Nano-sized zinc oxide and silver, but not titanium dioxide, induce innate and adaptive immunity and antiviral response in differentiated THP-1 cells

Nanoparticle‑based antiviral strategies to combat the influenza virus (Review)

The rapid availability of effective antiviral treatments would be beneficial during the early phases of a pandemic, as they could reduce viral loads and control serious infections until antigenic vaccines become widely available. One promising alternative therapy to combat pandemics is nanotechnology, which has the potential to inhibit a wide variety of viruses, including the influenza virus. This review summarizes the recent progress using gold, copper, silver, silicone, zinc and selenium nanoparticles, since these materials have shown remarkable antiviral capacity against influenza A virus.

Dental implant material related changes in molecular signatures in peri-implantitis - A systematic review of omics in-vivo studies

OBJECTIVE

Titanium particles have been shown in in-vitro studies to lead to the activation of specific pathways, this work aims to systematically review in- vivo studies examining peri-implant and periodontal tissues at the transcriptome, proteome, epigenome and genome level to reveal implant material-related processes favoring peri-implantitis development investigated in animal and human trials.

METHODS

Inquiring three literature databases (Medline, Embase, Cochrane) a systematic search based on a priori defined PICOs was conducted: '-omics' studies comparing molecular signatures in healthy and infected peri-implant sites and/or healthy and periodontitis-affected teeth in animals/humans. After risk of bias assessments, lists of differentially expressed genes and results of functional enrichment analyses were compiled whenever possible.

RESULTS

Out of 2187 screened articles 9 publications were deemed eligible. Both healthy and inflamed peri-implant tissues showed distinct gene expression patterns compared to healthy/diseased periodontal tissues in animal (n = 4) or human studies (n = 5), with immune response, bone metabolism and oxidative stress being affected the most. Due to the lack of available re-analyzable data and inconsistency in methodology of the eligible studies, integrative analyses on differential gene expression were not applicable CONCLUSION: The differences of transcriptomic signatures in between peri-implant lesions compared to periodontal tissue might be related to titanium particles arising from dental implants and are in line with the in-vitro data recently published by our group. Nevertheless, limitations emerge from small sample sizes of included studies and insufficient publication of re-analyzable data.

Titanium-Dioxide-Nanoparticle-Embedded Polyelectrolyte Multilayer as an Osteoconductive and Antimicrobial Surface Coating

Bioactive surface coatings have retained the attention of researchers and physicians due to their versatility and range of applications in orthopedics, particularly in infection prevention. Antibacterial metal nanoparticles (mNPs) are a promising therapeutic, with vast application opportunities on orthopedic implants. The current research aimed to construct a polyelectrolyte multilayer on a highly porous titanium implant using alternating thin film coatings of chitosan and alginate via the layer-by-layer (LbL) self-assembly technique, along with the incorporation of silver nanoparticles (AgNPs) or titanium dioxide nanoparticles (TiO2NPs), for antibacterial and osteoconductive activity. These mNPs were characterized for their physicochemical properties using quartz crystal microgravimetry with a dissipation system, nanoparticle tracking analysis, scanning electron microscopy, and atomic force microscopy. Their cytotoxicity and osteogenic differentiation capabilities were assessed using AlamarBlue and alkaline phosphatase (ALP) activity assays, respectively. The antibiofilm efficacy of the mNPs was tested against Staphylococcus aureus. The LbL polyelectrolyte coating was successfully applied to the porous titanium substrate. A dose-dependent relationship between nanoparticle concentration and ALP as well as antibacterial effects was observed. TiO2NP samples were also less cytotoxic than their AgNP counterparts, although similarly antimicrobial. Together, these data serve as a proof-of-concept for a novel coating approach for orthopedic implants with antimicrobial and osteoconductive properties.

Nanoparticles-induced potential toxicity on human health: Applications, toxicity mechanisms, and evaluation models

Nanoparticles (NPs) have become one of the most popular objects of scientific study during the past decades. However, despite wealth of study reports, still there is a gap, particularly in health toxicology studies, underlying mechanisms, and related evaluation models to deeply understanding the NPs risk effects. In this review, we first present a comprehensive landscape of the applications of NPs on health, especially addressing the role of NPs in medical diagnosis, therapy. Then, the toxicity of NPs on health systems is introduced. We describe in detail the effects of NPs on various systems, including respiratory, nervous, endocrine, immune, and reproductive systems, and the carcinogenicity of NPs. Furthermore, we unravels the underlying mechanisms of NPs including ROS accumulation, mitochondrial damage, inflammatory reaction, apoptosis, DNA damage, cell cycle, and epigenetic regulation. In addition, the classical study models such as cell lines and mice and the emerging models such as 3D organoids used for evaluating the toxicity or scientific study are both introduced. Overall, this review presents a critical summary and evaluation of the state of understanding of NPs, giving readers more better understanding of the NPs toxicology to remedy key gaps in knowledge and techniques.

Nanomedicine for drug resistant pathogens and COVID-19 using mushroom nanocomposite inspired with bacteriocin – A Review

Multidrug resistant (MDR) pathogens have become a major global health challenge and have severely threatened the health of society. Current conditions have gotten worse as a result of the COVID-19 pandemic, and infection rates in the future will rise. It is necessary to design, respond effectively, and take action to address these challenges by investigating new avenues. In this regard, the fabrication of metal NPs utilized by various methods, including green synthesis using mushroom, is highly versatile, cost-effective, eco-compatible, and superior. In contrast, biofabrication of metal NPs can be employed as a powerful weapon against MDR pathogens and have immense biomedical applications. In addition, the advancement in nanotechnology has made possible to modify the nanomaterials and enhance their activities. Metal NPs with biomolecules composite to prevents their microbial adhesion and kills the microbial pathogens through biofilm formation. Bacteriocin is an excellent antimicrobial peptide that works well as an augmentation substance to boost the antimicrobial effects. As a result, we concentrate on the creation of new, eco-compatible mycosynthesized metal NPs with bacteriocin nanocomposite via electrostatic, covalent, or non-covalent bindings. The synergistic benefits of metal NPs with bacteriocin to combat MDR pathogens and COVID-19, as well as other biomedical applications, are discussed in this review. Moreover, the importance of the adverse outcome pathway (AOP) in risk analysis of manufactured metal nanocomposite nanomaterial and their future possibilities also discussed.

