Background

Excessive extracellular matrix (ECM) deposition leads to renal fibrosis, a typical hallmark of chronic kidney disease. Liquiritin is a flavonoid extracted from the rhizome part of Glycyrrhiza glabra and has anti-fibrotic and nephroprotective effects. However, its role and underlying mechanism in renal fibrosis remain unknown.

Methods

Human renal proximal tubular epithelial cells (HRPTEpiCs) were stimulated with 10 ng/mL TGF-β1 to induce renal fibrosis models in vitro. The morphology of HRPTEpiCs was observed under a light microscope. CCK-8 was utilized to test cell viability. Immunofluorescence staining was conducted to measure α-SMA expression in HRPTEpiCs. RT-qPCR was used to assess relative mRNA expression. The protein levels of ECM markers, epithelial mesenchymal transition (EMT) markers, and MAPK signaling-related molecules in HRPTEpiCs were tested using western blotting.

Results

TGF-β1-treated HRPTEpiCs showed a fibroblast-like morphology, and the morphology of HRPTEpiCs was restored by liquiritin. Liquiritin suppressed TGF-β1-stimulated ECM deposition and EMT process in HRPTEpiCs. Additionally, liquiritin repressed TGF-β1-induced MAPK signaling activation in HRPTEpiCs.

Conclusion

Liquiritin mitigates TGF-β1-triggered EMT process and ECM deposition in HRPTEpiCs by inactivating MAPK signaling, thus preventing renal fibrosis.

中文翻译：

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甘草苷通过抑制 MAPK 信号传导抑制 TGF-β1 诱导的人肾近端肾小管上皮细胞上皮间质转化和细胞外基质沉积

背景

过多的细胞外基质（ECM）沉积导致肾纤维化，这是慢性肾病的典型特征。甘草苷是从光果甘草的根茎部分中提取的黄酮类化合物，具有抗纤维化和肾保护作用。然而，其在肾纤维化中的作用和潜在机制仍不清楚。

方法

用 10 ng/mL TGF-β1 刺激人肾近端肾小管上皮细胞 (HRPTEpiC)，在体外诱导肾纤维化模型。在光学显微镜下观察HRPTEpiCs的形态。CCK-8用于测试细胞活力。进行免疫荧光染色来测量 HRPTEpiC 中 α-SMA 的表达。RT-qPCR 用于评估相对 mRNA 表达。使用蛋白质印迹法测试 HRPTEpiC 中 ECM 标记物、上皮间质转化 (EMT) 标记物和 MAPK 信号相关分子的蛋白水平。

结果

TGF-β1处理的HRPTEpiCs呈现出成纤维细胞样的形态，并且甘草苷可以恢复HRPTEpiCs的形态。甘草苷抑制 HRPTEpiC 中 TGF-β1 刺激的 ECM 沉积和 EMT 过程。此外，甘草苷还可抑制 HRPTEpiC 中 TGF-β1 诱导的 MAPK 信号激活。

结论

甘草苷通过灭活 MAPK 信号传导来减轻 TGF-β1 触发的 EMT 过程和 ECM 在 HRPTEpiC 中的沉积，从而预防肾纤维化。