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Marin JJG, Cives-Losada C, Macias RIR, Romero MR, Marijuan RP, Hortelano-Hernandez N, Delgado-Calvo K, Villar C, Gonzalez-Santiago JM, Monte MJ, Asensio M. Impact of liver diseases and pharmacological interactions on the transportome involved in hepatic drug disposition. Biochem Pharmacol 2024:116166. [PMID: 38527556 DOI: 10.1016/j.bcp.2024.116166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Revised: 03/14/2024] [Accepted: 03/22/2024] [Indexed: 03/27/2024]
Abstract
The liver plays a pivotal role in drug disposition owing to the expression of transporters accounting for the uptake at the sinusoidal membrane and the efflux across the basolateral and canalicular membranes of hepatocytes of many different compounds. Moreover, intracellular mechanisms of phases I and II biotransformation generate, in general, inactive compounds that are more polar and easier to eliminate into bile or refluxed back toward the blood for their elimination by the kidneys, which becomes crucial when the biliary route is hampered. The set of transporters expressed at a given time, i.e., the so-called transportome, is encoded by genes belonging to two gene superfamilies named Solute Carriers (SLC) and ATP-Binding Cassette (ABC), which account mainly, but not exclusively, for the uptake and efflux of endogenous substances and xenobiotics, which include many different drugs. Besides the existence of genetic variants, which determines a marked interindividual heterogeneity regarding liver drug disposition among patients, prevalent diseases, such as cirrhosis, non-alcoholic steatohepatitis, primary sclerosing cholangitis, primary biliary cirrhosis, viral hepatitis, hepatocellular carcinoma, cholangiocarcinoma, and several cholestatic liver diseases, can alter the transportome and hence affect the pharmacokinetics of drugs used to treat these patients. Moreover, hepatic drug transporters are involved in many drug-drug interactions (DDI) that challenge the safety of using a combination of agents handled by these proteins. Updated information on these questions has been organized in this article by superfamilies and families of members of the transportome involved in hepatic drug disposition.
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Affiliation(s)
- Jose J G Marin
- Experimental Hepatology and Drug Targeting (HEVEPHARM), University of Salamanca, IBSAL, Salamanca, Spain; Center for the Study of Liver and Gastrointestinal Diseases (CIBERehd), Carlos III National Institute of Health, Madrid, Spain.
| | - Candela Cives-Losada
- Experimental Hepatology and Drug Targeting (HEVEPHARM), University of Salamanca, IBSAL, Salamanca, Spain; Center for the Study of Liver and Gastrointestinal Diseases (CIBERehd), Carlos III National Institute of Health, Madrid, Spain
| | - Rocio I R Macias
- Experimental Hepatology and Drug Targeting (HEVEPHARM), University of Salamanca, IBSAL, Salamanca, Spain; Center for the Study of Liver and Gastrointestinal Diseases (CIBERehd), Carlos III National Institute of Health, Madrid, Spain
| | - Marta R Romero
- Experimental Hepatology and Drug Targeting (HEVEPHARM), University of Salamanca, IBSAL, Salamanca, Spain; Center for the Study of Liver and Gastrointestinal Diseases (CIBERehd), Carlos III National Institute of Health, Madrid, Spain
| | - Rebeca P Marijuan
- Experimental Hepatology and Drug Targeting (HEVEPHARM), University of Salamanca, IBSAL, Salamanca, Spain
| | | | - Kevin Delgado-Calvo
- Experimental Hepatology and Drug Targeting (HEVEPHARM), University of Salamanca, IBSAL, Salamanca, Spain
| | - Carmen Villar
- Experimental Hepatology and Drug Targeting (HEVEPHARM), University of Salamanca, IBSAL, Salamanca, Spain; Department of Gastroenterology and Hepatology, University Hospital of Salamanca, Salamanca, Spain
| | - Jesus M Gonzalez-Santiago
- Experimental Hepatology and Drug Targeting (HEVEPHARM), University of Salamanca, IBSAL, Salamanca, Spain; Center for the Study of Liver and Gastrointestinal Diseases (CIBERehd), Carlos III National Institute of Health, Madrid, Spain; Department of Gastroenterology and Hepatology, University Hospital of Salamanca, Salamanca, Spain
| | - Maria J Monte
- Experimental Hepatology and Drug Targeting (HEVEPHARM), University of Salamanca, IBSAL, Salamanca, Spain; Center for the Study of Liver and Gastrointestinal Diseases (CIBERehd), Carlos III National Institute of Health, Madrid, Spain
| | - Maitane Asensio
- Experimental Hepatology and Drug Targeting (HEVEPHARM), University of Salamanca, IBSAL, Salamanca, Spain; Center for the Study of Liver and Gastrointestinal Diseases (CIBERehd), Carlos III National Institute of Health, Madrid, Spain
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2
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Stepanova M, Aherne CM. Adenosine in Intestinal Epithelial Barrier Function. Cells 2024; 13:381. [PMID: 38474346 DOI: 10.3390/cells13050381] [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: 12/23/2023] [Revised: 02/13/2024] [Accepted: 02/18/2024] [Indexed: 03/14/2024] Open
Abstract
At the intestinal front, several lines of defense are in place to resist infection and injury, the mucus layer, gut microbiome and strong epithelial junctions, to name a few. Their collaboration creates a resilient barrier. In intestinal disorders, such as inflammatory bowel disease (IBD), barrier function is compromised, which results in rampant inflammation and tissue injury. In response to the destruction, the intestinal epithelium releases adenosine, a small but powerful nucleoside that functions as an alarm signal. Amidst the chaos of inflammation, adenosine aims to restore order. Within the scope of its effects is the ability to regulate intestinal epithelial barrier integrity. This review aims to define the contributions of adenosine to mucus production, microbiome-dependent barrier protection, tight junction dynamics, chloride secretion and acid-base balance to reinforce its importance in the intestinal epithelial barrier.
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Affiliation(s)
- Mariya Stepanova
- Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland
- School of Medicine, University College Dublin, Belfield, Dublin 4, Ireland
| | - Carol M Aherne
- Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland
- School of Medicine, University College Dublin, Belfield, Dublin 4, Ireland
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Taniguchi J, Masuda T, Iwatani Y, Yamamoto K, Sakai N, Okada Y, Watanabe M. Rigorous evaluation of genetic and epigenetic effects on clinical laboratory measurements using Japanese monozygotic twins. Clin Genet 2024; 105:159-172. [PMID: 37899590 DOI: 10.1111/cge.14443] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Revised: 09/10/2023] [Accepted: 10/09/2023] [Indexed: 10/31/2023]
Abstract
The investigation of environmental effects on clinical measurements using individual samples is challenging because their genetic and environmental factors are different. However, using monozygotic twins (MZ) makes it possible to investigate the influence of environmental factors as they have the same genetic factors within pairs because the difference in the clinical traits within the MZ mostly reflect the influence of environmental factors. We hypothesized that the within-pair differences in the traits that are strongly affected by genetic factors become larger after genetic risk score (GRS) correction. Using 278 Japanese MZ pairs, we compared the change in within-pair differences in each of the 45 normalized clinical measurements before and after GRS correction, and we also attempted to correct for the effects of genetic factors to identify Cytosine-phosphodiester-Guanine (CpG) sites in DNA sequences with epigenetic effects that are regulated by genetic factors. Five traits were classified into the high heritability group, which was strongly affected by genetic factors. CpG sites could be classified into three groups: regulated only by environmental factors, regulated by environmental factors masked by genetic factors, and regulated only by genetic factors. Our method has the potential to identify trait-related methylation sites that have not yet been discovered.
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Affiliation(s)
- Jumpei Taniguchi
- Department of Clinical Laboratory and Biomedical Sciences, Osaka University Graduate School of Medicine, Suita, Japan
| | - Tatsuo Masuda
- Department of Statistical Genetics, Osaka University Graduate School of Medicine, Suita, Japan
| | - Yoshinori Iwatani
- Department of Clinical Laboratory and Biomedical Sciences, Osaka University Graduate School of Medicine, Suita, Japan
- Center for Twin Research, Osaka University Graduate School of Medicine, Suita, Japan
| | - Kenichi Yamamoto
- Department of Statistical Genetics, Osaka University Graduate School of Medicine, Suita, Japan
- Laboratory of Statistical Immunology, Immunology Frontier Research Center (WPI-IFReC), Osaka University, Suita, Japan
- Department of Pediatrics, Osaka University Graduate School of Medicine, Suita, Japan
| | - Norio Sakai
- Center for Twin Research, Osaka University Graduate School of Medicine, Suita, Japan
- Child Healthcare and Genetic Science Laboratory, Division of Health Sciences, Osaka University Graduate School of Medicine, Suita, Japan
| | - Yukinori Okada
- Department of Statistical Genetics, Osaka University Graduate School of Medicine, Suita, Japan
- Laboratory of Statistical Immunology, Immunology Frontier Research Center (WPI-IFReC), Osaka University, Suita, Japan
- Laboratory for Systems Genetics, RIKEN Center for Integrative Medical Sciences, Kanagawa, Japan
- Department of Genome Informatics, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Mikio Watanabe
- Department of Clinical Laboratory and Biomedical Sciences, Osaka University Graduate School of Medicine, Suita, Japan
- Center for Twin Research, Osaka University Graduate School of Medicine, Suita, Japan
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Weber BL, Beaver JN, Gilman TL. Summarizing studies using constitutive genetic deficiency to investigate behavioural influences of uptake 2 monoamine transporters. Basic Clin Pharmacol Toxicol 2023; 133:439-458. [PMID: 36316031 PMCID: PMC10657738 DOI: 10.1111/bcpt.13810] [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: 08/05/2022] [Revised: 10/14/2022] [Accepted: 10/24/2022] [Indexed: 11/27/2022]
Abstract
Burgeoning literature demonstrates that monoamine transporters with high transport capacity but lower substrate affinity (i.e., uptake 2) contribute meaningfully to regulation of monoamine neurotransmitter signalling. However, studying behavioural influences of uptake 2 is hindered by an absence of selective inhibitors largely free of off-target, confounding effects. This contrasts with study of monoamine transporters with low transport capacity but high substrate affinity (i.e., uptake 1), for which there are many reasonably selective inhibitors. To circumvent this dearth of pharmacological tools for studying uptake 2, researchers have instead employed mice with constitutive genetic deficiency in three separate transporters. By studying baseline behavioural shifts, plus behavioural responses to environmental and pharmacological manipulations-the latter primarily targeting uptake 1-investigators have been creatively characterizing the behavioural, and often sex-specific, influences of uptake 2. This non-systematic mini review summarizes current uptake 2 behaviour literature, highlighting emphases on stress responsivity in organic cation transporter 2 (OCT2) work, psychostimulant responsivity in OCT3 and plasma membrane monoamine transporter (PMAT) investigations, and antidepressant responsivity in all three. Collectively, this small but growing body of work reiterates the necessity for development of selective uptake 2-inhibiting drugs, with reviewed studies suggesting that these might advance personalized treatment approaches.
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Affiliation(s)
- Brady L Weber
- Department of Psychological Sciences & Brain Health Research Institute, Kent State University, Kent, Ohio, USA
| | - Jasmin N Beaver
- Department of Psychological Sciences & Brain Health Research Institute, Kent State University, Kent, Ohio, USA
| | - T Lee Gilman
- Department of Psychological Sciences & Brain Health Research Institute, Kent State University, Kent, Ohio, USA
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Yi Y, Zhang H, Chen M, Chen B, Chen Y, Li P, Zhou H, Ma Z, Jiang H. Inhibition of multiple uptake transporters in cardiomyocytes/mitochondria alleviates doxorubicin-induced cardiotoxicity. Chem Biol Interact 2023; 382:110627. [PMID: 37453608 DOI: 10.1016/j.cbi.2023.110627] [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: 03/06/2023] [Revised: 06/30/2023] [Accepted: 07/10/2023] [Indexed: 07/18/2023]
Abstract
Doxorubicin (DOX) has been widely used to treat various tumors; however, DOX-induced cardiotoxicity limits its utilization. Since high accumulation of DOX in cardiomyocytes/mitochondria is the key reason, we aimed to clarify the mechanisms of DOX uptake and explore whether selectively inhibiting DOX uptake transporters would attenuate DOX accumulation and cardiotoxicity. Our results demonstrated that OCTN1/OCTN2/PMAT (organic cation/carnitine transporter 1/2 or plasma membrane monoamine transporter), especially OCTN2, played crucial roles in DOX uptake in cardiomyocytes, while OCTN2 and OCTN1 contributed to DOX transmembrane transport in mitochondria. Metformin (1-100 μM) concentration-dependently reduced DOX (5 μM for accumulation, 500 nM for cytotoxicity) concentration and toxicity in cardiomyocytes/mitochondria via inhibition of OCTN1-, OCTN2- and PMAT-mediated DOX uptake but did not affect its efflux. Furthermore, metformin (iv: 250 and 500 mg/kg or ig: 50, 100 and 200 mg/kg) could dose-dependently reduce DOX (8 mg/kg) accumulation in mouse myocardium and attenuated its cardiotoxicity. In addition, metformin (1-100 μM) did not impair DOX efficacy in breast cancer or leukemia cells. In conclusion, our study clarified the role of multiple transporters, especially OCTN2, in DOX uptake in cardiomyocytes/mitochondria; metformin alleviated DOX-induced cardiotoxicity without compromising its antitumor efficacy by selective inhibition of multiple transporters mediated DOX accumulation in myocardium/mitochondria.
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Affiliation(s)
- Yaodong Yi
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang, PR China
| | - Hengbin Zhang
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang, PR China
| | - Mingyang Chen
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang, PR China
| | - Binxin Chen
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang, PR China
| | - Yingchun Chen
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang, PR China
| | - Ping Li
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang, PR China
| | - Hui Zhou
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang, PR China; Jinhua Institute of Zhejiang University, PR China
| | - Zhiyuan Ma
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang, PR China; Key Laboratory of Clinical Cancer Pharmacology and Toxicology Research of Zhejiang Province, Affiliated Hangzhou First People's Hospital, Zhejiang University School of Medicine, Hangzhou, PR China.
| | - Huidi Jiang
- College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang, PR China; Jinhua Institute of Zhejiang University, PR China.
