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Brill-Weil SG, Kramer PF, Yanez A, Clever FH, Zhang R, Khaliq ZM. Presynaptic GABA A receptors control integration of nicotinic input onto dopaminergic axons in the striatum. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.25.600616. [PMID: 39372741 PMCID: PMC11451734 DOI: 10.1101/2024.06.25.600616] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/08/2024]
Abstract
Axons of dopaminergic neurons express gamma-aminobutyric acid type-A receptors (GABAARs) and nicotinic acetylcholine receptors (nAChRs) which are both independently positioned to shape striatal dopamine release. Using electrophysiology and calcium imaging, we investigated how interactions between GABAARs and nAChRs influence dopaminergic axon excitability. Direct axonal recordings showed that benzodiazepine application suppresses subthreshold axonal input from cholinergic interneurons (CINs). In imaging experiments, we used the first temporal derivative of presynaptic calcium signals to distinguish between direct- and nAChR-evoked activity in dopaminergic axons. We found that GABAAR antagonism with gabazine selectively enhanced nAChR-evoked axonal signals. Acetylcholine release was unchanged in gabazine suggesting that GABAARs located on dopaminergic axons, but not CINs, mediated this enhancement. Unexpectedly, we found that a widely used GABAAR antagonist, picrotoxin, inhibits axonal nAChRs and should be used cautiously for striatal circuit analysis. Overall, we demonstrate that GABAARs on dopaminergic axons regulate integration of nicotinic input to shape presynaptic excitability.
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Affiliation(s)
- Samuel G. Brill-Weil
- Cellular Neurophysiology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, 20892, USA
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD, 20815, USA
| | - Paul F. Kramer
- Cellular Neurophysiology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, 20892, USA
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD, 20815, USA
| | - Anthony Yanez
- Cellular Neurophysiology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, 20892, USA
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD, 20815, USA
| | - Faye H. Clever
- Cellular Neurophysiology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, 20892, USA
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD, 20815, USA
| | - Renshu Zhang
- Cellular Neurophysiology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, 20892, USA
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD, 20815, USA
| | - Zayd M. Khaliq
- Cellular Neurophysiology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, 20892, USA
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD, 20815, USA
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Williams BM, Steed ND, Woolley JT, Moedl AA, Nelson CA, Jones GC, Burris MD, Arias HR, Kim OH, Jang EY, Hone AJ, McIntosh JM, Yorgason JT, Steffensen SC. Catharanthine Modulates Mesolimbic Dopamine Transmission and Nicotine Psychomotor Effects via Inhibition of α6-Nicotinic Receptors and Dopamine Transporters. ACS Chem Neurosci 2024; 15:1738-1754. [PMID: 38613458 DOI: 10.1021/acschemneuro.3c00478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/15/2024] Open
Abstract
Iboga alkaloids, also known as coronaridine congeners, have shown promise in the treatment of alcohol and opioid use disorders. The objective of this study was to evaluate the effects of catharanthine and 18-methoxycoronaridine (18-MC) on dopamine (DA) transmission and cholinergic interneurons in the mesolimbic DA system, nicotine-induced locomotor activity, and nicotine-taking behavior. Utilizing ex vivo fast-scan cyclic voltammetry (FSCV) in the nucleus accumbens core of male mice, we found that catharanthine or 18-MC differentially inhibited evoked DA release. Catharanthine inhibition of evoked DA release was significantly reduced by both α4 and α6 nicotinic acetylcholine receptors (nAChRs) antagonists. Additionally, catharanthine substantially increased DA release more than vehicle during high-frequency stimulation, although less potently than an α4 nAChR antagonist, which confirms previous work with nAChR antagonists. Interestingly, while catharanthine slowed DA reuptake measured via FSCV ex vivo, it also increased extracellular DA in striatal dialysate from anesthetized mice in vivo in a dose-dependent manner. Superfusion of catharanthine or 18-MC inhibited the firing rate of striatal cholinergic interneurons in a concentration dependent manner, which are known to potently modulate presynaptic DA release. Catharanthine or 18-MC suppressed acetylcholine currents in oocytes expressing recombinant rat α6/α3β2β3 or α6/α3β4 nAChRs. In behavioral experiments using male Sprague-Dawley rats, systemic administration of catharanthine or 18-MC blocked nicotine enhancement of locomotor activity. Importantly, catharanthine attenuated nicotine self-administration in a dose-dependent manner while having no effect on food reinforcement. Lastly, administration of catharanthine and nicotine together greatly increased head twitch responses, indicating a potential synergistic hallucinogenic effect. These findings demonstrate that catharanthine and 18-MC have similar, but not identical effects on striatal DA dynamics, striatal cholinergic interneuron activity and nicotine psychomotor effects.
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Affiliation(s)
- Benjamin M Williams
- Department of Psychology/Neuroscience, Brigham Young University, Provo, Utah 84602, United States
| | - Nathan D Steed
- Department of Psychology/Neuroscience, Brigham Young University, Provo, Utah 84602, United States
| | - Joel T Woolley
- Department of Psychology/Neuroscience, Brigham Young University, Provo, Utah 84602, United States
| | - Aubrey A Moedl
- Department of Psychology/Neuroscience, Brigham Young University, Provo, Utah 84602, United States
| | - Christina A Nelson
- Department of Psychology/Neuroscience, Brigham Young University, Provo, Utah 84602, United States
| | - Gavin C Jones
- Department of Psychology/Neuroscience, Brigham Young University, Provo, Utah 84602, United States
| | - Matthew D Burris
- Department of Psychology/Neuroscience, Brigham Young University, Provo, Utah 84602, United States
| | - Hugo R Arias
- Department of Pharmacology and Physiology, Oklahoma State University College of Osteopathic Medicine, Tahlequah, Oklahoma 74464, United States
| | - Oc-Hee Kim
- Department of Advanced Toxicology Research, Korea Institute of Toxicology, 141 Gajeong-ro, Yuseong-gu, Daejeon 34114, Korea
| | - Eun Young Jang
- Department of Advanced Toxicology Research, Korea Institute of Toxicology, 141 Gajeong-ro, Yuseong-gu, Daejeon 34114, Korea
| | - Arik J Hone
- George E. Wahlen Veterans Affairs Medical Center, and Departments of Psychiatry and Biology, University of Utah, Salt Lake City, Utah 84112, United States
| | - J Michael McIntosh
- George E. Wahlen Veterans Affairs Medical Center, and Departments of Psychiatry and Biology, University of Utah, Salt Lake City, Utah 84112, United States
| | - Jordan T Yorgason
- Department of Psychology/Neuroscience, Brigham Young University, Provo, Utah 84602, United States
| | - Scott C Steffensen
- Department of Psychology/Neuroscience, Brigham Young University, Provo, Utah 84602, United States
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Carreño D, Facundo A, Nguyen MTT, Lotfipour S. Dopamine and Norepinephrine Tissue Levels in the Developing Limbic Brain Are Impacted by the Human CHRNA6 3'-UTR Single-Nucleotide Polymorphism (rs2304297) in Rats. Int J Mol Sci 2024; 25:3676. [PMID: 38612487 PMCID: PMC11011259 DOI: 10.3390/ijms25073676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2024] [Revised: 03/16/2024] [Accepted: 03/19/2024] [Indexed: 04/14/2024] Open
Abstract
We previously demonstrated that a genetic single-nucleotide polymorphism (SNP, rs2304297) in the 3' untranslated region (UTR) of the human CHRNA6 gene has sex- and genotype-dependent effects on nicotine-induced locomotion, anxiety, and nicotine + cue-induced reinstatement in adolescent rats. This study aims to investigate how the CHRNA6 3'-UTR SNP influences dopaminergic and noradrenergic tissue levels in brain reward regions during baseline and after the reinstatement of drug-seeking behavior. Naïve adolescent and adult rats, along with those undergoing nicotine + cue reinstatement and carrying the CHRNA6 3'-UTR SNP, were assessed for dopamine (DA), norepinephrine (NE), and metabolites in reward pathway regions. The results reveal age-, sex-, and genotype-dependent baseline DA, NE, and DA turnover levels. Post-reinstatement, male α6GG rats show suppressed DA levels in the Nucleus Accumbens (NAc) Shell compared to the baseline, while nicotine+ cue-induced reinstatement behavior correlates with neurotransmitter levels in specific brain regions. This study emphasizes the role of CHRNA6 3'-UTR SNP in the developmental maturation of the dopaminergic and noradrenergic system in the adolescent rat brain, with tissue levels acting as predictors of nicotine + cue-induced reinstatement.
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Affiliation(s)
- Diana Carreño
- Department of Emergency Medicine, University of California, Irvine, CA 92697, USA
| | - Antonella Facundo
- Department of Emergency Medicine, University of California, Irvine, CA 92697, USA
| | - My Trang Thi Nguyen
- Department of Pharmaceutical Sciences, University of California, Irvine, CA 92697, USA
| | - Shahrdad Lotfipour
- Department of Emergency Medicine, University of California, Irvine, CA 92697, USA
- Department of Pharmaceutical Sciences, University of California, Irvine, CA 92697, USA
- Department of Pathology and Laboratory Medicine, University of California, Irvine, CA 92617, USA
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Souf YM, Lokaj G, Kuruva V, Saed Y, Raviglione D, Brik A, Nicke A, Inguimbert N, Dutertre S. Synthesis and Biological Activity of Novel α-Conotoxins Derived from Endemic Polynesian Cone Snails. Mar Drugs 2023; 21:356. [PMID: 37367681 DOI: 10.3390/md21060356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 06/06/2023] [Accepted: 06/07/2023] [Indexed: 06/28/2023] Open
Abstract
α-Conotoxins are well-known probes for the characterization of the various subtypes of nicotinic acetylcholine receptors (nAChRs). Identifying new α-conotoxins with different pharmacological profiles can provide further insights into the physiological or pathological roles of the numerous nAChR isoforms found at the neuromuscular junction, the central and peripheral nervous systems, and other cells such as immune cells. This study focuses on the synthesis and characterization of two novel α-conotoxins obtained from two species endemic to the Marquesas Islands, namely Conus gauguini and Conus adamsonii. Both species prey on fish, and their venom is considered a rich source of bioactive peptides that can target a wide range of pharmacological receptors in vertebrates. Here, we demonstrate the versatile use of a one-pot disulfide bond synthesis to achieve the α-conotoxin fold [Cys 1-3; 2-4] for GaIA and AdIA, using the 2-nitrobenzyl (NBzl) protecting group of cysteines for effective regioselective oxidation. The potency and selectivity of GaIA and AdIA against rat nicotinic acetylcholine receptors were investigated electrophysiologically and revealed potent inhibitory activities. GaIA was most active at the muscle nAChR (IC50 = 38 nM), whereas AdIA was most potent at the neuronal α6/3 β2β3 subtype (IC50 = 177 nM). Overall, this study contributes to a better understanding of the structure-activity relationships of α-conotoxins, which may help in the design of more selective tools.
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Affiliation(s)
- Yazid Mohamed Souf
- CRIOBE, UAR CNRS-EPHE-UPVD 3278, Université de Perpignan Via Domitia, 58 Avenue Paul Alduy, 66860 Perpignan, France
| | - Gonxhe Lokaj
- Faculty of Medicine, Walther Straub Institute of Pharmacology and Toxicology, Ludwig Maximilian University of Munich, Nußbaumstraße 26, 80336 Munich, Germany
| | - Veeresh Kuruva
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Haifa 3200008, Israel
| | - Yakop Saed
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Haifa 3200008, Israel
| | - Delphine Raviglione
- CRIOBE, UAR CNRS-EPHE-UPVD 3278, Université de Perpignan Via Domitia, 58 Avenue Paul Alduy, 66860 Perpignan, France
| | - Ashraf Brik
- Schulich Faculty of Chemistry, Technion-Israel Institute of Technology, Haifa 3200008, Israel
| | - Annette Nicke
- Faculty of Medicine, Walther Straub Institute of Pharmacology and Toxicology, Ludwig Maximilian University of Munich, Nußbaumstraße 26, 80336 Munich, Germany
| | - Nicolas Inguimbert
- CRIOBE, UAR CNRS-EPHE-UPVD 3278, Université de Perpignan Via Domitia, 58 Avenue Paul Alduy, 66860 Perpignan, France
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5
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Wadsworth HA, Anderson EQ, Williams BM, Ronström JW, Moen JK, Lee AM, McIntosh JM, Wu J, Yorgason JT, Steffensen SC. Role of α6-Nicotinic Receptors in Alcohol-Induced GABAergic Synaptic Transmission and Plasticity to Cholinergic Interneurons in the Nucleus Accumbens. Mol Neurobiol 2023; 60:3113-3129. [PMID: 36802012 PMCID: PMC10690621 DOI: 10.1007/s12035-023-03263-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Accepted: 02/03/2023] [Indexed: 02/21/2023]
Abstract
The prevailing view is that enhancement of dopamine (DA) transmission in the mesolimbic system, consisting of DA neurons in the ventral tegmental area (VTA) that project to the nucleus accumbens (NAc), underlies the reward properties of ethanol (EtOH) and nicotine (NIC). We have shown previously that EtOH and NIC modulation of DA release in the NAc is mediated by α6-containing nicotinic acetylcholine receptors (α6*-nAChRs), that α6*-nAChRs mediate low-dose EtOH effects on VTA GABA neurons and EtOH preference, and that α6*-nAChRs may be a molecular target for low-dose EtOH. However, the most sensitive target for reward-relevant EtOH modulation of mesolimbic DA transmission and the involvement of α6*-nAChRs in the mesolimbic DA reward system remains to be elucidated. The aim of this study was to evaluate EtOH effects on GABAergic modulation of VTA GABA neurons and VTA GABAergic input to cholinergic interneurons (CINs) in the NAc. Low-dose EtOH enhanced GABAergic input to VTA GABA neurons that was blocked by knockdown of α6*-nAChRs. Knockdown was achieved either by α6-miRNA injected into the VTA of VGAT-Cre/GAD67-GFP mice or by superfusion of the α-conotoxin MII[H9A;L15A] (MII). Superfusion of MII blocked EtOH inhibition of mIPSCs in NAc CINs. Concomitantly, EtOH enhanced CIN firing rate, which was blocked by knockdown of α6*-nAChRs with α6-miRNA injected into the VTA of VGAT-Cre/GAD67-GFP mice. The firing rate of CINs was not enhanced by EtOH in EtOH-dependent mice, and low-frequency stimulation (LFS; 1 Hz, 240 pulses) caused inhibitory long-term depression at this synapse (VTA-NAc CIN-iLTD) which was blocked by knockdown of α6*-nAChR and MII. Ethanol inhibition of CIN-mediated evoked DA release in the NAc was blocked by MII. Taken together, these findings suggest that α6*-nAChRs in the VTA-NAc pathway are sensitive to low-dose EtOH and play a role in plasticity associated with chronic EtOH.
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Affiliation(s)
- Hillary A Wadsworth
- Department of Psychology and Neuroscience, Brigham Young University, 1050 KMBL, Provo, UT, 84602, USA
| | - Elizabeth Q Anderson
- Department of Psychology and Neuroscience, Brigham Young University, 1050 KMBL, Provo, UT, 84602, USA
| | - Benjamin M Williams
- Department of Psychology and Neuroscience, Brigham Young University, 1050 KMBL, Provo, UT, 84602, USA
| | - Joakim W Ronström
- Department of Psychology and Neuroscience, Brigham Young University, 1050 KMBL, Provo, UT, 84602, USA
| | - Janna K Moen
- Department of Pharmacology, Graduate Program in Neuroscience, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Anna M Lee
- Department of Pharmacology, Graduate Program in Neuroscience, University of Minnesota, Minneapolis, MN, 55455, USA
| | - J Michael McIntosh
- School of Biological Sciences and Department of Psychiatry, University of Utah, Salt Lake City, UT, 84108, USA
- George E. Whalen Veterans Affairs Medical Center, Salt Lake City, UT, 84148, USA
| | - Jie Wu
- Brain Function and Disease Laboratory, Shantou University Medical College, Shantou, 515041, Guangdong, China
| | - Jordan T Yorgason
- Department of Psychology and Neuroscience, Brigham Young University, 1050 KMBL, Provo, UT, 84602, USA
| | - Scott C Steffensen
- Department of Psychology and Neuroscience, Brigham Young University, 1050 KMBL, Provo, UT, 84602, USA.
