Prolonged parenchymal cell death leads to activation of fibrogenic cells, extracellular matrix accumulation, and eventually liver fibrosis. Increasing evidence shows that exosomes (Exos) secreted by adipose-derived mesenchymal stem cells (ADSCs) can be used to deliver circular RNAs (circRNAs) to treat liver fibrosis. To explore the uses of circRNA, circRNA expression profiles of hepatic tissue from normal and CCl4-induced mice were analyzed using high-throughput circRNA microarrays. The result showed that mmu_circ_0000623 expression was downregulated in CCl4-induced mice. Bioinformatics analysis and luciferin reporter experiments showed that mmu_circ_0000623 interacted with and regulated miR-125/ATG4D. In vitro and in vivo experiments showed that Exos from ADSCs, especially from mmu_circ_0000623-modified ADSCs, significantly suppressed CCl4-induced liver fibrosis by promoting autophagy activation. Autophagy inhibitor treatment significantly reversed the treatment effects of Exos. Proteins involved in autophagy and autophagy plaques positive for ATG4D expression were regulated by mmu_circ_0000623/miR-125. Our study found that Exos derived from mmu_circ_0000623-modified ADSCs prevented liver fibrosis via activating autophagy.
Keywords: Exosomes; adipose-derived mesenchymal stem cells; autophagy; liver fibrosis; mmu_circ_0000623.