Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0030567 (Parkinson's disease)
 63,064 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A growing body of evidence suggests oxidative stress involvement in neurodegenerative diseases; however, it remains to be determined whether oxidative stress is a cause, result, or epiphenomenon of the pathological processes. This review concerns the current issue, focusing on Alzheimer disease (AD), Parkinson disease (PD), and amyotrophic lateral sclerosis (ALS). Several studies have indicated that oxidative stress initially occurs in the disease-specific, site-restricted sources such as amyloid-beta in the cerebral cortex of AD brain, alpha-synuclein in the brain stem of PD brain, and glutamate receptor-coupled Ca2+ channel in the motor system of ALS spinal cord. Subsequent events in the neurons common to these diseases are glutamate-induced neurotoxicity and increased cytosolic Ca2+ levels, resulting in activation of Ca2+ -dependent enzymes including NADPH oxidase, cytosolic phospholipase A2, xanthine oxidase, and neuronal nitric oxide synthase (NOS). These enzymes produce reactive oxygen and nitrogen species (ROS/RNS), which oxidatively modify nucleic acid, lipid, sugar, and protein, leading to nuclear damage, mitochondrial damage, proteasome inhibition, and endoplasmic reticulum (ER) stress. Mitochondrial damage results in both ROS leakage from the electron transport system and Ca2+ release. Nuclear damage induces p53 activation, and proteasome inhibition reduces p53 degradation. The resultant increased p53 levels in the nucleus induce Bax activation and Bcl-2 inhibition, followed by a release of cytochrome c into the cytosol that truncates procaspase-9. ER stress triggers activation of caspase-12 as well as caspase-9 via the tumor necrosis factor (TNF) receptor-associated factor-2 / apoptosis-signaling kinase-1 / c-Jun N-terminal kinase pathway. Oxidative stress also stimulates astrocytes and microglia to yield and secrete cytokines such as TNFa and FasL that cause not only neuronal caspase-8 activation but also glial inflammatory response through induction of nuclear factor-kappaB-mediated, proinflammatory gene products including cytokines, chemokines, growth factors, cell adhesion molecules, and ROS/RNS-producing enzymes. The activated caspases truncate procaspase-3 to exert classical apoptosis. Moreover, oxidative DNA damage leads to the release and nuclear truncation of mitochondrial apoptosis-inducing kinase, which triggers apoptosis-like programmed cell death via cyclophilin A. These observations could indicate crucial implications for oxidative stress in several steps of the pathomechanisms of neurodegenerative diseases.
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PMID:[The role for oxidative stress in neurodegenerative diseases]. 1830 64

Kynurenic acid (KYNA), a tryptophan metabolite in the kynurenine pathway, is protective against various insults. However, the molecular mechanism of this protective effect has not been identified. In this study, we examined the protective effects of KYNA against 1-methyl-4-phenylpyridinium (MPP(+)), the best-characterized toxin inducing pathological changes resembling Parkinson's disease (PD), using SH-SY5Y and SK-N-SH human neuroblastoma cells. Pre-treatment of KYNA attenuated MPP(+)-induced neuronal cell death in SH-SY5Y and SK-N-SH cells. MPP(+)-induced cell death was preceded by increases in Bax expression and mitochondrial dysfunction, such as collapse of mitochondrial membrane potential (DeltaPsi(m)), release of cytochrome c from mitochondria into the cytoplasm, and increases in caspase-9/-3 activities. KYNA effectively inhibited all of these mitochondrial apoptotic processes. Our results indicate that KYNA plays a protective role by down-regulating Bax expression and maintaining mitochondrial function in MPP(+)-induced neuronal cell death, and suggest that KYNA may have therapeutic potential in PD.
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PMID:Kynurenic acid attenuates MPP(+)-induced dopaminergic neuronal cell death via a Bax-mediated mitochondrial pathway. 1846 30

