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Kim HY, Lee J, Kim HJ, Lee BE, Jeong J, Cho EJ, Jang HJ, Shin KJ, Kim MJ, Chae YC, Lee SE, Myung K, Baik JH, Suh PG, Kim JI. PLCγ1 in dopamine neurons critically regulates striatal dopamine release via VMAT2 and synapsin III. Exp Mol Med 2023; 55:2357-2375. [PMID: 37907739 PMCID: PMC10689754 DOI: 10.1038/s12276-023-01104-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Revised: 08/05/2023] [Accepted: 08/06/2023] [Indexed: 11/02/2023] Open
Abstract
Dopamine neurons are essential for voluntary movement, reward learning, and motivation, and their dysfunction is closely linked to various psychological and neurodegenerative diseases. Hence, understanding the detailed signaling mechanisms that functionally modulate dopamine neurons is crucial for the development of better therapeutic strategies against dopamine-related disorders. Phospholipase Cγ1 (PLCγ1) is a key enzyme in intracellular signaling that regulates diverse neuronal functions in the brain. It was proposed that PLCγ1 is implicated in the development of dopaminergic neurons, while the physiological function of PLCγ1 remains to be determined. In this study, we investigated the physiological role of PLCγ1, one of the key effector enzymes in intracellular signaling, in regulating dopaminergic function in vivo. We found that cell type-specific deletion of PLCγ1 does not adversely affect the development and cellular morphology of midbrain dopamine neurons but does facilitate dopamine release from dopaminergic axon terminals in the striatum. The enhancement of dopamine release was accompanied by increased colocalization of vesicular monoamine transporter 2 (VMAT2) at dopaminergic axon terminals. Notably, dopamine neuron-specific knockout of PLCγ1 also led to heightened expression and colocalization of synapsin III, which controls the trafficking of synaptic vesicles. Furthermore, the knockdown of VMAT2 and synapsin III in dopamine neurons resulted in a significant attenuation of dopamine release, while this attenuation was less severe in PLCγ1 cKO mice. Our findings suggest that PLCγ1 in dopamine neurons could critically modulate dopamine release at axon terminals by directly or indirectly interacting with synaptic machinery, including VMAT2 and synapsin III.
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Affiliation(s)
- Hye Yun Kim
- Department of Biological Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Jieun Lee
- Department of Biological Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Hyun-Jin Kim
- Department of Biological Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Byeong Eun Lee
- Department of Biological Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Jaewook Jeong
- Department of Biological Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Eun Jeong Cho
- Department of Biological Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Hyun-Jun Jang
- Herbal Medicine Resources Research Center, Korea Institute of Oriental Medicine, Naju, 58245, Republic of Korea
| | - Kyeong Jin Shin
- Department of Biological Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Min Ji Kim
- Department of Life Sciences, Korea University, Seoul, 02841, Korea
| | - Young Chan Chae
- Department of Biological Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Seung Eun Lee
- Research Animal Resource Center, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea
| | - Kyungjae Myung
- Center for Genomic Integrity, Institute for Basic Science (IBS), Ulsan, 44919, Republic of Korea
- Department of Biomedical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Ja-Hyun Baik
- Department of Life Sciences, Korea University, Seoul, 02841, Korea
| | - Pann-Ghill Suh
- Korea Brain Research Institute (KBRI), Daegu, 41062, Republic of Korea
| | - Jae-Ick Kim
- Department of Biological Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea.
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Huang SK, Lu CW, Lin TY, Wang SJ. Neuroprotective Role of the B Vitamins in the Modulation of the Central Glutamatergic Neurotransmission. CNS Neurol Disord Drug Targets 2022; 21:292-301. [PMID: 34477538 DOI: 10.2174/1871527320666210902165739] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 05/27/2021] [Accepted: 07/12/2021] [Indexed: 11/22/2022]
Abstract
BACKGROUND Regulation of glutamate release is crucial for maintaining normal brain function, but excess glutamate release is implicated in many neuropathological conditions. Therefore, the minimum glutamate release from presynaptic nerve terminals is an important neuroprotective mechanism. OBJECTIVE In this mini-review, we analyze the three B vitamins, namely vitamin B2 (riboflavin), vitamin B6 (pyridoxine), and vitamin B12 (cyanocobalamin), that affect the 4-aminopyridine (4- AP)-evoked glutamate release from presynaptic nerve terminal in rat and discuss their neuroprotective role. METHODS In this study, the measurements include glutamate release, DiSC3(5), and Fura-2. RESULTS The riboflavin, pyridoxine, and cyanocobalamin produced significant inhibitory effects on 4-aminopyridine-evoked glutamate release from rat cerebrocortical nerve terminals (synaptosomes) in a dose-dependent relationship. These presynaptic inhibitory actions of glutamate release are attributed to inhibition of physiologic Ca2+-dependent vesicular exocytosis but not Ca2+-independent nonvesicular release. These effects also did not affect membrane excitability, while diminished cytosolic (Ca2+)c through a reduction of direct Ca2+ influx via Cav2.2 (N-type) and Cav2.1 (P/Q-type) Ca2+ channels, rather than through indirect Ca2+induced Ca2+ release from ryanodine-sensitive intracellular stores. Furthermore, their effects were attenuated by GF109203X and Ro318220, two protein kinase C (PKC) inhibitors, suggesting suppression of PKC activity. Taken together, these results suggest that riboflavin, pyridoxine, and cyanocobalamin inhibit presynaptic vesicular glutamate release from rat cerebrocortical synaptosomes, through the depression Ca2+ influx via voltage- dependent Cav2.2 (N-type) and Cav2.1 (P/Q-type) Ca2+ channels, and PKC signaling cascade. CONCLUSION Therefore, these B vitamins may reduce the strength of glutamatergic synaptic transmission and is of considerable importance as potential targets for therapeutic agents in glutamate- induced excitation-related diseases.
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Affiliation(s)
- Shu-Kuei Huang
- Department of Anesthesiology, Far-Eastern Memorial Hospital, Pan-Chiao District, New Taipei City, Taiwan, China
| | - Cheng-Wei Lu
- Department of Anesthesiology, Far-Eastern Memorial Hospital, Pan-Chiao District, New Taipei City, Taiwan, China
| | - Tzu-Yu Lin
- Department of Anesthesiology, Far-Eastern Memorial Hospital, Pan-Chiao District, New Taipei City, Taiwan, China
| | - Su-Jane Wang
- Graduate Institute of Basic Medicine, Fu Jen Catholic University, No.510, Zhongzheng Rd., Xinzhuang Dist., New Taipei City, Taiwan, China
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Yapici-Eser H, Koroglu YE, Oztop-Cakmak O, Keskin O, Gursoy A, Gursoy-Ozdemir Y. Neuropsychiatric Symptoms of COVID-19 Explained by SARS-CoV-2 Proteins' Mimicry of Human Protein Interactions. Front Hum Neurosci 2021; 15:656313. [PMID: 33833673 PMCID: PMC8021734 DOI: 10.3389/fnhum.2021.656313] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Accepted: 02/23/2021] [Indexed: 12/16/2022] Open
Abstract
The first clinical symptoms focused on the presentation of coronavirus disease 2019 (COVID-19) have been respiratory failure, however, accumulating evidence also points to its presentation with neuropsychiatric symptoms, the exact mechanisms of which are not well known. By using a computational methodology, we aimed to explain the molecular paths of COVID-19 associated neuropsychiatric symptoms, based on the mimicry of the human protein interactions with SARS-CoV-2 proteins. Methods: Available 11 of the 29 SARS-CoV-2 proteins' structures have been extracted from Protein Data Bank. HMI-PRED (Host-Microbe Interaction PREDiction), a recently developed web server for structural PREDiction of protein-protein interactions (PPIs) between host and any microbial species, was used to find the "interface mimicry" through which the microbial proteins hijack host binding surfaces. Classification of the found interactions was conducted using the PANTHER Classification System. Results: Predicted Human-SARS-CoV-2 protein interactions have been extensively compared with the literature. Based on the analysis of the molecular functions, cellular localizations and pathways related to human proteins, SARS-CoV-2 proteins are found to possibly interact with human proteins linked to synaptic vesicle trafficking, endocytosis, axonal transport, neurotransmission, growth factors, mitochondrial and blood-brain barrier elements, in addition to its peripheral interactions with proteins linked to thrombosis, inflammation and metabolic control. Conclusion: SARS-CoV-2-human protein interactions may lead to the development of delirium, psychosis, seizures, encephalitis, stroke, sensory impairments, peripheral nerve diseases, and autoimmune disorders. Our findings are also supported by the previous in vivo and in vitro studies from other viruses. Further in vivo and in vitro studies using the proteins that are pointed here, could pave new targets both for avoiding and reversing neuropsychiatric presentations.
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Affiliation(s)
- Hale Yapici-Eser
- Department of Psychiatry, School of Medicine, Koç University, Istanbul, Turkey
- Research Center for Translational Medicine, Koç University, Istanbul, Turkey
| | - Yunus Emre Koroglu
- Research Center for Translational Medicine, Koç University, Istanbul, Turkey
- Graduate School of Sciences and Engineering, College of Engineering, Koç University, Istanbul, Turkey
| | - Ozgur Oztop-Cakmak
- Research Center for Translational Medicine, Koç University, Istanbul, Turkey
- Department of Neurology, School of Medicine, Koç University, Istanbul, Turkey
| | - Ozlem Keskin
- Research Center for Translational Medicine, Koç University, Istanbul, Turkey
- College of Engineering, Chemical and Biological Engineering, Koç University, Istanbul, Turkey
| | - Attila Gursoy
- Research Center for Translational Medicine, Koç University, Istanbul, Turkey
- Department of Computer Science and Engineering, College of Engineering, Koç University, Istanbul, Turkey
| | - Yasemin Gursoy-Ozdemir
- Research Center for Translational Medicine, Koç University, Istanbul, Turkey
- Department of Neurology, School of Medicine, Koç University, Istanbul, Turkey
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Silbern I, Pan KT, Fiosins M, Bonn S, Rizzoli SO, Fornasiero EF, Urlaub H, Jahn R. Protein Phosphorylation in Depolarized Synaptosomes: Dissecting Primary Effects of Calcium from Synaptic Vesicle Cycling. Mol Cell Proteomics 2021; 20:100061. [PMID: 33582301 PMCID: PMC7995663 DOI: 10.1016/j.mcpro.2021.100061] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Accepted: 02/02/2021] [Indexed: 01/20/2023] Open
Abstract
Synaptic transmission is mediated by the regulated exocytosis of synaptic vesicles. When the presynaptic membrane is depolarized by an incoming action potential, voltage-gated calcium channels open, resulting in the influx of calcium ions that triggers the fusion of synaptic vesicles (SVs) with the plasma membrane. SVs are recycled by endocytosis. Phosphorylation of synaptic proteins plays a major role in these processes, and several studies have shown that the synaptic phosphoproteome changes rapidly in response to depolarization. However, it is unclear which of these changes are directly linked to SV cycling and which might regulate other presynaptic functions that are also controlled by calcium-dependent kinases and phosphatases. To address this question, we analyzed changes in the phosphoproteome using rat synaptosomes in which exocytosis was blocked with botulinum neurotoxins (BoNTs) while depolarization-induced calcium influx remained unchanged. BoNT-treatment significantly alters the response of the synaptic phoshoproteome to depolarization and results in reduced phosphorylation levels when compared with stimulation of synaptosomes by depolarization with KCl alone. We dissect the primary Ca2+-dependent phosphorylation from SV-cycling-dependent phosphorylation and confirm an effect of such SV-cycling-dependent phosphorylation events on syntaxin-1a-T21/T23, synaptobrevin-S75, and cannabinoid receptor-1-S314/T322 on exo- and endocytosis in cultured hippocampal neurons.