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Li M, Wu X, Guo Z, Gao R, Ni Z, Cui H, Zong M, Van Bockstaele F, Lou W. Lactiplantibacillus plantarum enables blood urate control in mice through degradation of nucleosides in gastrointestinal tract. MICROBIOME 2023; 11:153. [PMID: 37468996 PMCID: PMC10354915 DOI: 10.1186/s40168-023-01605-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Accepted: 06/19/2023] [Indexed: 07/21/2023]
Abstract
BACKGROUND Lactobacillus species in gut microbiota shows great promise in alleviation of metabolic diseases. However, little is known about the molecular mechanism of how Lactobacillus interacts with metabolites in circulation. Here, using high nucleoside intake to induce hyperuricemia in mice, we investigated the improvement in systemic urate metabolism by oral administration of L. plantarum via different host pathways. RESULTS Gene expression analysis demonstrated that L. plantarum inhibited the activity of xanthine oxidase and purine nucleoside phosphorylase in liver to suppress urate synthesis. The gut microbiota composition did not dramatically change by oral administration of L. plantarum over 14 days, indicated by no significant difference in α and β diversities. However, multi-omic network analysis revealed that increase of L. plantarum and decrease of L. johnsonii contributed to a decrease in serum urate levels. Besides, genomic analysis and recombinant protein expression showed that three ribonucleoside hydrolases, RihA-C, in L. plantarum rapidly and cooperatively catalyzed the hydrolysis of nucleosides into nucleobases. Furthermore, the absorption of nucleobase by intestinal epithelial cells was less than that of nucleoside, which resulted in a reduction of urate generation, evidenced by the phenomenon that mice fed with nucleobase diet generated less serum urate than those fed with nucleoside diet over a period of 9-day gavage. CONCLUSION Collectively, our work provides substantial evidence identifying the specific role of L. plantarum in improvement of urate circulation. We highlight the importance of the enzymes RihA-C existing in L. plantarum for the urate metabolism in hyperuricemia mice induced by a high-nucleoside diet. Although the direct connection between nucleobase transport and host urate levels has not been identified, the lack of nucleobase transporter in intestinal epithelial cells might be important to decrease its absorption and metabolization for urate production, leading to the decrease of serum urate in host. These findings provide important insights into urate metabolism regulation. Video Abstract.
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Affiliation(s)
- Mengfan Li
- Lab of Applied Biocatalysis, School of Food Science and Engineering, South China University of Technology, Guangzhou, China
- Food Structure and Function Research Group (FSF), Department of Food Technology, Safety and Health, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Xiaoling Wu
- Lab of Applied Biocatalysis, School of Food Science and Engineering, South China University of Technology, Guangzhou, China
| | - Zewang Guo
- Lab of Applied Biocatalysis, School of Food Science and Engineering, South China University of Technology, Guangzhou, China
| | - Ruichen Gao
- Lab of Applied Biocatalysis, School of Food Science and Engineering, South China University of Technology, Guangzhou, China
| | - Zifu Ni
- Lab of Applied Biocatalysis, School of Food Science and Engineering, South China University of Technology, Guangzhou, China
| | - Hualing Cui
- Lab of Applied Biocatalysis, School of Food Science and Engineering, South China University of Technology, Guangzhou, China
| | - Minhua Zong
- Lab of Applied Biocatalysis, School of Food Science and Engineering, South China University of Technology, Guangzhou, China
| | - Filip Van Bockstaele
- Food Structure and Function Research Group (FSF), Department of Food Technology, Safety and Health, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium.
| | - Wenyong Lou
- Lab of Applied Biocatalysis, School of Food Science and Engineering, South China University of Technology, Guangzhou, China.
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Cheu JWS, Chiu DKC, Kwan KKL, Yang C, Yuen VWH, Goh CC, Chui NNQ, Shen W, Law CT, Li Q, Zhang MS, Bao MHR, Wong BPY, Chan CYK, Liu CX, Sit GFW, Ooi ZY, Deng H, Tse APW, Ng IOL, Wong CCL. Hypoxia-inducible factor orchestrates adenosine metabolism to promote liver cancer development. SCIENCE ADVANCES 2023; 9:eade5111. [PMID: 37146141 PMCID: PMC10162666 DOI: 10.1126/sciadv.ade5111] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Hypoxia-induced adenosine creates an immunosuppressive tumor microenvironment (TME) and dampens the efficacy of immune checkpoint inhibitors (ICIs). We found that hypoxia-inducible factor 1 (HIF-1) orchestrates adenosine efflux through two steps in hepatocellular carcinoma (HCC). First, HIF-1 activates transcriptional repressor MXI1, which inhibits adenosine kinase (ADK), resulting in the failure of adenosine phosphorylation to adenosine monophosphate. This leads to adenosine accumulation in hypoxic cancer cells. Second, HIF-1 transcriptionally activates equilibrative nucleoside transporter 4, pumping adenosine into the interstitial space of HCC, elevating extracellular adenosine levels. Multiple in vitro assays demonstrated the immunosuppressive role of adenosine on T cells and myeloid cells. Knockout of ADK in vivo skewed intratumoral immune cells to protumorigenic and promoted tumor progression. Therapeutically, combination treatment of adenosine receptor antagonists and anti-PD-1 prolonged survival of HCC-bearing mice. We illustrated the dual role of hypoxia in establishing an adenosine-mediated immunosuppressive TME and offered a potential therapeutic approach that synergizes with ICIs in HCC.
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Affiliation(s)
- Jacinth Wing-Sum Cheu
- Department of Pathology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong
- Centre for Oncology and Immunology, Hong Kong Science Park, Hong Kong
| | - David Kung-Chun Chiu
- Department of Pathology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong
| | - Kenneth Kin-Leung Kwan
- Department of Pathology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong
- Centre for Oncology and Immunology, Hong Kong Science Park, Hong Kong
| | - Chunxue Yang
- Department of Pathology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong
| | - Vincent Wai-Hin Yuen
- Department of Pathology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong
- Centre for Oncology and Immunology, Hong Kong Science Park, Hong Kong
| | - Chi Ching Goh
- Department of Pathology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong
| | - Noreen Nog-Qin Chui
- Department of Pathology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong
| | - Wei Shen
- Department of Pathology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong
- Centre for Oncology and Immunology, Hong Kong Science Park, Hong Kong
| | - Cheuk-Ting Law
- Department of Pathology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong
| | - Qidong Li
- Department of Pathology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong
| | - Misty Shuo Zhang
- Department of Pathology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong
- Centre for Oncology and Immunology, Hong Kong Science Park, Hong Kong
| | - Macus Hao-Ran Bao
- Department of Pathology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong
- Centre for Oncology and Immunology, Hong Kong Science Park, Hong Kong
| | - Bowie Po-Yee Wong
- Department of Pathology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong
| | - Cerise Yuen-Ki Chan
- Department of Pathology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong
- Centre for Oncology and Immunology, Hong Kong Science Park, Hong Kong
| | - Cindy Xinqi Liu
- Department of Pathology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong
| | - Grace Fu-Wan Sit
- Department of Pathology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong
| | - Zher Yee Ooi
- Department of Pathology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong
| | - Haijing Deng
- Department of Pathology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong
| | - Aki Pui-Wah Tse
- Department of Pathology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong
- Centre for Oncology and Immunology, Hong Kong Science Park, Hong Kong
| | - Irene Oi-Lin Ng
- Department of Pathology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong
- State Key Laboratory of Liver Research, The University of Hong Kong, Hong Kong
| | - Carmen Chak-Lui Wong
- Department of Pathology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong
- Centre for Oncology and Immunology, Hong Kong Science Park, Hong Kong
- State Key Laboratory of Liver Research, The University of Hong Kong, Hong Kong
- Guangdong-Hong Kong Joint Laboratory for RNA Medicine, Sun Yat-Sen University, Guangzhou, China 510120
- Shenzhen Hospital, The University of Hong Kong, Shenzhen, China
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Mullen NJ, Thakur R, Shukla SK, Chaika NV, Kollala SS, Wang D, He C, Fujii Y, Sharma S, Mulder SE, Sykes DB, Singh PK. ENT1 blockade by CNX-774 overcomes resistance to DHODH inhibition in pancreatic cancer. Cancer Lett 2023; 552:215981. [PMID: 36341997 PMCID: PMC10305837 DOI: 10.1016/j.canlet.2022.215981] [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: 09/01/2022] [Revised: 10/19/2022] [Accepted: 10/20/2022] [Indexed: 11/23/2022]
Abstract
Inhibitors of dihydroorotate dehydrogenase (DHODH), a key enzyme for de novo synthesis of pyrimidine nucleotides, have failed in clinical trials for various cancers despite robust efficacy in preclinical animal models. To probe for druggable mediators of DHODH inhibitor resistance, we performed a combination screen with a small molecule library against pancreatic cancer cell lines that are highly resistant to the DHODH inhibitor brequinar (BQ). The screen revealed that CNX-774, a preclinical Bruton tyrosine kinase (BTK) inhibitor, sensitizes resistant cell lines to BQ. Mechanistic studies showed that this effect is independent of BTK and instead results from inhibition of equilibrative nucleoside transporter 1 (ENT1) by CNX-774. We show that ENT1 mediates BQ resistance by taking up extracellular uridine, which is salvaged to generate pyrimidine nucleotides in a DHODH-independent manner. In BQ-resistant cell lines, BQ monotherapy slowed proliferation and caused modest pyrimidine nucleotide depletion, whereas combination treatment with BQ and CNX-774 led to profound cell viability loss and pyrimidine starvation. We also identify N-acetylneuraminic acid accumulation as a potential marker of the therapeutic efficacy of DHODH inhibitors. In an aggressive, immunocompetent pancreatic cancer mouse model, combined targeting of DHODH and ENT1 dramatically suppressed tumor growth and prolonged mouse survival. Overall, our study defines CNX-774 as a previously uncharacterized ENT1 inhibitor and provides strong proof of concept support for dual targeting of DHODH and ENT1 in pancreatic cancer.
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Affiliation(s)
- Nicholas J Mullen
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, 68198, USA
| | - Ravi Thakur
- Department of Oncology Science, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73014, USA
| | - Surendra K Shukla
- Department of Oncology Science, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73014, USA
| | - Nina V Chaika
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, 68198, USA
| | - Sai Sundeep Kollala
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, 68198, USA
| | - Dezhen Wang
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, 68198, USA
| | - Chunbo He
- Department of Oncology Science, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73014, USA
| | - Yuki Fujii
- Department of Oncology Science, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73014, USA
| | - Shikhar Sharma
- Department of Oncology Science, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73014, USA
| | - Scott E Mulder
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, 68198, USA
| | - David B Sykes
- Center for Regenerative Medicine, Massachusetts General Hospital, Boston, MA, USA; Harvard Stem Cell Institute, Cambridge, MA, 02114, USA
| | - Pankaj K Singh
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, 68198, USA; Department of Oncology Science, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73014, USA; OU Health Stephenson Cancer Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA.
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9
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Sonobe T, Akiyama T, Pearson JT. Transporter-dependent uptake and metabolism of myocardial interstitial serotonin in the rat heart. J Physiol Sci 2022; 72:27. [DOI: 10.1186/s12576-022-00852-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Accepted: 10/13/2022] [Indexed: 11/10/2022]
Abstract
AbstractTo investigate the roles of the serotonin (5-HT) transporter (SERT) and plasma membrane monoamine transporter (PMAT) in 5-HT uptake and its metabolism in the heart, we monitored myocardial interstitial levels of 5-HT and 5-HIAA, a metabolite of 5-HT by monoamine oxidase (MAO), in anesthetized rats using a microdialysis technique. Fluoxetine (SERT inhibitor), decynium-22 (PMAT inhibitor), or their mixture was locally administered by reverse-microdialysis for 60 min. Subsequently, pargyline (MAO inhibitor) was co-administered. Fluoxetine rapidly increased dialysate 5-HT concentration, while decynium-22 gradually increased it. The mixture induced a larger increase in dialysate 5-HT concentration compared to fluoxetine or decynium-22 alone. Fluoxetine increased dialysate 5-HIAA concentration, and this increase was abolished by pargyline. Decynium-22 and the mixture did not change dialysate 5-HIAA concentration, which were not affected by pargyline. Both SERT and PMAT regulate myocardial interstitial 5-HT levels by its uptake; however, 5-HT uptake via PMAT leads to 5-HT metabolism by MAO.
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10
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Nucleoside transporters and immunosuppressive adenosine signaling in the tumor microenvironment: Potential therapeutic opportunities. Pharmacol Ther 2022; 240:108300. [PMID: 36283452 DOI: 10.1016/j.pharmthera.2022.108300] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 10/17/2022] [Accepted: 10/19/2022] [Indexed: 11/30/2022]
Abstract
Adenosine compartmentalization has a profound impact on immune cell function by regulating adenosine localization and, therefore, extracellular signaling capabilities, which suppresses immune cell function in the tumor microenvironment. Nucleoside transporters, responsible for the translocation and cellular compartmentalization of hydrophilic adenosine, represent an understudied yet crucial component of adenosine disposition in the tumor microenvironment. In this review article, we will summarize what is known regarding nucleoside transporter's function within the purinome in relation to currently devised points of intervention (i.e., ectonucleotidases, adenosine receptors) for cancer immunotherapy, alterations in nucleoside transporter expression reported in cancer, and potential avenues for targeting of nucleoside transporters for the desired modulation of adenosine compartmentalization and action. Further, we put forward that nucleoside transporters are an unexplored therapeutic opportunity, and modulation of nucleoside transport processes could attenuate the pathogenic buildup of immunosuppressive adenosine in solid tumors, particularly those enriched with nucleoside transport proteins.
