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Papadimitriou E, Koutsoudaki PN, Thanou I, Karagkouni D, Karamitros T, Chroni-Tzartou D, Gaitanou M, Gkemisis C, Margariti M, Xingi E, Tzartos SJ, Hatzigeorgiou AG, Thomaidou D. A miR-124-mediated post-transcriptional mechanism controlling the cell fate switch of astrocytes to induced neurons. Stem Cell Reports 2023; 18:915-935. [PMID: 36963393 PMCID: PMC10147664 DOI: 10.1016/j.stemcr.2023.02.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Revised: 02/21/2023] [Accepted: 02/23/2023] [Indexed: 03/26/2023] Open
Abstract
The microRNA (miRNA) miR-124 has been employed supplementary to neurogenic transcription factors (TFs) and other miRNAs to enhance direct neurogenic conversion. The aim of this study was to investigate whether miR-124 is sufficient to drive direct reprogramming of astrocytes to induced neurons (iNs) on its own and elucidate its independent mechanism of reprogramming action. Our data show that miR-124 is a potent driver of the reprogramming switch of astrocytes toward an immature neuronal fate by directly targeting the RNA-binding protein Zfp36L1 implicated in ARE-mediated mRNA decay and subsequently derepressing Zfp36L1 neurogenic interactome. To this end, miR-124 contribution in iNs' production largely recapitulates endogenous neurogenesis pathways, being further enhanced upon addition of the neurogenic compound ISX9, which greatly improves iNs' differentiation and functional maturation. Importantly, miR-124 is potent in guiding direct conversion of reactive astrocytes to immature iNs in vivo following cortical trauma, while ISX9 supplementation confers a survival advantage to newly produced iNs.
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Affiliation(s)
- Elsa Papadimitriou
- Neural Stem Cells and Neuroimaging Group, Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece
| | - Paraskevi N Koutsoudaki
- Neural Stem Cells and Neuroimaging Group, Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece
| | - Irini Thanou
- Neural Stem Cells and Neuroimaging Group, Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece
| | - Dimitra Karagkouni
- DIANA-Lab, Hellenic Pasteur Institute & Department of Computer Science and Biomedical Informatics, University of Thessaly, Larissa, Greece
| | - Timokratis Karamitros
- Bioinformatics and Applied Genomics Unit, Department of Microbiology, Hellenic Pasteur Institute, Athens, Greece
| | - Dafni Chroni-Tzartou
- Laboratory of Molecular Neurobiology and Immunology, Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece
| | - Maria Gaitanou
- Laboratory of Cellular and Molecular Neurobiology - Stem Cells, Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece
| | - Christos Gkemisis
- Neural Stem Cells and Neuroimaging Group, Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece
| | - Maria Margariti
- Neural Stem Cells and Neuroimaging Group, Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece
| | - Evangelia Xingi
- Light Microscopy Unit, Hellenic Pasteur Institute, Athens, Greece
| | - Socrates J Tzartos
- Laboratory of Molecular Neurobiology and Immunology, Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece
| | - Artemis G Hatzigeorgiou
- Bioinformatics and Applied Genomics Unit, Department of Microbiology, Hellenic Pasteur Institute, Athens, Greece
| | - Dimitra Thomaidou
- Neural Stem Cells and Neuroimaging Group, Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece; Light Microscopy Unit, Hellenic Pasteur Institute, Athens, Greece.
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Alexandris N, Lagoumintzis G, Chasapis CT, Leonidas DD, Papadopoulos GE, Tzartos SJ, Tsatsakis A, Eliopoulos E, Poulas K, Farsalinos K. Nicotinic cholinergic system and COVID-19: In silico evaluation of nicotinic acetylcholine receptor agonists as potential therapeutic interventions. Toxicol Rep 2020; 8:73-83. [PMID: 33425684 PMCID: PMC7776751 DOI: 10.1016/j.toxrep.2020.12.013] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 12/01/2020] [Accepted: 12/14/2020] [Indexed: 12/15/2022] Open
Abstract
SARS-CoV-2 infection was announced as a pandemic in March 2020. Since then, several scientists have focused on the low prevalence of smokers among hospitalized COVID-19 patients. These findings led to our hypothesis that the Nicotinic Cholinergic System (NCS) plays a crucial role in the manifestation of COVID-19 and its severe symptoms. Molecular modeling revealed that the SARS-CoV-2 Spike glycoprotein might bind to nicotinic acetylcholine receptors (nAChRs) through a cryptic epitope homologous to snake toxins, substrates well documented and known for their affinity to the nAChRs. This binding model could provide logical explanations for the acute inflammatory disorder in patients with COVID-19, which may be linked to severe dysregulation of NCS. In this study, we present a series of complexes with cholinergic agonists that can potentially prevent SARS-CoV-2 Spike glycoprotein from binding to nAChRs, avoiding dysregulation of the NCS and moderating the symptoms and clinical manifestations of COVID-19. If our hypothesis is verified by in vitro and in vivo studies, repurposing agents currently approved for smoking cessation and neurological conditions could provide the scientific community with a therapeutic option in severe COVID-19.
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Key Words
- ACh, Acetylcholine
- AChBP, Acetylcholine-binding protein
- ARDS, acute respiratory distress syndrome
- BLAST, Basic Local Alignment Search Tool
- CHARMM, Chemistry at Harvard Macromolecular Mechanics
- CNS, Central Nervous System
- COVID-19
- Cholinergic agonists
- CoV, coronavirus
- DCD, single precision binary FORTRAN
- ECD, extracellular domain
- HADDOCK, High Ambiguity Driven protein-protein DOCKing
- HMGB1, High-mobility group protein 1
- IL, Interleukin
- Jak2, Janus kinases 2
- LBD, Ligand Binding Domain
- MD, Molecular Dynamics
- MDS, Molecular Dynamics Simulations
- MERS, Middle East Respiratory Syndrome
- NAMD, Nanoscale Molecular Dynamics
- NCBI, National Center for Biotechnology Information
- NCS, Nicotinic Cholinergic System
- NF-kB, nuclear factor kappa-light-chain-enhancer of activated B cells
- NPT, constant number, pressure, energy
- NVT, constant number, volume, energy
- Nicotinic acetylcholine receptors
- PDB, Protein Data Bank
- PME, Particle Mesh Ewald
- PRODIGY, PROtein binDIng enerGY prediction
- PyMOL, Python Molecule
- RBD, Receptor Binding Domain
- RMSD, Root-mean-square deviation
- SARS, Severe Acute Respiratory Syndrome
- SARS-CoV-2
- SARS-CoV-2 S1, SARS - 2 Spike Subunit 1 protein
- STAT3, signal transducer and activator of transcription 3
- STD NMR, Saturation Transfer Difference Nuclear Magnetic Resonance
- Spike glycoprotein
- TNF, Tumor Necrosis Factor
- VMD, Visual Molecular Dynamics
- lig, ligand
- nAChRs, nicotinic acetylcholine receptors
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Affiliation(s)
- Nikolaos Alexandris
- Laboratory of Molecular Biology and Immunology, Department of Pharmacy, University of Patras, 26500, Rio-Patras, Greece
| | - George Lagoumintzis
- Laboratory of Molecular Biology and Immunology, Department of Pharmacy, University of Patras, 26500, Rio-Patras, Greece
- Institute of Research and Innovation - IRIS, Patras Science Park SA, 26500 Patras, Greece
| | - Christos T. Chasapis
- Laboratory of Molecular Biology and Immunology, Department of Pharmacy, University of Patras, 26500, Rio-Patras, Greece
| | - Demetres D. Leonidas
- Department of Biochemistry and Biotechnology, University of Thessaly, Biopolis, 41500 Larissa, Greece
| | - Georgios E. Papadopoulos
- Department of Biochemistry and Biotechnology, University of Thessaly, Biopolis, 41500 Larissa, Greece
| | | | | | - Elias Eliopoulos
- Department of Biotechnology, Laboratory of Genetics, Agricultural University of Athens, Iera Odos 75, 11855 Athens, Greece
| | - Konstantinos Poulas
- Laboratory of Molecular Biology and Immunology, Department of Pharmacy, University of Patras, 26500, Rio-Patras, Greece
- Institute of Research and Innovation - IRIS, Patras Science Park SA, 26500 Patras, Greece
| | - Konstantinos Farsalinos
- Laboratory of Molecular Biology and Immunology, Department of Pharmacy, University of Patras, 26500, Rio-Patras, Greece
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Abstract
Myasthenia gravis (MG) is the most common autoimmune disorder affecting the neuromuscular junction, characterized by skeletal muscle weakness and fatigability. It is caused by autoantibodies targeting proteins of the neuromuscular junction; ~85% of MG patients have autoantibodies against the muscle acetylcholine receptor (AChR-MG), whereas about 5% of MG patients have autoantibodies against the muscle specific kinase (MuSK-MG). In the remaining about 10% of patients no autoantibodies can be found with the classical diagnostics for AChR and MuSK antibodies (seronegative MG, SN-MG). Since serological tests are relatively easy and non-invasive for disease diagnosis, the improvement of methods for the detection of known autoantibodies or the discovery of novel autoantibody specificities to diminish SN-MG and to facilitate differential diagnosis of similar diseases, is crucial. Radioimmunoprecipitation assays (RIPA) are the staple for MG antibody detection, but over the past years, using cell-based assays (CBAs) or improved highly sensitive RIPAs, it has been possible to detect autoantibodies in previously SN-MG patients. This led to the identification of more patients with antibodies to the classical antigens AChR and MuSK and to the third MG autoantigen, the low-density lipoprotein receptor-related protein 4 (LRP4), while antibodies against other extracellular or intracellular targets, such as agrin, Kv1.4 potassium channels, collagen Q, titin, the ryanodine receptor and cortactin have been found in some MG patients. Since the autoantigen targeted determines in part the clinical manifestations, prognosis and response to treatment, serological tests are not only indispensable for initial diagnosis, but also for monitoring treatment efficacy. Importantly, knowing the autoantibody profile of MG patients could allow for more efficient personalized therapeutic approaches. Significant progress has been made over the past years toward the development of antigen-specific therapies, targeting only the specific immune cells or autoantibodies involved in the autoimmune response. In this review, we will present the progress made toward the development of novel sensitive autoantibody detection assays, the identification of new MG autoantigens, and the implications for improved antigen-specific therapeutics. These advancements increase our understanding of MG pathology and improve patient quality of life by providing faster, more accurate diagnosis and better disease management.
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Affiliation(s)
| | - Socrates J Tzartos
- Tzartos NeuroDiagnostics, Athens, Greece.,Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece
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Lazaridis K, Tzartos SJ. Autoantibody Specificities in Myasthenia Gravis; Implications for Improved Diagnostics and Therapeutics. Front Immunol 2020; 11:212. [PMID: 32117321 PMCID: PMC7033452 DOI: 10.3389/fimmu.2020.00212] [Citation(s) in RCA: 106] [Impact Index Per Article: 26.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2019] [Accepted: 01/27/2020] [Indexed: 12/13/2022] Open
Abstract
Myasthenia gravis (MG) is an autoimmune disease characterized by muscle weakness and fatiguability of skeletal muscles. It is an antibody-mediated disease, caused by autoantibodies targeting neuromuscular junction proteins. In the majority of patients (~85%) antibodies against the muscle acetylcholine receptor (AChR) are detected, while in 6% antibodies against the muscle-specific kinase (MuSK) are detected. In ~10% of MG patients no autoantibodies can be found with the classical diagnostics for AChR and MuSK antibodies (seronegative MG, SN-MG), making the improvement of methods for the detection of known autoantibodies or the discovery of novel antigenic targets imperative. Over the past years, using cell-based assays or improved highly sensitive immunoprecipitation assays, it has been possible to detect autoantibodies in previously SN-MG patients, including the identification of the low-density lipoprotein receptor-related protein 4 (LRP4) as a third MG autoantigen, as well as AChR and MuSK antibodies undetectable by conventional methods. Furthermore, antibodies against other extracellular or intracellular targets, such as titin, the ryanodine receptor, agrin, collagen Q, Kv1.4 potassium channels and cortactin have been found in some MG patients, which can be useful biomarkers. In addition to the improvement of diagnosis, the identification of the patients' autoantibody specificity is important for their stratification into respective subgroups, which can differ in terms of clinical manifestations, prognosis and most importantly their response to therapies. The knowledge of the autoantibody profile of MG patients would allow for a therapeutic strategy tailored to their MG subgroup. This is becoming especially relevant as there is increasing progress toward the development of antigen-specific therapies, targeting only the specific autoantibodies or immune cells involved in the autoimmune response, such as antigen-specific immunoadsorption, which have shown promising results. We will herein review the advances made by us and others toward development of more sensitive detection methods and the identification of new antibody targets in MG, and discuss their significance in MG diagnosis and therapy. Overall, the development of novel autoantibody assays is aiding in the more accurate diagnosis and classification of MG patients, supporting the development of advanced therapeutics and ultimately the improvement of disease management and patient quality of life.
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Affiliation(s)
| | - Socrates J Tzartos
- Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece.,Tzartos NeuroDiagnostics, Athens, Greece
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Lazaridis K, Baltatzidou V, Tektonidis N, Tzartos SJ. Antigen-specific immunoadsorption of MuSK autoantibodies as a treatment of MuSK-induced experimental autoimmune myasthenia gravis. J Neuroimmunol 2019; 339:577136. [PMID: 31855721 DOI: 10.1016/j.jneuroim.2019.577136] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Revised: 12/10/2019] [Accepted: 12/11/2019] [Indexed: 11/16/2022]
Abstract
Myasthenia gravis (MG) is an autoimmune disease affecting the neuromuscular junction. Approximately 9% of MG patients have autoantibodies targeting the muscle specific kinase (MuSK), and are challenging therapeutically, since they often present with more severe symptoms. A useful therapy is plasmapheresis, but it is highly non-specific. Antigen-specific immunoadsorption would only remove the pathogenic autoantibodies, minimizing the possible side effects and maximizing the benefit. We used rats with human MuSK-induced experimental autoimmune MG to perform antigen-specific immunoadsorptions, and found it very effective, resulting in a dramatic autoantibody titer decrease, while immunoadsorbed, but not mock-treated, animals showed an significant improvement of their clinical symptoms. Overall, the procedure was efficient, supporting its application for MG treatment.
