Titanium dioxide nanoparticles induce strong oxidative stress and mitochondrial damage in glial cells

Effect of moringa seed extract in chlorpyrifos-induced cerebral and ocular toxicity in mice

Chlorpyrifos (CPF) is one of the most commonly used organophosphosphate-based (OP) insecticides. Its wide use has led to higher morbidity and mortality, especially in developing countries. Moringa seed extracts (MSE) have shown neuroprotective activity, antioxidant, anti-inflammatory, and antibacterial features. The literature lacks data investigating the role of MSE against CPF-induced cerebral and ocular toxicity in mice. Therefore, we aim to investigate this concern. A total of 40 mature male Wistar Albino mice were randomly distributed to five groups. Initially, they underwent a one-week adaptation period, followed by a one-week treatment regimen. The groups included a control group that received saline, MSE 100 mg/kg, CPF 12 mg/kg, CPF-MSE 50 mg/kg, and CPF-MSE 100 mg/kg. After the treatment phase, analyses were conducted on serum, ocular, and cerebral tissues. MSE100 and CPF-MSE100 normalized the pro-inflammatory markers (interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α)) and AChE serum levels. CPF-MSE50 significantly enhanced these serum levels compared to CPF; however, it showed higher levels compared to the control. Moreover, the tissue analysis showed a significant decrease in oxidative stress (malondialdehyde (MDA) and nitric oxide (NO)) and an increase in antioxidant markers (glutathione (GSH), glutathione peroxidase (GSH-PX)), superoxide dismutase (SOD), and catalase (CAT) in the treated groups compared to CPF. Importantly, the significance of these effects was found to be dose-dependent, particularly evident in the CPF-MSE100 group. We conclude that MSE has a promising therapeutic effect in the cerebral and ocular tissues of CPF-intoxicated mice, providing a potential solution for OP public health issues.

The toxicological effects of nano titanium dioxide on target organs and mechanisms of toxicity

Nano-titanium dioxide (TiO2 NPs) is widely used for its extremely high stability, corrosion resistance, and photocatalytic properties and has penetrated into various fields of production and life. Assessing its toxicity to different organs should be a key part of preclinical toxicity assessment of TiO2 NPs, which is relatively incomprehensive yet. Therefore, this review focuses on the toxic effects of TiO2 NPs on various organs in mammals and biological mechanisms from different organs. The commonality of toxic effects on various target organs reflected in tissue structure damage and dysfunction, such as liver damage and dysfunction; pulmonary fibrosis; and renal impairment (including hematuria and nephritis); damage of brain tissue and neurons; alteration of intestinal villi; and weight loss. And effects on the reproductive system are affected by different sexes, including ovarian dysfunction, testicular development damage, and sperm viability reduction. We believe that the toxic mechanisms of TiO2 NPs in target organs have commonalities, such as oxidative stress, inflammatory responses, and organelle damage. However, different target organ toxicities also have their specificities. TiO2 NPs disturb the intestinal flora and cause undesirable changes in feces products. And in spleen are infiltration of neutrophils and lymphadenopathy and eventually immune deficiency. Although the toxic pathways are different, but there may be a close link between the different toxic pathways. In this article, the main manifestations of the toxic effects of titanium dioxide nanoparticles on major mammalian organs are reviewed, in order to provide basic data for their better application from a medical perspective.

Neurotoxicity of Titanium Dioxide Nanoparticles: A Comprehensive Review

The increasing use of titanium dioxide nanoparticles (TiO2 NPs) across various fields has led to a growing concern regarding their environmental contamination and inevitable human exposure. Consequently, significant research efforts have been directed toward understanding the effects of TiO2 NPs on both humans and the environment. Notably, TiO2 NPs exposure has been associated with multiple impairments of the nervous system. This review aims to provide an overview of the documented neurotoxic effects of TiO2 NPs in different species and in vitro models. Following exposure, TiO2 NPs can reach the brain, although the specific mechanism and quantity of particles that cross the blood-brain barrier (BBB) remain unclear. Exposure to TiO2 NPs has been shown to induce oxidative stress, promote neuroinflammation, disrupt brain biochemistry, and ultimately impair neuronal function and structure. Subsequent neuronal damage may contribute to various behavioral disorders and play a significant role in the onset and progression of neurodevelopmental or neurodegenerative diseases. Moreover, the neurotoxic potential of TiO2 NPs can be influenced by various factors, including exposure characteristics and the physicochemical properties of the TiO2 NPs. However, a systematic comparison of the neurotoxic effects of TiO2 NPs with different characteristics under various exposure conditions is still lacking. Additionally, our understanding of the underlying neurotoxic mechanisms exerted by TiO2 NPs remains incomplete and fragmented. Given these knowledge gaps, it is imperative to further investigate the neurotoxic hazards and risks associated with exposure to TiO2 NPs.

Development of a Polymeric Pharmacological Nanocarrier System as a Potential Therapy for Spinocerebellar Ataxia Type 7

Spinocerebellar ataxia type 7 (SCA7) is an autosomal-dominant inherited disease characterized by progressive ataxia and retinal degeneration. SCA7 belongs to a group of neurodegenerative diseases caused by an expanded CAG repeat in the disease-causing gene, resulting in aberrant polyglutamine (polyQ) protein synthesis. PolyQ ataxin-7 is prone to aggregate in intracellular inclusions, perturbing cellular processes leading to neuronal death in specific regions of the central nervous system (CNS). Currently, there is no treatment for SCA7; however, a promising approach successfully applied to other polyQ diseases involves the clearance of polyQ protein aggregates through pharmacological activation of autophagy. Nonetheless, the blood-brain barrier (BBB) poses a challenge for delivering drugs to the CNS, limiting treatment effectiveness. This study aimed to develop a polymeric nanocarrier system to deliver therapeutic agents across the BBB into the CNS. We prepared poly(lactic-co-glycolic acid) nanoparticles (NPs) modified with Poloxamer188 and loaded with rapamycin to enable NPs to activate autophagy. We demonstrated that these rapamycin-loaded NPs were successfully taken up by neuronal and glial cells, demonstrating high biocompatibility without adverse effects. Remarkably, rapamycin-loaded NPs effectively cleared mutant ataxin-7 aggregates in a SCA7 glial cell model, highlighting their potential as a therapeutic approach to fight SCA7 and other polyQ diseases.

Comprehensive Analysis of Titanium Oxide Nanoparticle Size and Surface Properties on Neuronal PC-12 Cells: Unraveling Cytotoxicity, Dopaminergic Gene Expression, and Acetylcholinesterase Inhibition

Titanium oxide nanoparticles can penetrate the blood-brain barrier, infiltrate the central nervous system, and induce neurotoxicity. One of the most often utilized nanoparticles has been investigated for their neurotoxicity in many studies. Nonetheless, there remains an unexplored aspect regarding the comparative analysis of particles varying in size and nanoparticles of identical dimensions, both with and devoid of surface coating. In the current study, we synthesized two differently sized nanoparticles, TiO2-10 (10 nm) and TiO2-22 (22 nm), and nanoparticles of the same size but with a polyvinylpyrrolidone surface coating (TiO2-PVP, 22 nm) and studied their toxic effects on neural PC-12 cells. The results highlighted significant dose- and time-dependent cytotoxicity at concentrations ≥10 μg/mL. The exposure of TiO2 nanoparticles significantly elevated reactive oxygen and nitrogen species levels, IL-6 and TNF-α levels, altered the mitochondrial membrane potential, and enhanced apoptosis-related caspase-3 activity, irrespective of size and surface coating. The interaction of the nanoparticles with acetylcholinesterase enzyme activity was also investigated, and the results revealed a dose-dependent suppression of enzymatic activity. However, the gene expression studies indicated no effect on the expression of all six genes associated with the dopaminergic system upon exposure to 10 μg/mL for any nanoparticle. The results demonstrated no significant difference between the outcomes of TiO2-10 and TiO2-22 NPs. However, the polyvinylpyrrolidone surface coating was able to attenuate the neurotoxic effects. These findings suggest that as the TiO2 nanoparticles get smaller (towards 0 nm), they might promote apoptosis and inflammatory reactions in neural cells via oxidative stress, irrespective of their size.

