Single-cell transcriptomic analysis reveals therapeutic mechanisms of adipose-derived stem cell exosomes in sepsis-induced lung injury

Abstract

Background: Sepsis-induced acute lung injury (ALI) remains a leading cause of mortality in critically ill patients, with limited effective treatments beyond supportive care. This study investigates the therapeutic efficacy and underlying mechanisms of adipose-derived stem cell (ADSC) exosomes on sepsis-induced lung injury and characterize underlying cellular and molecular mechanisms.

Methods: We employed a cecal ligation and puncture (CLP) mouse model of sepsis and using male C57BL/6 J mice (Mus musculus, 8-10 weeks old) and administered ADSC-derived exosomes intravenously. Animals were randomly assigned to Sham, CLP, or CLP + ADSC-exosome groups. Survival rates (n =12 for each group) and lung histopathology (n =5 for each group) were assessed. Single-cell RNA sequencing was performed on lung tissues to analyze cell type-specific transcriptomic changes and intercellular communication networks (n =2 for each group).

Results: ADSC exosome treatment significantly improved survival rates and reduced lung pathology in CLP mice. Treatment altered lung cellular composition, increasing neutrophils, NKT cells, and monocytes while decreasing B and T cells. Gene expression analysis revealed downregulation of pro-inflammatory markers (TNF, IL-10, CCL3, CCL4) and upregulation of tissue repair pathways. In neutrophils, exosomes reduced expression of respiratory burst genes while enhancing tissue repair mechanisms. In monocytes, treatment suppressed inflammatory cytokine production while promoting anti-inflammatory phenotypes. Exosome treatment is associated with transcriptomic changes suggestive of restored intercellular communication networks disrupted by sepsis, with increased signaling via CSF3, ANGPT, SPP1, and CCL pathways.

Conclusion: ADSC-derived exosomes effectively treat sepsis-induced lung injury by rebalancing the cellular environment and restoring homeostasis through modulation of immune cell function and intercellular communication, offering potential as a cell-free novel therapeutic approach for sepsis-related pulmonary complications.

Keywords: acute lung injury; adipose-derived stem cells; exosomes; sepsis; single-cell RNA sequencing (scRNA-seq).