title: Dicoumarol activates Ca2+-permeable cation channels triggering erythrocyte cell membrane scrambling.
abstract: Dicoumarol, a widely used anticoagulant, may cause anemia, which may result from enhanced erythrocyte loss due to bleeding or due to accelerated erythrocyte death. Erythrocytes may undergo suicidal death or eryptosis, characterized by cell shrinkage and phospholipid scrambling of the cell membrane. Eryptosis may be triggered by increase of cytosolic Ca(2+)-activity ([Ca(2+)](i)). The present study explored, whether dicoumarol induces eryptosis. [Ca(2+)](i) was estimated from Fluo3-fluorescence, cation channel activity utilizing whole cell patch clamp, cell volume from forward scatter, phospholipid scrambling from annexin-V-binding, and hemolysis from haemoglobin release. Exposure of erythrocytes for 48 hours to dicoumarol (=10 μM) significantly increased [Ca(2+)](i), enhanced cation channel activity, decreased forward scatter, triggered annexin-V-binding and elicited hemolysis. Following exposure to 30 μM dicoumarol, annexin-V-binding affected approximately 15%, and hemolysis 2% of treated erythrocytes. The stimulation of annexin-V-binding by dicoumarol was abrogated in the nominal absence of Ca(2+). In conclusion, dicoumarol stimulates suicidal death of erythrocytes by stimulating Ca(2+) entry and subsequent triggering of Ca(2+) dependent cell membrane scrambling.
authors.affiliation: Department of Physiology, University of Tübingen, Tübingen, Germany.
authors.forename: Syed M
authors.initials: SM
authors.lastname: Qadri
authors.forename: Yuliya
authors.initials: Y
authors.lastname: Kucherenko
authors.forename: Christine
authors.initials: C
authors.lastname: Zelenak
authors.forename: Kashif
authors.initials: K
authors.lastname: Jilani
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Lang
authors.forename: Florian
authors.initials: F
authors.lastname: Lang
mesh_terms: D000814:Aniline Compounds / Q000737:chemistry; D017304:Annexin A5 / Q000378:metabolism; D000925:Anticoagulants / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D002118:Calcium / Q000378:metabolism; D048429:Cell Size; D001728:Dicumarol / Q000494:pharmacology*; D004910:Erythrocyte Membrane / Q000187:drug effects*; D004912:Erythrocytes / Q000187:drug effects* / Q000378:metabolism; D006454:Hemoglobins / Q000378:metabolism; D006801:Humans; D007473:Ion Channels / Q000378:metabolism*; D018408:Patch-Clamp Techniques; D011485:Protein Binding; D014966:Xanthenes / Q000737:chemistry
chemical_list: D000814:Aniline Compounds; D017304:Annexin A5; D000925:Anticoagulants; D006454:Hemoglobins; D007473:Ion Channels; D014966:Xanthenes; C059715:Fluo-3; D001728:Dicumarol; D002118:Calcium