Guangdong Engineering Research Center of Chinese Medicine & Disease Susceptibility, Jinan University, 510632, Guangzhou, China.
Department of Pharmacy, Hainan General Hospital (Hainan Affiliated Hospital of Hainan Medical University), 570311, Haikou, Hainan, China.
Cell Death Dis. 2020 Sep 19;11(9):781. doi: 10.1038/s41419-020-02961-5.
Drug-induced liver injury is the major cause of acute liver failure. However, the underlying mechanisms seem to be multifaceted and remain poorly understood, resulting in few effective therapies. Here, we report a novel mechanism that contributes to acetaminophen-induced hepatotoxicity through the induction of ferroptosis, a distinctive form of programmed cell death. We subsequently identified therapies protective against acetaminophen-induced liver damage and found that (+)-clausenamide ((+)-CLA), an active alkaloid isolated from the leaves of Clausena lansium (Lour.) Skeels, inhibited acetaminophen-induced hepatocyte ferroptosis both in vivo and in vitro. Consistently, (+)-CLA significantly alleviated acetaminophen-induced or erastin-induced hepatic pathological damages, hepatic dysfunctions and excessive production of lipid peroxidation both in cultured hepatic cell lines and mouse liver. Furthermore, treatment with (+)-CLA reduced the mRNA level of prostaglandin endoperoxide synthase 2 while it increased the protein level of glutathione peroxidase 4 in hepatocytes and mouse liver, confirming that the inhibition of ferroptosis contributes to the protective effect of (+)-CLA on drug-induced liver damage. We further revealed that (+)-CLA specifically reacted with the Cys-151 residue of Keap1, which blocked Nrf2 ubiquitylation and resulted in an increased Nrf2 stability, thereby leading to the activation of the Keap1-Nrf2 pathway to prevent drug-induced hepatocyte ferroptosis. Our studies illustrate the innovative mechanisms of acetaminophen-induced liver damage and present a novel intervention strategy to treat drug overdose by using (+)-CLA.
药物性肝损伤是急性肝衰竭的主要原因。然而，其潜在机制似乎是多方面的，目前仍了解甚少，导致有效的治疗方法很少。在这里，我们报告了一种新的机制，即通过诱导铁死亡（一种独特的程序性细胞死亡形式）导致对乙酰氨基酚引起的肝毒性。随后，我们确定了针对对乙酰氨基酚引起的肝损伤的治疗方法，并发现从芸香科吴茱萸属植物（吴茱萸）叶片中分离出的活性生物碱(+)-clausenamide((+)-CLA)可在体内和体外抑制对乙酰氨基酚诱导的肝细胞铁死亡。一致地，(+)-CLA 显著缓解了在培养的肝细胞系和小鼠肝脏中由对乙酰氨基酚或 erastin 诱导的肝病理损伤、肝功能障碍和脂质过氧化的过度产生。此外，(+)-CLA 的治疗降低了前列腺素内过氧化物合酶 2 的 mRNA 水平，同时增加了肝细胞和小鼠肝脏中谷胱甘肽过氧化物酶 4 的蛋白水平，证实了铁死亡的抑制有助于 (+)-CLA 对药物性肝损伤的保护作用。我们进一步揭示(+)-CLA 特异性地与 Keap1 的 Cys-151 残基反应，阻止 Nrf2 泛素化并导致 Nrf2 稳定性增加，从而导致 Keap1-Nrf2 通路的激活，以防止药物诱导的肝细胞铁死亡。我们的研究说明了对乙酰氨基酚引起的肝损伤的创新机制，并提出了一种使用(+)-CLA 治疗药物过量的新干预策略。