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Affiliation(s)
- Ivan Silbern
- Institute of Clinical Chemistry, University Medical Center Goettingen, Goettingen, Germany; Bioanalytical Mass Spectrometry Group, Max Planck Institute for Biophysical Chemistry, Goettingen, Germany
| | - Kuan-Ting Pan
- Bioanalytical Mass Spectrometry Group, Max Planck Institute for Biophysical Chemistry, Goettingen, Germany
| | - Maksims Fiosins
- German Center for Neurodegenerative Diseases, Tübingen, Germany; Institute for Medical Systems Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Stefan Bonn
- German Center for Neurodegenerative Diseases, Tübingen, Germany; Institute for Medical Systems Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Silvio O Rizzoli
- Department of Neuro- and Sensory Physiology, University Medical Center Göttingen, Göttingen, Germany; Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Goettingen, Göttingen, Germany
| | - Eugenio F Fornasiero
- Department of Neuro- and Sensory Physiology, University Medical Center Göttingen, Göttingen, Germany.
| | - Henning Urlaub
- Institute of Clinical Chemistry, University Medical Center Goettingen, Goettingen, Germany; Bioanalytical Mass Spectrometry Group, Max Planck Institute for Biophysical Chemistry, Goettingen, Germany.
| | - Reinhard Jahn
- Laboratory of Neurobiology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany.
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Shan D, Guo S, Wu HK, Lv F, Jin L, Zhang M, Xie P, Wang Y, Song Y, Wu F, Lan F, Hu X, Cao CM, Zhang Y, Xiao RP. Cardiac Ischemic Preconditioning Promotes MG53 Secretion Through H 2O 2-Activated Protein Kinase C-δ Signaling. Circulation 2020; 142:1077-1091. [PMID: 32677469 DOI: 10.1161/circulationaha.119.044998] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
BACKGROUND Ischemic heart disease is the leading cause of morbidity and mortality worldwide. Ischemic preconditioning (IPC) is the most powerful intrinsic protection against cardiac ischemia/reperfusion injury. Previous studies have shown that a multifunctional TRIM family protein, MG53 (mitsugumin 53; also called TRIM72), not only plays an essential role in IPC-mediated cardioprotection against ischemia/reperfusion injury but also ameliorates mechanical damage. In addition to its intracellular actions, as a myokine/cardiokine, MG53 can be secreted from the heart and skeletal muscle in response to metabolic stress. However, it is unknown whether IPC-mediated cardioprotection is causally related to MG53 secretion and, if so, what the underlying mechanism is. METHODS Using proteomic analysis in conjunction with genetic and pharmacological approaches, we examined MG53 secretion in response to IPC and explored the underlying mechanism using rodents in in vivo, isolated perfused hearts, and cultured neonatal rat ventricular cardiomyocytes. Moreover, using recombinant MG53 proteins, we investigated the potential biological function of secreted MG53 in the context of IPC and ischemia/reperfusion injury. RESULTS We found that IPC triggered robust MG53 secretion in rodents in vivo, perfused hearts, and cultured cardiac myocytes without causing cell membrane leakage. Mechanistically, IPC promoted MG53 secretion through H2O2-evoked activation of protein kinase-C-δ. Specifically, IPC-induced myocardial MG53 secretion was mediated by H2O2-triggered phosphorylation of protein kinase-C-δ at Y311, which is necessary and sufficient to facilitate MG53 secretion. Functionally, systemic delivery of recombinant MG53 proteins to mimic elevated circulating MG53 not only restored IPC function in MG53-deficient mice but also protected rodent hearts from ischemia/reperfusion injury even in the absence of IPC. Moreover, oxidative stress by H2O2 augmented MG53 secretion, and MG53 knockdown exacerbated H2O2-induced cell injury in human embryonic stem cell-derived cardiomyocytes, despite relatively low basal expression of MG53 in human heart. CONCLUSIONS We conclude that IPC and oxidative stress can trigger MG53 secretion from the heart via an H2O2-protein kinase-C-δ-dependent mechanism and that extracellular MG53 can participate in IPC protection against cardiac ischemia/reperfusion injury.
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Affiliation(s)
- Dan Shan
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine (D.S., S.G., H.-K.W., F. Lv, L.J., M.Z., P.X., Y.W., Y.S., X.H., C.-M.C., Y.Z., R.-P.X.), Peking University, China
| | - Sile Guo
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine (D.S., S.G., H.-K.W., F. Lv, L.J., M.Z., P.X., Y.W., Y.S., X.H., C.-M.C., Y.Z., R.-P.X.), Peking University, China
| | - Hong-Kun Wu
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine (D.S., S.G., H.-K.W., F. Lv, L.J., M.Z., P.X., Y.W., Y.S., X.H., C.-M.C., Y.Z., R.-P.X.), Peking University, China
| | - Fengxiang Lv
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine (D.S., S.G., H.-K.W., F. Lv, L.J., M.Z., P.X., Y.W., Y.S., X.H., C.-M.C., Y.Z., R.-P.X.), Peking University, China
| | - Li Jin
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine (D.S., S.G., H.-K.W., F. Lv, L.J., M.Z., P.X., Y.W., Y.S., X.H., C.-M.C., Y.Z., R.-P.X.), Peking University, China
| | - Mao Zhang
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine (D.S., S.G., H.-K.W., F. Lv, L.J., M.Z., P.X., Y.W., Y.S., X.H., C.-M.C., Y.Z., R.-P.X.), Peking University, China
| | - Peng Xie
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine (D.S., S.G., H.-K.W., F. Lv, L.J., M.Z., P.X., Y.W., Y.S., X.H., C.-M.C., Y.Z., R.-P.X.), Peking University, China
| | - Yimei Wang
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine (D.S., S.G., H.-K.W., F. Lv, L.J., M.Z., P.X., Y.W., Y.S., X.H., C.-M.C., Y.Z., R.-P.X.), Peking University, China
| | - Ying Song
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine (D.S., S.G., H.-K.W., F. Lv, L.J., M.Z., P.X., Y.W., Y.S., X.H., C.-M.C., Y.Z., R.-P.X.), Peking University, China
| | - Fujian Wu
- Beijing Laboratory for Cardiovascular Precision Medicine, The Key Laboratory of Remodeling-Related Cardiovascular Disease, Ministry of Education, Beijing Collaborative Innovation Center for Cardiovascular Disorders, Anzhen Hospital, Capital Medical University, China (F.W., F. Lan).,Beijing Institute of Heart, Lung and Blood Vessel Diseases, China (F.W., F. Lan)
| | - Feng Lan
- Beijing Laboratory for Cardiovascular Precision Medicine, The Key Laboratory of Remodeling-Related Cardiovascular Disease, Ministry of Education, Beijing Collaborative Innovation Center for Cardiovascular Disorders, Anzhen Hospital, Capital Medical University, China (F.W., F. Lan).,Beijing Institute of Heart, Lung and Blood Vessel Diseases, China (F.W., F. Lan)
| | - Xinli Hu
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine (D.S., S.G., H.-K.W., F. Lv, L.J., M.Z., P.X., Y.W., Y.S., X.H., C.-M.C., Y.Z., R.-P.X.), Peking University, China
| | - Chun-Mei Cao
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine (D.S., S.G., H.-K.W., F. Lv, L.J., M.Z., P.X., Y.W., Y.S., X.H., C.-M.C., Y.Z., R.-P.X.), Peking University, China
| | - Yan Zhang
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine (D.S., S.G., H.-K.W., F. Lv, L.J., M.Z., P.X., Y.W., Y.S., X.H., C.-M.C., Y.Z., R.-P.X.), Peking University, China
| | - Rui-Ping Xiao
- State Key Laboratory of Membrane Biology, Institute of Molecular Medicine (D.S., S.G., H.-K.W., F. Lv, L.J., M.Z., P.X., Y.W., Y.S., X.H., C.-M.C., Y.Z., R.-P.X.), Peking University, China.,Beijing City Key Laboratory of Cardiometabolic Molecular Medicine (R.-P.X.), Peking University, China.,Peking-Tsinghua Center for Life Sciences, Beijing, China (R.-P.X.)
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Gruol DL, Hernandez RV, Roberts A. Alcohol Enhances Responses to High Frequency Stimulation in Hippocampus from Transgenic Mice with Increased Astrocyte Expression of IL-6. Cell Mol Neurobiol 2020; 41:1299-1310. [PMID: 32562098 DOI: 10.1007/s10571-020-00902-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Accepted: 06/09/2020] [Indexed: 12/29/2022]
Abstract
Recent studies show that alcohol exposure can induce glial production of neuroimmune factors in the CNS. Of these, IL-6 has gained attention because it is involved in a number of important physiological and pathophysiological processes that could be affected by alcohol-induced CNS production of IL-6, particularly under conditions of excessive alcohol use. For example, IL-6 has been shown to play a role in hippocampal behaviors and synaptic plasticity (long-term potentiation; LTP) associated with memory and learning. Surprisingly, in our in vitro studies of LTP at the Schaffer collateral to CA1 pyramidal neuron synapse in hippocampus from transgenic mice that express elevated levels of astrocyte produced IL-6 (TG), LTP was not altered by the increased levels of IL-6. However, exposure to acute alcohol revealed neuroadaptive changes that served to protect LTP against the alcohol-induced reduction of LTP observed in hippocampus from non-transgenic control mice (WT). Here we examined the induction phase of LTP to assess if presynaptic neuroadaptive changes occurred in the hippocampus of TG mice that contributed to the resistance of LTP to alcohol. Results are consistent with a role for IL-6-induced neuroadaptive effects on presynaptic mechanisms involved in transmitter release in the resistance of LTP to alcohol in hippocampus from the TG mice. These actions are important with respect to a role for IL-6 in physiological and pathophysiological processes in the CNS and in CNS actions of alcohol, especially when excessive alcohol used is comorbid with conditions associated with elevated levels of IL-6 in the CNS.
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Affiliation(s)
- Donna L Gruol
- Neuroscience Department, SR301, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA, 92037, USA.
| | - Ruben V Hernandez
- Neuroscience Department, SR301, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA, 92037, USA
| | - Amanda Roberts
- Animal Models Core Facility, The Scripps Research Institute, La Jolla, CA, 92037, USA
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7
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Maruoka H, Yamazoe R, Takahashi R, Yatsuo K, Ido D, Fuchigami Y, Hoshikawa F, Shimoke K. Molecular mechanism of nur77 gene expression and downstream target genes in the early stage of forskolin-induced differentiation in PC12 cells. Sci Rep 2020; 10:6325. [PMID: 32286359 PMCID: PMC7156746 DOI: 10.1038/s41598-020-62968-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Accepted: 03/23/2020] [Indexed: 11/20/2022] Open
Abstract
Forskolin promotes neuronal differentiation of PC12 cells via the PKA-CREB-dependent signaling pathway. Activation of PKA by forskolin phosphorylates CREB, which then binds to CRE sites in numerous gene promoters. However, it is unclear which gene contains the CRE sites responsible for forskolin-induced neuronal differentiation. In this study, we investigated how an immediate early gene, nur77, which has CRE sites in the promoter region, contributes to the early stage of differentiation of forskolin-treated PC12 cells. After treatment with forskolin, expression of Nur77 was upregulated within 1 hr. In addition, knockdown of nur77 inhibited neurite outgrowth induced by forskolin. We also revealed that the specific four CRE sites near the transcriptional start site (TSS) of nur77 were strongly associated with phosphorylated CREB within 1 hr after treatment with forskolin. To analyze the roles of these four sites, reporter assays using the nur77 promoter region were performed. The results showed that nur77 expression was mediated through three of the CRE sites, -242, -222, and -78, and that -78, the nearest of the three to the TSS of nur77, was particularly important. An analysis of neuronal markers controlled by Nur77 after A-CREB-Nur77-Synapsin1 signaling pathway plays a pivotal role in differentiation of forskolin-induced PC12 cells.
