15-Epi-lipoxin A4 is a lipoxin derivative. Lipoxins (LXs) and aspirin-triggered Lipoxin (ATL) are trihydroxytetraene-containing eicosanoids generated from arachidonic acid that are distinct in structure, formation, and function from the many other proinflammatory lipid-derived mediators. These endogenous eicosanoids have now emerged as founding members of the first class of lipid/chemical mediators involved in the resolution of the inflammatory response. Lipoxin A4 (LXA4), ATL, and their metabolic stable analogs elicit cellular responses and regulate leukocyte trafficking in vivo by activating the specific receptor, ALX. Many of the eicosanoids derived from arachidonic acid (AA2), including prostaglandins (PGs) and leukotrienes (LTs), play important roles as local mediators exerting a wide range of actions relevant in immune hypersensitivity and inflammation. However, recent observations indicate that other agents derived from the lipoxygenase (LO) pathways are formed and play a key role in initiating the resolution of acute inflammation. This phenomenon is an active process that is governed by specific lipid mediators and involves a series of well-orchestrated temporal events. Thus, potent locally released mediators serve as checkpoint controllers of inflammation. In addition to the well-appreciated ability of aspirin to inhibit PGs, aspirin also acetylates cyclooxygenase (COX)-2, triggering the formation of a 15-epimeric form of lipoxins, termed aspirin-triggered LXA4 (ATL). These eicosanoids (i.e., LXA4 and ATL) with a unique trihydroxytetraene structure function as 'stop signals' in inflammation and actively participate in dampening host responses to bring the inflammation to a close, namely, resolution. LXA4 and ATL elicit the multicellular responses via a specific G protein-coupled receptor (GPCR) termed ALX that has been identified in human. (PMID: 16968948, 11478982).
belongs to the class of organic compounds known as lipoxins. These are eicosanoids with a trihydroxyicosatetraenoic acid skeleton (a c20-fatty acid, with the chain bearing three hydroxyl groups and four double bonds). Lipoxins have four double bonds, which are all conjugated. In some cases a hydroxyl group is substituted by a C=O group.
