Lucas C.D.,Queens Medical Research Institute |
Allen K.C.,Queens Medical Research Institute |
Dorward D.A.,Queens Medical Research Institute |
Hoodless L.J.,Queens Medical Research Institute |
And 7 more authors.
FASEB Journal | Year: 2013
Neutrophil apoptosis and subsequent nonphlogistic clearance by surrounding phagocytes are key to the successful resolution of neutrophilic inflammation, with dysregulated apoptosis reported in multiple human inflammatory diseases. Enhancing neutrophil apoptosis has proresolution and anti-inflammatory effects in preclinical models of inflammation. Here we investigate the ability of the flavones apigenin, luteolin, and wogonin to induce neutrophil apoptosis in vitro and resolve neutrophilic inflammation in vivo. Human neutrophil apoptosis was assessed morphologically and by flow cytometry following incubation with apigenin, luteolin, and wogonin. All three flavones induced timeand concentration-dependent neutrophil apoptosis (apigenin, EC50=12.2 μM; luteolin, EC50=14.6 μM; and wogonin, EC50=28.9 μM). Induction of apoptosis was caspase dependent, as it was blocked by the broadspectrum caspase inhibitor Q-VD-OPh and was associated with both caspase-3 and caspase-9 activation. Flavone-induced apoptosis was preceded by down-regulation of the prosurvival protein Mcl-1, with proteasomal inhibition preventing flavone-induced Mcl-1 down-regulation and apoptosis. The flavones abrogated the survival effects of mediators that prolong neutrophil life span, including lipoteichoic acid, peptidoglycan, dexamethasone, and granulocyte-macrophage colony stimulating factor, by driving apoptosis. Furthermore, wogonin enhanced resolution of established neutrophilic inflammation in a zebrafish model of sterile tissue injury. Wogonin-induced resolution was dependent on apoptosis in vivo as it was blocked by caspase inhibition. Our data show that the flavones induce neutrophil apoptosis and have potential as neutrophil apoptosis-inducing anti-inflammatory, proresolution agents. © The Author(s).
Donaldson K.,University of Edinburgh |
Schinwald A.,University of Edinburgh |
Murphy F.,Dong - A University |
Cho W.-S.,MRC Toxicology Unit |
And 3 more authors.
Accounts of Chemical Research | Year: 2013
In all branches of toxicology, the biologically effective dose (BED) is thefraction of the total dose of a toxin that actually drives any toxic effect. Knowledge of the BED has a number of applications including in building structure-activity relationships, the selection of metrics, the design of safe particles, and the determination of when a nanoparticle (NP) can be considered to be "new" for regulatory purposes. In particle toxicology, we define the BED as "the entity within any dose of particles in tissue that drives a critical pathophysiogically relevant form of toxicity (e.g., oxidative stress, inflammation, genotoxicity, or proliferation) or a process that leads to it."In conventional chemical toxicology, researchers generally use the mass as the metric to describe dose (such as mass per unit tissue or cells in culture) because of its convenience. Concentration, calculated from mass, may also figure in any description of dose. In the case of a nanoparticle dose, researchers use either the mass or the surface area. The mass of nanoparticles is not the only driver of their activity: the surfaces of insoluble particles interact with biological systems, and soluble nanoparticles can release factors that interact with these systems. Nanoparticle shape can modify activity.In this Account, we describe the current knowledge of the BED as it pertains to different NP types. Soluble toxins released by NPs represent one potential indicator of BED for wholly or partially soluble NPs composed of copper or zinc. Rapid dissolution of these NPs into their toxic ions in the acidic environment of the macrophage phagolysosome causes those ions to accumulate, which leads to lysosome destabilization and inflammation. In contrast, soluble NPs that release low toxicity ions, such as magnesium oxide NPs, are not inflammogenic. For insoluble NPs, ζ potential can serve as a BED measurement because the exposure of the particle surface to the acidic milieu of the phagolysosome and interactions with the lysosomal membrane can compromise the integrity of the NPs. Researchers have explored oxidative potential of NPs most extensively as an indicator of the BED: the ability of an NP to cause oxidative stress in cells is a key factor in determining cell toxicity, inflammogenicity, and oxidative DNA adduct formation. Finally we discuss BEDs for high aspect ratio nanoparticles because long fibers or nanoplatelets can cause inflammation and further effects. These consequences arise from the paradoxically small aerodynamic diameter of fibers or thin platelets. As a result, these NPs can deposit beyond the ciliated airways where their extended dimensions prevent them from being fully phagocytosed by macrophages, leading to frustrated phagocytosis. Although knowledge is accumulating on the BED for NPs, many questions and challenges remain in understanding and utilizing this important nanotoxicological parameter. © 2012 American Chemical Society.
