Bouguerra Ghada, Aljanadi Omar, Bissinger Rosi, Abbès Salem, Lang Florian
Cell Physiol Biochem. 2015;37(4):1629-40. doi: 10.1159/000438529. Epub 2015 Nov 5.
BACKGROUND/AIMS: The antihelminthic, contraceptive, anti-inflammatory and anticancer phytochemical embelin is at least in part effective against malignancy by inducing suicidal death or apoptosis of tumor cells. Erythrocytes are similarly able to enter suicidal death or eryptosis, which is characterized by cell shrinkage and cell membrane scrambling with phosphatidylserine translocation to the erythrocyte surface. Signaling of eryptosis includes increase of cytosolic Ca(2+)-activity ([Ca2+]i), ceramide formation, oxidative stress as well as activation of p38 kinase and protein kinase C (PKC). The present study tested, whether and how embelin induces eryptosis.
Phosphatidylserine exposure at the cell surface was estimated from annexin V binding, cell volume from forward scatter, [Ca2+]i from Fluo3-fluorescence, ceramide abundance utilizing specific antibodies and reactive oxygen species (ROS) from 2',7'-dichlorodihydrofluorescein diacetate (DCFDA) fluorescence.
A 48 hours exposure of human erythrocytes to embelin (≥25 µM) significantly increased the percentage of annexin-V-binding cells and hemolysis. Embelin did not significantly modify [Ca2+]i. The effect of embelin on annexin-V-binding was not blunted by removal of extracellular Ca2+, by p38 kinase inhibitor SB203580 (2 µM) or by PKC inhibitor staurosporine (1 µM). Embelin did, however, significantly increase the ceramide abundance.
Embelin stimulates phospholipid scrambling of the erythrocyte cell membrane, an effect involving ceramide formation.
背景/目的：抗蠕虫、避孕、抗炎和抗癌的植物化学物质紫铆因至少部分通过诱导肿瘤细胞自杀性死亡或凋亡而对恶性肿瘤有效。红细胞同样能够进入自杀性死亡或红细胞凋亡，其特征是细胞收缩和细胞膜紊乱，磷脂酰丝氨酸转运到红细胞表面。红细胞凋亡的信号包括胞质Ca(2+)活性（[Ca2+]i）增加、神经酰胺形成、氧化应激以及p38激酶和蛋白激酶C（PKC）的激活。本研究测试了紫铆因是否以及如何诱导红细胞凋亡。
通过膜联蛋白V结合估计细胞表面磷脂酰丝氨酸暴露，通过前向散射估计细胞体积，通过Fluo3荧光估计[Ca2+]i，利用特异性抗体估计神经酰胺丰度，通过2',7'-二氯二氢荧光素二乙酸酯（DCFDA）荧光估计活性氧（ROS）。
人红细胞暴露于紫铆因（≥25 µM）48小时后，膜联蛋白V结合细胞的百分比和溶血率显著增加。紫铆因对[Ca2+]i没有显著影响。去除细胞外Ca2+、使用p38激酶抑制剂SB203580（2 µM）或PKC抑制剂星形孢菌素（1 µM）均不能减弱紫铆因对膜联蛋白V结合的影响。然而，紫铆因确实显著增加了神经酰胺的丰度。
紫铆因刺激红细胞细胞膜的磷脂紊乱，这一效应涉及神经酰胺的形成。
