Platelet-activating factor biosynthesis induced by various stimuli in human HaCaT keratinocytes

Jeffrey B. Travers, Kathleen A. Harrison, Christopher A. Johnson, Keith L. Clay, Joseph G. Morelli, Robert C. Murphy

Research output: Contribution to journalArticle

42 Scopus citations

Abstract

Platelet-activating factor (PAF) is a potent inflammatory mediator that is thought to play a role in cutaneous inflammation. These studies used mass spectrometry to examine the molecular species of PAF precursor glycerophosphocholine lipids (GPC) as well as the biosynthesis of PAF and other sn-2 acetyl-GPC in a human keratinocyte-derived cell line (HaCaT keratinocytes). Approximately 28% of HaCaT keratinocyte GPC consisted of 1-alkyl species, and the relative amounts of the sn-1 alkyl constituents of the PAF precursor 1-alkyl-2-acyl-GPC were as follows: hexadecyl > octadecenyl > octadecyl. Ionophore (A23187)-stimulated HaCaT keratinocytes synthesized both PAF (1-hexadecyl, 1-octadecenyl, and 1-octadecyl species) and less potent 1-acyl analogs (1-palmitoyl, 1-oleoyl, and 1-stearoyl species). PAF production was rapid and maximal by 10 min. The major species of sn-2 acetyl-GPC at 2.5 min were 1-hexadecyl-2-acetyl-GPC (2.2 ng/106 cells) and 1-palmitoyl-2-acetyl-GPC (2.4 ng/106 cells). HaCaT keratiraocytes also synthesized PAF and 1-acyl PAF analogs when stimulated with the peptide growth factor endothelin-1 and the nonhydrolyzable PAF receptor agonist carbamyl-PAF. Both 1-hexadecyl-2-acetyl-GPC and 1-palmitoyl-2-acetyl-GPC stimulated intracellular calcium mobilization in HaCaT cells, indicating that these sn-2 acetyl-GPC act in autocrine fashion, These studies revealed that the human keratinocyte-derived cell line HaCaT can synthesize significant amounts of PAF and 1-acyl analogs in vitro from both nonspecific (A23187) and specific (endothelin-1, carbamyl-PAF) stimulation, suggesting a role for this inflammatory lipid mediator in keratinocyte pathophysiology.

Original languageEnglish (US)
Pages (from-to)88-94
Number of pages7
JournalJournal of Investigative Dermatology
Volume107
Issue number1
DOIs
StatePublished - Jan 1 1996

Keywords

  • Endothelin
  • Glycerophospholipids
  • Intracellular calcium
  • Mass spectrometry
  • Molecular species

ASJC Scopus subject areas

  • Dermatology

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