1
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Sanders VR, Millar NS. Potentiation and allosteric agonist activation of α7 nicotinic acetylcholine receptors: binding sites and hypotheses. Pharmacol Res 2023; 191:106759. [PMID: 37023990 DOI: 10.1016/j.phrs.2023.106759] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 03/27/2023] [Accepted: 03/30/2023] [Indexed: 04/07/2023]
Abstract
Considerable progress has been made in recent years towards the identification and characterisation of novel subtype-selective modulators of nicotinic acetylcholine receptors (nAChRs). In particular, this has focussed on modulators of α7 nAChRs, a nAChR subtype that has been identified as a target for drug discovery in connection with a range of potential therapeutic applications. This review focusses upon α7-selective modulators that bind to receptor sites other than the extracellular 'orthosteric' agonist binding site for the endogenous agonist acetylcholine (ACh). Such compounds include those that are able to potentiate responses evoked by orthosteric agonists such as ACh (positive allosteric modulators; PAMs) and those that are able to activate α7 nAChRs by direct allosteric activation in the absence of an orthosteric agonist (allosteric agonists or 'ago-PAMs'). There has been considerable debate about the mechanism of action of α7-selective PAMs and allosteric agonists, much of which has centred around identifying the location of their binding sites on α7 nAChRs. Based on a variety of experimental evidence, including recent structural data, there is now clear evidence indicating that at least some α7-selective PAMs bind to an inter-subunit site located in the transmembrane domain. In contrast, there are differing hypotheses about the site or sites at which allosteric agonists bind to α7 nAChRs. It will be argued that the available evidence supports the conclusion that direct allosteric activation by allosteric agonists/ago-PAMs occurs via the same inter-subunit transmembrane site that has been identified for several α7-selective PAMs.
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Affiliation(s)
- Victoria R Sanders
- Division of Biosciences, University College London, London WC1E 6BT, United Kingdom
| | - Neil S Millar
- Division of Biosciences, University College London, London WC1E 6BT, United Kingdom.
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2
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Perlett L, Smith EE. Treatment of Vascular and Neurodegenerative Forms of Cognitive Impairment and Dementias. Clin Geriatr Med 2023; 39:135-149. [PMID: 36404026 DOI: 10.1016/j.cger.2022.07.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Ideally, dementia care should be provided by a collaborative team. Eligible patients should be treated with the cognitive-enhancing medications, the cholinesterase inhibitors and memantine. For most of the common causes of dementia, there are no disease-modifying medications, with the exception that vascular dementia can be prevented by treating vascular risk factors to prevent stroke. There is hope that Alzheimer disease can be treated by using monoclonal antibodies that target amyloid beta, although more trials are needed. Holistic, patient-centered care can enhance quality and extend the time that the patient can live safely in the community.
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Affiliation(s)
- Landon Perlett
- Department of Clinical Neurosciences, University of Calgary, Calgary, Alberta, Canada
| | - Eric E Smith
- Department of Clinical Neurosciences, University of Calgary, Calgary, Alberta, Canada.
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3
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Ray SK, Mukherjee S. Neuropharmacology of Alcohol Addiction with Special Emphasis on Proteomic Approaches for Identification of Novel Therapeutic Targets. Curr Neuropharmacol 2023; 21:119-132. [PMID: 35959616 PMCID: PMC10193758 DOI: 10.2174/1570159x20666220811092906] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 07/01/2022] [Accepted: 07/10/2022] [Indexed: 02/04/2023] Open
Abstract
Alcohol is a generic pharmacological agent with only a few recognized primary targets. Nmethyl- D-aspartate, gamma-aminobutyric acid, glycine, 5-hydroxytryptamine 3 (serotonin), nicotinic acetylcholine receptors, and L-type Ca2+ channels and G-protein-activated inwardly rectifying K channels are all involved. Following the first hit of alcohol on specific brain targets, the second wave of indirect effects on various neurotransmitter/neuropeptide systems begins, leading to the typical acute behavioral effects of alcohol, which range from disinhibition to sedation and even hypnosis as alcohol concentrations rise. Recent research has revealed that gene regulation is significantly more complex than previously thought and does not fully explain changes in protein levels. As a result, studying the proteome directly, which differs from the genome/transcriptome in terms of complexity and dynamicity, has provided unique insights into extraordinary advances in proteomic techniques that have changed the way we can analyze the composition, regulation, and function of protein complexes and pathways underlying altered neurobiological conditions. Neuroproteomics has the potential to revolutionize alcohol research by allowing researchers to gain a better knowledge of how alcohol impacts protein structure, function, connections, and networks on a global scale. The amount of information collected from these breakthroughs can aid in identifying valuable biomarkers for early detection and improved prognosis of an alcohol use disorder and future pharmaceutical targets for the treatment of alcoholism.
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Affiliation(s)
- Suman Kumar Ray
- Independent Researcher, Bhopal, Madhya Pradesh 462020, India
| | - Sukhes Mukherjee
- Department of Biochemistry, All India Institute of Medical Science, Bhopal, Madhya Pradesh 462020, India
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4
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Shegani A, Kealey S, Luzi F, Basagni F, Machado JDM, Ekici SD, Ferocino A, Gee AD, Bongarzone S. Radiosynthesis, Preclinical, and Clinical Positron Emission Tomography Studies of Carbon-11 Labeled Endogenous and Natural Exogenous Compounds. Chem Rev 2022; 123:105-229. [PMID: 36399832 PMCID: PMC9837829 DOI: 10.1021/acs.chemrev.2c00398] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The presence of positron emission tomography (PET) centers at most major hospitals worldwide, along with the improvement of PET scanner sensitivity and the introduction of total body PET systems, has increased the interest in the PET tracer development using the short-lived radionuclides carbon-11. In the last few decades, methodological improvements and fully automated modules have allowed the development of carbon-11 tracers for clinical use. Radiolabeling natural compounds with carbon-11 by substituting one of the backbone carbons with the radionuclide has provided important information on the biochemistry of the authentic compounds and increased the understanding of their in vivo behavior in healthy and diseased states. The number of endogenous and natural compounds essential for human life is staggering, ranging from simple alcohols to vitamins and peptides. This review collates all the carbon-11 radiolabeled endogenous and natural exogenous compounds synthesised to date, including essential information on their radiochemistry methodologies and preclinical and clinical studies in healthy subjects.
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Affiliation(s)
- Antonio Shegani
- School
of Biomedical Engineering & Imaging Sciences, King’s College London, King’s Health Partners, St Thomas’ Hospital, London SE1 7EH, United Kingdom
| | - Steven Kealey
- School
of Biomedical Engineering & Imaging Sciences, King’s College London, King’s Health Partners, St Thomas’ Hospital, London SE1 7EH, United Kingdom
| | - Federico Luzi
- School
of Biomedical Engineering & Imaging Sciences, King’s College London, King’s Health Partners, St Thomas’ Hospital, London SE1 7EH, United Kingdom
| | - Filippo Basagni
- Department
of Pharmacy and Biotechnology, Alma Mater
Studiorum−University of Bologna, via Belmeloro 6, 40126 Bologna, Italy
| | - Joana do Mar Machado
- School
of Biomedical Engineering & Imaging Sciences, King’s College London, King’s Health Partners, St Thomas’ Hospital, London SE1 7EH, United Kingdom
| | - Sevban Doğan Ekici
- School
of Biomedical Engineering & Imaging Sciences, King’s College London, King’s Health Partners, St Thomas’ Hospital, London SE1 7EH, United Kingdom
| | - Alessandra Ferocino
- Institute
of Organic Synthesis and Photoreactivity, Italian National Research Council, via Piero Gobetti 101, 40129 Bologna, Italy
| | - Antony D. Gee
- School
of Biomedical Engineering & Imaging Sciences, King’s College London, King’s Health Partners, St Thomas’ Hospital, London SE1 7EH, United Kingdom,A.G.: email,
| | - Salvatore Bongarzone
- School
of Biomedical Engineering & Imaging Sciences, King’s College London, King’s Health Partners, St Thomas’ Hospital, London SE1 7EH, United Kingdom,S.B.:
email,
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5
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Ashraf GM, Gupta DD, Alam MZ, Baeesa SS, Alghamdi BS, Anwar F, Alqurashi TMA, Al Abdulmonem W, Alyousef MA, Alhumaydhi FA, Shamsi A. Unravelling Binding of Human Serum Albumin with Galantamine: Spectroscopic, Calorimetric, and Computational Approaches. ACS OMEGA 2022; 7:34370-34377. [PMID: 36188253 PMCID: PMC9521020 DOI: 10.1021/acsomega.2c04004] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Accepted: 08/10/2022] [Indexed: 06/16/2023]
Abstract
Human serum albumin (HSA), an abundant plasma protein, binds to various ligands, acting as a transporter for numerous endogenous and exogenous substances. Galantamine (GAL), an alkaloid, treats cognitive decline in mild to moderate Alzheimer's disease and other memory impairments. A vital step in pharmacological profiling involves the interaction of plasma protein with the drugs, and this serves as an essential platform for pharmaceutical industry advancements. This study is carried out to understand the binding mechanism of GAL with HSA using computational and experimental approaches. Molecular docking revealed that GAL preferentially occupies Sudlow's site I, i.e., binds to subdomain IIIA. The results unveiled that GAL binding does not induce any conformational change in HSA and hence does not compromise the functionality of HSA. Molecular dynamics simulation (250 ns) deciphered the stability of the HSA-GAL complex. We performed the fluorescence binding and isothermal titration calorimetry (ITC) to analyze the actual binding of GAL with HSA. The results suggested that GAL binds to HSA with a significant binding affinity. ITC measurements also delineated thermodynamic parameters associated with the binding of GAL to HSA. Altogether, the present study deciphers the binding mechanism of GAL with HSA.