Virulence traits and novel drug delivery strategies for mucormycosis post-COVID-19: a comprehensive review

The outbreak of a fatal black fungus infection after the resurgence of the cadaverous COVID-19 has exhorted scientists worldwide to develop a nutshell by repurposing or designing new formulations to address the crisis. Patients expressing COVID-19 are more susceptible to Mucormycosis (MCR) and thus fall easy prey to decease accounting for this global threat. Their mortality rates range around 32-70% depending on the organs affected and grow even higher despite the treatment. The many contemporary recommendations strongly advise using liposomal amphotericin B and surgery as first-line therapy whenever practicable. MCR is a dangerous infection that requires an antifungal drug administration on appropriate prescription, typically one of the following: Amphotericin B, Posaconazole, or Isavuconazole since the fungi that cause MCR are resistant to other medications like fluconazole, voriconazole, and echinocandins. Amphotericin B and Posaconazole are administered through veins (intravenously), and isavuconazole by mouth (orally). From last several years so many compounds are developed against invasive fungal disease but only few of them are able to induce effective treatment against the micorals. Adjuvant medicines, more particularly, are difficult to assess without prospective randomized controlled investigations, which are challenging to conduct given the lower incidence and higher mortality from Mucormycosis. The present analysis provides insight into pathogenesis, epidemiology, clinical manifestations, underlying fungal virulence, and growth mechanisms. In addition, current therapy for MCR in Post Covid-19 individuals includes conventional and novel nano-based advanced management systems for procuring against deadly fungal infection. The study urges involving nanomedicine to prevent fungal growth at the commencement of infection, delay the progression, and mitigate fatality risk.

Interaction of Nanomaterials with Cells and Tissues

Nanomaterials have gained enormous importance in biomedicine in recent years, both in basic and applied sciences [...].

The Potential of Trichoderma-Mediated Nanotechnology Application in Sustainable Development Scopes

The environmental impact of industrial development has been well-documented. The use of physical and chemical methods in industrial development has negative consequences for the environment, raising concerns about the sustainability of this approach. There is a growing need for advanced technologies that are compatible with preserving the environment. The use of fungi products for nanoparticle (NP) synthesis is a promising approach that has the potential to meet this need. The genus Trichoderma is a non-pathogenic filamentous fungus with a high degree of genetic diversity. Different strains of this genus have a variety of important environmental, agricultural, and industrial applications. Species of Trichoderma can be used to synthesize metallic NPs using a biological method that is environmentally friendly, low cost, energy saving, and non-toxic. In this review, we provide an overview of the role of Trichoderma metabolism in the synthesis of metallic NPs. We discuss the different metabolic pathways involved in NP synthesis, as well as the role of metabolic metabolites in stabilizing NPs and promoting their synergistic effects. In addition, the future perspective of NPs synthesized by extracts of Trichoderma is discussed, as well as their potential applications in biomedicine, agriculture, and environmental health.

Functionalized and Nonfunctionalized Nanosystems for Mitochondrial Drug Delivery with Metallic Nanoparticles

Background: The application of metallic nanoparticles as a novel therapeutic tool has significant potential to facilitate the treatment and diagnosis of mitochondria-based disorders. Recently, subcellular mitochondria have been trialed to cure pathologies that depend on their dysfunction. Nanoparticles made from metals and their oxides (including gold, iron, silver, platinum, zinc oxide, and titanium dioxide) have unique modi operandi that can competently rectify mitochondrial disorders. Materials: This review presents insight into the recent research reports on exposure to a myriad of metallic nanoparticles that can alter the dynamic ultrastructure of mitochondria (via altering metabolic homeostasis), as well as pause ATP production, and trigger oxidative stress. The facts and figures have been compiled from more than a hundred PubMed, Web of Science, and Scopus indexed articles that describe the essential functions of mitochondria for the management of human diseases. Result: Nanoengineered metals and their oxide nanoparticles are targeted at the mitochondrial architecture that partakes in the management of a myriad of health issues, including different cancers. These nanosystems not only act as antioxidants but are also fabricated for the delivery of chemotherapeutic agents. However, the biocompatibility, safety, and efficacy of using metal nanoparticles is contested among researchers, which will be discussed further in this review.

MRC-5 Human Lung Fibroblasts Alleviate the Genotoxic Effect of Fe-N Co-Doped Titanium Dioxide Nanoparticles through an OGG1/2-Dependent Reparatory Mechanism

The current study was focused on the potential of pure P25 TiO2 nanoparticles (NPs) and Fe(1%)-N co-doped P25 TiO2 NPs to induce cyto- and genotoxic effects in MRC-5 human pulmonary fibroblasts. The oxidative lesions of P25 NPs were reflected in the amount of 8-hydroxydeoxyguanosine accumulated in DNA and the lysosomal damage produced, but iron-doping partially suppressed these effects. However, neither P25 nor Fe(1%)-N co-doped P25 NPs had such a serious effect of inducing DNA fragmentation or activating apoptosis signaling. Moreover, oxo-guanine glycosylase 1/2, a key enzyme of the base excision repair mechanism, was overexpressed in response to the oxidative DNA deterioration induced by P25 and P25-Fe(1%)-N NPs.

Assessment of the Oxidative Damage and Genotoxicity of Titanium Dioxide Nanoparticles and Exploring the Protective Role of Holy Basil Oil Nanoemulsions in Rats

This study was designed to evaluate the oxidative damage, genotoxicity, and DNA damage in the liver of rats treated with titanium nanoparticles (TiO₂-NPs) with an average size of 28.0 nm and ξ-potential of - 33.97 mV, and to estimate the protective role of holy basil essential oil nanoemulsion (HBEON). Six groups of Male Sprague-Dawley rats were treated orally for 3 weeks as follows: the control group, HBEO or HBEON-treated groups (5 mg/kg b.w), TiO₂-NPs-treated group (50 mg/kg b.w), and the groups treated with TiO₂-NPs plus HBEO or HBEON. Samples of blood and tissues were collected for different analyses. The results revealed that 55 compounds were identified in HBEO, and linalool and methyl chavicol were the major compounds (53.9%, 12.63%, respectively). HBEON were semi-round with the average size and ζ-potential of 120 ± 4.5 nm and - 28 ± 1.3 mV, respectively. TiO₂-NP administration increased the serum biochemical indices, oxidative stress markers, serum cytokines, DNA fragmentation, and DNA breakages; decreased the antioxidant enzymes; and induced histological alterations in the liver. Co-administration of TiO₂-NPs plus HBEO or HBEON improved all the tested parameters and the liver histology, and HBEON was more effective than HBEO. Therefore, HEBON is a promising candidate able to protect against oxidative damage, disturbances in biochemical markers, gene expression, DNA damage, and histological changes resulting from exposure to TiO₂-NPs and may be applicable in the food and pharmaceutical sectors.

Bioaccumulation of functionalized polystyrene nanoplastics in sea cucumber Apostichopus japonicus (Selenka, 1867) and their toxic effects on oxidative stress, energy metabolism and mitochondrial pathway

Micro/nano-plastics (M/NPs) are emerging contaminants in aquatic environment, however, little knowledge regarding the adverse effects of functionalized NPs has been documented so far. This study investigated the accumulation of different polystyrene nanoplastics (PS-NPs, i.e., plain PS, carboxyl-functional PS-COOH and amino-functional PS-NH₂) at two particle sizes of 100 nm and 200 nm, and evaluated the impacts on oxidative stress, energy metabolism and mitochondrial pathway responses in intestine and respiratory tree of Apostichopus japonicus during the 20-d exposure experiment. The results showed that there were significant interactions of particle size and nanoplastic type on the accumulation of different PS-NPs. Exposure to NPs significantly increased the production of malondialdehyde, glutathione and reactive oxygen species, as well as the activities of antioxidant enzymes including glutathione reductase, superoxide dismutase and catalase, resulting in various degrees of oxidative damage in sea cucumber. The significant decrease in adenosine triphosphate content and increases in alkaline phosphatase and lactate dehydrogenase activities suggested that NPs impaired energy metabolism and modified their energy allocation. After 20-d exposure, the complex I, II and III activities in mitochondrial respiratory chain were significantly inhibited. Meanwhile, the Bax and Caspase-3 gene expression were significantly up-regulated, and Bacl-2 was down-regulated, indicating the toxicity on mitochondrial pathway of A. japonicus. The calculated IBR values elucidated the greater detriment to mitochondrial pathway than oxidative stress and energy metabolism. For 100 nm particle size, plain PS has stronger influence on all the biomarkers compared to PS-COOH/NH₂, however, the opposite trends were observed in 200 nm PS-NPs. Furthermore, 100 nm PS-NPs were recognized to be more hazardous to sea cucumber than 200 nm microbeads. These findings provide new insights for understanding the differentiated toxic effects of functionalized NPs in marine invertebrates.

