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Targeting NMDA Receptors in Emotional Disorders: Their Role in Neuroprotection. Brain Sci 2022; 12:brainsci12101329. [PMID: 36291261 PMCID: PMC9599159 DOI: 10.3390/brainsci12101329] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Revised: 09/28/2022] [Accepted: 09/28/2022] [Indexed: 12/03/2022] Open
Abstract
Excitatory glutamatergic neurotransmission mediated through N-methyl-D-Aspartate (NMDA) receptors (NMDARs) is essential for synaptic plasticity and neuronal survival. While under pathological states, abnormal NMDAR activation is involved in the occurrence and development of psychiatric disorders, which suggests a directional modulation of NMDAR activity that contributes to the remission and treatment of psychiatric disorders. This review thus focuses on the involvement of NMDARs in the pathophysiological processes of psychiatric mood disorders and analyzes the neuroprotective mechanisms of NMDARs. Firstly, we introduce NMDAR-mediated neural signaling pathways in brain function and mood regulation as well as the pathophysiological mechanisms of NMDARs in emotion-related mental disorders such as anxiety and depression. Then, we provide an in-depth summary of current NMDAR modulators that have the potential to be developed into clinical drugs and their pharmacological research achievements in the treatment of anxiety and depression. Based on these findings, drug-targeting for NMDARs might open up novel territory for the development of therapeutic agents for refractory anxiety and depression.
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Kurnik-Łucka M, Panula P, Bugajski A, Gil K. Salsolinol: an Unintelligible and Double-Faced Molecule-Lessons Learned from In Vivo and In Vitro Experiments. Neurotox Res 2017; 33:485-514. [PMID: 29063289 PMCID: PMC5766726 DOI: 10.1007/s12640-017-9818-6] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Revised: 08/19/2017] [Accepted: 09/08/2017] [Indexed: 12/29/2022]
Abstract
Salsolinol (1-methyl-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline) is a tetrahydroisoquinoline derivative whose presence in humans was first detected in the urine of Parkinsonian patients on l-DOPA (l-dihydroxyphenylalanine) medication. Thus far, multiple hypotheses regarding its physiological/pathophysiological roles have been proposed, especially related to Parkinson’s disease or alcohol addiction. The aim of this review was to outline studies related to salsolinol, with special focus on in vivo and in vitro experimental models. To begin with, the chemical structure of salsolinol together with its biochemical implications and the role in neurotransmission are discussed. Numerous experimental studies are summarized in tables and the most relevant ones are stressed. Finally, the ability of salsolinol to cross the blood–brain barrier and its possible double-faced neurobiological potential are reviewed.
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Affiliation(s)
- Magdalena Kurnik-Łucka
- Department of Pathophysiology, Jagiellonian University Medical College, Czysta 18, 30-121, Krakow, Poland.
| | - Pertti Panula
- Department of Anatomy and Neuroscience Centre, University of Helsinki, Helsinki, Finland
| | - Andrzej Bugajski
- Department of Pathophysiology, Jagiellonian University Medical College, Czysta 18, 30-121, Krakow, Poland
| | - Krzysztof Gil
- Department of Pathophysiology, Jagiellonian University Medical College, Czysta 18, 30-121, Krakow, Poland
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Chwastek J, Jantas D, Lasoń W. The ATM kinase inhibitor KU-55933 provides neuroprotection against hydrogen peroxide-induced cell damage via a γH2AX/p-p53/caspase-3-independent mechanism: Inhibition of calpain and cathepsin D. Int J Biochem Cell Biol 2017; 87:38-53. [PMID: 28341201 DOI: 10.1016/j.biocel.2017.03.015] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Revised: 02/20/2017] [Accepted: 03/20/2017] [Indexed: 02/07/2023]
Abstract
The role of the kinase ataxia-telangiectasia mutated (ATM), a well-known protein engaged in DNA damage repair, in the regulation of neuronal responses to oxidative stress remains unexplored. Thus, the neuroprotective efficacy of KU-55933, a potent inhibitor of ATM, against cell damage evoked by oxidative stress (hydrogen peroxide, H2O2) has been studied in human neuroblastoma SH-SY5Y cells and compared with the efficacy of this agent in models of doxorubicin (Dox)- and staurosporine (St)-evoked cell death. KU-55933 inhibited the cell death induced by H2O2 or Dox but not by St in undifferentiated (UN-) and retinoic acid-differentiated (RA)-SH-SY5Y cells, with a more pronounced effect in the latter cell phenotype. Furthermore, this ATM inhibitor attenuated the Dox- but not H2O2-induced caspase-3 activity in both UN- and RA-SH-SY5Y cells. Although KU-55933 inhibited the H2O2- and Dox-induced activation of ATM, it attenuated the toxin-induced phosphorylation of the proteins H2AX and p53 only in the latter model of cell damage. Moreover, the ATM inhibitor prevented the H2O2-evoked increases in calpain and cathepsin D activity and attenuated cell damage to a similar degree as inhibitors of calpain (MDL28170) and cathepsin D (pepstatin A). Finally, we confirmed the neuroprotective potential of KU-55933 against the H2O2- and Dox-evoked cell damage in primary mouse cerebellar granule cells and in the mouse hippocampal HT-22 cell line. Altogether, our results extend the neuroprotective portfolio of KU-55933 to a model of oxidative stress, with this effect not involving inhibition of the γH2AX/p-p53/caspase-3 pathway and instead associated with the attenuation of calpain and cathepsin D activity.
