title: Stimulation of suicidal erythrocyte death by lipoxygenase inhibitor Bay-Y5884.
abstract: The prostaglandin PGE(2), a metabolite of the cyclooxygenase pathway, activates Ca(2+)-permeable cation channels in erythrocyte cell membranes leading to entry of Ca(2+) with subsequent eryptosis, i.e. cell shrinkage, breakdown of phosphatidylserine (PS) asymmetry and membrane blebbing, all features typical for apoptosis in nucleated cells. PS exposing cells are recognized by macrophages, engulfed, degraded and thus cleared from circulating blood. The present study explored whether the specific lipoxygenase inhibitor Bay-Y5884 influences eryptosis. As determined by competitive ELISA, Bay-Y5884 (20 microM) enhanced the release of PGE(2) from human erythrocytes. According to whole-cell patch-clamp, Bay-Y5884 (20 microM) activated nonselective cation channels. The effect of Bay-Y5884 on cation channels was abolished by the cyclooxygenase inhibitor diclophenac (10 microM). Bay-Y5884 (30-40 microM) significantly increased erythrocyte free Ca(2+) concentration and PS exposure as analyzed in flow cytometry by Fluo3 fluorescence and annexin-V binding, respectively. PS exposure triggered by 20 microM (but not by 40 microM) Bay-Y5884 was blunted by cyclooxygenase inhibitors acetylsalicylic acid (50 microM) and diclophenac (10 microM). In conclusion, the lipoxygenase inhibitor Bay-Y5884 enhances erythrocyte PGE(2) formation with subsequent activation of non-selective cation channels, Ca(2+) entry and phospholipid scrambling.
authors.affiliation: Department of Physiology, University of Tübingen, Tübingen, Germany.
authors.forename: Ekaterina
authors.initials: E
authors.lastname: Shumilina
authors.forename: Valentin
authors.initials: V
authors.lastname: Kiedaisch
authors.forename: Ahmad
authors.initials: A
authors.lastname: Akkel
authors.forename: Philipp
authors.initials: P
authors.lastname: Lang
authors.forename: Tobias
authors.initials: T
authors.lastname: Hermle
authors.forename: Daniela S
authors.initials: DS
authors.lastname: Kempe
authors.forename: Stephan M
authors.initials: SM
authors.lastname: Huber
authors.forename: Thomas
authors.initials: T
authors.lastname: Wieder
authors.forename: Stefan
authors.initials: S
authors.lastname: Laufer
authors.forename: Florian
authors.initials: F
authors.lastname: Lang
mesh_terms: D001241:Aspirin / Q000494:pharmacology; D001692:Biological Transport / Q000187:drug effects; D002118:Calcium / Q000378:metabolism; D016923:Cell Death; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology; D004008:Diclofenac / Q000494:pharmacology; D015232:Dinoprostone / Q000378:metabolism*; D004912:Erythrocytes / Q000187:drug effects* / Q000378:metabolism; D006801:Humans; D016859:Lipoxygenase Inhibitors / Q000494:pharmacology*; D018408:Patch-Clamp Techniques; D010718:Phosphatidylserines / Q000494:pharmacology; D024681:Potassium Channels, Calcium-Activated / Q000819:agonists
chemical_list: D016861:Cyclooxygenase Inhibitors; D016859:Lipoxygenase Inhibitors; D010718:Phosphatidylserines; D024681:Potassium Channels, Calcium-Activated; D004008:Diclofenac; D015232:Dinoprostone; D001241:Aspirin; D002118:Calcium