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Zheng X, Yang J, Hou Y, Shi X, Liu K. Prediction of clinical progression in nervous system diseases: plasma glial fibrillary acidic protein (GFAP). Eur J Med Res 2024; 29:51. [PMID: 38216970 PMCID: PMC10785482 DOI: 10.1186/s40001-023-01631-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2023] [Accepted: 12/29/2023] [Indexed: 01/14/2024] Open
Abstract
Glial fibrillary acidic protein (GFAP), an intracellular type III intermediate filament protein, provides structural support and maintains the mechanical integrity of astrocytes. It is predominantly found in the astrocytes which are the most abundant subtypes of glial cells in the brain and spinal cord. As a marker protein of astrocytes, GFAP may exert a variety of physiological effects in neurological diseases. For example, previous published literatures showed that autoimmune GFAP astrocytopathy is an inflammatory disease of the central nervous system (CNS). Moreover, the studies of GFAP in brain tumors mainly focus on the predictive value of tumor volume. Furthermore, using biomarkers in the early setting will lead to a simplified and standardized way to estimate the poor outcome in traumatic brain injury (TBI) and ischemic stroke. Recently, observational studies revealed that cerebrospinal fluid (CSF) GFAP, as a valuable potential diagnostic biomarker for neurosyphilis, had a sensitivity of 76.60% and specificity of 85.56%. The reason plasma GFAP could serve as a promising biomarker for diagnosis and prediction of Alzheimer's disease (AD) is that it effectively distinguished AD dementia from multiple neurodegenerative diseases and predicted the individual risk of AD progression. In addition, GFAP can be helpful in differentiating relapsing-remitting multiple sclerosis (RRMS) versus progressive MS (PMS). This review article aims to provide an overview of GFAP in the prediction of clinical progression in neuroinflammation, brain tumors, TBI, ischemic stroke, genetic disorders, neurodegeneration and other diseases in the CNS and to explore the potential therapeutic methods.
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Affiliation(s)
- Xiaoxiao Zheng
- Department of Neurology, Neuroscience Center, The First Hospital of Jilin University, Xinmin Street 1#, Changchun, China
| | - Jingyao Yang
- Institute of Physiology, School of Basic Medical Sciences, Shanxi Medical University, Taiyuan, China
| | - Yiwei Hou
- Department of Neurology, Neuroscience Center, The First Hospital of Jilin University, Xinmin Street 1#, Changchun, China
| | - Xinye Shi
- Department of Cardiology, Shanxi Yingkang Yisheng General Hospital, Renmin North Road 5188#, Yuncheng, China
| | - Kangding Liu
- Department of Neurology, Neuroscience Center, The First Hospital of Jilin University, Xinmin Street 1#, Changchun, China.
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De D, Mukherjee I, Guha S, Paidi RK, Chakrabarti S, Biswas SC, Bhattacharyya SN. Rheb-mTOR activation rescues Aβ-induced cognitive impairment and memory function by restoring miR-146 activity in glial cells. MOLECULAR THERAPY. NUCLEIC ACIDS 2021; 24:868-887. [PMID: 34094708 PMCID: PMC8141608 DOI: 10.1016/j.omtn.2021.04.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Accepted: 04/09/2021] [Indexed: 12/22/2022]
Abstract
Deposition of amyloid beta plaques in adult rat or human brain is associated with increased production of proinflammatory cytokines by associated glial cells that are responsible for degeneration of the diseased tissue. The expression of these cytokines is usually under check and is controlled at the post-transcriptional level via several microRNAs. Computational analysis of gene expression profiles of cortical regions of Alzheimer’s disease patients’ brain suggests ineffective target cytokine mRNA suppression by existing micro-ribonucleoproteins (miRNPs) in diseased brain. Exploring the mechanism of amyloid beta-induced cytokine expression, we have identified how the inactivation of the repressive miR-146 miRNPs causes increased production of cytokines in amyloid beta-exposed glial cells. In exploration of the cause of miRNP inactivation, we have noted amyloid beta oligomer-induced sequestration of the mTORC1 complex to early endosomes that results in decreased Ago2 phosphorylation, limited Ago2-miRNA uncoupling, and retarded Ago2-cytokine mRNA interaction in rat astrocytes. Interestingly, constitutive activation of mTORC1 by Rheb activator restricts proinflammatory cytokine production by reactivating miR-146 miRNPs in amyloid beta-exposed glial cells to rescue the disease phenotype in the in vivo rat model of Alzheimer’s disease.
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Affiliation(s)
- Dipayan De
- RNA Biology Research Laboratory, Molecular Genetics Division, CSIR-Indian Institute of Chemical Biology, Kolkata 700032, India
| | - Ishita Mukherjee
- Structural Biology and Bio-informatics Division, CSIR-Indian Institute of Chemical Biology, Kolkata 700032, India
| | - Subhalakshmi Guha
- Cell Biology and Physiology Division, CSIR-Indian Institute of Chemical Biology, Kolkata 700032, India
| | - Ramesh Kumar Paidi
- Cell Biology and Physiology Division, CSIR-Indian Institute of Chemical Biology, Kolkata 700032, India
| | - Saikat Chakrabarti
- Structural Biology and Bio-informatics Division, CSIR-Indian Institute of Chemical Biology, Kolkata 700032, India
| | - Subhas C Biswas
- Cell Biology and Physiology Division, CSIR-Indian Institute of Chemical Biology, Kolkata 700032, India
| | - Suvendra N Bhattacharyya
- RNA Biology Research Laboratory, Molecular Genetics Division, CSIR-Indian Institute of Chemical Biology, Kolkata 700032, India
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Dolenec P, Pilipović K, Janković T, Župan G. Pattern of Neuronal and Axonal Damage, Glial Response, and Synaptic Changes in Rat Cerebellum within the First Week following Traumatic Brain Injury. J Neuropathol Exp Neurol 2021; 79:1163-1182. [PMID: 33057716 DOI: 10.1093/jnen/nlaa111] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
We examined damage and repair processes in the rat cerebellum within the first week following moderate traumatic brain injury (TBI) induced by lateral fluid percussion injury (LFPI) over the left parietal cortex. Rats were killed 1, 3, or 7 days after the injury or sham procedure. Fluoro-Jade B staining revealed 2 phases of neurodegenerative changes in the cell bodies and fibers: first, more focal, 1 day after the LFPI, and second, widespread, starting on post-injury day 3. Purkinje cell loss was detected in posterior lobule IX 1 day following LFPI. Apoptosis was observed in the cerebellar cortex, on days 1 and 7 following LFPI, and was not caspase- or apoptosis-inducing factor (AIF)-mediated. AIF immunostaining indicated axonal damage in the cerebellar white matter tracts 3- and 7-days post-injury. Significant astrocytosis and microgliosis were noticed on day 7 following LFPI at the sites of neuronal damage and loss. Immunohistochemical labeling with the presynaptic markers synaptophysin and growth-associated protein-43 revealed synaptic perturbations already on day 1 that were more pronounced at later time points following LFPI. These results provide new insights into pathophysiological alterations in the cerebellum and their mechanisms following cerebral TBI.
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Affiliation(s)
- Petra Dolenec
- Department of Pharmacology, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
| | - Kristina Pilipović
- Department of Pharmacology, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
| | - Tamara Janković
- Department of Pharmacology, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
| | - Gordana Župan
- Department of Pharmacology, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
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Kim JE, Kang TC. PKC, AKT and ERK1/2-Mediated Modulations of PARP1, NF-κB and PEA15 Activities Distinctly Regulate Regional Specific Astroglial Responses Following Status Epilepticus. Front Mol Neurosci 2019; 12:180. [PMID: 31396050 PMCID: PMC6667551 DOI: 10.3389/fnmol.2019.00180] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Accepted: 07/09/2019] [Indexed: 01/04/2023] Open
Abstract
Status epilepticus (SE, a prolonged seizure activity) leads to reactive astrogliosis and astroglial apoptosis in the regional specific manners, independent of hemodynamics. Poly(ADP-ribose) polymerase-1 (PARP1) activity is relevant to these distinct astroglial responses. Since various regulatory signaling molecules beyond PARP1 activity may be involved in the distinct astroglial response to SE, it is noteworthy to explore the roles of protein kinases in PARP1-mediated reactive astrogliosis and astroglial apoptosis following SE, albeit at a lesser extent. In the present study, inhibitions of protein kinase C (PKC), AKT and extracellular signal-related kinases 1/2 (ERK1/2), but not calcium/calmodulin-dependent protein kinase II (CaMKII), attenuated CA1 reactive astrogliosis accompanied by reducing PARP1 activity following SE, respectively. However, inhibition of AKT and ERK1/2 deteriorated SE-induced dentate astroglial loss concomitant with the diminished PARP1 activity. Following SE, PKC- and AKT inhibitors diminished phosphoprotein enriched in astrocytes of 15 kDa (PEA15)-S104 and -S116 phosphorylations in CA1 astrocytes, but not in dentate astrocytes, respectively. Inhibitors of PKC, AKT and ERK1/2 also abrogated SE-induced nuclear factor-κB (NF-κB)-S311 and -S468 phosphorylations in CA1 astrocytes. In contrast, both AKT and ERK1/2 inhibitors enhanced NF-κB-S468 phosphorylation in dentate astrocytes. Furthermore, PARP1 inhibitor aggravated dentate astroglial loss following SE. AKT inhibition deteriorated dentate astroglial loss and led to CA1 astroglial apoptosis following SE, which were ameliorated by AKT activation. These findings suggest that activities of PARP1, PEA15 and NF-κB may be distinctly regulated by PKC, AKT and ERK1/2, which may be involved in regional specific astroglial responses following SE.