DNA Damage and Apoptosis as In-Vitro Effect Biomarkers of Titanium Dioxide Nanoparticles (TiO2-NPs) and the Food Additive E171 Toxicity in Colon Cancer Cells: HCT-116 and Caco-2

This study investigated the DNA damage and apoptosis in colon cancer cells HCT-116 and Caco-2 induced by engineered titanium dioxide nanoparticles (TiO₂-NPs) (60 nm) and titanium dioxide food additive E171. MTT assays showed that both chemical forms significantly reduced cancer cell viability in a dose-dependent manner. In particular the food additive E171 induced a pronounced inhibitory effect on the growth of HCT-116 and Caco-2 cell lines (E171 IC50: 3.45 mg/L for HTC-116 and 1.88 mg/L Caco-2; TiO₂-NPs 60 nm IC50: 41.1 mg/L for HTC-116 and 14.3 mg/L for Caco-2). A low level of genotoxicity was observed in Caco-2 cells, especially when treated with TiO₂ 60 nm. Western blot analysis showed that HCT116 and Caco-2 treated cells did not overexpress apoptotic markers such as cleaved Caspase 3 and cleaved Parp. Moreover, further analysis by quantitative real-time PCR (qRT-PCR) showed that TiO₂-NPs and E171 did not promote the expression of Bax or downregulation of Bcl-2, nor did they increase the Bax/Bcl-2 ratio. The assay data provide clear evidence that TiO₂ can cause DNA damage but does not induce apoptosis or decrease long-term cell proliferation. In addition, the results show that E171 has a slightly higher level of cytotoxicity and genotoxicity. This suggests that exposure to E171 may be hazardous to health and that further research on biological effects is needed to promote safer practices in the use of this compound.

Multiple metals exposure and blood mitochondrial DNA copy number: A cross-sectional study from the Dongfeng-Tongji cohort

OBJECTIVE

Mitochondria are essential organelles that execute fundamental biological processes, while mitochondrial DNA is vulnerable to environmental insults. The aim of this study was to investigate the individual and mixture effect of plasma metals on blood mitochondria DNA copy number (mtDNAcn).

METHODS

This study involved 1399 randomly selected subcohort participants from the Dongfeng-Tongji cohort. The blood mtDNAcn and plasma levels of 23 metals were determined by using quantitative real-time polymerase chain reaction (qPCR) and inductively coupled plasma mass spectrometer (ICP-MS), respectively. The multiple linear regression was used to explore the association between each metal and mtDNAcn, and the LASSO penalized regression was performed to select the most significant metals. We also used the quantile g-computation analysis to assess the mixture effect of multiple metals.

RESULTS

Based on multiple linear regression models, each 1% increase in plasma concentration of copper (Cu), rubidium (Rb), and titanium (Ti) was associated with a separate 0.16% [β(95% CI) = 0.158 (0.066, 0.249), P = 0.001], 0.20% [β(95% CI) = 0.196 (0.073, 0.318), P = 0.002], and 0.25% [β(95% CI) = 0.245 (0.081, 0.409), P = 0.003] increase in blood mtDNAcn. The LASSO regression also confirmed Cu, Rb, and Ti as significant predictors for mtDNAcn. There was a significant mixture effect of multiple metals on increasing mtDNAcn among the elder participants (aged ≥65), with an approximately 11% increase in mtDNAcn for each quartile increase in all metal concentrations [β(95% CI) = 0.146 (0.048, 0.243), P = 0.004].

CONCLUSIONS

Our results show that plasma Cu, Rb and Ti were associated with increased blood mtDNA, and we further revealed a significant mixture effect of all metals on mtDNAcn among elder population. These findings may provide a novel perspective on the effect of metals on mitochondrial dysfunction.

Protective effects of pomegranate (Punica granatum) and its main components against natural and chemical toxic agents: A comprehensive review

BACKGROUND

Different chemical toxicants or natural toxins can damage human health through various routes such as air, water, fruits, foods, and vegetables.

PURPOSE

Herbal medicines may be safe and selective for the prevention of toxic agents due to their active ingredients and various pharmacological properties. According to the beneficial properties of pomegranate, this paper summarized the protective effects of this plant against toxic substances.

STUDY DESIGN

In this review, we focused on the findings of in vivo and in vitro studies of the protective effects of pomegranate (Punica granatum) and its active components including ellagic acid and punicalagin, against natural and chemical toxic agents.

METHODS

We collected articles from the following databases or search engines such as Web of Sciences, Google Scholar, Pubmed and Scopus without a time limit until the end of September 2022.

RESULTS

P. granatum and its constituents have shown protective effects against natural toxins such as aflatoxins, and endotoxins as well as chemical toxicants for instance arsenic, diazinon, and carbon tetrachloride. The protective effects of these compounds are related to different mechanisms such as the prevention of oxidative stress, and reduction of inflammatory mediators including tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), cyclooxygenase-2(COX-2) and nuclear factor ĸB (NF-ĸB) as well as the modulation of apoptosis, mitogen-activated protein kinase (MAPK) signaling pathways and improvement of liver or cardiac function via regulation of enzymes.

CONCLUSION

In this review, different in vitro and in vivo studies have shown that P. granatum and its active constituents have protective effects against natural and chemical toxic agents via different mechanisms. There are no clinical trials on the protective effects of P. granatum against toxic agents.

Mechano-cytoskeleton remodeling mechanism and molecular docking studies on nanosurface technology: Titania nanotube arrays

In biomedical implant technology, nanosurface such as titania nanotube arrays (TNA) could provide better cellular adaptation, especially for long-term tissue acceptance response. Mechanotransduction activities of TNA nanosurface could involve the cytoskeleton remodeling mechanism. However, there is no clear insight into TNA mechano-cytoskeleton remodeling activities, especially computational approaches. Epithelial cells have played critical interface between biomedical implant surface and tissue acceptance, particularly for long-term interaction. Therefore, this study investigates genomic responses that are responsible for cell-TNA mechano-stimulus using epithelial cells model. Findings suggested that cell-TNA interaction may improve structural and extracellular matrix (ECM) support on the cells as an adaptive response toward the nanosurface topography. More specifically, the surface topography of the TNA might improve the cell polarity and adhesion properties via the interaction of the plasma membrane and intracellular matrix responses. TNA nanosurface might engross the cytoskeleton remodeling activities for multidirectional cell movement and cellular protrusions on TNA nanosurface. These observations are supported by the molecular docking profiles that determine proteins' in silico binding mechanism on TNA. This active cell-surface revamping would allow cells to adapt to develop a protective barrier toward TNA nanosurface, thus enhancing biocompatibility properties distinctly for long-term interaction. The findings from this study will be beneficial toward nano-molecular knowledge of designing functional nanosurface technology for advanced medical implant applications.

Melatonin Protects Against Titanium Oxide-Induced Neurotoxicity: Neurochemical, Neurobehavioral, and Histopathological Evidences

titania (titanium dioxide, TiO₂) is known to induce neurotoxicity and CNS dysfunctions. Numerous studies have explored the neuroprotective effects of melatonin against neurotoxicity. This study evaluates the potential of melatonin to protect against titania-induced neurotoxicity and the role of the Keap1/Nrf2/ARE signaling pathway. One group of animals were treated with Titania (0.045 and 0.075 g/rat) alone while the other with added melatonin (1 mg/kg and 3 mg/kg) and behavioral alterations were assessed using OFT (open field test). Neurochemical and histopathological changes were also studied in the hippocampus by analyzing kelch ECH associating protein 1 (Keap1), nuclear factor erythroid 2-related factor 2 (Nrf2), and antioxidant response element (ARE). It was seen that the animals with added Melatonin had improved behavioral scores in the OFT, like anxiety and motor dysfunction triggered by TiO₂. Melatonin also reduced lipid peroxidation, ROS, GSSG, IL1β, TNFα, Bax, and Keap1 levels, but boosted GSH, GPx, GR, SOD,IL10,IL4, Bcl2, Nrf2, and ARE levels and improved quadruple mitochondrial enzyme complex activity in titania-treated animals. Histopathological examination showed melatonin induced cytoprotection against vacuolization and necrosis in granular cells of DG and pyramidal cells of CA1 area of the hippocampus. In our study, pretreatment with melatonin reduced titania-induced neurotoxicity in the hippocampus through a mechanism potentially mediated by the Keap-1/Nrf2/ARE pathway.

