451
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García-García F, Ponce S, Brown R, Cussen V, Krueger JM. Sleep disturbances in the rotenone animal model of Parkinson disease. Brain Res 2005; 1042:160-8. [PMID: 15854587 DOI: 10.1016/j.brainres.2005.02.036] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2004] [Revised: 02/09/2005] [Accepted: 02/12/2005] [Indexed: 12/21/2022]
Abstract
Parkinson disease (PD) is characterized by the degeneration of dopaminergic neurons in the substantia nigra pars compacta (SNc) and the presence of intracytoplasmatic inclusions known as Lewy bodies. Chronic administration of rotenone (RT) produces Parkinson's-like symptoms in rats. Because PD patients have disrupted sleep patterns, we determined if chronic RT administration produces similar changes in rat sleep. RT was administered for 28 days to rats. Basal and vehicle (VH) rats received saline or dimethyl sulfoxide and polyethylene glycol (1:1), respectively. VH infusion induced a progressive decrease in non-rapid eye movement sleep (NREMS) during the 4-week period of VH infusion and REMS was reduced in the third and fourth week of VH infusion. VH infusion did not induce dopaminergic cell degeneration. Rats receiving RT infusion also showed decreased NREMS during the treatment. REMS was dramatically reduced on day 7 although subsequently on days 13 and 20 REMS was similar to basal values. After 4 weeks of RT infusion, time in REMS was decreased again. In RT-treated rats, progressive dopaminergic cell degeneration occurred in the SNc. After 4 weeks of daily injections of L-dopa in RT-infused rats, NREMS values remained similar to those values obtained after RT alone. L-dopa therapy did, however, induce a recovery of REMS in weeks 3 and 4 of RT infusion. Dopaminergic cell damage persisted in the L-dopa-RT-infused rats. We conclude that the RT-PD rat model is associated with large long-term sleep disruption, however, the vehicle, DMSO/PEG had as large an effect as RT on sleep, thus changes in sleep cannot be ascribed to loss of dopaminergic cells. Such results question the validity of the RT-PD rat model.
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Affiliation(s)
- Fabio García-García
- Department of Veterinary and Comparative Anatomy, Pharmacology and Physiology, Washington State University, 205 Wegner Hall, Pullman, WA 99164-6520, USA
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452
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Lund S, Porzgen P, Mortensen AL, Hasseldam H, Bozyczko-Coyne D, Morath S, Hartung T, Bianchi M, Ghezzi P, Bsibsi M, Dijkstra S, Leist M. Inhibition of microglial inflammation by the MLK inhibitor CEP-1347. J Neurochem 2005; 92:1439-51. [PMID: 15748162 DOI: 10.1111/j.1471-4159.2005.03014.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
CEP-1347 is a potent inhibitor of the mixed lineage kinases (MLKs), a distinct family of mitogen-activated protein kinase kinase kinases (MAPKKK). It blocks the activation of the c-Jun/JNK apoptotic pathway in neurons exposed to various stressors and attenuates neurodegeneration in animal models of Parkinson's disease (PD). Microglial activation may involve kinase pathways controlled by MLKs and might contribute to the pathology of neurodegenerative diseases. Therefore, the possibility that CEP-1347 modulates the microglial inflammatory response [tumour necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), and monocyte chemotactic protein-1 (MCP-1)] was explored. Indeed, the MLK inhibitor CEP-1347 reduced cytokine production in primary cultures of human and murine microglia, and in monocyte/macrophage-derived cell lines, stimulated with various endotoxins or the plaque forming peptide Abeta1-40. Moreover, CEP-1347 inhibited brain TNF production induced by intracerebroventricular injection of lipopolysaccharide in mice. As expected from a MLK inhibitor, CEP-1347 acted upstream of p38 and c-Jun activation in microglia by dampening the activity of both pathways. These data imply MLKs as important, yet unrecognized, modulators of microglial inflammation, and demonstrate a novel anti-inflammatory potential of CEP-1347.
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Affiliation(s)
- Søren Lund
- Disease Biology, H. Lundbeck A/S, Ottiliavej 9, 2500 Valby, Denmark.
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453
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Sattayaprasert P, Choi HB, Chongthammakun S, McLarnon JG. Platelet-activating factor enhancement of calcium influx and interleukin-6 expression, but not production, in human microglia. J Neuroinflammation 2005; 2:11. [PMID: 15833109 PMCID: PMC1097754 DOI: 10.1186/1742-2094-2-11] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2005] [Accepted: 04/15/2005] [Indexed: 11/10/2022] Open
Abstract
Calcium-sensitive fluorescence microscopy and molecular biology analysis have been used to study the effects of platelet-activating factor (PAF) on intracellular calcium [Ca2+]i and IL-6 expression in human microglia. PAF (applied acutely at 100 nM) elicited a biphasic response in [Ca2+]i consisting of an initial rapid increase of [Ca2+]i due to release from internal stores, followed by a sustained influx. The latter phase of the [Ca2+]i increase was blocked by SKF96365, a non-selective store-operated channel (SOC) inhibitor. RT-PCR analysis showed PAF treatment of microglia induced expression of the pro-inflammatory cytokine IL-6 in a time-dependent manner which was blocked in the presence of SKF96365. However, ELISA assay showed no production of IL-6 was elicited at any time point (1–24 h) for microglial exposures to PAF. These findings suggest that PAF stimulation of human microglia induces expression, but not production, of IL-6 and that SOC-mediated [Ca2+]i influx contributes to the enhanced expression of the cytokine.
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Affiliation(s)
- Prasongchai Sattayaprasert
- Department of Pharmacology and Therapeutics, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
- Department of Anatomy, Mahidol University, Bangkok, Thailand
| | - Hyun B Choi
- Department of Pharmacology and Therapeutics, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
- Division of Neurology, Department of Medicine, University of British Columbia, Canada
| | | | - James G McLarnon
- Department of Pharmacology and Therapeutics, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
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454
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Bolin LM, Zhaung A, Strychkarska-Orczyk I, Nelson E, Huang I, Malit M, Nguyen Q. Differential inflammatory activation of IL-6 (−/−) astrocytes. Cytokine 2005; 30:47-55. [PMID: 15804595 DOI: 10.1016/j.cyto.2004.11.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2004] [Revised: 11/22/2004] [Accepted: 11/29/2004] [Indexed: 10/25/2022]
Abstract
IL-6 is a major immunomodulatory cytokine with neuroprotective activity. The absence of interleukin-6 (IL-6) results in increased vulnerability of dopaminergic neurons to the neurotoxicant, MPTP, and a compromised reactive microgliosis. To determine how astrogliosis may contribute to nigrostriatal degeneration in IL-6 (-/-) mice, the inflammatory profiles of astrocytes of IL-6 genotype were compared. Fourteen cytokines and four chemokines were simultaneously assayed in the supernatants of LPS-stimulated primary astrocyte cultures. In a time course of 6, 18 and 48 h and LPS stimulations of 0, 0.1, 1, 10 and 100 ng/ml, IL-6 (-/-) astrocytes secreted significantly greater amounts of the pro-inflammatory cytokines IL-1alpha, IL-1beta and TNFalpha than did IL-6 (+/+) cells. Elevated levels of IL-10 and IL-12p40 were only detected at 48 h post-stimulation with greater IL-10 in IL-6 (-/-) supernatants and greater IL-12p40 in IL-6 (+/+) supernatants. IL-6 (+/+) astrocytes produced more G-CSF and GM-CSF when compared with IL-6 (-/-) astrocytes. Chemokine levels were greater in supernatants of IL-6 (+/+) astrocytes than IL-6 (-/-) cells prior to 48 h post-stimulation. At that time, higher levels of MIP-1alpha were maintained in IL-6 (+/+) supernatant, while similar levels of MCP-1 in supernatants of both IL-6 (+/+) and IL-6 (-/-) cells were measured. Additionally, LPS (100 ng/ml) resulted in greater levels of KC and Rantes in IL-6 (-/-) astrocyte supernatants compared with IL-6 (+/+) supernatants at that time. These results suggest that the autocrine modulatory activities of IL-6 affect multiple cytokine secretory pathways, which could participate in neurodegenerative processes.
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Affiliation(s)
- L M Bolin
- The Parkinson's Institute, 1170 Morse Avenue, Sunnyvale, CA 94089-1605, USA.
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455
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Marchetti B, Serra PA, Tirolo C, L'episcopo F, Caniglia S, Gennuso F, Testa N, Miele E, Desole S, Barden N, Morale MC. Glucocorticoid receptor–nitric oxide crosstalk and vulnerability to experimental parkinsonism: pivotal role for glia–neuron interactions. ACTA ACUST UNITED AC 2005; 48:302-21. [PMID: 15850669 DOI: 10.1016/j.brainresrev.2004.12.030] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2004] [Accepted: 12/09/2004] [Indexed: 12/19/2022]
Abstract
Inflammation and oxidative stress have been closely associated with the pathogenesis of neurodegenerative disorders, including Parkinson's disease (PD). The expression of inducible nitric oxide synthase (iNOS) in astrocytes and microglia and the production of large amounts of nitric oxide (NO) are thought to contribute to dopaminergic neuron demise. Increasing evidence, however, indicates that activated astroglial cells play key roles in neuroprotection and can promote recovery of CNS functions. Endogenous glucocorticoids (GCs) via glucocorticoid receptors (GRs) exert potent anti-inflammatory and immunosuppressive effects and are key players in protecting the brain against stimulation of innate immunity. Here we review our work showing that exposure to a dysfunctional GR from early embryonic life in transgenic (Tg) mice expressing GR antisense RNA represents a key vulnerability factor in the response of nigrostriatal dopaminergic neurons to the neurotoxin, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), and further report that exacerbation of dopaminergic neurotoxicity with no recovery is determined by failure of astroglia to exert neuroprotective effects. Aberrant iNOS gene expression and increased glia vulnerability to cell death characterized the response of GR-deficient mice to stimulation of innate immunity. More importantly, GR-deficient glial cells failed to protect fetal dopaminergic neurons against oxidative stress-induces cell death, whereas wild-type glia afforded neuroprotection. Thus, lack of iNOS/NO regulation by GCs can program an aberrant GR-NO crosstalk in turn responsible for loss of astroglia neuroprotective function in response to stimulation of innate immunity, pointing to glia and efficient GR-NO dialogue as pivotal factors orchestrating neuroprotection in experimental parkinsonism.
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Affiliation(s)
- Bianca Marchetti
- Neuropharmacology Section, OASI Institute for Research and Care on Mental Retardation and Brain Aging (IRCCS), Troina (EN) Italy.
