Amyloid self-assembly of α-synuclein (αSyn) is linked to the pathogenesis of Parkinson's disease (PD). Type 2 diabetes (T2D) has recently emerged as a risk factor for PD. Cross-interactions between their amyloidogenic proteins may act as molecular links. In fact, fibrils of islet amyloid polypeptide (IAPP) (T2D) can cross-seed αSyn amyloidogenesis and αSyn and IAPP colocalize in PD brains. Inhibition of both self- and IAPP-cross-seeded αSyn amyloidogenesis could thus interfere with PD pathogenesis. Here we show that macrocyclic peptides, designed to mimic IAPP self-/cross-interaction sites and previously found to inhibit amyloidogenesis of IAPP and/or Alzheimer's disease (AD) amyloid-β peptide Aβ40(42), are nanomolar inhibitors of both self- and IAPP-cross-seeded amyloid self-assembly of αSyn. Anti-amyloid function is mediated by nanomolar affinity interactions with αSyn via three αSyn regions which are identified as key sites of both αSyn self-assembly and its cross-interactions with IAPP. We also show that the peptides block Aβ42-mediated cross-seeding of αSyn as well. Based on their broad spectrum anti-amyloid function and additional drug-like features, these peptides are leads for multifunctional anti-amyloid drugs in PD, T2D, AD, and their comorbidities, while the identified αSyn key segments are valuable targets for novel, multi-site targeting amyloid inhibitors in PD and related synucleinopathies.
FörderungenDeutsche Forschungsgemeinschaft Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) DFG under Germany's Excellence Strategy within the framework of the Munich Cluster for Systems Neurology JPND Consortium, SynOD ,,alpha-Synuclein OMICS - Federal Ministry of Education and Research, BMBF Studienstiftung des Deutschen Volkes e. V