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Tarmoun K, Lachance V, Le Corvec V, Bélanger SM, Beaucaire G, Kourrich S. Comprehensive Analysis of Age- and Sex-Related Expression of the Chaperone Protein Sigma-1R in the Mouse Brain. Brain Sci 2024; 14:881. [PMID: 39335377 PMCID: PMC11430507 DOI: 10.3390/brainsci14090881] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2024] [Revised: 08/28/2024] [Accepted: 08/28/2024] [Indexed: 09/30/2024] Open
Abstract
Sigma-1R (S1R) is a ubiquitously distributed protein highly expressed in the brain and liver. It acts as a ligand-inducible chaperone protein localized at the endoplasmic reticulum. S1R participates in several signaling pathways that oversee diverse cellular and neurological functions, such as calcium and proteome homeostasis, neuronal activity, memory, and emotional regulation. Despite its crucial functions, S1R expression profile in the brain with respect to age and sex remains elusive. To shed light on this matter, we assessed S1R distribution in the mouse brain across different developmental stages, including juvenile, early adult, and middle-aged mice. Using immunohistochemistry, we found that S1R is predominantly expressed in the hippocampus in juvenile mice, particularly in CA1 and CA3 regions. Notably, S1R is not expressed in the subgranular layer of the dentate gyrus of juvenile mice. We observed dynamic changes in S1R levels during development, with most brain regions showing either an abrupt or gradual decline as mice transition from juveniles to adults. Sexual dimorphism is observed before puberty in the hippocampus and hypothalamus and during adulthood in the hippocampus and cortex.
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Affiliation(s)
- Khadija Tarmoun
- Department of Biological Sciences, Faculty of Sciences, University of Quebec at Montreal, 141 President-Kennedy Street, Montreal, QC H2X 1Y4, Canada
- Center of Excellence for Research on Orphan Diseases, Courtois Foundation (CERMO-FC), Montreal, QC H2X 3Y7, Canada
| | - Véronik Lachance
- Department of Biological Sciences, Faculty of Sciences, University of Quebec at Montreal, 141 President-Kennedy Street, Montreal, QC H2X 1Y4, Canada
- Center of Excellence for Research on Orphan Diseases, Courtois Foundation (CERMO-FC), Montreal, QC H2X 3Y7, Canada
| | - Victoria Le Corvec
- Department of Biological Sciences, Faculty of Sciences, University of Quebec at Montreal, 141 President-Kennedy Street, Montreal, QC H2X 1Y4, Canada
- Center of Excellence for Research on Orphan Diseases, Courtois Foundation (CERMO-FC), Montreal, QC H2X 3Y7, Canada
| | - Sara-Maude Bélanger
- Department of Biological Sciences, Faculty of Sciences, University of Quebec at Montreal, 141 President-Kennedy Street, Montreal, QC H2X 1Y4, Canada
- Center of Excellence for Research on Orphan Diseases, Courtois Foundation (CERMO-FC), Montreal, QC H2X 3Y7, Canada
| | - Guillaume Beaucaire
- Department of Biological Sciences, Faculty of Sciences, University of Quebec at Montreal, 141 President-Kennedy Street, Montreal, QC H2X 1Y4, Canada
- Center of Excellence for Research on Orphan Diseases, Courtois Foundation (CERMO-FC), Montreal, QC H2X 3Y7, Canada
| | - Saïd Kourrich
- Department of Biological Sciences, Faculty of Sciences, University of Quebec at Montreal, 141 President-Kennedy Street, Montreal, QC H2X 1Y4, Canada
- Center of Excellence for Research on Orphan Diseases, Courtois Foundation (CERMO-FC), Montreal, QC H2X 3Y7, Canada
- Center for Studies in Behavioral Neurobiology, Concordia University, Montreal, QC H4B 1R6, Canada
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2
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Kim M, Bezprozvanny I. Structure-Based Modeling of Sigma 1 Receptor Interactions with Ligands and Cholesterol and Implications for Its Biological Function. Int J Mol Sci 2023; 24:12980. [PMID: 37629160 PMCID: PMC10455549 DOI: 10.3390/ijms241612980] [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: 07/26/2023] [Revised: 08/15/2023] [Accepted: 08/17/2023] [Indexed: 08/27/2023] Open
Abstract
The sigma 1 receptor (S1R) is a 223-amino-acid-long transmembrane endoplasmic reticulum (ER) protein. The S1R plays an important role in neuronal health and it is an established therapeutic target for neurodegenerative and neuropsychiatric disorders. Despite its importance in physiology and disease, the biological function of S1R is poorly understood. To gain insight into the biological and signaling functions of S1R, we took advantage of recently reported crystal structures of human and Xenopus S1Rs and performed structural modeling of S1R interactions with ligands and cholesterol in the presence of the membrane. By combining bioinformatics analysis of S1R sequence and structural modelling approaches, we proposed a model that suggests that S1R may exist in two distinct conformations-"dynamic monomer" (DM) and "anchored monomer" (AM). We further propose that equilibrium between AM and DM conformations of S1R is essential for its biological function in cells, with AM conformation facilitating the oligomerization of S1R and DM conformation facilitating deoligomerization. Consistent with experimental evidence, our hypothesis predicts that increased levels of membrane cholesterol and S1R antagonists should promote the oligomeric state of S1R, but S1R agonists and pathogenic mutations should promote its deoligomerization. Obtained results provide mechanistic insights into signaling functions of S1R in cells, and the proposed model may help to explain neuroprotective effects of S1R modulators.
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Affiliation(s)
- Meewhi Kim
- Department of Physiology, UT Southwestern Medical Center at Dallas, Dallas, TX 75390, USA
| | - Ilya Bezprozvanny
- Department of Physiology, UT Southwestern Medical Center at Dallas, Dallas, TX 75390, USA
- Laboratory of Molecular Neurodegeneration, Peter the Great St Petersburg State Polytechnical University, 195251 St. Petersburg, Russia
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3
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Li J, Satyshur KA, Guo LW, Ruoho AE. Sphingoid Bases Regulate the Sigma-1 Receptor-Sphingosine and N, N'-Dimethylsphingosine Are Endogenous Agonists. Int J Mol Sci 2023; 24:3103. [PMID: 36834510 PMCID: PMC9962145 DOI: 10.3390/ijms24043103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 01/28/2023] [Accepted: 02/01/2023] [Indexed: 02/09/2023] Open
Abstract
Both bioactive sphingolipids and Sigma-1 receptor (S1R) chaperones occur ubiquitously in mammalian cell membranes. Endogenous compounds that regulate the S1R are important for controlling S1R responses to cellular stress. Herein, we interrogated the S1R in intact Retinal Pigment Epithelial cells (ARPE-19) with the bioactive sphingoid base, sphingosine (SPH), or the pain-provoking dimethylated SPH derivative, N,N'-dimethylsphingosine (DMS). As informed by a modified native gel approach, the basal and antagonist (BD-1047)-stabilized S1R oligomers dissociated to protomeric forms in the presence of SPH or DMS (PRE-084 as control). We, thus, posited that SPH and DMS are endogenous S1R agonists. Consistently, in silico docking of SPH and DMS to the S1R protomer showed strong associations with Asp126 and Glu172 in the cupin beta barrel and extensive van der Waals interactions of the C18 alkyl chains with the binding site including residues in helices 4 and 5. Mean docking free energies were 8.73-8.93 kcal/mol for SPH and 8.56-8.15 kcal/mol for DMS, and calculated binding constants were ~40 nM for SPH and ~120 nM for DMS. We hypothesize that SPH, DMS, and similar sphingoid bases access the S1R beta barrel via a membrane bilayer pathway. We further propose that the enzymatic control of ceramide concentrations in intracellular membranes as the primary sources of SPH dictates availability of endogenous SPH and DMS to the S1R and the subsequent control of S1R activity within the same cell and/or in cellular environments.
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Affiliation(s)
- Jing Li
- Department of Surgery, School of Medicine, University of Virginia, Charlottesville, VA 22908, USA
| | - Kenneth A. Satyshur
- Small Molecule Screening Facility, Carbone Cancer Center, School of Medicine and Public Health, University of Wisconsin, Madison, WI 53705, USA
| | - Lian-Wang Guo
- Department of Surgery, School of Medicine, University of Virginia, Charlottesville, VA 22908, USA
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA 22908, USA
| | - Arnold E. Ruoho
- Department of Neuroscience, School of Medicine and Public Health, University of Wisconsin, Madison, WI 53705, USA
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4
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Kim HY, Lee JY, Hsieh CJ, Riad A, Izzo NJ, Catalano SM, Graham TJA, Mach RH. Screening of σ 2 Receptor Ligands and In Vivo Evaluation of 11C-Labeled 6,7-Dimethoxy-2-[4-(4-methoxyphenyl)butan-2-yl]-1,2,3,4-tetrahydroisoquinoline for Potential Use as a σ 2 Receptor Brain PET Tracer. J Med Chem 2022; 65:6261-6272. [PMID: 35404616 DOI: 10.1021/acs.jmedchem.2c00191] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
In this study, a panel of 46 compounds containing five different scaffolds known to have high σ2 receptor affinity were screened. 6,7-Dimethoxy-2-[4-(4-methoxyphenyl)butan-2-yl]-1,2,3,4-tetrahydroisoquinoline [(±)-7] (Ki for σ1 = 48.4 ± 7.7 nM, and Ki for σ2 = 0.59 ± 0.02 nM) and its desmethyl analogue, (±)-8 (Ki for σ1 = 108 ± 35 nM, and Ki for σ2 = 4.92 ± 0.59 nM), showed excellent binding affinity and subtype selectivity for σ2 receptors. In vitro cell binding indicated that σ2 receptor binding of [11C]-(±)-7 and [11C]-(±)-8 was dependent on TMEM97 protein expression. In PET studies, the peak brain uptake of [11C]-(±)-7 (8.28 ± 2.52%ID/cc) was higher than that of [11C]-(±)-8 (4.25 ± 0.97%ID/cc) with specific distribution in the cortex and hypothalamus. Brain uptake or tissue binding was selectively inhibited by ligands with different σ2 receptor binding affinities. The results suggest [11C]-(±)-7 can be used as a PET radiotracer for imaging the function of σ2 receptors in central nervous system disorders.
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Affiliation(s)
- Ho Young Kim
- Department of Radiology, University of Pennsylvania, Vagelos Laboratories, 1012, 231 South 34th Street, Philadelphia, Pennsylvania 19104-6323, United States
| | - Ji Youn Lee
- Department of Radiology, University of Pennsylvania, Vagelos Laboratories, 1012, 231 South 34th Street, Philadelphia, Pennsylvania 19104-6323, United States
| | - Chia-Ju Hsieh
- Department of Radiology, University of Pennsylvania, Vagelos Laboratories, 1012, 231 South 34th Street, Philadelphia, Pennsylvania 19104-6323, United States
| | - Aladdin Riad
- Department of Radiology, University of Pennsylvania, Vagelos Laboratories, 1012, 231 South 34th Street, Philadelphia, Pennsylvania 19104-6323, United States
| | - Nicholas J Izzo
- Cognition Therapeutics Inc., Pittsburgh, Pennsylvania 15203-5118, United States
| | - Susan M Catalano
- Cognition Therapeutics Inc., Pittsburgh, Pennsylvania 15203-5118, United States
| | - Thomas J A Graham
- Department of Radiology, University of Pennsylvania, Vagelos Laboratories, 1012, 231 South 34th Street, Philadelphia, Pennsylvania 19104-6323, United States
| | - Robert H Mach
- Department of Radiology, University of Pennsylvania, Vagelos Laboratories, 1012, 231 South 34th Street, Philadelphia, Pennsylvania 19104-6323, United States
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5
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Sałaciak K, Pytka K. Revisiting the sigma-1 receptor as a biological target to treat affective and cognitive disorders. Neurosci Biobehav Rev 2022; 132:1114-1136. [PMID: 34736882 PMCID: PMC8559442 DOI: 10.1016/j.neubiorev.2021.10.037] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 10/25/2021] [Accepted: 10/28/2021] [Indexed: 12/21/2022]
Abstract
Depression and cognitive disorders are diseases with complex and not-fully understood etiology. Unfortunately, the COVID-19 pandemic dramatically increased the prevalence of both conditions. Since the current treatments are inadequate in many patients, there is a constant need for discovering new compounds, which will be more effective in ameliorating depressive symptoms and treating cognitive decline. Proteins attracting much attention as potential targets for drugs treating these conditions are sigma-1 receptors. Sigma-1 receptors are multi-functional proteins localized in endoplasmic reticulum membranes, which play a crucial role in cellular signal transduction by interacting with receptors, ion channels, lipids, and kinases. Changes in their functions and expression may lead to various diseases, including depression or memory impairments. Thus, sigma-1 receptor modulation might be useful in treating these central nervous system diseases. Importantly, two sigma-1 receptor ligands entered clinical trials, showing that this compound group possesses therapeutic potential. Therefore, based on preclinical studies, this review discusses whether the sigma-1 receptor could be a promising target for drugs treating affective and cognitive disorders.
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Affiliation(s)
- Kinga Sałaciak
- Department of Pharmacodynamics, Faculty of Pharmacy, Jagiellonian University Medical College, Medyczna 9, 30-688 Krakow, Poland
| | - Karolina Pytka
- Department of Pharmacodynamics, Faculty of Pharmacy, Jagiellonian University Medical College, Medyczna 9, 30-688 Krakow, Poland.
