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Gok M, Madrer N, Zorbaz T, Bennett ER, Greenberg D, Bennett DA, Soreq H. Altered levels of variant cholinesterase transcripts contribute to the imbalanced cholinergic signaling in Alzheimer's and Parkinson's disease. Front Mol Neurosci 2022; 15:941467. [PMID: 36117917 PMCID: PMC9479005 DOI: 10.3389/fnmol.2022.941467] [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: 05/11/2022] [Accepted: 08/03/2022] [Indexed: 11/13/2022] Open
Abstract
Acetylcholinesterase and butyrylcholinesterase (AChE and BChE) are involved in modulating cholinergic signaling, but their roles in Alzheimer's and Parkinson's diseases (AD and PD) remain unclear. We identified a higher frequency of the functionally impaired BCHE-K variant (rs1803274) in AD and PD compared to controls and lower than in the GTEx dataset of healthy individuals (n = 651); in comparison, the prevalence of the 5'-UTR (rs1126680) and intron 2 (rs55781031) single-nucleotide polymorphisms (SNPs) of BCHE and ACHE's 3'-UTR (rs17228616) which disrupt AChE mRNA targeting by miR-608 remained unchanged. qPCR validations confirmed lower levels of the dominant splice variant encoding the "synaptic" membrane-bound ACHE-S in human post-mortem superior temporal gyrus samples from AD and in substantia nigra (but not amygdala) samples from PD patients (n = 79, n = 67) compared to controls, potentially reflecting region-specific loss of cholinergic neurons. In contradistinction, the non-dominant "readthrough" AChE-R mRNA variant encoding for soluble AChE was elevated (p < 0.05) in the AD superior temporal gyrus and the PD amygdala, but not in the neuron-deprived substantia nigra. Elevated levels of BChE (p < 0.001) were seen in AD superior temporal gyrus. Finally, all three ACHE splice variants, AChE-S, AChE-R, and N-extended AChE, were elevated in cholinergic-differentiated human neuroblastoma cells, with exposure to the oxidative stress agent paraquat strongly downregulating AChE-S and BChE, inverse to their upregulation under exposure to the antioxidant simvastatin. The multi-leveled changes in cholinesterase balance highlight the role of post-transcriptional regulation in neurodegeneration. (235).
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Affiliation(s)
- Muslum Gok
- Department of Biochemistry, Faculty of Medicine, Muğla Sıtkı Koçman University, Muğla, Turkey
- Edmond and Lily Safra Center for Brain Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Nimrod Madrer
- Edmond and Lily Safra Center for Brain Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
- Department of Biological Chemistry, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Tamara Zorbaz
- Edmond and Lily Safra Center for Brain Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
- Biochemistry and Organic Analytical Chemistry Unit, Institute for Medical Research and Occupational Health, Zagreb, Croatia
| | - Estelle R. Bennett
- Edmond and Lily Safra Center for Brain Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
- Department of Biological Chemistry, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - David Greenberg
- Edmond and Lily Safra Center for Brain Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
- Department of Biological Chemistry, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - David A. Bennett
- Department of Neurological Sciences, Rush University Medical Center, Chicago, IL, United States
| | - Hermona Soreq
- Edmond and Lily Safra Center for Brain Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
- Department of Biological Chemistry, The Hebrew University of Jerusalem, Jerusalem, Israel
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TDP-43 Regulation of AChE Expression Can Mediate ALS-Like Phenotype in Zebrafish. Cells 2021; 10:cells10020221. [PMID: 33499374 PMCID: PMC7911940 DOI: 10.3390/cells10020221] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 01/13/2021] [Accepted: 01/13/2021] [Indexed: 12/12/2022] Open
Abstract
The "distal axonopathy" hypothesis in amyotrophic lateral sclerosis (ALS) proposes that pathological changes occur at the neuromuscular junction (NMJ) early in the disease. While acetylcholinesterase (AChE) plays an important role in the functionality of the NMJ, its potential role in ALS remains unexplored. Here, we identified AChE as a limiting factor regulating muscle/motor neuron connection in a vertebrate model of ALS. Knockdown of the TAR DNA-binding protein 43 (TDP-43) orthologue in zebrafish resulted in early defects of motor functions coupled with NMJ disassembly. We found that a partially depleted tdp-43 caused a decrease of ache expression. Importantly, human AChE overexpression reduced the phenotypic defects in the tdp-43 loss of function model, with amelioration of post- and pre-synaptic deficits at the NMJ. In conclusion, our results provide a better understanding of the role of TDP-43 in the NMJ organization and indicate AChE as a contributing factor in the pathology of ALS. In particular, it may be implicated in the early defects that characterize NMJs in this major neurodegenerative disorder.
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The multiple biological roles of the cholinesterases. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2020; 162:41-56. [PMID: 33307019 DOI: 10.1016/j.pbiomolbio.2020.12.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 11/30/2020] [Accepted: 12/03/2020] [Indexed: 12/14/2022]
Abstract
It is tacitly assumed that the biological role of acetylcholinesterase is termination of synaptic transmission at cholinergic synapses. However, together with its structural homolog, butyrylcholinesterase, it is widely distributed both within and outside the nervous system, and, in many cases, the role of both enzymes remains obscure. The transient appearance of the cholinesterases in embryonic tissues is especially enigmatic. The two enzymes' extra-synaptic roles, which are known as 'non-classical' roles, are the topic of this review. Strong evidence has been presented that AChE and BChE play morphogenetic roles in a variety of eukaryotic systems, and they do so either by acting as adhesion proteins, or as trophic factors. As trophic factors, one mode of action is to directly regulate morphogenesis, such as neurite outgrowth, by poorly understood mechanisms. The other mode is by regulating levels of acetylcholine, which acts as the direct trophic factor. Alternate substrates have been sought for the cholinesterases. Quite recently, it was shown that levels of the aggression hormone, ghrelin, which also controls appetite, are regulated by butyrylcholinesterase. The rapid hydrolysis of acetylcholine by acetylcholinesterase generates high local proton concentrations. The possible biophysical and biological consequences of this effect are discussed. The biological significance of the acetylcholinesterases secreted by parasitic nematodes is reviewed, and, finally, the involvement of acetylcholinesterase in apoptosis is considered.
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Characterization of the rat Acetylcholinesterase readthrough (AChE-R) splice variant: Implications for toxicological studies. Biochem Biophys Res Commun 2020; 532:528-534. [PMID: 32896378 DOI: 10.1016/j.bbrc.2020.08.065] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Accepted: 08/21/2020] [Indexed: 11/23/2022]
Abstract
Exposure to chemicals and other environmental stressors can differentially impact the expression of Acetylcholinesterase (AChE) splice variants. Surprisingly, despite the widespread use of the rat model in toxicological studies and the wealth of literature on this important biomarker of neurotoxicity, AChE coding exons and splice variants are not yet fully annotated in this species. To address this knowledge gap, a short problematic region of the rat AChE genomic DNA present in GenBank was first re-sequenced. This revised genomic sequence was then aligned to rat AChE RefSeq mRNA and compared to orthologous mammalian sequences, in order to map the coding exon and intron boundaries of the rat AChE gene. Based on these bioinformatics analyses, a sequence was predicted for the yet-unannotated rat Acetylcholinesterase readthrough (AChE-R) splice variant. PCR primers designed to specifically amplify rat AChE-R were used to confirm its expression in rat PC12 cells. Compared to the canonical AChE-S splice variant, AChE-R was expressed at much lower levels but presented distinct regulation patterns in PC12 cells and rat primary cerebral granule cells (CGCs) following exposure to Chlorpyrifos (a well-known neurotoxic organophosphate pesticide). Taken together, these observations point to the evolutionary conservation of the AChE-R splicing event between rodents and human and to the distinct regulation of AChE splice variants in response to toxicological challenges.
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Restored presynaptic synaptophysin and cholinergic inputs contribute to the protective effects of physical running on spatial memory in aged mice. Neurobiol Dis 2019; 132:104586. [DOI: 10.1016/j.nbd.2019.104586] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2019] [Revised: 08/06/2019] [Accepted: 08/23/2019] [Indexed: 01/16/2023] Open
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Abu Zeid EH, Alam RTM, Ali SA, Hendawi MY. Dose-related impacts of imidacloprid oral intoxication on brain and liver of rock pigeon (Columba livia domestica), residues analysis in different organs. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2019; 167:60-68. [PMID: 30296697 DOI: 10.1016/j.ecoenv.2018.09.121] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Revised: 09/26/2018] [Accepted: 09/28/2018] [Indexed: 05/21/2023]
Abstract
Available data regarding Imidacloprid (IMI) insecticide hazards to birds are still being scare. Our study aimed to investigate toxic impacts of IMI oral gavage by different dose levels on the brain and liver of Rock pigeon (Columba livia domestica). Forty mature male birds were divided equally into four groups. A control group (C) was orally dosed Mazola corn oil and other three groups; the low dose (LD), the medium dose (MD), and the high dose (HD) groups were orally dosed IMI in Mazola corn oil by three dose levels corresponding to 1/15th, 1/10th, 1/5th IMI oral LD50 respectively. IMI exposure induced a significant decrease in serum levels of glutathione (GSH), superoxide dismutase (SOD) enzyme activity. On the other hand; malondialdehyde (MDA) levels were elevated. The levels of serum total protein, albumin, globulin, and A/G ratio showed a non-significant changes in all IMI dosed groups except levels of total protein in the HD IMI dosed group showed a significant decrease compared to the C group. Serum levels of alanine aminotransferase (ALT), lactate dehydrogenase (LDH), uric acid, plasma tumor necrosis factor α (TNFα) and plasma acetylcholinesterase (AChEs) enzyme activities showed a significant dose related increase in all IMI exposed groups compared to the C group; except the levels of ALT, LDH, and uric acid showed a non significant decrease in the LD IMI dosed group only. Residues of IMI were detected in the pectoral muscles, liver, brain, and kidney of all dosed rock pigeon. Moreover; pectoral muscles were the highest tissue for IMI residues detection. This is the first study reports accumulation of IMI in tissues other than crop, liver, and kidney of rock pigeon including brain and muscles. Moreover, the examined brain and liver tissues of all IMI dosed groups showed dosed related alterations in their structural and ultra-structural morphology. It is concluded that IMI oral administration to pigeon induced oxidative stress and detrimental effects in brain and liver of exposed pigeons. Additionally; IMI bio-accumulated in different organs being muscles is the highest tissues for IMI residues, thus monitoring of IMI residues in food is very essential.