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Affiliation(s)
- Ji-Eun Kim
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University, Chuncheon, South Korea
| | - Tae-Cheon Kang
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University, Chuncheon, South Korea
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Dai Q, Li S, Liu T, Zheng J, Han S, Qu A, Li J. Interleukin-17A-mediated alleviation of cortical astrocyte ischemic injuries affected the neurological outcome of mice with ischemic stroke. J Cell Biochem 2019; 120:11498-11509. [PMID: 30746745 DOI: 10.1002/jcb.28429] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Revised: 11/22/2018] [Accepted: 11/29/2018] [Indexed: 01/24/2023]
Abstract
We previously reported that astrocytes are the main sources of interleukin (IL)-17A production that could aggravate neuronal injuries in ischemic stroke. However, the effects of IL-17A on ischemic astrocytes themselves and the underlying molecular mechanism are still unclear. In this study, we found that recombinant mouse (rm) IL-17A could significantly (P < 0.05 or <0.001) alleviate 1-hour oxygen-glucose deprivation (OGD)/reoxygenation (R) 24-hour-induced ischemic injuries in cortical astrocytes with a dose-dependent manner (n = 6 per group). The Western blot and cell cycle analysis results revealed that rmIL-17A significantly ( P < 0.05) inhibited procaspase-3 cleavage without affecting cell proliferation in 1-hour OGD/R 24-hour-treated cortical astrocytes (n = 6 per group). Among the five IL-17 receptor subunits (IL-RA, -RB, -RC, -RD, and -RE), only IL-17RA ( P < 0.01) and -17RC ( P < 0.05) membrane translocation (not messenger RNA and protein) levels were downregulated in cortical astrocytes following 1-hour OGD/reperfusion 24 hours, and rmIL-17A could significantly ( P < 0.05 or <0.001) inhibit this downregulation (n = 6 per group). To further verify the impact of IL-17A on the neurological outcome of ischemic stroke, we found that the intracerebroventricular injection of IL-17A neutralizing monoclonal antibody remarkably ( P < 0.001) reduced the astrocyte activation and improve neurological function ( P < 0.05 or <0.01) of mice following 1-hour middle cerebral artery occlusion/reperfusion (R) 3 to 7 days (n = 6 or 8 per group). These results suggested that IL-17A-mediated alleviation of cortical astrocyte ischemic injuries could affect the neurological outcome of mice with ischemic stroke, which might be mainly dependent on the cell apoptosis pathway through inhibiting the downregulation of IL-17RA and -17RC membrane translocations.
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Affiliation(s)
- Qingqing Dai
- Department of Neurobiology and Center of Stroke, Beijing Institute for Brain Disorders, School of Basic Medical Science, Capital Medical University, Beijing, China
| | - Shujuan Li
- Department of Neurology, Beijing Chao-Yang Hospital, Capital Medical University, Beijing, China
| | - Ting Liu
- Department of Neurobiology and Center of Stroke, Beijing Institute for Brain Disorders, School of Basic Medical Science, Capital Medical University, Beijing, China
| | - Jiayin Zheng
- Department of Neurobiology and Center of Stroke, Beijing Institute for Brain Disorders, School of Basic Medical Science, Capital Medical University, Beijing, China
| | - Song Han
- Department of Neurobiology and Center of Stroke, Beijing Institute for Brain Disorders, School of Basic Medical Science, Capital Medical University, Beijing, China
| | - Aijuan Qu
- Department of Physiology and Pathophysiology, School of Basic Medical Science, Capital Medical University, Beijing, China
| | - Junfa Li
- Department of Neurobiology and Center of Stroke, Beijing Institute for Brain Disorders, School of Basic Medical Science, Capital Medical University, Beijing, China
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Kim JE, Kang TC. Nucleocytoplasmic p27 Kip1 Export Is Required for ERK1/2-Mediated Reactive Astroglial Proliferation Following Status Epilepticus. Front Cell Neurosci 2018; 12:152. [PMID: 29930499 PMCID: PMC5999727 DOI: 10.3389/fncel.2018.00152] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Accepted: 05/16/2018] [Indexed: 01/09/2023] Open
Abstract
Reactive astrogliosis is a prominent and ubiquitous reaction of astrocytes to many types of brain injury. Up-regulation of glial fibrillary acidic protein (GFAP) expression and astroglial proliferation are hallmarks of reactive astrogliosis. However, the mechanisms that regulate reactive astrogliosis remain elusive. In the present study, status epilepticus (SE, a prolonged seizure activity) led to reactive astrogliosis showing the increases in GFAP expression and the number of proliferating astrocytes with prolonged extracellular signal receptor-activated kinases 1/2 (ERK1/2) activation and reduced nuclear p27Kip1 level. U0126, an ERK1/2 inhibitor, showed opposite effects. Leptomycin B (LMB), an inhibitor of chromosomal maintenance 1 (CRM1), attenuated nucleocytoplasmic p27Kip1 export and astroglial proliferation, although it up-regulated ERK1/2 phosphorylation and GFAP expression. Roscovitine ameliorated the reduced nuclear p27Kip1 level and astroglial proliferation without changing GFAP expression and ERK1/2 phosphorylation. U0126 aggravated SE-induced astroglial apoptosis in the molecular layer of the dentate gyrus that was unaffected by LMB and roscovitine. In addition, U0126 exacerbated SE-induced neuronal death, while LMB mitigated it. Roscovitine did not affect SE-induced neuronal death. The present data elucidate for the first time the roles of nucleocytoplasmic p27Kip1 transport in ERK1/2-mediated reactive astrogliosis independent of SE-induced neuronal death and astroglial apoptosis. Therefore, our findings suggest that nucleocytoplasmic p27Kip1 export may be required for ERK1/2-mediated astroglial proliferation during reactive astrogliosis, and that nuclear p27Kip1 entrapment may be a potential therapeutic strategy for anti-proliferation in reactive astrocytes.
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Affiliation(s)
- Ji-Eun Kim
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University, Chuncheon, South Korea
| | - Tae-Cheon Kang
- Department of Anatomy and Neurobiology, Institute of Epilepsy Research, College of Medicine, Hallym University, Chuncheon, South Korea
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Wang N, Yao F, Li K, Zhang L, Yin G, Du M, Wu B. Fisetin regulates astrocyte migration and proliferation in vitro. Int J Mol Med 2017; 39:783-790. [PMID: 28204814 PMCID: PMC5360439 DOI: 10.3892/ijmm.2017.2890] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Accepted: 01/12/2017] [Indexed: 11/20/2022] Open
Abstract
Fisetin (3,3′,4′,7-tetrahydroxyflavone) is a plant flavonol found in fruits and vegetables that has been reported to inhibit migration and proliferation in several types of cancer. Reactive astrogliosis involves astrocyte migration and proliferation, and contributes to the formation of glial scars in central nervous system (CNS) disorders. However, the effect of fisetin on the migration and proliferation of astrocytes remains unclear. In this study, we found that fisetin inhibited astrocyte migration in a scratch-wound assay and diminished the phosphorylation of focal adhesion kinase (FAK; Tyr576/577 and paxillin (Tyr118). It also suppressed cell proliferation, as indicated by the decreased number of 5-ethynyl-2′-deoxyuridine (EdU)-positive cells, induced cell cycle arrest in the G1 phase, reduced the percentage of cells in the G2 and S phase (as measured by flow cytometry), and decreased cyclin D1 expression, but had no effect on apoptosis. Fisetin also decreased the phosphorylation levels of Akt and extracellular signal-regulated kinase (Erk)1/2, but had no effect on the phosphorylation of p38 mitogen-activated protein kinase (MAPK). These results indicate that fisetin inhibits aggressive cell phenotypes by suppressing cell migration and proliferation via the Akt/Erk signaling pathway. Fisetin may thus have potential for use as a therapeutic strategy targeting reactive astrocytes, which may lead to the inhibition of glial scar formation in vitro.
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Affiliation(s)
- Nan Wang
- Research Center of Clinical Medicine, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong 510515, P.R. China
| | - Fang Yao
- Research Center of Clinical Medicine, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong 510515, P.R. China
| | - Ke Li
- Research Center of Clinical Medicine, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong 510515, P.R. China
| | - Lanlan Zhang
- Research Center of Clinical Medicine, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong 510515, P.R. China
| | - Guo Yin
- Research Center of Clinical Medicine, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong 510515, P.R. China
| | - Mingjun Du
- Research Center of Clinical Medicine, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong 510515, P.R. China
| | - Bingyi Wu
- Research Center of Clinical Medicine, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong 510515, P.R. China
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Relationship Between Obesity, Alzheimer’s Disease, and Parkinson’s Disease: an Astrocentric View. Mol Neurobiol 2016; 54:7096-7115. [DOI: 10.1007/s12035-016-0193-8] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Accepted: 10/03/2016] [Indexed: 12/13/2022]
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Zhang Z, Bassam B, Thomas AG, Williams M, Liu J, Nance E, Rojas C, Slusher BS, Kannan S. Maternal inflammation leads to impaired glutamate homeostasis and up-regulation of glutamate carboxypeptidase II in activated microglia in the fetal/newborn rabbit brain. Neurobiol Dis 2016; 94:116-28. [PMID: 27326668 PMCID: PMC5394739 DOI: 10.1016/j.nbd.2016.06.010] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Revised: 06/05/2016] [Accepted: 06/16/2016] [Indexed: 12/12/2022] Open
Abstract
Astrocyte dysfunction and excessive activation of glutamatergic systems have been implicated in a number of neurologic disorders, including periventricular leukomalacia (PVL) and cerebral palsy (CP). However, the role of chorioamnionitis on glutamate homeostasis in the fetal and neonatal brains is not clearly understood. We have previously shown that intrauterine endotoxin administration results in intense microglial 'activation' and increased pro-inflammatory cytokines in the periventricular region (PVR) of the neonatal rabbit brain. In this study, we assessed the effect of maternal inflammation on key components of the glutamate pathway and its relationship to astrocyte and microglial activation in the fetal and neonatal New Zealand white rabbit brain. We found that intrauterine endotoxin exposure at gestational day 28 (G28) induced acute and prolonged glutamate elevation in the PVR of fetal (G29, 1day post-injury) and postnatal day 1 (PND1, 3days post-injury) brains along with prominent morphological changes in the astrocytes (soma hypertrophy and retracted processes) in the white matter tracts. There was a significant increase in glutaminase and N-Methyl-d-Aspartate receptor (NMDAR) NR2 subunit expression along with decreased glial L-glutamate transporter 1 (GLT-1) in the PVR at G29, that would promote acute dysregulation of glutamate homeostasis. This was accompanied with significantly decreased TGF-β1 at PND1 in CP kits indicating ongoing neuroinflammation. We also show for the first time that glutamate carboxypeptidase II (GCPII) was significantly increased in the activated microglia at the periventricular white matter area in both G29 and PND1 CP kits. This was confirmed by in vitro studies demonstrating that LPS activated primary microglia markedly upregulate GCPII enzymatic activity. These results suggest that maternal intrauterine endotoxin exposure results in early onset and long-lasting dysregulation of glutamate homeostasis, which may be mediated by impaired astrocyte function and GCPII upregulation in activated microglia.
