OBJECTIVE: Cytochrome P450 (CYP) epoxygenase-derived epoxyeicosatrienoic acids (EETs) are known to stimulate angiogenesis, but the mechanisms involved are incompletely understood. Because EphB4 is involved in vascular development, the aim of this study was to investigate whether, and to what extent, EphB4 is part of the signaling cascade that results in CYP2C9-mediated angiogenesis. METHODS AND RESULTS: CYP2C9 overexpression as well as stimulation with 11,12-EET (up to 48 hours) time-dependently increased EphB4 expression in endothelial cells. This effect and the activation of the EphB4 promoter were mediated by the phosphatidylinositol-3-kinase (P13-K)/Akt pathway and sensitive to the P13-K inhibitor LY 294002 as well as to simultaneous transfection with dominant-negative Akt. 11,12-EET treatment also increased EphB4 expression in isolated mouse mesenteric arteries as well as in the vessels that developed in 11,12-EET-impregnated Matrigel plugs. Moreover, the CYP2C9-stimulated formation of capillary-like structures in a modified spheroid assay was markedly attenuated by EphB4 downregulation (antisense oligonucleotides). Using a parallel approach in vivo, the inclusion of siRNA directed against EphB4 in EET-impregnated Matrigel plugs prevented endothelial cell invasion and vascularization. CONCLUSIONS: Our data indicate that EphB4 is a critical component of the CYP2C9- and 11,12-EET-activated signaling cascade that promotes angiogenesis in vitro as well as in vivo.
OBJECTIVE:Cytochrome P450 (CYP) epoxygenase-derived epoxyeicosatrienoic acids (EETs) are known to stimulate angiogenesis, but the mechanisms involved are incompletely understood. Because EphB4 is involved in vascular development, the aim of this study was to investigate whether, and to what extent, EphB4 is part of the signaling cascade that results in CYP2C9-mediated angiogenesis. METHODS AND RESULTS: CYP2C9 overexpression as well as stimulation with 11,12-EET (up to 48 hours) time-dependently increased EphB4 expression in endothelial cells. This effect and the activation of the EphB4 promoter were mediated by the phosphatidylinositol-3-kinase (P13-K)/Akt pathway and sensitive to the P13-K inhibitor LY 294002 as well as to simultaneous transfection with dominant-negative Akt. 11,12-EET treatment also increased EphB4 expression in isolated mouse mesenteric arteries as well as in the vessels that developed in 11,12-EET-impregnated Matrigel plugs. Moreover, the CYP2C9-stimulated formation of capillary-like structures in a modified spheroid assay was markedly attenuated by EphB4 downregulation (antisense oligonucleotides). Using a parallel approach in vivo, the inclusion of siRNA directed against EphB4 in EET-impregnated Matrigel plugs prevented endothelial cell invasion and vascularization. CONCLUSIONS: Our data indicate that EphB4 is a critical component of the CYP2C9- and 11,12-EET-activated signaling cascade that promotes angiogenesis in vitro as well as in vivo.
Authors: Timo Frömel; Benno Jungblut; Jiong Hu; Caroline Trouvain; Eduardo Barbosa-Sicard; Rüdiger Popp; Stefan Liebner; Stefanie Dimmeler; Bruce D Hammock; Ingrid Fleming Journal: Proc Natl Acad Sci U S A Date: 2012-06-04 Impact factor: 11.205
Authors: Anna Lena Sander; Heike Jakob; Katharina Sommer; Christian Sadler; Ingrid Fleming; Ingo Marzi; Johannes Frank Journal: Langenbecks Arch Surg Date: 2011-09-02 Impact factor: 3.445
Authors: Jiong Hu; Alexandra Geyer; Sarah Dziumbla; Khader Awwad; Darryl C Zeldin; Wolf-Hagen Schunck; Rüdiger Popp; Timo Frömel; Ingrid Fleming Journal: Prostaglandins Other Lipid Mediat Date: 2017-04-23 Impact factor: 3.072
Authors: Anke C Webler; U Ruth Michaelis; Rüdiger Popp; Eduardo Barbosa-Sicard; Andiappan Murugan; John R Falck; Beate Fisslthaler; Ingrid Fleming Journal: Am J Physiol Cell Physiol Date: 2008-09-11 Impact factor: 4.249
Authors: Benjamin Keserü; Eduardo Barbosa-Sicard; Ralph T Schermuly; Hiromasa Tanaka; Bruce D Hammock; Norbert Weissmann; Beate Fisslthaler; Ingrid Fleming Journal: Cardiovasc Res Date: 2010-01-01 Impact factor: 10.787