Zn2+-induced ERK activation mediated by reactive oxygen species causes cell death in differentiated PC12 cells.
Recent studies have provided evidence that Zn2+ plays a crucial role in ischemia- and seizure-induced neuronal death. However, the intracellular signaling pathways involved in Zn2+-induced cell death are largely unknown. In the present study, we investigated the roles of mitogen-activated protein kinases (MAPKs), such as c-Jun N-terminal kinase (JNK), p38 MAPK and extracellular signal-regulated kinase (ERK), and of reactive oxygen species (ROS) in Zn2+-induced cell death using differentiated PC12 cells. Intracellular accumulation of Zn2+ induced by the combined application of pyrithione (5 microM), a Zn2+ ionophore, and Zn2+ (10 microM) caused cell death and activated JNK and ERK, but not p38 MAPK. Preventing JNK activation by the expression of dominant negative SEK1 (SEKAL) did not attenuate Zn2+-induced cell death, whereas the inhibition of ERK with PD98059 and the expression of dominant negative Ras mutant (RasN17) significantly prevented cell death. Inhibition of protein kinase C (PKC) and phosphatidylinositol-3 kinase had little effect on Zn2+-induced ERK activation. Intracellular Zn2+ accumulation resulted in the generation of ROS, and antioxidants prevented both the ERK activation and the cell death induced by Zn2+. Therefore, we conclude that although Zn2+ activates JNK and ERK, only ERK contributes to Zn2+-induced cell death, and that ERK activation is mediated by ROS via the Ras/Raf/MEK/ERK signaling pathway.
Seo
S R
SR
Department of Oral Biology and Oral Science Research Center, College of Dentistry, Yonsei University, Seoul, Korea.
Chong
S A
SA
Lee
S I
SI
Sung
J Y
JY
Ahn
Y S
YS
Chung
K C
KC
Seo
J T
JT
D000818:Animals; D000935:Antifungal Agents / Q000494:pharmacology; D000975:Antioxidants / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects*; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005419:Flavonoids / Q000494:pharmacology; D015151:Immunoblotting; D007211:Indoles / Q000494:pharmacology; D048031:JNK Mitogen-Activated Protein Kinases; D020935:MAP Kinase Signaling System / Q000502:physiology; D008301:Maleimides / Q000494:pharmacology; D008856:Microscopy, Fluorescence; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D009474:Neurons / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D016716:PC12 Cells; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism; D011725:Pyridines / Q000494:pharmacology; D051381:Rats; D017382:Reactive Oxygen Species / Q000378:metabolism*; D013871:Thiones; D013997:Time Factors; D014162:Transfection; D015032:Zinc / Q000494:pharmacology*; D048051:p38 Mitogen-Activated Protein Kinases; D018631:ras Proteins / Q000378:metabolism
D000935:Antifungal Agents; D000975:Antioxidants; D004791:Enzyme Inhibitors; D005419:Flavonoids; D007211:Indoles; D048031:JNK Mitogen-Activated Protein Kinases; D008301:Maleimides; D020928:Mitogen-Activated Protein Kinases; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011493:Protein Kinase C; D011725:Pyridines; D017382:Reactive Oxygen Species; D013871:Thiones; D015032:Zinc; D048051:p38 Mitogen-Activated Protein Kinases; D018631:ras Proteins; C008704:pyrithione; C070515:bisindolylmaleimide I; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one