MEK-1/2 inhibition prevents 5-lipoxygenase translocation in N-formylpeptide-challenged human neutrophils

Int J Biochem Cell Biol. 2000 Oct;32(10):1069-74. doi: 10.1016/s1357-2725(00)00049-2.

Abstract

In order to elucidate the role of mitogen-activated protein kinase kinase (MEK-1/2) in 5-lipoxygenase (5-LO) activation we studied the N-formyl-methionyl-leucyl-phenylalanine (fMLP)-induced 5-LO translocation in human blood neutrophils (PMNs). In non-primed, Ca(2+)-repleted PMNs, fMLP consistently stimulated MEK-1/2 phosphorylation, but induced 5-LO translocation and product formation (430+/-128 pmol; SEM, n=13) only in 13 of 18 PMN preparations from different healthy donors. In fMLP-responsive cells, the MEK-1/2 inhibitor PD098059 (50 microM) attenuated MEK phosphorylation and abolished 5-LO activation at the translocation step. The fMLP-mediated 5-LO product formation was also sensitive to MEK inhibition by U0126 and to p38 inhibition by SB203580. But in contrast to PD098059, U0126 at 10 microM and SB203580 at 20-50 microM impaired 5-LO activity in the cell-free assay setting, suggesting direct actions of higher concentrations of U0126 and SB203580 on 5-LO apart from MEK and p38 inhibition, respectively. These data show that fMLP initiates 5-LO product formation in non-primed, Ca(2+)-repleted human blood PMNs from healthy donors, and that MEK signaling is pivotal, but not sufficient for 5-LO activation in response to the receptor agonist fMLP.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arachidonate 5-Lipoxygenase / metabolism*
  • Butadienes / pharmacology
  • Calcimycin / pharmacology
  • Calcium / metabolism
  • Calcium / pharmacology
  • Cell-Free System
  • Enzyme Activation / drug effects
  • Flavonoids / pharmacology
  • Humans
  • Imidazoles / pharmacology
  • MAP Kinase Kinase 1
  • MAP Kinase Kinase 2
  • MAP Kinase Signaling System / drug effects*
  • Mitogen-Activated Protein Kinase Kinases / antagonists & inhibitors*
  • Mitogen-Activated Protein Kinase Kinases / metabolism
  • N-Formylmethionine Leucyl-Phenylalanine / pharmacology*
  • Neutrophils / drug effects*
  • Neutrophils / enzymology
  • Neutrophils / metabolism
  • Nitriles / pharmacology
  • Phosphorylation / drug effects
  • Protein Serine-Threonine Kinases / antagonists & inhibitors*
  • Protein Serine-Threonine Kinases / metabolism
  • Protein Transport / drug effects
  • Protein-Tyrosine Kinases / antagonists & inhibitors*
  • Protein-Tyrosine Kinases / metabolism
  • Pyridines / pharmacology

Substances

  • Butadienes
  • Flavonoids
  • Imidazoles
  • Nitriles
  • Pyridines
  • U 0126
  • Calcimycin
  • N-Formylmethionine Leucyl-Phenylalanine
  • Arachidonate 5-Lipoxygenase
  • MAP2K2 protein, human
  • Protein-Tyrosine Kinases
  • Protein Serine-Threonine Kinases
  • MAP Kinase Kinase 1
  • MAP Kinase Kinase 2
  • MAP2K1 protein, human
  • Mitogen-Activated Protein Kinase Kinases
  • SB 203580
  • 2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one
  • Calcium