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Tae HS, Adams DJ. Nicotinic acetylcholine receptor subtype expression, function, and pharmacology: Therapeutic potential of α-conotoxins. Pharmacol Res 2023; 191:106747. [PMID: 37001708 DOI: 10.1016/j.phrs.2023.106747] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Revised: 03/22/2023] [Accepted: 03/27/2023] [Indexed: 04/03/2023]
Abstract
The pentameric nicotinic acetylcholine receptors (nAChRs) are typically classed as muscle- or neuronal-type, however, the latter has also been reported in non-neuronal cells. Given their broad distribution, nAChRs mediate numerous physiological and pathological processes including synaptic transmission, presynaptic modulation of transmitter release, neuropathic pain, inflammation, and cancer. There are 17 different nAChR subunits and combinations of these subunits produce subtypes with diverse pharmacological properties. The expression and role of some nAChR subtypes have been extensively deciphered with the aid of knock-out models. Many nAChR subtypes expressed in heterologous systems are selectively targeted by the disulfide-rich α-conotoxins. α-Conotoxins are small peptides isolated from the venom of cone snails, and a number of them have potential pharmaceutical value.
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Zhu X, Wang S, Kaas Q, Yu J, Wu Y, Harvey PJ, Zhangsun D, Craik DJ, Luo S. Discovery, Characterization, and Engineering of LvIC, an α4/4-Conotoxin That Selectively Blocks Rat α6/α3β4 Nicotinic Acetylcholine Receptors. J Med Chem 2023; 66:2020-2031. [PMID: 36682014 DOI: 10.1021/acs.jmedchem.2c01786] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
α6β4 nicotinic acetylcholine receptors (nAChRs) are expressed in the central and peripheral nervous systems, but their functions are not fully understood, largely because of a lack of specific ligands. Here, we characterized a novel α-conotoxin, LvIC, and designed a series of analogues to probe structure-activity relationships at the α6β4 nAChR. The potency and selectivity of these conotoxins were tested using two-electrode voltage-clamp recording on nAChR subtypes expressed in Xenopus laevis oocytes. One of the analogues, [D1G,ΔQ14]LvIC, potently blocked α6/α3β4 nAChRs (α6/α3 is a chimera) with an IC50 of 19 nM, with minimal activity at other nAChR subtypes, including the structurally similar α6/α3β2β3 and α3β4 subtypes. Using NMR, molecular docking, and receptor mutation, structure-activity relationships of [D1G,ΔQ14]LvIC at the α6/α3β4 nAChR were defined. It is a potent and specific antagonist of α6β4 nAChRs that could potentially serve as a novel molecular probe to explore α6β4 nAChR-related neurophysiological and pharmacological functions.
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Affiliation(s)
- Xiaopeng Zhu
- School of Medicine, Guangxi University, Nanning 530004, China
| | - Shuai Wang
- Center for Novel Target and Therapeutic Intervention, Institute of Life Sciences, Chongqing Medical University, Chongqing 400016, China
| | - Quentin Kaas
- Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane 4072, Queensland, Australia
| | - Jinpeng Yu
- School of Medicine, Guangxi University, Nanning 530004, China
| | - Yong Wu
- School of Medicine, Guangxi University, Nanning 530004, China
| | - Peta J Harvey
- Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane 4072, Queensland, Australia
| | - Dongting Zhangsun
- School of Medicine, Guangxi University, Nanning 530004, China.,Key Laboratory of Tropical Biological Resources of Ministry of Education, Hainan University, Haikou 570228, China
| | - David J Craik
- Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane 4072, Queensland, Australia
| | - Sulan Luo
- School of Medicine, Guangxi University, Nanning 530004, China.,Key Laboratory of Tropical Biological Resources of Ministry of Education, Hainan University, Haikou 570228, China
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Maddux JM, Gonzales L, Kregar NP. β2* nicotinic acetylcholine receptor subtypes mediate nicotine-induced enhancement of Pavlovian conditioned responding to an alcohol cue. Front Behav Neurosci 2022; 16:1004368. [PMCID: PMC9596985 DOI: 10.3389/fnbeh.2022.1004368] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Accepted: 09/21/2022] [Indexed: 11/13/2022] Open
Abstract
Nicotine enhances Pavlovian conditioned responses to reward-associated cues. We investigated through which nicotinic acetylcholine receptor (nAChR) subtypes nicotine acts to produce this behavioral effect to an alcohol-associated cue. Male Long-Evans rats with freely available food and water were first accustomed to drinking 15% ethanol in their home cages using an intermittent access, two-bottle choice procedure. Then the rats were given 15 Pavlovian conditioning sessions in which a 15-s audiovisual conditioned stimulus (CS) predicted the delivery of 0.2 ml of ethanol, the unconditioned stimulus (US). Each session contained 12 CS-US trials. A control group received explicitly unpaired presentations of the CS and US. We measured Pavlovian conditioned approach to the site of US delivery during presentations of the CS, accounting for pre-CS baseline activity. Before each conditioning session, rats were injected subcutaneously with nicotine (0.4 mg/kg) or saline (1 ml/kg). During nAChR antagonist test sessions, rats were first injected systemically with the β2*-selective nAChR antagonist dihydro-beta-erythroidine (DHβE; 3 mg/kg) or the α7-selective nAChR antagonist methyllycaconitine (MLA; 6 mg/kg), followed by their assigned nicotine or saline injection before assessing their conditioned response to the alcohol-associated cue. Consistent with previous reports, nicotine enhanced the Pavlovian conditioned response to the alcohol-paired cue. DHβE attenuated this enhancement, whereas MLA did not. These results suggest that nicotine acts via β2*, but not α7, nAChRs to amplify Pavlovian conditioned responding to an alcohol cue. These findings contribute to a growing literature that identifies nAChRs as potential targets for pharmacological treatment of co-morbid alcohol and tobacco use disorders.
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Affiliation(s)
- Jean-Marie Maddux
- Department of Psychology, Lake Forest College, Lake Forest, IL, United States
- Neuroscience Program, Lake Forest College, Lake Forest, IL, United States
- *Correspondence: Jean-Marie Maddux
| | - Leslie Gonzales
- Department of Psychology, Lake Forest College, Lake Forest, IL, United States
- Neuroscience Program, Lake Forest College, Lake Forest, IL, United States
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Kramer PF, Brill-Weil SG, Cummins AC, Zhang R, Camacho-Hernandez GA, Newman AH, Eldridge MAG, Averbeck BB, Khaliq ZM. Synaptic-like axo-axonal transmission from striatal cholinergic interneurons onto dopaminergic fibers. Neuron 2022; 110:2949-2960.e4. [PMID: 35931070 PMCID: PMC9509469 DOI: 10.1016/j.neuron.2022.07.011] [Citation(s) in RCA: 44] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 06/22/2022] [Accepted: 07/12/2022] [Indexed: 12/09/2022]
Abstract
Transmission from striatal cholinergic interneurons (CINs) controls dopamine release through nicotinic acetylcholine receptors (nAChRs) on dopaminergic axons. Anatomical studies suggest that cholinergic terminals signal predominantly through non-synaptic volume transmission. However, the influence of cholinergic transmission on electrical signaling in axons remains unclear. We examined axo-axonal transmission from CINs onto dopaminergic axons using perforated-patch recordings, which revealed rapid spontaneous EPSPs with properties characteristic of fast synapses. Pharmacology showed that axonal EPSPs (axEPSPs) were mediated primarily by high-affinity α6-containing receptors. Remarkably, axEPSPs triggered spontaneous action potentials, suggesting that these axons perform integration to convert synaptic input into spiking, a function associated with somatodendritic compartments. We investigated the cross-species validity of cholinergic axo-axonal transmission by recording dopaminergic axons in macaque putamen and found similar axEPSPs. Thus, we reveal that synaptic-like neurotransmission underlies cholinergic signaling onto dopaminergic axons, supporting the idea that striatal dopamine release can occur independently of somatic firing to provide distinct signaling.
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Affiliation(s)
- Paul F Kramer
- Cellular Neurophysiology Section, National Institute of Neurological Disorders and Stroke Intramural Research Program, National Institutes of Health, Bethesda, MD 20892, USA
| | - Samuel G Brill-Weil
- Cellular Neurophysiology Section, National Institute of Neurological Disorders and Stroke Intramural Research Program, National Institutes of Health, Bethesda, MD 20892, USA
| | - Alex C Cummins
- Laboratory of Neuropsychology, National Institute of Mental Health Intramural Research Program, National Institutes of Health, Bethesda, MD 20892, USA
| | - Renshu Zhang
- Cellular Neurophysiology Section, National Institute of Neurological Disorders and Stroke Intramural Research Program, National Institutes of Health, Bethesda, MD 20892, USA
| | - Gisela A Camacho-Hernandez
- Medicinal Chemistry Section, National Institute on Drug Abuse Intramural Research Program, National Institutes of Health, Baltimore, MD 21224, USA
| | - Amy H Newman
- Medicinal Chemistry Section, National Institute on Drug Abuse Intramural Research Program, National Institutes of Health, Baltimore, MD 21224, USA
| | - Mark A G Eldridge
- Laboratory of Neuropsychology, National Institute of Mental Health Intramural Research Program, National Institutes of Health, Bethesda, MD 20892, USA
| | - Bruno B Averbeck
- Laboratory of Neuropsychology, National Institute of Mental Health Intramural Research Program, National Institutes of Health, Bethesda, MD 20892, USA
| | - Zayd M Khaliq
- Cellular Neurophysiology Section, National Institute of Neurological Disorders and Stroke Intramural Research Program, National Institutes of Health, Bethesda, MD 20892, USA.
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10
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Hone AJ, McIntosh JM. Alkaloid ligands enable function of homomeric human α10 nicotinic acetylcholine receptors. Front Pharmacol 2022; 13:981760. [PMID: 36188578 PMCID: PMC9523446 DOI: 10.3389/fphar.2022.981760] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Accepted: 08/23/2022] [Indexed: 01/29/2023] Open
Abstract
In the nervous system, nicotinic acetylcholine receptors (nAChRs) rapidly transduce a chemical signal into one that is electrical via ligand-gated ion flux through the central channel of the receptor. However, some nAChR subunits are expressed by non-excitable cells where signal transduction apparently occurs through non-ionic mechanisms. One such nAChR subunit, α10, is present in a discreet subset of immune cells and has been implicated in pathologies including cancer, neuropathic pain, and chronic inflammation. Longstanding convention holds that human α10 subunits require co-assembly with α9 subunits for function. Here we assessed whether cholinergic ligands can enable or uncover ionic functions from homomeric α10 nAChRs. Xenopus laevis oocytes expressing human α10 subunits were exposed to a panel of ligands and examined for receptor activation using voltage-clamp electrophysiology. Functional expression of human α10 nAChRs was achieved by exposing the oocytes to the alkaloids strychnine, brucine, or methyllycaconitine. Furthermore, acute exposure to the alkaloid ligands significantly enhanced ionic responses. Acetylcholine-gated currents mediated by α10 nAChRs were potently inhibited by the snake toxins α-bungarotoxin and α-cobratoxin but not by α-conotoxins that target α9 and α9α10 nAChRs. Our findings indicate that human α10 homomers are expressed in oocytes and exposure to certain ligands can enable ionic functions. To our knowledge, this is the first demonstration that human α10 subunits can assemble as functional homomeric nAChRs. These findings have potential implications for receptor regulatory-mechanisms and will enable structural, functional, and further pharmacological characterization of human α10 nAChRs.
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Affiliation(s)
- Arik J. Hone
- School of Biological Sciences, University of Utah, Salt Lake City, UT, United States
- MIRECC, George E. Whalen Veterans Affairs Medical Center, Salt Lake City, UT, United States
| | - J. Michael McIntosh
- School of Biological Sciences, University of Utah, Salt Lake City, UT, United States
- Department of Psychiatry, University of Utah, Salt Lake City, UT, United States
- George E. Whalen Veterans Affairs Medical Center, Salt Lake City, UT, United States
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11
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Zhang Y, Roy DS, Zhu Y, Chen Y, Aida T, Hou Y, Shen C, Lea NE, Schroeder ME, Skaggs KM, Sullivan HA, Fischer KB, Callaway EM, Wickersham IR, Dai J, Li XM, Lu Z, Feng G. Targeting thalamic circuits rescues motor and mood deficits in PD mice. Nature 2022; 607:321-329. [PMID: 35676479 PMCID: PMC9403858 DOI: 10.1038/s41586-022-04806-x] [Citation(s) in RCA: 34] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Accepted: 04/26/2022] [Indexed: 01/03/2023]
Abstract
Although bradykinesia, tremor and rigidity are the hallmark motor defects in patients with Parkinson's disease (PD), patients also experience motor learning impairments and non-motor symptoms such as depression1. The neural circuit basis for these different symptoms of PD are not well understood. Although current treatments are effective for locomotion deficits in PD2,3, therapeutic strategies targeting motor learning deficits and non-motor symptoms are lacking4-6. Here we found that distinct parafascicular (PF) thalamic subpopulations project to caudate putamen (CPu), subthalamic nucleus (STN) and nucleus accumbens (NAc). Whereas PF→CPu and PF→STN circuits are critical for locomotion and motor learning, respectively, inhibition of the PF→NAc circuit induced a depression-like state. Whereas chemogenetically manipulating CPu-projecting PF neurons led to a long-term restoration of locomotion, optogenetic long-term potentiation (LTP) at PF→STN synapses restored motor learning behaviour in an acute mouse model of PD. Furthermore, activation of NAc-projecting PF neurons rescued depression-like phenotypes. Further, we identified nicotinic acetylcholine receptors capable of modulating PF circuits to rescue different PD phenotypes. Thus, targeting PF thalamic circuits may be an effective strategy for treating motor and non-motor deficits in PD.
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Affiliation(s)
- Ying Zhang
- McGovern Institute for Brain Research, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA.
| | - Dheeraj S Roy
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, USA.
| | - Yi Zhu
- Center for Neuroscience and Department of Neurology of Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Yefei Chen
- Shenzhen Key Laboratory for Molecular Biology of Neural Development, The Brain Cognition and Brain Disease Institute, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
- Shenzhen-Hong Kong Institute of Brain Science, Shenzhen, China
| | - Tomomi Aida
- McGovern Institute for Brain Research, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Yuanyuan Hou
- McGovern Institute for Brain Research, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Chenjie Shen
- McGovern Institute for Brain Research, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Nicholas E Lea
- McGovern Institute for Brain Research, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Margaret E Schroeder
- McGovern Institute for Brain Research, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Keith M Skaggs
- McGovern Institute for Brain Research, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Heather A Sullivan
- McGovern Institute for Brain Research, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Kyle B Fischer
- Systems Neurobiology Laboratories, Salk Institute for Biological Studies, La Jolla, CA, USA
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
| | - Edward M Callaway
- Systems Neurobiology Laboratories, Salk Institute for Biological Studies, La Jolla, CA, USA
- Department of Neurosciences, University of California San Diego, La Jolla, CA, USA
| | - Ian R Wickersham
- McGovern Institute for Brain Research, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Ji Dai
- Shenzhen Key Laboratory for Molecular Biology of Neural Development, The Brain Cognition and Brain Disease Institute, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
- Shenzhen-Hong Kong Institute of Brain Science, Shenzhen, China
| | - Xiao-Ming Li
- Center for Neuroscience and Department of Neurology of Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
- NHC and CAMS Key Laboratory of Medical Neurobiology, Center for Brain Science and Brain-Inspired Intelligence, Guangdong-Hong Kong-Macao Greater Bay Area, Zhejiang University, Hangzhou, China
- Joint Institute for Genetics and Genome Medicine between Zhejiang University and University of Toronto, Zhejiang University, Hangzhou, China
| | - Zhonghua Lu
- Shenzhen Key Laboratory for Molecular Biology of Neural Development, The Brain Cognition and Brain Disease Institute, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
- Shenzhen-Hong Kong Institute of Brain Science, Shenzhen, China
| | - Guoping Feng
- McGovern Institute for Brain Research, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, USA.
