The PKA/CREB pathway is closely involved in VEGF expression in mouse macrophages.
Cyclic AMP-responsive element binding protein (CREB) is known to be associated with angiogenesis. In the present study we investigated the possible role of CREB in the expression of vascular endothelial growth factor (VEGF) by mouse macrophages. Over-expression of CREB increased VEGF secretion by cells of the RAW264.7 mouse macrophage cell line. It also increased the promoter activity of a mouse reporter driven by the VEGF promoter, while a dominant negative CREB (DN-CREB) abrogated the activity, suggesting that CREB mediates VEGF transcription. Forskolin, an adenylyl cyclase activator, stimulated VEGF transcription, and the PKA inhibitor H89 abolished this effect. IFN-gamma, a potent cytokine, stimulated VEGF expression only in part through the PKA-CREB pathway. These results indicate that PKA phosphorylates CREB and so induces VEGF gene expression. An analysis of mutant promoters revealed that one of the putative CREB responsive elements (CREs), at 399 approximately 388 in the promoter, is critical for CREB-mediated VEGF promoter activity, and the significance of this CRE was confirmed by chromatin immunoprecipitation assays.
Jeon
Seong-Hyun
SH
Department of Molecular Bioscience, School of Bioscience and Biotechnology, Kangwon National University, Chunchon 200-701 Korea.
Chae
Byung-Chul
BC
Kim
Hyun-A
HA
Seo
Goo-Young
GY
Seo
Dong-Wan
DW
Chun
Gie-Taek
GT
Yie
Se-Won
SW
Eom
Seok-Hyun
SH
Kim
Pyeung-Hyeun
PH
D000818:Animals; D047369:Chromatin Immunoprecipitation; D005576:Colforsin / Q000494:pharmacology; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism*; D054746:Cyclic AMP-Dependent Protein Kinase Type II; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000187:drug effects; D007371:Interferon-gamma / Q000494:pharmacology; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism*; D051379:Mice; D008807:Mice, Inbred BALB C; D011485:Protein Binding / Q000187:drug effects; D020218:Response Elements / Q000187:drug effects / Q000235:genetics; D014158:Transcription, Genetic / Q000187:drug effects; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics* / Q000378:metabolism*
D017362:Cyclic AMP Response Element-Binding Protein; D042461:Vascular Endothelial Growth Factor A; D005576:Colforsin; D007371:Interferon-gamma; D054746:Cyclic AMP-Dependent Protein Kinase Type II; D017868:Cyclic AMP-Dependent Protein Kinases