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Pharmacological Screening of Venoms from Five Brazilian Micrurus Species on Different Ion Channels. Int J Mol Sci 2022; 23:ijms23147714. [PMID: 35887062 PMCID: PMC9318628 DOI: 10.3390/ijms23147714] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 07/05/2022] [Accepted: 07/07/2022] [Indexed: 12/05/2022] Open
Abstract
Coral snake venoms from the Micrurus genus are a natural library of components with multiple targets, yet are poorly explored. In Brazil, 34 Micrurus species are currently described, and just a few have been investigated for their venom activities. Micrurus venoms are composed mainly of phospholipases A2 and three-finger toxins, which are responsible for neuromuscular blockade—the main envenomation outcome in humans. Beyond these two major toxin families, minor components are also important for the global venom activity, including Kunitz-peptides, serine proteases, 5′ nucleotidases, among others. In the present study, we used the two-microelectrode voltage clamp technique to explore the crude venom activities of five different Micrurus species from the south and southeast of Brazil: M. altirostris, M. corallinus, M. frontalis, M. carvalhoi and M. decoratus. All five venoms induced full inhibition of the muscle-type α1β1δε nAChR with different levels of reversibility. We found M. altirostris and M. frontalis venoms acting as partial inhibitors of the neuronal-type α7 nAChR with an interesting subsequent potentiation after one washout. We discovered that M. altirostris and M. corallinus venoms modulate the α1β2 GABAAR. Interestingly, the screening on KV1.3 showed that all five Micrurus venoms act as inhibitors, being totally reversible after the washout. Since this activity seems to be conserved among different species, we hypothesized that the Micrurus venoms may rely on potassium channel inhibitory activity as an important feature of their envenomation strategy. Finally, tests on NaV1.2 and NaV1.4 showed that these channels do not seem to be targeted by Micrurus venoms. In summary, the venoms tested are multifunctional, each of them acting on at least two different types of targets.
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Tsetlin V, Haufe Y, Safronova V, Serov D, Shadamarshan P, Son L, Shelukhina I, Kudryavtsev D, Kryukova E, Kasheverov I, Nicke A, Utkin Y. Interaction of α9α10 Nicotinic Receptors With Peptides and Proteins From Animal Venoms. Front Cell Neurosci 2022; 15:765541. [PMID: 35002625 PMCID: PMC8732759 DOI: 10.3389/fncel.2021.765541] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Accepted: 11/15/2021] [Indexed: 12/13/2022] Open
Abstract
Unlike most neuronal nicotinic acetylcholine receptor (nAChR) subunits, α7, α9, and α10 subunits are able to form functional homo- or heteromeric receptors without any β subunits. While the α7 subtype is widely distributed in the mammalian brain and several peripheral tissues, α9 and α9α10 nAChRs are mainly found in the cochlea and immune cells. α-Conotoxins that specifically block the α9α10 receptor showed anti-nociceptive and anti-hyperalgesic effects in animal models. Hence, this subtype is considered a drug target for analgesics. In contrast to the α9α10-selective α-conotoxins, the three-finger toxin α-bungarotoxin inhibits muscle-type and α7 nAChRs in addition to α9α10 nAChRs. However, the selectivity of α-neurotoxins at the α9α10 subtype was less intensively investigated. Here, we compared the potencies of α-conotoxins and α-neurotoxins at the human α9α10 nAChR by two-electrode voltage clamp analysis upon expression in Xenopus oocytes. In addition, we analyzed effects of several α9α10-selective α-conotoxins on mouse granulocytes from bone marrow to identify possible physiological functions of the α9α10 nAChR subtype in these cells. The α-conotoxin-induced IL-10 release was measured upon LPS-stimulation. We found that α-conotoxins RgIA, PeIA, and Vc1.1 enhance the IL-10 expression in granulocytes which might explain the known anti-inflammatory and associated analgesic activities of α9α10-selective α-conotoxins. Furthermore, we show that two long-chain α-neurotoxins from the cobra Naja melanoleuca venom that were earlier shown to bind to muscle-type and α7 nAChRs, also inhibit the α9α10 subtype at nanomolar concentrations with one of them showing a significantly slower dissociation from this receptor than α-bungarotoxin.
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Affiliation(s)
- Victor Tsetlin
- Department of Molecular Neuroimmune Signaling, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - Yves Haufe
- Faculty of Medicine, Walther Straub Institute of Pharmacology and Toxicology, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Valentina Safronova
- Laboratory of Cellular Neurobiology, Institute of Cell Biophysics, Russian Academy of Sciences, Pushchino, Russia
| | - Dmitriy Serov
- Laboratory of Cellular Neurobiology, Institute of Cell Biophysics, Russian Academy of Sciences, Pushchino, Russia
| | - PranavKumar Shadamarshan
- Faculty of Medicine, Walther Straub Institute of Pharmacology and Toxicology, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Lina Son
- Department of Molecular Neuroimmune Signaling, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - Irina Shelukhina
- Department of Molecular Neuroimmune Signaling, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - Denis Kudryavtsev
- Department of Molecular Neuroimmune Signaling, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - Elena Kryukova
- Department of Molecular Neuroimmune Signaling, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - Igor Kasheverov
- Department of Molecular Neuroimmune Signaling, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - Annette Nicke
- Faculty of Medicine, Walther Straub Institute of Pharmacology and Toxicology, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Yuri Utkin
- Department of Molecular Neuroimmune Signaling, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
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Matsumoto A, Agbariah W, Nolte SS, Andrawos R, Levi H, Sabbah S, Yonehara K. Direction selectivity in retinal bipolar cell axon terminals. Neuron 2021; 109:2928-2942.e8. [PMID: 34390651 PMCID: PMC8478419 DOI: 10.1016/j.neuron.2021.07.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 06/18/2021] [Accepted: 07/09/2021] [Indexed: 12/20/2022]
Abstract
The ability to encode the direction of image motion is fundamental to our sense of vision. Direction selectivity along the four cardinal directions is thought to originate in direction-selective ganglion cells (DSGCs) because of directionally tuned GABAergic suppression by starburst cells. Here, by utilizing two-photon glutamate imaging to measure synaptic release, we reveal that direction selectivity along all four directions arises earlier than expected at bipolar cell outputs. Individual bipolar cells contained four distinct populations of axon terminal boutons with different preferred directions. We further show that this bouton-specific tuning relies on cholinergic excitation from starburst cells and GABAergic inhibition from wide-field amacrine cells. DSGCs received both tuned directionally aligned inputs and untuned inputs from among heterogeneously tuned glutamatergic bouton populations. Thus, directional tuning in the excitatory visual pathway is incrementally refined at the bipolar cell axon terminals and their recipient DSGC dendrites by two different neurotransmitters co-released from starburst cells. Cardinal direction selectivity emerges at types 7 and 2 bipolar cell axon terminals Starburst amacrine cells are necessary for direction selectivity in bipolar cells Cholinergic excitation and GABAergic inhibition are integrated at axon terminals Direction-selective ganglion cells receive directionally aligned glutamate inputs
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Affiliation(s)
- Akihiro Matsumoto
- Danish Research Institute of Translational Neuroscience - DANDRITE, Nordic-EMBL Partnership for Molecular Medicine, Department of Biomedicine, Aarhus University, Ole Worms Allé 8, 8000 Aarhus C, Denmark
| | - Weaam Agbariah
- Department of Medical Neurobiology, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 9112102, Israel
| | - Stella Solveig Nolte
- Danish Research Institute of Translational Neuroscience - DANDRITE, Nordic-EMBL Partnership for Molecular Medicine, Department of Biomedicine, Aarhus University, Ole Worms Allé 8, 8000 Aarhus C, Denmark
| | - Rawan Andrawos
- Department of Medical Neurobiology, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 9112102, Israel
| | - Hadara Levi
- Department of Medical Neurobiology, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 9112102, Israel
| | - Shai Sabbah
- Department of Medical Neurobiology, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem 9112102, Israel.
| | - Keisuke Yonehara
- Danish Research Institute of Translational Neuroscience - DANDRITE, Nordic-EMBL Partnership for Molecular Medicine, Department of Biomedicine, Aarhus University, Ole Worms Allé 8, 8000 Aarhus C, Denmark.
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Son L, Kryukova E, Ziganshin R, Andreeva T, Kudryavtsev D, Kasheverov I, Tsetlin V, Utkin Y. Novel Three-Finger Neurotoxins from Naja melanoleuca Cobra Venom Interact with GABA A and Nicotinic Acetylcholine Receptors. Toxins (Basel) 2021; 13:toxins13020164. [PMID: 33672715 PMCID: PMC7924340 DOI: 10.3390/toxins13020164] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Revised: 02/16/2021] [Accepted: 02/17/2021] [Indexed: 02/08/2023] Open
Abstract
Cobra venoms contain three-finger toxins (TFT) including α-neurotoxins efficiently binding nicotinic acetylcholine receptors (nAChRs). As shown recently, several TFTs block GABAA receptors (GABAARs) with different efficacy, an important role of the TFTs central loop in binding to these receptors being demonstrated. We supposed that the positive charge (Arg36) in this loop of α-cobratoxin may explain its high affinity to GABAAR and here studied α-neurotoxins from African cobra N. melanoleuca venom for their ability to interact with GABAARs and nAChRs. Three α-neurotoxins, close homologues of the known N. melanoleuca long neurotoxins 1 and 2, were isolated and sequenced. Their analysis on Torpedocalifornica and α7 nAChRs, as well as on acetylcholine binding proteins and on several subtypes of GABAARs, showed that all toxins interacted with the GABAAR much weaker than with the nAChR: one neurotoxin was almost as active as α-cobratoxin, while others manifested lower activity. The earlier hypothesis about the essential role of Arg36 as the determinant of high affinity to GABAAR was not confirmed, but the results obtained suggest that the toxin loop III may contribute to the efficient interaction of some long-chain neurotoxins with GABAAR. One of isolated toxins manifested different affinity to two binding sites on Torpedo nAChR.
