1
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Yoshida K, Kato D, Sugio S, Takeda I, Wake H. Activity-dependent oligodendrocyte calcium dynamics and their changes in Alzheimer's disease. Front Cell Neurosci 2023; 17:1154196. [PMID: 38026691 PMCID: PMC10644703 DOI: 10.3389/fncel.2023.1154196] [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: 01/30/2023] [Accepted: 10/11/2023] [Indexed: 12/01/2023] Open
Abstract
Oligodendrocytes (OCs) form myelin around axons, which is dependent on neuronal activity. This activity-dependent myelination plays a crucial role in training and learning. Previous studies have suggested that neuronal activity regulates proliferation and differentiation of oligodendrocyte precursor cells (OPCs) and myelination. In addition, deficient activity-dependent myelination results in impaired motor learning. However, the functional response of OC responsible for neuronal activity and their pathological changes is not fully elucidated. In this research, we aimed to understand the activity-dependent OC responses and their different properties by observing OCs using in vivo two-photon microscopy. We clarified that the Ca2+ activity in OCs is neuronal activity dependent and differentially regulated by neurotransmitters such as glutamate or adenosine triphosphate (ATP). Furthermore, in 5-month-old mice models of Alzheimer's disease, a period before the appearance of behavioral abnormalities, the elevated Ca2+ responses in OCs are ATP dependent, suggesting that OCs receive ATP from damaged tissue. We anticipate that our research will help in determining the correct therapeutic strategy for neurodegenerative diseases beyond the synapse.
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Affiliation(s)
- Kenji Yoshida
- Department of Anatomy and Molecular Cell Biology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Daisuke Kato
- Department of Anatomy and Molecular Cell Biology, Nagoya University Graduate School of Medicine, Nagoya, Japan
- Division of Multicellular Circuit Dynamics, National Institute for Physiological Sciences, National Institute of Natural Sciences, Okazaki, Japan
| | - Shouta Sugio
- Department of Anatomy and Molecular Cell Biology, Nagoya University Graduate School of Medicine, Nagoya, Japan
- Division of Multicellular Circuit Dynamics, National Institute for Physiological Sciences, National Institute of Natural Sciences, Okazaki, Japan
| | - Ikuko Takeda
- Department of Anatomy and Molecular Cell Biology, Nagoya University Graduate School of Medicine, Nagoya, Japan
- Division of Multicellular Circuit Dynamics, National Institute for Physiological Sciences, National Institute of Natural Sciences, Okazaki, Japan
| | - Hiroaki Wake
- Department of Anatomy and Molecular Cell Biology, Nagoya University Graduate School of Medicine, Nagoya, Japan
- Division of Multicellular Circuit Dynamics, National Institute for Physiological Sciences, National Institute of Natural Sciences, Okazaki, Japan
- Core Research for Evolutional Science and Technology, Japan Science and Technology Agency, Saitama, Japan
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2
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Li H. Rapid Isolation of Functional Synaptic Vesicles from Tissues Through Cryogrinding, Ultracentrifugation, and Size Exclusion Chromatography. Methods Mol Biol 2022; 2417:121-130. [PMID: 35099796 DOI: 10.1007/978-1-0716-1916-2_10] [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] [Indexed: 06/14/2023]
Abstract
Many biochemical and biophysical related questions require the isolation of functional synaptic vesicles. Isolated synaptic vesicles can be used for transporter kinetics studies, synaptic vesicle content analysis and immuno-labeling of specific synaptic vesicle proteins, etc. Here I describe a fast and reliable isolation procedure to allow researchers to isolate a large amount, as well as physiologically functional synaptic vesicles, by following the subsequent order of cryogrinding, gradient ultracentrifugation, and size exclusion liquid chromatography. This process enriches over 90% of the synaptic vesicle population, with low contamination of Golgi or endoplasmic reticulum vesicles.
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Affiliation(s)
- Huinan Li
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, CA, USA.
- Laboratory for Genomics Research, University of California San Francisco, San Francisco, CA, USA.
