Effects of fluoride exposure on autophagy and AMPK/mTOR/ULK1 pathway in NG108-15 cells / 中华地方病学杂志

Objective:To investigate the effects of fluoride exposure on autophagy and the expression levels of adenosine monophosphate activated protein kinase (AMPK), mammalian target of rapamycin (mTOR) and Unc-51-like kinase 1 (ULK1) in mouse neuroblastoma and rat glioma fusion cells (NG108-15 cells).Methods:NG108-15 cells were cultured in vitro and divided into control group (0 mg/L), low fluoride group (20 mg/L), medium fluoride group (40 mg/L) and high fluoride group (80 mg/L) according to the final concentration of sodium fluoride, and the cells were collected after 24 h of treatment for standby. NG108-15 cells autophagy was detected by immunofluorescence/immunocytochemistry (IF/ICC method, the autophagy positive control group was treated with chloroquine phosphate); the mRNA expression levels of AMPK, mTOR and ULK1 in each group were detected by real-time fluorescent quantitative polymerase chain reaction (qRT-PCR); the protein expression levels of autophagy related protein microtubule-associated protein 1 light chain 3B (LC3B), AMPK, mTOR, ULK1, phosphorylation (p)-AMPK, p-mTOR, p-ULK1 in each group were detected by Western blotting. Results:No autophagosome was detected in the control group, and autophagosomes were detected in all the fluoride groups. The protein expression level of LC3B in the low, medium and high fluoride groups (1.80 ± 0.59, 2.16 ± 0.60, 2.30 ± 0.57) was significantly higher than that in the control group (1.00 ± 0.29, P < 0.05). The results of qRT-PCR showed that compared with the control group, the mRNA expression levels of AMPK in medium and high fluoride groups were higher (2.30 ± 0.57, 4.41 ± 1.05 vs 1.00 ± 0.01, P < 0.05); the mRNA expression levels of mTOR in the low, medium and high fluoride groups were lower (0.79 ± 0.04, 0.76 ± 0.09, 0.64 ± 0.10 vs 1.00 ± 0.01, P < 0.05), and the mRNA expression levels of ULK1 were higher (1.81 ± 0.39, 1.96 ± 0.35, 4.22 ± 1.03 vs 1.00 ± 0.01, P < 0.05). The results of Western blotting showed that compared with the control group, the protein expression levels of AMPK (1.21 ± 0.05, 1.20 ± 0.04, 1.30 ± 0.07 vs 1.00 ± 0.03), p-AMPK (1.12 ± 0.05, 1.20 ± 0.06, 1.49 ± 0.07 vs 1.00 ± 0.02), ULK1 (1.16 ± 0.05, 1.26 ± 0.05, 1.15 ± 0.05 vs 1.00 ± 0.04) and p-ULK1 (1.19 ± 0.04, 1.17 ± 0.02, 1.24 ± 0.05 vs 1.00 ± 0.05) in the low, medium and high fluoride groups were higher ( P < 0.05), and the protein expression levels of mTOR were lower (0.77 ± 0.03, 0.60 ± 0.03, 0.55 ± 0.04 vs 1.00 ± 0.04, P < 0.05); the protein expression levels of p-mTOR in the medium and high fluoride groups were lower (0.93 ± 0.05, 0.48 ± 0.02 vs 1.00 ± 0.02, P < 0.05). Conclusion:Fluoride exposure can induce autophagy in NG108-15 cells, and the expression of AMPK and ULK1 are up-regulated, while the expression of mTOR is down-regulated.

Effects of Stilbene Glycoside on Okadaic Acid-induced Tau Protein Phosphorylation in NG 108-15 Cells / 中国药房

OBJECTIVE： To observe the effects of stilbene glycosidec （TSG） on okadaic acid （OA）-induced Tau protein phosphorylation in NG108-15 cells， and to investigate the potential anti-Alzheimer’s disease （AD） mechanism of this compound. METHODS： AD model of NG108-15 cells was induced by OA. The survival rate of NG108-15 cells was observed by MTT assay after pretreated with low-dose， medium-dose and high-dose of TSG （50， 100， 200 μmol/L）. The apoptosis of NG108-15 cells was detected by AO/EB double fluorescence staining. The protein and mRNA expression of CDK5 and GSK3β， and the protein expression of Tau and p-Tau were detected by Western blotting assay and RT-PCR. The distribution of CDK5， GSK3β and Tau protein were detected by immunofluorescence. RESULTS： The normal morphology of NG108-15 cells was observed in normal control group， but CDK5， GSK3β and Tau protein were not found or few was found. Contracted or globular early apoptotic cells were observed in model gorup； the distribution of CDK5， GSK3β and Tau protein was increased， while survival rate of the cells was decreased； protein and mRNA expression of CDK5 and GSK3β as well as ratio of the relative expression of p-Tau to that of Tau （p-Tau/Tau） were all increased significantly （P＜0.05 or P＜0.01）. After pretreatment of TSG， the distribution of early apoptotic cells as well as CDK5， GSK3β and Tau protein were all decreased to some extent in administration groups， while survival rates of the cells were increased significantly. Protein expression of CDK5 and p-Tau/Tau in medium-dose group and high-dose group as well as mRNA expression of CDK5， protein and mRNA expression of GSK3β in administration group were decreased significantly （P＜0.05）. CONCLUSIONS： TSG can protect against AD model cells， the effects of which may be associated with improving survival rate of the cells， down-regulating the protein expression and gene transcription level of phosphokinase CDK5 and GSK3β， inhibiting Tau protein phosphorylation.

