Expression of CYP4F12 in Gastrointestinal and Urogenital Epithelia*

Abstract

Cytochrome P450 4F12 (CYP4F12) was originally cloned from human liver and small intestine. CYP4F12 can oxidize arachidonic acid, two stable prostaglandin H2 analogues, and an antihistamine, ebastine, but the tissue distribution and catalytic properties of CYP4F12 have not been fully investigated. An antipeptide polyclonal antibody was raised against the C-terminal of CYP4F12 (PLNVGLQ), evaluated by Western blot analysis and used for immunohistological analysis of 50 human tissues. Western blot analysis of recombinant CYP4F12, expressed in yeast, and microsomal proteins from adult and foetal liver, kidney, placenta at term, seminal vesicles, the prostate gland and purified prostasomes showed that the polyclonal antibody detected a protein of the expected size, approximately 60 kDa. CYP4F12 mRNA could be detected in seminal vesicles and prostate gland by reverse transcription-PCR. Prominent CYP4F12 immunoreactivity occurred, inter alia, in the epithelial cells of the gastrointestinal tract (stomach, small intestine, and colon), collecting tubules, transitional epithelium, ovarian follicles, the endothelium of microvessels of placental villi (first trimester), and epidermis. We screened recombinant CYP4F12 for catalytic activity. Arachidonic acid (20:4n-6) was hydroxylated at C18 and laurate at C11, but significant amounts of metabolites of 18:2n-6, 20:3n-9, 20:5n-3, 22:5n-6, and some prostaglandins could not be detected. We conclude that CYP4F12 is widely distributed in gastrointestinal and urogenital epithelia and exhibits a narrow substrate specificity.

Distinction between Human Cytochrome P450 (CYP) Isoforms and Identification of New Phosphorylation Sites by Mass Spectrometry

“…Notably, hepatic expression of CYP2C18 protein is extremely low 45 and CYP4F12 is reported to be mainly expressed in the gastrointestinal and urogenital epithelia. 46 Additionally, relative semiquantification between the samples from different donors is possible, although this was not the aim of this study; thereby it can be determined that, for example, a higher amount of CYP2A6 is expressed in donor 3 and 4 (19 and 25 peptides assigned to the protein) in comparison to donor 1 or 2 (6 and 14 peptides assigned to the protein) (Table 2). However, CYP4F3 is an example that points out the limitation of this semiquantitative approach.…”

Age-related changes in the mRNA levels of CYP1A1, CYP2B1/2 and CYP3A1 isoforms in rat small intestine

“…The CYP1A1 isoform shows the highest level of expression in rat small intestine (Zhang et al 1999). The other CYP450 isoforms were found in the epithelium of rat small intestine include CYP1A2 (Hakkak and Ronis 1993), CYP2B, CYP2C, CYP2E1, CYP3A, (Perloff et al 2004;Takemoto et al 2003), CYP4A1 (Catterall et al 2003), CYP4F12 (Stark et al 2004), CYP2J4 and CYP2J3 (Zhang et al 1998). The extended exposure to the ritonavir and dexamethasone increased the expression of CYP3A isoforms in rat enteric mucosal cells (Perloff et al 2004).…”

Characterization of Orphan Human Cytochromes P450

“…P450 4A22, 4F11, 4F22, 4V2, 4X1, and 4Z1 . Although not acknowledged as an orphan enzyme, CYP4F12 (originally cloned from liver and intestine) may also be included in the group (Bylund et al, 2001;Kikuta et al, 2002;Stark et al, 2004), as no endogenous substrate with a high conversion rate has been found.…”