Neutrophils, an essential innate immune cell type with a short lifespan, rely on continuous replenishment from bone marrow (BM) precursors. Although it is established that neutrophils are derived from the granulocyte-macrophage progenitor (GMP), the molecular regulators involved in the differentiation process remain poorly understood. Here we developed a random forest-based machine-learning pipeline, NeuRGI (Neutrophil Regulatory Gene Identifier), which utilized Positive-Unlabeled Learning (PU-learning) and neural network-based in silico gene knockout to identify neutrophil regulators. We interrogated features including gene expression dynamics, physiological characteristics, pathological relatedness, and gene conservation for the model training. Our identified pipeline leads to identifying Mitogen-Activated Protein Kinase-4 (MAP4K4) as a novel neutrophil differentiation regulator. The loss of MAP4K4 in hematopoietic stem cells and progenitors in mice induced neutropenia and impeded the differentiation of neutrophils in the bone marrow. By modulating the phosphorylation level of proteins involved in cell apoptosis, such as STAT5A, MAP4K4 delicately regulates cell apoptosis during the process of neutrophil differentiation. Our work presents a novel regulatory mechanism in neutrophil differentiation and provides a robust prediction model that can be applied to other cellular differentiation processes.
Copyright: © 2025 Wang et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Irradiation with X-rays has been widely utilized in the clinical treatment of solid tumors and certain hematopoietic malignancies. However, this method fails to completely distinguish between malignant and normal cells. Prolonged or repeated exposure to radiation, whether due to occupational hazards or therapeutical interventions, can cause damage to normal tissues, particularly impacting the hematopoietic system. Therefore, it is important to investigate the effects of total body irradiation on the hematopoietic system of mice and to compare the inhibitory effects of various doses of irradiation on this system. In this study, we primarily employed flow cytometry to analyze mature lineage cells in the peripheral blood, as well as immature hematopoietic stem and progenitor cells (HSPCs) in the bone marrow and spleen. Additionally, we evaluated the multilineage differentiation capacity of HSPCs through colony-forming cell assays. Our results indicated that peripheral B and T cells demonstrated increased sensitivity to irradiation, with significant cell death observed 1-day post-irradiation. Common lymphoid progenitor cells exhibited greater radiotolerance compared to other progenitor cell types, enabling them to maintain a certain population even at elevated doses. Moreover, notable differences were observed between intramedullary and extramedullary hematopoietic stem cells and common lymphoid progenitor cells regarding the extent of damage and recovery rate following irradiation. The multilineage differentiation capacity of HSPCs was also compromised during radiation exposure. In conclusion, different types of mature blood cells, along with immature HSPCs, exhibited varying degrees of sensitivity and tolerance to irradiation, resulting in distinct alterations in cell percentages and numbers.
Copyright © 2024 The Authors. Published by Wolters Kluwer Health Inc., on behalf of the Chinese Medical Association (CMA) and Institute of Hematology, Chinese Academy of Medical Sciences & Peking Union Medical College (IHCAMS).

Colchicine is a broad-acting anti-inflammatory agent that has attracted interest for repurposing in atherosclerotic cardiovascular disease. Here, we studied its ability at a human equivalent dose of 0.5 mg/day to modify plaque formation and composition in murine atherosclerosis and investigated its actions on macrophage responses to atherogenic stimuli in vitro. In atherosclerosis induced by high-cholesterol diet, Apoe-/- mice treated with colchicine had 50% reduction in aortic oil Red O+ plaque area compared to saline control (p = .001) and lower oil Red O+ staining of aortic sinus lesions (p = .03). In vitro, addition of 10 nM colchicine inhibited foam cell formation from murine and human macrophages after treatment with oxidized LDL (ox-LDL). Mechanistically, colchicine downregulated glycosylation and surface expression of the ox-LDL uptake receptor, CD36, and reduced CD36+ staining in aortic sinus plaques. It also decreased macrophage uptake of cholesterol crystals, resulting in lower intracellular lysosomal activity, inhibition of the NLRP3 inflammasome, and reduced secretion of IL-1β and IL-18. Colchicine's anti-atherosclerotic actions were accentuated in a mouse model of unstable plaque induced by carotid artery tandem stenosis surgery, where it decreased lesion size by 48% (p = .01), reduced lipid (p = .006) and necrotic core area (p = .007), increased collagen content and cap-to-necrotic core ratio (p = .05), and attenuated plaque neutrophil extracellular traps (p < .001). At low dose, colchicine's effects were not accompanied by the evidence of microtubule depolymerization. Together, these results show that colchicine exerts anti-atherosclerotic and plaque-stabilizing effects at low dose by inhibiting foam cell formation and cholesterol crystal-induced inflammation. This provides a new framework to support its repurposing for atherosclerotic cardiovascular disease.
© 2023 Federation of American Societies for Experimental Biology.