Nanoparticles With a Specific Size and Surface Charge Promote Disruption of the Secondary Structure and Amyloid-Like Fibrillation of Human Insulin Under Physiological Conditions

Abstract

Nanoparticles attract much interest as fluorescent labels for diagnostic and therapeutic tools, although their applications are often hindered by size- and shape-dependent cytotoxicity. This cytotoxicity is related not only to the leak of toxic metals from nanoparticles into a biological solution, but also to molecular cytotoxicity effects determined by the formation of a protein corona, appearance of an altered protein conformation leading to exposure of cryptic epitopes and cooperative effects involved in the interaction of proteins and peptides with nanoparticles. In the last case, nanoparticles may serve, depending on their nature, as centers of self-association or fibrillation of proteins and peptides, provoking amyloid-like proteinopathies, or as inhibitors of self-association of proteins, or they can self-assemble on biopolymers as on templates. In this study, human insulin protein was used to analyze nanoparticle-induced proteinopathy in physiological conditions. It is known that human insulin may form amyloid fibers, but only under extreme experimental conditions (very low pH and high temperatures). Here, we have shown that the quantum dots (QDs) may induce amyloid-like fibrillation of human insulin under physiological conditions through a complex process strongly dependent on the size and surface charge of QDs. The insulin molecular structure and fibril morphology have been shown to be modified at different stages of its fibrillation, which has been proved by comparative analysis of the data obtained using circular dichroism, dynamic light scattering, amyloid-specific thioflavin T (ThT) assay, transmission electron microscopy, and high-speed atomic force microscopy. We have found important roles of the QD size and surface charge in the destabilization of the insulin structure and the subsequent fibrillation. Remodeling of the insulin secondary structure accompanied by remarkable increase in the rate of formation of amyloid-like fibrils under physiologically normal conditions was observed when the protein was incubated with QDs of exact specific diameter coated with slightly negative specific polyethylene glycol (PEG) derivatives. Strongly negatively or slightly positively charged PEG-modified QDs of the same specific diameter or QDs of bigger or smaller diameters had no effect on insulin fibrillation. The observed effects pave the way to the control of amyloidosis proteinopathy by varying the nanoparticle size and surface charge.

<p>Protein–Nanoparticle Interaction: Corona Formation and Conformational Changes in Proteins on Nanoparticles</p>

“…A recent study highlighted that quantum dots composed of CdSe/ZnS could disrupt the secondary structure of insulin and induce aggregation and fibrillation, depending on the specific size and surface charge of NPs. 32 To overcome the potential problems of NP application, recent studies have focused on how the protein corona can be used to produce beneficial effects in vivo. Pre-incubation or artificial coating of NPs with a corona protein can enhance the NPs function.…”

Identification of new dermaseptins with self-assembly tendency: membrane disruption, biofilm eradication, and infected wound healing efficacy

“…Therefore, the antimicrobial effect of DMS-PS2 in solution was predicted as a dynamically changing process, ranging from unimolecular to oligomerization, in order to associate with the sustained and potent antimicrobial effects. The process of peptide self-assembly into amyloid-like fibrils is a two-step process, that is, from single peptide molecule to small amyloid oligomers and from the developed oligomers to assembled fibrils 37 . Apparently, our DMS-PS2 formed small-sized aggregates with oligomerization at the tested condition, indicating that the persistent aggregation might play a part in killing the bacterial cells or penetrating the bacterial biofilms.…”

Amyloid‐Mediated Fabrication of Organic–Inorganic Hybrid Materials and Their Biomedical Applications

“…[48,49] In some cases, the presence of nanoparticles could promote aggregation of Aβ, which was explained in terms of a condensationordering mechanism. [50][51][52] Since the fibrillation occurs by nucleation-dependent kinetics, the increased local concentration of peptides around nanoparticles greatly accelerates the fibril formation. [48] On the contrary, in other case, the significant inhibition of Aβ amyloid polymerization was observed for single-walled carbon nanotubes (SWCNTs) because of a strong binding or a large particle/peptide interaction surface area.…”