Biophysical analysis of angiotensin II and amyloid-β cross-interaction in aggregation and membrane disruption

Amyloid-β (Aβ) aggregation is a hallmark of Alzheimer's disease. Endogenous peptides in the same environment may influence Aβ aggregation via direct interaction. This study explores the cross-interaction between Aβ and angiotensin II (AngII), a neuropeptide of the renin-angiotensin system, using biophysical assays and in silico modeling. Thioflavin T fluorescence, circular dichroism, and Congo Red assays show that AngII modestly reduces Aβ aggregation and membrane disruption in a dose-dependent manner. Liposome leakage assays confirm decreased membrane disruption. Modeling suggests AngII binds preferentially to disordered Aβ conformers. These findings indicate that AngII may modulate early amyloidogenic events and contribute to amyloid homeostasis, offering insights into the interplay between neuropeptides and amyloid pathology.