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Sun SED, Levenstein D, Li B, Mandelberg N, Chenouard N, Suutari BS, Sanchez S, Tian G, Rinzel J, Buzsáki G, Tsien RW. Synaptic homeostasis transiently leverages Hebbian mechanisms for a multiphasic response to inactivity. Cell Rep 2024; 43:113839. [PMID: 38507409 DOI: 10.1016/j.celrep.2024.113839] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 12/19/2023] [Accepted: 02/05/2024] [Indexed: 03/22/2024] Open
Abstract
Homeostatic regulation of synapses is vital for nervous system function and key to understanding a range of neurological conditions. Synaptic homeostasis is proposed to operate over hours to counteract the destabilizing influence of long-term potentiation (LTP) and long-term depression (LTD). The prevailing view holds that synaptic scaling is a slow first-order process that regulates postsynaptic glutamate receptors and fundamentally differs from LTP or LTD. Surprisingly, we find that the dynamics of scaling induced by neuronal inactivity are not exponential or monotonic, and the mechanism requires calcineurin and CaMKII, molecules dominant in LTD and LTP. Our quantitative model of these enzymes reconstructs the unexpected dynamics of homeostatic scaling and reveals how synapses can efficiently safeguard future capacity for synaptic plasticity. This mechanism of synaptic adaptation supports a broader set of homeostatic changes, including action potential autoregulation, and invites further inquiry into how such a mechanism varies in health and disease.
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Affiliation(s)
- Simón E D Sun
- Center for Neural Science, New York University, New York, NY 10003, USA; Department of Neuroscience and Physiology, Neuroscience Institute, New York University Langone Health, New York, NY 10016, USA; Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
| | - Daniel Levenstein
- Center for Neural Science, New York University, New York, NY 10003, USA; Department of Neuroscience and Physiology, Neuroscience Institute, New York University Langone Health, New York, NY 10016, USA; Montreal Neurological Institute, Department of Neurology and Neurosurgery, McGill University, 3810 University Street, Montreal, QC, Canada
| | - Boxing Li
- Department of Neuroscience and Physiology, Neuroscience Institute, New York University Langone Health, New York, NY 10016, USA; Neuroscience Program, Guangdong Provincial Key Laboratory of Brain Function and Disease, Zhongshan School of Medicine and the Fifth Affiliated Hospital, Sun Yat-sen University, Guangzhou 510810, China
| | - Nataniel Mandelberg
- Department of Neuroscience and Physiology, Neuroscience Institute, New York University Langone Health, New York, NY 10016, USA
| | - Nicolas Chenouard
- Department of Neuroscience and Physiology, Neuroscience Institute, New York University Langone Health, New York, NY 10016, USA; Sorbonne Université, INSERM U1127, UMR CNRS 7225, Institut du Cerveau (ICM), 47 bld de l'hôpital, 75013 Paris, France
| | - Benjamin S Suutari
- Center for Neural Science, New York University, New York, NY 10003, USA; Department of Neuroscience and Physiology, Neuroscience Institute, New York University Langone Health, New York, NY 10016, USA
| | - Sandrine Sanchez
- Department of Neuroscience and Physiology, Neuroscience Institute, New York University Langone Health, New York, NY 10016, USA
| | - Guoling Tian
- Department of Neuroscience and Physiology, Neuroscience Institute, New York University Langone Health, New York, NY 10016, USA
| | - John Rinzel
- Center for Neural Science, New York University, New York, NY 10003, USA
| | - György Buzsáki
- Department of Neuroscience and Physiology, Neuroscience Institute, New York University Langone Health, New York, NY 10016, USA
| | - Richard W Tsien
- Center for Neural Science, New York University, New York, NY 10003, USA; Department of Neuroscience and Physiology, Neuroscience Institute, New York University Langone Health, New York, NY 10016, USA.
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Miyazawa D, Suzuki K, Sato H, Katsurayama N, Tahira T, Mizutani H, Ohara N. Docosahexaenoic acid contributes to increased CaMKII protein expression and a tendency to increase nNOS protein expression in differentiated NG108-15 cells. Drug Discov Ther 2023:2023.01003. [PMID: 37245984 DOI: 10.5582/ddt.2023.01003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Docosahexaenoic acid (DHA; 22:6n-3), an n-3 polyunsaturated fatty acid, has various important roles in brain functions. Nitric oxide (NO) produced by neuronal NO synthase (nNOS) and Ca2+/calmodulindependent protein kinase II (CaMKII) is also involved in brain functions. We investigated the influence of DHA on nNOS and CaMKII protein expression in differentiated NG108-15 cells. NG108-15 cells were seeded in 12-well plates, and after 24 h, the medium was replaced with Dulbecco's modified Eagle's medium containing 1% fetal bovine serum, 0.2 mM dibutyryl cyclic adenosine monophosphate and 100 nM dexamethasone as differentiation-inducing medium. When cells were cultured in differentiation-inducing medium, neurite-like outgrowths were observed on days 5 and 6. However, no significant difference in morphology was observed in cells with or without DHA treatment. With or without DHA addition, nNOS protein expression was increased on days 5 and 6 compared with day 0. This increase tended to be enhanced by DHA. CaMKII protein expression did not change after differentiation without DHA, but was significantly increased on day 6 compared with day 0 with DHA addition. These data indicate that DHA is involved in brain functions by regulating CaMKII and nNOS protein expression.
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Affiliation(s)
| | - Kinari Suzuki
- College of Pharmacy, Kinjo Gakuin University, Nagoya, Japan
| | - Hikari Sato
- College of Pharmacy, Kinjo Gakuin University, Nagoya, Japan
| | | | - Tomoko Tahira
- College of Pharmacy, Kinjo Gakuin University, Nagoya, Japan
| | | | - Naoki Ohara
- College of Pharmacy, Kinjo Gakuin University, Nagoya, Japan
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3
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Sun Z, Meng P, Su C, Ji S, Gao Y, Wang H, Tian J, Li C. PCC-0105002, a novel small molecule inhibitor of PSD95-nNOS protein-protein interactions, attenuates neuropathic pain and corrects motor disorder associated with neuropathic pain model. Toxicol Appl Pharmacol 2021; 429:115698. [PMID: 34428447 DOI: 10.1016/j.taap.2021.115698] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Revised: 08/16/2021] [Accepted: 08/18/2021] [Indexed: 01/11/2023]
Abstract
In view of postsynaptic density 95kDA (PSD95) tethers neuronal NO synthase (nNOS) to N-methyl-d-aspartate receptor (NMDAR), the PSD95-nNOS complex represents a therapeutic target of neuropathic pain. This study therefore sought to explore the ability of PCC-0105002, a novel PSD95-nNOS small molecule inhibitor, to alter pain sensitivity in rodent neuropathic pain models. Firstly, the IC50 of PCC-0105002 for PSD95 and NOS1 binding activity was determined using an Alpha Screen assay kit. Then, we examined the effects of PCC-0105002 in the mouse formalin test and in the rat spinal nerve ligation (SNL) model, and explored the ability of PCC-0105002 to mediate analgesia and to effect motor coordination in a rota-rod test. Moreover, the mechanisms whereby PCC-0105002 mediates analgesia was explored via western blotting, Golgi staining, and co-immunoprecipitation experiments in dorsal horn. The outcomes indicated that PCC-0105002 exhibited dose-dependent attenuation of phase II pain-associated behaviors in the formalin test. The result indicated that PCC-0105002 disrupted the PSD95-nNOS interaction with IC50 of 1.408 μM. In the SNL model, PCC-0105002 suppressed mechanical allodynia, thermal hyperalgesia, and abnormal dorsal horn wide dynamic range neuron discharge. PCC-0105002 mediated an analgesic effect comparable to that of MK-801, while it was better able to enhance motor coordination as compared with MK-801. Moreover, PCC-0105002 altered signaling downstream of NMDAR and thus functionally and structurally attenuating synaptic plasticity through respective regulation of the NR2B/GluR1/CaMKIIα and Rac1/RhoA pathways. These findings suggest that the novel PSD95-nNOS inhibitor PCC-0105002 is an effective agent for alleviating neuropathic pain, and that it produces fewer motor coordination-associated side effects than do NMDAR antagonists.
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Affiliation(s)
- Zhihong Sun
- School of Pharmacy, Key Laboratory of Molecular Pharmacology and Drug Evaluation (Yantai University), Ministry of Education, Collaborative Innovation Center of Advanced Drug Delivery System and Biotech Drugs in Universities of Shandong, Yantai University, Yantai, China
| | - Ping Meng
- School of Pharmacy, Key Laboratory of Molecular Pharmacology and Drug Evaluation (Yantai University), Ministry of Education, Collaborative Innovation Center of Advanced Drug Delivery System and Biotech Drugs in Universities of Shandong, Yantai University, Yantai, China
| | - Chunyu Su
- School of Pharmacy, Key Laboratory of Molecular Pharmacology and Drug Evaluation (Yantai University), Ministry of Education, Collaborative Innovation Center of Advanced Drug Delivery System and Biotech Drugs in Universities of Shandong, Yantai University, Yantai, China
| | - Shengmin Ji
- School of Pharmacy, Key Laboratory of Molecular Pharmacology and Drug Evaluation (Yantai University), Ministry of Education, Collaborative Innovation Center of Advanced Drug Delivery System and Biotech Drugs in Universities of Shandong, Yantai University, Yantai, China
| | - Yonglin Gao
- School of Life Science, Yantai University, Yantai 264005, China
| | - Hongbo Wang
- School of Pharmacy, Key Laboratory of Molecular Pharmacology and Drug Evaluation (Yantai University), Ministry of Education, Collaborative Innovation Center of Advanced Drug Delivery System and Biotech Drugs in Universities of Shandong, Yantai University, Yantai, China
| | - Jingwei Tian
- School of Pharmacy, Key Laboratory of Molecular Pharmacology and Drug Evaluation (Yantai University), Ministry of Education, Collaborative Innovation Center of Advanced Drug Delivery System and Biotech Drugs in Universities of Shandong, Yantai University, Yantai, China.
| | - Chunmei Li
- School of Pharmacy, Key Laboratory of Molecular Pharmacology and Drug Evaluation (Yantai University), Ministry of Education, Collaborative Innovation Center of Advanced Drug Delivery System and Biotech Drugs in Universities of Shandong, Yantai University, Yantai, China.
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Serine/Threonine Phosphatases in LTP: Two B or Not to Be the Protein Synthesis Blocker-Induced Impairment of Early Phase. Int J Mol Sci 2021; 22:ijms22094857. [PMID: 34064311 PMCID: PMC8125358 DOI: 10.3390/ijms22094857] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 04/27/2021] [Accepted: 04/30/2021] [Indexed: 11/25/2022] Open
Abstract
Dephosphorylation of target proteins at serine/threonine residues is one of the most crucial mechanisms regulating their activity and, consequently, the cellular functions. The role of phosphatases in synaptic plasticity, especially in long-term depression or depotentiation, has been reported. We studied serine/threonine phosphatase activity during the protein synthesis blocker (PSB)-induced impairment of long-term potentiation (LTP). Established protein phosphatase 2B (PP2B, calcineurin) inhibitor cyclosporin A prevented the LTP early phase (E-LTP) decline produced by pretreatment of hippocampal slices with cycloheximide or anisomycin. For the first time, we directly measured serine/threonine phosphatase activity during E-LTP, and its significant increase in PSB-treated slices was demonstrated. Nitric oxide (NO) donor SNAP also heightened phosphatase activity in the same manner as PSB, and simultaneous application of anisomycin + SNAP had no synergistic effect. Direct measurement of the NO production in hippocampal slices by the NO-specific fluorescent probe DAF-FM revealed that PSBs strongly stimulate the NO concentration in all studied brain areas: CA1, CA3, and dentate gyrus (DG). Cyclosporin A fully abolished the PSB-induced NO production in the hippocampus, suggesting a close relationship between nNOS and PP2B activity. Surprisingly, cyclosporin A alone impaired short-term plasticity in CA1 by decreasing paired-pulse facilitation, which suggests bi-directionality of the influences of PP2B in the hippocampus. In conclusion, we proposed a minimal model of signaling events that occur during LTP induction in normal conditions and the PSB-treated slices.
