scRNA-seq/CITE-seq analysis of aortic CD45+ cells from mice expressing Jak2V617F mutation in myeloid cells

JAK2V617F mutation is associated with an increased risk for athero-thrombotic cardiovascular disease, but its role in aortic disease development and complications remains unknown. In a cohort of patients with myeloproliferative neoplasm, JAK2V617F mutation was identified as an independent risk factor for dilation of both the ascending and descending thoracic aorta. Using single-cell RNA-seq, complementary genetically-modified mouse models, as well as pharmacological approaches, we found that JAK2V617F mutation was associated with a pathogenic pro-inflammatory phenotype of perivascular tissue-resident macrophages, which promoted deleterious aortic wall remodeling at early stages, and dissecting aneurysm through the recruitment of circulating monocytes at later stages. Finally, genetic manipulation of tissue-resident macrophages, or treatment with a Jak2 inhibitor, ruxolitinib, mitigated aortic wall inflammation and reduced aortic dilation and rupture. Overall, JAK2V617F mutation drives vascular resident macrophages toward a pathogenic phenotype and promotes dissecting aortic aneurysm. Aortic CD45+ cells were sorted from control mice (Jak2-WT; n=5) and mice with a myeloid specific expression of mutated JAK2 variant Jak2V617F (Jak2-V617F-MyC; n=5) and processed for scRNA-seq with CITE-seqJAK2V617F突变（JAK2V617F mutation）与动脉粥样硬化血栓性心血管疾病的发病风险升高密切相关，但其在主动脉疾病发生及并发症进程中的作用仍未明确。在一项针对骨髓增殖性肿瘤（myeloproliferative neoplasm）患者的队列研究中，JAK2V617F突变被证实为升主动脉与降主动脉扩张的独立危险因素。本研究借助单细胞RNA测序（single-cell RNA-seq）、互补型基因工程小鼠模型以及药理学干预手段，发现JAK2V617F突变可诱导血管周围组织驻留巨噬细胞呈现致病性促炎表型：该表型在疾病早期即可介导有害的主动脉壁重构，并在后期通过招募循环单核细胞促进主动脉夹层动脉瘤形成。进一步研究显示，对组织驻留巨噬细胞进行基因修饰干预，或使用Jak2抑制剂芦可替尼（ruxolitinib）治疗，均可有效减轻主动脉壁炎症反应，缩小主动脉扩张程度并降低破裂风险。综上，JAK2V617F突变可驱使血管驻留巨噬细胞向致病性表型转化，并最终促进主动脉夹层动脉瘤的发生发展。研究人员分别从对照组小鼠（Jak2-WT；n=5）以及髓系特异性表达突变型JAK2变体Jak2V617F的小鼠（Jak2-V617F-MyC；n=5）中分选主动脉CD45+细胞，并通过CITE-seq技术完成单细胞RNA测序分析。