201
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Krieger NS, Frick KK, LaPlante Strutz K, Michalenka A, Bushinsky DA. Regulation of COX-2 mediates acid-induced bone calcium efflux in vitro. J Bone Miner Res 2007; 22:907-17. [PMID: 17352658 DOI: 10.1359/jbmr.070316] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
UNLABELLED Chronic metabolic acidosis induces net Ca efflux from bone; this osteoclastic bone resorption is mediated by increased osteoblastic prostaglandin synthesis. Cyclooxygenase, the rate-limiting enzyme in prostaglandin synthesis, is present in both constitutive (COX-1) and inducible (COX-2) forms. We report here that acidosis increases both osteoblastic RNA and protein levels for COX-2 and that genetic deficiency or pharmacologic inhibition of COX-2 significantly reduces acid-induced Ca efflux from bone. INTRODUCTION Incubation of neonatal mouse calvariae in medium simulating physiologic metabolic acidosis induces an increase in osteoblastic prostaglandin E2 (PGE2) release and net calcium (Ca) efflux from bone. Increased PGE2 is necessary for acid-induced bone resorption, because inhibition of cyclooxygenase activity with indomethacin significantly decreases not only PGE2 production but also Ca release. Cyclooxygenase is present in both constitutive (COX-1) and inducible (COX-2) forms. Because COX-2 activity has been implicated in several forms of pathological bone resorption, we tested the hypothesis that COX-2 is critical for acid-induced, cell-mediated bone Ca efflux. MATERIALS AND METHODS To determine the effect of metabolic acidosis on COX-2 RNA and protein, primary cells isolated from neonatal CD-1 mouse calvariae were cultured in neutral (Ntl) or physiologically acidic medium (Met). RNA levels for COX-2 and COX-1 were measured by quantitative real-time PCR. Levels of COX-2 and COX-1 protein were measured by immunoblot analysis. To determine the effect of acidosis on bone Ca efflux in genetically deficient COX-2 mice, mice heterozygous for the COX-2 knockout (strain B6;129S7-Ptgs2(tm1Jed)/J) were used as breeders, and neonatal calvariae were cultured in Ntl or Met. To determine the effects of the specific COX-2 inhibitor, NS398, on acid-induced bone resorption, CD-1 calvariae were incubated in Ntl or Met with or without NS398 (1 microM). Medium PGE2 was assayed by ELISA. RESULTS Incubation of mouse calvarial cells in Met significantly increased COX-2 RNA and protein levels without a change in COX-1. Increased COX-2 protein levels in response to Met were also observed in cultured calvariae. Acid-induced, cell-mediated Ca efflux from B6;129S7-Ptgs2(tm1Jed)/J calvariae was dependent on genotype. From 0 to 24 h, when physicochemical Ca efflux predominates, Met significantly increased net Ca efflux in all genotypes. After 24 h, when cell-mediated Ca efflux predominates, Met induced greater Ca efflux from (+/+) than from (+/-), and there was no increase from (-/-). In calvariae from CD-1 mice, NS398 significantly inhibited both the acid-induced increase in PGE2 and Ca release. CONCLUSIONS The specific acid-induced increase in COX-2 RNA and protein levels and the dependency of the increased Ca efflux on COX-2 activity, as determined by both genetic deficiency and pharmacologic inhibition, show that COX-2 is critical for acid-induced, cell-mediated bone resorption.
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Affiliation(s)
- Nancy S Krieger
- Department of Medicine, Division of Nephrology, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642, USA
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202
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Zhang X, Neufeld AH. Signal transduction pathways for epidermal growth factor stimulated cyclooxygenase-2 induction in astrocytes. Exp Eye Res 2007; 85:280-8. [PMID: 17604021 DOI: 10.1016/j.exer.2007.05.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2007] [Revised: 05/03/2007] [Accepted: 05/04/2007] [Indexed: 11/21/2022]
Abstract
Cyclooxygenase-2 (COX-2) derived prostaglandins (PGs) are pathophysiological mediators in various disease states. Recently, we have demonstrated the rapid, epidermal growth factor receptor (EGFR)-dependent induction of COX-2 and PGE(2) synthesis in astrocytes following optic nerve injury and in culture. We have now investigated the signal transduction pathways activated by EGFR to accomplish the expression of COX-2 in primary optic nerve astrocytes. When astrocytes were exposed to EGF, marked, rapid gene expression of COX-2 was observed. Activation of EGFR caused an increase in the phosphorylation of extracellular signal-regulated kinase (ERK), p38 MAPK (p38) and c-Jun NH (2)-terminal kinase (JNK). Furthermore, U0126, an ERK pathway inhibitor, and SB203580, a p38 MAPK inhibitor, diminished EGF-induced COX-2 expression; whereas, a JNK inhibitor did not suppress COX-2 expression by EGF. Using inhibitors of several other signaling cascades, we found that, unlike epithelial and cancer cells, NF-kappaB, PI 3-kinase/Akt and PKC were not signaling pathways for EGFR-dependent induction of COX-2 in optic nerve astrocytes. Taken together, these data suggest that ERK and p38 are key components of the intracellular signaling switch that transduces EGFR activation into COX-2 induction and PGE(2) biosynthesis in optic nerve astrocytes.
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Affiliation(s)
- Xu Zhang
- Laboratory for the Investigation of the Aging Retina, Department of Ophthalmology, Northwestern University School of Medicine, Tarry 13-753, 303 East Chicago Avenue, Chicago, IL 60611, USA
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203
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Lee CR, North KE, Bray MS, Couper DJ, Heiss G, Zeldin DC. Cyclooxygenase polymorphisms and risk of cardiovascular events: the Atherosclerosis Risk in Communities (ARIC) study. Clin Pharmacol Ther 2007; 83:52-60. [PMID: 17495879 PMCID: PMC2244790 DOI: 10.1038/sj.clpt.6100221] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Cyclooxygenase-derived prostaglandins modulate cardiovascular disease risk. We genotyped 2212 Atherosclerosis Risk in Communities study participants (1,023 incident coronary heart disease (CHD) cases; 270 incident ischemic stroke cases; 919 non-cases) with available DNA for polymorphisms in PTGS1 and PTGS2. Using a case-cohort design, associations between genotype and CHD or stroke risk were evaluated using proportional hazards regression. In Caucasians, the reduced function PTGS1 -1006A variant allele was significantly more common among stroke cases compared to non-cases (18.2 versus 10.6%, P=0.027). In African Americans, the reduced function PTGS2 -765C variant allele was significantly more common in stroke cases (61.4 versus 49.4%, P=0.032). No significant relationships with CHD risk were observed. However, aspirin utilization appeared to modify the relationship between the PTGS2 G-765C polymorphism and CHD risk (interaction P=0.072). These findings suggest that genetic variation in PTGS1 and PTGS2 may be important risk factors for the development of cardiovascular disease events. Confirmation in independent populations is necessary.
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Affiliation(s)
- CR Lee
- Division of Intramural Research, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina, USA
- Division of Pharmacotherapy and Experimental Therapeutics, School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - KE North
- Department of Epidemiology, School of Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - MS Bray
- Department of Pediatrics, Children’s Nutrition Research Center, Baylor College of Medicine, Houston, Texas, USA
| | - DJ Couper
- Department of Biostatistics, School of Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - G Heiss
- Department of Epidemiology, School of Public Health, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - DC Zeldin
- Division of Intramural Research, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina, USA
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204
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Toscano CD, Prabhu VV, Langenbach R, Becker KG, Bosetti F. Differential gene expression patterns in cyclooxygenase-1 and cyclooxygenase-2 deficient mouse brain. Genome Biol 2007; 8:R14. [PMID: 17266762 PMCID: PMC1839133 DOI: 10.1186/gb-2007-8-1-r14] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2006] [Revised: 11/09/2006] [Accepted: 01/31/2007] [Indexed: 12/30/2022] Open
Abstract
Microarray analysis of gene expression in the cerebral cortex and hippocampus of mice deficient in cyclooxygenase-1 or cyclooxygenase-2 reveals that the two enzymes differentially modulate brain gene expression. Background Cyclooxygenase (COX)-1 and COX-2 produce prostanoids from arachidonic acid and are thought to have important yet distinct roles in normal brain function. Deletion of COX-1 or COX-2 results in profound differences both in brain levels of prostaglandin E2 and in activation of the transcription factor nuclear factor-κB, suggesting that COX-1 and COX-2 play distinct roles in brain arachidonic acid metabolism and regulation of gene expression. To further elucidate the role of COX isoforms in the regulation of the brain transcriptome, microarray analysis of gene expression in the cerebral cortex and hippocampus of mice deficient in COX-1 (COX-1-/-) or COX-2 (COX-2-/-) was performed. Results A majority (>93%) of the differentially expressed genes in both the cortex and hippocampus were altered in one COX isoform knockout mouse but not the other. The major gene function affected in all genotype comparisons was 'transcriptional regulation'. Distinct biologic and metabolic pathways that were altered in COX-/- mice included β oxidation, methionine metabolism, janus kinase signaling, and GABAergic neurotransmission. Conclusion Our findings suggest that COX-1 and COX-2 differentially modulate brain gene expression. Because certain anti-inflammatory and analgesic treatments are based on inhibition of COX activity, the specific alterations observed in this study further our understanding of the relationship of COX-1 and COX-2 with signaling pathways in brain and of the therapeutic and toxicologic consequences of COX inhibition.
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Affiliation(s)
- Christopher D Toscano
- Brain Physiology and Metabolism Section, National Institute on Aging, National Institutes of Health, Bldg. 9, Rm. 1S126, 9 Memorial Drive, Bethesda, Maryland 20892, USA
| | - Vinaykumar V Prabhu
- Gene Expression and Genomics Unit, National Institute on Aging, National Institutes of Health, Gerontology Research Center, 5600 Nathan Shock Drive, Baltimore, Maryland, 21224, USA
| | - Robert Langenbach
- Laboratory of Molecular Carcinogenesis, National Institute of Environmental Health Sciences, National Institutes of Health, 111 TW Alexander Drive, Research Triangle Park, North Carolina, 27709, USA
| | - Kevin G Becker
- Gene Expression and Genomics Unit, National Institute on Aging, National Institutes of Health, Gerontology Research Center, 5600 Nathan Shock Drive, Baltimore, Maryland, 21224, USA
| | - Francesca Bosetti
- Brain Physiology and Metabolism Section, National Institute on Aging, National Institutes of Health, Bldg. 9, Rm. 1S126, 9 Memorial Drive, Bethesda, Maryland 20892, USA
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205
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Bosetti F. Arachidonic acid metabolism in brain physiology and pathology: lessons from genetically altered mouse models. J Neurochem 2007; 102:577-86. [PMID: 17403135 PMCID: PMC2084377 DOI: 10.1111/j.1471-4159.2007.04558.x] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The arachidonic acid (AA) cascade involves the release of AA from the membrane phospholipids by a phospholipase A(2), followed by its subsequent metabolism to bioactive prostanoids by cyclooxygenases coupled with terminal synthases. Altered brain AA metabolism has been implicated in neurological, neurodegenerative, and psychiatric disorders. The development of genetically altered mice lacking specific enzymes of the AA cascade has helped to elucidate the individual roles of these enzymes in brain physiology and pathology. The roles of AA and its metabolites in brain physiology, with a particular emphasis on the phospholipase A(2)/cyclooxygenases pathway, are summarized, and the specific phenotypes of genetically altered mice relevant to brain physiology and neurotoxic models are discussed.
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Affiliation(s)
- Francesca Bosetti
- Brain Physiology and Metabolism Section, National Institute on Aging, National Institutes of Health, Bethesda, Maryland, USA.