Transcriptomic Profiling the Effects of Airway Exposure of Zinc Oxide and Silver Nanoparticles in Mouse Lungs

Consumers and manufacturers are exposed to nanosized zinc oxide (nZnO) and silver particles (nAg) via airways, but their biological effects are still not fully elucidated. To understand the immune effects, we exposed mice to 2, 10, or 50 μg of nZnO or nAg by oropharyngeal aspiration and analyzed the global gene expression profiles and immunopathological changes in the lungs after 1, 7, or 28 days. Our results show that the kinetics of responses varied in the lungs. Exposure to nZnO resulted in the highest accumulation of F4/80- and CD3-positive cells, and the largest number of differentially expressed genes (DEGs) were identified after day 1, while exposure to nAg caused peak responses at day 7. Additionally, nZnO mainly activated the innate immune responses leading to acute inflammation, whereas the nAg activated both innate and adaptive immune pathways, with long-lasting effects. This kinetic-profiling study provides an important data source to understand the cellular and molecular processes underlying nZnO- and nAg-induced transcriptomic changes, which lead to the characterization of the corresponding biological and toxicological effects of nZnO and nAg in the lungs. These findings could improve science-based hazard and risk assessment and the development of safe applications of engineered nanomaterials (ENMs), e.g., in biomedical applications.

Antitumor Activity of Chitosan-Coated Iron Oxide Nanocomposite Against Hepatocellular Carcinoma in Animal Models

Hepatocellular carcinoma (HCC) is among the most prevalent and lethal cancers worldwide. Chitosan-coated iron oxide nanocomposite (Fe₃O₄/Cs) is a promising bio-nanomaterial for many biological applications. The objective of this research was to evaluate the anticancer efficacy of Fe₃O₄/Cs against HCC in animal models. Fe₃O₄ nanoparticles were prepared and added to chitosan solution; then, the mixture was exposed to gamma radiation at a dose of 20 kGy. Rats have received diethylnitrosamine (DEN) orally at a dose of 20 mg/kg body weight 5 times per week during a period of 10 weeks to induce HCC and then have received Fe₃O₄/Cs intraperitoneal injection at a dose of 50 mg/kg body weight 3 times per week during a period of 4 weeks. After the last dose of Fe₃O₄/Cs administration, animals were sacrificed. DEN induced upregulation of PI3K/Akt/mTOR and MAPK (ERK, JNK, P38) signaling pathways and inflammatory markers (TLR4, iNOS, and TNF-α). DEN also decreases cleaved caspase-3 and increases liver enzymes (ALT, AST, and GGT) activities. Administration of Fe₃O₄/Cs significantly ameliorated the above-mentioned parameters.

Dental implant material related changes in molecular signatures in peri-implantitis - A systematic review and integrative analysis of omics in-vitro studies

OBJECTIVE

Since peri-implantitis differs clinically and histopathologically from periodontitis, implant wear debris is considered to play a role in the destructive processes. This work aims to systematically review if titanium particles affect oral-related cells through changes in molecular signatures (e.g., transcriptome, proteome, epigenome), thereby promoting peri-implantitis.

METHODS

Leveraging three literature databases (Medline, Embase, Cochrane) a systematic search based on a priori defined PICOs was conducted: '-omics' studies examining titanium exposure in oral-related cells. After risk of bias assessments, lists of differentially expressed genes, proteins, and results of functional enrichment analyses were compiled. The significance of overlapping genes across multiple studies was assessed via Monte Carlo simulation and their ranking was verified using rank aggregation.

RESULTS

Out of 2104 screened articles we found 12 eligible publications. A significant overlap of gene expression in oral-related cells exposed to titanium particles was found in four studies. Furthermore, changes in biological processes like immune/inflammatory or stress response as well as toll-like receptor (TLR) and mitogen-activated protein kinase (MAPK) signaling pathways were linked to titanium in transcriptome and proteome studies. Epigenetic changes caused by titanium were detected but inconsistent.

CONCLUSION

An influence of titanium implant wear debris on the development and progression of peri-implantitis is plausible but needs to be proven in further studies. Limitations arise from small sample sizes of included studies and insufficient publication of re-analyzable data.

Oral exposure to Ag or TiO2 nanoparticles perturbed gut transcriptome and microbiota in a mouse model of ulcerative colitis

Silver (nAg) and titanium dioxide (nTiO₂) nanoparticles improve texture, flavour or anti-microbial properties of various food products and packaging materials. Despite their increased oral exposure, their potential toxicities in the dysfunctional intestine are unclear. Here, the effects of ingested nAg or nTiO₂ on inflamed colon were revealed in a mouse model of chemical-induced acute ulcerative colitis. Mice (eight/group) were exposed to nAg or nTiO₂ by oral gavage for 10 consecutive days. We characterized disease phenotypes, histology, and alterations in colonic transcriptome (RNA sequencing) and gut microbiome (16S sequencing). Oral exposure to nAg caused only minor changes in phenotypic hallmarks of colitic mice but induced extensive responses in gene expression enriching processes of apoptotic cell death and RNA metabolism. Instead, ingested nTiO₂ yielded shorter colon, aggravated epithelial hyperplasia and deeper infiltration of inflammatory cells. Both nanoparticles significantly changed the gut microbiota composition, resulting in loss of diversity and increase of potential pathobionts. They also increased colonic mucus and abundance of Akkermansia muciniphila. Overall, nAg and nTiO₂ induce dissimilar immunotoxicological changes at the molecular and microbiome level in the context of colon inflammation. The results provide valuable information for evaluation of utilizing metallic nanoparticles in food products for the vulnerable population.

