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Sil S, Ghosh T. Role of cox-2 mediated neuroinflammation on the neurodegeneration and cognitive impairments in colchicine induced rat model of Alzheimer's Disease. J Neuroimmunol 2015; 291:115-24. [PMID: 26857505 DOI: 10.1016/j.jneuroim.2015.12.003] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Revised: 11/30/2015] [Accepted: 12/09/2015] [Indexed: 11/15/2022]
Abstract
The neurodegeneration in colchicine induced AD (cAD) rats is linked with neuroinflammation. The inducible cox-2 present in the brain may participate in the neuroinflammatory process related to progressive neurodegeneration in cAD rats. The aim of this study is to investigate the role of cox-2 in the neurodegeneration and cognitive impairments in cAD rats. The parameters of memory (working and reference memory), inflammatory markers [IL-1β, TNF-α, prostaglandin E2 (PGE2), cox-2 level] and histopathology of hippocampus were measured after 21-day of i.c.v. colchicine injection in rats and compared with that of control and sham operated rats. These parameters were also measured in these 3 different groups of rats after p.o. administration of 3 different doses of etoricoxib, a cox 2 inhibitor. The impairments of working and reference memory were associated with neuroinflammation and neurodegeneration in the hippocampus and increased cox-2 and PGE2 levels in hippocampus in cAD. Administration of etoricoxib in cAD rats resulted in recovery of memory impairments, neurodegeneration and neuroinflammation in hippocampus and inhibition of cox-2 and PGE2 levels in hippocampus. It appears from the results that activation of cox-2 in cAD is related to neuroinflammation involved in neurodegeneration. Colchicine induced initial neurodegeneration may trigger cascade of events for a progressive neurodegeneration where cox-2 activation plays a critical role. Moreover, this cox-2 mediated neurodegeneration is related to impairments of memory parameters. Thus, the present study showed that the impairments of memory and neurodegeneration in the hippocampus of cAD in 21-day study are mediated by cox-2 induced neuroinflammation.
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Affiliation(s)
- Susmita Sil
- Neurophysiology laboratory, Department of Physiology, University College of Science and Technology, University of Calcutta, 92, Acharya Prafulla Chandra Road, Kolkata 700 009, West Bengal, India.
| | - Tusharkanti Ghosh
- Neurophysiology laboratory, Department of Physiology, University College of Science and Technology, University of Calcutta, 92, Acharya Prafulla Chandra Road, Kolkata 700 009, West Bengal, India.
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Rizvi SMD, Shaikh S, Waseem SMA, Shakil S, Abuzenadah AM, Biswas D, Tabrez S, Ashraf GM, Kamal MA. Role of anti-diabetic drugs as therapeutic agents in Alzheimer's disease. EXCLI JOURNAL 2015; 14:684-96. [PMID: 27152105 PMCID: PMC4849108 DOI: 10.17179/excli2015-252] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Accepted: 05/05/2015] [Indexed: 12/16/2022]
Abstract
Recent data have suggested a strong possible link between Type 2 Diabetes Mellitus and Alzheimer's disease (AD), although exact mechanisms linking the two are still a matter of research and debate. Interestingly, both are diseases with high incidence and prevalence in later years of life. The link appears so strong that some scientists use Alzheimer's and Type 3 Diabetes interchangeably. In depth study of recent data suggests that the anti diabetic drugs not only have possible role in treatment of Alzheimer's but may also arrest the declining cognitive functions associated with it. The present review gives an insight into the possible links, existing therapeutics and clinical trials of anti diabetic drugs in patients suffering from AD primarily or as co-morbidity. It may be concluded that the possible beneficial effects and usefulness of the current anti diabetic drugs in AD cannot be neglected and further research is required to achieve positive results. Currently, several drug trials are in progress to give conclusive evidence based data.
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Affiliation(s)
| | | | - Shah Mohammad Abbas Waseem
- Department of Physiology, Integral Institute of Medical Sciences & Research, Integral University, Lucknow, India
| | - Shazi Shakil
- Center of Innovation in Personalized Medicine, Faculty of Applied Medical Sciences,King Abdulaziz University, Jeddah, Saudi Arabia
| | - Adel M. Abuzenadah
- Center of Innovation in Personalized Medicine, Faculty of Applied Medical Sciences,King Abdulaziz University, Jeddah, Saudi Arabia
| | | | - Shams Tabrez
- King Fahd Medical Research Center, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Ghulam Md. Ashraf
- King Fahd Medical Research Center, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Mohammad Amjad Kamal
- King Fahd Medical Research Center, King Abdulaziz University, Jeddah, Saudi Arabia
- Enzymoic, 7 Peterlee Pl, Hebersham, NSW 2770, Australia
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Nazem A, Sankowski R, Bacher M, Al-Abed Y. Rodent models of neuroinflammation for Alzheimer's disease. J Neuroinflammation 2015; 12:74. [PMID: 25890375 PMCID: PMC4404276 DOI: 10.1186/s12974-015-0291-y] [Citation(s) in RCA: 155] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2015] [Accepted: 03/27/2015] [Indexed: 12/24/2022] Open
Abstract
Alzheimer's disease remains incurable, and the failures of current disease-modifying strategies for Alzheimer's disease could be attributed to a lack of in vivo models that recapitulate the underlying etiology of late-onset Alzheimer's disease. The etiology of late-onset Alzheimer's disease is not based on mutations related to amyloid-β (Aβ) or tau production which are currently the basis of in vivo models of Alzheimer's disease. It has recently been suggested that mechanisms like chronic neuroinflammation may occur prior to amyloid-β and tau pathologies in late-onset Alzheimer's disease. The aim of this study is to analyze the characteristics of rodent models of neuroinflammation in late-onset Alzheimer's disease. Our search criteria were based on characteristics of an idealistic disease model that should recapitulate causes, symptoms, and lesions in a chronological order similar to the actual disease. Therefore, a model based on the inflammation hypothesis of late-onset Alzheimer's disease should include the following features: (i) primary chronic neuroinflammation, (ii) manifestations of memory and cognitive impairment, and (iii) late development of tau and Aβ pathologies. The following models fit the pre-defined criteria: lipopolysaccharide- and PolyI:C-induced models of immune challenge; streptozotocin-, okadaic acid-, and colchicine neurotoxin-induced neuroinflammation models, as well as interleukin-1β, anti-nerve growth factor and p25 transgenic models. Among these models, streptozotocin, PolyI:C-induced, and p25 neuroinflammation models are compatible with the inflammation hypothesis of Alzheimer's disease.
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Affiliation(s)
- Amir Nazem
- Elmezzi Graduate School of Molecular Medicine, The Feinstein Institute for Medical Research, 350 Community drive, Manhasset, NY, 11030, USA.
| | - Roman Sankowski
- Elmezzi Graduate School of Molecular Medicine, The Feinstein Institute for Medical Research, 350 Community drive, Manhasset, NY, 11030, USA.
| | - Michael Bacher
- Institute of Immunology, Philipps University Marburg, Hans-Meerwein-Str., 35043, Marburg, Germany.
| | - Yousef Al-Abed
- Center for Molecular Innovation, The Feinstein Institute for Medical Research, 350 Community drive, Manhasset, NY, 11030, USA.
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Trandafir CC, Pouliot WA, Dudek FE, Ekstrand JJ. Co-administration of subtherapeutic diazepam enhances neuroprotective effect of COX-2 inhibitor, NS-398, after lithium pilocarpine-induced status epilepticus. Neuroscience 2014; 284:601-610. [PMID: 25453777 DOI: 10.1016/j.neuroscience.2014.10.021] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Revised: 10/09/2014] [Accepted: 10/10/2014] [Indexed: 12/19/2022]
Abstract
RATIONALE Seizures during status epilepticus (SE) cause neuronal death and induce cyclooxygenase-2 (COX-2). Pilocarpine-induced SE was used to determine if COX-2 inhibition with NS-398, when administered alone or with diazepam, decreases the duration and/or intensity of SE and/or reduces neuronal injury in the rat hippocampus. METHODS Electroencephalogram (EEG) electrodes were implanted in male Sprague-Dawley rats. SE was induced with lithium-pilocarpine, and continuous EEG and video monitoring were performed for 24 h. Rats were divided into four groups (n=8-14 rats/group) and received NS-398, diazepam, NS-398 and diazepam, or vehicle 30 min after the first motor seizure. Six hours later, NS-398 injection was repeated in the NS-398 and in the NS-398+diazepam groups. The duration of SE (continuous spiking) and the EEG power in the γ-band were analyzed. FluoroJade B staining in the dorsal hippocampus at 24h after SE was analyzed semi-quantitatively in the CA1, CA3 and hilus. RESULTS The duration and intensity of electrographic SE was not significantly different across the four groups. In rats treated with NS-398 alone, compared to vehicle-treated rats, neuronal damage was significantly lower compared to vehicle-treated rats in the CA3 (27%) and hilus (27%), but neuroprotection was not detected in the CA1. When NS-398 was administered with diazepam, decreased neuronal damage was further obtained in all areas investigated (CA1: 61%, CA3: 63%, hilus: 60%). CONCLUSIONS NS-398, when administered 30 min after the onset of SE with a repeat dose at 6h, decreased neuronal damage in the hippocampus. Administration of diazepam with NS-398 potentiates the neuroprotective effect of the COX-2 inhibitor. These neuroprotective effects occurred with no detectable effect on electrographic SE.
