Intranasal Delivery of Copper Oxide Nanoparticles Induces Pulmonary Toxicity and Fibrosis in C57BL/6 mice

Nanoplatform Based Intranasal Vaccines: Current Progress and Clinical Challenges

Multiple vaccine platforms have been employed to develop the nasal SARS-CoV-2 vaccines in preclinical studies, and the dominating pipelines are viral vectored as protein-based vaccines. Among them, several viral vectored-based vaccines have entered clinical development. Nevertheless, some unsatisfactory results were reported in these clinical studies. In the face of such urgent situations, it is imperative to rapidly develop the next-generation intranasal COVID-19 vaccine utilizing other technologies. Nanobased intranasal vaccines have emerged as an approach against respiratory infectious diseases. Harnessing the power of nanotechnology, these vaccines offer a noninvasive yet potent defense against pathogens, including the threat of COVID-19. The improvements made in vaccine mucosal delivery technologies based on nanoparticles, such as lipid nanoparticles, polymeric nanoparticles, inorganic nanoparticles etc., not only provide stability and controlled release but also enhance mucosal adhesion, effectively overcoming the limitations of conventional vaccines. Hence, in this review, we overview the evaluation of intranasal vaccine and highlight the current barriers. Next, the modern delivery systems based on nanoplatforms are summarized. The challenges in clinical application of nanoplatform based intranasal vaccine are finally discussed.

MMP-3 mediates copper oxide nanoparticle-induced pulmonary inflammation and fibrosis

BACKGROUND

The increasing production and usage of copper oxide nanoparticles (Nano-CuO) raise human health concerns. Previous studies have demonstrated that exposure to Nano-CuO could induce lung inflammation, injury, and fibrosis. However, the potential underlying mechanisms are still unclear. Here, we proposed that matrix metalloproteinase-3 (MMP-3) might play an important role in Nano-CuO-induced lung inflammation, injury, and fibrosis.

RESULTS

Exposure of mice to Nano-CuO caused acute lung inflammation and injury in a dose-dependent manner, which was reflected by increased total cell number, neutrophil count, macrophage count, lactate dehydrogenase (LDH) activity, and CXCL1/KC level in bronchoalveolar lavage fluid (BALF) obtained on day 3 post-exposure. The time-response study showed that Nano-CuO-induced acute lung inflammation and injury appeared as early as day 1 after exposure, peaked on day 3, and ameliorated over time. However, even on day 42 post-exposure, the LDH activity and macrophage count were still higher than those in the control group, suggesting that Nano-CuO caused chronic lung inflammation. The Nano-CuO-induced pulmonary inflammation was further confirmed by H&E staining of lung sections. Trichrome staining showed that Nano-CuO exposure caused pulmonary fibrosis from day 14 to day 42 post-exposure with an increasing tendency over time. Increased hydroxyproline content and expression levels of fibrosis-associated proteins in mouse lungs were also observed. In addition, Nano-CuO exposure induced MMP-3 overexpression and increased MMP-3 secretion in mouse lungs. Knocking down MMP-3 in mouse lungs significantly attenuated Nano-CuO-induced acute and chronic lung inflammation and fibrosis. Moreover, Nano-CuO exposure caused sustained production of cleaved osteopontin (OPN) in mouse lungs, which was also significantly decreased by knocking down MMP-3.

CONCLUSIONS

Our results demonstrated that short-term Nano-CuO exposure caused acute lung inflammation and injury, while long-term exposure induced chronic pulmonary inflammation and fibrosis. Knocking down MMP-3 significantly ameliorated Nano-CuO-induced pulmonary inflammation, injury, and fibrosis, and also attenuated Nano-CuO-induced cleaved OPN level. Our study suggests that MMP-3 may play important roles in Nano-CuO-induced pulmonary inflammation and fibrosis via cleavage of OPN and may provide a further understanding of the mechanisms underlying Nano-CuO-induced pulmonary toxicity.

Nanoparticles and Airway Epithelial Cells: Exploring the Impacts and Methodologies in Toxicity Assessment

The production of nanoparticles has recently surged due to their varied applications in the biomedical, pharmaceutical, textile, and electronic sectors. However, this rapid increase in nanoparticle manufacturing has raised concerns about environmental pollution, particularly its potential adverse effects on human health. Among the various concerns, inhalation exposure to nanoparticles poses significant risks, especially affecting the respiratory system. Airway epithelial cells play a crucial role as the primary defense against inhaled particulate matter and pathogens. Studies have shown that nanoparticles can disrupt the airway epithelial barrier, triggering inflammatory responses, generating reactive oxygen species, and compromising cell viability. However, our understanding of how different types of nanoparticles specifically impact the airway epithelial barrier remains limited. Both in vitro cell culture and in vivo murine models are commonly utilized to investigate nanoparticle-induced cellular responses and barrier dysfunction. This review discusses the methodologies frequently employed to assess nanoparticle toxicity and barrier disruption. Furthermore, we analyze and compare the distinct effects of various nanoparticle types on the airway epithelial barrier. By elucidating the diverse responses elicited by different nanoparticles, we aim to provide insights that can guide future research endeavors in assessing and mitigating the potential risks associated with nanoparticle exposure.

Copper homeostasis dysregulation in respiratory diseases: a review of current knowledge

Cu is an essential micronutrient for various physiological processes in almost all human cell types. Given the critical role of Cu in a wide range of cellular processes, the local concentrations of Cu and the cellular distribution of Cu transporter proteins in the lung are essential for maintaining a steady-state internal environment. Dysfunctional Cu metabolism or regulatory pathways can lead to an imbalance in Cu homeostasis in the lungs, affecting both acute and chronic pathological processes. Recent studies have identified a new form of Cu-dependent cell death called cuproptosis, which has generated renewed interest in the role of Cu homeostasis in diseases. Cuproptosis differs from other known cell death pathways. This occurs through the direct binding of Cu ions to lipoylated components of the tricarboxylic acid cycle during mitochondrial respiration, leading to the aggregation of lipoylated proteins and the subsequent downregulation of Fe-S cluster proteins, which causes toxic stress to the proteins and ultimately leads to cell death. Here, we discuss the impact of dysregulated Cu homeostasis on the pathogenesis of various respiratory diseases, including asthma, chronic obstructive pulmonary disease, idiopathic interstitial fibrosis, and lung cancer. We also discuss the therapeutic potential of targeting Cu. This study highlights the intricate interplay between copper, cellular processes, and respiratory health. Copper, while essential, must be carefully regulated to maintain the delicate balance between necessity and toxicity in living organisms. This review highlights the need to further investigate the precise mechanisms of copper interactions with infections and immune inflammation in the context of respiratory diseases and explore the potential of therapeutic strategies for copper, cuproptosis, and other related effects.

The combined effects of polystyrene nanoplastics with nickel on oxidative stress and related toxic effects to earthworms from individual and cellular perspectives

Nanoplastics may adsorb other pollutants in the environment due to their high specific surface area and small size. We used earthworms as experimental organisms to evaluate the ecotoxicity of NPs and Ni combined pollution at the individual and cellular levels. The results showed that when only 20 mg/L Ni2+ was added to the combined pollution system, the antioxidant system of earthworm coelomocytes was destroyed to a certain extent, the ROS level increased, the cell viability decreased significantly, and the redox balance was destroyed. With the introduction of PS-NPs and the increase of concentration, the oxidative damage in the coelomocytes of earthworms gradually increased, and finally tended to be stable when the maximum concentration of 50 mg/L PS-NPs and Ni were exposed together. At the animal level, the activities of CAT and SOD decreased within 28 days of exposure, and the combined pollution showed a synergistic effect. At the same time, it promoted the synthesis of GST in earthworms, improved their detoxification ability and reduced oxidative damage. The changes of T-AOC and MDA showed that the combined pollution caused the accumulation of ROS and caused more serious toxicological effects. With the increase of exposure time, the antioxidant system of earthworms was continuously destroyed, and the oxidative damage was serious, which induced more serious lipid peroxidation and caused the damage of earthworm body wall structure.

Toxicity of Metal Oxide Nanoparticles: Looking through the Lens of Toxicogenomics

The impact of solubility on the toxicity of metal oxide nanoparticles (MONPs) requires further exploration to ascertain the impact of the dissolved and particulate species on response. In this study, FE1 mouse lung epithelial cells were exposed for 2-48 h to 4 MONPs of varying solubility: zinc oxide, nickel oxide, aluminum oxide, and titanium dioxide, in addition to microparticle analogues and metal chloride equivalents. Previously published data from FE1 cells exposed for 2-48 h to copper oxide and copper chloride were examined in the context of exposures in the present study. Viability was assessed using Trypan Blue staining and transcriptomic responses via microarray analysis. Results indicate material solubility is not the sole property governing MONP toxicity. Transcriptional signaling through the 'HIF-1α Signaling' pathway describes the response to hypoxia, which also includes genes associated with processes such as oxidative stress and unfolded protein responses and represents a conserved response across all MONPs tested. The number of differentially expressed genes (DEGs) in this pathway correlated with apical toxicity, and a panel of the top ten ranked DEGs was constructed (Hmox1, Hspa1a, Hspa1b, Mmp10, Adm, Serpine1, Slc2a1, Egln1, Rasd1, Hk2), highlighting mechanistic differences among tested MONPs. The HIF-1α pathway is proposed as a biomarker of MONP exposure and toxicity that can help prioritize MONPs for further evaluation and guide specific testing strategies.

