The evaluation of engineered nanomaterial safety has been hindered by conflicting reports demonstrating differential degrees of toxicity with the same nanoparticles. The unique properties of these materials increase the likelihood that they will interfere with analytical techniques, which may contribute to this phenomenon. We tested the potential for: 1) nanoparticle intrinsic fluorescence/absorbance, 2) interactions between nanoparticles and assay components, and 3) the effects of adding both nanoparticles and analytes to an assay, to interfere with the accurate assessment of toxicity. Silicon, cadmium selenide, titanium dioxide, and helical rosette nanotubes each affected at least one of the six assays tested, resulting in either substantial over- or under-estimations of toxicity. Simulation of realistic assay conditions revealed that interference could not be predicted solely by interactions between nanoparticles and assay components. Moreover, the nature and degree of interference cannot be predicted solely based on our current understanding of nanomaterial behaviour. A literature survey indicated that ca. 95% of papers from 2010 using biochemical techniques to assess nanotoxicity did not account for potential interference of nanoparticles, and this number had not substantially improved in 2012. We provide guidance on avoiding and/or controlling for such interference to improve the accuracy of nanotoxicity assessments.

Eosinophil degranulation is a determining factor in allergy-mediated airway pathology. Receptor-mediated degranulation in eosinophils requires vesicle-associated membrane protein 7 (VAMP-7), a principal component of the SNARE fusion machinery. The specific contribution of eosinophil degranulation to allergen-induced airway responses remains poorly understood. We generated mice with VAMP-7 gene deficiency exclusively in eosinophils (eoCRE/V7) from a cross using eosinophil-specific Cre recombinase-expressing mice crossed with VAMP-7f/f mice. Eosinophils from eoCRE/V7 mice showed deficient degranulation responses in vitro, and responses continued to be decreased following ex vivo intratracheal adoptive transfer of eoCRE/V7 eosinophils into IL-5/hE2/EPX−/− mice. Consistent with diminished degranulation responses, reduced airway hyperresponsiveness was observed in ovalbumin-sensitized and challenged eoCRE/V7 mice following methacholine inhalation. Therefore, VAMP-7 mediates eosinophil degranulation both in vitro and ex vivo, and this event augments airway hyperresponsiveness.

Coated nanoparticles (NPs) will end up in the environment due to their proposed use in agricultural applications and may potentially cause toxic effects due to their unique properties. To determine the effects of coated NPs on zebrafish (Danio rerio) development, we tested aqueous poly(acrylic acid) (PAA)-coated metal-oxide NPs including TiO2, ZnO, Fe2O3, and CeO2, as well as the polymer coating alone (nanocapsule). Zebrafish embryos were exposed to NPs over a 72 h period at 1, 10, 50, 100, 200, 400, 800, 1200, 1600, and 2000 mg/L to measure various end points. We also ran free metal controls. Time-dependent changes in physicochemical properties of NPs were characterized using dynamic light scattering. Dissolution experiments over 72 h showed minimal free metals were present in stock suspensions and released from the NPs. Interestingly, nanocapsules (≥ 800 mg/L) cause inhibition of hatch, and we suggest that a low pH environment may explain this effect. This study has also demonstrated that CeO2 NPs and nanocapsules containing Nile red are able to traverse the chorion. Overall, our findings indicate that each NP type is stable and neither the NP or encapsulating PAA coating causes apparent toxicity to developing zebrafish.

Introduction:Eosinophils have been long implicated in antiparasite immunity and allergic diseases and, more recently, in regulating adipose tissue homeostasis. The metabolic processes that govern eosinophils, particularly upon activation, are unknown. Methods:Peripheral blood eosinophils were isolated for the analysis of metabolic processes using extracellular flux analysis and individual metabolites by stable isotope tracer analysis coupled to gas chromatography-mass spectrometry following treatment with IL-3, IL-5 or granulocyte-macrophage colony-stimulating factor (GM-CSF). Eosinophil metabolism was elucidated using pharmacological inhibitors.Results: Human eosinophils engage a largely glycolytic metabolism but also employ mitochondrial metabolism. Cytokine stimulation generates citric acid cycle (TCA) intermediates from both glucose and glutamine revealing this previously unknown role for mitochondria upon eosinophil activation. We further show that the metabolic programme driven by IL-5 is dependent on the STAT5/PI3K/Akt signalling axis and that nicotinamide adenine dinucleotide phosphate oxidase (NOX)-dependent ROS production might be a driver of mitochondrial metabolism upon eosinophil activation. Conclusion:We demonstrate for the first time that eosinophils are capable of metabolic plasticity, evidenced by increased glucose-derived lactate production upon ROS inhibition.Collectively, this study reveals a role for both glycolysis and mitochondrial metabolism in cytokine-stimulated eosinophils. Selective targeting of eosinophil metabolism may be of therapeutic benefit in eosinophil-mediated diseases and regulation of tissue homeostasis. K E Y W O R D Seosinophils, glycolysis, IL-5, metabolism, TCA cycle

We report a novel finding of ANCA-reactivity in the sputa of eGPA patients in whom disease severity is driven by respiratory complications. Investigating localized autoimmunity may lead to the discovery of novel pathomechanisms, therapeutic targets, and optimal biomarkers for diagnosing and managing eGPA.