A Disposable Microfluidic Device with a Screen Printed Electrode for Mimicking Phase II Metabolism

Human metabolism is investigated using several in vitro methods. However, the current methodologies are often expensive, tedious and complicated. Over the last decade, the combination of electrochemistry (EC) with mass spectrometry (MS) has a simpler and a cheaper alternative to mimic the human metabolism. This paper describes the development of a disposable microfluidic device with a screen-printed electrode (SPE) for monitoring phase II GSH reactions. The proposed chip has the potential to be used as a primary screening tool, thus complementing the current in vitro methods

Singlet oxygen production and in vitro phototoxicity studies on fenofibrate, mycophenolate mofetil, trifusal, and their active metabolites

"This is the peer reviewed version of the following article: Molins-Molina, Oscar, Roger Bresolí-Obach, Guillermo Garcia-Lainez, Inmaculada Andreu, Santi Nonell, Miguel A. Miranda, and M. Consuelo Jiménez. 2017. Singlet Oxygen Production and in Vitro Phototoxicity Studies on Fenofibrate, Mycophenolate Mofetil, Trifusal, and Their Active Metabolites. Journal of Physical Organic Chemistry 30 (9). Wiley: e3722. doi:10.1002/poc.3722, which has been published in final form at https://doi.org/10.1002/poc.3722. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving."[EN] Singlet oxygen photosensitization (studied by time-resolved near-infrared emission spectroscopy) and in vitro phototoxicity (by means of the 3T3 neutral red uptake assay) have been investigated for the prodrugs fenofibrate (FFB), mycophenolate mofetil (MMP), and trifusal (TFS) as well as for their active metabolites fenofibric acid (FFA), mycophenolic acid (MPA), and 2-hydroxy-4-(trifluoromethyl) benzoic acid (HTB). The results show that FFB and its active metabolite FFA generate O-1(2) with a quantum yield in the range 0.30 to 0.40 and show a photo-irritation factor (PIF) higher than 40. By contrast, MMP/MPA and TFS/HTB are not photoactive in the used assays. These results correlate well with the previously reported in vivo phototoxicity in treated patients.This work has been supported by grants CTQ-2013-47872C2-1-P, CTQ2016-78875-P, CTQ2013-48767-C3-1-R, CTQ2016-78454-C2-1-R, CTQ2015-71896-REDT, FIS PI16/01877, and BES-2014-069404 ( predoctoral fellowship to O. M.- M.) from MINECO. R. B.- O. thanks the European Social Funds and the SUR del DEC de la Generalitat de Catalunya for a predoctoral fellowship (2017 FI_B2 00140).Molins-Molina, O.; Bresolí-Obach, R.; García-Laínez, G.; Andreu Ros, MI.; Nonell, S.; Miranda Alonso, MÁ.; Jiménez Molero, MC. (2017). Singlet oxygen production and in vitro phototoxicity studies on fenofibrate, mycophenolate mofetil, trifusal, and their active metabolites. Journal of Physical Organic Chemistry. 30(9):1-7. https://doi.org/10.1002/poc.3722S17309Nassar, A. F. (Ed.). (2010). Biotransformation and Metabolite Elucidation of Xenobiotics. doi:10.1002/9780470890387Iyanagi, T. (2007). Molecular Mechanism of Phase I and Phase II Drug‐Metabolizing Enzymes: Implications for Detoxification. International Review of Cytology, 35-112. doi:10.1016/s0074-7696(06)60002-8Testa, B., Pedretti, A., & Vistoli, G. (2012). Reactions and enzymes in the metabolism of drugs and other xenobiotics. Drug Discovery Today, 17(11-12), 549-560. doi:10.1016/j.drudis.2012.01.017Foote, C. S. (1991). DEFINITION OF TYPE I and TYPE II PHOTOSENSITIZED OXIDATION. Photochemistry and Photobiology, 54(5), 659-659. doi:10.1111/j.1751-1097.1991.tb02071.xPalumbo, F., Garcia-Lainez, G., Limones-Herrero, D., Coloma, M. D., Escobar, J., Jiménez, M. C., … Andreu, I. (2016). Enhanced photo(geno)toxicity of demethylated chlorpromazine metabolites. Toxicology and Applied Pharmacology, 313, 131-137. doi:10.1016/j.taap.2016.10.024Ljunggren, B., & Möller, H. (1977). Phenothiazine Phototoxicity: an Experimental Study on Chlorpromazine and its Metabolites. Journal of Investigative Dermatology, 68(5), 313-317. doi:10.1111/1523-1747.ep12494582Filippatos, T., & Milionis, H. J. (2008). Treatment of hyperlipidaemia with fenofibrate and related fibrates. Expert Opinion on Investigational Drugs, 17(10), 1599-1614. doi:10.1517/13543784.17.10.1599Mele, T. S., & Halloran, P. F. (2000). The use of mycophenolate mofetil in transplant recipients. Immunopharmacology, 47(2-3), 215-245. doi:10.1016/s0162-3109(00)00190-9Plaza, L., López-Bescós, L., Martín-Jadraque, L. M., Alegrla, E., Cruz-Fernández, J. M., Velasco, J., … Zurita, A. F. (1993). Protective Effect of Triflusal against Acute Myocardial Infarction in Patients with Unstable Angina: Results of a Spanish Multicenter Trial. Cardiology, 82(6), 388-398. doi:10.1159/000175892De La Cruz, J. P., Mata, J. M., & De La Cuesta, F. S. (1992). Triflusal