Department of Gastroenterology, The Affiliated Changsha Hospital of Xiangya School of Medicine, Central South University, Changsha, China.
J Gastroenterol Hepatol. 2024 Jul;39(7):1299-1309. doi: 10.1111/jgh.16550. Epub 2024 Apr 22.
Circular RNA (circRNA) has been found to mediate ulcerative colitis (UC) progression by regulating intestinal mucosal barrier function. However, the role of circSOD2 in UC process and its underlying molecular mechanism still need to be further elucidated.
Lipopolysaccharide (LPS)-induced Caco2 cells were used to mimic UC cell models. CircSOD2, miR-378g, and Snail1 levels were determined by quantitative real-time PCR. Cell viability was detected using MTT assay, and inflammatory cytokine levels were measured using ELISA. The intestinal mucosal barrier function was evaluated by testing transepithelial electrical resistance and fluorescein isothiocyanate (FITC)-dextran permeability. Snail1 and tight junction-related markers (Zo-1 and Claudin2) protein levels were examined using western blot. The interaction between miR-378g and circSOD2 or Snail1 was confirmed by dual-luciferase reporter assay. Dextran sulfate sodium (DSS) was used to induce UC rat models in vivo.
CircSOD2 was overexpressed in UC patients, and its knockdown significantly increased cell viability, transepithelial electrical resistance, and tight junction-related protein expression, while reduced inflammation cytokine levels and the permeability of FITC-dextran in LPS-induced Caco2 cells. In terms of mechanism, circSOD2 sponged miR-378g to positively regulate Snail1 expression. MiR-378g inhibitor reversed the effect of circSOD2 knockdown on intestinal mucosal barrier injury and Snail1 expression in LPS-induced Caco2 cells. In DSS-induced UC rat models, circSOD2 knockdown also could repair the intestinal mucosal barrier injury through regulating miR-378g/Snail1 axis.
CircSOD2 could destroy intestinal mucosal barrier function in LPS-induced Caco2 cells and DSS-induced UC rats by miR-378g/Snail1 axis.
环状 RNA（circRNA）已被发现通过调节肠道黏膜屏障功能来介导溃疡性结肠炎（UC）的进展。然而，circSOD2 在 UC 进程中的作用及其潜在的分子机制仍需要进一步阐明。
采用脂多糖（LPS）诱导 Caco2 细胞模拟 UC 细胞模型。采用实时定量 PCR 检测 circSOD2、miR-378g 和 Snail1 的水平。采用 MTT 法检测细胞活力，采用 ELISA 法检测炎症细胞因子水平。通过检测跨上皮电阻和荧光素异硫氰酸酯（FITC）-葡聚糖通透性来评估肠道黏膜屏障功能。采用 Western blot 法检测 Snail1 和紧密连接相关标志物（Zo-1 和 Claudin2）蛋白水平。通过双荧光素酶报告基因实验证实 miR-378g 与 circSOD2 或 Snail1 的相互作用。体内采用葡聚糖硫酸钠（DSS）诱导 UC 大鼠模型。
UC 患者中 circSOD2 表达上调，其敲低显著增加细胞活力、跨上皮电阻和紧密连接相关蛋白表达，同时降低 LPS 诱导的 Caco2 细胞中炎症细胞因子水平和 FITC-葡聚糖的通透性。就机制而言，circSOD2 可作为 miR-378g 的海绵分子来正向调节 Snail1 的表达。miR-378g 抑制剂可逆转 circSOD2 敲低对 LPS 诱导的 Caco2 细胞中肠道黏膜屏障损伤和 Snail1 表达的影响。在 DSS 诱导的 UC 大鼠模型中，circSOD2 敲低也可通过调节 miR-378g/Snail1 轴来修复肠道黏膜屏障损伤。
circSOD2 可通过 miR-378g/Snail1 轴破坏 LPS 诱导的 Caco2 细胞和 DSS 诱导的 UC 大鼠的肠道黏膜屏障功能。
