Oxidative stress activates protein tyrosine kinase and matrix metalloproteinases leading to blood-brain barrier dysfunction

J Neurochem. 2007 Apr;101(2):566-76. doi: 10.1111/j.1471-4159.2006.04393.x. Epub 2007 Jan 23.


The blood-brain barrier (BBB) formed by brain microvascular endothelial cells (BMVEC) regulates the passage of molecules and leukocytes in and out of the brain. Oxidative stress is a major underlying cause of neurodegenerative and neuroinflammatory disorders and BBB injury associated with them. Using human BMVEC grown on porous membranes covered with basement membrane (BM) matrix (BBB models), we demonstrated that reactive oxygen species (ROS) augmented permeability and monocyte migration across BBB. ROS activated matrix metalloproteinases (MMP-1, -2, and -9) and decreased tissue inhibitors of MMPs (TIMP-1 and -2) in a protein tyrosine kinase (PTK)-dependent manner. Increase in MMPs and PTK activities paralleled degradation of BM protein and enhanced tyrosine phosphorylation of tight junction (TJ) protein. These effects and enhanced permeability/monocyte migration were prevented by inhibitors of MMPs, PTKs, or antioxidant suggesting that oxidative stress caused BBB injury via degradation of BM protein by activated MMPs and by PTK-mediated TJ protein phosphorylation. These findings point to new therapeutic interventions ameliorating BBB dysfunction in neurological disorders such as stroke or neuroinflammation.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Basement Membrane / enzymology
  • Basement Membrane / metabolism
  • Basement Membrane / pathology
  • Blood-Brain Barrier / enzymology*
  • Blood-Brain Barrier / physiopathology
  • Cells, Cultured
  • Cerebral Arteries / enzymology*
  • Cerebral Arteries / physiopathology
  • Chemotaxis, Leukocyte / drug effects
  • Chemotaxis, Leukocyte / physiology
  • Encephalitis / enzymology
  • Encephalitis / physiopathology
  • Endothelial Cells / cytology
  • Endothelial Cells / enzymology*
  • Enzyme Activation / physiology
  • Enzyme Inhibitors / pharmacology
  • Humans
  • Matrix Metalloproteinases / metabolism*
  • Neurodegenerative Diseases / enzymology
  • Neurodegenerative Diseases / physiopathology
  • Oxidative Stress / physiology*
  • Protein-Tyrosine Kinases / metabolism*
  • Reactive Oxygen Species / metabolism
  • Reactive Oxygen Species / pharmacology
  • Tight Junctions / metabolism
  • Tissue Inhibitor of Metalloproteinase-1 / metabolism
  • Up-Regulation / physiology


  • Enzyme Inhibitors
  • Reactive Oxygen Species
  • Tissue Inhibitor of Metalloproteinase-1
  • Protein-Tyrosine Kinases
  • Matrix Metalloproteinases