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Affiliation(s)
- Ehsan H Abu Zeid
- Department of Forensic Medicine and Toxicology, Faculty of Veterinary Medicine, Zagazig University, El-Sharkia Province, Egypt.
| | - Rasha T M Alam
- Department of Clinical Pathology, Faculty of Veterinary Medicine, Zagazig University, El-Sharkia Province, Egypt
| | - Sozan A Ali
- Department of Histology and Cytology, Faculty of Veterinary Medicine, Zagazig University, El-Sharkia Province, Egypt
| | - Mohamed Y Hendawi
- Department of Plant Protection, Faculty of Agriculture, Zagazig University, El-Sharkia Province, Egypt
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Assis CRD, Linhares AG, Cabrera MP, Oliveira VM, Silva KCC, Marcuschi M, Maciel Carvalho EVM, Bezerra RS, Carvalho LB. Erythrocyte acetylcholinesterase as biomarker of pesticide exposure: new and forgotten insights. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2018; 25:18364-18376. [PMID: 29797194 DOI: 10.1007/s11356-018-2303-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Accepted: 05/11/2018] [Indexed: 06/08/2023]
Abstract
Acetylcholinesterase (AChE) acts on the hydrolysis of acetylcholine, rapidly removing this neurotransmitter at cholinergic synapses and neuromuscular junctions as well as in neuronal growth and differentiation, modulation of cell adhesion ("electrotactins") and aryl-acylamidase activity (AAA). This enzyme is also found in erythrocyte, as 160 kDa dimer that anchors to the plasma membrane via glycophosphatidylinositol. The function of this enzyme in erythrocytes has not yet been elucidated; however, it is suspected to participate in cell-to-cell interactions. Here, a review on erythrocyte AChE characteristics and use as biomarker for organophosphorus and carbamate insecticides is presented since it is the first specific target/barrier of the action of these pesticides, besides plasma butyrylcholinesterase (BChE). However, some past and current methods have disadvantages: (a) not discriminating the activities of AChE and BChE; (b) low accuracy due to interference of hemoglobin in whole blood samples. On the other hand, extraction methods of hemoglobin-free erythrocyte AChE allows: (a) the freezing and transporting of samples; (b) samples free of colorimetric interference; (c) data from only erythrocyte AChE activity; (d) erythrocyte AChE specific activity presents higher correlation with the central nervous system AChE than other peripheral ChEs; (e) slow spontaneous regeneration against anti-ChEs agents of AChE in comparison to BChE, thus increasing the chances of detecting such compounds following longer interval after exposure. As monitoring perspectives, hemoglobin-free methodologies may be promising alternatives to assess the degree of exposure since they are not influenced by this interfering agent.
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Affiliation(s)
- Caio R D Assis
- Laboratório de Enzimologia - LABENZ, Departamento de Bioquímica and Laboratório de Imunopatologia Keizo Asami - LIKA, Universidade Federal de Pernambuco, Recife, Pernambuco, 50670-901, Brazil.
| | - Amanda G Linhares
- Laboratório de Enzimologia - LABENZ, Departamento de Bioquímica and Laboratório de Imunopatologia Keizo Asami - LIKA, Universidade Federal de Pernambuco, Recife, Pernambuco, 50670-901, Brazil
| | - Mariana P Cabrera
- Laboratório de Enzimologia - LABENZ, Departamento de Bioquímica and Laboratório de Imunopatologia Keizo Asami - LIKA, Universidade Federal de Pernambuco, Recife, Pernambuco, 50670-901, Brazil
| | - Vagne M Oliveira
- Laboratório de Tecnologia de Produtos Bioativos, Departamento de Morfologia e Fisiologia Animal, DMFA, Universidade Federal Rural de Pernambuco, Recife, Pernambuco, Brazil
| | - Kaline C C Silva
- Laboratório de Enzimologia - LABENZ, Departamento de Bioquímica and Laboratório de Imunopatologia Keizo Asami - LIKA, Universidade Federal de Pernambuco, Recife, Pernambuco, 50670-901, Brazil
- Universidade Estadual da Bahia, Paulo Afonso, Bahia, Brazil
| | - Marina Marcuschi
- Laboratório de Enzimologia - LABENZ, Departamento de Bioquímica and Laboratório de Imunopatologia Keizo Asami - LIKA, Universidade Federal de Pernambuco, Recife, Pernambuco, 50670-901, Brazil
| | - Elba V M Maciel Carvalho
- Laboratório de Glicoproteínas, Departamento de Bioquímica, Universidade Federal de Pernambuco, Recife, PE, Brazil
| | - Ranilson S Bezerra
- Laboratório de Enzimologia - LABENZ, Departamento de Bioquímica and Laboratório de Imunopatologia Keizo Asami - LIKA, Universidade Federal de Pernambuco, Recife, Pernambuco, 50670-901, Brazil
| | - Luiz B Carvalho
- Laboratório de Enzimologia - LABENZ, Departamento de Bioquímica and Laboratório de Imunopatologia Keizo Asami - LIKA, Universidade Federal de Pernambuco, Recife, Pernambuco, 50670-901, Brazil
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8
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Campanari ML, Navarrete F, Ginsberg SD, Manzanares J, Sáez-Valero J, García-Ayllón MS. Increased Expression of Readthrough Acetylcholinesterase Variants in the Brains of Alzheimer's Disease Patients. J Alzheimers Dis 2018; 53:831-41. [PMID: 27258420 DOI: 10.3233/jad-160220] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Alzheimer's disease (AD) is characterized by a decrease in the enzymatic activity of the enzyme acetylcholinesterase (AChE). AChE is expressed as multiple splice variants, which may serve both cholinergic degradative functions and non-cholinergic functions unrelated with their capacity to hydrolyze acetylcholine. We have recently demonstrated that a prominent pool of enzymatically inactive AChE protein exists in the AD brain. In this study, we analyzed protein and transcript levels of individual AChE variants in human frontal cortex from AD patients by western blot analysis using specific anti-AChE antibodies and by quantitative real-time PCR (qRT-PCR). We found similar protein and mRNA levels of the major cholinergic "tailed"-variant (AChE-T) and the anchoring subunit, proline-rich membrane anchor (PRiMA-1) in frontal cortex obtained from AD patients and non-demented controls. Interestingly, we found an increase in the protein and transcript levels of the non-cholinergic "readthrough" AChE (AChE-R) variants in AD patients compared to controls. Similar increases were detected by western blot using an antibody raised against the specific N-terminal domain, exclusive of alternative N-extended variants of AChE (N-AChE). In accordance with a subset of AChE-R monomers that display amphiphilic properties that are upregulated in the AD brain, we demonstrate that the increase of N-AChE species is due, at least in part, to N-AChE-R variants. In conclusion, we demonstrate selective alterations in specific AChE variants in AD cortex, with no correlation in enzymatic activity. Therefore, differential expression of AChE variants in AD may reflect changes in the pathophysiological role of AChE, independent of cholinergic impairment or its role in degrading acetylcholine.
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Affiliation(s)
- Maria-Letizia Campanari
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-CSIC, Sant Joan d'Alacant, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Spain
| | - Francisco Navarrete
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-CSIC, Sant Joan d'Alacant, Spain
| | - Stephen D Ginsberg
- Center for Dementia Research, Nathan Kline Institute, Departments of Psychiatry and Neuroscience & Physiology, New York University Langone Medical Center, Orangeburg, NY, USA
| | - Jorge Manzanares
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-CSIC, Sant Joan d'Alacant, Spain
| | - Javier Sáez-Valero
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-CSIC, Sant Joan d'Alacant, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Spain
| | - María-Salud García-Ayllón
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-CSIC, Sant Joan d'Alacant, Spain.,Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Spain.,Unidad de Investigación, Hospital General Universitario de Elche, FISABIO, Elche, Spain
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Meng X, Xu X, Bao H, Wang J, Liu Z. Characterization of the Fifth Putative Acetylcholinesterase in the Wolf Spider, Pardosa pseudoannulata. Molecules 2017; 22:E1118. [PMID: 28696352 PMCID: PMC6152279 DOI: 10.3390/molecules22071118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Revised: 06/29/2017] [Accepted: 07/01/2017] [Indexed: 11/17/2022] Open
Abstract
Background: Acetylcholinesterase (AChE) is an important neurotransmitter hydrolase in invertebrate and vertebrate nervous systems. The number of AChEs is various among invertebrate species, with different functions including the 'classical' role in terminating synaptic transmission and other 'non-classical' roles. Methods: Using rapid amplification of cDNA ends (RACE) technology, a new putative AChE-encoding gene was cloned from Pardosa pseudoannulata, an important predatory natural enemy. Sequence analysis and in vitro expression were employed to determine the structural features and biochemical properties of this putative AChE. Results: The cloned AChE contained the most conserved motifs of AChEs family and was clearly clustered with Arachnida AChEs. Determination of biochemical properties revealed that the recombinant enzyme had the obvious preference for the substrate ATC (acetylthiocholine iodide) versus BTC (butyrylthiocholine iodide). The AChE was highly sensitive to AChE-specific inhibitor BW284C51, but not butyrylcholinesterase-specific inhibitor tetraisopropyl pyrophosphoramide (ISO-OMPA). Based on these results, we concluded that a new AChE was identified from P. pseudoannulata and denoted as PpAChE5. Conclusion: Here we report the identification of a new AChE from P. pseudoannulata and increased the AChE number to five in this species. Although PpAChE5 had the biggest Vmax value among five identified AChEs, it showed relatively low affinity with ATC. Similar sensitivity to test insecticides indicated that this AChE might serve as the target for both organophosphorus and carbamate insecticides.
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Affiliation(s)
- Xiangkun Meng
- Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), College of Plant Protection, Nanjing Agricultural University, Weigang 1, Nanjing 210095, China.
- College of Horticulture and Plant Protection, Yangzhou University, Yangzhou 225009, China.
| | - Xixia Xu
- Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), College of Plant Protection, Nanjing Agricultural University, Weigang 1, Nanjing 210095, China.
| | - Haibo Bao
- Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), College of Plant Protection, Nanjing Agricultural University, Weigang 1, Nanjing 210095, China.
| | - Jianjun Wang
- College of Horticulture and Plant Protection, Yangzhou University, Yangzhou 225009, China.
| | - Zewen Liu
- Key Laboratory of Integrated Management of Crop Diseases and Pests (Ministry of Education), College of Plant Protection, Nanjing Agricultural University, Weigang 1, Nanjing 210095, China.
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High concentration of trichlorfon (1 mM) disrupts axonal cytoskeleton and decreases the expression of plasticity-related proteins in SH-SY5Y cells. Toxicol In Vitro 2017; 39:84-92. [DOI: 10.1016/j.tiv.2016.12.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Revised: 11/08/2016] [Accepted: 12/02/2016] [Indexed: 11/18/2022]
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Primary Investigation for the Mechanism of Biatractylolide from Atractylodis Macrocephalae Rhizoma as an Acetylcholinesterase Inhibitor. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2016; 2016:7481323. [PMID: 27642355 PMCID: PMC5013199 DOI: 10.1155/2016/7481323] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/29/2016] [Revised: 07/09/2016] [Accepted: 07/13/2016] [Indexed: 12/13/2022]
Abstract
Biatractylolide was isolated from ethyl acetate extract of dried Atractylodis Macrocephalae Rhizoma root by multistep chromatographic processing. Structure of biatractylolide was confirmed by (1)H-NMR and (13)C-NMR. The IC50 on acetylcholinesterase (AChE) activity was 6.5458 μg/mL when the control IC50 value of huperzine A was 0.0192 μg/mL. Molecular Docking Software (MOE) was used to discover molecular sites of action between biatractylolide and AChE protein by regular molecular docking approaches. Moreover, biatractylolide downregulated the expression of AChE of MEF and 293T cells in a dose-dependent manner. These results demonstrated that the molecular mechanisms of inhibitory activities of biatractylolide on AChE are not only through binding to AChE, but also via reducing AChE expression by inhibiting the activity of GSK3β.
