Alveolar macrophage exosomal tRNA-derived fragments tRF-22-8BWS7K092 promote ferroptosis to involve in acute lung injury

Macrophage exosomes play a demonstrative role in acute lung injury (ALI) by mediating cellu-lar communication. Transfer RNA-derived fragments (tRFs) possess potential functions in mul-tiple diseases through ferroptosis. The present study aims to reveal the role of macrophage exo-somal tRFs in ALI and to identify the relationship to ferroptosis. ALI mice model and cell model were established by lipopolysaccharide (LPS) induction. RNA sequencing was performed to identify the tRFs profile in exosomes of ALI mice. After interfering with the expression of can-didate tRFs in macrophages or lung epithelial cells (MLE-12), the effect of oxidative stress and expression of ferroptosis-related proteins were detected. Here, LPS induced lung injury was characterized by alveolar walls and interstitial spaces thickening, hemorrhage, and inflamma-tion. RNA sequencing identified 4 up- and 10 down-regulated differentially expressed tRFs (DEtRFs) in the exosomes of ALI mice. The GO function of exosomal DEtRFs enriched in gene regulation related terms such as transcription regulation and protein binding. Hippo signaling pathway was the most significantly enriched KEGG pathways for DEtRFs. LPS-induced macro-phage exosome (LPS-exo) inhibited the viability and the expression of GPX4 and FTH1, and en-hanced the oxidative stress in MLE-12 cells. Ferroptosis inhibitor reversed the inhibition of LPS-exo on cell viability. Also, tRF-22-8BWS7K092 inhibitor rescued the above effect of LPS-exo on MLE-12 cells. Besides, tRF-22-8BWS7K092 activates Hippo signaling pathway by binding Wnt5B, resulting in ferroptosis in MLE-12 cells. In conclusion, we obtained and characterized the exosomal tRFs expression profile in ALI mice. LPS-induced macrophage exosomal tRF-22-8BWS7K092 involved in the process of ALI by promoting ferroptosis. Our study provides a new molecular target for the treatment of ALI.