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Radkohl A, Schusterbauer V, Bernauer L, Rechberger GN, Wolinski H, Schittmayer M, Birner-Gruenberger R, Thallinger GG, Leitner E, Baeck M, Pichler H, Emmerstorfer-Augustin A. Human Sterols Are Overproduced, Stored and Excreted in Yeasts. Int J Mol Sci 2024; 25:781. [PMID: 38255855 PMCID: PMC10815178 DOI: 10.3390/ijms25020781] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Revised: 12/27/2023] [Accepted: 12/29/2023] [Indexed: 01/24/2024] Open
Abstract
Sterols exert a profound influence on numerous cellular processes, playing a crucial role in both health and disease. However, comprehending the effects of sterol dysfunction on cellular physiology is challenging. Consequently, numerous processes affected by impaired sterol biosynthesis still elude our complete understanding. In this study, we made use of yeast strains that produce cholesterol instead of ergosterol and investigated the cellular response mechanisms on the transcriptome as well as the lipid level. The exchange of ergosterol for cholesterol caused the downregulation of phosphatidylethanolamine and phosphatidylserine and upregulation of phosphatidylinositol and phosphatidylcholine biosynthesis. Additionally, a shift towards polyunsaturated fatty acids was observed. While the sphingolipid levels dropped, the total amounts of sterols and triacylglycerol increased, which resulted in 1.7-fold enlarged lipid droplets in cholesterol-producing yeast cells. In addition to internal storage, cholesterol and its precursors were excreted into the culture supernatant, most likely by the action of ABC transporters Snq2, Pdr12 and Pdr15. Overall, our results demonstrate that, similarly to mammalian cells, the production of non-native sterols and sterol precursors causes lipotoxicity in K. phaffii, mainly due to upregulated sterol biosynthesis, and they highlight the different survival and stress response mechanisms on multiple, integrative levels.
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Affiliation(s)
- Astrid Radkohl
- Institute of Molecular Biotechnology, Graz University of Technology, NAWI Graz, 8010 Graz, Austria
- BioTechMed-Graz, 8010 Graz, Austria
| | - Veronika Schusterbauer
- Bisy GmbH, 8200 Hofstaetten an der Raab, Austria
- Institute of Biomedical Informatics, Graz University of Technology, 8010 Graz, Austria
| | - Lukas Bernauer
- Institute of Molecular Biotechnology, Graz University of Technology, NAWI Graz, 8010 Graz, Austria
- BioTechMed-Graz, 8010 Graz, Austria
| | - Gerald N. Rechberger
- Department of Molecular Biosciences, University of Graz, NAWI Graz, 8010 Graz, Austria
| | - Heimo Wolinski
- Department of Molecular Biosciences, University of Graz, NAWI Graz, 8010 Graz, Austria
- Field of Excellence BioHealth, University of Graz, 8010 Graz, Austria
| | - Matthias Schittmayer
- Institute of Chemical Technologies and Analytics, Technische Universität Wien, 1040 Vienna, Austria (R.B.-G.)
| | - Ruth Birner-Gruenberger
- Institute of Chemical Technologies and Analytics, Technische Universität Wien, 1040 Vienna, Austria (R.B.-G.)
| | - Gerhard G. Thallinger
- Institute of Biomedical Informatics, Graz University of Technology, 8010 Graz, Austria
| | - Erich Leitner
- Institute of Analytical Chemistry and Food Chemistry, University of Graz, NAWI Graz, 8010 Graz, Austria;
| | - Melanie Baeck
- Institute of Molecular Biotechnology, Graz University of Technology, NAWI Graz, 8010 Graz, Austria
| | - Harald Pichler
- Institute of Molecular Biotechnology, Graz University of Technology, NAWI Graz, 8010 Graz, Austria
- BioTechMed-Graz, 8010 Graz, Austria
- Acib—Austrian Centre of Industrial Biotechnology, 8010 Graz, Austria
| | - Anita Emmerstorfer-Augustin
- Institute of Molecular Biotechnology, Graz University of Technology, NAWI Graz, 8010 Graz, Austria
- BioTechMed-Graz, 8010 Graz, Austria
- Acib—Austrian Centre of Industrial Biotechnology, 8010 Graz, Austria
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