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Conus regius-Derived Conotoxins: Novel Therapeutic Opportunities from a Marine Organism. Mar Drugs 2022; 20:md20120773. [PMID: 36547920 PMCID: PMC9783627 DOI: 10.3390/md20120773] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 12/03/2022] [Accepted: 12/06/2022] [Indexed: 12/14/2022] Open
Abstract
Conus regius is a marine venomous mollusk of the Conus genus that captures its prey by injecting a rich cocktail of bioactive disulfide bond rich peptides called conotoxins. These peptides selectively target a broad range of ion channels, membrane receptors, transporters, and enzymes, making them valuable pharmacological tools and potential drug leads. C. regius-derived conotoxins are particularly attractive due to their marked potency and selectivity against specific nicotinic acetylcholine receptor subtypes, whose signalling is involved in pain, cognitive disorders, drug addiction, and cancer. However, the species-specific differences in sensitivity and the low stability and bioavailability of these conotoxins limit their clinical development as novel therapeutic agents for these disorders. Here, we give an overview of the main pharmacological features of the C. regius-derived conotoxins described so far, focusing on the molecular mechanisms underlying their potential therapeutic effects. Additionally, we describe adoptable chemical engineering solutions to improve their pharmacological properties for future potential clinical translation.
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A Single Amino Acid Replacement Boosts the Analgesic Activity of α-Conotoxin AuIB through the Inhibition of the GABA BR-Coupled N-Type Calcium Channel. Mar Drugs 2022; 20:md20120750. [PMID: 36547897 PMCID: PMC9781320 DOI: 10.3390/md20120750] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 11/17/2022] [Accepted: 11/22/2022] [Indexed: 11/30/2022] Open
Abstract
α-conotoxin AuIB is the only one of the 4/6 type α-conotoxins (α-CTxs) that inhibits the γ-aminobutyric acid receptor B (GABABR)-coupled N-type calcium channel (CaV2.2). To improve its inhibitory activity, a series of variants were synthesized and evaluated according to the structure-activity relationships of 4/7 type α-CTxs targeting GABABR-coupled CaV2.2. Surprisingly, only the substitution of Pro7 with Arg results in a 2-3-fold increase in the inhibition of GABABR-coupled CaV2.2 (IC50 is 0.74 nM); substitutions of position 9-12 with basic or hydrophobic amino acid and the addition of hydrophobic amino acid Leu or Ile at the second loop to mimic 4/7 type α-CTxs all failed to improve the inhibitory activity of AuIB against GABABR-coupled CaV2.2. Interestingly, the most potent form of AuIB[P7R] has disulfide bridges of "1-4, 2-3" (ribbon), which differs from the "1-3, 2-4" (globular) in the isoforms of wildtype AuIB. In addition, AuIB[P7R](globular) displays potent analgesic activity in the acetic acid writhing model and the partial sciatic nerve injury (PNL) model. Our study demonstrated that 4/6 type α-CTxs, with the disulfide bridge connectivity "1-4, 2-3," are also potent inhibitors for GABABR-coupled CaV2.2, exhibiting potent analgesic activity.
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Scharf P, Rizzetto F, Xavier LF, Farsky SHP. Xenobiotics Delivered by Electronic Nicotine Delivery Systems: Potential Cellular and Molecular Mechanisms on the Pathogenesis of Chronic Kidney Disease. Int J Mol Sci 2022; 23:ijms231810293. [PMID: 36142207 PMCID: PMC9498982 DOI: 10.3390/ijms231810293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 09/01/2022] [Accepted: 09/05/2022] [Indexed: 11/20/2022] Open
Abstract
Chronic kidney disease (CKD) is characterized as sustained damage to the renal parenchyma, leading to impaired renal functions and gradually progressing to end-stage renal disease (ESRD). Diabetes mellitus (DM) and arterial hypertension (AH) are underlying diseases of CKD. Genetic background, lifestyle, and xenobiotic exposures can favor CKD onset and trigger its underlying diseases. Cigarette smoking (CS) is a known modified risk factor for CKD. Compounds from tobacco combustion act through multi-mediated mechanisms that impair renal function. Electronic nicotine delivery systems (ENDS) consumption, such as e-cigarettes and heated tobacco devices, is growing worldwide. ENDS release mainly nicotine, humectants, and flavorings, which generate several byproducts when heated, including volatile organic compounds and ultrafine particles. The toxicity assessment of these products is emerging in human and experimental studies, but data are yet incipient to achieve truthful conclusions about their safety. To build up the knowledge about the effect of currently employed ENDS on the pathogenesis of CKD, cellular and molecular mechanisms of ENDS xenobiotic on DM, AH, and kidney functions were reviewed. Unraveling the toxic mechanisms of action and endpoints of ENDS exposures will contribute to the risk assessment and implementation of proper health and regulatory interventions.
