NOX2 and NOX4 Mediate Proliferative Response in Endothelial Cells

Abstract

Increased levels of reactive oxygen species (ROS) contribute to many cardiovascular diseases. In neutrophils, ROS are generated by a NADPH oxidase containing p22phox and NOX2. NADPH oxidases are also major sources of vascular ROS. Whereas an active NOX2-containing enzyme has been described in endothelial cells, the contribution of recently identified NOX homologues to endothelial ROS production and proliferation has been controversial. The authors, therefore, compared the role of NOX2 with NOX4 and NOX1 in endothelial EaHy926 and human microvascular endothelial cells. NOX2 and NOX4 were abundantly expressed, whereas NOX1 expression was less prominent. NOX2, NOX4, and NOX1 were simultaneously present in a single cell in a perinuclear compartment. NOX2 and NOX4 co-localized with the endoplasmic reticulum (ER) marker calreticulin. Additionally, NOX2 co-localized with F-actin at the plasma membrane. NOX2 and NOX4, which interacted with p22phox, as was shown by bimolecular fluorescent complementation, contributed equally to endothelial ROS production and proliferation, whereas NOX1 depletion did not alter ROS levels under basal conditions. These data show that endothelial cells simultaneously express NOX2, NOX4, and NOX1. NOX2 and NOX4, but not NOX1, equally contributed to ROS generation and proliferation under basal conditions, indicating that a complex relation between NOX homologues controls endothelial function.

NADPH Oxidase Is Internalized by Clathrin-coated Pits and Localizes to a Rab27A/B GTPase-regulated Secretory Compartment in Activated Macrophages

“…Dautry-Varsat and Benmerah) (25) and the CFP-gp91 phox fusion protein (26) were PCR-amplified with sticky primers for cloning into lentivector pLOX TW rtTA carrying a tetracycline-responsive promoter (27). The pHR EF gp91 phox lentivector, calcium phosphate transfection of HEK 293T producer cells, and lentivector production have been described (23).…”

“…In conclusion, although cyt b 558 is internalized through the CCP pathway, it is not accessible to internalized Tfn, which occupies early endosomes (sorting and recycling endosomes). 558 to the Cell Membrane-To explore exocytosis of the NADPH oxidase storage vesicles, we transduced Ra2 cells to conditionally express a CFP-gp91 phox fusion protein with CFP fused to the N terminus of human gp91 phox (26). CFP-gp91…”

Nox enzymes, ROS, and chronic disease: An example of antagonistic pleiotropy

“…Nox2 and Nox4 are both expressed in endothelium [41,42] where under some conditions they participate in cell proliferation [43] while Nox1, Nox4 [42,44] and Nox2 [45] are expressed in vascular smooth muscle cells. Nox1 in vascular smooth muscle participates in cell proliferation [46], while Nox4 in these cells participates in maintenance of the differentiated phenotype [47,48].…”

Reactive oxygen species and vascular biology: implications in human hypertension

“…[84][85][86] Nox4 is found in vascular cells, fibroblasts and osteoclasts and is abundantly expressed in the kidney. 87,88 In vascular smooth muscle cells, Nox4 and p22phox co-localize with vinculin in focal adhesions and has been implicated in cell migration, proliferation, tube formation, angiogenesis and cell differentiation. 87,88 Nox4 has also been found in the endoplasmic reticulum, mitochondria and nucleus of vascular cells.…”

“…87,88 In vascular smooth muscle cells, Nox4 and p22phox co-localize with vinculin in focal adhesions and has been implicated in cell migration, proliferation, tube formation, angiogenesis and cell differentiation. 87,88 Nox4 has also been found in the endoplasmic reticulum, mitochondria and nucleus of vascular cells. 89,90 Nox4 produces mainly H 2 O 2 , whereas Nox1 generates mostly O 2 À that is subsequently converted to H 2 O 2 .…”