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, USA.
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12
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Kassner M, Eaton JB, Tang N, Petit JL, Meurice N, Yin HH, Whiteaker P. High-throughput cell-based assays for identifying antagonists of multiple smoking-associated human nicotinic acetylcholine receptor subtypes. SLAS DISCOVERY : ADVANCING LIFE SCIENCES R & D 2022; 27:68-76. [PMID: 35058178 PMCID: PMC8816891 DOI: 10.1016/j.slasd.2021.10.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
There is substantial evidence that in addition to nicotine, other compounds found in tobacco smoke significantly influence smoking behavior. Further, recent years have seen an explosion in the availability of non-combusted products that deliver nicotine, such as e-cigarettes and “home-brew” vaping devices that are essentially unregulated. There are many thousands of compounds in tobacco smoke alone, and new products are constantly introducing new compounds. Uncovering which of these compounds are active, across multiple smoking-relevant subtypes of the nicotinic acetylcholine receptor (nAChR) that influence tobacco/nicotine addiction, requires a high-throughput screening (HTS) approach. Accordingly, we developed a panel of HTS-friendly cell-based assays, all performed in the same cellular background and using the same membrane potential dye readout, to measure the function of the α3β4-, α4β2-, and α6β2-nAChR subtypes. These subtypes have each been prominently and consistently associated with human smoking behavior. We validated our assays by performing pilot screening of an expanded set of the Prestwick FDA-approved drug library. The screens displayed excellent performance parameters, and moderate hit rates (mean of 1.2% across all three assays) were achieved when identifying antagonists (chosen since effects of endogenous antagonists on consumption of nicotine/tobacco products are under-studied). Validation rates using an orthogonal assay (86Rb+ efflux) averaged 73% across the three assays. The resulting panel of assays represents a valuable new platform with which to screen and identify nAChR subtype-selective compounds. This provides a resource for identifying smoking-related compounds in both combusted and non-combusted tobacco products, with potential relevance in the search for additional smoking-cessation therapies.
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Affiliation(s)
- Michelle Kassner
- Cancer and Cell Biology Division, Translational Genomics Research Institute, Phoenix, AZ 85004, United States
| | - J Brek Eaton
- Division of Neurobiology, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, 350 W. Thomas Rd., Phoenix, AZ 85013, United States
| | - Nanyun Tang
- Cancer and Cell Biology Division, Translational Genomics Research Institute, Phoenix, AZ 85004, United States
| | - Joachim L Petit
- Department of Hematology/Oncology, Mayo Clinic, Scottsdale, AZ 85259, United States
| | - Nathalie Meurice
- Department of Hematology/Oncology, Mayo Clinic, Scottsdale, AZ 85259, United States
| | - Hongwei Holly Yin
- Cancer and Cell Biology Division, Translational Genomics Research Institute, Phoenix, AZ 85004, United States.
| | - Paul Whiteaker
- Division of Neurobiology, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, 350 W. Thomas Rd., Phoenix, AZ 85013, United States.
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13
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Ho TNT, Abraham N, Lewis RJ. Rigidity of loop 1 contributes to equipotency of globular and ribbon isomers of α-conotoxin AusIA. Sci Rep 2021; 11:21928. [PMID: 34753970 PMCID: PMC8578332 DOI: 10.1038/s41598-021-01277-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Accepted: 10/19/2021] [Indexed: 11/09/2022] Open
Abstract
α-Conotoxins are small disulfide-rich peptides targeting nicotinic acetylcholine receptors (nAChRs) characterised by a CICII-Xm-CIII-Xn-CIV framework that invariably adopt the native globular conformations which is typically most potent. α-Conotoxins are divided into several structural subgroups based on the number of residues within the two loops braced by the disulfide bonds (m/n), with the 4/7 and 4/3 subgroups dominating. AusIA is a relatively rare α5/5-conotoxin isolated from the venom of Conus australis. Surprisingly, the ribbon isomer displayed equipotency to the wild-type globular AusIA at human α7-containing nAChR. To understand the molecular basis for equipotency, we determined the co-crystal structures of both isomers at Lymnea stagnalis acetylcholine binding protein. The additional residue in the first loop of AusIA was found to be a critical determinant of equipotency, with 11-fold and 86-fold shifts in potency in favour of globular AusIA over ribbon AusIA observed following deletion of Ala4 or Arg5, respectively. This divergence in the potency between globular AusIA and ribbon AusIA was further enhanced upon truncation of the non-conserved Val at the C-termini. Conversely, equipotency could be replicated in LsIA and TxIA [A10L] following insertion of an Ala in the first loop. These findings provide a new understanding of the role the first loop in ribbon and globular α-conotoxins can play in directing α-conotoxin nAChR pharmacology.
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Affiliation(s)
- Thao N T Ho
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, 4067, Australia
| | - Nikita Abraham
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, 4067, Australia
| | - Richard J Lewis
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, 4067, Australia.
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14
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Wu X, Craik DJ, Kaas Q. Interactions of Globular and Ribbon [γ4E]GID with α4β2 Neuronal Nicotinic Acetylcholine Receptor. Mar Drugs 2021; 19:md19090482. [PMID: 34564144 PMCID: PMC8469569 DOI: 10.3390/md19090482] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 08/24/2021] [Accepted: 08/24/2021] [Indexed: 02/05/2023] Open
Abstract
The α4β2 nAChR is implicated in a range of diseases and disorders including nicotine addiction, epilepsy and Parkinson's and Alzheimer's diseases. Designing α4β2 nAChR selective inhibitors could help define the role of the α4β2 nAChR in such disease states. In this study, we aimed to modify globular and ribbon α-conotoxin GID to selectively target the α4β2 nAChR through competitive inhibition of the α4(+)β2(-) or α4(+)α4(-) interfaces. The binding modes of the globular α-conotoxin [γ4E]GID with rat α3β2, α4β2 and α7 nAChRs were deduced using computational methods and were validated using published experimental data. The binding mode of globular [γ4E]GID at α4β2 nAChR can explain the experimental mutagenesis data, suggesting that it could be used to design GID variants. The predicted mutational energy results showed that globular [γ4E]GID is optimal for binding to α4β2 nAChR and its activity could not likely be further improved through amino-acid substitutions. The binding mode of ribbon GID with the (α4)3(β2)2 nAChR was deduced using the information from the cryo-electron structure of (α4)3(β2)2 nAChR and the binding mode of ribbon AuIB. The program FoldX predicted the mutational energies of ribbon [γ4E]GID at the α4(+)α4(-) interface, and several ribbon[γ4E]GID mutants were suggested to have desirable properties to inhibit (α4)3(β2)2 nAChR.
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Affiliation(s)
- Xiaosa Wu
- Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, QLD 4072, Australia;
- National Institutes of Health, Building 35A, Room 3D-953B, 35 Convent Drive, Bethesda, MD 20892-3701, USA
| | - David J. Craik
- Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, QLD 4072, Australia;
- Correspondence: (D.J.C.); (Q.K.)
| | - Quentin Kaas
- Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, QLD 4072, Australia;
- Correspondence: (D.J.C.); (Q.K.)
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15
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Guo M, Yu J, Zhu X, Zhangsun D, Luo S. Characterization of an α 4/7-Conotoxin LvIF from Conus lividus That Selectively Blocks α3β2 Nicotinic Acetylcholine Receptor. Mar Drugs 2021; 19:md19070398. [PMID: 34356823 PMCID: PMC8306566 DOI: 10.3390/md19070398] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 07/12/2021] [Accepted: 07/14/2021] [Indexed: 11/16/2022] Open
Abstract
Nicotinic acetylcholine receptor (nAChR), a member of pentameric ligand-gated ion channel transmembrane protein composed of five subunits, is widely distributed in the central and peripheral nervous system. The nAChRs are associated with various neurological diseases, including schizophrenia, Alzheimer’s disease, Parkinson’s disease, epilepsy and neuralgia. Receptors containing the α3 subunit are associated with analgesia, generating our interest in their role in pharmacological studies. In this study, α-conotoxin (α-CTx) LvIF was identified as a 16 amino acid peptide using a genomic DNA clone of Conus lividus (C. lividus). The mature LvIF with natural structure was synthesized by a two-step oxidation method. The blocking potency of α-CTx lvIF on nAChR was detected by a two-electrode voltage clamp. Our results showed that α-CTx LvIF was highly potent against rα3β2 and rα6/α3β2β3 nAChR subtypes, The half-maximal inhibitory concentration (IC50) values of α-CTx LvIF against rα3β2 and rα6/α3β2β3 nAChRs expressed in Xenopus oocytes were 8.9 nM and 14.4 nM, respectively. Furthermore, α-CTx LvIF exhibited no obvious inhibition on other nAChR subtypes. Meanwhile, we also conducted a competitive binding experiment between α-CTxs MII and LvIF, which showed that α-CTxs LvIF and MII bind with rα3β2 nAChR at the partial overlapping domain. These results indicate that the α-CTx LvIF has high potential as a new candidate tool for the studying of rα3β2 nAChR related neurophysiology and pharmacology.
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Affiliation(s)
- Man Guo
- Key Laboratory of Tropical Biological Resources of Ministry of Education, Key Laboratory for Marine Drugs of Haikou, School of Life and Pharmaceutical Sciences, Hainan University, Haikou 570228, China;
| | - Jinpeng Yu
- Medical School, Guangxi University, Nanning 530004, China; (J.Y.); (X.Z.)
| | - Xiaopeng Zhu
- Medical School, Guangxi University, Nanning 530004, China; (J.Y.); (X.Z.)
| | - Dongting Zhangsun
- Key Laboratory of Tropical Biological Resources of Ministry of Education, Key Laboratory for Marine Drugs of Haikou, School of Life and Pharmaceutical Sciences, Hainan University, Haikou 570228, China;
- Medical School, Guangxi University, Nanning 530004, China; (J.Y.); (X.Z.)
- Correspondence: (D.Z.); (S.L.)
| | - Sulan Luo
- Key Laboratory of Tropical Biological Resources of Ministry of Education, Key Laboratory for Marine Drugs of Haikou, School of Life and Pharmaceutical Sciences, Hainan University, Haikou 570228, China;
- Medical School, Guangxi University, Nanning 530004, China; (J.Y.); (X.Z.)
- Correspondence: (D.Z.); (S.L.)
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16
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Bekbossynova A, Zharylgap A, Filchakova O. Venom-Derived Neurotoxins Targeting Nicotinic Acetylcholine Receptors. Molecules 2021; 26:molecules26113373. [PMID: 34204855 PMCID: PMC8199771 DOI: 10.3390/molecules26113373] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 05/05/2021] [Accepted: 05/07/2021] [Indexed: 01/02/2023] Open
Abstract
Acetylcholine was the first neurotransmitter described. The receptors targeted by acetylcholine are found within organisms spanning different phyla and position themselves as very attractive targets for predation, as well as for defense. Venoms of snakes within the Elapidae family, as well as those of marine snails within the Conus genus, are particularly rich in proteins and peptides that target nicotinic acetylcholine receptors (nAChRs). Such compounds are invaluable tools for research seeking to understand the structure and function of the cholinergic system. Proteins and peptides of venomous origin targeting nAChR demonstrate high affinity and good selectivity. This review aims at providing an overview of the toxins targeting nAChRs found within venoms of different animals, as well as their activities and the structural determinants important for receptor binding.
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17
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Ning H, Huang B, Tae HS, Liu Z, Yu S, Li L, Zhang L, Adams DJ, Guo C, Dai Q. α-Conotoxin Bt1.8 from Conus betulinus selectively inhibits α6/α3β2β3 and α3β2 nicotinic acetylcholine receptor subtypes. J Neurochem 2021; 159:90-100. [PMID: 34008858 DOI: 10.1111/jnc.15434] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2020] [Revised: 04/16/2021] [Accepted: 04/27/2021] [Indexed: 12/01/2022]
Abstract
α-Conotoxins are small disulfide-rich peptides found in the venom of marine cone snails and are potent antagonists of nicotinic acetylcholine receptors (nAChRs). They are valuable pharmacological tools and have potential therapeutic applications for the treatment of chronic pain or neurological diseases and disorders. In the present study, we synthesized and functionally characterized a novel α-conotoxin Bt1.8, which was cloned from Conus betulinus. Bt1.8 selectively inhibited ACh-evoked currents in Xenopus oocytes expressing rat(r) α6/α3β2β3 and rα3β2 nAChRs with an IC50 of 2.1 nM and 9.4 nM, respectively, and similar potency for human (h) α6/α3β2β3 and hα3β2 nAChRs. Additionally, Bt1.8 had higher binding affinity with a slower dissociation rate for the rα6/α3β2β3 subtype compared to rα3β2. The amino acid sequence of Bt1.8 is significantly different from other reported α-conotoxins targeting the two nAChR subtypes. Further Alanine scanning analyses demonstrated that residues Ile9, Leu10, Asn11, Asn12 and Asn14 are critical for its inhibitory activity at the α6/α3β2β3 and α3β2 subtypes. Moreover, the NMR structure of Bt1.8 indicated the presence of a relatively larger hydrophobic zone than other α4/7-conotoxins which may explain its potent inhibition at α6/α3β2β3 nAChRs.
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Affiliation(s)
- Huying Ning
- Beijing Institute of Biotechnology, Beijing, China
| | - Biling Huang
- Department of Chemical Biology, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, China
| | - Han-Shen Tae
- Illawarra Health and Medical Research Institute (IHMRI), University of Wollongong, Wollongong, NSW, Australia
| | - Zhuguo Liu
- Beijing Institute of Biotechnology, Beijing, China
| | - Shuo Yu
- Beijing Institute of Biotechnology, Beijing, China
| | - Liang Li
- Beijing Institute of Biotechnology, Beijing, China
| | | | - David J Adams
- Illawarra Health and Medical Research Institute (IHMRI), University of Wollongong, Wollongong, NSW, Australia
| | - Chenyun Guo
- Department of Chemical Biology, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, China
| | - Qiuyun Dai
- Beijing Institute of Biotechnology, Beijing, China
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18
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Moen JK, DeBaker MC, Myjak JE, Wickman K, Lee AM. Bidirectional sex-dependent regulation of α6 and β3 nicotinic acetylcholine receptors by protein kinase Cε. Addict Biol 2021; 26:e12954. [PMID: 32776643 PMCID: PMC7873155 DOI: 10.1111/adb.12954] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 07/10/2020] [Accepted: 07/19/2020] [Indexed: 11/29/2022]
Abstract
Nicotine and alcohol are the most commonly abused substances worldwide and are frequently coabused. Nicotinic acetylcholine receptors (nAChRs) containing the α6 and β3 subunits are expressed in neural reward circuits and are critical for nicotine and alcohol reward. nAChRs are dynamically regulated by signaling molecules such as protein kinase C epsilon (PKCε), which impact transcription of α6 and β3 subunit mRNA (Chrna6 and Chrnb3, respectively). Previous work found decreased expression of Chrna6 and Chrnb3 transcripts in the ventral midbrain of male PKCε-/- mice, who also consume less nicotine and alcohol compared with wild-type (WT) littermates. Using RT-qPCR, we show that female PKCε-/- mice have higher expression of Chrna6 and Chrnb3 transcripts in the ventral midbrain, which functionally impacts nAChR-dependent behavior as female but not male PKCε-/- mice exhibit locomotor hypersensitivity to low-dose (0.25 mg/kg i.p.) nicotine. Female PKCε-/- mice show no differences in alcohol-induced sedation in the loss-of-righting reflex assay (4.0 g/kg i.p.) compared with WT littermates, whereas male PKCε-/- mice have enhanced sedation compared with WT mice. Female PKCε-/- mice also show reduced immobility time in response to varenicline (1.0 mg/kg i.p.) compared with WT littermates in the tail suspension test, and this effect was absent in male mice. Additionally, we found that female PKCε-/- mice show altered alcohol and nicotine consumption patterns in chronic voluntary two-bottle choice assays. Our data reveal a bidirectional effect of sex in the transcriptional regulation of nicotinic receptors by PKCε, highlighting the importance of studying both sexes in preclinical animal models.
