CYP4 Enzymes As Potential Drug Targets: Focus on Enzyme Multiplicity, Inducers and Inhibitors, and Therapeutic Modulation of 20- Hydroxyeicosatetraenoic Acid (20-HETE) Synthase and Fatty Acid &amp;#969;- Hydroxylase Activities

Edson, Katheryne Z.; Rettie, Allan E.

doi:10.2174/15680266113139990110

Cited by 87 publications

(69 citation statements)

References 92 publications

(102 reference statements)

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“…However, unlike other members of CYP4, the sub-family CYP4B1 not only has the capacity to ω-hydroxylate medium chain fatty acids (MCFAs) but also to metabolize protoxic xenobiotics which are chemically unrelated (Baer and Rettie, 2006;Zhang et al, 2006;Edson and Rettie, 2013). One of these xenobiotics is 4-ipomeanol (4-IPO) 12; a substance produced by Ipomea batatas as defense mechanism when infected with the common mold Fusarium solani.…”

Section: Introductionmentioning

confidence: 99%

Ligand characterization of CYP4B1 isoforms modified for high-level expression inEscherichia coliand HepG2 cells

Roellecke

Jäger

Gyurov

et al. 2017

Protein Engineering, Design and Selection

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Human CYP4B1, a cytochrome P450 monooxygenase predominantly expressed in the lung, inefficiently metabolizes classical CYP4B1 substrates, such as the naturally occurring furan pro-toxin 4-ipomeanol (4-IPO). Highly active animal forms of the enzyme convert 4-IPO to reactive alkylating metabolite(s) that bind(s) to cellular macromolecules. By substitution of 13 amino acids, we restored the enzymatic activity of human CYP4B1 toward 4-IPO and this modified cDNA is potentially valuable as a suicide gene for adoptive T-cell therapies. In order to find novel pro-toxins, we tested numerous furan analogs in in vitro cell culture cytotoxicity assays by expressing the wildtype rabbit and variants of human CYP4B1 in human liver-derived HepG2 cells. To evaluate the CYP4B1 substrate specificities and furan analog catalysis, we optimized the N-terminal sequence of the CYP4B1 variants by modification/truncation and established their heterologous expression in Escherichia coli (yielding 70 and 800 nmol·l −1 of recombinant human and rabbit enzyme, respectively). Finally, spectral binding affinities and oxidative metabolism of the furan analogs by the purified recombinant CYP4B1 variants were analyzed: the naturally occurring perilla ketone was found to be the tightest binder to CYP4B1, but also the analog that was most extensively metabolized by oxidative processes to numerous non-reactive reaction products.

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Section: Introductionmentioning

confidence: 99%

Ligand characterization of CYP4B1 isoforms modified for high-level expression inEscherichia coliand HepG2 cells

Roellecke

Jäger

Gyurov

et al. 2017

Protein Engineering, Design and Selection

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“…It is estimated that roughly 15% of fatty acids undergo -hydroxylation during peak periods of fatty acid catabolism (4), whereas this fraction is much smaller under conditions where concentrations of nonesterified fatty acids are low (5). Collectively, these enzymes provide pathways for the metabolic clearance of branched chain fatty acids, eicosanoids, and xenobiotic substrates such as dietary phytanic acid, drugs, toxins, and vitamins E and K (1,2,6).…”

mentioning

confidence: 99%

“…Within human family 4 cytochrome P450 enzymes, the capacity for -hydroxylation is associated with a substitution of glutamic acid for the first alanine or glycine in the canonical sequence motif, (A/G)GX(D/E)T (6). This sequence motif is located on helix I in the active site near the heme iron.…”

mentioning

confidence: 99%

The Crystal Structure of Cytochrome P450 4B1 (CYP4B1) Monooxygenase Complexed with Octane Discloses Several Structural Adaptations for ω-Hydroxylation