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Affiliation(s)
| | | | | | - Socrates J Tzartos
- Hellenic Pasteur Institute, Athens, Greece; Tzartos NeuroDiagnostics, Athens, Greece.
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6
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Lebedev DS, Kryukova EV, Ivanov IA, Egorova NS, Timofeev ND, Spirova EN, Tufanova EY, Siniavin AE, Kudryavtsev DS, Kasheverov IE, Zouridakis M, Katsarava R, Zavradashvili N, Iagorshvili I, Tzartos SJ, Tsetlin VI. Oligoarginine Peptides, a New Family of Nicotinic Acetylcholine Receptor Inhibitors. Mol Pharmacol 2019; 96:664-673. [PMID: 31492697 DOI: 10.1124/mol.119.117713] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Accepted: 08/26/2019] [Indexed: 12/28/2022] Open
Abstract
Many peptide ligands of nicotinic acetylcholine receptors (nAChRs) contain a large number of positively charged amino acid residues, a striking example being conotoxins RgIA and GeXIVA from marine mollusk venom, with an arginine content of >30%. To determine whether peptides built exclusively from arginine residues will interact with different nAChR subtypes or with their structural homologs such as the acetylcholine-binding protein and ligand-binding domain of the nAChR α9 subunit, we synthesized a series of R3, R6, R8, and R16 oligoarginines and investigated their activity by competition with radioiodinated α-bungarotoxin, two-electrode voltage-clamp electrophysiology, and calcium imaging. R6 and longer peptides inhibited muscle-type nAChRs, α7 nAChRs, and α3β2 nAChRs in the micromolar range. The most efficient inhibition of ion currents was detected for muscle nAChR by R16 (IC50 = 157 nM) and for the α9α10 subtype by R8 and R16 (IC50 = 44 and 120 nM, respectively). Since the R8 affinity for other tested nAChRs was 100-fold lower, R8 appears to be a selective antagonist of α9α10 nAChR. For R8, the electrophysiological and competition experiments indicated the existence of two distinct binding sites on α9α10 nAChR. Since modified oligoarginines and other cationic molecules are widely used as cell-penetrating peptides, we studied several cationic polymers and demonstrated their nAChR inhibitory activity. SIGNIFICANT STATEMENT: By using radioligand analysis, electrophysiology, and calcium imaging, we found that oligoarginine peptides are a new group of inhibitors for muscle nicotinic acetylcholine receptors (nAChRs) and some neuronal nAChRs, the most active being those with 16 and 8 Arg residues. Such compounds and other cationic polymers are cell-penetrating tools for drug delivery, and we also demonstrated the inhibition of nAChRs for several of the latter. Possible positive and negative consequences of such an action should be taken into account.
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Affiliation(s)
- Dmitry S Lebedev
- Department of Molecular Neuroimmune Signaling, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia (D.S.L., E.V.K., I.A.I., N.S.E., N.D.T., E.N.S., E.Y.T., A.E.S., D.S.K., I.E.K., V.I.T.); Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece (M.Z., S.J.T.); Institute of Molecular Medicine, Sechenov First Moscow State Medical University, Moscow, Russia (I.E.K.); Institute of Chemistry and Molecular Engineering, Agricultural University of Georgia, Kakha Bendukidze University Campus, Tbilisi, Georgia (R.K., N.Z., I.I.); and PhysBio of MePhI, Moscow, Russia (V.I.T.)
| | - Elena V Kryukova
- Department of Molecular Neuroimmune Signaling, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia (D.S.L., E.V.K., I.A.I., N.S.E., N.D.T., E.N.S., E.Y.T., A.E.S., D.S.K., I.E.K., V.I.T.); Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece (M.Z., S.J.T.); Institute of Molecular Medicine, Sechenov First Moscow State Medical University, Moscow, Russia (I.E.K.); Institute of Chemistry and Molecular Engineering, Agricultural University of Georgia, Kakha Bendukidze University Campus, Tbilisi, Georgia (R.K., N.Z., I.I.); and PhysBio of MePhI, Moscow, Russia (V.I.T.)
| | - Igor A Ivanov
- Department of Molecular Neuroimmune Signaling, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia (D.S.L., E.V.K., I.A.I., N.S.E., N.D.T., E.N.S., E.Y.T., A.E.S., D.S.K., I.E.K., V.I.T.); Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece (M.Z., S.J.T.); Institute of Molecular Medicine, Sechenov First Moscow State Medical University, Moscow, Russia (I.E.K.); Institute of Chemistry and Molecular Engineering, Agricultural University of Georgia, Kakha Bendukidze University Campus, Tbilisi, Georgia (R.K., N.Z., I.I.); and PhysBio of MePhI, Moscow, Russia (V.I.T.)
| | - Natalia S Egorova
- Department of Molecular Neuroimmune Signaling, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia (D.S.L., E.V.K., I.A.I., N.S.E., N.D.T., E.N.S., E.Y.T., A.E.S., D.S.K., I.E.K., V.I.T.); Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece (M.Z., S.J.T.); Institute of Molecular Medicine, Sechenov First Moscow State Medical University, Moscow, Russia (I.E.K.); Institute of Chemistry and Molecular Engineering, Agricultural University of Georgia, Kakha Bendukidze University Campus, Tbilisi, Georgia (R.K., N.Z., I.I.); and PhysBio of MePhI, Moscow, Russia (V.I.T.)
| | - Nikita D Timofeev
- Department of Molecular Neuroimmune Signaling, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia (D.S.L., E.V.K., I.A.I., N.S.E., N.D.T., E.N.S., E.Y.T., A.E.S., D.S.K., I.E.K., V.I.T.); Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece (M.Z., S.J.T.); Institute of Molecular Medicine, Sechenov First Moscow State Medical University, Moscow, Russia (I.E.K.); Institute of Chemistry and Molecular Engineering, Agricultural University of Georgia, Kakha Bendukidze University Campus, Tbilisi, Georgia (R.K., N.Z., I.I.); and PhysBio of MePhI, Moscow, Russia (V.I.T.)
| | - Ekaterina N Spirova
- Department of Molecular Neuroimmune Signaling, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia (D.S.L., E.V.K., I.A.I., N.S.E., N.D.T., E.N.S., E.Y.T., A.E.S., D.S.K., I.E.K., V.I.T.); Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece (M.Z., S.J.T.); Institute of Molecular Medicine, Sechenov First Moscow State Medical University, Moscow, Russia (I.E.K.); Institute of Chemistry and Molecular Engineering, Agricultural University of Georgia, Kakha Bendukidze University Campus, Tbilisi, Georgia (R.K., N.Z., I.I.); and PhysBio of MePhI, Moscow, Russia (V.I.T.)
| | - Elizaveta Yu Tufanova
- Department of Molecular Neuroimmune Signaling, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia (D.S.L., E.V.K., I.A.I., N.S.E., N.D.T., E.N.S., E.Y.T., A.E.S., D.S.K., I.E.K., V.I.T.); Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece (M.Z., S.J.T.); Institute of Molecular Medicine, Sechenov First Moscow State Medical University, Moscow, Russia (I.E.K.); Institute of Chemistry and Molecular Engineering, Agricultural University of Georgia, Kakha Bendukidze University Campus, Tbilisi, Georgia (R.K., N.Z., I.I.); and PhysBio of MePhI, Moscow, Russia (V.I.T.)
| | - Andrei E Siniavin
- Department of Molecular Neuroimmune Signaling, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia (D.S.L., E.V.K., I.A.I., N.S.E., N.D.T., E.N.S., E.Y.T., A.E.S., D.S.K., I.E.K., V.I.T.); Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece (M.Z., S.J.T.); Institute of Molecular Medicine, Sechenov First Moscow State Medical University, Moscow, Russia (I.E.K.); Institute of Chemistry and Molecular Engineering, Agricultural University of Georgia, Kakha Bendukidze University Campus, Tbilisi, Georgia (R.K., N.Z., I.I.); and PhysBio of MePhI, Moscow, Russia (V.I.T.)
| | - Denis S Kudryavtsev
- Department of Molecular Neuroimmune Signaling, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia (D.S.L., E.V.K., I.A.I., N.S.E., N.D.T., E.N.S., E.Y.T., A.E.S., D.S.K., I.E.K., V.I.T.); Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece (M.Z., S.J.T.); Institute of Molecular Medicine, Sechenov First Moscow State Medical University, Moscow, Russia (I.E.K.); Institute of Chemistry and Molecular Engineering, Agricultural University of Georgia, Kakha Bendukidze University Campus, Tbilisi, Georgia (R.K., N.Z., I.I.); and PhysBio of MePhI, Moscow, Russia (V.I.T.)
| | - Igor E Kasheverov
- Department of Molecular Neuroimmune Signaling, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia (D.S.L., E.V.K., I.A.I., N.S.E., N.D.T., E.N.S., E.Y.T., A.E.S., D.S.K., I.E.K., V.I.T.); Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece (M.Z., S.J.T.); Institute of Molecular Medicine, Sechenov First Moscow State Medical University, Moscow, Russia (I.E.K.); Institute of Chemistry and Molecular Engineering, Agricultural University of Georgia, Kakha Bendukidze University Campus, Tbilisi, Georgia (R.K., N.Z., I.I.); and PhysBio of MePhI, Moscow, Russia (V.I.T.)
| | - Marios Zouridakis
- Department of Molecular Neuroimmune Signaling, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia (D.S.L., E.V.K., I.A.I., N.S.E., N.D.T., E.N.S., E.Y.T., A.E.S., D.S.K., I.E.K., V.I.T.); Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece (M.Z., S.J.T.); Institute of Molecular Medicine, Sechenov First Moscow State Medical University, Moscow, Russia (I.E.K.); Institute of Chemistry and Molecular Engineering, Agricultural University of Georgia, Kakha Bendukidze University Campus, Tbilisi, Georgia (R.K., N.Z., I.I.); and PhysBio of MePhI, Moscow, Russia (V.I.T.)
| | - Ramaz Katsarava
- Department of Molecular Neuroimmune Signaling, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia (D.S.L., E.V.K., I.A.I., N.S.E., N.D.T., E.N.S., E.Y.T., A.E.S., D.S.K., I.E.K., V.I.T.); Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece (M.Z., S.J.T.); Institute of Molecular Medicine, Sechenov First Moscow State Medical University, Moscow, Russia (I.E.K.); Institute of Chemistry and Molecular Engineering, Agricultural University of Georgia, Kakha Bendukidze University Campus, Tbilisi, Georgia (R.K., N.Z., I.I.); and PhysBio of MePhI, Moscow, Russia (V.I.T.)
| | - Nino Zavradashvili
- Department of Molecular Neuroimmune Signaling, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia (D.S.L., E.V.K., I.A.I., N.S.E., N.D.T., E.N.S., E.Y.T., A.E.S., D.S.K., I.E.K., V.I.T.); Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece (M.Z., S.J.T.); Institute of Molecular Medicine, Sechenov First Moscow State Medical University, Moscow, Russia (I.E.K.); Institute of Chemistry and Molecular Engineering, Agricultural University of Georgia, Kakha Bendukidze University Campus, Tbilisi, Georgia (R.K., N.Z., I.I.); and PhysBio of MePhI, Moscow, Russia (V.I.T.)
| | - Ia Iagorshvili
- Department of Molecular Neuroimmune Signaling, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia (D.S.L., E.V.K., I.A.I., N.S.E., N.D.T., E.N.S., E.Y.T., A.E.S., D.S.K., I.E.K., V.I.T.); Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece (M.Z., S.J.T.); Institute of Molecular Medicine, Sechenov First Moscow State Medical University, Moscow, Russia (I.E.K.); Institute of Chemistry and Molecular Engineering, Agricultural University of Georgia, Kakha Bendukidze University Campus, Tbilisi, Georgia (R.K., N.Z., I.I.); and PhysBio of MePhI, Moscow, Russia (V.I.T.)
| | - Socrates J Tzartos
- Department of Molecular Neuroimmune Signaling, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia (D.S.L., E.V.K., I.A.I., N.S.E., N.D.T., E.N.S., E.Y.T., A.E.S., D.S.K., I.E.K., V.I.T.); Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece (M.Z., S.J.T.); Institute of Molecular Medicine, Sechenov First Moscow State Medical University, Moscow, Russia (I.E.K.); Institute of Chemistry and Molecular Engineering, Agricultural University of Georgia, Kakha Bendukidze University Campus, Tbilisi, Georgia (R.K., N.Z., I.I.); and PhysBio of MePhI, Moscow, Russia (V.I.T.)
| | - Victor I Tsetlin
- Department of Molecular Neuroimmune Signaling, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia (D.S.L., E.V.K., I.A.I., N.S.E., N.D.T., E.N.S., E.Y.T., A.E.S., D.S.K., I.E.K., V.I.T.); Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece (M.Z., S.J.T.); Institute of Molecular Medicine, Sechenov First Moscow State Medical University, Moscow, Russia (I.E.K.); Institute of Chemistry and Molecular Engineering, Agricultural University of Georgia, Kakha Bendukidze University Campus, Tbilisi, Georgia (R.K., N.Z., I.I.); and PhysBio of MePhI, Moscow, Russia (V.I.T.)
