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Knippenberg N, Bauwens M, Schijns O, Hoogland G, Florea A, Rijkers K, Cleij TJ, Eersels K, van Grinsven B, Diliën H. Visualizing GABA transporters in vivo: an overview of reported radioligands and future directions. EJNMMI Res 2023; 13:42. [PMID: 37171631 PMCID: PMC10182260 DOI: 10.1186/s13550-023-00992-5] [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: 03/23/2023] [Accepted: 05/02/2023] [Indexed: 05/13/2023] Open
Abstract
By clearing GABA from the synaptic cleft, GABA transporters (GATs) play an essential role in inhibitory neurotransmission. Consequently, in vivo visualization of GATs can be a valuable diagnostic tool and biomarker for various psychiatric and neurological disorders. Not surprisingly, in recent years several research attempts to develop a radioligand have been conducted, but so far none have led to suitable radioligands that allow imaging of GATs. Here, we provide an overview of the radioligands that were developed with a focus on GAT1, since this is the most abundant transporter and most of the research concerns this GAT subtype. Initially, we focus on the field of GAT1 inhibitors, after which we discuss the development of GAT1 radioligands based on these inhibitors. We hypothesize that the radioligands developed so far have been unsuccessful due to the zwitterionic nature of their nipecotic acid moiety. To overcome this problem, the use of non-classical GAT inhibitors as basis for GAT1 radioligands or the use of carboxylic acid bioisosteres may be considered. As the latter structural modification has already been used in the field of GAT1 inhibitors, this option seems particularly viable and could lead to the development of more successful GAT1 radioligands in the future.
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Affiliation(s)
- Niels Knippenberg
- Sensor Engineering Department, Faculty of Science and Engineering, Maastricht University, 6200 MD, Maastricht, The Netherlands.
| | - Matthias Bauwens
- Department of Nuclear Medicine, University Hospital Aachen, RWTH Aachen University, 52074, Aachen, Germany
- Department of Radiology and Nuclear Medicine, Maastricht University Medical Centre+ (MUMC+), 6229 HX, Maastricht, The Netherlands
| | - Olaf Schijns
- Department of Neurosurgery, Maastricht University Medical Centre+ (MUMC+), 6229 HX, Maastricht, The Netherlands
- School for Mental Health and Neuroscience (MHeNS), Maastricht University, 6200 MD, Maastricht, The Netherlands
- Academic Center for Epileptology (ACE), Maastricht University Medical Centre+ (MUMC+), 6229 HX, Maastricht, The Netherlands
| | - Govert Hoogland
- Department of Neurosurgery, Maastricht University Medical Centre+ (MUMC+), 6229 HX, Maastricht, The Netherlands
- School for Mental Health and Neuroscience (MHeNS), Maastricht University, 6200 MD, Maastricht, The Netherlands
| | - Alexandru Florea
- Department of Nuclear Medicine, University Hospital Aachen, RWTH Aachen University, 52074, Aachen, Germany
- Department of Radiology and Nuclear Medicine, Maastricht University Medical Centre+ (MUMC+), 6229 HX, Maastricht, The Netherlands
- School for Cardiovascular Diseases (CARIM), Maastricht University Medical Centre+ (MUMC+), 6229 HX, Maastricht, The Netherlands
| | - Kim Rijkers
- Department of Neurosurgery, Maastricht University Medical Centre+ (MUMC+), 6229 HX, Maastricht, The Netherlands
- School for Mental Health and Neuroscience (MHeNS), Maastricht University, 6200 MD, Maastricht, The Netherlands
- Academic Center for Epileptology (ACE), Maastricht University Medical Centre+ (MUMC+), 6229 HX, Maastricht, The Netherlands
| | - Thomas J Cleij
- Sensor Engineering Department, Faculty of Science and Engineering, Maastricht University, 6200 MD, Maastricht, The Netherlands
| | - Kasper Eersels
- Sensor Engineering Department, Faculty of Science and Engineering, Maastricht University, 6200 MD, Maastricht, The Netherlands
| | - Bart van Grinsven
- Sensor Engineering Department, Faculty of Science and Engineering, Maastricht University, 6200 MD, Maastricht, The Netherlands
| | - Hanne Diliën
- Sensor Engineering Department, Faculty of Science and Engineering, Maastricht University, 6200 MD, Maastricht, The Netherlands
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Zhang G, Guo M, Ma H, Wang J, Zhang XD. Catalytic nanotechnology of X-ray photodynamics for cancer treatments. Biomater Sci 2023; 11:1153-1181. [PMID: 36602259 DOI: 10.1039/d2bm01698b] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Photodynamic therapy (PDT) has been applied in cancer treatment because of its high selectivity, low toxicity, and non-invasiveness. However, the limited penetration depth of the light still hampers from reaching deep-seated tumors. Considering the penetrating ability of high-energy radiotherapy, X-ray-induced photodynamic therapy (X-PDT) has evolved as an alternative to overcome tissue blocks. As the basic principle of X-PDT, X-rays stimulate the nanoparticles to emit scintillating or persistent luminescence and further activate the photosensitizers to generate reactive oxygen species (ROS), which would cause a series of molecular and cellular damages, immune response, and eventually break down the tumor tissue. In recent years, catalytic nanosystems with unique structures and functions have emerged that can enhance X-PDT therapeutic effects via an immune response. The anti-cancer effect of X-PDT is closely related to the following factors: energy conversion efficiency of the material, the radiation dose of X-rays, quantum yield of the material, tumor resistance, and biocompatibility. Based on the latest research in this field and the classical theories of nanoscience, this paper systematically elucidates the current development of the X-PDT and related immunotherapy, and highlights its broad prospects in medical applications, discussing the connection between fundamental science and clinical translation.
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Affiliation(s)
- Gang Zhang
- Department of Physics, School of Science, Tianjin Chengjian University, Tianjin 300384, China.
| | - Meili Guo
- Department of Physics, School of Science, Tianjin Chengjian University, Tianjin 300384, China.
| | - Huizhen Ma
- Department of Physics and Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparing Technology, School of Sciences, Tianjin University, Tianjin 300350, China.
| | - Junying Wang
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA
| | - Xiao-Dong Zhang
- Department of Physics and Tianjin Key Laboratory of Low Dimensional Materials Physics and Preparing Technology, School of Sciences, Tianjin University, Tianjin 300350, China. .,Tianjin Key Laboratory of Brain Science and Neural Engineering, Academy of Medical Engineering and Translational Medicine, Tianjin University, Tianjin 300072, China
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Abstract
Membrane transporter proteins are divided into channels/pores and carriers and constitute protein families of physiological and pharmacological importance. Several presently used therapeutic compounds elucidate their effects by targeting membrane transporter proteins, including anti-arrhythmic, anesthetic, antidepressant, anxiolytic and diuretic drugs. The lack of three-dimensional structures of human transporters hampers experimental studies and drug discovery. In this chapter, the use of homology modeling for generating structural models of membrane transporter proteins is reviewed. The increasing number of atomic resolution structures available as templates, together with improvements in methods and algorithms for sequence alignments, secondary structure predictions, and model generation, in addition to the increase in computational power have increased the applicability of homology modeling for generating structural models of transporter proteins. Different pitfalls and hints for template selection, multiple-sequence alignments, generation and optimization, validation of the models, and the use of transporter homology models for structure-based virtual ligand screening are discussed.