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Affiliation(s)
- C C Trandafir
- Department of Neurosurgery, University of Utah School of Medicine, Salt Lake City, UT 84108, United States
| | - W A Pouliot
- Department of Neurosurgery, University of Utah School of Medicine, Salt Lake City, UT 84108, United States
| | - F E Dudek
- Department of Neurosurgery, University of Utah School of Medicine, Salt Lake City, UT 84108, United States
| | - J J Ekstrand
- Department of Pediatrics, University of Utah School of Medicine, Salt Lake City, UT 84108, United States.
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Adler BL, Yarchoan M, Hwang HM, Louneva N, Blair JA, Palm R, Smith MA, Lee HG, Arnold SE, Casadesus G. Neuroprotective effects of the amylin analogue pramlintide on Alzheimer's disease pathogenesis and cognition. Neurobiol Aging 2013; 35:793-801. [PMID: 24239383 DOI: 10.1016/j.neurobiolaging.2013.10.076] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2013] [Revised: 10/05/2013] [Accepted: 10/06/2013] [Indexed: 12/24/2022]
Abstract
Amylin is a metabolic peptide hormone that is co-secreted with insulin from beta cells in the pancreas and activates many of the downstream targets of insulin. To investigate the relationship between this hormone and Alzheimer's disease (AD), we measured plasma human amylin levels in 206 subjects with AD, 64 subjects with mild cognitive impairment, and 111 subjects with no cognitive impairment and found significantly lower amylin levels among subjects with AD and mild cognitive impairment compared with the cognitively intact subjects. To investigate mechanisms underlying amylin's effects in the brain, we administered chronic infusions of the amylin analog pramlintide in the senescence-accelerated prone mouse, a mouse model of sporadic AD. Pramlintide administration improved performance in the novel object recognition task, a validated test of memory and cognition. The pramlintide-treated mice had increased expression of the synaptic marker synapsin I and the kinase cyclin-dependent kinase-5 in the hippocampus, as well as decreased oxidative stress and inflammatory markers in the hippocampus. A dose-dependent increase in cyclin-dependent kinase-5 and activation of extracellular-signal-regulated-kinases 1/2 by pramlintide treatment in vitro was also present indicating functionality of the amylin receptor in neurons. Together these results suggest that amylin analogs have neuroprotective properties and might be of therapeutic benefit in AD.
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Affiliation(s)
- Brittany L Adler
- Department of Neurosciences, Case Western Reserve University, Cleveland OH USA
| | - Mark Yarchoan
- Department of Pathology and Laboratory Medicine, Center for Neurodegenerative Disease Research, Institute on Aging, University of Pennsylvania School of Medicine, Philadelphia, PA, USA
| | - Hae Min Hwang
- Department of Neurosciences, Case Western Reserve University, Cleveland OH USA
| | - Natalia Louneva
- Department of Pathology and Laboratory Medicine, Center for Neurodegenerative Disease Research, Institute on Aging, University of Pennsylvania School of Medicine, Philadelphia, PA, USA
| | - Jeffrey A Blair
- Department of Neurosciences, Case Western Reserve University, Cleveland OH USA
| | - Russell Palm
- Department of Neurosciences, Case Western Reserve University, Cleveland OH USA
| | - Mark A Smith
- Department of Pathology, Case Western Reserve University, Cleveland OH USA
| | - Hyoung-Gon Lee
- Department of Pathology, Case Western Reserve University, Cleveland OH USA
| | - Steven E Arnold
- Department of Pathology and Laboratory Medicine, Center for Neurodegenerative Disease Research, Institute on Aging, University of Pennsylvania School of Medicine, Philadelphia, PA, USA.
| | - Gemma Casadesus
- Department of Neurosciences, Case Western Reserve University, Cleveland OH USA.
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Ward NL, Lamanna JC. The neurovascular unit and its growth factors: coordinated response in the vascular and nervous systems. Neurol Res 2013; 26:870-83. [PMID: 15727271 DOI: 10.1179/016164104x3798] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The nervous and vascular systems contain many common organizational features and develop similarly in terms of anatomical patterning. During embryogenesis and in regions of the brain undergoing postnatal neurogenesis, neural stem cells and endothelial cells are found in close proximity, or within a so-called vascular niche. The similarities in patterning and proximity may reflect coordinated development based on responsiveness to similar growth factors such as vascular endothelial growth factor, semaphorin, and ephrins/Ephs: molecules involved in the development and maintenance of both the nervous and vascular systems. Despite the blatant similarities between the vascular and nervous systems, little is still known about the co-dependence and/or interactions between the two systems during development and following alterations in metabolic demand as seen during aging, exercise, and disease processes. The interactions between the two systems involving common growth factors suggest these two systems have evolved in an interconnected way.
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Affiliation(s)
- Nicole L Ward
- Department of Anatomy, School of Medicine, Case Western Reserve University, Cleveland, OH 44106, USA.
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Li W, Wu S, Ahmad M, Jiang J, Liu H, Nagayama T, Rose ME, Tyurin VA, Tyurina YY, Borisenko GG, Belikova N, Chen J, Kagan VE, Graham SH. The cyclooxygenase site, but not the peroxidase site of cyclooxygenase-2 is required for neurotoxicity in hypoxic and ischemic injury. J Neurochem 2010; 113:965-77. [PMID: 20236388 DOI: 10.1111/j.1471-4159.2010.06674.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Cyclooxygenase-2 (COX-2) activity has been implicated in the pathogenesis of ischemic injury, but the exact mechanisms responsible for its toxicity remain unclear. Infection of primary neurons with an adenovirus expressing wild type (WT) COX-2 increased the susceptibility of neurons to hypoxia. Infection with an adenoviral vector expressing COX-2 with a mutation at the cyclooxygenase site did not increase susceptibility to hypoxia, whereas over-expression of COX-2 with a mutation in the peroxidase site produced similar susceptibility to hypoxia as WT COX-2. Primary neuronal cultures obtained from transgenic mice bearing a mutation in the COX-2 cylooxygenase site were protected from hypoxia. Mice with a mutation in the cyclooxygenase site had smaller infarctions 24 h after 70 min of middle cerebral artery occlusion than WT control mice. COX-2 activity had no effect on the formation of protein carbonyls. Ascorbate radicals were detected by electron paramagnetic resonance as a product of recombinant COX-2 activity and were blocked by COX-2 inhibitors. Similarly, formation of ascorbate radicals was inhibited in the presence of COX-2 inhibitors and in homogenates obtained from COX-2 null mice. Taken together, these results indicate that the cyclooxygenase activity of COX-2 is necessary to exacerbate neuronal hypoxia/ischemia injury rather than the peroxidase activity of the enzyme.
