Characterization of a ribosomal protein L15 cDNA from Chironomus riparius (Diptera; Chironomidae): Transcriptional regulation by cadmium and silver nanoparticles

Bridging the Gap Between Human Toxicology and Ecotoxicology Under One Health Perspective by a Cross-Species Adverse Outcome Pathway Network for Reproductive Toxicity

Although ecotoxicological and toxicological risk assessments are performed separately from each other, recent efforts have been made in both disciplines to reduce animal testing and develop predictive approaches instead, for example, via conserved molecular markers, and in vitro and in silico approaches. Among them, adverse outcome pathways (AOPs) have been proposed to facilitate the prediction of molecular toxic effects at larger biological scales. Thus, more toxicological data are used to inform on ecotoxicological risks and vice versa. An AOP has been previously developed to predict reproductive toxicity of silver nanoparticles via oxidative stress on the nematode Caenorhabditis elegans (AOPwiki ID 207). Following this previous study, our present study aims to extend the biologically plausible taxonomic domain of applicability (tDOA) of AOP 207. Various types of data, including in vitro human cells, in vivo, and molecular to individual, from previous studies have been collected and structured into a cross-species AOP network that can inform both human toxicology and ecotoxicology risk assessments. The first step was the collection and analysis of literature data to fit the AOP criteria and build a first AOP network. Then, key event relationships were assessed using a Bayesian network modeling approach, which gave more confidence in our overall AOP network. Finally, the biologically plausible tDOA was extended using in silico approaches (Genes-to-Pathways Species Conservation Analysis and Sequence Alignment to Predict Across Species Susceptibility), which led to the extrapolation of our AOP network across over 100 taxonomic groups. Our approach shows that various types of data can be integrated into an AOP framework, and thus facilitates access to knowledge and prediction of toxic mechanisms without the need for further animal testing. Environ Toxicol Chem 2024;00:1-14. © 2024 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Effect of silver nanoparticles on gene transcription of land snail Helix aspersa

Silver nanoparticles (Ag-NPs) are extremely useful in a diverse range of consumer goods. However, their impact on the environment is still under research, especially regarding the mechanisms involved in their effect. Aiming to provide some insight, the present work analyzes the transcriptional activity of six genes (Hsp83, Hsp17.2, Hsp19.8, SOD Cu-Zn, Mn-SOD, and BPI) in the terrestrial snail Helix aspersa in the presence of different concentrations of Ag-NPs. The animals were exposed for seven days to Lactuca sativa soaked for one hour in different concentrations of Ag-NPs (20, 50, 100 mg/L). The results revealed that the highest concentration tested of Ag-NPs (100 mg/L) led to a statistically significant induction of the Hsp83 and BPI expression in the digestive gland compared to the control group. However, a trend to upregulation with no statistical significance was observed for all the genes in the digestive gland and the foot, while in the hemolymph, the trend was to downregulation. Ag-NPs affected the stress response and immunity under the tested conditions, although the impact was weak. It is necessary to explore longer exposure times to confirm that the effect can be maintained and impact on health. Our results highlight the usefulness of the terrestrial snail Helix aspersa as a bioindicator organism for silver nanoparticle pollution biomonitoring and, in particular, the use of molecular biomarkers of pollutant effect as candidates to be included in a multi-biomarker strategy.

In vivo and in silico approaches to assess surface water genotoxicity from Tocantins River, in the cities of Porto Nacional and Palmas, Brazil

The main environmental problem in urban areas, especially in Brazil, is the discharge of untreated sewage. The in vivo Drosophila melanogaster Somatic Mutation and Recombination Test (SMART) was used to assess the genotoxicity of surface waters from three different sites in the Tocantins River, Brazil. The in silico approach was used to search for known and predicted interactions between environmental chemicals found in our samples and Drosophila and human proteins. The genotoxicity tests were performed in standard (ST) and high bioactivation (HB) crosses with samples collected at two periods, the rainy and dry seasons. Mutant spot frequencies found in treatments with unprocessed water from the test sites were compared with the frequencies observed in negative controls. The collection points were represented as sites A, B and C along Tocantins River. Sites A and B are located in Porto Nacional City, whereas site C is located in Palmas City. Considering the rainy season collection, positive responses in the ST cross were observed for sites A and C (89.47% and 85% of recombination, respectively) and in the HB cross for sites A, B and C (88.24%, 84.21% and 82.35% of recombination, respectively). The positive results in the dry season were restricted to sites A and B (88.89% and 85.71% of recombination, respectively) in the HB cross. In accordance with in vivo and in silico results, we hypothesize that ribosomal proteins (RPs) in fruit fly and humans are depleted in cells exposed to heavy metal causing DNA damage and chromosome instability, increasing homologous recombination.

