Effects of rhGLP-1 (7-36) on Akt/GSK3 signaling pathway in hepatocytes / 中华内分泌外科杂志

Objective:To observe the effect of rhGLP-1 (7-36) on Akt/GSK3 signaling pathway in hepatocytes.Methods:Human HL7702 cell line was cultured to the logarithmic growth stage and divided into experimental group and blank control group. The cultures were incubated with 100nM medium containing rhglp-1 (7-36) and without rhglp-1 (7-36) for 90min. The levels of Akt, Glycogen synthase Kinase 3 (GSK3) and Glycogen synthase (GS) in the two groups were detected by Western Blot.Results:Compared with blank control group, the protein expression of p-Akt (Thr308) in experimental group (1.81±0.28) was significantly increased ( P=0.01), but the protein expression of Akt and p-Akt (Ser473) was not significantly changed. The protein expression levels of p-GSK3α (Ser21) (1.27±0.09) and p-GSK3β (Ser9) (1.24±0.09) in the experimental group were significantly increased ( P=0.003, 0.002), while the protein expression levels of GSK3α and GSK3β were not significantly changed. The protein expression level of p-GS (Ser641) (0.70±0.16) was decreased in the experimental group ( P=0.03), but the protein expression level of GS did not change significantly. Conclusion:Glp-1 can inhibit GSK3/GS signaling pathway, activate GS activity and promote glycogen synthesis.

Lithocarpus polystachyus (Sweet Tea) water extract promotes human hepatocytes HL7702 proliferation through activation of HGF/AKT/ERK signaling pathway / 中草药·英文版

Objective: Sweet Tea (ST), derived from the leaves of Lithocarpus polystachyus, is a Chinese folk medicine with wide pharmacological activities. However, the promotive effects of ST water extract on hepatocytes proliferation and its underlying mechanism remains still unknown. In the present study, the beneficial effects of ST water extract on human hepatocytes and its possible mechanism were investigated. Methods: MTT assay was used to detect the safety range of ST; HL7702 cells were divided into four groups: control group, ST low- (50 μg/mL), medium- (200 μg/mL) and high-concentration (800 μg/mL) groups; BrdU ELISA and EDU staining were used to observe DNA content and cell proliferation; Moreover, flow cytometry was applied to analyze the distribution of cell cycle. Furthermore, the expression of cyclin D1, CDK4, HGF/c-Met, Akt, Erk1/2 were detected by Western blot. Results: It was found that ST water extract concentration-dependent promoted human hepatocytes HL7702 cell proliferation within 72 h through accumulating the cells in S phase and G2/M phase. Furthermore, ST water extract up-regulated expression of Cyclin D1 and CDK4 proteins. Moreover, ST water extract not only increased HGF expression and phosphorylation of c-Met level, but also activated the phosphorylation levels of AKT, ERK1/2. Interestingly, both of AKT inhibitor A6730 and ERK1/2 inhibitor U0126 reversed the promotive effects of ST water extract, which further confirmed that activation of AKT and ERK1/2 were involved. Conclusion: The findings reveal that ST water extract promoted HL7702 cells proliferation through the stimulation of cell cycle mediated by activating the AKT- and ERK1/2-related pathway.