Hsuuw Yan-Der, Kuo Tzong-Fu, Lee Kun-Hsiung, Liu Yen-Chih, Huang Yu-Ting, Lai Ching-Yu, Chan Wen-Hsiung
Department of Life Science, National Pingtung University of Science and Technology, Pingtung, Taiwan.
Ann N Y Acad Sci. 2009 Aug;1171:501-8. doi: 10.1111/j.1749-6632.2009.04691.x.
Ginkgolide B (GKB), the major active component of Ginkgo biloba extracts, can both stimulate and inhibit apoptotic signaling. We previously showed that ginkgolide treatment of mouse blastocysts induces apoptosis, decreases cell numbers, retards the proliferation and development of mouse embryonic stem cells and blastocysts in vitro, and causes developmental injury in vivo. However, the precise molecular mechanisms underlying its actions are currently unknown. Here, our study further revealed that GKB induced apoptotic biochemical changes, including activation of JNK, caspase-3, and p21-activated protein kinase 2 (PAK2), in ESC-B5 mouse embryonic stem cells. Treatment of ESC-B5 cells with a JNK-specific inhibitor (SP600125) reduced GKB-induced activation of both JNK and caspase-3, indicating that JNK activity is required for GKB-induced caspase activation. Experiments using caspase-3 inhibitors and antisense oligonucleotides against PAK2 showed that caspase-3 activation is required for PAK2 activation and both of these activations are required for GKB-induced apoptosis in ESC-B5 cells.
银杏内酯B（GKB）是银杏叶提取物的主要活性成分，既能刺激又能抑制凋亡信号传导。我们之前表明，用银杏内酯处理小鼠囊胚可诱导凋亡、减少细胞数量、在体外延缓小鼠胚胎干细胞和囊胚的增殖与发育，并在体内造成发育损伤。然而，其作用背后的确切分子机制目前尚不清楚。在此，我们的研究进一步揭示，GKB在ESC - B5小鼠胚胎干细胞中诱导凋亡生化变化，包括JNK、caspase - 3和p21激活蛋白激酶2（PAK2）的激活。用JNK特异性抑制剂（SP600125）处理ESC - B5细胞可降低GKB诱导的JNK和caspase - 3激活，表明JNK活性是GKB诱导caspase激活所必需的。使用caspase - 3抑制剂和针对PAK2的反义寡核苷酸进行的实验表明，caspase - 3激活是PAK2激活所必需的，且这两种激活都是GKB诱导ESC - B5细胞凋亡所必需的。