It has been postulated that dihydroxyphenylacetic acid (DOPAC), a major dopamine metabolite, and nitric oxide (NO) induce mitochondrial dysfunction in a synergistic manner. We examined the combined effects of NO and DOPAC on PC-12 cells in terms of cell viability, nuclear morphology, mitochondrial parameters and cell death mechanisms. The apoptotic cell death induced by the NO-donor, S-nitroso-N-acetylpenicillamine (SNAP), was differently modulated by DOPAC as a function of DOPAC/cell ratios. Whereas below 200nmol/10(6) cells, DOPAC inhibited a typical apoptotic pathway induced by exposure the cells to the NO donor, above 200nmol DOPAC/10(6) cells, the cell death was not only enhanced but encompassed a distinct mechanism. Loading the cells with dopamine mimicked the effects of DOPAC. Specifically, the combination of DOPAC and NO induced an early mitochondrial membrane potential dissipation and ATP depletion followed by loss of cellular membrane integrity. Mitochondrial dysfunction was accompanied by the release of cytochrome c in both cases, NO individually and in combination with DOPAC, but caspase-3 and caspase-9 activation were only observed in the absence of DOPAC. DOPAC alone was ineffective. Thus, our results suggest a role for DOPAC as a modulator of cell fate and point to a pathway of cell death involving DOPAC and NO, via mechanisms that include mitochondrial dysfunction but do not involve the activation of the typical apoptotic caspase cascade. The significance of these results is discussed in connection with the mechanisms of cell death underlying Parkinson's disease.
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PMID:3,4-Dihydroxyphenylacetic acid (DOPAC) modulates the toxicity induced by nitric oxide in PC-12 cells via mitochondrial dysfunctioning. 1870 27

Parkinson disease is characterized by the progressive loss of dopaminergic neurons in the substantia nigra pars compacta. It has been proposed that dysfunction of the ubiquitin proteasome system plays an important role in the pathogenesis of Parkinson disease, but the mechanisms underlying ubiquitin proteasome system-related neuron degeneration are unknown. Here, we demonstrate that the proteasome inhibitor lactacystin induces phosphorylation of c-Jun N-terminal kinase (JNK) and c-Jun, the release of cytochrome c, activation of both caspase-9 and caspase-3, and sequential apoptosis of dopaminergic neurons in vitro. Most of these effects can be attenuated by the JNK inhibitor SP600125. Furthermore, infusion of lactacystin in rats in vivo also leads to phosphorylation of JNK before nigral neuron loss; chronic administration of SP600125 also blocks this loss. These results indicate that JNK is involved in proteasome inhibition-induced dopaminergic neuron degeneration through caspase-3-mediated apoptotic pathways, suggesting that this kinase may be a therapeutic target for the prevention of substantia nigra pars compacta degeneration in Parkinson disease patients.
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PMID:c-Jun N-terminal kinase mediates lactacystin-induced dopamine neuron degeneration. 1880 14

Alzheimer's disease (AD) is a progressive neurodegenerative disease for which there are few therapeutic regimens that influence the underlying pathogenic phenotypes. However, of the currently available therapies, exercise training is considered to be one of the best candidates for amelioration of the pathological phenotypes of AD. Therefore, we directly investigated exercise training to determine whether it was able to ameliorate the molecular pathogenic phenotypes in the brain using a neuron-specific enolase (NSE)/Swedish mutation of amyloid precursor protein (APPsw) transgenic (Tg) mice as a novel AD model. To accomplish this, Non-Tg and NSE/ APPsw Tg mice were subjected to exercise on a treadmill for 16 weeks, after which their brains were evaluated to determine whether any changes in the pathological phenotype-related factors had occurred. The results indicated (i) that amyloid beta-42 (Abeta-42) peptides were significantly decreased in the NSE/APPsw Tg mice following exercise training; (ii) that exercise training inhibited the apoptotic biochemical cascades, including cytochrome c, caspase-9, caspase-3 and Bax; (iii) that the glucose transporter-1 (GLUT-1) and brain-derived neurotrophic factor (BDNF) proteins induced by exercise training protected the neurons from injury by inducing the concomitant expression of genes that encode proteins such as superoxide dismutase-1 (SOD-1), catalase and Bcl-2, which suppress oxidative stress and excitotoxic injury; (iv) that heat-shock protein-70 (HSP-70) and glucose-regulated protein-78 (GRP-78) were significantly increased in the exercise (EXE) group when compared to the sedentary (SED) group, and that these proteins may benefit the brain by making it more resistant to stress-induced neuron cell damage; (v) and that exercise training contributed to the restoration of normal levels of serum total cholesterol, insulin and glucose. Taken together, these results suggest that exercise training represents a practical therapeutic strategy for human subjects suffering from AD. Moreover, this training has the potential for use in new therapeutic strategies for the treatment of other chronic disease including diabetes, cardiovascular and Parkinson's disease.
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PMID:Exercise training acts as a therapeutic strategy for reduction of the pathogenic phenotypes for Alzheimer's disease in an NSE/APPsw-transgenic model. 1881 61

