A combined microRNA and proteome profiling to investigate the effect of ZnO nanoparticles on neuronal cells

Differentiated and mature neurons are more responsive to neurotoxicant exposure at both transcriptional and translational levels

SH-SY5Y human neuroblastoma cells have been extensively used as an in vitro model system in a diverse range of studies involving neurodevelopment, neurotoxicity, neurodegeneration, and neuronal ageing. Both naïve and differentiated phenotypes of SH-SY5Y cells are utilized to model human neurons under in vitro conditions. The process of differentiation causes extensive remodeling of neuronal cells at multiple omic levels, including the epigenome and proteome. In the present investigation, the miRNAome and proteome profiles of arsenic-treated naïve and differentiated SH-SY5Y cells were generated using the miRNA OpenArray technology and high-resolution mass spectrometry. Our findings demonstrated that differentiation dramatically affected the response of SH-SY5Y cells to toxicant exposure, as indicated by increased tolerance of differentiated cells against arsenic exposure compared to naïve cells in cell viability assay. Arsenic-exposed naïve and differentiated SH-SY5Y cells possess distinct miRNA and protein profiles with few similarities. Compared to naïve cells, differentiated cells have undergone higher deregulation in the expression of brain-enriched miRNAs and proteins and have shown a more drastic decrease in oxygen consumption rate, which is a measure of mitochondrial respiration after exposure to arsenic. Proteins identified in arsenic-treated differentiated SH-SY5Y cells were more enriched in pathways underlying multifactorial neurotoxic events. Additionally, more functional regulatory modules have been identified between the miRNAs and proteins differentially expressed in arsenic-treated differentiated SH-SY5Y cells relative to naïve cells. Collectively, our studies have shown that differentiated SH-SY5Y cells displayed alterations in the expression of a greater number of miRNAs and proteins following neurotoxicant exposure, indicating their higher responsivity.

Molecular mechanisms of zinc oxide nanoparticles neurotoxicity

Zinc oxide nanoparticles (ZnONPs) are widely used in industry and biomedicine. A growing body of evidence demonstrates that ZnONPs exposure may possess toxic effects to a variety of tissues, including brain. Therefore, the objective of the present review was to summarize existing evidence on neurotoxic effects of ZnONPs and discuss the underlying molecular mechanisms. The existing laboratory data demonstrate that both in laboratory rodents and other animals ZnONPs exposure results in a significant accumulation of Zn in brain and nervous tissues, especially following long-term exposure. As a result, overexposure to ZnONPs causes oxidative stress and cell death, both in neurons and glial cells, by induction of apoptosis, necrosis and ferroptosis. In addition, ZnONPs may induce neuroinflammation through the activation of nuclear factor kappa B (NF-κB), extracellular signal-regulated kinase (ERK), p38 mitogen-activated protein kinase (MAPK), and lipoxygenase (LOX) signaling pathways. ZnONPs exposure is associated with altered cholinergic, dopaminergic, serotoninergic, as well as glutamatergic and γ-aminobutyric acid (GABA)-ergic neurotransmission, thus contributing to impaired neuronal signal transduction. Cytoskeletal alterations, as well as impaired autophagy and mitophagy also contribute to ZnONPs-induced brain damage. It has been posited that some of the adverse effects of ZnONPs in brain are mediated by altered microRNA expression and dysregulation of gut-brain axis. Furthermore, in vivo studies have demonstrated that ZnONPs exposure induced anxiety, motor and cognitive deficits, as well as adverse neurodevelopmental outcome. At the same time, the relevance of ZnONPs-induced neurotoxicity and its contribution to pathogenesis of neurological diseases in humans are still unclear. Further studies aimed at estimation of hazards of ZnONPs to human brain health and the underlying molecular mechanisms are warranted.

