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Sanjay, Sood R, Jaiswal V, Kang SU, Park M, Lee HJ. Nobiletin regulates intracellular Ca 2+ levels via IP 3R and ameliorates neuroinflammation in Aβ42-induced astrocytes. Redox Biol 2024; 73:103197. [PMID: 38781730 PMCID: PMC11145555 DOI: 10.1016/j.redox.2024.103197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2024] [Revised: 05/12/2024] [Accepted: 05/15/2024] [Indexed: 05/25/2024] Open
Abstract
Astrocytes are the major glial cells in the human brain and provide crucial metabolic and trophic support to neurons. The amyloid-β peptide (Aβ) alter the morphological and functional properties of astrocytes and induce inflammation and calcium dysregulation, contributing to Alzheimer's disease (AD) pathology. Recent studies highlight the role of Toll-like receptor (TLR) 4/nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signaling in inflammation. Reactive oxygen species (ROS) generated due to Aβ, induce apoptosis in the brain cells worsening AD progression. Astrocytic cell surface receptors, such as purinergic receptors (P2Y1 and P2Y2), metabotropic glutamate receptor (mGLUR)5, α7 nicotinic acetylcholine receptor (α7nAChR), and N-methyl-d-aspartate receptors (NMDARs), have been suggested to interact with inositol trisphosphate receptor (IP3R) on the endoplasmic reticulum (ER) to induce Ca2+ movement from ER to cytoplasm, causing Ca2+ dysregulation. We found that the citrus flavonoid nobiletin (NOB) protected primary astrocytes from Aβ42-induced cytotoxicity and inhibited TLR4/NF-κB signaling in Aβ42-induced primary rat astrocytes. NOB was found to regulate Aβ42-induced ROS levels through Keap1-Nrf2 pathway. The receptors P2Y1, P2Y2, mGLUR5, α7nAChR, and NMDARs induced intracellular Ca2+ levels by activating IP3R and NOB regulated them, thereby regulating intracellular Ca2+ levels. Molecular docking analysis revealed a possible interaction between NOB and IP3R in IP3R regulation. Furthermore, RNA sequencing revealed various NOB-mediated biological signaling pathways, such as the AD-presenilin, AD-amyloid secretase, and Wnt signaling pathway, suggesting possible neuroprotective roles of NOB. To conclude, NOB is a promising therapeutic agent for AD and works by modulating AD pathology at various levels in Aβ42-induced primary rat astrocytes.
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Affiliation(s)
- Sanjay
- Institute for Aging and Clinical Nutrition Research, Gachon University, Seongnam, Gyeonggi-do, 13120, Republic of Korea.
| | - Rachit Sood
- Institute for Aging and Clinical Nutrition Research, Gachon University, Seongnam, Gyeonggi-do, 13120, Republic of Korea; Department of Food and Nutrition, College of BioNano Technology, Gachon University, Seongnam, Gyeonggi-do, 13120, Republic of Korea.
| | - Varun Jaiswal
- Institute for Aging and Clinical Nutrition Research, Gachon University, Seongnam, Gyeonggi-do, 13120, Republic of Korea; Department of Food and Nutrition, College of BioNano Technology, Gachon University, Seongnam, Gyeonggi-do, 13120, Republic of Korea.
| | - Sung-Ung Kang
- Neuroregeneration and Stem Cell Programs, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA; Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
| | - Miey Park
- Institute for Aging and Clinical Nutrition Research, Gachon University, Seongnam, Gyeonggi-do, 13120, Republic of Korea; Department of Food and Nutrition, College of BioNano Technology, Gachon University, Seongnam, Gyeonggi-do, 13120, Republic of Korea.
| | - Hae-Jeung Lee
- Institute for Aging and Clinical Nutrition Research, Gachon University, Seongnam, Gyeonggi-do, 13120, Republic of Korea; Department of Food and Nutrition, College of BioNano Technology, Gachon University, Seongnam, Gyeonggi-do, 13120, Republic of Korea; Department of Health Sciences and Technology, GAIHST, Gachon University, Incheon, 21999, Republic of Korea.
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2
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Cha J, Choi S. Gene-Smoking Interaction Analysis for the Identification of Novel Asthma-Associated Genetic Factors. Int J Mol Sci 2023; 24:12266. [PMID: 37569643 PMCID: PMC10419280 DOI: 10.3390/ijms241512266] [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: 07/01/2023] [Revised: 07/26/2023] [Accepted: 07/30/2023] [Indexed: 08/13/2023] Open
Abstract
Asthma is a complex heterogeneous disease caused by gene-environment interactions. Although numerous genome-wide association studies have been conducted, these interactions have not been systemically investigated. We sought to identify genetic factors associated with the asthma phenotype in 66,857 subjects from the Health Examination Study, Cardiovascular Disease Association Study, and Korea Association Resource Study cohorts. We investigated asthma-associated gene-environment (smoking status) interactions at the level of single nucleotide polymorphisms, genes, and gene sets. We identified two potentially novel (SETDB1 and ZNF8) and five previously reported (DM4C, DOCK8, MMP20, MYL7, and ADCY9) genes associated with increased asthma risk. Numerous gene ontology processes, including regulation of T cell differentiation in the thymus (GO:0033081), were significantly enriched for asthma risk. Functional annotation analysis confirmed the causal relationship between five genes (two potentially novel and three previously reported genes) and asthma through genome-wide functional prediction scores (combined annotation-dependent depletion, deleterious annotation of genetic variants using neural networks, and RegulomeDB). Our findings elucidate the genetic architecture of asthma and improve the understanding of its biological mechanisms. However, further studies are necessary for developing preventive treatments based on environmental factors and understanding the immune system mechanisms that contribute to the etiology of asthma.
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Affiliation(s)
- Junho Cha
- Department of Applied Artificial Intelligence, College of Computing, Hanyang University, 55 Hanyang-daehak-ro, Sangnok-gu, Ansan 15588, Republic of Korea;
| | - Sungkyoung Choi
- Department of Applied Artificial Intelligence, College of Computing, Hanyang University, 55 Hanyang-daehak-ro, Sangnok-gu, Ansan 15588, Republic of Korea;
- Department of Mathematical Data Science, College of Science and Convergence Technology, Hanyang University, 55 Hanyang-daehak-ro, Sangnok-gu, Ansan 15588, Republic of Korea
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3
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Hone AJ, McIntosh JM. Nicotinic acetylcholine receptors: Therapeutic targets for novel ligands to treat pain and inflammation. Pharmacol Res 2023; 190:106715. [PMID: 36868367 PMCID: PMC10691827 DOI: 10.1016/j.phrs.2023.106715] [Citation(s) in RCA: 25] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 02/22/2023] [Accepted: 02/28/2023] [Indexed: 03/05/2023]
Abstract
Nicotinic acetylcholine receptors (nAChRs) have been historically defined as ligand-gated ion channels and function as such in the central and peripheral nervous systems. Recently, however, non-ionic signaling mechanisms via nAChRs have been demonstrated in immune cells. Furthermore, the signaling pathways where nAChRs are expressed can be activated by endogenous ligands other than the canonical agonists acetylcholine and choline. In this review, we discuss the involvement of a subset of nAChRs containing α7, α9, and/or α10 subunits in the modulation of pain and inflammation via the cholinergic anti-inflammatory pathway. Additionally, we review the most recent advances in the development of novel ligands and their potential as therapeutics.
