Atractylodin induces programmed necrosis of non-small cell lung cancer A549 cells and inhibits xenograft growth in nude mice by activating the RIPK1/RIPK3/MLKL signaling pathway / 中国肿瘤生物治疗杂志

@#目的：探讨苍术素（ATR）通过调节受体相互作用蛋白激酶（RIPK）1/RIPK3/混合谱系激酶结构域样（MLKL）信号通路对非小细胞肺癌（NSCLC）A549细胞程序性死亡及裸鼠移植瘤生长的影响。方法：使用0~160 μmol/L的ATR处理A549细胞，MTT法检测细胞存活率以确定后续实验给药浓度。使用ATR和/或RIPK1抑制剂Nec-1（necrostatin-1）、caspase抑制剂Z-VAD-FMK处理A549细胞，验证ATR是否诱导A549细胞发生程序性坏死。将A549细胞分为对照组、ATR-L组、ATR-M组、ATR-H组（分别用0、10、20、40 μmol/L ATR处理）、ATR+Nec-1组（40 μmol/L ATR+50 μmol/L Nec-1处理），处理24 h后，采用PI单染及Hoechst33342/PI双染法检测细胞死亡情况、透射电镜观察细胞死亡形态、DCFH-DA荧光探针法检测细胞内ROS水平、JC-1染色法检测线粒体膜电位、WB法检测细胞中RIPK1/RIPK3/MLKL信号通路相关蛋白质的表达水平。构建A549细胞裸鼠移植瘤模型，用10 mg/kg ATR（溶于玉米油中）对裸鼠灌胃给药5周，观察ATR对移植瘤生长的影响，WB法检测移植瘤组织中RIPK1/RIPK3/MLKL信号通路相关蛋白质的表达水平。结果：10~160 μmol/L的ATR可显著抑制A549细胞增殖，选择10、20、40 μmol/L的ATR进行后续实验。ATR组A549细胞存活率显著低于对照组（P<0.01）和ATR+Nec-1组（P<0.01），而ATR+z-VAD组细胞存活率显著低于z-VAD组（P<0.01），说明ATR可诱导A549细胞发生程序性坏死而非凋亡。与对照组比较，ATR处理组A549细胞发生肿胀，线粒体内脊消失呈空泡化，细胞内容物向外泄漏，细胞核聚集，表现为坏死特征，ATR-L组、ATR-M组、ATR-H组A549细胞死亡率、ROS水平及p-RIPK1、p-RIPK3、p-MLKL表达水平均显著升高，线粒体膜电位显著降低（均P<0.01），且呈药物浓度依赖性；与ATR-H组比较，ATR+Nec-1组细胞死亡率、ROS及p-RIPK1、p-RIPK3、p-MLKL表达水平降低，线粒体膜电位显著升高（均P<0.01）。裸鼠移植瘤实验结果显示，与对照组比较，ATR组裸鼠移植瘤体积、移植瘤质量均降低（P<0.05，或P<0.01），而与瘤组织中p-RIPK1、p-RIPK3、p-MLKL蛋白表达水平均显著升高（均P<0.01）。结论：ATR可能通过激活RIPK1/RIPK3/MLKL信号通路诱导A549细胞发生程序性坏死，抑制A549细胞及其裸鼠移植瘤的生长。

Structure-based development of potent and selective type-II kinase inhibitors of RIPK1

Receptor-interacting serine/threonine-protein kinase 1 (RIPK1) functions as a key regulator in inflammation and cell death and is involved in mediating a variety of inflammatory or degenerative diseases. A number of allosteric RIPK1 inhibitors (RIPK1i) have been developed, and some of them have already advanced into clinical evaluation. Recently, selective RIPK1i that interact with both the allosteric pocket and the ATP-binding site of RIPK1 have started to emerge. Here, we report the rational development of a new series of type-II RIPK1i based on the rediscovery of a reported but mechanistically atypical RIPK3i. We also describe the structure-guided lead optimization of a potent, selective, and orally bioavailable RIPK1i, 62, which exhibits extraordinary efficacies in mouse models of acute or chronic inflammatory diseases. Collectively, 62 provides a useful tool for evaluating RIPK1 in animal disease models and a promising lead for further drug development.

Effects and mechanisms of total flavones of Abelmoschus manihot in inhibiting podocyte necroptosis and renal fibrosis in diabetic kidney disease / 中国中药杂志

Previous studies have shown that high blood glucose-induced chronic microinflammation can cause inflammatory podocyte injury in patients with diabetic kidney disease(DKD). Therein, necroptosis is a new form of podocyte death that is closely associated with renal fibrosis(RF). To explore the effects and mechanisms in vivo of total flavones of Abelmoschus manihot(TFA), an extract from traditional Chinese herbal medicine Abelmoschus manihot for treating kidney diseases, on podocyte necroptosis and RF in DKD, and to further reveal its scientific connotation with multi-pathway and multi-target, the authors randomly divided all rats into four groups: a namely normal group, a model group, a TFA group and a rapamycin(RAP) group. After the modified DKD rat models were successfully established, four group rats were given double-distilled water, TFA suspension and RAP suspension, respectively by gavage every day. At the end of the 4th week of drug treatment, all rats were sacrificed, and the samples of their urine, blood and kidneys were collected. And then, the various indicators related to podocyte necroptosis and RF in the DKD model rats were observed, detected and analyzed, respectively. The results indicated that, general condition, body weight(BW), serum creatinine(Scr), urinary albumin(UAlb), and kidney hypertrophy index(KHI) in these modified DKD model rats were both improved by TFA and RAP. Indicators of RF, including glomerular histomorphological characteristics, fibronectin(FN) and collagen type Ⅰ(collagen Ⅰ) staining extent in glomeruli, as well as the protein expression levels of FN, collagen Ⅰ, transforming growth factor-β1(TGF-β1) and Smad2/3 in the kidneys were improved respectively by TFA and RAP. Podocyte damage, including foot process form and the protein expression levels of podocin and CD2AP in the kidneys was improved by TFA and RAP. In addition, tumor necrosis factor-α(TNF-α)-mediated podocyte necroptosis in the kidneys, including the morphological characteristics of podocyte necroptosis, the extent and levels of the protein expression of TNF-α and phosphorylated mixed lineage kinase domain like pseudokinase(p-MLKL) was improved respectively by TFA and RAP. Among them, RAP had the better effect on p-MLKL. More importantly, the activation of the receptor interacting serine/threonine protein kinase 1(RIPK1)/RIPK3/MLKL signaling axis in the kidneys, including the expression levels of its key signaling molecules, such as phosphorylated receptor interacting serine/threonine protein kinase 1(p-RIPK1), p-RIPK3, p-MLKL and cysteinyl aspartate specific proteinase-8(caspase-8) was improved respectively by TFA and RAP. Among them, the effect of TFA on p-RIPK1 was superior. On the whole, in this study, the authors demonstrated that TFA alleviates podocyte necroptosis and RF in DKD through inhibiting the activation of the TNF-α-mediated RIPK1/RIPK3/MLKL signaling axis in diabetic kidneys. The authors' findings provide new pharmacological evidence to reveal the scientific connotation of TFA in treating RF in DKD in more depth.