title: Cytochrome P4502S1: a novel monocyte/macrophage fatty acid epoxygenase in human atherosclerotic plaques.
abstract: Cytochrome P450 (CYP) epoxygenases metabolize endogenous polyunsaturated fatty acids to their corresponding epoxides, generating bioactive lipid mediators. The latter play an important role in vascular homeostasis, angiogenesis, and inflammation. As little is known about the functional importance of extra-vascular sources of lipid epoxides, we focused on determining whether lipid epoxide-generating CYP isoforms are expressed in human monocytes/macrophages. Epoxides were generated by freshly isolated human monocytes and production increased markedly during differentiation to macrophages. Mass spectrometric analysis identified CYP2S1 as a novel macrophage CYP and CYP2S1-containing microsomes generated epoxides of arachidonic, linoleic and eicosapentaenoic acid. Macrophage CYP2S1 expression was increased by LPS and IFN-γ (classically activated), and oxidized LDL but not IL-4 and IL-13 (alternatively activated), and was colocalised with CD68 in inflamed human tonsils but not in breast cancer metastases. Prostaglandin (PG) E(2) is an immune modulator factor that promotes phagocytosis and CYP2S1 can metabolize its immediate precursors PGG(2) and PGH(2) to 12(S)-hydroxyheptadeca-5Z,8E,10E-trienoic acid (12-HHT). We found that CYP inhibition and siRNA-mediated downregulation of CYP2S1 increased macrophage phagocytosis and that the latter effect correlated with decreased 12-HHT formation. Although no Cyp2s1 protein was detected in aortae from wild-type mice it was expressed in aortae and macrophage foam cells from ApoE(-/-) mice. Consistent with these observations CYP2S1 was colocalised with the monocyte marker CD68 in human atherosclerotic lesions. Thus, CYP2S1 generates 12-HHT and is a novel regulator of macrophage function that is expressed in classical inflammatory macrophages, and can be found in murine and human atherosclerotic plaques.
authors.affiliation: Institute for Vascular Signalling, Centre for Molecular Medicine, Johann Wolfgang Goethe University and DZHK (German Centre for Cardiovascular Research) partner site Rhine-Main, Theodor Stern Kai 7, 60596 Frankfurt am Main, Germany.
authors.forename: Timo
authors.initials: T
authors.lastname: Frömel
authors.forename: Karin
authors.initials: K
authors.lastname: Kohlstedt
authors.forename: Rüdiger
authors.initials: R
authors.lastname: Popp
authors.forename: Xiaoke
authors.initials: X
authors.lastname: Yin
authors.forename: Khader
authors.initials: K
authors.lastname: Awwad
authors.forename: Eduardo
authors.initials: E
authors.lastname: Barbosa-Sicard
authors.forename: Anita C
authors.initials: AC
authors.lastname: Thomas
authors.forename: Ralf
authors.initials: R
authors.lastname: Lieberz
authors.forename: Manuel
authors.initials: M
authors.lastname: Mayr
authors.forename: Ingrid
authors.initials: I
authors.lastname: Fleming
mesh_terms: D015126:8,11,14-Eicosatrienoic Acid / Q000031:analogs & derivatives / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D015703:Antigens, CD / Q000032:analysis; D015214:Antigens, Differentiation, Myelomonocytic / Q000032:analysis; D001057:Apolipoproteins E / Q000502:physiology; D002478:Cells, Cultured; D003577:Cytochrome P-450 Enzyme System / Q000032:analysis / Q000737:chemistry / Q000502:physiology*; D005231:Fatty Acids, Unsaturated / Q000378:metabolism*; D006801:Humans; D008264:Macrophages / Q000201:enzymology* / Q000502:physiology; D051379:Mice; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D009000:Monocytes / Q000201:enzymology*; D010587:Phagocytosis; D058226:Plaque, Atherosclerotic / Q000201:enzymology*; D000097382:CD68 Molecule
chemical_list: D015126:8,11,14-Eicosatrienoic Acid; D015703:Antigens, CD; D015214:Antigens, Differentiation, Myelomonocytic; D001057:Apolipoproteins E; D003577:Cytochrome P-450 Enzyme System; D005231:Fatty Acids, Unsaturated; C067980:CD68 antigen, human; D000097382:CD68 Molecule; C008033:12-hydroxy-5,8,10-heptadecatrienoic acid; C040776:5,6-epoxy-8,11,14-eicosatrienoic acid; C422564:CYP2S1 protein, human; C582632:Cyp2s1 protein, mouse