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Affiliation(s)
- Jakub Chwastek
- Institute of Pharmacology, Polish Academy of Sciences, Department of Experimental Neuroendocrinology, Smętna Street 12, 31-343 Kraków, Poland
| | - Danuta Jantas
- Institute of Pharmacology, Polish Academy of Sciences, Department of Experimental Neuroendocrinology, Smętna Street 12, 31-343 Kraków, Poland.
| | - Władysław Lasoń
- Institute of Pharmacology, Polish Academy of Sciences, Department of Experimental Neuroendocrinology, Smętna Street 12, 31-343 Kraków, Poland
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The neuroprotective effects of orthosteric agonists of group II and III mGluRs in primary neuronal cell cultures are dependent on developmental stage. Neuropharmacology 2016; 111:195-211. [PMID: 27600687 DOI: 10.1016/j.neuropharm.2016.09.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Revised: 08/12/2016] [Accepted: 09/02/2016] [Indexed: 11/22/2022]
Abstract
Activation of metabotropic glutamate receptors (mGluRs) modulates neuronal excitability. Here, we evaluated the neuroprotective potential of four structurally diverse activators of group II and III mGluRs: an orthosteric agonist of group II (LY354740), an orthosteric agonist of group III (ACPT-I), an allosteric agonist of mGluR7 (AMN082) and a positive allosteric modulator (PAM) of mGluR4 (VU0361737). Neurotoxicity was induced by the pro-apoptotic agents: staurosporine (St) and doxorubicin (Dox) or the excitotoxic factor glutamate (Glu). The effects were analyzed in primary hippocampal (HIP) and cerebellar granule cell (CGC) cultures at two developmental stages, at 7 and 12 days in vitro (DIV). The data reveal a general neuroprotective effect of group II and III mGluR activators against the St- and Glu- but not Dox-induced cell damage. We found that neuroprotective effects of group II and III mGluR orthosteric agonists (LY354740 and ACPT-I) were higher at 12 DIV when compared to 7 DIV cells. In contrast, the efficiency of allosteric mGluR agents (AMN082 and VU0361737) did not differ between 7 and 12 DIV in both, St and Glu models of neuronal cell damage. Interestingly, the protective effects of activators of group II and III mGluRs were blocked by relevant antagonists only against Glu-induced neurotoxicity. Moreover, the observed neuroprotective action of group II and III mGluR activators in the St model was associated with a decreased number of PI-positive cells and no alterations in the caspase-3 activity. Finally, we showed that MAPK/ERK pathway activation was potentially involved in the mechanism of ACPT-I- and AMN082-induced neuroprotection against the St-evoked cellular damage. Our comparative study demonstrated the developmental stage-dependent neuroprotective effect of orthosteric group II and III mGluR agonists. In comparison to allosteric modulators, orthosteric compounds may provide more specific tools for suppression of neuronal cell loss associated with various chronic neurodegenerative conditions. Our results also suggest that the inhibition of intracellular pathways mediating necrotic, rather than apoptotic cascades, may be involved in neuroprotective effects of activators of group II and III mGluRs.
