Cytochrome P450 4F subfamily: at the crossroads of eicosanoid and drug metabolism

The fatty acid omega hydroxylase genes (CYP4 family) in the progression of metabolic dysfunction-associated steatotic liver disease (MASLD): An RNA sequence database analysis and review

Fatty acid omega hydroxylase P450s consist of enzymes that hydroxylate various chain-length saturated and unsaturated fatty acids (FAs) and bioactive eicosanoid lipids. The human cytochrome P450 gene 4 family (CYP4) consists of 12 members that are associated with several human diseases. However, their role in the progression of metabolic dysfunction-associated fatty liver disease (MASLD) remains largely unknown. It has long been thought that the induction of CYP4 family P450 during fasting and starvation prevents FA-related lipotoxicity through FA metabolism to dicarboxylic acids that are chain-shortened in peroxisomes and then transported to the mitochondria for complete oxidation. Several studies have revealed that peroxisome succinate transported to the mitochondria is used for gluconeogenesis during fasting and starvation, and recent evidence suggests that peroxisome acetate can be utilized for lipogenesis and lipid droplet formation as well as epigenetic modification of gene transcription. In addition, omega hydroxylation of the bioactive eicosanoid arachidonic acid to 20-Hydroxyeicosatetraenoic acid (20-HETE) is essential for activating the GPR75 receptor, leading to vasoconstriction and cell proliferation. Several mouse models of diet-induced MASLD have revealed the induction of selective CYP4A members and the suppression of CYP4F during steatosis and steatohepatitis, suggesting a critical metabolic role in the progression of fatty liver disease. Thus, to further investigate the functional roles of CYP4 genes, we analyzed the differential gene expression of 12 members of CYP4 gene family in datasets from the Gene Expression Omnibus (GEO) from patients with steatosis, steatohepatitis, fibrosis, cirrhosis, and hepatocellular carcinoma. We also observed the differential expression of various CYP4 genes in the progression of MASLD, indicating that different CYP4 members may have unique functional roles in the metabolism of specific FAs and eicosanoids at various stages of fatty liver disease. These results suggest that targeting selective members of the CYP4A family is a viable therapeutic approach for treating and managing MASLD.

Real time changes in the expression of eicosanoid synthesizing enzymes during inflammation

Immune responses during inflammation involve complex, well-coordinated lipid signaling pathways. Eicosanoids are a class of lipid signaling molecules derived from polyunsaturated fatty acids such as arachidonic acid and constitute a major network that controls inflammation and its subsequent resolution. Arachidonic acid is metabolized by enzymes in three different pathways to form a variety of lipid metabolites that can be either pro- or anti-inflammatory. Therefore, an understanding of the time-dependent gene expression, lipid metabolite profiles and cytokine profiles during the initial inflammatory response is necessary, as it will allow for the design of time-dependent therapeutics. Herein, we investigate the multi-level regulation of this process. After stimulating RAW 264.7 cells, a mouse-derived macrophage cell line commonly used to examine inflammatory responses, we examine the gene expression of 44 relevant lipid metabolizing enzymes from the different eicosanoid synthesizing classes. We also measure the formation of lipid metabolites and production of cytokines at selected time points. Results reveal a dynamic relationship between the time-course of inflammation dependent gene expression of the three eicosanoid synthesizing enzymes.

Functional Characterization of 29 Cytochrome P450 4F2 Variants Identified in a Population of 8380 Japanese Subjects and Assessment of Arachidonic Acid ω-Hydroxylation

Cytochrome P450 4F2 (CYP4F2) is an enzyme that is involved in the metabolism of arachidonic acid (AA), vitamin E and K, and xenobiotics including drugs. CYP4F2*3 polymorphism (rs2108622; c.1297G>A; p.Val433Met) has been associated with hypertension, ischemic stroke, and variation in the effectiveness of the anticoagulant drug warfarin. In this study, we characterized wild-type CYP4F2 and 28 CYP4F2 variants, including a Val433Met substitution, detected in 8380 Japanese subjects. The CYP4F2 variants were heterologously expressed in 293FT cells to measure the concentrations of CYP4F2 variant holoenzymes using carbon monoxide-reduced difference spectroscopy, where the wild type and 18 holoenzyme variants showed a peak at 450 nm. Kinetic parameters [Vmax , substrate concentration producing half of Vmax (S50 ), and intrinsic clearance (CL int ) as Vmax /S50 ] of AA ω-hydroxylation were determined for the wild type and 21 variants with enzyme activity. Compared with the wild type, two variants showed significantly decreased CL int values for AA ω-hydroxylation. The values for seven variants could not be determined because no enzymatic activity was detected at the highest substrate concentration used. Three-dimensional structural modeling was performed to determine the reason for reduced enzymatic activity of the CYP4F2 variants. Our findings contribute to a better understanding of CYP4F2 variant-associated diseases and possible future therapeutic strategies. SIGNIFICANCE STATEMENT: CYP4F2 is involved in the metabolism of arachidonic acid and vitamin K, and CYP4F2*3 polymorphisms have been associated with hypertension and variation in the effectiveness of the anticoagulant drug warfarin. This study presents a functional analysis of 28 CYP4F2 variants identified in Japanese subjects, demonstrating that seven gene polymorphisms cause loss of CYP4F2 function, and proposes structural changes that lead to altered function.

The biochemistry and physiology of long-chain dicarboxylic acid metabolism

Mitochondrial β-oxidation is the most prominent pathway for fatty acid oxidation but alternative oxidative metabolism exists. Fatty acid ω-oxidation is one of these pathways and forms dicarboxylic acids as products. These dicarboxylic acids are metabolized through peroxisomal β-oxidation representing an alternative pathway, which could potentially limit the toxic effects of fatty acid accumulation. Although dicarboxylic acid metabolism is highly active in liver and kidney, its role in physiology has not been explored in depth. In this review, we summarize the biochemical mechanism of the formation and degradation of dicarboxylic acids through ω- and β-oxidation, respectively. We will discuss the role of dicarboxylic acids in different (patho)physiological states with a particular focus on the role of the intermediates and products generated through peroxisomal β-oxidation. This review is expected to increase the understanding of dicarboxylic acid metabolism and spark future research.

Exploring human CYP4 enzymes: physiological roles, function in diseases and focus on inhibitors

The cytochrome P450 (CYP)4 family of enzymes are monooxygenases responsible for the ω-oxidation of endogenous fatty acids and eicosanoids and play a crucial part in regulating numerous eicosanoid signaling pathways. Recently, CYP4 gained attention as a potential therapeutic target for several human diseases, including cancer, cardiovascular diseases and inflammation. Small-molecule inhibitors of CYP4 could provide promising treatments for these diseases. The aim of the present review is to highlight the advances in the field of CYP4, discussing the physiology and pathology of the CYP4 family and compiling CYP4 inhibitors into groups based on their chemical classes to provide clues for the future discovery of drug candidates targeting CYP4. Teaser: This review provides an updated view of the physiology and pathology of CYP4 enzymes. CYP4 inhibitors are compiled based on their skeletons to provide clues for the future discovery of drug candidates targeting CYP4.

