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Chen T, Li Y, Ren X, Wang Y. The mGluR5-mediated Arc activation protects against experimental traumatic brain injury in rats. CNS Neurosci Ther 2024; 30:e14695. [PMID: 39107945 PMCID: PMC11303269 DOI: 10.1111/cns.14695] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2023] [Revised: 03/05/2024] [Accepted: 03/11/2024] [Indexed: 08/10/2024] Open
Abstract
INTRODUCTION Traumatic brain injury (TBI) is a complex pathophysiological process, and increasing attention has been paid to the important role of post-synaptic density (PSD) proteins, such as glutamate receptors. Our previous study showed that a PSD protein Arc/Arg3.1 (Arc) regulates endoplasmic reticulum (ER) stress and neuronal necroptosis in traumatic injury in vitro. AIM In this study, we investigated the expression, regulation and biological function of Arc in both in vivo and in vitro experimental TBI models. RESULTS Traumatic neuronal injury (TNI) induced a temporal upregulation of Arc in cortical neurons, while TBI resulted in sustained increase in Arc expression up to 24 h in rats. The increased expression of Arc was mediated by the activity of metabotropic glutamate receptor 5 (mGluR5), but not dependent on the intracellular calcium (Ca2+) release. By using inhibitors and antagonists, we found that TNI regulates Arc expression via Gq protein and protein turnover. In addition, overexpression of Arc protects against TBI-induced neuronal injury and motor dysfunction both in vivo and in vitro, whereas the long-term cognitive function was not altered. To determine the role of Arc in mGluR5-induced protection, lentivirus-mediated short hairpin RNA (shRNA) transfection was performed to knockdown Arc expression. The mGluR5 agonist (RS)-2-chloro-5-hydroxyphenylglycine (CHPG)-induced protection against TBI was partially prevented by Arc knockdown. Furthermore, the CHPG-induced attenuation of Ca2+ influx after TNI was dependent on Arc activation and followed regulation of AMPAR subunits. The results of Co-IP and Ca2+ imaging showed that the Arc-Homer1 interaction contributes to the CHPG-induced regulation of intracellular Ca2+ release. CONCLUSION In summary, the present data indicate that the mGluR5-mediated Arc activation is a protective mechanism that attenuates neurotoxicity following TBI through the regulation of intracellular Ca2+ hemostasis. The AMPAR-associated Ca2+ influx and ER Ca2+ release induced by Homer1-IP3R pathway might be involved in this protection.
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Affiliation(s)
- Tao Chen
- Department of NeurosurgeryWuxi Taihu Hospital, Wuxi Clinical Medical School of Anhui Medical UniversityWuxiChina
| | - Yun‐Fei Li
- Department of NeurosurgeryWuxi Taihu Hospital, Wuxi Clinical Medical School of Anhui Medical UniversityWuxiChina
| | - Xu Ren
- Department of NeurosurgeryWuxi Taihu Hospital, Wuxi Clinical Medical School of Anhui Medical UniversityWuxiChina
| | - Yu‐Hai Wang
- Department of NeurosurgeryWuxi Taihu Hospital, Wuxi Clinical Medical School of Anhui Medical UniversityWuxiChina
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2
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Malyshev AV, Pavshintcev VV, Mitkin NA, Sukhanova IA, Gedzun VR, Zlobin AS, Doronin II, Babkin GA, Sawyer TK. The novel peptide LCGM-10 attenuates metabotropic glutamate receptor 5 activity and demonstrates behavioral effects in animal models. Front Behav Neurosci 2024; 18:1333258. [PMID: 38385004 PMCID: PMC10879279 DOI: 10.3389/fnbeh.2024.1333258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2023] [Accepted: 01/24/2024] [Indexed: 02/23/2024] Open
Abstract
We employed a structural bioinformatics approach to develop novel peptides with predicted affinity to the binding site for negative allosteric modulators (NAMs) of metabotropic glutamate receptor 5 (mGluR5). Primary screening in zebrafish (Danio rerio) revealed a stimulatory effect of two peptides, LCGM-10 and LCGM-15. Target validation studies using calcium ion flux imaging and a luciferase reporter assay confirmed mGluR5 as the target. LCGM-10 showed greater potency than LCGM-15; it was comparable to that of the mGluR5 NAM 2-methyl-6-(phenylethynyl) pyridine (MPEP). Rodent behavioral screening in the open field and elevated plus maze revealed increased locomotor activity in both tests after acute LCGM-10 treatment, supported by further analysis of home cage spontaneous locomotor activity (SLA). The stimulating effect of a single LCGM-10 administration on SLA was evident up to 60 min after administration and was not accompanied by hypokinetic rebound observed for caffeine. According to our results, LCGM-10 has therapeutic potential to treat hypo- and dyskinesias of various etiologies. Further investigation of LCGM-10 effects in the delay discounting model of impulsive choice in rats revealed reduced trait impulsivity after single and chronic administrations, suggesting potential implication for attention deficit hyperactivity disorder, obsessive compulsive disorder, and addictions.
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Balbi M, Bonanno G, Bonifacino T, Milanese M. The Physio-Pathological Role of Group I Metabotropic Glutamate Receptors Expressed by Microglia in Health and Disease with a Focus on Amyotrophic Lateral Sclerosis. Int J Mol Sci 2023; 24:ijms24065240. [PMID: 36982315 PMCID: PMC10048889 DOI: 10.3390/ijms24065240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Revised: 03/03/2023] [Accepted: 03/06/2023] [Indexed: 03/30/2023] Open
Abstract
Microglia cells are the resident immune cells of the central nervous system. They act as the first-line immune guardians of nervous tissue and central drivers of neuroinflammation. Any homeostatic alteration that can compromise neuron and tissue integrity could activate microglia. Once activated, microglia exhibit highly diverse phenotypes and functions related to either beneficial or harmful consequences. Microglia activation is associated with the release of protective or deleterious cytokines, chemokines, and growth factors that can in turn determine defensive or pathological outcomes. This scenario is complicated by the pathology-related specific phenotypes that microglia can assume, thus leading to the so-called disease-associated microglia phenotypes. Microglia express several receptors that regulate the balance between pro- and anti-inflammatory features, sometimes exerting opposite actions on microglial functions according to specific conditions. In this context, group I metabotropic glutamate receptors (mGluRs) are molecular structures that may contribute to the modulation of the reactive phenotype of microglia cells, and this is worthy of exploration. Here, we summarize the role of group I mGluRs in shaping microglia cells' phenotype in specific physio-pathological conditions, including some neurodegenerative disorders. A significant section of the review is specifically focused on amyotrophic lateral sclerosis (ALS) since it represents an entirely unexplored topic of research in the field.
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Affiliation(s)
- Matilde Balbi
- Department of Pharmacy (DIFAR), University of Genoa, Viale Cembrano 4, 16148 Genova, Italy
| | - Giambattista Bonanno
- Department of Pharmacy (DIFAR), University of Genoa, Viale Cembrano 4, 16148 Genova, Italy
- IRCCS Ospedale Policlinico San Martino, Largo Rosanna Benzi 10, 16132 Genoa, Italy
| | - Tiziana Bonifacino
- Department of Pharmacy (DIFAR), University of Genoa, Viale Cembrano 4, 16148 Genova, Italy
- Inter-University Center for the Promotion of the 3Rs Principles in Teaching & Research (Centro 3R), 56122 Pisa, Italy
| | - Marco Milanese
- Department of Pharmacy (DIFAR), University of Genoa, Viale Cembrano 4, 16148 Genova, Italy
- IRCCS Ospedale Policlinico San Martino, Largo Rosanna Benzi 10, 16132 Genoa, Italy
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Schroeder ME, Bassett DS, Meaney DF. A multilayer network model of neuron-astrocyte populations in vitro reveals mGluR5 inhibition is protective following traumatic injury. Netw Neurosci 2022; 6:499-527. [PMID: 35733423 PMCID: PMC9208011 DOI: 10.1162/netn_a_00227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Accepted: 01/04/2022] [Indexed: 11/16/2022] Open
Abstract
Astrocytes communicate bidirectionally with neurons, enhancing synaptic plasticity and promoting the synchronization of neuronal microcircuits. Despite recent advances in understanding neuron-astrocyte signaling, little is known about astrocytic modulation of neuronal activity at the population level, particularly in disease or following injury. We used high-speed calcium imaging of mixed cortical cultures in vitro to determine how population activity changes after disruption of glutamatergic signaling and mechanical injury. We constructed a multilayer network model of neuron-astrocyte connectivity, which captured distinct topology and response behavior from single-cell-type networks. mGluR5 inhibition decreased neuronal activity, but did not on its own disrupt functional connectivity or network topology. In contrast, injury increased the strength, clustering, and efficiency of neuronal but not astrocytic networks, an effect that was not observed in networks pretreated with mGluR5 inhibition. Comparison of spatial and functional connectivity revealed that functional connectivity is largely independent of spatial proximity at the microscale, but mechanical injury increased the spatial-functional correlation. Finally, we found that astrocyte segments of the same cell often belong to separate functional communities based on neuronal connectivity, suggesting that astrocyte segments function as independent entities. Our findings demonstrate the utility of multilayer network models for characterizing the multiscale connectivity of two distinct but functionally dependent cell populations. Astrocytes communicate bidirectionally with neurons, enhancing synaptic plasticity and promoting the synchronization of neuronal microcircuits. We constructed a multilayer network model of neuron-astrocyte connectivity based on calcium activity in mixed cortical cultures, and used this model to evaluate the effect of glutamatergic inhibition and mechanical injury on network topology. We found that injury increased the strength, clustering, and efficiency of neuronal but not astrocytic networks, an effect that was not observed in injured networks pretreated with a glutamate receptor antagonist. Our findings demonstrate the utility of multilayer network models for characterizing the multiscale connectivity of two distinct but functionally dependent cell populations.
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Affiliation(s)
- Margaret E. Schroeder
- Department of Bioengineering, School of Engineering & Applied Science, University of Pennsylvania, Philadelphia, PA, USA
| | - Danielle S. Bassett
- Department of Bioengineering, School of Engineering & Applied Science, University of Pennsylvania, Philadelphia, PA, USA
- Department of Physics & Astronomy, College of Arts & Sciences, University of Pennsylvania, Philadelphia, PA, USA
- Department of Electrical & Systems Engineering, School of Engineering & Applied Science, University of Pennsylvania, Philadelphia, PA, USA
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - David F. Meaney
- Department of Bioengineering, School of Engineering & Applied Science, University of Pennsylvania, Philadelphia, PA, USA
- Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
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5
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Schiel KA. A beneficial role for elevated extracellular glutamate in Amyotrophic Lateral Sclerosis and cerebral ischemia. Bioessays 2021; 43:e2100127. [PMID: 34585427 DOI: 10.1002/bies.202100127] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 09/03/2021] [Accepted: 09/08/2021] [Indexed: 11/06/2022]
Abstract
This hypothesis proposes that increased extracellular glutamate in Amyotrophic Lateral Sclerosis (ALS) and cerebral ischemia, currently viewed as a trigger for excitotoxicity, is actually beneficial as it stimulates the utilization of glutamate as metabolic fuel. Renewed appreciation of glutamate oxidation by ischemic neurons has raised questions regarding the role of extracellular glutamate in ischemia. Is it detrimental, as suggested by excitotoxicity in early in vitro studies, or beneficial, as suggested by its oxidation in later in vivo studies? The answer may depend on the activity of N-methyl-D-aspartate (NMDA) glutamate receptors. Early in vitro procedures co-activated NMDA receptors (NMDARs) containing 2A (GluN2A) and 2B (GluN2B) subunits, an event now believed to trigger excitotoxicity; however, during in vivo ischemia D-serine and zinc molecules are released and these ensure only GluN2B receptors are stimulated. This not only prevents excitotoxicity but also initiates signaling cascades that allow ischemic neurons to import and oxidize glutamate.