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Wu ZM, Ding Y, Jia HX, Li L. Different effects of isolation-rearing and neonatal MK-801 treatment on attentional modulations of prepulse inhibition of startle in rats. Psychopharmacology (Berl) 2016; 233:3089-102. [PMID: 27370017 DOI: 10.1007/s00213-016-4351-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Accepted: 06/02/2016] [Indexed: 01/04/2023]
Abstract
RATIONAL Prepulse inhibition (PPI) is suppression of the startle reflex by a weaker sensory stimulus (prepulse) preceding the startling stimulus. In people with schizophrenia, impairment of attentional modulation of PPI, but not impairment of baseline PPI, is correlated with symptom severity. In rats, both fear conditioning of prepulse and perceptually spatial separation between the conditioned prepulse and a noise masker enhance PPI (the paradigms of attentional modulation of PPI). OBJECTIVES As a neurodevelopmental model of schizophrenia, isolation rearing impairs both baseline PPI and attentional modulations of PPI in rats. This study examined in Sprague-Dawley male rats whether neonatally blocking N-methyl-D-aspartate (NMDA) receptors specifically affects attentional modulations of PPI during adulthood. RESULTS Both socially reared rats with neonatal exposure to the NMDA receptor antagonist MK-801 and isolation-reared rats exhibited augmented startle responses, but only isolation rearing impaired baseline PPI. Fear conditioning of the prepulse enhanced PPI in socially reared rats, but MK-801-treated rats lost the prepulse feature specificity. Perceptually spatial separation between the conditioned prepulse and a noise masker further enhanced PPI only in normally reared rats. Clozapine administration during adulthood generally weakened startle, enhanced baseline PPI in neonatally interrupted rats, and restored the fear conditioning-induced PPI enhancement in isolation-reared rats with a loss of the prepulse feature specificity. Clozapine administration also abolished both the perceptual separation-induced PPI enhancement in normally reared rats and the fear conditioning-induced PPI enhancement in MK-801-treated rats. CONCLUSIONS Isolation rearing impairs both baseline PPI and attentional modulations of PPI, but neonatally disrupting NMDA receptor-mediated transmissions specifically impair attentional modulations of PPI. Clozapine has limited alleviating effects.
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Affiliation(s)
- Zhe-Meng Wu
- Department of Psychology and Beijing Key Laboratory of Behavior and Mental Health, Speech and Hearing Research Center, Key Laboratory on Machine Perception (Ministry of Education), Peking University, Beijing, 100080, China
| | - Yu Ding
- Department of Psychology and Beijing Key Laboratory of Behavior and Mental Health, Speech and Hearing Research Center, Key Laboratory on Machine Perception (Ministry of Education), Peking University, Beijing, 100080, China
| | - Hong-Xiao Jia
- Beijing Key Laboratory for Mental Disorders, Center of Schizophrenia,Beijing Anding Hospital, Capital Medical University, Beijing, 100088, China. .,Beijing Institute for Brain Disorders, Beijing, China.
| | - Liang Li
- Department of Psychology and Beijing Key Laboratory of Behavior and Mental Health, Speech and Hearing Research Center, Key Laboratory on Machine Perception (Ministry of Education), Peking University, Beijing, 100080, China. .,Beijing Institute for Brain Disorders, Beijing, China.
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Sulforaphane Prevents Methylmercury-Induced Oxidative Damage and Excitotoxicity Through Activation of the Nrf2-ARE Pathway. Mol Neurobiol 2016; 54:375-391. [PMID: 26742517 DOI: 10.1007/s12035-015-9643-y] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Accepted: 12/16/2015] [Indexed: 12/29/2022]
Abstract
Methylmercury (MeHg) is a prominent environmental neurotoxicant, which induces oxidative damage and an indirect excitotoxicity caused by altered glutamate (Glu) metabolism. However, the interaction between oxidative damage and excitotoxicity in MeHg-exposed rats has not been fully recognized. Here, we explored the interaction between oxidative damage and excitotoxicity and evaluated the preventive effects of sulforaphane (SFN) on MeHg-induced neurotoxicity in rat cerebral cortex. Seventy-two rats were randomly assigned to four groups: control group, MeHg-treated groups (4 and 12 μmol/kg), and SFN pretreatment group. After treatment (28 days), the rats were killed and the cerebral cortex was analyzed. Then, Hg, glutathione (GSH), malondialdehyde (MDA), protein sulfhydryl, protein carbonyl, 8-hydroxy-2-deoxyguanosine (8-OHdG), and the levels of reactive oxygen species (ROS) and apoptosis were examined. Glu and glutamine (Gln) levels, glutamine synthetase (GS), phosphate-activated glutaminase (PAG), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), Na+-K+-ATPase and Ca2+-ATPase activities, intracellular Ca2+ levels, and the mRNA and protein expressions of Nrf2, Nrf2-regulated gene products, and N-methyl-D-aspartate receptors (NMDARs) were investigated in rat cerebral cortex. In our study, MeHg exposure not only induced Hg accumulation, apoptosis, ROS formation, GSH depletion, inhibition of antioxidant enzyme activities, and activation of Nrf2-ARE pathway signaling but also caused lipid, protein, and DNA peroxidative damage in a dose-dependent manner in rat cerebral cortex. Moreover, MeHg treatment significantly altered Gln/Glu cycling and NMDAR expression and resulted in calcium overloading. Furthermore, the present study also indicated that SFN pretreatment significantly reinforced the activation of the Nrf2-ARE pathway, which could prevent the toxic effects of MeHg exposure. Collectively, MeHg initiates multiple additive or synergistic disruptive mechanisms that lead to oxidative damage and excitotoxicity in rat cerebral cortex; pretreatment with SFN might prevent the MeHg-induced neurotoxicity by reinforcing the activation of the Nrf2-ARE pathway and then downregulating the interaction between oxidative damage and excitotoxicity pathways.
