Inhibition by pesticides of the DJ-1/Park7 protein related to Parkinson disease.

Parkinson's disease is a severe neurodegenerative disease. Several environmental contaminants such as pesticides have been suspected to favor the appearance of this pathology. The protein DJ-1 (or Park7) protects against the development of Parkinson's disease.

Human Orphan Cytochrome P450 2U1 Catalyzes the ω-Hydroxylation of Leukotriene B.

Cytochrome P450 2U1 (CYP2U1) identified from the human genome remains poorly known since few data are presently available on its physiological function(s) and substrate(s) specificity. CYP2U1 mutations are associated with complicated forms of hereditary spastic paraplegia, alterations of mitochondrial architecture and bioenergetics. In order to better know the biological roles of CYP2U1, we used a bioinformatics approach.

Unstability of cinnabarinic acid, an endogenous metabolite of tryptophan, under situations mimicking physiological conditions.

The kynurenine pathway of l-tryptophan metabolism produces several compounds of high physiological importance in the central nervous system and the immune response. Among them, cinnabarinic acid (CA) which results from the condensation of two molecules of 3-hydroxy-anthranilic acid has been identified as an activator of the metabotropic glutamate receptor (mGluR4) and the aryl hydrocarbon receptor (AhR). However, very few information was available about its stability under physiological conditions.

Cytochromes P450 of : Implication in Biological Functions and Metabolism of Xenobiotics.

is an important model used for many aspects of biological research. Its genome contains 76 genes coding for cytochromes P450 (P450s), and few data about the biochemical properties of those P450s have been published so far. However, an increasing number of articles have appeared on their involvement in the metabolism of xenobiotics and endobiotics such as fatty acid derivatives and steroids.

Comparison of Various Aryl-Dithiolethiones and Aryl-Dithiolones As Hydrogen Sulfide Donors in the Presence of Rat Liver Microsomes.

It has been reported that microsomal metabolism of ADT (5-(p-methoxyphenyl)-3H-1,2-dithiole-3-thione, anetholedithiolethione, Sulfarlem) and ADO (5-(p-methoxyphenyl)-3H-1,2-dithiole-3-one, anetholedithiolone) led to formation of HS mainly derived from oxidations catalyzed by cytochrome P450-dependent monooxygenases and that ADO was a better HS donor than ADT under these conditions. This article compares the HS donor abilities of 18 dithiolethione and dithiolone analogs of ADT and ADO upon incubation with rat liver microsomes. It shows that, for all the studied compounds, maximal HS formation was obtained after incubation with microsomes and NADPH and that this formation greatly decreased in the presence of -benzylimidazole, a known inhibitor of cytochrome P450.

Mechanism of HS Formation from the Metabolism of Anetholedithiolethione and Anetholedithiolone by Rat Liver Microsomes.

The drug anetholedithiolethione (ADT) and its analogs have been extensively used as HS donors. However, the mechanism of HS formation from ADT under biologic conditions remains almost completely unknown. This article shows that only small amounts of HS are formed during incubation of ADT and of its metabolite anetholedithiolone (ADO) with rat liver cytosol or with rat liver microsomes (RLM) in the absence of NADPH, indicating that HS formation under these conditions is of hydrolytic origin only to a minor extent.

Metabolism of Anethole Dithiolethione by Rat and Human Liver Microsomes: Formation of Various Products Deriving from Its -Demethylation and -Oxidation. Involvement of Cytochromes P450 and Flavin Monooxygenases in These Pathways.

A study of the metabolism of anethole dithiolethione (ADT, 5-(p-methoxyphenyl)-3-1,2-dithiole-3-thione) by rat and human liver microsomes showed the formation of the corresponding -oxide and the -oxide of desmethyl-ADT (dmADT, 5-(p-hydroxyphenyl)-3-1,2-dithiole-3-thione), and of p-methoxy-acetophenone (pMA) and p-hydroxy-acetophenone (pHA), in addition to the previously described metabolites, dmADT, anethole dithiolone (ADO, 5-(p-methoxyphenyl)-3-1,2-dithiole-3-one) and its demethylated derivative dmADO [5-(p-hydroxyphenyl)-3-1,2-dithiole-3-one]. The microsomal metabolism of ADO under identical conditions led to dmADO and to pMA and pHA. The metabolites of ADT derive from two competing oxidative pathways: an -demethylation catalyzed by cytochromes P450 and an -oxidation mainly catalyzed by flavin-dependent monooxygenases (FMO) and, to a minor extent, by CYP enzymes.