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6
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Wang Y, Gu L, Yang HM, Zhang H. Cystic fibrosis transmembrane conductance regulator-associated ligand protects dopaminergic neurons by differentially regulating metabotropic glutamate receptor 5 in the progression of neurotoxin 6-hydroxydopamine-induced Parkinson's disease model. Neurotoxicology 2021; 84:14-29. [PMID: 33571554 DOI: 10.1016/j.neuro.2021.02.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2020] [Revised: 12/21/2020] [Accepted: 02/04/2021] [Indexed: 10/22/2022]
Abstract
Due to limitations in early diagnosis and treatments of Parkinson's disease (PD), it is necessary to explore the neuropathological changes that occur early in PD progression and to design neuroprotective therapies to prevent or delay the ongoing degeneration process. Metabotropic glutamate receptor 5 (mGlu5) has shown both diagnostic and therapeutic potential in preclinical studies on PD. Clinical trials using mGlu5 negative allosteric modulators to treat PD have, however, raised limitations about the neuroprotective role of mGlu5. It is likely that mGlu5 has different regulatory roles in different stages of PD. Here, we investigated a protective role of cystic fibrosis transmembrane conductance regulator-associated ligand (CAL) in the progression of PD by differential regulation of mGlu5 expression and activity to protect against 6-hydroxydopamine (6-OHDA)-induced neurotoxicity. Following treatment with 6-OHDA, mGlu5 and CAL expressions were elevated in the early stage and reduced in the late stage, both in vitro and in vivo. Activation of mGlu5 in the early stage by (RS)-2-chloro-5-hydroxyphenylglycine, or blocking mGlu5 in the late stage by 2-methyl-6-(phenylethynyl) pyridine, increased cell survival and inhibited apoptosis, but these effects were significantly weakened by knockdown of CAL. CAL alleviated 6-OHDA-induced neurotoxicity by regulating mGlu5-mediated signaling pathways, thereby maintaining the physiological function of mGlu5 in different disease stages. In PD rat model, CAL deficiency aggravated 6-OHDA toxicity on dopaminergic neurons and increased motor dysfunction because of lack of regulation of mGlu5 activity. These data reveal a potential mechanism by which CAL specifically regulates the opposite activity of mGlu5 in progression of PD to protect against neurotoxicity, suggesting that CAL is a favorable endogenous target for the treatment of PD.
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Affiliation(s)
- Yuan Wang
- Department of Neurobiology, School of Basic Medical Sciences, Beijing Key Laboratory of Neural Regeneration and Repair, Beijing Institute for Brain Disorders, Capital Medical University, No. 10 Xitoutiao, You An Men, Beijing, 100069, China
| | - Li Gu
- Department of Neurobiology, School of Basic Medical Sciences, Beijing Key Laboratory of Neural Regeneration and Repair, Beijing Institute for Brain Disorders, Capital Medical University, No. 10 Xitoutiao, You An Men, Beijing, 100069, China
| | - Hui Min Yang
- Department of Neurobiology, School of Basic Medical Sciences, Beijing Key Laboratory of Neural Regeneration and Repair, Beijing Institute for Brain Disorders, Capital Medical University, No. 10 Xitoutiao, You An Men, Beijing, 100069, China
| | - Hong Zhang
- Department of Neurobiology, School of Basic Medical Sciences, Beijing Key Laboratory of Neural Regeneration and Repair, Beijing Institute for Brain Disorders, Capital Medical University, No. 10 Xitoutiao, You An Men, Beijing, 100069, China.
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7
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Niu Y, Zeng X, Qin G, Zhang D, Zhou J, Chen L. Downregulation of metabotropic glutamate receptor 5 alleviates central sensitization by activating autophagy via inhibiting mTOR pathway in a rat model of chronic migraine. Neurosci Lett 2020; 743:135552. [PMID: 33352285 DOI: 10.1016/j.neulet.2020.135552] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 11/30/2020] [Accepted: 12/02/2020] [Indexed: 12/20/2022]
Abstract
Central sensitization is one of the important pathological mechanisms of chronic migraine (CM). Metabolic glutamate receptor 5 (mGluR5) mediates pain by activating various intracellular pathways. However, whether mGluR5 contributes to central sensitization in CM and the exact mechanism remains unclear. Male rats were used to establish a CM model by repeated infusions of inflammatory soup (IS) for 7 days to stimulate the activation of the dural nociceptor. The mechanical and thermal thresholds were used to evaluate allodynia, and central sensitization was assessed by measuring calcitonin gene-related peptide (CGRP) and substance P (SP). Microtubule associated protein 1 light chain 3 (LC3) and p62/SQSTM1 were used to assess autophagy. We found that the expression of mGluR5 in the trigeminal nucleus caudalis (TNC) of CM rats was significantly increased. In addition, the downregulation of mGluR5 activated autophagy by inhibiting the mTOR pathway. Moreover, the activation of autophagy alleviated allodynia and central sensitization in CM rats. This study identified a novel strategy for the treatment of CM; the downregulation of mGluR5 in a rat model of CM decreased the expression of the inflammatory factor interleukin-1 beta (IL-1β) and the central sensitization-associated proteins CGRP and SP by activating autophagy via inhibiting the mTOR pathway.
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Affiliation(s)
- Yingying Niu
- Laboratory Research Center, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Xiaoxu Zeng
- Laboratory Research Center, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Guangcheng Qin
- Laboratory Research Center, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Dunke Zhang
- Laboratory Research Center, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Jiying Zhou
- Department of Neurology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Lixue Chen
- Laboratory Research Center, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China.
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8
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Rahman MS, Yang J, Luan Y, Qiu Z, Zhang J, Lu H, Chen X, Liu Y. Attenuation of Acute Intracerebral Hemorrhage-Induced Microglial Activation and Neuronal Death Mediated by the Blockade of Metabotropic Glutamate Receptor 5 In Vivo. Neurochem Res 2020; 45:1230-1243. [PMID: 32140955 DOI: 10.1007/s11064-020-03006-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 02/21/2020] [Accepted: 02/29/2020] [Indexed: 12/12/2022]
Abstract
The activation of microglia in response to intracerebral hemorrhagic stroke is one of the principal components of the progression of this disease. It results in the formation of pro-inflammatory cytokines that lead to neuronal death, a structural deterioration that, in turn interferes with functional recovery. Metabotropic glutamate receptor 5 (mGluR5) is highly expressed in reactive microglia and is involved in the pathological processes of brain disorders, but its role in intracerebral hemorrhage (ICH) remains unknown. We hypothesized that mGluR5 regulates microglial activation and ICH maintenance. In this study, collagenase-induced ICH mice received a single intraperitoneal injection of the mGluR5 antagonist-, MTEP, or vehicle 2 h after injury. We found that acute ICH upregulated mGluR5 and microglial activation. mGluR5 was highly localized in reactive microglia in the peri-hematomal cortex and striatum on days 3 and 7 post-ICH. The MTEP-mediated pharmacological inhibition of mGluR5 in vivo resulted in the substantial attenuation of acute microglial activation and IL-6, and TNF-α release. We also showed that the blockade of mGluR5 markedly reduced cell apoptosis, and neurodegeneration and markedly elevated neuroprotection. Furthermore, the MTEP-mediated inhibition of mGluR5 significantly reduced the lesion volume and improved functional recovery. Taken together, our results demonstrate that ICH injury enhances mGluR5 expression in the acute and subacute stages and that mGluR5 is highly localized in reactive microglia. The blockade of mGluR5 reduces ICH-induced acute microglial activation, provides neuroprotection and promotes neurofunctional recovery after ICH. The inhibition of mGluR5 may be a relevant therapeutic target for intracerebral hemorrhagic stroke.
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Affiliation(s)
- Md Saidur Rahman
- Institute of Neurobiology, Xi'an Jiaotong University Health Science Center, 76 West Yanta Road, Xi'an, 710061, Shaanxi, People's Republic of China.,Department of Anatomy and Histology, Patuakhali Science and Technology University, Dhaka, Bangladesh
| | - Jianbo Yang
- Department of Neurology, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, People's Republic of China
| | - Yan Luan
- Institute of Neurobiology, Xi'an Jiaotong University Health Science Center, 76 West Yanta Road, Xi'an, 710061, Shaanxi, People's Republic of China
| | - Zhengguo Qiu
- Department of Anesthesiology, The Second Affiliated Hospital of Xi'an Medical University, Xi'an, 710038, Shaanxi, People's Republic of China
| | - Jianshui Zhang
- Institute of Neurobiology, Xi'an Jiaotong University Health Science Center, 76 West Yanta Road, Xi'an, 710061, Shaanxi, People's Republic of China
| | - Haixia Lu
- Institute of Neurobiology, Xi'an Jiaotong University Health Science Center, 76 West Yanta Road, Xi'an, 710061, Shaanxi, People's Republic of China
| | - Xinlin Chen
- Institute of Neurobiology, Xi'an Jiaotong University Health Science Center, 76 West Yanta Road, Xi'an, 710061, Shaanxi, People's Republic of China.
| | - Yong Liu
- Institute of Neurobiology, Xi'an Jiaotong University Health Science Center, 76 West Yanta Road, Xi'an, 710061, Shaanxi, People's Republic of China.
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9
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Bhat SA, Henry RJ, Blanchard AC, Stoica BA, Loane DJ, Faden AI. Enhanced Akt/GSK-3β/CREB signaling mediates the anti-inflammatory actions of mGluR5 positive allosteric modulators in microglia and following traumatic brain injury in male mice. J Neurochem 2020; 156:225-248. [PMID: 31926033 DOI: 10.1111/jnc.14954] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Revised: 12/16/2019] [Accepted: 01/02/2020] [Indexed: 12/20/2022]
Abstract
We have previously shown that treatment with a mGluR5 positive allosteric modulator (PAM) is neuroprotective after experimental traumatic brain injury (TBI), limiting post-traumatic neuroinflammation by reducing pro-inflammatory microglial activation and promoting anti-inflammatory and neuroprotective responses. However, the specific molecular mechanisms governing this anti-inflammatory shift in microglia remain unknown. Here we show that the mGluR5 PAM, VU0360172 (VuPAM), regulates microglial inflammatory responses through activation of Akt, resulting in the inhibition of GSK-3β. GSK-3β regulates the phosphorylation of CREB, thereby controlling the expression of inflammation-related genes and microglial plasticity. The anti-inflammatory action of VuPAM in microglia is reversed by inhibiting Akt/GSK-3β/CREB signaling. Using a well-characterized TBI model and CX3CR1gfp/+ mice to visualize microglia in vivo, we demonstrate that VuPAM enhances Akt/GSK-3β/CREB signaling in the injured cortex, as well as anti-inflammatory microglial markers. Furthermore, in situ analysis revealed that GFP + microglia in the cortex of VuPAM-treated TBI mice co-express pCREB and the anti-inflammatory microglial phenotype marker YM1. Taken together, our data show that VuPAM decreases pro-inflammatory microglial activation by modulating Akt/GSK-3β/CREB signaling. These findings serve to clarify the potential neuroprotective mechanisms of mGluR5 PAM treatment after TBI, and suggest novel therapeutic targets for post-traumatic neuroinflammation. Cover Image for this issue: https://doi.org/10.1111/jnc.15048.