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Marine Origin Ligands of Nicotinic Receptors: Low Molecular Compounds, Peptides and Proteins for Fundamental Research and Practical Applications. Biomolecules 2022; 12:biom12020189. [PMID: 35204690 PMCID: PMC8961598 DOI: 10.3390/biom12020189] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 01/18/2022] [Accepted: 01/19/2022] [Indexed: 02/05/2023] Open
Abstract
The purpose of our review is to briefly show what different compounds of marine origin, from low molecular weight ones to peptides and proteins, offer for understanding the structure and mechanism of action of nicotinic acetylcholine receptors (nAChRs) and for finding novel drugs to combat the diseases where nAChRs may be involved. The importance of the mentioned classes of ligands has changed with time; a protein from the marine snake venom was the first excellent tool to characterize the muscle-type nAChRs from the electric ray, while at present, muscle and α7 receptors are labeled with the radioactive or fluorescent derivatives prepared from α-bungarotoxin isolated from the many-banded krait. The most sophisticated instruments to distinguish muscle from neuronal nAChRs, and especially distinct subtypes within the latter, are α-conotoxins. Such information is crucial for fundamental studies on the nAChR revealing the properties of their orthosteric and allosteric binding sites and mechanisms of the channel opening and closure. Similar data are provided by low-molecular weight compounds of marine origin, but here the main purpose is drug design. In our review we tried to show what has been obtained in the last decade when the listed classes of compounds were used in the nAChR research, applying computer modeling, synthetic analogues and receptor mutants, X-ray and electron-microscopy analyses of complexes with the nAChRs, and their models which are acetylcholine-binding proteins and heterologously-expressed ligand-binding domains.
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Harper AA, Adams DJ. Electrical properties and synaptic transmission in mouse intracardiac ganglion neurons in situ. Physiol Rep 2021; 9:e15056. [PMID: 34582125 PMCID: PMC8477906 DOI: 10.14814/phy2.15056] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Revised: 08/25/2021] [Accepted: 09/08/2021] [Indexed: 12/19/2022] Open
Abstract
The intrinsic cardiac nervous system represents the final site of signal integration for neurotransmission to the myocardium to enable local control of cardiac performance. The electrophysiological characteristics and ganglionic transmission of adult mouse intrinsic cardiac ganglion (ICG) neurons were investigated using a whole-mount ganglion preparation of the excised right atrial ganglion plexus and intracellular microelectrode recording techniques. The passive and active electrical properties of ICG neurons and synaptic transmission including synaptic response strength and efficacy as a function of stimulation frequency were examined. The resting membrane potential and input resistance of ICG neurons were -47.9 ± 4.0 mV and 197.2 ± 81.5 MΩ, respectively. All neurons had somatic action potentials with overshoots of >+15 mV and after-hyperpolarizations having an average of 10 mV amplitude and ~45 ms half duration. Phasic discharge activities were recorded from the majority of neurons studied and several types of excitatory synaptic responses were recorded following inputs from the vagus or interganglionic nerve trunk(s). Most postganglionic neurons (>75%) received a strong, suprathreshold synaptic input and reliably followed high-frequency repetitive nerve stimulation up to at least 50 Hz. Nerve-evoked synaptic transmission was blocked by extracellular Cd2+ , ω-conotoxin CVIE, or α-conotoxin RegIIA, a selective α3-containing nicotinic acetylcholine receptor antagonist. Synaptic transmission and the electrical properties of murine ICG neurons contribute to the pattern of discharge which regulates chronotropic, dromotropic, and inotropic elements of cardiac function.
