Relocalization of junctional adhesion molecule A during inflammatory stimulation of brain endothelial cells

Mol Cell Biol. 2012 Sep;32(17):3414-27. doi: 10.1128/MCB.06678-11. Epub 2012 Jun 25.

Abstract

Junctional adhesion molecule A (JAM-A) is a unique tight junction (TJ) transmembrane protein that under basal conditions maintains endothelial cell-cell interactions but under inflammatory conditions acts as a leukocyte adhesion molecule. This study investigates the fate of JAM-A during inflammatory TJ complex remodeling and paracellular route formation in brain endothelial cells. The chemokine (C-C motif) ligand 2 (CCL2) induced JAM-A redistribution from the interendothelial cell area to the apical surface, where JAM-A played a role as a leukocyte adhesion molecule participating in transendothelial cell migration of neutrophils and monocytes. JAM-A redistribution was associated with internalization via macropinocytosis during paracellular route opening. A tracer study with dextran-Texas Red indicated that internalization occurred within a short time period (~10 min) by dextran-positive vesicles and then became sorted to dextran-positive/Rab34-positive/Rab5-positive vesicles and then Rab4-positive endosomes. By ~20 min, most internalized JAM-A moved to the brain endothelial cell apical membrane. Treatment with a macropinocytosis inhibitor, 5-(N-ethyl-N-isopropyl)amiloride, or Rab5/Rab4 depletion with small interfering RNA oligonucleotides prevented JAM-A relocalization, suggesting that macropinocytosis and recycling to the membrane surface occur during JAM-A redistribution. Analysis of the signaling pathways indicated involvement of RhoA and Rho kinase in JAM-A relocalization. These data provide new insights into the molecular and cellular mechanisms involved in blood-brain barrier remodeling during inflammation.

Publication types

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

MeSH terms

  • Animals
  • Brain / blood supply
  • Brain / cytology*
  • Cell Adhesion Molecules / analysis*
  • Cell Adhesion Molecules / immunology*
  • Cell Adhesion Molecules / metabolism
  • Cell Line
  • Cells, Cultured
  • Chemokine CCL2 / immunology
  • Endothelial Cells / cytology*
  • Endothelial Cells / immunology*
  • Endothelial Cells / metabolism
  • Endothelium, Vascular / cytology*
  • Mice
  • Mice, Inbred C57BL
  • Protein Transport
  • Receptors, Cell Surface / analysis*
  • Receptors, Cell Surface / immunology*
  • Receptors, Cell Surface / metabolism
  • Signal Transduction
  • Tight Junctions / immunology*
  • Tight Junctions / metabolism
  • Tight Junctions / ultrastructure

Substances

  • Cell Adhesion Molecules
  • Chemokine CCL2
  • F11r protein, mouse
  • Receptors, Cell Surface