Identification of Crocin as a New hIAPP Amyloid Inhibitor via a Simple Yet Highly Biospecific Screening System

Abstract

Amylin (hIAPP) amyloid formation plays an important role in the pathogenesis of type 2 diabetes (T2D), which makes it a promising therapeutic target for T2D. In this study, we established a screening tool for identifying chemicals affecting hIAPP amyloid formation based on a reported genetic tool, which constantly tracks protein aggregates in Saccharomyces cerevisiae. In order to obtain the hIAPP with better aggregation ability, the gene of hIAPP was tandemly ligated to create 1×, 2×, 4× or 6×‐hIAPP expressing strains. By measuring the cell density and fluorescence intensity of green fluorescent protein (GFP) regulated by the aggregation status of hIAPP, it was found that four intramolecular ligated hIAPP (4×hIAPP) could form obvious amyloids with mild toxicity. The validity and reliability of the screening tool were verified by testing six reported hIAPP inhibitors, including curcumin, epigallocatechin gallate and so on. Combined with surface plasmon resonance (SPR) and the screening tool, which could be a screening system for hIAPP inhibitors, we found that crocin specifically binds to hIAPP and acts inhibit amyloid formation of hIAPP. The effect of crocin was further confirmed by Thioflavin T (ThT) fluorescence and transmission electron microscopy (TEM) analysis. Thus, a screening system for hIAPP amyloid inhibitors and a new mechanism of crocin on anti‐T2D were obtained as a result of this study.

Human islet amyloid polypeptide: A therapeutic target for the management of type 2 diabetes mellitus

“…Several known antidiabetic molecules and other drugs have been evaluated for their anti-amyloidogenic potential. Table S1 [ [136] , [137] , [138] , [139] , [140] , [141] , [142] ] summarizes the results obtained by studies on drugs such as rifampicin, sitagliptin, metformin, and nonsteroidal anti-inflammatory drugs. Metformin, the most effective and commonly used drug till date for T2DM management [ 143 ], promotes the formation of the amyloid peptide associated with Alzheimer's disease [ 144 , 145 ].…”