Changes of Gene Expression Patterns from Aquatic Organisms Exposed to Metal Nanoparticles

Metal nanoparticles are used in various branches of industry due to their physicochemical properties. However, with intensive use, most of the waste and by-products from industries and household items, and from weathering of products containing nanoparticles, end up in the waters. These pollutants pose a risk to aquatic organisms, one of which is a change in the expression of various genes. Most of the data that focus on metal nanoparticles and their effects on aquatic organisms are about copper and silver nanoparticles, which is due to their popularity in general industry, but information about other nanoparticulate metals can also be found. This review aims to evaluate gene expression patterns in aquatic organisms by metal nanoparticles, specifying details about the transcription changes of singular genes and, if possible, comparing the changes in the expression of the same genes in different organisms. To achieve this goal, available publications tackling this problem are studied and summarized. Nanometals were found to have a modulatory effect on gene expression in different aquatic organisms. Data show both up-regulation and down-regulation of genes. Nano silver, nano copper, and nano zinc show a regulatory effect on genes involved in inflammation and apoptosis, cell cycle regulation and ROS defense as well as in general stress response and have a negative effect on the expression of genes involved in development. Nano gold, nano titanium, nano zinc, and nano iron tend to elevate the transcripts of genes involved in response to ROS, but also pro-apoptotic genes and down-regulate DNA repair-involved genes and anti-apoptotic-involved genes. Nano selenium showed a rare effect that is protective against harmful effects of other nanoparticles, but also induced up-regulation of stress response genes. This review focuses only on the effects of metal nanoparticles on the expression of various genes of aquatic organisms from different taxonomic groups.

Quantitative proteomic analysis of trachea in fatting pig exposed to ammonia

Ammonia (NH₃) is considered as the main pollutant in livestock houses and air environment, and its adverse effects on animal and human health have attracted widespread attention. However, trachea proteomics respond to NH₃ is lacking, which is crucial to understanding how NH₃ induces respiratory damage. In this study, we performed labeled quantitative proteomic (TMT-MS) analysis in the trachea of fatting pigs exposed to NH₃ for 30 days. The proteomic results were then validated by Immunohistochemistry (IHC) and Parallel Reaction Monitoring (PRM). The results showed that a total of 126 differentially abundant proteins (DAPs) were identified (fold change <0.83 or > 1.2 and P < 0.05), including 70 differentially up-regulated proteins (DUPs) and 56 differentially down-regulated proteins (DDPs). These proteins were mainly located in intracellular regions and involved in immune response, metabolism and protein synthesis. The results of DAPs (EHHADH, RPL28, SLC25A6, TUBB6, CD14, CTSS, RPS11, RPL19, SLC25A5, RPS8, FABP3, RPL21, RPL34, RPL32, PDIA3, FBP1, HSPH1, SAR1A and SEC24C) verified by IHC and PRM were consistent with the proteomic results. The results of this study provided a basis and a novel insight for understanding the mechanism of NH₃-induced tracheal injury. SIGNIFICANCE: Ammonia (NH₃) is considered as the main pollutant in livestock houses and air environment, and its adverse effects on animal and human health have attracted widespread attention. However, trachea proteomics respond to NH₃ is lacking, which is crucial to understanding how NH₃ induces respiratory damage. Therefore, in this study, labeled quantitative proteomics (TMT-MS) was used to detect trachea tissue samples from finishing pigs in NH₃ exposure group and control group, and PRM method was used to further verify the highly abundant proteins in NH₃ exposure samples, so as to identify new diagnostic markers for NH₃ poisoning. The results of this study provided a basis and a novel insight for understanding the molecular pathological mechanism of NH₃-induced tracheal injury.