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Oxidative Stress Orchestrates MAPK and Nitric-Oxide Synthase Signal. Int J Mol Sci 2020; 21:ijms21228750. [PMID: 33228180 PMCID: PMC7699490 DOI: 10.3390/ijms21228750] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 11/17/2020] [Accepted: 11/17/2020] [Indexed: 12/15/2022] Open
Abstract
Reactive oxygen species (ROS) are not only harmful to cell survival but also essential to cell signaling through cysteine-based redox switches. In fact, ROS triggers the potential activation of mitogen-activated protein kinases (MAPKs). The 90 kDa ribosomal S6 kinase 1 (RSK1), one of the downstream mediators of the MAPK pathway, is implicated in various cellular processes through phosphorylating different substrates. As such, RSK1 associates with and phosphorylates neuronal nitric oxide (NO) synthase (nNOS) at Ser847, leading to a decrease in NO generation. In addition, the RSK1 activity is sensitive to inhibition by reversible cysteine-based redox modification of its Cys223 during oxidative stress. Aside from oxidative stress, nitrosative stress also contributes to cysteine-based redox modification. Thus, the protein kinases such as Ca2+/calmodulin (CaM)-dependent protein kinase I (CaMKI) and II (CaMKII) that phosphorylate nNOS could be potentially regulated by cysteine-based redox modification. In this review, we focus on the role of post-translational modifications in regulating nNOS and nNOS-phosphorylating protein kinases and communication among themselves.
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Araki S, Osuka K, Takata T, Tsuchiya Y, Watanabe Y. Coordination between Calcium/Calmodulin-Dependent Protein Kinase II and Neuronal Nitric Oxide Synthase in Neurons. Int J Mol Sci 2020; 21:ijms21217997. [PMID: 33121174 PMCID: PMC7662388 DOI: 10.3390/ijms21217997] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 10/21/2020] [Accepted: 10/22/2020] [Indexed: 12/15/2022] Open
Abstract
Ca2+/calmodulin (CaM)-dependent protein kinase II (CaMKII) is highly abundant in the brain and exhibits broad substrate specificity, thereby it is thought to participate in the regulation of neuronal death and survival. Nitric oxide (NO), produced by neuronal NO synthase (nNOS), is an important neurotransmitter and plays a role in neuronal activity including learning and memory processes. However, high levels of NO can contribute to excitotoxicity following a stroke and neurodegenerative disease. Aside from NO, nNOS also generates superoxide which is involved in both cell injury and signaling. CaMKII is known to activate and translocate from the cytoplasm to the post-synaptic density in response to neuronal activation where nNOS is predominantly located. Phosphorylation of nNOS at Ser847 by CaMKII decreases NO generation and increases superoxide generation. Conversely, NO-induced S-nitrosylation of CaMKII at Cys6 is a prominent determinant of the CaMKII inhibition in ATP competitive fashion. Thus, the "cross-talk" between CaMKII and NO/superoxide may represent important signal transduction pathways in brain. In this review, we introduce the molecular mechanism of and pathophysiological role of mutual regulation between CaMKII and nNOS in neurons.
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Affiliation(s)
- Shoma Araki
- Department of Pharmacology, Showa Pharmaceutical University, Machida, Tokyo 194-8543, Japan; (S.A.); (T.T.); (Y.T.)
| | - Koji Osuka
- Department of Neurological Surgery, Aichi Medical University, Aichi 480-1195, Japan;
| | - Tsuyoshi Takata
- Department of Pharmacology, Showa Pharmaceutical University, Machida, Tokyo 194-8543, Japan; (S.A.); (T.T.); (Y.T.)
- Department of Environmental Health Sciences and Molecular Toxicology, Graduate School of Medicine, Tohoku University, Miyagi 980-8575, Japan
| | - Yukihiro Tsuchiya
- Department of Pharmacology, Showa Pharmaceutical University, Machida, Tokyo 194-8543, Japan; (S.A.); (T.T.); (Y.T.)
| | - Yasuo Watanabe
- Department of Pharmacology, Showa Pharmaceutical University, Machida, Tokyo 194-8543, Japan; (S.A.); (T.T.); (Y.T.)
- Correspondence:
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7
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Li C, Su C, Wang Z, Han R, Wang Y, Wang H, Tian J, Gao Y. WITHDRAWN: PCC-0105002, a novel small molecule inhibitor of PSD95-nNOS protein-protein interactions, attenuates neuropathic pain and corrects motor coordination-associated side effects in neuropathic pain model. Toxicol Appl Pharmacol 2020:115208. [PMID: 32828906 DOI: 10.1016/j.taap.2020.115208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Revised: 08/06/2020] [Accepted: 08/18/2020] [Indexed: 11/28/2022]
Abstract
This article has been withdrawn at the request of the author(s) and/or editor. The Publisher apologizes for any inconvenience this may cause. The full Elsevier Policy on Article Withdrawal can be found at https://www.elsevier.com/about/our-business/policies/article-withdrawal.
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Affiliation(s)
- Chunmei Li
- School of Pharmacy, Key Laboratory of Molecular Pharmacology and Drug Evaluation (Yantai University), Ministry of Education, Collaborative Innovation Center of Advanced Drug Delivery System and Biotech Drugs in Universities of Shandong, Yantai University, Yantai, China
| | - Chunyu Su
- School of Pharmacy, Key Laboratory of Molecular Pharmacology and Drug Evaluation (Yantai University), Ministry of Education, Collaborative Innovation Center of Advanced Drug Delivery System and Biotech Drugs in Universities of Shandong, Yantai University, Yantai, China
| | - Zhezhe Wang
- School of Pharmacy, Key Laboratory of Molecular Pharmacology and Drug Evaluation (Yantai University), Ministry of Education, Collaborative Innovation Center of Advanced Drug Delivery System and Biotech Drugs in Universities of Shandong, Yantai University, Yantai, China
| | - Rui Han
- School of Pharmacy, Key Laboratory of Molecular Pharmacology and Drug Evaluation (Yantai University), Ministry of Education, Collaborative Innovation Center of Advanced Drug Delivery System and Biotech Drugs in Universities of Shandong, Yantai University, Yantai, China
| | - Yu Wang
- School of Pharmacy, Key Laboratory of Molecular Pharmacology and Drug Evaluation (Yantai University), Ministry of Education, Collaborative Innovation Center of Advanced Drug Delivery System and Biotech Drugs in Universities of Shandong, Yantai University, Yantai, China
| | - Hongbo Wang
- School of Pharmacy, Key Laboratory of Molecular Pharmacology and Drug Evaluation (Yantai University), Ministry of Education, Collaborative Innovation Center of Advanced Drug Delivery System and Biotech Drugs in Universities of Shandong, Yantai University, Yantai, China
| | - Jingwei Tian
- School of Pharmacy, Key Laboratory of Molecular Pharmacology and Drug Evaluation (Yantai University), Ministry of Education, Collaborative Innovation Center of Advanced Drug Delivery System and Biotech Drugs in Universities of Shandong, Yantai University, Yantai, China.
| | - Yonglin Gao
- School of Life Science, Yantai University, Yantai 264005, China.
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8
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Ba M, Ding W, Guan L, Lv Y, Kong M. S-nitrosylation of Src by NR2B-nNOS signal causes Src activation and NR2B tyrosine phosphorylation in levodopa-induced dyskinetic rat model. Hum Exp Toxicol 2018; 38:303-310. [PMID: 30350722 DOI: 10.1177/0960327118806633] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Abnormality in Src PSD-95 NR2B signaling complex assemble occurs in levodopa-induced dyskinesia (LID). N-methyl-D-aspartate receptor (NMDAR) subunit NR2B tyrosine phosphorylation mediated by Src family protein tyrosine kinases is closely associated with dyskinesia. Src autophosphorylation (p-Src) is an important part of Src-catalyzed phosphorylation of NR2B. In addition, the neuronal nitric oxide synthase (nNOS)-derived NO (nNOS/NO) signal which was also involved in dyskinesia recently was proved to participate in the regulation of Src function. Yet, the detailed signal mechanism about the interactions of NR2B, nNOS, and Src is still unknown. In the present study, we investigated the influences of nNOS on Src activation and NR2B tyrosine phosphorylation in dyskinetic rat model by immunoblotting and immunoprecipitation. The results demonstrated that chronic levodopa treatment resulted in downregulation of p-nNOS-S847, one marker of nNOS overactivation. Coinstantaneously, the S-nitrosylation (SNO-Src) and autophosphorylation (p-Src) of Src and NR2B tyrosine phosphorylation were upregulated in dyskinetic rat model. Conversely, administration of 7-NI, one nNOS inhibitor, reversed all these effects of levodopa treatment. Besides, NR2B-containing NMDAR (NR2B/NMDAR) antagonist CP-101,606 could upregulate p-nNOS-S847 and thus attenuate nNOS activation and simultaneously reduce the SNO-Src, p-Src, and NR2B tyrosine phosphorylation. Taken together, the S-nitrosylation of Src is caused by nNOS/NO signal, which is overactivated via Ca2+ influx dependent on NR2B/NMDAR, and subsequently facilitates Src auto-tyrosine phosphorylation and further phosphorylates NR2B. The "NR2B/NMDAR-nNOS/NO-SNO-Src-p-Src-NR2B/NMDAR" signaling cycle may be the molecular basis of NR2B tyrosine phosphorylation upward positive feedback, which demonstrates the possibility as one latent target for dyskinesia therapy.
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Affiliation(s)
- M Ba
- 1 Department of Neurology, the Affiliated Yantai Yuhuangding Hospital of Qingdao University, Shandong, China
| | - W Ding
- 2 Department of Health, the Affiliated Yantai Yuhuangding Hospital of Qingdao University, Shandong, China
| | - L Guan
- 1 Department of Neurology, the Affiliated Yantai Yuhuangding Hospital of Qingdao University, Shandong, China
| | - Y Lv
- 1 Department of Neurology, the Affiliated Yantai Yuhuangding Hospital of Qingdao University, Shandong, China
| | - M Kong
- 3 Department of Neurology, Yantaishan Hospital, Yantai City, Shandong, China
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9
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Effects of Dimeric PSD-95 Inhibition on Excitotoxic Cell Death and Outcome After Controlled Cortical Impact in Rats. Neurochem Res 2017; 42:3401-3413. [PMID: 28828633 DOI: 10.1007/s11064-017-2381-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Revised: 08/02/2017] [Accepted: 08/08/2017] [Indexed: 12/20/2022]
Abstract
Therapeutic effects of PSD-95 inhibition have been demonstrated in numerous studies of stroke; however only few studies have assessed the effects of PSD-95 inhibitors in traumatic brain injury (TBI). As the pathophysiology of TBI partially overlaps with that of stroke, PSD-95 inhibition may also be an effective therapeutic strategy in TBI. The objectives of the present study were to assess the effects of a dimeric inhibitor of PSD-95, UCCB01-144, on excitotoxic cell death in vitro and outcome after experimental TBI in rats in vivo. In addition, the pharmacokinetic parameters of UCCB01-144 were investigated in order to assess uptake of the drug into the central nervous system of rats. After a controlled cortical impact rats were randomized to receive a single injection of either saline or two different doses of UCCB01-144 (10 or 20 mg/kg IV) immediately after injury. Spatial learning and memory were assessed in a water maze at 2 weeks post-trauma, and at 4 weeks lesion volumes were estimated. Overall, UCCB01-144 did not protect against NMDA-toxicity in neuronal cultures or experimental TBI in rats. Important factors that should be investigated further in future studies assessing the effects of PSD-95 inhibitors in TBI are discussed.
