Eoxin

eoxin A4

Eoxins are proposed to be a family of proinflammatory eicosanoids (signaling compounds that regulate inflammatory and immune responses). They are produced by human eosinophils (a class of white blood cells), mast cells, the L1236 Reed–Sternberg cell line derived from Hodgkin's lymphoma, and certain other tissues. These cells produce the eoxins by initially metabolizing arachidonic acid, an omega-6 (ω-6) fatty acid, via any enzyme possessing 15-lipoxygenase activity. The product of this initial metabolic step, 15(S)-hydroperoxyeicosatetraenoic acid, is then converted to a series of eoxins by the same enzymes that metabolize the 5-lipoxygenase product of arachidonic acid metabolism, i.e. 5-Hydroperoxy-eicosatetraenoic acid to a series of leukotrienes.[1][2] That is, the eoxins are 14,15-disubstituted analogs of the 5,6-disubstituted leukotrienes.[2][3]

A closely related set of 15-lipoxygenase metabolites are derived from anandamide (i.e. arachidonic acid containing ethanolamine esterified to its carboxy residue). These eoxin-like metabolites, termed eoxamides, are also formed by L1235 Reed-Sternberg cells and proposed to play a role in Hodgkins disease.[4]

Eoxins have been suggested to contribute to inflammation in airway allergies and the development and/or progression of certain types of cancer, particularly Hodgkin's lymphoma (a cancer originating from white blood cells), prostate cancer, and colon carcinoma.[3]

  1. ^ Greene ER, Huang S, Serhan CN, Panigrahy D (November 2011). "Regulation of inflammation in cancer by eicosanoids". Prostaglandins Other Lipid Mediat. 96 (1–4): 27–36. doi:10.1016/j.prostaglandins.2011.08.004. PMC 4051344. PMID 21864702. A well-studied group of autacoid mediators that are the products of arachidonic acid metabolism include: the prostaglandins, leukotrienes, lipoxins and cytochrome P450 (CYP) derived bioactive products. These lipid mediators are collectively referred to as eicosanoids and are generated by distinct enzymatic systems initiated by cyclooxygenase (COX 1 and 2), lipoxygenases (5-LOX, 12-LOX, 15-LOXa, 15-LOXb), and cytochrome P450s, respectively. These pathways are the target of approved drugs for the treatment of inflammation, pain, asthma, allergies, and cardiovascular disorders.
  2. ^ a b Cite error: The named reference Primary eosinophils and mast cells was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference 15-LOX-1 review was invoked but never defined (see the help page).
  4. ^ Forsell PK, Brunnström A, Johannesson M, Claesson HE (2012). "Metabolism of anandamide into eoxamides by 15-lipoxygenase-1 and glutathione transferases". Lipids. 47 (8): 781–91. doi:10.1007/s11745-012-3684-z. PMID 22684912. S2CID 3993616.