iTRAQ and PRM-based comparative proteomic profiling in gills of white shrimp Litopenaeus vannamei under copper stress

Crustaceans are particularly sensitive to heavy metal pollution. Copper (Cu) is one of typical heavy metal pollutants in aquatic ecosystems. However, limited attention has been paid on the proteomic responses of shrimp under Cu stress. White shrimp Litopenaeus vannamei held in 5‰ seawater were exposed to 5 mg L^-1 Cu for 3 h, and the regulatory mechanism in the gills was elucidated using iTRAQ-based quantitative proteomics. The results showed that a total of 5034 proteins were identified, 385 differentially expressed proteins (DEPs), including 147 differentially up-regulated proteins (DUPs) and 238 differentially down-regulated proteins (DDPs) were found. Bioinformatics analysis indicated the DEPs responding to Cu stress mainly involved in cytoskeleton, immune response, stress response, protein synthesis, detoxification, ion homeostasis and apoptosis. Furthermore, we still performed PRM analysis on sarcoplasmic calcium binding protein (SCP), serine proteinase inhibitor B3 (SPIB3), C-type lectin 4 (CTL4), cathepsin L (CATHL), JHE-like carboxylesterase 1 (CXE1) and paramyosin (PMY), and biochemical analysis on Cu/Zn-superoxide dismutase (Cu/Zn-SOD) to validate the iTRAQ results, respectively. The present proteome analysis revealed that Cu stress disrupted the ion homeostasis and protein synthesis, and L.vannamei mainly regulates a series of molecular pathways which contained many key proteins involved in the immune process to protect the organism from Cu stress. Our data provides more insight about the underlying mechanisms that related to the stress response of Cu exposure in crustacean.

Season influences the transcriptomic effects of dietary exposure to PVP/PEI coated Ag nanoparticles on mussels Mytilus galloprovincialis

Toxicity of AgNPs has been widely studied in waterborne exposed aquatic organisms. However, toxic effects caused by AgNPs ingested through the diet and depending on the season are still unexplored. The first cell response after exposure to xenobiotics occurs at gene transcription level. Thus, the aim of this study was to assess transcription level effects in the digestive gland of female mussels after dietary exposure to AgNPs both in autumn and in spring. Mussels were fed daily for 21 days with Isochrysis galbana microalgae previously exposed for 24 h to a dose close to environmentally relevant concentrations of 1 μg Ag/L PVP/PEI coated 5 nm AgNPs (in spring) and to a higher dose of 10 μg Ag/L of the same AgNPs both in autumn and in spring. After 1 and 21 days, mussels RNA was hybridized in a custom microarray containing 7806 annotated genes. Mussels were more responsive to the high dose compared to the low dose of AgNPs and a higher number of probes were altered in autumn than in spring. In both seasons, significantly regulated genes were involved in the cytoskeleton and lipid transport and metabolism COG categories, among others, while genes involved in carbohydrate transport and metabolism were specifically altered in autumn. Overall, transcription patterns were differently altered depending on the exposure time and season, indicating that season should be considered in ecotoxicological studies of metal nanoparticles in mussels.

Toxicity and Transcriptome Sequencing (RNA-seq) Analyses of Adult Zebrafish in Response to Exposure Carboxymethyl Cellulose Stabilized Iron Sulfide Nanoparticles

Increasing utilization of stabilized iron sulfides (FeS) nanoparticles implies an elevated release of the materials into the environment. To understand potential impacts and underlying mechanisms of nanoparticle-induced stress, we used the transcriptome sequencing (RNA-seq) technique to characterize the transcriptomes from adult zebrafish exposed to 10 mg/L carboxymethyl cellulose (CMC) stabilized FeS nanoparticles for 96 h, demonstrating striking differences in the gene expression profiles in liver. The exposure caused significant expression alterations in genes related to immune and inflammatory responses, detoxification, oxidative stress and DNA damage/repair. The complement and coagulation cascades Kyoto encyclopedia of genes and genomes (KEGG) pathway was found significantly up-regulated under nanoparticle exposure. The quantitative real-time polymerase chain reaction using twelve genes confirmed the RNA-seq results. We identified several candidate genes commonly regulated in liver, which may serve as gene indicators when exposed to the nanoparticles. Hepatic inflammation was further confirmed by histological observation of pyknotic nuclei, and vacuole formation upon exposure. Tissue accumulation tests showed a 2.2 times higher iron concentration in the fish tissue upon exposure. This study provides preliminary mechanistic insights into potential toxic effects of organic matter stabilized FeS nanoparticles, which will improve our understanding of the genotoxicity caused by stabilized nanoparticles.