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10
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Sommer JB, Bach A, Malá H, Strømgaard K, Mogensen J, Pickering DS. In vitro and in vivo effects of a novel dimeric inhibitor of PSD-95 on excitotoxicity and functional recovery after experimental traumatic brain injury. Eur J Neurosci 2016; 45:238-248. [PMID: 27859797 DOI: 10.1111/ejn.13483] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Revised: 11/03/2016] [Accepted: 11/11/2016] [Indexed: 02/06/2023]
Abstract
PSD-95 inhibitors have been shown to be neuroprotective in stroke, but have only to a very limited extent been evaluated in the treatment of traumatic brain injury (TBI) that has pathophysiological mechanisms in common with stroke. The aims of the current study were to assess the effects of a novel dimeric inhibitor of PSD-95, UCCB01-147, on histopathology and long-term cognitive outcome after controlled cortical impact (CCI) in rats. As excitotoxic cell death is thought to be a prominent part of the pathophysiology of TBI, we also investigated the neuroprotective effects of UCCB01-147 and related compounds on NMDA-induced cell death in cultured cortical neurons. Anesthetized rats were given a CCI or sham injury, and were randomized to receive an injection of either UCCB01-147 (10 mg/kg), the non-competitive NMDAR-receptor antagonist MK-801 (1 mg/kg) or saline immediately after injury. At 2 and 4 weeks post-trauma, spatial learning and memory were assessed in a water maze, and at 3 months, brains were removed for estimation of lesion volumes. Overall, neither treatment with UCCB01-147 nor MK-801 resulted in significant improvements of cognition and histopathology after CCI. Although MK-801 provided robust neuroprotection against NMDA-induced toxicity in cultured cortical neurons, UCCB01-147 failed to reduce cell death and became neurotoxic at high doses. The data suggest potential differential effects of PSD-95 inhibition in stroke and TBI that should be investigated further in future studies taking important experimental factors such as timing of treatment, dosage, and anesthesia into consideration.
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Affiliation(s)
- Jens Bak Sommer
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Jagtvej 160, DK-2100, Copenhagen, Denmark.,The Unit for Cognitive Neuroscience (UCN), Department of Psychology, Faculty of Social Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Anders Bach
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Jagtvej 160, DK-2100, Copenhagen, Denmark
| | - Hana Malá
- The Unit for Cognitive Neuroscience (UCN), Department of Psychology, Faculty of Social Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Kristian Strømgaard
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Jagtvej 160, DK-2100, Copenhagen, Denmark
| | - Jesper Mogensen
- The Unit for Cognitive Neuroscience (UCN), Department of Psychology, Faculty of Social Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Darryl S Pickering
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Jagtvej 160, DK-2100, Copenhagen, Denmark
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11
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Shao S, Xu M, Zhou J, Ge X, Chen G, Guo L, Luo L, Li K, Zhu Z, Zhang F. Atorvastatin Attenuates Ischemia/Reperfusion-Induced Hippocampal Neurons Injury Via Akt-nNOS-JNK Signaling Pathway. Cell Mol Neurobiol 2016; 37:753-762. [PMID: 27488855 DOI: 10.1007/s10571-016-0412-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Accepted: 07/29/2016] [Indexed: 12/29/2022]
Abstract
Ischemia-induced brain damage leads to apoptosis like delayed neuronal death in selectively vulnerable regions, which could further result in irreversible damages. Previous studies have demonstrated that neurons in the CA1 area of hippocampus are particularly sensitive to ischemic damage. Atorvastatin (ATV) has been reported to attenuate cognitive deficits after stroke, but precise mechanism for neuroprotection remains unknown. Therefore, the aims of this study were to investigate the neuroprotective mechanisms of ATV against ischemic brain injury induced by cerebral ischemia reperfusion. In this study, four-vessel occlusion model was established in rats with cerebral ischemia. Rats were divided into five groups: sham group, I/R group, I/R+ATV group, I/R+ATV+LY, and I/R+SP600125 group. Cresyl violet staining was carried out to examine the neuronal death of hippocampal CA1 region. Immunoblotting was used to detect the expression of the related proteins. Results showed that ATV significantly protected hippocampal CA1 pyramidal neurons against cerebral I/R. ATV could increase the phosphorylation of protein kinase B (Akt1) and nNOS, diminished the phosphorylation of JNK3 and c-Jun, and further inhibited the activation of caspase-3. Whereas, all of the aforementioned effects of ATV were reversed by LY294002 (an inhibitor of Akt1). Furthermore, pretreatment with SP600125 (an inhibitor of JNK) diminished the phosphorylation of JNK3 and c-Jun, and further inhibited the activation of caspase-3 after cerebral I/R. Taken together, our results implied that Akt-mediated phosphorylation of nNOS is involved in the neuroprotection of ATV against ischemic brain injury via suppressing JNK3 signaling pathway that provide a new experimental foundation for stroke therapy.
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Affiliation(s)
- Sen Shao
- The Xixi Hospital of Hangzhou Affiliated to Zhejiang University of Traditional Chinese Medicine, Hangzhou, Zhejiang, 310023, People's Republic of China. .,Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou, Jiangsu, 221004, People's Republic of China. .,Jiangsu Key Laboratory of Brain Disease Bioinformation, Xuzhou Medical University, Xuzhou, Jiangsu, 221004, People's Republic of China.
| | - Mingwei Xu
- The First Affiliated Hospital of Zhejiang University, Hangzhou, Zhejiang, 310058, People's Republic of China
| | - Jiajun Zhou
- The Xixi Hospital of Hangzhou Affiliated to Zhejiang University of Traditional Chinese Medicine, Hangzhou, Zhejiang, 310023, People's Republic of China
| | - Xiaoling Ge
- The Xixi Hospital of Hangzhou Affiliated to Zhejiang University of Traditional Chinese Medicine, Hangzhou, Zhejiang, 310023, People's Republic of China
| | - Guanfeng Chen
- The Xixi Hospital of Hangzhou Affiliated to Zhejiang University of Traditional Chinese Medicine, Hangzhou, Zhejiang, 310023, People's Republic of China
| | - Lili Guo
- The Xixi Hospital of Hangzhou Affiliated to Zhejiang University of Traditional Chinese Medicine, Hangzhou, Zhejiang, 310023, People's Republic of China
| | - Lian Luo
- The Xixi Hospital of Hangzhou Affiliated to Zhejiang University of Traditional Chinese Medicine, Hangzhou, Zhejiang, 310023, People's Republic of China
| | - Kun Li
- The Xixi Hospital of Hangzhou Affiliated to Zhejiang University of Traditional Chinese Medicine, Hangzhou, Zhejiang, 310023, People's Republic of China
| | - Zhou Zhu
- The Xixi Hospital of Hangzhou Affiliated to Zhejiang University of Traditional Chinese Medicine, Hangzhou, Zhejiang, 310023, People's Republic of China
| | - Fayong Zhang
- Department of Neurosurgery, Huashan Hospital Affiliated to Fudan University, Shanghai, 200040, People's Republic of China.
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12
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Wang M, Qi DS, Zhou C, Han D, Li PP, Zhang F, Zhou XY, Han M, Di JH, Ye JS, Yu HM, Song YJ, Zhang GY. Ischemic preconditioning protects the brain against injury via inhibiting CaMKII-nNOS signaling pathway. Brain Res 2016; 1634:140-149. [PMID: 26794251 DOI: 10.1016/j.brainres.2016.01.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Revised: 12/31/2015] [Accepted: 01/06/2016] [Indexed: 01/23/2023]
Abstract
Although studies have shown that cerebral ischemic preconditioning (IPC) can ameliorate ischemia/reperfusion (I/R) induced brain damage, but its precise mechanisms remain unknown. Therefore, the aim of this study was to investigate the neuroprotective mechanisms of IPC against ischemic brain damage induced by cerebral I/R and to explore whether the Calcium/calmodulin-dependent protein kinase II (CaMKII)-mediated up-regulation of nNOS ser847-phosphorylation signaling pathway contributed to the protection provided by IPC. Transient global brain ischemia was induced by 4-vessel occlusion in adult male Sprague-Dawley rats. The rats were pretreated with 3 min of IPC alone or KN62 (selective antagonist of CaMKII) treatment before IPC, after reperfusion for 3 days, 6 min ischemia was induced. Cresyl violet staining was used to examine the survival of hippocampal CA1 pyramidal neurons. Immunoblotting was performed to measure the phosphorylation of CaMKII, nNOS, c-Jun and the expression of FasL. Immunoprecipitation was used to examine the binding between PSD95 and nNOS. The results showed that IPC could significantly protect neurons against cerebral I/R injury, furthermore, the combination of PSD95 and nNOS was increased, coinstantaneously the phosphorylation of CaMKII and nNOS (ser847) were up-regulated, however the activation of c-Jun and FasL were reduced. Conversely, KN62 treatment before IPC reversed all these effects of IPC. Taken together, the results suggest that IPC could diminish ischemic brain injury through CaMKII-mediated up-regulation of nNOS ser847-phosphorylation signaling pathway.
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Affiliation(s)
- Mei Wang
- Jiangsu Key Laboratory of Brain Disease Bioinformation, Xuzhou Medical College, Xuzhou, Jiangsu 221004, PR China; Laboratory of Morphology, Xuzhou Medical College, Xuzhou, Jiangsu 221004, PR China
| | - Da-Shi Qi
- Jiangsu Key Laboratory of Brain Disease Bioinformation, Xuzhou Medical College, Xuzhou, Jiangsu 221004, PR China; Department of Genetics, Xuzhou Medical College, Xuzhou, Jiangsu 221004, PR China
| | - Cui Zhou
- Jiangsu Key Laboratory of Brain Disease Bioinformation, Xuzhou Medical College, Xuzhou, Jiangsu 221004, PR China
| | - Dong Han
- Jiangsu Key Laboratory of Brain Disease Bioinformation, Xuzhou Medical College, Xuzhou, Jiangsu 221004, PR China
| | - Pei-Pei Li
- Department of Endocrine, Affiliated Hospital of Xuzhou Medical College, Xuzhou, Jiangsu 221002, PR China
| | - Fang Zhang
- Laboratory of Morphology, Xuzhou Medical College, Xuzhou, Jiangsu 221004, PR China
| | - Xiao-Yan Zhou
- Laboratory of Morphology, Xuzhou Medical College, Xuzhou, Jiangsu 221004, PR China
| | - Meng Han
- Department of Orthopaedics, Xuzhou Central Hospital, Xuzhou, Jiangsu 221009, PR China
| | - Jie-Hui Di
- Jiangsu Key Laboratory of Brain Disease Bioinformation, Xuzhou Medical College, Xuzhou, Jiangsu 221004, PR China
| | - Jun-Song Ye
- Jiangsu Key Laboratory of Brain Disease Bioinformation, Xuzhou Medical College, Xuzhou, Jiangsu 221004, PR China
| | - Hong-Min Yu
- Jiangsu Key Laboratory of Brain Disease Bioinformation, Xuzhou Medical College, Xuzhou, Jiangsu 221004, PR China
| | - Yuan-Jian Song
- Jiangsu Key Laboratory of Brain Disease Bioinformation, Xuzhou Medical College, Xuzhou, Jiangsu 221004, PR China; Department of Genetics, Xuzhou Medical College, Xuzhou, Jiangsu 221004, PR China.
| | - Guang-Yi Zhang
- Jiangsu Key Laboratory of Brain Disease Bioinformation, Xuzhou Medical College, Xuzhou, Jiangsu 221004, PR China.