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Affiliation(s)
- Lina Son
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, ul. Miklukho-Maklaya 16/10, 117997 Moscow, Russia; (L.S.); (E.K.); (R.Z.); (T.A.); (D.K.); (I.K.); (V.T.)
- Moscow Institute of Physics and Technology, 141700 Dolgoprudny, Russia
| | - Elena Kryukova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, ul. Miklukho-Maklaya 16/10, 117997 Moscow, Russia; (L.S.); (E.K.); (R.Z.); (T.A.); (D.K.); (I.K.); (V.T.)
| | - Rustam Ziganshin
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, ul. Miklukho-Maklaya 16/10, 117997 Moscow, Russia; (L.S.); (E.K.); (R.Z.); (T.A.); (D.K.); (I.K.); (V.T.)
| | - Tatyana Andreeva
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, ul. Miklukho-Maklaya 16/10, 117997 Moscow, Russia; (L.S.); (E.K.); (R.Z.); (T.A.); (D.K.); (I.K.); (V.T.)
| | - Denis Kudryavtsev
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, ul. Miklukho-Maklaya 16/10, 117997 Moscow, Russia; (L.S.); (E.K.); (R.Z.); (T.A.); (D.K.); (I.K.); (V.T.)
| | - Igor Kasheverov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, ul. Miklukho-Maklaya 16/10, 117997 Moscow, Russia; (L.S.); (E.K.); (R.Z.); (T.A.); (D.K.); (I.K.); (V.T.)
- Institute of Molecular Medicine, Sechenov First Moscow State Medical University, ul. Trubetskaya 8, bld. 2, 119991 Moscow, Russia
| | - Victor Tsetlin
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, ul. Miklukho-Maklaya 16/10, 117997 Moscow, Russia; (L.S.); (E.K.); (R.Z.); (T.A.); (D.K.); (I.K.); (V.T.)
| | - Yuri Utkin
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, ul. Miklukho-Maklaya 16/10, 117997 Moscow, Russia; (L.S.); (E.K.); (R.Z.); (T.A.); (D.K.); (I.K.); (V.T.)
- Correspondence: ; Tel.: +7-495-3366522
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Lin B, Zhang JR, Lu HJ, Zhao L, Chen J, Zhang HF, Wei XS, Zhang LY, Wu XB, Lee WH. Immunoreactivity and neutralization study of Chinese Bungarus multicinctus antivenin and lab-prepared anti-bungarotoxin antisera towards purified bungarotoxins and snake venoms. PLoS Negl Trop Dis 2020; 14:e0008873. [PMID: 33253321 PMCID: PMC7728252 DOI: 10.1371/journal.pntd.0008873] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 12/10/2020] [Accepted: 10/12/2020] [Indexed: 12/25/2022] Open
Abstract
Bungarus multicinctus is the most venomous snake distributed in China and neighboring countries of Myanmar, Laos, north Vietnam and Thailand. The high mortality rate of B. multicinctus envenomation is attributed to the lethal components of α-, β-, γ- and κ- bungarotoxins contained in the venom. Although anti-B. multicinctus sera were produced in Shanghai, Taiwan and Vietnam, the most widely clinic used product was term as B. multicinctus antivenin and manufactured by Shanghai Serum Bio-technology Co. Ltd. In the present investigation, high purity α-, β- and γ-bungarotoxins were separately isolated from B. multicinctus crude venom. Rabbit anti- α-, β- and γ-bungarotoxin antisera were prepared by common methods, respectively. LD50 values of α-, β- and γ-bungarotoxins were systematically determined via three administration pathways (intraperitoneal, intramuscular and intravenous injections) in Kunming mice. LD50 values of β-bungarotoxin were closely related with injection routines but those of both α- and γ-bungarotoxins were not dependent on the injection routines. Commercial B. multicinctus antivenin showed strong immunoreaction with high molecular weight fractions of the B. multicinctus but weakly recognized low molecular weight fractions like α- and γ-bungarotoxins. Although B. multicinctus antivenin showed immunoreaction with high molecular weight fractions of Bungarus fasciatus, Naja atra, Ophiophagus hannah venoms but the antivenin only demonstrated animal protection efficacy against O. hannah venom. These results indicated that the high molecular weight fractions of the O. hannah played an important role in venom lethality but those of B. fasciatus and N. atra did not have such a role.
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Affiliation(s)
- Bo Lin
- College of Life Sciences, Anhui Normal University, Wuhu, Anhui, China
- Key Laboratory of Animal Models and Human Disease Mechanisms of The Chinese Academy of Sciences/Key Laboratory of Bioactive Peptides of Yunnan Province, Kunming Institute of Zoology, the Chinese Academy of Sciences, Kunming, Yunnan, China
| | - Jia-Rui Zhang
- Nanshan School, Guangzhou Medical University, Guangzhou, Guandong, China
| | - Hui-Juan Lu
- Key Laboratory of Animal Models and Human Disease Mechanisms of The Chinese Academy of Sciences/Key Laboratory of Bioactive Peptides of Yunnan Province, Kunming Institute of Zoology, the Chinese Academy of Sciences, Kunming, Yunnan, China
| | - Lin Zhao
- College of Life Sciences, Anhui Normal University, Wuhu, Anhui, China
- Key Laboratory of Animal Models and Human Disease Mechanisms of The Chinese Academy of Sciences/Key Laboratory of Bioactive Peptides of Yunnan Province, Kunming Institute of Zoology, the Chinese Academy of Sciences, Kunming, Yunnan, China
| | - Jing Chen
- Key Laboratory of Animal Models and Human Disease Mechanisms of The Chinese Academy of Sciences/Key Laboratory of Bioactive Peptides of Yunnan Province, Kunming Institute of Zoology, the Chinese Academy of Sciences, Kunming, Yunnan, China
- School of Life and Pharmaceutical Sciences, Hainan University, Haikou, Hainan, China
| | - Hong-Fei Zhang
- Key Laboratory of Animal Models and Human Disease Mechanisms of The Chinese Academy of Sciences/Key Laboratory of Bioactive Peptides of Yunnan Province, Kunming Institute of Zoology, the Chinese Academy of Sciences, Kunming, Yunnan, China
| | - Xue-Song Wei
- College of Life Sciences, Anhui Normal University, Wuhu, Anhui, China
- Key Laboratory of Animal Models and Human Disease Mechanisms of The Chinese Academy of Sciences/Key Laboratory of Bioactive Peptides of Yunnan Province, Kunming Institute of Zoology, the Chinese Academy of Sciences, Kunming, Yunnan, China
| | - Liang-Yu Zhang
- Key Laboratory of Animal Models and Human Disease Mechanisms of The Chinese Academy of Sciences/Key Laboratory of Bioactive Peptides of Yunnan Province, Kunming Institute of Zoology, the Chinese Academy of Sciences, Kunming, Yunnan, China
| | - Xiao-Bing Wu
- College of Life Sciences, Anhui Normal University, Wuhu, Anhui, China
| | - Wen-Hui Lee
- Key Laboratory of Animal Models and Human Disease Mechanisms of The Chinese Academy of Sciences/Key Laboratory of Bioactive Peptides of Yunnan Province, Kunming Institute of Zoology, the Chinese Academy of Sciences, Kunming, Yunnan, China
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Nirthanan S. Snake three-finger α-neurotoxins and nicotinic acetylcholine receptors: molecules, mechanisms and medicine. Biochem Pharmacol 2020; 181:114168. [PMID: 32710970 DOI: 10.1016/j.bcp.2020.114168] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 07/20/2020] [Accepted: 07/20/2020] [Indexed: 12/13/2022]
Abstract
Snake venom three-finger α-neurotoxins (α-3FNTx) act on postsynaptic nicotinic acetylcholine receptors (nAChRs) at the neuromuscular junction (NMJ) to produce skeletal muscle paralysis. The discovery of the archetypal α-bungarotoxin (α-BgTx), almost six decades ago, exponentially expanded our knowledge of membrane receptors and ion channels. This included the localisation, isolation and characterization of the first receptor (nAChR); and by extension, the pathophysiology and pharmacology of neuromuscular transmission and associated pathologies such as myasthenia gravis, as well as our understanding of the role of α-3FNTxs in snakebite envenomation leading to novel concepts of targeted treatment. Subsequent studies on a variety of animal venoms have yielded a plethora of novel toxins that have revolutionized molecular biomedicine and advanced drug discovery from bench to bedside. This review provides an overview of nAChRs and their subtypes, classification of α-3FNTxs and the challenges of typifying an increasing arsenal of structurally and functionally unique toxins, and the three-finger protein (3FP) fold in the context of the uPAR/Ly6/CD59/snake toxin superfamily. The pharmacology of snake α-3FNTxs including their mechanisms of neuromuscular blockade, variations in reversibility of nAChR interactions, specificity for nAChR subtypes or for distinct ligand-binding interfaces within a subtype and the role of α-3FNTxs in neurotoxic envenomation are also detailed. Lastly, a reconciliation of structure-function relationships between α-3FNTx and nAChRs, derived from historical mutational and biochemical studies and emerging atomic level structures of nAChR models in complex with α-3FNTxs is discussed.
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Affiliation(s)
- Selvanayagam Nirthanan
- School of Medical Science, Griffith Health Group, Griffith University, Gold Coast, Queensland, Australia.
