Carbon monoxide-sensitive apoptotic death of erythrocytes.
Carbon monoxide (CO) intoxication severely interferes with the oxygen-transporting function of haemoglobin. Beyond that, CO participates in the regulation of apoptosis. CO could be generated from CO-releasing molecules (CORM), such as the tricarbonyl-dichlororuthenium (II) dimer (CORM-2), which is presently considered for the treatment of vascular dysfunction, inflammation, tissue ischaemia and organ rejection. CORM-2 is at least partially effective by modifying gene expression and mitochondrial potential. Erythrocytes lack nuclei and mitochondria but may undergo suicidal cell death or eryptosis, characterized by cell shrinkage and phospholipid scrambling of the cell membrane. Eryptosis is triggered by the increase in cytosolic Ca²⁺ activity ([Ca²⁺](i)). The present study explored whether CORM-2 influences eryptosis. To this end, [Ca²⁺](i) was estimated from Fluo-3-fluorescence, cell volume from forward scatter, phospholipid scrambling from annexin-V-binding and haemolysis from haemoglobin release. CO-binding haemoglobin (COHb) was estimated utilizing a blood gas analyser. As a result, exposure of erythrocytes for 24 hr to CORM-2 (≥5 μM) significantly increased COHb, [Ca²⁺](i) , forward scatter, annexin-V-binding and haemolysis. Annexin-V-binding was significantly blunted by 100% oxygen and was virtually abolished in the nominal absence of Ca²⁺. In conclusion, CORM-2 stimulates cell membrane scrambling of erythrocytes, an effect largely due to Ca²⁺ entry and partially reversed by O₂.
Department of Physiology, University of Tübingen, Tübingen, Germany.
Elisabeth
E
Lang
Syed M
SM
Qadri
Kashif
K
Jilani
Christine
C
Zelenak
Adrian
A
Lupescu
Erwin
E
Schleicher
Florian
F
Lang
D000328:Adult; D000393:Air Pollutants / Q000378:metabolism / Q000633:toxicity; D017209:Apoptosis / Q000187:drug effects*; D001771:Blood Banks; D020013:Calcium Signaling / Q000187:drug effects; D002248:Carbon Monoxide / Q000378:metabolism / Q000633:toxicity*; D002263:Carboxyhemoglobin / Q000378:metabolism; D002317:Cardiovascular Agents / Q000009:adverse effects* / Q000737:chemistry; D048429:Cell Size / Q000187:drug effects; D004910:Erythrocyte Membrane / Q000187:drug effects / Q000378:metabolism; D004912:Erythrocytes / Q000166:cytology / Q000187:drug effects*; D006461:Hemolysis / Q000187:drug effects; D006801:Humans; D018613:Microscopy, Confocal; D009942:Organometallic Compounds / Q000009:adverse effects* / Q000737:chemistry; D010100:Oxygen / Q000378:metabolism; D010718:Phosphatidylserines / Q000378:metabolism; D013499:Surface Properties
D000393:Air Pollutants; D002317:Cardiovascular Agents; D009942:Organometallic Compounds; D010718:Phosphatidylserines; C447082:tricarbonyldichlororuthenium (II) dimer; D002248:Carbon Monoxide; D002263:Carboxyhemoglobin; D010100:Oxygen