雷公藤甲素(TP)是中药雷公藤的主要活性和毒性成份。F.(TWHF),表现出各种治疗生物活性。在毒性作用中,TP的肝毒性值得重视。以前,我们的研究小组提出了TP相关肝毒性的新观点:脂多糖(LPS)刺激下的肝超敏反应.然而,TP/LPS诱导肝超敏反应的机制尚不清楚.在这项研究中,我们从抑制蛋白酶体活性的角度研究了TP/LPS诱导的超敏反应的机制,激活的内质网应激(ERS)相关的凋亡,和活性氧(ROS)的积累。我们的结果表明,N-乙酰半胱氨酸(NAC),一种常见的ROS抑制剂,降低裂解的caspase-3和裂解的PARP的表达,与FLIP增强相关联。此外,4-苯基丁酸(4-PBA),一种ERS抑制剂,能够通过减少ERS相关凋亡蛋白的表达来减轻TP/LPS诱导的肝毒性(GRP78,p-eIF2α/eIF2α,ATF4,CHOP,裂解的caspase-3和裂解的PARP)和ROS水平,ATF4是不可或缺的调解人。此外,蛋白酶体活性抑制剂MG-132进一步加重了ERS相关的细胞凋亡,这表明蛋白酶体活性的抑制在TP/LPS相关的肝损伤中也起着重要作用。总之,我们认为TP/LPS可能通过抑制蛋白酶体活性和通过ATF4增强ROS产生来上调ERS相关凋亡的激活。
Triptolide (TP) is a major active and toxic composition of the Chinese medicine Tripterygium wilfordii Hook. F. (TWHF), exhibiting various therapeutic bioactivities. Among the toxic effects, the hepatotoxicity of TP deserves serious attention. Previously, our research group proposed a new view of TP-related hepatotoxicity: hepatic hypersensitivity under lipopolysaccharide (LPS) stimulation. However, the mechanism of TP/LPS-induced hepatic hypersensitivity remains unclear. In this study, we investigated the mechanism underlying TP/LPS-induced hypersensitivity from the perspective of the inhibition of proteasome activity, activated endoplasmic reticulum stress (ERS)-related apoptosis, and the accumulation of reactive oxygen species (ROS). Our results showed that N-acetylcysteine (NAC), a common ROS inhibitor, decreased the expression of cleaved caspase-3 and cleaved PARP, which are associated with FLIP enhancement. Moreover, 4-phenylbutyric acid (4-PBA), an ERS inhibitor, was able to alleviate TP/LPS-induced hepatotoxicity by reducing ERS-related apoptosis protein expression (GRP78, p-eIF2α/eIF2α, ATF4, CHOP, cleaved caspase-3 and cleaved PARP) and ROS levels, with ATF4 being an indispensable mediator. In addition, the proteasome activity inhibitor MG-132 further aggravated ERS-related apoptosis, which indicated that the inhibition of proteasome activity also plays an important role in TP/LPS-related liver injuries. In summary, we propose that TP/LPS may upregulate the activation of ERS-associated apoptosis by inhibiting proteasome activity and enhancing ROS production through ATF4.