Hydrogen sulfide (H(2)S) has been proposed as a novel neuromodulator, which plays critical roles in the central nervous system affecting both neurons and glial cells. However, its relationship with neurodegenerative diseases is unexplored. The present study was undertaken to investigate the effects of H(2)S on cell injury induced by rotenone, a commonly used toxin in establishing in vivo and in vitro Parkinson's disease (PD) models, in human-derived dopaminergic neuroblastoma cell line (SH-SY5Y). We report here that sodium hydrosulfide (NaHS), an H(2)S donor, concentration-dependently suppressed rotenone-induced cellular injury and apoptotic cell death. NaHS also prevented rotenone-induced p38- and c-Jun NH(2)-terminal kinase (JNK)-mitogen-activated protein kinase (MAPK) phosphorylation and rotenone-mediated changes in Bcl-2/Bax levels, mitochondrial membrane potential (DeltaPsi(m)) dissipation, cytochrome c release, caspase-9/3 activation and poly(ADP-ribose) polymerase cleavage. Furthermore, 5-hydroxydecanoate, a selective blocker of mitochondrial ATP-sensitive potassium (mitoK(ATP)) channel, attenuated the protective effects of NaHS against rotenone-induced cell apoptosis. Thus, we demonstrated for the first time that H(2)S inhibited rotenone-induced cell apoptosis via regulation of mitoK(ATP) channel/p38- and JNK-MAPK pathway. Our data suggest that H(2)S may have potential therapeutic value for neurodegenerative diseases, such as PD.
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PMID:Hydrogen sulfide inhibits rotenone-induced apoptosis via preservation of mitochondrial function. 1883 35

Parkinson's disease (PD) is a neurodegenerative disorder characterized by selective loss of dopaminergic neurons in the substantia nigra pars compacta. Although understanding of the pathogenesis of PD remains incomplete, increasing evidence from human and animal studies has suggested that oxidative stress is an important mediator in its pathogenesis. Astaxanthin (Asx), a potent antioxidant, has been thought to provide health benefits by decreasing the risk of oxidative stress-related diseases. This study examined the protective effects of Asx on 6-hydroxydopamine (6-OHDA)-induced apoptosis in the human neuroblastoma cell line SH-SY5Y. Pre-treatment of SH-SY5Y cells with Asx suppressed 6-OHDA-induced apoptosis in a dose-dependent manner. In addition, Asx strikingly inhibited 6-OHDA-induced mitochondrial dysfunctions, including lowered membrane potential and the cleavage of caspase 9, caspase 3, and poly(ADP-ribose) polymerase. In western blot analysis, 6-OHDA activated p38 MAPK, c-jun NH(2)-terminal kinase 1/2, and extracellular signal-regulated kinase 1/2, while Asx blocked the phosphorylation of p38 MAPK but not c-jun NH(2)-terminal kinase 1/2 and extracellular signal-regulated kinase 1/2. Pharmacological approaches showed that the activation of p38 MAPK has a critical role in 6-OHDA-induced mitochondrial dysfunctions and apoptosis. Furthermore, Asx markedly abolished 6-OHDA-induced reactive oxygen species generation, which resulted in the blockade of p38 MAPK activation and apoptosis induced by 6-OHDA treatment. Taken together, the present results indicated that the protective effects of Asx on apoptosis in SH-SY5Y cells may be, at least in part, attributable to the its potent antioxidative ability.
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PMID:Protective effects of astaxanthin on 6-hydroxydopamine-induced apoptosis in human neuroblastoma SH-SY5Y cells. 1901 78

