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Gorzi A, Jafari F, Allahmoradi N, Rahmani A, Krause Neto W. Training Intensity, Not Duration, May Be Key to Upregulating Presynaptic Proteins of Calcium Dynamics and Calcium-Dependent Exocytosis in Fast- and Slow-Twitch Skeletal Muscles, in Addition to Maintaining Performance After Detraining. Mol Neurobiol 2021; 58:6670-6683. [PMID: 34608606 DOI: 10.1007/s12035-021-02576-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 09/22/2021] [Indexed: 10/20/2022]
Abstract
Neuromuscular adaptations are essential for improving athletic performance. However, little is known about the effect of different endurance training protocols and their subsequent detraining on the gene expression of critical factors for neuromuscular synaptic transmission. Therefore, this study investigated the effects of endurance training (high-intensity interval training [HIIT], continuous [cEND], mixed interval [Mix], and all protocols combined [Comb]) and detraining on performance and gene expression (GE) of the alpha-1a, synaptotagmin II (Syt-II), synaptobrevin II (Vamp2), and acetylcholinesterase (AChE) in the gastrocnemius and soleus of Wistar rats. Eighty rodents were randomly divided into control, HIIT, cEND, Mix, Comb, and detraining groups. The rodents trained for 6 weeks (5 × /week), followed by 2 weeks of detraining. Performance improved in all training groups and decreased following detraining (p < 0.05), except HIIT. In the gastrocnemius, alpha-1a GE was upregulated in the Mix. Syt-II and AChE GE were upregulated in HIIT, Mix, and Comb. Vamp2 GE was upregulated in all groups. In the soleus, alpha-1a GE was upregulated in HIIT, Mix, and Comb. Syt-II and Vamp2 GE were upregulated in all groups. AChE GE was upregulated in cEND, Mix, and Comb. Detraining downregulated mostly the gene expression in the skeletal muscles. We conclude that training intensity appears to be a key factor for the upregulation of molecules involved in neuromuscular synaptic transmission. Such changes occur to be involved in improving running performance. On the other hand, detraining negatively affects synaptic transmission and performance.
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Affiliation(s)
- Ali Gorzi
- Department of Sport Sciences, University of Zanjan, Zanjan, Iran.
| | - Fatemeh Jafari
- Department of Sport Sciences, University of Zanjan, Zanjan, Iran
| | | | - Ahmad Rahmani
- Department of Sport Sciences, University of Zanjan, Zanjan, Iran
| | - Walter Krause Neto
- Department of Physical Education, Laboratory of Morphoquantitative Studies and Immunohistochemistry, São Judas Tadeu University, 546 - Mooca Unit, P.O box 03166-000, São Paulo, SP, Brazil.
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Luo X, Lauwers M, Layer PG, Wen C. Non-neuronal Role of Acetylcholinesterase in Bone Development and Degeneration. Front Cell Dev Biol 2021; 8:620543. [PMID: 33585459 PMCID: PMC7876280 DOI: 10.3389/fcell.2020.620543] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 12/28/2020] [Indexed: 12/14/2022] Open
Abstract
Acetylcholinesterase (AChE), an enzyme catalyzing the degradation of acetylcholine, plays an important suppressive role in the cholinergic regulation by terminating the action of acetylcholine. The expression of acetylcholinesterase and other cholinergic components is not restricted to only brain and nerve tissues but can also be found in non-neuronal tissues like the immune system and bone tissue. Primary identification of these components has been achieved. However, the information about their specific functions and underlying molecular mechanisms in bone remains scattered. Here, the physiological process of bone development, homeostasis, and degeneration are introduced. Next, the cholinergic system and its expression in bone tissue is documented. Among them, special attention goes to AChE, as the structure of this enzyme suggests diverse binding affinities, enabled by a peripheral site and a catalytic site. The peripheral site supports the non-enzymatic function of AChE in non-neuronal systems. Based on recent studies, the non-neuronal roles of acetylcholinesterase, both enzymatically and non-enzymatically, in bone development, homeostasis and degeneration are summarized briefly together with potential mechanisms to support these functions. We conclude that AChE may be a potential therapeutic target for bone diseases like osteoporosis.
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Affiliation(s)
- Xiaohe Luo
- Department of Biomedical Engineering, Faculty of Engineering, The Hong Kong Polytechnic University, Hong Kong, China
| | - Marianne Lauwers
- Department of Biomedical Engineering, Faculty of Engineering, The Hong Kong Polytechnic University, Hong Kong, China
| | - Paul G Layer
- Developmental Biology and Neurogenetics, Technische Universität Darmstadt, Darmstadt, Germany
| | - Chunyi Wen
- Department of Biomedical Engineering, Faculty of Engineering, The Hong Kong Polytechnic University, Hong Kong, China
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Wu Q, Bai P, Xia Y, Lai QWS, Guo MSS, Dai K, Zheng Z, Ling CSJ, Dong TTX, Pi R, Tsim KWK. Solar light induces expression of acetylcholinesterase in skin keratinocytes: Signalling mediated by activator protein 1 transcription factor. Neurochem Int 2020; 141:104861. [PMID: 33038610 DOI: 10.1016/j.neuint.2020.104861] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 09/20/2020] [Accepted: 09/30/2020] [Indexed: 11/24/2022]
Abstract
Acetylcholinesterase (AChE) hydrolyses acetylcholine to choline and acetate, playing an important role in terminating the neurotransmission in brain and muscle. Recently, the non-neuronal functions of AChE have been proposed in different tissues, in which there are various factors to regulate the expression of AChE. In mammalian skin, AChE was identified in melanocytes and keratinocytes. Our previous study has indicated that AChE in keratinocyte affects the process of solar light-induced skin pigmentation; however, the expression of AChE in keratinocytes in responding to sunlight remains unknown. Here, we provided several lines of evidence to support a notion that AChE could be upregulated at transcriptional and translational levels in keratinocytes when exposed to solar light. The light-mediated AChE expression was triggered by Ca2+, supported by an induction of Ca2+ ionophore A23187 and a blockage by Ca2+ chelator BAPTA-AM. In addition, this increase on AChE transcriptional expression was eliminated by mutagenesis on the activating protein 1 (AP1) site in ACHE gene. Hence, the solar light-induced AChE expression is mediated by Ca2+ signalling through AP1 site. This finding supports the role of solar light in affecting the cholinergic system in skin cells, and which may further influence the dermatological function.
