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

Memory loss is an early symptom of Alzheimer's Disease (AD). The findings of Gong et al. (2006) now indicate that enhancing the activity of UCH-L1, a ubiquitin hydrolase, alleviates the synaptic dysfunction and memory loss associated with a mouse model of AD. This work also raises the question of what role UCH-L1 might play in other diseases involving protein aggregation, such as Parkinson's Disease.
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PMID:Improving synaptic function in a mouse model of AD. 1692 96

A recent meta-analysis observed a greater significant inverse association of the ubiquitin carboxy-terminal hydrolase L1 (UCHL1) S18Y variant with Parkinson's disease (PD) for Asian (predominantly Japanese) populations compared with Caucasian populations. We performed an independent case-control study in 335 PD and 341 control subjects with data from a Chinese population to investigate the age-of-onset effect of the UCHL1 variant in PD. The Y/Y and Y/S genotypes were less frequent in the PD young-onset group than in controls and the frequency of the Y alleles was higher in young controls compared to young-onset PD (age at examination <or= 65 years; P = 0.003). Multivariate analysis revealed the Y/Y genotype was significantly lower (P = 0.008) in the young-onset PD (Y/Y vs. S/S: odds ratio [OR]: 0.42; 95% confidence interval [CI]: 0.24, 0.74; S/Y vs. S/S: OR: 0.66, 95% CI: 0.41, 1.08) compared with controls, but this difference was not seen for the late-onset PD. Kaplan-Meier analysis carried out on PD subjects demonstrated that the Y/Y genotype was associated with a later onset of PD than Y/S plus S/S genotypes (P = 0.05). We provided an independent confirmation of the protective effect of the UCHL1 S18Y variant (Y/Y genotype) against PD in young Chinese subjects. Further functional studies of the S18Y variant in both cell and animal models will be of interest.
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PMID:Case-control study of UCHL1 S18Y variant in Parkinson's disease. 1694 65

To date 11 forms of familial Parkinson's disease (PD) have been mapped to different chromosome loci, of which 6 genes have been identified as the causative genes, i.e., alpha-synuclein (SNCA), parkin, UCH-L1, PINK1, DJ-1, and LRRK2. For UCH-L1, additional families with this mutation are necessary before concluding that UCH-L1 is the definite causative gene for PARK5, as only one family so far has been reported. SNCA, UCH-L1, and LRRK2 mutations cause autosomal dominant PD and the remaining gene mutations autosomal recessive PD. Age of onset tends to be younger in familial PD compared with sporadic PD, particularly so in autosomal recessive PD. Generally familial cases respond to levodopa quite nicely and progression of the disease tends to be slower. It is an interesting question how familial PD-causing proteins are mutually related each other. In this article, we review recent progress in genetics and molecular biology of familial PD.
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PMID:Progress in familial Parkinson's disease. 1701 29

To investigate the alpha-synuclein protein and its role in Parkinson's disease, we screened a library of random point mutants both in vitro and in yeast to find variants in an unbiased way that could help us understand the sequence-phenotype relationship. We developed a rapid purification method that allowed us to screen 59 synuclein mutants in vitro and discovered two double-point mutants that fibrillized slowly relative to wild-type, A30P, and A53T alpha-synucleins. The yeast toxicity of all of these proteins was measured, and we found no correlation with fibrillization rate, suggesting that fibrillization is not necessary for synuclein-induced yeast toxicity. We found that beta-synuclein was of intermediate toxicity to yeast, and gamma-synuclein was non-toxic. Co-expression of Parkinson's disease-related genes DJ-1, parkin, Pink1, UCH-L1, or synphilin, with synuclein, did not affect synuclein toxicity. A second screen, of several thousand library clones in yeast, identified 25 non-toxic alpha-synuclein sequence variants. Most of these contained a mutation to either proline or glutamic acid that caused a defect in membrane binding. We hypothesize that yeast toxicity is caused by synuclein binding directly to membranes at levels sufficient to non-specifically disrupt homeostasis.
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PMID:Relationships between the sequence of alpha-synuclein and its membrane affinity, fibrillization propensity, and yeast toxicity. 1722 66

