title: Triggering of Erythrocyte Death by Triparanol.
abstract: The cholesterol synthesis inhibitor Triparanol has been shown to trigger apoptosis in several malignancies. Similar to the apoptosis of nucleated cells, erythrocytes may enter eryptosis, the suicidal death characterized by cell shrinkage and cell membrane scrambling with phosphatidylserine translocation to the erythrocyte surface. Triggers of eryptosis include oxidative stress which may activate erythrocytic Ca(2+) permeable unselective cation channels with subsequent Ca(2+) entry and increase of cytosolic Ca(2+) activity ([Ca(2+)]i). The present study explored whether and how Triparanol induces eryptosis. To this end, phosphatidylserine exposure at the cell surface was estimated from annexin-V-binding, cell volume from forward scatter, hemolysis from hemoglobin release, [Ca(2+)]i from Fluo3-fluorescence, and ROS formation from 2',7'-dichlorodihydrofluorescein diacetate (DCFDA) dependent fluorescence. As a result, a 48 h exposure of human erythrocytes to Triparanol (20 µM) significantly increased DCFDA fluorescence and significantly increased Fluo3-fluorescence. Triparanol (15 µM) significantly increased the percentage of annexin-V-binding cells, and significantly decreased the forward scatter. The effect of Triparanol on annexin-V-binding was significantly blunted, but not abolished by removal of extracellular Ca(2+). In conclusion, Triparanol leads to eryptosis, the suicidal erythrocyte death characterized by cell shrinkage and phospholipid scrambling of the erythrocyte cell membrane. Triparanol is at least in part effective by stimulating ROS formation and Ca(2+) entry.
authors: Department of Physiology, University of Tübingen, Gmelinstr. 5, 72076 Tuebingen, Germany. caterina.manna@unina2.it.|Department of Biochemistry, Biophysics and General Pathology, School of Medicine and Surgery, Second University of Naples, Via L. De Crecchio 7, 80138 Naples, Italy. caterina.manna@unina2.it.
authors: Arbace
authors: A
authors: Officioso
authors: Department of Biochemistry, Biophysics and General Pathology, School of Medicine and Surgery, Second University of Naples, Via L. De Crecchio 7, 80138 Naples, Italy. caterina.manna@unina2.it.
authors: Caterina
authors: C
authors: Manna
authors: Department of Physiology, University of Tübingen, Gmelinstr. 5, 72076 Tuebingen, Germany. kossai.z@gmail.com.
authors: Kousi
authors: K
authors: Alzoubi
authors: Department of Physiology, University of Tübingen, Gmelinstr. 5, 72076 Tuebingen, Germany. arbace.officioso@gmail.com.
authors: Florian
authors: F
authors: Lang
mesh_terms: D002118:Calcium / Q000378:metabolism; D016923:Cell Death / Q000187:drug effects; D048429:Cell Size / Q000187:drug effects; D002478:Cells, Cultured; D004910:Erythrocyte Membrane / Q000378:metabolism; D004912:Erythrocytes / Q000187:drug effects* / Q000378:metabolism; D005978:Glutathione / Q000378:metabolism; D006461:Hemolysis / Q000187:drug effects; D006801:Humans; D000960:Hypolipidemic Agents / Q000633:toxicity*; D010718:Phosphatidylserines / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D014308:Triparanol / Q000633:toxicity*
chemical_list: D000960:Hypolipidemic Agents; D010718:Phosphatidylserines; D017382:Reactive Oxygen Species; D014308:Triparanol; D005978:Glutathione; D002118:Calcium
keywords: calcium; cell volume; eryptosis; oxidative stress; phosphatidylserine