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Affiliation(s)
- Ingebrigt Sylte
- Molecular Pharmacology and Toxicology, Department of Medical Biology, Faculty of Health Sciences, UiT The Arctic University of Norway, Tromsø, Norway.
| | - Mari Gabrielsen
- Molecular Pharmacology and Toxicology, Department of Medical Biology, Faculty of Health Sciences, UiT The Arctic University of Norway, Tromsø, Norway
| | - Kurt Kristiansen
- Molecular Pharmacology and Toxicology, Department of Medical Biology, Faculty of Health Sciences, UiT The Arctic University of Norway, Tromsø, Norway
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Bhatt M, Gauthier-Manuel L, Lazzarin E, Zerlotti R, Ziegler C, Bazzone A, Stockner T, Bossi E. A comparative review on the well-studied GAT1 and the understudied BGT-1 in the brain. Front Physiol 2023; 14:1145973. [PMID: 37123280 PMCID: PMC10137170 DOI: 10.3389/fphys.2023.1145973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Accepted: 03/30/2023] [Indexed: 05/02/2023] Open
Abstract
γ-aminobutyric acid (GABA) is the primary inhibitory neurotransmitter in the central nervous system (CNS). Its homeostasis is maintained by neuronal and glial GABA transporters (GATs). The four GATs identified in humans are GAT1 (SLC6A1), GAT2 (SLC6A13), GAT3 (SLC6A11), and betaine/GABA transporter-1 BGT-1 (SLC6A12) which are all members of the solute carrier 6 (SLC6) family of sodium-dependent transporters. While GAT1 has been investigated extensively, the other GABA transporters are less studied and their role in CNS is not clearly defined. Altered GABAergic neurotransmission is involved in different diseases, but the importance of the different transporters remained understudied and limits drug targeting. In this review, the well-studied GABA transporter GAT1 is compared with the less-studied BGT-1 with the aim to leverage the knowledge on GAT1 to shed new light on the open questions concerning BGT-1. The most recent knowledge on transporter structure, functions, expression, and localization is discussed along with their specific role as drug targets for neurological and neurodegenerative disorders. We review and discuss data on the binding sites for Na+, Cl-, substrates, and inhibitors by building on the recent cryo-EM structure of GAT1 to highlight specific molecular determinants of transporter functions. The role of the two proteins in GABA homeostasis is investigated by looking at the transport coupling mechanism, as well as structural and kinetic transport models. Furthermore, we review information on selective inhibitors together with the pharmacophore hypothesis of transporter substrates.
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Affiliation(s)
- Manan Bhatt
- Department of Biotechnology and Life Sciences, University of Insubria, Varese, Italy
- Centre for Neuroscience—University of Insubria, Varese, Italy
| | - Laure Gauthier-Manuel
- Department of Biophysics II/Structural Biology, University of Regensburg, Regensburg, Germany
| | - Erika Lazzarin
- Center for Physiology and Pharmacology, Institute of Pharmacology, Medical University of Vienna, Waehringerstr, Vienna
| | - Rocco Zerlotti
- Department of Biophysics II/Structural Biology, University of Regensburg, Regensburg, Germany
- Nanion Technologies GmbH, Munich, Germany
| | - Christine Ziegler
- Department of Biophysics II/Structural Biology, University of Regensburg, Regensburg, Germany
| | | | - Thomas Stockner
- Center for Physiology and Pharmacology, Institute of Pharmacology, Medical University of Vienna, Waehringerstr, Vienna
- *Correspondence: Thomas Stockner, ; Elena Bossi,
| | - Elena Bossi
- Department of Biotechnology and Life Sciences, University of Insubria, Varese, Italy
- Centre for Neuroscience—University of Insubria, Varese, Italy
- *Correspondence: Thomas Stockner, ; Elena Bossi,
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Schary N, Novak B, Kämper L, Yousf A, Lübbert H. Identification and pharmacological modification of resistance mechanisms to protoporphyrin-mediated photodynamic therapy in human cutaneous squamous cell carcinoma cell lines. Photodiagnosis Photodyn Ther 2022; 39:103004. [PMID: 35811052 DOI: 10.1016/j.pdpdt.2022.103004] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Revised: 06/21/2022] [Accepted: 07/06/2022] [Indexed: 10/17/2022]
Abstract
BACKGROUND Photodynamic therapy (PDT) is clinically approved to treat neoplastic skin diseases such as precursors of cutaneous squamous cell carcinoma (cSCC). In PDT, 5-aminolevulinic acid (5-ALA) drives the selective formation of the endogenous photosensitizer protoporphyrin IX (PpIX). Although 5-ALA PDT is clinically highly effective, resistance might occur due to decreased accumulation of PpIX in certain tumors. Such resistance may be caused by any fundamental step of PpIX accumulation: 5-ALA uptake, PpIX synthesis and PpIX efflux. METHODS We investigated PpIX accumulation and photodynamically induced cell death in PDT refractory SCC-13, PDT susceptible A431, and normal human epidermal keratinocytes (NHEK). Expression of genes associated with cellular PpIX kinetics was investigated on mRNA and protein level. PpIX accumulation and cell death upon illumination were pharmacologically manipulated using drugs targeting 5-ALA uptake, PpIX synthesis or efflux. RESULTS The experiments indicate that taurine transporter (SLC6A6) is the major pathway for 5-ALA uptake in cSCC cells, while being less important in NHEK. Downregulation of PpIX synthesis enzymes in SCC-13 was counteracted by methotrexate (MTX) treatment, which restored PpIX formation and cell death. PpIX efflux inhibitors targeting ABC transporters led to significantly increased PpIX accumulation in SCC-13, thereby fully overcoming resistance. CONCLUSIONS The results indicate a conserved threshold for PpIX accumulation with respect to PDT-resistance. Cells showed increased viability after PDT at PpIX concentrations below 1.5 nM. Selective uptake of 5-ALA via taurine transporter SLC6A6 in cutaneous tumor cells is novel but unrelated to resistance. MTX can partially abrogate resistance by PpIX synthesis enzyme induction, while efflux mechanisms via ABC transporters seem the main driving force and promising drug targets.
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Affiliation(s)
- Nicole Schary
- Department of Animal Physiology, Ruhr-University Bochum, Germany
| | - Ben Novak
- Department of Animal Physiology, Ruhr-University Bochum, Germany; Biofrontera Bioscience GmbH, Leverkusen, Germany.
| | - Laura Kämper
- Department of Animal Physiology, Ruhr-University Bochum, Germany
| | - Aisha Yousf
- Department of Animal Physiology, Ruhr-University Bochum, Germany
| | - Hermann Lübbert
- Department of Animal Physiology, Ruhr-University Bochum, Germany
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Ricci A, Di Pierro E, Marcacci M, Ventura P. Mechanisms of Neuronal Damage in Acute Hepatic Porphyrias. Diagnostics (Basel) 2021; 11:diagnostics11122205. [PMID: 34943446 PMCID: PMC8700611 DOI: 10.3390/diagnostics11122205] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 11/22/2021] [Accepted: 11/24/2021] [Indexed: 01/12/2023] Open
Abstract
Porphyrias are a group of congenital and acquired diseases caused by an enzymatic impairment in the biosynthesis of heme. Depending on the specific enzyme involved, different types of porphyrias (i.e., chronic vs. acute, cutaneous vs. neurovisceral, hepatic vs. erythropoietic) are described, with different clinical presentations. Acute hepatic porphyrias (AHPs) are characterized by life-threatening acute neuro-visceral crises (acute porphyric attacks, APAs), featuring a wide range of neuropathic (central, peripheral, autonomic) manifestations. APAs are usually unleashed by external "porphyrinogenic" triggers, which are thought to cause an increased metabolic demand for heme. During APAs, the heme precursors δ-aminolevulinic acid (ALA) and porphobilinogen (PBG) accumulate in the bloodstream and urine. Even though several hypotheses have been developed to explain the protean clinical picture of APAs, the exact mechanism of neuronal damage in AHPs is still a matter of debate. In recent decades, a role has been proposed for oxidative damage caused by ALA, mitochondrial and synaptic ALA toxicity, dysfunction induced by relative heme deficiency on cytochromes and other hemeproteins (i.e., nitric oxide synthases), pyridoxal phosphate functional deficiency, derangements in the metabolic pathways of tryptophan, and other factors. Since the pathway leading to the biosynthesis of heme is inscribed into a complex network of interactions, which also includes some fundamental processes of basal metabolism, a disruption in any of the steps of this pathway is likely to have multiple pathogenic effects. Here, we aim to provide a comprehensive review of the current evidence regarding the mechanisms of neuronal damage in AHPs.