vs aspirin on the inhibition of human platelet and vascular cyclooxygenase. General Pharmacology: The Vascular System, 23(2), 297-300. doi:10.1016/0306-3623(92)90027-hVan Gelder, T., & Hesselink, D. A. (2015). Mycophenolate revisited. Transplant International, 28(5), 508-515. doi:10.1111/tri.12554Kuypers, D. R. J., Meur, Y. L., Cantarovich, M., Tredger, M. J., Tett, S. E., Cattaneo, D., … Gelder, T. van. (2010). Consensus Report on Therapeutic Drug Monitoring of Mycophenolic Acid in Solid Organ Transplantation. Clinical Journal of the American Society of Nephrology, 5(2), 341-358. doi:10.2215/cjn.07111009Ramis, J., Mis, R., Forn, J., Torrent, J., Gorina, E., & Jané, F. (1991). Pharmacokinetics of triflusal and its main metabolite HTB in healthy subjects following a single oral dose. European Journal of Drug Metabolism and Pharmacokinetics, 16(4), 269-273. doi:10.1007/bf03189971Darmanyan, A. P., & Foote, C. S. (1993). Solvent effects on singlet oxygen yield from n,.pi.* and .pi.,.pi.* triplet carbonyl compounds. The Journal of Physical Chemistry, 97(19), 5032-5035. doi:10.1021/j100121a029Wilkinson, F., Helman, W. P., & Ross, A. B. (1995). Rate Constants for the Decay and Reactions of the Lowest Electronically Excited Singlet State of Molecular Oxygen in Solution. An Expanded and Revised Compilation. Journal of Physical and Chemical Reference Data, 24(2), 663-677. doi:10.1063/1.555965Thomas, M. J., & Foote, C. S. (1978). CHEMISTRY OF SINGLET OXYGEN—XXVI. PHOTOOXYGENATION OF PHENOLSy. Photochemistry and Photobiology, 27(6), 683-693. doi:10.1111/j.1751-1097.1978.tb07665.xAfshari, E., & Schmidt, R. (1991). Isotope-dependent quenching of singlet molecular oxygen (1Δg) by ground-state oxygen in several perhalogenated solvents. Chemical Physics Letters, 184(1-3), 128-132. doi:10.1016/0009-2614(91)87176-cBoscá, F., & Miranda, M. A. (1999). A Laser Flash Photolysis Study on Fenofibric Acid. Photochemistry and Photobiology, 70(6), 853-857. doi:10.1111/j.1751-1097.1999.tb08293.xOECD 2004 In vitro thSerrano, G., Fortea, J. M., Latasa, J. M., Millan, F., Janes, C., Bosca, F., & Miranda, M. A. (1992). Photosensitivity induced by fibric acid derivatives and its relation to photocontact dermatitis to ketoprofen. Journal of the American Academy of Dermatology, 27(2), 204-208. doi:10.1016/0190-9622(92)70171-bCosa, G., Purohit, S., Scaiano, J. C., Boscá, F., & Miranda, M. A. (2002). A Laser Flash Photolysis Study of Fenofibric Acid in Aqueous Buffered Media: Unexpected Triplet State Inversion in a Derivative of 4-Alkoxybenzophenone¶. Photochemistry and Photobiology, 75(3), 193. doi:10.1562/0031-8655(2002)0752.0.co;2Vayá, I., Andreu, I., Monje, V. T., Jiménez, M. C., & Miranda, M. A. (2015). Mechanistic Studies on the Photoallergy Mediated by Fenofibric Acid: Photoreactivity with Serum Albumins. Chemical Research in Toxicology, 29(1), 40-46. doi:10.1021/acs.chemrestox.5b00357Miranda, M. A., Boscaa, F., Vargas, F., & Canudas, N. (1994). PHOTOSENSITIZATION BY FENOFIBRATE. II. In vitro PHOTOTOXICITY OF THE MAJOR METABOLITES. Photochemistry and Photobiology, 59(2), 171-174. doi:10.1111/j.1751-1097.1994.tb05018.xMontanaro, S., Lhiaubet-Vallet, V., Jiménez, M. C., Blanca, M., & Miranda, M. A. (2009). Photonucleophilic Addition of the ε-Amino Group of Lysine to a Triflusal Metabolite as a Mechanistic Key to Photoallergy Mediated by the Parent Drug. ChemMedChem, 4(7), 1196-1202. doi:10.1002/cmdc.200900066Nuin, E., Pérez-Sala, D., Lhiaubet-Vallet, V., Andreu, I., & Miranda, M. A. (2016). Photosensitivity to Triflusal: Formation of a Photoadduct with Ubiquitin Demonstrated by Photophysical and Proteomic Techniques. Frontiers in Pharmacology, 7. doi:10.3389/fphar.2016.00277Jiménez-Banzo, A., Ragàs, X., Kapusta, P., & Nonell, S. (2008). Time-resolved methods in biophysics. 7. Photon counting vs. analog time-resolved singlet oxygen phosphorescence detection. Photochemical & Photobiological Sciences, 7(9), 1003. doi:10.1039/b804333gOliveros, E., Suardi-Murasecco, P., Aminian-Saghafi, T., Braun, A. M., & Hansen, H.-J. (1991). 1H-Phenalen-1-one: Photophysical Properties and Singlet-Oxygen Production. Helvetica Chimica Acta, 74(1), 79-90. doi:10.1002/hlca.19910740110Schmidt, R., Tanielian, C., Dunsbach, R., & Wolff, C. (1994). Phenalenone, a universal reference compound for the determination of quantum yields of singlet oxygen O2(1Δg) sensitization. Journal of Photochemistry and Photobiology A: Chemistry, 79(1-2), 11-17. doi:10.1016/1010-6030(93)03746-4Martí, C., Jürgens, O., Cuenca, O., Casals, M., & Nonell, S. (1996). Aromatic ketones as standards for singlet molecular oxygen photosensitization. Time-resolved photoacoustic and near-IR emission studies. Journal of Photochemistry and Photobiology A: Chemistry, 97(1-2), 11-18. doi:10.1016/1010-6030(96)04321-

