Metal chelator EGCG attenuates Fe(III)-induced conformational transition of α-synuclein and protects AS-PC12 cells against Fe(III)-induced death.

The fibrillation and aggregation of α-synuclein (AS), along with the conformational transition from random coil to β-sheet, are the critical steps in the development of Parkinson's disease (PD). It is acknowledged that iron accumulation in the brain may lead to the fibrillation of AS. However, (-)-epigallocatechin gallate (EGCG) can penetrate the blood-brain barrier, chelate metal ions, and inhibit the fibrillation of amyloid proteins. Therefore, EGCG is warranted to be investigated for its potential to cure amyloid-related diseases. In the present work, we sought to study the effects of EGCG on Fe(III)-induced fibrillation of AS on both molecular and cellular levels. We demonstrate that Fe(III) interacts with the amino residue of Tyr and Ala of AS, then accelerates the fibrillation of AS, and increases intracellular reactive oxygen species (ROS) in the AS transduced-PC12 cells (AS-PC12 cells). However, EGCG significantly inhibits this process by chelating Fe(III) and protects AS-PC12 cells against the toxicity induced by ROS and β-sheet-enriched AS fibrils. These findings yield useful information that EGCG might be a promising drug to prevent and treat the neurodegenerative diseases.