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Affiliation(s)
- Ghulam Md Ashraf
- Pre-Clinical
Research Unit, King Fahd Medical Research Center, King Abdulaziz University, Jeddah 21589, Saudi Arabia
- Department
of Medical Laboratory Sciences, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah 21589, Saudi Arabia
| | - Debarati Das Gupta
- College
of Pharmacy, University of Michigan, 428 Church Street, Ann Arbor, Michigan 48109, United States
| | - Mohammad Zubair Alam
- Pre-Clinical
Research Unit, King Fahd Medical Research Center, King Abdulaziz University, Jeddah 21589, Saudi Arabia
- Department
of Medical Laboratory Sciences, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah 21589, Saudi Arabia
| | - Saleh Salem Baeesa
- Division
of Neurosurgery, College of Medicine, King
Abdulaziz University, Jeddah 21589, Saudi Arabia
| | - Badrah S. Alghamdi
- Pre-Clinical
Research Unit, King Fahd Medical Research Center, King Abdulaziz University, Jeddah 21589, Saudi Arabia
- Department
of Physiology, Faculty of Medicine, King
Abdulaziz University, Jeddah 21589, Saudi Arabia
- The
Neuroscience
Research Unit, Faculty of Medicine, King
Abdulaziz University, Jeddah 21589, Saudi Arabia
| | - Firoz Anwar
- Department
of Biochemistry, Faculty of Science, King
Abdulaziz University, Jeddah 21589, Saudi Arabia
| | - Thamer M. A. Alqurashi
- Department
of Pharmacology, Faculty of Medicine, King
Abdul-Aziz University, Rabigh 25724, Saudi Arabia
| | - Waleed Al Abdulmonem
- Department
of Pathology, College of Medicine, Qassim
University, Buraydah 52571, Saudi Arabia
| | - Mohammed A. Alyousef
- Division of Neurosurgery, King
Abdulaziz
University Hospital, Jeddah 21589, Saudi Arabia
| | - Fahad A. Alhumaydhi
- Department of Medical Laboratories, College of Applied
Medical Sciences, Qassim University, Buraydah 52571, Saudi Arabia
| | - Anas Shamsi
- Centre for Interdisciplinary Research in
Basic Sciences, Jamia Millia Islamia, Jamia Nagar, New Delhi 110025, India
- Centre of Medical and Bio-Allied Health Sciences Research, Ajman University, P.O.
Box Number 346, Ajman, United Arab Emirates
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6
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Weber LA, Tomiello S, Schöbi D, Wellstein KV, Mueller D, Iglesias S, Stephan KE. Auditory mismatch responses are differentially sensitive to changes in muscarinic acetylcholine versus dopamine receptor function. eLife 2022; 11:74835. [PMID: 35502897 PMCID: PMC9098218 DOI: 10.7554/elife.74835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Accepted: 04/26/2022] [Indexed: 11/13/2022] Open
Abstract
The auditory mismatch negativity (MMN) has been proposed as a biomarker of NMDA receptor (NMDAR) dysfunction in schizophrenia. Such dysfunction may be caused by aberrant interactions of different neuromodulators with NMDARs, which could explain clinical heterogeneity among patients. In two studies (N = 81 each), we used a double-blind placebo-controlled between-subject design to systematically test whether auditory mismatch responses under varying levels of environmental stability are sensitive to diminishing and enhancing cholinergic vs. dopaminergic function. We found a significant drug × mismatch interaction: while the muscarinic acetylcholine receptor antagonist biperiden delayed and topographically shifted mismatch responses, particularly during high stability, this effect could not be detected for amisulpride, a dopamine D2/D3 receptor antagonist. Neither galantamine nor levodopa, which elevate acetylcholine and dopamine levels, respectively, exerted significant effects on MMN. This differential MMN sensitivity to muscarinic versus dopaminergic receptor function may prove useful for developing tests that predict individual treatment responses in schizophrenia.
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Affiliation(s)
- Lilian Aline Weber
- Translational Neuroimaging Unit (TNU), Institute for Biomedical EngineeringInstitute for Biomedical Engineering, University of Zurich, Zurich, Switzerland
| | - Sara Tomiello
- Translational Neuroimaging Unit (TNU), Institute for Biomedical Engineering, University of Zurich, Zurich, Switzerland
| | - Dario Schöbi
- Translational Neuroimaging Unit (TNU), Institute for Biomedical Engineering, University of Zurich, Zurich, Switzerland
| | - Katharina V Wellstein
- Translational Neuroimaging Unit (TNU), Institute for Biomedical Engineering, University of Zurich, Zurich, Switzerland
| | - Daniel Mueller
- Institute for Clinical Chemistry, University Hospital of Zurich, Zurich, Switzerland
| | - Sandra Iglesias
- Translational Neuroimaging Unit (TNU), Institute for Biomedical Engineering, University of Zurich, Zurich, Switzerland
| | - Klaas Enno Stephan
- Translational Neuroimaging Unit (TNU), Institute for Biomedical Engineering, University of Zurich, Zurich, Switzerland
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7
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Argade MD, DeCristofano L, Bhattarai N, Schulte MK, Dukat M. Evaluation of galantamine and deconstructed analogs as α7 nAChR and AChE ligands. RESULTS IN CHEMISTRY 2022. [DOI: 10.1016/j.rechem.2022.100286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
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8
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Zhu X, Zhou Y, Yuan G, Shi J, Shi S, Zhang L, Chai R, Du Y, Duan C, Hu Y. Bibliometric analysis of nicotinic acetylcholine receptors channel research (2000-2020). Channels (Austin) 2021; 15:298-309. [PMID: 33615989 PMCID: PMC7901545 DOI: 10.1080/19336950.2021.1882113] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2021] [Revised: 01/20/2021] [Accepted: 01/20/2021] [Indexed: 11/15/2022] Open
Abstract
To explore the research status, hotspots, and trends in research on nicotinic acetylcholine receptor (nAChR) channel. The Web of Science core collection database from 2000 to 2020 was used as the data source. The visual analysis software VOSviewer1.6.16 and Citespace5.7 R3 were used to visualize the studies of the nAChR channel. The national/institutional distribution, journal distribution, authors, and related research were discussed. A total of 5,794 articles were obtained. The USA and the Utah System of Higher Education were the most productive country and institution for nAChR channel research. Journal of Biological Chemistry was the most productive journal (212) and the most productive researcher was McIntosh, J. Michael. The first highly co-cited article was "Refined structure of the nicotinic acetylcholine receptor at 4A resolution." The most researched area was neurosciences neurology. The hot spots of nAChR channel research were "subunit and structure of nAChR," "activation/agonist of nAChR channel," and "Changes in nAChRs With Alzheimer's Disease." The top three research frontiers of nAChR channel research were "neuropathic pain," "neuroinflammation," and "α7 nACHR." The study provides a perspective to visualize and analyze hotspots and emerging trends in the nAChR channel.
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Affiliation(s)
- Xueping Zhu
- Cardiovascular Department, Guanganmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Yan Zhou
- Cardiovascular Department, Graduate School of Beijing University of Chinese Medicine, Beijing, China
| | - Guozhen Yuan
- Cardiovascular Department, Guanganmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Jingjing Shi
- Cardiovascular Department, Guanganmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Shuai Shi
- Cardiovascular Department, Guanganmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Limei Zhang
- Cardiovascular Department, Guanganmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Ruoning Chai
- Cardiovascular Department, Guanganmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Yihang Du
- Cardiovascular Department, Guanganmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Chenglin Duan
- Cardiovascular Department, Graduate School of Beijing University of Chinese Medicine, Beijing, China
| | - Yuanhui Hu
- Cardiovascular Department, Guanganmen Hospital, China Academy of Chinese Medical Sciences, Beijing, China
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9
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Ahring PK, Liao VWY, Gardella E, Johannesen KM, Krey I, Selmer KK, Stadheim BF, Davis H, Peinhardt C, Koko M, Coorg RK, Syrbe S, Bertsche A, Santiago-Sim T, Diemer T, Fenger CD, Platzer K, Eichler EE, Lerche H, Lemke JR, Chebib M, Møller RS. Gain-of-function variants in GABRD reveal a novel pathway for neurodevelopmental disorders and epilepsy. Brain 2021; 145:1299-1309. [PMID: 34633442 DOI: 10.1093/brain/awab391] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 09/15/2021] [Accepted: 09/20/2021] [Indexed: 11/14/2022] Open
Abstract
A potential link between GABRD encoding the δ subunit of extrasynaptic GABAA receptors and neurodevelopmental disorders has largely been disregarded due to conflicting conclusions from early studies. However, we identified seven heterozygous missense GABRD variants in 10 patients with neurodevelopmental disorders and generalized epilepsy. One variant occurred in two sibs of healthy parents with presumed somatic mosaicism, another segregated with the disease in three affected family members, and the remaining five occurred de novo in sporadic patients. Electrophysiological measurements were used to determine the functional consequence of the seven missense δ subunit variants in receptor combinations of α1β3δ and α4β2δ GABAA receptors. This was accompanied by analysis of electro-clinical phenotypes of the affected individuals. We determined that five of the seven variants caused altered function of the resulting α1β3δ and α4β2δ GABAA receptors. Surprisingly, four of the five variants led to gain-of-function effects whereas one led to a loss-of-function effect. The stark differences between the gain-of-function and loss-of function effects were mirrored by the clinical phenotypes. Six patients with gain-of-function variants shared common phenotypes: neurodevelopmental disorders with generalized epilepsy, behavioral issues, and various degrees of intellectual disability. Six patients with gain-of-function variants shared common phenotypes: neurodevelopmental disorders with behavioral issues, various degrees of intellectual disability, generalized epilepsy with atypical absences and generalized myoclonic and/or bilateral tonic-clonic seizures. The EEG showed qualitative analogies among the different gain-of-function variant carriers consisting of focal slowing in the occipital regions often preceding irregular generalized epileptiform discharges, with frontal predominance. In contrast, the one patient carrying a loss-of-function variant had normal intelligence, no seizure history but has a diagnosis of autism spectrum disorder and suffering from elevated internalizing psychiatric symptoms. We hypothesize that increase in tonic GABA-evoked current levels mediated by δ-containing extrasynaptic GABAA receptors lead to abnormal neurotransmission, which represent a novel mechanism for severe neurodevelopmental disorders. In support of this, the electro-clinical findings for the gain-of-function GABRD variants resemble the phenotypic spectrum reported in patients with missense SLC6A1 (GABA uptake transporter) variants. This also indicates that the phenomenon of extrasynaptic receptor over-activity is observed in a broader range of patients with neurodevelopmental disorders, since SLC6A1 loss-of-function variants also lead to overactive extrasynaptic δ-containing GABAA receptors. These findings have implications when selecting potential treatment options, since a substantial portion of available anti-seizure medication act by enhancing GABAergic function either directly or indirectly, which could exacerbate symptoms in patients with gain-of-function GABRD variants.
