1
|
Qiu Y, Gao Y, Huang B, Bai Q, Zhao Y. Transport mechanism of presynaptic high-affinity choline uptake by CHT1. Nat Struct Mol Biol 2024; 31:701-709. [PMID: 38589607 DOI: 10.1038/s41594-024-01259-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Accepted: 01/19/2024] [Indexed: 04/10/2024]
Abstract
Choline is a vital nutrient and a precursor for the biosynthesis of essential metabolites, including acetylcholine (ACh), that play a central role in fetal development, especially in the brain. In cholinergic neurons, the high-affinity choline transporter (CHT1) provides an extraordinarily efficient reuptake mechanism to reutilize choline derived from intrasynaptical ACh hydrolysis and maintain ACh synthesis in the presynapse. Here, we determined structures of human CHT1 in three discrete states: the outward-facing state bound with the competitive inhibitor hemicholinium-3 (HC-3); the inward-facing occluded state bound with the substrate choline; and the inward-facing apo open state. Our structures and functional characterizations elucidate how the inhibitor and substrate are recognized. Moreover, our findings shed light on conformational changes when transitioning from an outward-facing to an inward-facing state and establish a framework for understanding the transport cycle, which relies on the stabilization of the outward-facing state by a short intracellular helix, IH1.
Collapse
Affiliation(s)
- Yunlong Qiu
- Key Laboratory of Biomacromolecules (CAS), National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
- State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Yiwei Gao
- Key Laboratory of Biomacromolecules (CAS), National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
- State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Bo Huang
- Beijing StoneWise Technology Co Ltd., Beijing, China
| | - Qinru Bai
- Key Laboratory of Biomacromolecules (CAS), National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
- State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Yan Zhao
- Key Laboratory of Biomacromolecules (CAS), National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.
- State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China.
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China.
| |
Collapse
|
2
|
Nguyen XTA, Le TNU, Nguyen TQ, Thi Thuy Ha H, Artati A, Leong NCP, Nguyen DT, Lim PY, Susanto AV, Huang Q, Fam L, Leong LN, Bonne I, Lee A, Granadillo JL, Gooch C, Yu D, Huang H, Soong TW, Chang MW, Wenk MR, Adamski J, Cazenave-Gassiot A, Nguyen LN. MFSD7c functions as a transporter of choline at the blood-brain barrier. Cell Res 2024; 34:245-257. [PMID: 38302740 PMCID: PMC10907603 DOI: 10.1038/s41422-023-00923-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Accepted: 12/26/2023] [Indexed: 02/03/2024] Open
Abstract
Mutations in the orphan transporter MFSD7c (also known as Flvcr2), are linked to Fowler syndrome. Here, we used Mfsd7c knockout (Mfsd7c-/-) mice and cell-based assays to reveal that MFSD7c is a choline transporter at the blood-brain barrier (BBB). We performed comprehensive metabolomics analysis and detected differential changes of metabolites in the brains and livers of Mfsd7c-/-embryos. Particularly, we found that choline-related metabolites were altered in the brains but not in the livers of Mfsd7c-/- embryos. Thus, we hypothesized that MFSD7c regulates the level of choline in the brain. Indeed, expression of human MFSD7c in cells significantly increased choline uptake. Interestingly, we showed that choline uptake by MFSD7c is greatly increased by choline-metabolizing enzymes, leading us to demonstrate that MFSD7c is a facilitative transporter of choline. Furthermore, single-cell patch clamp analysis showed that the import of choline by MFSD7c is electrogenic. Choline transport function of MFSD7c was shown to be conserved in vertebrates, but not in yeasts. We demonstrated that human MFSD7c is a functional ortholog of HNM1, the yeast choline importer. We also showed that several missense mutations identified in patients exhibiting Fowler syndrome had abolished or reduced choline transport activity. Mice lacking Mfsd7c in endothelial cells of the central nervous system suppressed the import of exogenous choline from blood but unexpectedly had increased choline levels in the brain. Stable-isotope tracing study revealed that MFSD7c was required for exporting choline derived from lysophosphatidylcholine in the brain. Collectively, our work identifies MFSD7c as a choline exporter at the BBB and provides a foundation for future work to reveal the disease mechanisms of Fowler syndrome.
Collapse
Affiliation(s)
- Xuan Thi Anh Nguyen
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Thanh Nha Uyen Le
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Hudson Institute of Medical Research, Clayton, VIC, Australia
| | - Toan Q Nguyen
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Hoa Thi Thuy Ha
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Anna Artati
- Metabolomics and Proteomics Core, Helmholtz Center Munich, German Research Center for Environmental Health, Neuherberg, Germany
| | - Nancy C P Leong
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Dat T Nguyen
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Pei Yen Lim
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Singapore Lipidomics Incubator (SLING), Life Sciences Institute, National University of Singapore, Singapore, Singapore
| | - Adelia Vicanatalita Susanto
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- NUS Synthetic Biology for Clinical and Technological Innovation (SynCTI), National University of Singapore, Singapore, Singapore
- Synthetic Biology Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Qianhui Huang
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Ling Fam
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Lo Ngah Leong
- Electron Microscopy Unit, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Isabelle Bonne
- Electron Microscopy Unit, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Department of Microbiology and Immunology, Immunology Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Life Sciences Institute, Immunology Programme, National University of Singapore, Singapore, Singapore
| | - Angela Lee
- Division of Genetics and Genomic Medicine, Department of Pediatrics, Washington University in St Louis, Saint Louis, MO, USA
| | - Jorge L Granadillo
- Division of Genetics and Genomic Medicine, Department of Pediatrics, Washington University in St Louis, Saint Louis, MO, USA
| | - Catherine Gooch
- Division of Genetics and Genomic Medicine, Department of Pediatrics, Washington University in St Louis, Saint Louis, MO, USA
| | - Dejie Yu
- Electrophysiology Core Facility, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Hua Huang
- Electrophysiology Core Facility, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Healthy Longevity Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Cardiovascular Diseases Program, National University of Singapore, Singapore, Singapore
| | - Tuck Wah Soong
- Electrophysiology Core Facility, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Healthy Longevity Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Cardiovascular Diseases Program, National University of Singapore, Singapore, Singapore
| | - Matthew Wook Chang
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- NUS Synthetic Biology for Clinical and Technological Innovation (SynCTI), National University of Singapore, Singapore, Singapore
- Synthetic Biology Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Markus R Wenk
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Singapore Lipidomics Incubator (SLING), Life Sciences Institute, National University of Singapore, Singapore, Singapore
| | - Jerzy Adamski
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Institute of Experimental Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany
- Institute of Biochemistry, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Amaury Cazenave-Gassiot
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Singapore Lipidomics Incubator (SLING), Life Sciences Institute, National University of Singapore, Singapore, Singapore
| | - Long N Nguyen
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.
- Singapore Lipidomics Incubator (SLING), Life Sciences Institute, National University of Singapore, Singapore, Singapore.
- Life Sciences Institute, Immunology Programme, National University of Singapore, Singapore, Singapore.
- Cardiovascular Diseases Program, National University of Singapore, Singapore, Singapore.
- Immunology Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.
| |
Collapse
|
3
|
Pereira PA, Tavares M, Laires M, Mota B, Madeira MD, Paula-Barbosa MM, Cardoso A. Effects of Aging and Nerve Growth Factor on Neuropeptide Expression and Cholinergic Innervation of the Rat Basolateral Amygdala. BIOLOGY 2024; 13:155. [PMID: 38534426 DOI: 10.3390/biology13030155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Revised: 02/22/2024] [Accepted: 02/23/2024] [Indexed: 03/28/2024]
Abstract
The basolateral amygdala (BLA) contains interneurons that express neuropeptide Y (NPY) and vasoactive intestinal polypeptide (VIP), both of which are involved in the regulation of functions and behaviors that undergo deterioration with aging. There is considerable evidence that, in some brain areas, the expression of NPY and VIP might be modulated by acetylcholine. Importantly, the BLA is one of the brain regions that has one of the densest cholinergic innervations, which arise mainly from the basal forebrain cholinergic neurons. These cholinergic neurons depend on nerve growth factor (NGF) for their survival, connectivity, and function. Thus, in this study, we sought to determine if aging alters the densities of NPY- and VIP-positive neurons and cholinergic varicosities in the BLA and, in the affirmative, if those changes might rely on insufficient trophic support provided by NGF. The number of NPY-positive neurons was significantly reduced in aged rats, whereas the number of VIP-immunoreactive neurons was unaltered. The decreased NPY expression was fully reversed by the infusion of NGF in the lateral ventricle. The density of cholinergic varicosities was similar in adult and old rats. On the other hand, the density of cholinergic varicosities is significantly higher in old rats treated with NGF than in adult and old rats. Our results indicate a dissimilar resistance of different populations of BLA interneurons to aging. Furthermore, the present data also show that the BLA cholinergic innervation is particularly resistant to aging effects. Finally, our results also show that the reduced NPY expression in the BLA of aged rats can be related to changes in the NGF neurotrophic support.
Collapse
Affiliation(s)
- Pedro A Pereira
- Unit of Anatomy, Department of Biomedicine, Faculty of Medicine, University of Porto, Alameda Professor Hernâni Monteiro, 4200-319 Porto, Portugal
- NeuroGen Research Group, Center for Health Technology and Services Research (CINTESIS), Rua Dr. Plácido da Costa, 4200-450 Porto, Portugal
- CINTESIS@RISE, Faculty of Medicine, University of Porto, Alameda Professor Hernâni Monteiro, 4200-319 Porto, Portugal
| | - Marta Tavares
- Unit of Anatomy, Department of Biomedicine, Faculty of Medicine, University of Porto, Alameda Professor Hernâni Monteiro, 4200-319 Porto, Portugal
| | - Miguel Laires
- Unit of Anatomy, Department of Biomedicine, Faculty of Medicine, University of Porto, Alameda Professor Hernâni Monteiro, 4200-319 Porto, Portugal
| | - Bárbara Mota
- Unit of Anatomy, Department of Biomedicine, Faculty of Medicine, University of Porto, Alameda Professor Hernâni Monteiro, 4200-319 Porto, Portugal
| | - Maria Dulce Madeira
- Unit of Anatomy, Department of Biomedicine, Faculty of Medicine, University of Porto, Alameda Professor Hernâni Monteiro, 4200-319 Porto, Portugal
- NeuroGen Research Group, Center for Health Technology and Services Research (CINTESIS), Rua Dr. Plácido da Costa, 4200-450 Porto, Portugal
- CINTESIS@RISE, Faculty of Medicine, University of Porto, Alameda Professor Hernâni Monteiro, 4200-319 Porto, Portugal
| | - Manuel M Paula-Barbosa
- Unit of Anatomy, Department of Biomedicine, Faculty of Medicine, University of Porto, Alameda Professor Hernâni Monteiro, 4200-319 Porto, Portugal
| | - Armando Cardoso
- Unit of Anatomy, Department of Biomedicine, Faculty of Medicine, University of Porto, Alameda Professor Hernâni Monteiro, 4200-319 Porto, Portugal
- NeuroGen Research Group, Center for Health Technology and Services Research (CINTESIS), Rua Dr. Plácido da Costa, 4200-450 Porto, Portugal
- CINTESIS@RISE, Faculty of Medicine, University of Porto, Alameda Professor Hernâni Monteiro, 4200-319 Porto, Portugal
| |
Collapse
|
4
|
Weiler M, Stieger KC, Shroff K, Klein JP, Wood WH, Zhang Y, Chandrasekaran P, Lehrmann E, Camandola S, Long JM, Mattson MP, Becker KG, Rapp PR. Transcriptional changes in the rat brain induced by repetitive transcranial magnetic stimulation. Front Hum Neurosci 2023; 17:1215291. [PMID: 38021223 PMCID: PMC10679736 DOI: 10.3389/fnhum.2023.1215291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Accepted: 10/03/2023] [Indexed: 12/01/2023] Open
Abstract
Introduction Transcranial Magnetic Stimulation (TMS) is a noninvasive technique that uses pulsed magnetic fields to affect the physiology of the brain and central nervous system. Repetitive TMS (rTMS) has been used to study and treat several neurological conditions, but its complex molecular basis is largely unexplored. Methods Utilizing three experimental rat models (in vitro, ex vivo, and in vivo) and employing genome-wide microarray analysis, our study reveals the extensive impact of rTMS treatment on gene expression patterns. Results These effects are observed across various stimulation protocols, in diverse tissues, and are influenced by time and age. Notably, rTMS-induced alterations in gene expression span a wide range of biological pathways, such as glutamatergic, GABAergic, and anti-inflammatory pathways, ion channels, myelination, mitochondrial energetics, multiple neuron-and synapse-specific genes. Discussion This comprehensive transcriptional analysis induced by rTMS stimulation serves as a foundational characterization for subsequent experimental investigations and the exploration of potential clinical applications.
