Effects of Oxidative Stress and Interleukin-1β on β2-Glycoprotein I Gene Regulation

• Main Authors: Pei-Hsin Ke, 柯佩馨
• Other Authors: An-Na Chiang
• Format: Others
• Language: zh-TW
• Published: 2008
• Online Access: http://ndltd.ncl.edu.tw/handle/47203807653821021867

碩士 === 國立陽明大學 === 生化暨分子生物研究所 === 96 === β2-Glycoprotein I (β2-GPI) is a plasma glycoprotein mainly synthesized in the liver. Several lines of evidence suggest that β2-GPI may implicate in the development of atherosclerosis, though the regulation of β2-GPI gene expression have not been clarified yet. The aim of this study was to investigate whether oxidative stress and inflammatory cytokines regulate β2-GPI expression in HepG2 cells and vascular smooth muscle cells, respectively. The protein and mRNA levels of β2-GPI were up-regulated by hydrogen peroxide (H2O2) and interleukin-1β (IL-1β) in a dose-dependent manner in HepG2 and human coronary artery smooth muscle cells (HCASMCs). AP-1 and NF-κB are well-known transcription factors involved in redox-signaling pathways and inflammation reactions. The 5'-flanking regions containing AP-1 and NF-κB cis-elements upstream of β2-GPI gene were cloned into luciferase plasmids. The promoter activity of β2-GPI was analyzed by transient transfection and luciferase assay in Huh7 cells. Four putative AP-1 cis-elements within the region spanning from -2.2 to -2.1 kb were found to up-regulate β2-GPI promoter activity under H2O2 treatment. Electrophoretic mobility shift assay (EMSA) showed that the interaction of AP-1 with its response elements upstream of β2-GPI gene was enhanced in the nuclear of HepG2 cells treated with H2O2. In parallel experiments, the promoter activity of β2-GPI gene which contains NF-κB cis-element was raised by IL-1β�ntreatment. IL-1β increased the interaction between nuclear protein and the NF-κB cis-element upstream of β2-GPI gene as well. These findings imply the involvement of H2O2 and IL-1β�nin β2-GPI gene regulation and extend insights into the regulatory region of β2-GPI promoter region.