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Nicotinic Acetylcholine Receptors and Microglia as Therapeutic and Imaging Targets in Alzheimer's Disease. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27092780. [PMID: 35566132 PMCID: PMC9102429 DOI: 10.3390/molecules27092780] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 04/21/2022] [Accepted: 04/25/2022] [Indexed: 12/12/2022]
Abstract
Amyloid-β (Aβ) accumulation and tauopathy are considered the pathological hallmarks of Alzheimer’s disease (AD), but attenuation in choline signaling, including decreased nicotinic acetylcholine receptors (nAChRs), is evident in the early phase of AD. Currently, there are no drugs that can suppress the progression of AD due to a limited understanding of AD pathophysiology. For this, diagnostic methods that can assess disease progression non-invasively before the onset of AD symptoms are essential, and it would be valuable to incorporate the concept of neurotheranostics, which simultaneously enables diagnosis and treatment. The neuroprotective pathways activated by nAChRs are attractive targets as these receptors may regulate microglial-mediated neuroinflammation. Microglia exhibit both pro- and anti-inflammatory functions that could be modulated to mitigate AD pathogenesis. Currently, single-cell analysis is identifying microglial subpopulations that may have specific functions in different stages of AD pathologies. Thus, the ability to image nAChRs and microglia in AD according to the stage of the disease in the living brain may lead to the development of new diagnostic and therapeutic methods. In this review, we summarize and discuss the recent findings on the nAChRs and microglia, as well as their methods for live imaging in the context of diagnosis, prophylaxis, and therapy for AD.
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2
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Pucci S, Zoli M, Clementi F, Gotti C. α9-Containing Nicotinic Receptors in Cancer. Front Cell Neurosci 2022; 15:805123. [PMID: 35126059 PMCID: PMC8814915 DOI: 10.3389/fncel.2021.805123] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Accepted: 12/29/2021] [Indexed: 12/21/2022] Open
Abstract
Neuronal nicotinic acetylcholine receptors containing the α9 or the α9 and α10 subunits are expressed in various extra-neuronal tissues. Moreover, most cancer cells and tissues highly express α9-containing receptors, and a number of studies have shown that they are powerful regulators of responses that stimulate cancer processes such as proliferation, inhibition of apoptosis, and metastasis. It has also emerged that their modulation is a promising target for drug development. The aim of this review is to summarize recent data showing the involvement of these receptors in controlling the downstream signaling cascades involved in the promotion of cancer.
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Affiliation(s)
- Susanna Pucci
- Institute of Neuroscience, National Research Council (CNR), Milan, Italy
- NeuroMi Milan Center for Neuroscience, University of Milano Bicocca, Milan, Italy
| | - Michele Zoli
- Department of Biomedical, Metabolic and Neural Sciences, Center for Neuroscience and Neurotechnology (CfNN), University of Modena and Reggio Emilia, Modena, Italy
| | - Francesco Clementi
- Institute of Neuroscience, National Research Council (CNR), Milan, Italy
- Department of Medical Biotechnology and Translational Medicine, Università degli Studi di Milano, Milan, Italy
| | - Cecilia Gotti
- Institute of Neuroscience, National Research Council (CNR), Milan, Italy
- NeuroMi Milan Center for Neuroscience, University of Milano Bicocca, Milan, Italy
- *Correspondence: Cecilia Gotti
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3
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Qasem AMA, Zeng Z, Rowan MG, Blagbrough IS. Norditerpenoid alkaloids from Aconitum and Delphinium: structural relevance in medicine, toxicology, and metabolism. Nat Prod Rep 2021; 39:460-473. [PMID: 34636385 DOI: 10.1039/d1np00029b] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Covering: 77 A.D. up to 2020Norditerpenoid alkaloids (NDA), typically N-ethylpiperidine containing C19 or C18 natural product diterpenes, are hexacycles with several contiguous often oxygenated stereocentres. As a function of their structural complexity, they display important pharmacological activities. The processed plants are used as important folk drugs and four NDAs have now been clinically approved. Many metabolism studies on Aconitum alkaloids have been reported as the understanding of their biotransformation in living systems and in cell-free systems is important for the development of these alkaloids as drugs. This Highlight sets out the missing links in NDA biosynthesis, their biological applications, SAR, toxicity, metabolism, and analytical studies.
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Affiliation(s)
- Ashraf M A Qasem
- Department of Pharmacy and Pharmacology, University of Bath, Bath BA2 7AY, UK.
| | - Ziyu Zeng
- Department of Pharmacy and Pharmacology, University of Bath, Bath BA2 7AY, UK.
| | - Michael G Rowan
- Department of Pharmacy and Pharmacology, University of Bath, Bath BA2 7AY, UK.
| | - Ian S Blagbrough
- Department of Pharmacy and Pharmacology, University of Bath, Bath BA2 7AY, UK.
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4
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Abstract
The α7-type nicotinic acetylcholine receptor is one of the most unique and interesting of all the members of the cys-loop superfamily of ligand-gated ion channels. Since it was first identified initially as a binding site for α-bungarotoxin in mammalian brain and later as a functional homomeric receptor with relatively high calcium permeability, it has been pursued as a potential therapeutic target for numerous indications, from Alzheimer disease to asthma. In this review, we discuss the history and state of the art for targeting α7 receptors, beginning with subtype-selective agonists and the basic pharmacophore for the selective activation of α7 receptors. A key feature of α7 receptors is their rapid desensitization by standard "orthosteric" agonist, and we discuss insights into the conformational landscape of α7 receptors that has been gained by the development of ligands binding to allosteric sites. Some of these sites are targeted by positive allosteric modulators that have a wide range of effects on the activation profile of the receptors. Other sites are targeted by direct allosteric agonist or antagonists. We include a perspective on the potential importance of α7 receptors for metabotropic as well as ionotropic signaling. We outline the challenges that exist for future development of drugs to target this important receptor and approaches that may be considered to address those challenges. SIGNIFICANCE STATEMENT: The α7-type nicotinic acetylcholine receptor (nAChR) is acknowledged as a potentially important therapeutic target with functional properties associated with both ionotropic and metabotropic signaling. The functional properties of α7 nAChR can be regulated in diverse ways with the variety of orthosteric and allosteric ligands described in this review.
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Affiliation(s)
- Roger L Papke
- Departments of Pharmacology and Therapeutics (R.L.P) and Chemistry (N.A.H.), University of Florida, Gainesville, FL
| | - Nicole A Horenstein
- Departments of Pharmacology and Therapeutics (R.L.P) and Chemistry (N.A.H.), University of Florida, Gainesville, FL
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Shimizu Y, Shimizu T, Zou S, Ono H, Hata Y, Yamamoto M, Aratake T, Shimizu S, Higashi Y, Karashima T, Saito M. Stimulation of brain α7-nicotinic acetylcholine receptors suppresses the rat micturition through brain GABAergic receptors. Biochem Biophys Res Commun 2021; 548:84-90. [PMID: 33636639 DOI: 10.1016/j.bbrc.2021.02.051] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 02/12/2021] [Indexed: 12/15/2022]
Abstract
Brain nicotinic acetylcholine receptors (nAChRs) reportedly suppress the micturition, but the mechanisms responsible for this suppression remain unclear. We previously reported that intracerebroventricularly administered (±)-epibatidine (non-selective nAChR agonist) activated the sympatho-adrenomedullary system, which can affect the micturition. Therefore, we investigated (1) whether intracerebroventricularly administered (±)-epibatidine-induced effects on the micturition were dependent on the sympatho-adrenomedullary system, and (2) brain nAChR subtypes involved in the (±)-epibatidine-induced effects in urethane-anesthetized male Wistar rats. Plasma noradrenaline and adrenaline (catecholamines) were measured just before and 5 min after (±)-epibatidine administration. Evaluation of urodynamic parameters, intercontraction intervals (ICI) and maximal voiding pressure (MVP) by cystometry was started 1 h before (±)-epibatidine administration or intracerebroventricular pretreatment with other drugs and continued 1 h after (±)-epibatidine administration. Intracerebroventricularly administered (±)-epibatidine elevated plasma catecholamines and prolonged ICI without affecting MVP, and these changes were suppressed by intracerebroventricularly pretreated mecamylamine (non-selective nAChR antagonist). Acute bilateral adrenalectomy abolished the (±)-epibatidine-induced elevation of plasma catecholamines, but had no effect on the (±)-epibatidine-induced ICI prolongation. The latter was suppressed by intracerebroventricularly pretreated methyllycaconitine (selective α7-nAChR antagonist), SR95531 (GABAA antagonist), and SCH50911 (GABAB antagonist), but not by dihydro-β-erythroidine (selective α4β2-nAChR antagonist). Intracerebroventricularly administered PHA568487 (selective α7-nAChR agonist) prolonged ICI without affecting MVP, similar to (±)-epibatidine. These results suggest that stimulation of brain α7-nAChRs suppresses the rat micturition through brain GABAA/GABAB receptors, independently of the sympatho-adrenomedullary outflow modulation.
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Affiliation(s)
- Yohei Shimizu
- Department of Pharmacology, Kochi Medical School, Kochi University, Nankoku, Kochi, 783-8505, Japan; Center for Innovative and Translational Medicine, Kochi Medical School, Kochi University, Nankoku, Kochi, 783-8505, Japan
| | - Takahiro Shimizu
- Department of Pharmacology, Kochi Medical School, Kochi University, Nankoku, Kochi, 783-8505, Japan.
| | - Suo Zou
- Department of Pharmacology, Kochi Medical School, Kochi University, Nankoku, Kochi, 783-8505, Japan
| | - Hideaki Ono
- Department of Pharmacology, Kochi Medical School, Kochi University, Nankoku, Kochi, 783-8505, Japan; Center for Innovative and Translational Medicine, Kochi Medical School, Kochi University, Nankoku, Kochi, 783-8505, Japan
| | - Yurika Hata
- Department of Pharmacology, Kochi Medical School, Kochi University, Nankoku, Kochi, 783-8505, Japan; Center for Innovative and Translational Medicine, Kochi Medical School, Kochi University, Nankoku, Kochi, 783-8505, Japan
| | - Masaki Yamamoto
- Department of Pharmacology, Kochi Medical School, Kochi University, Nankoku, Kochi, 783-8505, Japan
| | - Takaaki Aratake
- Department of Pharmacology, Kochi Medical School, Kochi University, Nankoku, Kochi, 783-8505, Japan; Japan Society for the Promotion of Science, Japan
| | - Shogo Shimizu
- Department of Pharmacology, Kochi Medical School, Kochi University, Nankoku, Kochi, 783-8505, Japan
| | - Youichirou Higashi
- Department of Pharmacology, Kochi Medical School, Kochi University, Nankoku, Kochi, 783-8505, Japan
| | - Takashi Karashima
- Department of Urology, Kochi Medical School, Kochi University, Nankoku, Kochi, 783-8505, Japan
| | - Motoaki Saito
- Department of Pharmacology, Kochi Medical School, Kochi University, Nankoku, Kochi, 783-8505, Japan
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6
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Zeng Z, Kociok‐Köhn G, Woodman TJ, Rowan MG, Blagbrough IS. Structural Studies of Norditerpenoid Alkaloids: Conformation Analysis in Crystal and in Solution States. European J Org Chem 2021. [DOI: 10.1002/ejoc.202100179] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Ziyu Zeng
- Department of Pharmacy and Pharmacology University of Bath Bath BA2 7AY UK
| | - Gabriele Kociok‐Köhn
- Material and Chemical Characterisation Facility University of Bath Bath BA2 7AY UK
| | - Timothy J. Woodman
- Department of Pharmacy and Pharmacology University of Bath Bath BA2 7AY UK
| | - Michael G. Rowan
- Department of Pharmacy and Pharmacology University of Bath Bath BA2 7AY UK
| | - Ian S. Blagbrough
- Department of Pharmacy and Pharmacology University of Bath Bath BA2 7AY UK
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7
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Le Mauff A, Chouikh H, Cartereau A, Charvet CL, Neveu C, Rispe C, Plantard O, Taillebois E, Thany SH. Nicotinic acetylcholine receptors in the synganglion of the tick Ixodes ricinus: Functional characterization using membrane microtransplantation. INTERNATIONAL JOURNAL FOR PARASITOLOGY-DRUGS AND DRUG RESISTANCE 2020; 14:144-151. [PMID: 33120248 PMCID: PMC7591337 DOI: 10.1016/j.ijpddr.2020.10.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 10/04/2020] [Accepted: 10/07/2020] [Indexed: 11/28/2022]
Abstract
Nicotinic acetylcholine receptors are an important class of excitatory receptors in the central nervous system of arthropods. In the ticks Ixodes ricinus, the functional and pharmacological properties of nicotinic receptors located in their neurons are still unknown. The objective of this study was to characterize the pharmacological properties of tick nicotinic receptors using membrane microtransplantation in Xenopus laevis oocytes and two-electrodes voltage clamp method. The membranes microtransplanted were extracted from the tick synganglion. We found that oocytes microtransplanted with tick synganglion membranes expressed nicotinic acetylcholine receptor subtypes which were activated by acetylcholine (1 mM) and nicotine (1 mM). Currents induced by pressure application of acetylcholine and nicotine were diminished by 10 nM α-bungarotoxin and methyllycaconitine, suggesting that they expressed two subtypes of nicotinic receptors, α-bungarotoxin-sensitive and -insensitive, respectively. In addition, we found that nicotine receptors expressed in the synganglion membranes were poorly sensitive to the neonicotinoid insecticides clothianidin (CLT), imidacloprid (IMI), acetamiprid (ACE) and thiamethoxam (TMX), in agreement with their lack of activity as acaricides. Interestingly, current amplitudes were strongly potentialized in the presence of 1 μM PNU-120596. CLT was more active as an agonist than IMI, TMX and ACE. Finally, we demonstrated that microtransplantation of purified membrane from the tick synganglion can be a valuable tool for the development and screening of compounds targeting tick nicotinic acetylcholine receptor subtypes.