Role of Arginine 117 in Substrate Recognition by Human Cytochrome P450 2J2.

The influence of Arginine 117 of human cytochrome P450 2J2 in the recognition of ebastine and a series of terfenadone derivatives was studied by site-directed mutagenesis. R117K, R117E, and R117L mutants were produced, and the behavior of these mutants in the hydroxylation of ebastine and terfenadone derivatives was compared to that of wild-type CYP2J2. The data clearly showed the importance of the formation of a hydrogen bond between R117 and the keto group of these substrates.

A Novel Polyaminocarboxylate Compound To Treat Murine Pulmonary Aspergillosis by Interfering with Zinc Metabolism.

can cause pulmonary aspergillosis in immunocompromised patients and is associated with a high mortality rate due to a lack of reliable treatment options. This opportunistic pathogen requires zinc in order to grow and cause disease. Novel compounds that interfere with fungal zinc metabolism may therefore be of therapeutic interest.

A new generation of ferrociphenols leads to a great diversity of reactive metabolites, and exhibits remarkable antiproliferative properties.

Organometallic compounds bearing the redox motif [ferrocenyl--phenol] have very promising antiproliferative properties which have been further improved by incorporating pertinent substituents able to engender new mechanisms. Here we show that novel ferrociphenols bearing a hydroxypropyl chain exhibit strong antiproliferative effects, in most cases much better than those of cisplatin, tamoxifen, or of previously described ferrociphenols devoid of this terminal OH. This is illustrated, in the case of one of these compounds, by its IC values of 110 nM for MDA-MB-231 triple negative breast cancer cells and of 300 nM for cisplatin-resistant A2780cisR human ovarian cancer cells, and by its GI values lower than 100 nM towards a series of melanoma and renal cancer cell lines of the NCI-60 panel.

CYP2U1 activity is altered by missense mutations in hereditary spastic paraplegia 56.

Hereditary spastic paraplegia (HSP) is an inherited disorder of the central nervous system mainly characterized by gradual spasticity and weakness of the lower limbs. SPG56 is a rare autosomal recessive early onset complicated form of HSP caused by mutations in CYP2U1. The CYP2U1 enzyme was shown to catalyze the hydroxylation of arachidonic acid.

Membrane-bound human orphan cytochrome P450 2U1: Sequence singularities, construction of a full 3D model, and substrate docking.

Background: Human cytochrome P450 2U1 (CYP2U1) is an orphan CYP that exhibits several distinctive characteristics among the 57 human CYPs with a highly conserved sequence in almost all living organisms.

Methods: We compared its protein sequence with those of the 57 human CYPs and constructed a 3D structure of a full-length CYP2U1 model bound to a POPC membrane. We also performed docking experiments of arachidonic acid (AA) and N-arachidonoylserotonin (AS) in this model.

Cytochrome P450 2U1, a very peculiar member of the human P450s family.

Cytochrome P450 2U1 (CYP2U1) exhibits several distinctive characteristics among the 57 human CYPs, such as its presence in almost all living organisms with a highly conserved sequence, its particular gene organization with only five exons, its major location in thymus and brain, and its protein sequence involving an unusually long N-terminal region containing 8 proline residues and an insert of about 20 amino acids containing 5 arginine residues after the transmembrane helix. Few substrates, including fatty acids, N-arachidonoylserotonin (AS), and some drugs, have been reported so far. However, its biological roles remain largely unknown, even though CYP2U1 mutations have been involved in some pathological situations, such as complicated forms of hereditary spastic paraplegia.

