Identification of M2 Macrophage-Related Key Genes in Advanced Atherosclerotic Plaques by Network-Based Analysis

Abstract: Atherosclerotic plaque accounts for major adverse cardiovascular events because of its vulnerability. The classically activated macrophage (M1) and alternatively activated macrophage (M2) are implicated in the progression and regression of plaque, respectively. However, the therapeutic targets related to M2 macrophages still remain largely elusive. In this study, cell-type identification by estimating relative subsets of RNA transcripts and weighted gene coexpression network analysis algorithms were used to establish a weighted gene coexpression network for identifying M2 macrophage-related hub genes using GSE43292 data set. The results showed that genes were classified into 7 modules, with the blue module (Cor = 0.67, P = 3e−05) being the one that was most related to M2 macrophage infiltration in advanced plaques, and then 99 hub genes were identified from blue module. Meanwhile, 1289 differentially expressed genes were produced in GSE43292 data set. Subsequently, the intersection genes of hub genes and differentially expressed genes, including AKTIP , ASPN , FAM26E , RAB23 , PLS3 , and PLSCR4 , were obtained by Venn diagrams and named as key genes. Further validation using data sets GSE100927 and GSE41571 showed that 6 key genes all downregulated in advanced and vulnerable plaques compared with early and stable plaque samples (|Log2 (fold change)| > 0.5, P < 0.05 or 0.001), respectively. Receiver operator characteristic curve analysis indicated that the 6 key genes might have potential diagnostic value. The validation of key genes in the model in vitro and in vivo also demonstrated decreased mRNA expressions of AKTIP , ASPN , FAM26E , RAB23 , PLS3 , and PLSCR4 ( P < 0.05 or 0.001). Collectively, we identified AKTIP, ASPN, FAM26E, RAB23, PLS3, and PLSCR4 as M2 macrophage-related key genes during atherosclerotic progression, proposing potential intervention targets for advanced atherosclerotic plaques.