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6
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Rossino G, Rui M, Linciano P, Rossi D, Boiocchi M, Peviani M, Poggio E, Curti D, Schepmann D, Wünsch B, González-Avendaño M, Vergara-Jaque A, Caballero J, Collina S. Bitopic Sigma 1 Receptor Modulators to Shed Light on Molecular Mechanisms Underpinning Ligand Binding and Receptor Oligomerization. J Med Chem 2021; 64:14997-15016. [PMID: 34624193 DOI: 10.1021/acs.jmedchem.1c00886] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The sigma 1 receptor (S1R) is an enigmatic ligand-operated chaperone involved in many important biological processes, and its functions are not fully understood yet. Herein, we developed a novel series of bitopic S1R ligands as versatile tools to investigate binding processes, allosteric modulation, and the oligomerization mechanism. These molecules have been prepared in the enantiopure form and subjected to a preliminary biological evaluation, while in silico investigations helped to rationalize the results. Compound 7 emerged as the first bitopic S1R ligand endowed with low nanomolar affinity (Ki = 2.6 nM) reported thus far. Computational analyses suggested that 7 may stabilize the open conformation of the S1R by simultaneously binding the occluded primary binding site and a peripheral site on the cytosol-exposed surface. These findings pave the way to new S1R ligands with enhanced activity and/or selectivity, which could also be used as probes for the identification of a potential allosteric site.
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Affiliation(s)
- Giacomo Rossino
- Department of Drug Sciences, University of Pavia, Viale Taramelli 12, 27100 Pavia, Italy
| | - Marta Rui
- Department of Drug Sciences, University of Pavia, Viale Taramelli 12, 27100 Pavia, Italy
| | - Pasquale Linciano
- Department of Drug Sciences, University of Pavia, Viale Taramelli 12, 27100 Pavia, Italy
| | - Daniela Rossi
- Department of Drug Sciences, University of Pavia, Viale Taramelli 12, 27100 Pavia, Italy
| | - Massimo Boiocchi
- Centro Grandi Strumenti, University of Pavia, via Bassi 21, 27100 Pavia, Italy
| | - Marco Peviani
- Department of Biology and Biotechnology "L. Spallanzani", University of Pavia, Via Ferrata 9, 27100 Pavia, Italy
| | - Elena Poggio
- Department of Biology and Biotechnology "L. Spallanzani", University of Pavia, Via Ferrata 9, 27100 Pavia, Italy
| | - Daniela Curti
- Department of Biology and Biotechnology "L. Spallanzani", University of Pavia, Via Ferrata 9, 27100 Pavia, Italy
| | - Dirk Schepmann
- Institute of Pharmaceutical and Medicinal Chemistry, University of Münster, Correnstraße 48, 48149 Münster, Germany
| | - Bernhard Wünsch
- Institute of Pharmaceutical and Medicinal Chemistry, University of Münster, Correnstraße 48, 48149 Münster, Germany
| | - Mariela González-Avendaño
- Center for Bioinformatics and Molecular Simulation, Universidad de Talca, 1 Poniente, 1141 Talca, Chile
| | - Ariela Vergara-Jaque
- Center for Bioinformatics and Molecular Simulation, Universidad de Talca, 1 Poniente, 1141 Talca, Chile
| | - Julio Caballero
- Center for Bioinformatics and Molecular Simulation, Universidad de Talca, 1 Poniente, 1141 Talca, Chile
| | - Simona Collina
- Department of Drug Sciences, University of Pavia, Viale Taramelli 12, 27100 Pavia, Italy
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7
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Dvorácskó S, Lázár L, Fülöp F, Palkó M, Zalán Z, Penke B, Fülöp L, Tömböly C, Bogár F. Novel High Affinity Sigma-1 Receptor Ligands from Minimal Ensemble Docking-Based Virtual Screening. Int J Mol Sci 2021; 22:8112. [PMID: 34360878 PMCID: PMC8347176 DOI: 10.3390/ijms22158112] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2021] [Revised: 07/23/2021] [Accepted: 07/26/2021] [Indexed: 02/07/2023] Open
Abstract
Sigma-1 receptor (S1R) is an intracellular, multi-functional, ligand operated protein that also acts as a chaperone. It is considered as a pluripotent drug target in several pathologies. The publication of agonist and antagonist bound receptor structures has paved the way for receptor-based in silico drug design. However, recent studies on this subject payed no attention to the structural differences of agonist and antagonist binding. In this work, we have developed a new ensemble docking-based virtual screening protocol utilizing both agonist and antagonist bound S1R structures. This protocol was used to screen our in-house compound library. The S1R binding affinities of the 40 highest ranked compounds were measured in competitive radioligand binding assays and the sigma-2 receptor (S2R) affinities of the best S1R binders were also determined. This way three novel high affinity S1R ligands were identified and one of them exhibited a notable S1R/S2R selectivity.
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Affiliation(s)
- Szabolcs Dvorácskó
- Biological Research Centre, Institute of Biochemistry, Eötvös Loránd Research Network (ELKH), H-6726 Szeged, Hungary; (S.D.); (C.T.)
| | - László Lázár
- Institute of Pharmaceutical Chemistry, University of Szeged, H-6720 Szeged, Hungary; (L.L.); (F.F.); (M.P.); (Z.Z.)
| | - Ferenc Fülöp
- Institute of Pharmaceutical Chemistry, University of Szeged, H-6720 Szeged, Hungary; (L.L.); (F.F.); (M.P.); (Z.Z.)
| | - Márta Palkó
- Institute of Pharmaceutical Chemistry, University of Szeged, H-6720 Szeged, Hungary; (L.L.); (F.F.); (M.P.); (Z.Z.)
| | - Zita Zalán
- Institute of Pharmaceutical Chemistry, University of Szeged, H-6720 Szeged, Hungary; (L.L.); (F.F.); (M.P.); (Z.Z.)
| | - Botond Penke
- Department of Medical Chemistry, University of Szeged, H-6720 Szeged, Hungary;
| | - Lívia Fülöp
- Department of Medical Chemistry, University of Szeged, H-6720 Szeged, Hungary;
| | - Csaba Tömböly
- Biological Research Centre, Institute of Biochemistry, Eötvös Loránd Research Network (ELKH), H-6726 Szeged, Hungary; (S.D.); (C.T.)
| | - Ferenc Bogár
- Department of Medical Chemistry, University of Szeged, H-6720 Szeged, Hungary;
- MTA-SZTE Biomimetic Systems Research Group, Eötvös Loránd Research Network (ELKH), H-6720 Szeged, Hungary
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8
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Fallica AN, Pittalà V, Modica MN, Salerno L, Romeo G, Marrazzo A, Helal MA, Intagliata S. Recent Advances in the Development of Sigma Receptor Ligands as Cytotoxic Agents: A Medicinal Chemistry Perspective. J Med Chem 2021; 64:7926-7962. [PMID: 34076441 PMCID: PMC8279423 DOI: 10.1021/acs.jmedchem.0c02265] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
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Since their discovery
as distinct receptor proteins, the specific
physiopathological role of sigma receptors (σRs) has been deeply
investigated. It has been reported that these proteins, classified
into two subtypes indicated as σ1 and σ2, might play a pivotal role in cancer growth, cell proliferation,
and tumor aggressiveness. As a result, the development of selective
σR ligands with potential antitumor properties attracted significant
attention as an emerging theme in cancer research. This perspective
deals with the recent advances of σR ligands as novel cytotoxic
agents, covering articles published between 2010 and 2020. An up-to-date
description of the medicinal chemistry of selective σ1R and σ2R ligands with antiproliferative and cytotoxic
activities has been provided, including major pharmacophore models
and comprehensive structure–activity relationships for each
main class of σR ligands.
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Affiliation(s)
- Antonino N Fallica
- Department of Drug and Health Sciences, University of Catania, Viale A. Doria 6, 95125 Catania, Italy
| | - Valeria Pittalà
- Department of Drug and Health Sciences, University of Catania, Viale A. Doria 6, 95125 Catania, Italy
| | - Maria N Modica
- Department of Drug and Health Sciences, University of Catania, Viale A. Doria 6, 95125 Catania, Italy
| | - Loredana Salerno
- Department of Drug and Health Sciences, University of Catania, Viale A. Doria 6, 95125 Catania, Italy
| | - Giuseppe Romeo
- Department of Drug and Health Sciences, University of Catania, Viale A. Doria 6, 95125 Catania, Italy
| | - Agostino Marrazzo
- Department of Drug and Health Sciences, University of Catania, Viale A. Doria 6, 95125 Catania, Italy
| | - Mohamed A Helal
- University of Science and Technology, Biomedical Sciences Program, Zewail City of Science and Technology, October Gardens, sixth of October, Giza 12578, Egypt.,Medicinal Chemistry Department, Faculty of Pharmacy, Suez Canal University, Ismailia 41522, Egypt
| | - Sebastiano Intagliata
- Department of Drug and Health Sciences, University of Catania, Viale A. Doria 6, 95125 Catania, Italy
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9
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Zhemkov V, Ditlev JA, Lee WR, Wilson M, Liou J, Rosen MK, Bezprozvanny I. The role of sigma 1 receptor in organization of endoplasmic reticulum signaling microdomains. eLife 2021; 10:e65192. [PMID: 33973848 PMCID: PMC8112866 DOI: 10.7554/elife.65192] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Accepted: 04/29/2021] [Indexed: 12/12/2022] Open
Abstract
Sigma 1 receptor (S1R) is a 223-amino-acid-long transmembrane endoplasmic reticulum (ER) protein. S1R modulates activity of multiple effector proteins and is a well-established drug target. However, signaling functions of S1R in cells are poorly understood. Here, we test the hypothesis that biological activity of S1R in cells can be explained by its ability to interact with cholesterol and to form cholesterol-enriched microdomains in the ER membrane. By performing experiments in reduced reconstitution systems, we demonstrate direct effects of cholesterol on S1R clustering. We identify a novel cholesterol-binding motif in the transmembrane region of human S1R. Mutations of this motif impair association of recombinant S1R with cholesterol beads, affect S1R clustering in vitro and disrupt S1R subcellular localization. We demonstrate that S1R-induced membrane microdomains have increased local membrane thickness and that increased local cholesterol concentration and/or membrane thickness in these microdomains can modulate signaling of inositol-requiring enzyme 1α in the ER. Further, S1R agonists cause disruption of S1R clusters, suggesting that biological activity of S1R agonists is linked to remodeling of ER membrane microdomains. Our results provide novel insights into S1R-mediated signaling mechanisms in cells.
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Affiliation(s)
- Vladimir Zhemkov
- Department of Physiology, UT Southwestern Medical Center at DallasDallasUnited States
| | - Jonathon A Ditlev
- Department of Biophysics, Howard Hughes Medical Institute, UT Southwestern Medical Center at DallasDallasUnited States
| | - Wan-Ru Lee
- Department of Physiology, UT Southwestern Medical Center at DallasDallasUnited States
| | - Mikaela Wilson
- Department of Physiology, UT Southwestern Medical Center at DallasDallasUnited States
| | - Jen Liou
- Department of Physiology, UT Southwestern Medical Center at DallasDallasUnited States
| | - Michael K Rosen
- Department of Biophysics, Howard Hughes Medical Institute, UT Southwestern Medical Center at DallasDallasUnited States
| | - Ilya Bezprozvanny
- Department of Physiology, UT Southwestern Medical Center at DallasDallasUnited States
- Laboratory of Molecular Neurodegeneration, Peter the Great St. Petersburg State Polytechnic UniversitySt. PetersburgRussian Federation
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10
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Arun AS, Eddings CR, Wilson KL. Novel missense alleles of SIGMAR1 as tools to understand emerin-dependent gene silencing in response to cocaine. Exp Biol Med (Maywood) 2019; 244:1354-1361. [PMID: 31324122 PMCID: PMC6880142 DOI: 10.1177/1535370219863444] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Accepted: 06/23/2019] [Indexed: 12/18/2022] Open
Abstract
Sigma-1 receptor (Sigma1R; SIGMAR1 ), an integral membrane protein of the endoplasmic reticulum and nuclear envelope, has a hydrophobic drug-binding pocket that binds with high affinity to addictive drugs (cocaine, methamphetamine) and therapeutics used to treat a wide spectrum of neurological disorders. Cocaine enhances Sigma1R association with three nuclear lamina proteins (emerin, lamin A/C, BANF1), causing Sigma1R-dependent and emerin-dependent recruitment and transcriptional repression of a gene, MAOB1 , involved in dopamine removal from neural synapses. The mechanism of Sigma1R association with emerin and the molecular impact of cocaine on their association are unknown. Mutations in Sigma1R, as a proposed regulator or mis-regulator of the nuclear lamina, have the potential to alter nuclear lamina function in brain or other tissues. We examined the frequency of SIGMAR1 missense alleles among 60,706 unrelated individuals in the ExAC database. We identified two novel SIGMAR1 missense variants of particular interest due to their frequency and potential to impact molecular association with emerin or other nuclear lamina proteins. Variant p.Q2P was widespread in ExAC (overall allele frequency 18.4%) with broad ethnic distribution among non-Finnish Europeans, Africans, South Asians, Latinx (allele frequencies ∼15% to 23%), and East Asians (∼38%). The p.R208W allele was identified in ∼0.78% of individuals overall with enrichment in Africans, Latinx, and East Asians (∼1.9–2.9%). These and other novel Sigma1R variants provide tools for future studies to determine the molecular basis of Sigma1R association with emerin and the mechanism of nuclear lamina misregulation by cocaine and potentially other Sigma1R agonists.
