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Taha M, Houchat JN, Taillebois E, Thany SH. The calcium-calmodulin-dependent protein kinase kinase inhibitor, STO-609, inhibits nicotine-induced currents and intracellular calcium increase in insect neurosecretory cells. J Neurochem 2024; 168:1281-1296. [PMID: 38339787 DOI: 10.1111/jnc.16077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Revised: 01/24/2024] [Accepted: 01/25/2024] [Indexed: 02/12/2024]
Abstract
Insect neuronal nicotinic acetylcholine receptors (nAChRs) are transmembrane receptors that play a key role in the development and synaptic plasticity of both vertebrates and invertebrates and are considered to be major targets of neonicotinoid insecticides. We used dorsal unpaired median (DUM) neurons, which are insect neurosecretory cells, in order to explore the intracellular mechanisms leading to the regulation of insect neuronal nAChRs in more detail. Using whole-cell patch-clamp and fura-2AM calcium imaging techniques, we found that a novel CaMKK/AMPK pathway could be involved in the intracellular regulation of DUM neuron nAChRs. The CaMKK selective inhibitor, STO, reduced nicotinic current amplitudes, and strongly when co-applied with α-Bgt. Interestingly, intracellular application of the AMPK activator, A-76, prevented the reduction in nicotine-induced currents observed in the presence of the AMPK inhibitor, dorsomorphin. STO prevented the increase in intracellular calcium induced by nicotine, which was not dependent on α-Bgt. Currents induced by 1 mM LMA, a selective activator of nAChR2, were reduced under bath application of STO, and mecamylamine, which blocked nAChR2 subtype, inhibited the increase in intracellular calcium induced by LMA. These findings provide insight into potential complex mechanisms linked to the modulation of the DUM neuron nAChRs and CaMKK pathway.
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Affiliation(s)
- Maria Taha
- Laboratoire Physiologie, Ecologie et Environnement (P2E), USC-INRAE 1328, Université d'Orléans, Orléans, France
| | - Jean-Noël Houchat
- Laboratoire Physiologie, Ecologie et Environnement (P2E), USC-INRAE 1328, Université d'Orléans, Orléans, France
| | - Emiliane Taillebois
- Laboratoire Physiologie, Ecologie et Environnement (P2E), USC-INRAE 1328, Université d'Orléans, Orléans, France
| | - Steeve H Thany
- Laboratoire Physiologie, Ecologie et Environnement (P2E), USC-INRAE 1328, Université d'Orléans, Orléans, France
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2
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Ramirez-Cando LJ, Rodríguez-Cazar LG, Acosta-Tobar LA, Ballaz SJ. Molecular docking analysis of chlorpyrifos at the human α7-nAChR and its potential relationship with neurocytoxicity in SH-SY5Y cells. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART. B, PESTICIDES, FOOD CONTAMINANTS, AND AGRICULTURAL WASTES 2024; 59:277-284. [PMID: 38600794 DOI: 10.1080/03601234.2024.2340929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2024] [Accepted: 04/03/2024] [Indexed: 04/12/2024]
Abstract
The organophosphate insecticide chlorpyrifos (CPF), an acetylcholinesterase inhibitor, has raised serious concerns about human safety. Apart from inducing synaptic acetylcholine accumulation, CPF could also act at nicotinic acetylcholine receptors, like the α7-isoform (α7-nAChR), which could potentially be harmful to developing brains. Our aims were to use molecular docking to assess the binding interactions between CPF and α7-nAChR through, to test the neurocytotoxic and oxidative effects of very low concentrations of CPF on SH-SY5Y cells, and to hypothesize about the potential mediation of α7-nAChR. Docking analysis showed a significant binding affinity of CPH for the E fragment of the α7-nAChR (ΔGibbs: -5.63 to -6.85 Kcal/mol). According to the MTT- and Trypan Blue-based viability assays, commercial CPF showed concentration- and time-dependent neurotoxic effects at a concentration range (2.5-20 µM), ten-folds lower than those reported to have crucial effects for sheer CPF. A rise of the production of radical oxygen species (ROS) was seen at even lower concentrations (1-2.5 µM) of CPF after 24h. Notably, our docking analysis supports the antagonistic actions of CPF on α7-nAChR that were recently published. In conclusion, while α7-nAChR is responsible for neuronal survival and neurodevelopmental processes, its activity may also mediate the neurotoxicity of CPF.
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Affiliation(s)
- Lenin J Ramirez-Cando
- School of Biological Sciences & Engineering, Universidad Yachay Tech, Urcuquí, Ecuador
| | | | - Luis A Acosta-Tobar
- School of Biological Sciences & Engineering, Universidad Yachay Tech, Urcuquí, Ecuador
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3
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Guzman-Vallejos MS, Ramirez-Cando LJ, Aguayo L, Ballaz SJ. Molecular Docking Analysis at the Human α7-nAChR and Proliferative and Evoked-Calcium Changes in SH-SY5Y Cells by Imidacloprid and Acetamiprid Insecticides. Neurotox Res 2024; 42:16. [PMID: 38376791 DOI: 10.1007/s12640-024-00697-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Revised: 01/24/2024] [Accepted: 02/14/2024] [Indexed: 02/21/2024]
Abstract
Acetamiprid (ACE) and Imidacloprid (IMI) are widely-used neonicotinoid insecticides (NNIs) with functional activity at human acetylcholine nicotinic receptors and, therefore, with putative toxic effects. The objective of this study was the evaluation of the interactions between NNIs and α7-nAChR, as this receptor keeps intracellular Ca2+ ([Ca2+]i) to an optimum for an adequate neuronal functioning. Possible interactions between NNIs and the cryo-EM structure of the human α-7 nAChR were identified by molecular docking. Additionally, NNI effects were analyzed in neuroblastoma SH-SY5Y cells, as they naturally express α-7 nAChRs. Functional studies included proliferative/cytotoxic effects (MTT test) in undifferentiated SH-SY-5Y cells and indirect measurements of [Ca2+]i transients in retinoic acid-differentiated SH-SY-5Y cells loaded with Fluo-4 AM. Docking analysis showed that the binding of IMI and ACE occurred at the same aromatic cage that the specific α-7 nAChR agonist EVP-6124. IMI showed a better docking strength than ACE. According to the MTT assays, low doses (10-50 µM) of IMI better than ACE stimulated neuroblastoma cell proliferation. At higher doses (250-500 µM), IMI also prevailed over ACE and dose-dependently triggered more abrupt fluorescence changes due to [Ca2+]i mobilization in differentiated SH-SY5Y neurons. Indeed, only IMI blunted nicotine-evoked intracellular fluorescence stimulation (i.e., nicotine cross-desensitization). Summarizing, IMI demonstrated a superior docking strength and more robust cellular responses compared to ACE, which were likely associated with a stronger activity at α-7nAChRs. Through the interaction with α-7nAChRs, IMI would demonstrate its high neurotoxic potential for humans. More research is needed for investigating the proliferative effects of IMI in neuroblastoma cells.
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Affiliation(s)
| | - Lenin J Ramirez-Cando
- School of Biological Sciences & Engineering, Universidad Yachay Tech, Urcuquí, Ecuador
| | - Luis Aguayo
- School of Biological Sciences, Universidad de Concepcion, Concepción, Chile
| | - Santiago J Ballaz
- School of Medicine, Universidad Espíritu Santo, Ave. Samborondón 5, Samborondón, 0901952, Ecuador.
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4
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Salim C, Batsaikhan E, Kan AK, Chen H, Jee C. Nicotine Motivated Behavior in C. elegans. Int J Mol Sci 2024; 25:1634. [PMID: 38338915 PMCID: PMC10855306 DOI: 10.3390/ijms25031634] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Revised: 01/20/2024] [Accepted: 01/22/2024] [Indexed: 02/12/2024] Open
Abstract
To maximize the advantages offered by Caenorhabditis elegans as a high-throughput (HTP) model for nicotine dependence studies, utilizing its well-defined neuroconnectome as a robust platform, and to unravel the genetic basis of nicotine-motivated behaviors, we established the nicotine conditioned cue preference (CCP) paradigm. Nicotine CCP enables the assessment of nicotine preference and seeking, revealing a parallel to fundamental aspects of nicotine-dependent behaviors observed in mammals. We demonstrated that nicotine-elicited cue preference in worms is mediated by nicotinic acetylcholine receptors and requires dopamine for CCP development. Subsequently, we pinpointed nAChR subunits associated with nicotine preference and validated human GWAS candidates linked to nicotine dependence involved in nAChRs. Functional validation involves assessing the loss-of-function strain of the CACNA2D3 ortholog and the knock-out (KO) strain of the CACNA2D2 ortholog, closely related to CACNA2D3 and sharing human smoking phenotypes. Our orthogonal approach substantiates the functional conservation of the α2δ subunit of the calcium channel in nicotine-motivated behavior. Nicotine CCP in C. elegans serves as a potent affirmation of the cross-species functional relevance of GWAS candidate genes involved in nicotine seeking associated with tobacco abuse, providing a streamlined yet comprehensive system for investigating intricate behavioral paradigms within a simplified and reliable framework.
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Affiliation(s)
| | | | | | | | - Changhoon Jee
- Department of Pharmacology, Addiction Science and Toxicology, College of Medicine, University of Tennessee Health Science Center, Memphis, TN 38163, USA; (C.S.)
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Sinclair P, Kabbani N. Ionotropic and metabotropic responses by alpha 7 nicotinic acetylcholine receptors. Pharmacol Res 2023; 197:106975. [PMID: 38032294 DOI: 10.1016/j.phrs.2023.106975] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Revised: 10/12/2023] [Accepted: 10/26/2023] [Indexed: 12/01/2023]
Abstract
Nicotinic acetylcholine receptors (nAChRs) belong to a superfamily of cys-loop receptors characterized by the assembly of five subunits into a multi-protein channel complex. Ligand binding to nAChRs activates rapid allosteric transitions of the receptor leading to channel opening and ion flux in neuronal and non-neuronal cell. Thus, while ionotropic properties of nAChRs are well recognized, less is known about ligand-mediated intracellular metabotropic signaling responses. Studies in neural and non-neural cells confirm ionotropic and metabotropic channel responses following ligand binding. In this review we summarize evidence on the existence of ionotropic and metabotropic signaling responses by homopentameric α7 nAChRs in various cell types. We explore how coordinated calcium entry through the ion channel and calcium release from nearby stores gives rise to signaling important for the modulation of cytoskeletal motility and cell growth. Amino acid residues for intracellular protein binding within the α7 nAChR support engagement in metabotropic responses including signaling through heterotrimeric G proteins in neural and immune cells. Understanding the dual properties of ionotropic and metabotropic nAChR responses is essential in advancing drug development for the treatment of various human disease.
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Affiliation(s)
| | - Nadine Kabbani
- Interdisciplinary Program in Neuroscience, Fairfax, VA, USA; School of Systems Biology, George Mason University, Fairfax, VA, USA.
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6
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Petsakou A, Liu Y, Liu Y, Comjean A, Hu Y, Perrimon N. Cholinergic neurons trigger epithelial Ca 2+ currents to heal the gut. Nature 2023; 623:122-131. [PMID: 37722602 PMCID: PMC10699467 DOI: 10.1038/s41586-023-06627-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Accepted: 09/08/2023] [Indexed: 09/20/2023]
Abstract
A fundamental and unresolved question in regenerative biology is how tissues return to homeostasis after injury. Answering this question is essential for understanding the aetiology of chronic disorders such as inflammatory bowel diseases and cancer1. We used the Drosophila midgut2 to investigate this and discovered that during regeneration a subpopulation of cholinergic3 neurons triggers Ca2+ currents among intestinal epithelial cells, the enterocytes, to promote return to homeostasis. We found that downregulation of the conserved cholinergic enzyme acetylcholinesterase4 in the gut epithelium enables acetylcholine from specific Egr5 (TNF in mammals)-sensing cholinergic neurons to activate nicotinic receptors in innervated enterocytes. This activation triggers high Ca2+, which spreads in the epithelium through Innexin2-Innexin7 gap junctions6, promoting enterocyte maturation followed by reduction of proliferation and inflammation. Disrupting this process causes chronic injury consisting of ion imbalance, Yki (YAP in humans) activation7, cell death and increase of inflammatory cytokines reminiscent of inflammatory bowel diseases8. Altogether, the conserved cholinergic pathway facilitates epithelial Ca2+ currents that heal the intestinal epithelium. Our findings demonstrate nerve- and bioelectric9-dependent intestinal regeneration and advance our current understanding of how a tissue returns to homeostasis after injury.
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Affiliation(s)
| | - Yifang Liu
- Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Ying Liu
- Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Aram Comjean
- Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Yanhui Hu
- Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Norbert Perrimon
- Department of Genetics, Harvard Medical School, Boston, MA, USA.
- Howard Hughes Medical Institute, Boston, MA, USA.
