Role of Mitochondria in Tributyltin-Induced Interleukin-1α Production in Murine Keratinocytes

Tributyltin (TBT) salts are well known skin irritants in rodents and humans. TBT induced both the intracellular production of Interleukin-1α (IL-1α) and its release into culture medium in a murine keratinocyte cell line (HEL30). Here, we report that mitochondria are important for TBT-induced IL-1α production.Confluent cells were treated with increasing concentrations of TBT (0–2.5 μM) or dimethylsulfoxide as vehicle control. At different times thereafter (0–24 h), nuclear extracts were analyzed for nuclear factor-κB (NF-κB) binding activity by electrophoretic mobility shift assay, and the released and cell-associated IL-1α was measured by enzyme-linked immunosorbent assay. TBT induced a direct and concentration-related activation of NF-κB, which peaked at 2h and was blocked by pyrrolidinedithiocarbamate, a potent NF-κB inhibitor, and rotenone, an inhibitor of the electron entry from complex I to ubiquinone. Rotenone also induced a concentration-related inhibition of IL-1α synthesis induced by TBT, but rotenone did not completely abrogate TBT-induced IL-1α production, which suggests that other transcription factors may be involved in IL-1α production.Prolongod treatment with ethidium bromide, an inhibitor of mitochondrial DNA and RNA synthesis, was used to partially deplete cells of functional mitochondria. After 5 d of treatment, mitochondria conversion of tetrazolium bromide to formazan was reduced by 50%, and IL-1α release was decreased by 65%, whereas no induction of intracellular IL-1α was observed. This effect was not due to inhibition prot in synthesis because identical incorporation of [3H]leucine into protein in control and ethidium bromide–treated cells was identical. This impairment of mitochondrial metabolism inhibited NF-κB activation by TBT. These findings indicate that mitochondria may be the source of second messenger molecules important for TBT-induced IL-1α production

Checklists for Applicants submitting dossiers on Cosmetic Ingredients to be evaluated by the SCCS

Checklists for Applicants submitting dossiers on Cosmetic Ingredients to be evaluated by the SCCSThe SCCS adopted these Checklists on 07 March 2017Checklists for Applicants submitting dossiers on Cosmetic Ingredients to be evaluated by the SCCSThe SCCS adopted these Checklists on 07 March 201

Origin of the TTC values for compounds that are genotoxic and/or carcinogenic and an approach for their revaluation

The threshold of toxicological concern (TTC) approach is a resource-effective de minimismethod for the safety assessment of chemicals, based on distributional analysis of the results of a large number of toxicological studies. It is being increasingly used to screen and prioritise substances with low exposure for which there is little or no toxicological information. The first step in the approach is the identification of substances that may be DNA-reactive mutagens, to which the lowest TTC value is applied. This TTC value was based on analysis of the cancer potency database and involved a number of assumptions that no longer reflect the state-of-the-science and some of which were not as transparent as they could have been. Hence, review and updating of the database is proposed, using inclusion and exclusion criteria reflecting current knowledge. A strategy for the selection of appropriate substances for TTC determination, based on consideration of weight of evidence for genotoxicity and carcinogenicity is outlined. Identification of substances that are carcinogenic by a DNA-reactive mutagenicmode of action and those that clearly act by a non-genotoxic mode of action will enable the protectiveness to be determined of both the TTC for DNA-reactive mutagenicityand that applied by default to substances that may be carcinogenic but are unlikely to be DNA-reactive mutagens (i.e. for Cramer class I-III compounds). Critical to the application of the TTC approach to substances that are likely to be DNA-reactive mutagens is the reliability of the software tools used to identify such compounds. Current methods for this task are reviewed and recommendations made for their application

Preclinical Evaluation of Tolerability of a Selective, Bacteriostatic, Locally Active Vaginal Formulation

AbstractBackgroundPolybactum (Effik International, Brussels, Belgium) is a vaginal mucoadhesive product (medical device) designed to form a film that acts as a mechanical barrier with the aim of inhibiting colonization by specific pathogens. It contains polycarbophil, a bioadhesive agent, and lauryl glucoside (LG), a nonionic surfactant that reinforces the barrier effect through its tensioactive properties.ObjectiveTo assess the local safety profile, tolerability, and efficacy of Polybactum formulations.MethodsThe following studies were performed on 3 Polybactum formulations: 2 ovules (Type 1: LG 0.04% and Type 2: LG 0.1%) and 1 gel formulation. Bacteriologic tests assessing the effects on normal vaginal flora and pathogens; in vitro and in vivo tests designed to assess cytotoxicity, as well as irritant and sensitizing potentials; biocompatibility, barrier, residence time, and absorption tests using reconstituted human vaginal epithelium were performed.ResultsPolybactum is a selective bacteriostatic agent that is active against Streptococcus agalactiae and Gardnerella vaginalis while sparing normal vaginal flora; that is, Lactobacillus spp. It had no cytotoxic, irritant, and sensitizing effects nor did it impair barrier and fence functions of the vaginal epithelium. The Type 1 ovule showed film-forming properties in vitro. Finally, LG absorption through reconstituted human vaginal epithelium was negligible, ruling out the risk for possible systemic toxicity.ConclusionsThis favorable preclinical profile is encouraging and supports clinical studies on Polybactum Type 1 ovules for the prevention and management of recurring bacterial vaginosis

Preclinical Evaluation of Tolerability of a Selective, Bacteriostatic, Locally Active Vaginal Formulation

