Oxysterol Mixture in Hypercholesterolemia-Relevant Proportion Causes Oxidative Stress-Dependent Eryptosis

Cellular Physiology and Biochemistry

关键词: Hypercholesterolemia;    Human red blood cell;    Oxysterols;    Eryptosis;    Oxidative stress;   

DOI  :  10.1159/000366322

学科分类：分子生物学，细胞生物学和基因

来源: S Karger AG

【 摘 要 】

Background/Aims Oxysterol activity on the erythrocyte (RBC) programmed cell death (eryptosis) had not been studied yet. Effects of an oxysterol mixture in hyper-cholesterolemic-relevant proportion, and of individual compounds, were investigated on RBCs from healthy humans. Methods Membrane phosphatidylserine (PS) externalization, calcium entry, ROS production, amino-phospholipid translocase (APLT) activity were evaluated by cytofluorimetric assays, cell volume from forward scatter. Prostaglandin PGE2 was measured by ELISA; GSH-adducts and lipoperoxides by spectrophotometry. Involvement of protein kinase C and caspase was investigated by inhibitors staurosporin, calphostin C, and Z-DEVD-FMK, respectively. Results Oxysterols caused PS externalization and cell shrinkage, associated with PGE2release, opening of PGE2-dependent calcium channels, ROS production, GSH depletion, membrane lipid oxidation. Addition of antioxidants prevented Ca²⁺ influx and eryptosis. Calcium removal prevented cell shrinkage, with small effect (-20%) on the PS exposure, whereas ROS generation was unaltered. Either in the presence or absence of calcium i) oxysterols inhibited APLT, ii) staurosporin, calphostin C, Z-DEVD-FMK blunted and iii) antioxidants fully prevented the oxysterol-induced PS externalization. Only 7-ketocholesterol and cholestan-3β,5α,6β-triol were individually active. Eryptosis was observed in RBCs isolated after ex vivo spiking of human whole blood with the oxysterol mixture. Conclusions Oxysterols induce an oxidative stress-dependent eryptosis, involving calcium-independent mechanisms. Eryptotic activity of oxysterols may be relevant in vivo.

【 授权许可】

CC BY-NC-ND