Our recent studies with cultured retinal pigment epithelium cells suggested that overexpression of interleukin 17 receptor C（IL-17RC）,a phenomenon observed in peripheral blood and chorioretinal tissues with age-rela...Our recent studies with cultured retinal pigment epithelium cells suggested that overexpression of interleukin 17 receptor C（IL-17RC）,a phenomenon observed in peripheral blood and chorioretinal tissues with age-related macular degeneration（AMD）,was associated with altered activation of phosphatidylinositide 3-kinase（PI3K）,Akt,and glycogen synthase kinase 3（GSK3）.We wondered whether or not altered PI3 K,Akt,and GSK3 activities could be detected in peripheral blood mononuclear cells（PBMC） obtained from AMD patients.In the patients＇ PBMC,absent or reduced serine-phosphorylation of GSK3α or GSK3β was observed,which was accompanied with increased phosphorylation of GSK3 substrates（e.g.CCAAT enhancer binding protein a,insulin receptor substrate 1,and TAU）,indicative of enhanced GSK3 activation.In addition,decreased protein mass of PI3K85α and tyrosinephosphorylation of PI3K50α was present in PBMC of the AMD patients,suggesting impaired PI3 K activation.Moreover,abnormally lowered molecular weight forms of Akt and GSK3 were detected in PBMC of the AMD patients.These data demonstrate that despite the presence of high levels of IL-17 RC,Wnt-3a and vascular endothelial growth factor,the PI3K/Akt/GSK3 signaling pathway is insensitive to these stimuli in PBMC of the AMD patients.Thus,measurement of PI3K/Akt/GSK3 expression and activity in PBMC may serve as a surrogate biomarker for AMD.展开更多
Phosphatidylinositide 3-kinase （PI3K）/protein kinase B （PKB, Akt） pathway plays a major role in proliferation and survival of many types of cells. The inhibitory effect of LY294002, widely ap- plied as an inhibito...Phosphatidylinositide 3-kinase （PI3K）/protein kinase B （PKB, Akt） pathway plays a major role in proliferation and survival of many types of cells. The inhibitory effect of LY294002, widely ap- plied as an inhibitor of PI3K, in combination with gemcitabine on proliferation of PANC-1 ceils was investigated. The expression of PI3K, phosphorylated AM （p-Akt） and multidrng-resistance like protein （MRP） in normal pancreas tissues, chronic pancreatitis tissues and pancreatic carcinoma tissues was de- tected. The effects of LY294002 combined with gemcitabine on proliferation of PANC-1 cells and pro- tein levels of p-Akt and MRP were detected. The results showed that the positive expression rate of PI3K, p-Akt and MRP in pancreatic carcinoma tissues was significantly higher than that in normal pan- creas tissues and chronic pancreatitis tissues （P〈0.01 and P〈0.05 respectively）. LY294002 could effec- tively enhance the inhibitory effect of gemcitabine on proliferation of PANC-1 cells. Furthermore, Western blotting revealed that LY294002 combined with gemcitabine reduced the protein levels of p-Akt and MRP, which contributed to the inhibition of proliferation. It is concluded that LY294002 in combination with gemcitabine may represent an alternative therapy for pancreatic carcinoma.展开更多
Objective:To investigate whether peroxisome proliferator-activated receptorγ(PPARγ)agonists,rosiglitazone and GW1929,activate the phosphatidylinositol 3-kinase(PI3K)-AKT/protein kinase B pathway and the mitogen-acti...Objective:To investigate whether peroxisome proliferator-activated receptorγ(PPARγ)agonists,rosiglitazone and GW1929,activate the phosphatidylinositol 3-kinase(PI3K)-AKT/protein kinase B pathway and the mitogen-activated protein kinase(MAPK)/extracellular signal-regulated kinase1/2(ERK1/2)pathway by upgrading the expression of chemerin.Methods:The HTR-8/SVneo trophoblastic cells were cultured in vitro in high glucose concentration(25 mmol/L)to mimic gestational diabetic phenotypes.We transfected small interfering RNA into HTR-8/SVneo cells to silence two receptors of chemerin,that are chemokine-like receptor 1(CMKLR1)and G protein-coupled receptor1(GPR1).And recombinant human chemerin,PPARγagonists(rosiglitazone,10μmol/L and GW1929,10μmol/L)and PPARγinhibitor(GW9662,5μmol/L)were additionally added to the medium,respectively.The existence of chemerin was verified by immunocytochemistry,and the expressions of PPARγ,chemerin,and its receptors as well as insulin signaling-related factors PI3K,AKT2,and MAPK(ERK1/2)were detected by real time quantitative-polymerase chain reaction and western blot.Results:Chemerin existed in the HTR-8/SVneo cells.Effects of chemerin on PI3K-AKT pathway and MAPK(ERK1/2)pathway were dependent on the density of chemerin.When rosiglitazone and GW1929 were added to the medium,the mRNA levels of PI3K,AKT2,and MAPK1 were upregulated(P<0.05).Conversely,GW9662 downregulated the mRNA levels of AKT2 and MAPK1(P<0.05).Rosiglitazone and GW1929 increased the protein levels of PPARγ,chemerin,CMKLR1 and GPR1(P<0.05).Rosiglitazone and GW1929 had no effect on the expression of PI3K p110βand phospho-AKT2 without CMKLR1(P>0.05).Meanwhile,the expression of phospho-ERK2 remained unaffected in the absence of GPR1(P>0.05).Conclusion:Both rosiglitazone and GW1929 have the effect of improving insulin signaling pathways via upgrading the level of chemerin in high glucose treated HTR-8/SVneo cells.展开更多
基金supported by intramural research funding of National Center for Complementary and Alternative Medicine(now is National Center for Complementary and Integrative Health),NIH,the US Department of Health and Human Services(to X.L.)and an operating grant(MOP 123279)from Canadian Institutes for Health Research(to Z.Y.)