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Affiliation(s)
- Janna K. Moen
- Graduate Program in Neuroscience, University of Minnesota, USA
| | | | - Julia E. Myjak
- Department of Pharmacology, University of Minnesota, USA
| | - Kevin Wickman
- Graduate Program in Neuroscience, University of Minnesota, USA
- Department of Pharmacology, University of Minnesota, USA
| | - Anna M. Lee
- Graduate Program in Neuroscience, University of Minnesota, USA
- Department of Pharmacology, University of Minnesota, USA
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19
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Synthesis, Structural and Pharmacological Characterizations of CIC, a Novel α-Conotoxin with an Extended N-Terminal Tail. Mar Drugs 2021; 19:md19030141. [PMID: 33801301 PMCID: PMC8001506 DOI: 10.3390/md19030141] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 02/15/2021] [Accepted: 02/25/2021] [Indexed: 01/11/2023] Open
Abstract
Cone snails are venomous marine predators that rely on fast-acting venom to subdue their prey and defend against aggressors. The conotoxins produced in the venom gland are small disulfide-rich peptides with high affinity and selectivity for their pharmacological targets. A dominant group comprises α-conotoxins, targeting nicotinic acetylcholine receptors. Here, we report on the synthesis, structure determination and biological activity of a novel α-conotoxin, CIC, found in the predatory venom of the piscivorous species Conus catus and its truncated mutant Δ-CIC. CIC is a 4/7 α-conotoxin with an unusual extended N-terminal tail. High-resolution NMR spectroscopy shows a major influence of the N-terminal tail on the apparent rigidity of the three-dimensional structure of CIC compared to the more flexible Δ-CIC. Surprisingly, this effect on the structure does not alter the biological activity, since both peptides selectively inhibit α3β2 and α6/α3β2β3 nAChRs with almost identical sub- to low micromolar inhibition constants. Our results suggest that the N-terminal part of α-conotoxins can accommodate chemical modifications without affecting their pharmacology.
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20
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Terpinskaya TI, Osipov AV, Kryukova EV, Kudryavtsev DS, Kopylova NV, Yanchanka TL, Palukoshka AF, Gondarenko EA, Zhmak MN, Tsetlin VI, Utkin YN. α-Conotoxins and α-Cobratoxin Promote, while Lipoxygenase and Cyclooxygenase Inhibitors Suppress the Proliferation of Glioma C6 Cells. Mar Drugs 2021; 19:md19020118. [PMID: 33669933 PMCID: PMC7956437 DOI: 10.3390/md19020118] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 02/01/2021] [Accepted: 02/18/2021] [Indexed: 12/11/2022] Open
Abstract
Among the brain tumors, glioma is the most common. In general, different biochemical mechanisms, involving nicotinic acetylcholine receptors (nAChRs) and the arachidonic acid cascade are involved in oncogenesis. Although the engagement of the latter in survival and proliferation of rat C6 glioma has been shown, there are practically no data about the presence and the role of nAChRs in C6 cells. In this work we studied the effects of nAChR antagonists, marine snail α-conotoxins and snake α-cobratoxin, on the survival and proliferation of C6 glioma cells. The effects of the lipoxygenase and cyclooxygenase inhibitors either alone or together with α-conotoxins and α-cobratoxin were studied in parallel. It was found that α-conotoxins and α-cobratoxin promoted the proliferation of C6 glioma cells, while nicotine had practically no effect at concentrations below 1 µL/mL. Nordihydroguaiaretic acid, a nonspecific lipoxygenase inhibitor, and baicalein, a 12-lipoxygenase inhibitor, exerted antiproliferative and cytotoxic effects on C6 cells. nAChR inhibitors weaken this effect after 24 h cultivation but produced no effects at longer times. Quantitative real-time polymerase chain reaction showed that mRNA for α4, α7, β2 and β4 subunits of nAChR were expressed in C6 glioma cells. This is the first indication for involvement of nAChRs in mechanisms of glioma cell proliferation.
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Affiliation(s)
- Tatiana I. Terpinskaya
- Institute of Physiology, National Academy of Sciences of Belarus, ul. Akademicheskaya, 28, 220072 Minsk, Belarus; (T.I.T.); (T.L.Y.); (A.F.P.)
| | - Alexey V. Osipov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, ul. Miklukho-Maklaya 16/10, 117997 Moscow, Russia; (A.V.O.); (E.V.K.); (D.S.K.); (N.V.K.); (E.A.G.); (M.N.Z.); (V.I.T.)
| | - Elena V. Kryukova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, ul. Miklukho-Maklaya 16/10, 117997 Moscow, Russia; (A.V.O.); (E.V.K.); (D.S.K.); (N.V.K.); (E.A.G.); (M.N.Z.); (V.I.T.)
| | - Denis S. Kudryavtsev
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, ul. Miklukho-Maklaya 16/10, 117997 Moscow, Russia; (A.V.O.); (E.V.K.); (D.S.K.); (N.V.K.); (E.A.G.); (M.N.Z.); (V.I.T.)
| | - Nina V. Kopylova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, ul. Miklukho-Maklaya 16/10, 117997 Moscow, Russia; (A.V.O.); (E.V.K.); (D.S.K.); (N.V.K.); (E.A.G.); (M.N.Z.); (V.I.T.)
| | - Tatsiana L. Yanchanka
- Institute of Physiology, National Academy of Sciences of Belarus, ul. Akademicheskaya, 28, 220072 Minsk, Belarus; (T.I.T.); (T.L.Y.); (A.F.P.)
| | - Alena F. Palukoshka
- Institute of Physiology, National Academy of Sciences of Belarus, ul. Akademicheskaya, 28, 220072 Minsk, Belarus; (T.I.T.); (T.L.Y.); (A.F.P.)
| | - Elena A. Gondarenko
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, ul. Miklukho-Maklaya 16/10, 117997 Moscow, Russia; (A.V.O.); (E.V.K.); (D.S.K.); (N.V.K.); (E.A.G.); (M.N.Z.); (V.I.T.)
| | - Maxim N. Zhmak
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, ul. Miklukho-Maklaya 16/10, 117997 Moscow, Russia; (A.V.O.); (E.V.K.); (D.S.K.); (N.V.K.); (E.A.G.); (M.N.Z.); (V.I.T.)
| | - Victor I. Tsetlin
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, ul. Miklukho-Maklaya 16/10, 117997 Moscow, Russia; (A.V.O.); (E.V.K.); (D.S.K.); (N.V.K.); (E.A.G.); (M.N.Z.); (V.I.T.)
| | - Yuri N. Utkin
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, ul. Miklukho-Maklaya 16/10, 117997 Moscow, Russia; (A.V.O.); (E.V.K.); (D.S.K.); (N.V.K.); (E.A.G.); (M.N.Z.); (V.I.T.)
- Correspondence: or ; Tel.: +7-495-3366522
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21
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Hone AJ, Kaas Q, Kearns I, Hararah F, Gajewiak J, Christensen S, Craik DJ, McIntosh JM. Computational and Functional Mapping of Human and Rat α6β4 Nicotinic Acetylcholine Receptors Reveals Species-Specific Ligand-Binding Motifs. J Med Chem 2021; 64:1685-1700. [PMID: 33523678 PMCID: PMC8382285 DOI: 10.1021/acs.jmedchem.0c01973] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Nicotinic acetylcholine receptors (nAChRs) are pharmacological targets for the treatment of neuropathic pain, and the α6β4 subtype has been identified as particularly promising. Rat α6β4 nAChRs are less sensitive to some ligands than the human homologue potentially complicating the use of rodent α6β4 receptors for screening therapeutic compounds. We used molecular dynamics simulations coupled with functional assays to study the interaction between α-conotoxin PeIA and α6β4 nAChRs and to identify key ligand-receptor interactions that contribute to species differences in α-conotoxin potency. Our results show that human and rat α6β4 nAChRs have distinct ligand-binding motifs and show markedly different sensitivities to α-conotoxins. These studies facilitated the creation of PeIA-5667, a peptide that shows 270-fold higher potency for rat α6β4 nAChRs over native PeIA and similar potency for the human homologue. Our results may inform the design of therapeutic ligands that target α6β4 nAChRs for the treatment of neuropathic pain.
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Affiliation(s)
- Arik J Hone
- MIRECC, George E. Whalen Veterans Affairs Medical Center, Salt Lake City, Utah 84148 United States
| | - Quentin Kaas
- Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, Queensland 4072 Australia
| | | | | | | | | | - David J Craik
- Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, Queensland 4072 Australia
| | - J Michael McIntosh
- George E. Whalen Veterans Affairs Medical Center, Salt Lake City, Utah 84148 United States
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22
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Zhu X, Pan S, Xu M, Zhang L, Yu J, Yu J, Wu Y, Fan Y, Li H, Kasheverov IE, Kudryavtsev DS, Tsetlin VI, Xue Y, Zhangsun D, Wang X, Luo S. High Selectivity of an α-Conotoxin LvIA Analogue for α3β2 Nicotinic Acetylcholine Receptors Is Mediated by β2 Functionally Important Residues. J Med Chem 2020; 63:13656-13668. [PMID: 33196189 DOI: 10.1021/acs.jmedchem.0c00975] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The α3β2 and α3β4 nicotinic acetylcholine receptors (nAChRs) are widely expressed in the central and peripheral nervous systems, playing critical roles in various physiological processes and in such pathologies as addiction to nicotine and other drugs of abuse. α-Conotoxin LvIA, which we previously isolated from Conus lividus, modestly discriminates α3β2 and α3β4 rat nAChRs exhibiting a ∼17-fold tighter binding to the former. Here, alanine scanning resulted in two more selective analogues [N9A]LvIA and [D11A]LvIA, the former having a >2000-fold higher selectivity for α3β2. The determined crystal structures of [N9A]LvIA and [D11A]LvIA bound to the acetylcholine-binding protein (AChBP) were followed by homologous modeling of the complexes with the α3β2 and α3β4 nAChRs and by receptor mutagenesis, which revealed Phe106, Ser108, Ser113, and Ser168 residues in the β2 subunit as essential for LvIA binding. These results may be useful for the design of novel compounds of therapeutic potential targeting α3β2 nAChRs.
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Affiliation(s)
- Xiaopeng Zhu
- Medical School, Guangxi University, Nanning 530004, China.,Key Laboratory of Tropical Biological Resources of Ministry of Education, Key Laboratory for Marine Drugs of Haikou, School of Life and Pharmaceutical Sciences, Hainan University, Haikou 570228, China
| | - Si Pan
- The Ministry of Education Key Laboratory of Protein Science, School of Life Sciences, Beijing Advanced Innovation Center for Structural Biology, Collaborative Innovation Center for Biotherapy, Tsinghua University, Beijing 100084, China
| | - Manyu Xu
- The Ministry of Education Key Laboratory of Protein Science, School of Life Sciences, Beijing Advanced Innovation Center for Structural Biology, Collaborative Innovation Center for Biotherapy, Tsinghua University, Beijing 100084, China
| | - Lu Zhang
- Key Laboratory of Tropical Biological Resources of Ministry of Education, Key Laboratory for Marine Drugs of Haikou, School of Life and Pharmaceutical Sciences, Hainan University, Haikou 570228, China
| | - Jinfang Yu
- The Ministry of Education Key Laboratory of Protein Science, School of Life Sciences, Beijing Advanced Innovation Center for Structural Biology, Collaborative Innovation Center for Biotherapy, Tsinghua University, Beijing 100084, China
| | - Jinpeng Yu
- Medical School, Guangxi University, Nanning 530004, China
| | - Yong Wu
- Medical School, Guangxi University, Nanning 530004, China
| | - Yingxu Fan
- Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Haonan Li
- Key Laboratory of Tropical Biological Resources of Ministry of Education, Key Laboratory for Marine Drugs of Haikou, School of Life and Pharmaceutical Sciences, Hainan University, Haikou 570228, China
| | - Igor E Kasheverov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya Street 16/10, Moscow 117997, Russia.,Sechenov First Moscow State Medical University, Institute of Molecular Medicine, Trubetskaya Street 8, bld. 2, Moscow 119991, Russia
| | - Denis S Kudryavtsev
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya Street 16/10, Moscow 117997, Russia
| | - Victor I Tsetlin
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya Street 16/10, Moscow 117997, Russia.,PhysBio of MePhi, Kashirskoe Ave. 31, Moscow 115409, Russia
| | - Yi Xue
- Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Dongting Zhangsun
- Medical School, Guangxi University, Nanning 530004, China.,Key Laboratory of Tropical Biological Resources of Ministry of Education, Key Laboratory for Marine Drugs of Haikou, School of Life and Pharmaceutical Sciences, Hainan University, Haikou 570228, China
| | - Xinquan Wang
- The Ministry of Education Key Laboratory of Protein Science, School of Life Sciences, Beijing Advanced Innovation Center for Structural Biology, Collaborative Innovation Center for Biotherapy, Tsinghua University, Beijing 100084, China
| | - Sulan Luo
- Medical School, Guangxi University, Nanning 530004, China.,Key Laboratory of Tropical Biological Resources of Ministry of Education, Key Laboratory for Marine Drugs of Haikou, School of Life and Pharmaceutical Sciences, Hainan University, Haikou 570228, China
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23
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Giribaldi J, Haufe Y, Evans ERJ, Amar M, Durner A, Schmidt C, Faucherre A, Moha Ou Maati H, Enjalbal C, Molgó J, Servent D, Wilson DT, Daly NL, Nicke A, Dutertre S. Backbone Cyclization Turns a Venom Peptide into a Stable and Equipotent Ligand at Both Muscle and Neuronal Nicotinic Receptors. J Med Chem 2020; 63:12682-12692. [DOI: 10.1021/acs.jmedchem.0c00957] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Julien Giribaldi
- Institut des Biomolécules Max Mousseron, Université de Montpellier, CNRS, ENSCM, 34095 Montpellier, France
| | - Yves Haufe
- Walther Straub Institute of Pharmacology and Toxicology, Faculty of Medicine, LMU Munich, Nußbaumstraße 26, 80336 Munich, Germany
| | - Edward R. J. Evans
- Centre for Molecular Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, Queensland 4878, Australia
| | - Muriel Amar
- Département Médicaments et Technologies pour la Santé (DMTS), Université Paris-Saclay, CEA, SIMoS, ERL CNRS 9004, F-91191 Gif sur Yvette, France
| | - Anna Durner
- Walther Straub Institute of Pharmacology and Toxicology, Faculty of Medicine, LMU Munich, Nußbaumstraße 26, 80336 Munich, Germany
| | - Casey Schmidt
- Centre for Molecular Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, Queensland 4878, Australia
| | - Adèle Faucherre
- Département de Physiologie, Institut de Génomique Fonctionnelle, CNRS/INSERM UMR 5203, Université de Montpellier, 34095 Montpellier, France
| | - Hamid Moha Ou Maati
- Département de Physiologie, Institut de Génomique Fonctionnelle, CNRS/INSERM UMR 5203, Université de Montpellier, 34095 Montpellier, France
| | - Christine Enjalbal
- Institut des Biomolécules Max Mousseron, Université de Montpellier, CNRS, ENSCM, 34095 Montpellier, France
| | - Jordi Molgó
- Département Médicaments et Technologies pour la Santé (DMTS), Université Paris-Saclay, CEA, SIMoS, ERL CNRS 9004, F-91191 Gif sur Yvette, France
| | - Denis Servent
- Département Médicaments et Technologies pour la Santé (DMTS), Université Paris-Saclay, CEA, SIMoS, ERL CNRS 9004, F-91191 Gif sur Yvette, France
| | - David T. Wilson
- Centre for Molecular Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, Queensland 4878, Australia
| | - Norelle L. Daly
- Centre for Molecular Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, Queensland 4878, Australia
| | - Annette Nicke
- Walther Straub Institute of Pharmacology and Toxicology, Faculty of Medicine, LMU Munich, Nußbaumstraße 26, 80336 Munich, Germany
| | - Sébastien Dutertre
- Institut des Biomolécules Max Mousseron, Université de Montpellier, CNRS, ENSCM, 34095 Montpellier, France
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24
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Kennedy AC, Belgi A, Husselbee BW, Spanswick D, Norton RS, Robinson AJ. α-Conotoxin Peptidomimetics: Probing the Minimal Binding Motif for Effective Analgesia. Toxins (Basel) 2020; 12:E505. [PMID: 32781580 PMCID: PMC7472027 DOI: 10.3390/toxins12080505] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 07/29/2020] [Accepted: 08/03/2020] [Indexed: 12/18/2022] Open
Abstract
Several analgesic α-conotoxins have been isolated from marine cone snails. Structural modification of native peptides has provided potent and selective analogues for two of its known biological targets-nicotinic acetylcholine and γ-aminobutyric acid (GABA) G protein-coupled (GABAB) receptors. Both of these molecular targets are implicated in pain pathways. Despite their small size, an incomplete understanding of the structure-activity relationship of α-conotoxins at each of these targets has hampered the development of therapeutic leads. This review scrutinises the N-terminal domain of the α-conotoxin family of peptides, a region defined by an invariant disulfide bridge, a turn-inducing proline residue and multiple polar sidechain residues, and focusses on structural features that provide analgesia through inhibition of high-voltage-activated Ca2+ channels. Elucidating the bioactive conformation of this region of these peptides may hold the key to discovering potent drugs for the unmet management of debilitating chronic pain associated with a wide range of medical conditions.