Nanomedicine in the Face of Parkinson's Disease: From Drug Delivery Systems to Nanozymes

The complexity and overall burden of Parkinson's disease (PD) require new pharmacological approaches to counteract the symptomatology while reducing the progressive neurodegeneration of affected dopaminergic neurons. Since the pathophysiological signature of PD is characterized by the loss of physiological levels of dopamine (DA) and the misfolding and aggregation of the alpha-synuclein (α-syn) protein, new proposals seek to restore the lost DA and inhibit the progressive damage derived from pathological α-syn and its impact in terms of oxidative stress. In this line, nanomedicine (the medical application of nanotechnology) has achieved significant advances in the development of nanocarriers capable of transporting and delivering basal state DA in a controlled manner in the tissues of interest, as well as highly selective catalytic nanostructures with enzyme-like properties for the elimination of reactive oxygen species (responsible for oxidative stress) and the proteolysis of misfolded proteins. Although some of these proposals remain in their early stages, the deepening of our knowledge concerning the pathological processes of PD and the advances in nanomedicine could endow for the development of potential treatments for this still incurable condition. Therefore, in this paper, we offer: (i) a brief summary of the most recent findings concerning the physiology of motor regulation and (ii) the molecular neuropathological processes associated with PD, together with (iii) a recapitulation of the current progress in controlled DA release by nanocarriers and (iv) the design of nanozymes, catalytic nanostructures with oxidoreductase-, chaperon, and protease-like properties. Finally, we conclude by describing the prospects and knowledge gaps to overcome and consider as research into nanotherapies for PD continues, especially when clinical translations take place.

The Stability and Anti-Angiogenic Properties of Titanium Dioxide Nanoparticles (TiO2NPs) Using Caco-2 Cells

Titanium dioxide nanoparticles (TiO₂NPs) are found in a wide range of products such as sunscreen, paints, toothpaste and cosmetics due to their white pigment and high refractive index. These wide-ranging applications could result in direct or indirect exposure of these NPs to humans and the environment. Accordingly, conflicting levels of toxicity has been associated with these NPs. Therefore, the risk associated with these reports and for TiO₂NPs produced using varying methodologies should be measured. This study aimed to investigate the effects of various media on TiO₂NP properties (hydrodynamic size and zeta potential) and the effects of TiO₂NP exposure on human colorectal adenocarcinoma (Caco-2) epithelial cell viability, inflammatory and cell stress biomarkers and angiogenesis proteome profiles. The NPs increased in size over time in the various media, while zeta potentials were stable. TiO₂NPs also induced cell stress biomarkers, which could be attributed to the NPs not being cytotoxic. Consequently, TiO₂NP exposure had no effects on the level of inflammatory biomarkers produced by Caco-2. TiO₂NPs expressed some anti-angiogenic properties when exposed to the no-observed-adverse-effect level and requires further in-depth investigation.

Phytochemical: a treatment option for heavy metal induced neurotoxicity

Heavy metals are known to be carcinogenic, mutagenic, and teratogenic. Some heavy metals are necessary while present in the growing medium in moderate concentrations known to be essential heavy metals as they required for the body functioning as a nutrient. But there are some unwanted metals and are also toxic to the environment and create a harmful impact on the body, which termed to be non-essential heavy metals. Upon exposure, the heavy metals decrease the major antioxidants of cells and enzymes with the thiol group and affect cell division, proliferation, and apoptosis. It interacts with the DNA repair mechanism and initiates the production of reactive oxygen species (ROS). It subsequently binds to the mitochondria and may inhibit respiratory and oxidative phosphorylation in even low concentrations. This mechanism leads to damage antioxidant repair mechanism of neuronal cells and turns into neurotoxicity. Now, phytochemicals have led to good practices in the health system. Phytochemicals that are present in the fruits and herbs can preserve upon free radical damage. Thus, this review paper summarized various phytochemicals which can be utilized as a treatment option to reverse the effect of the toxicity caused by the ingestion of heavy metals in our body through various environmental or lifestyles ways.

Nanoparticle-based toxicity in perishable vegetable crops: Molecular insights, impact on human health and mitigation strategies for sustainable cultivation

With the advancement of nanotechnology, the use of nanoparticles (NPs) and nanomaterials (NMs) in agriculture including perishable vegetable crops cultivation has been increased significantly. NPs/NMs positively affect plant growth and development, seed germination, plant stress management, and postharvest handling of fruits and vegetables. However, these NPs sometimes cause toxicity in plants by oxidative stress and excess reactive oxygen species production that affect cellular biomolecules resulting in imbalanced biological and metabolic processes in plants. Therefore, information about the mechanism underlying interactions of NPs with plants is important for the understanding of various physiological and biochemical responses of plants, evaluating phytotoxicity, and developing mitigation strategies for vegetable crops cultivation. To address this, recent morpho-physiological, biochemical and molecular insights of nanotoxicity in the vegetable crops have been discussed in this review. Further, factors affecting the nanotoxicity in vegetables and mitigation strategies for sustainable cultivation have been reviewed. Moreover, the bioaccumulation and biomagnification of NPs and associated phytotoxicity can cause serious effects on human health which has also been summarized. The review also highlights the use of advanced omics approaches and interdisciplinary tools for understanding the nanotoxicity and their possible use for mitigating phytotoxicity.

Food grade titanium dioxide accumulation leads to cellular alterations in colon cells after removal of a 24-hour exposure

Titanium dioxide food grade (E171) is one of the most used food additives containing nanoparticles. Recently, the European Food Safety Authority indicated that E171 could no longer be considered safe as a food additive due to the possibility of it being genotoxic and there is evidence that E171 administration exacerbates colon tumor formation in murine models. However, less is known about the effects of E171 accumulation once the exposure stopped, then we hypothesized that toxic effects could be detected even after E171 removal. Therefore, we investigated the effects of E171 exposure after being removed from colon cell cultures. Human colon cancer cell line (HCT116) was exposed to 0, 1, 10 and 50 μg/cm² of E171. Our results showed that in the absence of cytotoxicity, E171 was accumulated in the cells after 24 of exposure, increasing granularity and reactive oxygen species, inducing alterations in the molecular pattern of nucleic acids and lipids, and causing nuclei enlargement, DNA damage and tubulin depolymerization. After the removal of E171, colon cells were cultured for 48 h more hours to analyze the ability to restore the previously detected alterations. As we hypothesized, the removal of E171 was unable to revert the alterations found after 24 h of exposure in colon cells. In conclusion, exposure to E171 causes alterations that cannot be reverted after 48 h if E171 is removed from colon cells.

TGF-β1/SMADs signaling involved in alleviating inflammation induced by nanoparticulate titanium dioxide in BV2 cells

There are increasing safety concerns accompanying the widespread use of nanoparticulate titanium dioxide (nano-TiO₂). It has been demonstrated that nano-TiO₂ can cross the blood-brain barrier and enter the brain, causing damage to the nervous system, consisting mainly of neuroinflammation and neuronal apoptosis. Several studies have linked the TGF-β1/SMADs signaling to the development of inflammatory response in various organs. However, no studies have connected the induction of microglial inflammation by nano-TiO₂ to this signaling. Therefore, this study aimed to investigate the role of TGF-β1/SMADs signaling in microglia inflammatory response induced by nano-TiO₂. The results showed that nano-TiO₂ increased the secretions of pro-inflammatory cytokines (IL-1α, IL-6, and TNF-α) and decreased the expressions of TGF-β1 and SMAD1/2/3 proteins in BV2 cells. When TGF-β1/SMADs signaling was inhibited, the inflammatory effect induced by nano-TiO₂ increased, suggesting a suppressive effect of this signaling on the inflammation. In addition, exogenous TGF-β1 upregulated the expressions of TGF-β1 and SMADs1/2/3 proteins as well as decreased the secretions of pro-inflammatory cytokines (IL-1α, IL-6, and TNF-α) compared to BV2 cells treated with only nano-TiO₂. Our results suggest that nano-TiO₂ may inhibit the TGF-β1/SMADs signaling by suppressing the intracellular secretion of active TGF-β1, leading to microglial activation and the induction or exacerbation of inflammatory responses.