Cytotoxic Potencies of Zinc Oxide Nanoforms in A549 and J774 Cells

Zinc oxide nanoparticles (NPs) are used in a wide range of consumer products and in biomedical applications, resulting in an increased production of these materials with potential for exposure, thus causing human health concerns. Although there are many reports on the size-related toxicity of ZnO NPs, the toxicity of different nanoforms of this chemical, toxicity mechanisms, and potency determinants need clarification to support health risk characterization. A set of well-characterized ZnO nanoforms (e.g., uncoated ca. 30, 45, and 53 nm; coated with silicon oil, stearic acid, and (3-aminopropyl) triethoxysilane) were screened for in vitro cytotoxicity in two cell types, human lung epithelial cells (A549), and mouse monocyte/macrophage (J774) cells. ZnO (bulk) and ZnCl2 served as reference particles. Cytotoxicity was examined 24 h post-exposure by measuring CTB (viability), ATP (energy metabolism), and %LDH released (membrane integrity). Cellular oxidative stress (GSH-GSSG) and secreted proteins (targeted multiplex assay) were analyzed. Zinc oxide nanoform type-, dose-, and cell type-specific cytotoxic responses were seen, along with cellular oxidative stress. Cell-secreted protein profiles suggested ZnO NP exposure-related perturbations in signaling pathways relevant to inflammation/cell injury and corresponding biological processes, namely reactive oxygen species generation and apoptosis/necrosis, for some nanoforms, consistent with cellular oxidative stress and ATP status. The size, surface area, agglomeration state and metal contents of these ZnO nanoforms appeared to be physicochemical determinants of particle potencies. These findings warrant further research on high-content "OMICs" to validate and resolve toxicity pathways related to exposure to nanoforms to advance health risk-assessment efforts and to inform on safer materials.

Toxicity of zinc oxide nanoparticles: Cellular and behavioural effects

Due to their extensive use, the release of zinc oxide nanoparticles (ZnO NP) into the environment is increasing and may lead to unintended risk to both human health and ecosystems. Access of ZnO NP to the brain has been demonstrated, so their potential toxicity on the nervous system is a matter of particular concern. Although evaluation of ZnO NP toxicity has been reported in several previous studies, the specific effects on the nervous system are not completely understood and, particularly, effects on genetic material and on organism behaviour are poorly addressed. We evaluated the potential toxic effects of ZnO NP in vitro and in vivo, and the role of zinc ions (Zn2+) in these effects. In vitro, the ability of ZnO NP to be internalized by A172 glial cells was verified, and the cytotoxic and genotoxic effects of ZnO NP or the released Zn2+ ions were addressed by means of vital dye exclusion and comet assay, respectively. In vivo, behavioural alterations were evaluated in zebrafish embryos using a total locomotion assay. ZnO NP induced decreases in viability of A172 cells after 24 h of exposure and genetic damage after 3 and 24 h. The involvement of the Zn2+ ions released from the NP in genotoxicity was confirmed. ZnO NP exposure also resulted in decreased locomotor activity of zebrafish embryos, with a clear role of released Zn2+ ions in this effect. These findings support the toxic potential of ZnO NP showing, for the first time, genetic effects on glial cells and proving the intervention of Zn2+ ions.

Proteomic-miRNA Biomics Profile Reveals 2D Cultures of Human iPSC-Derived Neural Progenitor Cells More Sensitive than 3D Spheroid System Against the Experimental Exposure to Arsenic

The iPSC-derived 3D models are considered to be a connective link between 2D culture and in vivo studies. However, the sensitivity of such 3D models is yet to be established. We assessed the sensitivity of the hiPSC-derived 3D spheroids against 2D cultures of neural progenitor cells. The sub-toxic dose of Sodium Arsenite (SA) was used to investigate the alterations in miRNA-proteins in both systems. Though SA exposure induced significant alterations in the proteins in both 2D and 3D systems, these proteins were uncommon except for 20 proteins. The number and magnitude of altered proteins were higher in the 2D system compared to 3D. The association of dysregulated miRNAs with the target proteins showed their involvement primarily in mitochondrial bioenergetics, oxidative and ER stress, transcription and translation mechanism, cytostructure, etc., in both culture systems. Further, the impact of dysregulated miRNAs and associated proteins on these functions and ultrastructural changes was compared in both culture systems. The ultrastructural studies revealed a similar pattern of mitochondrial damage, while the cellular bioenergetics studies confirm a significantly higher energy failure in the 2D system than to 3D. Such a higher magnitude of changes could be correlated with a higher amount of internalization of SA in 2D cultures than in 3D spheroids. Our findings demonstrate that a 2D culture system seems better responsive than a 3D spheroid system against SA exposure.

ZnO NPs induce miR-342-5p mediated ferroptosis of spermatocytes through the NF-κB pathway in mice

BACKGROUND

Zinc oxide nanoparticle (ZnO NP) is one of the metal nanomaterials with extensive use in many fields such as feed additive and textile, which is an emerging threat to human health due to widely distributed in the environment. Thus, there is an urgent need to understand the toxic effects associated with ZnO NPs. Although previous studies have found accumulation of ZnO NPs in testis, the molecular mechanism of ZnO NPs dominated a decline in male fertility have not been elucidated.