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13
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Possible interaction of hippocampal nitric oxide and calcium/calmodulin-dependent protein kinase II on reversal of spatial memory impairment induced by morphine. Eur J Pharmacol 2015; 751:99-111. [DOI: 10.1016/j.ejphar.2015.01.042] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Revised: 01/19/2015] [Accepted: 01/21/2015] [Indexed: 01/24/2023]
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14
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The possible mechanism of Parkinson's disease progressive damage and the preventive effect of GM1 in the rat model induced by 6-hydroxydopamine. Brain Res 2014; 1592:73-81. [PMID: 25285892 DOI: 10.1016/j.brainres.2014.09.053] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2014] [Revised: 09/18/2014] [Accepted: 09/23/2014] [Indexed: 01/15/2023]
Abstract
The progressive pathogenesis and prevention of Parkinson's disease (PD) remains unknown at present. Therefore, the present study aimed to investigate the possible progressive pathogenesis and prevention of PD. Our study investigated the content of glutamate, mitochondria calcium, calmodulin, malonaldehyde and trace elements in striatum, cerebral cortex and hippocampus tissues; and the expression of bcl-2, bax and neuronal nitric oxide synthase (nNOS) in substantia nigra and striatum; and the change of apomorphine induced rotation behavior; and the treatmental effect of monosialotetrahexosylganglioside (GM1) intraperitoneal administration for 14 days in a PD rat model induced by 6-hydroxydopamine. The results revealed that the content of glutamate significantly decreased, and that of mitochondria calcium, calmodulin, malonaldehyde and ferrum significantly increased in striatum, cerebral cortex and hippocampus tissues; the content of magnesium significantly decreased, and that of cuprum and zinc significantly increased in cerebral cortex; the expression of bcl-2 significantly decreased, and that of bax and nNOS significantly increased in substantia nigra and striatum in PD rat. GM1 can partially improve the apomorphine induced rotation behavior and changes of glutamate, mitochondria calcium, calmodulin content in striatum of PD rat. Data suggested that dysfunction of excitatory amino acids neurotransmitter, calcium homeostasis disorder, abnormal metabolism of oxygen free radicals, abnormal trace elements distribution and/or deposition and excessive apoptosis participated in the progressive process of PD, and that GM1 could partially prevent the progressive damage.
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15
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Redox signal regulation via nNOS phosphorylation at Ser847 in PC12 cells and rat cerebellar granule neurons. Biochem J 2014; 459:251-63. [PMID: 24499461 DOI: 10.1042/bj20131262] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Phosphorylation is considered a main mechanism modulating nNOS (neuronal nitric oxide synthase) function to reduce NO production. In the present study, the effects of nNOS phosphorylation on redox signalling, including that of NO, ROS (reactive oxygen species), and 8-nitro-cGMP (8-nitroguanosine 3',5'-cyclic monophosphate), a downstream messenger of redox signalling, were investigated. In vitro experiments revealed that a phosphorylation-mimic mutant of nNOS (Ser847 replaced with aspartic acid, 847D) increased uncoupling to produce a superoxide. In addition, nicotine, which triggers an influx of Ca2+, induced more ROS and 8-nitro-cGMP production in 847D-expressing PC12 cells than WT (wild-type)-expressing cells. Additionally, nicotine-induced phosphorylation of nNOS at Ser847 and increased ROS and 8-nitro-cGMP production in rat CGNs (cerebellar granule neurons). In CGNs, the NOS (nitric oxide synthase) inhibitor L-NAME (NG-nitro-L-arginine methyl ester) and superoxide dismutase completely inhibited ROS and 8-nitro-cGMP production, whereas the CaMK (Ca2+/calmodulin-dependent protein kinase) inhibitor KN93 mildly reduced this effect. Nicotine induced HO-1 (haem oxygenase 1) expression in CGNs and showed cytoprotective effects against apoptosis. Moreover, 8-nitro-cGMP treatment showed identical effects that were attenuated by KN93 pre-treatment. The present paper provides the first substantial corroboration for the biological effects of nNOS phosphorylation at Ser847 on redox signalling, including ROS and intracellular 8-nitro-cGMP generation in neurons, which possibly play roles in neuroprotection.
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Coultrap SJ, Bayer KU. Nitric oxide induces Ca2+-independent activity of the Ca2+/calmodulin-dependent protein kinase II (CaMKII). J Biol Chem 2014; 289:19458-65. [PMID: 24855644 DOI: 10.1074/jbc.m114.558254] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Both signaling by nitric oxide (NO) and by the Ca(2+)/calmodulin (CaM)-dependent protein kinase II α isoform (CaMKIIα) are implicated in two opposing forms of synaptic plasticity underlying learning and memory, as well as in excitotoxic/ischemic neuronal cell death. For CaMKIIα, these functions specifically involve also Ca(2+)-independent autonomous activity, traditionally generated by Thr-286 autophosphorylation. Here, we demonstrate that NO-induced S-nitrosylation of CaMKIIα also directly generated autonomous activity, and that CaMKII inhibition protected from NO-induced neuronal cell death. NO induced S-nitrosylation at Cys-280/289, and mutation of either site abolished autonomy, indicating that simultaneous nitrosylation at both sites was required. Additionally, autonomy was generated only when Ca(2+)/CaM was present during NO exposure. Thus, generation of this form of CaMKIIα autonomy requires simultaneous signaling by NO and Ca(2+). Nitrosylation also significantly reduced subsequent CaMKIIα autophosphorylation specifically at Thr-286, but not at Thr-305. A previously described reduction of CaMKII activity by S-nitrosylation at Cys-6 was also observed here, but only after prolonged (>5 min) exposure to NO donors. These results demonstrate a novel regulation of CaMKII by another second messenger system and indicate its involvement in excitotoxic neuronal cell death.
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Affiliation(s)
- Steven J Coultrap
- From the Department of Pharmacology, Anschutz Medical Campus, University of Colorado School of Medicine, Aurora, Colorado 80045
| | - K Ulrich Bayer
- From the Department of Pharmacology, Anschutz Medical Campus, University of Colorado School of Medicine, Aurora, Colorado 80045
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17
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N-methyl-D-aspartate receptor-dependent denitrosylation of neuronal nitric oxide synthase increase the enzyme activity. PLoS One 2012; 7:e52788. [PMID: 23285183 PMCID: PMC3532120 DOI: 10.1371/journal.pone.0052788] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2012] [Accepted: 11/21/2012] [Indexed: 11/19/2022] Open
Abstract
Our laboratory once reported that neuronal nitric oxide synthase (nNOS) S-nitrosylation was decreased in rat hippocampus during cerebral ischemia-reperfusion, but the underlying mechanism was unclear. In this study, we show that nNOS activity is dynamically regulated by S-nitrosylation. We found that overexpressed nNOS in HEK293 (human embryonic kidney) cells could be S-nitrosylated by exogenous NO donor GSNO and which is associated with the enzyme activity decrease. Cys331, one of the zinc-tetrathiolate cysteines, was identified as the key site of nNOS S-nitrosylation. In addition, we also found that nNOS is highly S-nitrosylated in resting rat hippocampal neurons and the enzyme undergos denitrosylation during the process of rat brain ischemia/reperfusion. Intrestingly, the process of nNOS denitrosylation is coupling with the decrease of nNOS phosphorylation at Ser847, a site associated with nNOS activation. Further more, we document that nNOS denitrosylation could be suppressed by pretreatment of neurons with MK801, an antagonist of NMDAR, GSNO, EGTA, BAPTA, W-7, an inhibitor of calmodulin as well as TrxR1 antisense oligonucleotide (AS-ODN) respectively. Taken together, our data demonstrate that the denitrosylation of nNOS induced by calcium ion influx is a NMDAR-dependent process during the early stage of ischemia/reperfusion, which is majorly mediated by thioredoxin-1 (Trx1) system. nNOS dephosphorylation may be induced by the enzyme denitrosylation, which suggest that S-nitrosylation/denitrosylation of nNOS may be an important mechanism in regulating the enzyme activity.
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18
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Cyclic AMP-dependent phosphorylation of neuronal nitric oxide synthase mediates penile erection. Proc Natl Acad Sci U S A 2012; 109:16624-9. [PMID: 23012472 DOI: 10.1073/pnas.1213790109] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Nitric oxide (NO) generated by neuronal NO synthase (nNOS) initiates penile erection, but has not been thought to participate in the sustained erection required for normal sexual performance. We now show that cAMP-dependent phosphorylation of nNOS mediates erectile physiology, including sustained erection. nNOS is phosphorylated by cAMP-dependent protein kinase (PKA) at serine(S)1412. Electrical stimulation of the penile innervation increases S1412 phosphorylation that is blocked by PKA inhibitors but not by PI3-kinase/Akt inhibitors. Stimulation of cAMP formation by forskolin also activates nNOS phosphorylation. Sustained penile erection elicited by either intracavernous forskolin injection, or augmented by forskolin during cavernous nerve electrical stimulation, is prevented by the NOS inhibitor L-NAME or in nNOS-deleted mice. Thus, nNOS mediates both initiation and maintenance of penile erection, implying unique approaches for treating erectile dysfunction.
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19
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Cerebral white matter oxidation and nitrosylation in young rodents with kaolin-induced hydrocephalus. J Neuropathol Exp Neurol 2012; 71:274-88. [PMID: 22437339 DOI: 10.1097/nen.0b013e31824c1b44] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Hydrocephalus is associated with reduced blood flow in periventricular white matter. To investigate hypoxic and oxidative damage in the brains of rats with hydrocephalus, kaolin was injected into the cisterna magna of newborn 7- and 21-day-old Sprague-Dawley rats, and ventricle size was assessed by magnetic resonance imaging at 7, 21, and 42 days of age. In-situ evidence of hypoxia in periventricular capillaries and glial cells was shown by pimonidazole hydrochloride binding. Biochemical assay of thiobarbituric acid reaction and immunohistochemical detection of malondialdehyde and 4-hydroxy-2-nonenal indicated the presence of lipid peroxidation in white matter. Biochemical assay of nitrite indicated increased nitric oxide production. Nitrotyrosine immunohistochemistry showed nitrosylated proteins in white matter reactive microglia and astrocytes. Activities of the antioxidant enzymes catalase and glutathione peroxidase were not increased, and altered hypoxia-inducible factor 1α was not detected by quantitative reverse transcription-polymerase chain reaction. Cerebral vascular endothelial growth factor expression determined by quantitative reverse transcription-polymerase chain reaction and enzyme-linked immunosorbent assay was not changed, but vascular endothelial growth factor immunoreactivity was increased in reactive astrocytes of hydrocephalic white matter. To determine if nitric oxide synthase is involved in the pathogenesis, we induced hydrocephalus in 7-day-old wild-type and neuronal nitric oxide synthase-deficient mice. At 7 days, the wild-type and mutant mice exhibited equally severe ventriculomegaly and no behavioral differences, although increased glial fibrillary acidic protein was less in the mutant mice. We conclude that hypoxia, via peroxidation and nitrosylation, contributes to brain changes in young rodents with hydrocephalus and that compensatory mechanisms are negligible.
