Single-cell transcriptomic and m6A methylation analyses reveal platelet-mediated immune regulatory mechanisms in...

Sepsis is a systemic inflammatory response syndrome triggered by infection, characterized by high clinical heterogeneity and complex immunopathological mechanisms. Immune dysregulation plays a central role in its progression. This study aims to investigate the compositional changes of immune cells, characteristics of intercellular communication, and potential regulatory mechanisms of N⁶-methyladenosine (m⁶A) modification in sepsis, with a particular focus on the functional remodeling of platelets.

This study integrated single-cell RNA sequencing data (GSE167363 dataset) from sepsis patients with m⁶A methylation sequencing data of peripheral blood mononuclear cells (PBMCs). Through systematic analysis, we compared the differences in immune cell composition, developmental trajectories, intercellular communication, and m⁶A modifications among healthy controls, survivors, and non-survivors, and further screened for key m⁶A-regulated target genes.

The analysis revealed that platelets gradually accumulated during the progression of sepsis, while B cells, T cells, and regulatory T cells (Tregs) exhibited a trend toward platelet-like phenotypic remodeling. Cell-cell communication analysis showed a marked decline in communication strength among immune cells as the disease worsened, particularly a significant weakening of the APP-CD74 signaling pathway between platelets and B cells, indicating impaired immune network synergy. m⁶A methylation sequencing revealed distinct remodeling of m⁶A peaks and dysregulation of related regulatory factors in non-survivors. Further integrative analysis identified RPA1 as a key m⁶A-regulated target gene, whose expression was closely associated with APP and co-regulated by multiple m⁶A-modifying factors.

This study reveals disruptions in immune cell interactions and an m⁶A-dependent mechanism of platelet functional remodeling during sepsis progression. The identification of the key target gene RPA1 offers new insights into the immunopathological mechanisms of sepsis and lays a theoretical foundation for future precision interventions and therapeutic strategies.