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Affiliation(s)
- Hiroki Maruoka
- Laboratory of Neurobiology, Department of Life Science and Biotechnology, Faculty of Chemistry, Materials and Bioengineering, Kansai University, 3-3-35, Yamate-cho, Suita, Osaka, 564-8680, Japan
| | - Ryosuke Yamazoe
- Laboratory of Neurobiology, Department of Life Science and Biotechnology, Faculty of Chemistry, Materials and Bioengineering, Kansai University, 3-3-35, Yamate-cho, Suita, Osaka, 564-8680, Japan
| | - Ryota Takahashi
- Laboratory of Neurobiology, Department of Life Science and Biotechnology, Faculty of Chemistry, Materials and Bioengineering, Kansai University, 3-3-35, Yamate-cho, Suita, Osaka, 564-8680, Japan
| | - Keisuke Yatsuo
- Laboratory of Neurobiology, Department of Life Science and Biotechnology, Faculty of Chemistry, Materials and Bioengineering, Kansai University, 3-3-35, Yamate-cho, Suita, Osaka, 564-8680, Japan
| | - Daiki Ido
- Laboratory of Neurobiology, Department of Life Science and Biotechnology, Faculty of Chemistry, Materials and Bioengineering, Kansai University, 3-3-35, Yamate-cho, Suita, Osaka, 564-8680, Japan
| | - Yuki Fuchigami
- Laboratory of Neurobiology, Department of Life Science and Biotechnology, Faculty of Chemistry, Materials and Bioengineering, Kansai University, 3-3-35, Yamate-cho, Suita, Osaka, 564-8680, Japan
| | - Fumiya Hoshikawa
- Laboratory of Neurobiology, Department of Life Science and Biotechnology, Faculty of Chemistry, Materials and Bioengineering, Kansai University, 3-3-35, Yamate-cho, Suita, Osaka, 564-8680, Japan
| | - Koji Shimoke
- Laboratory of Neurobiology, Department of Life Science and Biotechnology, Faculty of Chemistry, Materials and Bioengineering, Kansai University, 3-3-35, Yamate-cho, Suita, Osaka, 564-8680, Japan.
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Lee S, Eom T, Kim MK, Yang SG, Shim BS. Durable soft neural micro-electrode coating by an electrochemical synthesis of PEDOT:PSS / graphene oxide composites. Electrochim Acta 2019. [DOI: 10.1016/j.electacta.2019.04.099] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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Abstract
Until recently, glial cells have been considered mainly support cells for neurons in the mammalian brain. However, many studies have unveiled a variety of glial functions including electrolyte homeostasis, inflammation, synapse formation, metabolism, and the regulation of neurotransmission. The importance of these functions illuminates significant crosstalk between glial and neuronal cells. Importantly, it is known that astrocytes secrete signals that can modulate both presynaptic and postsynaptic function. It is also known that the lipid compositions of the pre- and post-synaptic membranes of neurons greatly impact functions such as vesicle fusion and receptor mobility. These data suggest an essential lipid-mediated communication between glial cells and neurons. Little is known, however, about how the lipid metabolism of both cell types may interact. In this review, we discuss neuronal and glial lipid metabolism and suggest how they might interact to impact neurotransmission.
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Affiliation(s)
- Casey N Barber
- Department of Biological Chemistry, The Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Daniel M Raben
- Department of Biological Chemistry, The Johns Hopkins University School of Medicine, Baltimore, MD, United States
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Dason JS, Allen AM, Vasquez OE, Sokolowski MB. Distinct functions of a cGMP-dependent protein kinase in nerve terminal growth and synaptic vesicle cycling. J Cell Sci 2019; 132:jcs.227165. [DOI: 10.1242/jcs.227165] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Accepted: 02/26/2019] [Indexed: 01/20/2023] Open
Abstract
Sustained neurotransmission requires the tight coupling of synaptic vesicle (SV) exocytosis and endocytosis. The mechanisms underlying this coupling are poorly understood. We tested the hypothesis that a cGMP-dependent protein kinase (PKG), encoded by the foraging (for) gene in Drosophila melanogaster, is critical for this process using a for null mutant, genomic rescues, and tissue specific rescues. We uncoupled FOR's exocytic and endocytic functions in neurotransmission using a temperature-sensitive shibire mutant in conjunction with fluorescein-assisted light inactivation of FOR. We discovered a dual role for presynaptic FOR, where FOR inhibits SV exocytosis during low frequency stimulation by negatively regulating presynaptic Ca2+ levels and maintains neurotransmission during high frequency stimulation by facilitating SV endocytosis. Additionally, glial FOR negatively regulated nerve terminal growth through TGF-β signaling and this developmental effect was independent from FOR's effects on neurotransmission. Overall, FOR plays a critical role in coupling SV exocytosis and endocytosis, thereby balancing these two components to maintain sustained neurotransmission.
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Affiliation(s)
- Jeffrey S. Dason
- Department of Cell & Systems Biology, University of Toronto, Toronto, Ontario, M5S 3B2, Canada
- Department of Biological Sciences, University of Windsor, Windsor, Ontario, N9B 3P4, Canada
| | - Aaron M. Allen
- Department of Cell & Systems Biology, University of Toronto, Toronto, Ontario, M5S 3B2, Canada
- Present Address: Centre for Neural Circuits and Behaviour, University of Oxford, OX1 3SR Oxford, UK
| | - Oscar E. Vasquez
- Department of Ecology & Evolutionary Biology, University of Toronto, Toronto, Ontario, M5S 3B2, Canada
| | - Marla B. Sokolowski
- Department of Cell & Systems Biology, University of Toronto, Toronto, Ontario, M5S 3B2, Canada
- Department of Ecology & Evolutionary Biology, University of Toronto, Toronto, Ontario, M5S 3B2, Canada
- Child and Brain Development Program, Canadian Institute for Advanced Research (CIFAR), Toronto, Ontario, M5G 1M1, Canada
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11
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Lanni C, Fagiani F, Racchi M, Preda S, Pascale A, Grilli M, Allegri N, Govoni S. Beta-amyloid short- and long-term synaptic entanglement. Pharmacol Res 2019; 139:243-260. [DOI: 10.1016/j.phrs.2018.11.018] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Revised: 11/06/2018] [Accepted: 11/09/2018] [Indexed: 12/17/2022]
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12
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Liu JJ, Sharma K, Zangrandi L, Chen C, Humphrey SJ, Chiu YT, Spetea M, Liu-Chen LY, Schwarzer C, Mann M. In vivo brain GPCR signaling elucidated by phosphoproteomics. Science 2018; 360:360/6395/eaao4927. [PMID: 29930108 DOI: 10.1126/science.aao4927] [Citation(s) in RCA: 83] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Accepted: 04/27/2018] [Indexed: 12/12/2022]
Abstract
A systems view of G protein-coupled receptor (GPCR) signaling in its native environment is central to the development of GPCR therapeutics with fewer side effects. Using the kappa opioid receptor (KOR) as a model, we employed high-throughput phosphoproteomics to investigate signaling induced by structurally diverse agonists in five mouse brain regions. Quantification of 50,000 different phosphosites provided a systems view of KOR in vivo signaling, revealing novel mechanisms of drug action. Thus, we discovered enrichment of the mechanistic target of rapamycin (mTOR) pathway by U-50,488H, an agonist causing aversion, which is a typical KOR-mediated side effect. Consequently, mTOR inhibition during KOR activation abolished aversion while preserving beneficial antinociceptive and anticonvulsant effects. Our results establish high-throughput phosphoproteomics as a general strategy to investigate GPCR in vivo signaling, enabling prediction and modulation of behavioral outcomes.
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Affiliation(s)
- Jeffrey J Liu
- Department of Proteomics and Signal Transduction, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Kirti Sharma
- Department of Proteomics and Signal Transduction, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Luca Zangrandi
- Department of Pharmacology, Medical University of Innsbruck, 6020 Innsbruck, Austria
| | - Chongguang Chen
- Center for Substance Abuse Research and Department of Pharmacology, Temple University Lewis Katz School of Medicine, Philadelphia, PA 19140, USA
| | - Sean J Humphrey
- Department of Proteomics and Signal Transduction, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Yi-Ting Chiu
- Center for Substance Abuse Research and Department of Pharmacology, Temple University Lewis Katz School of Medicine, Philadelphia, PA 19140, USA
| | - Mariana Spetea
- Department of Pharmaceutical Chemistry, Institute of Pharmacy and Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, 6020 Innsbruck, Austria
| | - Lee-Yuan Liu-Chen
- Center for Substance Abuse Research and Department of Pharmacology, Temple University Lewis Katz School of Medicine, Philadelphia, PA 19140, USA
| | - Christoph Schwarzer
- Department of Pharmacology, Medical University of Innsbruck, 6020 Innsbruck, Austria.
| | - Matthias Mann
- Department of Proteomics and Signal Transduction, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany. .,Novo Nordisk Foundation Center for Protein Research, Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
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13
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Abstract
Casein kinase 1α (CK1α) is a multifunctional protein belonging to the CK1 protein family that is conserved in eukaryotes from yeast to humans. It regulates signaling pathways related to membrane trafficking, cell cycle progression, chromosome segregation, apoptosis, autophagy, cell metabolism, and differentiation in development, circadian rhythm, and the immune response as well as neurodegeneration and cancer. Given its involvement in diverse cellular, physiological, and pathological processes, CK1α is a promising therapeutic target. In this review, we summarize what is known of the biological functions of CK1α, and provide an overview of existing challenges and potential opportunities for advancing theranostics.
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Affiliation(s)
- Shaojie Jiang
- Department of Radiology, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Zhejiang, 310016, Hangzhou, China
| | - Miaofeng Zhang
- Department of Orthopaedics, Second Affiliated Hospital, School of Medicine, Zhejiang University, Zhejiang, 310009, Hangzhou, China
| | - Jihong Sun
- Department of Radiology, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Zhejiang, 310016, Hangzhou, China
| | - Xiaoming Yang
- Department of Radiology, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Zhejiang, 310016, Hangzhou, China. .,Image-Guided Bio-Molecular Intervention Research, Department of Radiology, University of Washington School of Medicine, Seattle, WA, 98109, USA.
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14
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Wakita M, Shoudai K, Oyama Y, Akaike N. 4,5-Dichloro-2-octyl-4-isothiazolin-3-one (DCOIT) modifies synaptic transmission in hippocampal CA3 neurons of rats. Chemosphere 2017; 184:337-346. [PMID: 28605704 DOI: 10.1016/j.chemosphere.2017.05.158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Revised: 05/23/2017] [Accepted: 05/28/2017] [Indexed: 06/07/2023]
Abstract
4,5-Dichloro-2-octyl-4-isothiazolin-3-one (DCOIT) is an alternative to organotin antifoulants, such as tributyltin and triphenyltin. Since DCOIT is found in harbors, bays, and coastal areas worldwide, this chemical compound may have some impacts on ecosystems. To determine whether DCOIT possesses neurotoxic activity by modifying synaptic transmission, we examined the effects of DCOIT on synaptic transmission in a 'synaptic bouton' preparation of rat brain. DCOIT at concentrations of 0.03-1 μM increased the amplitudes of evoked synaptic currents mediated by GABA and glutamate, while it reduced the amplitudes of these currents at 3-10 μM. However, the currents elicited by exogenous applications of GABA and glutamate were not affected by DCOIT. DCOIT at 1-10 μM increased the frequency of spontaneous synaptic currents mediated by GABA. It also increased the frequency of glutamate-mediated spontaneous currents at0.3-10 μM. The frequencies of miniature synaptic currents mediated by GABA and glutamate, observed in the presence of tetrodotoxin under external Ca2+-free conditions, were increased by 10 μM DCOIT. With the repetitive applications of DCOIT, the frequency of miniature synaptic currents mediated by glutamate was not increased by the second and third applications of DCOIT. Voltage-dependent Ca2+ channels were not affected by DCOIT, but DCOIT slowed the inactivation of voltage-dependent Na+ channels. These results suggest that DCOIT increases Ca2+ release from intracellular Ca2+ stores, resulting in the facilitation of both action potential-dependent and spontaneous neurotransmission, possibly leading to neurotoxicity.
