Protein and lipid homeostasis altered in rat macrophages after exposure to metallic oxide nanoparticles

Boron Nitride Nanosheets Induce Lipid Accumulation and Autophagy in Human Alveolar Lung Epithelial Cells Cultivated at Air-Liquid Interface

Hexagonal boron nitride (hBN) is an emerging 2D material attracting significant attention due to its superior electrical, chemical, and therapeutic properties. However, inhalation toxicity mechanisms of hBN in human lung cells are poorly understood. Here, cellular interaction and effects of hBN nanosheets is investigated in alveolar epithelial cells cultured on porous inserts and exposed under air-liquid interface conditions for 24 h. hBN is taken up by the cells as determined in a label-free manner via RAMAN-confocal microscopy, ICP-MS, TEM, and SEM-EDX. No significant (p > 0.05) effects are observed on cell membrane integrity (LDH release), epithelial barrier integrity (TEER), interleukin-8 cytokine production or reactive oxygen production at tested dose ranges (1, 5, and 10 µg cm-2). However, it is observed that an enhanced accumulation of lipid granules in cells indicating the effect of hBN on lipid metabolism. In addition, it is observed that a significant (p < 0.05) and dose-dependent (5 and 10 µg cm-2) induction of autophagy in cells after exposure to hBN, potentially associated with the downstream processing and breakdown of excess lipid granules to maintain lipid homeostasis. Indeed, lysosomal co-localization of lipid granules supporting this argument is observed. Overall, the results suggest that the continuous presence of excess intracellular lipids may provoke adverse outcomes in the lungs.

Incubating Green Synthesized Iron Oxide Nanorods for Proteomics-Derived Motif Exploration: A Fusion to Deep Learning Oncogenesis

The nanotechnological arena has revolutionized the diagnostic efficacies by investigating the protein corona. This displays provoking proficiencies in determining biomarkers and diagnostic fingerprints for early detection and advanced therapeutics. The green synthesized iron oxide nanoparticles were prepared via Withania coagulans and were well characterized using UV-visible spectroscopy, X-ray diffraction analysis, Fourier transform infrared spectroscopy, and nano-LC mass spectrophotometry. Iron oxides were rod-shaped with an average size of 17.32 nm and have crystalline properties. The as-synthesized nanotool mediated firm nano biointeraction with the proteins in treatment with nine different cancers. The resultant of the proteome series was filtered oddly that highlighted the variant proteins within the differentially expressed proteins on behalf of nano-bioinformatics. Further magnification focused on S13_N, RS15, RAB, and 14_3_3 domains and few abundant motifs that aid scanning biomarkers. The entire set of variant proteins contracting to common proteins elucidates the underlining mechanical proteins that are marginally assessed using the robotic nanotechnology. Additionally, the iron rods indirectly possess a prognostic effect in manipulating expression of proteins through a smarter route. Thereby, such biologically designed nanotools provide a dual approach for medical studies.

In Vitro Molecular Study of Titanium-Niobium Alloy Biocompatibility

Titanium dental implants have common clinical applications due to their biocompatibility, biophysical and biochemical characteristics. Although current titanium is thought to be safe and beneficial for patients, there are several indications that it may release toxic metal ions or metal nanoparticles from its alloys into the surrounding environment, which could lead to clinically relevant complications including toxic reactions as well as immune dysfunctions. Hence, an adequate selection and testing of medical biomaterial with outstanding properties are warranted. This study was designed to explore the biocompatibility of smooth titanium-niobium alloy (S_TiNb) versus smooth titanium commercially pure (S_TiCp)—a reference in implantology. All experiments were performed in vitro using human osteoblast-like SaOs-2 and monocyte THP-1 cell lines as models. Cell adhesion and growth morphology were determined by scanning electron microscopy, while cell viability was evaluated using WST-1 assay. Because niobate anions or niobium nanoparticles can be released from implants during biomaterial-cell interaction, potential immunotoxicity of potassium niobate (KNbO₃₎ salt was evaluated by examining both metabolic activity and transcriptomic profiling of treated THP-1 monocytes. The main findings of this study are that S_TiCp and S_TiNb discs do not show an impact on the proliferation and viability of SaOs-2 cells compared to polystyrene surfaces, whereas a significant decrease in THP-1 cells’ viability and metabolic activity was observed in the presence of S_TiNb discs compared to the control group. However, no significant changes were found neither at the metabolic activity nor at the transcriptomic level of THP-1 monocytes exposed to KNbO₃ salt, suggesting that niobium has no effect on the immune system. Overall, these data imply a possible toxicity of S_TiNb discs toward THP-1 cells, which may not be directly related to niobium but perhaps to the manufacturing process of titanium-niobium alloy. Thus, this limitation must be overcome to make titanium alloy an excellent material for medical applications.

