Dilinoleoylphosphatidylcholine induces the expression of the anti-inflammatory heme oxygenase-1 in RAW264.7 macrophages

1,2-Dilinoleoyl-sn-glycero-3-phosphocholine (DLPC), the main and active component of soybean lecithin, has been reported to exert anti-inflammatory effects, but the underlying mechanisms remain to be established. It was found that DLPC could induce the expression of the anti-inflammatory heme oxygenase-1 (HO-1) through the activation of nuclear erythroid 2-related factor 2 (Nrf2) in RAW264.7 macrophages. Pretreatment with DLPC suppressed the expression of inducible nitric oxide (NO) synthase (iNOS), one of proinflammatory enzymes, and reduced NO production in lipopolysaccharide (LPS)stimulated macrophages. Similarly, DLPC also diminished the production of tumor necrosis factor-alpha (TNF-alpha), one of proinflammatory cytokines. Interestingly, the inhibitory effects of DLPC on LPS-induced iNOS expression and TNF-alpha production were reversed by tin protoporphyrin, a HO-1 inhibitor. Thus, HO-1 expression via Nrf2 activation may be one of the possible mechanisms explaining the anti-inflammatory effects of DLPC.