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Affiliation(s)
- Anaïs Le Mauff
- LBLGC USC INRAE 1328, Université d'Orléans, 1 rue de Chartres, 45067, Orléans, France
| | - Hamza Chouikh
- LBLGC USC INRAE 1328, Université d'Orléans, 1 rue de Chartres, 45067, Orléans, France
| | - Alison Cartereau
- LBLGC USC INRAE 1328, Université d'Orléans, 1 rue de Chartres, 45067, Orléans, France
| | | | | | | | | | - Emiliane Taillebois
- LBLGC USC INRAE 1328, Université d'Orléans, 1 rue de Chartres, 45067, Orléans, France
| | - Steeve H Thany
- LBLGC USC INRAE 1328, Université d'Orléans, 1 rue de Chartres, 45067, Orléans, France.
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8
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Cartereau A, Taillebois E, Selvam B, Martin C, Graton J, Le Questel JY, Thany SH. Cloning and Expression of Cockroach α7 Nicotinic Acetylcholine Receptor Subunit. Front Physiol 2020; 11:418. [PMID: 32457646 PMCID: PMC7221154 DOI: 10.3389/fphys.2020.00418] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Accepted: 04/07/2020] [Indexed: 11/13/2022] Open
Abstract
Understanding insect nicotinic acetylcholine receptor (nAChR) subtypes is of major interest because they are the main target of several insecticides. In this study, we have cloned a cockroach Pameα7 subunit that encodes a 518 amino acid protein with futures typical of nAChR subunit, and sequence homology to α7 subunit. Pameα7 is differently expressed in the cockroach nervous system, in particular in the antennal lobes, optical lobes and the mushroom bodies where specific expression was found in the non-compact Kenyon cells. In addition, we found that cockroach Pameα7 subunits expressed in Xenopus laevis oocytes can assemble to form homomeric receptors. Electrophysiological recordings using the two-electrode voltage clamp method demonstrated that nicotine induced an I max current of -92 ± 27 nA at 1 mM. Despite that currents are low with the endogenous ligand, ACh, this study provides information on the first expression of cockroach α7 homomeric receptor.
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Affiliation(s)
- Alison Cartereau
- LBLGC, UPRES EA 1207-USC INRA 1328, Université d’Orléans, Orléans, France
| | | | - Balaji Selvam
- Roger Adams Laboratory, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - Carine Martin
- LBLGC, UPRES EA 1207-USC INRA 1328, Université d’Orléans, Orléans, France
| | - Jérôme Graton
- CEISAM-UMR CNRS 6230, Faculté des Sciences et des Techniques, Université de Nantes, Nantes, France
| | - Jean-Yves Le Questel
- CEISAM-UMR CNRS 6230, Faculté des Sciences et des Techniques, Université de Nantes, Nantes, France
| | - Steeve H. Thany
- LBLGC, UPRES EA 1207-USC INRA 1328, Université d’Orléans, Orléans, France
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9
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Gao H, Wang S, Qiang B, Wang S, Zhang H. Radioiodinated 9-fluorenone derivatives for imaging α7-nicotinic acetylcholine receptors. MEDCHEMCOMM 2019; 10:2102-2110. [PMID: 32904124 DOI: 10.1039/c9md00415g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Accepted: 10/14/2019] [Indexed: 11/21/2022]
Abstract
A series of 9H-fluoren-9-one substituents were synthesized and evaluated for imaging cerebral α7-nAChRs. Meta-iodine substituted 9-fluorenone 5 with high binding affinity (K i = 9.3 nM) and selectivity was radiolabeled with 125I. Fully in vitro and in vivo studies of [125I]5 have been performed. [125I]5 exhibited well brain uptake with a peak concentration of 7.5 ± 0.9% ID/g in mice brains. Moreover, ex vivo autoradiography studies and micro single-photon emission computed tomography (micro-SPECT/CT) dynamic imaging in mice confirmed its in vivo imaging properties. Besides, molecular docking and MD studies were also performed to interpret the binding mechanisms of the two series of ligands towards α7-nAChRs. To conclude, the meta-iodine substituted 9-fluorenone [125I]5 could be a promising tracer for imaging α7-nAChRs.
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Affiliation(s)
- Hang Gao
- Key Laboratory of Radiopharmaceuticals of Ministry of Education , College of Chemistry , Beijing Normal University , Beijing 100875 , China .
| | - Shuxia Wang
- Key Laboratory of Radiopharmaceuticals of Ministry of Education , College of Chemistry , Beijing Normal University , Beijing 100875 , China .
| | - Bingchao Qiang
- Key Laboratory of Radiopharmaceuticals of Ministry of Education , College of Chemistry , Beijing Normal University , Beijing 100875 , China .
| | - Sixuan Wang
- Key Laboratory of Radiopharmaceuticals of Ministry of Education , College of Chemistry , Beijing Normal University , Beijing 100875 , China .
| | - Huabei Zhang
- Key Laboratory of Radiopharmaceuticals of Ministry of Education , College of Chemistry , Beijing Normal University , Beijing 100875 , China .
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10
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Telles-Longui M, Mourelle D, Schöwe NM, Cipolli GC, Malerba HN, Buck HS, Viel TA. α7 nicotinic ACh receptors are necessary for memory recovery and neuroprotection promoted by attention training in amyloid-β-infused mice. Br J Pharmacol 2019; 176:3193-3205. [PMID: 31144293 DOI: 10.1111/bph.14744] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Revised: 05/04/2019] [Accepted: 05/10/2019] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND AND PURPOSE Attention training reverses the neurodegeneration and memory loss promoted by infusion of amyloid-β (Aβ) peptide in rats and increases the density of α7 nicotinic ACh receptors (α7nAChRs) in brain areas related to memory. Hence, we aimed to assess the role of α7nAChRs in the memory recovery promoted by attention training. EXPERIMENTAL APPROACH C57Bl/6 mice were chronically infused with Aβ, Aβ plus the α7 antagonist methyllycaconitine (MLA), or MLA alone. Control animals were infused with vehicle. Animals were subjected weekly to the active avoidance shuttle box for 4 weeks (attention training). The brain and serum were collected for biochemical and histological analysis. KEY RESULTS Aβ caused cognitive impairment, which was reversed by the weekly training, whereas Aβ + MLA also promoted memory loss but with no reversal with weekly training. MLA alone also promoted memory loss but with only partial reversal with the training. Animals infused with Aβ alone showed senile plaques in hippocampus, no change in BDNF levels in cortex, hippocampus, and serum, but increased AChE activity in cortex and hippocampus. Co-treatment with MLA increased AChE activity and senile plaque deposition in hippocampus as well as reducing BDNF in hippocampus and serum, suggesting a lack of α7nAChR function leads to a loss of neuroprotection mechanisms. CONCLUSIONS AND IMPLICATIONS The α7nAChR has a determinant role in memory recovery and brain resilience in the presence of neurodegeneration promoted by Aβ peptide. These data support further studies concerning these receptors as pharmacological targets for future therapies.
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Affiliation(s)
- Milena Telles-Longui
- Graduate Course on Pharmacology, Institute of Biomedical Sciences, Universidade de São Paulo, São Paulo, Brazil
| | - Danilo Mourelle
- Graduate Course on Pharmacology, Institute of Biomedical Sciences, Universidade de São Paulo, São Paulo, Brazil
| | - Natalia Mendes Schöwe
- Graduate Course on Pharmacology, Institute of Biomedical Sciences, Universidade de São Paulo, São Paulo, Brazil.,Research Group on Neuropharmacology of Aging, São Paulo, Brazil
| | | | - Helena Nascimento Malerba
- Graduate Course on Pharmacology, Institute of Biomedical Sciences, Universidade de São Paulo, São Paulo, Brazil.,Research Group on Neuropharmacology of Aging, São Paulo, Brazil
| | - Hudson Sousa Buck
- Department of Physiological Sciences, Santa Casa de São Paulo School of Medical Sciences, São Paulo, Brazil.,Research Group on Neuropharmacology of Aging, São Paulo, Brazil
| | - Tania Araujo Viel
- Graduate Course on Pharmacology, Institute of Biomedical Sciences, Universidade de São Paulo, São Paulo, Brazil.,School of Arts, Sciences and Humanities, Universidade de São Paulo, São Paulo, Brazil
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11
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van Goethem NP, Paes D, Puzzo D, Fedele E, Rebosio C, Gulisano W, Palmeri A, Wennogle LP, Peng Y, Bertrand D, Prickaerts J. Antagonizing α7 nicotinic receptors with methyllycaconitine (MLA) potentiates receptor activity and memory acquisition. Cell Signal 2019; 62:109338. [PMID: 31176021 DOI: 10.1016/j.cellsig.2019.06.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Revised: 06/03/2019] [Accepted: 06/03/2019] [Indexed: 12/11/2022]
Abstract
α7 nicotinic acetylcholine receptors (α7nAChRs) have been targeted to improve cognition in different neurological and psychiatric disorders. Nevertheless, no α7nAChR activating ligand has been clinically approved. Here, we investigated the effects of antagonizing α7nAChRs using the selective antagonist methyllycaconitine (MLA) on receptor activity in vitro and cognitive functioning in vivo. Picomolar concentrations of MLA significantly potentiated receptor responses in electrophysiological experiments mimicking the in vivo situation. Furthermore, microdialysis studies showed that MLA administration substantially increased hippocampal glutamate efflux which is related to memory processes. Accordingly, pre-tetanus administration of low MLA concentrations produced longer lasting potentiation (long-term potentiation, LTP) in studies examining hippocampal plasticity. Moreover, low doses of MLA improved acquisition, but not consolidation memory processes in rats. While the focus to enhance cognition by modulating α7nAChRs lies on agonists and positive modulators, antagonists at low doses should provide a novel approach to improve cognition in neurological and psychiatric disorders.
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Affiliation(s)
- Nick P van Goethem
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, 6200, MD, Maastricht, The Netherlands
| | - Dean Paes
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, 6200, MD, Maastricht, The Netherlands
| | - Daniela Puzzo
- Department of Biomedical and Biotechnological Sciences, Section of Physiology, University of Catania, 95124 Catania, Italy
| | - Ernesto Fedele
- Department of Pharmacy, Section of Pharmacology and Toxicology, School of Medical and Pharmaceutical Sciences, Centre of Excellence for Biomedical Research, University of Genoa, 16148 Genoa, Italy; IRCCS Polyclinic Hospital San Martino, 16132 Genoa, Italy
| | - Claudia Rebosio
- Department of Pharmacy, Section of Pharmacology and Toxicology, School of Medical and Pharmaceutical Sciences, Centre of Excellence for Biomedical Research, University of Genoa, 16148 Genoa, Italy
| | - Walter Gulisano
- Department of Biomedical and Biotechnological Sciences, Section of Physiology, University of Catania, 95124 Catania, Italy
| | - Agostino Palmeri
- Department of Biomedical and Biotechnological Sciences, Section of Physiology, University of Catania, 95124 Catania, Italy
| | | | - Youyi Peng
- Intra-Cellular Therapies, Inc., New York 10016, United States
| | - Daniel Bertrand
- HiQScreen Sàrl, 6, rte de Compois, 1222, Vésenaz, Geneva, Switzerland
| | - Jos Prickaerts
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, 6200, MD, Maastricht, The Netherlands.
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12
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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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13
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Garton DR, Ross SG, Maldonado-Hernández R, Quick M, Lasalde-Dominicci JA, Lizardi-Ortiz JE. Amphetamine enantiomers inhibit homomeric α7 nicotinic receptor through a competitive mechanism and within the intoxication levels in humans. Neuropharmacology 2018; 144:172-183. [PMID: 30359640 DOI: 10.1016/j.neuropharm.2018.10.032] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 10/10/2018] [Accepted: 10/21/2018] [Indexed: 11/28/2022]
Abstract
Amphetamine-type stimulants (ATS) are the second most consumed illicit drug worldwide and lack good treatments for associated substance use disorders, lagging behind other addictive drugs. For this reason, a deeper understanding of the pharmacodynamics of ATS is required. The present study seeks to determine amphetamine (AMPH) enantiomers' effects on the homomeric α7 nicotinic acetylcholine receptor (α7 nAChR). Here we have shown that AMPH enantiomers bind to the α7 nAChR and competitively inhibit acetylcholine responses. Our in silico docking analysis suggests that AMPH binds close to the β7 strand of the B-loop of a chimera comprising of the human α7 nAChR and the acetylcholine binding protein from Lymnaea stagnalis. This may inhibit the required movement of the C-loop for channel opening, due to steric hindrance, providing a structural mechanism for its antagonist effect. Finally, we have shown that, in α7 nAChR full knockout mice, the behavioral response to D-AMPH is attenuated, providing direct evidence for the role of α7 nAChRs on the physiological response to D-AMPH. Importantly, D-AMPH exerts these effects at concentrations predicted to be pharmacologically relevant for chronic methamphetamine users and during binges. In conclusion, our data present new findings that implicate the α7 nAChR on the pharmacodynamics of ATS, which may be important for behavioral responses to these drugs, indicating a potential role for α7 nAChRs in ATS substance-use disorders.