Metal Nanoparticles as Novel Antifungal Agents for Sustainable Agriculture: Current Advances and Future Directions

The use of metal nanoparticles is considered a good alternative to control phytopathogenic fungi in agriculture. To date, numerous metal nanoparticles (e.g., Ag, Cu, Se, Ni, Mg, and Fe) have been synthesized and used as potential antifungal agents. Therefore, this proposal presents a critical and detailed review of the use of these nanoparticles to control phytopathogenic fungi. Ag nanoparticles have been the most investigated nanoparticles due to their good antifungal activities, followed by Cu nanoparticles. It was also found that other metal nanoparticles have been investigated as antifungal agents, such as Se, Ni, Mg, Pd, and Fe, showing prominent results. Different synthesis methods have been used to produce these nanoparticles with different shapes and sizes, which have shown outstanding antifungal activities. This review shows the success of the use of metal nanoparticles to control phytopathogenic fungi in agriculture.

Influence of Titanium Dioxide Nanoparticles on Human Health and the Environment

Nanotechnology has enabled tremendous breakthroughs in the development of materials and, nowadays, is well established in various economic fields. Among the various nanomaterials, TiO₂ nanoparticles (NPs) occupy a special position, as they are distinguished by their high availability, high photocatalytic activity, and favorable price, which make them useful in the production of paints, plastics, paper, cosmetics, food, furniture, etc. In textiles, TiO₂ NPs are widely used in chemical finishing processes to impart various protective functional properties to the fibers for the production of high-tech textile products with high added value. Such applications contribute to the overall consumption of TiO₂ NPs, which gives rise to reasonable considerations about the impact of TiO₂ NPs on human health and the environment, and debates regarding whether the extent of the benefits gained from the use of TiO₂ NPs justifies the potential risks. In this study, different TiO₂ NPs exposure modes are discussed, and their toxicity mechanisms—evaluated in various in vitro and in vivo studies—are briefly described, considering the molecular interactions with human health and the environment. In addition, in the conclusion of this study, the toxicity and biocompatibility of TiO₂ NPs are discussed, along with relevant risk management strategies.

Exogenous Applications of Bio-fabricated Silver Nanoparticles to Improve Biochemical, Antioxidant, Fatty Acid and Secondary Metabolite Contents of Sunflower

The present study involved the bio-fabrication of silver nanoparticles (AgNPs) by using the Euphorbia helioscopia L. leaves aqueous extract to improve the production of secondary metabolites in industrially important sunflower (Helianthus annuus L.) plants. Phyto-fabrication of AgNPs was confirmed by using spectrophotometry, SEM imaging and X-ray diffraction analysis. The morphological and optical characterization manifested that the AgNPs are crystalline and exist in the size range of 30-100 nm. Various concentrations (10, 20, 40, 60, 80 and 100 mg/L) of AgNPs were applied in combinations on sunflower seeds and crop plants. The effects of biosynthesized AgNPs were evaluated for agro-morphological parameters (plant height, flowering initiation and seed weight), biochemical metabolites (chlorophyll, proline, soluble sugar, amino acid and protein contents) and enzymatic activities (superoxide dismutase and ascorbate peroxidase) in sunflower and 60 mg/L concentration of AgNPs on sunflower seeds and foliar sprays on plants in combination were found to be effective to elicit biochemical modifications to improve secondary metabolites. It was also observed experimentally that 60 mg/L concentration of AgNPs improved the biochemical, fatty acid and enzymatic attributes of sunflower plants, which in turn improved the plant agro-morphological parameters. Near-infrared spectroscopic analysis results confirmed the improvement in the seed quality, oil contents and fatty acid composition (palmitic acid, oleic acid and linoleic acid) after the applications of AgNPs. The findings of the present investigation confirm the exogenous applications of bio-fabricated AgNPs in combinations on seeds and plants to improve the plant yield, seed quality and secondary metabolite contents of the sunflower plants.

Therapeutic potential of biogenic titanium dioxide nanoparticles: a review on mechanistic approaches

Biogenic titanium dioxide nanoparticles have unique size, shape and biochemical functional corona that embellish them with the potential to perform therapeutic actions such as anticancer, antimicrobial, antioxidant, larvicidal and photocatalysis by adopting various mechanistic or physiological approaches at the molecular level. We have provided a detailed overview of some of these physiological mechanisms, including disruption of the electron transport chain, DNA fragmentation, mitochondrial damage, induction of apoptosis, disorganization of the plasma membrane, inhibition of ATP synthase activity, suspension of cellular signaling pathways and inhibition of enzymatic activity. The biogenic synthesis of customized titanium dioxide nanoparticles has future application potentials to do breakthroughs in the pharmaceutical sectors to advance precision medicine and to better explain the disease prognosis and treatment strategies.

Novel insights into biodegradation, interaction, internalization and impacts of high-aspect-ratio TiO2 nanomaterials: A systematic in vivo study using Drosophila melanogaster

The elongated nature of the high-aspect-ratio nanomaterials (NMs) can help us to obtain valuable information on its biodegradation, physical interaction with target-cells, and internalization. Three different length nano-titanium have been studied using Drosophila, TEM, and different biological markers. Nano-titanium, regardless of its shape, was eroded and degraded just entering the gut lumen of the larvae. Results showed that the distinguished shape of nanowires helps to understand the interactions of NMs with the intestinal barrier. The peritrophic membrane, as the first defense line of the intestinal barrier, succeeded in the reservation of NMs, though the perpendicular particles of nanowires stabbing it, making pores, and permitting their translocation into intestinal cells. On the other side, the exposure to TiO₂NPs did not decrease egg-to-adult viability, but all its different shapes, especially nanowires, mediated a wide molecular response including changes of expression in genes involved in stress, antioxidant, repair, and physical interaction responses. All these changes concerning their ability to elevate ROS levels ultimately led to potential genotoxicity. So, the high aspect ratio NMs are efficient in understanding the outstanding issues of NMs exposure, but at the same time could induce genotoxic impact rather than the low aspect ones.

Changing the morphology of one-dimensional titanate nanostructures affects its tissue distribution and toxicity

The present research investigated the impact of the morphology change of titanate (TiO₂) nanostructures on its tissue distribution and toxicity. The TiO₂ nanotubes, rods, and ribbons were synthesized by the hydrothermal technique, and the morphology was adjusted by alteration of the hydrothermal duration time. The characterization techniques were X-ray diffraction, high-resolution transmission electron microscopy, dynamic light scattering, and the Brunauer-Emmett-Teller method for measuring the surface area. The intravenously administrated dose (5 mg/kg) was injected as a single dose for 1 day and consecutively for 42 days. The quantitative analysis of accumulated TiO₂ nanostructures in the liver, spleen, and the heart was performed using an inductively coupled plasma emission spectrometer, and the organs' toxicity was estimated by histopathological analysis. The prepared nanostructures exhibited differences in morphology, crystallinity, size distribution, surface area, zeta potential, and aspect ratio. The results revealed a tissue distribution difference between the liver, spleen, and heart of these nanostructures, the distribution order was the liver, spleen, and the heart for all TiO₂ nanostructures. The toxicity was induced with different degrees. The nanotubes were the most harmful among the three formats. In summary, changes in the morphology of the TiO₂ nanostructures change its distribution and toxicity.

Targeted sonodynamic destruction of glioblastoma cells using antibody-titanium dioxide nanoparticle conjugates

Aim: We present data on sonodynamic therapy (SDT) against glioblastoma cells utilizing titanium dioxide (TiO₂) nanoparticles conjugated to anti-EGFR antibody. Materials & methods: TiO₂ nanoparticles were bound to anti-EGFR antibody to form antibody-nanoparticle conjugates (ANCs), then characterized by x-ray photoelectron spectroscopy and transmission electron microscopy. Cells underwent ultrasound and assessment on viability, reactive oxygen species and apoptosis were performed. Results: X-ray photoelectron spectroscopy analysis revealed the formation of an ANC. Transmission electron microscopy showed internalization of the ANCs by glioblastoma cells. With SDT, cell viabilities were reduced in the presence of ANCs, reactive oxygen species production was formed, but minimal effect on apoptosis was seen. Conclusion: For the first time, an ANC can be used with SDT to kill glioblastoma cells.

