Wu Tong, Liu Yan, Ma Jiyuan, Lu Lingshan, Wang Liang, He Mengmei, Hao Zhuang, Liu Xiaomin, Zhang Luning, Zhao Chao, Tao Mengzhang, Zheng Chao, Zhou Jian
Department of Ophthalmology, Xijing Hospital, Eye Institute of Chinese PLA, Fourth Military Medical University, 710032 Xi'an, China.
State Key Laboratory of Cancer Biology, Department of Medical Genetics and Developmental Biology, Fourth Military Medical University, 710032 Xi'an, China.
Theranostics. 2025 Jul 11;15(16):7940-7955. doi: 10.7150/thno.109442. eCollection 2025.
The epithelial‒mesenchymal transition (EMT) decisively contributes to human diseases such as organ fibrosis and tumors. However, the molecular mechanism triggering EMT remains unclear. We elucidated a novel self-amplifying feedback loop involving activating transcription factor 6 (ATF6) and Snail family transcriptional repressor 1 (SNAI1) and assessed its significant role in unfolded protein response (UPR)-dependent EMT. Multiple and models were applied, including mouse models of trauma and laser-induced lens injury and human lens epithelial explants from patients with senile cataracts. RNA sequencing was performed to comprehensively analyze the molecular mechanisms underlying UPR-dependent EMT, and heterozygous knockout mice provided insights into the UPR-EMT crosstalk. The direct interaction between ATF6 and SNAI1 was verified via dual-luciferase assays. ATF6 expression was inhibited using AAV-shATF6 and melatonin (MLT) treatment in rodent models and cell cultures, respectively. Slit-lamp imaging, immunostaining, and western blotting were performed to assess EMT inhibition. ATF6 expression was markedly upregulated in fibrotic cataracts, and overexpression was sufficient to induce EMT-like changes both and . Similarly, compared with wild-type control mice, heterozygous knockout mice presented ameliorated injury-induced EMT. Dual-luciferase assays combined with functional studies revealed a self-amplifying loop between ATF6 and that drives the uncontrollable progression of UPR-dependent EMT. Notably, MLT emerged as an effective inhibitor of UPR-dependent EMT and mitigated EMT-like alterations in parallel with knockdown, suggesting that MLT could be leveraged to target the ATF6-SNAI1 self-amplifying loop and inhibit EMT in human diseases. Collectively, the results of this work demonstrate that the ATF6-SNAI1 self-amplifying loop acts as an important mediator of EMT and that MLT could be leveraged to target this loop and inhibit EMT in lens fibrosis.
上皮-间质转化（EMT）在诸如器官纤维化和肿瘤等人类疾病中起决定性作用。然而，触发EMT的分子机制仍不清楚。我们阐明了一种涉及激活转录因子6（ATF6）和蜗牛家族转录抑制因子1（SNAI1）的新型自我放大反馈环，并评估了其在未折叠蛋白反应（UPR）依赖性EMT中的重要作用。应用了多种模型，包括创伤和激光诱导晶状体损伤的小鼠模型以及来自老年性白内障患者的人晶状体上皮外植体。进行RNA测序以全面分析UPR依赖性EMT的分子机制，杂合敲除小鼠为UPR-EMT串扰提供了见解。通过双荧光素酶测定验证了ATF6和SNAI1之间的直接相互作用。在啮齿动物模型和细胞培养中分别使用AAV-shATF6和褪黑素（MLT）处理抑制ATF6表达。进行裂隙灯成像、免疫染色和蛋白质印迹以评估EMT抑制情况。在纤维化白内障中，ATF6表达明显上调，并且其过表达足以在体内和体外诱导类似EMT的变化。同样，与野生型对照小鼠相比，杂合敲除小鼠的损伤诱导EMT有所改善。双荧光素酶测定与功能研究相结合揭示ATF6和SNAI1之间存在一个自我放大环，驱动UPR依赖性EMT的不可控进展。值得注意的是，MLT是UPR依赖性EMT的有效抑制剂，与ATF6敲低同时减轻了类似EMT的改变，表明MLT可用于靶向ATF6-SNAI1自我放大环并抑制人类疾病中的EMT。总体而言，这项工作的结果表明，ATF6-SNAI1自我放大环是EMT的重要介质，并且MLT可用于靶向该环并抑制晶状体纤维化中的EMT。
