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1996, Annals of the New York Academy of Sciences
Parkinson disease (PD) is a chronic, progressive neurological disease that is associated with a loss of dopaminergic neurons in the substantia nigra pars compacta of the brain. The molecular mechanisms underlying the loss of these neurons still remain elusive. Oxidative stress is thought to play an important role in dopaminergic neurotoxicity. Complex I deficiencies of the respiratory chain account for the majority of unfavorable neuronal degeneration in PD. Environmental factors, such as neurotoxins, pesticides, insecticides, dopamine (DA) itself, and genetic mutations in PD-associated proteins contribute to mitochondrial dysfunction which precedes reactive oxygen species formation. In this mini review, we give an update of the classical pathways involving these mechanisms of neurodegeneration, the biochemical and molecular events that mediate or regulate DA neuronal vulnerability, and the role of PD-related gene products in modulating cellular responses to oxidative stress in the course of the neurodegenerative process.
Journal of Biomedical Research & Environmental Sciences, 2022
Parkinson’s Disease (PD) is a neurodegenerative disorder characterized by motor deficits caused by the loss of dopaminergic neurons in the Substantia Nigra (SN) and Ventral Tegmental Area (VTA). However, clinical data revealed that not only the dopaminergic system is affected in PD. Pharmacological models support the concept that modification of noradrenergic transmission can influence the PD-like phenotype induced by neurotoxins. Exposure to ambient pollutants such as air pollutants also can be adversely impacted the Central Nervous System (CNS) by the activation of proinflammatory pathways and reactive oxygen species. Thus, targeting neuroinflammation and oxidative stress can be a useful strategy to eliminate the obvious symptoms of neurodegeneration. Overall, in the current mini-review, we examined the neuroprotective role of noradrenaline in the model of oxidative stress and neuroinflammation.
Antioxidants & Redox Signaling, 2011
Parkinson's disease (PD) is a major world-wide health problem afflicting millions of the aged population. Factors that act on most or all cell types (pan-cellular factors), particularly genetic mutations and environmental toxins, have dominated public discussions of disease etiology. Although there is compelling evidence supporting an association between disease risk and these factors, the pattern of neuronal pathology and cell loss is difficult to explain without cell-specific factors. This article focuses on recent studies showing that the neurons at greatest risk in PD-substantia nigra pars compacta dopamine neurons-have a distinctive physiological phenotype that could contribute to their vulnerability. The opening of L-type calcium channels during autonomous pacemaking results in sustained calcium entry into the cytoplasm of substantia nigra pars compacta dopamine neurons, resulting in elevated mitochondrial oxidant stress and susceptibility to toxins used to create animal models of PD. This cellspecific stress could increase the negative consequences of pan-cellular factors that broadly challenge either mitochondrial or proteostatic competence. The availability of well-tolerated, orally deliverable antagonists for L-type calcium channels points to a novel neuroprotective strategy that could complement current attempts to boost mitochondrial function in the early stages of the disease.
Antioxidants
Parkinson’s disease (PD) is a chronic neurodegenerative condition affecting more than 1% of people over 65 years old. It is characterized by the preferential degeneration of nigrostriatal dopaminergic neurons, which is responsible for the motor symptoms of PD patients. The pathogenesis of this multifactorial disorder is still elusive, hampering the discovery of therapeutic strategies able to suppress the disease’s progression. While redox alterations, mitochondrial dysfunctions, and neuroinflammation are clearly involved in PD pathology, how these processes lead to the preferential degeneration of dopaminergic neurons is still an unanswered question. In this context, the presence of dopamine itself within this neuronal population could represent a crucial determinant. In the present review, an attempt is made to link the aforementioned pathways to the oxidation chemistry of dopamine, leading to the formation of free radical species, reactive quinones and toxic metabolites, and susta...
Neurochemistry International, 2007
Oxidative stress and apoptotic cell death have been implicated in the dopaminergic cell loss that characterizes Parkinson's disease. While factors contributing to apoptotic cell death are not well characterized, oxidative stress is known to activate an array of cell signaling molecules that participate in apoptotic cell death mechanisms. We investigated oxidative stress-induced cytotoxicity of hydrogen peroxide (H 2 O 2) in three cell lines, the dopaminergic mesencephalon-derived N27 cell line, the GABAergic striatum-derived M213-20 cell line, and the hippocampal HN2-5 cell line. N27 cells were more sensitive to H 2 O 2-induced cell death than M213-20 and HN2-5 cells. H 2 O 2 induced significantly greater increases in caspase-3 activity in N27 cells than in M213-20 cells. H 2 O 2-induced apoptotic cell death in N27 cells was mediated by caspase-3-dependent proteolytic activation of PKCδ. Gene expression microarrays were employed to examine the specific transcriptional changes in N27 cells exposed to 100μM H 2 O 2 for 4 hrs. Changes in genes encoding pro-or anti-apoptotic proteins included up-regulation of BIK, PAWR, STAT5B, NPAS2, Jun B, MEK4, CCT7, PPP3CC and PSDM3, while key down-regulated genes included BNIP3, NPTXR, RAGA, STK6, YWHAH, and MAP2K1. Overall, the changes indicate a modulation of transcriptional activity, chaperone activity, kinase activity, and apoptotic activity that appears highly specific, coordinated and relevant to cell survival. Utilizing this in vitro model to identify novel oxidative stress-regulated genes may be useful in unraveling the molecular mechanisms underlying dopaminergic degeneration in Parkinson's disease.