In Vitro Interactions of TiO2 Nanoparticles with Earthworm Coelomocytes: Immunotoxicity Assessment

Titanium dioxide nanoparticles (TiO₂ NPs) are manufactured worldwide. Once they arrive in the soil environment, they can endanger living organisms. Hence, monitoring and assessing the effects of these nanoparticles is required. We focus on the Eisenia andrei earthworm immune cells exposed to sublethal concentrations of TiO₂ NPs (1, 10, and 100 µg/mL) for 2, 6, and 24 h. TiO₂ NPs at all concentrations did not affect cell viability. Further, TiO₂ NPs did not cause changes in reactive oxygen species (ROS) production, malondialdehyde (MDA) production, and phagocytic activity. Similarly, they did not elicit DNA damage. Overall, we did not detect any toxic effects of TiO₂ NPs at the cellular level. At the gene expression level, slight changes were detected. Metallothionein, fetidin/lysenin, lumbricin and MEK kinase I were upregulated in coelomocytes after exposure to 10 µg/mL TiO₂ NPs for 6 h. Antioxidant enzyme expression was similar in exposed and control cells. TiO₂ NPs were detected on coelomocyte membranes. However, our results do not show any strong effects of these nanoparticles on coelomocytes at both the cellular and molecular levels.

Molecular mechanism of mice gastric oxidative damage induced by nanoparticulate titanium dioxide

Background

Nanoparticulate titanium dioxide (Nano-TiO₂) has been widely used in food industry, and it has been demonstrated to have adverse effects on mice and human stomach, but its mechanism is rarely concerned. The aim of this study is to determine the effects of nano-TiO₂ on the stomach and confirm the role of oxidative stress and apoptosis in the mice gastric damage caused by nano-TiO₂, as well as its molecular mechanisms.

Methods

Mice were continuously exposed to nano-TiO₂ with 1.25, 2.5 and 5 mg/kg bw by intragastric administration for 9 months in the present study. The ultrastructure, levels of reactive oxygen species (ROS) and peroxides, activities of antioxidant enzymes and mitochondria-related enzymes, ATP contents as well as apoptosis-related factors expression in mice stomach were examined.

Results

Oxidative stress, apoptosis and nano-TiO₂ aggregation were found in gastric mucosal smooth muscle cells after nano-TiO₂ exposure. Nano-TiO₂ exposure also resulted in the over-production of ROS and peroxides, decrease of ATP production and activities of antioxidant enzymes and mitochondria-related ATPases, upregulation of apoptosis-related factors including γH2AX, Cyt c, caspase 3, and p-JNK expression, and down-regulation of Bcl-2 expression in mice stomach.

Conclusions

The gastric toxicity of mice induced by chronic exposure to low dose nano-TiO₂ may be associated with oxidative stress and mitochondria-mediated apoptosis in mice.

Toxicological Consequences of Titanium Dioxide Nanoparticles (TiO2NPs) and Their Jeopardy to Human Population

Titanium dioxide nanoparticles (TiO₂ NPs) are the most produced nanomaterial for food additives, pigments, photocatalysis, and personal care products. These nanomaterials are at the forefront of rapidly developing indispensable nanotechnology. In all these nanomaterials, titanium dioxide (TiO₂) is the most common nanomaterial which is being synthesized for many years. These nanoparticles of TiO₂ are widely used at the commercial level, especially in cosmetic industries. High usage in such a way has increased the toxicological consequences of the human population. Several studies have shown that TiO₂ NPs accumulated after oral exposure or inhalation in the alimentary canal, lungs, heart, liver, spleen, cardiac muscle, and kidneys. Additionally, in mice and rats, they disturb glucose and lipid homeostasis. Moreover, TiO₂ nanoparticles primarily cause adverse reactions by inducing oxidative stress that leads to cell damage, inflammation, genotoxicity, and adverse immune responses. The form and level of destruction are strongly based on the physical and chemical properties of TiO₂ nanoparticles, which administer their reactivity and bioavailability. Studies give indications that TiO₂ NPs cause both DNA strand breaks and chromosomal damages. The effects of genotoxicity do not depend only on particle surface changes, size, and exposure route, but also relies on the duration of exposure. Most of these effects may be because of a very high dose of TiO₂ NPs. Despite increased production and use, epidemiological data for TiO₂ NPs is still missing. This review discusses previous research regarding the impact of TiO₂ NP toxicity on human health and highlights areas that require further understanding in concern of jeopardy to the human population. This review is important to point out areas where extensive research is needed; thus, their possible impact on individual health should be investigated in more details.

Nano-scaled materials may induce severe neurotoxicity upon chronic exposure to brain tissues: A critical appraisal and recent updates on predisposing factors, underlying mechanism, and future prospects

Owing to their tremendous potential, the inference of nano-scaled materials has revolutionized many fields including the medicine and health, particularly for development of various types of targeted drug delivery devices for early prognosis and successful treatment of various diseases, including the brain disorders. Owing to their unique characteristic features, a variety of nanomaterials (particularly, ultra-fine particles (UFPs) have shown tremendous success in achieving the prognostic and therapeutic goals for early prognosis and treatment of various brain maladies such as Alzheimer's disease, Parkinson's disease, brain lymphomas, and other ailments. However, serious attention is needful due to innumerable after-effects of the nanomaterials. Despite their immense contribution in optimizing the prognostic and therapeutic modalities, biological interaction of nanomaterials with various body tissues may produce severe nanotoxicity of different organs including the heart, liver, kidney, lungs, immune system, gastro-intestinal system, skin as well as nervous system. However, in this review, we have primarily focused on nanomaterials-induced neurotoxicity of the brain. Following their translocation into different regions of the brain, nanomaterials may induce neurotoxicity through multiple mechanisms including the oxidative stress, DNA damage, lysosomal dysfunction, inflammatory cascade, apoptosis, genotoxicity, and ultimately necrosis of neuronal cells. Our findings indicated that rigorous toxicological evaluations must be carried out prior to clinical translation of nanomaterials-based formulations to avoid serious neurotoxic complications, which may further lead to develop various neuro-degenerative disorders.

Presence of Titanium and Toxic Effects Observed in Rat Lungs, Kidneys, and Central Nervous System in vivo and in Cultured Astrocytes in vitro on Exposure by Titanium Dioxide Nanorods

Background

Non-spherical titanium dioxide (TiO₂) nanoparticles have been increasingly applied in various biomedical and technological fields. Their toxicological characterization is, however, less complete than that of roundish nanoparticles.

Materials and Methods

Anatase form TiO₂ nanorods, ca. 15x65 nm in size, were applied to cultured astrocytes in vitro and to the airways of young adult Wistar rats in vivo in 5, 10, and 8 mg/kg BW dose for altogether 28 days. Presence of nanorods and cellular damage was investigated in the astrocytes and in rat lungs and kidneys. Functional damage of the nervous system was studied by electrophysiological methods.

Results

The treated astrocytes showed loss of viability without detectable apoptosis. In rats, TiO₂ nanorods applied to the airways reached the blood and various organs including the lungs, kidneys, and the central nervous system. In lung and kidney samples, nanorods were observed within (partly damaged) phagolysosomes and attached to organelles, and apoptotic cell death was also detected. In cortical and peripheral electrophysiological activity, alterations corresponding to energy shortage (resulting possibly from mitochondrial damage) and astrocytic dysfunction were detected. Local titanium levels and relative weight of the investigated organs, apoptotic cell death in the lungs and kidneys, and changes in the central and peripheral nervous activity were mostly proportional to the applied doses, and viability loss of the cultured astrocytes was also dose-dependent, suggesting causal relationship of treatments and effects.

Conclusion

Based on localization of the visualized nanorods, on neuro-functional changes, and on literature data, the toxic mechanism involved mitochondrial damage, oxidative stress, and apoptotic cell death. These indicate potential human toxicity and occupational risk in case of exposure to rod-shaped TiO₂ nanoparticles.

Transfer and Transcriptomic Profiling in Liver and Brain of European Eels (Anguilla anguilla) After Diet-borne Exposure to Gold Nanoparticles

A nanometric revolution is underway, promising technical innovations in a wide range of applications and leading to a potential boost in environmental discharges. The propensity of nanoparticles (NPs) to be transferred throughout trophic chains and to generate toxicity was mainly assessed in primary consumers, whereas a lack of knowledge for higher trophic levels persists. The present study focused on a predatory fish, the European eel (Anguilla anguilla) exposed to gold NPs (AuNPs; 10 nm, polyethylene glycol-coated) for 21 d at 3 concentration levels in food: 0 (NP0), 1 (NP1), and 10 (NP10) mg Au kg^-1 . Transfer was assessed by Au quantification in eel tissues, and transcriptomic responses in the liver and brain were revealed by a high-throughput RNA-sequencing approach. Eels fed at NP10 presented an erratic feeding behavior, whereas Au quantification only indicated transfer to intestine and kidney of NP1-exposed eels. Sequencing of RNA was performed in NP0 and NP1 eels. A total of 258 genes and 156 genes were significantly differentially transcribed in response to AuNP trophic exposure in the liver and brain, respectively. Enrichment analysis highlighted modifications in the immune system-related processes in the liver. In addition, results pointed out a shared response of both organs regarding 13 genes, most of them being involved in immune functions. This finding may shed light on the mode of action and toxicity of AuNPs in fish. Environ Toxicol Chem 2020;39:2450-2461. © 2020 SETAC.