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Affiliation(s)
- Alexander A. Harper
- Illawarra Health and Medical Research Institute (IHMRI)University of WollongongWollongongNew South WalesAustralia
| | - David J. Adams
- Illawarra Health and Medical Research Institute (IHMRI)University of WollongongWollongongNew South WalesAustralia
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Urriola N, Lang B, Adelstein S. Evaluation of commercially available antibodies and fluorescent conotoxins for the detection of surface ganglionic acetylcholine receptor on the neuroblastoma cell line, IMR-32 by flow cytometry. J Immunol Methods 2021; 498:113124. [PMID: 34425081 DOI: 10.1016/j.jim.2021.113124] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 08/16/2021] [Accepted: 08/17/2021] [Indexed: 11/28/2022]
Abstract
Commercially available antibodies that bind to the human muscle acetylcholine receptor (ACHR) have been validated previously for flow cytometric use (Keefe et al., 2009; Leite et al., 2008; Lozier et al., 2015). Despite a multitude of commercially available antibodies to other nicotinic ACHRs, validation in a wide variety of immunoassay formats is lacking; when studied, a large proportion of these antibodies have been deemed not fit for most research purposes (Garg and Loring, 2017). We have recently described a flow cytometric immunomodulation assay for the diagnosis of Autoimmune Autonomic Ganglionopathy (AAG) (Urriola et al., 2021) that utilises the monoclonal antibody mab35(Urriola et al., 2021) which is specific for ganglionic ACHR (gnACHR) that contain α3 subunits (Vernino et al., 1998). Other fluorescent ligands for α3-gnACHR have not been validated for flow cytometric use. We investigated 7 commercially sourced antibodies and 3 synthetic fluorescent novel conotoxins purported to specifically bind to the extracellular domains of the gnACHR, and compared the results to staining by mab35, using flow cytometry with the neuroblastoma cell line IMR-32. We also evaluated the degree of non-specific binding by depleting the cell membrane of the relevant acetylcholine receptor with a pre-incubation step involving the serum from a patient with Autoimmune Autonomic Ganglionopathy containing pathogenic antibodies to the ganglionic acetylcholine receptor. None of the assessed conotoxins, and only one antibody (mab35) was found to perform adequately in flow cytometric staining of the native ganglionic acetylcholine receptor.
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Affiliation(s)
- Nicolás Urriola
- Department of Clinical Immunology and Allergy, Royal Prince Alfred Hospital, Sydney, Australia; Faculty of Medicine and Health, The University of Sydney, Sydney, New South Wales, Australia.
| | - Bethan Lang
- Nuffield Department of Clinical Neurosciences, University of Oxford, UK
| | - Stephen Adelstein
- Department of Clinical Immunology and Allergy, Royal Prince Alfred Hospital, Sydney, Australia; Faculty of Medicine and Health, The University of Sydney, Sydney, New South Wales, Australia; Central Sydney Immunopathology Laboratory, NSW Health Pathology, Australia
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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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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: 5] [Impact Index Per Article: 1.7] [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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Halder N, Lal G. Cholinergic System and Its Therapeutic Importance in Inflammation and Autoimmunity. Front Immunol 2021; 12:660342. [PMID: 33936095 PMCID: PMC8082108 DOI: 10.3389/fimmu.2021.660342] [Citation(s) in RCA: 66] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 03/26/2021] [Indexed: 12/11/2022] Open
Abstract
Neurological and immunological signals constitute an extensive regulatory network in our body that maintains physiology and homeostasis. The cholinergic system plays a significant role in neuroimmune communication, transmitting information regarding the peripheral immune status to the central nervous system (CNS) and vice versa. The cholinergic system includes the neurotransmitter\ molecule, acetylcholine (ACh), cholinergic receptors (AChRs), choline acetyltransferase (ChAT) enzyme, and acetylcholinesterase (AChE) enzyme. These molecules are involved in regulating immune response and playing a crucial role in maintaining homeostasis. Most innate and adaptive immune cells respond to neuronal inputs by releasing or expressing these molecules on their surfaces. Dysregulation of this neuroimmune communication may lead to several inflammatory and autoimmune diseases. Several agonists, antagonists, and inhibitors have been developed to target the cholinergic system to control inflammation in different tissues. This review discusses how various molecules of the neuronal and non-neuronal cholinergic system (NNCS) interact with the immune cells. What are the agonists and antagonists that alter the cholinergic system, and how are these molecules modulate inflammation and immunity. Understanding the various functions of pharmacological molecules could help in designing better strategies to control inflammation and autoimmunity.