文摘Our recent studies with cultured retinal pigment epithelium cells suggested that overexpression of interleukin 17 receptor C（IL-17RC）,a phenomenon observed in peripheral blood and chorioretinal tissues with age-related macular degeneration（AMD）,was associated with altered activation of phosphatidylinositide 3-kinase（PI3K）,Akt,and glycogen synthase kinase 3（GSK3）.We wondered whether or not altered PI3 K,Akt,and GSK3 activities could be detected in peripheral blood mononuclear cells（PBMC） obtained from AMD patients.In the patients＇ PBMC,absent or reduced serine-phosphorylation of GSK3α or GSK3β was observed,which was accompanied with increased phosphorylation of GSK3 substrates（e.g.CCAAT enhancer binding protein a,insulin receptor substrate 1,and TAU）,indicative of enhanced GSK3 activation.In addition,decreased protein mass of PI3K85α and tyrosinephosphorylation of PI3K50α was present in PBMC of the AMD patients,suggesting impaired PI3 K activation.Moreover,abnormally lowered molecular weight forms of Akt and GSK3 were detected in PBMC of the AMD patients.These data demonstrate that despite the presence of high levels of IL-17 RC,Wnt-3a and vascular endothelial growth factor,the PI3K/Akt/GSK3 signaling pathway is insensitive to these stimuli in PBMC of the AMD patients.Thus,measurement of PI3K/Akt/GSK3 expression and activity in PBMC may serve as a surrogate biomarker for AMD.
文摘Phosphatidylinositide 3-kinase （PI3K）/protein kinase B （PKB, Akt） pathway plays a major role in proliferation and survival of many types of cells. The inhibitory effect of LY294002, widely ap- plied as an inhibitor of PI3K, in combination with gemcitabine on proliferation of PANC-1 ceils was investigated. The expression of PI3K, phosphorylated AM （p-Akt） and multidrng-resistance like protein （MRP） in normal pancreas tissues, chronic pancreatitis tissues and pancreatic carcinoma tissues was de- tected. The effects of LY294002 combined with gemcitabine on proliferation of PANC-1 cells and pro- tein levels of p-Akt and MRP were detected. The results showed that the positive expression rate of PI3K, p-Akt and MRP in pancreatic carcinoma tissues was significantly higher than that in normal pan- creas tissues and chronic pancreatitis tissues （P〈0.01 and P〈0.05 respectively）. LY294002 could effec- tively enhance the inhibitory effect of gemcitabine on proliferation of PANC-1 cells. Furthermore, Western blotting revealed that LY294002 combined with gemcitabine reduced the protein levels of p-Akt and MRP, which contributed to the inhibition of proliferation. It is concluded that LY294002 in combination with gemcitabine may represent an alternative therapy for pancreatic carcinoma.
基金This study was supported by the National Key R&D Program of China(No.2016YFC1000405 and No.2018YFC1002903)
文摘Objective:To investigate whether peroxisome proliferator-activated receptorγ(PPARγ)agonists,rosiglitazone and GW1929,activate the phosphatidylinositol 3-kinase(PI3K)-AKT/protein kinase B pathway and the mitogen-activated protein kinase(MAPK)/extracellular signal-regulated kinase1/2(ERK1/2)pathway by upgrading the expression of chemerin.Methods:The HTR-8/SVneo trophoblastic cells were cultured in vitro in high glucose concentration(25 mmol/L)to mimic gestational diabetic phenotypes.We transfected small interfering RNA into HTR-8/SVneo cells to silence two receptors of chemerin,that are chemokine-like receptor 1(CMKLR1)and G protein-coupled receptor1(GPR1).And recombinant human chemerin,PPARγagonists(rosiglitazone,10μmol/L and GW1929,10μmol/L)and PPARγinhibitor(GW9662,5μmol/L)were additionally added to the medium,respectively.The existence of chemerin was verified by immunocytochemistry,and the expressions of PPARγ,chemerin,and its receptors as well as insulin signaling-related factors PI3K,AKT2,and MAPK(ERK1/2)were detected by real time quantitative-polymerase chain reaction and western blot.Results:Chemerin existed in the HTR-8/SVneo cells.Effects of chemerin on PI3K-AKT pathway and MAPK(ERK1/2)pathway were dependent on the density of chemerin.When rosiglitazone and GW1929 were added to the medium,the mRNA levels of PI3K,AKT2,and MAPK1 were upregulated(P<0.05).Conversely,GW9662 downregulated the mRNA levels of AKT2 and MAPK1(P<0.05).Rosiglitazone and GW1929 increased the protein levels of PPARγ,chemerin,CMKLR1 and GPR1(P<0.05).Rosiglitazone and GW1929 had no effect on the expression of PI3K p110βand phospho-AKT2 without CMKLR1(P>0.05).Meanwhile,the expression of phospho-ERK2 remained unaffected in the absence of GPR1(P>0.05).Conclusion:Both rosiglitazone and GW1929 have the effect of improving insulin signaling pathways via upgrading the level of chemerin in high glucose treated HTR-8/SVneo cells.