RESULTS

We reported that ZnO NPs exposure caused testicular dysfunction and identified spermatocytes as the primary damaged site induced by ZnO NPs. ZnO NPs led to the dysfunction of spermatocytes, including impaired cell proliferation and mitochondrial damage. In addition, we found that ZnO NPs induced ferroptosis of spermatocytes through the increase of intracellular chelatable iron content and lipid peroxidation level. Moreover, the transcriptome analysis of testis indicated that ZnO NPs weakened the expression of miR-342-5p, which can target Erc1 to block the NF-κB pathway. Eventually, ferroptosis of spermatocytes was ameliorated by suppressing the expression of Erc1.

CONCLUSIONS

The present study reveals a novel mechanism in that miR-342-5p targeted Erc1 to activate NF-κB signaling pathway is required for ZnO NPs-induced ferroptosis, and provide potential targets for further research on the prevention and treatment of male reproductive disorders related to ZnO NPs.

MicroRNA-29b-3p degenerates terminally differentiated dopaminergic SH-SY5Y cells by perturbation of mitochondrial functions

Mitochondrial dysfunction is the main cause of gradual deterioration of structure and function of neuronal cells, eventually resulting in neurodegeneration. Studies have revealed a complex interrelationship between neurotoxicant exposure, mitochondrial dysfunction, and neurodegenerative diseases. Alteration in the expression of microRNAs (miRNAs) has also been linked with disruption in mitochondrial homeostasis and bioenergetics. In our recent research (Cellular and Molecular Neurobiology (2023) https://doi.org/10.1007/s10571-023-01362-4), we have identified miR-29b-3p as one of the most significantly up-regulated miRNAs in the blood of Parkinson's patients. The findings of the present study revealed that neurotoxicants of two different natures, that is, arsenic or rotenone, dramatically increased miR-29b-3p expression (18.63-fold and 12.85-fold, respectively) in differentiated dopaminergic SH-SY5Y cells. This dysregulation of miR-29b-3p intricately modulated mitochondrial morphology, induced oxidative stress, and perturbed mitochondrial membrane potential, collectively contributing to the degeneration of dopaminergic cells. Additionally, using assays for mitochondrial bioenergetics in live and differentiated SH-SY5Y cells, a reduction in oxygen consumption rate (OCR), maximal respiration, basal respiration, and non-mitochondrial respiration was observed in cells transfected with mimics of miR-29b-3p. Inhibition of miR-29b-3p by transfecting inhibitor of miR-29b-3p prior to exposure to neurotoxicants significantly restored OCR and other respiration parameters. Furthermore, we observed that induction of miR-29b-3p activates neuronal apoptosis via sirtuin-1(SIRT-1)/YinYang-1(YY-1)/peroxisome proliferator-activated receptor-gamma coactivator-1alpha (PGC-1α)-regulated Bcl-2 interacting protein 3-like-dependent mechanism. Collectively, our studies have shown the role of miR-29b-3p in dysregulation of mitochondrial bioenergetics during degeneration of dopaminergic neurons via regulating SIRT-1/YY-1/PGC-1α axis.

Neurotoxic effects of heavy metal pollutants in the environment: Focusing on epigenetic mechanisms

The pollution of heavy metals (HMs) in the environment is a significant global environmental issue, characterized by its extensive distribution, severe contamination, and profound ecological impacts. Excessive exposure to heavy metal pollutants can damage the nervous system. However, the mechanisms underlying the neurotoxicity of most heavy metals are not completely understood. Epigenetics is defined as a heritable change in gene function that can influence gene and subsequent protein expression levels without altering the DNA sequence. Growing evidence indicates that heavy metals can induce neurotoxic effects by triggering epigenetic changes and disrupting the epigenome. Compared with genetic changes, epigenetic alterations are more easily reversible. Epigenetic reprogramming techniques, drugs, and certain nutrients targeting specific epigenetic mechanisms involved in gene expression regulation are emerging as potential preventive or therapeutic tools for diseases. Therefore, this review provides a comprehensive overview of epigenetic modifications encompassing DNA/RNA methylation, histone modifications, and non-coding RNAs in the nervous system, elucidating their association with various heavy metal exposures. These primarily include manganese (Mn), mercury (Hg), lead (Pb), cobalt (Co), cadmium (Cd), nickel (Ni), sliver (Ag), toxic metalloids arsenic (As), and etc. The potential epigenetic mechanisms in the etiology, precision prevention, and target therapy of various neurodevelopmental disorders or different neurodegenerative diseases are emphasized. In addition, the current gaps in research and future areas of study are discussed. From a perspective on epigenetics, this review offers novel insights for prevention and treatment of neurotoxicity induced by heavy metal pollutants.

