FGF-dependent regulation of VEGF receptor 2 expression in mice
Masahiro Murakami, … , Brian L. Black, Michael Simons
Masahiro Murakami, … , Brian L. Black, Michael Simons
Published June 1, 2011
Citation Information: J Clin Invest. 2011;121(7):2668-2678. https://doi.org/10.1172/JCI44762.
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Research Article Vascular biology Article has an altmetric score of 6

FGF-dependent regulation of VEGF receptor 2 expression in mice

Abstract

Numerous studies have suggested a link between the angiogenic FGF and VEGF signaling pathways; however, the nature of this link has not been established. To evaluate this relationship, we investigated VEGF signaling in ECs with disrupted FGF signaling in vitro and in vivo. ECs lacking FGF signaling became unresponsive to VEGF, caused by downregulation of VEGF receptor 2 (VEGFR2) expression after reduced Vegfr2 enhancer activation. FGF mediated VEGFR2 expression via activation of Erk1/2. Transcriptional analysis revealed that Ets transcription factors controlled VEGFR2 expression in an FGF- and Erk1/2-dependent manner. Mice with defective FGF signaling exhibited loss of vascular integrity and reduced vascular morphogenesis. Thus, basal FGF stimulation of the endothelium is required for maintenance of VEGFR2 expression and the ability to respond to VEGF stimulation and accounts for the hierarchic control of vascular formation by FGFs and VEGF.

Authors

Masahiro Murakami, Loc T. Nguyen, Kunihiko Hatanaka, William Schachterle, Pei-Yu Chen, Zhen W. Zhuang, Brian L. Black, Michael Simons

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Figure 1

FGF regulation of VEGF signaling and VEGFR2 expression.

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FGF regulation of VEGF signaling and VEGFR2 expression. (A) Western blot...
(A) Western blot of total cell lysates of BAECs transduced with Ad-GFP or Ad-FGFR1DN and stimulated with FGF1 (50 ng/ml) or VEGF-A (80 ng/ml) for 5 minutes. Cont, control; p-, phosphorylated; t-, total. (B) Quantitative analysis of cellular cGMP levels (n = 3). (C) Quantitative RT-PCR analysis of total RNA isolated from BAECs. Vegfr2 mRNA levels were measured with real-time PCR and normalized to Gapdh expression. Values denote abundance relative to that of untreated BAECs (assigned as 1). (D) Western blotting of total cell lysates isolated from BAECs treated with U0126 at different concentrations for 6 hours in normal growth medium. (E) Quantitative analysis of VEGFR2 levels. (F) BAECs were first transduced with Ad-Null or Ad-FGFR1DN, then the next day with Ad-ME or Ad–ME-LA. Quantitative PCR analysis of VEGFR2 expression was performed (n = 3). (G) Western blotting of total cell lysates showed increased VEGFR2 levels in Ad-FGFR1DN–transduced cells after Ad–ME-LA treatment. ME-LA and FGFR1DN (gray and black arrows, respectively) were detected with an HA antibody. *P < 0.05, **P < 0.01 versus respective control.