Hsu

Baer

Rettie

et al. 2017

Journal of Biological Chemistry

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Edited by Ruma BanerjeeP450 family 4 fatty acid -hydroxylases preferentially oxygenate primary C-H bonds over adjacent, energetically favored secondary C-H bonds, but the mechanism explaining this intriguing preference is unclear. To this end, the structure of rabbit P450 4B1 complexed with its substrate octane was determined by X-ray crystallography to define features of the active site that contribute to a preference for -hydroxylation. The structure indicated that octane is bound in a narrow active-site cavity that limits access of the secondary C-H bond to the reactive intermediate. A highly conserved sequence motif on helix I contributes to positioning the terminal carbon of octane for -hydroxylation. Glu-310 of this motif auto-catalytically forms an ester bond with the heme 5-methyl, and the immobilized Glu-310 contributes to substrate positioning. The preference for -hydroxylation was decreased in an E310A mutant having a shorter side chain, but the overall rates of metabolism were retained. E310D and E310Q substitutions having longer side chains exhibit lower overall rates, likely due to higher conformational entropy for these residues, but they retained high preferences for octane -hydroxylation. Sequence comparisons indicated that active-site residues constraining octane for -hydroxylation are conserved in family 4 P450s. Moreover, the heme 7-propionate is positioned in the active site and provides additional restraints on substrate binding. In conclusion, P450 4B1 exhibits structural adaptations for -hydroxylation that include changes in the conformation of the heme and changes in a highly conserved helix I motif that is associated with selective oxygenation of unactivated primary C-H bonds.Cytochrome P450 family 4 fatty acid -hydroxylases are heme-containing monooxygenases that provide pathways for the reduction of potentially toxic non-esterified fatty acids and for the elimination of excess nutritive and non-nutritive lipids by catalyzing the addition of oxygen to a C-H bond of the terminal -carbon of fatty acids (1, 2). The resulting -alcohols are generally oxidized further to produce dicarboxylic acids, but they also may be transformed to glucuronides or esterified to glycerolipids. Urinary dicarboxylic fatty acids are elevated in humans by fasting or in uncontrolled diabetes, which are conditions where adipocyte lipolysis increases the availability of non-esterified fatty acids to fuel metabolism (3). It is estimated that roughly 15% of fatty acids undergo -hydroxylation during peak periods of fatty acid catabolism (4), whereas this fraction is much smaller under conditions where concentrations of nonesterified fatty acids are low (5). Collectively, these enzymes provide pathways for the metabolic clearance of branched chain fatty acids, eicosanoids, and xenobiotic substrates such as dietary phytanic acid, drugs, toxins, and vitamins E and K (1, 2, 6).Similar to other P450 2 gene families encoding multipurpose enzymes for the elimination of xenobiotic compounds, family 4 exhibits genetic diversi...

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“…Interestingly, congenic male and female hemizygote line B 129/Sv mice carrying two CYP4A11 gene copies on one haploid chromosome (B Ϫ/ϩ ) displayed normal BP of 111 Ϯ 6 mm Hg (n ϭ 13), and the independent congenic hemizygous CYP4A11 transgenic line F 129/Sv male mice that carry only one copy of the CYP4A11 gene (F Ϫ/ϩ ) also exhibited normal BP (107 Ϯ 11 mm Hg, n ϭ 8). Treatment of hypertensive B-129/Sv-4A11 ϩ/ϩ mice with HET0016, a selective inhibitor of fatty acid -hydroxylases (including CYP4A11 (28,29)) normalized BP, and after administration of HET0016 was discontinued, BP returned to the elevated levels observed before treatment (Fig. 1C).…”

Section: Increased Systemic Bp In B-129/sv-4a11mentioning

confidence: 92%

20-Hydroxyeicosatetraenoic Acid (HETE)-dependent Hypertension in Human Cytochrome P450 (CYP) 4A11 Transgenic Mice

Savas

Wei

Hsu

et al. 2016

Journal of Biological Chemistry

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CYP4 Enzymes As Potential Drug Targets: Focus on Enzyme Multiplicity, Inducers and Inhibitors, and Therapeutic Modulation of 20- Hydroxyeicosatetraenoic Acid (20-HETE) Synthase and Fatty Acid ω- Hydroxylase Activities

Cited by 87 publications

References 92 publications

Ligand characterization of CYP4B1 isoforms modified for high-level expression inEscherichia coliand HepG2 cells

Ligand characterization of CYP4B1 isoforms modified for high-level expression inEscherichia coliand HepG2 cells

The Crystal Structure of Cytochrome P450 4B1 (CYP4B1) Monooxygenase Complexed with Octane Discloses Several Structural Adaptations for ω-Hydroxylation

20-Hydroxyeicosatetraenoic Acid (HETE)-dependent Hypertension in Human Cytochrome P450 (CYP) 4A11 Transgenic Mice

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