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Affiliation(s)
- Adith S Arun
- Department of Cell Biology, Johns Hopkins University
School of Medicine, Baltimore, MD 21205, USA
| | - Chelsy R Eddings
- Department of Cell Biology, Johns Hopkins University
School of Medicine, Baltimore, MD 21205, USA
| | - Katherine L Wilson
- Department of Cell Biology, Johns Hopkins University
School of Medicine, Baltimore, MD 21205, USA
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11
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Alamri MA, Alamri MA. Pharmacophore and docking-based sequential virtual screening for the identification of novel Sigma 1 receptor ligands. Bioinformation 2019; 15:586-595. [PMID: 31719769 PMCID: PMC6822515 DOI: 10.6026/97320630015586] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2019] [Accepted: 08/31/2019] [Indexed: 11/23/2022] Open
Abstract
Sigma 1 receptor (σ1), a small transmembrane protein expressed in most human cells participates in modulating the function of other membrane proteins such as G protein coupled receptors and ion channels. Several ligands targeting this receptor are currently in clinical trials for the treatment of Alzheimer's disease, ischemic stroke and neuro-pathic pain. Hence, this receptor has emerged as an attractive target for the treatment of neuro-pathological diseases with unmet medical needs. It is of interest to identify and characterise novelσ1 receptor ligands with different chemical scaffolds using computer-aided drug designing approach. In this work, a GPCR-focused chemical library consisting of 8543 compounds was screened by pharmacophore and docking-based virtual screening methods using LigandScout 4.3 and Autodock Vina 1.1.2 in PyRx 0.8, respectively. The pharmacophore model was constructed based on the interactions of a selective agonist and another antagonist ligand with high binding affinity to the human σ1receptors. Candidate compounds were filtered sequentially by pharmacophore-fit scores, docking energy scores, drug-likeness filters and ADMET properties. The binding mode and pharmacophore mapping of candidate compounds were analysed by Autodock Vina 1.1.2 and LigandScout 4.3 programs, respectively. A pharmacophore model composed of three hydrophobic and positive ionizable features with recognized geometry was built and used as a 3D query for screening a GPCR-focused chemical library by LigandScout 4.3 program. Among the screened 8543 compounds, 159 candidate compounds were obtained from pharmacophore-based screening. 45 compounds among them bound to σ 1receptor with high binding-affinity scores in comparison to the co-crystallized ligand. Amongst these, top five candidate compounds with excellent druglikeness and ADMET properties were selected. These five candidate compounds may act as potential σ1 receptor ligands.
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Affiliation(s)
- Mubarak A Alamri
- Department of Pharmaceutical Chemistry, College of Pharmacy, Prince Sattam Bin Abdulaziz University, Alkharj 11942, Saudi Arabia
| | - Mohammed A Alamri
- Department of Pharmacology, College of Pharmacy, Prince Sattam Bin Abdulaziz University, Alkharj 11942, Saudi Arabia
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12
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Ryskamp DA, Korban S, Zhemkov V, Kraskovskaya N, Bezprozvanny I. Neuronal Sigma-1 Receptors: Signaling Functions and Protective Roles in Neurodegenerative Diseases. Front Neurosci 2019; 13:862. [PMID: 31551669 PMCID: PMC6736580 DOI: 10.3389/fnins.2019.00862] [Citation(s) in RCA: 104] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Accepted: 07/31/2019] [Indexed: 12/12/2022] Open
Abstract
Sigma-1 receptor (S1R) is a multi-functional, ligand-operated protein situated in endoplasmic reticulum (ER) membranes and changes in its function and/or expression have been associated with various neurological disorders including amyotrophic lateral sclerosis/frontotemporal dementia, Alzheimer's (AD) and Huntington's diseases (HD). S1R agonists are broadly neuroprotective and this is achieved through a diversity of S1R-mediated signaling functions that are generally pro-survival and anti-apoptotic; yet, relatively little is known regarding the exact mechanisms of receptor functioning at the molecular level. This review summarizes therapeutically relevant mechanisms by which S1R modulates neurophysiology and implements neuroprotective functions in neurodegenerative diseases. These mechanisms are diverse due to the fact that S1R can bind to and modulate a large range of client proteins, including many ion channels in both ER and plasma membranes. We summarize the effect of S1R on its interaction partners and consider some of the cell type- and disease-specific aspects of these actions. Besides direct protein interactions in the endoplasmic reticulum, S1R is likely to function at the cellular/interorganellar level by altering the activity of several plasmalemmal ion channels through control of trafficking, which may help to reduce excitotoxicity. Moreover, S1R is situated in lipid rafts where it binds cholesterol and regulates lipid and protein trafficking and calcium flux at the mitochondrial-associated membrane (MAM) domain. This may have important implications for MAM stability and function in neurodegenerative diseases as well as cellular bioenergetics. We also summarize the structural and biochemical features of S1R proposed to underlie its activity. In conclusion, S1R is incredibly versatile in its ability to foster neuronal homeostasis in the context of several neurodegenerative disorders.
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Affiliation(s)
- Daniel A. Ryskamp
- Department of Physiology, UT Southwestern Medical Center at Dallas, Dallas, TX, United States
| | - Svetlana Korban
- Laboratory of Molecular Neurodegeneration, Peter the Great St. Petersburg State Polytechnic University, Saint Petersburg, Russia
| | - Vladimir Zhemkov
- Department of Physiology, UT Southwestern Medical Center at Dallas, Dallas, TX, United States
| | - Nina Kraskovskaya
- Laboratory of Molecular Neurodegeneration, Peter the Great St. Petersburg State Polytechnic University, Saint Petersburg, Russia
| | - Ilya Bezprozvanny
- Department of Physiology, UT Southwestern Medical Center at Dallas, Dallas, TX, United States
- Laboratory of Molecular Neurodegeneration, Peter the Great St. Petersburg State Polytechnic University, Saint Petersburg, Russia
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13
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Yang K, Wang C, Sun T. The Roles of Intracellular Chaperone Proteins, Sigma Receptors, in Parkinson's Disease (PD) and Major Depressive Disorder (MDD). Front Pharmacol 2019; 10:528. [PMID: 31178723 PMCID: PMC6537631 DOI: 10.3389/fphar.2019.00528] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Accepted: 04/26/2019] [Indexed: 12/19/2022] Open
Abstract
Sigma receptors, including Sigma-1 receptors and Sigma-2 receptors, are highly expressed in the CNS. They are intracellular chaperone proteins. Sigma-1 receptors localize mainly at the mitochondria-associated endoplasmic reticulum (ER) membrane (MAM). Upon stimulation, they translocate from MAM to plasma membrane (PM) and nucleus, where they interact with many proteins and ion channels. Sigma-1 receptor could interact with itself to form oligomers, its oligomerization states affect its ability to interact with client proteins including ion channels and BiP. Sigma-1 receptor shows high affinity for many unrelated and structurally diverse ligands, but the mechanism for this diverse drug receptor interaction remains unknown. Sigma-1 receptors also directly bind many proteins including G protein-coupled receptors (GPCRs) and ion channels. In recent years, significant progress has been made in our understanding of roles of the Sigma-1 receptors in normal and pathological conditions, but more studies are still required for the Sigma-2 receptors. The physiological roles of Sigma-1 receptors in the CNS are discussed. They can modulate the activity of many ion channels including voltage-dependent ion channels including Ca2+, Na+, K+ channels and NMDAR, thus affecting neuronal excitability and synaptic activity. They are also involved in synaptic plasticity and learning and memory. Moreover, the activation of Sigma receptors protects neurons from death via the modulation of ER stress, neuroinflammation, and Ca2+ homeostasis. Evidences about the involvement of Sigma-1 receptors in Parkinson’s disease (PD) and Major Depressive Disorder (MDD) are also presented, indicating Sigma-1 receptors might be promising targets for pharmacologically treating PD and MDD.
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Affiliation(s)
- Kai Yang
- School of Chemistry, Chemical Engineering and Life Science, Wuhan University of Technology, Wuhan, China
| | - Changcai Wang
- School of Chemistry, Chemical Engineering and Life Science, Wuhan University of Technology, Wuhan, China
| | - Taolei Sun
- School of Chemistry, Chemical Engineering and Life Science, Wuhan University of Technology, Wuhan, China.,State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan, China
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14
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Morales-Lázaro SL, González-Ramírez R, Rosenbaum T. Molecular Interplay Between the Sigma-1 Receptor, Steroids, and Ion Channels. Front Pharmacol 2019; 10:419. [PMID: 31068816 PMCID: PMC6491805 DOI: 10.3389/fphar.2019.00419] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2019] [Accepted: 04/03/2019] [Indexed: 11/17/2022] Open
Abstract
Cell excitability is tightly regulated by the activity of ion channels that allow for the passage of ions across cell membranes. Ion channel activity is controlled by different mechanisms that change their gating properties, expression or abundance in the cell membrane. The latter can be achieved by forming complexes with a diversity of proteins like chaperones such as the Sigma-1 receptor (Sig-1R), which is one with unique features and exhibits a role as a ligand-operated chaperone. This molecule also displays high intracellular mobility according to its activation level since, depletion of internal Ca+2 stores or the presence of specific ligands, produce Sig-1R’s mobilization from the endoplasmic reticulum toward the plasma membrane or nuclear envelope. The function of the Sig-1R as a chaperone is regulated by synthetic and endogenous ligands, with some of these compounds being a steroids and acting as key endogenous modifiers of the actions of the Sig-1R. There are cases in the literature that exemplify the close relationship between the actions of steroids on the Sig-1R and the resulting negative or positive effects on ion channel function/abundance. Such interactions have been shown to importantly influence the physiology of mammalian cells leading to changes in their excitability. The present review focuses on describing how the Sig-1R regulates the functional properties and the expression of some sodium, calcium, potassium, and TRP ion channels in the presence of steroids and the physiological consequences of these interplays at the cellular level are also discussed.
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Affiliation(s)
- Sara L Morales-Lázaro
- Departamento de Neurociencia Cognitiva, División de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Ricardo González-Ramírez
- Departamento de Biología Molecular e Histocompatibilidad, Hospital General Dr. Manuel Gea González, Secretaría de Salud, Ciudad de México, Mexico
| | - Tamara Rosenbaum
- Departamento de Neurociencia Cognitiva, División de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
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15
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Tesei A, Cortesi M, Zamagni A, Arienti C, Pignatta S, Zanoni M, Paolillo M, Curti D, Rui M, Rossi D, Collina S. Sigma Receptors as Endoplasmic Reticulum Stress "Gatekeepers" and their Modulators as Emerging New Weapons in the Fight Against Cancer. Front Pharmacol 2018; 9:711. [PMID: 30042674 PMCID: PMC6048940 DOI: 10.3389/fphar.2018.00711] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Accepted: 06/12/2018] [Indexed: 12/13/2022] Open
Abstract
Despite the interest aroused by sigma receptors (SRs) in the area of oncology, their role in tumor biology remains enigmatic. The predominant subcellular localization and main site of activity of SRs are the endoplasmic reticulum (ER). Current literature data, including recent findings on the sigma 2 receptor subtype (S2R) identity, suggest that SRs may play a role as ER stress gatekeepers. Although SR endogenous ligands are still unknown, a wide series of structurally unrelated compounds able to bind SRs have been identified. Currently, the identification of novel antiproliferative molecules acting via SR interaction is a challenging task for both academia and industry, as shown by the fact that novel anticancer drugs targeting SRs are in the preclinical-stage pipeline of pharmaceutical companies (i.e., Anavex Corp. and Accuronix). So far, no clinically available anticancer drugs targeting SRs are still available. The present review focuses literature advancements and provides a state-of-the-art overview of SRs, with emphasis on their involvement in cancer biology and on the role of SR modulators as anticancer agents. Findings from preclinical studies on novel anticancer drugs targeting SRs are presented in brief.
