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Parkinson’s Disease
Volume 2014, Article ID 878935, 12 pages
http://dx.doi.org/10.1155/2014/878935
Research Article

Dopamine Cytotoxicity Involves Both Oxidative and Nonoxidative Pathways in SH-SY5Y Cells: Potential Role of Alpha-Synuclein Overexpression and Proteasomal Inhibition in the Etiopathogenesis of Parkinson's Disease

1Department of Biochemistry, Institute of Post-Graduate Medical Education & Research, 244B, Acharya J. C. Bose Road, Kolkata 700020, India
2Department of Neuroscience, Burke-Cornell Medical Research Institute, 785 Mamaroneck Avenue, White Plains, NY 10605, USA
3Department of Neuroscience, Rosalind Franklin University of Medicine and Science, 3333 Green Bay Road, North Chicago, IL 60064, USA
4DNA Laboratory, Anthropological Survey of India, 27, J. N. Road, Kolkata 700016, India
5National Institute of Cholera and Enteric Diseases, P-33 C.I.T. Road, Kolkata 700010, India

Received 6 November 2013; Revised 19 February 2014; Accepted 25 February 2014; Published 2 April 2014

Academic Editor: Nobutaka Hattori

Copyright © 2014 Kalpita Banerjee et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Background. The cytotoxic effects of dopamine (DA) on several catecholaminergic cell lines involve DA oxidation products like reactive oxygen species (ROS) and toxic quinones and have implications in the pathogenesis of sporadic Parkinson's disease (PD). However, many molecular details are yet to be elucidated, and the possible nonoxidative mechanism of dopamine cytotoxicity has not been studied in great detail. Results. Cultured SH-SY5Y cells treated with DA (up to 400 M) or lactacystin (5 M) or DA (400 M) plus N-acetylcysteine (NAC, 2.5 mM) for 24 h are processed accordingly to observe the cell viability, mitochondrial dysfunctions, oxidative stress parameters, proteasomal activity, expression of alpha-synuclein gene, and intracellular accumulation of the protein. DA causes mitochondrial dysfunction and extensive loss of cell viability partially inhibited by NAC, potent inhibition of proteasomal activity marginally prevented by NAC, and overexpression with accumulation of intracellular alpha-synuclein partially preventable by NAC. Under similar conditions of incubation, NAC completely prevents enhanced production of ROS and increased formation of quinoprotein adducts in DA-treated SH-SY5Y cells. Separately, proteasomal inhibitor lactacystin causes accumulation of alpha-synuclein as well as mitochondrial dysfunction and cell death. Conclusions. DA cytotoxicity includes both oxidative and nonoxidative modes and may involve overexpression and accumulation of alpha-synuclein as well as proteasomal inhibition.