Effect of modified Wendan decoction on expression of p-JNK and p-c-jun in cellular model of AD / 中华中医药杂志

Objective: To investigate the effect of Modified Wendan Decoction(MWD) on expression of p-JNK and p-c-Jun in cellular model of AD.Methods: NG108-15 cells were exposured to 5?mol/L A?25-35 for 24h to establish the cell model.After treating with contained-MWD serum,cells morphous were observed,survival rate was tested by MTT and cell apoptosis by FCM,the expression of p-JNK and p-c-Jun was measured by method of immuocytochemistry.Results: MWD obviously reduced the expression of p-JNK and p-c-Jun and cell's apoptotic rate.Compared with the model group,the expression of p-JNK and p-c-jun in the SP600125 group and the group treated with contained-MWD serum decreased significantly(P

Role of Protein kinase C in Desensitization of Somatostatin-induced Calcium Signalling in NG108-15 Cells / 대한내분비학회지

BACKGROUND: Activation of G-protein coupled-somatostatin receptors induces the release of calcium from inositol 1, 4, 5-trisphosphate-sensitive intracelluar stores. G-protein-coupled receptor signaling decreases with prolonged exposure to an agonist. SEBJECTS and METHODS: Fura-2-based digital Ca2+ imaging was used to study the effects of prolonged exposure to an agonist on the somatostatin-induced intracellular Ca2+ concentration([Ca2+]i) increases in NG108-15 cells, which were differentiated with CO2-independent medium and 10micrometer forskolin. RESULTS: Exposure to somatostatin(1micrometer) for 30 min completely desensitized the NG108-15 cells to a second somatostatin-induced response. The cells recovered gradually over 20 min following washout of the somatostatin. The desensitization was not due to depletion of the intracellular Ca2+ stores, and pretreatment for 30 min with bradykinin(100nM), which activates phospholipase C, or DADLE(D-Ala2-D-Leu5 enkephalin, 1microM), which activates phospholipase C, failed to cross-desensitize the somatostatin-evoked [Ca2+]i increases. Treatment with 8-cpt-cAMP(0.1mM) for 30min did not influence the somatostatin-induced[Ca2+]i increases. Phorbol 12, 13-dibutyrate(PdBu, 1microM) blocked the response completely. Down-regulation of PKC due to 24 h exposure of PdBu (1microM) inhibited the somatostatin-induced desensitization. CONCLUSION: Prolonged exposure of somatostatin to NG108-15 cells desensitized the somatostatin-induced release of Ca2+ from the intracelluar store, with protein kinase C also involved in the desensitization.

Enhancing effect of DHEA ON DbcAMP-induced cell differentiation / 中国药理学通报

Aim To observe whether DHEA has enhancing effect on DbcAMP -induced differentiation of NG108-15 cells, including neurite outgrowth, and study its possible mechanisms. Methods NG108-15 cells (a h ybrid cell line of mouse neuroblastoma and rat glioma) were used as a substitute for primary culture neuron in vitro. The morphology of NG108-15 cells was o bserved and neurite outgrowth was determined in an inversed microscope after treatme nt with various drugs. Gelatin-substrate gel electrophoresis was used to detect gelatinases (MMP-9 and MMP-2). Results ① DHEA and DbcAMP inhibited NG108-15 proliferation.②DHEA had enhancing effect on the promoting activity of neuronal differentiation and neurite outgrowth by DbcAMP. DbcAMP could increase neurite elongation of NG108-15 cells. Compared with this, the combined treatment with DHEA and DbcAMP significantly enhanced the neurite outgrowth of NG108-15 cells, including neurite length and numbers of cells with neurite, in a DHEA dose-dependent manner. ③ MMPs were involved in neuronal differentiation. DbcAMP induced the increase in MMP-9 and MMP-2 activities and such elevation was enhanced by DHEA in a dose-dependent manner. Conclusion DHEA enhances the effect of DbcAMP in promoting the neurite outgrowth of NG108-15 cells, which might be related to the increase in MMP-9 and MMP-2 activities.