A study of Titanium and Magnesium particle-induced oxidative stress and toxicity to human osteoblasts

Hybrid implants combine both Titanium (Ti) and Magnesium (Mg) are prevalent nowadays. The long-term implications of Ti and Mg implants within the human body are not yet fully understood. Many implant failure cases due to inflammation, allergic responses, and aspect loosening have been reported frequently. Particles generated through daily wear and tear of implants may worsen the situation by causing acute complications. An in-depth understanding of the behavior of metal particles with human osteoblasts is necessary. In this study, a novel and systematic attempt was made to understand the effects of different concentrations of Ti and Mg particles to the osteoblastic SAOS2 cell: toxicity, alterations to mitochondria, and changes to the specific gene and protein expression. Ti particles were found toxic to SAOS2 cells at different dosages, while Mg particles at lower concentrations could improve cell viability. To understand this phenomenon better, we have measured cellular reactive oxygen species (ROS) production and cell apoptosis & necrosis percentage. We also have checked the mitochondrial structure with transmission electron microscope (TEM), and mitochondrial function using Tetramethyl rhodamine, ethyl ester staining (TMRE). NDUFB6, SDHC, and ATP5F1 were the essential mitochondrial genes involved in the ROS production and ATP production. Immunocytochemistry (ICC) and real-time polymerase chain reaction (qPCR) were implemented to check the regulations of these related genes.

Moringa seed extract alleviates titanium oxide nanoparticles (TiO2-NPs)-induced cerebral oxidative damage, and increases cerebral mitochondrial viability

To investigate the influence of Moringa seed extract (MSE) on the cerebral Nrf2/NQO1 signaling in TiO₂-NPs-induced brain damage, 80 male albino rats were divided into four groups (n = 20); group I was used as a control, group II received TiO₂-NPs (500 mg/kg b.w/day orally) for 14 days, group III received MSE (100 mg/kg b.w/day orally) for 30 days, and group IV received MSE an hour before TiO₂-NPs administration with the same doses as before. Administration of TiO₂-NPs was started on the 17th day for both groups (II) and (IV). Administration of MSE significantly increased the cerebral mitochondrial viability and Nrf2 level with a simultaneous increase of NQO1 mRNA expression. This designates a powerful antioxidant effect of MSE which is indicated by a significant reduction of INOS expression, MDA, TOS, OSI levels, and DNA fragmentation % with a significant increase of GSH concentration, SOD activities, and TAC. MSE possesses an anti-inflammatory effect by a significant reduction of IL-1β and TNF-α levels, and anti-apoptotic effect manifested by a significant reduction of caspase-3 and Fas levels. In harmonization, dopamine, serotonin concentrations, and acetylcholinesterase activities return back to normal as compared to control group. These results were confirmed by the histopathological features which were alleviated with MSE administration. In conclusion, Nrf2 plays a pivotal role in the mechanism of TiO₂-NPs cerebral toxicity and MSE as a Nrf2 activator can provide a powerful cerebroprotective effect, whereas MSE increased the Nrf2 expression and consequently restore the antioxidant activity of brain cells by increasing NQO1 gene expression and cerebral mitochondrial viability as well as inhibition of pro-inflammatory and apoptotic mediators.

Population Kinetics and Mechanistic Aspects of Saccharomyces cerevisiae Growth in Relation to Selenium Sulfide Nanoparticle Synthesis

Biosynthesis of nanoparticles (NPs) by microorganisms is a cost- and energy-effective approach. However, how the production of NPs affects the population of producing organism remains as an unresolved question. The present study aimed to evaluate the kinetics of Saccharomyces cerevisiae growth in relation to synthesis of selenium sulfide nanoparticles by using a population model. To this end, the population of S. cerevisiae cells was investigated in terms of colony forming units (CFU) in the presence of the substrate in different time points. Fluctuation of sulfite reductase (SiR) activity, expression of MET5 and MET10 genes, and concentrations of sulfite and selenium were evaluated to support the population findings. CFU values in the test groups were lower than those in the control counterparts. The rise and fall of the SiR activity and MET5 and MET10 gene expression conformed to the variations of CFU values. The rate of reduction in the selenium and sulfite concentrations tended to decrease over the time. In conclusion, the cells population was negatively and positively affected by selenium and sulfite concentrations, respectively. The indirect relationship of the selenium ions concentration in the path analysis revealed that the product, selenium sulfide nanoparticles, caused this drop in S. cerevisiae cells population.

The NADPH oxidase 4 protects vascular endothelial cells from copper oxide nanoparticles-induced oxidative stress and cell death

AIMS

Nanoparticles (NPs) exposure is associated with increased risk of cardiovascular diseases, but the underlying mechanism is still obscure. In this study, we investigated the role of NADPH oxidase 4 (NOX4) in copper oxide nanoparticles (CuONPs)-induced cytotoxicity in human umbilical vein endothelial cells (HUVECs).

MATERIALS AND METHODS

Morphology changes were examined under the microscope. Cell viability was determined by MTS assay and Calcein AM assay. Apoptosis and the levels of superoxide anion (O₂^-) and hydrogen peroxide (H₂O₂) were measured by fluorescence activated cell sorting (FACS). Oxidative stress was detected by assaying the levels of glutathione/glutathione disulfide (GSH/GSSG) and malondialdehyde (MDA). Protein expression levels were determined by western blotting.

KEY FINDINGS

We revealed that O₂^- rather than H₂O₂ was the major component of reactive oxygen species (ROS) in CuONPs-treated HUVECs. Meanwhile, CuONPs downregulated expression of O₂^--eliminating enzyme NOX4 both at mRNA and protein levels, but did not affect the expression of SOD2 and catalase. NOX4 knockdown caused more accumulation of O₂^-, and a further decrease of H₂O₂ in CuONPs-treated HUVECs, suggesting that NOX4 regulates the conversion of O₂^- to H₂O₂ in CuONPs-treated HUVECs. Furthermore, we revealed that NOX4 knockdown aggravated CuONPs-induced oxidative stress, characterized by a decrease of GSH/GSSG ratio, an increase of MDA level, and upregulation of HSPA5 and γH2AX. Finally, we showed that NOX4 knockdown exacerbated CuONPs-induced apoptotic cell death in HUVECs, indicating that NOX4 could protect ECs from CuONPs-induced cell death.

SIGNIFICANCE

Our study provides the evidence that NOX4 protects vascular endothelial cells from CuONPs-induced oxidative stress and cell death.

Titanium dioxide nanoparticles via oral exposure leads to adverse disturbance of gut microecology and locomotor activity in adult mice

Titanium dioxide nanoparticles (TiO₂NPs) have been widely used as food additives in daily life. However, the impact of oral intake of TiO₂NPs on the nervous system is largely unknown. In this study, 7-week-old mice were treated with either vehicle or TiO₂NPs suspension solution at 150 mg/kg by intragastric administration for 30 days. Our results demonstrated that oral exposure to TiO₂NPs resulted in aberrant excitement of enteric neurons, although unapparent pathological changes were observed in gut. We also found the richness and evenness of gut microbiota were remarkably decreased and the gut microbial community compositions were significantly changed in the TiO₂NP-treated group as compared with vehicle controls. Interestingly, oral exposure to TiO₂NPs was capable to induce the inhibitory effects on locomotor activity, but it did not lead to significant change on the spatial learning and memory ability. We further revealed the mechanism that TiO₂NPs could specifically cause locomotor dysfunction by elevating the excitement of enteric neuron, which might spread to brain via gut-brain communication by vagal pathway. However, inflammation response, enteric neurotransmitter 5-HT and major gut peptides might not be involved in this pathological process. Together, these findings provide valuable insights into the novel mechanism of TiO₂NP-induced neurotoxicity. Understanding the microbiota-gut-brain axis will provide the foundation for potential therapeutic or prevention approaches against TiO₂NP-induced gut and brain-related disorders.

