title: Transcriptional regulation of platelet-derived growth factor-B chain by thrombin in endothelial cells: involvement of Egr-1 and CREB-binding protein.
abstract: Thrombin and platelet-derived growth factor-B chain (PDGF-B) are key factors in the stimulation of atherosclerosis. The effect of thrombin on PDGF-B production has been characterized. However, the underlying mechanism is still far clear. Here, we investigate the transcription factors and regulators that are involved in PDGF-B production caused by thrombin in endothelial cells (ECs). Levels of PDGF were analyzed by real-time RT-PCR and ELISA, while levels of early growth response-1 (Egr-1) were analyzed by real-time RT-PCR and western blot. To evaluate the function of CBP and Egr-1 involved in regulation of PDGF-B, small interfering RNA (siRNA) were used to down-regulate their expression in mRNA and protein level. Interaction of Egr-1 and CBP was measured with immunoprecipitation and western blot. Thrombin induced an early and transient up-regulation of transcription factor early Egr-1, which was followed by a delayed increase of PDGF-B. siRNA against Egr-1-inhibited thrombin-induced PDGF-B production. Furthermore, thrombin could enhance the interaction of Egr-1 with its co-activator CREB-binding protein (CBP). CBP knockdown attenuated this interaction, and led to a reduction of PDGF-B expression induced by thrombin. Our results suggest that CBP might be one of the main interaction targets for Egr-1, and the transient activation of Egr-1 and recruitment of CBP are required for thrombin-induced PDGF-B in ECs.
authors.affiliation: Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan 430060, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Chen
authors.forename: Lin
authors.initials: L
authors.lastname: Xu
authors.forename: Sisi
authors.initials: S
authors.lastname: Chen
authors.forename: Jian
authors.initials: J
authors.lastname: Yang
authors.forename: Hong
authors.initials: H
authors.lastname: Jiang
mesh_terms: D000818:Animals; D001013:Aorta, Thoracic / Q000166:cytology; D050882:CREB-Binding Protein / Q000235:genetics / Q000378:metabolism*; D002478:Cells, Cultured; D051766:Early Growth Response Protein 1 / Q000235:genetics / Q000378:metabolism*; D042783:Endothelial Cells / Q000378:metabolism*; D005786:Gene Expression Regulation; D008297:Male; D011485:Protein Binding; D020574:Proto-Oncogene Proteins c-sis / Q000235:genetics* / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction; D013917:Thrombin / Q000502:physiology*; D014158:Transcription, Genetic; D015533:Transcriptional Activation
chemical_list: D051766:Early Growth Response Protein 1; C486110:Egr1 protein, rat; D020574:Proto-Oncogene Proteins c-sis; D050882:CREB-Binding Protein; C494365:Crebbp protein, rat; D013917:Thrombin