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Affiliation(s)
- Wenjin Li
- Geriatric Research Educational and Clinical Center, VA Pittsburgh Healthcare System, University of Pittsburgh, Pittsburgh, Pennsylvania 15205, USA
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9
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Neuroprotective effect of carvedilol, an adrenergic antagonist against colchicine induced cognitive impairment and oxidative damage in rat. Pharmacol Biochem Behav 2009; 92:25-31. [DOI: 10.1016/j.pbb.2008.10.005] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2008] [Revised: 09/12/2008] [Accepted: 10/13/2008] [Indexed: 11/21/2022]
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10
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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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Kumar A, Seghal N, Padi SV, Naidu PS. Differential effects of cyclooxygenase inhibitors on intracerebroventricular colchicine-induced dysfunction and oxidative stress in rats. Eur J Pharmacol 2006; 551:58-66. [PMID: 17027965 DOI: 10.1016/j.ejphar.2006.08.076] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2006] [Revised: 08/16/2006] [Accepted: 08/21/2006] [Indexed: 11/20/2022]
Abstract
Alzheimer's disease is a progressive neurological and psychiatric disorder. Oxidative stress and neuroinflammation have been implicated in pathophysiology of Alzheimer's disease. Inflammatory cells, such as astrocytes and microglia, are activated in areas of the brain affected by amyloid plaques and inflammatory mediators including cytokines, chemokines, prostaglandins, oxygen free radicals and reactive nitrogen species may have a crucial role in Alzheimer's disease pathogenesis. Central administration of colchicine, a microtubule-disrupting agent, causes loss of cholinergic neurons and cognitive dysfunction that is associated with excessive free radical generation. The present study was aimed to evaluate the effects of cyclooxygenase inhibitors against colchicine-induced cognitive dysfunction and oxidative stress in rats. Following intracerebroventricular (i.c.v.) administration of colchicine (15 microg/5 microl), rats exhibited poor retention of memory in Morris water maze and elevated plus maze task paradigms and oxidative stress in rats. Chronic treatment with naproxen (per se; 20 and 40 mg/kg, p.o.) or valdecoxib (per se; 5 and 10 mg/kg, p.o.) daily respectively for a period of 25 days beginning 4 days prior to colchicine injection significantly improved colchicine-induced cognitive impairment. Intracerebroventricular colchicine injection resulted in free radical generation characterized by alterations in oxidative stress markers with a significant increase in malondialdehyde and nitrite levels and depletion of reduced glutathione levels in the brains of rats. It also caused a decrease in acetylcholinesterase activity. Besides, improving cognitive dysfunction, chronic administration of cyclooxygenase inhibitors (naproxen and valdecoxib) significantly reduced elevated malondialdehyde, nitrite levels and restored reduced glutathione levels and acetylcholinesterase activity. The results of the present study indicated that naproxen (per se; 20 and 40 mg/kg, p.o.) or valdecoxib (per se; 5 and 10 mg/kg, p.o.) treatment has a neuroprotective role against colchicine-induced cognitive impairment and associated oxidative stress. The present findings further support the potential use of cyclooxygenase inhibitors in treatment of neurodegenerative diseases such as Alzheimer's disease.
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Affiliation(s)
- Anil Kumar
- Pharmacology Division, University Institute of Pharmaceutical Sciences, Panjab University, Chandigarh-160014, India.
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Kumar A, Naidu PS, Seghal N, Padi SSV. Neuroprotective Effects of Resveratrol against Intracerebroventricular Colchicine-Induced Cognitive Impairment and Oxidative Stress in Rats. Pharmacology 2006; 79:17-26. [PMID: 17135773 DOI: 10.1159/000097511] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2006] [Accepted: 09/13/2006] [Indexed: 12/17/2022]
Abstract
Alzheimer's disease is a complex and multifactorial neurodegenerative disease. Central administration of colchicine, a microtubule-disrupting agent, causes loss of cholinergic neurons and cognitive dysfunction that is associated with excessive free radical generation. The present study was aimed at evaluating the effects of trans-resveratrol in the prevention of colchicine-induced cognitive impairment and oxidative stress in rats. Intracerebroventricular administration of colchicine (15 microg/5 microl) induced impaired cognitive functions in both the Morris water maze task and the elevated plus-maze task. Chronic treatment with resveratrol (10 and 20 mg/kg, p.o.) for a period of 25 days, beginning 4 days prior to colchicine injection, significantly improved the colchicine-induced cognitive impairment. Intracerebroventricular colchicine injection resulted in free radical generation characterized by alterations in oxidative stress markers with a significant increase in malondialdehyde (MDA) and nitrite levels and depletion of reduced glutathione (GSH) activity in the rat brains. It also showed a significant decrease in acetylcholinesterase activity. Besides improving cognitive dysfunction, chronic administration of resveratrol significantly reduced the elevated MDA and nitrite levels and restored the depleted GSH and acetylcholinesterase activity. Results of the present study indicated that trans-resveratrol has a neuroprotective role against colchicine-induced cognitive impairment and associated oxidative stress.
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Affiliation(s)
- A Kumar
- Pharmacology Division, University Institute of Pharmaceutical Sciences, Panjab University, Chandigarh, India.
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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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Abstract
Several epidemiological studies have indicated that the long-term use of NSAIDs, most of which are cyclo-oxygenase (COX) inhibitors, may reduce the risk of Alzheimer's disease. For this reason, anti-inflammatory COX-inhibiting NSAIDs have received increased attention in experimental and therapeutic trials for Alzheimer's disease. However, several recent efforts attempting to demonstrate a therapeutic effect of NSAIDs in Alzheimer's disease have largely failed. Clinicians and scientists currently believe that this lack of success may be attributable to two key problems: (i) clinical trials of NSAIDs have been conducted in patients with late-stage Alzheimer's disease, wherein advanced neurodegeneration may be refractory to anti-inflammatory drug treatment; and (ii) it is not known which of the large family of NSAIDs (i.e. COX-1, COX-2 or mixed inhibitors) is most efficacious in preventing Alzheimer's disease. The wide list of putative functions for COX in the brain, and the significant functional heterogeneity of NSAIDs, which appear to influence the beta-amyloid (Abeta) neuropathology associated with Alzheimer's disease via both COX-dependent and COX-independent pathways, complicate the interpretation of the mechanisms through which COX-inhibiting NSAIDs may beneficially influence Alzheimer's disease. As discussed in this review, for patients at high risk of developing Alzheimer's disease (e.g. those with mild cognitive impairment), preventative treatment with COX-inhibiting NSAIDs may ultimately represent a viable strategy in the management of clinical Alzheimer's disease. However, the recent evidence showing an increased risk of major cardiovascular events among patients treated with certain COX-1 and COX-2 inhibitors leaves many questions unanswered. We suggest that further investigation into the physiological role(s) of COXs in normal health and in disease conditions, and the identification of safer and better tolerated COX inhibitors, will provide renewed impetus to the application of anti-inflammatory strategies for the prevention and treatment of Alzheimer's disease.
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Affiliation(s)
- Lap Ho
- Department of Psychiatry, The Mount Sinai School of Medicine, Neuroinflammation Research Laboratories, New York, New York 10029, USA
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Müller GJ, Geist MA, Veng LM, Willesen MG, Johansen FF, Leist M, Vaudano E. A role for mixed lineage kinases in granule cell apoptosis induced by cytoskeletal disruption. J Neurochem 2006; 96:1242-52. [PMID: 16478524 DOI: 10.1111/j.1471-4159.2005.03590.x] [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] [Indexed: 11/29/2022]
Abstract
Microtubule disruption by colchicine induces apoptosis in selected neuronal populations. However, little is known about the upstream death signalling events mediating the neurotoxicity. We investigated first whether colchicine-induced granule cell apoptosis activates the c-Jun N-terminal kinase (JNK) pathway. Cultured murine cerebellar granule cells were exposed to 1 microm colchicine for 24 h. Activation of the JNK pathway was detected by western blotting as well as immunocytochemistry using antibodies against phospho-c-Jun (p-c-Jun). Next, adult male rats were injected intracerebroventricularly with colchicine (10 microg), and JNK pathway activation in dentate granule cells (DGCs) was detected by antibodies against p-c-Jun. The second part of the study tested the involvement of mixed lineage kinases (MLK) as upstream activators of the JNK pathway in colchicine toxicity, using CEP-1347, a potent MLK inhibitor. In vitro, significant inhibition of the JNK pathway, activated by colchicine, was achieved by 100-300 nm CEP-1347, which blocked both activation of cell death proteases and apoptosis. Moreover, CEP-1347 markedly delayed neurite fragmentation and cell degeneration. In vivo, CEP-1347 (1 mg/kg) significantly prevented p-c-jun increase following injection of colchicine, and enhanced survival of DGCs. We conclude that colchicine-induced neuronal apoptosis involves the JNK/MLK pathway, and that protection of granule cells can be achieved by MLK inhibition.