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Affiliation(s)
- Arik J Hone
- School of Biological Sciences University of Utah, Salt Lake City, UT, USA; MIRECC, George E. Whalen Veterans Affairs Medical Center, Salt Lake City, UT, USA.
| | - J Michael McIntosh
- School of Biological Sciences University of Utah, Salt Lake City, UT, USA; Department of Psychiatry, University of Utah, Salt Lake City, UT, USA; George E. Whalen Veterans Affairs Medical Center, Salt Lake City, UT, USA.
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4
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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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5
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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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Wu M, Liu CZ, Barrall EA, Rissman RA, Joiner WJ. Unbalanced Regulation of α7 nAChRs by Ly6h and NACHO Contributes to Neurotoxicity in Alzheimer's Disease. J Neurosci 2021; 41:8461-8474. [PMID: 34446574 PMCID: PMC8513707 DOI: 10.1523/jneurosci.0494-21.2021] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 08/17/2021] [Accepted: 08/19/2021] [Indexed: 12/24/2022] Open
Abstract
α7 nicotinic acetylcholine receptors (nAChRs) are widely expressed in the brain where they promote fast cholinergic synaptic transmission and serve important neuromodulatory functions. However, their high permeability to Ca2+ also predisposes them to contribute to disease states. Here, using transfected HEK-tsa cells and primary cultured hippocampal neurons from male and female rats, we demonstrate that two proteins called Ly6h and NACHO compete for access to α7 subunits, operating together but in opposition to maintain α7 assembly and activity within a narrow range that is optimal for neuronal function and viability. Using mixed gender human temporal cortex and cultured hippocampal neurons from rats we further show that this balance is perturbed during Alzheimer's disease (AD) because of amyloid β (Aβ)-driven reduction in Ly6h, with severe reduction leading to increased phosphorylated tau and α7-mediated neurotoxicity. Ly6h release into human CSF is also correlated with AD severity. Thus, Ly6h links cholinergic signaling, Aβ and phosphorylated tau and may serve as a novel marker for AD progression.SIGNIFICANCE STATEMENT One of the earliest and most persistent hypotheses regarding Alzheimer's disease (AD) attributes cognitive impairment to loss of cholinergic signaling. More recently, interest has focused on crucial roles for amyloid β (Aβ) and phosphorylated tau in Alzheimer's pathogenesis. Here, we demonstrate that these elements are linked by Ly6h and its counterpart, NACHO, functioning in opposition to maintain assembly of nicotinic acetylcholine receptors (nAChRs) within the physiological range. Our data suggests that Aβ shifts the balance away from Ly6h and toward NACHO, resulting in increased assembly of Ca2+-permeable nAChRs and thus a conversion of basal cholinergic to neurotoxic signaling.
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Affiliation(s)
- Meilin Wu
- Department of Pharmacology, University of California San Diego, La Jolla, California 92093
| | - Clifford Z Liu
- Department of Pharmacology, University of California San Diego, La Jolla, California 92093
| | - Erika A Barrall
- Department of Pharmacology, University of California San Diego, La Jolla, California 92093
| | - Robert A Rissman
- Department of Neurosciences, University of California San Diego, La Jolla, California 92093
- Alzheimer's Disease Research Center, University of California San Diego, La Jolla, California 92093
| | - William J Joiner
- Department of Pharmacology, University of California San Diego, La Jolla, California 92093
- Center for Circadian Biology, University of California San Diego, La Jolla, California 92093
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7
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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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Wang X, Xiao H, Wang J, Huang Z, Peng G, Xie W, Bian X, Liu H, Shi C, Yang T, Li X, Gao J, Meng Y, Jiang Q, Chen W, Hu F, Wei N, Wang X, Zhang L, Wang K, Sun Q. Synthesis and Biological Evaluation of Novel Triazine Derivatives as Positive Allosteric Modulators of α7 Nicotinic Acetylcholine Receptors. J Med Chem 2021; 64:12379-12396. [PMID: 34374537 DOI: 10.1021/acs.jmedchem.1c01058] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Enhancing neuronal α7 nicotinic acetylcholine receptor (α7 nAChR) function can alleviate cognitive deficits. Here, we report the design, synthesis, and evaluation of N-(4-(trifluoromethoxy)phenyl)-1,3,5-triazin-2-amine derivatives 8-10 as a series of novel α7 nAChR positive allosteric modulators (PAMs). The representative compound 10e functions as a type I PAM with an EC50 of 3.0 μM and approximately 38-fold enhancement of α7 current in the presence of agonist acetylcholine (100 μM). It specifically enhances α7 current with high selectivity. Compound 10e shows good pharmacokinetic property in mice. Intraperitoneal injection of 10e (3 mg/kg) exhibits sufficient blood-brain barrier penetration in mice. Furthermore, 10e can also rescue the auditory gating deficit in mice with schizophrenia-like behavior. Molecular docking of 10e with homopentameric α7 nAChR reveals a new mode of action. These results support the potential of 10e for treatment for schizophrenia and Alzheimer's disease.
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Affiliation(s)
- Xintong Wang
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing 100191, China
- Department of Molecualr and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University, Beijing 100191, China
| | - Haoran Xiao
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing 100191, China
| | - Jing Wang
- Department of Pharmacology, School of Pharmacy, Qingdao University Medical College, #1 Ningde Road, Qingdao 266073, China
| | - Zongze Huang
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing 100191, China
| | - Geng Peng
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing 100191, China
| | - Wenjun Xie
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing 100191, China
- Department of Molecualr and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University, Beijing 100191, China
| | - Xiling Bian
- Department of Molecualr and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University, Beijing 100191, China
| | - Huijie Liu
- Department of Pharmacology, School of Pharmacy, Qingdao University Medical College, #1 Ningde Road, Qingdao 266073, China
| | - Cheng Shi
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing 100191, China
| | - Taoyi Yang
- Department of Molecualr and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University, Beijing 100191, China
| | - Xin Li
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing 100191, China
| | - Jian Gao
- Department of Molecualr and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University, Beijing 100191, China
| | - Ying Meng
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing 100191, China
| | - Qianchen Jiang
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing 100191, China
| | - Wei Chen
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing 100191, China
| | - Fang Hu
- Department of Pharmacology, School of Pharmacy, Qingdao University Medical College, #1 Ningde Road, Qingdao 266073, China
| | - Ningning Wei
- Department of Pharmacology, School of Pharmacy, Qingdao University Medical College, #1 Ningde Road, Qingdao 266073, China
- Institute of Innovative Drugs, Qingdao University, 38 Dengzhou Road, Qingdao 266021, China
| | - Xiaowei Wang
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing 100191, China
| | - Liangren Zhang
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing 100191, China
| | - KeWei Wang
- Department of Pharmacology, School of Pharmacy, Qingdao University Medical College, #1 Ningde Road, Qingdao 266073, China
- Institute of Innovative Drugs, Qingdao University, 38 Dengzhou Road, Qingdao 266021, China
| | - Qi Sun
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing 100191, China
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Abstract
The α7-type nicotinic acetylcholine receptor is one of the most unique and interesting of all the members of the cys-loop superfamily of ligand-gated ion channels. Since it was first identified initially as a binding site for α-bungarotoxin in mammalian brain and later as a functional homomeric receptor with relatively high calcium permeability, it has been pursued as a potential therapeutic target for numerous indications, from Alzheimer disease to asthma. In this review, we discuss the history and state of the art for targeting α7 receptors, beginning with subtype-selective agonists and the basic pharmacophore for the selective activation of α7 receptors. A key feature of α7 receptors is their rapid desensitization by standard "orthosteric" agonist, and we discuss insights into the conformational landscape of α7 receptors that has been gained by the development of ligands binding to allosteric sites. Some of these sites are targeted by positive allosteric modulators that have a wide range of effects on the activation profile of the receptors. Other sites are targeted by direct allosteric agonist or antagonists. We include a perspective on the potential importance of α7 receptors for metabotropic as well as ionotropic signaling. We outline the challenges that exist for future development of drugs to target this important receptor and approaches that may be considered to address those challenges. SIGNIFICANCE STATEMENT: The α7-type nicotinic acetylcholine receptor (nAChR) is acknowledged as a potentially important therapeutic target with functional properties associated with both ionotropic and metabotropic signaling. The functional properties of α7 nAChR can be regulated in diverse ways with the variety of orthosteric and allosteric ligands described in this review.
