目的本研究目的是构建一种能稳定表达绿色荧光蛋白(GFP)人胰高血糖素样肽-1受体(GLP1R)的胰岛细胞系,用来筛选GLP1R激动剂类药物。方法使用X-treme GENE HP DNA Transfection Reagent将pCMV6-AC-GLP1R-GFP质粒转染到Rin-m5F细胞,经G418...目的本研究目的是构建一种能稳定表达绿色荧光蛋白(GFP)人胰高血糖素样肽-1受体(GLP1R)的胰岛细胞系,用来筛选GLP1R激动剂类药物。方法使用X-treme GENE HP DNA Transfection Reagent将pCMV6-AC-GLP1R-GFP质粒转染到Rin-m5F细胞,经G418筛选单克隆Rinm5F/GLP1R-GFP细胞并扩大培养。结果该细胞能稳定传代,荧光显微镜下观察细胞绿色荧光分布均匀,Western blot验证GLP1R蛋白表达显著增加。在实验验证中,对照空白组中细胞绿色荧光分布均匀,阴性药物格列本脲(非GLP1R靶点药物)作用时细胞内无明显荧光斑点出现,阳性药物百泌达作用(GLP1R激动剂类药物)时细胞内出现显著荧光斑点。结论 GLP1R激动剂类药物筛选模型Rin-m5F/GLP1R-GFP成功构建。该模型能对混合物样品进行筛选,具有假阳性极低、筛选所需样本小、筛选样品量大、易标准化、筛选速度快、特异性强等优势,为GLP1R激动剂类药物的筛选奠定了基础。展开更多
Prostaglandin E-2(PGE(2)) is a well-known mediator of beta-cell dysfunction in both type 1 and type 2 diabetes.We recently reported that down-regulation of the Akt pathway activity is implicated in PGE(2)-induced panc...Prostaglandin E-2(PGE(2)) is a well-known mediator of beta-cell dysfunction in both type 1 and type 2 diabetes.We recently reported that down-regulation of the Akt pathway activity is implicated in PGE(2)-induced pancreatic beta-cell dysfunction.The aim of this study was to further dissect the signaling pathway of this process in pancreatic beta-cell line HIT-T15 cells and primary mouse islets.We found that PGE(2) time-dependently increased the c-Jun N-terminal kinase(JNK) pathway activity.JNK inhibition by the JNK-specific inhibitor SP600125 reversed PGE(2)-inhibited glucose-stimulated insulin secretion(GSIS).PGE(2) induced dephosphorylation of Akt and FOXO1, leading to nuclear localization and transactivation of FOXO1.Activation of FOXO1 induced nuclear exclusion but had no obvious effect on the whole-cell protein level of pancreatic and duodenal homeobox 1(PDX1).However, these effects were all attenuated by JNK inhibition.Furthermore, adenovirus-mediated overexpression of dominant-negative(DN)FOXO1 abolished whereas constitutively active(CA)-FOXO1 mimicked the effects of PGE(2) on GSIS in isolated mouse islets.In addition, we demonstrated that DN-JNK1 but not DN-JNK2 or CA-Akt abolished the PGE(2)-induced AP-1 luciferase reporter activity, whereas DN-JNK1 and CA-Akt but not DN-JNK2 reversed the effect of PGE(2) on FOXO1 transcriptional activity, and overexpression of DN-JNK1 rescued PGE(2)-impaired GSIS in mouse islets.Our results revealed that activation of the JNK is involved in PGE(2)induced beta-cell dysfunction.PGE(2)-mediated JNK1 activation, through dephosphorylation of Akt and FOXO1, leads to nuclear accumulation of FOXO1 and nucleocytoplasmic shuttling of PDX1, finally resulting in defective GSIS in pancreatic beta-cells.展开更多
基金supported by the National High-Tech R&D Program of China(“863”Program)(2009AA22704)the National Natural Science Foundation of China(30873089,81173129)+3 种基金the Program for Changjiang Scholars and Innovative Research Team in University(IRT0946)the Open Foundation of Innovative Platform in University of Hunan Province of China(10K078)the Science and Technology Plan Key Grant of Hunan Province of China(2009TP40682)the Fundamental Research Funds for the Central Universities(201023100001)