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Affiliation(s)
- Andrea Ricci
- Internal Medicine Unit, Department of Medical and Surgical Science for Children and Adults, University of Modena e Reggio Emilia, 41124 Modena, Italy; (A.R.); (M.M.)
| | - Elena Di Pierro
- Dipartimento di Medicina Interna, Fondazione IRCSS Cà Granda Ospedale Maggiore Policlinico, 20122 Milan, Italy;
| | - Matteo Marcacci
- Internal Medicine Unit, Department of Medical and Surgical Science for Children and Adults, University of Modena e Reggio Emilia, 41124 Modena, Italy; (A.R.); (M.M.)
| | - Paolo Ventura
- Internal Medicine Unit, Department of Medical and Surgical Science for Children and Adults, University of Modena e Reggio Emilia, 41124 Modena, Italy; (A.R.); (M.M.)
- Correspondence: ; Tel.: +39-059-4225-542
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7
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Li B, Zhang X, Lu Y, Zhao L, Guo Y, Guo S, Kang Q, Liu J, Dai L, Zhang L, Fan D, Ji Z. Protein 4.1R affects photodynamic therapy for B16 melanoma by regulating the transport of 5-aminolevulinic acid. Exp Cell Res 2021; 399:112465. [PMID: 33385415 DOI: 10.1016/j.yexcr.2020.112465] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Revised: 12/21/2020] [Accepted: 12/24/2020] [Indexed: 12/12/2022]
Abstract
Melanoma is the most aggressive malignant tumor of skin cancer as it can grow rapidly and metastasize. Photodynamic therapy (PDT) is a promising cancer ablation method for skin tumors, although it lacks efficiency owing to factors such as tumor characteristics, delivery of photosensitizers, immune response in vivo etc. Extensive investigation of molecules that can potentially modulate treatment efficacy is required. Protein 4.1R is a cytoskeletal protein molecule. Previous studies have shown that protein 4.1R knockdown reduces PDT sensitivity in mouse embryonic fibroblast cells. However, the functional role of protein 4.1R in melanoma is unclear. In this study, we aimed to elucidate the effect of protein 4.1R on PDT for melanoma in mice and the mechanism of anti-tumor immunity. Our results indicated that CRISPR/Cas9-mediated protein 4.1R knockout promotes the proliferation, migration, and invasion of B16 cells. We further investigated the potential mechanism of protein 4.1R on tumor cell PDT sensitivity. Our results showed that protein 4.1R knockout reduced the expression of membrane transporters γ-aminobutyric acid transporter (GAT)-1 and (GAT)-2 in B16 cells, which affected 5-ALA transmembrane transport and reduced the efficiency of PDT on B16 cells. Protein 4.1R knockout downregulated the anti-tumor immune response triggered by PDT in vivo. In conclusion, our data suggest that protein 4.1R is an important regulator in PDT for tumors and may promote the progress and efficacy of melanoma treatment.
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Affiliation(s)
- Bowen Li
- Henan Institute of Medical and Pharmaceutical Sciences, Academy of Medical Science, Zhengzhou University, Zhengzhou, 450052, Henan, China
| | - Xiaolin Zhang
- People's Hospital of Zhengzhou, 33 Huanghe Road, Zhengzhou, 450000, Henan, China
| | - Yu Lu
- Henan Institute of Medical and Pharmaceutical Sciences, Academy of Medical Science, Zhengzhou University, Zhengzhou, 450052, Henan, China
| | - Luyang Zhao
- BGI College & Henan Institute of Medical and Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, 450052, Henan, China
| | - Yaxin Guo
- Henan Institute of Medical and Pharmaceutical Sciences, Academy of Medical Science, Zhengzhou University, Zhengzhou, 450052, Henan, China
| | - Shuangshuang Guo
- BGI College & Henan Institute of Medical and Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, 450052, Henan, China
| | - Qiaozhen Kang
- School of Life Sciences, Zhengzhou University, Zhengzhou, 450001, Henan, China
| | - Jingjing Liu
- Henan Institute of Medical and Pharmaceutical Sciences, Academy of Medical Science, Zhengzhou University, Zhengzhou, 450052, Henan, China; BGI College & Henan Institute of Medical and Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, 450052, Henan, China
| | - Liping Dai
- Henan Institute of Medical and Pharmaceutical Sciences, Academy of Medical Science, Zhengzhou University, Zhengzhou, 450052, Henan, China; BGI College & Henan Institute of Medical and Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, 450052, Henan, China
| | - Liguo Zhang
- Henan Institute of Medical and Pharmaceutical Sciences, Academy of Medical Science, Zhengzhou University, Zhengzhou, 450052, Henan, China; BGI College & Henan Institute of Medical and Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, 450052, Henan, China
| | - Dandan Fan
- Henan Institute of Medical and Pharmaceutical Sciences, Academy of Medical Science, Zhengzhou University, Zhengzhou, 450052, Henan, China; BGI College & Henan Institute of Medical and Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, 450052, Henan, China; Henan Key Laboratory for Pharmacology of Liver Diseases, Zhengzhou, 450052, Henan, China.
| | - Zhenyu Ji
- Henan Institute of Medical and Pharmaceutical Sciences, Academy of Medical Science, Zhengzhou University, Zhengzhou, 450052, Henan, China; BGI College & Henan Institute of Medical and Pharmaceutical Sciences, Zhengzhou University, Zhengzhou, 450052, Henan, China; Henan Key Laboratory for Pharmacology of Liver Diseases, Zhengzhou, 450052, Henan, China.
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Bustad HJ, Kallio JP, Vorland M, Fiorentino V, Sandberg S, Schmitt C, Aarsand AK, Martinez A. Acute Intermittent Porphyria: An Overview of Therapy Developments and Future Perspectives Focusing on Stabilisation of HMBS and Proteostasis Regulators. Int J Mol Sci 2021; 22:E675. [PMID: 33445488 PMCID: PMC7827610 DOI: 10.3390/ijms22020675] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2020] [Revised: 01/02/2021] [Accepted: 01/04/2021] [Indexed: 12/21/2022] Open
Abstract
Acute intermittent porphyria (AIP) is an autosomal dominant inherited disease with low clinical penetrance, caused by mutations in the hydroxymethylbilane synthase (HMBS) gene, which encodes the third enzyme in the haem biosynthesis pathway. In susceptible HMBS mutation carriers, triggering factors such as hormonal changes and commonly used drugs induce an overproduction and accumulation of toxic haem precursors in the liver. Clinically, this presents as acute attacks characterised by severe abdominal pain and a wide array of neurological and psychiatric symptoms, and, in the long-term setting, the development of primary liver cancer, hypertension and kidney failure. Treatment options are few, and therapies preventing the development of symptomatic disease and long-term complications are non-existent. Here, we provide an overview of the disorder and treatments already in use in clinical practice, in addition to other therapies under development or in the pipeline. We also introduce the pathomechanistic effects of HMBS mutations, and present and discuss emerging therapeutic options based on HMBS stabilisation and the regulation of proteostasis. These are novel mechanistic therapeutic approaches with the potential of prophylactic correction of the disease by totally or partially recovering the enzyme functionality. The present scenario appears promising for upcoming patient-tailored interventions in AIP.
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Affiliation(s)
- Helene J. Bustad
- Department of Biomedicine, University of Bergen, 5020 Bergen, Norway; (H.J.B.); (J.P.K.)
| | - Juha P. Kallio
- Department of Biomedicine, University of Bergen, 5020 Bergen, Norway; (H.J.B.); (J.P.K.)
| | - Marta Vorland
- Norwegian Porphyria Centre (NAPOS), Department for Medical Biochemistry and Pharmacology, Haukeland University Hospital, 5021 Bergen, Norway; (M.V.); (S.S.)
| | - Valeria Fiorentino
- INSERM U1149, Center for Research on Inflammation (CRI), Université de Paris, 75018 Paris, France; (V.F.); (C.S.)
| | - Sverre Sandberg
- Norwegian Porphyria Centre (NAPOS), Department for Medical Biochemistry and Pharmacology, Haukeland University Hospital, 5021 Bergen, Norway; (M.V.); (S.S.)
