonstrated that mianserin was capable of inhibiting SW480 tumor growth both in vitro and in vivo, and the in vivo antitumor efficacy was correlated to the reduction of glutamine concentrations in tumor tissues. Computational analysis revealed that hydrophobic interactions between SLC1A5 and its inhibitors could be a critical factor in drug design. Taken together, the current findings confirmed the feasibility of targeting SLC1A5-mediated glutamine uptake as a novel approach for antitumor intervention. It is anticipated that structural insights obtained based on homology modeling would lead to the discovery of more potent and specific SLC1A5 inhibitors for clinical development.
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Affiliation(s)
- Zelin Duan
- College of Pharmaceutical Sciences, Soochow University, Suzhou, 215123, China
| | - Zhiyun Zhou
- College of Pharmaceutical Sciences, Soochow University, Suzhou, 215123, China
| | - Feifei Lu
- College of Pharmaceutical Sciences, Soochow University, Suzhou, 215123, China
| | - Yawen Zhang
- College of Pharmaceutical Sciences, Soochow University, Suzhou, 215123, China
| | - Xvqin Guo
- College of Pharmaceutical Sciences, Soochow University, Suzhou, 215123, China
| | - Chunshan Gui
- College of Pharmaceutical Sciences, Soochow University, Suzhou, 215123, China
| | - Hongjian Zhang
- College of Pharmaceutical Sciences, Soochow University, Suzhou, 215123, China.
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29
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Zhang Z, Chen H, Geng Z, Yu Z, Li H, Dong Y, Zhang H, Huang Z, Jiang J, Zhao Y. Structural basis of ligand binding modes of human EAAT2. Nat Commun 2022; 13:3329. [PMID: 35680945 PMCID: PMC9184463 DOI: 10.1038/s41467-022-31031-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Accepted: 05/31/2022] [Indexed: 01/07/2023] Open
Abstract
In the central nervous system (CNS), excitatory amino acid transporters (EAATs) mediate the uptake of excitatory neurotransmitter glutamate and maintain its low concentrations in the synaptic cleft for avoiding neuronal cytotoxicity. Dysfunction of EAATs can lead to many psychiatric diseases. Here we report cryo-EM structures of human EAAT2 in an inward-facing conformation, in the presence of substrate glutamate or selective inhibitor WAY-213613. The glutamate is coordinated by extensive hydrogen bonds and further stabilized by HP2. The inhibitor WAY-213613 occupies a similar binding pocket to that of the substrate glutamate. Upon association with the WAY-213613, the HP2 undergoes a substantial conformational change, and in turn stabilizes the inhibitor binding by forming hydrophobic interactions. Electrophysiological experiments elucidate that the unique S441 plays pivotal roles in the binding of hEAAT2 with glutamate or WAY-213613, and the I464-L467-V468 cluster acts as a key structural determinant for the selective inhibition of this transporter by WAY-213613.
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Affiliation(s)
- Zhenglai Zhang
- Department of Microbiology and Biotechnology, College of Life Sciences, Northeast Agricultural University, No. 600 Changjiang Road, Xiangfang District, Harbin, 150030, China.,National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
| | - Huiwen Chen
- Department of Microbiology and Biotechnology, College of Life Sciences, Northeast Agricultural University, No. 600 Changjiang Road, Xiangfang District, Harbin, 150030, China.,National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
| | - Ze Geng
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science Center, Beijing, 100191, China.,IDG/McGovern Institute for Brain Research, Peking University, Beijing, 100871, China
| | - Zhuoya Yu
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China.,State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing, 100101, China.,College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Hang Li
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China.,College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yanli Dong
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China
| | - Hongwei Zhang
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China.,College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Zhuo Huang
- State Key Laboratory of Natural and Biomimetic Drugs, Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science Center, Beijing, 100191, China. .,IDG/McGovern Institute for Brain Research, Peking University, Beijing, 100871, China.
| | - Juquan Jiang
- Department of Microbiology and Biotechnology, College of Life Sciences, Northeast Agricultural University, No. 600 Changjiang Road, Xiangfang District, Harbin, 150030, China.
| | - Yan Zhao
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China. .,State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, 15 Datun Road, Beijing, 100101, China. .,College of Life Sciences, University of Chinese Academy of Sciences, Beijing, 100049, China.
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30
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Abstract
An artificial intelligence-based method can predict distinct conformational states of membrane transporters and receptors.