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Affiliation(s)
- Roger L Papke
- Departments of Pharmacology and Therapeutics (R.L.P) and Chemistry (N.A.H.), University of Florida, Gainesville, FL
| | - Nicole A Horenstein
- Departments of Pharmacology and Therapeutics (R.L.P) and Chemistry (N.A.H.), University of Florida, Gainesville, FL
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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: 29] [Impact Index Per Article: 7.3] [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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Uwada J, Nakazawa H, Mikami D, Islam MS, Muramatsu I, Taniguchi T, Yazawa T. PNU-120596, a positive allosteric modulator of α7 nicotinic acetylcholine receptor, directly inhibits p38 MAPK. Biochem Pharmacol 2020; 182:114297. [DOI: 10.1016/j.bcp.2020.114297] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 10/19/2020] [Accepted: 10/20/2020] [Indexed: 10/23/2022]
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12
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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: 3] [Impact Index Per Article: 0.8] [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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13
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Maldifassi MC, Momboisse F, Guerra MJ, Vielma AH, Maripillán J, Báez-Matus X, Flores-Muñoz C, Cádiz B, Schmachtenberg O, Martínez AD, Cárdenas AM. The interplay between α7 nicotinic acetylcholine receptors, pannexin-1 channels and P2X7 receptors elicit exocytosis in chromaffin cells. J Neurochem 2020; 157:1789-1808. [PMID: 32931038 DOI: 10.1111/jnc.15186] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 08/18/2020] [Accepted: 09/04/2020] [Indexed: 12/20/2022]
Abstract
Pannexin-1 (Panx1) forms plasma membrane channels that allow the exchange of small molecules between the intracellular and extracellular compartments, and are involved in diverse physiological and pathological responses in the nervous system. However, the signaling mechanisms that induce their opening still remain elusive. Here, we propose a new mechanism for Panx1 channel activation through a functional crosstalk with the highly Ca2+ permeable α7 nicotinic acetylcholine receptor (nAChR). Consistent with this hypothesis, we found that activation of α7 nAChRs induces Panx1-mediated dye uptake and ATP release in the neuroblastoma cell line SH-SY5Y-α7. Using membrane permeant Ca2+ chelators, total internal reflection fluorescence microscopy in SH-SY5Y-α7 cells expressing a membrane-tethered GCAMP3, and Src kinase inhibitors, we further demonstrated that Panx1 channel opening depends on Ca2+ signals localized in submembrane areas, as well as on Src kinases. In turn, Panx1 channels amplify cytosolic Ca2+ signals induced by the activation of α7 nAChRs, by a mechanism that seems to involve ATP release and P2X7 receptor activation, as hydrolysis of extracellular ATP with apyrase or blockage of P2X7 receptors with oxidized ATP significantly reduces the α7 nAChR-Ca2+ signal. The physiological relevance of this crosstalk was also demonstrated in neuroendocrine chromaffin cells, wherein Panx1 channels and P2X7 receptors contribute to the exocytotic release of catecholamines triggered by α7 nAChRs, as measured by amperometry. Together these findings point to a functional coupling between α7 nAChRs, Panx1 channels and P2X7 receptors with physiological relevance in neurosecretion.
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Affiliation(s)
- María C Maldifassi
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | | | - María J Guerra
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Alex H Vielma
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Jaime Maripillán
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Ximena Báez-Matus
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Carolina Flores-Muñoz
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile.,Programa de Doctorado en Ciencias, Universidad de Valparaíso, Chile
| | - Bárbara Cádiz
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile.,Programa de Magister en Ciencias Biológicas, Universidad de Valparaíso, Chile
| | - Oliver Schmachtenberg
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Agustín D Martínez
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Ana M Cárdenas
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
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14
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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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15
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Nielsen BE, Bermudez I, Bouzat C. Flavonoids as positive allosteric modulators of α7 nicotinic receptors. Neuropharmacology 2019; 160:107794. [PMID: 31560909 DOI: 10.1016/j.neuropharm.2019.107794] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Revised: 08/09/2019] [Accepted: 09/23/2019] [Indexed: 12/11/2022]
Abstract
The use of positive allosteric modulators (PAM) of α7 nicotinic receptors is a promising therapy for neurodegenerative, inflammatory and cognitive disorders. Flavonoids are polyphenolic compounds showing neuroprotective, anti-inflammatory and pro-cognitive actions. Besides their well-known antioxidant activity, flavonoids trigger intracellular pathways and interact with receptors, including α7. To reveal how the beneficial actions of flavonoids are linked to α7 function, we evaluated the effects of three representative flavonoids -genistein, quercetin and the neoflavonoid 5,7-dihydroxy-4-phenylcoumarin- on whole-cell and single-channel currents. All flavonoids increase the maximal currents elicited by acetylcholine with minimal effects on desensitization and do not reactivate desensitized receptors, a behaviour consistent with type I PAMs. At the single-channel level, they increase the duration of the open state and produce activation in long-duration episodes with a rank order of efficacy of genistein > quercetin ≥ neoflavonoid. By using mutant and chimeric α7 receptors, we demonstrated that flavonoids share transmembrane structural determinants with other PAMs. The α7-PAM activity of flavonoids results in decreased cell levels of reactive oxygen species. Thus, allosteric potentiation of α7 may be an additional mechanism underlying neuroprotective actions of flavonoids, which may be used as scaffolds for designing new therapeutic agents.