Free Radicals and Diseases, 2016
Epidemiological studies have found an increased risk of Parkinson's disease (PD) with environmental factors such as exposure to substances derived from industrial processes, use of agrochemicals, or living in a rural environment. The hypothesis that certain environmental toxins could be the source of the EP is supported by the discovery that chemicals such as herbicides paraquat, diquat, and the fungicide maneb are selectively toxic in nigrostriatal dopaminergic neurons. Also, one of the insecticides produced by plants, such as rotenone, and by-product of the synthesis of synthetic heroin MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) can be reproduced in animal models where neurochemicals, histopathological, and clinical characteristic of PD can be found. Interestingly, there are similarities in the chemical structure of paraquat and MPTP. Recent evidence exhibited that inflammation and oxidative stress play an essential role in the development of PD. So, in our laboratory we found that in an animal model melatonin decreases the products of lipid oxidation, nitric oxide metabolites, and the activity of cyclooxygenase 2, which are induced by an intraperitoneal injection of MPTP. This suggests that the neuroprotective effects of melatonin are partially attributed to its antioxidant scavenging and anti-inflammatory action.
2009
Abstract: Parkinson's disease (PD) is a progressive, age-related movement disorder, whose neuropathology is characterized by degeneration of the afferent pigmented neurons of the substantia nigra. Also associated with PD neuropathology are disrupted iron homeostasis, oxidative stress, and intracellular deposition of alpha-synuclein protein in Lewy bodies. Here we review oxidative stress mechanisms in Parkinson's disease, with emphasis on the relationship between oxidative stress and alpha-synuclein gene expression.
One of the common features occurring in several experimental models of neurodegenerative disorders is oxidative/nitrosative stress (OS/NS). This event induces a series of deleterious actions involving the primary formation of reactive oxygen and nitrogen species (ROS/RNS), affecting both the structure and function of different biological molecules, and leading to specific toxic processes that compromise cell redox status. Biomarkers are important indicators of normal and abnormal biological processes. Specific biochemical and genetic changes observed in different pathologies bring us comprehensive information regarding the nature of any particular disorder. Parkinson's disease (PD) is a chronic neurodegenerative disorder difficult to study, given the intricate events occurring in the pathology, and also because the resultant clinical phenotype fluctuates over time. At present, we have no definitive diagnostic test, and thus for clinicians there is still expectation that biomarkers will eventually help to diagnose symptomatic and presymptomatic disease, or provide surrogated end-points to demonstrate clinical efficacy of new treatments and neuroprotective therapies. In this review we explore current information on some potential biomarkers of OS/NS in PD models, with special emphasis on the mostrecent findings on this topic.
2020
Parkinson’s disease (PD) is a class of neurodegenerative disorders in which, complex interactions of genetic and environmental agents are involved in the etiology of both sporadic and familial PD cases. α-synuclein-encodingSNCAgene is known as one of the major genetic contributors of this disease.E46Kmutation inSNCAgene has not been investigated as intensive as otherSNCAgene mutations including A30P and A53T. In this study, to induce PD inDrosophilaflies,UAS-hSNCAWTandUAS-hSNCAE46Ktransgenic fly lines were constructed, whereSNCAgene was over-expressed in flies brains using GAL4-UAS genetic system. Western blot analysis of head samples ofSNCA-expressing flies verifiedSNCAexpression at protein level. Light and electron microscopy analysis of ommatidial structures were performed to verify neurodegeneration as a result of α-synuclein gene overexpression inDrosophilatransgenic flies. Confocal microscopy analysis of dopaminergic neuron clusters verified cell loss followingSNCAE46Kexpressi...