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Marine compound xyloketal B reduces neonatal hypoxic-ischemic brain injury. Mar Drugs 2014; 13:29-47. [PMID: 25546517 PMCID: PMC4306923 DOI: 10.3390/md13010029] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Accepted: 12/11/2014] [Indexed: 12/21/2022] Open
Abstract
Neonatal hypoxic-ischemic encephalopathy causes neurodegeneration and brain injury, leading to sensorimotor dysfunction. Xyloketal B is a novel marine compound isolated from a mangrove fungus Xylaria species (no. 2508) with unique antioxidant effects. In this study, we investigated the effects and mechanism of xyloketal B on oxygen-glucose deprivation-induced neuronal cell death in mouse primary cortical culture and on hypoxic-ischemic brain injury in neonatal mice in vivo. We found that xyloketal B reduced anoxia-induced neuronal cell death in vitro, as well as infarct volume in neonatal hypoxic-ischemic brain injury model in vivo. Furthermore, xyloketal B improved functional behavioral recovery of the animals following hypoxic-ischemic insult. In addition, xyloketal B significantly decreased calcium entry, reduced the number of TUNEL-positive cells, reduced the levels of cleaved caspase-3 and Bax proteins, and increased the level of Bcl-2 protein after the hypoxic-ischemic injury. Our findings indicate that xyloketal B is effective in models of hypoxia-ischemia and thus has potential as a treatment for hypoxic-ischemic brain injury.
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Canu N, Ciotti MT, Pollegioni L. Serine racemase: a key player in apoptosis and necrosis. Front Synaptic Neurosci 2014; 6:9. [PMID: 24795622 PMCID: PMC4000995 DOI: 10.3389/fnsyn.2014.00009] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Accepted: 03/28/2014] [Indexed: 12/14/2022] Open
Abstract
A fine balance between cell survival and cell death is required to sculpt the nervous system during development. However, an excess of cell death can occur following trauma, exposure to neurotoxins or alcohol, and some developmental and neurodegenerative diseases, such as Alzheimer's disease (AD). N-Methyl-D-aspartate receptors (NMDARs) support synaptic plasticity and survival of many neuronal populations whereas inappropriate activation may promote various forms of cell death, apoptosis, and necrosis representing the two extremes of a continuum of cell death processes both “in vitro” and “in vivo.” Hence, by identifying the switches controlling pro-survival vs. apoptosis and apoptosis vs. pro-excitotoxic outcome of NMDAR stimulation, NMDAR modulators could be developed that selectively block the cell death enhancing pro-survival signaling or synaptic plasticity mediated by NMDAR. Among these modulators, a role is emerging for the enzyme serine racemase (SR) that synthesizes D-serine, a key co-agonist with glutamate at NMDAR. This review summarizes the experimental evidence from “in vitro” neuronal cultures—with special emphasis on cerebellar granule neurons (CGNs)—and “in vivo” models of neurodegeneration, where the dual role of the SR/D-serine pathway as a master regulator of apoptosis and the apoptosis-necrosis shift will be discussed.
