Liang Qi-Qi, Shi Zi-Jian, Yuan Tao, Chen Si-Yuan, Li Ya-Ping, Zhang Hong-Rui, You Yi-Ping, Xu Rong, Xu Li-Hui, Hu Bo, Ouyang Dong-Yun, Zha Qing-Bing, He Xian-Hui
Department of Immunobiology, College of Life Science and Technology, Jinan University, Guangzhou 510632, China.
Department of Fetal Medicine, The First Affiliated Hospital of Jinan University, Guangzhou 510630, China.
Int Immunopharmacol. 2023 Apr;117:109974. doi: 10.1016/j.intimp.2023.109974. Epub 2023 Mar 8.
Necroptosis is a necrotic form of regulated cell death, which is primarily mediated by the receptor-interacting protein kinase 1 (RIPK1), RIPK3, and mixed lineage kinase domain-like (MLKL) pathway in a caspase-independent manner. Necroptosis has been found to occur in virtually all tissues and diseases evaluated, including pancreatitis. Celastrol, a pentacyclic triterpene extracted from the roots of Tripterygium wilfordii (thunder god vine), possesses potent anti-inflammatory and anti-oxidative activities. Yet, it is unclear whether celastrol has any effects on necroptosis and necroptotic-related diseases. Here we showed that celastrol significantly suppressed necroptosis induced by lipopolysaccharide (LPS) plus pan-caspase inhibitor (IDN-6556) or by tumor-necrosis factor-α in combination with LCL-161 (Smac mimetic) and IDN-6556 (TSI). In these in vitro cellular models, celastrol inhibited the phosphorylation of RIPK1, RIPK3, and MLKL and the formation of necrosome during necroptotic induction, suggesting its possible action on upstream signaling of the necroptotic pathway. Consistent with the known role of mitochondrial dysfunction in necroptosis, we found that celastrol significantly rescued TSI-induced loss of mitochondrial membrane potential. TSI-induced intracellular and mitochondrial reactive oxygen species (mtROS), which are involved in the autophosphorylation of RIPK1 and recruitment of RIPK3, were significantly attenuated by celastrol. Moreover, in a mouse model of acute pancreatitis that is associated with necroptosis, celastrol administration significantly reduced the severity of caerulein-induced acute pancreatitis accompanied by decreased phosphorylation of MLKL in pancreatic tissues. Collectively, celastrol can attenuate the activation of RIPK1/RIPK3/MLKL signaling likely by attenuating mtROS production, thereby inhibiting necroptosis and conferring protection against caerulein-induced pancreatitis in mice.
坏死性凋亡是一种受调控的细胞死亡的坏死形式，主要由受体相互作用蛋白激酶1（RIPK1）、RIPK3和混合谱系激酶结构域样蛋白（MLKL）通路以不依赖半胱天冬酶的方式介导。已发现坏死性凋亡几乎在所有评估的组织和疾病中都会发生，包括胰腺炎。雷公藤红素是从雷公藤根中提取的一种五环三萜，具有强大的抗炎和抗氧化活性。然而，尚不清楚雷公藤红素是否对坏死性凋亡及与坏死性凋亡相关的疾病有任何影响。在此我们表明，雷公藤红素显著抑制脂多糖（LPS）加泛半胱天冬酶抑制剂（IDN-6556）或肿瘤坏死因子-α联合LCL-161（Smac模拟物）和IDN-6556（TSI）诱导的坏死性凋亡。在这些体外细胞模型中，雷公藤红素在坏死性凋亡诱导过程中抑制RIPK1、RIPK3和MLKL的磷酸化以及坏死小体的形成，表明其可能作用于坏死性凋亡通路的上游信号。与线粒体功能障碍在坏死性凋亡中的已知作用一致，我们发现雷公藤红素显著挽救了TSI诱导的线粒体膜电位丧失。TSI诱导的参与RIPK1自磷酸化和RIPK3募集的细胞内和线粒体活性氧（mtROS）被雷公藤红素显著减弱。此外，在与坏死性凋亡相关的急性胰腺炎小鼠模型中，给予雷公藤红素显著降低了雨蛙肽诱导的急性胰腺炎的严重程度，同时胰腺组织中MLKL的磷酸化减少。总体而言，雷公藤红素可能通过减弱mtROS的产生来减弱RIPK1/RIPK3/MLKL信号的激活，从而抑制坏死性凋亡并对小鼠雨蛙肽诱导的胰腺炎提供保护。