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Affiliation(s)
- Shahnawaz A Bhat
- Department of Anesthesiology and Shock, Trauma and Anesthesiology Research (STAR) Center, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Rebecca J Henry
- Department of Anesthesiology and Shock, Trauma and Anesthesiology Research (STAR) Center, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Alexa C Blanchard
- Department of Anesthesiology and Shock, Trauma and Anesthesiology Research (STAR) Center, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Bogdan A Stoica
- Department of Anesthesiology and Shock, Trauma and Anesthesiology Research (STAR) Center, University of Maryland School of Medicine, Baltimore, MD, USA
| | - David J Loane
- Department of Anesthesiology and Shock, Trauma and Anesthesiology Research (STAR) Center, University of Maryland School of Medicine, Baltimore, MD, USA.,School of Biochemistry and Immunology, Trinity Biomedical Sciences Institute, Trinity College, Dublin, Ireland
| | - Alan I Faden
- Department of Anesthesiology and Shock, Trauma and Anesthesiology Research (STAR) Center, University of Maryland School of Medicine, Baltimore, MD, USA
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10
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Zhu L, Zhu J, Guo SW. Homer1/mGluR1-mediated ER stress contributes to lysophosphatidic acid-induced neurotoxicity in cortical neurons. Neurochem Int 2019; 129:104515. [DOI: 10.1016/j.neuint.2019.104515] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Revised: 07/15/2019] [Accepted: 07/29/2019] [Indexed: 11/29/2022]
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11
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Sun Y, Feng X, Ding Y, Li M, Yao J, Wang L, Gao Z. Phased Treatment Strategies for Cerebral Ischemia Based on Glutamate Receptors. Front Cell Neurosci 2019; 13:168. [PMID: 31105534 PMCID: PMC6499003 DOI: 10.3389/fncel.2019.00168] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2019] [Accepted: 04/08/2019] [Indexed: 11/23/2022] Open
Abstract
Extracellular glutamate accumulation following cerebral ischemia leads to overactivation of glutamate receptors, thereby resulting in intracellular Ca2+ overload and excitotoxic neuronal injury. Multiple attempts have been made to counteract such effects by reducing glutamate receptor function, but none have been successful. In this minireview, we present the available evidence regarding the role of all types of ionotropic and metabotropic glutamate receptors in cerebral ischemia and propose phased treatment strategies based on glutamate receptors in both the acute and post-acute phases of cerebral ischemia, which may help realize the clinical application of glutamate receptor antagonists.
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Affiliation(s)
- Yongjun Sun
- Department of Pharmacy, Hebei University of Science and Technology, Shijiazhuang, China.,Hebei Research Center of Pharmaceutical and Chemical Engineering, Hebei University of Science and Technology, Shijiazhuang, China
| | - Xue Feng
- Hebei University of Science and Technology, Shijiazhuang, China
| | - Yue Ding
- Shijiazhuang Vocational College of Technology and Information, Shijiazhuang, China
| | - Mengting Li
- Department of Pharmacy, Hebei University of Science and Technology, Shijiazhuang, China
| | - Jun Yao
- Department of Pharmacy, Hebei University of Science and Technology, Shijiazhuang, China
| | - Long Wang
- Department of Family and Consumer Sciences, California State University, Long Beach, CA, United States
| | - Zibin Gao
- Department of Pharmacy, Hebei University of Science and Technology, Shijiazhuang, China.,State Key Laboratory Breeding Base-Hebei Province Key Laboratory of Molecular Chemistry for Drug, Shijiazhuang, China
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12
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Qian M, Wouters E, Dalton JAR, Risseeuw MDP, Crans RAJ, Stove C, Giraldo J, Van Craenenbroeck K, Van Calenbergh S. Synthesis toward Bivalent Ligands for the Dopamine D 2 and Metabotropic Glutamate 5 Receptors. J Med Chem 2018; 61:8212-8225. [PMID: 30180563 DOI: 10.1021/acs.jmedchem.8b00671] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
In this study, we designed and synthesized heterobivalent ligands targeting heteromers consisting of the metabotropic glutamate 5 receptor (mGluR5) and the dopamine D2 receptor (D2R). Bivalent ligand 22a with a linker consisting of 20 atoms showed 4-fold increase in affinity for cells coexpressing D2R and mGluR5 compared to cells solely expressing D2R. Likewise, the affinity of 22a for mGluR5 increased 2-fold in the coexpressing cells. Additionally, 22a exhibited a 5-fold higher mGluR5 affinity than its monovalent precursor 21a in cells coexpressing D2R and mGluR5. These results indicate that 22a is able to bridge binding sites on both receptors constituting the heterodimer. Likewise, cAMP assays revealed that 22a had a 4-fold higher potency in stable D2R and mGluR5 coexpressing cell lines than 1. Furthermore, molecular modeling reveals that 22a is able to simultaneously bind both receptors by passing between the TM5-TM6 interface and establishing six protein-ligand H-bonds.
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Affiliation(s)
- Mingcheng Qian
- Laboratory for Medicinal Chemistry (FFW) , Ghent University , Ottergemsesteenweg 460 , B-9000 Ghent , Belgium.,Laboratory of Toxicology , Ghent University , Ottergemsesteenweg 460 , B-9000 Ghent , Belgium
| | - Elise Wouters
- Laboratory of Toxicology , Ghent University , Ottergemsesteenweg 460 , B-9000 Ghent , Belgium
| | - James A R Dalton
- Laboratory of Molecular Neuropharmacology and Bioinformatics, Unitat de Bioestadística, Institut de Neurociències , Universitat Autònoma de Barcelona , 08193 Bellaterra , Spain.,Instituto de Salud Carlos III, Centro de Investigación Biomédica en Red de Salud Mental, CIBERSAM , Universitat Autònoma de Barcelona , 08193 Bellaterra , Spain.,Unitat de Neurociència Traslacional, Parc Taulí Hospital Universitari, Institut d'Investigació i Innovació Parc Taulí (I3PT), Institut de Neurociències , Universitat Autònoma de Barcelona , 08193 Bellaterra , Spain
| | - Martijn D P Risseeuw
- Laboratory for Medicinal Chemistry (FFW) , Ghent University , Ottergemsesteenweg 460 , B-9000 Ghent , Belgium
| | - René A J Crans
- Laboratory of Toxicology , Ghent University , Ottergemsesteenweg 460 , B-9000 Ghent , Belgium
| | - Christophe Stove
- Laboratory of Toxicology , Ghent University , Ottergemsesteenweg 460 , B-9000 Ghent , Belgium
| | - Jesús Giraldo
- Laboratory of Molecular Neuropharmacology and Bioinformatics, Unitat de Bioestadística, Institut de Neurociències , Universitat Autònoma de Barcelona , 08193 Bellaterra , Spain.,Instituto de Salud Carlos III, Centro de Investigación Biomédica en Red de Salud Mental, CIBERSAM , Universitat Autònoma de Barcelona , 08193 Bellaterra , Spain.,Unitat de Neurociència Traslacional, Parc Taulí Hospital Universitari, Institut d'Investigació i Innovació Parc Taulí (I3PT), Institut de Neurociències , Universitat Autònoma de Barcelona , 08193 Bellaterra , Spain
| | | | - Serge Van Calenbergh
- Laboratory for Medicinal Chemistry (FFW) , Ghent University , Ottergemsesteenweg 460 , B-9000 Ghent , Belgium
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13
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Gao F, Wang B, Chang T, Li M, Fang W, Li ZH, Gao L. The iron pro-chelator BHAPI attenuates glutamate-induced oxidative stress via Wnt-β/catenin pathway in HT22 cells. Brain Res Bull 2018; 139:285-291. [PMID: 29588166 DOI: 10.1016/j.brainresbull.2018.03.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Accepted: 03/22/2018] [Indexed: 01/07/2023]
Abstract
Disturbances in intracellular iron homeostasis are associated with brain damage under various neuropathological conditions. However, exposure of neuronal cells to classical iron chelators could interfere with physiological iron functions in the brain. Thus, iron pro-chelators represent a more advanced approach to exert strong free-iron binding capacity only under oxidative stress conditions. In the present study, we investigated the protective effects of an iron pro-chelator BHAPI [(E)-N'-(1-(2-((4- (4,4,5,5-tetramethyl-1,2,3-dioxoborolan-2-yl)benzyl)oxy)phenyl)ethylidene) isonicotino hydrazide] against glutamate-induced toxicity in neuronal HT22 cells. The results showed that BHAPI significantly increased cell viability, decreased lactate dehydrogenase (LDH) release, inhibited apoptotic cell death and reduced the activation of caspase-3 after glutamate treatment. This protection was accompanied by the preservation of mitochondrial function, as evidenced by reduced mitochondrial oxidative stress, attenuated lipid peroxidation and enhanced ATP generation. In addition, BHAPI promoted Wnt/β-catenin signaling, which was related to destabilization of β-catenin destruction complex. The Wnt/β-catenin signaling inhibitor JW74, but not IWP2, partially prevented the protective effects of BHAPI. In conclusion, our data suggested that BHAPI acted as a neuroprotective agent against glutamate-induced toxicity, and this protection might be mediated by preservation of mitochondrial function and regulation of Wnt/β-catenin pathway.
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Affiliation(s)
- Fei Gao
- Department of Neurosurgery, Tangdu Hospital, Fourth Military Medical University, Xi'an, Shaanxi, 710038, China
| | - Bao Wang
- Department of Neurosurgery, Tangdu Hospital, Fourth Military Medical University, Xi'an, Shaanxi, 710038, China
| | - Tao Chang
- Department of Neurosurgery, Tangdu Hospital, Fourth Military Medical University, Xi'an, Shaanxi, 710038, China
| | - Min Li
- Department of Neurosurgery, Tangdu Hospital, Fourth Military Medical University, Xi'an, Shaanxi, 710038, China
| | - Wei Fang
- Department of Neurosurgery, Tangdu Hospital, Fourth Military Medical University, Xi'an, Shaanxi, 710038, China
| | - Zhi-Hong Li
- Department of Neurosurgery, Tangdu Hospital, Fourth Military Medical University, Xi'an, Shaanxi, 710038, China
| | - Li Gao
- Department of Neurosurgery, Tangdu Hospital, Fourth Military Medical University, Xi'an, Shaanxi, 710038, China.
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14
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Metabotropic glutamate receptor 5 deficiency inhibits neutrophil infiltration after traumatic brain injury in mice. Sci Rep 2017; 7:9998. [PMID: 28855570 PMCID: PMC5577182 DOI: 10.1038/s41598-017-10201-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Accepted: 08/07/2017] [Indexed: 11/08/2022] Open
Abstract
Both brain native inflammatory cells and infiltrated peripheral white blood cells (WBCs) are primary participants in the brain inflammatory damage post-TBI. Metabotropic glutamate receptor 5 (mGluR5) has been reported to regulate microglias and astrocytes to affect inflammation after TBI, but its effect on modulating infiltrated peripheral WBCs remains unclear. In a mouse moderate TBI model, we found that mGluR5 knockout (KO) significantly reduced neutrophil infiltration and inflammatory cytokine expression in the brain at 24 hours post TBI, which was accompanied by improved neurological dysfunction. Further investigation indicated that mGluR5 KO reduced the permeability of blood-brain barrier (BBB), the entrance for neutrophils to enter brain, and markedly decreased the mRNA levels of neutrophil-associated chemokines in brain tissue, including CXCL1, CXCL2, CCL2, CCL4 and CCL5. Using brain microvascular endothelial cells (BMECs), neutrophils and a BBB model in vitro, we confirmed the inhibitory effect of mGluR5 deficiency on neutrophil infiltration and demonstrated that blockade of protein kinase C (PKC) signaling was involved in it. These results provide insight into the role of mGluR5 in the regulation of inflammation in the acute phase of TBI, which may provide novel clues for TBI therapy.