Toxicogenomics: A New Paradigm for Nanotoxicity Evaluation

The wider applications of nanoparticles (NPs) has evoked a world-wide concern due to their possible risk of toxicity in humans and other organisms. Aggregation and accumulation of NPs into cell leads to their interaction with biological macromolecules including proteins, nucleic acids and cellular organelles, which eventually induce toxicological effects. Application of toxicogenomics to investigate molecular pathway-based toxicological consequences has opened new vistas in nanotoxicology research. Indeed, genomic approaches appeared as a new paradigm in terms of providing information at molecular levels and have been proven to be as a powerful tool for identification and quantification of global shifts in gene expression. Toxicological responses of NPs have been discussed in this chapter with the aim to provide a clear understanding of the molecular mechanism of NPs induced toxicity both in in vivo and in vitro test models.

The ribosome biogenesis pathway as an early target of benzyl butyl phthalate (BBP) toxicity in Chironomus riparius larvae

Butyl benzyl phthalate (BBP) is a ubiquitous contaminant whose presence in the environment is expected for decades, since it has been extensively used worldwide as a plasticizer in the polyvinyl chloride (PVC) industry and the manufacturing of many other products. In the present study, the interaction of BBP with the ribosome biogenesis pathway and the general transcriptional profile of Chironomus riparius aquatic larvae were investigated by means of changes in the rDNA activity (through the study of the internal transcribed spacer 2, ITS2) and variations in the expression profile of ribosomal protein genes (rpL4, rpL11, and rpL13) after acute 24-h and 48-h exposures to a wide range of BBP doses. Furthermore, cytogenetic assays were conducted to evaluate the transcriptional activity of polytene chromosomes from salivary gland cells, with special attention to the nucleolus and the Balbiani rings (BRs) of chromosome IV. BBP caused a dose and time-dependent toxicity in most of the selected biomarkers, with a general depletion in the gene expression levels and the activity of BR2 after 48-h treatments. At the same time, decondensation and activation of some centromeres took place, while the activity of nucleolus remained unaltered. Withdrawal of the xenobiotic allowed the larvae to reach control levels in the case of rpL4 and rpL13 genes, which were previously slightly downregulated in 24-h tests. These data provide the first evidence on the interaction of BBP with the ribosome synthesis pathways, which results in a significant impairment of the functional activity of ribosomal protein genes. Thus, the depletion of ribosomes would be a long-term effect of BBP-induced cellular damage. These findings may have important implications for understanding the adverse biological effects of BBP in C. riparius, since they provide new sensitive biomarkers of BBP exposure and highlight the suitability of this organism for ecotoxicological risk assessment, especially in aquatic ecosystems.

Ecdysone-Related Biomarkers of Toxicity in the Model Organism Chironomus riparius: Stage and Sex-Dependent Variations in Gene Expression Profiles

Despite being considered a model organism in toxicity studies, particularly in assessing the environmental impact of endocrine disrupting compounds (EDCs) and other chemicals, the molecular basis of development is largely unknown in Chironomus riparius. We have characterized the expression patterns of important genes involved in the ecdysone pathway from embryos to pupa, but specially during the different phases of C. riparius fourth larval instar, according to the development of genital and thoracic imaginal discs. Real-Time PCR was used to analyze: EcR and usp, two genes encoding the two dimerizing partners of the functional ecdysone receptor; E74, an early response gene induced by ecdysteroids; vg (vitellogenin), an effector gene; hsp70 and hsc70, two heat-shock genes involved in the correct folding of the ecdysone receptor; and rpL13, as a part of the ribosomal machinery. Our results show for the first time stage and sex-dependent variations in ecdysone-responsive genes, specially during the late larval stage of C. riparius. The induction in the expression of EcR and usp during the VII-VIII phase of the fourth instar is concomitant with a coordinated response in the activity of the other genes analyzed, suggesting the moment where larvae prepare for pupation. This work is particularly relevant given that most of the analyzed genes have been proposed previously in this species as sensitive biomarkers for the toxicological evaluation of aquatic ecosystems. Identifying the natural regulation of these molecular endpoints throughout the Chironomus development will contribute to a more in-depth and accurate evaluation of the disrupting effects of EDCs in ecotoxicological studies.