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Li MH, Jang JH, Surh YJ. Nitric oxide induces apoptosis via AP-1-driven upregulation of COX-2 in rat pheochromocytoma cells. Free Radic Biol Med 2005; 39:890-9. [PMID: 16140209 DOI: 10.1016/j.freeradbiomed.2005.05.015] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2005] [Revised: 05/05/2005] [Accepted: 05/05/2005] [Indexed: 10/25/2022]
Abstract
Cyclooxygenase-2 (COX-2), the rate-limiting enzyme in prostaglandin synthesis, is induced in many cells by numerous inflammatory mediators, including nitric oxide (NO). Upregulation of COX-2 expression has been implicated in the pathophysiology of neuronal cell death. In the present study, we have found that the NO-induced upregulation of COX-2 via activation of activator protein-1 (AP-1) signaling leads to apoptotic cell death. Cultured rat pheochromocytoma (PC12) cells treated with sodium nitroprusside (SNP), a NO-releasing compound, exhibited marked induction of COX-2 expression, which was associated with apoptotic cell death as evidenced by internucleosomal DNA fragmentation, cleavage of poly(ADP-ribose) polymerase, activation of caspase-3, accumulation of p53, increased Bax/Bcl-XL ratio, and dissipation of mitochondrial membrane potential. In addition to the upregulation of COX-2 expression, SNP treatment led to activation of AP-1. Pretreatment of PC12 cells with c-fos antisense oligonucleotide abolished the NO-induced increase in DNA binding of AP-1 and upregulation of COX-2 expression. Furthermore, pretreatment with a selective COX-2 inhibitor (SC58635) rescued the PC12 cells from the apoptotic cell death induced by NO. Similar results were obtained when the NO-induced upregulation of COX-2 expression was blocked by the siRNA interference. These results suggest that excessive NO production during inflammation induces apoptosis in PC12 cells through AP-1-mediated upregulation of COX-2 expression.
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Affiliation(s)
- Mei-Hua Li
- National Research Laboratory of Molecular Carcinogenesis and Chemoprevention, College of Pharmacy, Seoul National University, Shinlim-dong, Kwanak-ku, Seoul 151-742, South Korea
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17
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Klivenyi P, Kiaei M, Gardian G, Calingasan NY, Beal MF. Additive neuroprotective effects of creatine and cyclooxygenase 2 inhibitors in a transgenic mouse model of amyotrophic lateral sclerosis. J Neurochem 2003; 88:576-82. [PMID: 14720207 DOI: 10.1046/j.1471-4159.2003.02160.x] [Citation(s) in RCA: 143] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
There is substantial evidence implicating both inflammation and mitochondrial dysfunction in amyotrophic lateral sclerosis (ALS) pathogenesis. We investigated the therapeutic effects of cyclooxygenase 2 (COX-2) inhibitors both alone and in combination with creatine in the G93A transgenic mouse model of ALS. Oral administration of either celecoxib or rofecoxib significantly improved motor performance, attenuated weight loss and extended survival. The administration of COX-2 inhibitors significantly reduced prostaglandin E2 levels at 110 days of age. The combination of creatine with COX-2 inhibitors produced additive neuroprotective effects and extended survival by approximately 30%. The COX-2 inhibitors significantly protected against depletion of anterior horn motor neurons and creatine with COX-2 inhibitors showed greater protection than COX-2 inhibitors alone. These results suggest that combinations of therapies targeting different disease mechanisms may be a useful strategy in the treatment of ALS.
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Affiliation(s)
- Peter Klivenyi
- Department of Neurology and Neuroscience, New York Presbyterian Hospital-Weill Medical College of Cornell University, New York, New York 10021, USA
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18
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Li RC, Row BW, Gozal E, Kheirandish L, Fan Q, Brittian KR, Guo SZ, Sachleben LR, Gozal D. Cyclooxygenase 2 and intermittent hypoxia-induced spatial deficits in the rat. Am J Respir Crit Care Med 2003; 168:469-75. [PMID: 12773326 DOI: 10.1164/rccm.200211-1264oc] [Citation(s) in RCA: 110] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Intermittent hypoxia (IH) during sleep, a critical feature of sleep apnea, induces significant neurobehavioral deficits in the rat. Cyclooxygenase (COX)-2 is induced during stressful conditions such as cerebral ischemia and could play an important role in IH-induced learning deficits. We therefore examined COX-1 and COX-2 genes and COX-2 protein expression and activity (prostaglandin E2 [PGE2] tissue concentration) in cortical regions of rat brain after exposure to either IH (10% O2 alternating with 21% O2 every 90 seconds) or sustained hypoxia (10% O2). In addition, the effect of selective COX-2 inhibition with NS-398 on IH-induced neurobehavioral deficits was assessed. IH was associated with increased COX-2 protein and gene expression from Day 1 to Day 14 of exposure. No changes were found in COX-1 gene expression after exposure to hypoxia. IH-induced COX-2 upregulation was associated with increased PGE2 tissue levels, neuronal apoptosis, and neurobehavioral deficits. Administration of NS-398 abolished IH-induced apoptosis and PGE2 increases without modifying COX-2 mRNA expression. Furthermore, NS-398 treatment attenuated IH-induced deficits in the acquisition and retention of a spatial task in the water maze. We conclude that IH induces upregulation and activation of COX-2 in rat cortex and that COX-2 may play a role in IH-mediated neurobehavioral deficits.
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Affiliation(s)
- Richard C Li
- Kosair Children's Hospital Research Institute, 570 South Preston Street, Suite 321, Department of Pediatrics, University of Louisville, Louisville, KY 40202, USA
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19
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Abstract
OBJECTIVES Oxidative stress and glutamate-mediated excitotoxicity may play an important role in the etiopathogenesis of amyotrophic lateral sclerosis (ALS). Prostaglandin E2 (PGE2) activity can be associated with motor neuron death by inducing free radical formation and glutamate release from astrocytes. The aim of this study was to determine PGE2 concentration in the serum and cerebrospinal fluid (CSF) of ALS patients. MATERIAL AND METHODS PGE2 concentration was measured by the enzyme-linked immunosorbent method in the serum and CSF from ALS and control group patients. RESULTS Serum and CSF PGE2 concentration was significantly higher in the whole group of ALS patients compared with the control group patients (P < 0.05). There was no relationship between PGE2 concentration and clinical parameters of the disease, such as clinical state, type of ALS onset, and duration of the disease (P > 0.05). A significant correlation between CSF PGE2 concentration and age of control group patients was found (P < 0.05). CONCLUSIONS A significant increase in serum and CSF PGE2 concentration, in ALS patients observed in this study, indicates that PGE2 may play a role in neurodegeneration of ALS through oxidative damage of neurons and glutamate-mediated excitotoxicity. It suggests that inhibition of PGE2 synthesis could prevent motor neuron death. However, serum and CSF PGE2 cannot be a marker of the type of ALS onset, clinical state of patients, or the duration of the disease.
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Affiliation(s)
- J Iłzecka
- Department of Neurology, Medical University, Lublin, Poland
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20
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Yokota O, Terada S, Ishizu H, Ishihara T, Ujike H, Nakashima H, Nakashima Y, Kugo A, Checler F, Kuroda S. Cyclooxygenase-2 in the hippocampus is up-regulated in Alzheimer's disease but not in variant Alzheimer's disease with cotton wool plaques in humans. Neurosci Lett 2003; 343:175-9. [PMID: 12770691 DOI: 10.1016/s0304-3940(03)00339-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
We examined neuronal expression of cyclooxygenase-2, a pro-inflammatory protein, and neuron densities in the CA1-4 of the hippocampus in three cases of Alzheimer's disease with cotton wool plaques (CWP-AD), 17 cases of typical Alzheimer's disease without CWPs (tAD), and 26 normal controls. Cyclooxygenase-2 expression was significantly increased in all of the CA1-4 in tAD, but not in any subdivision in CWP-AD, compared with controls. Cyclooxygenase-2 expression in tAD was also significantly up-regulated compared with that in CWP-AD in all subdivisions. Furthermore, neuron density in the hippocampus was not significantly reduced in CWP-AD cases compared with controls despite remarkable intra- and extraneuronal Abeta deposition. These findings suggest that unknown factors besides Abeta deposition are necessary for the cyclooxygenase-2 up-regulation and neurodegeneration in Alzheimer's disease.
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Affiliation(s)
- Osamu Yokota
- Department of Neuropsychiatry, Okayama University Graduate School of Medicine and Dentistry, Okayama 700-8558, Japan.
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21
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Abstract
The pathogenesis of Parkinson's disease (PD) remains obscure, but there is increasing evidence that impairment of mitochondrial function, oxidative damage, and inflammation are contributing factors. The present paper reviews the experimental and clinical evidence implicating these processes in PD. There is substantial evidence that there is a deficiency of complex I activity of the mitochondrial electron transport chain in PD. There is also evidence for increased numbers of activated microglia in both PD postmortem tissue as well as in animal models of PD. Impaired mitochondrial function and activated microglia may both contribute to oxidative damage in PD. A number of therapies targeting inflammation and mitochondrial dysfunction are efficacious in the MPTP model of PD. Of these, coenzyme Q(10) appears to be particularly promising based on the results of a recent phase 2 clinical trial in which it significantly slowed the progression of PD.