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7
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Lai JIC, Porcu A, Romoli B, Keisler M, Manfredsson FP, Powell SB, Dulcis D. Nicotine-Mediated Recruitment of GABAergic Neurons to a Dopaminergic Phenotype Attenuates Motor Deficits in an Alpha-Synuclein Parkinson's Model. Int J Mol Sci 2023; 24:4204. [PMID: 36835612 PMCID: PMC9960650 DOI: 10.3390/ijms24044204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 02/11/2023] [Accepted: 02/14/2023] [Indexed: 02/22/2023] Open
Abstract
Previous work revealed an inverse correlation between tobacco smoking and Parkinson's disease (PD) that is associated with nicotine-induced neuroprotection of dopaminergic (DA) neurons against nigrostriatal damage in PD primates and rodent models. Nicotine, a neuroactive component of tobacco, can directly alter the activity of midbrain DA neurons and induce non-DA neurons in the substantia nigra (SN) to acquire a DA phenotype. Here, we investigated the recruitment mechanism of nigrostriatal GABAergic neurons to express DA phenotypes, such as transcription factor Nurr1 and DA-synthesizing enzyme tyrosine hydroxylase (TH), and the concomitant effects on motor function. Wild-type and α-syn-overexpressing (PD) mice treated with chronic nicotine were assessed by behavioral pattern monitor (BPM) and immunohistochemistry/in situ hybridization to measure behavior and the translational/transcriptional regulation of neurotransmitter phenotype following selective Nurr1 overexpression or DREADD-mediated chemogenetic activation. We found that nicotine treatment led to a transcriptional TH and translational Nurr1 upregulation within a pool of SN GABAergic neurons in wild-type animals. In PD mice, nicotine increased Nurr1 expression, reduced the number of α-syn-expressing neurons, and simultaneously rescued motor deficits. Hyperactivation of GABA neurons alone was sufficient to elicit de novo translational upregulation of Nurr1. Retrograde labeling revealed that a fraction of these GABAergic neurons projects to the dorsal striatum. Finally, concomitant depolarization and Nurr1 overexpression within GABA neurons were sufficient to mimic nicotine-mediated dopamine plasticity. Revealing the mechanism of nicotine-induced DA plasticity protecting SN neurons against nigrostriatal damage could contribute to developing new strategies for neurotransmitter replacement in PD.
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Affiliation(s)
- Jessica IChi Lai
- Department of Psychiatry, University of California San Diego, La Jolla, CA 92093, USA
| | - Alessandra Porcu
- Department of Psychiatry, University of California San Diego, La Jolla, CA 92093, USA
- Department of Drug Discovery and Biomedical Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Benedetto Romoli
- Department of Psychiatry, University of California San Diego, La Jolla, CA 92093, USA
| | - Maria Keisler
- Department of Psychiatry, University of California San Diego, La Jolla, CA 92093, USA
| | | | - Susan B. Powell
- Department of Psychiatry, University of California San Diego, La Jolla, CA 92093, USA
| | - Davide Dulcis
- Department of Psychiatry, University of California San Diego, La Jolla, CA 92093, USA
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8
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Recent Advances in the Discovery of Nicotinic Acetylcholine Receptor Allosteric Modulators. Molecules 2023; 28:molecules28031270. [PMID: 36770942 PMCID: PMC9920195 DOI: 10.3390/molecules28031270] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 01/18/2023] [Accepted: 01/26/2023] [Indexed: 01/31/2023] Open
Abstract
Positive allosteric modulators (PAMs), negative allosteric modulators (NAMs), silent agonists, allosteric activating PAMs and neutral or silent allosteric modulators are compounds capable of modulating the nicotinic receptor by interacting at allosteric modulatory sites distinct from the orthosteric sites. This survey is focused on the compounds that have been shown or have been designed to interact with nicotinic receptors as allosteric modulators of different subtypes, mainly α7 and α4β2. Minimal chemical changes can cause a different pharmacological profile, which can then lead to the design of selective modulators. Experimental evidence supports the use of allosteric modulators as therapeutic tools for neurological and non-neurological conditions.
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9
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Lv C, Sun M, Guo Y, Xia W, Qiao S, Tao Y, Fang Y, Zhang Q, Zhu Y, Yalikun Y, Xia Y, Wei Z, Dai Y. Cholinergic dysfunction-induced insufficient activation of alpha7 nicotinic acetylcholine receptor drives the development of rheumatoid arthritis through promoting protein citrullination via the SP3/PAD4 pathway. Acta Pharm Sin B 2023; 13:1600-1615. [PMID: 37139415 PMCID: PMC10150100 DOI: 10.1016/j.apsb.2023.01.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Revised: 10/10/2022] [Accepted: 11/23/2022] [Indexed: 01/19/2023] Open
Abstract
Both cholinergic dysfunction and protein citrullination are the hallmarks of rheumatoid arthritis (RA), but the relationship between the two phenomena remains unclear. We explored whether and how cholinergic dysfunction accelerates protein citrullination and consequently drives the development of RA. Cholinergic function and protein citrullination levels in patients with RA and collagen-induced arthritis (CIA) mice were collected. In both neuron-macrophage coculture system and CIA mice, the effect of cholinergic dysfunction on protein citrullination and expression of peptidylarginine deiminases (PADs) was assessed by immunofluorescence. The key transcription factors for PAD4 expression were predicted and validated. Cholinergic dysfunction in the patients with RA and CIA mice negatively correlated with the degree of protein citrullination in synovial tissues. The cholinergic or alpha7 nicotinic acetylcholine receptor (α7nAChR) deactivation and activation resulted in the promotion and reduction of protein citrullination in vitro and in vivo, respectively. Especially, the activation deficiency of α7nAChR induced the earlier onset and aggravation of CIA. Furthermore, deactivation of α7nAChR increased the expression of PAD4 and specificity protein-3 (SP3) in vitro and in vivo. Our results suggest that cholinergic dysfunction-induced deficient α7nAChR activation, which induces the expression of SP3 and its downstream molecule PAD4, accelerating protein citrullination and the development of RA.
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Affiliation(s)
- Changjun Lv
- Department of Pharmacology of Chinese Materia Medica, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing 211198, China
| | - Minghui Sun
- Division of Sports Medicine and Adult Reconstructive Surgery, Department of Orthopedic Surgery, Nanjing Drum Tower Hospital, the Affiliated Hospital of Nanjing University Medical School, Nanjing 210008, China
| | - Yilei Guo
- Department of Pharmacology of Chinese Materia Medica, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing 211198, China
| | - Wenxin Xia
- Department of Pharmacology of Chinese Materia Medica, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing 211198, China
| | - Simiao Qiao
- Department of Pharmacology of Chinese Materia Medica, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing 211198, China
| | - Yu Tao
- Department of Pharmacology of Chinese Materia Medica, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing 211198, China
| | - Yulai Fang
- Department of Pharmacology of Chinese Materia Medica, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing 211198, China
| | - Qin Zhang
- Department of Pharmacology of Chinese Materia Medica, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing 211198, China
| | - Yanrong Zhu
- Department of Pharmacology of Chinese Materia Medica, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing 211198, China
| | - Yusufu Yalikun
- Division of Sports Medicine and Adult Reconstructive Surgery, Department of Orthopedic Surgery, Nanjing Drum Tower Hospital, the Affiliated Hospital of Nanjing University Medical School, Nanjing 210008, China
| | - Yufeng Xia
- Department of Pharmacology of Chinese Materia Medica, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing 211198, China
| | - Zhifeng Wei
- Department of Pharmacology of Chinese Materia Medica, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing 211198, China
- Corresponding authors.
| | - Yue Dai
- Department of Pharmacology of Chinese Materia Medica, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing 211198, China
- Corresponding authors.
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10
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Cannabidiol as a modulator of α7 nicotinic receptors. Cell Mol Life Sci 2022; 79:564. [DOI: 10.1007/s00018-022-04600-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2022] [Revised: 09/29/2022] [Accepted: 10/14/2022] [Indexed: 11/03/2022]
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11
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Guerreiro I, Gu Z, Yakel JL, Gutkin BS. Recurring Cholinergic Inputs Induce Local Hippocampal Plasticity through Feedforward Disinhibition. eNeuro 2022; 9:ENEURO.0389-21.2022. [PMID: 36028329 PMCID: PMC9463983 DOI: 10.1523/eneuro.0389-21.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 04/22/2022] [Accepted: 05/15/2022] [Indexed: 11/30/2022] Open
Abstract
The CA1 pyramidal neurons are embedded in an intricate local circuitry that contains a variety of interneurons. The roles these interneurons play in the regulation of the excitatory synaptic plasticity remains largely understudied. Recent experiments showed that recurring cholinergic activation of α7 nACh receptors expressed in oriens-lacunosum-moleculare (OLMα2) interneurons can directly induce LTP in Schaffer collateral (SC)-CA1 synapses. Here, we pair in vitro studies with biophysically based modeling to uncover the underlying mechanisms. According to our model, α7 nAChR activation increases OLM GABAergic activity. This results in the inhibition of the fast-spiking interneurons that provide feedforward inhibition onto CA1 pyramidal neurons. This disinhibition, paired with tightly timed SC stimulation, can induce potentiation at the excitatory synapses of CA1 pyramidal neurons. Our work details the role of cholinergic modulation in disinhibition-induced hippocampal plasticity. It relates the timing of cholinergic pairing found experimentally in previous studies with the timing between disinhibition and hippocampal stimulation necessary to induce potentiation and suggests the dynamics of the involved interneurons play a crucial role in determining this timing.Significance StatementWe use a combination of experiments and mechanistic modeling to uncover the key role for cholinergic neuromodulation of feedforward disinhibitory circuits in regulating hippocampal plasticity. We found that cholinergic activation of α7 nAChR on α7 nACh receptors expressed in oriens-lacunosum-moleculare interneurons, when tightly paired with stimulation of the Schaffer collaterals, can cancel feedforward inhibition onto CA1 pyramidal cells, enabling the potentiation of the SC-CA1 synapse. Our work details how cholinergic action on GABAergic interneurons can tightly regulate the excitability and plasticity of the hippocampal network, unraveling the intricate interplay of the hierarchal inhibitory circuitry and cholinergic neuromodulation as a mechanism for hippocampal plasticity.
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Affiliation(s)
- Inês Guerreiro
- Group for Neural Theory, LNC2 INSERM U960, Département d'études cognitives, Ecole Normale Superieure, PSL Université Paris, 75005 Paris, France
| | - Zhenglin Gu
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC 27709, USA
| | - Jerrel L Yakel
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC 27709, USA
| | - Boris S Gutkin
- Group for Neural Theory, LNC2 INSERM U960, Département d'études cognitives, Ecole Normale Superieure, PSL Université Paris, 75005 Paris, France
- Center for Cognition and Decision Making, Institute for Cognitive Neuroscience, National Research University Higher School of Economics, Moscow 101000, Russia
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12
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Tiepolt S, Meyer PM, Patt M, Deuther-Conrad W, Hesse S, Barthel H, Sabri O. PET Imaging of Cholinergic Neurotransmission in Neurodegenerative Disorders. J Nucl Med 2022; 63:33S-44S. [PMID: 35649648 DOI: 10.2967/jnumed.121.263198] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Revised: 05/06/2022] [Indexed: 12/13/2022] Open
Abstract
As a neuromodulator, the neurotransmitter acetylcholine plays an important role in cognitive, mood, locomotor, sleep/wake, and olfactory functions. In the pathophysiology of most neurodegenerative diseases, such as Alzheimer disease (AD) or Lewy body disorder (LBD), cholinergic receptors, transporters, or enzymes are involved and relevant as imaging targets. The aim of this review is to summarize current knowledge on PET imaging of cholinergic neurotransmission in neurodegenerative diseases. For PET imaging of presynaptic vesicular acetylcholine transporters (VAChT), (-)-18F-fluoroethoxybenzovesamicol (18F-FEOBV) was the first PET ligand that could be successfully translated to clinical application. Since then, the number of 18F-FEOBV PET investigations on patients with AD or LBD has grown rapidly and provided novel, important findings concerning the pathophysiology of AD and LBD. Regarding the α4β2 nicotinic acetylcholine receptors (nAChRs), various second-generation PET ligands, such as 18F-nifene, 18F-AZAN, 18F-XTRA, (-)-18F-flubatine, and (+)-18F-flubatine, were developed and successfully translated to human application. In neurodegenerative diseases such as AD and LBD, PET imaging of α4β2 nAChRs is of special value for monitoring disease progression and drugs directed to α4β2 nAChRs. For PET of α7 nAChR, 18F-ASEM and 11C-MeQAA were successfully applied in mild cognitive impairment and AD, respectively. The highest potential for α7 nAChR PET is seen in staging, in evaluating disease progression, and in therapy monitoring. PET of selective muscarinic acetylcholine receptors (mAChRs) is still in an early stage, as the development of subtype-selective radioligands is complicated. Promising radioligands to image mAChR subtypes M1 (11C-LSN3172176), M2 (18F-FP-TZTP), and M4 (11C-MK-6884) were developed and successfully translated to humans. PET imaging of mAChRs is relevant for the assessment and monitoring of therapies in AD and LBD. PET of acetylcholine esterase activity has been investigated since the 1990s. Many PET studies with 11C-PMP and 11C-MP4A demonstrated cortical cholinergic dysfunction in dementia associated with AD and LBD. Recent studies indicated a solid relationship between subcortical and cortical cholinergic dysfunction and noncognitive dysfunctions such as balance and gait in LBD. Taken together, PET of distinct components of cholinergic neurotransmission is of great interest for diagnosis, disease monitoring, and therapy monitoring and to gain insight into the pathophysiology of different neurodegenerative disorders.