Oxidative Stress and Diseases, 2012
Acta medica Okayama, 2004
Parkinson's disease (PD) is a progressive neurodegenerative disease characterized by dopaminergic neuron-specific degeneration in the substantia nigra. A number of gene mutations and deletions have been reported to play a role in the pathogenesis of familial PD. Moreover, a number of pathological and pharmacological studies on sporadic PD and dopaminergic neurotoxin-induced parkinsonism have hypothesized that mitochondrial dysfunction, inflammation, oxidative stress, and dysfunction of the ubiquitin-proteasome system all play important roles in the pathogenesis and progress of PD. However, these hypotheses do not yet fully explain the mechanisms of dopaminergic neuron-specific cell loss in PD. Recently, the neurotoxicity of dopamine quinone formation by auto-oxidation of dopamine has been shown to cause specific cell death of dopaminergic neurons in the pathogenesis of sporadic PD and dopaminergic neurotoxin-induced parkinsonism. Furthermore, this quinone formation is closely li...
International Journal of Complementary & Alternative Medicine, 2021
In this review, we present evidence collected over a decade concerning signaling pathways and pathogenic mechanisms that are associated with oxidative stress in Parkinson's disease. Parkinson's is associated with several protein such as α-synuclein and signaling pathways such as Wnt signaling pathway. The review highlights the connection of the Wnt mediated pathway with other biological pathways that are known to have a role in neurodegeneration and the orchestrated role of several proteins in mitochondrial oxidative stress in Parkinsons. We have highlighted neuroprotective agents that eliminate the excess of reactive oxygen species and have a potential to be developed as therapeutics for Parkinson.
2000
Parkinson’s disease (PD) is the most common movement pathology, severely afflicting dopaminergic neurons within the substantia nigra (SN) along with non-dopaminergic, extra-nigral projection bundles that control circuits for sensory, associative, premotor, and motor pathways. Clinical, experimental, microanatomic, and biochemical evidence suggests PD involves multifactorial, oxidative neurodegeneration, and that levodopa therapy adds to the oxidative burden. The SN is uniquely vulnerable to oxidative damage, having a high content of oxidizable dopamine, neuromelanin, polyunsaturated fatty acids, and iron, and relatively low antioxidant complement with high metabolic rate. Oxidative phosphorylation abnormalities impair energetics in the SN mitochondria, also intensifying oxygen free radical generation. These pro-oxidative factors combine within the SN dopaminergic neurons to create extreme vulnerability to oxidative challenge. Epidemiologic studies and long-term tracking of victims o...
ACS chemical neuroscience, 2018
The preferential degeneration of dopaminergic neurons in the substantia nigra pars compacta is responsible for the motor impairment associated with Parkinson's disease. Dopamine is a highly reactive molecule, which is usually stored inside synaptic vesicles where it is stabilized by the ambient low pH. However, free cytosolic dopamine can auto-oxidize, generating reactive oxygen species, and lead to the formation of toxic quinones. In the present work, we have analyzed the mechanisms through which the dysfunction of dopamine homeostasis could induce cell toxicity, by focusing in particular on the damage induced by dopamine oxidation products at the mitochondrial level. Our results indicate that dopamine derivatives affect mitochondrial morphology and induce mitochondrial membrane depolarization, leading to a reduction of ATP synthesis. Moreover, our results suggest that opening of the mitochondrial transition pore induced by dopamine-derived quinones may contribute to the specif...
Oxidative Medicine and Cellular Longevity, 2012
There is extensive evidence in Parkinson's disease of a link between oxidative stress and some of the monogenically inherited Parkinson's disease-associated genes. This paper focuses on the importance of this link and potential impact on neuronal function. Basic mechanisms of oxidative stress, the cellular antioxidant machinery, and the main sources of cellular oxidative stress are reviewed. Moreover, attention is given to the complex interaction between oxidative stress and other prominent pathogenic pathways in Parkinson's disease, such as mitochondrial dysfunction and neuroinflammation. Furthermore, an overview of the existing genetic mouse models of Parkinson's disease is given and the evidence of oxidative stress in these models highlighted. Taken into consideration the importance of ageing and environmental factors as a risk for developing Parkinson's disease, geneenvironment interactions in genetically engineered mouse models of Parkinson's disease are also discussed, highlighting the role of oxidative damage in the interplay between genetic makeup, environmental stress, and ageing in Parkinson's disease.