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206
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Basselin M, Villacreses NE, Lee HJ, Bell JM, Rapoport SI. Chronic lithium administration attenuates up-regulated brain arachidonic acid metabolism in a rat model of neuroinflammation. J Neurochem 2007; 102:761-72. [PMID: 17488274 DOI: 10.1111/j.1471-4159.2007.04593.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Neuroinflammation, caused by a 6-day intracerebroventricular infusion of lipopolysaccharide (LPS) in rats, is associated with the up-regulation of brain arachidonic acid (AA) metabolism markers. Because chronic LiCl down-regulates markers of brain AA metabolism, we hypothesized that it would attenuate increments of these markers in LPS-infused rats. Incorporation coefficients k* of AA from plasma into brain, and other brain AA metabolic markers, were measured in rats that had been fed a LiCl or control diet for 6 weeks, and subjected in the last 6 days on the diet to intracerebroventricular infusion of artificial CSF or of LPS. In rats on the control diet, LPS compared with CSF infusion increased k* significantly in 28 regions, whereas the LiCl diet prevented k* increments in 18 of these regions. LiCl in CSF infused rats increased k* in 14 regions, largely belonging to auditory and visual systems. Brain cytoplasmic phospholipase A(2) activity, and prostaglandin E(2) and thromboxane B(2) concentrations, were increased significantly by LPS infusion in rats fed the control but not the LiCl diet. Chronic LiCl administration attenuates LPS-induced up-regulation of a number of brain AA metabolism markers. To the extent that this up-regulation has neuropathological consequences, lithium might be considered for treating human brain diseases accompanied by neuroinflammation.
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Affiliation(s)
- Mireille Basselin
- Brain Physiology and Metabolism Section, National Institute on Aging, National Institutes of Health, Bethesda 20892-0947, Maryland, USA.
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207
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Ahmad AS, Zhuang H, Echeverria V, Doré S. Stimulation of prostaglandin EP2 receptors prevents NMDA-induced excitotoxicity. J Neurotrauma 2007; 23:1895-903. [PMID: 17184197 DOI: 10.1089/neu.2006.23.1895] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Prostaglandin E(2) (PGE(2)) plays an important role in inflammation and neurologic disorders. The neuromodulatory effects of PGE(2) are mediated through regulation of four G-protein-coupled receptors known as EP1, EP2, EP3, and EP4. The goal of the current study was to determine whether EP2 receptor activation protects neurons from acute NMDA-mediated excitotoxicity. To examine the effects of EP2 activation, mice were given an injection of the EP2 receptor-selective agonist butaprost (K (i) = 110 nM for EP2 receptor; K (i) > 10,000 for other prostaglandin receptors) in the cerebral ventricle and then an injection of NMDA in the right striatum. After 48 h, a significant reduction in NMDA-induced lesion volume was observed in groups pretreated with butaprost (1-300 nmol/L), with maximal protection at 100 nmol/L (p < 0.001). To determine if EP2-activated protection was specific to neurons, mouse neuronal cultures were treated with butaprost, and cell viability was analyzed after 24 h of NMDA excitotoxicity. The results showed that butaprost significantly increased neuron survival in a dose-dependent fashion. Furthermore, treatment of primary neurons with butaprost significantly increased cAMP levels (p < 0.001). Together, these data reveal that EP2 receptor stimulation mediates neuroprotection against NMDA excitotoxicity both in vivo and in vitro and that butaprost can limit acute brain damage. Development and testing of specific PGE(2) receptor mimetics could lead to a decrease in side effects associated with anti-inflammatory drugs and could help to fight acute and/or chronic neurologic disorders.
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Affiliation(s)
- Abdullah Shafique Ahmad
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
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208
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Brady KM, Texel SJ, Kishimoto K, Koehler RC, Sapirstein A. Cytosolic phospholipase A alpha modulates NMDA neurotoxicity in mouse hippocampal cultures. Eur J Neurosci 2007; 24:3381-6. [PMID: 17229087 DOI: 10.1111/j.1460-9568.2006.05237.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The arachidonic acid-specific cytosolic phospholipase A(2) alpha (cPLA(2)alpha) has been implicated in the generation of neurological injuries. cPLA(2)alpha-dependent neurological injury has been postulated to be mediated through inflammatory and eicosanoid pathways. We determined if cPLA(2)alpha amplifies the injury of a non-inflammatory, excitotoxic stimulus by modifying a well-described toxicity assay to measure the toxicity of N-methyl-d-aspartate (NMDA) in the CA1 region of organotypic, mouse hippocampal cultures. Hippocampal cultures from wild-type and cPLA(2)alpha knockout mice were exposed to 5, 7.5 or 10 microm NMDA for 1 h. Toxicity was measured 23 h later. Cultures derived from cPLA(2)alpha(-/-) mice and cultures treated with the selective inhibitor AACOCF(3) were significantly protected from NMDA toxicity, as compared with wild-type cultures. To determine if cPLA(2)alpha-dependent toxicity is cyclooxygenase (COX)-2 dependent, COX-2 and PGE(2) levels were measured 7 and 25 h after NMDA treatment. NMDA treatment failed to induce COX-2 protein or increase PGE(2) in the culture media in either genotype at either time. In contrast, phorbol 12-myristate 13-acetate and ionophore treatment caused robust induction of COX-2 and PGE(2) in both genotypes. We conclude that cPLA(2)alpha may have a hitherto unrecognized direct effect on excitatory neurotoxicity, suggesting that cPLA(2)alpha inhibition is a therapeutic candidate for treatment of the early, excitotoxic injury observed in stroke.
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Affiliation(s)
- Ken M Brady
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins School of Medicine, Baltimore, MD, USA
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209
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Kunz A, Anrather J, Zhou P, Orio M, Iadecola C. Cyclooxygenase-2 does not contribute to postischemic production of reactive oxygen species. J Cereb Blood Flow Metab 2007; 27:545-51. [PMID: 16820798 DOI: 10.1038/sj.jcbfm.9600369] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We sought to determine whether reactive oxygen species (ROS) derived from cyclooxygenase-2 (COX-2) are involved in ischemic brain injury. Focal cerebral ischemia was induced by transient middle cerebral artery occlusion in C57BL/6 mice. The time course of neocortical ROS production was assessed in vivo using hydroethidine as a marker. The same brain sections were used for infarct volume measurements. Transient middle cerebral artery occlusion led to a biphasic increase in ROS production with peaks 2 and 72 h after reperfusion. The COX-2 inhibitor NS398 (10 mg/kg) attenuated the production of COX-2-derived prostaglandin E(2) and reduced brain injury, but did not affect ROS production at 2 and 72 h. Similarly, ROS production was not reduced in COX-2-null mice. In contrast, ROS production and brain injury were reduced in mice lacking the nox2 subunit of the superoxide-producing enzyme nicotinamide adenine dinucleotide phosphate (reduced form) oxidase. The data suggest that COX-2 is not a major source of oxygen radicals after cerebral ischemia and raise the possibility that other COX-2 reaction products, including prostanoids or nonoxygen-based radicals, mediate the COX-2-dependent component of the injury.
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Affiliation(s)
- Alexander Kunz
- Division of Neurobiology, Weill Medical College of Cornell University, New York, NY 10021, USA
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210
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Wang Q, Tang XN, Yenari MA. The inflammatory response in stroke. J Neuroimmunol 2007; 184:53-68. [PMID: 17188755 PMCID: PMC1868538 DOI: 10.1016/j.jneuroim.2006.11.014] [Citation(s) in RCA: 888] [Impact Index Per Article: 52.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2006] [Accepted: 11/17/2006] [Indexed: 12/17/2022]
Abstract
Recent works in the area of stroke and brain ischemia has demonstrated the significance of the inflammatory response accompanying necrotic brain injury. Acutely, this response appears to contribute to ischemic pathology, and anti-inflammatory strategies have become popular. This chapter will discuss the current knowledge of the contribution of systemic and local inflammation in experimental stroke. It will review the role of specific cell types including leukocytes, endothelium, glia, microglia, the extracellular matrix and neurons. Intracellular inflammatory signaling pathways such as nuclear factor kappa beta and mitogen-activated protein kinases, and mediators produced by inflammatory cells such as cytokines, chemokines, reactive oxygen species and arachidonic acid metabolites will be reviewed as well as the potential for therapy in stroke and hypoxic-ischemic injury.
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Affiliation(s)
- Qing Wang
- Department of Neurology, University of California, San Francisco and the San Francisco Veterans Affairs Medical Center, San Francisco, CA
- Department of Anesthesia, Stanford University School of Medicine, Stanford, CA
| | - Xian Nan Tang
- Department of Neurology, University of California, San Francisco and the San Francisco Veterans Affairs Medical Center, San Francisco, CA
- Department of Anesthesia, Stanford University School of Medicine, Stanford, CA
| | - Midori A. Yenari
- Department of Neurology, University of California, San Francisco and the San Francisco Veterans Affairs Medical Center, San Francisco, CA
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211
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Esposito E, Di Matteo V, Benigno A, Pierucci M, Crescimanno G, Di Giovanni G. Non-steroidal anti-inflammatory drugs in Parkinson's disease. Exp Neurol 2007; 205:295-312. [PMID: 17433296 DOI: 10.1016/j.expneurol.2007.02.008] [Citation(s) in RCA: 172] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2006] [Revised: 02/05/2007] [Accepted: 02/13/2007] [Indexed: 01/04/2023]
Abstract
Parkinson's disease (PD) is known to be a chronic and progressive neurodegenerative disease caused by a selective degeneration of dopaminergic (DAergic) neurons in the substantia nigra pars compacta (SNc). A large body of experimental evidence indicates that the factors involved in the pathogenesis of this disease are several, occurring inside and outside the DAergic neuron. Recently, the role of the neuron-glia interaction and the inflammatory process, in particular, has been the object of intense study by the research community. It seems to represent a new therapeutic approach opportunity for this neurological disorder. Indeed, it has been demonstrated that the cyclooxygenase type 2 (COX-2) is up-regulated in SNc DAergic neurons in both PD patients and animal models of PD and, furthermore, non-steroidal anti-inflammatory drugs (NSAIDs) pre-treatment protects against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) or 6 hydroxydopamine (6-OHDA)-induced nigro-striatal dopamine degeneration. Moreover, recent epidemiological studies have revealed that the risk of developing PD is reduced in humans who make therapeutical use of NSAIDs. Consequently, it is hypothesized that they might delay or prevent the onset of PD. However, whether or not these common drugs may also be of benefit to those individuals who already have Parkinson's disease has not as yet been shown. In this paper, evidence relating to the protective effects of aspirin or other NSAIDs on DAergic neurons in animal models of Parkinson's disease will be discussed. In addition, the pharmacological mechanisms by which these molecules can exert their neuroprotective effects will be reviewed. Finally, epidemiological data exploring the effectiveness of NSAIDs in the prevention of PD and their possible use as adjuvants in the therapy of this neurodegenerative disease will also be examined.
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Affiliation(s)
- Ennio Esposito
- Istituto di Ricerche Farmacologiche Mario Negri, Consorzio Mario Negri Sud, Santa Maria Imbaro (Chieti), Italy
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212
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Abstract
In acute stroke, neuronal apoptosis and inflammation are considered to be important mechanisms on the road to tissue loss and neurological deficit. Both apoptosis and inflammation depend on gene transcription. We have identified a signalling pathway that regulates transcription of genes involved in apoptosis and inflammation. In a mouse model of focal cerebral ischaemia, there is an induction of the cytokine TWEAK (tumour necrosis factor-like weak inducer of apoptosis) and its membrane receptor Fn14. TWEAK promotes neuronal cell death and activates the transcription factor NF-kappaB (nuclear factor kappaB) through the upstream kinase IKK [IkappaB (inhibitory kappaB) kinase]. In vivo, IKK is activated in neurons. Neuron-specific deletion of the subunit IKK2 or inhibition of IKK activity reduced the infarct size and neuronal cell loss. A pharmacological inhibitor of IKK also showed neuroprotective properties. IKK-dependent ischaemic brain damage is likely to be mediated by NF-kappaB, because neuron-specific inhibition of NF-kappaB through transgenic expression of the NF-kappaB superrepressor was found to reduce the infarct size. In summary, there is evidence that IKK/NF-kappaB signalling contributes to ischaemic brain damage and may provide suitable drug targets for the treatment of stroke.
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Affiliation(s)
- M Schwaninger
- Department of Neurology, University of Heidelberg, Im Neuenheimer Feld 400, 69120 Heidelberg, Germany.