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11
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Boakes JC, Harborne SPD, Ngo JTS, Pliotas C, Goldman A. Novel variants provide differential stabilisation of human equilibrative nucleoside transporter 1 states. Front Mol Biosci 2022; 9:970391. [DOI: 10.3389/fmolb.2022.970391] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Accepted: 10/27/2022] [Indexed: 11/10/2022] Open
Abstract
Human equilibrative nucleoside transporters represent a major pharmaceutical target for cardiac, cancer and viral therapies. Understanding the molecular basis for transport is crucial for the development of improved therapeutics through structure-based drug design. ENTs have been proposed to utilise an alternating access mechanism of action, similar to that of the major facilitator superfamily. However, ENTs lack functionally-essential features of that superfamily, suggesting that they may use a different transport mechanism. Understanding the molecular basis of their transport requires insight into diverse conformational states. Differences between intermediate states may be discrete and mediated by subtle gating interactions, such as salt bridges. We identified four variants of human equilibrative nucleoside transporter isoform 1 (hENT1) at the large intracellular loop (ICL6) and transmembrane helix 7 (TM7) that stabilise the apo-state (∆Tm 0.7–1.5°C). Furthermore, we showed that variants K263A (ICL6) and I282V (TM7) specifically stabilise the inhibitor-bound state of hENT1 (∆∆Tm 5.0 ± 1.7°C and 3.0 ± 1.8°C), supporting the role of ICL6 in hENT1 gating. Finally, we showed that, in comparison with wild type, variant T336A is destabilised by nitrobenzylthioinosine (∆∆Tm -4.7 ± 1.1°C) and binds it seven times worse. This residue may help determine inhibitor and substrate sensitivity. Residue K263 is not present in the solved structures, highlighting the need for further structural data that include the loop regions.
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12
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Contribution of ENT4 to adenosine uptake in AC16 human cardiomyocytes under simulated ischemic conditions and its potential role in cardioprotection. Mol Biol Rep 2022; 49:11201-11208. [DOI: 10.1007/s11033-022-07902-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Revised: 08/19/2022] [Accepted: 08/24/2022] [Indexed: 10/14/2022]
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13
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Pastor-Anglada M, Mata-Ventosa A, Pérez-Torras S. Inborn Errors of Nucleoside Transporter (NT)-Encoding Genes ( SLC28 and SLC29). Int J Mol Sci 2022; 23:8770. [PMID: 35955904 PMCID: PMC9369021 DOI: 10.3390/ijms23158770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 08/01/2022] [Accepted: 08/02/2022] [Indexed: 11/29/2022] Open
Abstract
The proper regulation of nucleotide pools is essential for all types of cellular functions and depends on de novo nucleotide biosynthesis, salvage, and degradation pathways. Despite the apparent essentiality of these processes, a significant number of rare diseases associated with mutations in genes encoding various enzymes of these pathways have been already identified, and others are likely yet to come. However, knowledge on genetic alterations impacting on nucleoside and nucleobase transporters is still limited. At this moment three gene-encoding nucleoside and nucleobase transporter proteins have been reported to be mutated in humans, SLC29A1, SLC29A3, and SLC28A1, impacting on the expression and function of ENT1, ENT3, and CNT1, respectively. ENT1 alterations determine Augustine-null blood type and cause ectopic calcification during aging. ENT3 deficiency translates into various clinical manifestations and syndromes, altogether listed in the OMIM catalog as histiocytosis-lymphoadenopathy plus syndrome (OMIM#602782). CNT1 deficiency causes uridine-cytidineuria (URCTU) (OMIM#618477), a unique type of pyrimidineuria with an as yet not well-known clinical impact. Increasing knowledge on the physiological, molecular and structural features of these transporter proteins is helping us to better understand the biological basis behind the biochemical and clinical manifestations caused by these deficiencies. Moreover, they also support the view that some metabolic compensation might occur in these disturbances, because they do not seem to significantly impact nucleotide homeostasis, but rather other biological events associated with particular subtypes of transporter proteins.
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Affiliation(s)
- Marçal Pastor-Anglada
- Departament de Bioquímica i Biomedicina Molecular, Institut de Biomedicina de la Universitat de Barcelona (IBUB), Universitat de Barcelona, 08028 Barcelona, Spain
- Institut de Recerca Sant Joan de Déu (IR SJD), Esplugues de Llobregat, 08950 Barcelona, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBER EHD), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Aida Mata-Ventosa
- Departament de Bioquímica i Biomedicina Molecular, Institut de Biomedicina de la Universitat de Barcelona (IBUB), Universitat de Barcelona, 08028 Barcelona, Spain
- Institut de Recerca Sant Joan de Déu (IR SJD), Esplugues de Llobregat, 08950 Barcelona, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBER EHD), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Sandra Pérez-Torras
- Departament de Bioquímica i Biomedicina Molecular, Institut de Biomedicina de la Universitat de Barcelona (IBUB), Universitat de Barcelona, 08028 Barcelona, Spain
- Institut de Recerca Sant Joan de Déu (IR SJD), Esplugues de Llobregat, 08950 Barcelona, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBER EHD), Instituto de Salud Carlos III, 28029 Madrid, Spain
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14
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Ruel NM, Nguyen KH, Kim CS, Andrade LPS, Hammond JR. Impact of SLC43A3/ENBT1 expression and function on 6-mercaptopurine transport and cytotoxicity in human acute lymphoblastic leukemia cells. J Pharmacol Exp Ther 2022; 382:335-345. [PMID: 35798387 DOI: 10.1124/jpet.122.001155] [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: 02/04/2022] [Accepted: 06/24/2022] [Indexed: 11/22/2022] Open
Abstract
6-Mercaptopurine (6-MP) is used extensively in the treatment of acute lymphoblastic leukemia (ALL) and inflammatory bowel diseases. Our lab determined previously, using a recombinant HEK293 cell model, that the SLC43A3-encoded equilibrative nucleobase transporter 1 (ENBT1) transports 6-MP into cells and significantly impacts the cytotoxicity of 6-MP in that model. To further investigate the clinical relevance of this finding, we now extend this work to an analysis of the impact of SLC43A3/ENBT1 expression and function on 6-MP uptake and cytotoxicity in leukemic lymphoblasts, the therapeutic target of 6-MP in ALL. A panel of ALL cell lines was assessed for SLC43A3/ENBT1 expression, ENBT1 function, and sensitivity to 6-MP. There was a significant difference in SLC43A3 expression among the cell lines that positively correlated with the rate of ENBT1-mediated 6-MP uptake. Cells with the lowest expression of SLC43A3 (SUP-B15: Vmax - 22 {plus minus} 5 pmol/µl/s) were also significantly less sensitive to 6-MP induced cytotoxicity than were the highest expressing cells (ALL-1: Vmax - 69 {plus minus} 10 pmol/µl/s). Furthermore, knockdown of ENBT1 using shRNAi in RS4;11 cells caused a significant decrease in ENBT1-mediated 6-MP uptake (Vmax: RS4;11 - 40 {plus minus} 4 pmol/µl/s; RS4;11 shRNAi - 26 {plus minus} 3 pmol/µl/s) and 6-MP cytotoxicity (EC50: RS4;11: 0.58 {plus minus} 0.05 µM; RS4;11 shRNAi: 1.44 {plus minus} 0.59 µM). This study showed that ENBT1 is a major contributor to 6-MP uptake in leukemia cell lines, and may prove to be a biomarker for the therapeutic efficacy of 6-MP in patients with ALL. Significance Statement This study shows that ENBT1 is responsible for the transport of 6-MP into leukemia cells and that its level of expression can impact the cytotoxicity of 6-MP. Further studies are warranted to investigate the therapeutic implications in patient populations.
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Affiliation(s)
| | | | - Chan S Kim
- Pharmacology, University of Alberta, Canada
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15
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Ali SS, Raj R, Kaur T, Weadick B, Nayak D, No M, Protos J, Odom H, Desai K, Persaud AK, Wang J, Govindarajan R. Solute Carrier Nucleoside Transporters in Hematopoiesis and Hematological Drug Toxicities: A Perspective. Cancers (Basel) 2022; 14:cancers14133113. [PMID: 35804885 PMCID: PMC9264962 DOI: 10.3390/cancers14133113] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Revised: 06/18/2022] [Accepted: 06/22/2022] [Indexed: 02/04/2023] Open
Abstract
Simple Summary Anticancer nucleoside analogs are promising treatments that often result in damaging toxicities and therefore ineffective treatment. Mechanisms of this are not well-researched, but cellular nucleoside transport research in mice might provide additional insight given transport’s role in mammalian hematopoiesis. Cellular nucleoside transport is a notable component of mammalian hematopoiesis due to how mutations within it relate to hematological abnormities. This review encompasses nucleoside transporters, focusing on their inherent properties, hematopoietic role, and their interplay in nucleoside drug treatment side effects. We then propose potential mechanisms to explain nucleoside transport involvement in blood disorders. Finally, we point out and advocate for future research areas that would improve therapeutic outcomes for patients taking nucleoside analog therapies. Abstract Anticancer nucleoside analogs produce adverse, and at times, dose-limiting hematological toxicities that can compromise treatment efficacy, yet the mechanisms of such toxicities are poorly understood. Recently, cellular nucleoside transport has been implicated in normal blood cell formation with studies from nucleoside transporter-deficient mice providing additional insights into the regulation of mammalian hematopoiesis. Furthermore, several idiopathic human genetic disorders have revealed nucleoside transport as an important component of mammalian hematopoiesis because mutations in individual nucleoside transporter genes are linked to various hematological abnormalities, including anemia. Here, we review recent developments in nucleoside transporters, including their transport characteristics, their role in the regulation of hematopoiesis, and their potential involvement in the occurrence of adverse hematological side effects due to nucleoside drug treatment. Furthermore, we discuss the putative mechanisms by which aberrant nucleoside transport may contribute to hematological abnormalities and identify the knowledge gaps where future research may positively impact treatment outcomes for patients undergoing various nucleoside analog therapies.
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Affiliation(s)
- Syed Saqib Ali
- Division of Pharmaceutics and Pharmacology, College of Pharmacy, The Ohio State University, Columbus, OH 43210, USA; (S.S.A.); (R.R.); (T.K.); (B.W.); (D.N.); (M.N.); (J.P.); (H.O.); (K.D.); (A.K.P.)
| | - Ruchika Raj
- Division of Pharmaceutics and Pharmacology, College of Pharmacy, The Ohio State University, Columbus, OH 43210, USA; (S.S.A.); (R.R.); (T.K.); (B.W.); (D.N.); (M.N.); (J.P.); (H.O.); (K.D.); (A.K.P.)
| | - Tejinder Kaur
- Division of Pharmaceutics and Pharmacology, College of Pharmacy, The Ohio State University, Columbus, OH 43210, USA; (S.S.A.); (R.R.); (T.K.); (B.W.); (D.N.); (M.N.); (J.P.); (H.O.); (K.D.); (A.K.P.)
| | - Brenna Weadick
- Division of Pharmaceutics and Pharmacology, College of Pharmacy, The Ohio State University, Columbus, OH 43210, USA; (S.S.A.); (R.R.); (T.K.); (B.W.); (D.N.); (M.N.); (J.P.); (H.O.); (K.D.); (A.K.P.)
| | - Debasis Nayak
- Division of Pharmaceutics and Pharmacology, College of Pharmacy, The Ohio State University, Columbus, OH 43210, USA; (S.S.A.); (R.R.); (T.K.); (B.W.); (D.N.); (M.N.); (J.P.); (H.O.); (K.D.); (A.K.P.)
| | - Minnsung No
- Division of Pharmaceutics and Pharmacology, College of Pharmacy, The Ohio State University, Columbus, OH 43210, USA; (S.S.A.); (R.R.); (T.K.); (B.W.); (D.N.); (M.N.); (J.P.); (H.O.); (K.D.); (A.K.P.)
| | - Jane Protos
- Division of Pharmaceutics and Pharmacology, College of Pharmacy, The Ohio State University, Columbus, OH 43210, USA; (S.S.A.); (R.R.); (T.K.); (B.W.); (D.N.); (M.N.); (J.P.); (H.O.); (K.D.); (A.K.P.)
| | - Hannah Odom
- Division of Pharmaceutics and Pharmacology, College of Pharmacy, The Ohio State University, Columbus, OH 43210, USA; (S.S.A.); (R.R.); (T.K.); (B.W.); (D.N.); (M.N.); (J.P.); (H.O.); (K.D.); (A.K.P.)
| | - Kajal Desai
- Division of Pharmaceutics and Pharmacology, College of Pharmacy, The Ohio State University, Columbus, OH 43210, USA; (S.S.A.); (R.R.); (T.K.); (B.W.); (D.N.); (M.N.); (J.P.); (H.O.); (K.D.); (A.K.P.)
| | - Avinash K. Persaud
- Division of Pharmaceutics and Pharmacology, College of Pharmacy, The Ohio State University, Columbus, OH 43210, USA; (S.S.A.); (R.R.); (T.K.); (B.W.); (D.N.); (M.N.); (J.P.); (H.O.); (K.D.); (A.K.P.)
| | - Joanne Wang
- Department of Pharmaceutics, College of Pharmacy, University of Washington, Seattle, WA 98195, USA;
| | - Rajgopal Govindarajan
- Division of Pharmaceutics and Pharmacology, College of Pharmacy, The Ohio State University, Columbus, OH 43210, USA; (S.S.A.); (R.R.); (T.K.); (B.W.); (D.N.); (M.N.); (J.P.); (H.O.); (K.D.); (A.K.P.)
- Translational Therapeutics, The Ohio State University Comprehensive Cancer Center, Columbus, OH 43210, USA
- Correspondence: ; Tel.: +1-614-247-8269; Fax: +1-614-292-2588
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16
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Li R, Mak WWS, Li J, Zheng C, Shiu PHT, Seto SW, Lee SMY, Leung GPH. Structure-Activity Relationship Studies of 4-((4-(2-fluorophenyl)piperazin-1-yl)methyl)-6-imino-N-(naphthalen-2-yl)-1,3,5-triazin-2-amine (FPMINT) Analogues as Inhibitors of Human Equilibrative Nucleoside Transporters. Front Pharmacol 2022; 13:837555. [PMID: 35264969 PMCID: PMC8899516 DOI: 10.3389/fphar.2022.837555] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Accepted: 01/27/2022] [Indexed: 11/13/2022] Open
Abstract
Equilibrative nucleoside transporters (ENTs) play a vital role in nucleotide synthesis, regulation of adenosine function and chemotherapy. Current inhibitors of ENTs are mostly ENT1-selective. Our previous study has demonstrated that 4-((4-(2-fluorophenyl)piperazin-1-yl)methyl)-6-imino-N-(naphthalen-2-yl)-1,3,5-triazin-2-amine (FPMINT) is a novel inhibitor of ENTs, which is more selective to ENT2 than to ENT1. The present study aimed to screen a series of FPMINT analogues and study their structure-activity relationship. Nucleoside transporter-deficient cells transfected with cloned human ENT1 and ENT2 were used as in vitro models. The results of the [3H]uridine uptake study showed that the replacement of the naphthalene moiety with the benzene moiety could abolish the inhibitory effects on ENT1 and ENT2. The addition of chloride to the meta position of this benzene moiety could restore only the inhibitory effect on ENT1 but had no effect on ENT2. However, the addition of the methyl group to the meta position or the ethyl or oxymethyl group to the para position of this benzene moiety could regain the inhibitory activity on both ENT1 and ENT2. The presence of a halogen substitute, regardless of the position, in the fluorophenyl moiety next to the piperazine ring was essential for the inhibitory effects on ENT1 and ENT2. Among the analogues tested, compound 3c was the most potent inhibitor. Compound 3c reduced V max of [3H]uridine uptake in ENT1 and ENT2 without affecting K m. The inhibitory effect of compound 3c could not be washed out. Compound 3c did not affect cell viability, protein expression and internalization of ENT1 and ENT2. Therefore, similar to FPMINT, compound 3c was an irreversible and non-competitive inhibitor. Molecular docking analysis also showed that the binding site of compound 3c in ENT1 may be different from that of other conventional inhibitors. It is expected that structural modification may further improve its potency and selectivity and lead to the development of useful pharmacological agents.