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Affiliation(s)
- Namrita Halder
- Laboratory of Autoimmunity and Tolerance, National Centre for Cell Science, Ganeshkhind, Pune, India
| | - Girdhari Lal
- Laboratory of Autoimmunity and Tolerance, National Centre for Cell Science, Ganeshkhind, Pune, India
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Arunrungvichian K, Chongruchiroj S, Sarasamkan J, Schüürmann G, Brust P, Vajragupta O. In Silico Finding of Key Interaction Mediated α3β4 and α7 Nicotinic Acetylcholine Receptor Ligand Selectivity of Quinuclidine-Triazole Chemotype. Int J Mol Sci 2020; 21:E6189. [PMID: 32867140 PMCID: PMC7504379 DOI: 10.3390/ijms21176189] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 08/20/2020] [Accepted: 08/25/2020] [Indexed: 12/12/2022] Open
Abstract
The selective binding of six (S)-quinuclidine-triazoles and their (R)-enantiomers to nicotinic acetylcholine receptor (nAChR) subtypes α3β4 and α7, respectively, were analyzed by in silico docking to provide the insight into the molecular basis for the observed stereospecific subtype discrimination. Homology modeling followed by molecular docking and molecular dynamics (MD) simulations revealed that unique amino acid residues in the complementary subunits of the nAChR subtypes are involved in subtype-specific selectivity profiles. In the complementary β4-subunit of the α3β4 nAChR binding pocket, non-conserved AspB173 through a salt bridge was found to be the key determinant for the α3β4 selectivity of the quinuclidine-triazole chemotype, explaining the 47-327-fold affinity of the (S)-enantiomers as compared to their (R)-enantiomer counterparts. Regarding the α7 nAChR subtype, the amino acids promoting a however significantly lower preference for the (R)-enantiomers were the conserved TyrA93, TrpA149 and TrpB55 residues. The non-conserved amino acid residue in the complementary subunit of nAChR subtypes appeared to play a significant role for the nAChR subtype-selective binding, particularly at the heteropentameric subtype, whereas the conserved amino acid residues in both principal and complementary subunits are essential for ligand potency and efficacy.
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Affiliation(s)
- Kuntarat Arunrungvichian
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Mahidol University, 447 Sri-Ayutthaya Road, Bangkok 10400, Thailand;
| | - Sumet Chongruchiroj
- Department of Microbiology, Faculty of Pharmacy, Mahidol University, 447 Sri-Ayutthaya Road, Bangkok 10400, Thailand;
| | - Jiradanai Sarasamkan
- Division of Nuclear Medicine, Department of Radiology, Faculty of Medicine, Khon Kaen University, 123 Mittraparp Highway, Khon Kaen 4002, Thailand;
| | - Gerrit Schüürmann
- UFZ Department of Ecological Chemistry, Helmholtz Centre for Environmental Research, Permoserstrasse 15, 04318 Leipzig, Germany;
- Institute of Organic Chemistry, Technical University Bergakademie Freiberg, Leipziger Strasse 29, 09596 Freiberg, Germany
| | - Peter Brust
- Department of Neuroradiopharmaceuticals, Institute of Radiopharmaceutical Cancer Research, Helmholtz-Zentrum Dresden-Rossendorf, Permoserstrasse 15, 04318 Leipzig, Germany;
| | - Opa Vajragupta
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Mahidol University, 447 Sri-Ayutthaya Road, Bangkok 10400, Thailand;
- Office of Research Affairs, Faculty of Pharmaceutical Sciences, Chulalongkorn University, 254 Phayathai Road, Bangkok 10330, Thailand
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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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12
