Comprehensive Analysis of N⁶-Methyladenosine (m⁶A) Methylation in Neuromyelitis Optica Spectrum Disorders

Background: N⁶-Methyladenosine (m⁶A) methylation is the most prevalent internal posttranscriptional modification on mammalian mRNA. But its role in neuromyelitis optica spectrum disorders (NMOSD) is not known. Aims: To explore the mechanism of m⁶A in NMOSD patients. Methods: This study assessed the m⁶A methylation levels in blood from two groups: NMOSD patients and healthy controls. Methylated RNA immunoprecipitation Sequencing (MeRIP-seq) and RNA-seq were performed to assess differences in m⁶A methylation between NMOSD patients and healthy controls. Ultra-high performance liquid chromatography coupled with triple quadruple mass spectrometry (UPLC-QQQ-MS) method was performed to check m⁶A level. Differential m⁶A methylation genes were validated by MeRIP-qPCR. Results: Compared with that in the control group, the total m6A level was decreased in the NMOSD group. Genes with upregulated methylation were primarily enriched in processes associated with RNA splicing, mRNA processing, and innate immune response, while genes with downregulated methylation were enriched in processes associated with the regulation of transcription, DNA-templating, and the positive regulation of I-kappa B kinase/NF-kappa B signalling. Conclusion: These findings demonstrate that differential m⁶A methylation may act on functional genes to regulate immune homeostasis in NMOSD.