Modification of m6A mediates tissue immune microenvironment in calcific aortic valve disease

BACKGROUND: Several human diseases are associated with aberrant expression of regulators involved in N6-methyladenosine (m6A) RNA modification. However, their role in aortic valve calcification (AVC) is largely unknown. The aim of this study was to determine the general expression pattern and potential function of m6A regulators in AVC by bioinformatics methods. METHODS: We obtained AVC datasets from the Gene Expression Omnibus (GEO). The identification of m6A-related differentially expressed genes (DEGs) and the Consensus Clustering method was performed to type AVC individuals based DEGs. Then, we quantified the effect of typing by principal component analysis (PCA). Next, we performed the weighted gene co-expression network analysis (WGCNA) and identified the main modules as well as functional analysis. Additionally, the key genes were screened by protein-protein interaction network (PPIN) analysis and identifying important genes of important modules. We again typed AVC individuals by the same method using key genes. Finally, we evaluated the link between key genes and immune infiltration. RESULTS: We discovered that METTL14, ZC3H13, FTO, FMR1, HNRNPA2B1, HNRNPC, LRPPRC, YTHDC1, YTHDC2, and YTHDF1 expression levels decreased considerably in AVC tissues. Based on 10 genes, we typed 240 AVC samples as clusters A and B. We assessed the immune cell content in 240 samples using Cell-type Identification by Estimating Relative Subsets of RNA Transcripts (CIBERSORT) and found that B cell memory, CD8 T cells, T follicular helper cells, monocytes, M0 macrophages, resting dendritic cells (DCs), and interleukin-10 (IL-10) were concentrated in the cluster A group. Additionally, based on the important WGCNA modules, we identified 7 key genes. Next, 240 samples were retyped based on 7 key genes; we found that T cells CD8, T cells CD4 memory activated, T cells follicular helper, and macrophages M1 were significantly increased in gene cluster-1. Finally, we performed functional enrichment of gene cluster-typed samples, showing potential functional differences between different types. CONCLUSIONS: Our study provides a review of the m6A regulators’ expression pattern and functional importance in human AVC. The data from this study might serve as a significant resource for future mechanistic and therapeutic investigations into the role of critical m6A regulators in AVC.