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Paradoxical activation of eNOS by NADPH Oxidase 5
Author(s) -
Malik Pulkit,
Fulton David
Publication year - 2008
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.22.1_supplement.758.29
Subject(s) - enos , nadph oxidase , nitric oxide , endothelium , vasodilation , superoxide , intracellular , chemistry , nitric oxide synthase , microbiology and biotechnology , reactive oxygen species , medicine , endocrinology , biology , biochemistry , enzyme
Activity of endothelial nitric oxide synthase (eNOS), a key determinant of cardiovascular is modulated by several factors, including reactive oxygen species (ROS). The goal of the current study was to assess the direct effects of intracellular ROS on endothelial function and the activity of eNOS. To achieve this, we utilized Nox5, a unique member of the NADPH oxidase family that can function as a single gene product. We transiently co‐expressed eNOS and Nox5 in COS‐7 cells and measured the amount of NO produced. Contrary to our original hypothesis, we found increased amounts of NO produced in cells expressing Nox5. In endothelial cells transduced with an adenovirus expressing Nox5, we observed dose‐dependent increases in NO production in cells expressing Nox5 using both NO‐specific chemiluminescence and a co‐culture cGMP bioassay. To establish the functional significance of this observation in blood vessels, the endothelium of mouse aorta was transduced with control or Nox5 adenoviruses. In precontracted blood vessels, acute exposure to SOD induced significant vascular relaxation in vessels exposed to Nox5 versus control and unmasked the ability of Nox5 to activate eNOS. To identify the underlying mechanism we next assessed whether Nox5 modifies eNOS phosphorylation, the intra‐versus extra‐cellular effects of Nox5 and the ability of Nox5 to activate a calcium‐independent eNOS mutant.