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15
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Ye X, Yu L, Zuo D, Zhang L, Zu J, Hu J, Tang J, Bao L, Cui C, Zhang R, Jin G, Zan K, Zhang Z, Yang X, Shi H, Zhang Z, Xiao Q, Liu Y, Xiang J, Zhang X, Cui G. Activated mGluR5 protects BV2 cells against OGD/R induced cytotoxicity by modulating BDNF-TrkB pathway. Neurosci Lett 2017. [PMID: 28642149 DOI: 10.1016/j.neulet.2017.06.029] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Activated Metabotropic glutamate receptors 5(mGluR5) exhibits protective effects against ischemic brain damage, but the underlying mechanisms are not clearly known. Brain-derived neurotrophic factor (BDNF), as a valuable member of neurotrophic factor family, exerts its protection by combining with its high-affinity receptor tyrosine protein kinase B (TrkB). To investigate the role of activated mGluR5 against oxygen-glucose deprivation (OGD)/reoxygenation (R)-mediated cytotoxicity, the cell viability, apoptosis, the release of inflammatory cytokines and accumulation of reactive oxygen species (ROS) were evaluated in BV2 cells (Microglia cell line) with or without OGD/R exposure. Our data show that CHPG (the selective mGluR5 agonist) pretreatment, as an mGluR5 agonist, protected BV2 cells against OGD/R-induced cytotoxicity, apoptosis, the release of inflammatory cytokines, and the accumulation of ROS. However, these effects were significantly reversed by the mGluR5 antagonist MPEP pretreatment. Our data also show that the expressions of BDNF and TrkB were significantly decreased in BV2 cells with OGD/R exposure. CHPG pretreatment significantly enhanced the expressions of BDNF and TrkB in BV2 cells with OGD/R exposure. However, the increased expressions were significantly abrogated by MPEP pretreatment. In addition, inhibition of BDNF/TrKB pathway by K252a also attenuated the protective effects of activated mGluR5 against OGD/R-induced cytotoxicity, apoptosis and the release of inflammatory cytokines. Morever, pretreatment with exogenous BDNF protected BV2 cells against OGD/R induced apoptosis and release of inflammatory cytokines. These data suggested that BDNF/TrKB pathway may be involved in regulating activated mGluR5' protective effects against OGD/R induced cytotoxicity in BV2 cells.
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Affiliation(s)
- Xinchun Ye
- Department of Neurology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, Jiangsu Province, 221004, China
| | - Lu Yu
- Department of Neurology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, Jiangsu Province, 221004, China
| | - Dandan Zuo
- Department of Neurology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, Jiangsu Province, 221004, China
| | - Liang Zhang
- Department of Neurology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, Jiangsu Province, 221004, China
| | - Jie Zu
- Department of Neurology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, Jiangsu Province, 221004, China
| | - Jinxia Hu
- Department of Neurology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, Jiangsu Province, 221004, China
| | - Jiao Tang
- Department of Neurology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, Jiangsu Province, 221004, China
| | - Lei Bao
- Department of Neurology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, Jiangsu Province, 221004, China
| | - Chengcheng Cui
- Department of Neurology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, Jiangsu Province, 221004, China
| | - Ruixue Zhang
- Department of Neurology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, Jiangsu Province, 221004, China
| | - Guoliang Jin
- Department of Neurology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, Jiangsu Province, 221004, China
| | - Kun Zan
- Department of Neurology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, Jiangsu Province, 221004, China
| | - Zuohui Zhang
- Department of Neurology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, Jiangsu Province, 221004, China
| | - Xinxin Yang
- Department of Neurology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, Jiangsu Province, 221004, China
| | - Hongjuan Shi
- Department of Neurology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, Jiangsu Province, 221004, China
| | - Zunsheng Zhang
- Department of Neurology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, Jiangsu Province, 221004, China
| | - Qihua Xiao
- Department of Neurology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, Jiangsu Province, 221004, China
| | - Yonghai Liu
- Department of Neurology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, Jiangsu Province, 221004, China
| | - Jie Xiang
- Department of Rehabilitation, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, Jiangsu Province, 221004, China
| | - Xueling Zhang
- Department of Neurology, Suqian People's Hospital, Suqian, Jiangsu Province, 223800, China
| | - Guiyun Cui
- Department of Neurology, The Affiliated Hospital of Xuzhou Medical University, Xuzhou, Jiangsu Province, 221004, China.
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16
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The Orally Active Noncompetitive AMPAR Antagonist Perampanel Attenuates Focal Cerebral Ischemia Injury in Rats. Cell Mol Neurobiol 2017; 38:459-466. [PMID: 28401316 DOI: 10.1007/s10571-017-0489-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Accepted: 03/24/2017] [Indexed: 02/07/2023]
Abstract
Inhibition of ionotropic glutamate receptors (iGluRs) is a potential target of therapy for ischemic stroke. Perampanel is a potent noncompetitive α-amino-3-hydroxy-5-methyl-4-isoxazole propionate receptor (AMPAR) antagonist with good oral bioavailability and favorable pharmacokinetic properties. Here, we investigated the potential protective effects of perampanel against focal cerebral ischemia in a middle cerebral artery occlusion (MCAO) model in rats. Oral administration with perampanel significantly reduced MCAO-induced brain edema, brain infarct volume, and neuronal apoptosis. These protective effects were associated with improved functional outcomes, as measured by foot-fault test, adhesive removal test, and modified neurological severity score (mNSS) test. Importantly, perampanel was effective even when the administration was delayed to 1 h after reperfusion. The results of enzyme-linked immunosorbent assay (ELISA) showed that perampanel significantly decreased the expression of pro-inflammatory cytokines IL-1β and TNF-α, whereas it increased the levels of anti-inflammatory cytokines IL-10 and TGF-β1 after MCAO. In addition, perampanel treatment markedly decreased the expression of inducible nitric oxide synthase (iNOS) and neuronal nitric oxide synthase (nNOS), and also inhibited nitric oxide (NO) generation in MCAO-injured rats at 24 and 72 h after reperfusion. In conclusion, this study demonstrated that the orally active AMPAR antagonist perampanel protects against experimental ischemic stroke via regulating inflammatory cytokines and NOS pathways.
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17
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Li D, Tong L, Kawano H, Liu N, Yan HJ, Zhao L, Li HP. Regulation and role of ERK phosphorylation in glial cells following a nigrostriatal pathway injury. Brain Res 2016; 1648:90-100. [PMID: 27402431 DOI: 10.1016/j.brainres.2016.07.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Revised: 06/30/2016] [Accepted: 07/07/2016] [Indexed: 02/05/2023]
Abstract
This study was undertaken to examine the function of extracellular signal-regulated kinase (ERK) signaling pathway on the proliferation and activation of microglia/macrophage and astrocytes after brain injury in mice. The result of Western blot showed that p-ERK was immediately activated after injury (<4h), but the duration was short (<4 days). According to immunofluorescence double staining, it was found that at 4 and 8h after injury, p-ERK was expressed in microglia/macrophages, and that more cells were co-expressed by p-ERK and IBA-1 (microglia/macrophage marker) at 8h; at days 1 and 4, p-ERK was expressed in astrocytes, and more cells were co-expressed by p-ERK and GFAP (astrocyte marker) at day 4. After injury, the mice were injected with U0126 (MAPK/ERK signaling pathway inhibitor) via the femoral vein. Compared with those injected with DMSO, the cell number co-expressed by p-ERK and IBA-1 or GFAP significantly decreased (P<0.05). The increase of microglia/macrophage and astrocyte caused by injury was remitted, and the positive cell number significantly decreased (P<0.05). Western blot showed that the expression quantity of IBA-1 and GFAP significantly decreased (P<0.05). Furthermore, the ERK signaling pathway was involved in the proliferation and activation of the two glial cells types and improved long-term neurobehavioral function after brain injury. Therefore, the exploration of the formation mechanism of glial scar after injury and further research on the therapeutic method of neural regeneration are essential.
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Affiliation(s)
- Dan Li
- Department of Human Anatomy, College of Basic Medical Sciences, China Medical University, Shenyang, China
| | - Lei Tong
- Department of Human Anatomy, College of Basic Medical Sciences, China Medical University, Shenyang, China
| | - Hitoshi Kawano
- Department of Health and Dietetics, Faculty of Health and Medical Science. Teikyo Heisei University, Tokyo 170-8445, Japan
| | - Nan Liu
- Department of Human Anatomy, College of Basic Medical Sciences, China Medical University, Shenyang, China
| | - Hong-Jing Yan
- Department of Human Anatomy, College of Basic Medical Sciences, China Medical University, Shenyang, China
| | - Liang Zhao
- Department of Human Anatomy, College of Basic Medical Sciences, China Medical University, Shenyang, China
| | - Hong-Peng Li
- Department of Human Anatomy, College of Basic Medical Sciences, China Medical University, Shenyang, China.
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18
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Abstract
Globally, greater than 30 million individuals are afflicted with disorders of the nervous system accompanied by tens of thousands of new cases annually with limited, if any, treatment options. Erythropoietin (EPO) offers an exciting and novel therapeutic strategy to address both acute and chronic neurodegenerative disorders. EPO governs a number of critical protective and regenerative mechanisms that can impact apoptotic and autophagic programmed cell death pathways through protein kinase B (Akt), sirtuins, mammalian forkhead transcription factors, and wingless signaling. Translation of the cytoprotective pathways of EPO into clinically effective treatments for some neurodegenerative disorders has been promising, but additional work is necessary. In particular, development of new treatments with erythropoiesis-stimulating agents such as EPO brings several important challenges that involve detrimental vascular outcomes and tumorigenesis. Future work that can effectively and safely harness the complexity of the signaling pathways of EPO will be vital for the fruitful treatment of disorders of the nervous system.
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Affiliation(s)
- Kenneth Maiese
- Cellular and Molecular Signaling, Newark, New Jersey 07101
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19
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Loane DJ, Kumar A. Microglia in the TBI brain: The good, the bad, and the dysregulated. Exp Neurol 2015; 275 Pt 3:316-327. [PMID: 26342753 DOI: 10.1016/j.expneurol.2015.08.018] [Citation(s) in RCA: 471] [Impact Index Per Article: 52.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Revised: 08/05/2015] [Accepted: 08/25/2015] [Indexed: 01/24/2023]
Abstract
As the major cellular component of the innate immune system in the central nervous system (CNS) and the first line of defense whenever injury or disease occurs, microglia play a critical role in neuroinflammation following a traumatic brain injury (TBI). In the injured brain microglia can produce neuroprotective factors, clear cellular debris and orchestrate neurorestorative processes that are beneficial for neurological recovery after TBI. However, microglia can also become dysregulated and can produce high levels of pro-inflammatory and cytotoxic mediators that hinder CNS repair and contribute to neuronal dysfunction and cell death. The dual role of microglial activation in promoting beneficial and detrimental effects on neurons may be accounted for by their polarization state and functional responses after injury. In this review article we discuss emerging research on microglial activation phenotypes in the context of acute brain injury, and the potential role of microglia in phenotype-specific neurorestorative processes such as neurogenesis, angiogenesis, oligodendrogenesis and regeneration. We also describe some of the known molecular mechanisms that regulate phenotype switching, and highlight new therapeutic approaches that alter microglial activation state balance to enhance long-term functional recovery after TBI. An improved understanding of the regulatory mechanisms that control microglial phenotypic shifts may advance our knowledge of post-injury recovery and repair, and provide opportunities for the development of novel therapeutic strategies for TBI.
