Induction of Innate Memory in Human Monocytes Exposed to Mixtures of Bacterial Agents and Nanoparticles

Innate memory; Macrophages; MonocytesMemoria innata; Macrófagos; MonocitosMemòria innata; Macròfags; MonòcitsWe assessed whether concomitant exposure of human monocytes to bacterial agents and different engineered nanoparticles can affect the induction of protective innate memory, an immune mechanism that affords better resistance to diverse threatening challenges. Monocytes were exposed in vitro to nanoparticles of different chemical nature, shape and size either alone or admixed with LPS, and cell activation was assessed in terms of production of inflammatory (TNFα, IL-6) and anti-inflammatory cytokines (IL-10, IL-1Ra). After return to baseline conditions, cells were re-challenged with LPS and their secondary “memory” response measured. Results show that nanoparticles alone are essentially unable to generate memory, while LPS induced a tolerance memory response (less inflammatory cytokines, equal or increased anti-inflammatory cytokines). LPS-induced tolerance was not significantly affected by the presence of nanoparticles during the memory generation phase, although with substantial donor-to-donor variability. This suggests that, despite the overall lack of significant effects on LPS-induced innate memory, nanoparticles may have donor-specific effects. Thus, future nanosafety assessment and nanotherapeutic strategies will need a personalized approach in order to ensure both the safety and efficacy of nano medical compounds for individual patients.This work was supported by the EU Commission H2020 projects PANDORA (GA671881) and ENDONANO (GA 812661) (PI, DB), the Italian MIUR InterOmics Flagship projects MEMORAT and MAME (DB, PI), and the Presidential International Fellowship Program (PIFI) of the Chinese Academy of Science (2020VBA0028) (DB). Part of this work was carried out in the context of the JRC Visiting Scientist agreement no. 05/JRC.F.2/2019 (Directorate F—Health, Consumers and Reference Materials, Consumer Products Safety, Nanobiotechnology Lab)

Certification of Reference Materials of Soya Seed Powder with different Mass Fractions of Genetically Modified 305423 Soya, Certified Reference Materials ERM-BF426 (ERM-BF426a, ERM-BF426b, ERM-BF426c, ERM-BF426d)

This report describes the processing and certification of four soya seed powder Certified Reference Materials (CRMs) containing different mass fractions of genetically modified (GM) 305423 soya (ERM-BF426a, b, c, d). The materials were processed and certified in 2007 by the European Commission, Directorate General Joint Research Centre, Institute for Reference Materials and Measurements (IRMM, Geel, Belgium), according to the principles of ISO Guide 34. The CRMs are intended to be used for quality control or calibration of methods for the quantification of the 305423 soya mass fraction in food and feed. The CRMs are available in glass bottles containing 1 g of dried soya powder closed under argon atmosphere. The minimum amount of sample to be used per analysis is 200 mg. The four CRMs have been accepted as European Reference Material (ERM) after peer evaluation by the partners of the European Reference Materials consortium.JRC.D.2-Reference material

Monitoring Anti-PEG Antibodies Level upon Repeated Lipid Nanoparticle-Based COVID-19 Vaccine Administration

PEGylated lipids are one of the four constituents of lipid nanoparticle mRNA COVID-19 vaccines. Therefore, various concerns have been raised on the generation of anti-PEG antibodies and their potential role in inducing hypersensitivity reactions following vaccination or in reducing vaccine efficacy due to anti-carrier immunity. Here, we assess the prevalence of anti-PEG antibodies, in a cohort of vaccinated individuals, and give an overview of their time evolution after repeated vaccine administrations. Results indicate that, in our cohort, the presence of PEG in the formulation did not influence the level of anti-Spike antibodies generated upon vaccination and was not related to any reported, serious adverse effects. The time-course analysis of anti-PEG IgG showed no significant booster effect after each dose, whereas for IgM a significant increase in antibody levels was detected after the first and third dose. Data suggest that the presence of PEG in the formulation does not affect safety or efficacy of lipid-nanoparticle-based COVID-19 vaccines

Physicochemical characterisation of gold, silica and silver nanoparticles in water and in serum-containing cell culture media

This report presents the results from a study organised under the coordination of JRC as part of a project aiming at the adaptation of the in vitro micronucleus test (Test Guideline 487) for the assessment of manufactured NMs. The aim of the first step of the project was to evaluate the physicochemical characterisation of selected representative nanomaterials (5 nm gold, 30 nm gold, 22 nm silica, 30 nm citrate and 30 nm PVP stabilised silver nanoparticles) in pure water and in different complete culture media. The results of the study show that using a combination of different characterisation techniques is important to providing reliable information about the agglomeration behaviour of the tested nanoparticles in complete cell culture media (CCM). Most of the materials exhibited mild agglomeration in serum containing CCM. Only the PVP functionalised silver nanoparticles showed a size distribution change in all of the culture media that is so small that it could be attributed to solely protein adsorption without notable agglomeration. Silica nanoparticles were found to be the most sensitive to interaction with serum containing CCM, showing massive concentration and time dependent agglomeration strongly affected by the CCM composition. Extensive agglomeration might lead also to the accelerated sedimentation of the particles changing drastically the true, effective dose that the cells will receive under in vitro conditions1, 2. Thus, it has to be investigated in more detail and taken in account when designing in vitro experiments in the next phase of the project.JRC.F.2-Consumer Products Safet

