Developmental Analysis of Bone Marrow Neutrophils Reveals Populations Specialized in Expansion, Trafficking, and Effector Functions

Abstract

Neutrophils are specialized innate cells that require constant replenishment from proliferative bone marrow (BM) precursors as a result of their short half-life. Although it is established that neutrophils are derived from the granulocyte-macrophage progenitor (GMP), the differentiation pathways from GMP to functional mature neutrophils are poorly defined. Using mass cytometry (CyTOF) and cell-cycle-based analysis, we identified three neutrophil subsets within the BM: a committed proliferative neutrophil precursor (preNeu) which differentiates into non-proliferating immature neutrophils and mature neutrophils. Transcriptomic profiling and functional analysis revealed that preNeu require the C/EBPε transcription factor for their generation from the GMP, and their proliferative program is substituted by a gain of migratory and effector function as they mature. preNeus expand under microbial and tumoral stress, and immature neutrophils are recruited to the periphery of tumor-bearing mice. In summary, our study identifies specialized BM granulocytic populations that ensure supply under homeostasis and stress responses.

Quantifying the Dynamics of Hematopoiesis by In Vivo IdU Pulse‐Chase, Mass Cytometry, and Mathematical Modeling

“…4A). This observation is also in accordance with a recently published study (18), where the authors reported decreased Ly-6G surface expression on proliferating neutrophils. Modeling the time-series by following the trajectory along the first principal component axis of the density distribution reveals two major peaks of differentiating populations.…”

“…In a recent study, Evrard et al . used in vivo administration of IdU to phenotypically and functionally distinguish proliferating and non-proliferating populations of immune cells (18). Here, we built on these two papers to perform IdU pulse-chase in live animals over multiple time points and to address the dynamics of differentiation.…”

“…Whereas IdU injection in mice has been used in microscopy imaging, for neogenesis (14), cell cycle analysis (15), and proliferation (16), its use in single-cell mass cytometry remains limited. IdU has been used in vitro on CyTOF measurements (17) to study cell cycle and to immunologically profile proliferating versus non-proliferating cells in the mouse bone marrow (18), however, it remains an untapped resource to study differentiation. Even so, studying hematopoiesis by an IdU pulse-chase experiment on the CyTOF carries with it significant qualitative advantages with respect to existing methods.…”

Neutrophil progenitor populations of rhesus macaques

“…This is primarily due to the earlier expression of CD11b, compared to the differentiation in rhesus macaques. Interestingly, in mice CD11b and CD32 are expressed on the cell surface throughout the entire granulopoiesis (31). While metamyelocytes can be found in populations I, II, and IIIa (Figure 3 L), the majority of them (63.5±3%) display III phenotype (Figure 3 M).…”

Expanding Neutrophil Horizons: New Concepts in Inflammation

“…Some recent studies have characterised these cells. A study of bone marrow neutrophils in mice using advanced cell cytometric techniques identified a dedicated pre-neutrophil population capable of differentiating into mature and immature neutrophils (based on CXCR2 status) [26]. This pre-neutrophil responded to systemic stressors of inflammation and malignancy by proliferating and providing a sustained neutrophil response in blood and tissues.…”