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7
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Tsetlin VI, Kasheverov IE, Utkin YN. Three-finger proteins from snakes and humans acting on nicotinic receptors: Old and new. J Neurochem 2020; 158:1223-1235. [PMID: 32648941 DOI: 10.1111/jnc.15123] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2020] [Revised: 06/25/2020] [Accepted: 07/06/2020] [Indexed: 12/12/2022]
Abstract
The first toxin to give rise to the three-finger protein (TFP) family was α-bungarotoxin (α-Bgt) from Bungarus multicinctus krait venom. α-Bgt was crucial for research on nicotinic acetylcholine receptors (nAChRs), and in this Review article we focus on present data for snake venom TFPs and those of the Ly6/uPAR family from mammalians (membrane-bound Lynx1 and secreted SLURP-1) interacting with nAChRs. Recently isolated from Bungarus candidus venom, αδ-bungarotoxins differ from α-Bgt: they bind more reversibly and distinguish two binding sites in Torpedo californica nAChR. Naja kaouthia α-cobratoxin, classical blocker of nAChRs, was shown to inhibit certain GABA-A receptor subtypes, whereas α-cobratoxin dimer with 2 intermolecular disulfides has a novel type of 3D structure. Non-conventional toxin WTX has additional 5th disulfide not in the central loop, as α-Bgt, but in the N-terminal loop, like all Ly6/uPAR proteins, and inhibits α7 and Torpedo nAChRs. A water-soluble form of Lynx1, ws-Lynx1, was expressed in E. coli, its 1 H-NMR structure and binding to several nAChRs determined. For SLURP-1, similar information was obtained with its recombinant analogue rSLURP-1. A common feature of ws-Lynx1, rSLURP-1, and WTX is their activity against nAChRs and muscarinic acetylcholine receptors. Synthetic SLURP-1, identical to the natural protein, demonstrated some differences from rSLURP-1 in distinguishing nAChR subtypes. The loop II fragment of the Lynx1 was synthesized having the same µM affinity for the Torpedo nAChR as ws-Lynx1. This review illustrates the productivity of parallel research of nAChR interactions with the two TFP groups.
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Affiliation(s)
- Victor I Tsetlin
- Department of Molecular Neuroimmune Signalling, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russian Federation.,PhysBio of MePhi, Moscow, Russian Federation
| | - Igor E Kasheverov
- Department of Molecular Neuroimmune Signalling, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russian Federation.,Sechenov First Moscow State Medical University, Institute of Molecular Medicine, Moscow, Russian Federation
| | - Yuri N Utkin
- Department of Molecular Neuroimmune Signalling, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russian Federation
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8
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Post Y, Puschhof J, Beumer J, Kerkkamp HM, de Bakker MAG, Slagboom J, de Barbanson B, Wevers NR, Spijkers XM, Olivier T, Kazandjian TD, Ainsworth S, Iglesias CL, van de Wetering WJ, Heinz MC, van Ineveld RL, van Kleef RGDM, Begthel H, Korving J, Bar-Ephraim YE, Getreuer W, Rios AC, Westerink RHS, Snippert HJG, van Oudenaarden A, Peters PJ, Vonk FJ, Kool J, Richardson MK, Casewell NR, Clevers H. Snake Venom Gland Organoids. Cell 2020; 180:233-247.e21. [PMID: 31978343 DOI: 10.1016/j.cell.2019.11.038] [Citation(s) in RCA: 63] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2019] [Revised: 10/29/2019] [Accepted: 11/27/2019] [Indexed: 12/12/2022]
Abstract
Wnt dependency and Lgr5 expression define multiple mammalian epithelial stem cell types. Under defined growth factor conditions, such adult stem cells (ASCs) grow as 3D organoids that recapitulate essential features of the pertinent epithelium. Here, we establish long-term expanding venom gland organoids from several snake species. The newly assembled transcriptome of the Cape coral snake reveals that organoids express high levels of toxin transcripts. Single-cell RNA sequencing of both organoids and primary tissue identifies distinct venom-expressing cell types as well as proliferative cells expressing homologs of known mammalian stem cell markers. A hard-wired regional heterogeneity in the expression of individual venom components is maintained in organoid cultures. Harvested venom peptides reflect crude venom composition and display biological activity. This study extends organoid technology to reptilian tissues and describes an experimentally tractable model system representing the snake venom gland.
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Affiliation(s)
- Yorick Post
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences (KNAW) and UMC Utrecht, 3584 CT Utrecht, the Netherlands; Oncode Institute, Hubrecht Institute, 3584 CT Utrecht, the Netherlands
| | - Jens Puschhof
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences (KNAW) and UMC Utrecht, 3584 CT Utrecht, the Netherlands; Oncode Institute, Hubrecht Institute, 3584 CT Utrecht, the Netherlands
| | - Joep Beumer
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences (KNAW) and UMC Utrecht, 3584 CT Utrecht, the Netherlands; Oncode Institute, Hubrecht Institute, 3584 CT Utrecht, the Netherlands
| | - Harald M Kerkkamp
- Naturalis Biodiversity Center, 2333 CR Leiden, the Netherlands; Institute of Biology Leiden, Department of Animal Science and Health, 2333 BE Leiden, the Netherlands
| | - Merijn A G de Bakker
- Institute of Biology Leiden, Department of Animal Science and Health, 2333 BE Leiden, the Netherlands
| | - Julien Slagboom
- Division of BioAnalytical Chemistry, Department of Chemistry and Pharmaceutical Sciences, Vrije Universiteit Amsterdam, 1081 LA Amsterdam, the Netherlands
| | - Buys de Barbanson
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences (KNAW) and UMC Utrecht, 3584 CT Utrecht, the Netherlands; Oncode Institute, Hubrecht Institute, 3584 CT Utrecht, the Netherlands
| | - Nienke R Wevers
- Mimetas BV, Organ-on-a-Chip Company, 2333 CH Leiden, the Netherlands; Department of Cell and Chemical Biology, Leiden University Medical Centre, Einthovenweg 20, 2333 ZC Leiden, the Netherlands
| | - Xandor M Spijkers
- Mimetas BV, Organ-on-a-Chip Company, 2333 CH Leiden, the Netherlands; Department of Translational Neuroscience, Utrecht University Medical Center, 3584 CG Utrecht, the Netherlands
| | - Thomas Olivier
- Mimetas BV, Organ-on-a-Chip Company, 2333 CH Leiden, the Netherlands
| | - Taline D Kazandjian
- Centre for Snakebite Research & Interventions, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool L3 5QA, UK
| | - Stuart Ainsworth
- Centre for Snakebite Research & Interventions, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool L3 5QA, UK
| | - Carmen Lopez Iglesias
- The Maastricht Multimodal Molecular Imaging Institute, Maastricht University, 6229 ER Maastricht, the Netherlands
| | - Willine J van de Wetering
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences (KNAW) and UMC Utrecht, 3584 CT Utrecht, the Netherlands; The Maastricht Multimodal Molecular Imaging Institute, Maastricht University, 6229 ER Maastricht, the Netherlands
| | - Maria C Heinz
- Oncode Institute, Hubrecht Institute, 3584 CT Utrecht, the Netherlands; Molecular Cancer Research, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht University, 3584 CX Utrecht, the Netherlands
| | - Ravian L van Ineveld
- Oncode Institute, Hubrecht Institute, 3584 CT Utrecht, the Netherlands; The Princess Maxima Center for Pediatric Oncology, 3584 CS Utrecht, the Netherlands
| | - Regina G D M van Kleef
- Neurotoxicology Research Group, Division of Toxicology, Institute for Risk Assessment Sciences (IRAS), Utrecht University, 3584 CL Utrecht, the Netherlands
| | - Harry Begthel
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences (KNAW) and UMC Utrecht, 3584 CT Utrecht, the Netherlands; Oncode Institute, Hubrecht Institute, 3584 CT Utrecht, the Netherlands
| | - Jeroen Korving
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences (KNAW) and UMC Utrecht, 3584 CT Utrecht, the Netherlands; Oncode Institute, Hubrecht Institute, 3584 CT Utrecht, the Netherlands
| | - Yotam E Bar-Ephraim
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences (KNAW) and UMC Utrecht, 3584 CT Utrecht, the Netherlands; Oncode Institute, Hubrecht Institute, 3584 CT Utrecht, the Netherlands
| | | | - Anne C Rios
- Oncode Institute, Hubrecht Institute, 3584 CT Utrecht, the Netherlands; The Princess Maxima Center for Pediatric Oncology, 3584 CS Utrecht, the Netherlands
| | - Remco H S Westerink
- Neurotoxicology Research Group, Division of Toxicology, Institute for Risk Assessment Sciences (IRAS), Utrecht University, 3584 CL Utrecht, the Netherlands
| | - Hugo J G Snippert
- Oncode Institute, Hubrecht Institute, 3584 CT Utrecht, the Netherlands; Molecular Cancer Research, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht University, 3584 CX Utrecht, the Netherlands
| | - Alexander van Oudenaarden
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences (KNAW) and UMC Utrecht, 3584 CT Utrecht, the Netherlands; Oncode Institute, Hubrecht Institute, 3584 CT Utrecht, the Netherlands
| | - Peter J Peters
- The Maastricht Multimodal Molecular Imaging Institute, Maastricht University, 6229 ER Maastricht, the Netherlands
| | - Freek J Vonk
- Naturalis Biodiversity Center, 2333 CR Leiden, the Netherlands
| | - Jeroen Kool
- Division of BioAnalytical Chemistry, Department of Chemistry and Pharmaceutical Sciences, Vrije Universiteit Amsterdam, 1081 LA Amsterdam, the Netherlands; Division of BioAnalytical Chemistry, Department of Chemistry and Pharmaceutical Sciences, Amsterdam Institute for Molecules Medicines and Systems, Vrije Universiteit Amsterdam, 1081 HV Amsterdam, the Netherlands
| | - Michael K Richardson
- Institute of Biology Leiden, Department of Animal Science and Health, 2333 BE Leiden, the Netherlands
| | - Nicholas R Casewell
- Centre for Snakebite Research & Interventions, Department of Tropical Disease Biology, Liverpool School of Tropical Medicine, Liverpool L3 5QA, UK
| | - Hans Clevers
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences (KNAW) and UMC Utrecht, 3584 CT Utrecht, the Netherlands; Oncode Institute, Hubrecht Institute, 3584 CT Utrecht, the Netherlands; The Princess Maxima Center for Pediatric Oncology, 3584 CS Utrecht, the Netherlands.