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Affiliation(s)
- Daniel R Garton
- Columbia College of Columbia University, New York, NY, 10027, USA
| | - Sharmaine G Ross
- Department of Biobehavioral Sciences, Teachers College Columbia University, New York, NY, 10027, USA
| | | | - Matthias Quick
- Department of Psychiatry, Molecular Therapeutics Division, Columbia University Medical Center, New York, NY, 10032, USA
| | - José A Lasalde-Dominicci
- Departments of Biology and Chemistry, University of Puerto Rico, Río Piedras Campus, San Juan, PR, 00931, USA; Molecular Sciences Research Center, University of Puerto Rico, San Juan, PR, 00927, USA
| | - José E Lizardi-Ortiz
- Molecular Sciences Research Center, University of Puerto Rico, San Juan, PR, 00927, USA; Departments of Neurology and Psychiatry, Columbia University Medical Center, New York, NY, 10032, USA.
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14
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Nichols AL, Noridomi K, Hughes CR, Jalali-Yazdi F, Eaton JB, Lai LH, Advani G, Lukas RJ, Lester HA, Chen L, Roberts RW. α1-FANGs: Protein Ligands Selective for the α-Bungarotoxin Site of the α1-Nicotinic Acetylcholine Receptor. ACS Chem Biol 2018; 13:2568-2576. [PMID: 30059207 DOI: 10.1021/acschembio.8b00513] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Nicotinic acetylcholine receptors (nAChRs) are pentameric ligand-gated ion channels that play a central role in neuronal and neuromuscular signal transduction. Here, we have developed FANG ligands, fibronectin antibody-mimetic nicotinic acetylcholine receptor-generated ligands, using mRNA display. We generated a 1 trillion-member primary e10FnIII library to target a stabilized α1 nicotinic subunit (α211). This library yielded 270000 independent potential protein binding ligands. The lead sequence, α1-FANG1, represented 25% of all library sequences, showed the highest-affinity binding, and competed with α-bungarotoxin (α-Btx). To improve this clone, a new library based on α1-FANG1 was subjected to heat, protease, binding, off-rate selective pressures, and point mutations. This resulted in α1-FANG2 and α1-FANG3. These proteins bind α211 with KD values of 3.5 nM and 670 pM, respectively, compete with α-Btx, and show improved subunit specificity. α1-FANG3 is thermostable ( Tm = 62 °C) with a 6 kcal/mol improvement in folding free energy compared with that of the parent α1-FANG1. α1-FANG3 competes directly with the α-Btx binding site of intact neuromuscular heteropentamers [(α1)2β1γδ] in mammalian culture-derived cellular membranes and in Xenopus laevis oocytes expressing these nAChRs. This work demonstrates that mRNA display against a monomeric ecto-domain of a pentamer has the capability to select ligands that bind that subunit in both a monomeric and a pentameric context. Overall, our work provides a route to creating a new family of stable, well-behaved proteins that specifically target this important receptor family.
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Affiliation(s)
- Aaron L. Nichols
- Department of Chemistry, University of Southern California, Los Angeles, California 90089-1062, United States
| | - Kaori Noridomi
- Molecular and Computational Biology, Department of Biology, University of Southern California, Los Angeles, California 90089-0371, United States
| | - Christopher R. Hughes
- Mork Family Department of Chemical Engineering and Material Sciences, University of Southern California, Los Angeles, California 90089-1211, United States
| | - Farzad Jalali-Yazdi
- Mork Family Department of Chemical Engineering and Material Sciences, University of Southern California, Los Angeles, California 90089-1211, United States
| | - J. Brek Eaton
- Barrow Neurological Institute, St. Joseph’s Hospital and Medical Center, University of Arizona, Phoenix, Arizona 85013-4409, United States
| | - Lan Huong Lai
- Department of Chemistry, University of Southern California, Los Angeles, California 90089-1062, United States
| | - Gaurav Advani
- Mork Family Department of Chemical Engineering and Material Sciences, University of Southern California, Los Angeles, California 90089-1211, United States
| | - Ronald J. Lukas
- Barrow Neurological Institute, St. Joseph’s Hospital and Medical Center, University of Arizona, Phoenix, Arizona 85013-4409, United States
| | - Henry A. Lester
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, California 91125-0001, United States
| | - Lin Chen
- Department of Chemistry, University of Southern California, Los Angeles, California 90089-1062, United States
- Molecular and Computational Biology, Department of Biology, University of Southern California, Los Angeles, California 90089-0371, United States
- Norris Cancer Center, University of Southern California, Los Angeles, California 90033, United States
| | - Richard W. Roberts
- Department of Chemistry, University of Southern California, Los Angeles, California 90089-1062, United States
- Molecular and Computational Biology, Department of Biology, University of Southern California, Los Angeles, California 90089-0371, United States
- Mork Family Department of Chemical Engineering and Material Sciences, University of Southern California, Los Angeles, California 90089-1211, United States
- Norris Cancer Center, University of Southern California, Los Angeles, California 90033, United States
- Department of Biomedical Engineering, University of Southern California, Los Angeles, California 90089-1111, United States
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15
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Higashi Y, Shimizu T, Yamamoto M, Tanaka K, Yawata T, Shimizu S, Zou S, Ueba T, Yuri K, Saito M. Stimulation of brain nicotinic acetylcholine receptors activates adrenomedullary outflow via brain inducible NO synthase-mediated S-nitrosylation. Br J Pharmacol 2018; 175:3758-3772. [PMID: 30007012 DOI: 10.1111/bph.14445] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Revised: 05/26/2018] [Accepted: 07/04/2018] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND AND PURPOSE We have demonstrated that i.c.v.-administered (±)-epibatidine, a nicotinic ACh receptor (nAChR) agonist, induced secretion of noradrenaline and adrenaline (catecholamines) from the rat adrenal medulla with dihydro-β-erythroidin (an α4β2 nAChR antagonist)-sensitive brain mechanisms. Here, we examined central mechanisms for the (±)-epibatidine-induced responses, focusing on brain NOS and NO-mediated mechanisms, soluble GC (sGC) and protein S-nitrosylation (a posttranslational modification of protein cysteine thiol groups), in urethane-anaesthetized (1.0 g·kg-1 , i.p.) male Wistar rats. EXPERIMENTAL APPROACH (±)-Epibatidine was i.c.v. treated after i.c.v. pretreatment with each inhibitor described below. Then, plasma catecholamines were measured electrochemically after HPLC. Immunoreactivity of S-nitrosylated cysteine (SNO-Cys) in α4 nAChR subunit (α4)-positive spinally projecting neurones in the rat hypothalamic paraventricular nucleus (PVN, a regulatory centre of adrenomedullary outflow) after i.c.v. (±)-epibatidine administration was also investigated. KEY RESULTS (±)-Epibatidine-induced elevation of plasma catecholamines was significantly attenuated by L-NAME (non-selective NOS inhibitor), carboxy-PTIO (NO scavenger), BYK191023 [selective inducible NOS (iNOS) inhibitor] and dithiothreitol (thiol-reducing reagent), but not by 3-bromo-7-nitroindazole (selective neuronal NOS inhibitor) or ODQ (sGC inhibitor). (±)-Epibatidine increased the number of spinally projecting PVN neurones with α4- and SNO-Cys-immunoreactivities, and this increment was reduced by BYK191023. CONCLUSIONS AND IMPLICATIONS Stimulation of brain nAChRs can induce elevation of plasma catecholamines through brain iNOS-derived NO-mediated protein S-nitrosylation in rats. Therefore, brain nAChRs (at least α4β2 subtype) and NO might be useful targets for alleviation of catecholamines overflow induced by smoking.
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Affiliation(s)
- Youichirou Higashi
- Department of Pharmacology, Kochi Medical School, Kochi University, Nankoku, Kochi, Japan
| | - Takahiro Shimizu
- Department of Pharmacology, Kochi Medical School, Kochi University, Nankoku, Kochi, Japan
| | - Masaki Yamamoto
- Department of Pharmacology, Kochi Medical School, Kochi University, Nankoku, Kochi, Japan
| | - Kenjiro Tanaka
- Department of Neurobiology and Anatomy, Kochi Medical School, Kochi University, Nankoku, Kochi, Japan
| | - Toshio Yawata
- Department of Neurosurgery, Kochi Medical School, Kochi University, Nankoku, Kochi, Japan
| | - Shogo Shimizu
- Department of Pharmacology, Kochi Medical School, Kochi University, Nankoku, Kochi, Japan
| | - Suo Zou
- Department of Pharmacology, Kochi Medical School, Kochi University, Nankoku, Kochi, Japan
| | - Tetsuya Ueba
- Department of Neurosurgery, Kochi Medical School, Kochi University, Nankoku, Kochi, Japan
| | - Kazunari Yuri
- Department of Neurobiology and Anatomy, Kochi Medical School, Kochi University, Nankoku, Kochi, Japan
| | - Motoaki Saito
- Department of Pharmacology, Kochi Medical School, Kochi University, Nankoku, Kochi, Japan
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16
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Zhao C, Zhao J, Yang Q, Ye Y. Cobra neurotoxin produces central analgesic and hyperalgesic actions via adenosine A 1 and A 2A receptors. Mol Pain 2018; 13:1744806917720336. [PMID: 28758541 PMCID: PMC5542074 DOI: 10.1177/1744806917720336] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Cobra neurotoxin, a short-chain peptide isolated from snake venom of Naja naja atra, showed both a central analgesic effect and a hyperalgesic effect in mice tests. In order to explore mechanisms, a hypothesis is put forward that cobra neurotoxin takes effect through adenosine receptor pathway. The central effects of cobra neurotoxin were evaluated using the hot plate test (a model of acute pain) and the spinal cord injury (a model of central pain) in mice and using A1 receptor antagonist (DPCPX) and A2A receptor antagonist (ZM241385); behaviors were scored and signal molecules such as reactive oxygen species and adenosine triphosphate levels and mitogen-activated protein kinases/extracellular signal-regulated protein kinase expression were measured. Low dose of cobra neurotoxin (25 µg/kg) had analgesic effects which were inhibited by DPCPX, while high dose of cobra neurotoxin (100 µg/kg) had hyperalgesic effects which were blocked by ZM241385. Cobra neurotoxin reduced reactive oxygen species and increased adenosine triphosphate in brain tissues, and extracellular signal-regulated protein kinase expression was markedly inhibited by cobra neurotoxin. Cobra neurotoxin may take effect through mitogen-activated protein kinases/extracellular signal-regulated protein kinase pathway inhibition by activating adenosine A1Rs and cause changes of reactive oxygen species and adenosine triphosphate through feedback mechanisms. Overdose cobra neurotoxin further activates the adenosine A2ARs to generate pain sensitization. This research proposes a new central analgesic mechanism of cobra neurotoxin and discloses dual regulation of pain.
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Affiliation(s)
- Chuang Zhao
- Department of Pharmaceutical Engineering, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou, China
| | - Jun Zhao
- Department of Pharmaceutical Engineering, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou, China
| | - Qian Yang
- Department of Pharmaceutical Engineering, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou, China
| | - Yong Ye
- Department of Pharmaceutical Engineering, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou, China
- Key Laboratory of Functional Molecular Engineering of Guangdong Province, Guangzhou, China
- Yong Ye, Department of Pharmaceutical Engineering, School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510640, China.
