NADPH oxidase 4 mediates reactive oxygen species induction of CD146 dimerization in VEGF signal transduction.
CD146 dimerization plays an important role in tumor-induced angiogenesis. Stimulation of target cells with vascular endothelial growth factor (VEGF), a major angiogenic factor produced by tumor cells, elicits a burst of reactive oxygen species (ROS) that enhances angiogenesis. However, the molecular mechanism coupling CD146 dimerization with the VEGF-related oxidant-generating apparatus has not been elucidated. Here, we show that CD146 dimerization is induced by VEGF and is significantly diminished by pretreatment with diphenylene iodonium, an inhibitor of NADPH oxidase, suggesting a potential role for NADPH oxidase (NOX) in VEGF-induced CD146 dimerization. Importantly, we found that overexpression of NADPH oxidase 4 (NOX4), which is the predominant NOX expressed in endothelial cells, significantly enhances VEGF-induced ROS generation and CD146 dimerization. By contrast, these VEGF effects were dramatically attenuated after transfection with siRNA to reduce NOX4 expression. Furthermore, expression of Rac1 N17, a dominant negative mutant of Rac1, a member of the Rho family of small GTPases, suppressed VEGF-induced ROS generation and CD146 dimerization. These studies show for the first time that VEGF alteration of CD146 dimerization is mediated via a NOX4-dependent pathway and provide novel insight into the significant role of NOX in redox regulation of the dimerization of cell adhesion molecules.
Zhuang
Jie
J
National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.
Jiang
Tianxia
T
Lu
Di
D
Luo
Yongting
Y
Zheng
Chaogu
C
Feng
Jing
J
Yang
Dongling
D
Chen
Chang
C
Yan
Xiyun
X
D051929:CD146 Antigen / Q000235:genetics / Q000378:metabolism; D002448:Cell Adhesion; D002460:Cell Line; D042783:Endothelial Cells / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D006801:Humans; D050505:Mutant Proteins / Q000096:biosynthesis / Q000235:genetics; D009861:Onium Compounds / Q000494:pharmacology; D010084:Oxidation-Reduction; D055503:Protein Multimerization / Q000187:drug effects* / Q000235:genetics; D034741:RNA, Small Interfering / Q000235:genetics; D017382:Reactive Oxygen Species / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism*; D020830:rac1 GTP-Binding Protein / Q000096:biosynthesis / Q000235:genetics
D051929:CD146 Antigen; C497902:MCAM protein, human; D050505:Mutant Proteins; D009861:Onium Compounds; D034741:RNA, Small Interfering; D017382:Reactive Oxygen Species; D042461:Vascular Endothelial Growth Factor A; C007517:diphenyleneiodonium; D020830:rac1 GTP-Binding Protein