Isolation of the monooxygenase complex from Rhipicephalus (Boophilus) microplus:Clues to understanding acaricide resistance

The monooxygenase complex is composed of three key proteins, a cytochrome P450 (CYP), the cytochrome P450 oxidoreductase (CPR) and cytochrome b5 and plays a key role in the metabolism and detoxification of xenobiotic substances, including pesticides. In addition, overexpression of these components has been linked to pesticide resistance in several important vectors of disease. Despite this, the monooxygenase complex has not been isolated from the Southern cattle tick Rhipicephalus (Boophilus) microplus, a major disease vector in livestock. Using bioinformatics 115 transcriptomic sequences were analyzed to identify putative pesticide metabolizing CYPs. RACE-PCR was used to amplify the full length sequence of one CYP; CYP3006G8 which displays a high degree of homology to members of the CYP6 and 9 subfamilies, known to metabolize pyrethroids. mRNA expression levels of CYP3006G8 were investigated in 11 strains of R. microplus with differing resistance profiles by qPCR, the results of which indicated a correlation with pyrethroid metabolic resistance. In addition to this gene, the sequences for CPR and cytochrome b5 were also identified and subsequently isolated from R. microplus using PCR. CYP3006G8 is only the third CYP gene isolated from R. microplus and the first to putatively metabolize pesticides. The initial results of expression analysis suggest that CYP3006G8 metabolizes pyrethroids but further biochemical characterization is required to confirm this. Differences in the kinetic parameters of human and mosquito CPR in terms of NADPH binding have been demonstrated and could potentially be used to design species specific pesticides. Similar differences in the tick CPR would confirm that this is a characteristic of heamatophagous arthropods

Targeting the substrate preference of a type I nitroreductase to develop antitrypanosomal quinone-based prodrugs.