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Affiliation(s)
- Renkai Li
- Department of Pharmacology and Pharmacy, University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Winston Wing-Shum Mak
- Department of Pharmacology and Pharmacy, University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Jingjing Li
- Department of Pharmacology and Pharmacy, University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Chengwen Zheng
- Department of Pharmacology and Pharmacy, University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Polly Ho-Ting Shiu
- Department of Pharmacology and Pharmacy, University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Sai-Wang Seto
- Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Kowloon, Hong Kong SAR, China
| | - Simon Ming-Yuen Lee
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Avenida da Universidade, Taipa, China
| | - George Pak-Heng Leung
- Department of Pharmacology and Pharmacy, University of Hong Kong, Pokfulam, Hong Kong SAR, China
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17
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Shi SL, Fukuda H, Chujo T, Kouwaki T, Oshiumi H, Tomizawa K, Wei FY. Export of RNA-derived modified nucleosides by equilibrative nucleoside transporters defines the magnitude of autophagy response and Zika virus replication. RNA Biol 2021; 18:478-495. [PMID: 34382915 PMCID: PMC8677048 DOI: 10.1080/15476286.2021.1960689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 07/14/2021] [Accepted: 07/23/2021] [Indexed: 11/25/2022] Open
Abstract
RNA contains a wide variety of posttranscriptional modifications covalently attached to its base or sugar group. These modified nucleosides are liberated from RNA molecules as the consequence of RNA catabolism and released into extracellular space, but the molecular mechanism of extracellular transport and its pathophysiological implications have been unclear. In the present study, we discovered that RNA-derived modified nucleosides are exported to extracellular space through equilibrative nucleoside transporters 1 and 2 (ENT1 and ENT2), with ENT1 showing higher preference for modified nucleosides than ENT2. Pharmacological inhibition or genetic deletion of ENT1 and ENT2 significantly attenuated export of modified nucleosides thereby resulting in their accumulation in cytosol. Using mutagenesis strategy, we identified an amino acid residue in ENT1 that is involved in the discrimination of unmodified and modified nucleosides. In ENTs-deficient cells, the elevated levels of intracellular modified nucleosides were closely associated with an induction of autophagy response as evidenced by increased LC3-II level. Importantly, we performed a screening of modified nucleosides capable of inducing autophagy and found that 1-methylguanosine (m1G) was sufficient to induce LC3-II levels. Pathophysiologically, defective export of modified nucleosides drastically induced Zika virus replication in an autophagy-dependent manner. In addition, we also found that pharmacological inhibition of ENTs by dilazep significantly induced Zika virus replication. Collectively, our findings highlight RNA-derived modified nucleosides as important signaling modulators that activate autophagy response and indicate that defective export of these modified nucleoside can have profound consequences for pathophysiology.
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Affiliation(s)
- Sheng-Lan Shi
- Department of Molecular Physiology, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Hiroyuki Fukuda
- Department of Molecular Physiology, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Takeshi Chujo
- Department of Molecular Physiology, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Takahisa Kouwaki
- Department of Immunology, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Hiroyuki Oshiumi
- Department of Immunology, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Kazuhito Tomizawa
- Department of Molecular Physiology, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
| | - Fan-Yan Wei
- Department of Molecular Physiology, Faculty of Life Sciences, Kumamoto University, Kumamoto, Japan
- Department of Modomics Biology and Medicine, Institute of Development, Aging and Cancer, Tohoku University, Miyagi, Japan
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18
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Emerging roles of dysregulated adenosine homeostasis in brain disorders with a specific focus on neurodegenerative diseases. J Biomed Sci 2021; 28:70. [PMID: 34635103 PMCID: PMC8507231 DOI: 10.1186/s12929-021-00766-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 10/04/2021] [Indexed: 02/07/2023] Open
Abstract
In modern societies, with an increase in the older population, age-related neurodegenerative diseases have progressively become greater socioeconomic burdens. To date, despite the tremendous effort devoted to understanding neurodegenerative diseases in recent decades, treatment to delay disease progression is largely ineffective and is in urgent demand. The development of new strategies targeting these pathological features is a timely topic. It is important to note that most degenerative diseases are associated with the accumulation of specific misfolded proteins, which is facilitated by several common features of neurodegenerative diseases (including poor energy homeostasis and mitochondrial dysfunction). Adenosine is a purine nucleoside and neuromodulator in the brain. It is also an essential component of energy production pathways, cellular metabolism, and gene regulation in brain cells. The levels of intracellular and extracellular adenosine are thus tightly controlled by a handful of proteins (including adenosine metabolic enzymes and transporters) to maintain proper adenosine homeostasis. Notably, disruption of adenosine homeostasis in the brain under various pathophysiological conditions has been documented. In the past two decades, adenosine receptors (particularly A1 and A2A adenosine receptors) have been actively investigated as important drug targets in major degenerative diseases. Unfortunately, except for an A2A antagonist (istradefylline) administered as an adjuvant treatment with levodopa for Parkinson's disease, no effective drug based on adenosine receptors has been developed for neurodegenerative diseases. In this review, we summarize the emerging findings on proteins involved in the control of adenosine homeostasis in the brain and discuss the challenges and future prospects for the development of new therapeutic treatments for neurodegenerative diseases and their associated disorders based on the understanding of adenosine homeostasis.
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Hermann R, Krajcsi P, Fluck M, Seithel-Keuth A, Bytyqi A, Galazka A, Munafo A. Review of Transporter Substrate, Inhibitor, and Inducer Characteristics of Cladribine. Clin Pharmacokinet 2021; 60:1509-1535. [PMID: 34435310 PMCID: PMC8613159 DOI: 10.1007/s40262-021-01065-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/28/2021] [Indexed: 12/23/2022]
Abstract
Cladribine is a nucleoside analog that is phosphorylated in its target cells (B- and T-lymphocytes) to its active adenosine triphosphate form (2-chlorodeoxyadenosine triphosphate). Cladribine tablets 10 mg (Mavenclad®) administered for up to 10 days per year in 2 consecutive years (3.5-mg/kg cumulative dose over 2 years) are used to treat patients with relapsing multiple sclerosis. The ATP-binding cassette, solute carrier, and nucleoside transporter substrate, inhibitor, and inducer characteristics of cladribine are reviewed in this article. Available evidence suggests that the distribution of cladribine across biological membranes is facilitated by a number of uptake and efflux transporters. Among the key ATP-binding cassette efflux transporters, only breast cancer resistance protein has been shown to be an efficient transporter of cladribine, while P-glycoprotein does not transport cladribine well. Intestinal absorption, distribution throughout the body, and intracellular uptake of cladribine appear to be exclusively mediated by equilibrative and concentrative nucleoside transporters, specifically by ENT1, ENT2, ENT4, CNT2 (low affinity), and CNT3. Renal excretion of cladribine appears to be most likely driven by breast cancer resistance protein, ENT1, and P-glycoprotein. The latter may play a role despite its poor cladribine transport efficiency in view of the renal abundance of P-glycoprotein. There is no evidence that solute carrier uptake transporters such as organic anion transporting polypeptides, organic anion transporters, and organic cation transporters are involved in the transport of cladribine. Available in vitro studies examining the inhibitor characteristics of cladribine for a total of 13 major ATP-binding cassette, solute carrier, and CNT transporters indicate that in vivo inhibition of any of these transporters by cladribine is unlikely.
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Affiliation(s)
- Robert Hermann
- Clinical Research Appliance (cr.appliance), Heinrich-Vingerhut-Weg 3, 63571, Gelnhausen, Germany.
| | | | | | | | | | | | - Alain Munafo
- Institute of Pharmacometrics, an Affiliate of Merck KGaA, Lausanne, Switzerland
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20
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Beamer E, Kuchukulla M, Boison D, Engel T. ATP and adenosine-Two players in the control of seizures and epilepsy development. Prog Neurobiol 2021; 204:102105. [PMID: 34144123 DOI: 10.1016/j.pneurobio.2021.102105] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 04/07/2021] [Accepted: 06/09/2021] [Indexed: 02/08/2023]
Abstract
Despite continuous advances in understanding the underlying pathogenesis of hyperexcitable networks and lowered seizure thresholds, the treatment of epilepsy remains a clinical challenge. Over one third of patients remain resistant to current pharmacological interventions. Moreover, even when effective in suppressing seizures, current medications are merely symptomatic without significantly altering the course of the disease. Much effort is therefore invested in identifying new treatments with novel mechanisms of action, effective in drug-refractory epilepsy patients, and with the potential to modify disease progression. Compelling evidence has demonstrated that the purines, ATP and adenosine, are key mediators of the epileptogenic process. Extracellular ATP concentrations increase dramatically under pathological conditions, where it functions as a ligand at a host of purinergic receptors. ATP, however, also forms a substrate pool for the production of adenosine, via the action of an array of extracellular ATP degrading enzymes. ATP and adenosine have assumed largely opposite roles in coupling neuronal excitability to energy homeostasis in the brain. This review integrates and critically discusses novel findings regarding how ATP and adenosine control seizures and the development of epilepsy. This includes purine receptor P1 and P2-dependent mechanisms, release and reuptake mechanisms, extracellular and intracellular purine metabolism, and emerging receptor-independent effects of purines. Finally, possible purine-based therapeutic strategies for seizure suppression and disease modification are discussed.
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Affiliation(s)
- Edward Beamer
- Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland, University of Medicine and Health Sciences, Dublin D02 YN77, Ireland; Centre for Bioscience, Manchester Metropolitan University, John Dalton Building, All Saints Campus, Manchester M15 6BH, UK
| | - Manvitha Kuchukulla
- Department of Neurosurgery, Robert Wood Johnson & New Jersey Medical Schools, Rutgers University, Piscataway, NJ 08854, USA
| | - Detlev Boison
- Department of Neurosurgery, Robert Wood Johnson & New Jersey Medical Schools, Rutgers University, Piscataway, NJ 08854, USA.
| | - Tobias Engel
- Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland, University of Medicine and Health Sciences, Dublin D02 YN77, Ireland; FutureNeuro, Science Foundation Ireland Research Centre for Chronic and Rare Neurological Diseases, Royal College of Surgeons in Ireland, University of Medicine and Health Sciences, Dublin D02 YN77, Ireland.
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Abstract
Nucleosides play central roles in all facets of life, from metabolism to cellular signaling. Because of their physiochemical properties, nucleosides are lipid bilayer impermeable and thus rely on dedicated transport systems to cross biological membranes. In humans, two unrelated protein families mediate nucleoside membrane transport: the concentrative and equilibrative nucleoside transporter families. The objective of this review is to provide a broad outlook on the current status of nucleoside transport research. We will discuss the role played by nucleoside transporters in human health and disease, with emphasis placed on recent structural advancements that have revealed detailed molecular principles of these important cellular transport systems and exploitable pharmacological features.
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Affiliation(s)
- Nicholas J. Wright
- Department of Biochemistry, Duke University Medical Center, 303 Research Drive, Durham, North Carolina, 27710, USA
| | - Seok-Yong Lee
- Department of Biochemistry, Duke University Medical Center, 303 Research Drive, Durham, North Carolina, 27710, USA
- Correspondence and requests for materials should be addressed to: S.-Y. Lee., , tel: 919-684-1005, fax: 919-684-8885
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22
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Wei R, Gust SL, Tandio D, Maheux A, Nguyen KH, Wang J, Bourque S, Plane F, Hammond JR. Deletion of murine slc29a4 modifies vascular responses to adenosine and 5-hydroxytryptamine in a sexually dimorphic manner. Physiol Rep 2021; 8:e14395. [PMID: 32170814 PMCID: PMC7070170 DOI: 10.14814/phy2.14395] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 02/18/2020] [Accepted: 02/19/2020] [Indexed: 12/15/2022] Open
Abstract
Equilibrative nucleoside transporter 4 (ENT4), encoded by SLC29A4, mediates the flux of both 5‐hydroxytryptamine (5‐HT) and adenosine across cell membranes. We hypothesized that loss of ENT4 function in mice would modify the effects of these established regulators of vascular function. Male and female wild‐type (WT) and slc29a4‐null (ENT4‐KO) mice were compared with respect to their hemodynamics and mesenteric vascular function. Male ENT4‐KO mice had a complete loss of myogenic tone in their mesenteric resistance arteries. This was accompanied by a decrease in blood flow in the superior mesenteric artery in the male ENT4‐KO mice, and a reduced responsiveness to 5‐HT. In contrast, endothelium‐dependent relaxations of mesenteric arteries from female ENT4‐KO mice were more sensitive to Ca2+‐activated K+ (KCa) channel blockade than WT mice. Female ENT4‐KO mice also demonstrated an enhanced vasodilatory response to adenosine in vivo that was not seen in males. Ketanserin (5‐HT2A inhibitor) and GR55562 (5‐HT1B/1D inhibitor) decreased 5‐HT‐induced tone, but only ketanserin inhibited the relaxant effect of 5‐HT in mesenteric arteries. 5‐HT‐evoked increases in tone were elevated in arteries from ENT4‐KO mice upon block of endothelial relaxant pathways, with arteries from female ENT4‐KO mice showing the greatest increase. Adenosine A2b receptor expression was decreased, while other adenosine transporter subtypes, as well as adenosine deaminase and adenosine kinase were increased in mesenteric arteries from male, but not female, ENT4‐KO mice. These findings indicate that deletion of slc29a4 leads to sex‐specific changes in vascular function with significant consequences for regulation of blood flow and pressure by adenosine and 5‐HT.
