In vivo evidence of angiogenesis induced by transcription factor Ets-1: Ets-1 is located upstream of angiogenesis cascade.
BACKGROUND
A transcription factor, ets-1, regulates the transcription of metalloproteinase genes, the activity of which is necessary for matrix degradation and the migration of endothelial cells. However, no study has demonstrated that ets-1 itself has an angiogenic action in vivo. Thus, we examined (1) the effects of overexpression of the ets-1 gene on angiogenesis in a rat hindlimb ischemia model, and (2) how ets-1 induced angiogenesis.


RESULTS
In this study, we used the HVJ-liposome method, which is highly effective for transfection, to transfect the human ets-1 gene. At 4 weeks after transfection, the capillary density and blood flow were significantly increased in a hindlimb transfected with the human ets-1 gene compared with control. These data clearly demonstrated that ets-1 has the ability to stimulate angiogenesis in vivo. To elucidate the molecular mechanisms by which ets-1 induced angiogenesis, we focused especially on the expression of hepatocyte growth factor (HGF) and vascular endothelial growth factor (VEGF), potent angiogenic growth factors, because the promoter regions of both genes contain ets binding sites. Interestingly, overexpression of ets-1 upregulated both tissue HGF and VEGF concentrations in rat hindlimb. More importantly, administration of neutralizing antibody against HGF and VEGF attenuated the increase in blood flow and BrdU-positive cells induced by ets-1. Upregulation of HGF and VEGF by ets-1 was also confirmed by in vitro experiments using human vascular smooth muscle cells.


CONCLUSIONS
The present study demonstrated that ets-1 regulated angiogenesis through the induction of angiogenic growth factors (VEGF and HGF). Overexpression of ets may provide a new therapeutic strategy to treat peripheral arterial disease.
Hashiya
Naotaka
N
Division of Clinical Gene Therapy, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan.
Jo
Nobuo
N
Aoki
Motokuni
M
Matsumoto
Kunio
K
Nakamura
Toshikazu
T
Sato
Yasufumi
Y
Ogata
Nahoko
N
Ogihara
Toshio
T
Kaneda
Yasufumi
Y
Morishita
Ryuichi
R
D000818:Animals; D002465:Cell Movement; D002478:Cells, Cultured / Q000378:metabolism; D005786:Gene Expression Regulation; D015316:Genetic Therapy; D017228:Hepatocyte Growth Factor / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000235:genetics; D006614:Hindlimb / Q000098:blood supply; D006801:Humans; D007511:Ischemia / Q000235:genetics* / Q000503:physiopathology / Q000628:therapy; D017078:Laser-Doppler Flowmetry; D008081:Liposomes; D009131:Muscle, Smooth, Vascular / Q000166:cytology; D032389:Myocytes, Smooth Muscle / Q000378:metabolism; D018919:Neovascularization, Physiologic / Q000235:genetics*; D050784:Proto-Oncogene Protein c-ets-1; D011518:Proto-Oncogene Proteins / Q000502:physiology*; D050783:Proto-Oncogene Proteins c-ets; D051381:Rats; D017207:Rats, Sprague-Dawley; D011993:Recombinant Fusion Proteins / Q000502:physiology; D014157:Transcription Factors / Q000502:physiology*; D014162:Transfection; D042461:Vascular Endothelial Growth Factor A / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000235:genetics
C494041:ETS1 protein, human; C494043:Ets1 protein, rat; D008081:Liposomes; D050784:Proto-Oncogene Protein c-ets-1; D011518:Proto-Oncogene Proteins; D050783:Proto-Oncogene Proteins c-ets; D011993:Recombinant Fusion Proteins; D014157:Transcription Factors; D042461:Vascular Endothelial Growth Factor A; D017228:Hepatocyte Growth Factor