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Affiliation(s)
- Nadia Canu
- Dipartimento di Medicina dei Sistemi, Università degli Studi di Roma Roma, Italy ; Istituto di Biologia Cellulare e Neurobiologia, Consiglio Nazionale delle Ricerche Roma, Italy
| | - Maria Teresa Ciotti
- Istituto di Biologia Cellulare e Neurobiologia, Consiglio Nazionale delle Ricerche Roma, Italy
| | - Loredano Pollegioni
- Dipartimento di Biotecnologie e Scienze della Vita, Università degli Studi dell'Insubria Varese, Italy ; Centro Interuniversitario di Ricerca in Biotecnologie Proteiche "The Protein Factory," Politecnico di Milano, ICRM-CNR Milano and Università degli studi dell'Insubria Milano, Italy
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Liu W, Xu Z, Deng Y, Xu B, Yang H, Wei Y, Feng S. Excitotoxicity and oxidative damages induced by methylmercury in rat cerebral cortex and the protective effects of tea polyphenols. ENVIRONMENTAL TOXICOLOGY 2014; 29:269-283. [PMID: 22223486 DOI: 10.1002/tox.21755] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2011] [Revised: 11/28/2011] [Accepted: 12/03/2011] [Indexed: 05/31/2023]
Abstract
Methylmercury (MeHg) is a highly neurotoxic environmental pollutant that has a high appetency to the central nervous system. The underlying mechanisms of MeHg-induced neurotoxicity have not been elucidated clearly until now. Therefore, to explore the mechanisms contribute to MeHg-induced neurotoxicity, rats were exposed to different dosage of methylmercury chloride (CH3 ClHg) (0, 4, and 12 μmol kg(-1)) for 4 weeks to evaluate the neurotoxic effects of MeHg. In addition, considering the antioxidative properties of tea polyphenols (TP), 1 mmol kg(-1) TP was pretreated to observe the possible protective effects on MeHg-induced neurotoxicity. Then Hg, glutamate (Glu) and glutamine (Gln) levels, glutamine synthetase (GS), phosphate-activated glutaminase (PAG), Na(+)-K(+)-ATPase, and Ca(2+)-ATPase activities, intracellular Ca(2+) level were examined, glutathione (GSH), malondialdehyde (MDA), protein sulfhydryl, carbonyl, 8-hydroxy-2-deoxyguanosine (8-OHdG), and reactive oxygen species (ROS) levels, N-methyl-D-aspartate receptors (NMDARs) mRNA and protein expressions, apoptosis level and morphological changes in the cerebral cortex were also investigated. Study results showed that compared with those in control, exposure to CH3 ClHg resulted in excitotoxicity in a concentration-dependent manner, which was shown by the Glu-Gln cycle disruption and intracellular Ca(2+) homeostasis disturbance. On the other hand, CH3 ClHg exposure resulted in oxidative damages of brain, which were supported by the significant changes on GSH, MDA, sulfhydryl, carbonyl, 8-OHdG, and ROS levels. Moreover, apoptosis rate increased obviously and many morphological changes were found after CH3 ClHg exposure. Furthermore, this research indicated that TP pretreatment significantly mitigated the toxic effects of MeHg. In conclusion, findings from this study indicated that exposure to MeHg could induce excitotoxicity and oxidative damage in cerebral cortex while TP might antagonize the MeHg-induced neurotoxicity.
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Affiliation(s)
- Wei Liu
- Department of Environmental Health, School of Public Health, China Medical University, North 2nd Road 92, Heping Ward, Shenyang 110001, Liaoning Province, People's Republic of China
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Bahrami F, Hashemi M, Khalili F, Hashemi J, Asgari A. Stimulation of CB1 Cannabinoid and NMDA Receptors Increases Neuroprotective Effect against Diazinon-Induced Neurotoxicity. NEUROPHYSIOLOGY+ 2013. [DOI: 10.1007/s11062-013-9390-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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Gu Q, Zhai L, Feng X, Chen J, Miao Z, Ren L, Qian X, Yu J, Li Y, Xu X, Liu CF. Apelin-36, a potent peptide, protects against ischemic brain injury by activating the PI3K/Akt pathway. Neurochem Int 2013; 63:535-40. [DOI: 10.1016/j.neuint.2013.09.017] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2013] [Revised: 08/17/2013] [Accepted: 09/22/2013] [Indexed: 01/08/2023]
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Liu W, Xu Z, Deng Y, Xu B, Wei Y, Yang T. Protective effects of memantine against methylmercury-induced glutamate dyshomeostasis and oxidative stress in rat cerebral cortex. Neurotox Res 2013; 24:320-37. [PMID: 23504438 DOI: 10.1007/s12640-013-9386-3] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2012] [Revised: 02/25/2013] [Accepted: 03/05/2013] [Indexed: 12/26/2022]
Abstract