Antiviral potential of nanoparticles for the treatment of Coronavirus infections

BACKGROUND

On 31st December 2019 in Wuhan, China, severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), was acknowledged. This virus spread quickly throughout the world causing a global pandemic. The World Health Organization declared COVID-19 a pandemic disease on 11th March 2020. Since then, the whole world has come together and have developed several vaccines against this deadly virus. Similarly, several alternative searches for pandemic disease therapeutics are still ongoing. One of them has been identified as nanotechnology. It has demonstrated significant promise for detecting and inhibiting a variety of viruses, including coronaviruses. Several nanoparticles, including gold nanoparticles, silver nanoparticles, quantum dots, carbon dots, graphene oxide nanoparticles, and zinc oxide nanoparticles, have previously demonstrated remarkable antiviral activity against a diverse array of viruses.

OBJECTIVE

This review aims to provide a basic and comprehensive overview of COVID-19's initial global outbreak and its mechanism of infiltration into human host cells, as well as the detailed mechanism and inhibitory effects of various nanoparticles against this virus. In addition to nanoparticles, this review focuses on the role of several antiviral drugs used against COVID-19 to date.

CONCLUSION

COVID-19 has severely disrupted the social and economic lives of people all over the world. Due to a lack of adequate medical facilities, countries have struggled to maintain control of the situation. Neither a drug nor a vaccine has a 100% efficacy rate. As a result, nanotechnology may be a better therapeutic alternative for this pandemic disease.

Metal and metal oxide-based antiviral nanoparticles: Properties, mechanisms of action, and applications

Certain types of metal-based nanoparticles are effective antiviral agents when used in their original form ("bare") or after their surfaces have been functionalized ("modified"), including those comprised of metals (e.g., silver) and metal oxides (e.g., zinc oxide, titanium dioxide, or iron dioxide). These nanoparticles can be prepared with different sizes, morphologies, surface chemistries, and charges, which leads to different antiviral activities. They can be used as aqueous dispersions or incorporated into composite materials, such as coatings or packaging materials. In this review, we provide an overview of the design, preparation, and characterization of metal-based nanoparticles. We then discuss their potential mechanisms of action against various kinds of viruses. Finally, the applications of some of the most common metal and metal oxide nanoparticles are discussed, including those fabricated from silver, zinc oxide, iron oxide, and titanium dioxide. In general, the major antiviral mechanisms of metal and metal oxide nanoparticles have been observed to be 1) attachment of nanoparticles to surface moieties of viral particles like spike glycoproteins, that disrupt viral attachment and uncoating in host cells; 2) generation of reactive oxygen species (ROS) that denature viral macromolecules such as nucleic acids, capsid proteins, and/or lipid envelopes; and 3) inactivation of viral glycoproteins by the disruption of the disulfide bonds of viral proteins. Several physicochemical properties of metal and metal oxide nanoparticles including size, shape, zeta potential, stability in physiological conditions, surface modification, and porosity can all impact the antiviral efficacy of the nanoparticles.

Nanotechnology for the management of COVID-19 during the pandemic and in the post-pandemic era

Following the global COVID-19 pandemic, nanotechnology has been at the forefront of research efforts and enables the fast development of diagnostic tools, vaccines and antiviral treatment for this novel virus (SARS-CoV-2). In this review, we first summarize nanotechnology with regard to the detection of SARS-CoV-2, including nanoparticle-based techniques such as rapid antigen testing, and nanopore-based sequencing and sensing techniques. Then we investigate nanotechnology as it applies to the development of COVID-19 vaccines and anti-SARS-CoV-2 nanomaterials. We also highlight nanotechnology for the post-pandemic era, by providing tools for the battle with SARS-CoV-2 variants and for enhancing the global distribution of vaccines. Nanotechnology not only contributes to the management of the ongoing COVID-19 pandemic but also provides platforms for the prevention, rapid diagnosis, vaccines and antiviral drugs of possible future virus outbreaks.

Silver Nanoparticles Inhibit Metastasis of 4T1 Tumor in Mice after Intragastric but Not Intravenous Administration

The potential anticancer activity of different silver nanoformulations is increasingly recognized. In the present work, we use the model of 4T1 tumor in BALB/ccmdb immunocompetent mice to analyze the impact of citrate- and PEG-coated silver nanoparticles (AgNPs) on the development and metastatic potential of breast cancer. One group of mice was intragastrically administered with 1 mg/kg body weight (b.w.) of AgNPs daily from day 1 to day 14 after cancer cells implantation (total dose 14 mg/kg b.w.). The second group was intravenously administered twice with 1 or 5 mg/kg b.w. of AgNPs. A tendency for lowering tumor volume on day 21 (mean volumes 491.31, 428.88, and 386.83 mm³ for control, AgNPs-PEG, and AgNPs-citrate, respectively) and day 26 (mean volumes 903.20, 764.27, and 672.62 mm³ for control, AgNPs-PEG, and AgNPs-citrate, respectively) has been observed in mice treated intragastrically, but the effect did not reach the level of statistical significance. Interestingly, in mice treated intragastrically with citrate-coated AgNPs, the number of lung metastases was significantly lower, as compared to control mice (the mean number of metastases 18.89, 14.90, and 8.03 for control, AgNPs-PEG, and AgNPs-citrate, respectively). No effect of AgNPs treatment on the number of lung metastases was observed after intravenous administration (the mean number of metastases 12.44, 9.86, 12.88, 11.05, and 10.5 for control, AgNPs-PEG 1 mg/kg, AgNPs-PEG 5 mg/kg, AgNPs-citrate 1 mg/kg, and AgNPs-citrate 5 mg/kg, respectively). Surprisingly, inhibition of metastasis was not accompanied by changes in the expression of genes associated with epithelial–mesenchymal transition. Instead, changes in the expression of inflammation-related genes were observed. The presented results support the antitumor activity of AgNPs in vivo, but the effect was limited to the inhibition of metastasis. Moreover, our results clearly point to the importance of AgNPs coating and route of administration for its anticancer activity. Finally, our study supports the previous findings that antitumor AgNPs activity may depend on the activation of the immune system and not on the direct action of AgNPs on cancer cells.

