Adipose stem cell vesicles reduce bleomycin-induced dermal fibrosis and oxidative stress in scleroderma mice via...

Systemic sclerosis (SSc) is an autoimmune condition affecting several organs. It is identified by thickening of the dermis, connective tissue affected by collagen accumulation, and vascular injuries that induce hypoxia. The present study aimed to determine whether extracellular vesicles (EVs) from adipose-derived stem cells (ADSCs) attenuated bleomycin-induced skin fibrosis and oxidative stress in scleroderma. ADSCs and their EVs were separated and a bleomycin-induced SSc mouse model was constructed. High-throughput sequencing was employed to study abnormal expression of circular RNAs in SSc skin tissues with or without ADSC-EV treatment. The regulatory mechanism and targets were studied using bioinformatics analysis, luciferase reporting analysis, angiogenic differentiation experiments, and RT-qPCR detection analysis. EVs from ADSCs were successfully isolated. The exosome treatment prevented dermal thickening and fibrosis in bleomycin-induced scleroderma. In addition, circ-Zfyve9 was demonstrated to have an important function in ADSC-EV-mediated skin tissue protection. GPX4 and miR-135 were shown to be downstream targets of circ-Zfyve9. Overexpressing miR-135 or downregulating GPX4 reversed the promotion effects of circ-Zfyve9 on angiopoiesis by increasing lipidosome ROS in EPCs under hypoxic conditions. Overexpressing miR-135 or downregulating GPX4 reversed the inhibition effect of circ-Zfyve9 on fibrosis in myofibroblasts under hypoxic conditions. Overexpressing circ-Zfyve9 increased the therapeutic effect of ADSC-EVs. EVs from ADSCs attenuated bleomycin-induced skin fibrosis and oxidative stress in scleroderma via circ-Zfyve9 delivery.