雷公藤甲素(TP),雷公藤的主要活性成分,广泛用于治疗炎症和自身免疫性疾病。其临床应用受到严重不良反应的限制,尤其是心脏毒性.越来越多的证据表明TP通过抑制RNA聚合酶诱导DNA损伤。考虑到DNA损伤之间的关系,p53和p53在线粒体依赖性凋亡中的作用,我们推测TP诱导的心脏毒性是p53激活的结果.在这项研究中,在H9c2细胞中研究了p53在TP诱导的心脏毒性中的作用,原代心肌细胞,和C57BL/6遗传背景p53-/-小鼠。在体外和急性心脏损伤模型中,TP升高了p53蛋白水平。TP给药(1.2mg/kg),p53缺乏可预防心脏组织学损伤,并降低血清心肌肌钙蛋白I(cTn-I)和凋亡蛋白。机械上,免疫印迹和免疫荧光染色确定TP诱导的毒性依赖于p53核易位和Bcl2家族基因的反式激活,导致线粒体外膜透化(MOMP)和线粒体功能障碍。始终如一,p53拮抗剂PFTα对抗TP诱导的p53过表达和Bcl2家族转录的调节,改善线粒体膜完整性并防止细胞凋亡。此外,Bax拮抗剂Bax抑制剂肽(BIP)V5通过抑制膜去极化和ROS积累来改善TP诱导的细胞凋亡。这些结果表明,TP诱导的心脏毒性通过促进Bax诱导的线粒体介导的细胞凋亡而依赖于p53。
Triptolide (TP), a major active component of Tripterygium wilfordii Hook f., is widely used in the treatment of inflammation and autoimmune disorders. Its clinical application is limited by severe adverse effects, especially cardiotoxicity. Accumulative evidences indicate that TP induces DNA damage by inhibiting RNA polymerase. Considering the relationship among DNA damage, p53, and the role of p53 in mitochondria-dependent apoptosis, we speculate that TP-induced cardiotoxicity results from p53 activation. In this study, the role of p53 in TP-induced cardiotoxicity was investigated in H9c2 cells, primary cardiomyocytes, and C57BL/6 genetic background p53-/- mice. p53 protein level was elevated by TP in vitro and in acute heart injury models. With TP administration (1.2 mg/kg), p53 deficiency prevented heart histology injury and decreased serum cardiac troponin I (cTn-I) and apoptotic proteins. Mechanistically, immunoblotting and immunofluorescence staining identified that TP-induced toxicity is dependent on p53 nuclear translocation and transactivation of Bcl2 family genes, leading to mitochondrial outer membrane permeabilization (MOMP) and mitochondria dysfunction. Consistently, p53 antagonist PFTα counteracted TP-induced p53 overexpression and regulation of Bcl2 family transcription, which improved mitochondrial membrane integrity and prevented apoptosis. Moreover, Bax antagonist Bax inhibitor peptide (BIP) V5 ameliorated TP-induced apoptosis through suppressing membrane depolarization and ROS accumulation. These results suggest that TP-induced cardiotoxicity is p53-dependent by promoting Bax-induced mitochondria-mediated apoptosis.