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Abstract
After either acute psychological stress or exposure to acetylcholinesterase (AChE) inhibitors, long-lasting deleterious changes of a similar nature occur in the mammalian brain. We explored the molecular and neurophysiological mechanisms preceding these convergent delayed consequences in vivo and in perfused hippocampal brain slices. In stressed mice, we observed a disruption of the blood-brain barrier, which leads to efficient brain penetrance of anti-AChEs. This increase in penetrance of anti-AChEs, and consequently in acetylcholine (ACh) levels, induces a cascade of c-fos-mediated transcriptional responses dependent on intracellular Ca2+ accumulation. Consequently, the capacity for synthesis and vesicle packaging of ACh is suppressed simultaneously with enhanced AChE production that potentiates ACh hydrolysis. This bimodal decrease in ACh bioavailability, which is independent of the hypothalamic-pituitary-adrenal axis, then ter minates the initial neurophysiological excitation. In vivo, this AChE overexpression leads to enzyme accu mulation that is evident for more than 80 hr. The overexpressed enzyme can protect the brain from sustained hyperexcitability and from increased susceptibility to seizure activity and neuronal toxicity. However, exper imental accumulation of AChE in brain neurons through transgenic manipulations leads to a slowly pro gressive deterioration in cognitive and neuromotor faculties. The transcriptional consequences of stress and anti-AChEs may therefore be beneficial in the short term but deleterious in the long term. NEURO SCIENTIST 5:173-183, 1999
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Hollins SL, Cairns MJ. MicroRNA: Small RNA mediators of the brains genomic response to environmental stress. Prog Neurobiol 2016; 143:61-81. [PMID: 27317386 DOI: 10.1016/j.pneurobio.2016.06.005] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2016] [Revised: 05/24/2016] [Accepted: 06/11/2016] [Indexed: 01/09/2023]
Abstract
The developmental processes that establish the synaptic architecture of the brain while retaining capacity for activity-dependent remodeling, are complex and involve a combination of genetic and epigenetic influences. Dysregulation of these processes can lead to problems with neural circuitry which manifest in humans as a range of neurodevelopmental syndromes, such as schizophrenia, bipolar disorder and fragile X mental retardation. Recent studies suggest that prenatal, postnatal and intergenerational environmental factors play an important role in the aetiology of stress-related psychopathology. A number of these disorders have been shown to display epigenetic changes in the postmortem brain that reflect early life experience. These changes affect the regulation of gene expression though chromatin remodeling (transcriptional) and post-transcriptional influences, especially small noncoding microRNA (miRNA). These dynamic and influential molecules appear to play an important function in both brain development and its adaption to stress. In this review, we examine the role of miRNA in mediating the brain's response to both prenatal and postnatal environmental perturbations and explore how stress- induced alterations in miRNA expression can regulate the stress response via modulation of the immune system. Given the close relationship between environmental stress, miRNA, and brain development/function, we assert that miRNA hold a significant position at the molecular crossroads between neural development and adaptations to environmental stress. A greater understanding of the dynamics that mediate an individual's predisposition to stress-induced neuropathology has major human health benefits and is an important area of research.
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Affiliation(s)
- Sharon L Hollins
- School of Biomedical Sciences and Pharmacy and the Hunter Medical Research Institute, the University of Newcastle, Callaghan, NSW 2308, Australia
| | - Murray J Cairns
- School of Biomedical Sciences and Pharmacy and the Hunter Medical Research Institute, the University of Newcastle, Callaghan, NSW 2308, Australia; Schizophrenia Research Institute, Sydney, NSW, Australia.
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Li VWT, Tsui MPM, Chen X, Hui MNY, Jin L, Lam RHW, Yu RMK, Murphy MB, Cheng J, Lam PKS, Cheng SH. Effects of 4-methylbenzylidene camphor (4-MBC) on neuronal and muscular development in zebrafish (Danio rerio) embryos. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2016; 23:8275-8285. [PMID: 26888529 DOI: 10.1007/s11356-016-6180-9] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2014] [Accepted: 01/26/2016] [Indexed: 06/05/2023]
Abstract
The negative effects of overexposure to ultraviolet (UV) radiation in humans, including sunburn and light-induced cellular injury, are of increasing public concern. 4-Methylbenzylidene camphor (4-MBC), an organic chemical UV filter, is an active ingredient in sunscreen products. To date, little information is available about its neurotoxicity during early vertebrate development. Zebrafish embryos were exposed to various concentrations of 4-MBC in embryo medium for 3 days. In this study, a high concentration of 4-MBC, which is not being expected at the current environmental concentrations in the environment, was used for the purpose of phenotypic screening. Embryos exposed to 15 μM of 4-MBC displayed abnormal axial curvature and exhibited impaired motility. Exposure effects were found to be greatest during the segmentation period, when somite formation and innervation occur. Immunostaining of the muscle and axon markers F59, znp1, and zn5 revealed that 4-MBC exposure leads to a disorganized pattern of slow muscle fibers and axon pathfinding errors during the innervation of both primary and secondary motor neurons. Our results also showed reduction in AChE activity upon 4-MBC exposure both in vivo in the embryos (15 μM) and in vitro in mammalian Neuro-2A cells (0.1 μM), providing a possible mechanism for 4-MBC-induced muscular and neuronal defects. Taken together, our results have shown that 4-MBC is a teratogen and influences muscular and neuronal development, which may result in developmental defects.
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Affiliation(s)
- Vincent Wai Tsun Li
- State Key Laboratory in Marine Pollution, City University of Hong Kong, 83 Tat Chee Avenue, Hong Kong, SAR, China
- Department of Mechanical and Biomedical Engineering, City University of Hong Kong, 83 Tat Chee Avenue, Hong Kong, SAR, China
| | - Mei Po Mirabelle Tsui
- State Key Laboratory in Marine Pollution, City University of Hong Kong, 83 Tat Chee Avenue, Hong Kong, SAR, China
- Department of Biology and Chemistry, City University of Hong Kong, 83 Tat Chee Avenue, Hong Kong, SAR, China
| | - Xueping Chen
- State Key Laboratory in Marine Pollution, City University of Hong Kong, 83 Tat Chee Avenue, Hong Kong, SAR, China
- Department of Biology and Chemistry, City University of Hong Kong, 83 Tat Chee Avenue, Hong Kong, SAR, China
| | - Michelle Nga Yu Hui
- Department of Biology and Chemistry, City University of Hong Kong, 83 Tat Chee Avenue, Hong Kong, SAR, China
| | - Ling Jin
- State Key Laboratory in Marine Pollution, City University of Hong Kong, 83 Tat Chee Avenue, Hong Kong, SAR, China
- Department of Biology and Chemistry, City University of Hong Kong, 83 Tat Chee Avenue, Hong Kong, SAR, China
| | - Raymond H W Lam
- Department of Mechanical and Biomedical Engineering, City University of Hong Kong, 83 Tat Chee Avenue, Hong Kong, SAR, China
| | - Richard Man Kit Yu
- School of Environmental and Life Sciences, The University of Newcastle, University Drive, Callaghan, NSW, 2308, Australia
| | - Margaret B Murphy
- State Key Laboratory in Marine Pollution, City University of Hong Kong, 83 Tat Chee Avenue, Hong Kong, SAR, China
- Department of Biology and Chemistry, City University of Hong Kong, 83 Tat Chee Avenue, Hong Kong, SAR, China
| | - Jinping Cheng
- State Key Laboratory in Marine Pollution, City University of Hong Kong, 83 Tat Chee Avenue, Hong Kong, SAR, China
- Department of Biology and Chemistry, City University of Hong Kong, 83 Tat Chee Avenue, Hong Kong, SAR, China
| | - Paul Kwan Sing Lam
- State Key Laboratory in Marine Pollution, City University of Hong Kong, 83 Tat Chee Avenue, Hong Kong, SAR, China
- Department of Biology and Chemistry, City University of Hong Kong, 83 Tat Chee Avenue, Hong Kong, SAR, China
| | - Shuk Han Cheng
- State Key Laboratory in Marine Pollution, City University of Hong Kong, 83 Tat Chee Avenue, Hong Kong, SAR, China.
- Department of Biomedical Science, City University of Hong Kong, 83 Tat Chee Avenue SAR, Hong Kong, China.
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15
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Hallgren S, Fredriksson A, Viberg H. More signs of neurotoxicity of surfactants and flame retardants - Neonatal PFOS and PBDE 99 cause transcriptional alterations in cholinergic genes in the mouse CNS. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2015; 40:409-416. [PMID: 26254212 DOI: 10.1016/j.etap.2015.06.014] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Accepted: 06/08/2015] [Indexed: 06/04/2023]
Abstract
Maternally and lactionally transferred persistent organic pollutants may interfere with CNS development. Here, 10-day-old male mice were exposed to single oral doses of PFOS (perflourooctanosulphonate) or PBDE 99 (2,2',4,4',5-penta-bromodiphenyl ether), and examined for changes in cholinergic gene transcription in the CNS 24h and 7 weeks later. 24h after exposure qPCR analyses revealed decreased transcription of nAChR-β2 and AChE in cortex, and increased mAChR-5 in hippocampus of PFOS treated mice. Neonatal PFOS treatment altered spontaneous behaviour at 2 months of age but did not affect gene transcription in adults. At 2 months of age neonatally PBDE 99 treated mice had altered spontaneous behaviour, and cortical transcription of AChE, nAChR-α4, nAChR-β2 and mAChR-5 were elevated. Our results indicate that PFOS and PBDE 99 affects the developing central cholinergic system by altering gene transcription in cortex and hippocampus, which may in part account for mechanisms causing changes in spontaneous behaviour.
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Affiliation(s)
- Stefan Hallgren
- Department of Environmental Toxicology, Uppsala University, Norbyvägen 18A, S-752 36 Uppsala, Sweden.
| | - Anders Fredriksson
- Department of Environmental Toxicology, Uppsala University, Norbyvägen 18A, S-752 36 Uppsala, Sweden
| | - Henrik Viberg
- Department of Environmental Toxicology, Uppsala University, Norbyvägen 18A, S-752 36 Uppsala, Sweden
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16
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Rosenberg YJ, Walker J, Jiang X, Donahue S, Robosky J, Sack M, Lees J, Urban L. A highly stable minimally processed plant-derived recombinant acetylcholinesterase for nerve agent detection in adverse conditions. Sci Rep 2015; 5:13247. [PMID: 26268538 PMCID: PMC4642508 DOI: 10.1038/srep13247] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2015] [Accepted: 07/22/2015] [Indexed: 11/09/2022] Open
Abstract
Although recent innovations in transient plant systems have enabled gram quantities of proteins in 1-2 weeks, very few have been translated into applications due to technical challenges and high downstream processing costs. Here we report high-level production, using a Nicotiana benthamiana/p19 system, of an engineered recombinant human acetylcholinesterase (rAChE) that is highly stable in a minimally processed leaf extract. Lyophylized clarified extracts withstand prolonged storage at 70 °C and, upon reconstitution, can be used in several devices to detect organophosphate (OP) nerve agents and pesticides on surfaces ranging from 0 °C to 50 °C. The recent use of sarin in Syria highlights the urgent need for nerve agent detection and countermeasures necessary for preparedness and emergency responses. Bypassing cumbersome and expensive downstream processes has enabled us to fully exploit the speed, low cost and scalability of transient production systems resulting in the first successful implementation of plant-produced rAChE into a commercial biotechnology product.
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Affiliation(s)
| | | | | | | | | | - Markus Sack
- Institute for molecular Biotechnology, RWTH Aachen University, Aachen, Germany
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17
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Xu ML, Luk WKW, Lau KM, Bi CWC, Cheng AWM, Gong AGW, Lin H, Tsim KWK. Three N-Glycosylation Sites of Human Acetylcholinesterase Shares Similar Glycan Composition. J Mol Neurosci 2015; 57:486-91. [PMID: 26231935 DOI: 10.1007/s12031-015-0629-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Accepted: 07/21/2015] [Indexed: 11/29/2022]
Abstract
Acetylcholinesterase (AChE; EC 3.1.1.7) is a glycoprotein possessing three conserved N-linked glycosylation sites in mammalian species, locating at 296, 381, and 495 residues of the human sequence. Several lines of evidence demonstrated that N-glycosylation of AChE affected the enzymatic activity, as well as its biosynthesis. In order to determine the role of three N-glycosylation sites in AChE activity and glycan composition, the site-directed mutagenesis of N-glycosylation sites in wild-type human AChE(T) sequence was employed to generate the single-site mutants (i.e., AChE(T) (N296Q), AChET (N381Q), and AChE(T) (N495Q)) and all site mutant (i.e., AChE(T) (3N→3Q)). The mutation did not affect AChE protein expression in the transfected cells. The mutants, AChE(T) (3N→3Q) and AChE(T) (N381Q), showed very minimal enzymatic activity, while the other mutants showed reduced activity. By binding to lectins, Con A, and SNA, the glycosylation profile was revealed in those mutated AChE. The binding affinity with lectins showed no significant difference between various N-glycosylation mutants, which suggested that similar glycan composition should be resulted from different N-glycosylation sites. Although the three glycosylation sites within AChE sequence have different extent in affecting the enzymatic activity, their glycan compositions are very similar.
