Recombinant Cytochrome P450 1B1 Research Articles

11-Hydroxyeicosatetraenoics induces cellular hypertrophy in an enantioselective manner.

R/S enantiomers of 11-hydroxyeicosatertraenoic acid (11-HETE) are formed from arachidonic acid by enzymatic and non-enzymatic pathways. 11-HETE is predominately formed by the cytochrome P450 1B1 (CYP1B1). The role of CYP1B1 in the development of cardiovascular diseases is well established. This study aimed to assess the cellular hypertrophic effect of 11-HETE enantiomers in human RL-14 cardiomyocyte cell line and to examine their association with CYP1B1 levels. Human fetal ventricular cardiomyocyte, RL-14 cells, were treated with 20µM (R) or (S) 11-HETE for 24h. Thereafter, cellular hypertrophic markers and cell size were then determined using real-time polymerase chain reaction (RT-PCR) and phase-contrast imaging, respectively. The mRNA and protein levels of selected CYPs were determined using RT-PCR and Western blot, respectively. In addition, we examined the effect of (R) and (S) 11-HETE on CYP1B1 catalytic activity using human recombinant CYP1B1 and human liver microsomes. Both (R) and (S) 11-HETE induced cellular hypertrophic markers and cell surface area in RL-14 cells. Both enantiomers significantly upregulated CYP1B1, CYP1A1, CYP4F2, and CYP4A11 at the mRNA and protein levels, however, the effect of the S-enantiomer was more pronounced. Furthermore, 11(S)-HETE increased the mRNA and protein levels of CYP2J and CYP4F2, whereas 11(R)-HETE increased only CYP4F2. Only 11(S)-HETE significantly increased the catalytic activity of CYP1B1 in recombinant human CYP1B1, suggesting allosteric activation in an enantioselective manner. Our study provides the first evidence that 11-HETE can induce cellular hypertrophy in RL-14 cells via the increase in CYP1B1 mRNA, protein, and activity levels.

17-(R/S)-hydroxyeicosatetraenoic acid (HETE) induces cardiac hypertrophy through the CYP1B1 in enantioselective manners

Cardiac cellular hypertrophy is the increase in the size of individual cardiac cells. Cytochrome P450 1B1 (CYP1B1) is an extrahepatic inducible enzyme that is associated with toxicity, including cardiotoxicity. We previously reported that 19-hydroxyeicosatetraenoic acid (19-HETE) inhibited CYP1B1 and prevented cardiac hypertrophy in enantioselective manner. Therefore, our aim is to investigate the effect of 17-HETE enantiomers on cardiac hypertrophy and CYP1B1. Human adult cardiomyocyte (AC16) cells were treated with 17-HETE enantiomers (20 µM); cellular hypertrophy was evaluated by cell surface area and cardiac hypertrophy markers. In addition, CYP1B1 gene, protein and activity were assessed. Human recombinant CYP1B1 and heart microsomes of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-treated rats were incubated with 17-HETE enantiomers (10–80 nM). Our results demonstrated that 17-HETE induced cellular hypertrophy, which is manifested by increase in cell surface area and cardiac hypertrophy markers. 17-HETE enantiomers allosterically activated CYP1B1 and selectively upregulated CYP1B1 gene and protein expression in AC16 cells at uM range. In addition, CYP1B1 was allosterically activated by 17-HETE enantiomers at nM range in recombinant CYP1B1 and heart microsomes. In conclusion, 17-HETE acts as an autocrine mediator, leading to the cardiac hypertrophy through induction of CYP1B1 activity in the heart.

Unraveling the Structure-Dependent Inhibitory Effects of Ginsenoside Series Compounds on Human Cytochrome P450 1B1.

Cytochrome P450 1B1(CYP1B1) is an extrahepatic P450 isoenzyme that can participate in processes of undermining the effectiveness and safety of anti-cancer therapy. Ginsenosides are the main active ingredients in ginseng, which possesses rich pharmacological activities, including anti-cancer activity and organ protection. However, the effect of ginsenosides on the activity of CYP1B1 remains unclear. The present study aimed to investigate the inhibitory effect of ginsenosides on CYP1B1 and reveal the structure-inhibitory activity relationship. Firstly, recombinant CYP1B1 and EROD reactions were used to evaluate the inhibitory effect of ginsenosides. Secondly, molecular docking was used to simulate the interactions between ginsenosides and CYP1B1. Finally, the structure-inhibitory activity relationship was analyzed. The ginsenosides, Rb2, Rd, and Rg3, significantly inhibited CYP1B1; the ginsenoside Rd showed the strongest inhibition effect, with a Ki value of 47.37 μM in non-competitive mode. Notably, ginsenoside Rd formed hydrogen bonds with two key amino acid residues of CYP1B1, and one bond was between the glycosyl in position 20 and ALA330, which also made ginsenoside Rd close to the heme iron of CYP1B1. In contrast, ginsenosides, Rb2 and Rg3, which showed weaker inhibition, interacted with only one CYP1B1 residue by the hydrogen bond, which was far away from the heme iron. Finally, the structure-inhibitory activity relationship analysis demonstrated that the number of glycosyls in position 20 and the type of sapogenins in the ginsenoside structure are the key factors determining inhibitory activity. Meanwhile, ALA330 was a vital amino acid in the potent inhibition of CYP1B1 by ginsenosides. A structure-dependent inhibitory effect on CYP1B1 was revealed for ginsenosides, among which ginsenoside Rd showed the strongest inhibition due to its mono-glycosyl in position 20 of the ginsenoside parent structure. These findings would provide evidence for the synthesis of novel CYP1B1 inhibitors to augment the anti-cancer therapeutic effect.