Transcriptomics-Based Investigation of Molecular Mechanisms Underlying Apoptosis Induced by ZnO Nanoparticles in Human Diffuse Large B-Cell Lymphoma

Introduction

Zinc oxide nanoparticles (ZnO NPs) show anti-cancer activity. Diffuse Large B-cell Lymphoma (DLBCL) is a type of B-cell malignancies with unsatisfying treatment outcomes. This study was set to assess the potential of ZnO NPs to selectively induce apoptosis in human DLBCL cells (OCI-LY3), and to describe possible molecular mechanisms of action.

Methods

The impact of ZnO NPs on DLBCL cells and normal peripheral blood mononuclear cells (PBMCs) was studied using cytotoxicity assay and flow-cytometry. Transcriptomics analysis was conducted to identify ZnO NPs-dependent changes in the transcriptomic profiles of DLBCL cells.

Results

ZnO NPs selectively induced apoptosis in DLBCL cells, and caused changes in their transcriptomes. Deferential gene expression (DGE) with fold change (FC) ≥3 and p ≤ 0.008 with corrected p ≤ 0.05 was identified for 528 genes; 125 genes were over-expressed and 403 genes were under-expressed in ZnO NPs-treated DLBCL cells. The over-expressed genes involved in biological processes and pathways like stress response to metal ion, cellular response to zinc ion, metallothioneins bind metals, oxidative stress, and negative regulation of growth. In contrast, the under-expressed genes were implicated in DNA packaging complex, signaling by NOTCH, negative regulation of gene expression by epigenetic, signaling by WNT, M phase of cell cycle, and telomere maintenance. Setting the FC to ≥1.5 with p ≤ 0.05 and corrected p ≤ 0.1 showed ZnO NPs to induce over-expression of anti-oxidant genes and under-expression of oncogenes; target B-cell receptor (BCR) signaling pathway and NF-κB pathway; and promote apoptosis by intrinsic and extrinsic pathways.

Discussion

Overall, ZnO NPs selectively induced apoptosis in DLBCL cells, and possible molecular mechanisms of action were described.

Zinc associated nanomaterials and their intervention in emerging respiratory viruses: Journey to the field of biomedicine and biomaterials

Respiratory viruses represent a severe public health risk worldwide, and the research contribution to tackle the current pandemic caused by the SARS-CoV-2 is one of the main targets among the scientific community. In this regard, experts from different fields have gathered to confront this catastrophic pandemic. This review illustrates how nanotechnology intervention could be valuable in solving this difficult situation, and the state of the art of Zn-based nanostructures are discussed in detail. For virus detection, learning from the experience of other respiratory viruses such as influenza, the potential use of Zn nanomaterials as suitable sensing platforms to recognize the S1 spike protein in SARS-CoV-2 are shown. Furthermore, a discussion about the antiviral mechanisms reported for ZnO nanostructures is included, which can help develop surface disinfectants and protective coatings. At the same time, the properties of Zn-based materials as supplements for reducing viral activity and the recovery of infected patients are illustrated. Within the scope of noble adjuvants to improve the immune response, the ZnO NPs properties as immunomodulators are explained, and potential prototypes of nanoengineered particles with metallic cations (like Zn2+) are suggested. Therefore, using Zn-associated nanomaterials from detection to disinfection, supplementation, and immunomodulation opens a wide area of opportunities to combat these emerging respiratory viruses. Finally, the attractive properties of these nanomaterials can be extrapolated to new clinical challenges.

A New Look at the Effects of Engineered ZnO and TiO2 Nanoparticles: Evidence from Transcriptomics Studies

Titanium dioxide (TiO2) and zinc oxide (ZnO) nanoparticles (NPs) have attracted a great deal of attention due to their excellent electrical, optical, whitening, UV-adsorbing and bactericidal properties. The extensive production and utilization of these NPs increases their chances of being released into the environment and conferring unintended biological effects upon exposure. With the increasingly prevalent use of the omics technique, new data are burgeoning which provide a global view on the overall changes induced by exposures to NPs. In this review, we provide an account of the biological effects of ZnO and TiO2 NPs arising from transcriptomics in in vivo and in vitro studies. In addition to studies on humans and mice, we also describe findings on ecotoxicology-related species, such as Danio rerio (zebrafish), Caenorhabditis elegans (nematode) or Arabidopsis thaliana (thale cress). Based on evidence from transcriptomics studies, we discuss particle-induced biological effects, including cytotoxicity, developmental alterations and immune responses, that are dependent on both material-intrinsic and acquired/transformed properties. This review seeks to provide a holistic insight into the global changes induced by ZnO and TiO2 NPs pertinent to human and ecotoxicology.