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Andreou A, Giastas P, Arnaouteli S, Tzanodaskalaki M, Tzartos SJ, Bethanis K, Bouriotis V, Eliopoulos EE. The putative polysaccharide deacetylase Ba0331: cloning, expression, crystallization and structure determination. Acta Crystallogr F Struct Biol Commun 2019; 75:312-320. [PMID: 30950833 DOI: 10.1107/s2053230x19001766] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Accepted: 01/30/2019] [Indexed: 11/10/2022]
Abstract
Ba0331 is a putative polysaccharide deacetylase from Bacillus anthracis, the etiological agent of the disease anthrax, that contributes to adaptation of the bacterium under extreme conditions and to maintenance of the cell shape. In the present study, the crystal structure of Ba0331 was determined at 2.6 Å resolution. The structure consists of two domains: a fibronectin type 3-like (Fn3-like) domain and a NodB catalytic domain. The latter is present in all carbohydrate esterase family 4 enzymes, while a comparative analysis of the Fn3-like domain revealed structural plasticity despite the retention of the conserved Fn3-like domain characteristics.
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Affiliation(s)
- Athena Andreou
- Department of Biotechnology, Agricultural University of Athens, Iera Odos 75, 11855 Athens, Greece
| | - Petros Giastas
- Department of Biotechnology, Agricultural University of Athens, Iera Odos 75, 11855 Athens, Greece
| | - Sofia Arnaouteli
- Department of Biology, Enzyme Biotechnology Group, University of Crete, Vasilika Vouton, 70013 Heraklion, Crete, Greece
| | - Mary Tzanodaskalaki
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology, Hellas N. Plastira 100, 70013 Heraklion, Crete, Greece
| | - Socrates J Tzartos
- Department of Neurobiology, Hellenic Pasteur Institute, Vasilissis Sofias 127, 11521 Athens, Greece
| | - Kostas Bethanis
- Department of Biotechnology, Agricultural University of Athens, Iera Odos 75, 11855 Athens, Greece
| | - Vassilis Bouriotis
- Department of Biology, Enzyme Biotechnology Group, University of Crete, Vasilika Vouton, 70013 Heraklion, Crete, Greece
| | - Elias E Eliopoulos
- Department of Biotechnology, Agricultural University of Athens, Iera Odos 75, 11855 Athens, Greece
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8
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Kryukova EV, Ivanov IA, Lebedev DS, Spirova EN, Egorova NS, Zouridakis M, Kasheverov IE, Tzartos SJ, Tsetlin VI. Orthosteric and/or Allosteric Binding of α-Conotoxins to Nicotinic Acetylcholine Receptors and Their Models. Mar Drugs 2018; 16:md16120460. [PMID: 30469507 PMCID: PMC6315749 DOI: 10.3390/md16120460] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 11/09/2018] [Accepted: 11/20/2018] [Indexed: 12/19/2022] Open
Abstract
α-Conotoxins from Conus snails are capable of distinguishing muscle and neuronal nicotinic acetylcholine receptors (nAChRs). α-Conotoxin RgIA and αO-conotoxin GeXIVA, blocking neuronal α9α10 nAChR, are potential analgesics. Typically, α-conotoxins bind to the orthosteric sites for agonists/competitive antagonists, but αO-conotoxin GeXIVA was proposed to attach allosterically, judging by electrophysiological experiments on α9α10 nAChR. We decided to verify this conclusion by radioligand analysis in competition with α-bungarotoxin (αBgt) on the ligand-binding domain of the nAChR α9 subunit (α9 LBD), where, from the X-ray analysis, αBgt binds at the orthosteric site. A competition with αBgt was registered for GeXIVA and RgIA, IC50 values being in the micromolar range. However, high nonspecific binding of conotoxins (detected with their radioiodinated derivatives) to His6-resin attaching α9 LBD did not allow us to accurately measure IC50s. However, IC50s were measured for binding to Aplysia californica AChBP: the RgIA globular isomer, known to be active against α9α10 nAChR, was more efficient than the ribbon one, whereas all three GeXIVA isomers had similar potencies at low µM. Thus, radioligand analysis indicated that both conotoxins can attach to the orthosteric sites in these nAChR models, which should be taken into account in the design of analgesics on the basis of these conotoxins.
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Affiliation(s)
- Elena V Kryukova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya Street, 16/10, 117997 Moscow, Russia.
| | - Igor A Ivanov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya Street, 16/10, 117997 Moscow, Russia.
| | - Dmitry S Lebedev
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya Street, 16/10, 117997 Moscow, Russia.
| | - Ekaterina N Spirova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya Street, 16/10, 117997 Moscow, Russia.
| | - Natalia S Egorova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya Street, 16/10, 117997 Moscow, Russia.
| | - Marios Zouridakis
- Department of Neurobiology, Hellenic Pasteur Institute, 127, Vas. Sofias ave., Athens 115 21, Greece.
| | - Igor E Kasheverov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya Street, 16/10, 117997 Moscow, Russia.
- Institute of Molecular Medicine, Sechenov First Moscow State Medical University, Trubetskaya Street 8, bld. 2, 119991 Moscow, Russia.
| | - Socrates J Tzartos
- Department of Neurobiology, Hellenic Pasteur Institute, 127, Vas. Sofias ave., Athens 115 21, Greece.
| | - Victor I Tsetlin
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya Street, 16/10, 117997 Moscow, Russia.
- PhysBio of MEPhI, Kashirskoye Ave., 31, 115409 Moscow, Russia.
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9
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Trakas N, Tzartos SJ. Immunostick ELISA for rapid and easy diagnosis of myasthenia gravis. J Immunol Methods 2018; 460:107-112. [DOI: 10.1016/j.jim.2018.06.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Revised: 06/14/2018] [Accepted: 06/28/2018] [Indexed: 01/20/2023]
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Abstract
This themed section of the British Journal of Pharmacology is the product of a conference that focussed on nicotinic ACh receptors (nAChRs) that was held on the Greek island of Crete from 7 to 11 May 2017. 'Nicotinic acetylcholine receptors 2017' was the fourth in a series of triennial international meetings that have provided a regular forum for scientists working on all aspects of nAChRs to meet and to discuss new developments. In addition to many of the regular participants, each meeting has also attracted a new group of scientists working in a fast-moving area of research. This themed section comprises both review articles and original research papers on nAChRs. LINKED ARTICLES This article is part of a themed section on Nicotinic Acetylcholine Receptors. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v175.11/issuetoc/.
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Affiliation(s)
- Sue Wonnacott
- Department of Biology & BiochemistryUniversity of BathBathUK
| | - Isabel Bermudez
- Department of Biological and Medical SciencesOxford Brookes UniversityOxfordUK
| | - Neil S Millar
- Department of Neuroscience, Physiology & PharmacologyUniversity College LondonLondonUK
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11
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Giastas P, Andreou A, Papakyriakou A, Koutsioulis D, Balomenou S, Tzartos SJ, Bouriotis V, Eliopoulos EE. Structures of the Peptidoglycan N-Acetylglucosamine Deacetylase Bc1974 and Its Complexes with Zinc Metalloenzyme Inhibitors. Biochemistry 2018; 57:753-763. [PMID: 29257674 DOI: 10.1021/acs.biochem.7b00919] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The cell wall peptidoglycan is recognized as a primary target of the innate immune system, and usually its disintegration results in bacterial lysis. Bacillus cereus, a close relative of the highly virulent Bacillus anthracis, contains 10 polysaccharide deacetylases. Among these, the peptidoglycan N-acetylglucosamine deacetylase Bc1974 is the highest homologue to the Bacillus anthracis Ba1977 that is required for full virulence and is involved in resistance to the host's lysozyme. These metalloenzymes belong to the carbohydrate esterase family 4 (CE4) and are attractive targets for the development of new anti-infective agents. Herein we report the first X-ray crystal structures of the NodB domain of Bc1974, the conserved catalytic core of CE4s, in the unliganded form and in complex with four known metalloenzyme inhibitors and two amino acid hydroxamates that target the active site metal. These structures revealed the presence of two conformational states of a catalytic loop known as motif-4 (MT4), which were not observed previously for peptidoglycan deacetylases, but were recently shown in the structure of a Vibrio clolerae chitin deacetylase. By employing molecular docking of a substrate model, we describe a catalytic mechanism that probably involves initial binding of the substrate in a receptive, more open state of MT4 and optimal catalytic activity in the closed state of MT4, consistent with the previous observations. The ligand-bound structures presented here, in addition to the five Bc1974 inhibitors identified, provide a valuable basis for the design of antibacterial agents that target the peptidoglycan deacetylase Ba1977.
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Affiliation(s)
- Petros Giastas
- Department of Biotechnology, Laboratory of Genetics, Agricultural University of Athens , Iera Odos 75, 11855 Athens, Greece.,Department of Neurobiology, Hellenic Pasteur Institute , Vasilissis Sofias 127, 11521 Athens, Greece
| | - Athena Andreou
- Department of Biotechnology, Laboratory of Genetics, Agricultural University of Athens , Iera Odos 75, 11855 Athens, Greece
| | - Athanasios Papakyriakou
- Department of Biotechnology, Laboratory of Genetics, Agricultural University of Athens , Iera Odos 75, 11855 Athens, Greece.,Institute of Biosciences and Applications, NCSR "Demokritos" , 15310 Aghia Paraskevi, Athens, Greece
| | - Dimitris Koutsioulis
- Institute of Molecular Biology and Biotechnology, FORTH , 70013 Heraklion, Crete, Greece
| | - Stavroula Balomenou
- Institute of Molecular Biology and Biotechnology, FORTH , 70013 Heraklion, Crete, Greece.,Department of Biology, Enzyme Biotechnology Group, University of Crete , Vasilika Vouton, 70013 Heraklion, Crete, Greece
| | - Socrates J Tzartos
- Department of Neurobiology, Hellenic Pasteur Institute , Vasilissis Sofias 127, 11521 Athens, Greece
| | - Vassilis Bouriotis
- Institute of Molecular Biology and Biotechnology, FORTH , 70013 Heraklion, Crete, Greece.,Department of Biology, Enzyme Biotechnology Group, University of Crete , Vasilika Vouton, 70013 Heraklion, Crete, Greece
| | - Elias E Eliopoulos
- Department of Biotechnology, Laboratory of Genetics, Agricultural University of Athens , Iera Odos 75, 11855 Athens, Greece
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12
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Lazaridis K, Dalianoudis I, Baltatzidi V, Tzartos SJ. Specific removal of autoantibodies by extracorporeal immunoadsorption ameliorates experimental autoimmune myasthenia gravis. J Neuroimmunol 2017; 312:24-30. [DOI: 10.1016/j.jneuroim.2017.09.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 09/03/2017] [Accepted: 09/05/2017] [Indexed: 11/29/2022]
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13
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Tzartos JS, Stergiou C, Daoussis D, Zisimopoulou P, Andonopoulos AP, Zolota V, Tzartos SJ. Antibodies to aquaporins are frequent in patients with primary Sjögren’s syndrome. Rheumatology (Oxford) 2017; 56:2114-2122. [DOI: 10.1093/rheumatology/kex328] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Indexed: 11/14/2022] Open
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14
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Giastas P, Zouridakis M, Tzartos SJ. Understanding structure-function relationships of the human neuronal acetylcholine receptor: insights from the first crystal structures of neuronal subunits. Br J Pharmacol 2017; 175:1880-1891. [PMID: 28452148 DOI: 10.1111/bph.13838] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Revised: 04/13/2017] [Accepted: 04/20/2017] [Indexed: 01/27/2023] Open
Abstract
Nicotinic ACh receptors (nAChRs) are the best studied members of the superfamily of pentameric ligand-gated ion channels (pLGICs). Neuronal nAChRs regulate neuronal excitability and neurotransmitter release in the nervous system and form either homo- or hetero-pentameric complexes with various combinations of the 11 neuronal nAChR subunits (α2-7, α9, α10 and β2-4) known to exist in humans. In addition to their wide distribution in the nervous system, neuronal nAChRs have been also found in immune cells and many peripheral tissues. These nAChRs are important drug targets for neurological and neuropsychiatric diseases (e.g. Alzheimer's, schizophrenia) and substance addiction (e.g. nicotine), as well as in a variety of diseases such as chronic pain, auditory disorders and some cancers. To decipher the functional mechanisms of human nAChRs and develop efficient and specific therapeutic drugs, elucidation of their high-resolution structures is needed. Recent studies, including the X-ray crystal structures of the near-intact α4β2 nAChR and of the ligand-binding domains of the α9 and α2 subunits, have advanced our knowledge on the detailed structure of the ligand-binding sites formed between the same and different subunits and revealed many other functionally important interactions. The aim of this review is to highlight some of the structural and functional findings of these studies and to compare them with recent breakthrough findings on other pLGIC members and earlier data from their homologous ACh-binding proteins. LINKED ARTICLES This article is part of a themed section on Nicotinic Acetylcholine Receptors. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v175.11/issuetoc.
