title: DT-Diaphorase Prevents Aminochrome-Induced Alpha-Synuclein Oligomer Formation and Neurotoxicity.
abstract: It was reported that aminochrome induces the formation of alpha synuclein (SNCA) oligomers during dopamine oxidation. We found that DT-diaphorase (NQO1) prevents the formation of SNCA oligomers in the presence of aminochrome determined by Western blot, transmission electron microscopy, circular dichroism, and thioflavin T fluorescence, suggesting a protective role of NQO1 by preventing the formation of SNCA oligomers in dopaminergic neurons. In order to test NQO1 protective role in SNCA neurotoxicity in cellular model, we overexpressed SNCA in both RCSN-3 cells (wild-type) and RCSN-3Nq7 cells, which have constitutive expression of a siRNA against NQO1. The expression of SNCA in RCSN-3SNCA and RCSN-3Nq7SNCA cells increased 4.2- and 4.4-fold, respectively. The overexpression of SNCA in RCSN-3Nq7SNCA cells induces a significant increase in cell death of 2.8- and 3.2-fold when they were incubated with 50 and 70 µM aminochrome, respectively. The cell death was found to be of apoptotic character determined by annexin/propidium iodide technique with flow cytometry and DNA laddering. A Western blot demonstrated that SNCA in RCSN-3SNCA is only found in monomer form both in the presence of 20 µM aminochrome or cell culture medium contrasting with RCSN-3Nq7SNCA cells where the majority SNCA is found as oligomer. The antioligomer compound scyllo-inositol induced a significant decrease in aminochrome-induced cell death in RCSN-3Nq7SNCA cells in comparison to cells incubated in the absence of scyllo-inositol. Our results suggest that NQO1 seems to play an important role in the prevention of aminochrome-induced SNCA oligomer formation and SNCA oligomers neurotoxicity in dopaminergic neurons.
authors: *Department of Molecular and Clinical Pharmacology, ICBM, Faculty of Medicine, University of Chile; Faculty of Engineering, Central University of Chile; Department of Biology, University of Valparaiso, Chile; and Department Basic Sciences, University of Santo Tomas, Viña del Mar, Chile.
authors: Patricia
authors: P
authors: Muñoz
authors: *Department of Molecular and Clinical Pharmacology, ICBM, Faculty of Medicine, University of Chile; Faculty of Engineering, Central University of Chile; Department of Biology, University of Valparaiso, Chile; and Department Basic Sciences, University of Santo Tomas, Viña del Mar, Chile *Department of Molecular and Clinical Pharmacology, ICBM, Faculty of Medicine, University of Chile; Faculty of Engineering, Central University of Chile; Department of Biology, University of Valparaiso, Chile; and Department Basic Sciences, University of Santo Tomas, Viña del Mar, Chile.
authors: Sergio
authors: S
authors: Cardenas
authors: *Department of Molecular and Clinical Pharmacology, ICBM, Faculty of Medicine, University of Chile; Faculty of Engineering, Central University of Chile; Department of Biology, University of Valparaiso, Chile; and Department Basic Sciences, University of Santo Tomas, Viña del Mar, Chile.
authors: Sandro
authors: S
authors: Huenchuguala
authors: *Department of Molecular and Clinical Pharmacology, ICBM, Faculty of Medicine, University of Chile; Faculty of Engineering, Central University of Chile; Department of Biology, University of Valparaiso, Chile; and Department Basic Sciences, University of Santo Tomas, Viña del Mar, Chile.
authors: Andrea
authors: A
authors: Briceño
authors: *Department of Molecular and Clinical Pharmacology, ICBM, Faculty of Medicine, University of Chile; Faculty of Engineering, Central University of Chile; Department of Biology, University of Valparaiso, Chile; and Department Basic Sciences, University of Santo Tomas, Viña del Mar, Chile.
authors: Eduardo
authors: E
authors: Couve
authors: *Department of Molecular and Clinical Pharmacology, ICBM, Faculty of Medicine, University of Chile; Faculty of Engineering, Central University of Chile; Department of Biology, University of Valparaiso, Chile; and Department Basic Sciences, University of Santo Tomas, Viña del Mar, Chile *Department of Molecular and Clinical Pharmacology, ICBM, Faculty of Medicine, University of Chile; Faculty of Engineering, Central University of Chile; Department of Biology, University of Valparaiso, Chile; and Department Basic Sciences, University of Santo Tomas, Viña del Mar, Chile.
authors: Irmgard
authors: I
authors: Paris
authors: *Department of Molecular and Clinical Pharmacology, ICBM, Faculty of Medicine, University of Chile; Faculty of Engineering, Central University of Chile; Department of Biology, University of Valparaiso, Chile; and Department Basic Sciences, University of Santo Tomas, Viña del Mar, Chile jsegura@med.uchile.cl.
authors: Juan
authors: J
authors: Segura-Aguilar
mesh_terms: D001578:Benzopyrans / Q000633:toxicity*; D001704:Biopolymers / Q000378:metabolism*; D002460:Cell Line; D006801:Humans; D016660:NAD(P)H Dehydrogenase (Quinone) / Q000378:metabolism*; D009420:Nervous System / Q000187:drug effects*; D051844:alpha-Synuclein / Q000378:metabolism*
chemical_list: D001578:Benzopyrans; D001704:Biopolymers; D051844:alpha-Synuclein; D016660:NAD(P)H Dehydrogenase (Quinone); C447479:NQO1 protein, human
keywords: NQO1; Parkinsons’s disease; alpha synuclein; aminochrome; dopamine; dopaminergic neurons; neuroprotection; oligomers
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