Withaferin A-stimulated Ca²⁺ entry, ceramide formation and suicidal death of erythrocytes

详细信息    查看全文

• 作者：Kashif Jilani¹ ; Adrian Lupescu¹ ; Mohanad Zbidah ; Nazneen Shaik ; Florian Lang ; ^{florian.lang@uni-tuebingen.de}
• 关键词：Phosphatidylserine ; Withaferin A ; Calcium ; Cell volume ; Eryptosis
• 刊名：Toxicology in Vitro
• 出版年：2013
• 出版时间：February, 2013
• 年：2013
• 卷：27
• 期：1
• 页码：52-58
• 全文大小：607 K

文摘

Withaferin A, a triterpenoid component from Withania somnifera, counteracts malignancy, an effect attributed to stimulation of apoptosis. Withaferin A is partially effective through induction of oxidative stress, altered gene expression and mitochondrial depolarization. Erythrocytes lack mitochondria and nuclei but may enter apoptosis-like eryptosis, a suicidal cell death characterized by cell shrinkage and cell membrane scrambling with phosphatidylserine exposure at the cell surface. Triggers of eryptosis include increase of cytosolic Ca²⁺-activity following activation of oxidant-sensitive Ca²⁺-permeable cation channels, ceramide formation and/or ATP-depletion. The present study explored, whether withaferin A triggers eryptosis. To this end, was estimated from Fluo3-fluorescence, cell volume from forward scatter, phosphatidylserine exposure from annexin-V-binding, hemolysis from hemoglobin release, oxidative stress from DCFDA-fluorescence and ceramide abundance utilizing antibodies. A 48 h exposure to withaferin A significantly decreased forward scatter (at ? 10 ¦ÌM withaferin concentration) and increased (?5 ¦ÌM), ROS-formation (?10 ¦ÌM) ceramide-formation (?10 ¦ÌM) as well as annexin-V-binding (?5 ¦ÌM). Withaferin A treatment was followed by slight but significant increase of hemolysis. Extracellular Ca²⁺ removal, amiloride, and the antioxidant N-acetyl-l-cysteine significantly blunted withaferin A-triggered annexin-V-binding. The present observations reveal that withaferin A triggers suicidal erythrocyte death despite the absence of gene expression and key elements of apoptosis such as mitochondria.