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213
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Ahmad M, Ahmad AS, Zhuang H, Maruyama T, Narumiya S, Doré S. Stimulation of prostaglandin E2-EP3 receptors exacerbates stroke and excitotoxic injury. J Neuroimmunol 2007; 184:172-9. [PMID: 17275922 PMCID: PMC1914218 DOI: 10.1016/j.jneuroim.2006.12.012] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2006] [Revised: 11/22/2006] [Accepted: 12/15/2006] [Indexed: 11/26/2022]
Abstract
The effect of PGE(2) EP3 receptors on injury size was investigated following cerebral ischemia and induced excitotoxicity in mice. Treatment with the selective EP3 agonist ONO-AE-248 significantly and dose-dependently increased infarct size in the middle cerebral artery occlusion model. In a separate experiment, pretreatment with ONO-AE-248 exacerbated the lesion caused by N-methyl-d-aspartic acid-induced acute excitotoxicity. Conversely, genetic deletion of EP3 provided protection against N-methyl-d-aspartic acid-induced toxicity. The results suggest that PGE(2), by stimulating EP3 receptors, can contribute to the toxicity associated with cyclooxygenase and that antagonizing this receptor could be used therapeutically to protect against stroke- and excitotoxicity-induced brain damage.
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MESH Headings
- Animals
- Body Temperature/drug effects
- Brain Infarction/etiology
- Brain Infarction/pathology
- Brain Injuries/chemically induced
- Brain Injuries/pathology
- Brain Injuries/physiopathology
- Cerebrovascular Circulation/drug effects
- Dinoprostone/adverse effects
- Dinoprostone/analogs & derivatives
- Dose-Response Relationship, Drug
- Drug Synergism
- Infarction, Middle Cerebral Artery/pathology
- Infarction, Middle Cerebral Artery/physiopathology
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- N-Methylaspartate
- Receptors, Prostaglandin E/antagonists & inhibitors
- Receptors, Prostaglandin E/deficiency
- Receptors, Prostaglandin E/physiology
- Receptors, Prostaglandin E, EP3 Subtype
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Affiliation(s)
- Muzamil Ahmad
- Department of Anesthesiology/Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, Maryland
| | - Abdullah Shafique Ahmad
- Department of Anesthesiology/Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, Maryland
| | - Hean Zhuang
- Department of Anesthesiology/Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, Maryland
| | - Takayuki Maruyama
- Discovery Research Institute I, Ono Pharmaceutical Co. Ltd., Mishima-gun, Osaka, Japan
| | - Shuh Narumiya
- Department of Pharmacology, Kyoto University Faculty of Medicine, Kyoto 606-8501, Japan
| | - Sylvain Doré
- Department of Anesthesiology/Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, Maryland
- Department of Neuroscience, Johns Hopkins University, School of Medicine, Baltimore, Maryland
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214
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Candelario-Jalil E, González-Falcón A, García-Cabrera M, León OS, Fiebich BL. Post-ischaemic treatment with the cyclooxygenase-2 inhibitor nimesulide reduces blood-brain barrier disruption and leukocyte infiltration following transient focal cerebral ischaemia in rats. J Neurochem 2007; 100:1108-20. [PMID: 17176264 DOI: 10.1111/j.1471-4159.2006.04280.x] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Several studies suggest that cyclooxygenase (COX)-2 plays a pivotal role in the progression of ischaemic brain damage. In the present study, we investigated the effects of selective inhibition of COX-2 with nimesulide (12 mg/kg) and selective inhibition of COX-1 with valeryl salicylate (VAS, 12-120 mg/kg) on prostaglandin E(2) (PGE(2)) levels, myeloperoxidase (MPO) activity, Evans blue (EB) extravasation and infarct volume in a standardized model of transient focal cerebral ischaemia in the rat. Post-ischaemic treatment with nimesulide markedly reduced the increase in PGE(2) levels in the ischaemic cerebral cortex 24 h after stroke and diminished infarct size by 48% with respect to vehicle-treated animals after 3 days of reperfusion. Furthermore, nimesulide significantly attenuated the blood-brain barrier (BBB) damage and leukocyte infiltration (as measured by EB leakage and MPO activity, respectively) seen at 48 h after the initial ischaemic episode. These studies provide the first experimental evidence that COX-2 inhibition with nimesulide is able to limit BBB disruption and leukocyte infiltration following transient focal cerebral ischaemia. Neuroprotection afforded by nimesulide is observed even when the treatment is delayed until 6 h after the onset of ischaemia, confirming a wide therapeutic window of COX-2 inhibitors in experimental stroke. On the contrary, selective inhibition of COX-1 with VAS had no significant effect on the evaluated parameters. These data suggest that COX-2 activity, but not COX-1 activity, contributes to the progression of focal ischaemic brain injury, and that the beneficial effects observed with non-selective COX inhibitors are probably associated to COX-2 rather than to COX-1 inhibition.
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Affiliation(s)
- Eduardo Candelario-Jalil
- Neurochemistry Research Group, Department of Psychiatry, University of Freiburg Medical School, Freiburg, Germany.
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Mehta SL, Manhas N, Raghubir R. Molecular targets in cerebral ischemia for developing novel therapeutics. ACTA ACUST UNITED AC 2007; 54:34-66. [PMID: 17222914 DOI: 10.1016/j.brainresrev.2006.11.003] [Citation(s) in RCA: 528] [Impact Index Per Article: 31.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2006] [Revised: 11/09/2006] [Accepted: 11/10/2006] [Indexed: 11/20/2022]
Abstract
Cerebral ischemia (stroke) triggers a complex series of biochemical and molecular mechanisms that impairs the neurologic functions through breakdown of cellular integrity mediated by excitotoxic glutamatergic signalling, ionic imbalance, free-radical reactions, etc. These intricate processes lead to activation of signalling mechanisms involving calcium/calmodulin-dependent kinases (CaMKs) and mitogen-activated protein kinases (MAPKs) such as extracellular signal-regulated kinase (ERK), p38, and c-Jun N-terminal kinase (JNK). The distribution of these transducers bring them in contact with appropriate molecular targets leading to altered gene expression, e.g. ERK and JNK mediated early gene induction, responsible for activation of cell survival/damaging mechanisms. Moreover, inflammatory reactions initiated at the neurovascular interface and alterations in the dynamic communication between the endothelial cells, astrocytes and neurons are thought to substantially contribute to the pathogenesis of the disease. The damaging mechanisms may proceed through rapid nonspecific cell lysis (necrosis) or by active form of cell demise (apoptosis or necroptosis), depending upon the severity and duration of the ischemic insult. A systematic understanding of these molecular mechanisms with prospect of modulating the chain of events leading to cellular survival/damage may help to generate the potential strategies for neuroprotection. This review briefly covers the current status on the molecular mechanisms of stroke pathophysiology with an endeavour to identify potential molecular targets such as targeting postsynaptic density-95 (PSD-95)/N-methyl-d-aspartate (NMDA) receptor interaction, certain key proteins involved in oxidative stress, CaMKs and MAPKs (ERK, p38 and JNK) signalling, inflammation (cytokines, adhesion molecules, etc.) and cell death pathways (caspases, Bcl-2 family proteins, poly (ADP-ribose) polymerase-1 (PARP-1), apoptosis-inducing factor (AIF), inhibitors of apoptosis proteins (IAPs), heat shock protein 70 (HSP70), receptor interacting protein (RIP), etc., besides targeting directly the genes itself. However, selecting promising targets from various signalling cascades, for drug discovery and development is very challenging, nevertheless such novel approaches may lead to the emergence of new avenues for therapeutic intervention in cerebral ischemia.
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Affiliation(s)
- Suresh L Mehta
- Division of Pharmacology, Central Drug Research Institute, Chatter Manzil Palace, POB-173, Lucknow-226001, India
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216
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LaManna JC, Sun X, Ivy AD, Ward NL. Is cycloxygenase-2 (COX-2) a major component of the mechanism responsible for microvascular remodeling in the brain? ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2007; 578:297-303. [PMID: 16927708 DOI: 10.1007/0-387-29540-2_47] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Affiliation(s)
- Joseph C LaManna
- Department of Anatomy, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA
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217
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Pascual M, Blanco AM, Cauli O, Miñarro J, Guerri C. Intermittent ethanol exposure induces inflammatory brain damage and causes long-term behavioural alterations in adolescent rats. Eur J Neurosci 2007; 25:541-50. [PMID: 17284196 DOI: 10.1111/j.1460-9568.2006.05298.x] [Citation(s) in RCA: 281] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Adolescent brain development seems to be important for the maturation of brain structures and behaviour. Intermittent binge ethanol drinking is common among adolescents, and this type of drinking can induce brain damage. Because we have demonstrated that chronic ethanol treatment induces inflammatory processes in the brain, we investigate whether intermittent ethanol intoxication enhances cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) in adolescent rats, and whether these mediators induce brain damage and cause permanent cognitive dysfunctions. Adolescent rats were exposed to ethanol (3.0 g/kg) for two consecutive days at 48-h intervals over 14 days. Levels of COX-2, iNOS and cell death were assessed in the neocortex, hippocampus and cerebellum 24 h after the final ethanol administration. The following day or 20 days after the final injection (adult stage), animals were tested for different behavioural tests (conditional discrimination learning, rotarod, object recognition, beam-walking performance) to assess cognitive and motor functions. Our results show that intermittent ethanol intoxication upregulates COX-2 and iNOS levels, and increases cell death in the neocortex, hippocampus and cerebellum. Furthermore, animals treated with ethanol during adolescence exhibited behavioural deficits that were evident at the end of ethanol treatments and at the adult stage. Administration of indomethacin, a COX-2 inhibitor, abolishes the induction of COX-2 and iNOS expression and cell death, preventing ethanol-induced behavioural deficits. These findings indicate that binge pattern exposure to ethanol during adolescence induces brain damage by inflammatory processes and causes long-lasting neurobehavioural consequences. Accordingly, administering indomethacin protects against ethanol-induced brain damage and prevents detrimental ethanol effects on cognitive and motor processes.
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Affiliation(s)
- Maria Pascual
- Department of Cellular Pathology, Centro de Investigación Príncipe Felipe, Avda. Autopista del Saler, 16. 46013-Valencia, Spain
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218
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Sinn DI, Lee ST, Chu K, Jung KH, Song EC, Kim JM, Park DK, Kim M, Roh JK. Combined neuroprotective effects of celecoxib and memantine in experimental intracerebral hemorrhage. Neurosci Lett 2007; 411:238-42. [PMID: 17123715 DOI: 10.1016/j.neulet.2006.10.050] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2006] [Revised: 10/13/2006] [Accepted: 10/13/2006] [Indexed: 11/18/2022]
Abstract
Memantine, a N-methyl-D-aspartate (NMDA) receptor antagonist, inhibits hematoma expansion and celecoxib, a selective cyclooxygenase-2 (COX-2) inhibitor, reduces perihematomal inflammation in intracerebral hemorrhage. We examined whether the combination treatment has additive effects in experimental intracerebral hemorrhage (ICH). ICH was induced using stereotaxic infusion of collagenase into brains of adult rats. After the induction of ICH, rats were treated with intraperitoneal injection of memantine (20 mg/kg), celecoxib (20 mg/kg) or both agents. Only vehicles were administrated in rats of the control group. Results showed that the combination treatment of memantine and celecoxib reduced both hematoma volume and brain edema. Combination treatment also induced the better functional recovery with further attenuation of cerebral inflammation and apoptosis compared to the control group. When compared to the single agent groups, the combination treatment showed better effects in neuroprotection and anti-inflammation. These results suggest the feasible combined application of memantine and celecoxib in ICH treatment.
