title: Mitochondrial Apoptotic Pathway Is Activated by H2O2-Mediated Oxidative Stress in BmN-SWU1 Cells from Bombyx mori Ovary.
abstract: Apoptosis is a known regulator of morphogenetic events. In mammals, the critical role of oxidative stress-induced apoptosis has been well-studied; however, in insects the role of oxidative stress in apoptosis is not clear. In a previous study, we showed that apoptosis-related genes are present in the silkworm Bombyx mori, an important lepidopteran insect model. In this study, we evaluated the effect of H2O2-induced oxidative stress on apoptosis, reactive oxygen species (ROS) levels, mitochondrial response, cytochrome c release and apoptosis-related gene expression in the BmN-SWU1 cell line from B. mori ovaries. Our results showed that BmN-SWU1 cells exposed to H2O2 showed cell protuberances, cytoplasmic condensation, apoptotic bodies, DNA ladder formation and caspase activities indicating apoptosis. H2O2-induced apoptosis also increased intracellular ROS level, changed mitochondrial distribution, reduced mitochondrial membrane potential and increased the release of cytochrome c from mitochondria. Furthermore, western blot analysis revealed a significant increase in p53 and cytochrome c expression, and a decrease in Bcl-2 expression compared to the controls. Moreover, quantitative real-time PCR (qRT-PCR) showed an increase in the transcript levels of BmICE, Bmapaf-1 and BmEndoG by 439.5%, 423.9% and 42.2%, respectively, after treatment with 1 μM H2O2 for 24 h. However, the transcript levels of Bmbuffy declined by 41.4% after 24 h of exposure to 1 μM H2O2. These results show that H2O2 treatment induced apoptosis in BmN-SWU1 cells via the mitochondrial apoptotic pathway. Further, it appears that oxidative stress induced by H2O2 activates both caspase-dependent and caspase-independent mitochondrial apoptotic pathways in silkworm cells. Taken together, these findings improve our knowledge of apoptosis in silkworm and the apoptotic pathways in insects.
authors.affiliation: State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, 400716, China; Key Laboratory for Sericulture Functional Genomics and Biotechnology of Agricultural Ministry, Southwest University, Chongqing, 400716, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, 400716, China.
authors.forename: Yan-Fen
authors.initials: YF
authors.lastname: Hu
authors.affiliation: State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, 400716, China.
authors.forename: La
authors.initials: L
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, 400716, China.
authors.forename: Wen-Fu
authors.initials: WF
authors.lastname: Xiao
authors.affiliation: State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, 400716, China.
authors.forename: Xi-Yan
authors.initials: XY
authors.lastname: Bao
authors.affiliation: State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, 400716, China.
authors.forename: Chun
authors.initials: C
authors.lastname: Pan
authors.affiliation: State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, 400716, China.
authors.forename: Hua-Shan
authors.initials: HS
authors.lastname: Yi
authors.affiliation: State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, 400716, China.
authors.forename: Xiang-Yun
authors.initials: XY
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, 400716, China; Key Laboratory for Sericulture Functional Genomics and Biotechnology of Agricultural Ministry, Southwest University, Chongqing, 400716, China.
authors.forename: Min-Hui
authors.initials: MH
authors.lastname: Pan
authors.affiliation: State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, 400716, China; Key Laboratory for Sericulture Functional Genomics and Biotechnology of Agricultural Ministry, Southwest University, Chongqing, 400716, China.
authors.forename: Cheng
authors.initials: C
authors.lastname: Lu
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D012831:Bombyx / Q000378:metabolism*; D002460:Cell Line; D045304:Cytochromes c / Q000378:metabolism; D005260:Female; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D010053:Ovary / Q000378:metabolism* / Q000473:pathology; D018384:Oxidative Stress / Q000187:drug effects*; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: D017382:Reactive Oxygen Species; D045304:Cytochromes c; D006861:Hydrogen Peroxide