Interactions between CuO NPs and PS: The release of copper ions and oxidative damage

Copper oxide nanoparticles (CuO NPs) can adversely affect lung health possibly by inducing oxidative damage through the release of copper ions. However, the migration and transformation processes of CuO NPs in lung lining fluid is still unclear, and there are still conflicting reports of redox reactions involving copper ions. To address this, we examined the release of copper ions from CuO NPs in simulated lung fluid supplemented with pulmonary surfactant (PS), and further analyzed the mechanisms of PS-CuO NPs interactions and the health hazards. The results showed that the phospholipid of PS was adsorbed on the particle surface, which not only induced aggregation of the particles but also provided a reaction environment for the interaction of PS with CuO NPs. PS was able to promote the release of ions from CuO NPs, of which the protein was a key component. Lipid peroxidation, protein destabilization, and disruption of the interfacial chemistry also occurred in the PS-CuO NPs interactions, during which copper ions were present only as divalent cations. Meanwhile, the contribution of the particle surface cannot be neglected in the oxidative damage to the lung caused by CuO NPs. Through reacting with biomolecules, CuO NPs accomplished ion release and induced oxidative damage associated with PS. This research was the first to reveal the mechanism of CuO NPs releasing copper ions and inducing lipid oxidative damage in the presence of PS, which provides a new idea of transition metal-induced health risk in human body.

Roles of Nrf2/HO-1 and ICAM-1 in the Protective Effect of Nano-Curcumin against Copper-Induced Lung Injury

Copper (Cu) is an essential trace element for maintaining normal homeostasis in living organisms. Yet, an elevated level of Cu beyond homeostatic capacity may lead to oxidative damage of cellular components in several organs, including the lungs. This work investigated the effects of curcumin (Curc) and nano-curcumin (nCurc) against Cu-induced lung injury, accenting the roles of oxidative stress, inflammation, and the nuclear factor erythroid 2-related factor/heme oxygenase-1 Nrf2/HO-1 pathway. Rats were challenged with 100 mg/kg of copper sulfate (CuSO4) while being treated with Curc or nCurc for 7 days. Cu-triggered lung oxidative stress detected as dysregulation of oxidative/antioxidant markers, a downregulation of Nrf-2/HO-1 signaling, and an increase in the inflammatory markers interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), and intracellular adhesion molecule-1 (ICAM-1). Additionally, it decreased the expression of lung-specific proteins, surfactant protein-C (SP-C), and mucin-1 (MUC-1), induced apoptosis, and caused changes in lung histology. Curc and nCurc alleviated CuSO4-induced lung injury by suppressing oxidative damage and inflammation and activating Nrf-2/HO-1. They also prevented apoptosis and restored the normal expression of SP-C and MUC-1. We concluded that nCurc exhibited superior efficacy compared with Curc in mitigating CuSO4-induced lung injury. This was associated with reduced oxidative stress, inflammation, and apoptotic responses and increased Nrf2/HO-1 signaling and expression of SP-C and MUC-1.

Recent advances in nanoparticle applications in respiratory disorders: a review

Various nanoparticles are used in the discovery of new nanomedicine to overcome the shortages of conventional drugs. Therefore, this article presents a comprehensive and up-to-date review of the effects of nanoparticle-based drugs in the treatment of respiratory disorders, including both basic and clinical studies. Databases, including PubMed, Web of Knowledge, and Scopus, were searched until the end of August 2022 regarding the effect of nanoparticles on respiratory diseases. As a new tool, nanomedicine offered promising applications for the treatment of pulmonary diseases. The basic composition and intrinsic characteristics of nanomaterials showed their effectiveness in treating pulmonary diseases. The efficiency of different nanomedicines has been demonstrated in experimental animal models of asthma, chronic obstructive pulmonary disease (COPD), pulmonary fibrosis (PF), lung cancer, lung infection, and other lung disorders, confirming their function in the improvement of respiratory disorders. Various types of nanomaterials, such as carbon nanotubes, dendrimers, polymeric nanomaterials, liposomes, quantum dots, and metal and metal oxide nanoparticles, have demonstrated therapeutic effects on respiratory disorders, which may lead to new possible remedies for various respiratory illnesses that could increase drug efficacy and decrease side effects.

Copper oxide nanoparticles: In vitro and in vivo toxicity, mechanisms of action and factors influencing their toxicology

Copper oxide nanoparticles (CuO NPs) have received increasing interest due to their distinctive properties, including small particle size, high surface area, and reactivity. Due to these properties, their applications have been expanded rapidly in various areas such as biomedical properties, industrial catalysts, gas sensors, electronic materials, and environmental remediation. However, because of these widespread uses, there is now an increased risk of human exposure, which could lead to short- and long-term toxicity. This review addresses the underlying toxicity mechanisms of CuO NPs in cells which include reactive oxygen species generation, leaching of Cu ion, coordination effects, non-homeostasis effect, autophagy, and inflammation. In addition, different key factors responsible for toxicity, characterization, surface modification, dissolution, NPs dose, exposure pathways and environment are discussed to understand the toxicological impact of CuO NPs. In vitro and in vivo studies have shown that CuO NPs cause oxidative stress, cytotoxicity, genotoxicity, immunotoxicity, neurotoxicity, and inflammation in bacterial, algal, fish, rodents, and human cell lines. Therefore, to make CuO NPs a more suitable candidate for various applications, it is essential to address their potential toxic effects, and hence, more studies should be done on the long-term and chronic impacts of CuO NPs at different concentrations to assure the safe usage of CuO NPs.

Transcriptomic profiling reveals differential cellular response to copper oxide nanoparticles and polystyrene nanoplastics in perfused human placenta

The growing nanoparticulate pollution (e.g. engineered nanoparticles (NPs) or nanoplastics) has been shown to pose potential threats to human health. In particular, sensitive populations such as pregnant women and their unborn children need to be protected from harmful environmental exposures. However, developmental toxicity from prenatal exposure to pollution particles is not yet well studied despite evidence of particle accumulation in human placenta. Our study aimed to investigate how copper oxide NPs (CuO NPs; 10-20 nm) and polystyrene nanoplastics (PS NPs; 70 nm) impact on gene expression in ex vivo perfused human placental tissue. Whole genome microarray analysis revealed changes in global gene expression profile after 6 h of perfusion with sub-cytotoxic concentrations of CuO (10 µg/mL) and PS NPs (25 µg/mL). Pathway and gene ontology enrichment analysis of the differentially expressed genes suggested that CuO and PS NPs trigger distinct cellular response in placental tissue. While CuO NPs induced pathways related to angiogenesis, protein misfolding and heat shock responses, PS NPs affected the expression of genes related to inflammation and iron homeostasis. The observed effects on protein misfolding, cytokine signaling, and hormones were corroborated by western blot (accumulation of polyubiquitinated proteins) or qPCR analysis. Overall, the results of the present study revealed extensive and material-specific interference of CuO and PS NPs with placental gene expression from a single short-term exposure which deserves increasing attention. In addition, the placenta, which is often neglected in developmental toxicity studies, should be a key focus in the future safety assessment of NPs in pregnancy.

Urinary copper levels are associated with bronchiectasis in non-smokers living near a petrochemical complex

The incidence of respiratory diseases has been associated with copper in particulate matter; however, the relationship between urinary copper levels and interstitial lung changes remains unclear. Therefore, we conducted a population-based study in southern Taiwan between 2016 and 2018, excluding individuals with a history of lung carcinoma, pneumonia, and cigarette smoking. Low-dose computed tomography (LDCT) was performed to detect lung interstitial changes, including the presence of ground-glass opacity or bronchiectasis in LDCT images. We categorized urinary copper levels into quartiles (Q1: ≤10.3; Q2: >10.4 and ≤14.2; Q3: >14.3 and ≤18.9; and Q4: >19.0 μg/L) and analyzed the risk of interstitial lung changes using multiple logistic regression analysis. The urinary copper levels were significantly positively correlated with age, body mass index, serum white blood cell count, aspartate aminotransferase, alanine aminotransferase, creatinine, triglycerides, fasting glucose, and glycated hemoglobin and significantly negatively correlated with platelet count and high-density lipoprotein cholesterol. The study found that the highest quartile of urinary copper levels (Q4) was significantly associated with an increased risk of bronchiectasis compared to the lowest quartile (Q1) of urinary copper levels, with an odds ratio (OR) of 3.49 and a 95% confidence interval (CI) of 1.12-10.88. However, the association between urinary copper levels and interstitial lung disease needs further investigation in future studies.

