Amyloid Structural Changes Studied by Infrared Microspectroscopy in Bigenic Cellular Models of Alzheimer’s Disease

• Main Authors: Agnes Paulus, Anders Engdahl, Yiyi Yang, Antonio Boza-Serrano, Sara Bachiller, Laura Torres-Garcia, Alexander Svanbergsson, Megg G. Garcia, Gunnar K. Gouras, Jia-Yi Li, Tomas Deierborg, Oxana Klementieva
• Format: Article
• Language: English
• Published: MDPI AG 2021-03-01
• Series: International Journal of Molecular Sciences
• Subjects: FTIR; amyloid-β; Tau; α-synuclein β-sheet; cellular environment; Alzheimer’s disease
• Online Access: https://www.mdpi.com/1422-0067/22/7/3430

Alzheimer’s disease affects millions of lives worldwide. This terminal disease is characterized by the formation of amyloid aggregates, so-called amyloid oligomers. These oligomers are composed of β-sheet structures, which are believed to be neurotoxic. However, the actual secondary structure that contributes most to neurotoxicity remains unknown. This lack of knowledge is due to the challenging nature of characterizing the secondary structure of amyloids in cells. To overcome this and investigate the molecular changes in proteins directly in cells, we used synchrotron-based infrared microspectroscopy, a label-free and non-destructive technique available for in situ molecular imaging, to detect structural changes in proteins and lipids. Specifically, we evaluated the formation of β-sheet structures in different monogenic and bigenic cellular models of Alzheimer’s disease that we generated for this study. We report on the possibility to discern different amyloid signatures directly in cells using infrared microspectroscopy and demonstrate that bigenic (amyloid-β, α-synuclein) and (amyloid-β, Tau) neuron-like cells display changes in β-sheet load. Altogether, our findings support the notion that different molecular mechanisms of amyloid aggregation, as opposed to a common mechanism, are triggered by the specific cellular environment and, therefore, that various mechanisms lead to the development of Alzheimer’s disease.