Human and monkey corneal endothelium expression of low-density lipoprotein receptors

Am J Ophthalmol. 1991 Jan 15;111(1):84-91. doi: 10.1016/s0002-9394(14)76902-8.

Abstract

Receptors for low-density lipoprotein are necessary for high-affinity uptake of lipid and protein essential to cell structure and function. Distinct receptors for acetoacetylated low-density lipoprotein internalize oxidized or enzymatically modified low-density lipoprotein and extracellular matrix components. We identified low-density lipoprotein receptors on cultured human and monkey corneal endothelial cells by the avid incorporation of fluorescently labeled low-density lipoprotein that was competitively inhibited by excess unlabeled low-density lipoprotein but not by unlabeled acetoacetylated low-density lipoprotein. Specific uptake of labeled low-density lipoprotein was greatest in nonconfluent, growing cells and increased after low-density lipoprotein deprivation. Intact endothelial monolayers of whole human cornea also incorporated low-density lipoprotein but not acetoacetylated low-density lipoprotein. After scratch injury of human corneas, spreading endothelium adjacent to areas of cell loss internalized more fluorescent low-density lipoprotein than cells distant from the injury. Blood-aqueous barrier breakdown occurring in ocular diseases and after surgical and nonsurgical trauma may allow leakage of circulating low-density lipoprotein, which provides a rich supply of lipid and protein for endothelial use. Efficient, receptor-mediated, low-density lipoprotein uptake may facilitate repair of damaged corneal endothelial membranes and regeneration of intact, functional cell monolayers.

Publication types

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

MeSH terms

  • Acetoacetates / metabolism
  • Animals
  • Carbocyanines
  • Cell Division
  • Cell Survival
  • Cells, Cultured
  • Child, Preschool
  • Cornea / metabolism
  • Corneal Injuries
  • Endothelium, Corneal / injuries
  • Endothelium, Corneal / metabolism*
  • Fluorescent Dyes
  • Humans
  • Lipoproteins, LDL / metabolism
  • Macaca mulatta
  • Rabbits
  • Receptors, LDL / biosynthesis*
  • Wound Healing

Substances

  • Acetoacetates
  • Carbocyanines
  • Fluorescent Dyes
  • Lipoproteins, LDL
  • Receptors, LDL
  • 3,3'-dioctadecylindocarbocyanine