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456
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Iczkiewicz J, Rose S, Jenner P. Increased osteopontin expression following intranigral lipopolysaccharide injection in the rat. Eur J Neurosci 2005; 21:1911-20. [PMID: 15869484 DOI: 10.1111/j.1460-9568.2005.04009.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Nigral cell death in Parkinson's disease is characterized by glial cell activation leading to inflammatory changes. Osteopontin (OPN) is a glycosylated phosphoprotein that is induced by inflammatory mediators and which we have previously shown to be present in the substantia nigra. However, the role of OPN in the nigral inflammation is not known. We now report on the effects of lipopolysaccharide (LPS)-induced glial cell activation in the substantia nigra of rats on OPN expression. LPS administration induced dopaminergic cell death as shown by reduced nigral tyrosine hydroxylase immunoreactivity. There was a corresponding time-dependent increase in both OPN mRNA, which was maximal at 48 h, and protein levels, which peaked at 72 h before returning to control levels by 120 h. This increase was accompanied by marked reactive gliosis as shown by increased OX-42, glial fibrillary acidic protein (GFAP) and ED1 immunoreactivity. OX-42-positive cells increased in a time-dependent manner, peaking at 72 h before returning to control levels at 120 h. Similarly, ED1-positive cells were present in their greatest numbers at 24 h but then gradually declined. These changes mirrored the alterations occurring in OPN protein and OPN mRNA, respectively. In contrast, GFAP-positive cells only started to increase in number at 120 h. Colocalization studies showed that OPN was present in both ED1- and OX-42-positive cells but not in GFAP-positive cells. These data confirm that intranigral injection of LPS induces a rapid and marked gliosis that accompanies the loss of tyrosine hydroxylase-positive neurones and suggest that, after glial cell activation, enhanced expression of OPN occurs linked to increased numbers of microglia and/or macrophages. This suggests that OPN may be functionally important in the control of inflammatory changes.
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Affiliation(s)
- Joanna Iczkiewicz
- Neurodegenerative Diseases Research Centre, Guy's, King's and St Thomas School of Biomedical Sciences, King's College, London SE1 1UL, UK
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457
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Ouchi Y, Yoshikawa E, Sekine Y, Futatsubashi M, Kanno T, Ogusu T, Torizuka T. Microglial activation and dopamine terminal loss in early Parkinson's disease. Ann Neurol 2005; 57:168-75. [PMID: 15668962 DOI: 10.1002/ana.20338] [Citation(s) in RCA: 607] [Impact Index Per Article: 31.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Neuroinflammatory glial response may contribute to degenerative processes in Parkinson's disease (PD). To investigate changes in microglial activity associated with changes in the presynaptic dopamine transporter density in the PD brain in vivo, we studied 10 early-stage drug-naive PD patients twice using positron emission tomography with a radiotracer for activated microglia [(11)C](R)-PK11195 and a dopamine transporter marker [(11)C]CFT. Quantitative levels of binding potentials (BPs) of [(11)C](R)-PK11195 and [(11)C]CFT in the nigrostriatal pathway were estimated by compartment analyses. The levels of [(11)C](R)-PK11195 BP in the midbrain contralateral to the clinically affected side were significantly higher in PD than that in 10 age-matched healthy subjects. The midbrain [(11)C](R)-PK11195 BP levels significantly correlated inversely with [(11)C]CFT BP in the putamen and correlated positively with the motor severity assessed by the Unified Parkinson's Disease Rating Scale in PD. In healthy subjects, the [(11)C](R)-PK11195 BP in the thalamus and midbrain showed an age-dependent increase. In vivo demonstration of parallel changes in microglial activation and corresponding dopaminergic terminal loss in the affected nigrostriatal pathway in early PD supports that neuroinflammatory responses by intrinsic microglia contribute significantly to the progressive degeneration process of the disease and suggests the importance of early therapeutic intervention with neuroprotective drugs.
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Affiliation(s)
- Yasuomi Ouchi
- Positron Medical Center, Hamamatsu Medical Center, Hamakita, Japan.
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458
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Yao HH, Ding JH, Zhou F, Wang F, Hu LF, Sun T, Hu G. Enhancement of glutamate uptake mediates the neuroprotection exerted by activating group II or III metabotropic glutamate receptors on astrocytes. J Neurochem 2005; 92:948-61. [PMID: 15686497 DOI: 10.1111/j.1471-4159.2004.02937.x] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
We investigated whether the activation of astroglial group II and III metabotropic glutamate receptors (mGluRs) could exert neuroprotective effects and whether the neuroprotection was related to glutamate uptake. Our results showed that the activation of astroglial group II or III mGluRs exerted neuroprotection against 1-methyl-4-phenylpyridinium (MPP+) astroglial conditioned medium-induced neurotoxicity in midbrain neuron cultures. Furthermore, MPP+ decreased glutamate uptake of primary astrocytes and C6 glioma cells, which was recovered by activating group II or III mGluRs. Specific group II or III mGluRs antagonists completely abolished the neuroprotective effects and the enhancement of glutamate uptake of their respective agonists. Our results showed that the primary cultured rat astrocytes and C6 glioma cells expressed receptor proteins for group II mGluR2/3, group III mGluR4, mGluR6 and mGluR7. C6 glioma cells expressed mRNA for group II mGluR3, group III mGluR4, mGluR6, mGluR7 and mGluR8. In conclusion, we confirmed that the activation of astroglial mGluRs exerted neuroprotection, and demonstrated that the mechanism underlying this protective role was at least partially related to the enhancement of glutamate uptake.
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Affiliation(s)
- Hong-Hong Yao
- Department of Pharmacology & Neurobiology, Nanjing Medical University, Nanjing City, Jiangsu Province, China
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459
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Tomás-Camardiel M, Venero JL, Herrera AJ, De Pablos RM, Pintor-Toro JA, Machado A, Cano J. Blood-brain barrier disruption highly induces aquaporin-4 mRNA and protein in perivascular and parenchymal astrocytes: Protective effect by estradiol treatment in ovariectomized animals. J Neurosci Res 2005; 80:235-46. [PMID: 15772982 DOI: 10.1002/jnr.20443] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Strong evidence involves aquaporin-4 (AQP4) in the physiopathology of brain edema. Two major points remain unsolved: (1) the capacity of perivascular glial cells to regulate AQP4 in response to disruption of the blood-brain barrier (BBB); and (2) the potential beneficial role of AQP4 in the clearance of brain edema. We used intraparenchymal injection of lipopolysaccharide (LPS) as an efficient model to induce BBB disruption. This was monitored by IgG extravasation and AQP4 was studied at the mRNA and protein level. The first signs of BBB disruption coincided with strong induction of AQP4 mRNA in perivascular glial cells. At the early phase, estradiol treatment highly prevented the LPS-induced disruption of the BBB and the induction of AQP4. Efficient clearance of vasogenic edema is supposed to occur once BBB is restored. This phase coincided with high induction of AQP4 mRNA in parenchymal reactive astrocytes and perivascular glial processes. High levels of AQP4 mRNA may be beneficial under these conditions. Our data may clarify why estradiol treatment reduces mortality in conditions typically associated with edema formation, like stroke.
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Affiliation(s)
- M Tomás-Camardiel
- Departamento de Bioquímica, Bromatología, Toxicología y Medicina Legal, Facultad de Farmacia, Universidad de Sevilla, Sevilla, Spain
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460
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Kang G, Kong PJ, Yuh YJ, Lim SY, Yim SV, Chun W, Kim SS. Curcumin suppresses lipopolysaccharide-induced cyclooxygenase-2 expression by inhibiting activator protein 1 and nuclear factor kappab bindings in BV2 microglial cells. J Pharmacol Sci 2005; 94:325-8. [PMID: 15037818 DOI: 10.1254/jphs.94.325] [Citation(s) in RCA: 132] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Inflammation is a significant component of chronic neurodegenerative diseases. Cyclooxygenase-2 (COX-2) is expressed in activated microglial cells and appears to be an important source of prostaglandins during inflammatory conditions. To investigate the effect of curcumin on COX-2 gene expression in microglial cells, we treated lipopolysaccharide (LPS)-challenged BV2 microglial cells with various concentrations of curcumin. Curcumin significantly inhibited LPS-mediated induction of COX-2 expression in both mRNA and protein levels in a concentration-dependent manner. COX-2 enzyme activity was also inhibited in accordance with mRNA and protein levels. Furthermore, curcumin markedly inhibited LPS-induced nuclear factor kappaB (NF-kappaB) and activator protein 1 (AP-1) DNA bindings. These data suggest that curcumin suppresses LPS-induced COX-2 gene expression by inhibiting NF-kappaB and AP-1 DNA bindings in BV2 microglial cells.
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Affiliation(s)
- Gu Kang
- Department of Pathology, College of Medicine, Kangwon National University, Chunchon, South Korea
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461
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Yanpallewar S, Rai S, Kumar M, Chauhan S, Acharya SB. Neuroprotective effect of Azadirachta indica on cerebral post-ischemic reperfusion and hypoperfusion in rats. Life Sci 2005; 76:1325-38. [PMID: 15670613 DOI: 10.1016/j.lfs.2004.06.029] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2004] [Accepted: 06/28/2004] [Indexed: 10/25/2022]
Abstract
We assessed the effect of Azadirachta indica (A. indica), a plant that has been reported to possess antioxidant, anti-inflammatory and anxiolytic properties, on cerebral reperfusion injury and long term cerebral hypoperfusion. When blood flow to brain region that has undergone critical period of ischemia is re-established, additional injury is to be expected from the reperfusion. In the present study, bilateral common carotid artery (BCCA) occlusion for 30 min followed by 45 min reperfusion resulted in increase in lipid peroxidation, superoxide dismutase (SOD) activity and fall in total tissue sulfhydryl (T-SH) groups. A. indica pretreatment (500 mg/kg/day x 7 days) attenuated the reperfusion induced enhanced lipid peroxidation, SOD activity and prevented fall in T-SH groups. Moreover, A.indica per se increased brain ascorbic acid level, which was unchanged during reperfusion insult. Long-term cerebral hypoperfusion induced by permanent BCCA occlusion has been reported to cause behavioral and histopathological abnormalities. In the present study, as tested by open field paradigm and Morris' water maze, a propensity towards anxiety and disturbances of learning/memory were observed in animals subjected to hypoperfusion for 2 weeks. A. indica (500 mg/kg/day x 15 days) significantly reduced these hypoperfusion induced functional disturbances. Reactive changes in brain histology like gliosis, perivascular lymphocytic infiltration, recruitment of macrophages and cellular edema following long term hypoperfusion were also attenuated effectively by A. indica. We conclude that our study provides an experimental evidence for possible neuroprotective potentiality of A. indica.
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Affiliation(s)
- Sudhirkumar Yanpallewar
- Department of Pharmacology, Institute of Medical Sciences, Banaras Hindu University, Varanasi, Uttar Pradesh 221 005, India
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462
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Wang X, Chen S, Ma G, Ye M, Lu G. Genistein protects dopaminergic neurons by inhibiting microglial activation. Neuroreport 2005; 16:267-70. [PMID: 15706233 DOI: 10.1097/00001756-200502280-00013] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Inflammation participates in the pathogenesis and progression of Parkinson's disease, in which microglia play a key role. Inhibition of microglia activation has been shown to attenuate inflammation-mediated dopaminergic neurodegeneration. In this study, we found that genistein, the primary soybean isoflavone, concentration-dependently attenuated the lipopolysaccharide-induced decrease in dopamine uptake and loss of tyrosine hydroxylase-immunoreactive neurons in rat mesencephalic neuron-glia cultures. Genistein also inhibited lipopolysaccharide-induced microglia activation and production of tumor necrosis factor-alpha, nitric oxide and superoxide in mesencephalic neuron-glia cultures and microglia-enriched cultures. Our results indicate that genistein may protect dopaminergic neurons from lipopolysaccharide-induced injury and its effective inhibition of microglia activation may be one of the mechanisms.