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Affiliation(s)
- Qiyun Wu
- Shenzhen Key Laboratory of Edible and Medicinal Bioresources, Shenzhen Research Institute, Shenzhen, 518000, China; Division of Life Science and Centre for Chinese Medicine, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China
| | - Panzhu Bai
- Division of Life Science and Centre for Chinese Medicine, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China
| | - Yingjie Xia
- Division of Life Science and Centre for Chinese Medicine, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China
| | - Queenie W S Lai
- Division of Life Science and Centre for Chinese Medicine, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China
| | - Maggie S S Guo
- Division of Life Science and Centre for Chinese Medicine, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China
| | - Kun Dai
- Division of Life Science and Centre for Chinese Medicine, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China
| | - Zhongyu Zheng
- Division of Life Science and Centre for Chinese Medicine, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China
| | - Christine S J Ling
- Division of Life Science and Centre for Chinese Medicine, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China
| | - Tina T X Dong
- Shenzhen Key Laboratory of Edible and Medicinal Bioresources, Shenzhen Research Institute, Shenzhen, 518000, China; Division of Life Science and Centre for Chinese Medicine, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China
| | - Rongbiao Pi
- School of Medicine, Sun Yat-Sen University, Guangzhou, 518000, China
| | - Karl W K Tsim
- Shenzhen Key Laboratory of Edible and Medicinal Bioresources, Shenzhen Research Institute, Shenzhen, 518000, China; Division of Life Science and Centre for Chinese Medicine, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China.
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4
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Liu QP, Zhang X, Qin YZ, Yi JL, Li JM. Acetylcholinesterase inhibition ameliorates retinal neovascularization and glial activation in oxygen-induced retinopathy. Int J Ophthalmol 2020; 13:1361-1367. [PMID: 32953572 DOI: 10.18240/ijo.2020.09.04] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Accepted: 05/25/2020] [Indexed: 02/07/2023] Open
Abstract
AIM To investigate whether inhibition of acetylcholinesterase (AChE) by donepezil ameliorate aberrant retinal neovascularization (RNV) and abnormal glial activation in oxygen-induced retinopathy (OIR). METHODS A mouse model of RNV was induced in postnatal day 7 (P7) mice by exposure to 75% oxygen. Donepezil was administrated to P12 mice by intraperitoneal injection. Expression and localization of AChE in mouse retinas were determined by immunofluorescence. RNV was evaluated by paraffin sectioning and hematoxylin and eosin (HE) staining. Activation of retinal Müller glial cells were examined by immunoblot of glial fibrillary acidic protein (GFAP). rMC-1, a retinal Müller cell line, was used for in vitro study. Expression of hypoxia-induced factor 1α (HIF-1α) and vascular endothelial growth factor (VEGF) were determined by Western-blot analysis, enzyme-linked immunosorbent assay (ELISA) or immunostaining. RESULTS Aberrant RNV and glial activation was observed after OIR. Of note, retinal AChE was mainly expressed by retinal Müller glial cells and markedly increased in OIR mice. Systemic administration of donepezil significantly reduced RNV and abnormal glial activation in mice with OIR. Moreover, ischemia-induced HIF-1α accumulation and VEGF upregulation in OIR mouse retinas and cultured rMC-1 were significantly inhibited by donepezil intervention. CONCLUSION AchE is implicated in RNV with OIR. Inhibition of AChE by donepeizl is likely to be a potential therapeutic approach for retinal neovascular diseases.
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Affiliation(s)
- Qiu-Ping Liu
- Affiliated Eye Hospital of Nanchang University, Nanchang 330006, Jiangxi Province, China
| | - Xian Zhang
- Affiliated Eye Hospital of Nanchang University, Nanchang 330006, Jiangxi Province, China
| | - Ya-Zhou Qin
- Department of Ophthalmology, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710061, Shaanxi Province, China
| | - Jing-Lin Yi
- Affiliated Eye Hospital of Nanchang University, Nanchang 330006, Jiangxi Province, China
| | - Jing-Ming Li
- Department of Ophthalmology, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an 710061, Shaanxi Province, China
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The NMJ as a model synapse: New perspectives on formation, synaptic transmission and maintenance: Acetylcholinesterase at the neuromuscular junction. Neurosci Lett 2020; 735:135157. [PMID: 32540360 DOI: 10.1016/j.neulet.2020.135157] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 06/10/2020] [Accepted: 06/11/2020] [Indexed: 12/28/2022]
Abstract
Acetylcholinesterase (AChE) is an essential enzymatic component of the neuromuscular junction where it is responsible for terminating neurotransmission by the cholinergic motor neurons. The enzyme at the neuromuscular junction (NMJ) is contributed primarily by the skeletal muscle where it is produced at higher levels in the post-synaptic region of the fibers. The major form of AChE at the NMJ is a large asymmetric form consisting of three tetramers covalently attached to a three-stranded collagen-like tail which is responsible for anchoring it to the synaptic basal lamina. Its location and expression is regulated to a large extent by the motor neurons and occurs at the transcriptional, translational and post-translational levels. While its expression can be quite rapid in tissue cultured cells, its half-life in vivo appears to be quite long, about three weeks, although more rapidly turning over pools have been described. Finally the essential nature of this enzyme is underscored by the fact that no naturally occurring null mutations of the catalytic subunit have been described in higher organisms and the few dozen humans carrying mutations in the collagen tail responsible for anchoring the enzyme at the NMJ are severely affected.
