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)

Parkinson's disease (PD) is a common neurodegenerative disorder characterized by loss of dopaminergic neurons in the substantia nigra. Several lines of evidence strongly implicate mitochondrial dysfunction as a major causative factor in PD, although the molecular mechanisms responsible for mitochondrial dysfunction are poorly understood. Recently, loss-of-function mutations in the parkin gene, which encodes a ubiquitin-protein ligase, were found to underlie a familial form of PD known as autosomal recessive juvenile parkinsonism (AR-JP). To gain insight into the molecular mechanism responsible for selective cell death in AR-JP, we have created a Drosophila model of this disorder. Drosophila parkin null mutants exhibit reduced lifespan, locomotor defects, and male sterility. The locomotor defects derive from apoptotic cell death of muscle subsets, whereas the male sterile phenotype derives from a spermatid individualization defect at a late stage of spermatogenesis. Mitochondrial pathology is the earliest manifestation of muscle degeneration and a prominent characteristic of individualizing spermatids in parkin mutants. These results indicate that the tissue-specific phenotypes observed in Drosophila parkin mutants result from mitochondrial dysfunction and raise the possibility that similar mitochondrial impairment triggers the selective cell loss observed in AR-JP.
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PMID:Mitochondrial pathology and apoptotic muscle degeneration in Drosophila parkin mutants. 1264 58

The etiopathogenesis of Parkinson's disease (PD) has been elusive. Recently, several lines of evidence have converged to suggest that defects in the ubiquitin-proteasome system and proteolytic stress underlie nigral pathology in both familial and sporadic forms of the illness. In support of this concept, mutations in alpha-synuclein that cause the protein to misfold and resist proteasomal degradation cause familial PD. Similarly, mutations in two enzymes involved in the normal function of the ubiquitin-proteasome system, parkin and ubiquitin C-terminal hydrolase L1, are also associated with hereditary PD. Furthermore, structural and function defects in 26/20S proteasomes with accumulation and aggregation of potentially cytotoxic abnormal proteins have been identified in the substantia nigra pars compacta of patients with sporadic PD. Thus, a defect in protein handling appears to be a common factor in sporadic and the various familial forms of PD. This hypothesis may also account for the vulnerability of the substantia nigra pars compacta in PD, why the disorder is age related, and the nature of the Lewy body. It has also facilitated the development of experimental models that recapitulate the behavioral and pathological features of PD, and hopefully will lead to the development of novel neuroprotective therapies for the disorder.
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PMID:Proteolytic stress: a unifying concept for the etiopathogenesis of Parkinson's disease. 1266

A method for analysis of deletions and duplications of individual exons and groups of exons in the parkin gene (PARK2) in both homozygous and heterozygous states has been developed. The method is based on semiquantitative polymerase chain reaction (PCR). The method has been used for analysis of the frequency of deletions in gene PARK2 in patients with idiopathic Parkinson's disease from Bashkortostan. Two unrelated patients have been found to carry a deletion of the 12th (last) exon of gene PARK2. Possibly, this deletion has caused the disease in the given patients.
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PMID:[Analysis of deletion mutations in the PARK2 gene in idiopathic Parkinson's disease]. 1266 18

Parkin, the most commonly mutated gene in familial Parkinson's disease, encodes an E3 ubiquitin ligase. A number of candidate substrates have been identified for parkin ubiquitin ligase action including CDCrel-1, o-glycosylated alpha-synuclein, Pael-R, and synphilin-1. We now show that parkin promotes the ubiquitination and degradation of an expanded polyglutamine protein. Overexpression of parkin reduces aggregation and cytotoxicity of an expanded polyglutamine ataxin-3 fragment. Using a cellular proteasome indicator system based on a destabilized form of green fluorescent protein, we demonstrate that parkin reduces proteasome impairment and caspase-12 activation induced by an expanded polyglutamine protein. Parkin forms a complex with the expanded polyglutamine protein, heat shock protein 70 (Hsp70) and the proteasome, which may be important for the elimination of the expanded polyglutamine protein. Hsp70 enhances parkin binding and ubiquitination of expanded polyglutamine protein in vitro suggesting that Hsp70 may help to recruit misfolded proteins as substrates for parkin E3 ubiquitin ligase activity. We speculate that parkin may function to relieve endoplasmic reticulum stress by preserving proteasome activity in the presence of misfolded proteins. Loss of parkin function and the resulting proteasomal impairment may contribute to the accumulation of toxic aberrant proteins in neurodegenerative diseases including Parkinson's disease.
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PMID:Parkin facilitates the elimination of expanded polyglutamine proteins and leads to preservation of proteasome function. 1267 55

