DA-9801 Promotes Neurite Outgrowth via ERK1/2-CREB Pathway in PC12 Cells

• Published in: Biological & pharmaceutical bulletin 2015/02/01, Vol.38(2), pp.169-178
• Main Authors: Won, Jong Hoon, Ahn, Kyong Hoon, Back, Moon Jung, Ha, Hae Chan, Jang, Ji Min, Kim, Ha Hyung, Choi, Sang-Zin, Son, Miwon, Kim, Dae Kyong
• Format: Article
• Language: English
• Subjects: Animals; cAMP response element-binding protein (CREB); Cell Survival - drug effects; Cyclic AMP Response Element-Binding Protein - metabolism; DA-9801; diabetic peripheral neuropathy; Dioscorea; extracellular signal-regulated kinase 1/2; MAP Kinase Kinase Kinases - metabolism; MAP Kinase Signaling System - drug effects; neurite outgrowth; Neurites - drug effects; Neurofilament Proteins - metabolism; PC12 Cells; Plant Preparations - pharmacology; Proto-Oncogene Proteins c-raf; Rats
• ISSN: 0918-6158; 1347-5215
• DOI: 10.1248/bpb.b14-00236

In the present study, we examined the mechanisms underlying the effect of DA-9801 on neurite outgrowth. We found that DA-9801 elicits its effects via the mitogen-activated protein kinase (MEK) extracellular signal-regulated kinase (ERK)1/2-cAMP response element-binding protein (CREB) pathway. DA-9801, an extract from a mixture of Dioscorea japonica and Dioscorea nipponica, was reported to promote neurite outgrowth in PC12 cells. The effects of DA-9801 on cell viability and expression of neuronal markers were evaluated in PC12 cells. To investigate DA-9801 action, specific inhibitors targeting the ERK signaling cascade were used. No cytotoxicity was observed in PC12 cells at DA-9801 concentrations of less than 30 µg/mL. In the presence of nerve growth factor (NGF, 2 ng/mL), DA-9801 promoted neurite outgrowth and increased the relative mRNA levels of neurofilament-L (NF-L), a marker of neuronal differentiation. The Raf-1 inhibitor GW5074 and MEK inhibitor PD98059 significantly attenuated DA-9801-induced neurite outgrowth. Additionally, the MEK1 and MEK2 inhibitor SL327 significantly attenuated the increase in the percentage of neurite-bearing PC12 cells induced by DA-9801 treatment. Conversely, the selective p38 mitogen-activated protein kinase inhibitor SB203580 did not attenuate the DA-9801 treatment-induced increase in the percentage of neurite-bearing PC12 cells. DA-9801 enhanced the phosphorylation of ERK1/2 and CREB in PC12 cells incubated with and without NGF. Pretreatment with PD98059 blocked the DA-9801-induced phosphorylation of ERK1/2 and CREB. In conclusion, DA-9801 induces neurite outgrowth by affecting the ERK1/2-CREB signaling pathway. Insights into the mechanism underlying this effect of DA-9801 may suggest novel potential strategies for the treatment of peripheral neuropathy.