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Affiliation(s)
- Zhi Zhang
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins School of Medicine, 1800 Orleans St, Baltimore, MD 21287, USA
| | - Bassam Bassam
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins School of Medicine, 1800 Orleans St, Baltimore, MD 21287, USA
| | - Ajit G Thomas
- Johns Hopkins Drug Discovery, Johns Hopkins School of Medicine, 1800 Orleans St, Baltimore, MD 21287, USA
| | - Monica Williams
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins School of Medicine, 1800 Orleans St, Baltimore, MD 21287, USA
| | - Jinhuan Liu
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins School of Medicine, 1800 Orleans St, Baltimore, MD 21287, USA
| | - Elizabeth Nance
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins School of Medicine, 1800 Orleans St, Baltimore, MD 21287, USA
| | - Camilo Rojas
- Johns Hopkins Drug Discovery, Johns Hopkins School of Medicine, 1800 Orleans St, Baltimore, MD 21287, USA
| | - Barbara S Slusher
- Neurology, Johns Hopkins School of Medicine, 1800 Orleans St, Baltimore, MD 21287, USA; Johns Hopkins Drug Discovery, Johns Hopkins School of Medicine, 1800 Orleans St, Baltimore, MD 21287, USA
| | - Sujatha Kannan
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins School of Medicine, 1800 Orleans St, Baltimore, MD 21287, USA.
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Tetramethylpyrazine Ameliorates Rotenone-Induced Parkinson's Disease in Rats: Involvement of Its Anti-Inflammatory and Anti-Apoptotic Actions. Mol Neurobiol 2016; 54:4866-4878. [PMID: 27514753 DOI: 10.1007/s12035-016-0028-7] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2016] [Accepted: 08/01/2016] [Indexed: 12/21/2022]
Abstract
Parkinson's disease (PD) is a slowly progressive neurodegenerative movement disorder. Apoptosis, neuroinflammation, and oxidative stress are the current hypothesized mechanisms for PD pathogenesis. Tetramethylpyrazine (TMP), the major bioactive component of Ligusticum wallichii Franchat (ChuanXiong), Family Apiaceae, reportedly has anti-apoptotic, anti-inflammatory and antioxidant effects. This study investigated the role of 'TMP' in preventing rotenone-induced neurobiological and behavioral sequelae. A preliminary dose-response study was conducted where rats received TMP (10, 20, and 40 mg/kg, i.p.) concomitantly with rotenone (2 mg/kg, s.c.) for 4 weeks. Catalepsy, locomotor activity, striatal dopamine content, and tyrosine hydroxylase "TH" and α-synuclein immunoreactivity were evaluated. The selected TMP dose (20 mg/kg) was used for western blot analysis of Bax, Bcl2, and DJ-1, immunohistochemical detection of nuclear factor kappa B (NF-кB), inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX2), and glial fibrillary acidic protein (GFAP) expression, in addition to biochemical analysis of caspase-3 activity, nuclear factor erythroid 2-related factor 2 (Nrf2), and heme oxygenase-1 (HO-1) levels. Results showed that TMP (20 mg/kg) significantly improved midbrain and striatal TH expression and striatal dopamine content as well as the motor deficits, compared to rotenone-treated group. These results were correlated with reduction in caspase-3 activity and α-synuclein expression, along with improvement of midbrain and striatal Bax/Bcl2 ratio compared to rotenone-treated group. TMP also attenuated rotenone-induced upregulation of Nrf2/HO-1 pathway. Furthermore, TMP downregulated rotenone-induced neuroinflammation markers: NF-кB, iNOS, COX2, and GFAP expression in both the midbrain and striatum. Taken together, the current study suggests that TMP is entitled to, at least partially, preventing PD neurobiological and behavioral deficits by virtue of its anti-apoptotic, anti-inflammatory, and antioxidant actions.
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Oxidative stress upregulates zinc uptake activity via Zrt/Irt-like protein 1 (ZIP1) in cultured mouse astrocytes. Life Sci 2016; 151:305-312. [DOI: 10.1016/j.lfs.2016.03.025] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2015] [Revised: 03/09/2016] [Accepted: 03/11/2016] [Indexed: 11/22/2022]
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12
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Ayers-Ringler JR, Jia YF, Qiu YY, Choi DS. Role of astrocytic glutamate transporter in alcohol use disorder. World J Psychiatry 2016; 6:31-42. [PMID: 27014596 PMCID: PMC4804266 DOI: 10.5498/wjp.v6.i1.31] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2015] [Revised: 11/18/2015] [Accepted: 01/11/2016] [Indexed: 02/05/2023] Open
Abstract
Alcohol use disorder (AUD) is one of the most widespread neuropsychiatric conditions, having a significant health and socioeconomic impact. According to the 2014 World Health Organization global status report on alcohol and health, the harmful use of alcohol is responsible for 5.9% of all deaths worldwide. Additionally, 5.1% of the global burden of disease and injury is ascribed to alcohol (measured in disability adjusted life years, or disability adjusted life years). Although the neurobiological basis of AUD is highly complex, the corticostriatal circuit contributes significantly to the development of addictive behaviors. In-depth investigation into the changes of the neurotransmitters in this circuit, dopamine, gamma-aminobutyricacid, and glutamate, and their corresponding neuronal receptors in AUD and other addictions enable us to understand the molecular basis of AUD. However, these discoveries have also revealed a dearth of knowledge regarding contributions from non-neuronal sources. Astrocytes, though intimately involved in synaptic function, had until recently been noticeably overlooked in their potential role in AUD. One major function of the astrocyte is protecting neurons from excitotoxicity by removing glutamate from the synapse via excitatory amino acid transporter type 2. The importance of this key transporter in addiction, as well as ethanol withdrawal, has recently become evident, though its regulation is still under investigation. Historically, pharmacotherapy for AUD has been focused on altering the activity of neuronal glutamate receptors. However, recent clinical evidence has supported the animal-based findings, showing that regulating glutamate homeostasis contributes to successful management of recovery from AUD.
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Verkhratsky A, Matteoli M, Parpura V, Mothet JP, Zorec R. Astrocytes as secretory cells of the central nervous system: idiosyncrasies of vesicular secretion. EMBO J 2016; 35:239-57. [PMID: 26758544 DOI: 10.15252/embj.201592705] [Citation(s) in RCA: 285] [Impact Index Per Article: 35.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Accepted: 12/01/2015] [Indexed: 11/09/2022] Open
Abstract
Astrocytes are housekeepers of the central nervous system (CNS) and are important for CNS development, homeostasis and defence. They communicate with neurones and other glial cells through the release of signalling molecules. Astrocytes secrete a wide array of classic neurotransmitters, neuromodulators and hormones, as well as metabolic, trophic and plastic factors, all of which contribute to the gliocrine system. The release of neuroactive substances from astrocytes occurs through several distinct pathways that include diffusion through plasmalemmal channels, translocation by multiple transporters and regulated exocytosis. As in other eukaryotic cells, exocytotic secretion from astrocytes involves divergent secretory organelles (synaptic-like microvesicles, dense-core vesicles, lysosomes, exosomes and ectosomes), which differ in size, origin, cargo, membrane composition, dynamics and functions. In this review, we summarize the features and functions of secretory organelles in astrocytes. We focus on the biogenesis and trafficking of secretory organelles and on the regulation of the exocytotic secretory system in the context of healthy and diseased astrocytes.
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Affiliation(s)
- Alexei Verkhratsky
- Faculty of Life Sciences, The University of Manchester, Manchester, UK Achucarro Center for Neuroscience, IKERBASQUE Basque Foundation for Science, Bilbao, Spain Department of Neurosciences, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain University of Nizhny Novgorod, Nizhny Novgorod, Russia Laboratory of Neuroendocrinology-Molecular Cell Physiology, Faculty of Medicine, Institute of Pathophysiology University of Ljubljana, Ljubljana, Slovenia Celica BIOMEDICAL, Ljubljana, Slovenia
| | - Michela Matteoli
- CNR Institute of Neuroscience, Milano, Italy Humanitas Research Hospital, Rozzano, Italy
| | - Vladimir Parpura
- Department of Neurobiology, Civitan International Research Center and Center for Glial Biology in Medicine, Evelyn F. McKnight Brain Institute, Atomic Force Microscopy & Nanotechnology Laboratories University of Alabama at Birmingham, Birmingham, AL, USA
| | - Jean-Pierre Mothet
- Team Gliotransmission & Synaptopathies, Aix-Marseille University CNRS, CRN2M UMR7286, Marseille, France
| | - Robert Zorec
- Laboratory of Neuroendocrinology-Molecular Cell Physiology, Faculty of Medicine, Institute of Pathophysiology University of Ljubljana, Ljubljana, Slovenia Celica BIOMEDICAL, Ljubljana, Slovenia
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14
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Ergul A, Valenzuela JP, Fouda AY, Fagan SC. Cellular connections, microenvironment and brain angiogenesis in diabetes: Lost communication signals in the post-stroke period. Brain Res 2015; 1623:81-96. [PMID: 25749094 PMCID: PMC4743654 DOI: 10.1016/j.brainres.2015.02.045] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Revised: 02/18/2015] [Accepted: 02/23/2015] [Indexed: 12/16/2022]
Abstract
Diabetes not only increases the risk but also worsens the motor and cognitive recovery after stroke, which is the leading cause of disability worldwide. Repair after stroke requires coordinated communication among various cell types in the central nervous system as well as circulating cells. Vascular restoration is critical for the enhancement of neurogenesis and neuroplasticity. Given that vascular disease is a major component of all complications associated with diabetes including stroke, this review will focus on cellular communications that are important for vascular restoration in the context of diabetes. This article is part of a Special Issue entitled SI: Cell Interactions In Stroke.