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17
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Wong DF, Kuwabara H, Horti AG, Roberts JM, Nandi A, Cascella N, Brasic J, Weerts EM, Kitzmiller K, Phan JA, Gapasin L, Sawa A, Valentine H, Wand G, Mishra C, George N, McDonald M, Lesniak W, Holt DP, Azad BB, Dannals RF, Kem W, Freedman R, Gjedde A. Brain PET Imaging of α7-nAChR with [18F]ASEM: Reproducibility, Occupancy, Receptor Density, and Changes in Schizophrenia. Int J Neuropsychopharmacol 2018; 21. [PMID: 29522184 PMCID: PMC6030963 DOI: 10.1093/ijnp/pyy021] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
BACKGROUND The α7 nicotinic acetylcholine receptor increasingly has been implicated in normal brain physiology, as well as in neuropsychiatric disorders. The highly cortical distribution of α7 nicotinic acetylcholine receptor suggests a role in cognition. METHODS We expanded the first-in-human PET imaging of α7 nicotinic acetylcholine receptor with [18F]ASEM from 5 to 21 healthy nonsmoking volunteers and added a feasibility study in 6 male patients with schizophrenia. Study aims included: (1) confirmation of test-retest reproducibility of [18F]ASEM binding, (2) demonstration of specificity by competition with DMXB-A, an α7 nicotinic acetylcholine receptor partial agonist, (3) estimation of [18F]ASEM binding potentials and α7 nicotinic acetylcholine receptor density in vivo in humans, and (4) demonstrating the feasibility of studying α7 nicotinic acetylcholine receptor as a target for schizophrenia. RESULTS Test-retest PET confirmed reproducibility (>90%) (variability ≤7%) of [18F]ASEM volume of distribution (VT) estimates in healthy volunteers. Repeated sessions of PET in 5 healthy subjects included baseline and effect of inhibition after oral administration of 150 mg DMXB-A. From reduction of binding potentials, we estimated the dose-dependent occupancy of α7 nicotinic acetylcholine receptor by DMXB-A at 17% to 49% for plasma concentrations at 60 to 200 nM DMXB-A. In agreement with evidence postmortem, α7 nicotinic acetylcholine receptor density averaged 0.67 to 0.82 nM and inhibitor affinity constant averaged 170 to 385 nM. Median VT in a feasibility study of 6 patients with schizophrenia was lower than in healthy volunteers in cingulate cortex, frontal cortex, and hippocampus (P = 0.02, corrected for multiple comparions, Mann-Whitney test). CONCLUSIONS The current results confirm the reproducibility of [18F]ASEM VT estimates and the specificity of the tracer for α7 nicotinic acetylcholine receptor. Preliminary findings from our feasibility study of [18F]ASEM binding in patients with schizophrenia are suggestive and provide guidance for future studies with more subjects.
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Affiliation(s)
- Dean F Wong
- Russell H. Morgan Department of Radiology and Radiological Sciences, Baltimore, Maryland,Department of Psychiatry and Behavioral Sciences, Baltimore, Maryland,Solomon Snyder Department of Neuroscience, Baltimore, Maryland,Department of Neurology, Baltimore, Maryland,Johns Hopkins University School of Medicine, Baltimore, Maryland,Correspondence: Dean F. Wong, MD, PhD, Radiology, Nuclear Medicine, Johns Hopkins Medical Institutions, JHOC Room 3244, Baltimore, MD ()
| | - Hiroto Kuwabara
- Russell H. Morgan Department of Radiology and Radiological Sciences, Baltimore, Maryland
| | - Andrew G Horti
- Russell H. Morgan Department of Radiology and Radiological Sciences, Baltimore, Maryland
| | - Joshua M Roberts
- Russell H. Morgan Department of Radiology and Radiological Sciences, Baltimore, Maryland
| | - Ayon Nandi
- Russell H. Morgan Department of Radiology and Radiological Sciences, Baltimore, Maryland
| | - Nicola Cascella
- Russell H. Morgan Department of Radiology and Radiological Sciences, Baltimore, Maryland,Sheppard-Pratt Hospital, Baltimore, Maryland
| | - James Brasic
- Russell H. Morgan Department of Radiology and Radiological Sciences, Baltimore, Maryland
| | - Elise M Weerts
- Department of Psychiatry and Behavioral Sciences, Baltimore, Maryland
| | - Kelly Kitzmiller
- Russell H. Morgan Department of Radiology and Radiological Sciences, Baltimore, Maryland
| | - Jenny A Phan
- Russell H. Morgan Department of Radiology and Radiological Sciences, Baltimore, Maryland,Department of Biomedicine, Aarhus University, Aarhus, Denmark,Department of Nuclear Medicine and PET Centre, Aarhus University Hospital, Aarhus, Denmark
| | - Lorena Gapasin
- Russell H. Morgan Department of Radiology and Radiological Sciences, Baltimore, Maryland
| | - Akira Sawa
- Department of Psychiatry and Behavioral Sciences, Baltimore, Maryland
| | - Heather Valentine
- Russell H. Morgan Department of Radiology and Radiological Sciences, Baltimore, Maryland
| | - Gary Wand
- Department of Psychiatry and Behavioral Sciences, Baltimore, Maryland,Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Chakradhar Mishra
- Russell H. Morgan Department of Radiology and Radiological Sciences, Baltimore, Maryland
| | - Noble George
- Russell H. Morgan Department of Radiology and Radiological Sciences, Baltimore, Maryland
| | - Michael McDonald
- Russell H. Morgan Department of Radiology and Radiological Sciences, Baltimore, Maryland
| | - Wojtek Lesniak
- Russell H. Morgan Department of Radiology and Radiological Sciences, Baltimore, Maryland
| | - Daniel P Holt
- Russell H. Morgan Department of Radiology and Radiological Sciences, Baltimore, Maryland
| | - Babak B Azad
- Russell H. Morgan Department of Radiology and Radiological Sciences, Baltimore, Maryland
| | - Robert F Dannals
- Russell H. Morgan Department of Radiology and Radiological Sciences, Baltimore, Maryland
| | - William Kem
- Russell H. Morgan Department of Radiology and Radiological Sciences, Baltimore, Maryland,Department of Pharmacology and Therapeutics, University of Florida, Gainesville, Florida
| | - Robert Freedman
- Department of Psychiatry, University of Colorado, Aurora, Colorado
| | - Albert Gjedde
- Russell H. Morgan Department of Radiology and Radiological Sciences, Baltimore, Maryland,Department of Nuclear Medicine, University of Southern Denmark, Odense, Denmark
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18
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Cartereau A, Martin C, Thany SH. Neonicotinoid insecticides differently modulate acetycholine-induced currents on mammalian α7 nicotinic acetylcholine receptors. Br J Pharmacol 2017; 175:1987-1998. [PMID: 28853147 DOI: 10.1111/bph.14018] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2017] [Revised: 08/11/2017] [Accepted: 08/17/2017] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND AND PURPOSE Neonicotinoid insecticides are described as poor agonists of mammalian nicotinic ACh receptors. In this paper, we show that their effects on mammalian nicotinic receptors differ between compounds. EXPERIMENTAL APPROACH Two-electrode voltage-clamp electrophysiology was used to characterize the pharmacology of three neonicotinoid insecticides on nicotinic α7 receptors expressed in Xenopus oocytes. Single and combined application of clothianidin, acetamiprid and thiamethoxam were tested. RESULTS Two neonicotinoid insecticides, clothianidin and acetamiprid, were partial agonists of mammalian neuronal α7 nicotinic receptors, whereas another neonicotinoid insecticide, thiamethoxam, which is converted to clothianidin in insect and plant tissues, had no effect. Pretreatment with clothianidin and acetamiprid (10 μM) ACh significantly enhanced the subsequent currents evoked by ACh (100 μM ) whereas pretreatment with thiamethoxam (10 μM) reduced ACh-induced current amplitudes.A combination of the three neonicotinoids decreased the ACh-evoked currents. CONCLUSIONS AND IMPLICATIONS The present findings suggest that neonicotinoid insecticides differ markedly in their direct effects on mammalian α7 nicotinic ACh receptors and can also modulate ACh-induced currents. Furthermore, our data indicate a previously unknown modulation of mammalian α7 nicotinic receptors by a combination of clothianidin, acetamiprid and thiamethoxam. 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)
- Alison Cartereau
- LBLGC, UPRES EA 1207-USC INRA 1328, Université d'Orléans, Orléans, France
| | - Carine Martin
- LBLGC, UPRES EA 1207-USC INRA 1328, Université d'Orléans, Orléans, France
| | - Steeve H Thany
- LBLGC, UPRES EA 1207-USC INRA 1328, Université d'Orléans, Orléans, France
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19
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20
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Filer CN. Tritium-labelled alkaloids: Synthesis and applications. J Labelled Comp Radiopharm 2017; 60:96-109. [DOI: 10.1002/jlcr.3480] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Revised: 10/12/2016] [Accepted: 11/01/2016] [Indexed: 11/06/2022]
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21
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Brown DP, Rogers DT, Pomerleau F, Siripurapu KB, Kulshrestha M, Gerhardt GA, Littleton JM. Novel multifunctional pharmacology of lobinaline, the major alkaloid from Lobelia cardinalis. Fitoterapia 2016; 111:109-23. [PMID: 27105955 PMCID: PMC5299595 DOI: 10.1016/j.fitote.2016.04.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Revised: 04/15/2016] [Accepted: 04/17/2016] [Indexed: 01/18/2023]
Abstract
In screening a library of plant extracts from ~1000 species native to the Southeastern United States, Lobelia cardinalis was identified as containing nicotinic acetylcholine receptor (nicAchR) binding activity which was relatively non-selective for the α4β2- and α7-nicAchR subtypes. This nicAchR binding profile is atypical for plant-derived nicAchR ligands, the majority of which are highly selective for α4β2-nicAchRs. Its potential therapeutic relevance is noteworthy since agonism of α4β2- and α7-nicAchRs is associated with anti-inflammatory and neuroprotective properties. Bioassay-guided fractionation of L. cardinalis extracts led to the identification of lobinaline, a complex binitrogenous alkaloid, as the main source of the unique nicAchR binding profile. Purified lobinaline was a potent free radical scavenger, displayed similar binding affinity at α4β2- and α7-nicAchRs, exhibited agonist activity at nicAchRs in SH-SY5Y cells, and inhibited [(3)H]-dopamine (DA) uptake in rat striatal synaptosomes. Lobinaline significantly increased fractional [(3)H] release from superfused rat striatal slices preloaded with [(3)H]-DA, an effect that was inhibited by the non-selective nicAchR antagonist mecamylamine. In vivo electrochemical studies in urethane-anesthetized rats demonstrated that lobinaline locally applied in the striatum significantly prolonged clearance of exogenous DA by the dopamine transporter (DAT). In contrast, lobeline, the most thoroughly investigated Lobelia alkaloid, is an α4β2-nicAchR antagonist, a poor free radical scavenger, and is a less potent DAT inhibitor. These previously unreported multifunctional effects of lobinaline make it of interest as a lead to develop therapeutics for neuropathological disorders that involve free radical generation, cholinergic, and dopaminergic neurotransmission. These include neurodegenerative conditions, such as Parkinson's disease, and drug abuse.
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Affiliation(s)
- Dustin P Brown
- College of Medicine, Department of Anatomy & Neurobiology, University of Kentucky Chandler Medical Center, 138 Leader Avenue, Lexington, KY 40536-9983, USA
| | - Dennis T Rogers
- Naprogenix™, UK-AsTeCC, 145 Graham Avenue, Lexington, KY 40506-0286, USA.
| | - Francois Pomerleau
- College of Medicine, Department of Anatomy & Neurobiology, University of Kentucky Chandler Medical Center, 138 Leader Avenue, Lexington, KY 40536-9983, USA; College of Medicine, Parkinson's Disease Translational Research Center for Excellence, University of Kentucky Chandler Medical Center, 138 Leader Avenue, Lexington, KY 40536-9983, USA; College of Medicine, Center for Microelectrode Technology, University of Kentucky Chandler Medical Center, 138 Leader Avenue, Lexington, KY 40536-9983, USA
| | - Kirin B Siripurapu
- College of Arts and Sciences, Department of Psychology, University of Kentucky, Kastle Hall, Lexington, KY 40506-0044, USA
| | - Manish Kulshrestha
- College of Agriculture, Department of Biosystems & Agricultural Engineering, University of Kentucky, 1100 S. Limestone, Lexington, KY 40546-0091, USA
| | - Greg A Gerhardt
- College of Medicine, Department of Anatomy & Neurobiology, University of Kentucky Chandler Medical Center, 138 Leader Avenue, Lexington, KY 40536-9983, USA; College of Medicine, Department of Neurology, University of Kentucky Chandler Medical Center, 138 Leader Avenue, Lexington, KY 40536-9983, USA; College of Medicine, Department of Psychiatry, University of Kentucky Chandler Medical Center, 138 Leader Avenue, Lexington, KY 40536-9983, USA; College of Medicine, Department of Neurosurgery, University of Kentucky Chandler Medical Center, 138 Leader Avenue, Lexington, KY 40536-9983, USA; College of Medicine, Parkinson's Disease Translational Research Center for Excellence, University of Kentucky Chandler Medical Center, 138 Leader Avenue, Lexington, KY 40536-9983, USA; College of Medicine, Center for Microelectrode Technology, University of Kentucky Chandler Medical Center, 138 Leader Avenue, Lexington, KY 40536-9983, USA
| | - John M Littleton
- Naprogenix™, UK-AsTeCC, 145 Graham Avenue, Lexington, KY 40506-0286, USA; College of Arts and Sciences, Department of Psychology, University of Kentucky, Kastle Hall, Lexington, KY 40506-0044, USA
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Chalon S, Vercouillie J, Guilloteau D, Suzenet F, Routier S. PET tracers for imaging brain α7 nicotinic receptors: an update. Chem Commun (Camb) 2016; 51:14826-31. [PMID: 26359819 DOI: 10.1039/c5cc04536c] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Positron emission tomography (PET) molecular imaging of brain targets is a powerful tool to diagnose, follow up, and develop treatments and personalized medicine for a number of acute and chronic brain disorders. The availability of β+ emitter tracers labelled with [(11)C] or [(18)F] having optimal characteristics of affinity and selectivity for alpha-7 nicotinic receptors (α7R) has received considerable attention, due to the major implication of these receptors in brain functions. The aim of this review is to identify the interest and need for the in vivo exploration of α7R by PET molecular imaging, which tools are currently available for this and how to progress.