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9
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Hall LM, Hellmer CB, Koehler CC, Ichinose T. Bipolar Cell Type-Specific Expression and Conductance of Alpha-7 Nicotinic Acetylcholine Receptors in the Mouse Retina. Invest Ophthalmol Vis Sci 2019; 60:1353-1361. [PMID: 30934054 PMCID: PMC6738513 DOI: 10.1167/iovs.18-25753] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Purpose Motion detection is performed by a unique neural network in the mouse retina. Starburst amacrine cells (SACs), which release acetylcholine and gamma-aminobutyric acid (GABA) into the network, are key neurons in the motion detection pathway. Although GABA contributions to the network have been extensively studied, the role of acetylcholine is minimally understood. Acetylcholine receptors are present in a subset of bipolar, amacrine, and ganglion cells. We focused on α7-nicotinic acetylcholine receptor (α7-nAChR) expression in bipolar cells, and investigated which types of bipolar cells possess α7-nAChRs. Methods Retinal slice sections were prepared from C57BL/6J and Gus8.4-GFP mice. Specific expression of α7-nAChRs in bipolar cells was examined using α-bungarotoxin (αBgTx)-conjugated Alexa dyes co-labeled with specific bipolar cell markers. Whole-cell recordings were conducted from bipolar cells in retinal slice sections. A selective α7-nAChR agonist, PNU282987, was applied by a puff and responses were recorded. Results αBgTx fluorescence was observed primarily in bipolar cell somas. We found that α7-nAChRs were expressed by the majority of type 1, 2, 4, and 7 bipolar cells. Whole-cell recordings revealed that type 2 and 7 bipolar cells depolarized by PNU application. In contrast, α7-nAChRs were not detected in most of type 3, 5, 6, and rod bipolar cells. Conclusions We found that α7-nAChRs are present in bipolar cells in a type-specific manner. Because these bipolar cells provide synaptic inputs to SACs and direction selective ganglion cells, α7-nAChRs may play a role in direction selectivity by modulating these bipolar cells' outputs.
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Affiliation(s)
- Leo M Hall
- Department of Ophthalmology, Visual and Anatomical Sciences, Wayne State University School of Medicine, Detroit, Michigan, United States
| | - Chase B Hellmer
- Department of Ophthalmology, Visual and Anatomical Sciences, Wayne State University School of Medicine, Detroit, Michigan, United States
| | - Christina C Koehler
- Department of Ophthalmology, Visual and Anatomical Sciences, Wayne State University School of Medicine, Detroit, Michigan, United States
| | - Tomomi Ichinose
- Department of Ophthalmology, Visual and Anatomical Sciences, Wayne State University School of Medicine, Detroit, Michigan, United States
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Utkin YN. Last decade update for three-finger toxins: Newly emerging structures and biological activities. World J Biol Chem 2019; 10:17-27. [PMID: 30622682 PMCID: PMC6314878 DOI: 10.4331/wjbc.v10.i1.17] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 11/20/2018] [Accepted: 12/05/2018] [Indexed: 02/05/2023] Open
Abstract
Three-finger toxins (TFTs) comprise one of largest families of snake venom toxins. While they are principal to and the most toxic components of the venoms of the Elapidae snake family, their presence has also been detected in the venoms of snakes from other families. The first TFT, α-bungarotoxin, was discovered almost 50 years ago and has since been used widely as a specific marker of the α7 and muscle-type nicotinic acetylcholine receptors. To date, the number of TFT amino acid sequences deposited in the UniProt Knowledgebase free-access database is more than 700, and new members are being added constantly. Although structural variations among the TFTs are not numerous, several new structures have been discovered recently; these include the disulfide-bound dimers of TFTs and toxins with nonstandard pairing of disulfide bonds. New types of biological activities have also been demonstrated for the well-known TFTs, and research on this topic has become a hot topic of TFT studies. The classic TFTs α-bungarotoxin and α-cobratoxin, for example, have now been shown to inhibit ionotropic receptors of γ-aminobutyric acid, and some muscarinic toxins have been shown to interact with adrenoceptors. New, unexpected activities have been demonstrated for some TFTs as well, such as toxin interaction with interleukin or insulin receptors and even TFT-activated motility of sperm. This minireview provides a summarization of the data that has emerged in the last decade on the TFTs and their activities.
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Affiliation(s)
- Yuri N Utkin
- Laboratory of Molecular Toxinology, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Moscow 117997, Russia
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11
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Mulcahy MJ, Paulo JA, Hawrot E. Proteomic Investigation of Murine Neuronal α7-Nicotinic Acetylcholine Receptor Interacting Proteins. J Proteome Res 2018; 17:3959-3975. [PMID: 30285449 DOI: 10.1021/acs.jproteome.8b00618] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The α7-nicotinic acetylcholine receptor (α7-nAChR) is a ligand-gated ion channel that is expressed widely in vertebrates and is the principal high-affinity α-bungarotoxin (α-bgtx) binding protein in the mammalian CNS. α7-nAChRs associate with proteins that can modulate its properties. The α7-nAChR interactome is the summation of proteins interacting or associating with α7-nAChRs in a protein complex. To identify an α7-nAChR interactome in neural tissue, we isolated α-bgtx-affinity protein complexes from wild-type and α7-nAChR knockout (α7 KO) mouse whole brain tissue homogenates using α-bgtx-affinity beads. Affinity precipitated proteins were trypsinized and analyzed with an Orbitrap Fusion mass spectrometer. Proteins isolated with the α7-nAChR specific ligand, α-bgtx, were determined to be α7-nAChR associated proteins. The α7-nAChR subunit and 120 additional proteins were identified. Additionally, 369 proteins were identified as binding to α-bgtx in the absence of α7-nAChR expression, thereby identifying nonspecific proteins for α7-nAChR investigations using α-bgtx enrichment. These results expand on our previous investigations of α7-nAChR interacting proteins using α-bgtx-affinity bead isolation by controlling for differences between α7-nAChR and α-bgtx-specific proteins, developing an improved protein isolation methodology, and incorporating the latest technology in mass spectrometry. The α7-nAChR interactome identified in this study includes proteins associated with the expression, localization, function, or modulation of α7-nAChRs, and it provides a foundation for future studies to elucidate how these interactions contribute to human disease.
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Affiliation(s)
- Matthew J Mulcahy
- Division of Biology and Biological Engineering , California Institute of Technology , 1200 East California Boulevard , Pasadena , California 91125-2900 , United States.,Department of Molecular Pharmacology, Physiology and Biotechnology , Brown University , Providence , Rhode Island 02912 , United States
| | - Joao A Paulo
- Department of Cell Biology , Harvard Medical School , 240 Longwood Avenue , Boston , Massachusetts 02115 , United States
| | - Edward Hawrot
- Department of Molecular Pharmacology, Physiology and Biotechnology , Brown University , Providence , Rhode Island 02912 , United States
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12
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Garg BK, Loring RH. Evaluating Commercially Available Antibodies for Rat α7 Nicotinic Acetylcholine Receptors. J Histochem Cytochem 2017; 65:499-512. [PMID: 28763248 DOI: 10.1369/0022155417725304] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Alpha7 nicotinic acetylcholine receptors (α7 nAChRs) are important drug targets in neurological disorders and inflammation, making their detection and localization by validated antibodies highly desirable. However, tests in knockout animals raised questions about specificity of antibodies to mouse α7 nAChRs. To date, methods for validating antibodies for rat or human α7 nAChR have not been reported. We developed a gel-shift assay for western blots using GH4C1 cells expressing either native rat receptors or α7 nAChR-green fluorescent protein (GFP) chimeras to evaluate seven commercially available α7 nAChR antibodies. Blots with anti-GFP antibody detected GFP or α7 nAChR-GFP expressed in GH4C1 cells, and 125I-α-bungarotoxin binding and RNA analysis demonstrated α7 nAChR expression. Validated samples were used to evaluate α7 nAChR antibodies by western blot and immunofluorescence studies. These methods confirmed that two of seven α7 nAChR antibodies identify gel-shifts for α7 nAChR/nAChR-GFP but only one antibody demonstrated low background and significant immunofluorescence differences between wild-type and α7 nAChR expressing GH4C1 cells. However, that polyclonal antibody displayed lot-to-lot variability. Our findings suggest that careful validation methods are required for all α7 nAChR receptor species and antibody lots and that the gel-shift assay may allow for relatively rapid antibody screening.
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Affiliation(s)
- Brijesh K Garg
- Department of Pharmaceutical Science, Northeastern University, Boston, Massachusetts (BKG, RHL)
| | - Ralph H Loring
- Department of Pharmaceutical Science, Northeastern University, Boston, Massachusetts (BKG, RHL)
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13
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Dutertre S, Nicke A, Tsetlin VI. Nicotinic acetylcholine receptor inhibitors derived from snake and snail venoms. Neuropharmacology 2017. [PMID: 28623170 DOI: 10.1016/j.neuropharm.2017.06.011] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The nicotinic acetylcholine receptor (nAChR) represents the prototype of ligand-gated ion channels. It is vital for neuromuscular transmission and an important regulator of neurotransmission. A variety of toxic compounds derived from diverse species target this receptor and have been of elemental importance in basic and applied research. They enabled milestone discoveries in pharmacology and biochemistry ranging from the original formulation of the receptor concept, the first isolation and structural analysis of a receptor protein (the nAChR) to the identification, localization, and differentiation of its diverse subtypes and their validation as a target for therapeutic intervention. Among the venom-derived compounds, α-neurotoxins and α-conotoxins provide the largest families and still represent indispensable pharmacological tools. Application of modified α-neurotoxins provided substantial structural and functional details of the nAChR long before high resolution structures were available. α-bungarotoxin represents not only a standard pharmacological tool and label in nAChR research but also for unrelated proteins tagged with a minimal α-bungarotoxin binding motif. A major advantage of α-conotoxins is their smaller size, as well as superior selectivity for diverse nAChR subtypes that allows their development into ligands with optimized pharmacological and chemical properties and potentially novel drugs. In the following, these two groups of nAChR antagonists will be described focusing on their respective roles in the structural and functional characterization of nAChRs and their development into research tools. In addition, we provide a comparative overview of the diverse α-conotoxin selectivities that can serve as a practical guide for both structure activity studies and subtype classification. This article is part of the Special Issue entitled 'Venom-derived Peptides as Pharmacological Tools.'
