Abstract
Parkinson's disease (PD) is the second most common neurodegenerative disease. Oxidative stress is the most critical risk factor for neurodegenerative diseases, including Alzheimer's disease (AD) and Huntington's disease (HD). Numerous reports have demonstrated that oxidative stress aggravates cytotoxicity in dopaminergic neurons and accelerates the formation of protein inclusions. In addition, oxidative stress, such as 4-hydroxynonenal (HNE), oxidized protein, and dopamine quinone, are related to PD progression. DJ-1 is a PD-causative gene, and it plays a pivotal role as a sensor and eliminator of oxidative stress. Several studies have shown that oxidized DJ-1 (OxiDJ-1) formation is induced by oxidative stress. Hence, previous studies suggest that oxidized DJ-1 could be a biomarker for PD. We previously reported higher DJ-1 levels in Korean male PD patient urine exosomes than male non-PD controls. We speculate that OxiDJ-1 levels in PD patient urine might be higher than that in non-PD controls. In this study, we established an ELISA for OxiDJ-1 using recombinant DJ-1 treated with H2O2. Using Western blot assay and ELISA, we confirmed an increase of OxiDJ-1 from HEK293T cells treated with H2O2. Using our ELISA, we observed significantly higher, 2-fold, OxiDJ-1 levels in the urine of Korean PD patients than in non-PD controls.
Highlights
Parkinson’s disease is the second most common neurodegenerative disease, and its primary symptoms include tremor, bradykinesia, and rigidity. e progression of PD is associated with an increase in reactive oxygen species (ROS), including superoxide anion, hydrogen peroxide, hydroxyl radicals, singlet oxygen, and lipid peroxyl radicals [1]
It has been implicated that oxidative modification of proteins is accelerated by increase of ROS [3, 4]. e synthesis of dopamine quinone (DAQ) is mediated by the oxidation of dopamine, thereby initiating mitochondrial damage and generation of DAQ-conjugated cytosolic adducts [5, 6]. ese features are closely related to PD pathology
In order to establish an oxidized DJ-1 (OxiDJ-1) sandwich enzyme-linked immunosorbent assay (ELISA), we generated H2O2mediated OxiDJ-1 by treatment of recombinant His-DJ-1 protein with 5 mM H2O2 for 1.5 h to use as a standard protein for ELISA
Summary
Parkinson’s disease is the second most common neurodegenerative disease, and its primary symptoms include tremor, bradykinesia, and rigidity. e progression of PD is associated with an increase in reactive oxygen species (ROS), including superoxide anion, hydrogen peroxide, hydroxyl radicals, singlet oxygen, and lipid peroxyl radicals [1]. E progression of PD is associated with an increase in reactive oxygen species (ROS), including superoxide anion, hydrogen peroxide, hydroxyl radicals, singlet oxygen, and lipid peroxyl radicals [1]. Previous studies have revealed that 4-hydroxynonenal (HNE), a by-product of lipid peroxidation, is one of the most bioactive aldehydes, and oxidative stress initiates its production [2]. DJ-1 is known as a PD-causative gene, and its function is associated with oxidative stress in PD [7]. Loss of ROS scavenger function in DJ-1 showed enhanced cytotoxicity and increase of α-synuclein (α-syn) aggregates, which are known as a culprit of PD-pathogenesis [10,11,12]. A previous report proposed that oxidized DJ-1 (OxiDJ-1) would be an efficient biomarker for PD diagnosis [13]. Levels of DJ-1 in biofluids, such as cerebrospinal fluid (CSF), whole blood, plasma, serum, saliva, and urine, were investigated as a biomarker for PD (Table 1). ere were higher levels of OxiDJ-1 in the erythrocytes of PD patients than
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