1. ¹Intramural Research Program (IRP), Cellular Neurobiology Research Branch, Department of Health and Human Services (DHHS), National Institute on Drug Abuse (NIDA), National Institutes of Health (NIH), Baltimore, MD, USA
2. ²Molecular Neuropsychiatry Research Branch, IRP, NIDA, NIH, DHHS, Baltimore, MD, USA
3. ³Laboratory of Neuroscience, DHHS, National Institute of Aging, Baltimore, MD, USA
4. ⁴Buck Institute, Novato, CA, USA

Correspondence: , Buck Institute for Age Research, 8001 Redwood Boulevard, Novato, CA 94945, USA, Tel: +1 415 209 2211, Fax: +1 415 209 2230; E-mail: xzeng@buckinstitute.org

⁵These authors contributed equally to this work.

Received 9 February 2006; Revised 12 April 2006; Accepted 4 May 2006.

Abstract

Human embryonic stem cells (hESCs) can proliferate indefinitely yet also differentiate in vitro, allowing normal human neurons to be generated in unlimited numbers. Here, we describe the development of an in vitro neurotoxicity assay using human dopaminergic neurons derived from hESCs. We showed that the dopaminergic neurotoxin 1-methyl-4-phenylpyridinium (MPP⁺), which produces features of Parkinson's disease in humans, was toxic for hESC-derived dopaminergic neurons. Treatment with glial cell line-derived neurotrophic factor protected tyrosine hydroxylase-positive neurons against MPP⁺-induced apoptotic cell death and loss of neuronal processes as well as against the formation of intracellular reactive oxygen species. The availability of human dopaminergic neurons, derived from hESCs, therefore allows for the possibility of directly examining the unique features of human dopaminergic neurons with respect to their responses to pharmacological agents as well as environmental and chemical toxins.