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Affiliation(s)
- Sébastien Dutertre
- Institut des Biomolécules Max Mousseron, UMR 5247, Université Montpellier - CNRS, Place Eugène Bataillon, 34095 Montpellier Cedex 5, France
| | - Annette Nicke
- Walther Straub Institute for Pharmacology and Toxicology, Ludwig-Maximilians-Universität, Nußbaumstr. 26, 80336 Munich, Germany.
| | - Victor I Tsetlin
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya str.16/10, Moscow 117999, Russian Federation
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14
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High-Affinity α-Conotoxin PnIA Analogs Designed on the Basis of the Protein Surface Topography Method. Sci Rep 2016; 6:36848. [PMID: 27841338 PMCID: PMC5107951 DOI: 10.1038/srep36848] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Accepted: 10/21/2016] [Indexed: 11/08/2022] Open
Abstract
Despite some success for small molecules, elucidating structure-function relationships for biologically active peptides - the ligands for various targets in the organism - remains a great challenge and calls for the development of novel approaches. Some of us recently proposed the Protein Surface Topography (PST) approach, which benefits from a simplified representation of biomolecules' surface as projection maps, which enables the exposure of the structure-function dependencies. Here, we use PST to uncover the "activity pattern" in α-conotoxins - neuroactive peptides that effectively target nicotinic acetylcholine receptors (nAChRs). PST was applied in order to design several variants of the α-conotoxin PnIA, which were synthesized and thoroughly studied. Among the best was PnIA[R9, L10], which exhibits nanomolar affinity for the α7 nAChR, selectivity and a slow wash-out from this target. Importantly, these mutations could hardly be delineated by "standard" structure-based drug design. The proposed combination of PST with a set of experiments proved very efficient for the rational construction of new bioactive molecules.
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15
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Wei J, Graziane NM, Gu Z, Yan Z. DISC1 Protein Regulates γ-Aminobutyric Acid, Type A (GABAA) Receptor Trafficking and Inhibitory Synaptic Transmission in Cortical Neurons. J Biol Chem 2015; 290:27680-7. [PMID: 26424793 DOI: 10.1074/jbc.m115.656173] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Indexed: 12/12/2022] Open
Abstract
Association studies have suggested that Disrupted-in-Schizophrenia 1 (DISC1) confers a genetic risk at the level of endophenotypes that underlies many major mental disorders. Despite the progress in understanding the significance of DISC1 at neural development, the mechanisms underlying DISC1 regulation of synaptic functions remain elusive. Because alterations in the cortical GABA system have been strongly linked to the pathophysiology of schizophrenia, one potential target of DISC1 that is critically involved in the regulation of cognition and emotion is the GABAA receptor (GABAAR). We found that cellular knockdown of DISC1 significantly reduced GABAAR-mediated synaptic and whole-cell current, whereas overexpression of wild-type DISC1, but not the C-terminal-truncated DISC1 (a schizophrenia-related mutant), significantly increased GABAAR currents in pyramidal neurons of the prefrontal cortex. These effects were accompanied by DISC1-induced changes in surface GABAAR expression. Moreover, the regulation of GABAARs by DISC1 knockdown or overexpression depends on the microtubule motor protein kinesin 1 (KIF5). Our results suggest that DISC1 exerts an important effect on GABAergic inhibitory transmission by regulating KIF5/microtubule-based GABAAR trafficking in the cortex. The knowledge gained from this study would shed light on how DISC1 and the GABA system are linked mechanistically and how their interactions are critical for maintaining a normal mental state.
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Affiliation(s)
- Jing Wei
- From the Department of Physiology and Biophysics, School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, New York 14214 and the Veterans Affairs Western New York Healthcare System, Buffalo, New York 14215
| | - Nicholas M Graziane
- From the Department of Physiology and Biophysics, School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, New York 14214 and
| | - Zhenglin Gu
- From the Department of Physiology and Biophysics, School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, New York 14214 and
| | - Zhen Yan
- From the Department of Physiology and Biophysics, School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, New York 14214 and the Veterans Affairs Western New York Healthcare System, Buffalo, New York 14215
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16
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Kudryavtsev DS, Shelukhina IV, Son LV, Ojomoko LO, Kryukova EV, Lyukmanova EN, Zhmak MN, Dolgikh DA, Ivanov IA, Kasheverov IE, Starkov VG, Ramerstorfer J, Sieghart W, Tsetlin VI, Utkin YN. Neurotoxins from snake venoms and α-conotoxin ImI inhibit functionally active ionotropic γ-aminobutyric acid (GABA) receptors. J Biol Chem 2015. [PMID: 26221036 DOI: 10.1074/jbc.m115.648824] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Ionotropic receptors of γ-aminobutyric acid (GABAAR) regulate neuronal inhibition and are targeted by benzodiazepines and general anesthetics. We show that a fluorescent derivative of α-cobratoxin (α-Ctx), belonging to the family of three-finger toxins from snake venoms, specifically stained the α1β3γ2 receptor; and at 10 μm α-Ctx completely blocked GABA-induced currents in this receptor expressed in Xenopus oocytes (IC50 = 236 nm) and less potently inhibited α1β2γ2 ≈ α2β2γ2 > α5β2γ2 > α2β3γ2 and α1β3δ GABAARs. The α1β3γ2 receptor was also inhibited by some other three-finger toxins, long α-neurotoxin Ls III and nonconventional toxin WTX. α-Conotoxin ImI displayed inhibitory activity as well. Electrophysiology experiments showed mixed competitive and noncompetitive α-Ctx action. Fluorescent α-Ctx, however, could be displaced by muscimol indicating that most of the α-Ctx-binding sites overlap with the orthosteric sites at the β/α subunit interface. Modeling and molecular dynamic studies indicated that α-Ctx or α-bungarotoxin seem to interact with GABAAR in a way similar to their interaction with the acetylcholine-binding protein or the ligand-binding domain of nicotinic receptors. This was supported by mutagenesis studies and experiments with α-conotoxin ImI and a chimeric Naja oxiana α-neurotoxin indicating that the major role in α-Ctx binding to GABAAR is played by the tip of its central loop II accommodating under loop C of the receptors.
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Affiliation(s)
- Denis S Kudryavtsev
- From the Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 16/10 Miklukho-Maklaya Street, Moscow 117997, Russia
| | - Irina V Shelukhina
- From the Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 16/10 Miklukho-Maklaya Street, Moscow 117997, Russia
| | - Lina V Son
- the Moscow Institute of Physics and Technology, Institutsky Per. 9, Dolgoprudny, Moscow Region 141700, Russia
| | - Lucy O Ojomoko
- From the Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 16/10 Miklukho-Maklaya Street, Moscow 117997, Russia
| | - Elena V Kryukova
- From the Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 16/10 Miklukho-Maklaya Street, Moscow 117997, Russia
| | - Ekaterina N Lyukmanova
- From the Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 16/10 Miklukho-Maklaya Street, Moscow 117997, Russia, the Lomonosov Moscow State University, Moscow 119991, Russia, and
| | - Maxim N Zhmak
- From the Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 16/10 Miklukho-Maklaya Street, Moscow 117997, Russia, the Syneuro OOO, ul. Miklukho-Maklaya 16/10, Moscow 117997, Russia
| | - Dmitry A Dolgikh
- From the Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 16/10 Miklukho-Maklaya Street, Moscow 117997, Russia, the Lomonosov Moscow State University, Moscow 119991, Russia, and
| | - Igor A Ivanov
- From the Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 16/10 Miklukho-Maklaya Street, Moscow 117997, Russia
| | - Igor E Kasheverov
- From the Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 16/10 Miklukho-Maklaya Street, Moscow 117997, Russia
| | - Vladislav G Starkov
- From the Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 16/10 Miklukho-Maklaya Street, Moscow 117997, Russia
| | - Joachim Ramerstorfer
- the Department of Molecular Neurosciences, Center for Brain Research, Medical University Vienna, A-1090 Vienna, Austria
| | - Werner Sieghart
- the Department of Molecular Neurosciences, Center for Brain Research, Medical University Vienna, A-1090 Vienna, Austria
| | - Victor I Tsetlin
- From the Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 16/10 Miklukho-Maklaya Street, Moscow 117997, Russia
| | - Yuri N Utkin
- From the Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, 16/10 Miklukho-Maklaya Street, Moscow 117997, Russia,
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17
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Natural compounds interacting with nicotinic acetylcholine receptors: from low-molecular weight ones to peptides and proteins. Toxins (Basel) 2015; 7:1683-701. [PMID: 26008231 PMCID: PMC4448168 DOI: 10.3390/toxins7051683] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2015] [Accepted: 05/07/2015] [Indexed: 12/16/2022] Open
Abstract
Nicotinic acetylcholine receptors (nAChRs) fulfill a variety of functions making identification and analysis of nAChR subtypes a challenging task. Traditional instruments for nAChR research are d-tubocurarine, snake venom protein α-bungarotoxin (α-Bgt), and α-conotoxins, neurotoxic peptides from Conus snails. Various new compounds of different structural classes also interacting with nAChRs have been recently identified. Among the low-molecular weight compounds are alkaloids pibocin, varacin and makaluvamines C and G. 6-Bromohypaphorine from the mollusk Hermissenda crassicornis does not bind to Torpedo nAChR but behaves as an agonist on human α7 nAChR. To get more selective α-conotoxins, computer modeling of their complexes with acetylcholine-binding proteins and distinct nAChRs was used. Several novel three-finger neurotoxins targeting nAChRs were described and α-Bgt inhibition of GABA-A receptors was discovered. Information on the mechanisms of nAChR interactions with the three-finger proteins of the Ly6 family was found. Snake venom phospholipases A2 were recently found to inhibit different nAChR subtypes. Blocking of nAChRs in Lymnaea stagnalis neurons was shown for venom C-type lectin-like proteins, appearing to be the largest molecules capable to interact with the receptor. A huge nAChR molecule sensible to conformational rearrangements accommodates diverse binding sites recognizable by structurally very different compounds.