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Affiliation(s)
- M Flint Beal
- Department of Neurology and Neuroscience, Weill Medical College of Cornell University, New York Presbyterian Hospital, New York, New York 10021, USA.
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22
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Moore RM, Silver RJ, Moore JJ. Physiological apoptotic agents have different effects upon human amnion epithelial and mesenchymal cells. Placenta 2003; 24:173-80. [PMID: 12566244 DOI: 10.1053/plac.2002.0886] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Foetal membrane rupture is thought to follow from gene-controlled tissue remodelling and apoptosis. We reported previously that staurosporine, cycloheximide, actinomycin D, as well as more physiological apoptotic agents (lactosylceramide, 15d-PGJ(2)) increase prostaglandin release in parallel with induction of apoptosis in WISH and amnion epithelial cells. Also, inhibition of prostaglandin release by cyclooxygenase inhibitors or PKA activators is accompanied by a parallel decrease in apoptosis. We hypothesize that amnion prostaglandin metabolism is linked with apoptosis in amnion epithelial cells and thus to membrane rupture. Amnion mesenchymal cells are also critical for membrane integrity. Their susceptibility to apoptotic agents is unknown and is the subject of this report. In amnion epithelial cells, lactosylceramide (125 microM) induced 6.5-fold, 20-fold increases in PGE(2) and NMP production (apoptosis), respectively. Conversely, in mesenchymal cells, lactosylceramide doses up to 200 microM had no effect on PGE(2) or NMP release. In both cell types, incubation with 15d-PGJ(2) (5-100 microM) demonstrated dose and time dependent increases in PGE(2) and NMP. PKA activators inhibited 15d-PGJ(2) induced PGE(2) release and apoptotis in epithelial cells, but not in mesenchymal cells, however. Major amnion cell types have different sensitivities to physiological apoptotic agents. Prostaglandin release occurs coincident with apoptosis in both amnion epithelial and mesenchymal cells.
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Affiliation(s)
- R M Moore
- Department of Pediatrics, Case Western Reserve University, Cleveland, OH 44109, USA
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23
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Tu B, Bazan NG. Hippocampal kindling epileptogenesis upregulates neuronal cyclooxygenase-2 expression in neocortex. Exp Neurol 2003; 179:167-75. [PMID: 12618123 DOI: 10.1016/s0014-4886(02)00019-5] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Recurrent and spontaneous seizures in epilepsy result from poorly defined cell signaling aberrations thought to include synaptic and extracellular matrix remodeling. Here we have used a rat hippocampal kindling model to study cyclooxygenase-2 (COX-2) gene expression in epileptogenesis. COX-2, encoded in an early-response gene, increases in a synaptic activity-dependent fashion and also during kainic acid-induced hippocampal damage. We found that during kindling, COX-2 induction occurred initially only in hippocampal neurons, and then spread to neocortical neurons. When rats were rekindled 34 days later, this spreading of COX-2 expression persisted. Induction of hippocampal and neocortical cytosolic phospholipase A(2) (cPLA(2)), an enzyme that catalyzes the synthesis of COX-2 substrate arachidonic acid (AA), occurred after 4 days of stimulation during kindling and rekindling. Moreover the COX-2 selective inhibitor nimesulide attenuated kindling development. We conclude that neuronal COX-2 gene induction and cPLA(2) activation are key signaling events in epileptogenesis.
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Affiliation(s)
- Bin Tu
- Louisiana State University Health Sciences Center, Neuroscience Center of Excellence, New Orleans, LA 70112, USA
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24
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25
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Kim JA, Mitsukawa K, Yamada MK, Nishiyama N, Matsuki N, Ikegaya Y. Cytoskeleton disruption causes apoptotic degeneration of dentate granule cells in hippocampal slice cultures. Neuropharmacology 2002; 42:1109-18. [PMID: 12128012 DOI: 10.1016/s0028-3908(02)00052-7] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Colchicine, a potent microtubule-depolymerizing agent, is well known to selectively kill dentate granule cells in the hippocampal formation in vivo. Using organotypic cultures of rat entorhino-hippocampal slices, we confirmed that in vitro exposure to 1 microM and 10 microM of colchicine reproduced a specific degeneration of the granule cells after 24 h. Similar results were obtained with other types of microtubule-disrupting agents, i.e., nocodazole, vinblastine, and Taxol. Interestingly, the actin-depolymerizing agents cytochalasin D and latrunculin A also elicited selective neurotoxicity in the dentate gyrus without affecting survival of hippocampal pyramidal cells. The selective pattern of degeneration was observable 24 h after a brief treatment with the toxins as short as 5 min, but this delayed neuronal death was unlikely to be a result of excitotoxicity because it was virtually unaffected by glutamate receptor antagonists, tetrodotoxin, or extracellular Ca(2+)-free conditions. The damaged tissues contained a large number of TUNEL-positive neurons and exhibited an increased level in caspase-3-like activity, suggesting that cytoskeleton disruption triggers an apoptosis-like process in dentate granule cells. Thus, this study may provide a basis for understanding the distinctive mechanism that supports granule cell survival.
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Affiliation(s)
- Jeong-Ah Kim
- Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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26
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Geloso MC, Vercelli A, Corvino V, Repici M, Boca M, Haglid K, Zelano G, Michetti F. Cyclooxygenase-2 and caspase 3 expression in trimethyltin-induced apoptosis in the mouse hippocampus. Exp Neurol 2002; 175:152-60. [PMID: 12009767 DOI: 10.1006/exnr.2002.7866] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The neurotoxicant trimethyltin (TMT) induces massive neuronal loss in vivo in the hippocampus of rodents, accompanied by behavioral alterations. The present study investigates the pattern of cell death after in vivo administration of TMT to adult mice. In the granular cell layer of the Dentate Gyrus, TUNEL staining detected DNA fragmentation, and apoptotic bodies were also evident. In addition, a ladder pattern of internucleosomal DNA fragmentation was shown in agarose gel electrophoresis. We show that activated caspase-3, which is known to play a pivotal role in apoptotic processes, is clearly expressed by degenerating neurons. Inducible cyclooxygenase is also expressed at cytoplasmic level by degenerating granular neurons, suggesting that this enzyme may participate in TMT-induced neurodegeneration.
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27
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Abstract
Alzheimer's disease (AD) is a worldwide problem that affects 5 million people in the United States alone. Until the approval of tacrine in the mid-1990s, there was no effective therapy for the cognitive symptoms of AD. Although cholinergic therapy provides modest but significant symptomatic relief, the development of effective disease-modifying therapy is essential. It has been demonstrated that a number of inflammatory processes are active in the brain of patients with AD, and therefore it is believed that an anti-inflammatory regimen may offer some degree of neuroprotection. Several studies have indicated that use of nonsteroidal anti-inflammatory drugs (NSAIDs) is associated with delayed onset and/or slowed cognitive decline in AD. Although not currently approved for this condition, recent findings have demonstrated that cyclooxygenase (COX)-2 is of primary importance in the inflammatory response and may have a role in neurodegeneration. Therefore, selective COX-2 inhibitors (coxibs) may have an advantage over traditional NSAIDs as potential therapeutic agents in AD. The Alzheimer's Disease Cooperative Study (ADCS) is conducting an ongoing multicenter, double-blind, placebo-controlled trial to determine whether rofecoxib, a coxib, or naproxen, a nonselective NSAID, will slow the rate of cognitive and clinical decline in AD. This study, along with other clinical studies currently under way, will determine the utility of selective and nonselective COX inhibitors for the prevention and treatment of AD.
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Affiliation(s)
- Paul S Aisen
- Departments of Neurology and Medicine, Georgetown University Medical Center, Washington, DC 20007, USA
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28
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Candelario-Jalil E, Alvarez D, Castañeda JM, Al-Dalain SM, Martínez-Sánchez G, Merino N, León OS. The highly selective cyclooxygenase-2 inhibitor DFU is neuroprotective when given several hours after transient cerebral ischemia in gerbils. Brain Res 2002; 927:212-5. [PMID: 11821016 DOI: 10.1016/s0006-8993(01)03358-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Several studies suggest that cyclooxygenase-2 contributes to the delayed progression of ischemic brain damage. In this study we examined whether the highly selective cyclooxygenase-2 inhibitor DFU reduces neuronal damage when administered several hours after 5 min of transient forebrain ischemia in gerbils. The extent of ischemic injury was assessed behaviorally by measuring the increases in locomotor activity and by histopathological evaluation of the extent of CA1 hippocampal pyramidal cell injury 7 days after ischemia. DFU treatment (10 mg/kg, p.o.) significantly reduced hippocampal neuronal damage even if the treatment is delayed until 12 h after ischemia. These results suggest that selective cyclooxygenase-2 inhibitors may be a valuable therapeutic strategy for ischemic brain injury.