- Norwegian Organization for Quality Improvement of Laboratory Examinations (Noklus), Haraldsplass Deaconess Hospital, 5009 Bergen, Norway
| | - Caroline Schmitt
- INSERM U1149, Center for Research on Inflammation (CRI), Université de Paris, 75018 Paris, France; (V.F.); (C.S.)
- Assistance Publique Hôpitaux de Paris (AP-HP), Centre Français des Porphyries, Hôpital Louis Mourier, 92700 Colombes, France
| | - Aasne K. Aarsand
- Norwegian Porphyria Centre (NAPOS), Department for Medical Biochemistry and Pharmacology, Haukeland University Hospital, 5021 Bergen, Norway; (M.V.); (S.S.)
- Norwegian Organization for Quality Improvement of Laboratory Examinations (Noklus), Haraldsplass Deaconess Hospital, 5009 Bergen, Norway
| | - Aurora Martinez
- Department of Biomedicine, University of Bergen, 5020 Bergen, Norway; (H.J.B.); (J.P.K.)
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Zafar S, Jabeen I. Molecular Dynamic Simulations to Probe Stereoselectivity of Tiagabine Binding with Human GAT1. Molecules 2020; 25:molecules25204745. [PMID: 33081136 PMCID: PMC7587590 DOI: 10.3390/molecules25204745] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 10/08/2020] [Accepted: 10/12/2020] [Indexed: 12/11/2022] Open
Abstract
The human gamma aminobutyric acid transporter subtype 1 (hGAT1) located in the nerve terminals is known to catalyze the neuronal function by the electrogenic reuptake of γ-aminobutyric acid (GABA) with the co-transport of Na+ and Cl− ions. In the past, there has been a major research drive focused on the dysfunction of hGAT1 in several neurological disorders. Thus, hGAT1 of the GABAergic system has been well established as an attractive target for such diseased conditions. Till date, there are various reports about stereo selectivity of –COOH group of tiagabine, a Food and Drug Administration (FDA)-approved hGAT1-selective antiepileptic drug. However, the effect of the stereochemistry of the protonated –NH group of tiagabine has never been scrutinized. Therefore, in this study, tiagabine has been used to explore the binding hypothesis of different enantiomers of tiagabine. In addition, the impact of axial and equatorial configuration of the–COOH group attached at the meta position of the piperidine ring of tiagabine enantiomers was also investigated. Further, the stability of the finally selected four hGAT1–tiagabine enantiomers namely entries 3, 4, 6, and 9 was evaluated through 100 ns molecular dynamics (MD) simulations for the selection of the best probable tiagabine enantiomer. The results indicate that the protonated –NH group in the R-conformation and the –COOH group of Tiagabine in the equatorial configuration of entry 4 provide maximum strength in terms of interaction within the hGAT1 binding pocket to prevent the change in hGAT1 conformational state, i.e., from open-to-out to open-to-in as compared to other selected tiagabine enantiomers 3, 6, and 9.
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10
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Sharma A, Vincent L. Actinic keratosis area and severity index is not correlated with photodynamic therapy procedural pain. Photodiagnosis Photodyn Ther 2020; 31:101946. [PMID: 32795507 DOI: 10.1016/j.pdpdt.2020.101946] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 07/20/2020] [Accepted: 07/31/2020] [Indexed: 11/19/2022]
Abstract
BACKGROUND The Actinic Keratosis Area and Severity Index (AKASI) is a validated quantitative tool used to measure the severity of actinic keratoses. Given the success of AKASI in measuring outcomes and therapies related to actinic damage, we hypothesized that AKASI would be correlated to photodynamic therapy (PDT)-related pain. The aim of this study was to evaluate AKASI's correlation with PDT-associated pain for patients with AKs being treated with 5-Aminolevulinic acid (ALA) PDT. METHODS Thirty consecutive patients being treated for AKs with ALA PDT on the face and/or scalp were recruited from a single center. The AKASI of the treated areas were collected. The patient underwent a standard treatment with ALA-PDT for a total of 10 J/cm2 to treated area. Immediate post-procedural pain scores were measured using a visual-analog pain scale. Pain and AKASI scores were analyzed using Pearson's correlation coefficient. RESULTS AKASI was not correlated to pain score (Pearson correlation coefficient was 0.027, p = 0.87). In sub-group analyses, there was no strong correlation between the scalp AKASI or face AKASI and respective pain scores (p = 0.59 and p = 0.38, respectively). Furthermore, there was no strong correlation between the individual components of AKASI and pain score: distribution (p = 0.26), erythema (p = 0.66) and thickness (p = 0.43). CONCLUSION There is no correlation between the AKASI score and perceived pain from PDT. Therefore, the need for pain relief using a fan and evaporative cooling should be anticipated for all patients. We feel that this negative result is noteworthy as it supports mechanisms outside of AK destruction as the cause of immediate PDT-related pain.
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Uptake Transporters of the SLC21, SLC22A, and SLC15A Families in Anticancer Therapy-Modulators of Cellular Entry or Pharmacokinetics? Cancers (Basel) 2020; 12:cancers12082263. [PMID: 32806706 PMCID: PMC7464370 DOI: 10.3390/cancers12082263] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 07/16/2020] [Accepted: 07/21/2020] [Indexed: 12/21/2022] Open
Abstract
Solute carrier transporters comprise a large family of uptake transporters involved in the transmembrane transport of a wide array of endogenous substrates such as hormones, nutrients, and metabolites as well as of clinically important drugs. Several cancer therapeutics, ranging from chemotherapeutics such as topoisomerase inhibitors, DNA-intercalating drugs, and microtubule binders to targeted therapeutics such as tyrosine kinase inhibitors are substrates of solute carrier (SLC) transporters. Given that SLC transporters are expressed both in organs pivotal to drug absorption, distribution, metabolism, and elimination and in tumors, these transporters constitute determinants of cellular drug accumulation influencing intracellular drug concentration required for efficacy of the cancer treatment in tumor cells. In this review, we explore the current understanding of members of three SLC families, namely SLC21 (organic anion transporting polypeptides, OATPs), SLC22A (organic cation transporters, OCTs; organic cation/carnitine transporters, OCTNs; and organic anion transporters OATs), and SLC15A (peptide transporters, PEPTs) in the etiology of cancer, in transport of chemotherapeutic drugs, and their influence on efficacy or toxicity of pharmacotherapy. We further explore the idea to exploit the function of SLC transporters to enhance cancer cell accumulation of chemotherapeutics, which would be expected to reduce toxic side effects in healthy tissue and to improve efficacy.
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12
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Wu RWK, Chu ESM, Yow CMN. Evaluation of the effect of 5-aminolevulinic acid hexyl ester (H-ALA) PDT on EBV LMP1 protein expression in human nasopharyngeal cells. Photodiagnosis Photodyn Ther 2020; 30:101801. [PMID: 32360854 DOI: 10.1016/j.pdpdt.2020.101801] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Revised: 04/21/2020] [Accepted: 04/24/2020] [Indexed: 01/10/2023]
Abstract
Nasopharyngeal carcinoma (NPC) is of high prevalence in Hong Kong and southern China. The pathogenesis of NPC is closely associated with Epstein-Barr virus (EBV) infection via regulation of viral oncoprotein latent membrane protein 1 (LMP1). The conventional treatment for NPC is chemo-radiotherapy, but the prognosis remains poor for advanced stage, recurrent and metastatic NPC. Photodynamic therapy (PDT) is a therapeutic approach to combat tumors. PDT effectiveness depends on the interaction of photosensitizers, light and molecular oxygen. 5- aminolevulinic acid hexyl derivative (H-ALA) is one of the photosensitizers derived from 5-ALA. H-ALA with improved lipophilic properties by adding a long lipophilic chain (hexyl group) to 5-ALA, resulted in better penetration into cell cytoplasm. In this study, the effect of H-ALA-PDT on NPC cells (EBV positive C666-1 and EBV negative CNE2) was investigated. The H-ALA mediated cellular uptake and cytotoxicity was revealed via flow cytometry analysis and MTT assay respectively. H-ALA PDT mediated protein modulation was analysed by western blot analysis. Our finding reported that the cellular uptake of H-ALA in C666-1 and CNE2 cells was in a time dependent manner. H-ALA PDT was effective to C666-1 and CNE2 cells. EBV LMP1 proteins was expressed in C666-1 cells only and its expression was responsive to H-ALA PDT in a dose dependent manner. This work revealed the potential of H-ALA PDT as a treatment regiment for EBV positive NPC cells. Understanding the mechanism of H-ALA mediated PDT could develop improved strategies for the treatment of NPC.