The mycotoxin ochratoxin A (OTA), which is produced by Aspergillus and Penicillium subspecies, is a frequently present contaminant of food and feedstuffs. OTA exhibits a wide range of toxic activities including nephro- and hepatotoxicity. However, little is known regarding potential neurotoxic effects of OTA. In the present study primary neurons as well as SH-SY5Y neuronal cells were incubated with increasing concentrations of OTA (0.1-2.5 mumol/L). OTA treatment resulted in a dose-dependent increase in cytotoxicity in both neuronal cell types. Caspase-9 and caspase-3 were activated in response to OTA treatment. Furthermore, caspase inhibitors were effective in partly counteracting OTA induced neurocytotoxicity. OTA induced apoptosis was accompanied by a loss of mitochondria membrane potential. Overall, present data indicated that OTA is neurotoxic at relatively low concentrations. OTA induced neurotoxicity seems to be, at least party, mediated by apoptosis. OTA may contribute to the pathogenesis of neurodegenerative diseases (e.g. Alzheimer's and Parkinson's disease) in which apoptotic processes are centrally involved.
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PMID:Ochratoxin A induces apoptosis in neuronal cells. 1914 91

Aberrant mitochondrial function appears to play a central role in dopaminergic neuronal loss in Parkinson's disease (PD). 1-methyl-4-phenylpyridinium iodide (MPP(+)), the active metabolite of N-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), is a selective inhibitor of mitochondrial complex I and is widely used in rodent and cell models to elicit neurochemical alterations associated with PD. Recent findings suggest that Glycogen Synthase Kinase-3beta (GSK-3beta), a critical activator of neuronal apoptosis, is involved in the dopaminergic cell death. In this study, the role of GSK-3beta in modulating MPP(+)-induced mitochondrial dysfunction and neuronal death was examined in vivo, and in two neuronal cell models namely primary cultured and immortalized neurons. In both cell models, MPTP/MPP(+) treatment caused cell death associated with time- and concentration-dependent activation of GSK-3beta, evidenced by the increased level of the active form of the kinase, i.e. GSK-3beta phosphorylated at tyrosine 216 residue. Using immunocytochemistry and subcellular fractionation techniques, we showed that GSK-3beta partially localized within mitochondria in both neuronal cell models. Moreover, MPP(+) treatment induced a significant decrease of the specific phospho-Tyr216-GSK-3beta labeling in mitochondria concomitantly with an increase into the cytosol. Using two distinct fluorescent probes, we showed that MPP(+) induced cell death through the depolarization of mitochondrial membrane potential. Inhibition of GSK-3beta activity using well-characterized inhibitors, LiCl and kenpaullone, and RNA interference, prevented MPP(+)-induced cell death by blocking mitochondrial membrane potential changes and subsequent caspase-9 and -3 activation. These results indicate that GSK-3beta is a critical mediator of MPTP/MPP(+)-induced neurotoxicity through its ability to regulate mitochondrial functions. Inhibition of GSK-3beta activity might provide protection against mitochondrial stress-induced cell death.
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PMID:Involvment of cytosolic and mitochondrial GSK-3beta in mitochondrial dysfunction and neuronal cell death of MPTP/MPP-treated neurons. 1943 May 25

Alpha-synuclein (ASYN) is central in Parkinson's disease pathogenesis. Converging pieces of evidence suggest that the levels of ASYN expression play a critical role in both familial and sporadic Parkinson's disease. To elucidate the mechanism underlying wild type (WT) ASYN-mediated neurotoxicity, we have generated a novel Tet-Off SHSY-5Y cell line, conditionally expressing WT ASYN. Induction of human WT ASYN in retinoic acid-differentiated SHSY-5Y cells leads to accumulation of soluble ASYN oligomers, in the absence of inclusions, and to gradual cellular degeneration. Morphologically, the death observed is non-apoptotic. Caspases other than caspase 3, including caspase 9, are activated and caspase inhibition diminishes death by acting at a point upstream of cytochrome c release. Application of Scyllo-inositol, an oligomer-stabilizing compound, prevents neuronal death in this model. These findings are consistent with a model in which oligomeric ASYN triggers the initial activation of the apoptotic pathway, which is however blocked downstream of the mitochondrial checkpoint, thus leading to a death combining in a unique fashion both apoptotic and non-apoptotic features. This novel inducible cell model system may prove valuable in the deciphering of WT ASYN-induced pathogenic effects and in the assessment and screening of potential therapeutic strategies.
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PMID:Inducible over-expression of wild type alpha-synuclein in human neuronal cells leads to caspase-dependent non-apoptotic death. 1947 47


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