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Affiliation(s)
- Ran Wei
- Department of Pharmacology, University of Alberta, Edmonton, AB, Canada
| | - Stephen L Gust
- Department of Pharmacology, University of Alberta, Edmonton, AB, Canada
| | - David Tandio
- Department of Pharmacology, University of Alberta, Edmonton, AB, Canada
| | - Alexia Maheux
- Department of Pharmacology, University of Alberta, Edmonton, AB, Canada
| | - Khanh H Nguyen
- Department of Pharmacology, University of Alberta, Edmonton, AB, Canada
| | - Joanne Wang
- Department of Pharmaceutics, University of Washington, Seattle, WA, USA
| | - Stephane Bourque
- Department of Anaesthesia and Pain Medicine, University of Alberta, Edmonton, AB, Canada
| | - Frances Plane
- Department of Pharmacology, University of Alberta, Edmonton, AB, Canada
| | - James R Hammond
- Department of Pharmacology, University of Alberta, Edmonton, AB, Canada
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Abstract
Precise control of monoamine neurotransmitter levels in the central nervous system (CNS) is crucial for proper brain function. Dysfunctional monoamine signaling is associated with several neuropsychiatric and neurodegenerative disorders. The plasma membrane monoamine transporter (PMAT) is a new polyspecific organic cation transporter encoded by the SLC29A4 gene. Capable of transporting monoamine neurotransmitters with low affinity and high capacity, PMAT represents a major uptake2 transporter in the brain. Broadly expressed in multiple brain regions, PMAT can complement the high-affinity, low-capacity monoamine uptake mediated by uptake1 transporters, the serotonin, dopamine, and norepinephrine transporters (SERT, DAT, and NET, respectively). This chapter provides an overview of the molecular and functional characteristics of PMAT together with its regional and cell-type specific expression in the mammalian brain. The physiological functions of PMAT in brain monoamine homeostasis are evaluated in light of its unique transport kinetics and brain location, and in comparison with uptake1 and other uptake2 transporters (e.g., OCT3) along with corroborating experimental evidences. Lastly, the possibility of PMAT's involvement in brain pathophysiological processes, such as autism, depression, and Parkinson's disease, is discussed in the context of disease pathology and potential link to aberrant monoamine pathways.
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Gomes JI, Farinha-Ferreira M, Rei N, Gonçalves-Ribeiro J, Ribeiro JA, Sebastião AM, Vaz SH. Of adenosine and the blues: The adenosinergic system in the pathophysiology and treatment of major depressive disorder. Pharmacol Res 2020; 163:105363. [PMID: 33285234 DOI: 10.1016/j.phrs.2020.105363] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 11/30/2020] [Accepted: 12/01/2020] [Indexed: 12/28/2022]
Abstract
Major depressive disorder (MDD) is the foremost cause of global disability, being responsible for enormous personal, societal, and economical costs. Importantly, existing pharmacological treatments for MDD are partially or totally ineffective in a large segment of patients. As such, the search for novel antidepressant drug targets, anchored on a clear understanding of the etiological and pathophysiological mechanisms underpinning MDD, becomes of the utmost importance. The adenosinergic system, a highly conserved neuromodulatory system, appears as a promising novel target, given both its regulatory actions over many MDD-affected systems and processes. With this goal in mind, we herein review the evidence concerning the role of adenosine as a potential player in pathophysiology and treatment of MDD, combining data from both human and animal studies. Altogether, evidence supports the assertions that the adenosinergic system is altered in both MDD patients and animal models, and that drugs targeting this system have considerable potential as putative antidepressants. Furthermore, evidence also suggests that modifications in adenosine signaling may have a key role in the effects of several pharmacological and non-pharmacological antidepressant treatments with demonstrated efficacy, such as electroconvulsive shock, sleep deprivation, and deep brain stimulation. Lastly, it becomes clear from the available literature that there is yet much to study regarding the role of the adenosinergic system in the pathophysiology and treatment of MDD, and we suggest several avenues of research that are likely to prove fruitful.
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Affiliation(s)
- Joana I Gomes
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal; Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Miguel Farinha-Ferreira
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal; Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Nádia Rei
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal; Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Joana Gonçalves-Ribeiro
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal; Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Joaquim A Ribeiro
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal; Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Ana M Sebastião
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal; Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Sandra H Vaz
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal; Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal.
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25
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SIDT1-dependent absorption in the stomach mediates host uptake of dietary and orally administered microRNAs. Cell Res 2020; 31:247-258. [PMID: 32801357 PMCID: PMC8026584 DOI: 10.1038/s41422-020-0389-3] [Citation(s) in RCA: 61] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Accepted: 07/14/2020] [Indexed: 12/14/2022] Open
Abstract
Dietary microRNAs have been shown to be absorbed by mammals and regulate host gene expression, but the absorption mechanism remains unknown. Here, we show that SIDT1 expressed on gastric pit cells in the stomach is required for the absorption of dietary microRNAs. SIDT1-deficient mice show reduced basal levels and impaired dynamic absorption of dietary microRNAs. Notably, we identified the stomach as the primary site for dietary microRNA absorption, which is dramatically attenuated in the stomachs of SIDT1-deficient mice. Mechanistic analyses revealed that the uptake of exogenous microRNAs by gastric pit cells is SIDT1 and low-pH dependent. Furthermore, oral administration of plant-derived miR2911 retards liver fibrosis, and this protective effect was abolished in SIDT1-deficient mice. Our findings reveal a major mechanism underlying the absorption of dietary microRNAs, uncover an unexpected role of the stomach and shed light on developing small RNA therapeutics by oral delivery.
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Altaweraqi RA, Yao SYM, Smith KM, Cass CE, Young JD. HPLC reveals novel features of nucleoside and nucleobase homeostasis, nucleoside metabolism and nucleoside transport. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183247. [PMID: 32126230 DOI: 10.1016/j.bbamem.2020.183247] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Revised: 02/16/2020] [Accepted: 02/18/2020] [Indexed: 12/31/2022]
Abstract
Humans possess three members of the cation-coupled concentrative nucleoside transporter CNT (SLC 28) family, hCNT1-3: hCNT1 is selective for pyrimidine nucleosides but also transports adenosine, hCNT2 transports purine nucleosides and uridine, and hCNT3 transports both pyrimidine and purine nucleosides. hCNT1/2 transport nucleosides using the transmembrane Na+ electrochemical gradient, while hCNT3 is both Na+- and H+-coupled. By producing recombinant hCNT3 in Xenopus laevis oocytes, we have used radiochemical high performance liquid chromatography (HPLC) analysis to investigate the metabolic fate of transported [3H] or [14C] pyrimidine and purine nucleosides once inside cells. With the exception of adenosine, transported nucleosides were generally subject to minimal intracellular metabolism. We also used radiochemical HPLC analysis to study the mechanism by which adenosine functions as a low Km, low Vmax permeant of hCNT1. hCNT1-producing oocytes were pre-loaded with [3H] uridine, after which efflux of accumulated radioactivity was measured in transport medium alone, or in the presence of extracellular non-radiolabelled adenosine or uridine. hCNT1-mediated [3H]-efflux was stimulated by extracellular uridine, but inhibited by extracellular adenosine, with >95% of the radioactivity exiting cells being unmetabolized uridine, consistent with a low transmembrane mobility of the hCNT1/adenosine complex. Humans also possess four members of the equilibrative nucleoside transporter ENT (SLC 29) family, hENT1-4. Of these, hENT1 and hENT2 transport both nucleosides and nucleobases into and out of cells, but their relative contributions to nucleoside and nucleobase homeostasis and, in particular, to adenosine signaling via purinoreceptors, are not known. We therefore used HPLC to determine plasma nucleoside and nucleobase concentrations in wild-type, mENT1-, mENT2- and mENT1/mENT2-knockout (KO) mice, and to compare the findings with knockout of mCNT3. Results demonstrated that ENT1 was more important than ENT2 or CNT3 in determining plasma adenosine concentrations, indicated modest roles of ENT1 in the homeostasis of other nucleosides, and suggested that none of the transporters is a major participant in handling of nucleobases.
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Affiliation(s)
- Reema A Altaweraqi
- Membrane Protein Disease Research Group, Department of Physiology, University of Alberta, Edmonton, Alberta T6G 2H7, Canada
| | - Sylvia Y M Yao
- Membrane Protein Disease Research Group, Department of Physiology, University of Alberta, Edmonton, Alberta T6G 2H7, Canada
| | - Kyla M Smith
- Membrane Protein Disease Research Group, Department of Physiology, University of Alberta, Edmonton, Alberta T6G 2H7, Canada
| | - Carol E Cass
- Membrane Protein Disease Research Group, Department of Oncology, University of Alberta, Edmonton, Alberta T6G 2H7, Canada
| | - James D Young
- Membrane Protein Disease Research Group, Department of Physiology, University of Alberta, Edmonton, Alberta T6G 2H7, Canada.
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S-(4-Nitrobenzyl)-6-thioinosine (NBMPR) is Not a Selective Inhibitor of Equilibrative Nucleoside Transporters but Also Blocks Efflux Activity of Breast Cancer Resistance Protein. Pharm Res 2020; 37:58. [PMID: 32086630 DOI: 10.1007/s11095-020-2782-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Accepted: 02/10/2020] [Indexed: 12/14/2022]
Abstract
PURPOSE S-(4-Nitrobenzyl)-6-thioinosine (NBMPR) is routinely used at concentrations of 0.10 μM and 0.10 mM to specifically inhibit transport of nucleosides mediated by equilibrative nucleoside transporters 1 (ENT1) and 2 (ENT2), respectively. We recently showed that NBMPR (0.10 mM) might also inhibit placental active efflux of [3H]zidovudine and [3H]tenofovir disoproxil fumarate. Here we test the hypothesis that NBMPR abolishes the activity of P-glycoprotein (ABCB1) and/or breast cancer resistance protein (ABCG2). METHODS We performed accumulation assays with Hoechst 33342 (a model dual substrate of ABCB1 and ABCG2) and bi-directional transport studies with the ABCG2 substrate [3H]glyburide in transduced MDCKII cells, accumulation studies in choriocarcinoma-derived BeWo cells, and in situ dual perfusions of rat term placenta with glyburide. RESULTS NBMPR inhibited Hoechst 33342 accumulation in MDCKII-ABCG2 cells (IC50 = 53 μM) but not in MDCKII-ABCB1 and MDCKII-parental cells. NBMPR (0.10 mM) also inhibited bi-directional [3H]glyburide transport across monolayers of MDCKII-ABCG2 cells and blocked ABCG2-mediated [3H]glyburide efflux by rat term placenta in situ. CONCLUSION NBMPR at a concentration of 0.10 mM abolishes ABCG2 activity. Researchers using NBMPR to evaluate the effect of ENTs on pharmacokinetics must therefore interpret their results carefully if studying compounds that are substrates of both ENTs and ABCG2.
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Sonobe T, Akiyama T, Du C, Pearson JT. Serotonin uptake via plasma membrane monoamine transporter during myocardial ischemia-reperfusion in the rat heart in vivo. Physiol Rep 2019; 7:e14297. [PMID: 31782271 PMCID: PMC6882957 DOI: 10.14814/phy2.14297] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Serotonin (5-HT) accumulates in the heart during myocardial ischemia and induces deleterious effects on the cardiomyocytes through receptor-dependent and monoamine oxidase-dependent pathways. We aimed to clarify the involvement of extra-neuronal monoamine transporters in the clearance of 5-HT during ischemia and reperfusion in the heart. Using a microdialysis technique in the anesthetized Wistar rat heart, we monitored myocardial interstitial 5-HT and 5-hydroxyindole acetic acid (5-HIAA) concentration by means of electro-chemical detection coupled with high-performance liquid chromatography (HPLC-ECD). Effects of inhibitors of the plasma membrane monoamine transporter (PMAT) and the organic cation transporter 3 (OCT3) (decynium-22 and corticosterone) on the 5-HT and 5-HIAA concentrations during baseline, coronary occlusion, and reperfusion were investigated. Basal dialysate 5-HT concentration were increased by local administration of decynium-22, but not by corticosterone. Addition of fluoxetine, a serotonin transporter (SERT) inhibitor further increased the 5-HT concentration upon during administration of decynium-22. Decynium-22 elevated the background level of 5-HT during coronary occlusion and maintained 5-HT concentration at a high level during reperfusion. Production of 5-HIAA in the early reperfusion was significantly suppressed by decynium-22. These results indicate that PMAT and SERT independently regulate basal level of interstitial 5-HT, and PMAT plays a more important role in the clearance of 5-HT during reperfusion. These data suggest the involvement of PMAT in the monoamine oxidase-dependent deleterious pathway in the heart.
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Affiliation(s)
- Takashi Sonobe
- Department of Cardiac PhysiologyNational Cerebral and Cardiovascular Center Research InstituteSuitaOsakaJapan
| | - Tsuyoshi Akiyama
- Department of Cardiac PhysiologyNational Cerebral and Cardiovascular Center Research InstituteSuitaOsakaJapan
| | - Cheng‐Kun Du
- Department of Cardiac PhysiologyNational Cerebral and Cardiovascular Center Research InstituteSuitaOsakaJapan
| | - James T. Pearson
- Department of Cardiac PhysiologyNational Cerebral and Cardiovascular Center Research InstituteSuitaOsakaJapan
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Mutual role of ecto-5'-nucleotidase/CD73 and concentrative nucleoside transporter 3 in the intestinal uptake of dAMP. PLoS One 2019; 14:e0223892. [PMID: 31634358 PMCID: PMC6802847 DOI: 10.1371/journal.pone.0223892] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Accepted: 09/14/2019] [Indexed: 12/18/2022] Open
Abstract
2'-Deoxyadenosine 5'-monophosphate (dAMP), a deoxyribonucleotide found in DNA, affects intestinal cell growth. The molecular mechanisms underlying gastrointestinal absorption of foreign DNA ingested along with food has hardly been investigated. The aim of this study was to investigate the mechanism underlying intestinal absorption of dAMP. The uptake of [3H]dAMP by Caco-2 cells was Na+- and pH-dependent and was inhibited by various nucleosides. In contrast, nitrobenzylthioinosine (NMBPR), an equilibrative nucleoside transporter inhibitor, showed little inhibitory effects on [3H]dAMP uptake. Additionally, human concentrative nucleoside transporter (CNT) 3, transiently expressed in COS-7 cells, mediated the uptake of [3H]dAMP. A kinetic study revealed that the Km value of CNT3-mediated uptake of dAMP (59.6 μM) was close to that of 2'-deoxyadenosine (dAdo) (56.3 μM), whereas the dAMP Vmax (15.6 pmol·mg protein–1min–1) was 500-fold lesser than the dAdo Vmax (7782 pmol·mg protein–1min–1). Further, [3H]dAMP uptake was greater in COS-7 cells expressing ecto-5'-nucleotidase/CD73 with CNT3 than in those expressing CNT3 alone. These data suggest that, although dAMP is a substrate of CNT3, it is dephosphorylated to dAdo by CD73 and is efficiently absorbed as dAdo from the intestinal lumen.
