INVESTIGATION OF PROTEIN MISFOLDING MECHANISMS IN AMYLOIDOSIS: FROM BIOCHEMISTRY TO THERAPEUTICS

Abstract

Protein misfolding and aggregation are hallmarks of amyloidosis, a group of debilitating disorders characterized by the deposition of insoluble amyloid fibrils in tissues and organs. This study attempts to examine the biochemistry of protein misfolding in amyloidosis based on three amyloidogenic proteins, namely β-amyloid (Aβ), α-synuclein, and transthyretin (TTR). In vitro biochemical assays, spectroscopic analyses, and electron microscopy were employed to assess various structural transitions from native proteins to toxic oligomers and fibrils. The binding of Thioflavin T and Congo red confirmed the progressive formation of amyloid, while CD and FTIR studies showed a much larger increase in β-sheet content during the aggregation process. The classical fibrillar morphologies were shown by electron microscopy. Toxicity assays indicated that early oligomeric intermediates had a greater detrimental effect on cell viability than mature fibrils. Besides, docking studies coupled with molecular dynamics simulations predicted that curcumin and EGCG are able to bind well to aggregation-prone regions, inhibiting fibril formation and thereby having the potential to be effective therapeutics. Doxycycline showed a moderate inhibitory effect, which may be caused by destabilizing the fibril. These results provide a greater understanding of the contribution of protein misfolding in amyloidosis and advocate for the further use of small molecules as putative therapeutic agents. Future investigations would need to take these compounds through a pharmacological efficacy and safety evaluation in vivo. This work interconnects biochemical mechanisms to clinical practice in regard to amyloid-related diseases.