Proteolytic degradation of unwanted proteins by the ubiquitin-proteasome system (UPS) is critical for normal maintenance of various cellular functions. Parkinson's disease (PD), one of the most prevalent neurodegenerative disorders, is characterized by prominent and irreversible nigral dopaminergic neuronal loss and intracellular protein aggregations. Epidemiological studies imply both environmental neurotoxins and genetic predisposition as potential risk factors for PD, though mechanisms underlying selective dopaminergic degeneration remain unclear. Studies with experimental PD models and postmortem PD brains have provided explicit evidence for mitochondria dysfunction and oxidative stress in PD pathogenesis. Recent identification of mutants in PINK1, DJ-1, Parkin, and LRRK-2 genes compliments the oxidative stress and mitochondrial dysfunction hypotheses in dopaminergic neuronal degeneration in PD. Mutants of alpha-synuclein, Uch-L1 and Parkin support the involvement of UPS dysfunction in PD. Furthermore, various Parkinsonian toxicants have been shown to impair mitochondrial function, redox balances, and to some extent protein degradation machinery. Because environmental exposure to various neurotoxic agents is considered a dominant risk for development of PD, the interrelationship between neurotoxicant exposures and UPS dysfunction must be clearly understood. Elucidation of this interrelationship will help clarify 2 areas: (i) whether UPS dysfunction in PD is a primary pathogenic factor leading to nigral neuronal death or if it simply occurs as a consequence of oxidative stress and mitochondrial dysfunction and (ii) the interaction of genes and environment in the acceleration of nigral dopaminergic degeneration by targeting UPS. We review the recent evidence for UPS deficits in dopaminergic degeneration triggered by neurotoxins.
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PMID:Environmental neurotoxic chemicals-induced ubiquitin proteasome system dysfunction in the pathogenesis and progression of Parkinson's disease. 1752 40

DJ-1 (PARK7) has been implicated in early onset and familial cases of Parkinson's disease (PD). We therefore mapped cellular activity patterns of the DJ-1 gene in human and rodent brain tissue with radioactive in-situ hybridization. In all three mammals mRNA expression was restricted mainly to neurons in all regions analyzed. White matter, such as crus cerebri and capsula interna appeared negative, suggesting that glial cells express DJ-1 at levels below the detection limit of our method. We compared DJ-1 mRNA expression to the neuronal marker UCH-L1, which has also been implicated in PD, and found lower levels for DJ-1 but very similar patterns of expression. Measurement of the signal intensity revealed that human frontal cortex of control cases expressed DJ-1 mRNA more abundantly than other regions such as substantia nigra in the midbrain. Comparing DJ-1 expression in dopamine neurons on hemi-sections from controls and patients we could not detect any difference between 14 controls, 8 idiopathic Parkinson and 5 schizophrenia cases. Of note, DJ-1 is expressed in several other tissues such as the liver, gastrointestinal tract, adrenal and pituitary gland and during embryonic development, while UCH-L1 has a strictly neuronal expression also outside the CNS. We conclude that DJ-1 and UCH-L1, like other genes linked to PD, are not expressed specifically in DA neurons, but instead generally in neurons. The abundant expression of DJ-1 in certain peripheral tissues and of UCH-L1 in peripheral neurons may also be of relevance for the spectrum of symptoms in different forms of PD.
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PMID:DJ-1 and UCH-L1 gene activity patterns in the brains of controls, Parkinson and schizophrenia patients and in rodents. 1759 67

Despite the discovery of at least five pathogenic genes in Parkinson disease (PD), the genetic etiology in the vast majority of PD remains to be clarified. Common genetic variants could act as susceptibility risk factors. Our previous meta-analysis of PD genetic association studies, over a 30-year period yielded four genes (N-acetylcysteine 2, monoamine oxidase B, glutathione transferase, and mitochondrial tRNA), as their common variants were found to be associated with PD. More recently, international collaborative studies and meta-analysis have identified the S18Y variant of ubiquitin carboxy-terminal hydrolase L1, Rep 1 variant of alpha-synuclein and tau H1 haplotype to be genetic susceptibility risk/protective factors. However, the most significant, common genetic risk factor in PD has been its association with the leucine-rich repeat kinase-2 (LRRK2) G2385R variant. We conducted an analysis of independent studies involving 2205 PD and 1817 controls and found the average carrier rate of G2385R variant to be about 9% in PD and 4% in controls (p < 0.001; odds ratio: 2.27; 95% confidence interval: 1.78-2.9). A higher frequency of G2385R carriers has been observed in familial PD when compared with sporadic patients. Based on current evidence, certain common genetic variants are likely to modulate the risk of PD.
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PMID:The role of common genetic risk variants in Parkinson disease. 1786 89