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Affiliation(s)
- Eduardo Candelario-Jalil
- Department of Pharmacology, University of Havana (CIEB-IFAL), Apartado Postal 6079, Havana City 10600, Cuba.
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29
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Abd-El-Aleem SA, Ferguson MW, Appleton I, Bhowmick A, McCollum CN, Ireland GW. Expression of cyclooxygenase isoforms in normal human skin and chronic venous ulcers. J Pathol 2001; 195:616-23. [PMID: 11745699 DOI: 10.1002/path.992] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Chronic venous ulcers are an example of abnormal wound healing showing chronic inflammation which together with the underlying vascular pathology results in delayed healing. Prostaglandins are among the most important mediators of inflammation. They have proinflammatory effects, predominantly by affecting the vasculature. Cyclooxygenase (COX) is the rate-limiting enzyme in prostanoid synthesis. It is present in two isoforms: COX-1 (constitutive cyclooxygenase) which is produced in the body to maintain normal haemostatic functions, and COX-2 (inducible cyclooxygenase), which is induced during inflammation in response to cytokines. Using immunoenzymatic labelling and western blot analysis, this study has shown that both COX-1 and COX-2 were up-regulated in chronic venous leg ulcers by comparison with normal human skin. De novo appearance of COX-2 in chronic venous ulcers was demonstrated, which is not seen in normal human skin. The main cellular sources of both COX isoforms are macrophages and endothelial cells. COX-2 is also produced by mast cells and fibroblasts. A COX radioimmunoassay showed up-regulation of COX activity in chronic venous ulcers compared with normal skin (p<0.05). Up-regulation of COX-1 in chronic venous leg ulcers could produce prostacyclin, which contributes to angiogenesis. Thus, inhibition of COX-1 by non-steroidal anti-inflammatory drugs (NSAIDs) could increase the local ischaemia and hypoxia associated with chronic venous ulcers. On the other hand, up-regulation of COX-2 is most likely responsible for the persistent inflammation in chronic venous leg ulcers. COX-2 selective inhibitors could therefore be effective in the treatment of chronic venous ulcers.
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Affiliation(s)
- S A Abd-El-Aleem
- School of Biological Sciences, University of Manchester, Room 3.239, Stopford Building, Oxford Road, Manchester M13 9PT, UK
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30
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Fiebich BL, Schleicher S, Spleiss O, Czygan M, Hüll M. Mechanisms of prostaglandin E2-induced interleukin-6 release in astrocytes: possible involvement of EP4-like receptors, p38 mitogen-activated protein kinase and protein kinase C. J Neurochem 2001; 79:950-8. [PMID: 11739606 DOI: 10.1046/j.1471-4159.2001.00652.x] [Citation(s) in RCA: 97] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The expression of cyclooxygenase-2 (COX-2) and the synthesis of prostaglandin E2 (PGE2) as well as of cytokines such as interleukin-6 (IL-6) have all been suggested to propagate neuropathology in different brain disorders such as HIV-dementia, prion diseases, stroke and Alzheimer's disease. In this report, we show that PGE2-stimulated IL-6 release in U373 MG human astroglioma cells and primary rat astrocytes. PGE2-induced intracellular cAMP formation was mediated via prostaglandin E receptor 2 (EP2), but inhibition of cAMP formation and protein kinase A or blockade of EP1/EP2 receptors did not affect PGE2-induced IL-6 synthesis. This indicates that the cAMP pathway is not part of PGE2-induced signal transduction cascade leading to IL-6 release. The EP3/EP1-receptor agonist sulprostone failed to induce IL-6 release, suggesting an involvement of EP4-like receptors. PGE2-activated p38 mitogen-activated kinase (p38 MAPK) and protein kinase C (PKC). PGE2-induced IL-6 synthesis was inhibited by specific inhibitors of p38 MAPK (SB202190) and PKC (GF203190X). Although, up to now, EP receptors have only rarely been linked to p38 MAPK or PKC activation, these results suggest that PGE2 induces IL-6 via an EP4-like receptor by the activation of PKC and p38 MAPK via an EP4-like receptor independently of cAMP.
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Affiliation(s)
- B L Fiebich
- Department of Psychiatry, University of Freiburg Medical School, Freiburg, Germany.
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31
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Gong C, Ennis SR, Hoff JT, Keep RF. Inducible cyclooxygenase-2 expression after experimental intracerebral hemorrhage. Brain Res 2001; 901:38-46. [PMID: 11368948 DOI: 10.1016/s0006-8993(01)02186-2] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Cyclooxygenase-2 (COX-2) is an inducible isoform of cyclooxygenase, which catalyzes the conversion of arachidonic acid to prostaglandins and thromboxane. Recent evidence suggests it has a pathological role in cerebral insults, but its involvement in intracerebral hemorrhage (ICH) is unknown. The present study investigates the temporal and anatomic distribution of COX-2 as well as the effect of the selective COX-2 inhibitor NS-398 on brain edema formation and cerebral blood flow in a rat model of ICH. Immunohistochemistry for COX-2 was performed in control rats and 6 h, as well as 1, 3, 7 and 10 days after the injection of 100 microl autologous blood into the right basal ganglia. Double-labeling immunohistochemistry was used to determine the type of COX-2 immunoreactive microvascular-associated cells. Western blot analysis was used to quantify COX-2 protein. The effect of NS-398 on brain water content, ion concentration and cerebral blood flow were assessed 24 h after ICH. The results demonstrated that COX-2 protein was expressed in control brain tissue and induced significantly in the ipsilateral hemisphere at 6 h, as well as 1 and 3 days after ICH. Increased staining of COX-2 in neurons was observed around the blood clot with a peak at 6 h. COX-2 was induced in endothelial cells, perivascular cells as well as infiltrating leukocytes 1 day after ICH. Brain water and ion contents and cerebral blood flow were unaffected by NS-398 administration. Thus, although COX-2 expression was increased in the ipsilateral hemisphere after an autologous blood injection, its products do not appear to be major regulators of blood flow or edema formation following ICH.
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Affiliation(s)
- C Gong
- Department of Neurosurgery, University of Michigan, Ann Arbor, MI 48109, USA.
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32
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Kim EJ, Lee JE, Kwon KJ, Lee SH, Moon CH, Baik EJ. Differential roles of cyclooxygenase isoforms after kainic acid-induced prostaglandin E(2) production and neurodegeneration in cortical and hippocampal cell cultures. Brain Res 2001; 908:1-9. [PMID: 11457426 DOI: 10.1016/s0006-8993(01)02432-5] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Prostaglandins, which are cyclooxygenase (COX) products, are pathologically up-regulated, and have been proven to be closely associated with neuronal death. In this study, we investigated a role of COX isoforms (COX-1 and COX-2) in kainic acid-induced neuronal death in cultured murine cortical or hippocampal neurons. In primary cortical neurons, both indomethacin (COX-1/-2 nonselective inhibitor) and aspirin (COX-1 preferential inhibitor) reduced basal and kainic acid-induced PGE(2) production significantly and prevented neuronal cell death after kainic acid treatment. In contrast, NS398 (COX-2 selective inhibitor) had no effect on kainic acid-induced neuronal cell death. In hippocampal neurons, however, COX-2 inhibitors prevented both kainic acid-induced neuronal death and PGE(2) production. COX-2 expression was remarkably up-regulated by kainic acid in hippocampal neurons; whereas in cortical neurons, COX-2 expression was comparatively less significant. Astrocytes were unresponsive to kainic acid in terms of PGE(2) production and cell death. In conclusion, we suggest that the release of PGE(2) induced by kainic acid occurred through COX-1 activity rather than COX-2 in cortical neurons. The inhibition of PGE(2) release by COX-1 inhibitors prevented kainic acid-induced cortical neuronal death, while in the hippocampal neurons, COX-2 inhibitors prevented kainic acid-induced PGE(2) release and hippocampal neuronal death.