MMP-3-mediated cleavage of OPN is involved in copper oxide nanoparticle-induced activation of fibroblasts

BACKGROUND

Copper oxide nanoparticles (Nano-CuO) are one of the most produced and used nanomaterials. Previous studies have shown that exposure to Nano-CuO caused acute lung injury, inflammation, and fibrosis. However, the mechanisms underlying Nano-CuO-induced lung fibrosis are still unclear. Here, we hypothesized that exposure of human lung epithelial cells and macrophages to Nano-CuO would upregulate MMP-3, which cleaved osteopontin (OPN), resulting in fibroblast activation and lung fibrosis.

METHODS

A triple co-culture model was established to explore the mechanisms underlying Nano-CuO-induced fibroblast activation. Cytotoxicity of Nano-CuO on BEAS-2B, U937* macrophages, and MRC-5 fibroblasts were determined by alamarBlue and MTS assays. The expression or activity of MMP-3, OPN, and fibrosis-associated proteins was determined by Western blot or zymography assay. Migration of MRC-5 fibroblasts was evaluated by wound healing assay. MMP-3 siRNA and an RGD-containing peptide, GRGDSP, were used to explore the role of MMP-3 and cleaved OPN in fibroblast activation.

RESULTS

Exposure to non-cytotoxic doses of Nano-CuO (0.5 and 1 µg/mL) caused increased expression and activity of MMP-3 in the conditioned media of BEAS-2B and U937* cells, but not MRC-5 fibroblasts. Nano-CuO exposure also caused increased production of cleaved OPN fragments, which was abolished by MMP-3 siRNA transfection. Conditioned media from Nano-CuO-exposed BEAS-2B, U937*, or the co-culture of BEAS-2B and U937* caused activation of unexposed MRC-5 fibroblasts. However, direct exposure of MRC-5 fibroblasts to Nano-CuO did not induce their activation. In a triple co-culture system, exposure of BEAS-2B and U937* cells to Nano-CuO caused activation of unexposed MRC-5 fibroblasts, while transfection of MMP-3 siRNA in BEAS-2B and U937* cells significantly inhibited the activation and migration of MRC-5 fibroblasts. In addition, pretreatment with GRGDSP peptide inhibited Nano-CuO-induced activation and migration of MRC-5 fibroblasts in the triple co-culture system.

CONCLUSIONS

Our results demonstrated that Nano-CuO exposure caused increased production of MMP-3 from lung epithelial BEAS-2B cells and U937* macrophages, which cleaved OPN, resulting in the activation of lung fibroblasts MRC-5. These results suggest that MMP-3-cleaved OPN may play a key role in Nano-CuO-induced activation of lung fibroblasts. More investigations are needed to confirm whether these effects are due to the nanoparticles themselves and/or Cu ions.

Comparative Evaluation of the Cytotoxic Effects of Metal Oxide and Metalloid Oxide Nanoparticles: An Experimental Study

Industrial production generates aerosols of complex composition, including an ultrafine fraction. This is typical for mining and metallurgical industries, welding processes, and the production and recycling of electronics, batteries, etc. Since nano-sized particles are the most dangerous component of inhaled air, in this study we aimed to establish the impact of the chemical nature and dose of nanoparticles on their cytotoxicity. Suspensions of CuO, PbO, CdO, Fe₂O₃, NiO, SiO₂, Mn₃O₄, and SeO nanoparticles were obtained by laser ablation. The experiments were conducted on outbred female albino rats. We carried out four series of a single intratracheal instillation of nanoparticles of different chemical natures at doses ranging from 0.2 to 0.5 mg per animal. Bronchoalveolar lavage was taken 24 h after the injection to assess its cytological and biochemical parameters. At a dose of 0.5 mg per animal, cytotoxicity in the series of nanoparticles changed as follows (in decreasing order): CuO NPs > PbO NPs > CdO NPs > NiO NPs > SiO₂ NPs > Fe₂O₃ NPs. At a lower dose of 0.25 mg per animal, we observed a different pattern of cytotoxicity of the element oxides under study: NiO NPs > Mn₃O₄ NPs > CuO NPs > SeO NPs. We established that the cytotoxicity increased non-linearly with the increase in the dose of nanoparticles of the same chemical element (from 0 to 0.5 mg per animal). An increase in the levels of intracellular enzymes (amylase, AST, ALT, LDH) in the supernatant of the bronchoalveolar lavage fluid indicated a cytotoxic effect of nanoparticles. Thus, alterations in the cytological parameters of the bronchoalveolar lavage and the biochemical characteristics of the supernatant can be used to predict the danger of new nanomaterials based on their comparative assessment with the available tested samples of nanoparticles.

Early events marking lung fibroblast transition to profibrotic state in idiopathic pulmonary fibrosis

BACKGROUND

Idiopathic Pulmonary Fibrosis (IPF) is an age-associated progressive lung disease with accumulation of scar tissue impairing gas exchange. Previous high-throughput studies elucidated the role of cellular heterogeneity and molecular pathways in advanced disease. However, critical pathogenic pathways occurring in the transition of fibroblasts from normal to profibrotic have been largely overlooked.

METHODS

We used single cell transcriptomics (scRNA-seq) from lungs of healthy controls and IPF patients (lower and upper lobes). We identified fibroblast subclusters, genes and pathways associated with early disease. Immunofluorescence assays validated the role of MOXD1 early in fibrosis.

RESULTS

We identified four distinct fibroblast subgroups, including one marking the normal-to-profibrotic state transition. Our results show for the first time that global downregulation of ribosomal proteins and significant upregulation of the majority of copper-binding proteins, including MOXD1, mark the IPF transition. We find no significant differences in gene expression in IPF upper and lower lobe samples, which were selected to have low and high degree of fibrosis, respectively.

CONCLUSIONS

Early events during IPF onset in fibroblasts include dysregulation of ribosomal and copper-binding proteins. Fibroblasts in early stage IPF may have already acquired a profibrotic phenotype while hallmarks of advanced disease, including fibroblast foci and honeycomb formation, are still not evident. The new transitional fibroblasts we discover could prove very important for studying the role of fibroblast plasticity in disease progression and help develop early diagnosis tools and therapeutic interventions targeting earlier disease states.

Comparative toxicological evaluations of novel forms nano-pesticides in liver and lung of albino rats

Copper oxide Nanoparticles (CuONPs) are used in different agricultural applications. Large amounts of CuONPs cause organ dysfunction in animals. Our study aim to compare between the toxic effects of CuONanSphere (CuONSp) and CuONanoFlower (CuONF) as new nano-pesticides, determine a less toxic form when used in agricultural applications. To characterize CuONSp and CuONF, we used X-ray diffraction (XRD), Field emission scanning electron microscopy (SEM), and High resolution transmission electron microscopy (HRTEM) and Zeta-sizer device.18 adult male albino rats were divided into three groups (n = 6), (I) control group, (II) and (III) groups were given orally 50 mg/kg/day of CuONSp and CuONF 30 days respectively. CuONSp induced oxidant-antioxidant abnormalities, including an increase in malondialdhyde (MDA) and a decrease in glutathione (GSH) in comparison to CuONF-treated one. CuONSp induced an increase in liver enzymes activities compared to CuONF. Tumour necrosis factor-alfa (TNF-α) detected an increased in liver and lung compared to CuONF. However, histological examinations revealed changes in CuONSp group than CuONF group. Changes in immune-expressions of TNF-α, nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kβ) and tumour suppressor gene (p53) were also more identified in CuONSp group than CuONF group. Ultrastructural studies of liver and lung tissues marked alternations were observed in CuONSp group than CuONF group. In conclusion, CuONSp induced biological alternation in liver and lung more than CuONF. So, CuONF is less toxic compared to CuONSp when used as nano-pesticide in agricultural applications.

Adverse pulmonary effects after oral exposure to copper, manganese and mercury, alone and in mixtures, in a Spraque-Dawley rat model

The rise in respiratory disease has been attributed to an increase in environmental pollution. Heavy metals contribute to environmental contamination via air, water, soil and food. The effects of atmospheric exposure to heavy metals on pulmonary structure and function have been researched, but the effects through drinking water have been neglected. The aim of this study was to investigate the potential in vivo alterations in the pulmonary tissue of male Sprague-Dawley rats after a 28-day oral exposure to copper (Cu), manganese (Mn) and mercury (Hg), alone and in mixtures, at 100 times the World Health Organization's (WHO) safety limit for each heavy metal in drinking water. Forty-eight male Sprague-Dawley rats were randomly divided into eight groups (n = 6): control, Cu, Mn, Hg, Cu + Mn, Cu + Hg, Mn + Hg and Cu, Mn + Hg. The morphology of lung tissue and the bronchioles were evaluated using light- and transmission electron microscopy. For all exposed groups, morphological changes included thickened inter- and intra-alveolar spaces, stratified epithelium, disrupted smooth muscle and early fibrosis and desquamation of the epithelia of the bronchioles to varying degrees. In all exposed groups, ultrastructurally, an increase in disarranged collagen and elastin fibers, nuclear membrane detachment, chromatin condensation, indistinct nucleoli and an increase in collagen fiber disarrangement was observed. This study has identified that oral exposure to Cu, Mn and Hg and as part of mixtures caused pathogenesis due to inflammation, cellular damage and fibrosis with Mn + Hg being the most potent heavy metal group.