The plasticizer benzyl butyl phthalate (BBP) alters the ecdysone hormone pathway, the cellular response to stress, the energy metabolism, and several detoxication mechanisms in Chironomus riparius larvae

Butyl benzyl phthalate (BBP) has been extensively used worldwide as a plasticizer in the polyvinyl chloride (PVC) industry and the manufacturing of many other products, and its presence in the aquatic environment is expected for decades. In the present study, the toxicity of BBP was investigated in Chironomus riparius aquatic larvae. The effects of acute 24-h and 48-h exposures to a wide range of BBP doses were evaluated at the molecular level by analysing changes in genes related to the stress response, the endocrine system, the energy metabolism, and detoxication pathways, as well as in the enzyme activity of glutathione S-transferase. BBP caused a dose and time-dependent toxicity in most of the selected biomarkers. 24-h exposures to high doses affected larval survival and lead to a significant response of several heat-shock genes (hsp70, hsp40, and hsp27), and to a clear endocrine disrupting effect by upregulating the ecdysone receptor gene (EcR). Longer treatments with low doses triggered a general repression of transcription and GST activity. Furthermore, delayed toxicity studies were specially relevant, since they allowed us to detect unpredictable toxic effects, not immediately manifested after contact with the phthalate. This study provides novel and interesting results on the toxic effects of BBP in C. riparius and highlights the suitability of this organism for ecotoxicological risk assessment, especially in aquatic ecosystems.

Label-free silver nanoparticles for the naked eye detection of entecavir

A simple, rapid, field-portable colorimetric method for the detection of entecavir was proposed based on the color change caused by the aggregation of silver nanoparticles. Neutralization of the electrostatic repulsion from each silver nanoparticle resulted in the aggregation of AgNPs and a consequent color change of AgNPs from yellow to wine-red, which provided a platform for rapid and field-portable colorimetric detection of entecavir. The concentration of entecavir could be determined with naked eye or UV-vis spectrometer. The proposed method can be used to detect entecavir in human urine with a detection limit of 1.51μg mL(-1), within 25min by naked eye observation without the aid of any advanced instrument or complex pretreatment. Results from UV-vis spectra showed that the absorption ratio was linear with the concentration of entecavir in the range of 5.04-25.2μg mL(-1) and 1.01-5.04μg mL(-1) with linear coefficients of 0.9907 and 0.9955, respectively. The selectivity of AgNPs detection system for entecavir is excellent comparing with other ions and analytes. Due to its rapid, visible color changes, and excellent selectivity, the AgNPs synthesized in this study are suitable to be applied to on-site screening of entecavir in human urine.

Transcriptome sequencing (RNA-seq) analysis of the effects of metal nanoparticle exposure on the transcriptome of Chlamydomonas reinhardtii

The widespread use of nanoparticles (NPs) raises concern over their potential toxicological effects in humans and ecosystems. Here we used transcriptome sequencing (RNA-seq) to evaluate the effects of exposure to four different metal-based NPs, nano-Ag (nAg), nano-TiO2 (nTiO2), nano-ZnO (nZnO), and CdTe/CdS quantum dots (QDs), in the eukaryotic green alga Chlamydomonas reinhardtii. The transcriptome was characterized before and after exposure to each NP type. Specific toxicological effects were inferred from the functions of genes whose transcripts either increased or decreased. Data analysis resulted in important differences and also similarities among the NPs. Elevated levels of transcripts of several marker genes for stress were observed, suggesting that only nZnO caused nonspecific global stress to the cells under environmentally relevant conditions. Genes with photosynthesis-related functions were decreased drastically during exposure to nTiO2 and slightly during exposures to the other NP types. This pattern suggests either toxicological effects in the chloroplast or effects that mimic a transition from low to high light. nAg exposure dramatically elevated the levels of transcripts encoding known or predicted components of the cell wall and the flagella, suggesting that it damages structures exposed to the external milieu. Exposures to nTiO2, nZnO, and QDs elevated the levels of transcripts encoding subunits of the proteasome, suggesting proteasome inhibition, a phenomenon believed to underlie the development and progression of several major diseases, including Alzheimer's disease, and used in chemotherapy against multiple myeloma.

