Mechanisms of Panax ginseng in preventing rat pheochromocytoma cells from apoptosis.
OBJECTIVE
Although ginseng root possesses dominant central therapeutic effects and has recently undergone investigations for treating different neuronal diseases, most of its mechanisms are still unknown. Therefore, the neuroprotective mechanisms of ginseng were studied.


METHODS
The protection afforded by different methanol extracts of Panax ginseng (PG) was tested in a serum deprivation-induced apoptotic model using neuronal-like pheochromocytoma (PC12) cells. An MTT assay, annexin V-FITC staining, and Western blots were, respectively, applied to identify the viability of cells, the apoptotic form of cell death, and the activity of antiapoptotic signaling.


RESULTS
The known antiapoptotic PI3-K/Akt and MEK/ERK pathways in this system were ruled out due to failure of LY 294002 and PD 98059 to block the protection by PG. A protein kinase A (PKA) inhibitor was found to block the protection by PG and PG-induced CREB phosphorylation, suggesting that the PKA/CREB pathway mediates the protective effect of PG. Downregulation of classical and novel PKCs failed to block the protection by PG, while an atypical PKC inhibitor blocked protection by PG.


CONCLUSIONS
PKA and atypical PKC are important for the protection afforded by PG in preventing serum deprivation-induced PC12 cell apoptosis.
Lin
Yun-Lian
YL
National Research Institute of Chinese Medicine, Taipei, Taiwan.
Huang
Chuen-Lin
CL
Lee
Yi-Chao
YC
Liao
Wei-Chen
WC
Lai
Wen-Lin
WL
Lin
Yen-Ju
YJ
Huang
Nai-Kuei
NK
D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western; D016716:PC12 Cells; D005894:Panax / Q000737:chemistry*; D010673:Pheochromocytoma / Q000473:pathology*; D010936:Plant Extracts / Q000494:pharmacology*; D011494:Protein Kinases / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D051381:Rats
D010936:Plant Extracts; D011494:Protein Kinases; D051057:Proto-Oncogene Proteins c-akt