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Affiliation(s)
- David J Loane
- Department of Anesthesiology, University of Maryland School of Medicine, Baltimore, MD, United States; Shock, Trauma, and Anesthesiology Research (STAR) Center, University of Maryland School of Medicine, Baltimore, MD, United States.
| | - Alok Kumar
- Department of Anesthesiology, University of Maryland School of Medicine, Baltimore, MD, United States; Shock, Trauma, and Anesthesiology Research (STAR) Center, University of Maryland School of Medicine, Baltimore, MD, United States
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20
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mGluR5 protect astrocytes from ischemic damage in postnatal CNS white matter. Cell Calcium 2015; 58:423-30. [PMID: 26189008 PMCID: PMC4634333 DOI: 10.1016/j.ceca.2015.06.010] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2015] [Revised: 06/26/2015] [Accepted: 06/28/2015] [Indexed: 11/21/2022]
Abstract
Astrocytes perform essential neuron-supporting functions in the central nervous system (CNS) and their disruption has devastating effects on neuronal integrity in multiple neuropathologies. Although astrocytes are considered resistant to most pathological insults, ischemia can result in astrocyte injury and astrocytes in postnatal white matter are particularly vulnerable. Metabotropic glutamate receptors (mGluR) are neuroprotective in ischemia and are widely expressed by astrocytes throughout CNS grey matter, but their potential cytoprotective role in astrocytes had not been determined. Here, we identify functional expression of group I mGluR in white matter astrocytes and demonstrate their activation protects astrocytes from ischemic damage in the postnatal mouse optic nerve. Optic nerve astrocytes are shown to express mGluR5 using immunolabelling of sections and explant cultures from transgenic reporter mice in which GFAP drives expression of EGFP. In addition, using Fluo-4 calcium imaging in isolated intact optic nerves, we show that the group I/II mGluR agonist ACPD and the specific group I mGluR agonist DHPG evoke glial Ca(2+) signals that were significantly inhibited by the group I mGluR antagonist AIDA. A key finding is that activation of group I mGluR protects astrocytes against oxygen-glucose deprivation (OGD) in situ, in isolated intact optic nerves from GFAP-EGFP mice. This study identifies a role for group I mGluR in protecting astrocytes against ischemia in postnatal white matter and suggests this may be a strategy for limiting damage in neuropathologies involving excitotoxity.
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21
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Qiu JL, Zhu WL, Lu YJ, Bai ZF, Liu ZG, Zhao P, Sun C, Zhang YB, Li H, Liu W. The selective mGluR5 agonist CHPG attenuates SO2-induced oxidative stress and inflammation through TSG-6/NF-κB pathway in BV2 microglial cells. Neurochem Int 2015; 85-86:46-52. [PMID: 25953665 DOI: 10.1016/j.neuint.2015.04.007] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Revised: 04/24/2015] [Accepted: 04/28/2015] [Indexed: 11/16/2022]
Abstract
Sulfur dioxide (SO2) is a common air pollutant and can cause harmful insults on neurons. Microglial activation has been implicated in the signaling cascades that contribute to neuronal cell death in various neurological disorders. In the present study, we found that SO2 derivatives decreased cell viability via inducing oxidative stress, inflammatory responses and apoptotic cell death in BV2 microglial cells. Pretreatment with (RS)-2-chloro-5-hydroxyphenylglycine (CHPG), an mGluR5 agonist, significantly attenuated the SO2-induced cytotoxicity, which was fully prevented by the mGluR5 antagonist MPEP. CHPG increased the expression of TNF-α stimulated gene/protein 6 (TSG-6), but decreased the activation of nuclear factor-κB (NF-κB) after SO2 derivatives treatment in BV2 cells. In addition, knockdown of TSG-6 expression by specific targeted short interfering RNA (siRNA) partially reversed the protection induced by CHPG. Therefore, our findings reveal a mechanistic basis for exploring the association between SO2 exposure and neurological disorders, and also for opening up therapeutic approaches of ameliorating neuronal injury resulting from exposure in atmospheric polluting environment.
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Affiliation(s)
- Jun-Ling Qiu
- Basic Medical Sciences Research Center, Shannxi Fourth People's Hospital, Xi'an, Shannxi 710043, China
| | - Wen-Li Zhu
- Department of Neurology, Shannxi Fourth People's Hospital, Xi'an, Shannxi 710043, China
| | - Yu-Jie Lu
- Basic Medical Sciences Research Center, Shannxi Fourth People's Hospital, Xi'an, Shannxi 710043, China
| | - Zheng-Fa Bai
- Basic Medical Sciences Research Center, Shannxi Fourth People's Hospital, Xi'an, Shannxi 710043, China
| | - Zhi-Gang Liu
- Department of Neurosurgery, Shannxi Fourth People's Hospital, Xi'an, Shannxi 710043, China
| | - Pei Zhao
- Department of Neurology, Shannxi Fourth People's Hospital, Xi'an, Shannxi 710043, China
| | - Chao Sun
- Basic Medical Sciences Research Center, Shannxi Fourth People's Hospital, Xi'an, Shannxi 710043, China
| | - Ya-Bin Zhang
- Basic Medical Sciences Research Center, Shannxi Fourth People's Hospital, Xi'an, Shannxi 710043, China
| | - Hua Li
- Department of Neurosurgery, Shannxi Fourth People's Hospital, Xi'an, Shannxi 710043, China.
| | - Wei Liu
- Basic Medical Sciences Research Center, Shannxi Fourth People's Hospital, Xi'an, Shannxi 710043, China.
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22
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Activation of mGluR5 Attenuates Microglial Activation and Neuronal Apoptosis in Early Brain Injury After Experimental Subarachnoid Hemorrhage in Rats. Neurochem Res 2015; 40:1121-32. [DOI: 10.1007/s11064-015-1572-7] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2015] [Revised: 03/27/2015] [Accepted: 04/01/2015] [Indexed: 12/23/2022]
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23
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Guan DF, Ren PY, Hu W, Zhang YL. The mGluR5 Positive Allosteric Modulator CDPPB Inhibits SO2-Induced Protein Radical Formation and Mitochondrial Dysfunction Through Activation of Akt in Mouse Hippocampal HT22 Cells. Cell Mol Neurobiol 2014; 35:573-83. [DOI: 10.1007/s10571-014-0153-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Accepted: 12/23/2014] [Indexed: 11/30/2022]
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24
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Hu W, Guan LS, Dang XB, Ren PY, Zhang YL. Small-molecule inhibitors at the PSD-95/nNOS interface attenuate MPP+-induced neuronal injury through Sirt3 mediated inhibition of mitochondrial dysfunction. Neurochem Int 2014; 79:57-64. [PMID: 25452082 DOI: 10.1016/j.neuint.2014.10.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Revised: 10/03/2014] [Accepted: 10/20/2014] [Indexed: 11/18/2022]
Abstract
Post-synaptic density protein 95 (PSD-95) links neuronal nitric oxide synthase (nNOS) with the N-methyl-D-aspartic acid (NMDA) receptor in the central nervous system, and this molecular complex has been implicated in regulating neuronal excitability in several neurological disorders. Here, small-molecule inhibitors of the PSD-95/nNOS interaction, IC87201 and ZL006 were tested for neuroprotective effects in an in vitro Parkinson's disease (PD) model. We now report that IC87201 and ZL006 reduced MPP(+)-induced neuronal injury and apoptotic cell death in a dose-dependent manner in cultured cortical neurons. These protective effects were associated with suppressed mitochondrial dysfunction, as evidenced by decreased reactive oxygen species (ROS) generation, cytochrome c release, mitochondrial membrane potential (MMP) collapse, and the preserved mitochondrial complex I activity and ATP synthesis. IC87201 and ZL006 also preserved intracellular homeostasis through mitigating mitochondrial Ca(2+) uptake and promoting mitochondrial Ca(2+) buffering capacity. Moreover, treatment with IC87201 and ZL006 significantly increased the expression of Sirt3 after MPP(+) exposure, and knockdown of Sirt3 using specific targeted small interfere RNA (siRNA) partially nullified the protective effects induced by these two inhibitors. These data strongly support the hypothesis that targeting the PSD-95/nNOS interaction produces neuroprotective effects and may represent a novel class of therapeutics for PD as well as other neurological diseases where detrimental NMDA receptor signaling plays a major role.
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Affiliation(s)
- Wei Hu
- Xi'an Jiaotong University Health Science Center, 76 Yanta West Road, Xi'an, Shannxi 710061, China; Department of Emergency, Shaanxi Provincial People's Hospital, The Third Affiliated Hospital, School of Medicine, Xi'an Jiaotong University, Xi'an, Shaanxi 710068, China
| | - Lai-Shun Guan
- Department of Neurosurgery, Shaanxi Provincial People's Hospital, The Third Affiliated Hospital, School of Medicine, Xi'an Jiaotong University, Xi'an, Shaanxi 710068, China
| | - Xing-Bo Dang
- Department of Neurosurgery, Shaanxi Provincial People's Hospital, The Third Affiliated Hospital, School of Medicine, Xi'an Jiaotong University, Xi'an, Shaanxi 710068, China
| | - Peng-Yu Ren
- Department of Orthopaedics, The Second Affiliated Hospital, School of Medicine, Xi'an Jiaotong University, Xi'an, Shaanxi 710068, China
| | - Yue-Lin Zhang
- Department of Neurosurgery, Shaanxi Provincial People's Hospital, The Third Affiliated Hospital, School of Medicine, Xi'an Jiaotong University, Xi'an, Shaanxi 710068, China.
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25
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Hou PF, Liu ZH, Li N, Cheng WJ, Guo SW. Knockdown of STIM1 improves neuronal survival after traumatic neuronal injury through regulating mGluR1-dependent Ca(2+) signaling in mouse cortical neurons. Cell Mol Neurobiol 2014; 35:283-92. [PMID: 25304289 DOI: 10.1007/s10571-014-0123-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Accepted: 10/05/2014] [Indexed: 01/05/2023]
Abstract
Activation of glutamate receptors and followed increase of intracellular calcium concentration is a key pathological mechanism involved in secondary neuronal injury after traumatic brain injury (TBI). Stromal interaction molecule (STIM) proteins are considered to be important players in regulating neuronal Ca(2+) homeostasis under normal aging and pathological conditions. Here, we investigated the role of STIM1 in regulating metabotropic glutamate receptor 1 (mGluR1)-related Ca(2+) signaling and neuronal survival by using an in vitro traumatic neuronal injury (TNI) model. The expression of STIM1 was significantly increased at both mRNA and protein levels after TNI. Down-regulation of STIM1 by specific small interfere RNA significantly preserved neuronal viability, decreased lactate dehydrogenase release, and inhibited apoptotic cell death after traumatic injury. Moreover, knockdown of STIM1 significantly alleviated the mGluR1-related increase of cytoplasmic Ca(2+) levels after TNI. By analyzing Ca(2+) imaging in Ca(2+)-free conditions, we demonstrated that the mGluR1-dependent inositol trisphosphate receptor and/or ryanodine receptor-mediated Ca(2+) release from the endoplasmic reticulum after TNI is strongly attenuated in the absence of STIM1. Together, our results demonstrate that in the mammalian nervous system, STIM1 is a key regulator of mGluR1-dependent Ca(2+) signaling and knockdown of STIM1 might be an effective intervention target in TBI.