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Affiliation(s)
- Beatriz Elizabeth Nielsen
- Instituto de Investigaciones Bioquímicas de Bahía Blanca, Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Bahía Blanca 8000, Argentina
| | - Isabel Bermudez
- Department of Medical and Biological Sciences, Oxford Brookes University, Oxford, OX3 0BP, United Kingdom
| | - Cecilia Bouzat
- Instituto de Investigaciones Bioquímicas de Bahía Blanca, Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Bahía Blanca 8000, Argentina.
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16
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Li X, Xie W, Wang X, Huang Z, Bian X, Wang K, Sun Q. Chemical conversion of nicotinamide into type I positive allosteric modulator of α7 nAChRs. Bioorg Med Chem Lett 2019; 29:1928-1933. [PMID: 31153804 DOI: 10.1016/j.bmcl.2019.05.046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 05/08/2019] [Accepted: 05/22/2019] [Indexed: 11/25/2022]
Abstract
Structural modifications of nicotinamide, a form of vitamin B3, gave rise to a series of compounds (8aa-8ce) that exhibit activities as type I positive allosteric modulators (PAMs) of human α7 nAChR expressed in Xenopus oocytes in two-electrode voltage clamp assay. The compound 8ai was a potent and efficacious PAM with an EC50 = 3.34 ± 1.13 μM and the maximum activation effect of α7 current over 1474 ± 246% in the presence of acetylcholine (100 μM). It is highly specific to α7 nAChR over other subtypes of nAChR and 5-HT3A receptors. The structure-activity relationship analysis identified a key skeleton of nicotinamide nucleus critical for biological activity. Taken together, the 8ai as a type I PAM of α7 nAChR may be beneficial for improvement of cognitive deficit.
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Affiliation(s)
- Xin Li
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing 100191, China
| | - Wenjun Xie
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing 100191, China; Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University, Beijing 100191, China
| | - Xintong Wang
- Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University, Beijing 100191, China
| | - Zongze Huang
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing 100191, China
| | - Xiling Bian
- Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University, Beijing 100191, China
| | - KeWei Wang
- Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University, Beijing 100191, China; Department of Pharmacology, School of Pharmacy, Qingdao University, Qingdao 266021, China.
| | - Qi Sun
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing 100191, China.
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17
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Bali ZK, Nagy LV, Budai D, Hernádi I. Facilitation and inhibition of firing activity and N-methyl-D-aspartate-evoked responses of CA1 hippocampal pyramidal cells by alpha7 nicotinic acetylcholine receptor selective compounds in vivo. Sci Rep 2019; 9:9324. [PMID: 31249369 PMCID: PMC6597544 DOI: 10.1038/s41598-019-45796-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Accepted: 06/10/2019] [Indexed: 12/22/2022] Open
Abstract
Alpha7 nicotinic acetylcholine receptors (nAChRs) are promising novel targets for the treatment of neurocognitive disorders. Although the cognitive enhancer potential of alpha7 nAChR agonists and positive allosteric modulators (PAMs) has been confirmed in several preclinical animal models, there are only sparse in vivo electrophysiological data on their effects on the firing activity and excitability of neurons. The present study investigated and compared local effects of alpha7 nAChR agonist PHA-543613 and PAMs PNU-120596 and NS-1738 on the spontaneous and N-methyl-D-aspartate-evoked (NMDA-evoked) firing rate of rat CA1 hippocampal pyramidal cells, in vivo. Furthermore, effects of alpha7 nAChR antagonist methyllycaconitine (MLA) and GABA were also tested. Results showed substantially different effects of the alpha7 nAChR agonist and PAMs. While PNU-120596 and NS-1738 predominantly and significantly increased both spontaneous and NMDA-evoked firing rate of the neurons, application of PHA-543613 resulted in almost equal distribution of facilitatory and inhibitory effects. The increase of the NMDA-evoked firing rate exerted by NS-1738 was superadditive over the sum of the single effects of NMDA and NS-1738. The simultaneous application of alpha7 nAChR agonist PHA-543613 and PAM NS-1738 resulted in additive increase of both spontaneous and NMDA-evoked firing rate. However, NS-1738 counteracted inhibitory effects of PHA-543613 in 5 out of 6 neurons, resulting in a synergistic potentiation of their firing responses to NMDA. Our results suggest that alpha7 nAChR PAMs increase neuronal excitability more potently than agonists, while the remarkable occurrence of inhibitory effects of PHA-543613 (possibly originating from receptor desensitization) implies that agonists may exert neuroprotective effects.
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Affiliation(s)
- Zsolt Kristóf Bali
- Department of Experimental Zoology and Neurobiology, Faculty of Sciences, University of Pécs, Pécs, Hungary.,János Szentágothai Research Center, Center for Neuroscience, University of Pécs, Pécs, Hungary.,Grastyán Endre Translational Research Center, University of Pécs, Pécs, Hungary
| | - Lili Veronika Nagy
- Department of Experimental Zoology and Neurobiology, Faculty of Sciences, University of Pécs, Pécs, Hungary.,János Szentágothai Research Center, Center for Neuroscience, University of Pécs, Pécs, Hungary
| | - Dénes Budai
- Kation Scientific LLC, Minneapolis, Minnesota, USA
| | - István Hernádi
- Department of Experimental Zoology and Neurobiology, Faculty of Sciences, University of Pécs, Pécs, Hungary. .,János Szentágothai Research Center, Center for Neuroscience, University of Pécs, Pécs, Hungary. .,Institute of Physiology, Medical School, University of Pécs, Pécs, Hungary. .,Grastyán Endre Translational Research Center, University of Pécs, Pécs, Hungary.
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18
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Quadri M, Bagdas D, Toma W, Stokes C, Horenstein NA, Damaj MI, Papke RL. The Antinociceptive and Anti-Inflammatory Properties of the α7 nAChR Weak Partial Agonist p-CF 3 N, N-diethyl- N'-phenylpiperazine. J Pharmacol Exp Ther 2018; 367:203-214. [PMID: 30111636 DOI: 10.1124/jpet.118.249904] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Accepted: 08/13/2018] [Indexed: 12/13/2022] Open
Abstract
Chronic pain and inflammatory diseases can be regulated by complex mechanisms involving α7 nicotinic acetylcholine receptors (nAChRs), making this subtype a promising drug target for anti-inflammatory therapies. Recent evidence suggests that suchtreatment of inflammatory pain may rely on metabotropic-like rather than ionotropic activation of the α7 receptor subtype in non-neuronal cells. We previously identified para-trifluoromethyl (p-CF3) N,N-diethyl-N'-phenylpiperazinium (diEPP) iodide to be among the compounds classified as silent agonists, which are very weak α7 partial agonists that are able to induce positive allosteric modulator (PAM)-sensitive desensitization. Such drugs have been shown to selectively promote α7 ionotropic-independent functions. Therefore, we here further investigated the electrophysiological profile of p-CF3 diEPP and its in vivo antinociceptive activity using Xenopus oocytes expressing α7, α4β2, or α3β4 nAChRs. The evoked currents confirmed p-CF3 diEPP to be α7-selective with a maximal agonism 5% that of acetylcholine (ACh). Coapplication of p-CF3 diEPP with the type II PAM 4-naphthalene-1-yl-3a,4,5,9b-tetrahydro-3-H-cyclopenta[c]quinoline-8-sulfonic acid amide (TQS) produced desensitization that could be converted to PAM-potentiated currents, which at a negative holding potential were up to 13-fold greater than ACh controls. Voltage-dependence experiments indicated that channel block may limit both control ACh and TQS-potentiated responses. Although no p-CF3 diEPP agonist activity was detected for the heteromeric nAChRs, it was a noncompetitive antagonist of these receptors. The compound displayed remarkable antihyperalgesic and antiedema effects in in vivo assays. The antinociceptive activity was dose and time dependent. The anti-inflammatory components were sensitive to the α7-selective antagonist methyllycaconitine, which supports the idea that these effects are mediated by the α7 nAChR.