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Affiliation(s)
- Philip K Ahring
- Brain and Mind Centre, School of Pharmacy, Faculty of Medicine and Health, The University of Sydney; Sydney, New South Wales, Australia
| | - Vivian W Y Liao
- Brain and Mind Centre, School of Pharmacy, Faculty of Medicine and Health, The University of Sydney; Sydney, New South Wales, Australia
| | - Elena Gardella
- Department of Epilepsy Genetics and Personalized Treatment, The Danish Epilepsy Centre; Dianalund, Denmark.,Department of Regional Health Research, University of Southern Denmark; Odense, Denmark
| | - Katrine M Johannesen
- Department of Epilepsy Genetics and Personalized Treatment, The Danish Epilepsy Centre; Dianalund, Denmark.,Department of Regional Health Research, University of Southern Denmark; Odense, Denmark
| | - Ilona Krey
- Institute of Human Genetics, University of Leipzig Medical Center; Leipzig, Germany
| | - Kaja K Selmer
- National Centre for Rare Epilepsy-Related Disorders, Oslo University Hospital; Oslo, Norway.,Department of Medical Genetics, Oslo University Hospital; Oslo, Norway
| | - Barbro F Stadheim
- Department of Medical Genetics, Oslo University Hospital; Oslo, Norway
| | - Hannah Davis
- Division of Medical Genetics, Department of Human Genetics, Emory University School of Medicine; Atlanta, GA, USA
| | - Charlotte Peinhardt
- Division of Medical Genetics, Department of Human Genetics, Emory University School of Medicine; Atlanta, GA, USA
| | - Mahmoud Koko
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen; Tübingen, Germany
| | - Rohini K Coorg
- Department of Pediatrics and Neurology, Neurophysiology and Epilepsy, Baylor College of Medicine; Houston, Texas, USA
| | - Steffen Syrbe
- Division of Paediatric Epileptology, Centre for Paediatric and Adolescent Medicine, University Hospital Heidelberg; Heidelberg, Germany
| | - Astrid Bertsche
- University Hospital for Children and Adolescents, Neuropaediatrics; Rostock, Germany.,University Hospital for Children and Adolescents, Center for Pediatric Research; Leipzig, Germany
| | | | - Tue Diemer
- Department of Clinical Genetics, Aalborg University Hospital; Aalborg, Denmark
| | - Christina D Fenger
- Department of Epilepsy Genetics and Personalized Treatment, The Danish Epilepsy Centre; Dianalund, Denmark.,Department of Regional Health Research, University of Southern Denmark; Odense, Denmark
| | - Konrad Platzer
- Institute of Human Genetics, University of Leipzig Medical Center; Leipzig, Germany
| | - Evan E Eichler
- Department of Genome Sciences, University of Washington School of Medicine; Seattle, WA, USA.,Howard Hughes Medical Institute, University of Washington; Seattle, WA 98195, USA
| | - Holger Lerche
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen; Tübingen, Germany
| | - Johannes R Lemke
- Institute of Human Genetics, University of Leipzig Medical Center; Leipzig, Germany
| | - Mary Chebib
- Brain and Mind Centre, School of Pharmacy, Faculty of Medicine and Health, The University of Sydney; Sydney, New South Wales, Australia
| | - Rikke S Møller
- Department of Epilepsy Genetics and Personalized Treatment, The Danish Epilepsy Centre; Dianalund, Denmark.,Department of Regional Health Research, University of Southern Denmark; Odense, Denmark
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10
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Walczak-Nowicka ŁJ, Herbet M. Acetylcholinesterase Inhibitors in the Treatment of Neurodegenerative Diseases and the Role of Acetylcholinesterase in their Pathogenesis. Int J Mol Sci 2021; 22:9290. [PMID: 34502198 PMCID: PMC8430571 DOI: 10.3390/ijms22179290] [Citation(s) in RCA: 48] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2021] [Revised: 08/24/2021] [Accepted: 08/25/2021] [Indexed: 12/21/2022] Open
Abstract
Acetylcholinesterase (AChE) plays an important role in the pathogenesis of neurodegenerative diseases by influencing the inflammatory response, apoptosis, oxidative stress and aggregation of pathological proteins. There is a search for new compounds that can prevent the occurrence of neurodegenerative diseases and slow down their course. The aim of this review is to present the role of AChE in the pathomechanism of neurodegenerative diseases. In addition, this review aims to reveal the benefits of using AChE inhibitors to treat these diseases. The selected new AChE inhibitors were also assessed in terms of their potential use in the described disease entities. Designing and searching for new drugs targeting AChE may in the future allow the discovery of therapies that will be effective in the treatment of neurodegenerative diseases.
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Affiliation(s)
| | - Mariola Herbet
- Chair and Department of Toxicology, Faculty of Pharmacy, Medical University of Lublin, Jaczewskiego 8bStreet, 20-090 Lublin, Poland;
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11
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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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12
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Schöbi D, Homberg F, Frässle S, Endepols H, Moran RJ, Friston KJ, Tittgemeyer M, Heinzle J, Stephan KE. Model-based prediction of muscarinic receptor function from auditory mismatch negativity responses. Neuroimage 2021; 237:118096. [PMID: 33940149 DOI: 10.1016/j.neuroimage.2021.118096] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 04/12/2021] [Accepted: 04/19/2021] [Indexed: 01/09/2023] Open
Abstract
Drugs affecting neuromodulation, for example by dopamine or acetylcholine, take centre stage among therapeutic strategies in psychiatry. These neuromodulators can change both neuronal gain and synaptic plasticity and therefore affect electrophysiological measures. An important goal for clinical diagnostics is to exploit this effect in the reverse direction, i.e., to infer the status of specific neuromodulatory systems from electrophysiological measures. In this study, we provide proof-of-concept that the functional status of cholinergic (specifically muscarinic) receptors can be inferred from electrophysiological data using generative (dynamic causal) models. To this end, we used epidural EEG recordings over two auditory cortical regions during a mismatch negativity (MMN) paradigm in rats. All animals were treated, across sessions, with muscarinic receptor agonists and antagonists at different doses. Together with a placebo condition, this resulted in five levels of muscarinic receptor status. Using a dynamic causal model - embodying a small network of coupled cortical microcircuits - we estimated synaptic parameters and their change across pharmacological conditions. The ensuing parameter estimates associated with (the neuromodulation of) synaptic efficacy showed both graded muscarinic effects and predictive validity between agonistic and antagonistic pharmacological conditions. This finding illustrates the potential utility of generative models of electrophysiological data as computational assays of muscarinic function. In application to EEG data of patients from heterogeneous spectrum diseases, e.g. schizophrenia, such models might help identify subgroups of patients that respond differentially to cholinergic treatments. SIGNIFICANCE STATEMENT: In psychiatry, the vast majority of pharmacological treatments affect actions of neuromodulatory transmitters, e.g. dopamine or acetylcholine. As treatment is largely trial-and-error based, one of the goals for computational psychiatry is to construct mathematical models that can serve as "computational assays" and infer the status of specific neuromodulatory systems in individual patients. This translational neuromodeling strategy has great promise for electrophysiological data in particular but requires careful validation. The present study demonstrates that the functional status of cholinergic (muscarinic) receptors can be inferred from electrophysiological data using dynamic causal models of neural circuits. While accuracy needs to be enhanced and our results must be replicated in larger samples, our current results provide proof-of-concept for computational assays of muscarinic function using EEG.
