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[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.
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Aim To investigate the molecular mecha-nism of mTORC1/2 inhibitor PP242, which inhibiting cholangiocyte cell preliferation and cystic diliatation via inducing apoptosis and autophagy in the polycystic kid-ney ( PCK ) rats. Methods The expression of p-mTOR and p-Akt in the bile duct epithelial cells was examined by immunohistochemistry. The inhibiting effect of rapamycin and PP242 on cell proliferation ac-tivity on bile duct epithelial cells, the effect of gene si-lence on LC3, Beclin-1 and the effect of the authoph-agy-specific inhibitor 3-methyladenine (3-MA) on cell proliferation were respectively analyzed by WST-1 as-say. The expression of PI3K/Akt signaling pathway re-lated proteins, autophagy-related proteins LC3, Bec-lin-1 and clevead caspase-3, which were treated by PP242 were determined by Western blot. The effect of PP242 on apoptosis was detected by Annexin V/PI double staining and ELISA. The expression of LC3 in cytoplasm was detected by immunofluorescence. The a-bility of rat bile duct epithelial cells spheroid formation was detected by 3D cell culture method, and the cells were treated by single applied with rapamycin and ap- plied rapamycin combined with Rictor gene silencing respectively. Results The protein levels of p-Akt and p-mTOR markedly increased in the bile duct epitheli-um of PCK rats. PP242 inhibited the proliferation of bile duct epithelial cells more effectively than rapamy-cin and showed a dose-and time-dependent manner ( P<0.05 ) . PP242 significantly reduced the levels of PI3K/Akt signaling pathway-related proteins in PCK rat cholangiocytes. PP242 induced apoptosis and auto-phagy, up-regulated the levels of cleaved caspase-3, Beclin-1 and increased the ratio of LC3-II/LC3-I. The combination of Rictor gene silencing and rapamycin was more effective than rapamycin alone in inhibiting cholangiocytes in PCK rats. The inhibitory effect of PP242 on the cell viability was significantly weakened by treatment with 3-MA and knockdown of LC3 and Beclin-1 ( P <0.05 ) . Conclusions PP242 inhibits the proliferation of PCK rat cholangiocytes through PI3K/Akt/mTOR signaling pathway, and the mecha-nism is closely related with autophagy and apoptosis.
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Objective To explore the effects of PP242 on the expression of apoptosis protein Bcl?2 in human lens epithelial cells(HLECs). Meth?ods Immortal HLECs SRA01/04 were cultured and treated with different concentrations of PP242. The cell growth was examined by MTT assay at 24 h and 48 h after PP242 treatment. Real?time quantitative polymerase chain reaction(RT?PCR)and Western blot were adopted to detect the mRNA and protein expression of Bcl?2 respectively. Results The cultured HLECs SRA01/04 were collected and treated with different concentra?tions(100,250,500,750,1 000,1 500 nmol/L)of PP242. After treatment for 24 h and 48 h,the inhibitory rate in each well was determined by MTT assay. The inhibition rate was as below,24 h:7.55%,9.43%,16.98%,22.64%,26.42%,30.19%;48 h:11.11%,23.81%,36.51%,42.86%, 49.21%,63.49%. Compared with the control group,the difference was statistically significant(P<0.05). Compared with the control group(0 nmol/L),the expression of Bcl?2 protein was significantly decreased with the increasing concentrations of PP242(P<0.05),while the expression of Bcl?2 mRNA was inhibited by PP242 based on the results of RT?PCR. Compared with the control group(0 nmol/L),the RT?PCR results of Bcl?2 mRNA were 0.723±0.039,0.517±0.028,0.353±0.052,0.167±0.046,respectively(P<0.05). Conclusion PP242 could inhibit cell proliferation of HLECs in vitro with a concentration and time depended manner. Bcl?2 protein is expressed in HLECs,which could be down regulated by PP242 treatment.