Upregulation of soluble vascular endothelial growth factor receptor type 1 by endogenous prostacyclin inhibitor coupling factor 6 in vascular endothelial cells: a role of acidosis-induced c-Src activation.
Vascular endothelial growth factor (VEGF) is a well-known promoter of angiogenesis, but its receptor VEGFR-1 and a soluble short form of VEGFR-1 (sFlt-1) play a negative role in the VEGF signal pathway by trapping VEGF. We recently showed that endogenous prostacyclin inhibitor coupling factor 6 (CF6) forces the clockwise rotation of F(1) motor of plasma membrane adenosine triphosphate synthase and induces intracellular acidosis and c-Src activation. We investigated the role of CF6 in regulation of sFlt-1, and its mechanism in human umbilical vein endothelial cells. The ratio of sFlt-1 to glyceraldehyde 3-phosphate dehydrogenase mRNA was increased at 24 h by 1.59+/-0.29-fold by 10(-7) M CF6 (P<0.05), concomitantly with the increases in intercellular adhesion molecule-1 and lectin-like oxidized low-density lipoprotein receptor-1 and no change in VEGF-A. When the dose of CF6 was increased to 10(-6) M, no further increase in sFlt-1 mRNA was observed. The release of sFlt-1 protein was increased by 1.72+/-0.24-fold (P<0.05) at 48 h after exposure to CF6 at 10(-7) M, and it was blocked by pretreatment with anti-CF6 antibody. The immunoreactive bands for sFlt-1 and VEGFR-1 were both increased by CF6 to similar degrees. Pretreatment with PP1, an inhibitor of c-Src, and 10(-5) Mefrapeptin, an inhibitor of F(1) motor, inhibited CF6-induced increases in expression and release of sFlt-1 (P<0.05). In mice overexpressing CF6, the plasma level of sFlt-1 was increased by 1.36+/-0.29-fold compared with that in wild-type mice (P<0.05). These indicate that CF6 might increase the expression and release of sFlt-1 in the vessels through acidosis-induced c-Src activation.
Echizen
Takashi
T
Department of Cardiology, Hirosaki University Graduate School of Medicine, Hirosaki, Japan.
Osanai
Tomohiro
T
Ashitate
Toshihiro
T
Yokoyama
Hiroaki
H
Shibutani
Shuji
S
Tanaka
Makoto
M
Tomita
Hirofumi
H
Magota
Koji
K
Okumura
Ken
K
D000138:Acidosis / Q000503:physiopathology*; D000818:Animals; D001711:Biotransformation / Q000187:drug effects; D015153:Blotting, Western; D002460:Cell Line; D042783:Endothelial Cells / Q000187:drug effects*; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects*; D015870:Gene Expression / Q000187:drug effects; D005822:Genetic Vectors; D006801:Humans; D000860:Hypoxia / Q000378:metabolism; D051379:Mice; D008822:Mice, Transgenic; D025261:Mitochondrial Proton-Translocating ATPases / Q000494:pharmacology*; D010086:Oxidative Phosphorylation Coupling Factors / Q000494:pharmacology*; D016392:Proto-Oncogene Proteins pp60(c-src) / Q000502:physiology*; D012333:RNA, Messenger / Q000032:analysis / Q000096:biosynthesis / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015854:Up-Regulation / Q000502:physiology; D040281:Vascular Endothelial Growth Factor Receptor-1 / Q000096:biosynthesis* / Q000187:drug effects / Q000235:genetics
D010086:Oxidative Phosphorylation Coupling Factors; D012333:RNA, Messenger; C501162:FLT1 protein, human; D040281:Vascular Endothelial Growth Factor Receptor-1; D016392:Proto-Oncogene Proteins pp60(c-src); C000628217:F(6) ATPase; D025261:Mitochondrial Proton-Translocating ATPases