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Affiliation(s)
- Adviye Ergul
- Charlie Norwood Veterans Affairs Medical Center, Augusta, GA 30904, USA; Department of Physiology, Medical College of Georgia, Georgia Regents University, 1120 15th Street, CA 2094, Augusta, GA 30912, USA; Program in Clinical and Experimental Therapeutics, College of Pharmacy, University of Georgia, Augusta, GA 30912, USA.
| | - John Paul Valenzuela
- Department of Physiology, Medical College of Georgia, Georgia Regents University, 1120 15th Street, CA 2094, Augusta, GA 30912, USA
| | - Abdelrahman Y Fouda
- Charlie Norwood Veterans Affairs Medical Center, Augusta, GA 30904, USA; Program in Clinical and Experimental Therapeutics, College of Pharmacy, University of Georgia, Augusta, GA 30912, USA
| | - Susan C Fagan
- Charlie Norwood Veterans Affairs Medical Center, Augusta, GA 30904, USA; Department of Neurology, Medical College of Georgia, Georgia Regents University, Augusta, GA 30912, USA; Program in Clinical and Experimental Therapeutics, College of Pharmacy, University of Georgia, Augusta, GA 30912, USA
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15
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Pan HC, Chou YC, Sun SH. P2X7 R-mediated Ca(2+) -independent d-serine release via pannexin-1 of the P2X7 R-pannexin-1 complex in astrocytes. Glia 2015; 63:877-93. [PMID: 25630251 DOI: 10.1002/glia.22790] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Accepted: 12/30/2014] [Indexed: 12/14/2022]
Abstract
D-serine is a coagonist of N-methyl-d-aspartate (NMDA) subtype of glutamate receptor and plays a role in regulating activity-dependent synaptic plasticity. In this study, we examined the mechanism by which extracellular ATP triggers the release of d-serine from astrocytes and discovered a novel Ca(2+) -independent release mechanism mediated by P2X7 receptors (P2X7 R). Using [(3) H] d-serine, which was loaded into astrocytes via the neutral amino acid transporter 2 (ASCT2), we observed that ATP and a potent P2X7 R agonist, 2'(3')-O-(4-benzoylbenzoyl)adenosine-5'-triphosphate (BzATP), stimulated [(3) H]D-serine release and that were abolished by P2X7 R selective antagonists and by shRNAs, whereas enhanced by removal of intracellular or extracellular Ca(2+) . The P2X7 R-mediated d-serine release was inhibited by pannexin-1 antagonists, such as carbenoxolone (CBX), probenecid (PBN), and (10) Panx-1 peptide, and shRNAs, and stimulation of P2X7 R induced P2X7 R-pannexin-1 complex formation. Simply incubating astrocytes in Ca(2+) /Mg(2+) -free buffer also induced the complex formation, and that enhanced basal d-serine release through pannexin-1. The P2X7 R-mediated d-serine release assayed in Ca(2+) /Mg(2+) -free buffer was enhanced as well, and that was inhibited by CBX. Treating astrocytes with general protein kinase C (PKC) inhibitors, such as chelerythrine, GF109203X, and staurosporine, but not Ca(2+) -dependent PKC inhibitor, Gö6976, inhibited the P2X7 R-mediated d-serine release. Thus, we conclude that in astrocytes, P2X7 R-pannexin-1 complex formation is crucial for P2X7 R-mediated d-serine release through pannexin-1 hemichannel. The release is Ca(2+) -independent and regulates by a Ca(2+) -independent PKC. The activated P2X7 R per se is also functioned as a permeation channel to release d-serine in part. This P2X7 R-mediated d-serine release represents an important mechanism for activity-dependent neuron-glia interaction.
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Affiliation(s)
- Han-Chi Pan
- Institute of Neuroscience, National Yang-Ming University, Taipei, Taiwan
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16
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Liu Z, Li Y, Cui Y, Roberts C, Lu M, Wilhelmsson U, Pekny M, Chopp M. Beneficial effects of gfap/vimentin reactive astrocytes for axonal remodeling and motor behavioral recovery in mice after stroke. Glia 2014; 62:2022-33. [PMID: 25043249 DOI: 10.1002/glia.22723] [Citation(s) in RCA: 146] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Revised: 06/25/2014] [Accepted: 07/03/2014] [Indexed: 12/12/2022]
Abstract
The functional role of reactive astrocytes after stroke is controversial. To elucidate whether reactive astrocytes contribute to neurological recovery, we compared behavioral outcome, axonal remodeling of the corticospinal tract (CST), and the spatio-temporal change of chondroitin sulfate proteoglycan (CSPG) expression between wild-type (WT) and glial fibrillary acidic protein/vimentin double knockout (GFAP(-/-) Vim(-/-) ) mice subjected to Rose Bengal induced cerebral cortical photothrombotic stroke in the right forelimb motor area. A foot-fault test and a single pellet reaching test were performed prior to and on day 3 after stroke, and weekly thereafter to monitor functional deficit and recovery. Biotinylated dextran amine (BDA) was injected into the left motor cortex to anterogradely label the CST axons. Compared with WT mice, the motor functional recovery and BDA-positive CST axonal length in the denervated side of the cervical gray matter were significantly reduced in GFAP(-/-) Vim(-/-) mice (n = 10/group, P < 0.01). Immunohistological data showed that in GFAP(-/-) Vim(-/-) mice, in which astrocytic reactivity is attenuated, CSPG expression was significantly increased in the lesion remote areas in both hemispheres, but decreased in the ischemic lesion boundary zone, compared with WT mice (n = 12/group, P < 0.001). Our data suggest that attenuated astrocytic reactivity impairs or delays neurological recovery by reducing CST axonal remodeling in the denervated spinal cord. Thus, manipulation of astrocytic reactivity post stroke may represent a therapeutic target for neurorestorative strategies.
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Affiliation(s)
- Zhongwu Liu
- Department of Neurology, Henry Ford Hospital, Detroit, Michigan
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17
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Arndt DL, Arnold JC, Cain ME. The effects of mGluR2/3 activation on acute and repeated amphetamine-induced locomotor activity in differentially reared male rats. Exp Clin Psychopharmacol 2014; 22:257-65. [PMID: 24467371 PMCID: PMC4041831 DOI: 10.1037/a0035273] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Environmental stimuli play a key role in affecting the likelihood to abuse drugs. Environmental enrichment can reduce that likelihood. The neurotransmitter glutamate contributes to both drug reward and rearing-induced changes in the brain. The current study investigated the effects of the Group-2 metabotropic glutamate receptor (mGluR2/3) agonist, LY-379268 (0.5, 1.0 mg/kg), on acute and repeated amphetamine-induced locomotor activity in differentially reared male rats. Male Sprague-Dawley rats were randomly assigned to one of 3 environmental conditions postweaning: enriched (EC), isolated (IC), or standard (SC), where they reared for 30 days. The effect of LY-379268 on acute amphetamine-induced locomotor activity was assessed. Rats were injected with either LY-379268 (0.5, 1.0 mg/kg) or saline prior to an amphetamine (0.5 mg/kg) or saline challenge injection. Rats were also administered amphetamine (0.5 mg/kg) or saline injections prior to 5 locomotor sessions. Following a rest period of 14-15 days, the effects of repeated amphetamine exposure were evaluated using LY-379268 (0.5, 1.0 mg/kg) or saline injections 30 min prior to receiving amphetamine (0.5 mg/kg). Results showed that LY-379268 administration dose-dependently attenuated acute amphetamine-induced locomotor activity, with EC rats generally displaying less attenuation than IC or SC rats. After repeated amphetamine administrations, the ability of LY-379268 to attenuate the final expression of amphetamine-induced locomotor activity in differentially reared rats was dose-dependent. The differing effect of LY-379268 observed in EC rats suggests enrichment-induced glutamatergic alterations that may protect against sensitivity to psychostimulants.
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18
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Li Y, Liu Z, Xin H, Chopp M. The role of astrocytes in mediating exogenous cell-based restorative therapy for stroke. Glia 2013; 62:1-16. [PMID: 24272702 DOI: 10.1002/glia.22585] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2013] [Revised: 08/08/2013] [Accepted: 09/18/2013] [Indexed: 12/19/2022]
Abstract
Astrocytes have not been a major therapeutic target for the treatment of stroke, with most research emphasis on the neuron. Given the essential role that astrocytes play in maintaining physiological function of the central nervous system and the very rapid and sensitive reaction astrocytes have in response to cerebral injury or ischemic insult, we propose to replace the neurocentric view for treatment with a more nuanced astrocytic centered approach. In addition, after decades of effort in attempting to develop neuroprotective therapies, which target reduction of the ischemic lesion, there are no effective clinical treatments for stroke, aside from thrombolysis with tissue plasminogen activator, which is used in a small minority of patients. A more promising therapeutic approach, which may affect nearly all stroke patients, may be in promoting endogenous restorative mechanisms, which enhance neurological recovery. A focus of efforts in stimulating recovery post stroke is the use of exogenously administered cells. The present review focuses on the role of the astrocyte in mediating the brain network, brain plasticity, and neurological recovery post stroke. As a model to describe the interaction of a restorative cell-based therapy with astrocytes, which drives recovery from stroke, we specifically highlight the subacute treatment of stroke with multipotent mesenchymal stromal cell therapy.
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Affiliation(s)
- Yi Li
- Department of Neurology, Henry Ford Hospital, Detroit, Michigan
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19
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Abstract
Obesity is characterized by a chronic and low-grade inflammation in tissues including the hypothalamus. Hypothalamic inflammation is considered an early and determining factor for the onset of obesity, a factor that occurs even before body weight gain. Within the hypothalamus, microglia and astrocytes produce cytokines that drive inflammatory responses. Astrocytes are directly affected by nutrient excess and might play a unique role in promoting hypothalamic inflammatory responses in obesity. This article reviews evidence supporting the role of hypothalamic astrocytes in obesity, and suggests a new approach for neuroendocrine research designed to reveal pathogenesis and develop novel treatment strategies against obesity.
