Dietary Sargassum fusiforme improves memory and reduces amyloid plaque load in an Alzheimer's disease mouse model

Jeroen Bogie, Cindy Hoeks, Melissa Schepers, Assia Tiane, Ann Cuypers, Frank Leijten, Yupyn Chintapakorn, Thiti Suttiyut, Surachai Pornpakakul, Dicky Struik, Anja Kerksiek, Hong-Bing Liu, Niels Hellings, Pilar Martinez-Martinez, Johan W. Jonker, Ilse Dewachter, Eric Sijbrands, Jochen Walter, Jerome Hendriks, Albert GroenBart Staels, Dieter Luetjohann, Tim Vanmierlo*, Monique Mulder

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

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Abstract

Activation of liver X receptors (LXRs) by synthetic agonists was found to improve cognition in Alzheimer's disease (AD) mice. However, these LXR agonists induce hypertriglyceridemia and hepatic steatosis, hampering their use in the clinic. We hypothesized that phytosterols as LXR agonists enhance cognition in AD without affecting plasma and hepatic triglycerides. Phytosterols previously reported to activate LXRs were tested in a luciferase-based LXR reporter assay. Using this assay, we found that phytosterols commonly present in a Western type diet in physiological concentrations do not activate LXRs. However, a lipid extract of the 24(S)-Saringosterol-containing seaweed Sargassum fusiforme did potently activate LXR beta. Dietary supplementation of crude Sargassum fusiforme or a Sargassum fusiforme-derived lipid extract to AD mice significantly improved short-term memory and reduced hippocampal A beta plaque load by 81%. Notably, none of the side effects typically induced by full synthetic LXR agonists were observed. In contrast, administration of the synthetic LXRa activator, AZ876, did not improve cognition and resulted in the accumulation of lipid droplets in the liver. Administration of Sargassum fusiforme-derived 24(S)-Saringosterol to cultured neurons reduced the secretion of A beta 42. Moreover, conditioned medium from 24(S)-Saringosterol-treated astrocytes added to microglia increased phagocytosis of A beta. Our data show that Sargassum fusiforme improves cognition and alleviates AD pathology. This may be explained at least partly by 24(S)-Saringosterol-mediated LXR beta activation.

Original languageEnglish
Article number4908
Number of pages16
JournalScientific Reports
Volume9
Issue number1
DOIs
Publication statusPublished - 20-Mar-2019

Keywords

  • LIVER-X RECEPTORS
  • LXR AGONIST TO901317
  • HUMAN SERUM-ALBUMIN
  • PLANT STEROLS
  • CHOLESTEROL HOMEOSTASIS
  • BETA-SITOSTEROL
  • BRAIN
  • MICE
  • METABOLISM
  • ACTIVATION

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