Background: Polybactum (Effik International, Brussels, Belgium) is a vaginal mucoadhesive product (medical device) designed to form a film that acts as a mechanical barrier with the aim of inhibiting colonization by specific pathogens. It contains polycarbophil, a bioadhesive agent, and lauryl glucoside (LG), a nonionic surfactant that reinforces the barrier effect through its tensioactive properties. Objective: To assess the local safety profile, tolerability, and efficacy of Polybactum formulations. Methods: The following studies were performed on 3 Polybactum formulations: 2 ovules (Type 1: LG 0.04% and Type 2: LG 0.1%) and 1 gel formulation. Bacteriologic tests assessing the effects on normal vaginal flora and pathogens; in vitro and in vivo tests designed to assess cytotoxicity, as well as irritant and sensitizing potentials; biocompatibility, barrier, residence time, and absorption tests using reconstituted human vaginal epithelium were performed. Results: Polybactum is a selective bacteriostatic agent that is active against Streptococcus agalactiae and Gardnerella vaginalis while sparing normal vaginal flora; that is, Lactobacillus spp. It had no cytotoxic, irritant, and sensitizing effects nor did it impair barrier and fence functions of the vaginal epithelium. The Type 1 ovule showed film-forming properties in vitro. Finally, LG absorption through reconstituted human vaginal epithelium was negligible, ruling out the risk for possible systemic toxicity. Conclusions: This favorable preclinical profile is encouraging and supports clinical studies on Polybactum Type 1 ovules for the prevention and management of recurring bacterial vaginosis

A Computational Approach to Evaluate the Androgenic Affinity of Iprodione, Procymidone, Vinclozolin and Their Metabolites

<div><p>Our research is aimed at devising and assessing a computational approach to evaluate the affinity of endocrine active substances (EASs) and their metabolites towards the ligand binding domain (LBD) of the androgen receptor (AR) in three distantly related species: human, rat, and zebrafish. We computed the affinity for all the selected molecules following a computational approach based on molecular modelling and docking. Three different classes of molecules with well-known endocrine activity (iprodione, procymidone, vinclozolin, and a selection of their metabolites) were evaluated. Our approach was demonstrated useful as the first step of chemical safety evaluation since ligand-target interaction is a necessary condition for exerting any biological effect. Moreover, a different sensitivity concerning AR LBD was computed for the tested species (rat being the least sensitive of the three). This evidence suggests that, in order not to over−/under-estimate the risks connected with the use of a chemical entity, further <i>in vitro</i> and/or <i>in vivo</i> tests should be carried out only after an accurate evaluation of the most suitable cellular system or animal species. The introduction of <i>in silico</i> approaches to evaluate hazard can accelerate discovery and innovation with a lower economic effort than with a fully wet strategy.</p></div

Increased carrageenan-induced acute lung inflammation in old rats

Ageing is associated with increased susceptibility to lung infections and delayed resolution of pulmonary infiltrates. The purpose of this study was to investigate the effect of age on the onset of carrageenan-induced lung inflammation. When compared with carrageenan-treated young rats (3 months old), old rats (> 18 months old) exhibited a preponderance of pleural exudation and polymorphonuclear cell infiltration. Lung myeloperoxidase activity, an index of neutrophil infiltration and activation, was significantly increased in old rats in comparison with young rats. Consistent with the biochemical markers of inflammation, increased lung damage, as assessed by nitrosative stress and lipid peroxidation, was observed in carrageenan-treated old rats. In the lung exudate obtained from old rats, a significant reduction in interleukin-10 (IL-10) was observed, while similar expression of monocyte chemotactic protein-1 was induced, suggesting that a decrease in IL-10 rather than increased chemotaxis may account for the preponderance of the inflammatory cellular infiltrate in old rats. Similar to the in vivo situation, freshly isolated alveolar macrophages obtained from old rats produced less IL-10. This defective IL-10 production could be explained by a reduction in the cAMP-dependent signalling pathway, which mediates IL-10 production. Indeed, we found decreased cAMP-responsive element binding protein (CREB) and phosphorous-CREB (P-CREB) expression in old rats, which may account for reduced IL-10 production in old rats

Increased carrageenan-induced acute lung inflammation in old rats

Ageing is associated with increased susceptibility to lung infections and delayed resolution of pulmonary infiltrates. The purpose of this study was to investigate the effect of age on the onset of carrageenan-induced lung inflammation. When compared with carrageenan-treated young rats (3 months old), old rats (> 18 months old) exhibited a preponderance of pleural exudation and polymorphonuclear cell infiltration. Lung myeloperoxidase activity, an index of neutrophil infiltration and activation, was significantly increased in old rats in comparison with young rats. Consistent with the biochemical markers of inflammation, increased lung damage, as assessed by nitrosative stress and lipid peroxidation, was observed in carrageenan-treated old rats. In the lung exudate obtained from old rats, a significant reduction in interleukin-10 (IL-10) was observed, while similar expression of monocyte chemotactic protein-1 was induced, suggesting that a decrease in IL-10 rather than increased chemotaxis may account for the preponderance of the inflammatory cellular infiltrate in old rats. Similar to the in vivo situation, freshly isolated alveolar macrophages obtained from old rats produced less IL-10. This defective IL-10 production could be explained by a reduction in the cAMP-dependent signalling pathway, which mediates IL-10 production. Indeed, we found decreased cAMP-responsive element binding protein (CREB) and phosphorous-CREB (P-CREB) expression in old rats, which may account for reduced IL-10 production in old rats

Experimental (from [27]) and <i>in silico</i> (computed) dissociation constants for the selected compounds with respect to rat AR binding site.

<p>ΔG-MD: binding free energy computed through molecular docking.</p