Impact of Hyperhomocysteinemia and Different Dietary Interventions on Cognitive Performance in a Knock-in Mouse Model for Alzheimer’s Disease

Background: Hyperhomocysteinemia is considered a possible contributor to the complex pathology of Alzheimer’s disease (AD). For years, researchers in this field have discussed the apparent detrimental effects of the endogenous amino acid homocysteine in the brain. In this study, the roles of hyperhomocysteinemia driven by vitamin B deficiency, as well as potentially beneficial dietary interventions, were investigated in the novel AppNL-G-F knock-in mouse model for AD, simulating an early stage of the disease. Methods: Urine and serum samples were analyzed using a validated LC-MS/MS method and the impact of different experimental diets on cognitive performance was studied in a comprehensive behavioral test battery. Finally, we analyzed brain samples immunohistochemically in order to assess amyloid-β (Aβ) plaque deposition. Results: Behavioral testing data indicated subtle cognitive deficits in AppNL-G-F compared to C57BL/6J wild type mice. Elevation of homocysteine and homocysteic acid, as well as counteracting dietary interventions, mostly did not result in significant effects on learning and memory performance, nor in a modified Aβ plaque deposition in 35-week-old AppNL-G-F mice. Conclusion: Despite prominent Aβ plaque deposition, the AppNL-G-F model merely displays a very mild AD-like phenotype at the investigated age. Older AppNL-G-F mice should be tested in order to further investigate potential effects of hyperhomocysteinemia and dietary interventions.

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P.759 Impact of hyperhomocysteinemia and different dietary interventions on cognitive performance in a knock-in mouse model for Alzheimer's disease

European Neuropsychopharmacology ◽

10.1016/j.euroneuro.2020.09.557 ◽

2020 ◽

Vol 40 ◽

pp. S429

Author(s):

H. Nieraad ◽

N. De Bruin ◽

O. Arne ◽

M.C.J. Hofmann ◽

M. Schmidt ◽

...

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Mouse Model ◽

Cognitive Performance ◽

Dietary Interventions

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Early Candidate Urine Biomarkers for Detecting Alzheimer’s Disease Before Amyloid-β Plaque Deposition in an APP (swe)/PSEN1dE9 Transgenic Mouse Model

Journal of Alzheimer s Disease ◽

10.3233/jad-180412 ◽

2018 ◽

Vol 66 (2) ◽

pp. 613-637 ◽

Cited By ~ 18

Author(s):

Fanshuang Zhang ◽

Jing Wei ◽

Xundou Li ◽

Chao Ma ◽

Youhe Gao

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Mouse Model ◽

Transgenic Mouse ◽

Amyloid Β ◽

Transgenic Mouse Model ◽

Plaque Deposition ◽

Urine Biomarkers

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Fluoxetine Protects against Dendritic Spine Loss in Middle-aged APPswe/PSEN1dE9 Double Transgenic Alzheimer’s Disease Mice

Current Alzheimer Research ◽

10.2174/1567205017666200213095419 ◽

2020 ◽

Vol 17 (1) ◽

pp. 93-103 ◽

Cited By ~ 1

Author(s):