A protein-miRNA biomic analysis approach to explore neuroprotective potential of nobiletin in human neural progenitor cells (hNPCs)

Chemical-induced neurotoxicity is increasingly recognized to accelerate the development of neurodegenerative disorders (NDs), which pose an increasing health burden to society. Attempts are being made to develop drugs that can cross the blood-brain barrier and have minimal or no side effects. Nobiletin (NOB), a polymethoxylated flavonoid with anti-oxidative and anti-inflammatory effects, has been demonstrated to be a promising compound to treat a variety of NDs. Here, we investigated the potential role of NOB in sodium arsenate (NA)-induced deregulated miRNAs and target proteins in human neural progenitor cells (hNPCs). The proteomics and microRNA (miRNA) profiling was done for different groups, namely, unexposed control, NA-exposed, NA + NOB, and NOB groups. Following the correlation analysis between deregulated miRNAs and target proteins, RT-PCR analysis was used to validate the selected genes. The proteomic analysis showed that significantly deregulated proteins were associated with neurodegeneration pathways, response to oxidative stress, RNA processing, DNA repair, and apoptotic process following exposure to NA. The OpenArray analysis confirmed that NA exposure significantly altered miRNAs that regulate P53 signaling, Wnt signaling, cell death, and cell cycle pathways. The RT-PCR validation studies concur with proteomic data as marker genes associated with autophagy and apoptosis (HO-1, SQSTM1, LC-3, Cas3, Apaf1, HSP70, and SNCA1) were altered following NA exposure. It was observed that the treatment of NOB significantly restored the deregulated miRNAs and proteins to their basal levels. Hence, it may be considered one of its neuroprotective mechanisms. Together, the findings are promising to demonstrate the potential applicability of NOB as a neuroprotectant against chemical-induced neurotoxicity.

Maternal exposure to zinc oxide nanoparticles causes cochlear dysfunction in the offspring

Introduction: Zinc oxide nanoparticles (ZnO NPs) have been engineered and are largely used in material science and industry. This large and increasing use justifies a careful study about the toxicity of this material for human subjects. The concerns regard also the reproductive toxicity and the fetotoxicity. Materials and methods: The effect of the exposure to ZnO NPs on the cochlear function was studied in a group of pregnant CD1 mice and in their offspring. This study is part of a larger toxicological study about the toxicity of ZnO NPs during pregnancy. Four groups were analyzed and compared, exposed and non-exposed dams and their offspring. The cochlear function was quantitatively assessed by means of Distortion Product Otoacoustic Emissions (DPOAEs). Results and discussion: A large statistically significant difference was found between the non-exposed dams offspring and the exposed dams offspring (p = 1.6 · 10-3), whose DPOAE levels were significantly lower than those of non-exposed dams offspring and comparable to those of the adults. The DPOAE levels of the exposed and non-exposed dams were very low and not significantly different. This occurrence is related to the fact that these mice encounter a rapid aging process. Conclusion: Our findings show that maternal exposure to ZnO NPs does not reflect in overt toxicity on fetal development nor impair offspring birth, however it may damage the nervous tissue of the inner ear in the offspring. Other studies should confirm this result and identify the mechanisms through which ZnO NPs may affect ear development.

Nose-to-brain translocation and nervous system injury in response to indium tin oxide nanoparticles of long-term low-dose exposures