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Affiliation(s)
- Solveig Tiepolt
- Department of Nuclear Medicine, University of Leipzig, Leipzig, Germany; and
| | - Philipp M Meyer
- Department of Nuclear Medicine, University of Leipzig, Leipzig, Germany; and
| | - Marianne Patt
- Department of Nuclear Medicine, University of Leipzig, Leipzig, Germany; and
| | | | - Swen Hesse
- Department of Nuclear Medicine, University of Leipzig, Leipzig, Germany; and
| | - Henryk Barthel
- Department of Nuclear Medicine, University of Leipzig, Leipzig, Germany; and
| | - Osama Sabri
- Department of Nuclear Medicine, University of Leipzig, Leipzig, Germany; and
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13
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Evaluation of the effect of nicotine and O-acetyl-L-carnitine on testosterone-induced spatial learning impairment in Morris water maze and assessment of protein markers. LEARNING AND MOTIVATION 2022. [DOI: 10.1016/j.lmot.2022.101810] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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14
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Sánchez Triviño CA, Landinez MP, Duran S, Gomez MDP, Nasi E. Modulation of Gq/PLC-Mediated Signaling by Acute Lithium Exposure. Front Cell Neurosci 2022; 16:838939. [PMID: 35242014 PMCID: PMC8885521 DOI: 10.3389/fncel.2022.838939] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2021] [Accepted: 01/27/2022] [Indexed: 11/13/2022] Open
Abstract
Although lithium has long been one of the most widely used pharmacological agents in psychiatry, its mechanisms of action at the cellular and molecular levels remain poorly understood. One of the targets of Li+ is the phosphoinositide pathway, but whereas the impact of Li+ on inositol lipid metabolism is well documented, information on physiological effects at the cellular level is lacking. We examined in two mammalian cell lines the effect of acute Li+ exposure on the mobilization of internal Ca2+ and phospholipase C (PLC)-dependent membrane conductances. We first corroborated by Western blots and immunofluorescence in HEK293 cells the presence of key signaling elements of a muscarinic PLC pathway (M1AchR, Gq, PLC-β1, and IP3Rs). Stimulation with carbachol evoked a dose-dependent mobilization of Ca, as determined with fluorescent indicators. This was due to release from internal stores and proved susceptible to the PLC antagonist U73122. Li+ exposure reproducibly potentiated the Ca response in a concentration-dependent manner extending to the low millimolar range. To broaden those observations to a neuronal context and probe potential Li modulation of electrical signaling, we next examined the cell line SHsy5y. We replicated the potentiating effects of Li on the mobilization of internal Ca, and, after characterizing the basic properties of the electrical response to cholinergic stimulation, we also demonstrated an equally robust upregulation of muscarinic membrane currents. Finally, by directly stimulating the signaling pathway at different links downstream of the receptor, the site of action of the observed Li effects could be narrowed down to the G protein and its interaction with PLC-β. These observations document a modulation of Gq/PLC/IP3-mediated signaling by acute exposure to lithium, reflected in distinct physiological changes in cellular responses.
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Affiliation(s)
- Cesar Adolfo Sánchez Triviño
- Departamento de Biología, Universidad Nacional de Colombia, Bogotá, Colombia
- Centro Internacional de Física, Universidad Nacional de Colombia, Bogotá, Colombia
| | - Maria Paula Landinez
- Departamento de Biología, Universidad Nacional de Colombia, Bogotá, Colombia
- Centro Internacional de Física, Universidad Nacional de Colombia, Bogotá, Colombia
| | - Sara Duran
- Departamento de Biología, Universidad Nacional de Colombia, Bogotá, Colombia
- Centro Internacional de Física, Universidad Nacional de Colombia, Bogotá, Colombia
| | - María Del Pilar Gomez
- Departamento de Biología, Universidad Nacional de Colombia, Bogotá, Colombia
- Marine Biological Laboratory, Woods Hole, MA, United States
| | - Enrico Nasi
- Marine Biological Laboratory, Woods Hole, MA, United States
- Instituto de Genética, Universidad Nacional de Colombia, Bogotá, Colombia
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15
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Borroni V, Barrantes FJ. Homomeric and Heteromeric α7 Nicotinic Acetylcholine Receptors in Health and Some Central Nervous System Diseases. MEMBRANES 2021; 11:membranes11090664. [PMID: 34564481 PMCID: PMC8465519 DOI: 10.3390/membranes11090664] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 08/24/2021] [Accepted: 08/24/2021] [Indexed: 11/22/2022]
Abstract
Nicotinic acetylcholine receptors (nAChRs) are pentameric ligand-gated ion channels involved in the modulation of essential brain functions such as memory, learning, and attention. Homomeric α7 nAChR, formed exclusively by five identical α7 subunits, is involved in rapid synaptic transmission, whereas the heteromeric oligomers composed of α7 in combination with β subunits display metabotropic properties and operate in slower time frames. At the cellular level, the activation of nAChRs allows the entry of Na+ and Ca2+; the two cations depolarize the membrane and trigger diverse cellular signals, depending on the type of nAChR pentamer and neurons involved, the location of the intervening cells, and the networks of which these neuronal cells form part. These features make the α7 nAChR a central player in neurotransmission, metabolically associated Ca2+-mediated signaling, and modulation of diverse fundamental processes operated by other neurotransmitters in the brain. Due to its ubiquitous distribution and the multiple functions it displays in the brain, the α7 nAChR is associated with a variety of neurological and neuropsychiatric disorders whose exact etiopathogenic mechanisms are still elusive.
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Affiliation(s)
- Virginia Borroni
- Instituto de Tecnología en Polímeros y Nanotecnología (ITPN-UBA-CONICET), Universidad de Buenos Aires, Ciudad Universitaria, Buenos Aires C1127AAR, Argentina;
| | - Francisco J. Barrantes
- Laboratory of Molecular Neurobiology, Institute for Biomedical Research, UCA–CONICET, Faculty of Medical Sciences, Catholic University of Argentina, Av. Alicia Moreau de Justo 1600, Buenos Aires C1107AAZ, Argentina
- Correspondence:
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16
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Hashemzaei M, Baratzadeh N, Sharamian I, Fanoudi S, Sanati M, Rezaei H, Shahraki J, Rezaee R, Belaran M, Bazi A, Tabrizian K. Intrahippocampal co-administration of nicotine and O-acetyl-L-carnitine prevents the H-89-induced spatial learning deficits in Morris water maze. JOURNAL OF COMPLEMENTARY & INTEGRATIVE MEDICINE 2021; 19:691-696. [PMID: 33964190 DOI: 10.1515/jcim-2021-0035] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Accepted: 03/16/2021] [Indexed: 11/15/2022]
Abstract
OBJECTIVES H-89 (a protein kinase AII [PKA II] inhibitor) impairs the spatial memory in the Morris water maze task in rats. In the present study, we aimed to study the protective effects of nicotine and O-acetyl-L-carnitine against H-89-induced spatial memory deficits. METHODS Spatial memory impairment was induced by the bilateral intrahippocampal administration of 10 µM H-89 (dissolved in dimethyl sulfoxide, DMSO) to rats. The rats then received bilateral administrations of either nicotine (1 μg/μL, dissolved in saline) or O-acetyl-L-carnitine (100 μM/side, dissolved in deionized water) alone and in combination. Control groups received either saline, deionized water, or DMSO. RESULTS The H-89-treated animals showed significant increases in the time and distance travelled to find hidden platforms, and there was also a significant decrease in the time spent in the target quadrant compared to DMSO-treated animals. Nicotine and O-acetyl-L-carnitine had no significant effects on H-89-induced spatial learning impairments alone, but the bilateral intrahippocampal co-administration of nicotine and O-acetyl-L-carnitine prevented H-89-induced spatial learning deficits and increased the time spent in the target quadrant in comparison with H-89-treated animals. CONCLUSIONS Our results indicated the potential synergistic effects of nicotine and O-acetyl-L-carnitine in preventing protein kinase AII inhibitor (H-89)-induced spatial learning impairments.
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Affiliation(s)
- Mahmoud Hashemzaei
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Zabol University of Medical Sciences, Zabol, Iran
| | - Najmeh Baratzadeh
- Students Research Committee, Faculty of Pharmacy, Zabol University of Medical Sciences, Zabol, Iran
| | - Iraj Sharamian
- Pediatric Gastroenterology and Hepatology Research Center, Zabol University of Medical Sciences, Zabol, Iran
| | - Sahar Fanoudi
- Department of Pharmacology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Mehdi Sanati
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran
| | - Hanieh Rezaei
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Zabol University of Medical Sciences, Zabol, Iran
| | - Jafar Shahraki
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Zabol University of Medical Sciences, Zabol, Iran
| | - Ramin Rezaee
- Clinical Research Unit, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Maryam Belaran
- Department of Physiology, Faculty of Medicine, Zabol University of Medical Sciences, Zabol, Iran
| | - Ali Bazi
- Faculty of Allied Medical Sciences, Zabol University of Medical Science, Zabol, Iran
| | - Kaveh Tabrizian
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Zabol University of Medical Sciences, Zabol, Iran
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17
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Structure and gating mechanism of the α7 nicotinic acetylcholine receptor. Cell 2021; 184:2121-2134.e13. [PMID: 33735609 DOI: 10.1016/j.cell.2021.02.049] [Citation(s) in RCA: 119] [Impact Index Per Article: 39.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 01/13/2021] [Accepted: 02/22/2021] [Indexed: 12/13/2022]
Abstract
The α7 nicotinic acetylcholine receptor plays critical roles in the central nervous system and in the cholinergic inflammatory pathway. This ligand-gated ion channel assembles as a homopentamer, is exceptionally permeable to Ca2+, and desensitizes faster than any other Cys-loop receptor. The α7 receptor has served as a prototype for the Cys-loop superfamily yet has proven refractory to structural analysis. We present cryo-EM structures of the human α7 nicotinic receptor in a lipidic environment in resting, activated, and desensitized states, illuminating the principal steps in the gating cycle. The structures also reveal elements that contribute to its function, including a C-terminal latch that is permissive for channel opening, and an anionic ring in the extracellular vestibule that contributes to its high conductance and calcium permeability. Comparisons among the α7 structures provide a foundation for mapping the gating cycle and reveal divergence in gating mechanisms in the Cys-loop receptor superfamily.
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18
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Castillo-Rolón D, Ramírez-Sánchez E, Arenas-López G, Garduño J, Hernández-González O, Mihailescu S, Hernández-López S. Nicotine Increases Spontaneous Glutamate Release in the Rostromedial Tegmental Nucleus. Front Neurosci 2021; 14:604583. [PMID: 33519359 PMCID: PMC7838497 DOI: 10.3389/fnins.2020.604583] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Accepted: 11/23/2020] [Indexed: 01/26/2023] Open
Abstract
The rostromedial tegmental nucleus (RMTg) is a bilateral structure localized in the brainstem and comprise of mainly GABAergic neurons. One of the main functions of the RMTg is to regulate the activity of dopamine neurons of the mesoaccumbens pathway. Therefore, the RMTg has been proposed as a modulator of the reward system and adaptive behaviors associated to reward learning. The RMTg receives an important glutamatergic input from the lateral habenula. Also, it receives cholinergic inputs from the laterodorsal and pedunculopontine tegmental nuclei. Previously, it was reported that nicotine increases glutamate release, evoked by electric stimulation, in the RMTg nucleus. However, the mechanisms by which nicotine induces this effect were not explored. In the present work, we performed electrophysiological experiments in brainstem slices to study the effect of nicotine on spontaneous excitatory postsynaptic currents recorded from immunocytochemically identified RMTg neurons. Also, we used calcium imaging techniques to explore the effects of nicotine on multiple RMTg neurons simultaneously. We found that nicotine promotes the persistent release of glutamate through the activation of α7 nicotinic acetylcholine receptors present on glutamatergic afferents and by a mechanism involving calcium release from intracellular stores. Through these mechanisms, nicotine increases the excitability and synchronizes the activity of RMTg neurons. Our results suggest that the RMTg nucleus mediates the noxious effects of the nicotine, and it could be a potential therapeutic target against tobacco addiction.
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Affiliation(s)
- Diego Castillo-Rolón
- Departamento de Fisiología, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Enrique Ramírez-Sánchez
- Departamento de Fisiología, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Gabina Arenas-López
- Departamento de Fisiología, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Julieta Garduño
- Departamento de Fisiología, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Omar Hernández-González
- Departamento de Fisiología, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Stefan Mihailescu
- Departamento de Fisiología, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Salvador Hernández-López
- Departamento de Fisiología, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
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19
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Ca 2+ Dyshomeostasis Disrupts Neuronal and Synaptic Function in Alzheimer's Disease. Cells 2020; 9:cells9122655. [PMID: 33321866 PMCID: PMC7763805 DOI: 10.3390/cells9122655] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 12/02/2020] [Accepted: 12/07/2020] [Indexed: 02/07/2023] Open
Abstract
Ca2+ homeostasis is essential for multiple neuronal functions and thus, Ca2+ dyshomeostasis can lead to widespread impairment of cellular and synaptic signaling, subsequently contributing to dementia and Alzheimer's disease (AD). While numerous studies implicate Ca2+ mishandling in AD, the cellular basis for loss of cognitive function remains under investigation. The process of synaptic degradation and degeneration in AD is slow, and constitutes a series of maladaptive processes each contributing to a further destabilization of the Ca2+ homeostatic machinery. Ca2+ homeostasis involves precise maintenance of cytosolic Ca2+ levels, despite extracellular influx via multiple synaptic Ca2+ channels, and intracellular release via organelles such as the endoplasmic reticulum (ER) via ryanodine receptor (RyRs) and IP3R, lysosomes via transient receptor potential mucolipin channel (TRPML) and two pore channel (TPC), and mitochondria via the permeability transition pore (PTP). Furthermore, functioning of these organelles relies upon regulated inter-organelle Ca2+ handling, with aberrant signaling resulting in synaptic dysfunction, protein mishandling, oxidative stress and defective bioenergetics, among other consequences consistent with AD. With few effective treatments currently available to mitigate AD, the past few years have seen a significant increase in the study of synaptic and cellular mechanisms as drivers of AD, including Ca2+ dyshomeostasis. Here, we detail some key findings and discuss implications for future AD treatments.
