Analysis of immune-related key genes in Alzheimer’s disease

This research revealed that 15 modules were obtained through weighted gene co-expression network analysis (WGCNA), among which the magenta and blue modules were significantly associated with Alzheimer's Disease (AD). There were 121 genes in the magenta module, and 1022 genes in the blue module. Through the differently expressed genes (DEGs) analysis, significant differences were shown in 134 genes (88 were up-regulated and 46 were down-regulated). 34 immune-key genes were obtained after 3 types of genes were crossed. Functional enrichment analysis showed that these genes were mainly enriched in cytokine receptor activity, immune receptor activity, and integrin family cell surface interactions. Through protein-protein interaction (PPI) network analysis, 10 hub genes were obtained: SERPINE1, ZBTB16, CD44, BCL6, HMOX1, SLC11A1, CEACAM8, ITGA5, SOCS3, and IL4R. Through immune-infiltration analysis, significant differences were demonstrated in 4 immune cells: CD8+ T cells, resting NK cells, M2 macrophages and activated dendritic cells, and a significant positive correlation was shown between CD8+ T cells and macrophages M2, or between resting NK cells and activated dendritic cells. CEACAM8 was positively correlated with CD8+ T cells and macrophages M2, and negatively correlated with activated dendritic cells and resting NK cells while the other 9 genes showed the opposite. Receiver operating characteristic (ROC) curve analysis demonstrated that both the differential immune cells and 10 hub genes had good diagnostic values. In GSE122063, the hub genes were verified and BCL6, CD44, HMOX1, IL4R, ITGA5 and SOCS3 were up-regulated. Meanwhile, the expression of hub genes was up-regulated in the brain tissues of AD rats. This study is of great significance for the diagnosis and therapy of AD.