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3
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Reyes-Pinto R, Ferrán JL, Vega-Zuniga T, González-Cabrera C, Luksch H, Mpodozis J, Puelles L, Marín GJ. Change in the neurochemical signature and morphological development of the parvocellular isthmic projection to the avian tectum. J Comp Neurol 2021; 530:553-573. [PMID: 34363623 DOI: 10.1002/cne.25229] [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: 05/04/2021] [Revised: 07/27/2021] [Accepted: 07/30/2021] [Indexed: 11/05/2022]
Abstract
Neurons can change their classical neurotransmitters during ontogeny, sometimes going through stages of dual release. Here, we explored the development of the neurotransmitter identity of neurons of the avian nucleus isthmi parvocellularis (Ipc), whose axon terminals are retinotopically arranged in the optic tectum (TeO) and exert a focal gating effect upon the ascending transmission of retinal inputs. Although cholinergic and glutamatergic markers are both found in Ipc neurons and terminals of adult pigeons and chicks, the mRNA expression of the vesicular acetylcholine transporter, VAChT, is weak or absent. To explore how the Ipc neurotransmitter identity is established during ontogeny, we analyzed the expression of mRNAs coding for cholinergic (ChAT, VAChT, and CHT) and glutamatergic (VGluT2 and VGluT3) markers in chick embryos at different developmental stages. We found that between E12 and E18, Ipc neurons expressed all cholinergic mRNAs and also VGluT2 mRNA; however, from E16 through posthatch stages, VAChT mRNA expression was specifically diminished. Our ex vivo deposits of tracer crystals and intracellular filling experiments revealed that Ipc axons exhibit a mature paintbrush morphology late in development, experiencing marked morphological transformations during the period of presumptive dual vesicular transmitter release. Additionally, although ChAT protein immunoassays increasingly label the growing Ipc axon, this labeling was consistently restricted to sparse portions of the terminal branches. Combined, these results suggest that the synthesis of glutamate and acetylcholine, and their vesicular release, is complexly linked to the developmental processes of branching, growing and remodeling of these unique axons.
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Affiliation(s)
- Rosana Reyes-Pinto
- Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - José L Ferrán
- Department of Human Anatomy and Psychobiology and IMIB-Arrixaca Institute, University of Murcia, Murcia, Spain
| | - Tomas Vega-Zuniga
- Lehrstuhl für Zoologie, Technical University of Munich, Freising, Germany.,Institute of Science and Technology Austria (IST Austria), Klosterneuburg, Austria
| | | | - Harald Luksch
- Lehrstuhl für Zoologie, Technical University of Munich, Freising, Germany
| | - Jorge Mpodozis
- Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile
| | - Luis Puelles
- Department of Human Anatomy and Psychobiology and IMIB-Arrixaca Institute, University of Murcia, Murcia, Spain
| | - Gonzalo J Marín
- Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Santiago, Chile.,Facultad de Medicina, Universidad Finis Terrae, Santiago, Chile
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4
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Hoy KC, Strain MM, Turtle JD, Lee KH, Huie JR, Hartman JJ, Tarbet MM, Harlow ML, Magnuson DSK, Grau JW. Evidence That the Central Nervous System Can Induce a Modification at the Neuromuscular Junction That Contributes to the Maintenance of a Behavioral Response. J Neurosci 2020; 40:9186-9209. [PMID: 33097637 PMCID: PMC7687054 DOI: 10.1523/jneurosci.2683-19.2020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Revised: 10/13/2020] [Accepted: 10/14/2020] [Indexed: 11/21/2022] Open
Abstract
Neurons within the spinal cord are sensitive to environmental relations and can bring about a behavioral modification without input from the brain. For example, rats that have undergone a thoracic (T2) transection can learn to maintain a hind leg in a flexed position to minimize exposure to a noxious electrical stimulation (shock). Inactivating neurons within the spinal cord with lidocaine, or cutting communication between the spinal cord and the periphery (sciatic transection), eliminates the capacity to learn, which implies that it depends on spinal neurons. Here we show that these manipulations have no effect on the maintenance of the learned response, which implicates a peripheral process. EMG showed that learning augments the muscular response evoked by motoneuron output and that this effect survives a sciatic transection. Quantitative fluorescent imaging revealed that training brings about an increase in the area and intensity of ACh receptor labeling at the neuromuscular junction (NMJ). It is hypothesized that efferent motoneuron output, in conjunction with electrical stimulation of the tibialis anterior muscle, strengthens the connection at the NMJ in a Hebbian manner. Supporting this, paired stimulation of the efferent nerve and tibialis anterior generated an increase in flexion duration and augmented the evoked electrical response without input from the spinal cord. Evidence is presented that glutamatergic signaling contributes to plasticity at the NMJ. Labeling for vesicular glutamate transporter is evident at the motor endplate. Intramuscular application of an NMDAR antagonist blocked the acquisition/maintenance of the learned response and the strengthening of the evoked electrical response.SIGNIFICANCE STATEMENT The neuromuscular junction (NMJ) is designed to faithfully elicit a muscular contraction in response to neural input. From this perspective, encoding environmental relations (learning) and the maintenance of a behavioral modification over time (memory) are assumed to reflect only modifications upstream from the NMJ, within the CNS. The current results challenge this view. Rats were trained to maintain a hind leg in a flexed position to avoid noxious stimulation. As expected, treatments that inhibit activity within the CNS, or disrupt peripheral communication, prevented learning. These manipulations did not affect the maintenance of the acquired response. The results imply that a peripheral modification at the NMJ contributes to the maintenance of the learned response.