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Affiliation(s)
- R W K Wu
- School of Medical and Health Sciences, Tung Wah College, Hong Kong Special Administrative Region; Medical Laboratory Science, Department of Health Technology & Informatics, Hong Kong Polytechnic University, Hong Kong Special Administrative Region.
| | - E S M Chu
- School of Medical and Health Sciences, Tung Wah College, Hong Kong Special Administrative Region
| | - C M N Yow
- Medical Laboratory Science, Department of Health Technology & Informatics, Hong Kong Polytechnic University, Hong Kong Special Administrative Region
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13
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Łątka K, Jończyk J, Bajda M. Structure modeling of γ-aminobutyric acid transporters - Molecular basics of ligand selectivity. Int J Biol Macromol 2020; 158:S0141-8130(20)33135-4. [PMID: 32376252 DOI: 10.1016/j.ijbiomac.2020.04.263] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 04/28/2020] [Accepted: 04/29/2020] [Indexed: 11/15/2022]
Abstract
γ-Aminobutyric acid transporters are responsible for regulating the GABA level in the synaptic cleft. In this way, they affect GABA-ergic transmission which is important for the proper functioning of the central nervous system. The exact structure of GABA transporters is still unknown, which hinders the design of new, potent and selective inhibitors. For these reasons, we decided to create models of all types of human gamma-aminobutyric acid transporters. They were built based on crystal structures of related proteins from the SLC6 family using homology modeling methods. The reliability of the received models has been confirmed by a number of tools assessing the quality of protein models. To determine the ligand binding mode and indicate the amino acids responsible for selectivity, docking studies and molecular dynamics simulations were performed. The amino acids lining the bottom of the main binding site have a major impact on the selective ligand binding. In addition, an important element is the non-helical fragment of the transmembrane domain 10, and several amino acids within the vestibule of the transporters, which affect its volume. To check whether obtained models are suitable to distinguish active compounds from inactive ones, enrichment plots were prepared. Results suggest that our models may be useful in the search for new inhibitors of GABA transporters of the desired selectivity.
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Affiliation(s)
- Kamil Łątka
- Jagiellonian University Medical College, Faculty of Pharmacy, Department of Physicochemical Drug Analysis, 30-688 Cracow, Medyczna 9, Poland
| | - Jakub Jończyk
- Jagiellonian University Medical College, Faculty of Pharmacy, Department of Physicochemical Drug Analysis, 30-688 Cracow, Medyczna 9, Poland
| | - Marek Bajda
- Jagiellonian University Medical College, Faculty of Pharmacy, Department of Physicochemical Drug Analysis, 30-688 Cracow, Medyczna 9, Poland.
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14
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de Oliveira ER, Inada NM, Blanco KC, Bagnato VS, Salvio AG. Field cancerization treatment using topical photodynamic therapy: A comparison between two aminolevulinate derivatives. Photodiagnosis Photodyn Ther 2019; 30:101603. [PMID: 31821900 DOI: 10.1016/j.pdpdt.2019.101603] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 11/13/2019] [Accepted: 11/15/2019] [Indexed: 01/10/2023]
Abstract
The objective of this study was to evaluate and compare the clinical response to PDT (Photodynamic Therapy) in field cancerization using two aminolevulinate derivatives. Forty patients with multiple actinic keratosis (AK) on forearms and hands scattered received two sessions of ALA and MAL-PDT at 630 nm (36 J/cm2). The AK clearance rate was 72 % for both drugs with a significant decrease in AK observed clinically (p < 00,001). Clinical improvement in field cancerization using two aminolevulinate derivatives in PDT is proven with no significant difference in the efficacy of drugs.
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Affiliation(s)
| | - Natalia M Inada
- São Carlos Institute of Physics, University of São Paulo, São Carlos, SP, Brazil
| | - Kate Cristina Blanco
- São Carlos Institute of Physics, University of São Paulo, São Carlos, SP, Brazil.
| | - Vanderlei S Bagnato
- São Carlos Institute of Physics, University of São Paulo, São Carlos, SP, Brazil
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Kickinger S, Hellsberg E, Frølund B, Schousboe A, Ecker GF, Wellendorph P. Structural and molecular aspects of betaine-GABA transporter 1 (BGT1) and its relation to brain function. Neuropharmacology 2019; 161:107644. [PMID: 31108110 DOI: 10.1016/j.neuropharm.2019.05.021] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Revised: 04/14/2019] [Accepted: 05/16/2019] [Indexed: 01/09/2023]
Abstract
ɣ-aminobutyric-acid (GABA) functions as the principal inhibitory neurotransmitter in the central nervous system. Imbalances in GABAergic neurotransmission are involved in the pathophysiology of various neurological diseases such as epilepsy, Alzheimer's disease and stroke. GABA transporters (GATs) facilitate the termination of GABAergic signaling by transporting GABA together with sodium and chloride from the synaptic cleft into presynaptic neurons and surrounding glial cells. Four different GATs have been identified that all belong to the solute carrier 6 (SLC6) transporter family: GAT1-3 (SLC6A1, SLC6A13, SLC6A11) and betaine/GABA transporter 1 (BGT1, SLC6A12). BGT1 has emerged as an interesting target for treating epilepsy due to animal studies that reported anticonvulsant effects for the GAT1/BGT1 selective inhibitor EF1502 and the BGT1 selective inhibitor RPC-425. However, the precise involvement of BGT1 in epilepsy remains elusive because of its controversial expression levels in the brain and the lack of highly selective and potent tool compounds. This review gathers the current structural and functional knowledge on BGT1 with emphasis on brain relevance, discusses all available compounds, and tries to shed light on the molecular determinants driving BGT1 selectivity. This article is part of the issue entitled 'Special Issue on Neurotransmitter Transporters'.
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Affiliation(s)
- Stefanie Kickinger
- University of Vienna, Department of Pharmaceutical Chemistry, Althanstrasse 14, 1090, Vienna, Austria
| | - Eva Hellsberg
- University of Vienna, Department of Pharmaceutical Chemistry, Althanstrasse 14, 1090, Vienna, Austria
| | - Bente Frølund
- University of Copenhagen, Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, 2 Universitetsparken, 2100, Copenhagen, Denmark
| | - Arne Schousboe
- University of Copenhagen, Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, 2 Universitetsparken, 2100, Copenhagen, Denmark
| | - Gerhard F Ecker
- University of Vienna, Department of Pharmaceutical Chemistry, Althanstrasse 14, 1090, Vienna, Austria
| | - Petrine Wellendorph
- University of Copenhagen, Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, 2 Universitetsparken, 2100, Copenhagen, Denmark.
