Cell adhesion molecule expression in cultured human iris endothelial cells

Invest Ophthalmol Vis Sci. 2001 Nov;42(12):2861-6.


Purpose: To develop a method to isolate human iris microvascular endothelial cells (HIECs) for exploring their constitutive and inflammatory agent-modulated expression of intercellular adhesion molecules (ICAM)-1 and -2, vascular cell adhesion molecule (VCAM)-1, and E-selectin.

Methods: Endothelial cells from collagenase-digested irises were isolated on the basis of their expression of platelet endothelial cell adhesion molecule (PECAM)-1, using antibody-coupled magnetic beads. Cells were characterized as endothelial based on morphologic criteria, their expression of PECAM-1 and von Willebrand factor, their uptake of acetylated low-density lipoprotein, and their ability to form capillary-like networks on a synthetic basement membrane. Constitutive and inflammatory agent-modulated expression of ICAM-1 and -2, VCAM-1, and E-selectin was evaluated by the reverse transcription-polymerase chain reaction, enzyme-linked immunocellular assays (ELICAs), Western blot analysis, and functional studies of leukocyte adhesion to HIEC monolayers.

Results: HIECs constitutively expressed mRNA and protein for ICAM-1 and -2, but only low to nondetectable levels of VCAM-1 or E-selectin. When stimulated with endotoxin- or tumor necrosis factor (TNF)-alpha, ICAM-1, VCAM-1, and E-selectin were potently and time- and dose-dependently upregulated at both the message and protein levels. By contrast, ICAM-2 message and protein were slowly downregulated by inflammatory agents over time, but nonetheless remained present and functional. Overall, cytokine- or endotoxin-activation of HIECs resulted in enhanced adhesiveness for leukocytes.

Conclusions: ICAM-1, VCAM-1, and E-selectin have been previously implicated in mediating anterior ocular inflammation. This is a report of the selective isolation of HIECs, with a demonstration of differential expression and regulation of these adhesion molecules in them. In addition, this is the first demonstration of the regulated expression of ICAM-2 in any ocular microvascular cells.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adolescent
  • Adult
  • Antigens, CD / biosynthesis
  • Antigens, CD / genetics
  • Blotting, Western
  • Cell Adhesion Molecules / biosynthesis*
  • Cell Adhesion Molecules / genetics
  • Cell Separation / methods
  • Cells, Cultured
  • Dose-Response Relationship, Drug
  • E-Selectin / biosynthesis
  • E-Selectin / genetics
  • Endothelium, Vascular / cytology
  • Endothelium, Vascular / drug effects
  • Endothelium, Vascular / metabolism*
  • Endotoxins / pharmacology
  • Enzyme-Linked Immunosorbent Assay
  • Humans
  • Intercellular Adhesion Molecule-1 / biosynthesis
  • Intercellular Adhesion Molecule-1 / genetics
  • Iris / blood supply*
  • RNA, Messenger / biosynthesis
  • Reverse Transcriptase Polymerase Chain Reaction
  • Tumor Necrosis Factor-alpha / pharmacology
  • Up-Regulation
  • Vascular Cell Adhesion Molecule-1 / biosynthesis
  • Vascular Cell Adhesion Molecule-1 / genetics


  • Antigens, CD
  • Cell Adhesion Molecules
  • E-Selectin
  • Endotoxins
  • ICAM2 protein, human
  • RNA, Messenger
  • Tumor Necrosis Factor-alpha
  • Vascular Cell Adhesion Molecule-1
  • Intercellular Adhesion Molecule-1