Cattle Encephalon Glycoside and Ignotin Ameliorate Palmitoylation of PSD-95 and Enhance Expression of Synaptic Proteins in the Frontal Cortex of a APPswe/PS1dE9 Mouse Model of Alzheimer’s Disease

Mitophagy activation by rapamycin enhances mitochondrial function and cognition in 5×FAD mice

Alzheimer's disease (AD) is the most prevalent form of dementia, characterized by severe mitochondrial dysfunction, which is an intracellular process that is significantly compromised in the early stages of AD. Mitophagy, the selective removal of damaged mitochondria, is a potential therapeutic strategy for AD. Rapamycin, a mammalian target of rapamycin (mTOR) inhibitor, augmented autophagy and mitigated cognitive impairment. Our study revealed that rapamycin enhances cognitive function by activating mitophagy, alleviating neuronal loss, and improving mitochondrial dysfunction in 5 ×FAD mice. Interestingly, the neuroprotective effect of rapamycin in AD were negated by treatment with 3-MA, a mitophagy inhibitor. Overall, our findings suggest that rapamycin ameliorates cognitive impairment in 5 ×FAD mice via mitophagy activation and its downstream PINK1-Parkin pathway, which aids in the clearance of amyloid-β (Aβ) and damaged mitochondria. This study reveals a novel mechanism involving mitophagy regulation underlying the therapeutic effect of rapamycin in AD. This study provides new insights and therapeutic targets for rapamycin in the treatment of AD. However, there are still some shortcomings in this topic; if we can further knock out the PINK1/Parkin gene in animals or use siRNA technology, we can further confirm the experimental results.

Leonurine Alleviates Cognitive Dysfunction and Reduces Oxidative Stress by Activating Nrf-2 Pathway in Alzheimer's Disease Mouse Model

Introduction

Alzheimer's disease (AD) is the most common type of dementia, impacting approximately 50 million individuals globally. However, the current treatments available for AD are only symptomatic and have limited efficacy. This study aimed to investigate whether Leonurine could alleviate cognitive dysfunction in a mouse model of AD and explore its underlying molecular mechanisms.

Methods

In this study, male APP/PS1 mice were orally administered Leonurine for two consecutive months. The cognitive functions of the mice were then evaluated using novel object recognition (NOR) and Morris water maze (MWM) tests. Hippocampal neuronal damage was observed through Nissl staining, Aβ levels were determined through ELISA, oxidative stress activity was detected through biochemical methods, and the nuclear factor erythroid-2-related factor 2 (Nrf-2) pathway was analyzed using western blot and real-time quantitative polymerase chain reaction analysis.

Results

Our results demonstrated that Leonurine treatment markedly improved cognitive functions, as indicated by the improved performance in the model. Additionally, histopathology showed a reduction in hippocampal neuronal damage. This can be attributed to the potential of Leonurine to reduce Aβ1-40 and Aβ1-42 levels and alleviate oxidative stress. Its antioxidant effect is linked to the activation of the Nrf-2 signaling pathway in APP/PS1 mice, which promotes Nrf-2 nuclear translocation and expression of HO-1 and NQO-1.

Conclusion

These findings suggest that Leonurine could be explored further as it could emerge as a promising drug for AD treatment.