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Targeted sequencing of linkage region in Dominican families implicates PRIMA1 and the SPATA7-PTPN21-ZC3H14-EML5-TTC8 locus in carotid-intima media thickness and atherosclerotic events. Sci Rep 2019; 9:11621. [PMID: 31406157 PMCID: PMC6691113 DOI: 10.1038/s41598-019-48186-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Accepted: 07/29/2019] [Indexed: 11/22/2022] Open
Abstract
Carotid intima-media thickness (cIMT) is a subclinical marker for atherosclerosis. Previously, we reported a quantitative trait locus (QTL) for total cIMT on chromosome 14q and identified PRiMA1, FOXN3 and CCDC88C as candidate genes using a common variants (CVs)-based approach. Herein, we further evaluated the genetic contribution of the QTL to cIMT by resequencing. We sequenced all exons within the QTL and genomic regions of PRiMA1, FOXN3 and CCDC88C in Dominican families with evidence for linkage to the QTL. Unrelated Dominicans from the Northern Manhattan Study (NOMAS) were used for validation. Single-variant-based and gene-based analyses were performed for CVs and rare variants (RVs). The strongest evidence for association with CVs was found in PRiMA1 (p = 8.2 × 10−5 in families, p = 0.01 in NOMAS at rs12587586), and in the five-gene cluster SPATA7-PTPN21-ZC3H14-EML5-TTC8 locus (p = 1.3 × 10−4 in families, p = 0.01 in NOMAS at rs2274736). No evidence for association with RVs was found in PRiMA1. The top marker from previous study in PRiMA1 (rs7152362) was associated with fewer atherosclerotic events (OR = 0.67; p = 0.02 in NOMAS) and smaller cIMT (β = −0.58, p = 2.8 × 10−4 in Family). Within the five-gene cluster, evidence for association was found for exonic RVs (p = 0.02 in families, p = 0.28 in NOMAS), which was enriched among RVs with higher functional potentials (p = 0.05 in NOMAS for RVs in the top functional tertile). In summary, targeted resequencing provided validation and novel insights into the genetic architecture of cIMT, suggesting stronger effects for RVs with higher functional potentials. Furthermore, our data support the clinical relevance of CVs associated with subclinical atherosclerosis.
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Grassi F, Fucile S. Calcium influx through muscle nAChR-channels: One route, multiple roles. Neuroscience 2019; 439:117-124. [PMID: 30999028 DOI: 10.1016/j.neuroscience.2019.04.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Revised: 04/01/2019] [Accepted: 04/04/2019] [Indexed: 01/31/2023]
Abstract
Although Ca2+ influx through muscle nAChR-channels has been described over the past 40 years, its functions remain still poorly understood. In this review we suggest possible roles of Ca2+ entry at all stages of muscle development, summarizing the evidence present in literature. nAChRs are expressed in myoblasts prior to fusion, and can be activated in the absence of an ACh-releasing nerve terminal, with Ca2+ influx likely contributing to regulate cell fusion. Upon establishment of nerve-muscle contact, Ca2+ influx contributes to orchestrate the signaling required for the correct formation of the neuromuscular junction. Finally, in the mature synapse, Ca2+ entry through postsynaptic nAChR-channels - highly Ca2+ permeable, in particular in humans - acts on K+ and Na+ channels to shape endplate excitability. However, when genetic defects cause excessive channel activation, Ca2+ influx becomes toxic and causes endplate myopathy. Throughout the review, we highlight how Ricardo Miledi has contributed to construct this whole body of knowledge, from the initial description of Ca2+ permeability of endplate nAChR channels, to the rationale for the treatment of endplate excitotoxic damage under pathological conditions. This article is part of a Special Issue entitled: SI: Honoring Ricardo Miledi - outstanding neuroscientist of XX-XXI centuries.
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Affiliation(s)
- Francesca Grassi
- Department of Physiology and Pharmacology, Sapienza University, piazzale Aldo Moro 5, 00185, Rome, Italy.
