title: Triggering of Suicidal Erythrocyte Death by the Antibiotic Ionophore Nigericin.
abstract: The K(+),H(+) ionophore and antibiotic nigericin has been shown to trigger apoptosis and is thus considered for the treatment of malignancy. Cellular mechanisms involved include induction of oxidative stress, which is known to activate erythrocytic Ca(2+)-permeable unselective cation channels leading to Ca(2+) entry, increase in cytosolic Ca(2+) activity ([Ca(2+)]i) and subsequent stimulation of eryptosis, the suicidal erythrocyte death characterized by cell shrinkage and cell membrane scrambling with phosphatidylserine translocation to the erythrocyte surface. This study explored whether and how nigericin induces eryptosis. Phosphatidylserine exposure at the cell surface was estimated from annexin V binding, cell volume from forward scatter, [Ca(2+)]i from Fluo3 fluorescence, pHi from BCECF fluorescence, ceramide abundance utilizing antibodies and reactive oxygen species (ROS) formation from DCFDA-dependent fluorescence. A 48-hr exposure of human erythrocytes to nigericin significantly increased the percentage of annexin-V-binding cells (0.1-10 nM), significantly decreased forward scatter (0.1-1 nM), significantly decreased cytosolic pH (0.1-1 nM) and significantly increased Fluo3 fluorescence (0.1-10 nM). Nigericin (1 nM) slightly, but significantly, increased ROS, but did not significantly modify ceramide abundance. The effect of nigericin on annexin V binding was significantly blunted, but not abolished by removal of extracellular Ca(2+). The nigericin-induced increase in [Ca(2+)]i and annexin V binding was again significantly blunted but not abolished by the Na(+)/H(+) exchanger inhibitor cariporide (10 μM). Nigericin triggers eryptosis, an effect paralleled by ROS formation, in part dependent on stimulation of Ca(2+) entry, and involving the cariporide-sensitive Na(+)/H(+) exchanger.
authors.affiliation: Department of Physiology, University of Tuebingen, Tuebingen, Germany.
authors.forename: Rosi
authors.initials: R
authors.lastname: Bissinger
authors.affiliation: Department of Physiology, University of Tuebingen, Tuebingen, Germany.
authors.forename: Abaid
authors.initials: A
authors.lastname: Malik
authors.affiliation: Department of Physiology, University of Tuebingen, Tuebingen, Germany.|Laboratoire d'Hématologie Moléculaire et Cellulaire, Institut Pasteur de Tunis, Université de Tunis-El Manar, Tunis, Tunisia.
authors.forename: Ghada
authors.initials: G
authors.lastname: Bouguerra
authors.affiliation: Department of Physiology, University of Tuebingen, Tuebingen, Germany.
authors.forename: Yuetao
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: Department of Physiology, University of Tuebingen, Tuebingen, Germany.
authors.forename: Yogesh
authors.initials: Y
authors.lastname: Singh
authors.affiliation: Laboratoire d'Hématologie Moléculaire et Cellulaire, Institut Pasteur de Tunis, Université de Tunis-El Manar, Tunis, Tunisia.
authors.forename: Salem
authors.initials: S
authors.lastname: Abbès
authors.affiliation: Department of Physiology, University of Tuebingen, Tuebingen, Germany.
authors.forename: Florian
authors.initials: F
authors.lastname: Lang
mesh_terms: D017304:Annexin A5 / Q000378:metabolism; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism; D016923:Cell Death / Q000187:drug effects*; D048429:Cell Size / Q000187:drug effects; D002518:Ceramides / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004912:Erythrocytes / Q000187:drug effects* / Q000473:pathology; D006146:Guanidines / Q000494:pharmacology; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007476:Ionophores / Q000008:administration & dosage / Q000494:pharmacology; D009550:Nigericin / Q000008:administration & dosage / Q000494:pharmacology*; D017382:Reactive Oxygen Species / Q000378:metabolism; D017923:Sodium-Hydrogen Exchangers / Q000378:metabolism; D013450:Sulfones / Q000494:pharmacology
chemical_list: D017304:Annexin A5; D000900:Anti-Bacterial Agents; D002518:Ceramides; D006146:Guanidines; D007476:Ionophores; D017382:Reactive Oxygen Species; D017923:Sodium-Hydrogen Exchangers; D013450:Sulfones; C093373:cariporide; D009550:Nigericin; D002118:Calcium