Profiling the Serum Protein Corona of Fibrillar Human Islet Amyloid Polypeptide.

Amyloids may be regarded as native nanomaterials that form in the presence of complex protein mixtures. By drawing an analogy with the physicochemical properties of nanoparticles in biological fluids, we hypothesized that amyloids should form a protein corona in vivo that would imbue the underlying amyloid with a modified biological identity. To explore this hypothesis, we characterized the protein corona of human islet amyloid polypeptide (IAPP) fibrils in fetal bovine serum using two complementary methodologies developed herein: quartz crystal microbalance and "centrifugal capture", coupled with nanoliquid chromatography tandem mass spectroscopy. Clear evidence for a significant protein corona was obtained. No trends were identified for amyloid corona proteins based on their physicochemical properties, whereas strong binding with IAPP fibrils occurred for linear proteins or multidomain proteins with structural plasticity. Proteomic analysis identified amyloid-enriched proteins that are known to play significant roles in mediating cellular machinery and processing, potentially leading to pathological outcomes and therapeutic targets.