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20
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A mathematical model for astrocytes mediated LTP at single hippocampal synapses. J Comput Neurosci 2012; 33:341-70. [PMID: 22454034 DOI: 10.1007/s10827-012-0389-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2011] [Revised: 02/21/2012] [Accepted: 02/22/2012] [Indexed: 02/07/2023]
Abstract
Many contemporary studies have shown that astrocytes play a significant role in modulating both short and long form of synaptic plasticity. There are very few experimental models which elucidate the role of astrocyte over Long-term Potentiation (LTP). Recently, Perea and Araque (Science 317:1083-1086, 2007) demonstrated a role of astrocytes in induction of LTP at single hippocampal synapses. They suggested a purely pre-synaptic basis for induction of this N-methyl-D-Aspartate (NMDA) Receptor-independent LTP. Also, the mechanisms underlying this pre-synaptic induction were not investigated. Here, in this article, we propose a mathematical model for astrocyte modulated LTP which successfully imitates the experimental findings of Perea and Araque (Science 317:1083-1086, 2007). Our study suggests the role of retrograde messengers, possibly Nitric Oxide (NO), for this pre-synaptically modulated LTP.
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21
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Doucet MV, Harkin A, Dev KK. The PSD-95/nNOS complex: new drugs for depression? Pharmacol Ther 2011; 133:218-29. [PMID: 22133842 DOI: 10.1016/j.pharmthera.2011.11.005] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2011] [Accepted: 11/02/2011] [Indexed: 12/11/2022]
Abstract
Drug treatment of major depressive disorder is currently limited to the use of agents which influence monoaminergic neuronal transmission including inhibitors of presynaptic transporters and monoamine oxidase. Typically improvement in depressive symptoms only emerges after several weeks of treatment, suggesting that downstream neuronal adaptations rather than the elevation in synaptic monoamine levels are responsible for antidepressant effects. In recent years, the NMDA receptor has emerged as a promising target for treating CNS disorders including stroke, pain and depression. In this review, we outline the molecular mechanisms underlying NMDA receptor signalling in neurons and in particular provide an overview of the role of the NMDAR/PSD-95/nNOS complex in CNS disorders. We discuss novel drug developments made that suggest the NMDAR/PSD-95/nNOS complex as a potential target for the treatment of depression. The review also provides examples of how PDZ-based protein-protein interactions can be exploited as novel drug targets for disease.
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Affiliation(s)
- Marika V Doucet
- Molecular Neuropharmacology, Department of Physiology, Trinity College, Dublin 2, Ireland
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22
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23
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Reactive nitroxidative species and nociceptive processing: determining the roles for nitric oxide, superoxide, and peroxynitrite in pain. Amino Acids 2010; 42:75-94. [PMID: 20552384 DOI: 10.1007/s00726-010-0633-0] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2010] [Accepted: 05/15/2010] [Indexed: 12/12/2022]
Abstract
Pain is a multidimensional perception and is modified at distinct regions of the neuroaxis. During enhanced pain, neuroplastic changes occur in the spinal and supraspinal nociceptive modulating centers and may result in a hypersensitive state termed central sensitization, which is thought to contribute to chronic pain states. Central sensitization culminates in hyperexcitability of dorsal horn nociceptive neurons resulting in increased nociceptive transmission and pain perception. This state is associated with enhanced nociceptive signaling, spinal glutamate-mediated N-methyl-D: -aspartate receptor activation, neuroimmune activation, nitroxidative stress, and supraspinal descending facilitation. The nitroxidative species considered for their role in nociception and central sensitization include nitric oxide (NO), superoxide ([Formula: see text]), and peroxynitrite (ONOO(-)). Nitroxidative species are implicated during persistent but not normal nociceptive processing. This review examines the role of nitroxidative species in pain through a discussion of their contributions to central sensitization and the underlying mechanisms. Future directions for nitroxidative pain research are also addressed. As more selective pharmacologic agents are developed to target nitroxidative species, the exact role of nitroxidative species in pain states will be better characterized and should offer promising alternatives to available pain management options.
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24
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Corso-Díaz X, Krukoff TL. nNOS alpha and nNOS beta localization to aggresome-like inclusions is dependent on HSP90 activity. J Neurochem 2010; 114:864-72. [PMID: 20492351 DOI: 10.1111/j.1471-4159.2010.06813.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Nitric oxide (NO) is a highly reactive gas that participates in many physiological processes including neuroplasticity and neuronal survival. In brain neurons, NO is produced by two variants of neuronal nitric oxide synthase (nNOS), nNOSalpha and nNOSbeta. The activity of nNOSalpha is tightly regulated at the transcriptional and post-transcriptional levels. Heat shock protein 90 (HSP90) regulates nNOSalpha activity by facilitating heme insertion into the nNOSalpha monomer, resulting in increased NO production. HSP90 also regulates nNOSalpha degradation through the proteasome pathway. Here, we show in vitro that inhibition of HSP90 with geldanamycin increases nNOS mobility and induces formation of aggresome-like inclusions containing both nNOSalpha and nNOSbeta in primary cortical neurons. We also report the formation of endogenous nNOS-containing aggresome-like inclusions in healthy, untreated, mature primary cortical neurons. We propose that nNOS aggregation may be an additional mechanism for regulating nNOS activity, as has been proposed for inducible nitric oxide synthase. These findings reveal a new role for HSP90 in regulating nNOS sub-cellular localization and underscore the complexity of nNOS regulatory mechanisms.
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Affiliation(s)
- Ximena Corso-Díaz
- Center for Neuroscience, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, Alberta, Canada
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25
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Abstract
The formation and function of the neuronal synapse is dependent on the asymmetric distribution of proteins both presynaptically and postsynaptically. Recently, proteins important in establishing cellular polarity have been implicated in the synapse. We therefore performed a proteomic screen with known polarity proteins and identified novel complexes involved in synaptic function. Specifically, we show that the tumor suppressor protein, Scribble, associates with neuronal nitric oxide synthase (nNOS) adaptor protein (NOS1AP) [also known as C-terminal PDZ ligand of nNOS (CAPON)] and is found both presynaptically and postsynaptically. The Scribble-NOS1AP association is direct and is mediated through the phosphotyrosine-binding (PTB) domain of NOS1AP and the fourth PDZ domain of Scribble. Further, we show that Scribble bridges NOS1AP to a beta-Pix [beta-p21-activated kinase (PAK)-interacting exchange factor]/Git1 (G-protein-coupled receptor kinase-interacting protein)/PAK complex. The overexpression of NOS1AP leads to an increase in dendritic protrusions, in a fashion that depends on the NOS1AP PTB domain. Consistent with these observations, both full-length NOS1AP and the NOS1AP PTB domain influence Rac activity. Together these data suggest that NOS1AP plays an important role in the mammalian synapse.
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26
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Wang WW, Hu SQ, Li C, Zhou C, Qi SH, Zhang GY. Transduced PDZ1 domain of PSD-95 decreases Src phosphorylation and increases nNOS (Ser847) phosphorylation contributing to neuroprotection after cerebral ischemia. Brain Res 2010; 1328:162-70. [DOI: 10.1016/j.brainres.2010.02.055] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2009] [Revised: 02/17/2010] [Accepted: 02/17/2010] [Indexed: 11/25/2022]
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Postsynaptic density-93 deficiency protects cultured cortical neurons from N-methyl-D-aspartate receptor-triggered neurotoxicity. Neuroscience 2010; 166:1083-90. [PMID: 20097270 DOI: 10.1016/j.neuroscience.2010.01.030] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2009] [Revised: 01/14/2010] [Accepted: 01/14/2010] [Indexed: 11/23/2022]
Abstract
It has been reported that N-methyl-D-aspartate receptor (NMDAR)-triggered neurotoxicity is related to excessive Ca(2+) loading and an increase in nitric oxide (NO) concentration. However, the molecular mechanisms that underlie these events are not completely understood. NMDARs and neuronal NO synthase each binds to the scaffolding protein postsynaptic density (PSD)-93 through its PDZ domains. In this study, we determined whether PSD-93 plays a critical role in NMDAR/Ca(2+)/NO-mediated neurotoxicity. We found that the targeted disruption of the PSD-93 gene attenuated the neurotoxicity triggered by NMDAR activation, but not by non-NMDAR activation, in cultured mouse cortical neurons. PSD-93 deficiency reduced the amount of NMDAR subunits NR2A and NR2B in synaptosomal fractions from the cortical neurons and significantly prevented NMDA-stimulated increases in cyclic guanosine 3',5'-monophosphate and Ca(2+) loading in the cortical neurons. These findings indicate that PSD-93 deficiency could block NMDAR-triggered neurotoxicity by disrupting the NMDAR-Ca(2+)-NO signaling pathway and reducing expression of synaptic NR2A and NR2B. Since NMDARs, Ca(2+), and NO play a critical role during the development of brain trauma, seizures, and ischemia, the present work suggests that PSD-93 might contribute to molecular mechanisms of neuronal damage in these brain disorders.
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Chaudhury A, He XD, Goyal RK. Role of PSD95 in membrane association and catalytic activity of nNOSalpha in nitrergic varicosities in mice gut. Am J Physiol Gastrointest Liver Physiol 2009; 297:G806-13. [PMID: 19679819 PMCID: PMC2763812 DOI: 10.1152/ajpgi.00279.2009] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
We have recently shown that membrane association of neuronal nitric oxide synthase-alpha (nNOSalpha) is critical in the regulation of synthesis of NO during nitrergic neurotransmission. The purpose of this study was to examine the role of the synapse-associated proteins (SAPs) in membrane association of nNOSalpha. Varicosities (swellings on terminal axons) were isolated from mice gastrointestinal tract and examined for nNOSalpha, postsynaptic density protein 95 (PSD95), and membrane interactions by coimmunoprecipitation and SDS-PAGE. Our results show that PSD95 protein was present in the membrane fraction of the nerve varicosity, whereas both PSD95 and SAP97 were present in the cytosol. nNOSalpha was associated with PSD95 but not SAP97. nNOSalpha-PSD95 complex was bound to the membrane via palmitoylation of PSD95. Depalmitoylation of PSD95 with 2-bromopalmitate dislocates nNOSalpha and PSD95 from the varicosity membrane and abolishes NO production. These studies show that palmitoylation of PSD95 anchors nNOSalpha to the varicosity membrane and that it is obligatory for NO production by the enzyme. Palmitoylation of PSD95 may provide a novel target for regulation of nitrergic neurotransmission.
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Affiliation(s)
- Arun Chaudhury
- Center for Swallowing and Motility Disorders, Gastrointestinal Division, Veterans Affairs Boston Healthcare System and Harvard Medical School, Boston, Massachusetts
| | - Xue-Dao He
- Center for Swallowing and Motility Disorders, Gastrointestinal Division, Veterans Affairs Boston Healthcare System and Harvard Medical School, Boston, Massachusetts
| | - Raj K. Goyal
- Center for Swallowing and Motility Disorders, Gastrointestinal Division, Veterans Affairs Boston Healthcare System and Harvard Medical School, Boston, Massachusetts
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Reduced spatial learning in mice treated with NVP-AAM077 through down-regulating neurogenesis. Eur J Pharmacol 2009; 622:37-44. [PMID: 19765576 DOI: 10.1016/j.ejphar.2009.09.031] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2009] [Revised: 09/01/2009] [Accepted: 09/10/2009] [Indexed: 01/17/2023]
Abstract
NR2A-containing N-methyl-D-aspartate (NMDA) receptors have important roles in influencing the long-term potentiation and spatial memory. Here using Morris water maze, we found that inhibition of NR2A-containing NMDA receptors by [(R)-[(S)-1-(4-bromophenyl)-ethylamino]-(2, 3-dioxo-1,2,3,4-tetrahydroquinoxalin-5-yl)-methyl]-phosphonic acid (NVP-AAM077) hindered the formation of spatial memory. An increasing number of reports suggest that adult hippocampal neurogenesis is involved in hippocampal-mediated learning. To explore the possible mechanisms understanding the reduced spatial memory by NVP-AAM077, we investigated the effects of NVP-AAM077 on neurogenesis. We found that NVP-AAM077 inhibited progenitor cells proliferation in the subventricular zone and dentate gyrus and reduced the survival of newborn cells in the dentate gyrus in the adult mice. In null mutant mice lacking neuronal nitric oxide synthase (nNOS) gene (nNOS(-/-)), the effects of NVP-AAM077 on neurogenesis disappeared. In addition, NVP-AAM077 increased nNOS enzymatic activity. Our findings suggest that NVP-AAM077 reduced spatial learning through down-regulating neurogenesis in the adult hippocampus.