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Affiliation(s)
- Anna Tesei
- Biosciences Laboratory, Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRCCS), Meldola, Italy
| | - Michela Cortesi
- Biosciences Laboratory, Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRCCS), Meldola, Italy
| | - Alice Zamagni
- Biosciences Laboratory, Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRCCS), Meldola, Italy
| | - Chiara Arienti
- Biosciences Laboratory, Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRCCS), Meldola, Italy
| | - Sara Pignatta
- Biosciences Laboratory, Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRCCS), Meldola, Italy
| | - Michele Zanoni
- Biosciences Laboratory, Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRCCS), Meldola, Italy
| | - Mayra Paolillo
- Pharmacology Section, Department of Drug Sciences, University of Pavia, Pavia, Italy
| | - Daniela Curti
- Laboratory of Cellular and Molecular Neuropharmacology, Department of Biology and Biotechnology 'L. Spallanzani', University of Pavia, Pavia, Italy
| | - Marta Rui
- Medicinal Chemistry and Pharmaceutical Technology Section, Department of Drug Sciences, University of Pavia, Pavia, Italy
| | - Daniela Rossi
- Medicinal Chemistry and Pharmaceutical Technology Section, Department of Drug Sciences, University of Pavia, Pavia, Italy
| | - Simona Collina
- Medicinal Chemistry and Pharmaceutical Technology Section, Department of Drug Sciences, University of Pavia, Pavia, Italy
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16
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Hajipour AR, Khorsandi Z, Fakhari F, Mortazavi M, Farrokhpour H. A Comparative Study between Co‐ and CoFe
2
O
4
‐NPs Catalytic Activities in Synthesis of Flavone Derivatives; Study of Their Interactions with Estrogen Receptor by Molecular Docking. ChemistrySelect 2018. [DOI: 10.1002/slct.201702702] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Affiliation(s)
- Abdol R. Hajipour
- Department of ChemistryIsfahan University of Technology Isfahan 84156 Iran
- Department of NeuroscienceUniversity of WisconsinMedical School, Madison WI53706-1532 USA
| | - Zahra Khorsandi
- Department of ChemistryIsfahan University of Technology Isfahan 84156 Iran
| | - Farzaneh Fakhari
- Department of ChemistryIsfahan University of Technology Isfahan 84156 Iran
| | - Maryam Mortazavi
- Department of Chemical industryfaculty of Shiraz daughters branchtrchnical and vocational university (TVU) Shiraz 71454 Iran
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17
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Penke B, Fülöp L, Szűcs M, Frecska E. The Role of Sigma-1 Receptor, an Intracellular Chaperone in Neurodegenerative Diseases. Curr Neuropharmacol 2018; 16:97-116. [PMID: 28554311 PMCID: PMC5771390 DOI: 10.2174/1570159x15666170529104323] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Revised: 04/15/2017] [Accepted: 05/25/2017] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Widespread protein aggregation occurs in the living system under stress or during aging, owing to disturbance of endoplasmic reticulum (ER) proteostasis. Many neurodegenerative diseases may have a common mechanism: the failure of protein homeostasis. Perturbation of ER results in unfolded protein response (UPR). Prolonged chronical UPR may activate apoptotic pathways and cause cell death. METHODS Research articles on Sigma-1 receptor were reviewed. RESULTS ER is associated to mitochondria by the mitochondria-associated ER-membrane, MAM. The sigma-1 receptor (Sig-1R), a well-known ER-chaperone localizes in the MAM. It serves for Ca2+-signaling between the ER and mitochondria, involved in ion channel activities and especially important during neuronal differentiation. Sig-1R acts as central modulator in inter-organelle signaling. Sig-1R helps cell survival by attenuating ER-stress. According to sequence based predictions Sig-1R is a 223 amino acid protein with two transmembrane (2TM) domains. The X-ray structure of the Sig-1R [1] showed a membrane-bound trimeric assembly with one transmembrane (1TM) region. Despite the in vitro determined assembly, the results of in vivo studies are rather consistent with the 2TM structure. The receptor has unique and versatile pharmacological profile. Dimethyl tryptamine (DMT) and neuroactive steroids are endogenous ligands that activate Sig-1R. The receptor has a plethora of interacting client proteins. Sig-1R exists in oligomeric structures (dimer-trimer-octamer-multimer) and this fact may explain interaction with diverse proteins. CONCLUSION Sig-1R agonists have been used in the treatment of different neurodegenerative diseases, e.g. Alzheimer's and Parkinson's diseases (AD and PD) and amyotrophic lateral sclerosis. Utilization of Sig-1R agents early in AD and similar other diseases has remained an overlooked therapeutic opportunity.
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Affiliation(s)
- Botond Penke
- University of Szeged, Department of Medical Chemistry, Faculty of Medicine, Szeged, Hungary
| | - Lívia Fülöp
- University of Szeged, Department of Medical Chemistry, Faculty of Medicine, Szeged, Hungary
| | - Mária Szűcs
- University of Szeged, Department of Medical Chemistry, Faculty of Medicine, Szeged, Hungary
| | - Ede Frecska
- University of Debrecen, Department of Psychiatry, Faculty of Medicine, Debrecen, Hungary
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18
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Gueguinou M, Crottès D, Chantôme A, Rapetti-Mauss R, Potier-Cartereau M, Clarysse L, Girault A, Fourbon Y, Jézéquel P, Guérin-Charbonnel C, Fromont G, Martin P, Pellissier B, Schiappa R, Chamorey E, Mignen O, Uguen A, Borgese F, Vandier C, Soriani O. The SigmaR1 chaperone drives breast and colorectal cancer cell migration by tuning SK3-dependent Ca 2+ homeostasis. Oncogene 2017; 36:3640-3647. [PMID: 28114279 DOI: 10.1038/onc.2016.501] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Revised: 11/19/2016] [Accepted: 11/28/2016] [Indexed: 12/21/2022]
Abstract
The remodeling of calcium homeostasis contributes to the cancer hallmarks and the molecular mechanisms involved in calcium channel regulation in tumors remain to be characterized. Here, we report that SigmaR1, a stress-activated chaperone, is required to increase calcium influx by triggering the coupling between SK3, a Ca2+-activated K+ channel (KCNN3) and the voltage-independent calcium channel Orai1. We show that SigmaR1 physically binds SK3 in BC cells. Inhibition of SigmaR1 activity, either by molecular silencing or by the use of sigma ligand (igmesine), decreased SK3 current and Ca2+ entry in breast cancer (BC) and colorectal cancer (CRC) cells. Interestingly, SigmaR1 inhibition diminished SK3 and/or Orai1 levels in lipid nanodomains isolated from BC cells. Analyses of tissue microarray from CRC patients showed higher SigmaR1 expression levels in cancer samples and a correlation with tumor grade. Moreover, the exploration of a cohort of 4937 BC patients indicated that high expression of SigmaR1 and Orai1 channels was significantly correlated to a lower overall survival. As the SK3/Orai1 tandem drives invasive process in CRC and bone metastasis progression in BC, our results may inaugurate innovative therapeutic approaches targeting SigmaR1 to control the remodeling of Ca2+ homeostasis in epithelial cancers.
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Affiliation(s)
- M Gueguinou
- Inserm-University U1069 Nutrition, Croissance et Cancer, Tours, France
| | - D Crottès
- Université Côte d'Azur, CNRS, Inserm, iBV, France
| | - A Chantôme
- Inserm-University U1069 Nutrition, Croissance et Cancer, Tours, France
| | | | | | - L Clarysse
- Inserm-University U1069 Nutrition, Croissance et Cancer, Tours, France
| | - A Girault
- Inserm-University U1069 Nutrition, Croissance et Cancer, Tours, France
| | - Y Fourbon
- Inserm-University U1069 Nutrition, Croissance et Cancer, Tours, France
| | - P Jézéquel
- Unité de Bioinfomique, Institut de Cancérologie de L'Ouest - René Gauducheau, Centre de Recherche en Cancérologie, UMR-INSERM 892, St Herblain, France
| | - C Guérin-Charbonnel
- Unité de Bioinfomique, Institut de Cancérologie de L'Ouest - René Gauducheau, Centre de Recherche en Cancérologie, UMR-INSERM 892, St Herblain, France
| | - G Fromont
- Inserm-University U1069 Nutrition, Croissance et Cancer, Tours, France
- Service d'Anatomie Pathologique, Hopital Bretonneau, CHRU Tours, Tours, France
| | - P Martin
- Université Côte d'Azur, CNRS, Inserm, iBV, France
| | - B Pellissier
- Université Côte d'Azur, CNRS, Inserm, iBV, France
| | - R Schiappa
- Unité d'Epidémiologie et Biostatistiques (UEB), Centre Antoine Lacassagne, Nice, France
| | - E Chamorey
- Unité d'Epidémiologie et Biostatistiques (UEB), Centre Antoine Lacassagne, Nice, France
| | - O Mignen
- Department of Pathology, Inserm U1078, Brest University Hospital, Brest, France
| | - A Uguen
- Department of Pathology, Inserm U1078, Brest University Hospital, Brest, France
| | - F Borgese
- Université Côte d'Azur, CNRS, Inserm, iBV, France
| | - C Vandier
- Inserm-University U1069 Nutrition, Croissance et Cancer, Tours, France
| | - O Soriani
- Université Côte d'Azur, CNRS, Inserm, iBV, France
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19
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Chen T, Tanaka M, Wang Y, Sha S, Furuya K, Chen L, Sokabe M. Neurosteroid dehydroepiandrosterone enhances activity and trafficking of astrocytic GLT-1 via σ 1 receptor-mediated PKC activation in the hippocampal dentate gyrus of rats. Glia 2017; 65:1491-1503. [PMID: 28581152 DOI: 10.1002/glia.23175] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Revised: 05/14/2017] [Accepted: 05/15/2017] [Indexed: 11/08/2022]
Abstract
Neurosteroid dehydroepiandrosterone (DHEA) has been reported to exert a potent neuroprotective effect against glutamate-induced excitotoxicity. However, the underlying mechanism remains to be elucidated. One of the possible mechanisms may be an involvement of astrocytic glutamate transporter subtype-1 (GLT-1) that can quickly clear spilled glutamate at the synapse to prevent excitotoxicity. To examine the effect of DHEA on GLT-1 activity, we measured synaptically induced glial depolarization (SIGD) in the dentate gyrus (DG) of adult rats by applying an optical recording technique to the hippocampal slices stained with voltage-sensitive dye RH155. Bath-application of DHEA for 10 min dose-dependently increased SIGD without changing presynaptic glutamate releases, which was sensitive to the GLT-1 blocker DHK. Patch-clamp recordings in astrocytes showed that an application of 50 μM DHEA increased glutamate-evoked inward currents (Iglu) by approximately 1.5-fold, which was dependent on the GLT-1 activity. In addition, the level of biotinylated GLT-1 protein in the surface of astrocytes was significantly elevated by DHEA. The DHEA-increased SIGD, Iglu, and GLT-1 translocation to the cell surface were blocked by the σ1 R antagonist NE100 and mimicked by the σ1 R agonist PRE084. DHEA elevated the phosphorylation level of PKC in a σ1 R-dependent manner. Furthermore, the PKC inhibitor chelerythrine could prevent the DHEA-increased SIGD, Iglu, and GLT-1 translocation. Collectively, present results suggest that DHEA enhances the activity and translocation to cell surface of astrocytic GLT-1 mainly via σ1 R-mediated PKC cascade.
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Affiliation(s)
- Tingting Chen
- Department of Physiology, Laboratory of Reproductive Medicine, Nanjing Medical University, Tianyuan East Road 818, Nanjing, China
| | - Motoki Tanaka
- Mechanobiology Laboratory, Nagoya University Graduate School of Medicine, 65 Tsurumai, Nagoya, 466-8550, Japan
| | - Ya Wang
- Department of Physiology, Laboratory of Reproductive Medicine, Nanjing Medical University, Tianyuan East Road 818, Nanjing, China
| | - Sha Sha
- Department of Physiology, Laboratory of Reproductive Medicine, Nanjing Medical University, Tianyuan East Road 818, Nanjing, China
| | - Kishio Furuya
- ICORP/SORST Cell Mechanosensing, JST, 65 Tsurumai, Nagoya, 466-8550, Japan
| | - Ling Chen
- Department of Physiology, Laboratory of Reproductive Medicine, Nanjing Medical University, Tianyuan East Road 818, Nanjing, China.,Mechanobiology Laboratory, Nagoya University Graduate School of Medicine, 65 Tsurumai, Nagoya, 466-8550, Japan
| | - Masahiro Sokabe
- Mechanobiology Laboratory, Nagoya University Graduate School of Medicine, 65 Tsurumai, Nagoya, 466-8550, Japan.,ICORP/SORST Cell Mechanosensing, JST, 65 Tsurumai, Nagoya, 466-8550, Japan
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20
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Katz JL, Hiranita T, Hong WC, Job MO, McCurdy CR. A Role for Sigma Receptors in Stimulant Self-Administration and Addiction. Handb Exp Pharmacol 2017; 244:177-218. [PMID: 28110353 DOI: 10.1007/164_2016_94] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Sigma receptors (σRs) are structurally unique proteins that function intracellularly as chaperones. Historically, σRs have been implicated as modulators of psychomotor stimulant effects and have at times been proposed as potential avenues for modifying stimulant abuse. However, the influence of ligands for σRs on the effects of stimulants, such as cocaine or methamphetamine, in various preclinical procedures related to drug abuse has been varied. The present paper reviews the effects of σR agonists and antagonists in three particularly relevant procedures: stimulant discrimination, place conditioning, and self-administration. The literature to date suggests limited σR involvement in the discriminative-stimulus effects of psychomotor stimulants, either with σR agonists substituting for the stimulant or with σR antagonists blocking stimulant effects. In contrast, studies of place conditioning suggest that administration of σR antagonists or down-regulation of σR protein can block the place conditioning induced by stimulants. Despite place conditioning results, selective σR antagonists are inactive in blocking the self-administration of stimulants. However, compounds binding to the dopamine transporter and blocking σRs can selectively decrease stimulant self-administration. Further, after self-administration of stimulants, σR agonists are self-administered, an effect not seen in subjects without that specific history. These findings suggest that stimulants induce unique changes in σR activity, and once established, the changes induced create redundant, and dopamine independent reinforcement pathways. Concomitant targeting of both dopaminergic pathways and σR proteins produces a selective antagonism of those pathways, suggesting new avenues for combination chemotherapies to specifically combat stimulant abuse.
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Affiliation(s)
- Jonathan L Katz
- Psychobiology Section, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Department of Health and Human Services, Baltimore, MD, 21224, USA.
| | - Takato Hiranita
- Psychobiology Section, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Department of Health and Human Services, Baltimore, MD, 21224, USA
| | - Weimin C Hong
- Department of Pharmaceutical Sciences, Butler University, Indianapolis, IN, 46208, USA
| | - Martin O Job
- Psychobiology Section, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Department of Health and Human Services, Baltimore, MD, 21224, USA
| | - Christopher R McCurdy
- Department of BioMolecular Sciences, School of Pharmacy, University of Mississippi, Oxford, MS, 38677, USA
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21
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Ossa F, Schnell JR, Ortega-Roldan JL. A Review of the Human Sigma-1 Receptor Structure. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 964:15-29. [PMID: 28315262 DOI: 10.1007/978-3-319-50174-1_3] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
The Sigma-1 Receptor (S1R) is a small, ligand-regulated integral membrane protein involved in cell homeostasis and the cellular stress response. The receptor has a multitude of protein and small molecule interaction partners with therapeutic potential. Newly reported structures of the human S1R in ligand-bound states provides essential insights into small molecule binding in the context of the overall protein structure. The structure also raises many interesting questions and provides an excellent starting point for understanding the molecular tricks employed by this small membrane receptor to modulate a large number of signaling events. Here, we review insights from the structures of ligand-bound S1R in the context of previous biochemical studies and propose, from a structural viewpoint, a set of important future directions.
