Nitric oxide prevents aortic neointimal hyperplasia by controlling macrophage polarization

Arterioscler Thromb Vasc Biol. 2014 Aug;34(8):1739-46. doi: 10.1161/ATVBAHA.114.303866. Epub 2014 Jun 12.


Objective: Nitric oxide synthase 3 (NOS3) prevents neointima hyperplasia by still unknown mechanisms. To demonstrate the significance of endothelial nitric oxide in the polarization of infiltrated macrophages through the expression of matrix metalloproteinase (MMP)-13 in neointima formation.

Approach and results: After aortic endothelial denudation, NOS3 null mice show elevated neointima formation, detecting increased mobilization of LSK (lineage-negative [Lin]-stem-cell antigen 1 [SCA1]+KIT+) progenitor cells, and high ratios of M1 (proinflammatory) to M2 (resolving) macrophages, accompanied by high expression of interleukin-5, interleukin-6, MCP-1 (monocyte chemoattractant protein), VEGF (vascular endothelial growth factor), GM-CSF (granulocyte-macrophage colony stimulating factor), interleukin-1β, and interferon-γ. In conditional c-Myc knockout mice, in which M2 polarization is defective, denuded aortas showed extensive wall thickening as well. Conditioned medium from NOS3-deficient endothelium induced extensive repolarization of M2 macrophages to an M1 phenotype, and vascular smooth muscle cells proliferated and migrated faster in conditioned medium from M1 macrophages. Among the different proteins participating in cell migration, MMP-13 was preferentially expressed by M1 macrophages. M1-mediated vascular smooth muscle cell migration was inhibited when macrophages were isolated from MMP-13-deficient mice, whereas exogenous administration of MMP-13 to vascular smooth muscle cell fully restored migration. Excess vessel wall thickening in mice lacking NOS3 was partially reversed by simultaneous deletion of MMP-13, indicating that NOS3 prevents neointimal hyperplasia by preventing MMP-13 activity. An excess of M1-polarized macrophages that coexpress MMP-13 was also detected in human carotid samples from endarterectomized patients.

Conclusions: These findings indicate that at least M1 macrophage-mediated expression of MMP-13 in NOS3 null mice induces neointima formation after vascular injury, suggesting that MMP-13 may represent a new promising target in vascular disease.

Keywords: angioplasty; entothelial nitric oxide synthase 3; macrophage; matrix metalloproteinase-13; neointima.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Aged, 80 and over
  • Animals
  • Aorta / metabolism
  • Aorta / pathology
  • Aortic Diseases / enzymology
  • Aortic Diseases / genetics
  • Aortic Diseases / metabolism*
  • Aortic Diseases / pathology
  • Biomarkers / metabolism
  • Case-Control Studies
  • Cell Differentiation
  • Cell Lineage
  • Cell Movement
  • Cell Proliferation
  • Cells, Cultured
  • Disease Models, Animal
  • Female
  • Humans
  • Hyperplasia
  • Inflammation Mediators / metabolism
  • Macrophages / enzymology
  • Macrophages / metabolism*
  • Macrophages / pathology
  • Male
  • Matrix Metalloproteinase 13 / deficiency
  • Matrix Metalloproteinase 13 / genetics
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Middle Aged
  • Muscle, Smooth, Vascular / enzymology
  • Muscle, Smooth, Vascular / metabolism*
  • Muscle, Smooth, Vascular / pathology
  • Myocytes, Smooth Muscle / enzymology
  • Myocytes, Smooth Muscle / metabolism*
  • Myocytes, Smooth Muscle / pathology
  • Neointima*
  • Nitric Oxide / metabolism*
  • Nitric Oxide Synthase Type III / deficiency
  • Nitric Oxide Synthase Type III / genetics
  • Phenotype
  • Proto-Oncogene Proteins c-myc / deficiency
  • Proto-Oncogene Proteins c-myc / genetics
  • Time Factors


  • Biomarkers
  • Inflammation Mediators
  • Myc protein, mouse
  • Proto-Oncogene Proteins c-myc
  • Nitric Oxide
  • Nitric Oxide Synthase Type III
  • Nos3 protein, mouse
  • Matrix Metalloproteinase 13
  • Mmp13 protein, mouse