Antiinflammatory effects of the ETS factor ERG in endothelial cells are mediated through transcriptional repression of the interleukin-8 gene.
ERG (Ets-related gene) is an ETS transcription factor that has recently been shown to regulate a number of endothelial cell (EC)-restricted genes including VE-cadherin, von Willebrand factor, endoglin, and intercellular adhesion molecule-2. Our preliminary data demonstrate that unlike other ETS factors, ERG exhibits a highly EC-restricted pattern of expression in cultured primary cells and several adult mouse tissues including the heart, lung, and brain. In response to inflammatory stimuli, such as tumor necrosis factor-alpha, we observed a marked reduction of ERG expression in ECs. To further define the role of ERG in the regulation of normal EC function, we used RNA interference to knock down ERG. Microarray analysis of RNA derived from ERG small interfering RNA- or tumor necrosis factor-alpha-treated human umbilical vein (HUV)ECs revealed significant overlap (P<0.01) in the genes that are up- or downregulated. Of particular interest to us was a significant change in expression of interleukin (IL)-8 at both protein and RNA levels. Exposure of ECs to tumor necrosis factor-alpha is known to be associated with increased neutrophil attachment. We observed that knockdown of ERG in HUVECs is similarly associated with increased neutrophil attachment compared to control small interfering RNA-treated cells. This enhanced adhesion could be blocked with IL-8 neutralizing or IL-8 receptor blocking antibodies. ERG can inhibit the activity of the IL-8 promoter in a dose dependent manner. Direct binding of ERG to the IL-8 promoter in ECs was confirmed by chromatin immunoprecipitation. In summary, our findings support a role for ERG in promoting antiinflammatory effects in ECs through repression of inflammatory genes such as IL-8.
Division of Cardiology, Department of Medicine, and the Center for Vascular Biology Research, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA.
Lei
L
Yuan
Vesna
V
Nikolova-Krstevski
Yumei
Y
Zhan
Maiko
M
Kondo
Manoj
M
Bhasin
Laya
L
Varghese
Kiichiro
K
Yano
Chris V
CV
Carman
William C
WC
Aird
Peter
P
Oettgen
D000818:Animals; D002448:Cell Adhesion; D002478:Cells, Cultured; D018920:Coculture Techniques; D004195:Disease Models, Animal; D015536:Down-Regulation; D042783:Endothelial Cells / Q000187:drug effects / Q000378:metabolism*; D019446:Endotoxemia / Q000378:metabolism; D006801:Humans; D007249:Inflammation / Q000378:metabolism / Q000517:prevention & control*; D016209:Interleukin-8 / Q000235:genetics / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000494:pharmacology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009504:Neutrophils / Q000378:metabolism; D015513:Oncogene Proteins / Q000378:metabolism; D011401:Promoter Regions, Genetic; D034622:RNA Interference; D012333:RNA, Messenger / Q000378:metabolism; D034741:RNA, Small Interfering / Q000378:metabolism; D013997:Time Factors; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors; D014158:Transcription, Genetic; D000071230:Transcriptional Regulator ERG; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
C508606:CXCL8 protein, human; C072312:ERG protein, human; C531115:ERG protein, mouse; D016209:Interleukin-8; D008070:Lipopolysaccharides; D015513:Oncogene Proteins; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D015534:Trans-Activators; D014157:Transcription Factors; D000071230:Transcriptional Regulator ERG; D014409:Tumor Necrosis Factor-alpha; C440499:lipopolysaccharide, Escherichia coli O111 B4