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Affiliation(s)
- S Chalon
- UMR Inserm U930, Université François-Rabelais de Tours, F-37000 Tours, France.
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Manetti D, Bellucci C, Dei S, Teodori E, Varani K, Spirova E, Kudryavtsev D, Shelukhina I, Tsetlin V, Romanelli MN. New quinoline derivatives as nicotinic receptor modulators. Eur J Med Chem 2016; 110:246-58. [DOI: 10.1016/j.ejmech.2016.01.025] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Revised: 01/14/2016] [Accepted: 01/15/2016] [Indexed: 11/30/2022]
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Kolar FR, Ghatge SR, Pawar NV, Dixit GB. RP-HPLC Analysis of an Alkaloid–Methyllycaconitine from Mutagenic Delphinium malabaricum (Huth) Munz. J LIQ CHROMATOGR R T 2015. [DOI: 10.1080/10826076.2015.1110706] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
- Firdose R. Kolar
- Laboratory of Cytogenetics and Plant Breeding, Department of Botany, Shivaji University, Kolhapur, India
| | - Swaroopa R. Ghatge
- Laboratory of Cytogenetics and Plant Breeding, Department of Botany, Shivaji University, Kolhapur, India
| | - Nilesh V. Pawar
- Laboratory of Cytogenetics and Plant Breeding, Department of Botany, Shivaji University, Kolhapur, India
| | - Ghansham B. Dixit
- Laboratory of Cytogenetics and Plant Breeding, Department of Botany, Shivaji University, Kolhapur, India
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Tang JS, Xie BX, Bian XL, Xue Y, Wei NN, Zhou JH, Hao YC, Li G, Zhang LR, Wang KW. Identification and in vitro pharmacological characterization of a novel and selective α7 nicotinic acetylcholine receptor agonist, Br-IQ17B. Acta Pharmacol Sin 2015; 36:800-12. [PMID: 25948478 PMCID: PMC4648113 DOI: 10.1038/aps.2015.9] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Accepted: 03/03/2015] [Indexed: 12/14/2022] Open
Abstract
Aim: Alpha7-nicotinic acetylcholine receptor (α7 nAChR) is a ligand-gated Ca2+-permeable ion channel implicated in cognition and neuropsychiatric disorders. Activation of α7 nAChR improves learning, memory, and sensory gating in animal models. To identify novel α7 nAChR agonists, we synthesized a series of small molecules and characterized a representative compound, Br-IQ17B, N-[(3R)-1-azabicyclo[2,2,2]oct-3-yl]-5-bromoindolizine-2-carboxamide, which specifically activates α7 nAChR. Methods: Two-electrode voltage clamp (TEVC) recordings were primarily used for screening in Xenopus oocytes expressing human α7 nAChR. Assays, including radioisotope ligand binding, Western blots, whole-cell recordings of hippocampal culture neurons, and spontaneous IPSC recordings of brain slices, were also utilized to evaluate and confirm the specific activation of α7 nAChR by Br-IQ17B. Results: Br-IQ17B potently activates α7 nAChR with an EC50 of 1.8±0.2 μmol/L. Br-IQ17B is selective over other subtypes such as α4β2 and α3β4, but it blocks 5-HT3A receptors. Br-IQ17B displaced binding of the α7 blocker [3H]-MLA to hippocampal crude membranes with a Ki of 14.9±3.2 nmol/L. In hippocampal neurons, Br-IQ17B evoked α7-like currents that were inhibited by MLA and enhanced in the presence of the α7 PAM PNU-120596. In brain slice recordings, Br-IQ17B enhanced GABAergic synaptic transmission in CA1 neurons. Mechanistically, Br-IQ17B increased ERK1/2 phosphorylation that was MLA-sensitive. Conclusion: We identified the novel, potent, and selective α7 agonist Br-IQ17B, which enhances synaptic transmission. Br-IQ17B may be a helpful tool to understand new aspects of α7 nAChR function, and it also has potential for being developed as therapy for schizophrenia and cognitive deficits.
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Biomolecular recognition of antagonists by α7 nicotinic acetylcholine receptor: Antagonistic mechanism and structure-activity relationships studies. Eur J Pharm Sci 2015; 76:119-32. [PMID: 25963024 DOI: 10.1016/j.ejps.2015.05.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Revised: 04/24/2015] [Accepted: 05/06/2015] [Indexed: 12/20/2022]
Abstract
As the key constituent of ligand-gated ion channels in the central nervous system, nicotinic acetylcholine receptors (nAChRs) and neurodegenerative diseases are strongly coupled in the human species. In recently years the developments of selective agonists by using nAChRs as the drug target have made a large progress, but the studies of selective antagonists are severely lacked. Currently these antagonists rest mainly on the extraction of partly natural products from some animals and plants; however, the production of these crude substances is quite restricted, and artificial synthesis of nAChR antagonists is still one of the completely new research fields. In the context of this manuscript, our primary objective was to comprehensively analyze the recognition patterns and the critical interaction descriptors between target α7 nAChR and a series of the novel compounds with potentially antagonistic activity by means of virtual screening, molecular docking and molecular dynamics simulation, and meanwhile these recognition reactions were also compared with the biointeraction of α7 nAChR with a commercially natural antagonist - methyllycaconitine. The results suggested clearly that there are relatively obvious differences of molecular structures between synthetic antagonists and methyllycaconitine, while the two systems have similar recognition modes on the whole. The interaction energy and the crucially noncovalent forces of the α7 nAChR-antagonists are ascertained according to the method of Molecular Mechanics/Generalized Born Surface Area. Several amino acid residues, such as B/Tyr-93, B/Lys-143, B/Trp-147, B/Tyr-188, B/Tyr-195, A/Trp-55 and A/Leu-118 played a major role in the α7 nAChR-antagonist recognition processes, in particular, residues B/Tyr-93, B/Trp-147 and B/Tyr-188 are the most important. These outcomes tally satisfactorily with the discussions of amino acid mutations. Based on the explorations of three-dimensional quantitative structure-activity relationships, the structure-antagonistic activity relationships of antagonists and the characteristics of α7 nAChR-ligand recognitions were received a reasonable summary as well. These attempts emerged herein would not only provide helpful guidance for the design of α7 nAChR antagonists, but shed new light on the subsequent researches in antagonistic mechanism.
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The inimitable kynurenic acid: The roles of different ionotropic receptors in the action of kynurenic acid at a spinal level. Brain Res Bull 2015; 112:52-60. [DOI: 10.1016/j.brainresbull.2015.02.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Revised: 01/08/2015] [Accepted: 02/02/2015] [Indexed: 10/24/2022]
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Abstract
Facilitation of different attentional functions by nicotinic acetylcholine receptor (nAChR) agonists may be of therapeutic potential in disease conditions such as Alzheimer's disease or schizophrenia. For this reason, the neuronal mechanisms underlying these effects have been the focus of research in humans and in preclinical models. Attention-enhancing effects of the nonselective nAChR agonist nicotine can be observed in human nonsmokers and in laboratory animals, suggesting that benefits go beyond a reversal of withdrawal deficits in smokers. The ultimate aim is to develop compounds acting with greater selectivity than nicotine at a subset of nAChRs, with an effects profile narrowly matching the targeted cognitive deficits and minimizing unwanted effects. To date, compounds tested clinically target the nAChR subtypes most abundant in the brain. To help pinpoint more selectively expressed subtypes critical for attention, studies have aimed at identifying the secondary neurotransmitter systems whose stimulation mediates the attention-enhancing properties of nicotine. Evidence indicates that noradrenaline and glutamate, but not dopamine release, are critical mediators. Thus, attention-enhancing nAChR agents could spare the system central to nicotine dependence. Neuroimaging studies suggest that nAChR agonists act on a variety of brain systems by enhancing activation, reducing activation, and enhancing deactivation by attention tasks. This supports the notion that effects on different attentional functions may be mediated by distinct central mechanisms, consistent with the fact that nAChRs interact with a multitude of brain sites and neurotransmitter systems. The challenge will be to achieve the optimal tone at the right subset of nAChR subtypes to modulate specific attentional functions, employing not just direct agonist properties, but also positive allosteric modulation and low-dose antagonism.
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Affiliation(s)
- Britta Hahn
- Maryland Psychiatric Research Center, University of Maryland School of Medicine, Baltimore, MD, USA,
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Arias HR, Feuerbach D, Targowska-Duda K, Kaczor AA, Poso A, Jozwiak K. Pharmacological and molecular studies on the interaction of varenicline with different nicotinic acetylcholine receptor subtypes. Potential mechanism underlying partial agonism at human α4β2 and α3β4 subtypes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2014; 1848:731-41. [PMID: 25475645 DOI: 10.1016/j.bbamem.2014.11.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2014] [Revised: 10/29/2014] [Accepted: 11/06/2014] [Indexed: 02/06/2023]
Abstract
To determine the structural components underlying differences in affinity, potency, and selectivity of varenicline for several human (h) nicotinic acetylcholine receptors (nAChRs), functional and structural experiments were performed. The Ca2+ influx results established that: (a) varenicline activates (μM range) nAChR subtypes with the following rank sequence: hα7>hα4β4>hα4β2>hα3β4>>>hα1β1γδ; (b) varenicline binds to nAChR subtypes with the following affinity order (nM range): hα4β2~hα4β4>hα3β4>hα7>>>Torpedo α1β1γδ. The molecular docking results indicating that more hydrogen bond interactions are apparent for α4-containing nAChRs in comparison to other nAChRs may explain the observed higher affinity; and that (c) varenicline is a full agonist at hα7 (101%) and hα4β4 (93%), and a partial agonist at hα4β2 (20%) and hα3β4 (45%), relative to (±)-epibatidine. The allosteric sites found at the extracellular domain (EXD) of hα3β4 and hα4β2 nAChRs could explain the partial agonistic activity of varenicline on these nAChR subtypes. Molecular dynamics simulations show that the interaction of varenicline to each allosteric site decreases the capping of Loop C at the hα4β2 nAChR, suggesting that these allosteric interactions limit the initial step in the gating process. In conclusion, we propose that in addition to hα4β2 nAChRs, hα4β4 nAChRs can be considered as potential targets for the clinical activity of varenicline, and that the allosteric interactions at the hα3β4- and hα4β2-EXDs are alternative mechanisms underlying partial agonism at these nAChRs.
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Affiliation(s)
- Hugo R Arias
- Department of Medical Education, California Northstate University College of Medicine, Elk Grove, CA, USA.
| | - Dominik Feuerbach
- Neuroscience Research, Novartis Institutes for Biomedical Research, Basel, Switzerland
| | - Katarzyna Targowska-Duda
- Department of Chemistry, Laboratory of Medicinal Chemistry and Neuroengineering, Medical University of Lublin, Lublin, Poland
| | - Agnieszka A Kaczor
- Department of Synthesis and Chemical Technology of Pharmaceutical Substances with Computer Modeling Lab, Medical University of Lublin, Lublin, Poland
| | - Antti Poso
- School of Pharmacy, University of Eastern Finland, Kuopio, Finland
| | - Krzysztof Jozwiak
- Department of Chemistry, Laboratory of Medicinal Chemistry and Neuroengineering, Medical University of Lublin, Lublin, Poland
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Lutz JA, Kulshrestha M, Rogers DT, Littleton JM. A nicotinic receptor-mediated anti-inflammatory effect of the flavonoid rhamnetin in BV2 microglia. Fitoterapia 2014; 98:11-21. [PMID: 24972350 PMCID: PMC4171190 DOI: 10.1016/j.fitote.2014.06.012] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2014] [Revised: 06/13/2014] [Accepted: 06/17/2014] [Indexed: 11/26/2022]
Abstract
The alpha7 nicotinic acetylcholine receptor (nAChR) is a potential target in neuroinflammation. Screening a plant extract library identified Solidago nemoralis as containing methyl-quercetin derivatives that are relatively selective ligands for the alpha7 nAChR. Flavonoids are not known for this activity, so we screened a small library of pure flavonoids to confirm our findings. Some flavonoids, e.g. rhamnetin, displaced a selective alpha7 nAChR radioligand from rat brain membranes whereas similar structures e.g. sakuranetin, did not. To evaluate the contribution of this putative nAChR activity to the known anti-inflammatory properties of these flavonoids, we compared their effects on lipopolysaccharide induced release of inflammatory mediators from BV2 microglia. Both rhamnetin and sakuranetin reduced mediator release, but differed in potency (rhamnetin>sakuranetin) and the Hill slope of their concentration-response curves. For rhamnetin the Hill coefficient was >3.0 whereas for sakuranetin the coefficient was 1.0, suggesting that effects of rhamnetin are mediated through more than one mechanism, whereas sakuranetin has a single mechanism. nAChR antagonists decreased the Hill coefficient for rhamnetin toward unity, which suggests that a nAChR-mediated mechanism contributes cooperatively to its overall anti-inflammatory effect. In contrast nAChR antagonists had no effect on the potency or Hill coefficient for sakuranetin, but a concentration of nicotine (1μM) that had no effect alone, significantly increased the Hill coefficient of this flavonoid. In conclusion, the anti-inflammatory effects of rhamnetin benefit cooperatively from a nAChR-mediated mechanism. This action, together with potent free radical scavenging activity, suggests that flavonoids with alpha7 nAChR activity have therapeutic potential in neuroinflammatory conditions.
