Direct Evidence for Endothelial Vascular Endothelial Growth Factor Receptor-1 Function in Nitric Oxide‚ÄìMediated Angiogenesis
Authors: Peter W Hewett
Jody J Haigh
Ping Wang
Takeshi Fujisawa
Debabrata Mukhopadhyay
Bahjat Al-Ani
Ferdinand le Noble
Asif Ahmed
Melissa Cudmore
Ling Wang
Shakil Ahmad
Journal: Circulation Research (2006)
Discipline: CLINICAL MEDICINE
Keywords: VEGF; angiogenesis; endothelial nitric oxide synthase; VEGFR-1; VEGFR-2
Affiliations: Department of Reproductive and Vascular Biology, Institute for Biomedical Research, The Medical School, University of Birmingham, Birmingham B15 2TT, UK. , From the Department of Reproductive and Vascular Biology (S.A., P.W.H., B.A.-A., M.C., T.F., A.A.), Institute for Biomedical Research, The Medical School, University of Birmingham, UK; Department of Biochemistry and Molecular Biology (P.W., L.W., D.M.), Mayo Clinic Foundation, Rochester, Minn; Department for Molecular Biomedical Research (J.J.H.), Flanders Interuniversity Institute of Biotechnology, Ghent University, Belgium; and Max Delbrueck Center for Molecular Medicine (F.l.N.), Berlin, Germany.

Abstract:  Vascular endothelial growth factor-A (VEGF) is critical for angiogenesis but fails to induce neovascularization in ischemic tissue lesions in mice lacking endothelial nitric oxide synthase (eNOS). VEGF receptor-2 (VEGFR-2) is critical for angiogenesis, although little is known about the precise role of endothelial VEGFR-1 and its downstream effectors in this process. Here we have used a chimeric receptor approach in which the extracellular domain of the epidermal growth factor receptor was substituted for that of VEGFR-1 (EGLT) or VEGFR-2 (EGDR) and transduced into primary cultures of human umbilical vein endothelial cells (HUVECs) using a retroviral system. Activation of HUVECs expressing EGLT or EGDR induced rapid phosphorylation of eNOS at Ser1177, release of NO, and formation of capillary networks, similar to VEGF. Activation of eNOS by VEGFR-1 was dependent on Tyr794 and was mediated via phosphatidylinositol 3-kinase, whereas VEGFR-2 Tyr951 was involved in eNOS activation via phospholipase Cgamma1. Consistent with these findings, the VEGFR-1-specific ligand placenta growth factor-1 activated phosphatidylinositol 3-kinase and VEGF-E, which is selective for VEGFR-2-activated phospholipase Cgamma1. Both VEGFR-1 and VEGFR-2 signal pathways converged on Akt, as dominant-negative Akt inhibited the NO release and in vitro tube formation induced following activation of EGLT and EGDR. The identification Tyr794 of VEGFR-1 as a key residue in this process provides direct evidence of endothelial VEGFR-1 in NO-driven in vitro angiogenesis. These studies provide new sites of modulation in VEGF-mediated vascular morphogenesis and highlight new therapeutic targets for management of vascular diseases. 

Retracted: No

PubPeer comments:
 Concern about Figure 12. Certain areas appear to be visible multiple times within the same photo. Could the authors please provide an explanation?  , 
 #1 Panel D has a fairly obvious pasted-in mitochondrion at 10 o clock, with jagged edges visible. Several other examples can be seen in this panel - for example at 2 and 6 o clock. There is a big one in panel A at 9 o clock , and - good grief, they re everywhere! , 
 #1 I would be more concerned about the mitochondria that seem to have been clumsily  helicoptered in to these panels. I have highlighted a few of the most obvious ones:  , 
 Retracted [21 April 2021] .  The editors of Toxicology Research are retracting the above article due to questions around the integrity of the data supporting the photomicrographs contained therein. The journal pursued the matter with the corresponding author following concerns raised by a reader, and sufficient doubts about the credibility of the study remain after an investigation lasting one year. The journal investigated this matter and has reached this decision in compliance with ethical guidelines endorsed by the Committee for Publication Ethics. ,