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Affiliation(s)
- Kevin C Hoy
- Case Comprehensive Cancer Center/Case Western Reserve School of Medicine, Cleveland, Ohio 44106
| | - Misty M Strain
- U.S. Army Institute of Surgical Research, JBSA Fort Sam Houston, Houston, Texas 78234
| | - Joel D Turtle
- Department of Psychological and Brain Sciences, Texas A&M University, College Station, Texas 77843
| | - Kuan H Lee
- Department of Psychological and Brain Sciences, Texas A&M University, College Station, Texas 77843
| | - J Russell Huie
- Department of Neuroscience, University of California San Francisco, San Francisco, California 94110
| | - John J Hartman
- Department of Psychological and Brain Sciences, Texas A&M University, College Station, Texas 77843
| | - Megan M Tarbet
- Department of Psychological and Brain Sciences, Texas A&M University, College Station, Texas 77843
| | - Mark L Harlow
- Department of Biology, Texas A&M University, College Station, Texas 77843
| | - David S K Magnuson
- Department of Neurological Surgery, University of Louisville, Louisville, Kentucky 40202
| | - James W Grau
- Department of Psychological and Brain Sciences, Texas A&M University, College Station, Texas 77843
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5
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Glutamate at the Vertebrate Neuromuscular Junction: From Modulation to Neurotransmission. Cells 2019; 8:cells8090996. [PMID: 31466388 PMCID: PMC6770210 DOI: 10.3390/cells8090996] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 08/21/2019] [Accepted: 08/27/2019] [Indexed: 12/23/2022] Open
Abstract
Although acetylcholine is the major neurotransmitter operating at the skeletal neuromuscular junction of many invertebrates and of vertebrates, glutamate participates in modulating cholinergic transmission and plastic changes in the last. Presynaptic terminals of neuromuscular junctions contain and release glutamate that contribute to the regulation of synaptic neurotransmission through its interaction with pre- and post-synaptic receptors activating downstream signaling pathways that tune synaptic efficacy and plasticity. During vertebrate development, the chemical nature of the neurotransmitter at the vertebrate neuromuscular junction can be experimentally shifted from acetylcholine to other mediators (including glutamate) through the modulation of calcium dynamics in motoneurons and, when the neurotransmitter changes, the muscle fiber expresses and assembles new receptors to match the nature of the new mediator. Finally, in adult rodents, by diverting descending spinal glutamatergic axons to a denervated muscle, a functional reinnervation can be achieved with the formation of new neuromuscular junctions that use glutamate as neurotransmitter and express ionotropic glutamate receptors and other markers of central glutamatergic synapses. Here, we summarize the past and recent experimental evidences in support of a role of glutamate as a mediator at the synapse between the motor nerve ending and the skeletal muscle fiber, focusing on the molecules and signaling pathways that are present and activated by glutamate at the vertebrate neuromuscular junction.
