Embelin-Induced Phosphatidylserine Translocation in the Erythrocyte Cell Membrane

Abstract

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 Ca²⁺-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. Methods: 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. Results: 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. Conclusions: Embelin stimulates phospholipid scrambling of the erythrocyte cell membrane, an effect involving ceramide formation.

Cytotoxicity of anti-tumor herbal Marsdeniae tenacissimae extract on erythrocytes

“…Mature erythrocytes are flexible and oval biconcave disks, without a cell nucleus, mitochondria, or most organelles, in order to accommodate maximum space for hemoglobin (Ellsworth et al, 2009;Pretorius et al, 2016). Some traditional medicine-induced apoptosis and suicidal erythrocyte death have been reported (Lupescu et al, 2012;Zelenak et al, 2012;Bouguerra et al, 2015). However, other compounds, such as salidroside, protected erythrocytes against oxidative stress and apoptosis (Qian et al, 2011;Shaik et al, 2012).…”

Ceranib‐2‐induced suicidal erythrocyte death

“…Signaling contributing to stimulation of eryptosis includes activated caspases, stimulated activity of casein kinase 1 α , Janus‐activated kinase JAK3, protein kinase C, and p38 kinase, as well as impaired activity of AMP activated kinase AMPK, cGMP‐dependent protein kinase, mitogen‐activated kinase and stress‐activated kinase MSK, PAK2 kinase, and sorafenib/sunitinib sensitive kinases . Eryptosis is triggered by a wide variety of xenobiotics and enhanced eryptosis is observed in several clinical conditions including dehydration, hyperphosphatemia, chronic kidney disease (CKD), hemolytic‐uremic syndrome, diabetes, hepatic failure, malignancy, sepsis, sickle‐cell disease, beta‐thalassemia, Hb‐C and G6PD‐deficiency, as well as Wilsons disease …”

Red Blood Cells Actively Contribute to Blood Coagulation and Thrombus Formation

“…In addition, exposed PS is sought to serve as a signalling component for macrophages to eliminate old or damaged RBCs from the circulation [55][56][57][58]. Since PS-exposing RBCs can adhere to the vascular wall, which may lead to disturbance of the microcirculation [59], the elimination of these cells is a very important mechanism. However, compared to platelets, RBCs have a lower phospholipid scrambling rate (0.45 × 10 3 per second) [51].…”