Zinc oxide nanoparticles induce human tenon fibroblast apoptosis through reactive oxygen species and caspase signaling pathway

Immunotoxicity of metal and metal oxide nanoparticles: from toxic mechanisms to metabolism and outcomes

The influence of metal and metal oxide nanomaterials on various fields since their discovery has been remarkable. They have unique properties, and therefore, have been employed in specific applications, including biomedicine. However, their potential health risks cannot be ignored. Several studies have shown that exposure to metal and metal oxide nanoparticles can lead to immunotoxicity. Different types of metals and metal oxide nanoparticles may have a negative impact on the immune system through various mechanisms, such as inflammation, oxidative stress, autophagy, and apoptosis. As an essential factor in determining the function and fate of immune cells, immunometabolism may also be an essential target for these nanoparticles to exert immunotoxic effects in vivo. In addition, the biodegradation and metabolic outcomes of metal and metal oxide nanoparticles are also important considerations in assessing their immunotoxic effects. Herein, we focus on the cellular mechanism of the immunotoxic effects and toxic effects of different types of metal and metal oxide nanoparticles, as well as the metabolism and outcomes of these nanoparticles in vivo. Also, we discuss the relationship between the possible regulatory effect of nanoparticles on immunometabolism and their immunotoxic effects. Finally, we present perspectives on the future research and development direction of metal and metal oxide nanomaterials to promote scientific research on the health risks of nanomaterials and reduce their adverse effects on human health.

Non-ROS-Mediated Cytotoxicity of ZnO and CuO in ML-1 and CA77 Thyroid Cancer Cell Lines

Metal oxide nanoparticles (MONPs) are widely used in agriculture and food development but there is little understanding of how MONPs, including ZnO, CuO, TiO₂, and SnO₂, impact human health and the environment. Our growth assay revealed that none of these (up to 100 µg/mL) negatively affect viability in the budding yeast, Saccharomyces cerevisiae. In contrast, both human thyroid cancer cells (ML-1) and rat medullary thyroid cancer cells (CA77) displayed a significant reduction in cell viability with the treatment of CuO and ZnO. The production of reactive oxygen species (ROS) in these cell lines, when treated with CuO and ZnO, was found to be not significantly altered. However, levels of apoptosis with ZnO and CuO were increased, which led us to conclude that the decreased cell viability is mainly caused by non-ROS-mediated cell death. Consistently, data from our RNAseq studies identified differentially regulated pathways associated with inflammation, Wnt, and cadherin signaling across both cell lines, ML-1, and CA77, after ZnO or CuO MONP treatment. Results from gene studies further support non-ROS-mediated apoptosis being the main factor behind decreased cell viability. Together, these findings provide unique evidence that the apoptosis in response to treatment of CuO and ZnO in these thyroid cancer cells was not mainly due to oxidative stress, but to the alteration of a range of signal cascades that promotes cell death.

Mitochondrial Dysfunction Induced by Zinc Oxide Nanoparticles

The constant evolution and applications of metallic nanoparticles (NPs) make living organisms more susceptible to being exposed to them. Among the most used are zinc oxide nanoparticles (ZnO-NPs). Therefore, understanding the molecular effects of ZnO-NPs in biological systems is extremely important. This review compiles the main mechanisms that induce cell toxicity by exposure to ZnO-NPs and reported in vitro research models, with special attention to mitochondrial damage. Scientific evidence indicates that in vitro ZnO-NPs have a cytotoxic effect that depends on the size, shape and method of synthesis of ZnO-NPs, as well as the function of the cells to which they are exposed. ZnO-NPs come into contact with the extracellular region, leading to an increase in intracellular [Zn2+] levels. The mechanism by which intracellular ZnO-NPs come into contact with organelles such as mitochondria is still unclear. The mitochondrion is a unique organelle considered the “power station” in the cells, participates in numerous cellular processes, such as cell survival/death, multiple biochemical and metabolic processes, and holds genetic material. ZnO-NPs increase intracellular levels of reactive oxygen species (ROS) and, in particular, superoxide levels; they also decrease mitochondrial membrane potential (MMP), which affects membrane permeability and leads to cell death. ZnO-NPs also induced cell death through caspases, which involve the intrinsic apoptotic pathway. The expression of pro-apoptotic genes after exposure to ZnO-NPs can be affected by multiple factors, including the size and morphology of the NPs, the type of cell exposed (healthy or tumor), stage of development (embryonic or differentiated), energy demand, exposure time and, no less relevant, the dose. To prevent the release of pro-apoptotic proteins, the damaged mitochondrion is eliminated by mitophagy. To replace those mitochondria that underwent mitophagy, the processes of mitochondrial biogenesis ensure the maintenance of adequate levels of ATP and cellular homeostasis.

