Jue Zhang, Jackie Chang, Vaya Chen, Mirza Ahmar Beg, Wenxin Huang, Lance Vick, Yaxin Wang, Heng Zhang, Erin Yttre, Ankan Gupta, Mark Castleberry, Ziyu Zhang, Wen Dai, Jieqing Zhu, Shan Song, Moua Yang, Ashley Kaye Brown, Zhen Xu, Yan-Qing Ma, Brian C Smith, Jacek Zielonka, James G Traylor, Cyrine Ben Dhaou, A Wayne Orr, Weiguo Cui, Yiliang Chen
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引用次数: 0
Abstract
Oxidized low-density lipoprotein (oxLDL) promotes proatherogenic phenotypes in macrophages, accelerating the progression of atherosclerosis. Our previous studies demonstrated that oxLDL binds to its receptor CD36, stimulating mitochondrial reactive oxygen species (mtROS), which are critical in atherosclerosis development. However, the mechanisms underlying mtROS induction and their effects on macrophage cellular functions remain poorly understood. Macrophages rely on phagocytosis to clear pathogens, apoptotic cells, or other particles, a process critical for tissue homeostasis. Dysregulated or excessive particle ingestion, a key step in phagocytosis, can lead to lipid overloading and foam cell formation, a hallmark of atherosclerosis. In this study, we showed that macrophages pretreated with oxLDL exhibit increased particle ingestion, a phagocytic response significantly attenuated in Cd36-null macrophages. Further investigations revealed that oxLDL-induced phagocytosis depends on mtROS, as their suppression inhibited the process. In vivo, atherosclerosis-prone Apoe-null mice on a high-fat diet exhibited increased mtROS levels and enhanced phagocytic activity in aortic foamy macrophages compared to those from chow diet-fed mice, supporting a role of mtROS in promoting lesional macrophage phagocytosis. Mechanistically, we identified a novel signaling pathway whereby oxLDL/CD36 interaction induces the translocation of the cytosolic enzyme pyruvate kinase muscle 2 (PKM2) to mitochondria. Disruption of PKM2 mitochondrial translocation using siRNA knockdown or a specific chemical inhibitor reduced mtROS production and attenuated oxLDL-induced phagocytosis. In conclusion, our findings reveal a novel oxLDL-CD36-PKM2 signaling axis that drives mtROS production and phagocytosis in atherogenic macrophages.
期刊介绍:
The Journal of Lipid Research (JLR) publishes original articles and reviews in the broadly defined area of biological lipids. We encourage the submission of manuscripts relating to lipids, including those addressing problems in biochemistry, molecular biology, structural biology, cell biology, genetics, molecular medicine, clinical medicine and metabolism. Major criteria for acceptance of articles are new insights into mechanisms of lipid function and metabolism and/or genes regulating lipid metabolism along with sound primary experimental data. Interpretation of the data is the authors’ responsibility, and speculation should be labeled as such. Manuscripts that provide new ways of purifying, identifying and quantifying lipids are invited for the Methods section of the Journal. JLR encourages contributions from investigators in all countries, but articles must be submitted in clear and concise English.