The SARS-CoV-2 Nucleoprotein Induces Innate Memory in Human Monocytes

The interaction of SARS-CoV-2 with the human immune system is at the basis of the positive or negative outcome of the infection. Monocytes and macrophages, which are major innate immune/inflammatory effector cells, are not directly infected by SARS-CoV-2, however they can react to the virus and mount a strong reaction. Whether this first interaction and reaction may bias innate reactivity to re-challenge, a phenomenon known as innate memory, is currently unexplored and may be part of the long-term sequelae of COVID-19. Here, we have tested the capacity of SARS-CoV-2 and some of its proteins to induce innate memory in human monocytes in vitro. Our preliminary results show that the Spike protein subunits S1 and S2 and the entire heat-inactivated virus have no substantial effect. Conversely, monocytes pre-exposed to the nucleocapsid N protein react to subsequent viral or bacterial challenges with an increased production of anti-inflammatory IL-1Ra, a response profile suggesting a milder response to new infections

The Certification of Reference Materials of Maize Seed Powder with different Mass Fractions of the Maize Event 3272. Certified Reference Materials ERM-BF420 (ERM-BF420a, ERM-BF420b, ERM-BF420c)

This report describes the processing and certification of maize Certified Reference Materials (CRMs) with different mass fractions of genetically modified (GM) Event 3272 maize seed powder (CRMs ERM-BF420a, ERM-BF420b, ERM-BF420c). The CRMs are intended to be used for the quality control or calibration of methods for the quantification of the Event 3272 maize mass fraction in food and feed. The GM maize mass fractions of ERM-BF420 were verified by an event-specific real-time polymerase chain reaction (rt-PCR) method. The CRMs are available in glass bottles containing 1 g of dried maize powder closed under argon atmosphere.JRC.D.2-Reference material

Changes in Caco-2 cells transcriptome profiles upon exposure to gold nanoparticles

Abstract Higher efficacy and safety of nano gold therapeutics require examination of cellular responses to gold nanoparticles (AuNPs). In this work we compared cellular uptake, cytotoxicity and RNA expression patterns induced in Caco-2 cells exposed to AuNP (5 and 30 nm). Cellular internalization was dose and time-dependent for both AuNPs. The toxicity was observed by colony forming efficiency (CFE) and not by Trypan blue assay, and exclusively for 5 nm AuNPs, starting at the concentration of 200 μM (24 and 72 h of exposure). The most pronounced changes in gene expression (Agilent microarrays) were detected at 72 h (300 μM) of exposure to AuNPs (5 nm). The biological processes affected by smaller AuNPs were: RNA/zinc ion/transition metal ion binding (decreased), cadmium/copper ion binding and glutathione metabolism (increased). Some Nrf2 responsive genes (several metallothioneins, HMOX, G6PD, OSGIN1 and GPX2) were highly up regulated. Members of the selenoproteins were also differentially expressed. Our findings indicate that exposure to high concentration of AuNPs (5 nm) induces metal exposure, oxidative stress signaling pathways, and might influence selenium homeostasis. Some of detected cellular responses might be explored as potential enhancers of anti-cancer properties of AuNPs based nanomedicines

Dispersion Behaviour of Silica Nanoparticles in Biological Media and Its Influence on Cellular Uptake

Given the increasing variety of manufactured nanomaterials, suitable, robust, standardized in vitro screening methods are needed to study the mechanisms by which they can interact with biological systems. The in vitro evaluation of interactions of nanoparticles (NPs) with living cells is challenging due to the complex behaviour of NPs, which may involve dissolution, aggregation, sedimentation and formation of a protein corona. These variable parameters have an influence on the surface properties and the stability of NPs in the biological environment and therefore also on the interaction of NPs with cells. We present here a study using 30 nm and 80 nm fluorescently-labelled silicon dioxide NPs (Rubipy-SiO2 NPs) to evaluate the NPs dispersion behaviour up to 48 hours in two different cellular media either supplemented with 10% of serum or in serum-free conditions. Size-dependent differences in dispersion behaviour were observed and the influence of the living cells on NPs stability and deposition was determined. Using flow cytometry and fluorescence microscopy techniques we studied the kinetics of the cellular uptake of Rubipy-SiO2 NPs by A549 and CaCo-2 cells and we found a correlation between the NPs characteristics in cell media and the amount of cellular uptake. Our results emphasize how relevant and important it is to evaluate and to monitor the size and agglomeration state of nanoparticles in the biological medium, in order to interpret correctly the results of the in vitro toxicological assays.JRC.I.4-Nanobioscience