Neuroprotection by sodium ferulate against glutamate-induced apoptosis is mediated by ERK and PI3 kinase pathways.
OBJECTIVE
To investigate whether sodium ferulate (SF) can protect cortical neurons from glutamate-induced neurotoxicity and the mechanisms responsible for this protection.


METHODS
Cultured cortical neurons were incubated with 50 micromol/L glutamate for either 30 min or 24 h, with or without pre-incubation with SF (100, 200, and 500 micromol/L, respectively). LY294002, wortmannin, PD98059, and U0126 were added respectively to the cells 1 h prior to SF treatment. After incubation with glutamate for 24 h, neuronal apoptosis was quantified by scoring the percentage of cells with apoptotic nuclear morphology after Hoechst 33258 staining. After incubation with glutamate for either 30 min or 24 h, cellular extracts were prepared for Western blotting of active caspase-3, poly (ADP-ribose) polymerase (PARP), mu-calpain, Bcl-2, phospho-Akt, phosphorylated ribosomal protein S6 protein kinase (p70S6K), phospho-mitogen-activated protein kinase kinase (MEK1/2) and phosphorylated extracellular signal-regulated kinase (ERK) 1/2.


RESULTS
SF reduced glutamate-evoked apoptotic morphology, active caspase-3 protein expression, and PARP cleavage and inhibited the glutamate-induced upregulation of the mu-calpain protein level. The inhibition of the phosphatidylinositol 3-kinase (PI3K) and the MEK/ERK1/2 pathways partly abrogated the protective effect of SF against glutamate-induced neuronal apoptosis. SF prevented the glutamate-induced decrease in the activity of the PI3K/Akt/p70S6K and the MEK/ERK1/2 pathways. Moreover, incubation of cortical neurons with SF for 30 min inhibited the reduction of the Bcl-2 expression induced by glutamate.


CONCLUSIONS
The results indicate that PI3K/Akt/p70S6K and the MEK/ERK signaling pathways play important roles in the protective effect of SF against glutamate toxicity in cortical neurons.
Jin
Ying
Y
Department of Pharmacology, Liaoning Medical University, Jinzhou 121001, China. jyjinying@yahoo.com.cn
Yan
En-zhi
EZ
Fan
Ying
Y
Guo
Xiao-li
XL
Zhao
Yan-jie
YJ
Zong
Zhi-hong
ZH
Liu
Zhuo
Z
D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D002478:Cells, Cultured; D003373:Coumaric Acids / Q000494:pharmacology*; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism*; D018698:Glutamic Acid / Q000494:pharmacology*; D018696:Neuroprotective Agents / Q000494:pharmacology*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley
D003373:Coumaric Acids; D018696:Neuroprotective Agents; D018698:Glutamic Acid; C004999:ferulic acid; D019869:Phosphatidylinositol 3-Kinases; D048049:Extracellular Signal-Regulated MAP Kinases