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Paraquat Induces Apoptosis through Cytochrome C Release and ERK Activation.

Seo HJ, Choi SJ, Lee JH - Biomol Ther (Seoul) (2014)

Bottom Line: Paraquat treatment resulted in activation of ERK, and U0126, inhibitors of the MEK/ERK signaling pathway, prevented apoptosis.Moreover, paraquat-induced apoptosis was associated with cytochrome C release, which could be prevented by treatment with the MEK inhibitors.Taken together, our findings suggest that ERK activation plays an active role in mediating paraquat-induced apoptosis of NIH3T3 cells.

View Article: PubMed Central - PubMed

Affiliation: Department of Thoracic and Cardiovascular Surgery, Chosun University School of Medicine, Gwangju 501-759, Republic of Korea.

ABSTRACT
Paraquat has been suggested to induce apoptosis by generation of reactive oxygen species (ROS). However, little is known about the mechanism of paraquat-induced apoptosis. Here, we demonstrate that extracellular signal-regulated protein kinase (ERK) is required for paraquat-induced apoptosis in NIH3T3 cells. Paraquat treatment resulted in activation of ERK, and U0126, inhibitors of the MEK/ERK signaling pathway, prevented apoptosis. Moreover, paraquat-induced apoptosis was associated with cytochrome C release, which could be prevented by treatment with the MEK inhibitors. Taken together, our findings suggest that ERK activation plays an active role in mediating paraquat-induced apoptosis of NIH3T3 cells.

No MeSH data available.


The effect of paraquat on activation of JNK and p38 MAPKs. NIH3T3 cells were cotransfected with either Gal4-CHOP trans-reporting system (A) or GAL4-c-Jun trans-reporting system (B) and pRL-Luc, and then cells were treated with different dose of paraquat for 12 h. The luciferase activity was measured as described in Fig. 2A. Results are shown as means ± S.D. (n=3). *<0.05. (C) Cells were preincubated with p38 inhibitors SB203580, or transiently transfected with a combination of JNK1 and JNK2 antisense oligonucleotides (AS) or control oligonuleotide (C), and subsequently treated with 1 mM paraquat for 24 h, and then the extent of apoptosis was measured.
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f4-bt-22-503: The effect of paraquat on activation of JNK and p38 MAPKs. NIH3T3 cells were cotransfected with either Gal4-CHOP trans-reporting system (A) or GAL4-c-Jun trans-reporting system (B) and pRL-Luc, and then cells were treated with different dose of paraquat for 12 h. The luciferase activity was measured as described in Fig. 2A. Results are shown as means ± S.D. (n=3). *<0.05. (C) Cells were preincubated with p38 inhibitors SB203580, or transiently transfected with a combination of JNK1 and JNK2 antisense oligonucleotides (AS) or control oligonuleotide (C), and subsequently treated with 1 mM paraquat for 24 h, and then the extent of apoptosis was measured.

Mentions: JNK (c-Jun N-terminal kinase) and p38 have been implicated in stress-related responses and the induction of apoptosis. Therefore, we investigated whether JNK and p38 involved in the induction of paraquat-induce apoptosis. To compare the patterns of activation of the JNK and p38 pathways in response to paraquat in NIH3T3 cells, cells were cotransfected with either Gal4-c-Jun-firefly luciferase vector for measuring JNK activation, or Gal4-CHOP-firefly luciferase vector for measuring p38 kinase activation and pRL-Luc following exposure to different dose of paraquat for 12 h, and then cells were harvested and luciferase activities were measured. The results, shown in Fig. 4A, B, demonstrated that both p38 and JNK were activated in response to paraquat treatment. To investigate the functional consequences of p38 and JNK activation, paraquat-induced apoptosis after prevention of JNK and p38 was measured. NIH3T3 cells were pretreated with p38 specific inhibitor, SB203580 or transiently transfected with 0.2 μM each antisense JNK1 and JNK2 oligonucleotides (JNK1+JNK2AS), which was phosphorothioate oligonucleotides targeted to JNK1 and JNK2 mRNA to block JNK/SPAK pathway. As shown in Fig. 4C, the JNK1+JNK2AS-transfecting NIH3T3 cells and the treatment of cells with SB203580 during exposure to paraquat did not prevent paraquat-induced apoptosis. These results indicate that although JNK and p38 were activated in response to paraquat, neither JNK nor p38 plays a role in regulating paraquat-induced apoptosis of NIH cells. Taken together, among of the three MAPKs, only ERK appears to play a major role in influencing the survival of paraquat-treated NIH3T3 cells.


