Influence of Cortisol on the Fibril Formation Kinetics of Aβ42 Peptide: A Multi-Technical Approach.

Alessandro Nucara, Francesca Ripanti, Simona Sennato, Giacomo Nisini, Emiliano De Santis, Mahta Sefat, Marina Carbonaro, Dalila Mango, Velia Minicozzi, Marilena Carbone

International journal of molecular sciences 2022 May 26

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Amyloid-β peptide (Aβ) aggregates are known to be correlated with pathological neurodegenerative diseases. The fibril formation process of such peptides in solution is influenced by several factors, such as the ionic strength of the buffer, concentration, pH, and presence of other molecules, just to mention a few. In this paper, we report a detailed analysis of in vitro Aβ42 fibril formation in the presence of cortisol at different relative concentrations. The thioflavin T fluorescence assay allowed us to monitor the fibril formation kinetics, while a morphological characterization of the aggregates was obtained by atomic force microscopy. Moreover, infrared absorption spectroscopy was exploited to investigate the secondary structure changes along the fibril formation path. Molecular dynamics calculations allowed us to understand the intermolecular interactions with cortisol. The combined results demonstrated the influence of cortisol on the fibril formation process: indeed, at cortisol-Aβ42 concentration ratio (ρ) close to 0.1 a faster organization of Aβ42 fragments into fibrils is promoted, while for ρ = 1 the formation of fibrils is completely inhibited.

Citation

Alessandro Nucara, Francesca Ripanti, Simona Sennato, Giacomo Nisini, Emiliano De Santis, Mahta Sefat, Marina Carbonaro, Dalila Mango, Velia Minicozzi, Marilena Carbone. Influence of Cortisol on the Fibril Formation Kinetics of Aβ42 Peptide: A Multi-Technical Approach. International journal of molecular sciences. 2022 May 26;23(11)