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Eom S, Kim C, Yeom HD, Lee J, Lee S, Baek YB, Na J, Park SI, Kim GY, Lee CM, Lee JH. Molecular Regulation of α3β4 Nicotinic Acetylcholine Receptors by Lupeol in Cardiovascular System. Int J Mol Sci 2020; 21:E4329. [PMID: 32570692 PMCID: PMC7352637 DOI: 10.3390/ijms21124329] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 06/12/2020] [Accepted: 06/15/2020] [Indexed: 11/20/2022] Open
Abstract
Cardiovascular disease (CVD) occurs globally and has a high mortality rate. The highest risk factor for developing CVD is high blood pressure. Currently, natural products are emerging for the treatment of hypertension to avoid the side effects of drugs. Among existing natural products, lupeol is known to be effective against hypertension in animal experiments. However, there exists no study regarding the molecular physiological evidence against the effects of lupeol. Consequently, we investigated the interaction of lupeol with α3β4 nicotinic acetylcholine receptors (nAChRs). In this study, we performed a two-electrode voltage-clamp technique to investigate the effect of lupeol on the α3β4 nicotine acetylcholine receptor using the oocytes of Xenopus laevis. Coapplication of acetylcholine and lupeol inhibited the activity of α3β4 nAChRs in a concentration-dependent, voltage-independent, and reversible manner. We also conducted a mutational experiment to investigate the influence of residues of the α3 and β4 subunits on lupeol binding with nAChRs. Double mutants of α3β4 (I37A/N132A), nAChRs significantly attenuated the inhibitory effects of lupeol compared to wild-type α3β4 nAChRs. A characteristic of α3β4 nAChRs is their effect on transmission in the cardiac sympathetic ganglion. Overall, it is hypothesized that lupeol lowers hypertension by mediating its effects on α3β4 nAChRs. The interaction between lupeol and α3β4 nAChRs provides evidence against its effect on hypertension at the molecular-cell level. In conclusion, the inhibitory effect of lupeol is proposed as a novel therapeutic approach involving the antihypertensive targeting of α3β4 nAChRs. Furthermore, it is proposed that the molecular basis of the interaction between lupeol and α3β4 nAChRs would be helpful in cardiac-pharmacology research and therapeutics.
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Affiliation(s)
- Sanung Eom
- Department of Biotechnology, Chonnam National University, Gwangju 61886, Korea; (S.E.); (C.K.); (H.D.Y.); (J.L.); (S.L.) (J.N.)
| | - Chaelin Kim
- Department of Biotechnology, Chonnam National University, Gwangju 61886, Korea; (S.E.); (C.K.); (H.D.Y.); (J.L.); (S.L.) (J.N.)
| | - Hye Duck Yeom
- Department of Biotechnology, Chonnam National University, Gwangju 61886, Korea; (S.E.); (C.K.); (H.D.Y.); (J.L.); (S.L.) (J.N.)
| | - Jaeeun Lee
- Department of Biotechnology, Chonnam National University, Gwangju 61886, Korea; (S.E.); (C.K.); (H.D.Y.); (J.L.); (S.L.) (J.N.)
| | - Shinhui Lee
- Department of Biotechnology, Chonnam National University, Gwangju 61886, Korea; (S.E.); (C.K.); (H.D.Y.); (J.L.); (S.L.) (J.N.)
| | - Yeong-Bin Baek
- College of Veterinary Medicine, Chonnam National University, Gwangju 61186, Korea; (Y.-B.B.); (S.-I.P.)
| | - Jinseong Na
- Department of Biotechnology, Chonnam National University, Gwangju 61886, Korea; (S.E.); (C.K.); (H.D.Y.); (J.L.); (S.L.) (J.N.)
| | - Sang-Ik Park
- College of Veterinary Medicine, Chonnam National University, Gwangju 61186, Korea; (Y.-B.B.); (S.-I.P.)
| | - Gye-Yeop Kim
- Department of Physical Therapy, Dongshin University, Naju 58245, Korea;
| | - Chang-Min Lee
- College of Veterinary Medicine, Chonnam National University, Gwangju 61186, Korea; (Y.-B.B.); (S.-I.P.)
| | - Jun-Ho Lee
- Department of Biotechnology, Chonnam National University, Gwangju 61886, Korea; (S.E.); (C.K.); (H.D.Y.); (J.L.); (S.L.) (J.N.)
