Generation and Characterization of aCyp2f2-Null Mouse and Studies on the Role of CYP2F2 in Naphthalene-Induced Toxicity in the Lung and Nasal Olfactory Mucosa

Abstract

The CYP2F enzymes, abundantly expressed in the respiratory tract, are active toward many xenobiotic compounds, including naphthalene (NA). However, the precise roles of these enzymes in tissue-selective chemical toxicity have been difficult to resolve. A Cyp2f2-null mouse was generated in this study by disrupting the Cyp2f2 fourth exon. Homozygous Cyp2f2-null mice, which had no CYP2F2 expression and showed no changes in the expression of other P450 genes examined, were viable and fertile and had no in utero lethality or developmental deficits. The loss of CYP2F2 expression led to substantial decreases in the in vitro catalytic efficiency of microsomal NA epoxygenases in lung (up to ϳ160-fold), liver (ϳ3-fold), and nasal olfactory mucosa (OM; up to ϳ16-fold), and significant decreases in rates of systemic NA (300 mg/kg i.p.) clearance. The Cyp2f2-null mice were largely resistant to NA-induced cytotoxicity, when examined at 24 h after NA dosing (at 300 mg/kg i.p.), and to NA-induced depletion of total nonprotein sulfhydryl (NPSH), examined at 2 h after dosing, in the lungs. In contrast, the loss of CYP2F2 expression did not alleviate NAinduced NPSH depletion or tissue toxicity in the OM. Mouse CYP2F2 clearly plays an essential role in the bioactivation and toxicity of NA in the lung but not in the OM. The Cyp2f2-null mouse should be valuable for studies on the role of CYP2F2 in the metabolism and toxicity of numerous other xenobiotic compounds and for future production of a CYP2F1-humanized mouse.

Respective Roles of CYP2A5 and CYP2F2 in the Bioactivation of 3-Methylindole in Mouse Olfactory Mucosa and Lung: Studies Using Cyp2a5-Null and Cyp2f2-Null Mouse Models

“…The Cyp2a5-null and Cyp2f2-null mice have been found to be valuable for demonstrating the roles of CYP2A5 or CYP2F2 in mediating the tissue-specific toxicities in the respiratory tract induced by acetaminophen , 2,6-dichlorobenzonitrile , and naphthalene (Li et al, 2011). Here, we show that whereas CYP2F2 plays a critical role in the 3MI metabolism in the lung, both CYP2A5 and CYP2F2 play important roles in 3MI metabolism in the OM.…”

“…Both CYP2A5 and CYP2F2 can metabolize numerous toxicants (see Su and Ding, 2004;Zhang and Ding, 2008). CYP2A5 is abundantly expressed in OM, and at much lower levels in other tissues, including the lung (see Su and Ding, 2004), whereas CYP2F2 is expressed in the liver, lung, and OM at comparable levels (Baldwin et al, 2004;Li et al, 2011).…”

“…In the present study, we have determined whether CYP2A5 and CYP2F2 play critical roles in the bioactivation of 3MI in mouse lung and OM in vitro, by comparing the metabolite profiles and enzyme kinetics of 3MI metabolism among wild-type (WT), Cyp2a5-null , and Cyp2f2-null mice (Li et al, 2011). The Cyp2a5-null and Cyp2f2-null mice have been found to be valuable for demonstrating the roles of CYP2A5 or CYP2F2 in mediating the tissue-specific toxicities in the respiratory tract induced by acetaminophen , 2,6-dichlorobenzonitrile , and naphthalene (Li et al, 2011).…”

Generation and Characterization of aCYP2A13/2B6/2F1-Transgenic Mouse Model

“…Recombinant CYP2B6 in a Sf9 cell microsomal preparation (BD Gentest) was used as a standard for immunoblot quantification. A rabbit anti-peptide antibody to CYP2F1/2, which was used previously for characterization of Cyp2f2-null mice (Li et al, 2011), was used for detection of CYP2F1 protein in microsomes from TG(ϩ/Ϫ)/Cyp2f2(Ϫ/Ϫ) mice. The sequence of the antigenic peptide [NH 2 -(C)TPQEFNPEHFLD-COOH, corresponding to amino acids 404 -415 of CYP2F1; the first cysteine was added for conjugation] is shared by CYP2F1 and CYP2F2.…”

“…TG mice were also crossbred with Cyp2f2-null mice (Li et al, 2011); the resultant TG(ϩ/Ϫ)/Cyp2f2(Ϫ/Ϫ) mice were used for detection of CYP2F1 protein without interference from mouse CYP2F2. All studies with mice were approved by the Wadsworth Center Institutional Animal Care and Use Committee.…”