Hepatocyte growth factor induces a proangiogenic phenotype and mobilizes endothelial progenitor cells by activating Nox2.
Hepatocyte growth factor (HGF) by stimulating the receptor tyrosine kinase c-Met induces angiogenesis and tissue regeneration. HGF has been shown to antagonize the angiotensin II-induced senescence of endothelial progenitor cells (EPCs), which is mediated by NADPH oxidase-dependent reactive oxygen species (ROS) formation. As growth factors, however, usually require ROS for their signaling, we hypothesized that the proangiogenic effects of HGF require NADPH oxidases and focused on the homolog Nox2, which is most abundantly expressed in EPCs and endothelial cells. Indeed, HGF increased the H(2)O(2) formation in EPCs and human umbilical vein endothelial cells (HUVECs), and this effect was not observed in Nox2-deficient cells. HGF induced the mobilization of EPCs and vascular outgrowth from aortic explants in wild-type (WT) but not Nox2(y/-) mice. HGF also stimulated migration and tube formation in HUVECs, and antisense oligonucleotides against Nox2 prevented this effect. To identify the signal transduction underlying these effects, we focused on the kinases Jak2 and Jnk. In HUVECs, HGF increased the phosphorylation of these in a Nox2-dependent manner as demonstrated by antisense oligonucleotides. Also, the HGF-induced Jak2-dependent activation of a STAT3 reporter construct was attenuated after downregulation of Nox2. Accordingly, the HGF-stimulated tube formation of HUVEC was blocked by inhibitors of Jak2 and Jnk. In vivo treatment with the Jnk inhibitor SP600125 blocked the HGF-induced mobilization of EPCs. Ex vivo, SP600125 blocked HGF-induced migration and tube formation. We conclude that HGF-induced mobilization of EPCs and the proangiogenic effects of the growth factor require a Nox2-dependent ROS-mediated activation of Jak2 and Jnk.
Institut für Kardiovaskuläre Physiologie, Goethe-Universität, Frankfurt am Main, Germany. schroeder@zphys1.uni-frankfurt.de
Katrin
K
Schröder
Susanne
S
Schütz
Isabella
I
Schlöffel
Sina
S
Bätz
Ina
I
Takac
Norbert
N
Weissmann
U Ruth
UR
Michaelis
Masamichi
M
Koyanagi
Ralf P
RP
Brandes
D000818:Animals; D000873:Anthracenes / Q000378:metabolism; D001011:Aorta / Q000502:physiology; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000201:enzymology / Q000502:physiology*; D017228:Hepatocyte Growth Factor / Q000494:pharmacology*; D006801:Humans; D053614:Janus Kinase 2 / Q000378:metabolism; D048670:MAP Kinase Kinase 4 / Q000037:antagonists & inhibitors / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D000074662:NADPH Oxidase 2; D019255:NADPH Oxidases / Q000235:genetics / Q000378:metabolism*; D018919:Neovascularization, Physiologic; D010766:Phosphorylation; D017382:Reactive Oxygen Species / Q000378:metabolism; D050796:STAT3 Transcription Factor / Q000378:metabolism; D015398:Signal Transduction; D013234:Stem Cells / Q000187:drug effects* / Q000201:enzymology; D014471:Umbilical Veins / Q000166:cytology
D000873:Anthracenes; D008562:Membrane Glycoproteins; D017382:Reactive Oxygen Species; D050796:STAT3 Transcription Factor; C432165:pyrazolanthrone; D017228:Hepatocyte Growth Factor; C056558:CYBB protein, human; C488842:Cybb protein, mouse; D000074662:NADPH Oxidase 2; D019255:NADPH Oxidases; C507926:Jak2 protein, mouse; D053614:Janus Kinase 2; D048670:MAP Kinase Kinase 4