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13
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Jin AH, Muttenthaler M, Dutertre S, Himaya SWA, Kaas Q, Craik DJ, Lewis RJ, Alewood PF. Conotoxins: Chemistry and Biology. Chem Rev 2019; 119:11510-11549. [PMID: 31633928 DOI: 10.1021/acs.chemrev.9b00207] [Citation(s) in RCA: 159] [Impact Index Per Article: 31.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The venom of the marine predatory cone snails (genus Conus) has evolved for prey capture and defense, providing the basis for survival and rapid diversification of the now estimated 750+ species. A typical Conus venom contains hundreds to thousands of bioactive peptides known as conotoxins. These mostly disulfide-rich and well-structured peptides act on a wide range of targets such as ion channels, G protein-coupled receptors, transporters, and enzymes. Conotoxins are of interest to neuroscientists as well as drug developers due to their exquisite potency and selectivity, not just against prey but also mammalian targets, thereby providing a rich source of molecular probes and therapeutic leads. The rise of integrated venomics has accelerated conotoxin discovery with now well over 10,000 conotoxin sequences published. However, their structural and pharmacological characterization lags considerably behind. In this review, we highlight the diversity of new conotoxins uncovered since 2014, their three-dimensional structures and folds, novel chemical approaches to their syntheses, and their value as pharmacological tools to unravel complex biology. Additionally, we discuss challenges and future directions for the field.
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Affiliation(s)
- Ai-Hua Jin
- Institute for Molecular Bioscience , The University of Queensland , Brisbane Queensland 4072 , Australia
| | - Markus Muttenthaler
- Institute for Molecular Bioscience , The University of Queensland , Brisbane Queensland 4072 , Australia.,Institute of Biological Chemistry, Faculty of Chemistry , University of Vienna , 1090 Vienna , Austria
| | - Sebastien Dutertre
- Département des Acides Amines, Peptides et Protéines, Unité Mixte de Recherche 5247, Université Montpellier 2-Centre Nationale de la Recherche Scientifique , Institut des Biomolécules Max Mousseron , Place Eugène Bataillon , 34095 Montpellier Cedex 5 , France
| | - S W A Himaya
- 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
| | - David J Craik
- Institute for Molecular Bioscience , The University of Queensland , Brisbane Queensland 4072 , Australia
| | - Richard J Lewis
- Institute for Molecular Bioscience , The University of Queensland , Brisbane Queensland 4072 , Australia
| | - Paul F Alewood
- Institute for Molecular Bioscience , The University of Queensland , Brisbane Queensland 4072 , Australia
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14
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Manetti D, Garifulina A, Bartolucci G, Bazzicalupi C, Bellucci C, Chiaramonte N, Dei S, Di Cesare Mannelli L, Ghelardini C, Gratteri P, Spirova E, Shelukhina I, Teodori E, Varani K, Tsetlin V, Romanelli MN. New Rigid Nicotine Analogues, Carrying a Norbornane Moiety, Are Potent Agonists of α7 and α3* Nicotinic Receptors. J Med Chem 2019; 62:1887-1901. [PMID: 30681854 DOI: 10.1021/acs.jmedchem.8b01372] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A three-dimensional database search has been applied to design a series of endo- and exo-3-(pyridin-3-yl)bicyclo[2.2.1]heptan-2-amines as nicotinic receptor ligands. The synthesized compounds were tested in radioligand binding assay on rat cortex against [3H]-cytisine and [3H]-methyllycaconitine to measure their affinity for α4β2* and α7* nicotinic receptors. The new derivatives showed some preference for the α4β2* over the α7* subtype, with their affinity being dependent on the endo/exo isomerism and on the methylation degree of the basic nitrogen. The endo primary amines displayed the lowest Ki values on both receptor subtypes. Selected compounds (1a, 2a, 3a, and 6a) were tested on heterologously expressed α4β2, α7, and α3β2 receptors and on SHSY-5Y cells. Compounds 1a and 2a showed α4β2 antagonistic properties while behaved as full agonists on recombinant α7 and on SHSY5Y cells. On the α3β2 subtype, only the chloro derivative 2a showed full agonist activity and submicromolar potency (EC50 = 0.43 μM). The primary amines described here represent new chemotypes for the α7 and α3* receptor subtypes.