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18
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MmTX1 and MmTX2 from coral snake venom potently modulate GABAA receptor activity. Proc Natl Acad Sci U S A 2015; 112:E891-900. [PMID: 25675485 DOI: 10.1073/pnas.1415488112] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
GABAA receptors shape synaptic transmission by modulating Cl(-) conductance across the cell membrane. Remarkably, animal toxins that specifically target GABAA receptors have not been identified. Here, we report the discovery of micrurotoxin1 (MmTX1) and MmTX2, two toxins present in Costa Rican coral snake venom that tightly bind to GABAA receptors at subnanomolar concentrations. Studies with recombinant and synthetic toxin variants on hippocampal neurons and cells expressing common receptor compositions suggest that MmTX1 and MmTX2 allosterically increase GABAA receptor susceptibility to agonist, thereby potentiating receptor opening as well as desensitization, possibly by interacting with the α(+)/β(-) interface. Moreover, hippocampal neuron excitability measurements reveal toxin-induced transitory network inhibition, followed by an increase in spontaneous activity. In concert, toxin injections into mouse brain result in reduced basal activity between intense seizures. Altogether, we characterized two animal toxins that enhance GABAA receptor sensitivity to agonist, thereby establishing a previously unidentified class of tools to study this receptor family.
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Hannan S, Mortensen M, Smart TG. Snake neurotoxin α-bungarotoxin is an antagonist at native GABA(A) receptors. Neuropharmacology 2015; 93:28-40. [PMID: 25634239 PMCID: PMC4398322 DOI: 10.1016/j.neuropharm.2015.01.001] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Revised: 12/08/2014] [Accepted: 01/07/2015] [Indexed: 12/25/2022]
Abstract
The snake neurotoxin α-bungarotoxin (α-Bgtx) is a competitive antagonist at nicotinic acetylcholine receptors (nAChRs) and is widely used to study their function and cell-surface expression. Increasingly, α-Bgtx is also used as an imaging tool for fluorophore-labelling studies, and given the structural conservation within the pentameric ligand-gated ion channel family, we assessed whether α-Bgtx could bind to recombinant and native γ-aminobutyric type-A receptors (GABAARs). Applying fluorophore-linked α-Bgtx to recombinant αxβ1/2γ2 GABAARs expressed in HEK-293 cells enabled clear cell-surface labelling of α2β1/2γ2 contrasting with the weaker staining of α1/4β1/2γ2, and no labelling for α3/5/6β1/2γ2. The labelling of α2β2γ2 was abolished by bicuculline, a competitive antagonist at GABAARs, and by d-tubocurarine (d-Tc), which acts in a similar manner at nAChRs and GABAARs. Labelling by α-Bgtx was also reduced by GABA, suggesting that the GABA binding site at the receptor β–α subunit interface forms part of the α-Bgtx binding site. Using whole-cell recording, high concentrations of α-Bgtx (20 μM) inhibited GABA-activated currents at all αxβ2γ2 receptors examined, but at lower concentrations (5 μM), α-Bgtx was selective for α2β2γ2. Using α-Bgtx, at low concentrations, permitted the selective inhibition of α2 subunit-containing GABAARs in hippocampal dentate gyrus granule cells, reducing synaptic current amplitudes without affecting the GABA-mediated tonic current. In conclusion, α-Bgtx can act as an inhibitor at recombinant and native GABAARs and may be used as a selective tool to inhibit phasic but not tonic currents in the hippocampus. Recombinant GABAA receptors are inhibited by α-bungarotoxin The β–α subunit interface of GABAA receptors forms the α-bungarotoxin binding site. α-bungarotoxin can selectively inhibit α2 subunit-containing GABAA receptors (α2β2γ2). α-bungarotoxin inhibits GABA synaptic currents in the hippocampus. GABA-mediated tonic currents are unaffected by α-bungarotoxin
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Affiliation(s)
- Saad Hannan
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Martin Mortensen
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London WC1E 6BT, United Kingdom
| | - Trevor G Smart
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London WC1E 6BT, United Kingdom.
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Three-finger snake neurotoxins and Ly6 proteins targeting nicotinic acetylcholine receptors: pharmacological tools and endogenous modulators. Trends Pharmacol Sci 2014; 36:109-23. [PMID: 25528970 DOI: 10.1016/j.tips.2014.11.003] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Revised: 11/04/2014] [Accepted: 11/10/2014] [Indexed: 02/07/2023]
Abstract
Snake venom neurotoxins and lymphocyte antigen 6 (Ly6) proteins, most of the latter being membrane tethered by a glycosylphosphatidylinositol (GPI) anchor, have a variety of biological activities, but their three-finger (3F) folding combines them in one Ly6/neurotoxin family. Subsets of two groups, represented by α-neurotoxins and Lynx1, respectively, interact with nicotinic acetylcholine receptors (nAChR) and, hence, are of therapeutic interest for the treatment of neurodegenerative diseases, pain, and cancer. Information on the mechanisms of action and 3D structure of the binding sites, which is required for drug design, is available from the 3D structure of α-neurotoxin complexes with nAChR models. Here, I compare the structural and functional features of α-neurotoxins versus Lynx1 and its homologs to get a clearer picture of Lynx1-nAChR interactions that is necessary for fundamental science and practical applications.
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Dionisio L, Bergé I, Bravo M, Esandi MDC, Bouzat C. Neurotransmitter GABA Activates Muscle but Not α7 Nicotinic Receptors. Mol Pharmacol 2014; 87:391-400. [DOI: 10.1124/mol.114.095539] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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22
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Joshi S, Keith KJ, Ilyas A, Kapur J. GABAA receptor membrane insertion rates are specified by their subunit composition. Mol Cell Neurosci 2013; 56:201-11. [PMID: 23714576 DOI: 10.1016/j.mcn.2013.05.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2013] [Revised: 04/03/2013] [Accepted: 05/19/2013] [Indexed: 02/07/2023] Open
Abstract
γ Amino-butyric acid type-A receptors (GABARs) containing γ2 or δ subunits form separate pools of receptors in vivo, with distinct localization and function. We determined the rate of surface membrane insertion of native and recombinant γ2 and δ subunit-containing GABARs (γ2-GABARs and δ-GABARs). Insertion of the α-bungarotoxin binding site (BBS) tagged γ2 subunit (t-γ2)-containing GABARs in the surface membrane of HEK293 cells occurred within minutes and reached a peak by 30 min. In contrast, insertion of the BBS-tagged δ subunit (t-δ)-containing receptors required longer incubation and peaked in 120 min. Insertion of the t-γ2 subunit-containing receptors was not influenced by assembling α1 or α4 subunits. In contrast, insertion of the α4β3t-δ subunit-containing receptors was faster than those containing α1β3t-δ subunits. The rate of insertion of native GABARs in the surface membrane of cultured hippocampal neurons, determined by an antibody saturation assay, was similar to that of the recombinant receptors expressed in HEK293 cells. Insertion of the γ2-GABARs was rapid and new γ2-GABARs were detected on the surface membrane of cell soma and dendrites within minutes. In contrast, insertion of the δ-GABARs was slow and newly inserted receptors were initially present only in the surface membrane of cell soma and later also appeared over the dendrites. Thus the rate of insertion of GABARs was dependent on their subunit composition.
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Affiliation(s)
- Suchitra Joshi
- Department of Neurology, University of Virginia, Charlottesville, VA 22908, United States
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Pohanka M. Alpha7 nicotinic acetylcholine receptor is a target in pharmacology and toxicology. Int J Mol Sci 2012; 13:2219-2238. [PMID: 22408449 PMCID: PMC3292018 DOI: 10.3390/ijms13022219] [Citation(s) in RCA: 110] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2012] [Revised: 01/26/2012] [Accepted: 02/14/2012] [Indexed: 01/18/2023] Open
Abstract
Alpha7 nicotinic acetylcholine receptor (α7 nAChR) is an important part of the cholinergic nerve system in the brain. Moreover, it is associated with a cholinergic anti-inflammatory pathway in the termination of the parasympathetic nervous system. Antagonists of α7 nAChR are a wide group represented by conotoxin and bungarotoxin. Even Alzheimer's disease drug memantine acting as an antagonist in its side pathway belongs in this group. Agonists of α7 nAChR are suitable for treatment of multiple cognitive dysfunctions such as Alzheimer's disease or schizophrenia. Inflammation or even sepsis can be ameliorated by the agonistic acting compounds. Preparations RG3487, SEN34625/WYE-103914, SEN12333, ABT-107, Clozapine, GTS-21, CNI-1493, and AR-R17779 are representative examples of the novel compounds with affinity toward the α7 nAChR. Pharmacological, toxicological, and medicinal significance of α7 nAChR are discussed throughout this paper.