Molecular mechanisms of toxicity of silver nanoparticles in zebrafish embryos

Silver nanoparticles cause toxicity in exposed organisms and are an environmental health concern. The mechanisms of silver nanoparticle toxicity, however, remain unclear. We examined the effects of exposure to silver in nano-, bulk-, and ionic forms on zebrafish embryos (Danio rerio) using a Next Generation Sequencing approach in an Illumina platform (High-Throughput SuperSAGE). Significant alterations in gene expression were found for all treatments and many of the gene pathways affected, most notably those associated with oxidative phosphorylation and protein synthesis, overlapped strongly between the three treatments indicating similar mechanisms of toxicity for the three forms of silver studied. Changes in oxidative phosphorylation indicated a down-regulation of this pathway at 24 h of exposure, but with a recovery at 48 h. This finding was consistent with a dose-dependent decrease in oxygen consumption at 24 h, but not at 48 h, following exposure to silver ions. Overall, our data provide support for the hypothesis that the toxicity caused by silver nanoparticles is principally associated with bioavailable silver ions in exposed zebrafish embryos. These findings are important in the evaluation of the risk that silver particles may pose to exposed vertebrate organisms.

Gene expression of ribosomal protein mRNA in Chironomus riparius: effects of endocrine disruptor chemicals and antibiotics

Ribosomal protein genes are essential for cellular development. To examine the effects of ribosomal protein genes under various cellular stress conditions in chironomids, ribosomal protein S3 (RpS3) and S6 (RpS6) cDNA from Chironomus riparius were characterized and their expression was analyzed during development. A comparative and phylogenetic study among different orders of insects was carried out by analysis of sequence databases. C. riparius RpS3 was highly conserved at the protein level and shared over 85% amino acid identity with homologous sequences from other insects. RpS6 also showed approximately 80% amino acid identity. The RpS3 and S6 transcripts were present during different developmental stages but were most abundant during the embryonic stage. Furthermore, expression of the previously reported ribosomal proteins RpL11, L13, and L15, as well as RpS3 and S6 was analyzed following exposure to various concentrations of three endocrine disruptor chemicals (EDCs), di(2-ethylhexyl) phthalate, bisphenol A, and 4-nonylphenol (4NP), and the veterinary antibiotics (VAs) fenbendazole, sulfathiazole, and lincomycin. Only RpS3 gene expression was up-regulated significantly in response to EDCs and fenbendazole. However, the C. riparius ribosomal proteins showed a limited response to cellular stress, following exposure to EDCs and VAs.

Characterization and transcriptional regulation of thioredoxin reductase 1 on exposure to oxidative stress inducing environmental pollutants in Chironomus riparius

We characterized thioredoxin reductase 1 (TrxR1) from Chironomus riparius (CrTrxR1) and studied its expression under oxidative stress. The full-length cDNA is 1820bp long and contains an open reading frame (ORF) of 1488bp. The deduced CrTrxR1 protein has 495 amino acids and a calculated molecular mass of 54.41kDa and an isoelectric point of 6.15. There was a 71bp 5' and a 261bp 3' untranslated region with a polyadenylation signal site (AATAAA). Homologous alignments showed the presence of conserved catalytic domain Cys-Val-Asn-Val-Gly-Cys (CVNVGC), the C-terminal amino acids 'CCS' and conserved amino acids required in catalysis. The expression of CrTrxR1 is measured using quantitative real-time PCR after exposure to 50 and 100mg/L of paraquat (PQ) and 2, 10 and 20mg/L of cadmium chloride (Cd). CrTrxR1 mRNA was upregulated after PQ exposure at all conditions tested. The highest level of CrTrxR1 expression was observed after exposure to 10mg/L of Cd for 24h followed by 20mg/L for 48h. Significant downregulation of CrTrxR1 was observed after exposure to 10 and 20mg/L of Cd for 72h. This study shows that the CrTrxR1 could be potentially used as a biomarker of oxidative stress inducing environmental contaminants.