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Affiliation(s)
- Dario Schöbi
- Translational Neuromodeling Unit, Institute for Biomedical Engineering, University of Zurich & Swiss Institute of Technology (ETH Zurich), Wilfriedstrasse 6, 8032, Zurich, Switzerland
| | - Fabienne Homberg
- Boston Scientific Medizintechnik GmbH, Daniel-Goldbach-Strasse 17-27, 40880 Ratingen, Germany
| | - Stefan Frässle
- Translational Neuromodeling Unit, Institute for Biomedical Engineering, University of Zurich & Swiss Institute of Technology (ETH Zurich), Wilfriedstrasse 6, 8032, Zurich, Switzerland
| | - Heike Endepols
- Preclinical Imaging Group, Department of Nuclear Medicine, Faculty of Medicine and University Hospital Cologne, University of Cologne, 50923 Cologne, Germany
| | - Rosalyn J Moran
- Department of Neuroimaging, Institute for Psychiatry, Psychology & Neuroscience, King's College London, De Crespigny Park, London Se5 8AF, UK
| | - Karl J Friston
- Wellcome Centre for Human Neuroimaging, University College London, 12 Queen Square, London, WC1N, 3AR, UK
| | - Marc Tittgemeyer
- Max Planck Institute for Metabolism Research, Gleueler Strasse 50, 50931 Cologne, Germany; Cluster of Excellence in Cellular Stress and Aging associated Disease (CECAD), 50931 Cologne, Germany
| | - Jakob Heinzle
- Translational Neuromodeling Unit, Institute for Biomedical Engineering, University of Zurich & Swiss Institute of Technology (ETH Zurich), Wilfriedstrasse 6, 8032, Zurich, Switzerland.
| | - Klaas Enno Stephan
- Translational Neuromodeling Unit, Institute for Biomedical Engineering, University of Zurich & Swiss Institute of Technology (ETH Zurich), Wilfriedstrasse 6, 8032, Zurich, Switzerland; Wellcome Centre for Human Neuroimaging, University College London, 12 Queen Square, London, WC1N, 3AR, UK; Max Planck Institute for Metabolism Research, Gleueler Strasse 50, 50931 Cologne, Germany
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13
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Benfante R, Di Lascio S, Cardani S, Fornasari D. Acetylcholinesterase inhibitors targeting the cholinergic anti-inflammatory pathway: a new therapeutic perspective in aging-related disorders. Aging Clin Exp Res 2021; 33:823-834. [PMID: 31583530 DOI: 10.1007/s40520-019-01359-4] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Accepted: 09/18/2019] [Indexed: 11/26/2022]
Abstract
Neuroinflammation and cholinergic dysfunction, leading to cognitive impairment, are hallmarks of aging and neurodegenerative disorders, including Alzheimer's disease (AD). Acetylcholinesterase inhibitors (AChEI), the symptomatic therapy in AD, attenuate and delay the cognitive deficit by enhancing cholinergic synapses. The α7 nicotinic acetylcholine (ACh) receptor has shown a double-edged sword feature, as it binds with high affinity Aβ1-42, promoting intracellular accumulation and Aβ-induced tau phosphorylation, but also exerts neuroprotection by stimulating anti-apoptotic pathways. Moreover, it mediates peripheral and central anti-inflammatory response, being the effector player of the activation of the cholinergic anti-inflammatory pathway (CAIP), that, by decreasing the release of TNF-α, IL-1β, and IL-6, it may have a role in improving cognition. The finding in preclinical models that, in addition to their major function (choline esterase inhibition) AChEIs have neuroprotective properties mediated via α7nAChR and modulate innate immunity, possibly as a result of the increased availability of acetylcholine activating the CAIP, pave the way for new pharmacological intervention in AD and other neurological disorders that are characterized by neuroinflammation. CHRFAM7A is a human-specific gene acting as a dominant negative inhibitor of α7nAChR function, also suggesting a role in affecting human cognition and memory by altering α7nAChR activities in the central nervous system (CNS). This review will summarize the current knowledge on the cholinergic anti-inflammatory pathway in aging-related disorders, and will argue that the presence of the human-restricted CHRFAM7A gene might play a fundamental role in the regulation of CAIP and in the response to AChEI.
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Affiliation(s)
- Roberta Benfante
- CNR-Neuroscience Institute, Via Vanvitelli 32, 20129, Milan, Italy.
- Dept. Medical Biotechnology and Translational Medicine, Università degli Studi di Milano, Via Vanvitelli 32, 20129, Milan, Italy.
| | - Simona Di Lascio
- Dept. Medical Biotechnology and Translational Medicine, Università degli Studi di Milano, Via Vanvitelli 32, 20129, Milan, Italy
| | - Silvia Cardani
- Dept. Medical Biotechnology and Translational Medicine, Università degli Studi di Milano, Via Vanvitelli 32, 20129, Milan, Italy
| | - Diego Fornasari
- CNR-Neuroscience Institute, Via Vanvitelli 32, 20129, Milan, Italy
- Dept. Medical Biotechnology and Translational Medicine, Università degli Studi di Milano, Via Vanvitelli 32, 20129, Milan, Italy
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14
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Liao VWY, Chebib M, Ahring PK. Efficient expression of concatenated α1β2δ and α1β3δ GABA A receptors, their pharmacology and stoichiometry. Br J Pharmacol 2021; 178:1556-1573. [PMID: 33491192 DOI: 10.1111/bph.15380] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 12/28/2020] [Accepted: 01/11/2021] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND AND PURPOSE GABAA receptors containing δ-subunits are notorious for being difficult to study in vitro due to heterogeneity of expressed receptor populations and low GABA-evoked current amplitudes. Thus, there are some published misconceptions and contradictory conclusions made regarding the pharmacology and stoichiometry of δ-containing receptors. The aim of this study was to obtain robust homogenous expression of α1βδ receptors for in-depth investigation. EXPERIMENTAL APPROACH Novel δ-containing pentameric concatenated constructs were designed. The resulting α1β2δ and α1β3δ GABAA receptor concatemers were investigated by two-electrode voltage-clamp electrophysiology using Xenopus laevis oocytes. KEY RESULTS First, while homogenous α1βδ GABAA receptor pools could not be obtained by manipulating the ratio of injected cRNAs of free α1, β2/3, and δ subunits, concatenated pentameric α1β2δ and α1β3δ constructs resulted in robust expression levels of concatemers. Second, by using optimised constructs that give unidirectional assembly of concatemers, we found that the δ subunit cannot directly participate in GABA binding and receptor activation. Hence, functional δ-containing receptors are likely to all have a conventional 2α:2β:1δ stoichiometry arranged as βαβαδ when viewed counterclockwise from the extracellular side. Third, α1β2/3δ receptors were found to express efficiently in X. laevis oocytes but have a low estimated open probability of ~0.5% upon GABA activation. Because of this, these receptors are uniquely susceptible to positive allosteric modulation by, for example, neurosteroids. CONCLUSION AND IMPLICATIONS Our data answer important outstanding questions regarding the pharmacology and stoichiometry of α1δ-containing GABAA receptors and pave the way for future analysis and drug discovery efforts.
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Affiliation(s)
- Vivian Wan Yu Liao
- Brain and Mind Centre, Sydney Pharmacy School, Faculty of Medicine and Health, The University of Sydney, Sydney, New South Wales, Australia
| | - Mary Chebib
- Brain and Mind Centre, Sydney Pharmacy School, Faculty of Medicine and Health, The University of Sydney, Sydney, New South Wales, Australia
| | - Philip Kiaer Ahring
- Brain and Mind Centre, Sydney Pharmacy School, Faculty of Medicine and Health, The University of Sydney, Sydney, New South Wales, Australia
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15
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Metz CN, Pavlov VA. Treating disorders across the lifespan by modulating cholinergic signaling with galantamine. J Neurochem 2021; 158:1359-1380. [PMID: 33219523 PMCID: PMC10049459 DOI: 10.1111/jnc.15243] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 11/15/2020] [Accepted: 11/16/2020] [Indexed: 02/06/2023]
Abstract
Advances in understanding the regulatory functions of the nervous system have revealed neural cholinergic signaling as a key regulator of cytokine responses and inflammation. Cholinergic drugs, including the centrally acting acetylcholinesterase inhibitor, galantamine, which are in clinical use for the treatment of Alzheimer's disease and other neurodegenerative and neuropsychiatric disorders, have been rediscovered as anti-inflammatory agents. Here, we provide a timely update on this active research and clinical developments. We summarize the involvement of cholinergic mechanisms and inflammation in the pathobiology of Alzheimer's disease, Parkinson's disease, and schizophrenia, and the effectiveness of galantamine treatment. We also highlight recent findings demonstrating the effects of galantamine in preclinical and clinical settings of numerous conditions and diseases across the lifespan that are characterized by immunological, neurological, and metabolic dysfunction.
