van Linge Christine C A, Michels Erik H A, Pereverzeva Liza, de Beer Regina, Klarenbeek Augustijn M, Schomakers Bauke V, van Weeghel Michel, Houtkooper Riekelt H, Wiersinga W Joost, Bonta Peter I, Annema Jouke T, van der Poll Tom, de Vos Alex F
Center for Infection and Molecular Medicine, Amsterdam University Medical Center, University of Amsterdam, Amsterdam 1105 AZ, the Netherlands.
Amsterdam institute for Immunology and Infectious diseases, Amsterdam 1105 AZ, the Netherlands.
Clin Exp Immunol. 2025 Jan 21;219(1). doi: 10.1093/cei/uxaf028.
Alveolar macrophages (AMs) play an essential role in maintaining homeostasis in the lung and in innate immunity for host defense. To fuel inflammatory responses, AMs do not rely on glycolysis, but require oxidative phosphorylation. However, which nutrients AMs use to fuel their energy demand during inflammatory responses, is still unknown. The present study aimed to determine the contribution of three key metabolic pathways; fatty acid oxidation, glutaminolysis, and glycogenolysis, to the inflammatory response of AMs.
Primary AMs were isolated from healthy human volunteers and stimulated with lipopolysaccharide (LPS). After 24 hours, cells were subjected to analyses of metabolic flux, expression of genes involved in these metabolic pathways, and inflammatory cytokine secretion in the presence of metabolic inhibitors.
The results of our study show that human AMs display expression of genes involved in fatty acid and glutamine metabolism and are capable of metabolizing oleic acid and glutamine during homeostasis, but do not use these metabolites to fuel the production of inflammatory cytokines. We demonstrate that AMs, while residing in a glucose-deprived environment, contain glycogen and use glycogenolysis to fuel inflammatory cytokine secretion, as reflected by reduced TNF, IL-1β and IL-6 levels in supernatant of LPS-stimulated AMs treated with the glycogenolysis inhibitor CP316819. Moreover, AMs display marked expression of genes involved in glycogenesis, including FBP1 and GYS.
Taken together, these results indicate that primary human AMs are equipped to use different nutrients to fuel their metabolic demands. Moreover, our findings suggest that glycogenolysis is critical for the inflammatory response of AMs.
肺泡巨噬细胞（AMs）在维持肺部内环境稳定以及宿主防御的固有免疫中发挥着至关重要的作用。为了促进炎症反应，AMs并不依赖糖酵解，而是需要氧化磷酸化。然而，在炎症反应期间AMs利用哪些营养物质来满足其能量需求仍不清楚。本研究旨在确定三种关键代谢途径；脂肪酸氧化、谷氨酰胺分解和糖原分解，对AMs炎症反应的贡献。
从健康人类志愿者中分离出原代AMs，并用脂多糖（LPS）进行刺激。24小时后，在存在代谢抑制剂的情况下，对细胞进行代谢通量分析、参与这些代谢途径的基因表达分析以及炎症细胞因子分泌分析。
我们的研究结果表明，人类AMs显示出参与脂肪酸和谷氨酰胺代谢的基因表达，并且在稳态期间能够代谢油酸和谷氨酰胺，但不利用这些代谢物来促进炎症细胞因子的产生。我们证明，虽然AMs处于葡萄糖缺乏的环境中，但它们含有糖原并利用糖原分解来促进炎症细胞因子的分泌，这一点通过用糖原分解抑制剂CP316819处理的LPS刺激的AMs上清液中TNF、IL-1β和IL-6水平的降低得到反映。此外，AMs显示出参与糖原合成的基因的显著表达，包括FBP1和GYS。
综上所述，这些结果表明原代人类AMs具备利用不同营养物质来满足其代谢需求的能力。此外，我们的研究结果表明糖原分解对AMs的炎症反应至关重要。