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Affiliation(s)
- Joseph A Lutz
- College of Pharmacy, Department of Pharmaceutical Sciences, University of Kentucky, 789 S. Limestone, Lexington, KY 40506-0596, USA
| | - Manish Kulshrestha
- College of Agriculture, Department of Biosystems & Agricultural Engineering, University of Kentucky, 1100 S. Limestone, Lexington, KY 40546-0091, USA
| | - Dennis T Rogers
- Naprogenix™, UK-AsTeCC, 145 Graham Avenue, Lexington, KY 40506-0286, USA
| | - John M Littleton
- College of Arts and Sciences, Department of Psychology, University of Kentucky, Kastle Hall, Lexington, KY 40506-0044, USA.
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Development of (18)F-labeled radiotracers for neuroreceptor imaging with positron emission tomography. Neurosci Bull 2014; 30:777-811. [PMID: 25172118 DOI: 10.1007/s12264-014-1460-6] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2014] [Accepted: 06/02/2014] [Indexed: 12/14/2022] Open
Abstract
Positron emission tomography (PET) is an in vivo molecular imaging tool which is widely used in nuclear medicine for early diagnosis and treatment follow-up of many brain diseases. PET uses biomolecules as probes which are labeled with radionuclides of short half-lives, synthesized prior to the imaging studies. These probes are called radiotracers. Fluorine-18 is a radionuclide routinely used in the radiolabeling of neuroreceptor ligands for PET because of its favorable half-life of 109.8 min. The delivery of such radiotracers into the brain provides images of transport, metabolic, and neurotransmission processes on the molecular level. After a short introduction into the principles of PET, this review mainly focuses on the strategy of radiotracer development bridging from basic science to biomedical application. Successful radiotracer design as described here provides molecular probes which not only are useful for imaging of human brain diseases, but also allow molecular neuroreceptor imaging studies in various small-animal models of disease, including genetically-engineered animals. Furthermore, they provide a powerful tool for in vivo pharmacology during the process of pre-clinical drug development to identify new drug targets, to investigate pathophysiology, to discover potential drug candidates, and to evaluate the pharmacokinetics and pharmacodynamics of drugs in vivo.
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Lee L, Kosuri P, Arancio O. Picomolar amyloid-β peptides enhance spontaneous astrocyte calcium transients. J Alzheimers Dis 2014; 38:49-62. [PMID: 23948929 DOI: 10.3233/jad-130740] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Amyloid-β (Aβ) peptides are constitutively produced in the brain throughout life via mechanisms that can be regulated by synaptic activity. Although Aβ has been extensively studied as the pathological plaque-forming protein species in Alzheimer's disease (AD), little is known about the normal physiological function(s) and signaling pathway(s). We previously discovered that physiologically-relevant, low picomolar amounts of Aβ can enhance synaptic plasticity and hippocampal-dependent cognition in mice. In this study, we demonstrated that astrocytes are cellular candidates for participating in this type of Aβ signaling. Using calcium imaging of primary astrocyte cultures, we observed that picomolar amounts of Aβ peptides can enhance spontaneous intracellular calcium transient signaling. After application of 200 pM Aβ42 peptides, the frequency and amplitude averages of spontaneous cytosolic calcium transients were significantly increased. These effects were dependent on α7 nicotinic acetylcholine receptors (α7-nAChRs), as the enhancement effects were blocked by a pharmacological α7-nAChR inhibitor and in astrocytes from an α7 deficient mouse strain. We additionally examined evoked intercellular calcium wave signaling but did not detect significant picomolar Aβ-induced alterations in propagation parameters. Overall, these results indicate that at a physiologically-relevant low picomolar concentration, Aβ peptides can enhance spontaneous astrocyte calcium transient signaling via α7-nAChRs. Since astrocyte-mediated gliotransmission has been previously found to have neuromodulatory roles, Aβ peptides may have a normal physiological function in regulating neuron-glia signaling. Dysfunction of this signaling process may underlie glia-based aspects of AD pathogenesis.
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Affiliation(s)
- Linda Lee
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University, New York, NY, USA Department of Pathology and Cell Biology, Columbia University, New York, NY, USA Center for Neurobiology and Behavior, Columbia University, New York, NY, USA
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Andriambeloson E, Huyard B, Poiraud E, Wagner S. Methyllycaconitine- and scopolamine-induced cognitive dysfunction: differential reversal effect by cognition-enhancing drugs. Pharmacol Res Perspect 2014; 2:e00048. [PMID: 25505596 PMCID: PMC4186438 DOI: 10.1002/prp2.48] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Accepted: 03/26/2014] [Indexed: 12/14/2022] Open
Abstract
There is a growing body of evidence pointing to the pivotal role of alpha-7 nicotinic acetylcholine receptor (α7 nAchR) dysfunction in cognitive disorders such as Alzheimer’s disease or schizophrenia. This study was undertaken to establish and characterize an in vivo model for cognitive disorder secondary to the blockade of α7 nAChR by its specific antagonist, methyllycaconitine (MLA). The results show that MLA elicited cognitive dysfunction as assessed by reduced spontaneous alternation of mice in the T-maze. The maximal effect of MLA produced 25–30% reduction in the spontaneous alternation of mice, a level comparable with that induced by the muscarinic antagonism of scopolamine. Donepezil and galantamine fully reversed both MLA and scopolamine-induced cognitive dysfunction. However, the ED50 of donepezil and galantamine was significantly shifted to the left in the MLA- compared to scopolamine-treated mice (0.0005 and 0.002 mg/kg for donepezil; 0.0003 and 0.7 mg/kg for galantamine). Moreover, memantine elicited marked reversion of cognitive dysfunction (up to 70%) in MLA-treated mice while only a weak reversal effect at high dose of memantine (less than 20%) was observed in scopolamine-treated mice. The above findings indicate that MLA-induced cognitive dysfunction in the mouse is highly sensitive and more responsive to the current procognitive drugs than the traditional scopolamine-based assay. Thus, it can be of value for the preclinical screening and profiling of cognition-enhancing drugs.
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Affiliation(s)
- Emile Andriambeloson
- Neurofit SAS boulevard Sébastien Brant, Bioparc Parc d'Innovation, 674.00, Illkirch, France
| | - Bertrand Huyard
- Neurofit SAS boulevard Sébastien Brant, Bioparc Parc d'Innovation, 674.00, Illkirch, France
| | - Etienne Poiraud
- Neurofit SAS boulevard Sébastien Brant, Bioparc Parc d'Innovation, 674.00, Illkirch, France
| | - Stéphanie Wagner
- Neurofit SAS boulevard Sébastien Brant, Bioparc Parc d'Innovation, 674.00, Illkirch, France
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Gannon RL, Garcia DA, Millan MJ. Effects of systemically applied nAChRα7 agonists and antagonists on light-induced phase shifts of hamster circadian activity rhythms. Eur Neuropsychopharmacol 2014; 24:964-73. [PMID: 24388152 DOI: 10.1016/j.euroneuro.2013.12.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2013] [Revised: 12/03/2013] [Accepted: 12/08/2013] [Indexed: 12/25/2022]
Abstract
Many physiological systems in mammals are linked to the body's master circadian rhythm in the sleep/wake cycle and dysfunctions in this rhythm has been associated with neurological diseases such as major depression, Alzheimer's Disease and schizophrenia. There is some evidence that nicotinic cholinergic input to the master circadian pacemaker, the suprachiasmatic nucleus, may modulate circadian activity rhythms, but data employing in vivo preparations is sparse. Therefore we examined the ability of intraperitoneally applied nicotinic agonists and antagonists relatively selective for the α7 nicotinic receptor to modulate light-induced phase shifts of hamster circadian wheel running rhythms. Hamsters were maintained in constant darkness and exposed to light pulses early and late in their active period, mimicking dusk and dawn respectively, which elicited phase delays and advances of their circadian wheel running rhythms. The α7 receptor antagonists bPiDDB (0.03-3mg/kg) and methyllacaconitine (0.1-1mg/kg) inhibited both light- induced phase advances and delays of circadian wheel running rhythms by as much as 75% versus vehicle injections. In contrast, systemic injections of the α7 agonists PHA 543613 and ABT107, both at 0.156-2.5mg/kg, had no effect on light induced phase advances or delays. Further, α7 nicotinic receptors were identified in the hamster suprachiasmatic nucleus using an antibody that recognizes α7 nicotinic receptors. These results clearly identify the ability of α7 nicotinic receptor antagonists to inhibit light-entrainment of the hamster circadian pacemaker. Therefore, nicotinic compounds may be useful for the treatment of circadian dysfunction associated with neurological diseases.
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Affiliation(s)
- Robert L Gannon
- Department of Biology, Valdosta State University, Valdosta, Georgia, USA.
| | - David A Garcia
- Department of Biology, Valdosta State University, Valdosta, Georgia, USA
| | - Mark J Millan
- Department of Psychopharmacology, Institut de Recherches Servier, Paris, France
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Arias HR, López JJ, Feuerbach D, Fierro A, Ortells MO, Pérez EG. Novel 2-(substituted benzyl)quinuclidines inhibit human α7 and α4β2 nicotinic receptors by different mechanisms. Int J Biochem Cell Biol 2013; 45:2420-30. [DOI: 10.1016/j.biocel.2013.08.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Revised: 07/11/2013] [Accepted: 08/06/2013] [Indexed: 01/12/2023]
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Prousis KC, Tzani A, Avlonitis N, Calogeropoulou T, Detsi A. Reactivity of 2-Methyl-4H-3,1-benzoxazin-4-ones and 2-Methyl-4H-pyrido[2,3-d][1,3]oxazin-4-one under Microwave Irradiation Conditions. J Heterocycl Chem 2013. [DOI: 10.1002/jhet.1869] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Kyriakos C. Prousis
- Laboratory of Organic Chemistry, Department of Chemical Sciences, School of Chemical Engineering; National Technical University of Athens; Heroon Polytechniou 9, Zografou Campus GR 15780 Athens Greece
- Institute of Biology, Medicinal Chemistry and Biotechnology; National Hellenic Research Foundation; 48 Vassileos Constantinou Avenue 116 35 Athens Greece
| | - Andromachi Tzani
- Laboratory of Organic Chemistry, Department of Chemical Sciences, School of Chemical Engineering; National Technical University of Athens; Heroon Polytechniou 9, Zografou Campus GR 15780 Athens Greece
| | - Nicolaos Avlonitis
- Institute of Biology, Medicinal Chemistry and Biotechnology; National Hellenic Research Foundation; 48 Vassileos Constantinou Avenue 116 35 Athens Greece
- Centre for Inflammation Research, The Queen's Medical Research Institute; MRC/University of Edinburgh; 47 Little France Crescent EH16 4TJ Edinburgh UK
| | - Theodora Calogeropoulou
- Institute of Biology, Medicinal Chemistry and Biotechnology; National Hellenic Research Foundation; 48 Vassileos Constantinou Avenue 116 35 Athens Greece
| | - Anastasia Detsi
- Laboratory of Organic Chemistry, Department of Chemical Sciences, School of Chemical Engineering; National Technical University of Athens; Heroon Polytechniou 9, Zografou Campus GR 15780 Athens Greece
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Absalom NL, Quek G, Lewis TM, Qudah T, von Arenstorff I, Ambrus JI, Harpsøe K, Karim N, Balle T, McLeod MD, Chebib M. Covalent trapping of methyllycaconitine at the α4-α4 interface of the α4β2 nicotinic acetylcholine receptor: antagonist binding site and mode of receptor inhibition revealed. J Biol Chem 2013; 288:26521-32. [PMID: 23893416 DOI: 10.1074/jbc.m113.475053] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The α4β2 nicotinic acetylcholine receptors (nAChRs) are widely expressed in the brain and are implicated in a variety of physiological processes. There are two stoichiometries of the α4β2 nAChR, (α4)2(β2)3 and (α4)3(β2)2, with different sensitivities to acetylcholine (ACh), but their pharmacological profiles are not fully understood. Methyllycaconitine (MLA) is known to be an antagonist of nAChRs. Using the two-electrode voltage clamp technique and α4β2 nAChRs in the Xenopus oocyte expression system, we demonstrate that inhibition by MLA occurs via two different mechanisms; that is, a direct competitive antagonism and an apparently insurmountable mechanism that only occurs after preincubation with MLA. We hypothesized an additional MLA binding site in the α4-α4 interface that is unique to this stoichiometry. To prove this, we covalently trapped a cysteine-reactive MLA analog at an α4β2 receptor containing an α4(D204C) mutation predicted by homology modeling to be within reach of the reactive probe. We demonstrate that covalent trapping results in irreversible reduction of ACh-elicited currents in the (α4)3(β2)2 stoichiometry, indicating that MLA binds to the α4-α4 interface of the (α4)3(β2)2 and providing direct evidence of ligand binding to the α4-α4 interface. Consistent with other studies, we propose that the α4-α4 interface is a structural target for potential therapeutics that modulate (α4)3(β2)2 nAChRs.