Indium tin oxide (ITO) is a semiconductor nanomaterial with broad application in liquid crystal displays, solar cells, and electrochemical immune sensors. It is worth noting that, with the gradual increase in worker exposure opportunities, the exposure risk in occupational production cannot be ignored. At present, the toxicity of ITO mainly focuses on respiratory toxicity. ITO inhaled through the upper respiratory tract can cause pathological changes such as interstitial pneumonia and pulmonary fibrosis. Still, extrapulmonary toxicity after nanoscale ITO nanoparticle (ITO NPs) exposure, such as long-term effects on the central nervous system, should also be of concern. Therefore, we set up exposure dose experiments (0 mg·kg-1, 3.6 mg·kg-1, and 36 mg·kg-1) based on occupational exposure limits to treat C57BL/6 mice via nasal drops for 15 weeks. Moreover, we conducted a preliminary assessment of the neurotoxicity of ITO NPs (20-30 nm) in vivo. The results indicated that ITO NPs can cause diffuse inflammatory infiltrates in brain tissue, increased glial cell responsiveness, abnormal neuronal cell lineage transition, neuronal migration disorders, and neuronal apoptosis related to the oxidative stress induced by ITO NPs exposure. Hence, our findings provide useful information for the fuller risk assessment of ITO NPs after occupational exposure.

Pesticide mediated silent neurotoxicity and its unmasking: An update on recent progress

Being human's one of the most protected organs, brain is yet most vulnerable to xenobiotics exposure. Though pesticide-mediated neurotoxicity is well-explored, the fraternity of neurotoxicologists is less focused on the phenomenon of "silent" or "clinically undetectable" neurotoxicity. Silent neurotoxicity defines continual trivial changes in the nervous system that do not manifest any overt signs of toxicity unless unmasked by any natural or experimental event. Although this perception is not novel, insufficient experimental and epidemiological evidence makes it an outlier among toxicological research. A report in 2016 highlighted the need to investigate silent neurotoxicity and its potential challenges. The limited existing experimental data unveiled the unique responsiveness of neurons following silent neurotoxicity unmasking. Concerned studies have shown that low-dose developmental exposure to pesticides sensitizes the nigrostriatal dopaminergic system towards silent neurotoxicity, making it vulnerable to advanced cumulative neurotoxicity following pesticide challenges later in life. Therefore, conducting such studies may explain the precise etiology of pesticide-induced neurological disorders in humans. With no updates on this topic since 2016, this review is an attempt to acquaint the neurotoxicologist with silent neurotoxicity as a serious threat to human health, and proof-of-concept through a narrative using relevant published data so far with future perspectives.

Transcriptomics and Proteomics Approach for the Identification of Altered Blood microRNAs and Plasma Proteins in Parkinson's Disease

Parkinson's disease (PD) is a neurodegenerative disorder caused by the selective destruction of dopaminergic neurons (DA-nergic). Clinically, PD is diagnosed based on developing signs and symptoms. A neurological and physical examination and sometimes medical and family history also help in the diagnosis of PD. However, most of these features are visible when more than 80% of the dopaminergic neurons have degenerated. An understanding of the selective degeneration process at the cellular and molecular level and the development of new biomarkers are required for effective PD management. Several studies have been carried out using a selected set of miRNAs/ mRNAs and proteins to develop biomarkers of PD; however, an unbiased and combined miRNA-protein profiling study was required to identify the markers of progressive and selected degeneration of dopaminergic neurons in PD patients. In the present study, we have carried out global protein profiling through LC-MS/MS and miRNA profiling by using a "brain-specific" miRNA array panel of 112 miRNAs in PD patients and healthy controls to find the unprejudiced group of proteins and miRNAs that are deregulating in PD. In the whole blood samples of PD patients compared to healthy controls, the expression of 23 miRNAs and 289 proteins was significantly increased, whereas the expression of 4 miRNAs and 132 proteins was considerably downregulated. Network analysis, functional enrichment, annotation, and analysis of miRNA-protein interactions were also performed as part of the bioinformatics investigation of the discovered miRNAs and proteins revealing several pathways that lead to PD development and pathogenesis. Based on the analysis of miRNA and protein profiling, we have identified four miRNAs (hsa-miR-186-5p, miR-29b, miR-139 & has-miR-150-5p) and four proteins (YWHAZ, PSMA4, HYOU1, & SERPINA1), which can be targeted for the development of new biomarkers of PD. In vitro studies have identified the role of miR-186-5p in regulating the levels of the YWHAZ/YWHAB & CALM2 gene, which has shown maximum downregulation in PD patients and is known for its role in neuroprotection from apoptotic cell death & calcium regulation. In conclusion, our research has identified a group of miRNA-proteins that can be developed as PD biomarkers; however, future studies on the release of these miRNAs and proteins in extracellular vesicles circulating in the blood of PD patients can further validate these as specific biomarkers of PD.

