Hexagonal Boron Nitride Nanoparticles for Inhibition of Small Fragment Tau Aggregation.

Abstract

The aberrant folding of the Tau protein is correlated with several neurodegenerative diseases, such as Alzheimer's and other tauopathies. Recent studies on the neurotoxic species of Tau have identified some smaller nucleating domains of the full-length protein to initiate Tau aggregation and are shown as potential therapeutic targets in Tau pathology. Two hexapeptides, namely, PHF6 (³⁰⁶VQIVYK³¹¹) and PHF6* (²⁷⁵VQIINK²⁸⁰), have been recognized as the most important aggregation-prone Tau fragments among all. Currently, low-dimensional nanomaterials have shown a plethora of applications in bionanomedicine, including the treatment of amyloid diseases. Hexagonal boron nitride (h-BN) nanoparticles, analogous to carbon nanomaterials, have become potential candidates in this field due to their lower cytotoxicity compared to carbon nanoparticles and biocompatibility. In this study, we have explored the aggregation pattern of PHF6 and PHF6* and the effects of a two-dimensional (2D) h-BN nanosheet (BNNS) on these peptide oligomerizations. Atomistic simulations reveal that the PHF6-PHF6 homomer aggregation is highly favored due to the aromatic π-π interaction between the Tyr residues; furthermore, the heteromeric interaction between PHF6 and PHF6* is stronger than the self-association of PHF6* homomers. In the presence of BNNS, the peptides get absorbed on the nanosurface through weak hydrophobic interactions and aromatic π-π stacking and remain in their monomeric random coil structure. Also, the h-BN nanosheet can destabilize the preformed oligomers of the hexapeptides, hence providing a new direction toward the use of h-BN and other related nanomaterials as potential antiaggregating agents against amyloid deposition.