Preventing Toxic Tangles: Tea Catechins Inhibit Amyloid Protein Aggregation

A common feature of numerous neurodegenerative disorders such as Parkinson's and Huntington's disease is the abnormal accumulation of aggregated proteins in distinct regions of the brain. Here, the author demonstrates that (-)- Epigallocatechin gallate (EGCG), a catechin present in green tea, is a potent inhibitor of this pathological process. EGCG prevents the aggregation of two different proteins by stabilizing an oligomeric conformation, leading aggregation-prone proteins on an alternative folding pathway in the misfolding cascade. This effect could be mediated by direct interaction between EGCG and proteins in an unfolded, "open" conformation. EGCG also reduces the toxicity caused by misfolded proteins in cell culture model systems, suggesting that the oligomeric protein species formed in the presence of the compound are not toxic to living cells. EGCG might therefore represent a chemical chaperone that can modulate misfolding and toxicity of proteins associated with neurodegenerative diseases and could provide the basis for the development of a novel pharmacotherapy for these fatal disorders.