5-hydroxyicosatetraenoate stimulates neutrophils by a stereospecific, G protein-linked mechanism

J Biol Chem. 1993 Jul 15;268(20):14708-14.

Abstract

We examined how 5-hydroxyicosatetraenoate (5-HETE) activates human neutrophils (PMN). 5-HETE stimulates PMN to mobilize Ca2+ but has little effect on degranulation or superoxide anion production. It nonetheless stereospecifically induced these responses in cells primed with tumor necrosis factor-alpha and likewise induced PMN plasma membranes to bind 35S-labeled guanosine 5'-O-(thiotriphosphate) (GTP gamma S) and phosphohydrolyze [gamma-32P]GTP. Pertussis toxin blocked GTP gamma S binding responses. Scatchard analyses of GTP gamma S binding data indicated that 5-HETE raised the Ka of high affinity GTP gamma S binding sites without altering these sites' numbers or the parameters of low affinity GTP gamma S binding. Since N-formyl-Met-Leu-Phe, platelet-activating factor, and leukotriene (LT) B4 have these same bioactions, receptors for the latter agents might mediate responses to 5-HETE. However, 5-HETE desensitized degranulation responses to itself but not to the receptor agonists, the receptor agonists desensitized to themselves but not 5-HETE, and a LTB4 antagonist inhibited LTB4 but not 5-HETE in all assays. Finally, PMN and their membranes took up [3H] 5-HETE at 4 or 37 degrees C but, at both temperatures, also acylated the radiolabel into glycerolipids. Acylation nullified assessment of 5-HETE binding and questions reports that measure the cell binding, but not metabolism, of various HETEs. Our studies thus indicate 5-HETE acts by a down-regulatable, G protein-linked mechanism and represent the best available evidence that 5-HETE does not operate through, for example, LTB4 receptors.

Publication types

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

MeSH terms

  • Calcium / metabolism
  • Cells, Cultured
  • GTP-Binding Proteins / metabolism*
  • Guanosine 5'-O-(3-Thiotriphosphate) / metabolism
  • Humans
  • Hydroxyeicosatetraenoic Acids / metabolism
  • Hydroxyeicosatetraenoic Acids / pharmacology*
  • Leukotriene B4 / pharmacology
  • N-Formylmethionine Leucyl-Phenylalanine / pharmacology
  • Neutrophils / drug effects*
  • Neutrophils / metabolism
  • Platelet Activating Factor / pharmacology
  • Superoxides / metabolism
  • Tumor Necrosis Factor-alpha / pharmacology

Substances

  • Hydroxyeicosatetraenoic Acids
  • Platelet Activating Factor
  • Tumor Necrosis Factor-alpha
  • Superoxides
  • Leukotriene B4
  • Guanosine 5'-O-(3-Thiotriphosphate)
  • 5-hydroxy-6,8,11,14-eicosatetraenoic acid
  • N-Formylmethionine Leucyl-Phenylalanine
  • GTP-Binding Proteins
  • Calcium