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Affiliation(s)
- Nathan L Absalom
- From the Faculty of Pharmacy, University of Sydney, Sydney, NSW 2006, Australia
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38
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Vukelic M, Qing X, Redecha P, Koo G, Salmon JE. Cholinergic receptors modulate immune complex-induced inflammation in vitro and in vivo. THE JOURNAL OF IMMUNOLOGY 2013; 191:1800-7. [PMID: 23851693 DOI: 10.4049/jimmunol.1203467] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Cholinergic neural output has been shown to modulate innate immune responses to infection, injury and ischemia through stimulation of α7 nicotinic acetylcholine receptors (α7nAChR) on mononuclear phagocytes. We tested the hypothesis that cholinergic neurotransmitters, similar to those released through activation of a neural reflex, regulate responses to products of the adaptive immune system, specifically immune complex (IC)-mediated activation of effector cells. In this study, we show that stimulation of α7nAChR on human polymorphonuclear neutrophils (PMNs) and blood mononuclear phagocytes in vitro attenuates C5aR- and FcγR-triggered generation of reactive oxygen species, expression of leukocyte markers involved in cell recruitment and adhesion, and release of TNF-α and other proinflammatory cytokines. We show that this pathway is operative in vivo. Ligation of cholinergic receptors blunts IC-triggered responses in the reverse peritoneal Arthus reaction in mice. The selective 7nAChR agonist GTS21 decreased PMN accumulation and release of cytokines and chemokines at sites of IC deposition. In addition, mice lacking α7nAChR had exaggerated responses to reverse peritoneal Arthus reaction characterized by increased infiltration of PMNs and elevated of levels of TNF-α and CXCL1 in peritoneal fluid compared with wild-type mice. Taken together, these findings suggest that cholinergic output has the potential to exert tonic inhibitory activity that dampens responses to ICs and C5a and thus may be a target to minimize tissue damage in autoimmune diseases.
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Affiliation(s)
- Milena Vukelic
- Program in Inflammation and Autoimmunity, Hospital for Special Surgery, Weill Cornell Medical College, New York, NY 10021, USA
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Ciudad-Roberts A, Camarasa J, Pubill D, Escubedo E. Heteromeric nicotinic receptors are involved in the sensitization and addictive properties of MDMA in mice. Prog Neuropsychopharmacol Biol Psychiatry 2013; 44:201-9. [PMID: 23466442 DOI: 10.1016/j.pnpbp.2013.02.013] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2012] [Revised: 01/30/2013] [Accepted: 02/21/2013] [Indexed: 12/12/2022]
Abstract
We have investigated the effect of nicotinic receptor ligands in the behavioral sensitization (hyperlocomotion) and rewarding properties (conditioned place preference paradigm, CPP) of 3,4-methylenedioxy-methamphetamine (MDMA) in mice. Each animal received intraperitoneal pretreatment with either saline, dihydro-β-erythroidine (DHβE, 1 mg/kg) or varenicline (VAR, 0.3 mg/kg), 15 min prior to subcutaneous saline or MDMA (5 mg/kg), for 10 consecutive days. On day 1, both DHβE and VAR inhibited the MDMA-induced hyperlocomotion. After 10 days of treatment, MDMA induced a hyperlocomotion that was not reduced (rather enhanced) in antagonist-pretreated animals. This early hyperlocomotion was accompanied by a significant increase in heteromeric nicotinic receptors in cortex that was not blocked by DHβE or VAR. Behavioral sensitization to MDMA was highest 2 weeks after the discontinuation of MDMA treatment. This additional increase in sensitivity was prevented in animals pretreated with DHβE or VAR. At this time, MDMA-treated mice showed a significant increase in heteromeric receptors in cortex that was prevented by DHβE and VAR. An involvement of α7 nicotinic receptors in this effect is ruled out. MDMA (10 mg/kg) induced positive CPP that was abolished by DHβE (2 mg/kg) and VAR (2 mg/kg). Moreover, chronic nicotine pretreatment (2 mg/kg, ip, b.i.d., for 14 days) caused MDMA, administered at a low dose (3 mg/kg), to induce CPP, which would otherwise not occur. Finally, present results point out that heteromeric nicotinic receptors are involved in locomotor sensitization and addictive potential induced by MDMA. Thus, varenicline might be a useful drug to treat both tobacco and MDMA abuse at once.
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Affiliation(s)
- Andrés Ciudad-Roberts
- Department of Pharmacology and Therapeutic Chemistry (Pharmacology Section), Institute of Biomedicine (IBUB), University of Barcelona, Barcelona, Spain
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Cognitive stimulation during lifetime and in the aged phase improved spatial memory, and altered neuroplasticity and cholinergic markers of mice. Exp Gerontol 2013; 48:831-8. [PMID: 23707230 DOI: 10.1016/j.exger.2013.05.055] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2013] [Revised: 05/14/2013] [Accepted: 05/15/2013] [Indexed: 11/22/2022]
Abstract
In the central nervous system, the degree of decline in memory retrieval along the aging process depends on the quantity and quality of the stimuli received during lifetime. The cholinergic system modulates long-term potentiation and, therefore, memory processing. This study evaluated the spatial memory, the synaptic plasticity and the density of cholinergic markers in the hippocampi of mice submitted to cognitive stimulation during lifetime or during their aged phase. Male C57Bl/6 mice (2 months old) were exposed to enriched environment during 15 months (EE-15). An age-matched group was left in standard cages during the same period (SC-15). Spatial memory was evaluated using the Barnes maze at 2, 5, 11 and 17 months of age. At the 17-month-old time point, EE-15 mice showed better performance in the spatial memory task (P<0.05), when compared to C-15 mice. Other two groups of mice were left in regular cages until the age of 15 months, and then one of the groups was transferred to an enriched environment for two months (EE-2). The other group was kept in regular cages (C-2). After two months of stimulation, EE-2 showed a significant increase in spatial memory (P<0.01). At the end, brains were extracted and kept at -80°C. Slices were obtained from one hemisphere in a cryostat (20 μm, -18°C) and thaw-mounted on gelatin coated slides. Synaptic densities, cellular bodies, BDNF densities and α4β2 nicotinic cholinergic receptors (nAChR) were evaluated by immunohistochemistry. Autoradiography for α7 nAChR was conducted using [(125)I]-α-bungarotoxin. The other half of the brains was used for Western blotting analysis of choline acetyltransferase (ChAT) density. There was no difference in synaptophysin or MAP-2 densities, but BDNF was increased in some hippocampal areas of EE-15 and EE-2, in comparison to control groups. In the same way, increases in ChAT and α7 densities, but not in α4β2, were observed. Both cognitive stimuli during lifetime or during the aged phase improved spatial memory of mice. No difference in structural plasticity was observed, but the maintenance of memory can be due to improvement in long-term potentiation functionality in the hippocampus, modulated, at least, by BDNF and the cholinergic system.
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Mazurov AA, Kombo DC, Akireddy S, Murthy S, Hauser TA, Jordan KG, Gatto GJ, Yohannes D. Novel nicotinic acetylcholine receptor agonists containing carbonyl moiety as a hydrogen bond acceptor. Bioorg Med Chem Lett 2013; 23:3927-34. [PMID: 23692872 DOI: 10.1016/j.bmcl.2013.04.058] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2013] [Revised: 04/14/2013] [Accepted: 04/22/2013] [Indexed: 11/16/2022]
Abstract
A novel series of α4β2 nAChR agonists lacking common pyridine or its bioisosteric heterocycle have been disclosed. Essential pharmacophoric elements of the series are exocyclic carbonyl moiety as a hydrogen bond acceptor and secondary amino group within diaza- or azabicyclic scaffold. Computer modeling studies suggested that molecular shape of the ligand also contributes to promotion of agonism. Proof of concept for improving working memory performance in a novel object recognition task has been demonstrated on a representative of the series, 3-propionyl-3,7-diazabicyclo[3.3.0]octane (34).
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Affiliation(s)
- Anatoly A Mazurov
- Targacept, Inc., 100 North Main Street, Winston-Salem, NC 27101, USA.
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Quik M, Campos C, Bordia T, Strachan JP, Zhang J, McIntosh JM, Letchworth S, Jordan K. α4β2 Nicotinic receptors play a role in the nAChR-mediated decline in L-dopa-induced dyskinesias in parkinsonian rats. Neuropharmacology 2013; 71:191-203. [PMID: 23583932 DOI: 10.1016/j.neuropharm.2013.03.038] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Revised: 03/25/2013] [Accepted: 03/28/2013] [Indexed: 12/26/2022]
Abstract
L-Dopa-induced dyskinesias are a serious long-term side effect of dopamine replacement therapy for Parkinson's disease for which there are few treatment options. Our previous studies showed that nicotine decreased l-dopa-induced abnormal involuntary movements (AIMs). Subsequent work with knockout mice demonstrated that α6β2* nicotinic receptors (nAChRs) play a key role. The present experiments were done to determine if α4β2* nAChRs are also involved in l-dopa-induced dyskinesias. To approach this, we took advantage of the finding that α6β2* nAChRs are predominantly present on striatal dopaminergic nerve terminals, while a significant population of α4β2* nAChRs are located on other neurons. Thus, a severe dopaminergic lesion would cause a major loss in α6β2*, but not α4β2* nAChRs. Experiments were therefore done in which rats were unilaterally lesioned with 6-hydroxydopamine, at a dose that led to severe nigrostriatal damage. The dopamine transporter, a dopamine nerve terminal marker, was decreased by >99%. This lesion also decreased striatal α6β2* nAChRs by 97%, while α4β2* nAChRs were reduced by only 12% compared to control. A series of β2* nAChR compounds, including TC-2696, TI-10165, TC-8831, TC-10600 and sazetidine reduced l-dopa-induced AIMs in these rats by 23-32%. TC-2696, TI-10165, TC-8831 were also tested for parkinsonism, with no effect on this behavior. Tolerance did not develop with up to 3 months of treatment. Since α4α5β2 nAChRs are also predominantly on striatal dopamine terminals, these data suggest that drugs targeting α4β2 nAChRs may reduce l-dopa-induced dyskinesias in late stage Parkinson's disease.
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Affiliation(s)
- Maryka Quik
- Center for Health Sciences, SRI International, 333 Ravenswood Ave., Menlo Park, CA 94025, USA.
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43
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Horti AG, Ravert HT, Gao Y, Holt DP, Bunnelle WH, Schrimpf MR, Li T, Ji J, Valentine H, Scheffel U, Kuwabara H, Wong DF, Dannals RF. Synthesis and evaluation of new radioligands [(11)C]A-833834 and [(11)C]A-752274 for positron-emission tomography of α7-nicotinic acetylcholine receptors. Nucl Med Biol 2013; 40:395-402. [PMID: 23294899 PMCID: PMC3596482 DOI: 10.1016/j.nucmedbio.2012.11.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2012] [Revised: 10/31/2012] [Accepted: 11/20/2012] [Indexed: 01/31/2023]
Abstract
INTRODUCTION α7-nicotinic acetylcholine receptor (α7-nAChR) is one of the major neuronal nAChR subtypes. α7-nAChR is involved in variety of neuronal processes and disorders including schizophrenia and Alzheimer's disease. A number of α7-nAChR PET radioligands have been developed, but a quality radiotracer remains to be discovered. METHODS High binding affinity α7-nAChR ligands A-833834 and A-752274 were radiolabeled with (11)C. Baseline and blockade biodistribution studies in the mouse brain of [(11)C]A-833834 (5-(6-(5-[(11)C]methylhexahydropyrrolo[3,4-c]pyrrol-2(1H)-yl)pyridazin-3-yl)-1H-indole) and [(11)C]A-752274 (2-(6-[(11)C]methyl-3,6-diazabicyclo[3.2.0]heptan-3-yl)-7-(6-methyl-3,6-diazabicyclo[3.2.0]heptan-3-yl)-9H-fluoren-9-one) were performed. [(11)C]A-752274 was evaluated in a baseline baboon PET study. RESULTS [(11)C]A-833834 and [(11)C]A-752274 were synthesized by radiomethylation of corresponding des-methyl precursors. The radioligands were prepared with radiochemical yield of 12%-32%, high specific radioactivity (330-403GBq/μmol) and radiochemical purity>95%. Dissection studies with [(11)C]A-833834 demonstrated low specific α7-nAChR binding in the mouse brain. [(11)C]A-752274 specifically (~50%) labeled α7-nAChR in the mouse thalamus. However, [(11)CA-752274 exhibited low brain uptake in baboon (%SUV<100). CONCLUSION Two novel α7-nAChR ligands radioligands were synthesized and studied in animals. Specific binding of [(11)C]A-833834 in the mouse brain is low due to the insufficient binding affinity of the radioligand. The very high binding affinity [(11)C]A-752274 exhibited good specific binding in the α7-nAChR-rich mouse brain regions. The low uptake of [(11)C]A-752274 in the baboon brain is due to its high hydrophilicity, rapid metabolism or other properties. Future development of α7-nAChR PET radioligands will be based on compounds with high binding affinities and good blood-brain barrier permeability.