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Affiliation(s)
- Dong-In Sinn
- Stroke & Neural Stem Cell Laboratory in the Clinical Research Institute, Stem Cell Research Center, Department of Neurology, Seoul National University Hospital, Seoul, South Korea
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219
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Kelsen J, Kjær K, Chen G, Pedersen M, Røhl L, Frøkiær J, Nielsen S, Nyengaard JR, Rønn LCB. Parecoxib is neuroprotective in spontaneously hypertensive rats after transient middle cerebral artery occlusion: a divided treatment response? J Neuroinflammation 2006; 3:31. [PMID: 17150094 PMCID: PMC1764728 DOI: 10.1186/1742-2094-3-31] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2006] [Accepted: 12/06/2006] [Indexed: 02/05/2023] Open
Abstract
Background Anti-inflammatory treatment affects ischemic damage and neurogenesis in rodent models of cerebral ischemia. We investigated the potential benefit of COX-2 inhibition with parecoxib in spontaneously hypertensive rats (SHRs) subjected to transient middle cerebral artery occlusion (tMCAo). Methods Sixty-four male SHRs were randomized to 90 min of intraluminal tMCAo or sham surgery. Parecoxib (10 mg/kg) or isotonic saline was administered intraperitoneally (IP) during the procedure, and twice daily thereafter. Nineteen animals were euthanized after 24 hours, and each hemisphere was examined for mRNA expression of pro-inflammatory cytokines and COX enzymes by quantitative RT-PCR. Twenty-three tMCAo animals were studied with diffusion and T2 weighted MRI within the first 24 hours, and ten of the SHRs underwent follow-up MRI six days later. Thirty-three SHRs were given 5-bromo-2'-deoxy-uridine (BrdU) twice daily on Day 4 to 7 after tMCAo. Animals were euthanized on Day 8 and the brains were studied with free-floating immunohistochemistry for activated microglia (ED-1), hippocampal granule cell BrdU incorporation, and neuronal nuclei (NeuN). Infarct volume estimation was done using the 2D nucleator and Cavalieri principle on NeuN-stained coronal brain sections. The total number of BrdU+ cells in the dentate gyrus (DG) of the hippocampus was estimated using the optical fractionator. Results We found a significant reduction in infarct volume in parecoxib treated animals one week after tMCAo (p < 0.03). Cortical ADC values in the parecoxib group were markedly less increased on Day 8 (p < 0.01). Interestingly, the parecoxib treated rats were segregated into two subgroups, suggesting a responder vs. non-responder phenomenon. We found indications of mRNA up-regulation of IL-1β, IL-6, TNF-α and COX-2, whereas COX-1 remained unaffected. Hippocampal granule cell BrdU incorporation was not affected by parecoxib treatment. Presence of ED-1+ activated microglia in the hippocampus was related to an increase in BrdU uptake in the DG. Conclusion IP parecoxib administration during tMCAo was neuroprotective, as evidenced by a large reduction in mean infarct volume and a lower cortical ADC increment. Increased pro-inflammatory cytokine mRNA levels and hippocampal granule cell BrdU incorporation remained unaffected.
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Affiliation(s)
- Jesper Kelsen
- The Water and Salt Research Centre, University of Aarhus, DK-8000 Aarhus C, Denmark
- Department of Neurosurgery NK, University Hospital of Aarhus, Noerrebrogade 44, DK-8000 Aarhus C, Denmark
- Institute of Clinical Medicine, University Hospital of Aarhus, Brendstrupgaardsvej 100, DK-8200 Aarhus N, Denmark
| | - Katrine Kjær
- NEUROSEARCH A/S, Pederstrupvej 93, DK-2750 Ballerup, Denmark
| | - Gang Chen
- Institute of Clinical Medicine, University Hospital of Aarhus, Brendstrupgaardsvej 100, DK-8200 Aarhus N, Denmark
- MR Research Centre, University Hospital of Aarhus, Brendstrupgaardsvej 100, DK-8200 Aarhus N, Denmark
| | - Michael Pedersen
- Institute of Clinical Medicine, University Hospital of Aarhus, Brendstrupgaardsvej 100, DK-8200 Aarhus N, Denmark
- MR Research Centre, University Hospital of Aarhus, Brendstrupgaardsvej 100, DK-8200 Aarhus N, Denmark
| | - Lisbeth Røhl
- Department of Radiology, University Hospital of Aarhus, Noerrebrogade 44, DK-8000 Aarhus C, Denmark
| | - Jørgen Frøkiær
- The Water and Salt Research Centre, University of Aarhus, DK-8000 Aarhus C, Denmark
- Institute of Clinical Medicine, University Hospital of Aarhus, Brendstrupgaardsvej 100, DK-8200 Aarhus N, Denmark
| | - Søren Nielsen
- The Water and Salt Research Centre, University of Aarhus, DK-8000 Aarhus C, Denmark
- Institute of Anatomy, University of Aarhus, DK-8000 Aarhus C, Denmark
| | - Jens R Nyengaard
- Institute of Clinical Medicine, University Hospital of Aarhus, Brendstrupgaardsvej 100, DK-8200 Aarhus N, Denmark
- Stereology and EM Research Laboratory and MIND Center, University of Aarhus, DK-8000 Aarhus C, Denmark
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Abstract
This chapter will discuss the current knowledge of the contribution of systemic and local inflammation in acute and sub-chronic stages of experimental stroke in both the adult and neonate. It will review the role of specific cell types and interactions among blood cells, endothelium, glia, microglia, the extracellular matrix and neurons - cumulatively called "neurovascular unit" - in stroke induction and evolution. Intracellular inflammatory signaling pathways such as nuclear factor kappa beta and mitogen-activated protein kinases, and mediators produced by inflammatory cells such as cytokines, chemokines, reactive oxygen species and arachidonic acid metabolites, as well as the modifying role of age on these mechanisms, will be reviewed as well as the potential for therapy in stroke and hypoxic-ischemic injury.
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221
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Ding Q, Wei EQ, Zhang YJ, Zhang WP, Chen Z. Cysteinyl leukotriene receptor 1 is involved in N-methyl-D-aspartate-mediated neuronal injury in mice. Acta Pharmacol Sin 2006; 27:1526-36. [PMID: 17112405 DOI: 10.1111/j.1745-7254.2006.00438.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
AIM To determine whether cysteinyl leukotriene receptor 1 (CysLT1 receptor) is involved in N-methyl-D-aspartate (NMDA)-induced excitotoxic injury in the mouse brain. METHODS Brain injury was induced by NMDA microinjection (50-150 nmol in 0.5 microL) into the cerebral cortex. The changes in CysLT1 receptor expression 24 h after NMDA injection and the effects of a CysLT1 receptor antagonist, pranlukast (0.01 and 0.1 mg/kg), an NMDA receptor antagonist, ketamine (30 mg/kg), and an antioxidant, edaravone (9 mg/kg) were observed. RESULTS In the NMDA-injured brain, the CysLT1 receptor mRNA, and protein expression were upregulated, and the receptor was mainly localized in the neurons and not in the astrocytes. Pranlukast, ketamine and edaravone decreased NMDA-induced injury; pranlukast (0.1 mg/kg) and ketamine inhibited the upregulated expression of the CysLT1 receptor. CONCLUSION CysLT1 receptor expression in neurons is upregulated after NMDA injection, and NMDA-induced responses are inhibited by CysLT1 receptor antagonists, indicating that the increased CysLT1 receptor is involved in NMDA excitotoxicity.
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Affiliation(s)
- Qian Ding
- Department of Pharmacology, School of Medicine, Zhejiang University, Hangzhou 310058, China.
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222
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Wang X. Investigational anti-inflammatory agents for the treatment of ischaemic brain injury. Expert Opin Investig Drugs 2006; 14:393-409. [PMID: 15882116 DOI: 10.1517/13543784.14.4.393] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Stroke is the third leading cause of death and the leading cause of disability in Western countries. To date, only approximately 2% of stroke patients are eligible for thrombolysis treatment with recombinant tissue plasminogen activator. The very limited options available for stroke treatment and recent disappointing clinical trials in stroke call for novel therapeutic approaches. Inflammation represents one of the key pathophysiological mechanisms for the progression of ischaemic stroke. Recent advances in preclinical models of stroke using investigational small molecular antagonists, neutralising antibodies/proteins or genetically altered gene functions against various inflammatory mediators suggest a great therapeutic potential of anti-inflammation for ischaemic stroke. The scope of the present review is to update the evidence for a role of inflammatory pathways in stroke and to summarise the investigational drugs currently available both in preclinical and clinical development for potential treatment of ischaemic stroke.
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Affiliation(s)
- Xinkang Wang
- Bristol-Myers Squibb Company, Discovery Biology, 311 Pennington-Rocky Hill Road, Pennington, NJ 08534, USA.
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223
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Hewett SJ, Bell SC, Hewett JA. Contributions of cyclooxygenase-2 to neuroplasticity and neuropathology of the central nervous system. Pharmacol Ther 2006; 112:335-57. [PMID: 16750270 DOI: 10.1016/j.pharmthera.2005.04.011] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2005] [Accepted: 04/19/2005] [Indexed: 01/08/2023]
Abstract
Cyclooxygenase (COX) enzymes, or prostaglandin-endoperoxide synthases (PTGS), are heme-containing bis-oxygenases that catalyze the first committed reaction in metabolism of arachidonic acid (AA) to the potent lipid mediators, prostanoids and thromboxanes. Two isozymes of COX enzymes (COX-1 and COX-2) have been identified to date. This review will focus specifically on the neurobiological and neuropathological consequences of AA metabolism via the COX-2 pathway and discuss the potential therapeutic benefit of COX-2 inhibition in the setting of neurological disease. However, given the controversy surrounding the use of COX-2 selective inhibitors with respect to cardiovascular health, it will be important to move beyond COX to identify which down-stream effectors are responsible for the deleterious and/or potentially protective effects of COX-2 activation in the setting of neurological disease. Important advances toward this goal are highlighted herein. Identification of unique effectors in AA metabolism could direct the development of new therapeutics holding significant promise for the prevention and treatment of neurological disorders.
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Affiliation(s)
- Sandra J Hewett
- Department of Neuroscience MC3401, University of Connecticut Health Center, 263 Farmington Avenue, Farmington, CT 06030, USA.
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224
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Abstract
Lipids are essential components of plasma- and organelle-membranes, not only providing a frame for embedded proteins (e.g., receptors and ion channels) but also functioning as reservoirs for lipid mediators. Increasing evidence indicates that bioactive lipids such as eicosanoids, endocannabinoids, and lysophospholipids serve as intercellular and intracellular signaling molecules participating in physiological and pathological functions in the brain. The discovery of some of these lipid receptors and novel lipid signaling mediators has sparked an intense interest in lipidomic neurobiology research. Classic prostaglandins (PGD(2), PGE(2), PGF(2alpha), PGI(2), and TXA(2)), catalyzed by cyclooxygenases (COX), are synthesized from arachidonic acid (AA). Experimental studies demonstrate that prostaglandin E(2) (PGE(2)), mainly derived from the COX-2 reaction, is an important mediator, acting as a retrograde messenger via a presynaptic PGE(2) subtype 2 receptor (EP(2)) in modulation of synaptic events. Novel prostaglandins (prostaglandin glycerol esters and prostaglandin ethanolamides) are COX-2 oxidative metabolites of endogenous cannabinoids (2-arachidonyl glycerol and arachidonyl ethanolamide). Recent evidence suggests that these new types of prostaglandins are likely novel signaling mediators involved in synaptic transmission and plasticity. This means that COX- 2 plays a central role in metabolisms of AA and endocannabinoids (eCBs) and productions of AA- and eCB- derived prostaglandins. Thus, in the present review article, the authors will mainly discuss COX-2 regulation of prostaglandin signaling in modulation of hippocampal synaptic transmission and plasticity.
