title: Cytochrome P-450 4F18 is the leukotriene B4 omega-1/omega-2 hydroxylase in mouse polymorphonuclear leukocytes: identification as the functional orthologue of human polymorphonuclear leukocyte CYP4F3A in the down-regulation of responses to LTB4.
abstract: Leukotriene B(4) (LTB(4)) is a potent chemoattractant for polymorphonuclear leukocytes (PMN) and other cells. Human PMN inactivate LTB(4) by omega-oxidation catalyzed by cytochrome P-450 (CYP) 4F3A. The contribution of the enzymatic inactivation of LTB(4) by CYP4Fs to down-regulating functional responses of cells to LTB(4) is unknown. To elucidate the role of CYP4F-mediated inactivation of LTB(4) in terminating the responses of PMN to LTB(4) and to identify a target for future genetic studies in mice, we have identified the enzyme that catalyzes the omega-1 and omega-2 oxidation of LTB(4) in mouse myeloid cells as CYP4F18. As determined by mass spectrometry, this enzyme catalyzes the conversion of LTB(4) to 19-OH LTB(4) and to a lesser extent 18-OH LTB(4). Inhibition of CYP4F18 resulted in a marked increase in calcium flux and a 220% increase in the chemotactic response of mouse PMN to LTB(4). CYP4F18 expression was induced in bone marrow-derived dendritic cells by bacterial lipopolysaccharide, a ligand for TLR4, and by poly(I.C), a ligand for TLR3. However, when bone marrow-derived myeloid dendritic cells trafficked to popliteal lymph nodes from paw pads, the expression of CYP4F18 was down-regulated. The results identify CYP4F18 as a critical protein in the regulation of LTB(4) metabolism and functional responses in mouse PMN and identify it as the functional orthologue of human PMN CYP4F3A.
authors.affiliation: Renal Unit and Department of Medicine, Massachusetts General Hospital (East), Navy Yard Bldg. 149, 13th Street, Charlestown, MA 02129, USA.
authors.forename: Peter
authors.initials: P
authors.lastname: Christmas
authors.forename: Karine
authors.initials: K
authors.lastname: Tolentino
authors.forename: Valeria
authors.initials: V
authors.lastname: Primo
authors.forename: Karin Zemski
authors.initials: KZ
authors.lastname: Berry
authors.forename: Robert C
authors.initials: RC
authors.lastname: Murphy
authors.forename: Mei
authors.initials: M
authors.lastname: Chen
authors.forename: David M
authors.initials: DM
authors.lastname: Lee
authors.forename: Roy J
authors.initials: RJ
authors.lastname: Soberman
mesh_terms: D000818:Animals; D001853:Bone Marrow / Q000378:metabolism; D002118:Calcium / Q000737:chemistry; D002384:Catalysis; D002454:Cell Differentiation; D002633:Chemotaxis; D002851:Chromatography, High Pressure Liquid; D003577:Cytochrome P-450 Enzyme System / Q000737:chemistry* / Q000378:metabolism; D000072470:Cytochrome P450 Family 4; D017931:DNA Primers / Q000737:chemistry; D018076:DNA, Complementary / Q000378:metabolism; D015536:Down-Regulation; D005091:Exons; D005260:Female; D005434:Flow Cytometry; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D007975:Leukotriene B4 / Q000737:chemistry*; D008024:Ligands; D008099:Liver / Q000378:metabolism; D008264:Macrophages / Q000378:metabolism; D017737:Macrophages, Peritoneal / Q000378:metabolism; D008297:Male; D013058:Mass Spectrometry; D051379:Mice; D008807:Mice, Inbred BALB C; D008856:Microscopy, Fluorescence; D006899:Mixed Function Oxygenases / Q000737:chemistry*; D008957:Models, Genetic; D009504:Neutrophils / Q000378:metabolism*; D010100:Oxygen / Q000737:chemistry; D020033:Protein Isoforms; D012313:RNA / Q000737:chemistry; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors; D014018:Tissue Distribution
chemical_list: D017931:DNA Primers; D018076:DNA, Complementary; D008024:Ligands; D020033:Protein Isoforms; D007975:Leukotriene B4; D012313:RNA; D003577:Cytochrome P-450 Enzyme System; D006899:Mixed Function Oxygenases; D000072470:Cytochrome P450 Family 4; C465349:CYP4F3 protein, human; C040780:leukotriene B4 20-hydroxylase; D010100:Oxygen; D002118:Calcium