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Affiliation(s)
- Miranda L Xu
- Division of Life Science and Center for Chinese Medicine, The Hong Kong University of Science and Technology, Clear Water Bay Road, Hong Kong, China
| | - Wilson K W Luk
- Division of Life Science and Center for Chinese Medicine, The Hong Kong University of Science and Technology, Clear Water Bay Road, Hong Kong, China
| | - Kei M Lau
- Division of Life Science and Center for Chinese Medicine, The Hong Kong University of Science and Technology, Clear Water Bay Road, Hong Kong, China
| | - Cathy W C Bi
- Division of Life Science and Center for Chinese Medicine, The Hong Kong University of Science and Technology, Clear Water Bay Road, Hong Kong, China
| | - Anthony W M Cheng
- Division of Life Science and Center for Chinese Medicine, The Hong Kong University of Science and Technology, Clear Water Bay Road, Hong Kong, China
| | - Amy G W Gong
- Division of Life Science and Center for Chinese Medicine, The Hong Kong University of Science and Technology, Clear Water Bay Road, Hong Kong, China
| | - Huangquan Lin
- Division of Life Science and Center for Chinese Medicine, The Hong Kong University of Science and Technology, Clear Water Bay Road, Hong Kong, China
| | - Karl W K Tsim
- Division of Life Science and Center for Chinese Medicine, The Hong Kong University of Science and Technology, Clear Water Bay Road, Hong Kong, China.
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18
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de Assis CRD, Linhares AG, Oliveira VM, França RCP, Santos JF, Marcuschi M, Carvalho EVMM, Bezerra RS, Carvalho LB. Characterization of catalytic efficiency parameters of brain cholinesterases in tropical fish. FISH PHYSIOLOGY AND BIOCHEMISTRY 2014; 40:1659-1668. [PMID: 24980148 DOI: 10.1007/s10695-014-9956-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2013] [Accepted: 06/23/2014] [Indexed: 06/03/2023]
Abstract
Brain cholinesterases from four fish (Arapaima gigas, Colossoma macropomum, Rachycentron canadum and Oreochromis niloticus) were characterized using specific substrates and selective inhibitors. Parameters of catalytic efficiency such as activation energy (AE), k(cat) and k(cat)/k(m) as well as rate enhancements produced by these enzymes were estimated by a method using crude extracts described here. Despite the BChE-like activity, specific substrate kinetic analysis pointed to the existence of only acetylcholinesterase (AChE) in brain of the species studied. Selective inhibition suggests that C. macropomum brain AChE presents atypical activity regarding its behavior in the presence of selective inhibitors. AE data showed that the enzymes increased the rate of reactions up to 10(12) in relation to the uncatalyzed reactions. Zymograms showed the presence of AChE isoforms with molecular weights ranging from 202 to 299 kDa. Values of k(cat) and k(cat)/k(m) were similar to those found in the literature.
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Affiliation(s)
- Caio Rodrigo Dias de Assis
- Laboratório de Enzimologia - LABENZ, Departamento de Bioquímica and Laboratório de Imunopatologia Keizo Asami - LIKA, Universidade Federal de Pernambuco, Campus Universitário, Recife, PE, 50670-901, Brazil,
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19
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Sugahara Y, Kawaguchi M, Itoyama T, Kurokawa D, Tosa Y, Kitamura SI, Handoh IC, Nakayama K, Murakami Y. Pyrene induces a reduction in midbrain size and abnormal swimming behavior in early-hatched pufferfish larvae. MARINE POLLUTION BULLETIN 2014; 85:479-486. [PMID: 24793779 DOI: 10.1016/j.marpolbul.2014.04.022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Revised: 04/01/2014] [Accepted: 04/08/2014] [Indexed: 06/03/2023]
Abstract
Spills of heavy oil (HO) have an adverse effect on marine life. We have demonstrated previously that exposure to HO by fertilized eggs of the pufferfish (Takifugu rubripes) induces neural disruption and behavioral abnormality in early-hatched larvae. Here, two kinds of polycyclic aromatic hydrocarbons, pyrene and phenanthrene, were selected to examine their toxic effects on larval behavior of another pufferfish species (T. niphobles). Larvae exposed to pyrene or phenanthrene exhibited no abnormalities in morphology. However, those exposed to pyrene but not phenanthrene swam in an uncoordinated manner, although their swimming distance and speed were normal. The optic tectum, a part of the midbrain, of pyrene-exposed larvae did not grow to full size. Thus, these findings are indicated that pyrene might be a contributor to the behavioral and neuro-developmental toxicity, although there is no indication that it is the only compound participating in the toxicity of the heavy oil mixture.
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Affiliation(s)
- Yuki Sugahara
- Graduate School of Science and Engineering, Ehime University, 2-5 Bunkyo-cho, Matsuyama, Japan
| | - Masahumi Kawaguchi
- Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama, Japan
| | - Tatsuya Itoyama
- Graduate School of Science and Engineering, Ehime University, 2-5 Bunkyo-cho, Matsuyama, Japan
| | - Daisuke Kurokawa
- Misaki Marine Biological Station, The University of Tokyo, 1024 Koajiro, Misaki, Miura, Japan
| | - Yasuhiko Tosa
- Graduate School of Science and Engineering, Ehime University, 2-5 Bunkyo-cho, Matsuyama, Japan
| | - Shin-Ichi Kitamura
- Center for Marine Environmental Studies (CMES), Ehime University, 2-5 Bunkyo-cho, Matsuyama, Japan
| | - Itsuki C Handoh
- The Futurability Initiatives, Research Institute for Humanity and Nature, 457-4 Motoyama, Kamigamo, Kita-ku, Kyoto, Japan
| | - Kei Nakayama
- Center for Marine Environmental Studies (CMES), Ehime University, 2-5 Bunkyo-cho, Matsuyama, Japan.
| | - Yasunori Murakami
- Graduate School of Science and Engineering, Ehime University, 2-5 Bunkyo-cho, Matsuyama, Japan.
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20
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Campanha HM, Carvalho F, Schlosser PM. Active and peripheral anionic sites of acetylcholinesterase have differential modulation effects on cell proliferation, adhesion and neuritogenesis in the NG108-15 cell line. Toxicol Lett 2014; 230:122-31. [PMID: 24680925 DOI: 10.1016/j.toxlet.2014.03.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2013] [Revised: 03/02/2014] [Accepted: 03/19/2014] [Indexed: 11/26/2022]
Abstract
The classical enzymatic role of acetylcholinesterase (AChE) is to terminate impulse transmission at cholinergic synapses through rapid hydrolysis of acetylcholine (ACh). Inactivation of this enzyme's catalytic site is the primary mechanism of acute toxicity of OP insecticides (e.g. parathion, chlorpyrifos). There is now sufficient evidence to suggest that AChE has a neurotrophic function that may be altered by organophosphate (OP) exposure, resulting in defects of neuronal growth and development, though the clarification of the mechanisms involved require further in vitro investigation. In the present study, the mouse neuroblastoma×rat glioma hybrid NG108-15 cell line was used to investigate the differential effects between inhibition of the catalytic site and peripheral anionic site (PAS) of acetylcholinesterase (AChE) on cell adhesion, proliferation and neuritogenesis, in the presence and absence of human red blood cell (hRBC) AChE (ED3.1.1.7). AChE active-site inhibitor paraoxon (PO; 0.1-1.0μM), when added to NG108-15 cells grown on AChE-coated plates, had no effect on cell proliferation, but exerted a significant reduction in strongly adherent viable cells accompanied by mostly short process formations, with 18% of cells considered to be neuritogenic, similar to that observed on uncoated plates. In contrast, PO had no significant effect on cell adhesion and proliferation of NG108-15 cells on uncoated plates. The PAS-ligand thioflavin-T (Th-T; 0.5-25μM), however, decreased cell adhesion and proliferation, on both uncoated and ACh-E coated plates, with less magnitude on AChE-coated plates. Taken together, these results suggest that strong cell adherence and neuritogenesis are sensitive to PO in this cell culture model, with no impact on proliferation, in the presence of membrane bound AChE-coating, while there is no sensitivity to PO on uncoated plates. On the other hand, binding of Th-T directly to the PAS affects both cell adherence and proliferation, with less magnitude in the presence of membrane-bound AChE. The current study indicates that PO is deleterious in neural development during critical periods of strong cell adhesion and differentiation, interfering with AChE trophic function.
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Affiliation(s)
- Helen M Campanha
- Rutgers, New Jersey Medical School-Graduate School of Biomedical Sciences, 185 South Orange Avenue, MSB H609, Newark, NJ 07103, United States.
| | - Félix Carvalho
- REQUIMTE, Laboratory of Toxicology, Department of Biological Sciences, Faculty of Pharmacy, University of Porto, Rua de Jorge Viterbo Ferreira no. 228, 4050-313 Porto, Portugal
| | - Paul M Schlosser
- U.S. Environmental Protection Agency, National Center for Environmental Assessment, Washington, DC, United States
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21
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Xiang YY, Dong H, Yang BB, Macdonald JF, Lu WY. Interaction of acetylcholinesterase with neurexin-1β regulates glutamatergic synaptic stability in hippocampal neurons. Mol Brain 2014; 7:15. [PMID: 24594013 PMCID: PMC3973991 DOI: 10.1186/1756-6606-7-15] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2013] [Accepted: 02/27/2014] [Indexed: 02/11/2023] Open
Abstract
Background Excess expression of acetylcholinesterase (AChE) in the cortex and hippocampus causes a decrease in the number of glutamatergic synapses and alters the expression of neurexin and neuroligin, trans-synaptic proteins that control synaptic stability. The molecular sequence and three-dimensional structure of AChE are homologous to the corresponding aspects of the ectodomain of neuroligin. This study investigated whether excess AChE interacts physically with neurexin to destabilize glutamatergic synapses. Results The results showed that AChE clusters colocalized with neurexin assemblies in the neurites of hippocampal neurons and that AChE co-immunoprecipitated with neurexin from the lysate of these neurons. Moreover, when expressed in human embryonic kidney 293 cells, N-glycosylated AChE co-immunoprecipitated with non-O–glycosylated neurexin-1β, with N-glycosylation of the AChE being required for this co-precipitation to occur. Increasing extracellular AChE decreased the association of neurexin with neuroligin and inhibited neuroligin-induced synaptogenesis. The number and activity of excitatory synapses in cultured hippocampal neurons were reduced by extracellular catalytically inactive AChE. Conclusions Excessive glycosylated AChE could competitively disrupt a subset of the neurexin–neuroligin junctions consequently impairing the integrity of glutamatergic synapses. This might serve a molecular mechanism of excessive AChE induced neurodegeneration.
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Affiliation(s)
| | | | | | | | - Wei-Yang Lu
- Robarts Research Institute, University of Western Ontario, London, Ontario, Canada.