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Affiliation(s)
- Marta Quadri
- Departments of Pharmacology and Therapeutics (M.Q., C.S., R.L.P.) and Chemistry (M.Q., N.A.H.), University of Florida, Gainesville, Florida; and Department of Pharmacology and Toxicology, Medical College of Virginia, Virginia Commonwealth University, Richmond, Virginia (D.B., W.T., M.I.D.)
| | - Deniz Bagdas
- Departments of Pharmacology and Therapeutics (M.Q., C.S., R.L.P.) and Chemistry (M.Q., N.A.H.), University of Florida, Gainesville, Florida; and Department of Pharmacology and Toxicology, Medical College of Virginia, Virginia Commonwealth University, Richmond, Virginia (D.B., W.T., M.I.D.)
| | - Wisam Toma
- Departments of Pharmacology and Therapeutics (M.Q., C.S., R.L.P.) and Chemistry (M.Q., N.A.H.), University of Florida, Gainesville, Florida; and Department of Pharmacology and Toxicology, Medical College of Virginia, Virginia Commonwealth University, Richmond, Virginia (D.B., W.T., M.I.D.)
| | - Clare Stokes
- Departments of Pharmacology and Therapeutics (M.Q., C.S., R.L.P.) and Chemistry (M.Q., N.A.H.), University of Florida, Gainesville, Florida; and Department of Pharmacology and Toxicology, Medical College of Virginia, Virginia Commonwealth University, Richmond, Virginia (D.B., W.T., M.I.D.)
| | - Nicole A Horenstein
- Departments of Pharmacology and Therapeutics (M.Q., C.S., R.L.P.) and Chemistry (M.Q., N.A.H.), University of Florida, Gainesville, Florida; and Department of Pharmacology and Toxicology, Medical College of Virginia, Virginia Commonwealth University, Richmond, Virginia (D.B., W.T., M.I.D.)
| | - M Imad Damaj
- Departments of Pharmacology and Therapeutics (M.Q., C.S., R.L.P.) and Chemistry (M.Q., N.A.H.), University of Florida, Gainesville, Florida; and Department of Pharmacology and Toxicology, Medical College of Virginia, Virginia Commonwealth University, Richmond, Virginia (D.B., W.T., M.I.D.)
| | - Roger L Papke
- Departments of Pharmacology and Therapeutics (M.Q., C.S., R.L.P.) and Chemistry (M.Q., N.A.H.), University of Florida, Gainesville, Florida; and Department of Pharmacology and Toxicology, Medical College of Virginia, Virginia Commonwealth University, Richmond, Virginia (D.B., W.T., M.I.D.)
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19
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King JR, Ullah A, Bak E, Jafri MS, Kabbani N. Ionotropic and Metabotropic Mechanisms of Allosteric Modulation of α7 Nicotinic Receptor Intracellular Calcium. Mol Pharmacol 2018; 93:601-611. [PMID: 29588343 PMCID: PMC11033947 DOI: 10.1124/mol.117.111401] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Accepted: 03/23/2018] [Indexed: 12/13/2022] Open
Abstract
The pharmacological targeting of the α7 nicotinic acetylcholine receptor (α7) is a promising strategy in the development of new drugs for neurologic diseases. Because α7 receptors regulate cellular calcium, we investigated how the prototypical type II-positive allosteric modulator PNU120596 affects α7-mediated calcium signaling. Live imaging experiments show that PNU120596 augments ryanodine receptor-driven calcium-induced calcium release (CICR), inositol-induced calcium release (IICR), and phospholipase C activation by the α7 receptor. Both influx of calcium through the α7 nicotinic acetylcholine receptor (nAChR) channel as well as the binding of intracellular G proteins were involved in the effect of PNU120596 on intracellular calcium. This is evidenced by the findings that chelation of extracellular calcium, expression of α7D44A or α7345-348A mutant subunits, or blockade of calcium store release compromised the ability of PNU120596 to increase intracellular calcium transients generated by α7 ligand activation. Spatiotemporal stochastic modeling of calcium transient responses corroborates these results and indicates that α7 receptor activation enables calcium microdomains locally and to lesser extent in the distant cytosol. From the model, allosteric modulation of the receptor activates CICR locally via ryanodine receptors and augments IICR through enhanced calcium influx due to prolonged α7 nAChR opening. These findings provide a new mechanistic framework for understanding the effect of α7 receptor allosteric modulation on both local and global calcium dynamics.
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Affiliation(s)
- Justin R King
- Interdisciplinary Program in Neuroscience (J.R.K., M.S.J., N.K.) and School of Systems Biology (A.U., E.B., M.S.J., N.K.), George Mason University, Fairfax, Virginia
| | - Aman Ullah
- Interdisciplinary Program in Neuroscience (J.R.K., M.S.J., N.K.) and School of Systems Biology (A.U., E.B., M.S.J., N.K.), George Mason University, Fairfax, Virginia
| | - Ellen Bak
- Interdisciplinary Program in Neuroscience (J.R.K., M.S.J., N.K.) and School of Systems Biology (A.U., E.B., M.S.J., N.K.), George Mason University, Fairfax, Virginia
| | - M Saleet Jafri
- Interdisciplinary Program in Neuroscience (J.R.K., M.S.J., N.K.) and School of Systems Biology (A.U., E.B., M.S.J., N.K.), George Mason University, Fairfax, Virginia
| | - Nadine Kabbani
- Interdisciplinary Program in Neuroscience (J.R.K., M.S.J., N.K.) and School of Systems Biology (A.U., E.B., M.S.J., N.K.), George Mason University, Fairfax, Virginia
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20
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Bouzat C, Sine SM. Nicotinic acetylcholine receptors at the single-channel level. Br J Pharmacol 2018; 175:1789-1804. [PMID: 28261794 PMCID: PMC5979820 DOI: 10.1111/bph.13770] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Revised: 02/21/2017] [Accepted: 02/24/2017] [Indexed: 01/28/2023] Open
Abstract
Over the past four decades, the patch clamp technique and nicotinic ACh (nACh) receptors have established an enduring partnership. Like all good partnerships, each partner has proven significant in its own right, while their union has spurred innumerable advances in life science research. A member and prototype of the superfamily of pentameric ligand-gated ion channels, the nACh receptor is a chemo-electric transducer, binding ACh released from nerves and rapidly opening its channel to cation flow to elicit cellular excitation. A subject of a Nobel Prize in Physiology or Medicine, the patch clamp technique provides unprecedented resolution of currents through single ion channels in their native cellular environments. Here, focusing on muscle and α7 nACh receptors, we describe the extraordinary contribution of the patch clamp technique towards understanding how they activate in response to neurotransmitter, how subtle structural and mechanistic differences among nACh receptor subtypes translate into significant physiological differences, and how nACh receptors are being exploited as therapeutic drug targets. LINKED ARTICLES This article is part of a themed section on Nicotinic Acetylcholine Receptors. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v175.11/issuetoc/.
