Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz-Center for Infection Research (HZI), Wuerzburg, Germany (E.V., A.-E.S.).
Comprehensive Heart Failure Center Wuerzburg (G.R., L.K., A.-P.A.-L., V.A.N., D.J.J.S., C.C.), University Hospital Wuerzburg, Germany.
Circ Res. 2020 Oct 9;127(9):e232-e249. doi: 10.1161/CIRCRESAHA.120.317200. Epub 2020 Aug 19.
After myocardial infarction, neutrophils rapidly and massively infiltrate the heart, where they promote both tissue healing and damage.
To characterize the dynamics of circulating and cardiac neutrophil diversity after infarction.
We employed single-cell transcriptomics combined with cell surface epitope detection by sequencing to investigate temporal neutrophil diversity in the blood and heart after murine myocardial infarction. At day 1, 3, and 5 after infarction, cardiac Ly6G (lymphocyte antigen 6G) neutrophils could be delineated into 6 distinct clusters with specific time-dependent patterning and proportions. At day 1, neutrophils were characterized by a gene expression profile proximal to bone marrow neutrophils (, , ), and putative activity of transcriptional regulators involved in hypoxic response () and emergency granulopoiesis (). At 3 and 5 days, 2 major subsets of (enriched for eg, and ) and () neutrophils were found. Cellular indexing of transcriptomes and epitopes by sequencing (CITE-seq) analysis in blood and heart revealed that while circulating neutrophils undergo a process of aging characterized by loss of surface CD62L and upregulation of , heart infiltrating neutrophils acquired a unique SiglecF signature. SiglecF neutrophils were absent from the bone marrow and spleen, indicating local acquisition of the SiglecF signature. Reducing the influx of blood neutrophils by anti-Ly6G treatment increased proportions of cardiac SiglecF neutrophils, suggesting accumulation of locally aged neutrophils. Computational analysis of ligand/receptor interactions revealed putative pathways mediating neutrophil to macrophage communication in the myocardium. Finally, SiglecF neutrophils were also found in atherosclerotic vessels, revealing that they arise across distinct contexts of cardiovascular inflammation.
Altogether, our data provide a time-resolved census of neutrophil diversity and gene expression dynamics in the mouse blood and ischemic heart at the single-cell level, and reveal a process of local tissue specification of neutrophils in the ischemic heart characterized by the acquisition of a SiglecF signature.
心肌梗死后，大量中性粒细胞迅速浸润心脏，促进组织修复和损伤。
描述梗死后循环和心脏中性粒细胞多样性的动态变化。
我们采用单细胞转录组学结合细胞表面表位测序检测，研究了小鼠心肌梗死后血液和心脏中性粒细胞的时间多样性。在梗死后 1、3 和 5 天，心脏 Ly6G（淋巴细胞抗原 6G）中性粒细胞可分为 6 个不同的簇，具有特定的时间依赖性模式和比例。在第 1 天，中性粒细胞的基因表达谱与骨髓中性粒细胞（，，）接近，并且假定参与缺氧反应（）和紧急粒细胞生成（）的转录调节因子的活性（）。在 3 天和 5 天，发现了 2 种主要的 （富含 eg，和）和 （）中性粒细胞亚群。血液和心脏的转录组和表位细胞索引测序（CITE-seq）分析表明，虽然循环中性粒细胞经历了一个特征为表面 CD62L 丢失和上调的衰老过程，而心脏浸润的中性粒细胞获得了独特的 SiglecF 特征。SiglecF 中性粒细胞不存在于骨髓和脾脏中，表明 SiglecF 特征是在局部获得的。通过抗 Ly6G 治疗减少血液中性粒细胞的流入增加了心脏 SiglecF 中性粒细胞的比例，提示局部积累了老化的中性粒细胞。对配体/受体相互作用的计算分析揭示了介导心肌中性粒细胞与巨噬细胞通讯的潜在途径。最后，还在动脉粥样硬化血管中发现了 SiglecF 中性粒细胞，表明它们在不同的心血管炎症背景下出现。
总之，我们的数据提供了在单细胞水平上，在小鼠血液和缺血心脏中中性粒细胞多样性和基因表达动力学的时间分辨率普查，并揭示了缺血心脏中中性粒细胞的局部组织特化过程，其特征是获得 SiglecF 特征。