Nanoparticle Effects on Stress Response Pathways and Nanoparticle-Protein Interactions

Nanoparticles (NPs) are increasingly used in a wide variety of applications and products; however, NPs may affect stress response pathways and interact with proteins in biological systems. This review article will provide an overview of the beneficial and detrimental effects of NPs on stress response pathways with a focus on NP-protein interactions. Depending upon the particular NP, experimental model system, and dose and exposure conditions, the introduction of NPs may have either positive or negative effects. Cellular processes such as the development of oxidative stress, the initiation of the inflammatory response, mitochondrial function, detoxification, and alterations to signaling pathways are all affected by the introduction of NPs. In terms of tissue-specific effects, the local microenvironment can have a profound effect on whether an NP is beneficial or harmful to cells. Interactions of NPs with metal-binding proteins (zinc, copper, iron and calcium) affect both their structure and function. This review will provide insights into the current knowledge of protein-based nanotoxicology and closely examines the targets of specific NPs.

Aerosol-Cell Exposure System Applied to Semi-Adherent Cells for Aerosolization of Lung Surfactant and Nanoparticles Followed by High Quality RNA Extraction

Nanoparticle toxicity assessments have moved closer to physiological conditions while trying to avoid the use of animal models. An example of new in vitro exposure techniques developed is the exposure of cultured cells at the air-liquid interface (ALI), particularly in the case of respiratory airways. While the commercially available VITROCELL^® Cloud System has been applied for the delivery of aerosolized substances to adherent cells under ALI conditions, it has not yet been tested on lung surfactant and semi-adherent cells such as alveolar macrophages, which are playing a pivotal role in the nanoparticle-induced immune response.

OBJECTIVES

In this work, we developed a comprehensive methodology for coating semi-adherent lung cells cultured at the ALI with aerosolized surfactant and subsequent dose-controlled exposure to nanoparticles (NPs). This protocol is optimized for subsequent transcriptomic studies.

METHODS

Semi-adherent rat alveolar macrophages NR8383 were grown at the ALI and coated with lung surfactant through nebulization using the VITROCELL^® Cloud 6 System before being exposed to TiO₂ NM105 NPs. After NP exposures, RNA was extracted and its quantity and quality were measured.

RESULTS

The VITROCELL^® Cloud system allowed for uniform and ultrathin coating of cells with aerosolized surfactant mimicking physiological conditions in the lung. While nebulization of 57 μL of 30 mg/mL TiO₂ and 114 μL of 15 mg/mL TiO₂ nanoparticles yielded identical cell delivered dose, the reproducibility of dose as well as the quality of RNA extracted were better for 114 μL.

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.

Ribosome profiling reveals translatome remodeling in cancer cells in response to zinc oxide nanoparticles

The anticancer effect of zinc oxide nanoparticles (ZnO NPs) largely relies on cellular responses such as alteration of gene expression. Although ZnO NPs have been reported to induce transcriptional changes, the potential of ZnO NPs to affect cellular translatome remains largely unknown. Using ribosome profiling, we demonstrated that the transcription of 78 genes and the translation of 1,448 genes are affected during one hour of ZnO NPs exposure in A549 human lung cancer cells. The mitogen-activated protein kinase (MAPK) pathway is up-regulated upon ZnO NP treatment. The upstream open reading frame (uORF) plays a pervasive role in the induction of up-regulated genes, including TLNRD1 and CCNB1IP1. Knockdown of TLNRD1 or CCNB1IP1 reduces ZnO NP-induced cytotoxicity. Together, our study characterizes the landscape of translational alteration under ZnO NPs treatment and provides potential targets to augment the anticancer effect of ZnO NPs.