| | - Sergio Fucile
- Department of Physiology and Pharmacology, Sapienza University, piazzale Aldo Moro 5, 00185, Rome, Italy; IRCCS Neuromed, Viale dell'Elettronica, 86077, Pozzilli, Italy
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8
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Kroth A, Mackedanz V, Matté C, Wyse ATS, Ribeiro MFM, Partata WA. Effect of Sciatic Nerve Transection on acetylcholinesterase activity in spinal cord and skeletal muscles of the bullfrog Lithobates catesbeianus. BRAZ J BIOL 2017; 78:217-223. [PMID: 28977043 DOI: 10.1590/1519-6984.03016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2016] [Accepted: 10/05/2016] [Indexed: 11/21/2022] Open
Abstract
Sciatic nerve transection (SNT), a model for studying neuropathic pain, mimics the clinical symptoms of "phantom limb", a pain condition that arises in humans after amputation or transverse spinal lesions. In some vertebrate tissues, this condition decreases acetylcholinesterase (AChE) activity, the enzyme responsible for fast hydrolysis of released acetylcholine in cholinergic synapses. In spinal cord of frog Rana pipiens, this enzyme's activity was not significantly changed in the first days following ventral root transection, another model for studying neuropathic pain. An answerable question is whether SNT decreases AChE activity in spinal cord of frog Lithobates catesbeianus, a species that has been used as a model for studying SNT-induced neuropathic pain. Since each animal model has been created with a specific methodology, and the findings tend to vary widely with slight changes in the method used to induce pain, our study assessed AChE activity 3 and 10 days after complete SNT in lumbosacral spinal cord of adult male bullfrog Lithobates catesbeianus. Because there are time scale differences of motor endplate maturation in rat skeletal muscles, our study also measured the AChE activity in bullfrog tibial posticus (a postural muscle) and gastrocnemius (a typical skeletal muscle that is frequently used to study the motor system) muscles. AChE activity did not show significant changes 3 and 10 days following SNT in spinal cord. Also, no significant change occurred in AChE activity in tibial posticus and gastrocnemius muscles at day 3. However, a significant decrease was found at day 10, with reductions of 18% and 20% in tibial posticus and gastrocnemius, respectively. At present we cannot explain this change in AChE activity. While temporally different, the direction of the change was similar to that described for rats. This similarity indicates that bullfrog is a valid model for investigating AChE activity following SNT.
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Affiliation(s)
- A Kroth
- Universidade do Oeste de Santa Catarina, Joaçaba, SC, Brazil
| | - V Mackedanz
- Departamento de Bioquimica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - C Matté
- Departamento de Bioquimica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - A T S Wyse
- Departamento de Bioquimica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - M F M Ribeiro
- Departamento de Fisiologia, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - W A Partata
- Departamento de Fisiologia, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
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Xu ML, Bi CWC, Liu EYL, Dong TTX, Tsim KWK. Wnt3a induces the expression of acetylcholinesterase during osteoblast differentiation via the Runx2 transcription factor. J Biol Chem 2017; 292:12667-12678. [PMID: 28607150 DOI: 10.1074/jbc.m117.777581] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Revised: 06/08/2017] [Indexed: 12/14/2022] Open
Abstract
Acetylcholinesterase (AChE) hydrolyzes acetylcholine to terminate cholinergic transmission in neurons. Apart from this AChE activity, emerging evidence suggests that AChE could also function in other, non-neuronal cells. For instance, in bone, AChE exists as a proline-rich membrane anchor (PRiMA)-linked globular form in osteoblasts, in which it is proposed to play a noncholinergic role in differentiation. However, this hypothesis is untested. Here, we found that in cultured rat osteoblasts, AChE expression was increased in parallel with osteoblastic differentiation. Because several lines of evidence indicate that AChE activity in osteoblast could be triggered by Wnt/β-catenin signaling, we added recombinant human Wnt3a to cultured osteoblasts and found that this addition induced expression of the ACHE gene and protein product. This Wnt3a-induced AChE expression was blocked by the Wnt-signaling inhibitor Dickkopf protein-1 (DKK-1). We hypothesized that the Runt-related transcription factor 2 (Runx2), a downstream transcription factor in Wnt/β-catenin signaling, is involved in AChE regulation in osteoblasts, confirmed by the identification of a Runx2-binding site in the ACHE gene promoter, further corroborated by ChIP. Of note, Runx2 overexpression in osteoblasts induced AChE expression and activity of the ACHE promoter tagged with the luciferase gene. Moreover, deletion of the Runx2-binding site in the ACHE promoter reduced its activity during osteoblastic differentiation, and addition of 5-azacytidine and trichostatin A to differentiating osteoblasts affected AChE expression, suggesting epigenetic regulation of the ACHE gene. We conclude that AChE plays a role in osteoblastic differentiation and is regulated by both Wnt3a and Runx2.
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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, Hong Kong, China; HKUST Shenzhen Research Institute, Hi-Tech Park, Nanshan, Shenzhen 518000, Guangdong Province, China
| | - Cathy W C Bi
- Division of Life Science and Center for Chinese Medicine, The Hong Kong University of Science and Technology, Hong Kong, China; HKUST Shenzhen Research Institute, Hi-Tech Park, Nanshan, Shenzhen 518000, Guangdong Province, China
| | - Etta Y L Liu
- Division of Life Science and Center for Chinese Medicine, The Hong Kong University of Science and Technology, Hong Kong, China; HKUST Shenzhen Research Institute, Hi-Tech Park, Nanshan, Shenzhen 518000, Guangdong Province, China
| | - Tina T X Dong
- Division of Life Science and Center for Chinese Medicine, The Hong Kong University of Science and Technology, Hong Kong, China; HKUST Shenzhen Research Institute, Hi-Tech Park, Nanshan, Shenzhen 518000, Guangdong Province, China
| | - Karl W K Tsim
- Division of Life Science and Center for Chinese Medicine, The Hong Kong University of Science and Technology, Hong Kong, China; HKUST Shenzhen Research Institute, Hi-Tech Park, Nanshan, Shenzhen 518000, Guangdong Province, China.