Collapse
Affiliation(s)
- Marina Weiler
- Laboratory of Behavioral Neuroscience, National Institute on Aging, National Institutes of Health, Baltimore, MD, United States
| | - Kevin C. Stieger
- Laboratory of Behavioral Neuroscience, National Institute on Aging, National Institutes of Health, Baltimore, MD, United States
| | - Kavisha Shroff
- Laboratory of Genetics and Genomics, National Institute on Aging, National Institutes of Health, Baltimore, MD, United States
| | - Jessie P. Klein
- Laboratory of Genetics and Genomics, National Institute on Aging, National Institutes of Health, Baltimore, MD, United States
| | - William H. Wood
- Laboratory of Genetics and Genomics, National Institute on Aging, National Institutes of Health, Baltimore, MD, United States
| | - Yongqing Zhang
- Laboratory of Genetics and Genomics, National Institute on Aging, National Institutes of Health, Baltimore, MD, United States
| | - Prabha Chandrasekaran
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, MD, United States
| | - Elin Lehrmann
- Laboratory of Genetics and Genomics, National Institute on Aging, National Institutes of Health, Baltimore, MD, United States
| | - Simonetta Camandola
- Laboratory of Neurosciences, National Institute on Aging, National Institutes of Health, Baltimore, MD, United States
| | - Jeffrey M. Long
- Laboratory of Behavioral Neuroscience, National Institute on Aging, National Institutes of Health, Baltimore, MD, United States
| | - Mark P. Mattson
- Laboratory of Neurosciences, National Institute on Aging, National Institutes of Health, Baltimore, MD, United States
| | - Kevin G. Becker
- Laboratory of Genetics and Genomics, National Institute on Aging, National Institutes of Health, Baltimore, MD, United States
| | - Peter R. Rapp
- Laboratory of Behavioral Neuroscience, National Institute on Aging, National Institutes of Health, Baltimore, MD, United States
| |
Collapse
|
5
|
Nimgampalle M, Chakravarthy H, Sharma S, Shree S, Bhat AR, Pradeepkiran JA, Devanathan V. Neurotransmitter systems in the etiology of major neurological disorders: Emerging insights and therapeutic implications. Ageing Res Rev 2023; 89:101994. [PMID: 37385351 DOI: 10.1016/j.arr.2023.101994] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2023] [Revised: 06/21/2023] [Accepted: 06/25/2023] [Indexed: 07/01/2023]
Abstract
Neurotransmitters serve as chemical messengers playing a crucial role in information processing throughout the nervous system, and are essential for healthy physiological and behavioural functions in the body. Neurotransmitter systems are classified as cholinergic, glutamatergic, GABAergic, dopaminergic, serotonergic, histaminergic, or aminergic systems, depending on the type of neurotransmitter secreted by the neuron, allowing effector organs to carry out specific functions by sending nerve impulses. Dysregulation of a neurotransmitter system is typically linked to a specific neurological disorder. However, more recent research points to a distinct pathogenic role for each neurotransmitter system in more than one neurological disorder of the central nervous system. In this context, the review provides recently updated information on each neurotransmitter system, including the pathways involved in their biochemical synthesis and regulation, their physiological functions, pathogenic roles in diseases, current diagnostics, new therapeutic targets, and the currently used drugs for associated neurological disorders. Finally, a brief overview of the recent developments in neurotransmitter-based therapeutics for selected neurological disorders is offered, followed by future perspectives in that area of research.
Collapse
Affiliation(s)
- Mallikarjuna Nimgampalle
- Department of Biology, Indian Institute of Science Education and Research Tirupati (IISER T), Transit campus, Karakambadi Road, Mangalam, Tirupati 517507, Andhra Pradesh, India
| | - Harshini Chakravarthy
- Department of Biology, Indian Institute of Science Education and Research Tirupati (IISER T), Transit campus, Karakambadi Road, Mangalam, Tirupati 517507, Andhra Pradesh, India.
| | - Sapana Sharma
- Department of Biology, Indian Institute of Science Education and Research Tirupati (IISER T), Transit campus, Karakambadi Road, Mangalam, Tirupati 517507, Andhra Pradesh, India
| | - Shruti Shree
- Department of Biology, Indian Institute of Science Education and Research Tirupati (IISER T), Transit campus, Karakambadi Road, Mangalam, Tirupati 517507, Andhra Pradesh, India
| | - Anoop Ramachandra Bhat
- Department of Biology, Indian Institute of Science Education and Research Tirupati (IISER T), Transit campus, Karakambadi Road, Mangalam, Tirupati 517507, Andhra Pradesh, India
| | | | - Vasudharani Devanathan
- Department of Biology, Indian Institute of Science Education and Research Tirupati (IISER T), Transit campus, Karakambadi Road, Mangalam, Tirupati 517507, Andhra Pradesh, India.
| |
Collapse
|
6
|
Yamashita S, Kawada N, Wang W, Susaki K, Takeda Y, Kimura M, Iwama Y, Miura Y, Sugano M, Matsuoka R. Effects of egg yolk choline intake on cognitive functions and plasma choline levels in healthy middle-aged and older Japanese: a randomized double-blinded placebo-controlled parallel-group study. Lipids Health Dis 2023; 22:75. [PMID: 37340479 PMCID: PMC10280906 DOI: 10.1186/s12944-023-01844-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Accepted: 06/08/2023] [Indexed: 06/22/2023] Open
Abstract
BACKGROUND Choline, as a neurotransmitter acetylcholine precursor, is reportedly associated with cognitive function. Although there are several cohort and animal studies on choline-containing foods and cognitive function, only a few interventional studies were reported. Egg yolk is a rich source of different choline-containing chemical forms, such as phosphatidylcholine (PC), lysophosphatidylcholine (LPC), and α-glycerophosphocholine (α-GPC). This study aimed to investigate the effect of consuming 300 mg of egg yolk choline per day on cognitive function of Japanese adults. METHODS A 12-week, randomized, double-blind, placebo-controlled, parallel-group study was conducted in 41 middle-aged and elderly males and females (43.9% female) aged ≥ 60 years and ≤ 80 years without dementia. Participants were randomly assigned to placebo and choline groups. The choline group received a supplement containing egg yolk choline (300 mg/day), and the placebo group received an egg yolk supplement free from choline for 12 weeks. Assessments of Cognitrax, Trail Making Tests (TMT) part A and B, the MOS 36-Item Short-Form Health Survey (SF-36), the Simplified Japanese Version of the WHO-Five Well-Being Index (WHO-5), and plasma choline levels were performed before and 6 and 12 weeks after supplement intake. In the present study, 19 subjects (9 in the placebo group and 10 in the choline group) were excluded due to the violation of the discontinuation criteria or participant compliance, and 41 subjects were analyzed. RESULTS The change amount of verbal memory scores and verbal memory test-correct hit (delay) was significantly higher in the choline group than in the placebo group at baseline-6 and baseline-12 weeks. The plasma free choline level was significantly higher in the choline group compared with the placebo group at 6 weeks. Conversely, the choline group showed significantly lower Cognitrax processing speed scores, symbol digit coding testing correct responses, and SF-36 physical quality of life summary scores compared to the placebo group at 6 weeks. CONCLUSIONS The results suggested that continued 300 mg/day intake of egg yolk choline improved verbal memory, which is a part of cognitive functions. To confirm the observed effects of egg yolk choline, more well-designed and large-scale studies are warranted. TRIAL REGISTRATION Study protocols were pre-registered in the Clinical Trials Registration System (UMIN-CTR) (UMIN 000045050).
Collapse
Affiliation(s)
- Soyogu Yamashita
- R&D Division, Kewpie Corporation, 2-5-7, Sengawa-Cho, Chofu-Shi, Tokyo, 182-0002, Japan
| | - Naoki Kawada
- R&D Division, Kewpie Corporation, 2-5-7, Sengawa-Cho, Chofu-Shi, Tokyo, 182-0002, Japan
| | - Wei Wang
- R&D Division, Kewpie Corporation, 2-5-7, Sengawa-Cho, Chofu-Shi, Tokyo, 182-0002, Japan
| | - Kenta Susaki
- R&D Division, Kewpie Corporation, 2-5-7, Sengawa-Cho, Chofu-Shi, Tokyo, 182-0002, Japan
| | - Yumi Takeda
- R&D Division, Kewpie Corporation, 2-5-7, Sengawa-Cho, Chofu-Shi, Tokyo, 182-0002, Japan
| | - Mamoru Kimura
- R&D Division, Kewpie Corporation, 2-5-7, Sengawa-Cho, Chofu-Shi, Tokyo, 182-0002, Japan
| | - Yoshitaka Iwama
- Nihonbashi Cardiology Clinic, 13-4, Nihonbashi-Kodenmacho, Chuo-Ku, Tokyo, 103-0001, Japan
| | - Yutaka Miura
- Tokyo University of Agriculture and Technology, 3-8-1, Harumi-Cho, Fuchu-Shi, Tokyo, 183-8538, Japan
| | - Michihiro Sugano
- Professor emeritus of Kyushu University and Prefectural University of Kumamoto, Kyusyu, Japan
| | - Ryosuke Matsuoka
- R&D Division, Kewpie Corporation, 2-5-7, Sengawa-Cho, Chofu-Shi, Tokyo, 182-0002, Japan.
| |
Collapse
|
7
|
Li Y, Liu B, Yin X, Jiang Z, Fang C, Chen N, Zhang B, Dai L, Yin Y. Targeted demethylation of the SLC5A7 promotor inhibits colorectal cancer progression. Clin Epigenetics 2022; 14:92. [PMID: 35858918 PMCID: PMC9301853 DOI: 10.1186/s13148-022-01308-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Accepted: 07/04/2022] [Indexed: 02/08/2023] Open
Abstract
Background SLC5A7 (solute carrier family 5 member 7), also known as choline transporter 1 (CHT1), is downregulated in colorectal cancer (CRC) and functions as a tumor suppressor. However, the mechanisms underlying the inactivation of SLC5A7 in CRC remain to be elucidated. Results In the present study, two broad-spectrum demethylation agents (azacitidine and decitabine) employed to treat CRC cells significantly upregulated SLC5A7 expression. Further results based on the CRC cohort and TCGA database indicated that SLC5A7 promoter methylation inversely correlated with SLC5A7 expression, and the status of SLC5A7 promotor methylation showed a promising prognostic value for patients with CRC. Next, the dCas9-multiGCN4/scFv-TET1CD-based precision demethylation system was constructed, which could significantly and specifically promote SLC5A7 expression in CRC cells through sgRNA targeting the SLC5A7 promoter. Both in vitro and in vivo experiments demonstrated that targeted demethylation of SLC5A7 by dCas9-multiGCN4/scFv-TET1CD-sgSLC5A7 inhibited tumor growth by stabilizing p53 and regulating downstream targets. Conclusions Collectively, DNA promoter methylation caused inactivation of SLC5A7 in CRC, and targeted demethylation of SLC5A7 might be a therapeutic target for CRC and other cancers. Supplementary Information The online version contains supplementary material available at 10.1186/s13148-022-01308-5.
Collapse
Affiliation(s)
- Yang Li
- Department of Gastrointestinal Surgery, Guang'an People's Hospital, Guang'an, 638500, Sichuan, People's Republic of China.,Department of Gastrointestinal Surgery, West China Hospital and State Key Laboratory of Biotherapy, Sichuan University, Chengdu, 610041, Sichuan, People's Republic of China
| | - Baike Liu
- Department of Gastrointestinal Surgery, West China Hospital and State Key Laboratory of Biotherapy, Sichuan University, Chengdu, 610041, Sichuan, People's Republic of China
| | - Xiaonan Yin
- Department of Gastrointestinal Surgery, West China Hospital and State Key Laboratory of Biotherapy, Sichuan University, Chengdu, 610041, Sichuan, People's Republic of China
| | - Zhiyuan Jiang
- Department of Gastrointestinal Surgery, West China Hospital and State Key Laboratory of Biotherapy, Sichuan University, Chengdu, 610041, Sichuan, People's Republic of China
| | - Chao Fang
- Department of Gastrointestinal Surgery, West China Hospital and State Key Laboratory of Biotherapy, Sichuan University, Chengdu, 610041, Sichuan, People's Republic of China
| | - Na Chen
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu, 610041, Sichuan, People's Republic of China.,School of Pharmacy, Chengdu Medical College, Chengdu, 610500, People's Republic of China
| | - Bo Zhang
- Department of Gastrointestinal Surgery, West China Hospital and State Key Laboratory of Biotherapy, Sichuan University, Chengdu, 610041, Sichuan, People's Republic of China.
| | - Lei Dai
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu, 610041, Sichuan, People's Republic of China.
| | - Yuan Yin
- Department of Gastrointestinal Surgery, West China Hospital and State Key Laboratory of Biotherapy, Sichuan University, Chengdu, 610041, Sichuan, People's Republic of China.
| |
Collapse
|
8
|
Fukui T, Tateno H, Nakamura T, Yamada Y, Sato Y, Iwasaki N, Harashima H, Kadoya K. Retrograde Axonal Transport of Liposomes from Peripheral Tissue to Spinal Cord and DRGs by Optimized Phospholipid and CTB Modification. Int J Mol Sci 2022; 23:6661. [PMID: 35743104 PMCID: PMC9223829 DOI: 10.3390/ijms23126661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2022] [Revised: 06/10/2022] [Accepted: 06/13/2022] [Indexed: 11/16/2022] Open
Abstract
Despite recent advancements in therapeutic options for disorders of the central nervous system (CNS), the lack of an efficient drug-delivery system (DDS) hampers their clinical application. We hypothesized that liposomes could be optimized for retrograde transport in axons as a DDS from peripheral tissues to the spinal cord and dorsal root ganglia (DRGs). Three types of liposomes consisting of DSPC, DSPC/POPC, or POPC in combination with cholesterol (Chol) and polyethylene glycol (PEG) lipid were administered to sciatic nerves or the tibialis anterior muscle of mature rats. Liposomes in cell bodies were detected with infrared fluorescence of DiD conjugated to liposomes. Three days later, all nerve-administered liposomes were retrogradely transported to the spinal cord and DRGs, whereas only muscle-administered liposomes consisting of DSPC reached the spinal cord and DRGs. Modification with Cholera toxin B subunit improved the transport efficiency of liposomes to the spinal cord and DRGs from 4.5% to 17.3% and from 3.9% to 14.3% via nerve administration, and from 2.6% to 4.8% and from 2.3% to 4.1% via muscle administration, respectively. Modification with octa-arginine (R8) improved the transport efficiency via nerve administration but abolished the transport capability via muscle administration. These findings provide the initial data for the development of a novel DDS targeting the spinal cord and DRGs via peripheral administration.