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Affiliation(s)
- Petros Giastas
- Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece
| | - Marios Zouridakis
- Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece
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15
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Cung MT, Marraud M, Tsikaris V, Sakarellos C, Papadouli I, Tzartos SJ. Étude par RMN-2D des interactions antigène-anticorps : reconnaissance des analogues décapeptidiques du fragment α67-76 du récepteur RACh par les anticorps anti-RACh. ACTA ACUST UNITED AC 2017. [DOI: 10.1051/jcp/1992890167] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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16
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Cordts I, Bodart N, Hartmann K, Karagiorgou K, Tzartos JS, Mei L, Reimann J, Van Damme P, Rivner MH, Vigneron A, Weis J, Schulz JB, Tzartos SJ, Claeys KG. Screening for lipoprotein receptor-related protein 4-, agrin-, and titin-antibodies and exploring the autoimmune spectrum in myasthenia gravis. J Neurol 2017; 264:1193-1203. [DOI: 10.1007/s00415-017-8514-z] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Revised: 04/24/2017] [Accepted: 05/08/2017] [Indexed: 01/09/2023]
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17
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Hong Y, Skeie GO, Zisimopoulou P, Karagiorgou K, Tzartos SJ, Gao X, Yue YX, Romi F, Zhang X, Li HF, Gilhus NE. Juvenile-onset myasthenia gravis: autoantibody status, clinical characteristics and genetic polymorphisms. J Neurol 2017; 264:955-962. [PMID: 28364296 DOI: 10.1007/s00415-017-8478-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Revised: 03/27/2017] [Accepted: 03/28/2017] [Indexed: 01/10/2023]
Abstract
Myasthenia gravis (MG) is an autoimmune disorder mediated by antibodies against proteins at the neuromuscular junction. Juvenile-onset MG (JMG) has been reported to have special characteristics. It is still unclear whether there are any pathogenic and genetic differences between juvenile and adult MG. In this study, we evaluated the clinical characteristics, autoantibody status (antibodies against AChR, MuSK, LRP4, titin and RyR) and genetic susceptibility (CHRNA1, CTLA4 and AIRE) in 114 Chinese JMG patients, and compared with 207 young adult MG patients (onset age 18-40 years). JMG patients were classified into two subgroups: the very early onset group (<8 years) and puberty onset group (8-18 years). The very early onset MG patients had a higher proportion of ocular MG and thymus hyperplasia, compared with puberty onset MG and young adult MG (P < 0.05). AChR antibodies were found in majority of JMG patients and were associated with more severe disease (P < 0.05), while other antibodies were rare in JMG. Moreover, the very early onset MG had a more prominent genetic predisposition than puberty and adult MG, affecting the susceptible genes CHRNA1 and CTLA4. JMG has the same pathogenic background as adult MG, but has typical clinical features and a prominent genetic predisposition in very early onset patients (<8 years). Specific therapeutic considerations are needed.
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Affiliation(s)
- Yu Hong
- Department of Clinical Medicine, University of Bergen, Bergen, Norway
| | - Geir Olve Skeie
- Department of Clinical Medicine, University of Bergen, Bergen, Norway
- Department of Neurology, Haukeland University Hospital, 5021, Bergen, Norway
| | | | - Katerina Karagiorgou
- Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece
- Tzartos NeuroDiagnostics, Athens, Greece
| | - Socrates J Tzartos
- Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece
- Tzartos NeuroDiagnostics, Athens, Greece
| | - Xiang Gao
- Department of Neurology, Affiliated Hospital of Qingdao University, Qingdao, China
| | - Yao-Xian Yue
- Department of Neurology, Qilu Hospital of Shandong University, Jinan, 250012, China
| | - Fredrik Romi
- Department of Clinical Medicine, University of Bergen, Bergen, Norway
- Department of Neurology, Haukeland University Hospital, 5021, Bergen, Norway
| | - Xu Zhang
- Department of Neurology, Affiliated Hospital of Qingdao University, Qingdao, China
| | - Hai-Feng Li
- Department of Neurology, Qilu Hospital of Shandong University, Jinan, 250012, China.
| | - Nils Erik Gilhus
- Department of Clinical Medicine, University of Bergen, Bergen, Norway.
- Department of Neurology, Haukeland University Hospital, 5021, Bergen, Norway.
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18
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Lazaridis K, Baltatzidi V, Trakas N, Koutroumpi E, Karandreas N, Tzartos SJ. Characterization of a reproducible rat EAMG model induced with various human acetylcholine receptor domains. J Neuroimmunol 2017; 303:13-21. [DOI: 10.1016/j.jneuroim.2016.12.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Revised: 12/04/2016] [Accepted: 12/05/2016] [Indexed: 01/08/2023]
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19
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Stergiou C, Lazaridis K, Zouvelou V, Tzartos J, Mantegazza R, Antozzi C, Andreetta F, Evoli A, Deymeer F, Saruhan-Direskeneli G, Durmus H, Brenner T, Vaknin A, Berrih-Aknin S, Behin A, Sharshar T, De Baets M, Losen M, Martinez-Martinez P, Kleopa KA, Zamba-Papanicolaou E, Kyriakides T, Kostera-Pruszczyk A, Szczudlik P, Szyluk B, Lavrnic D, Basta I, Peric S, Tallaksen C, Maniaol A, Gilhus NE, Casasnovas Pons C, Pitha J, Jakubíkova M, Hanisch F, Bogomolovas J, Labeit D, Labeit S, Tzartos SJ. Titin antibodies in "seronegative" myasthenia gravis--A new role for an old antigen. J Neuroimmunol 2016; 292:108-15. [PMID: 26943968 DOI: 10.1016/j.jneuroim.2016.01.018] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Accepted: 01/25/2016] [Indexed: 12/11/2022]
Abstract
Myasthenia gravis (MG) is an autoimmune disease caused by antibodies targeting the neuromuscular junction of skeletal muscles. Triple-seronegative MG (tSN-MG, without detectable AChR, MuSK and LRP4 antibodies), which accounts for ~10% of MG patients, presents a serious gap in MG diagnosis and complicates differential diagnosis of similar disorders. Several AChR antibody positive patients (AChR-MG) also have antibodies against titin, usually detected by ELISA. We have developed a very sensitive radioimmunoprecipitation assay (RIPA) for titin antibodies, by which many previously negative samples were found positive, including several from tSN-MG patients. The validity of the RIPA results was confirmed by western blots. Using this RIPA we screened 667 MG sera from 13 countries; as expected, AChR-MG patients had the highest frequency of titin antibodies (40.9%), while MuSK-MG and LRP4-MG patients were positive in 14.6% and 16.4% respectively. Most importantly, 13.4% (50/372) of the tSN-MG patients were also titin antibody positive. None of the 121 healthy controls or the 90 myopathy patients, and only 3.6% (7/193) of other neurological disease patients were positive. We thus propose that the present titin antibody RIPA is a useful tool for serological MG diagnosis of tSN patients.
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Affiliation(s)
- C Stergiou
- Hellenic Pasteur Institute, Athens, Greece; Tzartos NeuroDiagnostics, Athens, Greece
| | | | - V Zouvelou
- Neurology Department, Aeginition Hospital, Athens, Greece
| | - J Tzartos
- Hellenic Pasteur Institute, Athens, Greece; Tzartos NeuroDiagnostics, Athens, Greece
| | - R Mantegazza
- Neurological Institute "C. Besta", Milano, Italy
| | - C Antozzi
- Neurological Institute "C. Besta", Milano, Italy
| | - F Andreetta
- Neurological Institute "C. Besta", Milano, Italy
| | - A Evoli
- Institute of Neurology, Catholic University, Rome, Italy
| | - F Deymeer
- Istanbul University, Istanbul, Turkey
| | | | - H Durmus
- Istanbul University, Istanbul, Turkey
| | - T Brenner
- Hadassah Hebrew University Medical Center, Jerusalem, Israel
| | - A Vaknin
- Hadassah Hebrew University Medical Center, Jerusalem, Israel
| | | | - A Behin
- UPMC and INSERM, Paris, France
| | - T Sharshar
- Raymond Poincaré Hospital, Garches, France
| | - M De Baets
- School for Mental Health and Neuroscience, Maastricht University, The Netherlands
| | - M Losen
- School for Mental Health and Neuroscience, Maastricht University, The Netherlands
| | - P Martinez-Martinez
- School for Mental Health and Neuroscience, Maastricht University, The Netherlands
| | - K A Kleopa
- The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus
| | | | - T Kyriakides
- The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus
| | | | - P Szczudlik
- Department of Neurology, Medical University of Warsaw, Poland
| | - B Szyluk
- Department of Neurology, Medical University of Warsaw, Poland
| | - D Lavrnic
- Neurology Clinic, Clinical Center of Serbia, School of Medicine, University of Belgrade, Belgrade, Serbia
| | - I Basta
- Neurology Clinic, Clinical Center of Serbia, School of Medicine, University of Belgrade, Belgrade, Serbia
| | - S Peric
- Neurology Clinic, Clinical Center of Serbia, School of Medicine, University of Belgrade, Belgrade, Serbia
| | - C Tallaksen
- Norway Department of Neurology, Ullevaal University Hospital, Oslo, Norway; Faculty of Medicine, Olso University, Norway
| | - A Maniaol
- Norway Department of Neurology, Ullevaal University Hospital, Oslo, Norway
| | - N E Gilhus
- Department of Clinical Medicine, University of Bergen, Norway
| | | | - J Pitha
- Department of Neurology and Clinical Neuroscience Center, 1st Faculty of Medicine, Charles University and General Teaching Hospital, Prague, Czech Republic
| | - M Jakubíkova
- Department of Neurology and Clinical Neuroscience Center, 1st Faculty of Medicine, Charles University and General Teaching Hospital, Prague, Czech Republic
| | - F Hanisch
- Universitätsklinikum Halle, Halle, Germany
| | - J Bogomolovas
- Faculty of Clinical Medicine Manheim, University of Heidelberg, Germany
| | - D Labeit
- Faculty of Clinical Medicine Manheim, University of Heidelberg, Germany; Myomedix GmbH, 69151 Neckargemuend, Germany
| | - S Labeit
- Faculty of Clinical Medicine Manheim, University of Heidelberg, Germany
| | - S J Tzartos
- Hellenic Pasteur Institute, Athens, Greece; Tzartos NeuroDiagnostics, Athens, Greece.
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Arnaouteli S, Giastas P, Andreou A, Tzanodaskalaki M, Aldridge C, Tzartos SJ, Vollmer W, Eliopoulos E, Bouriotis V. Two Putative Polysaccharide Deacetylases Are Required for Osmotic Stability and Cell Shape Maintenance in Bacillus anthracis. J Biol Chem 2015; 290:13465-78. [PMID: 25825488 PMCID: PMC4505593 DOI: 10.1074/jbc.m115.640029] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2015] [Indexed: 11/26/2022] Open
Abstract
Membrane-anchored lipoproteins have a broad range of functions and play key roles in several cellular processes in Gram-positive bacteria. BA0330 and BA0331 are the only lipoproteins among the 11 known or putative polysaccharide deacetylases of Bacillus anthracis. We found that both lipoproteins exhibit unique characteristics. BA0330 and BA0331 interact with peptidoglycan, and BA0330 is important for the adaptation of the bacterium to grow in the presence of a high concentration of salt, whereas BA0331 contributes to the maintenance of a uniform cell shape. They appear not to alter the peptidoglycan structure and do not contribute to lysozyme resistance. The high resolution x-ray structure of BA0330 revealed a C-terminal domain with the typical fold of a carbohydrate esterase 4 and an N-terminal domain unique for this family, composed of a two-layered (4 + 3) β-sandwich with structural similarity to fibronectin type 3 domains. Our data suggest that BA0330 and BA0331 have a structural role in stabilizing the cell wall of B. anthracis.
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Affiliation(s)
- Sofia Arnaouteli
- From the Department of Biology, Enzyme Biotechnology Group, University of Crete, Vasilika Vouton, 70013 Heraklion, Crete, Greece
| | - Petros Giastas
- the Department of Neurobiology, Hellenic Pasteur Institute, Vasilissis Sofias 127, 11521 Athens, Greece
| | - Athina Andreou
- the Department of Biotechnology, Laboratory of Genetics, Agricultural University of Athens, Iera Odos 75, 11855 Athens, Greece
| | - Mary Tzanodaskalaki
- the Institute of Molecular Biology and Biotechnology, 70013 Heraklion, Crete, Greece
| | - Christine Aldridge
- the Institute for Cell and Molecular Biosciences, Centre for Bacterial Cell Biology, Newcastle University, NE2 4AX Newcastle upon Tyne, United Kingdom, and
| | - Socrates J Tzartos
- the Department of Neurobiology, Hellenic Pasteur Institute, Vasilissis Sofias 127, 11521 Athens, Greece, the Department of Pharmacy, University of Patras, 26504, Patras, Greece
| | - Waldemar Vollmer
- the Institute for Cell and Molecular Biosciences, Centre for Bacterial Cell Biology, Newcastle University, NE2 4AX Newcastle upon Tyne, United Kingdom, and
| | - Elias Eliopoulos
- the Department of Biotechnology, Laboratory of Genetics, Agricultural University of Athens, Iera Odos 75, 11855 Athens, Greece
| | - Vassilis Bouriotis
- From the Department of Biology, Enzyme Biotechnology Group, University of Crete, Vasilika Vouton, 70013 Heraklion, Crete, Greece, the Institute of Molecular Biology and Biotechnology, 70013 Heraklion, Crete, Greece,
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Azam L, Papakyriakou A, Zouridakis M, Giastas P, Tzartos SJ, McIntosh JM. Molecular interaction of α-conotoxin RgIA with the rat α9α10 nicotinic acetylcholine receptor. Mol Pharmacol 2015; 87:855-64. [PMID: 25740413 DOI: 10.1124/mol.114.096511] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The α9α10 nicotinic acetylcholine receptor (nAChR) was first identified in the auditory system, where it mediates synaptic transmission between efferent olivocochlear cholinergic fibers and cochlea hair cells. This receptor gained further attention due to its potential role in chronic pain and breast and lung cancers. We previously showed that α-conotoxin (α-CTx) RgIA, one of the few α9α10 selective ligands identified to date, is 300-fold less potent on human versus rat α9α10 nAChR. This species difference was conferred by only one residue in the (-), rather than (+), binding region of the α9 subunit. In light of this unexpected discovery, we sought to determine other interacting residues with α-CTx RgIA. A previous molecular modeling study, based on the structure of the homologous molluscan acetylcholine-binding protein, predicted that RgIA interacts with three residues on the α9(+) face and two residues on the α10(-) face of the α9α10 nAChR. However, mutations of these residues had little or no effect on toxin block of the α9α10 nAChR. In contrast, mutations of homologous residues in the opposing nAChR subunits (α10 Ε197, P200 and α9 T61, D121) resulted in 19- to 1700-fold loss of toxin activity. Based on the crystal structure of the extracellular domain (ECD) of human α9 nAChR, we modeled the rat α9α10 ECD and its complexes with α-CTx RgIA and acetylcholine. Our data support the interaction of α-CTx RgIA at the α10/α9 rather than the α9/α10 nAChR subunit interface, and may facilitate the development of selective ligands with therapeutic potential.
