Endothelial-mesenchymal transition (EndoMT) plays a critical role in the dysfunction of the blood–brain barrier (BBB). Circular RNAs (circRNAs) function as crucial regulatory factors in EndoMT. Nevertheless, the underlying mechanisms of circRNA HECW2 (circ_HECW2, hsa_circ_0057583) in lipopolysaccharide (LPS)-induced EndoMT remain largely unclear. The levels of circ_HECW2, miR-30e-5p and neuronal growth regulator 1 (NEGR1) were detected by quantitative real-time polymerase chain reaction (qRT-PCR) or western blot. Ribonuclease (RNase) R and Actinomycin D assays were performed to validate the stability of circ_HECW2. Cell colony formation, proliferation and apoptosis were tested by a standard colony formation assay, the 3-(4,5-dimethylthiazol-2yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)–2H-tetrazolium (MTS) assay and flow cytometry, respectively. Targeted relationships among circ_HECW2, miR-30e-5p and NEGR1 were verified by a dual-luciferase reporter assay. Our data indicated that LPS increased circ_HECW2 expression and reduced miR-30e-5p expression in human brain microvascular endothelial cells (HBMECs). Circ_HECW2 silencing promoted cell proliferation and suppressed cell apoptosis and EndoMT in LPS-treated HBMECs. Mechanistically, circ_HECW2 directly interacted with miR-30e-5p by binding to miR-30e-5p. MiR-30e-5p was a functional mediator of circ_HECW2 in regulating LPS-induced cell EndoMT. Furthermore, Circ_HECW2 regulated NEGR1 expression through functioning as a miR-30e-5p sponge. Moreover, miR-30e-5p overexpression repressed the EndoMT of LPS-treated HBMECs by targeting NEGR1. Collectively, our current study demonstrated that circ_HECW2 silencing suppressed LPS-triggered HBMEC EndoMT at least in part through the regulation of the miR-30e-5p/NEGR1 axis, illuminating a promising strategy for EndoMT inhibition.

内皮间质转化 (EndoMT) 在血脑屏障 (BBB) 功能障碍中起关键作用。环状 RNA (circRNAs) 在 EndoMT 中作为重要的调控因子发挥作用。然而，circRNA HECW2（circ_HECW2，hsa_circ_0057583）在脂多糖（LPS）诱导的EndoMT中的潜在机制仍不清楚。通过定量实时聚合酶链反应 (qRT-PCR) 或蛋白质印迹检测 circ_HECW2、miR-30e-5p 和神经元生长调节剂 1 (NEGR1) 的水平。进行核糖核酸酶 (RNase) R 和放线菌素 D 测定以验证 circ_HECW2 的稳定性。细胞集落形成、增殖和凋亡通过标准集落形成测定法进行测试，即 3-(4,5-二甲基噻唑-2基)-5-(3-羧基甲氧基苯基)-2-(4-磺基苯基)-2H-四唑鎓 (MTS) ) 测定和流式细胞术，分别。通过双荧光素酶报告基因检测验证了 circ_HECW2、miR-30e-5p 和 NEGR1 之间的靶向关系。我们的数据表明，LPS 增加了人脑微血管内皮细胞 (HBMEC) 中 circ_HECW2 的表达并降低了 miR-30e-5p 的表达。在 LPS 处理的 HBMECs 中，Circ_HECW2 沉默促进细胞增殖并抑制细胞凋亡和 EndoMT。从机制上讲，circ_HECW2 通过与 miR-30e-5p 结合直接与 miR-30e-5p 相互作用。MiR-30e-5p 是 circ_HECW2 调节 LPS 诱导的细胞 EndoMT 的功能介质。此外，Circ_HECW2 通过充当 miR-30e-5p 海绵来调节 NEGR1 表达。此外，miR-30e-5p 过表达通过靶向 NEGR1 抑制 LPS 处理的 HBMECs 的 EndoMT。总的来说，