Mutations in the parkin gene cause the majority of cases of familial-linked Parkinson's disease, and mounting evidence suggests that parkin may play a role in idiopathic disease. Previous reports suggest that parkin may respond to and relieve, via E3-ligase activity, cellular stress at the endoplasmic reticulum caused by the accumulation of unfolded proteins. However, parkin's relationship to the mammalian unfolded protein response is unclear. Here, we comprehensively evaluate endogenous parkin in SH-SY5Y neuroblastomas at the promoter, RNA, and protein levels in response to unfolded protein stress induced by tunicamycin. While we find strong up-regulation of genes linked to the unfolded protein stress pathway, we detect no significant changes in parkin. These data suggest a lack of association between parkin and the unfolded protein response in SH-SY5Y cells.
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PMID:Parkin is not regulated by the unfolded protein response in human neuroblastoma cells. 1268 85

We present a review on the genetic and environmental factors implicated in the aetiology of Parkinson's disease. The environmental hypothesis was strongly suggested about 20 years ago after the report of a parkinsonian syndrome in young adults that were intoxicated by a neurotoxin called MPTP which selectively destroys nigrostriatal dopaminergic neurons. Several chemical products used in herbicides and pesticides are similar structurally to MPTP, including paraquat, diquat and rotenone. Epidemiological studies have revealed an increased risk for Parkinson's disease with the use of pesticides and herbicides or the consumption of well water in rural areas of industrialised countries. However, it has not been possible to identify any causative environmental chemical agent in the aetiology of Parkinson's disease despite intensive research. Comparatively, the genetic hypothesis of Parkinson's disease has gained considerable interest during the last decade. Epidemiological studies reveal a family history in 10-25 p. cent Parkinson's disease patients. Several large kindreds with autosomal dominant Parkinson's disease associated with mutations of alpha-synuclein gene (PARK 1) were recently described. alpha-synuclein is a constituant of Lewy bodies, the hallmark of idiopathic Parkinson's disease. However, alpha-synuclein gene mutations are rare as opposed to parkin gene mutations (PARK 2), which are frequently found in autosomal recessive and sporadic young onset Parkinson's disease patients. Other genes or locus are implicated in autosomal dominant familial cases (PARK 3, 4 and 5). Nevertheless, a pure genetic origin can be demonstrated only in a minority of Parkinson's disease patients. Investigation of the possible interaction between genes and environment and of several candidate genes gave contradictory results, notably concerning the association between allelic variants of CYP2D6 gene and the occurrence of Parkinson's disease. In conclusion, the aetiology of Parkinson's disease remains unknown. There are probably several types or causes of Parkinson's disease. In most cases, this heterogeneity could be attributed both to genetic and environmental factors.
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PMID:[Genetic and environmental factors of Parkinson's disease] 1269 Mar 11