Synergistic Antibacterial Effect of Zinc Oxide Nanoparticles and Polymorphonuclear Neutrophils

Zinc oxide nanoparticles (ZnONPs) are inorganic nano-biomaterials with excellent antimicrobial properties. However, their effects on the anti-infection ability of the innate immune system remains poorly understood. The aim of the present study was to explore the potential immunomodulatory effects of ZnONPs on the innate immune system, represented by polymorphonuclear leukocytes (PMNs), and determine whether they can act synergistically to resist pathogen infections. In vitro experiment showed that ZnONPs not only exhibit obvious antibacterial activity at biocompatible concentrations but also enhance the antibacterial property of PMNs. In vivo experiments demonstrated the antibacterial effect of ZnONPs, accompanied by more infiltration of subcutaneous immune cells. Further ex vivo and in vitro experiments revealed that ZnONPs enhanced the migration of PMNs, promoted their bacterial phagocytosis efficiency, proinflammatory cytokine (TNF-α, IL-1β, and IL-6) expression, and reactive oxygen species (ROS) production. In summary, this study revealed potential synergistic effects of ZnONPs on PMNs to resist pathogen infection and the underlying mechanisms. The findings suggest that attempts should be made to fabricate and apply biomaterials in order to maximize their synergy with the innate immune system, thus promoting the host’s resistance to pathogen invasion.

Prediction of Skin Sensitization Potential of Silver and Zinc Oxide Nanoparticles Through the Human Cell Line Activation Test

The development of nanotechnology has propagated the use of nanoparticles (NPs) in various fields including industry, agriculture, engineering, cosmetics, or medicine. The use of nanoparticles in cosmetics and dermal-based products is increasing owing to their higher surface area and unique physiochemical properties. Silver (Ag) NPs' excellent broad-spectrum antibacterial property and zinc oxide (ZnO) NPs' ability to confer better ultraviolet (UV) protection has led to their maximal use in cosmetics and dermal products. While the consideration for use of nanoparticles is increasing, concerns have been raised regarding their potential negative impacts. Although used in various dermal products, Ag and ZnO NPs' skin sensitization (SS) potential has not been well-investigated using in vitro alternative test methods. The human Cell Line Activation Test (h-CLAT) that evaluates the ability of chemicals to upregulate the expression of CD86 and CD54 in THP-1 cell line was used to assess the skin sensitizing potential of these NPs. The h-CLAT assay was conducted following OECD TG 442E. NPs inducing relative fluorescence intensity of CD86 ≥ 150% and/or CD54 ≥ 200% in at least two out of three independent runs were predicted to be positive. Thus, Ag (20, 50, and 80 nm) NPs and ZnO NPs were all predicted to be positive in terms of SS possibility using the h-CLAT prediction model. Although further confirmatory tests addressing other key events (KEs) of SS adverse outcome pathway (AOP) should be carried out, this study gave an insight into the need for cautious use of Ag and ZnO NPs based skincare or dermal products owing to their probable skin sensitizing potency.

Profiling Non-Coding RNA Changes Associated with 16 Different Engineered Nanomaterials in a Mouse Airway Exposure Model

Perturbations in cellular molecular events and their associated biological processes provide opportunities for hazard assessment based on toxicogenomic profiling. Long non-coding RNAs (lncRNAs) are transcribed from DNA but are typically not translated into full-length proteins. Via epigenetic regulation, they play important roles in organismal response to environmental stress. The effects of nanoparticles on this important part of the epigenome are understudied. In this study, we investigated changes in lncRNA associated with hazardous inhalatory exposure of mice to 16 engineered nanomaterials (ENM)–4 ENM (copper oxide, multi-walled carbon nanotubes, spherical titanium dioxide, and rod-like titanium dioxide particles) with 4 different surface chemistries (pristine, COOH, NH₂, and PEG). Mice were exposed to 10 µg of ENM by oropharyngeal aspiration for 4 consecutive days, followed by cytological analyses and transcriptomic characterization of whole lung tissues. The number of significantly altered non-coding RNA transcripts, suggestive of their degrees of toxicity, was different for each ENM type. Particle surface chemistry and shape also had varying effects on lncRNA expression. NH₂ and PEG caused the strongest and weakest responses, respectively. Via correlational analyses to mRNA expression from the same samples, we could deduce that significantly altered lncRNAs are potential regulators of genes involved in mitotic cell division and DNA damage response. This study sheds more light on epigenetic mechanisms of ENM toxicity and also emphasizes the importance of the lncRNA superfamily as toxicogenomic markers of adverse ENM exposure.

Differential influence of Streptococcus mitis on host response to metals in reconstructed human skin and oral mucosa

BACKGROUND

Skin and oral mucosa are continuously exposed to potential metal sensitizers while hosting abundant microbes, which may influence the host response to sensitizers. This host response may also be influenced by the route of exposure that is skin or oral mucosa, due to their different immune properties.

OBJECTIVE

Determine how commensal Streptococcus mitis influences the host response to nickel sulfate (sensitizer) and titanium(IV) bis(ammonium lactato)dihydroxide (questionable sensitizer) in reconstructed human skin (RHS) and gingiva (RHG).

METHODS

RHS/RHG was exposed to nickel or titanium, in the presence or absence of S. mitis for 24 hours. Histology, cytokine secretion, and Toll-like receptors (TLRs) expression were assessed.

RESULTS

S. mitis increased interleukin (IL)-6, CXCL8, CCL2, CCL5, and CCL20 secretion in RHS but not in RHG; co-application with nickel further increased cytokine secretion. In contrast, titanium suppressed S. mitis-induced cytokine secretion in RHS and had no influence on RHG. S. mitis and metals differentially regulated TLR1 and TLR4 in RHS, and predominantly TLR4 in RHG.

CONCLUSION

Co-exposure of S. mitis and nickel resulted in a more potent innate immune response in RHS than in RHG, whereas titanium remained inert. These results indicate the important influence of commensal microbes and the route of exposure on the host's response to metals.