Mitochondrial toxicity of nanomaterials

In recent years, nanomaterials have been widely applied in electronics, food, biomedicine and other fields, resulting in increased human exposure and consequent research focus on their biological and toxic effects. Mitochondria, the main target organelle for nanomaterials (NM), play a critical role in their toxic activities. Several studies to date have shown that nanomaterials cause alterations in mitochondrial morphology, mitochondrial membrane potential, opening of the mitochondrial permeability transition pore (MPTP) and mitochondrial respiratory function, and promote cytochrome C release. An earlier mitochondrial toxicity study of NMs additionally reported induction of mitochondrial dynamic changes. Here, we have reviewed the mitochondrial toxicity of NMs and provided a scientific basis for the contribution of mitochondria to the toxicological effects of different NMs along with approaches to reduce mitochondrial and, consequently, overall toxicity of NMs.

Titanium dioxide nanoparticles promote oxidative stress, autophagy and reduce NLRP3 in primary rat astrocytes

Titanium dioxide nanoparticles (TiO₂-NPs) are widely used in the food industry, cosmetics, personal care and paints among others. Through occupational exposure and daily consumption, and because of their small size, TiO₂-NPs can enter the body through different routes such as oral, dermal and inhalation, and accumulate in multiple organs including the brain. TiO₂-NPs cause severe damage to many cell types, however their effects in the central nervous system remain largely unexplored. Therefore, in the present study we determined the cytotoxic effect of TiO₂-NPs on rat astrocytes. We tested the oxidant properties of TiO₂-NPs through DTT depletion, and measured oxidative stress-induced damage in mitochondria, through oxidation of 2,7-dichlorodihydrofluorescein diacetate (H₂DCFDA) and loss of mitochondrial membrane potential (ΔΨm) with Mitotracker Green FM. We further examined oxidative stress-derived responses such as IκB-α degradation by Western Blot, NF-κB translocation by EMSA, autophagy induction by LC3-II levels, and expression of the inflammasome protein NLRP3. TiO₂-NPs showed high oxidant properties and induced strong oxidative stress in astrocytes following their internalization, causing mitochondrial damage detected by ΔΨm loss. Responses against oxidative damage such as NF-κB translocation and autophagy were induced and NLRP3 protein expression was downregulated, indicating lower inflammasome-mediated responses in astrocytes. These results support TiO₂-NPs cytotoxicity in astrocytes, cells that play key roles in neuronal homeostasis and their dysfunction can lead to neurological disorders including cognitive impairment and memory loss.

A method for the separation of TiO2 nanoparticles from Water through encapsulation with lecithin liposomes followed by adsorption onto poly(L-lysine) coated glass surfaces

Increasing use of nanomaterials in the consumer and pharmaceutical industries has led to emerging contamination by released nanoparticles in wastewater and drinking water, causing major concerns for public health. Titanium dioxide (TiO₂) nanoparticles are one of the major nanoparticles of growing concern with a strong need for efficient removal. In this work, removal of TiO₂ nanoparticles from water was investigated by first coating with polydopamine (PDA) and then encapsulating within lecithin liposomes for adsorption onto poly-l-lysine (PLL) coated glass surfaces. The PLL coating was confirmed using atomic force microscopy, with a thickness of 30 nm. An average percent removal of 58% with a standard deviation of 18% was obtained for concentrations ranging from 5 mg/L to 125 mg/L following capture experiments. This method provides a promising solution to alleviate the potential health hazard caused by TiO₂ nanoparticles. It is minimally affected by such water quality variables as alkalinity, ionic strength and humic acid. No coagulation, flocculation and sedimentation stages are necessary.

Effects of Titanium Dioxide Nanoparticles Exposure on Human Health-a Review

Recently, an increased interest in nanotechnology applications can be observed in various fields (medicine, materials science, pharmacy, environmental protection, agriculture etc.). Due to an increasing scope of applications, the exposure of humans to nanoparticles (NPs) is inevitable. A number of studies revealed that after inhalation or oral exposure, NPs accumulate in, among other places, the lungs, alimentary tract, liver, heart, spleen, kidneys and cardiac muscle. In addition, they disturb glucose and lipid homeostasis in mice and rats. In a wide group of nanoparticles currently used on an industrial scale, titanium dioxide nanoparticles-TiO₂ NPs-are particularly popular. Due to their white colour, TiO₂ NPs are commonly used as a food additive (E 171). The possible risk to health after consuming food containing nanoparticles has been poorly explored but it is supposed that the toxicity of nanoparticles depends on their size, morphology, rate of migration and amount consumed. Scientific databases inform that TiO₂ NPs can induce inflammation due to oxidative stress. They can also have a genotoxic effect leading to, among others, apoptosis or chromosomal instability. This paper gives a review of previous studies concerning the effects of exposure to TiO₂ NPs on a living organism (human, animal). This information is necessary in order to demonstrate potential toxicity of inorganic nanoparticles on human health.

The mTOR/GCLc/GSH Pathway Mediates the Dose-Dependent Bidirectional Regulation of ROS Induced by TiO2NPs in Neurogenic Cells

Objective. The effect of TiO2NP exposure on the nervous system and the underlying mechanism remain unclear. The antioxidant effect of TiO2NPs at a low dose was newly found in our study, which was different from the effect at high dose. This study is aimed at exploring the mechanism underlying the antioxidant effects of TiO2NPs at low dose and the induction of ROS accumulation by TiO2NPs at high dose in neurogenic cell lines.Methods. We measured the changes in key molecules in the ROS regulation pathway by western blotting, flow cytometry, and commercial assay kits, and these key molecules were further evaluated to verify their interactions and roles using SH-SY5Y, U251, and SK-N-SH cell lines treated with TiO2NPs.Results. Our results showed that the weak antioxidant effect at low dose was caused by mTOR/GCLc-induced GSH overproduction and GSH-Px activity impairment. ROS accumulation at high dose was caused by a mTOR/GCLc-mediated decrease in GSH production, GSH-Px activity impairment, and dramatic ROS production. Furthermore, we found that the ROS species were mainly O2-⋅, and that SOD played a crucial role in reducing O2-⋅levels before the mTOR protein was activated.Conclusion. We revealed the mechanism underlying the bidirectional regulation of ROS induced by TiO2NPs at different doses in neurogenic cell lines. Our study emphasized the potential neurotoxic effects of NPs at low dose, which should arouse concern about their safety.

Exposure to Waterborne nTiO2 Reduces Fertilization Success and Increases Polyspermy in a Bivalve Mollusc: A Threat to Population Recruitment

Fertilization success is crucial for the population recruitment of an organism. However, little is known about the threat of nanoparticles (NPs) to the fertilization of broadcast spawners. Therefore, the effects of nTiO₂ on fertilization success, polyspermy rate, sperm velocity, gametic DNA damage, sperm-egg collision probability, gamete fusion, and oocyte ultrastructure were investigated in a broadcast spawning bivalve, Tegillarca granosa. The results obtained show that fertilization success significantly decreased, whereas polyspermy risk markedly increased upon nTiO₂ exposure. In addition, nTiO₂ exposure led to a significant reduction in sperm swimming velocity, which would subsequently constrain gamete collisions. In addition, nTiO₂ exposure resulted in a significant decline in gamete fusion per collision along with aggravated DNA damage in gametes. Furthermore, ultrastructural analysis illustrated the attachment of nTiO₂ to the oocyte surface, which subsequently resulted in microvillus disassociation and plasma membrane damage. In conclusion, the results obtained suggest a significant threat from NP pollution to the recruitment of broadcast spawning invertebrates.

Chitosan nanoparticles induced the antitumor effect in hepatocellular carcinoma cells by regulating ROS-mediated mitochondrial damage and endoplasmic reticulum stress

In recent years, numerous studies have confirmed the role of chitosan nanoparticles (CS NPs) as a promising drug delivery carrier for improving the efficiency of anticancer drug in the treatment of cancer. However, the possible biological effects of CS NPs on tumour cells and underlying mechanisms are still unclear. Recently, reactive oxygen species (ROS)-mediated cell apoptosis has been implicated in the regulation of cell death. In this study, we found that CS NPs induced the massive generation of ROS and resulted in apoptosis of hepatocellular carcinoma cells (SMMC-7721) through activating the mitochondrial pathway and endoplasmic reticulum stress. These results suggest an important role of ROS in CS NPs-induced cancer cell death.