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Affiliation(s)
- Miroslav Pohanka
- Faculty of Military Health Sciences, University of Defence, Trebesska 1575, 50001 Hradec Kralove, Czech Republic; E-Mail: ; Tel.: +420-973253091; Fax: +420-973253091
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Traumatic Brain Injury Elicits Similar Alterations in α7 Nicotinic Receptor Density in Two Different Experimental Models. Neuromolecular Med 2010; 13:44-53. [DOI: 10.1007/s12017-010-8136-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2010] [Accepted: 08/20/2010] [Indexed: 10/19/2022]
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In vitro binding characteristics of [3H]AZ11637326, a novel alpha7-selective neuronal nicotinic receptor agonist radioligand. Eur J Pharmacol 2010; 645:63-9. [PMID: 20674564 DOI: 10.1016/j.ejphar.2010.07.035] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2010] [Revised: 06/09/2010] [Accepted: 07/15/2010] [Indexed: 11/23/2022]
Abstract
AZ11637326 (5'-(2-fluoro[3,4,5(-3)H3]phenyl)-spiro[1-azabicyclo [2.2.2]octane-3,2'(3'H)-furo[2,3-b]pyridine) is a potent partial agonist at the human alpha7 neuronal nicotinic receptor with sub-nanomolar affinity for the human and rat alpha7 [(125)I]alpha-bungarotoxin binding sites. In a search for novel agonist radioligands and imaging ligands for the alpha7 nicotinic receptor, [(3)H]AZ11637326 was synthesized and its in vitro membrane binding properties were characterized. [(3)H]AZ11637326 bound to halpha7-HEK membranes with high specificity (>95%), high affinity (230 pM) and a B(max) of 460 fmol/mg. The rank order of affinity of nicotinic standards determined with [(3)H]AZ11637326 strongly correlated with those determined using the classical alpha7 antagonist [(125)I]alpha-bungarotoxin, indicating that [(3)H]AZ11637326 bound to halpha7-HEK membranes with an alpha7 nicotinic-like pharmacology. The K(i) values for the standards were on average 2.3-fold lower affinity than determined using the prototypical alpha7 nicotinic antagonist [(125)I]alpha-bungarotoxin. Because [(3)H]AZ11637326 specific binding is rapid and reversible, the K(i) values determined using this ligand are more accurate estimates of affinity than those determined using the kinetically sluggish [(125)I]alpha-bungarotoxin. [(3)H]AZ11637326 also bound to a high affinity (510 pM), nicotine-sensitive site on rat hippocampal membranes with an average B(max) of 55 fmol/mg. With rat hippocampal membranes, the nicotine-sensitive fraction of total binding was sub-optimal for a radioligand (~50%), yet the potencies and rank order of the K(i) values for standards were consistent with an alpha7 nicotinic pharmacology. Overall, these studies indicate that [(3)H]AZ11637326 is a useful new in vitro probe of the alpha7 nicotinic receptor agonist site and support its potential utility for in vivo receptor occupancy studies.
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Hone AJ, Whiteaker P, Mohn JL, Jacob MH, McIntosh JM. Alexa Fluor 546-ArIB[V11L;V16A] is a potent ligand for selectively labeling alpha 7 nicotinic acetylcholine receptors. J Neurochem 2010; 114:994-1006. [PMID: 20492354 DOI: 10.1111/j.1471-4159.2010.06819.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The alpha7* (*denotes the possible presence of additional subunits) nicotinic acetylcholine receptor (nAChR) subtype is widely expressed in the vertebrate nervous system and implicated in neuropsychiatric disorders that compromise thought and cognition. In this report, we demonstrate that the recently developed fluorescent ligand Cy3-ArIB[V11L;V16A] labels alpha7 nAChRs in cultured hippocampal neurons. However, photobleaching of this ligand during long image acquisition times prompted us to develop a new derivative. In photostability studies, this new ligand, Alexa Fluor 546-ArIB[V11L;V16A], was significantly more resistant to bleaching than the Cy3 derivative. The classic alpha7 ligand alpha-bungarotoxin binds to alpha1* and alpha9* nAChRs. In contrast, Alexa Fluor 546-ArIB[V11L;V16A] potently (IC(50) 1.8 nM) and selectively blocked alpha7 nAChRs but not alpha1* or alpha9* nAChRs expressed in Xenopus oocytes. Selectivity was further confirmed by competition binding studies of native nAChRs in rat brain membranes. The fluorescence properties of Alexa Fluor 546-ArIB[V11L;V16A] were assessed using human embryonic kidney-293 cells stably transfected with nAChRs; labeling was observed on cells expressing alpha7 but not cells expressing alpha3beta2, alpha3beta4, or alpha4beta2 nAChRs. Further imaging studies demonstrate that Alexa Fluor 546-ArIB[V11L;V16A] labels hippocampal neurons from wild-type mice but not from nAChR alpha7 subunit-null mice. Thus, Alexa Fluor 546-ArIB[V11L;V16A] represents a potent and selective ligand for imaging alpha7 nAChRs.
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Affiliation(s)
- Arik J Hone
- Interdepartmental Program in Neuroscience, University of Utah, Salt Lake City, Utah 84112, USA
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27
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Localisation of pre- and postsynaptic cholinergic markers in the human brain. Behav Brain Res 2010; 221:341-55. [PMID: 20170687 DOI: 10.1016/j.bbr.2010.02.025] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2010] [Accepted: 02/10/2010] [Indexed: 12/20/2022]
Abstract
The cholinergic neurotransmission in the central nervous system plays an important role in modulating cognitive processes such as learning, memory, arousal and sleep as well as in modulating locomotor activity. Dysfunction of the central cholinergic system is involved in numerous neuropsychiatric diseases. This review will provide a synopsis on the regional localisation of cholinergic and cholinoceptive structures within the adult human brain. On the cholinergic site data based on the distribution of choline acetyltransferase-immunoreactive structures are in the focus, complemented by data from acetylcholinesterase and vesicular acetylcholine transporter studies. On the cholinoceptive site, the distribution and localisation of receptors that transduce the acetylcholine message, i.e. the muscarinic and the nicotinic acetylcholine receptors is summarized. In addition to these data obtained on post mortem brain an overview of markers which allow for the in vivo monitoring of the cholinergic system in the brain is given. The detailed knowledge on the distribution and localisation of cholinergic markers in human brain will provide further information on the cholinergic circuits of neurotransmission - a prerequisite for the interpretation of in vivo imaging data and the development of selective diagnostic and therapeutic compounds.
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Tsetlin V, Utkin Y, Kasheverov I. Polypeptide and peptide toxins, magnifying lenses for binding sites in nicotinic acetylcholine receptors. Biochem Pharmacol 2009; 78:720-31. [DOI: 10.1016/j.bcp.2009.05.032] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2009] [Revised: 05/20/2009] [Accepted: 05/21/2009] [Indexed: 10/20/2022]
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Bracamontes JR, Steinbach JH. Steroid interaction with a single potentiating site is sufficient to modulate GABA-A receptor function. Mol Pharmacol 2009; 75:973-81. [PMID: 19176850 DOI: 10.1124/mol.108.053629] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Neuroactive steroids are efficacious potentiators of GABA-A receptors. Recent work has identified a site in the alpha1 subunit of the GABA-A receptor, that is essential for potentiation by steroids. However, each receptor contains two copies of the alpha1 subunit. We generated concatemers of subunits so that the alpha1 subunits could be mutated separately and examined the consequences of mutations that remove potentiation by most neurosteroids (alpha1 Q241L, alpha1 Q241W). Concatemers were expressed in Xenopus laevis oocytes, and activation by GABA, potentiation by neurosteroids, and the agonist activity of piperidine-4-sulfonic acid (P4S) were determined. When the alpha1 Q241L mutation is present in alpha1 subunits the EC(50) for activation by GABA is shifted to higher concentration and potentiation by neurosteroids is diminished. When the alpha1 Q241W mutation is expressed, the EC(50) for GABA is shifted to lower concentration, the relative efficacy of P4S is increased, and potentiation by neurosteroids is diminished. Mutation of only one alpha1 subunit does not produce the full effect of mutating both sites. Overall, the data demonstrate that at a macroscopic level, the presence of a single wild-type steroid-binding site is sufficient to mediate responses to steroid, but both must be mutated to completely remove the effects of steroids. Differences between the two sites seem to be relatively subtle.
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Affiliation(s)
- John R Bracamontes
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO 63110, USA
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Bracamontes JR, Steinbach JH. Multiple modes for conferring surface expression of homomeric beta1 GABAA receptors. J Biol Chem 2008; 283:26128-36. [PMID: 18650446 DOI: 10.1074/jbc.m801292200] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The gamma-aminobutyric acid type A (GABA(A)) receptor assembles from individual subunits to form ligand-gated ion channels. Human (h) beta3 subunits assemble to form homomeric surface receptors in somatic cells, but hbeta1 subunits do not. We have identified three distinct sets of amino acid residues in the N-terminal extracellular domain of the hbeta1 subunit, which when mutated to the homologous residue in hbeta3 allow expression as a functional homomeric receptor. The three sets likely result in three modes of assembly. Mode 1 expression results from a single amino acid change at residue hbeta1 Asp-37. Mode 2 expression results from mutations of residues between positions 44 and 73 together with residues between positions 169 and 173. Finally, mode 3 results from the mutations A45V and K196R. Examination of homology-based structural models indicates that many of the residues are unlikely to be involved in physical inter-subunit interactions, suggesting that a major alteration is stabilization of an assembly competent form of the subunit. These mutations do not, however, have a major effect on the surface expression of heteromeric receptors which include the alpha1 subunit.
