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Mitochondrial Apoptotic Pathway Is Activated by H2O2-Mediated Oxidative Stress in BmN-SWU1 Cells from Bombyx mori Ovary.

Chen P, Hu YF, Wang L, Xiao WF, Bao XY, Pan C, Yi HS, Chen XY, Pan MH, Lu C - PLoS ONE (2015)

Bottom Line: H2O2-induced apoptosis also increased intracellular ROS level, changed mitochondrial distribution, reduced mitochondrial membrane potential and increased the release of cytochrome c from mitochondria.These results show that H2O2 treatment induced apoptosis in BmN-SWU1 cells via the mitochondrial apoptotic pathway.Taken together, these findings improve our knowledge of apoptosis in silkworm and the apoptotic pathways in insects.

View Article: PubMed Central - PubMed

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.

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.

No MeSH data available.


Related in: MedlinePlus

Effects of H2O2 on the intracellular ROS, membrane potential and mitochondrial distribution in BmN-SWU1 cells.(A) Accumulation of intracellular ROS in BmN-SWU1 cells after treatment with H2O2. All treated groups were compared with the control (0 h). Values are mean ± SD (n = 3). **, P < 0.01, Student’s t-test. (B) Effects of H2O2 exposure on the mitochondrial membrane potential (ΔΨm) in BmN-SWU1 cells. (C) Changes in mitochondrial distribution after H2O2 treatment. Scale bars = 5 μm.
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pone.0134694.g002: Effects of H2O2 on the intracellular ROS, membrane potential and mitochondrial distribution in BmN-SWU1 cells.(A) Accumulation of intracellular ROS in BmN-SWU1 cells after treatment with H2O2. All treated groups were compared with the control (0 h). Values are mean ± SD (n = 3). **, P < 0.01, Student’s t-test. (B) Effects of H2O2 exposure on the mitochondrial membrane potential (ΔΨm) in BmN-SWU1 cells. (C) Changes in mitochondrial distribution after H2O2 treatment. Scale bars = 5 μm.

Mentions: H2O2 is a major component of ROS and has a strong ability for oxidation. In the present study, the level of ROS in H2O2 treated BmN-SWU1 cells was investigated by labelling with a DCFH-DA fluorescent probe. Our results showed that the DCF intensity gradually increased with treatment time reaching a maximum at 24 h suggesting that exposure of BmN-SWU1 cells to H2O2 resulted in a time-dependent increase in ROS levels (Fig 2A).


Mitochondrial Apoptotic Pathway Is Activated by H2O2-Mediated Oxidative Stress in BmN-SWU1 Cells from Bombyx mori Ovary.

Chen P, Hu YF, Wang L, Xiao WF, Bao XY, Pan C, Yi HS, Chen XY, Pan MH, Lu C - PLoS ONE (2015)

Effects of H2O2 on the intracellular ROS, membrane potential and mitochondrial distribution in BmN-SWU1 cells.(A) Accumulation of intracellular ROS in BmN-SWU1 cells after treatment with H2O2. All treated groups were compared with the control (0 h). Values are mean ± SD (n = 3). **, P < 0.01, Student’s t-test. (B) Effects of H2O2 exposure on the mitochondrial membrane potential (ΔΨm) in BmN-SWU1 cells. (C) Changes in mitochondrial distribution after H2O2 treatment. Scale bars = 5 μm.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4520666&req=5

pone.0134694.g002: Effects of H2O2 on the intracellular ROS, membrane potential and mitochondrial distribution in BmN-SWU1 cells.(A) Accumulation of intracellular ROS in BmN-SWU1 cells after treatment with H2O2. All treated groups were compared with the control (0 h). Values are mean ± SD (n = 3). **, P < 0.01, Student’s t-test. (B) Effects of H2O2 exposure on the mitochondrial membrane potential (ΔΨm) in BmN-SWU1 cells. (C) Changes in mitochondrial distribution after H2O2 treatment. Scale bars = 5 μm.
Mentions: H2O2 is a major component of ROS and has a strong ability for oxidation. In the present study, the level of ROS in H2O2 treated BmN-SWU1 cells was investigated by labelling with a DCFH-DA fluorescent probe. Our results showed that the DCF intensity gradually increased with treatment time reaching a maximum at 24 h suggesting that exposure of BmN-SWU1 cells to H2O2 resulted in a time-dependent increase in ROS levels (Fig 2A).

Bottom Line: H2O2-induced apoptosis also increased intracellular ROS level, changed mitochondrial distribution, reduced mitochondrial membrane potential and increased the release of cytochrome c from mitochondria.These results show that H2O2 treatment induced apoptosis in BmN-SWU1 cells via the mitochondrial apoptotic pathway.Taken together, these findings improve our knowledge of apoptosis in silkworm and the apoptotic pathways in insects.

View Article: PubMed Central - PubMed

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.

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.

No MeSH data available.


Related in: MedlinePlus