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22
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Acetylcholinesterase Protein Level Is Preserved in the Alzheimer's Brain. J Mol Neurosci 2013; 53:446-53. [DOI: 10.1007/s12031-013-0183-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2013] [Accepted: 11/12/2013] [Indexed: 01/15/2023]
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Acetylcholinesterase as a biomarker in environmental and occupational medicine: new insights and future perspectives. BIOMED RESEARCH INTERNATIONAL 2013; 2013:321213. [PMID: 23936791 PMCID: PMC3727120 DOI: 10.1155/2013/321213] [Citation(s) in RCA: 212] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/27/2013] [Accepted: 06/20/2013] [Indexed: 01/23/2023]
Abstract
Acetylcholinesterase (AChE) is a key enzyme in the nervous system. It terminates nerve impulses by catalysing the hydrolysis of neurotransmitter acetylcholine. As a specific molecular target of organophosphate and carbamate pesticides, acetylcholinesterase activity and its inhibition has been early recognized to be a human biological marker of pesticide poisoning. Measurement of AChE inhibition has been increasingly used in the last two decades as a biomarker of effect on nervous system following exposure to organophosphate and carbamate pesticides in occupational and environmental medicine. The success of this biomarker arises from the fact that it meets a number of characteristics necessary for the successful application of a biological response as biomarker in human biomonitoring: the response is easy to measure, it shows a dose-dependent behavior to pollutant exposure, it is sensitive, and it exhibits a link to health adverse effects. The aim of this work is to review and discuss the recent findings about acetylcholinesterase, including its sensitivity to other pollutants and the expression of different splice variants. These insights open new perspective for the future use of this biomarker in environmental and occupational human health monitoring.
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López-Granero C, Cardona D, Giménez E, Lozano R, Barril J, Sánchez-Santed F, Cañadas F. Chronic dietary exposure to chlorpyrifos causes behavioral impairments, low activity of brain membrane-bound acetylcholinesterase, and increased brain acetylcholinesterase-R mRNA. Toxicology 2013; 308:41-9. [PMID: 23545134 DOI: 10.1016/j.tox.2013.03.009] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2013] [Revised: 03/19/2013] [Accepted: 03/21/2013] [Indexed: 01/20/2023]
Abstract
Chlorpyrifos (CPF) is an organophosphate (OP) insecticide that is metabolically activated to the highly toxic chlorpyrifos oxon. Dietary exposure is the main route of intoxication for non-occupational exposures. However, only limited behavioral effects of chronic dietary exposure have been investigated. Therefore, male Wistar rats were fed a dose of 5mg/kg/day of CPF for thirty-one weeks. Animals were evaluated in spatial learning and impulsivity tasks after 21 weeks of CPF dietary exposure and one week after exposure ended, respectively. In addition, the degree of inhibition of brain acetylcholinesterase (AChE) was evaluated for both the soluble and particulate forms of the enzyme, as well as AChE gene expression. Also, brain acylpeptide hydrolase (APH) was investigated as an alternative target for OP-mediated effects. All variables were evaluated at various time points in response to CPF diet and after exposure ended. Results from behavioral procedures suggest cognitive and emotional disorders. Moreover, low levels of activity representing membrane-bound oligomeric forms (tetramers) were also observed. In addition, increased brain AChE-R mRNA levels were detected after four weeks of CPF dietary exposure. However, no changes in levels of brain APH were observed among groups. In conclusion, our data point to a relationship between cognitive impairments and changes in AChE forms, specifically to a high inhibition of the particulate form and a modification of alternative splicing of mRNA during CPF dietary exposure.
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Affiliation(s)
- Caridad López-Granero
- Departamento de Psicología, Universidad de Almería, Campus de Excelencia Internacional Agroalimentario CeiA3, La Cañada, 04120, Almería, Spain
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25
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He C, Wang C, Li B, Wu M, Geng H, Chen Y, Zuo Z. Exposure of Sebastiscus marmoratus embryos to pyrene results in neurodevelopmental defects and disturbs related mechanisms. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2012; 116-117:109-115. [PMID: 22487263 DOI: 10.1016/j.aquatox.2012.03.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2011] [Revised: 03/13/2012] [Accepted: 03/13/2012] [Indexed: 05/31/2023]
Abstract
Polycyclic aromatic hydrocarbons (PAHs) are widespread environmental contaminants, which are known to be carcinogenic and teratogenic. These compounds cause a range of macroscopic malformations, particularly to the craniofacial apparatus and cardiovascular system during vertebrate development. However, little is known concerning microscopic effects, especially on the sensitive early life stages or on the molecular basis of developmental neurotoxicity. Using the rockfish (Sebastiscus marmoratus), we explored the neurodevelopmental defects caused by early-life exposure to environmentally relevant concentrations of pyrene, a 4-ring PAH. The results showed that pyrene substantially disrupted the cranial innervation pattern and caused deficiency of motor nerves. The expression of a protein associated with axon growth, growth associated protein 43, was decreased in the central nervous system after treatment with pyrene. N-methyl-D-aspartate receptor (NMDAR) plays a vital role in a variety of processes, including neuronal development, synaptic plasticity, and neuronal survival and death. Our results showed that the expression of Ca²⁺/calmodulin dependent kinase II and cAMP-response element-binding, which belong to the NMDAR pathway, were increased in a dose-dependent manner after exposure to pyrene. Acetylcholine, an important neurotransmitter which is known to suppress retinal cells neurite outgrowth, was increased by pyrene exposure. Nitric oxide (NO) acts as an activity-dependent retrograde signal that can coordinate axonal targeting and synaptogenesis during development. The level of NO was decreased in a dose-dependent manner following exposure to pyrene. Taken together, the defects in neurodevelopment and the damage to related mechanisms provided the basis for a better understanding of the neurotoxic effects of pyrene.
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Affiliation(s)
- Chengyong He
- Key Laboratory of Ministry of Education for Subtropical Wetland Ecosystem Research, School of Life Sciences, Xiamen University, Xiamen, China
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26
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Sperling LE, Klaczinski J, Schütz C, Rudolph L, Layer PG. Mouse acetylcholinesterase enhances neurite outgrowth of rat R28 cells through interaction with laminin-1. PLoS One 2012; 7:e36683. [PMID: 22570738 PMCID: PMC3343015 DOI: 10.1371/journal.pone.0036683] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2012] [Accepted: 04/11/2012] [Indexed: 02/02/2023] Open
Abstract
The enzyme acetylcholinesterase (AChE) terminates synaptic transmission at cholinergic synapses by hydrolyzing the neurotransmitter acetylcholine, but can also exert 'non-classical', morpho-regulatory effects on developing neurons such as stimulation of neurite outgrowth. Here, we investigated the role of AChE binding to laminin-1 on the regulation of neurite outgrowth by using cell culture, immunocytochemistry, and molecular biological approaches. To explore the role of AChE, we examined fiber growth of cells overexpressing different forms of AChE, and/or during their growth on laminin-1. A significant increase of neuritic growth as compared with controls was observed for neurons over-expressing AChE. Accordingly, addition of globular AChE to the medium increased total length of neurites. Co-transfection with PRIMA, a membrane anchor of AChE, led to an increase in fiber length similar to AChE overexpressing cells. Transfection with an AChE mutant that leads to the retention of AChE within cells had no stimulatory effect on neurite length. Noticeably, the longest neurites were produced by neurons overexpressing AChE and growing on laminin-1, suggesting that the AChE/laminin interaction is involved in regulating neurite outgrowth. Our findings demonstrate that binding of AChE to laminin-1 alters AChE activity and leads to increased neurite growth in culture. A possible mechanism of the AChE effect on neurite outgrowth is proposed due to the interaction of AChE with laminin-1.
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Affiliation(s)
- Laura E Sperling
- Entwicklungsbiologie und Neurogenetik, Fachbereich Biologie, Technische Universität Darmstadt, Darmstadt, Germany.
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Nalivaeva NN, Makova NZ, Kochkina EG, John D, Arutyunov VA, Kozina LS, Arutjunyan AV, Zhuravin IA. Effects of geroprotective peptides on the activity of cholinesterases and formation of the soluble form of the amyloid precursor protein in human neuroblastoma SH-SY5Y cells. NEUROCHEM J+ 2011. [DOI: 10.1134/s1819712411030044] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Yang D, Lauridsen H, Buels K, Chi LH, La Du J, Bruun DA, Olson JR, Tanguay RL, Lein PJ. Chlorpyrifos-oxon disrupts zebrafish axonal growth and motor behavior. Toxicol Sci 2011; 121:146-59. [PMID: 21346248 DOI: 10.1093/toxsci/kfr028] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Axonal morphology is a critical determinant of neuronal connectivity, and perturbation of the rate or extent of axonal growth during development has been linked to neurobehavioral deficits in animal models and humans. We previously demonstrated that the organophosphorus pesticide (OP) chlorpyrifos (CPF) inhibits axonal growth in cultured neurons. In this study, we used a zebrafish model to determine whether CPF, its oxon metabolite (CPFO), or the excreted metabolite trichloro-2-pyridinol (TCPy) alter spatiotemporal patterns of axonal growth in vivo. Static waterborne exposure to CPFO, but not CPF or TCPy, at concentrations ≥ 0.03 μM from 24- to 72-h post fertilization significantly inhibited acetylcholinesterase, and high-performance liquid chromatography detected significantly more TCPy in zebrafish exposed to 0.1 μM CPFO versus 1.0 μM CPF. These data suggest that zebrafish lack the metabolic enzymes to activate CPF during these early developmental stages. Consistent with this, CPFO, but not CPF, significantly inhibited axonal growth of sensory neurons, primary motoneurons, and secondary motoneurons at concentrations ≥ 0.1 μM. Secondary motoneurons were the most sensitive to axonal growth inhibition by CPFO, which was observed at concentrations that did not cause mortality, gross developmental defects, or aberrant somatic muscle differentiation. CPFO effects on axonal growth correlated with adverse effects on touch-induced swimming behavior, suggesting the functional relevance of these structural changes. These data suggest that altered patterns of neuronal connectivity contribute to the developmental neurotoxicity of CPF and demonstrate the relevance of zebrafish as a model for studying OP developmental neurotoxicity.
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Affiliation(s)
- Dongren Yang
- Department of Molecular Biosciences, University of California Davis School of Veterinary Medicine, Davis, California 95616, USA
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29
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Bodur E, Layer PG. Counter-regulation of cholinesterases: differential activation of PKC and ERK signaling in retinal cells through BChE knockdown. Biochimie 2010; 93:469-76. [PMID: 21094673 DOI: 10.1016/j.biochi.2010.10.020] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2010] [Accepted: 10/31/2010] [Indexed: 10/18/2022]
Abstract
The ubiquitous cholinesterase (ChE) enzymes, functioning in the termination of acetylcholine mediated neural transmission, are also reported to have additional functions. Through application of siRNAs against butyrylcholinesterase (BChE) in R28 cells, a retinal cell line with pluripotent properties, a counter-regulation between ChEs was revealed. BChE knock down resulted in an up-regulation of not only acetylcholinesterase (AChE), but also altered the signaling status of PKC and ERK. Knockdown of BChE modified ERK signaling most notably through ERK1/2 proteins, together with the transcription activator P90RSK1 and c-fos. Stimulation of the R28 cell line by forskolin revealed that ChEs are involved in an intricate cross talk between different signaling pathways. Forskolin-stimulated R28 cells displayed a robust cholinergic response, as detected by both electrophysiology and ChE expression, and changed the activation status of PKC/ERK signaling pathways. The findings in R28 cells show that ChE expressions are inversely co-regulated and act through the transcription factors c-fos and P90RSK1. Since R28 cells have the capacity to differentiate into different cell types through stimulation of signaling pathways, ChEs are likely to be associated with cell fate determination, rather than just terminating cholinergic responses.
