Genetics of Parkinson's disease
ABSTRACT Parkinson's disease is the second most common neurodegenerative disorder and affects 2% of the population over the age of 60 years. Due to the increasing proportion of elderly individuals in developed countries, Parkinson's disease and related neurodegenerative disorders represent a growing burden on the health care system. In the majority of cases, the cause of the disease is still unknown, and its elucidation remains one of the major challenges of the neurosciences. Recent findings in rare genetic forms of Parkinson's disease have allowed the development of novel animal models, providing a basis for a better understanding of the molecular pathogenesis of the disease, setting the stage for the development of novel treatment strategies.
Several novel genes for monogenic forms of Parkinson's disease, such as PINK-1 for an autosomal-recessive early-onset variant, and LRRK2 for a relatively common late-onset autosomal-dominant form have recently been discovered, and several novel animal models have been generated on the basis of genes that had been found earlier.
The combination of genetic, pathologic and molecular findings provide increasing evidence that the pathways identified through the cloning of different disease genes are interacting on different levels and share several major pathogenic mechanisms.
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ABSTRACT: Alpha-synuclein (α-syn) is a soluble protein highly enriched in presynaptic terminals of neurons. Accumulation of α-syn as intracellular filamentous aggregates is a pathological feature of sporadic and familial forms of Parkinson's disease (PD). Changes in α-syn post-translational modifications, as well as mitochondrial dysfunction and oxidative stress constitute key pathogenic events of this disorder. Here we assessed the correlation between α-syn phosphorylation at serine 129 (Ser129), the formation of reactive oxygen species (ROS) and mitochondrial dysfunction in SH-SY5Y cells expressing A53T mutant or wild-type (WT) α-syn, exposed to ferrous iron (FeSO4) and rotenone (complex I inhibitor). Under basal conditions, prolonged expression of A53T mutant α-syn altered mitochondria morphology, increased superoxide formation and phosphorylation at Ser129, which was linked to decreased activity of protein phosphatase 2A (PP2A). Exposure to FeSO4 or rotenone enhanced intracellular ROS levels, including superoxide anions, in both types of cells, along with α-syn Ser129 phosphorylation and mitochondrial depolarization. Most of these changes were largely evident in A53T mutant α-syn expressing cells. Overall, the data suggest that stimuli that promote ROS formation and mitochondrial alterations highly correlate with mutant α-syn phosphorylation at Ser129, which may precede cell degeneration in PD.Molecular and Cellular Neuroscience 09/2014; DOI:10.1016/j.mcn.2014.08.002 · 3.73 Impact Factor
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ABSTRACT: The increasing data provides enough evidences confirming the involvement of free radicals and other reactive oxygen species (ROS) superoxide radical (. O 2−), nitric oxide (NO. ), hydrogen peroxide (H2O2) and hydroxyl radicals (. OH) in a number of physiological and pathological processes. Imbalance between levels of ROS resulting in the body and the capacity of antioxidant defense mechanisms occur oxidative stress (OS). OS is related to a number of structural and functional damages to cells and is involved in the pathogenesis of many diseases, including neurodegenerative diseases such as Alzheimer’s disease, Parkinson’s disease (PD), amyotrophic lateral sclerosis, and Huntington disease. Defects in oxidative phosphorylation and oxidative damage play an important role in neurodegenerative diseases. The aim of this study was to investigate some biomarkers of OS such as the level of lipid peroxidation measured as malondialdehyde (MDA) reactive products and activity of antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT) in the blood of PD patients compared with control group of healthy volunteers. By the present research we report higher levels of MDA products and an imbalance in SOD and CAT enzyme activities in PD patients compared to the control group.Comparative Clinical Pathology 03/2012; 22(2). DOI:10.1007/s00580-012-1407-8
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ABSTRACT: Parkinson's disease is one of the most common neurodegenerative disorders associated with aging, reaching ∼ 2% of individuals over 65 years. Knowledge achieved in the last decade about the genetic basis of Parkinson's disease clearly shows that genetic factors play an important role in the etiology of this disorder. Exon dosage variations account for a high proportion of Parkinson's disease mutations, mainly for PARKIN gene. In the present study, we screened genomic rearrangements in SNCA, PARKIN, PINK1 and DJ-1 genes in 102 Brazilian Parkinson's disease patients with early onset (age of onset ⩽ 50 years), using the multiplex ligation-dependent probe amplification method. Family history was reported by 24 patients, while 78 were sporadic cases. Screening of exon dosage revealed PARKIN and PINK1 copy number variations, but no dosage alteration was found in SNCA and DJ-1 genes. Most of the carriers harbor heterozygous deletions or duplications in the PARKIN gene and only one patient was found to have a deletion in PINK1 exon 1. Data about dosage changes are scarce in the Brazilian population, which stresses the importance of including exon dosage analysis in Parkinson's disease genetic studies.Disease markers 02/2012; 32(3):173-8. DOI:10.3233/DMA-2011-0873 · 2.17 Impact Factor