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Affiliation(s)
- Masahito Wakita
- Research Division for Clinical Pharmacology, Medical Corporation, Jyuryokai, Kumamoto Kinoh Hospital, Kumamoto, 860-8518, Japan; Research Division for Life Science, Kumamoto Health Science University, Kumamoto, 861-5598, Japan.
| | - Kiyomitsu Shoudai
- Research Division for Life Science, Kumamoto Health Science University, Kumamoto, 861-5598, Japan
| | - Yasuo Oyama
- Laboratory of Cellular Signaling, Faculty of Biosciences and Bioindustry, Tokushima University, Tokushima, 770-8513, Japan.
| | - Norio Akaike
- Research Division for Clinical Pharmacology, Medical Corporation, Jyuryokai, Kumamoto Kinoh Hospital, Kumamoto, 860-8518, Japan; Department of Molecular Medicine, Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, 862-0973, Japan.
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15
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Katayama N, Yamamori S, Fukaya M, Kobayashi S, Watanabe M, Takahashi M, Manabe T. SNAP-25 phosphorylation at Ser187 regulates synaptic facilitation and short-term plasticity in an age-dependent manner. Sci Rep 2017; 7:7996. [PMID: 28801590 DOI: 10.1038/s41598-017-08237-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Accepted: 07/10/2017] [Indexed: 11/18/2022] Open
Abstract
Neurotransmitter release is mediated by the SNARE complex, but the role of its phosphorylation has scarcely been elucidated. Although PKC activators are known to facilitate synaptic transmission, there has been a heated debate on whether PKC mediates facilitation of neurotransmitter release through phosphorylation. One of the SNARE proteins, SNAP-25, is phosphorylated at the residue serine-187 by PKC, but its physiological significance has been unclear. To examine these issues, we analyzed mutant mice lacking the phosphorylation of SNAP-25 serine-187 and found that they exhibited reduced release probability and enhanced presynaptic short-term plasticity, suggesting that not only the release process, but also the dynamics of synaptic vesicles was regulated by the phosphorylation. Furthermore, it has been known that the release probability changes with development, but the precise mechanism has been unclear, and we found that developmental changes in release probability of neurotransmitters were regulated by the phosphorylation. These results indicate that SNAP-25 phosphorylation developmentally facilitates neurotransmitter release but strongly inhibits presynaptic short-term plasticity via modification of the dynamics of synaptic vesicles in presynaptic terminals.
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16
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Trexler AJ, Taraska JW. Regulation of insulin exocytosis by calcium-dependent protein kinase C in beta cells. Cell Calcium 2017; 67:1-10. [PMID: 29029784 DOI: 10.1016/j.ceca.2017.07.008] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Revised: 07/25/2017] [Accepted: 07/27/2017] [Indexed: 12/27/2022]
Abstract
The control of insulin release from pancreatic beta cells helps ensure proper blood glucose level, which is critical for human health. Protein kinase C has been shown to be one key control mechanism for this process. After glucose stimulation, calcium influx into beta cells triggers exocytosis of insulin-containing dense-core granules and activates protein kinase C via calcium-dependent phospholipase C-mediated generation of diacylglycerol. Activated protein kinase C potentiates insulin release by enhancing the calcium sensitivity of exocytosis, likely by affecting two main pathways that could be linked: (1) the reorganization of the cortical actin network, and (2) the direct phosphorylation of critical exocytotic proteins such as munc18, SNAP25, and synaptotagmin. Here, we review what is currently known about the molecular mechanisms of protein kinase C action on each of these pathways and how these effects relate to the control of insulin release by exocytosis. We identify remaining challenges in the field and suggest how these challenges might be addressed to advance our understanding of the regulation of insulin release in health and disease.
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Affiliation(s)
- Adam J Trexler
- National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, United States
| | - Justin W Taraska
- National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, United States.
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17
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Horváth D, Tamás I, Sipos A, Darula Z, Bécsi B, Nagy D, Iván J, Erdődi F, Lontay B. Myosin phosphatase and RhoA-activated kinase modulate neurotransmitter release by regulating SNAP-25 of SNARE complex. PLoS One 2017; 12:e0177046. [PMID: 28486561 PMCID: PMC5423623 DOI: 10.1371/journal.pone.0177046] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Accepted: 04/23/2017] [Indexed: 11/19/2022] Open
Abstract
Reversible phosphorylation of neuronal proteins plays an important role in the regulation of neurotransmitter release. Myosin phosphatase holoenzyme (MP) consists of a protein phosphatase-1 (PP1) catalytic subunit (PP1c) and a regulatory subunit, termed myosin phosphatase targeting subunit (MYPT1). The primary function of MP is to regulate the phosphorylation level of contractile proteins; however, recent studies have shown that MP is localized to neurons, and is also involved in the mediation of neuronal processes. Our goal was to investigate the effect of RhoA-activated kinase (ROK) and MP on the phosphorylation of one potential neuronal substrate, the synaptosomal-associated protein of 25 kDa (SNAP-25). SNAP-25 is a member of the SNARE (soluble N-ethylmaleimide sensitive factor attachment protein receptor) complex, along with synaptobrevin and syntaxin, and the primary role of SNAP25 is to mediate vesicle fusion. We showed that MYPT1 interacts with SNAP-25, as revealed by immunoprecipitation and surface plasmon resonance based binding studies. Mass spectrometry analysis and in vitro phosphorylation/dephosphorylation assays demonstrated that ROK phosphorylates, while MP dephosphorylates, SNAP-25 at Thr138. Silencing MYPT1 in B50 neuroblastoma cells increased phosphorylation of SNAP-25 at Thr138. Inhibition of PP1 with tautomycetin increased, whereas inhibition of ROK by H1152, decreased the phosphorylation of SNAP-25 at Thr138 in B50 cells, in cortical synaptosomes, and in brain slices. In response to the transduction of the MP inhibitor, kinase-enhanced PP1 inhibitor (KEPI), into synaptosomes, an increase in phosphorylation of SNAP-25 and a decrease in the extent of neurotransmitter release were detected. The interaction between SNAP-25 and syntaxin increased with decreasing phosphorylation of SNAP-25 at Thr138, upon inhibition of ROK. Our data suggest that ROK/MP play a crucial role in vesicle trafficking, fusion, and neurotransmitter release by oppositely regulating the phosphorylation of SNAP-25 at Thr138.
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Affiliation(s)
- Dániel Horváth
- Department of Medical Chemistry, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - István Tamás
- Department of Medical Chemistry, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Adrienn Sipos
- Department of Medical Chemistry, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Zsuzsanna Darula
- Hungarian Academy of Sciences, Proteomics Research Group, Biological Research Centre, Szeged, Hungary
| | - Bálint Bécsi
- Department of Medical Chemistry, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
- MTA-DE Cell Biology and Signaling Research Group, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Dénes Nagy
- Department of Medical Chemistry, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Judit Iván
- Department of Medical Chemistry, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
- MTA-DE Cell Biology and Signaling Research Group, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Ferenc Erdődi
- Department of Medical Chemistry, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
- MTA-DE Cell Biology and Signaling Research Group, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Beáta Lontay
- Department of Medical Chemistry, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
- * E-mail:
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18
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Min A, Lee YA, Kim KA, El-Benna J, Shin MH. SNAP23-Dependent Surface Translocation of Leukotriene B4 (LTB4) Receptor 1 Is Essential for NOX2-Mediated Exocytotic Degranulation in Human Mast Cells Induced by Trichomonas vaginalis-Secreted LTB4. Infect Immun 2017; 85:e00526-16. [PMID: 27795355 DOI: 10.1128/IAI.00526-16] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2016] [Accepted: 10/16/2016] [Indexed: 11/20/2022] Open
Abstract
Trichomonas vaginalis is a sexually transmitted parasite that causes vaginitis in women and itself secretes lipid mediator leukotriene B4 (LTB4). Mast cells are important effector cells of tissue inflammation during infection with parasites. Membrane-bridging SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) complexes are critical for fusion during exocytosis. Although T. vaginalis-derived secretory products (TvSP) have been shown to induce exocytosis in mast cells, information regarding the signaling mechanisms between mast cell activation and TvSP is limited. In this study, we found that SNAP23-dependent surface trafficking of LTB4 receptor 1 (BLT1) is required for nicotinamide adenine dinucleotide phosphate oxidase 2 (NOX2)-mediated exocytotic degranulation of mast cells induced by TvSP. First, stimulation with TvSP induced exocytotic degranulation and reactive oxygen species (ROS) generation in HMC-1 cells. Next, TvSP-induced ROS generation and exocytosis were strongly inhibited by transfection of BLT1 small interfering RNA (siRNA). TvSP induced trafficking of BLT1 from the cytosol to the plasma membrane. We also found that knockdown of SNAP23 abrogated TvSP-induced ROS generation, exocytosis, and surface trafficking of BLT1 in HMC-1 cells. By coimmunoprecipitation, there was a physical interaction between BLT1 and SNAP23 in TvSP-stimulated HMC-1 cells. Taken together, our results suggest that SNAP23-dependent surface trafficking of BLT1 is essential for exocytosis in human mast cells induced by T. vaginalis-secreted LTB4 Our data collectively demonstrate a novel regulatory mechanism for SNAP23-dependent mast cell activation of T. vaginalis-secreted LTB4 involving surface trafficking of BLT1. These results can help to explain how the cross talk mechanism between parasite and host can govern deliberately tissue inflammatory responses.
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19
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Muram S, Rowe TM, Hirasawa M. Presynaptic G Protein-Coupled Receptors Differentially Modulate Spontaneous Glutamate Release in the Supraoptic Nucleus. J Neuroendocrinol 2016; 28. [PMID: 26466355 DOI: 10.1111/jne.12329] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Revised: 10/07/2015] [Accepted: 10/09/2015] [Indexed: 12/01/2022]
Abstract
Spontaneous glutamate release in the supraoptic nucleus is modulated by a number of inhibitory G protein coupled receptors (GPCR), including GABAB , adenosine A1 and group III metabotropic glutamate receptors (mGluR). It remains unclear whether they have distinct roles or are redundant mechanisms that protect from hyperexcitation. To address this question, we facilitated spontaneous glutamate release using nifedipine or forskolin, which act in a protein kinase A (PKA)-independent and -dependent manner, respectively, and tested the effects of inhibitory GPCR agonists. We found that a GABAB receptor (GABAB R) agonist specifically inhibited forskolin-induced miniature excitatory postsynaptic currents (mEPSC), in contrast to an adenosine A1 receptor (A1R) agonist, which specifically inhibited nifedipine-induced mEPSCs. This suggests that GABAB Rs and A1 Rs modulate independent mechanisms activated by forskolin and nifedipine, respectively. However, the inhibitory effects of GABAB R and A1 R agonists on basal mEPSCs occluded each other, suggesting that these receptors also have an overlapping role. Group III mGluRs appear to have a greater control over glutamate release because agonists to these receptors inhibited both nifedipine- and forskolin-induced mEPSCs. mEPSCs induced by norepinephrine had the same characteristics as those induced by forskolin [i.e. PKA-dependence and sensitivity to GABAB R and group III mGluR agonists, but not an A1 R agonist]. In summary, the present study highlights the differential effects of GABAB R, A1 R and mGluR agonists on glutamate release stimulated by different secretagogues, including the endogenous neuromodulator norepinephrine. These results suggest that the roles of these inhibitory GPCRs are not completely redundant, and also indicate the physiological implications of having different excitatory and inhibitory GPCRs on the same synapse.