Collapse
Affiliation(s)
- Takafumi Fukui
- Department of Orthopaedic Surgery, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita-15 Nishi-7, Sapporo 060-8638, Japan; (T.F.); (N.I.)
| | - Hironao Tateno
- Faculty of Pharmaceutical Sciences, Hokkaido University, Kita-12 Nishi-6, Kita-ku, Sapporo 060-0812, Japan; (H.T.); (Y.Y.); (Y.S.); (H.H.)
| | - Takashi Nakamura
- Faculty of Pharmaceutical Sciences, Hokkaido University, Kita-12 Nishi-6, Kita-ku, Sapporo 060-0812, Japan; (H.T.); (Y.Y.); (Y.S.); (H.H.)
| | - Yuma Yamada
- Faculty of Pharmaceutical Sciences, Hokkaido University, Kita-12 Nishi-6, Kita-ku, Sapporo 060-0812, Japan; (H.T.); (Y.Y.); (Y.S.); (H.H.)
| | - Yusuke Sato
- Faculty of Pharmaceutical Sciences, Hokkaido University, Kita-12 Nishi-6, Kita-ku, Sapporo 060-0812, Japan; (H.T.); (Y.Y.); (Y.S.); (H.H.)
| | - Norimasa Iwasaki
- Department of Orthopaedic Surgery, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita-15 Nishi-7, Sapporo 060-8638, Japan; (T.F.); (N.I.)
| | - Hideyoshi Harashima
- Faculty of Pharmaceutical Sciences, Hokkaido University, Kita-12 Nishi-6, Kita-ku, Sapporo 060-0812, Japan; (H.T.); (Y.Y.); (Y.S.); (H.H.)
| | - Ken Kadoya
- Department of Orthopaedic Surgery, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, Kita-15 Nishi-7, Sapporo 060-8638, Japan; (T.F.); (N.I.)
| |
Collapse
|
9
|
Anandakrishnan R, Tobey H, Nguyen S, Sandoval O, Klein BG, Costa BM. Cranial manipulation affects cholinergic pathway gene expression in aged rats. J Osteopath Med 2022; 122:95-103. [PMID: 34995434 DOI: 10.1515/jom-2021-0183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Accepted: 09/01/2021] [Indexed: 11/15/2022]
Abstract
CONTEXT Age-dependent dementia is a devastating disorder afflicting a growing older population. Although pharmacological agents improve symptoms of dementia, age-related comorbidities combined with adverse effects often outweigh their clinical benefits. Therefore, nonpharmacological therapies are being investigated as an alternative. In a previous pilot study, aged rats demonstrated improved spatial memory after osteopathic cranial manipulative medicine (OCMM) treatment. OBJECTIVES In this continuation of the pilot study, we examine the effect of OCMM on gene expression to elicit possible explanations for the improvement in spatial memory. METHODS OCMM was performed on six of 12 elderly rats every day for 7 days. Rats were then euthanized to obtain the brain tissue, from which RNA samples were extracted. RNA from three treated and three controls were of sufficient quality for sequencing. These samples were sequenced utilizing next-generation sequencing from Illumina NextSeq. The Cufflinks software suite was utilized to assemble transcriptomes and quantify the RNA expression level for each sample. RESULTS Transcriptome analysis revealed that OCMM significantly affected the expression of 36 genes in the neuronal pathway (false discovery rate [FDR] <0.004). The top five neuronal genes with the largest-fold change were part of the cholinergic neurotransmission mechanism, which is known to affect cognitive function. In addition, 39.9% of 426 significant differentially expressed (SDE) genes (FDR<0.004) have been previously implicated in neurological disorders. Overall, changes in SDE genes combined with their role in central nervous system signaling pathways suggest a connection to previously reported OCMM-induced behavioral and biochemical changes in aged rats. CONCLUSIONS Results from this pilot study provide sufficient evidence to support a more extensive study with a larger sample size. Further investigation in this direction will provide a better understanding of the molecular mechanisms of OCMM and its potential in clinical applications. With clinical validation, OCMM could represent a much-needed low-risk adjunct treatment for age-related dementia including Alzheimer's disease.
Collapse
Affiliation(s)
- Ramu Anandakrishnan
- Biomedical Sciences, Edward Via College of Osteopathic Medicine, Blacksburg, VA, USA.,Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA, USA.,Gibbs Cancer Center and Research Institute, Spartanburg, SC, USA
| | - Hope Tobey
- Sports and Osteopathic Medicine, Edward Via College of Osteopathic Medicine, Blacksburg, VA, USA
| | - Steven Nguyen
- Edward Via College of Osteopathic Medicine, Blacksburg, VA, USA
| | - Osscar Sandoval
- Edward Via College of Osteopathic Medicine, Blacksburg, VA, USA
| | - Bradley G Klein
- Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA, USA.,School of Neuroscience, Virginia Tech, Blacksburg, VA, USA
| | - Blaise M Costa
- Biomedical Sciences, Edward Via College of Osteopathic Medicine, Blacksburg, VA, USA.,Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA, USA
| |
Collapse
|
10
|
Maruyama T, Mano A, Ishii T, Kakinuma Y, Kaneda M. P2X 2 receptors supply extracellular choline as a substrate for acetylcholine synthesis. FEBS Open Bio 2021; 12:250-257. [PMID: 34787962 PMCID: PMC8727932 DOI: 10.1002/2211-5463.13332] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Revised: 11/03/2021] [Accepted: 11/16/2021] [Indexed: 01/14/2023] Open
Abstract
Acetylcholine (ACh), an excitatory neurotransmitter, is biosynthesized from choline in cholinergic neurons. Import from the extracellular space to the intracellular environment through the high-affinity choline transporter is currently regarded to be the only source of choline for ACh synthesis. We recently demonstrated that the P2X2 receptor, through which large cations permeate, functions as an alternative pathway for choline transport in the mouse retina. In the present study, we investigated whether choline entering cells through P2X2 receptors is used for ACh synthesis using a recombinant system. When P2X2 receptors expressed on HEK293 cell lines were stimulated with ATP, intracellular ACh concentrations increased. These results suggest that P2X2 receptors function in a novel pathway that supplies choline for ACh synthesis.
Collapse
Affiliation(s)
- Takuma Maruyama
- Department of Physiology, Nippon Medical School, Tokyo, Japan
| | - Asuka Mano
- Department of Physiology, Nippon Medical School, Tokyo, Japan
| | - Toshiyuki Ishii
- Department of Physiology, Nippon Medical School, Tokyo, Japan
| | | | - Makoto Kaneda
- Department of Physiology, Nippon Medical School, Tokyo, Japan
| |
Collapse
|
11
|
Magalhães-Gomes MPS, Camargos W, Valadão PAC, Garcias RS, Rodrigues HA, Andrade JN, Teixeira VP, Naves LA, Cavalcante WLG, Gallaci M, Guatimosim S, Prado VF, Prado MAM, Guatimosim C. Increased Cholinergic Tone Causes Pre-synaptic Neuromuscular Degeneration and is Associated with Impaired Diaphragm Function. Neuroscience 2021; 460:31-42. [PMID: 33548369 DOI: 10.1016/j.neuroscience.2020.12.025] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Revised: 12/08/2020] [Accepted: 12/17/2020] [Indexed: 11/25/2022]
Abstract
In vertebrates, muscle activity is dependent on acetylcholine (ACh) released from neuromuscular junctions (NMJs), and changes in cholinergic neurotransmission are linked to a variety of neuromuscular diseases, including congenital myasthenic syndromes (CMS). The storage and release of ACh depends on the activity of the Vesicular Acetylcholine Transporter (VAChT), a rate-limiting step for cholinergic neurotransmission whose loss of function mutations was shown to cause human congenital myasthenia. However, we know much less about increased VAChT activity, due to copy number variations, for example. Therefore, here we investigated the impact of increased VAChT expression and consequently ACh levels at the synaptic cleft of the diaphragm NMJs. We analyzed structure and function of nerve and muscles from a mouse model of cholinergic hyperfunction (ChAT-ChR2-EYFP) with increased expression of VAChT. Our results showed a significant increase of ACh released under evoked stimuli. However, we observed deleterious changes in synaptic vesicles cycle (impaired endocytosis and decrease in vesicles number), together with structural alterations of NMJs. Interestingly, ultrastructure analyses showed that synaptic vesicles from ChAT-ChR2-EYFP mice NMJs were larger, which might be related to increased ACh load. We also observed that these larger synaptic vesicles were less rounded in comparison with control. Finally, we showed that ChAT-ChR2-EYFP mice NMJs have compromised safety factor, possible due to the structural alterations we described. These findings reveal that physiological cholinergic activity is important to maintain the structure and function of the neuromuscular system and help to understand some of the neuromuscular adverse effects experienced by chronically increased NMJ neurotransmission, such as individuals treated with cholinesterase inhibitors.
Collapse
Affiliation(s)
- Matheus P S Magalhães-Gomes
- Departamento de Morfologia, ICB, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil; Departamento de Medicina, Faculdade Ciências Médicas de Minas Gerais, FCMMG, Belo Horizonte, MG, Brazil.
| | - Wallace Camargos
- Departamento de Fisiologia e Biofísica, ICB, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Priscila A C Valadão
- Departamento de Morfologia, ICB, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Rubens S Garcias
- Departamento de Morfologia, ICB, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Hermann A Rodrigues
- Departamento de Ciências Básicas da Vida, Instituto de Ciências da Vida, Universidade Federal de Juiz de Fora, Campus Governador Valadares, UFJF, Governador Valadares, MG, Brazil
| | - Jéssica N Andrade
- Departamento de Morfologia, ICB, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Vanessa P Teixeira
- Departamento de Fisiologia e Biofísica, ICB, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Lígia A Naves
- Departamento de Fisiologia e Biofísica, ICB, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Walter L G Cavalcante
- Departamento de Farmacologia, ICB, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Marcia Gallaci
- Departamento de Farmacologia, Instituto de Biociências, UNESP, Distrito de Rubião Jr., Botucatu, São Paulo, Brazil
| | - Silvia Guatimosim
- Departamento de Fisiologia e Biofísica, ICB, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Vânia F Prado
- Robarts Research Institute and Department of Physiology and Pharmacology and Anatomy & Cell Biology, University of Western Ontario, London, ON, Canada
| | - Marco A M Prado
- Robarts Research Institute and Department of Physiology and Pharmacology and Anatomy & Cell Biology, University of Western Ontario, London, ON, Canada
| | - Cristina Guatimosim
- Departamento de Morfologia, ICB, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
| |
Collapse
|
12
|
Bhat S, El-Kasaby A, Freissmuth M, Sucic S. Functional and Biochemical Consequences of Disease Variants in Neurotransmitter Transporters: A Special Emphasis on Folding and Trafficking Deficits. Pharmacol Ther 2020; 222:107785. [PMID: 33310157 PMCID: PMC7612411 DOI: 10.1016/j.pharmthera.2020.107785] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 12/02/2020] [Indexed: 01/30/2023]
Abstract
Neurotransmitters, such as γ-aminobutyric acid, glutamate, acetyl choline, glycine and the monoamines, facilitate the crosstalk within the central nervous system. The designated neurotransmitter transporters (NTTs) both release and take up neurotransmitters to and from the synaptic cleft. NTT dysfunction can lead to severe pathophysiological consequences, e.g. epilepsy, intellectual disability, or Parkinson’s disease. Genetic point mutations in NTTs have recently been associated with the onset of various neurological disorders. Some of these mutations trigger folding defects in the NTT proteins. Correct folding is a prerequisite for the export of NTTs from the endoplasmic reticulum (ER) and the subsequent trafficking to their pertinent site of action, typically at the plasma membrane. Recent studies have uncovered some of the key features in the molecular machinery responsible for transporter protein folding, e.g., the role of heat shock proteins in fine-tuning the ER quality control mechanisms in cells. The therapeutic significance of understanding these events is apparent from the rising number of reports, which directly link different pathological conditions to NTT misfolding. For instance, folding-deficient variants of the human transporters for dopamine or GABA lead to infantile parkinsonism/dystonia and epilepsy, respectively. From a therapeutic point of view, some folding-deficient NTTs are amenable to functional rescue by small molecules, known as chemical and pharmacological chaperones.
Collapse
Affiliation(s)
- Shreyas Bhat
- Institute of Pharmacology and the Gaston H. Glock Research Laboratories for Exploratory Drug Development, Center of Physiology and Pharmacology, Medical University of Vienna, A-1090 Vienna, Austria
| | - Ali El-Kasaby
- Institute of Pharmacology and the Gaston H. Glock Research Laboratories for Exploratory Drug Development, Center of Physiology and Pharmacology, Medical University of Vienna, A-1090 Vienna, Austria
| | - Michael Freissmuth
- Institute of Pharmacology and the Gaston H. Glock Research Laboratories for Exploratory Drug Development, Center of Physiology and Pharmacology, Medical University of Vienna, A-1090 Vienna, Austria
| | - Sonja Sucic
- Institute of Pharmacology and the Gaston H. Glock Research Laboratories for Exploratory Drug Development, Center of Physiology and Pharmacology, Medical University of Vienna, A-1090 Vienna, Austria.
| |
Collapse
|
13
|
Kunjiappan S, Pavadai P, Vellaichamy S, Ram Kumar Pandian S, Ravishankar V, Palanisamy P, Govindaraj S, Srinivasan G, Premanand A, Sankaranarayanan M, Theivendren P. Surface receptor‐mediated targeted drug delivery systems for enhanced cancer treatment: A state‐of‐the‐art review. Drug Dev Res 2020; 82:309-340. [DOI: 10.1002/ddr.21758] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 10/16/2020] [Accepted: 10/23/2020] [Indexed: 12/18/2022]
Affiliation(s)
- Selvaraj Kunjiappan
- Department of Biotechnology Kalasalingam Academy of Research and Education Krishnankoil Tamilnadu India
| | - Parasuraman Pavadai
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy M.S. Ramaiah University of Applied Sciences Bengaluru Karnataka India
| | - Sivakumar Vellaichamy
- Department of Pharmaceutics Arulmigu Kalasalingam College of Pharmacy Krishnankoil Tamilnadu India
| | | | | | - Ponnusamy Palanisamy
- School of Mechanical Engineering Vellore Institute of Technology Vellore Tamilnadu India
| | - Saravanan Govindaraj
- Department of Pharmaceutical Chemistry MNR College of Pharmacy Sangareddy Telangana India
| | - Gowshiki Srinivasan
- Department of Biotechnology Kalasalingam Academy of Research and Education Krishnankoil Tamilnadu India
| | - Adhvitha Premanand
- Department of Biotechnology Kalasalingam Academy of Research and Education Krishnankoil Tamilnadu India
| | | | - Panneerselvam Theivendren
- Department of Pharmaceutical Chemistry Swamy Vivekananda College of Pharmacy Elayampalayam, Namakkal Tamilnadu India
| |
Collapse
|
14
|
Ojiakor O, Rylett R. Modulation of sodium-coupled choline transporter CHT function in health and disease. Neurochem Int 2020; 140:104810. [DOI: 10.1016/j.neuint.2020.104810] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 06/16/2020] [Accepted: 07/09/2020] [Indexed: 12/27/2022]
|
15
|
Schneider C, O'Leary CE, Locksley RM. Regulation of immune responses by tuft cells. Nat Rev Immunol 2020; 19:584-593. [PMID: 31114038 DOI: 10.1038/s41577-019-0176-x] [Citation(s) in RCA: 145] [Impact Index Per Article: 36.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Tuft cells are rare, secretory epithelial cells that generated scant immunological interest until contemporaneous reports in 2016 linked tuft cells with type 2 immunity in the small intestine. Tuft cells have the capacity to produce an unusual spectrum of biological effector molecules, including IL-25, eicosanoids implicated in allergy (such as cysteinyl leukotrienes and prostaglandin D2) and the neurotransmitter acetylcholine. In most cases, the extracellular signals controlling tuft cell effector function are unknown, but signal transduction is thought to proceed via canonical, G protein-coupled receptor-dependent pathways involving components of the signalling pathway used by type II taste bud cells to sense sweet, bitter and umami compounds. Tuft cells are ideally positioned as chemosensory sentinels that can detect and relay information from diverse luminal substances via what appear to be stereotyped outputs to initiate both positive and aversive responses through populations of immune and neuronal cells. Despite recent insights, numerous questions remain regarding tuft cell lineage, diversity and effector mechanisms and how tuft cells interface with the immunological niche in the tissues where they reside.