Copper Exposure Induces Epithelial-Mesenchymal Transition-Related Fibrotic Change via Autophagy and Increase Risk of Lung Fibrosis in Human

Copper is an essential trace element involved in several vital biological processes of the human body. However, excess exposure to copper caused by occupational hazards and environmental contamination, such as food, water, and air, damages human health. In this study, in vitro cell culture model and epidemiologic studies were conducted to evaluate the effect of copper on lung fibrosis. In vitro, treatment of CuSO₄ in lung epithelial cells at 100 μM consistently decreases cell viability in alveolar type (A549) and human bronchial epithelial (HBE) cells. CuSO₄ promotes epithelial-mesenchymal transition (EMT) as shown by increased cell migration and increased EMT marker and fibrotic gene expressions. Besides, CuSO₄ induced cell autophagy, with an increased LC3, PINK, and decreased p62 expression. Inhibition of ROS by N-acetylcysteine reversed the CuSO₄-induced PINK1, LC3, and Snail expressions. Inhibition of autophagy by chloroquine reverses the CuSO₄-induced EMT changes. Nature flavonoids, especially kaempferol, and fustin, were shown to inhibit Copper-induced EMT. In humans, a unit increase in urinary copper concentration was significantly associated with an increased risk of lung fibrotic changes (odds ratio [OR] = 1.17, 95% confidence interval [CI] = 1.01-1.36, p = 0.038). These results indicated that Copper is a risk factor for lung fibrosis through activation of the ROS-autophagy-EMT pathway, which can be reversed by flavonoids.

Melatonin ameliorates chronic copper-induced lung injury

Copper (Cu) is an important trace element required for several biological processes. The use of copper is increasing gradually in several applications. Previous studies suggest that excess levels of copper are attributed to induce oxidative stress and inflammation, mediating tissue damage. Inline, melatonin the hormone of darkness has been reported to exhibit various therapeutic effects including strong free radical scavenging properties and anti-inflammatory effects. However, its effects against pulmonary injury promoted by copper are not explored and remain unclear so far. Therefore, the present study was aimed to investigate the protective effect of melatonin against copper-induced lung damage. Female Sprague Dawley (SD) rats were exposed to 250 ppm of copper in drinking water for 16 weeks and treated with melatonin (i.p.) 5 and 10 mg/kg from the week (13-16th). The extent of tissue damage was assessed by tissue oxidative stress parameters, metal estimation and histological analysis. Copper-challenged rats showed altered oxidative stress variables. In addition, metal analysis revealed increased copper accumulation in the lungs and histological staining results further indicated severe tissue injury and inflammatory cell infiltration in copper-exposed rats. To this side, treatment with melatonin showed antioxidant and anti-inflammatory activities evidenced by reduced oxidative stress, tissue inflammation and collagen deposition as compared to copper-exposed animals. Moreover, spectral findings suggested melatonin treatment modulated the frequency sift, as compared to copper-challenged animals. Altogether, the present results suggest that melatonin might play a potential role in preventing copper-induced lung aberrations via inhibiting the ROS-mediated oxidative stress and inflammation.

A Nanomedicine Structure-Activity Framework for Research, Development, and Regulation of Future Cancer Therapies

Despite their clinical success in drug delivery applications, the potential of theranostic nanomedicines is hampered by mechanistic uncertainty and a lack of science-informed regulatory guidance. Both the therapeutic efficacy and the toxicity of nanoformulations are tightly controlled by the complex interplay of the nanoparticle's physicochemical properties and the individual patient/tumor biology; however, it can be difficult to correlate such information with observed outcomes. Additionally, as nanomedicine research attempts to gradually move away from large-scale animal testing, the need for computer-assisted solutions for evaluation will increase. Such models will depend on a clear understanding of structure-activity relationships. This review provides a comprehensive overview of the field of cancer nanomedicine and provides a knowledge framework and foundational interaction maps that can facilitate future research, assessments, and regulation. By forming three complementary maps profiling nanobio interactions and pathways at different levels of biological complexity, a clear picture of a nanoparticle's journey through the body and the therapeutic and adverse consequences of each potential interaction are presented.

Antimicrobial Properties of CuO Particles Deposited on a Medical Mask

Medical face masks help to reduce the transmission of pathogens, however, the number of infections caused by antimicrobial-resistant pathogens continues to increase. The aim of this study was to investigate the antimicrobial effect of an experimental medical mask layer coated with copper oxide using an environmentally friendly non-thermal physical vapour deposition approach. Pure CuO nanoparticles were successfully deposited on the middle layer of a face mask. The particles were distributed in different size clusters (starting from less than 100 nm dots going up to about 1 µm cluster-like structures). The CuO clusters did not form uniform films, which could negatively influence airflow during use of the mask. We investigated the antimicrobial properties of the experimental mask layer coated with CuO NPs using 17 clinical and zoonotic strains of gram-negative, gram-positive, spore-forming bacteria and yeasts, during direct and indirect contact with the mask surface. The effectiveness of the coated mask layer depended on the deposition duration of CuO. The optimal time for deposition was 30 min, which ensured a bactericidal effect for both gram-positive and gram-negative bacteria, including antimicrobial-resistant strains, using 150 W power. The CuO NPs had little or no effect on Candida spp. yeasts.

Pulmonary Toxicity and Proteomic Analysis in Bronchoalveolar Lavage Fluids and Lungs of Rats Exposed to Copper Oxide Nanoparticles

Copper oxide nanoparticles (CuO NPs) were intratracheally instilled into lungs at concentrations of 0, 0.15, and 1.5 mg/kg bodyweight to 7-week-old Sprague-Dawley rats. The cytotoxicity, immunotoxicity, and oxidative stress were evaluated, followed by proteomic analysis of bronchoalveolar lavage fluid (BALF) and lungs of rats. The CuO NPs-exposed groups revealed dose-dependent increases in total cells, polymorphonuclear leukocytes, lactate dyhydrogenase, and total protein levels in BALF. Inflammatory cytokines, including macrophage inflammatory protein-2 and tumor necrosis factor-α, were increased in the CuO NPs-treated groups. The expression levels of catalase, glutathione peroxidase-1, and peroxiredoxin-2 were downregulated, whereas that of superoxide dismutase-2 was upregulated in the CuO NPs-exposed groups. Five heat shock proteins were downregulated in rats exposed to high concentrations of CuO NPs. In proteomic analysis, 17 proteins were upregulated or downregulated, and 6 proteins were validated via Western blot analysis. Significant upregulation of 3-hydroxy-3-methylglutaryl-CoA synthase and fidgetin-like 1 and downregulation of annexin II, HSP 47 and proteasome α1 occurred in the CuO NPs exposed groups. Taken together, this study provides additional insight into pulmonary cytotoxicity and immunotoxicity as well as oxidative stress in rats exposed to CuO NPs. Proteomic analysis revealed potential toxicological biomarkers of CuO NPs, which also reveals the toxicity mechanisms of CuO NPs.

Exploring the Potential of Metal Nanoparticles as a Possible Therapeutic Adjunct for Covid-19 Infection

The WHO has declared the Covid-19 outbreak as a global health emergency with a mortality rate of approximately 3%, across 200 countries. There has been a considerable risk involved with drug repurposing in Covid-19 treatment, particularly in patients with underlying chronic disorders. Intervention of appropriate adjunct to primary drug therapy at subclinical or clinical doses may help to reduce unintended consequences involved in Covid-19 therapy. Metal nanoparticles due to their intrinsic structural and functional properties, not only contribute to anti-viral properties but also help to reduce the risk for associated complications. Although, silver nanoparticles hold great promise as an effective biocidal agent, while other metal nanoparticles also fueled interest against virus infection. The present review discusses the important properties of selected metal nanoparticles, their antiviral principle with possible toxic consequences, provides invaluable information for scientists and clinicians about an appropriate metal nanoparticle as an adjunct for Covid-19 treatment.

Effective antiviral coatings for deactivating SARS-CoV-2 virus on N95 respirator masks or filters

The application of antiviral coatings to masks and respirators is a potential mitigating step toward reducing viral transmission during the SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) pandemic. The use of appropriate masks, social distancing, and vaccines is the immediate solution for limiting the viral spread and protecting people from this virus. N95 respirator masks are effective in filtering the virus particles, but they cannot kill or deactivate the virus. We report a possible approach to deactivating SARS-CoV-2 by applying an antimicrobial coating (Goldshield 75) to masks and respirators, rendering them suitable for repeated use. Masks coated with Goldshield 75 demonstrated continuous inactivation of the Alpha and Beta variants of the SARS-CoV-2 over a 3-day period and no loss of inactivation when stored at temperatures at 50 °C.