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10
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Exercise modulates synaptic acetylcholinesterase at neuromuscular junctions. Neuroscience 2016; 319:221-32. [DOI: 10.1016/j.neuroscience.2016.01.044] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Revised: 12/31/2015] [Accepted: 01/19/2016] [Indexed: 11/22/2022]
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11
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Lau KM, Gong AGW, Xu ML, Lam CTW, Zhang LML, Bi CWC, Cui D, Cheng AWM, Dong TTX, Tsim KWK, Lin H. Transcriptional activity of acetylcholinesterase gene is regulated by DNA methylation during C2C12 myogenesis. Brain Res 2016; 1642:114-123. [PMID: 27021952 DOI: 10.1016/j.brainres.2016.03.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Revised: 02/25/2016] [Accepted: 03/15/2016] [Indexed: 12/26/2022]
Abstract
The expression of acetylcholinesterase (AChE), an enzyme hydrolyzes neurotransmitter acetylcholine at vertebrate neuromuscular junction, is regulated during myogenesis, indicating the significance of muscle intrinsic factors in controlling the enzyme expression. DNA methylation is essential for temporal control of myogenic gene expression during myogenesis; however, its role in AChE regulation is not known. The promoter of vertebrate ACHE gene carries highly conserved CG-rich regions, implying its likeliness to be methylated for epigenetic regulation. A DNA methyltransferase inhibitor, 5-azacytidine (5-Aza), was applied onto C2C12 cells throughout the myotube formation. When DNA methylation was inhibited, the promoter activity, transcript expression and enzymatic activity of AChE were markedly increased after day 3 of differentiation, which indicated the putative role of DNA methylation. By bisulfite pyrosequencing, the overall methylation rate was found to peak at day 3 during C2C12 cell differentiation; a SP1 site located at -1826bp upstream of mouse ACHE gene was revealed to be heavily methylated. The involvement of transcriptional factor SP1 in epigenetic regulation of AChE was illustrated here: (i) the SP1-driven transcriptional activity was increased in 5-Aza-treated C2C12 culture; (ii) the binding of SP1 onto the SP1 site of ACHE gene was fully blocked by the DNA methylation; and (iii) the sequence flanking SP1 sites of ACHE gene was precipitated by chromatin immuno-precipitation assay. The findings suggested the role of DNA methylation on AChE transcriptional regulation and provided insight in elucidating the DNA methylation-mediated regulatory mechanism on AChE expression during muscle differentiation.
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Affiliation(s)
- Kei M Lau
- Division of Life Science and Center of 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 of Chinese Medicine, The Hong Kong University of Science and Technology, Clear Water Bay Road, Hong Kong, China
| | - Miranda L Xu
- Division of Life Science and Center of Chinese Medicine, The Hong Kong University of Science and Technology, Clear Water Bay Road, Hong Kong, China
| | - Candy T W Lam
- Division of Life Science and Center of Chinese Medicine, The Hong Kong University of Science and Technology, Clear Water Bay Road, Hong Kong, China
| | - Laura M L Zhang
- Division of Life Science and Center of 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 of Chinese Medicine, The Hong Kong University of Science and Technology, Clear Water Bay Road, Hong Kong, China
| | - D Cui
- Division of Life Science and Center of 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 of Chinese Medicine, The Hong Kong University of Science and Technology, Clear Water Bay Road, Hong Kong, China
| | - Tina T X Dong
- Division of Life Science and Center of 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 of 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 of Chinese Medicine, The Hong Kong University of Science and Technology, Clear Water Bay Road, Hong Kong, China.
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12
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García-Ayllón MS, Campanari ML, Montenegro MF, Cuchillo-Ibáñez I, Belbin O, Lleó A, Tsim K, Vidal CJ, Sáez-Valero J. Presenilin-1 influences processing of the acetylcholinesterase membrane anchor PRiMA. Neurobiol Aging 2014; 35:1526-36. [PMID: 24612677 DOI: 10.1016/j.neurobiolaging.2014.01.147] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2013] [Revised: 01/26/2014] [Accepted: 01/30/2014] [Indexed: 01/13/2023]
Abstract
Presenilin-1 (PS1) is the catalytic component of the γ-secretase complex. In this study, we explore if PS1 participates in the processing of the cholinergic acetylcholinesterase (AChE). The major AChE variant expressed in the brain is a tetramer (G(4)) bound to a proline-rich membrane anchor (PRiMA). Overexpression of the transmembrane PRiMA protein in Chinese hamster ovary cells expressing AChE and treated with the γ-secretase inhibitor N-[N-(3,5-difluorophenacetyl)-l-alanyl]-S-phenylglycine t-butyl ester have enabled us to study whether, through its γ-secretase activity, PS1 participates in the processing of PRiMA-linked AChE. γ-Secretase inhibition led to a notable increase in the level of PRiMA-linked AChE, suggesting that γ-secretase is involved in the cleavage of PRiMA. We demonstrate that cleavage of PRiMA by γ-secretase results in a C-terminal PRiMA fragment. Immunofluorescence labeling allowed us to identify this PRiMA fragment in the nucleus. Moreover, we have determined changes in the proportion of the raft-residing AChE-PRiMA in a PS1 conditional knockout mouse. Our results are of interest as both enzymes have therapeutic relevance for Alzheimer's disease.
