Laboratory of Experimental Hematology, Institute of Zoology and Biomedical Research, Jagiellonian University, 30-387 Krakow, Poland.
Int J Mol Sci. 2021 Jul 19;22(14):7718. doi: 10.3390/ijms22147718.
Obesity manifests itself with low-grade chronic inflammation that shapes immune responses during infection. Albeit obese individuals are at risk of higher mortality due to comorbidities, they are better protected from systemic inflammation. Recently, we showed that in the vasculature of obese mice kept on high-fat diet (HFD), neutrophils produce less neutrophil extracellular traps (NETs) than in lean controls (normal diet, ND). NETs are used by neutrophils to counteract severe infection, but they also cause collateral damage. Hardly anything is known about metabolic requirements for their formation, especially in the context of obesity and/or sepsis. Thus, we aimed to study the immunometabolism of NET formation by application of ex vivo neutrophil analyses (Seahorse analyzer, selective inhibitors, confocal imaging) and intravital microscopy. The obtained data show that glycolysis and/or pentose phosphate pathway are involved in NETs release by ND neutrophils in both physiological and inflammatory conditions. In contrast, such cells of septic HFD mice utilize these routes only to spontaneously cast NETs, while after secondary ex vivo activation they exhibit so called "exhausted phenotype", which manifests itself in diminished NET release despite high glycolytic potential and flexibility to oxidize fatty acids. Moreover, impact of ATP synthase inhibition on NET formation is revealed. Overall, the study shows that the neutrophil potential to cast NETs depends on both the metabolic and inflammatory state of the individual.
肥胖表现为低度慢性炎症，这种炎症会影响感染期间的免疫反应。尽管肥胖个体由于合并症而面临更高的死亡率，但他们受到全身炎症的保护更好。最近，我们发现，在高脂肪饮食（HFD）饲养的肥胖小鼠的血管中，中性粒细胞产生的中性粒细胞胞外陷阱（NETs）比瘦对照组（正常饮食，ND）少。NETs 被中性粒细胞用来对抗严重感染，但它们也会造成附带损伤。关于它们形成的代谢需求，尤其是在肥胖和/或败血症的情况下，几乎没有什么是已知的。因此，我们旨在通过应用体外中性粒细胞分析（ Seahorse 分析仪、选择性抑制剂、共聚焦成像）和活体显微镜来研究 NET 形成的免疫代谢。获得的数据表明，在生理和炎症条件下，ND 中性粒细胞的糖酵解和/或戊糖磷酸途径参与 NETs 的释放。相比之下，在败血症的 HFD 小鼠中，这些细胞仅利用这些途径来自发地形成 NETs，而在体外二次激活后，它们表现出所谓的“耗尽表型”，尽管具有高糖酵解潜力和氧化脂肪酸的灵活性，但 NETs 的释放减少。此外，还揭示了 ATP 合酶抑制对 NET 形成的影响。总的来说，这项研究表明，中性粒细胞形成 NETs 的能力取决于个体的代谢和炎症状态。