Ameliorative Role of Fluconazole Against Abdominal Aortic Constriction-Induced Cardiac Hypertrophy in Rats.

Cytochrome P450 1B1 (CYP1B1) is known to be involved in the pathogenesis of several cardiovascular diseases, including cardiac hypertrophy and heart failure, through the formation of cardiotoxic metabolites named as mid-chain hydroxyeicosatetraenoic acids (HETEs). Recently, we have demonstrated that fluconazole decreases the level of mid-chain HETEs in human liver microsomes, inhibits human recombinant CYP1B1 activity, and protects against angiotensin II-induced cellular hypertrophy in H9c2 cells. Therefore, the overall purpose of this study was to elucidate the potential cardioprotective effect of fluconazole against cardiac hypertrophy induced by abdominal aortic constriction (AAC) in rats. Male Sprague-Dawley rats were randomly assigned into 4 groups such as sham control rats, fluconazole-treated (20 mg/kg daily for 4 weeks, intraperitoneal) sham rats, AAC rats, and fluconazole-treated (20 mg/kg) AAC rats. Baseline and 5 weeks post-AAC echocardiography were performed. Gene and protein expressions were measured using real-time PCR and Western blot analysis, respectively. The level of mid-chain HETEs was determined using liquid chromatography-mass spectrometry. Echocardiography results showed that fluconazole significantly prevented AAC-induced left ventricular hypertrophy because it ameliorated the AAC-mediated increase in left ventricular mass and wall measurements. In addition, fluconazole significantly prevented the AAC-mediated increase of hypertrophic markers. The antihypertrophic effect of fluconazole was associated with a significant inhibition of CYP1B1, CYP2C23, and 12-LOX and a reduction in the formation rate of mid-chain HETEs. This study demonstrates that fluconazole protects against left ventricular hypertrophy, and it highlights the potential repurposing of fluconazole as a mid-chain HETEs forming enzymes' inhibitor for the protection against cardiac hypertrophy.

Fluconazole Protects against Abdominal Aortic Constriction‐Induced Cardiac Hypertrophy

Purpose: Cytochrome P450 1B1 (CYP1B1) is known to be involved in the pathogenesis of several cardiovascular diseases such as cardiac hypertrophy and heart failure, through the formation of cardiotoxic metabolites named as midchain hydroxyeicosatetraenoic acids (HETEs). Recently, we have demonstrated that fluconazole, an antifungal agent, decreases the level of mid-chain HETEs in human liver microsomes, inhibits human recombinant CYP1B1 activity and protects against angiotensin II-induced cellular hypertrophy in H9c2 cells. Therefore, the overall objectives of the present study were to elucidate the potential cardioprotective effect of fluconazole against cardiac hypertrophy induced by abdominal aortic constriction (AAC) and unravel the mechanism(s) involved. Methods: Male Sprague-Dawley rats were randomly assigned into four groups; sham control rats, fluconazole-treated (20 mg/kg daily for 4 weeks, intraperitoneal) sham rats, AAC rats and fluconazole-treated (20 mg/kg) AAC rats. Baseline and 5 weeks post-AAC echocardiography were performed. Gene and protein expression were measured using real-time PCR and Western blot analysis, respectively. The level of mid-chain HETEs was determined using liquid chromatography–mass spectrometry (LC/MS). Results: Echocardiography results showed that fluconazole significantly reversed the AAC-induced left ventricular hypertrophy, as it was able to ameliorate the AAC-mediated increase in left ventricular mass and several wall measurements. In addition, fluconazole significantly prevented the AAC-mediated increase of hypertrophic markers, β-myosin heavy chain (MHC)/α-MHC and atrial natriuretic peptide (ANP). The antihypertrophic effect of fluconazole was associated with a significant inhibition of CYP1B1 at the gene and protein levels as well as a reduction in the formation rate of midchain HETEs. Conclusion: The current study demonstrates a strong evidence that fluconazole protects against left ventricular hypertrophy. The findings of the present work highlight the potential repurposing of fluconazole as a CYP1B1 inhibitor for the protection against cardiac hypertrophy and a possible treatment for heart failure.

Identification of 19-(S/R)Hydroxyeicosatetraenoic Acid as the First Endogenous Noncompetitive Inhibitor of Cytochrome P450 1B1 with Enantioselective Activity.

The overexpression of cytochrome P450 1B1 (CYP1B1) is a common characteristic of several diseases and conditions, such as inflammation, cancer, and cardiac hypertrophy. CYP1B1 is believed to contribute to pathogenesis of these diseases by mediating the formation of toxic compounds, either from exogenous or endogenous origin. We recently reported that an arachidonic acid metabolite, 19(S/R-)hydroxyeicosatetraenoic (HETE) acid, protects from cardiac hypertrophy by inhibiting the formation of toxic compounds, midchain HETEs, known to be formed by CYP1B1. This raised the question whether 19(S/R)-HETE can directly inhibit CYP1B1. In the current study, we report that 19(S/R)-HETE enantioselectively inhibits human recombinant CYP1B1 activity measured by 7-ethoxyresorufin O-deethylation assay. 19(S)-HETE is more potent than the R enantiomer (K i = 37.3 and 89.1 nM, respectively). Noncompetitive inhibition was identified as the mechanism of CYP1B1 inhibition, which underlines the potentially important physiologic role of 19(S/R)-HETE as an endogenous CYP1B1 inhibitor; to our knowledge, 19(S/R)-HETE is the first inhibitor of its kind to be reported.