Triggering of Erythrocyte Cell Membrane Scrambling by Emodin

Abstract

Background/Aims: The natural anthraquinone derivative emodin (1,3,8-trihydroxy-6-methylanthraquinone) is a component of several Chinese medicinal herbal preparations utilized for more than 2000 years. The substance has been used against diverse disorders including malignancy, inflammation and microbial infection. The substance is effective in part by triggering suicidal death or apoptosis. Similar to apoptosis of nucleated cells erythrocytes may enter suicidal erythrocyte death or eryptosis, characterized by cell shrinkage and cell membrane scrambling with phosphatidylserine translocation to the erythrocyte surface. Signaling involved in the triggering of eryptosis include increase of cytosolic Ca²⁺ activity ([Ca²⁺]_i), oxidative stress and ceramide. The present study aimed to test, whether emodin induces eryptosis and, if so, to elucidate underlying cellular mechanisms. Methods: Phosphatidylserine abundance at the cell surface was estimated from annexin-V-binding, cell volume from forward scatter, [Ca²⁺]_i from Fluo3-fluorescence, ROS formation from DCFDA dependent fluorescence, and ceramide abundance utilizing specific antibodies. Results: Exposure of human erythrocytes for 48 hours to emodin (≥ 10 µM) significantly increased the percentage of annexin-V-binding cells, and at higher concentrations (≥ 50 µM) significantly increased forward scatter. Emodin significantly increased Fluo3-fluorescence (≥ 10 µM), DCFDA fluorescence (75 µM) and ceramide abundance (75 µM). The effect of emodin on annexin-V-binding was significantly blunted but not abolished by removal of extracellular Ca²⁺. Conclusions: Emodin triggers phospholipid scrambling of the erythrocyte cell membrane, an effect at least in part due to stimulation of Ca²⁺ entry and paralleled by oxidative stress and ceramide appearance at the erythroctye surface.

Emodin Increases Expression of Insulin-Like Growth Factor Binding Protein 1 through Activation of MEK/ERK/AMPKα and Interaction of PPARγ and Sp1 in Lung Cancer

“…Overall, our studies further confirmed the anti-cancer effects of emodin and suggested that this agent can be used as potential therapeutic modality in several cancers [32, 33]. Although there were important discoveries revealed by previous studies indicated potential multiple signaling pathways and molecular genes or proteins that had been involved in the anti-tumor responses and other functions of emodin [8, 10, 34], the detailed molecular mechanisms by which this agent in anti-cancer effects still remained to be elucidated. Consistent with our previous study [11], we observed that emodin induced cell cycle arrest in G2/M phase checkpoint and reduced migration and invasion in lung cancer cells, which was in line with its widely established anti-tumor role of emodin [8-10, 35] implying the possibility of inhibition of both mitotic division and DNA replications which finally reduces cell division rates by emodin in this process.…”

Induction of Apoptosis in HepaRG Cell Line by Aloe-Emodin through Generation of Reactive Oxygen Species and the Mitochondrial Pathway

“…Intracellular accumulation of ROS was determined using fluorescent DCFH-DA [28, 29]. DCFH-DA is a stable, non-polar compound which readily diffuses into cells and is hydrolyzed by intracellular esterase to yield DCFH, which is trapped into the cells.…”

Stimulation of Eryptosis by Afatinib

“…Enhanced eryptosis is observed in diverse clinical conditions including iron deficiency [58], vitamin D excess [117], chronic kidney disease (CKD) [118][119][120][121][122][123], hemolytic-uremic syndrome [124], autoimmune hemolytic anemia [125], diabetes [126], hypertension and dyslipidemia [127], hepatic failure [128], malignancy [129][130][131], arteritis [132], systemic lupus erythematosus [133], sepsis [134,135], malaria [58,136,137], sicklecell disease [58], beta-thalassemia [58], Hb-C and G6PD-deficiency [58], Wilsons disease [134], as well as advanced age [138]. Eryptosis further increases following storage for transfusion [67,68,83,139] and is enhanced in erythrocytes from newborns exposed to oxidative stress [58,140].…”