Neuroprotective effects of quercetin on the cerebellum of zinc oxide nanoparticles (ZnoNps)-exposed rats

Engineered nanomaterials induce hazardous effects at the cellular and molecular levels. We investigated different mechanisms underlying the neurotoxic potential of zinc oxide nanoparticles (ZnONPs) on cerebellar tissue and clarified the ameliorative role of Quercetin supplementation. Forty adult male albino rats were divided into control group (I), ZnONPs-exposed group (II), and ZnONPs and Quercetin group (III). Oxidative stress biomarkers (MDA & TOS), antioxidant biomarkers (SOD, GSH, GR, and TAC), serum interleukins (IL-1β, IL-6, IL-8), and tumor necrosis factor alpha (TNF-α) were measured. Serum micro-RNA (miRNA): miRNA-21-5p, miRNA-122-5p, miRNA-125b-5p, and miRNA-155-3p expression levels were quantified by real-time quantitative polymerase-chain reaction (RT-QPCR). Cerebellar tissue sections were stained with Hematoxylin & Eosin and Silver stains and examined microscopically. Expression levels of Calbindin D28k, GFAP, and BAX proteins in cerebellar tissue were detected by immunohistochemistry. Quercetin supplementation lowered oxidative stress biomarkers levels and ameliorated the antioxidant parameters that were decreased by ZnONPs. No significant differences in GR activity were detected between the study groups. ZnONPs significantly increased serum IL-1β, IL-6, IL-8, and TNF-α which were improved with Quercetin. Serum miRNA-21-5p, miRNA-122-5p, miRNA-125b-5p, and miRNA-155-p expression levels showed significant increase in ZnONPs group, while no significant difference was observed between Quercetin-treated group and control group. ZnONPs markedly impaired cerebellar tissue structure with decreased levels of calbindin D28k, increased BAX and GFAP expression. Quercetin supplementation ameliorated cerebellar tissue apoptosis, gliosis and improved calbindin levels. In conclusion: Quercetin supplementation ameliorated cerebellar neurotoxicity induced by ZnONPs at cellular and molecular basis by different studied mechanisms.Abbreviations: NPs: Nanoparticles, ROS: reactive oxygen species, ZnONPs: Zinc oxide nanoparticles, AgNPs: silver nanoparticles, BBB: blood-brain barrier, ncRNAs: Non-coding RNAs, miRNA: Micro RNA, DMSO: Dimethyl sulfoxide, LPO: lipid peroxidation, MDA: malondialdehyde, TBA: thiobarbituric acid, TOS: total oxidative status, ELISA: enzyme-linked immunosorbent assay, H2O2: hydrogen peroxide, SOD: superoxide dismutase, GR: glutathione reductase, TAC: total antioxidant capacity, IL-1: interleukin-1, TNF: tumor necrosis factor alpha, cDNA: complementary DNA, RT-QPCR: Real-time quantitative polymerase-chain reaction, ABC: Avidin biotin complex technique, DAB: 3', 3-diaminobenzidine, SPSS: Statistical Package for Social Sciences, ANOVA: One way analysis of variance, Tukey's HSD: Tukey's Honestly Significant Difference, GFAP: glial fiberillar acitic protein, iNOS: Inducible nitric oxide synthase, NO: nitric oxide, HO-1: heme oxygenase-1, Nrf2: nuclear factor erythroid 2-related factor 2, NF-B: nuclear factor-B, SCI: spinal cord injury, CB: Calbindin.

Exploring the Physicochemical, Electroactive, and Biodelivery Properties of Metal Nanoparticles on Peripheral Nerve Regeneration

Despite the advances in the regeneration/rehabilitation field of damaged tissues, the functional recovery of peripheral nerves (PNs), especially in a long gap injury, is considered a great medical challenge. Recent progress in nanomedicine has provided great hope for PN regeneration through the strategy of controlling cell behavior by metal nanoparticles individually or loaded on scaffolds/conduits. Despite the confirmed toxicity of metal nanoparticles due to long-term accumulation in nontarget tissues, they play a role in the damaged PN regeneration based on the topography modification of scaffolds/conduits, enhancing neurotrophic factor secretion, the ion flow improvement, and the regulation of electrical signals. Determining the fate of neural progenitor cells would be a major achievement in PN regeneration, which seems to be achievable by metal nanoparticles through altering cell vital approaches and controlling their functions. Therefore, in this literature, an attempt was made to provide an overview of the effective activities of metal nanoparticles on the PN regeneration, until the vital clues of the PN regeneration and how they are changed by metal nanoparticles are revealed to the researcher.

