Eoxin

From Biology-Online Dictionary | Biology-Online Dictionary

Definition

noun, plural: eoxins

Any of the proinflammatory eicosanoids produced by eosinophils, mast cells, and other cells of tissues by oxidizing arachidonic acid through an enzyme with 15-lipoxygenase activity


Supplement

Eicosanoid is the generic term to refer to the compounds derived from arachidonic acid or other polyunsaturated fatty acids of 20-carbon length. Some of the prominent eicosanoids include (1) eoxins, (2) leukotrienes, (3) lipoxins, (4) prostacyclin, (5) prostaglandins, (6) resolvins, and (7) thromboxanes.

Eoxins is a subfamily of eicosanoids that regulate inflammatory and immune responses. Some of the cells that produce eoxins are eosinophils, mast cells, nasal polyps from individuals with allergies, airway epithelial cells, and the L1236 Reed-Sternberg cell line derived from Hodgkin's Lymphoma. In fact, the name eoxin is derived from human eosinophils where they were first observed and are produced in abundance. These cells synthesize eoxins by first oxidizing arachidonic acid through any enzyme with 15-lipoxygenase activity to produce a metabolite [i.e. 15(S)-HpETE] that will be converted serially and enzymatically to eoxins. The four chemically distinct eosins are eoxin A4 (EXA4), eoxin C4 (EXC4), eoxin D4 (EXD4), and eoxin E4 (EXE4). The biochemical pathway is as follows:

Arachidonic acid + O2 → 15(S)-HpETE → EXA4 → EXC4 → EXD4 → EXE4

Eoxins are thought to promote inflammation in airway allergies and the development of certain cancers (e.g. Hodgkin's lymphoma, prostate cancer, and colon carcinoma).


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