Paraquat Induces Apoptosis through Cytochrome C Release and ERK Activation.

Seo HJ, Choi SJ, Lee JH - Biomol Ther (Seoul) (2014)

The effect of paraquat on activation of JNK and p38 MAPKs. NIH3T3 cells were cotransfected with either Gal4-CHOP trans-reporting system (A) or GAL4-c-Jun trans-reporting system (B) and pRL-Luc, and then cells were treated with different dose of paraquat for 12 h. The luciferase activity was measured as described in Fig. 2A. Results are shown as means ± S.D. (n=3). *<0.05. (C) Cells were preincubated with p38 inhibitors SB203580, or transiently transfected with a combination of JNK1 and JNK2 antisense oligonucleotides (AS) or control oligonuleotide (C), and subsequently treated with 1 mM paraquat for 24 h, and then the extent of apoptosis was measured.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4256029&req=5

f4-bt-22-503: The effect of paraquat on activation of JNK and p38 MAPKs. NIH3T3 cells were cotransfected with either Gal4-CHOP trans-reporting system (A) or GAL4-c-Jun trans-reporting system (B) and pRL-Luc, and then cells were treated with different dose of paraquat for 12 h. The luciferase activity was measured as described in Fig. 2A. Results are shown as means ± S.D. (n=3). *<0.05. (C) Cells were preincubated with p38 inhibitors SB203580, or transiently transfected with a combination of JNK1 and JNK2 antisense oligonucleotides (AS) or control oligonuleotide (C), and subsequently treated with 1 mM paraquat for 24 h, and then the extent of apoptosis was measured.
Mentions: JNK (c-Jun N-terminal kinase) and p38 have been implicated in stress-related responses and the induction of apoptosis. Therefore, we investigated whether JNK and p38 involved in the induction of paraquat-induce apoptosis. To compare the patterns of activation of the JNK and p38 pathways in response to paraquat in NIH3T3 cells, cells were cotransfected with either Gal4-c-Jun-firefly luciferase vector for measuring JNK activation, or Gal4-CHOP-firefly luciferase vector for measuring p38 kinase activation and pRL-Luc following exposure to different dose of paraquat for 12 h, and then cells were harvested and luciferase activities were measured. The results, shown in Fig. 4A, B, demonstrated that both p38 and JNK were activated in response to paraquat treatment. To investigate the functional consequences of p38 and JNK activation, paraquat-induced apoptosis after prevention of JNK and p38 was measured. NIH3T3 cells were pretreated with p38 specific inhibitor, SB203580 or transiently transfected with 0.2 μM each antisense JNK1 and JNK2 oligonucleotides (JNK1+JNK2AS), which was phosphorothioate oligonucleotides targeted to JNK1 and JNK2 mRNA to block JNK/SPAK pathway. As shown in Fig. 4C, the JNK1+JNK2AS-transfecting NIH3T3 cells and the treatment of cells with SB203580 during exposure to paraquat did not prevent paraquat-induced apoptosis. These results indicate that although JNK and p38 were activated in response to paraquat, neither JNK nor p38 plays a role in regulating paraquat-induced apoptosis of NIH cells. Taken together, among of the three MAPKs, only ERK appears to play a major role in influencing the survival of paraquat-treated NIH3T3 cells.

Bottom Line: Paraquat treatment resulted in activation of ERK, and U0126, inhibitors of the MEK/ERK signaling pathway, prevented apoptosis.Moreover, paraquat-induced apoptosis was associated with cytochrome C release, which could be prevented by treatment with the MEK inhibitors.Taken together, our findings suggest that ERK activation plays an active role in mediating paraquat-induced apoptosis of NIH3T3 cells.

View Article: PubMed Central - PubMed

Affiliation: Department of Thoracic and Cardiovascular Surgery, Chosun University School of Medicine, Gwangju 501-759, Republic of Korea.

ABSTRACT
Paraquat has been suggested to induce apoptosis by generation of reactive oxygen species (ROS). However, little is known about the mechanism of paraquat-induced apoptosis. Here, we demonstrate that extracellular signal-regulated protein kinase (ERK) is required for paraquat-induced apoptosis in NIH3T3 cells. Paraquat treatment resulted in activation of ERK, and U0126, inhibitors of the MEK/ERK signaling pathway, prevented apoptosis. Moreover, paraquat-induced apoptosis was associated with cytochrome C release, which could be prevented by treatment with the MEK inhibitors. Taken together, our findings suggest that ERK activation plays an active role in mediating paraquat-induced apoptosis of NIH3T3 cells.

No MeSH data available.