文摘目的:在细胞水平研究烟酰胺单核苷酸(nicotinamide mononucleotide,NMN)对胰岛素分泌的调节作用及其对与胰岛素分泌相关的重要转录因子胰十二指肠同源盒基因(pancreatic and duodenalhomeobox-1,PDX-1)和分叉头框家族转录因子1(forkhead box-containing protein O-1,FoxO1)基因表达的影响。方法:采用大鼠胰岛素ELISA试剂盒检测RIN-m5f细胞胰岛素分泌水平。用Real-time PCR检测RIN-m5f细胞PDX-1和FoxO1的mRNA表达水平。用Western印迹检测RIN-m5f细胞PDX-1蛋白表达水平。结果:用瑞格列奈10 nmol/L+NMN 100μmol/L处理RIN-m5f细胞48 h,与空白对照及DMSO对照组相比,胰岛素分泌量均显著增高(P<0.05);与NMN 50μmol/L组比较,胰岛素分泌量的增高也有统计学意义(P<0.05)。10,50和100μmol/L的NMN作用RIN-m5f细胞36 h,PDX-1的mRNA表达量均上调(依次为P<0.05,P<0.01,P<0.001)。100μmol/L剂量组与10μmol/L和50μmol/L剂量组比较差异也有统计学意义(P<0.001)。50,100和200μmol/L的NMN作用RIN-m5f细胞36或48 h,PDX-1的蛋白表达量与对照组比较差异无统计学意义(P>0.05)。结论:NMN可以调控RIN-m5f细胞中胰岛素的分泌及PDX-1的mRNA表达水平。
文摘目的本研究目的是构建一种能稳定表达绿色荧光蛋白(GFP)人胰高血糖素样肽-1受体(GLP1R)的胰岛细胞系,用来筛选GLP1R激动剂类药物。方法使用X-treme GENE HP DNA Transfection Reagent将pCMV6-AC-GLP1R-GFP质粒转染到Rin-m5F细胞,经G418筛选单克隆Rinm5F/GLP1R-GFP细胞并扩大培养。结果该细胞能稳定传代,荧光显微镜下观察细胞绿色荧光分布均匀,Western blot验证GLP1R蛋白表达显著增加。在实验验证中,对照空白组中细胞绿色荧光分布均匀,阴性药物格列本脲(非GLP1R靶点药物)作用时细胞内无明显荧光斑点出现,阳性药物百泌达作用(GLP1R激动剂类药物)时细胞内出现显著荧光斑点。结论 GLP1R激动剂类药物筛选模型Rin-m5F/GLP1R-GFP成功构建。该模型能对混合物样品进行筛选,具有假阳性极低、筛选所需样本小、筛选样品量大、易标准化、筛选速度快、特异性强等优势,为GLP1R激动剂类药物的筛选奠定了基础。
文摘Prostaglandin E-2(PGE(2)) is a well-known mediator of beta-cell dysfunction in both type 1 and type 2 diabetes.We recently reported that down-regulation of the Akt pathway activity is implicated in PGE(2)-induced pancreatic beta-cell dysfunction.The aim of this study was to further dissect the signaling pathway of this process in pancreatic beta-cell line HIT-T15 cells and primary mouse islets.We found that PGE(2) time-dependently increased the c-Jun N-terminal kinase(JNK) pathway activity.JNK inhibition by the JNK-specific inhibitor SP600125 reversed PGE(2)-inhibited glucose-stimulated insulin secretion(GSIS).PGE(2) induced dephosphorylation of Akt and FOXO1, leading to nuclear localization and transactivation of FOXO1.Activation of FOXO1 induced nuclear exclusion but had no obvious effect on the whole-cell protein level of pancreatic and duodenal homeobox 1(PDX1).However, these effects were all attenuated by JNK inhibition.Furthermore, adenovirus-mediated overexpression of dominant-negative(DN)FOXO1 abolished whereas constitutively active(CA)-FOXO1 mimicked the effects of PGE(2) on GSIS in isolated mouse islets.In addition, we demonstrated that DN-JNK1 but not DN-JNK2 or CA-Akt abolished the PGE(2)-induced AP-1 luciferase reporter activity, whereas DN-JNK1 and CA-Akt but not DN-JNK2 reversed the effect of PGE(2) on FOXO1 transcriptional activity, and overexpression of DN-JNK1 rescued PGE(2)-impaired GSIS in mouse islets.Our results revealed that activation of the JNK is involved in PGE(2)induced beta-cell dysfunction.PGE(2)-mediated JNK1 activation, through dephosphorylation of Akt and FOXO1, leads to nuclear accumulation of FOXO1 and nucleocytoplasmic shuttling of PDX1, finally resulting in defective GSIS in pancreatic beta-cells.