In Vitro and In Vivo Models for Evaluating the Oral Toxicity of Nanomedicines

Toxicity studies for conventional oral drug formulations are standardized and well documented, as required by the guidelines of administrative agencies such as the US Food & Drug Administration (FDA), the European Medicines Agency (EMA) or European Medicines Evaluation Agency (EMEA), and the Japanese Pharmaceuticals and Medical Devices Agency (PMDA). Researchers tend to extrapolate these standardized protocols to evaluate nanoformulations (NFs) because standard nanotoxicity protocols are still lacking in nonclinical studies for testing orally delivered NFs. However, such strategies have generated many inconsistent results because they do not account for the specific physicochemical properties of nanomedicines. Due to their tiny size, accumulated surface charge and tension, sizeable surface-area-to-volume ratio, and high chemical/structural complexity, orally delivered NFs may generate severe topical toxicities to the gastrointestinal tract and metabolic organs, including the liver and kidney. Such toxicities involve immune responses that reflect different mechanisms than those triggered by conventional formulations. Herein, we briefly analyze the potential oral toxicity mechanisms of NFs and describe recently reported in vitro and in vivo models that attempt to address the specific oral toxicity of nanomedicines. We also discuss approaches that may be used to develop nontoxic NFs for oral drug delivery.

Transcriptomics-Based Characterization of the Toxicity of ZnO Nanoparticles Against Chronic Myeloid Leukemia Cells

INTRODUCTION

Zinc oxide nanoparticles (ZnO NPs) have recently attracted attention as potential anti-cancer agents. To the best of our knowledge, the toxicity of ZnO NPs against human chronic myeloid leukemia cells (K562 cell line) has not been studied using transcriptomics approach.

OBJECTIVE

The goals of this study were to evaluate the capability of ZnO NPs to induce apoptosis in human chronic myeloid leukemia cells (K562 cells) and to investigate the putative mechanisms of action.

METHODS

We used viability assay and flowcytometry coupled with Annexin V-FITC and propidium iodide to investigate the toxicity of ZnO NPs on K562 cells and normal peripheral blood mononuclear cells. Next we utilized a DNA microarray-based transcriptomics approach to characterize the ZnO NPs-induced changes in the transcriptome of K562 cells.

RESULTS

ZnO NPs exerted a selective toxicity (mainly by apoptosis) on the leukemic cells (p≤0.005) and altered their transcriptome; 429 differentially expressed genes (DEGs) with fold change (FC)≥4 and p≤0.008 with corrected p≤0.05 were identified in K562 cells post treatment with ZnO NPs. The over-expressed genes were implicated in "response to zinc", "response to toxic substance" and "negative regulation of growth" (corrected p≤0.05). In contrast, the repressed genes positively regulated "cell proliferation", "cell migration", "cell adhesion", "receptor signaling pathway via JAK-STAT" and "phosphatidylinositol 3-kinase signaling" (corrected p≤0.05). Lowering the FC to ≥1.5 with p≤0.05 and corrected p≤0.1 showed that ZnO NPs over-expressed the anti-oxidant defense system, drove K562 cells to undergo mitochondrial-dependent apoptosis, and targeted NF-κB pathway.

CONCLUSION

Taken together, our findings support the earlier studies that reported anti-cancer activity of ZnO NPs and revealed possible molecular mechanisms employed by ZnO NPs to induce apoptosis in K562 cells.

Mechanistic Similarities between 3D Human Bronchial Epithelium and Mice Lung, Exposed to Copper Oxide Nanoparticles, Support Non-Animal Methods for Hazard Assessment

The diversity and increasing prevalence of products derived from engineered nanomaterials (ENM), warrants implementation of non-animal approaches to health hazard assessment for ethical and practical reasons. Although non-animal approaches are becoming increasingly popular, there are almost no studies of side-by-side comparisons with traditional in vivo assays. Here, transcriptomics is used to investigate mechanistic similarities between healthy/asthmatic models of 3D air-liquid interface (ALI) cultures of donor-derived human bronchial epithelia cells, and mouse lung tissue, following exposure to copper oxide ENM. Only 19% of mouse lung genes with human orthologues are not expressed in the human 3D ALI model. Despite differences in taxonomy and cellular complexity between the systems, a core subset of matching genes cluster mouse and human samples strictly based on ENM dose (exposure severity). Overlapping gene orthologue pairs are highly enriched for innate immune functions, suggesting an important and maybe underestimated role of epithelial cells. In conclusion, 3D ALI models based on epithelial cells, are primed to bridge the gap between traditional 2D in vitro assays and animal models of airway exposure, and transcriptomics appears to be a unifying dose metric that links in vivo and in vitro test systems.

Hard Nanomaterials in Time of Viral Pandemics

The SARS-Cov-2 pandemic has spread worldwide during 2020, setting up an uncertain start of this decade. The measures to contain infection taken by many governments have been extremely severe by imposing home lockdown and industrial production shutdown, making this the biggest crisis since the second world war. Additionally, the continuous colonization of wild natural lands may touch unknown virus reservoirs, causing the spread of epidemics. Apart from SARS-Cov-2, the recent history has seen the spread of several viral pandemics such as H2N2 and H3N3 flu, HIV, and SARS, while MERS and Ebola viruses are considered still in a prepandemic phase. Hard nanomaterials (HNMs) have been recently used as antimicrobial agents, potentially being next-generation drugs to fight viral infections. HNMs can block infection at early (disinfection, entrance inhibition) and middle (inside the host cells) stages and are also able to mitigate the immune response. This review is focused on the application of HNMs as antiviral agents. In particular, mechanisms of actions, biological outputs, and limitations for each HNM will be systematically presented and analyzed from a material chemistry point-of-view. The antiviral activity will be discussed in the context of the different pandemic viruses. We acknowledge that HNM antiviral research is still at its early stage, however, we believe that this field will rapidly blossom in the next period.

