Systemic Autoimmunity Branch, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD.
Biodata Mining and Discovery Section, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD; and.
J Immunol. 2022 Aug 15;209(4):772-782. doi: 10.4049/jimmunol.2200154.
Neutrophils are the most abundant leukocytes in human blood and are essential components of innate immunity. Until recently, neutrophils were considered homogeneous and transcriptionally inactive cells, but both concepts are being challenged. Single-cell RNA sequencing (scRNA-seq) offers an unbiased view of cells along a continuum of transcriptional states. However, the use of scRNA-seq to characterize neutrophils has proven technically difficult, explaining in part the paucity of published single-cell data on neutrophils. We have found that modifications to the data analysis pipeline, rather than to the existing scRNA-seq chemistries, can significantly increase the detection of human neutrophils in scRNA-seq. We have then applied a modified pipeline to the study of human peripheral blood neutrophils. Our findings indicate that circulating human neutrophils are transcriptionally heterogeneous cells, which can be classified into one of four transcriptional clusters that are reproducible among healthy human subjects. We demonstrate that peripheral blood neutrophils shift from relatively immature (Nh0) cells, through a transitional phenotype (Nh1), into one of two end points defined by either relative transcriptional inactivity (Nh2) or high expression of type I IFN-inducible genes (Nh3). Transitions among states are characterized by the expression of specific transcription factors. By simultaneously measuring surface proteins and intracellular transcripts at the single-cell level, we show that these transcriptional subsets are independent of the canonical surface proteins that are commonly used to define and characterize human neutrophils. These findings provide a new view of human neutrophil heterogeneity, with potential implications for the characterization of neutrophils in health and disease.
中性粒细胞是人类血液中最丰富的白细胞,是先天免疫的重要组成部分。直到最近,中性粒细胞还被认为是同质的和转录不活跃的细胞,但这两个概念都受到了挑战。单细胞 RNA 测序 (scRNA-seq) 提供了一个连续的转录状态的细胞的无偏视图。然而,使用 scRNA-seq 来描述中性粒细胞在技术上被证明是困难的,这部分解释了关于中性粒细胞的单细胞数据发表较少的原因。我们发现,对数据分析管道的修改,而不是对现有 scRNA-seq 化学物质的修改,可以显著增加 scRNA-seq 中人类中性粒细胞的检测。然后,我们将修改后的管道应用于人类外周血中性粒细胞的研究。我们的研究结果表明,循环中的人类中性粒细胞是转录异质性细胞,可以分为四个转录簇之一,在健康的人类受试者中具有可重复性。我们证明外周血中性粒细胞从相对不成熟的(Nh0)细胞,通过过渡表型(Nh1),转变为两种终末状态之一,这两种终末状态的特征是相对转录不活跃(Nh2)或 I 型干扰素诱导基因的高表达(Nh3)。状态之间的转变由特定转录因子的表达来表征。通过在单细胞水平上同时测量表面蛋白和细胞内转录本,我们表明这些转录亚群与通常用于定义和描述人类中性粒细胞的经典表面蛋白无关。这些发现为人类中性粒细胞异质性提供了新的视角,可能对健康和疾病中性粒细胞的特征具有潜在意义。