Collapse
Affiliation(s)
- Christoph Schneider
- Department of Medicine, University of California-San Francisco, San Francisco, CA, USA
| | - Claire E O'Leary
- Department of Medicine, University of California-San Francisco, San Francisco, CA, USA
| | - Richard M Locksley
- Department of Medicine, University of California-San Francisco, San Francisco, CA, USA. .,Department of Microbiology & Immunology, University of California-San Francisco, San Francisco, CA, USA. .,Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, CA, USA.
| |
Collapse
|
16
|
Banerjee M, Arutyunov D, Brandwein D, Janetzki-Flatt C, Kolski H, Hume S, Leonard NJ, Watt J, Lacson A, Baradi M, Leslie EM, Cordat E, Caluseriu O. The novel p.Ser263Phe mutation in the human high-affinity choline transporter 1 (CHT1/SLC5A7) causes a lethal form of fetal akinesia syndrome. Hum Mutat 2019; 40:1676-1683. [PMID: 31299140 DOI: 10.1002/humu.23828] [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: 11/23/2018] [Revised: 05/04/2019] [Accepted: 05/27/2019] [Indexed: 11/07/2022]
Abstract
A subset of a larger and heterogeneous class of disorders, the congenital myasthenic syndromes (CMS) are caused by pathogenic variants in genes encoding proteins that support the integrity and function of the neuromuscular junction (NMJ). A central component of the NMJ is the sodium-dependent high-affinity choline transporter 1 (CHT1), a solute carrier protein (gene symbol SLC5A7), responsible for the reuptake of choline into nerve termini has recently been implicated as one of several autosomal recessive causes of CMS. We report the identification and functional characterization of a novel pathogenic variant in SLC5A7, c.788C>T (p.Ser263Phe) in an El Salvadorian family with a lethal form of a congenital myasthenic syndrome characterized by fetal akinesia. This study expands the clinical phenotype and insight into a form of fetal akinesia related to CHT1 defects and proposes a genotype-phenotype correlation for the lethal form of SLC5A7-related disorder with potential implications for genetic counseling.
Collapse
Affiliation(s)
- Mayukh Banerjee
- Department of Physiology and Membrane Protein Disease Research Group, University of Alberta, Edmonton, Alberta, Canada
| | - Denis Arutyunov
- Department of Physiology and Membrane Protein Disease Research Group, University of Alberta, Edmonton, Alberta, Canada
| | - Daniel Brandwein
- Department of Physiology and Membrane Protein Disease Research Group, University of Alberta, Edmonton, Alberta, Canada
| | | | - Hanna Kolski
- Department of Pediatrics, University of Alberta, Edmonton, Alberta, Canada
| | - Stacey Hume
- Department of Medical Genetics, University of Alberta, Edmonton, Alberta, Canada
| | - Norma Jean Leonard
- Department of Medical Genetics, University of Alberta, Edmonton, Alberta, Canada.,Department of Pediatrics, University of Alberta, Edmonton, Alberta, Canada
| | - James Watt
- Department of Pediatrics, University of Alberta, Edmonton, Alberta, Canada
| | - Atilano Lacson
- Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, Alberta, Canada
| | - Monica Baradi
- Department of Physiology and Membrane Protein Disease Research Group, University of Alberta, Edmonton, Alberta, Canada
| | - Elaine M Leslie
- Department of Physiology and Membrane Protein Disease Research Group, University of Alberta, Edmonton, Alberta, Canada.,Department of Laboratory Medicine and Pathology, University of Alberta, Edmonton, Alberta, Canada
| | - Emmanuelle Cordat
- Department of Physiology and Membrane Protein Disease Research Group, University of Alberta, Edmonton, Alberta, Canada
| | - Oana Caluseriu
- Department of Medical Genetics, University of Alberta, Edmonton, Alberta, Canada.,Department of Pediatrics, University of Alberta, Edmonton, Alberta, Canada
| |
Collapse
|
17
|
Muramatsu I, Uwada J, Yoshiki H, Sada K, Lee K, Yazawa T, Taniguchi T, Nishio M, Ishibashi T, Masuoka T. Novel regulatory systems for acetylcholine release in rat striatum and anti‐Alzheimer's disease drugs. J Neurochem 2019; 149:605-623. [DOI: 10.1111/jnc.14701] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Revised: 02/20/2019] [Accepted: 03/27/2019] [Indexed: 10/27/2022]
Affiliation(s)
- Ikunobu Muramatsu
- Department of Pharmacology School of Medicine Kanazawa Medical University Uchinada, Ishikawa Japan
- Division of Genomic Science and Microbiology School of Medicine University of Fukui Eiheiji Fukui Japan
- Kimura Hospital Awara Fukui Japan
| | - Junsuke Uwada
- Division of Cellular Signal Transduction Department of Biochemistry Asahikawa Medical University Asahikawa Hokkaido Japan
| | - Hatsumi Yoshiki
- Division of Genomic Science and Microbiology School of Medicine University of Fukui Eiheiji Fukui Japan
| | - Kiyonao Sada
- Division of Genomic Science and Microbiology School of Medicine University of Fukui Eiheiji Fukui Japan
| | - Kung‐Shing Lee
- Division of Genomic Science and Microbiology School of Medicine University of Fukui Eiheiji Fukui Japan
- Department of Surgery Kaohsiung Medical University Kaohsiung Taiwan
| | - Takashi Yazawa
- Division of Cellular Signal Transduction Department of Biochemistry Asahikawa Medical University Asahikawa Hokkaido Japan
| | - Takanobu Taniguchi
- Division of Cellular Signal Transduction Department of Biochemistry Asahikawa Medical University Asahikawa Hokkaido Japan
| | - Matomo Nishio
- Department of Pharmacology School of Medicine Kanazawa Medical University Uchinada, Ishikawa Japan
| | - Takaharu Ishibashi
- Department of Pharmacology School of Medicine Kanazawa Medical University Uchinada, Ishikawa Japan
| | - Takayoshi Masuoka
- Department of Pharmacology School of Medicine Kanazawa Medical University Uchinada, Ishikawa Japan
| |
Collapse
|
18
|
Sarter M, Phillips KB. The neuroscience of cognitive-motivational styles: Sign- and goal-trackers as animal models. Behav Neurosci 2018; 132:1-12. [PMID: 29355335 DOI: 10.1037/bne0000226] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Cognitive-motivational styles describe predominant patterns of processing or biases that broadly influence human cognition and performance. Here we focus on the impact of cognitive-motivational styles on the response to cues predicting the availability of food or addictive drugs. An individual may preferably conduct an analysis of the motivational significance of reward cues, with the result that such cues per se are perceived as rewarding and worth approaching and working for. Alternatively, a propensity for a "cold" analysis of the behavioral utility of a reward cue may yield search behavior for food or drugs but not involve cue approach. Animal models for studying the neuronal mechanisms mediating such styles have originated from research concerning behavioral indices that predict differential vulnerability to addiction-like behaviors. Rats classified as sign- or goal-trackers (STs, GTs) were found to have opposed attentional biases (bottom-up or cue-driven attention vs. top-down or goal-driven attentional control) that are mediated primarily via relatively unresponsive versus elevated levels of cholinergic neuromodulation in the cortex. The capacity for cholinergic neuromodulation in STs is limited by a neuronal choline transporter (CHT) that fails to support increases in cholinergic activity. Moreover, in contrast to STs, the frontal dopamine system in GTs does not respond to the presence of drug cues and, thus, biases against cue-oriented behavior. The opponent cognitive-motivational styles that are indexed by sign- and goal-tracking bestow different cognitive-behavioral vulnerabilities that may contribute to the manifestation of a wide range of neuropsychiatric disorders. (PsycINFO Database Record
Collapse
Affiliation(s)
- Martin Sarter
- Department of Psychology and Neuroscience Program, University of Michigan
| | - Kyra B Phillips
- Department of Psychology and Neuroscience Program, University of Michigan
| |
Collapse
|
19
|
Hemicholinium-3 sensitive choline transport in human T lymphocytes: Evidence for use as a proxy for brain choline transporter (CHT) capacity. Neurochem Int 2017; 108:410-416. [PMID: 28577989 DOI: 10.1016/j.neuint.2017.05.022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Revised: 05/26/2017] [Accepted: 05/30/2017] [Indexed: 02/06/2023]
Abstract
The synaptic uptake of choline via the high-affinity, hemicholinium-3-dependent choline transporter (CHT) strongly influences the capacity of cholinergic neurons to sustain acetylcholine (ACh) synthesis and release. To advance research on the impact of CHT capacity in humans, we established the presence of the neuronal CHT protein in human T lymphocytes. Next, we demonstrated CHT-mediated choline transport in human T cells. To address the validity of T cell-based choline uptake as a proxy for brain CHT capacity, we isolated T cells from the spleen, and synaptosomes from cortex and striatum, of wild type and CHT-overexpressing mice (CHT-OXP). Choline uptake capacity in T cells from CHT-OXP mice was two-fold higher than in wild type mice, mirroring the impact of CHT over-expression on synaptosomal CHT-mediated choline uptake. Monitoring T lymphocyte CHT protein and activity may be useful for estimating human CNS cholinergic capacity and for testing hypotheses concerning the contribution of CHT and, more generally, ACh signaling in cognition, neuroinflammation and disease.
Collapse
|
20
|
Kljakic O, Janickova H, Prado VF, Prado MAM. Cholinergic/glutamatergic co-transmission in striatal cholinergic interneurons: new mechanisms regulating striatal computation. J Neurochem 2017; 142 Suppl 2:90-102. [PMID: 28421605 DOI: 10.1111/jnc.14003] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Revised: 02/28/2017] [Accepted: 03/01/2017] [Indexed: 01/22/2023]
Abstract
It is well established that neurons secrete neuropeptides and ATP with classical neurotransmitters; however, certain neuronal populations are also capable of releasing two classical neurotransmitters by a process named co-transmission. Although there has been progress in our understanding of the molecular mechanism underlying co-transmission, the individual regulation of neurotransmitter secretion and the functional significance of this neuronal 'bilingualism' is still unknown. Striatal cholinergic interneurons (CINs) have been shown to secrete glutamate (Glu) in addition to acetylcholine (ACh) and are recognized for their role in the regulation of striatal circuits and behavior. Our review highlights the recent research into identifying mechanisms that regulate the secretion and function of Glu and ACh released by CINs and the roles these neurons play in regulating dopamine secretion and striatal activity. In particular, we focus on how the transporters for ACh (VAChT) and Glu (VGLUT3) influence the storage of neurotransmitters in CINs. We further discuss how these individual neurotransmitters regulate striatal computation and distinct aspects of behavior that are regulated by the striatum. We suggest that understanding the distinct and complementary functional roles of these two neurotransmitters may prove beneficial in the development of therapies for Parkinson's disease and addiction. Overall, understanding how Glu and ACh secreted by CINs impacts striatal activity may provide insight into how different populations of 'bilingual' neurons are able to develop sophisticated regulation of their targets by interacting with multiple receptors but also by regulating each other's vesicular storage. This is an article for the special issue XVth International Symposium on Cholinergic Mechanisms.
