Differential effects of parkinsonism mimetics on SH-SY5Y neuroblastoma

Abstract

One of the pathological hallmarks of Parkinson’s diseases (PD) is the massive loss of dopaminergic neurons in substantia nigra and striatum. Human neuroblastoma, SH-SY5Y is a dopaminergic neuronal cell line which has long been used in PD research. However, little is known about the susceptibility of differentiated and non-differentiated SH-SY5Y neurons in response to parkinsonism mimetics. In this study, we aim to investigate their response to 6-hydroxydopamine (6-OHDA) and 1-methyl-4-phenylpyridinium (MPP+). Neuroblastoma cells were treated with or without 10 µM retinoic acid for 7 days prior to exposure to 6-OHDA or MPP+. Neurotoxicity was measured by MTT, release of LDH and activity of caspase-3. We observed that there was about 30% decrease in non-differentiated neurons exposed to 6-OHDA by MTT test while there was only about 5% decrease in differentiated neurons. Similarly, there was about 30% and 14% decrease in non-differentiated and differentiated neurons respectively after exposure to MPP+. For the release of LDH assay, there was about 4-fold increase in non-differentiated neurons exposed to 6-OHDA and only 2-fold increase in differentiated neurons. Similar results were obtained for neurons exposed to MPP+ in the same test; there was about 2-fold increase in non-differentiated neurons and 1.3-fold increase in differentiated neurons. Taken together, our results have shown that non-differentiated neuroblastoma cells are vulnerable to parkinsonism toxins. Differential effects of these toxins on neuroblastoma cells may attribute to the expression level of dopamine transporter.