title: Role of the actin cytoskeleton during respiratory burst in chemoattractant-stimulated neutrophils.
abstract: The aim of this study was to clarify the role of the actin cytoskeleton during chemotactic peptide fMet-Leu-Phe (fMLF)-stimulated respiratory burst in human neutrophil granulocytes. Reactive oxygen species (ROS) was measured as luminol-amplified chemiluminescence (CL) and F-actin content as bodipy phallacidin fluorescence in neutrophils treated with latrunculin B or jasplakinolide, an inhibitor and activator of actin polymerization, respectively. Latrunculin B markedly decreased, whereas jasplakinolide increased, the F-actin content in neutrophils, unstimulated or stimulated with fMLF. Latrunculin B enhanced the fMLF-triggered ROS-production more than tenfold. Jasplakinolide initially inhibited the fMLF-induced CL-response, however, caused a potent second sustained phase (>400% of control). Both actin drugs triggered a substantial CL-response when added 5-25 min after fMLF. This was also valid for chemotactic doses of fMLF, where latrunculin B and jasplakinolide amplified the ROS-production 5-10 times. By using specific signal transduction inhibitors, we found that the NADPH oxidase activation triggered by destabilization of the actin cytoskeleton occurs downstream of phospholipase C and protein kinase C but is mediated by Rho GTPases and tyrosine phosphorylation. In conclusion, rearrangements of the actin cytoskeleton are a prerequisite in connecting ligand/receptor activation, generation of second messengers and assembly of the NADPH oxidase in neutrophil granulocytes.
authors.affiliation: Cardiovascular Inflammation Research Centre, Division of Pharmacology, Department of Medicine and Care, Linköping University, SE-581 85 Linköping, Sweden. torbe@imv.liu.se
authors.forename: Torbjörn
authors.initials: T
authors.lastname: Bengtsson
authors.forename: Kristina
authors.initials: K
authors.lastname: Orselius
authors.forename: Jonas
authors.initials: J
authors.lastname: Wetterö
mesh_terms: D000199:Actins / Q000378:metabolism*; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000494:pharmacology; D002630:Chemotactic Factors / Q000494:pharmacology*; D003599:Cytoskeleton / Q000187:drug effects* / Q000378:metabolism; D047630:Depsipeptides / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D008163:Luminescent Measurements; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology; D019255:NADPH Oxidases / Q000378:metabolism; D009504:Neutrophils / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D016897:Respiratory Burst / Q000187:drug effects*; D015398:Signal Transduction; D013844:Thiazoles / Q000494:pharmacology; D053778:Thiazolidines
chemical_list: D000199:Actins; D019086:Bridged Bicyclo Compounds, Heterocyclic; D002630:Chemotactic Factors; D047630:Depsipeptides; D004791:Enzyme Inhibitors; D013844:Thiazoles; D053778:Thiazolidines; C057531:jasplakinolide; D009240:N-Formylmethionine Leucyl-Phenylalanine; D019255:NADPH Oxidases; C037068:latrunculin B