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Affiliation(s)
- Adam C. Kennedy
- School of Chemistry, Monash University, Clayton, Victoria 3800, Australia; (A.C.K.); (A.B.); (B.W.H.)
| | - Alessia Belgi
- School of Chemistry, Monash University, Clayton, Victoria 3800, Australia; (A.C.K.); (A.B.); (B.W.H.)
| | - Benjamin W. Husselbee
- School of Chemistry, Monash University, Clayton, Victoria 3800, Australia; (A.C.K.); (A.B.); (B.W.H.)
| | - David Spanswick
- Biomedicine Discovery Institute and the Department of Physiology, Monash University, Victoria 3800, Australia;
- Warwick Medical School, University of Warwick, Coventry CV4 7AL, UK
- NeuroSolutions Ltd., Coventry CV4 7AL, UK
| | - Raymond S. Norton
- Medicinal Chemistry, Monash Institute of Pharmaceutical Science, Monash University, 381 Royal Parade, Parkville, Victoria 3052, Australia;
- ARC Centre for Fragment-Based Design, Monash University, Parkville, Victoria 3052, Australia
| | - Andrea J. Robinson
- School of Chemistry, Monash University, Clayton, Victoria 3800, Australia; (A.C.K.); (A.B.); (B.W.H.)
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25
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Interactions of the α3β2 Nicotinic Acetylcholine Receptor Interfaces with α-Conotoxin LsIA and its Carboxylated C-terminus Analogue: Molecular Dynamics Simulations. Mar Drugs 2020; 18:md18070349. [PMID: 32635340 PMCID: PMC7401271 DOI: 10.3390/md18070349] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Revised: 06/27/2020] [Accepted: 06/30/2020] [Indexed: 12/22/2022] Open
Abstract
Notably, α-conotoxins with carboxy-terminal (C-terminal) amidation are inhibitors of the pentameric nicotinic acetylcholine receptors (nAChRs), which are therapeutic targets for neurological diseases and disorders. The (α3)2(β2)3 nAChR subunit arrangement comprises a pair of α3(+)β2(−) and β2(+)α3(−) interfaces, and a β2(+)β2(−) interface. The β2(+)β2(−) interface has been suggested to have higher agonist affinity relative to the α3(+)β2(−) and β2(+)α3(−) interfaces. Nevertheless, the interactions formed by these subunit interfaces with α-conotoxins are not well understood. Therefore, in order to address this, we modelled the interactions between α-conotoxin LsIA and the α3β2 subtype. The results suggest that the C-terminal carboxylation of LsIA predominantly influenced the enhanced contacts of the conotoxin via residues P7, P14 and C17 on LsIA at the α3(+)β2(−) and β2(+)α3(−) interfaces. However, this enhancement is subtle at the β2(+)β2(−) site, which can compensate the augmented interactions by LsIA at α3(+)β2(−) and β2(+)α3(−) binding sites. Therefore, the divergent interactions at the individual binding interface may account for the minor changes in binding affinity to α3β2 subtype by C-terminal carboxylation of LsIA versus its wild type, as shown in previous experimental results. Overall, these findings may facilitate the development of new drug leads or subtype-selective probes.
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26
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Hone AJ, Rueda-Ruzafa L, Gordon TJ, Gajewiak J, Christensen S, Dyhring T, Albillos A, McIntosh JM. Expression of α3β2β4 nicotinic acetylcholine receptors by rat adrenal chromaffin cells determined using novel conopeptide antagonists. J Neurochem 2020; 154:158-176. [PMID: 31967330 DOI: 10.1111/jnc.14966] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 12/17/2019] [Accepted: 01/13/2020] [Indexed: 01/07/2023]
Abstract
Adrenal chromaffin cells release neurotransmitters in response to stress and may be involved in conditions such as post-traumatic stress and anxiety disorders. Neurotransmitter release is triggered, in part, by activation of nicotinic acetylcholine receptors (nAChRs). However, despite decades of use as a model system for studying exocytosis, the nAChR subtypes involved have not been pharmacologically identified. Quantitative real-time PCR of rat adrenal medulla revealed an abundance of mRNAs for α3, α7, β2, and β4 subunits. Whole-cell patch-clamp electrophysiology of chromaffin cells and subtype-selective ligands were used to probe for nAChRs derived from the mRNAs found in adrenal medulla. A novel conopeptide antagonist, PeIA-5469, was created that is highly selective for α3β2 over other nAChR subtypes heterologously expressed in Xenopus laevis oocytes. Experiments using PeIA-5469 and the α3β4-selective α-conotoxin TxID revealed that rat adrenal medulla contain two populations of chromaffin cells that express either α3β4 nAChRs alone or α3β4 together with the α3β2β4 subtype. Conclusions were derived from observations that acetylcholine-gated currents in some cells were sensitive to inhibition by PeIA-5469 and TxID, while in other cells, currents were sensitive only to TxID. Expression of functional α7 nAChRs was determined using three α7-selective ligands: the agonist PNU282987, the positive allosteric modulator PNU120596, and the antagonist α-conotoxin [V11L,V16D]ArIB. The results of these studies identify for the first time the expression of α3β2β4 nAChRs as well as functional α7 nAChRs by rat adrenal chromaffin cells.
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Affiliation(s)
- Arik J Hone
- George E. Whalen Veterans Affairs Medical Center, Salt Lake City, Utah, USA.,School of Biological Sciences and University of Utah, Salt Lake City, Utah, USA.,Departament of Pharmacology and Therapeutics, Universidad Autónoma de Madrid, Madrid, Spain
| | - Lola Rueda-Ruzafa
- Departament of Pharmacology and Therapeutics, Universidad Autónoma de Madrid, Madrid, Spain.,Biomedical Research Center (CINBIO), University of Vigo, Vigo, Spain
| | - Thomas J Gordon
- School of Biological Sciences and University of Utah, Salt Lake City, Utah, USA
| | - Joanna Gajewiak
- School of Biological Sciences and University of Utah, Salt Lake City, Utah, USA
| | - Sean Christensen
- School of Biological Sciences and University of Utah, Salt Lake City, Utah, USA
| | | | - Almudena Albillos
- Departament of Pharmacology and Therapeutics, Universidad Autónoma de Madrid, Madrid, Spain
| | - J Michael McIntosh
- George E. Whalen Veterans Affairs Medical Center, Salt Lake City, Utah, USA.,School of Biological Sciences and University of Utah, Salt Lake City, Utah, USA.,Department of Psychiatry, University of Utah, Salt Lake City, Utah, USA
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27
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Marquart LA, Turner MW, McDougal OM. Qualitative Assay to Detect Dopamine Release by Ligand Action on Nicotinic Acetylcholine Receptors. Toxins (Basel) 2019; 11:toxins11120682. [PMID: 31757080 PMCID: PMC6949981 DOI: 10.3390/toxins11120682] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 11/14/2019] [Accepted: 11/18/2019] [Indexed: 11/16/2022] Open
Abstract
A pheochromocytoma of the rat adrenal medulla derived (a.k.a. PC12) cell-based assay for dopamine measurement by luminescence detection was customized for the qualitative evaluation of agonists and antagonists of nicotinic acetylcholine receptors (nAChRs). The assay mechanism begins with ligand binding to transmembrane nAChRs, altering ion flow into the cell and inducing dopamine release from the cell. Following release, dopamine is oxidized by monoamine oxidase generating hydrogen peroxide that catalyzes a chemiluminescence reaction involving luminol and horseradish peroxidase, thus producing a detectable response. Results are presented for the action of nAChR agonists (acetylcholine, nicotine, and cytisine), and antagonists (α-conotoxins (α-CTxs) MII, ImI, LvIA, and PeIA) that demonstrate a luminescence response correlating to the increase or decrease of dopamine release. A survey of cell growth and treatment conditions, including nerve growth factor, nicotine, ethanol, and temperature, led to optimal assay requirements to achieve maximal signal intensity and consistent response to ligand treatment. It was determined that PC12 cells treated with a combination of nerve growth factor and nicotine, and incubated at 37 °C, provided favorable results for a reduction in luminescence signal upon treatment of cells with α-CTxs. The PC12 assay is intended for use as a fast, efficient, and economic qualitative method to assess the bioactivity of molecules that act on nAChRs, in which testing of ligand-nAChR binding hypotheses and computational predictions can be validated. As a screening method for nAChR bioactivity, lead compounds can be assessed for their likelihood of exhibiting desired bioactivity prior to being subjected to more complex quantitative methods, such as electrophysiology or live animal studies.
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Affiliation(s)
- Leanna A. Marquart
- Department of Chemistry and Biochemistry, Boise State University, Boise, ID 83725, USA;
| | - Matthew W. Turner
- Biomolecular Sciences PhD Program, Boise State University, Boise, ID 83725, USA;
| | - Owen M. McDougal
- Biomolecular Sciences PhD Program, Boise State University, Boise, ID 83725, USA;
- Correspondence:
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28
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Peigneur S, Devi P, Seldeslachts A, Ravichandran S, Quinton L, Tytgat J. Structure-Function Elucidation of a New α-Conotoxin, MilIA, from Conus milneedwardsi. Mar Drugs 2019; 17:md17090535. [PMID: 31527432 PMCID: PMC6780063 DOI: 10.3390/md17090535] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Revised: 09/05/2019] [Accepted: 09/07/2019] [Indexed: 12/16/2022] Open
Abstract
The a-Conotoxins are peptide toxins that are found in the venom of marine cone snails and they are potent antagonists of various subtypes of nicotinic acetylcholine receptors (nAChRs). Because nAChRs have an important role in regulating transmitter release, cell excitability, and neuronal integration, nAChR dysfunctions have been implicated in a variety of severe pathologies. We describe the isolation and characterization of α-conotoxin MilIA, the first conopeptide from the venom of Conus milneedwardsi. The peptide was characterized by electrophysiological screening against several types of cloned nAChRs that were expressed in Xenopus laevis oocytes. MilIA, which is a member of the α3/5 family, is an antagonist of muscle type nAChRs with a high selectivity for muscle versus neuronal subtype nAChRs. Several analogues were designed and investigated for their activity in order to determine the key epitopes of MilIA. Native MilIA and analogues both showed activity at the fetal muscle type nAChR. Two single mutations (Met9 and Asn10) allowed for MilIA to strongly discriminate between the two types of muscle nAChRs. Moreover, one analogue, MilIA [∆1,M2R, M9G, N10K, H11K], displayed a remarkable enhanced potency when compared to native peptide. The key residues that are responsible for switching between muscle and neuronal nAChRs preference were elucidated. Interestingly, the same analogue showed a preference for α9α10 nAChRs among the neuronal types.
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Affiliation(s)
- Steve Peigneur
- Toxicology and Pharmacology, KU Leuven, Campus Gasthuisberg, O & N2, Herestraat 49, P.O. Box 922, 3000 Leuven, Belgium.
| | - Prabha Devi
- Toxicology and Pharmacology, KU Leuven, Campus Gasthuisberg, O & N2, Herestraat 49, P.O. Box 922, 3000 Leuven, Belgium.
- CSIR-National Institute of Oceanography, Dona Paula, Goa 403 004, India.
| | - Andrea Seldeslachts
- Toxicology and Pharmacology, KU Leuven, Campus Gasthuisberg, O & N2, Herestraat 49, P.O. Box 922, 3000 Leuven, Belgium.
| | | | - Loïc Quinton
- Laboratory of Mass Spectrometry, Department of Chemistry, University of Liège, 4000 Liège, Belgium.
| | - Jan Tytgat
- Toxicology and Pharmacology, KU Leuven, Campus Gasthuisberg, O & N2, Herestraat 49, P.O. Box 922, 3000 Leuven, Belgium.
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α-Conotoxin TxIB: A Uniquely Selective Ligand for α6/α3β2β3 Nicotinic Acetylcholine Receptor Attenuates Nicotine-Induced Conditioned Place Preference in Mice. Mar Drugs 2019; 17:md17090490. [PMID: 31443523 PMCID: PMC6780885 DOI: 10.3390/md17090490] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2019] [Revised: 08/17/2019] [Accepted: 08/20/2019] [Indexed: 11/17/2022] Open
Abstract
α-Conotoxin TxIB is a specific antagonist of α6/α3β2β3(α6β2*) nicotinic acetylcholine receptor (nAChR) with an IC50 of 28 nM. Previous studies have shown that α6β2* nAChRs are abundantly expressed in midbrain dopaminergic neurons and play an important role in mediating the mechanism of nicotine and other drugs reward effect. It provided important targets for the development of anti-addiction drugs. The present study evaluated the pharmacological activity of TxIB in vivo with conditioned place preference (CPP) model, which were induced by subcutaneous injection (s.c.) of nicotine (NIC, 0.5 mg/kg). α-Conotoxin TxIB inhibited the expression and reinstatement of CPP in mice dose-dependently, but had no significant effect on locomotor activity. The concentrations of dopamine (DA), γ-aminobutyric acid (GABA) and noradrenaline (NE) in different brain regions were measured by enzyme-linked immunosorbent assay (ELISA). We found that TxIB could inhibit the concentrations of DA, GABA and NE in different brain regions (such as nucleus accumbens (NAc), hippocampus (HIP) and prefrontal cortex (PFC)) in NIC-induced mice. The concentrations of DA and NE were decreased in ventral tegmental area (VTA), while GABA had little change. The current work described the inhibition activity of TxIB in NIC-induced CPP, suggesting that α6β2* nAChR-targeted compound may be a promising drug for nicotine addiction treatment.