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Affiliation(s)
- Avner Schlessinger
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, United States
| | - Massimiliano Bonomi
- Department of Structural Biology and Chemistry, Institut Pasteur, Université Paris Cité, Paris, France
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31
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del Alamo D, Sala D, Mchaourab HS, Meiler J. Sampling alternative conformational states of transporters and receptors with AlphaFold2. eLife 2022; 11:75751. [PMID: 35238773 PMCID: PMC9023059 DOI: 10.7554/elife.75751] [Citation(s) in RCA: 161] [Impact Index Per Article: 80.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Accepted: 03/02/2022] [Indexed: 11/13/2022] Open
Abstract
Equilibrium fluctuations and triggered conformational changes often underlie the functional cycles of membrane proteins. For example, transporters mediate the passage of molecules across cell membranes by alternating between inward- and outward-facing states, while receptors undergo intracellular structural rearrangements that initiate signaling cascades. Although the conformational plasticity of these proteins has historically posed a challenge for traditional de novo protein structure prediction pipelines, the recent success of AlphaFold2 (AF2) in CASP14 culminated in the modeling of a transporter in multiple conformations to high accuracy. Given that AF2 was designed to predict static structures of proteins, it remains unclear if this result represents an underexplored capability to accurately predict multiple conformations and/or structural heterogeneity. Here, we present an approach to drive AF2 to sample alternative conformations of topologically diverse transporters and G-protein-coupled receptors that are absent from the AF2 training set. Whereas models of most proteins generated using the default AF2 pipeline are conformationally homogeneous and nearly identical to one another, reducing the depth of the input multiple sequence alignments by stochastic subsampling led to the generation of accurate models in multiple conformations. In our benchmark, these conformations spanned the range between two experimental structures of interest, with models at the extremes of these conformational distributions observed to be among the most accurate (average template modeling score of 0.94). These results suggest a straightforward approach to identifying native-like alternative states, while also highlighting the need for the next generation of deep learning algorithms to be designed to predict ensembles of biophysically relevant states.
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Affiliation(s)
- Diego del Alamo
- Department of Molecular Physiology and Biophysics, Vanderbilt UniversityNashvilleUnited States
- Department of Chemistry, Vanderbilt UniversityNashvilleUnited States
| | - Davide Sala
- Institute for Drug Discovery, Leipzig UniversityLeipzigGermany
| | - Hassane S Mchaourab
- Department of Molecular Physiology and Biophysics, Vanderbilt UniversityNashvilleUnited States
| | - Jens Meiler
- Department of Chemistry, Vanderbilt UniversityNashvilleUnited States
- Institute for Drug Discovery, Leipzig UniversityLeipzigGermany
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32
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High Throughput Screening of a Prescription Drug Library for Inhibitors of Organic Cation Transporter 3, OCT3. Pharm Res 2022; 39:1599-1613. [PMID: 35089508 DOI: 10.1007/s11095-022-03171-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Accepted: 01/15/2022] [Indexed: 12/31/2022]
Abstract
INTRODUCTION The organic cation transporter 3 (OCT3, SLC22A3) is ubiquitously expressed and interacts with a wide array of compounds including endogenous molecules, environmental toxins and prescription drugs. Understudied as a determinant of pharmacokinetics and pharmacodynamics, OCT3 has the potential to be a major determinant of drug absorption and disposition and to be a target for drug-drug interactions (DDIs). GOAL The goal of the current study was to identify prescription drug inhibitors of OCT3. METHODS We screened a compound library consisting of 2556 prescription drugs, bioactive molecules, and natural products using a high throughput assay in HEK-293 cells stably expressing OCT3. RESULTS We identified 210 compounds that at 20 μM inhibit 50% or more of OCT3-mediated uptake of 4-Di-1-ASP (2 μM). Of these, nine were predicted to inhibit the transporter at clinically relevant unbound plasma concentrations. A Structure-Activity Relationship (SAR) model included molecular descriptors that could discriminate between inhibitors and non-inhibitors of OCT3 and was used to identify additional OCT3 inhibitors. Proteomics of human brain microvessels (BMVs) indicated that OCT3 is the highest expressed OCT in the human blood-brain barrier (BBB). CONCLUSIONS This study represents the largest screen to identify prescription drug inhibitors of OCT3. Several are sufficiently potent to inhibit the transporter at therapeutic unbound plasma levels, potentially leading to DDIs or off-target pharmacologic effects.