Regulation of Human Endogenous Metabolites by Drug Transporters and Drug Metabolizing Enzymes: An Analysis of Targeted SNP-Metabolite Associations

Drug transporters and drug-metabolizing enzymes are primarily known for their role in the absorption, distribution, metabolism, and excretion (ADME) of small molecule drugs, but they also play a key role in handling endogenous metabolites. Recent cross-tissue co-expression network analyses have revealed a "Remote Sensing and Signaling Network" of multispecific, oligo-specific, and monospecific transporters and enzymes involved in endogenous metabolism. This includes many proteins from families involved in ADME (e.g., SLC22, SLCO, ABCC, CYP, UGT). Focusing on the gut-liver-kidney axis, we identified the endogenous metabolites potentially regulated by this network of ~1000 proteins by associating SNPs in these genes with the circulating levels of thousands of small, polar, bioactive metabolites, including free fatty acids, eicosanoids, bile acids, and other signaling metabolites that act in part via G-protein coupled receptors (GPCRs), nuclear receptors, and kinases. We identified 77 genomic loci associated with 7236 unique metabolites. This included metabolites that were associated with multiple, distinct loci, indicating coordinated regulation between multiple genes (including drug transporters and drug-metabolizing enzymes) of specific metabolites. We analyzed existing pharmacogenomic data and noted SNPs implicated in endogenous metabolite handling (e.g., rs4149056 in SLCO1B1) also affecting drug ADME. The overall results support the existence of close relationships, via interactions with signaling metabolites, between drug transporters and drug-metabolizing enzymes that are part of the Remote Sensing and Signaling Network, and with GPCRs and nuclear receptors. These analyses highlight the potential for drug-metabolite interactions at the interfaces of the Remote Sensing and Signaling Network and the ADME protein network.

The Functions of Cytochrome P450 ω-hydroxylases and the Associated Eicosanoids in Inflammation-Related Diseases

The cytochrome P450 (CYP) ω-hydroxylases are a subfamily of CYP enzymes. While CYPs are the main metabolic enzymes that mediate the oxidation reactions of many endogenous and exogenous compounds in the human body, CYP ω-hydroxylases mediate the metabolism of multiple fatty acids and their metabolites via the addition of a hydroxyl group to the ω- or (ω-1)-C atom of the substrates. The substrates of CYP ω-hydroxylases include but not limited to arachidonic acid, docosahexaenoic acid, eicosapentaenoic acid, epoxyeicosatrienoic acids, leukotrienes, and prostaglandins. The CYP ω-hydroxylases-mediated metabolites, such as 20-hyroxyleicosatrienoic acid (20-HETE), 19-HETE, 20-hydroxyl leukotriene B4 (20-OH-LTB₄), and many ω-hydroxylated prostaglandins, have pleiotropic effects in inflammation and many inflammation-associated diseases. Here we reviewed the classification, tissue distribution of CYP ω-hydroxylases and the role of their hydroxylated metabolites in inflammation-associated diseases. We described up-regulation of CYP ω-hydroxylases may be a pathogenic mechanism of many inflammation-associated diseases and thus CYP ω-hydroxylases may be a therapeutic target for these diseases. CYP ω-hydroxylases-mediated eicosanods play important roles in inflammation as pro-inflammatory or anti-inflammatory mediators, participating in the process stimulated by cytokines and/or the process stimulating the production of multiple cytokines. However, most previous studies focused on 20-HETE,and further studies are needed for the function and mechanisms of other CYP ω-hydroxylases-mediated eicosanoids. We believe that our studies of CYP ω-hydroxylases and their associated eicosanoids will advance the translational and clinal use of CYP ω-hydroxylases inhibitors and activators in many diseases.

A Review of Oxidative Stress Products and Related Genes in Early Alzheimer's Disease

Oxidative stress is associated with the progression of Alzheimer’s disease (AD). Reactive oxygen species can modify lipids, DNA, RNA, and proteins in the brain. The products of their peroxidation and oxidation are readily detectable at incipient stages of disease. Based on these oxidation products, various biomarker-based strategies have been developed to identify oxidative stress levels in AD. Known oxidative stress-related biomarkers include lipid peroxidation products F2-isoprostanes, as well as malondialdehyde and 4-hydroxynonenal which both conjugate to specific amino acids to modify proteins, and DNA or RNA oxidation products 8-hydroxy-2’-deoxyguanosine (8-OHdG) and 8-hydroxyguanosine (8-OHG), respectively. The inducible enzyme heme oxygenase type 1 (HO-1) is found to be upregulated in response to oxidative stress-related events in the AD brain. While these global biomarkers for oxidative stress are associated with early-stage AD, they generally poorly differentiate from other neurodegenerative disorders that also coincide with oxidative stress. Redox proteomics approaches provided specificity of oxidative stress-associated biomarkers to AD pathology by the identification of oxidatively damaged pathology-specific proteins. In this review, we discuss the potential combined diagnostic value of these reported biomarkers in the context of AD and discuss eight oxidative stress-related mRNA biomarkers in AD that we newly identified using a transcriptomics approach. We review these genes in the context of their reported involvement in oxidative stress regulation and specificity for AD. Further research is warranted to establish the protein levels and their functionalities as well as the molecular mechanisms by which these potential biomarkers are involved in regulation of oxidative stress levels and their potential for determination of oxidative stress and disease status of AD patients.

Polymorphisms in genes related to oxidative stress and inflammation: Emerging links with the pathogenesis and severity of Cerebral Cavernous Malformation disease

Cerebral Cavernous Malformation (CCM) is a cerebrovascular disease of genetic origin affecting 0.5% of the population and characterized by abnormally enlarged and leaky capillaries that predispose to seizures, neurological deficits, and intracerebral hemorrhage (ICH). CCM occurs sporadically or is inherited as dominant condition with incomplete penetrance and highly variable expressivity. Three disease genes have been identified: KRIT1 (CCM1), CCM2 and CCM3. Previous results demonstrated that loss-of-function mutations of CCM genes cause pleiotropic effects, including defective autophagy, altered reactive oxygen species (ROS) homeostasis, and enhanced sensitivity to oxidative stress and inflammatory events, suggesting a novel unifying pathogenetic mechanism, and raising the possibility that CCM disease onset and severity are influenced by the presence of susceptibility and modifier genes. Consistently, genome-wide association studies (GWAS) in large and homogeneous cohorts of patients sharing the familial form of CCM disease and identical mutations in CCM genes have led to the discovery of distinct genetic modifiers of major disease severity phenotypes, such as development of numerous and large CCM lesions, and susceptibility to ICH. This review deals with the identification of genetic modifiers with a significant impact on inter-individual variability in CCM disease onset and severity, including highly polymorphic genes involved in oxidative stress, inflammatory and immune responses, such as cytochrome P450 monooxygenases (CYP), matrix metalloproteinases (MMP), and Toll-like receptors (TLR), pointing to their emerging prognostic value, and opening up new perspectives for risk stratification and personalized medicine strategies.

Molecular and Structural Evolution of Cytochrome P450 Aromatase

Aromatase is the cytochrome P450 enzyme converting androgens into estrogen in the last phase of steroidogenesis. As estrogens are crucial in reproductive biology, aromatase is found in vertebrates and the invertebrates of the genus Branchiostoma, where it carries out the aromatization reaction of the A-ring of androgens that produces estrogens. Here, we investigate the molecular evolution of this unique and highly substrate-selective enzyme by means of structural, sequence alignment, and homology modeling, shedding light on its key role in species conservation. The alignments led to the identification of a core structure that, together with key and unique amino acids located in the active site and the substrate recognition sites, has been well conserved during evolution. Structural analysis shows what their roles are and the reason why they have been preserved. Moreover, the residues involved in the interaction with the redox partner and some phosphorylation sites appeared late during evolution. These data reveal how highly substrate-selective cytochrome P450 has evolved, indicating that the driving forces for evolution have been the optimization of the interaction with the redox partner and the introduction of phosphorylation sites that give the possibility of modulating its activity in a rapid way.

