NEAT1/miR-181a-5p/HMGB1 Axis Regulates Macrophage Polarization and Inflammation in Sepsis Models

Sepsis is characterized by a dysregulated host immune response and remains a leading cause of mortality worldwide. Long non-coding RNA NEAT1 has been implicated in inflammatory diseases, but its specific role in macrophage polarization during sepsis has not been fully defined. Here, we systematically examine the NEAT1/miR-181a-5p/HMGB1 axis across clinical samples, cultured macrophages, and a CLP mouse model. Quantitative PCR, western blotting, dual-luciferase reporter assays, and RNA pull-down experiments are used to confirm the competitive endogenous RNA (ceRNA) interaction among NEAT1, miR-181a-5p, and HMGB1. Functional assays, including immunofluorescence, transwell migration, and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining, are applied to assess macrophage polarization, migration, and apoptosis. In vivo, the CLP model combined with ELISA and histopathology validates the impact of NEAT1 knockdown on cytokine profiles and organ injury. NEAT1 and HMGB1 are upregulated, whereas miR-181a-5p is downregulated, in patients with sepsis and in lipopolysaccharide-stimulated macrophages. Silencing NEAT1 promotes M2 macrophage polarization, reduces pro-inflammatory cytokines, impairs macrophage migration, and alleviates tissue damage in septic mice via the miR-181a-5p/HMGB1 axis. To our knowledge, this is the first integrated protocol to characterize the lncRNA-microRNA-HMGB1 regulatory circuit in sepsis using harmonized clinical, in vitro, and in vivo approaches. It provides a methodological framework for targeting NEAT1-related ceRNA networks as potential therapeutic strategies.