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Affiliation(s)
- Xijin Wang
- Department of Neurology & Institute of Neurology, Ruijin Hospital, Shanghai Second Medical University, Shanghai 200025, China
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463
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Campbell A, Oldham M, Becaria A, Bondy SC, Meacher D, Sioutas C, Misra C, Mendez LB, Kleinman M. Particulate matter in polluted air may increase biomarkers of inflammation in mouse brain. Neurotoxicology 2005; 26:133-40. [PMID: 15527881 DOI: 10.1016/j.neuro.2004.08.003] [Citation(s) in RCA: 290] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2004] [Accepted: 08/11/2004] [Indexed: 11/21/2022]
Abstract
The etiology of neurodegenerative disorders is at present unknown. However, many of these disorders are associated with an increase in oxidative and inflammatory events. Although a small percentage of these disorders are familial cases linked to specific genetic defects, most are idiopathic. Thus, environmental factors are thought to play an important role in the onset and progression of such disorders. We have demonstrated that exposure (4 h, 5 days per week for 2 weeks) to concentrated airborne particulate matter increases inflammatory indices in brain of ovalbumin-sensitized BALB/c mice. Animals were divided into three exposure groups: filtered air (control), ultrafine particles, or fine and ultrafine particles. The levels of proinflammatory cytokines interleukin-1 alpha (IL-1alpha) and tumor necrosis factor alpha (TNF-alpha) were increased in brain tissue of mice exposed to particulate matter compared to that of control animals. Levels of the immune-related transcription factor NF-kappaB were also found to be substantially elevated in the brain of exposed groups compared with the control group. These data indicate that components of inhaled particulate matter may trigger a proinflammatory response in nervous tissue that could contribute to the pathophysiology of neurodegenerative diseases.
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Affiliation(s)
- A Campbell
- Department of Community and Environmental Medicine, University of California, Irvine, CA 92697-1825, USA.
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464
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Okuno T, Nakatsuji Y, Kumanogoh A, Moriya M, Ichinose H, Sumi H, Fujimura H, Kikutani H, Sakoda S. Loss of dopaminergic neurons by the induction of inducible nitric oxide synthase and cyclooxygenase-2 via CD40: Relevance to Parkinson's disease. J Neurosci Res 2005; 81:874-82. [PMID: 16041799 DOI: 10.1002/jnr.20599] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
A glial reaction associated with up-regulation of inflammatory molecules has been suggested to play an important role in dopaminergic neuron loss in Parkinson's disease (PD). Among inflammatory molecules, inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) have been focused upon as key factors in the pathogenesis. However, the mechanism of how these molecules are induced in PD brains is not clearly understood. We focused on CD 40, which is expressed on neural cells and could be implicated in the neuroinflammation by inducing inflammatory molecules. We showed that both iNOS and COX-2 were up-regulated in microglia and astrocytes by CD 40 stimulation in association with a low dose of interferon-gamma (IFN-gamma) in vitro. Selective loss of dopaminergic neurons was induced by costimulation with CD 40 and IFN-gamma in mesencephalic cultures, which was protected by selective inhibitors of iNOS and/or COX-2. We also found in CD 40-stimulated astrocytes an increase of a low-affinity IgE receptor CD 23, which is known to induce iNOS expression. Together these data suggest that up-regulated iNOS and COX-2 via the CD 40 pathway may lead to dopaminergic neuron loss and may participate in the neuroinflammaory pathway of PD.
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Affiliation(s)
- Tatsusada Okuno
- Department of Neurology, Osaka University Graduate School of Medicine, Osaka, Japan
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465
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Liu X, Fan XL, Zhao Y, Luo GR, Li XP, Li R, Le WD. Estrogen provides neuroprotection against activated microglia-induced dopaminergic neuronal injury through both estrogen receptor-α and estrogen receptor-β in microglia. J Neurosci Res 2005; 81:653-65. [PMID: 16013043 DOI: 10.1002/jnr.20583] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Estrogen provides neuroprotection against neurodegenerative diseases, including Parkinson's disease. Its effects may stem from interactions with neurons, astrocytes, and microglia. We demonstrate here in primary cultures of rat mesencephalic neurons that estrogen protects them from injury induced by conditioned medium obtained from lipopolysaccharide (LPS)-activated microglia. LPS-induced nitrite production and tumor necrosis factor-alpha up-regulation in microglia were blocked by estrogen pretreatment. Estrogen neuroprotection was related to microglial activation of estrogen receptors (ERs), insofar as the protective effect of the microglia-conditioned medium was overridden by pretreatment of microglia with the ER antagonist ICI 182,780. On the other hand, the specific ERalpha antagonist, MPP dihydrochloride, only partially blocked the effects of estrogen, suggesting that estrogen protection was mediated via both ERalpha and ERbeta. LPS treatment did not change ERalpha mRNA levels in microglia, astrocytes, and neurons, but it up-regulated ERbeta mRNA levels in microglia and astrocytes. Similarly, increased ERbeta protein levels were detected in LPS-activated microglia. More interesting was that immunocytochemical analysis revealed that ERbeta was localized in the cytoplasm of microglia and in the cell nucleus of astrocytes and neurons. In summary, our results support the notion that estrogen inhibits microglial activation and thus exhibits neuroprotective effects through both ERalpha and ERbeta activation. The cytoplasm location of microglial ERbeta suggests the possible involvement of nonclassical effects of estrogen on microglia. Changes in microglial ERbeta expression levels may modulate such effects of estrogen.
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Affiliation(s)
- Xuan Liu
- Joint Laboratory of Institute of Biomedical Sciences, RuiJin Hospital, Shanghai Second Medical University, Shanghai, People's Republic of China
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466
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Vilhardt F. Microglia: phagocyte and glia cell. Int J Biochem Cell Biol 2005; 37:17-21. [PMID: 15381143 DOI: 10.1016/j.biocel.2004.06.010] [Citation(s) in RCA: 171] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2003] [Revised: 06/09/2004] [Accepted: 06/21/2004] [Indexed: 12/25/2022]
Abstract
Microglia are the resident immune cells of the brain, and are located within the brain parenchyme behind the blood-brain barrier. They originate from mesodermal hemapoietic precursors and are slowly turned over and replenished by proliferation in the adult central nervous system. In the healthy brain resting, ramified microglia function as supportive glia cells, and their activation status is regulated by neurons through soluble mediators and cell-cell contact. However, in response to brain pathology microglia become activated: acquisition of innate immune cell functions render microglia competent to react towards brain injury through tissue repair or induction of immune responses. In certain pathological conditions, however, microglia activation may sustain a chronic inflammation of the brain, leading to neuronal dysfunction and cell death. This might be mediated by the microglial release of extracellular toxic reactive oxygen and nitrogen species. Nevertheless, in the future microglia may potentially be harnessed for therapeutical purposes.
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Affiliation(s)
- Frederik Vilhardt
- Structural Cell Biology Unit, The Panum Institute, Copenhagen University, Building 18.4, Blegdamsvej 3A, 2200 Copenhagen N, Denmark.
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467
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Zhang W, Qin L, Wang T, Wei SJ, Gao HM, Liu J, Wilson B, Liu B, Zhang W, Kim HC, Hong JS. 3-hydroxymorphinan is neurotrophic to dopaminergic neurons and is also neuroprotective against LPS-induced neurotoxicity. FASEB J 2004; 19:395-7. [PMID: 15596482 DOI: 10.1096/fj.04-1586fje] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The purpose of this study was to develop a novel therapy for Parkinson's disease (PD). We recently reported that dextromethorphan (DM), an active ingredient in a variety of widely used anticough remedies, protected dopaminergic neurons in rat primary mesencephalic neuron-glia cultures against lipopolysaccharide (LPS)-mediated degeneration and provided potent protection for dopaminergic neurons in a MPTP mouse model. The underlying mechanism for the protective effect of DM was attributed to its anti-inflammatory activity through inhibition of microglia activation. In an effort to develop more potent compounds for the treatment of PD, we have screened a series of analogs of DM, and 3-hydroxymorphinan (3-HM) emerged as a promising candidate for this purpose. Our study using primary mesencephalic neuron-glia cultures showed that 3-HM provided more potent neuroprotection against LPS-induced dopaminergic neurotoxicity than its parent compound. The higher potency of 3-HM was attributed to its neurotrophic effect in addition to the anti-inflammatory effect shared by both DM and 3-HM. First, we showed that 3-HM exerted potent neuroprotective and neurotrophic effects on dopaminergic neurons in rat primary mesencephalic neuron-glia cultures treated with LPS. The neurotrophic effect of 3-HM was glia-dependent since 3-HM failed to show any protective effect in the neuron-enriched cultures. We subsequently demonstrated that it was the astroglia, not the microglia, that contributed to the neurotrophic effect of 3-HM. This conclusion was based on the reconstitution studies, in which we added different percentages of microglia (10-20%) or astroglia (40-50%) back to the neuron-enriched cultures and found that 3-HM was neurotrophic after the addition of astroglia, but not microglia. Furthermore, 3-HM-treated astroglia-derived conditioned media exerted a significant neurotrophic effect on dopaminergic neurons. It appeared likely that 3-HM caused the release of neurotrophic factor(s) from astroglia, which in turn was responsible for the neurotrophic effect. Second, the anti-inflammatory mechanism was also important for the neuroprotective activity of 3-HM because the more microglia were added back to the neuron-enriched cultures, the more significant neuroprotective effect was observed. The anti-inflammatory mechanism of 3-HM was attributed to its inhibition of LPS-induced production of an array of pro-inflammatory and neurotoxic factors, including nitric oxide (NO), tumor necrosis factor alpha (TNF-alpha), prostaglandin E2 (PGE2) and reactive oxygen species (ROS). In conclusion, this study showed that 3-HM exerted potent neuroprotection by acting on two different targets: a neurotrophic effect mediated by astroglia and an anti-inflammatory effect mediated by the inhibition of microglial activation. 3-HM thus possesses these two important features necessary for an effective neuroprotective agent. In view of the well-documented very low toxicity of DM and its analogs, this report may provide an important new direction for the development of therapeutic interventions for inflammation-related diseases such as PD.
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Affiliation(s)
- Wei Zhang
- Neuropharmacology Section, Laboratory of Pharmacology and Chemistry, National Institute of Environmental Health Sciences/National Institutes of Health, Research Triangle Park, P.O. Box 12233, NC, USA.
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468
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Capuron L, Miller AH. Cytokines and psychopathology: lessons from interferon-alpha. Biol Psychiatry 2004; 56:819-24. [PMID: 15576057 DOI: 10.1016/j.biopsych.2004.02.009] [Citation(s) in RCA: 401] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2003] [Revised: 02/03/2004] [Accepted: 02/10/2004] [Indexed: 01/18/2023]
Abstract
Interferon-alpha is a potent inducer of the cytokine network and is notorious for causing behavioral alterations. Studies on interferon-alpha-treated patients reveal at least two distinct syndromes: 1) a mood/cognitive syndrome that appears late during interferon-alpha therapy is responsive to antidepressants and is associated with activation of neuroendocrine pathways and altered serotonin metabolism; and 2) a neurovegetative syndrome characterized by psychomotor slowing, and fatigue that appears early during interferon-alpha treatment is antidepressant nonresponsive and may be mediated by alterations in basal ganglia dopamine metabolism. Findings from interferon-alpha may provide important clues regarding the pathophysiology and treatment of cytokine-induced behavioral changes in medically ill patients, while also potentially modeling the development of neuropsychiatric symptoms in patients without medical disorders.