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Bidirectional transport of 2-chloroadenosine by equilibrative nucleoside transporter 4 (hENT4): Evidence for allosteric kinetics at acidic pH. Sci Rep 2019; 9:13555. [PMID: 31537831 PMCID: PMC6753126 DOI: 10.1038/s41598-019-49929-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 09/02/2019] [Indexed: 01/23/2023] Open
Abstract
Adenosine has been reported to be transported by equilibrative nucleoside transporter 4 (ENT4), encoded by the SLC29A4 gene, in an acidic pH-dependent manner. This makes hENT4 of interest as a therapeutic target in acidic pathologies where adenosine is protective (e.g. vascular ischaemia). We examined the pH-sensitivity of nucleoside influx and efflux by hENT4 using a recombinant transfection model that lacks the confounding influences of other nucleoside transporters (PK15-NTD). We established that [3H]2-chloroadenosine, which is resistant to metabolism by adenosine deaminase, is a substrate for hENT4. Transport of [3H]2-chloroadenosine at a pH of 6.0 in PK15-NTD cells stably transfected with SLC29A4 was biphasic, with a low capacity (Vmax ~ 30 pmol/mg/min) high-affinity component (Km ~ 50 µM) apparent at low substrate concentrations, which shifted to a high capacity (Vmax ~ 500 pmol/mg/min) low affinity system (Km > 600 µM) displaying positive cooperativity at concentrations above 200 µM. Only the low affinity component was observed at a neutral pH of 7.5 (Km ~ 2 mM). Efflux of [3H]2-chloroadenosine from these cells was also enhanced by more than 4-fold at an acidic pH. Enhanced influx and efflux of nucleosides by hENT4 under acidic conditions supports its potential as a therapeutic target in pathologies such as ischaemia-reperfusion injury.
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Subiabre M, Villalobos-Labra R, Silva L, Fuentes G, Toledo F, Sobrevia L. Role of insulin, adenosine, and adipokine receptors in the foetoplacental vascular dysfunction in gestational diabetes mellitus. Biochim Biophys Acta Mol Basis Dis 2019; 1866:165370. [PMID: 30660686 DOI: 10.1016/j.bbadis.2018.12.021] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Revised: 12/18/2018] [Accepted: 12/21/2018] [Indexed: 12/11/2022]
Abstract
Gestational diabetes mellitus (GDM) is a disease of pregnancy associated with maternal and foetal hyperglycaemia and altered foetoplacental vascular function. Human foetoplacental microvascular and macrovascular endothelium from GDM pregnancy show increased maximal l-arginine transport capacity via the human cationic amino acid transporter 1 (hCAT-1) isoform and nitric oxide (NO) synthesis by the endothelial NO synthase (eNOS). These alterations are paralleled by lower maximal transport activity of the endogenous nucleoside adenosine via the human equilibrative nucleoside transporter 1 (hENT1) and activation of adenosine receptors. A causal relationship has been described for adenosine-activation of A2A adenosine receptors, hCAT-1, and eNOS activity (i.e. the Adenosine/l-Arginine/Nitric Oxide, ALANO, signalling pathway). Insulin restores these alterations in GDM via activation of insulin receptor A (IR-A) form in the macrovascular but IR-A and IR-B forms in the microcirculation of the human placenta. Adipokines are secreted from adipocytes influencing the foetoplacental metabolic and vascular function. Various adipokines are dysregulated in GDM, with adiponectin and leptin playing major roles. Abnormal plasma concentration of these adipokines and the activation or their receptors are involved in the pathophysiology of GDM. However, involvement of adipokines, adenosine, and insulin receptors and membrane transporters in the aetiology of this disease of pregnancy is unknown. This review focuses on the pathophysiology of insulin and adenosine receptors and l-arginine and adenosine membranes transporters giving an overview of the key adipokines leptin and adiponectin in the foetoplacental vasculature in GDM. This article is part of a Special Issue entitled: Membrane Transporters and Receptors in Pregnancy Metabolic Complications edited by Luis Sobrevia.
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Affiliation(s)
- Mario Subiabre
- Cellular and Molecular Physiology Laboratory (CMPL), Department of Obstetrics, Division of Obstetrics and Gynaecology, School of Medicine, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile.
| | - Roberto Villalobos-Labra
- Cellular and Molecular Physiology Laboratory (CMPL), Department of Obstetrics, Division of Obstetrics and Gynaecology, School of Medicine, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile
| | - Luis Silva
- Cellular and Molecular Physiology Laboratory (CMPL), Department of Obstetrics, Division of Obstetrics and Gynaecology, School of Medicine, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile; Immunoendocrinology, Division of Medical Biology, Department of Pathology and Medical Biology, University of Groningen, University Medical Centre Groningen (UMCG), Groningen 9700 RB, the Netherlands
| | - Gonzalo Fuentes
- Cellular and Molecular Physiology Laboratory (CMPL), Department of Obstetrics, Division of Obstetrics and Gynaecology, School of Medicine, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile; Cell Physiology Laboratory, Biomedical Department, Faculty of Health Sciences, Universidad de Antofagasta, Antofagasta 1270300, Chile
| | - Fernando Toledo
- Cellular and Molecular Physiology Laboratory (CMPL), Department of Obstetrics, Division of Obstetrics and Gynaecology, School of Medicine, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile; Department of Basic Sciences, Faculty of Sciences, Universidad del Bío Bío, Chillán 3780000, Chile
| | - Luis Sobrevia
- Cellular and Molecular Physiology Laboratory (CMPL), Department of Obstetrics, Division of Obstetrics and Gynaecology, School of Medicine, Faculty of Medicine, Pontificia Universidad Católica de Chile, Santiago 8330024, Chile; Department of Physiology, Faculty of Pharmacy, Universidad de Sevilla, Seville E-41012, Spain; University of Queensland Centre for Clinical Research (UQCCR), Faculty of Medicine and Biomedical Sciences, University of Queensland, Herston 4029, Queensland, Australia.
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Xue Y, Ma C, Hanna I, Pan G. Intestinal Transporter-Associated Drug Absorption and Toxicity. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1141:361-405. [DOI: 10.1007/978-981-13-7647-4_8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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Role of cysteine 416 in N-ethylmaleimide sensitivity of human equilibrative nucleoside transporter 1 (hENT1). Biochem J 2018; 475:3293-3309. [PMID: 30254099 DOI: 10.1042/bcj20180543] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Revised: 09/19/2018] [Accepted: 09/25/2018] [Indexed: 12/23/2022]
Abstract
Human equilibrative nucleoside transporter 1 (hENT1), the first identified member of the ENT family of integral membrane proteins, is the primary mechanism for cellular uptake of physiologic nucleosides and many antineoplastic and antiviral nucleoside drugs. hENT1, which is potently inhibited by nitrobenzylthioinosine (NBMPR), possesses 11 transmembrane helical domains with an intracellular N-terminus and an extracellular C-terminus. As a protein with 10 endogenous cysteine residues, it is sensitive to inhibition by the membrane permeable sulfhydryl-reactive reagent N-ethylmaleimide (NEM) but is unaffected by the membrane impermeable sulfhydryl-reactive reagent p-chloromercuriphenyl sulfonate. To identify the residue(s) involved in NEM inhibition, we created a cysteine-less version of hENT1 (hENT1C-), with all 10 endogenous cysteine residues mutated to serine, and showed that it displays wild-type uridine transport and NBMPR-binding characteristics when produced in the Xenopus oocyte heterologous expression system, indicating that endogenous cysteine residues are not essential for hENT1 function. We then tested NEM sensitivity of recombinant wild-type hENT1, hENT1 mutants C1S to C10S (single cysteine residues replaced by serine), hENT1C- (all cysteine residues replaced by serine), and hENT1C- mutants S1C to S10C (single serine residues converted back to cysteine). Mutants C9S (C416S/hENT1) and S9C (S416C/hENT1C-) were insensitive and sensitive, respectively, to inhibition by NEM, identifying Cys416 as the endofacial cysteine residue in hENT1 responsible for NEM inhibition. Kinetic experiments suggested that NEM modification of Cys416, which is located at the inner extremity of TM10, results in the inhibition of hENT1 uridine transport and NBMPR binding by constraining the protein in its inward-facing conformation.
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Aherne CM, Collins CB, Rapp CR, Olli KE, Perrenoud L, Jedlicka P, Bowser JL, Mills TW, Karmouty-Quintana H, Blackburn MR, Eltzschig HK. Coordination of ENT2-dependent adenosine transport and signaling dampens mucosal inflammation. JCI Insight 2018; 3:121521. [PMID: 30333323 PMCID: PMC6237472 DOI: 10.1172/jci.insight.121521] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Accepted: 08/30/2018] [Indexed: 12/19/2022] Open
Abstract
Intestinal epithelial barrier repair is vital for remission in inflammatory bowel disease (IBD). Extracellular adenosine signaling has been implicated in promoting restoration of epithelial barrier function. Currently, no clinically approved agents target this pathway. Adenosine signaling is terminated by uptake from the extracellular space via equilibrative nucleoside transporters (ENTs). We hypothesized that ENT inhibition could dampen intestinal inflammation. Initial studies demonstrated transcriptional repression of ENT1 and ENT2 in IBD biopsies or in murine IBD models. Subsequent studies in mice with global Ent1 or Ent2 deletion revealed selective protection of Ent2-/- mice. Elevated intestinal adenosine levels in conjunction with abolished protection following pharmacologic blockade of A2B adenosine receptors implicate adenosine signaling as the mechanism of gut protection in Ent2-/- mice. Additional studies in mice with tissue-specific deletion of Ent2 uncovered epithelial Ent2 as the target. Moreover, intestinal protection provided by a selective Ent2 inhibitor was abolished in mice with epithelium-specific deletion of Ent2 or the A2B adenosine receptor. Taken together, these findings indicate that increased mucosal A2B signaling following repression or deletion of epithelial Ent2 coordinates the resolution of intestinal inflammation. This study suggests the presence of a targetable purinergic network within the intestinal epithelium designed to limit tissue inflammation.
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Affiliation(s)
- Carol M. Aherne
- Department of Anesthesiology, and
- Mucosal Inflammation Program, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Colm B. Collins
- Mucosal Inflammation Program, University of Colorado School of Medicine, Aurora, Colorado, USA
- Department of Pediatrics, Division of Gastroenterology, Hepatology and Nutrition, Digestive Health Institute, Children’s Hospital Colorado, Aurora, Colorado, USA
| | - Caroline R. Rapp
- Department of Anesthesiology, and
- Mucosal Inflammation Program, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Kristine E. Olli
- Department of Anesthesiology, and
- Mucosal Inflammation Program, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Loni Perrenoud
- Department of Anesthesiology, and
- Mucosal Inflammation Program, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Paul Jedlicka
- Department of Pathology, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Jessica L. Bowser
- Department of Anesthesiology, McGovern Medical School at UTHealth, Houston, Texas, USA
| | - Tingting W. Mills
- Department of Biochemistry and Molecular Biology, McGovern Medical School at UTHealth, Houston, Texas, USA
| | - Harry Karmouty-Quintana
- Department of Biochemistry and Molecular Biology, McGovern Medical School at UTHealth, Houston, Texas, USA
| | - Michael R. Blackburn
- Department of Biochemistry and Molecular Biology, McGovern Medical School at UTHealth, Houston, Texas, USA
| | - Holger K. Eltzschig
- Department of Anesthesiology, and
- Department of Anesthesiology, McGovern Medical School at UTHealth, Houston, Texas, USA
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Oda K, Mori N, Okumi M, Furusawa M, Ishiguro M, Inoue K, Shuto S, Unagami K, Ishida H, Tanabe K, Murakami T. Uptake and metabolism of mizoribine, an immunosuppressant, in L5178Y-R mouse lymphoma cells in vitro and peripheral blood mononuclear cells of rats and kidney transplant recipients in vivo. Drug Metab Pharmacokinet 2018; 33:232-239. [PMID: 30241694 DOI: 10.1016/j.dmpk.2018.08.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 07/29/2018] [Accepted: 08/20/2018] [Indexed: 12/28/2022]
Abstract
The cellular uptake of mizoribine (MZR), an immunosuppressant, and metabolism of MZR to MZR-5'- monophosphate (MZRP), an active metabolite, were evaluated in L5178Y-R mouse lymphoma cells and peripheral blood mononuclear cells (PBMCs) of rats and kidney transplant recipients (KTRs, n = 22). Real-time PCR analysis revealed the expression of ENT1 and ENT2 mRNAs, but not of CNTs, in L5178Y-R cells and rat's PBMCs. In L5178Y-R cells, the uptake of MZR was suppressed by adenosine, a substrate for ENT1 and ENT2, but not by 5-(4-nitrobenzyl)-6-thioinosine (0.1 μM), an ENT1 inhibitor. Saturable metabolism of MZR to MZRP was observed. In rats, peak plasma concentrations of MZR and peak concentrations of MZR and MZRP in PBMCs were observed 3 h after oral administration. MZR disappeared from PBMCs in parallel with plasma MZR, but the disappearance of MZRP from PBMCs appeared to be slow. In KTRs, the mean plasma concentration of MZR 3-4 h after ingestion was 3.14 μg/ml and the mean MZRP concentration in PBMCs was 16.8% of MZR, reflecting the involvement of ENT in the uptake of MZR. A linear relationship was observed between plasma MZR concentrations ranging from 1 to 6 μg/ml and PBMC's MZRP concentrations ranging from 90 to 200 ng/ml.