Spectral and 3D model studies of the interaction of orphan human cytochrome P450 2U1 with substrates and ligands.

Background: Cytochrome P450 2U1 (CYP2U1) has been identified from the human genome and is highly conserved in the living kingdom. It is considered as an "orphan" protein as few data are available on its physiological function(s) and spectral characteristics. Its only known substrates reported so far are unsaturated fatty acids such as arachidonic acid (AA), and, more recently, N-arachidonoylserotonin (AS) and some xenobiotics related to debrisoquine (Deb) and terfenadine.

Ferrocenyl Quinone Methide-Thiol Adducts as New Antiproliferative Agents: Synthesis, Metabolic Formation from Ferrociphenols, and Oxidative Transformation.

Ferrociphenols (FCs) and their oxidized, electrophilic quinone methide metabolites (FC-QMs) are organometallic compounds related to tamoxifen that exhibit strong antiproliferative properties. To evaluate the reactivity of FC-QMs toward cellular nucleophiles, we studied their reaction with selected thiols. A series of new compounds resulting from the addition of these nucleophiles, the FC-SR adducts, were thus synthesized and completely characterized.

Bioactivation of clopidogrel and prasugrel: factors determining the stereochemistry of the thiol metabolite double bond.

The antithrombotics of the tetrahydrothienopyridine series, clopidogrel and prasugrel, are prodrugs that must be metabolized in two steps to become pharmacologically active. The first step is the formation of a thiolactone metabolite. The second step is a further oxidation with the formation of a thiolactone sulfoxide whose hydrolytic opening leads to a sulfenic acid that is eventually reduced into the corresponding active cis thiol.

Oxidative metabolism of ferrocene analogues of tamoxifen: characterization and antiproliferative activities of the metabolites.

Ferrociphenols have been found to have high antiproliferative activity against estrogen-independent breast cancer cells. The rat and human liver microsome-mediated metabolism of three compounds of the ferrocifen (FC) family, 1,1-bis(4-hydroxyphenyl)-2-ferrocenyl-but-1-ene (FC1), 1-(4-hydroxyphenyl)-1-(phenyl)-2-ferrocenyl-but-1-ene (FC2), and 1-[4-(3-dimethylaminopropoxy)phenyl]-1-(4-hydroxyphenyl)-2-ferrocenyl-but-1-ene (FC3), was studied. Three main metabolite classes were identified: quinone methides (QMs) deriving from two-electron oxidation of FCs, cyclic indene products (CPs) deriving from acid-catalyzed cyclization of QMs, and allylic alcohols (AAs) deriving from hydroxylation of FCs.

Expression in yeast, new substrates, and construction of a first 3D model of human orphan cytochrome P450 2U1: Interpretation of substrate hydroxylation regioselectivity from docking studies.

Background: Cytochrome P450 2U1 (CYP2U1) has been identified from the human genome and is highly conserved in the living kingdom. In humans, it has been found to be predominantly expressed in the thymus and in the brain. CYP2U1 is considered as an "orphan" enzyme as few data are available on its physiological function(s) and active site topology.

Reactions of amino acids, peptides, and proteins with oxidized metabolites of tris(p-carboxyltetrathiaaryl)methyl radical EPR probes.

Oxidation of the tris(p-carboxyltetrathiaaryl)methyl (TAM) EPR radical probe, TAMa(•), by rat liver microsomes (RLM) + NADPH, or horseradish peroxidase (HRP) + H2O2, or K2IrCl6, led to an intermediate cation, TAMa(+), which was treated with glutathione (GSH), with formation of an adduct, TAMa-SG(•), resulting from the substitution of a TAMa(•) carboxylate group with the SG group. L-α-Amino acids containing a strong nucleophilic residue (NuH), such as L-cysteine or L-histidine, also reacted with TAMa(+), with formation of radical adducts TAMa-Nu(•) in which a carboxylate group of TAMa(•) was replaced with Nu. Other less nucleophilic L-α-amino acids, such as L-arginine, L-serine, L-threonine, L-tyrosine, or L-aspartate, as well as the tetrapeptide H-(Gly)4-OH, reacted with TAMa(+) via their α-NH2 group, with formation of an iminoquinone methide, IQMa, deriving from an oxidative decarboxylation and amination of TAMa(•).