Regulation of cytochrome P450 4F11 expression by liver X receptor alpha

Cytochrome P450 4F (CYP4F) enzymes are responsible for the metabolism of eicosanoids, which play important roles in inflammation. Nuclear receptor liver X receptor alpha (LXRα) is a critical signal node connecting inflammation and lipid metabolism. Studies revealed that the release of cytokines and nuclear factor-κB (NF-κB) can change the CYP4F11 expression in HepG2 cells. However, the effect of LXRα on the CYP4F family and the underlying mechanism remain unclear. This study found that CYP4F11 is a target gene of LXRα. Luciferase assays and siRNA transfection showed that LXRα increased the transcription of CYP4F11 and LXRα agonist GW3965 could induce the expression of CYP4F11 by activating the LXRα-CYP4F11 pathway. Besides, overexpression of CYP4F11 could decrease TNF-α and IL-1β in lipopolysaccharide (LPS)-induced THP-1 cells. The finding of the regulation of CYP4F11 may contribute to the anti-inflammatory activity of LXRα agonists.

Comparative transcriptome analysis of the fungus Gibberella zeae transforming lithocholic acid into ursodeoxycholic acid

The comparative transcriptome analysis of the fungus Gibberella zeae which could efficiently catalyze the 7β-hydroxylation of LCA to produce UDCA was performed with LCA induction. This is the first time to report the comparative transcriptome of fungus under LCA treatment. Totally, 1364 differentially expressed genes including 770 up-regulated and 594 down-regulated genes were identified. In the 770 up-regulated genes, 12 genes with the function of hydroxylation were picked out by application of function screening, which were annotated as CYP450 or hydroxylase. Moreover, the qRT-PCR results of five up-regulated CYP450-like genes confirmed the credibility of RNA-Seq further. These results provide valuable information for the discovery of novel enzyme producing clinical drug UDCA from butchery byproduct LCA, and also might indicate some clues for the detoxification process of LCA in humans.

CYP2J2 Molecular Recognition: A New Axis for Therapeutic Design

Cytochrome P450 (CYP) epoxygenases are a special subset of heme-containing CYP enzymes capable of performing the epoxidation of polyunsaturated fatty acids (PUFA) and the metabolism of xenobiotics. This dual functionality positions epoxygenases along a metabolic crossroad. Therefore, structure-function studies are critical for understanding their role in bioactive oxy-lipid synthesis, drug-PUFA interactions, and for designing therapeutics that directly target the epoxygenases. To better exploit CYP epoxygenases as therapeutic targets, there is a need for improved understanding of epoxygenase structure-function. Of the characterized epoxygenases, human CYP2J2 stands out as a potential target because of its role in cardiovascular physiology. In this review, the early research on the discovery and activity of epoxygenases is contextualized to more recent advances in CYP epoxygenase enzymology with respect to PUFA and drug metabolism. Additionally, this review employs CYP2J2 epoxygenase as a model system to highlight both the seminal works and recent advances in epoxygenase enzymology. Herein we cover CYP2J2's interactions with PUFAs and xenobiotics, its tissue-specific physiological roles in diseased states, and its structural features that enable epoxygenase function. Additionally, the enumeration of research on CYP2J2 identifies the future needs for the molecular characterization of CYP2J2 to enable a new axis of therapeutic design.

CYP4F13 is the Major Enzyme for Conversion of alpha-Eleostearic Acid into cis-9, trans-11-Conjugated Linoleic Acid in Mouse Hepatic Microsomes

Our previous studies have shown that α-eleostearic acid (α-ESA; cis-9, trans-11, trans-13 (c9,t11,t13)-conjugated linolenic acid (CLnA)) is converted into c9,t11-conjugated linoleic acid (CLA) in rats. Furthermore, we have demonstrated that the conversion of α-ESA into CLA is a nicotinamide adenine dinucleotide phosphate (NADPH)-dependent enzymatic reaction, which occurs mostly in the rat liver. However, the precise metabolic pathway and enzyme involved have not been identified yet. Therefore, in this study we aimed to determine the role of cytochrome P450 (CYP) in the conversion of α-ESA into c9,t11-CLA using an in vitro reconstitution system containing mouse hepatic microsomes, NADPH, and α-ESA. The CYP4 inhibitors, 17-ODYA and HET0016, performed the highest level of inhibition of CLA formation. Furthermore, the redox partner cytochrome P450 reductase (CPR) inhibitor, 2-chloroethyl ethyl sulfide (CEES), also demonstrated a high level of inhibition. Thus, these results indicate that the NADPH-dependent CPR/CYP4 system is responsible for CLA formation. In a correlation analysis between the specific activity of CLA formation and Cyp4 family gene expression in tissues, Cyp4a14 and Cyp4f13 demonstrated the best correlations. However, the CYP4F substrate prostaglandin A₁ (PGA₁) exhibited the strongest inhibitory effect on CLA formation, while the CYP4A and CYP4B1 substrate lauric acid had no inhibitory effect. Therefore, we conclude that the CYP4F13 enzyme is the major enzyme involved in CLA formation. This pathway is a novel pathway for endogenous CLA synthesis, and this study provides insight into the potential application of CLnA in functional foods.

Farnesoid X receptor activation induces the degradation of hepatotoxic 1-deoxysphingolipids in non-alcoholic fatty liver disease

BACKGROUND & AIMS

Patients with non-alcoholic fatty liver disease (NAFLD) exhibit higher levels of plasma 1-deoxysphingolipids than healthy individuals. The aim of this study was to investigate the role of farnesoid X receptor (FXR) in 1-deoxysphingolipid de novo synthesis and degradation.

METHODS

Mice were fed with a high-fat diet (HFD) to induce obesity and NAFLD, and then treated with the FXR ligand obeticholic acid (OCA). Histology and gene expression analysis were performed on liver tissue. Sphingolipid patterns from NAFLD patients and mouse models were assessed by liquid chromatography-mass spectrometry. The molecular mechanism underlying the effect of FXR activation on sphingolipid metabolism was studied in Huh7 cells and primary cultured hepatocytes, as well as in a 1-deoxysphinganine-treated mouse model.

RESULTS

1-deoxysphingolipids were increased in both NAFLD patients and mouse models. FXR activation by OCA protected the liver against oxidative stress, apoptosis, and reduced 1-deoxysphingolipid levels, both in a HFD-induced mouse model of obesity and in 1-deoxysphinganine-treated mice. In vitro, FXR activation lowered intracellular 1-deoxysphingolipid levels by inducing Cyp4f-mediated degradation, but not by inhibiting de novo synthesis, thereby protecting hepatocytes against doxSA-induced cytotoxicity, mitochondrial damage, and apoptosis. Overexpression of Cyp4f13 in cells was sufficient to ameliorate doxSA-induced cytotoxicity. Treatment with the Cyp4f pan-inhibitor HET0016 or FXR knock-down fully abolished the protective effect of OCA, indicating that OCA-mediated 1-deoxysphingolipid degradation is FXR and Cyp4f dependent.

