title: Differentiating keratinocytes express a novel cytochrome P450 enzyme, CYP2B19, having arachidonate monooxygenase activity.
abstract: The novel cytochrome P450, CYP2B19, is a specific cellular marker of late differentiation in skin keratinocytes. CYP2B19 was discovered in fetal mouse skin where its onset of expression coincides spatially (upper cell layer) and temporally (day 15.5) with the appearance of loricrin-expressing keratinocytes during the stratification stage of fetal epidermis. CYP2B19 is also present postnatally in the differentiated keratinocytes of the epidermis, sebaceous glands, and hair follicles. CYP2B19 mRNA is tightly coupled to the differentiated (granular cell) keratinocyte phenotype in vivo and in vitro. In primary mouse epidermal keratinocytes, it is specifically up-regulated and correlated temporally with calcium-induced differentiation and expression of the late differentiation genes loricrin and profilaggrin. Recombinant CYP2B19 metabolizes arachidonic acid and generates 14,15- and 11, 12-epoxyeicosatrienoic (EET) acids, and 11-, 12-, and 15-hydroxyeicosatetraenoic (HETE) acids (20, 35, 18, 7, and 7% of total metabolites, respectively). Arachidonic acid metabolism was stereoselective for 11S,12R- and 14S,15R-EET, and 11S-, 12R-, and 15R-HETE. The CYP2B19 metabolites 11,12- and 14,15-EET are endogenous constituents of murine epidermis and are present in similar proportions to that generated by the enzyme in vitro, suggesting that CYP2B19 might be the primary enzymatic source of these EETs in murine epidermis.
authors.affiliation: Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232-0146, USA. diane.keeney@vanderbilt.edu
authors.forename: D S
authors.initials: DS
authors.lastname: Keeney
authors.forename: C
authors.initials: C
authors.lastname: Skinner
authors.forename: J B
authors.initials: JB
authors.lastname: Travers
authors.forename: J H
authors.initials: JH
authors.lastname: Capdevila
authors.forename: L B
authors.initials: LB
authors.lastname: Nanney
authors.forename: L E
authors.initials: LE
authors.lastname: King
authors.forename: M R
authors.initials: MR
authors.lastname: Waterman
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001095:Arachidonic Acids / Q000378:metabolism; D001189:Aryl Hydrocarbon Hydroxylases; D001483:Base Sequence; D015415:Biomarkers; D002454:Cell Differentiation; D002478:Cells, Cultured; D000072467:Cytochrome P450 Family 2; D000078404:Epidermal Cells; D004817:Epidermis / Q000201:enzymology; D005333:Fetus; D015971:Gene Expression Regulation, Enzymologic; D006197:Hair / Q000166:cytology / Q000201:enzymology; D015603:Keratinocytes / Q000166:cytology / Q000201:enzymology*; D007633:Keratins / Q000235:genetics; D008565:Membrane Proteins / Q000235:genetics; D051379:Mice; D006899:Mixed Function Oxygenases; D008969:Molecular Sequence Data; D010105:Oxygenases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D012627:Sebaceous Glands / Q000166:cytology / Q000201:enzymology; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D012867:Skin / Q000166:cytology / Q000201:enzymology; D013379:Substrate Specificity; D014158:Transcription, Genetic
chemical_list: D001095:Arachidonic Acids; D015415:Biomarkers; D008565:Membrane Proteins; D012333:RNA, Messenger; C064554:loricrin; D007633:Keratins; D006899:Mixed Function Oxygenases; D010105:Oxygenases; D001189:Aryl Hydrocarbon Hydroxylases; C033914:Cyp2b19 protein, mouse; D000072467:Cytochrome P450 Family 2