Toxicity of serum albumin on microglia upon seeding effect of amyloid peptide.

We demonstrate in vitro cross-seeding of bovine serum albumin (BSA) in the presence of Aβ25-35 and their cytotoxic effects on microglial cells. To investigate the cross-seeding of BSA in the presence of Aβ25-35 fibrils, we examined how Aβ25-35 fibrils can function as seeds to trigger and accelerate BSA fibrillogenesis using ThT, intrinsic fluorescence, ANS fluorescence and transmission electron microscopy (TEM). Moreover, the effects of these fibrils on microglial viability were measured using MTT and Annexin V/propidium iodide (PI) staining. Although Aβ25-35 is toxic against microglia, it acted as seed and affected the aggregation pathway and accelerated the fibrillogenesis of BSA in vitro, resulted in an enhanced cytotoxic effect in comparison with Aβ25-35 or BSA alone. These observations thought to be helpful to understand the molecular mechanism of enhanced toxicity due to the coexistence of the aggregation prone proteins/peptides,. then cross-seeding effect on microglial cells that may involve in neurodegenerative diseases such as Alzheimer's disease (AD).