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Affiliation(s)
- Ebru Bodur
- Hacettepe University, Faculty of Medicine, Department of Biochemistry, Sıhhiye, Ankara, Turkey.
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Karczmar AG. Cholinesterases (ChEs) and the cholinergic system in ontogenesis and phylogenesis, and non-classical roles of cholinesterases—A review. Chem Biol Interact 2010; 187:34-43. [DOI: 10.1016/j.cbi.2010.03.009] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2009] [Revised: 02/16/2010] [Accepted: 03/03/2010] [Indexed: 12/24/2022]
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31
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Gui CZ, Ran LY, Li JP, Guan ZZ. Changes of learning and memory ability and brain nicotinic receptors of rat offspring with coal burning fluorosis. Neurotoxicol Teratol 2010; 32:536-41. [PMID: 20381606 DOI: 10.1016/j.ntt.2010.03.010] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2010] [Revised: 03/31/2010] [Accepted: 03/31/2010] [Indexed: 10/19/2022]
Abstract
The purpose of the investigation is to reveal the mechanism of the decreased ability of learning and memory induced by coal burning fluorosis. Ten offspring SD rats aged 30days, who were born from the mothers with chronic coal burning fluorosis, and ten offspring with same age from the normal mothers as controls were selected. Spatial learning and memory of the rats were evaluated by Morris Water Maze test. Cholinesterase activity was detected by photometric method. The expressions of nicotinic acetylcholine receptors (nAChRs) at protein and mRNA levels were detected by Western blotting and Real-time PCR, respectively. The results showed that in the rat offspring exposed to higher fluoride as compared to controls, the learning and memory ability declined; the cholinesterase activities in the brains were inhibited; the protein levels of alpha3, alpha4 and alpha7 nAChR subunits were decreased which showed certain significant correlations with the declined learning and memory ability; and the mRNA levels of alpha3 and alpha4 nAChRs were decreased, whereas the alpha7 mRNA increased. The data indicated that coal burning fluorosis can induce the decreased ability of learning and memory of rat offspring, in which the mechanism might be connected to the changed nAChRs and cholinesterase.
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Affiliation(s)
- Chuan-Zhi Gui
- Department of Pathology in Guiyang Medical College, Guiyang, P.R. China
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32
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Xie HQ, Liang D, Leung KW, Chen VP, Zhu KY, Chan WKB, Choi RCY, Massoulié J, Tsim KWK. Targeting acetylcholinesterase to membrane rafts: a function mediated by the proline-rich membrane anchor (PRiMA) in neurons. J Biol Chem 2010; 285:11537-46. [PMID: 20147288 DOI: 10.1074/jbc.m109.038711] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
In the mammalian brain, acetylcholinesterase (AChE) is anchored in cell membranes by a transmembrane protein PRiMA (proline-rich membrane anchor). We present evidence that at least part of the PRiMA-linked AChE is integrated in membrane microdomains called rafts. A significant proportion of PRiMA-linked AChE tetramers from rat brain was recovered in raft fractions; this proportion was markedly higher at low rather than at high concentrations of cold Triton X-100. The detergent-resistant fraction increased during brain development. In NG108-15 neuroblastoma cells transfected with cDNAs encoding AChE(T) and PRiMA, PRiMA-linked G(4) AChE was found in membrane rafts and showed the same sensitivity to cold Triton X-100 extraction as in the brain. The association of PRiMA-linked AChE with rafts was weaker than that of glycosylphosphatidylinositol-anchored G(2) AChE or G(4) Q(N)-H(C)-linked AChE. It was found to depend on the presence of a cholesterol-binding motif, called CRAC (cholesterol recognition/interaction amino acid consensus), located at the junction of transmembrane and cytoplasmic domains of both PRiMA I and II isoforms. The cytoplasmic domain of PRiMA, which differs between PRiMA I and PRiMA II, appeared to play some role in stabilizing the raft localization of G(4) AChE, because the Triton X-100-resistant fraction was smaller with the shorter PRiMA II isoform than that with the longer PRiMA I isoform.
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Affiliation(s)
- Heidi Q Xie
- Department of Biology and Center for Chinese Medicine, The Hong Kong University of Science and Technology, Clear Water Bay Road, Kowloon, Hong Kong
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Slotkin TA, Ryde IT, Wrench N, Card JA, Seidler FJ. Nonenzymatic role of acetylcholinesterase in neuritic sprouting: regional changes in acetylcholinesterase and choline acetyltransferase after neonatal 6-hydroxydopamine lesions. Neurotoxicol Teratol 2009; 31:183-6. [PMID: 19452616 DOI: 10.1016/j.ntt.2008.12.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Acetylcholinesterase (AChE) is postulated to play a nonenzymatic role in the development of neuritic projections. We gave the specific neurotoxin, 6-OHDA to rats on postnatal day (PN) 1, a treatment that destroys noradrenergic nerve terminals in the forebrain while producing reactive sprouting in the brainstem. AChE showed profound decreases in the forebrain that persisted in males over the entire phase of major synaptogenesis, from PN4 through PN21; in the brainstem, AChE was increased. Parallel examinations of choline acetyltransferase, an enzymatic marker for cholinergic nerve terminals, showed a different pattern of 6-OHDA-induced alterations, with initial decreases in both forebrain and brainstem in males and regression toward normal by PN21; females were far less affected. The sex differences are in accord with the greater plasticity of the female brain and its more rapid recovery from neurotoxic injury; our findings indicate that these differences are present well before puberty. These results support the view that AChE is involved in neurite formation, unrelated to its enzymatic role in cholinergic neurotransmission. Further, the results for choline acetyltransferase indicate that early depletion of norepinephrine compromises development of acetylcholine systems, consistent with a trophic role for this neurotransmitter.
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Affiliation(s)
- Theodore A Slotkin
- Department of Pharmacology & Cancer Biology, Duke University Medical Center, Durham, North Carolina, 27710, USA.
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Abstract
Myasthenia gravis (MG) is an autoimmune disorder usually caused by antibodies against either the acetylcholine receptor (AChR) or muscle-specific tyrosine kinase (MuSK) at the neuromuscular junction. Neuromuscular transmission failure results in muscle fatigue and weakness that can be treated symptomatically with acetylcholinesterase inhibitors (AChEIs). Long-term treatment with nonselective AChEIs may have considerable drawbacks; thus, this medication is ideally tapered when strength improves. Patients with AChR antibodies respond beneficially to treatment, whereas patients with MuSK antibodies generally do not. Recently, the selective AChEI EN101, which specifically targets the isoform of "read-through" AChE (AChE-R), has been developed and may be of importance for symptomatic relief in AChR-antibody seropositive MG. This article is a review of the mechanisms, therapeutic effects, and drawbacks, with both old and new AChEIs in MG.
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Affiliation(s)
- Anna Rostedt Punga
- Department of Clinical Neurophysiology, Uppsala University Hospital, 75185 Uppsala, Sweden.
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Bond CE, Zimmermann M, Greenfield SA. Upregulation of alpha7 Nicotinic Receptors by Acetylcholinesterase C-Terminal Peptides. PLoS One 2009; 4:e4846. [PMID: 19287501 PMCID: PMC2654408 DOI: 10.1371/journal.pone.0004846] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2008] [Accepted: 01/29/2009] [Indexed: 11/25/2022] Open
Abstract
Background The alpha-7 nicotinic acetylcholine receptor (α7-nAChR) is well known as a potent calcium ionophore that, in the brain, has been implicated in excitotoxicity and hence in the underlying mechanisms of neurodegenerative disorders such as Alzheimer's disease. Previous research implied that the activity of this receptor may be modified by exposure to a peptide fragment derived from the C-terminal region of the enzyme acetylcholinesterase. This investigation was undertaken to determine if the functional changes observed could be attributed to peptide binding interaction with the α7-nAChR, or peptide modulation of receptor expression. Methodology/Principal Findings This study provides evidence that two peptides derived from the C-terminus of acetylcholinesterase, not only selectively displace specific bungarotoxin binding at the α7-nAChR, but also alter receptor binding properties for its familiar ligands, including the alternative endogenous agonist choline. Of more long-term significance, these peptides also induce upregulation of α7-nAChR mRNA and protein expression, as well as enhancing receptor trafficking to the plasma membrane. Conclusions/Significance The results reported here demonstrate a hitherto unknown relationship between the α7-nAChR and the non-enzymatic functions of acetylcholinesterase, mediated independently by its C-terminal domain. Such an interaction may prove valuable as a pharmacological tool, prompting new approaches for understanding, and combating, the process of neurodegeneration.
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Affiliation(s)
- Cherie E Bond
- Institute for the Future of the Mind, Department of Pharmacology, Oxford University, Oxford, UK.
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Liang D, Blouet JP, Borrega F, Bon S, Massoulié J. Respective roles of the catalytic domains and C-terminal tail peptides in the oligomerization and secretory trafficking of human acetylcholinesterase and butyrylcholinesterase. FEBS J 2009; 276:94-108. [PMID: 19019080 DOI: 10.1111/j.1742-4658.2008.06756.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Butyrylcholinesterase (BChE) and the T splice variant of acetylcholinesterase that is predominant in mammalian brain and muscles (AChE(T)) possess a characteristic C-terminal tail (t) peptide. This t peptide allows their assembly into tetramers associated with the anchoring proteins ColQ and PRiMA. Although the t peptides of all vertebrate cholinesterases are remarkably similar and, in particular, contain seven strictly conserved aromatic residues, these enzymes differ in some of their oligomerization properties. To explore these differences, we studied human AChE (Aa) and BChE (Bb), and chimeras in which the t peptides (a and b) were exchanged (Ab and Ba). We found that secretion was increased by deletion of the t peptides, and that it was more efficient with a than with b. The patterns of oligomers were similar for Aa and Ab, as well as for Ba and Bb, indicating a predominant influence of the catalytic domains. However, addition of a cysteine within the aromatic-rich segment of the t peptides modified the oligomeric patterns: with a cysteine at position 19, the proportion of tetramers was markedly increased for Aa(S19C) and Ba(S19C), and to a lesser extent for Bb(N19C); the Ab(N19C) mutant produced all oligomeric forms, from monomers to hexamers. These results indicate that both the catalytic domains and the C-terminal t peptides contribute to the capacity of cholinesterases to form and secrete various oligomers. Sequence comparisons show that the differences between the t peptides of AChE and BChE are remarkably conserved among all vertebrates, suggesting that they reflect distinct functional adaptations.
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Affiliation(s)
- Dong Liang
- Laboratoire de Neurobiologie, CNRS UMR 8544, Ecole Normale Supérieure, Paris, France
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37
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Woods RR, Geyer BC, Mor TS. Hairy-root organ cultures for the production of human acetylcholinesterase. BMC Biotechnol 2008; 8:95. [PMID: 19105816 PMCID: PMC2648960 DOI: 10.1186/1472-6750-8-95] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2008] [Accepted: 12/23/2008] [Indexed: 12/16/2023] Open
Abstract
BACKGROUND Human cholinesterases can be used as a bioscavenger of organophosphate toxins used as pesticides and chemical warfare nerve agents. The practicality of this approach depends on the availability of the human enzymes, but because of inherent supply and regulatory constraints, a suitable production system is yet to be identified. RESULTS As a promising alternative, we report the creation of "hairy root" organ cultures derived via Agrobacterium rhizogenes-mediated transformation from human acetylcholinesterase-expressing transgenic Nicotiana benthamiana plants. Acetylcholinesterase-expressing hairy root cultures had a slower growth rate, reached to the stationary phase faster and grew to lower maximal densities as compared to wild type control cultures. Acetylcholinesterase accumulated to levels of up to 3.3% of total soluble protein, ~3 fold higher than the expression level observed in the parental plant. The enzyme was purified to electrophoretic homogeneity. Enzymatic properties were nearly identical to those of the transgenic plant-derived enzyme as well as to those of mammalian cell culture derived enzyme. Pharmacokinetic properties of the hairy-root culture derived enzyme demonstrated a biphasic clearing profile. We demonstrate that master banking of plant material is possible by storage at 4 degrees C for up to 5 months. CONCLUSION Our results support the feasibility of using plant organ cultures as a successful alternative to traditional transgenic plant and mammalian cell culture technologies.