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Affiliation(s)
- Nan Sang
- Neuroscience Center of Excellence, School of Medicine, Louisiana State University Health Sciences Center, 2020 Gravier Street, New Orleans, LA 70112, USA
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Wang ML, Huang XJ, Fang SH, Yuan YM, Zhang WP, Lu YB, Ding Q, Wei EQ. Leukotriene D4 induces brain edema and enhances CysLT2 receptor-mediated aquaporin 4 expression. Biochem Biophys Res Commun 2006; 350:399-404. [PMID: 17010308 DOI: 10.1016/j.bbrc.2006.09.057] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2006] [Accepted: 09/12/2006] [Indexed: 12/29/2022]
Abstract
Cysteinyl leukotrienes (including LTC(4), LTD(4), and LTE(4)), potent inflammatory mediators, can induce brain-blood barrier (BBB) disruption and brain edema. These reactions are mediated by their receptors, CysLT(1) and CysLT(2) receptors. On the other hand, aquaporin 4 (AQP4) primarily modulates brain water homeostasis and edema after various injuries. Here, we aimed to determine whether AQP4 is involved in LTD(4)-induced brain edema. LTD(4) (1ng in 0.5mul PBS) microinjection into the cortex increased endogenous IgG exudation (BBB disruption) and water content (brain edema), and enhanced AQP4 expression in mouse brain. The selective CysLT(1) receptor antagonist pranlukast inhibited the IgG exudation, but not the increased water content and AQP4 expression induced by LTD(4). In the cultured rat astrocytes, LTD(4) (10(-9)-10(-7)M, for 24h) similarly enhanced AQP4 expression. The enhanced AQP4 expression was inhibited by Bay u9773, a non-selective CysLT(1)/CysLT(2) receptor antagonist, but not by pranlukast. LTD(4) (10(-9)-10(-7)M) also induced the mRNA expression of CysLT(2) (not CysLT(1)) receptor in astrocytes. These results indicate that LTD(4) modulates brain edema; CysLT(1) receptor mediates vasogenic edema while CysLT(2) receptor may mediate cytotoxic edema via up-regulating AQP4 expression.
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Affiliation(s)
- Meng-Ling Wang
- Department of Pharmacology and Institute of Neuroscience, School of Medicine, Zhejiang University, 388, Yu Hang Tang Road, Hangzhou 310058, China
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226
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Hewett SJ, Silakova JM, Hewett JA. Oral treatment with rofecoxib reduces hippocampal excitotoxic neurodegeneration. J Pharmacol Exp Ther 2006; 319:1219-24. [PMID: 16963621 DOI: 10.1124/jpet.106.109876] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The purpose of this study was to determine whether the selective cyclooxygenase-2 (COX-2) inhibitor rofecoxib [4-[4-(methylsulfonyl)phenyl]-3-phenyl-2(5H)-furanone] could effectively prevent hippocampal neuronal injury in an animal model of excitotoxic neurodegeneration. COX-2 protein levels increased between 3 and 6 h, peaked at 12 h, and declined to near baseline levels 24 h after injection of N-methyl-d-aspartate (NMDA; 18 nmol) into the CA1 region of the left hippocampus. Mice that were fed ad libitum a control rodent diet for 4 days before and 3 days after injection of NMDA demonstrated marked neuronal loss in the primary cell layers of the ipsilateral CA1, CA3, and dentate gyrus (50, 30, and 20% cell loss, respectively). This injury was potently and dose-dependently reduced by feeding animals a diet standardized to deliver 15 or 30 mg/kg rofecoxib per day. Neurodegeneration in the CA1 region was reduced by 30.1 +/- 5.6 and 51.5 +/- 9.0%, respectively; in the CA3 by 64.6 +/- 12.4 and 69.0 +/- 14.1%, respectively; and in the dentate gyrus by 47.8 +/- 15.2 and 58.0 +/- 18.2%, respectively. Moreover, rofecoxib chow slightly but significantly reduced injury-induced brain edema. These findings demonstrate that rofecoxib can ameliorate excitotoxic neuronal injury in vivo and, as such, may be a particularly promising pharmaceutical for the treatment of neurological diseases associated with overactivation of NMDA receptors.
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Affiliation(s)
- Sandra J Hewett
- Department of Neuroscience, Program in Cellular and Molecular Pharmacology, University of Connecticut School of Medicine, Farmington, Connecticut, USA.
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Zou LY, Cheung RTF, Liu S, Li G, Huang L. Melatonin reduces infarction volume in a photothrombotic stroke model in the wild-type but not cyclooxygenase-1-gene knockout mice. J Pineal Res 2006; 41:150-6. [PMID: 16879321 DOI: 10.1111/j.1600-079x.2006.00349.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Cyclooxygenase (COX)-2 plays a harmful role in cerebral ischemic/reperfusion injury, but the role of COX-1 is uncertain. In the present study, cerebral infarct was induced by photothrombosis. Intraperitoneal injections of melatonin at 15 g/kg or its vehicle were made at 0.5 hr before stroke and 24 and 48 hr after stroke. Cerebral blood flow (CBF) in the penumbra was monitored during stroke using a laser Doppler flowmeter. Sensorimotor behavior was evaluated using the turning in an alley and falling from a pole tests at 1 hr before stroke and 24 and 48 hr after stroke. Infarct volume was determined from the T2-weighted magnetic resonance images at 72 hr after stroke. During the first 15 min of stroke, CBF decreased in the penumbra in both homozygous COX-1-gene knockout and wild-type mice. Melatonin treatment improved the penumbral CBF in the wild-type mice. Mild poststroke impairment in sensorimotor behavior was detected by the turning in an alley test in which the COX-1-gene knockout mice performed better. Melatonin treatment did not affect the poststroke sensorimotor behavior. The relative infarct volume at 72 hr after stroke was 8.1% and 8.4% in the COX-1-gene knockout and wild-type mice, respectively. Melatonin treatment reduced the relative infarct volume to 6.3% in the latter but not in the former (8.2%). Thus, COX-1-gene knockout does not affect the brain's susceptibility to photothrombotic stroke. Melatonin treatment reduces infarct size in the wild-type mice following photothrombotic stroke partly via maintenance of penumbral CBF in which the COX-1-gene may play a role.
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Affiliation(s)
- Liang Yu Zou
- Division of Neurology, University Department of Medicine, The University of Hong Kong, Hong Kong
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Phillis JW, Horrocks LA, Farooqui AA. Cyclooxygenases, lipoxygenases, and epoxygenases in CNS: Their role and involvement in neurological disorders. ACTA ACUST UNITED AC 2006; 52:201-43. [PMID: 16647138 DOI: 10.1016/j.brainresrev.2006.02.002] [Citation(s) in RCA: 266] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2005] [Revised: 02/23/2006] [Accepted: 02/24/2006] [Indexed: 01/01/2023]
Abstract
Three enzyme systems, cyclooxygenases that generate prostaglandins, lipoxygenases that form hydroxy derivatives and leukotrienes, and epoxygenases that give rise to epoxyeicosatrienoic products, metabolize arachidonic acid after its release from neural membrane phospholipids by the action of phospholipase A(2). Lysophospholipids, the other products of phospholipase A(2) reactions, are either reacylated or metabolized to platelet-activating factor. Under normal conditions, these metabolites play important roles in synaptic function, cerebral blood flow regulation, apoptosis, angiogenesis, and gene expression. Increased activities of cyclooxygenases, lipoxygenases, and epoxygenases under pathological situations such as ischemia, epilepsy, Alzheimer's disease, Parkinson disease, amyotrophic lateral sclerosis, and Creutzfeldt-Jakob disease produce neuroinflammation involving vasodilation and vasoconstriction, platelet aggregation, leukocyte chemotaxis and release of cytokines, and oxidative stress. These are closely associated with the neural cell injury which occurs in these neurological conditions. The metabolic products of docosahexaenoic acid, through these enzymes, generate a new class of lipid mediators, namely docosatrienes and resolvins. These metabolites antagonize the effect of metabolites derived from arachidonic acid. Recent studies provide insight into how these arachidonic acid metabolites interact with each other and other bioactive mediators such as platelet-activating factor, endocannabinoids, and docosatrienes under normal and pathological conditions. Here, we review present knowledge of the functions of cyclooxygenases, lipoxygenases, and epoxygenases in brain and their association with neurodegenerative diseases.
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Affiliation(s)
- John W Phillis
- Department of Physiology, School of Medicine, Wayne State University, Detroit, MI 48201, USA.
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229
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Yang MS, Ji KA, Jeon SB, Jin BK, Kim SU, Jou I, Joe E. Interleukin-13 enhances cyclooxygenase-2 expression in activated rat brain microglia: implications for death of activated microglia. THE JOURNAL OF IMMUNOLOGY 2006; 177:1323-9. [PMID: 16818793 DOI: 10.4049/jimmunol.177.2.1323] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Brain inflammation has recently attracted widespread interest because it is a risk factor for the onset and progression of brain diseases. In this study, we report that cyclooxygenase-2 (COX-2) plays a key role in the resolution of brain inflammation by inducing the death of microglia. We previously reported that IL-13, an anti-inflammatory cytokine, induced the death of activated microglia. These results revealed that IL-13 significantly enhanced COX-2 expression and production of PGE(2) and 15-deoxy-Delta(12,14)-PGJ(2) (15d-PGJ(2)) in LPS-treated microglia. Two other anti-inflammatory cytokines, IL-10 and TGF-beta, neither induced microglial death nor enhanced COX-2 expression or PGE(2) or 15d-PGJ(2) production. Therefore, we hypothesized that the effect of IL-13 on COX-2 expression may be linked to death of activated microglia. We found that COX-2 inhibitors (celecoxib and NS398) suppressed the death of microglia induced by a combination of LPS and IL-13 and that exogenous addition of PGE(2) and 15d-PGJ(2) induced microglial death. Agonists of EP2 (butaprost) and peroxisome proliferator-activated receptor gamma (ciglitazone) mimicked the effect of PGE(2) and 15d-PGJ(2), and an EP2 antagonist (AH6809) and a peroxisome proliferator-activated receptor gamma antagonist (GW9662) suppressed microglial death induced by LPS in combination with IL-13. In addition, IL-13 potentiated LPS-induced activation of JNK, and the JNK inhibitor SP600125 suppressed the enhancement of COX-2 expression and attenuated microglial death. Taken together, these results suggest that IL-13 enhanced COX-2 expression in LPS-treated microglia through the enhancement of JNK activation. Furthermore, COX-2 products, PGE(2) and 15d-PGJ(2), caused microglial death, which terminates brain inflammation.
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Affiliation(s)
- Myung-Soon Yang
- Department of Pharmacology, Ajou University School of Medicine, Suwon 442-721, Korea
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230
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Doré S. GPCR antagonists as an alternative to COX-2 inhibitors: a case for the PGE2 EP1 receptor. Trends Pharmacol Sci 2006; 27:458-60. [PMID: 16870271 DOI: 10.1016/j.tips.2006.07.001] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A recent article supports the concept that prostaglandin (PG)E(2) EP(1)-receptor antagonists reduce stroke severity and cell damage; could these agents become a substitute for cyclooxygenase (COX)-2 inhibitors? The total activity of COXs--rate-limiting enzymes of PGE(2) synthesis--increases following acute neurological insult. Drugs that offer the beneficial anti-inflammatory and neuroprotective effects of PGs but that limit the negative effects of COX-2 inhibition could provide the next generation of treatment for acute neuronal damage.
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Affiliation(s)
- Sylvain Doré
- Departments of Anesthesiology and Critical Care Medicine, and Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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231
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Ikeda-Matsuo Y, Ota A, Fukada T, Uematsu S, Akira S, Sasaki Y. Microsomal prostaglandin E synthase-1 is a critical factor of stroke-reperfusion injury. Proc Natl Acad Sci U S A 2006; 103:11790-5. [PMID: 16864802 PMCID: PMC1518807 DOI: 10.1073/pnas.0604400103] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Although augmented prostaglandin E(2) (PGE(2)) synthesis and accumulation have been demonstrated in the lesion sites of rodent transient focal ischemia models, the role of PGE(2) in neuronal survival has been controversial, showing both protective and toxic effects. Here we demonstrate the induction of microsomal PGE synthase 1 (mPGES-1), an inducible terminal enzyme for PGE(2) synthesis, in neurons, microglia, and endothelial cells in the cerebral cortex after transient focal ischemia. In mPGES-1 knockout (KO) mice, in which the postischemic PGE(2) production in the cortex was completely absent, the infarction, edema, apoptotic cell death, and caspase-3 activation in the cortex after ischemia were all reduced compared with those in wild-type (WT) mice. Furthermore, the behavioral neurological dysfunctions observed after ischemia in WT mice were significantly ameliorated in KO mice. The ameliorated symptoms observed in KO mice after ischemia were reversed to almost the same severity as WT mice by intracerebroventricular injection of PGE(2) into KO mice. Our observations suggest that mPGES-1 may be a critical determinant of postischemic neurological dysfunctions and a valuable therapeutic target for treatment of human stroke.
