Center for Experimental and Molecular Medicine, University of Amsterdam, 1105 AZ Amsterdam, the Netherlands;
Amsterdam Infection and Immunity Institute, 1105 AZ Amsterdam, the Netherlands.
J Immunol. 2021 Feb 15;206(4):827-838. doi: 10.4049/jimmunol.2000702. Epub 2021 Jan 6.
Circulating nonadherent monocytes can migrate to extravascular sites by a process that involves adherence. Alterations in intracellular metabolism shape the immunological phenotype of phagocytes upon activation. To determine the effect of adherence on their metabolic and functional response human monocytes were stimulated with LPS under nonadherent and adherent conditions. Adherent monocytes (relative to nonadherent monocytes) produced less TNF and IL-1β (proinflammatory) and more IL-10 (anti-inflammatory) upon LPS stimulation and had an increased capacity to phagocytose and produce reactive oxygen species. RNA sequencing analysis confirmed that adherence modified the LPS-induced response of monocytes, reducing expression of proinflammatory genes involved in TLR signaling and increasing induction of genes involved in pathogen elimination. Adherence resulted in an increased glycolytic response as indicated by lactate release, gene set enrichment, and [C]-glucose flux analysis. To determine the role of glycolysis in LPS-induced immune responses, this pathway was inhibited by glucose deprivation or the glucose analogue 2-deoxy-d-glucose (2DG). Although both interventions equally inhibited glycolysis, only 2DG influenced monocyte functions, inhibiting expression of genes involved in TLR signaling and pathogen elimination, as well as cytokine release. 2DG, but not glucose deprivation, reduced expression of genes involved in oxidative phosphorylation. Inhibition of oxidative phosphorylation affected TNF and IL-10 release in a similar way as 2DG. Collectively, these data suggest that adherence may modify the metabolic and immunological profile of monocytes and that inhibition of glycolysis and oxidative phosphorylation, but not inhibition of glycolysis alone, has a profound effect on immune functions of monocytes exposed to LPS.
循环非黏附性单核细胞可以通过黏附过程迁移到血管外部位。细胞内代谢的改变塑造了吞噬细胞在激活后的免疫表型。为了确定黏附对其代谢和功能反应的影响，我们在非黏附性和黏附性条件下用 LPS 刺激人单核细胞。与非黏附性单核细胞相比，黏附性单核细胞（adherent monocytes）在 LPS 刺激下产生的 TNF 和 IL-1β（促炎）较少，而产生的 IL-10（抗炎）较多，吞噬和产生活性氧的能力也增加。RNA 测序分析证实，黏附改变了单核细胞对 LPS 的反应，降低了参与 TLR 信号的促炎基因的表达，并增加了参与病原体清除的基因的诱导。黏附导致糖酵解反应增加，如乳酸盐释放、基因集富集和 [C]-葡萄糖通量分析所示。为了确定糖酵解在 LPS 诱导的免疫反应中的作用，我们通过葡萄糖剥夺或葡萄糖类似物 2-脱氧-D-葡萄糖（2DG）抑制该途径。尽管这两种干预措施都能同等地抑制糖酵解，但只有 2DG 影响单核细胞的功能，抑制参与 TLR 信号和病原体清除的基因的表达以及细胞因子的释放。2DG，但不是葡萄糖剥夺，降低了参与氧化磷酸化的基因的表达。氧化磷酸化的抑制以与 2DG 相似的方式影响 TNF 和 IL-10 的释放。总的来说，这些数据表明，黏附可能改变单核细胞的代谢和免疫特征，并且抑制糖酵解和氧化磷酸化，而不仅仅是抑制糖酵解，对暴露于 LPS 的单核细胞的免疫功能有深远影响。
