Cytochrome P450 2J2 (CYP2J2) plays a key endogenous role in the epoxidation of arachidonic acid and participates in the oxidation of xenobiotics such as terfenadine. CYP2J2 metabolizes arachidonic acid to epoxyeicosatrienoic acids (EETs), which have been shown to afford protective properties to cardiac tissue after ischemia reperfusion injury. Further benefits of EETs include suppression of reactive oxygen species after hypoxia-reoxygenation to protect against tissue damage. While there is abundant data regarding the activity and induction of CYP2J2, information about the regulation of the CYP2J2 gene is limited. Changes in expression of CYP2J2 will alter EET levels, influencing cardiomyoctye function either positively or negatively. Therefore, various conditions of hypoxia as well as drug treatments were investigated to determine their effect on CYP2J2 mRNA expression and protein activity. Cardiomyocytes were exposed to various conditions followed by mRNA isolation and quantitation by real-time PCR. Additionally, cells were treated with terfenadine, a specific CYP2J2 substrate, to determine the effect of varying conditions on protein activity. Surprisingly, HPRT1, the gene that expresses hypoxanthine phosphoribosyltransferase 1 an enzyme involved in the nucleotide salvage pathway, which is used as a housekeeping gene, has been found to be associated with CYP2J2 expression. Using siRNA to knockdown HPRT1 for 24 hours resulted in a 1.6-3 fold increase of CYP2J2 mRNA expression but did not appreciably increase terfenadine hydroxylation. Treatments including CoCl2, to induce hypoxia, mainly resulted in a decrease in CYP2J2 mRNA expression. However, treatment with hormones, such as estradiol and testosterone showed a 3 fold increase in HPRT1 mRNA expression and an 80 % knockdown of CYP2J2 after 24 hours. These data demonstrate that CYP2J2 expression can be augmented by various conditions of disease, drug treatments and length of treatment.

Investigation of regulation of cytochrome P450 2J2 in adult human primary cardiomyoctyes

249th National Meeting (2015)

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