Meta-analysis of in-vitro cytotoxicity evaluation studies of zinc oxide nanoparticles: Paving way for safer innovations

Nano-based products have shown their daunting presence in several sectors. Among them, Zinc Oxide (ZnO) nanoparticles wangled the reputation of providing "next-generation solutions" and are being utilized in plethora of products. Their widespread application has led to increased exposure of these particles, raising concerns regarding toxicological repercussions to the human health and environment. The diversity, complexity, and heterogeneity in the available literature, along with correlation of befitting attributes, makes it challenging to develop one systematic framework to predict this toxicity. The present study aims at developing predictive modelling framework to tap the prospective features responsible for causing cytotoxicity in-vitro on exposure to ZnO nanoparticles. Rigorous approach was used to mine the information from complete body of evidence published to date. The attributes, features and experimental conditions were systematically extracted to unmask the effect of varied features. 1240 data points from 76 publications were obtained, containing 14 qualitative and quantitative attributes, including physiochemical properties of nanoparticles, cell culture and experimental parameters to perform meta-analysis. For the first time, the efforts were made to investigate the degree of significance of attributes accountable for causing cytotoxicity on exposure to ZnO nanoparticles. We show that in-vitro cytotoxicity is closely related with dose concentration of nanoparticles, followed by exposure time, disease state of the cell line and size of these nanoparticles among other attributes.

Metallic Engineered Nanomaterials and Ocular Toxicity: A Current Perspective

The ocular surface, comprised of the transparent cornea, conjunctiva, and protective tear film, forms a protective barrier defending deeper structures of the eye from particulate matter and mechanical trauma. This barrier is routinely exposed to a multitude of naturally occurring and engineered nanomaterials (ENM). Metallic ENMs are particularly ubiquitous in commercial products with a high risk of ocular exposure, such as cosmetics and sunscreens. Additionally, there are several therapeutic uses for metallic ENMs owing to their attractive magnetic, antimicrobial, and functionalization properties. The increasing commercial and therapeutic applications of metallic ENMs come with a high risk of ocular exposure with poorly understood consequences to the health of the eye. While the toxicity of metallic ENMs exposure has been rigorously studied in other tissues and organs, further studies are necessary to understand the potential for adverse effects and inform product usage for individuals whose ocular health may be compromised by injury, disease, or surgical intervention. This review provides an update of current literature on the ocular toxicity of metallic ENMs in vitro and in vivo, as well as the risks and benefits of therapeutic applications of metallic ENMs in ophthalmology.

Cytotoxicity of Metal-Based Nanoparticles: From Mechanisms and Methods of Evaluation to Pathological Manifestations

Metal-based nanoparticles (NPs) are particularly important tools in tissue engineering-, drug carrier-, interventional therapy-, and biobased technologies. However, their complex and varied migration and transformation pathways, as well as their continuous accumulation in closed biological systems, cause various unpredictable toxic effects that threaten human and ecosystem health. Considerable experimental and theoretical efforts have been made toward understanding these cytotoxic effects, though more research on metal-based NPs integrated with clinical medicine is required. This review summarizes the mechanisms and evaluation methods of cytotoxicity and provides an in-depth analysis of the typical effects generated in the nervous, immune, reproductive, and genetic systems. In addition, the challenges and opportunities are discussed to enhance future investigations on safer metal-based NPs for practical commercial adoption.

Particles rather than released Zn2+ from ZnO nanoparticles aggravate microplastics toxicity in early stages of exposed zebrafish and their unexposed offspring