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Affiliation(s)
- Cristina García-Cáceres
- Institute for Diabetes and Obesity, Helmholtz Centre Munich, 85748 Garching, Munich, Germany
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20
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Rozanski GM, Li Q, Stanley EF. Transglial transmission at the dorsal root ganglion sandwich synapse: glial cell to postsynaptic neuron communication. Eur J Neurosci 2013; 37:1221-8. [PMID: 23351144 DOI: 10.1111/ejn.12132] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2012] [Revised: 12/06/2012] [Accepted: 12/15/2012] [Indexed: 11/28/2022]
Abstract
The dorsal root ganglion (DRG) contains a subset of closely-apposed neuronal somata (NS) separated solely by a thin satellite glial cell (SGC) membrane septum to form an NS-glial cell-NS trimer. We recently reported that stimulation of one NS with an impulse train triggers a delayed, noisy and long-lasting response in its NS pair via a transglial signaling pathway that we term a 'sandwich synapse' (SS). Transmission could be unidirectional or bidirectional and facilitated in response to a second stimulus train. We have shown that in chick or rat SS the NS-to-SGC leg of the two-synapse pathway is purinergic via P2Y2 receptors but the second SGC-to-NS synapse mechanism remained unknown. A noisy evoked current in the target neuron, a reversal potential close to 0 mV, and insensitivity to calcium scavengers or G protein block favored an ionotropic postsynaptic receptor. Selective block by D-2-amino-5-phosphonopentanoate (AP5) implicated glutamatergic transmission via N-methyl-d-aspartate receptors. This agent also blocked NS responses evoked by puff of UTP, a P2Y2 agonist, directly onto the SGC cell, confirming its action at the second synapse of the SS transmission pathway. The N-methyl-d-aspartate receptor NR2B subunit was implicated by block of transmission with ifenprodil and by its immunocytochemical localization to the NS membrane, abutting the glial septum P2Y2 receptor. Isolated DRG cell clusters exhibited daisy-chain and branching NS-glial cell-NS contacts, suggestive of a network organization within the ganglion. The identification of the glial-to-neuron transmitter and receptor combination provides further support for transglial transmission and completes the DRG SS molecular transmission pathway.
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Affiliation(s)
- Gabriela M Rozanski
- Laboratory of Synaptic Transmission, Toronto Western Research Institute, Toronto, ON M5T 2S8, Canada
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21
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Liu QS, Xu Q, Kang J, Nedergaard M. Astrocyte activation of presynaptic metabotropic glutamate receptors modulates hippocampal inhibitory synaptic transmission. ACTA ACUST UNITED AC 2012; 1:307-16. [PMID: 16755304 PMCID: PMC1474019 DOI: 10.1017/s1740925x05000190] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
In the CNS, fine processes of astrocytes often wrap around dendrites, axons and synapses, which provides an interface where neurons and astrocytes might interact. We have reported previously that selective Ca(2+) elevation in astrocytes, by photolysis of caged Ca(2+) by o-nitrophenyl-EGTA (NP-EGTA), causes a kainite receptor-dependent increase in the frequency of spontaneous inhibitory post-synaptic potentials (sIPSCs) in neighboring interneurons in hippocampal slices. However, tetrodotoxin (TTX), which blocks action potentials, reduces the frequency of miniature IPSCs (mIPSCs) in interneurons during Ca(2+) uncaging by an unknown presynaptic mechanism. In this study we investigate the mechanism underlying the presynaptic inhibition. We show that Ca(2+) uncaging in astrocytes is accompanied by a decrease in the amplitude of evoked IPSCs (eIPSCs) in neighboring interneurons. The decreases in eIPSC amplitude and mIPSC frequency are prevented by CPPG, a group II/III metabotropic glutamate receptor (mGluR) antagonist, but not by the AMPA/kainate and NMDA receptor antagonists CNQX/CPP. Application of either the group II mGluR agonist DCG IV or the group III mGluR agonist L-AP4 decreased the amplitude of eIPSCs by a presynaptic mechanism, and both effects are blocked by CPPG. Thus, activation of mGluRs mediates the effects of Ca(2+) uncaging on mIPSCs and eIPSCs. Our results indicate that Ca(2+)-dependent release of glutamate from astrocytes can activate distinct classes of glutamate receptors and differentially modulate inhibitory synaptic transmission in hippocampal interneurons.
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Affiliation(s)
- Qing-Song Liu
- Center for Aging and Developmental Biology University of Rochester, NY, USA
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22
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HIV-1 gp120 induces antioxidant response element-mediated expression in primary astrocytes: role in HIV associated neurocognitive disorder. Neurochem Int 2011; 61:807-14. [PMID: 21756955 DOI: 10.1016/j.neuint.2011.06.011] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2011] [Revised: 06/06/2011] [Accepted: 06/18/2011] [Indexed: 11/22/2022]
Abstract
HIV infection affects the central nervous system resulting in HIV associated neurocognitive disorder (HAND), which is characterized by depression, behavioral and motor dysfunctions. The HIV-1 viral envelope protein gp120 is known to induce the release of neurotoxic factors which lead to apoptotic cell death. Although the exact mechanisms involved in HIV-1 gp120-induced neurotoxicity are not completely understood, oxidative stress is suggested to play a vital role in the neuropathogenesis of HAND. Astrocytes represent major population of the non-neuronal cell type in the brain and play a critical role in the neuropathogenesis of HAND. Increased oxidative stress is known to induce nuclear factor erythroid derived 2-related factor 2 (Nrf2), a basic leucine zipper transcription factor which is known to regulate the antioxidant defensive mechanism. However, the role of Nrf2 in HAND has not been elucidated. We report that gp120 significantly upregulates Nrf2 in human astrocytes and is associated with stimulation of key antioxidant defensive enzymes Hemoxygenase (HO-1) and NAD(P)H dehydrogenase quinone1 (Nqo1). Pretreatment of the astrocytes with antioxidants or a specific calcium chelator BAPTA-AM, significantly blocked the upregulation of Nrf2, HO-1 and Nqo1. These results suggest a possible role of the intracellular calcium and oxidative stress in Nrf2 mediated antioxidant defense mechanism, which may have protective role in promoting cell survival.
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23
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Bonansco C, Couve A, Perea G, Ferradas CÁ, Roncagliolo M, Fuenzalida M. Glutamate released spontaneously from astrocytes sets the threshold for synaptic plasticity. Eur J Neurosci 2011; 33:1483-92. [PMID: 21395864 DOI: 10.1111/j.1460-9568.2011.07631.x] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Astrocytes exhibit spontaneous calcium oscillations that could induce the release of glutamate as gliotransmitter in rat hippocampal slices. However, it is unknown whether this spontaneous release of astrocytic glutamate may contribute to determining the basal neurotransmitter release probability in central synapses. Using whole-cell recordings and Ca(2+) imaging, we investigated the effects of the spontaneous astrocytic activity on neurotransmission and synaptic plasticity at CA3-CA1 hippocampal synapses. We show here that the metabolic gliotoxin fluorocitrate (FC) reduces the amplitude of evoked excitatory postsynaptic currents and increases the paired-pulse facilitation, mainly due to the reduction of the neurotransmitter release probability and the synaptic potency. FC also decreased intracellular Ca(2+) signalling and Ca(2+) -dependent glutamate release from astrocytes. The addition of glutamine rescued the effects of FC over the synaptic potency; however, the probability of neurotransmitter release remained diminished. The blockage of group I metabotropic glutamate receptors mimicked the effects of FC on the frequency of miniature synaptic responses. In the presence of FC, the Ca(2+) chelator 1,2-bis(2-aminophenoxy)ethane-N,N,N ',N '-tetra-acetate or group I metabotropic glutamate receptor antagonists, the excitatory postsynaptic current potentiation induced by the spike-timing-dependent plasticity protocol was blocked, and it was rescued by delivering a stronger spike-timing-dependent plasticity protocol. Taken together, these results suggest that spontaneous glutamate release from astrocytes contributes to setting the basal probability of neurotransmitter release via metabotropic glutamate receptor activation, which could be operating as a gain control mechanism that regulates the threshold of long-term potentiation. Therefore, endogenous astrocyte activity provides a novel non-neuronal mechanism that could be critical for transferring information in the central nervous system.
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Affiliation(s)
- Christian Bonansco
- Departamento de Fisiología, Universidad de Valparaíso, Valparaíso, Chile.
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24
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Qu WS, Wang YH, Ma JF, Tian DS, Zhang Q, Pan DJ, Yu ZY, Xie MJ, Wang JP, Wang W. Galectin-1 attenuates astrogliosis-associated injuries and improves recovery of rats following focal cerebral ischemia. J Neurochem 2010; 116:217-26. [PMID: 21054390 DOI: 10.1111/j.1471-4159.2010.07095.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Astrogliosis occurs after brain ischemia, and excessive astrogliosis can devastate the neuronal recovery. Previous reports show that galectin-1 (Gal-1) regulates proliferation of several cell types and plays an important role after nervous system injuries. Here, we found that expression of Gal-1 was remarkably up-regulated in activated astrocytes around ischemic infarct. Furthermore, under ischemic conditions either in vitro or in vivo, Gal-1 was found to inhibit the proliferation of astrocytes in a dose-dependent manner, attenuate astrogliosis and down-regulate the astrogliosis associated expression of nitric oxide synthase and interleukin-1β after the ischemia. All these changes were blocked by lactose, suggesting a lectin dependent manner of Gal-1's function. Moreover, 7-day Gal-1 treatment reduced apoptosis of neurons, decreased brain infarction volume and improved neurological function induced by the ischemia. Together, these findings indicate that through reducing astrogliosis related damages, Gal-1 is a potential therapeutical target for attenuating neuronal damage and promoting recovery of brain ischemia.