Collapse
Affiliation(s)
- Ornela Kljakic
- Robarts Research Institute, Schulich School of Medicine & Dentistry, University of Western Ontario, London, Ontario, Canada.,Department of Anatomy and Cell Biology, Schulich School of Medicine & Dentistry, University of Western Ontario, London, Ontario, Canada
| | - Helena Janickova
- Robarts Research Institute, Schulich School of Medicine & Dentistry, University of Western Ontario, London, Ontario, Canada
| | - Vania F Prado
- Robarts Research Institute, Schulich School of Medicine & Dentistry, University of Western Ontario, London, Ontario, Canada.,Department of Anatomy and Cell Biology, Schulich School of Medicine & Dentistry, University of Western Ontario, London, Ontario, Canada.,Department of Physiology and Pharmacology, Schulich School of Medicine & Dentistry, University of Western Ontario, London, Ontario, Canada
| | - Marco A M Prado
- Robarts Research Institute, Schulich School of Medicine & Dentistry, University of Western Ontario, London, Ontario, Canada.,Department of Anatomy and Cell Biology, Schulich School of Medicine & Dentistry, University of Western Ontario, London, Ontario, Canada.,Department of Physiology and Pharmacology, Schulich School of Medicine & Dentistry, University of Western Ontario, London, Ontario, Canada
| |
Collapse
|
21
|
Cholinergic circuits in cognitive flexibility. Neuroscience 2017; 345:130-141. [DOI: 10.1016/j.neuroscience.2016.09.013] [Citation(s) in RCA: 83] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Revised: 08/31/2016] [Accepted: 09/08/2016] [Indexed: 01/10/2023]
|
22
|
Choudhary P, Armstrong EJ, Jorgensen CC, Piotrowski M, Barthmes M, Torella R, Johnston SE, Maruyama Y, Janiszewski JS, Storer RI, Skerratt SE, Benn CL. Discovery of Compounds that Positively Modulate the High Affinity Choline Transporter. Front Mol Neurosci 2017; 10:40. [PMID: 28289374 PMCID: PMC5326799 DOI: 10.3389/fnmol.2017.00040] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Accepted: 02/03/2017] [Indexed: 01/09/2023] Open
Abstract
Cholinergic hypofunction is associated with decreased attention and cognitive deficits in the central nervous system in addition to compromised motor function. Consequently, stimulation of cholinergic neurotransmission is a rational therapeutic approach for the potential treatment of a variety of neurological conditions. High affinity choline uptake (HACU) into acetylcholine (ACh)-synthesizing neurons is critically mediated by the sodium- and pH-dependent high-affinity choline transporter (CHT, encoded by the SLC5A7 gene). This transporter is comparatively well-characterized but otherwise unexplored as a potential drug target. We therefore sought to identify small molecules that would enable testing of the hypothesis that positive modulation of CHT mediated transport would enhance activity-dependent cholinergic signaling. We utilized existing and novel screening techniques for their ability to reveal both positive and negative modulation of CHT using literature tools. A screening campaign was initiated with a bespoke compound library comprising both the Pfizer Chemogenomic Library (CGL) of 2,753 molecules designed specifically to help enable the elucidation of new mechanisms in phenotypic screens and 887 compounds from a virtual screening campaign to select molecules with field-based similarities to reported negative and positive allosteric modulators. We identified a number of previously unknown active and structurally distinct molecules that could be used as tools to further explore CHT biology or as a starting point for further medicinal chemistry.
Collapse
Affiliation(s)
| | | | | | | | | | | | | | - Yuya Maruyama
- Central Research Laboratory, Kissei Pharmaceutical Co., Ltd. Nagano, Japan
| | | | - R Ian Storer
- Pfizer, Worldwide Medicinal Chemistry Cambridge, UK
| | | | | |
Collapse
|
23
|
Unresponsive Choline Transporter as a Trait Neuromarker and a Causal Mediator of Bottom-Up Attentional Biases. J Neurosci 2017; 37:2947-2959. [PMID: 28193693 DOI: 10.1523/jneurosci.3499-16.2017] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2016] [Revised: 01/30/2017] [Accepted: 02/01/2017] [Indexed: 01/16/2023] Open
Abstract
Some rats [sign-trackers (STs)] are prone to attribute incentive salience to reward cues, which can manifest as a propensity to approach and contact pavlovian cues, and for addiction-like behavior. STs also exhibit poor attentional performance, relative to goal-trackers (GTs), which is associated with attenuated acetylcholine (ACh) levels in prefrontal cortex (Paolone et al., 2013). Here, we demonstrate a cellular mechanism, linked to ACh synthesis, that accounts for attenuated cholinergic capacity in STs. First, we found that electrical stimulation of the basal forebrain increased cortical choline transporter (CHT)-mediated choline transport in GTs, paralleled by a redistribution of CHTs to the synaptic plasma membrane. Neither increases in choline uptake nor translocation of CHTs occurred in STs. Second, and consistent with uptake/translocation alterations, STs demonstrated a reduced ability to support cortical ACh release in vivo compared with GTs after reverse-dialysis to elevate extracellular potassium levels. Third, rats were significantly more likely to develop sign-tracking behavior if treated systemically before pavlovian conditioned approach training with the CHT inhibitor VU6001221. Consistent with its proposed mechanisms, administration of VU6001221 attenuated potassium-evoked ACh levels in prefrontal cortex measured with in vivo microdialysis. We propose that loss of CHT-dependent activation of cortical cholinergic activity in STs degrades top-down executive control over behavior, producing a bias for bottom-up or stimulus-driven attention. Such an attentional bias contributes to nonadaptive reward processing and thus identifies a novel mechanism that can support psychopathology, including addiction.SIGNIFICANCE STATEMENT The vulnerability for addiction-like behavior has been associated with psychological traits, such as the propensity to attribute incentive salience to reward cues that is modeled in rats by sign-tracking behavior. Sign-trackers tend to approach and contact cues associated with reward, whereas their counterparts, the goal-trackers, have a preference for approaching the location of the reward. Here, we show that the capacity of presynaptic cholinergic synapses to respond to stimulation by elevating presynaptic choline uptake and releasing acetylcholine is attenuated in sign-trackers. Furthermore, pharmacological inhibition of choline transport induced sign-tracking behavior. Our findings suggest that reduced levels of cholinergic neuromodulation can mediate an attentional bias toward reward-related cues, thereby allowing such cues to exert relatively greater control over behavior.
Collapse
|
24
|
Pereira PA, Millner T, Vilela M, Sousa S, Cardoso A, Madeira MD. Nerve growth factor-induced plasticity in medial prefrontal cortex interneurons of aged Wistar rats. Exp Gerontol 2016; 85:59-70. [DOI: 10.1016/j.exger.2016.09.017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Revised: 08/04/2016] [Accepted: 09/20/2016] [Indexed: 01/03/2023]
|
25
|
Cholinergic genetics of visual attention: Human and mouse choline transporter capacity variants influence distractibility. ACTA ACUST UNITED AC 2016; 110:10-18. [PMID: 27404793 DOI: 10.1016/j.jphysparis.2016.07.001] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Revised: 07/07/2016] [Accepted: 07/08/2016] [Indexed: 11/20/2022]
Abstract
The basal forebrain cholinergic projection system to the cortex mediates essential aspects of visual attention performance, including the detection of cues and the response to performance challenges (top-down control of attention). Higher levels of top-down control are mediated via elevated levels of cholinergic neuromodulation. The neuronal choline transporter (CHT) strongly influences the synthesis and release of acetylcholine (ACh). As the capacity of the CHT to import choline into the neuron is a major, presynaptic determinant of cholinergic neuromodulation, we hypothesize that genetically-imposed CHT capacity variation impacts the balance of bottom-up versus top-down control of visual attention. Following a brief review of the cognitive concepts relevant for this hypothesis, we describe the key results from our research in mice and humans that possess genetically-imposed changes in choline uptake capacity. CHT subcapacity is associated with poor top-down attentional control and attenuated (cholinergic) activation of right frontal regions. Conversely, mice overexpressing the CHT, and humans expressing a CHT variant hypothesized to enhance choline transporter function, are relatively resistant to challenges of visual attention performance. Genetic or environmental modulation of CHT expression and function may be associated with vulnerabilities for cognitive disorders.
Collapse
|
26
|
Ennis EA, Blakely RD. Choline on the Move: Perspectives on the Molecular Physiology and Pharmacology of the Presynaptic Choline Transporter. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2016; 76:175-213. [PMID: 27288078 DOI: 10.1016/bs.apha.2016.03.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Genetic, biochemical, physiological, and pharmacological approaches have advanced our understanding of cholinergic biology for over 100 years. High-affinity choline uptake (HACU) was one of the last features of cholinergic signaling to be defined at a molecular level, achieved through the cloning of the choline transporter (CHT, SLC5A7). In retrospect, the molecular era of CHT studies initiated with the identification of hemicholinium-3 (HC-3), a potent, competitive CHT antagonist, though it would take another 30 years before HC-3, in radiolabeled form, was used by Joseph Coyle's laboratory to identify and monitor the dynamics of CHT proteins. Though HC-3 studies provided important insights into CHT distribution and regulation, another 15 years would pass before the structure of CHT genes and proteins were identified, a full decade after the cloning of most other neurotransmitter-associated transporters. The availability of CHT gene and protein probes propelled the development of cell and animal models as well as efforts to gain insights into how human CHT gene variation affects the risk for brain and neuromuscular disorders. Most recently, our group has pursued a broadening of CHT pharmacology, elucidating novel chemical structures that may serve to advance cholinergic diagnostics and medication development. Here we provide a short review of the transformation that has occurred in HACU research and how such advances may promote the development of novel therapeutics.
Collapse
Affiliation(s)
- E A Ennis
- Vanderbilt University School of Medicine, Nashville, TN, United States
| | - R D Blakely
- Vanderbilt University School of Medicine, Nashville, TN, United States.
| |
Collapse
|
27
|
Mock KL, Tillekeratne LMV, Kirchhoff JR. Synthesis and characterization of water soluble choline labeled cadmium selenide/zinc selenide/zinc sulfide luminescent quantum dots. INORG CHEM COMMUN 2015. [DOI: 10.1016/j.inoche.2015.07.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|
28
|
Nassenstein C, Wiegand S, Lips KS, Li G, Klein J, Kummer W. Cholinergic activation of the murine trachealis muscle via non-vesicular acetylcholine release involving low-affinity choline transporters. Int Immunopharmacol 2015; 29:173-80. [PMID: 26278668 DOI: 10.1016/j.intimp.2015.08.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Revised: 08/04/2015] [Accepted: 08/04/2015] [Indexed: 11/15/2022]
Abstract
In addition to quantal, vesicular release of acetylcholine (ACh), there is also non-quantal release at the motor endplate which is insufficient to evoke postsynaptic responses unless acetylcholinesterase (AChE) is inhibited. We here addressed potential non-quantal release in the mouse trachea by organ bath experiments and (immuno)histochemical methods. Electrical field stimulation (EFS) of nerve terminals elicited tracheal constriction that is largely due to ACh release. Classical enzyme histochemistry demonstrated acetylcholinesterase (AChE) activity in nerve fibers in the muscle and butyrylcholinesterase (BChE) activity in the smooth muscle cells. Acute inhibition of both esterases by eserine significantly raised tracheal tone which was fully sensitive to atropine. This effect was reduced, but not abolished, in AChE, but not in BChE gene-deficient mice. The eserine-induced increase in tracheal tone was unaffected by vesamicol (10(-5)M), an inhibitor of the vesicular acetylcholine transporter, and by corticosterone (10(-4)M), an inhibitor of organic cation transporters. Hemicholinium-3, in low concentrations an inhibitor of the high-affinity choline transporter-1 (CHT1), completely abrogated the eserine effects when applied in high concentrations (10(-4)M) pointing towards an involvement of low-affinity choline transporters. To evaluate the cellular sources of non-quantal ACh release in the trachea, expression of low-affinity choline transporter-like family (CTL1-5) was evaluated by RT-PCR analysis. Even though these transporters were largely abundant in the epithelium, denudation of airway epithelial cells had no effect on eserine-induced tracheal contraction, indicating a non-quantal release of ACh from non-epithelial sources in the airways. These data provide evidence for an epithelium-independent non-vesicular, non-quantal ACh release in the mouse trachea involving low-affinity choline transporters.
Collapse
Affiliation(s)
- Christina Nassenstein
- Institute for Anatomy and Cell Biology, Justus-Liebig-University, Universities of Giessen and Marburg Lung Center (UGMLC) and German Center for Lung Research (DZL), Excellence Cluster Cardio-Pulmonary System, 35385 Giessen, Germany.
| | - Silke Wiegand
- Institute for Anatomy and Cell Biology, Justus-Liebig-University, Universities of Giessen and Marburg Lung Center (UGMLC) and German Center for Lung Research (DZL), Excellence Cluster Cardio-Pulmonary System, 35385 Giessen, Germany
| | - Katrin S Lips
- Laboratory for Experimental Trauma Surgery, Justus-Liebig University Giessen, 35392 Giessen, Germany
| | - Guanfeng Li
- Department of Pharmacology, School of Pharmacy, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany
| | - Jochen Klein
- Department of Pharmacology, School of Pharmacy, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany
| | - Wolfgang Kummer
- Institute for Anatomy and Cell Biology, Justus-Liebig-University, Universities of Giessen and Marburg Lung Center (UGMLC) and German Center for Lung Research (DZL), Excellence Cluster Cardio-Pulmonary System, 35385 Giessen, Germany
| |
Collapse
|
29
|
Cuddy LK, Seah C, Pasternak SH, Rylett RJ. Differential regulation of the high-affinity choline transporter by wild-type and Swedish mutant amyloid precursor protein. J Neurochem 2015; 134:769-82. [DOI: 10.1111/jnc.13167] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Revised: 04/30/2015] [Accepted: 05/06/2015] [Indexed: 01/18/2023]
Affiliation(s)
- Leah K. Cuddy
- Molecular Medicine Research Group; Robarts Research Institute; London Ontario Canada
- Department of Physiology and Pharmacology; University of Western Ontario; London Ontario Canada
| | - Claudia Seah
- Molecular Medicine Research Group; Robarts Research Institute; London Ontario Canada
| | - Stephen H. Pasternak
- Molecular Medicine Research Group; Robarts Research Institute; London Ontario Canada
- Department of Physiology and Pharmacology; University of Western Ontario; London Ontario Canada
- Department of Clinical Neurological Sciences; Schulich School of Medicine & Dentistry; University of Western Ontario; London Ontario Canada
| | - Rebecca Jane Rylett
- Molecular Medicine Research Group; Robarts Research Institute; London Ontario Canada
- Department of Physiology and Pharmacology; University of Western Ontario; London Ontario Canada
| |
Collapse
|
30
|
Li D, Hérault K, Zylbersztejn K, Lauterbach MA, Guillon M, Oheim M, Ropert N. Astrocyte VAMP3 vesicles undergo Ca2+ -independent cycling and modulate glutamate transporter trafficking. J Physiol 2015; 593:2807-32. [PMID: 25864578 DOI: 10.1113/jp270362] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Accepted: 04/07/2015] [Indexed: 01/26/2023] Open
Abstract
KEY POINTS Mouse cortical astrocytes express VAMP3 but not VAMP2. VAMP3 vesicles undergo Ca(2+) -independent exo- and endocytotic cycling at the plasma membrane. VAMP3 vesicle traffic regulates the recycling of plasma membrane glutamate transporters. cAMP modulates VAMP3 vesicle cycling and glutamate uptake. ABSTRACT Previous studies suggest that small synaptic-like vesicles in astrocytes carry vesicle-associated vSNARE proteins, VAMP3 (cellubrevin) and VAMP2 (synaptobrevin 2), both contributing to the Ca(2+) -regulated exocytosis of gliotransmitters, thereby modulating brain information processing. Here, using cortical astrocytes taken from VAMP2 and VAMP3 knock-out mice, we find that astrocytes express only VAMP3. The morphology and function of VAMP3 vesicles were studied in cultured astrocytes at single vesicle level with stimulated emission depletion (STED) and total internal reflection fluorescence (TIRF) microscopies. We show that VAMP3 antibodies label small diameter (∼80 nm) vesicles and that VAMP3 vesicles undergo Ca(2+) -independent exo-endocytosis. We also show that this pathway modulates the surface expression of plasma membrane glutamate transporters and the glutamate uptake by astrocytes. Finally, using pharmacological and optogenetic tools, we provide evidence suggesting that the cytosolic cAMP level influences astrocytic VAMP3 vesicle trafficking and glutamate transport. Our results suggest a new role for VAMP3 vesicles in astrocytes.
