Histamine-induced myosin light chain phosphorylation breaks down the barrier integrity of cultured corneal epithelial cells

Pharm Res. 2007 Oct;24(10):1824-33. doi: 10.1007/s11095-007-9309-1. Epub 2007 May 4.


Purpose: To investigate changes in the phosphorylation of myosin light chain (MLC) in response to histamine and its effect on the barrier integrity of corneal epithelial cells.

Materials and methods: Experiments were performed in bovine corneal epithelial cells (BCEC). RT-PCR and Western blotting were employed to characterize expression of H1 receptors and MLC kinase (MLCK). Phosphorylation of MLC was assessed by urea-glycerol gel electrophoresis and Western blotting. Barrier integrity was determined as permeability to horseradish peroxidase (HRP; 44 kDa) across monolayers grown on porous filters.

Results: Expression of both H1 receptors and MLCK was found in BCEC. Exposure to histamine induced significant MLC phosphorylation concomitant with an increase in HRP permeability. In addition, organization of the cortical actin found in resting cells was disrupted. In contrast to histamine, ATP (a P2Y receptor agonist) induced dephosphorylation of MLC. Pre-exposure to ATP reduced the effect of histamine on HRP permeability and disruption of cortical actin.

Conclusion: MLC phosphorylation, a biochemical pre-requisite for increased contractility of the actin cytoskeleton, led to histamine-induced breakdown of the barrier integrity in the corneal epithelial cells. This is attributed to weakening of the tethering forces at the tight junctions by the centripetal forces produced by increased actin contractility.

Publication types

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

MeSH terms

  • Actins / metabolism
  • Adenosine Triphosphate / analogs & derivatives
  • Adenosine Triphosphate / metabolism
  • Animals
  • Cattle
  • Cells, Cultured
  • Cytoskeleton / metabolism
  • Epithelial Cells / enzymology
  • Epithelial Cells / metabolism*
  • Epithelium, Corneal / cytology
  • Epithelium, Corneal / enzymology
  • Epithelium, Corneal / metabolism*
  • Histamine / metabolism*
  • Horseradish Peroxidase / metabolism
  • Isoenzymes / metabolism
  • Myosin Light Chains / metabolism*
  • Myosin-Light-Chain Kinase / genetics
  • Myosin-Light-Chain Kinase / metabolism*
  • Permeability
  • Phosphorylation
  • RNA, Messenger / metabolism
  • Receptors, Histamine H1 / genetics
  • Receptors, Histamine H1 / metabolism*
  • Receptors, Purinergic P2 / metabolism
  • Tight Junctions / metabolism
  • Time Factors
  • Uridine Triphosphate / metabolism
  • rhoA GTP-Binding Protein / metabolism


  • Actins
  • Isoenzymes
  • Myosin Light Chains
  • RNA, Messenger
  • Receptors, Histamine H1
  • Receptors, Purinergic P2
  • adenosine 5'-O-(3-thiotriphosphate)
  • Histamine
  • Adenosine Triphosphate
  • Horseradish Peroxidase
  • Myosin-Light-Chain Kinase
  • rhoA GTP-Binding Protein
  • Uridine Triphosphate