Erythroid lineage Jak2V617F expression promotes atherosclerosis through erythrophagocytosis and macrophage ferroptosis
Wenli Liu, … , Alan R. Tall, Nan Wang
Wenli Liu, … , Alan R. Tall, Nan Wang
Published May 19, 2022
Citation Information: J Clin Invest. 2022;132(13):e155724. https://doi.org/10.1172/JCI155724.
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Research Article Vascular biology

Erythroid lineage Jak2V617F expression promotes atherosclerosis through erythrophagocytosis and macrophage ferroptosis

Abstract

Elevated hematocrit is associated with cardiovascular risk; however, the causality and mechanisms are unclear. The JAK2V617F (Jak2VF) mutation increases cardiovascular risk in myeloproliferative disorders and in clonal hematopoiesis. Jak2VF mice with elevated WBCs, platelets, and RBCs display accelerated atherosclerosis and macrophage erythrophagocytosis. To investigate whether selective erythroid Jak2VF expression promotes atherosclerosis, we developed hyperlipidemic erythropoietin receptor Cre mice that express Jak2VF in the erythroid lineage (VFEpoR mice). VFEpoR mice without elevated blood cell counts showed increased atherosclerotic plaque necrosis, erythrophagocytosis, and ferroptosis. Selective induction of erythrocytosis with low-dose erythropoietin further exacerbated atherosclerosis with prominent ferroptosis, lipid peroxidation, and endothelial damage. VFEpoR RBCs had reduced antioxidant defenses and increased lipid hydroperoxides. Phagocytosis of human or murine WT or JAK2VF RBCs by WT macrophages induced ferroptosis, which was prevented by the ferroptosis inhibitor liproxstatin-1. Liproxstatin-1 reversed increased atherosclerosis, lipid peroxidation, ferroptosis, and endothelial damage in VFEpoR mice and in Jak2VF chimeric mice simulating clonal hematopoiesis, but had no impact in controls. Erythroid lineage Jak2VF expression led to qualitative and quantitative defects in RBCs that exacerbated atherosclerosis. Phagocytosis of RBCs by plaque macrophages promoted ferroptosis, suggesting a therapeutic target for reducing RBC-mediated cardiovascular risk.

Authors

Wenli Liu, Nataliya Östberg, Mustafa Yalcinkaya, Huijuan Dou, Kaori Endo-Umeda, Yang Tang, Xintong Hou, Tong Xiao, Trevor P. Fidler, Sandra Abramowicz, Yong-Guang Yang, Oliver Soehnlein, Alan R. Tall, Nan Wang

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Figure 4

Aortic endothelial permeability was increased in VFEpoR mice.

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Aortic endothelial permeability was increased in VFEpoR mice. Control an...
Control and VFEpoR mice were fed a Western diet (WD) and treated with LDLR ASO and EPO (3 times per week) for 6 or 12 weeks. (A) FITC dextran (green, 70 kDa) and nuclei (blue, DAPI) in aortic root cross-section, which were probed for endothelial permeability after 12 weeks of a WD. Scale bar: 50 μL. (B) Aortic arch and descending aorta were probed for endothelial permeability using Evans blue intravital staining after 6 or 12 weeks of a WD. The bar graph shows quantification of Evans blue extravasation normalized by the tissue weight. (C) En face scanning electron microscopy showing the luminal surface of the aortic arches; the bar graph shows numbers of the field that had RBC attachment or no RBC attachment (n = 3 per group); χ2 test. (D) Ldlr–/– mice were fed a WD for 2 weeks and then transfused with packed and PKH26-labeled 80–100 μL control or VFEpoR RBCs once per week for another 5 weeks, in total 7 weeks of WD. Representative 3D-rendered image from RBC-transfused mice aortic root lesions staining of macrophages (anti-Mac2, green) and RBCs (PKH26, red), and quantification of infiltrated RBC counts and erythrophagocytic macrophage counts in the lesions. Size: 332.80 μm × 332.80 μm × 7.50 μm. Calibration: XY:0.65 μm, Z:1.50 μm. Unpaired 2-tailed t test. *P < 0.05, **P < 0.01.