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Affiliation(s)
- John R Bracamontes
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
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31
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McCann CM, Lichtman JW. In vivo imaging of presynaptic terminals and postsynaptic sites in the mouse submandibular ganglion. Dev Neurobiol 2008; 68:760-70. [PMID: 18383540 DOI: 10.1002/dneu.20621] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Much of what is currently known about the behavior of synapses in vivo has been learned at the mammalian neuromuscular junction, because it is large and accessible and also its postsynaptic acetylcholine receptors (AChRs) are readily labeled with a specific, high-affinity probe, alpha-bungarotoxin (BTX). Neuron-neuron synapses have thus far been much less accessible. We therefore developed techniques for imaging interneuronal synapses in an accessible ganglion in the peripheral nervous system. In the submandibular ganglion, individual preganglionic axons establish large numbers of axo-somatic synapses with postganglionic neurons. To visualize these sites of synaptic contact, presynaptic axons were imaged by using transgenic mice that express fluorescent protein in preganglionic neurons. The postsynaptic sites were visualized by labeling the acetylcholine receptor (AChR) alpha7 subunit with fluorescently tagged BTX. We developed in vivo methods to acquire three-dimensional image stacks of the axons and postsynaptic sites and then follow them over time. The submandibular ganglion is an ideal site to study the formation, elimination, and maintenance of synaptic connections between neurons in vivo.
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Affiliation(s)
- Corey M McCann
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts 02138, USA
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Shin EJ, Chae JS, Jung ME, Bing G, Ko KH, Kim WK, Wie MB, Cheon MA, Nah SY, Kim HC. Repeated intracerebroventricular infusion of nicotine prevents kainate-induced neurotoxicity by activating the α7 nicotinic acetylcholine receptor. Epilepsy Res 2007; 73:292-8. [PMID: 17174071 DOI: 10.1016/j.eplepsyres.2006.11.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2006] [Revised: 11/10/2006] [Accepted: 11/16/2006] [Indexed: 10/23/2022]
Abstract
We examined whether (-)-nicotine infusion can affect kainic acid (KA)-induced neurotoxicity in rats. Although treatment with a single nicotine infusion (0.5 or 1.0 microg/side, i.c.v.) failed to attenuate KA-induced neurotoxicity, repeated nicotine infusions (1.0 microg/side/day for 10 days) attenuated the seizures, the severe loss of cells in hippocampal regions CA1 and CA3, the increase in activator protein (AP)-1 DNA binding activity, and mortality after KA administration. alpha-Bungarotoxin and mecamylamine blocked the neuroprotective effects of nicotine. These results suggest that repeated nicotine treatment provides alpha7 nicotinic acetylcholine receptor-mediated neuroprotection against KA toxicity.
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Affiliation(s)
- Eun-Joo Shin
- Neuropsychopharmacology and Toxicology Program, College of Pharmacy, Kangwon National University, Chunchon 200-701, South Korea
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Moser N, Mechawar N, Jones I, Gochberg-Sarver A, Orr-Urtreger A, Plomann M, Salas R, Molles B, Marubio L, Roth U, Maskos U, Winzer-Serhan U, Bourgeois JP, Le Sourd AM, De Biasi M, Schröder H, Lindstrom J, Maelicke A, Changeux JP, Wevers A. Evaluating the suitability of nicotinic acetylcholine receptor antibodies for standard immunodetection procedures. J Neurochem 2007; 102:479-92. [PMID: 17419810 DOI: 10.1111/j.1471-4159.2007.04498.x] [Citation(s) in RCA: 166] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Nicotinic acetylcholine receptors play important roles in numerous cognitive processes as well as in several debilitating central nervous system (CNS) disorders. In order to fully elucidate the diverse roles of nicotinic acetylcholine receptors in CNS function and dysfunction, a detailed knowledge of their cellular and subcellular localizations is essential. To date, methods to precisely localize nicotinic acetylcholine receptors in the CNS have predominantly relied on the use of anti-receptor subunit antibodies. Although data obtained by immunohistology and immunoblotting are generally in accordance with ligand binding studies, some discrepancies remain, in particular with electrophysiological findings. In this context, nicotinic acetylcholine receptor subunit-deficient mice should be ideal tools for testing the specificity of subunit-directed antibodies. Here, we used standard protocols for immunohistochemistry and western blotting to examine the antibodies raised against the alpha3-, alpha4-, alpha7-, beta2-, and beta4-nicotinic acetylcholine receptor subunits on brain tissues of the respective knock-out mice. Unexpectedly, for each of the antibodies tested, immunoreactivity was the same in wild-type and knock-out mice. These data imply that, under commonly used conditions, these antibodies are not suited for immunolocalization. Thus, particular caution should be exerted with regards to the experimental approach used to visualize nicotinic acetylcholine receptors in the brain.
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Affiliation(s)
- N Moser
- Department II of Anatomy, Neuroanatomy, University of Cologne, Cologne, Germany
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35
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Charest JL, García AJ, King WP. Myoblast alignment and differentiation on cell culture substrates with microscale topography and model chemistries. Biomaterials 2007; 28:2202-10. [PMID: 17267031 DOI: 10.1016/j.biomaterials.2007.01.020] [Citation(s) in RCA: 182] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2006] [Accepted: 01/04/2007] [Indexed: 12/14/2022]
Abstract
This paper analyzes the alignment and differentiation of myoblast cells adherent to surfaces having model chemistries and microtopographical patterns. The patterns strongly influenced cellular alignment but did not modulate expression of differentiation marker proteins in either primary or C2C12 myoblasts. Topographic patterns consisted of embossed ridges and grooves or arrays of holes, with feature sizes ranging from 5-75 microm. The topographic surfaces were prepared with a uniform self-assembled monolayer that presented CH3 molecules for fibronectin adsorption. The myoblast cell models were cultured in differentiation conditions on the substrates. For both cell models, cells aligned to grooves, with groove width modulating orientation, and preferentially orientated parallel to rows of holes. None of the patterns significantly modulated cell density or differentiation as examined through sarcomeric myosin and acetylcholine receptor expression. The results indicate that for the specific configuration examined, microscale topography modulates myoblast alignment, but does not have significant impact on cell density or differentiation.
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Affiliation(s)
- Joseph L Charest
- The George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30329-0405, USA
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Bogdanov Y, Michels G, Armstrong-Gold C, Haydon PG, Lindstrom J, Pangalos M, Moss SJ. Synaptic GABAA receptors are directly recruited from their extrasynaptic counterparts. EMBO J 2006; 25:4381-9. [PMID: 16946701 PMCID: PMC1570424 DOI: 10.1038/sj.emboj.7601309] [Citation(s) in RCA: 137] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2006] [Accepted: 08/03/2006] [Indexed: 11/08/2022] Open
Abstract
GABAA receptors mediate the majority of fast synaptic inhibition in the brain. The accumulation of these ligand-gated ion channels at synaptic sites is a prerequisite for neuronal inhibition, but the molecular mechanisms underlying this phenomenon remain obscure. To further understand these processes, we have examined the cellular origins of synaptic GABAA receptors. To do so, we have created fluorescent GABAA receptors that are capable of binding -bungarotoxin (Bgt), facilitating the visualization of receptor endocytosis, exocytosis and delivery to synaptic sites. Imaging with Bgt in hippocampal neurons revealed that GABAA receptor endocytosis occurred exclusively at extrasynaptic sites, consistent with the preferential colocalization of extrasynaptic receptors with the AP2 adaptin. Receptor insertion into the plasma membrane was also predominantly extrasynaptic, and pulse-chase analysis revealed that these newly inserted receptors were then able to access directly synaptic sites. Therefore, our results demonstrate that synaptic GABAA receptors are directly recruited from their extrasynaptic counterparts. Moreover, they illustrate a dynamic mechanism for neurons to modulate GABAA receptor number at inhibitory synapses by controlling the stability of extrasynaptic receptors.
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Affiliation(s)
- Yury Bogdanov
- Department of Neuroscience, University of Pennsylvania, Philadelphia, PA, USA
- Department of Pharmacology, University College, London, UK
| | - Guido Michels
- Department of Neuroscience, University of Pennsylvania, Philadelphia, PA, USA
- Department of Pharmacology, University College, London, UK
- Department of Internal Medicine III, University of Cologne, Cologne, Germany
| | | | - Philip G Haydon
- Department of Neuroscience, University of Pennsylvania, Philadelphia, PA, USA
| | - Jon Lindstrom
- Department of Neuroscience, University of Pennsylvania, Philadelphia, PA, USA
| | | | - Stephen J Moss
- Department of Neuroscience, University of Pennsylvania, Philadelphia, PA, USA
- Department of Pharmacology, University College, London, UK
- Department of Neuroscience, University of Pennsylvania, 145 Johnson Pavilion, Hamilton Walk, Philadelphia, PA 19104, USA. Tel.: +1 215 898 1998; Fax: +1 215 898 1347; E-mail:
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Massey KA, Zago WM, Berg DK. BDNF up-regulates alpha7 nicotinic acetylcholine receptor levels on subpopulations of hippocampal interneurons. Mol Cell Neurosci 2006; 33:381-8. [PMID: 17029981 PMCID: PMC1826088 DOI: 10.1016/j.mcn.2006.08.011] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2006] [Revised: 08/04/2006] [Accepted: 08/30/2006] [Indexed: 12/18/2022] Open
Abstract
In the hippocampus, brain-derived neurotrophic factor (BDNF) regulates a number of synaptic components. Among these are nicotinic acetylcholine receptors containing alpha7 subunits (alpha7-nAChRs), which are interesting because of their relative abundance in the hippocampus and their high relative calcium permeability. We show here that BDNF elevates surface and intracellular pools of alpha7-nAChRs on cultured hippocampal neurons and that glutamatergic activity is both necessary and sufficient for the effect. Blocking transmission through NMDA receptors with APV blocked the BDNF effect; increasing spontaneous excitatory activity with the GABA(A) receptor antagonist bicuculline replicated the BDNF effect. BDNF antibodies blocked the BDNF-mediated increase but not the bicuculline one, consistent with enhanced glutamatergic activity acting downstream from BDNF. Increased alpha7-nAChR clusters were most prominent on interneuron subtypes known to directly innervate excitatory neurons. The results suggest that BDNF, acting through glutamatergic transmission, can modulate hippocampal output in part by controlling alpha7-nAChR levels.
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Affiliation(s)
- Kerri A Massey
- Neurobiology Section, Division of Biological Sciences, 0357, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0357, USA.
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