Parkinson's disease (PD) is a common disorder caused by degeneration of dopaminergic neurons in the substantia nigra and other brain areas. Mutations in several genes have been associated with both autosomal dominant PD and recessive early onset Parkinsonism (EOP). Genomic rearrangements such as deletions or multiplications of one or more exons represent a common mutational mechanism for most of these genes and are not detectable with routine mutation screening techniques. MLPA (Multiplex Ligation-dependent Probe Amplification), is a cheap, simple, rapid, and sensitive tool to detect exon dosage alterations and specific point mutations in selected genes. We tested the recently developed PD-MLPA assay by using 13 positive control samples carrying known mutations in SNCA, LRRK2, Parkin, PINK1, and DJ-1 genes. We then applied this technique to screen 16 EOP patients who were then cross-tested by quantitative PCR (qPCR). All the mutations present in the positive control samples were clearly detected by MLPA. Moreover, three novel Parkin rearrangements were identified among EOP patients and confirmed by qPCR. Only two samples generated false positive duplications of LRRK2 exon 1 and UCH-L1 exon 9, respectively. These results show that PD-MLPA assay can simultaneously and effectively detect rearrangements in most PD genes (SNCA, Parkin, PINK1, and DJ-1) as well as the LRRK2 G2019S common mutation. Thus, the use of this novel platform can improve the analysis of such mutations, facilitating comprehensive genetic testing in PD and EOP.
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PMID:Multiplex ligation-dependent probe amplification assay for simultaneous detection of Parkinson's disease gene rearrangements. 1791 26

alpha-Synuclein is mutated in Parkinson's disease (PD) and is found in cytosolic inclusions, called Lewy bodies, in sporadic forms of the disease. A fraction of alpha-synuclein purified from Lewy bodies is monoubiquitinated, but the role of this monoubiquitination has been obscure. We now review recent data indicating a role of alpha-synuclein monoubiquitination in Lewy body formation and implicating the autophagic pathway in regulating these processes. The E3 ubiquitin-ligase SIAH is present in Lewy bodies and monoubiquitinates alpha-synuclein at the same lysines that are monoubiquitinated in Lewy bodies. Monoubiquitination by SIAH promotes the aggregation of alpha-synuclein into amorphous aggregates and increases the formation of inclusions within dopaminergic cells. Such effect is observed even at low monoubiquitination levels, suggesting that monoubiquitinated alpha-synuclein may work as a seed for aggregation. Accumulation of monoubiquitinated alpha-synuclein and formation of cytosolic inclusions is promoted by autophagy inhibition and to a lesser extent by proteasomal and lysosomal inhibition. Monoubiquitinated alpha-synuclein inclusions are toxic to cells and recruit PD-related proteins, such as synphilin-1 and UCH-L1. Altogether, the new data indicate that monoubiquitination might play an important role in Lewy body formation. Decreasing alpha- synuclein monoubiquitination, by preventing SIAH function or by stimulating autophagy, constitutes a new therapeutic strategy for Parkinson's disease.
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PMID:Ubiquitination of alpha-synuclein and autophagy in Parkinson's disease. 1821 94

Parkinson's disease (PD) is a common neurodegenerative disorder in the aging population, affecting more than 1% over the age of 65 years. Certain rare forms of the disease are monogenic, representing 5-10% of PD patients, but there is increasing evidence that multiple genetic risk factors are important also for common forms of PD. To date, 13 genetic loci, PARK1-13, have been suggested for rare forms of PD such as autosomal dominant and autosomal recessive PD. At six of these loci, genes have been identified and reported by several groups to carry mutations that are linked to affected family members. Genes in which mutations have been linked to familial PD have also been shown to be candidate genes for idiopathic forms of PD, as those same genes may also carry other mutations that merely increase the risk. Four of the PARK genes, SNCA at PARK1, UCH-L1 at PARK5, PINK1 at PARK6 and LRRK2 at PARK8, have been implicated in sporadic PD. There are indeed multiple genetic risk factors that combine in different ways to increase or decrease risk, and several of these need to be identified in order to begin unwinding the causative pathways leading to the different forms of PD. In this review, we present the molecular genetics of PD that are understood today, to help explain the pathways leading to neurodegeneration.
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PMID:Parkinson's disease: a genetic perspective. 1827 77


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