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6
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Mojard Kalkhoran S, Chow SHJ, Walia JS, Gershome C, Saraev N, Kim B, Poburko D. VNUT and VMAT2 segregate within sympathetic varicosities and localize near preferred Cav2 isoforms in the rat tail artery. Am J Physiol Heart Circ Physiol 2018; 316:H89-H105. [PMID: 30311774 DOI: 10.1152/ajpheart.00560.2018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
ATP and norepinephrine (NE) are coreleased from peripheral sympathetic nerve terminals. Whether they are stored in the same vesicles has been debated for decades. Preferential dependence of NE or ATP release on Ca2+ influx through specific voltage-gated Ca2+ channel (Cav2) isoforms suggests that NE and ATP are stored in separate vesicle pools, but simultaneous imaging of NE and ATP containing vesicles within single varicosities has not been reported. We conducted an immunohistochemical study of vesicular monoamine transporter 2 (VMAT2/SLC18A2) and vesicular nucleotide translocase (VNUT/SLC17A9) as markers of vesicles containing NE and ATP in sympathetic nerves of the rat tail artery. A large fraction of varicosities exhibited neighboring, rather than overlapping, VNUT and VMAT2 fluorescent puncta. VMAT2, but not VNUT, colocalized with synaptotagmin 1. Cav2.1, Cav2.2, and Cav2.3 are expressed in nerves in the tunica adventitia. VMAT2 preferentially localized adjacent to Cav2.2 and Cav2.3 rather than Cav2.1. VNUT preferentially localized adjacent to Cav2.3 > Cav2.2 >> Cav2.1. With the use of wire myography, inhibition of field-stimulated vasoconstriction with the Cav2.3 blocker SNX-482 (0.25 µM) mimicked the effects of the P2X inhibitor suramin (100 µM) rather than the α-adrenergic inhibitor phentolamine (10 µM). Variable sensitivity to SNX-482 and suramin between animals closely correlated with Cav2.3 staining. We concluded that a majority of ATP and NE stores localize to separate vesicle pools that use different synaptotagmin isoforms and that localize near different Cav2 isoforms to mediate vesicle release. Cav2.3 appears to play a previously unrecognized role in mediating ATP release in the rat tail artery. NEW & NOTEWORTHY Immunofluorescence imaging of vesicular nucleotide translocase and vesicular monoamine transporter 2 in rat tail arteries revealed that ATP and norepinephrine, classical cotransmitters, localize to well-segregated vesicle pools. Furthermore, vesicular nucleotide translocase and vesicular monoamine transporter 2 exhibit preferential localization with specific Cav2 isoforms. These novel observations address long-standing debates regarding the mechanism(s) of sympathetic neurotransmitter corelease.
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Affiliation(s)
- Somayeh Mojard Kalkhoran
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University , Burnaby, British Columbia , Canada.,Centre for Cell Biology, Development and Disease, Simon Fraser University , Burnaby, British Columbia , Canada
| | - Sarah Heather Jane Chow
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University , Burnaby, British Columbia , Canada
| | - Jagdeep Singh Walia
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University , Burnaby, British Columbia , Canada
| | - Cynthia Gershome
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University , Burnaby, British Columbia , Canada
| | - Nickolas Saraev
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University , Burnaby, British Columbia , Canada
| | - BaRun Kim
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University , Burnaby, British Columbia , Canada
| | - Damon Poburko
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University , Burnaby, British Columbia , Canada.,Centre for Cell Biology, Development and Disease, Simon Fraser University , Burnaby, British Columbia , Canada
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7
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Menéndez-Méndez A, Díaz-Hernández JI, Ortega F, Gualix J, Gómez-Villafuertes R, Miras-Portugal MT. Specific Temporal Distribution and Subcellular Localization of a Functional Vesicular Nucleotide Transporter (VNUT) in Cerebellar Granule Neurons. Front Pharmacol 2017; 8:951. [PMID: 29311945 PMCID: PMC5744399 DOI: 10.3389/fphar.2017.00951] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Accepted: 12/15/2017] [Indexed: 12/14/2022] Open
Abstract
