Integrated Proteomics and Metabolomics Analyses Reveal That Phosphatidylethanolamine Reprograms Macrophage...

Phospholipids are key regulators of immune metabolism, yet their specific influence on macrophage function remains incompletely defined. We investigated how phosphatidylethanolamine (PE) species with distinct acyl chains (PE18:0/22:6 and PE18:0/20:4) modulate RAW264.7 macrophages under resting and LPS-stimulated conditions using LC-MS/MS-based proteomics and metabolomics, followed by qPCR validation. LPS elicited a robust M1-like phenotype with strong upregulation of Ptgs2, Nos2, Nfkb1, and Nfkb2. PE supplementation alone did not induce a classical pro-inflammatory profile but significantly remodeled protein expression, enhancing antioxidant defenses, including catalase, Hmox1 and Prdx1. In the context of LPS activation, PE selectively attenuated inflammatory signaling by downregulating Nfkb1, Nfkb2, and Ptgs2 while further enhancing proteins linked to oxidative stress response (Prdx1 and Hmox1) and lipid metabolism (CD36 and Abcc1). qPCR corroborated these effects: both PE species reduced LPS-induced Il1b and Ptgs2 mRNA levels while increasing Prdx1, Hmox1, and Cd36 transcription. Metabolomics converged with these findings, indicating reinforced glutathione metabolism and context-dependent shifts in purine and amino-acid pathways consistent with a restrained inflammatory phenotype. Collectively, native PE species reprogram macrophage immunometabolism, mitigating LPS-driven inflammation while strengthening Nrf2-mediated antioxidant and immune-supportive pathways.