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Affiliation(s)
- Layla Azam
- Departments of Biology (L.A., J.M.M.) and Psychiatry (J.M.M.), University of Utah, Salt Lake City, Utah; George E. Wahlen Veterans Affair Medical Center, Salt Lake City, Utah (J.M.M.); National Center for Scientific Research "Demokritos," Athens, Greece (A.P.); and Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece (M.Z., P.G., S.J.T.)
| | - Athanasios Papakyriakou
- Departments of Biology (L.A., J.M.M.) and Psychiatry (J.M.M.), University of Utah, Salt Lake City, Utah; George E. Wahlen Veterans Affair Medical Center, Salt Lake City, Utah (J.M.M.); National Center for Scientific Research "Demokritos," Athens, Greece (A.P.); and Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece (M.Z., P.G., S.J.T.)
| | - Marios Zouridakis
- Departments of Biology (L.A., J.M.M.) and Psychiatry (J.M.M.), University of Utah, Salt Lake City, Utah; George E. Wahlen Veterans Affair Medical Center, Salt Lake City, Utah (J.M.M.); National Center for Scientific Research "Demokritos," Athens, Greece (A.P.); and Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece (M.Z., P.G., S.J.T.)
| | - Petros Giastas
- Departments of Biology (L.A., J.M.M.) and Psychiatry (J.M.M.), University of Utah, Salt Lake City, Utah; George E. Wahlen Veterans Affair Medical Center, Salt Lake City, Utah (J.M.M.); National Center for Scientific Research "Demokritos," Athens, Greece (A.P.); and Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece (M.Z., P.G., S.J.T.)
| | - Socrates J Tzartos
- Departments of Biology (L.A., J.M.M.) and Psychiatry (J.M.M.), University of Utah, Salt Lake City, Utah; George E. Wahlen Veterans Affair Medical Center, Salt Lake City, Utah (J.M.M.); National Center for Scientific Research "Demokritos," Athens, Greece (A.P.); and Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece (M.Z., P.G., S.J.T.)
| | - J Michael McIntosh
- Departments of Biology (L.A., J.M.M.) and Psychiatry (J.M.M.), University of Utah, Salt Lake City, Utah; George E. Wahlen Veterans Affair Medical Center, Salt Lake City, Utah (J.M.M.); National Center for Scientific Research "Demokritos," Athens, Greece (A.P.); and Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece (M.Z., P.G., S.J.T.)
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Zouridakis M, Giastas P, Zarkadas E, Chroni-Tzartou D, Bregestovski P, Tzartos SJ. Crystal structures of free and antagonist-bound states of human α9 nicotinic receptor extracellular domain. Nat Struct Mol Biol 2014; 21:976-80. [PMID: 25282151 DOI: 10.1038/nsmb.2900] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2013] [Accepted: 09/09/2014] [Indexed: 01/06/2023]
Abstract
We determined the X-ray crystal structures of the extracellular domain (ECD) of the monomeric state of human neuronal α9 nicotinic acetylcholine receptor (nAChR) and of its complexes with the antagonists methyllycaconitine and α-bungarotoxin at resolutions of 1.8 Å, 1.7 Å and 2.7 Å, respectively. The structure of the monomeric α9 ECD superimposed well with the structures of homologous proteins in pentameric assemblies, denoting native folding, despite the absence of a complementary subunit and transmembrane domain. The interaction motifs of both antagonists were similar to those in the complexes with homologous pentameric proteins, thus highlighting the major contribution of the principal side of α9 ECD to their binding. The structures revealed a functionally important β7-β10 strand interaction in α9-containing nAChRs, involving their unique Thr147, a hydration pocket similar to that of mouse α1 ECD and a membrane-facing network coordinated by the invariant Arg210.
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Affiliation(s)
- Marios Zouridakis
- Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece
| | - Petros Giastas
- Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece
| | - Eleftherios Zarkadas
- 1] Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece. [2] Department of Pharmacy, University of Patras, Rio, Greece
| | | | - Piotr Bregestovski
- INSERM UMR1106, Brain Dynamics Institute, University Aix-Marseille, Marseille, France
| | - Socrates J Tzartos
- 1] Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece. [2] Department of Pharmacy, University of Patras, Rio, Greece
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Kordas G, Lagoumintzis G, Sideris S, Poulas K, Tzartos SJ. Direct proof of the in vivo pathogenic role of the AChR autoantibodies from myasthenia gravis patients. PLoS One 2014; 9:e108327. [PMID: 25259739 PMCID: PMC4178151 DOI: 10.1371/journal.pone.0108327] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2014] [Accepted: 08/20/2014] [Indexed: 11/23/2022] Open
Abstract
Several studies have suggested that the autoantibodies (autoAbs) against muscle acetylcholine receptor (AChR) of myasthenia gravis (MG) patients are the main pathogenic factor in MG; however, this belief has not yet been confirmed with direct observations. Although animals immunized with AChR or injected with anti-AChR monoclonal Abs, or with crude human MG Ig fractions exhibit MG symptoms, the pathogenic role of isolated anti-AChR autoAbs, and, more importantly, the absence of pathogenic factor(s) in the autoAb-depleted MG sera has not yet been shown by in vivo studies. Using recombinant extracellular domains of the human AChR α and β subunits, we have isolated autoAbs from the sera of four MG patients. The ability of these isolated anti-subunit Abs and of the Ab-depleted sera to passively transfer experimental autoimmune MG in Lewis rats was investigated. We found that the isolated anti-subunit Abs were at least as efficient as the corresponding whole sera or whole Ig in causing experimental MG. Abs to both α- and β-subunit were pathogenic although the anti-α-subunit were much more efficient than the anti-β-subunit ones. Interestingly, the autoAb-depleted sera were free of pathogenic activity. The later suggests that the myasthenogenic potency of the studied anti-AChR MG sera is totally due to their anti-AChR autoAbs, and therefore selective elimination of the anti-AChR autoAbs from MG patients may be an efficient therapy for MG.
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Affiliation(s)
- Gregory Kordas
- Department of Pharmacy, University of Patras, Patras, Greece
| | | | | | - Konstantinos Poulas
- Department of Pharmacy, University of Patras, Patras, Greece
- * E-mail: (ST); (KP)
| | - Socrates J. Tzartos
- Department of Pharmacy, University of Patras, Patras, Greece
- Department of Biochemistry, Hellenic Pasteur Institute, Athens, Greece
- * E-mail: (ST); (KP)
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Tsivgoulis G, Dervenoulas G, Kokotis P, Zompola C, Tzartos JS, Tzartos SJ, Voumvourakis KI. Double seronegative myasthenia gravis with low density lipoprotein-4 (LRP4) antibodies presenting with isolated ocular symptoms. J Neurol Sci 2014; 346:328-30. [PMID: 25248951 DOI: 10.1016/j.jns.2014.09.013] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Revised: 09/04/2014] [Accepted: 09/10/2014] [Indexed: 11/17/2022]
Abstract
The detection of low density lipoprotein-4 (LRP4) antibodies in double seronegative (dSN) myasthenia gravis (MG) patients has provided new insights in the diagnosis and treatment of MG. However, there are limited data regarding the clinical presentation and treatment response in dSN MG patients with LRP4-antibodies. We present a case series of three Caucasian dSN MG patients with positive LRP4-antibodies sharing a common ethnic background that presented with isolated ocular symptoms (MGFA I). The demographic and clinical characteristics, the diagnostic work-up as well as the treatment response during a follow-up period of 12-24 months are described in detail. All patients were treated successfully with acetylcholinesterase inhibitors (AcheI) and prednisone with two exhibiting full remission of their symptoms, while the remaining exhibited mild residual diplopia. Notably, we documented no signs of generalized disease progression, while no patient required immunosuppressive treatment. In conclusion, the distinct clinical phenotype of our patients highlights the clinical relevance of screening for LRP4-antibodies in patients presenting with isolated ocular MG independent of age and gender, since it may lead to the timely diagnosis of MG and prompt initiation of effective therapy with ACheI and corticosteroids.
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Affiliation(s)
- Georgios Tsivgoulis
- Second Department of Neurology, University of Athens, School of Medicine, "Attikon" University Hospital, Athens, Greece; International Clinical Research Center, St. Anne's University Hospital in Brno, Czech Republic.
| | - Georgios Dervenoulas
- Second Department of Neurology, University of Athens, School of Medicine, "Attikon" University Hospital, Athens, Greece
| | - Panagiotis Kokotis
- Second Department of Neurology, University of Athens, School of Medicine, "Attikon" University Hospital, Athens, Greece; First Department of Neurology, University of Athens, School of Medicine, "Eginition" University Hospital, Athens, Greece
| | - Christina Zompola
- Second Department of Neurology, University of Athens, School of Medicine, "Attikon" University Hospital, Athens, Greece
| | | | - Socrates J Tzartos
- Hellenic Pasteur Institute, Athens, Greece; Tzartos NeuroDiagnostics, Athens, Greece
| | - Konstantinos I Voumvourakis
- Second Department of Neurology, University of Athens, School of Medicine, "Attikon" University Hospital, Athens, Greece
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Marino M, Maiuri MT, Di Sante G, Scuderi F, La Carpia F, Trakas N, Provenzano C, Zisimopoulou P, Ria F, Tzartos SJ, Evoli A, Bartoccioni E. T cell repertoire in DQ5-positive MuSK-positive myasthenia gravis patients. J Autoimmun 2014; 52:113-21. [DOI: 10.1016/j.jaut.2013.12.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2013] [Accepted: 12/08/2013] [Indexed: 11/26/2022]
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26
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Tsivgoulis G, Dervenoulas G, Tzartos SJ, Zompola C, Papageorgiou SG, Voumvourakis K. Double seropositive myasthenia gravis with acetylcholine receptor and lipoprotein receptor-related protein 4 antibodies. Muscle Nerve 2014; 49:930-1. [DOI: 10.1002/mus.24166] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Revised: 12/30/2013] [Accepted: 01/02/2014] [Indexed: 11/05/2022]
Affiliation(s)
- Georgios Tsivgoulis
- Second Department of Neurology; University of Athens, School of Medicine, “Attikon” University Hospital; Athens Greece
- International Clinical Research Center; St. Anne's University Hospital; Brno Czech Republic
| | - Georgios Dervenoulas
- Second Department of Neurology; University of Athens, School of Medicine, “Attikon” University Hospital; Athens Greece
| | - Socrates J. Tzartos
- Hellenic Pasteur Institute; Athens Greece
- Department of Pharmacy; University of Patras; Patras Greece
| | - Christina Zompola
- Second Department of Neurology; University of Athens, School of Medicine, “Attikon” University Hospital; Athens Greece
| | - Sokratis G. Papageorgiou
- Second Department of Neurology; University of Athens, School of Medicine, “Attikon” University Hospital; Athens Greece
| | - Konstantinos Voumvourakis
- Second Department of Neurology; University of Athens, School of Medicine, “Attikon” University Hospital; Athens Greece
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Lazaridis K, Zisimopoulou P, Giastas P, Bitzopoulou K, Evangelakou P, Sideri A, Tzartos SJ. Expression of human AChR extracellular domain mutants with improved characteristics. Int J Biol Macromol 2014; 63:210-7. [DOI: 10.1016/j.ijbiomac.2013.11.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2013] [Revised: 11/07/2013] [Accepted: 11/10/2013] [Indexed: 10/26/2022]
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Zouvelou V, Zisimopoulou P, Psimenou E, Matsigkou E, Stamboulis E, Tzartos SJ. AChR-myasthenia gravis switching to double-seropositive several years after the onset. J Neuroimmunol 2014; 267:111-2. [DOI: 10.1016/j.jneuroim.2013.12.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2013] [Revised: 12/08/2013] [Accepted: 12/17/2013] [Indexed: 11/16/2022]
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Vrolix K, Fraussen J, Losen M, Stevens J, Lazaridis K, Molenaar PC, Somers V, Bracho MA, Le Panse R, Stinissen P, Berrih-Aknin S, Maessen JG, Van Garsse L, Buurman WA, Tzartos SJ, De Baets MH, Martinez-Martinez P. Clonal heterogeneity of thymic B cells from early-onset myasthenia gravis patients with antibodies against the acetylcholine receptor. J Autoimmun 2014; 52:101-12. [PMID: 24439114 DOI: 10.1016/j.jaut.2013.12.008] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Accepted: 12/12/2013] [Indexed: 10/25/2022]
Abstract
Myasthenia gravis (MG) with antibodies against the acetylcholine receptor (AChR-MG) is considered as a prototypic autoimmune disease. The thymus is important in the pathophysiology of the disease since thymus hyperplasia is a characteristic of early-onset AChR-MG and patients often improve after thymectomy. We hypothesized that thymic B cell and antibody repertoires of AChR-MG patients differ intrinsically from those of control individuals. Using immortalization with Epstein-Barr Virus and Toll-like receptor 9 activation, we isolated and characterized monoclonal B cell lines from 5 MG patients and 8 controls. Only 2 of 570 immortalized B cell clones from MG patients produced antibodies against the AChR (both clones were from the same patient), suggesting that AChR-specific B cells are not enriched in the thymus. Surprisingly, many B cell lines from both AChR-MG and control thymus samples displayed reactivity against striated muscle proteins. Striational antibodies were produced by 15% of B cell clones from AChR-MG versus 6% in control thymus. The IgVH gene sequence analysis showed remarkable similarities, concerning VH family gene distribution, mutation frequency and CDR3 composition, between B cells of AChR-MG patients and controls. MG patients showed clear evidence of clonal B cell expansion in contrast to controls. In this latter aspect, MG resembles multiple sclerosis and clinically isolated syndrome, but differs from systemic lupus erythematosus. Our results support an antigen driven immune response in the MG thymus, but the paucity of AChR-specific B cells, in combination with the observed polyclonal expansions suggest a more diverse immune response than expected.