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Affiliation(s)
- Felipe Ossa
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK
| | - Jason R Schnell
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford, OX1 3QU, UK.
| | - José Luis Ortega-Roldan
- School of Biosciences, University of Kent, Stacey Building, Room 215B, Canterbury, CT2 7NJ, UK
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22
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Alon A, Schmidt H, Zheng S, Kruse AC. Structural Perspectives on Sigma-1 Receptor Function. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 964:5-13. [PMID: 28315261 DOI: 10.1007/978-3-319-50174-1_2] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The sigma-1 receptor is an enigmatic ER-resident transmembrane protein linked to a variety of human diseases. Although the receptor was first cloned 20 years ago, the molecular structure of the protein and the mechanistic basis for its interaction with drug-like small molecules have remained unclear until recently. The determination of the first crystal structure of human sigma-1 offered the first detailed views of the sigma-1 architecture, and revealed an unusual overall fold with a single transmembrane helix in each protomer. The structure shows an overall trimeric receptor arrangement, and each protomer binds a single ligand molecule at the center of its carboxy-terminal domain. These results offer detailed molecular views of receptor structure, oligomerization, and ligand recognition, providing a framework for the next era of sigma-1 research.
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Affiliation(s)
- Assaf Alon
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, 02115, USA
| | - Hayden Schmidt
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, 02115, USA
| | - Sanduo Zheng
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, 02115, USA
| | - Andrew C Kruse
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, 02115, USA.
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23
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Merlos M, Burgueño J, Portillo-Salido E, Plata-Salamán CR, Vela JM. Pharmacological Modulation of the Sigma 1 Receptor and the Treatment of Pain. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 964:85-107. [PMID: 28315267 DOI: 10.1007/978-3-319-50174-1_8] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
There is a critical need for new analgesics acting through new mechanisms of action, which could increase the efficacy with respect to existing therapies and reduce their unwanted effects. Current preclinical evidence supports the modulatory role of sigma-1 receptors (σ1R) in nociception, mainly based on the pain-attenuated phenotype of σ1R knockout mice and on the antinociceptive effect exerted by σ1R antagonists on pains of different etiologies. σ1R is highly expressed in different pain areas of the CNS and the periphery (particularly dorsal root ganglia), and interacts and modulates the functionality of different receptors and ion channels . The antagonism of σ1R leads to decreased amplification of pain signaling within the spinal cord (central sensitization), but recent data also support a role at the periphery. σ1R antagonists have consistently demonstrated efficacy in neuropathic pain , but also in other types of pain including inflammatory, orofacial, visceral, and post-operative pain. Apart from acting alone, when combined with opioids, σ1R antagonists enhance opioid analgesia but not opioid-induced unwanted effects. Interestingly, unlike opioids, σ1R antagonists do not modify normal sensory mechanical and thermal sensitivity thresholds but they exert antihypersensitive effects in sensitizing conditions, enabling the reversal of nociceptive thresholds back to normal values. Accordingly, σ1R antagonists are not strictly analgesics; they are antiallodynic and antihyperalgesic drugs acting when the system is sensitized following prolonged noxious stimulation or persistent abnormal afferent input (e.g., secondary to nerve injury). These are distinctive features allowing σ1R antagonists to exert a modulatory effect specifically in pathophysiological conditions such as chronic pain .
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Affiliation(s)
- Manuel Merlos
- Drug Discovery and Preclinical Development, ESTEVE. Parc Científic de Barcelona, Baldiri Reixac 4-8, 08028, Barcelona, Spain
| | - Javier Burgueño
- Drug Discovery and Preclinical Development, ESTEVE. Parc Científic de Barcelona, Baldiri Reixac 4-8, 08028, Barcelona, Spain
| | - Enrique Portillo-Salido
- Drug Discovery and Preclinical Development, ESTEVE. Parc Científic de Barcelona, Baldiri Reixac 4-8, 08028, Barcelona, Spain
| | - Carlos Ramón Plata-Salamán
- Drug Discovery and Preclinical Development, ESTEVE. Parc Científic de Barcelona, Baldiri Reixac 4-8, 08028, Barcelona, Spain
| | - José Miguel Vela
- Drug Discovery and Preclinical Development, ESTEVE. Parc Científic de Barcelona, Baldiri Reixac 4-8, 08028, Barcelona, Spain.
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24
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Abstract
There is a critical need for new analgesics acting through new mechanisms of action, which could increase the efficacy respect to existing therapies and/or reduce their unwanted effects. Current preclinical evidence supports the modulatory role of the sigma-1 receptor (σ1R) in nociception, mainly based on the pain-attenuated phenotype of σ1R knockout mice and on the antinociceptive effect exerted by σ1R antagonists on pain of different etiology, very consistently in neuropathic pain, but also in nociceptive, inflammatory, and visceral pain. σ1R is highly expressed in different pain areas of the CNS and the periphery, particularly dorsal root ganglia (DRG), and interacts and modulates the functionality of different receptors and ion channels. Accordingly, antinociceptive effects of σ1R antagonists both acting alone and in combination with other analgesics have been reported at both central and peripheral sites. At the central level, behavioral, electrophysiological, neurochemical, and molecular findings support a role for σ1R antagonists in inhibiting augmented excitability secondary to sustained afferent input. Moreover, the involvement of σ1R in mechanisms regulating pain at the periphery has been recently confirmed. Unlike opioids, σ1R antagonists do not modify normal sensory mechanical and thermal sensitivity thresholds but they exert antihypersensitivity effects (antihyperalgesic and antiallodynic) in sensitizing conditions, enabling the reversal of nociceptive thresholds back to normal values. These are distinctive features allowing σ1R antagonists to exert a modulatory effect specifically in pathophysiological conditions such as chronic pain.
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Affiliation(s)
- Manuel Merlos
- Drug Discovery and Preclinical Development, ESTEVE, Barcelona, Spain
| | - Luz Romero
- Drug Discovery and Preclinical Development, ESTEVE, Barcelona, Spain
| | - Daniel Zamanillo
- Drug Discovery and Preclinical Development, ESTEVE, Barcelona, Spain
| | | | - José Miguel Vela
- Drug Discovery and Preclinical Development, ESTEVE, Barcelona, Spain.
- Parc Científic de Barcelona, Baldiri Reixac 4-8, 08028, Barcelona, Spain.
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25
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Hiranita T. Identification of the Sigma-2 Receptor: Distinct from the Progesterone Receptor Membrane Component 1 (PGRMC1). ACTA ACUST UNITED AC 2016; 4. [PMID: 27376101 PMCID: PMC4930110 DOI: 10.4172/2329-6488.1000e130] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Takato Hiranita
- Division of Neurotoxicology, National Center for Toxicological Research (NCTR), U.S. Food and Drug Administration (FDA), USA
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26
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Chu UB, Ruoho AE. Biochemical Pharmacology of the Sigma-1 Receptor. Mol Pharmacol 2016; 89:142-53. [PMID: 26560551 DOI: 10.1124/mol.115.101170] [Citation(s) in RCA: 89] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Accepted: 11/06/2015] [Indexed: 12/19/2022] Open
Abstract
The sigma-1 receptor (S1R) is a 223 amino acid two transmembrane (TM) pass protein. It is a non-ATP-binding nonglycosylated ligand-regulated molecular chaperone of unknown three-dimensional structure. The S1R is resident to eukaryotic mitochondrial-associated endoplasmic reticulum and plasma membranes with broad functions that regulate cellular calcium homeostasis and reduce oxidative stress. Several multitasking functions of the S1R are underwritten by chaperone-mediated direct (and indirect) interactions with ion channels, G-protein coupled receptors and cell-signaling molecules involved in the regulation of cell growth. The S1R is a promising drug target for the treatment of several neurodegenerative diseases related to cellular stress. In vitro and in vivo functional and molecular characteristics of the S1R and its interactions with endogenous and synthetic small molecules have been discovered by the use of pharmacologic, biochemical, biophysical, and molecular biology approaches. The S1R exists in monomer, dimer, tetramer, hexamer/octamer, and higher oligomeric forms that may be important determinants in defining the pharmacology and mechanism(s) of action of the S1R. A canonical GXXXG in putative TM2 is important for S1R oligomerization. The ligand-binding regions of S1R have been identified and include portions of TM2 and the TM proximal regions of the C terminus. Some client protein chaperone functions and interactions with the cochaperone 78-kDa glucose-regulated protein (binding immunoglobulin protein) involve the C terminus. Based on its biochemical features and mechanisms of chaperone action the possibility that the S1R is a member of the small heat shock protein family is discussed.
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Affiliation(s)
- Uyen B Chu
- Department of Neuroscience, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin
| | - Arnold E Ruoho
- Department of Neuroscience, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin
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27
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Yasui Y, Su TP. Potential Molecular Mechanisms on the Role of the Sigma-1 Receptor in the Action of Cocaine and Methamphetamine. ACTA ACUST UNITED AC 2016; 5. [PMID: 27088037 DOI: 10.4303/jdar/235970] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The sigma-1 receptor (Sig-1R) is an endoplasmic reticulum membrane protein that involves a wide range of physiological functions. The Sig-1R has been shown to bind psychostimulants including cocaine and methamphetamine (METH) and thus has been implicated in the actions of those psychostimulants. For example, it has been demonstrated that the Sig-1R antagonists mitigate certain behavioral and cellular effects of psychostimulants including hyperactivity and neurotoxicity. Thus, the Sig-1R has become a potential therapeutic target of medication development against drug abuse that differs from traditional monoamine-related strategies. In this review, we will focus on the molecular mechanisms of the Sig-1R and discuss in such a manner with a hope to further understand or unveil unexplored relations between the Sig-1R and the actions of cocaine and METH, particularly in the context of cellular biological relevance.
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Affiliation(s)
- Yuko Yasui
- Cellular Pathobiology Section, Integrative Neuroscience Research Branch, Intramural Research Program, National Institute on Drug Abuse, NIH, DHHS, Baltimore, Maryland 21224
| | - Tsung-Ping Su
- Cellular Pathobiology Section, Integrative Neuroscience Research Branch, Intramural Research Program, National Institute on Drug Abuse, NIH, DHHS, Baltimore, Maryland 21224
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28
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Abstract
Sigma receptors, both Sigma-1(S1R) and Sigma-2 (S2R), are small molecule-regulated, primarily endoplasmic reticulum (ER) membrane-associated sites. A number of drugs bind to sigma receptors, including the antipsychotic haloperidol and (+)-pentazocine, an opioid analgesic. Sigma receptors are implicated in many central nervous system disorders, in particular Alzheimer's disease and conditions associated with motor control, such as Amyotrophic Lateral Sclerosis (ALS). Described in this unit are radioligand binding assays used for the pharmacological characterization of S1R and S2R. Methods detailed include a radioligand saturation binding assay for defining receptor densities and a competitive inhibition binding assay employing [³H]-(+)-pentazocine for identifying and characterizing novel ligands that interact with S1R. Procedures using [³H]-1,3-di(2-tolyl)guanidine ([³H]-DTG), a nonselective sigma receptor ligand, are described for conducting a saturation binding and competitive inhibition assays for the S2R site. These protocols are of value in drug discovery in identifying new sigma ligands and in the characterization of these receptors.
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Affiliation(s)
- Uyen B Chu
- Department of Neuroscience, School of Medicine and Public Health, University of Wisconsin - Madison, Madison, WI, 53706
| | - Arnold E Ruoho
- Department of Neuroscience, School of Medicine and Public Health, University of Wisconsin - Madison, Madison, WI, 53706
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29
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Chu UB, Mavlyutov TA, Chu ML, Yang H, Schulman A, Mesangeau C, McCurdy CR, Guo LW, Ruoho AE. The Sigma-2 Receptor and Progesterone Receptor Membrane Component 1 are Different Binding Sites Derived From Independent Genes. EBioMedicine 2015; 2:1806-13. [PMID: 26870805 PMCID: PMC4740303 DOI: 10.1016/j.ebiom.2015.10.017] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2015] [Revised: 10/07/2015] [Accepted: 10/16/2015] [Indexed: 11/12/2022] Open
Abstract
The sigma-2 receptor (S2R) is a potential therapeutic target for cancer and neuronal diseases. However, the identity of the S2R has remained a matter of debate. Historically, the S2R has been defined as (1) a binding site with high affinity to 1,3-di-o-tolylguanidine (DTG) and haloperidol but not to the selective sigma-1 receptor ligand (+)-pentazocine, and (2) a protein of 18–21 kDa, as shown by specific photolabeling with [3H]-Azido-DTG and [125I]-iodoazido-fenpropimorph ([125I]-IAF). Recently, the progesterone receptor membrane component 1 (PGRMC1), a 25 kDa protein, was reported to be the S2R (Nature Communications, 2011, 2:380). To confirm this identification, we created PGRMC1 knockout NSC34 cell lines using the CRISPR/Cas9 technology. We found that in NSC34 cells devoid of or overexpressing PGRMC1, the maximum [3H]-DTG binding to the S2R (Bmax) as well as the DTG-protectable [125I]-IAF photolabeling of the S2R were similar to those of wild-type control cells. Furthermore, the affinities of DTG and haloperidol for PGRMC1 (KI = 472 μM and 350 μM, respectively), as determined in competition with [3H]-progesterone, were more than 3 orders of magnitude lower than those reported for the S2R (20–80 nM). These results clarify that PGRMC1 and the S2R are distinct binding sites expressed by different genes. The sigma-2 receptor is an important drug target but its molecular identity has remained a hot topic of debate. PGRMC1 has recently been reported to be the sigma-2 binding site (Nature Communications, 2011, 2:380). Our data clarify that PGRMC1 and the sigma-2 receptor are distinct binding sites expressed by different genes.
