Role of PI3-K/Akt pathway and its effect on glial cell line-derived neurotrophic factor in midbrain dopamine cells.
OBJECTIVE
To explore the intracellular mechanisms underlying the survival/differentiation effect of the glial cell line-derived neurotrophic factor (GDNF) on dopamine (DA) cells.


METHODS
Midbrain slice culture and primary cell culture were established, and the cultures were divided into 3 groups: control group, GDNF group, and the phosphatidylinositol 3-kinase/Akt (PI3-K/Akt) pathway-inhibited group. Then the expression of tyrosine hydroxylase (TH) was detected by immunostaining as well as Western blotting.


RESULTS
GDNF treatment induced an increase in the number of TH-immunoreactive (ir) cells and the neurite number of TH-ir cells, as well as in the level of TH expression in cultures (Number of TH-ir cells in the slice culture: control group, 8.76+/-0.75; GDNF group, 18.63+/-0.95. Number of TH-ir cells and neurite number of TH-ir cells in cell culture: control group, 3.65+/-0.88 and 2.49+/-0.42; GDNF group, 6.01+/-0.43 and 4.89+/-0.46). Meanwhile, the stimulation of cultured cells with GDNF increased the phosphorylation of Akt, which is a downstream effector of PI3-K/Akt. The effects of GDNF were specifically blocked by the inhibitor of the PI3-K/Akt pathway, wortmannin (Number of TH-ir cells in slice culture: PI3-K/Akt pathway-inhibited group, 6.98+/-0.58. Number of TH-ir cells and neurite number of TH-ir cells in cell culture: PI3-K/Akt pathway-inhibited group, 3.79+/-0.62 and 2.50+/-0.25, respectively).


CONCLUSIONS
The PI3-K/Akt pathway mediates the survival/differentiation effect of GDNF on DA cells.
Wang
Hong-jun
HJ
Research Centre of Neurobiology, Xuzhou Medical College, Xuzhou 221002, China.
Cao
Jun-ping
JP
Yu
Jing-kao
JK
Gao
Dian-shuai
DS
D000818:Animals; D002454:Cell Differentiation / Q000187:drug effects; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D004298:Dopamine / Q000502:physiology*; D048049:Extracellular Signal-Regulated MAP Kinases / Q000502:physiology; D005260:Female; D051100:Glial Cell Line-Derived Neurotrophic Factor / Q000494:pharmacology*; D020935:MAP Kinase Signaling System; D008636:Mesencephalon / Q000166:cytology / Q000187:drug effects*; D019869:Phosphatidylinositol 3-Kinases / Q000502:physiology*; D011247:Pregnancy; D051057:Proto-Oncogene Proteins c-akt / Q000502:physiology*; D051381:Rats; D015398:Signal Transduction / Q000502:physiology*
D051100:Glial Cell Line-Derived Neurotrophic Factor; D019869:Phosphatidylinositol 3-Kinases; D051057:Proto-Oncogene Proteins c-akt; D048049:Extracellular Signal-Regulated MAP Kinases; D004298:Dopamine