Copper Oxide Nanoparticles Stimulate the Immune Response and Decrease Antioxidant Defense in Mice After Six-Week Inhalation

Copper oxide nanoparticles (CuO NPs) are increasingly used in various industry sectors. Moreover, medical application of CuO NPs as antimicrobials also contributes to human exposure. Their toxicity, including toxicity to the immune system and blood, raises concerns, while information on their immunotoxicity is still very limited. The aim of our work was to evaluate the effects of CuO NPs (number concentration 1.40×106 particles/cm3, geometric mean diameter 20.4 nm) on immune/inflammatory response and antioxidant defense in mice exposed to 32.5 µg CuO/m3 continuously for 6 weeks. After six weeks of CuO NP inhalation, the content of copper in lungs and liver was significantly increased, while in kidneys, spleen, brain, and blood it was similar in exposed and control mice. Inhalation of CuO NPs caused a significant increase in proliferative response of T-lymphocytes after mitogenic stimulation and basal proliferative activity of splenocytes. CuO NPs significantly induced the production of IL-12p70, Th1-cytokine IFN-γ and Th2-cytokines IL-4, IL-5. Levels of TNF-α and IL-6 remained unchanged. Immune assays showed significantly suppressed phagocytic activity of granulocytes and slightly decreased respiratory burst. No significant differences in phagocytosis of monocytes were recorded. The percentage of CD3+, CD3+CD4+, CD3+CD8+, and CD3-CD19+ cell subsets in spleen, thymus, and lymph nodes did not differ between exposed and control animals. No changes in hematological parameters were found between the CuO NP exposed and control groups. The overall antioxidant protection status of the organism was expressed by evaluation of GSH and GSSG concentrations in blood samples. The experimental group exposed to CuO NPs showed a significant decrease in GSH concentration in comparison to the control group. In summary, our results indicate that sub-chronic inhalation of CuO NPs can cause undesired modulation of the immune response. Stimulation of adaptive immunity was indicated by activation of proliferation and secretion functions of lymphocytes. CuO NPs elicited pro-activation state of Th1 and Th2 lymphocytes in exposed mice. Innate immunity was affected by impaired phagocytic activity of granulocytes. Reduced glutathione was significantly decreased in mice exposed to CuO NPs.

The effect of nanoparticles on pulmonary fibrosis: a systematic review and Meta-analysis of preclinical studies

Air pollution is a big ecumenical problem associated with public health around the world. The rapid development of nanotechnology worldwide resulted in a significant increase in human exposure with unknown particles, and ultimately leading to an increase in acute and chronic diseases. The effect of nanoparticles on pulmonary fibrosis has been reported in vivo and in vitro studies; however, the results are inconsistent. The present systematic review and meta-analysis of animal preclinical studies was conducted to assess the effect of nanoparticles on pulmonary fibrosis. A systematic search of online databases and gray literature as well as reference lists of retrieved studies was performed up to February 2019 to identify preclinical animal studies. Studies were assessed for methodological quality using the SYstematic Review Center for Laboratory animal Experimentation bias risk tool (SYRCLE's ROB tool). Pooled standardized mean difference (SMD) estimate with corresponding 95% CI was calculated using inverse-variance weights method while random effects meta-analysis was used, taking into account conceptual heterogeneity. To assess the robustness of pooled estimates as well as heterogeneity across studies, sensitivity analysis and Cochran Q statistic (with I² statistic) was carried out using Stata 11.0. Of 6494 retrieved studies, 85 were reviewed in depth for eligibility. 16 studies met the criteria for inclusion in this systematic review. The meta-analysis was conducted on 10 studies which had reported the mean of TGF-β in 7 days after exposure by nanoparticles jointly (exposure compared to no exposure). Findings showed that exposure to nanoparticles significantly induced pulmonary fibrosis (SMD: 4.12, 95% CI: 2.57-5.67). A statistical heterogeneity was found [P < 0.001 (Q statistics), I² = 83.0%] across studies. Nanoparticles were the most influencing in inducing pulmonary fibrosis in animal models. Sensitivity analysis demonstrated consistency of the results, indicating that the meta-analysis model was robust. Publication bias (using visual inspection and statistical tests) was unlikely in the association between nanoparticles and pulmonary fibrosis. We found that the nanoparticles significantly induce pulmonary fibrosis through increasing proinflammatory cytokine TGF-β and histopathological changes.

Copper Oxide Nanoparticles Stimulate the Immune Response and Decrease Antioxidant Defense in Mice After Six-Week Inhalation

Copper oxide nanoparticles (CuO NPs) are increasingly used in various industry sectors. Moreover, medical application of CuO NPs as antimicrobials also contributes to human exposure. Their toxicity, including toxicity to the immune system and blood, raises concerns, while information on their immunotoxicity is still very limited. The aim of our work was to evaluate the effects of CuO NPs (number concentration 1.40×10⁶ particles/cm³, geometric mean diameter 20.4 nm) on immune/inflammatory response and antioxidant defense in mice exposed to 32.5 µg CuO/m³ continuously for 6 weeks. After six weeks of CuO NP inhalation, the content of copper in lungs and liver was significantly increased, while in kidneys, spleen, brain, and blood it was similar in exposed and control mice. Inhalation of CuO NPs caused a significant increase in proliferative response of T-lymphocytes after mitogenic stimulation and basal proliferative activity of splenocytes. CuO NPs significantly induced the production of IL-12p70, Th1-cytokine IFN-γ and Th2-cytokines IL-4, IL-5. Levels of TNF-α and IL-6 remained unchanged. Immune assays showed significantly suppressed phagocytic activity of granulocytes and slightly decreased respiratory burst. No significant differences in phagocytosis of monocytes were recorded. The percentage of CD3⁺, CD3⁺CD4⁺, CD3⁺CD8⁺, and CD3^-CD19⁺ cell subsets in spleen, thymus, and lymph nodes did not differ between exposed and control animals. No changes in hematological parameters were found between the CuO NP exposed and control groups. The overall antioxidant protection status of the organism was expressed by evaluation of GSH and GSSG concentrations in blood samples. The experimental group exposed to CuO NPs showed a significant decrease in GSH concentration in comparison to the control group. In summary, our results indicate that sub-chronic inhalation of CuO NPs can cause undesired modulation of the immune response. Stimulation of adaptive immunity was indicated by activation of proliferation and secretion functions of lymphocytes. CuO NPs elicited pro-activation state of Th1 and Th2 lymphocytes in exposed mice. Innate immunity was affected by impaired phagocytic activity of granulocytes. Reduced glutathione was significantly decreased in mice exposed to CuO NPs.

Lung toxicity profile of inhaled copper-nickel welding fume in A/J mice

Objective: Stainless steel welding creates fumes rich in carcinogenic metals such as chromium (Cr). Welding consumables devoid of Cr are being produced in an attempt to limit worker exposures to toxic and carcinogenic metals. The study objective was to characterize a copper-nickel (Cu-Ni) fume generated using gas metal arc welding (GMAW) and determine the pulmonary deposition and toxicity of the fume in mice exposed by inhalation. Materials and Methods: Male A/J mice (6-8 weeks of age) were exposed to air or Cu-Ni welding fumes for 2 (low deposition) or 4 (high deposition) hours/day for 10 days. Mice were sacrificed, and bronchoalveolar lavage (BAL), macrophage function, and histopathological analyses were performed at different timepoints post-exposure to evaluate resolution. Results and Discussion: Characterization of the fume indicated that most of the particles were between 0.1 and 1 µm in diameter, with a mass median aerodynamic diameter of 0.43 µm. Metal content of the fume was Cu (∼76%) and Ni (∼12%). Post-exposure, BAL macrophages had a reduced ability to phagocytose E. coli, and lung cytotoxicity was evident and significant (>12%-19% fold change). Loss of body weight was also significant at the early timepoints. Lung inflammation, the predominant finding identified by histopathology, was observed as a subacute response early that progressively resolved by 28 days with only macrophage aggregates remaining late (84 days). Conclusions: Overall, there was high acute lung toxicity with a resolution of the response in mice which suggests that the Cu-Ni fume may not be ideal for reducing toxic and inflammatory lung effects.