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Affiliation(s)
- Ryan R Woods
- School of Life Sciences and The Biodesign Institute, P.O. Box 874501, Arizona State University, Tempe, AZ 85287-4501, USA
| | - Brian C Geyer
- School of Life Sciences and The Biodesign Institute, P.O. Box 874501, Arizona State University, Tempe, AZ 85287-4501, USA
| | - Tsafrir S Mor
- School of Life Sciences and The Biodesign Institute, P.O. Box 874501, Arizona State University, Tempe, AZ 85287-4501, USA
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Kim SK, Park JY, Koo BH, Lee JH, Kim HS, Choi WK, Shim I, Lee H, Hong MC, Shin MK, Min BI, Bae H. Adenoviral gene transfer of acetylcholinesterase T subunit in the hypothalamus potentiates electroacupuncture analgesia in rats. GENES BRAIN AND BEHAVIOR 2008; 8:174-80. [PMID: 19077179 DOI: 10.1111/j.1601-183x.2008.00459.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Our previous studies, using cDNA microarray and real-time reverse transcription-polymerase chain reaction, showed that acetylcholinesterase T subunit (AChET) gene was more abundantly expressed in the hypothalamus of the responder rats that were sensitive to electroacupuncture (EA) in the tail flick latency (TFL) test than in that of the non-responder rats that were insensitive to EA. In this study, we hypothesized that the expression of the AChET gene in the hypothalamus modulates EA analgesia in rats. To explore the hypothesis, we constructed an AChET-encoding adenovirus and a control virus expressing only green fluorescence protein, either of which was then injected into the hypothalamus of Sprague-Dawley rats. The hypothalamic activity of acetylcholinesterase was significantly higher in rats that were injected with the AChET virus than in rats that were injected with the control virus. The basal pain threshold measured by a TFL test was not changed by microinjection of AChET or control virus into the hypothalamus when EA treatment was not conducted. However, the analgesic effect of EA was significantly enhanced from 7 days after microinjection of the AChET virus into the hypothalamus but not after injection of the control virus. Furthermore, expression of the AChET in the hypothalamus did not affect body core temperature, body weight, motor function or learning and memory ability. Taken together, these results suggest that adenoviral expression of the AChET gene in the hypothalamus potentiates EA analgesia in rats without apparent side-effects.
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Affiliation(s)
- S K Kim
- College of Oriental Medicine, Kyung Hee University, Seoul, Korea
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39
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Buznikov GA, Nikitina LA, Seidler FJ, Slotkin TA, Bezuglov VV, Milosević I, Lazarević L, Rogac L, Ruzdijić S, Rakić LM. Amyloid precursor protein 96-110 and beta-amyloid 1-42 elicit developmental anomalies in sea urchin embryos and larvae that are alleviated by neurotransmitter analogs for acetylcholine, serotonin and cannabinoids. Neurotoxicol Teratol 2008; 30:503-9. [PMID: 18565728 PMCID: PMC2579926 DOI: 10.1016/j.ntt.2008.05.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2008] [Revised: 04/28/2008] [Accepted: 05/08/2008] [Indexed: 10/22/2022]
Abstract
Amyloid precursor protein (APP) is overexpressed in the developing brain and portions of its extracellular domain, especially amino acid residues 96-110, play an important role in neurite outgrowth and neural cell differentiation. In the current study, we evaluated the developmental abnormalities caused by administration of exogenous APP(96-110) in sea urchin embryos and larvae, which, like the developing mammalian brain, utilize acetylcholine and other neurotransmitters as morphogens; effects were compared to those of beta-amyloid 1-42 (Abeta42), the neurotoxic APP fragment contained within neurodegenerative plaques in Alzheimer's Disease. Although both peptides elicited dysmorphogenesis, Abeta42 was far more potent; in addition, whereas Abeta42 produced abnormalities at developmental stages ranging from early cleavage divisions to the late pluteus, APP(96-110) effects were restricted to the intermediate, mid-blastula stage. For both agents, anomalies were prevented or reduced by addition of lipid-permeable analogs of acetylcholine, serotonin or cannabinoids; physostigmine, a carbamate-derived cholinesterase inhibitor, was also effective. In contrast, agents that act on NMDA receptors (memantine) or alpha-adrenergic receptors (nicergoline), and that are therapeutic in Alzheimer's Disease, were themselves embryotoxic, as was tacrine, a cholinesterase inhibitor from a different chemical class than physostigmine. Protection was also provided by agents acting downstream from receptor-mediated events: increasing cyclic AMP with caffeine or isobutylmethylxanthine, or administering the antioxidant, a-tocopherol, were all partially effective. Our findings reinforce a role for APP in development and point to specific interactions with neurotransmitter systems that act as morphogens in developing sea urchins as well as in the mammalian brain.
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Affiliation(s)
- Gennady A Buznikov
- Department of Pharmacology & Cancer Biology, Duke University Medical Center, Durham, North Carolina 27710-3813, United States
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40
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Sussman JD, Argov Z, McKee D, Hazum E, Brawer S, Soreq H. Antisense treatment for myasthenia gravis: experience with monarsen. Ann N Y Acad Sci 2008; 1132:283-90. [PMID: 18567879 DOI: 10.1196/annals.1405.022] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Acetylcholinesterase pre-mRNA is susceptible to alternative splicing. Myasthenia gravis has been shown to be associated with the expression of the readthrough transcript (AChE-R), which, unlike the normal "synaptic" transcript (AChE-S) is not tethered to the post-synaptic membrane, but is a soluble monomer in the synaptic cleft. In rats with experimental autoimmune myasthenia gravis (EAMG), inhibition of production of AChE-R using antisense is associated with a significant reduction in synaptic expression of AChE-R mRNA and protein, with improved muscle strength and stamina and increased survival. Synaptic AChE does not appear to be significantly affected by the induction of EAMG or treatment with antisense to AChE-R. Monarsen (EN101) is a synthetic 20-base antisense oligodeoxynucleotide directed against the human AChE gene. It is modified to achieve stability for oral administration. Sixteen patients with seropositive myasthenia gravis who were responsive to pyridostigmine were withdrawn from it and treated with Monarsen. Fourteen patients experienced a clinically significant response. In some, the improvement was dramatic. Although the dose of pyridostigmine was not optimized before the study, the majority of responders achieved better Quantitative Myasthenia Gravis scores than on pyridostigmine. The response of an individual muscle group to Monarsen was related to the degree of deterioration following the withdrawal of pyridostigmine. Cholinergic side effects were conspicuous by their absence. Monarsen is now being investigated in a phase II study.
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Affiliation(s)
- Jon D Sussman
- Department of Neurology, Greater Manchester Neuroscience Centre, Hope Hospital, Stott Lane, Salford, Greater Manchester. UK. M6 8HD.
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41
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Old and new questions about cholinesterases. Chem Biol Interact 2008; 175:30-44. [DOI: 10.1016/j.cbi.2008.04.039] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2007] [Revised: 04/25/2008] [Accepted: 04/28/2008] [Indexed: 01/21/2023]
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Su W, Wu J, Ye WY, Zhang XJ. A monoclonal antibody against synaptic AChE: a useful tool for detecting apoptotic cells. Chem Biol Interact 2008; 175:101-7. [PMID: 18538755 DOI: 10.1016/j.cbi.2008.04.030] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2008] [Revised: 04/21/2008] [Accepted: 04/23/2008] [Indexed: 11/29/2022]
Abstract
The classical function of acetylcholinesterase (AChE) is to terminate synaptic transmission at cholinergic synapses by rapidly hydrolyzing the neurotransmitter acetylcholine (ACh). Non-classical functions of AChE involve accelerating the assembly of Abeta peptide into amyloid fibrils and participating in haematopoiesis and neurite growth. Although numerous antibodies have been raised against AChE, many researchers have questioned their reliability to identify the AChE in situ, especially with the regard to its non-classical roles. Researchers attended the Ninth International Meeting on Cholinesterase raised this question by showing different Western blot patterns of AChE detected by different Abs. Producing more effective and reliable Abs for measuring AChE in vivo or in situ has become an important issue in many scientific fields. In this paper, we introduce a monoclonal antibody raised against synaptic AChE that we identified by Western blot assays, immunofluorescent staining and immunoprecipitation of AChE, and mass spectrometry. Our results strongly demonstrate the specificity of our monoclonal antibody to recognize synaptic AChE; hence our antibody can be used as an effective tool to study the various functions of AChE. Since the apoptosis-related AChE was its synaptic form, our antibody can be used as a tool to detect apoptotic cells.
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Affiliation(s)
- Wei Su
- Laboratory of Molecular Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 YueYang Road, Shanghai, China
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Cohen J, Zimmerman G, Melamed-Book N, Friedman A, Dori A, Soreq H. Transgenic inactivation of acetylcholinesterase impairs homeostasis in mouse hippocampal granule cells. Hippocampus 2008; 18:182-92. [DOI: 10.1002/hipo.20381] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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Abou-Donia MB, Goldstein LB, Bullman S, Tu T, Khan WA, Dechkovskaia AM, Abdel-Rahman AA. Imidacloprid induces neurobehavioral deficits and increases expression of glial fibrillary acidic protein in the motor cortex and hippocampus in offspring rats following in utero exposure. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2008; 71:119-30. [PMID: 18080902 DOI: 10.1080/15287390701613140] [Citation(s) in RCA: 109] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Imidacloprid, a neonicotinoid, is one of the fastest growing insecticides in use worldwide because of its selectivity for insects. The potential for neurotoxicity following in utero exposure to imidacloprid is not known. Timed pregnant Sprague-Dawley rats (300-350 g) on d 9 of gestation were treated with a single intraperitoneal injection (i.p.) of imidacloprid (337 mg/kg, 0.75 x LD50, in corn oil). Control rats were treated with corn oil. On postnatal day (PND) 30, all male and female offspring were evaluated for (a) acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) activity, (b) ligand binding for nicotinic acetylcholine receptors (nAChR) and muscarinic acetylcholine receptors (m2 mAChR), (c) sensorimotor performance (inclined plane, beam-walking, and forepaw grip), and (d) pathological alterations in the brain (using cresyl violet and glial fibrillary acidic protein [GFAP] immunostaining). The offspring of treated mothers exhibited significant sensorimotor impairments at PND 30 during behavioral assessments. These changes were associated with increased AChE activity in the midbrain, cortex and brainstem (125-145% increase) and in plasma (125% increase). Ligand binding densities for [3H]cytosine for alpha4beta2 type nAchR did not show any significant change, whereas [3H]AFDX 384, a ligand for m2mAChR, was significantly increased in the cortex of offspring (120-155% increase) of imidacloprid-treated mothers. Histopathological evaluation using cresyl violet staining did not show any alteration in surviving neurons in various brain regions. On the other hand, there was a rise in GFAP immunostaining in motor cortex layer III, CA1, CA3, and the dentate gyrus subfield of the hippocampus of offspring of imidacloprid-treated mothers. The results indicate that gestational exposure to a single large, nonlethal, dose of imidacloprid produces significant neurobehavioral deficits and an increased expression of GFAP in several brain regions of the offspring on PND 30, corresponding to a human early adolescent age. These changes may have long-term adverse health effects in the offspring.