Chauvigne F.,French Institute of Health and Medical Research |
Plummer S.,CXR Biosciences |
Lesne L.,French Institute of Health and Medical Research |
Cravedi J.-P.,French National Institute for Agricultural Research |
And 3 more authors.
PLoS ONE | Year: 2011
Exposure to phthalates in utero alters fetal rat testis gene expression and testosterone production, but much remains to be done to understand the mechanisms underlying the direct action of phthalate within the fetal testis. We aimed to investigate the direct mechanisms of action of mono-(2-ethylhexyl) phthalate (MEHP) on the rat fetal testis, focusing on Leydig cell steroidogenesis in particular. We used an in vitro system based on the culture for three days, with or without MEHP, of rat fetal testes obtained at 14.5 days post-coitum. Exposure to MEHP led to a dose-dependent decrease in testosterone production. Moreover, the production of 5 alpha-dihydrotestosterone (5α-DHT) (-68%) and androstenedione (-54%) was also inhibited by 10 μM MEHP, whereas 17 alpha-hydroxyprogesterone (17α-OHP) production was found to increase (+41%). Testosterone synthesis was rescued by the addition of androstenedione but not by any of the other precursors used. Thus, the hormone data suggested that steroidogenesis was blocked at the level of the 17,20 lyase activity of the P450c17 enzyme (CYP17), converting 17α-OHP to androstenedione. The subsequent gene expression and protein levels supported this hypothesis. In addition to Cyp17a1, microarray analysis showed that several other genes important for testes development were affected by MEHP. These genes included those encoding insulin-like factor 3 (INSL3), which is involved in controlling testicular descent, and Inha, which encodes the alpha subunit of inhibin B. These findings indicate that under in vitro conditions known to support normal differentiation of the fetal rat testis, the exposure to MEHP directly inhibits several important Leydig cell factors involved in testis function and that the Cyp17a1 gene is a specific target to MEHP explaining the MEHP-induced suppression of steroidogenesis observed. © 2011 Chauvigné et al.
Agency: Cordis | Branch: FP7 | Program: CP-IP | Phase: HEALTH.2010.4.2-9-1 | Award Amount: 9.40M | Year: 2011
In the development of products for use by humans it is vital to identify compounds with toxic properties at an early stage of their development, to avoid spending time and resource on unsuitable and potentially unsafe candidate products. Human pluripotent stem cell lines offer a unique opportunity to develop a wide variety of human cell-based test systems because they may be expanded indefinitely and triggered to differentiate into any cell type. SCR&Tox aims at making use of these two attributes to provide in vitro assays for predicting toxicity of pharmaceutical compounds and cosmetic ingredients. The consortium has been designed to address all issues related with biological and technological resources to meet that goal. In order to demonstrate the value of pluripotent stem cells for toxicology, the consortium will focus on four complementary aspects: Relevance i.e. establishing and maintaining discrete cell phenotypes over long-term cultures; providing large versatility to adapt to assays of specific pathways. Efficiency for i) automated cell production and differentiation, ii) cell engineering for differentiation and selection iii) multi-parametric toxicology using functional genomic, proteomic and bioelectronics. Extension i.e. i) scalability through production of cells and technologies for industrial-scale assays, and ii) diversity of phenotypes (5 different tissues), and of genotypes (over 30 different donors). Normalization validation and demonstration of reproducibility and robustness of cell-based assays on industrial-scale platforms, to allow for secondary development in the pharmaceutical and cosmetic industry. SCR&Tox will be intricately associated to other consortia of the Alternative Testing call, sharing biological, technological and methodological resources. Proof of concept of the proposed pluripotent stem cell-based assays for toxicology will be provided on the basis of toxicity pathways and test compounds identified by other consortia.
CXR Biosciences | Date: 2011-03-24
The molecules of formula (I) are useful in treating diabetes, obesity, hypercholesterolaemia, hyperlipidaemia, cancer, inflammation or other conditions in which modulation of lipis of eicosanoid status or functions may be desirable. Formula (I): Z