CONCLUSIONS

Our study identifies FXR-Cyp4f as a novel regulatory pathway for 1-deoxysphingolipid metabolism. FXR activation represents a promising therapeutic strategy for patients with metabolic syndrome and NAFLD.

mRNA levels of drug-metabolizing enzymes in 11 brain regions of cynomolgus macaques

The cynomolgus macaque is an important nonhuman primate species in drug metabolism studies, in part because of its evolutionary closeness to humans. Cytochromes P450 (P450s) have been investigated in the major drug-metabolizing organs, i.e., the liver and small intestine, but have not been fully investigated in the brain. However, recent investigations have indicated possible important roles for P450s in the brain. In this study, by using the quantitative polymerase chain reaction, we measured the mRNA levels of 38 cynomolgus drug-metabolizing enzymes, including 19 P450s, 10 UDP-glycosyltransferases, and 9 other enzymes, in 11 brain regions. Among these drug-metabolizing enzymes, expression of 32 enzyme mRNAs were detected in one or more brain regions, indicating their possible roles in the brain. Further investigation of metabolic activities would facilitate better understanding of the importance of these enzymes in the brain.

Air-liquid interface culture changes surface properties of A549 cells

A549 cells are common models in the assessment of respiratory cytotoxicity. To provide physiologically more representative exposure conditions and increase the differentiation state, respiratory cells, for instance Calu-3 bronchial epithelial cells, are cultured at an air-liquid interface (ALI). There are indications that A549 cells also change their phenotype upon culture in ALI. The influence of culture in two variations of transwell cultures compared to conventional culture in plastic wells on the phenotype of A549 cells was studied. Cells were characterized by morphology, proliferation and transepithelial electrical resistance, whole genome transcription analysis, Western blot and immunocytochemical detection of pro-surfactant proteins. Furthermore, lipid staining, surface morphology, cell elasticity, surface tension and reaction to quartz particles were performed. Relatively small changes were noted in the expression of differentiation markers for alveolar cells but A549 cells cultured in ALI showed marked differences in lipid staining and surface morphology, surface tension and cytotoxicity of quartz particles. Data show that changes in physiological reactions of A549 cells in ALI culture were rather caused by change of surface properties than by increased expression of surfactant proteins.

The impact of CYP2C19 and CYP4F2 variants and clinical factors on treatment outcomes during antiplatelet therapy

Aim: The aim of this study was to determine the impact of genetic and nongenetic factors on treatment outcomes in patients receiving dual antiplatelet therapy after percutaneous coronary intervention and stent implantation. Materials & methods: Patients (n = 628) used clopidogrel or ticagrelor for at least 1 week before platelet aggregation test. Results: Multivariate binary regression analysis demonstrated that aspirin use and CYP4F2 T allele significantly increased odds for bleeding in clopidogrel users (OR: 2.488, 95% CI: 1.452-4.265; p = 0.001 and OR: 1.573, 95% CI: 1.066-2.320; respectively; p = 0.022). CYP4F2 T allele significantly increased odds for bleeding in ticagrelor users (OR: 8.270, 95% CI: 3.917-17.462; p < 0.001). Conclusion: Aspirin use and CYP4F2 T allele were significantly associated with bleeding during dual antiplatelet therapy.

Effects of Ketoconazole, a CYP4F2 Inhibitor, and CYP4F2*3 Genetic Polymorphism on Pharmacokinetics of Vitamin K1

The objective of this study was to evaluate whether cytochrome P450 (CYP)4F2 is involved in the exposure of vitamin K₁ through a drug interaction study with ketoconazole, a CYP4F2 inhibitor, and a pharmacogenetic study with CYP4F2*3. Twenty-one participants with different CYP4F2*3 polymorphisms were enrolled (8 for *1/*1, 7 for *1/*3, and 6 for *3/*3). All participants were treated twice daily for 5 days with 200 mg of ketoconazole or placebo. Finally, a single dose of 10 mg vitamin K₁ was administered, plasma levels of vitamin K₁ were measured, and its pharmacokinetics was assessed. Ketoconazole elevated the plasma levels of vitamin K₁ and increased the average area under the concentration-time curve (AUC_inf ) and peak concentration by 41% and 40%, respectively. CYP4F2*3 polymorphism also affected plasma levels of vitamin K₁ and its pharmacokinetics in a gene dose-dependent manner. The average AUC_inf value was 659.8 ng·h/mL for CYP4F2*1/*1, 878.1 ng·h/mL for CYP4F2*1/*3, and 1125.2 ng·h/mL for CYP4F2*3/*3 (P = .010). This study revealed that ketoconazole and CYP4F2*3 polymorphism substantially increased the exposure of vitamin K₁ in humans. These findings provide a plausible explanation for variations in warfarin dose requirements resulting from interindividual variations in vitamin K₁ exposure due to CYP4F2-related drug interactions and genetic polymorphisms.

Polyunsaturated fatty acid metabolites: biosynthesis in Leishmania and role in parasite/host interaction

Inside the human host, Leishmania infection starts with phagocytosis of infective promastigotes by macrophages. In order to survive, Leishmania has developed several strategies to manipulate macrophage functions. Among these strategies, Leishmania as a source of bioactive lipids has been poorly explored. Herein, we assessed the biosynthesis of polyunsaturated fatty acid metabolites by infective and noninfective stages of Leishmania and further explored the role of these metabolites in macrophage polarization. The concentration of docosahexaenoic acid metabolites, precursors of proresolving lipid mediators, was increased in the infective stage of the parasite compared with the noninfective stage, and cytochrome P450-like proteins were shown to be implicated in the biosynthesis of these metabolites. The treatment of macrophages with lipids extracted from the infective forms of the parasite led to M2 macrophage polarization and blocked the differentiation into the M1 phenotype induced by IFN-γ. In conclusion, Leishmania polyunsaturated fatty acid metabolites, produced by cytochrome P450-like protein activity, are implicated in parasite/host interactions by promoting the polarization of macrophages into a proresolving M2 phenotype.

iTRAQ-based proteomic profiling of Pycnoporus sanguineus in response to co-existed tetrabromobisphenol A (TBBPA) and hexavalent chromium

In current study, we investigated the changes of proteome profiles of Pycnoporus sanguineus after a single exposure of Cr(VI), TBBPA and a combined exposure of TBBPA and Cr(VI), with the goal of illuminating the cellular mechanisms involved in the interactions of co-existed TBBPA and Cr(VI) with the cells of P. sanguineus at the protein level. The results revealed that some ATP-binding cassette (ABC) transporters were obviously induced by these pollutants to accelerate the transportation, transformation and detoxification of TBBPA and Cr(VI). Cr(VI) could inhibit the bioremoval of its organic co-pollutants TBBPA through suppressing the expression of several key proteins related to the metabolism of TBBPA by P. sanguineus, including two cytochrome P450s, pentachlorophenol 4-monooxygenase and glutathione S-transferases. Furthermore, Cr(VI) possibly reduced the cell vitality and growth of P. sanguineus by enhancing the expression of imidazole glycerol phosphate synthase as well as by decreasing the abundances of proteins associated with the intracellular metabolic processes, such as the tricarboxylic acid cycle, purine metabolism and glutathione biosynthesis, thereby adversely affecting the biotransformation of TBBPA. Cr(VI) also inhibited the expression of peptidyl prolyl cis/trans isomerases, thus causing the damage of cell membrane integrity. In addition, some important proteins participated in the resistance to Cr(VI) toxicity were observed to up-regulate, including heat shock proteins, 26S proteasome, peroxiredoxins and three critical proteins implicated in S-adenosyl methionine synthesis, which contributed to reducing the hazard of Cr(VI) to P. sanguineus. The results of this study provide novel insights into the physiological responses and molecular mechanism of white rot fungi P. sanguineus to the stress of concomitant TBBPA and Cr(VI).

