Biosynthesis of DPAn-3-derived 13-series resolvins

The polyunsaturated fatty acid (PUFA) ω-3 cis-7,10,13,16,19-docosapentaenoic acid (DPAn-3) is an intermediate in the biosynthesis of docosahexaenoic acid (DHA) from eicosapentaenoic acid (EPA) and is also a precursor for the production of novel bioactive mediators. DPAn-3 can form this precursor when acted upon by cyclooxygenase 2 (COX2). Thus these novel 13-series resolvins (RvT1-4) originate from DPAn-3. In E. coli-infected mice, RvTs accelerated resolution of inflammation and increased survival. RvTs also regulated human and mouse phagocyte responses, stimulating bacterial phagocytosis and regulating inflammasome components. The biosynthetic routes of these RvTs are described here. RvT formation requires neutrophil-endothelial cell interaction and is thought to proceed via a two-step process; COX2 hydroxylates DPAn-3 to 13(R)-DPAn-3 which trafficks to adjacent neutrophils where it is lipoxygenated by 5-lipoxygenase to RvT1-4.