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16
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Héja L, Simon Á, Szabó Z, Kardos J. Feedback adaptation of synaptic excitability via Glu:Na + symport driven astrocytic GABA and Gln release. Neuropharmacology 2019; 161:107629. [PMID: 31103619 DOI: 10.1016/j.neuropharm.2019.05.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 03/30/2019] [Accepted: 05/07/2019] [Indexed: 02/08/2023]
Abstract
Glutamatergic transmission composed of the arriving of action potential at the axon terminal, fast vesicular Glu release, postsynaptic Glu receptor activation, astrocytic Glu clearance and Glu→Gln shuttle is an abundantly investigated phenomenon. Despite its essential role, however, much less is known about the consequences of the mechanistic connotations of Glu:Na+ symport. Due to the coupled Na+ transport, Glu uptake results in significantly elevated intracellular astrocytic [Na+] that markedly alters the driving force of other Na+-coupled astrocytic transporters. The resulting GABA and Gln release by reverse transport through the respective GAT-3 and SNAT3 transporters help to re-establish the physiological Na+ homeostasis without ATP dissipation and consequently leads to enhanced tonic inhibition and replenishment of axonal glutamate pool. Here, we place this emerging astrocytic adjustment of synaptic excitability into the centre of future perspectives. This article is part of the issue entitled 'Special Issue on Neurotransmitter Transporters'.
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Affiliation(s)
- László Héja
- Functional Pharmacology Research Group, Institute of Organic Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudósok körútja 2, 1117, Budapest, Hungary
| | - Ágnes Simon
- Functional Pharmacology Research Group, Institute of Organic Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudósok körútja 2, 1117, Budapest, Hungary
| | - Zsolt Szabó
- Functional Pharmacology Research Group, Institute of Organic Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudósok körútja 2, 1117, Budapest, Hungary
| | - Julianna Kardos
- Functional Pharmacology Research Group, Institute of Organic Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar tudósok körútja 2, 1117, Budapest, Hungary.
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Zafar S, Jabeen I. GRID-independent molecular descriptor analysis and molecular docking studies to mimic the binding hypothesis of γ-aminobutyric acid transporter 1 (GAT1) inhibitors. PeerJ 2019; 7:e6283. [PMID: 30723616 PMCID: PMC6360079 DOI: 10.7717/peerj.6283] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Accepted: 12/14/2018] [Indexed: 12/13/2022] Open
Abstract
Background The γ-aminobutyric acid (GABA) transporter GAT1 is involved in GABA transport across the biological membrane in and out of the synaptic cleft. The efficiency of this Na+ coupled GABA transport is regulated by an electrochemical gradient, which is directed inward under normal conditions. However, in certain pathophysiological situations, including strong depolarization or an imbalance in ion homeostasis, the GABA influx into the cytoplasm is increased by re-uptake transport mechanism. This mechanism may lead to extra removal of extracellular GABA which results in numerous neurological disorders such as epilepsy. Thus, small molecule inhibitors of GABA re-uptake may enhance GABA activity at the synaptic clefts. Methods In the present study, various GRID-independent molecular descriptor (GRIND) models have been developed to shed light on the 3D structural features of human GAT1 (hGAT1) inhibitors using nipecotic acid and N-diarylalkenyl piperidine analogs. Further, a binding hypothesis has been developed for the selected GAT1 antagonists by molecular docking inside the binding cavity of hGAT1 homology model. Results Our results indicate that two hydrogen bond acceptors, one hydrogen bond donor and one hydrophobic region at certain distances from each other play an important role in achieving high inhibitory potency against hGAT1. Our docking results elucidate the importance of the COOH group in hGAT1 antagonists by considering substitution of the COOH group with an isoxazol ring in compound 37, which subsequently leads to a three order of magnitude decrease in biological activity of 37 (IC50 = 38 µM) as compared to compound 1 (IC50 = 0.040 µM). Discussion Our docking results are strengthened by the structure activity relationship of the data series as well as by GRIND models, thus providing a significant structural basis for understanding the binding of antagonists, which may be useful for guiding the design of hGAT1 inhibitors.
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Affiliation(s)
- Sadia Zafar
- Research Center for Modeling and Simulation (RCMS), National University of Sciences and Technology (NUST), Islamabad, Federal, Pakistan
| | - Ishrat Jabeen
- Research Center for Modeling and Simulation (RCMS), National University of Sciences and Technology (NUST), Islamabad, Federal, Pakistan
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18
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Zafar S, Nguyen ME, Muthyala R, Jabeen I, Sham YY. Modeling and Simulation of hGAT1: A Mechanistic Investigation of the GABA Transport Process. Comput Struct Biotechnol J 2018; 17:61-69. [PMID: 30619541 PMCID: PMC6312766 DOI: 10.1016/j.csbj.2018.12.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Revised: 12/06/2018] [Accepted: 12/09/2018] [Indexed: 01/30/2023] Open
Abstract
Human γ-Aminobutyric acid transporter 1 (hGAT1) is a Na+/Cl- dependent co-transporter that plays a key role in the inhibitory neurotransmission of GABA in the brain. Due to the lack of structural data, the exact co-transport mechanism of GABA reuptake by hGAT1 remains unclear. To examine the roles of the co-transport ions and the nature of their interactions with GABA, homology modeling and molecular dynamics simulations of the hGAT1 in the open-to-out conformation were carried out. Our study focused on the sequential preloading of Na+ and Cl- ions, followed by GABA binding. Our simulations showed pre-loading of ions maintains the transport ready state of hGAT1 in the open-to-out conformation essential for GABA binding. Of the four putative preloaded states, GABA binding to the fully loaded state is most favored. Binding of Na+ ion to the Na1 site helps to maintain the open-to-out conformation for GABA binding as compared to the Na2 site. GABA binding to the mono-sodium or the di-sodium loaded states leads to destabilization of Na+ ions within their binding sites. The two most prominent interactions required for GABA binding include interaction between carboxylate group of GABA with the bound Na+ ion in Na1 binding site and the hydroxyl group of Y140. Overall our results support the fully loaded state as the predominate state for GABA binding. Our study further illustrates that Na+ ion within the Na1 site is crucial for GABA recognition. Therefore, a revised mechanism is proposed for the initial step of hGAT1 translocation cycle.
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Affiliation(s)
- Sadia Zafar
- Research Center for Modeling and Simulation (RCMS), National University of Sciences and Technology (NUST), Islamabad, Pakistan
| | - Megin E. Nguyen
- Bioinformatics and Computational Biology Program, University of Minnesota, United States
| | - Ramaiah Muthyala
- Department of Experimental and Clinical Pharmacology & Center for Orphan Drug Research, College of Pharmacy, University of Minnesota, Minneapolis, MN 55455, United States
| | - Ishrat Jabeen
- Research Center for Modeling and Simulation (RCMS), National University of Sciences and Technology (NUST), Islamabad, Pakistan
| | - Yuk Y. Sham
- Department of Integrative Biology and Physiology, Medical School, University of Minnesota, Minneapolis, MN 55455, United States
- Bioinformatics and Computational Biology Program, University of Minnesota, United States
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19
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Zafar S, Jabeen I. Structure, Function, and Modulation of γ-Aminobutyric Acid Transporter 1 (GAT1) in Neurological Disorders: A Pharmacoinformatic Prospective. Front Chem 2018; 6:397. [PMID: 30255012 PMCID: PMC6141625 DOI: 10.3389/fchem.2018.00397] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Accepted: 08/20/2018] [Indexed: 02/03/2023] Open
Abstract
γ-Aminobutyric acid (GABA) Transporters (GATs) belong to sodium and chloride dependent-transporter family and are widely expressed throughout the brain. Notably, GAT1 is accountable for sustaining 75% of the synaptic GABA concentration and entails its transport to the GABAA receptors to initiate the receptor-mediated inhibition of post-synaptic neurons. Imbalance in ion homeostasis has been associated with several neurological disorders related to the GABAergic system. However, inhibition of the GABA uptake by these transporters has been accepted as an effective approach to enhance GABAergic inhibitory neurotransmission in the treatment of seizures in epileptic and other neurological disorders. Here, we reviewed computational methodologies including molecular modeling, docking, and molecular dynamic simulations studies to underscore the structure and function of GAT1 in the GABAergic system. Additionally, various SAR and QSAR methodologies have been reviewed to probe the 3D structural features of inhibitors required to modulate GATs activity. Overall, present review provides an overview of crucial role of GAT1 in GABAergic system and its modulation to evade neurological disorders.