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van Hout M, Valdes A, Christensen SB, Tran PT, Watkins M, Gajewiak J, Jensen AA, Olivera BM, McIntosh JM. α-Conotoxin VnIB from Conus ventricosus is a potent and selective antagonist of α6β4* nicotinic acetylcholine receptors. Neuropharmacology 2019; 157:107691. [PMID: 31255696 DOI: 10.1016/j.neuropharm.2019.107691] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 06/05/2019] [Accepted: 06/26/2019] [Indexed: 01/20/2023]
Abstract
α6-containing (α6*) nicotinic acetylcholine receptors (nAChRs) are expressed throughout the periphery and the central nervous system and constitute putative therapeutic targets in pain, addiction and movement disorders. The α6β2* nAChRs are relatively well studied, in part due to the availability of target specific α-conotoxins (α-Ctxs). In contrast, all native α-Ctxs identified that potently block α6β4 nAChRs exhibit higher potencies for the closely related α6β2β3 and/or α3β4 subtypes. In this study, we have identified a novel peptide from Conus ventricosus with pronounced selectivity for the α6β4 nAChR. The peptide-encoding gene was cloned from genomic DNA and the predicted mature peptide, α-Ctx VnIB, was synthesized. The functional properties of VnIB were characterized at rat and human nAChRs expressed in Xenopus oocytes by two-electrode voltage clamp electrophysiology. VnIB potently inhibited ACh-evoked currents at rα6β4 and rα6/α3β4 nAChRs, displayed ∼20-fold and ∼250-fold lower potencies at rα3β4 and rα6/α3β2β3 receptors, respectively, and exhibited negligible effects at eight other nAChR subtypes. Interestingly, even higher degrees of selectivity were observed for hα6/α3β4 over hα6/α3β2β3 and hα3β4 receptors. Finally, VnIB displayed fast binding kinetics at rα6/α3β4 (on-rate t½ = 0.87 min-1, off-rate t½ = 2.7 min-1). The overall preference of VnIB for β4* over β2* nAChRs is similar to the selectivity profiles of other 4/6 α-Ctxs. However, in contrast to previously identified native α-Ctxs targeting α6* nAChRs, VnIB displays pronounced selectivity for α6β4 nAChRs over both α3β4 and α6β2β3 receptors. VnIB thus represents a novel molecular probe for elucidating the physiological role and therapeutic properties of α6β4* nAChRs.
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Affiliation(s)
- Marloes van Hout
- Department of Biology, University of Utah, Salt Lake City, UT, 84112, USA; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
| | - Amanda Valdes
- Department of Biology, University of Utah, Salt Lake City, UT, 84112, USA
| | - Sean B Christensen
- Department of Biology, University of Utah, Salt Lake City, UT, 84112, USA.
| | - Phuong T Tran
- Department of Biology, University of Utah, Salt Lake City, UT, 84112, USA
| | - Maren Watkins
- Department of Biology, University of Utah, Salt Lake City, UT, 84112, USA; Department of Pathology, University of Utah, Salt Lake City, UT, 84112, USA.
| | - Joanna Gajewiak
- Department of Biology, University of Utah, Salt Lake City, UT, 84112, USA.
| | - Anders A Jensen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
| | | | - J Michael McIntosh
- Department of Biology, University of Utah, Salt Lake City, UT, 84112, USA; Department of Psychiatry, University of Utah, Salt Lake City, UT, 84108, USA; George E. Wahlen Veterans Affair Medical Center, Salt Lake City, UT, 84148, USA.
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31
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Hone AJ, Fisher F, Christensen S, Gajewiak J, Larkin D, Whiteaker P, McIntosh JM. PeIA-5466: A Novel Peptide Antagonist Containing Non-natural Amino Acids That Selectively Targets α3β2 Nicotinic Acetylcholine Receptors. J Med Chem 2019; 62:6262-6275. [PMID: 31194549 DOI: 10.1021/acs.jmedchem.9b00566] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Pharmacologically distinguishing α3β2 nicotinic acetylcholine receptors (nAChRs) from closely related subtypes, particularly α6β2, has been challenging due to the lack of subtype-selective ligands. We created analogs of α-conotoxin (α-Ctx) PeIA to identify ligand-receptor interactions that could be exploited to selectively increase potency and selectivity for α3β2 nAChRs. A series of PeIA analogs were synthesized by replacing amino acid residues in the second disulfide loop with standard or nonstandard residues and assessing their activity on α3β2 and α6/α3β2β3 nAChRs heterologously expressed in Xenopus laevis oocytes. Asparagine11 was found to occupy a pivotal position, and when replaced with negatively charged amino acids, selectivity for α3β2 over α6/α3β2β3 nAChRs was substantially increased. Second generation peptides were then designed to further improve both potency and selectivity. One peptide, PeIA-5466, was ∼300-fold more potent on α3β2 than α6/α3β2β3 and is the most α3β2-selective antagonist heretofore reported.
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Affiliation(s)
| | | | | | | | | | | | - J Michael McIntosh
- George E. Whalen Veterans Affairs Medical Center , Salt Lake City , Utah 84148 , United States
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32
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Morales Duque H, Campos Dias S, Franco OL. Structural and Functional Analyses of Cone Snail Toxins. Mar Drugs 2019; 17:md17060370. [PMID: 31234371 PMCID: PMC6628382 DOI: 10.3390/md17060370] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Revised: 06/16/2019] [Accepted: 06/17/2019] [Indexed: 12/12/2022] Open
Abstract
Cone snails are marine gastropod mollusks with one of the most powerful venoms in nature. The toxins, named conotoxins, must act quickly on the cone snails´ prey due to the fact that snails are extremely slow, reducing their hunting capability. Therefore, the characteristics of conotoxins have become the object of investigation, and as a result medicines have been developed or are in the trialing process. Conotoxins interact with transmembrane proteins, showing specificity and potency. They target ion channels and ionotropic receptors with greater regularity, and when interaction occurs, there is immediate physiological decompensation. In this review we aimed to evaluate the structural features of conotoxins and the relationship with their target types.
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Affiliation(s)
- Harry Morales Duque
- Centro de Análises Proteômicas e Bioquímicas, Programa de Pós-Graduação em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília, Brasília-DF 70.790-160, Brazil.
| | - Simoni Campos Dias
- Centro de Análises Proteômicas e Bioquímicas, Programa de Pós-Graduação em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília, Brasília-DF 70.790-160, Brazil.
| | - Octávio Luiz Franco
- Centro de Análises Proteômicas e Bioquímicas, Programa de Pós-Graduação em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília, Brasília-DF 70.790-160, Brazil.
- S-inova Biotech, Programa de Pós-Graduação em Biotecnologia, Universidade Católica Dom Bosco, Campo Grande-MS 79.117-900, Brazil.
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33
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Turner MW, Marquart LA, Phillips PD, McDougal OM. Mutagenesis of α-Conotoxins for Enhancing Activity and Selectivity for Nicotinic Acetylcholine Receptors. Toxins (Basel) 2019; 11:E113. [PMID: 30781866 PMCID: PMC6409848 DOI: 10.3390/toxins11020113] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2019] [Revised: 02/10/2019] [Accepted: 02/11/2019] [Indexed: 02/04/2023] Open
Abstract
Nicotinic acetylcholine receptors (nAChRs) are found throughout the mammalian body and have been studied extensively because of their implication in a myriad of diseases. α-Conotoxins (α-CTxs) are peptide neurotoxins found in the venom of marine snails of genus Conus. α-CTxs are potent and selective antagonists for a variety of nAChR isoforms. Over the past 40 years, α-CTxs have proven to be valuable molecular probes capable of differentiating between closely related nAChR subtypes and have contributed greatly to understanding the physiological role of nAChRs in the mammalian nervous system. Here, we review the amino acid composition and structure of several α-CTxs that selectively target nAChR isoforms and explore strategies and outcomes for introducing mutations in native α-CTxs to direct selectivity and enhance binding affinity for specific nAChRs. This review will focus on structure-activity relationship studies involving native α-CTxs that have been rationally mutated and molecular interactions that underlie binding between ligand and nAChR isoform.
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Affiliation(s)
- Matthew W Turner
- Biomolecular Sciences Graduate Programs, Boise State University; Boise, ID 83725, USA.
| | - Leanna A Marquart
- Department of Chemistry and Biochemistry, Boise State University; Boise, ID 83725, USA.
| | - Paul D Phillips
- Department of Chemistry and Biochemistry, Boise State University; Boise, ID 83725, USA.
| | - Owen M McDougal
- Department of Chemistry and Biochemistry, Boise State University; Boise, ID 83725, USA.
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34
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Grau V, Richter K, Hone AJ, McIntosh JM. Conopeptides [V11L;V16D]ArIB and RgIA4: Powerful Tools for the Identification of Novel Nicotinic Acetylcholine Receptors in Monocytes. Front Pharmacol 2019; 9:1499. [PMID: 30687084 PMCID: PMC6338043 DOI: 10.3389/fphar.2018.01499] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Accepted: 12/07/2018] [Indexed: 12/27/2022] Open
Abstract
Venomous marine snails of the genus Conus employ small peptides to capture prey, mainly osteichthyes, mollusks, and worms. A subset of these peptides known as α-conotoxins, are antagonists of nicotinic acetylcholine receptors (nAChRs). These disulfide-rich peptides provide a large number of evolutionarily refined templates that can be used to develop conopeptides that are highly selective for the various nAChR subtypes. Two such conopeptides, namely [V11L;V16D]ArIB and RgIA4, have been engineered to selectively target mammalian α7∗ and α9∗ nAChRs, respectively, and have been used to study the functional roles of these subtypes in immune cells. Unlike in neurons and cochlear hair cells, where α7∗ and α9∗ nAChRs, respectively, function as ligand-gated ion channels, in immune cells ligand-evoked ion currents have not been demonstrated. Instead, different metabotropic functions of α7∗ and α9∗ nAChRs have been described in monocytic cells including the inhibition of ATP-induced ion currents, inflammasome activation, and interleukin-1β (IL-1β) release. In addition to conventional nAChR agonists, diverse compounds containing a phosphocholine group inhibit monocytic IL-1β release and include dipalmitoyl phosphatidylcholine, palmitoyl lysophosphatidylcholine, glycerophosphocholine, phosphocholine, phosphocholine-decorated lipooligosaccharides from Haemophilus influenzae, synthetic phosphocholine-modified bovine serum albumin, and the phosphocholine-binding C-reactive protein. In monocytic cells, the effects of [V11L;V16D]ArIB and RgIA4 suggested that activation of nAChRs containing α9, α7, and/or α10 subunits inhibits ATP-induced IL-1β release. These results have been corroborated utilizing gene-deficient mice and small interfering RNA. Targeted re-engineering of native α-conotoxins has resulted in excellent tools for nAChR research as well as potential therapeutics. ∗indicates possible presence of additional subunits.
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Affiliation(s)
- Veronika Grau
- Laboratory of Experimental Surgery, Department of General and Thoracic Surgery, German Centre for Lung Research (DZL), Giessen University, Giessen, Germany
| | - Katrin Richter
- Laboratory of Experimental Surgery, Department of General and Thoracic Surgery, German Centre for Lung Research (DZL), Giessen University, Giessen, Germany
| | - Arik J Hone
- Department of Biology, University of Utah, Salt Lake City, UT, United States
| | - J Michael McIntosh
- Department of Biology, University of Utah, Salt Lake City, UT, United States.,George E. Wahlen Department of Veterans Affairs Medical Center, Salt Lake City, UT, United States.,Department of Psychiatry, University of Utah, Salt Lake City, UT, United States
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35
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Chen DJ, Gao FF, Ma XK, Shi GG, Huang YB, Su QX, Sudweeks S, Gao M, Dharshaun T, Eaton JB, Chang YC, Mcintosh JM, Lukas RJ, Whiteaker P, Steffensen SC, Wu J. Pharmacological and functional comparisons of α6/α3β2β3-nAChRs and α4β2-nAChRs heterologously expressed in the human epithelial SH-EP1 cell line. Acta Pharmacol Sin 2018; 39:1571-1581. [PMID: 29795357 PMCID: PMC6289390 DOI: 10.1038/aps.2017.209] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2017] [Accepted: 12/21/2017] [Indexed: 02/05/2023] Open
Abstract
Neuronal nicotinic acetylcholine receptors containing α6 subunits (α6*-nAChRs) show highly restricted distribution in midbrain neurons associated with pleasure, reward, and mood control, suggesting an important impact of α6*-nAChRs in modulating mesolimbic functions. However, the function and pharmacology of α6*-nAChRs remain poorly understood because of the lack of selective agonists for α6*-nAChRs and the challenging heterologous expression of functional α6*-nAChRs in mammalian cell lines. In particular, the α6 subunit is commonly co-expressed with α4*-nAChRs in the midbrain, which masks α6*-nAChR (without α4) function and pharmacology. In this study, we systematically profiled the pharmacology and function of α6*-nAChRs and compared these properties with those of α4β2 nAChRs expressed in the same cell line. Heterologously expressed human α6/α3 chimeric subunits (α6 N-terminal domain joined with α3 trans-membrane domains and intracellular loops) with β2 and β3 subunits in the human SH-EP1 cell line (α6*-nAChRs) were used. Patch-clamp whole-cell recordings were performed to measure these receptor-mediated currents. Functionally, the heterologously expressed α6*-nAChRs exhibited excellent function and showed distinct nicotine-induced current responses, such as kinetics, inward rectification and recovery from desensitization, compared with α4β2-nAChRs. Pharmacologically, α6*-nAChR was highly sensitive to the α6 subunit-selective antagonist α-conotoxin MII but had lower sensitivity to mecamylamine and dihydro-β-erythroidine. Nicotine and acetylcholine were found to be full agonists for α6*-nAChRs, whereas epibatidine and cytisine were determined to be partial agonists. Heterologously expressed α6*-nAChRs exhibited pharmacology and function distinct from those of α4β2-nAChRs, suggesting that α6*-nAChRs may mediate different cholinergic signals. Our α6*-nAChR expression system can be used as an excellent cell model for future investigations of α6*-nAChR function and pharmacology.