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20
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Takahashi T, Yoshida T, Harada K, Miyagi T, Hashimoto K, Hide I, Tanaka S, Irifune M, Sakai N. Component of nicotine-induced intracellular calcium elevation mediated through α3- and α5-containing nicotinic acetylcholine receptors are regulated by cyclic AMP in SH-SY 5Y cells. PLoS One 2020; 15:e0242349. [PMID: 33253222 PMCID: PMC7703979 DOI: 10.1371/journal.pone.0242349] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Accepted: 11/01/2020] [Indexed: 12/03/2022] Open
Abstract
The pathway from the medial habenular nucleus to the interpeduncular nucleus, in which nicotinic acetylcholine receptor (nAChR) including the α3 and α5 subunits (α3 * and α5 * nAChRs) are expressed, is implicated in nicotine dependence. We investigated whether α3 * and α5 * nAChRs are regulated by cAMP using SH-SY5Y cells to clarify the significance of these receptors in nicotine dependence. We analyzed the nicotine-induced elevation of intracellular Ca2+ ([Ca2+]i). Nicotine induces a concentration-dependent increase in [Ca2+]i. The elimination of Ca2+ from extracellular fluid or intracellular stores demonstrated that the nicotine-induced [Ca2+]i elevation was due to extracellular influx and intracellular mobilization. The effects of tubocurarine on nicotine-induced [Ca2+]i elevation and current suggest that intracellular mobilization is caused by plasma membrane-permeating nicotine. The inhibition of α3 *, α5 *, α7 nAChR and voltage-gated Ca2+ channels by using siRNAs and selective antagonists revealed the involvement of these nAChR subunits and channels in nicotine-induced [Ca2+]i elevation. To distinguish and characterize the α3 * and α5 * nAChR-mediated Ca2+ influx, we measured the [Ca2+]i elevation induced by nonmembrane-permeating acetylcholine when muscarinic receptors, α7nAChR and Ca2+ channels were blocked. Under this condition, the [Ca2+]i elevation was significantly inhibited with a 48-h treatment of dibutyryl cAMP, which was accompanied by the downregulation of α3 and β4 mRNA. These findings suggest that α3 * and α5 * nAChR-mediated Ca2+ influx is possibly regulated by cAMP at the transcriptional level.
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Affiliation(s)
- Tamayo Takahashi
- Department of Molecular and Pharmacological Neuroscience, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
- Department of Dental Anesthesiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Takayuki Yoshida
- Department of Neurophysiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Kana Harada
- Department of Molecular and Pharmacological Neuroscience, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Tatsuhiko Miyagi
- Department of Molecular and Pharmacological Neuroscience, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Kouichi Hashimoto
- Department of Neurophysiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Izumi Hide
- Department of Molecular and Pharmacological Neuroscience, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Shigeru Tanaka
- Department of Molecular and Pharmacological Neuroscience, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Masahiro Irifune
- Department of Dental Anesthesiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Norio Sakai
- Department of Molecular and Pharmacological Neuroscience, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
- * E-mail:
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21
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Lee AM, Picciotto MR. Effects of nicotine on DARPP-32 and CaMKII signaling relevant to addiction. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2020; 90:89-115. [PMID: 33706940 PMCID: PMC8008986 DOI: 10.1016/bs.apha.2020.09.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/29/2023]
Abstract
Paul Greengard brought to neuroscience the idea of, and evidence for, the role of second messenger systems in neuronal signaling. The fundamental nature of his contributions is evident in the far reach of his work, relevant to various subfields and topics in neuroscience. In this review, we discuss some of Greengard's work from the perspective of nicotinic acetylcholine receptors and their relevance to nicotine addiction. Specifically, we review the roles of dopamine- and cAMP-regulated phospho-protein of 32kDa (DARPP-32) and Ca2+/calmodulin-dependent kinase II (CaMKII) in nicotine-dependent behaviors. For each protein, we discuss the historical context of their discovery and initial characterization, focusing on the extensive biochemical and immunohistochemical work conducted by Greengard and colleagues. We then briefly summarize contemporary understanding of each protein in key intracellular signaling cascades and evidence for the role of each protein with respect to systems and behaviors relevant to nicotine addiction.
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Affiliation(s)
- Angela M Lee
- Department of Psychiatry, Yale University, New Haven, CT, United States; Yale Interdepartmental Neuroscience Program, New Haven, CT, United States
| | - Marina R Picciotto
- Department of Psychiatry, Yale University, New Haven, CT, United States; Yale Interdepartmental Neuroscience Program, New Haven, CT, United States.
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22
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Miller DR, Khoshbouei H, Garai S, Cantwell LN, Stokes C, Thakur G, Papke RL. Allosterically Potentiated α7 Nicotinic Acetylcholine Receptors: Reduced Calcium Permeability and Current-Independent Control of Intracellular Calcium. Mol Pharmacol 2020; 98:695-709. [PMID: 33020143 DOI: 10.1124/molpharm.120.000012] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Accepted: 09/10/2020] [Indexed: 11/22/2022] Open
Abstract
The currents of α7 nicotinic acetylcholine receptors activated by acetylcholine (ACh) are brief. The channel has high permeability to calcium relative to monovalent cations and shows inward rectification. It has been previously noted that in the presence of positive allosteric modulators (PAMs), currents through the channels of α7 receptors differ from normal α7 currents both in sensitivity to specific channel blockers and their current-voltage (I-V) relationships, no longer showing inward rectification. Linear I-V functions are often associated with channels lacking calcium permeability, so we measured the I-V functions of α7 receptors activated by ACh when PAMs were bound to the allosteric binding site in the transmembrane domain. Currents were recorded in chloride-free Ringer's solution with low or high concentrations of extracellular calcium to determine the magnitude of the reversal potential shift in the two conditions as well as the I-V relationships. ACh-evoked currents potentiated by the allosteric agonist-PAMs (ago-PAMs) (3aR,4S,9bS)-4-(4-bromophenyl)-3a,4,5,9b-tetrahydro-3H-cyclopenta[c]quinoline-8-sulfonamide (GAT107) and 3-(3,4-difluorophenyl)-N-(1-(6-(4-(pyridin-2-yl)piperazin-1-yl)pyrazin-2-yl)ethyl)propenamide (B-973B) showed reduced inward rectification and calcium-dependent reversal potential shifts decreased by 80%, and 50%, respectively, compared with currents activated by ACh alone, indicative of reduced calcium permeability. Currents potentiated by 3a,4,5,9b-tetrahydro-4-(1-naphthalenyl)-3H-cyclopentan[c]quinoline-8-sulfonamide were also linear and showed no calcium-dependent reversal potential shifts. The ago-PAMs GAT-107 and B-973B stimulated increases in intracellular calcium in stably transfected HEK293 cells. However, these calcium signals were delayed relative to channel activation produced by these agents and were insensitive to the channel blocker mecamylamine. Our results indicate that, although allosterically activated α7 nicotinic ACh receptor may affect intracellular calcium levels, such effects are not likely due to large channel-dependent calcium influx. SIGNIFICANCE STATEMENT: Positive allosteric modulators (PAMs) of α7 nicotinic acetylcholine receptor can increase channel activation by two or more orders of magnitude, raising the concern that, due to the relatively high calcium permeability of α7 receptors activated by acetylcholine alone, such efficacious PAMs may have cytotoxic side effects. We show that PAMs alter the ion conduction pathway and, in general, reduce the calcium permeability of the channels. This supports the hypothesis that α7 effects on intracellular calcium may be independent of channel-mediated calcium influx.
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Affiliation(s)
- Douglas R Miller
- Departments of Neuroscience (D.R.M., H.K.) and Pharmacology and Therapeutics (C.S., R.L.P.), University of Florida, Gainesville, Florida; and Department of Pharmaceutical Sciences, School of Pharmacy, Bouvé College of Health Sciences, Northeastern University, Boston, Massachusetts (S.G., L.N.C., G.T.)
| | - Habibeh Khoshbouei
- Departments of Neuroscience (D.R.M., H.K.) and Pharmacology and Therapeutics (C.S., R.L.P.), University of Florida, Gainesville, Florida; and Department of Pharmaceutical Sciences, School of Pharmacy, Bouvé College of Health Sciences, Northeastern University, Boston, Massachusetts (S.G., L.N.C., G.T.)
| | - Sumanta Garai
- Departments of Neuroscience (D.R.M., H.K.) and Pharmacology and Therapeutics (C.S., R.L.P.), University of Florida, Gainesville, Florida; and Department of Pharmaceutical Sciences, School of Pharmacy, Bouvé College of Health Sciences, Northeastern University, Boston, Massachusetts (S.G., L.N.C., G.T.)
| | - Lucas N Cantwell
- Departments of Neuroscience (D.R.M., H.K.) and Pharmacology and Therapeutics (C.S., R.L.P.), University of Florida, Gainesville, Florida; and Department of Pharmaceutical Sciences, School of Pharmacy, Bouvé College of Health Sciences, Northeastern University, Boston, Massachusetts (S.G., L.N.C., G.T.)
| | - Clare Stokes
- Departments of Neuroscience (D.R.M., H.K.) and Pharmacology and Therapeutics (C.S., R.L.P.), University of Florida, Gainesville, Florida; and Department of Pharmaceutical Sciences, School of Pharmacy, Bouvé College of Health Sciences, Northeastern University, Boston, Massachusetts (S.G., L.N.C., G.T.)
| | - Ganesh Thakur
- Departments of Neuroscience (D.R.M., H.K.) and Pharmacology and Therapeutics (C.S., R.L.P.), University of Florida, Gainesville, Florida; and Department of Pharmaceutical Sciences, School of Pharmacy, Bouvé College of Health Sciences, Northeastern University, Boston, Massachusetts (S.G., L.N.C., G.T.)
| | - Roger L Papke
- Departments of Neuroscience (D.R.M., H.K.) and Pharmacology and Therapeutics (C.S., R.L.P.), University of Florida, Gainesville, Florida; and Department of Pharmaceutical Sciences, School of Pharmacy, Bouvé College of Health Sciences, Northeastern University, Boston, Massachusetts (S.G., L.N.C., G.T.)
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Papke RL, Lindstrom JM. Nicotinic acetylcholine receptors: Conventional and unconventional ligands and signaling. Neuropharmacology 2020; 168:108021. [PMID: 32146229 PMCID: PMC7610230 DOI: 10.1016/j.neuropharm.2020.108021] [Citation(s) in RCA: 65] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Revised: 02/05/2020] [Accepted: 02/25/2020] [Indexed: 12/28/2022]
Abstract
Postsynaptic nAChRs in the peripheral nervous system are critical for neuromuscular and autonomic neurotransmission. Pre- and peri-synaptic nAChRs in the brain modulate neurotransmission and are responsible for the addictive effects of nicotine. Subtypes of nAChRs in lymphocytes and non-synaptic locations may modulate inflammation and other cellular functions. All AChRs that function as ligand-gated ion channels are formed from five homologous subunits organized to form a central cation channel whose opening is regulated by ACh bound at extracellular subunit interfaces. nAChR subtype subunit composition can range from α7 homomers to α4β2α6β2β3 heteromers. Subtypes differ in affinities for ACh and other agonists like nicotine and in efficiencies with which their channels are opened and desensitized. Subtypes also differ in affinities for antagonists and for positive and negative allosteric modulators. Some agonists are "silent" with respect to channel opening, and AChRs may be able to signal metabotropic pathways by releasing G-proteins independent of channel opening. Electrophysiological studies that can resolve single-channel openings and molecular genetic approaches have allowed characterization of the structures of ligand binding sites, the cation channel, and the linkages between them, as well as the organization of AChR subunits and their contributions to function. Crystallography and cryo-electron-microscopy are providing increasing insights into the structures and functions of AChRs. However, much remains to be learned about both AChR structure and function, the in vivo functional roles of some AChR subtypes, and the development of better pharmacological tools directed at AChRs to treat addiction, pain, inflammation, and other medically important issues. This article is part of the special issue on 'Contemporary Advances in Nicotine Neuropharmacology'.
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Affiliation(s)
- Roger L Papke
- Department of Pharmacology and Therapeutics, University of Florida, P.O. Box 100267, Gainesville, FL, 32610-0267, USA.
| | - Jon M Lindstrom
- Department of Neuroscience, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
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Mangan D, McNabola N, Clark EH, Bermudez I, Wonnacott S, Southern JM. Ethyl-for-methyl substitution enhances the subtype specificity of mecamylamine analogues. Org Biomol Chem 2019; 17:9892-9905. [PMID: 31713564 DOI: 10.1039/c9ob01993f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The synthesis of novel mecamylamine analogues is described in which one, two or three of the methyl groups of mecamylamine have been systematically replaced with ethyl groups. Assessment of the compounds highlights that simple ethyl for methyl changes changes to the parent structure can dramatically enhance activity and selectivity towards either the α4β2 (at the expense of α3β4) or the α3β4 (at the expense of α4β2) nicotinic acetylcholine receptor sub-type as compared to the parent compound.
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Affiliation(s)
- David Mangan
- Trinity Biomedical Sciences Institute, School of Chemistry, The University of Dublin, Trinity College, Dublin 2, Ireland.
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25
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Hepnarova V, Muckova L, Ring A, Pejchal J, Herman D, Misik J, Hrabinova M, Jun D, Soukup O. Pharmacological and toxicological in vitro and in vivo effect of higher doses of oxime reactivators. Toxicol Appl Pharmacol 2019; 383:114776. [DOI: 10.1016/j.taap.2019.114776] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2019] [Revised: 09/18/2019] [Accepted: 10/04/2019] [Indexed: 12/26/2022]
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Larsen HM, Hansen SK, Mikkelsen JD, Hyttel P, Stummann TC. Alpha7 nicotinic acetylcholine receptors and neural network synaptic transmission in human induced pluripotent stem cell-derived neurons. Stem Cell Res 2019; 41:101642. [PMID: 31707211 DOI: 10.1016/j.scr.2019.101642] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 10/09/2019] [Accepted: 10/28/2019] [Indexed: 01/09/2023] Open
Abstract
The α7 nicotinic acetylcholine receptor has been extensively researched as a target for treatment of cognitive impairment in Alzheimer's disease and schizophrenia. Investigation of the α7 receptor is commonly performed in animals but it is critical to increase the biologically relevance of the model systems to fully capture the physiological role of the α7 receptor in humans. For example most humans, in contrast to animals, express the hybrid gene CHRFAM7A, the product of which modulates α7 receptor activity. In the present study, we used human induced pluripotent stem cell (hiPSC) derived neurons to establish a humanized α7 model. We established a cryobank of neural stem cells (NSCs) that could reproducibly be matured into neurons expressing neuronal markers and CHRNA7 and CHRFAM7A. The neurons responded to NMDA, GABA, and acetylcholine and exhibited synchronized spontaneous calcium oscillations. Gene expression studies and application of a range of α7 positive allosteric modulators (PNU-120595, TQS, JNJ-39393406 and AF58801) together with the α7 agonist PNU-282987 during measurement of intracellular calcium levels demonstrated the presence of functional α7 receptors in matured hiPSC-derived neuronal cultures. Pharmacological α7 activation also resulted in intracellular signaling as measured by ERK 1/2 phosphorylation and c-Fos protein expression. Moreover, PNU-120596 increased the frequency of the spontaneous calcium oscillations demonstrating implication of α7 receptors in human synaptic networks activity. Overall, we show that hiPSC derived neurons are an advanced in vitro model for studying human α7 receptor pharmacology and the involvement of this receptor in cellular processes as intracellular signaling and synaptic transmission.