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Affiliation(s)
- Wen-Sheng Qu
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
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25
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Cocaine potentiates astrocyte toxicity mediated by human immunodeficiency virus (HIV-1) protein gp120. PLoS One 2010; 5:e13427. [PMID: 20976166 PMCID: PMC2955538 DOI: 10.1371/journal.pone.0013427] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2010] [Accepted: 09/24/2010] [Indexed: 01/18/2023] Open
Abstract
It is becoming widely accepted that psychoactive drugs, often abused by HIV-I infected individuals, can significantly alter the progression of neuropathological changes observed in HIV-associated neurodegenerative diseases (HAND). The underlying mechanisms mediating these effects however, remain poorly understood. In the current study, we explored whether the psychostimulant drug cocaine could exacerbate toxicity mediated by gp120 in rat primary astrocytes. Exposure to both cocaine and gp120 resulted in increased cell toxicity compared to cells treated with either factor alone. The combinatorial toxicity of cocaine and gp120 was accompanied by an increase in caspase-3 activation. In addition, increased apoptosis of astrocytes in the presence of both the agents was associated with a concomitant increase in the production of intracellular reactive oxygen species and loss of mitochondrial membrane potential. Signaling pathways including c-jun N-teminal kinase (JNK), p38, extracellular signal-regulated kinase (ERK)/mitogen-activated protein kinases (MAPK), and nuclear factor (NF-κB) were identified to be major players in cocaine and gp120-mediated apoptosis of astrocytes. Our results demonstrated that cocaine-mediated potentiation of gp120 toxicity involved regulation of oxidative stress, mitochondrial membrane potential and MAPK signaling pathways.
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26
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Zhang S, Liang R, Zhou F, Huang X, Ding JH, Hu G. Reversal of rotenone-induced dysfunction of astrocytic connexin43 by opening mitochondrial ATP-sensitive potassium channels. Cell Mol Neurobiol 2010; 31:111-7. [PMID: 20824494 DOI: 10.1007/s10571-010-9560-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2010] [Accepted: 08/25/2010] [Indexed: 12/21/2022]
Abstract
Growing evidence suggests that the astrocytic gap junctions (GJs), mainly formed by connexin 43 (Cx43), play an important role in physiological maintenance and various central nervous system (CNS) pathological conditions. However, little is known about the role of Cx43 in Parkinson's disease (PD). In this article, we report that rotenone, a classic neurotoxin for PD, could inhibit expression of astrocytic Cx43 and gap junction permeability. ATP-sensitive potassium (K(ATP)) channel openers, iptakalim (IPT) and diazoxide (DZ), exerted protective effect on rotenone-induced dysfunction of Cx43 and astrocyte apoptosis, which was reversed by selective mitochondrial K(ATP) (mitoK(ATP)) channel blocker 5-hydroxydecanoate (5-HD). Taken together, our findings reveal that rotenone-induced dysfunction of astrocytic Cx43 may be involved in the pathology of PD. Moreover, opening mitoK(ATP) channels in astrocytes can reverse rotenone-induced dysfunction of astrocytic Cx43 and therefore protect against toxicity of rotenone on astrocytes.
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Affiliation(s)
- Shu Zhang
- Department of Pharmacology, Nanjing Medical University, Jiangsu, People's Republic of China
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27
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Shen LH, Li Y, Chopp M. Astrocytic endogenous glial cell derived neurotrophic factor production is enhanced by bone marrow stromal cell transplantation in the ischemic boundary zone after stroke in adult rats. Glia 2010; 58:1074-81. [PMID: 20468049 DOI: 10.1002/glia.20988] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Bone marrow stromal cells (BMSCs) facilitate functional recovery in rats after focal ischemic attack. Growing evidence suggests that the secretion of various bioactive factors underlies BMSCs' beneficial effects. This study investigates the expression of glial cell derived neurotrophic factor (GDNF) in the ischemic hemisphere with or without BMSC administration. Adult male Wistar rats were subjected to 2 h of middle cerebral artery occlusion followed by an injection of 3 x 10(6) BMSCs (n = 11) or phosphate-buffered saline (n = 10) into the tail vein 24 h later. Animals were sacrificed seven days later. Single and double immunohistochemical staining was performed to measure GDNF, Ki67, doublecortin, and glial fibrillary acidic protein expression as well as the number of apoptotic cells along the ischemic boundary zone (IBZ) and/or in the subventricular zone (SVZ). BMSC treatment significantly increased GDNF expression and decreased the number of apoptotic cells in the IBZ (P < 0.05). GDNF expression was colocalized with GFAP. Meanwhile, BMSCs increased the number of Ki-67 positive cells and the density of DCX positive migrating neuroblasts (P < 0.05). GDNF expression was significantly increased in single astrocytes collected from animals treated with BMSCs, and in astrocytes cocultured with BMSCs after OGD (P < 0.05). Our data suggest that BMSCs increase GDNF levels in the ischemic hemisphere; the major source of GDNF protein is reactive astrocytes. We propose that the increase of GDNF in response to BMSC administration creates a hospitable environment for local cellular repair as well as for migrating neuroblasts from the SVZ, and thus contributes to the functional improvement.
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Affiliation(s)
- L H Shen
- Department of Neurology, Henry Ford Hospital, 2799 West Grand Boulevard, Detroit, Michigan 48202, USA
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28
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Galectin-1 Enhances Astrocytic BDNF Production and Improves Functional Outcome in Rats Following Ischemia. Neurochem Res 2010; 35:1716-24. [DOI: 10.1007/s11064-010-0234-z] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/16/2010] [Indexed: 10/19/2022]
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29
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Neuron-glial contacts formed in the cerebellum during electrical stimulation in the presence of an NO-generating compound. NEUROSCIENCE AND BEHAVIORAL PHYSIOLOGY 2008; 38:363-8. [PMID: 18401727 DOI: 10.1007/s11055-008-0051-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2006] [Revised: 07/06/2006] [Indexed: 10/22/2022]
Abstract
The molecular layer of the cerebellum of the frog Rana temporaria was studied by light and electron microscopy after electrical stimulation in the presence of an NO-generating compound. In these conditions, there was severe swelling of granule cell axon terminals (boutons) and astrocyte processes (AP), with loss of cytoplasmic elements. However, along with damaged structures, there were also undamaged structures: boutons with synaptic vesicles and AP with glycogen granules. It is suggested that these persisting viable AP may form 1) glial "wrappings" around damaged synapses or boutons and 2) neuron-glial contacts, which form when synaptic vesicles cross damaged bouton membranes to AP containing glycogen granules. It is also suggested that the presence of glycogen in AP in conditions of oxygen and glucose deficiency may provide a source of high-energy substrates such as glucose and ATP, thus providing conditions for neuron survival in pathological states (ischemia/hypoxia).
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Cesa R, Strata P. Activity-dependent axonal and synaptic plasticity in the cerebellum. Psychoneuroendocrinology 2007; 32 Suppl 1:S31-5. [PMID: 17640822 DOI: 10.1016/j.psyneuen.2007.04.016] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2007] [Accepted: 04/06/2007] [Indexed: 12/14/2022]
Abstract
The cerebellum is a brain region endowed with a high degree of plasticity also in adulthood. After damage or alteration in the patterns of activity, it is able to undergo remarkable changes in its architecture and to form new connections based upon a process of synaptic reorganization. This review addresses cellular and molecular mechanisms that regulate the competition between two inputs belonging to different neuronal populations in innervating two contiguous but separate domains of the same target cell. The two inputs are the parallel fibers, the axon of the cerebellar granule cells, and the olivocerebellar neurons, that terminate as climbing fibers in the cerebellar cortex. The target is the Purkinje cell characterized by two dendritic domains that are different in size and number of spines, upon which the two afferent inputs impinge. Both inputs express several genes related to plasticity throughout the life span conferring the ability to remodel their synapses. In addition, we provided evidence that climbing fibers and Purkinje cells show remarkable reciprocal trophic interactions that are required for the maintenance of the correct synaptic connectivity. Through their activity, climbing fibers sustain the competition with parallel fibers by displacing this input to the distal territory of the Purkinje cell dendrite. In addition, they operate on the Purkinje cells through AMPA receptor suppressing spines in the territory surrounding their synapses. In this way, climbing fibers are able to optimize spine distribution and functional connectivity.
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Affiliation(s)
- Roberta Cesa
- Department of Neuroscience, University of Turin, C.so Raffaello 30, 10125 Torino, Italy.
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31
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Zhang S, Zhou F, Ding JH, Zhou XQ, Sun XL, Hu G. ATP-sensitive potassium channel opener iptakalim protects against MPP+-induced astrocytic apoptosis via mitochondria and mitogen-activated protein kinase signal pathways. J Neurochem 2007; 103:569-79. [PMID: 17635669 DOI: 10.1111/j.1471-4159.2007.04775.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Inhibition of astrocytic apoptosis has been regarded as a novel prospective strategy for treating neurodegenerative disorders such as Parkinson's disease. In the present study, we demonstrated that iptakalim (IPT), an ATP-sensitive potassium channel (K(ATP) channel) opener, exerted protective effect on MPP(+)-induced astrocytic apoptosis, which was reversed by selective mitochondrial K(ATP) channel blocker 5-hydroxydecanoate. Further study revealed that IPT inhibited glutathione (GSH) depletion, mitochondrial membrane potential loss and subsequent release of pro-apoptotic factors (cytochrome c and apoptosis-inducing factor (AIF), and c-Jun NH(2)-terminal kinase/mitogen-activated protein kinases (MAPK) phosphorylation induced by MPP(+). Meanwhile, extracellular signal-regulated kinase (ERK) 1/2 inhibitor PD98059 inhibited the protective effect of IPT on MPP(+)-induced astrocytic apoptosis. Furthermore, IPT could also activate ERK/MAPK and maintain increased phospho-ERK1/2 level after MPP(+) exposure. Taken together, these findings reveal for the first time that IPT protects against MPP(+)-induced astrocytic apoptosis via inhibition of mitochondria apoptotic pathway and regulating the MAPK signal transduction pathways by opening mitochondrial ATP-sensitive potassium (mitoK(ATP)) channels in astrocytes. And targeting K(ATP) channels expressed in astrocytes may provide a novel therapeutic strategy for neurodegenerative disorders.
