Effect and molecular mechanism of mammalian target of rapamycin complex 2 / Akt signaling pathway on 6-hydroxydopamine-treated SH-SY5Y cell model / 解剖学报

ABSTRACT

[Abstract] Objective To study whether the regulation of mammalian target of rapamycin complex 2(mTORC2) / Akt signaling pathway has a protective effect on SH-SY5Y cell line damaged by 6-hydroxydopamine (6-OHDA), and to clarify its molecular mechanism. Methods SH-SY5Y cells treated with retinoic acid (RA) were given 6-OHDA, mTORC2 signaling pathway inhibitor PP242 and agonist A-443654 respectively. The changes of cell number in each group were investigated by immunofluorescent staining; The total protein was extracted and the expression level and interaction of key proteins in mTORC2 signaling pathway were determined by Western blotting and co-immunoprecipitation (CoIP); The apoptosis rate of cells in each group was detected by flow cytometry. At the same time, the co-culture Parkinson’ s disease (PD) model was made using SH-SY5Y cell line and Bv-2 cell line; MTT colorimetric method was used to detect the cell viability of each group; ELISA was used to detect the content of tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) in cell culture supernatant. Results The number of tyrosine hydroxylase(TH) / proliferating cell nuclear antigen (PCNA) / hochest-, TH / 5-bronmo-2’ -deoxyuridine(BrdU) -labeled positive cells in 6-OHDA-lesioned PD cell model group was significantly lower than that in the normal group; The apoptosis rate was higher; The expression of Rictor, p-Akt and regulated in DNA damage and development 1(REDD1) was increased; There was an interaction between Rictor and p-Akt or REDD1; The cell viability was significantly reduced in the co-culture model; the content of TNF-α and IL-β increased in the cell culture supernatant. With further up-regulation of the abovementioned protein expressions, the cell survival, apoptosis and pro-inflammatory cytokine levels in A-443654 group were significantly ameliorated, while PP242 group showed the opposite changes. Conclusion A-443654 activates mTORC2 signaling pathway by p-Akt, which increases the expression of Rictor and REDD1 protein. These changes contribute to the amelioration in cell survival rate, apoptosis rate, and the proliferation and differentiation and decreasion of apoptosis rate of SH-SY5Y cells. These result improved 6-OHDA-induced cell damage and inhibited the release of pro-inflammatory cytokines.