Adenosine triphosphate (ATP) is an important extracellular neurotransmitter that participates in several critical processes like cell differentiation, neuroprotection or axon guidance. Prior to its exocytosis, ATP must be stored in secretory vesicles, a process that is mediated by the Vesicular Nucleotide Transporter (VNUT). This transporter has been identified as the product of the SLC17A9 gene and it is prominently expressed in discrete brain areas, including the cerebellum. The main population of cerebellar neurons, the glutamatergic granule neurons, depends on purinergic signaling to trigger neuroprotective responses. However, while nucleotide receptors like P2X7 and P2Y13 are known to be involved in neuroprotection, the mechanisms that regulate ATP release in relation to such events are less clearly understood. In this work, we demonstrate that cerebellar granule cells express a functional VNUT that is involved in the regulation of ATP exocytosis. Numerous vesicles loaded with this nucleotide can be detected in these granule cells and are staining by the fluorescent ATP-marker, quinacrine. High potassium stimulation reduces quinacrine fluorescence in granule cells, indicating they release ATP via calcium dependent exocytosis. Specific subcellular markers were used to assess the localization of VNUT in granule cells, and the transporter was detected in both the axonal and somatodendritic compartments, most predominantly in the latter. However, co-localization with the specific lysosomal marker LAMP-1 indicated that VNUT can also be found in non-synaptic vesicles, such as lysosomes. Interestingly, the weak co-localization between VNUT and VGLUT1 suggests that the ATP and glutamate vesicle pools are segregated, as also observed in the cerebellar cortex. During post-natal cerebellar development, VNUT is found in granule cell precursors, co-localizing with markers of immature cells like doublecortin, suggesting that this transporter may be implicated in the initial stages of granule cell development.
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Affiliation(s)
- Aida Menéndez-Méndez
- Department of Biochemistry and Molecular Biology, Faculty of Veterinary, Complutense University of Madrid, Madrid, Spain.,University Institute of Neurochemistry Research (IUIN), Complutense University of Madrid, Madrid, Spain.,Instituto de Investigación Sanitaria del Hospital Clínico San Carlos, Madrid, Spain
| | - Juan I Díaz-Hernández
- Department of Biochemistry and Molecular Biology, Faculty of Veterinary, Complutense University of Madrid, Madrid, Spain.,University Institute of Neurochemistry Research (IUIN), Complutense University of Madrid, Madrid, Spain.,Instituto de Investigación Sanitaria del Hospital Clínico San Carlos, Madrid, Spain
| | - Felipe Ortega
- Department of Biochemistry and Molecular Biology, Faculty of Veterinary, Complutense University of Madrid, Madrid, Spain.,University Institute of Neurochemistry Research (IUIN), Complutense University of Madrid, Madrid, Spain.,Instituto de Investigación Sanitaria del Hospital Clínico San Carlos, Madrid, Spain
| | - Javier Gualix
- Department of Biochemistry and Molecular Biology, Faculty of Veterinary, Complutense University of Madrid, Madrid, Spain.,University Institute of Neurochemistry Research (IUIN), Complutense University of Madrid, Madrid, Spain.,Instituto de Investigación Sanitaria del Hospital Clínico San Carlos, Madrid, Spain
| | - Rosa Gómez-Villafuertes
- Department of Biochemistry and Molecular Biology, Faculty of Veterinary, Complutense University of Madrid, Madrid, Spain.,University Institute of Neurochemistry Research (IUIN), Complutense University of Madrid, Madrid, Spain.,Instituto de Investigación Sanitaria del Hospital Clínico San Carlos, Madrid, Spain
| | - María T Miras-Portugal
- Department of Biochemistry and Molecular Biology, Faculty of Veterinary, Complutense University of Madrid, Madrid, Spain.,University Institute of Neurochemistry Research (IUIN), Complutense University of Madrid, Madrid, Spain.,Instituto de Investigación Sanitaria del Hospital Clínico San Carlos, Madrid, Spain
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8
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Lamotte d'Incamps B, Bhumbra GS, Foster JD, Beato M, Ascher P. Segregation of glutamatergic and cholinergic transmission at the mixed motoneuron Renshaw cell synapse. Sci Rep 2017. [PMID: 28642492 PMCID: PMC5481398 DOI: 10.1038/s41598-017-04266-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In neonatal mice motoneurons excite Renshaw cells by releasing both acetylcholine (ACh) and glutamate. These two neurotransmitters activate two types of nicotinic receptors (nAChRs) (the homomeric α7 receptors and the heteromeric α*ß* receptors) as well as the two types of glutamate receptors (GluRs) (AMPARs and NMDARs). Using paired recordings, we confirm that a single motoneuron can release both transmitters on a single post-synaptic Renshaw cell. We then show that co-transmission is preserved in adult animals. Kinetic analysis of miniature EPSCs revealed quantal release of mixed events associating AMPARs and NMDARs, as well as α7 and α*ß* nAChRs, but no evidence was found for mEPSCs associating nAChRs with GluRs. Bayesian Quantal Analysis (BQA) of evoked EPSCs showed that the number of functional contacts on a single Renshaw cell is more than halved when the nicotinic receptors are blocked, confirming that the two neurotransmitters systems are segregated. Our observations can be explained if ACh and glutamate are released from common vesicles onto spatially segregated post-synaptic receptors clusters, but a pre-synaptic segregation of cholinergic and glutamatergic release sites is also possible.
