TY - JOUR
T1 - Exendin-4 differentiation of a human pancreatic duct cell line into endocrine cells
T2 - Involvement of PDX-1 and HNF3β transcription factors
AU - Zhou, Jie
AU - Pineyro, Marco A.
AU - Wang, Xiaolin
AU - Doyle, Maire E.
AU - Egan, Josephine M.
PY - 2002
Y1 - 2002
N2 - Exendin-4 (EX-4), a long acting agonist of GLP-1, induces an endocrine phenotype in Capan-1 cells. Under culture conditions which include serum, ∼10% of the cells contain insulin and glucagon. When exposed to EX-4 (0.1 Nm, up to 5 days), the number of cells containing insulin and glucagon increased to ∼40%. Western blot analysis detected a progressive increase in protein levels of glucokinase and GLUT2 over 3 days of EX-4 treatment. We explored the sequence of activation of certain transcription factors known to be essential for the beta cell phenotype: PDX-1, Beta2/NeuroD, and hepatocyte nuclear factor 3β (HNF3 β). Double immunostaining showed that PDX-1 coexisted with insulin and glucagon in EX-4-treated cells. Treatment caused an increase in PDX-1 protein levels by 24 h and induced its nuclear translocation. Beta2/NeuroD protein levels also increased progressively over 24 h. HNF3β protein level increased twofold as early as 6 h after EX-4 treatment. EMSA results indicated that EX-4 caused a 1 2-fold increase in HNF3β binding to PDX-1 promoter area II. Beta2/NeuroD protein levels progressively increased after 24 h treatment. Differentiation to insulin-producing cells was also seen when Capan-1 cells were transfected with pdx-1, with 80% of these cells expressing insulin 3 days after transfection. PDX-1 antisense totally inhibited such conversion. During the differentiation of duct cells to endocrine cells, CAMP levels (EX-4 is a ligand for the GLP-1, G-protein coupled receptor) and MAP kinase activity increased. Our results indicate that EX-4 activates adenylyl cyclase and MAP kinase which, in turn, may lead to activation of transcription factors necessary for an endocrine phenotype.
AB - Exendin-4 (EX-4), a long acting agonist of GLP-1, induces an endocrine phenotype in Capan-1 cells. Under culture conditions which include serum, ∼10% of the cells contain insulin and glucagon. When exposed to EX-4 (0.1 Nm, up to 5 days), the number of cells containing insulin and glucagon increased to ∼40%. Western blot analysis detected a progressive increase in protein levels of glucokinase and GLUT2 over 3 days of EX-4 treatment. We explored the sequence of activation of certain transcription factors known to be essential for the beta cell phenotype: PDX-1, Beta2/NeuroD, and hepatocyte nuclear factor 3β (HNF3 β). Double immunostaining showed that PDX-1 coexisted with insulin and glucagon in EX-4-treated cells. Treatment caused an increase in PDX-1 protein levels by 24 h and induced its nuclear translocation. Beta2/NeuroD protein levels also increased progressively over 24 h. HNF3β protein level increased twofold as early as 6 h after EX-4 treatment. EMSA results indicated that EX-4 caused a 1 2-fold increase in HNF3β binding to PDX-1 promoter area II. Beta2/NeuroD protein levels progressively increased after 24 h treatment. Differentiation to insulin-producing cells was also seen when Capan-1 cells were transfected with pdx-1, with 80% of these cells expressing insulin 3 days after transfection. PDX-1 antisense totally inhibited such conversion. During the differentiation of duct cells to endocrine cells, CAMP levels (EX-4 is a ligand for the GLP-1, G-protein coupled receptor) and MAP kinase activity increased. Our results indicate that EX-4 activates adenylyl cyclase and MAP kinase which, in turn, may lead to activation of transcription factors necessary for an endocrine phenotype.
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U2 - 10.1002/jcp.10143
DO - 10.1002/jcp.10143
M3 - Article
C2 - 12124776
AN - SCOPUS:0036326210
SN - 0021-9541
VL - 192
SP - 304
EP - 314
JO - Journal of Cellular Physiology
JF - Journal of Cellular Physiology
IS - 3
ER -