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Affiliation(s)
- Mohamed B Abou-Donia
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, North Carolina 27710, USA.
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Yang D, Howard A, Bruun D, Ajua-Alemanj M, Pickart C, Lein PJ. Chlorpyrifos and chlorpyrifos-oxon inhibit axonal growth by interfering with the morphogenic activity of acetylcholinesterase. Toxicol Appl Pharmacol 2007; 228:32-41. [PMID: 18076960 DOI: 10.1016/j.taap.2007.11.005] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2007] [Revised: 10/26/2007] [Accepted: 11/07/2007] [Indexed: 01/08/2023]
Abstract
A primary role of acetylcholinesterase (AChE) is regulation of cholinergic neurotransmission by hydrolysis of synaptic acetylcholine. In the developing nervous system, however, AChE also functions as a morphogenic factor to promote axonal growth. This raises the question of whether organophosphorus pesticides (OPs) that are known to selectively bind to and inactivate the enzymatic function of AChE also interfere with its morphogenic function to perturb axonogenesis. To test this hypothesis, we exposed primary cultures of sensory neurons derived from embryonic rat dorsal root ganglia (DRG) to chlorpyrifos (CPF) or its oxon metabolite (CPFO). Both OPs significantly decreased axonal length at concentrations that had no effect on cell viability, protein synthesis or the enzymatic activity of AChE. Comparative analyses of the effects of CPF and CPFO on axonal growth in DRG neurons cultured from AChE nullizygous (AChE -/-) versus wild type (AChE +/+) mice indicated that while these OPs inhibited axonal growth in AChE+/+ DRG neurons, they had no effect on axonal growth in AChE -/- DRG neurons. However, transfection of AChE -/- DRG neurons with cDNA encoding full-length AChE restored the wild type response to the axon inhibitory effects of OPs. These data indicate that inhibition of axonal growth by OPs requires AChE, but the mechanism involves inhibition of the morphogenic rather than enzymatic activity of AChE. These findings suggest a novel mechanism for explaining not only the functional deficits observed in children and animals following developmental exposure to OPs, but also the increased vulnerability of the developing nervous system to OPs.
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Affiliation(s)
- Dongren Yang
- Center for Research on Occupational and Environmental Toxicology, Oregon Health & Science University, Portland, OR 97239, USA
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Abstract
The entorhinal cortex-hippocampus complex is believed to be the site of origin of seizure activity in the majority of patients with temporal lobe epilepsy (TLE). Both these regions are enriched with cholinergic innervation, which plays a key role in the normal control of neuronal excitability and in higher cognitive processes. In TLE, anatomical and functional changes occur in all cellular components of the local neural circuit. Thus, while it is not surprising that cholinergic functions are altered in the epileptic temporal lobe, the exact nature and role of these changes in the pathogenesis of the disease are not known. In this report, we summarize the scientific background and experimental data supporting a "cholinergic hypothesis of TLE." We conclude that while the exact role of cholinergic dysfunction in TLE is not known, there is a firm basis for suggesting that changes in the expression of key cholinergic proteins-and the associated cholinergic dysfunction-are key factors in the basic mechanisms underlying TLE.
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Affiliation(s)
- Alon Friedman
- Department of Physiology, Soroka University Medical Center, Ben-Gurion University of the Negev, Beer-Sheva, Israel
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Zimmermann M, Grösgen S, Westwell MS, Greenfield SA. Selective enhancement of the activity of C-terminally truncated, but not intact, acetylcholinesterase. J Neurochem 2007; 104:221-32. [PMID: 17986217 DOI: 10.1111/j.1471-4159.2007.05045.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Acetylcholinesterase (AChE) is one of the fastest enzymes approaching the catalytic limit of enzyme activity. The enzyme is involved in the terminal breakdown of the neurotransmitter acetylcholine, but non-enzymatic roles have also been described for the entire AChE molecule and its isolated C-terminal sequences. These non-cholinergic functions have been attributed to both the developmental and degenerative situation: the major form of AChE present in these conditions is monomeric. Moreover, AChE has been shown to lose its typical characteristic of substrate inhibition in both development and degeneration. This study characterizes a form of AChE truncated after amino acid 548 (T548-AChE), whose truncation site is homologue to that of a physiological form of T-AChE detected in fetal bovine serum that has lost its C-terminal moiety supposedly due to proteolytic cleavage. Peptide sequences covered by this C-terminal sequence have been shown to be crucially involved in both developmental and degenerative mechanisms in vitro. Numerous studies have addressed the structure-function relationship of the AChE C-terminus with T548-AChE representing one of the most frequently studied forms of truncated AChE. In this study, we provide new insight into the understanding of the functional characteristics that T548-AChE acquires in solution: T548-AChE is incubated with agents of varying net charge and molecular weight. Together with kinetic studies and an analysis of different molecular forms and aggregation states of T548-AChE, we show that the enzymatic activity of T548-AChE, an enzyme verging at its catalytic limit is, nonetheless, apparently enhanced by up to 800%. We demonstrate, first, how the activity of T548-AChE can be enhanced through agents that contain highly positive charged moieties. Moreover, the un-competitive mechanism of activity enhancement most likely involves the peripheral anionic site of AChE that is reflected in delayed substrate inhibition being observed for activity enhanced T548-AChE. The data provides evidence towards a mechanistic and functional link between the form of AChE unique to both development and degeneration and a C-terminal peptide of T-AChE acting under those conditions.
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Affiliation(s)
- Martina Zimmermann
- The Institute for the Future of the Mind, Department of Pharmacology, University of Oxford, Mansfield Road, Oxford, UK.
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Badiou A, Brunet JL, Belzunces LP. Existence of two membrane-bound acetylcholinesterases in the honey bee head. ARCHIVES OF INSECT BIOCHEMISTRY AND PHYSIOLOGY 2007; 66:122-134. [PMID: 17966129 DOI: 10.1002/arch.20204] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Two acetylcholinesterase (EC 3.1.1.7) membrane forms AChE(m1) and AChE(m2), have been characterised in the honey bee head. They can be differentiated by their ionic properties: AChE(m1) is eluted at 220 mM NaCl whereas AChE(m2) is eluted at 350 mM NaCl in anion exchange chromatography. They also present different thermal stabilities. Previous processing such as sedimentation, phase separation, and extraction procedures do not affect the presence of the two forms. Unlike AChE(m1), AChE(m2) presents reversible chromatographic elution properties, with a shift between 350 to 220 mM NaCl, depending on detergent conditions. Purification by affinity chromatography does not abolish the shift of the AChE(m2) elution. The similar chromatographic behaviour of soluble AChE strongly suggests that the occurrence of the two membrane forms is not due to the membrane anchor. The two forms have similar sensitivities to eserine and BW284C51. They exhibit similar electrophoretic mobilities and present molecular masses of 66 kDa in SDS-PAGE and a sensitivity to phosphatidylinositol-specific phospholipase C in non-denaturing conditions, thus revealing the presence of a glycosyl-phosphatidylinositol anchor. We assume that bee AChE occurs in two distinct conformational states whose AChE(m2) apparent state is reversibly modulated by the Triton X-100 detergent into AChE(m1).
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Affiliation(s)
- Alexandra Badiou
- INRA, Laboratoire de Toxicologie Environnementale, UMR INRA-UAPV 406 Ecologie des Invertébrés, Avignon, France.
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Evron T, Geyer BC, Cherni I, Muralidharan M, Kilbourne J, Fletcher SP, Soreq H, Mor TS. Plant-derived human acetylcholinesterase-R provides protection from lethal organophosphate poisoning and its chronic aftermath. FASEB J 2007; 21:2961-9. [PMID: 17475919 PMCID: PMC2766558 DOI: 10.1096/fj.07-8112com] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Therapeutically valuable proteins are often rare and/or unstable in their natural context, calling for production solutions in heterologous systems. A relevant example is that of the stress-induced, normally rare, and naturally unstable "read-through" human acetylcholinesterase variant, AChE-R. AChE-R shares its active site with the synaptic AChE-S variant, which is the target of poisonous organophosphate anticholinesterase insecticides such as the parathion metabolite paraoxon. Inherent AChE-R overproduction under organophosphate intoxication confers both short-term protection (as a bioscavenger) and long-term neuromuscular damages (as a regulator). Here we report the purification, characterization, and testing of human, endoplasmic reticulum-retained AChE-R(ER) produced from plant-optimized cDNA in Nicotiana benthamiana plants. AChE-R(ER) purified to homogeneity showed indistinguishable biochemical properties, with IC50 = 10(-7) M for the organophosphate paraoxon, similar to mammalian cell culture-derived AChE. In vivo titration showed dose-dependent protection by intravenously injected AChE-R(ER) of FVB/N male mice challenged with a lethal dose of paraoxon, with complete elimination of short-term clinical symptoms at near molar equivalence. By 10 days postexposure, AChE-R prophylaxis markedly limited postexposure increases in plasma murine AChE-R levels while minimizing the organophosphate-induced neuromuscular junction dismorphology. Our findings present plant-produced AChE-R(ER) as a bimodal agent, conferring both short- and long-term protection from organophosphate intoxication.
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Affiliation(s)
- Tama Evron
- The Department of Biological Chemistry, The Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Brian C. Geyer
- School of Life Sciences and The Biodesign Institute, Arizona State University, Tempe, Arizona, USA
| | - Irene Cherni
- School of Life Sciences and The Biodesign Institute, Arizona State University, Tempe, Arizona, USA
| | - Mrinalini Muralidharan
- School of Life Sciences and The Biodesign Institute, Arizona State University, Tempe, Arizona, USA
| | - Jacquelyn Kilbourne
- School of Life Sciences and The Biodesign Institute, Arizona State University, Tempe, Arizona, USA
| | - Samuel P. Fletcher
- School of Life Sciences and The Biodesign Institute, Arizona State University, Tempe, Arizona, USA
| | - Hermona Soreq
- The Department of Biological Chemistry, The Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Tsafrir S. Mor
- School of Life Sciences and The Biodesign Institute, Arizona State University, Tempe, Arizona, USA
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Translational control of recombinant human acetylcholinesterase accumulation in plants. BMC Biotechnol 2007; 7:27. [PMID: 17537261 PMCID: PMC1913049 DOI: 10.1186/1472-6750-7-27] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2007] [Accepted: 05/30/2007] [Indexed: 11/10/2022] Open
Abstract
Background Codon usage differences are known to regulate the levels of gene expression in a species-specific manner, with the primary factors often cited to be mRNA processing and accumulation. We have challenged this conclusion by expressing the human acetylcholinesterase coding sequence in transgenic plants in its native GC-rich sequence and compared to a matched sequence with (dicotyledonous) plant-optimized codon usage and a lower GC content. Results We demonstrate a 5 to 10 fold increase in accumulation levels of the "synaptic" splice variant of human acetylcholinesterase in Nicotiana benthamiana plants expressing the optimized gene as compared to the native human sequence. Both transient expression assays and stable transformants demonstrated conspicuously increased accumulation levels. Importantly, we find that the increase is not a result of increased levels of acetylcholinesterase mRNA, but rather its facilitated translation, possibly due to the reduced energy required to unfold the sequence-optimized mRNA. Conclusion Our findings demonstrate that codon usage differences may regulate gene expression at different levels and anticipate translational control of acetylcholinesterase gene expression in its native mammalian host as well.
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