Induction of programmed erythrocyte death by gambogic acid.
Gambogic acid, a xanthone from Garcinia hanburyi, stimulates apoptosis and has thus anticancer potency. Similar to apoptosis of nucleated cells, erythrocytes may undergo apoptosis-like suicidal death or eryptosis, which is characterized by cell shrinkage and cell membrane scrambling leading to phosphatidylserine-exposure at the cell surface. Eryptosis could be triggered by increase of cytosolic Ca(2+)-activity ([Ca(2+)](i)), ceramide formation, ATP-depletion and caspase activation. The present study explored, whether gambogic acid triggers eryptosis of human erythrocytes. [Ca(2+)](i )was estimated utilizing Fluo-3 fluorescence, cell volume from forward scatter, phosphatidylserine-exposure from annexin-V-binding, hemolysis from hemoglobin release, ceramide abundance utilizing antibodies, and cytosolic ATP with luciferin- luciferase. A 48 h exposure to gambogic acid (500 nM) significantly increased [Ca(2+)](i), stimulated ceramide formation, decreased forward scatter and increased annexin-V-binding. Gambogic acid exposure was followed by a slight but significant increase of hemolysis. Gambogic acid did not significantly modify cytosolic ATP-concentration. Removal of extracellular Ca(2+) slightly, but significantly blunted the effect of gambogic acid (500 nM) on annexin-V-binding. The present observations disclose a novel effect of gambogic acid, i.e. stimulation of suicidal death of human erythrocytes or eryptosis, paralleled by Ca(2+)-entry, ceramide formation, cell shrinkage and phosphatidylserine-exposure.
Department of Physiology, University of Tübingen, Gmelinstrasse 5, Tübingen, Germany.
Adrian
A
Lupescu
Kashif
K
Jilani
Christine
C
Zelenak
Mohanad
M
Zbidah
Nazneen
N
Shaik
Florian
F
Lang
D000255:Adenosine Triphosphate / Q000378:metabolism; D000814:Aniline Compounds / Q000737:chemistry; D000818:Animals; D017304:Annexin A5 / Q000378:metabolism; D017209:Apoptosis / Q000187:drug effects*; D002118:Calcium / Q000378:metabolism; D020169:Caspases / Q000378:metabolism; D048429:Cell Size / Q000187:drug effects; D002518:Ceramides / Q000378:metabolism; D004910:Erythrocyte Membrane / Q000187:drug effects / Q000378:metabolism; D004912:Erythrocytes / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D006461:Hemolysis / Q000187:drug effects; D010718:Phosphatidylserines / Q000494:pharmacology; D011485:Protein Binding; D014966:Xanthenes / Q000737:chemistry; D044004:Xanthones / Q000494:pharmacology*
D000814:Aniline Compounds; D017304:Annexin A5; D002518:Ceramides; D010718:Phosphatidylserines; D014966:Xanthenes; D044004:Xanthones; C059715:Fluo-3; D000255:Adenosine Triphosphate; C052659:gambogic acid; D020169:Caspases; D002118:Calcium