Phosphatidylinositol-3 kinase/Akt and GSK-3 mediated cytoprotective effect of epigallocatechin gallate on oxidative stress-injured neuronal-differentiated N18D3 cells.
Epigallocatechin gallate (EGCG) is one of most famous compounds of green tea. EGCG suppresses apoptosis induced by oxidative radical stress through several mechanisms. This study was designed to investigate whether EGCG plays a cytoprotective role by activating phosphatidylinositol-3 kinase (PI3K)/Akt-dependent anti-apoptotic pathway and inhibiting glycogen synthase kinase-3 (GSK-3) activity in oxidative stressed N18D3 neural cells. N18D3 cells, mouse neuroblastoma X dorsal root ganglion hybrid cell line, were pre-treated with EGCG or z-VAD-fmk, non-selective caspase inhibitor used as a control substance, for 2 h. The N18D3 cells were then exposed to low concentration of H(2)O(2) (100 microM) for 30 min, and further incubated for 24 h. MTT (3,[4,5-dimethylthiazol]-2-yl) assay and trypan blue staining were used to identify cell viability. Immunoreactivity (IR) of PI3K, Akt, and GSK-3 beta were measured by Western blotting. MTT assay and trypan blue staining showed that EGCG and z-VAD-fmk significantly increased cell viability, and IR of PI3K, phospho-Akt and phospho-GSK-3 beta was significantly increased in the cells treated with EGCG, but not in z-VAD-fmk treated. These results imply that EGCG has neuroprotective effect by increasing PI3K/Akt-dependent anti-apoptotic signals.
Koh
Seong-Ho
SH
Department of Neurology, College of Medicine, Hanyang University, Seongdong-gu, Seoul 133-791, South Korea.
Kim
Seung H
SH
Kwon
Hyugsung
H
Kim
Jun Gyou
JG
Kim
Ju Hwan
JH
Yang
Ki-Hwa
KH
Kim
Juhan
J
Kim
Seung U
SU
Yu
Hyun-Jeung
HJ
Do
Byung Rok
BR
Kim
Kyung Suk
KS
Jung
Hai Kwan
HK
D000590:Amino Acid Chloromethyl Ketones / Q000494:pharmacology; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D015153:Blotting, Western; D061945:Caspase Inhibitors; D002392:Catechin / Q000031:analogs & derivatives* / Q000494:pharmacology*; D002454:Cell Differentiation / Q000187:drug effects; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D038362:Glycogen Synthase Kinase 3 / Q000502:physiology*; D006861:Hydrogen Peroxide / Q000494:pharmacology; D051379:Mice; D008807:Mice, Inbred BALB C; D009474:Neurons / Q000187:drug effects / Q000502:physiology* / Q000648:ultrastructure; D018696:Neuroprotective Agents / Q000494:pharmacology*; D051058:Oncogene Protein v-akt; D016877:Oxidants / Q000494:pharmacology; D018384:Oxidative Stress / Q000187:drug effects / Q000502:physiology*; D019869:Phosphatidylinositol 3-Kinases / Q000502:physiology*; D015682:Retroviridae Proteins, Oncogenic / Q000502:physiology*; D015398:Signal Transduction / Q000187:drug effects
D000590:Amino Acid Chloromethyl Ketones; D061945:Caspase Inhibitors; D004791:Enzyme Inhibitors; D018696:Neuroprotective Agents; D016877:Oxidants; D015682:Retroviridae Proteins, Oncogenic; C096713:benzyloxycarbonylvalyl-alanyl-aspartyl fluoromethyl ketone; D002392:Catechin; D006861:Hydrogen Peroxide; C045651:epigallocatechin gallate; D019869:Phosphatidylinositol 3-Kinases; D051058:Oncogene Protein v-akt; D038362:Glycogen Synthase Kinase 3