title: Stimulation of erythrocyte phospholipid scrambling by enniatin A.
abstract: METHODS
  Enniatin A, a peptide antibiotic and common food contaminant, triggers mitochondrial dysfunction and apoptosis. Even though lacking mitochondria, erythrocytes may similarly undergo suicidal cell death or eryptosis. Eryptosis is characterized by cell shrinkage and cell membrane phospholipid scrambling. Triggers of phospholipid scrambling include energy depletion and increase in cytosolic Ca(2+) activity ([Ca(2+) ](i) ). The present study explored whether enniatin A triggers phospholipid scrambling.
  
  
  RESULTS
  Phospholipid scrambling was estimated from annexin-V-binding, cell volume from forward scatter (FSC), [Ca(2+) ](i) from Fluo3-fluorescence, cytosolic ATP-concentration ([ATP](i) ) using a luciferase assay and hemolysis from hemoglobin release. Exposure of erythrocytes for 48 h to enniatin A (≥ 2.5 μM) significantly increased [Ca(2+) ](i) , decreased [ATP](i) , decreased FSC, triggered annexin-V-binding and elicited hemolysis. Annexin-V-binding affected 25%, and hemolysis 2% of treated erythrocytes. Decreased [ATP](i) by glucose depletion for 48 h was similarly followed by increased [Ca(2+) ](i) , decreased FSC and annexin-V-binding. Enniatin A augmented the effect on [Ca(2+) ](i) and annexin-V-binding, but not on FSC. Annexin-V-binding was blunted by Ca(2+) removal, by the cation channel inhibitor amiloride (1 mM), by the protein kinase C inhibitor staurosporine (500 nM) but not by the pancaspase inhibitor zVAD (10 μM).
  
  
  CONCLUSIONS
  The food contaminant enniatin A triggers ATP depletion and increases cytosolic Ca(2+) activity, effects resulting in suicidal erythrocyte death.
authors.affiliation: Department of Physiology, University of Tuebingen, Tuebingen, Germany.
authors.forename: Kashif
authors.initials: K
authors.lastname: Jilani
authors.forename: Syed M
authors.initials: SM
authors.lastname: Qadri
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Lang
authors.forename: Christine
authors.initials: C
authors.lastname: Zelenak
authors.forename: Anand
authors.initials: A
authors.lastname: Rotte
authors.forename: Diwakar
authors.initials: D
authors.lastname: Bobbala
authors.forename: Florian
authors.initials: F
authors.lastname: Lang
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000584:Amiloride / Q000494:pharmacology; D017304:Annexin A5 / Q000378:metabolism; D002118:Calcium / Q000378:metabolism*; D061945:Caspase Inhibitors; D048429:Cell Size / Q000187:drug effects; D003600:Cytosol / Q000187:drug effects / Q000378:metabolism; D047630:Depsipeptides / Q000494:pharmacology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004912:Erythrocytes / Q000187:drug effects* / Q000378:metabolism; D006801:Humans; D010718:Phosphatidylserines / Q000378:metabolism; D010743:Phospholipids / Q000378:metabolism*; D011493:Protein Kinase C / Q000037:antagonists & inhibitors; D026941:Sodium Channel Blockers / Q000494:pharmacology; D019311:Staurosporine / Q000494:pharmacology
chemical_list: D017304:Annexin A5; D061945:Caspase Inhibitors; D047630:Depsipeptides; D004791:Enzyme Inhibitors; D010718:Phosphatidylserines; D010743:Phospholipids; D026941:Sodium Channel Blockers; C100264:enniatins; D000584:Amiloride; D000255:Adenosine Triphosphate; D011493:Protein Kinase C; D019311:Staurosporine; D002118:Calcium