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Affiliation(s)
- Hjalte M Larsen
- Stem Cells and Embryology Group, Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Susanne K Hansen
- Stem Cells and Embryology Group, Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Jens D Mikkelsen
- Neurobiology Research Unit, University Hospital Copenhagen, Rigshospitalet, Denmark
| | - Poul Hyttel
- Stem Cells and Embryology Group, Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
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Hirano T, Minagawa S, Furusawa Y, Yunoki T, Ikenaka Y, Yokoyama T, Hoshi N, Tabuchi Y. Growth and neurite stimulating effects of the neonicotinoid pesticide clothianidin on human neuroblastoma SH-SY5Y cells. Toxicol Appl Pharmacol 2019; 383:114777. [PMID: 31626844 DOI: 10.1016/j.taap.2019.114777] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2019] [Revised: 10/03/2019] [Accepted: 10/05/2019] [Indexed: 10/25/2022]
Abstract
Neonicotinoids are one of most widely used pesticides targeting nicotinic acetylcholine receptors (nAChRs) of insects. Recent epidemiological evidence revealed increasing amounts of neonicotinoids detected in human samples, raising the critical question of whether neonicotinoids affect human health. We investigated the effects of a neonicotinoid pesticide clothianidin (CTD) on human neuroblastoma SH-SY5Y cells as in vitro models of human neuronal cells. Cellular and functional effects of micromolar doses of CTD were evaluated by changes in cell growth, intracellular signaling activities and gene expression profiles. We examined further the effects of CTD on neuronal differentiation by measuring neurite outgrowth. Exposure to CTD (1-100 μM) significantly increased the number of cells within 24 h of culture. The nAChRs antagonists, mecamylamine and SR16584, inhibited this effect, suggesting human α3β4 nAChRs could be targets of neonicotinoids. We observed a transient intracellular calcium influx and increased phosphorylation of extracellular signal-regulated kinase 1/2 shortly after exposure to CTD. Transcriptome analysis revealed that CTD down-regulated genes involved in neuronal function (e.g., formation of filopodia and calcium ion influx) and morphology (e.g., axon guidance signaling and cytoskeleton signaling); these changes were reflected by a finding of increased neurite length during neuronal differentiation. These findings provide novel insight into the potential risks of neonicotinoids to the human nervous system.
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Affiliation(s)
- Tetsushi Hirano
- Life Science Research Center, University of Toyama, Toyama, Japan.
| | - Satsuki Minagawa
- Life Science Research Center, University of Toyama, Toyama, Japan
| | - Yukihiro Furusawa
- Department of Liberal Arts and Sciences, Toyama Prefectural University, Toyama, Japan
| | - Tatsuya Yunoki
- Department of Ophthalmology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan
| | - Yoshinori Ikenaka
- Laboratory of Toxicology, Department of Environmental Veterinary Sciences, Faculty of Veterinary Medicine, Hokkaido University, Sapporo, Hokkaido, Japan; Water Research Group, Unit for Environmental Sciences and Management, North-West University, Potchefstroom, South Africa
| | - Toshifumi Yokoyama
- Department of Animal Science, Graduate School of Agricultural Science, Kobe University, Kobe, Hyogo, Japan
| | - Nobuhiko Hoshi
- Department of Animal Science, Graduate School of Agricultural Science, Kobe University, Kobe, Hyogo, Japan
| | - Yoshiaki Tabuchi
- Life Science Research Center, University of Toyama, Toyama, Japan
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28
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Xu S, Yang B, Tao T, Zhang J, Liu Y, Hu J, Fan Y, Zhang G. Activation of α7-nAChRs protects SH-SY5Y cells from 1-methyl-4-phenylpyridinium-induced apoptotic cell death via ERK/p53 signaling pathway. J Cell Physiol 2019; 234:18480-18491. [PMID: 30912145 DOI: 10.1002/jcp.28484] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2018] [Revised: 02/18/2019] [Accepted: 02/20/2019] [Indexed: 12/22/2022]
Abstract
Epidemiologic studies have shown a reduced risk of developing Parkinson's disease (PD) among cigarette smokers. Nicotine, as a key component in tobacco products, is thought as a possible candidate for action of smoking in neuroprotection. α7 nicotinic acetylcholine receptors (α7-nAChRs) is one of the most abundant nAChRs in the mammalian brain. Although nicotine is thought to exert this protective action by acting on nicotinic receptors, including the α7-nAChRs; the mechanisms underlying how α7-nAChRs protect against dopaminergic neuron loss are highly complex. Using nicotine and a selective α7-nAChR agonist PNU-282987, we first confirmed that their addition to SH-SY5Y cells challenged with 1-methyl-4-phenylpyridinium (MPP+ ) could afford neuroprotection and result in a reduction in apoptotic cell death. Then, we found that the pretreatment with nicotine and PNU-282987 showed the neuroprotective antiapoptotic effects via activating the α7-nAChRs/MAPK/p53 axis. Furthermore, we used RNA interference to silence the expression of α7-nAChRs in SH-SY5Y cells and found that suppressing α7-nAChR expression diminished the antiapoptotic effects of nicotine and PNU-282987, not the toxic effects of MPP+ . Moreover, α7-nAChR knockdown could only decrease the inhibitory effects of nicotine and PNU-282987 on the phosphorylated extracellular signal-regulated kinase (ERK), not c-Jun amino-terminal kinase and p38. Therefore, our findings indicate the important roles of ERK/MAPK signaling in the neuroprotective effects of α7-nAChRs and suggest that α7-nAChR agonists may be validated as novel treatments for PD.
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Affiliation(s)
- Shi Xu
- Jiangsu Key Laboratory of Neurodegeneration, Department of Pharmacology, Neuroprotective Drug Discovery Center, Nanjing Medical University, Nanjing, Jiangsu, China.,Jiangsu Key Laboratory of Oral Diseases, Department of Endodontics and Operative Dentistry, Affiliated Hospital of Stomatology, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Beibei Yang
- Jiangsu Key Laboratory of Neurodegeneration, Department of Pharmacology, Neuroprotective Drug Discovery Center, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Tingting Tao
- Jiangsu Key Laboratory of Neurodegeneration, Department of Pharmacology, Neuroprotective Drug Discovery Center, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Ji Zhang
- Department of Pharmacy, Division of Clinical Pharmacy, The First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu, China
| | - Yun Liu
- Department of Infectious Diseases, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Jun Hu
- Department of Orthopedics, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Yi Fan
- Jiangsu Key Laboratory of Neurodegeneration, Department of Pharmacology, Neuroprotective Drug Discovery Center, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Guangdong Zhang
- Jiangsu Key Laboratory of Oral Diseases, Department of Endodontics and Operative Dentistry, Affiliated Hospital of Stomatology, Nanjing Medical University, Nanjing, Jiangsu, China
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Kulbatskii DS, Bychkov ML, Lyukmanova EN. Human Nicotinic Acetylcholine Receptors: Part I—Structure, Function, and Role in Neuromuscular Transmission and CNS Functioning. RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY 2019. [DOI: 10.1134/s1068162018060043] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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30
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Majdi A, Kamari F, Sadigh-Eteghad S, Gjedde A. Molecular Insights Into Memory-Enhancing Metabolites of Nicotine in Brain: A Systematic Review. Front Neurosci 2019; 12:1002. [PMID: 30697142 PMCID: PMC6341027 DOI: 10.3389/fnins.2018.01002] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Accepted: 12/12/2018] [Indexed: 01/25/2023] Open
Abstract
Background: The alleged procognitive effects of nicotine and its metabolites in brain are controversial. Objective: Here, we review the pharmacologically active metabolites of nicotine in brain and their effects on neuronal mechanisms involving two main cognitive domains, i.e., learning and memory. Methods: We searched Embase, Medline via PubMed, Scopus, and Web of Science databases for entries no later than May 2018, and restricted the search to articles about nicotine metabolites and cognitive behavior or cognitive mechanisms. Results: The initial search yielded 425 articles, of which 17 were eligible for inclusion after application of exclusion criteria. Of these, 13 were experimental, two were clinical, and two were conference papers. Conclusions: The results revealed three pharmacologically active biotransformations of nicotine in the brain, including cotinine, norcotinine, and nornicotine, among which cotinine and nornicotine both had a procognitive impact without adverse effects. The observed effect was significant only for cotinine.
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Affiliation(s)
- Alireza Majdi
- Neurosciences Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Farzin Kamari
- Neurosciences Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Saeed Sadigh-Eteghad
- Neurosciences Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Albert Gjedde
- Neurosciences Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
- Department of Clinical Research, University of Southern Denmark, Odense, Denmark
- Department of Neuroscience, University of Copenhagen, Copenhagen, Denmark
- Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
- Department of Radiology and Radiological Science, Johns Hopkins University, Baltimore, MD, United States
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31
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Chung BYT, Bailey CDC. Similar nicotinic excitability responses across the developing hippocampal formation are regulated by small-conductance calcium-activated potassium channels. J Neurophysiol 2018; 119:1707-1722. [PMID: 29384449 DOI: 10.1152/jn.00426.2017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The hippocampal formation forms a cognitive circuit that is critical for learning and memory. Cholinergic input to nicotinic acetylcholine receptors plays an important role in the normal development of principal neurons within the hippocampal formation. However, the ability of nicotinic receptors to stimulate principal neurons across all regions of the developing hippocampal formation has not been determined. We show in this study that heteromeric nicotinic receptors mediate direct inward current and depolarization responses in principal neurons across the hippocampal formation of the young postnatal mouse. These responses were found in principal neurons of the CA1, CA3, dentate gyrus, subiculum, and entorhinal cortex layer VI, and they varied in magnitude across regions with the greatest responses occurring in the subiculum and entorhinal cortex. Despite this regional variation in the magnitude of passive responses, heteromeric nicotinic receptor stimulation increased the excitability of active principal neurons by a similar amount in all regions. Pharmacological experiments found this similar excitability response to be regulated by small-conductance calcium-activated potassium (SK) channels, which exhibited regional differences in their influence on neuron activity that offset the observed regional differences in passive nicotinic responses. These findings demonstrate that SK channels play a role to coordinate the magnitude of heteromeric nicotinic excitability responses across the hippocampal formation at a time when nicotinic signaling drives the development of this cognitive brain region. This coordinated input may contribute to the normal development, synchrony, and maturation of the hippocampal formation learning and memory network. NEW & NOTEWORTHY This study demonstrates that small-conductance calcium-activated potassium channels regulate similar-magnitude excitability responses to heteromeric nicotinic acetylcholine receptor stimulation in active principal neurons across multiple regions of the developing mouse hippocampal formation. Given the importance of nicotinic neurotransmission for the development of principal neurons within the hippocampal formation, this coordinated excitability response is positioned to influence the normal development, synchrony, and maturation of the hippocampal formation learning and memory network.
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Affiliation(s)
- Beryl Y T Chung
- Department of Biomedical Sciences, University of Guelph , Guelph, Ontario , Canada
| | - Craig D C Bailey
- Department of Biomedical Sciences, University of Guelph , Guelph, Ontario , Canada
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32
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Elnagar MR, Walls AB, Helal GK, Hamada FM, Thomsen MS, Jensen AA. Functional characterization of α7 nicotinic acetylcholine and NMDA receptor signaling in SH-SY5Y neuroblastoma cells in an ERK phosphorylation assay. Eur J Pharmacol 2018; 826:106-113. [DOI: 10.1016/j.ejphar.2018.02.047] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Revised: 02/20/2018] [Accepted: 02/28/2018] [Indexed: 12/23/2022]
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33
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Kabbani N, Nichols RA. Beyond the Channel: Metabotropic Signaling by Nicotinic Receptors. Trends Pharmacol Sci 2018; 39:354-366. [PMID: 29428175 DOI: 10.1016/j.tips.2018.01.002] [Citation(s) in RCA: 115] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2017] [Revised: 01/05/2018] [Accepted: 01/08/2018] [Indexed: 01/01/2023]
Abstract
The α7 nicotinic acetylcholine receptor (nAChR) is a ligand-gated ion channel (LGIC) that plays an important role in cellular calcium signaling and contributes to several neurological diseases. Agonist binding to the α7 nAChR induces fast channel activation followed by inactivation and prolonged desensitization while triggering long-lasting calcium signaling. These activities foster neurotransmitter release, synaptic plasticity, and somatodendritic regulation in the brain. We discuss here the ability of α7 nAChRs to operate in ionotropic (α7i) and metabotropic (α7m) modes, leading to calcium-induced calcium release (CICR) and G protein-associated inositol trisphosphate (IP3)-induced calcium release (IICR), respectively. Metabotropic activity extends the spatial and temporal aspects of calcium signaling by the α7 channel beyond its ionotropic limits, persisting into the desensitized state. Delineation of the ionotropic and metabotropic properties of the α7 nAChR will provide definitive indicators of moment-to-moment receptor functional status that will, in turn, spearhead new drug development.
