The transcriptional factor PREB mediates MCP-1 transcription induced by cytokines in human vascular endothelial cells.
OBJECTIVE
The prolactin regulatory element binding (PREB) protein is a transcriptional factor that regulates prolactin promoter activity in rat anterior pituitary. It is expressed not only in the anterior pituitary but also in the cardiovascular system, including in human umbilical vascular endothelial cells (HUVECs). Monocyte chemoattractant protein-1 (MCP-1) is a major chemotactic factor for monocytes and a key factor initiating the inflammatory process of atherogenesis. MCP-1 is expressed in HUVECs in response to several different stimuli, including interleukin (IL)-1beta and tumor necrosis factor (TNF)-alpha.


RESULTS
MCP-1 expression was regulated by IL-1beta and TNF-alpha and cytokine-induced PREB expression. Conversely, over-expression of PREB using a PREB-expressing adenovirus increased MCP-1 expression in HUVECs. In addition, PREB induced the expression of the luciferase reporter protein under the MCP-1 promoter control. EMSA showed that the transcriptional effect of PREB was mediated by its binding to the PREB-responsive cis-element of the MCP-1 promoter. Finally, we used siRNA to inhibit PREB expression in HUVECs and demonstrated that knockdown of PREB expression attenuated the effects of IL-1beta and TNF-alpha on MCP-1 expression.


CONCLUSIONS
In summary, our findings show that PREB can function as a transcriptional regulator of the MCP-1 promoter in response to cytokines.
Murao
Koji
K
Division of Endocrinology and Metabolism, Department of Internal Medicine, Faculty of Medicine, Kagawa University, 1750-1 Ikenobe Miki-CHO, Kita-gun, Kagawa 761-0793, Japan. mkoji@med.kagawa-u.ac.jp
Imachi
Hitomi
H
Yu
Xiao
X
Muraoka
Tomie
T
Hosami
Naohisa
N
Dobashi
Hiroaki
H
Ishida
Toshihiko
T
D000818:Animals; D001665:Binding Sites; D002478:Cells, Cultured; D018932:Chemokine CCL2 / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D024202:Electrophoretic Mobility Shift Assay; D042783:Endothelial Cells / Q000276:immunology / Q000378:metabolism*; D020662:Guanine Nucleotide Exchange Factors / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D053583:Interleukin-1beta / Q000378:metabolism*; D009154:Mutation; D011401:Promoter Regions, Genetic; D034622:RNA Interference; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D015533:Transcriptional Activation; D014162:Transfection; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*
C111835:CCL2 protein, human; D018932:Chemokine CCL2; D004268:DNA-Binding Proteins; D020662:Guanine Nucleotide Exchange Factors; D053583:Interleukin-1beta; C118971:PREB protein, human; C485592:Preb protein, rat; D012333:RNA, Messenger; D014157:Transcription Factors; D014409:Tumor Necrosis Factor-alpha