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Affiliation(s)
- Andrew G Horti
- Division of Nuclear Medicine, Department of Radiology, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA.
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Dunlop J, Peri R, Terstappen GC, Bowlby M. Functional screening of α7 nicotinic receptor ligands. Expert Opin Drug Discov 2013; 3:623-8. [PMID: 23506144 DOI: 10.1517/17460441.3.6.623] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND The α7 nicotinic acetylcholine receptor, a ligand-gated ion channel, is an attractive drug discovery target in schizophrenia and Alzheimer's disease. OBJECTIVE We have evaluated the various approaches to discovering ligands targeting the α7 nicotinic receptor to define the current paradigm driving drug discovery efforts in this area. METHODS Assays using functional read-outs as a consequence of α7 nicotinic receptor activation have been reviewed. CONCLUSION Functional assays using fluorescence-based optical methods in combination with direct electrophysiological recordings of channel function currently provide an integrated approach to the discovery of α7 nicotinic receptor targeted ligands.
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Affiliation(s)
- John Dunlop
- Neuroscience Discovery Research, Wyeth Research, CN-8000, Princeton, NJ 08543, USA +1 732 274 4193 ; +1 732 274 4755 ;
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45
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Puinean AM, Lansdell SJ, Collins T, Bielza P, Millar NS. A nicotinic acetylcholine receptor transmembrane point mutation (G275E) associated with resistance to spinosad in Frankliniella occidentalis. J Neurochem 2013; 124:590-601. [PMID: 23016960 PMCID: PMC3644170 DOI: 10.1111/jnc.12029] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2012] [Accepted: 09/24/2012] [Indexed: 12/20/2022]
Abstract
High levels of resistance to spinosad, a macrocyclic lactone insecticide, have been reported previously in western flower thrips, Frankliniella occidentalis, an economically important insect pest of vegetables, fruit and ornamental crops. We have cloned the nicotinic acetylcholine receptor (nAChR) α6 subunit from F. occidentalis (Foα6) and compared the nucleotide sequence of Foα6 from susceptible and spinosad-resistant insect populations (MLFOM and R1S respectively). A single nucleotide change has been identified in Foα6, resulting in the replacement of a glycine (G) residue in susceptible insects with a glutamic acid (E) in resistant insects. The resistance-associated mutation (G275E) is predicted to lie at the top of the third α-helical transmembrane domain of Foα6. Although there is no direct evidence identifying the location of the spinosad binding site, the analogous amino acid in the C. elegans glutamate-gated chloride channel lies in close proximity (4.4 Å) to the known binding site of ivermectin, another macrocyclic lactone pesticide. The functional consequences of the resistance-associated mutation have been examined in the human nAChR α7 subunit. Introduction of an analogous (A272E) mutation in α7 abolishes the modulatory effects of spinosad whilst having no significant effect upon activation by acetylcholine, consistent with spinosad having an allosteric mechanism of action.
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Affiliation(s)
- Alin M Puinean
- Department of Neuroscience, Physiology & Pharmacology, University College London, London, UK
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46
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Ferchmin PA, Pérez D, Castro Alvarez W, Penzo MA, Maldonado HM, Eterovic VA. γ-Aminobutyric acid type A receptor inhibition triggers a nicotinic neuroprotective mechanism. J Neurosci Res 2012; 91:416-25. [PMID: 23280428 DOI: 10.1002/jnr.23155] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2012] [Revised: 08/09/2012] [Accepted: 09/14/2012] [Indexed: 01/09/2023]
Abstract
Nicotinic acetylcholine receptor (nAChR)-mediated neuroprotection has been implicated in the treatment of neurodegenerative disorders such as Alzheimer's and Parkinson's diseases and hypoxic ischemic events as well as other diseases hallmarked by excitotoxic and apoptotic neuronal death. Several modalities of nicotinic neuroprotection have been reported. However, although this process generally involves α4β2 and α7 subtypes, the underlying mechanisms are largely unknown. Interestingly, both activation and inhibition of α7 nAChRs have been reported to be neuroprotective. We have shown that inhibition of α7 nAChRs protects the function of acute hippocampal slices against excitotoxicity in an α4β2-dependent manner. Neuroprotection was assessed as the prevention of the N-methyl-D-aspartate-dependent loss of the area of population spikes (PSs) in the CA1 area of acute hippocampal slices. Our results support a model in which α7 AChRs control the release of γ-aminobutyric acid (GABA). Blocking either α7 or GABA(A) receptors reduces the inhibitory tone on cholinergic terminals, thereby promoting α4β2 activation, which in turn mediates neuroprotection. These results shed light on how α7 nAChR inhibition can be neuroprotective through a mechanism mediated by activation of α4β2 nAChRs.
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Affiliation(s)
- P A Ferchmin
- School of Medicine, Universidad Central del Caribe, Bayamón, Puerto Rico.
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Pubill D, Garcia-Ratés S, Camarasa J, Escubedo E. 3,4-Methylenedioxy-methamphetamine induces in vivo regional up-regulation of central nicotinic receptors in rats and potentiates the regulatory effects of nicotine on these receptors. Neurotoxicology 2012; 35:41-9. [PMID: 23261423 DOI: 10.1016/j.neuro.2012.11.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2012] [Revised: 11/19/2012] [Accepted: 11/22/2012] [Indexed: 12/01/2022]
Abstract
Nicotine (NIC), the main psychostimulant compound of smoked tobacco, exerts its effects through activation of central nicotinic acetylcholine receptors (nAChR), which become up-regulated after chronic administration. Recent work has demonstrated that the recreational drug 3,4-methylenedioxy-methamphetamine (MDMA) has affinity for nAChR and also induces up-regulation of nAChR in PC 12 cells. Tobacco and MDMA are often consumed together. In the present work we studied the in vivo effect of a classic chronic dosing schedule of MDMA in rats, alone or combined with a chronic schedule of NIC, on the density of nAChR and on serotonin reuptake transporters. MDMA induced significant decreases in [(3)H]paroxetine binding in the cortex and hippocampus measured 24h after the last dose and these decreases were not modified by the association with NIC. In the prefrontal cortex, NIC and MDMA each induced significant increases in [(3)H]epibatidine binding (29.5 and 34.6%, respectively) with respect to saline-treated rats, and these increases were significantly potentiated (up to 72.1%) when the two drugs were associated. Also in this area, [(3)H]methyllycaconitine binding was increased a 42.1% with NIC+MDMA but not when they were given alone. In the hippocampus, MDMA potentiated the α7 regulatory effects of NIC (raising a 25.5% increase to 52.5%) but alone was devoid of effect. MDMA had no effect on heteromeric nAChR in striatum and a coronal section of the midbrain containing superior colliculi, geniculate nuclei, substantia nigra and ventral tegmental area. Specific immunoprecipitation of solubilised receptors suggests that the up-regulated heteromeric nAChRs contain α4 and β2 subunits. Western blots with specific α4 and α7 antibodies showed no significant differences between the groups, indicating that, as reported for nicotine, up-regulation caused by MDMA is due to post-translational events rather than increased receptor synthesis.
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Affiliation(s)
- David Pubill
- Unitat de Farmacologia i Farmacognòsia, Facultat de Farmàcia, Nucli Universitari de Pedralbes, Universitat de Barcelona, Institut de Biomedicina de la UB (IBUB), 08028 Barcelona, Spain.
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48
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Mazurov AA, Kombo DC, Hauser TA, Miao L, Dull G, Genus JF, Fedorov NB, Benson L, Sidach S, Xiao Y, Hammond PS, James JW, Miller CH, Yohannes D. Discovery of (2S,3R)-N-[2-(Pyridin-3-ylmethyl)-1-azabicyclo[2.2.2]oct-3-yl]benzo[b]furan-2-carboxamide (TC-5619), a Selective α7 Nicotinic Acetylcholine Receptor Agonist, for the Treatment of Cognitive Disorders. J Med Chem 2012; 55:9793-809. [DOI: 10.1021/jm301048a] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Anatoly A. Mazurov
- Targacept, Inc., Winston-Salem, North
Carolina 27101-4165,
United States
| | - David C. Kombo
- Targacept, Inc., Winston-Salem, North
Carolina 27101-4165,
United States
| | - Terry A. Hauser
- Targacept, Inc., Winston-Salem, North
Carolina 27101-4165,
United States
| | - Lan Miao
- Targacept, Inc., Winston-Salem, North
Carolina 27101-4165,
United States
| | - Gary Dull
- Targacept, Inc., Winston-Salem, North
Carolina 27101-4165,
United States
| | - John F. Genus
- Targacept, Inc., Winston-Salem, North
Carolina 27101-4165,
United States
| | - Nikolai B. Fedorov
- Targacept, Inc., Winston-Salem, North
Carolina 27101-4165,
United States
| | - Lisa Benson
- Targacept, Inc., Winston-Salem, North
Carolina 27101-4165,
United States
| | - Serguei Sidach
- Targacept, Inc., Winston-Salem, North
Carolina 27101-4165,
United States
| | - Yunde Xiao
- Targacept, Inc., Winston-Salem, North
Carolina 27101-4165,
United States
| | - Philip S. Hammond
- Targacept, Inc., Winston-Salem, North
Carolina 27101-4165,
United States
| | - John W. James
- Targacept, Inc., Winston-Salem, North
Carolina 27101-4165,
United States
| | - Craig H. Miller
- Targacept, Inc., Winston-Salem, North
Carolina 27101-4165,
United States
| | - Daniel Yohannes
- Targacept, Inc., Winston-Salem, North
Carolina 27101-4165,
United States
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49
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Xiao Y, Hammond PS, Mazurov AA, Yohannes D. Multiple Interaction Regions in the Orthosteric Ligand Binding Domain of the α7 Neuronal Nicotinic Acetylcholine Receptor. J Chem Inf Model 2012; 52:3064-73. [DOI: 10.1021/ci3001953] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Yunde Xiao
- Targacept, Inc., 200 East
First Street, Suite 300, Winston-Salem, North Carolina 27101, United
States
| | - Philip S. Hammond
- Targacept, Inc., 200 East
First Street, Suite 300, Winston-Salem, North Carolina 27101, United
States
| | - Anatoly A. Mazurov
- Targacept, Inc., 200 East
First Street, Suite 300, Winston-Salem, North Carolina 27101, United
States
| | - Daniel Yohannes
- Targacept, Inc., 200 East
First Street, Suite 300, Winston-Salem, North Carolina 27101, United
States
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50
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Ghedini PC, Avellar MCW, De Lima TCM, Lima-Landman MTR, Lapa AJ, Souccar C. Quantitative changes of nicotinic receptors in the hippocampus of dystrophin-deficient mice. Brain Res 2012; 1483:96-104. [PMID: 22995368 DOI: 10.1016/j.brainres.2012.09.021] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2012] [Revised: 09/09/2012] [Accepted: 09/10/2012] [Indexed: 10/27/2022]
Abstract
Lack of dystrophin in Duchenne muscle dystrophy (DMD) and in the mutant mdx mouse results in progressive muscle degeneration, structural changes at the neuromuscular junction, and destabilization of the nicotinic acetylcholine receptors (nAChRs). One-third of DMD patients also present non-progressive cognitive impairments. Considering the role of the cholinergic system in cognitive functions, the number of nAChR binding sites and the mRNA levels of α4, β2, and α7 subunits were determined in brain regions normally enriched in dystrophin (cortex, hippocampus and cerebellum) of mdx mice using specific ligands and reverse-transcription polymerase chain reaction assays, respectively. Membrane preparations of these brain regions were obtained from male control and mdx mice at 4 and 12 months of age. The number of [³H]-cytisine (α4β2) and [¹²⁵I]-α-bungarotoxin ([¹²⁵I]-αBGT, α7) binding sites in the cortex and cerebellum was not altered with age or among age-matched control and mdx mice. A significant reduction in [³H]-cytisine (48%) and [¹²⁵I]-αBGT (37%) binding sites was detected in the hippocampus of mdx mice at 12 months of age. When compared with the age-matched control groups, the mdx mice did not have significantly altered [³H]-cytisine binding in the hippocampus, but [¹²⁵I]-αBGT binding in the same brain region was 52% higher at 4 months and 20% lower at 12 months. mRNA transcripts for the nAChR α4, β2, and α7 subunits were not significantly altered in the same brain regions of all animal groups. These results suggest a potential alteration of the nicotinic cholinergic function in the hippocampus of dystrophin-deficient mice, which might contribute to the impairments in cognitive functions, such as learning and memory, that have been reported in the dystrophic murine model and DMD patients.
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Affiliation(s)
- Paulo César Ghedini
- Department of Pharmacology, Section of Natural Products, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, SP, Brazil
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