The regulation of inflammation by oxidized phospholipids

During inflammation or under conditions of oxidative stress, the polyunsaturated fatty acid side chains of phospholipids in cellular membranes or lipoproteins can be oxidatively modified. This process generates a complex mixture of structurally diverse oxidized phospholipid (OxPL) species, each of which may exert distinct biological effects. The presence of OxPLs has been documented in acute and chronic microbial infections, metabolic disorders, and degenerative diseases. It is now well recognized that OxPLs actively influence biological processes and contribute to the induction and resolution of inflammation. While many pro- and anti-inflammatory effects have been documented for bulk OxPL preparations, we are only beginning to understand the exact molecular mechanisms and signaling events that mediate the individual proinflammatory or anti-inflammatory bioactivities of discrete isolated OxPL species. Here, we review the current knowledge on the regulation of inflammation by OxPLs and summarize recent studies that establish cyclopentenone-containing OxPLs as a category of potent anti-inflammatory lipid mediators.