AIM:To investigate whether uncoupling protein 2(UCP2) affects oleic acid-induced secretion of glucagonlike peptide-1(GLP-1) in L-cells.METHODS:mRNA and protein expression of UCP2 were analyzed in human NCI-H716 cells,...AIM:To investigate whether uncoupling protein 2(UCP2) affects oleic acid-induced secretion of glucagonlike peptide-1(GLP-1) in L-cells.METHODS:mRNA and protein expression of UCP2 were analyzed in human NCI-H716 cells,which serve as a model for enteroendocrine L-cells,by quantitative reverse transcription-polymerase chain reaction and Western blotting before and after treatment with oleic acid.Localization of UCP2 and GLP-1 in NCI-H716 cells was assessed by immunofluorescence labeling.NCI-H716 cells were transiently transfected with a small interfering RNA(siRNA) that targets UCP2(siUCP2) or with a nonspecific siRNA using Lipofectamine 2000.The concentrations of bioactive GLP-1 in the medium were measured by enzyme linked immunosorbent assay.RESULTS:Both GLP-1 and UCP2 granules were expressed mainly in the cytoplasm of NCI-H716 cells.NCI-H716 cells that secreted GLP-1 also expressed UCP2.Time-course experiments revealed that release of GLP-1 from NCI-H716 cells into the medium reached a maximum at 120 min and remained stable until at least 180 min after treatment with oleic acid(the level of GLP-1 increased about 2.3-fold as compared with the level of GLP-1 in the control cells,P < 0.05).In an experiment to determine dose dependence,stimulation of NCI-H716 cells with ≤ 8 mmol oleic acid led to a concentration-dependent release of GLP-1 into the medium;10 mmol oleic acid diminished the release of GLP-1.Furthermore,GLP-1 secretion induced by oleic acid from NCI-H716 cells that were transfected with siUCP2 decreased to 41.8%,as compared with NCI-H716 cells that were transfected with a non-specific siRNA(P < 0.01).CONCLUSION:UCP2 affected GLP-1 secretion induced by oleic acid.UCP2 plays an important role in L-cell secretion that is induced by free fatty acids.展开更多
Obesity-induced type 2 diabetes is mainly due to excessive free fatty acids leading to insulin resistance.Increasing thermogenesis is regarded as an effective strategy for hypolipidemia and hypoglycemia.Ginsenoside is...Obesity-induced type 2 diabetes is mainly due to excessive free fatty acids leading to insulin resistance.Increasing thermogenesis is regarded as an effective strategy for hypolipidemia and hypoglycemia.Ginsenoside is a natural active component in Panax ginseng C.A.Meyer,and some of them enhance thermogenesis.However,there are few studies on the mechanism and target of ginsenosides enhancing thermogenesis.Using thermogenic protein uncoupling protein 1(UCP1)-luciferase reporter assay,we identifi ed ginsenoside F1 as a novel UCP1 activator in the ginsenosides library.Using pull down assay and inhibitor interference,we found F1 binds toβ3-adrenergic receptors(β3-AR)to enhance UCP1 expression via cAMP/PKA/CREB pathway.We also investigated the ability of F1 on energy metabolism in obesity-induced diabetic mice,including body weight,body composition and energy expenditure.The results of proteomics showed that F1 signifi cantly up-regulated thermogenesis proteins and lipolytic proteins,but down-regulated fatty acid synthesis proteins.Ginsenoside F1 increased thermogenesis and ameliorated insulin resistance specifi cally by promoting the browning of white adipose tissue in obese mice.Additionally,ginsenoside F1 improves norepinephrine-induced insulin resistance in adipocytes and hepatocytes,and shows a stronger mitochondria respiration ability than norepinephrine.These fi ndings suggest that ginsenoside F1 is a promising lead compound in the improvement of insulin resistance.展开更多
