Verruculogen associated with Aspergillus fumigatus hyphae and conidia modifies the electrophysiological properties of human nasal epithelial cells

BACKGROUND: The role of Aspergillus fumigatus mycotoxins in the colonization of the respiratory tract by conidia has not been studied extensively, even though patients at risk from invasive aspergillosis frequently exhibit respiratory epithelium damage. In a previous study, we found that filtrates of A. fumigatus cultures can specifically alter the electrophysiological properties of human nasal epithelial cells (HNEC) compared to those of non pathogenic moulds. RESULTS: We fractionated the organic phase of filtrate from 3-day old A. fumigatus cultures using high-performance liquid chromatography. The different fractions were tested for their ability to modify the electrophysiological properties of HNEC in an in vitro primary culture model. The fraction collected between 20 and 30 min mimicked the effects of the whole filtrate, i.e. decrease of transepithelial resistance and increase of potential differences, and contained secondary metabolites such as helvolic acid, fumagillin, and verruculogen. Only verruculogen (10(-8 )M) had effects similar to the whole filtrate. We verified that verruculogen was produced by a collection of 67 human, animal, plant and environmental A. fumigatus isolates. Using MS-MS analysis, we found that verruculogen was associated with both mycelium and conidia extracts. CONCLUSION: Verruculogen is a secondary metabolite that modifies the electrophysiological properties of HNEC. The role of these modifications in the colonization and invasion of the respiratory epithelium by A. fumigatus on first contact with the epithelium remains to be determined

Verruculogen associated with Aspergillus fumigatus hyphae and conidia modifies the electrophysiological properties of human nasal epithelial cells

BACKGROUND: The role of Aspergillus fumigatus mycotoxins in the colonization of the respiratory tract by conidia has not been studied extensively, even though patients at risk from invasive aspergillosis frequently exhibit respiratory epithelium damage. In a previous study, we found that filtrates of A. fumigatus cultures can specifically alter the electrophysiological properties of human nasal epithelial cells (HNEC) compared to those of non pathogenic moulds. RESULTS: We fractionated the organic phase of filtrate from 3-day old A. fumigatus cultures using high-performance liquid chromatography. The different fractions were tested for their ability to modify the electrophysiological properties of HNEC in an in vitro primary culture model. The fraction collected between 20 and 30 min mimicked the effects of the whole filtrate, i.e. decrease of transepithelial resistance and increase of potential differences, and contained secondary metabolites such as helvolic acid, fumagillin, and verruculogen. Only verruculogen (10(-8 )M) had effects similar to the whole filtrate. We verified that verruculogen was produced by a collection of 67 human, animal, plant and environmental A. fumigatus isolates. Using MS-MS analysis, we found that verruculogen was associated with both mycelium and conidia extracts. CONCLUSION: Verruculogen is a secondary metabolite that modifies the electrophysiological properties of HNEC. The role of these modifications in the colonization and invasion of the respiratory epithelium by A. fumigatus on first contact with the epithelium remains to be determined

In Vitro Cytochrome P450 Formation of a Mono-Hydroxylated Metabolite of Zearalenone Exhibiting Estrogenic Activities: Possible Occurrence of This Metabolite in Vivo

The mycoestrogen zearalenone (ZEN), as well as its reduced metabolites, which belong to the endocrine disruptor bio-molecule family, are substrates for various enzymes involved in steroid metabolism. In addition to its reduction by the steroid dehydrogenase pathway, ZEN also interacts with hepatic detoxification enzymes, which convert it into hydroxylated metabolites (OH-ZEN). Due to their structures to that of estradiol, ZEN and its derived metabolites bind to the estrogen receptors and are involved in endocrinal perturbations and are possibly associated with estrogen-dependent cancers. The primary aim of this present study was to identify the enzymatic cytochrome P450 isoforms responsible for the formation of the most abundant OH-ZEN. We thus studied its in vitro formation using hepatic microsomes in a range of animal model systems including man. OH-ZEN was also recovered in liver and urine of rats treated orally with ZEN. Finally we compared the activity of ZEN and its active metabolites (α-ZAL and OH-ZEN) on estrogen receptors using HeLa ER-α and ER-β reporter cell lines as reporters. OH-ZEN estrogenic activities were revealed to be limited and not as significant as those of ZEN or α-ZAL

Métabolisme et pharmacocinétique de composés peptidiques et cyclopeptidiques (utilisation de radioéléments et d'isotopes stables)

Actuellement plus d'une centaine de peptides et protéines sont commercialisés ou en cours de développement. Les études de pharmacocinétique et de métabolisme de ces composés reposent sur l'utilisation de 3 techniques principales : l'utilisation de composés marqués " ponctuellement " sur un acide aminé avec des radioéléments, de détections immunologiques et depuis quelque temps de la spectrométrie de masse.La première partie de ce travail a consisté à évaluer à l'aide de peptides modèles (insuline et peptide C) l'intérêt du marquage uniforme avec des isotopes stables ( 13C, 15N et 13C/15N) ou de 14C dans ce type d'étude. Ces travaux se basent principalement sur un dosage par dilution isotopique couplé à la spectrométrie de masse.Dans un second temps, nous nous sommes intéressés à une famille de cyclopeptides composés de deux acides aminés, les dicétopipérazines. Ces produits sont retrouvés à la fois chez les mammifères et chez les microorganismes. Non reconnus par les enzymes protéolytiques des mammifères, nous avons évalué leur prise en charge, à l'aide de deux composés modèles la roquefortine et la phenylahistin, par les principales enzymes intervenant dans le métabolisme des xénobiotiques, les monooxygénases à cytochrome P450s.More and more peptides and proteins are used in therapeutic. Three mainly technics are used for pharmacokinetic and metabolism studies: immunoassay, radioactively labeled molecules and mass spectrometry.In the first part of this work, we've used uniformely labelled peptides (C-peptide and insulin) with stables (13C, 15N, and 13C/15N) or radioactive (14C) isotopes to investigated these kind of studies. These works are based on isotope dilution mass spectrometry assay.In a second time we've investigated the metabolism of a particular cyclopeptides families composed of two amino acids : the diketopiperazine. These compounds are found in mammals and in microorganisms. There are not recognized by proteolytic enzymes. We've estimated if the main enzymes implicated in the metabolism of xenobiotics, the P450 cytochrome monooxygenases, were able to recognized them.PARIS-BIUP (751062107) / SudocSudocFranceF

Implication des cytochromes P450 dans la biotransformation des composés exogènes (mise au point d'une méthode de screening haut-débit)

PARIS-BIUP (751062107) / SudocSudocFranceF

Complémentarité des protéines de détoxication et trafic intracellulaire (recherche de liens fonctionnels entre le cytochrome P450 3A et la P-glycoprotéine)

PARIS-BIUP (751062107) / SudocSudocFranceF

Effet inhibiteur de la roquefortine sur les cytochromes P450 hépatiques

TOULOUSE3-BU Santé-Centrale (315552105) / SudocSudocFranceF

Étude du métabolisme et du transport de composés exogènes grâce à l'enrichissement isotopique uniforme au 13C

CHATENAY MALABRY-Ecole centrale (920192301) / SudocSudocFranceF

Caractérisation des micro-organismes dans les taches de foxing des papiers :nouvelles approches analytiques

International audienc

Food quality monitoring and analytical techniques optimization of some aliments within plant-animal correlation (Contaminated aliments effects on the detoxification enzymes)

LE KREMLIN-B.- PARIS 11-BU Méd (940432101) / SudocSudocFranceF