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Affiliation(s)
- Christine N Metz
- The Feinstein Institutes for Medical Research, Northwell Health, Manhasset, NY, USA.,Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, Hempstead, NY, USA
| | - Valentin A Pavlov
- The Feinstein Institutes for Medical Research, Northwell Health, Manhasset, NY, USA.,Donald and Barbara Zucker School of Medicine at Hofstra/Northwell, Hempstead, NY, USA
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16
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Koola MM, Looney SW, Hong H, Pillai A, Hou W. Meta-analysis of randomized controlled trials of galantamine in schizophrenia: significant cognitive enhancement. Psychiatry Res 2020; 291:113285. [PMID: 32763546 DOI: 10.1016/j.psychres.2020.113285] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 07/08/2020] [Accepted: 07/09/2020] [Indexed: 12/11/2022]
Abstract
Cognitive impairments are core features of schizophrenia and the best predictor of functional outcome. Cholinergic system and alpha-7 nicotinic acetylcholine (α7nACh) receptors are strongly implicated in the pathophysiologic mechanisms associated with cognitive impairments in schizophrenia. Galantamine is not only a reversible, competitive inhibitor of acetylcholinesterase but also a type I positive allosteric modulator of α7nACh receptors. The objective of this meta-analysis was to examine the efficacy of galantamine for cognitive symptoms of schizophrenia. In the meta-analysis that included six randomized controlled trials (RCTs, N=226), cognitive impairments significantly improved with galantamine compared to placebo, with a small Hedges' g effect size of 0.233. This finding is consistent with other RCTs in schizophrenia with medications with a similar mechanism of action. On the basis of the results from all the failed (although some efficacy has been shown) RCTs to date in schizophrenia, targeting only one pathophysiologic mechanism may be insufficient to detect a clinically meaningful signal. Nicotinergic medications, like any other add-on medications, are unlikely to be effective as stand-alone medications. Hence, these medications may have to be combined with other medications with complementary mechanisms such as glutamatergic/N-methyl-D-aspartate systems to detect a meaningful effect size for the three domains of psychopathology.
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Affiliation(s)
- Maju Mathew Koola
- Department of Psychiatry and Behavioral Health, Stony Brook University Renaissance School of Medicine, Stony Brook, NY, 11794, USA.
| | - Stephen W Looney
- Department of Population Health Sciences, Division of Biostatistics and Data Science, Augusta University, Augusta, GA, USA
| | - Houlin Hong
- Department of Family, Population and Preventive Medicine, School of Medicine, Stony Brook University, Stony Brook, NY, USA
| | - Anilkumar Pillai
- Department of Psychiatry and Health Behavior, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Wei Hou
- Department of Family, Population and Preventive Medicine, School of Medicine, Stony Brook University, Stony Brook, NY, USA
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17
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Moerke MJ, McMahon LR, Wilkerson JL. More than Smoke and Patches: The Quest for Pharmacotherapies to Treat Tobacco Use Disorder. Pharmacol Rev 2020; 72:527-557. [PMID: 32205338 DOI: 10.1124/pr.119.018028] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Tobacco use is a persistent public health issue. It kills up to half its users and is the cause of nearly 90% of all lung cancers. The main psychoactive component of tobacco is nicotine, primarily responsible for its abuse-related effects. Accordingly, most pharmacotherapies for smoking cessation target nicotinic acetylcholine receptors (nAChRs), nicotine's major site of action in the brain. The goal of the current review is twofold: first, to provide a brief overview of the most commonly used behavioral procedures for evaluating smoking cessation pharmacotherapies and an introduction to pharmacokinetic and pharmacodynamic properties of nicotine important for consideration in the development of new pharmacotherapies; and second, to discuss current and potential future pharmacological interventions aimed at decreasing tobacco use. Attention will focus on the potential for allosteric modulators of nAChRs to offer an improvement over currently approved pharmacotherapies. Additionally, given increasing public concern for the potential health consequences of using electronic nicotine delivery systems, which allow users to inhale aerosolized solutions as an alternative to smoking tobacco, an effort will be made throughout this review to address the implications of this relatively new form of nicotine delivery, specifically as it relates to smoking cessation. SIGNIFICANCE STATEMENT: Despite decades of research that have vastly improved our understanding of nicotine and its effects on the body, only a handful of pharmacotherapies have been successfully developed for use in smoking cessation. Thus, investigation of alternative pharmacological strategies for treating tobacco use disorder remains active; allosteric modulators of nicotinic acetylcholine receptors represent one class of compounds currently under development for this purpose.
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Affiliation(s)
- M J Moerke
- Division of Preclinical Pharmacology, National Institute on Drug Abuse, National Institutes of Health, Baltimore, Maryland (M.J.M.) and Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, Florida (L.R.M., J.L.W.)
| | - L R McMahon
- Division of Preclinical Pharmacology, National Institute on Drug Abuse, National Institutes of Health, Baltimore, Maryland (M.J.M.) and Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, Florida (L.R.M., J.L.W.)
| | - J L Wilkerson
- Division of Preclinical Pharmacology, National Institute on Drug Abuse, National Institutes of Health, Baltimore, Maryland (M.J.M.) and Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, Florida (L.R.M., J.L.W.)
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18
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Liao VWY, Kusay AS, Balle T, Ahring PK. Heterologous expression of concatenated nicotinic ACh receptors: Pros and cons of subunit concatenation and recommendations for construct designs. Br J Pharmacol 2020; 177:4275-4295. [PMID: 32627170 DOI: 10.1111/bph.15188] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Revised: 06/15/2020] [Accepted: 06/26/2020] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND AND PURPOSE Concatenation of Cys-loop receptor subunits is a commonly used technique to ensure experimental control of receptor assembly. However, we recently demonstrated that widely used constructs did not lead to the expression of uniform pools of ternary and more complex receptors. The aim was therefore to identify viable strategies for designing concatenated constructs that would allow strict control of resultant receptor pools. EXPERIMENTAL APPROACH Concatenated dimeric, tetrameric, and pentameric α4β2-containing nicotinic ACh (nACh) receptor constructs were designed with successively shorter linker lengths and expressed in Xenopus laevis oocytes. Resulting receptor stoichiometries were investigated by functional analysis in two-electrode voltage-clamp experiments. Molecular dynamics simulations were performed to investigate potential effects of linkers on the 3D structure of concatemers. KEY RESULTS Dimeric constructs were found to be unreliable and should be avoided for expression of ternary receptors. By introducing two short linkers, we obtained efficient expression of uniform receptor pools with tetrameric and pentameric constructs. However, linkers should not be excessively short as that introduces strain on the 3D structure of concatemers. CONCLUSION AND IMPLICATIONS The data demonstrate that design of concatenated Cys-loop receptors requires a compromise between the desire for control of assembly and avoiding introduction of strain on the resulting protein. The overall best strategy was found to be pentameric constructs with carefully optimised linker lengths. Our findings will advance studies of ternary or more complex Cys-loop receptors as well as enabling detailed analysis of how pharmacological agents interact with stoichiometry-specific binding sites.
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Affiliation(s)
- Vivian Wan Yu Liao
- Brain and Mind Centre, The University of Sydney, 94 Mallett Street, Camperdown, NSW, 2050, Australia.,Sydney Pharmacy School, Faculty of Medicine and Health, The University of Sydney, NSW, 2006, Australia
| | - Ali Saad Kusay
- Brain and Mind Centre, The University of Sydney, 94 Mallett Street, Camperdown, NSW, 2050, Australia.,Sydney Pharmacy School, Faculty of Medicine and Health, The University of Sydney, NSW, 2006, Australia
| | - Thomas Balle
- Brain and Mind Centre, The University of Sydney, 94 Mallett Street, Camperdown, NSW, 2050, Australia.,Sydney Pharmacy School, Faculty of Medicine and Health, The University of Sydney, NSW, 2006, Australia
| | - Philip Kiaer Ahring
- Brain and Mind Centre, The University of Sydney, 94 Mallett Street, Camperdown, NSW, 2050, Australia.,Sydney Pharmacy School, Faculty of Medicine and Health, The University of Sydney, NSW, 2006, Australia
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Allosterism of Nicotinic Acetylcholine Receptors: Therapeutic Potential for Neuroinflammation Underlying Brain Trauma and Degenerative Disorders. Int J Mol Sci 2020; 21:ijms21144918. [PMID: 32664647 PMCID: PMC7404387 DOI: 10.3390/ijms21144918] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 07/06/2020] [Accepted: 07/10/2020] [Indexed: 12/21/2022] Open
Abstract
Inflammation is a key physiological phenomenon that can be pervasive when dysregulated. Persistent chronic inflammation precedes several pathophysiological conditions forming one of the critical cellular homeostatic checkpoints. With a steady global surge in inflammatory diseases, it is imperative to delineate underlying mechanisms and design suitable drug molecules targeting the cellular partners that mediate and regulate inflammation. Nicotinic acetylcholine receptors have a confirmed role in influencing inflammatory pathways and have been a subject of scientific scrutiny underlying drug development in recent years. Drugs designed to target allosteric sites on the nicotinic acetylcholine receptors present a unique opportunity to unravel the role of the cholinergic system in regulating and restoring inflammatory homeostasis. Such a therapeutic approach holds promise in treating several inflammatory conditions and diseases with inflammation as an underlying pathology. Here, we briefly describe the potential of cholinergic allosterism and some allosteric modulators as a promising therapeutic option for the treatment of neuroinflammation.