Methylmercury (MeHg) is one of the ubiquitous environmental toxicant that leads to long-lasting neurological deficits in animals and humans. The identification of the underlying mechanisms has been a main focus of research in the neurotoxicology field. Glutamate (Glu) dyshomeostasis and oxidative stress have been identified as two critical mechanisms mediating MeHg-induced neurotoxicity. However, little has been known of the interaction between these two mechanisms that play in MeHg poisoning in vivo. We, therefore, developed a rat model of MeHg subchronic poisoning to evaluate its neurotoxic effects and investigated the neuroprotective role of memantine, a low-affinity, noncompetitive N-methyl-D-aspartate receptors (NMDARs) antagonist, against MeHg-induced neurotoxicity. Ninety rats were randomly divided into five groups: control, memantine control, MeHg-treated (4 and 12 μmol/kg), and memantine pretreated. Administration of 12 μmol/kg MeHg for 4 weeks significantly elevated total Hg levels, disrupted Glu metabolism, overexcited NMDARs, and led to intracellular calcium overload, which might be critical to excessive reactive oxygen species (ROS) formation in cerebral cortex. Meanwhile, MeHg administration reduced non-enzymatic (non-protein sulfhydryl, NPSH) and enzymatic (superoxide dismutase, SOD and glutathione peroxidase, GSH-Px) antioxidants; caused lipid, protein, and DNA oxidative damage; and enhanced neurocyte apoptosis in cerebral cortex. Moreover, glutamate/aspartate transporter (GLAST) and glutamate transporter-1 (GLT-1) appear to be inhibited by MeHg exposure. Pretreatment with memantine at a dose of 5 μmol/kg significantly prevented MeHg-induced alterations of Glu metabolism and oxidative stress, alleviated neurocyte apoptosis, and pathological injury. In conclusion, the results suggested that Glu dyshomeostasis and oxidative stress resulting from MeHg exposure contributed to neuronal injury. Memantine possesses the ability to attenuate MeHg-induced neurotoxicity through mechanisms involving its NMDARs-binding properties and indirect antioxidation.
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Affiliation(s)
- Wei Liu
- Department of Environmental Health, School of Public Health, China Medical University, Shenyang, 110001, Liaoning, People's Republic of China
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Lee YJ, Lee HG, Yang JH. Perfluorooctane sulfonate-induced apoptosis of cerebellar granule cells is mediated by ERK 1/2 pathway. CHEMOSPHERE 2013; 90:1597-1602. [PMID: 22990021 DOI: 10.1016/j.chemosphere.2012.08.033] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2012] [Revised: 08/12/2012] [Accepted: 08/20/2012] [Indexed: 06/01/2023]
Abstract
Perfluorooctane sulfonate (PFOS), a ubiquitous environmental pollutant, is considered as a neurotoxicant to mammalian species. However, the underlying mechanism of its neurotoxicity is largely unknown. In the present study, we examined roles of mitogen-activated protein kinases (MAPKs) in PFOS-induced apoptosis of neuronal cells to elucidate the molecular mechanism. Cerebellar granule cells were isolated from 7-d old rats and maintained in culture for additional 7 d. Cells were exposed to PFOS and caspase-3 activity and nuclear morphology were evaluated by enzyme activity assay and Hoechst 33342 staining, respectively, to determine its effects on apoptosis. The treatment with PFOS resulted in caspase-3 activation and nuclear condensation and fragmentation. PFOS exposure selectively increased activation of ERK that remained above control over 6 h. The inhibitor of ERK pathway, PD98059, substantially blocked caspase-3 activation induced by PFOS, whereas inhibitors of JNK and p38 MAPK, SP600125 and SB203580, respectively, had no effect. PKC inhibitors, bisindolylmaleimide I and Gö6976, dampened caspase-3 activity and ERK activation induced by PFOS. Collectively, it is suggested that PKC and ERK play proapoptotic roles in PFOS-induced apoptosis of cerebellar granule cells and PKC act as an upstream regulator of ERK activation.
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Affiliation(s)
- Youn Ju Lee
- Department of Pharmacology and Toxicology, School of Medicine, Catholic University of Daegu, Daegu, Republic of Korea
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Zhang X, Peng X, Fang M, Zhou C, Zhao F, Zhang Y, Xu Y, Zhu Q, Luo J, Chen G, Wang X. Up-regulation of apelin in brain tissue of patients with epilepsy and an epileptic rat model. Peptides 2011; 32:1793-9. [PMID: 21864607 DOI: 10.1016/j.peptides.2011.08.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2011] [Revised: 08/08/2011] [Accepted: 08/08/2011] [Indexed: 11/12/2022]
Abstract
Prolonged epileptic seizures or SE can cause neuronal cell death. However, the exact role of neuroprotectant against brain injury during epileptic seizure needs to be further elucidated. The aim of this study was to investigate the expression of the apelin, a novel neuroprotective peptide, in brain tissues of the patients with temporal lobe epilepsy (TLE) and experimental rats using immunohistochemistry, immunofluorescence and Western blotting analysis and to discuss the possible role of apelin in TLE. Thirty temporal neocortical tissue samples from the patients with drug-refractory TLE underwent surgical therapy and nine histologically normal temporal lobes tissues as controls were used in our study. Fifty-six Sprague-Dawley rats were randomly divided into seven groups, including one control group and six groups with epilepsy induced by lithium-pilocarpine. Hippocampus and adjacent cortex were taken from the controls and epileptic rats at 1, 3, 7, 14, 30, and 60 days after onset of seizures. Apelin was mainly expressed in the neurons of TLE patients and controls, and was significantly increased in TLE patients compared with the controls. Apelin was also expressed in the neurons of experimental and control rats, it was gradually increased in the experimental rat post-seizure and reached a stable high level in chronic epileptic phase. Our results demonstrated that the increased expression of apelin in the brain may be involved in human TLE.
