Inhibition of ferroptosis in intestinal epithelial cells serves as an attractive target for the development of therapeutic strategies for colitis. Pinobanksin, one of the main flavonoids derived from propolis, possesses significant anti-inflammatory effects and inhibits the cell death of several cell lines. Here, we evaluated whether pinobanksin influenced colitis by modulation of epithelial ferroptosis. Mice treated with 2.5% DSS dissolved in sterile distilled water were established for an acute colitis model. The mitochondrial morphology, colonic iron level, lipid peroxidation products MDA/4-HNE, and lipid reactive oxygen species levels were measured to assess ferroptosis in epithelial cells. RNA-seq and functional analyses were performed to reveal key genes mediating pinobanksin-exerted modulation of ferroptosis. We found that pinobanksin, at different doses, induced significant anti-colitis effects and inhibited the elevated ferroptosis in colonic epithelial cells isolated from DSS-treated mice largely by activating GPX4 (negative regulator of ferroptosis). Furthermore, RNA-seq assays indicated that pinobanksin significantly increased the cystine transporter SLC7A11 in colonic tissues from mice with colitis. Depletion of SLC7A11 largely blocked pinobanksin-induced promotion of cystine uptake/glutathione biosynthesis and suppression of ferroptosis in epithelial cells from mice with colitis or IEC-6 cells pretreated with RSL3. Altogether, pinobanksin alleviated DSS-induced colitis largely by inhibition of ferroptosis in epithelial cells. Activation of SLC7A11 by pinobanksin resulted in the promotion of cystine uptake and enhancement of glutathione biosynthesis. This work will provide novel guidance for the clinical use of pinobanksin to treat colitis through inhibition of epithelial ferroptosis.

中文翻译：

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Pinobanksin 主要通过调节 SLC7A11/谷胱甘肽介导的肠上皮铁死亡来改善 DSS 诱导的急性结肠炎

抑制肠上皮细胞中的铁死亡是开发结肠炎治疗策略的一个有吸引力的目标。 Pinobanksin 是从蜂胶中提取的主要黄酮类化合物之一，具有显着的抗炎作用并抑制多种细胞系的细胞死亡。在这里，我们评估了 pinobanksin 是否通过调节上皮铁死亡来影响结肠炎。用溶解在无菌蒸馏水中的2.5％DSS处理小鼠建立急性结肠炎模型。测量线粒体形态、结肠铁水平、脂质过氧化产物 MDA/4-HNE 和脂质活性氧水平，以评估上皮细胞铁死亡情况。 RNA-seq 和功能分析揭示了介导 pinobanksin 调节铁死亡的关键基因。我们发现，不同剂量的pinobanksin可诱导显着的抗结肠炎作用，并在很大程度上通过激活GPX4（铁死亡负调节因子）来抑制从DSS处理的小鼠中分离的结肠上皮细胞中升高的铁死亡。此外，RNA-seq 检测表明，pinobanksin 显着增加结肠炎小鼠结肠组织中的胱氨酸转运蛋白 SLC7A11。 SLC7A11的耗尽在很大程度上阻断了pinobanksin诱导的胱氨酸摄取/谷胱甘肽生物合成的促进以及结肠炎小鼠上皮细胞或经RSL3预处理的IEC-6细胞中铁死亡的抑制。总而言之，pinobanksin 主要通过抑制上皮细胞铁死亡来缓解 DSS 诱导的结肠炎。 pinobanksin 激活 SLC7A11 可促进胱氨酸的摄取并增强谷胱甘肽的生物合成。这项工作将为临床使用pinobanksin通过抑制上皮铁死亡来治疗结肠炎提供新的指导。