The arachidonic acid monooxygenase: from biochemical curiosity to physiological/pathophysiological significance

The initial studies of the metabolism of arachidonic acid (AA) by the cytochrome P450 (P450) hemeproteins sought to: a) elucidate the roles for these enzymes in the metabolism of endogenous pools of the FA, b) identify the P450 isoforms involved in AA epoxidation and ω/ω-1 hydroxylation, and c) explore the biological activities of their metabolites. These early investigations provided a foundation for subsequent efforts to establish the physiological relevance of the AA monooxygenase and its contributions to the pathophysiology of, for example, cancer, diabetes, hypertension, inflammation, nociception, and vascular disease. This retrospective analyzes the history of some of these efforts, with emphasis on genetic studies that identified roles for the murine Cyp4a and Cyp2c genes in renal and vascular physiology and the pathophysiology of hypertension and cancer. Wide-ranging investigations by laboratories worldwide, including the authors, have established a better appreciation of the enzymology, genetics, and physiologic roles for what is now known as the third branch of the AA cascade. Combined with the development of analytical and pharmacological tools, including robust synthetic agonists and antagonists of the major metabolites, we stand at the threshold of novel therapeutic approaches for the treatment of renal injury, pain, hypertension, and heart disease.

Transcriptome and Resistance-Related Genes Analysis of Botrytis cinerea B05.10 Strain to Different Selective Pressures of Cyprodinil and Fenhexamid

The pathogen Botrytis cinerea is a very dangerous pathogen that infects many economically important crops such as grape, strawberry, tomato, and eggplant. Cyprodinil, a pyrimidine amine fungicide, and fenhexamid, an amide fungicide, are new reagents for controlling gray mold with special efficacy. It is necessary to understand the change trends in the toxicological and physiological characteristics of B. cinerea with successive selective pressures of cyprodinil and fenhexamid to elongate the serving life of these fungicides for effective disease control. The toxicities of cyprodinil and fenhexamid at successive concentrations of EC25, EC50 and EC75 on B. cinerea strain BO5.10 were assayed along with mycelial growth-inhibition capacity. The results showed that the EC50 value of the cyprodinil-treated F27 strain increased approximately 18-fold, whereas of which in the fenhexamid-treated F27 strain increased only 3-fold compared with that of the F0 strain. The conductivities and glycerinum contents of the strains resistant to cyprodinil and fenhexamid were obviously enhanced; in contrast, the oxalic acid contents were decreased compared with those in the F0 strain. The transcriptomes of the F27 control (T01), cyprodinil-treated (T02) and fenhexamid- treated (T03) strains were analyzed, and the expression levels of functional genes in the T02 and T03 strains were significantly increased compared with those in the T01 strain; these results were further validated using qRT-PCR. The results indicated that the relative expression of two genes encoding mixed-functional oxidases (MFOs) BC1G_16062 and BC1G_16084, two genes encoding transmembrane proteins BC1G_12366 and BC1G_13768, two genes encoding Zinc finger proteins BC1G_13764 and BC1G_10483,one gene encoding citrate synthase enzyme BC1G_09151, one gene encoding gluconolactonase BC1G_15612 in the T02 and T03 strains and one gene encoding lysophospholipids enzyme BC1G_04893 in the T3 strain increased substantially compared with that in the T1 strain (P < 0.01). Functional prediction analysis of upregulated gene expression and structural verification was also performed, and the results showed that BC1G_10483 was a ZnF_C2HC transcriptional regulator interacting with the Sp1 element of these genes to respond to the pressures from cyprodinil and fenhexamid. Our results could contribute to a better understanding of the resistance mechanism of B. cinerea against cyprodinil and fenhexamid.

CYP2J2 is the major enzyme in human liver microsomes responsible for hydroxylation of SYL-927, a novel and selective sphingosine 1-phosphate receptor 1 (S1P1 ) agonist

SYL-927, a novel and selective S1P₁ agonist, is transferred to its active phosphate for the regulation of lymphocyte recirculation. This in vitro metabolism study is to elucidate the P450-mediated oxidation pathway of SYL-927 in human liver microsomes (HLMs). The results demonstrated that the ω-1 hydroxylated metabolite SYL-927-M was formed after incubation of SYL-927 with HLMs. Recombinant human CYP1A1 and CYP2J2 can efficiently catalyse SYL-927-M formation, followed by markedly less substrate conversion with CYP1A2, CYP2C19 and CYP2D6. Inhibition studies with chemical inhibitors and antibodies suggested that arachidonic acid, the substrate of CYP2J2, and CYP2J2-specific antibody effectively inhibited the formation of SYL-927-M in HLMs whereas no significant inhibition was observed with the inhibitors for CYP1A1, CYP1A2, CYP2C9, CYP2C19, CYP2D6, CYP2E1 and CYP3A4, demonstrating that CYP2J2 was primarily responsible for the formation of SYL-927-M.

Profiling cytochrome P450 family 4 gene expression in human hepatocellular carcinoma

Cytochrome P450 family 4 (CYP4) enzymes are known as microsomal omega (ω)-hydroxylases that metabolize fatty acids, eicosanoids, vitamin D and carcinogens. Thus, CYP4 enzymes may influence tumor development and progression. The aim of the present study was to evaluate the CYP4 expression profile in hepatocellular carcinoma (HCC) and its clinical relevance. The present study obtained CYP4 mRNA expression data for 377 HCC cases from The Cancer Genome Atlas cohort and performed Kaplan‑Meier survival, Gene Ontology functional enrichment, and gene set enrichment analysis (GSEA). In addition, the level of CYP4F2 protein expression was evaluated in matched pairs of HCC and non‑tumor tissue samples and the results were correlated with the clinicopathological characteristics of HCC (n=113). HCC survival analyses indicated better overall survival in patients with high CYP4F2, CYP4F12 and CYP4V2 mRNA expression levels; the results for histological grade and Tumor‑Node‑Metastasis stage supported these results. GSEA revealed high levels of CYP4F2, CYP4F12 and CYP4V2 mRNA expression to be negatively correlated with the expression of cell cycle‑associated genes. CYP4F2 protein expression was higher in non‑neoplastic liver tissue than in HCC tissue and positively correlated with favorable pathological tumor stage (I vs. II‑IV; P=0.022) and was a good independent prognostic factor for overall survival (P=0.004). These results demonstrate that the expression levels of the genes CYP4F2, CYP4F12 and CYPV2 are favorable prognostic factors in HCC and suggest the potential predictive diagnostic and prognostic roles of CYP4F2, CYP4F12 and CYPV2 gene expression in HCC.

Involvement of CYP4F2 in the Metabolism of a Novel Monophosphate Ester Prodrug of Gemcitabine and Its Interaction Potential In Vitro

Compound-3 is an oral monophosphate prodrug of gemcitabine. Previous data showed that Compound-3 was more potent than gemcitabine and it was orally active in a tumor xenograft model. In the present study, the metabolism of Compound-3 was investigated in several well-known in vitro matrices. While relatively stable in human and rat plasma, Compound-3 demonstrated noticeable metabolism in liver and intestinal microsomes in the presence of NADPH and human hepatocytes. Compound-3 could also be hydrolyzed by alkaline phosphatase, leading to gemcitabine formation. Metabolite identification using accurate mass- and information-based scan techniques revealed that Compound-3 was subjected to sequential metabolism, forming alcohol, aldehyde and carboxylic acid metabolites, respectively. Results from reaction phenotyping studies indicated that cytochrome P450 4F2 (CYP4F2) was a key CYP isozyme involved in Compound-3 metabolism. Interaction assays suggested that CYP4F2 activity could be inhibited by Compound-3 or an antiparasitic prodrug pafuramidine. Because CYP4F2 is a key CYP isozyme involved in the metabolism of eicosanoids and therapeutic drugs, clinical relevance of drug-drug interactions mediated via CYP4F2 inhibition warrants further investigation.