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Affiliation(s)
- Shu Zhang
- Laboratory of Neuropharmacology, Institute of Neurosciences, Nanjing Medical University, Nanjing, Jiangsu, P. R. China
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32
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Cesa R, Scelfo B, Strata P. Activity-dependent presynaptic and postsynaptic structural plasticity in the mature cerebellum. J Neurosci 2007; 27:4603-11. [PMID: 17460073 PMCID: PMC6673001 DOI: 10.1523/jneurosci.5617-06.2007] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Two models of spine formation have been proposed. Spines can derive from emerging dendritic filopodia that have encountered presynaptic partners, or presynaptic molecules may induce the spine maturation event directly from the dendritic shaft. The first model applies better to the Purkinje cell (PC), because numerous free spines have been described in several conditions, particularly when granule cells degenerate before parallel fiber (PF) synapses are formed. A large number of new spines, many of them being free, appear in the proximal dendritic domain after blockage of electrical activity by tetrodotoxin (TTX). A complete blockage of the AMPA receptors by NBQX (2,3-dioxo-6-nitro-1,2,3,4-tetrahydrobenzoquinoxaline-7-sulfonamide), leading to a complete absence of PF- and climbing fiber (CF)-evoked EPSCs and of spontaneous glutamatergic quantal events, mimics the TTX effect. In contrast, metabotropic glutamate receptor blockage by MCPG [(S)-alpha-methyl-4-carboxyphenylglycine] is ineffective. In normal conditions, in the proximal dendritic domain of the PC, clusters of a few spines are present only under each CF varicosity. It has been proposed that the active CF is responsible for spine pruning in the territory surrounding the CF synapses. Here, we show that such a pruning is mediated by AMPA but not by metabotropic receptors. Finally, after AMPA receptor blockage, there is a reduced number of spines in each spine cluster underlying CF varicosity. In conclusion, PCs tend to express spines over the entire dendritic territory. CF activity reinforces the CF synaptic contacts and actively suppresses spines in the surrounding territory, which is an effect mediated by AMPA receptors.
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Affiliation(s)
- Roberta Cesa
- Department of Neuroscience, University of Turin, 10125 Torino, Italy.
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Neusch C, Bähr M, Schneider-Gold C. Glia cells in amyotrophic lateral sclerosis: New clues to understanding an old disease? Muscle Nerve 2007; 35:712-24. [PMID: 17373702 DOI: 10.1002/mus.20768] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
In classic neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS), the pathogenic concept of a cell-autonomous disease of motor neurons has been challenged increasingly in recent years. Macro- and microglial cells have come to the forefront for their role in multistep degenerative processes in ALS and respective disease models. The activation of astroglial and microglial cells occurs early in the pathogenesis of the disease and seems to greatly influence disease onset and promotion. The role of oligodendrocytes and Schwann cells remains elusive. In this review we highlight the impact of nonneuronal cells in ALS pathology. We discuss diverse glial membrane proteins that are necessary to control neuronal activity and neuronal cell survival, and summarize the contribution of these proteins to motor neuron death in ALS. We also describe recently discovered glial mechanisms that promote motor neuron degeneration using state-of-the-art genetic mouse technology. Finally, we provide an outlook on the extent to which these new pathomechanistic insights may offer novel therapeutic approaches.
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Affiliation(s)
- Clemens Neusch
- Department of Neurology, University of Göttingen, Robert-Koch-Str. 40, 37075 Göttingen, Germany.
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34
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Schizophrenia-associated neural growth factors in peripheral blood. A review. Eur Neuropsychopharmacol 2006; 16:469-80. [PMID: 16545550 DOI: 10.1016/j.euroneuro.2006.02.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2005] [Revised: 01/25/2006] [Accepted: 02/02/2006] [Indexed: 01/03/2023]
Abstract
In this paper we review the findings on neural growth factors in the peripheral blood of schizophrenia patients. The studies we review provide evidence for the fact that in schizophrenia the levels of growth factors in peripheral blood are disturbed. The most robust results (7 studies) are reported for S100B protein, which seems to be elevated in acute psychosis and in patients with predominant negative symptoms. We conclude that there are aberrant levels of growth factors in peripheral blood in schizophrenia patients, probably most notably in patients with negative symptoms. Large-scale longitudinal multivariate studies, investigating the levels of several growth factors at the same time might give insight in etiological processes and identify clinically useful subsets of patients within the heterogeneous schizophrenia sample.
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Reigada D, Lu W, Mitchell CH. Glutamate acts at NMDA receptors on fresh bovine and on cultured human retinal pigment epithelial cells to trigger release of ATP. J Physiol 2006; 575:707-20. [PMID: 16809361 PMCID: PMC1995677 DOI: 10.1113/jphysiol.2006.114439] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
The photoreceptors lie between the inner retina and the retinal pigment epithelium (RPE). The release of glutamate by the phototoreceptors can signal changes in light levels to inner retinal neurons, but the role of glutamate in communicating with the RPE is unknown. Since RPE cells are known to release ATP, we asked whether glutamate could trigger ATP release from RPE cells and whether this altered cell signalling. Stimulation of the apical face of fresh bovine RPE eyecups with 100 mum NMDA increased ATP levels more than threefold, indicating that both receptors for NMDA and release of ATP occurred across the apical membrane of fresh RPE cells. NMDA increased ATP levels bathing cultured human ARPE-19 cells more than twofold, with NMDA receptor inhibitors MK-801 and d-AP5 preventing this release. Blocking the glycine site of the NMDA receptor with 5,7-dichlorokynurenic acid prevented ATP release from ARPE-19 cells. Release was also blocked by channel blocker NPPB and Ca(2+) chelator BAPTA, but not by cystic fibrosis transmembrane conductance regulator (CFTR) blocker glibenclamide or vesicular release inhibitor brefeldin A. Glutamate produced a dose-dependent release of ATP from ARPE-19 cells that was substantially inhibited by MK-801. NMDA triggered a rise in cell Ca(2+) that was blocked by MK-801, by the ATPase apyrase, by the P2Y(1) receptor antagonist MRS2179 and by depletion of intracellular Ca(2+) stores with thapsigargin. These results suggest that glutamate stimulates NMDA receptors on the apical membrane of RPE cells to release ATP. This secondary release can amplify the glutaminergic signal by increasing Ca(2+) inside RPE cells, and might activate Ca(2+)-dependent conductances. The interplay between glutaminergic and purinergic systems may thus be important for light-dependent interactions between photoreceptors and the RPE.
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Affiliation(s)
- David Reigada
- Department of Physiology, University of Pennsylvania, 3700 Hamilton Walk, Philadelphia, PA 19104-6085, USA
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36
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Gensert JM, Ratan RR. The metabolic coupling of arginine metabolism to nitric oxide generation by astrocytes. Antioxid Redox Signal 2006; 8:919-28. [PMID: 16771682 DOI: 10.1089/ars.2006.8.919] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Arginine, the only known precursor of nitric oxide, enters the brain parenchyma from the blood through the endothelial cells or from the cerebral spinal fluid through the ependymal cells. Astrocytes, whose processes abut the endothelium and ependymum, take up arginine through cationic amino acid transporters and release arginine through this transport system to the synapses that astrocytes shield. Some of these synapses are excitatory, and liberate glutamate into the synaptic cleft. Glutamate induces arginine release from astrocytes, making it available to the neuron. Neurons can take up arginine to be used in nitric oxide-mediated processes, such as neurotransmission. Thus, neural and nonneural cells act in concert to affect neuron physiology in an elegantly integrated system. This review focuses on the components of the interaction between astrocytes and neurons in nitric oxide biology.
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Affiliation(s)
- Joann M Gensert
- Burke/Cornell Medical Research Institute, White Plains, New York 10605, USA.
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37
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Abstract
Reactive astrocytosis occurs prominently in response to all forms of CNS injury or disease. The functions of reactive astrocytes are not well understood, and both harmful and beneficial activities have been attributed to these cells. The basic process of reactive astrocytosis is conserved in vertebrate evolution, suggesting fitness-enhancing benefits, but scar-forming reactive astrocytes are often regarded as uniformly detrimental to clinical outcome, in particular, when implicated as inhibitors of axon regeneration. Transgenic mouse models are providing new means to study the activities of reactive astrocytes after CNS insults in vivo. Recent studies point toward roles for reactive astrocytes in restricting inflammation and protecting neurons and oligodendrocytes, thereby helping to limit tissue degeneration and preserve function after CNS injury.
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Affiliation(s)
- Michael V Sofroniew
- Department of Neurobiology and Brain Research Institute, University of California, Los Angeles, CA 90095-1763, USA.
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Chen MJ, Ivy AS, Russo-Neustadt AA. Nitric oxide synthesis is required for exercise-induced increases in hippocampal BDNF and phosphatidylinositol 3' kinase expression. Brain Res Bull 2005; 68:257-68. [PMID: 16377431 DOI: 10.1016/j.brainresbull.2005.08.013] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2005] [Revised: 08/16/2005] [Accepted: 08/23/2005] [Indexed: 02/04/2023]
Abstract
Previous studies have shown that running exercise, either alone or in combination with antidepressant treatment, results in increased hippocampal BDNF levels. Nitric oxide (NO) is an important signaling molecule that has neuronal survival-promoting properties and has been shown to play an important role in plasticity associated with activating interventions. Herein, we administered the NO synthase (NOS) inhibitor, N-nitro-L-arginine methyl ester (L-NAME), in conjunction with the monoamine oxidase inhibitor (MAOI) antidepressant, tranylcypromine, and voluntary wheel-running exercise to determine whether the enhancement in full-length BDNF mRNA occurring with these interventions is dependent upon NO synthesis. Our results demonstrate that both chronic exercise and chronic exercise-plus-tranylcypromine lead to enhanced hippocampal BDNF mRNA and protein expression. NOS inhibition prevents this effect of chronic exercise, but only partly prevents the effects of the exercise/antidepressant combination. Thus, the robust enhancement in BDNF mRNA occurring with exercise appears to be NO synthesis-dependent, but the intervention including antidepressant may enhance BDNF expression through alternative intracellular mechanisms. In addition, because exercise and antidepressants have both been shown to activate survival-promoting genes, we evaluated the levels of hippocampal phosphatidylinositol 3' kinase (PI-3K), an important signaling molecule within a principal neuronal survival-promoting intracellular pathway. Like BDNF mRNA and protein, exercise increases the expression of PI-3K, whereas concomitant NOS inhibition prevents this increase in PI-3K immunoreactivity above control levels. Our results are discussed in light of possible overlapping, but distinct intracellular pathways activated by exercise and antidepressant treatment to bring about enhancements in BDNF expression and other survival-promoting effects. These findings further demonstrate the potential therapeutic potential of chronic exercise to supplement pharmacotherapeutic treatment of mood disorders.
