Copper Transport Protein Antioxidant-1 Promotes Inflammatory Neovascularization via Chaperone and Transcription Factor Function

Sci Rep. 2015 Oct 6:5:14780. doi: 10.1038/srep14780.

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

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Triphosphatases / genetics*
  • Adenosine Triphosphatases / metabolism
  • Animals
  • Cation Transport Proteins / genetics*
  • Cation Transport Proteins / metabolism
  • Cell Adhesion Molecules / genetics
  • Cell Adhesion Molecules / metabolism
  • Cell Line
  • Copper Transport Proteins
  • Copper-Transporting ATPases
  • Gene Expression Regulation
  • Hindlimb
  • Human Umbilical Vein Endothelial Cells / cytology
  • Human Umbilical Vein Endothelial Cells / metabolism*
  • Humans
  • Ischemia / genetics*
  • Ischemia / metabolism
  • Ischemia / pathology
  • Leg / blood supply
  • Leg / pathology
  • Metallochaperones / genetics*
  • Metallochaperones / metabolism
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Molecular Chaperones
  • Monocytes / metabolism
  • Monocytes / pathology
  • NADPH Oxidases / genetics*
  • NADPH Oxidases / metabolism
  • Neovascularization, Pathologic / genetics*
  • Neovascularization, Pathologic / metabolism
  • Neovascularization, Pathologic / pathology
  • Protein-Lysine 6-Oxidase / genetics*
  • Protein-Lysine 6-Oxidase / metabolism
  • Reactive Oxygen Species / metabolism
  • Signal Transduction
  • Tumor Necrosis Factor-alpha / genetics
  • Tumor Necrosis Factor-alpha / metabolism
  • Vascular Endothelial Growth Factor A / genetics
  • Vascular Endothelial Growth Factor A / metabolism

Substances

  • ATOX1 protein, human
  • Cation Transport Proteins
  • Cell Adhesion Molecules
  • Copper Transport Proteins
  • Metallochaperones
  • Molecular Chaperones
  • Reactive Oxygen Species
  • Tumor Necrosis Factor-alpha
  • VEGFA protein, human
  • Vascular Endothelial Growth Factor A
  • Protein-Lysine 6-Oxidase
  • NADPH Oxidases
  • neutrophil cytosolic factor 1
  • Adenosine Triphosphatases
  • ATP7A protein, human
  • Copper-Transporting ATPases