ABSTRACT
Objective To evaluate the effect of phosphatidylinositol-3 kinase inhibitor LY294002 combined with dichloroacetate on apoptosis in human pulmonary arterial smooth muscle cells (SMCs) and AKT/GSK-3β/HK-2 signaling pathway.Methods Human pulmonary arterial SMCs were seeded into culture plates at a density of 2 x 104 cells/ml after 3-5 passages.After being incubated for 72 h,the SMCs were cultured in the medium supplemented with 0.2％ fetal bovine serum for 24 h to induce starvation prior to experiments.The cells were then randomly divided into 6 groups (n =6 each) using a random number table:control group (group C),positive control group (group F),LY294002 group (group L),different concentrations of dichloroacetate groups (D1 and D2 groups),and LY294002 combined with dichloroacetate group (group LD1).In group C,the cells were cultured in the medium supplemented with 0.2％ fetal bovine serum.In F,L,D1,D2 and LD1 groups,the cells were cultured in the medium supplemented with 10％ fetal bovine serum.LY294002 2 μmol/L was added to the medium in group L.Dichloroacetate l0 and 20 mmol/L were added to the medium in D1 and D2 groups,respectively.In group LD1,LY294002 (2 μmol/L) was added,and 30 min later dichloroacetate 10 mmol/L was added to the medium in LD1 group.The cells were incubated for 48 h.Flow cytometry was used to measure the cell apoptosis and mitochondrial membrane potential.The expression of phosphorylated AKT (p-Akt),phosphorylated glycogen synthase kinase 3β (p-GSK-3β),and hexokinase-2 (HK-2) was detected using Western blot.Apoptosis rate was calculated.Results Compared with group C,apoptosis rate was significantly increased,and mitochondrial membrane potential was decreased in D2 and LD1 groups,the expression of p-Akt,p-GSK-3β and HK-2 was up-regulated in group F,and no significant changes were found in apoptosis rate and mitochondrial membrane potential in F,L and D1 groups.Compared with group D2,apoptosis rate was significantly increased,mitochondrial membrane potential was decreased,and the expression of p-Akt,p-GSK-3β and HK-2 was down-regulated in LD1 group.The expression of p-Akt,p-GSK-3β and HK-2 was significantly lower in D2 and LD1 groups than in group F.Conclusion LY294002 combined with dichloroacetate can promote apoptosis in human pulmonary arterial SMCs possibly through blocking AKT/GSK-3β/HK-2 signaling pathway.
ABSTRACT
Objective To observe the effects of histone deacetylases inhibitor (HDACi) on cognitive performance and cerebral tau phosphorylation in transgenic mice coexpressed five familial Alzheimer' s disease mutations (5XFAD).Method The total 12 5XFAD-CC and 12 wild type (WT) mice were administrated with suberoylanilide hydroxamic acid ( SAHA,n =7) and vehicle ( n =5 ),respectively.The cognitive performance was assessed by Y-maze and Morris water maze.The protein levels of acetylated α-tubulin,total tau and phosphorylated tau and phosphorylated glycogen synthase kinase-3β (GSK3β) were determined by Western blotting.Results SAHA ameliorated learning and memory deficits in 5XFAD-CC mice (39.10％ ±2.25％,t =2.688,P =0.0312 for total numbers of entrance in novel arm; 26.81％ ±0.78％,t =3.271,P =0.017 for time spending in novel arm; F =5.936,P =0.045 for hidden platform;31.70％ ±4.21％,t =2.317,P =0.049 for probe trial).Administration of SAHA significantly increased acetylated α-tubulin in hippocampus of WT and 5XFAD-CC mice (26.42％ and 29.64％,respectively).Additionally,SAHA attenuated tau-pSer396,tau-pSer404 and tau-pThrThr231 in hippocampus of 5XFAD-CC mice (24.22％,48.98％ and 26.95％,respectively). Moreover,hippocampal phosphorylated GSK3β was markedly reduced in SAHA-treated 5XFAD-CC mice (31.29％). Conclusion SAHA may improve cognitive performance in 5XFAD-CC mice, which is associated with its significant effects on the phosphorylation of tau and GSK3β.
ABSTRACT
Glycogen synthase kinase-3β (GSK-3β) is a serine/threonine protein kinase, which takes part not only in glycogen metabolism, but also in cell proliferation, differentiation and apoptosis. GSK-3β is inhibited by growth factors and hypertrophic stimuli through phosphorylation of its N-terminal end serine (Ser9) residue. It is also activated by phosphorylation of its tyrosine (Tyr216) residue. GSK-3β is profoundly inactivated in mice with hypertrophic cardiomyopathy (HCM) and plays a secondary role in myosin heavy chain mutation. However, the role of GSK-3β in HCM was controversial. Recent studies have demonstrated that the activation of GSK-3β inhibits the myocardial hypertrophy, and is regulated by Wnt/Frizzld and PI3-K/Akt signaling pathways. This article introduces the molecular role of glycogen synthase kinase-3β signaling in myocardial hypertrophy and the different pathways on the activity of glycogen synthase kinase-3β (GSK-3β)
ABSTRACT
Glycogen synthase kinase-3? (GSK-3?) is a serine/threonine protein kinase,which takes part not only in glycogen metabolism,but also in cell proliferation,differentiation and apoptosis. GSK-3? is inhibited by growth factors and hypertrophic stimuli through phosphorylation of its N-terminal end serine (Ser9) residue. It is also activated by phosphorylation of its tyrosine (Tyr216) residue. GSK-3? is profoundly inactivated in mice with hypertrophic cardiomyopathy (HCM) and plays a secondary role in myosin heavy chain mutation. However,the role of GSK-3? in HCM was controversial. Recent studies have demonstrated that the activation of GSK-3? inhibits the myocardial hypertrophy,and is regulated by Wnt/Frizzld and PI3-K/Akt signaling pathways. This article introduces the molecular role of glycogen synthase kinase-3? signaling in myocardial hypertrophy and the different pathways on the activity of glycogen synthase kinase-3? (GSK-3?)