The sigma-2 receptor (S2R) is a potential important therapeutic target for cancer and neuronal diseases, yet its gene identity is a long-held mystery. While a recent prominent report concluded that a progesterone-binding protein (PGRMC1) is the sigma-2 receptor, the critical defining evidence was missing. We re-tested this conclusion using a genome-editing technology combined with chemical biology and pharmacological determinations. The unambiguous results indicate that PGRMC1 is not the originally defined true sigma-2 receptor. This study may benefit public health by guiding future discovery of the true identity of the sigma-2 drug binding site.
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Affiliation(s)
- Uyen B Chu
- Department of Neuroscience, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States
| | - Timur A Mavlyutov
- Department of Surgery, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States
| | - Ming-Liang Chu
- Department of Surgery, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States
| | - Huan Yang
- Department of Surgery, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States
| | - Amanda Schulman
- Department of Neuroscience, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States
| | - Christophe Mesangeau
- Department of BioMolecular Sciences, School of Pharmacy, University of Mississippi, United States
| | - Christopher R McCurdy
- Department of BioMolecular Sciences, School of Pharmacy, University of Mississippi, United States
| | - Lian-Wang Guo
- Department of Surgery, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States; McPherson Eye Research Institute, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States
| | - Arnold E Ruoho
- Department of Neuroscience, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States
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30
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Mishra AK, Mavlyutov T, Singh DR, Biener G, Yang J, Oliver JA, Ruoho A, Raicu V. The sigma-1 receptors are present in monomeric and oligomeric forms in living cells in the presence and absence of ligands. Biochem J 2015; 466:263-271. [PMID: 25510962 PMCID: PMC4500508 DOI: 10.1042/bj20141321] [Citation(s) in RCA: 86] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The sigma-1 receptor (S1R) is a 223-amino-acid membrane protein that resides in the endoplasmic reticulum and the plasma membrane of some mammalian cells. The S1R is regulated by various synthetic molecules including (+)-pentazocine, cocaine and haloperidol and endogenous molecules such as sphingosine, dimethyltryptamine and dehydroepiandrosterone. Ligand-regulated protein chaperone functions linked to oxidative stress and neurodegenerative disorders such as amyotrophic lateral sclerosis (ALS) and neuropathic pain have been attributed to the S1R. Several client proteins that interact with S1R have been identified including various types of ion channels and G-protein coupled receptors (GPCRs). When S1R constructs containing C-terminal monomeric GFP2 and YFP fusions were co-expressed in COS-7 cells and subjected to FRET spectrometry analysis, monomers, dimers and higher oligomeric forms of S1R were identified under non-liganded conditions. In the presence of the prototypic S1R agonist, (+)-pentazocine, however, monomers and dimers were the prevailing forms of S1R. The prototypic antagonist, haloperidol, on the other hand, favoured higher order S1R oligomers. These data, in sum, indicate that heterologously expressed S1Rs occur in vivo in COS-7 cells in multiple oligomeric forms and that S1R ligands alter these oligomeric structures. We suggest that the S1R oligomerization states may regulate its function(s).
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Affiliation(s)
- Ashish K. Mishra
- Physics Department, University of Wisconsin-Milwaukee, Milwaukee, WI 53211, U.S.A
| | - Timur Mavlyutov
- Department of Neuroscience, University of Wisconsin-Madison, Madison, WI 53211, U.S.A
| | - Deo R. Singh
- Physics Department, University of Wisconsin-Milwaukee, Milwaukee, WI 53211, U.S.A
| | - Gabriel Biener
- Physics Department, University of Wisconsin-Milwaukee, Milwaukee, WI 53211, U.S.A
| | - Jay Yang
- Department of Anesthesiology, University of Wisconsin-Madison, Madison, WI 53211, U.S.A
| | - Julie A. Oliver
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI 53211, U.S.A
| | - Arnold Ruoho
- Department of Neuroscience, University of Wisconsin-Madison, Madison, WI 53211, U.S.A
| | - Valerică Raicu
- Physics Department, University of Wisconsin-Milwaukee, Milwaukee, WI 53211, U.S.A
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI 53211, U.S.A
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31
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Ortega-Roldan JL, Ossa F, Amin NT, Schnell JR. Solution NMR studies reveal the location of the second transmembrane domain of the human sigma-1 receptor. FEBS Lett 2015; 589:659-65. [PMID: 25647032 PMCID: PMC4332692 DOI: 10.1016/j.febslet.2015.01.033] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2014] [Revised: 01/19/2015] [Accepted: 01/22/2015] [Indexed: 11/26/2022]
Abstract
The sigma-1 receptor (S1R) is a ligand-regulated membrane chaperone protein associated with endoplasmic reticulum stress response, and modulation of ion channel activities at the plasma membrane. We report here a solution NMR study of a S1R construct (S1R(Δ35)) in which only the first transmembrane domain and the eight-residue N-terminus have been removed. The second transmembrane helix is found to be composed of residues 91-107, which corresponds to the first steroid binding domain-like region. The cytosolic domain is found to contain three helices, and the secondary structure and backbone dynamics of the chaperone domain are consistent with that determined previously for the chaperone domain alone. The position of TM2 provides a framework for ongoing studies of S1R ligand binding and oligomerisation.
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Affiliation(s)
| | - Felipe Ossa
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Nader T Amin
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Jason R Schnell
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK.
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32
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Hajipour AR, Khorsandi Z, Mortazavi M, Farrokhpour H. Green, efficient and large-scale synthesis of benzimidazoles, benzoxazoles and benzothiazoles derivatives using ligand-free cobalt-nanoparticles: as potential anti-estrogen breast cancer agents, and study of their interactions with estrogen receptor by molecular docking. RSC Adv 2015. [DOI: 10.1039/c5ra22207a] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
A facile and high yielding method for the synthesis of 2-aryl benzoxazoles, benzimidazole and benzothiazoles is reported employing cobalt oxide nanoparticles.
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Affiliation(s)
- Abdol R. Hajipour
- Pharmaceutical Research Laboratory
- Department of Chemistry
- Isfahan University of Technology
- Isfahan 84156
- Islamic Republic of Iran
| | - Zahra Khorsandi
- Pharmaceutical Research Laboratory
- Department of Chemistry
- Isfahan University of Technology
- Isfahan 84156
- Islamic Republic of Iran
| | - Maryam Mortazavi
- Department of Chemistry
- Isfahan University of Technology
- Isfahan
- I. R. Iran
- Department of Chemistry
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33
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Manohar M, Banister SD, Beinat C, O'Brien-Brown J, Kassiou M. Recent Advances in the Development of Sigma-1 Receptor Ligands. Aust J Chem 2015. [DOI: 10.1071/ch14590] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The existence of two distinct sigma (σ) receptor subtypes was established in the early 1990s. Sigma-1 and sigma-2 receptors (S1Rs and S2Rs, respectively) were shown to possess distinct molecular size, anatomical distribution, and ligand discrimination. S2R is overexpressed in numerous human cancers, and has therapeutic potential for the imaging and treatment of certain tumours. In contrast, S1R is more broadly involved in a wide variety of central nervous system (CNS) diseases including motor disorders, memory deficits, depression, schizophrenia, anxiety, pain, drug addiction, and many more. Since the human S1R was cloned in 1996, numerous high affinity ligands with excellent selectivity for S1R have been developed. This review focuses on recent developments in the generation of structurally diverse S1R-selective ligands and novel therapeutic candidates targeting S1Rs.
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34
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Gromek KA, Suchy FP, Meddaugh HR, Wrobel RL, LaPointe LM, Chu UB, Primm JG, Ruoho AE, Senes A, Fox BG. The oligomeric states of the purified sigma-1 receptor are stabilized by ligands. J Biol Chem 2014; 289:20333-44. [PMID: 24847081 PMCID: PMC4106346 DOI: 10.1074/jbc.m113.537993] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2013] [Revised: 04/29/2014] [Indexed: 12/05/2022] Open
Abstract
Sigma-1 receptor (S1R) is a mammalian member of the ERG2 and sigma-1 receptor-like protein family (pfam04622). It has been implicated in drug addiction and many human neurological disorders, including Alzheimer and Parkinson diseases and amyotrophic lateral sclerosis. A broad range of synthetic small molecules, including cocaine, (+)-pentazocine, haloperidol, and small endogenous molecules such as N,N-dimethyltryptamine, sphingosine, and steroids, have been identified as regulators of S1R. However, the mechanism of activation of S1R remains obscure. Here, we provide evidence in vitro that S1R has ligand binding activity only in an oligomeric state. The oligomeric state is prone to decay into an apparent monomeric form when exposed to elevated temperature, with loss of ligand binding activity. This decay is suppressed in the presence of the known S1R ligands such as haloperidol, BD-1047, and sphingosine. S1R has a GXXXG motif in its second transmembrane region, and these motifs are often involved in oligomerization of membrane proteins. Disrupting mutations within the GXXXG motif shifted the fraction of the higher oligomeric states toward smaller states and resulted in a significant decrease in specific (+)-[(3)H]pentazocine binding. Results presented here support the proposal that S1R function may be regulated by its oligomeric state. Possible mechanisms of molecular regulation of interacting protein partners by S1R in the presence of small molecule ligands are discussed.
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Affiliation(s)
| | | | | | | | | | - Uyen B Chu
- Neuroscience, University of Wisconsin-Madison, Madison, Wisconsin 53706
| | | | - Arnold E Ruoho
- Neuroscience, University of Wisconsin-Madison, Madison, Wisconsin 53706
| | | | - Brian G Fox
- From the Transmembrane Protein Center, Departments of Biochemistry and
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35
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Abstract
The exact 3D structure of the enigmatic σ1 receptor is unknown, as the crystal structure of this protein has not been solved so far. Many efforts have been devoted to unveiling the structure of the σ1 receptor and specifically its binding site, which include photoaffinity labeling, site directed mutagenesis, and homology modeling. The aim of the present miniperspective is to give a short overview of all results that contribute to the current knowledge of the σ1 receptor and its ligand binding site.
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Affiliation(s)
- Stefanie Brune
- Institut für Pharmazeutische und Medizinische Chemie der Westfälischen Wilhelms-Universität Münster , Corrensstraße 48, D-48149 Münster, Germany
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36
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Holl K, Falck E, Köhler J, Schepmann D, Humpf HU, Brust P, Wünsch B. Synthesis, Characterization, and Metabolism Studies of Fluspidine Enantiomers. ChemMedChem 2013; 8:2047-56. [DOI: 10.1002/cmdc.201300322] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Revised: 09/03/2013] [Indexed: 11/12/2022]
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37
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Ortega-Roldan JL, Ossa F, Schnell JR. Characterization of the human sigma-1 receptor chaperone domain structure and binding immunoglobulin protein (BiP) interactions. J Biol Chem 2013; 288:21448-21457. [PMID: 23760505 PMCID: PMC3774411 DOI: 10.1074/jbc.m113.450379] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2013] [Revised: 05/31/2013] [Indexed: 01/09/2023] Open
Abstract
The sigma-1 receptor (S1R) is a ligand-regulated membrane protein chaperone involved in the ER stress response. S1R activity is implicated in diseases of the central nervous system including amnesia, schizophrenia, depression, Alzheimer disease, and addiction. S1R has been shown previously to regulate the Hsp70 binding immunoglobulin protein (BiP) and the inositol triphosphate receptor calcium channel through a C-terminal domain. We have developed methods for bacterial expression and reconstitution of the chaperone domain of human S1R into detergent micelles that enable its study by solution NMR spectroscopy. The chaperone domain is found to contain a helix at the N terminus followed by a largely dynamic region and a structured, helical C-terminal region that encompasses a membrane associated domain containing four helices. The helical region at residues ∼198-206 is strongly amphipathic and proposed to anchor the chaperone domain to micelles and membranes. Three of the helices in the C-terminal region closely correspond to previously identified cholesterol and drug recognition sites. In addition, it is shown that the chaperone domain interacts with full-length BiP or the isolated nucleotide binding domain of BiP, but not the substrate binding domain, suggesting that the nucleotide binding domain is sufficient for S1R interactions.
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Affiliation(s)
| | - Felipe Ossa
- From the Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom
| | - Jason R Schnell
- From the Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom.