Sirtuins as molecular targets, mediators, and protective agents in metal-induced toxicity

Metal dyshomeostasis, and especially overexposure, is known to cause adverse health effects due to modulation of a variety of metabolic pathways. An increasing body of literature has demonstrated that metal exposure may affect SIRT signaling, although the existing data are insufficient. Therefore, in this review we discuss the available data (PubMed-Medline, Google Scholar) on the influence of metal overload on sirtuin (SIRT) signaling and its association with other mechanisms involved in metal-induced toxicity. The existing data demonstrate that cadmium (Cd), mercury (Hg), arsenic (As), lead (Pb), aluminium (Al), hexavalent chromium (Cr^VI), manganese (Mn), iron (Fe), and copper (Cu) can inhibit SIRT1 activity. In addition, an inhibitory effect of Cd, Pb, As, and Fe on SIRT3 has been demonstrated. In turn, metal-induced inhibition of SIRT was shown to affect deacetylation of target proteins including FOXO, PGC1α, p53 and NF-kB. Increased acetylation downregulates PGC1α signaling pathway, resulting in cellular altered redox status and increased susceptibility to oxidative stress, as well as decreased mitochondrial biogenesis. Lower rates of LKB1 deacetylation may be responsible for metal-induced decreases in AMPK activity and subsequent metabolic disturbances. A shift to the acetylated FOXO results in increased expression of pro-apoptotic genes which upregulates apoptosis together with increased p53 signaling. Correspondingly, decreased NF-kB deacetylation results in upregulation of target genes of proinflammatory cytokines, enzymes, and cellular adhesion molecules thus promoting inflammation. Therefore, alterations in sirtuin activity may at least partially mediate metal-induced metabolic disturbances that have been implicated in neurotoxicity, nephrotoxicity, cardiotoxicity, and other toxic effects of heavy metals.

Harmful effects of metal(loid) oxide nanoparticles

Abstract

The incorporation of nanomaterials (NMs), including metal(loid) oxide (MOx) nanoparticles (NPs), in the most diversified consumer products, has grown enormously in recent decades. Consequently, the contact between humans and these materials increased, as well as their presence in the environment. This fact has raised concerns and uncertainties about the possible risks of NMs to human health and the adverse effects on the environment. These concerns underline the need and importance of assessing its nanosecurity. The present review focuses on the main mechanisms underlying the MOx NPs toxicity, illustrated with different biological models: release of toxic ions, cellular uptake of NPs, oxidative stress, shading effect on photosynthetic microorganisms, physical restrain and damage of cell wall. Additionally, the biological models used to evaluate the potential hazardous of nanomaterials are briefly presented, with particular emphasis on the yeast Saccharomyces cerevisiae, as an alternative model in nanotoxicology. An overview containing recent scientific advances on cellular responses (toxic symptoms exhibited by yeasts) resulting from the interaction with MOx NPs (inhibition of cell proliferation, cell wall damage, alteration of function and morphology of organelles, presence of oxidative stress bio-indicators, gene expression changes, genotoxicity and cell dead) is critically presented. The elucidation of the toxic modes of action of MOx NPs in yeast cells can be very useful in providing additional clues about the impact of NPs on the physiology and metabolism of the eukaryotic cell. Current and future trends of MOx NPs toxicity, regarding their possible impacts on the environment and human health, are discussed.

Key points

• The potential hazardous effects of MOx NPs are critically reviewed.

• An overview of the main mechanisms associated with MOx NPs toxicity is presented.

• Scientific advances about yeast cell responses to MOx NPs are updated and discussed.

Cytotoxicity of black phosphorus quantum dots on lung-derived cells and the underlying mechanisms

Black phosphorus quantum dots (BP-QDs) are a new type of zero-dimensional (0D) nanomaterial that has been widely used due of their superior properties in many biomedical fields, but limited studies have focused on the biocompatibility of BP-QDs, particularly in the respiratory system. In this study, we investigated the potential lung cell toxicity of BP-QDs in vitro. Two human lung-derived cells, A549 and Beas-2B, were treated with 5∼20 μg/mL BP-QDs for 24 h. The results showed that BP-QDs triggered significant lung cell toxicity, including a dose-dependent decrease in cell viability, lactate dehydrogenase (LDH) leakage, cell shape changes, cellular oxidative stress and cell cycle arrest. In addition, pretreatment with the classical phagocytosis inhibitor cytochalasin D (Cyto D) alleviated the decrease in cell viability and LDH leakage induced by BP-QDs. In contrast, BP-QDs induced the production of cellular reactive oxygen species (ROS) and decreases in the glutathione level, whereas the ROS scavenger N-acetyl-L-cysteine (NAC) could protect A549 and Beas-2B cells from BP-QD-induced cellular oxidative stress. Taken together, the results from this study indicate that the potential toxic effects and mechanisms of BP-QDs in two different human lung cells should be considered to evaluate the lung cell safety of BP-QDs.

