He Xiaoliang, Yuan Rui, Chen Ying, Huang Wenni, Xu Zihao, Wang Bixia, Liu Changhui, Xiong Tianqin
School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, Guangzhou 510006, China.
State Key Laboratory of Traditional Chinese Medicine Syndrome, School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, Guangzhou 510006, China.
Theranostics. 2025 Apr 13;15(11):5258-5276. doi: 10.7150/thno.108593. eCollection 2025.
Valproic acid (VPA), a first-line antiepileptic drug, can induce life-threatening hepatic steatosis with prolonged use; however, the underlying mechanisms remain inadequately elucidated. Nuclear factor E2-related factor 2 (NRF2) is a hepatoprotective factor that maintains redox homeostasis; however, increased levels have been observed in VPA-induced hepatic steatosis. Therefore, the present study aimed to investigate the function of NRF2 in VPA-triggered hepatic steatosis. NRF2 overexpression mice, NRF2 knockout mice, and fatty acid transport protein 2 (FATP2) knockout mice were constructed using adeno-associated virus, homologous recombination, and CRISPR/Cas9 technology, respectively. The mice were then treated with or without oral VPA to induce hepatic steatosis. NRF2 nuclear expression was positively correlated with triglyceride levels in VPA-induced hepatic steatosis. NRF2 overexpression exacerbated VPA-triggered inflammation and steatosis, whereas NRF2 knockout alleviated the effects. Chromatin immunoprecipitation and dual-luciferase reporter gene assay confirmed that FATP2 is a target gene of NRF2. NRF2 exacerbated VPA-induced hepatic steatosis dependent on FATP2. VPA bound to Cys288 and Arg415 of Kelch-like ECH-associated protein 1 (KEAP1), leading to its autophagic degradation and subsequent nuclear translocation of NRF2. Our results revealed a mechanism that VPA binds to specific KEAP1 sites, promoting its degradation and disrupting the KEAP1-NRF2 complex, thereby facilitating NRF2 nuclear translocation. Subsequently, NRF2 activates FATP2 transcription, enhancing fatty acid uptake and contributing to hepatic steatosis. Our findings suggest that inhibiting the NRF2-FATP2 axis could improve VPA-induced hepatic steatosis, offering promising insights into managing drug-induced fatty liver disease.
丙戊酸（VPA）是一种一线抗癫痫药物，长期使用可诱发危及生命的肝脂肪变性；然而，其潜在机制仍未得到充分阐明。核因子E2相关因子2（NRF2）是一种维持氧化还原稳态的肝保护因子；然而，在VPA诱导的肝脂肪变性中已观察到其水平升高。因此，本研究旨在探讨NRF2在VPA引发的肝脂肪变性中的作用。分别使用腺相关病毒、同源重组和CRISPR/Cas9技术构建了NRF2过表达小鼠、NRF2基因敲除小鼠和脂肪酸转运蛋白2（FATP2）基因敲除小鼠。然后对小鼠进行口服VPA或不进行口服VPA处理以诱导肝脂肪变性。在VPA诱导的肝脂肪变性中，NRF2的核表达与甘油三酯水平呈正相关。NRF2过表达加剧了VPA引发的炎症和脂肪变性，而NRF2基因敲除则减轻了这些影响。染色质免疫沉淀和双荧光素酶报告基因检测证实FATP2是NRF2的靶基因。NRF2依赖FATP2加剧了VPA诱导的肝脂肪变性。VPA与 Kelch样ECH相关蛋白1（KEAP1）的半胱氨酸288和精氨酸415结合，导致其自噬降解以及随后NRF2的核转位。我们的结果揭示了一种机制，即VPA与特定的KEAP1位点结合，促进其降解并破坏KEAP1-NRF2复合物，从而促进NRF2的核转位。随后，NRF2激活FATP2转录，增强脂肪酸摄取并导致肝脂肪变性。我们的研究结果表明，抑制NRF2-FATP2轴可以改善VPA诱导的肝脂肪变性，为药物性脂肪肝疾病的管理提供了有前景的见解。
