Dysregulated m6A RNA methylation in tuberculosis: association with altered methyltransferase expression and immune responses

Abstract Objective Tuberculosis (TB) remains a global health threat with an incompletely understood pathogenesis. The RNA epigenetic modification N6-methyladenosine (m6A) is a key regulator of immune responses in various diseases, but its role in human TB is largely unexplored. This study aimed to investigate the involvement of m6A modification in TB by profiling its dynamics and the expression of its regulatory enzymes in clinical cohorts. Method In this cross-sectional study, 105 participants were enrolled and classified into four groups based on clinical and laboratory findings: microbiologically-confirmed pulmonary tuberculosis (PTB), interferon-gamma release assay positive (IGRAs-positive), healthy controls (HC), and symptomatic controls (SC). Nutritional, inflammatory, and immunological indicators, including total protein (TP), albumin (ALB), prognostic nutritional index (PNI), Lymphocyte (LY), Neutrophil (NE), platelet-to-lymphocyte ratio (PLR), and neutrophil-to-lymphocyte ratio (NLR), were collected. Circulating m6A levels were systematically evaluated using highly sensitive methods, and the mRNA expression of key m6A regulators (writers: METTL3/14, WTAP; eraser: FTO, ALKBH5; reader: YTHDF2) were quantified via quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR). Results Compared with the HC group, the PTB and IGRAs-positive groups showed significantly decreased LY%, TP, ALB, and PNI, along with increased NE%, PLR, and NLR (P < 0.05). No significant difference in m6A levels was observed between the HC and SC groups. However, m6A levels in the PTB and IGRAs-positive groups were significantly lower than those in the HC group and were positively correlated with clinical indicators reflecting immune response status (P < 0.05). Moreover, m6A methyltransferases exhibited distinct expression patterns across groups with different infection statuses, suggesting a key regulatory role in immune responses. Conclusion Our study unveils a significant reduction in m6A modification and a dysregulated expression of its regulatory enzymes during Mycobacterium tuberculosis infection, which correlates with altered immune-nutritional status. These findings position m6A modification as a novel immunomodulatory mechanism in TB pathogenesis, offering fresh insights into the epitranscriptomic landscape of TB and providing a rationale for future research into its translational relevance.