Nanosafety: An Evolving Concept to Bring the Safest Possible Nanomaterials to Society and Environment

The use of nanomaterials has been increasing in recent times, and they are widely used in industries such as cosmetics, drugs, food, water treatment, and agriculture. The rapid development of new nanomaterials demands a set of approaches to evaluate the potential toxicity and risks related to them. In this regard, nanosafety has been using and adapting already existing methods (toxicological approach), but the unique characteristics of nanomaterials demand new approaches (nanotoxicology) to fully understand the potential toxicity, immunotoxicity, and (epi)genotoxicity. In addition, new technologies, such as organs-on-chips and sophisticated sensors, are under development and/or adaptation. All the information generated is used to develop new in silico approaches trying to predict the potential effects of newly developed materials. The overall evaluation of nanomaterials from their production to their final disposal chain is completed using the life cycle assessment (LCA), which is becoming an important element of nanosafety considering sustainability and environmental impact. In this review, we give an overview of all these elements of nanosafety.

Identification of Altered Blood MicroRNAs and Plasma Proteins in a Rat Model of Parkinson's Disease

Parkinson's disease (PD) is the age-related neurological disorder characterized by the degeneration of dopamine (DA) neurons in the substantia nigra pars compacta (SNpc). PD is based on motor deficits which start to appear when up to 80% of the DA neurons of SNpc have been lost. Effective management of PD requires the development of novel biomarkers. Therefore, the present study aimed to characterize biomarkers of PD using miRNomics, proteomics, and bioinformatics approaches. Rats exposed to rotenone (2.5 mg/kg b.wt) for 2 months were used as an animal model to identify the unbiased set of miRNAs and proteins deregulated in blood samples. OpenArray, a real-time PCR-based array, is used for high-throughput profiling of miRNAs, and liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to carry out the global protein profiling. Systematic bioinformatics analysis of miRNAs and proteins was also performed, including annotation, functional classification and functional enrichment, network analysis, and miRNA-protein interaction analysis. Expression of 19 miRNAs and 96 proteins was significantly upregulated in the blood, while 22 proteins were significantly downregulated in blood samples of rotenone-exposed rats. In silico pathway analysis of deregulated proteins and miRNAs in rotenone-exposed rats has identified multiple pathways leading to PD. In summary, we have identified a set of miRNAs (miR-144, miR-96, and miR-29a) and proteins (PLP1, TUBB4A, and TUBA1C), which can be used as a potential biomarker of PD, while further validation required large human population studies.

Biochemical and Physiological Toxicity of Nanoparticles in Plant

As increasing application of nanoparticles, nanoparticles have been becoming a new emerging environmental pollution that attracts a lot of attention from the scientific community and also regulatory agents. In the past decade, studying the toxicity and environmental impacts of nanoparticles is becoming a hot research field and more and more researches have been published using both plant and animal system. In this chapter, using oxidized metal nanoparticles as an example, we introduce a detailed protocol for performing research on biochemical and physiological toxicity of nanoparticles in plant. We employ a hydroponics system to study phytotoxicity of nanoparticles, which makes it easier to study the impact of nanoparticles. In this chapter, we majorly focus on plant respiration and photosynthesis, root vigor as well as oxidative stress. Oxidative stress is one major physiological response to different environmental pollution, in which we present a detailed method for detecting free radical oxygen species as well as the major molecules and enzymes associating with oxidative stress, including SOD and POD. Although we introduce the methods using cotton as an example, the protocols presented in this chapter can be used almost any plant species to test the biochemical and physiological toxicity of an environmental pollution.

Mutagenicity Evaluation of Nanoparticles by the Ames Assay

The Ames assay is a classic and robust method for identifying and evaluating chemical mutagens that reverse the mutations of Salmonella typhimurium and/or Escherichia coli bacteria strains with amino acid synthesis defects. It is also called the bacterial reverse mutation assay. Ames assay has been widely used for detecting genetic toxicity of many chemicals and gained increased applications in risk assessment of emerging environmental pollutants such as nanomaterials. In this chapter, we presented a detailed step-by-step method using the Ames assay to detect potential mutagenicity of metal oxide nanoparticles. The strategy to use the liver S9 fraction for bioactivation and a preincubation procedure is recommended. This method is easy to use to test genetic toxicity of other environmental contaminants and new chemicals.