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Affiliation(s)
- Boris Lamotte d'Incamps
- Center for Neurophysics, Physiology and Pathologies, CNRS UMR 8119, Université Paris Descartes, Paris, France.
| | - Gardave S Bhumbra
- Department of Neuroscience, Physiology and Pharmacology, UCL, Gower Street, London, United Kingdom
| | - Joshua D Foster
- Department of Neuroscience, Physiology and Pharmacology, UCL, Gower Street, London, United Kingdom
| | - Marco Beato
- Department of Neuroscience, Physiology and Pharmacology, UCL, Gower Street, London, United Kingdom
| | - Philippe Ascher
- Physiologie cérébrale, CNRS UMR 8118, Université Paris Descartes, Paris, France
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9
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Vesicular nucleotide transporter (VNUT): appearance of an actress on the stage of purinergic signaling. Purinergic Signal 2017; 13:387-404. [PMID: 28616712 DOI: 10.1007/s11302-017-9568-1] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Accepted: 05/05/2017] [Indexed: 12/17/2022] Open
Abstract
Vesicular storage of ATP is one of the processes initiating purinergic chemical transmission. Although an active transport mechanism was postulated to be involved in the processes, a transporter(s) responsible for the vesicular storage of ATP remained unidentified for some time. In 2008, SLC17A9, the last identified member of the solute carrier 17 type I inorganic phosphate transporter family, was found to encode the vesicular nucleotide transporter (VNUT) that is responsible for the vesicular storage of ATP. VNUT transports various nucleotides in a membrane potential-dependent fashion and is expressed in the various ATP-secreting cells. Mice with knockout of the VNUT gene lose vesicular storage and release of ATP from neurons and neuroendocrine cells, resulting in blockage of the initiation of purinergic chemical transmission. Thus, VNUT plays an essential role in the vesicular storage and release of ATP. The VNUT knockout mice exhibit resistance for neuropathic pain and a therapeutic effect against diabetes by way of increased insulin sensitivity. Thus, VNUT inhibitors and suppression of VNUT gene expression may be used for therapeutic purposes through suppression of purinergic chemical transmission. This review summarizes the studies to date on VNUT and discusses what we have learned about the relevance of vesicular ATP release as a potential drug target.
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10
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Frahm S, Antolin-Fontes B, Görlich A, Zander JF, Ahnert-Hilger G, Ibañez-Tallon I. An essential role of acetylcholine-glutamate synergy at habenular synapses in nicotine dependence. eLife 2015; 4:e11396. [PMID: 26623516 PMCID: PMC4718731 DOI: 10.7554/elife.11396] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Accepted: 11/03/2015] [Indexed: 12/24/2022] Open
Abstract
A great deal of interest has been focused recently on the habenula and its critical role in aversion, negative-reward and drug dependence. Using a conditional mouse model of the ACh-synthesizing enzyme choline acetyltransferase (Chat), we report that local elimination of acetylcholine (ACh) in medial habenula (MHb) neurons alters glutamate corelease and presynaptic facilitation. Electron microscopy and immuno-isolation analyses revealed colocalization of ACh and glutamate vesicular transporters in synaptic vesicles (SVs) in the central IPN. Glutamate reuptake in SVs prepared from the IPN was increased by ACh, indicating vesicular synergy. Mice lacking CHAT in habenular neurons were insensitive to nicotine-conditioned reward and withdrawal. These data demonstrate that ACh controls the quantal size and release frequency of glutamate at habenular synapses, and suggest that the synergistic functions of ACh and glutamate may be generally important for modulation of cholinergic circuit function and behavior.
