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Nox4‐Type NADPH Oxidase Mediates the Angiogenic Response of Human Endothelial Cells in vitro
Author(s) -
Datla Srinivasa Raju,
Jiang Fan,
Dusting Greg J
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.5.a526-a
Subject(s) - nox4 , angiogenesis , nadph oxidase , matrigel , endothelial stem cell , microbiology and biotechnology , nox1 , small interfering rna , gene silencing , biology , chemistry , transfection , reactive oxygen species , cell culture , in vitro , cancer research , biochemistry , genetics , gene
Pro‐proliferative signaling within endothelial cells in postnatal angiogenic processes involves generation of reactive oxygen species. These act at least partly by facilitating VEGF signaling and promoting endothelial cell proliferation and migration. There is also some evidence that Nox2‐type NADPH oxidase has an important role in VEGF‐ and ischemia‐induced angiogenesis. Whether or not NADPH oxidase containing Nox4, another isoform of the catalytic component that is highly expressed in endothelial cells, has a role in angiogenesis has not been defined. In this study, we found that Nox4 expression in human microvascular endothelial cells (HMECs) was upregulated in proliferating cells as compared to quiescent cells. Nox4 gene silencing with small interfering RNA (siRNA) significantly reduced Nox4 protein expression and the superoxide production by 50 % (P < 0.01). It also reduced the angiogenic responses of HMECs in vitro, as determined by the tube formation assay on matrigel (mean tube length being 18 ± 1 vs 46 ± 4 μm in control, P < 0.001), and the wound healing assay on HMEC monolayers (35% reduction at 24 h, P < 0.01). In quiescent HMECs, VEGF also stimulated Nox4 expression. Nox4 siRNA markedly inhibited VEGF‐ and serum‐induced HMEC proliferation (25 and 19% reduction respectively, P < 0.01), and Nox4 siRNA also inhibited VEGF‐induced cell migration in boyden chambers (6.8 ± 0.6 vs 11.7 ± 7 cells per field at 6 h, P < 0.01). Our results clearly demonstrate that Nox4‐type NADPH oxidase has a critical role in mediating angiogenic responses in human cultured endothelial cells.