Exosomal Drug Delivery Systems: A Novel Therapy Targeting PD-1 in Septic-ALI

The cytokine storm triggered by sepsis can lead to the development of acute lung injury (ALI). Human umbilical cord Mesenchymal stem cells derived exosomes (HucMSCs-EXOs) have been demonstrated to possess immunosuppressive and anti-inflammatory properties. Programmed cell death receptor 1 (PD-1) plays a crucial role in maintaining the inflammatory immune homeostasis. The aim of this study is to investigate the synergistic therapeutic effect of EXOs loaded with anti-PD-1 peptide on septic-ALI.

This study prepares a novel EXOs-based drug, named MEP, by engineering modification of HucMSCs-EXOs, which are non-immunogenic extracellular vesicles, loaded with anti-PD-1 peptide. The therapeutic effect and potential mechanism of MEP on septic-ALI are elucidated through in vivo and in vitro experiments, providing experimental evidence for the treatment of septic acute lung injury with MEP.

We found that, compared to individual components (anti-PD-1 peptide or EXOs), MEP treatment can more effectively improve the lung injury index of septic-ALI mice, significantly reduce the expression levels of inflammatory markers CRP and PCT, as well as pro-inflammatory cytokines TNF-α and IL-1β in serum, decrease lung cell apoptosis, and significantly increase the expression of anti-inflammatory cytokine IL-10 and CD68⁺ macrophages. In vitro, MEP co-culture promotes the proliferation of CD206⁺ macrophages, increases the M2/M1 macrophage ratio, and attenuates the inflammatory response. GEO data analysis and qRT-PCR validation show that MEP reduces the expression of inflammasome-related genes and M1 macrophage marker iNOS.

In both in vitro and in vivo settings, MEP demonstrates superior therapeutic efficacy compared to individual components in the context of septic-ALI.