Stimulation of protein kinase C redistribution and inhibition of leukotriene B4-induced inositol 1,4,5-trisphosphate generation in human neutrophils by lipoxin A4

Br J Pharmacol. 1996 Mar;117(6):1334-40. doi: 10.1111/j.1476-5381.1996.tb16733.x.

Abstract

1. To test the hypothesis that protein kinase C (PKC) is involved in the inhibitory actions of lipoxin A4 (LXA4) on second messenger generation, we studied the effects of LXA4 on PKC in human neutrophils and on leukotriene B4 (LTB4)-stimulated inositol-1,4,5-trisphosphate (Ins(1,4,5)P3) generation. 2. LXA4, 1 microM, caused a fall in cytosolic PKC-dependent histone phosphorylating activity to 23.5% of basal levels. 3. LXA4, caused an increase in particulate PKC-dependent histone phosphorylating activity with a bell-shaped dose-response fashion; maximal stimulation was observed at 10 nM LXA4. 4. Western blot analysis with affinity-purified antibodies to alpha- and beta-PKC showed that only the beta-PKC isotype was translocated by LXA4. 5. LXA4 inhibited LTB4-stimulated Ins(1,4,5)P3 generation in a bell-shaped fashion with maximal inhibition at 1 nM LXA4. The observed inhibition was dose-dependently removed by pre-incubation with a PKC inhibitor (Ro-31-8220). 6. These results show that LXA4 activates PKC in whole cells and supports a role for PKC activation in the inhibitory action of LXA4 on LTB4-induced Ins(1,4,5)P3 generation. 7. LXA4 (1-1000 nM) pre-incubation did not affect specific binding of [3H]-LTB4 to neutrophils. Thus, the inhibitory effect of LXA4 on LTB4-stimulated Ins(1,4,5)P3 generation could not be attributed to an effect on LTB4 receptors.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Blotting, Western
  • Dose-Response Relationship, Drug
  • Drug Antagonism
  • Enzyme Inhibitors / pharmacology
  • Humans
  • Hydroxyeicosatetraenoic Acids / pharmacology*
  • Indoles / pharmacology
  • Inositol 1,4,5-Trisphosphate / biosynthesis*
  • Leukotriene B4 / antagonists & inhibitors
  • Leukotriene B4 / pharmacology*
  • Lipoxins*
  • Neutrophils / drug effects*
  • Neutrophils / metabolism
  • Protein Kinase C / antagonists & inhibitors
  • Protein Kinase C / metabolism*
  • Receptors, Leukotriene B4 / drug effects*
  • Receptors, Leukotriene B4 / metabolism

Substances

  • Enzyme Inhibitors
  • Hydroxyeicosatetraenoic Acids
  • Indoles
  • Lipoxins
  • Receptors, Leukotriene B4
  • lipoxin A4
  • Leukotriene B4
  • Inositol 1,4,5-Trisphosphate
  • Protein Kinase C
  • Ro 31-8220