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Affiliation(s)
- María-Salud García-Ayllón
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas (CSIC), Sant Joan d'Alacant, Spain; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain; Unidad de Investigación, Hospital General Universitario de Elche, Fundación para el Fomento de la Investigación Sanitaria y Biomédica de la Comunitat Valenciana (FISABIO), Elche, Spain
| | - María-Letizia Campanari
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas (CSIC), Sant Joan d'Alacant, Spain; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - María-Fernanda Montenegro
- Departamento de Bioquímica y Biología Molecular-A, Universidad de Murcia, Regional Campus of International Excellence "Campus Mare Nostrum", Murcia, Spain
| | - Inmaculada Cuchillo-Ibáñez
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas (CSIC), Sant Joan d'Alacant, Spain; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Olivia Belbin
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain; Memory Unit, Neurology Department, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
| | - Alberto Lleó
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain; Memory Unit, Neurology Department, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
| | - Karl Tsim
- Division of Life Science and Center for Chinese Medicine, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Cecilio J Vidal
- Departamento de Bioquímica y Biología Molecular-A, Universidad de Murcia, Regional Campus of International Excellence "Campus Mare Nostrum", Murcia, Spain
| | - Javier Sáez-Valero
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas (CSIC), Sant Joan d'Alacant, Spain; Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain.
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13
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Bi CWC, Luk WKW, Campanari ML, Liu YH, Xu L, Lau KM, Xu ML, Choi RCY, Sáez-Valero J, Tsim KWK. Quantification of the transcripts encoding different forms of AChE in various cell types: real-time PCR coupled with standards in revealing the copy number. J Mol Neurosci 2014; 53:461-8. [PMID: 24385197 DOI: 10.1007/s12031-013-0210-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2013] [Accepted: 12/10/2013] [Indexed: 01/05/2023]
Abstract
Acetylcholinesterase (AChE) is encoded by a single gene, and the alternative splicing at the 3' end produces different isoforms, including tailed (AChET), read-through (AChER), and hydrophobic (AChEH). Different forms of this enzyme exist in different cell types. Each AChE form has been proposed to have unique function, and all of them could be found in same cell type. Thus, the splicing process of different AChE forms remains unclear. Here, we aimed to establish a quantification method in measuring the absolute amount of each AChE splicing variants within a cell type. By using real-time PCR coupled with standard curves of defined copy of AChE variants, the copies of AChET transcript per 100 ng of total RNA were 5.7 × 10(4) in PC12 (rat neuronal cell), 1.3 × 10(4) in Caco-2 (human intestinal cell), 0.67 × 10(4) in TF-1 (human erythropoietic precursor), 133.3 in SH-SY5Y (human neuronal cell), and 56.7 in human umbilical vein endothelial cells (human endothelial cells). The copies of AChEH in these cell types were 0.3 × 10(4), 3.3 × 10(4), 2.7 × 10(4), 133.3, and 46.7, respectively, and AChER were 0.07 × 10(4), 0.13 × 10(4), 890, 3.3, and 2.7, respectively. Furthermore, PC12 and TF-1 cells were chosen for the analysis of AChE splicing pattern during differentiation. The results demonstrated a selective increase in AChET mRNA but not AChER or AChEH mRNAs in PC12 upon nerve growth factor-induced neuronal differentiation. PC12 cells could therefore act as a good cell model for the study on alternative splicing mechanism and regulation of AChET.
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Affiliation(s)
- 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
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14
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Choi RC, Chen VP, Luk WK, Yung AW, Ng AH, Dong TT, Tsim KW. Expression of cAMP-responsive element binding proteins (CREBs) in fast- and slow-twitch muscles: A signaling pathway to account for the synaptic expression of collagen-tailed subunit (ColQ) of acetylcholinesterase at the rat neuromuscular junction. Chem Biol Interact 2013; 203:282-6. [DOI: 10.1016/j.cbi.2012.10.025] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2012] [Revised: 10/25/2012] [Accepted: 10/30/2012] [Indexed: 10/27/2022]
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15
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Luk WKW, Chen VP, Choi RCY, Tsim KWK. N-linked glycosylation of dimeric acetylcholinesterase in erythrocytes is essential for enzyme maturation and membrane targeting. FEBS J 2012; 279:3229-39. [PMID: 22805525 DOI: 10.1111/j.1742-4658.2012.08708.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Acetylcholinesterase (AChE) is well-known for its cholinergic functions in the nervous system; however, this enzyme is also found in other tissues where its function is still not understood. AChE is synthesized through alternative splicing as splicing variants, with isoforms including read-through (AChE(R)), tailed (AChE(T)) and hydrophobic (AChE(H)). In human erythrocytes, AChE(H) is a glycophosphatidylinositol-linked dimer on the plasma membrane. Three N-linked glycosylation sites have been identified in the catalytic domain of human AChE. Here, we investigate the roles of glycosylation in assembly and trafficking of human AChE(H). In transfected fibroblasts, expression of AChE(H) was able to mimic the function of the dimeric form of AChE on the erythrocyte membrane. A glycan-depleted form was constructed by site-directed mutagenesis. By comparison with the wild-type AChE(H), the mutant had a much lower enzymatic activity and a much higher K(m) value. In addition, the mutant was dimerized in the endoplasmic reticulum, but was not trafficked to the Golgi apparatus. The results suggest that the glycosylation may affect AChE(H) enzymatic activity and trafficking, but not dimer formation. The present findings indicate the significance of N-glycosylation in controlling the biosynthesis of the AChE(H) dimer form.
