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When proteins get stuck at solid: unlocking the secrets to brain diseases

Nanoscale view of proteins opens window to treat neurodegenerative illness

Date:
August 24, 2023
Source:
University of Sydney
Summary:
Biomedical engineers have developed sophisticated optical techniques to monitor at close range the process by which protein aggregates form during liquid-to-liquid transition. This can lead to solid condensates which can trigger a process that forms neural plaques, that can cause Alzheimer's and other diseases.
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Many diseases affecting the brain and nervous system are linked to the formation of protein aggregates, or solid condensates, in cells from their liquid form condensate, but little is known about this process.

This liquid-to-solid transition can trigger the formation of what are called amyloid fibrils. These can further form plaques in neurons causing neurodegenerative diseases such as Alzheimer's.

Biomedical engineers at the University of Sydney, in collaboration with scientists at the University of Cambridge and Harvard University, have now developed sophisticated optical techniques to monitor at close range the process by which these protein aggregates form.

By testing a protein associated with Amyotrophic Lateral Sclerosis -- ALS disease, which affected astrophysicist Professor Stephen Hawking -- the Sydney engineers closely monitored the transition of this protein from its liquid to solid phase.

"This is a huge step forward to understanding how neurogenerative diseases develop from a fundamental perspective," said Dr Yi Shen, lead author of the research published in the Proceedings of the National Academy of Sciences (PNAS).

"We can now directly observe the transition of these critical proteins from liquid to solid at the nanoscale -- a millionth of a metre in scale," said Dr Daniele Vigolo, a senior lecturer in the School of Biomedical Engineering and a member of the University of Sydney Nano Institute.

Proteins regularly form condensates during liquid-to-liquid phase separation in a wide range of critical and healthy biological functions, such as the formation of human embryos. This process assists biochemical reactions where protein concentrations are critical and also promotes healthy protein-protein interactions.

"However, this process also increases the risk of dysfunctional aggregation, where unhealthy aggregates of solid proteins form in human cells," said Dr Shen, who is an ARC DECRA Fellow in the School of Chemical and Biomolecular Engineering and also a member of Sydney Nano.

"This can lead to aberrant structures associated with neurodegenerative diseases because the proteins no longer exhibit rapid reversibility back to liquid form. It is therefore crucial to monitor condensate dynamics, as they directly affect pathological states," she said.

The world-first nanoscale optical observation of this process has allowed the team to determine that the transition from liquid to solid protein starts at the interface of the protein condensates. This window onto the phase transition also revealed that the internal structures of these protein agglomerates are heterogenous, where previously they were thought to be homogeneous.

Dr Vigolo said: "Our findings promise to greatly improve our understanding of neurogenerative diseases from a fundamental perspective.

"This means a promising new area of research to better understand how Alzheimer's disease and ALS develops in the brain, affecting millions of people worldwide."


Story Source:

Materials provided by University of Sydney. Note: Content may be edited for style and length.


Journal Reference:

  1. Yi Shen, Anqi Chen, Wenyun Wang, Yinan Shen, Francesco Simone Ruggeri, Stefano Aime, Zizhao Wang, Seema Qamar, Jorge R. Espinosa, Adiran Garaizar, Peter St George-Hyslop, Rosana Collepardo-Guevara, David A. Weitz, Daniele Vigolo, Tuomas P. J. Knowles. The liquid-to-solid transition of FUS is promoted by the condensate surface. Proceedings of the National Academy of Sciences, 2023; 120 (33) DOI: 10.1073/pnas.2301366120

Cite This Page:

University of Sydney. "When proteins get stuck at solid: unlocking the secrets to brain diseases." ScienceDaily. ScienceDaily, 24 August 2023. <www.sciencedaily.com/releases/2023/08/230824003818.htm>.
University of Sydney. (2023, August 24). When proteins get stuck at solid: unlocking the secrets to brain diseases. ScienceDaily. Retrieved February 29, 2024 from www.sciencedaily.com/releases/2023/08/230824003818.htm
University of Sydney. "When proteins get stuck at solid: unlocking the secrets to brain diseases." ScienceDaily. www.sciencedaily.com/releases/2023/08/230824003818.htm (accessed February 29, 2024).

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