5(r) hete

5(R)-HETE is a rare lipoxygenase product of arachidonic acid. Nearly all plant and animal 5-LOs produce 5(S)-HETE, but the presence of a 5(R)-LO and the synthesis of 5(R)-HpETE and 5(R)-HETE have been confirmed in oocytes of the bivalve mollusk, S. solidissima. 5(R)-HETE is more potent than the (S)-enantiomer as a chemotactic agent for human neutrophils.

15(R)-HETE, a monohydroxy fatty acid, is synthesized from arachidonic acid via aspirin-acetylated COX-2, leading to the formation of specialized pro-resolving mediators 15(R)-lipoxin A4 and B4 through a transcellular mechanism involving 5-lipoxygenase (5-LO). Additionally, this compound is produced by the cytochrome P450 (CYP) isoform CYP2C9 and can be generated from arachidonic acid by COX-1 in human mast cells, where it accumulates due to its resistance to conversion into 15-KETE by 15-hydroxyprostaglandin dehydrogenase (15-PGDH). As an agonist of PPARβ/δ, 15(R)-HETE induces the expression of a target gene in NIH3T3 cells, demonstrating its biological significance.

Lipid-derived lipoxins are produced at the site of vascular and mucosal inflammation where they down-regulate polymorphonuclear leukocyte recruitment and function. 15(R)-Lipoxin A4 (15(R)-LXA4) is derived from the aspirin-triggered formation of 15(R)-HETE from arachidonic acid. [1] [2] 15(R)-LXA4 inhibits LTB4-induced chemotaxis, adherence, and transmigration of neutrophils with twice the potency of LXA4 demonstrating activity in the nM range.[2] [3] The anti-inflammatory effects of aspirin may be ascribed in part to the ability of 15(R)-LXA4 to regulate leukocyte function.[4] 15(R)-LXA4 is reported to promote resolution of inflammation in LPS-treated stromal cells derived from intermediate-stage diseased supraspinatus tendons as evidenced by increased expression of the STAT-6 pathway target genes, ALOX15 and CD206.[5]

The lipoxins are trihydroxy fatty acids containing a 7,9,11,13-conjugated tetraene. Lipoxin A4 (LXA4) was first described as a metabolite of 15-HpETE and/or 15-HETE when added in vitro to isolated human leukocytes. The material obtained in this manner consists of at least four distinct isomers: 5(S), 6(S); 5(S), 6(R); and the 11-trans and 11-cis isomers of each of these. 6(S)-LXA4 is one of the original four metabolites first identified by Serhan, Nicolaou, and Samuelsson. It was considered to be an artifact by these authors because it lacked the potency of the 5(S),6(R) isomer with respect to contraction of isolated guinea pig lung parenchymal strips. It has not been possible to isolate natural" LXA4 from humans or other mammals in amounts sufficient for determination of absolute stereochemistry. Most authors refer to LXA4 as the 5(S)

5-HETE is a fatty acid metabolite and an oxidative derivative of arachidonic acid produced through lipoxygenase activity, existing as a racemic mixture of the 5(S)-HETE and 5(R)-HETE enantiomers, and it acts as a potent aggregating agent that induces the aggregation of human neutrophils with a IC50 value of approximately 200 nM.