Supplementation with γ-glutamylcysteine (γ-GC) lessens oxidative stress, brain inflammation and amyloid pathology and improves spatial memory in a murine model of AD.

Abstract

INTRODUCTION:

The accumulation of oxidative stress, neuroinflammation and abnormal aggregation of amyloid β-peptide (Aβ) have been shown to induce synaptic dysfunction and memory deficits in Alzheimer's disease (AD). Cellular depletion of the major endogenous antioxidant Glutathione (GSH) has been linked to cognitive decline and the development of AD pathology. Supplementation with γ-glutamylcysteine (γ-GC), the immediate precursor and the limiting substrate for GSH biosynthesis, can transiently augment cellular GSH levels by bypassing the regulation of GSH homeostasis.

METHODS:

In the present study, we investigated the effect of dietary supplementation of γ-GC on oxidative stress and Aβ pathology in the brains of APP/PS1 mice. The APP/PS1 mice were fed γ-GC from 3 months of age with biomarkers of apoptosis and cell death, oxidative stress, neuroinflammation and Aβ load being assessed at 6 months of age.

RESULTS:

Our data showed that supplementation with γ-GC lowered the levels of brain lipid peroxidation, protein carbonyls and apoptosis, increased both total GSH and the glutathione/glutathione disulphide (GSH/GSSG) ratio and replenished ATP and the activities of the antioxidant enzymes (superoxide dismutase (SOD), catalase, glutamine synthetase and glutathione peroxidase (GPX)), the latter being a key regulator of ferroptosis. Brain Aβ load was lower and acetylcholinesterase (AChE) activity was markedly improved compared to APP/PS1 mice fed a standard chow diet. Alteration in brain cytokine levels and matrix metalloproteinase enzymes MMP-2 and MMP-9 suggested that γ-GC may lower inflammation and enhance Aβ plaque clearance in vivo. Spatial memory was also improved by γ-GC as determined using the Morris water maze.

CONCLUSION:

Our data collectively suggested that supplementation with γ-GC may represent a novel strategy for the treatment and/or prevention of cognitive impairment and neurodegeneration.

• Authors: Yue Liu, Zheng Chen, Ben Li, Hua Yao, Martin Zarka, Jeffrey Welch, Perminder Sachdev, Wallace Bridge, Nady Braidy
• Journal: Neurochemistry international (Neurochem Int) Vol. 144 Pg. 104931 (03 2021) ISSN: 1872-9754 [Electronic] England
• PMID: 33276023 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Crown Copyright © 2020. Published by Elsevier Ltd. All rights reserved.

Chemical References

• Amyloid
• Dipeptides
• gamma-glutamylcysteine

Topics

• Alzheimer Disease (drug therapy, metabolism, pathology)
• Amyloid (antagonists & inhibitors, metabolism)
• Animals
• Dietary Supplements
• Dipeptides (administration & dosage)
• Disease Models, Animal
• Encephalitis (drug therapy, metabolism, pathology)
• Male
• Mice
• Mice, Transgenic
• Oxidative Stress (drug effects, physiology)
• Spatial Memory (drug effects, physiology)