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Raveendran R, Devi Suma Priya S, Mayadevi M, Steephan M, Santhoshkumar TR, Cheriyan J, Sanalkumar R, Pradeep KK, James J, Omkumar RV. Phosphorylation status of the NR2B subunit of NMDA receptor regulates its interaction with calcium/calmodulin-dependent protein kinase II. J Neurochem 2009; 110:92-105. [DOI: 10.1111/j.1471-4159.2009.06108.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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31
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Fox K. Experience-dependent plasticity mechanisms for neural rehabilitation in somatosensory cortex. Philos Trans R Soc Lond B Biol Sci 2009; 364:369-81. [PMID: 19038777 PMCID: PMC2674476 DOI: 10.1098/rstb.2008.0252] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Functional rehabilitation of the cortex following peripheral or central nervous system damage is likely to be improved by a combination of behavioural training and natural or therapeutically enhanced synaptic plasticity mechanisms. Experience-dependent plasticity studies in the somatosensory cortex have begun to reveal those synaptic plasticity mechanisms that are driven by sensory experience and might therefore be active during behavioural training. In this review the anatomical pathways, synaptic plasticity mechanisms and structural plasticity substrates involved in cortical plasticity are explored, focusing on work in the somatosensory cortex and the barrel cortex in particular.
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Affiliation(s)
- Kevin Fox
- School of Biosciences, Cardiff University, Museum Avenue, Cardiff CF10 3AX, UK.
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32
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Goebel DJ. Selective blockade of CaMKII-α inhibits NMDA-induced caspase-3-dependent cell death but does not arrest PARP-1 activation or loss of plasma membrane selectivity in rat retinal neurons. Brain Res 2009; 1256:190-204. [DOI: 10.1016/j.brainres.2008.12.051] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2008] [Revised: 12/12/2008] [Accepted: 12/12/2008] [Indexed: 01/08/2023]
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33
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Zhou C, Li C, Yu HM, Zhang F, Han D, Zhang GY. Neuroprotection of gamma-aminobutyric acid receptor agonists via enhancing neuronal nitric oxide synthase (Ser847) phosphorylation through increased neuronal nitric oxide synthase and PSD95 interaction and inhibited protein phosphatase activity in cerebral ischemia. J Neurosci Res 2008; 86:2973-83. [PMID: 18512761 DOI: 10.1002/jnr.21728] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
It is well documented that exitotoxicity induced by N-methyl-D-aspartate (NMDA) receptor activation plays a pivotal role in delayed neuronal death in the hippocampal CA1 region after transient global ischemia. However, the effect of gamma-aminobutyric acid (GABA) receptor activation is uncertain in ischemia brain injury. The aim of this study was to investigate whether the enhancement of GABA receptor activity could inhibit NMDA receptor-mediated nitric oxide (NO) production by neuronal NO synthase (nNOS) in brain ischemic injury. The results showed that both the GABA(A) receptor agonist muscimol and the GABA(B) receptor agonist baclofen had neuroprotective effect, and the combination of two agonists could significantly protect neurons against death induced by ischemia/reperfusion. Coapplication of muscimol with baclofen not only enhanced nNOS (Ser847) phosphorylation but also increased the interaction of nNOS with PSD95 at 6 hr and 1 day of reperfusion. Interestingly, the inhibitors of calcineurin and PP1/PP2A could enhance nNOS phosphorylation at Ser847 site at 1 day of reperfusion after ischemia but not at 6 hr of reperfusion. From these data, we conclude that GABA receptor activation could exert its neuroprotective effect through increasing nNOS (Ser847) phosphorylation by different mechanisms at 6 hr and 1 day of reperfusion. The increased interaction of nNOS and postsynaptic density-95 induced by GABA agonists is responsible for nNOS (Ser847) phosphorylation at both time points, but at 1 day of reperfusion the inhibition of protein phosphatase activity by GABA agonists also contributes to the neuroprotection. Our results suggest that GABA receptor agonists may serve as a potential and important neuroprotectant in therapy for ischemic stroke.
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Affiliation(s)
- Cui Zhou
- Research Center for Biochemistry and Molecular Biology, Xuzhou Medical College, Xuzhou, Jiangsu, China
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Montero F, Portillo F, González-Forero D, Moreno-López B. The nitric oxide/cyclic guanosine monophosphate pathway modulates the inspiratory-related activity of hypoglossal motoneurons in the adult rat. Eur J Neurosci 2008; 28:107-16. [PMID: 18616563 DOI: 10.1111/j.1460-9568.2008.06312.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Motoneurons integrate interneuronal activity into commands for skeletal muscle contraction and relaxation to perform motor actions. Hypoglossal motoneurons (HMNs) are involved in essential motor functions such as breathing, mastication, swallowing and phonation. We have investigated the role of the gaseous molecule nitric oxide (NO) in the regulation of the inspiratory-related activity of HMNs in order to further understand how neural activity is transformed into motor activity. In adult rats, we observed nitrergic fibers and bouton-like structures in close proximity to motoneurons, which normally lack the molecular machinery to synthesize NO. In addition, immunohistochemistry studies demonstrated that perfusion of animals with a NO donor resulted in an increase in the levels of cyclic guanosine monophosphate (cGMP) in motoneurons, which express the soluble guanylyl cyclase (sGC) in the hypoglossal nucleus. Modulators of the NO/cGMP pathway were micro-iontophoretically applied while performing single-unit extracellular recordings in the adult decerebrated rat. Application of a NO synthase inhibitor or a sGC inhibitor induced a statistically significant reduction in the inspiratory-related activity of HMNs. However, excitatory effects were observed by ejection of a NO donor or a cell-permeable analogue of cGMP. In slice preparations, application to the bath of a NO donor evoked membrane depolarization and a decrease in rheobase, which were prevented by co-addition to the bath of a sGC inhibitor. These effects were not prevented by reduction of the spontaneous synaptic activity. We conclude that NO from afferent fibers anterogradely modulates the inspiratory-related activity of HMNs by a cGMP-dependent mechanism in physiological conditions.
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Affiliation(s)
- Fernando Montero
- Area de Fisiología, Facultad de Medicina, Universidad de Cádiz, Plaza Falla 9, 11003 Cádiz, Spain.
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Yu HM, Xu J, Li C, Zhou C, Zhang F, Han D, Zhang GY. Coupling between neuronal nitric oxide synthase and glutamate receptor 6-mediated c-Jun N-terminal kinase signaling pathway via S-nitrosylation contributes to ischemia neuronal death. Neuroscience 2008; 155:1120-32. [PMID: 18676085 DOI: 10.1016/j.neuroscience.2008.03.061] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2008] [Revised: 03/22/2008] [Accepted: 03/25/2008] [Indexed: 10/22/2022]
Abstract
S-nitrosylation, as a post-translational protein modification, recently has been paid more and more attention in stroke research. S-nitrosylation regulates protein function by the mechanisms of covalent attachment that control the addition or the removal of nitric oxide (NO) from a cysteine thiol. The derivation of NO is established by the demonstration that, in cerebral neurons, NO mainly generates from neuronal nitric oxide synthase (nNOS) during the early stages of reperfusion. In the past researches, we demonstrate that global ischemia-reperfusion facilitates the activation of glutamate receptor 6 (GluR6) -mediated c-Jun N-terminal kinase (JNK) signaling pathway. The objective of this study is primarily to determine, during the early stages of reperfusion in rat four-vessel occlusion (4-VO) ischemic model, whether nNOS-derived NO affects the GluR6-mediated JNK signaling route via S-nitrosylation which is performed mainly by the biotin switch assay. Here, we show that administration of 7-nitroindazole, an inhibitor of nNOS, or ketamine, an antagonist of N-methyl-d-aspartate receptor (NMDAR), diminishes the increased S-nitrosylation of GluR6 induced by cerebral ischemia-reperfusion. In contrast, 2-amion-5,6-dihydro-6-methyl-4H-1,3-thiazine, an inhibitor of inducible NO synthase does not affect S-nitrosylation of GluR6. Moreover, treatment with sodium nitroprusside (SNP), an exogenous NO donor, increases the S-nitrosylation and phosphorylation of nNOS, leading to the attenuation of the increased S-nitrosylation of GluR6 and the assembling of GluR6* postsynaptic density protein 95 (PSD95)* mixed lineage kinase 3 (MLK3) signaling module induced by cerebral ischemia-reperfusion. The results also show that GluR6 downstream MLK3* mitogen activated protein kinase kinase 4/7* JNK signaling module and nuclear or non-nuclear apoptosis pathways are involved in the above signaling route. However, dithiothreitol (DTT) antagonizes the neuroprotection of SNP. Treatment with DTT alone, as a negative control, prevents S-nitrosylation of proteins, which indicates the existence of endogenously produced S-nitrosylation. These data suggest that GluR6 is S-nitrosylated by endogenous NO in cerebral ischemia-reperfusion, which is possibly correlated with NMDAR* PSD95* nNOS signaling module, and further activates GluR6* PSD95* MLK3 signaling module and JNK signaling pathway. In contrast, exogenous NO donor antagonizes the above action of endogenous NO generated from nNOS. Thus, our results provide the coupling of nNOS with GluR6 by S-nitrosylation during the early stages of ischemia-reperfusion, which can be a new approach for stroke therapy.
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Affiliation(s)
- H-M Yu
- Research Center for Biochemistry and Molecular Biology, Xuzhou Medical College, Xuzhou 221002, Jiangsu, People's Republic of China
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36
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Nitric oxide-mediated modulation of calcium/calmodulin-dependent protein kinase II. Biochem J 2008; 412:223-31. [DOI: 10.1042/bj20071195] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The mechanisms of NO inhibition of CaMK [Ca2+/CaM (calmodulin)-dependent protein kinase] II activity were studied. In rat pituitary tumour GH3 cells, TRH [thyrotrophin (TSH)-releasing hormone]-stimulated phosphorylation of nNOS [neuronal NOS (NO synthase)] at Ser847 was sensitive to an inhibitor of CaMKs, KN-93, and was enhanced by inhibition of nNOS with 7NI (7-nitroindazole). Enzyme activity of CaMKII following in situ treatment with 7NI was also increased. The in vitro activity of CaMKII was inhibited by co-incubation either with nNOS and L-arginine or with NO donors SNAP (S-nitroso-N-acetyl-DL-penicillamine) and DEA-NONOate [diethylamine-NONOate (diazeniumdiolate)]. Once inhibited by these treatments, CaMKII was observed to undergo full reactivation on the addition of a reducing reagent, DTT (dithiothreitol). In transfected cells expressing CaMKII and nNOS, treatment with the calcium ionophore A23187 further revealed nNOS phosphorylation at Ser847, which was enhanced by 7NI and CaMKII S-nitrosylation. Mutated CaMKII (C6A), in which Cys6 was substituted with an alanine residue, was refractory to 7NI-induced enhancement of nNOS phosphorylation or to CaMKII S-nitrosylation. Furthermore, we could identify Cys6 as a direct target for S-nitrosylation of CaMKII using MS. In addition, treatment with glutamate caused an increase in CaMKII S-nitrosylation in rat hippocampal slices. This glutamate-induced S-nitrosylation was blocked by 7NI. These results suggest that inactivation of CaMKII mediated by S-nitrosylation at Cys6 may contribute to NO-induced neurotoxicity in the brain.