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Affiliation(s)
- Cecilia Bouzat
- Instituto de Investigaciones Bioquímicas de Bahía Blanca, INIBIBB (CONICET‐UNS), Departamento de Biología, Bioquímica y FarmaciaUniversidad Nacional del SurBahía BlancaArgentina
| | - Steven M Sine
- Receptor Biology Laboratory, Department of Physiology and Biomedical EngineeringMayo Clinic College of MedicineRochesterMN55905USA
- Department of NeurologyMayo Clinic College of MedicineRochesterMN55905USA
- Department of Pharmacology and Experimental TherapeuticsMayo Clinic College of MedicineRochesterMN55905USA
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21
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Li Y, Sun L, Yang T, Jiao W, Tang J, Huang X, Huang Z, Meng Y, Luo L, Wang X, Bian X, Zhang F, Wang K, Sun Q. Design and Synthesis of Novel Positive Allosteric Modulators of α7 Nicotinic Acetylcholine Receptors with the Ability To Rescue Auditory Gating Deficit in Mice. J Med Chem 2018; 62:159-173. [DOI: 10.1021/acs.jmedchem.7b01492] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Yuanheng Li
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing 100191, China
| | - Lilan Sun
- Department of Pharmacology, School of Pharmacy, Qingdao University, Qingdao 266021, China
| | - Taoyi Yang
- Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University, Beijing 100191, China
| | - Wenxuan Jiao
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing 100191, China
| | - Jingshu Tang
- Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University, Beijing 100191, China
| | - Xiaomin Huang
- Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University, Beijing 100191, China
| | - Zongze Huang
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing 100191, China
| | - Ying Meng
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing 100191, China
| | - Laichun Luo
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing 100191, China
| | - Xintong Wang
- Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University, Beijing 100191, China
| | - Xiling Bian
- Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University, Beijing 100191, China
| | - Fang Zhang
- Department of Pharmacology, School of Pharmacy, Qingdao University, Qingdao 266021, China
| | - KeWei Wang
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing 100191, China
- Department of Pharmacology, School of Pharmacy, Qingdao University, Qingdao 266021, China
- Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University, Beijing 100191, China
| | - Qi Sun
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing 100191, China
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22
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Capó-Vélez CM, Morales-Vargas B, García-González A, Grajales-Reyes JG, Delgado-Vélez M, Madera B, Báez-Pagán CA, Quesada O, Lasalde-Dominicci JA. The alpha7-nicotinic receptor contributes to gp120-induced neurotoxicity: implications in HIV-associated neurocognitive disorders. Sci Rep 2018; 8:1829. [PMID: 29379089 PMCID: PMC5788855 DOI: 10.1038/s41598-018-20271-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2017] [Accepted: 01/15/2018] [Indexed: 01/14/2023] Open
Abstract
Currently, there are no specific therapies to treat HIV-1 associated neurocognitive disorders (HAND). The HIV-1 envelope, gp120, induces neuropathological changes similar to those in HAND patients; furthermore, it triggers an upregulation of the α7-nicotinic acetylcholine receptor (α7-nAChR), facilitating intracellular calcium overload and neuronal cell death. Using a gp120IIIB-transgenic mouse (gp120-tgm) model, we demonstrate that α7-nAChRs are upregulated on striatal neurons. Activation of α7-nAChRs leads to an increase in both intracellular calcium and percentage of apoptotic cells, which can be abrogated by antagonizing the receptor, suggesting a role for α7-nAChRs in gp120-induced neurotoxicity. Moreover, we demonstrate for the first time that gp120-tgm have learning deficiencies on a striatum-dependent behavioral task. They also show locomotor deficiencies, which improved with α7-nAChR antagonists, further supporting a role for this receptor in gp120-induced neurotoxicity. Together, these results uncover a new mechanism through which gp120-induced modulation of α7-nAChRs in the striatum can contribute to HAND development.
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Affiliation(s)
- Coral M Capó-Vélez
- University of Puerto Rico, Río Piedras Campus, Department of Biology, San Juan, P.R, 00931-3360, Puerto Rico.,University of Puerto Rico, Molecular Sciences and Research Center, San Juan, P.R, 00926, Puerto Rico
| | - Bryan Morales-Vargas
- University of Puerto Rico, Río Piedras Campus, Department of Biology, San Juan, P.R, 00931-3360, Puerto Rico
| | - Aurian García-González
- University of Puerto Rico, Río Piedras Campus, Department of Biology, San Juan, P.R, 00931-3360, Puerto Rico
| | - José G Grajales-Reyes
- University of Puerto Rico, Río Piedras Campus, Department of Biology, San Juan, P.R, 00931-3360, Puerto Rico
| | - Manuel Delgado-Vélez
- University of Puerto Rico, Río Piedras Campus, Department of Biology, San Juan, P.R, 00931-3360, Puerto Rico.,University of Puerto Rico, Molecular Sciences and Research Center, San Juan, P.R, 00926, Puerto Rico
| | - Bismark Madera
- University of Puerto Rico, Río Piedras Campus, Department of Biology, San Juan, P.R, 00931-3360, Puerto Rico.,University of Puerto Rico, Molecular Sciences and Research Center, San Juan, P.R, 00926, Puerto Rico
| | - Carlos A Báez-Pagán
- University of Puerto Rico, Río Piedras Campus, Department of Physical Sciences, San Juan, P.R, 00931-3360, Puerto Rico
| | - Orestes Quesada
- University of Puerto Rico, Río Piedras Campus, Department of Physical Sciences, San Juan, P.R, 00931-3360, Puerto Rico
| | - José A Lasalde-Dominicci
- University of Puerto Rico, Río Piedras Campus, Department of Biology, San Juan, P.R, 00931-3360, Puerto Rico. .,University of Puerto Rico, Río Piedras Campus, Department of Chemistry, San Juan, P.R, 00931-3360, Puerto Rico. .,University of Puerto Rico, Molecular Sciences and Research Center, San Juan, P.R, 00926, Puerto Rico.