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Affiliation(s)
- Dina Manetti
- Department of Neuroscience, Psychology, Drug Research and Child's Health (NEUROFARBA), Section of Pharmaceutical and Nutraceutical Sciences , University of Florence , Via Ugo Schiff 6 , 50019 Sesto Fiorentino , Italy
| | - Alexandra Garifulina
- Department of Molecular Basis of Neurosignaling, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry , Russian Academy of Sciences , Miklukho-Maklaya Street 16/10 , 117997 Moscow , Russia
| | - Gianluca Bartolucci
- Department of Neuroscience, Psychology, Drug Research and Child's Health (NEUROFARBA), Section of Pharmaceutical and Nutraceutical Sciences , University of Florence , Via Ugo Schiff 6 , 50019 Sesto Fiorentino , Italy
| | - Carla Bazzicalupi
- Department of Chemistry "Ugo Schiff" , University of Florence , Via della Lastruccia 3 , 50019 Sesto Fiorentino , Italy
| | - Cristina Bellucci
- Department of Neuroscience, Psychology, Drug Research and Child's Health (NEUROFARBA), Section of Pharmaceutical and Nutraceutical Sciences , University of Florence , Via Ugo Schiff 6 , 50019 Sesto Fiorentino , Italy
| | - Niccolò Chiaramonte
- Department of Neuroscience, Psychology, Drug Research and Child's Health (NEUROFARBA), Section of Pharmaceutical and Nutraceutical Sciences , University of Florence , Via Ugo Schiff 6 , 50019 Sesto Fiorentino , Italy
| | - Silvia Dei
- Department of Neuroscience, Psychology, Drug Research and Child's Health (NEUROFARBA), Section of Pharmaceutical and Nutraceutical Sciences , University of Florence , Via Ugo Schiff 6 , 50019 Sesto Fiorentino , Italy
| | - Lorenzo Di Cesare Mannelli
- Department of NEUROFARBA, Section of Pharmacology and Toxicology , University of Florence , Viale G Pieraccini 6 , 50139 Firenze , Italy
| | - Carla Ghelardini
- Department of NEUROFARBA, Section of Pharmacology and Toxicology , University of Florence , Viale G Pieraccini 6 , 50139 Firenze , Italy
| | - Paola Gratteri
- Department of NEUROFARBA, Laboratory of Molecular Modeling Cheminformatics & QSAR , University of Firenze , Via Ugo Schiff 6 , 50019 Sesto Fiorentino , Italy
| | - Ekaterina Spirova
- Department of Molecular Basis of Neurosignaling, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry , Russian Academy of Sciences , Miklukho-Maklaya Street 16/10 , 117997 Moscow , Russia
| | - Irina Shelukhina
- Department of Molecular Basis of Neurosignaling, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry , Russian Academy of Sciences , Miklukho-Maklaya Street 16/10 , 117997 Moscow , Russia
| | - Elisabetta Teodori
- Department of Neuroscience, Psychology, Drug Research and Child's Health (NEUROFARBA), Section of Pharmaceutical and Nutraceutical Sciences , University of Florence , Via Ugo Schiff 6 , 50019 Sesto Fiorentino , Italy
| | - Katia Varani
- Institute of Pharmacology , University of Ferrara , Via Fossato di Mortara 17-19 , 44100 Ferrara , Italy
| | - Victor Tsetlin
- Department of Molecular Basis of Neurosignaling, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry , Russian Academy of Sciences , Miklukho-Maklaya Street 16/10 , 117997 Moscow , Russia
| | - Maria Novella Romanelli
- Department of Neuroscience, Psychology, Drug Research and Child's Health (NEUROFARBA), Section of Pharmaceutical and Nutraceutical Sciences , University of Florence , Via Ugo Schiff 6 , 50019 Sesto Fiorentino , Italy
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15
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Rationally Designed α-Conotoxin Analogues Maintained Analgesia Activity and Weakened Side Effects. Molecules 2019; 24:molecules24020337. [PMID: 30669328 PMCID: PMC6358911 DOI: 10.3390/molecules24020337] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 01/05/2019] [Accepted: 01/17/2019] [Indexed: 11/16/2022] Open
Abstract
A lack of specificity is restricting the further application of conotoxin from Conus bullatus (BuIA). In this study, an analogue library of BuIA was established and virtual screening was used, which identified high α7 nicotinic acetylcholine receptor (nAChR)-selectivity analogues. The analogues were synthesized and tested for their affinity to functional human α7 nAChR and for the regulation of intracellular calcium ion capacity in neurons. Immunofluorescence, flow cytometry, and patch clamp results showed that the analogues maintained their capacity for calcium regulation. The results of the hot-plate model and paclitaxel-induced peripheral neuropathy model indicated that, when compared with natural BuIA, the analgesia activities of the analogues in different models were maintained. To analyze the adverse effects and toxicity of BuIA and its analogues, the tail suspension test, forced swimming test, and open field test were used. The results showed that the safety and toxicity of the analogues were significantly better than BuIA. The analogues of BuIA with an appropriate and rational mutation showed high selectivity and maintained the regulation of Ca2+ capacity in neurons and activities of analgesia, whereas the analogues demonstrated that the adverse effects of natural α-conotoxins could be reduced.
