Inflammation Program, University of Iowa, Iowa City, IA, United States.
Molecular Medicine Program, University of Iowa, Iowa City, IA, United States.
Front Immunol. 2022 May 25;13:836754. doi: 10.3389/fimmu.2022.836754. eCollection 2022.
Neutrophils (polymorphonuclear leukocytes, PMNs) have a distinctively short lifespan, and tight regulation of cell survival and death is imperative for their normal function. We demonstrated previously that extends human neutrophil lifespan, which elicits an impaired immune response characterized by neutrophil dysfunction. Herein, we extended these studies, including our transcriptional profiling data, and employed Seahorse extracellular flux analysis, gas chromatography-mass spectrometry metabolite analysis, flow cytometry and several other biochemical approaches to demonstrate that the delayed apoptosis observed in -infected neutrophils is mediated, in part, by metabolic reprogramming. Specifically, we show that -infected neutrophils exhibited a unique metabolic signature characterized by increased glycolysis, glycolytic flux and glucose uptake, downregulation of the pentose phosphate pathway, and complex glycogen dynamics. Glucose uptake and glycolysis were essential for cell longevity, although glucose-6-phosphate translocation into the endoplasmic reticulum was not, and we identify depletion of glycogen as a potential trigger of apoptosis onset. In keeping with this, we also demonstrate that ablation of apoptosis with the pan-caspase inhibitor Q-VD-OPh was sufficient to profoundly increase glycolysis and glycogen stores in the absence of infection. Taken together, our data significantly advance understanding of neutrophil immunometabolism and its capacity to regulate cell lifespan.
中性粒细胞(多形核白细胞,PMN)的寿命极短,因此严格调控细胞的存活和死亡对于其正常功能至关重要。我们之前已经证明,能够延长人类中性粒细胞的寿命,这会导致免疫反应受损,表现为中性粒细胞功能障碍。在此基础上,我们扩展了这些研究,包括转录谱数据分析,并采用 Seahorse 细胞外通量分析、气相色谱-质谱代谢物分析、流式细胞术和其他几种生化方法,证明感染细胞中观察到的延迟凋亡部分是由代谢重编程介导的。具体而言,我们表明,感染的中性粒细胞表现出独特的代谢特征,表现为糖酵解、糖酵解通量和葡萄糖摄取增加,磷酸戊糖途径下调,以及复杂的糖原动态。葡萄糖摄取和糖酵解对于细胞寿命至关重要,尽管葡萄糖-6-磷酸向内质网的转运不是必需的,并且我们发现糖原耗竭可能是凋亡起始的潜在触发因素。与此一致,我们还证明,用广谱半胱天冬酶抑制剂 Q-VD-OPh 抑制凋亡足以在没有感染的情况下显著增加糖酵解和糖原储存。综上所述,我们的数据极大地提高了对中性粒细胞免疫代谢及其调节细胞寿命能力的理解。