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37
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Ohnishi T, Okuda-Ashitaka E, Matsumura S, Katano T, Nishizawa M, Ito S. Characterization of signaling pathway for the translocation of neuronal nitric oxide synthase to the plasma membrane by PACAP. J Neurochem 2008; 105:2271-85. [DOI: 10.1111/j.1471-4159.2008.05325.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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38
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Fleming I. Biology of Nitric Oxide Synthases. Microcirculation 2008. [DOI: 10.1016/b978-0-12-374530-9.00003-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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39
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González-Forero D, Portillo F, Gómez L, Montero F, Kasparov S, Moreno-López B. Inhibition of resting potassium conductances by long-term activation of the NO/cGMP/protein kinase G pathway: a new mechanism regulating neuronal excitability. J Neurosci 2007; 27:6302-12. [PMID: 17554004 PMCID: PMC6672157 DOI: 10.1523/jneurosci.1019-07.2007] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Glutamate-induced excitotoxicity, the most common pathological mechanism leading to neuronal death, may occur even with normal levels of glutamate if it coincides with a persistent enhancement of neuronal excitability. Neurons expressing nitric oxide (NO) synthase (NOS-I), which is upregulated in many human chronic neurodegenerative diseases, are highly susceptible to neurodegeneration. We hypothesized that chronic production of NO in damaged neurons may increase their intrinsic excitability via modulation of resting or "leak" K+ currents. Peripheral XIIth nerve injury in adult rats induced de novo NOS-I expression and an increased incidence of low-threshold motor units, the latter being prevented by chronic inhibition of the neuronal NO/cGMP pathway. Accordingly, sustained synthesis of NO maintained an enhanced basal activity in injured motoneurons that was slowly reverted (over the course of 2-3 h) by NOS-I inhibitors. In slice preparations, persistent, but not acute, activation of the NO/cGMP pathway evoked a robust augment in motoneuron excitability independent of synaptic activity. Furthermore, chronic activation of the NO/cGMP pathway fully suppressed TWIK-related acid-sensitive K+ (TASK) currents through a protein kinase G (PKG)-dependent mechanism. Finally, we found evidence for the involvement of this long-term mechanism in regulating membrane excitability of motoneurons, because their pH-sensitive currents were drastically reduced by nerve injury. This NO/cGMP/PKG-mediated modulation of TASK conductances might represent a new pathological mechanism that leads to hyperexcitability and sensitizes neurons to excitotoxic damage. It could explain why de novo expression of NOS-I and/or its overexpression makes them susceptible to neurodegeneration under pathological conditions.
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Affiliation(s)
- David González-Forero
- Área de Fisiología, Facultad de Medicina, Universidad de Cádiz, 11003 Cádiz, Spain, and
| | - Federico Portillo
- Área de Fisiología, Facultad de Medicina, Universidad de Cádiz, 11003 Cádiz, Spain, and
- Department of Physiology, School of Medical Sciences, University of Bristol, Bristol BS8 1TD, United Kingdom
| | - Laura Gómez
- Área de Fisiología, Facultad de Medicina, Universidad de Cádiz, 11003 Cádiz, Spain, and
| | - Fernando Montero
- Área de Fisiología, Facultad de Medicina, Universidad de Cádiz, 11003 Cádiz, Spain, and
| | - Sergey Kasparov
- Department of Physiology, School of Medical Sciences, University of Bristol, Bristol BS8 1TD, United Kingdom
| | - Bernardo Moreno-López
- Área de Fisiología, Facultad de Medicina, Universidad de Cádiz, 11003 Cádiz, Spain, and
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40
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Jones RJ, Jourd'heuil D, Salerno JC, Smith SME, Singer HA. iNOS regulation by calcium/calmodulin-dependent protein kinase II in vascular smooth muscle. Am J Physiol Heart Circ Physiol 2007; 292:H2634-42. [PMID: 17293490 DOI: 10.1152/ajpheart.01247.2006] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Nitric oxide synthase (NOS) expression is regulated transcriptionally in response to cytokine induction and posttranslationally by palmitoylation and trafficking into perinuclear aggresome-like structures. We investigated the effects of multifunctional calcium/calmodulin-dependent protein kinase II protein kinase (CaMKII) on inducible NOS (iNOS) trafficking in cultured rat aortic vascular smooth muscle cells (VSMCs). Immunofluorescence and confocal microscopy demonstrated colocalization of iNOS and CaMKIIdelta(2) with a perinuclear distribution and concentration in aggresome-like structures identified by colocalization with gamma-tubulin. Furthermore, CaMKIIdelta(2) coimmunoprecipitated with iNOS in a CaMKII activity-dependent manner. Addition of Ca(2+)-mobilizing stimuli expected to activate CaMKII; a purinergic agonist (UTP) or calcium ionophore (ionomycin) caused a general redistribution of iNOS from cytosolic to membrane and nuclear fractions. Similarly, adenoviral expression of a constitutively active CaMKIIdelta(2) mutant altered iNOS localization, shifting iNOS from the cytosolic fraction. Suppression of CaMKIIdelta(2) using an adenovirus expressing a short hairpin, small interfering RNA increased nuclear iNOS localization in resting cells but inhibited ionomycin-induced translocation of iNOS to the nucleus. Following addition of these chronic and acute CaMKII modulators, there were fewer aggresome-like structures containing iNOS. All of the treatments that chronically affected CaMKII activity or expression significantly inhibited iNOS-specific activity following cytokine induction. The results suggest that CaMKIIdelta(2) may be an important regulator of iNOS trafficking and activity in VSMCs.
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MESH Headings
- Animals
- Aorta, Thoracic/cytology
- Aorta, Thoracic/metabolism
- Benzylamines/pharmacology
- Calcium/metabolism
- Calcium-Calmodulin-Dependent Protein Kinase Type 2
- Calcium-Calmodulin-Dependent Protein Kinases/antagonists & inhibitors
- Calcium-Calmodulin-Dependent Protein Kinases/genetics
- Calcium-Calmodulin-Dependent Protein Kinases/metabolism
- Cell Membrane/enzymology
- Cell Nucleus/enzymology
- Cells, Cultured
- Cytokines/metabolism
- Cytoplasm/enzymology
- Enzyme Induction
- Interferon-gamma/metabolism
- Interleukin-1beta/metabolism
- Ionomycin/pharmacology
- Ionophores/pharmacology
- Male
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/enzymology
- Myocytes, Smooth Muscle/drug effects
- Myocytes, Smooth Muscle/enzymology
- Nitric Oxide Synthase Type II/biosynthesis
- Protein Kinase Inhibitors/pharmacology
- Protein Transport
- RNA, Small Interfering/genetics
- RNA, Small Interfering/metabolism
- Rats
- Rats, Sprague-Dawley
- Signal Transduction/drug effects
- Sulfonamides/pharmacology
- Tumor Necrosis Factor-alpha/metabolism
- Uridine Triphosphate/metabolism
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Affiliation(s)
- Rachel J Jones
- Center for Cardiovascular Sciences, Albany Medical College, 43 New Scotland Ave., Albany, NY 12208, USA
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Hardingham N, Fox K. The role of nitric oxide and GluR1 in presynaptic and postsynaptic components of neocortical potentiation. J Neurosci 2006; 26:7395-404. [PMID: 16837587 PMCID: PMC6674184 DOI: 10.1523/jneurosci.0652-06.2006] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
In this study, we investigated the mechanisms underlying synaptic plasticity at the layer IV to II/III pathway in barrel cortex of mice aged 6-13 weeks. This pathway is one of the likely candidates for expression of experience-dependent plasticity in the barrel cortex and may serve as a model for other IV to II/III synapses in the neocortex. We found that postsynaptic autocamtide-2-inhibitory peptide is sufficient to block long-term potentiation (LTP) (IC50 of 500 nm), implicating postsynaptic calcium/calmodulin-dependent kinase II in LTP induction. AMPA receptor subunit 1 (GluR1) knock-out mice also showed LTP in this pathway, but potentiation was predominantly presynaptic in origin as determined by paired-pulse analysis, coefficient of variation analysis, and quantal analysis, whereas wild types showed a mixed presynaptic and postsynaptic locus. Quantal analysis at this synapse was validated by measuring uniquantal events in the presence of strontium. The predominantly presynaptic LTP in the GluR1 knock-outs was blocked by postsynaptic antagonism of nitric oxide synthase (NOS), either with intracellular N-omega-nitro-L-arginine methyl ester or N-nitro-L-arginine, providing the first evidence for a retrograde transmitter role for NO at this synapse. Antagonism of NOS in wild types significantly reduced but did not eliminate LTP (group average reduction of 50%). The residual LTP formed a variable proportion of the total LTP in each cell and was found to be postsynaptic in origin. We found no evidence for silent synapses in this pathway at this age. Finally, application of NO via a donor induced potentiation in layer II/III cells and caused an increase in frequency but not amplitude of miniature EPSPs, again implicating NO in presynaptic plasticity.
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Cordelier P, Estève JP, Najib S, Moroder L, Vaysse N, Pradayrol L, Susini C, Buscail L. Regulation of Neuronal Nitric-oxide Synthase Activity by Somatostatin Analogs following SST5 Somatostatin Receptor Activation. J Biol Chem 2006; 281:19156-71. [PMID: 16690617 DOI: 10.1074/jbc.m602024200] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Somatostatin receptor SST5 is an inhibitory G protein-coupled receptor that exerts a strong cytostatic effect on various cell types. We reported previously that the SST5 anti-proliferative effect results in the inhibition of mitogen-induced increases in intracellular cGMP levels and MAPK activity. This study was conducted to define the early molecular events accountable for the SST5-mediated anti-proliferative effect. Here, we demonstrate that, in Chinese hamster ovary cells expressing SST5 (CHO/SST5 cells), somatostatin inhibited cell proliferation induced by nitric oxide donors and overexpression of the neuronal nitric-oxide synthase (nNOS) protein isoform. Accordingly, nNOS activity and dimerization were strongly inhibited following SST5 activation by the somatostatin analog RC-160. In CHO/SST5 cells, nNOS was dynamically recruited by the SST5 receptor and phosphorylated at tyrosyl residues following RC-160 treatment. RC-160 induced SST5-p60(src) kinase complex formation and subsequent p60(src) kinase activation. Coexpression of an inactive p60(src) kinase mutant with SST5 blocked RC-160-induced nNOS phosphorylation and inactivation and prevented the SST5-mediated anti-proliferative effect. In CHO/SST5 cells, p60(src) kinase associated with nNOS to induce its inactivation by phosphorylation at tyrosyl residues following RC-160 treatment. Using recombinant proteins, we demonstrated that such phosphorylation prevented nNOS homodimerization. Next, surface plasmon resonance and mutation analysis revealed that p60(src) directly associated with nNOS phosphorylated Tyr604. SST5-mediated inhibition of nNOS activity was demonstrated to be essential to the RC-160 anti-proliferative effect on pancreatic endocrine tumor-derived cells. We therefore identified nNOS as a new p60(src) kinase substrate essential for SST5-mediated anti-proliferative action.