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16
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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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17
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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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18
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Wonnacott S, Bermudez I, Millar NS, Tzartos SJ. Nicotinic acetylcholine receptors. Br J Pharmacol 2018; 175:1785-1788. [PMID: 29878346 PMCID: PMC5979630 DOI: 10.1111/bph.14209] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
This themed section of the British Journal of Pharmacology is the product of a conference that focussed on nicotinic ACh receptors (nAChRs) that was held on the Greek island of Crete from 7 to 11 May 2017. 'Nicotinic acetylcholine receptors 2017' was the fourth in a series of triennial international meetings that have provided a regular forum for scientists working on all aspects of nAChRs to meet and to discuss new developments. In addition to many of the regular participants, each meeting has also attracted a new group of scientists working in a fast-moving area of research. This themed section comprises both review articles and original research papers on nAChRs. LINKED ARTICLES This article is part of a themed section on Nicotinic Acetylcholine Receptors. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v175.11/issuetoc/.
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Affiliation(s)
- Sue Wonnacott
- Department of Biology & BiochemistryUniversity of BathBathUK
| | - Isabel Bermudez
- Department of Biological and Medical SciencesOxford Brookes UniversityOxfordUK
| | - Neil S Millar
- Department of Neuroscience, Physiology & PharmacologyUniversity College LondonLondonUK
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19
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Cuny H, Yu R, Tae HS, Kompella SN, Adams DJ. α-Conotoxins active at α3-containing nicotinic acetylcholine receptors and their molecular determinants for selective inhibition. Br J Pharmacol 2017; 175:1855-1868. [PMID: 28477355 DOI: 10.1111/bph.13852] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2017] [Revised: 04/13/2017] [Accepted: 04/24/2017] [Indexed: 01/22/2023] Open
Abstract
Neuronal α3-containing nicotinic acetylcholine receptors (nAChRs) in the peripheral nervous system (PNS) and non-neuronal tissues are implicated in a number of severe disease conditions ranging from cancer to cardiovascular diseases and chronic pain. However, despite the physiological characterization of mouse models and cell lines, the precise pathophysiology of nAChRs outside the CNS remains not well understood, in part because there is a lack of subtype-selective antagonists. α-Conotoxins isolated from cone snail venom exhibit characteristic individual selectivity profiles for nAChRs and, therefore, are excellent tools to study the determinants for nAChR-antagonist interactions. Given that human α3β4 subtype selective α-conotoxins are scarce and this is a major nAChR subtype in the PNS, the design of new peptides targeting this nAChR subtype is desirable. Recent studies using α-conotoxins RegIIA and AuIB, in combination with nAChR site-directed mutagenesis and computational modelling, have shed light onto specific nAChR residues, which determine the selectivity of the α-conotoxins for the human α3β2 and α3β4 subtypes. Publications describing the selectivity profile and binding sites of other α-conotoxins confirm that subtype-selective nAChR antagonists often work through common mechanisms by interacting with the same structural components and sites on the receptor. 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)
- Hartmut Cuny
- Illawarra Health and Medical Research Institute (IHMRI), University of Wollongong, Wollongong, NSW, Australia.,Victor Chang Cardiac Research Institute, Developmental and Stem Cell Biology Division, Sydney, NSW, Australia
| | - Rilei Yu
- Key Laboratory of Marine Drugs, Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao, China.,Laboratory for Marine Drugs and Bioproducts of Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Han-Shen Tae
- Illawarra Health and Medical Research Institute (IHMRI), University of Wollongong, Wollongong, NSW, Australia
| | - Shiva N Kompella
- Faculty of Pharmacy, University of Sydney, Sydney, NSW, Australia
| | - David J Adams
- Illawarra Health and Medical Research Institute (IHMRI), University of Wollongong, Wollongong, NSW, Australia
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