Phosphatidylethanolamine exerts anti-inflammatory action by regulating mitochondrial function in macrophages of large yellow croaker (Larimichthys crocea)

Phosphatidylethanolamine (PE) is a ubiquitous bioactive lipid in cells, which participates in regulating many metabolic processes. Exogenous PE has been reported to play a positive regulatory role in macrophage inflammatory responses. However, the molecular mechanisms of PE in regulating macrophage inflammation are not completely understood. In the present study, transcriptomic analysis of PE-stimulated macrophages of large yellow croaker revealed that differentially expressed genes were mainly active in cellular components of the mitochondrial respiratory chain, which corresponded to the significant enrichment of the oxidative phosphorylation pathway. Consistent with this result, PE significantly increased ATP content and protein expression of NDUFB3 (mitochondrial respiratory chain complex I subunit) in macrophages. Meanwhile, transcriptomic data showed that PE treatment downregulated the transcript levels of nlrp3 and upregulated the transcript levels of suppressor of cytokine signaling 3 (socs3), suggesting that PE may alleviate macrophage inflammation by interfering with the activation of NLRP3 inflammasome. Further analysis showed that PE significantly attenuated dietary PA-mediated macrophage inflammation via NLRP3-Caspase-1 in vitro and in vivo. Given that PE abundance is strongly correlated with mitochondrial function, the present study hypothesized that PE-mediated inflammatory modulation may be attributed to the positive effects on mitochondrial function. As expected, PE significantly ameliorated PA-induced mitochondrial dysfunction and reduced intracellular reactive oxygen species production and malondialdehyde content in macrophages, indicating that the improvement of mitochondrial function is an important mechanism involved in the positive effect of PE on PA-induced inflammation. In conclusion, this study elucidates the critical role of mitochondrial function in PE-mediated regulation of inflammation in macrophages, which expands the understanding of the regulatory mechanisms of phospholipid metabolism on dietary fatty acid-induced inflammation. This study may provide new intervention targets and nutritional regulation strategies for improving chronic inflammatory diseases.