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Updated: Apr 19, 2026
Saccharomyces cerevisiae Models of Alzheimer's Disease to Screen Genes, Mutations, and Chemicals Affecting Amyloid Beta Production by γ-Secretase
Published on: June 24, 2025
Pretreatment of chemically-synthesized Aβ42 affects its biological activity in yeast
Afsaneh Porzoor1, Joanne M Caine, Ian G Macreadie
1a School of Applied Sciences; Biosciences ; RMIT University ; Bundoora , Victoria , Australia.
Abstract:
The tendency of amyloid β (Aβ42) peptide to misfold and aggregate into insoluble amyloid fibrils in Alzheimer's disease (AD) has been well documented. Accumulation of Aβ42 fibrils has been correlated with abnormal apoptosis and unscheduled cell division which can also trigger the death of neuronal cells, while oligomers can also exhibit similar activities. While investigations using chemically-synthesized Aβ42 peptide have become common practice, there appear to be differences in outcomes from different preparations. In order to resolve this inconsistency, we report 2 separate methods of preparing chemically-synthesized Aβ42 and we examined their effects in yeast. Hexafluoroisopropanol pretreatment caused toxicity while, ammonium hydroxide treated Aβ42 induced cell proliferation in both C. glabrata and S. cerevisiae. The hexafluoroisopropanol prepared Aβ42 had greater tendency to form amyloid on yeast cells as determined by thioflavin T staining followed by flow cytometry and microscopy. Both quiescent and non-quiescent cells were analyzed by these methods of peptide preparation. Non-quiescent cells were susceptible to the toxicity of Aβ42 compared with quiescent cells (p < 0.005). These data explain the discrepancy in the previous publications about the effects of chemically-synthesized Aβ42 on yeast cells. The effect of Aβ42 on yeast cells was independent of the size of the peptide aggregates. However, the Aβ42 pretreatment determined whether the molecular conformation of peptide resulted in proliferation or toxicity in yeast based assays.
Insights
Chemically synthesized amyloid beta (Aβ42) peptide preparation methods influence its effects on yeast cells. Different pretreatments result in either toxicity or cell proliferation, clarifying previous research discrepancies.
Area of Science:
- Biochemistry
- Cell Biology
- Neuroscience
Background:
- Amyloid beta (Aβ42) peptide misfolding and aggregation are hallmarks of Alzheimer's disease (AD).
- Chemically synthesized Aβ42 preparations show inconsistent effects in research.
- Aβ42 oligomers and fibrils are implicated in neuronal cell death via apoptosis and abnormal cell division.
Purpose of the Study:
- To investigate the impact of different chemical synthesis preparation methods on Aβ42 effects in yeast.
- To resolve inconsistencies in previous studies regarding Aβ42's impact on yeast cells.
- To determine if Aβ42 aggregate size or molecular conformation influences its effects.
Main Methods:
- Two distinct methods for preparing chemically synthesized Aβ42 were employed.
- Effects of Aβ42 preparations were assessed in Saccharomyces cerevisiae and Candida glabrata yeast models.
- Thioflavin T staining, flow cytometry, and microscopy were used to analyze amyloid formation.
- Quiescent and non-quiescent yeast cells were analyzed for differential susceptibility.
Main Results:
- Hexafluoroisopropanol (HFIP) pretreatment of Aβ42 induced toxicity in yeast.
- Ammonium hydroxide (AH) treated Aβ42 promoted cell proliferation in both yeast species.
- HFIP-prepared Aβ42 exhibited a higher propensity for amyloid formation on yeast cells.
- Non-quiescent cells were significantly more susceptible to Aβ42 toxicity than quiescent cells (p < 0.005).
- Aβ42 aggregate size did not determine its effect; peptide pretreatment and molecular conformation were key.
Conclusions:
- The preparation method of chemically synthesized Aβ42 dictates its biological activity, causing either toxicity or proliferation in yeast.
- These findings reconcile discrepancies in prior research on Aβ42's effects on yeast.
- Molecular conformation, influenced by pretreatment, is critical for Aβ42's impact on yeast cell fate, independent of aggregate size.
