ABSTRACT
Objective@#To investigate the effect of glycogen synthase kinase 3β (GSK3β) on the decreased expression of Bmal1 induced by amyloid-beta protein 31-35 (Aβ31-35) in HT22 cells.@*Methods@#HT22 mouse hippocampal cells were divided into control group, Aβ31-35 group and LiCl+Aβ31-35 group by random number table method in the present study. Cells were synchronized to G0/G1 phase by 1% serum starvation for 1 hour (circadian time 0 (CT0)). Cell viability was detected by the cell counting kit-8 assay. The mRNA expression of clock gene Bmal1 was examined by real-time PCR at different CT times. The expression of GSK3β and BMAL1 protein was detected by Western blotting.@*Results@#Compared with the control group, Aβ31-35 induced the decreased expression of Bmal1 mRNA; The expression of both Bmal1 mRNA and BMAL1 protein was decreased significantly at CT20 (Bmal1 mRNA: 0.38±0.06 vs 0.83±0.08, t=4.549, P=0.001; BMAL1 protein: 0.67±0.04 vs 1.00±0.04, t=5.943, P<0.001). In the Aβ31-35 group, GSK3β activity was increased and the ratio of phosphorylated GSK3βS9 to GSK3β was decreased compared to the control group (0.66±0.08 vs 1.02±0.14, t=2.217, P=0.025). Aβ31-35 decreased the viability of HT22 cells (71.85%±6.20% in the Aβ31-35 group vs 98.14%±2.68% in the control group, t=3.891, P=0.006), and the GSK3β inhibitor LiCl pretreatment effectively reversed the decline of the viability induced by Aβ31-35 (90.74%±5.74% in the LiCl+Aβ31-35 group vs 71.85%±6.20% in the Aβ31-35 group, t=3.412, P=0.010). LiCl (in the LiCl+Aβ31-35 group) increased the expression of Bmal1 mRNA and BMAL1 protein significantly at CT20 compared with the Aβ31-35 group (Bmal1 mRNA: 0.72±0.05 vs 0.38±0.06, t=4.378, P=0.001; BMAL1 protein: 0.90±0.04 vs 0.67±0.04, t=4.052, P=0.002).@*Conclusion@#Increased GSK3β activity involved in the decreased expression of Bmal1 induced by Aβ31-35 in HT22 cells.
ABSTRACT
Objective@#To investigate the effect of glycogen synthase kinase 3β (GSK3β) on the decreased expression of Bmal1 induced by amyloid-beta protein 31-35 (Aβ31-35) in HT22 cells.@*Methods@#HT22 mouse hippocampal cells were divided into control group, Aβ31-35 group and LiCl+Aβ 31-35 group by random number table method in the present study. Cells were synchronized to G0/G1 phase by 1% serum starvation for 1 hour (circadian time 0 (CT0)). Cell viability was detected by the cell counting kit-8 assay. The mRNA expression of clock gene Bmal1 was examined by real-time PCR at different CT times. The expression of GSK3β and BMAL1 protein was detected by Western blotting.@*Results@#Compared with the control group, Aβ31-35 induced the decreased expression of Bmal1 mRNA; The expression of both Bmal1 mRNA and BMAL1 protein was decreased significantly at CT20 (Bmal1 mRNA: 0.38±0.06 vs 0.83±0.08, t=4.549, P=0.001; BMAL1 protein: 0.67±0.04 vs 1.00±0.04, t=5.943, P<0.001). In the Aβ31-35 group, GSK3β activity was increased and the ratio of phosphorylated GSK3βS9 to GSK3β was decreased compared to the control group (0.66±0.08 vs 1.02±0.14, t=2.217, P=0.025). Aβ31-35 decreased the viability of HT22 cells (71.85%±6.20% in the Aβ31-35 group vs 98.14%±2.68% in the control group, t=3.891, P=0.006), and the GSK3β inhibitor LiCl pretreatment effectively reversed the decline of the viability induced by Aβ31-35 (90.74%±5.74% in the LiCl+Aβ31-35 group vs 71.85%±6.20% in the Aβ31-35 group, t=3.412, P=0.010). LiCl (in the LiCl+Aβ31-35 group) increased the expression of Bmal1 mRNA and BMAL1 protein significantly at CT20 compared with the Aβ31-35 group (Bmal1 mRNA: 0.72±0.05 vs 0.38±0.06, t=4.378, P=0.001; BMAL1 protein: 0.90±0.04 vs 0.67±0.04, t=4.052, P=0.002).@*Conclusion@#Increased GSK3β activity involved in the decreased expression of Bmal1 induced by Aβ31-35 in HT22 cells.
