title: Interleukin-8 primes oxidative burst in neutrophil-like HL-60 through changes in cytosolic calcium.
abstract: In response to a variety of stimuli, neutrophils release large amount of reactive oxygen species (ROS) generated by NADPH oxidase. This process known as the respiratory burst is dependent on cytosolic free calcium concentration ([Ca(2+)](i)). Proinflammatory cytokines such as interleukin-8 (IL-8) may modulate ROS generation through a priming phenomenon. The aim of this study was to determine the effect of human IL-8 on ROS production in neutrophil-like dimethylsulfoxide-differentiated HL-60 cells (not equalHL-60 cells) and further to examine the role of Ca(2+) mobilization during the priming. IL-8 at 10 nM induced no ROS production but a [Ca(2+)](i) rise (254 +/- 36 nM). IL-8 induced a strongly enhanced (2 fold) ROS release during stimulation with 1 microM of N-formyl-L-methionyl-L-leucyl-L-phenylalanine (fMLF). This potentiation of ROS production is dependent of extracellular Ca(2+) (17.0+/-4.5 arbitrary units (A.U.) in the absence of Ca(2+) versus 56.6 +/- 3.9 A.U. in the presence of 1.25 mM of Ca(2+)). Also, IL-8 enhanced fMLF-stimulated increase in [Ca(2+)](i) (375 +/- 35 versus 245 +/- 21 nM, 0.1 microM of fMLF). IL-8 had no effect on not equalHL-60 cells in response to 1 microM of thapsigargin (472 +/- 66 versus 470 +/- 60 nM). In conclusion, Ca(2+) influx is necessary for a full induction of neutrophil priming by IL-8.
authors.affiliation: Laboratoire de Biologie et Physiologie Intégrée, Faculté des Sciences, de la Technologie et de la Communication, Université du Luxembourg.
authors.forename: S
authors.initials: S
authors.lastname: Bréchard
authors.forename: J-L
authors.initials: JL
authors.lastname: Bueb
authors.forename: E J
authors.initials: EJ
authors.lastname: Tschirhart
mesh_terms: D002118:Calcium / Q000502:physiology*; D016257:Fura-2; D018922:HL-60 Cells; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism; D016209:Interleukin-8 / Q000502:physiology*; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology; D009504:Neutrophils / Q000187:drug effects / Q000502:physiology*; D010078:Oxazines; D017382:Reactive Oxygen Species / Q000378:metabolism; D016897:Respiratory Burst / Q000502:physiology*
chemical_list: D016209:Interleukin-8; D010078:Oxazines; D017382:Reactive Oxygen Species; C470430:Amplex Red; D009240:N-Formylmethionine Leucyl-Phenylalanine; D006861:Hydrogen Peroxide; D002118:Calcium; D016257:Fura-2