d-arg-dmt-lys-phe-nh2 and Neuroblastoma

Excessive mitochondrial free radical production and the related mitogen-activated protein kinase P38 (P38 MAPK) activation are key regulators in the pathogenesis of high glucose-induced cell stress. Increasing evidence has emphasized the impact of hyperglycemia on neurons and the consequent neuronal stresses eventually resulting in neurodegeneration and neuronal death. In this study, we employed a novel mitochondria-targeted antioxidant, SS31 peptide, on high glucose-insulted neuroblastoma cells (SH-SY5Y). Our results showed that high glucose promoted significantly increased P38 phosphorylation which was efficiently suppressed by the application of the SS31 peptide under the experimental conditions. The inhibition of high glucose-induced P38 activation by the SS31 peptide was associated with the impact of the SS31 peptide on attenuating high glucose-induced mitochondrial ROS (reactive oxygen species) elevation and mitochondrial membrane potential collapse. The addition of SS31 peptide significantly attenuated high-gluose-induced apoptosis. Therefore, our study suggests that elimination of high glucose-induced mitochondrial oxidative stress helps to rescue SH-SY5Y cells from high glucose-related P38 MAPK pathway disturbances, and the SS31 peptide has the potential to serve as a new treatment strategy against hyperglycemia-instigated neuronal perturbations.

Topics: Antioxidants; Apoptosis; Cell Line, Tumor; Glucose; Humans; MAP Kinase Signaling System; Mitochondria; Neuroblastoma; Oligopeptides; p38 Mitogen-Activated Protein Kinases; Phosphorylation; Reactive Oxygen Species; Signal Transduction

The purpose of this study was to determine the neurotoxicity of two commonly used herbicides: picloram and triclopyr and the neuroprotective effects of the mitochondria-targeted antioxidant, SS31. Using mouse neuroblastoma (N2a) cells and primary neurons from C57BL/6 mice, we investigated the toxicity of these herbicides, and protective effects of SS1 peptide against picloram and triclopyr toxicity. We measured total RNA content, cell viability and mRNA expression of peroxiredoxins, neuroprotective genes, mitochondrial-encoded electron transport chain (ETC) genes in N2a cells treated with herbicides and SS31. Using primary neurons from C57BL/6 mice, neuronal survival was studied in neurons treated with herbicides, in neurons pretreated with SS31 plus treated with herbicides, neurons treated with SS31 alone, and untreated neurons. Significantly decreased total RNA content, and cell viability in N2a cells treated with picloram and triclopyr were found compared to untreated N2a cells. Decreased mRNA expression of neuroprotective genes, and ETC genes in cells treated with herbicides was found compared to untreated cells. Decreased mRNA expression of peroxiredoxins 1-6 in N2a cells treated with picloram was found, suggesting that picloram affects the antioxidant enzymes in N2a cells. Immunofluorescence analysis of primary neurons revealed that decreased neuronal branching and degenerating neurons in neurons treated with picloram and triclopyr. However, neurons pretreated with SS31 prevented degenerative process caused by herbicides. Based on these results, we propose that herbicides--picloram and triclopyr appear to damage neurons, and the SS31 peptide appears to protect neurons from herbicide toxicity.

Topics: Animals; Antioxidants; Cell Line, Tumor; Cell Survival; Electron Transport Chain Complex Proteins; Forkhead Box Protein O1; Forkhead Transcription Factors; Glycolates; Herbicides; Mice; Mice, Inbred C57BL; Neuroblastoma; Neurons; Oligopeptides; Oxidative Stress; Peroxiredoxins; Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; Picloram; Receptors, N-Methyl-D-Aspartate; Reverse Transcriptase Polymerase Chain Reaction; RNA; RNA, Messenger; Trans-Activators; Transcription Factors; Transcription, Genetic