In Vitro Induction of Erythrocyte Phosphatidylserine Translocation by the Natural Naphthoquinone Shikonin

Toxins

Adrian Lupescu¹  Rosi Bissinger¹  Kashif Jilani¹ 

[1] Department of Physiology, University of Tuebingen, Gmelinstreet 5, Tuebingen 72076, Germany;

关键词: phosphatidylserine;    shikonin;    calcium;    ceramide;    cell volume;    eryptosis;   

DOI  :  10.3390/toxins6051559

来源: mdpi

【 摘 要 】

Shikonin, the most important component of Lithospermum erythrorhizon, has previously been shown to exert antioxidant, anti-inflammatory, antithrombotic, antiviral, antimicrobial and anticancer effects. The anticancer effect has been attributed to the stimulation of suicidal cell death or apoptosis. Similar to the apoptosis of nucleated cells, erythrocytes may experience eryptosis, the suicidal erythrocyte death characterized by cell shrinkage and by phosphatidylserine translocation to the erythrocyte surface. Triggers of eryptosis include the increase of cytosolic Ca²⁺-activity ([Ca²⁺]_i) and ceramide formation. The present study explored whether Shikonin stimulates eryptosis. To this end, Fluo 3 fluorescence was measured to quantify [Ca²⁺]_i, forward scatter to estimate cell volume, annexin V binding to identify phosphatidylserine-exposing erythrocytes, hemoglobin release to determine hemolysis and antibodies to quantify ceramide abundance. As a result, a 48 h exposure of human erythrocytes to Shikonin (1 µM) significantly increased [Ca²⁺]_i, increased ceramide abundance, decreased forward scatter and increased annexin V binding. The effect of Shikonin (1 µM) on annexin V binding was significantly blunted, but not abolished by the removal of extracellular Ca²⁺. In conclusion, Shikonin stimulates suicidal erythrocyte death or eryptosis, an effect at least partially due to the stimulation of Ca²⁺ entry and ceramide formation.

【 授权许可】

CC BY   
© 2014 by the authors; licensee MDPI, Basel, Switzerland.