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Objective:To investigate the role of stress-inducible protein Sestrin2 (Sesn2) in the improvement of insulin resistance in rat L6 skeletal muscle cells treated with liraglutide.Methods:The establishment of insulin resistance model of rat L6 skeletal muscle cells was induced by palmitate. The experimental cells were divided into control group(Con group), palmitate 0.6 mmol/L treatment group(PA group), palmitate 0.6 mmol/L+ liraglutide 10 nmol/L treatment group(PA+ Lir10 group), palmitate 0.6 mmol/L+ liraglutide 100 nmol/L treatment group(PA+ Lir100 group), and palmitate 0.6 mmol/L+ liraglutide 1 000 nmol/L treatment group(PA+ Lir1000 group). The cell counting kit 8(CCK8) method was used to detect the cell activity in each group. Western blotting was used to detect the expression levels of glucose transporter 4(GLUT4), protein kinase B(Akt), phosphorylated protein kinase B(p-Akt), and Sesn2 protein in L6 cells. L6 cells were transfected with siRNA to inhibit the expression of Sesn2. The cells were treated with palmitate and liraglutide. Western blotting was used to detect the expression levels of Sesn2, Akt, p-Akt, and GLUT4 protein in L6 cells.Results:Compared with Con group, the cell survival rate, p-Akt/Akt ratio, Sesn2, and GLUT4 protein expression in PA group decreased significantly( P<0.05). After liraglutide intervention, the cell activity, p-Akt/Akt ratio, Sesn2, and GLUT4 protein expression of PA+ Lir100 and PA+ Lir1000 groups was increased( P<0.05). After inhibiting the expression of Sesn2, p-Akt/Akt ratio and GLUT4 protein in transfected si-Sesn2 and treated with 0.6 mmol/L palmitate group(PA+ si-Sesn2 group) and transfected si-Sesn2 and treated with 0.6 mmol/L palmitate+ liraglutide 100 nmol/L group (Lir100+ PA+ si-Sesn2 group) were significantly lower than those in transfection negative group (si-Con group; P<0.05). Even after liraglutide intervention, compared with PA+ si-Sesn2 group, p-Akt/Akt ratio and GLUT4 protein expression level were not significantly increased in Lir100+ PA+ si-Sesn2 group ( P>0.05). Conclusions:Palmitate could induce the decrease of p-Akt/Akt ratio and GLUT4 protein expression in L6 cells. Liraglutide upregulates the expression of Sesn2, which leads to the increase of p-Akt/Akt ratio and GLUT4 protein expression and contributes to the improvement of insulin resistance.
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Chitooligosaccharide-zinc (COS·Zn) is a powerful anti-oxidant and anti-aging scavenger, whose anti-oxidative ability immensely exceeds vitamin C. Therefore, this study was aimed to investigate the protective effects of COS·Zn against premature ovarian failure (POF) and potential mechanisms. Female KM adult mice were divided into the following groups: a treatment group (150 mg·kg
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Animals , Female , Humans , Mice , Chitosan , NF-E2-Related Factor 2/genetics , Nuclear Proteins , Oligosaccharides , Primary Ovarian Insufficiency/drug therapy , Signal Transduction , ZincABSTRACT
Objective To investigate the potential role of Sestrin2 (SESN2) in regulating the apoptosis of dendritic cells (DCs) induced by high mobility group box-1 protein (HMGB1).Methods DCs (the murine DC cell line DC2.4) were cultured with or without HMGB1 stimulation (cultured with 10ng/ml HMGB1 for 8,24 and 48 hours,or cultured with HMGB1 for 48 hours at different concentrations of 1,10 and 100ng/ml,respectively,n=4).The protein level of SESN2,cleaved-caspase-3 and Bcl-2 were analyzed with Western blotting.Localization of SESN2 in cells was observed under confocal laser microscope (LSCM).Cell apoptosis was analyzed with flow cytometry.In addition,DC2.4 cells were transfected with lentivirus containing SESN2 LV-RNA,SESN2 siRNA sequence expressing plasmids or blank vector (NC,NS,n=4).These cells were then stimulated with HMGB1 (100ng/ml)for 48 hours,and the apoptosis was accessed as mentioned above.Results Compared with the control group,the expression of SESN2 was obviously up-regulated after HMGB1 (10ng/ml) stimulation for 24 and 48 hours (P＜0.05).In a dose-dependent response,the expression of SESN2 was markedly enhanced in treatment with 1,10,100ng/ml HMGB1 for 48 hours (P＜0.05).Compared with the control group (7.35％ ± 1.33％),the percentage of apoptosis was significantly increased with 10,100ng/ml HMGB1 for 48 hours [(17.02％ ± 4.85％,17.48％ ± 4.04％,respectively,P＜0.05 or P＜0.01].After transfection,compared with blank vector group,the apoptosis of SESN2 siRNA group obviously elevated [(65.96％ ± 2.50％) vs.(50.01％ ± 2.07％),P＜0.05],and cleaved-caspase-3 expression significantly increased while Bcl-2 expression obviously decreased.In SESN2 LV-RNA group,the apoptosis significantly decreased [(35.57％ ± 1.69％) vs.(49.04％ ± 4.87％),P＜0.05],and cleaved-caspase-3 expression decreased and Bcl-2 expression obviously increased compared with blank vector group (P＜0.05).Conclusion SESN2 has a protective effect against HMGB 1 induced apoptosis of D C2.4 cells.
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Objective To explore the role of Sestrin2 in pulmonary alveolar type II epithelial cell injury induced by cigarette smoking and its mechanism of action. Methods The cell injury model was induced by cigarette smoke extract (CSE)in the human pulmonary alveolar type II epithelial A549 cells. The generation of ROS was detected by DCFDA fluorescence probe. The levels of inflammatory factors TNF-α and IL-8 were determined by ELISA, and the expression of Sestrin2 and the peroxiredoxin,Prx-SO2/3H,was detected by Western blot. In addition,all the events were also measured in the A549 cells which were transfected with Sestrin2 siRNA and treated with azithromycin. Results After the CSE treatment,the expression of Sestrin2 in the A549 cells was decreased, the expression of Prx-SO2/3H was increased, the ROS production,secretion of cytokines TNF-α and IL-8 were increased(P < 0.05). These changes were partly reducedby azithromycin, indicating that azithromycin significantly relieved CSE-induced oxidative stress and inflammatory injury.Silencing of Sestrin2 in the A549 cells result ed in an increase of Prx-SO2/3 H expression, ROS production and the secretionof the cytokines TNF-α and IL-8. However, oxidative stress and inflammatory injury were not alleviated with the addition ofazithromycin in the Sestrin2 siRNA silencing A549 cells. Conclusions Sestrin2 plays an protective role in the pulmonaryalveolar type II epithelial cell injury induced by cigarette smoking through negatively regulating the level of intracellularROS via catalyzing the reduction of the hyperoxidized peroxiredoxin Prx-SO2/3 H.