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Affiliation(s)
- S Muram
- Division of Biomedical Sciences, Memorial University, St John's, Newfoundland, Canada
| | - T M Rowe
- Division of Biomedical Sciences, Memorial University, St John's, Newfoundland, Canada
| | - M Hirasawa
- Division of Biomedical Sciences, Memorial University, St John's, Newfoundland, Canada
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20
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Gulino R. Neuroplasticity and Repair in Rodent Neurotoxic Models of Spinal Motoneuron Disease. Neural Plast 2016; 2016:2769735. [PMID: 26862439 DOI: 10.1155/2016/2769735] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Revised: 07/12/2015] [Accepted: 08/19/2015] [Indexed: 12/14/2022] Open
Abstract
Retrogradely transported toxins are widely used to set up protocols for selective lesioning of the nervous system. These methods could be collectively named "molecular neurosurgery" because they are able to destroy specific types of neurons by using targeted neurotoxins. Lectins such as ricin, volkensin, or modeccin and neuropeptide- or antibody-conjugated saporin represent the most effective toxins used for neuronal lesioning. Some of these specific neurotoxins could be used to induce selective depletion of spinal motoneurons. In this review, we extensively describe two rodent models of motoneuron degeneration induced by volkensin or cholera toxin-B saporin. In particular, we focus on the possible experimental use of these models to mimic neurodegenerative diseases, to dissect the molecular mechanisms of neuroplastic changes underlying the spontaneous functional recovery after motoneuron death, and finally to test different strategies of neural repair. The potential clinical applications of these approaches are also discussed.
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21
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Yamamori S, Sugaya D, Iida Y, Kokubo H, Itakura M, Suzuki E, Kataoka M, Miyaoka H, Takahashi M. Stress-induced phosphorylation of SNAP-25. Neurosci Lett 2014; 561:182-7. [DOI: 10.1016/j.neulet.2013.12.044] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Revised: 11/25/2013] [Accepted: 12/20/2013] [Indexed: 11/15/2022]
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22
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Hung KL, Wang SJ, Wang YC, Chiang TR, Wang CC. Upregulation of presynaptic proteins and protein kinases associated with enhanced glutamate release from axonal terminals (synaptosomes) of the medial prefrontal cortex in rats with neuropathic pain. Pain 2014; 155:377-387. [DOI: 10.1016/j.pain.2013.10.026] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Revised: 10/04/2013] [Accepted: 10/29/2013] [Indexed: 11/25/2022]
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23
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Zhang J, Yang LM, Pan XD, Lin N, Chen XC. Increased vesicular γ-GABA transporter and decreased phosphorylation of synapsin I in the rostral preoptic area is associated with decreased gonadotrophin-releasing hormone and c-Fos coexpression in middle-aged female mice. J Neuroendocrinol 2013; 25:753-61. [PMID: 23679216 DOI: 10.1111/jne.12050] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/27/2012] [Revised: 03/23/2013] [Accepted: 05/12/2013] [Indexed: 12/01/2022]
Abstract
Hypothalamic glutamate (Glu) and γ-GABA neurotransmission are involved in the ovarian hormone-induced gonadotrophin-releasing hormone (GnRH)/luteinising hormone (LH) surge in rodents. Studies have shown that reduced Glu and increased γ-GABA in the rostral preoptic area (rPOA) of the hypothalamus, where most activated GnRH neurones are located, play a key role in decreasing the reproductive function of female rats. However, the mechanism underlying the altered balance of these neurotransmitters is poorly understood. In the present study, we observed a decline in the function of GnRH neurones in the rPOA at the time of the GnRH/LH surge in middle-aged intact female mice with regular oestrous cycles. In young mice, there is an increase of vesicular Glu transporter 2 on the pro-oestrus afternoon, which is not observed in middle-aged mice. By contrast, vesicular γ-GABA transporter levels in young mice decrease at the time of the LH surge, whereas they increase in middle-aged mice. Of note, we found that, in middle-aged mice at the time of the GnRH/LH surge, the phosphorylation of synapsin I at Ser603 and Ca(2+) /calmodulin-dependent kinase IIα was significantly lower than in young mice. These data suggest that, in middle-aged mice, higher levels of presynaptic stores of GABA, a lack of increase of Glu and a decreased ability of synaptic vesicle mobilisation could account for the imbalance of Glu and GABA in the rPOA, which decreases the activation of GnRH neurones.
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Affiliation(s)
- Jing Zhang
- Key Laboratory of Brain Aging and Neurodegenerative Disease, Fujian Institute of Geriatrics, The Affiliated Union Hospital of Fujian Medical University, Fuzhou, China
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24
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Tomatis VM, Papadopulos A, Malintan NT, Martin S, Wallis T, Gormal RS, Kendrick-Jones J, Buss F, Meunier FA. Myosin VI small insert isoform maintains exocytosis by tethering secretory granules to the cortical actin. ACTA ACUST UNITED AC 2013; 200:301-20. [PMID: 23382463 PMCID: PMC3563687 DOI: 10.1083/jcb.201204092] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Before undergoing neuroexocytosis, secretory granules (SGs) are mobilized and tethered to the cortical actin network by an unknown mechanism. Using an SG pull-down assay and mass spectrometry, we found that myosin VI was recruited to SGs in a Ca(2+)-dependent manner. Interfering with myosin VI function in PC12 cells reduced the density of SGs near the plasma membrane without affecting their biogenesis. Myosin VI knockdown selectively impaired a late phase of exocytosis, consistent with a replenishment defect. This exocytic defect was selectively rescued by expression of the myosin VI small insert (SI) isoform, which efficiently tethered SGs to the cortical actin network. These myosin VI SI-specific effects were prevented by deletion of a c-Src kinase phosphorylation DYD motif, identified in silico. Myosin VI SI thus recruits SGs to the cortical actin network, potentially via c-Src phosphorylation, thereby maintaining an active pool of SGs near the plasma membrane.
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Affiliation(s)
- Vanesa M Tomatis
- Queensland Brain Institute, The University of Queensland, Brisbane, Queensland 4072, Australia
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25
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Iida Y, Yamamori S, Itakura M, Miyaoka H, Takahashi M. Protein phosphatase 2A dephosphorylates SNAP-25 through two distinct mechanisms in mouse brain synaptosomes. Neurosci Res 2013; 75:184-9. [DOI: 10.1016/j.neures.2013.01.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2012] [Revised: 01/07/2013] [Accepted: 01/07/2013] [Indexed: 01/03/2023]
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Shutov LP, Kim MS, Houlihan PR, Medvedeva YV, Usachev YM. Mitochondria and plasma membrane Ca2+-ATPase control presynaptic Ca2+ clearance in capsaicin-sensitive rat sensory neurons. J Physiol 2013; 591:2443-62. [PMID: 23381900 DOI: 10.1113/jphysiol.2012.249219] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The central processes of primary nociceptors form synaptic connections with the second-order nociceptive neurons located in the dorsal horn of the spinal cord. These synapses gate the flow of nociceptive information from the periphery to the CNS, and plasticity at these synapses contributes to centrally mediated hyperalgesia and allodynia. Although exocytosis and synaptic plasticity are controlled by Ca(2+) at the release sites, the mechanisms underlying presynaptic Ca(2+) signalling at the nociceptive synapses are not well characterized. We examined the presynaptic mechanisms regulating Ca(2+) clearance following electrical stimulation in capsaicin-sensitive nociceptors using a dorsal root ganglion (DRG)/spinal cord neuron co-culture system. Cytosolic Ca(2+) concentration ([Ca(2+)]i) recovery following electrical stimulation was well approximated by a monoexponential function with a ∼2 s. Inhibition of sarco-endoplasmic reticulum Ca(2+)-ATPase did not affect presynaptic [Ca(2+)]i recovery, and blocking plasmalemmal Na(+)/Ca(2+) exchange produced only a small reduction in the rate of [Ca(2+)]i recovery (∼12%) that was independent of intracellular K(+). However, [Ca(2+)]i recovery in presynaptic boutons strongly depended on the plasma membrane Ca(2+)-ATPase (PMCA) and mitochondria that accounted for ∼47 and 40%, respectively, of presynaptic Ca(2+) clearance. Measurements using a mitochondria-targeted Ca(2+) indicator, mtPericam, demonstrated that presynaptic mitochondria accumulated Ca(2+) in response to electrical stimulation. Quantitative analysis revealed that the mitochondrial Ca(2+) uptake is highly sensitive to presynaptic [Ca(2+)]i elevations, and occurs at [Ca(2+)]i levels as low as ∼200-300 nm. Using RT-PCR, we detected expression of several putative mitochondrial Ca(2+) transporters in DRG, such as MCU, Letm1 and NCLX. Collectively, this work identifies PMCA and mitochondria as the major regulators of presynaptic Ca(2+) signalling at the first sensory synapse, and underlines the high sensitivity of the mitochondrial Ca(2+) uniporter in neurons to cytosolic Ca(2+).
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Affiliation(s)
- Leonid P Shutov
- Y. M. Usachev: Department of Pharmacology, University of Iowa Carver College of Medicine, 2-340F BSB, 51 Newton Road, Iowa City, IA 52242, USA
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Martin N, Bossenmeyer-Pourié C, Koziel V, Jazi R, Audonnet S, Vert P, Guéant JL, Daval JL, Pourié G. Non-injurious neonatal hypoxia confers resistance to brain senescence in aged male rats. PLoS One 2012; 7:e48828. [PMID: 23173039 PMCID: PMC3500249 DOI: 10.1371/journal.pone.0048828] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2012] [Accepted: 10/05/2012] [Indexed: 11/19/2022] Open
Abstract
Whereas brief acute or intermittent episodes of hypoxia have been shown to exert a protective role in the central nervous system and to stimulate neurogenesis, other studies suggest that early hypoxia may constitute a risk factor that influences the future development of mental disorders. We therefore investigated the effects of a neonatal “conditioning-like” hypoxia (100% N2, 5 min) on the brain and the cognitive outcomes of rats until 720 days of age (physiologic senescence). We confirmed that such a short hypoxia led to brain neurogenesis within the ensuing weeks, along with reduced apoptosis in the hippocampus involving activation of Erk1/2 and repression of p38 and death-associated protein (DAP) kinase. At 21 days of age, increased thicknesses and cell densities were recorded in various subregions, with strong synapsin activation. During aging, previous exposure to neonatal hypoxia was associated with enhanced memory retrieval scores specifically in males, better preservation of their brain integrity than controls, reduced age-related apoptosis, larger hippocampal cell layers, and higher expression of glutamatergic and GABAergic markers. These changes were accompanied with a marked expression of synapsin proteins, mainly of their phosphorylated active forms which constitute major players of synapse function and plasticity, and with increases of their key regulators, i.e. Erk1/2, the transcription factor EGR-1/Zif-268 and Src kinase. Moreover, the significantly higher interactions between PSD-95 scaffolding protein and NMDA receptors measured in the hippocampus of 720-day-old male animals strengthen the conclusion of increased synaptic functional activity and plasticity associated with neonatal hypoxia. Thus, early non-injurious hypoxia may trigger beneficial long term effects conferring higher resistance to senescence in aged male rats, with a better preservation of cognitive functions.