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38
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Rossi D, Pedrali A, Gaggeri R, Marra A, Pignataro L, Laurini E, Dal Col V, Fermeglia M, Pricl S, Schepmann D, Wünsch B, Peviani M, Curti D, Collina S. Chemical, Pharmacological, and in vitro Metabolic Stability Studies on Enantiomerically Pure RC‐33 Compounds: Promising Neuroprotective Agents Acting as σ
1
Receptor Agonists. ChemMedChem 2013; 8:1514-27. [DOI: 10.1002/cmdc.201300218] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Indexed: 12/22/2022]
Affiliation(s)
- Daniela Rossi
- Department of Drug Sciences, Medicinal Chemistry and Pharmaceutical Technology Section, University of Pavia, Viale Taramelli 12, 27100 Pavia (Italy)
| | - Alice Pedrali
- Department of Drug Sciences, Medicinal Chemistry and Pharmaceutical Technology Section, University of Pavia, Viale Taramelli 12, 27100 Pavia (Italy)
| | - Raffaella Gaggeri
- Department of Drug Sciences, Medicinal Chemistry and Pharmaceutical Technology Section, University of Pavia, Viale Taramelli 12, 27100 Pavia (Italy)
| | - Annamaria Marra
- Department of Drug Sciences, Medicinal Chemistry and Pharmaceutical Technology Section, University of Pavia, Viale Taramelli 12, 27100 Pavia (Italy)
| | - Luca Pignataro
- Dipartimento di Chimica, Università degli Studi di Milano, Istituto di Scienze e Tecnologie Molecolari (ISTM) del CNR, Via Golgi 19, 20133 Milan (Italy)
| | - Erik Laurini
- MOSE‐DEA, University of Trieste, Via Valerio 10, 34127 Trieste (Italy)
| | - Valentina Dal Col
- MOSE‐DEA, University of Trieste, Via Valerio 10, 34127 Trieste (Italy)
| | | | - Sabrina Pricl
- MOSE‐DEA, University of Trieste, Via Valerio 10, 34127 Trieste (Italy)
- National Interuniversity Consortium for Material Science and Technology (INSTM), Research Unit MOSE‐DEA, University of Trieste, Trieste (Italy)
| | - Dirk Schepmann
- Institute of Pharmaceutical and Medicinal Chemistry, University of Muenster, Correnstrasse 48, 48149 Münster (Germany)
| | - Bernhard Wünsch
- Institute of Pharmaceutical and Medicinal Chemistry, University of Muenster, Correnstrasse 48, 48149 Münster (Germany)
| | - Marco Peviani
- Department of Biology and Biotechnology “L. Spallanzani”, Laboratory of Cellular and Molecular Neuropharmacology, University of Pavia, Via Ferrata 9, 27100 Pavia (Italy)
| | - Daniela Curti
- Department of Biology and Biotechnology “L. Spallanzani”, Laboratory of Cellular and Molecular Neuropharmacology, University of Pavia, Via Ferrata 9, 27100 Pavia (Italy)
| | - Simona Collina
- Department of Drug Sciences, Medicinal Chemistry and Pharmaceutical Technology Section, University of Pavia, Viale Taramelli 12, 27100 Pavia (Italy)
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Moriguchi S, Shinoda Y, Yamamoto Y, Sasaki Y, Miyajima K, Tagashira H, Fukunaga K. Stimulation of the sigma-1 receptor by DHEA enhances synaptic efficacy and neurogenesis in the hippocampal dentate gyrus of olfactory bulbectomized mice. PLoS One 2013; 8:e60863. [PMID: 23593332 PMCID: PMC3620380 DOI: 10.1371/journal.pone.0060863] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2013] [Accepted: 03/04/2013] [Indexed: 11/18/2022] Open
Abstract
Dehydroepiandrosterone (DHEA) is the most abundant neurosteroid synthesized de novo in the central nervous system. We previously reported that stimulation of the sigma-1 receptor by DHEA improves cognitive function by activating calcium/calmodulin-dependent protein kinase II (CaMKII), protein kinase C and extracellular signal-regulated kinase in the hippocampus in olfactory bulbectomized (OBX) mice. Here, we asked whether DHEA enhances neurogenesis in the subgranular zone of the hippocampal dentate gyrus (DG) and improves depressive-like behaviors observed in OBX mice. Chronic treatment with DHEA at 30 or 60 mg/kg p.o. for 14 days significantly improved hippocampal LTP impaired in OBX mice concomitant with increased CaMKII autophosphorylation and GluR1 (Ser-831) phosphorylation in the DG. Chronic DHEA treatment also ameliorated depressive-like behaviors in OBX mice, as assessed by tail suspension and forced swim tests, while a single DHEA treatment had no affect. DHEA treatment also significantly increased the number of BrdU-positive neurons in the subgranular zone of the DG of OBX mice, an increase inhibited by treatment with NE-100, a sigma-1 receptor antagonist. DHEA treatment also significantly increased phosphorylation of Akt (Ser-473), Akt (Ser-308) and ERK in the DG. Furthermore, GSK-3β (Ser-9) phosphorylation increased in the DG of OBX mice possibly accounting for increased neurogenesis through Akt activation. Finally, we confirmed that DHEA treatment of OBX mice increases the number of BrdU-positive neurons co-expressing β-catenin, a downstream GSK-3βtarget. Overall, we conclude that sigma-1 receptor stimulation by DHEA ameliorates OBX-induced depressive-like behaviors by increasing neurogenesis in the DG through activation of the Akt/GSK-3β/β-catenin pathway.
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Affiliation(s)
- Shigeki Moriguchi
- Department of Pharmacology, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan
| | - Yasuharu Shinoda
- Department of Pharmacology, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan
| | - Yui Yamamoto
- Department of Pharmacology, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan
| | - Yuzuru Sasaki
- Department of Pharmacology, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan
| | - Kosuke Miyajima
- Department of Pharmacology, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan
| | - Hideaki Tagashira
- Department of Pharmacology, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan
| | - Kohji Fukunaga
- Department of Pharmacology, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan
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40
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Guo L, Zhao J, Jin G, Zhao B, Wang G, Zhang A, Zhen X. SKF83959 is a potent allosteric modulator of sigma-1 receptor. Mol Pharmacol 2013; 83:577-86. [PMID: 23295385 DOI: 10.1124/mol.112.083840] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
SKF83959 (3-methyl-6-chloro-7,8-hydroxy-1-[3-methylphenyl]-2,3,4,5-tetrahydro-1H-3-benzazepine), an atypical dopamine receptor-1 (D(1) receptor) agonist, has shown many D(1) receptor-independent effects, such as neuroprotection, blockade of Na(+) channel, and promotion of spontaneous glutamate release, which resemble the effects of the sigma-1 receptor activation. In the present work, we explored the potential modulation of SKF83959 on the sigma-1 receptor. The results indicated that SKF83959 dramatically promoted the binding of (3)H(+)-pentazocine (a selective sigma-1 receptor agonist) to the sigma-1 receptor in brain and liver tissues but produced no effect on (3)H-progesterone binding (a sigma-1 receptor antagonist). The saturation assay and the dissociation kinetics assay confirmed the allosteric effect. We further demonstrated that the SKF83959 analogs, such as SCH22390 [(R)-(1)-7-chloro-8- hydroxy-3-methyl-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine hydrochloride] and SKF38393 [(+/-)-1-phenyl-2,3,4,5-tetrahydro-(1H)-3-benzazepine-7,8-diol hydrobromide], also showed the similar allosteric effect on the sigma-1 receptor in the liver tissue but not in the brain tissue. Moreover, all three tested chemicals elicited no significant effect on (3)H-1,3-di(2-tolyl)-guanidine ((3)H-DTG) binding to the sigma-2 receptor. The present data uncovered a new role of SKF83959 and its analogs on the sigma-1 receptor, which, in turn, may reveal the underlying mechanism for the D(1) receptor-independent effect of the drug.
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MESH Headings
- 2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine/analogs & derivatives
- 2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine/pharmacology
- Allosteric Regulation/drug effects
- Animals
- Brain/drug effects
- Brain/metabolism
- Cell Line
- Drug Synergism
- HEK293 Cells
- Humans
- Liver/drug effects
- Liver/metabolism
- Male
- Pentazocine/pharmacology
- Progesterone/metabolism
- Rats
- Rats, Sprague-Dawley
- Receptors, Dopamine D1/agonists
- Receptors, Dopamine D1/metabolism
- Receptors, sigma/agonists
- Receptors, sigma/antagonists & inhibitors
- Receptors, sigma/metabolism
- Sigma-1 Receptor
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Affiliation(s)
- Lin Guo
- Department of Pharmacology II, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
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41
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Chu UB, Ramachandran S, Hajipour AR, Ruoho AE. Photoaffinity labeling of the sigma-1 receptor with N-[3-(4-nitrophenyl)propyl]-N-dodecylamine: evidence of receptor dimers. Biochemistry 2013; 52:859-68. [PMID: 23324054 PMCID: PMC3581363 DOI: 10.1021/bi301517u] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The sigma-1 receptor is a ligand-regulated endoplasmic reticulum (ER) resident chaperone involved in the maintenance of cellular homeostasis. Coupling of the sigma-1 receptor with various ER and/or plasma membrane ion channels is associated with its ability to regulate the locomotor activity and cellular proliferation produced in response to sigma-1 receptor ligands. A number of endogenous small molecules bind to the sigma-1 receptor and have been shown to regulate its activity; these include progesterone, N,N-dimethyltryptamine, d-erythro-sphingosine, and/or other endogenous lipids. We previously reported the synthesis of long chain N-alkylamine derivatives and the characterization of the structure-activity relationship between the chain length of N-alkylamine and affinities at the sigma-1 receptor. Here, we present data demonstrating the photoincorporation of one of these N-alkylamine derivatives, N-[3-(4-nitrophenyl)propyl]-N-dodecylamine (4-NPPC12), to the sigma-1 receptor. Matrix-assisted laser desorption ionization time-of-flight and tandem mass spectrometry showed that 4-NPPC12 photoinserted at histidine 154 of the derivatized population of the sigma-1 receptor. Interestingly, light-dependent photoinsertion of 4-NPPC12 resulted in an enhanced electrophoretic mobility of only 50% of the derivatized receptor molecules as assessed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The proposed binding and reactivity of 4-NPPC12 evoke a ligand binding model for the sigma-1 receptor that likely involves a receptor dimer and/or oligomer.
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Affiliation(s)
- Uyen B. Chu
- Department of Neuroscience, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53706
| | - Subramaniam Ramachandran
- Department of Neuroscience, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53706
| | - Abdol R. Hajipour
- Pharmaceutical Research Laboratory, College of Chemistry, Isfahan University of Technology, Isfahan 84156, IR Iran
| | - Arnold E. Ruoho
- Department of Neuroscience, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53706
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42
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Hayashi T, Hayashi E, Fujimoto M, Sprong H, Su TP. The lifetime of UDP-galactose:ceramide galactosyltransferase is controlled by a distinct endoplasmic reticulum-associated degradation (ERAD) regulated by sigma-1 receptor chaperones. J Biol Chem 2012; 287:43156-69. [PMID: 23105111 PMCID: PMC3522309 DOI: 10.1074/jbc.m112.380444] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2012] [Revised: 10/20/2012] [Indexed: 11/06/2022] Open
Abstract
The glycosphingolipid biosynthesis is initiated by monoglycosylation of ceramides, the action of which is catalyzed either by UDP-glucose:ceramide glucosyltransferase or by UDP-galactose:ceramide galactosyltransferase (CGalT). CGalT is expressed predominantly at the endoplasmic reticulum (ER) of oligodendrocytes and is responsible for synthesizing galactosylceramides (GalCer) that play an important role in regulation of axon conductance. However, despite the importance of ceramide monoglycosylation enzymes in a spectrum of cellular functions, the mechanism that fine tunes activities of those enzymes is largely unknown. In the present study, we demonstrated that the sigma-1 receptor (Sig-1R) chaperone, the mammalian homologue of a yeast C8-C7 sterol isomerase, controls the protein level and activity of the CGalT enzyme via a distinct ER-associated degradation system involving Insig. The Sig-1R forms a complex with Insig via its transmembrane domain partly in a sterol-dependent manner and associates with CGalT at the ER. The knockdown of Sig-1Rs dramatically prolonged the lifetime of CGalT without affecting the trimming of N-linked oligosaccharides at CGalT. The increased lifetime leads to the up-regulation of CGalT protein as well as elevated enzymatic activity in CHO cells stably expressing CGalT. Knockdown of Sig-1Rs also decreased CGalT degradation endogenously expressed in D6P2T-schwannoma cells. Our data suggest that Sig-1Rs negatively regulate the activity of GalCer synthesis under physiological conditions by enhancing the degradation of CGalT through regulation of the dynamics of Insig in the lipid-activated ER-associated degradation system. The GalCer synthesis may thus be influenced by sterols at the ER.
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Affiliation(s)
| | | | | | - Hein Sprong
- the National Institute of Public Health and Environment, Laboratory for Zoonoses and Environmental Microbiology, Bilthoven, Netherlands
| | - Tsung-Ping Su
- the Cellular Pathobiology Section, Integrative Neuroscience Branch, Intramural Research Program, NIDA, National Institutes of Health, Baltimore, Maryland 21224 and
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Balasuriya D, Stewart AP, Crottès D, Borgese F, Soriani O, Edwardson JM. The sigma-1 receptor binds to the Nav1.5 voltage-gated Na+ channel with 4-fold symmetry. J Biol Chem 2012; 287:37021-9. [PMID: 22952230 PMCID: PMC3481303 DOI: 10.1074/jbc.m112.382077] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2012] [Revised: 08/20/2012] [Indexed: 12/19/2022] Open
Abstract
The sigma-1 receptor (Sig1R) is up-regulated in many human tumors and plays a role in the control of cancer cell proliferation and invasiveness. At the molecular level, the Sig1R modulates the activity of various ion channels, apparently through a direct interaction. We have previously shown using atomic force microscopy imaging that the Sig1R binds to the trimeric acid-sensing ion channel 1A with 3-fold symmetry. Here, we investigated the interaction between the Sig1R and the Nav1.5 voltage-gated Na(+) channel, which has also been implicated in promoting the invasiveness of cancer cells. We show that the Sig1R and Nav1.5 can be co-isolated from co-transfected cells, consistent with an intimate association between the two proteins. Atomic force microscopy imaging of the co-isolated proteins revealed complexes in which Nav1.5 was decorated by Sig1Rs. Frequency distributions of angles between pairs of bound Sig1Rs had two peaks, at ∼90° and ∼180°, and the 90° peak was about twice the size of the 180° peak. These results demonstrate that the Sig1R binds to Nav1.5 with 4-fold symmetry. Hence, each set of six transmembrane regions in Nav1.5 likely constitutes a Sig1R binding site, suggesting that the Sig1R interacts with the transmembrane regions of its partners. Interestingly, two known Sig1R ligands, haloperidol and (+)-pentazocine, disrupted the Nav1.5/Sig1R interaction both in vitro and in living cells. Finally, we show that endogenously expressed Sig1R and Nav1.5 also functionally interact.
