循环RNA（circRNA）作为竞争性内源性RNA（ceRNA）或微小RNA（miRNA）海绵，在癌症中起着重要作用。然而，circRNA在肝纤维化中的功能和机制仍未知，是本研究的重点。利用硫代乙酰胺（TAA）或四氯化碳（CCl4）诱导小鼠纤维模型。TAA和CCl4诱导的小鼠纤维病变肝脏伴有增加的血管生成。在小鼠肝脏中进行circRNA微阵列和角蛋白2（AGO2）-RNA免疫共沉淀（RIP）测序以筛选功能性circRNA。与对照肝相比，使用circRNA微阵列在TAA诱导的小鼠纤维病变肝脏中获得86个差异表达的circRNA。此外，使用AGO2-RIP测序探索了551个小鼠纤维病变肝脏circRNA。然后选择并验证circRNA-007371的回转接点、对RNase R的抗性和环形形成。在体外，将circRNA-007371过表达质粒或空质粒转染小鼠血管内皮瘤（EOMA）细胞。circRNA-007371过表达促进了EOMA细胞管形成、迁移和细胞增殖。然后进行RNA测序和miRNA测序，以探索circRNA-007371促血管生成效应的机制。circRNA-007371通过miRNA海绵或ceRNA机制促进肝纤维化。circRNA-007371的母源基因Stag1可能在促进血管化进展中发挥重要作用。总之，circRNA-007371通过miRNA海绵机制增强肝纤维化中的血管生成。circRNA-007371抑制的抗血管生成效应可能为治疗肝硬化患者提供了一种新策略。©2023作者。《Cell Proliferation》由北京干细胞与再生医学研究所和约翰威利和儿子有限公司出版。

Circular RNAs (circRNAs) are crucially involved in cancers as competing endogenous RNA (ceRNA) or microRNA (miRNA) sponges. However, the function and mechanism of circRNAs in liver fibrosis remain unknown and are the focus of this study. Murine fibrotic models were induced by thioacetamide (TAA) or carbon tetrachloride (CCl4 ). Increased angiogenesis is accompanied by liver fibrosis in TAA- and CCl4 -induced murine fibrotic livers. circRNA microarray and argonaute 2 (AGO2)-RNA immunoprecipitation (RIP) sequencing (AGO2-RIP sequencing) were performed in murine livers to screen for functional circRNAs. Compared to control livers, 86 differentially expressed circRNAs were obtained in TAA-induced murine fibrotic livers using circRNA microarray. In addition, 551 circRNAs were explored by AGO2-RIP sequencing of murine fibrotic livers. The circRNA-007371 was then selected and verified for back-spliced junction, resistance to RNase R, and loop formation. In vitro, murine hemangioendothelioma endothelial (EOMA) cells were transfected with circRNA-007371 overexpressing plasmid or empty plasmid. circRNA-007371 overexpression promoted tube formation, migration, and cell proliferation of EOMA cells. RNA sequencing and miRNA sequencing were then performed to explore the mechanism of the proangiogenic effects of circRNA-007371. circRNA-007371 promotes liver fibrosis via miRNA sponges or ceRNA mechanisms. Stag1, the parent gene of circRNA-007371, may play a significant role in proangiogenic progression. In conclusion, circRNA-007371 enhances angiogenesis via a miRNA sponge mechanism in liver fibrosis. The antiangiogenic effect of circRNA-007371 inhibition may provide a new strategy for treating patients with liver cirrhosis.© 2023 The Authors. Cell Proliferation published by Beijing Institute for Stem Cell and Regenerative Medicine and John Wiley & Sons Ltd.