Knowledge on the interaction between microplastics (MPs) and zinc oxide nanoparticles (ZnO NPs) is limited. Here, we investigated effects of embryo-larvae exposure to 500 μg/L polystyrene MPs (5 µm), 1200 μg/L ZnO NPs (< 100 nm), 500 μg/L dissolved Zn²⁺ from ZnSO4^, and the mixtures of MPs and ZnO NPs or ZnSO4 on exposed F0 larvae and unexposed F1 larvae. Consequently, ZnO particles adhered to MPs surfaces rather than Zn²⁺, and increased Zn transport into larvae. Growth inhibition, oxidative stress, apoptosis, and disturbance of growth hormone and insulin-like growth factor (GH/IGF) axis were induced by MPs and ZnO NPs alone, which were further aggravated by their co-exposure in F0 larvae. MPs + ZnO increased apoptotic cells in the gill and esophagus compared with MPs and ZnO NPs alone. Reduced growth and antioxidant capacity and down-regulated GH/IGF axis were merely observed in F1 larvae from F0 parents exposed to MPs + ZnO. Contrary to ZnO NPs, dissolved Zn²⁺ reversed MPs toxicity, suggesting the protective role of Zn²⁺ may be not enough to ameliorate thfie negative effects of ZnO particles. To summarize, we found that particles rather than released Zn²⁺ from ZnO nanoparticles amplified MPs toxicity in early stages of exposed zebrafish and their unexposed offspring.

Assessment of Potential Toxicity of Onion-like Carbon Nanoparticles from Grilled Turbot Scophthalmus maximus L

Although the presence of foodborne nanoparticles was confirmed in grilled fish in a previous study, the evaluation of potential health risks of these NPs was insufficient. In the present study, the potential toxicity of onion-like carbon nanoparticles (OCNPs) separated from grilled turbot Scophthalmus maximus L. was evaluated using mouse osteoblasts cells model and zebrafish (Danio rerio) model. Cytotoxicity evaluation revealed that the OCNPs penetrated into the MC3T3-E1 cells without arousing cell morphology changes. No evident apoptosis or damage of cells was observed with increasing OCNPs’ concentration to 20 mg/mL. In the hemolysis test, OCNPs did not show an obvious hemolysis effect on red blood cells. In the acute toxicity test, the LC₅₀ value (212.431 mg/L) of OCNPs to zebrafish showed a weak acute toxicity. In subacute toxicity test, after exposure to OCNPs (30 mg/L, 40 mg/L) for 10 days, a significant increase of reactive oxygen species level of zebrafish was observed. Meanwhile, redundant ROS content caused inhibition to several antioxidant enzymes and induced lipid and protein peroxidation damages according to the upregulation of malondialdehyde and protein carbonyl levels. The chronic toxicity test results indicated that oxidative stress was only observed in the high concentration group of OCNPs-treated zebrafish.

Zinc oxide nanoparticle-triggered oxidative stress and autophagy activation in human tenon fibroblasts

Glaucoma is a leading cause of irreversible blindness worldwide due to elevated intraocular pressure, and filtering surgery can efficiently control intraocular pressure of glaucoma patients. However, failure of filtering surgery commonly results from scarring formation at the surgical site, in which fibroblast proliferation plays an essential role in the scarring process. Our previous study has demonstrated that zinc oxide (ZnO) nanoparticles could efficiently inhibit human tenon fibroblasts (HTFs) proliferation. The present study aimed to explore the underlying mechanism involved in oxidative stress and autophagy signaling in zinc oxide (ZnO) nanoparticles-induced inhibition of HTFs proliferation. In this study, we investigated the effect of ZnO nanoparticles on HTFs proliferation, mitochondrial function, ATP production and nuclear morphology. Moreover, we also explored the interactions between ZnO nanoparticles and HTFs, investigated the influence of ZnO nanoparticles on the autophagosome formation, the expression of autophagy-related 5 (Atg5), Atg12 and Becn1 (Beclin 1), and the level of light chain 3 (LC3). The results suggested that ZnO nanoparticles can efficiently inhibit HTFs proliferation, disrupt the mitochondrial function, attenuate the adenosine triphosphate (ATP) generation, and damage the nuclear morphology of HTFs. Exposure of HTFs to ZnO nanoparticles can also induce the shifted peak, elevate the expression of Atg5, Atg12 and Becn1, enhance the autophagosome formation, and promote the LC3 expression, and thus activate autophagy signaling. Overall, ZnO nanoparticles can apparently trigger oxidative stress and activate autophagy signaling in HTFs, and thus inhibit HTFs proliferation and mediate HTFs apoptosis.