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Affiliation(s)
- Kathleen Vrolix
- Department of Neuroscience, School of Mental Health and Neuroscience, Faculty of Health, Medicine and Life Sciences, Maastricht University, Universiteitssingel 50, P.O. Box 616, 6200 MD Maastricht, The Netherlands
| | - Judith Fraussen
- Neuroimmunology group, Biomedical Research Institute and Transnationale Universiteit Limburg, School of Life Sciences, Hasselt University, Diepenbeek, Belgium
| | - Mario Losen
- Department of Neuroscience, School of Mental Health and Neuroscience, Faculty of Health, Medicine and Life Sciences, Maastricht University, Universiteitssingel 50, P.O. Box 616, 6200 MD Maastricht, The Netherlands
| | - Jo Stevens
- Department of Neuroscience, School of Mental Health and Neuroscience, Faculty of Health, Medicine and Life Sciences, Maastricht University, Universiteitssingel 50, P.O. Box 616, 6200 MD Maastricht, The Netherlands
| | | | - Peter C Molenaar
- Department of Neuroscience, School of Mental Health and Neuroscience, Faculty of Health, Medicine and Life Sciences, Maastricht University, Universiteitssingel 50, P.O. Box 616, 6200 MD Maastricht, The Netherlands
| | - Veerle Somers
- Neuroimmunology group, Biomedical Research Institute and Transnationale Universiteit Limburg, School of Life Sciences, Hasselt University, Diepenbeek, Belgium
| | - Maria Alma Bracho
- Centre Superior d'Investigació en Salut Pública (CSISP), Àrea de Genòmica i Salut, Conselleria de Sanitat, Generalitat Valenciana, València, Spain; Institut "Cavanilles" de Biodiversitat i Biologia Evolutiva (ICBiBE), Universitat de València, València, Spain; Centro de Investigación Biomédica en Red de Epidemiología y Salud Pública (CIBERESP), Ministerio de Ciencia e Innovación, Spain
| | - Rozen Le Panse
- UPMC UM 76/INSERM U974/CNRS UMR7215/Institute of Myology, 105 Bd de l'hôpital, Paris, France
| | - Piet Stinissen
- Neuroimmunology group, Biomedical Research Institute and Transnationale Universiteit Limburg, School of Life Sciences, Hasselt University, Diepenbeek, Belgium
| | - Sonia Berrih-Aknin
- UPMC UM 76/INSERM U974/CNRS UMR7215/Institute of Myology, 105 Bd de l'hôpital, Paris, France
| | - Jos G Maessen
- Department of Cardiothoracic Surgery, University Hospital, Maastricht, The Netherlands
| | - Leen Van Garsse
- Department of Cardiothoracic Surgery, University Hospital, Maastricht, The Netherlands
| | - Wim A Buurman
- Department of Neuroscience, School of Mental Health and Neuroscience, Faculty of Health, Medicine and Life Sciences, Maastricht University, Universiteitssingel 50, P.O. Box 616, 6200 MD Maastricht, The Netherlands
| | - Socrates J Tzartos
- Department of Biochemistry, Hellenic Pasteur Institute, GR 11521 Athens, Greece
| | - Marc H De Baets
- Department of Neuroscience, School of Mental Health and Neuroscience, Faculty of Health, Medicine and Life Sciences, Maastricht University, Universiteitssingel 50, P.O. Box 616, 6200 MD Maastricht, The Netherlands; Neuroimmunology group, Biomedical Research Institute and Transnationale Universiteit Limburg, School of Life Sciences, Hasselt University, Diepenbeek, Belgium
| | - Pilar Martinez-Martinez
- Department of Neuroscience, School of Mental Health and Neuroscience, Faculty of Health, Medicine and Life Sciences, Maastricht University, Universiteitssingel 50, P.O. Box 616, 6200 MD Maastricht, The Netherlands.
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Tzartos JS, Zisimopoulou P, Rentzos M, Karandreas N, Zouvelou V, Evangelakou P, Tsonis A, Thomaidis T, Lauria G, Andreetta F, Mantegazza R, Tzartos SJ. LRP4 antibodies in serum and CSF from amyotrophic lateral sclerosis patients. Ann Clin Transl Neurol 2013; 1:80-7. [PMID: 25356387 PMCID: PMC4212481 DOI: 10.1002/acn3.26] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2013] [Revised: 12/02/2013] [Accepted: 12/04/2013] [Indexed: 12/11/2022] Open
Abstract
Objective Amyotrophic lateral sclerosis (ALS) and myasthenia gravis (MG) are caused, respectively, by motor neuron degeneration and neuromuscular junction (NMJ) dysfunction. The membrane protein LRP4 is crucial in the development and function of motor neurons and NMJs and LRP4 autoantibodies have been recently detected in some MG patients. Because of the critical role in motor neuron function we searched for LRP4 antibodies in ALS patients. Methods We developed a cell-based assay and a radioimmunoassay and with these we studied the sera from 104 ALS patients. Results LRP4 autoantibodies were detected in sera from 24/104 (23.4%) ALS patients from Greece (12/51) and Italy (12/53), but only in 5/138 (3.6%) sera from patients with other neurological diseases and 0/40 sera from healthy controls. The presence of LRP4 autoantibodies in five of six tested patients was persistent for at least 10 months. Cerebrospinal fluid samples from six of seven tested LRP4 antibody-seropositive ALS patients were also positive. No autoantibodies to other MG autoantigens (AChR and MuSK) were detected in ALS patients. No differences in clinical pattern were seen between ALS patients with or without LRP4 antibodies. Conclusions We infer that LRP4 autoantibodies are involved in patients with neurological manifestations affecting LRP4-containing tissues and are found more frequently in ALS patients than MG patients. LRP4 antibodies may have a direct pathogenic activity in ALS by participating in the denervation process.
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Affiliation(s)
- John S Tzartos
- Hellenic Pasteur Institute Athens, Greece ; Department of Neurology, General Hospital "Red Cross" Athens, Greece
| | | | - Michael Rentzos
- Neurology Department, Aeginition Hospital, School of Medicine, National and Kapodistrian University Athens, Greece
| | - Nikos Karandreas
- Neurology Department, Aeginition Hospital, School of Medicine, National and Kapodistrian University Athens, Greece
| | - Vasiliki Zouvelou
- Neurology Department, Aeginition Hospital, School of Medicine, National and Kapodistrian University Athens, Greece
| | - Panagiota Evangelakou
- Hellenic Pasteur Institute Athens, Greece ; Department of Pharmacy, University of Patras Patras, Greece
| | - Anastasios Tsonis
- Hellenic Pasteur Institute Athens, Greece ; Department of Pharmacy, University of Patras Patras, Greece
| | - Thomas Thomaidis
- Department of Neurology, General Hospital "Red Cross" Athens, Greece
| | | | | | | | - Socrates J Tzartos
- Hellenic Pasteur Institute Athens, Greece ; Neurology Department, Aeginition Hospital, School of Medicine, National and Kapodistrian University Athens, Greece
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Zisimopoulou P, Evangelakou P, Tzartos J, Lazaridis K, Zouvelou V, Mantegazza R, Antozzi C, Andreetta F, Evoli A, Deymeer F, Saruhan-Direskeneli G, Durmus H, Brenner T, Vaknin A, Berrih-Aknin S, Frenkian Cuvelier M, Stojkovic T, DeBaets M, Losen M, Martinez-Martinez P, Kleopa KA, Zamba-Papanicolaou E, Kyriakides T, Kostera-Pruszczyk A, Szczudlik P, Szyluk B, Lavrnic D, Basta I, Peric S, Tallaksen C, Maniaol A, Tzartos SJ. A comprehensive analysis of the epidemiology and clinical characteristics of anti-LRP4 in myasthenia gravis. J Autoimmun 2013; 52:139-45. [PMID: 24373505 DOI: 10.1016/j.jaut.2013.12.004] [Citation(s) in RCA: 183] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2013] [Accepted: 12/08/2013] [Indexed: 11/29/2022]
Abstract
Double-seronegative myasthenia gravis (dSN-MG, without detectable AChR and MuSK antibodies) presents a serious gap in MG diagnosis and understanding. Recently, autoantibodies against the low-density lipoprotein receptor-related protein 4 (LRP4) have been identified in several dSN-MG sera, but with dramatic frequency variation (∼2-50%). We have developed a cell based assay (CBA) based on human LRP4 expressing HEK293 cells, for the reliable and efficient detection of LRP4 antibodies. We have screened about 800 MG patient sera from 10 countries for LRP4 antibodies. The overall frequency of LRP4-MG in the dSN-MG group (635 patients) was 18.7% but with variations among different populations (range 7-32.7%). Interestingly, we also identified double positive sera: 8/107 anti-AChR positive and 10/67 anti-MuSK positive sera also had detectable LRP4 antibodies, predominantly originating from only two of the participating groups. No LRP4 antibodies were identified in sera from 56 healthy controls tested, while 4/110 from patients with other neuroimmune diseases were positive. The clinical data, when available, for the LRP4-MG patients were then studied. At disease onset symptoms were mild (81% had MGFA grade I or II), with some identified thymic changes (32% hyperplasia, none with thymoma). On the other hand, double positive patients (AChR/LRP4-MG and MuSK/LRP4-MG) had more severe symptoms at onset compared with any single positive MG subgroup. Contrary to MuSK-MG, 27% of ocular dSN-MG patients were LRP4 antibody positive. Similarly, contrary to MuSK antibodies, which are predominantly of the IgG4 subtype, LRP4 antibodies were predominantly of the IgG1 and IgG2 subtypes. The prevalence was higher in women than in men (female/male ratio 2.5/1), with an average disease onset at ages 33.4 for females and 41.9 for males. Overall, the response of LRP4-MG patients to treatment was similar to published responses of AChR-MG rather than to MuSK-MG patients.
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Affiliation(s)
| | - P Evangelakou
- Hellenic Pasteur Institute, Athens, Greece; University of Patras, Patras, Greece
| | - J Tzartos
- Hellenic Pasteur Institute, Athens, Greece
| | | | - V Zouvelou
- Neurology Department, Aeginition Hospital, Athens, Greece
| | - R Mantegazza
- Neurological Institute "C. Besta", Milano, Italy
| | - C Antozzi
- Neurological Institute "C. Besta", Milano, Italy
| | - F Andreetta
- Neurological Institute "C. Besta", Milano, Italy
| | - A Evoli
- Institute of Neurology, Catholic University, Rome, Italy
| | - F Deymeer
- Istanbul University, Istanbul, Turkey
| | | | - H Durmus
- Istanbul University, Istanbul, Turkey
| | - T Brenner
- Hadassah Hebrew University Medical Center, Jerusalem, Israel
| | - A Vaknin
- Hadassah Hebrew University Medical Center, Jerusalem, Israel
| | | | | | | | - M DeBaets
- School for Mental Health and Neuroscience, Maastricht University, The Netherlands
| | - M Losen
- School for Mental Health and Neuroscience, Maastricht University, The Netherlands
| | - P Martinez-Martinez
- School for Mental Health and Neuroscience, Maastricht University, The Netherlands
| | - K A Kleopa
- The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus
| | | | - T Kyriakides
- The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus
| | | | - P Szczudlik
- Department of Neurology, Medical University of Warsaw, Poland
| | - B Szyluk
- Department of Neurology, Medical University of Warsaw, Poland
| | - D Lavrnic
- Serbia, Clinic of Neurology, Clinical Center of Serbia, Serbia
| | - I Basta
- Serbia, Clinic of Neurology, Clinical Center of Serbia, Serbia
| | - S Peric
- Serbia, Clinic of Neurology, Clinical Center of Serbia, Serbia
| | - C Tallaksen
- Norway Department of Neurology, Ullevaal University Hospital, Oslo, Norway
| | - A Maniaol
- Norway Department of Neurology, Ullevaal University Hospital, Oslo, Norway
| | - S J Tzartos
- Hellenic Pasteur Institute, Athens, Greece; University of Patras, Patras, Greece.
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Niarchos A, Zouridakis M, Douris V, Georgostathi A, Kalamida D, Sotiriadis A, Poulas K, Iatrou K, Tzartos SJ. Expression of a highly antigenic and native-like folded extracellular domain of the human α1 subunit of muscle nicotinic acetylcholine receptor, suitable for use in antigen specific therapies for Myasthenia Gravis. PLoS One 2013; 8:e84791. [PMID: 24376846 PMCID: PMC3869910 DOI: 10.1371/journal.pone.0084791] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2013] [Accepted: 11/25/2013] [Indexed: 11/29/2022] Open
Abstract
We describe the expression of the extracellular domain of the human α1 nicotinic acetylcholine receptor (nAChR) in lepidopteran insect cells (i-α1-ECD) and its suitability for use in antigen-specific therapies for Myasthenia Gravis (MG). Compared to the previously expressed protein in P. pastoris (y-α1-ECD), i-α1-ECD had a 2-fold increased expression yield, bound anti-nAChR monoclonal antibodies and autoantibodies from MG patients two to several-fold more efficiently and resulted in a secondary structure closer to that of the crystal structure of mouse α1-ECD. Our results indicate that i-α1-ECD is an improved protein for use in antigen-specific MG therapeutic strategies.
