High Mobility Group B-1 (HMGB-1) Promotes Apoptosis of Macrophage-Derived Foam Cells by Inducing Endoplasmic Reticulum Stress

Cellular Physiology and Biochemistry

Han Wu¹ 

关键词: High mobility group B-1;    Foam cell formation;    Apoptosis;    Endoplasmic reticulum stress;   

DOI  :  10.1159/000491970

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 High mobility group B-1 (HMGB-1)-induced endoplasmic reticulum stress (ERS) has been implicated in inflammation and dendritic cell maturation. C/EBP-homologous protein (CHOP) is a vital component of ERS and apoptosis and plays a critical role in atherosclerosis. However, only a little information is available about the role of HMGB-1 in foam cell formation. Thus, the role of HMGB-1-induced ERS/CHOP pathway in apoptosis and formation of macrophage-derived foam cells is investigated. Methods RAW264.7 cells were treated with oxidized low-density lipoprotein (oxLDL) in the absence and/or presence of HMGB-1, N-acetylcysteine (NAC, an antioxidant), glycyrrhizin (Gly, an HMGB-1 inhibitor), tunicamycin (TM, an ERS inducer), and 4-phenylbutyrate (4-PBA, an ERS inhibitor). Reactive oxygen species (ROS) production was examined by dihydroethidium (DHE) staining. Oil Red O staining, intracellular total cholesterol assay, and Dil-oxLDL uptake assay evaluated the accumulation of lipids in macrophages. Cell apoptosis was measured by flow cytometry and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining. Western blot detected the expression of HMGB-1/ERS/CHOP pathway. Results oxLDL induced HMGB-1 translocation and secretion in a dose- and time-dependent manner, which was inhibited by NAC. oxLDL-induced lipid accumulation in macrophages was promoted synergistically by HMGB-1 that was attenuated by Gly. Moreover, TM synergized with oxLDL induced lipid accumulation and apoptosis of macrophages; however, 4-PBA alleviated the oxLDL-induced apoptotic foam cells. Additionally, the inhibition of ERS with 4-PBA suppressed the expression of HMGB-1-induced CHOP. Conclusions OxLDL triggered HMGB-1 secretion in macrophages via oxidative stress. Furthermore, HMGB-1 promoted the formation and apoptosis of macrophage-derived foam cells via activation of ERS/CHOP pathway.

【 授权许可】

CC BY-NC-ND