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33
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Functional and Kinetic Comparison of Alanine Cysteine Serine Transporters ASCT1 and ASCT2. Biomolecules 2022; 12:biom12010113. [PMID: 35053261 PMCID: PMC8773628 DOI: 10.3390/biom12010113] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 01/05/2022] [Accepted: 01/07/2022] [Indexed: 02/01/2023] Open
Abstract
Neutral amino acid transporters ASCT1 and ASCT2 are two SLC1 (solute carrier 1) family subtypes, which are specific for neutral amino acids. The other members of the SLC1 family are acidic amino acid transporters (EAATs 1–5). While the functional similarities and differences between the EAATs have been well studied, less is known about how the subtypes ASCT1 and 2 differ in kinetics and function. Here, by performing comprehensive electrophysiological analysis, we identified similarities and differences between these subtypes, as well as novel functional properties, such as apparent substrate affinities of the inward-facing conformation (in the range of 70 μM for L-serine as the substrate). Key findings were: ASCT1 has a higher apparent affinity for Na+, as well as a larger [Na+] dependence of substrate affinity compared to ASCT2. However, the general sequential Na+/substrate binding mechanism with at least one Na+ binding first, followed by amino acid substrate, followed by at least one more Na+ ion, appears to be conserved between the two subtypes. In addition, the first Na+ binding step, presumably to the Na3 site, occurs with high apparent affinity (<1 mM) in both transporters. In addition, ASCT1 and 2 show different substrate selectivities, where ASCT1 does not respond to extracellular glutamine. Finally, in both transporters, we measured rapid, capacitive charge movements upon application and removal of amino acid, due to rearrangement of the translocation equilibrium. This charge movement decays rapidly, with a time constant of 4–5 ms and recovers with a time constant in the 15 ms range after substrate removal. This places a lower limit on the turnover rate of amino acid exchange by these two transporters of 60–80 s−1.
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34
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Dokladny K, Crane JK, Kassicieh AJ, Kaper JB, Kovbasnjuk O. Cross-Talk between Probiotic Nissle 1917 and Human Colonic Epithelium Affects the Metabolite Composition and Demonstrates Host Antibacterial Effect. Metabolites 2021; 11:841. [PMID: 34940599 PMCID: PMC8706777 DOI: 10.3390/metabo11120841] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 11/18/2021] [Accepted: 11/29/2021] [Indexed: 12/04/2022] Open
Abstract
Colonic epithelium-commensal interactions play a very important role in human health and disease development. Colonic mucus serves as an ecologic niche for a myriad of commensals and provides a physical barrier between the epithelium and luminal content, suggesting that communication between the host and microbes occurs mainly by soluble factors. However, the composition of epithelia-derived metabolites and how the commensal flora influences them is less characterized. Here, we used mucus-producing human adult stem cell-derived colonoid monolayers exposed apically to probiotic E. coli strain Nissle 1917 to characterize the host-microbial communication via small molecules. We measured the metabolites in the media from host and bacterial monocultures and from bacteria-colonoid co-cultures. We found that colonoids secrete amino acids, organic acids, nucleosides, and polyamines, apically and basolaterally. The metabolites from host-bacteria co-cultures markedly differ from those of host cells grown alone or bacteria grown alone. Nissle 1917 affects the composition of apical and basolateral metabolites. Importantly, spermine, secreted apically by colonoids, shows antibacterial properties, and inhibits the growth of several bacterial strains. Our data demonstrate the existence of a cross-talk between luminal bacteria and human intestinal epithelium via metabolites, which might affect the numbers of physiologic processes including the composition of commensal flora via bactericidal effects.
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Affiliation(s)
- Karol Dokladny
- Department of Internal Medicine, Division of Gastroenterology and Hepatology, University of New Mexico Health Sciences Center, Albuquerque, NM 87106, USA;
| | - John K. Crane
- Department of Medicine, Division of Infectious Diseases, University at Buffalo, Buffalo, NY 14206, USA;
| | - Alex J. Kassicieh
- University of New Mexico School of Medicine, Albuquerque, NM 87106, USA;
| | - James B. Kaper
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD 21201, USA;
| | - Olga Kovbasnjuk
- Department of Internal Medicine, Division of Gastroenterology and Hepatology, University of New Mexico Health Sciences Center, Albuquerque, NM 87106, USA;
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD 21201, USA;
- Department of Medicine, Division of Gastroenterology and Hepatology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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