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Affiliation(s)
- Yuri Ikeda-Matsuo
- Laboratory of Pharmacology, School of Pharmaceutical Sciences, Kitasato University, Tokyo 108-8641, Japan.
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232
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Zhao Y, Patzer A, Herdegen T, Gohlke P, Culman J. Activation of cerebral peroxisome proliferator-activated receptors gamma promotes neuroprotection by attenuation of neuronal cyclooxygenase-2 overexpression after focal cerebral ischemia in rats. FASEB J 2006; 20:1162-75. [PMID: 16770015 DOI: 10.1096/fj.05-5007com] [Citation(s) in RCA: 145] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Up-regulation of cyclooxygenase (COX)-2 exacerbates neuronal injury after cerebral ischemia and contributes to neuronal cell death. The present study clarifies the function of cerebral peroxisome-proliferator-activated receptor(s) gamma (PPARgamma) in the expression of COX-2 in neurons of the rat brain after middle cerebral artery occlusion (MCAO) with reperfusion by immunohistochemistry, Western blot, and immunofluorescence staining. In peri-infarct cortical areas the PPARgamma was located in both microglia and neurons, whereas COX-2 was almost exclusively expressed in neurons. PPARgamma immunolabeling reached the peak 12 h after MCAO, whereas the number of COX-2 immunostained cells gradually rose and reached its peak at 48 h. Intracerebroventricular infusion of pioglitazone, an agonist of the PPARgamma, over a 5-day period before and 2 days after MCAO, reduced the infarct size, the expression of tumor necrosis factor alpha (TNF-alpha), COX-2, and the number of cells positively stained for COX-1 and COX-2 in the peri-infarct cortical regions. COX-2 induction was also attenuated in the ipsilateral but not in the contralateral hippocampus. In primary cortical neurons expressing the PPARgamma, pioglitazone suppressed COX-2 expression in response to oxidative stress. This protective effect was reversed after cotreatment with GW 9662, a selective antagonist of the PPARgamma, clearly demonstrating a PPARgamma-dependent mechanism. Our data provide evidence that activation of neuronal PPARgamma considerably contributes to neuroprotection by prevention of COX-2 up-regulation in vitro and in peri-infarct brain areas.
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Affiliation(s)
- Yi Zhao
- Institute of Pharmacology, University Hospital of Schleswig-Holstein, Campus Kiel Hospitalstrasse 4 24105 Kiel, Germany
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233
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Takemiya T, Maehara M, Matsumura K, Yasuda S, Sugiura H, Yamagata K. Prostaglandin E2 produced by late induced COX-2 stimulates hippocampal neuron loss after seizure in the CA3 region. Neurosci Res 2006; 56:103-10. [PMID: 16837093 DOI: 10.1016/j.neures.2006.06.003] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2006] [Revised: 06/01/2006] [Accepted: 06/01/2006] [Indexed: 01/18/2023]
Abstract
Injection of kainic acid (KA) into the brain causes severe seizures with hippocampal neuron loss. KA has been shown to immediately induce cyclooxygenase-2 (COX-2) expression in hippocampal neurons, indicating that neuronal COX-2 might be involved in neuronal death. In this study, however, we reveal that the delayed COX-2 induction in non-neuronal cells after KA injection plays an important role in hippocampal neuron loss rather than early COX-2 expression in neurons. We find that KA microinjection into the hemilateral hippocampus shows a later induction of COX-2 expression in non-neuronal cells, such as endothelial cells and astrocytes. In the KA-injected side, PGE2 concentration gradually increases and peaks at 24 h after injection, when non-neuronal COX-2 expression also peaks. When this delayed PGE2 elevation is prevented by selective COX-2 inhibitor NS398, it can block hippocampal cell death. Moreover, COX-2 knockout mice are also resistant to neuronal death after KA treatment. These findings indicate that delayed PGE2 production by non-neuronal COX-2 may facilitate neuronal death after seizure. Inhibition of COX-2 to an extent similar to PGE2 elevation after onset of seizure may be useful to prevent neuronal death.
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Affiliation(s)
- Takako Takemiya
- Department of Neuropharmacology, Tokyo Metropolitan Institute for Neuroscience, Fuchu, Tokyo, Japan.
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234
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Candelario-Jalil E, Akundi RS, Bhatia HS, Lieb K, Appel K, Muñoz E, Hüll M, Fiebich BL. Ascorbic acid enhances the inhibitory effect of aspirin on neuronal cyclooxygenase-2-mediated prostaglandin E2 production. J Neuroimmunol 2006; 174:39-51. [PMID: 16529823 DOI: 10.1016/j.jneuroim.2006.01.003] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2005] [Revised: 12/22/2005] [Accepted: 01/09/2006] [Indexed: 12/31/2022]
Abstract
Inhibition of neuronal cyclooxygenase-2 (COX-2) and hence prostaglandin E2 (PGE2) synthesis by non-steroidal anti-inflammatory drugs has been suggested to protect neuronal cells in a variety of pathophysiological situations including Alzheimer's disease and ischemic stroke. Ascorbic acid (vitamin C) has also been shown to protect cerebral tissue in a variety of experimental conditions, which has been attributed to its antioxidant capacity. In the present study, we show that ascorbic acid dose-dependently inhibited interleukin-1beta (IL-1beta)-mediated PGE2 synthesis in the human neuronal cell line, SK-N-SH. Furthermore, in combination with aspirin, ascorbic acid augmented the inhibitory effect of aspirin on PGE2 synthesis. However, ascorbic acid had no synergistic effect along with other COX inhibitors (SC-58125 and indomethacin). The inhibition of IL-1beta-mediated PGE2 synthesis by ascorbic acid was not due to the inhibition of the expression of COX-2 or microsomal prostaglandin E synthase (mPGES-1). Rather, ascorbic acid dose-dependently (0.1-100 microM) produced a significant reduction in IL-1beta-mediated production of 8-iso-prostaglandin F2alpha (8-iso-PGF2alpha), a reliable indicator of free radical formation, suggesting that the effects of ascorbic acid on COX-2-mediated PGE2 biosynthesis may be the result of the maintenance of the neuronal redox status since COX activity is known to be enhanced by oxidative stress. Our results provide in vitro evidence that the neuroprotective effects of ascorbic acid may depend, at least in part, on its ability to reduce neuronal COX-2 activity and PGE2 synthesis, owing to its antioxidant properties. Further, these experiments suggest that a combination of aspirin with ascorbic acid constitutes a novel approach to render COX-2 more sensitive to inhibition by aspirin, allowing an anti-inflammatory therapy with lower doses of aspirin, thereby avoiding the side effects of the usually high dose aspirin treatment.
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Affiliation(s)
- Eduardo Candelario-Jalil
- Neurochemistry Research Group, Department of Psychiatry, University of Freiburg Medical School, Hauptstrasse 5, D-79104 Freiburg, Germany
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235
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Takadera T, Ohyashiki T. Prevention of rat cortical neurons from prostaglandin E2-induced apoptosis by glycogen synthase kinase-3 inhibitors. Neurosci Lett 2006; 400:105-9. [PMID: 16504398 DOI: 10.1016/j.neulet.2006.02.014] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2005] [Revised: 01/16/2006] [Accepted: 02/07/2006] [Indexed: 10/25/2022]
Abstract
Cyclooxygenase-2 (COX-2) induction and prostaglandin E(2) (PGE(2)) elevation have been reported to occur after cerebral ischemic insult. PGE(2) induces apoptosis through the PGE(2) EP2 receptor by a cAMP-dependent pathway. Glycogen synthase kinase-3 (GSK-3) affects many fundamental cellular functions. We examined whether GSK-3 is involved in PGE(2)-induced cell death by using GSK-3 inhibitors in rat cultured cortical neurons. Cells treated with 12.5 microM PGE(2) for 2 days shrank. The injured cells underwent chromatin condensation and nuclear fragmentation detected by staining with Hoechst33258, indicating apoptotic cell death. We assayed the effects of selective GSK-3 inhibitors SB216763 and alsteropaullone on PGE(2)-induced apoptosis. These inhibitors completely protected the cells from apoptosis induced by PGE(2). Moreover, dibutyryl cAMP (a cell permeable cAMP)-induced apoptosis was also prevented by alsteropaullone. In addition, GSK-3 inhibitors inhibited caspase-3 activation accompanied by PGE(2)-induced apoptosis. We showed in this report that PGE(2)-induced apoptosis is prevented by GSK-3 inhibitors, suggesting that PGE(2) induces caspase-dependent apoptosis mediated through GSK-3 activation in rat cultured cortical neurons.
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Affiliation(s)
- Tsuneo Takadera
- Department of Clinical Chemistry, Faculty of Pharmaceutical Sciences, Hokuriku University, Kanazawa, Ishikawa 920-1148, Japan.
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236
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Ge QF, Wei EQ, Zhang WP, Hu X, Huang XJ, Zhang L, Song Y, Ma ZQ, Chen Z, Luo JH. Activation of 5-lipoxygenase after oxygen-glucose deprivation is partly mediated via NMDA receptor in rat cortical neurons. J Neurochem 2006; 97:992-1004. [PMID: 16606359 DOI: 10.1111/j.1471-4159.2006.03828.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
5-Lipoxygenase (5-LOX) is the enzyme metabolizing arachidonic acid to produce pro-inflammatory leukotrienes. We have reported that 5-LOX is translocated to the nuclear envelope after ischemic-like injury in PC12 cells. In the present study, we determined whether 5-LOX is activated (translocation and production of leukotrienes) after oxygen-glucose deprivation (OGD) in primary rat cortical neurons; if so, whether this activation is mediated by NMDA receptor. After OGD, 5-LOX was translocated to the nuclear envelope as detected by immunoblotting, immunostaining and green fluorescent protein-5-LOX transfection. 5-LOX metabolites, cysteinyl-leukotrienes (CysLTs) but not leukotriene B4, in the culture media were increased 0.5-1.5 h after recovery. Similarly, NMDA (100 microm) also induced 5-LOX translocation, and increased the production of CysLTs during 0.5-1 h NMDA exposure. Both OGD and NMDA reduced neuron viability. NMDA receptor antagonist MK-801 inhibited almost all the responses to OGD and NMDA; whereas 5-LOX activating protein inhibitor MK-886 and 5-LOX inhibitor caffeic acid inhibited the reduction of neuron viability and the production of CysLTs, but did not affect 5-LOX translocation. From these results, we conclude that OGD can activate 5-LOX in primary rat cortical neurons, and that this activation may be partly mediated via activating NMDA receptor.
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Affiliation(s)
- Qiu-Fu Ge
- Department of Pharmacology, Zheijang University School of Medicine, Hangzhou, China
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237
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Song Y, Wei EQ, Zhang WP, Ge QF, Liu JR, Wang ML, Huang XJ, Hu X, Chen Z. Minocycline protects PC12 cells against NMDA-induced injury via inhibiting 5-lipoxygenase activation. Brain Res 2006; 1085:57-67. [PMID: 16574083 DOI: 10.1016/j.brainres.2006.02.042] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2005] [Revised: 02/02/2006] [Accepted: 02/07/2006] [Indexed: 11/24/2022]
Abstract
Recently, we have reported that minocycline, a semi-synthetic tetracycline with neuroprotective effects, inhibits the in vitro ischemic-like injury and 5-lipoxygenase (5-LOX) activation in PC12 cells. In the present study, we further determined whether minocycline protects PC12 cells from excitotoxicity via inhibiting 5-LOX activation. We used N-methyl-d-aspartate (NMDA, 200 microM) to induce early (exposure for 6 h) and delayed (exposure for 6 h followed by 24 h recovery) injuries. We found that NMDA receptor antagonist ketamine, 5-LOX inhibitor caffeic acid and minocycline concentration dependently attenuated NMDA-induced early and delayed cell injuries (viability reduction and cell death). However, only ketamine (1 microM) inhibited NMDA-evoked elevation of intracellular calcium. In addition, immunohistochemical analysis showed that NMDA induced 5-LOX translocation to the nuclear membrane after 1- to 6-h exposure which was confirmed by Western blotting, indicating that 5-LOX was activated. Ketamine, caffeic acid and minocycline (each at 1 microM) inhibited 5-LOX translocation after early injury. After delayed injury, PC12 cells were shrunk, and 5-LOX was translocated to the nuclei and nuclear membrane; ketamine, caffeic acid and minocycline inhibited both cell shrinking and 5-LOX translocation. As a control, 12-LOX inhibitor baicalein showed a weak effect on cell viability and death, but no effect on 5-LOX translocation. Therefore, we conclude that the protective effect of minocycline on NMDA-induced injury is partly mediated by inhibiting 5-LOX activation.