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Affiliation(s)
- Xiaogang Zhang
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Neurology, 1st Youyi Road, Chongqing 400016, China
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Navon H, Bromberg Y, Sperling O, Shani E. Neuroprotection by NMDA Preconditioning Against Glutamate Cytotoxicity is Mediated Through Activation of ERK 1/2, Inactivation of JNK, and by Prevention of Glutamate-Induced CREB Inactivation. J Mol Neurosci 2011; 46:100-8. [DOI: 10.1007/s12031-011-9532-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2011] [Accepted: 04/25/2011] [Indexed: 02/05/2023]
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Neuhaus W, Freidl M, Szkokan P, Berger M, Wirth M, Winkler J, Gabor F, Pifl C, Noe CR. Effects of NMDA receptor modulators on a blood-brain barrier in vitro model. Brain Res 2011; 1394:49-61. [PMID: 21549356 DOI: 10.1016/j.brainres.2011.04.003] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2010] [Revised: 03/21/2011] [Accepted: 04/01/2011] [Indexed: 01/29/2023]
Abstract
Changes of the functionality of the blood-brain barrier (BBB) have been reported in the context of several brain related diseases such as multiple sclerosis, epilepsy, Alzheimer's disease and stroke. Several publications indicated the presence and functionality of the NMDA receptor (NMDAR) at the brain endothelium and a possible involvement of the NMDAR in the above-mentioned diseases. Recently, it was shown that the application of the NMDAR antagonist MK801 can block several adverse effects at the BBB in vitro, but also that MK801 can significantly change the proteome of brain endothelial cells without simultaneous stimulation of NMDAR by glutamate. Based on these reports we investigated if NMDAR antagonists MK801 and D-APV can affect the intracellular calcium level (Ca²⁺i) of an in vitro BBB model based on human cell line ECV304 on their own and compared these results to effects mediated by NMDAR agonists glutamate and NMDA. Treatment of ECV304 cells for 30 min with glutamate resulted in no significant change of Ca²⁺i. On the contrary, application of NMDA and NMDAR antagonists D-APV and MK801 led to a significant and concentration dependent decrease of Ca²⁺i. Further studies revealed that glutamate was able to decrease the transendothelial electrical resistance (TEER) of the BBB in vitro model, whereas NMDA and D-APV were able to increase TEER. Analysis of the protein expression levels of tight junctional molecules ZO-1 and occludin showed a complex regulation after application of NMDAR modulators. In summary, it was shown that NMDAR antagonists can alter BBB key properties in vitro on their own. Moreover, although qPCR results confirmed the presence of NMDA receptor subunits NR1, NR2A, NR2B and NR2C, membrane binding studies failed to prove the typical plasma membrane localization and functionality in human BBB cell line ECV304.
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Affiliation(s)
- Winfried Neuhaus
- Department of Anaesthesia and Critical Care, University Hospital Würzburg, Oberdürrbacherstrasse 6, 97080 Würzburg, Germany
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Blancas S, Moran J. Role for apoptosis-inducing factor in the physiological death of cerebellar neurons. Neurochem Int 2011; 58:934-42. [PMID: 21447364 DOI: 10.1016/j.neuint.2011.03.017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2010] [Revised: 03/09/2011] [Accepted: 03/18/2011] [Indexed: 11/29/2022]
Abstract
Apoptosis-inducing factor (AIF) is implicated in caspase-independent apoptotic-like death. AIF released from mitochondria translocates to the nucleus, where it mediates some apoptotic events such as chromatin condensation and DNA degradation. Here, the role of AIF in the neuronal death was studied under physiological conditions. When we analyzed the cellular localization of AIF during cerebellar development, we found a significant increase in the number of neurons with nuclear AIF localization in an age-dependent manner. On the other hand, cerebellar granule neurons (CGN) chronically cultured in low concentration of potassium (5 mM; K5) die with apoptotic-like characteristics after five days. In the present study we found that K5 induces a caspase-dependent apoptotic-like death of CGN as well as a late nuclear translocation of AIF. When CGN death induced by K5 was carried out in the presence of a general inhibitor of caspases, there was a slight decrement of cell death, but neurons eventually died by showing apoptotic-like features such as phosphatidylserine translocation and nuclear condensation. Besides, there was a significant increment of nuclear AIF translocation. These findings support the idea that AIF could be involved in apoptotic-like death of CGN and that it could be an alternative mechanism of neuronal death during cerebellar development.
