Integrated Proteomics and Metabolomics Analyses Reveal That Phosphatidylethanolamine Reprograms Macrophage Immunometabolism and Attenuates LPS-Driven Inflammation

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.