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Affiliation(s)
- Lucile Capuron
- Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta, GA 30322, USA
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469
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Peng GS, Li G, Tzeng NS, Chen PS, Chuang DM, Hsu YD, Yang S, Hong JS. Valproate pretreatment protects dopaminergic neurons from LPS-induced neurotoxicity in rat primary midbrain cultures: role of microglia. ACTA ACUST UNITED AC 2004; 134:162-9. [PMID: 15790540 DOI: 10.1016/j.molbrainres.2004.10.021] [Citation(s) in RCA: 130] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2004] [Revised: 09/06/2004] [Accepted: 10/08/2004] [Indexed: 11/29/2022]
Abstract
Parkinson's disease is a neurodegenerative disorder characterized by progressive degeneration of dopaminergic (DA) neurons in the substantia nigra. Accumulating evidence supports the notion that neuroinflammation is involved in the pathogenesis of this disease. Valproate (VPA) has long been used for the treatment of seizures and bipolar mood disorder. In vivo and in vitro studies have demonstrated that VPA has neuroprotective and neurotrophic actions. In this study, using primary neuron-glia cultures from rat midbrain, we demonstrated that VPA is a potent neuroprotective agent against lipopolysaccharide (LPS)-induced neurotoxicity. Results showed that pretreatment with 0.6 mM VPA for 48 h robustly attenuated LPS-induced degeneration of dopaminergic neurons as determined by [(3)H] dopamine uptake and counting of the number of TH-ir neurons. The neuroprotective effect of VPA was concentration-dependent and was mediated, at least in part, through a decrease in levels of pro-inflammatory factors released from activated microglia. Specifically, LPS-induced increase in the release of TNFa, NO, and intracellular reactive oxygen species was markedly reduced in cultures pretreated with VPA. These anti-inflammatory effects of VPA were time and concentration-dependent correlated with a decrease in the number of microglia. Thus, our results demonstrate that protracted VPA pretreatment protects dopaminergic neurons from LPS-induced neurotoxicity through a reduction in levels of released pro-inflammatory factors, and further suggest that these anti-inflammatory effects may be contributed by VPA-induced reduction of microglia cell number. Taken together, our study reinforces the view that VPA may have utility in treating Parkinson's disease.
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Affiliation(s)
- Giia-Sheun Peng
- Department of Neurology, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
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470
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Kim SS, Kong PJ, Kim BS, Sheen DH, Nam SY, Chun W. Inhibitory action of minocycline on lipopolysaccharide-induced release of nitric oxide and prostaglandin E2 in BV2 microglial cells. Arch Pharm Res 2004; 27:314-8. [PMID: 15089037 DOI: 10.1007/bf02980066] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Microglia are the major inflammatory cells in the central nervous system and become activated in response to brain injuries such as ischemia, trauma, and neurodegenerative diseases including Alzheimer's disease (AD). Moreover, activated microglia are known to release a variety of proinflammatory cytokines and oxidants such as nitric oxide (NO). Minocycline is a semisynthetic second-generation tetracycline that exerts anti-inflammatory effects that are completely distinct form its antimicrobial action. In this study, the inhibitory effects of minocycline on NO and prostaglandin E2 (PGE2) release was examined in lipopolysaccharides (LPS)-challenged BV2 murine microglial cells. Further, effects of minocycline on inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expression levels were also determined. The results showed that minocycline significantly inhibited NO and PGE2 production and iNOS and COX-2 expression in BV2 microglial cells. These findings suggest that minocycline should be evaluated as potential therapeutic agent for various pathological conditions due to the excessive activation of microglia.
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Affiliation(s)
- Sung-Soo Kim
- Department of Pharmacology, College of Medicine, Kangwon National University, Chunchon 200-701, Korea
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471
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Ramonet D, Rodríguez MJ, Pugliese M, Mahy N. Putative glucosensing property in rat and human activated microglia. Neurobiol Dis 2004; 17:1-9. [PMID: 15350960 DOI: 10.1016/j.nbd.2003.11.019] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2003] [Revised: 10/30/2003] [Accepted: 11/05/2003] [Indexed: 10/26/2022] Open
Abstract
Microglial cells involved in the pathogenesis of many neurodegenerative diseases acquire the features of cytotoxic and phagocytic cells in response to certain pathogens and inflammatory signals. K(ATP) channels are energy sensors of ATP availability that link the cell's metabolic state to its membrane excitability. In pancreatic beta cells, they promote glucose-dependent insulin secretion, and in neurones, hyperpolarization that protects against hypoxic damage. This study analyses activated microglia in an in vivo rat neurodegenerative model based on acute hippocampal glutamate receptor overactivation and in postmortem samples from patients with Alzheimer's disease. We demonstrate that in activated microglia the K(ATP) channel components SUR-1 or SUR-2 are present together with glucokinase. Our results indicate that, according to glucose availability, these channels may modify microglia membrane potential. The functional relevance of these channels is seen as a new mechanism modulating the effects of external signals on microglia.
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Affiliation(s)
- D Ramonet
- Unitat de Bioquímica, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Facultat de Medicina, Universitat de Barcelona, 08036 Barcelona, Spain
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472
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Rock RB, Gekker G, Hu S, Sheng WS, Cheeran M, Lokensgard JR, Peterson PK. Role of microglia in central nervous system infections. Clin Microbiol Rev 2004; 17:942-64, table of contents. [PMID: 15489356 PMCID: PMC523558 DOI: 10.1128/cmr.17.4.942-964.2004] [Citation(s) in RCA: 500] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The nature of microglia fascinated many prominent researchers in the 19th and early 20th centuries, and in a classic treatise in 1932, Pio del Rio-Hortega formulated a number of concepts regarding the function of these resident macrophages of the brain parenchyma that remain relevant to this day. However, a renaissance of interest in microglia occurred toward the end of the 20th century, fueled by the recognition of their role in neuropathogenesis of infectious agents, such as human immunodeficiency virus type 1, and by what appears to be their participation in other neurodegenerative and neuroinflammatory disorders. During the same period, insights into the physiological and pathological properties of microglia were gained from in vivo and in vitro studies of neurotropic viruses, bacteria, fungi, parasites, and prions, which are reviewed in this article. New concepts that have emerged from these studies include the importance of cytokines and chemokines produced by activated microglia in neurodegenerative and neuroprotective processes and the elegant but astonishingly complex interactions between microglia, astrocytes, lymphocytes, and neurons that underlie these processes. It is proposed that an enhanced understanding of microglia will yield improved therapies of central nervous system infections, since such therapies are, by and large, sorely needed.
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Affiliation(s)
- R Bryan Rock
- Neuroimmunology Laboratory, Minneapolis Medical Research Foundation, and University of Minnesota Medical School, USA
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473
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Arai H, Furuya T, Yasuda T, Miura M, Mizuno Y, Mochizuki H. Neurotoxic effects of lipopolysaccharide on nigral dopaminergic neurons are mediated by microglial activation, interleukin-1beta, and expression of caspase-11 in mice. J Biol Chem 2004; 279:51647-53. [PMID: 15383538 DOI: 10.1074/jbc.m407328200] [Citation(s) in RCA: 97] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The endotoxin lipopolysaccharide (LPS), a component of the Gram-negative bacterial cell wall, selectively induces degeneration of substantia nigral (SN) dopaminergic neurons via activation of microglial cells in rats and mice. Caspase-11 plays a crucial role in LPS-induced septic shock in mice. We examined the mechanism of LPS neurotoxicity on SN dopaminergic neurons in C57BL/6 mice and caspase-11 knockout mice. Mice were stereotaxically injected with LPS into the SN on one side and vehicle into the SN of the other side. Immunohistochemistry, Western blotting analysis, enzyme-linked immunosorbent assay, and reverse transcriptase-PCR were performed to evaluate damage of SN dopaminergic neurons and activation of microglial cells. Intranigral injection of LPS at 1 or 3 microg/microl/site decreased tyrosine hydroxylase-positive neurons and increased microglial cells in the SN compared with the contralateral side injected with vehicle at days 7 and 14 post-injection in C57BL/6 mice. Intranigral injection of LPS at 3 microg/microl/site induced the expression of caspase-11 mRNA in the ventral midbrain at 6, 8, and 12 h post-injection, and the expression of caspase-11-positive cells in the SN at 8 and 12 h post-injection. Moreover, LPS at 3 microg/microl/site increased interleukin-1beta content in the ventral midbrain at 12 and 24 h post-injection. LPS failed to elicit these responses in caspase-11 knockout mice. Our results indicate that the neurotoxic effects of LPS on nigral dopaminergic neurons are mediated by microglial activation, interleukin-1beta, and caspase-11 expression in mice.
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Affiliation(s)
- Hiroyuki Arai
- Research Institute for Diseases of Old Ages, Juntendo University School of Medicine, Tokyo, Japan
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474
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Abstract
Substantial evidence implies that redox imbalance attributable to an overproduction of reactive oxygen species or reactive nitrogen species that overwhelm the protective defense mechanism of cells contributes to all forms of Parkinson's disease. Factors such as dopamine, neuromelanin, and transition metals may, under certain circumstances, contribute to the formation of oxygen species such as H(2)O(2), superoxide radicals, and hydroxyl radicals and react with reactive nitrogen species such as nitric oxide or peroxinitrite. Mitochodrial dysfunction and excitotoxicity may be a cause and a result of oxidative stress. Consequences of this redox imbalance are lipid peroxidation, oxidation of proteins, DNA damage, and interference of reactive oxygen species with signal transduction pathways. These consequences become even more harmful when genetic variations impair the normal degradation of altered proteins. Therefore, therapeutic strategies must aim at reducing free-radical formation and scavenging free-radicals.
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Affiliation(s)
- Daniela Berg
- Institute for Medical Genetics, University of Tuebingen and Hertie Institute for Clinical Brain Research, 72076 Tübingen, Germany.
