Abstract:
OBJECTIVE To explore the effect of curcumin on phosphatidylinositol-3-kinase/protein kinase B/mammalian target of rapamycin(PI3K/Akt/mTOR) pathway in cell models of Parkinson's disease(PD) and discuss whether it can enhance autophagy by inhibiting this pathway to protect cell models of PD.
METHODS SH-SY5Y human neuroblastoma cell was dealt with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine to build cell models of PD. Control group, model group, curcumin group, curcumin and insulin-like growth factor 1(IGF-1) group, curcumin and LY294002 group were set. Curcumin, curcumin combined with IGF-1 which was PI3K pathway activator and curcumin combined with LY294002 which was PI3K pathway inhibitor were respectively used for intervention treatment. After 24 h of drug treatment, cell morphology was observed under a light microscope, cell counting kit-8 assay was used to detect cell activity, the number of surviving dopamine neurons was detected by immunofluorescence staining with tyrosine hydroxylase, Western blotting was used to detect the protein expression of PI3K, phospho-Akt(p-Akt), phospho-mTOR(p-mTOR), α-synuclein(α-Syn) and microtubule-associated protein 1 light chain 3 beta(LC3B) which was autophagy-related protein.
RESULTS Compared with model group, the state of cell shrinkage and vacuolar degeneration was improved, the cell survival rate was increased(
P<0.05), the survival number of dopaminergic neurons was increased(
P<0.01), LC3B-II/LC3B-I ratio was increased(
P<0.05), the protein expression of α-Syn was decreased(
P<0.01), and the protein expression of p-Akt and p-mTOR was significantly decreased(
P<0.01) in curcumin group. When the PI3K pathway activator IGF-1 was added, the above effects of curcumin were basically offset. When the PI3K pathway inhibitor LY294002 was added, compared with single curcumin intervention, although the LC3B-II/LC3B-I ratio was increased(
P<0.05), the expression of α-Syn protein was increased(
P<0.05), and the survival number of DA neurons was decreased(
P<0.01).
CONCLUSION Curcumin can inhibit the activation of PI3K/Akt/mTOR signaling pathway in cell models of PD, thereby enhance the autophagy function of cells and promote the clearance of α-Syn, which is one of the main mechanisms of its neuroprotective effect.