Generation and phenotypic characterisation of a cytochrome P450 4x1 knockout mouse

Cytochrome P450 4x1 (Cyp4x1) is expressed at very high levels in the brain but the function of this protein is unknown. It has been hypothesised to regulate metabolism of fatty acids and to affect the activity of endocannabinoid signalling systems, which are known to influence appetite and energy metabolism. The objective of the present investigation was to determine the impact of Cyp4x1 on body weight and energy metabolism by developing a line of transgenic Cyp4x1-knock out mice. Mice were developed with a global knock-out of the gene; the full-length RNA was undetectable, and mice were viable and fertile. Both male and female Cyp4x1-knock out mice gained significantly more body weight on normal lab chow diet compared to control flox mice on the same genetic background. At necropsy, Cyp4x1-knock out male mice had significantly greater intra-abdominal fat deposits (P<0.01), and enlarged adipocytes. Metabolic rate and locomotor activity as inferred from VO₂ measures and crossing of infrared beams in metabolic cages were not significantly affected by the mutation in either gender. The respiratory exchange ratio was significantly decreased in male knock out mice (P<0.05), suggesting a greater degree of fat oxidation, consistent with their higher adiposity. When mice were maintained on a high fat diet, VO₂ was significantly decreased in both male and female Cyp4x1-knock out mice. We conclude that the Cyp4x1-knock out mouse strain demonstrates a mildly obese phenotype, consistent with the view that cytochrome P450 4x1 plays a role in regulating fat metabolism.

Nonalcoholic fatty liver disease impairs the cytochrome P-450-dependent metabolism of α-tocopherol (vitamin E)

This study aims to investigate in in vivo and in vitro models of nonalcoholic fatty liver disease (NAFLD) the enzymatic metabolism of α-tocopherol (vitamin E) and its relationship to vitamin E-responsive genes with key role in the lipid metabolism and detoxification of the liver. The experimental models included mice fed a high-fat diet combined or not with fructose (HFD+F) and HepG2 human hepatocarcinoma cells treated with the lipogenic agents palmitate, oleate or fructose. CYP4F2 protein, a cytochrome P-450 isoform with proposed α-tocopherol ω-hydroxylase activity, decreased in HFD and even more in HFD+F mice liver; this finding was associated with increased hepatic levels of α-tocopherol and decreased formation of the corresponding long-chain metabolites α-13-hydroxy and α-13-carboxy chromanols. A decreased expression was also observed for PPAR-γ and SREBP-1 proteins, two vitamin E-responsive genes with key role in lipid metabolism and CYP4F2 gene regulation. A transient activation of CYP4F2 gene followed by a repression response was observed in HepG2 cells during the exposure to increasing levels of the lipogenic and cytotoxic agent palmitic acid; such gene repression effect was further exacerbated by the co-treatment with oleic acid and α-tocopherol and was also observed for PPAR-γ and the SREBP isoforms 1 and 2. Such gene response was associated with increased uptake and ω-hydroxylation of α-tocopherol, which suggests a minor role of CYP4F2 in the enzymatic metabolism of vitamin E in HepG2 cells. In conclusion, the liver metabolism and gene response of α-tocopherol are impaired in experimental NAFLD.

The differential expression of omega-3 and omega-6 fatty acid metabolising enzymes in colorectal cancer and its prognostic significance

Background:

Colorectal cancer is a common malignancy and one of the leading causes of cancer-related deaths. The metabolism of omega fatty acids has been implicated in tumour growth and metastasis.

Methods:

This study has characterised the expression of omega fatty acid metabolising enzymes CYP4A11, CYP4F11, CYP4V2 and CYP4Z1 using monoclonal antibodies we have developed. Immunohistochemistry was performed on a tissue microarray containing 650 primary colorectal cancers, 285 lymph node metastasis and 50 normal colonic mucosa.

Results:

The differential expression of CYP4A11 and CYP4F11 showed a strong association with survival in both the whole patient cohort (hazard ratio (HR)=1.203, 95% CI=1.092–1.324, χ²=14.968, P=0.001) and in mismatch repair-proficient tumours (HR=1.276, 95% CI=1.095–1.488, χ²=9.988, P=0.007). Multivariate analysis revealed that the differential expression of CYP4A11 and CYP4F11 was independently prognostic in both the whole patient cohort (P=0.019) and in mismatch repair proficient tumours (P=0.046).

Conclusions:

A significant and independent association has been identified between overall survival and the differential expression of CYP4A11 and CYP4F11 in the whole patient cohort and in mismatch repair-proficient tumours.

Serum polyunsaturated fatty acid metabolites as useful tool for screening potential biomarker of colorectal cancer

The biomarker identification of cancer is benefit for early detection and less invasion. Polyunsaturated fatty acid (PUFA) metabolite as inflammatory mediators can affect progression and treatment of cancer. In this work, the serum was collected from colorectal cancer patients and healthy volunteers, and then we tested the change of serum PUFA metabolites in both of them by ultra-high performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). Of the 158 PUFA and their metabolites, we found that abnormal change of 2, 3-dinor-8-iso-PGF2α, 19-HETE and 12-keto-LTB4 from arachidonic acid were observed in colorectal cancer patients. Meanwhile, 9-HODE and 13-HODE from linoleic acid were significant lower in colorectal cancer patients. Our data suggested that some PUFA metabolites might be used as a potential biomarker of colorectal cancer, which might provide assistance in clinical diagnosis and treatment.

Nutrigenomics of extra-virgin olive oil: A review

Nutrigenomics data on the functional components of olive oil are still sparse, but rapidly increasing. Olive oil is the main source of fat and health-promoting component of the Mediterranean diet. Positive effects have been observed on genes involved in the pathobiology of most prevalent age- and lifestyle-related human conditions, such as cancer, cardiovascular disease and neurodegeneration. Other effects on health-promoting genes have been identified for bioactive components of olives and olive leafs. Omics technologies are offering unique opportunities to identify nutritional and health biomarkers associated with these gene responses, the use of which in personalized and even predictive protocols of investigation, is a main breakthrough in modern medicine and nutrition. Gene regulation properties of the functional components of olive oil, such as oleic acid, biophenols and vitamin E, point to a role for these molecules as natural homeostatic and even hormetic factors with applications as prevention agents in conditions of premature and pathologic aging. Therapeutic applications can be foreseen in conditions of chronic inflammation, and particularly in cancer, which will be discussed in detail in this review paper as major clinical target of nutritional interventions with olive oil and its functional components. © 2016 BioFactors, 43(1):17-41, 2017.