Genotoxicity of aluminium oxide, iron oxide, and copper nanoparticles in mouse bone marrow cells

The aim of this study was to evaluate the genotoxic effects of Al₂O₃, Fe₂O₃, and Cu nanoparticles with chromosomal aberration (CA), micronucleus (MN), and comet assays on the bone marrow of male BALB/c mice. Three doses of Al₂O₃, Fe₂O₃ (75, 150, and 300 mg/kg), or Cu (5, 10, and 15 mg/kg) nanoparticles were administered to mice through intraperitoneal injection once a day for 14 days and compared with negative control (distilled water) and positive control (mitomycin C and methyl methanesulphonate). Al₂O₃ and Fe₂O₃ did not show genotoxic effects, but Cu nanoparticles induced significant (P<0.05) genotoxicity at the highest concentration compared to negative control. Our findings add to the health risk information of Al₂O₃, Fe₂O₃, and Cu nanoparticles regarding human exposure (occupational and/or through consumer products or medical treatment), and may provide regulatory reference for safe use of these nanoparticles. However, before they can be used safely and released into the environment further chronic in vivo studies are essential.

Mixed Pneumoconiosis Associated with Diffuse Pulmonary Ossification in Wild Coyotes (Canis latrans)

Mixed pneumoconiosis is a pulmonary disease associated with several inhaled mineral irritants. Dust was found in the alveolar macrophages, alveolar and bronchial walls and pulmonary interstitial tissue of two female coyotes (Canis latrans). The dust contained large amounts of silica, coal, iron and copper particles, which were associated with severe pulmonary disease. Lung injury in the animals was characterized by pulmonary nodules, severe interstitial fibrosis, alveolar hyperplasia and bone formation within alveolar spaces. Coyotes inhaled mineral dust while roaming a field close to three mineral extraction zones. To our knowledge, this is the first report of the concomitant inhalation of multiple minerals in association with diffuse pulmonary ossification in the pulmonary parenchyma of two wild canine animals.

MMP-3 activation is involved in copper oxide nanoparticle-induced epithelial-mesenchymal transition in human lung epithelial cells

Copper oxide nanoparticles (Nano-CuO) are widely used in medical and industrial fields and our daily necessities. However, the biosafety assessment of Nano-CuO is far behind their rapid development. Here, we investigated the adverse effects of Nano-CuO on normal human bronchial epithelial BEAS-2B cells, especially determined whether Nano-CuO exposure would cause dysregulation of MMP-3, an important mediator in pulmonary fibrosis, and its potential role in epithelial-mesenchymal transition (EMT). Our results showed that exposure to Nano-CuO, but not Nano-TiO₂, caused increased ROS generation, MAPKs activation, and MMP-3 upregulation. Nano-CuO-induced ROS generation was not observed in mitochondrial DNA-depleted BEAS-2B ρ⁰ cells, indicating that mitochondria may be the main source of Nano-CuO-induced ROS generation. Pretreatment of the cells with ROS scavengers or inhibitors or depleting mitochondrial DNA significantly attenuated Nano-CuO-induced MAPKs activation and MMP-3 upregulation, and pretreatment of cells with MAPKs inhibitors abolished Nano-CuO-induced MMP-3 upregulation, suggesting Nano-CuO-induced MMP-3 upregulation is through Nano-CuO-induced ROS generation and MAPKs activation. In addition, exposure of the cells to Nano-CuO for 48 h resulted in decreased E-cadherin expression and increased expression of vimentin, α-SMA, and fibronectin, which was ameliorated by MMP-3 siRNA transfection, suggesting an important role of MMP-3 in Nano-CuO-induced EMT. Taken together, our study demonstrated that Nano-CuO exposure caused mitochondrial ROS generation, MAPKs activation, and MMP-3 upregulation. Nano-CuO exposure also caused cells to undergo EMT, which was through Nano-CuO-induced dysregulation of ROS/MAPKs/MMP-3 pathway. Our findings will provide further understanding of the potential mechanisms involved in metal nanoparticle-induced various toxic effects including EMT and pulmonary fibrosis.

Metal Oxide Engineered Nanomaterials Modulate Rabbit Corneal Fibroblast to Myofibroblast Transformation

Purpose

Corneal keratocyte-fibroblast-myofibroblast (KFM) transformation plays a critical role in corneal stromal wound healing. However, the impact of engineered nanomaterials (ENMs), found in an increasing number of commercial products, on this process is poorly studied. This study investigates the effects of metal oxide ENMs on KFM transformation in vitro and in vivo.

Methods

Cell viability of rabbit corneal fibroblasts (RCFs) was tested following treatment with 11 metal oxide ENMs at concentrations of 0.5 to 250 µg/ml for 24 hours. Messenger RNA (mRNA) and protein expression of αSMA, a marker of myofibroblast transformation, were measured using RCFs after exposure to 11 metal oxide ENMs at a concentration that did not affect cell viability, in media containing either 0 or 10 ng/ml of TGF-β1. Additionally, the effect of topical Fe₂O₃ nanoparticles (NPs) (50 ng/ml) on corneal stromal wound healing following phototherapeutic keratectomy (PTK) was determined.

Results

V₂O₅, Fe₂O₃, CuO, and ZnO ENMs were found to significantly reduce cell viability as compared to vehicle control and the other seven metal oxide ENMs tested. V₂O₅ nanoflakes significantly reduced mRNA and protein αSMA concentrations in the presence of TGF-β1. Fe₂O₃ NPs significantly increased αSMA mRNA expression in the presence of TGF-β1 but did not alter αSMA protein expression. Topically applied Fe₂O₃ NPs in an in vivo rabbit corneal stromal wound healing model did not delay healing.

Conclusions

Fe₂O₃ NPs promote corneal myofibroblast induction in vitro but do not impair corneal stromal wound healing in vivo.

Translational Relevance

These experimental results can apply to human nanomedical research.

Copper Oxide Nanoparticle-Induced Acute Inflammatory Response and Injury in Murine Lung Is Ameliorated by Synthetic Secoisolariciresinol Diglucoside (LGM2605)

Metal-oxide nanoparticles (MO-NPs), such as the highly bioreactive copper-based nanoparticles (CuO-NPs), are widely used in manufacturing of hundreds of commercial products. Epidemiological studies correlated levels of nanoparticles in ambient air with a significant increase in lung disease. CuO-NPs, specifically, were among the most potent in a set of metal-oxides and carbons studied in parallel regarding DNA damage and cytotoxicity. Despite advances in nanotoxicology research and the characterization of their toxicity, the exact mechanism(s) of toxicity are yet to be defined. We identified chlorination toxicity as a damaging consequence of inflammation and myeloperoxidase (MPO) activation, resulting in macromolecular damage and cell damage/death. We hypothesized that the inhalation of CuO-NPs elicits an inflammatory response resulting in chlorination damage in cells and lung tissues. We further tested the protective action of LGM2605, a synthetic small molecule with known scavenging properties for reactive oxygen species (ROS), but most importantly, for active chlorine species (ACS) and an inhibitor of MPO. CuO-NPs (15 µg/bolus) were instilled intranasally in mice and the kinetics of the inflammatory response in lungs was evaluated 1, 3, and 7 days later. Evaluation of the protective action of LGM2605 was performed at 24 h post-challenge, which was selected as the peak acute inflammatory response to CuO-NP. LGM2605 was given daily via gavage to mice starting 2 days prior to the time of the insult (100 mg/kg). CuO-NPs induced a significant inflammatory influx, inflammasome-relevant cytokine release, and chlorination damage in mouse lungs, which was mitigated by the action of LGM2605. Preventive action of LGM2605 ameliorated the adverse effects of CuO-NP in lung.

A semi-quantitative risk ranking of potential human exposure to engineered nanoparticles (ENPs) in Europe

Large quantities of engineered nanoparticles (ENPs) have emerged on the European market with the rapid development of nanotechnology, however knowledge of potential health risks to humans remains in its infancy. The ENP safety issue is of pressing concern as their novel physicochemical characteristics have been illustrated compared to other bulk-form counterparts. Therefore, it is critical to carry out a comprehensive risk assessment for ENPs to guide risk management in industrial sectors. Based on current data availability, a risk ranking model is developed in accordance with the European Chemicals Agency (ECHA) advice for ENP risk assessment. In this study a Quantity, Exposure, Hazard (QEH) risk scoring model was adopted for characterizing both quantitative and qualitative data, including potential exposure pathways and hazard information. Scores were assigned to quantities of ENPs used in consumer products, intake likelihoods (oral, inhalation, and dermal intake), and hazard potential. Exposure through environmental routes and through consumer products are regarded as significant potential exposure routes. This model prioritized ENPs used in Europe according to human health risk potential. Nano-titanium dioxide (TiO₂) ranked the highest, resulting from exposure through consumer products. Silver nanoparticles (AgNP), as the second most critical ENP, is of most concern in terms of the risk from environmental sinks. Regarding the compartmentalization of total ENP risks to humans, the consumption of consumer products with nano-ingredients, especially nano-TiO₂, nano-silicon dioxide (SiO₂), and AgNP, constitutes the majority of the QEH risk index. The inadequacy of ENP risk management procedures is highlighted, not only during manufacturing, but also during nanomaterial waste disposal processes from marketplace through to the environment. Current risk assessments are based upon recent knowledge of the ENP class as novel pollutants, highlighting the need for further quantification of underlying risks as data emerges.

