Platelet-activating factor provokes release of mucin-like glycoproteins from guinea pig respiratory epithelial cells via a lipoxygenase-dependent mechanism

Am J Respir Cell Mol Biol. 1992 May;6(5):550-6. doi: 10.1165/ajrcmb/6.5.550.

Abstract

Primary cultures of guinea pig tracheal epithelial cells maintained in an air/liquid interface system that maintains differentiated characteristics were grown to near confluence and exposed for 1 h to platelet-activating factor (PAF) on both apical and basal sides. PAF provoked release of high-molecular-weight mucin-like glycoproteins (MLG) from the cells, with maximal stimulation occurring at 10(-8) and 10(-9) M. The inactive form of PAF, lyso-PAF, was without effect. Indomethacin, the cyclooxygenase inhibitor, did not affect secretion stimulated by PAF, but nordihydroguiaretic acid (NDGA), a mixed cyclooxygenase and lipoxygenase inhibitor, attenuated secretion stimulated by PAF in a concentration-dependent manner. High performance liquid chromatography assay of the culture medium after addition of PAF revealed increased production of 15-, 12-, and 5-hydroxyeicosatetraenoic acids (15-, 12-, and 5-HETEs). The stimulatory effect of PAF on both mucin secretion and formation of HETEs was inhibited by the PAF receptor antagonists, CV-3988 and Ro 19 3704, with Ro 19 3704 acting at a concentration 10-fold lower than CV-3988 in inhibiting both effects. When added exogenously to the cell cultures, the combination of 5-, 12-, and 15-HETEs stimulated MLG release in a concentration-dependent manner. The results suggest that PAF stimulates release of MLG by guinea pig airway epithelium in vitro by a mechanism involving binding of PAF to receptors on epithelial cell surfaces, stimulation of lipoxygenase metabolism of arachidonic acid to HETEs within the epithelium, and stimulation of secretion by these epithelial-derived HETEs via an autocrine or paracrine mechanism.

Publication types

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

MeSH terms

  • Animals
  • Cells, Cultured
  • Chromatography, High Pressure Liquid
  • Cyclooxygenase Inhibitors / pharmacology
  • Epithelium / metabolism
  • Glyceryl Ethers / pharmacology
  • Guinea Pigs
  • Hydroxyeicosatetraenoic Acids / metabolism*
  • In Vitro Techniques
  • Indomethacin / pharmacology
  • Lipoxygenase / physiology*
  • Lipoxygenase Inhibitors / pharmacology
  • Masoprocol / pharmacology
  • Mucins / metabolism*
  • Phospholipid Ethers / pharmacology
  • Platelet Activating Factor / pharmacology*
  • Platelet Membrane Glycoproteins*
  • Receptors, Cell Surface / antagonists & inhibitors
  • Receptors, G-Protein-Coupled*
  • Thiazoles / pharmacology
  • Trachea / metabolism*

Substances

  • Cyclooxygenase Inhibitors
  • Glyceryl Ethers
  • Hydroxyeicosatetraenoic Acids
  • Lipoxygenase Inhibitors
  • Mucins
  • Phospholipid Ethers
  • Platelet Activating Factor
  • Platelet Membrane Glycoproteins
  • Receptors, Cell Surface
  • Receptors, G-Protein-Coupled
  • Thiazoles
  • platelet activating factor receptor
  • Ro 19-3704
  • Masoprocol
  • CV 3988
  • Lipoxygenase
  • Indomethacin