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Affiliation(s)
- Nadine Kabbani
- School of Systems Biology, George Mason University, Manassas, VA 20110, USA.
| | - Robert A Nichols
- Department of Cell and Molecular Biology, University of Hawai'i at Manoa, Honolulu, HI 96813, USA
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Gong Q, Wen X, Li H, He J, Wang Y, Wu H, Wang H, Wang X. Up-regulation of Cav3.1 expression in SH-SY5Y cells induced by lidocaine hydrochloride. ARTIFICIAL CELLS NANOMEDICINE AND BIOTECHNOLOGY 2018; 46:372-379. [PMID: 29327607 DOI: 10.1080/21691401.2018.1425697] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- Qin Gong
- Department of Pain Management, The First Affiliated Hospital of Jinan University, Guangzhou, Guangdong Province, China
- Department of Anesthesiology, Foshan Hospital of Traditional Chinese Medicine, Foshan, Guangdong Province, China
| | - Xianjie Wen
- Department of Anesthesiology, The First People’s Hospital of Foshan & Foshan Hospital of Sun Yat-sen University, Foshan, Guangdong Province, China
| | - Heng Li
- Department of Anesthesiology, The Sixth Affiliated Hospital of Guangzhou Medical University, Qinyuan, Guangdong Province, China
| | - Jian He
- Department of Anesthesiology, The First People’s Hospital of Foshan & Foshan Hospital of Sun Yat-sen University, Foshan, Guangdong Province, China
| | - Yunhua Wang
- Department of Anesthesiology, The First People’s Hospital of Foshan & Foshan Hospital of Sun Yat-sen University, Foshan, Guangdong Province, China
| | - Huiping Wu
- Department of Anesthesiology, The First People’s Hospital of Foshan & Foshan Hospital of Sun Yat-sen University, Foshan, Guangdong Province, China
| | - Hanbing Wang
- Department of Anesthesiology, The First People’s Hospital of Foshan & Foshan Hospital of Sun Yat-sen University, Foshan, Guangdong Province, China
| | - Xiaoping Wang
- Department of Pain Management, The First Affiliated Hospital of Jinan University, Guangzhou, Guangdong Province, China
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35
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Bouzat C, Lasala M, Nielsen BE, Corradi J, Esandi MDC. Molecular function of α7 nicotinic receptors as drug targets. J Physiol 2017; 596:1847-1861. [PMID: 29131336 DOI: 10.1113/jp275101] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Accepted: 11/02/2017] [Indexed: 12/20/2022] Open
Abstract
Nicotinic acetylcholine receptors (nAChRs) are pentameric ligand-gated ion channels involved in many physiological and pathological processes. In vertebrates, there are seventeen different nAChR subunits that combine to yield a variety of receptors with different pharmacology, function, and localization. The homomeric α7 receptor is one of the most abundant nAChRs in the nervous system and it is also present in non-neuronal cells. It plays important roles in cognition, memory, pain, neuroprotection, and inflammation. Its diverse physiological actions and associated disorders have made of α7 an attractive novel target for drug modulation. Potentiation of the α7 receptor has emerged as a novel therapeutic strategy for several neurological diseases, such as Alzheimer's and Parkinson's diseases, and inflammatory disorders. In contrast, increased α7 activity has been associated with cancer cell proliferation. The presence of different drug target sites offers a great potential for α7 modulation in different pathological contexts. In particular, compounds that target allosteric sites offer significant advantages over orthosteric agonists due to higher selectivity and a broader spectrum of degrees and mechanisms of modulation. Heterologous expression of α7, together with chaperone proteins, combined with patch clamp recordings have provided important advances in our knowledge of the molecular basis of α7 responses and their potential modulation for pathological processes. This review gives a synthetic view of α7 and its molecular function, focusing on how its unique activation and desensitization features can be modified by pharmacological agents. This fundamental information offers insights into therapeutic strategies.
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Affiliation(s)
- Cecilia Bouzat
- Instituto de Investigaciones Bioquímicas de Bahía Blanca, Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur, CONICET/UNS, 8000, Bahía Blanca, Argentina
| | - Matías Lasala
- Instituto de Investigaciones Bioquímicas de Bahía Blanca, Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur, CONICET/UNS, 8000, Bahía Blanca, Argentina
| | - Beatriz Elizabeth Nielsen
- Instituto de Investigaciones Bioquímicas de Bahía Blanca, Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur, CONICET/UNS, 8000, Bahía Blanca, Argentina
| | - Jeremías Corradi
- Instituto de Investigaciones Bioquímicas de Bahía Blanca, Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur, CONICET/UNS, 8000, Bahía Blanca, Argentina
| | - María Del Carmen Esandi
- Instituto de Investigaciones Bioquímicas de Bahía Blanca, Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur, CONICET/UNS, 8000, Bahía Blanca, Argentina
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36
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Lazarevic V, Fieńko S, Andres-Alonso M, Anni D, Ivanova D, Montenegro-Venegas C, Gundelfinger ED, Cousin MA, Fejtova A. Physiological Concentrations of Amyloid Beta Regulate Recycling of Synaptic Vesicles via Alpha7 Acetylcholine Receptor and CDK5/Calcineurin Signaling. Front Mol Neurosci 2017; 10:221. [PMID: 28785201 PMCID: PMC5520466 DOI: 10.3389/fnmol.2017.00221] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Accepted: 06/26/2017] [Indexed: 01/09/2023] Open
Abstract
Despite the central role of amyloid β (Aβ) peptide in the etiopathogenesis of Alzheimer’s disease (AD), its physiological function in healthy brain is still debated. It is well established that elevated levels of Aβ induce synaptic depression and dismantling, connected with neurotoxicity and neuronal loss. Growing evidence suggests a positive regulatory effect of Aβ on synaptic function and cognition; however the exact cellular and molecular correlates are still unclear. In this work, we tested the effect of physiological concentrations of Aβ species of endogenous origin on neurotransmitter release in rat cortical and hippocampal neurons grown in dissociated cultures. Modulation of production and degradation of the endogenous Aβ species as well as applications of the synthetic rodent Aβ40 and Aβ42 affected efficacy of neurotransmitter release from individual presynapses. Low picomolar Aβ40 and Aβ42 increased, while Aβ depletion or application of low micromolar concentration decreased synaptic vesicle recycling, showing a hormetic effect of Aβ on neurotransmitter release. These Aβ-mediated modulations required functional alpha7 acetylcholine receptors as well as extracellular and intracellular calcium, involved regulation of CDK5 and calcineurin signaling and increased recycling of synaptic vesicles. These data indicate that Aβ regulates neurotransmitter release from presynapse and suggest that failure of the normal physiological function of Aβ in the fine-tuning of SV cycling could disrupt synaptic function and homeostasis, which would, eventually, lead to cognitive decline and neurodegeneration.
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Affiliation(s)
- Vesna Lazarevic
- RG Presynaptic Plasticity, Leibniz Institute for NeurobiologyMagdeburg, Germany.,Department of Neurochemistry and Molecular Biology, Leibniz Institute for NeurobiologyMagdeburg, Germany.,German Center for Neurodegenerative Diseases (DZNE)Magdeburg, Germany
| | - Sandra Fieńko
- RG Presynaptic Plasticity, Leibniz Institute for NeurobiologyMagdeburg, Germany
| | - Maria Andres-Alonso
- RG Presynaptic Plasticity, Leibniz Institute for NeurobiologyMagdeburg, Germany
| | - Daniela Anni
- Molecular Psychiatry, Department of Psychiatry and Psychotherapy, University Hospital, University of Erlangen-NurembergErlangen, Germany
| | - Daniela Ivanova
- RG Presynaptic Plasticity, Leibniz Institute for NeurobiologyMagdeburg, Germany
| | | | - Eckart D Gundelfinger
- Department of Neurochemistry and Molecular Biology, Leibniz Institute for NeurobiologyMagdeburg, Germany.,German Center for Neurodegenerative Diseases (DZNE)Magdeburg, Germany.,Center for Behavioral Brain Sciences, Otto von Guericke UniversityMagdeburg, Germany.,Medical Faculty, Otto von Guericke UniversityMagdeburg, Germany
| | - Michael A Cousin
- Centre for Integrative Physiology, University of EdinburghEdinburgh, United Kingdom
| | - Anna Fejtova
- RG Presynaptic Plasticity, Leibniz Institute for NeurobiologyMagdeburg, Germany.,Department of Neurochemistry and Molecular Biology, Leibniz Institute for NeurobiologyMagdeburg, Germany.,Molecular Psychiatry, Department of Psychiatry and Psychotherapy, University Hospital, University of Erlangen-NurembergErlangen, Germany.,Center for Behavioral Brain Sciences, Otto von Guericke UniversityMagdeburg, Germany
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37
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Cárdenas AM, Fernández-Olivares P, Díaz-Franulic I, González-Jamett AM, Shimahara T, Segura-Aguilar J, Caviedes R, Caviedes P. Knockdown of Myo-Inositol Transporter SMIT1 Normalizes Cholinergic and Glutamatergic Function in an Immortalized Cell Line Established from the Cerebral Cortex of a Trisomy 16 Fetal Mouse, an Animal Model of Human Trisomy 21 (Down Syndrome). Neurotox Res 2017; 32:614-623. [PMID: 28695546 DOI: 10.1007/s12640-017-9775-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Revised: 06/21/2017] [Accepted: 06/28/2017] [Indexed: 12/31/2022]
Abstract
The Na+/myo-inositol cotransporter (SMIT1) is overexpressed in human Down syndrome (DS) and in trisomy 16 fetal mice (Ts16), an animal model of the human condition. SMIT1 overexpression determines increased levels of intracellular myo-inositol, a precursor of phophoinositide synthesis. SMIT1 is overexpressed in CTb cells, an immortalized cell line established from the cerebral cortex of a Ts16 mouse fetus. CTb cells exhibit impaired cytosolic Ca2+ signals in response to glutamatergic and cholinergic stimuli (increased amplitude and delayed time-dependent kinetics in the decay post-stimulation), compared to our CNh cell line, derived from the cerebral cortex of a euploid animal. Considering the role of myo-inositol in intracellular signaling, we normalized SMIT1 expression in CTb cells using specific mRNA antisenses. Forty-eight hours post-transfection, SMIT1 levels in CTb cells reached values comparable to those of CNh cells. At this time, decay kinetics of Ca2+ signals induced by either glutamate, nicotine, or muscarine were accelerated in transfected CTb cells, to values similar to those of CNh cells. The amplitude of glutamate-induced cytosolic Ca2+ signals in CTb cells was also normalized. The results suggest that SMIT1 overexpression contributes to abnormal cholinergic and glutamatergic Ca2+ signals in the trisomic condition, and knockdown of DS-related genes in our Ts16-derived cell line could constitute a relevant tool to study DS-related neuronal dysfunction.
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Affiliation(s)
- Ana María Cárdenas
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Paola Fernández-Olivares
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
- Program of Molecular and Clinical Pharmacology, ICBM, Faculty of Medicine, University of Chile, Clasificador 7, Independencia, 1027, Santiago, Chile
| | - Ignacio Díaz-Franulic
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
- Center for Bioinformatics and Integrative Biology, Universidad Andrés Bello, Santiago, Chile
- Fundación Fraunhofer Chile, Las Condes, Chile
| | - Arlek M González-Jamett
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | | | - Juan Segura-Aguilar
- Program of Molecular and Clinical Pharmacology, ICBM, Faculty of Medicine, University of Chile, Clasificador 7, Independencia, 1027, Santiago, Chile
| | - Raúl Caviedes
- Program of Molecular and Clinical Pharmacology, ICBM, Faculty of Medicine, University of Chile, Clasificador 7, Independencia, 1027, Santiago, Chile
| | - Pablo Caviedes
- Program of Molecular and Clinical Pharmacology, ICBM, Faculty of Medicine, University of Chile, Clasificador 7, Independencia, 1027, Santiago, Chile.
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Mangan D, McNabola N, Clark EH, Bermudez I, Wonnacott S, Southern JM. A new synthesis and preliminary evaluation of some analogues of mecamylamine - a compound with anti-addiction properties. Org Biomol Chem 2016; 14:10787-10798. [PMID: 27812593 DOI: 10.1039/c6ob01974a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A new synthesis of mecamylamine - a known anti-hypertensive drug with anti-addictive properties is described. The new route allowed access to two novel analogues whose activity at two nicotinic acetylcholine receptor subtypes was assessed.
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Affiliation(s)
- David Mangan
- Trinity Biomedical Sciences Institute, School of Chemistry, The University of Dublin, Trinity College, Dublin 2, Ireland.
| | - Neasa McNabola
- Trinity Biomedical Sciences Institute, School of Chemistry, The University of Dublin, Trinity College, Dublin 2, Ireland.
| | - Emily H Clark
- Department of Biology & Biochemistry, University of Bath, Bath BA2 7AY, UK
| | - Isabel Bermudez
- School of Life Sciences, Oxford Brookes University, Oxford OX3 0BP, UK
| | - Susan Wonnacott
- Department of Biology & Biochemistry, University of Bath, Bath BA2 7AY, UK
| | - J Mike Southern
- Trinity Biomedical Sciences Institute, School of Chemistry, The University of Dublin, Trinity College, Dublin 2, Ireland.
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Ghasemi M, Hadipour-Niktarash A. Pathologic role of neuronal nicotinic acetylcholine receptors in epileptic disorders: implication for pharmacological interventions. Rev Neurosci 2016; 26:199-223. [PMID: 25565544 DOI: 10.1515/revneuro-2014-0044] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2014] [Accepted: 10/16/2014] [Indexed: 12/30/2022]
Abstract
Accumulating evidence suggests that neuronal nicotinic acetylcholine receptors (nAChRs) may play a key role in the pathophysiology of some neurological diseases such as epilepsy. Based on genetic studies in patients with epileptic disorders worldwide and animal models of seizure, it has been demonstrated that nAChR activity is altered in some specific types of epilepsy, including autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE) and juvenile myoclonic epilepsy (JME). Neuronal nAChR antagonists also have antiepileptic effects in pre-clinical studies. There is some evidence that conventional antiepileptic drugs may affect neuronal nAChR function. In this review, we re-examine the evidence for the involvement of nAChRs in the pathophysiology of some epileptic disorders, especially ADNFLE and JME, and provide an overview of nAChR antagonists that have been evaluated in animal models of seizure.