Nanotechnologies for intranasal drug delivery: an update of literature

Scientific research has focused its attention on finding an alternative route to systemic oral and parenteral administration, to overcome their usual drawbacks, such as hepatic first-pass which decreases drug bioavailability after oral administration, off-target effects, low patient compliance and low speed of onset of the pharmacological action in first-aid cases. Innovative drug delivery systems (DDS), mainly based on polymer and lipid biocompatible materials, have given a great prompt in this direction in the last years. The intranasal (IN) route of administration is a valid non-invasive alternative. It is highly suitable for self-administration, the drug quickly reaches the bloodstream, largely avoiding the first pass effect, and can also reach directly the brain bypassing BBB. Association of IN route with DDS can thus become a winning strategy for the controlled delivery of drugs, especially when a very quick effect is desired or needed. This review aims at analyzing the scientific literature regarding IN-DDS and their different ways of administration (systemic, topical, pulmonary, nose-to-brain). In particular, attention was devoted to polymer- and lipid-based micro- and nanocarriers, being the topic of most published articles in the last decade, but the whole plethora of colloidal DDS investigated in recent years for IN administration was presented.

Silver, copper and copper oxide nanoparticles in the fight against human viruses: progress and perspectives

The rapid development of nanomedicine has created a high demand for silver, copper and copper oxide nanoparticles. Due to their high reactivity and potent antimicrobial activity, silver and copper-based nanomaterials have been playing an important role in the search for new alternatives for the treatment of several issues of concern, such as pathologies caused by bacteria and viruses. Viral diseases are a significant and constant threat to public health. The most recent example is the pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). In this context, the object of the present review is to highlight recent progress in the biomedical uses of these metal nanoparticles for the treatment and prevention of human viral infections. We discuss the antiviral activity of AgNPs and Cu-based NPs, including their actions against SARS-CoV-2. We also discuss the toxicity, biodistribution and excretion of AgNPs and CuNPs, along with their uses in medical devices or on inert surfaces to avoid viral dissemination by fomites. The challenges and limitations of the biomedical use of these nanoparticles are presented.

Autophagy deficiency exacerbates acute lung injury induced by copper oxide nanoparticles

Copper oxide nanoparticles (CuONPs) are one of the widely used metal nanoparticles in the industrial and commercial fields. Autophagy is an intracellular degradation system that delivers cytoplasmic constituents to the lysosome and has been linked to nanoparticles-induced toxicity. In particular, the roles of autophagy in response to CuONPs have been explored in vitro, although the conclusions are controversial. To clarify the role of autophagy in CuONPs-induced acute lung injury, microtubule-associated protein 1 light chain 3 beta (Map1lc3b or lc3b) knockout mice and their corresponding wild type mice are applied. Our results showed that single-dose intratracheal instillation of CuONPs with dosages of 1.25, 2.5 or 5 mg/kg caused acute lung injury 3 days after treatment in a dose-dependent manner, as evidenced by deteriorative lung histopathology, more infiltration of macrophage cells, increased oxidative stress and copper ions. Loss of lc3b resulted in aggravated lung injury induced by CuONPs, which was probably due to the blockade of mitophagy and consequently the accumulation of aberrant mitochondria with overloaded copper ions. Our study provides the first in vivo evidence that autophagy deficiency exacerbates CuONPs-induced acute lung injury, and highlights that targeting autophagy is a meaningful strategy against CuONPs-associated respiratory toxicity.

Cellular Mechanisms Involved in the Combined Toxic Effects of Diesel Exhaust and Metal Oxide Nanoparticles

Diesel exhaust particles (DEPs) and non-exhaust particles from abrasion are two main representative sources of air pollution to which humans are exposed daily, together with emerging nanomaterials, whose emission is increasing considerably. In the present work, we aimed to investigate whether DEPs, metal oxide nanoparticles (MeO-NPs), and their mixtures could affect alveolar cells. The research was focused on whether NPs induced different types of death in cells, and on their effects on cell motility and migration. Autophagy and cell cycles were investigated via cytofluorimetric analyses, through the quantification of the autophagic biomarker LC3B and PI staining, respectively. Cellular ultrastructures were then observed via TEM. Changes in cell motility and migration were assessed via transwell migration assay, and by the cytofluorimetric analysis of E-cadherin expression. A colony-forming efficiency (CFE) assay was performed in order to investigate the interactions between cells inside the colonies, and to see how these interactions change after exposure to the single particles or their mixtures. The results obtained suggest that NPs can either reduce the toxicity of DEPs (CuO) or enhance it (ZnO), through a mechanism that may involve autophagy as cells' response to stressors and as a consequence of particles' cellular uptake. Moreover, NPs can induce modification of E-cadherin expression and, consequentially, of colonies' phenotypes.

TGF-β1-induced EMT activation via both Smad-dependent and MAPK signaling pathways in Cu-induced pulmonary fibrosis

Copper (Cu) is considered as an essential trace element for living organisms. However, over-exposure to Cu can lead to adverse health effects on human and animals. There are limited researches on pulmonary toxicity induced by Cu. Here, we found that copper sulfate (CuSO4)-treatment could induce pulmonary fibrosis with Masson staining and up-regulated protein and mRNA expression of Collagen I and α-Smooth Muscle Actin (α-SMA) in mice. Next, the mechanism underlying Cu-induced pulmonary fibrosis was explored, including transforming growth factor-β1 (TGF-β1)-mediated Smad pathway, mitogen-activated protein kinases (MAPKs) pathway and epithelial-mesenchymal transition (EMT). CuSO4 triggered pulmonary fibrosis by activation of the TGF-β1/Smad pathway, which was accomplished by increasing TGF-β1, p-Smad2 and p-Smad3 protein and mRNA expression levels. Also, up-regulated protein and mRNA expression of p-JNK, p-ERK, and p-p38 demonstrated that CuSO4 activated MAPKs pathways. Concurrently, EMT was activated by increasing vimentin and N-cadherin while decreasing E-cadherin protein and mRNA expression levels. Altogether, the abovementioned findings indicate that CuSO4 treatment may induce pulmonary fibrosis through the activation of EMT induced by TGF-β1/Smad pathway and MAPKs pathways, revealing the mechanism Cu-caused pulmonary toxicity.

The levels of trace elements in sputum as biomarkers for idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a rare lung disease that quickly leads to death. This paper addressed the issue of whether the levels of trace elements in sputum samples are suitable biomarkers for IPF disease. The sputum Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn concentrations were measured by sector field inductively coupled plasma mass spectrometry in populations sampled in Sardinia Island (Italy) including 31 patients with IPF, 31 patients with other lung-related diseases and 30 age- and gender-matched healthy controls. Risk factors in the disease as gender, age, severity and duration of the disease were assessed. Results showed that IPF patients had significantly increased sputum levels of Cd, Cr, Cu and Pb respect to controls. In males, but not in females, sputum levels of Cd, Cr and Cu were significantly higher in IPF cases respect to controls. In addition, Cr and Pb were increased in male patients with IPF compared to male patients with other lung diseases. Regarding Zn, it was found higher with the more serious stage of disease. Moreover, the ratios Cu/Zn, Fe/Mn and Cu/Mn were significantly increased in IPF patients and in non-IPF patients than in control subjects. These data showed clear increases in the concentration of some trace elements in sputum from patients with IPF and patients with other lung-related diseases that may contribute to the injury. The non-invasiveness of the sputum analysis is beneficial for its use as biomarker of trace element status in diseased patients for both the researcher and the clinic.

Biocompatibility of nanomaterials and their immunological properties

Nanomaterials (NMs) have revolutionized multiple aspects of medicine by enabling novel sensing, diagnostic, and therapeutic approaches. Advancements in processing and fabrication have also allowed significant expansion in the applications of the major classes of NMs based on polymer, metal/metal oxide, carbon, liposome, or multi-scale macro-nano bulk materials. Concomitantly, concerns regarding the nanotoxicity and overall biocompatibility of NMs have been raised. These involve putative negative effects on both patients and those subjected to occupational exposure during manufacturing. In this review, we describe the current state of testing of NMs including those that are in clinical use, in clinical trials, or under development. We also discuss the cellular and molecular interactions that dictate their toxicity and biocompatibility. Specifically, we focus on the reciprocal interactions between NMs and host proteins, lipids, and sugars and how these induce responses in immune and other cell types leading to topical and/or systemic effects.