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Affiliation(s)
- Ying Song
- Department of Pharmacology, School of Medicine, Zhejiang University, Hangzhou 310031, PR China
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238
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Singhal AB, Lo EH, Dalkara T, Moskowitz MA. Advances in stroke neuroprotection: hyperoxia and beyond. Neuroimaging Clin N Am 2006; 15:697-720, xii-xiii. [PMID: 16360598 DOI: 10.1016/j.nic.2005.08.014] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Refinements in patient selection, improved methods of drug delivery, use of more clinically relevant animal stroke models, and the use of combination therapies that target the entire neurovascular unit make stroke neuroprotection an achievable goal. This article provides an overview of the major mechanisms of neuronal injury and the status of neuroprotective drug trials and reviews emerging strategies for treatment of acute ischemic stroke. Advances in the fields of stem cell transplantation, stroke recovery, molecular neuroimaging, genomics, and proteomics will provide new therapeutic avenues in the near future. These and other developments over the past decade raise expectations that successful stroke neuroprotection is imminent.
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239
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Carlson NG, Hill KE, Tsunoda I, Fujinami RS, Rose JW. The pathologic role for COX-2 in apoptotic oligodendrocytes in virus induced demyelinating disease: implications for multiple sclerosis. J Neuroimmunol 2006; 174:21-31. [PMID: 16516308 DOI: 10.1016/j.jneuroim.2006.01.008] [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] [Received: 08/16/2005] [Revised: 12/08/2005] [Accepted: 01/04/2006] [Indexed: 02/05/2023]
Abstract
The objective of this study was examine whether the inducible isoform of the enzyme cyclooxygenase (COX-2) was expressed in dying oligodendrocytes in the Theiler's murine encephalomyelitis virus (TMEV) induced demyelinating disease (TMEV-IDD), an experimental animal model for multiple sclerosis (MS). COX-2 is an enzyme that is tightly coupled to neuronal excitotoxic death. Since neuronal expression of COX-2 contributes to the susceptibility of neurons to excitotoxic death, we asked whether COX-2 was expressed in oligodendrocytes in MS plaques and in lesions during TMEV-IDD. COX-2 was expressed in oligodendrocytes in chronic active lesions from two MS patients. Similar pathology was present in TMEV-IDD spinal cord lesions. COX-2 was expressed in oligodendrocytes four weeks after infection with TMEV coincident with the onset of demyelination. A marker for apoptotic death, activated caspase 3, was present in a subset of oligodendrocytes that expressed COX-2. Oligodendrocyte expression of COX-2 in TMEV-IDD and MS lesions is consistent with a pathological role for this enzyme in demyelination. The presence of the cell death marker (activated caspase 3) with COX-2 in oligodendrocytes is direct evidence linking COX-2 with cell death of oligodendrocytes in these demyelinating diseases.
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Affiliation(s)
- Noel G Carlson
- Geriatric Research Education and Clinical Center (GRECC), Salt Lake City, UT 84148, USA.
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240
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Cho S, Park EM, Febbraio M, Anrather J, Park L, Racchumi G, Silverstein RL, Iadecola C. The class B scavenger receptor CD36 mediates free radical production and tissue injury in cerebral ischemia. J Neurosci 2006; 25:2504-12. [PMID: 15758158 PMCID: PMC6725161 DOI: 10.1523/jneurosci.0035-05.2005] [Citation(s) in RCA: 161] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The class B scavenger receptor CD36 is involved in the cytotoxicity associated with inflammation, but its role in the inflammatory reaction that accompanies cerebral ischemia has not been examined. In this study, we investigated whether CD36 contributes to the brain damage produced by cerebral ischemia. The middle cerebral artery was transiently occluded in wild-type mice and in mice deficient in CD36. In wild-type mice, CD36 protein expression was increased in the ischemic brain, such that it was located predominantly in cells expressing the microglia/macrophage marker CD11b. The infarct produced by middle cerebral artery occlusion was 49% smaller in CD36-null mice than in wild-type controls, an effect associated with improved neurological function. The attenuation in brain injury in CD36 nulls could not be attributed to differences in cerebral blood flow during ischemia-reperfusion. However, the increase in reactive oxygen species (ROS) produced by cerebral ischemia was markedly attenuated in CD36-null mice in the early stage after reperfusion. The data unveil a previously unrecognized role of CD36 in ischemia-induced ROS production and brain injury. Modulation of CD36 signaling may provide a new strategy for the treatment of ischemic stroke.
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Affiliation(s)
- Sunghee Cho
- Division of Neurobiology, Weill Medical College of Cornell University, New York, New York 10021, USA
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241
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Sang N, Zhang J, Marcheselli V, Bazan NG, Chen C. Postsynaptically synthesized prostaglandin E2 (PGE2) modulates hippocampal synaptic transmission via a presynaptic PGE2 EP2 receptor. J Neurosci 2006; 25:9858-70. [PMID: 16251433 PMCID: PMC6725559 DOI: 10.1523/jneurosci.2392-05.2005] [Citation(s) in RCA: 149] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Increasing evidence suggests that cyclooxygenase-2 (COX-2) is involved in synaptic transmission and plasticity, and prostaglandin E2 (PGE2) is a key molecule in COX-2-meduated synaptic modification. However, the precise mechanisms, in particular, which subtypes of PGE2 receptors (EPs) mediate the PGE2-induced synaptic response, are not clear. Recently, we demonstrated that EPs are expressed heterogeneously in the hippocampus, and EP2/4 are mainly expressed in presynaptic terminals. Here, we report that PGE2 increased synaptic stimulus-evoked amplitudes of EPSPs in hippocampal slices and frequency of miniature EPSCs (mEPSCs) in hippocampal neurons in culture. These actions were mimicked by an EP2 agonist and attenuated by protein kinase A inhibitors. Decrease of EP2 expression through silencing the EP2 gene eliminated PGE2-induced increase of the frequency of mEPSCs. COX-2 and microsomal PGE synthase-1 (mPGES-1) and mPGES-2 are present in postsynaptic dendritic spines, because they are colocalized with PSD-95 (postsynaptic density-95), a postsynaptic marker. In addition, the frequency of mEPSCs was enhanced in neurons pretreated with interleukin-1beta or lipopolysaccharide, which elevated expression of COX-2 and mPGES-1 and produced PGE2, and this enhancement was inhibited by a COX-2 inhibitor that inhibited production of PGE2. Our results suggest that PGE2 synthesized by postsynaptically localized COX-2 functions as a retrograde messenger in hippocampal synaptic signaling via a presynaptic EP2 receptor.
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Affiliation(s)
- Nan Sang
- Neuroscience Center of Excellence, School of Medicine, Louisiana State University Health Sciences Center, New Orleans, Louisiana 70112, USA
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242
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Abstract
The neuropathology of Alzheimer's disease (AD) is characterized by deposits of amyloid beta (Abeta) peptides and neurofibrillary tangles, but also, among other aspects, by signs of a chronic inflammatory process. Epidemiological studies have shown that long-term use of nonsteroidal antiinflammatory drugs (NSAIDs) reduces the risk of developing AD and delays its onset. The classic target of NSAIDs is the prevention of cyclooxygenase (COX) activation. The main mechanism of action of COXs is the synthesis of prostaglandins, some of which have potent inflammatory activity. The discovery of two isoforms of this enzyme, COX-1 and COX-2, and that the latter is inducible by inflammatory cytokines supported the hypothesis that its inhibition would result in a potent antiinflammatory effect and led to the rapid development of selective COX-2 inhibitors, collectively called coxibs. Based on this rationale, some coxibs have been used in clinical trials for AD patients, but all the results obtained so far have been negative. Here, we review our knowledge in terms of COX-2 in the central nervous system, COX-2 and Abeta formation, and finally COX-2 and AD pathogenesis to understand the reasons why these drugs have failed and whether there is any scientific support to keep them as therapeutic tools for this chronic disease.
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Affiliation(s)
- Omidreza Firuzi
- Department of Pharmacology, University of Pennsylvania, School of Medicine. Philadelphia, PA 19014, USA
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243
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Kawano T, Anrather J, Zhou P, Park L, Wang G, Frys KA, Kunz A, Cho S, Orio M, Iadecola C. Prostaglandin E2 EP1 receptors: downstream effectors of COX-2 neurotoxicity. Nat Med 2006; 12:225-9. [PMID: 16432513 DOI: 10.1038/nm1362] [Citation(s) in RCA: 315] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2005] [Accepted: 01/02/2006] [Indexed: 12/18/2022]
Abstract
Cyclooxygenase-2 (COX-2), a rate-limiting enzyme for prostanoid synthesis, has been implicated in the neurotoxicity resulting from hypoxia-ischemia, and its inhibition has therapeutic potential for ischemic stroke. However, COX-2 inhibitors increase the risk of cardiovascular complications. We therefore sought to identify the downstream effectors of COX-2 neurotoxicity, and found that prostaglandin E(2) EP1 receptors are essential for the neurotoxicity mediated by COX-2-derived prostaglandin E(2). EP1 receptors disrupt Ca(2+) homeostasis by impairing Na(+)-Ca(2+) exchange, a key mechanism by which neurons cope with excess Ca(2+) accumulation after an excitotoxic insult. Thus, EP1 receptors contribute to neurotoxicity by augmenting the Ca(2+) dysregulation underlying excitotoxic neuronal death. Pharmacological inhibition or gene inactivation of EP1 receptors ameliorates brain injury induced by excitotoxicity, oxygen glucose deprivation and middle cerebral artery (MCA) occlusion. An EP1 receptor inhibitor reduces brain injury when administered 6 hours after MCA occlusion, suggesting that EP1 receptor inhibition may be a viable therapeutic option in ischemic stroke.
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Affiliation(s)
- Takayuki Kawano
- Department of Neurology and Neuroscience, Weill Medical College of Cornell University, New York, New York 10021, USA
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244
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Reimsnider S, Wood CE. Differential modulation of ovine fetal ACTH secretion by PGHS-1 and PGHS-2. Neuroendocrinology 2006; 83:4-11. [PMID: 16682807 DOI: 10.1159/000093177] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2006] [Accepted: 03/30/2006] [Indexed: 11/19/2022]
Abstract
BACKGROUND/AIMS We have previously demonstrated that prostaglandin generation within the fetal brain augments or partially mediates fetal reflex responsiveness to hypotension. The present study was performed to test the relative roles of prostaglandin endoperoxide synthases-1 and -2 (PGHS-1 and 2, or COX-1 and 2) as potential mediators of this interaction. METHODS Chronically catheterized and instrumented fetal sheep were subjected to transient brachiocephalic occlusion (BCO) after intracerebroventricular injection of resveratrol (PGHS-1 or COX-1 inhibitor), nimesulide (PGHS-2 or COX-2 inhibitor), or vehicle. RESULTS BCO decreased arterial pressure perfusing the fetal brain and stimulated increases in systemic blood pressure and heart rate as well as in circulating concentrations of ACTH. Inhibition of PGHS-1 and PGHS-2 had differential effects on fetal ACTH secretion. Pre-BCO concentrations of plasma ACTH increased in response to nimesulide, while the fetal ACTH response to BCO was delayed by resveratrol. Prior to the BCO, nimesulide also increased fetal blood pressure and decreased fetal heart rate. The injections of resveratrol and nimesulide did not alter placental biosynthesis of prostaglandins and therefore acted within the fetal brain. CONCLUSION We conclude that prostaglandin generated in the fetal brain by the action of PGHS-1 augments fetal ACTH reflex responses to BCO but that, in contrast, the action of PGHS-2 is inhibitory to ACTH secretion.