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Affiliation(s)
- Silke Frahm
- Molecular Neurobiology Group, Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Beatriz Antolin-Fontes
- Molecular Neurobiology Group, Max Delbrück Center for Molecular Medicine, Berlin, Germany
- Laboratory of Molecular Biology, The Rockefeller University, New York, United States
| | - Andreas Görlich
- Laboratory of Molecular Biology, The Rockefeller University, New York, United States
| | | | - Gudrun Ahnert-Hilger
- Institute for Integrative Neuroanatomy, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Ines Ibañez-Tallon
- Molecular Neurobiology Group, Max Delbrück Center for Molecular Medicine, Berlin, Germany
- Laboratory of Molecular Biology, The Rockefeller University, New York, United States
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11
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Synaptic vesicles contain small ribonucleic acids (sRNAs) including transfer RNA fragments (trfRNA) and microRNAs (miRNA). Sci Rep 2015; 5:14918. [PMID: 26446566 PMCID: PMC4597359 DOI: 10.1038/srep14918] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Accepted: 09/08/2015] [Indexed: 12/29/2022] Open
Abstract
Synaptic vesicles (SVs) are neuronal presynaptic organelles that load and release neurotransmitter at chemical synapses. In addition to classic neurotransmitters, we have found that synaptic vesicles isolated from the electric organ of Torpedo californica, a model cholinergic synapse, contain small ribonucleic acids (sRNAs), primarily the 5' ends of transfer RNAs (tRNAs) termed tRNA fragments (trfRNAs). To test the evolutionary conservation of SV sRNAs we examined isolated SVs from the mouse central nervous system (CNS). We found abundant levels of sRNAs in mouse SVs, including trfRNAs and micro RNAs (miRNAs) known to be involved in transcriptional and translational regulation. This discovery suggests that, in addition to inducing changes in local dendritic excitability through the release of neurotransmitters, SVs may, through the release of specific trfRNAs and miRNAs, directly regulate local protein synthesis. We believe these findings have broad implications for the study of chemical synaptic transmission.
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12
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Menéndez-Méndez A, Díaz-Hernández JI, Miras-Portugal MT. The vesicular nucleotide transporter (VNUT) is involved in the extracellular ATP effect on neuronal differentiation. Purinergic Signal 2015; 11:239-49. [PMID: 25847073 PMCID: PMC4425722 DOI: 10.1007/s11302-015-9449-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Accepted: 03/25/2015] [Indexed: 12/12/2022] Open
Abstract
Before being released, nucleotides are stored in secretory vesicles through the vesicular nucleotide transporter (VNUT). Once released, extracellular ATP participates in neuronal differentiation processes. Thus, the expression of a functional VNUT could be an additional component of the purinergic system which regulates neuronal differentiation and axonal elongation. In vitro expression of VNUT decreases neuritogenesis in N2a cells differentiated by retinoic acid treatment, whereas silencing of VNUT expression increases the number and length of neurites in these cells. These results highlight the role of VNUT in the neuritogenic process because this transporter regulates the ATP content in neurosecretory vesicles.
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Affiliation(s)
- Aida Menéndez-Méndez
- Facultad de Veterinaria, Departamento de Bioquímica y Biología Molecular IV, Universidad Complutense de Madrid, Madrid, Spain
| | - Juan Ignacio Díaz-Hernández
- Facultad de Veterinaria, Departamento de Bioquímica y Biología Molecular IV, Universidad Complutense de Madrid, Madrid, Spain
| | - M. Teresa Miras-Portugal
- Facultad de Veterinaria, Departamento de Bioquímica y Biología Molecular IV, Universidad Complutense de Madrid, Madrid, Spain
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