Impact of copper oxide particle dissolution on lung epithelial cell toxicity: response characterization using global transcriptional analysis

The in vitro and in vivo toxicity of copper oxide nanoparticles (CuO NPs) is attributed to both particle and dissolved copper ion species. However, a clear understanding of (1) the specific cellular responses that are modulated by the two species and (2) the temporal dynamics in toxicity, as the proportional amount of particulate and ionic forms change over time, is lacking. In the current study, in vitro responses to microparticulate CuO (CuO MPs), CuO NPs, and dissolved Cu²⁺ were characterized in order to elucidate particle and ion-induced kinetic effects. Particle dissolution experiments were carried out in a relevant cell culture medium, using CuO NPs and MPs. Mouse lung epithelial cells were exposed for 2-48 h with 1-25 µg/mL CuO MPs, CuO NPs, or 7 and 54 µg/mL CuCl₂. Cellular viability and genome-wide transcriptional responses were assessed. Dose and time-dependent cytotoxicity were observed in CuO NP exposed cells, which was delayed and subtle in CuCl₂ and not observed in CuO MPs treated cells. Analyses of differentially expressed genes and associated pathway perturbations showed that dissolved ions released by CuO NPs in the extracellular medium are insufficient to account for the observed potency and cytotoxicity. Further organization of gene expression results in an Adverse Outcome Pathway (AOP) framework revealed a series of key events potentially involved in CuO NPs toxicity. The AOP is applicable to toxicity induced by metal oxide nanoparticles of varying solubility, and thus, can facilitate the development of in vitro alternative strategies to screen their toxicity.

Recent Advancement in Nanotechnology-Based Drug Delivery System Against Viral Infections

In the last few decades, the exponential rise in the incidence of viral infections sets a global health emergency across the world. The biomimetic architecture, the ability to hijack host immune responses, continuous antigen shifting, and drafting are the major critical factors that are responsible for the unavailability of a concrete therapeutic regimen against viral infections. Further, inappropriate pharmacodynamic physicochemical and biological parameters such as low aqueous solubility, poor permeability, high affinity for plasm proteins, short biological half-lives, and fast elimination from the systemic circulation are the major critical factors that govern the suboptimal drug concentration at the target site that leads to the development of drug resistance. To address this issue, nanotechnology-based drug delivery approach is emerged as an altering method to attain the optimal drug concentration at the target site for a prolonged period by integrating the nanoengineering tools in the synthesis of nanoparticles. Nanodimensional configuration with enhanced permeability and retention effect, increased surface-area-to-volume ratio, provision for surface functionalization, etc., are the privileged aspects that make it an effective drug delivery system for dispensing the antiviral therapeutics. However, size, shape, charge, and surface topology of nanoparticles are the greater influential factors that determine target-specific drug delivery, optimum cellular uptake, degree of opsonization by the host immune cells, drug retention time, transcytosis, the extension of biological half-life, in vivo stability, and cytotoxicity. The review will enlighten the elaborative role of nanotechnology-based drug delivery and the major challenging aspect of clinical safety and efficacy.

Inflammation accelerates copper-mediated cytotoxicity through induction of six-transmembrane epithelial antigens of prostate 4 expression

Copper is an essential trace metal, but imbalance in copper homeostasis can induce oxidative damage. Inflammation is a fundamental element of various pulmonary diseases. Although a positive relationship between copper and chronic pulmonary diseases has been reported, the underlying reasons are still not clear. The copper level in the sputum of patients with various pulmonary diseases was measured. An inflammatory model was established to evaluate the impact of inflammation on copper uptake in the lung. We found that the level of sputum copper was increased in patients with various pulmonary diseases, especially chronic obstructive pulmonary disease and asthma. Then, we confirmed that mice with pulmonary inflammation were susceptible to copper-mediated oxidative damage because of copper overload in lung tissue. Further investigation demonstrated that interleukin (IL)-17 and tumor necrosis factor (TNF)-α exerted synergistic effects in airway epithelial cells by upregulating the expression of six-transmembrane epithelial antigens of prostate 4 (STEAP4), a metalloreductase that reduces extracellular copper ions from the cupric state to the cuprous state and facilitates copper uptake. Inhibition of STEAP4 decreased the copper uptake of cells and inhibited copper-mediated oxidative damage. Moreover, we demonstrated that the upregulation of STEAP4 by IL-17 and TNF-α was largely dependent on TNF receptor-associated factor 4 (TRAF4). Traf4^-/- mice were resistant to copper-mediated oxidative damage. Our data suggest a novel IL-17/TNF-α-TRAF4-STEAP4 axis that regulates copper homeostasis.

A Clearance Period after Soluble Lead Nanoparticle Inhalation Did Not Ameliorate the Negative Effects on Target Tissues Due to Decreased Immune Response

The inhalation of metal (including lead) nanoparticles poses a real health issue to people and animals living in polluted and/or industrial areas. In this study, we exposed mice to lead(II) nitrate nanoparticles [Pb(NO₃)₂ NPs], which represent a highly soluble form of lead, by inhalation. We aimed to uncover the effects of their exposure on individual target organs and to reveal potential variability in the lead clearance. We examined (i) lead biodistribution in target organs using laser ablation and inductively coupled plasma mass spectrometry (LA-ICP-MS) and atomic absorption spectrometry (AAS), (ii) lead effect on histopathological changes and immune cells response in secondary target organs and (iii) the clearance ability of target organs. In the lungs and liver, Pb(NO₃)₂ NP inhalation induced serious structural changes and their damage was present even after a 5-week clearance period despite the lead having been almost completely eliminated from the tissues. The numbers of macrophages significantly decreased after 11-week Pb(NO₃)₂ NP inhalation; conversely, abundance of alpha-smooth muscle actin (α-SMA)-positive cells, which are responsible for augmented collagen production, increased in both tissues. Moreover, the expression of nuclear factor κB (NF-κB) and selected cytokines, such as tumor necrosis factor alpha (TNFα), transforming growth factor beta 1 (TGFβ1), interleukin 6(IL-6), IL-1α and IL-1β , displayed a tissue-specific response to lead exposure. In summary, diminished inflammatory response in tissues after Pb(NO₃)₂ NPs inhalation was associated with prolonged negative effect of lead on tissues, as demonstrated by sustained pathological changes in target organs, even after long clearance period.

Biomedical nanomaterials for immunological applications: ongoing research and clinical trials

Research efforts on nanomaterial-based therapies for the treatment of autoimmune diseases and cancer have spiked and have made rapid progress over the past years. Nanomedicine has been shown to contribute significantly to overcome current therapeutic limitations, exhibiting advantages compared to conventional therapeutics, such as sustained drug release, delayed drug degradation and site-specific drug delivery. Multiple nanodrugs have reached the clinic, but translation is often hampered by either low targeting efficiency or undesired side effects. Nanomaterials, and especially inorganic nanoparticles, have gained criticism due to their potential toxic effects, including immunological alterations. However, many strategies have been attempted to improve the therapeutic efficacy of nanoparticles and exploit their unique properties for the treatment of inflammation and associated diseases. In this review, we elaborate on the immunomodulatory effects of nanomaterials, with a strong focus on the underlying mechanisms that lead to these specific immune responses. Nanomaterials to be discussed include inorganic nanoparticles such as gold, silica and silver, as well as organic nanomaterials such as polymer-, dendrimer-, liposomal- and protein-based nanoparticles. Furthermore, various approaches for tuning nanomaterials in order to enhance their efficacy and attenuate their immune stimulation or suppression, with respect to the therapeutic application, are described. Additionally, we illustrate how the acquired insights have been used to design immunotherapeutic strategies for a variety of diseases. The potential of nanomedicine-based therapeutic strategies in immunotherapy is further illustrated by an up to date overview of current clinical trials. Finally, recent efforts into enhancing immunogenic cell death through the use of nanoparticles are discussed.

Effective Biocidal and Wound Healing Cogency of Biocompatible Glutathione: Citrate-Capped Copper Oxide Nanoparticles Against Multidrug-Resistant Pathogenic Enterobacteria

Multidrug-resistant (MDR) superficial bacterial infections caused by carbapenem-resistant Enterobacter sp. and Klebsiella sp. have emerged as major threats toward global health care management. In search of a novel antimicrobial, our main objectives were to explore the antimicrobial, antibiofilm, and wound healing potential of glutathione and citrate-capped copper oxide nanoparticles (CuNPs) against gram-negative MDR pathogens Klebsiella quasipneumoniae and Enterobacter sp., ensuring the lowest possible host cell nano-cytotoxicity and minimum susceptibility of the CuNPs toward oxidation. The CuNPs were found to elicit reactive oxygen species (ROS) generation within bacterial cells, inhibiting the bacterial growth and division. They contributed to the remodeling of the bacterial lipopolysaccharide, induced membrane lysis, and promoted antibiofilm activities by reduced cell-cell aggregation and matrix destabilization while displaying excellent biocompatibility against HEK-293 and HeLa cell lines. The CuNPs were also instrumental in preventing postsurgical wound infections and aiding in wound closure in the murine excisional wound model, as observed in albino Wistar rats, forcing us to believe that the CuNPs are bioactive in wound therapy. The results are encouraging and demands further experimental exploitation of the particles in treating other MDR gram-negative infections, irrespective of their resistance status.