Collapse
Affiliation(s)
- Dongdong Li
- CNRS UMR 8118, Paris, F-75006 France; Brain Physiology Laboratory, Saints-Pères Research in Neurosciences Federation, Université Paris Descartes, Sorbonne Paris Cité, 45 rue des Saints Pères, Paris, F-75006, France.,INSERM U603, Paris, F-75006 France; CNRS UMR 8154, Paris, F-75006 France, Neurophysiology and New Microscopies Laboratory, 45 rue des Saints Pères, Paris, F-75006, France
| | - Karine Hérault
- CNRS UMR 8118, Paris, F-75006 France; Brain Physiology Laboratory, Saints-Pères Research in Neurosciences Federation, Université Paris Descartes, Sorbonne Paris Cité, 45 rue des Saints Pères, Paris, F-75006, France
| | - Kathleen Zylbersztejn
- INSERM ERL U950, Paris, F-75013, France.,Université Paris Diderot, Sorbonne Paris Cité, Paris, F-75013, France.,CNRS, UMR 7592, Institut Jacques Monod, Paris, F-75013, France
| | - Marcel A Lauterbach
- Neurophotonics Laboratory, CNRS UMR 8250, Université Paris Descartes, Sorbonne Paris Cité, 45 rue des Saints Pères, Paris, F-75006, France
| | - Marc Guillon
- Neurophotonics Laboratory, CNRS UMR 8250, Université Paris Descartes, Sorbonne Paris Cité, 45 rue des Saints Pères, Paris, F-75006, France
| | - Martin Oheim
- CNRS UMR 8118, Paris, F-75006 France; Brain Physiology Laboratory, Saints-Pères Research in Neurosciences Federation, Université Paris Descartes, Sorbonne Paris Cité, 45 rue des Saints Pères, Paris, F-75006, France.,INSERM U603, Paris, F-75006 France; CNRS UMR 8154, Paris, F-75006 France, Neurophysiology and New Microscopies Laboratory, 45 rue des Saints Pères, Paris, F-75006, France
| | - Nicole Ropert
- CNRS UMR 8118, Paris, F-75006 France; Brain Physiology Laboratory, Saints-Pères Research in Neurosciences Federation, Université Paris Descartes, Sorbonne Paris Cité, 45 rue des Saints Pères, Paris, F-75006, France.,INSERM U603, Paris, F-75006 France; CNRS UMR 8154, Paris, F-75006 France, Neurophysiology and New Microscopies Laboratory, 45 rue des Saints Pères, Paris, F-75006, France
| |
Collapse
|
31
|
Abstract
This article summarizes molecular properties of the high-affinity choline transporter (CHT1) with reference to the historical background focusing studies performed in laboratories of the author. CHT1 is present on the presynaptic terminal of cholinergic neurons, and takes up choline which is the precursor of acetylcholine. The Na(+)-dependent uptake of choline by CHT1 is the rate-limiting step for synthesis of acetylcholine. CHT1 is the integral membrane protein with 13 transmembrane segments, belongs to the Na(+)/glucose co-transporter family (SLC5), and has 20-25% homology with members of this family. A single nucleotide polymorphism (SNP) for human CHT1 has been identified, which has a replacement from isoleucine to valine in the third transmembrane segment and shows the choline uptake activity of 50-60% as much as that of wild-type CHT1. The proportion of this SNP is high among Asians. Possible importance of choline diet for those with this SNP was discussed.
Collapse
Affiliation(s)
- Tatsuya Haga
- Tokyo University, 7-3-1 Hongo, Tokyo 113-8654, Japan
| |
Collapse
|
32
|
Dettmer J, Ursache R, Campilho A, Miyashima S, Belevich I, O'Regan S, Mullendore DL, Yadav SR, Lanz C, Beverina L, Papagni A, Schneeberger K, Weigel D, Stierhof YD, Moritz T, Knoblauch M, Jokitalo E, Helariutta Y. CHOLINE TRANSPORTER-LIKE1 is required for sieve plate development to mediate long-distance cell-to-cell communication. Nat Commun 2014; 5:4276. [PMID: 25008948 DOI: 10.1038/ncomms5276] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2013] [Accepted: 06/02/2014] [Indexed: 11/09/2022] Open
Abstract
Phloem, a plant tissue responsible for long-distance molecular transport, harbours specific junctions, sieve areas, between the conducting cells. To date, little is known about the molecular framework related to the biogenesis of these sieve areas. Here we identify mutations at the CHER1/AtCTL1 locus of Arabidopsis thaliana. The mutations cause several phenotypic abnormalities, including reduced pore density and altered pore structure in the sieve areas associated with impaired phloem function. CHER1 encodes a member of a poorly characterized choline transporter-like protein family in plants and animals. We show that CHER1 facilitates choline transport, localizes to the trans-Golgi network, and during cytokinesis is associated with the phragmoplast. Consistent with its function in the elaboration of the sieve areas, CHER1 has a sustained, polar localization in the forming sieve plates. Our results indicate that the regulation of choline levels is crucial for phloem development and conductivity in plants.
Collapse
Affiliation(s)
- Jan Dettmer
- 1] Cell Biology Division, Department of Biology, University of Erlangen-Nuremberg, 91058 Erlangen, Germany [2]
| | - Robertas Ursache
- 1] Institute of Biotechnology, Department of Biological and Environmental Sciences, University of Helsinki, Helsinki FIN-00014, Finland [2]
| | - Ana Campilho
- 1] Institute for Molecular and Cell Biology (IBMC), University of Porto, Porto 4150-180, Portugal [2]
| | - Shunsuke Miyashima
- Institute of Biotechnology, Department of Biological and Environmental Sciences, University of Helsinki, Helsinki FIN-00014, Finland
| | - Ilya Belevich
- Institute of Biotechnology, Department of Biological and Environmental Sciences, University of Helsinki, Helsinki FIN-00014, Finland
| | - Seana O'Regan
- Neurophotonics Laboratory, CNRS/Université Paris Descartes, 45, rue des Saints-Pères, 75270 Paris, France
| | - Daniel Leroy Mullendore
- School of Biological Sciences, Washington State University, Pullman, Washington 99164-4236, USA
| | - Shri Ram Yadav
- Institute of Biotechnology, Department of Biological and Environmental Sciences, University of Helsinki, Helsinki FIN-00014, Finland
| | - Christa Lanz
- Department of Molecular Biology, Max Planck Institute for Developmental Biology, 72076 Tuebingen, Germany
| | - Luca Beverina
- Department of Materials Science, University of Milano-Bicocca, Via R. Cozzi 55, 20125 Milano, Italy
| | - Antonio Papagni
- Department of Materials Science, University of Milano-Bicocca, Via R. Cozzi 55, 20125 Milano, Italy
| | - Korbinian Schneeberger
- Max Planck Institute for Plant Breeding Research, Department for Plant Developmental Biology, 50829 Cologne, Germany
| | - Detlef Weigel
- Department of Molecular Biology, Max Planck Institute for Developmental Biology, 72076 Tuebingen, Germany
| | - York-Dieter Stierhof
- ZMBP, Mikroskopie, Universität Tübingen, Auf der Morgenstelle 5, 72076 Tübingen, Germany
| | - Thomas Moritz
- Department of Forest Genetics and Plant Physiology, Umeå Plant Science Center, Swedish University of Agricultural Sciences, SE-90183 Umeå, Sweden
| | - Michael Knoblauch
- School of Biological Sciences, Washington State University, Pullman, Washington 99164-4236, USA
| | - Eija Jokitalo
- Institute of Biotechnology, Department of Biological and Environmental Sciences, University of Helsinki, Helsinki FIN-00014, Finland
| | - Ykä Helariutta
- Institute of Biotechnology, Department of Biological and Environmental Sciences, University of Helsinki, Helsinki FIN-00014, Finland
| |
Collapse
|
33
|
Drosophila melanogaster as a genetic model system to study neurotransmitter transporters. Neurochem Int 2014; 73:71-88. [PMID: 24704795 DOI: 10.1016/j.neuint.2014.03.015] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Revised: 03/20/2014] [Accepted: 03/24/2014] [Indexed: 12/30/2022]
Abstract
The model genetic organism Drosophila melanogaster, commonly known as the fruit fly, uses many of the same neurotransmitters as mammals and very similar mechanisms of neurotransmitter storage, release and recycling. This system offers a variety of powerful molecular-genetic methods for the study of transporters, many of which would be difficult in mammalian models. We review here progress made using Drosophila to understand the function and regulation of neurotransmitter transporters and discuss future directions for its use.
Collapse
|
34
|
Hartnett S, Zhang F, Abitz A, Li Y. Ubiquitin C-terminal hydrolase L1 interacts with choline transporter in cholinergic cells. Neurosci Lett 2014; 564:115-9. [PMID: 24525247 DOI: 10.1016/j.neulet.2014.02.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2013] [Revised: 01/27/2014] [Accepted: 02/02/2014] [Indexed: 02/02/2023]
Abstract
Ubiquitin carboxyl-terminal hydrolase L1 (UCHL1) is a deubiquitinating enzyme, which is highly expressed in neuronal cells. Previous studies have indicated that UCHL1 is involved in cognitive function, neurodegenerative diseases, and neuromuscular junction development. Acetylcholine (Ach) is a critical neurotransmitter in these functions. Yet, the effect of UCHL1 on the cholinergic system has not been reported. In this study, using a cholinergic neuronal cell line, SN56, as an invitro model, we detected the physical interaction of UCHL1 and high affinity choline transporter (CHT), which is a key protein regulating Ach re-synthesis. Reduction of UCHL1 by siRNA gene knockdown significantly increased poly-ubiquitinated CHT and decreased native CHT protein level, but did not affect CHT mRNA expression. Biotinylation assay showed that UCHL1 is localized only in the cytosol of the cells and that the gene knockdown of UCHL1 significantly reduced cytosolic CHT but had no significant effect on membrane CHT level. These data provide novel and potentially important evidence that UCHL1 may play a role in the regulation of cholinergic function by affecting CHT ubiquitination and degradation.
Collapse
Affiliation(s)
- Sigurd Hartnett
- Division of Basic Biomedical Sciences, Sanford School of Medicine, The University of South Dakota, Vermillion, SD, 57069, USA
| | - Fan Zhang
- Division of Basic Biomedical Sciences, Sanford School of Medicine, The University of South Dakota, Vermillion, SD, 57069, USA
| | - Allison Abitz
- Division of Basic Biomedical Sciences, Sanford School of Medicine, The University of South Dakota, Vermillion, SD, 57069, USA
| | - Yifan Li
- Division of Basic Biomedical Sciences, Sanford School of Medicine, The University of South Dakota, Vermillion, SD, 57069, USA.
| |
Collapse
|
35
|
Cuddy LK, Winick-Ng W, Rylett RJ. Regulation of the high-affinity choline transporter activity and trafficking by its association with cholesterol-rich lipid rafts. J Neurochem 2013; 128:725-40. [PMID: 24127780 DOI: 10.1111/jnc.12490] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Revised: 10/10/2013] [Accepted: 10/14/2013] [Indexed: 01/07/2023]
Abstract
The sodium-coupled, hemicholinium-3-sensitive, high-affinity choline transporter (CHT) is responsible for transport of choline into cholinergic nerve terminals from the synaptic cleft following acetylcholine release and hydrolysis. In this study, we address regulation of CHT function by plasma membrane cholesterol. We show for the first time that CHT is concentrated in cholesterol-rich lipid rafts in both SH-SY5Y cells and nerve terminals from mouse forebrain. Treatment of SH-SY5Y cells expressing rat CHT with filipin, methyl-β-cyclodextrin (MβC) or cholesterol oxidase significantly decreased choline uptake. In contrast, CHT activity was increased by addition of cholesterol to membranes using cholesterol-saturated MβC. Kinetic analysis of binding of [(3)H]hemicholinium-3 to CHT revealed that reducing membrane cholesterol with MβC decreased both the apparent binding affinity (KD) and maximum number of binding sites (Bmax ); this was confirmed by decreased plasma membrane CHT protein in lipid rafts in cell surface protein biotinylation assays. Finally, the loss of cell surface CHT associated with lipid raft disruption was not because of changes in CHT internalization. In summary, we provide evidence that CHT association with cholesterol-rich rafts is critical for transporter function and localization. Alterations in plasma membrane cholesterol cholinergic nerve terminals could diminish cholinergic transmission by reducing choline availability for acetylcholine synthesis. The sodium-coupled choline transporter CHT moves choline into cholinergic nerve terminals to serve as substrate for acetylcholine synthesis. We show for the first time that CHT is concentrated in cholesterol-rich lipid rafts, and decreasing membrane cholesterol significantly reduces both choline uptake activity and cell surface CHT protein levels. CHT association with cholesterol-rich rafts is critical for its function, and alterations in plasma membrane cholesterol could diminish cholinergic transmission by reducing choline availability for acetylcholine synthesis.