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Affiliation(s)
- Wilson K W Luk
- Division of Life Science, Center for Chinese Medicine and State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay Road, Hong Kong, China
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16
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Chan WKB, Chen VP, Luk WKW, Choi RCY, Tsim KWK. N-linked glycosylation of proline-rich membrane anchor (PRiMA) is not required for assembly and trafficking of globular tetrameric acetylcholinesterase. Neurosci Lett 2012; 523:71-5. [PMID: 22750213 DOI: 10.1016/j.neulet.2012.06.045] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2012] [Revised: 06/15/2012] [Accepted: 06/16/2012] [Indexed: 12/01/2022]
Abstract
Acetylcholinesterase (AChE) is organized into globular tetramers (G(4)) by a structural protein called proline-rich membrane anchor (PRiMA), anchoring it into the cell membrane of neurons in the brain. The assembly of AChE tetramers with PRiMA requires the presence of a C-terminal "t-peptide" in the AChE catalytic subunit (AChE(T)). The glycosylation of AChE(T) is known to be required for its proper assembly and trafficking; however, the role of PRiMA glycosylation in the oligomer assembly has not been revealed. PRiMA is a glycoprotein containing two putative N-linked glycosylation sites. By using site-directed mutagenesis, the asparagine-43 was identified to be the N-linked glycosylation site of PRiMA. Abolishing glycosylation on mouse PRiMA appeared not to affect its assembly with AChE(T), the enzymatic properties of AChE, and the membrane trafficking of PRiMA-linked AChE tetramers. This result is contrary to the reports that glycosylation is essential for conformation and trafficking of membrane glycoproteins.
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Affiliation(s)
- Wallace K B Chan
- Division of Life Science, Center for Chinese Medicine and State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay Road, Hong Kong Special Administrative Region
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17
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Chen VP, Luk WKW, Chan WKB, Leung KW, Guo AJY, Chan GKL, Xu SL, Choi RCY, Tsim KWK. Molecular Assembly and Biosynthesis of Acetylcholinesterase in Brain and Muscle: the Roles of t-peptide, FHB Domain, and N-linked Glycosylation. Front Mol Neurosci 2011; 4:36. [PMID: 22046147 PMCID: PMC3200509 DOI: 10.3389/fnmol.2011.00036] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2011] [Accepted: 10/10/2011] [Indexed: 11/13/2022] Open
Abstract
Acetylcholinesterase (AChE) is responsible for the hydrolysis of the neurotransmitter, acetylcholine, in the nervous system. The functional localization and oligomerization of AChE T variant are depending primarily on the association of their anchoring partners, either collagen tail (ColQ) or proline-rich membrane anchor (PRiMA). Complexes with ColQ represent the asymmetric forms (A(12)) in muscle, while complexes with PRiMA represent tetrameric globular forms (G(4)) mainly found in brain and muscle. Apart from these traditional molecular forms, a ColQ-linked asymmetric form and a PRiMA-linked globular form of hybrid cholinesterases (ChEs), having both AChE and BChE catalytic subunits, were revealed in chicken brain and muscle. The similarity of various molecular forms of AChE and BChE raises interesting question regarding to their possible relationship in enzyme assembly and localization. The focus of this review is to provide current findings about the biosynthesis of different forms of ChEs together with their anchoring proteins.
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Affiliation(s)
- Vicky P Chen
- Division of Life Science, Center for Chinese Medicine, The Hong Kong University of Science and Technology Hong Kong, China
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18
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Petrov KA, Yagodina LO, Valeeva GR, Lannik NI, Nikitashina AD, Rizvanov AA, Zobov VV, Bukharaeva EA, Reznik VS, Nikolsky EE, Vyskočil F. Different sensitivities of rat skeletal muscles and brain to novel anti-cholinesterase agents, alkylammonium derivatives of 6-methyluracil (ADEMS). Br J Pharmacol 2011; 163:732-44. [PMID: 21232040 DOI: 10.1111/j.1476-5381.2011.01211.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND AND PURPOSE The rat respiratory muscle diaphragm has markedly lower sensitivity than the locomotor muscle extensor digitorum longus (EDL) to the new acetylcholinesterase (AChE) inhibitors, alkylammonium derivatives of 6-methyluracil (ADEMS). This study evaluated several possible reasons for differing sensitivity between the diaphragm and limb muscles and between the muscles and the brain. EXPERIMENTAL APPROACH Increased amplitude and prolonged decay time of miniature endplate currents were used to assess anti-cholinesterase activity in muscles. In hippocampal slices, induction of synchronous network activity was used to follow cholinesterase inhibition. The inhibitor sensitivities of purified AChE from the EDL and brain were also estimated. KEY RESULTS The intermuscular difference in sensitivity to ADEMS is partly explained caused by a higher level of mRNA and activity of 1,3-bis[5(diethyl-o-nitrobenzylammonium)pentyl]-6-methyluracildibromide (C-547)-resistant BuChE in the diaphragm. Moreover, diaphragm AChE was more than 20 times less sensitive to C-547 than that from the EDL. Sensitivity of the EDL to C-547 dramatically decreased after treadmill exercises that increased the amount of PRiMA AChE(G4), but not ColQ AChE(A12) molecular forms. The A12 form present in muscles appeared more sensitive to C-547. The main form of AChE in brain, PRiMA AChE(G4), was apparently less sensitive because brain cholinesterase activity was almost three orders of magnitude more resistant to C-547 than that of the EDL. CONCLUSIONS AND IMPLICATIONS Our findings suggest that ADEMS compounds could be used for the selective inhibition of AChEs and as potential therapeutic tools.