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Affiliation(s)
- E J Kim
- Department of Physiology, Ajou University School of Medicine, 442-749, Suwon, South Korea
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33
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Aisen PS. Anti-inflammatory therapy for Alzheimer's disease: implications of the prednisone trial. ACTA NEUROLOGICA SCANDINAVICA. SUPPLEMENTUM 2001; 176:85-9. [PMID: 11261810 DOI: 10.1034/j.1600-0404.2000.00312.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The inflammatory hypothesis of Alzheimer's disease (AD), which is supported both by basic laboratory evidence and epidemiological studies, suggests that treatment with anti-inflammatory drugs may reduce the risk or slow the progression of AD. In the first large-scale test of this hypothesis, the Alzheimer's Disease Cooperative Study (ADCS) conducted a randomized placebo-controlled trial of low-dose prednisone treatment in subjects with probable AD. There was no difference in cognitive decline between the prednisone and placebo treatment groups; subjects treated with prednisone showed behavioral decline compared to those in the placebo group. While this study indicates that a low-dose regimen of prednisone is not useful in the treatment of AD, it does not refute the inflammatory hypothesis; recent evidence supports testing of a number of alternative anti-inflammatory regimens, for prevention and/or treatment of AD. The ADCS has initiated a trial to determine whether treatment with a non-selective non-steroidal anti-inflammatory drug or a selective cyclooxygenase-2 inhibitor is effective in slowing the rate of cognitive decline in AD.
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Affiliation(s)
- P S Aisen
- Department of Neurology, Georgetown University Medical Center, Washington, DC 20007, USA.
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34
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Fiebich BL, Mueksch B, Boehringer M, Hüll M. Interleukin-1beta induces cyclooxygenase-2 and prostaglandin E(2) synthesis in human neuroblastoma cells: involvement of p38 mitogen-activated protein kinase and nuclear factor-kappaB. J Neurochem 2000; 75:2020-8. [PMID: 11032891 DOI: 10.1046/j.1471-4159.2000.0752020.x] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Prostaglandins (PGs), which are generated by the enzymatic activity of cyclooxygenase (COX)-1 and -2, modulate several functions in the CNS such as the generation of fever, the sleep/wake cycle, and the perception of pain. Moreover, the neuronal induction of COX-2 has been linked to neuroinflammatory aspects of Alzheimer's disease (AD). The regulation of COX expression in neuronal cells is only partly understood and has been mainly linked to synaptic activity. In pathophysiological situations, however, cytokines may be potent stimulators of neuronal COX expression. Here we show that interleukin (IL)-1beta induces COX-2 mRNA and protein synthesis and the release of PGE(2) in the human neuroblastoma cell line SK-N-SH. We further demonstrate that both a free radical scavenger and an inhibitor of p38 mitogen-activated protein kinase (MAPK) reduce IL-1beta-induced synthesis of COX-2. IL-1beta induces p38 MAPK phosphorylation and activation of the nuclear factor-kappaB independently from each other. Our data suggest that IL-1beta-induced COX-2 expression in SK-N-SH cells is regulated by different mechanisms, presumably involving mRNA transcription and mRNA stability. The ability of p38 MAPK to augment COX-2 expression in human neuroblastoma cells, as shown here, suggests that p38 MAPK may be involved in neuronal expression of COX-2 in AD.
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Affiliation(s)
- B L Fiebich
- Department of Psychiatry, University of Freiburg Medical School, Freiburg, Germany.
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35
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Fosslien E. Biochemistry of cyclooxygenase (COX)-2 inhibitors and molecular pathology of COX-2 in neoplasia. Crit Rev Clin Lab Sci 2000; 37:431-502. [PMID: 11078056 DOI: 10.1080/10408360091174286] [Citation(s) in RCA: 187] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Several types of human tumors overexpress cyclooxygenase (COX) -2 but not COX-1, and gene knockout transfection experiments demonstrate a central role of COX-2 in experimental tumorigenesis. COX-2 produces prostaglandins that inhibit apoptosis and stimulate angiogenesis and invasiveness. Selective COX-2 inhibitors reduce prostaglandin synthesis, restore apoptosis, and inhibit cancer cell proliferation. In animal studies they limit carcinogen-induced tumorigenesis. In contrast, aspirin-like nonselective NSAIDs such as sulindac and indomethacin inhibit not only the enzymatic action of the highly inducible, proinflammatory COX-2 but the constitutively expressed, cytoprotective COX-1 as well. Consequently, nonselective NSAIDs can cause platelet dysfunction, gastrointestinal ulceration, and kidney damage. For that reason, selective inhibition of COX-2 to treat neoplastic proliferation is preferable to nonselective inhibition. Selective COX-2 inhibitors, such as meloxicam, celecoxib (SC-58635), and rofecoxib (MK-0966), are NSAIDs that have been modified chemically to preferentially inhibit COX-2 but not COX-1. For instance, meloxicam inhibits the growth of cultured colon cancer cells (HCA-7 and Moser-S) that express COX-2 but has no effect on HCT-116 tumor cells that do not express COX-2. NS-398 induces apoptosis in COX-2 expressing LNCaP prostate cancer cells and, surprisingly, in colon cancer S/KS cells that does not express COX-2. This effect may due to induction of apoptosis through uncoupling of oxidative phosphorylation and down-regulation of Bcl-2, as has been demonstrated for some nonselective NSAIDs, for instance, flurbiprofen. COX-2 mRNA and COX-2 protein is constitutively expressed in the kidney, brain, spinal cord, and ductus deferens, and in the uterus during implantation. In addition, COX-2 is constitutively and dominantly expressed in the pancreatic islet cells. These findings might somewhat limit the use of presently available selective COX-2 inhibitors in cancer prevention but will probably not deter their successful application for the treatment of human cancers.
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Affiliation(s)
- E Fosslien
- Department of Pathology, College of Medicine, University of Illinois at Chicago, 60612, USA.
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Strauss KI, Barbe MF, Marshall RM, Raghupathi R, Mehta S, Narayan RK. Prolonged cyclooxygenase-2 induction in neurons and glia following traumatic brain injury in the rat. J Neurotrauma 2000; 17:695-711. [PMID: 10972245 PMCID: PMC1456323 DOI: 10.1089/089771500415436] [Citation(s) in RCA: 101] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Cyclooxygenase-2 (COX2) is a primary inflammatory mediator that converts arachidonic acid into precursors of vasoactive prostaglandins, producing reactive oxygen species in the process. Under normal conditions COX2 is not detectable, except at low abundance in the brain. This study demonstrates a distinctive pattern of COX2 increases in the brain over time following traumatic brain injury (TBI). Quantitative lysate ribonuclease protection assays indicate acute and sustained increases in COX2 mRNA in two rat models of TBI. In the lateral fluid percussion model, COX2 mRNA is significantly elevated (>twofold, p < 0.05, Dunnett) at 1 day postinjury in the injured cortex and bilaterally in the hippocampus, compared to sham-injured controls. In the lateral cortical impact model (LCI), COX2 mRNA peaks around 6 h postinjury in the ipsilateral cerebral cortex (fivefold induction, p < 0.05, Dunnett) and in the ipsilateral and contralateral hippocampus (two- and six-fold induction, respectively, p < 0.05, Dunnett). Increases are sustained out to 3 days postinjury in the injured cortex in both models. Further analyses use the LCI model to evaluate COX2 induction. Immunoblot analyses confirm increased levels of COX2 protein in the cortex and hippocampus. Profound increases in COX2 protein are observed in the cortex at 1-3 days, that return to sham levels by 7 days postinjury (p < 0.05, Dunnett). The cellular pattern of COX2 induction following TBI has been characterized using immunohistochemistry. COX2-immunoreactivity (-ir) rises acutely (cell numbers and intensity) and remains elevated for several days following TBI. Increases in COX2-ir colocalize with neurons (MAP2-ir) and glia (GFAP-ir). Increases in COX2-ir are observed in cerebral cortex and hippocampus, ipsilateral and contralateral to injury as early as 2 h postinjury. Neurons in the ipsilateral parietal, perirhinal and piriform cortex become intensely COX2-ir from 2 h to at least 3 days postinjury. In agreement with the mRNA and immunoblot results, COX2-ir appears greatest in the contralateral hippocampus. Hippocampal COX2-ir progresses from the pyramidal cell layer of the CA1 and CA2 region at 2 h, to the CA3 pyramidal cells and dentate polymorphic and granule cell layers by 24 h postinjury. These increases are distinct from those observed following inflammatory challenge, and correspond to brain areas previously identified with the neurological and cognitive deficits associated with TBI. While COX2 induction following TBI may result in selective beneficial responses, chronic COX2 production may contribute to free radical mediated cellular damage, vascular dysfunction, and alterations in cellular metabolism. These may cause secondary injuries to the brain that promote neuropathology and worsen behavioral outcome.
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Affiliation(s)
- K I Strauss
- Department of Neurosurgery, Temple University School of Medicine, Philadelphia, Pennsylvania, USA.