Antioxidants & Redox Signaling, 2012
Aim: Oxidative stress has long been considered as a major contributing factor in the pathogenesis of Parkinson's disease. However, molecular sources for reactive oxygen species in Parkinson's disease have not been clearly elucidated. Herein, we sought to investigate whether a superoxide-producing NADPH oxidases (NOXs) are implicated in oxidative stress-mediated dopaminergic neuronal degeneration. Results: Expression of various Nox isoforms and cytoplasmic components were investigated in N27, rat dopaminergic cells. While most of Nox isoforms were constitutively expressed, Nox1 expression was significantly increased after treatment with 6-hydroxydopamine. Rac1, a key regulator in the Nox1 system, was also activated. Striatal injection of 6-hydroxydopamine increased Nox1 expression in dopaminergic neurons in the rat substantia nigra. Interestingly, it was localized into the nucleus, and immunostaining for DNA oxidative stress marker, 8oxo-dG, was increased. Nox1expression was also found in the nucleus of dopaminergic neurons in the substantia nigra of Parkinson's disease patients. Adeno-associated virus-mediated Nox1 knockdown or Rac1 inhibition reduced 6-hydroxydopamine-induced oxidative DNA damage and dopaminergic neuronal degeneration significantly. Innovation: Nox1/Rac1 could serve as a potential therapeutic target for Parkinson's disease. Conclusion: We provide evidence that dopaminergic neurons are equipped with the Nox1/Rac1 superoxide-generating system. Stress-induced Nox1/Rac1 activation causes oxidative DNA damage and neurodegeneration. Reduced dopaminergic neuronal death achieved by targeting Nox1/Rac1, emphasizes the impact of oxidative stress caused by this system on the pathogenesis and therapy in Parkinson's disease.
Biochimica et Biophysica Acta (BBA) - Molecular Basis of Disease, 1997
Ž . The dopaminergic neurotoxin N-methyl,4-phenyl-1,2,3,6 tetrahydropyridine MPTP causes a syndrome in primates and Ž . humans which mimics Parkinson's disease PD in clinical, pathological, and biochemical findings, including diminished activity of complex I in the mitochondrial electron transport chain. Reduced complex I activity is found in sporadic PD and can be transferred through mitochondrial DNA, suggesting a mitochondrial genetic etiology. We now show that MPTP Ž q . treatment of mice and N-methylpyridinium MPP exposure of human SH-SY5Y neuroblastoma cells increases oxygen free radical production and antioxidant enzyme activities. Cybrid cells created by transfer of PD mitochondria exhibit similar characteristics; however, PD cybrids' antioxidant enzyme activities are not further increased by MPP q exposure, as are the activities in control cybrids. PD mitochondrial cybrids are subject to metabolic and oxidative stresses similar to MPTP parkinsonism and provide a model to determine mechanisms of oxidative damage and cell death in PD. q 1997 Elsevier Science B.V.
Parkinson's disease (PD) is the most common disease of motor system degeneration and, after Alzheimer's disease, the second most common neurodegenerative disease. 1 Parkinson's disease takes a heavy toll in mental anguish, lost productivity, and health care expenditures. PD prominently features dopamine transmitter insufficiency, and current management is almost exclusively reliant on dopamine replacement drugs. But, while these drugs are initially effective in most patients, they do not slow the underlying degeneration in the area of the brain most affected, the substantia nigra (SN). Their effectiveness declines over time and their adverse effects become increasingly more troublesome. Broader options for long-term management are urgently needed.
Experimental Neurology, 2005
Parkinson's disease (PD) is a neurodegenerative disorder characterized by a dramatic loss of dopaminergic neurons in the substantia nigra (SN). Among the many pathogenic mechanisms thought to contribute to the demise of these cells, dopamine-dependent oxidative stress has classically taken center stage due to extensive experimental evidence showing that dopamine-derived reactive oxygen species and oxidized dopamine metabolites are toxic to nigral neurons. In recent years, however, the involvement of neuro-inflammatory processes in nigral degeneration has gained increasing attention. Not only have activated microglia and increased levels of inflammatory mediators been detected in the striatum of deceased PD patients, but a large body of animal studies points to a contributory role of inflammation in dopaminergic cell loss. Recently, postmortem examination of human subjects exposed to the parkinsonism-inducing toxin, 1-methyl-4phenyl-1,2,3,6-tetrahydropyridine (MPTP), revealed the presence of activated microglia decades after drug exposure, suggesting that even a brief pathogenic insult can induce an ongoing inflammatory response. Perhaps not surprisingly, non-steroidal anti-inflammatory drugs (NSAIDs) have been shown to reduce the risk of developing PD. In the past few years, various pathways have come to light that could link dopamine-dependent oxidative stress and microglial activation, finally ascribing a pathogenic trigger to the chronic inflammatory response characteristic of PD.
Science's STKE, 2006
Parkinson’s disease (PD) is a common neurodegenerative disorder that is most often sporadic, but in some cases it can be inherited as a simple Mendelian trait. The most important pathological feature of the disease is the death of brainstem dopaminergic neurons in the substantia nigra, which leads to characteristic motor symptoms. The etiology of PD remains unknown, but mitochondrial dysfunction and oxidative stress may contribute actively to the underlying pathomechanism. New studies suggest that K ATP channel activation may represent a downstream effector of these two cellular anomalies.
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