Collapse
Affiliation(s)
- Leah K Cuddy
- Molecular Brain Research Group, Robarts Research Institute, Department of Physiology and Pharmacology, Schulich School of Medicine & Dentistry, University of Western Ontario, London, Ontario, Canada
| | | | | |
Collapse
|
36
|
Paolone G, Mallory CS, Cherian AK, Miller TR, Blakely RD, Sarter M. Monitoring cholinergic activity during attentional performance in mice heterozygous for the choline transporter: a model of cholinergic capacity limits. Neuropharmacology 2013; 75:274-85. [PMID: 23958450 DOI: 10.1016/j.neuropharm.2013.07.032] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Revised: 07/23/2013] [Accepted: 07/30/2013] [Indexed: 01/07/2023]
Abstract
Reductions in the capacity of the human choline transporter (SLC5A7, CHT) have been hypothesized to diminish cortical cholinergic neurotransmission, leading to risk for cognitive and mood disorders. To determine the acetylcholine (ACh) release capacity of cortical cholinergic projections in a mouse model of cholinergic hypofunction, the CHT+/- mouse, we assessed extracellular ACh levels while mice performed an operant sustained attention task (SAT). We found that whereas SAT-performance-associated increases in extracellular ACh levels of CHT+/- mice were significantly attenuated relative to wildtype littermates, performance on the SAT was normal. Tetrodotoxin-induced blockade of neuronal excitability reduced both dialysate ACh levels and SAT performance similarly in both genotypes. Likewise, lesions of cholinergic neurons abolished SAT performance in both genotypes. However, cholinergic activation remained more vulnerable to the reverse-dialyzed muscarinic antagonist atropine in CHT+/- mice. Additionally, CHT+/- mice displayed greater SAT-disrupting effects of reverse dialysis of the nAChR antagonist mecamylamine. Receptor binding assays revealed a higher density of α4β2* nAChRs in the cortex of CHT+/- mice compared to controls. These findings reveal compensatory mechanisms that, in the context of moderate cognitive challenges, can overcome the performance deficits expected from the significantly reduced ACh capacity of CHT+/- cholinergic terminals. Further analyses of molecular and functional compensations in the CHT+/- model may provide insights into both risk and resiliency factors involved in cognitive and mood disorders.
Collapse
Affiliation(s)
- Giovanna Paolone
- Department of Psychology & Neuroscience Program, University of Michigan, Ann Arbor, MI 48103
| | - Caitlin S Mallory
- Department of Psychology & Neuroscience Program, University of Michigan, Ann Arbor, MI 48103
| | - Ajeesh Koshy Cherian
- Department of Psychology & Neuroscience Program, University of Michigan, Ann Arbor, MI 48103
| | - Thomas R Miller
- Neuroscience Discovery, AbbVie Inc., North Chicago, IL 60064
| | - Randy D Blakely
- Departments of Pharmacology and Psychiatry, Vanderbilt University, Nashville, TN 37232-8548
| | - Martin Sarter
- Department of Psychology & Neuroscience Program, University of Michigan, Ann Arbor, MI 48103
| |
Collapse
|
37
|
Nagy PM, Aubert I. B6eGFPChAT mice overexpressing the vesicular acetylcholine transporter exhibit spontaneous hypoactivity and enhanced exploration in novel environments. Brain Behav 2013; 3:367-83. [PMID: 24381809 PMCID: PMC3869679 DOI: 10.1002/brb3.139] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/27/2012] [Revised: 03/18/2013] [Accepted: 03/22/2013] [Indexed: 12/15/2022] Open
Abstract
Cholinergic innervation is extensive throughout the central and peripheral nervous systems. Among its many roles, the neurotransmitter acetylcholine (ACh) contributes to the regulation of motor function, locomotion, and exploration. Cholinergic deficits and replacement strategies have been investigated in neurodegenerative disorders, particularly in cases of Alzheimer's disease (AD). Focus has been on blocking acetylcholinesterase (AChE) and enhancing ACh synthesis to improve cholinergic neurotransmission. As a first step in evaluating the physiological effects of enhanced cholinergic function through the upregulation of the vesicular acetylcholine transporter (VAChT), we used the hypercholinergic B6eGFPChAT congenic mouse model that has been shown to contain multiple VAChT gene copies. Analysis of biochemical and behavioral paradigms suggest that modest increases in VAChT expression can have a significant effect on spontaneous locomotion, reaction to novel stimuli, and the adaptation to novel environments. These observations support the potential of VAChT as a therapeutic target to enhance cholinergic tone, thereby decreasing spontaneous hyperactivity and increasing exploration in novel environments.
Collapse
Affiliation(s)
- Paul M Nagy
- Brain Sciences, Biological Sciences, Sunnybrook Research Institute2075 Bayview Avenue, Toronto, Ontario, M4N 3M5, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto1 King's College Circle, Toronto, Ontario, M5S 1A8, Canada
| | - Isabelle Aubert
- Brain Sciences, Biological Sciences, Sunnybrook Research Institute2075 Bayview Avenue, Toronto, Ontario, M4N 3M5, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto1 King's College Circle, Toronto, Ontario, M5S 1A8, Canada
| |
Collapse
|
38
|
Song P, Rekow SS, Singleton CA, Sekhon HS, Dissen GA, Zhou M, Campling B, Lindstrom J, Spindel ER. Choline transporter-like protein 4 (CTL4) links to non-neuronal acetylcholine synthesis. J Neurochem 2013; 126:451-61. [PMID: 23651124 DOI: 10.1111/jnc.12298] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2013] [Revised: 05/03/2013] [Accepted: 05/06/2013] [Indexed: 01/26/2023]
Abstract
Synthesis of acetylcholine (ACh) by non-neuronal cells is now well established and plays diverse physiologic roles. In neurons, the Na(+) -dependent, high affinity choline transporter (CHT1) is absolutely required for ACh synthesis. In contrast, some non-neuronal cells synthesize ACh in the absence of CHT1 indicating a fundamental difference in ACh synthesis compared to neurons. The aim of this study was to identify choline transporters, other than CHT1, that play a role in non-neuronal ACh synthesis. ACh synthesis was studied in lung and colon cancer cell lines focusing on the choline transporter-like proteins, a five gene family choline-transporter like protein (CTL)1-5. Supporting a role for CTLs in choline transport in lung cancer cells, choline transport was Na(+) -independent and CTL1-5 were expressed in all cells examined. CTL1, 2, and 5 were expressed at highest levels and knockdown of CTL1, 2, and 5 decreased choline transport in H82 lung cancer cells. Knockdowns of CTL1, 2, 3, and 5 had no effect on ACh synthesis in H82 cells. In contrast, knockdown of CTL4 significantly decreased ACh secretion by both lung and colon cancer cells. Conversely, increasing expression of CTL4 increased ACh secretion. These results indicate that CTL4 mediates ACh synthesis in non-neuronal cell lines and presents a mechanism to target non-neuronal ACh synthesis without affecting neuronal ACh synthesis.
Collapse
Affiliation(s)
- Pingfang Song
- Division of Neuroscience, Oregon National Primate Research Center, Oregon Health & Science University, Beaverton, Oregon 97006, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
39
|
Lima CS, Dutra-Tavares AC, Nunes F, Nunes-Freitas AL, Ribeiro-Carvalho A, Filgueiras CC, Manhães AC, Meyer A, Abreu-Villaça Y. Methamidophos exposure during the early postnatal period of mice: immediate and late-emergent effects on the cholinergic and serotonergic systems and behavior. Toxicol Sci 2013; 134:125-39. [PMID: 23596261 DOI: 10.1093/toxsci/kft095] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Organophosphates (OPs) are among the most used pesticides. Although some OPs have had their use progressively more restricted, other OPs are being used without sufficient investigation of their effects. Here, we investigated the immediate neurochemical and delayed neurochemical and behavioral actions of the OP methamidophos to verify whether there are concerns regarding exposure during early postnatal development. From the third to the nineth postnatal day (PN), Swiss mice were sc injected with methamidophos (1mg/kg). At PN10, we assessed cholinergic and serotonergic biomarkers in the cerebral cortex and brainstem. From PN60 to PN63, mice were submitted to a battery of behavioral tests and subsequently to biochemical analyses. At PN10, the effects were restricted to females and to the cholinergic system: Methamidophos promoted increased choline transporter binding in the brainstem. At PN63, in the brainstem, there was a decrease in choline transporter, a female-only decrease in 5HT1A and a male-only increase in 5HT2 receptor binding. In the cortex, choline acetyltransferase activity was decreased and 5HT2 receptor binding was increased both in males and females. Methamidophos elicited behavioral alterations, suggestive of increased depressive-like behavior and impaired decision making. There were no significant alterations on anxiety-related measures and on memory/learning. Methamidophos elicited cholinergic and serotonergic alterations that depended on brain region, sex, and age of the animals. These outcomes, together with the behavioral effects, indicate that this OP is deleterious to the developing brain and that alterations are indeed identified long after the end of exposure.
Collapse
Affiliation(s)
- Carla S Lima
- Departamento de Ciências Fisiológicas, Universidade do Estado do Rio de Janeiro, Rio de Janeiro, Brazil
| | | | | | | | | | | | | | | | | |
Collapse
|
40
|
Abstract
Acetylcholine, the first chemical to be identified as a neurotransmitter, is packed in synaptic vesicles by the activity of VAChT (vesicular acetylcholine transporter). A decrease in VAChT expression has been reported in a number of diseases, and this has consequences for the amount of acetylcholine loaded in synaptic vesicles as well as for neurotransmitter release. Several genetically modified mice targeting the VAChT gene have been generated, providing novel models to understand how changes in VAChT affect transmitter release. A surprising finding is that most cholinergic neurons in the brain also can express a second type of vesicular neurotransmitter transporter that allows these neurons to secrete two distinct neurotransmitters. Thus a given neuron can use two neurotransmitters to regulate different physiological functions. In addition, recent data indicate that non-neuronal cells can also express the machinery used to synthesize and release acetylcholine. Some of these cells rely on VAChT to secrete acetylcholine with potential physiological consequences in the periphery. Hence novel functions for the oldest neurotransmitter known are emerging with the potential to provide new targets for the treatment of several pathological conditions.
Collapse
|
41
|
The presynaptic choline transporter imposes limits on sustained cortical acetylcholine release and attention. J Neurosci 2013; 33:2326-37. [PMID: 23392663 DOI: 10.1523/jneurosci.4993-12.2013] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Functional variation in the gene encoding the presynaptic choline transporter (CHT) has been linked to attention-deficit/hyperactivity disorder. Here, we report that a heterozygous deletion in the CHT gene in mice (CHT(+/-)) limits the capacity of cholinergic neurons to sustain acetylcholine (ACh) release and attentional performance. Cortical microdialysis and amperometric methods revealed that, whereas wild-type and CHT(+/-) animals support equivalent basal ACh release and choline clearance, CHT(+/-) animals exhibit a significant inability to elevate extracellular ACh following basal forebrain stimulation, in parallel with a diminished choline clearance capacity following cessation of stimulation. Consistent with these findings, the density of CHTs in cortical synaptosomal plasma membrane-enriched fractions from unstimulated CHT(+/-) animals matched those observed in wild-type animals despite reductions in CHT levels in total extracts, achieved via a redistribution of CHT from vesicle pools. As a consequence, in CHT(+/-) animals, basal forebrain stimulation was unable to mobilize wild-type quantities of CHT to the plasma membrane. In behavioral studies, CHT(+/-) mice were impaired in performing a sustained attention task known to depend on cortical cholinergic activity. In wild-type mice, but not CHT(+/-) mice, attentional performance increased the density of CHTs in the synaptosomal membrane in the right frontal cortex. Basal CHT levels in vesicle-enriched membranes predicted the degree of CHT mobilization as well as individual variations in performance on the sustained attention task. Our findings demonstrate biochemical and physiological alterations that underlie cognitive impairments associated with genetically imposed reductions in choline uptake capacity.
Collapse
|
42
|
Metaxas A, Keyworth H, Yoo J, Chen Y, Kitchen I, Bailey A. The stereotypy-inducing and OCD-like effects of chronic 'binge' cocaine are modulated by distinct subtypes of nicotinic acetylcholine receptors. Br J Pharmacol 2013; 167:450-64. [PMID: 22568685 DOI: 10.1111/j.1476-5381.2012.02023.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND AND PURPOSE High rates of cigarette smoking occur in cocaine-dependent individuals, reflecting an involvement of nicotinic acetylcholine receptors (nAChRs) in cocaine-elicited behaviour. This study was designed to assess the contribution of different nAChR subtypes to the behavioural and neurochemical effects of chronic cocaine treatment. EXPERIMENTAL APPROACH Cocaine (15 mg·kg(-1) , i.p.) was administered to male C57BL/6J mice in a chronic 'binge' paradigm, with and without the coadministration of the α7 preferring nAChR antagonist methyllycaconitine (MLA; 5 mg·kg(-1) , i.p.) or the β2* nAChR antagonist dihydro-β-erythroidine (DHβE; 2 mg·kg(-1) , i.p.). Quantitative autoradiography was used to examine the effect of cocaine exposure on α7 and α4β2* nAChRs, and on the high-affinity choline transporter. KEY RESULTS MLA+cocaine administration induced an intense self-grooming behaviour, indicating a likely role for α7 nAChRs in modulating this anxiogenic, compulsive-like effect of cocaine. In the major island of Calleja, a key area of action for neuroleptics, MLA+cocaine reduced choline transporter binding compared with cocaine (with or without DHβE) administration. DHβE treatment prevented the induction of stereotypy sensitisation to cocaine but prolonged locomotor sensitisation, implicating heteromeric β2* nAChRs in the neuroadaptations mediating cocaine-induced behavioural sensitisation. 'Binge' cocaine treatment region-specifically increased α4β2* nAChR binding in the midbrain dopaminergic regions: ventral tegmental area and substantia nigra pars compacta. CONCLUSIONS AND IMPLICATIONS We have shown a differential, subtype-selective, contribution of nAChRs to the behavioural and neurochemical sequelae of chronic cocaine administration. These data support the clinical utility of targeting specific nAChR subtypes for the alleviation of cocaine-abuse symptomatology.
