Wang Zheng, Cheng Xingan, Meng Qianqian, Wang Peidan, Shu Benshui, Hu Qiongbo, Hu Meiying, Zhong Guohua
Key Laboratory of Natural Pesticide and Chemical Biology, Ministry of Education, and Lab of Insect Toxicology, South China Agricultural University, No. 483, Wushan, Tianhe, Guangzhou 510642, People's Republic of China.
Key Laboratory of Natural Pesticide and Chemical Biology, Ministry of Education, and Lab of Insect Toxicology, South China Agricultural University, No. 483, Wushan, Tianhe, Guangzhou 510642, People's Republic of China; Institute of Natural Product Chemistry, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, People's Republic of China.
Int J Biochem Cell Biol. 2015 Jul;64:126-35. doi: 10.1016/j.biocel.2015.03.018. Epub 2015 Apr 4.
Azadirachtin as a kind of botanical insecticide has been widely used in pest control. We previously reported that azadirachtin could induce apoptosis of Spodoptera litura cultured cell line Sl-1, which involves in the up-regulation of P53 protein. However, the detailed mechanism of azadirachtin-induced apoptosis is not clearly understood in insect cultured cells. The aim of the present study was to address the involvement of lysosome and lysosomal protease in azadirachtin-induced apoptosis in Sf9 cells. The result confirmed that azadirachtin indeed inhibited proliferation and induced apoptosis. The lysosomes were divided into different types as time-dependent manner, which suggested that changes of lysosomes were necessarily physiological processes in azadirachtin-induced apoptosis in Sf9 cells. Interestingly, we noticed that azadirachtin could trigger lysosomal membrane permeabilization and cathepsin L releasing to cytosol. Z-FF-FMK (a cathepsin L inhibitor), but not CA-074me (a cathepsin B inhibitor), could effectively hinder the apoptosis induced by azadirachtin in Sf9 cells. Meanwhile, the activity of caspase-3 could also be inactivated by the inhibition of cathepsin L enzymatic activity induced by Z-FF-FMK. Taken together, our findings suggest that azadirachtin could induce apoptosis in Sf9 cells in a lysosomal pathway, and cathepsin L plays a pro-apoptosis role in this process through releasing to cytosol and activating caspase-3.
印楝素作为一种植物源杀虫剂已被广泛应用于害虫防治。我们之前报道过印楝素可诱导斜纹夜蛾培养细胞系Sl-1凋亡，这涉及P53蛋白的上调。然而，在昆虫培养细胞中印楝素诱导凋亡的详细机制尚不清楚。本研究的目的是探讨溶酶体和溶酶体蛋白酶在印楝素诱导的Sf9细胞凋亡中的作用。结果证实印楝素确实抑制增殖并诱导凋亡。溶酶体随时间呈不同类型变化，这表明溶酶体的变化是印楝素诱导Sf9细胞凋亡过程中必然的生理过程。有趣的是，我们注意到印楝素可引发溶酶体膜通透性增加以及组织蛋白酶L释放到细胞质中。Z-FF-FMK（一种组织蛋白酶L抑制剂）而非CA-074me（一种组织蛋白酶B抑制剂）可有效阻碍印楝素诱导的Sf9细胞凋亡。同时，Z-FF-FMK诱导的组织蛋白酶L酶活性抑制也可使caspase-3的活性失活。综上所述，我们的研究结果表明印楝素可通过溶酶体途径诱导Sf9细胞凋亡，并且组织蛋白酶L在该过程中通过释放到细胞质中并激活caspase-3发挥促凋亡作用。
