Extracellular Vesicle-Mediated Delivery of HIF1a Reprograms Macrophages for resolutive response in Sepsis

Abstract In sepsis, the liver functions as a central filter organ, where hepatic macrophages form a primary antimicrobial defense layer by eliminating bacteria and regulating immune responses. Therefore, precise regulation of the immune response in hepatic macrophages is crucial for triggering effective defense mechanisms. We aim to modulate the defense immune response by delivering transcription factor HIF1α, a key regulator of monocyte/macrophage reprogramming in sepsis. Transcription factors are promising candidates because they dynamically modulate gene expression across diverse conditions, though delivering them remains challenging. In this study, we suggest a novel method for loading HIF1α into extracellular vesicles (EVs) to enhance immune defense and resolve sepsis. By delivering HIF1α to macrophages during sepsis, we promoted the differentiation of Nr1h3-dependent pro-efferocytic MoMFs and C/ebpβ-dependent pro-survival MoMFs. Pro-efferocytic MoMFs eliminate damaged hepatocytes and immune cells and pro-survival MoMFs withstand inflammatory conditions and trigger innate memory responses. Particularly, the zonation of these macrophages in the periportal region ensures effective pathogen clearance and minimizes tissue damage. These findings suggest that EV-mediated HIF1α delivery could be a promising therapeutic option for managing sepsis.