SIRT1/FOXO1 axis regulates mitophagy and glycolytic metabolism in LPS-stimulated macrophages: implications for neuroinflammation

To investigate the regulatory role and molecular mechanisms of the SIRT1-FOXO1 signaling axis in mitophagy, glycolytic metabolism, and inflammatory responses within a lipopolysaccharide (LPS)-induced macrophage inflammation model. An in vitro inflammatory model was established by treating RAW264.7 macrophages with LPS. Mitochondrial membrane potential was assessed using the JC-1 probe. Western Blotting and immunofluorescence were used to analyze the expression of autophagy-related proteins. Inflammatory cytokines and the oxidative stress marker Malondialdehyde (MDA) were measured by ELISA, respectively. Furthermore, lactate production, glucose uptake, ATP levels, and the expression of glycolysis-related proteins were evaluated. Silencing SIRT1 or overexpressing FOXO1 induced the excessive expression of the key mitophagy proteins PINK1 and Parkin, leading to mitochondrial membrane potential dissipation and increased release of inflammatory factors (TNF-α, IL-1β) and MDA. These changes were accompanied by increased glucose uptake, lactate production, elevated ATP levels, upregulation of key glycolysis-related proteins, and acidification of the cellular microenvironment. Rapamycin further enhanced, whereas 3-MA attenuated, the phenotypes triggered by SIRT1-FOXO1 axis imbalance. SIRT1 negatively regulates FOXO1, thereby preventing excessive activation of mitophagy and glycolytic metabolic shift. This action helps maintain mitochondrial functional homeostasis and effectively inhibits the inflammatory response. These findings reveal the crucial negative regulatory role of the SIRT1-FOXO1 axis in LPS-induced macrophage inflammation, suggesting that this pathway may represent a potential therapeutic target for neuroinflammatory diseases such as ischemic stroke.