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37
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Abstract
The newly introduced cyclo-oxygenase-2 (COX-2) inhibiting nonsteroidal anti-inflammatory drugs (NSAIDs) have been established as effective agents in treating arthritic conditions, while greatly reducing the gastrointestinal adverse effects of traditional NSAIDs. There are expectations that NSAIDs will be useful in the treatment of Alzheimer's disease (AD), and that COX-2 inhibitors might have a role. However, a recently reported clinical trial of a COX-2 inhibitor in AD indicated that it was neither protective nor did it accelerate the decline. The expectations were based on pathological evidence of inflammatory changes associated with AD lesions and epidemiological evidence of a reduced prevalence of AD in populations taking NSAIDs. They were supported by preliminary evidence showing efficacy of NSAIDs in treating patients with AD. These data are based on the use of traditional NSAIDs. Whether COX-2 inhibitors would be similarly effective was uncertain since COX-2 is constitutively expressed in neurons. Animal experiments suggest that COX-2 may be performing adaptive functions associated with normal neurons and protective functions associated with stressed neurons. These results emphasise that the appropriate target for NSAID trials in AD is COX-1, but they also indicate that there would be no contraindication to the use of those traditional NSAIDs which have mixed COX-1/COX-2 inhibiting activity.
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Affiliation(s)
- P L McGeer
- Department of Psychiatry, University of British Columbia, Vancouver, Canada.
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Koyfman L, Kaplanski J, Artru AA, Talmor D, Rubin M, Shapira Y. Inhibition of cyclooxygenase 2 by nimesulide decreases prostaglandin E2 formation but does not alter brain edema or clinical recovery after closed head injury in rats. J Neurosurg Anesthesiol 2000; 12:44-50. [PMID: 10636620 DOI: 10.1097/00008506-200001000-00009] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Recently, the enzyme cyclooxygenase (COX) has been recognized to exist as constitutive (COX-1) and inducible isoforms (COX-2). In previous studies, drugs that were inhibitors of both COX-1 and COX-2 failed to decrease brain edema formation or improve Neurological Severity Score (NSS) after closed head trauma (CHT), although some did decrease prostaglandin-E2 (PGE2) formation. The present study examined whether or not a specific inhibitor of COX-2 (nimesulide) exerts a beneficial effect after CHT in rats. Halothane-anesthetized rats (n = 8 in each group) were randomly assigned to one of four groups: surgery, no CHT, no drug (group 1); surgery, no CHT, nimesulide 30 mg/kg intraperitoneally (IP) (group 2); surgery, CHT, no drug (group 3); and surgery, CHT, nimesulide 30 mg/kg IP (group 4). NSS was determined at 1 and 24 h, and brain tissue PGE2 concentration and water content were determined after killing at 24 h. Treatment with nimesulide did not improve NSS (NSS at 24 h = 11+/-6 [median +/- range] in group 3 and 12+/-4 in group 4) or edema formation (brain water content at 24 h = 84.3+/-1.8% [mean +/- SD] in group 3 and 83.8+/-1.9% in group 4). However, nimesulide did decrease cortical and hypothalamic PGE2 formation by 41% and 47%, respectively during the first hour of incubation after brain tissue sampling. The authors conclude that although nimesulide does reduce tissue PGE2 formation, it does not exert a beneficial effect on brain tissue edema or functional activity after CHT in rats.
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Affiliation(s)
- L Koyfman
- Division of Anesthesiology, Soroka Medical Center, Faculty of Health Science, Ben Gurion University of the Negev, Beer-Sheva, Israel
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Kelley KA, Ho L, Winger D, Freire-Moar J, Borelli CB, Aisen PS, Pasinetti GM. Potentiation of excitotoxicity in transgenic mice overexpressing neuronal cyclooxygenase-2. THE AMERICAN JOURNAL OF PATHOLOGY 1999; 155:995-1004. [PMID: 10487857 PMCID: PMC1866889 DOI: 10.1016/s0002-9440(10)65199-1] [Citation(s) in RCA: 176] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
In this study we describe the generation of a transgenic mouse model with neuronal overexpression of the human cyclooxygenase-2, h(COX)-2, to explore its role in excitotoxicity. We report that overexpression of neuronal hCOX-2 potentiates the intensity and lethality of kainic acid excitotoxicity in coincidence with potentiation of expression of the immediate early genes c-fos and zif-268. In vitro studies extended the in vivo findings and revealed that glutamate excitotoxicity is potentiated in primary cortico-hippocampal neurons derived from hCOX-2 transgenic mice, possibly through potentiation of mitochondrial impairment. This study is the first to demonstrate a cause-effect relationship between neuronal COX-2 expression and excitotoxicity. This model system will allow the systematic examination of the role of COX-2 in mechanisms of neurodegeneration that involve excitatory amino acid pathways.
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Affiliation(s)
- K A Kelley
- Neuroinflammation Research Laboratories, Department of Psychiatry, Brookdale Center for Developmental and Molecular Biology, Mount Sinai School of Medicine, New York, New York, USA
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Ho L, Pieroni C, Winger D, Purohit DP, Aisen PS, Pasinetti GM. Regional distribution of cyclooxygenase-2 in the hippocampal formation in Alzheimer's disease. J Neurosci Res 1999; 57:295-303. [PMID: 10412020 DOI: 10.1002/(sici)1097-4547(19990801)57:3<295::aid-jnr1>3.0.co;2-0] [Citation(s) in RCA: 175] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Cyclooxygenase-2 (COX-2), a key enzyme in prostanoid biosynthesis, may represent an important therapeutic target in Alzheimer's disease (AD). In the present study, we explored the regulation of COX-2 in the hippocampal formation in sporadic AD. Using semiquantitative immunocytochemical techniques, we found that in AD cases (vs. age-matched controls) neurons of the CA1-CA4 subdivisions of the hippocampal pyramidal layer showed elevation of COX-2 signal; COX-2 levels correlated with amyloid plaque density. In contrast, the level of COX-2 immunostaining in the dentate gyrus granule neurons was not elevated in AD. No expression of COX-2 in cells with glial morphology was found in any case examined. In parallel, in vitro studies found that neurons derived from transgenic mice with neuronal overexpression of COX-2 are more susceptible to beta-amyloid (Abeta) toxicity, with potentiation of redox impairment. The results indicate elevated expression of neuronal COX-2 in subregions of the hippocampal formation in AD and that such elevation may potentiate Abeta-mediated oxidative stress.
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Affiliation(s)
- L Ho
- Neuroinflammation Research Laboratories of the Department of Psychiatry, The Mount Sinai School of Medicine, New York, New York 10029, USA.
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Yasojima K, Schwab C, McGeer EG, McGeer PL. Distribution of cyclooxygenase-1 and cyclooxygenase-2 mRNAs and proteins in human brain and peripheral organs. Brain Res 1999; 830:226-36. [PMID: 10366679 DOI: 10.1016/s0006-8993(99)01389-x] [Citation(s) in RCA: 186] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
We used the techniques of reverse transcriptase-polymerase chain reaction, Western blotting and immunohistochemistry to evaluate the expression of cyclooxygenase (COX)-1 and -2 in brain and peripheral organs of Alzheimer disease (AD) and control cases. We found both COX-1 and COX-2 to be constitutively expressed in all organs tested, i.e., brain, heart, liver, kidney, spleen and intestine. COX-2 was substantially upregulated in affected areas of AD brain and in infarcted areas of human heart. COX-1 was only mildly upregulated in AD brain. Immunohistochemically, COX-2 was strongly expressed in the perinuclear, dendritic and axonal areas of pyramidal neurons, with enhanced staining in AD. These data suggest a special role for COX-2 in neuronal function.
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Affiliation(s)
- K Yasojima
- Kinsmen Laboratory of Neurological Research, Department of Psychiatry, University of British Columbia, 2255 Westbrook Mall, Vancouver, B.C., Canada
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42
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Abstract
Many epidemiological studies suggest that use of non-steroidal anti-inflammatory drugs (NSAIDs) delay or slow the clinical expression of Alzheimer's disease (AD). While it has been demonstrated that neurodegeneration in AD is accompanied by specific inflammatory mechanisms, including activation of the complement cascade and the accumulation and activation of microglia, the mechanism by which NSAIDs might affect these or other pathophysiological processes relevant to AD has been unclear. New evidence that cyclooxygenase (COX) is involved in neurodegeneration along with the development of selective COX inhibitors has led to renewed interest in the therapeutic potential of NSAIDs in AD.
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Affiliation(s)
- G M Pasinetti
- Department of Psychiatry, Brookdale Center for Molecular Biology and Fishberg Center for Neurobiology, The Mount Sinai School of Medicine, New York, NY, USA
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