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Kun Judit

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Moussong Éva
How nanoparticles affect aggregation and cytotoxicity of the amyloid-beta peptide?

Aug 29 - kedd

15:30 – 17:00

I. Poszterszekció

P18

How nanoparticles affect aggregation and cytotoxicity of the amyloid-beta peptide?

Éva Moussong1, Márton Péter Nyiri1, Nikoletta Murvai1, Judit Kun1,2, Attila Kovács1,2, Tamás Molnár1, András Micsonai1,2, József Kardos1,2

1Department of Biochemistry, Institute of Biology, ELTE Eötvös Loránd University, Budapest H-1117, Hungary

2ELTE NAP Neuroimmunology Research Group, Department of Biochemistry, Institute of Biology, ELTE Eötvös Loránd University, Budapest H-1117, Hungary

Using nanoparticles is becoming common in medicine and biotechnology. Additionally, nanoparticles are also present in our environment as nano-pollution which might enter living organisms. Proteins which get into contact with nanoparticles, might undergo structural changes. Aggregation and amyloid formation of proteins and peptides can also be affected by nanoparticles. Our group is interested in investigating the aggregation and amyloid formation of the amyloid-beta (Aβ) peptide which is known for creating amyloid fibrils in the brain in Alzheimer’s disease. We used in-house expressed recombinant Aβ(1-42) to study the structure, aggregation kinetics, and cytotoxicity of the peptide. We characterized nanoparticles of different materials (CaF2, silica, polystyrene) and studied their effects on Aβ. Based on thioflavin T fluorescence, we found that nanoparticles typically reduce lag time of the aggregation. Polystyrene nanoparticles bind peptide monomers up to a saturation point and let only excess peptides to form fibrils. CaF2 and silica do not show an effect similar to this, but they influence the secondary structure of the fibrils. We used circular dichroism (CD) spectroscopy and the BeStSel method to determine secondary structure composition. Aβ fibrils formed alone have a high content of parallel β-sheets. Nanoparticles, depending on their type, affect the secondary structure composition of Aβ aggregates altering the fractions of the different type of β-sheet structures. Toxicity measurements on mouse hippocampal cells suggest that Aβ is highly cytotoxic, but nanoparticles might reduce cytotoxicity of Aβ if applied in appropriate concentrations.

Acknowledgement

This work was supported by the National Research, Development and Innovation Office of Hungary (grants PD135510, K138937, 2019-2.1.6-NEMZ_KI-2019-00012, and 2019-2.1.11-TÉT-2020-00101), the National Brain Research Program NAP 3.0 of the Hungarian Academy of Sciences (NAP2022-I-3/2022), and the Gedeon Richter Talentum Foundation (grant ’Richter Gedeon Kiválósági PhD Ösztöndíj’).