Nitroheterocyclic prodrugs are used to treat infections caused by Trypanosoma cruzi and Trypanosoma brucei. A key component in selectivity involves a specific activation step mediated by a protein homologous with type I nitroreductases, enzymes found predominantly in prokaryotes. Using data from determinations based on flavin cofactor, oxygen-insensitive activity, substrate range, and inhibition profiles, we demonstrate that NTRs from T. cruzi and T. brucei display many characteristics of their bacterial counterparts. Intriguingly, both enzymes preferentially use NADH and quinones as the electron donor and acceptor, respectively, suggesting that they may function as NADH:ubiquinone oxidoreductases in the parasite mitochondrion. We exploited this preference to determine the trypanocidal activity of a library of aziridinyl benzoquinones against bloodstream-form T. brucei. Biochemical screens using recombinant NTR demonstrated that several quinones were effective substrates for the parasite enzyme, having K(cat)/K(m) values 2 orders of magnitude greater than those of nifurtimox and benznidazole. In tests against T. brucei, antiparasitic activity mirrored the biochemical data, with the most potent compounds generally being preferred enzyme substrates. Trypanocidal activity was shown to be NTR dependent, as parasites with elevated levels of this enzyme were hypersensitive to the aziridinyl agent. By unraveling the biochemical characteristics exhibited by the trypanosomal NTRs, we have shown that quinone-based compounds represent a class of trypanocidal compound

Highly purified detergent-solubilized NADPH-cytochrome P-450 reductase from phenobarbital-induced rat liver microsomes

NADPH-cytochrome P-450 reductase was highly purified from liver microsomes of phenobarbital-induced rats by column chromatography on DEAE-cellulose, DEAE-Sephadex A-50, and hydroxylapatite in the presence of deoxycholate or Renex 690, a nonionic detergent. The purified enzyme gave a single major band with a molecular weight of 79,000 daltons on SDS-polyacrylamide gel electrophoresis. FMN and FAD were present in about equal amounts. The most active reductase preparation catalyzed the reduction of 40.9 [mu]moles of cytochrome per min per mg of protein and, as an indirect measure of cytochrome P-450 reduction, the oxidation of 2.0 [mu]moles of NADPH per min per mg of protein in a reconstituted hydroxylation system containing benzphetamine as the substrate.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/22251/1/0000687.pd

Modulation of Mrp1 (ABCc1) and Pgp (ABCb1) by Bilirubin at the Blood-CSF and Blood-Brain Barriers in the Gunn Rat

Accumulation of unconjugated bilirubin (UCB) in the brain causes bilirubin encephalopathy. Pgp (ABCb1) and Mrp1 (ABCc1), highly expressed in the blood-brain barrier (BBB) and blood-cerebrospinal fluid barrier (BCSFB) respectively, may modulate the accumulation of UCB in brain. We examined the effect of prolonged exposure to elevated concentrations of UCB on expression of the two transporters in homozygous, jaundiced (jj) Gunn rats compared to heterozygous, not jaundiced (Jj) littermates at different developmental stages (2, 9, 17 and 60 days after birth). BBB Pgp protein expression was low in both jj and Jj pups at 9 days (about 16–27% of adult values), despite the up-regulation in jj animals (2 and 1.3 fold higher than age matched Jj animals at P9 and P17–P60, respectively); Mrp1 protein expression was barely detectable. Conversely, at the BCSFB Mrp1 protein expression was rather high (60–70% of the adult values) in both jj and Jj at P2, but was markedly (50%) down-regulated in jj pups starting at P9, particularly in the 4th ventricle choroid plexuses: Pgp was almost undetectable. The Mrp1 protein down regulation was accompanied by a modest up-regulation of mRNA, suggesting a translational rather than a transcriptional inhibition. In vitro exposure of choroid plexus epithelial cells obtained from normal rats to UCB, also resulted in a down-regulation of Mrp1 protein. These data suggest that down-regulation of Mrp1 protein at the BSCFB, resulting from a direct effect of UCB on epithelial cells, may impact the Mrp1-mediated neuroprotective functions of the blood-cerebrospinal fluid barrier and actually potentiate UCB neurotoxicity

Differentiation-associated urothelial cytochrome P450 oxidoreductase predicates the xenobiotic-metabolising activity of “luminal” muscle-invasive bladder cancers