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475
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Tomás-Camardiel M, Rite I, Herrera AJ, de Pablos RM, Cano J, Machado A, Venero JL. Minocycline reduces the lipopolysaccharide-induced inflammatory reaction, peroxynitrite-mediated nitration of proteins, disruption of the blood-brain barrier, and damage in the nigral dopaminergic system. Neurobiol Dis 2004; 16:190-201. [PMID: 15207276 DOI: 10.1016/j.nbd.2004.01.010] [Citation(s) in RCA: 152] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2003] [Revised: 01/08/2004] [Accepted: 01/14/2004] [Indexed: 12/14/2022] Open
Abstract
We have evaluated the potential neuroprotectant activity of minocycline in an animal model of Parkinson's disease induced by intranigral injection of lipopolysaccharide. Minocycline treatment was very effective in protecting number of nigral dopaminergic neurons and loss of reactive astrocytes at 7 days postlesion. Evaluation of microglia revealed that minocycline treatment highly prevented the lipopolysaccharide-induced activation of reactive microglia as visualized by OX-42 and OX-6 immunohistochemistry. Short-term RT-PCR analysis demonstrated that minocycline partially prevented the lipopolysaccharide-induced increases of mRNA levels for interleukin-1alpha and tumor necrosis factor-alpha. In addition, lipopolysaccharide highly induced protein nitration as seen by 3-nitrotyrosine immunoreactivity in the ventral mesencephalon. Minocycline treatment strongly diminished the extent of 3-nitrotyrosine immunoreactivity. We also found a direct correlation between location of IgG immunoreactivity-a marker of blood-brain barrier disruption-and neurodegenerative processes including death of nigral dopaminergic cells and reactive astrocytes. There was also a precise spatial correlation between disruption of blood-brain barrier and 3-nitrotyrosine immunoreactivity. We discuss potential involvement of lipopolysaccharide-induced formation of peroxynitrites and cytokines in the pathological events in substantia nigra in response to inflammation. If inflammation is proved to be involved in the ethiopathology of Parkinson's disease, our data support the use of minocycline in parkinsonian patients.
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Affiliation(s)
- Mayka Tomás-Camardiel
- Departamento de Bioquímica, Bromatología, Toxicología y Medicina Legal Facultad de Farmacia, Universidad de Sevilla, E-41012-Seville, Spain
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476
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Maragos WF, Young KL, Altman CS, Pocernich CB, Drake J, Butterfield DA, Seif I, Holschneider DP, Chen K, Shih JC. Striatal damage and oxidative stress induced by the mitochondrial toxin malonate are reduced in clorgyline-treated rats and MAO-A deficient mice. Neurochem Res 2004; 29:741-6. [PMID: 15098936 DOI: 10.1023/b:nere.0000018845.82808.45] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Intrastriatal administration of the succinate dehydrogenase (SDH) inhibitor malonate produces neuronal injury by a "secondary excitotoxic" mechanism involving the generation of reactive oxygen species (ROS). Recent evidence indicates dopamine may contribute to malonate-induced striatal neurodegeneration; infusion of malonate causes a pronounced increase in extracellular dopamine and dopamine deafferentation attenuates malonate toxicity. Inhibition of the catabolic enzyme monoamine oxidase (MAO) also attenuates striatal lesions induced by malonate. In addition to forming 3,4-dihydroxyphenylacetic acid, metabolism of dopamine by MAO generates H2O2, suggesting that dopamine metabolism may be a source of ROS in malonate toxicity. There are two isoforms of MAO, MAO-A and MAO-B. In this study, we have investigated the role of each isozyme in malonate-induced striatal injury using both pharmacological and genetic approaches. In rats treated with either of the specific MAO-A or -B inhibitors, clorgyline or deprenyl, respectively, malonate lesion volumes were reduced by 30% compared to controls. In knock-out mice lacking the MAO-A isoform, malonate-induced lesions were reduced by 50% and protein carbonyls, an index ROS formation, were reduced by 11%, compared to wild-type animals. In contrast, mice deficient in MAO-B showed highly variable susceptibility to malonate toxicity precluding us from determining the precise role of MAO-B in this form of brain damage. These findings indicate that normal levels of MAO-A participate in expression of malonate toxicity by a mechanism involving oxidative stress.
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477
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Sánchez-Pernaute R, Ferree A, Cooper O, Yu M, Brownell AL, Isacson O. Selective COX-2 inhibition prevents progressive dopamine neuron degeneration in a rat model of Parkinson's disease. J Neuroinflammation 2004; 1:6. [PMID: 15285796 PMCID: PMC483059 DOI: 10.1186/1742-2094-1-6] [Citation(s) in RCA: 153] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2004] [Accepted: 05/17/2004] [Indexed: 11/22/2022] Open
Abstract
Several lines of evidence point to a significant role of neuroinflammation in Parkinson's disease (PD) and other neurodegenerative disorders. In the present study we examined the protective effect of celecoxib, a selective inhibitor of the inducible form of cyclooxygenase (COX-2), on dopamine (DA) cell loss in a rat model of PD. We used the intrastriatal administration of 6-hydroxydopamine (6-OHDA) that induces a retrograde neuronal damage and death, which progresses over weeks. Animals were randomized to receive celecoxib (20 mg/kg/day) or vehicle starting 1 hour before the intrastriatal administration of 6-OHDA. Evaluation was performed in vivo using micro PET and selective radiotracers for DA terminals and microglia. Post mortem analysis included stereological quantification of tyrosine hydroxylase, astrocytes and microglia. 12 days after the 6-OHDA lesion there were no differences in DA cell or fiber loss between groups, although the microglial cell density and activation was markedly reduced in animals receiving celecoxib (p < 0.01). COX-2 inhibition did not reduce the typical astroglial response in the striatum at any stage. Between 12 and 21 days, there was a significant progression of DA cell loss in the vehicle group (from 40 to 65%) that was prevented by celecoxib. Therefore, inhibition of COX-2 by celecoxib appears to be able, either directly or through inhibition of microglia activation to prevent or slow down DA cell degeneration.
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Affiliation(s)
- Rosario Sánchez-Pernaute
- McLean Hospital/Harvard University Udall Parkinson's Disease Research Center of Excellence, Belmont, Massachusetts, USA
- Neuroregeneration Laboratories, McLean Hospital, Belmont, Massachusetts, USA
| | - Andrew Ferree
- McLean Hospital/Harvard University Udall Parkinson's Disease Research Center of Excellence, Belmont, Massachusetts, USA
- Neuroregeneration Laboratories, McLean Hospital, Belmont, Massachusetts, USA
| | - Oliver Cooper
- McLean Hospital/Harvard University Udall Parkinson's Disease Research Center of Excellence, Belmont, Massachusetts, USA
- Neuroregeneration Laboratories, McLean Hospital, Belmont, Massachusetts, USA
| | - Meixiang Yu
- McLean Hospital/Harvard University Udall Parkinson's Disease Research Center of Excellence, Belmont, Massachusetts, USA
- Department of Radiology, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Anna-Liisa Brownell
- McLean Hospital/Harvard University Udall Parkinson's Disease Research Center of Excellence, Belmont, Massachusetts, USA
- Department of Radiology, Massachusetts General Hospital, Boston, Massachusetts, USA
| | - Ole Isacson
- McLean Hospital/Harvard University Udall Parkinson's Disease Research Center of Excellence, Belmont, Massachusetts, USA
- Neuroregeneration Laboratories, McLean Hospital, Belmont, Massachusetts, USA
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478
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LaVoie MJ, Card JP, Hastings TG. Microglial activation precedes dopamine terminal pathology in methamphetamine-induced neurotoxicity. Exp Neurol 2004; 187:47-57. [PMID: 15081587 DOI: 10.1016/j.expneurol.2004.01.010] [Citation(s) in RCA: 164] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2003] [Revised: 12/22/2003] [Accepted: 01/13/2004] [Indexed: 11/20/2022]
Abstract
Previous studies have demonstrated methamphetamine (METH)-induced toxicity to dopaminergic and serotonergic axons in rat striatum. Although several studies have identified the nature of reactive astrogliosis in this lesion model, the response of microglia has not been examined in detail. In this investigation, we characterized the temporal relationship of reactive microgliosis to neuropathological alterations of dopaminergic axons in striatum following exposure to methamphetamine. Adult male Sprague-Dawley rats were administered a neurotoxic regimen of methamphetamine and survived 12 h, or 1, 2, 4, and 6 days after treatment. Immunohistochemical methods were used to evaluate reactive changes in microglia throughout the brain of methamphetamine-treated rats, with a particular focus upon striatum. Pronounced morphological changes, indicative of reactive microgliosis, were evident in the brains of all methamphetamine-treated animals and were absent in saline-treated control animals. These included hyperplastic changes in cell morphology that substantially increased the size and staining intensity of reactive microglia. Quantitative analysis of reactive microglial changes in striatum demonstrated that these changes were most robust within the ventrolateral region and were maximal 2 days after methamphetamine administration. Analysis of tissue also revealed that microglial activation preceded the appearance of pathological changes in striatal dopamine fibers. Reactive microgliosis was also observed in extra-striatal regions (somatosensory and piriform cortices, and periaqueductal gray). These data demonstrate a consistent, robust, and selective activation of microglia in response to methamphetamine administration that, at least in striatum, precedes the appearance of morphological indicators of axon pathology. These observations raise the possibility that activated microglia may contribute to methamphetamine-induced neurotoxicity.
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Affiliation(s)
- Matthew J LaVoie
- Department of Neuroscience, University of Pittsburgh, Pittsburgh, PA 15213, USA
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479
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Furuya T, Hayakawa H, Yamada M, Yoshimi K, Hisahara S, Miura M, Mizuno Y, Mochizuki H. Caspase-11 mediates inflammatory dopaminergic cell death in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine mouse model of Parkinson's disease. J Neurosci 2004; 24:1865-72. [PMID: 14985426 PMCID: PMC6730410 DOI: 10.1523/jneurosci.3309-03.2004] [Citation(s) in RCA: 114] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The present study was designed to elucidate the inflammatory and apoptotic mechanisms of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced neurotoxicity in a model of Parkinson's disease. Our results showed that mutant mice lacking the caspase-11 gene were significantly more resistant to the effects of acute treatment with MPTP than their wild-type mice. Thus, the neurotoxicity of MPTP seems to be mediated by the induction of both mitochondrial dysfunction and free radical generation. Previously, we showed that overexpression of the Apaf-1 dominant-negative inhibitor inhibited the mitochondrial apoptotic cascade in chronic MPTP treatment but not in acute MPTP treatment. The present results indicate that MPTP neurotoxicity may be mediated via activation of the caspase-11 cascade and inflammatory cascade, as well as the mitochondrial apoptotic cascade.
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Affiliation(s)
- Tsuyoshi Furuya
- Department of Neurology, Juntendo University School of Medicine, Bunkyo-ku, Tokyo 113-8421, Japan
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480
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Natarajan C, Sriram S, Muthian G, Bright JJ. Signaling through JAK2-STAT5 pathway is essential for IL-3-induced activation of microglia. Glia 2004; 45:188-96. [PMID: 14730712 DOI: 10.1002/glia.10316] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Microglia, the resident macrophage of the brain, mediates immune and inflammatory responses in the central nervous system (CNS). Activation of microglia and secretion of inflammatory cytokines associate with the pathogenesis of CNS diseases, including multiple sclerosis (MS), Alzheimer's disease (AD), Parkinson's disease, prion disease, and AIDS dementia. Microbial pathogens, cytokines, chemokines, and costimulatory molecules are potent inducers of microglial activation in the CNS. Signaling through its receptor, IL-3 induces the activation of JAK-STAT and MAP kinase pathways in microglial cells. In this study, we found that in vitro treatment of EOC-20 microglial cells with tyrphostin AG490 blocked IL-3-induced tyrosine phosphorylation of JAK2, STAT5A, and STAT5B signaling proteins. Stable transfection of EOC-20 cells with a dominant negative JAK2 mutant also blocked IL-3-induced tyrosine phosphorylation of JAK2, STAT5A, and STAT5B in microglia. The blockade of JAK2-STAT5 pathway resulted in a decrease in IL-3-induced proliferation and expression of CD40 and major histocompatibility complex class II molecules in microglia. These findings highlight the fact that JAK2-STAT5 signaling pathway plays a critical role in mediating IL-3-induced activation of microglia.
