Abstract

Neutrophils fight with invading pathogens through various mechanisms including degranulation, phagocytosis, and the release of neutrophil extracellular traps (NETs). This study aimed to determine the impact of a synthetic formyl-peptide (FMLP) on human neutrophils in vitro, and to determine the role of mitoxantrone (MTX), a pharmacological blocker of mitochondrial Ca²⁺ Uniporter (MCU), on FMLP-induced alterations. Isolated neutrophils and a whole-blood preparation of neutrophils were pre-treated with MTX and then stimulated with FMLP. Field’s-stained smears and brightfield microscopy were employed for morphological characterization and quantification of neutrophils. The release of cell-free DNA (cfDNA) was also measured for determining neutrophil damage. Our data demonstrated degenerative changes in neutrophils and a greater cfDNA release upon stimulation with FMLP which was negatively associated with the presence of resting platelets in whole blood preparation. Interestingly, MTX pre-treatment significantly reduced FMLP-triggered neutrophil damage and cfDNA release. Metformin, a known inhibitor of NETs formation, also decreased the FMLP-induced changes in neutrophils. In addition to confirming the degenerative potential of FMLP, this study reveals a novel contribution of MCU in regulating FMLP-induced morphological alterations in human neutrophils.

中文翻译：

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米托蒽醌抑制 FMLP 诱导的人类中性粒细胞退行性变化

摘要

中性粒细胞通过脱粒、吞噬和释放中性粒细胞胞外陷阱 (NETs) 等各种机制与入侵的病原体作斗争。本研究旨在确定合成甲酰肽 (FMLP) 在体外对人类中性粒细胞的影响，并确定米托蒽醌 (MTX)（一种线粒体 Ca ²⁺的药理阻滞剂）的作用。Uniporter (MCU)，关于 FMLP 引起的改变。分离的中性粒细胞和中性粒细胞的全血制剂用 MTX 预处理，然后用 FMLP 刺激。现场染色涂片和明场显微镜用于中性粒细胞的形态学表征和量化。还测量了无细胞 DNA (cfDNA) 的释放以确定中性粒细胞损伤。我们的数据表明，中性粒细胞的退行性变化和 FMLP 刺激后 cfDNA 释放更多，这与全血制备中静息血小板的存在呈负相关。有趣的是，MTX 预处理显着减少了 FMLP 触发的中性粒细胞损伤和 cfDNA 释放。二甲双胍是一种已知的 NET 形成抑制剂，也降低了 FMLP 诱导的中性粒细胞变化。