Role of PI3-K/Akt pathway and its effect on glial cell line-derived neurotrophic factor in midbrain dopamine cells
Abstract
Aim: 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 THir
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). Conclusion:
The PI3-K/Akt pathway mediates the survival/differentiation effect of GDNF on
DA cells.
Keywords:
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 THir
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). Conclusion:
The PI3-K/Akt pathway mediates the survival/differentiation effect of GDNF on
DA cells.