ABSTRACT
Objective To investigate the effect of glycogen synthase kinase 3β (GSK3β) on the decreased expression of Bmal1 induced by amyloid-beta protein 31-35 (Aβ31-35) in HT22 cells.Methods HT22 mouse hippocampal cells were divided into control group,Aβ31-35 group and LiCl+Aβ 31-35 group by random number table method in the present study.Cells were synchronized to G0/G1 phase by 1％ serum starvation for 1 hour (circadian time 0 (CT0)).Cell viability was detected by the cell counting kit-8 assay.The mRNA expression of clock gene Bmal1 was examined by real-time PCR at different CT times.The expression of GSK3β and BMAL1 protein was detected by Western blotting.Results Compared with the control group,Aβ31-35 induced the decreased expression of Bmal1 mRNA;The expression of both Bmal1 mRNA and BMAL1 protein was decreased significantly at CT20 (Bmal1 mRNA:0.38±0.06 vs 0.83±0.08,t=4.549,P=0.001;BMAL1 protein:0.67±0.04 vs 1.00±0.04,t=5.943,P＜0.001).In the Aβ31-35group,GSK3β activity was increased and the ratio of phosphorylated GSK3βS9 to GSK3β was decreased compared to the control group (0.66±0.08 vs 1.02±0.14,t=2.217,P=0.025).Aβ31-35 decreased the viability of HT22 cells (71.85％±6.20％ in the Aβ31-35 group vs 98.14％±2.68％ in the control group,t=3.891,P=0.006),and the GSK3β inhibitor LiC1 pretreatment effectively reversed the decline of the viability induced by Aβ31-35 (90.74％±5.74％ in the LiCl+Aβ31-35 group vs 71.85％±6.20％ in the Aβ31-35 group,t=3.412,P=0.010).LiCl (in the LiCl+Aβ31-35 group) increased the expression of Bmal1 mRNA and BMAL1 protein significantly at CT20 compared with the Aβ31-35 group (Bmal1 mRNA:0.72±0.05 vs 0.38±0.06,t=4.378,P=0.001;BMAL1 protein:0.90±0.04 vs 0.67±0.04,t=4.052,P=0.002).Conclusion Increased GSK3β activity involved in the decreased expression of Bmal 1 induced by Aβ31-35 in HT22 cells.
ABSTRACT
Objective To observe the effect of DA-JC1 on the circadian rhythm disorder in C57BL/6 mice and the abnormal expression of period1 in HT22 cells induced by amyloid β-protein 31-35 (Aβ31-35).Methods (1) The six-eight weeks old C57BL/6 male mice were selected for wheelrunning behavior experiment.Then we analyzed the effect of DA-JC1 on the circadian rhythm disorder induced by Aβ31-35.(2) HT22 mouse hippocampal cells were adopted as the research objects.Cells were divided into vehicle group,Aβ31-35 group,pre-DA-JC1 group and DA-JC1 group (n =4 respectively) by random number table method.Cell viability was assessed by methylthiazolyldiphenyl-tetrazolium bromide cytotoxicity assay.Real-time quantitative PCR was used to detect the expression of clock gene period1,and Western blotting was applied to examine the expression of period1 protein at circadian time (CT) 12.Results (1) Compared with the vehicle group ((23.54 ± 0.07) h),the circadian rhythm of mice in the Aβ31-35 group was disturbed which exhibited significantly longer free running period ((23.80 ± 0.06) h,t=0.265,P=0.010),whereas the disruption was significantly relieved with pre-treatment of DA-JC1 ((23.61 ± 0.06) h,t =0.193,P =0.047).(2) Compared with the vehicle group (100.0％ ± 3.6％),5 μmol/L Aβ31-35 decreased the cell viability significantly (78.7％ ± 3.4％,t =12.393,P =0.005),and DA-JC1 can reduce the toxicity of Aβ31-35 in HT22 cells (89.2％ ± 2.3％,t =9.748,P =0.048).(3) Compared with the vehicle group (period1 gene:1.00 ± 0.09;period1 protein:1.01 ± 0.07),abnormal rhythmic expression of period1 was induced by Aβ31-35 in HT22 cells which significantly decreased at CT12 (period1 gene:0.58 ± 0.04,t =0.419,P =0.001;period1 protein:0.74 ± 0.07,t =0.221,P =0.007) while DA-JC1 pre-treatment can reverse the abnormal expression (period1 gene:0.79 ±0.11,t =0.279,P=0.024;period1 protein:0.99 ±0.05,t=0.226,P=0.009).Conclusion DA-JC1 improves the circadian rhythm disorder induced by Aβ31-35 in C57BL/6 mice and improves the abnormal expression of period1 induced by Aβ31-35 in HT22 cells.