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Affiliation(s)
| | - Ishrat Jabeen
- Research Center for Modeling and Simulation, National University of Sciences and Technology, Islamabad, Pakistan
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20
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Ning S, Kang Q, Fan D, Liu J, Xue C, Zhang X, Ding C, Zhang J, Peng Q, Ji Z. Protein 4.1R is Involved in the Transport of 5-Aminolevulinic Acid by Interaction with GATs in MEF Cells. Photochem Photobiol 2017; 94:173-178. [DOI: 10.1111/php.12842] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2017] [Accepted: 08/30/2017] [Indexed: 11/28/2022]
Affiliation(s)
- Shuwei Ning
- Institute of Medical and Pharmaceutical Sciences; Zhengzhou University; Zhengzhou China
- School of Life Sciences; Zhengzhou University; Zhengzhou China
| | - Qiaozhen Kang
- School of Life Sciences; Zhengzhou University; Zhengzhou China
| | - Dandan Fan
- Institute of Medical and Pharmaceutical Sciences; Zhengzhou University; Zhengzhou China
| | - Jingjing Liu
- Institute of Medical and Pharmaceutical Sciences; Zhengzhou University; Zhengzhou China
| | - Chaoyue Xue
- Institute of Medical and Pharmaceutical Sciences; Zhengzhou University; Zhengzhou China
- School of Life Sciences; Zhengzhou University; Zhengzhou China
| | - Xiaolin Zhang
- Institute of Medical and Pharmaceutical Sciences; Zhengzhou University; Zhengzhou China
- School of Life Sciences; Zhengzhou University; Zhengzhou China
| | - Cong Ding
- School of Life Sciences; Zhengzhou University; Zhengzhou China
| | - Jianying Zhang
- Institute of Medical and Pharmaceutical Sciences; Zhengzhou University; Zhengzhou China
| | - Qian Peng
- Department of Pathology; The Norwegian Radium Hospital; Oslo University Hospital; University of Oslo; Montebello Oslo Norway
| | - Zhenyu Ji
- Institute of Medical and Pharmaceutical Sciences; Zhengzhou University; Zhengzhou China
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21
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Damgaard M, Haugaard AS, Kickinger S, Al-Khawaja A, Lie MEK, Ecker GF, Clausen RP, Frølund B. Development of Non-GAT1-Selective Inhibitors: Challenges and Achievements. ADVANCES IN NEUROBIOLOGY 2017; 16:315-332. [DOI: 10.1007/978-3-319-55769-4_16] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/08/2023]
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22
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Harmatys KM, Musso AJ, Clear KJ, Smith BD. Small molecule additive enhances cell uptake of 5-aminolevulinic acid and conversion to protoporphyrin IX. Photochem Photobiol Sci 2016; 15:1408-1416. [PMID: 27722428 PMCID: PMC5093051 DOI: 10.1039/c6pp00151c] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Accepted: 10/04/2016] [Indexed: 12/20/2022]
Abstract
Administration of exogenous 5-aminolevulinic acid (5-ALA) to cancerous tissue leads to intracellular production of photoactive protoporphyrin IX, a biosynthetic process that enables photodynamic therapy and fluorescence-guided surgery of cancer. Cell uptake of 5-ALA is limited by its polar structure and there is a need for non-toxic chemical additives that can enhance its cell permeation. Two zinc-bis(dipicolylamine) (ZnBDPA) compounds were evaluated for their ability to promote uptake of 5-ALA into Chinese Hamster Ovary (CHO-K1) cells and produce protoporphyrin IX. One of the ZnBDPA compounds was found to be quite effective, and a systematic comparison of cells incubated with 5-ALA (100 μM) for 6 hours showed that the presence of this ZnBDPA compound (10 μM) produced 3-fold more protoporphyrin IX than cells treated with 5-ALA alone. The results of mechanistic studies suggest that the ZnBDPA compound does not interact strongly with the 5-ALA. Rather, the additive is membrane active and transiently disrupts the cell membrane, permitting 5-ALA permeation. The membrane disruption is not severe enough to induce cell toxicity or allow passage of larger macromolecules like plasmid DNA.
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Affiliation(s)
- Kara M Harmatys
- Department of Chemistry and Biochemistry, 236 Nieuwland Science Hall, University of Notre Dame, Notre Dame, IN 46556, USA.
| | - Anthony J Musso
- Department of Chemistry and Biochemistry, 236 Nieuwland Science Hall, University of Notre Dame, Notre Dame, IN 46556, USA.
| | - Kasey J Clear
- Department of Chemistry and Biochemistry, 236 Nieuwland Science Hall, University of Notre Dame, Notre Dame, IN 46556, USA.
| | - Bradley D Smith
- Department of Chemistry and Biochemistry, 236 Nieuwland Science Hall, University of Notre Dame, Notre Dame, IN 46556, USA.
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23
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Talevi A. Computational approaches for innovative antiepileptic drug discovery. Expert Opin Drug Discov 2016; 11:1001-16. [DOI: 10.1080/17460441.2016.1216965] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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24
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Singh S, Vijaya Prabhu S, Suryanarayanan V, Bhardwaj R, Singh SK, Dubey VK. Molecular docking and structure-based virtual screening studies of potential drug target, CAAX prenyl proteases, of Leishmania donovani. J Biomol Struct Dyn 2016; 34:2367-86. [PMID: 26551589 DOI: 10.1080/07391102.2015.1116411] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Targeting CAAX prenyl proteases of Leishmania donovani can be a good approach towards developing a drug molecule against Leishmaniasis. We have modeled the structure of CAAX prenyl protease I and II of L. donovani, using homology modeling approach. The structures were further validated using Ramachandran plot and ProSA. Active site prediction has shown difference in the amino acid residues present at the active site of CAAX prenyl protease I and CAAX prenyl protease II. The electrostatic potential surface of the CAAX prenyl protease I and II has revealed that CAAX prenyl protease I has more electropositive and electronegative potentials as compared CAAX prenyl protease II suggesting significant difference in their activity. Molecular docking with known bisubstrate analog inhibitors of protein farnesyl transferase and peptidyl (acyloxy) methyl ketones reveals significant binding of these molecules with CAAX prenyl protease I, but comparatively less binding with CAAX prenyl protease II. New and potent inhibitors were also found using structure-based virtual screening. The best docked compounds obtained from virtual screening were subjected to induced fit docking to get best docked configurations. Prediction of drug-like characteristics has revealed that the best docked compounds are in line with Lipinski's rule. Moreover, best docked protein-ligand complexes of CAAX prenyl protease I and II are found to be stable throughout 20 ns simulation. Overall, the study has identified potent drug molecules targeting CAAX prenyl protease I and II of L. donovani whose drug candidature can be verified further using biochemical and cellular studies.
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Affiliation(s)
- Shalini Singh
- a Department of Biosciences and Bioengineering , Indian Institute of Technology Guwahati , Guwahati , Assam 781039 , India
| | - Sitrarasu Vijaya Prabhu
- b Computer Aided Drug Designing and Molecular Modeling Laboratory, Department of Bioinformatics , Alagappa University , Karaikudi , Tamil Nadu 630004 , India
| | - Venkatesan Suryanarayanan
- b Computer Aided Drug Designing and Molecular Modeling Laboratory, Department of Bioinformatics , Alagappa University , Karaikudi , Tamil Nadu 630004 , India
| | - Ruchika Bhardwaj
- a Department of Biosciences and Bioengineering , Indian Institute of Technology Guwahati , Guwahati , Assam 781039 , India
| | - Sanjeev Kumar Singh
- b Computer Aided Drug Designing and Molecular Modeling Laboratory, Department of Bioinformatics , Alagappa University , Karaikudi , Tamil Nadu 630004 , India
| | - Vikash Kumar Dubey
- a Department of Biosciences and Bioengineering , Indian Institute of Technology Guwahati , Guwahati , Assam 781039 , India
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Helander L, Sharma A, Krokan HE, Plaetzer K, Krammer B, Tortik N, Gederaas OA, Slupphaug G, Hagen L. Photodynamic treatment with hexyl-aminolevulinate mediates reversible thiol oxidation in core oxidative stress signaling proteins. MOLECULAR BIOSYSTEMS 2016; 12:796-805. [DOI: 10.1039/c5mb00744e] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
HAL-PDT mediates reversible cysteine oxidation in core proteins involved in oxidative stress and apoptotic signalling.