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Affiliation(s)
- Konstantin A Petrov
- A.E.Arbusov Institute of Organic and Physical Chemistry, Russian Academy of Sciences, Kazan, Russia
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19
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Bernard V, Girard E, Hrabovska A, Camp S, Taylor P, Plaud B, Krejci E. Distinct localization of collagen Q and PRiMA forms of acetylcholinesterase at the neuromuscular junction. Mol Cell Neurosci 2010; 46:272-81. [PMID: 20883790 DOI: 10.1016/j.mcn.2010.09.010] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2010] [Revised: 09/20/2010] [Accepted: 09/22/2010] [Indexed: 11/30/2022] Open
Abstract
Acetylcholinesterase (AChE) terminates the action of acetylcholine at cholinergic synapses thereby preventing rebinding of acetylcholine to nicotinic postsynaptic receptors at the neuromuscular junction. Here we show that AChE is not localized close to these receptors on the postsynaptic surface, but is instead clustered along the presynaptic membrane and deep in the postsynaptic folds. Because AChE is anchored by ColQ in the basal lamina and is linked to the plasma membrane by a transmembrane subunit (PRiMA), we used a genetic approach to evaluate the respective contribution of each anchoring oligomer. By visualization and quantification of AChE in mouse strains devoid of ColQ, PRiMA or AChE, specifically in the muscle, we found that along the nerve terminus the vast majority of AChE is anchored by ColQ that is only produced by the muscle, whereas very minor amounts of AChE are anchored by PRiMA that is produced by motoneurons. In its synaptic location, AChE is therefore positioned to scavenge ACh that effluxes from the nerve by non-quantal release. AChE-PRiMA, produced by the muscle, is diffusely distributed along the muscle in extrajunctional regions.
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Affiliation(s)
- Véronique Bernard
- Université Paris Descartes, 45 rue des Saints Pères, 75006 Paris, France.
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20
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Xie HQ, Leung KW, Chen VP, Chan GK, Xu SL, Guo AJ, Zhu KY, Zheng KY, Bi CW, Zhan JY, Chan WK, Choi RC, Tsim KW. PRiMA directs a restricted localization of tetrameric AChE at synapses. Chem Biol Interact 2010; 187:78-83. [DOI: 10.1016/j.cbi.2010.02.018] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2009] [Revised: 02/08/2010] [Accepted: 02/09/2010] [Indexed: 11/24/2022]
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21
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Henderson Z, Matto N, John D, Nalivaeva NN, Turner AJ. Co-localization of PRiMA with acetylcholinesterase in cholinergic neurons of rat brain: an immunocytochemical study. Brain Res 2010; 1344:34-42. [PMID: 20471375 DOI: 10.1016/j.brainres.2010.05.022] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2010] [Revised: 05/06/2010] [Accepted: 05/06/2010] [Indexed: 12/12/2022]
Abstract
In the central nervous system, acetylcholinesterase (AChE) is present in a tetrameric form that is anchored to membranes via a proline-rich membrane anchor (PRiMA). Previously it has been found that principal cholinergic neurons in the brain express high concentrations of AChE enzymic activity at their neuronal membranes. The aim of this study was to use immunocytochemical methods to determine the distribution of PRiMA in these neurons in the rat brain. Confocal laser and electron microscopic investigations showed that PRiMA immunoreactivity is associated with the membranes of the somata, dendrites and axons of cholinergic neurons in the basal forebrain, striatum and pedunculopontine nuclei, i.e. the neurons that innervate forebrain and brainstem structures. In these neurones, PRiMA also co-localizes with AChE immunoreactivity at the plasma membrane. PRiMA label was absent from neighboring GABAergic neurons, and from other neurons of the brain known to express high levels of AChE enzymic activity including cranial nerve motor neurons and dopaminergic neurons of the substantia nigra zona compacta. A strong association of AChE with PRiMA at the plasma membrane is therefore a feature specific to principal cholinergic neurons that innervate the central nervous system.
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Affiliation(s)
- Zaineb Henderson
- Faculty of Biological Sciences, Institute of Membrane and Systems Biology, University of Leeds, Leeds LS2 9JT, UK.
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22
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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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23
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Tsim KWK, Leung KW, Mok KW, Chen VP, Zhu KY, Zhu JTT, Guo AJY, Bi CWC, Zheng KYZ, Lau DTW, Xie HQ, Choi RCY. Expression and Localization of PRiMA-linked globular form acetylcholinesterase in vertebrate neuromuscular junctions. J Mol Neurosci 2009; 40:40-6. [PMID: 19680821 DOI: 10.1007/s12031-009-9251-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2009] [Accepted: 07/20/2009] [Indexed: 11/28/2022]
Abstract
Acetylcholinesterase (AChE) is well known to process different molecular forms via the distinct interacting partners. Proline-rich membrane anchor (PRiMA)-linked tetrameric globular AChE (G4 AChE) is mainly found in the vertebrate brain; however, recent studies from our laboratory have suggested its existence at neuromuscular junctions (nmjs). Both muscle and motor neuron express AChE at the nmjs. In muscle, the expression of PRiMA-linked AChE is down-regulated during myogenic differentiation and by motor neuron innervation. As compared with muscle, spinal cord possessed higher total AChE activity and contained PRiMA-linked AChE forms. The spinal cord expression of this form increased during development. More importantly, PRiMA-linked G4 AChE identified as aggregates localized at nmjs. These findings suggest that the restricted localization of PRiMA-linked G4 AChE at the nmjs could be contributed by the pre-synaptic motor neuron and/or the post-synaptic muscle fiber.
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Affiliation(s)
- Karl W K Tsim
- Department of Biology, The Hong Kong University of Science and Technology, Clear Water Bay Road, Hong Kong, SAR, China
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