Metal Nanoparticles in Infection and Immunity

Background Enthusiasm for the use of metal nanoparticles in human and veterinary medicine is high. Many articles describe the effects of metal nanoparticles on microbes in vitro, and a smaller number of articles describe effects on the immune system, which is the focus of this review. Methods Articles were retrieved by performing literature searches in Medline, of the National Institute of Medicine, as well as via Google Scholar. Results In vitro studies show that metal nanoparticles have antimicrobial effects. Some metal nanoparticles augment innate host immune defenses, such as endogenous antimicrobial peptides, and nitric oxide. Metal nanoparticles may also function as vaccine adjuvants. Metal nanoparticles can migrate to locations distant from the site of administration, however, requiring careful monitoring for toxicity. Conclusions Metal nanoparticles show a great deal of potential as immunomodulators, as well as direct antimicrobial effects. Before metal particles can be adopted as therapies; however, more studies are needed to determine how nanoparticles migrate though the body and on possible adverse effects.

Application of nanomaterials in treatment, anti-infection and detection of coronaviruses

Nanotechnology and nanomedicine have excellent potential in dealing with a range of different health problems, including viruses, which are considered to be a serious challenge in the medical field. Application of nanobiotechnology could represent a new avenue for the treatment or disinfection of viruses. There is increasing concern regarding the control of coronaviruses, among these, Middle East respiratory syndrome coronavirus, severe acute respiratory syndrome coronavirus and severe acute respiratory syndrome coronavirus-2 are well known and dangerous examples. This article aims to provide an overview of recent studies on the effectiveness of nanoparticles as diagnostic or antiviral tools against coronaviruses. The possibilities of effectively using nanomaterials as vaccines and nanosensors in this field are also presented.

Mass Cytometry and Single-Cell RNA-seq Profiling of the Heterogeneity in Human Peripheral Blood Mononuclear Cells Interacting with Silver Nanoparticles

Understanding the interactions between nanoparticles (NPs) and human immune cells is necessary for justifying their utilization in consumer products and biomedical applications. However, conventional assays may be insufficient in describing the complexity and heterogeneity of cell-NP interactions. Herein, mass cytometry and single-cell RNA-sequencing (scRNA-seq) are complementarily used to investigate the heterogeneous interactions between silver nanoparticles (AgNPs) and primary immune cells. Mass cytometry reveals the heterogeneous biodistribution of the positively charged polyethylenimine-coated AgNPs in various cell types and finds that monocytes and B cells have higher association with the AgNPs than other populations. scRNA-seq data of these two cell types demonstrate that each type has distinct responses to AgNP treatment: NRF2-mediated oxidative stress is confined to B cells, whereas monocytes show Fcγ-mediated phagocytosis. Besides the between-population heterogeneity, analysis of single-cell dose-response relationships further reveals within-population diversity for the B cells and naïve CD4⁺ T cells. Distinct subsets having different levels of cellular responses with respect to their cellular AgNP doses are found. This study demonstrates that the complementary use of mass cytometry and scRNA-seq is helpful for gaining in-depth knowledge on the heterogeneous interactions between immune cells and NPs and can be incorporated into future toxicity assessments of nanomaterials.

Metal Oxide Nanoparticles in Therapeutic Regulation of Macrophage Functions

Macrophages are components of the innate immune system that control a plethora of biological processes. Macrophages can be activated towards pro-inflammatory (M1) or anti-inflammatory (M2) phenotypes depending on the cue; however, polarization may be altered in bacterial and viral infections, cancer, or autoimmune diseases. Metal (zinc, iron, titanium, copper, etc.) oxide nanoparticles are widely used in therapeutic applications as drugs, nanocarriers, and diagnostic tools. Macrophages can recognize and engulf nanoparticles, while the influence of macrophage-nanoparticle interaction on cell polarization remains unclear. In this review, we summarize the molecular mechanisms that drive macrophage activation phenotypes and functions upon interaction with nanoparticles in an inflammatory microenvironment. The manifold effects of metal oxide nanoparticles on macrophages depend on the type of metal and the route of synthesis. While largely considered as drug transporters, metal oxide nanoparticles nevertheless have an immunotherapeutic potential, as they can evoke pro- or anti-inflammatory effects on macrophages and become essential for macrophage profiling in cancer, wound healing, infections, and autoimmunity.

Foam Cell-Derived CXCL14 Muti-Functionally Promotes Atherogenesis and Is a Potent Therapeutic Target in Atherosclerosis

CXC chemokine family has been related to atherogenesis for long. However, the relationship between CXCL14 and atherogenesis is still unclear. This study preliminarily detected CXCL14 expression at foam cells in atherosclerosis specimens by immunohistochemistry. In vitro foam cells were derived from THP-1 after phorbol-12-myristate-13-acetate (PMA) and oxidized low-density lipoprotein (ox-LDL) stimulation. Immunoblotting and qPCR convinced CXCL14 expression variation during foam cell formation. We further demonstrated that ox-LDL regulated CXCL14 expression by AP-1. AP-1 could bind to CXCL14 promoter and up-regulate CXCL14 mRNA expression. Besides, CXCL14 promoted THP-1 migration, macrophage lipid phagocytosis, and smooth muscle cell migration as well as proliferation mainly via the ERK1/2 pathway. Additionally, a CXCL14 peptide-induced immune therapy showed efficacy in ApoE^-/- mouse model. In conclusion, our study demonstrated that CXCL14 is highly up-regulated during foam cell formation and promotes atherogenesis in various ways. CXCL14 may be a potent therapeutic target for atherosclerosis.