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Affiliation(s)
- De-Jie Chen
- Department of Neurology, Yunfu People's Hospital, Yunfu, 527300, China
- Department of Neurobiology, Barrow Neurological Institute, St Joseph's Hospital and Medical Center, Phoenix, AZ, 85013, USA
| | - Fen-Fei Gao
- Department of Neurobiology, Barrow Neurological Institute, St Joseph's Hospital and Medical Center, Phoenix, AZ, 85013, USA
- Department of Pharmacology, Shantou University Medical College, Shantou, 515063, China
| | - Xiao-Kuang Ma
- Department of Neurobiology, Barrow Neurological Institute, St Joseph's Hospital and Medical Center, Phoenix, AZ, 85013, USA
- Department of Pharmacology, Shantou University Medical College, Shantou, 515063, China
| | - Gang-Gang Shi
- Department of Pharmacology, Shantou University Medical College, Shantou, 515063, China
| | - Yuan-Bing Huang
- Department of Neurology, Yunfu People's Hospital, Yunfu, 527300, China
- Department of Neurobiology, Barrow Neurological Institute, St Joseph's Hospital and Medical Center, Phoenix, AZ, 85013, USA
| | - Quang-Xi Su
- Department of Neurology, Yunfu People's Hospital, Yunfu, 527300, China
| | - Sterling Sudweeks
- Departments of Psychology and Developmental Biology, Brigham Young University, Provo, UT, 84602, USA
| | - Ming Gao
- Department of Neurobiology, Barrow Neurological Institute, St Joseph's Hospital and Medical Center, Phoenix, AZ, 85013, USA
| | - Turner Dharshaun
- Department of Neurobiology, Barrow Neurological Institute, St Joseph's Hospital and Medical Center, Phoenix, AZ, 85013, USA
| | - Jason Brek Eaton
- Department of Neurobiology, Barrow Neurological Institute, St Joseph's Hospital and Medical Center, Phoenix, AZ, 85013, USA
| | - Yong-Chang Chang
- Department of Neurobiology, Barrow Neurological Institute, St Joseph's Hospital and Medical Center, Phoenix, AZ, 85013, USA
| | - J Michael Mcintosh
- George E Wahlen Veterans Affairs Medical Center, Salt Lake City, UT, 84108, USA
- Departments of Psychiatry and Biology, University of Utah, Salt Lake City, UT, 84112, USA
| | - Ronald J Lukas
- Department of Neurobiology, Barrow Neurological Institute, St Joseph's Hospital and Medical Center, Phoenix, AZ, 85013, USA
| | - Paul Whiteaker
- Department of Neurobiology, Barrow Neurological Institute, St Joseph's Hospital and Medical Center, Phoenix, AZ, 85013, USA
| | - Scott C Steffensen
- Department of Physiology and Neuroscience, Brigham Young University, Provo, UT, 84602, USA
| | - Jie Wu
- Department of Neurology, Yunfu People's Hospital, Yunfu, 527300, China.
- Department of Neurobiology, Barrow Neurological Institute, St Joseph's Hospital and Medical Center, Phoenix, AZ, 85013, USA.
- Department of Pharmacology, Shantou University Medical College, Shantou, 515063, China.
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36
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Hone AJ, Talley TT, Bobango J, Huidobro Melo C, Hararah F, Gajewiak J, Christensen S, Harvey PJ, Craik DJ, McIntosh JM. Molecular determinants of α-conotoxin potency for inhibition of human and rat α6β4 nicotinic acetylcholine receptors. J Biol Chem 2018; 293:17838-17852. [PMID: 30249616 DOI: 10.1074/jbc.ra118.005649] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Revised: 09/20/2018] [Indexed: 12/15/2022] Open
Abstract
Nicotinic acetylcholine receptors (nAChRs) containing α6 and β4 subunits are expressed by dorsal root ganglion neurons and have been implicated in neuropathic pain. Rodent models are often used to evaluate the efficacy of analgesic compounds, but species differences may affect the activity of some nAChR ligands. A previous candidate α-conotoxin-based therapeutic yielded promising results in rodent models, but failed in human clinical trials, emphasizing the importance of understanding species differences in ligand activity. Here, we show that human and rat α6/α3β4 nAChRs expressed in Xenopus laevis oocytes exhibit differential sensitivity to α-conotoxins. Sequence homology comparisons of human and rat α6β4 nAChR subunits indicated that α6 residues forming the ligand-binding pocket are highly conserved between the two species, but several residues of β4 differed, including a Leu-Gln difference at position 119. X-ray crystallography of α-conotoxin PeIA complexed with the Aplysia californica acetylcholine-binding protein (AChBP) revealed that binding of PeIA orients Pro13 in close proximity to residue 119 of the AChBP complementary subunit. Site-directed mutagenesis studies revealed that Leu119 of human β4 contributes to higher sensitivity of human α6/α3β4 nAChRs to α-conotoxins, and structure-activity studies indicated that PeIA Pro13 is critical for high potency. Human and rat α6/α3β4 nAChRs displayed differential sensitivities to perturbations of the interaction between PeIA Pro13 and residue 119 of the β4 subunit. These results highlight the potential significance of species differences in α6β4 nAChR pharmacology that should be taken into consideration when evaluating the activity of candidate human therapeutics in rodent models.
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Affiliation(s)
| | | | - Janet Bobango
- Department of Biomedical and Pharmaceutical Sciences, University of Montana, Missoula, Montana 59812
| | | | | | | | | | - Peta J Harvey
- Institute for Molecular Bioscience, University of Queensland, Brisbane, Queensland 4072, Australia
| | - David J Craik
- Institute for Molecular Bioscience, University of Queensland, Brisbane, Queensland 4072, Australia
| | - J Michael McIntosh
- From the Departments of Biology; Psychiatry, University of Utah, Salt Lake City, Utah 84112; George E. Whalen Veterans Affairs Medical Center, Salt Lake City, Utah 84148.
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37
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Steffensen SC, Shin SI, Nelson AC, Pistorius SS, Williams SB, Woodward TJ, Park HJ, Friend L, Gao M, Gao F, Taylor DH, Foster Olive M, Edwards JG, Sudweeks SN, Buhlman LM, Michael McIntosh J, Wu J. α6 subunit-containing nicotinic receptors mediate low-dose ethanol effects on ventral tegmental area neurons and ethanol reward. Addict Biol 2018; 23:1079-1093. [PMID: 28901722 DOI: 10.1111/adb.12559] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Revised: 08/17/2017] [Accepted: 08/18/2017] [Indexed: 01/02/2023]
Abstract
Dopamine (DA) neuron excitability is regulated by inhibitory GABAergic synaptic transmission and modulated by nicotinic acetylcholine receptors (nAChRs). The aim of this study was to evaluate the role of α6 subunit-containing nAChRs (α6*-nAChRs) in acute ethanol effects on ventral tegmental area (VTA) GABA and DA neurons. α6*-nAChRs were visualized on GABA terminals on VTA GABA neurons, and α6*-nAChR transcripts were expressed in most DA neurons, but only a minority of VTA GABA neurons from GAD67 GFP mice. Low concentrations of ethanol (1-10 mM) enhanced GABAA receptor (GABAA R)-mediated spontaneous and evoked inhibition with blockade by selective α6*-nAChR antagonist α-conotoxins (α-Ctxs) and lowered sensitivity in α6 knock-out (KO) mice. Ethanol suppression of VTA GABA neuron firing rate in wild-type mice in vivo was significantly reduced in α6 KO mice. Ethanol (5-100 mM) had no effect on optically evoked GABAA R-mediated inhibition of DA neurons, and ethanol enhancement of VTA DA neuron firing rate at high concentrations was not affected by α-Ctxs. Ethanol conditioned place preference was reduced in α6 KO mice compared with wild-type controls. Taken together, these studies indicate that relatively low concentrations of ethanol act through α6*-nAChRs on GABA terminals to enhance GABA release onto VTA GABA neurons, in turn to reduce GABA neuron firing, which may lead to VTA DA neuron disinhibition, suggesting a possible mechanism of action of alcohol and nicotine co-abuse.
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Affiliation(s)
- Scott C. Steffensen
- Department of Psychology and Neuroscience; Brigham Young University; Provo UT USA
| | - Samuel I. Shin
- Department of Psychology and Neuroscience; Brigham Young University; Provo UT USA
| | - Ashley C. Nelson
- Department of Psychology and Neuroscience; Brigham Young University; Provo UT USA
| | | | | | - Taylor J. Woodward
- Department of Psychology and Neuroscience; Brigham Young University; Provo UT USA
| | - Hyun Jung Park
- Department of Psychology and Neuroscience; Brigham Young University; Provo UT USA
| | - Lindsey Friend
- Department of Psychology and Neuroscience; Brigham Young University; Provo UT USA
| | - Ming Gao
- Department of Neurobiology, Barrow Neurological Institute; St. Joseph's Hospital and Medical Center; Phoenix AZ USA
| | - Fenfei Gao
- Department of Neurobiology, Barrow Neurological Institute; St. Joseph's Hospital and Medical Center; Phoenix AZ USA
| | | | - M. Foster Olive
- School of Psychology; Arizona State University; Tempe AZ USA
| | - Jeffrey G. Edwards
- Department of Psychology and Neuroscience; Brigham Young University; Provo UT USA
| | - Sterling N. Sudweeks
- Department of Psychology and Neuroscience; Brigham Young University; Provo UT USA
| | - Lori M. Buhlman
- Biomedical Sciences Program; Midwestern University; Glendale AZ USA
| | - J. Michael McIntosh
- Departments of Psychiatry and Biology; University of Utah; Salt Lake City UT USA
| | - Jie Wu
- Department of Neurobiology, Barrow Neurological Institute; St. Joseph's Hospital and Medical Center; Phoenix AZ USA
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38
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Wu X, Tae HS, Huang YH, Adams DJ, Craik DJ, Kaas Q. Stoichiometry dependent inhibition of rat α3β4 nicotinic acetylcholine receptor by the ribbon isomer of α-conotoxin AuIB. Biochem Pharmacol 2018; 155:288-297. [PMID: 30009767 DOI: 10.1016/j.bcp.2018.07.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Accepted: 07/11/2018] [Indexed: 11/17/2022]
Abstract
The ribbon isomer of α-conotoxin AuIB has 10-fold greater potency than the wild-type globular isomer at inhibiting nicotinic acetylcholine receptors (nAChRs) in rat parasympathetic neurons, and unlike its globular isoform, ribbon AuIB only targets a specific stoichiometry of the α3β4 nAChR subtype. Previous electrophysiological recordings of AuIB indicated that ribbon AuIB binds to the α3(+)α3(-) interface within the nAChR extracellular domain, which is displayed by the (α3)3(β4)2 stoichiometry but not by (α3)2(β4)3. This specificity for a particular stoichiometry is remarkable and suggests that ribbon isoforms of α-conotoxins might have great potential in drug design. In this study, we investigated the binding mode and structure-activity relationships of ribbon AuIB using a combination of molecular modeling and electrophysiology recording to determine the features that underpin its selectivity. An alanine scan showed that positions 4 and 9 of ribbon AuIB are the main determinants of the interaction with (α3)3(β4)2 nAChR. Our computational models indicate that the first loop of ribbon AuIB binds in the "aromatic box" of the acetylcholine orthosteric binding site, similar to that of globular AuIB. In contrast, the second loop and the termini of the ribbon isomer have different orientations and interactions in the binding sites to those of the globular isomer. The structure-activity relationships reported herein should be useful to design peptides displaying a ribbon α-conotoxin scaffold for inhibition of nAChR subtypes that have hitherto been difficult to selectively target.
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Affiliation(s)
- Xiaosa Wu
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Han-Shen Tae
- Illawarra Health and Medical Research Institute (IHMRI), The University of Wollongong, Wollongong, New South Wales 2522, Australia
| | - Yen-Hua Huang
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - David J Adams
- Illawarra Health and Medical Research Institute (IHMRI), The University of Wollongong, Wollongong, New South Wales 2522, Australia
| | - David J Craik
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia.
| | - Quentin Kaas
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Queensland 4072, Australia.
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King MD, Long T, Pfalmer DL, Andersen TL, McDougal OM. SPIDR: small-molecule peptide-influenced drug repurposing. BMC Bioinformatics 2018; 19:138. [PMID: 29661129 PMCID: PMC5902895 DOI: 10.1186/s12859-018-2153-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2017] [Accepted: 04/09/2018] [Indexed: 11/20/2022] Open
Abstract
Background Conventional de novo drug design is costly and time consuming, making it accessible to only the best resourced research organizations. An emergent approach to new drug development is drug repurposing, in which compounds that have already gone through some level of clinical testing are examined for efficacy against diseases divergent than their original application. Repurposing of existing drugs circumvents the time and considerable cost of early stages of drug development, and can be accelerated by using software to screen existing chemical databases to identify suitable drug candidates. Results Small-molecule Peptide-Influenced Drug Repurposing (SPIDR) was developed to identify small molecule drugs that target a specific receptor by exploring the conformational binding space of peptide ligands. SPIDR was tested using the potent and selective 16-amino acid peptide α-conotoxin MII ligand and the α3β2-nicotinic acetylcholine receptor (nAChR) isoform. SPIDR incorporates a genetic algorithm-based, heuristic search procedure, which was used to explore the ligand binding domain of the α3β2-nAChR isoform using a library consisting of 640,000 α-conotoxin MII peptide analogs. The peptides that exhibited the highest affinity for α3β2-nAChR were used as models for a small-molecule structure similarity search of the PubChem Compound database. SPIDR incorporates the SimSearcher utility, which generates shape distribution signatures of molecules and employs multi-level K-means clustering to insure fast database queries. SPIDR identified non-peptide drugs with estimated binding affinities nearly double that of the native α-conotoxin MII peptide. Conclusions SPIDR has been generalized and integrated into DockoMatic v 2.1. This software contains an intuitive graphical interface for peptide mutant screening workflow and facilitates mapping, clustering, and searching of local molecular databases, making DockoMatic a valuable tool for researchers in drug design and repurposing. Electronic supplementary material The online version of this article (10.1186/s12859-018-2153-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Matthew D King
- Department of Chemistry and Biochemistry, Boise State University, Boise, USA
| | - Thomas Long
- Department of Computer Science, Boise State University, Boise, USA
| | - Daniel L Pfalmer
- Biomolecular Sciences Ph.D. Program, Boise State University, Boise, USA
| | | | - Owen M McDougal
- Department of Chemistry and Biochemistry, Boise State University, Boise, USA.
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α-Conotoxins to explore the molecular, physiological and pathophysiological functions of neuronal nicotinic acetylcholine receptors. Neurosci Lett 2017; 679:24-34. [PMID: 29199094 DOI: 10.1016/j.neulet.2017.11.063] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 11/28/2017] [Accepted: 11/29/2017] [Indexed: 12/22/2022]
Abstract
The vast diversity of neuronal nicotinic acetylcholine subunits expressed in the central and peripheral nervous systems, as well as in non-neuronal tissues, constitutes a formidable challenge for researchers and clinicians to decipher the role of particular subtypes, including complex subunit associations, in physiological and pathophysiological functions. Many natural products target the nAChRs, but there is no richer source of nicotinic ligands than the venom of predatory gastropods known as cone snails. Indeed, every single species of cone snail was shown to produce at least one type of such α-conotoxins. These tiny peptides (10-25 amino acids), constrained by disulfide bridges, proved to be unvaluable tools to investigate the structure and function of nAChRs, some of them having also therapeutic potential. In this review, we provide a recent update on the pharmacology and subtype specificity of several major α-conotoxins.
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Albillos A, McIntosh JM. Human nicotinic receptors in chromaffin cells: characterization and pharmacology. Pflugers Arch 2017; 470:21-27. [PMID: 29058146 DOI: 10.1007/s00424-017-2073-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Revised: 09/14/2017] [Accepted: 09/19/2017] [Indexed: 02/03/2023]
Abstract
During the last 10 years, we have been working on human chromaffin cells obtained from the adrenal gland of organ donors that suffered encephalic or cardiac death. We first electrophysiologically characterized the nicotinic acetylcholine receptors (nAChRs) activated by acetylcholine, and their contribution to the exocytosis of chromaffin vesicles and release of catecholamines. We have shown that these cells possess an adrenergic phenotype. This phenotype may contribute to an increased expression of α7 nAChRs in these cells, allowing for recording of α7 nAChR currents, something that had previously not been achieved in non-human species. The use of α-conotoxins allowed us to characterize non-α7 nAChR subtypes and, together with molecular biology experiments, conclude that the predominant nAChR subtype in human chromaffin cells is α3β4* (asterisk indicates the posible presence of additional subunits). In addition, there is a minor population of αxβ2 nAChRs. Both α7 and non-α7 nAChR subtypes contribute to the exocytotic process. Exocytosis mediated by nAChRs could be as large in magnitude as that elicited by calcium entry through voltage-dependent calcium channels. Finally, we have also investigated the effect of nAChR-targeted tobacco cessation drugs on catecholamine release in chromaffin cells. We have concluded that at therapeutic concentrations, varenicline alone does not increase the frequency of action potentials evoked by ACh. However, varenicline in the presence of nicotine does increase this frequency, and thus, in the presence of both drugs, the probability of increased catecholamine release in human chromaffin cells is high.