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Affiliation(s)
- Nicolas Martin
- Inserm U954, Vandoeuvre-lès-Nancy, France
- Université de Lorraine, Faculté de Médecine, Vandoeuvre-lès-Nancy, France
| | - Carine Bossenmeyer-Pourié
- Inserm U954, Vandoeuvre-lès-Nancy, France
- Université de Lorraine, Faculté de Médecine, Vandoeuvre-lès-Nancy, France
| | - Violette Koziel
- Inserm U954, Vandoeuvre-lès-Nancy, France
- Université de Lorraine, Faculté de Médecine, Vandoeuvre-lès-Nancy, France
| | - Rozat Jazi
- Inserm U954, Vandoeuvre-lès-Nancy, France
- Université de Lorraine, Faculté de Médecine, Vandoeuvre-lès-Nancy, France
| | - Sandra Audonnet
- Inserm U954, Vandoeuvre-lès-Nancy, France
- Université de Lorraine, Faculté de Médecine, Vandoeuvre-lès-Nancy, France
| | - Paul Vert
- Service de Médecine Néonatale, Maternité Régionale Universitaire, Nancy, France
| | - Jean-Louis Guéant
- Inserm U954, Vandoeuvre-lès-Nancy, France
- Université de Lorraine, Faculté de Médecine, Vandoeuvre-lès-Nancy, France
- IRCCS, Oasi Maria S.S., Institute for Research on Mental Retardation and Brain Aging, Troina (EN), Italy
| | - Jean-Luc Daval
- Inserm U954, Vandoeuvre-lès-Nancy, France
- Université de Lorraine, Faculté de Médecine, Vandoeuvre-lès-Nancy, France
| | - Grégory Pourié
- Inserm U954, Vandoeuvre-lès-Nancy, France
- Université de Lorraine, Faculté de Médecine, Vandoeuvre-lès-Nancy, France
- * E-mail:
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Abstract
PD (Parkinson's disease) is a common neurodegenerative disease clinically characterized by bradykinesia, rigidity and resting tremor. Recent studies have proposed that synaptic dysfunction, implicated in numerous studies of animal models of PD, might be a key factor in PD. The molecular defects that lead to PD progression might be hidden at the presynaptic neuron: in fact accumulating evidence has shown that the majority of the genes linked to PD play a critical role at the presynaptic site. In the present paper, we focus on the presynaptic function of LRRK2 (leucine-rich repeat kinase 2), a protein that mutated represents the main genetic cause of familial PD described to date. Neurotransmission relies on proper presynaptic vesicle trafficking; defects in this process, variation in dopamine flow and alteration of presynaptic plasticity have been reported in several animal models of LRRK2 mutations. Furthermore, impaired dopamine turnover has been described in presymptomatic LRRK2 PD patients. Thus, given the pathological events occurring at the synapses of PD patients, the presynaptic site may represent a promising target for early diagnostic therapeutic intervention.
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Affiliation(s)
- Elisa Belluzzi
- Department of Biology, University of Padova, Via Ugo Bassi 58/B, Padua, Italy
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Lontay B, Pál B, Serfőző Z, Kőszeghy Á, Szücs G, Rusznák Z, Erdődi F. Protein phosphatase-1M and Rho-kinase affect exocytosis from cortical synaptosomes and influence neurotransmission at a glutamatergic giant synapse of the rat auditory system. J Neurochem 2012; 123:84-99. [PMID: 22817114 DOI: 10.1111/j.1471-4159.2012.07882.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Protein phosphatase-1M (PP1M, myosin phosphatase) consists of a PP1 catalytic subunit (PP1c) and the myosin phosphatase target subunit-1 (MYPT1). RhoA-activated kinase (ROK) regulates PP1M via inhibitory phosphorylation of MYPT1. Using multidisciplinary approaches, we have studied the roles of PP1M and ROK in neurotransmission. Electron microscopy demonstrated the presence of MYPT1 and ROK in both pre- and post-synaptic terminals. Tautomycetin (TMC), a PP1-specific inhibitor, decreased the depolarization-induced exocytosis from cortical synaptosomes. trans-4-[(1R)-1-aminoethyl]-N-4-pyridinylcyclohexanecarboxamide dihydrochloride, a ROK-specific inhibitor, had the opposite effect. Mass spectrometry analysis identified several MYPT1-bound synaptosomal proteins, of which interactions of synapsin-I, syntaxin-1, calcineurin-A subunit, and Ca(2+) /calmodulin-dependent kinase II with MYPT1 were confirmed. In intact synaptosomes, TMC increased, whereas Y27632 decreased the phosphorylation levels of MYPT1(Thr696) , myosin-II light chain(Ser19) , synapsin-I(Ser9) , and syntaxin-1(Ser14) , indicating that PP1M and ROK influence their phosphorylation status. Confocal microscopy indicated that MYPT1 and ROK are present in the rat ventral cochlear nucleus both pre- and post-synaptically. Analysis of the neurotransmission in an auditory glutamatergic giant synapse demonstrated that PP1M and ROK affect neurotransmission via both pre- and post-synaptic mechanisms. Our data suggest that both PP1M and ROK influence synaptic transmission, but further studies are needed to give a full account of their mechanism of action.
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Affiliation(s)
- Beáta Lontay
- Department of Medical Chemistry and Cell Biology and Signaling Research Group of the Hungarian Academy of Sciences, Medical and Health Science Center, University of Debrecen, Debrecen, Hungary
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Abstract
In the human brain, ≈30% of the energy is spent on synaptic transmission. Disappearance of synaptic activity is the earliest consequence of cerebral ischemia. The changes of synaptic function are generally assumed to be reversible and persistent damage is associated with membrane failure and neuronal death. However, there is overwhelming experimental evidence of isolated, but persistent, synaptic failure resulting from mild or moderate cerebral ischemia. Early failure results from presynaptic damage with impaired transmitter release. Proposed mechanisms include dysfunction of adenosine triphosphate-dependent calcium channels and a disturbed docking of glutamate-containing vesicles resulting from impaired phosphorylation. We review energy distribution among neuronal functions, focusing on energy usage of synaptic transmission. We summarize the effect of ischemia on neurotransmission and the evidence of long-lasting synaptic failure as a cause of persistent symptoms in patients with cerebral ischemia. Finally, we discuss the implications of synaptic failure in the diagnosis of cerebral ischemia, including the limited sensitivity of diffusion-weighted MRI in those cases in which damage is presumably limited to the synapses.
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Affiliation(s)
- Jeannette Hofmeijer
- Department of Neurology, Rijnstate Hospital, Wagnerlaan 55, 6815 AD Arnhem, The Netherlands.
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Kataoka M, Yamamori S, Suzuki E, Watanabe S, Sato T, Miyaoka H, Azuma S, Ikegami S, Kuwahara R, Suzuki-Migishima R, Nakahara Y, Nihonmatsu I, Inokuchi K, Katoh-Fukui Y, Yokoyama M, Takahashi M. A single amino acid mutation in SNAP-25 induces anxiety-related behavior in mouse. PLoS One 2011; 6:e25158. [PMID: 21949876 PMCID: PMC3176821 DOI: 10.1371/journal.pone.0025158] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2011] [Accepted: 08/27/2011] [Indexed: 11/19/2022] Open
Abstract
Synaptosomal-associated protein of 25 kDa (SNAP-25) is a presynaptic protein essential for neurotransmitter release. Previously, we demonstrate that protein kinase C (PKC) phosphorylates Ser187 of SNAP-25, and enhances neurotransmitter release by recruiting secretory vesicles near to the plasma membrane. As PKC is abundant in the brain and SNAP-25 is essential for synaptic transmission, SNAP-25 phosphorylation is likely to play a crucial role in the central nervous system. We therefore generated a mutant mouse, substituting Ser187 of SNAP-25 with Ala using “knock-in” technology. The most striking effect of the mutation was observed in their behavior. The homozygous mutant mice froze readily in response to environmental change, and showed strong anxiety-related behavior in general activity and light and dark preference tests. In addition, the mutant mice sometimes exhibited spontaneously occurring convulsive seizures. Microdialysis measurements revealed that serotonin and dopamine release were markedly reduced in amygdala. These results clearly indicate that PKC-dependent SNAP-25 phosphorylation plays a critical role in the regulation of emotional behavior as well as the suppression of epileptic seizures, and the lack of enhancement of monoamine release is one of the possible mechanisms underlying these defects.
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Affiliation(s)
- Masakazu Kataoka
- Department of Environmental Science and Technology, Faculty of Engineering, Shinshu University, Nagano-shi, Nagano, Japan
| | - Saori Yamamori
- Kitasato University School of Medicine, Sagamihara-shi, Kanagawa, Japan
| | - Eiji Suzuki
- Department of Psychiatry, International University of Health and Welfare Atami Hospital, Atami-shi, Shizuoka, Japan
| | - Shigeru Watanabe
- Kitasato University School of Medicine, Sagamihara-shi, Kanagawa, Japan
| | - Taku Sato
- Kitasato University School of Medicine, Sagamihara-shi, Kanagawa, Japan
| | - Hitoshi Miyaoka
- Kitasato University School of Medicine, Sagamihara-shi, Kanagawa, Japan
| | - Sadahiro Azuma
- Kitasato University School of Medicine, Sagamihara-shi, Kanagawa, Japan
| | - Shiro Ikegami
- Mitsubishi Kagaku Institute of Life Sciences, Machida-shi, Tokyo, Japan
| | - Reiko Kuwahara
- Mitsubishi Kagaku Institute of Life Sciences, Machida-shi, Tokyo, Japan
| | | | - Yohko Nakahara
- Mitsubishi Kagaku Institute of Life Sciences, Machida-shi, Tokyo, Japan
| | - Itsuko Nihonmatsu
- Mitsubishi Kagaku Institute of Life Sciences, Machida-shi, Tokyo, Japan
| | - Kaoru Inokuchi
- Mitsubishi Kagaku Institute of Life Sciences, Machida-shi, Tokyo, Japan
| | - Yuko Katoh-Fukui
- Mitsubishi Kagaku Institute of Life Sciences, Machida-shi, Tokyo, Japan
| | - Minesuke Yokoyama
- Mitsubishi Kagaku Institute of Life Sciences, Machida-shi, Tokyo, Japan
| | - Masami Takahashi
- Kitasato University School of Medicine, Sagamihara-shi, Kanagawa, Japan
- * E-mail:
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Ding Q, Ying Z, Gómez-Pinilla F. Exercise influences hippocampal plasticity by modulating brain-derived neurotrophic factor processing. Neuroscience 2011; 192:773-80. [PMID: 21756980 DOI: 10.1016/j.neuroscience.2011.06.032] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2011] [Revised: 05/19/2011] [Accepted: 06/09/2011] [Indexed: 11/21/2022]
Abstract
Exercise has been shown to impact brain plasticity and function by involving the action of brain-derived neurotrophic factor (BDNF); however, mechanisms involved are poorly understood. Two types of BDNF coexist in the brain, the precursor (proBDNF) and its mature product (mBDNF), which preferentially bind specific receptors and exert distinct functions. It is crucial to understand how exercise affects crucial steps in the BDNF processing and signaling to evaluate therapeutic applications. We found that 7 days of voluntary exercise increased both pro and mature BDNF in the rat hippocampus. Exercise also increased the activity of tissue-type plasminogen activator (tPA), a serine proteinase shown to facilitate proBDNF cleavage into mBDNF. The blockade of tPA activity reduced the exercise effects on proBDNF and mBDNF. The tPA blocking also inhibited the activation of TrkB receptor, and the TrkB signaling downstream effectors phospho-ERK, phospho-Akt, and phospho-CaMKII. The blocking of tPA also counteracted the effects of exercise on the plasticity markers phospho-synapsin I and growth-associated protein 43 (GAP-43). These results indicate that the effects of exercise on hippocampal plasticity are dependent on BDNF processing and subsequent TrkB signaling, with important implications for neuronal function.
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Abstract
Astrocytes have the ability to modulate neuronal excitability and synaptic transmission by the release of gliotransmitters. The importance of ATP released downstream of the activation of Gq-coupled receptors has been well established, but the mechanisms by which this release is regulated are unclear. The current work reveals that the elevation of diacylglycerol (DAG) in astrocytes induces vesicular ATP release. Unexpectedly, DAG-induced ATP release was found to be independent of PKC activation, but dependent upon activation of a C1 domain-containing protein. Astrocytes express the C1 domain-containing protein Munc13-1, which has been implicated in neuronal transmitter release, and RNAi-targeted downregulation of Munc13-1 inhibits astrocytic ATP release. These studies demonstrate that elevations of DAG induce the exocytotic release of ATP in astrocytes, likely via a Munc13-1-dependent mechanism.
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Delom F, Fessart D. Role of Phosphorylation in the Control of Clathrin-Mediated Internalization of GPCR. Int J Cell Biol 2011; 2011:246954. [PMID: 21765832 DOI: 10.1155/2011/246954] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2011] [Accepted: 04/01/2011] [Indexed: 12/17/2022] Open
Abstract
The process by which G protein-coupled receptors (GPCRs) are internalized through the clathrin-coated vesicles involves interactions of multifunctional adaptor proteins. These interactions are tightly controlled by phosphorylation and dephosphorylation mechanisms resulting in the regulation of receptor endocytosis. However, the identities of the kinases involved in this process remained largely unknown until recently. This paper discusses advances in our knowledge of the important role played by protein phosphorylation in the regulation of the endocytic machinery and how phosphorylation controls the coated vesicle cycle.
