Potential targets of glucagon-like peptide 1 receptor agonist ticagrelor in the treatment of Alzheimer’s disease

Abstract

BACKGROUND: Glucagon-like peptide 1 receptor agonists, as novel drug candidates for the treatment of neurodegenerative diseases, have achieved breakthrough progress in clinical research on Alzheimer’s disease, with drugs such as Semaglutide advancing to phase III clinical trials. However, there remains a significant knowledge gap regarding the molecular mechanism of neuroprotective effects of these drugs. OBJECTIVE: To innovatively integrate multi-omics analysis techniques and network pharmacology methods, to systematically analyze the intersection network between the gene lineage related to Alzheimer’s disease pathology and the potential targets of ticagrelor, to identify key regulatory genes, and to verify their molecular mechanisms through in vitro and in vivo experiments. METHODS: A multi-dimensional research strategy was adopted: (1) Constructing the differential expression gene profile of Alzheimer’s disease using the DisGeNET database that covers various disease-related genomics. (2) Obtaining the structure of Tirzepatide from PubChem database with bioactive molecules and screening potential targets. (3) Conducting Gene Ontology (GO) functional annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis using DAVID database. (4) Constructing protein-protein interaction network using STRING database and Cytoscape 3.9.1, and screening key genes via topological network analysis. (5) Cell-level verification: HT22 cells were divided into control group, model group (treated with β-amyloid 1-42 oligomers for 36 h to establish an in vitro AD model), and treatment group (pretreated with β-amyloid 1-42 oligomers for 24 h, then co-treated with ticagrelor for 12 h). Western blot was used to analyze the protein expression of angiotensin II type 2 receptor (AGTR2), and ELISA was used to detect the expression levels of synaptic markers such as synaptophysin 1 and postsynaptic density protein 95. (6) Animal experiments: Three groups were used: control group (WT C57BL/6 mice, intraperitoneal injection of saline), model group (3xTg mice, intraperitoneal injection of saline), and treatment group (3xTg mice, intraperitoneal injection of 20 nmol/L ticagrelor), all administered every other day for a total of 15 doses. Morris water maze was used to analyze cognitive behavioral improvements in AD model mice; Western blot was used to quantitatively analyze the expression of β-amyloid (6E10) and phosphorylated Tau protein (P-tau-181). RESULTS AND CONCLUSION: (1) A total of 3,397 AD-related genes were screened from DisGeNET database; 10 key genes with the highest connectivity were identified based on protein association: AGTR2, NTSR1, NTSR2, GHSR, C5AR1, C3AR1, OPRM1, SSTR2, OPRD1, STAT3. GO enrichment and KEGG pathway analysis suggested that ticagrelor may improve AD by enhancing neuroreceptor-ligand function. (2) Cell experiments suggested that ticagrelor may exert therapeutic effects by improving synaptic function in AD, and AGTR2 may be a potential target of ticagrelor in treating AD. (3) Animal experiments indicated that ticagrelor improved cognitive ability in 3xTg mice, and ameliorated abnormal β-amyloid deposition and Tau protein phosphorylation in the brain of 3xTg mice. (4) Conclusion: The study reveals that AGTR2 is a key molecular target of ticagrelor in the pathological process of AD, and ticagrelor may treat AD by regulating AGTR2-mediated synaptic function improvement.

1. Introduction

Alzheimer's disease (AD), as a major type of central nervous system degenerative disease, is characterized clinically by progressive cognitive decline and behavioral abnormalities [1]. The disease process exhibits distinct stages, evolving from mild cognitive impairment to complete dementia. Currently, the pathogenesis of AD is not fully understood, but it is widely recognized that the pathological process involves complex interactions of multiple factors, including the β-amyloid toxicity hypothesis, Tau protein dysfunction theory, neurotransmitter system imbalance, oxidative stress injury, neuroinflammation, and synaptic dysfunction [1-5]. Various pathological changes can lead to synaptic and neuronal loss in regions such as the hippocampus. Alterations in hippocampal neurogenesis represent an early key event in AD [6], and synaptic loss is closely related to cognitive decline in human and animal models of AD [7]. The non-regenerative nature of neurons is a significant challenge in treating neurological diseases.

Glucagon-like peptide 1 receptor agonists (GLP-1RAs) have emerged as novel drug candidates for neurodegenerative diseases, with breakthrough progress in clinical trials for AD. For instance, semaglutide has advanced to phase III clinical trials. However, the molecular mechanisms underlying the neuroprotective effects of these drugs remain largely unknown. This study aims to integrate multi-omics analysis and network pharmacology to systematically analyze the intersection network between AD-related genes and potential targets of ticagrelor, identify key regulatory genes, and validate their molecular mechanisms through in vitro and in vivo experiments.