Uncoupling protein 1 (UCP1) expressed by the brown adipose tissue (BAT) in the mitochondrial crista acts as a homeostatic thermogenerator of eutherians. The evaluation of UCP1 expression in the BAT offers significant ...Uncoupling protein 1 (UCP1) expressed by the brown adipose tissue (BAT) in the mitochondrial crista acts as a homeostatic thermogenerator of eutherians. The evaluation of UCP1 expression in the BAT offers significant scientific insight, especially in studies targeting limited areas such as the periarterial and pericardial regions of small experimental mammals. However, the negligible amount of this adipose tissue would render the general quantitative evaluation of the protein unreliable because of lipid contamination and low protein concentration. To address this problem, we quantitatively evaluated UCP1 expression in the mitochondrion of the mouse interscapular BAT using immunoelectron microscopy and immunohistochemical studies using a combination of primary and secondary antibodies in scheme A (rabbit anti-UCP1 IgG/gold particle-conjugated goat anti-rabbit IgG), B (rabbit IgG/gold particle-conjugated goat anti-rabbit IgG), C (rabbit anti-UCP1 IgG/gold particle-unconjugated goat anti-rabbit IgG), and D (rabbit IgG/gold particle-unconjugated goat anti-rabbit IgG). Scheme A shows the immunopositive reaction of obvious gold particles in the mitochondrial area, whereas other procedures revealed less distinctive reactions. The distinctive gold particle immunoreaction comprised electrical high-density spots with a mean diameter of >5 nm. However, in scheme B, the electrical high-density spots were scattered outside the mitochondrion and were significantly smaller than 4 nm;schemes C and D demonstrated few immunoreactions. Logistic regression analysis between schemes A and B showed that the threshold diameter of the electrical high-density spots measuring >5 nm indicated a true positive immunoreaction to anti-UCP1 antibody specifically in the mitochondrial area. Minor statistical difference was observed in the primary anti-UCP1 antibody between polyclonal IgG and monoclonal antibodies. Therefore, immunoelectron microscopy might be useful for evaluating negligible protein expression in some limited areas, such as UCP1 expression in the BAT of small experimental animals.展开更多
【目的】检测两个绵羊群体中解偶联蛋白1(uncoupling protein 1,UCP1)基因的单核苷酸多态性(single nucleotide polymorphism,SNP),预测和分析碱基改变对蛋白结构和功能的影响。【方法】利用PCR-SSCP结合测序的方法检测UCP1基因编码区的...【目的】检测两个绵羊群体中解偶联蛋白1(uncoupling protein 1,UCP1)基因的单核苷酸多态性(single nucleotide polymorphism,SNP),预测和分析碱基改变对蛋白结构和功能的影响。【方法】利用PCR-SSCP结合测序的方法检测UCP1基因编码区的SNPs,用生物信息学方法分析UCP1蛋白的理化性质和结构。【结果】UCP1基因编码区存在4个SNPs,其中c.214G>A(Val72Met)和c.273C>T位于外显子2,c.624C>T和c.757G>A(Ala253Thr)位于外显子5。进一步分析导致氨基酸改变的c.214G>A和c.757 G>A突变发现,此两个突变只对UCP1蛋白的理化性质和转录因子结合位点有细微改变,未引起UCP1蛋白空间构象的变化,对蛋白表达的影响不大。【结论】基于对人类中两个与肥胖相关的外显子突变型蛋白结构的比较说明,UCP1蛋白结构的改变可能影响其功能。展开更多
The visualization of symmetric structure by [18F]-FluoroDeoxyGlucose-Positron Emission Tomography (FDG-PET), corresponding to adipose density in computed tomography (CT), has led to the idea that Brown Adipose Tissue ...The visualization of symmetric structure by [18F]-FluoroDeoxyGlucose-Positron Emission Tomography (FDG-PET), corresponding to adipose density in computed tomography (CT), has led to the idea that Brown Adipose Tissue (BAT) could be present in adult human. This article studies the FDG uptake in a mice model deficient on Uncoupling Protein 1 (UCP1), in a simple thermal activation protocol. Methods: FDG were injected in mice, control and knock out (K.O.) for the UCP1. Before imaging mice were placed either in cold or warm environment. BAT uptake was evaluated by ratio named RISC. Results: In warm condition, mean value of the Ratio of Inter-Scapular uptake (RISC) was 1.34 +/﹣ 0.27. After cold exposure, RISC increased 2 fold for control mice, male K.O. did not increase their RISC, female K.O. increased their RISC up to 2.45. Conclusion: Our study brought a further confirmation that FDG-PET visualised activated Brown Adipose Tissue. It gives a direct proof of the role of UCP1 in this process. The FDG uptake by cold female K.O. mice was unexpected.展开更多