We present a review on the genetic and environmental factors implicated in the aetiology of Parkinson's disease. The environmental hypothesis was strongly suggested about 20 years ago after the report of a parkinsonian syndrome in young adults that were intoxicated by a neurotoxin called MPTP which selectively destroys nigrostriatal dopaminergic neurons. Several chemical products used in herbicides and pesticides are similar structurally to MPTP, including paraquat, diquat and rotenone. Epidemiological studies have revealed an increased risk for Parkinson's disease with the use of pesticides and herbicides or the consumption of well water in rural areas of industrialised countries. However, it has not been possible to identify any causative environmental chemical agent in the aetiology of Parkinson's disease despite intensive research. Comparatively, the genetic hypothesis of Parkinson's disease has gained considerable interest during the last decade. Epidemiological studies reveal a family history in 10-25 p. 100 Parkinson's disease patients. Several large kindreds with autosomal dominant Parkinson's disease associated with mutations of alpha-synuclein gene (PARK 1) were recently described. alpha-synuclein is a constituant of Lewy bodies, the hallmark of idiopathic Parkinson's disease. However, alpha-synuclein gene mutations are rare as opposed to parkin gene mutations (PARK 2), which are frequently found in autosomal recessive and sporadic young onset Parkinson's disease patients. Other genes or locus are implicated in autosomal dominant familial cases (PARK 3, 4 and 5). Nevertheless, a pure genetic origin can be demonstrated only in a minority of Parkinson's disease patients. Investigation of the possible interaction between genes and environment and of several candidate genes gave contradictory results, notably concerning the association between allelic variants of CYP2D6 gene and the occurrence of Parkinson's disease. In conclusion, the aetiology of Parkinson's disease remains unknown. There are probably several types or causes of Parkinson's disease. In most cases, this heterogeneity could be attributed both to genetic and environmental factors.
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PMID:[Genetics and environmental factors of Parkinson disease]. 1269 Jun 60

An autosomal recessive juvenile-onset form of Parkinson's disease (AR-JP) is caused by loss-of-function mutations of the parkin gene, which encodes a ubiquitin-protein ligase. Three recent reports demonstrate that parkin can protect neurons from diverse cellular insults, including alpha-synuclein toxicity, proteasomal dysfunction, Pael-R accumulation, and kainate-induced excitotoxicity. These findings suggest a central role for parkin in maintaining dopaminergic neuronal integrity and strengthen the link between AR-JP and the more common sporadic form of Parkinson's disease.
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PMID:Parkin: a multipurpose neuroprotective agent? 1269 60

Lesions in the parkin gene cause early onset Parkinson's disease by a loss of dopaminergic neurons, thus demonstrating a vital role for parkin in the survival of these neurons. Parkin is inactivated by caspase cleavage, and the major cleavage site is after Asp126. Caspases responsible for parkin cleavage were identified by several experimental paradigms. Transient coexpression of caspases and wild type parkin in HEK-293 cells identified caspase-1, -3, and -8 as efficient inducers of parkin cleavage whereas caspase-2, -7, -9, and -11 did not induce cleavage. A D126A parkin mutation abrogates cleavage induced by caspase-1 and -8, but not by caspase-3. In anti-Fas-treated Jurkat T cells, parkin cleavage was inhibited by caspase inhibitors hFlip and CrmA (but not by X-linked inhibitor of apoptosis (XIAP)), indicating that caspase-8 (but not caspase-3) is responsible for the parkin cleavage in this model. Moreover, induction of apoptosis in caspase-3-deficient MCF7 cells, either by caspase-1 or -8 overexpression or by tumor necrosis factor-alpha treatment, led to parkin cleavage. These results demonstrate that caspase-1 and -8 can directly cleave parkin and suggest that death receptor activation and inflammatory stress can cause loss of the ubiquitin ligase activity of parkin, thus causing accumulation of toxic parkin substrates and triggering dopaminergic cell death.
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PMID:Caspase-1 and caspase-8 cleave and inactivate cellular parkin. 1269 30

This Update reviews developments in the pathophysiology and treatment of Parkinson disease during the past several years. In the area of pathophysiology, studies have addressed the contribution of environmental factors such as caffeine and pesticides. Large-scale epidemiologic studies have also expanded the role genetic factors are thought to play. Detailed studies of kindreds with familial Parkinson disease due to alpha-synuclein and parkin have catalyzed basic science investigations into the pathologic mechanisms of the disease. These studies have led to the development of a pathophysiologic model of Parkinson disease that emphasizes abnormal protein aggregation. Studies of treatment have clarified the relative roles of l-dopa and dopamine agonists in early Parkinson disease and shown the potential for surgical interventions, particularly deep-brain stimulation, to relieve the symptoms of advanced, medically refractory disease.
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PMID:Update on Parkinson disease. 1269 88


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