title: Stimulation of suicidal erythrocyte death by fumagillin.
abstract: Fumagillin, a cyclohexane isolated from fungus Aspergillus fumigatus, has anti-infective and anti-cancer potency. Fumagillin is at least partially effective by inducing suicidal death or apoptosis. In analogy to apoptosis of nucleated cells, eryptosis is the suicidal death of erythrocytes characterized by cell shrinkage and cell membrane scrambling with phosphatidylserine exposure at the cell surface. Stimulators of eryptosis include increase of cytosolic Ca(2+)-activity ([Ca(2+)](i)) and ceramide. The present study explored whether fumagillin (5-100 μM) could stimulate eryptosis. To this end, [Ca(2+)](i) was estimated from Fluo3 fluorescence, ceramide by utilizing specific antibodies, cell volume from forward scatter, phosphatidylserine exposure from annexin V binding and haemolysis from haemoglobin release. As a result, a 48-hr exposure to fumagillin significantly increased [Ca(2+)](i) (≥10 μM), enhanced ceramide abundance (100 μM), triggered annexin V binding (≥10 μM) and decreased forward scatter (≥10 μM). Fumagillin exposure was followed by slight but significant increase of haemolysis. Removal of extracellular Ca(2+) significantly blunted but did not abolish the effect of fumagillin (100 μM) on annexin V binding. The present observations disclose a novel effect of fumagillin, that is, stimulation of eryptosis, paralleled by Ca(2+) entry, ceramide formation, phosphatidylserine exposure and decrease of cell volume.
authors.affiliation: Department of Physiology, University of Tuebingen, Tuebingen, Germany.
authors.forename: Mohanad
authors.initials: M
authors.lastname: Zbidah
authors.forename: Adrian
authors.initials: A
authors.lastname: Lupescu
authors.forename: Kashif
authors.initials: K
authors.lastname: Jilani
authors.forename: Florian
authors.initials: F
authors.lastname: Lang
mesh_terms: D017304:Annexin A5 / Q000378:metabolism; D000900:Anti-Bacterial Agents / Q000633:toxicity*; D002118:Calcium / Q000378:metabolism; D016923:Cell Death / Q000187:drug effects; D048429:Cell Size / Q000187:drug effects; D002518:Ceramides / Q000378:metabolism; D003510:Cyclohexanes / Q000633:toxicity*; D004305:Dose-Response Relationship, Drug; D004912:Erythrocytes / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D005231:Fatty Acids, Unsaturated / Q000633:toxicity*; D005434:Flow Cytometry / Q000379:methods; D006461:Hemolysis / Q000187:drug effects; D006801:Humans; D010718:Phosphatidylserines / Q000378:metabolism; D011485:Protein Binding; D012717:Sesquiterpenes / Q000633:toxicity
chemical_list: D017304:Annexin A5; D000900:Anti-Bacterial Agents; D002518:Ceramides; D003510:Cyclohexanes; D005231:Fatty Acids, Unsaturated; D010718:Phosphatidylserines; D012717:Sesquiterpenes; C026211:fumagillin; D002118:Calcium