The inhibitory effect Polygonum Cillinerve polysaccharide on transmissible gastroenteritis virus of swine

Transmissible gastroenteritis virus of swine (TGEV) is one kind of the main pathogens causing viral diarrhea in pig. In this study, the inhibitory effect of Polygonum Cillinerve polysaccharide (PCP) on TGEV was studied. Firstly, MTT method was used to measure the cell viability of PCP. Then Hoechst 33258 fluorescence staining, Annexin V-FITC/PI fluorescence staining, real-time PCR and western blot were used to explore the effect of PCP on inhibiting TGEV. The results showed that PCP could significantly reduce the apoptosis rate induced by TGEV, reduce the expression of ROS, reduce TGEV replication, increase the expression levels of Bcl-2 and Bax genes, increase the expression of Bcl-2 protein, decreased the expression of Cyto c protein, and reduce the amount of cleaved caspase 3. Therefore, PCP had the better inhibitory effect on TGEV, which provided a certain theoretical basis for the prevention and treatment of TGEV.

pH-Responsive Pluronic F127-Lenvatinib-Encapsulated Halogenated Boron-Dipyrromethene Nanoparticles for Combined Photodynamic Therapy and Chemotherapy of Liver Cancer

Combination therapy such as photodynamic therapy (PDT)-enhanced chemotherapy is regarded as a promising strategy for cancer treatment. Boron-dipyrromethene (BODIPY), as close relatives of porphyrins, was widely used in PDT. However, poor water solubility, rapid metabolism by the body and lack of targeting limits its clinical application. Lenvatinib, as the first-line drug for molecular-targeted therapy of liver cancer, restricted its clinical application for its side effects. Herein, to achieve the synergy between PDT and chemotherapy, we synthesized two halogenated BODIPY, BDPBr₂ and BDPCl₂, which were prepared into self-assembly nanoparticles with lenvatinib, and were encapsulated with Pluronic F127 through the nanoprecipitation method, namely, LBPNPs (LBBr₂ NPs and LBCl₂ NPs). The fluorescence quantum yields of LBPNPs were 0.73 and 0.71, respectively. The calculated loading rates of lenvatinib for LBBr₂ NPs and LBCl₂ NPs were 11.8 and 10.2%, respectively. LBPNPs can be hydrolyzed under weakly acidic conditions (pH 5.0) to generate reactive oxygen species (ROS), and the release rate of lenvatinib reached 88.5 and 82.4%. Additionally, LBPNPs can be effectively taken up by Hep3B and Huh7 liver cancer cells, releasing halogenated BODIPY and lenvatinib in the acidic environment of tumor cells to enhance the targeting performance of chemotherapeutics. Compared with free lenvatinib and separate halogenated BODIPY, LBPNPs can inhibit tumor growth more effectively through pH-responsive chemo/photodynamic synergistic therapy and significantly promote the cascade of caspase apoptotic protease. This study shows that LBPNPs can be a promising nanotheranostic agent for synergetic chemo/photodynamic liver cancer therapy.

Nanomedicines for the treatment of glaucoma: Current status and future perspectives

Glaucoma is the global leading cause of irreversible blindness. It is a chronic progressive disorder and, therefore, often requires long-term management with drugs on patients' discretion. However, there is a shortage of antiglaucoma drugs in the current market due to their low bioavailability. This is because there are multiple biological barriers of the human eyes, thereby leading to increased demands for frequent dosage regimen per day of these drugs, which could result in concomitant side effects and eventually reduced patient compliance. Recently, nanomedicines have become optimized alternatives to conventional ophthalmic formulations due to advantages of improved barrier permeability, sustained drug release, tissue targeting, and lowered systemic absorption of instilled medications. These merits provide the active ingredients in these nanomedicines an effective manner to reach the ideal concentrations at sites of damaged nerves, offering a promising platform for neuroprotective treatment of these conditions. In this study, nanomedicines and nanomedicine-based novel strategies for pharmacotherapy of glaucoma were reviewed, including liposomes, niosomes, nanoparticles, and dendrimers. This article intends to offer a comprehensive review of frontier progresses as well as hotspots and issues that appeared in the field of nanomedicines, which may enable a practical flourish in the future. STATEMENT OF SIGNIFICANCE: Recent novel pharmaceutical strategies toward glaucoma, a chronic blinding ocular disease that currently requires frequent daily dosage regimen, based on nanomedicines and nanomaterials have been comprehensively reviewed in this manuscript. The collection of field hotspots and issues in the late years should offer a quick grasp of the general concept and up-to-date threads upon the refinement of existing treatment patterns for glaucoma. Meanwhile, the Conclusion and Future Perspective section given at the end of the text brings out the possible shortages and opinions in terms of ideal research direction, which hopefully could facilitate a future practical flourish in the area.

ZnO nanoparticles as photodegradation agent controlled by morphology and boron doping

ZnO nanoparticles with different morphology and doping possess different atomic planes at their interfaces. This changed their catalytic efficiency during degradation experiments with dyes, significantly dependent also on used dopant concentrations.