Jing Ma ◽

Yuan Gao ◽

Wei Tang ◽

Wei Huang ◽

Yong Tang

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Dendritic Spines ◽

Dendritic Spine ◽

Early Stage ◽

Learning Ability ◽

Middle Aged ◽

Protein Levels ◽

Spine Pathology ◽

The Impact

Background: Studies have suggested that cognitive impairment in Alzheimer’s disease (AD) is associated with dendritic spine loss, especially in the hippocampus. Fluoxetine (FLX) has been shown to improve cognition in the early stage of AD and to be associated with diminishing synapse degeneration in the hippocampus. However, little is known about whether FLX affects the pathogenesis of AD in the middle-tolate stage and whether its effects are correlated with the amelioration of hippocampal dendritic dysfunction. Previously, it has been observed that FLX improves the spatial learning ability of middleaged APP/PS1 mice. Objective: In the present study, we further characterized the impact of FLX on dendritic spines in the hippocampus of middle-aged APP/PS1 mice. Results: It has been found that the numbers of dendritic spines in dentate gyrus (DG), CA1 and CA2/3 of hippocampus were significantly increased by FLX. Meanwhile, FLX effectively attenuated hyperphosphorylation of tau at Ser396 and elevated protein levels of postsynaptic density 95 (PSD-95) and synapsin-1 (SYN-1) in the hippocampus. Conclusion: These results indicated that the enhanced learning ability observed in FLX-treated middle-aged APP/PS1 mice might be associated with remarkable mitigation of hippocampal dendritic spine pathology by FLX and suggested that FLX might be explored as a new strategy for therapy of AD in the middle-to-late stage.

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High‐Fat Diet Modulates Hepatic Amyloid β and Cerebrosterol Metabolism in the Triple Transgenic Mouse Model of Alzheimer’s Disease

Hepatology Communications ◽

10.1002/hep4.1609 ◽

2020 ◽

Author(s):

Cristina R. Bosoi ◽

Milène Vandal ◽

Marine Tournissac ◽

Manon Leclerc ◽

Hortense Fanet ◽

...

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Mouse Model ◽

Transgenic Mouse ◽

High Fat Diet ◽

Amyloid Β ◽

Transgenic Mouse Model ◽

High Fat ◽

Model Of Alzheimer’S Disease ◽

Triple Transgenic Mouse

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24(S)-Saringosterol Prevents Cognitive Decline in a Mouse Model for Alzheimer’s Disease

Marine Drugs ◽

10.3390/md19040190 ◽

2021 ◽

Vol 19 (4) ◽

pp. 190

Author(s):

Nikita Martens ◽

Melissa Schepers ◽

Na Zhan ◽

Frank Leijten ◽

Gardi Voortman ◽

...

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Mouse Model ◽

Cognitive Decline ◽

Inflammatory Marker ◽

Amyloid Β ◽

Liver Fat ◽

Gas Chromatography Mass Spectrometry ◽

Memory Decline ◽

Plaque Load

We recently found that dietary supplementation with the seaweed Sargassum fusiforme, containing the preferential LXRβ-agonist 24(S)-saringosterol, prevented memory decline and reduced amyloid-β (Aβ) deposition in an Alzheimer’s disease (AD) mouse model without inducing hepatic steatosis. Here, we examined the effects of 24(S)-saringosterol as a food additive on cognition and neuropathology in AD mice. Six-month-old male APPswePS1ΔE9 mice and wildtype C57BL/6J littermates received 24(S)-saringosterol (0.5 mg/25 g body weight/day) (APPswePS1ΔE9 n = 20; C57BL/6J n = 19) or vehicle (APPswePS1ΔE9 n = 17; C57BL/6J n = 19) for 10 weeks. Cognition was assessed using object recognition and object location tasks. Sterols were analyzed by gas chromatography/mass spectrometry, Aβ and inflammatory markers by immunohistochemistry, and gene expression by quantitative real-time PCR. Hepatic lipids were quantified after Oil-Red-O staining. Administration of 24(S)-saringosterol prevented cognitive decline in APPswePS1ΔE9 mice without affecting the Aβ plaque load. Moreover, 24(S)-saringosterol prevented the increase in the inflammatory marker Iba1 in the cortex of APPswePS1ΔE9 mice (p < 0.001). Furthermore, 24(S)-saringosterol did not affect the expression of lipid metabolism-related LXR-response genes in the hippocampus nor the hepatic neutral lipid content. Thus, administration of 24(S)-saringosterol prevented cognitive decline in APPswePS1ΔE9 mice independent of effects on Aβ load and without adverse effects on liver fat content. The anti-inflammatory effects of 24(S)-saringosterol may contribute to the prevention of cognitive decline.

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Impaired spike-gamma coupling of area CA3 fast-spiking interneurons as the earliest functional impairment in the AppNL-G-F mouse model of Alzheimer’s disease

Molecular Psychiatry ◽

10.1038/s41380-021-01257-0 ◽

2021 ◽

Author(s):

Luis Enrique Arroyo-García ◽

Arturo G. Isla ◽

Yuniesky Andrade-Talavera ◽

Hugo Balleza-Tapia ◽

Raúl Loera-Valencia ◽

...