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Affiliation(s)
- Chandramohan Natarajan
- Department of Neurology and Pharmacology, Vanderbilt University Medical Center, 1222F VSRH, 2201 Capers Avenue, Nashville, TN 37212, USA.
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481
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Ringheim GE, Conant K. Neurodegenerative disease and the neuroimmune axis (Alzheimer's and Parkinson's disease, and viral infections). J Neuroimmunol 2004; 147:43-9. [PMID: 14741426 DOI: 10.1016/j.jneuroim.2003.10.013] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The appearance of activated immune cells and the accumulation of inflammation-associated proteins are common phenomena associated with neurodegenerative diseases. These inflammatory components of central nervous system (CNS) diseases have most often been described in the context of an immune response to damage and cell loss already occurring in the affected brain area. There has, however, been a renewed interest in how the neuroimmune axis might itself be involved in the etiology of these neurodegenerative diseases, particularly in cases involving slow, chronic, progressive neuropathology. This review addresses immune activation in Alzheimer's, Parkinson's, and brain viral infections that may be causative of, rather than responsive to, the observed neuronal loss in these pathologies.
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Affiliation(s)
- Garth E Ringheim
- Immunology Platform, Aventis Pharmaceuticals, Inc., Route 202-206, Mail Stop G303A, Bridgewater, NJ 08807-0800, USA.
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482
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Dehmer T, Heneka MT, Sastre M, Dichgans J, Schulz JB. Protection by pioglitazone in the MPTP model of Parkinson's disease correlates with I kappa B alpha induction and block of NF kappa B and iNOS activation. J Neurochem 2004; 88:494-501. [PMID: 14690537 DOI: 10.1046/j.1471-4159.2003.02210.x] [Citation(s) in RCA: 290] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Inflammation has been implicated in the pathogenesis of Parkinson's disease (PD). In the chronic 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) model of PD, inducible NO synthase (iNOS) derived nitric oxide (NO) is an important mediator of dopaminergic cell death. Ligands of the peroxisome proliferator-activated receptor (PPAR) exert anti-inflammatory effects. We here investigated whether pioglitazone, a PPARgamma agonist, protected mice from MPTP-induced dopaminergic cell loss, glial activation, and loss of catecholamines in the striatum. As shown by western blot, PPARgamma was expressed in the striatum and the substantia nigra of vehicle- and MPTP-treated mice. Oral administration of 20 mg/(kg day) of pioglitazone protected tyrosine hydroxylase (TH)-positive substantia nigra neurons from death induced by 5 x 30 mg/kg MPTP. However, the decrease of dopamine in the striatum was only partially prevented. In mice treated with pioglitazone, there were a reduced activation of microglia, reduced induction of iNOS-positive cells and less glial fibrillary acidic protein positive cells in both striatum and substantia nigra pars compacta. In addition, treatment with pioglitazone almost completely blocked staining of TH-positive neurons for nitrotyrosine, a marker of NO-mediated cell damage. Because an increase in inhibitory protein-kappa-Balpha (IkappaBalpha) expression and inhibition of translocation of the nuclear factor kappaB (NFkappaB) subunit p65 to the nucleus in dopaminergic neurons, glial cells and astrocytes correlated with the protective effects of pioglitazone, our results suggest that pioglitazone sequentially acts through PPARgamma activation, IkappaBalpha induction, block of NFkappaB activation, iNOS induction and NO-mediated toxicity. In conclusion, treatment with pioglitazone may offer a treatment opportunity in PD to slow the progression of disease that is mediated by inflammation.
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Affiliation(s)
- Thomas Dehmer
- Neurodegeneration Laboratory, Center of Neurology and Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
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483
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Wang T, Liu B, Qin L, Wilson B, Hong JS. Protective effect of the SOD/catalase mimetic MnTMPyP on inflammation-mediated dopaminergic neurodegeneration in mesencephalic neuronal-glial cultures. J Neuroimmunol 2004; 147:68-72. [PMID: 14741430 DOI: 10.1016/j.jneuroim.2003.10.040] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Reactive oxygen species (ROS) produced by activated microglia are deleterious to neurons. In this study, we studied the effect of Mn(III)tetrakis(1-methyl-4-pyridyl)porphyrin (MnTMPyP), a superoxide dismutase/catalase mimetic, on the lipopolysaccharide (LPS)-induced degeneration of dopaminergic neurons in rat mesencephalic neuroglia cultures. MnTMPyP exhibited a significantly protective effect against LPS (5 ng/ml)-induced neurotoxicity as determined by [3H]dopamine uptake and immunocytochemical analysis. MnTMPyP significantly attenuated LPS-induced production of superoxide free radical and prostaglandin E(2) (PGE(2)) in microglia. These results indicate that MnTMPyP may potentially be used for the treatment of inflammation-related degenerative neurological disorders.
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Affiliation(s)
- Tongguang Wang
- Laboratory of Pharmacology and Chemistry, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
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484
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Sánchez-Alavez M, Gombart LM, Huitrón-Reséndiz S, Carr JR, Wills DN, Berg G, Campbell IL, Gauvin DV, Henriksen SJ, Criado JR. Physiological and behavioral effects of methamphetamine in a mouse model of endotoxemia: a preliminary study. Pharmacol Biochem Behav 2004; 77:365-70. [PMID: 14751466 DOI: 10.1016/j.pbb.2003.11.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We investigated the effects of methamphetamine (METH) on core body temperature (Tb) and motor activity (MA) with or without exposure to a peripheral immune challenge. Mice were exposed to an escalating METH treatment and then to a METH treatment known to cause neurotoxicity (binge METH treatment). This was followed by a challenge with lipopolysaccharide (LPS). Three days later, METH and saline-treated control groups were challenged with an acute test dose of METH (METH test). Animals exposed to the escalating METH treatment exhibited a significant increase in Tb only after the initial exposure to METH (Day 1) and following the METH test (Day 7). The hyperthermic effect produced by the METH test (Day 7) was reduced in mice previously exposed to combined exposure to binge METH and LPS treatments. The escalating METH treatment produced MA sensitization to the METH test. Animals treated with the binge METH, LPS injection or both treatments combined prevented MA sensitization to the METH test. These findings suggest that induction of peripheral endotoxemia in animals with a history of METH reduced the hyperthermic response to a subsequent challenge with METH.
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Affiliation(s)
- Manuel Sánchez-Alavez
- Department of Neuropharmacology, The Scripps Research Institute, CVN-13, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
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485
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Milatovic D, Zaja-Milatovic S, Montine KS, Horner PJ, Montine TJ. Pharmacologic suppression of neuronal oxidative damage and dendritic degeneration following direct activation of glial innate immunity in mouse cerebrum. J Neurochem 2004; 87:1518-26. [PMID: 14713307 DOI: 10.1046/j.1471-4159.2003.02120.x] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Activation of glial innate immunity is widely proposed to contribute to a number of degenerative and destructive diseases of brain. However, the precise role of activated innate immunity has been difficult to define in vivo because of multiple simultaneous pathogenic processes and responses to injury that confound interpretation of results from complex models of disease. Here, we used the model of intracerebroventricular (ICV) injection of lipopolysaccharide (LPS) to test the hypothesis that directly activated glial innate immunity leads to neurodegeneration in cerebrum and to establish the molecular determinants of and neuroprotectants from such innate immunity-mediated neuronal damage. Our results showed that ICV LPS induced delayed, reversible oxidative damage to cerebral neuronal membranes as measured by F4-neuroprostanes that was coincident with degeneration of the hippocampal pyramidal neuron dendritic system, but not neuron death, in adult mice. Both neuronal oxidative damage and dendritic degeneration were NF-kappaB and iNOS dependent and were completely suppressed by ibuprofen and alpha-tocopherol, but not naproxen or gamma-tocopherol. These results prove that activation of glial innate immunity can lead to neurodegeneration independent of other pathologic processes, closely associate oxidative damage to neuronal membranes with degeneration of the dendritic system, and provide a possible explanation for the varying efficacy of neuroprotectants that have been suggested in observational studies of dementia.
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Affiliation(s)
- Dejan Milatovic
- Department of Pathology, University of Washington, Harborview Medical Center, Seattle, Washington 98104, USA
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486
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Vaziri ND, Lee YS, Lin CY, Lin VW, Sindhu RK. NAD(P)H oxidase, superoxide dismutase, catalase, glutathione peroxidase and nitric oxide synthase expression in subacute spinal cord injury. Brain Res 2004; 995:76-83. [PMID: 14644473 DOI: 10.1016/j.brainres.2003.09.056] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Primary trauma to the spinal cord triggers a cascade of cellular and molecular events that promote continued tissue damage and expansion of the lesion for extended periods following the initial injury. Oxidative and nitrosative stresses play an important role in progression of spinal cord injury (SCI). In an attempt to explore the biochemical origin of oxidative/nitrosative stress associated with secondary SCI, we studied expression of the superoxide (O2*-)-generating enzyme, NAD(P)H oxidase, antioxidant enzymes [superoxide dismutase (CuZn SOD, Mn SOD), catalase, glutathione peroxidase (GPX)], nitric oxide synthases (NOS) and a byproduct of NO-O2*- interaction (nitrotyrosine) in the spinal cord tissues of rats 16 h and 14 days after surgical resections of a 5-mm segment of the cord below T8 or sham-operation. Immunodetectable NAD(P)H oxidase subunits (gp91phox and P67phox), Mn SOD, inducible NOS (iNOS), endothelial NOS (eNOS), and nitrotyrosine were elevated in the transected cords on day 1 and day 14. Neuronal NOS (nNOS) was unchanged on day 1 and significantly depressed on day 14. GPX was unchanged on day 1 and significantly elevated on day 14. Catalase was unchanged in the cord tissue surrounding the transection site at both points. Thus, concurrent upregulations of NAD(P)H oxidase, eNOS and iNOS (but not nNOS), work in concert to maintain oxidative and nitrosative stress in the injured cord tissue.
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Affiliation(s)
- Nosratola D Vaziri
- Division of Nephrology and Hypertension, University of California at Irvine Medical Center, 101 The City Drive, Building 53, Room 125, Rt. 81, Orange, CA 92868, USA.
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487
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Li R, Huang YG, Fang D, Le WD. (?)-Epigallocatechin gallate inhibits lipopolysaccharide-induced microglial activation and protects against inflammation-mediated dopaminergic neuronal injury. J Neurosci Res 2004; 78:723-31. [PMID: 15478178 DOI: 10.1002/jnr.20315] [Citation(s) in RCA: 147] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Microglial activation is believed to play a pivotal role in the selective neuronal injury associated with several neurodegenerative disorders, including Parkinson's disease (PD) and Alzheimer's disease. We provide evidence that (-)-epigallocatechin gallate (EGCG), a major monomer of green tea polyphenols, potently inhibits lipopolysaccharide (LPS)-activated microglial secretion of nitric oxide (NO) and tumor necrosis factor-alpha (TNF-alpha) through the down-regulation of inducible NO synthase and TNF-alpha expression. In addition, EGCG exerted significant protection against microglial activation-induced neuronal injury both in the human dopaminergic cell line SH-SY5Y and in primary rat mesencephalic cultures. Our study demonstrates that EGCG is a potent inhibitor of microglial activation and thus is a useful candidate for a therapeutic approach to alleviating microglia-mediated dopaminergic neuronal injury in PD.