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Affiliation(s)
- Keisuke Oda
- Laboratory of Biopharmaceutics and Pharmacokinetics, Faculty of Pharmaceutical Sciences, Hiroshima International University, 5-1-1 Hiro-koshingai, Kure, Hiroshima 737-0112, Japan.
| | - Nobuhiro Mori
- Laboratory of Biopharmaceutics and Pharmacokinetics, Faculty of Pharmaceutical Sciences, Hiroshima International University, 5-1-1 Hiro-koshingai, Kure, Hiroshima 737-0112, Japan
| | - Masayoshi Okumi
- Department of Urology, Tokyo Women's Medical University, 8-1 Kawada-cho, Shinjuku, Tokyo 162-8666, Japan
| | - Miyuki Furusawa
- Department of Urology, Tokyo Women's Medical University, 8-1 Kawada-cho, Shinjuku, Tokyo 162-8666, Japan
| | - Masashi Ishiguro
- Laboratory for Safety Assessment and ADME, Pharmaceuticals Research Center, Asahi Kasei Pharma Corporation, 632-1 Mifuku, Izunokunishi, Shizuoka 410-2321, Japan
| | - Kazuyuki Inoue
- Medical Affairs Department, Pharmaceutical Business Administration Division, Asahi Kasei Pharma Corporation, 1-105 Kanda Jimbocho, Chiyoda-ku, Tokyo 101-8101, Japan
| | - Satoshi Shuto
- Graduate School of Pharmaceutical Sciences, Hokkaido University, Kita-12, Nishi-6, Kita-ku, Sapporo 060-0812, Japan
| | - Kohei Unagami
- Department of Nephrology, Tokyo Women's Medical University, Yocho-machi Clinic, Yocho-machi 6-21, Shinjuku, Tokyo 162-0055, Japan
| | - Hideki Ishida
- Department of Urology, Tokyo Women's Medical University, 8-1 Kawada-cho, Shinjuku, Tokyo 162-8666, Japan
| | - Kazunari Tanabe
- Department of Urology, Tokyo Women's Medical University, 8-1 Kawada-cho, Shinjuku, Tokyo 162-8666, Japan
| | - Teruo Murakami
- Laboratory of Biopharmaceutics and Pharmacokinetics, Faculty of Pharmaceutical Sciences, Hiroshima International University, 5-1-1 Hiro-koshingai, Kure, Hiroshima 737-0112, Japan
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36
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Pastor-Anglada M, Urtasun N, Pérez-Torras S. Intestinal Nucleoside Transporters: Function, Expression, and Regulation. Compr Physiol 2018; 8:1003-1017. [PMID: 29978890 DOI: 10.1002/cphy.c170039] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The gastrointestinal tract is the absorptive organ for nutrients found in foods after digestion. Nucleosides and, to a lesser extent nucleobases, are the late products of nucleoprotein digestion. These metabolites are absorbed by nucleoside (and nucleobase) transporter (NT) proteins. NTs are differentially distributed along the gastrointestinal tract showing also polarized expression in epithelial cells. Concentrative nucleoside transporters (CNTs) are mainly located at the apical side of enterocytes, whereas equilibrative nucleoside transporters (ENTs) facilitate the basolateral efflux of nucleosides and nucleobases to the bloodstream. Moreover, selected nucleotides and the bioactive nucleoside adenosine act directly on intestinal cells modulating purinergic signaling. NT-polarized insertion is tightly regulated. However, not much is known about the modulation of intestinal NT function in humans, probably due to the lack of appropriate cell models retaining CNT functional expression. Thus, the possibility of nutritional regulation of intestinal NTs has been addressed using animal models. Besides the nutrition-related role of NT proteins, orally administered drugs also need to cross the intestinal barrier, this event being a major determinant of drug bioavailability. In this regard, NT proteins might also play a role in pharmacology, thereby allowing the absorption of nucleoside- and nucleobase-derived drugs. The relative broad selectivity of these membrane transporters also suggests clinically relevant drug-drug interactions when using combined therapies. This review focuses on all these physiological and pharmacological aspects of NT protein biology. © 2017 American Physiological Society. Compr Physiol 8:1003-1017, 2018.
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Affiliation(s)
- Marçal Pastor-Anglada
- Biochemistry and Molecular Pharmacology Section, Department of Biochemistry and Molecular Biomedicine, Institute of Biomedicine (IBUB), University of Barcelona, Barcelona, Spain.,Oncology Program, National Biomedical Research Institute on Liver and Gastrointestinal Diseases (CIBER EHD), Instituto de Salud Carlos III, Barcelona, Spain.,Genetics, Molecular Biology and Gene Therapy Program, Institut de Recerca Sant Joan de Déu (IR SJD), Esplugues de Llobregat, Barcelona, Spain
| | - Nerea Urtasun
- Biochemistry and Molecular Pharmacology Section, Department of Biochemistry and Molecular Biomedicine, Institute of Biomedicine (IBUB), University of Barcelona, Barcelona, Spain.,Oncology Program, National Biomedical Research Institute on Liver and Gastrointestinal Diseases (CIBER EHD), Instituto de Salud Carlos III, Barcelona, Spain.,Genetics, Molecular Biology and Gene Therapy Program, Institut de Recerca Sant Joan de Déu (IR SJD), Esplugues de Llobregat, Barcelona, Spain
| | - Sandra Pérez-Torras
- Biochemistry and Molecular Pharmacology Section, Department of Biochemistry and Molecular Biomedicine, Institute of Biomedicine (IBUB), University of Barcelona, Barcelona, Spain.,Oncology Program, National Biomedical Research Institute on Liver and Gastrointestinal Diseases (CIBER EHD), Instituto de Salud Carlos III, Barcelona, Spain.,Genetics, Molecular Biology and Gene Therapy Program, Institut de Recerca Sant Joan de Déu (IR SJD), Esplugues de Llobregat, Barcelona, Spain
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Pastor-Anglada M, Pérez-Torras S. Who Is Who in Adenosine Transport. Front Pharmacol 2018; 9:627. [PMID: 29962948 PMCID: PMC6010718 DOI: 10.3389/fphar.2018.00627] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Accepted: 05/24/2018] [Indexed: 12/13/2022] Open
Abstract
Extracellular adenosine concentrations are regulated by a panel of membrane transporters which, in most cases, mediate its uptake into cells. Adenosine transporters belong to two gene families encoding Equilibrative and Concentrative Nucleoside Transporter proteins (ENTs and CNTs, respectively). The lack of appropriate pharmacological tools targeting every transporter subtype has introduced some bias on the current knowledge of the role of these transporters in modulating adenosine levels. In this regard, ENT1, for which pharmacology is relatively well-developed, has often been identified as a major player in purinergic signaling. Nevertheless, other transporters such as CNT2 and CNT3 can also contribute to purinergic modulation based on their high affinity for adenosine and concentrative capacity. Moreover, both transporter proteins have also been shown to be under purinergic regulation via P1 receptors in different cell types, which further supports its relevance in purinergic signaling. Thus, several transporter proteins regulate extracellular adenosine levels. Moreover, CNT and ENT proteins are differentially expressed in tissues but also in particular cell types. Accordingly, transporter-mediated fine tuning of adenosine levels is cell and tissue specific. Future developments focusing on CNT pharmacology are needed to unveil transporter subtype-specific events.
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Affiliation(s)
- Marçal Pastor-Anglada
- Molecular Pharmacology and Experimental Therapeutics, Department of Biochemistry and Molecular Biomedicine, Institute of Biomedicine, University of Barcelona, Barcelona, Spain
- Oncology Program, National Biomedical Research Institute on Liver and Gastrointestinal Diseases – CIBER ehd, Institut de Recerca Sant Joan de Déu, Barcelona, Spain
| | - Sandra Pérez-Torras
- Molecular Pharmacology and Experimental Therapeutics, Department of Biochemistry and Molecular Biomedicine, Institute of Biomedicine, University of Barcelona, Barcelona, Spain
- Oncology Program, National Biomedical Research Institute on Liver and Gastrointestinal Diseases – CIBER ehd, Institut de Recerca Sant Joan de Déu, Barcelona, Spain
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38
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Pastor-Anglada M, Pérez-Torras S. Emerging Roles of Nucleoside Transporters. Front Pharmacol 2018; 9:606. [PMID: 29928232 PMCID: PMC5997781 DOI: 10.3389/fphar.2018.00606] [Citation(s) in RCA: 95] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Accepted: 05/21/2018] [Indexed: 01/02/2023] Open
Abstract
Since human Nucleoside Transporters (hNTs) were identified by their activity as transport systems, extensive work has been done to fully characterize them at the molecular and physiological level. Many efforts have been addressed to the identification of their selectivity for natural substrates and nucleoside analogs used to treat several diseases. hNTs belong to two different gene families, SLC28 and SLC29, encoding human Concentrative Nucleoside Transporters (hCNTs) and human Equilibrative Nucleoside Transporters (hENTs), respectively. hCNTs and hENTs are integral membrane proteins, albeit structurally unrelated. Both families share common features as substrate selectivity and often tissue localization. This apparent biological redundancy may anticipate some different roles for hCNTs and hENTs in cell physiology. Thus, hENTs may have a major role in maintaining nucleoside homeostasis, whereas hCNTs could contribute to nucleoside sensing and signal transduction. In this sense, the ascription of hCNT1 to a transceptor reinforces this hypothesis. Moreover, some evidences could suggest a putative role of hCNT2 and hCNT3 as transceptors. The interacting proteins identified for hCNT2 suggest a link to energy metabolism. Moreover, the ability of hCNT2 and hCNT3 to transport adenosine links both proteins to purinergic signaling. On the other hand, the broad selectivity transporters hENTs have a crucial role in salvage pathways and purinergic signaling by means of nucleoside pools regulation. In particular, the two new hENT2 isoforms recently described together with hENT2 seem to be key elements controlling nucleoside and nucleotide pools for DNA synthesis. This review focuses on all these NTs functions beyond their mere translocation ability.
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Affiliation(s)
- Marçal Pastor-Anglada
- Biochemistry and Molecular Pharmacology Section, Department of Biochemistry and Molecular Biomedicine, Institute of Biomedicine (IBUB), University of Barcelona, Barcelona, Spain
| | - Sandra Pérez-Torras
- Biochemistry and Molecular Pharmacology Section, Department of Biochemistry and Molecular Biomedicine, Institute of Biomedicine (IBUB), University of Barcelona, Barcelona, Spain
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39
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Jiraskova L, Cerveny L, Karbanova S, Ptackova Z, Staud F. Expression of Concentrative Nucleoside Transporters ( SLC28A) in the Human Placenta: Effects of Gestation Age and Prototype Differentiation-Affecting Agents. Mol Pharm 2018; 15:2732-2741. [PMID: 29782174 DOI: 10.1021/acs.molpharmaceut.8b00238] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Equilibrative ( SLC29A) and concentrative ( SLC28A) nucleoside transporters contribute to proper placental development and mediate uptake of nucleosides/nucleoside-derived drugs. We analyzed placental expression of SLC28A mRNA during gestation. Moreover, we studied in choriocarcinoma-derived BeWo cells whether SLC29A and SLC28A mRNA levels can be modulated by activity of adenylyl cyclase, retinoic acid receptor activation, CpG islands methylation, or histone acetylation, using forskolin, all- trans-retinoic acid, 5-azacytidine, and sodium butyrate/sodium valproate, respectively. We found that expression of SLC28A1, SLC28A2, and SLC28A3 increases during gestation and reveals considerable interindividual variability. SLC28A2 was shown to be a dominant subtype in the first-trimester and term human placenta, while SLC28A1 exhibited negligible expression in the term placenta only. In BeWo cells, we detected mRNA of SLC28A2 and SLC28A3. Levels of the latter were affected by 5-azacytidine and all- trans-retinoic acid, while the former was modulated by sodium valproate (but not sodium butyrate), all- trans-retinoic acid, 5-azacytidine, and forskolin that caused 25-fold increase in SLC28A2 mRNA; we documented by analysis of syncytin-1 that the observed changes in SLC28A expression do not correlate with the morphological differentiation state of BeWo cells. Upregulated SLC28A2 mRNA was reflected in elevated uptake of [3H]-adenosine, high-affinity substrate of concentrative nucleoside transporter 2. Using KT-5720 and inhibitors of phosphodiesterases, we subsequently confirmed importance of cAMP/protein kinase A pathway in SLC28A2 regulation. On the other hand, SLC29A genes exhibited constitutive expression and none of the tested compounds increased SLC28A1 expression to detectable levels. In conclusion, we provide the first evidence that methylation status and activation of retinoic acid receptor affect placental SLC28A2 and SLC28A3 transcription and substrates of concentrative nucleoside transporter 2 might be taken up in higher extent in placentas with overactivated cAMP/protein kinase A pathway and likely in the term placenta.