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Affiliation(s)
- Pierre Cordelier
- INSERM U531, IFR31, Centre Hospitalier Universitaire Rangueil, 31432 Toulouse Cedex 4, France.
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Song T, Hatano N, Kume K, Sugimoto K, Yamaguchi F, Tokuda M, Watanabe Y. Inhibition of neuronal nitric-oxide synthase by phosphorylation at Threonine1296 in NG108-15 neuronal cells. FEBS Lett 2005; 579:5658-62. [PMID: 16214135 DOI: 10.1016/j.febslet.2005.09.037] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2005] [Revised: 09/09/2005] [Accepted: 09/09/2005] [Indexed: 11/20/2022]
Abstract
We demonstrate that neuronal nitric-oxide synthase (nNOS) is directly inhibited through the phosphorylation of Thr(1296) in NG108-15 neuronal cells. Treatment of NG108-15 cells expressing nNOS with calyculin A, an inhibitor of protein phosphatase 1 and 2A, revealed a dose-dependent inhibition of nNOS enzyme activity with concomitant phosphorylation of Thr(1296) residue. Cells expressing a phosphorylation-deficient mutant in which Thr(1296) was changed to Ala proved resistant to phosphorylation and suppression of NOS activity. Mimicking phosphorylation mutant of nNOS in which Thr(1296) is changed to Asp showed a significant decrease in nNOS enzyme activity, being competitive with NADPH, relative to the wild-type enzyme. These data suggest that phosphorylation of nNOS at Thr(1296) may involve the attenuation of nitric oxide production in neuronal cells through the decrease of NADPH-binding to the enzyme.
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Affiliation(s)
- Tao Song
- Department of Cell Physiology, Kagawa University, Faculty of Medicine, Miki-cho, Kida-gun, Japan
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45
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Xu L, Matsumura S, Mabuchi T, Takagi K, Abe T, Ito S. In situ measurement of neuronal nitric oxide synthase activity in the spinal cord by NADPH-diaphorase histochemistry. J Neurosci Methods 2005; 150:174-84. [PMID: 16085316 DOI: 10.1016/j.jneumeth.2005.06.017] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2005] [Revised: 06/08/2005] [Accepted: 06/17/2005] [Indexed: 11/17/2022]
Abstract
NADPH-diaphorase (NADPH-d) histochemistry has provided a simple method to stain neuronal nitric oxide synthase (nNOS)-containing neurons in the central nervous system. In the spinal cord, NO formation following activation of N-methyl-D-asparate (NMDA) receptors plays a crucial role in nociceptive processing. To investigate the molecular mechanisms, we attempted to evaluate nNOS activity in situ using isolated intact spinal cord preparation and NADPH-d histochemistry. NADPH-d activity in the superficial layer of the spinal cord increased gradually with ages from P10 to P30 and NMDA enhanced the NADPH-d staining in a time- and concentration-dependent manner. The NMDA-stimulated NADPH-d staining was inhibited by NMDA receptor antagonists, but not by non-NMDA and metabotropic glutamate receptor antagonists. The NADPH-d staining showed a pronounced stereospecificity for beta-NADPH and completely suppressed by dichlorophenolindophenol, an artificial electron acceptor. NMDA-evoked NO formation in the spinal cord was confirmed by the fluorescent NO indicator diaminofluorescein-FM (DAF-FM). These results demonstrate that NADPH-d activity in the superficial spinal cord is ascribed to nNOS activity and is dependent on NMDA. A combination of isolated intact spinal cord preparations and NADPH-d histochemistry may provide a unique system to elucidate biochemical and molecular mechanisms for nNOS activation in the spinal cord.
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Affiliation(s)
- Li Xu
- Department of Medical Chemistry, Kansai Medical University, Moriguchi, 570-8506 Osaka, Japan
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Dreyer J, Schleicher M, Tappe A, Schilling K, Kuner T, Kusumawidijaja G, Müller-Esterl W, Oess S, Kuner R. Nitric oxide synthase (NOS)-interacting protein interacts with neuronal NOS and regulates its distribution and activity. J Neurosci 2005; 24:10454-65. [PMID: 15548660 PMCID: PMC6730309 DOI: 10.1523/jneurosci.2265-04.2004] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Mechanisms governing the activity of neuronal nitric oxide synthase (nNOS), the major source of nitric oxide (NO) in the nervous system, are not completely understood. We report here a protein-protein interaction between nNOS and NOSIP (nitric oxide synthase-interacting protein) in rat brain in vivo. NOSIP and nNOS are concentrated in neuronal synapses and demonstrate significant colocalization in various regions of the central and peripheral nervous systems. NOSIP produces a significant reduction in nNOS activity in a neuroepithelioma cell line stably expressing nNOS. Furthermore, overexpression of NOSIP in cultured primary neurons reduces the availability of nNOS in terminal dendrites. These results thus suggest that the interaction between NOSIP and nNOS is functionally involved in endogenous mechanisms regulating NO synthesis. Furthermore, we found that the subcellular distribution and expression levels of NOSIP are dynamically regulated by neuronal activity in vitro as well as in vivo, suggesting that NOSIP may contribute to a mechanism via which neuronal activity regulates the synaptic availability and activity of nNOS.
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Affiliation(s)
- Jacqueline Dreyer
- Department of Molecular Pharmacology, Pharmacology Institute, University of Heidelberg, 69120 Heidelberg, Germany
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Waxman EA, Lynch DR. N-methyl-D-aspartate receptor subtypes: multiple roles in excitotoxicity and neurological disease. Neuroscientist 2005; 11:37-49. [PMID: 15632277 DOI: 10.1177/1073858404269012] [Citation(s) in RCA: 255] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
N-methyl-D-aspartate (NMDA) receptors are the major mediator of excitotoxicity. Although physiological activation of the NMDA receptor is necessary for cell survival, overactivation is a signal for cell death. Several pathways are activated through NMDA receptor stimulation, most of which can contribute to excitotoxicity. These include events leading to mitochondrial dysfunction, activation of calcium-dependent enzymes, and activation of mitogen-activated protein kinase pathways. Understanding the role of these mechanisms is important in developing agents that block excitotoxicity without inhibiting functions necessary for survival. NMDA receptor subtypes may be responsible for mediating separate pathways, and subtype-specific inhibition has shown promising results in some neurological models. This review examines the roles of NMDA receptor subtypes in excitotoxicity and neurological disorders.
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Affiliation(s)
- Elisa A Waxman
- Department of Pharmacology, University of Pennsylvania School of Medicine, Philadelphia, USA
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Jaffe H, Vinade L, Dosemeci A. Identification of novel phosphorylation sites on postsynaptic density proteins. Biochem Biophys Res Commun 2004; 321:210-8. [PMID: 15358237 DOI: 10.1016/j.bbrc.2004.06.122] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2004] [Indexed: 11/29/2022]
Abstract
Phosphorylation of the components of the postsynaptic density (PSD), a protein complex lining the postsynaptic membrane, may regulate synaptic structure and function. We carried out mass spectrometric analyses to identify phosphorylation sites on PSD proteins. Phosphopeptides were isolated from the total tryptic digest of a PSD fraction by immobilized metal affinity chromatography and analyzed by liquid chromatography and tandem mass spectrometry. The phosphorylated residues detected following in vitro phosphorylation in the presence of Ca2+/calmodulin included S-1058 on SynGAP and S-1662 and S-1668 on Shank3. Other phosphorylated residues were identified in control samples, presumably reflecting phosphorylation in the intact cell. These included the homologous residues, S-295 on PSD-95 and S-365 on PSD-93, located between the PDZ2 and PDZ3 domains of these proteins; and S-367 located on the actin-binding domain of beta-CaMKII. The sequence RXXSPV emerged as a common phosphorylation motif of three specialized PSD scaffolding proteins, PSD-95, PSD-93, and Shank3. Phosphorylated serine residues in several of the identified phosphorylation sites were followed by prolines, suggesting prominent involvement of proline directed kinases in the regulation of PSD components.
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Affiliation(s)
- H Jaffe
- Protein and Peptide Sequencing Facility, NIH/NINDS, Bethesda, MD, USA
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Huo L, Lee EKY, Leung PC, Wong AOL. Goldfish calmodulin: molecular cloning, tissue distribution, and regulation of transcript expression in goldfish pituitary cells. Endocrinology 2004; 145:5056-67. [PMID: 15297449 DOI: 10.1210/en.2004-0584] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Calmodulin (CaM) is a Ca(2+)-binding protein essential for biological functions mediated through Ca(2+)-dependent mechanisms. In the goldfish, CaM is involved in the signaling events mediating pituitary hormone secretion induced by hypothalamic factors. However, the structural identity of goldfish CaM has not been established, and the neuroendocrine mechanisms regulating CaM gene expression at the pituitary level are still unknown. Here we cloned the goldfish CaM and tested the hypothesis that pituitary expression of CaM transcripts can be the target of modulation by hypothalamic factors. Three goldfish CaM cDNAs, namely CaM-a, CaM-bS, and CaM-bL, were isolated by library screening. These cDNAs carry a 450-bp open reading frame encoding the same 149-amino acid CaM protein, the amino acid sequence of which is identical with that of mammals, birds, and amphibians and is highly homologous (>/=90%) to that in invertebrates. In goldfish pituitary cells, activation of cAMP- or PKC-dependent pathways increased CaM mRNA levels, whereas the opposite was true for induction of Ca(2+) entry. Basal levels of CaM mRNA was accentuated by GnRH and pituitary adenylate cyclase-activating polypeptide but suppressed by dopaminergic stimulation. Pharmacological studies using D1 and D2 analogs revealed that dopaminergic inhibition of CaM mRNA expression was mediated through pituitary D2 receptors. At the pituitary level, D2 activation was also effective in blocking GnRH- and pituitary adenylate cyclase-activating polypeptide-stimulated CaM mRNA expression. As a whole, the present study has confirmed that the molecular structure of CaM is highly conserved, and its mRNA expression at the pituitary level can be regulated by interactions among hypothalamic factors.
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Affiliation(s)
- Longfei Huo
- Department of Zoology, University of Hong Kong, Pokfulam Road, Hong Kong SAR, People's Republic of China
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Song T, Hatano N, Horii M, Tokumitsu H, Yamaguchi F, Tokuda M, Watanabe Y. Calcium/calmodulin-dependent protein kinase I inhibits neuronal nitric-oxide synthase activity through serine 741 phosphorylation. FEBS Lett 2004; 570:133-7. [PMID: 15251453 DOI: 10.1016/j.febslet.2004.05.083] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2004] [Revised: 04/30/2004] [Accepted: 05/20/2004] [Indexed: 11/22/2022]
Abstract
We demonstrate here that neuronal nitric-oxide synthase (nNOS) is phosphorylated and inhibited by a constitutively active form of Ca2+/calmodulin (CaM)-dependent protein kinase I (CaM-K I1-293). Substitution of Ser741 to Ala in nNOS blocked the phosphorylation and the inhibitory effect. Mimicking phosphorylation at Ser741 by Ser to Asp mutation resulted in decreased binding of and activation by CaM, since the mutation was within the CaM-binding domain. CaM-K I1-293 gave phosphorylation of nNOS at Ser741 in transfected cells, resulting in 60-70% inhibition of nNOS activity. Wild-type CaM-K I also did phosphorylate nNOS at Ser741 in transfected cells, but either CaM-K II or CaM-K IV did not. These results raise the possibility of a novel cross-talk between nNOS and CaM-K I through the phosphorylation of Ser741 on nNOS.
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Affiliation(s)
- Tao Song
- Department of Cell Physiology, Kagawa University, Faculty of Medicine, 1750-1 Ikenobe, Miki-cho, Kida-gun, Kagawa 761-0793, Japan
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