Extra-hepatic metabolism of xenobiotics by epithelial tissues has evolved as a self-defence mechanism but has potential to contribute to the local activation of carcinogens. Bladder epithelium (urothelium) is bathed in excreted urinary toxicants and pro-carcinogens. This study reveals how differentiation affects cytochrome P450 (CYP) activity and the role of NADPH:P450 oxidoreductase (POR). CYP1A1 and CYP1B1 transcripts were inducible in normal human urothelial (NHU) cells maintained in both undifferentiated and functional barrier-forming differentiated states in vitro. However, ethoxyresorufin O-deethylation (EROD) activity, the generation of reactive BaP metabolites and BaP-DNA adducts, were predominantly detected in differentiated NHU cell cultures. This gain-of-function was attributable to the expression of POR, an essential electron donor for all CYPs, which was significantly upregulated as part of urothelial differentiation. Immunohistology of muscle-invasive bladder cancer (MIBC) revealed significant overall suppression of POR expression. Stratification of MIBC biopsies into luminal and basal groups, based on GATA3 and cytokeratin 5/6 labeling, showed POR over-expression by a subgroup of the differentiated luminal tumors. In bladder cancer cell lines, CYP1-activity was undetectable/low in basal PORlo T24 and SCaBER cells and higher in the luminal POR over-expressing RT4 and RT112 cells than in differentiated NHU cells, indicating that CYP-function is related to differentiation status in bladder cancers. This study establishes POR as a predictive biomarker of metabolic potential. This has implications in bladder carcinogenesis for the hepatic versus local activation of carcinogens and as a functional predictor of the potential for MIBC to respond to prodrug therapies

Accommodating a Non-Conservative Internal Mutation by WaterMediated Hydrogen-Bonding Between β-Sheet Strands: A Comparison of Human and Rat Type B (Mitochondrial) Cytochrome b5

Mammalian type B (mitochondrial) cytochromes b5 exhibit greater amino acid sequence diversity than their type A (microsomal) counterparts, as exemplified by the type B proteins from human (hCYB5B) and rat (rCYB5B). The comparison of X-ray crystal structures of hCYB5B and rCYB5B reported herein reveals a striking difference in packing involving the five-stranded β-sheet, attributable to fully buried residue 21 in strand β4. The greater bulk of Leu21 in hCYB5B in comparison to Thr21 in rCYB5B results in a substantial displacement of the first two residues in β5, and consequent loss of two of the three hydrogen bonds between β5 and β4. Hydrogen-bonding between the residues is instead mediated by two well-ordered, fully buried water molecules. In a 10 ns molecular dynamics simulation, one of the buried water molecules in the hCYB5B structure exchanged readily with solvent via intermediates having three water molecules sandwiched between β4 and β5. When the buried water molecules were removed prior to a second 10 ns simulation, β4 and β5 formed persistent hydrogen bonds identical to those in rCYB5B, but the Leu21 side chain was forced to adopt a rarely observed conformation. Despite the apparently greater ease of water access to the interior of hCYB5B than of rCYB5B suggested by these observations, the two proteins exhibit virtually identical stability, dynamic and redox properties. The results provide new insight into the factors stabilizing the cytochrome b5 fold

Identification of NAD(P)H Quinone Oxidoreductase Activity in Azoreductases from P. aeruginosa: Azoreductases and NAD(P)H Quinone Oxidoreductases Belong to the Same FMN-Dependent Superfamily of Enzymes

Water soluble quinones are a group of cytotoxic anti-bacterial compounds that are secreted by many species of plants, invertebrates, fungi and bacteria. Studies in a number of species have shown the importance of quinones in response to pathogenic bacteria of the genus Pseudomonas. Two electron reduction is an important mechanism of quinone detoxification as it generates the less toxic quinol. In most organisms this reaction is carried out by a group of flavoenzymes known as NAD(P)H quinone oxidoreductases. Azoreductases have previously been separate from this group, however using azoreductases from Pseudomonas aeruginosa we show that they can rapidly reduce quinones. Azoreductases from the same organism are also shown to have distinct substrate specificity profiles allowing them to reduce a wide range of quinones. The azoreductase family is also shown to be more extensive than originally thought, due to the large sequence divergence amongst its members. As both NAD(P)H quinone oxidoreductases and azoreductases have related reaction mechanisms it is proposed that they form an enzyme superfamily. The ubiquitous and diverse nature of azoreductases alongside their broad substrate specificity, indicates they play a wide role in cellular survival under adverse conditions