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Affiliation(s)
- Linda Helander
- Department of Cancer Research and Molecular Medicine
- Norwegian University of Science and Technology
- Norway
| | - Animesh Sharma
- Department of Cancer Research and Molecular Medicine
- Norwegian University of Science and Technology
- Norway
- PROMEC Core Facility for Proteomics and Metabolomics
- Norwegian University of Science and Technology
| | - Hans E. Krokan
- Department of Cancer Research and Molecular Medicine
- Norwegian University of Science and Technology
- Norway
| | - Kristjan Plaetzer
- Laboratory of Photodynamic Inactivation of Microorganisms
- Department of Materials Science and Physics
- University of Salzburg
- Austria
| | - Barbara Krammer
- Division of Molecular Tumor Biology
- Department of Molecular Biology
- University of Salzburg
- Austria
| | - Nicole Tortik
- Laboratory of Photodynamic Inactivation of Microorganisms
- Department of Materials Science and Physics
- University of Salzburg
- Austria
| | - Odrun A. Gederaas
- Department of Cancer Research and Molecular Medicine
- Norwegian University of Science and Technology
- Norway
| | - Geir Slupphaug
- Department of Cancer Research and Molecular Medicine
- Norwegian University of Science and Technology
- Norway
- PROMEC Core Facility for Proteomics and Metabolomics
- Norwegian University of Science and Technology
| | - Lars Hagen
- Department of Cancer Research and Molecular Medicine
- Norwegian University of Science and Technology
- Norway
- PROMEC Core Facility for Proteomics and Metabolomics
- Norwegian University of Science and Technology
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26
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Jurik A, Zdrazil B, Holy M, Stockner T, Sitte HH, Ecker GF. A binding mode hypothesis of tiagabine confirms liothyronine effect on γ-aminobutyric acid transporter 1 (GAT1). J Med Chem 2015; 58:2149-58. [PMID: 25679268 PMCID: PMC4360375 DOI: 10.1021/jm5015428] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
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Elevating
GABA levels in the synaptic cleft by inhibiting its reuptake
carrier GAT1 is an established approach for the treatment of CNS disorders
like epilepsy. With the increasing availability of crystal structures
of transmembrane transporters, structure-based approaches to elucidate
the molecular basis of ligand–transporter interaction also
become feasible. Experimental data guided docking of derivatives of
the GAT1 inhibitor tiagabine into a protein homology model of GAT1
allowed derivation of a common binding mode for this class of inhibitors
that is able to account for the distinct structure–activity
relationship pattern of the data set. Translating essential binding
features into a pharmacophore model followed by in silico screening
of the DrugBank identified liothyronine as a drug potentially exerting
a similar effect on GAT1. Experimental testing further confirmed the
GAT1 inhibiting properties of this thyroid hormone.
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Affiliation(s)
- Andreas Jurik
- University of Vienna , Department of Pharmaceutical Chemistry, Division of Drug Design and Medicinal Chemistry, Althanstraße 14, 1090 Vienna, Austria
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27
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Kiesslich T, Helander L, Illig R, Oberdanner C, Wagner A, Lettner H, Jakab M, Plaetzer K. Real-time analysis of endogenous protoporphyrin IX fluorescence from δ-aminolevulinic acid and its derivatives reveals distinct time- and dose-dependent characteristics in vitro. JOURNAL OF BIOMEDICAL OPTICS 2014; 19:085007. [PMID: 25117078 DOI: 10.1117/1.jbo.19.8.085007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Accepted: 07/14/2014] [Indexed: 06/03/2023]
Abstract
Photodynamic therapy (PDT) and photodiagnosis based on the intracellular production of the photosensitizer protoporphyrin IX (PPIX) by administration of its metabolic precursor -aminolevulinic acid (ALA) achieved their breakthrough upon the clinical approval of MAL (ALA methyl ester) and HAL (ALA hexyl ester). For newly developed ALA derivatives or application in new tumor types, in vitro determination of PPIX formation involves multiparametric experiments covering variable pro-drug concentrations, medium composition, time points of analysis, and cell type(s). This study uses a fluorescence microplate reader with a built-in temperature and atmosphere control to investigate the high-resolution long-term kinetics (72 h) of cellular PPIX fueled by administration of either ALA, MAL, or HAL for each 10 different concentrations. For simultaneous proliferation correction, A431 cells were stably transfected with green fluorescent protein. The results indicate that the peak PPIX level is a function of both, incubation concentration and period: maximal PPIX is generated with 1 to 2-mM ALA/MAL or 0.125-mM HAL; also, the PPIX peak shifts to longer incubation periods with increasing pro-drug concentrations. The results underline the need for detailed temporal analysis of PPIX formation to optimize ALA (derivative)-based PDT or photodiagnosis and highlight the value of environment-controlled microplate readers for automated in vitro analysis.
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Affiliation(s)
- Tobias Kiesslich
- Paracelsus Medical University, Institute of Physiology and Pathophysiology, Strubergasse 21, Salzburg A-5020, AustriabParacelsus Medical University/Salzburger Landeskliniken, Department of Internal Medicine I, Muellner Hauptstrasse 48, Salzburg A-5020, Au
| | - Linda Helander
- Norwegian University of Science and Technology, Department of Cancer Research and Molecular Medicine, Erling Skjalgssons gate 1, N-7491 Trondheim, Norway
| | - Romana Illig
- Paracelsus Medical University/Salzburger Landeskliniken, Institute of Pathology, Muellner Hauptstrasse 48, Salzburg A-5020, Austria
| | | | - Andrej Wagner
- Paracelsus Medical University/Salzburger Landeskliniken, Department of Internal Medicine I, Muellner Hauptstrasse 48, Salzburg A-5020, Austria
| | - Herbert Lettner
- University of Salzburg, Department of Materials Science and Physics, Division of Physics and Biophysics, Hellbrunnerstraße 34, Salzburg A-5020, Austria
| | - Martin Jakab
- Paracelsus Medical University, Institute of Physiology and Pathophysiology, Strubergasse 21, Salzburg A-5020, Austria
| | - Kristjan Plaetzer
- University of Salzburg, Department of Materials Science and Physics, Laboratory of Photodynamic Inactivation of Microorganisms, Hellbrunnerstraße 34, Salzburg A-5020, Austria
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28
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Tran TT, Mu A, Adachi Y, Adachi Y, Taketani S. Neurotransmitter Transporter Family Including SLC6A6 and SLC6A13 Contributes to the 5-Aminolevulinic Acid (ALA)-Induced Accumulation of Protoporphyrin IX and Photodamage, through Uptake of ALA by Cancerous Cells. Photochem Photobiol 2014; 90:1136-43. [PMID: 24842606 DOI: 10.1111/php.12290] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2014] [Accepted: 05/14/2014] [Indexed: 01/08/2023]
Affiliation(s)
- Tai Tien Tran
- Department of Biotechnology; Kyoto Institute of Technology; Kyoto Japan
| | - Anfeng Mu
- Department of Biotechnology; Kyoto Institute of Technology; Kyoto Japan
| | - Yuka Adachi
- Department of Biotechnology; Kyoto Institute of Technology; Kyoto Japan
| | - Yasushi Adachi
- Department of Pathology; Toyooka Hospital; Toyooka Hyogo Japan
| | - Shigeru Taketani
- Department of Biotechnology; Kyoto Institute of Technology; Kyoto Japan
- Insect Biomedical Center; Kyoto Institute of Technology; Kyoto Japan
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