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Affiliation(s)
- Sugela Blancas
- Neuroscience Division, Institute of Cell Physiology, National Autonomous University of Mexico, Mexico City, Mexico
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Cao Q, Qian M, Wang XF, Wang B, Wu HW, Zhu XJ, Wang YW, Guo J. Negative Feedback Regulation of Raf/MEK/ERK Cascade After Sublethal Cerebral Ischemia in the Rat Hippocampus. Neurochem Res 2010; 36:153-62. [DOI: 10.1007/s11064-010-0285-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/28/2010] [Indexed: 10/19/2022]
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Zeng XJ, Yu SP, Zhang L, Wei L. Neuroprotective effect of the endogenous neural peptide apelin in cultured mouse cortical neurons. Exp Cell Res 2010; 316:1773-83. [PMID: 20152832 DOI: 10.1016/j.yexcr.2010.02.005] [Citation(s) in RCA: 125] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2009] [Revised: 02/03/2010] [Accepted: 02/03/2010] [Indexed: 12/30/2022]
Abstract
The adipocytokine apelin and its G protein-coupled APJ receptor were initially isolated from a bovine stomach and have been detected in the brain and cardiovascular system. Recent studies suggest that apelin can protect cardiomyocytes from ischemic injury. Here, we investigated the effect of apelin on apoptosis in mouse primary cultures of cortical neurons. Exposure of the cortical cultures to a serum-free medium for 24 h induced nuclear fragmentation and apoptotic death; apelin-13 (1.0-5.0 nM) markedly prevented the neuronal apoptosis. Apelin neuroprotective effects were mediated by multiple mechanisms. Apelin-13 reduced serum deprivation (SD)-induced ROS generation, mitochondria depolarization, cytochrome c release and activation of caspase-3. Apelin-13 prevented SD-induced changes in phosphorylation status of Akt and ERK1/2. In addition, apelin-13 attenuated NMDA-induced intracellular Ca(2+) accumulation. These results indicate that apelin is an endogenous neuroprotective adipocytokine that may block apoptosis and excitotoxic death via cellular and molecular mechanisms. It is suggested that apelins may be further explored as a potential neuroprotective reagent for ischemia-induced brain damage.
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Affiliation(s)
- Xiang Jun Zeng
- Department of Pathophysiology, Capital Medical University, Beijing 100069, China
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de Rivero Vaccari JP, Marcillo A, Nonner D, Dietrich WD, Keane RW. Neuroprotective effects of bone morphogenetic protein 7 (BMP7) treatment after spinal cord injury. Neurosci Lett 2009; 465:226-9. [PMID: 19765637 DOI: 10.1016/j.neulet.2009.09.013] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2009] [Revised: 08/31/2009] [Accepted: 09/11/2009] [Indexed: 11/16/2022]
Abstract
Bone morphogenetic protein 7 (BMP7) has been shown to ameliorate reduced dendritic growth induced by glutamate excitotoxicity in neuronal tissue cultures and/or provide an enhancement of functional recovery in central nervous system (CNS) injury. BMP7 expression is modulated by spinal cord injury (SCI), but the molecular mechanisms involved in neuroprotection have not been clearly defined. Here, we show that BMP7 treatment of rats subjected to mild cervical SCI significantly increased the pro-survival mitogen-activated protein kinase-38 (MAPK-38) pathway and levels of N-methyl-D-aspartate receptor 1 (NMDAR-1) resulting in a significant increase in neuronal sparing in the ventral horn of the spinal cord. Moreover, BMP7 was neuroprotective against glutamate-mediated excitotoxicity in cultured cortical neurons. These studies show that BMP7 administration may be used as a therapeutic strategy to reduce the damaging excitotoxic effects following SCI.
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Affiliation(s)
- Juan Pablo de Rivero Vaccari
- Department of Neurological Surgery, University of Miami Miller School of Medicine, Miami, FL 33136, United States
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