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Affiliation(s)
- Peng-Fei Hou
- Department of Neurosurgery, The First Affiliated Hospital of Xi'an Jiaotong University, 277 West Yanta Road, Xi'an, 710061, Shaanxi, China
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Loane DJ, Stoica BA, Tchantchou F, Kumar A, Barrett JP, Akintola T, Xue F, Conn PJ, Faden AI. Novel mGluR5 positive allosteric modulator improves functional recovery, attenuates neurodegeneration, and alters microglial polarization after experimental traumatic brain injury. Neurotherapeutics 2014; 11:857-69. [PMID: 25096154 PMCID: PMC4391388 DOI: 10.1007/s13311-014-0298-6] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Traumatic brain injury (TBI) causes microglial activation and related neurotoxicity that contributes to chronic neurodegeneration and loss of neurological function. Selective activation of metabotropic glutamate receptor 5 (mGluR5) by the orthosteric agonist (RS)-2-chloro-5-hydroxyphenylglycine (CHPG), is neuroprotective in experimental models of TBI, and has potent anti-inflammatory effects in vitro. However, the therapeutic potential of CHPG is limited due to its relatively weak potency and brain permeability. Highly potent, selective and brain penetrant mGluR5 positive allosteric modulators (PAMs) have been developed and show promise as therapeutic agents. We evaluated the therapeutic potential of a novel mGluR5 PAM, VU0360172, after controlled cortical impact (CCI) in mice. Vehicle, VU0360172, or VU0360172 plus mGluR5 antagonist (MTEP), were administered systemically to CCI mice at 3 h post-injury; lesion volume, hippocampal neurodegeneration, microglial activation, and functional recovery were assessed through 28 days post-injury. Anti-inflammatory effects of VU0360172 were also examined in vitro using BV2 and primary microglia. VU0360172 treatment significantly reduced the lesion, attenuated hippocampal neurodegeneration, and improved motor function recovery after CCI. Effects were mediated by mGluR5 as co-administration of MTEP blocked the protective effects of VU0360172. VU0360172 significantly reduced CD68 and NOX2 expression in activated microglia in the cortex at 28 days post-injury, and also suppressed pro-inflammatory signaling pathways in BV2 and primary microglia. In addition, VU0360172 treatment shifted the balance between M1/M2 microglial activation states towards an M2 pro-repair phenotype. This study demonstrates that VU0360172 confers neuroprotection after experimental TBI, and suggests that mGluR5 PAMs may be promising therapeutic agents for head injury.
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Affiliation(s)
- David J. Loane
- />Department of Anesthesiology and Center for Shock, Trauma, and Anesthesiology Research (STAR), University of Maryland School of Medicine, Health Sciences Facility II (HSFII), #S247, 20 Penn Street, Baltimore, MD 21201 USA
| | - Bogdan A. Stoica
- />Department of Anesthesiology and Center for Shock, Trauma, and Anesthesiology Research (STAR), University of Maryland School of Medicine, Health Sciences Facility II (HSFII), #S247, 20 Penn Street, Baltimore, MD 21201 USA
| | - Flaubert Tchantchou
- />Department of Anesthesiology and Center for Shock, Trauma, and Anesthesiology Research (STAR), University of Maryland School of Medicine, Health Sciences Facility II (HSFII), #S247, 20 Penn Street, Baltimore, MD 21201 USA
| | - Alok Kumar
- />Department of Anesthesiology and Center for Shock, Trauma, and Anesthesiology Research (STAR), University of Maryland School of Medicine, Health Sciences Facility II (HSFII), #S247, 20 Penn Street, Baltimore, MD 21201 USA
| | - James P. Barrett
- />Department of Anesthesiology and Center for Shock, Trauma, and Anesthesiology Research (STAR), University of Maryland School of Medicine, Health Sciences Facility II (HSFII), #S247, 20 Penn Street, Baltimore, MD 21201 USA
| | - Titilola Akintola
- />Department of Anesthesiology and Center for Shock, Trauma, and Anesthesiology Research (STAR), University of Maryland School of Medicine, Health Sciences Facility II (HSFII), #S247, 20 Penn Street, Baltimore, MD 21201 USA
| | - Fengtian Xue
- />Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, MD USA
| | - P. Jeffrey Conn
- />Department of Pharmacology and Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical Center, Nashville, TN USA
| | - Alan I. Faden
- />Department of Anesthesiology and Center for Shock, Trauma, and Anesthesiology Research (STAR), University of Maryland School of Medicine, Health Sciences Facility II (HSFII), #S247, 20 Penn Street, Baltimore, MD 21201 USA
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Activation of mGluR5 attenuates NMDA-induced neurotoxicity through disruption of the NMDAR-PSD-95 complex and preservation of mitochondrial function in differentiated PC12 cells. Int J Mol Sci 2014; 15:10892-907. [PMID: 24941251 PMCID: PMC4100187 DOI: 10.3390/ijms150610892] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2014] [Revised: 05/16/2014] [Accepted: 05/30/2014] [Indexed: 01/05/2023] Open
Abstract
Glutamate-mediated toxicity is implicated in various neuropathologic conditions, and activation of ionotropic and metabotropic glutamate receptors is considered to be the most important mechanism. It has been reported that pharmacological saturation of metabotropic glutamate receptors (mGluRs) can facilitate N-methyl-d-aspartate receptor (NMDAR) related signaling cascades, but the mechanism leading to mGluR-NMDAR interactions in excitotoxic neuronal injury has remained unidentified. In the present study, we investigated the role of mGluR5 in the regulation of N-methyl-d-aspartate (NMDA)-induced excitotoxicity in differentiated PC12 cells. We found that activation of mGluR5 with the specific agonist R,S-2-chloro-5-hydroxyphenylglycine (CHPG) increased cell viability and inhibited lactate dehydrogenase (LDH) release in a dose-dependent manner. CHPG also inhibited an increase in the Bax/Bcl-2 ratio, attenuated cleavage of caspase-9 and caspase-3, and reduced apoptotic cell death after NMDA treatment. The NMDA-induced mitochondrial dysfunction, as indicated by mitochondrial reactive oxygen species (ROS) generation, collapse of mitochondrial membrane potential (MMP), and cytochrome c release, was also partly prevented by CHPG treatment. Furthermore, CHPG blocked the NMDA-induced interaction of NMDAR with postsynaptic density protein-95 (PSD-95), but had no effects on intracellular calcium concentrations. All these results indicated that activation of mGluR5 protects differentiated PC12 cells from NMDA-induced neuronal excitotoxicity by disrupting NMDAR-PSD-95 interaction, which might be an ideal target for investigating therapeutic strategies in various neurological diseases where excitotoxicity may contribute to their pathology.
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Ginsenoside Rd attenuates mitochondrial permeability transition and cytochrome C release in isolated spinal cord mitochondria: involvement of kinase-mediated pathways. Int J Mol Sci 2014; 15:9859-77. [PMID: 24897022 PMCID: PMC4100126 DOI: 10.3390/ijms15069859] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Revised: 05/08/2014] [Accepted: 05/21/2014] [Indexed: 12/17/2022] Open
Abstract
Ginsenoside Rd (Rd), one of the main active ingredients in Panax ginseng, has multifunctional activity via different mechanisms and neuroprotective effects that are exerted probably via its antioxidant or free radical scavenger action. However, the effects of Rd on spinal cord mitochondrial dysfunction and underlying mechanisms are still obscure. In this study, we sought to investigate the in vitro effects of Rd on mitochondrial integrity and redox balance in isolated spinal cord mitochondria. We verified that Ca2+ dissipated the membrane potential, provoked mitochondrial swelling and decreased NAD(P)H matrix content, which were all attenuated by Rd pretreatment in a dose-dependent manner. In contrast, Rd was not able to inhibit Ca2+ induced mitochondrial hydrogen peroxide generation. The results of Western blot showed that Rd significantly increased the expression of p-Akt and p-ERK, but had no effects on phosphorylation of PKC and p38. In addition, Rd treatment significantly attenuated Ca2+ induced cytochrome c release, which was partly reversed by antagonists of Akt and ERK, but not p-38 inhibitor. The effects of bisindolylmaleimide, a PKC inhibitor, on Rd-induced inhibition of cytochrome c release seem to be at the level of its own detrimental activity on mitochondrial function. Furthermore, we also found that pretreatment with Rd in vivo (10 and 50 mg/kg) protected spinal cord mitochondria against Ca2+ induced mitochondrial membrane potential dissipation and cytochrome c release. It is concluded that Rd regulate mitochondrial permeability transition pore formation and cytochrome c release through protein kinases dependent mechanism involving activation of intramitochondrial Akt and ERK pathways.
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Luo P, Chen T, Zhao Y, Zhang L, Yang Y, Liu W, Li S, Rao W, Dai S, Yang J, Fei Z. Postsynaptic scaffold protein Homer 1a protects against traumatic brain injury via regulating group I metabotropic glutamate receptors. Cell Death Dis 2014; 5:e1174. [PMID: 24722299 PMCID: PMC5424101 DOI: 10.1038/cddis.2014.116] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2013] [Revised: 02/11/2014] [Accepted: 02/19/2014] [Indexed: 12/22/2022]
Abstract
Traumatic brain injury (TBI) produces excessive glutamate, leading to excitotoxicity via the activation of glutamate receptors. Postsynaptic density scaffold proteins have crucial roles in mediating signal transduction from glutamate receptors to their downstream mediators. Therefore, studies on the mechanisms underlying regulation of excitotoxicity by scaffold proteins can uncover new treatments for TBI. Here, we demonstrated that the postsynaptic scaffold protein Homer 1a was neuroprotective against TBI in vitro and in vivo, and this neuroprotection was associated with its effects on group I metabotropic glutamate receptors (mGluRs). Upon further study, we found that Homer 1a mainly affected neuronal injury induced by mGluR1 activation after TBI and also influenced mGluR5 function when its activity was restored. The ability of Homer 1a to disrupt mGluR-ERK signaling contributed to its ability to regulate the functions of mGluR1 and mGluR5 after traumatic injury. Intracellular Ca(2+) and PKC were two important factors involved in the mediation of mGluR-ERK signaling by Homer 1a. These results define Homer 1a as a novel endogenous neuroprotective agent against TBI.