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Affiliation(s)
- Sharon Reimsnider
- Department of Physiology and Functional Genomics, University of Florida College of Medicine, Gainesville, Fla. 32610-0274, USA
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245
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Abstract
The cerebrovascular endothelium exerts a profound influence on cerebral vessels and cerebral blood flow. This review summarizes current knowledge of various dilator and constrictor mechanisms intrinsic to the cerebrovascular endothelium. The endothelium contributes to the resting tone of cerebral arteries and arterioles by tonically releasing nitric oxide (NO•). Dilations can occur by stimulated release of NO•, endothelium-derived hyperpolarization factor, or prostanoids. During pathological conditions, the dilator influence of the endothelium can turn to that of constriction by a variety of mechanisms, including decreased NO• bioavailability and release of endothelin-1. The endothelium may participate in neurovascular coupling by conducting local dilations to upstream arteries. Further study of the cerebrovascular endothelium is critical for understanding the pathogenesis of a number of pathological conditions, including stroke, traumatic brain injury, and subarachnoid hemorrhage.
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Affiliation(s)
- Jon Andresen
- Department of Anesthesiology, Baylor College of Medicine, One Baylor Plaza, Suite 434D, Houston, Texas 77030, USA.
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246
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Chen C, Bazan NG. Lipid signaling: sleep, synaptic plasticity, and neuroprotection. Prostaglandins Other Lipid Mediat 2005; 77:65-76. [PMID: 16099392 DOI: 10.1016/j.prostaglandins.2005.07.001] [Citation(s) in RCA: 122] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2004] [Accepted: 07/02/2005] [Indexed: 01/25/2023]
Abstract
Increasing evidence indicates that bioactive lipids participate in the regulation of synaptic function and dysfunction. We have demonstrated that signaling mediated by platelet-activating factor (PAF) and cyclooxygenase (COX)-2-synthesized PGE2 is involved in synaptic plasticity, memory, and neuronal protection [Clark GD, Happel LT, Zorumski CF, Bazan NG. Enhancement of hippocampal excitatory synaptic transmission by platelet-activating factor. Neuron 1992; 9:1211; Kato K, Clark GD, Bazan NG, Zorumski CF. Platelet-activating factor as a potential retrograde messenger in CA1 hippocampal long-term potentiation. Nature 1994; 367:175; Izquierdo I, Fin C, Schmitz PK, et al. Memory enhancement by intrahippocampal, intraamygdala or intraentorhinal infusion of platelet-activating factor measured in an inhibitory avoidance. Proc Natl Acad Sci USA 1995; 92:5047; Chen C, Magee CJ, Bazan NG. Cyclooxygenase-2 regulates prostaglandin E2 signaling in hippocampal long-term synaptic plasticity. J Neurophysiol 2002; 87:2851]. Recently, we found that prolonged continuous wakefulness (primarily rapid eye movement (REM)-sleep deprivation, SD) causes impairments in hippocampal long-term synaptic plasticity and hippocampus-dependent memory formation [McDermott CM, LaHoste GJ, Chen C, Musto A, Bazan NG, Magee JC. Sleep deprivation causes behavioral, synaptic, and membrane excitability alterations in hippocampal neurons. J Neurosci 2003; 23:9687]. To explore the mechanisms underlying SD-induced impairments, we have studied several bioactive lipids in the hippocampus following SD. It appears that SD causes increases in prostaglandin D2 (PGD2) and 2-arachidonylglycerol (2-AG), and a decrease in PGE2, suggesting that these lipid messengers participate in memory consolidation during REM sleep. We have also explored the formation of endogenous neuroprotective lipids. Toward this aim, we have used ischemia-reperfusion damage and LC-PDA-ESI-MS-MS-based lipidomic analysis and identified docosanoids derived from synaptic phospholipid-enriched docosahexaenoic acid. Some of the docosanoids exert potent neuroprotective bioactivity [Marcheselli VL, Hong S, Lukiw WJ, et al. Novel docosanoids inhibit brain ischemia-reperfusion-mediated leukocyte infiltration and pro-inflammatory gene expression. J Biol Chem 2003; 278:43807; Mukherjee PK, Marcheselli VL, Serhan CN, Bazan, NG. Neuroprotectin D1: A docosahexaenoic acid-derived docosatriene protects human retinal pigment epithelial cells from oxidative stress. Proc Nat Acad Sci USA 2004; 101:8491). Taken together, these observations that signaling lipids participate in synaptic plasticity, cognition, and survival indicate that lipid signaling is closely associated with several functions (e.g; learning and memory, sleep, and experimental stroke) and pathologic events. Alterations in endogenous signaling lipids or their receptors resulting from drug abuse lead to changes in synaptic circuitry and induce profound effects on these important functions. In the present article, we will briefly review bioactive lipids involved in sleep, synaptic transmission and plasticity, and neuroprotection, focusing mainly on our experimental studies and how these signaling molecules are related to functions and implicated in some neurologic disorders.
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Affiliation(s)
- Chu Chen
- Neuroscience Center of Excellence and Department of Ophthamology, Louisiana State University Health Sciences Center, School of Medicine in New Orleans, 2020 Gravier Street, Suite D, New Orleans, LA 70112, USA
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Takadera T, Ohyashiki T. Prostaglandin E2 deteriorates N-methyl-D-aspartate receptor-mediated cytotoxicity possibly by activating EP2 receptors in cultured cortical neurons. Life Sci 2005; 78:1878-83. [PMID: 16309709 DOI: 10.1016/j.lfs.2005.08.026] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2005] [Accepted: 08/27/2005] [Indexed: 10/25/2022]
Abstract
The activation of glutamate receptors, particularly N-methyl-D-aspartate (NMDA) receptors, initiates ischemic cascade in the early stages of cerebral ischemia. Postischemia, cerebral ischemia is also associated with an inflammatory reaction that contributes to tissue damage. The up-regulation of neuronal cyclooxygenase-2 (COX-2) and elevation of prostaglandin E2 (PGE2) have been reported to occur after cerebral ischemic insult. We therefore studied whether the COX-2 reaction product PGE2 affects glutamate receptor-mediated cell death in cultured rat cortical cells. PGE2 was found to augment NMDA-mediated cell death. The transcription of EP1, EP2, EP3 and EP4 PGE2 receptor genes was investigated using reverse transcriptase-polymerase chain reaction (RT-PCR). EP1, EP2 and EP3 receptor genes were found in cortical cells. Butaprost (an EP2 agonist) markedly enhanced NMDA-mediated cell death, whereas 17-phenyl trinor-PGE2 (an EP1 agonist) and sulprostone (an EP3 agonist) had little effect. Both PGE2 and butaprost elevated cAMP intracellular levels in the cortical cells; moreover, forskolin, an activator of adenylate cyclase, enhanced NMDA-mediated cell death. These results suggest that PGE2, acting via EP2 receptors, aggravates excitotoxic neurodegeneration by a cAMP-dependent mechanism.
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Affiliation(s)
- Tsuneo Takadera
- Department of Clinical Chemistry, Faculty of Pharmaceutical Sciences, Hokuriku University, Kanazawa, 920-1148 Japan.
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248
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Abstract
Three routes have been identified triggering neuronal death under physiological and pathological conditions. Excess activation of ionotropic glutamate receptors cause influx and accumulation of Ca2+ and Na+ that result in rapid swelling and subsequent neuronal death within a few hours. The second route is caused by oxidative stress due to accumulation of reactive oxygen and nitrogen species. Apoptosis or programmed cell death that often occurs during developmental process has been coined as additional route to pathological neuronal death in the mature nervous system. Evidence is being accumulated that excitotoxicity, oxidative stress, and apoptosis propagate through distinctive and mutually exclusive signal transduction pathway and contribute to neuronal loss following hypoxic-ischemic brain injury. Thus, the therapeutic intervention of hypoxic-ischemic neuronal injury should be aimed to prevent excitotoxicity, oxidative stress, and apoptosis in a concerted way.
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Affiliation(s)
- Seok Joon Won
- Center for the Interventional Therapy of Stroke and Alzheimers Disease, Department of Pharmacology, Ajou University School of Medicine, San 5, Wonchondong, Paldalgu, Suwon, Kyungkido 442-749, South Korea
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Herrmann O, Baumann B, de Lorenzi R, Muhammad S, Zhang W, Kleesiek J, Malfertheiner M, Köhrmann M, Potrovita I, Maegele I, Beyer C, Burke JR, Hasan MT, Bujard H, Wirth T, Pasparakis M, Schwaninger M. IKK mediates ischemia-induced neuronal death. Nat Med 2005; 11:1322-9. [PMID: 16286924 DOI: 10.1038/nm1323] [Citation(s) in RCA: 216] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2005] [Accepted: 10/05/2005] [Indexed: 12/23/2022]
Abstract
The IkappaB kinase complex IKK is a central component of the signaling cascade that controls NF-kappaB-dependent gene transcription. So far, its function in the brain is largely unknown. Here, we show that IKK is activated in a mouse model of stroke. To investigate the function of IKK in brain ischemia we generated mice that contain a targeted deletion of Ikbkb (which encodes IKK2) in mouse neurons and mice that express a dominant inhibitor of IKK in neurons. In both lines, inhibition of IKK activity markedly reduced infarct size. In contrast, constitutive activation of IKK2 enlarged the infarct size. A selective small-molecule inhibitor of IKK mimicked the effect of genetic IKK inhibition in neurons, reducing the infarct volume and cell death in a therapeutic time window of 4.5 h. These data indicate a key function of IKK in ischemic brain damage and suggest a potential role for IKK inhibitors in stroke therapy.
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Affiliation(s)
- Oliver Herrmann
- Department of Neurology, University of Heidelberg, Im Neuenheimer Feld 400, 69120 Heidelberg, Germany
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Ahmad AS, Saleem S, Ahmad M, Doré S. Prostaglandin EP1 receptor contributes to excitotoxicity and focal ischemic brain damage. Toxicol Sci 2005; 89:265-70. [PMID: 16237196 DOI: 10.1093/toxsci/kfj022] [Citation(s) in RCA: 101] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The clinical side effects associated with the inhibition of cyclooxygenase enzymes under pathologic conditions have recently raised concerns. A better understanding of neuroinflammatory mechanisms and neuronal survival requires knowledge of cyclooxygenase downstream pathways, especially PGE2 and its G-protein-coupled receptors. In this study, we postulate that EP1 receptor is one of the mechanisms that propagate neurotoxicity and could be a therapeutic target in brain injury. This hypothesis was tested by pretreating C57BL/6 wildtype mice with the EP1 receptor selective agonist ONO-DI-004 and the selective antagonist ONO-8713, followed by striatal unilateral NMDA injection. Results revealed that ONO-DI-004 increased NMDA-induced lesion volume up to 128.7 +/- 12.0%, while ONO-8713 significantly decreased lesion volume to 71.3 +/- 10.9%, as compared to the NMDA-control group. Neurotoxic EP1 receptor properties were also studied using C57BL/6 EP1 receptor knockout (EP1-/-) mice, which revealed a significant decrease to 74.5 +/- 8.2%, as compared to wildtype controls. The protective effect of the antagonist ONO-8713 was also tested in the EP1-/- mice, revealing no additional protection in these mice. Together, these results support the selectivity of ONO-8713 toward EP1 receptor and suggest the neurotoxic role of EP1 receptor. Furthermore, the EP1 receptor role in ischemic brain damage was investigated using a model of middle cerebral artery occlusion (MCAO) and reperfusion. The infarct volume was significantly reduced to 56.9 +/- 11.5% in EP1-/- mice, as compared to wildtype controls. This is the first study that demonstrates that EP1 receptor aggravates neurotoxicity and that modulation of this receptor can determine the outcomes in both excitotoxic and focal ischemic neuronal damage.
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Affiliation(s)
- Abdullah Shafique Ahmad
- Department of Anesthesiology & Critical Care Medicine, Johns Hopkins University, Baltimore, Maryland 21205, USA
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