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Affiliation(s)
- Rui Li
- Health Science Center, Shanghai Institute for Biological Science, Chinese Academy of Science, Shanghai Second Medical University, Shanghai, Peoples Republic of China
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488
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Qin L, Liu Y, Wang T, Wei SJ, Block ML, Wilson B, Liu B, Hong JS. NADPH oxidase mediates lipopolysaccharide-induced neurotoxicity and proinflammatory gene expression in activated microglia. J Biol Chem 2003; 279:1415-21. [PMID: 14578353 DOI: 10.1074/jbc.m307657200] [Citation(s) in RCA: 467] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Parkinson's disease is characterized by the progressive degeneration of dopaminergic neurons in the substantia nigra. We have previously reported that lipopolysaccharide (LPS)-induced degeneration of dopaminergic neurons is mediated by the release of proinflammatory factors from activated microglia. Here, we report the pivotal role of NADPH oxidase in inflammation-mediated neurotoxicity, where the LPS-induced loss of nigral dopaminergic neurons in vivo was significantly less pronounced in NADPH oxidase-deficient (PHOX-/-) mice when compared with control (PHOX+/+) mice. Dopaminergic neurons in primary mensencephalic neuron-glia cultures from PHOX+/+ mice were significantly more sensitive to LPS-induced neurotoxicity in vitro when compared with PHOX-/- mice. Further, PHOX+/+ neuron-glia cultures chemically depleted of microglia failed to show dopaminergic neurotoxicity with the addition of LPS. Neuron-enriched cultures from both PHOX+/+ mice and PHOX-/- mice also failed to show any direct LPS-induced dopaminergic neurotoxicity. However, the addition of PHOX+/+ microglia to neuron-enriched cultures from either strain resulted in reinstatement of LPS-induced dopaminergic neurotoxicity, supporting the role of microglia as the primary source of NADPH oxidase-generated insult and neurotoxicity. Immunostaining for F4/80 in mensencephalic neuron-glia cultures revealed that PHOX-/- microglia failed to show activated morphology at 10 h, suggesting an important role of reactive oxygen species (ROS) generated from NADPH oxidase in the early activation of microglia. LPS also failed to elicit extracellular superoxide and produced low levels of intracellular ROS in microglia-enriched cultures from PHOX-/- mice. Gene expression and release of tumor necrosis factor alpha was much lower in PHOX-/- mice than in control PHOX+/+ mice. Together, these results demonstrate the dual neurotoxic functions of microglial NADPH oxidase: 1) the production of extracellular ROS that is toxic to dopamine neurons and 2) the amplification of proinflammatory gene expression and associated neurotoxicity.
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Affiliation(s)
- Liya Qin
- Neuropharmacology Section, Laboratory of Pharmacology and Chemistry, NIEHS, NIH, Research Triangle Park, NC 27709, USA
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489
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Abstract
Neurodegenerative diseases are morphologically featured by progressive cell loss in specific vulnerable neuronal populations of the central nervous system, often associated with cytoskeletal protein aggregates forming intracytoplasmic and/or intranuclear inclusions in neurons and/or glial cells. Most neurodegenerative disorders are now classified either according to the hitherto known genetic mechanisms or to the major components of their cellular protein inclusions. The major basic processes inducing neurodegeneration are considered multifactorial ones caused by genetic, environmental, and endogenous factors. They include abnormal protein dynamics with defective protein degradation and aggregation, many of them related to the ubiquitin-proteasomal system, oxidative stress and free radical formation, impaired bioenergetics and mitochondrial dysfunctions, and "neuroinflammatory" processes. These mechanisms that are usually interrelated in complex vitious circles finally leading to programmed cell death cascades are briefly discussed with reference to their pathogenetic role in many, albeit diverse neurodegenerative diseases, like Alzheimer disease, synucleinopathies, tauopathies, and polyglutamine disorders. The impact of protein inclusions on cell dysfunction, activation or prevention of cell death cascades are discussed, but the molecular basis for the underlying disease mechanisms remains to be elucidated.
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Affiliation(s)
- K A Jellinger
- Institute of Clinical Neurobiology, Vienna, Austria.
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490
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Gao HM, Liu B, Zhang W, Hong JS. Critical role of microglial NADPH oxidase-derived free radicals in the in vitro MPTP model of Parkinson's disease. FASEB J 2003; 17:1954-6. [PMID: 12897068 DOI: 10.1096/fj.03-0109fje] [Citation(s) in RCA: 222] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) damages dopaminergic neurons as seen in Parkinson's disease. Although increasing evidence suggests an involvement of glia in MPTP neurotoxicity, the nature of this involvement remains unclear. Exploiting the advantage of cell culture systems, we demonstrated that microglia, but not astroglia, significantly enhanced the progression of MPTP-induced dopaminergic neurodegeneration. Characterization of the temporal relationship between neurodegeneration and microglial activation demonstrates that reactive microgliosis resulting from MPTP-initiated neuronal injury, but not direct activation, underlies the microglia-enhanced MPTP neurotoxicity. Mechanistically, through the release of NADPH oxidase-derived reactive oxygen species, microglia contribute to the progressive neuronal damage. Among the factors measured, the production of extracellular superoxide was the most prominent. NADPH oxidase inhibitor, apocynin, attenuated MPTP-induced dopaminergic neurodegeneration only in the presence of glia. More importantly, dopaminergic neurons from mice lacking NADPH oxidase, a key enzyme for superoxide production in immune cells, are significantly more resistant to MPTP neurotoxicity than those from wild-type controls, and microglia dictate the resistance. This study demonstrates that reactive microgliosis triggered by MPTP-induced neuronal injury and NADPH oxidase-mediated superoxide production in microglia constitute an integral component of MPTP neurotoxicity. This study also suggests that NADPH oxidase may be a promising target for therapeutic interventions in Parkinson's disease.
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Affiliation(s)
- Hui-Ming Gao
- Neuropharmacology Section, Laboratory of Pharmacology and Chemistry, National Institute of Environmental Health Sciences/National Institutes of Health, Research Triangle Park, North Carolina, USA
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491
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Gao HM, Liu B, Zhang W, Hong JS. Synergistic dopaminergic neurotoxicity of MPTP and inflammogen lipopolysaccharide: relevance to the etiology of Parkinson's disease. FASEB J 2003; 17:1957-9. [PMID: 12923073 DOI: 10.1096/fj.03-0203fje] [Citation(s) in RCA: 128] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Parkinson's disease (PD) is a profound movement disorder resulting from progressive degeneration of the nigrostriatal dopaminergic pathway. Although its etiology remains unknown, increasing evidence suggests the involvement of multiple factors such as environmental toxins and genetic susceptibilities in the pathogenesis of PD. In this study using mesencephalic neuron-glia cultures as an in vitro PD model, we demonstrated that the neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP, 0.1-0.5 microM) and an inflammogen lipopolysaccharide (LPS, 0.5 ng/ml) synergistically induced a progressive and selective degeneration of dopaminergic neurons. The synergistic neurotoxicity was observed when both agents were applied either simultaneously or in tandem. The synergistic neurotoxicity was more prominent when lower doses of both agents were applied for a longer period of time. Mechanistically, microglial NADPH oxidase-mediated generation of reactive oxygen species played a pivotal role in the synergistic neurotoxicity: MPTP and LPS synergistically stimulated the NADPH oxidase-mediated release of superoxide free radical; pharmacological inhibition and genetic inactivation of NADPH oxidase prevented superoxide production and the synergistic neurotoxicity. Additionally, inhibition of nitric oxide synthase afforded significant neuroprotection, suggesting the involvement of nitric oxide in the synergistic neurotoxicity. This study lends strong support for a multifactorial etiology of PD and provides clues for therapeutic interventions.
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Affiliation(s)
- Hui-Ming Gao
- Neuropharmacology Section, Laboratory of Pharmacology and Chemistry, National Institute of Environmental Health Sciences/National Institutes of Health, Research Triangle Park, North Carolina 27709, USA.
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492
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Huh Y, Jung JW, Park C, Ryu JR, Shin CY, Kim WK, Ryu JH. Microglial activation and tyrosine hydroxylase immunoreactivity in the substantia nigral region following transient focal ischemia in rats. Neurosci Lett 2003; 349:63-7. [PMID: 12946587 DOI: 10.1016/s0304-3940(03)00743-2] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The temporal profiles of the changes of dopaminergic cells and microglial activation induced by transient cerebral ischemia were investigated in the substantia nigra pars compacta (SNc) located outside ischemic areas of rat brain. Transient cerebral ischemia was induced by intraluminal occlusion of the right middle cerebral artery for 2 h and reperfusion was continued for 1, 2, 3, 4, 7, 10, 14, 28, 60, and 120 days. Dopaminergic cells immunostained with tyrosine hydroxylase (TH)-antibody in the ipsilateral SNc were significantly decreased at 7 days post-ischemia compared with those in the contralateral side (P<0.05). However, at 60 and 120 days, there were no significant differences between ipsilateral and contralateral side of the SNc. Unlike the TH immunoreactivity, activated microglial cells immunostained with OX-42 antibody were significantly increased at 2 and 3 days and then decreased gradually until 10 days post-ischemia. Activated microglial cells were increased at 2 weeks post-ischemia, and this pattern remained until 60 days. These results suggest that the transient changes of TH-immunoreactive cells in the SNc caused by transient focal ischemia are correlated with a biphasic microglial cell activation response.
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Affiliation(s)
- Youngbuhm Huh
- Department of Anatomy, College of Medicine, College of Pharmacy, Kyung Hee University, 1 Hoeki-dong, Dongdeamoon-ku, Seoul 130-701, South Korea
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493
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Shibata H, Katsuki H, Nishiwaki M, Kume T, Kaneko S, Akaike A. Lipopolysaccharide-induced dopaminergic cell death in rat midbrain slice cultures: role of inducible nitric oxide synthase and protection by indomethacin. J Neurochem 2003; 86:1201-12. [PMID: 12911628 DOI: 10.1046/j.1471-4159.2003.01929.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Glial cell activation associated with inflammatory reaction may contribute to pathogenic processes of neurodegenerative disorders, through production of several cytotoxic molecules. We investigated the consequences of glial activation by interferon-gamma (IFN-gamma)/lipopolysaccharide (LPS) in rat midbrain slice cultures. Application of IFN-gamma followed by LPS caused dopaminergic cell death and accompanying increases in nitrite production and lactate dehydrogenase release. Aminoguanidine, an inhibitor of inducible nitric oxide synthase (iNOS), or SB203580, an inhibitor of p38 mitogen-activated protein kinase, prevented dopaminergic cell loss as well as nitrite production. SB203580 also suppressed expression of iNOS and cyclooxygenase-2 (COX-2) induced by IFN-gamma/LPS. A COX inhibitor indomethacin protected dopaminergic neurons from IFN-gamma/LPS-induced injury, whereas selective COX-2 inhibitors such as NS-398 and nimesulide did not. Notably, indomethacin was able to attenuate neurotoxicity of a nitric oxide (NO) donor. Neutralizing antibodies against tumour necrosis factor-alpha and interleukin-1beta did not inhibit dopaminergic cell death caused by IFN-gamma/LPS, although combined application of these antibodies blocked lactate dehydrogenase release and decrease in the number of non-dopaminergic neurons. These results indicate that iNOS-derived NO plays a crucial role in IFN-gamma/LPS-induced dopaminergic cell death, and that indomethacin exerts protective effect by mechanisms probably related to NO neurotoxicity rather than through COX inhibition.
