The opposite effects of trehalose on 6-hydroxydopamine and 1-methyl-4- phenylpyridinium induced oxidative stress in human neuroblastoma SH-SY5Y cells

Abstract

6-hydroxydopamine (6-OHDA) and 1-methyl-4-phenylpyridinium (MPP+) are the most common neurotoxins used to induce experimental model of Parkinson’s disease both in vivo and in vitro. Neurotoxic action of 6-OHDA and MPP+ is mediated by oxidative stress, mitochondrial damage and induction of apoptotic cell death. Natural disaccharide trehalose exhibits antioxidative properties and stimulates removal of damaged proteins, and thus exhibits powerful neuroprotective effect in certain brain injury models. We investigated the effects of trehalose in 6-OHDA and MPP+ - induced oxidative stress and neurotoxicity in human neuroblastoma SH-SY5Y cells. The effects of trehalose on the cell viability and death were assessed by MTT, crystal violet, lactate dehydrogenase assay and AnnexinV-FITC/propidium iodide staining. The production of reactive oxygen species was analyzed by flow cytometry using redox-sensitive dyes dihydrorhodamine 123 (DHR) and MitoSOX Red. Further, activation of stress-related MAP kinases, p38 and JNK were investigated by immunoblot analysis. Our study demonstrated that trehalose pretreatment significantly improved cell viability and reduced neurotoxic effect of 6-OHDA, while slightly decreased cell viability and increased neurotoxic effect of MPP+. Trehalose decreased the number of 6-OHDA-induced apoptotic cells (shown by the reduced % of Annexin V+ and AnnexinV+ PI+ cells) whereas it increased apoptosis in MPP+ treated cells. Flow cytometric analysis of DHR and MitoSOX stained cells demonstrated that trehalose pretreatment significantly reduced 6-OHDA-triggered ROS and superoxide anion radical generation. However, in MPP+-treated neurons trehalose augmented oxidative stress and production of superoxide anion. Immunoblot analysis showed that trehalose significantly decreased p38 and JNK activation only in 6-OHDA treated cells. These results indicate that trehalose has different effects on oxidative stress induced by two different neurotoxins, 6-OHDA and MPP+, and suggests further exploration of the mechanism of its antioxidative action.