Epigallocatechin Gallate Protects against TNFα- or H2O2- Induced Apoptosis by Modulating Iron Related Proteins in a Cell Culture Model.

Abstract

Oxidative stress, iron dysregulation, and inflammation have been implicated in the pathogenesis of Parkinson's disease (PD). Considering the entwined relationship among these factors, epigallocatechin gallate (EGCG) may be a good candidate for PD treatment due to its protective effects against those factors. The objective of this study is to determine whether EGCG protects N27 dopaminergic neuronal cells from H2O2 - and TNFα- induced neurotoxicity. Seven treatments were included: control, H2O2, TNFα, FeSO4, H2O2+EGCG, TNFα+EGCG, FeSO4+EGCG. Cells were pretreated with 10μM EGCG, followed by 50μM H2O2, 30ng/ml TNFα or 50μM FeSO4. Neuroprotective effects of EGCG were assessed by cell viability assay, caspase-3 activity, intracellular reactive oxygen species (ROS) generation, and iron related protein expressions. Caspase-3 activity was increased to 2.8 fold (P<0.001) and 1.5 fold (P<0.01) with H2O2 and TNFα treatment; However, EGCG pretreatment significantly decreased the caspase activity by 50.2% (P<0.001) and 30.1% (P<0.05). Similarly, cell viability was reduced to 69.2% (P<0.01) and 89% (P<0.01) by H2O2 and TNFα, which was partially blocked by EGCG pretreatment. Also, EGCG significantly (P<0.001) protected against H2O2- induced ROS in a time dependent manner. In addition, both H2O2 and TNFα significantly (P<0.05) upregulated hepcidin expression and marginally reduced ferroportin (Fpn) expression unlike iron treatment alone. Collectively, our results show that EGCG protects against both TNFα- and H2O2- induced neuronal apoptosis. The observed neuroprotection may be through the inhibition of oxidative stress and inflammation which is possibly mediated mainly by hepcidin and partially by Fpn.