Exosomes Derived from ADSCs Attenuate Sepsis-Induced Lung Injury by Delivery of Circ-Fryl and Regulation of the miR-490-3p/SIRT3 Pathway.

Sepsis-induced lung injury is a clinical syndrome characterized by injury of alveolar epithelium cells (AECs). Previous investigations illustrate that exosomes secreted from adipose-derived stem cells (ADSCs) have therapeutic effects in a variety of disease treatments, but roles and mechanisms regarding ADSC-derived exosomes in sepsis-induced lung injury are unclear. In this study, high-throughput sequencing was used to explore the molecular delivery of ADSC exosomes. A sepsis-induced lung injury mouse model and a lipopolysaccharide-induced AEC damage model were used for mechanistic analysis. The results showed that ADSC exosomes have high levels of the circular RNA (circ)-Fryl. Downregulation of circ-Fryl suppressed ADSC protective effects exosomes against sepsis-induced lung injury by decreasing apoptosis and inflammatory factor expression. Bioinformatics and luciferase reporting experiments showed that miR-490-3p and SIRT3 are downstream targets of circ-Fryl. miR-490-3p overexpression or SIRT3 silencing reversed ADSC exosome protective effects. Studying the mechanism showed that overexpression of circ-Fryl promoted autophagy activation by inducing SIRT3/AMPK signaling. Autophagy activation can suppress sepsis-induced lung injury by decreasing apoptosis and inflammatory factor expression. Taken together, our results suggest that exosomes derived from ADSCs attenuate sepsis-induced lung injury by delivery of circ-Fryl and regulation of the miR-490-3p/SIRT3 pathway.