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20
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Structure-Based Discovery of Dual-Target Hits for Acetylcholinesterase and the α7 Nicotinic Acetylcholine Receptors: In Silico Studies and In Vitro Confirmation. Molecules 2020; 25:molecules25122872. [PMID: 32580406 PMCID: PMC7355937 DOI: 10.3390/molecules25122872] [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: 06/03/2020] [Revised: 06/15/2020] [Accepted: 06/15/2020] [Indexed: 11/17/2022] Open
Abstract
Despite extensive efforts in the development of drugs for complex neurodegenerative diseases, treatment often remains challenging or ineffective, and hence new treatment strategies are necessary. One approach is the design of multi-target drugs, which can potentially address the complex nature of disorders such as Alzheimer's disease. We report a method for high throughput virtual screening aimed at identifying new dual target hit molecules. One of the identified hits, N,N-dimethyl-1-(4-(3-methyl-[1,2,4]triazolo[4,3-a]pyrimidin-6-yl)phenyl)ethan-1-amine (Ý;mir-2), has dual-activity as an acetylcholinesterase (AChE) inhibitor and as an α7 nicotinic acetylcholine receptor (α7 nAChR) agonist. Using computational chemistry methods, parallel and independent screening of a virtual compound library consisting of 3,848,234 drug-like and commercially available molecules from the ZINC15 database, resulted in an intersecting set of 57 compounds, that potentially possess activity at both of the two protein targets. Based on ligand efficiency as well as scaffold and molecular diversity, 16 of these compounds were purchased for in vitro validation by Ellman's method and two-electrode voltage-clamp electrophysiology. Ý;mir-2 was shown to exhibit the desired activity profile (AChE IC50 = 2.58 ± 0.96 µM; α7 nAChR activation = 7.0 ± 0.9% at 200 µM) making it the first reported compound with this particular profile and providing further evidence of the feasibility of in silico methods for the identification of novel multi-target hit molecules.
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21
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Millan MJ, Dekeyne A, Gobert A, Brocco M, Mannoury la Cour C, Ortuno JC, Watson D, Fone KCF. Dual-acting agents for improving cognition and real-world function in Alzheimer's disease: Focus on 5-HT6 and D3 receptors as hubs. Neuropharmacology 2020; 177:108099. [PMID: 32525060 DOI: 10.1016/j.neuropharm.2020.108099] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 04/02/2020] [Accepted: 04/03/2020] [Indexed: 01/01/2023]
Abstract
To date, there are no interventions that impede the inexorable progression of Alzheimer's disease (AD), and currently-available drugs cholinesterase (AChE) inhibitors and the N-Methyl-d-Aspartate receptor antagonist, memantine, offer only modest symptomatic benefit. Moreover, a range of mechanistically-diverse agents (glutamatergic, histaminergic, monoaminergic, cholinergic) have disappointed in clinical trials, alone and/or in association with AChE inhibitors. This includes serotonin (5-HT) receptor-6 antagonists, despite compelling preclinical observations in rodents and primates suggesting a positive influence on cognition. The emphasis has so far been on high selectivity. However, for a multi-factorial disorder like idiopathic AD, 5-HT6 antagonists possessing additional pharmacological actions might be more effective, by analogy to "multi-target" antipsychotics. Based on this notion, drug discovery programmes have coupled 5-HT6 blockade to 5-HT4 agonism and inhibition of AchE. Further, combined 5-HT6/dopamine D3 receptor (D3) antagonists are of especial interest since D3 blockade mirrors 5-HT6 antagonism in exerting broad-based pro-cognitive properties in animals. Moreover, 5-HT6 and dopamine D3 antagonists promote neurocognition and social cognition via both distinctive and convergent actions expressed mainly in frontal cortex, including suppression of mTOR over-activation and reinforcement of cholinergic and glutamatergic transmission. In addition, 5-HT6 blockade affords potential anti-anxiety, anti-depressive and anti-epileptic properties, and antagonising 5-HT6 receptors may be associated with neuroprotective ("disease-modifying") properties. Finally D3 antagonism may counter psychotic episodes and D3 receptors themselves offer a promising hub for multi-target agents. The present article reviews the status of "R and D" into multi-target 5-HT6 and D3 ligands for improved treatment of AD and other neurodegenerative disorders of aging. This article is part of the special issue entitled 'Serotonin Research: Crossing Scales and Boundaries'.
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Affiliation(s)
- Mark J Millan
- Centre for Therapeutic Innovation in Neuropsychiatry, Institut de Recherche Servier, 78290, Croissy sur Seine, France.
| | - Anne Dekeyne
- Centre for Therapeutic Innovation in Neuropsychiatry, Institut de Recherche Servier, 78290, Croissy sur Seine, France
| | - Alain Gobert
- Centre for Therapeutic Innovation in Neuropsychiatry, Institut de Recherche Servier, 78290, Croissy sur Seine, France
| | - Mauricette Brocco
- Centre for Therapeutic Innovation in Neuropsychiatry, Institut de Recherche Servier, 78290, Croissy sur Seine, France
| | - Clotilde Mannoury la Cour
- Centre for Therapeutic Innovation in Neuropsychiatry, Institut de Recherche Servier, 78290, Croissy sur Seine, France
| | - Jean-Claude Ortuno
- Centre for Excellence in Chemistry, Institut de Recherche Servier, 78290, Croissy sur Seine, France
| | - David Watson
- School of Life Sciences, Queen's Medical Centre, The University of Nottingham, NG7 2UH, England, UK
| | - Kevin C F Fone
- School of Life Sciences, Queen's Medical Centre, The University of Nottingham, NG7 2UH, England, UK
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22
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Potasiewicz A, Krawczyk M, Gzielo K, Popik P, Nikiforuk A. Positive allosteric modulators of alpha 7 nicotinic acetylcholine receptors enhance procognitive effects of conventional anti-Alzheimer drugs in scopolamine-treated rats. Behav Brain Res 2020; 385:112547. [DOI: 10.1016/j.bbr.2020.112547] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 02/06/2020] [Accepted: 02/07/2020] [Indexed: 01/13/2023]
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Lewis AS, Picciotto MR. Regulation of aggressive behaviors by nicotinic acetylcholine receptors: Animal models, human genetics, and clinical studies. Neuropharmacology 2020; 167:107929. [PMID: 32058178 PMCID: PMC7080580 DOI: 10.1016/j.neuropharm.2019.107929] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 12/18/2019] [Accepted: 12/25/2019] [Indexed: 12/12/2022]
Abstract
Neuropsychiatric disorders are frequently complicated by aggressive behaviors. For some individuals, existing behavioral and psychopharmacological treatments are ineffective or confer significant side effects, necessitating development of new ways to treat patients with severe aggression. Nicotinic acetylcholine receptors (nAChRs) are a large and diverse family of ligand-gated ion channels expressed throughout the brain that influence behaviors highly relevant for neuropsychiatric disorders, including attention, mood, and impulsivity. Nicotine and other drugs targeting nAChRs can reduce aggression in animal models of offensive, defensive, and predatory aggression, as well as in human laboratory studies. Human genetic studies have suggested a relationship between the CHRNA7 gene encoding the alpha-7 nAChR and aggressive behavior, although these effects are heterogeneous and strongly influenced by genetic background and environment. Here we review animal, human genetic, and clinical studies supporting a consistent role of nicotine and nAChR signaling in modulation of aggressive behaviors. We integrate findings from recent studies of aggression neuroscience, discuss the circuitry that may be involved in these effects of nAChRs, and identify multiple key questions that must be answered prior to safe and effective translation for human patients. This article is part of the special issue on 'Contemporary Advances in Nicotine Neuropharmacology'.
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Affiliation(s)
- Alan S Lewis
- Department of Psychiatry and Behavioral Sciences, Vanderbilt University Medical Center, Nashville, TN, USA; Department of Neurology, Vanderbilt University Medical Center, Nashville, TN, USA; Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, TN, USA; Center for Cognitive Medicine, Vanderbilt University Medical Center, Nashville, TN, USA; Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN, USA.
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Stone TW. Does kynurenic acid act on nicotinic receptors? An assessment of the evidence. J Neurochem 2020; 152:627-649. [PMID: 31693759 PMCID: PMC7078985 DOI: 10.1111/jnc.14907] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Revised: 10/19/2019] [Accepted: 10/30/2019] [Indexed: 02/06/2023]
Abstract
As a major metabolite of kynurenine in the oxidative metabolism of tryptophan, kynurenic acid is of considerable biological and clinical importance as an endogenous antagonist of glutamate in the central nervous system. It is most active as an antagonist at receptors sensitive to N-methyl-D-aspartate (NMDA) which regulate neuronal excitability and plasticity, brain development and behaviour. It is also thought to play a causative role in hypo-glutamatergic conditions such as schizophrenia, and a protective role in several neurodegenerative disorders, notably Huntington's disease. An additional hypothesis, that kynurenic acid could block nicotinic receptors for acetylcholine in the central nervous system has been proposed as an alternative mechanism of action of kynurenate. However, the evidence for this alternative mechanism is highly controversial, partly because at least eight earlier studies concluded that kynurenic acid blocked NMDA receptors but not nicotinic receptors and five subsequent, independent studies designed to repeat the results have failed to do so. Many studies considered to support the alternative 'nicotinic' hypothesis have been based on the use of analogs of kynurenate such as 7-chloro-kynurenic acid, or putatively nicotinic modulators such as galantamine, but a detailed analysis of the pharmacology of these compounds suggests that the results have often been misinterpreted, especially since the pharmacology of galantamine itself has been disputed. This review examines the evidence in detail, with the conclusion that there is no confirmed, reliable evidence for an antagonist activity of kynurenic acid at nicotinic receptors. Therefore, since there is overwhelming evidence for kynurenate acting at ionotropic glutamate receptors, especially NMDAR glutamate and glycine sites, with some activity at GPR35 sites and Aryl Hydrocarbon Receptors, results with kynurenic acid should be interpreted only in terms of these confirmed sites of action.