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23
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Happ DF, Tasker RA. Effects of α7 Nicotinic Receptor Activation on Cell Survival in Rat Organotypic Hippocampal Slice Cultures. Neurotox Res 2017; 33:887-895. [DOI: 10.1007/s12640-017-9854-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Revised: 12/04/2017] [Accepted: 12/13/2017] [Indexed: 11/28/2022]
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24
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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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25
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Liu HX, Liu S, Qu W, Yan HY, Wen X, Chen T, Hou LF, Ping J. α7 nAChR mediated Fas demethylation contributes to prenatal nicotine exposure-induced programmed thymocyte apoptosis in mice. Oncotarget 2017; 8:93741-93756. [PMID: 29212186 PMCID: PMC5706832 DOI: 10.18632/oncotarget.21526] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Accepted: 09/20/2017] [Indexed: 01/19/2023] Open
Abstract
This study aimed to investigate the effects of prenatal nicotine exposure (PNE) on thymocyte apoptosis and postnatal immune impairments in vivo and further explore the epigenetic mechanisms of the pro-apoptotic effect of nicotine in vitro. The results showed that PNE caused immune impairments in offspring on postnatal day 49, manifested as increased IL-4 production and an increased IgG1/IgG2a ratio in serum. Enhanced apoptosis of total and CD4+SP thymocytes was observed both in fetus and in offspring. Further, by exposing thymocytes to 0–100 μM of nicotine in vitro for 48 h, we found that nicotine increased α7 nicotinic acetylcholine receptor (nAChR) expression, activated the Fas apoptotic pathway, and promoted thymocyte apoptosis in concentration-dependent manners. In addition, nicotine could induce Tet methylcytosine dioxygenase (TET) 2 expression and Fas promoter demethylation, which can be abolished by TET2 siRNA transfection. Moreover, the α7 nAChR specific antagonist α-bungarotoxin can abrogate nicotine-induced TET2 increase, and the following Fas demethylation and Fas-mediated apoptosis. In conclusion, our findings showed, for the first time, that α7 nAChR activation could induce TET2-mediated Fas demethylation in thymocytes and results in the upregulation of Fas apoptotic pathway, which provide evidence for elucidating the PNE-induced programmed thymocyte apoptosis.
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Affiliation(s)
- Han-Xiao Liu
- Department of Pharmacology, Wuhan University School of Basic Medical Sciences, Wuhan 430071, China
| | - Sha Liu
- Department of Pharmacology, Wuhan University School of Basic Medical Sciences, Wuhan 430071, China
| | - Wen Qu
- Department of Pharmacology, Wuhan University School of Basic Medical Sciences, Wuhan 430071, China
| | - Hui-Yi Yan
- Department of Pharmacology, Wuhan University School of Basic Medical Sciences, Wuhan 430071, China
| | - Xiao Wen
- Department of Pharmacology, Wuhan University School of Basic Medical Sciences, Wuhan 430071, China
| | - Ting Chen
- Department of Pharmacology, Wuhan University School of Basic Medical Sciences, Wuhan 430071, China
| | - Li-Fang Hou
- Department of Pharmacology, Wuhan University School of Basic Medical Sciences, Wuhan 430071, China
| | - Jie Ping
- Department of Pharmacology, Wuhan University School of Basic Medical Sciences, Wuhan 430071, China
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26
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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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27
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Beart PM. Synaptic signalling and its interface with neuropathologies: snapshots from the past, present and future. J Neurochem 2016; 139 Suppl 2:76-90. [PMID: 27144305 DOI: 10.1111/jnc.13598] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2015] [Revised: 02/09/2016] [Accepted: 02/26/2016] [Indexed: 11/30/2022]
Abstract
This 'Past to Future' Review as part of the 60th anniversary year of the Journal of Neurochemistry focuses on synaptic transmission and associated signalling, and seeks to identify seminal progress in neurochemistry over the last 10 years which has advanced our understanding of neuronal communication in brain. The approach adopted analyses neurotransmitters on a case by case basis (i.e. amino acids, monoamines, acetylcholine, neuropeptides, ATP/purines and gasotransmitters) to highlight novel findings that have changed the way we view each type of transmitter, to explore commonalities and interactions, and to note how new insights have changed the way we view the biology of degenerative, psychiatric and behavioural conditions. Across all transmitter systems there was remarkable growth in the identification of targets likely to provide therapeutic benefit and which undoubtedly was driven by the elucidation of circuit function and new vistas of synaptic signalling. There has been an increasing trend to relate signalling to disease, notably for Alzheimer's and Parkinson's disease and related conditions, and which has occurred for each transmitter family. Forebrain circuitry and tonic excitatory control have been the centre of great attention yielding novel findings that will impact upon cognitive, emotional and addictive behaviours. Other impressive insights focus on gasotransmitters integrating activity as volume transmitters. Exciting developments in how serotonin, cholinergic, l-glutamate, galanin and adenosine receptors and their associated signalling can be beneficially targeted should underpin the development of new therapies. Clearly integrated, multifaceted neurochemistry has changed the way we view synaptic signalling and its relevance to pathobiology. Highlighted are important advances in synaptic signalling over the last decade in the Journal of Neurochemistry. Across all transmitter systems elucidation of circuit function, and notably molecular insights, have underpinned remarkable growth in the identification of targets likely to provide therapeutic benefit in neuropathologies. Another commonality was wide interest in forebrain circuitry and its tonic excitatory control. Increasingly observations relate to signalling in disease and behavioural conditions. This article is part of the 60th Anniversary special issue.
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Affiliation(s)
- Philip M Beart
- Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria, Australia.
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28
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Andersen ND, Nielsen BE, Corradi J, Tolosa MF, Feuerbach D, Arias HR, Bouzat C. Exploring the positive allosteric modulation of human α7 nicotinic receptors from a single-channel perspective. Neuropharmacology 2016; 107:189-200. [PMID: 26926428 DOI: 10.1016/j.neuropharm.2016.02.032] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Revised: 01/20/2016] [Accepted: 02/24/2016] [Indexed: 12/30/2022]
Abstract
Enhancement of α7 nicotinic receptor (nAChR) function by positive allosteric modulators (PAMs) is a promising therapeutic strategy to improve cognitive deficits. PAMs have been classified only on the basis of their macroscopic effects as type I, which only enhance agonist-induced currents, and type II, which also decrease desensitization and reactivate desensitized nAChRs. To decipher the molecular basis underlying these distinct activities, we explored the effects on single-α7 channel currents of representative members of each type and of less characterized compounds. Our results reveal that all PAMs enhance open-channel lifetime and produce episodes of successive openings, thus indicating that both types affect α7 kinetics. Different PAM types show different sensitivity to temperature, suggesting different mechanisms of potentiation. By using a mutant α7 receptor that is insensitive to the prototype type II PAM (PNU-120596), we show that some though not all type I PAMs share the structural determinants of potentiation. Overall, our study provides novel information on α7 potentiation, which is key to the ongoing development of therapeutic compounds.