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Cognitive Impairment ◽

Mouse Model ◽

Functional Impairment ◽

Amyloid Β ◽

Gamma Oscillations ◽

Gamma Oscillation ◽

Gamma Rhythm ◽

Fast Spiking

AbstractIn Alzheimer’s disease (AD) the accumulation of amyloid-β (Aβ) correlates with degradation of cognition-relevant gamma oscillations. The gamma rhythm relies on proper neuronal spike-gamma coupling, specifically of fast-spiking interneurons (FSN). Here we tested the hypothesis that decrease in gamma power and FSN synchrony precede amyloid plaque deposition and cognitive impairment in AppNL-G-F knock-in mice (AppNL-G-F). The aim of the study was to evaluate the amyloidogenic pathology progression in the novel AppNL-G-F mouse model using in vitro electrophysiological network analysis. Using patch clamp of FSNs and pyramidal cells (PCs) with simultaneous gamma oscillation recordings, we compared the activity of the hippocampal network of wild-type mice (WT) and the AppNL-G-F mice at four disease stages (1, 2, 4, and 6 months of age). We found a severe degradation of gamma oscillation power that is independent of, and precedes Aβ plaque formation, and the cognitive impairment reported previously in this animal model. The degradation correlates with increased Aβ1-42 concentration in the brain. Analysis on the cellular level showed an impaired spike-gamma coupling of FSN from 2 months of age that correlates with the degradation of gamma oscillations. From 6 months of age PC firing becomes desynchronized also, correlating with reports in the literature of robust Aβ plaque pathology and cognitive impairment in the AppNL-G-F mice. This study provides evidence that impaired FSN spike-gamma coupling is one of the earliest functional impairment caused by the amyloidogenic pathology progression likely is the main cause for the degradation of gamma oscillations and consequent cognitive impairment. Our data suggests that therapeutic approaches should be aimed at restoring normal FSN spike-gamma coupling and not just removal of Aβ.

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Shotgun lipidomics of liver and brain tissue of Alzheimer’s disease model mice treated with acitretin

Scientific Reports ◽

10.1038/s41598-021-94706-3 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Anna A. Lauer ◽

Daniel Janitschke ◽

Malena dos Santos Guilherme ◽

Vu Thu Thuy Nguyen ◽

Cornel M. Bachmann ◽

...

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Neurodegenerative Disorder ◽

Amyloid Β ◽

Lipid Homeostasis ◽

Medical Surveillance ◽

Shotgun Lipidomics ◽

App Processing ◽

Cognitive Improvement ◽

The Impact

AbstractAlzheimer’s disease (AD) is a very frequent neurodegenerative disorder characterized by an accumulation of amyloid-β (Aβ). Acitretin, a retinoid-derivative and approved treatment for Psoriasis vulgaris, increases non-amyloidogenic Amyloid-Precursor-Protein-(APP)-processing, prevents Aβ-production and elicits cognitive improvement in AD mouse models. As an unintended side effect, acitretin could result in hyperlipidemia. Here, we analyzed the impact of acitretin on the lipidome in brain and liver tissue in the 5xFAD mouse-model. In line with literature, triglycerides were increased in liver accompanied by increased PCaa, plasmalogens and acyl-carnitines, whereas SM-species were decreased. In brain, these effects were partially enhanced or similar but also inverted. While for SM and plasmalogens similar effects were found, PCaa, TAG and acyl-carnitines showed an inverse effect in both tissues. Our findings emphasize, that potential pharmaceuticals to treat AD should be carefully monitored with respect to lipid-homeostasis because APP-processing itself modulates lipid-metabolism and medication might result in further and unexpected changes. Moreover, deducing effects of brain lipid-homeostasis from results obtained for other tissues should be considered cautiously. With respect to acitretin, the increase in brain plasmalogens might display a further positive probability in AD-treatment, while other results, such as decreased SM, indicate the need of medical surveillance for treated patients.

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