Sepsis-Induced Exosomal Transfer of MAFB mRNA Reprograms Hepatocytes via a miR-155-Jarid2-H3F3A Epigenetic Cascade

Exosomes carry bioactive macromolecules driving sepsis pathogenesis, but the mechanisms underlying macrophage-to-hepatocyte communication during systemic inflammation remain poorly understood. We investigated how sepsis-induced macrophage exosomes are involved in remote intercellular crosstalk with hepatic cells via transcription factor-encoding mRNA cargo. Human monocytic THP-1 macrophages were stimulated with lipopolysaccharide (LPS), followed by exosome isolation, recipient cell uptake verification, and high-throughput RNA sequencing cargo analysis. To functionally reconstruct downstream signaling in recipient cells, exosome-enriched MAFB mRNA was transiently overexpressed in a HepG2 cell model, with subsequent expression changes mapped at both the transcript and protein levels using quantitative PCR and Western blot analyses. This ectopic MAFB expression directly upregulates the expression of microRNA-155 (miR-155). Crucially, elevated miR-155 acts as a post-transcriptional repressor that directly targets and downregulates JARID2 and H3F3A mRNAs and their corresponding protein products within the liver cells, orchestrating a "repressor-of-repressors" disinhibition cascade that drives net chromatin remodeling and activation of downstream hepatic target genes. This study demonstrates that sepsis alters exosomal transcription factor mRNA cargo and delineates a mechanistic downstream pathway-MAFB → ↑miR155 → ↓Jarid2 & ↓H3F3A → Chromatin Remodeling → Downstream Hepatic Gene Activation pathway-that provides novel, specific molecular checkpoints for therapeutic intervention in sepsis-induced liver injury.