Sun Ping, Yang Haihui, Min Binying, Li Yongfu, Wang Jun, Chen Mo, Yu Diping, Sun Wenjuan
Ministry of Science and Education, Pu'er People's Hospital, Pu'er, Yunnan, China.
Ministry of Science and Education, Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, Yunnan, China.
Biochem Biophys Rep. 2024 Dec 26;41:101907. doi: 10.1016/j.bbrep.2024.101907. eCollection 2025 Mar.
Chronic kidney disease (CKD) has become a worldwide health problem and the incidence rate and mortality of CKD have been rising. Renal fibrosis (RF) is the final common pathological feature of almost all kinds of CKD and Epithelial-mesenchymal transition (EMT) is the predominant stage of RF. β-catenin is a key component of the Wnt signaling pathway, which has been fully proven to promote EMT. However, the underlying mechanism of β-catenin in EMT during the pathogenesis of RF is yet to be determined.
This study was designed to investigate the effects of β-catenin on RF-related EMT and further investigate its underlying mechanism.
Human proximal tubular epithelial cell (HK-2) was treated with hypoxia to construct RF injury cell model. The viability of cells was determined by CCK-8 assay. Immunofluorescence was used to detect α-SMA content. Expressions of β-catenin, Brachyury and RF-related proteins were measured by Western blot. The correlation between β-catenin and Brachyury was detected by ChIP-qPCR and dual luciferase reporter assay.
We found β-catenin was overexpressed in hypoxia-induced HK-2 cells. In the RF cell model, silencing of β-catenin weakened the EMT and fibrogenesis activity of HK-2 cells. Mechanistically, we found β-catenin binds to T-cell factor (TCF) to activate Brachyury, which is a positive player in EMT. Further studies clarified that Brachyury was responsible for β-catenin-promoted the EMT and HK-2 cell injury under hypoxia condition.
Herein, we demonstrated that β-catenin is overexpressed in hypoxia-induced HK-2 cells and promotes EMT and cell injury via activating Brachyury. These findings suggest that targeting β-catenin/Brachyury may be an effective new approach for treating RF.
慢性肾脏病（CKD）已成为一个全球性的健康问题，其发病率和死亡率一直在上升。肾纤维化（RF）是几乎所有类型CKD的最终共同病理特征，上皮-间质转化（EMT）是RF的主要阶段。β-连环蛋白是Wnt信号通路的关键组成部分，已充分证明其可促进EMT。然而，β-连环蛋白在RF发病机制中EMT过程中的潜在机制尚待确定。
本研究旨在探讨β-连环蛋白对RF相关EMT的影响，并进一步研究其潜在机制。
用缺氧处理人近端肾小管上皮细胞（HK-2）构建RF损伤细胞模型。采用CCK-8法检测细胞活力。免疫荧光法检测α-SMA含量。采用蛋白质免疫印迹法检测β-连环蛋白、Brachyury及RF相关蛋白的表达。通过染色质免疫沉淀-定量聚合酶链反应（ChIP-qPCR）和双荧光素酶报告基因检测法检测β-连环蛋白与Brachyury之间的相关性。
我们发现β-连环蛋白在缺氧诱导的HK-2细胞中过表达。在RF细胞模型中，沉默β-连环蛋白可减弱HK-2细胞的EMT和纤维化活性。机制上，我们发现β-连环蛋白与T细胞因子（TCF）结合以激活Brachyury，后者是EMT中的一个积极参与者。进一步研究表明，在缺氧条件下，Brachyury是β-连环蛋白促进EMT和HK-2细胞损伤的原因。
在此，我们证明β-连环蛋白在缺氧诱导的HK-2细胞中过表达，并通过激活Brachyury促进EMT和细胞损伤。这些发现表明，靶向β-连环蛋白/Brachyury可能是治疗RF的一种有效的新方法。
