Li Shan, Gao Guangdong, Wu Fuyun, Liu Dan, Zhao Hongyan, Ke Jing, Liu Ying, Li Fei, Li Jian, Chen Zongyun, Tang Zhiming, Bai Lei, Zhang Jinxuan, Zheng Wei, Chen Xin
Department of Integrated Medicine, Affiliated Dongfeng Hospital, Hubei University of Medicine, Shiyan, China.
Department of biochemistry, Institute of Basic Medical Sciences, Hubei University of Medicine, Shiyan, China.
J Cell Biochem. 2019 May;120(5):7689-7700. doi: 10.1002/jcb.28043. Epub 2018 Nov 13.
Advanced glycation end-product is a modified form of low-density lipoprotein (AGE-LDL) and accelerates atherosclerosis through undefined mechanisms. Programmed cell death protein 4 (PDCD4), a transcriptional regulator, plays an important role in the regulation of autophagy. The aim of the present study was to investigate the role of PDCD4 involved in AGE-LDL-induced foam cell formation.
The characterization of AGE-LDL was measured by the thiobarbituric assay and agarose gel electrophoresis in vitro. RAW264.7, THP-1 cell line and primary peritoneal macrophages of mice were transfected with shPDCD4 plasmid AGE-LDL-induced foam cell formation was stained by Oil Red, and the levels of autophagy and apoptosis were determined by Western blot analysis. Autophagosome was observed with immunofluorescence microscopy. Mitochondrial membrane potential and autophagic flux were assessed by flow cytometry.
AGE modification resulted in significant reduction of absorbance shown by thiobarbituric assay and augmentation of electrophoresis mobility. Further studies suggest that macrophages exposed AGE-LDL triggered autophagy in the early stage of foam cell formation. PDCD4 deficiency enhanced lipoautophagy but inhibited apoptosis and mitochondria dysfunction. Previous studies have been reported that autophagy is an adaptive response might prevent lesional macrophage apoptosis. In our study, we found PDCD4 deficiency attenuated apoptosis and AGE-LDL-induced foam cell formation relied on increased autophagy.
Our data revealed that PDCD4 deficiency can facilitate autophagy and benefit for AGE-LDL-induced foam cell formation.
晚期糖基化终产物是低密度脂蛋白的一种修饰形式（AGE-LDL），其通过未知机制加速动脉粥样硬化。程序性细胞死亡蛋白4（PDCD4）作为一种转录调节因子，在自噬调节中发挥重要作用。本研究旨在探讨PDCD4在AGE-LDL诱导的泡沫细胞形成中的作用。
体外通过硫代巴比妥酸法和琼脂糖凝胶电泳对AGE-LDL进行特性分析。用shPDCD4质粒转染RAW264.7、THP-1细胞系和小鼠原代腹腔巨噬细胞，用油红染色AGE-LDL诱导的泡沫细胞形成，通过蛋白质免疫印迹分析确定自噬和凋亡水平。用免疫荧光显微镜观察自噬体。通过流式细胞术评估线粒体膜电位和自噬通量。
AGE修饰导致硫代巴比妥酸法显示的吸光度显著降低以及电泳迁移率增加。进一步研究表明，暴露于AGE-LDL的巨噬细胞在泡沫细胞形成的早期触发自噬。PDCD4缺乏增强了脂质自噬，但抑制了凋亡和线粒体功能障碍。先前的研究报道自噬是一种适应性反应，可能会阻止病变巨噬细胞凋亡。在我们的研究中，我们发现PDCD4缺乏减轻了凋亡，且AGE-LDL诱导的泡沫细胞形成依赖于自噬增加。
我们的数据表明，PDCD4缺乏可促进自噬，并有利于AGE-LDL诱导的泡沫细胞形成。