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Affiliation(s)
| | - Marios Zouridakis
- Department of Biochemistry, Hellenic Pasteur Institute, Athens, Greece
| | - Vassilis Douris
- Institute of Biosciences and Applications, National Centre for Scientific Research “Demokritos”, Athens, Greece
| | | | | | | | - Konstantinos Poulas
- Department of Pharmacy, University of Patras, Patras, Greece
- * E-mail: (SJT) (KP)
| | - Kostas Iatrou
- Institute of Biosciences and Applications, National Centre for Scientific Research “Demokritos”, Athens, Greece
| | - Socrates J. Tzartos
- Department of Pharmacy, University of Patras, Patras, Greece
- Department of Biochemistry, Hellenic Pasteur Institute, Athens, Greece
- * E-mail: (SJT) (KP)
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Lagoumintzis G, Zisimopoulou P, Trakas N, Grapsa E, Poulas K, Tzartos SJ. Scale up and safety parameters of antigen specific immunoadsorption of human anti-acetylcholine receptor antibodies. J Neuroimmunol 2013; 267:1-6. [PMID: 24412396 DOI: 10.1016/j.jneuroim.2013.11.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Revised: 10/25/2013] [Accepted: 11/05/2013] [Indexed: 01/17/2023]
Abstract
Myasthenia gravis is an autoimmune disease usually caused by autoantibodies against the muscle nicotinic acetylcholine receptor (nAChR). Current treatments are not specific, and thus often cause side effects. Here, we elaborate on our previous findings on antigen specific immunoadsorption towards scaling up the method as well as testing whole blood apheresis. The average percent of plasma or whole blood immunoadsorption was up to 79.5%±2.9. Moreover, neither pyrogens were co-administered nor did complement activation occur after immunoadsorption. Thus, antigen-specific apheresis of anti-AChR autoantibodies seems a safe and effective treatment for myasthenia gravis that can be scaled up for clinical testing.
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Affiliation(s)
| | - Paraskevi Zisimopoulou
- Department of Biochemistry, Hellenic Pasteur Institute, 127 Vass. Sofias Avenue, GR 11521, Athens, Greece
| | - Nikolaos Trakas
- Department of Biochemistry, Hellenic Pasteur Institute, 127 Vass. Sofias Avenue, GR 11521, Athens, Greece
| | - Eirini Grapsa
- Department of Nephrology, Aretaieion University Hospital, Athens, Greece
| | | | - Socrates J Tzartos
- Department of Biochemistry, Hellenic Pasteur Institute, 127 Vass. Sofias Avenue, GR 11521, Athens, Greece.
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Tzartos JS, Stergiou C, Kilidireas K, Zisimopoulou P, Thomaidis T, Tzartos SJ. Anti-aquaporin-1 autoantibodies in patients with neuromyelitis optica spectrum disorders. PLoS One 2013; 8:e74773. [PMID: 24086369 PMCID: PMC3781161 DOI: 10.1371/journal.pone.0074773] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2013] [Accepted: 08/07/2013] [Indexed: 12/02/2022] Open
Abstract
Autoantibodies against aquaporin-4 (AQP4), a water channel in CNS astrocytes, are detected in ∼50–80% of patients with neuromyelitis optica spectrum disorders (NMOsd), characterized by longitudinally extensive transverse myelitis (LETM) and/or optic neuritis. Although these autoantibodies present an invaluable biomarker for NMOsd and for the differential diagnosis of multiple sclerosis (MS), diagnosis of anti-AQP4-seronegative NMOsd remains challenging. We hypothesized that seronegative NMOsd patients might have autoantibodies against aquaporin-1 (AQP1), another water channel in CNS astrocytes. We initially developed a radioimmunoprecipitation assay to search for anti-AQP1 antibodies in sera from 632 individuals. Anti-AQP1 or anti-AQP4 autoantibodies were detected in 16.7% and 12%, respectively, of 348 patients with suspected NMOsd. Anti-AQP1 specificity was confirmed by competition, protein immunoblotting and ELISA assays, whereas epitope localization was studied by immunoadsorption on intact cells expressing AQP1 and peptide mapping experiments. Most anti-AQP1 autoantibodies were of the complement-activating IgG1 subclass and the majority bound to the extracellular domain of AQP1, suggesting a possible pathogenic role. Five out of 42 MS patients had anti-AQP1 antibodies, but 2 of them also had spinal cord lesions, while the anti-AQP1 antibodies in the other 3 bound to the cytoplasmic domain of AQP1. Anti-AQP1 antibodies were not detected in 100 healthy individuals or 142 patients with non-demyelinating neuroimmune diseases. Analysis of 17 anti-AQP1+/anti-AQP4- patients with suspected NMOsd showed that 5 had NMO and 11 had LETM. 12/17 of these sera bound predominantly to the extracellular AQP1 loop-Α. Overall, we found that anti-AQP1 autoantibodies are present in a subgroup of patients with chronic demyelination in the CNS and similarities with anti-AQP4-seronegative NMOsd, offering a novel potential biomarker for CNS demyelination disorders.
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Affiliation(s)
- John S. Tzartos
- Department of Biochemistry, Hellenic Pasteur Institute, Athens, Greece
- Department of Neurology, General Hospital “Red Cross", Athens, Greece
- * E-mail: (JST); (SJT)
| | - Christos Stergiou
- Department of Biochemistry, Hellenic Pasteur Institute, Athens, Greece
| | - Konstantinos Kilidireas
- Department of Neurology, Aeginition Hospital, School of Medicine, National and Kapodistrian University, Athens, Greece
| | | | - Thomas Thomaidis
- Department of Neurology, General Hospital “Red Cross", Athens, Greece
| | - Socrates J. Tzartos
- Department of Biochemistry, Hellenic Pasteur Institute, Athens, Greece
- Department of Pharmacy, University of Patras, Patras, Greece
- * E-mail: (JST); (SJT)
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Zouvelou V, Zisimopoulou P, Rentzos M, Karandreas N, Evangelakou P, Stamboulis E, Tzartos SJ. Double seronegative myasthenia gravis with anti-LRP 4 antibodies. Neuromuscul Disord 2013; 23:568-70. [DOI: 10.1016/j.nmd.2013.03.013] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2012] [Revised: 02/03/2013] [Accepted: 03/25/2013] [Indexed: 11/16/2022]
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Zisimopoulou P, Brenner T, Trakas N, Tzartos SJ. Serological diagnostics in myasthenia gravis based on novel assays and recently identified antigens. Autoimmun Rev 2013; 12:924-30. [PMID: 23537507 DOI: 10.1016/j.autrev.2013.03.002] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/12/2013] [Indexed: 10/27/2022]
Abstract
Myasthenia gravis (MG) is the most common immune-mediated disorder of the neuromuscular junction with a prevalence of 200-300/million population and its study has established paradigms for exploring other antibody-mediated diseases. Most MG patients (~85%) have autoantibodies against the muscle acetylcholine receptor (AChR-MG), whereas about 6% of MG patients have autoantibodies against the muscle specific kinase (MuSK-MG). Until recently no autoantibodies could be detected in the remaining patients (seronegative MG). Probably, the most sensitive assays for the detection of the autoantibodies in MG sera have been the radioimmunoprecipitation assays (RIPA) for both types of MG. However, with recent novel methods, not yet used routinely, it has been shown that the "seronegative" MG group includes patients with low levels of autoantibodies or of low affinity, against the known autoantigens, or even with antibodies to recently identified autoantigens. Since MG is heterogeneous in terms of pathophysiology, depending on the autoantigen targeted and on other factors (e.g. presence of thymoma), the serological tests are crucial in verifying the initial clinical diagnosis, whereas frequent measurement of autoantibody levels is important in monitoring the course of the disease and the efficacy of treatment. In addition, in AChR-MG, autoantibodies against the muscle proteins titin and ryanodin receptor have been identified; these antibodies are useful for the classification of MG, indicating the concomitant presence of thymoma, and as prognostic markers.
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Zouvelou V, Kyriazi S, Rentzos M, Belimezi M, Micheli MA, Tzartos SJ, Stamboulis E. Double-seropositive myasthenia gravis. Muscle Nerve 2013; 47:465-6. [DOI: 10.1002/mus.23645] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2012] [Revised: 08/19/2012] [Accepted: 08/21/2012] [Indexed: 11/07/2022]
Affiliation(s)
- Vasiliki Zouvelou
- Neurology Department; Aeginition Hospital; University of Athens; Athens; Greece
| | - Stavroula Kyriazi
- MRI Department; Evgenideion Hospital; University of Athens; Athens; Greece
| | - Michael Rentzos
- Neurology Department; Aeginition Hospital; University of Athens; Athens; Greece
| | - Maria Belimezi
- Department of Biochemistry; Hellenic Pasteur Institute; Athens; Greece
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Poulas K, Koutsouraki E, Kordas G, Kokla A, Tzartos SJ. Anti-MuSK- and anti-AChR-positive myasthenia gravis induced by d-penicillamine. J Neuroimmunol 2012; 250:94-8. [DOI: 10.1016/j.jneuroim.2012.05.011] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2011] [Revised: 03/17/2012] [Accepted: 05/16/2012] [Indexed: 10/28/2022]
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Zhang B, Tzartos JS, Belimezi M, Ragheb S, Bealmear B, Lewis RA, Xiong WC, Lisak RP, Tzartos SJ, Mei L. Autoantibodies to lipoprotein-related protein 4 in patients with double-seronegative myasthenia gravis. ACTA ACUST UNITED AC 2011; 69:445-51. [PMID: 22158716 DOI: 10.1001/archneurol.2011.2393] [Citation(s) in RCA: 207] [Impact Index Per Article: 15.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
OBJECTIVES To determine whether patients with myasthenia gravis (MG) have serum antibodies to lipoprotein-related protein 4 (LRP4), a newly identified receptor for agrin that is essential for neuromuscular junction formation, and to establish whether such antibodies contribute to MG pathogenesis. DESIGN Serum samples from patients with MG with known status of serum antibodies to the acetylcholine receptor (AChR) and muscle-specific kinase (MuSK) and serum samples from control subjects (healthy individuals and individuals with other diseases) were tested for antibodies to LRP4. Serum samples with such antibodies were tested to determine whether they had the ability to inhibit 2 different functions of LRP4 at the neuromuscular junction. SETTING Serum samples were collected at the Hellenic Pasteur Institute and Wayne State University. Samples were tested for LRP4 autoantibodies at Georgia Health Sciences University. Other immunoreactivities of the samples were tested at the Hellenic Pasteur Institute, Athens, Greece, or processed through University Laboratories of the Detroit Medical Center, Michigan. Patients The study included 217 patients with MG, 76 patients with other neurologic or psychiatric diseases, and 45 healthy control subjects. RESULTS Anti-LRP4 antibodies were detected in 11 of 120 patients with MG without detectable anti-AChR or anti-MuSK antibodies (double seronegative) and in 1 of 36 patients without anti-AChR antibodies but with anti-MuSK antibodies, but they were not detected in any of the 61 patients with anti-AChR antibodies. No healthy control subjects and only 2 of the 76 control patients with neurologic disease had anti-LRP4 antibodies. Serum samples from patients with MG with anti-LRP4 antibodies were able to inhibit the LRP4-agrin interaction and/or alter AChR clustering in muscle cells. CONCLUSIONS Anti-LRP4 antibodies were detected in the serum of approximately 9.2% of patients with double-seronegative MG. This frequency is intermediate compared with 2 recent studies showing anti-LRP4 antibodies in 2% and 50% of patients with double-seronegative MG from different geographic locations. Together, these observations indicate that LRP4 is another autoantigen in patients with MG, and anti-LRP4 autoantibodies may be pathogenic through different immunopathogenic processes.
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Affiliation(s)
- Bin Zhang
- Department of Neurology, Institute of Molecular Medicine and Genetics, Georgia Health Sciences University, 1120 15th St, Augusta, GA 30912, USA
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Trakas N, Zisimopoulou P, Tzartos SJ. Development of a highly sensitive diagnostic assay for muscle-specific tyrosine kinase (MuSK) autoantibodies in myasthenia gravis. J Neuroimmunol 2011; 240-241:79-86. [DOI: 10.1016/j.jneuroim.2011.09.007] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2011] [Accepted: 09/16/2011] [Indexed: 10/16/2022]
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Pavlakis PP, Alexopoulos H, Kosmidis ML, Stamboulis E, Routsias JG, Tzartos SJ, Tzioufas AG, Moutsopoulos HM, Dalakas MC. Peripheral neuropathies in Sjogren syndrome: a new reappraisal. J Neurol Neurosurg Psychiatry 2011; 82:798-802. [PMID: 21172862 DOI: 10.1136/jnnp.2010.222109] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND The prevalence of peripheral neuropathy in patients with Sjögren syndrome remains unclear owing to conflicting results in the published series, with numbers ranging from 2% to over 60% of Sjögren syndrome patients. Whether peripheral neuropathy is a feature of the systemic or glandular disease or whether it is related to a circulating antineuronal antibody remains also uncertain. METHODS The authors reviewed the records of patients with primary Sjögren syndrome (pSS), fulfilling the Revised European-American Classification Criteria, seen in their department from 1992 to 2009. The patients with previously recorded neuropathic features were re-examined clinically and electrophysiologically. Other causes of polyneuropathy were excluded. The authors also searched for circulating antineural antibodies using immunofluorescence and western blot and for antibodies against muscarinic and nicotinic acetylcholine receptors as potential biomarkers. RESULTS 509 cases met the diagnostic criteria for pSS. Among these, 44 patients were recorded as having neuropathic symptoms. After completing the evaluation, however, only nine (1.8%) had polyneuropathy with objective clinical signs and abnormal electrophysiological findings. The neuropathy was axonal in all, in five pure sensory and in four sensorimotor. The patients with peripheral neuropathy had extraglandular manifestations such as palpable purpura and vasculitis. No evidence of antineural autoimmunity was found, and no candidate biomarkers were identified. CONCLUSION Polyneuropathy is a rare manifestation of pSS occurring in 1.8% of patients. In the majority of patients, it is a late event and frequently associated with systemic disease or risk factors for lymphoma development.