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Affiliation(s)
- Trevor W. Stone
- Institute for Neuroscience and PsychologyUniversity of GlasgowGlasgowG12 8QQUK
- Present address:
Kennedy InstituteNDORMSUniversity of OxfordOxfordOX3 7FYUK
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Wilkerson JL, Deba F, Crowley ML, Hamouda AK, McMahon LR. Advances in the In vitro and In vivo pharmacology of Alpha4beta2 nicotinic receptor positive allosteric modulators. Neuropharmacology 2020; 168:108008. [PMID: 32113032 DOI: 10.1016/j.neuropharm.2020.108008] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Revised: 02/08/2020] [Accepted: 02/11/2020] [Indexed: 11/29/2022]
Abstract
Receptors containing α4 and β2 subunits are a major neuronal nicotinic acetylcholine receptor (nAChR) subtype in the brain. This receptor plays a critical role in nicotine addiction, with potential smoking cessation therapeutics producing modulation of α4β2 nAChR. In addition, compounds that act as agonists at α4β2 nAChR may be useful for the treatment of pathological pain. Further, as the α4β2 nAChR has been implicated in cognition, therapeutics that act as α4β2 nAChR agonists are also being examined as treatments for cognitive disorders and neurological diseases that impact cognitive function, such as Alzheimer's disease and schizophrenia. This review will cover the molecular in vitro evidence that allosteric modulators of the α4β2 neuronal nAChR provide several advantages over traditional α4β2 nAChR orthosteric ligands. Specifically, we explore the concept that nAChR allosteric modulators allow for greater pharmacological selectivity, while minimizing potential deleterious off-target effects. Further, here we discuss the development and preclinical in vivo behavioral assessment of allosteric modulators at the α4β2 neuronal nAChR as therapeutics for smoking cessation, pathological pain, as well as cognitive disorders and neurological diseases that impact cognitive function. This article is part of the special issue on 'Contemporary Advances in Nicotine Neuropharmacology'.
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Affiliation(s)
- Jenny L Wilkerson
- Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, FL, 32610, United States.
| | - Farah Deba
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Texas at Tyler, Tyler, TX, 75799, United States
| | - Morgan L Crowley
- Department of Medicinal Chemistry, College of Pharmacy, University of Florida, Gainesville, FL, 32610, United States
| | - Ayman K Hamouda
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Texas at Tyler, Tyler, TX, 75799, United States.
| | - Lance R McMahon
- Department of Pharmacodynamics, College of Pharmacy, University of Florida, Gainesville, FL, 32610, United States.
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26
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Jackson A, Alkhlaif Y, Papke RL, Brunzell DH, Damaj MI. Impact of modulation of the α7 nicotinic acetylcholine receptor on nicotine reward in the mouse conditioned place preference test. Psychopharmacology (Berl) 2019; 236:3593-3599. [PMID: 31302720 PMCID: PMC6895411 DOI: 10.1007/s00213-019-05331-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Accepted: 07/08/2019] [Indexed: 12/26/2022]
Abstract
RATIONALE The α7 nicotinic acetylcholine receptor (nAChR) has been implicated as a target in modulating nicotine reward. However, the effect of pharmacological agents that have been shown to alter the channel properties of the α7 nAChR is not well understood in nicotine reward. OBJECTIVES This study aimed to investigate the impact of α7 nAChR pharmacological modulation on nicotine conditioned place preference (CPP) in mice by using positive allosteric modulators (PAMs) and a silent agonist. METHODS The effect of the orthosteric α7 nAChR full agonist PNU282987 (1.3 and 9 mg/kg, s.c.), Type I α7 PAM NS1738 (1 and 10 mg/kg; i.p.), the Type II α7 PAM PNU120596 (0.3, 1, and 3 mg/kg, i.p.), and the α7 silent agonist NS6740 (1 and 3 mg/kg, i.p) on nicotine CPP was measured in mice. Mice were conditioned with either saline or nicotine (0.5 mg/kg) for 3 days in the CPP paradigm. RESULTS The α7 full orthosteric agonist PNU282987 and the Type II α7 nAChR PAM PNU120596 reduced nicotine CPP, while the silent agonist NS6740 and Type I PAM NS1738 had no effect. The effects of PNU282987 and PNU120596 did not have an effect on morphine CPP. CONCLUSIONS Taken together, our results suggest that modulation of the α7 nAChR can play important roles in nicotine CPP in mice. In addition, the Type II α7 nAChR PAM PNU120596 attenuated nicotine reward suggesting that endogenous acetylcholine/choline tone is sufficient to reduce nicotine CPP. These findings highlight a beneficial effect of using α7 nAChR PAMs in nicotine reward.
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Affiliation(s)
- Asti Jackson
- Department of Psychiatry, Yale School of Medicine, 34 Park St., New Haven, CT, 06519, USA.
| | - Y. Alkhlaif
- Department of Pharmacology and Toxicology, School of Medicine, Virginia Commonwealth University, Richmond, VA 23298-0613, USA
| | - R. L. Papke
- Department of Pharmacology and Therapeutics, University of Florida, PO Box 100267, Gainesville, FL 32610-0267, USA
| | - D. H. Brunzell
- Department of Pharmacology and Toxicology, School of Medicine, Virginia Commonwealth University, Richmond, VA 23298-0613, USA
| | - M. I. Damaj
- Department of Pharmacology and Toxicology, School of Medicine, Virginia Commonwealth University, Richmond, VA 23298-0613, USA
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Trujillo-Chacón LM, Alarcón-Enos JE, Céspedes-Acuña CL, Bustamante L, Baeza M, López MG, Fernández-Mendívil C, Cabezas F, Pastene-Navarrete ER. Neuroprotective activity of isoquinoline alkaloids from of Chilean Amaryllidaceae plants against oxidative stress-induced cytotoxicity on human neuroblastoma SH-SY5Y cells and mouse hippocampal slice culture. Food Chem Toxicol 2019; 132:110665. [DOI: 10.1016/j.fct.2019.110665] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2019] [Revised: 07/02/2019] [Accepted: 07/04/2019] [Indexed: 12/13/2022]
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28
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Silva GM, Barcelos MP, Poiani JGC, Hage-Melim LIDS, da Silva CHTDP. Allosteric Modulators of Potential Targets Related to Alzheimer's Disease: a Review. ChemMedChem 2019; 14:1467-1483. [PMID: 31310701 DOI: 10.1002/cmdc.201900299] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2019] [Revised: 07/05/2019] [Indexed: 12/15/2022]
Abstract
Among neurodegenerative disorders, Alzheimer's disease (AD) is the most common type of dementia, and there is an urgent need to discover new and efficacious forms of treatment for it. Pathological patterns of AD include cholinergic dysfunction, increased β-amyloid (Aβ) peptide concentration, the appearance of neurofibrillary tangles, among others, all of which are strongly associated with specific biological targets. Interactions observed between these targets and potential drug candidates in AD most often occur by competitive mechanisms driven by orthosteric ligands that sometimes result in the production of side effects. In this context, the allosteric mechanism represents a key strategy; this can be regarded as the selective modulation of such targets by allosteric modulators in an advantageous manner, as this may decrease the likelihood of side effects. The purpose of this review is to present an overview of compounds that act as allosteric modulators of the main biological targets related to AD.
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Affiliation(s)
- Guilherme Martins Silva
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Av. do Café, s/n, 14040-903, Ribeirão Preto, Brazil.,Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Av. Bandeirantes, 3900, 14090-901, Ribeirão Preto, Brazil
| | - Mariana Pegrucci Barcelos
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Av. do Café, s/n, 14040-903, Ribeirão Preto, Brazil.,Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Av. Bandeirantes, 3900, 14090-901, Ribeirão Preto, Brazil
| | - João Gabriel Curtolo Poiani
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Av. do Café, s/n, 14040-903, Ribeirão Preto, Brazil
| | - Lorane Izabel da Silva Hage-Melim
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Av. do Café, s/n, 14040-903, Ribeirão Preto, Brazil.,Departamento de Ciências Biológicas e da Saúde, Curso de Farmácia, Universidade Federal do Amapá, Rod. Juscelino Kubitschek, KM-02, 68903-419, Macapá, Brazil
| | - Carlos Henrique Tomich de Paula da Silva
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Av. do Café, s/n, 14040-903, Ribeirão Preto, Brazil.,Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Av. Bandeirantes, 3900, 14090-901, Ribeirão Preto, Brazil
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29
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Liao VWY, Chua HC, Kowal NM, Chebib M, Balle T, Ahring PK. Concatenated γ-aminobutyric acid type A receptors revisited: Finding order in chaos. J Gen Physiol 2019; 151:798-819. [PMID: 30988061 PMCID: PMC6572006 DOI: 10.1085/jgp.201812133] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Accepted: 03/20/2019] [Indexed: 12/19/2022] Open
Abstract
Subunit concatenation is a powerful technique used to control the assembly of structurally diverse heteromeric receptors such as GABAARs. Liao et al. find that existing GABAAR concatemers do not assemble as expected and describe refinements that allow expression of uniform receptor populations. γ-aminobutyric acid type A receptors (GABAARs), the major inhibitory neurotransmitter receptors in the mammalian central nervous system, are arguably the most challenging member of the pentameric Cys-loop receptors to study due to their heteromeric structure. When two or more subunits are expressed together in heterologous systems, receptors of variable subunit type, ratio, and orientation can form, precluding accurate interpretation of data from functional studies. Subunit concatenation is a technique that involves the linking of individual subunits and in theory allows the precise control of the uniformity of expressed receptors. In reality, the resulting concatemers from widely used constructs are flexible in their orientation and may therefore assemble with themselves or free GABAAR subunits in unexpected ways. In this study, we examine functional responses of receptors from existing concatenated constructs and describe refinements necessary to allow expression of uniform receptor populations. We find that dimers from two commonly used concatenated constructs, β-23-α and α-10-β, assemble readily in both the clockwise and the counterclockwise orientations when coexpressed with free subunits. Furthermore, we show that concatemers formed from new tetrameric α-10-β-α-β and α-10-β-α-γ constructs also assemble in both orientations with free subunits to give canonical αβγ receptors. To restrict linker flexibility, we systematically shorten linker lengths of dimeric and pentameric constructs and find optimized constructs that direct the assembly of GABAARs only in one orientation, thus eliminating the ambiguity associated with previously described concatemers. Based on our data, we revisit some noncanonical GABAAR configurations proposed in recent years and explain how the use of some concatenated constructs may have led to wrong conclusions. Our results help clarify current contradictions in the literature regarding GABAAR subunit stoichiometry and arrangement. The lessons learned from this study may guide future efforts in understanding other related heteromeric receptors.