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Affiliation(s)
- Lucie Jiraskova
- Department of Pharmacology and Toxicology , Charles University, Faculty of Pharmacy in Hradec Kralove , Akademika Heyrovskeho 1203 , 50005 Hradec Kralove , Czech Republic
| | - Lukas Cerveny
- Department of Pharmacology and Toxicology , Charles University, Faculty of Pharmacy in Hradec Kralove , Akademika Heyrovskeho 1203 , 50005 Hradec Kralove , Czech Republic
| | - Sara Karbanova
- Department of Pharmacology and Toxicology , Charles University, Faculty of Pharmacy in Hradec Kralove , Akademika Heyrovskeho 1203 , 50005 Hradec Kralove , Czech Republic
| | - Zuzana Ptackova
- Department of Pharmacology and Toxicology , Charles University, Faculty of Pharmacy in Hradec Kralove , Akademika Heyrovskeho 1203 , 50005 Hradec Kralove , Czech Republic
| | - Frantisek Staud
- Department of Pharmacology and Toxicology , Charles University, Faculty of Pharmacy in Hradec Kralove , Akademika Heyrovskeho 1203 , 50005 Hradec Kralove , Czech Republic
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40
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Intracellular acidification reduces l-arginine transport via system y+L but not via system y+/CATs and nitric oxide synthase activity in human umbilical vein endothelial cells. Biochim Biophys Acta Mol Basis Dis 2018; 1864:1192-1202. [DOI: 10.1016/j.bbadis.2018.01.032] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Revised: 01/15/2018] [Accepted: 01/31/2018] [Indexed: 12/13/2022]
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41
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Boswell-Casteel RC, Johnson JM, Roe-Žurž Z, Duggan KD, Schmitz H, Hays FA. Expression and purification of human and Saccharomyces cerevisiae equilibrative nucleoside transporters. Protein Expr Purif 2017; 142:68-74. [PMID: 28918196 DOI: 10.1016/j.pep.2017.09.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Revised: 09/05/2017] [Accepted: 09/05/2017] [Indexed: 01/09/2023]
Abstract
Nucleosides play an essential role in the physiology of eukaryotes by acting as metabolic precursors in de novo nucleic acid synthesis and energy metabolism. Nucleosides also act as ligands for purinergic receptors. Equilibrative nucleoside transporters (ENTs) are polytopic integral membrane proteins that aid in regulating plasmalemmal flux of purine and pyrimidine nucleosides and nucleobases. ENTs exhibit broad substrate selectivity across different isoforms and utilize diverse mechanisms to drive substrate flux across membranes. However, the molecular mechanisms and chemical determinants of ENT-mediated substrate recognition, binding, inhibition, and transport are poorly understood. To determine how ENT-mediated transport occurs at the molecular level, greater chemical insight and assays employing purified protein are essential. This article focuses on the expression and purification of human ENT1, human ENT2, and Saccharomyces cerevisiae ScENT1 using novel expression and purification strategies to isolate recombinant ENTs. ScENT1, hENT1, and hENT2 were expressed in W303 Saccharomyces cerevisiae cells and detergent solubilized from the membrane. After detergent extraction, these ENTs were further purified using immobilized metal affinity chromatography and size exclusion chromatography. This effort resulted in obtaining quantities of purified protein sufficient for future biophysical analysis.
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Affiliation(s)
- Rebba C Boswell-Casteel
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Jennifer M Johnson
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Zygy Roe-Žurž
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, CA 94143, USA
| | - Kelli D Duggan
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Hannah Schmitz
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Franklin A Hays
- Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; Stephenson Oklahoma Cancer Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; Harold Hamm Diabetes Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA.
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42
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Rahman MF, Askwith C, Govindarajan R. Molecular determinants of acidic pH-dependent transport of human equilibrative nucleoside transporter 3. J Biol Chem 2017; 292:14775-14785. [PMID: 28729424 DOI: 10.1074/jbc.m117.787952] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Revised: 07/11/2017] [Indexed: 12/16/2022] Open
Abstract
Equilibrative nucleoside transporters (ENTs) translocate hydrophilic nucleosides across cellular membranes and are essential for salvage nucleotide synthesis and purinergic signaling. Unlike the prototypic human ENT members hENT1 and hENT2, which mediate plasma membrane nucleoside transport at pH 7.4, hENT3 is an acidic pH-activated lysosomal transporter partially localized to mitochondria. Recent studies demonstrate that hENT3 is indispensable for lysosomal homeostasis, and that mutations in hENT3 can result in a spectrum of lysosomal storage-like disorders. However, despite hENT3's prominent role in lysosome pathophysiology, the molecular basis of hENT3-mediated transport is unknown. Therefore, we sought to examine the mechanistic basis of acidic pH-driven hENT3 nucleoside transport with site-directed mutagenesis, homology modeling, and [3H]adenosine flux measurements in mutant RNA-injected Xenopus oocytes. Scanning mutagenesis of putative residues responsible for pH-dependent transport via hENT3 revealed that the ionization states of Asp-219 and Glu-447, and not His, strongly determined the pH-dependent transport permissible-impermissible states of the transporter. Except for substitution with certain isosteric and polar residues, substitution of either Asp-219 or Glu-447 with any other residues resulted in robust activity that was pH-independent. Dual substitution of Asp-219 and Glu-447 to Ala sustained pH-independent activity over a broad range of physiological pH (pH 5.5-7.4), which also maintained stringent substrate selectivity toward endogenous nucleosides and clinically used nucleoside drugs. Our results suggest a putative pH-sensing role for Asp-219 and Glu-447 in hENT3 and that the size, ionization state, or electronegative polarity at these positions is crucial for obligate acidic pH-dependent activity.
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Affiliation(s)
- Md Fazlur Rahman
- From the Division of Pharmaceutics and Pharmaceutical Chemistry, College of Pharmacy
| | | | - Rajgopal Govindarajan
- From the Division of Pharmaceutics and Pharmaceutical Chemistry, College of Pharmacy, .,the Translational Therapeutics Program, Ohio State University Comprehensive Cancer Center, Ohio State University, Columbus, Ohio 43210
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43
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The SLC28 (CNT) and SLC29 (ENT) nucleoside transporter families: a 30-year collaborative odyssey. Biochem Soc Trans 2017; 44:869-76. [PMID: 27284054 DOI: 10.1042/bst20160038] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Indexed: 01/18/2023]
Abstract
Specialized nucleoside transporter (NT) proteins are required for passage of nucleosides and hydrophilic nucleoside analogues across biological membranes. Physiologic nucleosides serve as central salvage metabolites in nucleotide biosynthesis, and nucleoside analogues are used as chemotherapeutic agents in the treatment of cancer and antiviral diseases. The nucleoside adenosine modulates numerous cellular events via purino-receptor cell signalling pathways. Human NTs are divided into two structurally unrelated protein families: the SLC28 concentrative nucleoside transporter (CNT) family and the SLC29 equilibrative nucleoside transporter (ENT) family. Human CNTs are inwardly directed Na(+)-dependent nucleoside transporters found predominantly in intestinal and renal epithelial and other specialized cell types. Human ENTs mediate bidirectional fluxes of purine and pyrimidine nucleosides down their concentration gradients and are ubiquitously found in most, possibly all, cell types. Both protein families are evolutionarily old: CNTs are present in both eukaryotes and prokaryotes; ENTs are widely distributed in mammalian, lower vertebrate and other eukaryote species. This mini-review describes a 30-year collaboration with Professor Stephen Baldwin to identify and understand the structures and functions of these physiologically and clinically important transport proteins.
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44
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Silva L, Subiabre M, Araos J, Sáez T, Salsoso R, Pardo F, Leiva A, San Martín R, Toledo F, Sobrevia L. Insulin/adenosine axis linked signalling. Mol Aspects Med 2017; 55:45-61. [DOI: 10.1016/j.mam.2016.11.002] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2016] [Revised: 11/16/2016] [Accepted: 11/17/2016] [Indexed: 12/22/2022]
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45
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Leiva A, Guzmán-Gutiérrez E, Contreras-Duarte S, Fuenzalida B, Cantin C, Carvajal L, Salsoso R, Gutiérrez J, Pardo F, Sobrevia L. Adenosine receptors: Modulators of lipid availability that are controlled by lipid levels. Mol Aspects Med 2017; 55:26-44. [DOI: 10.1016/j.mam.2017.01.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2016] [Revised: 01/25/2017] [Accepted: 01/25/2017] [Indexed: 12/20/2022]
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46
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Huang W, Zeng X, Shi Y, Liu M. Functional characterization of human equilibrative nucleoside transporter 1. Protein Cell 2017; 8:284-295. [PMID: 27995448 PMCID: PMC5359181 DOI: 10.1007/s13238-016-0350-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Accepted: 11/04/2016] [Indexed: 12/15/2022] Open
Abstract
Equilibrative nucleoside transporters (ENTs), which facilitate cross-membrane transport of nucleosides and nucleoside-derived drugs, play an important role in the salvage pathways of nucleotide synthesis, cancer chemotherapy, and treatment for virus infections. Functional characterization of ENTs at the molecular level remains technically challenging and hence scant. In this study, we report successful purification and biochemical characterization of human equilibrative nucleoside transporter 1 (hENT1) in vitro. The HEK293F-derived, recombinant hENT1 is homogenous and functionally active in proteoliposome-based counter flow assays. hENT1 transports the substrate adenosine with a Km of 215 ± 34 µmol/L and a Vmax of 578 ± 23.4 nmol mg-1 min-1. Adenosine uptake by hENT1 is competitively inhibited by nitrobenzylmercaptopurine ribonucleoside (NBMPR), nucleosides, deoxynucleosides, and nucleoside-derived anti-cancer and anti-viral drugs. Binding of hENT1 to adenosine, deoxyadenosine, and adenine by isothermal titration calorimetry is in general agreement with results of the competitive inhibition assays. These results validate hENT1 as a bona fide target for potential drug target and serve as a useful basis for future biophysical and structural studies.
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Affiliation(s)
- Weiyun Huang
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Xin Zeng
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Yigong Shi
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Minhao Liu
- Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, 100084, China.
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Celis N, Araos J, Sanhueza C, Toledo F, Beltrán AR, Pardo F, Leiva A, Ramírez MA, Sobrevia L. Intracellular acidification increases adenosine transport in human umbilical vein endothelial cells. Placenta 2017; 51:10-17. [DOI: 10.1016/j.placenta.2017.01.120] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 01/01/2017] [Accepted: 01/14/2017] [Indexed: 12/16/2022]
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48
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Zhong XZ, Zou Y, Sun X, Dong G, Cao Q, Pandey A, Rainey JK, Zhu X, Dong XP. Inhibition of Transient Receptor Potential Channel Mucolipin-1 (TRPML1) by Lysosomal Adenosine Involved in Severe Combined Immunodeficiency Diseases. J Biol Chem 2017; 292:3445-3455. [PMID: 28087698 DOI: 10.1074/jbc.m116.743963] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Revised: 01/09/2017] [Indexed: 11/06/2022] Open
Abstract
Impaired adenosine homeostasis has been associated with numerous human diseases. Lysosomes are referred to as the cellular recycling centers that generate adenosine by breaking down nucleic acids or ATP. Recent studies have suggested that lysosomal adenosine overload causes lysosome defects that phenocopy patients with mutations in transient receptor potential channel mucolipin-1 (TRPML1), a lysosomal Ca2+ channel, suggesting that lysosomal adenosine overload may impair TRPML1 and then lead to subsequent lysosomal dysfunction. In this study, we demonstrate that lysosomal adenosine is elevated by deleting adenosine deaminase (ADA), an enzyme responsible for adenosine degradation. We also show that lysosomal adenosine accumulation inhibits TRPML1, which is rescued by overexpressing ENT3, the adenosine transporter situated in the lysosome membrane. Moreover, ADA deficiency results in lysosome enlargement, alkalinization, and dysfunction. These are rescued by activating TRPML1. Importantly, ADA-deficient B-lymphocytes are more vulnerable to oxidative stress, and this was rescued by TRPML1 activation. Our data suggest that lysosomal adenosine accumulation impairs lysosome function by inhibiting TRPML1 and subsequently leads to cell death in B-lymphocytes. Activating TRPML1 could be a new therapeutic strategy for those diseases.
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Affiliation(s)
| | | | - Xue Sun
- Departments of Physiology and Biophysics; Key Laboratory of Molecular Epigenetics of Ministry of Education, Institute of Cytology and Genetics, Northeast Normal University, Changchun, 130024 Jilin, China
| | | | - Qi Cao
- Departments of Physiology and Biophysics
| | - Aditya Pandey
- Biochemistry and Molecular Biology, Dalhousie University, Sir Charles Tupper Medical Building, 5850 College Street, Halifax, Nova Scotia B3H 4R2, Canada
| | - Jan K Rainey
- Biochemistry and Molecular Biology, Dalhousie University, Sir Charles Tupper Medical Building, 5850 College Street, Halifax, Nova Scotia B3H 4R2, Canada; Department of Chemistry, Dalhousie University, 6274 Coburg Road, Halifax, Nova Scotia B3H 4R2, Canada
| | - Xiaojuan Zhu
- Key Laboratory of Molecular Epigenetics of Ministry of Education, Institute of Cytology and Genetics, Northeast Normal University, Changchun, 130024 Jilin, China
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Boswell-Casteel RC, Hays FA. Equilibrative nucleoside transporters-A review. NUCLEOSIDES NUCLEOTIDES & NUCLEIC ACIDS 2016; 36:7-30. [PMID: 27759477 DOI: 10.1080/15257770.2016.1210805] [Citation(s) in RCA: 125] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Equilibrative nucleoside transporters (ENTs) are polytopic integral membrane proteins that mediate the transport of nucleosides, nucleobases, and therapeutic analogs. The best-characterized ENTs are the human transporters hENT1 and hENT2. However, non-mammalian eukaryotic ENTs have also been studied (e.g., yeast, parasitic protozoa). ENTs are major pharmaceutical targets responsible for modulating the efficacy of more than 30 approved drugs. However, the molecular mechanisms and chemical determinants of ENT-mediated substrate recognition, binding, inhibition, and transport are poorly understood. This review highlights findings on the characterization of ENTs by surveying studies on genetics, permeant and inhibitor interactions, mutagenesis, and structural models of ENT function.
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Affiliation(s)
- Rebba C Boswell-Casteel
- a Department of Biochemistry and Molecular Biology , University of Oklahoma Health Sciences Center , Oklahoma City , OK , USA
| | - Franklin A Hays
- a Department of Biochemistry and Molecular Biology , University of Oklahoma Health Sciences Center , Oklahoma City , OK , USA.,b Stephenson Cancer Center , University of Oklahoma Health Sciences Center , Oklahoma City , OK , USA.,c Harold Hamm Diabetes Center , University of Oklahoma Health Sciences Center , Oklahoma City , OK , USA
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50
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Wang J. The plasma membrane monoamine transporter (PMAT): Structure, function, and role in organic cation disposition. Clin Pharmacol Ther 2016; 100:489-499. [PMID: 27506881 DOI: 10.1002/cpt.442] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Accepted: 07/25/2016] [Indexed: 12/25/2022]
Abstract
Plasma membrane monoamine transporter (PMAT) is a new polyspecific organic cation transporter that transports a variety of biogenic amines and xenobiotic cations. Highly expressed in the brain, PMAT represents a major uptake2 transporter for monoamine neurotransmitters. At the blood-cerebrospinal fluid (CSF) barrier, PMAT is the principal organic cation transporter for removing neurotoxins and drugs from the CSF. Here I summarize our latest understanding of PMAT and its roles in monoamine uptake and xenobiotic disposition.
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Affiliation(s)
- J Wang
- Department of Pharmaceutics, University of Washington, Seattle, Washington, USA.
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