SP600125对D-氨基葡萄糖衍生物诱导Eca-109细胞凋亡的影响

目的:观察特异性JNK抑制剂[specificc-junNH2terminalproteinkinase(JNK)inhibitor]SP600125对D-氨基葡萄糖衍生物2-(3-羧基-1-丙酰氨基)-2-脱氧-D-葡萄糖{[2-(3-carboxy-1-oxopropyl)a-mino-2-deoxy-D-Glucose],COPADG}诱导Eca-109细胞凋亡的影响并探讨COPADG诱导Eca-109细胞凋亡的潜在分子机制。方法:体外培养Eca-109细胞,用COPADG及SP600125对细胞进行处理。细胞间接免疫荧光染色观察P-JNK蛋白表达的改变,倒置相差显微镜观察细胞形态学变化;MTT检测不同时间点的细胞活性;流式细胞术检测细胞凋亡率。结果:经SP600125处理后,COPADG诱导的Eca-109细胞P-JNK蛋白表达明显减弱,同时,COPADG诱导的Eca-109细胞凋亡率明显减低,细胞增殖抑制率下降明显,与COPADG单独作用组之间比较差异有统计学意义。结论:SP600125对D-氨基葡萄糖衍生物CO-PADG诱导Eca-109细胞凋亡具有抑制作用,并间接证明JNK信号转导通路在COPADG诱导Eca-109细胞凋亡过程中发挥着重要作用。     

JNK基因RNAi对镉致293细胞凋亡的影响

目的利用RNAi技术探讨JNK基因在镉致293细胞凋亡过程中的作用。方法细胞转染siRNA-JNK后染镉,用rt-PCR、Western blotting法测JNK基因表达,流式细胞术测细胞凋亡,四甲基偶氮唑盐(MTT)法测细胞活力。结果30μmol/L氯化镉可使293细胞JNK基因mRNA和蛋白表达明显增高,细胞凋亡增加。siRNA-JNK可抑制这些效应,而错义siRNA-JNK和单纯转染试剂无效。结论JNK基因在镉致293细胞凋亡过程中起到关键作用。     

JNK/MAPK途径调控机制研究进展

JNK信号途径与多种疾病的发病机制有关，如癌症、中风、鳞皮病、心脏病、发炎和神经萎缩等疾病。抑制JNK途径的药物具有一定的临床应用价值，因此JNK是一个分子治疗靶。JNK信号途径中的各成员相互作用的机制是目前研究热点之一，本文就此研究的进展作一综述。     

V6421-APP 过度表达的 PC12 细胞凋亡的信号传导机制

目的:研究过度表达人的 V6421-APP 蛋白的 PC12 细胞在氧化应激状态下引起细胞凋亡的信号转导途径.方法:在建立稳定表达人的 APP,V6421-APP 蛋白的细胞株的基础上,使用 MTT、Hoechst33342 观察在无血清培养 24 小时后,100μmol/L H2O2 作用 24 小时对PC12 细胞的影响.使用 Western 检测引起细胞凋亡的过程中可能的相关基因 p-jnk,fasl 的表达.结果:通过 MTT 和 Hoechst33342 分别证实无血清培养 24 小时后氧化应激损伤,V642-IAPP 转染组细胞损伤数目和凋亡数目明显增加.Western 印迹法显示存凋亡过程中,过度表达 V6421-APP 组 p-JNK 和 FasL 的蛋白表达明显增多.结论:在氧化应激引起与阿尔茨海默病相关的过度表达 V642-IAPP 细胞的凋亡过程中,p-TNK,FasL 都参与细胞凋亡的过程.     