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Affiliation(s)
- Natalia D Andersen
- Universidad Nacional del Sur/CONICET, Instituto de Investigaciones Bioquímicas de Bahía Blanca, Bahía Blanca 8000, Argentina
| | - Beatriz E Nielsen
- Universidad Nacional del Sur/CONICET, Instituto de Investigaciones Bioquímicas de Bahía Blanca, Bahía Blanca 8000, Argentina
| | - Jeremías Corradi
- Universidad Nacional del Sur/CONICET, Instituto de Investigaciones Bioquímicas de Bahía Blanca, Bahía Blanca 8000, Argentina
| | - María F Tolosa
- Universidad Nacional del Sur/CONICET, Instituto de Investigaciones Bioquímicas de Bahía Blanca, Bahía Blanca 8000, Argentina
| | - Dominik Feuerbach
- Neuroscience Research, Novartis Institutes for Biomedical Research, Basel, Switzerland
| | - Hugo R Arias
- Department of Medical Education, California Northstate University College of Medicine, Elk Grove, CA 95757, USA
| | - Cecilia Bouzat
- Universidad Nacional del Sur/CONICET, Instituto de Investigaciones Bioquímicas de Bahía Blanca, Bahía Blanca 8000, Argentina.
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29
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Sun F, Johnson SR, Jin K, Uteshev VV. Boosting Endogenous Resistance of Brain to Ischemia. Mol Neurobiol 2016; 54:2045-2059. [PMID: 26910820 DOI: 10.1007/s12035-016-9796-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2015] [Accepted: 02/16/2016] [Indexed: 12/22/2022]
Abstract
Most survivors of ischemic stroke remain physically disabled and require prolonged rehabilitation. However, some stroke victims achieve a full neurological recovery suggesting that the human brain can defend itself against ischemic injury, but the protective mechanisms are unknown. This study used selective pharmacological agents and a rat model of cerebral ischemic stroke to detect endogenous brain protective mechanisms that require activation of α7 nicotinic acetylcholine receptors (nAChRs). This endogenous protection was found to be (1) limited to less severe injuries; (2) significantly augmented by intranasal administration of a positive allosteric modulator of α7 nAChRs, significantly reducing brain injury and neurological deficits after more severe ischemic injuries; and (3) reduced by inhibition of calcium/calmodulin-dependent kinase-II. The physiological role of α7 nAChRs remains largely unknown. The therapeutic activation of α7 nAChRs after cerebral ischemia may serve as an important physiological responsibility of these ubiquitous receptors and holds a significant translational potential.
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Affiliation(s)
- Fen Sun
- Institute for Healthy Aging, Center for Neuroscience Discovery, University of North Texas Health Science Center, 3500 Camp Bowie Blvd., Fort Worth, TX, 76107, USA
| | | | - Kunlin Jin
- Institute for Healthy Aging, Center for Neuroscience Discovery, University of North Texas Health Science Center, 3500 Camp Bowie Blvd., Fort Worth, TX, 76107, USA
| | - Victor V Uteshev
- Institute for Healthy Aging, Center for Neuroscience Discovery, University of North Texas Health Science Center, 3500 Camp Bowie Blvd., Fort Worth, TX, 76107, USA.
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30
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Anti-inflammatory role of microglial alpha7 nAChRs and its role in neuroprotection. Biochem Pharmacol 2015; 97:463-472. [DOI: 10.1016/j.bcp.2015.07.032] [Citation(s) in RCA: 213] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Accepted: 07/27/2015] [Indexed: 12/15/2022]
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31
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Shin SS, Dixon CE. Targeting α7 nicotinic acetylcholine receptors: a future potential for neuroprotection from traumatic brain injury. Neural Regen Res 2015; 10:1552-4. [PMID: 26692836 PMCID: PMC4660732 DOI: 10.4103/1673-5374.165309] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/15/2015] [Indexed: 12/13/2022] Open
Affiliation(s)
- Samuel S. Shin
- Department of Neurological Surgery, University of Pittsburgh Medical Center, Pittsburgh, PA, USA
| | - C. Edward Dixon
- Department of Neurological Surgery, University of Pittsburgh Medical Center, Pittsburgh, PA, USA
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32
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Uteshev V. Are positive allosteric modulators of α7 nAChRs clinically safe? J Neurochem 2015; 136:217-9. [PMID: 26182952 DOI: 10.1111/jnc.13236] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 07/02/2015] [Indexed: 12/12/2022]
Affiliation(s)
- Victor Uteshev
- Department of Pharmacology & Neuroscience, Institute of Aging and Alzheimer's Disease Research, University of North Texas Health Science Center, Fort Worth, Texas, USA
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33
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King JR, Nordman JC, Bridges SP, Lin MK, Kabbani N. Identification and Characterization of a G Protein-binding Cluster in α7 Nicotinic Acetylcholine Receptors. J Biol Chem 2015; 290:20060-70. [PMID: 26088141 DOI: 10.1074/jbc.m115.647040] [Citation(s) in RCA: 83] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Indexed: 12/14/2022] Open
Abstract
α7 nicotinic acetylcholine receptors (nAChRs) play an important role in synaptic transmission and inflammation. In response to ligands, this receptor channel opens to conduct cations into the cell but desensitizes rapidly. In recent studies we show that α7 nAChRs bind signaling proteins such as heterotrimeric GTP-binding proteins (G proteins). Here, we demonstrate that direct coupling of α7 nAChRs to G proteins enables a downstream calcium signaling response that can persist beyond the expected time course of channel activation. This process depends on a G protein-binding cluster (GPBC) in the M3-M4 loop of the receptor. A mutation of the GPBC in the α7 nAChR (α7345-348A) abolishes interaction with Gαq as well as Gβγ while having no effect on receptor synthesis, cell-surface trafficking, or α-bungarotoxin binding. Expression of α7345-348A, however, did significantly attenuate the α7 nAChR-induced Gαq calcium signaling response as evidenced by a decrease in PLC-β activation and IP3R-mediated calcium store release in the presence of the α7 selective agonist choline. Taken together, the data provides new evidence for the existence of a GPBC in nAChRs serving to promote intracellular signaling.
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Affiliation(s)
- Justin R King
- From the Department of Molecular Neuroscience, Krasnow Institute for Advanced Study and Department of Computer Science, George Mason University, Fairfax, Virginia 22030 and the INOVA Neuroscience Program, Annandale, Virginia 22003
| | - Jacob C Nordman
- From the Department of Molecular Neuroscience, Krasnow Institute for Advanced Study and Department of Computer Science, George Mason University, Fairfax, Virginia 22030 and the INOVA Neuroscience Program, Annandale, Virginia 22003
| | - Samuel P Bridges
- From the Department of Molecular Neuroscience, Krasnow Institute for Advanced Study and Department of Computer Science, George Mason University, Fairfax, Virginia 22030 and the INOVA Neuroscience Program, Annandale, Virginia 22003
| | - Ming-Kuan Lin
- From the Department of Molecular Neuroscience, Krasnow Institute for Advanced Study and Department of Computer Science, George Mason University, Fairfax, Virginia 22030 and the INOVA Neuroscience Program, Annandale, Virginia 22003
| | - Nadine Kabbani
- From the Department of Molecular Neuroscience, Krasnow Institute for Advanced Study and Department of Computer Science, George Mason University, Fairfax, Virginia 22030 and the INOVA Neuroscience Program, Annandale, Virginia 22003
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