Oxysterols and Oxysterol Sulfates in Alzheimer's Disease Brain and Cerebrospinal Fluid

Dias, Irundika H.K.; Shokr, Hala; Shephard, Freya; Chakrabarti, Lisa

Abstract

Background: Brain cholesterol levels are tightly regulated but increasing evidence indicates that cholesterol metabolism may drive Alzheimer's disease (AD)-associated pathological changes. Recent advances in understanding of mitochondrial dysfunction in AD brain have presented a vital role played by mitochondria in oxysterol biosynthesis and their involvement in pathophysiology. Oxysterol accumulation in brain is controlled by various enzymatic pathways including sulfation. While research into oxysterol is under the areas of active investigation, there is less evidence for oxysterol sulfate levels in human brain. Objective: This study investigates the hypothesis that AD brain oxysterol detoxification via sulfation is impaired in later stages of disease resulting in oxysterol accumulation. Methods: Lipids were extracted from postmortem frozen brain tissue and cerebrospinal (CSF) from late- (Braak stage III-IV) and early- (Braak stage I-II) stage AD patients. Samples were spiked with internal standards prior to lipid extraction. Oxysterols were enriched with a two-step solid phase extraction using a polymeric SPE column and further separation was achieved by LC-MS/MS. Results: Oxysterols, 26-hydroxycholesterol (26-OHC), 25-hydroxycholesterol (25-OHC), and 7-oxycholesterol levels were higher in brain tissue and mitochondria extracted from late-stage AD brain tissue except for 24S-hydroxycholesterol, which was decreased in late AD. However, oxysterol sulfates are significantly lower in the AD frontal cortex. Oxysterols, 25-OHC, and 7-oxocholesterol was higher is CSF but 26-OHC and oxysterol sulfate levels were not changed. Conclusion: Our results show oxysterol metabolism is altered in AD brain mitochondria, favoring synthesis of 26-OHC, 25-OHC, and 7-oxocholesterol, and this may influence brain mitochondrial function and acceleration of the disease.

Citation

Dias, I. H., Shokr, H., Shephard, F., & Chakrabarti, L. (2022). Oxysterols and Oxysterol Sulfates in Alzheimer's Disease Brain and Cerebrospinal Fluid. Journal of Alzheimer's Disease, 87(4), 1527-1536. https://doi.org/10.3233/JAD-220083

• Journal Article Type: Article
• Acceptance Date: Mar 30, 2022
• Online Publication Date: Apr 27, 2022
• Publication Date: Jun 14, 2022
• Deposit Date: Mar 21, 2025
• Publicly Available Date: Mar 21, 2025
• Journal: Journal of Alzheimer's Disease
• Print ISSN: 1387-2877
• Electronic ISSN: 1875-8908
• Publisher: IOS Press
• Peer Reviewed: Peer Reviewed
• Volume: 87
• Issue: 4
• Pages: 1527-1536
• DOI: https://doi.org/10.3233/JAD-220083
• Keywords: Alzheimer’s disease, brain, cholesterol, mitochondria, oxidative stress, oxysterols
• Public URL: https://nottingham-repository.worktribe.com/output/24425939
• Publisher URL: https://journals.sagepub.com/doi/full/10.3233/JAD-220083