Silver, titanium dioxide, and zinc oxide nanoparticles trigger miRNA/isomiR expression changes in THP-1 cells that are proportional to their health hazard potential

After over a decade of nanosafety research, it is indisputable that the vast majority of nano-sized particles induce a plethora of adverse cellular responses - the severity of which is linked to the material's physicochemical properties. Differentiated THP-1 cells were previously exposed for 6 h and 24 h to silver, titanium dioxide, and zinc oxide nanoparticles at the maximum molar concentration at which no more than 15% cellular cytotoxicity was observed. All three nanoparticles differed in extent of induction of biological pathways corresponding to immune response signaling and metal ion homeostasis. In this study, we integrated gene and miRNA expression profiles from the same cells to propose miRNA biomarkers of adverse exposure to metal-based nanoparticles. We employed RNA sequencing together with a quantitative strategy that also enables analysis of the overlooked repertoire of length and sequence miRNA variants called isomiRs. Whilst only modest changes in expression were observed within the first 6 h of exposure, the miRNA/isomiR (miR) profiles of each nanoparticle were unique. Via canonical correlation and pathway enrichment analyses, we identified a co-regulated miR-mRNA cluster, predicted to be highly relevant for cellular response to metal ion homeostasis. These miRs were annotated to be canonical or variant isoforms of hsa-miR-142-5p, -342-3p, -5100, -6087, -6894-3p, and -7704. Hsa-miR-5100 was differentially expressed in response to each nanoparticle in both the 6 h and 24 h exposures. Taken together, this co-regulated miR-mRNA cluster could represent potential biomarkers of sub-toxic metal-based nanoparticle exposure.

Molecular Signature of Asthma-Enhanced Sensitivity to CuO Nanoparticle Aerosols from 3D Cell Model

More than 5% of any population suffers from asthma, and there are indications that these individuals are more sensitive to nanoparticle aerosols than the healthy population. We used an air-liquid interface model of inhalation exposure to investigate global transcriptomic responses in reconstituted three-dimensional airway epithelia of healthy and asthmatic subjects exposed to pristine (nCuO) and carboxylated (nCuO^COOH) copper oxide nanoparticle aerosols. A dose-dependent increase in cytotoxicity (highest in asthmatic donor cells) and pro-inflammatory signaling within 24 h confirmed the reliability and sensitivity of the system to detect acute inhalation toxicity. Gene expression changes between nanoparticle-exposed versus air-exposed cells were investigated. Hierarchical clustering based on the expression profiles of all differentially expressed genes (DEGs), cell-death-associated DEGs (567 genes), or a subset of 48 highly overlapping DEGs categorized all samples according to "exposure severity", wherein nanoparticle surface chemistry and asthma are incorporated into the dose-response axis. For example, asthmatics exposed to low and medium dose nCuO clustered with healthy donor cells exposed to medium and high dose nCuO, respectively. Of note, a set of genes with high relevance to mucociliary clearance were observed to distinctly differentiate asthmatic and healthy donor cells. These genes also responded differently to nCuO and nCuO^COOH nanoparticles. Additionally, because response to transition-metal nanoparticles was a highly enriched Gene Ontology term (FDR 8 × 10^-13) from the subset of 48 highly overlapping DEGs, these genes may represent biomarkers to a potentially large variety of metal/metal oxide nanoparticles.

Food additives can act as triggering factors in celiac disease: Current knowledge based on a critical review of the literature

Celiac disease (CeD) is an autoimmune disorder, mainly affecting the small intestine, triggered by the ingestion of gluten with the diet in subjects with a specific genetic status. The passage of gluten peptides through the intestinal barrier, the uptake by antigen presenting cells and their presentation to T cells represent essential steps in the pathogenesis of the disease. CeD prevalence varies in different populations, but a tendency to increase has been observed in various studies in recent years. A higher amount of gluten in modern grains could explain this increased frequency, but also food processing could play a role in this phenomenon. In particular, the common use of preservatives such as nanoparticles could intervene in the pathogenesis of CeD, due to their possible effect on the integrity of the intestinal barrier, immune response or microbiota. In fact, these alterations have been reported after exposure to metal nanoparticles, which are commonly used as preservatives or to improve food texture, consistency and color. This review will focus on the interactions between several food additives and the intestine, taking into account data obtained in vitro and in vivo, and analyzing their effect in respect to the development of CeD in genetically predisposed individuals.

Analysis of Nanomaterial Toxicity by Western Blot

Western blot is a routine biochemical technique for the immunodetection of proteins in cells and tissues exposed to nanomaterials (NMs). It is a sensitive method for protein analysis that involves the solubilization and separation of proteins by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), transferring and immobilizing proteins onto a solid support, and targeted immunoprobing of a specific antigen. As a convenient and reliable research tool, the western blot plays an irreplaceable role in the era of proteomics together with mass spectrometry and protein chip. In this chapter we describe the detailed protocol for the entire process from sample preparation to quantitative measurement of target proteins.

Aluminium oxide nanoparticles induce structural changes in tau and cytotoxicity of the neuroblastoma cell line

The application of nanomaterials in the healthy system may induce some neurodegenerative diseases initiated by tau folding and neuronal cell death. Herein, aluminium oxide nanoparticles (Al₂O₃ NPs) were synthesized and characterized by XRD, TEM, DLS and zeta potential investigations. Afterwards, the interaction of Al₂O₃ NPs with tau protein was investigated by fluorescence and CD spectroscopic methods. The molecular docking and molecular dynamic were also run to explore the binding site and conformational changes of tau after interaction with Al₂O₃ cluster. Moreover, the MTT, LDH, caspase-9/-3 and flow cytometry assays were done to explore the Al₂O₃ NPs-induced cytotoxicity against SH-SY5Y cells. It was revealed that Al₂O₃ NPs bind to tau protein and form a static complex and fold the structure of tau toward a more packed structure. Molecular docking and molecular dynamic investigations revealed that NPs bind to the hydrophilic residues of the tau segments and promote some marginal structural folding of tau segment. The cellular assays displayed that Al₂O₃ NPs can elicit cell mortality through membrane leakage, caspase-9/-3 activations, and induction of both apoptosis and necrosis. This data may indicate that NPs can induce some adverse effects on the biological systems.