Systematic Review of Multi-Omics Approaches to Investigate Toxicological Effects in Macrophages

Insights into the modes of action (MoAs) of xenobiotics are of utmost importance for the definition of adverse outcome pathways (AOPs), which are essential for a mechanism-based risk assessment. A well-established strategy to reveal MoAs of xenobiotics is the use of omics. However, often an even more comprehensive approach is needed, which can be achieved using multi-omics. Since the immune system plays a central role in the defense against foreign substances and pathogens, with the innate immune system building a first barrier, we systematically reviewed multi-omics studies investigating the effects of xenobiotics on macrophages. Surprisingly, only nine publications were identified, combining proteomics with transcriptomics or metabolomics. We summarized pathways and single proteins, transcripts, or metabolites, which were described to be affected upon treatment with xenobiotics in the reviewed studies, thus revealing a broad range of effects. In summary, we show that macrophages are a relevant model system to investigate the toxicological effects induced by xenobiotics. Furthermore, the multi-omics approaches led to a more comprehensive overview compared to only one omics layer with slight advantages for combinations that complement each other directly, e.g., proteome and metabolome.

Zinc ferrate nanoparticles for applications in medicine: synthesis, physicochemical properties, regulation of macrophage functions, and in vivo safety evaluation

Zinc ferrate nanoparticles (ZnFe₂O₄ NPs) have attracted enormous interest as potential nanomaterials. The purpose of this study was to examine the in vitro macrophages toxicity, in vivo safety, and immunogenicity. Three kinds of ZnFe₂O₄ NPs with different shapes (round, litchi, and raspberry), nano-sizes, and pores were successfully prepared. In vitro experiments showed that ZnFe₂O₄ NPs caused no cytotoxicity against the RAW 264.7 cells up to administered dose of 200 μg/mL, enhanced proinflammatory cytokine TNF-α, and costimulatory marker CD86 expression in the RAW 264.7 cells. Interestingly, ZnFe₂O₄ NPs reduced ROS expression, which was inconsistent with common metal oxide NPs such as iron oxide (Fe₃O₄) NPs and zinc oxide (ZnO) NPs. ZnFe₂O₄ NPs improved the RAW 264.7 cells phagocytosed more neutral red. There was no obvious difference in body weight, the number of immune cells, organ index, and expression of inflammatory factors in serum of rats administrated intravenously and subcutaneously on day 21 after treatment by ZnFe₂O₄ NPs in comparison with the blank control. These results demonstrated that ZnFe₂O₄ NPs slightly enhanced the function of the RAW 264.7 cells in vitro but caused no obvious toxicity to macrophages as well as rat blood cells, and low immunogenicity in rats, suggesting that ZnFe₂O₄ NPs as a biocompatible nanomaterials achieved potential for bioapplication in the future.

DNA Methylation in Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) is a lung disease affected by both genetic and environmental factors. Therefore, the role of epigenetics in the pathogenesis of COPD has attracted much attention. As one of the three epigenetic mechanisms, DNA methylation has been extensively studied in COPD. The present review aims at overviewing the effect of DNA methylation on etiology, pathogenesis, pathophysiological changes, and complications of COPD. The clarification of aberrant methylation of target genes, which play important roles in the initiation and progression of COPD, will provide new disease-specific biomarker and targets for early diagnosis and therapy.

Roles of acyl-CoA synthetase long-chain family member 5 and colony stimulating factor 2 in inhibition of palmitic or stearic acids in lung cancer cell proliferation and metabolism

Lung cancer is a heterogeneous and complex disease with the highest incidence and mortality rate. The present study aims at defining the lung cancer phenome specificity of lipidomic profiles, screening target lipid-dependent transcriptional alternations, identifying target lipid-associated target genes, and exploring molecular mechanisms. Lung cancer-specific and lung cancer subtype-specific target lipids palmitic acid (C16:0) and stearic acid (C18:0) were found as target lipids by integrating clinical phenomics, lipidomics, and transcriptomics and exhibited antiproliferative effects in sensitive cells. The metabolism-associated gene ACSL5 or inflammation-associated gene CCL3 was identified in lung adenocarcinoma or small lung cancer cells, respectively. C16:0 or C18:0 could upregulate ACSL5 or CSF2 expression in a time- and dose-dependent pattern, and the deletion of both genes led to the insensitivity of cells. Target lipids increased the expression of PDK4 gene in different patterns and inhibited cell proliferation through alterations of intracellular energy. Thus, our data provide a new strategy to investigate the trans-points between clinical and phenomics and lipidomics and target lipid-associated molecular mechanisms to benefit from the discovery of new therapies.

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.