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Affiliation(s)
- P Luo
- Department of Neurosurgery, Xijing Hospital, Fourth Military Medical University, Xi'an, People's Republic of China
| | - T Chen
- Department of Neurosurgery, Xijing Hospital, Fourth Military Medical University, Xi'an, People's Republic of China
| | - Y Zhao
- Department of Neurosurgery, Xijing Hospital, Fourth Military Medical University, Xi'an, People's Republic of China
| | - L Zhang
- Department of Neurosurgery, Xijing Hospital, Fourth Military Medical University, Xi'an, People's Republic of China
| | - Y Yang
- Department of Neurosurgery, Xijing Hospital, Fourth Military Medical University, Xi'an, People's Republic of China
| | - W Liu
- Department of Neurosurgery, Xijing Hospital, Fourth Military Medical University, Xi'an, People's Republic of China
| | - S Li
- Department of Neurosurgery, Xijing Hospital, Fourth Military Medical University, Xi'an, People's Republic of China
| | - W Rao
- Department of Neurosurgery, Xijing Hospital, Fourth Military Medical University, Xi'an, People's Republic of China
| | - S Dai
- Department of Neurosurgery, Xijing Hospital, Fourth Military Medical University, Xi'an, People's Republic of China
| | - J Yang
- Department of Surgery, Boston Veterans Affairs Healthcare System, Boston University School of Medicine, Boston, MA, USA
| | - Z Fei
- Department of Neurosurgery, Xijing Hospital, Fourth Military Medical University, Xi'an, People's Republic of China
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Li B, Xiao L, Wang ZY, Zheng PS. Knockdown of STIM1 inhibits 6-hydroxydopamine-induced oxidative stress through attenuating calcium-dependent ER stress and mitochondrial dysfunction in undifferentiated PC12 cells. Free Radic Res 2014; 48:758-68. [PMID: 24720513 DOI: 10.3109/10715762.2014.905687] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Stromal interaction molecule (STIM) proteins are parts of elaborate eukaryotic Ca(2+) signaling systems and are considered to be important players in regulating neuronal Ca(2+) homeostasis under normal ageing and pathological conditions. Here, we investigated the potential role of STIM1 in 6-hydroxydopamine (6-OHDA)-induced toxicity in undifferentiated PC12 cell lines. Cells exposed to 6-OHDA demonstrated alterations in the generation of reactive oxygen species (ROS) in a Ca(2+)-dependent manner. Downregulation of STIM1 expression by specific small interfering RNA (siRNA) attenuated apoptotic cell death, reduced intracellular ROS production, and partially prevented the impaired endogenous antioxidant enzyme activities after 6-OHDA treatment. Furthermore, STIM1 knockdown significantly attenuated 6-OHDA-induced intracellular Ca(2+) overload by inhibiting endogenous store-operated calcium entry (SOCE). The effect of STIM1 siNRA on SOCE was related to orai1 and L-type Ca(2+) channels, but not to transient receptor potential canonical type 1 (TRPC1) channel. In addition, silencing of STIM1 increased the Ca(2+) buffering capacity of the endoplasmic reticulum (ER) in 6-OHDA-injured cells. ER vacuoles formed from the destruction of ER structural integrity and activation of ER-related apoptotic factors (CHOP and Caspase-12) were partially prevented by STIM1 knockdown. Moreover, STIM1 knockdown attenuated 6-OHDA-induced mitochondrial Ca(2+) uptake and mitochondrial dysfunction, including the collapse of mitochondrial membrane potential (MMP) and the decrease of ATP generation. Taken together, our data provide the first evidence that inhibition of STIM1-meditated intracellular Ca(2+) dyshomeostasis protects undifferentiated PC12 cells against 6-OHDA toxicity and indicate that STIM1 may be responsible for neuronal oxidative stress induced by ER stress and mitochondrial dysfunction in PD.
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Affiliation(s)
- B Li
- Department of Reproductive Medicine, the First Affiliated Hospital of Medical School, Xi'an Jiaotong University , Xi'an, Shaanxi , The People's Republic of China
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Neuroprotective effect of allicin against traumatic brain injury via Akt/endothelial nitric oxide synthase pathway-mediated anti-inflammatory and anti-oxidative activities. Neurochem Int 2014; 68:28-37. [DOI: 10.1016/j.neuint.2014.01.015] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2013] [Revised: 12/31/2013] [Accepted: 01/07/2014] [Indexed: 12/18/2022]
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Zhang C, Zhu J, Zhang J, Li H, Zhao Z, Liao Y, Wang X, Su J, Sang S, Yuan X, Liu Q. Neuroprotective and anti-apoptotic effects of valproic acid on adult rat cerebral cortex through ERK and Akt signaling pathway at acute phase of traumatic brain injury. Brain Res 2014; 1555:1-9. [PMID: 24508577 DOI: 10.1016/j.brainres.2014.01.051] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2013] [Revised: 01/27/2014] [Accepted: 01/29/2014] [Indexed: 01/06/2023]
Abstract
Mood stabilizer valproic acid (VPA), a widely used antiepileptic drug that has been demonstrated neuroprotective effect against various insults through multiple signaling pathways. The role of VPA in traumatic brain injury (TBI) remains unclear. In the present study, we investigated the neuroprotective potency of VPA for protection against TBI in adult rats, focusing on studying signaling mediators of two well characterized pro-survival molecules, extracellular signal-regulated protein kinase (ERK) and Akt. We found that treatment of VPA after TBI significantly attenuated brain edema, reduced contusion volume and the rate of neuronal apoptosis. The treatment also partly blocked an increase in capase-3 activity. VPA markedly up-regulated the activity of ERK and Akt expression. Moreover, treatment with either PD98059, an ERK inhibitor and/or LY294002, an Akt inhibitor, attenuated the neuroprotection of VPA against TBI to varying degrees. Taken together, these results demonstrated that treatment with VPA after TBI could be neuroprotective via activation of ERK and Akt signaling pathways.
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Affiliation(s)
- Chi Zhang
- Department of Neurosurgery, Xiangya Hospital, Central-South University, Changsha, Hunan 410008, PR China
| | - Jie Zhu
- Department of Neurosurgery, 101th Hospital of PLA, Rescue Center of Craniocerebral Injuries of PLA, Wuxi, Jiangsu 214044, PR China
| | - Jing Zhang
- Department of Otorhinolaryngology, Head and Neck Surgery, Lanzhou General Hospital of Lanzhou Military Command, Lanzhou, Gansu 730050, PR China
| | - Haoyu Li
- Department of Neurosurgery, Xiangya Hospital, Central-South University, Changsha, Hunan 410008, PR China
| | - Zijin Zhao
- Department of Neurosurgery, Xiangya Hospital, Central-South University, Changsha, Hunan 410008, PR China
| | - Yiwei Liao
- Department of Neurosurgery, Xiangya Hospital, Central-South University, Changsha, Hunan 410008, PR China
| | - Xiangyu Wang
- Department of Neurosurgery, Xiangya Hospital, Central-South University, Changsha, Hunan 410008, PR China
| | - Jun Su
- Department of Neurosurgery, Xiangya Hospital, Central-South University, Changsha, Hunan 410008, PR China
| | - Shushan Sang
- Department of Neurosurgery, Xiangya Hospital, Central-South University, Changsha, Hunan 410008, PR China
| | - Xianrui Yuan
- Department of Neurosurgery, Xiangya Hospital, Central-South University, Changsha, Hunan 410008, PR China.
| | - Qing Liu
- Department of Neurosurgery, Xiangya Hospital, Central-South University, Changsha, Hunan 410008, PR China.
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Fu J, Fan HB, Guo Z, Wang Z, Li XD, Li J, Pei GX. Salvianolic acid B attenuates spinal cord ischemia-reperfusion-induced neuronal injury and oxidative stress by activating the extracellular signal-regulated kinase pathway in rats. J Surg Res 2013; 188:222-30. [PMID: 24387840 DOI: 10.1016/j.jss.2013.11.1118] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2013] [Revised: 11/22/2013] [Accepted: 11/27/2013] [Indexed: 11/25/2022]
Abstract
BACKGROUND Salvianolic acid B (SalB), the main bioactive compound isolated from the traditional Chinese medicinal herb broad Radix Salviae Miltiorrhizae exerts a spectrum of pharmacologic activities. We investigated the effects of SalB treatment in a rat model of spinal cord ischemia and reperfusion (I/R) injury and the underlying mechanism. MATERIALS AND METHODS SalB was administered at 1, 10, or 50 mg/kg after spinal cord ischemia. The potential protective effects on spinal cord injury were determined by spinal cord edema, infarct volume, and motor function assessment of the hind limbs. RESULTS SalB treatment significantly decreased spinal cord edema and infarct volume and preserved motor function of the hind limbs in a dose-dependent manner. SalB administration ameliorated the generation of oxidative products and preserved antioxidant defense activities in the injured spinal cord at both 4 and 24 h after I/R injury. Moreover, SalB prolonged the I/R injury-induced activation of extracellular signal-regulated kinase (ERK), and blocking ERK activation with PD98059 partially prevented the neuroprotective effects of SalB. CONCLUSIONS These findings demonstrate the neuroprotective effects of SalB in a spinal cord I/R injury model and suggest that SalB-induced neuroprotection was mediated by ERK activation.
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Affiliation(s)
- Jun Fu
- Department of Orthopaedic Oncology, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Hong-bin Fan
- Department of Orthopaedic Oncology, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Zheng Guo
- Department of Orthopaedic Oncology, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China.
| | - Zhen Wang
- Department of Orthopaedic Oncology, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China.
| | - Xiang-dong Li
- Department of Orthopaedic Oncology, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Jing Li
- Department of Orthopaedic Oncology, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China
| | - Guo-xian Pei
- Department of Orthopaedic Oncology, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi, China
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Zhao W, Ho L, Varghese M, Yemul S, Dams-O'Connor K, Gordon W, Knable L, Freire D, Haroutunian V, Pasinetti GM. Decreased level of olfactory receptors in blood cells following traumatic brain injury and potential association with tauopathy. J Alzheimers Dis 2013; 34:417-429. [PMID: 23241557 DOI: 10.3233/jad-121894] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Traumatic brain injury (TBI) is a leading cause of death and disability among children and young adults in the United States. In this study, we explored whether changes in the gene expression profile of peripheral blood mononuclear cells (PBMC) may provide a clinically assessable "window" into the brain, reflecting molecular alterations following TBI that might contribute to the onset and progression of TBI clinical complications. We identified three olfactory receptor (OR) TBI biomarkers that are aberrantly down-regulated in PBMC specimens from TBI subjects. Down-regulation of these OR biomarkers in PBMC was correlated with the severity of brain injury and TBI-specific symptoms. A two- biomarker panel comprised of OR11H1 and OR4M1 provided the best criterion for segregating the TBI and control cases with 90% accuracy, 83.3% sensitivity, and 100% specificity. We found that the OR biomarkers are ectopically expressed in multiple brain regions, including the entorhinal-hippocampus system known to play an important role in memory formation and consolidation. Activation of OR4M1 led to attenuation of abnormal tau phosphorylation, possibly through JNK signaling pathway. Our results suggested that addition of the two-OR biomarker model to current diagnostic criteria may lead to improved TBI detection for clinical trials, and decreased expression of OR TBI biomarkers might be associated with TBI-induced tauopathy. Future studies exploring the physiological relevance of OR TBI biomarkers in the normal brain and in the brain following TBI will provide a better understanding of the biological mechanisms underlying TBI and insights into novel therapeutic targets for TBI.
