SRC-1 Knockout Exerts No Effect on Amyloid β Deposition in APP/PS1 Mice

A review and analysis of key biomarkers in Alzheimer's disease

Alzheimer's disease (AD) is a progressive neurodegenerative disorder that affects over 50 million elderly individuals worldwide. Although the pathogenesis of AD is not fully understood, based on current research, researchers are able to identify potential biomarker genes and proteins that may serve as effective targets against AD. This article aims to present a comprehensive overview of recent advances in AD biomarker identification, with highlights on the use of various algorithms, the exploration of relevant biological processes, and the investigation of shared biomarkers with co-occurring diseases. Additionally, this article includes a statistical analysis of key genes reported in the research literature, and identifies the intersection with AD-related gene sets from databases such as AlzGen, GeneCard, and DisGeNet. For these gene sets, besides enrichment analysis, protein-protein interaction (PPI) networks utilized to identify central genes among the overlapping genes. Enrichment analysis, protein interaction network analysis, and tissue-specific connectedness analysis based on GTEx database performed on multiple groups of overlapping genes. Our work has laid the foundation for a better understanding of the molecular mechanisms of AD and more accurate identification of key AD markers.

Gut-derived β-amyloid: Likely a centerpiece of the gut-brain axis contributing to Alzheimer's pathogenesis

Peripheral β-amyloid (Aβ), including those contained in the gut, may contribute to the formation of Aβ plaques in the brain, and gut microbiota appears to exert an impact on Alzheimer's disease (AD) via the gut-brain axis, although detailed mechanisms are not clearly defined. The current study focused on uncovering the potential interactions among gut-derived Aβ in aging, gut microbiota, and AD pathogenesis. To achieve this goal, the expression levels of Aβ and several key proteins involved in Aβ metabolism were initially assessed in mouse gut, with key results confirmed in human tissue. The results demonstrated that a high level of Aβ was detected throughout the gut in both mice and human, and gut Aβ42 increased with age in wild type and mutant amyloid precursor protein/presenilin 1 (APP/PS1) mice. Next, the gut microbiome of mice was characterized by 16S rRNA sequencing, and we found the gut microbiome altered significantly in aged APP/PS1 mice and fecal microbiota transplantation (FMT) of aged APP/PS1 mice increased gut BACE1 and Aβ42 levels. Intra-intestinal injection of isotope or fluorescence labeled Aβ combined with vagotomy was also performed to investigate the transmission of Aβ from gut to brain. The data showed that, in aged mice, the gut Aβ42 was transported to the brain mainly via blood rather than the vagal nerve. Furthermore, FMT of APP/PS1 mice induced neuroinflammation, a phenotype that mimics early AD pathology. Taken together, this study suggests that the gut is likely a critical source of Aβ in the brain, and gut microbiota can further upregulate gut Aβ production, thereby potentially contributing to AD pathogenesis.

Study on the active components and mechanism of Suanzaoren decoction in improving cognitive impairment caused by sleep deprivation

ETHNOPHARMACOLOGICAL RELEVANCE

Suanzaoren Decoction (SZRD) is a traditional and classic prescription for the treatment of insomnia, with a history of more than 1,000 years. It replenishes blood components, calms the nerves, reduces fever and irritability. It is commonly used in the clinical treatment of chronic fatigue syndrome, cardiac neurosis, and menopausal syndromes. Modern pharmacological studies have shown that it improves cognitive impairment; however, its mechanism of action remains unclear.

AIM OF THE STUDY

This study preliminarily investigated the potential bioactive components and mechanism of SZRD in improving cognitive impairment by exploring network pharmacology, molecular docking, and conducting in vivo experiments.

MATERIALS AND METHODS

The components of various Chinese herbs in SZRD and their disease-related targets were identified through network pharmacology and literature. Gene ontology (GO) function enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses of intersection targets were performed using the relevant database. Next, the "Components-Targets-Pathways" (C-T-P) and "Protein-Protein interaction" networks were constructed using the enrichment analysis results to further identify potential pathways, bioactive components, and hub genes. At the same time, molecular docking was used to further distinguish the key bioactive components and genes of SZRD responsible for improving cognitive impairment. Finally, the potential mechanism of action was further analysed and verified using in vivo experiments.

RESULTS

A total of 117 potential active components and 138 intersection targets were identified by network pharmacology screening. The key bioactive components, including calycosin, 5-Prenylbutein, licochalcone G, glypallichalcone, and ZINC189892, were identified by analysing the networks and molecular docking results. Hub genes included ACHE, CYP19A1, EGFR, ESR1, and ESR2. The oestrogen signalling pathway was the most important in the enrichment analysis. In vivo experiments further proved that SZRD could improve cognitive impairment by affecting the oestrogen signalling pathway and the expression of ACHE and CYP19A1.

CONCLUSIONS

Network pharmacology and in vivo experiments demonstrate that SZRD improves cognitive impairment caused by sleep disturbance through estrogen receptor pathway, which provides a basis for its clinical application.