Laboratoire Matière et Systèmes Complexes

Video Seminar. Thursday 16th April 11h00

Tannin-controlled micelles and fibrils of proteins : preventing Alzheimer and designing biomimetic materials

Dražen Zanchi Laboratoire Matière et Systèmes Complexes, UMR 7057, Université de Paris

Control and understanding of amyloid fibril formation is emerging topic in biomedical contexts (therapeutic applications for neurodegenerative diseases, physiologically acceptable adhesion and tissue engineering), in functional materials including nanotechnologies, and in food and nutrition applications.

I will report on the perturbation/control of amyloid fibrils formation by addition of tannins. We will focus on proteins that form micelles. This case is attracting considerable attention since early studies on amyloid $\beta$ peptide fibrillation (causing Alzheimer) in which dynamic micellar oligomers determine the aggregation mechanisms. Since, micelles-fibril interplay was reported for a number of other proteins. In particular, amyloid nucleus, hierarchical fibril formation, transient species including micelles/oligomers etc. have been identified in a number of cases by light scattering and time resolved small-angle x-ray (SAXS) scattering experiments. Small tannins show promising amyloid inhibitory activity for pathogenic proteins. In nature, tannins protect plants from viruses, fungi, bacteria and higher herbivores by mechanisms based on physical interactions with proteins. High affinity of tannins for proteins makes tannins interesting for studying their impact on the formation of amyloid aggregates. A small tannin from the green tea epigallocatechin-gallate (EGCG) is a particularly strong anti-amyloid agent. It is known that EGCG prevents protein from forming amyloid fibrils by co-assembling with neuro-toxic proteins into non-toxic micelle-like aggregates.