Metabolic stability of superoxide adducts derived from newly developed cyclic nitrone spin traps.

Reactive oxygen species are by-products of aerobic metabolism involved in the onset and evolution of various pathological conditions. Among them, the superoxide radical is of special interest as the origin of several damaging species such as H2O2, hydroxyl radical, or peroxynitrite (ONOO(-)). Spin trapping coupled with ESR is a method of choice to characterize these species in chemical and biological systems and the metabolic stability of the spin adducts derived from reaction of superoxide and hydroxyl radicals with nitrones is the main limit to the in vivo application of the method.

Toward stable electron paramagnetic resonance oximetry probes: synthesis, characterization, and metabolic evaluation of new ester derivatives of a tris-(para-carboxyltetrathiaaryl)methyl (TAM) radical.

Tris(p-carboxyltetrathiaaryl)methyl (TAM) radicals, such as 1a ("Finland" radical), are useful EPR probes for oximetry. However, they are rapidly metabolized by liver microsomes in the presence of NADPH, with the formation of diamagnetic quinone-methide metabolites resulting from an oxidative decarboxylation of one of their carboxylate substituents. In an effort to obtain TAM derivatives potentially more metabolically stable in vivo, we have synthesized four new TAM radicals in which the carboxylate substituents of 1a have been replaced with esters groups bearing various alkyl chains designed to render them water-soluble.

[Metabolism of xenobiotics: beneficial and adverse effects].

The systems developed by living organisms for the metabolism of xenobiotics play a key role in the adaptation of living species to their chemical environment. Recent data about mammalian cytochrome P450 structures have led to a better understanding of the molecular basis for the adaptability of these enzymes to xenobiotics exhibiting highly variable structures. The action of these enzymes on xenobiotics leads to other beneficial effects such as the bioactivation of some drugs, but also to adverse effects with the formation of aggressive metabolites for the cell that are responsible for the appearance of many toxicities.

Thiolactone sulfoxides as new reactive metabolites acting as bis-electrophiles: implication in clopidogrel and prasugrel bioactivation.

The antithrombotics of the tetrahydrothienopyridine series, clopidogrel and prasugrel, are prodrugs that must be metabolized in two steps to become pharmacologically active. The first step is the formation of a thiolactone metabolite. The second step is a cytochrome P450 (P450)-dependent oxidation of this thiolactone resulting in the formation of a sulfenic acid that is eventually reduced into the corresponding active thiol.

First combined in vivo X-ray tomography and high-resolution molecular electron paramagnetic resonance (EPR) imaging of the mouse knee joint taking into account the disappearance kinetics of the EPR probe.

Although laboratory data clearly suggest a role for oxidants (dioxygen and free radicals derived from dioxygen) in the pathogenesis of many age-related and degenerative diseases (such as arthrosis and arthritis), methods to image such species in vivo are still very limited. This methodological problem limits physiopathologic studies about the role of those species in vivo, the effects of their regulation using various drugs, and the evaluation of their levels for diagnosis of degenerative diseases. In vivo electron paramagnetic resonance (EPR) imaging and spectroscopy are unique, noninvasive methods used to specifically detect and quantify paramagnetic species.

Deciphering the activation sequence of ferrociphenol anticancer drug candidates.

The complete oxidation sequence of a model for ferrociphenols, a new class of anticancer drug candidate, is reported. Cyclic voltammetry was used to monitor the formation of oxidation intermediates on different timescales, thereby allowing the electrochemical characterization of both the short-lived and stable species obtained from the successive electron-transfer and deprotonation steps. The electrochemical preparation of the ferrocenium intermediate enabled a stepwise voltammetric determination of the stable oxidation compounds obtained upon addition of a base as well as the electron stoichiometry observed for the overall oxidation process.