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Wöllert T, Patel A, Lee YL, Provance DW, Vought VE, Cosgrove MS, Mercer JA, Langford GM. Myosin5a tail associates directly with Rab3A-containing compartments in neurons. J Biol Chem 2011; 286:14352-61. [PMID: 21349835 DOI: 10.1074/jbc.m110.187286] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Myosin-Va (Myo5a) is a motor protein associated with synaptic vesicles (SVs) but the mechanism by which it interacts has not yet been identified. A potential class of binding partners are Rab GTPases and Rab3A is known to associate with SVs and is involved in SV trafficking. We performed experiments to determine whether Rab3A interacts with Myo5a and whether it is required for transport of neuronal vesicles. In vitro motility assays performed with axoplasm from the squid giant axon showed a requirement for a Rab GTPase in Myo5a-dependent vesicle transport. Furthermore, mouse recombinant Myo5a tail revealed that it associated with Rab3A in rat brain synaptosomal preparations in vitro and the association was confirmed by immunofluorescence imaging of primary neurons isolated from the frontal cortex of mouse brains. Synaptosomal Rab3A was retained on recombinant GST-tagged Myo5a tail affinity columns in a GTP-dependent manner. Finally, the direct interaction of Myo5a and Rab3A was determined by sedimentation velocity analytical ultracentrifugation using recombinant mouse Myo5a tail and human Rab3A. When both proteins were incubated in the presence of 1 mm GTPγS, Myo5a tail and Rab3A formed a complex and a direct interaction was observed. Further analysis revealed that GTP-bound Rab3A interacts with both the monomeric and dimeric species of the Myo5a tail. However, the interaction between Myo5a tail and nucleotide-free Rab3A did not occur. Thus, our results show that Myo5a and Rab3A are direct binding partners and interact on SVs and that the Myo5a/Rab3A complex is involved in transport of neuronal vesicles.
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Affiliation(s)
- Torsten Wöllert
- Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire 03755, USA
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37
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Abstract
Upon activation through high affinity IgE receptors (FcεRI), mast cells (MCs) can release up to 100% of their content of preformed mediators stored in cytoplasmic secretory granules by compound exocytosis. This causes Type I immediate hypersensitivity reactions and, in the case of inappropriate activation by allergens, the symptoms of allergy. Recent work has uncovered a central role of SNARE (Soluble N-ethylmaleimide-Sensitive Factor (NSF) Attachment Protein (SNAP) Receptors) proteins in regulating the numerous membrane fusion events during exocytosis. This has defined a series of new molecular actors in MC exocytosis that participate in the regulation of membrane fusion and the connection of the fusion machinery with early signaling events. The purpose of this chapter is to describe these proteins and provide a brief overview on their mechanism of action.
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Abstract
Synaptic plasticity in the most general terms represents the flexibility of neurotransmission in response to neuronal activity. Synaptic plasticity is essential both for the moment-by-moment modulation of neural activity in response to dynamic environmental cues and for long-term learning and memory formation. These temporal characteristics are served by an array of pre- and post-synaptic mechanisms that are frequently modulated by ethanol exposure. This modulation likely makes significant contributions to both alcohol abuse and dependence. In this review, I discuss the modulation of both short-term and long-term synaptic plasticity in the context of specific ethanol-sensitive cellular substrates. A general discussion of the available preclinical, animal-model based neurophysiology literature provides a comparison between results from in vitro and in vivo studies. Finally, in the context of alcohol abuse and dependence, the review proposes potential behavioral contributions by ethanol modulation of plasticity.
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Revest JM, Kaouane N, Mondin M, Le Roux A, Rougé-Pont F, Vallée M, Barik J, Tronche F, Desmedt A, Piazza PV. The enhancement of stress-related memory by glucocorticoids depends on synapsin-Ia/Ib. Mol Psychiatry 2010; 15:1125, 1140-51. [PMID: 20368707 PMCID: PMC2990189 DOI: 10.1038/mp.2010.40] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The activation of glucocorticoid receptors (GR) by glucocorticoids increases stress-related memory through the activation of the MAPK signaling pathway and the downstream transcription factor Egr-1. Here, using converging in vitro and in vivo approaches, respectively, GR-expressing cell lines, culture of hippocampal neurons, and GR genetically modified mice (GR(NesCre)), we identified synapsin-Ia/Ib as one of the effectors of the glucocorticoid signaling cascade. Stress and glucocorticoid-induced activation of the GR modulate synapsin-Ia/Ib through two complementary mechanisms. First, glucocorticoids driving Egr-1 expression increase the expression of synapsin-Ia/Ib, and second, glucocorticoids driving MAPK activation increase its phosphorylation. Finally, we showed that blocking fucosylation of synapsin-Ia/Ib in the hippocampus inhibits its expression and prevents the glucocorticoid-mediated increase in stress-related memory. In conclusion, our data provide a complete molecular pathway (GR/Egr-1/MAPK/Syn-Ia/Ib) through which stress and glucocorticoids enhance the memory of stress-related events and highlight the function of synapsin-Ia/Ib as molecular effector of the behavioral effects of stress.
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Affiliation(s)
- J-M Revest
- INSERM U862, Neurocentre Magendie, Pathophysiology of Addiction group, Bordeaux, France.
| | - N Kaouane
- Université de Bordeaux, Bordeaux, France,CNRS UMR5228, Cognitive and Integrative Neurosciences, Talence, France
| | - M Mondin
- Université de Bordeaux, Bordeaux, France,CNRS UMR 5091, Cellular Physiology of the Synapse, Bordeaux, France
| | - A Le Roux
- INSERM U862, Neurocentre Magendie, Pathophysiology of Addiction group, Bordeaux, France,Université de Bordeaux, Bordeaux, France
| | - F Rougé-Pont
- INSERM U862, Neurocentre Magendie, Pathophysiology of Addiction group, Bordeaux, France,Université de Bordeaux, Bordeaux, France
| | - M Vallée
- INSERM U862, Neurocentre Magendie, Pathophysiology of Addiction group, Bordeaux, France,Université de Bordeaux, Bordeaux, France
| | - J Barik
- CNRS FRE2401, Molecular Genetics, Neurophysiology and Behavior, Institute of Biology, Paris, France
| | - F Tronche
- CNRS FRE2401, Molecular Genetics, Neurophysiology and Behavior, Institute of Biology, Paris, France
| | - A Desmedt
- Université de Bordeaux, Bordeaux, France,CNRS UMR5228, Cognitive and Integrative Neurosciences, Talence, France
| | - P V Piazza
- INSERM U862, Neurocentre Magendie, Pathophysiology of Addiction group, Bordeaux, France,Université de Bordeaux, Bordeaux, France,Department of Pathophysiology, Université de Bordeaux, INSERM U862, Bordeaux F33077, France. E-mail: or
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Yasuda K, Itakura M, Aoyagi K, Sugaya T, Nagata E, Ihara H, Takahashi M. PKC-dependent inhibition of CA2+-dependent exocytosis from astrocytes. Glia 2010; 59:143-51. [DOI: 10.1002/glia.21083] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2010] [Accepted: 09/01/2010] [Indexed: 01/14/2023]
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41
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Li C, Shi H, Chen Z, Ye H, Song N, Yin S. Protein kinase A and C signaling induces bilirubin potentiation of GABA/glycinergic synaptic transmission in rat ventral cochlear nucleus neurons. Brain Res 2010; 1348:30-41. [DOI: 10.1016/j.brainres.2010.06.022] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2010] [Revised: 06/07/2010] [Accepted: 06/09/2010] [Indexed: 11/24/2022]
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42
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Lin TY, Lu CW, Huang WJ, Wang SJ. Osthole or imperatorin-mediated facilitation of glutamate release is associated with a synaptic vesicle mobilization in rat hippocampal glutamatergic nerve endings. Synapse 2010; 64:390-6. [DOI: 10.1002/syn.20738] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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43
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De Marinis YZ, Zhang E, Amisten S, Taneera J, Renström E, Rorsman P, Eliasson L. Enhancement of glucagon secretion in mouse and human pancreatic alpha cells by protein kinase C (PKC) involves intracellular trafficking of PKCalpha and PKCdelta. Diabetologia 2010; 53:717-29. [PMID: 20020096 DOI: 10.1007/s00125-009-1635-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2009] [Accepted: 11/19/2009] [Indexed: 10/20/2022]
Abstract
AIMS/HYPOTHESIS Protein kinase C (PKC) regulates exocytosis in various secretory cells. Here we studied intracellular translocation of the PKC isoenzymes PKCalpha and PKCdelta, and investigated how activation of PKC influences glucagon secretion in mouse and human pancreatic alpha cells. METHODS Glucagon release from intact islets was measured in static incubations, and the amounts released were determined by RIA. Exocytosis was monitored as increases in membrane capacitance using the patch-clamp technique. The expression of genes encoding PKC isoforms was analysed by real-time PCR. Intracellular PKC distribution was assessed by confocal microscopy. RESULTS The PKC activator phorbol 12-myristate 13-acetate (PMA) stimulated glucagon secretion from mouse and human islets about fivefold (p < 0.01). This stimulation was abolished by the PKC inhibitor bisindolylmaleimide (BIM). Whereas PMA potentiated exocytosis more than threefold (p < 0.001), BIM inhibited alpha cell exocytosis by 60% (p < 0.05). In mouse islets, the PKC isoenzymes, PKCalpha and PKCbeta1, were highly abundant, while in human islets PKCeta, PKCepsilon and PKCzeta were the dominant variants. PMA stimulation of human alpha cells correlated with the translocation of PKCalpha and PKCdelta from the cytosol to the cell periphery. In the mouse alpha cells, PKCdelta was similarly affected by PMA, whereas PKCalpha was already present at the cell membrane in the absence of PMA. This association of PKCalpha in alpha cells was principally dependent on Ca(2+) influx through the L-type Ca(2+) channel. CONCLUSIONS/INTERPRETATION PKC activation augments glucagon secretion in mouse and human alpha cells. This effect involves translocation of PKCalpha and PKCdelta to the plasma membrane, culminating in increased Ca(2+)-dependent exocytosis. In addition, we demonstrated that PKCalpha translocation and exocytosis exhibit differential Ca(2+) channel dependence.
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Affiliation(s)
- Y Z De Marinis
- Lund University Diabetes Centre, Department of Clinical Sciences, Clinical Research Centre, Lund University, CRC 91-11, UMAS entrance 72, SE-20502 Malmö, Sweden.
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Ohtani-kaneko R, Iwafuchi M, Iwakura T, Muraoka D, Yokosuka M, Shiga T, Watanabe C. Effects of estrogen on synapsin I distribution in developing hypothalamic neurons. Neurosci Res 2010; 66:180-8. [DOI: 10.1016/j.neures.2009.10.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2009] [Revised: 09/28/2009] [Accepted: 10/28/2009] [Indexed: 01/08/2023]
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Wang L, Peng R, Hu X, Gao Y, Wang S, Zhao L, Dong J, Su Z, Xu X, Gao R, Lei C. Abnormality of synaptic vesicular associated proteins in cerebral cortex and hippocampus after microwave exposure. Synapse 2009; 63:1010-6. [PMID: 19603498 DOI: 10.1002/syn.20684] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Studies were performed to determine the effects of microwave on synaptic vesicles and the expression of synaptic vesicular associated proteins including synapsin I, VAMP-2, syntaxin, and synaptophysin. 25 Wistar rats were exposed to microwave which the average power density was 30 mW/cm(2), and whole body average specific absorption rate was 14.1 W/kg for 5 min. Synaptosome preparations in the cerebral cortex and hippocampus were obtained by isotonic Percoll/sucrose discontinuous gradients at 6 h, 1, 3, and 7 days after radiation. The expression of synaptic vesicular associated proteins was measured using Western blots and image analysis. The interaction between VAMP-2 and syntaxin was examined by coimmunoprecipitation analysis. Synapsin I in the cerebral cortex were decreased at 3 days (P < 0.01) after radiation and in the hippocampus increased at 1 day (P < 0.01), decreased at 3 days (P < 0.01), increased again at 7 days (P < 0.01) after exposure, compared with the sham-treated controls. Synaptophysin were increased in 1-7 days (P < 0.01) after exposure in the cerebral cortex and hippocampus. VAMP-2 were decreased at 1 and 3 days (P < 0.01) and syntaxin were decreased in 6 h to 3 days (P < 0.01) after radiation in the cerebral cortex and hippocampus. The interactions between VAMP-2 and syntaxin were decreased at 3-7 days (P < 0.01) after radiation in the cerebral cortex and hippocampus, compared with the sham-treated controls. These results suggest that 30 mW/cm(2) (SAR 14.1 W/kg) microwave radiation can result in the perturbation of the synaptic vesicles associated proteins: synapsin I, synaptophysin, VAMP-2, and syntaxin. The perturbation could induce the deposit of synaptic vesicle, which might be relative to the dysfunction of the synaptic transmission, even the cognition deficit.
