15-Lipoxygenase type 1 (15-LO), a lipid-peroxidating enzyme implicated in physiological membrane remodeling and the pathogenesis of atherosclerosis, inflammation, and carcinogenesis, is highly regulated and expressed in a tissue- and cell-type-specific fashion.
Also, overexpression of the 15-LOX Type 1 in transgenic rabbits leads to a reduced inflammatory phenotype and protection from periodontal disease, as well as atherosclerosis.
12/15-LOXs are capable of oxidizing lipoproteins (low-density lipoprotein (LDL), high-density lipoprotein (HDL)) to atherogenic forms, and functional inactivation of this enzyme in murine atherosclerosis models slows down lesion formation.
Examination of knockout and transgenic animals revealed important roles for 12/15-LOX in inflammatory diseases, including atherosclerosis, cancer, osteoporosis, angiotension II-dependent hypertension and diabetes.
Thus, the paradoxical increase in LDL oxidation by endothelial cells is attributable to higher oxidant activity of 12/15-lipoxygenase in BALB/c mice and endothelial cells appear unlikely to be a source of the resistance to atherosclerosis.
Reticulocyte-type 15-lipoxygenase-1 (ALOX15) has anti-inflammatory and inflammatory effects and is implicated in the development of asthma, arthritis and atherosclerosis.
Results from these indicate that 12/15-lipoxygenase expression protects mice against atherosclerosis via its role in the local biosynthesis of lipid mediators, including lipoxin A(4), resolvin D1, and protectin D1.
These data suggest that ALOX15 may play a less prominent role during later stages of atherosclerosis involving atherothrombotic mechanisms than eventually during early plaque development.
Hyperlipidemia not only affected the biosynthesis of lipoxin A4, a key pro-resolving mediator, but also disrupted the protective pro-resolving function of 12/15-LOX products, and the enzyme pathway no longer protected against atherosclerosis in vivo.
Genetic or pharmacological inhibition of 12/15-LOX dramatically attenuated the deposition of oxidized LDL in the subendothelial space and the development of atherosclerosis.