Hibiscus anthocyanins rich extract-induced apoptotic cell death in human promyelocytic leukemia cells

Hibiscus sabdariffa Linne (Malvaceae), an attractive plant believed to be native to Africa, is cultivated in the Sudan and Eastern Taiwan. Anthocyanins exist widely in many vegetables and fruits. Some reports demonstrated that anthocyanins extracted from H. sabdariffa L., Hibiscus anthocyanins (HAs) (which are a group of natural pigments existing in the dried calyx of H. sabdariffa L.) exhibited antioxidant activity and liver protection. Therefore, in this study, we explored the effect of HAs on human cancer cells. The result showed that HAs could cause cancer cell apoptosis, especially in HL-60 cells. Using flow cytometry, we found that HAs treatment (0-4 mg/ml) markedly induced apoptosis in HL-60 cells in a dose- and time-dependent manner. The result also revealed increased phosphorylation in p38 and c-Jun, cytochrome c release, and expression of tBid, Fas, and FasL in the HAs-treated HL-60 cells. We further used SB203580 (p38 inhibitor), PD98059 (MEK inhibitor), SP600125 (JNK inhibitor), and wortmannin (phosphatidylinositol 3-kinase; PI-3K inhibitor) to evaluate their effect on the HAs-induced HL-60 death. The data showed that only SB203580 had strong potential in inhibiting HL-60 cell apoptosis and related protein expression and phosphorylation. Therefore, we suggested that HAs mediated HL-60 apoptosis via the p38-FasL and Bid pathway. According to these results, HAs could be developed as chemopreventive agents. However, further investigations into the specificity and mechanism(s) of HAs are needed.     

Insulin inhibits AMPA-induced neuronal damage via stimulation of protein kinase B (Akt)

Summary. We designed a series of experiments to explore the neuroprotective effects of insulin. Insulin significantly inhibited the -amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA)-induced neuronal cell damage as evidenced by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium-bromide (MTT) assay. However, insulin had little affect on the AMPA-induced glial cell damage. To determine whether insulin inhibits AMPA-induced excitotoxicity, we performed grease-gap recording assays using rat brain slices. In these experiments, insulin also significantly inhibited AMPA-induced depolarization. Flow cytometry and DNA fragmentation assays showed that insulin inhibits AMPA-induced apoptosis and DNA fragmentation, respectively. Insulin stimulated protein kinase B (Akt) activity, whereas AMPA pretreatment did not alter the insulin-stimulated Akt activity. On the contrary, insulin blocked induction of SAPK/JNK, which AMPA stimulated. Taken together, these results suggest that insulin exerts neuroprotective effects by inhibiting AMPA-induced excitotoxicity and apoptosis, possibly by activating Akt and blocking SAPK/JNK.     

JNK potentiates TNF-stimulated necrosis by increasing the production of cytotoxic reactive oxygen species

The c-Jun NH(2)-terminal kinase (JNK) has been implicated in both cell death and survival responses to different stimuli. Here we reexamine the function of JNK in tumor necrosis factor (TNF)-stimulated cell death using fibroblasts isolated from wild-type, Mkk4(-/-) Mkk7(-/-), and Jnk1(-/-) Jnk2(-/-) mice. We demonstrate that JNK can act to suppress TNF-stimulated apoptosis. However, we find that JNK can also potentiate TNF-stimulated necrosis by increasing the production of reactive oxygen species (ROS). Together, these data indicate that JNK can shift the balance of TNF-stimulated cell death from apoptosis to necrosis. Increased necrosis may represent a contributing factor in stress-induced inflammatory responses mediated by JNK.     

An essential role of the JIP1 scaffold protein for JNK activation in adipose tissue

The c-Jun NH2-terminal kinase (JNK) is activated during obesity. One consequence of obesity is that JNK phosphorylates the adapter protein insulin receptor substrate 1 (IRS-1) on Ser 307 and inhibits signaling by the insulin receptor. JNK can therefore cause peripheral insulin resistance during obesity and may contribute to the development of type 2 diabetes. Here we report that the JNK-interacting protein 1 (JIP1) scaffold protein, which binds components of the JNK signaling module, is essential for JNK activation in the adipose tissue of obese mice. These data identify JIP1 as a novel molecular target for therapeutic intervention in the development of obesity.