目的观察白虎加人参汤对2型糖尿病(type 2 diabetes mellitus,T2DM)MKR小鼠肠道解偶联蛋白2(uncoupling protein 2,UCP2)、AMP活化蛋白激酶(AMP-activated protein kinase,AMPK)表达及胰高血糖素样肽-1(glucagon like peptide-1,GLP-1)...目的观察白虎加人参汤对2型糖尿病(type 2 diabetes mellitus,T2DM)MKR小鼠肠道解偶联蛋白2(uncoupling protein 2,UCP2)、AMP活化蛋白激酶(AMP-activated protein kinase,AMPK)表达及胰高血糖素样肽-1(glucagon like peptide-1,GLP-1)分泌的影响,探讨其降糖机制。方法将MKR小鼠随机分为模型组和白虎加人参汤低、高剂量组,以FVB小鼠为空白组,中药干预4周后,观察小鼠糖代谢变化;ELISA法检测小鼠血清中胰岛素(insulin,INS)、GLP-1水平;RT-qPCR检测小鼠结肠AMPK、UCP2 mRNA水平;Western blot法检测小鼠结肠P-AMPKα、UCP2蛋白表达水平;组织形态学观察小鼠结肠组织病理形态及黏液量的变化。结果白虎加人参汤低、高剂量组与模型组比较,均能显著降低MKR小鼠的空腹血糖和INS水平(P<0.01);并能提高血清GLP-1浓度(P<0.01,P<0.05);上调小鼠结肠AMPK mRNA和P-AMPKα水平(P<0.01),下调UCP2 mRNA和蛋白水平(P<0.01)。白虎加人参汤低、高剂量组均能明显改善MKR小鼠结肠组织病理形态。结论白虎加人参汤可能通过抑制UCP2表达、激活AMPK的表达,促进肠道GLP-1的分泌,发挥治疗T2DM的作用。展开更多
基金Supported by Grant from the National Natural Science Foundation of China,No. 30771039
文摘AIM:To investigate whether uncoupling protein 2(UCP2) affects oleic acid-induced secretion of glucagonlike peptide-1(GLP-1) in L-cells.METHODS:mRNA and protein expression of UCP2 were analyzed in human NCI-H716 cells,which serve as a model for enteroendocrine L-cells,by quantitative reverse transcription-polymerase chain reaction and Western blotting before and after treatment with oleic acid.Localization of UCP2 and GLP-1 in NCI-H716 cells was assessed by immunofluorescence labeling.NCI-H716 cells were transiently transfected with a small interfering RNA(siRNA) that targets UCP2(siUCP2) or with a nonspecific siRNA using Lipofectamine 2000.The concentrations of bioactive GLP-1 in the medium were measured by enzyme linked immunosorbent assay.RESULTS:Both GLP-1 and UCP2 granules were expressed mainly in the cytoplasm of NCI-H716 cells.NCI-H716 cells that secreted GLP-1 also expressed UCP2.Time-course experiments revealed that release of GLP-1 from NCI-H716 cells into the medium reached a maximum at 120 min and remained stable until at least 180 min after treatment with oleic acid(the level of GLP-1 increased about 2.3-fold as compared with the level of GLP-1 in the control cells,P < 0.05).In an experiment to determine dose dependence,stimulation of NCI-H716 cells with ≤ 8 mmol oleic acid led to a concentration-dependent release of GLP-1 into the medium;10 mmol oleic acid diminished the release of GLP-1.Furthermore,GLP-1 secretion induced by oleic acid from NCI-H716 cells that were transfected with siUCP2 decreased to 41.8%,as compared with NCI-H716 cells that were transfected with a non-specific siRNA(P < 0.01).CONCLUSION:UCP2 affected GLP-1 secretion induced by oleic acid.UCP2 plays an important role in L-cell secretion that is induced by free fatty acids.
基金supported by the National Natural Science Foundation of China[31872674]the Jilin Talent Development Foundation Grant[20200301018RQ]the Fundamental Research Funds for the Central Universities[CGZH202206].
文摘Obesity-induced type 2 diabetes is mainly due to excessive free fatty acids leading to insulin resistance.Increasing thermogenesis is regarded as an effective strategy for hypolipidemia and hypoglycemia.Ginsenoside is a natural active component in Panax ginseng C.A.Meyer,and some of them enhance thermogenesis.However,there are few studies on the mechanism and target of ginsenosides enhancing thermogenesis.Using thermogenic protein uncoupling protein 1(UCP1)-luciferase reporter assay,we identifi ed ginsenoside F1 as a novel UCP1 activator in the ginsenosides library.Using pull down assay and inhibitor interference,we found F1 binds toβ3-adrenergic receptors(β3-AR)to enhance UCP1 expression via cAMP/PKA/CREB pathway.We also investigated the ability of F1 on energy metabolism in obesity-induced diabetic mice,including body weight,body composition and energy expenditure.The results of proteomics showed that F1 signifi cantly up-regulated thermogenesis proteins and lipolytic proteins,but down-regulated fatty acid synthesis proteins.Ginsenoside F1 increased thermogenesis and ameliorated insulin resistance specifi cally by promoting the browning of white adipose tissue in obese mice.Additionally,ginsenoside F1 improves norepinephrine-induced insulin resistance in adipocytes and hepatocytes,and shows a stronger mitochondria respiration ability than norepinephrine.These fi ndings suggest that ginsenoside F1 is a promising lead compound in the improvement of insulin resistance.