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Affiliation(s)
- Almudena Albillos
- Departamento de Farmacología y Terapéutica, Facultad de Medicina, Universidad Autónoma de Madrid, Calle Arzobispo Morcillo 4, 28029, Madrid, Spain.
| | - J Michael McIntosh
- George E. Whalen Veterans Affairs Medical Center, Salt Lake City, UT, USA.,Department of Biology, University of Utah, Salt Lake City, UT, USA.,Department of Psychiatry, University of Utah, Salt Lake City, UT, USA
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Hone AJ, Servent D, McIntosh JM. α9-containing nicotinic acetylcholine receptors and the modulation of pain. Br J Pharmacol 2017; 175:1915-1927. [PMID: 28662295 DOI: 10.1111/bph.13931] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Revised: 06/09/2017] [Accepted: 06/13/2017] [Indexed: 01/01/2023] Open
Abstract
Neuropathic pain is a complex and debilitating syndrome for which there are few effective pharmacological treatments. Opioid-based medications are initially effective for acute pain, but tolerance to their analgesic effects quickly develops, and long-term use often leads to physical dependence and addiction. Furthermore, neuropathic pain is generally resistant to non-steroidal anti-inflammatory drugs. Other classes of medications including antidepressants, antiepileptics and voltage-gated calcium channel inhibitors are only partially effective in most patients, may be associated with significant side effects and have few disease-modifying effects on the underlying pathology. Medications that act through new mechanisms of action, and particularly ones that have disease-modifying properties, would be highly desirable. In the last decade, a potential new target for the treatment of neuropathic pain has emerged: the α9-containing nicotinic acetylcholine receptor (nAChR). Recent studies indicate that antagonists of α9-containing nAChRs are analgesic in animal models of neuropathic pain. These nerve injury models include chronic constriction injury, partial sciatic nerve ligation, streptozotocin-induced diabetic neuropathy and chemotherapeutic-induced neuropathy. This review details the history and state of the field regarding the role that α9-containing nAChRs may play in neuropathic pain. An alternative hypothesis that α-conotoxins exert their therapeutic effect through blocking N-type calcium channels via activation of GABAB receptors is also reviewed. Understanding how antagonists of α9-containing nAChRs exert their therapeutic effects may ultimately result in the development of medications that not only treat but also prevent the development of neuropathic pain states. LINKED ARTICLES This article is part of a themed section on Nicotinic Acetylcholine Receptors. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v175.11/issuetoc.
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Affiliation(s)
- Arik J Hone
- Department of Biology, University of Utah, Salt Lake City, UT, USA
| | - Denis Servent
- Service d'Ingénierie Moléculaire des Protéines (SIMOPRO), IBITECS, CEA, Université Paris-Saclay, Gif-sur-Yvette, France
| | - J Michael McIntosh
- Department of Biology, University of Utah, Salt Lake City, UT, USA.,George E. Whalen Veterans Affairs Medical Center, Salt Lake City, UT, USA.,Department of Psychiatry, University of Utah, Salt Lake City, UT, USA
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α6β2 subunit containing nicotinic acetylcholine receptors exert opposing actions on rapid dopamine signaling in the nucleus accumbens of rats with high-versus low-response to novelty. Neuropharmacology 2017; 126:281-291. [PMID: 28666811 DOI: 10.1016/j.neuropharm.2017.06.028] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Revised: 06/07/2017] [Accepted: 06/26/2017] [Indexed: 11/22/2022]
Abstract
Determining neurobiological factors that contribute to individual variance in drug addiction vulnerability allows for identification of at-risk populations, use of preventative measures and personalized medicine in the treatment of substance use disorders. Rodents that exhibit high locomotor activity when exploring an inescapable novel environment (high-responder; HR) are more susceptible to the reinforcing effects of many abused compounds, including nicotine, as compared to animals that exhibit low locomotor activity (low-responder; LR). Given that nicotinic acetylcholine receptor (nAChR) modulation of reward-related dopamine signaling at accumbal dopamine terminals is critical for the acquisition of drug self-administration, we hypothesized that nAChR modulation of dopamine release would be predicted by an animal's novelty response. Using voltammetry in the nucleus accumbens core of rats, we found that nicotine produced opposite effects in HR and LR animals on stimulation frequencies that model phasic dopamine release, whereby release magnitude was either augmented or attenuated, respectively. Further, nicotine suppressed dopamine release elected by stimulation frequencies that model tonic release in LR animals, but had no effect in HR animals. The differential effects of nicotine were likely due to desensitization of nAChRs, since the nAChR antagonists mecamylamine (non-selective, 2 μM), dihydro-beta-erythroidine (β2-selective, 500 nM), and α-conotoxin MII [H9A; L15A] (α6-selective, 100 nM) produced effects similar to nicotine. Moreover, dihydro-beta-erythroidine failed to show differential effects in HR and LR rats when applied after α-conotoxin MII [H9A; L15A], suggesting a critical role of α6β2 compared non α6-containing nAChRs in the differential effects observed in these phenotypes. These results delineate a potential mechanism for individual variability in behavioral sensitivity to nicotine.
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44
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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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45
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King MD, Long T, Andersen T, McDougal OM. Genetic Algorithm Managed Peptide Mutant Screening: Optimizing Peptide Ligands for Targeted Receptor Binding. J Chem Inf Model 2016; 56:2378-2387. [PMID: 28024403 DOI: 10.1021/acs.jcim.6b00095] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
This study demonstrates the utility of genetic algorithms to search exceptionally large and otherwise intractable mutant libraries for sequences with optimal binding affinities for target receptors. The Genetic Algorithm Managed Peptide Mutant Screening (GAMPMS) program was used to search an α-conotoxin (α-CTx) MII mutant library of approximately 41 billion possible peptide sequences for those exhibiting the greatest binding affinity for the α3β2-nicotinic acetylcholine receptor (nAChR) isoform. A series of top resulting peptide ligands with high sequence homology was obtained, with each mutant having an estimated ΔGbind approximately double that of the potent native α-CTx MII ligand. A consensus sequence from the top GAMPMS results was subjected to more rigorous binding free energy calculations by molecular dynamics and compared to α-CTx MII and other related variants for binding with α3β2-nAChR. In this study, the efficiency of GAMPMS to substantially reduce the sample population size through evolutionary selection criteria to produce ligands with higher predicted binding affinity is demonstrated.
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Affiliation(s)
- Matthew D King
- Department of Chemistry and Biochemistry and ‡Department of Computer Science, Boise State University , 1910 University Drive, Boise, Idaho 83725, United States
| | - Thomas Long
- Department of Chemistry and Biochemistry and ‡Department of Computer Science, Boise State University , 1910 University Drive, Boise, Idaho 83725, United States
| | - Timothy Andersen
- Department of Chemistry and Biochemistry and ‡Department of Computer Science, Boise State University , 1910 University Drive, Boise, Idaho 83725, United States
| | - Owen M McDougal
- Department of Chemistry and Biochemistry and ‡Department of Computer Science, Boise State University , 1910 University Drive, Boise, Idaho 83725, United States
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Román-González SA, Robles-Gómez EE, Reyes J, Bernáldez J, Cortés-Guzmán F, Martínez-Mayorga K, Lazcano-Pérez F, Licea A, Arreguín-Espinosa R. A 3D structural model of RsXXVIA, an ω-conotoxin. Struct Chem 2016. [DOI: 10.1007/s11224-016-0877-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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47
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Zuo W, Xiao C, Gao M, Hopf FW, Krnjević K, McIntosh JM, Fu R, Wu J, Bekker A, Ye JH. Nicotine regulates activity of lateral habenula neurons via presynaptic and postsynaptic mechanisms. Sci Rep 2016; 6:32937. [PMID: 27596561 PMCID: PMC5011770 DOI: 10.1038/srep32937] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Accepted: 08/12/2016] [Indexed: 11/09/2022] Open
Abstract
There is much interest in brain regions that drive nicotine intake in smokers. Interestingly, both the rewarding and aversive effects of nicotine are probably critical for sustaining nicotine addiction. The medial and lateral habenular (LHb) nuclei play important roles in processing aversion, and recent work has focused on the critical involvement of the LHb in encoding and responding to aversive stimuli. Several neurotransmitter systems are implicated in nicotine’s actions, but very little is known about how nicotinic acetylcholine receptors (nAChRs) regulate LHb activity. Here we report in brain slices that activation of nAChRs depolarizes LHb cells and robustly increases firing, and also potentiates glutamate release in LHb. These effects were blocked by selective antagonists of α6-containing (α6*) nAChRs, and were absent in α6*-nAChR knockout mice. In addition, nicotine activates GABAergic inputs to LHb via α4β2-nAChRs, at lower concentrations but with more rapid desensitization relative to α6*-nAChRs. These results demonstrate the existence of diverse functional nAChR subtypes at presynaptic and postsynaptic sites in LHb, through which nicotine could facilitate or inhibit LHb neuronal activity and thus contribute to nicotine aversion or reward.
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Affiliation(s)
- Wanhong Zuo
- Department of Anesthesiology, Pharmacology and Physiology, Rutgers, The State University of New Jersey, New Jersey Medical School, Newark, New Jersey, USA
| | - Cheng Xiao
- Department of Anesthesiology, Pharmacology and Physiology, Rutgers, The State University of New Jersey, New Jersey Medical School, Newark, New Jersey, USA
| | - Ming Gao
- Divisions of Neurology, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, AZ, USA
| | - F Woodward Hopf
- Department of Neurology, University of California at San Francisco, CA, USA
| | | | - J Michael McIntosh
- George E. Wahlen Veterans Affairs Medical Center and Departments of Psychiatry and Biology, University of Utah, Salt Lake City, UT, USA
| | - Rao Fu
- Department of Anesthesiology, Pharmacology and Physiology, Rutgers, The State University of New Jersey, New Jersey Medical School, Newark, New Jersey, USA
| | - Jie Wu
- Divisions of Neurology, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, Phoenix, AZ, USA
| | - Alex Bekker
- Department of Anesthesiology, Pharmacology and Physiology, Rutgers, The State University of New Jersey, New Jersey Medical School, Newark, New Jersey, USA
| | - Jiang-Hong Ye
- Department of Anesthesiology, Pharmacology and Physiology, Rutgers, The State University of New Jersey, New Jersey Medical School, Newark, New Jersey, USA
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48
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Wu X, Huang Y, Kaas Q, Craik DJ. Cyclisation of Disulfide‐Rich Conotoxins in Drug Design Applications. European J Org Chem 2016. [DOI: 10.1002/ejoc.201600402] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Xiaosa Wu
- Institute for Molecular BioscienceThe University of Queensland306 Carmody Road (Building 80)4072BrisbaneAustralia
| | - Yen‐Hua Huang
- Institute for Molecular BioscienceThe University of Queensland306 Carmody Road (Building 80)4072BrisbaneAustralia
| | - Quentin Kaas
- Institute for Molecular BioscienceThe University of Queensland306 Carmody Road (Building 80)4072BrisbaneAustralia
| | - David J. Craik
- Institute for Molecular BioscienceThe University of Queensland306 Carmody Road (Building 80)4072BrisbaneAustralia
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49
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Nicotinic receptor involvement in regulation of functions of mouse neutrophils from inflammatory site. Immunobiology 2016; 221:761-72. [DOI: 10.1016/j.imbio.2016.01.016] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Accepted: 01/30/2016] [Indexed: 01/08/2023]
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50
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Pang X, Liu L, Ngolab J, Zhao-Shea R, McIntosh JM, Gardner PD, Tapper AR. Habenula cholinergic neurons regulate anxiety during nicotine withdrawal via nicotinic acetylcholine receptors. Neuropharmacology 2016; 107:294-304. [PMID: 27020042 DOI: 10.1016/j.neuropharm.2016.03.039] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Revised: 03/07/2016] [Accepted: 03/23/2016] [Indexed: 11/17/2022]
Abstract
Cholinergic neurons in the medial habenula (MHb) modulate anxiety during nicotine withdrawal although the molecular neuroadaptation(s) within the MHb that induce affective behaviors during nicotine cessation is largely unknown. MHb cholinergic neurons are unique in that they robustly express neuronal nicotinic acetylcholine receptors (nAChRs), although their behavioral role as autoreceptors in these neurons has not been described. To test the hypothesis that nAChR signaling in MHb cholinergic neurons could modulate anxiety, we expressed novel "gain of function" nAChR subunits selectively in MHb cholinergic neurons of adult mice. Mice expressing these mutant nAChRs exhibited increased anxiety-like behavior that was alleviated by blockade with a nAChR antagonist. To test the hypothesis that anxiety induced by nicotine withdrawal may be mediated by increased MHb nicotinic receptor signaling, we infused nAChR subtype selective antagonists into the MHb of nicotine naïve and withdrawn mice. While antagonists had little effect on nicotine naïve mice, blocking α4β2 or α6β2, but not α3β4 nAChRs in the MHb alleviated anxiety in mice undergoing nicotine withdrawal. Consistent with behavioral results, there was increased functional expression of nAChRs containing the α6 subunit in MHb neurons that also expressed the α4 subunit. Together, these data indicate that MHb cholinergic neurons regulate nicotine withdrawal-induced anxiety via increased signaling through nicotinic receptors containing the α6 subunit and point toward nAChRs in MHb cholinergic neurons as molecular targets for smoking cessation therapeutics.
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Affiliation(s)
- Xueyan Pang
- Brudnick Neuropsychiatric Research Institute, Department of Psychiatry, University of Massachusetts Medical School, Worcester, MA 01604, USA; Program in Neuroscience, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Liwang Liu
- Brudnick Neuropsychiatric Research Institute, Department of Psychiatry, University of Massachusetts Medical School, Worcester, MA 01604, USA
| | - Jennifer Ngolab
- Brudnick Neuropsychiatric Research Institute, Department of Psychiatry, University of Massachusetts Medical School, Worcester, MA 01604, USA; Program in Neuroscience, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Rubing Zhao-Shea
- Brudnick Neuropsychiatric Research Institute, Department of Psychiatry, University of Massachusetts Medical School, Worcester, MA 01604, USA
| | - J Michael McIntosh
- George E. Wahlen Veterans Affairs Medical Center, Salt Lake City, UT 84108, USA; Department of Psychiatry, University of Utah, Salt Lake City, UT 84112, USA; Department of Biology, University of Utah, Salt Lake City, UT 84112, USA
| | - Paul D Gardner
- Brudnick Neuropsychiatric Research Institute, Department of Psychiatry, University of Massachusetts Medical School, Worcester, MA 01604, USA; Program in Neuroscience, University of Massachusetts Medical School, Worcester, MA 01655, USA
| | - Andrew R Tapper
- Brudnick Neuropsychiatric Research Institute, Department of Psychiatry, University of Massachusetts Medical School, Worcester, MA 01604, USA; Program in Neuroscience, University of Massachusetts Medical School, Worcester, MA 01655, USA.
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