Transcriptome-wide assessment of N6-methyladenosine modification identifies different gene expression and infection-associated pathways in Treponema pallidum-infected macrophage

Treponema pallidum (Tp) is a widespread and destructive pathogen that leads to syphilis. As the acknowledged executor of host immunity, macrophage plays vital roles in combating the invasion and migration of Tp. However, the mechanisms of these processes are largely unknown, especially the critical driver genes and associated modifications.We aimed to systematically dissect the global N6-methyladenosine (m6A) RNA modification patterns in Tp-infected macrophages.The RNA of Tp-infected/non-infected macrophage was extracted, followed by mRNA sequencing and methylated RNA immunoprecipitation (MeRIP) sequencing. Bioinformatics analysis was executed by m6A peaks and motifs identification, Gene ontology and signaling pathways analysis of differentially expressed genes, and comprehensive comparison. The m6A levels were measured by RNA Methylation Assay, and m6A modified genes were determined by qPCR.Totally, 2623 unique and 3509 common m6A peaks were proved along with related transcripts in Tp-infected macrophages. The common m6A-related genes were enriched in the signals of oxidative stress, cell differentiation, and angiogenesis, while unique genes in those of metabolism, inflammation, and infection. And differentially expressed transcripts revealed various biological processes and pathways associated with catabolic and infection. They also experienced comprehensive analysis due to hyper-/hypo-methylation. And the m6A level of macrophage was elevated, along with qPCR validation of specific genes.With a particular m6A transcriptome-wide map, our study provides unprecedented insights into the RNA modification of macrophage stimulated by Tp in vitro, which partially differs from other infections and may provide clues to explore the immune process for syphilis.