Collapse
Affiliation(s)
- A Metaxas
- Department of Biochemistry and Physiology, Faculty of Health and Medical Sciences, Institute of Health and Medical Sciences, University of Surrey, Guildford, UK.
| | | | | | | | | | | |
Collapse
|
43
|
Okuda T, Osawa C, Yamada H, Hayashi K, Nishikawa S, Ushio T, Kubo Y, Satou M, Ogawa H, Haga T. Transmembrane topology and oligomeric structure of the high-affinity choline transporter. J Biol Chem 2012; 287:42826-34. [PMID: 23132865 DOI: 10.1074/jbc.m112.405027] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The high-affinity choline transporter CHT1 mediates choline uptake essential for acetylcholine synthesis in cholinergic nerve terminals. CHT1 belongs to the Na(+)/glucose cotransporter family (SLC5), which is postulated to have a common 13-transmembrane domain core; however, no direct experimental evidence for CHT1 transmembrane topology has yet been reported. We examined the transmembrane topology of human CHT1 using cysteine-scanning analysis. Single cysteine residues were introduced into the putative extra- and intracellular loops and probed for external accessibility for labeling with a membrane-impermeable, sulfhydryl-specific biotinylating reagent in intact cells expressing these mutants. The results provide experimental evidence for a topological model of a 13-transmembrane domain protein with an extracellular amino terminus and an intracellular carboxyl terminus. We also constructed a three-dimensional homology model of CHT1 based on the crystal structure of the bacterial Na(+)/galactose cotransporter, which supports our conclusion of CHT1 transmembrane topology. Furthermore, we examined whether CHT1 exists as a monomer or oligomer. Chemical cross-linking induces the formation of a higher molecular weight form of CHT1 on the cell surface in HEK293 cells. Two different epitope-tagged CHT1 proteins expressed in the same cells can be co-immunoprecipitated. Moreover, co-expression of an inactive mutant I89A with the wild type induces a dominant-negative effect on the overall choline uptake activity. These results indicate that CHT1 forms a homo-oligomer on the cell surface in cultured cells.
Collapse
Affiliation(s)
- Takashi Okuda
- Department of Pharmacology, Faculty of Pharmacy, Keio University, 1-5-30 Shibakoen, Minato-ku, Tokyo, Japan.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
44
|
De Jaeger X, Cammarota M, Prado MAM, Izquierdo I, Prado VF, Pereira GS. Decreased acetylcholine release delays the consolidation of object recognition memory. Behav Brain Res 2012; 238:62-8. [PMID: 23089649 DOI: 10.1016/j.bbr.2012.10.016] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2012] [Revised: 09/18/2012] [Accepted: 10/11/2012] [Indexed: 10/27/2022]
Abstract
Acetylcholine (ACh) is important for different cognitive functions such as learning, memory and attention. The release of ACh depends on its vesicular loading by the vesicular acetylcholine transporter (VAChT). It has been demonstrated that VAChT expression can modulate object recognition memory. However, the role of VAChT expression on object recognition memory persistence still remains to be understood. To address this question we used distinct mouse lines with reduced expression of VAChT, as well as pharmacological manipulations of the cholinergic system. We showed that reduction of cholinergic tone impairs object recognition memory measured at 24h. Surprisingly, object recognition memory, measured at 4 days after training, was impaired by substantial, but not moderate, reduction in VAChT expression. Our results suggest that levels of acetylcholine release strongly modulate object recognition memory consolidation and appear to be of particular importance for memory persistence 4 days after training.
Collapse
Affiliation(s)
- Xavier De Jaeger
- Molecular Brain Research Group, Robarts Research Institute, Schulich School of Medicine & Dentistry, University of Western Ontario, London, Ontario, N6A 5K8 Canada.
| | | | | | | | | | | |
Collapse
|
45
|
Peroxynitrite donor SIN-1 alters high-affinity choline transporter activity by modifying its intracellular trafficking. J Neurosci 2012; 32:5573-84. [PMID: 22514319 DOI: 10.1523/jneurosci.5235-11.2012] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Sodium-coupled, high-affinity choline transporters (CHTs) are inhibited by 3-morpholinosydnonimine (SIN-1) [peroxynitrite (ONOO⁻) donor]; ONOO⁻ can be produced from nitric oxide and reactive oxygen species during neurodegeneration. SIN-1 rapidly increases CHT internalization from the cell surface, and this correlates with decreased choline uptake. This study addresses mechanisms by which SIN-1 inhibits CHT function in human neuronal SH-SY5Y cells. Thus, mutant L531A-CHT, which does not constitutively internalize into cells by a clathrin-mediated process, is resistant to SIN-1 effects. This suggests that CHT inhibition is not due to oxidative-nitrosative inactivation of the protein and that decreased levels of cell surface CHT in SIN-1-treated cells is related to alterations in its trafficking and subcellular disposition. Dominant-negative proteins AP180C and dynamin-K44A, which interfere with clathrin-mediated and dynamin-dependent endocytosis, respectively, attenuate CHT inhibition by SIN-1. CHT in both vehicle- and SIN-1-treated cells colocalizes with Rab7, Rab9, and Lamp-1 in late endosomes and lysosomes to a similar extent. Lysosome inhibitors increase choline uptake, suggesting that CHT proteins are normally degraded by lysosomes, and this is not altered by oxidative stress. Unexpectedly, inhibitors of proteasomes, but not lysosomes, attenuate SIN-1-mediated inhibition of choline uptake, indicating that proteasomal degradation plays a role in regulating CHT disposition in SIN-1-treated cells. SIN-1 treatment also enhances CHT ubiquitination. Thus, CHT inhibition in SIN-1-treated cells is mediated by proteasomal degradation, which differs from inhibitory mechanisms for some neurotransmitter transporters under similar conditions. Increased oxidative-nitrosative stress in the microenvironment of cholinergic nerve terminals would diminish cholinergic transmission by reducing choline availability for ACh synthesis.
Collapse
|
46
|
Rocha-Resende C, Roy A, Resende R, Ladeira MS, Lara A, de Morais Gomes ER, Prado VF, Gros R, Guatimosim C, Prado MAM, Guatimosim S. Non-neuronal cholinergic machinery present in cardiomyocytes offsets hypertrophic signals. J Mol Cell Cardiol 2012; 53:206-16. [PMID: 22587993 DOI: 10.1016/j.yjmcc.2012.05.003] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2012] [Revised: 04/17/2012] [Accepted: 05/03/2012] [Indexed: 12/19/2022]
Abstract
Recent work has provided compelling evidence that increased levels of acetylcholine (ACh) can be protective in heart failure, whereas reduced levels of ACh secretion can cause heart malfunction. Previous data show that cardiomyocytes themselves can actively secrete ACh, raising the question of whether this cardiomyocyte derived ACh may contribute to the protective effects of ACh in the heart. To address the functionality of this non-neuronal ACh machinery, we used cholinesterase inhibitors and a siRNA targeted to AChE (acetylcholinesterase) as a way to increase the availability of ACh secreted by cardiac cells. By using nitric oxide (NO) formation as a biological sensor for released ACh, we showed that cholinesterase inhibition increased NO levels in freshly isolated ventricular myocytes and that this effect was prevented by atropine, a muscarinic receptor antagonist, and by inhibition of ACh synthesis or vesicular storage. Functionally, cholinesterase inhibition prevented the hypertrophic effect as well as molecular changes and calcium transient alterations induced by adrenergic overstimulation in cardiomyocytes. Moreover, inhibition of ACh storage or atropine blunted the anti-hypertrophic action of cholinesterase inhibition. Altogether, our results show that cardiomyocytes possess functional cholinergic machinery that offsets deleterious effects of hyperadrenergic stimulation. In addition, we show that adrenergic stimulation upregulates expression levels of cholinergic components. We propose that this cardiomyocyte cholinergic signaling could amplify the protective effects of the parasympathetic nervous system in the heart and may counteract or partially neutralize hypertrophic adrenergic effects.
Collapse
Affiliation(s)
- Cibele Rocha-Resende
- Department of Physiology and Biophysics, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, MG, CEP 31270-901, Brazil.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
47
|
Abreu BJ, Leite LF, Oliveira DL, Amaral E. Synaptic vesicle cycling is not impaired in a glutamatergic and a cholinergic synapse that exhibit deficits in acidification and filling. BRAZ J PHARM SCI 2012. [DOI: 10.1590/s1984-82502012000100017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The purpose of the present work was to investigate synaptic vesicle trafficking when vesicles exhibit alterations in filling and acidification in two different synapses: a cholinergic frog neuromuscular junction and a glutamatergic ribbon-type nerve terminal in the retina. These synapses display remarkable structural and functional differences, and the mechanisms regulating synaptic vesicle cycling might also differ between them. The lipophilic styryl dye FM1-43 was used to monitor vesicle trafficking. Both preparations were exposed to pharmacological agents that collapse ΔpH (NH4Cl and methylamine) or the whole ΔµH+ (bafilomycin), a necessary situation to provide the driving force for neurotransmitter accumulation into synaptic vesicles. The results showed that FM1-43 loading and unloading in neuromuscular junctions did not differ statistically between control and experimental conditions (P > 0.05). Also, FM1-43 labeling in bipolar cell terminals proved highly similar under all conditions tested. Despite remarkable differences in both experimental models, the present findings show that acidification and filling are not required for normal vesicle trafficking in either synapse.
Collapse
|
48
|
Elimination of the vesicular acetylcholine transporter in the striatum reveals regulation of behaviour by cholinergic-glutamatergic co-transmission. PLoS Biol 2011; 9:e1001194. [PMID: 22087075 PMCID: PMC3210783 DOI: 10.1371/journal.pbio.1001194] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2011] [Accepted: 09/29/2011] [Indexed: 11/30/2022] Open
Abstract
A novel mouse model that eliminates cholinergic neurotransmission in the striatum while leaving glutamate release intact reveals differential effects on cocaine-induced behavior and dopaminergic responses. Cholinergic neurons in the striatum are thought to play major regulatory functions in motor behaviour and reward. These neurons express two vesicular transporters that can load either acetylcholine or glutamate into synaptic vesicles. Consequently cholinergic neurons can release both neurotransmitters, making it difficult to discern their individual contributions for the regulation of striatal functions. Here we have dissected the specific roles of acetylcholine release for striatal-dependent behaviour in mice by selective elimination of the vesicular acetylcholine transporter (VAChT) from striatal cholinergic neurons. Analysis of several behavioural parameters indicates that elimination of VAChT had only marginal consequences in striatum-related tasks and did not affect spontaneous locomotion, cocaine-induced hyperactivity, or its reward properties. However, dopaminergic sensitivity of medium spiny neurons (MSN) and the behavioural outputs in response to direct dopaminergic agonists were enhanced, likely due to increased expression/function of dopamine receptors in the striatum. These observations indicate that previous functions attributed to striatal cholinergic neurons in spontaneous locomotor activity and in the rewarding responses to cocaine are mediated by glutamate and not by acetylcholine release. Our experiments demonstrate how one population of neurons can use two distinct neurotransmitters to differentially regulate a given circuitry. The data also raise the possibility of using VAChT as a target to boost dopaminergic function and decrease high striatal cholinergic activity, common neurochemical alterations in individuals affected with Parkinson's disease. The neurotransmitters dopamine and acetylcholine play opposite roles in the striatum (a brain region involved in motor control and reward-related behaviour), and their balance is thought to be critical for striatal function. Acetylcholine in the striatum has been linked to a number of functions, including control of locomotor activity and response to drugs of abuse. However, striatal cholinergic interneurons can also release glutamate (in addition to acetylcholine) and it is presently unclear how these two neurotransmitters regulate striatal-dependent behaviour. Previous work has attempted to resolve this issue by ablating cholinergic neurons in the striatum, but this causes loss of both cholinergic and glutamatergic neurotransmission. In this study, we created a novel genetic mouse model which allowed us to selectively interfere with secretion of acetylcholine in the striatum, while leaving total striatal glutamate release intact. In these mice, we observed minimally altered behavioural responses to cocaine, suggesting that striatal glutamate, rather than acetylcholine, is critical for cocaine-induced behavioural manifestations. Furthermore, elimination of striatal acetylcholine release affects how striatal output neurons respond to dopamine, by up-regulating dopaminergic receptors and changing behavioural responses to dopaminergic agonists. Our experiments highlight a previously unappreciated physiological role of cholinergic-glutamatergic co-transmission and demonstrate how a population of neurons can use two distinct neurotransmitters to differentially regulate behaviour.
Collapse
|
49
|
Schirmer SU, Eckhardt I, Lau H, Klein J, DeGraaf YC, Lips KS, Pineau C, Gibbins IL, Kummer W, Meinhardt A, Haberberger RV. The cholinergic system in rat testis is of non-neuronal origin. Reproduction 2011; 142:157-66. [DOI: 10.1530/rep-10-0302] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The cholinergic system consists of acetylcholine (ACh), its synthesising enzyme, choline acetyltransferase (CHAT), transporters such as the high-affinity choline transporter (SLC5A7; also known as ChT1), vesicular ACh transporter (SLC18A3; also known as VAChT), organic cation transporters (SLC22s; also known as OCTs), the nicotinic ACh receptors (CHRN; also known as nAChR) and muscarinic ACh receptors. The cholinergic system is not restricted to neurons but plays an important role in the structure and function of non-neuronal tissues such as epithelia and the immune system. Using molecular and immunohistochemical techniques, we show in this study that non-neuronal cells in the parenchyma of rat testis express mRNAs forChat,Slc18a3,Slc5a7andSlc22a2as well as for the CHRN subunits in locations completely lacking any form of innervation, as demonstrated by the absence of protein gene product 9.5 labelling. We found differentially expressed mRNAs for eight α and three β subunits of CHRN in testis. Expression of the α7-subunit of CHRN was widespread in spermatogonia, spermatocytes within seminiferous tubules as well as within Sertoli cells. Spermatogonia and spermatocytes also expressed the α4-subunit of CHRN. The presence of ACh in testicular parenchyma (TP), capsule and isolated germ cells could be demonstrated by HPLC. Taken together, our results reveal the presence of a non-neuronal cholinergic system in rat TP suggesting a potentially important role for non-neuronal ACh and its receptors in germ cell differentiation.
Collapse
|
50
|
Capettini SB, Moraes MF, Prado VF, Prado MA, Pereira GS. Vesicular acetylcholine transporter knock-down mice show sexual dimorphism on memory. Brain Res Bull 2011; 85:54-7. [DOI: 10.1016/j.brainresbull.2011.02.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2010] [Revised: 02/04/2011] [Accepted: 02/07/2011] [Indexed: 11/16/2022]
|