Expression and physiological function of CYP4F subfamily in human eosinophils.

We investigated expression of the CYP4F subfamily in human leukocytes by flow cytometry using anti-CYP4F3A antibody and quantitative reverse transcription-polymerase chain reaction (QRT-PCR). More than 90% of CD11b, CD13, CD14, CD33, and eosinophil marker-positive cells expressed CYP4F3A. mRNA for CYP4F3A was found in neutrophils, monocytes, and eosinophils. CYP4F12 mRNA was detected in eosinophils and neutrophils. In eosinophils, transcription of the CYP4F12 gene was started from two sites at 49 and 85 nucleotides upstream from the 3' end of exon I. Recombinant CYP4F12 expressed in yeast cell microsomes catalyzed the omega-hydroxylation of leukotriene B4 (LTB4) and 6-trans-LTB4. In contrast, the CYP4F12 did not show any activity toward eicosanoids such as lipoxin A4 and 12-HETE, which are substrates for CYP4F3A, indicating that the physiological roles of CYP4F3A and CYP4F12 in eosinophils are different.