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Affiliation(s)
- Lifeng Wang
- Beijing Institute of Radiation Medicine, 27 Taiping Road, Beijing 100850, People's Republic of China
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Nieratschker V, Schubert A, Jauch M, Bock N, Bucher D, Dippacher S, Krohne G, Asan E, Buchner S, Buchner E. Bruchpilot in ribbon-like axonal agglomerates, behavioral defects, and early death in SRPK79D kinase mutants of Drosophila. PLoS Genet 2009; 5:e1000700. [PMID: 19851455 PMCID: PMC2759580 DOI: 10.1371/journal.pgen.1000700] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2009] [Accepted: 09/23/2009] [Indexed: 12/18/2022] Open
Abstract
Defining the molecular structure and function of synapses is a central theme in brain research. In Drosophila the Bruchpilot (BRP) protein is associated with T-shaped ribbons ("T-bars") at presynaptic active zones (AZs). BRP is required for intact AZ structure and normal evoked neurotransmitter release. By screening for mutations that affect the tissue distribution of Bruchpilot, we have identified a P-transposon insertion in gene CG11489 (location 79D) which shows high homology to mammalian genes for SR protein kinases (SRPKs). SRPKs phosphorylate serine-arginine rich splicing factors (SR proteins). Since proteins expressed from CG11489 cDNAs phosphorylate a peptide from a human SR protein in vitro, we name CG11489 the Drosophila Srpk79D gene. We have characterized Srpk79D transcripts and generated a null mutant. Mutation of the Srpk79D gene causes conspicuous accumulations of BRP in larval and adult nerves. At the ultrastructural level, these correspond to extensive axonal agglomerates of electron-dense ribbons surrounded by clear vesicles. Basic synaptic structure and function at larval neuromuscular junctions appears normal, whereas life expectancy and locomotor behavior of adult mutants are significantly impaired. All phenotypes of the mutant can be largely or completely rescued by panneural expression of SRPK79D isoforms. Isoform-specific antibodies recognize panneurally overexpressed GFP-tagged SRPK79D-PC isoform co-localized with BRP at presynaptic active zones while the tagged -PB isoform is found in spots within neuronal perikarya. SRPK79D concentrations in wild type apparently are too low to be revealed by these antisera. We propose that the Drosophila Srpk79D gene characterized here may be expressed at low levels throughout the nervous system to prevent the assembly of BRP containing agglomerates in axons and maintain intact brain function. The discovery of an SR protein kinase required for normal BRP distribution calls for the identification of its substrate and the detailed analysis of SRPK function for the maintenance of nervous system integrity.
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Affiliation(s)
- Vanessa Nieratschker
- Department of Genetics and Neurobiology, Julius-Maximilians-University, Würzburg, Germany
| | - Alice Schubert
- Department of Genetics and Neurobiology, Julius-Maximilians-University, Würzburg, Germany
| | - Mandy Jauch
- Department of Genetics and Neurobiology, Julius-Maximilians-University, Würzburg, Germany
| | - Nicole Bock
- Department of Genetics and Neurobiology, Julius-Maximilians-University, Würzburg, Germany
| | - Daniel Bucher
- Department of Genetics and Neurobiology, Julius-Maximilians-University, Würzburg, Germany
| | - Sonja Dippacher
- Department of Genetics and Neurobiology, Julius-Maximilians-University, Würzburg, Germany
- Institute of Anatomy and Cell Biology, Julius-Maximilians-University, Würzburg, Germany
| | - Georg Krohne
- Department of Electron Microscopy, Julius-Maximilians-University, Würzburg, Germany
| | - Esther Asan
- Institute of Anatomy and Cell Biology, Julius-Maximilians-University, Würzburg, Germany
| | - Sigrid Buchner
- Department of Genetics and Neurobiology, Julius-Maximilians-University, Würzburg, Germany
| | - Erich Buchner
- Department of Genetics and Neurobiology, Julius-Maximilians-University, Würzburg, Germany
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Moreno-Delgado D, Gómez-Ramírez J, Torrent-Moreno A, González-Sepúlveda M, Blanco I, Ortiz J. Different role of cAMP dependent protein kinase and CaMKII in H3 receptor regulation of histamine synthesis and release. Neuroscience 2009; 164:1244-51. [PMID: 19735700 DOI: 10.1016/j.neuroscience.2009.08.068] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2009] [Revised: 07/28/2009] [Accepted: 08/12/2009] [Indexed: 11/29/2022]
Abstract
Histamine H(3) autoreceptors induce a negative feedback on histamine synthesis and release. While it is known that cAMP/cAMP dependent protein kinase (PKA) and Ca(2+)/CaMKII transduction pathways mediate H(3) effects on histamine synthesis, the pathways regulating neuronal histamine release are poorly known. Given the potential use of H(3) ligands in cognitive diseases, we have developed a technique for the determination of H(3) effects on histamine synthesis and release in brain cortical miniprisms. Potassium-induced depolarization effects were impaired by blockade of calcium entry through N and P/Q channels, as well as of CaMKII, but release was not affected by activators or inhibitors of the cAMP/PKA pathway (1-methyl-3-isobutylxanthine (IBMX), N6,2'-O-dibutyryladenosine 3',5'-cyclic monophosphate sodium salt (db-cAMP) or myristoyl PKA inhibitor peptide 14-22 (PKI(14-22)). In contrast, forskolin stimulated histamine release, although independently of PKA. Stimulation of histamine H(3) receptors with the agonist imetit markedly reduced the depolarization increase of histamine release, apparently through P/Q calcium channel inhibition. The H(3) antagonist/inverse agonist thioperamide modestly stimulated histamine release. Thioperamide effect on release was not modified by the PKA inhibitor PKI(14-22), but it was blocked by the CaMKII inhibitor KN-62. These results indicate that H(3) autoreceptors regulate neuronal histamine release (1) independently of the cAMP/PKA cascade, and (2) through modulation of calcium entry and CaMKII activation during depolarization.
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Affiliation(s)
- D Moreno-Delgado
- Universitat Autonoma de Barcelona, Neuroscience Institute and Department of Biochemistry and Molecular Biology, School of Medicine, 08193 Bellaterra, Spain.
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Zhong H, Sia GM, Sato TR, Gray NW, Mao T, Khuchua Z, Huganir RL, Svoboda K. Subcellular dynamics of type II PKA in neurons. Neuron 2009; 62:363-74. [PMID: 19447092 PMCID: PMC2702487 DOI: 10.1016/j.neuron.2009.03.013] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2008] [Revised: 11/12/2008] [Accepted: 03/18/2009] [Indexed: 02/05/2023]
Abstract
Protein kinase A (PKA) plays multiple roles in neurons. The localization and specificity of PKA are largely controlled by A-kinase anchoring proteins (AKAPs). However, the dynamics of PKA in neurons and the roles of specific AKAPs are poorly understood. We imaged the distribution of type II PKA in hippocampal and cortical layer 2/3 pyramidal neurons in vitro and in vivo. PKA was concentrated in dendritic shafts compared to the soma, axons, and dendritic spines. This spatial distribution was imposed by the microtubule-binding protein MAP2, indicating that MAP2 is the dominant AKAP in neurons. Following cAMP elevation, catalytic subunits dissociated from the MAP2-tethered regulatory subunits and rapidly became enriched in nearby spines. The spatial gradient of type II PKA between dendritic shafts and spines was critical for the regulation of synaptic strength and long-term potentiation. Therefore, the localization and activity-dependent translocation of type II PKA are important determinants of PKA function.
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Affiliation(s)
- Haining Zhong
- Howard Hughes Medical Institute Janelia Farm Research Campus, Ashburn, VA 20147, USA.
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Nojiri M, Loyet KM, Klenchin VA, Kabachinski G, Martin TFJ. CAPS activity in priming vesicle exocytosis requires CK2 phosphorylation. J Biol Chem 2009; 284:18707-14. [PMID: 19460754 DOI: 10.1074/jbc.m109.017483] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
CAPS (Ca(2+)-dependent activator protein for secretion) functions in priming Ca(2+)-dependent vesicle exocytosis, but the regulation of CAPS activity has not been characterized. Here we show that phosphorylation by protein kinase CK2 is required for CAPS activity. Dephosphorylation eliminated CAPS activity in reconstituting Ca(2+)-dependent vesicle exocytosis in permeable and intact PC12 cells. Ser-5, -6, and -7 and Ser-1281 were identified by mass spectrometry as the major phosphorylation sites in the 1289 residue protein. Ser-5, -6, and -7 but not Ser-1281 to Ala substitutions abolished CAPS activity. Protein kinase CK2 phosphorylated CAPS in vitro at these sites and restored the activity of dephosphorylated CAPS. CK2 is the likely in vivo CAPS protein kinase based on inhibition of phosphorylation by tetrabromo-2-benzotriazole in PC12 cells and by the identity of in vivo and in vitro phosphorylation sites. CAPS phosphorylation by CK2 was constitutive, but the elevation of Ca(2+) in synaptosomes increased CAPS Ser-5 and -6 dephosphorylation, which terminates CAPS activity. These results identify a functionally important N-terminal phosphorylation site that regulates CAPS activity in priming vesicle exocytosis.
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Affiliation(s)
- Mari Nojiri
- Department of Biochemistry, University of Wisconsin, Madison, Wisconsin 53706, USA
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Yang TT, Wang SJ. Facilitation of glutamate release from rat cerebrocortical glutamatergic nerve terminals (synaptosomes) by phosphatidylserine and phosphatidylcholine. Synapse 2009; 63:215-23. [PMID: 19072841 DOI: 10.1002/syn.20600] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Phosphatidylserine (PS) and phosphatidylcholine (PC) have been shown to enhance cognitive function. Considering that brain glutamatergic system is thought to participate in cognitive processing, our objective was to determine the effect of PS and PC on glutamate release from the nerve terminal (synaptosome) freshly isolated from rat cerebral cortex. Data showed that both PS and PC potently facilitate 4-aminopyridine (4-AP)-evoked Ca(2+)-dependent and Ca(2+)-independent glutamate release. Facilitation of glutamate release by PS or PC was associated with an increase of 4-AP-evoked depolarization and downstream elevation of cytoplasmic free calcium concentration ([Ca(2+)](c)). In addition, glutamate release elicited by direct Ca(2+)-entry with Ca(2+)-ionophore (ionomycin) was also facilitated by PS or PC. Furthermore, PS- or PC-mediated facilitation of 4-AP-evoked glutamate release was superseded or suppressed by protein kinase C (PKC) activator and inhibitor, respectively. Together, these results suggest that PS or PC effects a facilitation of glutamate exocytosis by increasing nerve terminal excitability and Ca(2+) influx into cerebrocortical nerve terminals through a signaling cascade involving PKC.
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Affiliation(s)
- Tsung-Tsair Yang
- School of Medicine, Fu Jen Catholic University, Hsin-Chuang, Taipei Hsien, Taiwan
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