Actin polymerization, calcium-transients, and phospholipid metabolism in human neutrophils after stimulation with interleukin-8 and N-formyl peptide.
Signal transduction of interleukin-8 (IL-8) was analyzed in neutrophils, and compared with the well known neutrophil activator N-formyl peptide. Stimulation of human neutrophils with IL-8 induced a rapid polymerization of actin as detected by 7-nitrobenz-2-oxa-1,3-diazol-(NBD)-phallacidin staining of f-actin and reduction of monitored right-angle light scatter. Actin polymerization peaked within 10 seconds after the addition of IL-8 and was short-lived as compared to N-formyl peptide-induced stimulation. Analysis of phospholipids by thin-layer chromatography and analysis of deacylation products of lipid extracts by high-pressure liquid chromatography (HPLC) showed that IL-8 triggered a rapid rise of [32P]phosphatidyl-inositol(3,4,5)trisphosphate (PtdInsP3) followed by a slower increase of [32P]phosphatidylinositol(3,4)bisphosphate (PtdIns-3,4-P2) along with a rapid decrease of [32P]phosphatidylinositol(4,5)bisphosphate (PtdIns-4,5-P2). Changes in polyphosphoinositide metabolism were more moderate and transient than those obtained by N-formyl peptide. Moreover, [32P]phosphatidic acid (PA) production stimulated by IL-8 was minimal and transient as compared to the response activated by N-formyl peptide. Both IL-8 and N-formyl peptide induced Ca++ mobilization from intracellular stores, but IL-8 in contrast to N-formyl peptide failed to trigger the secondary influx of Ca++ from the extracellular medium. In summary, IL-8 and N-formyl peptide stimulated similar and distinct patterns of intracellular activation steps. This study indicates that IL-8 is a potent activator of intracellular events presumably required for chemotaxis, but a relatively weak activator for events associated with superoxide anion generation and proinflammatory activity.
Norgauer
J
J
Department of Dermatology, Albert-Ludwigs-University, Freiburg, Germany.
Krutmann
J
J
Dobos
G J
GJ
Traynor-Kaplan
A E
AE
Oades
Z G
ZG
Schraufstätter
I U
IU
D000199:Actins / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism*; D006801:Humans; D016209:Interleukin-8 / Q000494:pharmacology*; D008027:Light; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology*; D009504:Neutrophils / Q000378:metabolism*; D010712:Phosphatidic Acids / Q000378:metabolism; D010716:Phosphatidylinositols / Q000097:blood; D010743:Phospholipids / Q000378:metabolism*; D010761:Phosphorus Radioisotopes / Q000097:blood; D011108:Polymers; D011994:Recombinant Proteins / Q000494:pharmacology; D012542:Scattering, Radiation
D000199:Actins; D016209:Interleukin-8; D010712:Phosphatidic Acids; D010716:Phosphatidylinositols; D010743:Phospholipids; D010761:Phosphorus Radioisotopes; D011108:Polymers; D011994:Recombinant Proteins; D009240:N-Formylmethionine Leucyl-Phenylalanine; D002118:Calcium