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Affiliation(s)
- Dilshan Balasuriya
- From the Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, United Kingdom and
| | - Andrew P. Stewart
- From the Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, United Kingdom and
| | - David Crottès
- Institut de Biologie de Valrose, CNRS UMR 7277, INSERM U1091 UNS, Faculté des Sciences, Université de Nice Sophia Antipolis, 06108 Nice Cedex 2, France
| | - Franck Borgese
- Institut de Biologie de Valrose, CNRS UMR 7277, INSERM U1091 UNS, Faculté des Sciences, Université de Nice Sophia Antipolis, 06108 Nice Cedex 2, France
| | - Olivier Soriani
- Institut de Biologie de Valrose, CNRS UMR 7277, INSERM U1091 UNS, Faculté des Sciences, Université de Nice Sophia Antipolis, 06108 Nice Cedex 2, France
| | - J. Michael Edwardson
- From the Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, United Kingdom and
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44
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Behensky AA, Cortes-Salva M, Seminerio MJ, Matsumoto RR, Antilla JC, Cuevas J. In vitro evaluation of guanidine analogs as sigma receptor ligands for potential anti-stroke therapeutics. J Pharmacol Exp Ther 2012; 344:155-66. [PMID: 23065135 DOI: 10.1124/jpet.112.199513] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Currently, the only Food and Drug Administration-approved treatment of acute stroke is recombinant tissue plasminogen activator, which must be administered within 6 hours after stroke onset. The pan-selective σ-receptor agonist N,N'-di-o-tolyl-guanidine (o-DTG) has been shown to reduce infarct volume in rats after middle cerebral artery occlusion, even when administered 24 hours after stroke. DTG derivatives were synthesized to develop novel compounds with greater potency than o-DTG. Fluorometric Ca(2+) imaging was used in cultured cortical neurons to screen compounds for their capacity to reduce ischemia- and acidosis-evoked cytosolic Ca(2+) overload, which has been linked to stroke-induced neurodegeneration. In both assays, migration of the methyl moiety produced no significant differences, but removal of the group increased potency of the compound for inhibiting acidosis-induced [Ca(2+)](i) elevations. Chloro and bromo substitution of the methyl moiety in the meta and para positions increased potency by ≤160%, but fluoro substitutions had no effect. The most potent DTG derivative tested was N,N'-di-p-bromo-phenyl-guanidine (p-BrDPhG), which had an IC(50) of 2.2 µM in the ischemia assay, compared with 74.7 μM for o-DTG. Microglial migration assays also showed that p-BrDPhG is more potent than o-DTG in this marker for microglial activation, which is also linked to neuronal injury after stroke. Radioligand binding studies showed that p-BrDPhG is a pan-selective σ ligand. Experiments using the σ-1 receptor-selective antagonist 1-[2-(3,4-dichlorophenyl)ethyl]-4-methylpiperazine dihydrochloride (BD-1063) demonstrated that p-BrDPhG blocks Ca(2+) overload via σ-1 receptor activation. The study identified four compounds that may be more effective than o-DTG for the treatment of ischemic stroke at delayed time points.
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Affiliation(s)
- Adam A Behensky
- Department of Molecular Pharmacology and Physiology, University of South Florida College of Medicine, 12901 Bruce B. Downs Blvd., MDC-9, Tampa, FL 33612-4799, USA
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45
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Laurini E, Marson D, Dal Col V, Fermeglia M, Mamolo MG, Zampieri D, Vio L, Pricl S. Another brick in the wall. Validation of the σ1 receptor 3D model by computer-assisted design, synthesis, and activity of new σ1 ligands. Mol Pharm 2012; 9:3107-26. [PMID: 23020867 DOI: 10.1021/mp300233y] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Originally considered an enigmatic polypeptide, the σ(1) receptor has recently been identified as a unique ligand-regulated protein. Many studies have shown the potential of σ(1) receptor ligands for the treatment of various diseases of the central nervous system (CNS); nevertheless, almost no information about the 3D structure of the receptor and/or the possible modes of interaction of the σ(1) protein with its ligands have been unveiled so far. With the present work we validated our σ(1) 3D homology model and assessed its reliability as a platform for σ(1) ligand structure-based drug design. To this purpose, the 3D σ(1) model was exploited in the design of 33 new σ(1) ligands and in their ranking for receptor affinity by extensive molecular dynamics simulation-based free energy calculations. Also, the main interactions involved in receptor/ligand binding were analyzed by applying a per residue free energy deconvolution and in silico alanine scanning mutagenesis calculations. Subsequently, all compounds were synthesized in our laboratory and tested for σ(1) binding activity in vitro. The agreement between in silico and in vitro results confirms the reliability of the proposed σ(1) 3D model in the a priori prediction of the affinity of new σ(1) ligands. Moreover, it also supports and corroborates the currently available biochemical data concerning the σ(1) protein residues considered essential for σ(1) ligand binding and activity.
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Affiliation(s)
- Erik Laurini
- Molecular Simulation Engineering Laboratory, Department of Industrial Engineering and Information Technology, University of Trieste, Via Valerio 10, 34127 Trieste, Italy
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Meyer C, Schepmann D, Yanagisawa S, Yamaguchi J, Dal Col V, Laurini E, Itami K, Pricl S, Wünsch B. Pd-catalyzed direct C-H bond functionalization of spirocyclic σ1 ligands: generation of a pharmacophore model and analysis of the reverse binding mode by docking into a 3D homology model of the σ1 receptor. J Med Chem 2012; 55:8047-65. [PMID: 22913577 DOI: 10.1021/jm300894h] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
To explore the hydrophobic binding region of the σ(1) receptor protein, regioisomeric spirocyclic thiophenes 9-11 were developed as versatile building blocks. Regioselective α- and β-arylation using the catalyst systems PdCl(2)/bipy/Ag(2)CO(3) and PdCl(2)/P[OCH(CF(3))(2)](3)/Ag(2)CO(3) allowed the introduction of various aryl moieties at different positions in the last step of the synthesis. The increasing σ(1) affinity in the order 4 < 5/6 < 7/8 indicates that the positions of the additional aryl moiety and the S atom in the spirocyclic thiophene systems control the σ(1) affinity. The main features of the pharmacophore model developed for this class of σ(1) ligands are a positive ionizable group, a H-bond acceptor group, two hydrophobic moieties, and one hydrophobic aromatic group. Docking of the ligands into a σ(1) 3D homology model via molecular mechanics/Poisson-Boltzmann surface area calculations led to a very good correlation between the experimentally determined and estimated free energy of receptor binding. These calculations support the hypothesis of a reverse binding mode of ligands bearing the aryl moiety at the "top" (compounds 2, 3, 7, and 8) and "left" (compounds 4, 5, and 6) positions, respectively.
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Affiliation(s)
- Christina Meyer
- Institut für Pharmazeutische und Medizinische Chemie der Westfälischen Wilhelms-Universität Münster, Hittorfstrasse 58-62, D-48149 Münster, Germany
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47
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Guo LW, Hajipour AR, Karaoglu K, Mavlyutov TA, Ruoho AE. Development of benzophenone-alkyne bifunctional sigma receptor ligands. Chembiochem 2012; 13:2277-89. [PMID: 23001760 DOI: 10.1002/cbic.201200427] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2012] [Indexed: 12/12/2022]
Abstract
Sigma (σ) receptors are unique non-opioid binding sites that are associated with a broad range of disease states. Sigma-2 receptors provide a promising target for diagnostic imaging and pharmacological interventions to curb tumor progression. Most recently, the progesterone receptor (PGRMC1, 25 kDa) has been shown to have σ2 receptor-like binding properties, thus highlighting the need to understand the biological function of an 18 kDa protein that exhibits σ2-like photoaffinity labeling (denoted here as σ2-18k) but the amino acid sequence of which is not known. In order to provide new tools for the study of the σ2-18k protein, we have developed bifunctional σ receptor ligands each bearing a benzophenone photo-crosslinking moiety and an alkyne group to which an azide-containing biotin affinity tag can be covalently attached through click chemistry after photo-crosslinking. Although several compounds showed favorable σ2 binding properties, the highest affinity (2 nM) and the greatest potency in blocking photolabeling of σ2-18k by a radioactive photoaffinity ligand was shown by compound 22. These benzophenone-alkyne σ receptor ligands might therefore be amenable for studying the σ2-18k protein through chemical biology approaches. To the best of our knowledge, these compounds represent the first reported benzophenone-containing clickable σ receptor ligands, which might potentially have broad applications based on the "plugging in" of various tags.
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Affiliation(s)
- Lian-Wang Guo
- Department of Neuroscience, University of Wisconsin School of Medicine and Public Health, 1300 University Ave., Madison, WI 53706, USA
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He YL, Zhang CL, Gao XF, Yao JJ, Hu CL, Mei YA. Cyproheptadine enhances the I(K) of mouse cortical neurons through sigma-1 receptor-mediated intracellular signal pathway. PLoS One 2012; 7:e41303. [PMID: 22844454 PMCID: PMC3402501 DOI: 10.1371/journal.pone.0041303] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2012] [Accepted: 06/19/2012] [Indexed: 11/18/2022] Open
Abstract
Cyproheptadine (CPH) is a histamine- and serotonin-receptor antagonist, and its effects are observed recently in the modulation of multiple intracellular signals. In this study, we used cortical neurons and HEK-293 cells transfected with Kv2.1 α-subunit to address whether CPH modify neural voltage-gated K(+) channels by a mechanism independent of its serotonergic and histaminergic properties. Our results demonstrate that intracellularly delivered CPH increased the I(K) by reducing the activity of protein kinas A (PKA). Inhibition of G(i) eliminated the CPH-induced effect on both the I(K) and PKA. Blocking of 5-HT-, M-, D(2)-, H(1)- or H(2)-type GPCR receptors with relevant antagonists did not eliminate the CPH-induced effect on the I(K). Antagonists of the sigma-1 receptor, however, blocked the effect of CPH. Moreover, the inhibition of sigma-1 by siRNA knockdown significantly reduced the CPH-induced effect on the I(K). On the contrary, sigma-1 receptor agonist mimicked the effects of CPH on the induction of I(K). A ligand-receptor binding assay indicated that CPH bound to the sigma-1 receptor. Similar effect of CPH were obtained from HEK-293 cells transfected with the α-subunit of Kv2.1. In overall, we reveal for the first time that CPH enhances the I(K) by modulating activity of PKA, and that the associated activation of the sigma-1 receptor/G(i)-protein pathway might be involved. Our findings illustrate an uncharacterized effect of CPH on neuron excitability through the I(K), which is independent of histamine H(1) and serotonin receptors.
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Affiliation(s)
- Yan-Lin He
- Institutes of Brain Science, School of Life Sciences and State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China
| | - Chun-Lei Zhang
- Institutes of Brain Science, School of Life Sciences and State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China
| | - Xiao-Fei Gao
- Institutes of Brain Science, School of Life Sciences and State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China
| | - Jin-Jing Yao
- Institutes of Brain Science, School of Life Sciences and State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China
| | - Chang-Long Hu
- Institutes of Brain Science, School of Life Sciences and State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China
| | - Yan-Ai Mei
- Institutes of Brain Science, School of Life Sciences and State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China
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Mavlyutov TA, Epstein ML, Liu P, Verbny YI, Ziskind-Conhaim L, Ruoho AE. Development of the sigma-1 receptor in C-terminals of motoneurons and colocalization with the N,N'-dimethyltryptamine forming enzyme, indole-N-methyl transferase. Neuroscience 2012; 206:60-8. [PMID: 22265729 PMCID: PMC3321351 DOI: 10.1016/j.neuroscience.2011.12.040] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2011] [Revised: 12/22/2011] [Accepted: 12/22/2011] [Indexed: 11/17/2022]
Abstract
The function of the sigma-1 receptor (S1R) has been linked to modulating the activities of ion channels and G-protein-coupled receptors (GPCR). In the CNS, the S1R is expressed ubiquitously but is enriched in mouse motoneurons (MN), where it is localized to subsurface cisternae of cholinergic postsynaptic densities, also known as C-terminals. We found that S1R is enriched in mouse spinal MN at late stages of embryonic development when it is first visualized in the endoplasmic reticulum. S1Rs appear to concentrate at C-terminals of mouse MN only on the second week of postnatal development. We found that indole-N-methyl transferase (INMT), an enzyme that converts tryptamine into the sigma-1 ligand dimethyltryptamine (DMT), is also localized to postsynaptic sites of C-terminals in close proximity to the S1R. This close association of INMT and S1Rs suggest that DMT is synthesized locally to effectively activate S1R in MN.
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Affiliation(s)
- T A Mavlyutov
- Department of Neuroscience, University of Wisconsin, School of Medicine and Public Health, 1300 University Ave, Madison, WI 53706, USA.
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Synthesis and binding assays of novel 3,3-dimethylpiperidine derivatives with various lipophilicities as σ1 receptor ligands. Bioorg Med Chem 2011; 19:7612-22. [DOI: 10.1016/j.bmc.2011.10.023] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2011] [Revised: 10/04/2011] [Accepted: 10/07/2011] [Indexed: 11/21/2022]
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