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Corradi J, Bouzat C. Understanding the Bases of Function and Modulation of α7 Nicotinic Receptors: Implications for Drug Discovery. Mol Pharmacol 2016; 90:288-99. [PMID: 27190210 DOI: 10.1124/mol.116.104240] [Citation(s) in RCA: 118] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Accepted: 05/05/2016] [Indexed: 01/01/2023] Open
Abstract
The nicotinic acetylcholine receptor (nAChR) belongs to a superfamily of pentameric ligand-gated ion channels involved in many physiologic and pathologic processes. Among nAChRs, receptors comprising the α7 subunit are unique because of their high Ca(2+) permeability and fast desensitization. nAChR agonists elicit a transient ion flux response that is further sustained by the release of calcium from intracellular sources. Owing to the dual ionotropic/metabotropic nature of α7 receptors, signaling pathways are activated. The α7 subunit is highly expressed in the nervous system, mostly in regions implicated in cognition and memory and has therefore attracted attention as a novel drug target. Additionally, its dysfunction is associated with several neuropsychiatric and neurologic disorders, such as schizophrenia and Alzheimer's disease. α7 is also expressed in non-neuronal cells, particularly immune cells, where it plays a role in immunity, inflammation, and neuroprotection. Thus, α7 potentiation has emerged as a therapeutic strategy for several neurologic and inflammatory disorders. With unique activation properties, the receptor is a sensitive drug target carrying different potential binding sites for chemical modulators, particularly agonists and positive allosteric modulators. Although macroscopic and single-channel recordings have provided significant information about the underlying molecular mechanisms and binding sites of modulatory compounds, we know just the tip of the iceberg. Further concerted efforts are necessary to effectively exploit α7 as a drug target for each pathologic situation. In this article, we focus mainly on the molecular basis of activation and drug modulation of α7, key pillars for rational drug design.
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Affiliation(s)
- Jeremías Corradi
- Instituto de Investigaciones Bioquímicas de Bahía Blanca, Universidad Nacional del Sur, CONICET/UNS, Bahía Blanca, Argentina
| | - Cecilia Bouzat
- Instituto de Investigaciones Bioquímicas de Bahía Blanca, Universidad Nacional del Sur, CONICET/UNS, Bahía Blanca, Argentina
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Tabrizian K, Yazdani A, Baheri B, Payandemehr B, Sanati M, Hashemzaei M, Miri A, Zandkarimi M, Belaran M, Fanoudi S, Sharifzadeh M. Zinc Chloride and Lead Acetate-Induced Passive Avoidance Memory Retention Deficits Reversed by Nicotine and Bucladesine in Mice. Biol Trace Elem Res 2016; 169:106-13. [PMID: 26066527 DOI: 10.1007/s12011-015-0399-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2015] [Accepted: 06/03/2015] [Indexed: 10/23/2022]
Abstract
It is very important to investigate the neurotoxic effects of metals on learning and memory processes. In this study, we tried to investigate the effects and time course properties of oral administration of zinc chloride (25, 50, and 75 mg/kg, for 2 weeks), lead acetate (250, 750, 1,500, and 2,500 ppm for 4, 6 and 8 weeks), and their possible mechanisms on a model of memory function. For this matter, we examined the intra-peritoneal injections of nicotine (0.25, 0.5, 1, and 1.5 mg/kg) and bucladesine (50, 100, 300, and 600 nM/mouse) for 4 days alone and in combination with mentioned metals in the step-through passive avoidance task. Control animals received saline, drinking water, saline, and DMSO (dimethyl sulfoxide)/deionized water (1:9), respectively. At the end of each part of studies, animals were trained for 1 day in step-through task. The avoidance memory retention alterations were evaluated 24 and 48 h later in singular and combinational studies. Zinc chloride (75 mg/kg) oral gavage for 2 weeks decreased latency times compared to control animals. Also, lead acetate (750 ppm oral administrations for 8 weeks) caused significant lead blood levels and induced avoidance memory retention impairments. Four-days intra-peritoneal injection of nicotine (1 mg/kg) increased latency time compared to control animals. Finally, findings of this research showed that treatment with intra-peritoneal injections of nicotine (1 mg/kg) and/or bucladesine (600 nM/mouse) reversed zinc chloride- and lead acetate-induced avoidance memory retention impairments. Taken together, these results showed the probable role of cholinergic system and protein kinase A pathways in zinc chloride- and lead acetate-induced avoidance memory alterations.
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Affiliation(s)
- Kaveh Tabrizian
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Zabol University of Medical Sciences, Zabol, Iran
- Medicinal Plants Research Center, Zabol University of Medical Sciences, Zabol, Iran
| | - Abdolmajid Yazdani
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Zabol University of Medical Sciences, Zabol, Iran
| | - Behnam Baheri
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Zabol University of Medical Sciences, Zabol, Iran
| | - Borna Payandemehr
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Tehran University of Medical Sciences, P.O. Box 14155-6451, Tehran, Iran
| | - Mehdi Sanati
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Tehran University of Medical Sciences, P.O. Box 14155-6451, Tehran, Iran
| | - Mahmoud Hashemzaei
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Zabol University of Medical Sciences, Zabol, Iran
| | - Abdolhossein Miri
- Medicinal Plants Research Center, Zabol University of Medical Sciences, Zabol, Iran
- Department of Pharmacognosy, Faculty of Pharmacy, Zabol University of Medical Sciences, Zabol, Iran
| | - Majid Zandkarimi
- Department of Pharmaceutics, Faculty of Pharmacy, Zabol University of Medical Sciences, Zabol, Iran
| | - Maryam Belaran
- Department of Physiology, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Sahar Fanoudi
- Department of Pharmacology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Mohammad Sharifzadeh
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Tehran University of Medical Sciences, P.O. Box 14155-6451, Tehran, Iran.
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Chernyavsky AI, Galitovskiy V, Grando SA. Molecular mechanisms of synergy of corneal muscarinic and nicotinic acetylcholine receptors in upregulation of E-cadherin expression. Int Immunopharmacol 2015; 29:15-20. [DOI: 10.1016/j.intimp.2015.04.036] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Revised: 03/31/2015] [Accepted: 04/17/2015] [Indexed: 12/20/2022]
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Ring A, Strom BO, Turner SR, Timperley CM, Bird M, Green AC, Chad JE, Worek F, Tattersall JEH. Bispyridinium Compounds Inhibit Both Muscle and Neuronal Nicotinic Acetylcholine Receptors in Human Cell Lines. PLoS One 2015; 10:e0135811. [PMID: 26274808 PMCID: PMC4537131 DOI: 10.1371/journal.pone.0135811] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Accepted: 07/27/2015] [Indexed: 11/30/2022] Open
Abstract
Standard treatment of poisoning by organophosphorus anticholinesterases uses atropine to reduce the muscarinic effects of acetylcholine accumulation and oximes to reactivate acetylcholinesterase (the effectiveness of which depends on the specific anticholinesterase), but does not directly address the nicotinic effects of poisoning. Bispyridinium molecules which act as noncompetitive antagonists at nicotinic acetylcholine receptors have been identified as promising compounds and one has been shown to improve survival following organophosphorus poisoning in guinea-pigs. Here, we have investigated the structural requirements for antagonism and compared inhibitory potency of these compounds at muscle and neuronal nicotinic receptors and acetylcholinesterase. A series of compounds was synthesised, in which the length of the polymethylene linker between the two pyridinium moieties was increased sequentially from one to ten carbon atoms. Their effects on nicotinic receptor-mediated calcium responses were tested in muscle-derived (CN21) and neuronal (SH-SY5Y) cells. Their ability to inhibit acetylcholinesterase activity was tested using human erythrocyte ghosts. In both cell lines, the nicotinic response was inhibited in a dose-dependent manner and the inhibitory potency of the compounds increased with greater linker length between the two pyridinium moieties, as did their inhibitory potency for human acetylcholinesterase activity in vitro. These results demonstrate that bispyridinium compounds inhibit both neuronal and muscle nicotinic receptors and that their potency depends on the length of the hydrocarbon chain linking the two pyridinium moieties. Knowledge of structure-activity relationships will aid the optimisation of molecular structures for therapeutic use against the nicotinic effects of organophosphorus poisoning.
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Affiliation(s)
- Avi Ring
- Norwegian Defence Research Establishment, Kjeller, Norway
| | | | - Simon R. Turner
- Dstl Porton Down, Salisbury, Wiltshire, United Kingdom
- Institute for Life Sciences, University of Southampton, Southampton, United Kingdom
| | | | - Michael Bird
- Dstl Porton Down, Salisbury, Wiltshire, United Kingdom
| | | | - John E. Chad
- Institute for Life Sciences, University of Southampton, Southampton, United Kingdom
| | - Franz Worek
- Bundeswehr Institute of Pharmacology and Toxicology, Munich, Germany
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Singh NS, Bernier M, Camandola S, Khadeer MA, Moaddel R, Mattson MP, Wainer IW. Enantioselective inhibition of d-serine transport by (S)-ketamine. Br J Pharmacol 2015; 172:4546-4559. [PMID: 26140427 DOI: 10.1111/bph.13239] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Revised: 06/26/2015] [Accepted: 06/28/2015] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND AND PURPOSE Patients with major depressive disorder receiving racemic ketamine, (R,S)-ketamine, experience transient increases in Clinician-Administered Dissociative States Scale scores and a coincident drop in plasma d-serine levels. The results suggest that (R,S)-ketamine produces an immediate, concentration-dependent pharmacological effect on d-serine plasma concentrations. One potential source of this effect is (R,S)-ketamine-induced inhibition of the transporter ASCT2, which regulates intracellular d-serine concentrations. In this study, we tested this hypothesis by examining the effect of (S)- and (R)-ketamine on ASCT2-mediated transport of d-serine in PC-12 and 1321N1 cells and primary neuronal cells in culture. EXPERIMENTAL APPROACH Intracellular and extracellular d-serine levels were determined using capillary electrophoresis-laser-induced fluorescence and liquid chromatography-mass spectrometry respectively. Expression of ASCT2, Asc-1 and serine racemase was determined utilizing Western blotting. KEY RESULTS (S)-Ketamine produced a concentration-dependent increase in intracellular d-serine and reduced extracellular d-serine accumulation. In contrast, (R)-ketamine decreased both intracellular and extracellular d-serine levels. The ASCT2 inhibitor, benzyl-d-serine (BDS), and ASCT2 gene knockdown mimicked the action of (S)-ketamine on d-serine in PC-12 cells, while the Asc-1 agonist d-isoleucine reduced intracellular d-serine and increased extracellular d-serine accumulation. This response to d-isoleucine was not affected by BDS or (S)-ketamine. Primary cultures of rat neuronal cells expressed ASCT2 and were responsive to (S)-ketamine and BDS. (S)- and (R)-ketamine increased the expression of monomeric serine racemase in all the cells studied, with (S)-ketamine having the greatest effect. CONCLUSIONS AND IMPLICATIONS (S)-Ketamine decreased cellular export of d-serine via selective inhibition of ASCT2, and this could represent a possible source of dissociative effects observed with (R,S)-ketamine.
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Affiliation(s)
- Nagendra S Singh
- Laboratory of Clinical Investigation, National Institute on Aging Intramural Research Program, National Institutes of Health, Baltimore, MD, USA
| | - Michel Bernier
- Translational Gerontology Branch, National Institute on Aging Intramural Research Program, National Institutes of Health, Baltimore, MD, USA
| | - Simonetta Camandola
- Laboratory of Neurosciences, National Institute on Aging Intramural Research Program, National Institutes of Health, Baltimore, MD, USA
| | - Mohammed A Khadeer
- Laboratory of Clinical Investigation, National Institute on Aging Intramural Research Program, National Institutes of Health, Baltimore, MD, USA
| | - Ruin Moaddel
- Laboratory of Clinical Investigation, National Institute on Aging Intramural Research Program, National Institutes of Health, Baltimore, MD, USA
| | - Mark P Mattson
- Laboratory of Neurosciences, National Institute on Aging Intramural Research Program, National Institutes of Health, Baltimore, MD, USA
| | - Irving W Wainer
- Laboratory of Clinical Investigation, National Institute on Aging Intramural Research Program, National Institutes of Health, Baltimore, MD, USA
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Koukouli F, Maskos U. The multiple roles of the α7 nicotinic acetylcholine receptor in modulating glutamatergic systems in the normal and diseased nervous system. Biochem Pharmacol 2015. [PMID: 26206184 DOI: 10.1016/j.bcp.2015.07.018] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Neuronal nicotinic acetylcholine receptors (nAChRs) play an important role in a variety of modulatory and regulatory processes including neurotransmitter release and synaptic transmission in various brain regions of the central nervous system (CNS). Glutamate is the principal excitatory neurotransmitter in the brain and the glutamatergic system participates in the pathophysiology of several neuropsychiatric disorders. Underpinning the importance of nAChRs, many studies demonstrated that nAChRs containing the α7 subunit facilitate glutamate release. Here, we review the currently available body of experimental evidence pertaining to α7 subunit containing nAChRs in their contribution to the modulation of glutamatergic neurotransmission, and we highlight the role of α7 in synaptic plasticity, the morphological and functional maturation of the glutamatergic system and therefore its important contribution in the modulation of neural circuits of the CNS.
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Affiliation(s)
- Fani Koukouli
- Institut Pasteur, Neurobiologie intégrative des systèmes cholinergiques, CNRS UMR 3571, Paris, France.
| | - Uwe Maskos
- Institut Pasteur, Neurobiologie intégrative des systèmes cholinergiques, CNRS UMR 3571, Paris, France.
