Abstract
Copper (Cu), an essential micronutrient, plays a fundamental role in inflammation and angiogenesis; however, its precise mechanism remains undefined. Here we uncover a novel role of Cu transport protein Antioxidant-1 (Atox1), which is originally appreciated as a Cu chaperone and recently discovered as a Cu-dependent transcription factor, in inflammatory neovascularization. Atox1 expression is upregulated in patients and mice with critical limb ischemia. Atox1-deficient mice show impaired limb perfusion recovery with reduced arteriogenesis, angiogenesis, and recruitment of inflammatory cells. In vivo intravital microscopy, bone marrow reconstitution, and Atox1 gene transfer in Atox1(-/-) mice show that Atox1 in endothelial cells (ECs) is essential for neovascularization and recruitment of inflammatory cells which release VEGF and TNFα. Mechanistically, Atox1-depleted ECs demonstrate that Cu chaperone function of Atox1 mediated through Cu transporter ATP7A is required for VEGF-induced angiogenesis via activation of Cu enzyme lysyl oxidase. Moreover, Atox1 functions as a Cu-dependent transcription factor for NADPH oxidase organizer p47phox, thereby increasing ROS-NFκB-VCAM-1/ICAM-1 expression and monocyte adhesion in ECs inflamed with TNFα in an ATP7A-independent manner. These findings demonstrate a novel linkage between Atox1 and NADPH oxidase involved in inflammatory neovascularization and suggest Atox1 as a potential therapeutic target for treatment of ischemic disease.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
MeSH terms
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Adenosine Triphosphatases / genetics*
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Adenosine Triphosphatases / metabolism
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Animals
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Cation Transport Proteins / genetics*
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Cation Transport Proteins / metabolism
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Cell Adhesion Molecules / genetics
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Cell Adhesion Molecules / metabolism
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Cell Line
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Copper Transport Proteins
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Copper-Transporting ATPases
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Gene Expression Regulation
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Hindlimb
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Human Umbilical Vein Endothelial Cells / cytology
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Human Umbilical Vein Endothelial Cells / metabolism*
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Humans
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Ischemia / genetics*
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Ischemia / metabolism
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Ischemia / pathology
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Leg / blood supply
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Leg / pathology
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Metallochaperones / genetics*
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Metallochaperones / metabolism
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Mice
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Mice, Inbred C57BL
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Mice, Knockout
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Molecular Chaperones
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Monocytes / metabolism
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Monocytes / pathology
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NADPH Oxidases / genetics*
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NADPH Oxidases / metabolism
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Neovascularization, Pathologic / genetics*
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Neovascularization, Pathologic / metabolism
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Neovascularization, Pathologic / pathology
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Protein-Lysine 6-Oxidase / genetics*
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Protein-Lysine 6-Oxidase / metabolism
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Reactive Oxygen Species / metabolism
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Signal Transduction
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Tumor Necrosis Factor-alpha / genetics
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Tumor Necrosis Factor-alpha / metabolism
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Vascular Endothelial Growth Factor A / genetics
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Vascular Endothelial Growth Factor A / metabolism
Substances
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ATOX1 protein, human
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Cation Transport Proteins
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Cell Adhesion Molecules
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Copper Transport Proteins
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Metallochaperones
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Molecular Chaperones
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Reactive Oxygen Species
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Tumor Necrosis Factor-alpha
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VEGFA protein, human
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Vascular Endothelial Growth Factor A
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Protein-Lysine 6-Oxidase
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NADPH Oxidases
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neutrophil cytosolic factor 1
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Adenosine Triphosphatases
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ATP7A protein, human
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Copper-Transporting ATPases