Maresin

Maresin 1 (MaR1 or 7R,14S-dihydroxy-4Z,8E,10E,12Z,16Z,19Z-docosahexaenoic acid) is a macrophage-derived mediator of inflammation resolution coined from macrophage mediator in resolving inflammation. Maresin 1, and more recently defined maresins, are 12-lipoxygenase-derived metabolites of the omega-3 fatty acid, docosahexaenoic acid (DHA), that possess potent anti-inflammatory, pro-resolving, protective, and pro-healing properties similar to a variety of other members of the specialized proresolving mediators (SPM) class of polyunsaturated fatty acid (PUFA) metabolites. SPM are dihydroxy, trihydroxy, and epoxy-hydroxy metabolites of long chain PUFA made by certain dioxygenase enzymes viz., cyclooxygenases and lipoxygenases. In addition to the maresins, this class of mediators includes: the 15-lipoxygenase (i.e. ALOX15 and/or possibly ALOX15B)-derived Lipoxin A4 and B4 metabolites of the omega 6 fatty acid, arachidonic acid; the cyclooxygenase 2-derived Resolvin E series metabolites of the omega 3 fatty acid, eicosapentaenoic acid; certain 15-lipoxygenase-derived Resolvin D series metabolites of DHA; certain other 15-lipoxygenase-derived protectin D1 and related metabolites of DHA; and the more recently defined and therefore less fully studied 15-lipoxygenase-derived Resolvin Dn-3DPA metabolites of the omega-3 fatty acid n-3 docosapentaenoic acid (n-3 DPA or clupanodonic acid), the cyclooxygenase 2-derived Resolvin T metabolites of this clupanodonic acid, and the 15-lipoxygenase-derived products of the N-acetylated fatty acid amide of the DHA metabolite, docosahexaenoyl ethanolamide (see resolvins). Maresin 1 (MaR1 or 7R,14S-dihydroxy-4Z,8E,10E,12Z,16Z,19Z-docosahexaenoic acid) is a macrophage-derived mediator of inflammation resolution coined from macrophage mediator in resolving inflammation. Maresin 1, and more recently defined maresins, are 12-lipoxygenase-derived metabolites of the omega-3 fatty acid, docosahexaenoic acid (DHA), that possess potent anti-inflammatory, pro-resolving, protective, and pro-healing properties similar to a variety of other members of the specialized proresolving mediators (SPM) class of polyunsaturated fatty acid (PUFA) metabolites. SPM are dihydroxy, trihydroxy, and epoxy-hydroxy metabolites of long chain PUFA made by certain dioxygenase enzymes viz., cyclooxygenases and lipoxygenases. In addition to the maresins, this class of mediators includes: the 15-lipoxygenase (i.e. ALOX15 and/or possibly ALOX15B)-derived Lipoxin A4 and B4 metabolites of the omega 6 fatty acid, arachidonic acid; the cyclooxygenase 2-derived Resolvin E series metabolites of the omega 3 fatty acid, eicosapentaenoic acid; certain 15-lipoxygenase-derived Resolvin D series metabolites of DHA; certain other 15-lipoxygenase-derived protectin D1 and related metabolites of DHA; and the more recently defined and therefore less fully studied 15-lipoxygenase-derived Resolvin Dn-3DPA metabolites of the omega-3 fatty acid n-3 docosapentaenoic acid (n-3 DPA or clupanodonic acid), the cyclooxygenase 2-derived Resolvin T metabolites of this clupanodonic acid, and the 15-lipoxygenase-derived products of the N-acetylated fatty acid amide of the DHA metabolite, docosahexaenoyl ethanolamide (see resolvins). MaR1 was first defined as a product of DHA formed by cultures of human monocyte-derived macrophages. Studies implicate the following pathway in its formation: 12-lipoxygenase converts DHA to its 14-hydroxperoxy intermediate, 14(S)-hydroperoxy-4Z,7Z,10Z,12E,16Z,19Z-DHA (14-HpDHA); 14-HpDHA is converted enzymatically to its 13(S),14(S) epoxy derivative, termed 13(S),14(S)-epoxy-maresin which is then enzymatically hydrolyzed to Mar1. Byproducts of this metabolism include the reduction of 14-HpDHA to its hydroxyl counterpart, 14(S)-hydroxy-4Z,7Z,10Z,12E,16Z,19Z-DHA (14-HDPA); the 5-lipoxygenase-dependent conversion of 14-HpDHA and/or 14-HDHA to 7(S),14(S)-dihydroxy-4Z,8E,10Z,12E,15Z,19Z-DHA; and the non-enzymatic hydrolysis of 14-HpDHA to 7(S/R),14(S)-DHA and 13(S/R)-DHA products. Concurrently, the macrophages also convert DHA to 13(R),14(S)-dihydroxy-4Z,7Z,9E,11E,16Z,19Z-docosapentaenoic acid, i.e. maresin 2 (MaR2). The measurement of 17-HDHA in tissues is used as a marker for the level of activation of the maresin-producing pathway. The maresins have been detected primarily as products made by monocyte-macrophage cells types. MaR1 has been identified in the synovial fluid taken from the joins of patients with rheumatoid arthritis. In a murine model of acute respiratory distress syndrome, MaR1 production was detected; its generation appeared to reflect an interaction between blood platelets and neutrophils wherein 12-lipoxygenase-rich platelets generated 13(S),14(S)-epoxy-maresin which was then passed to neutrophils which hydrolyzed the epoxy maresin to MaR1. Planaria worms metabolize DHA to Mar1 during the healing phase of experimentally induced tissue injury.