240

ALOX5

5-LO|5-LOX|5LPG|LOG5;arachidonate 5-lipoxygenase;ALOX5;arachidonate 5-lipoxygenase

LOX-5|arachidonic 5-lipoxygenase alpha-10 isoform|arachidonic 5-lipoxygenase delta-10-13 isoform|arachidonic 5-lipoxygenase delta-13 isoform|arachidonic 5-lipoxygenase delta-p10 isoform|arachidonic acid 5-lipoxygenase|leukotriene A4 synthase

10q11.2

protein-coding

Count: 5-LO knockout; 25290

Chronically elevated shear stress and inflammation are important in hypertensive lung vessel remodeling. We postulate that 5-lipoxygenase (5-LO) is a molecular determinant of these processes. Immunohistology localized the 5-LO to macrophages of normal and chronically hypoxic rat lungs and also to vascular endothelial cells in chronically hypoxic lungs only. In situ hybridization of normal and chronically hypoxic lungs demonstrated that 5-LO mRNA is expressed in macrophages. Rats hypoxic for 4 wk-developed pulmonary hypertension increased translocation of the lung 5-LO from the cytosol to the membrane fraction and increased levels of lung tissue 5-lipoxygenase-activating protein (FLAP). A FLAP ligand, 3-[l-(4-chlorobenzyl)-3-t-butyl-thio-t-isopropylindol-2-yl]-2,2- dimethylpropanoic acid (MK-886), inhibited the acute angiotensin II and hypoxia-induced pulmonary vasoconstriction in vitro and the development of chronic hypoxic pulmonary hypertension in rats in vivo. Mice bred with the deletion of the 5-LO enzyme (5-LO knockout) developed less right heart hypertrophy than age-matched 5-LO competent mice. Our results support the hypothesis that the 5-LO is involved in lung vascular tone regulation and in the development of chronic pulmonary hypertension in hypoxic rodent models.