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Affiliation(s)
- Michael J Chen
- Department of Biological Sciences, California State University, 5151 State University Drive, Los Angeles, 90032, USA.
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Yoshida Y, Tsuchiya R, Matsumoto N, Morita M, Miyakawa H, Kudo Y. Ca2+-Dependent Induction of Intracellular Ca2+ Oscillation in Hippocampal Astrocytes During Metabotropic Glutamate Receptor Activation. J Pharmacol Sci 2005; 97:212-8. [PMID: 15684567 DOI: 10.1254/jphs.fp0040722] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
We have investigated whether the intracellular calcium concentration ([Ca(2+)](i)) oscillations induced in astrocytes using the metabotropic glutamate-receptor agonist, (1S,3R)-1-aminocyclopentane-1,3-dicarboxylic acid (t-ACPD) are Ca(2+)-dependent, using three different Ca(2+) indicators with different affinities for Ca(2+). When rat hippocampal cells in culture were loaded with fura-2 (K(d): 145 nM), two-thirds of the cells showed obvious oscillatory increase in [Ca (2+)](i) during t-ACPD-administration. Those cells were identified as astrocytes by immuno-histochemistry in our previous paper. In cells loaded with fura-2FF (K(d): 25,000 nM), a similar percentage of t-ACPD-responsive cells showed oscillatory [Ca(2+)](i) changes. However, in cells loaded with quin-2 (K(d): 60 nM), t-ACPD induced no oscillatory responses, but some cells showed a small transient increase in the [Ca(2+)](i). The same small transient [Ca(2+)](i) increase was seen in cells loaded with both fura-2FF and BAPTA, a Ca(2+) chelator (K(d): 135 nM). These findings indicate the involvement of [Ca(2+)](i)-dependent regulatory mechanisms in the induction of the t-ACPD-induced oscillatory change in the [Ca(2+)](i) in astrocytes.
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Affiliation(s)
- Yoshitoku Yoshida
- Molecular Life Science Division, School of Life Science, Tokyo University of Pharmacy and Life Science, Japan
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40
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Geurts JJG, Wolswijk G, Bö L, Redeker S, Ramkema M, Troost D, Aronica E. Expression patterns of Group III metabotropic glutamate receptors mGluR4 and mGluR8 in multiple sclerosis lesions. J Neuroimmunol 2005; 158:182-90. [PMID: 15589052 DOI: 10.1016/j.jneuroim.2004.08.012] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2004] [Revised: 07/30/2004] [Accepted: 08/02/2004] [Indexed: 11/16/2022]
Abstract
Recent evidence supports a role for metabotropic glutamate receptors (mGluRs) in neuroinflammatory diseases. In the present study, we have investigated whether the group III mGluR subtypes mGluR4 and mGluR8 are expressed in MS lesions at various stages of evolution. In control patient tissue and in normal-appearing MS white matter (NAWM), no microglial or astrocyte staining was detected. In contrast, in active lesions, mGluR8 immunoreactivity (IR) was detected in cells of the microglia/macrophage lineage. Fewer macrophage-like cells were positive for mGluR8 in chronic active and inactive lesions. No mGluR4 IR was detected in cells of the microglia/macrophage lineage in the MS lesions studied. In chronic active lesions, however, a population of reactive astrocytes localized in the rim of the lesions expressed both mGluR4 and mGluR8. Our results suggest a role for these receptor subtypes in the inflammatory response in MS that involves both astrocytes and cells of the microglia/macrophage lineage.
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Affiliation(s)
- J J G Geurts
- MS Research Center, VU Medical Center, Amsterdam, The Netherlands
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Segieth J, Fowler L, Whitton PS, Pearce B. Arginine release from rat cerebellar astrocytes: autocrine roles for glutamate and nitric oxide? Neurosci Lett 2004; 372:262-5. [PMID: 15542252 DOI: 10.1016/j.neulet.2004.09.049] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2004] [Revised: 09/09/2004] [Accepted: 09/22/2004] [Indexed: 11/26/2022]
Abstract
In this study we have investigated the relationship between glutamate and arginine release from cultured cerebellar astrocytes. We found that the nitric oxide (NO) donor S-nitroso-N-acetylpenicillamine (SNAP) promoted the release of both amino acids in a concentration-dependent manner, and that these responses were partially reversed by a guanylate cyclase inhibitor. Application of the non-NMDA glutamate receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) resulted in a 60% reduction in basal arginine release but no change in that of glutamate. This effect was not overcome by the subsequent addition of SNAP despite a two-fold increase in glutamate release. Incubation with the nitric oxide synthase (NOS) inhibitor N-nitro-L-arginine methyl ester (L-NAME) elicited 40 and 60% reductions in the basal release of glutamate and arginine, respectively. Basal release of both amino acids was restored by the addition of SNAP. We conclude that glutamate released from cerebellar astrocytes in response to increased levels of extracellular NO acts in an autocrine manner to promote arginine release via the activation of non-NMDA receptors. In addition, our data suggest that basal glutamate release is regulated to some extent by tonic NO synthesis in these cells.
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Affiliation(s)
- Joanna Segieth
- Department of Pharmacology, The School of Pharmacy, 29/39 Brunswick Square, London WC1N 1AX, UK
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Abstract
Abstract Although glia often envelop synapses, they have traditionally been viewed as passive participants in synaptic function. Recent evidence has demonstrated, however, that there is a dynamic two-way communication between glia and neurons at the synapse. Neurotransmitters released from presynaptic neurons evoke Ca2+ concentration increases in adjacent glia. Activated glia, in turn, release transmitters, including glutamate and ATP. These gliotransmitters feed back onto the presynaptic terminal either to enhance or to depress further release of neurotransmitter. Transmitters released from glia can also directly stimulate postsynaptic neurons, producing either excitatory or inhibitory responses. Based on these new findings, glia should be considered an active partner at the synapse, dynamically regulating synaptic transmission.
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Affiliation(s)
- Eric A Newman
- Department of Neuroscience, University of Minnesota, 6-145 Jackson Hall, 321 Church Street SE, Minneapolis, MN 55455, USA.
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Rao TS, Lariosa-Willingham KD, Yu N. Glutamate-dependent glutamine, aspartate and serine release from rat cortical glial cell cultures. Brain Res 2003; 978:213-22. [PMID: 12834916 DOI: 10.1016/s0006-8993(03)02841-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Glia play a pivotal role in glutaminergic excitatory neurotransmission in the central nervous system by regulating synaptic levels of glutamate and by providing glutamine as the sole precursor for the neurotransmitter pool glutamate to neurons through the glutamate-glutamine cycle. In the present investigation, we examined the influence of glutamate application on glutamine, serine and aspartate release from rat cortical glial cultures. The glial glutamate transporters rapidly cleared exogenously applied glutamate and this was accompanied by rapid increases in aspartate and glutamine, and a delayed increase in serine levels in the glial-conditioned medium. While glutamate-induced increases in glutamine and serine were sustained for up to 24 h, increases in aspartate lasted only for up to 6 h. The glutamate-induced increases in aspartate and glutamine were dependent both on the concentration and the duration of glutamate stimulus, but were largely insensitive to the inhibition of non-N-methyl-D-aspartate receptors or the metabotropic glutamate receptor 5. Inhibition of the glutamate transporter function by L-trans-pyrrolidine 2,4-dicarboxylate decreased the rate of glutamate uptake but not completely abrogated the uptake process, and this resulted in the attenuation of rate of glutamate induced glutamine synthesis. Dexamethasone treatment increased serine and glutamine levels in conditioned medium and increased glutamate induced glutamine release suggesting an upregulation of glutamine synthase activity. These results further substantiate coupling between glutamate and glutamine, and shed light on glutamate-dependent release of serine and aspartate, which may further contribute to excitatory neurotransmission.
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Affiliation(s)
- Tadimeti S Rao
- Merck Research Laboratories, 3535 General Atomics Ct, MRLSDB1, San Diego, CA 92122, USA.
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44
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Bal-Price A, Moneer Z, Brown GC. Nitric oxide induces rapid, calcium-dependent release of vesicular glutamate and ATP from cultured rat astrocytes. Glia 2002; 40:312-23. [PMID: 12420311 DOI: 10.1002/glia.10124] [Citation(s) in RCA: 172] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Nitric oxide (NO; 1 microM) or an NO donor (500 microM diethylenetriamine-nitric oxide, DETA-NONOate) caused rapid glutamate and ATP release from cultured rat cortical astrocytes. NO-induced glutamate release was prevented by calcium chelators (EGTA or BAPTA-AM) and an inhibitor of vesicular exocytosis (botulinum neurotoxin C, BoTx-C), but not by a glutamate transport inhibitor, L-trans-pyrrolidine-2,4-dicarboxylate (t-PDC), a cyclooxygenase inhibitor (indomethacin), or an inhibitor of soluble guanylate cyclase 1H-[1,2,4]oxadiazolo-[4,3-a]quinoxalin-1-one (ODQ), and was not induced by mitochondrial respiratory inhibitors (myxothiazol or azide). Similarly to glutamate, NO-induced ATP release was also completely blocked by BAPTA-AM and BoTx-C, suggesting again a vesicular, calcium-dependent mechanism of release. Addition of DETA-NONOate (500 microM) to fura-2-loaded astrocytes induced a rapid, transient increase in intracellular calcium levels followed by a lower, sustained level of calcium entry. The latter was blocked by gadolinium (1 microM), an inhibitor of capacitative Ca(2+) entry. Thus, NO appears to cause rapid exocytosis of vesicular glutamate and ATP from astrocytes by raising intracellular calcium levels. Astrocytes activated by lipopolysaccharide/endotoxin and interferon-gamma to express inducible NO synthase (iNOS) maintained substantially higher extracellular glutamate levels than nonactivated cells or activated cells treated with an iNOS inhibitor (1400W), but the rate of glutamate uptake by these cells was similar. This suggests that NO from inflammatory-activated astrocytes causes release of astrocytic glutamate. NO-induced release of astrocytic glutamate and ATP may be important in physiological or pathological communication between astrocytes and neurons.
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Affiliation(s)
- Anna Bal-Price
- Department of Biochemistry, University of Cambridge, Cambridge, UK.
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