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Affiliation(s)
- Haruki Shibata
- Department of Pharmacology, Graduate School of Pharmaceutical Sciences, Kyoto University, 46-29 Yoshida-shimoadachi-cho, Sakyo-ku, Kyoto 606-8501, Japan
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494
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Abstract
Increasing evidence has suggested an important role for environmental toxins such as pesticides in the pathogenesis of Parkinson's disease (PD). Chronic exposure to rotenone, a common herbicide, reproduces features of Parkinsonism in rats. Mechanistically, rotenone-induced dopaminergic neurodegeneration has been associated with both its inhibition of neuronal mitochondrial complex I and the enhancement of activated microglia. Our previous studies with NADPH oxidase inhibitors, diphenylene iodonium and apocynin, suggested that NADPH oxidase-derived superoxide might be a major factor in mediating the microglia-enhanced rotenone neurotoxicity. However, because of the relatively low specificity of these inhibitors, the exact source of superoxide induced by rotenone remains to be further determined. In this study, using primary mesencephalic cultures from NADPH oxidase--null (gp91phox-/-) or wild-type (gp91phox+/+) mice, we demonstrated a critical role for microglial NADPH oxidase in mediating microglia-enhanced rotenone neurotoxicity. In neuron--glia cultures, dopaminergic neurons from gp91phox-/- mice were more resistant to rotenone neurotoxicity than those from gp91phox+/+ mice. However, in neuron-enriched cultures, the neurotoxicity of rotenone was not different between the two types of mice. More importantly, the addition of microglia prepared from gp91phox+/+ mice but not from gp91phox-/- mice to neuron-enriched cultures markedly increased rotenone-induced degeneration of dopaminergic neurons. Furthermore, apocynin attenuated rotenone neurotoxicity only in the presence of microglia from gp91phox+/+ mice. These results indicated that the greatly enhanced neurotoxicity of rotenone was attributed to the release of NADPH oxidase-derived superoxide from activated microglia. This study also suggested that microglial NADPH oxidase may be a promising target for PD treatment.
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495
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Choi HB, Hong SH, Ryu JK, Kim SU, McLarnon JG. Differential activation of subtype purinergic receptors modulates Ca(2+) mobilization and COX-2 in human microglia. Glia 2003; 43:95-103. [PMID: 12838502 DOI: 10.1002/glia.10239] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
We have studied modulation of purinergic receptors (P(2Y) and P(2X) subtypes) on changes in intracellular Ca(2+) [Ca(2+)](i) and expression and production of COX-2 in human microglia. Measurements using Ca(2+)-sensitive spectrofluorometry showed adenosine triphosphate (ATP) to cause rapid transient increases in [Ca(2+)](i). Application of ATP plus the P(2X) antagonist, pyridoxal-phosphate-6-azophenyl-2',4'-disulfonic acid (PPADS), or treatment with adenosine diphosphate-beta-S (ADP-beta-S), a selective P(2Y) agonist, led to a considerable prolongation in [Ca(2+)](i) responses compared with ATP. The prolonged time courses were consistent with sustained activation of store-operated channels (SOC) since SKF96365, an inhibitor of SOC, blocked this component of the response. RT-PCR data showed that microglia expressed no COX-2 either constitutively or following treatment of cells with ATP (100 microM for 8 h). However, treatment using ATP plus PPADS or with ADP-beta-S led to marked expression of COX-2. The enhanced COX-2 with ATP plus PPADS treatment was absent in the presence of SKF96365 or using Ca(2+)-free solution. Immunocytochemistry, using a specific anti-COX-2 antibody, also revealed a pattern of purinergic modulation whereby lack of P(2X) activation enhanced the production of COX-2 protein. These results suggest that modulation of subtypes of purinergic receptors regulates COX-2 in human microglia with a link involving SOC-mediated influx of Ca(2+).
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Affiliation(s)
- Hyun B Choi
- Department of Pharmacology and Therapeutics, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
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496
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Abstract
Parkinson's disease (PD) is a movement disorder that is characterized by progressive degeneration of the nigrostriatal dopamine system. Although dopamine replacement can alleviate symptoms of the disorder, there is no proven therapy to halt the underlying progressive degeneration of dopamine-containing neurons. Recently, increasing evidence from human and animal studies has suggested that neuroinflammation is an important contributor to the neuronal loss in PD. Moreover, the pro-inflammatory agent lipopolysaccharide itself can directly initiate degeneration of dopamine-containing neurons or combine with other environmental factor(s), such as the pesticide rotenone, to exacerbate such neurodegeneration. These effects provide strong support for the involvement of inflammation in the pathogenesis of PD. Furthermore, growing experimental evidence demonstrates that inhibition of the inflammatory response can, in part, prevent degeneration of nigrostriatal dopamine-containing neurons in several animal models of PD, suggesting that inhibition of inflammation might become a promising therapeutic intervention for PD.
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Affiliation(s)
- Hui Ming Gao
- Neuropharmacology Section, Laboratory of Pharmacology and Chemistry, National Institute of Environmental Health Sciences/National Institutes of Health, Research Triangle Park, NC 27709, USA.
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497
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Hirsch EC, Breidert T, Rousselet E, Hunot S, Hartmann A, Michel PP. The role of glial reaction and inflammation in Parkinson's disease. Ann N Y Acad Sci 2003; 991:214-28. [PMID: 12846989 DOI: 10.1111/j.1749-6632.2003.tb07478.x] [Citation(s) in RCA: 322] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The glial reaction is generally considered to be a consequence of neuronal death in neurodegenerative diseases such as Alzheimer's disease, Huntington's disease, and Parkinson's disease. In Parkinson's disease, postmortem examination reveals a loss of dopaminergic neurons in the substantia nigra associated with a massive astrogliosis and the presence of activated microglial cells. Recent evidence suggests that the disease may progress even when the initial cause of neuronal degeneration has disappeared, suggesting that toxic substances released by the glial cells may be involved in the propagation and perpetuation of neuronal degeneration. Glial cells can release deleterious compounds such as proinflammatory cytokines (TNF-alpha, Il-1beta, IFN-gamma), which may act by stimulating nitric oxide production in glial cells, or which may exert a more direct deleterious effect on dopaminergic neurons by activating receptors that contain intracytoplasmic death domains involved in apoptosis. In line with this possibility, an activation of proteases such as caspase-3 and caspase-8, which are known effectors of apoptosis, has been reported in Parkinson's disease. Yet, caspase inhibitors or invalidation of TNF-alpha receptors does not protect dopaminergic neurons against degeneration in experimental models of the disease, suggesting that manipulation of a single signaling pathway may not be sufficient to protect dopaminergic neurons. In contrast, the antiinflammatory drugs pioglitazone, a PPAR-gamma agonist, and the tetracycline derivative minocycline have been shown to reduce glial activation and protect the substantia nigra in an animal model of the disease. Inhibition of the glial reaction and the inflammatory processes may thus represent a therapeutic target to reduce neuronal degeneration in Parkinson's disease.
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Affiliation(s)
- E C Hirsch
- INSERM U289, Experimental Neurology and Therapeutics, Hôpital de la Salpêtrière, 75651 Paris Cedex 13, France.
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498
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Liu B, Gao HM, Hong JS. Parkinson's disease and exposure to infectious agents and pesticides and the occurrence of brain injuries: role of neuroinflammation. ENVIRONMENTAL HEALTH PERSPECTIVES 2003; 111:1065-73. [PMID: 12826478 PMCID: PMC1241555 DOI: 10.1289/ehp.6361] [Citation(s) in RCA: 195] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Idiopathic Parkinson's disease (PD) is a devastating movement disorder characterized by selective degeneration of the nigrostriatal dopaminergic pathway. Neurodegeneration usually starts in the fifth decade of life and progresses over 5-10 years before reaching the fully symptomatic disease state. Despite decades of intense research, the etiology of sporadic PD and the mechanism underlying the selective neuronal loss remain unknown. However, the late onset and slow-progressing nature of the disease has prompted the consideration of environmental exposure to agrochemicals, including pesticides, as a risk factor. Moreover, increasing evidence suggests that early-life occurrence of inflammation in the brain, as a consequence of either brain injury or exposure to infectious agents, may play a role in the pathogenesis of PD. Most important, there may be a self-propelling cycle of inflammatory process involving brain immune cells (microglia and astrocytes) that drives the slow yet progressive neurodegenerative process. Deciphering the molecular and cellular mechanisms governing those intricate interactions would significantly advance our understanding of the etiology and pathogenesis of PD and aid the development of therapeutic strategies for the treatment of the disease.
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Affiliation(s)
- Bin Liu
- Neuropharmacology Section, Laboratory of Pharmacology and Chemistry, National Institute of Environmental Health Sciences/National Institutes of Health, Research Triangle Park, North Carolina, USA.
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499
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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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500
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Wu DC, Teismann P, Tieu K, Vila M, Jackson-Lewis V, Ischiropoulos H, Przedborski S. NADPH oxidase mediates oxidative stress in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine model of Parkinson's disease. Proc Natl Acad Sci U S A 2003; 100:6145-50. [PMID: 12721370 PMCID: PMC156340 DOI: 10.1073/pnas.0937239100] [Citation(s) in RCA: 478] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2002] [Indexed: 11/18/2022] Open
Abstract
Parkinson's disease (PD) is a neurodegenerative disorder of uncertain pathogenesis characterized by a loss of substantia nigra pars compacta (SNpc) dopaminergic (DA) neurons, and can be modeled by the neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Both inflammatory processes and oxidative stress may contribute to MPTP- and PD-related neurodegeneration. However, whether inflammation may cause oxidative damage in MPTP and PD is unknown. Here we show that NADPH-oxidase, the main reactive oxygen species (ROS)-producing enzyme during inflammation, is up-regulated in SNpc of human PD and MPTP mice. These changes coincide with the local production of ROS, microglial activation, and DA neuronal loss seen after MPTP injections. Mutant mice defective in NADPH-oxidase exhibit less SNpc DA neuronal loss and protein oxidation than their WT littermates after MPTP injections. We show that extracellular ROS are a main determinant in inflammation-mediated DA neurotoxicity in the MPTP model of PD. This study supports a critical role for NADPH-oxidase in the pathogenesis of PD and suggests that targeting this enzyme or enhancing extracellular antioxidants may provide novel therapies for PD.
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Affiliation(s)
- Du-Chu Wu
- Department of Neurology, Columbia University, New York, NY 10032, USA
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