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Affiliation(s)
- Pantelis P Pavlakis
- Department of Pathophysiology, Medical School, University of Athens, Athens, Greece
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42
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Stergiou C, Zisimopoulou P, Tzartos SJ. Expression of water-soluble, ligand-binding concatameric extracellular domains of the human neuronal nicotinic receptor alpha4 and beta2 subunits in the yeast Pichia pastoris: glycosylation is not required for ligand binding. J Biol Chem 2011; 286:8884-92. [PMID: 21252231 DOI: 10.1074/jbc.m110.171645] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Nicotinic acetylcholine receptors (nAChRs) are ligand-gated cation channels that are responsible for cell communication via the neurotransmitter acetylcholine. The predominant nAChR subtype in the mammalian brain with a high affinity for nicotine is composed of α4 and β2 subunits. This nAChR subtype is responsible for addiction to nicotine and is thought to be implicated in Alzheimer and Parkinson diseases and therefore presents an important target for drug design. In an effort to obtain water-soluble, ligand-binding domains of the human α4β2 nAChR for structural studies, we expressed the extracellular domains (ECDs) of these subunits in the eukaryotic expression system Pichia pastoris. The wild-type ECDs and their mutants containing the more hydrophilic Cys-loop from the snail acetylcholine-binding protein (individually expressed or coexpressed) did not demonstrate any specific interaction with ligands. We then linked the mutated ECDs with the 24-amino acid peptide (AGS)(8) and observed that the β2-24-α4 ECD concatamer, but not the α4-24-β2 one, exhibited very satisfactory water solubility and ligand binding properties. The (125)I-epibatidine and [(3)H]nicotine bound to β2-24-α4 with dissociation constants (K(d)) of 0.38 and 19 nm, respectively, close to the published values for the intact α4β2 AChR. In addition, (125)I-epibatidine binding was blocked by nicotine, cytisine, acetylcholine, and carbamylcholine with inhibition constants (K(i)) of 20.64, 3.24, 242, and 2,254 nm, respectively. Interestingly, deglycosylation of the concatamer did not affect its ligand binding properties. Furthermore, the deglycosylated β2-24-α4 ECD existed mainly in monomeric form, thus forming an appropriate material for structural studies and possibly for pharmacological evaluation of novel α4β2 nAChR-specific agonists.
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Affiliation(s)
- Christos Stergiou
- Department of Biochemistry, Hellenic Pasteur Institute, GR11521 Athens, Greece
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Lagoumintzis G, Zisimopoulou P, Kordas G, Lazaridis K, Poulas K, Tzartos SJ. Recent approaches to the development of antigen-specific immunotherapies for myasthenia gravis. Autoimmunity 2010; 43:436-45. [DOI: 10.3109/08916930903518099] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Zouridakis M, Zisimopoulou P, Poulas K, Tzartos SJ. Recent advances in understanding the structure of nicotinic acetylcholine receptors. IUBMB Life 2009; 61:407-23. [PMID: 19319967 DOI: 10.1002/iub.170] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Nicotinic acetylcholine receptors (nAChRs), members of the Cys-loop ligand-gated ion channels (LGICs) superfamily, are involved in signal transduction upon binding of the neurotransmitter acetylcholine or exogenous ligands, such as nicotine. nAChRs are pentameric assemblies of homologous subunits surrounding a central pore that gates cation flux, and are expressed at the neuromuscular junction and in the nervous system and several nonneuronal cell types. The 17 known nAChR subunits assemble into a variety of pharmacologically distinct receptor subtypes. nAChRs are implicated in a range of physiological functions and pathophysiological conditions related to muscle contraction, learning and memory, reward, motor control, arousal, and analgesia, and therefore present an important target for drug research. Such studies would be greatly facilitated by knowledge of the high-resolution structure of the nAChR. Although this information is far from complete, important progress has been made mainly based on electron microscopy studies of Torpedo nAChR and the high-resolution X-ray crystal structures of the homologous molluscan acetylcholine-binding proteins, the extracellular domain of the mouse nAChR alpha1 subunit, and two prokaryotic pentameric LGICs. Here, we review some of the latest advances in our understanding of nAChR structure and gating.
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Affiliation(s)
- Marios Zouridakis
- Department of Biochemistry, Hellenic Pasteur Institute, Athens, Greece
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45
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Tsiamalos P, Kordas G, Kokla A, Poulas K, Tzartos SJ. Epidemiological and immunological profile of muscle-specific kinase myasthenia gravis in Greece. Eur J Neurol 2009; 16:925-30. [PMID: 19374661 DOI: 10.1111/j.1468-1331.2009.02624.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
OBJECTIVES The purposes of this study were to determine the epidemiological characteristics of muscle-specific kinase-myasthenia gravis (MuSK-MG) in Greece and the IgG subclass of the anti-MuSK antibodies. METHODS This population-based study was performed on MuSK-MG patients in Greece between 1 January 1986 and 30 June 2006. Epidemiological and clinical data for 33 patients were collected. In addition, the distribution of anti-MuSK IgG autoantibody subclasses in the sera of 14 patients was determined by immunoprecipitation. RESULTS The average annual incidence was 0.32 patients/million population/year. On 1st July 2006, there were 33 prevalent cases, giving a point prevalence rate of 2.92/million (women 4.56 and men 1.25). In females, onset of MuSK-MG occurred after the age of 30, whilst, in males, the disease appears in any decade. The female:male incidence ratio was 3.33:1, whilst the prevalence ratio was 3.65:1. Most patients presented with involvement of the facial and bulbar muscles. Amongst about 800 MG patients seropositive for antibodies against either the AChR or MuSK, one patient was found to be seropositive for anti-MuSK antibodies and ambiguous for anti-acetylcholine receptor (anti-AChR) antibodies. The vast majority of anti-MuSK antibodies were IgG4, whilst total IgG4 levels in these patients were similar to those in two healthy controls. CONCLUSIONS The incidence and prevalence of MuSK-MG in Greece are amongst the highest reported previously for other countries. MuSK-MG in Greece affects both sexes, but mainly females. The main epidemiological indices were calculated. The vast majority of anti-MuSK antibodies were IgG4.
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Affiliation(s)
- P Tsiamalos
- Department of Pharmacy, University of Patras, Patras, Greece
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Zouridakis M, Zisimopoulou P, Eliopoulos E, Poulas K, Tzartos SJ. Design and expression of human alpha7 nicotinic acetylcholine receptor extracellular domain mutants with enhanced solubility and ligand-binding properties. Biochim Biophys Acta 2008; 1794:355-66. [PMID: 19059502 DOI: 10.1016/j.bbapap.2008.11.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2008] [Revised: 11/02/2008] [Accepted: 11/04/2008] [Indexed: 11/25/2022]
Abstract
In order to facilitate structural studies of the extracellular domain (ECD) of human alpha7 nicotinic acetylcholine receptor (nAChR), we designed several mutants, since the wild-type-ECD forms large oligomers and microaggregates, and expressed them in the yeast Pichia pastoris. Mutant design was based on a 3D model of human alpha7-nAChR-ECD, constructed using as templates the X-ray crystal structure of the homologous acetylcholine-binding protein (AChBP) and the electron microscopy structure of the Torpedo alpha-nAChR-ECD. At least one mutant, mut10, carrying six single-point mutations (Phe3Tyr, Val69Thr, Cys116Ser, Ile165Thr, Val177Thr, Phe187Tyr) and the replacement of its Cys-loop with the corresponding and more hydrophilic AChBP Cys-loop, was expressed with a 4-fold higher expression yield (1.2 mg/L) than the wild-type alpha7-ECD, existing exclusively as a soluble oligomeric, probably pentameric, form, at concentrations up to at least 10 mg/mL, as judged by gel filtration and dynamic light scattering. This mutant displayed a significantly improved (125)I-alpha-bungarotoxin-binding affinity (K(d)=24 nM) compared to the wild-type-ECD (K(d)=70 nM), the binding being inhibited by unlabelled alpha-bungarotoxin, d-tubocurarine or nicotine (K(i) of 21.5 nM, 127 microM and 17.5 mM, respectively). Circular dichroism studies of mut10 revealed (a) a similar secondary structure composition ( approximately 5% alpha-helix, approximately 45% beta-sheet) to that of the AChBP, Torpedo alpha-nAChR-ECD, and mouse alpha1-nAChR-ECD, (b) a well-defined tertiary structure and (c) binding of small cholinergic ligands at micromolar concentrations. Furthermore, electron microscopy showed well-assembled, probably pentameric, particles of mut10. Finally, since deglycosylation did not alter its solubility or ligand-binding properties, mut10, in either its glycosylated or deglycosylated form, is a promising alpha7-ECD mutant for structural studies, useful for the rational drug design to treat alpha7-nAChR-related diseases.
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Affiliation(s)
- Marios Zouridakis
- Department of Biochemistry, Hellenic Pasteur Institute, 127, GR11521, Athens, Greece
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Yi HJ, Chae CS, So JS, Tzartos SJ, Souroujon MC, Fuchs S, Im SH. Suppression of experimental myasthenia gravis by a B-cell epitope-free recombinant acetylcholine receptor. Mol Immunol 2008; 46:192-201. [DOI: 10.1016/j.molimm.2008.08.264] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2008] [Revised: 07/31/2008] [Accepted: 08/05/2008] [Indexed: 11/16/2022]
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Tzartos SJ, Bitzopoulou K, Gavra I, Kordas G, Jacobson L, Kostelidou K, Lagoumintzis G, Lazos O, Poulas K, Sideris S, Sotiriadis A, Trakas N, Zisimopoulou P. Antigen-specific apheresis of pathogenic autoantibodies from myasthenia gravis sera. Ann N Y Acad Sci 2008; 1132:291-9. [PMID: 18567880 DOI: 10.1196/annals.1405.017] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Myasthenia gravis (MG) is usually caused by autoantibodies against muscle nicotinic acetylcholine receptor (AChR), which is composed of five subunits (alpha(2)betagammadelta or alpha(2)betaepsilondelta). Current treatments, including plasmapheresis, are nonspecific, causing several side effects. We aim to develop an antigen-specific alternative to plasmapheresis, since the latter removes indispensable plasma components in addition to anti-AChR antibodies. We are developing a method for the selective depletion of the anti-AChR autoantibodies from patients' plasma through the construction of "immunoadsorbent" columns carrying AChR domains. We have expressed the extracellular domains (ECDs, amino acids approximately 1-210/220) of all human muscle AChR subunits in Pichia pastoris and, in preliminary experiments, in E. coli. The ECDs were immobilized (individually or mixed) on Sepharose beads, producing Sepharose-ECD columns, which were tested for their immunoadsorbing capacity on MG sera and shown to specifically eliminate major autoantibody fractions from several MG sera. The immobilized ECDs remained stable and did not dissociate from their matrix after incubation with serum, whereas the procedure was neither toxic nor immunogenic in two experimental rabbits. Testing the intact or antibody-depleted MG sera and the affinity purified autoantibodies showed that both the intact sera and the purified autoantibodies, but not the antibody-depleted sera, could induce AChR loss in cell cultures and experimental MG in rats. This preliminary study suggests that the myasthenic potency of MG sera is entirely due to their anti-AChR antibodies and therefore their depletion should be of therapeutic value. We conclude that ECD-mediated immunoadsorption can be used as an efficient, antigen-specific therapy for MG.
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Konstantakaki M, Tzartos SJ, Poulas K, Eliopoulos E. Model of the extracellular domain of the human alpha7 nAChR based on the crystal structure of the mouse alpha1 nAChR extracellular domain. J Mol Graph Model 2008; 26:1333-7. [PMID: 18329305 DOI: 10.1016/j.jmgm.2008.01.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2007] [Revised: 01/17/2008] [Accepted: 01/23/2008] [Indexed: 10/22/2022]
Abstract
Neuronal nicotinic acetylcholine receptors (nAChRs) are important therapeutic targets for various diseases, including Alzheimer's disease, Parkinson's disease, and schizophrenia, as well as for cessation of smoking. Based on the recently determined crystal structure of the extracellular domain (ECD) of the mouse nAChR alpha1 subunit complexed with alpha-bungarotoxin at 1.94A resolution, we have constructed three-dimensional models of the ECD of the monomer, homodimer, and homopentamer of the human alpha7 nAChR and investigated in detail the interface between the two alpha7 subunits. The docking of the agonist in the ligand-binding pocket of the human alpha7 dimer was also performed and found consistent with results from labeling and mutagenesis experiments. Since the nAChR ligand-binding site is a useful target for mutagenesis studies and the rational design of drugs against diseases, these models provide useful information for future work.
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Affiliation(s)
- Maria Konstantakaki
- Department of Agricultural Biotechnology, Agricultural University of Athens, 75, Iera Odos, Votanikos, GR11855, Athens, Greece
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Zouridakis M, Kostelidou K, Sotiriadis A, Stergiou C, Eliopoulos E, Poulas K, Tzartos SJ. Circular dichroism studies of extracellular domains of human nicotinic acetylcholine receptors provide an insight into their structure. Int J Biol Macromol 2007; 41:423-9. [PMID: 17659334 DOI: 10.1016/j.ijbiomac.2007.05.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2007] [Revised: 05/31/2007] [Accepted: 05/31/2007] [Indexed: 11/26/2022]
Abstract
The extracellular domains (ECDs) of human nicotinic acetylcholine receptors (nAChRs) are of major pharmacological interest as drug targets in the autoimmune disease myasthenia gravis and in various neurological disorders. We have previously expressed and purified the human muscle alpha1-, beta1-, gamma- and epsilon-nAChR-ECDs, as well as the wild type and a mutant of neuronal alpha7-ECD, in yeast Pichia pastoris. The far-UV circular dichroism (CD) studies of these ECDs, presented here, revealed a major prevalence of beta-sheet ( approximately 40%) and a small proportion of alpha-helical ( approximately 5%) structure for all ECDs, in good agreement with the secondary structure composition of the Torpedo muscle-type nAChR-ECDs and in less, but considerable, agreement with that of the homologous invertebrate acetylcholine-binding proteins (AChBPs). The near-UV CD studies of these nAChR-ECDs indicated well-defined tertiary structures, as was previously suggested by biochemical and immunochemical studies. Furthermore, the binding of cholinergic ligands to the mutant of alpha7-ECD resulted in no changes in its secondary structure, but revealed significant local conformational changes. Our present studies probe the structure of human nAChR-ECDs for the first time and further suggest that our expressed proteins fold to a near-native conformation, thus being suitable for further structural studies.
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Affiliation(s)
- Marios Zouridakis
- Department of Biochemistry, Hellenic Pasteur Institute, 127, Vas. Sofias Ave., GR11521 Athens, Greece
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