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Affiliation(s)
- Wei Zhao
- Department of Neurology, Mount Sinai School of Medicine, New York, NY, USA
| | - Lap Ho
- Department of Neurology, Mount Sinai School of Medicine, New York, NY, USA
| | - Merina Varghese
- Department of Neurology, Mount Sinai School of Medicine, New York, NY, USA
| | - Shrishailam Yemul
- Department of Neurology, Mount Sinai School of Medicine, New York, NY, USA.,GRECC, James J. Peters Veterans Affairs Medical Center, Bronx, NY, USA
| | | | - Wayne Gordon
- Department of Rehabilitation, Mount Sinai School of Medicine, New York, NY, USA
| | - Lindsay Knable
- Department of Neurology, Mount Sinai School of Medicine, New York, NY, USA
| | - Daniel Freire
- Department of Neurology, Mount Sinai School of Medicine, New York, NY, USA
| | - Vahram Haroutunian
- Department of Psychiatry, Mount Sinai School of Medicine, New York, NY, USA
| | - Giulio Maria Pasinetti
- Department of Neurology, Mount Sinai School of Medicine, New York, NY, USA.,Department of Psychiatry, Mount Sinai School of Medicine, New York, NY, USA.,GRECC, James J. Peters Veterans Affairs Medical Center, Bronx, NY, USA
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Loane DJ, Stoica BA, Byrnes KR, Jeong W, Faden AI. Activation of mGluR5 and inhibition of NADPH oxidase improves functional recovery after traumatic brain injury. J Neurotrauma 2013. [PMID: 23199080 DOI: 10.1089/neu.2012.2589] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Abstract Traumatic brain injury (TBI) induces microglial activation, which can contribute to secondary tissue loss. Activation of mGluR5 reduces microglial activation and inhibits microglial-mediated neurodegeneration in vitro, and is neuroprotective in experimental models of CNS injury. In vitro studies also suggest that the beneficial effects of mGluR5 activation involve nicotinamide adenine dinucleotide phosphate (NADPH) oxidase inhibition in activated microglia. We hypothesized that activation of mGluR5 by the selective agonist CHPG after TBI in mice is neuroprotective and that its therapeutic actions are mediated by NADPH oxidase inhibition. Vehicle, CHPG, or CHPG plus the mGluR5 antagonist (MPEP), were administered centrally, 30 minutes post-TBI, and functional recovery and lesion volume was assessed. CHPG significantly attenuated post-traumatic sensorimotor and cognitive deficits, and reduced lesion volumes; these effects were blocked by MPEP, thereby indicating neuroprotection involved selective activation of mGluR5. CHPG treatment also reduced NFκB activity and nitrite production in lipopolysaccharide-stimulated microglia and the protective effects of CHPG treatment were abrogated in NADPH oxidase deficient microglial cultures (gp91(phox-/-)). To address whether the neuroprotective effects of CHPG are mediated via the inhibition of NADPH oxidase, we administered the NADPH oxidase inhibitor apocynin with or without CHPG treatment after TBI. Both apocynin or CHPG treatment alone improved sensorimotor deficits and reduced lesion volumes when compared with vehicle-treated mice; however, the combined CHPG + apocynin treatment was not superior to CHPG alone. These data suggest that the neuroprotective effects of activating mGluR5 receptors after TBI are mediated, in part, via the inhibition of NADPH oxidase.
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Affiliation(s)
- David J Loane
- Department of Anesthesiology and Center for Shock, Trauma, and Anesthesiology Research (STAR), National Study Center for Trauma and EMS, University of Maryland School of Medicine, Baltimore, MD 21201, USA
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Maiese K, Chong ZZ, Wang S, Shang YC. Oxidant stress and signal transduction in the nervous system with the PI 3-K, Akt, and mTOR cascade. Int J Mol Sci 2012. [PMID: 23203037 PMCID: PMC3509553 DOI: 10.3390/ijms131113830] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Oxidative stress impacts multiple systems of the body and can lead to some of the most devastating consequences in the nervous system especially during aging. Both acute and chronic neurodegenerative disorders such as diabetes mellitus, cerebral ischemia, trauma, Alzheimer’s disease, Parkinson’s disease, Huntington’s disease, and tuberous sclerosis through programmed cell death pathways of apoptosis and autophagy can be the result of oxidant stress. Novel therapeutic avenues that focus upon the phosphoinositide 3-kinase (PI 3-K), Akt (protein kinase B), and the mammalian target of rapamycin (mTOR) cascade and related pathways offer exciting prospects to address the onset and potential reversal of neurodegenerative disorders. Effective clinical translation of these pathways into robust therapeutic strategies requires intimate knowledge of the complexity of these pathways and the ability of this cascade to influence biological outcome that can vary among disorders of the nervous system.
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Affiliation(s)
- Kenneth Maiese
- Laboratory of Cellular and Molecular Signaling, Newark, NJ 07101, USA; E-Mails: (Z.Z.C.); (S.W.); (Y.C.S.)
- Cancer Institute of New Jersey, New Brunswick, NJ 08903, USA
- New Jersey Health Sciences University, 205 South Orange Avenue, Newark, NJ 07101, USA
- Author to whom correspondence should be addressed: E-Mail:
| | - Zhao Zhong Chong
- Laboratory of Cellular and Molecular Signaling, Newark, NJ 07101, USA; E-Mails: (Z.Z.C.); (S.W.); (Y.C.S.)
- New Jersey Health Sciences University, 205 South Orange Avenue, Newark, NJ 07101, USA
| | - Shaohui Wang
- Laboratory of Cellular and Molecular Signaling, Newark, NJ 07101, USA; E-Mails: (Z.Z.C.); (S.W.); (Y.C.S.)
- New Jersey Health Sciences University, 205 South Orange Avenue, Newark, NJ 07101, USA
| | - Yan Chen Shang
- Laboratory of Cellular and Molecular Signaling, Newark, NJ 07101, USA; E-Mails: (Z.Z.C.); (S.W.); (Y.C.S.)
- New Jersey Health Sciences University, 205 South Orange Avenue, Newark, NJ 07101, USA
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Maiese K, Chong ZZ, Shang YC, Wang S. Erythropoietin: new directions for the nervous system. Int J Mol Sci 2012; 13:11102-11129. [PMID: 23109841 PMCID: PMC3472733 DOI: 10.3390/ijms130911102] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2012] [Revised: 08/16/2012] [Accepted: 08/30/2012] [Indexed: 12/14/2022] Open
Abstract
New treatment strategies with erythropoietin (EPO) offer exciting opportunities to prevent the onset and progression of neurodegenerative disorders that currently lack effective therapy and can progress to devastating disability in patients. EPO and its receptor are present in multiple systems of the body and can impact disease progression in the nervous, vascular, and immune systems that ultimately affect disorders such as Alzheimer's disease, Parkinson's disease, retinal injury, stroke, and demyelinating disease. EPO relies upon wingless signaling with Wnt1 and an intimate relationship with the pathways of phosphoinositide 3-kinase (PI 3-K), protein kinase B (Akt), and mammalian target of rapamycin (mTOR). Modulation of these pathways by EPO can govern the apoptotic cascade to control β-catenin, glycogen synthase kinase-3β, mitochondrial permeability, cytochrome c release, and caspase activation. Yet, EPO and each of these downstream pathways require precise biological modulation to avert complications associated with the vascular system, tumorigenesis, and progression of nervous system disorders. Further understanding of the intimate and complex relationship of EPO and the signaling pathways of Wnt, PI 3-K, Akt, and mTOR are critical for the effective clinical translation of these cell pathways into robust treatments for neurodegenerative disorders.
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Affiliation(s)
- Kenneth Maiese
- Laboratory of Cellular and Molecular Signaling, Cancer Center, F 1220, New Jersey Health Sciences University, 205 South Orange Avenue, Newark, NJ 07101, USA; E-Mails: (Z.Z.C.); (Y.C.S.); (S.W.)
- Cancer Institute of New Jersey, New Brunswick, New Jersey 08901, USA
- New Jersey Health Sciences University, Newark, New Jersey 07101, USA
| | - Zhao Zhong Chong
- Laboratory of Cellular and Molecular Signaling, Cancer Center, F 1220, New Jersey Health Sciences University, 205 South Orange Avenue, Newark, NJ 07101, USA; E-Mails: (Z.Z.C.); (Y.C.S.); (S.W.)
- New Jersey Health Sciences University, Newark, New Jersey 07101, USA
| | - Yan Chen Shang
- Laboratory of Cellular and Molecular Signaling, Cancer Center, F 1220, New Jersey Health Sciences University, 205 South Orange Avenue, Newark, NJ 07101, USA; E-Mails: (Z.Z.C.); (Y.C.S.); (S.W.)
- New Jersey Health Sciences University, Newark, New Jersey 07101, USA
| | - Shaohui Wang
- Laboratory of Cellular and Molecular Signaling, Cancer Center, F 1220, New Jersey Health Sciences University, 205 South Orange Avenue, Newark, NJ 07101, USA; E-Mails: (Z.Z.C.); (Y.C.S.); (S.W.)
- New Jersey Health Sciences University, Newark, New Jersey 07101, USA
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Wang JW, Wang HD, Zhong WZ, Li N, Cong ZX. Expression and cell distribution of metabotropic glutamate receptor 5 in the rat cortex following traumatic brain injury. Brain Res 2012; 1464:73-81. [DOI: 10.1016/j.brainres.2012.05.014] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2012] [Revised: 04/22/2012] [Accepted: 05/06/2012] [Indexed: 01/20/2023]
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Shah A, Silverstein PS, Singh DP, Kumar A. Involvement of metabotropic glutamate receptor 5, AKT/PI3K signaling and NF-κB pathway in methamphetamine-mediated increase in IL-6 and IL-8 expression in astrocytes. J Neuroinflammation 2012; 9:52. [PMID: 22420994 PMCID: PMC3338363 DOI: 10.1186/1742-2094-9-52] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2012] [Accepted: 03/15/2012] [Indexed: 01/12/2023] Open
Abstract
Methamphetamine (MA) is one of the commonly used illicit drugs and the central nervous system toxicity of MA is well documented. The mechanisms contributing to this toxicity have not been fully elucidated. In this study, we investigated the effect of MA on the expression levels of the proinflammatory cytokines/chemokines, IL-6 and IL-8 in an astrocytic cell line. The IL-6 and IL-8 RNA levels were found to increase by 4.6 ± 0.2 fold and 3.5 ± 0.2 fold, respectively, after exposure to MA for three days. Exposure of astrocytes to MA for 24 hours also caused increased expression of IL-6 and IL-8 at the level of both RNA and protein. The potential involvement of the nuclear factor-Kappa B (NF-κB) pathway was explored as one of the possible mechanism(s) responsible for the increased induction of IL-6 and IL-8 by MA. The MA-mediated increases in IL-6 and IL-8 were significantly abrogated by SC514. We also found that exposure of astrocytes to MA results in activation of NF-κB through the phosphorylation of IκB-α, followed by translocation of active NF-κB from the cytoplasm to the nucleus. In addition, treatment of cells with a specific inhibitor of metabotropic glutamate receptor-5 (mGluR5) revealed that MA-mediated expression levels of IL-6 and IL-8 were abrogated by this treatment by 42.6 ± 5.8% and 65.5 ± 3.5%, respectively. Also, LY294002, an inhibitor of the Akt/PI3K pathway, abrogated the MA-mediated induction of IL-6 and IL-8 by 77.9 ± 6.6% and 81.4 ± 2.6%, respectively. Thus, our study demonstrates the involvement of an NF-κB-mediated signaling mechanism in the induction of IL-6 and IL-8 by MA. Furthermore, we showed that blockade of mGluR5 can protect astrocytes from MA-mediated increases of proinflammatory cytokines/chemokines suggesting mGluR5 as a potential therapeutic target in treating MA-mediated neurotoxicity.
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Affiliation(s)
- Ankit Shah
- Division of Pharmacology, UMKC-School of Pharmacy, Kansas City, MO 64108, USA
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