Vitamin E: Emerging aspects and new directions

The discovery of vitamin E will have its 100th anniversary in 2022, but we still have more questions than answers regarding the biological functions and the essentiality of vitamin E for human health. Discovered as a factor essential for rat fertility and soon after characterized for its properties of fat-soluble antioxidant, vitamin E was identified to have signaling and gene regulation effects in the 1980s. In the same years the cytochrome P-450 dependent metabolism of vitamin E was characterized and a first series of studies on short-chain carboxyethyl metabolites in the 1990s paved the way to the hypothesis of a biological role for this metabolism alternative to vitamin E catabolism. In the last decade other physiological metabolites of vitamin E have been identified, such as α-tocopheryl phosphate and the long-chain metabolites formed by the ω-hydroxylase activity of cytochrome P-450. Recent findings are consistent with gene regulation and homeostatic roles of these metabolites in different experimental models, such as inflammatory, neuronal and hepatic cells, and in vivo in animal models of acute inflammation. Molecular mechanisms underlying these responses are under investigation in several laboratories and side-glances to research on other fat soluble vitamins may help to move faster in this direction. Other emerging aspects presented in this review paper include novel insights on the mechanisms of reduction of the cardiovascular risk, immunomodulation and antiallergic effects, neuroprotection properties in models of glutamate excitotoxicity and spino-cerebellar damage, hepatoprotection and prevention of liver toxicity by different causes and even therapeutic applications in non-alcoholic steatohepatitis. We here discuss these topics with the aim of stimulating the interest of the scientific community and further research activities that may help to celebrate this anniversary of vitamin E with an in-depth knowledge of its action as vitamin.

The role of 20-HETE in cardiovascular diseases and its risk factors

Arachidonic acid (AA) is metabolized in mammals by enzymes of the CYP4A and 4F families to 20-hydroxyeicosatetraeonic acid (20-HETE) which plays an important role in the regulation of renal function, vascular tone and arterial pressure. In the vasculature, 20-HETE is a potent vasoconstrictor, the up-regulation of which contributes to inflammation, oxidative stress, endothelial dysfunction and an increase in peripheral vascular resistance in models of obesity, diabetes, ischemia/reperfusion, and vascular oxidative stress. Recent studies have established a role for 20-HETE in normal and pathological angiogenic conditions. We discuss in this review the synthesis of 20-HETE and how it and various autacoids, especially the renin-angiotensin system, interact to promote hypertension, vasoconstriction, and vascular dysfunction. In addition, we examine the molecular mechanisms through which 20-HETE induces these actions and the clinical implication of inhibiting 20-HETE production and activity.

Hepatic Cytochrome P450 Activity, Abundance, and Expression Throughout Human Development

Cytochrome P450s are oxidative metabolic enzymes that play critical roles in the biotransformation of endogenous compounds and xenobiotics. The expression and activity of P450 enzymes varies considerably throughout human development; the deficit in our understanding of these dynamics limits our ability to predict environmental and pharmaceutical exposure effects. In an effort to develop a more comprehensive understanding of the ontogeny of P450 enzymes, we employed a multi-omic characterization of P450 transcript expression, protein abundance, and functional activity. Modified mechanism-based inhibitors of P450s were used as chemical probes for isolating active P450 proteoforms in human hepatic microsomes with developmental stages ranging from early gestation to late adult. High-resolution liquid chromatography-mass spectrometry was used to identify and quantify probe-labeled P450s, allowing for a functional profile of P450 ontogeny. Total protein abundance profiles and P450 rRNA was also measured, and our results reveal life-stage-dependent variability in P450 expression, abundance, and activity throughout human development and frequent discordant relationships between expression and activity. We have significantly expanded the knowledge of P450 ontogeny, particularly at the level of individual P450 activity. We anticipate that these results will be useful for enabling predictive therapeutic dosing, and for avoiding potentially adverse and harmful reactions during maturation from both therapeutic drugs and environmental xenobiotics.

Cytochrome P450 and matrix metalloproteinase genetic modifiers of disease severity in Cerebral Cavernous Malformation type 1

BACKGROUND

Familial Cerebral Cavernous Malformation type 1 (CCM1) is an autosomal dominant disease caused by mutations in the Krev Interaction Trapped 1 (KRIT1/CCM1) gene, and characterized by multiple brain lesions. CCM lesions manifest across a range of different phenotypes, including wide differences in lesion number, size and susceptibility to intracerebral hemorrhage (ICH). Oxidative stress plays an important role in cerebrovascular disease pathogenesis, raising the possibility that inter-individual variability in genes related to oxidative stress may contribute to the phenotypic differences observed in CCM1 disease. Here, we investigated whether candidate oxidative stress-related cytochrome P450 (CYP) and matrix metalloproteinase (MMP) genetic markers grouped by superfamilies, families or genes, or analyzed individually influence the severity of CCM1 disease.

METHODS

Clinical assessment and cerebral susceptibility-weighted magnetic resonance imaging (SWI) were performed to determine total and large (≥5mm in diameter) lesion counts as well as ICH in 188 Hispanic CCM1 patients harboring the founder KRIT1/CCM1 'common Hispanic mutation' (CCM1-CHM). Samples were genotyped on the Affymetrix Axiom Genome-Wide LAT1 Human Array. We analyzed 1,122 genetic markers (both single nucleotide polymorphisms (SNPs) and insertion/deletions) grouped by CYP and MMP superfamily, family or gene for association with total or large lesion count and ICH adjusted for age at enrollment and gender. Genetic markers bearing the associations were then analyzed individually.

RESULTS

The CYP superfamily showed a trend toward association with total lesion count (P=0.057) and large lesion count (P=0.088) in contrast to the MMP superfamily. The CYP4 and CYP8 families were associated with either large lesion count or total lesion count (P=0.014), and two other families (CYP46 and the MMP Stromelysins) were associated with ICH (P=0.011 and 0.007, respectively). CYP4F12 rs11085971, CYP8A1 rs5628, CYP46A1 rs10151332, and MMP3 rs117153070 single SNPs, mainly bearing the above-mentioned associations, were also individually associated with CCM1 disease severity.

CONCLUSIONS

Overall, our candidate oxidative stress-related genetic markers set approach outlined CYP and MMP families and identified suggestive SNPs that may impact the severity of CCM1 disease, including the development of numerous and large CCM lesions and ICH. These novel genetic risk factors of prognostic value could serve as early objective predictors of disease outcome and might ultimately provide better options for disease prevention and treatment.

Inducible CYP4F12 enhances Hepatitis C virus infection via association with viral nonstructural protein 5B

Hepatitis C virus (HCV) nonstructural protein 5B (NS5B) functions as an RNA-dependent RNA polymerase in the HCV replication complex derived from the endoplasmic reticulum in hepatic cells. In this study, NS5B was used as bait in a yeast two-hybrid assay to screen a human liver cDNA library. We confirmed that CYP4F12, a member of the cytochrome P450 superfamily, interacted with NS5B. Furthermore, overexpression of CYP4F12 facilitated HCV replication. In contrast, knockdown of CYP4F12 by specific shRNA decreased HCV replication and viral protein expression. Moreover, our results demonstrated that HCV infection increased the binding of the transcription factor SREBP1 to the CYP4F12 promoter and activated the promoter activity, which indicated that HCV infection increased the expression of CYP4F12 through the SREBP1 pathway. Our results showed that HCV infection induced expression of CYP4F12 protein, which bound to the HCV replication complex to facilitate viral replication.

