Transduced Tat-α-Synuclein Protects against Oxidative Stress In vitro and In vivo

Abstract

Parkinson's disease (PD) is a common neurodegenerative disorder and is characterized by the progressive loss of dopaminergic neurons in the substantia nigra. Although many studies showed that the aggregation of alpha-synuclein might be involved in the pathogenesis of PD, its protective properties against oxidative stress remain to be elucidated. In this study, human wild type and mutant alpha-synuclein genes were fused with a gene fragment encoding the nine amino acid transactivator of transcription (Tat) protein transduction domain of HIV-1 in a bacterial expression vector to produce a genetic in-frame WT Tat-alpha-synuclein (wild type) and mutant Tat-alpha-synucleins (mutants; A30P and A53T), respectively, and we investigated the protective effects of wild type and mutant Tat-alpha-synucleins in vitro and in vivo. WT Tat-alpha-synuclein rapidly transduced into an astrocyte cells and protected the cells against paraquat induced cell death. However, mutant Tat-alpha-synucleins did not protect at all. In the mice models exposed to the herbicide paraquat, the WT Tat-alpha-synuclein completely protected against dopaminergic neuronal cell death, whereas mutants failed in protecting against oxidative stress. We found that these protective effects were characterized by increasing the expression level of heat shock protein 70 (HSP70) in the neuronal cells and this expression level was dependent on the concentration of transduced WT Tat-alpha-synuclein. These results suggest that transduced Tat-alpha-synuclein might protect cell death from oxidative stress by increasing the expression level of HSP70 in vitro and in vivo and this may be of potential therapeutic benefit in the pathogenesis of PD.

The proteomic approach in Parkinson's disease

“…Actually, asynuclein transfected cells were more resistant to the oxidative insult induced by DA, whereas cells transfected with a control vector behaved like wild-type ones. This finding was in agreement with the observation that expression of the TAT-a-synuclein fusion protein at sub-micromolar level is protective toward oxidative stress [61,62]. Increased viability was referred to a more than two-fold increase in the levels of DJ-1, a PD-related protein [63].…”

Protective Role of Heat Shock Proteins in Parkinson’s Disease

“…The authors found increased expression of HSP70 in mice treated with both paraquat and Tat-␣ -syn, and this increase was directly dependent on the concentration of the wt Tat-wt-␣ -syn. They suggested that the decreased cell death was due to the increased level of HSP70, which was able to antagonize the oxidative cell stress [81] . To better reproduce the key feature of human PD transgenic ␣ -syn, animal models have been studied.…”

“…In animal PD models, the induced increase in HSP70 synthesis protects against soluble ␣-syn toxicity and oxidative stress [81].…”

Transduced Tat-DJ-1 Protein Protects against Oxidative Stress-Induced SH-SY5Y Cell Death and Parkinson Disease in a Mouse Model

“…Although Tat fusion proteins have been used to deliver therapeutic proteins in vitro and in vivo, the exact mechanism remains unclear. In previous studies, we have shown in vitro and in vivo that various transduced fusion proteins efficiently protected against cell death Choi et al, 2006a;2006b;Eum et al, 2004;Kim et al, 2009;Kwon et al, 2000).…”

“…Prolonged exposure to ROS contributes significantly to the pathological processes of a number of human diseases and is a major factor in the cause of various neurodegenerative disorders including PD (Hald and Lotharius, 2005;Pong et al, 2001;Rastogi et al, 2006;Tamagno et al, 2003). In a previous study, we showed that the administration of a herbicide paraquat (1,1′-dimethy-4,4′-bipyridinium) triggers selective dopaminergic neuronal cell death and the exposure of mice to which is an effective model for studying the pathological aspects of PD (Choi et al, 2006a). Also, another study has suggested that paraquat is associated with an increased risk of PD (Synder and D'Amato, 1985).…”