title: Induction of suicidal erythrocyte death by nelfinavir.
abstract: The HIV protease inhibitor, nelfinavir, primarily used for the treatment of HIV infections, has later been shown to be effective in various infectious diseases including malaria. Nelfinavir may trigger mitochondria-independent cell death. Erythrocytes may undergo eryptosis, a mitochondria-independent suicidal cell death characterized by cell shrinkage and phosphatidylserine translocation to the erythrocyte surface. Triggers of eryptosis include oxidative stress and increase of cytosolic Ca2+-activity ([Ca2+]i). During malaria, accelerated death of infected erythrocytes may decrease parasitemia and thus favorably influence the clinical course of the disease. In the present study, phosphatidylserine abundance at the cell surface was estimated from annexin V binding, cell volume from forward scatter, reactive oxidant species (ROS) from 2',7'-dichlorodihydrofluorescein diacetate (DCFDA) fluorescence, and [Ca2+]i from Fluo3-fluorescence. A 48 h treatment of human erythrocytes with nelfinavir significantly increased the percentage of annexin-V-binding cells (≥5µg/mL), significantly decreased forward scatter (≥2.5µg/mL), significantly increased ROS abundance (10 µg/mL), and significantly increased [Ca2+]i (≥5 µg/mL). The up-regulation of annexin-V-binding following nelfinavir treatment was significantly blunted, but not abolished by either addition of the antioxidant N-acetylcysteine (1 mM) or removal of extracellular Ca2+. In conclusion, exposure of erythrocytes to nelfinavir induces oxidative stress and Ca2+ entry, thus leading to suicidal erythrocyte death characterized by erythrocyte shrinkage and erythrocyte membrane scrambling.
authors.affiliation: Department of Physiology, University of Tuebingen, Gmelinstr. 5, 72076 Tuebingen, Germany. ro.bissinger@gmx.de.
authors.forename: Rosi
authors.initials: R
authors.lastname: Bissinger
authors.affiliation: Department of Physiology, University of Tuebingen, Gmelinstr. 5, 72076 Tuebingen, Germany. Sabi-W@gmx.de.
authors.forename: Sabrina
authors.initials: S
authors.lastname: Waibel
authors.affiliation: Department of Physiology, University of Tuebingen, Gmelinstr. 5, 72076 Tuebingen, Germany. florian.lang@uni-tuebingen.de.
authors.forename: Florian
authors.initials: F
authors.lastname: Lang
mesh_terms: D002118:Calcium / Q000378:metabolism; D016923:Cell Death / Q000187:drug effects; D002478:Cells, Cultured; D004912:Erythrocytes / Q000187:drug effects* / Q000378:metabolism; D017320:HIV Protease Inhibitors / Q000633:toxicity*; D006461:Hemolysis / Q000187:drug effects; D006801:Humans; D019888:Nelfinavir / Q000633:toxicity*; D018384:Oxidative Stress / Q000187:drug effects; D010718:Phosphatidylserines / Q000378:metabolism
chemical_list: D017320:HIV Protease Inhibitors; D010718:Phosphatidylserines; D019888:Nelfinavir; D002118:Calcium
keywords: ROS; calcium; cell volume; eryptosis; malaria; oxidative stress; phosphatidylserine