Department of Gastroenterology, Renmin Hospital of Wuhan University, Wuhan, 430060, Hubei Province, China.
Department of Oncology, Renmin Hospital of Wuhan University, Wuhan, 430060, Hubei Province, China.
Eur J Pharmacol. 2020 Apr 15;873:172992. doi: 10.1016/j.ejphar.2020.172992. Epub 2020 Feb 6.
Hesperetin, a flavonoid from citrus fruits, possess various pharmacological properties, including anti-inflammatory, anti-oxidative, anti-tumor potentials. However, the role and its mechanism in ulcerative colitis (UC) remains unclear. This study aimed to investigate the protective effects and mechanisms of hesperetin on dextran sodium sulfate (DSS) -induced colitis. Our results showed that hesperetin significantly relieved the symptoms of DSS -induced colitis and increased the expressions of zonula occludens-1 (ZO-1), occludin and mucin2 (MUC-2) as well as the decrease of tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, IL-18, HMGB1 and IL-6. Of note, results from immunohistochemistry (IHC) and western blotting indicated that hesperetin inhibited the expressions of receptor-interacting protein kinase 3 (RIPK3) and mixed lineage kinase domain-like (MLKL), the two key proteins of necroptosis pathway, and inactivated RIPK3/MLKL necroptosis signalling. Meanwhile, in the cell-coculture system between Caco-2 and RAW264.7 cells, hesperetin treatment significantly ameliorated the decrease of trans epithelial electric resistance (TEER) value while HS-173 (necroptosis inducer) could obviously influence the effect of hesperetin. In addition, hesperetin attenuated the LPS-induced increasing in 4-kDa fluorescein isothiocyanate-dextran (FD4) permeability while HS-173 could weaken the protective effect of hesperetin. Meanwhile, HS-173 reduced the changes in the expressions of phosphorylated RIPK3, phosphorylated MLKL, ZO-1, occludin and MUC-2 as well as TNF-α, IL-1β. These findings demonstrated hesperetin ameliorated DSS-induced colitis by maintaining the epithelial barrier via blocking the intestinal epithelial necroptosis.
橙皮素是一种来自柑橘类水果的类黄酮，具有多种药理特性，包括抗炎、抗氧化、抗肿瘤潜力。然而，其在溃疡性结肠炎（UC）中的作用和机制尚不清楚。本研究旨在探讨橙皮素对葡聚糖硫酸钠（DSS）诱导的结肠炎的保护作用及其机制。我们的结果表明，橙皮素能显著缓解 DSS 诱导的结肠炎症状，增加紧密连接蛋白-1（ZO-1）、闭合蛋白和粘蛋白 2（MUC-2）的表达，减少肿瘤坏死因子-α（TNF-α）、白细胞介素（IL）-1β、IL-18、高迁移率族蛋白 B1（HMGB1）和白细胞介素 6（IL-6）的表达。值得注意的是，免疫组化（IHC）和蛋白质印迹结果表明，橙皮素抑制了受体相互作用蛋白激酶 3（RIPK3）和混合谱系激酶结构域样（MLKL）的表达，这两种坏死通路的关键蛋白，并且抑制了 RIPK3/MLKL 坏死信号通路。同时，在 Caco-2 和 RAW264.7 细胞的细胞共培养系统中，橙皮素处理显著改善了跨上皮电阻（TEER）值的降低，而 HS-173（坏死诱导剂）可明显影响橙皮素的作用。此外，橙皮素可减弱脂多糖诱导的 4- kDa 荧光素异硫氰酸酯右旋糖苷（FD4）通透性增加，而 HS-173 可减弱橙皮素的保护作用。同时，HS-173 降低了磷酸化 RIPK3、磷酸化 MLKL、ZO-1、闭合蛋白和 MUC-2 以及 TNF-α、IL-1β的表达变化。这些结果表明，橙皮素通过阻断肠道上皮细胞坏死来改善 DSS 诱导的结肠炎，从而维持上皮屏障。