文摘Uncoupling protein 1 (UCP1) expressed by the brown adipose tissue (BAT) in the mitochondrial crista acts as a homeostatic thermogenerator of eutherians. The evaluation of UCP1 expression in the BAT offers significant scientific insight, especially in studies targeting limited areas such as the periarterial and pericardial regions of small experimental mammals. However, the negligible amount of this adipose tissue would render the general quantitative evaluation of the protein unreliable because of lipid contamination and low protein concentration. To address this problem, we quantitatively evaluated UCP1 expression in the mitochondrion of the mouse interscapular BAT using immunoelectron microscopy and immunohistochemical studies using a combination of primary and secondary antibodies in scheme A (rabbit anti-UCP1 IgG/gold particle-conjugated goat anti-rabbit IgG), B (rabbit IgG/gold particle-conjugated goat anti-rabbit IgG), C (rabbit anti-UCP1 IgG/gold particle-unconjugated goat anti-rabbit IgG), and D (rabbit IgG/gold particle-unconjugated goat anti-rabbit IgG). Scheme A shows the immunopositive reaction of obvious gold particles in the mitochondrial area, whereas other procedures revealed less distinctive reactions. The distinctive gold particle immunoreaction comprised electrical high-density spots with a mean diameter of >5 nm. However, in scheme B, the electrical high-density spots were scattered outside the mitochondrion and were significantly smaller than 4 nm;schemes C and D demonstrated few immunoreactions. Logistic regression analysis between schemes A and B showed that the threshold diameter of the electrical high-density spots measuring >5 nm indicated a true positive immunoreaction to anti-UCP1 antibody specifically in the mitochondrial area. Minor statistical difference was observed in the primary anti-UCP1 antibody between polyclonal IgG and monoclonal antibodies. Therefore, immunoelectron microscopy might be useful for evaluating negligible protein expression in some limited areas, such as UCP1 expression in the BAT of small experimental animals.
文摘The visualization of symmetric structure by [18F]-FluoroDeoxyGlucose-Positron Emission Tomography (FDG-PET), corresponding to adipose density in computed tomography (CT), has led to the idea that Brown Adipose Tissue (BAT) could be present in adult human. This article studies the FDG uptake in a mice model deficient on Uncoupling Protein 1 (UCP1), in a simple thermal activation protocol. Methods: FDG were injected in mice, control and knock out (K.O.) for the UCP1. Before imaging mice were placed either in cold or warm environment. BAT uptake was evaluated by ratio named RISC. Results: In warm condition, mean value of the Ratio of Inter-Scapular uptake (RISC) was 1.34 +/﹣ 0.27. After cold exposure, RISC increased 2 fold for control mice, male K.O. did not increase their RISC, female K.O. increased their RISC up to 2.45. Conclusion: Our study brought a further confirmation that FDG-PET visualised activated Brown Adipose Tissue. It gives a direct proof of the role of UCP1 in this process. The FDG uptake by cold female K.O. mice was unexpected.
文摘目的观察白虎加人参汤对2型糖尿病(type 2 diabetes mellitus,T2DM)MKR小鼠肠道解偶联蛋白2(uncoupling protein 2,UCP2)、AMP活化蛋白激酶(AMP-activated protein kinase,AMPK)表达及胰高血糖素样肽-1(glucagon like peptide-1,GLP-1)分泌的影响,探讨其降糖机制。方法将MKR小鼠随机分为模型组和白虎加人参汤低、高剂量组,以FVB小鼠为空白组,中药干预4周后,观察小鼠糖代谢变化;ELISA法检测小鼠血清中胰岛素(insulin,INS)、GLP-1水平;RT-qPCR检测小鼠结肠AMPK、UCP2 mRNA水平;Western blot法检测小鼠结肠P-AMPKα、UCP2蛋白表达水平;组织形态学观察小鼠结肠组织病理形态及黏液量的变化。结果白虎加人参汤低、高剂量组与模型组比较,均能显著降低MKR小鼠的空腹血糖和INS水平(P<0.01);并能提高血清GLP-1浓度(P<0.01,P<0.05);上调小鼠结肠AMPK mRNA和P-AMPKα水平(P<0.01),下调UCP2 mRNA和蛋白水平(P<0.01)。白虎加人参汤低、高剂量组均能明显改善MKR小鼠结肠组织病理形态。结论白虎加人参汤可能通过抑制UCP2表达、激活AMPK的表达,促进肠道GLP-1的分泌,发挥治疗T2DM的作用。
