Topical Area: Aging and Chronic Disease, Nutrition Translation. Nutrient-Gene Interactions, Carotenoids and Retinoids (CARIG)
Objectives : Moderate dietary methionine restriction (MR) extends life span in various animal models and delays the onset of aging-associated pathologies. However, the neuroprotective effects and underlying mechanism of MR on age and age-related diseases still remain to be investigated. Notably, fibroblast growth factor-21 (FGF21), a MR responding hormone mostly generated from liver, plays a critical role in neuronal mitochondrial function. Here, we aimed to reveal the neuroprotective effects of MR and the mediating role of FGF21 in aging mice model.
Methods : Male C57BL/6 mice (2-, 12-, and 15- month-old) were treated with control methionine diet (0.86% methionine) and methionine restriction diet (0.17% methionine) for 3 months. Adeno-associated virus was employed to build FGF21 knockdown mice model. Behavioral tests, synapse ultrastructure detection, and amino acid metabolomics were performed to evaluate cognitive function, neuron damage and signaling pathway activation.
Results : In behavioral tests, we found that MR significantly improved aging-induced decreased in spatial memory and cognitive function. Meanwhile, MR ameliorated neuronal damage and synapses structure damages in aging mice hippocampus. Moreover, MR significantly improved the mRNA expression of mitochondrial biogenesis and dynamics related genes such as COX2/fis1/pink1/binp1/drp1 in aging mice brain. MR also altered plasma amino acid metabolic phenotype-related glutathione synthesis, energy metabolism, and nervous system function. Furthermore, we found that MR could significant increase FGF21 level in both liver and serum of aging mice. Knockdown of FGF21 dramatically diminished the benefits of MR on cognitive impairments.
Conclusions : These results showed that MR mitigated aging-induced memory impairment and synapses structure damages via activating FGF21 signaling pathway. The study suggest that this dietary restriction might be plausible therapeutic intervention for aging and other neurodegenerative diseases such AD and PD.
Funding Sources : This work was financially supported by the National Key Research and Development Program of China, National Natural Science Foundation of China.