Protein kinase C-mediated phosphorylation of p47 phox modulates platelet-derived growth factor-induced H2O2 generation and cell proliferation in human umbilical vein endothelial cells.
Substantial evidence indicate that growth factors such as platelet-derived growth factor (PDGF) exert their effect, at least in part, through reactive oxygen species (ROS) generated via NAD(P)H oxidase. In this work, the role of p47(phox), a key component of the phagocytic NAD(P)H oxidase in cell proliferation, was addressed. The authors show that diphenylene iodonium (DPI) and apocynin, but not N(G)-nitro-L-arginine methyl esterL-NAME, reduced PDGF-induced ROS generation and proliferation in human umbilical vein endothelial cells (HUVECs). Pharmacological inhibition of protein kinase C (PKC) as well as dominant-negative mutants of p47(phox) directed to PKC-dependent phosphorylation targets inhibited PDGF-stimulated ROS production and cell proliferation. Hydrogen peroxide restored PDGF-stimulated proliferation in cells that was inhibited by apocynin, DPI, or by the dominant-negative mutants. PDGF-induced proliferation was reduced in the HUVEC-derived cell line E.A.hy926 overexpressing catalase. On the contrary, cells overexpressing superoxide dismutase 1 exhibited increased proliferation. These results demonstrate that PKC-dependent phosphorylation of p47(phox) is essential for PDGF-stimulated ROS generation and proliferation in HUVECs. More relevant, H(2)O(2) is identified as the key molecule that signals proliferation in the systems studied.
Simon
F
F
Centro de Estudios Moleculares de la Célula e Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago, Chile.
Stutzin
A
A
D002374:Catalase / Q000378:metabolism; D002453:Cell Cycle; D002455:Cell Division / Q000502:physiology*; D004730:Endothelium, Vascular / Q000166:cytology* / Q000187:drug effects / Q000502:physiology*; D005260:Female; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism*; D007231:Infant, Newborn; D019255:NADPH Oxidases / Q000378:metabolism*; D010766:Phosphorylation; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology*; D011247:Pregnancy; D011493:Protein Kinase C / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000378:metabolism; D013482:Superoxide Dismutase / Q000378:metabolism; D014471:Umbilical Veins / Q000502:physiology*
D010982:Platelet-Derived Growth Factor; D017382:Reactive Oxygen Species; D006861:Hydrogen Peroxide; D002374:Catalase; D013482:Superoxide Dismutase; D019255:NADPH Oxidases; C060505:neutrophil cytosolic factor 1; D011493:Protein Kinase C