Human serum determination and in vitro anti-inflammatory activity of the vitamin E metabolite α-(13'-hydroxy)-6-hydroxychroman

Cytochrome P450-derived long-chain metabolites are gaining increasing interest as bioactive intermediates of vitamin E. In this study we first report on the HPLC-ECD and GC-MS analysis in human serum of the earliest metabolite of this vitamin, namely α-(13'-hydroxy)-6-hydroxychroman (α-13'-OH). The two chromatographic procedure are sensitive enough (LOQ of 10nM) to measure α-13'-OH after hexane extraction of 1 ml of sample obtained from healthy volunteers supplemented for 1-week with 1000 IU/d (671 mg/d) RRR-α-tocopherol. The observed concentrations ranged between 15 and 50 nM, with minor differences between fasting and 4-hr post-meal state. Baseline (non-supplemented state) levels of 7.2 ± 1.6 nM were observed extracting higher volumes of serum. Biological effects of α-13'-OH investigated for the first time in RAW264.7 murine macrophages involved transcriptional control of inflammatory cytokines, and transcriptional and functional regulation of COX2 and iNOS enzymes in response to lipopolysaccharides. In conclusion, here we present the first quantitative evaluation of serum α-13'-OH also providing early evidence of the anti-inflammatory potential of this metabolite that is worth of further investigation in the area of functional and nutraceutical implications of vitamin E metabolism.

CYP4F18-Deficient Neutrophils Exhibit Increased Chemotaxis to Complement Component C5a

CYP4Fs were first identified as enzymes that catalyze hydroxylation of leukotriene B4 (LTB4). CYP4F18 has an unusual expression in neutrophils and was predicted to play a role in regulating LTB4-dependent inflammation. We compared chemotaxis of wild-type and Cyp4f18 knockout neutrophils using an in vitro assay. There was no significant difference in the chemotactic response to LTB4, but the response to complement component C5a increased 1.9-2.25-fold in knockout cells compared to wild-type (P < 0.01). This increase was still observed when neutrophils were treated with inhibitors of eicosanoid synthesis. There were no changes in expression of other CYP4 enzymes in knockout neutrophils that might compensate for loss of CYP4F18 or lead to differences in activity. A mouse model of dextran sodium sulfate colitis was used to investigate the consequences of increased C5a-dependent chemotaxis in vivo, but there was no significant difference in weight loss, disease activity, or colonic tissue myeloperoxidase between wild-type and Cyp4f18 knockout mice. This study demonstrates the limitations of inferring CYP4F function based on an ability to use LTB4 as a substrate, points to expanding roles for CYP4F enzymes in immune regulation, and underscores the in vivo challenges of CYP knockout studies.

Cytochrome P450 ω-Hydroxylases in Inflammation and Cancer

Cytochrome P450-dependent ω-hydroxylation is a prototypic metabolic reaction of CYP4 family members that is important for the elimination and bioactivation of not only therapeutic drugs, but also endogenous compounds, principally fatty acids. Eicosanoids, derived from arachidonic acid, are key substrates in the latter category. Human CYP4 enzymes, mainly CYP4A11, CYP4F2, and CYP4F3B, hydroxylate arachidonic acid at the omega position to form 20-HETE, which has important effects in tumor progression and on angiogenesis and blood pressure regulation in the vasculature and kidney. CYP4F3A in myeloid tissue catalyzes the ω-hydroxylation of leukotriene B4 to 20-hydroxy leukotriene B4, an inactivation process that is critical for the regulation of the inflammatory response. Here, we review the enzymology, tissue distribution, and substrate selectivity of human CYP4 ω-hydroxylases and their roles as catalysts for the formation and termination of the biological effects of key eicosanoid metabolites in inflammation and cancer progression.

Transcriptome-based identification of new anti-inflammatory and vasodilating properties of the n-3 fatty acid docosahexaenoic acid in vascular endothelial cell under proinflammatory conditions [corrected]

Scope

High intakes of n-3 fatty acids exert anti-inflammatory effects and cardiovascular protection, but the underlying molecular basis is incompletely defined. By genome-wide analysis we searched for novel effects of docosahexaenoic acid (DHA) on gene expression and pathways in human vascular endothelium under pro-inflammatory conditions.

Methods and Results

Human umbilical vein endothelial cells were treated with DHA and then stimulated with interleukin(IL)-1β. Total RNA was extracted, and gene expression examined by DNA microarray. DHA alone altered the expression of 188 genes, decreasing 92 and increasing 96. IL-1β changed the expression of 2031 genes, decreasing 997 and increasing 1034. Treatment with DHA before stimulation significantly affected the expression of 116 IL-1β-deregulated genes, counter-regulating the expression of 55 genes among those decreased and of 61 among those increased. Functional and network analyses identified immunological, inflammatory and metabolic pathways as the most affected. Newly identified DHA-regulated genes are involved in stemness, cellular growth, cardiovascular system function and cancer, and included cytochrome p450 4F2(CYP4F2), transforming growth factor(TGF)-β2, Cluster of Differentiation (CD)47, caspase recruitment domain(CARD)11 and phosphodiesterase(PDE)5α.

Conclusions

Endothelial exposure to DHA regulates novel genes and related pathways. Such unbiased identification should increase our understanding of mechanisms by which n-3 fatty acids affect human diseases.

[Electrochemical methods for biomedical investigations]

In the review, authors discussed recently published experimental data concerning highly sensitive electrochemical methods and technologies for biomedical investigations in the postgenomic era. Developments in electrochemical biosensors systems for the analysis of various bio objects are also considered: cytochrome P450s, cardiac markers, bacterial cells, the analysis of proteins based on electro oxidized amino acids as a tool for analysis of conformational events. The electroanalysis of catalytic activity of cytochromes P450 allowed developing system for screening of potential substrates, inhibitors or modulators of catalytic functions of this class of hemoproteins. The highly sensitive quartz crystal microbalance (QCM) immunosensor has been developed for analysis of bio affinity interactions of antibodies with troponin I in plasma. The QCM technique allowed real-time monitoring of the kinetic differences in specific interactions and nonspecific sorption, with out multiple labeling procedures and separation steps. The affinity binding process was characterized by the association (ka) and the dissociation (kd) kinetic constants and the equilibrium association (K) constant, calculated using experimental data. Based on the electroactivity of bacterial cells, the electrochemical system for determination of sensitivity of the microbial cells to antibiotics cefepime, ampicillin, amikacin, and erythromycin was proposed. It was shown that the minimally detectable cell number corresponds to 106 CFU per electrode. The electrochemical method allows estimating the degree of E.coli JM109 cells resistance to antibiotics within 2-5 h. Electrosynthesis of polymeric analogs of antibodies for myoglobin (molecularly imprinted polymer, MIP) on the surface of graphite screen-printed electrodes as sensor elements with o- phenylenediamine as the functional monomer was developed. Molecularly imprinted polymers demonstrate selective complementary binding of a template protein molecule (myoglobin) by the "key-lock" principle.

Ethnic Differences in the Metabolism of Toluene: Comparisons between Korean and Foreign Workers Exposed to Toluene

The objectives of this study were to investigate the individual characteristics, lifestyle habits, exposure levels, and genetic diversity of xenobiotic-metabolizing enzymes involved in toluene metabolism in Korean and foreign workers exposed to toluene at a manufacturing plant. This study was conducted to determine the effects of culture or ethnicity on toluene metabolism. The results showed that blood and urinary toluene concentrations were dependent on the level of exposure to toluene. We analyzed the correlation between toluene metabolism and genetic diversity in glutathione S-transferase (GST) (M1), GSTT1, and cytochrome p-450 (CYP) 2E1*5 as well as lifestyle habits (smoking, drinking, and exercise habits). The results revealed significant correlations between toluene metabolism and GSTM1 and GSTT1 genetic diversity, as well as smoking and exercise.