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Affiliation(s)
- Vivian Wan Yu Liao
- The University of Sydney, Brain and Mind Centre, School of Pharmacy, Faculty of Medicine and Health, Camperdown, New South Wales, Australia
| | - Han Chow Chua
- The University of Sydney, Brain and Mind Centre, School of Pharmacy, Faculty of Medicine and Health, Camperdown, New South Wales, Australia
| | - Natalia Magdalena Kowal
- The University of Sydney, Brain and Mind Centre, School of Pharmacy, Faculty of Medicine and Health, Camperdown, New South Wales, Australia.,Faculty of Pharmaceutical Sciences, School of Health Sciences, University of Iceland, Reykjavik, Iceland
| | - Mary Chebib
- The University of Sydney, Brain and Mind Centre, School of Pharmacy, Faculty of Medicine and Health, Camperdown, New South Wales, Australia
| | - Thomas Balle
- The University of Sydney, Brain and Mind Centre, School of Pharmacy, Faculty of Medicine and Health, Camperdown, New South Wales, Australia
| | - Philip Kiær Ahring
- The University of Sydney, Brain and Mind Centre, School of Pharmacy, Faculty of Medicine and Health, Camperdown, New South Wales, Australia
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Moerke MJ, McMahon LR. Nicotine-like discriminative stimulus effects of acetylcholinesterase inhibitors and a muscarinic receptor agonist in Rhesus monkeys. Drug Dev Ind Pharm 2019; 45:861-867. [PMID: 30712397 DOI: 10.1080/03639045.2019.1578787] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Acetylcholinesterase (AChE) inhibitors and positive allosteric nicotinic acetylcholine receptor (nAChR) modulators are potential pharmacotherapies for nicotine dependence. Because some smoking cessation aids (e.g. varenicline) appear to work by mimicking the effects of nicotine, we used drug discrimination to examine whether AChE inhibitors and nAChR allosteric modulators mimic the effects of nicotine. Rhesus monkeys discriminated 1.78 mg/kg of nicotine s.c. under an FR5 schedule of stimulus-shock termination. Nicotine and the AChE inhibitors donepezil and galantamine dose-dependently increased responding on the nicotine-appropriate lever with ED50 values of 0.35, 0.22, and 0.77 mg/kg, respectively. Donepezil (0.56 mg/kg) produced nicotine-like effects for at least 6 h, whereas the duration of action of galantamine (1.78 mg/kg) was less than 3 h. The positive allosteric nAChR modulator PNU-120596 (up to 10 mg/kg) and midazolam (up to 1.0 mg/kg) produced no more than 22% nicotine-lever responding. Oxotremorine, a muscarinic acetylcholine receptor agonist that was used to explore the extent to which muscarinic receptor agonism might contribute to the effects of AChE inhibitors, produced 94% nicotine-lever responding (ED50 value 0.013 mg/kg). The muscarinic antagonist atropine significantly antagonized the effects of both oxotremorine and nicotine; however, the dose of atropine antagonizing oxotremorine was smaller than the dose required to antagonize nicotine. Collectively, these results suggest that AChE inhibitors can mimic the effects of nicotine by indirectly stimulating both nicotinic and muscarinic receptors. Inasmuch as some smoking cessation aids work by exerting nicotine-like effects, the current results are consistent with the potential use of AChE inhibitors as novel smoking cessation aids.
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Affiliation(s)
- Megan J Moerke
- a Department of Pharmacodynamics , College of Pharmacy, University of Florida , Gainesville , FL , USA
| | - Lance R McMahon
- a Department of Pharmacodynamics , College of Pharmacy, University of Florida , Gainesville , FL , USA
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31
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Novel Approach for the Search for Chemical Scaffolds with Dual Activity with Acetylcholinesterase and the α7 Nicotinic Acetylcholine Receptor-A Perspective for the Treatment of Neurodegenerative Disorders. Molecules 2019; 24:molecules24030446. [PMID: 30691196 PMCID: PMC6384821 DOI: 10.3390/molecules24030446] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Revised: 01/23/2019] [Accepted: 01/23/2019] [Indexed: 01/29/2023] Open
Abstract
Neurodegenerative disorders, including Alzheimer’s disease, belong to the group of the most difficult and challenging conditions with very limited treatment options. Attempts to find new drugs in most cases fail at the clinical stage. New tactics to develop better drug candidates to manage these diseases are urgently needed. It is evident that better understanding of the neurodegeneration process is required and targeting multiple receptors may be essential. Herein, we present a novel approach, searching for dual active compounds interacting with acetylcholinesterase (AChE) and the α7 nicotinic acetylcholine receptor (nAChR) using computational chemistry methods including homology modelling and high throughput virtual screening. Activities of identified hits were evaluated at the two targets using the colorimetric method of Ellman and two-electrode voltage-clamp electrophysiology, respectively. Out of 87,250 compounds from a ZINC database of natural products and their derivatives, we identified two compounds, 8 and 9, with dual activity and balanced IC50 values of 10 and 5 µM at AChE, and 34 and 14 µM at α7 nAChR, respectively. This is the first report presenting successful use of virtual screening in finding compounds with dual mode of action inhibiting both the AChE enzyme and the α7 nAChR and shows that computational methods can be a valuable tool in the early lead discovery process.
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32
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Kowal NM, Ahring PK, Liao VWY, Indurti DC, Harvey BS, O'Connor SM, Chebib M, Olafsdottir ES, Balle T. Galantamine is not a positive allosteric modulator of human α4β2 or α7 nicotinic acetylcholine receptors. Br J Pharmacol 2018; 175:2911-2925. [PMID: 29669164 DOI: 10.1111/bph.14329] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Revised: 03/13/2018] [Accepted: 03/15/2018] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND AND PURPOSE The alkaloid galantamine was originally isolated from the green snowdrop Galanthus woronowii and is currently marketed as a drug for treatment of mild to moderate dementia in patients with Alzheimer's disease. In addition to a well-documented proficiency to inhibit acetylcholinesterase, galantamine has been reported to increase neuronal nicotinic ACh (nACh) receptor function by acting as a positive allosteric modulator. Yet there remains controversy regarding these findings in the literature. To resolve this conundrum, we evaluated galantamine actions at α4β2 and α7, which represent the nACh receptors most commonly associated with mammalian cognitive domains. EXPERIMENTAL APPROACH α4β2 [in (α4)3 (β2)2 and (α4)2 (β2)3 stoichiometries] and α7 nACh receptors were expressed in Xenopus laevis oocytes and subjected to two-electrode voltage-clamp electrophysiological experiments. Galantamine (10 nM to 100 μM) was evaluated for direct agonist effects and for positive modulation by co-application with sub-maximally efficacious concentrations of ACh. In addition, similar experiments were performed with α7 nACh receptors stably expressed in HEK293 cells using patch-clamp electrophysiology. KEY RESULTS In concentrations ranging from 10 nM to 1 μM, galantamine did not display direct agonism nor positive modulatory effects at any receptor combination tested. At concentrations from 10 μM and above, galantamine inhibited the activity with a mechanism of action consistent with open-channel pore blockade at all receptor types. CONCLUSION AND IMPLICATIONS Based on our data, we conclude that galantamine is not a positive allosteric modulator of α7 or α4β2 receptors, which represent the majority of nACh receptors in mammalian brain.
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Affiliation(s)
- Natalia M Kowal
- Sydney School of Pharmacy, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, 2006, Australia.,Faculty of Pharmaceutical Sciences, School of Health Sciences, University of Iceland, Reykjavik, IS-107, Iceland
| | - Philip K Ahring
- Sydney School of Pharmacy, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, 2006, Australia
| | - Vivian W Y Liao
- Sydney School of Pharmacy, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, 2006, Australia
| | - Dinesh C Indurti
- Sydney School of Pharmacy, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, 2006, Australia
| | | | | | - Mary Chebib
- Sydney School of Pharmacy, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, 2006, Australia
| | - Elin S Olafsdottir
- Faculty of Pharmaceutical Sciences, School of Health Sciences, University of Iceland, Reykjavik, IS-107, Iceland
| | - Thomas Balle
- Sydney School of Pharmacy, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, 2006, Australia
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