The Downregulation of ITGAX Exacerbates Amyloid-β Plaque Deposition in Alzheimer’s Disease by Increasing Polarization of M1 Microglia

Abstract

Background: Alzheimer’s disease (AD) is the most common sort of neurodegenerative dementia, characterized by its challenging, diverse, and progressive nature. Despite significant progress in neuroscience, the current treatment strategies remain suboptimal. Objective: Identifying a more accurate molecular target for the involvement of microglia in the pathogenic process of AD and exploring potential mechanisms via which it could influence disease. Methods: We utilized single-cell RNA sequencing (scRNA-seq) analysis in conjunction with APP/PS1 mouse models to find out the molecular mechanism of AD. With the goal of investigating the cellular heterogeneity of AD, we downloaded the scRNA-seq data from the Gene Expression Omnibus (GEO) database and identified differentially expressed genes (DEGs). Additionally, we evaluated learning and memory capacity using the behavioral experiment. We also examined the expression of proteins associated with memory using western blotting. Immunofluorescence was employed to investigate alterations in amyloid plaques and microglia. Results: Our findings revealed an upregulation of ITGAX expression in APP/PS1 transgenic mice, which coincided with a downregulation of synaptic plasticity-related proteins, an increase in amyloid-β (Aβ) plaques, and an elevation in the number of M1 microglia. Interestingly, deletion of ITGAX resulted in increased Aβ plaque deposition, a rise in the M1 microglial phenotype, and decreased production of synaptic plasticity-related proteins, all of which contributed to a decline in learning and memory. Conclusions: This research suggested that ITGAX may have a beneficial impact on the APP/PS1 mice model, as its decreased expression could exacerbate the impairment of synaptic plasticity and worsen cognitive dysfunction.