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ASM-024, a piperazinium compound, promotes the in vitro relaxation of β2-adrenoreceptor desensitized tracheas. PLoS One 2015; 10:e0120095. [PMID: 25799096 PMCID: PMC4370676 DOI: 10.1371/journal.pone.0120095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Accepted: 01/20/2015] [Indexed: 11/30/2022] Open
Abstract
Inhaled β2-adrenoreceptor agonists are widely used in asthma and chronic obstructive pulmonary disease (COPD) for bronchoconstriction relief. β2-adrenoreceptor agonists relax airway smooth muscle cells via cyclic adenosine monophosphate (cAMP) mediated pathways. However, prolonged stimulation induces functional desensitization of the β2-adrenoreceptors (β2-AR), potentially leading to reduced clinical efficacy with chronic or prolonged administration. ASM-024, a small synthetic molecule in clinical stage development, has shown activity at the level of nicotinic receptors and possibly at the muscarinic level and presents anti-inflammatory and bronchodilator properties. Aerosolized ASM-024 reduces airway resistance in mice and promotes in-vitro relaxation of tracheal and bronchial preparations from animal and human tissues. ASM-024 increased in vitro relaxation response to maximally effective concentration of short—acting beta-2 agonists in dog and human bronchi. Although the precise mechanisms by which ASM-024 promotes airway smooth muscle (ASM) relaxation remain unclear, we hypothesized that ASM-024 will attenuate and/or abrogate agonist-induced contraction and remain effective despite β2-AR tachyphylaxis. β2-AR tachyphylaxis was induced with salbutamol, salmeterol and formoterol on guinea pig tracheas. The addition of ASM-024 relaxed concentration-dependently intact or β2-AR desensitized tracheal rings precontracted with methacholine. ASM-024 did not induce any elevation of intracellular cAMP in isolated smooth muscle cells; moreover, blockade of the cAMP pathway with an adenylate cyclase inhibitor had no significant effect on ASM-024-induced guinea pig trachea relaxation. Collectively, these findings show that ASM-024 elicits relaxation of β2-AR desensitized tracheal preparations and suggest that ASM-024 mediates smooth muscle relaxation through a different target and signaling pathway than β2-adrenergic receptor agonists. These findings suggest ASM-024 could potentially provide clinical benefit when used adjunctively with inhaled β2-adrenoreceptor agonists in those patients exhibiting a reduced response to their chronic use.
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Guerra-Álvarez M, Moreno-Ortega AJ, Navarro E, Fernández-Morales JC, Egea J, López MG, Cano-Abad MF. Positive allosteric modulation of alpha-7 nicotinic receptors promotes cell death by inducing Ca(2+) release from the endoplasmic reticulum. J Neurochem 2015; 133:309-19. [PMID: 25650007 DOI: 10.1111/jnc.13049] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Revised: 01/15/2015] [Accepted: 01/16/2015] [Indexed: 12/11/2022]
Abstract
Positive allosteric modulation of α7 isoform of nicotinic acetylcholine receptors (α7-nAChRs) is emerging as a promising therapeutic approach for central nervous system disorders such as schizophrenia or Alzheimer's disease. However, its effect on Ca(2+) signaling and cell viability remains controversial. This study focuses on how the type II positive allosteric modulator (PAM II) PNU120596 affects intracellular Ca(2+) signaling and cell viability. We used human SH-SY5Y neuroblastoma cells overexpressing α7-nAChRs (α7-SH) and their control (C-SH). We monitored cytoplasmic and endoplasmic reticulum (ER) Ca(2+) with Fura-2 and the genetically encoded cameleon targeting the ER, respectively. Nicotinic inward currents were measured using patch-clamp techniques. Viability was assessed using methylthiazolyl blue tetrazolium bromide or propidium iodide staining. We observed that in the presence of a nicotinic agonist, PNU120596 (i) reduced viability of α7-SH but not of C-SH cells; (ii) significantly increased inward nicotinic currents and cytosolic Ca(2+) concentration; (iii) released Ca(2+) from the ER by a Ca(2+) -induced Ca(2+) release mechanism only in α7-SH cells; (iv) was cytotoxic in rat organotypic hippocampal slice cultures; and, lastly, all these effects were prevented by selective blockade of α7-nAChRs, ryanodine receptors, or IP3 receptors. In conclusion, positive allosteric modulation of α7-nAChRs with the PAM II PNU120596 can lead to dysregulation of ER Ca(2+) , overloading of intracellular Ca(2+) , and neuronal cell death. This study focuses on how the type II positive allosteric modulator PNU120596 (PAM II PNU12) affects intracellular Ca(2+) signaling and cell viability. Using SH-SY5Y neuroblastoma cells overexpressing α7-nAChRs (α7-SH) and their control (C-SH), we find that PAM of α7-nAChRs with PNU120596: (i) increases inward calcium current (ICa ) and cytosolic Ca(2+) concentration ([Ca(2+) ]cyt ); (ii) releases Ca(2+) from the ER ([Ca(2+) ]ER ) by a Ca(2+) -induced Ca(2+) release mechanism; and (iv) reduces cell viability. These findings were corroborated in rat hippocampal organotypic cultures. [Ca(2+) ]cyt , cytosolic Ca(2+) concentration; [Ca(2+) ]ER , endoplasmic reticulum Ca(2+) concentration; α7 nAChR, α7 isoform of nicotinic acetylcholine receptors; α7-SH, SH-SY5Y stably overexpressing α7 nAChRs cells; C-SH, control SH-SY5Y cells; Nic, nicotine; PNU12, PNU120596.
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Affiliation(s)
- María Guerra-Álvarez
- Servicio de Farmacología Clínica, Instituto de Investigación Sanitaria, Hospital Universitario de la Princesa, Madrid, Spain
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Hernández-Vázquez F, Chavarría K, Garduño J, Hernández-López S, Mihailescu SP. Nicotine increases GABAergic input on rat dorsal raphe serotonergic neurons through alpha7 nicotinic acetylcholine receptor. J Neurophysiol 2014; 112:3154-63. [DOI: 10.1152/jn.00223.2014] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The dorsal raphe nucleus (DRN) contains large populations of serotonergic (5-HT) neurons. This nucleus receives GABAergic inhibitory afferents from many brain areas and from DRN interneurons. Both GABAergic and 5-HT DRN neurons express functional nicotinic acetylcholine receptors (nAChRs). Previous studies have demonstrated that nicotine increases 5-HT release and 5-HT DRN neuron discharge rate by stimulating postsynaptic nAChRs and by increasing glutamate and norepinephrine release inside DRN. However, the influence of nicotine on the GABAergic input to 5-HT DRN neurons was poorly investigated. Therefore, the aim of this work was to determine the effect of nicotine on GABAergic spontaneous inhibitory postsynaptic currents (sIPSCs) of 5-HT DRN neurons and the subtype of nAChR(s) involved in this response. Experiments were performed in coronal slices obtained from young Wistar rats. GABAergic sIPSCs were recorded from post hoc-identified 5-HT DRN neurons with the whole cell voltage patch-clamp technique. Administration of nicotine (1 μM) increased sIPSC frequency in 72% of identified 5-HT DRN neurons. This effect was not reproduced by the α4β2 nAChR agonist RJR-2403 and was not influenced by TTX (1 μM). It was mimicked by the selective agonist for α7 nAChR, PNU-282987, and exacerbated by the positive allosteric modulator of the same receptor, PNU-120596. The nicotine-induced increase in sIPSC frequency was independent on voltage-gated calcium channels and dependent on Ca2+-induced Ca2+ release (CICR). These results demonstrate that nicotine increases the GABAergic input to most 5-HT DRN neurons, by activating α7 nAChRs and producing CICR in DRN GABAergic terminals.
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Affiliation(s)
- F. Hernández-Vázquez
- Departamento de Fisiología, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - K. Chavarría
- Departamento de Fisiología, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - J. Garduño
- Departamento de Fisiología, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - S. Hernández-López
- Departamento de Fisiología, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - S. P. Mihailescu
- Departamento de Fisiología, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City, Mexico
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Wu CYC, Lee RHC, Chen PY, Tsai APY, Chen MF, Kuo JS, Lee TJF. L-type calcium channels in sympathetic α3β2-nAChR-mediated cerebral nitrergic neurogenic vasodilation. Acta Physiol (Oxf) 2014; 211:544-58. [PMID: 24825168 DOI: 10.1111/apha.12315] [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: 12/02/2013] [Revised: 12/22/2013] [Accepted: 05/08/2014] [Indexed: 10/25/2022]
Abstract
AIM Nicotine stimulation of α3β2-nicotinic acetylcholine receptors (α3β2-nAChRs) located on sympathetic nerves innervating basilar arteries causes calcium-dependent noradrenaline release, leading to activation of parasympathetic nitrergic nerves and dilation of basilar arteries. This study aimed to investigate the major subtype of calcium channels located on cerebral peri-vascular sympathetic nerves, which is involved in nicotine-induced α3β2-nAChR-mediated nitrergic vasodilation in basilar arteries. METHODS Nicotine- and transmural nerve stimulation (TNS)-induced dilation of isolated porcine basilar arteries was examined using in vitro tissue bath. Nicotine-induced calcium influx, nicotine-induced noradrenaline release and nicotine-induced inward currents were evaluated in rat superior cervical ganglion (SCG) neurones, peri-vascular sympathetic nerves of porcine basilar arteries and α3β2-nAChRs-expressing oocytes respectively. mRNA and protein expression of Cav 1.2 and Cav 1.3 channels were detected by RT-PCR, Western blotting and immunohistochemistry. RESULTS Nicotine-induced vasodilation was not affected by ω-agatoxin TK (selective P/Q-type calcium channel blocker) or ω-conotoxin GVIA (N-type calcium channel blocker). The vasodilation, however, was inhibited by nicardipine (L-type calcium channel blocker) in concentrations which did not affect TNS-induced vasodilation, suggesting the specific blockade. Nicardipine concentration-dependently inhibited nicotine-induced calcium influx in rat SCG neurones and reduced nicotine-induced noradrenaline release from peri-vascular sympathetic nerves of porcine basilar arteries. Nicardipine (10 μm), which significantly blocked nicotine-induced vasorelaxation by 70%, did not appreciably affect nicotine-induced inward currents in α3β2-nAChRs-expressing oocytes. Furthermore, the mRNAs and proteins of Cav 1.2 and Cav 1.3 channels were expressed in porcine SCG and peri-vascular nerve terminals. CONCLUSION The sympathetic neuronal calcium influx through L-type calcium channels is modulated by α3β2-nAChRs. This calcium influx causes noradrenaline release, initiating sympathetic-parasympathetic (axo-axonal) interaction-induced nitrergic dilation of porcine basilar arteries.
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Affiliation(s)
- C. Y.-C. Wu
- Institute of Pharmacology & Toxicology; Tzu Chi University; Hualien Taiwan
- Center for Vascular Medicine; College of Life Sciences; Tzu Chi University; Hualien Taiwan
| | - R. H.-C. Lee
- Center for Vascular Medicine; College of Life Sciences; Tzu Chi University; Hualien Taiwan
- Institute of Medical Sciences; College of Medicine; Tzu Chi University; Hualien Taiwan
| | - P.-Y. Chen
- Institute of Pharmacology & Toxicology; Tzu Chi University; Hualien Taiwan
- Department of Medical Research; Buddhist Tzu Chi General Hospital; Hualien Taiwan
| | - A. P.-Y. Tsai
- Institute of Pharmacology & Toxicology; Tzu Chi University; Hualien Taiwan
- Center for Vascular Medicine; College of Life Sciences; Tzu Chi University; Hualien Taiwan
| | - M.-F. Chen
- Center for Vascular Medicine; College of Life Sciences; Tzu Chi University; Hualien Taiwan
- Department of Medical Research; Buddhist Tzu Chi General Hospital; Hualien Taiwan
| | - J.-S. Kuo
- Center for Vascular Medicine; College of Life Sciences; Tzu Chi University; Hualien Taiwan
- Institute of Medical Sciences; College of Medicine; Tzu Chi University; Hualien Taiwan
| | - T. J.-F. Lee
- Institute of Pharmacology & Toxicology; Tzu Chi University; Hualien Taiwan
- Center for Vascular Medicine; College of Life Sciences; Tzu Chi University; Hualien Taiwan
- Institute of Medical Sciences; College of Medicine; Tzu Chi University; Hualien Taiwan
- Department of Medical Research; Buddhist Tzu Chi General Hospital; Hualien Taiwan
- Department of Life Sciences; Tzu Chi University; Hualien Taiwan. Department of Pharmacology; Southern Illinois University School of Medicine; Springfield IL USA
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Brown JL, Wonnacott S. Sazetidine-A Activates and Desensitizes Native α7 Nicotinic Acetylcholine Receptors. Neurochem Res 2014; 40:2047-54. [PMID: 24728867 PMCID: PMC4630245 DOI: 10.1007/s11064-014-1302-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Revised: 03/24/2014] [Accepted: 04/01/2014] [Indexed: 12/24/2022]
Abstract
The aim of this study was to investigate the ability of sazetidine-A, a novel partial agonist at α4β2 nicotinic acetylcholine receptors (nAChRs), to affect the function of native α7 nAChRs in SH-SY5Y cells and primary cortical cultures. The α7-selective positive allosteric modulator PNU-120596 was used to reveal receptor activation, measured as an increase in intracellular calcium using fluorescent indicators. In the absence of PNU-120596, sazetidine-A elicited mecamylamine-sensitive increases in fluorescence in SH-SY5Y cells (EC50 4.2 µM) but no responses from primary cortical neurons. In the presence on PNU-120596, an additional response to sazetidine-A was observed in SH-SY5Y cells (EC50 0.4 µM) and robust responses were recorded in 14 % of cortical neurons. These PNU-120596-dependent responses were blocked by methyllycaconitine, consistent with the activation of α7 nAChRs. Preincubtion with sazetidine-A concentration-dependently attenuated subsequent responses to the α7-selective agonist PNU-282987 in SH-SY5Y cells (IC50 476 nM) and cortical cultures. These findings support the ability of sazetidine-A to interact with α7 nAChRs, which may contribute to sazetidine-A’s actions in complex physiological systems.
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Affiliation(s)
- Jack L Brown
- Department of Biology and Biochemistry, University of Bath, Bath, BA2 7AY, UK
| | - Susan Wonnacott
- Department of Biology and Biochemistry, University of Bath, Bath, BA2 7AY, UK.
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