Comparative pharyngeal cartilage developmental toxicity of bisphenol A, bisphenol S and bisphenol AF to zebrafish (Danio rerio) larvae: A combination of morphometry and global transcriptome analyses

Molecular mechanisms of environmental pollutant-induced cartilage damage: from developmental disorders to osteoarthritis

The objective of the present study was to review the molecular mechanisms of the adverse effects of environmental pollutants on chondrocytes and extracellular matrix (ECM). Existing data demonstrate that both heavy metals, including cadmium (Cd), lead (Pb), and arsenic (As), as well as organic pollutants, including polychlorinated dioxins and furans (PCDD/Fs) and polychlorinated biphenyls (PCB), bisphenol A, phthalates, polycyclic aromatic hydrocarbons (PAH), pesticides, and certain other organic pollutants that target cartilage ontogeny and functioning. Overall, environmental pollutants reduce chondrocyte viability through the induction apoptosis, senescence, and inflammatory response, resulting in cell death and impaired ECM production. The effects of organic pollutants on chondrocyte development and viability were shown to be mediated by binding to the aryl hydrocarbon receptor (AhR) signaling and modulation of non-coding RNA expression. Adverse effects of pollutant exposures were observed in articular and growth plate chondrocytes. These mechanisms also damage chondrocyte precursors and subsequently hinder cartilage development. In addition, pollutant exposure was shown to impair chondrogenesis by inhibiting the expression of Sox9 and other regulators. Along with altered Runx2 signaling, these effects also contribute to impaired chondrocyte hypertrophy and chondrocyte-to-osteoblast trans-differentiation, resulting in altered endochondral ossification. Several organic pollutants including PCDD/Fs, PCBs and PAHs, were shown to induce transgenerational adverse effects on cartilage development and the resulting skeletal deformities. Despite of epidemiological evidence linking human environmental pollutant exposure to osteoarthritis or other cartilage pathologies, the data on the molecular mechanisms of adverse effects of environmental pollutant exposure on cartilage tissue were obtained from studies in laboratory rodents, fish, or cell cultures and should be carefully extrapolated to humans, although they clearly demonstrate that cartilage should be considered a putative target for environmental pollutant toxicity.

Decrypting the skeletal toxicity of vertebrates caused by environmental pollutants from an evolutionary perspective: From fish to mammals

The rapid development of modern society has led to an increasing severity in the generation of new pollutants and the significant emission of old pollutants, exerting considerable pressure on the ecological environment and posing a serious threat to both biological survival and human health. The skeletal system, as a vital supportive structure and functional unit in organisms, is pivotal in maintaining body shape, safeguarding internal organs, storing minerals, and facilitating blood cell production. Although previous studies have uncovered the toxic effects of pollutants on vertebrate skeletal systems, there is a lack of comprehensive literature reviews in this field. Hence, this paper systematically summarizes the toxic effects and mechanisms of environmental pollutants on the skeletons of vertebrates based on the evolutionary context from fish to mammals. Our findings reveal that current research mainly focuses on fish and mammals, and the identified impact mechanisms mainly involve the regulation of bone signaling pathways, oxidative stress response, endocrine system disorders, and immune system dysfunction. This study aims to provide a comprehensive and systematic understanding of research on skeletal toxicity, while also promoting further research and development in related fields.

Physiological and transcriptomic changes of zebrafish (Danio rerio) in response to Isopropylate Triphenyl Phosphate (IPPP) exposure

Isopropylate Triphenyl Phosphate (IPPP), a novel organophosphorus flame retardant, has become a widespread environmental pollutant. However, the toxic effects and mechanisms of IPPP remain unclear. In this study, we evaluated the neurodevelopmental toxicity effects of IPPP on zebrafish embryonic development, neurobehavior, and physiological and transcriptomic changes. The results showed that IPPP induced adverse developments such as low survival rates and hatching rates, decreased body length and eye distance, and also led to increased heart rates and embryonic malformation rates. The developmental defects mainly included typical pericardial edema, eye deformities, and a reduction in the number of newborn neurons. Mitochondrial energy metabolism disorders and apoptosis of cardiomyocytes may be responsible for heart malformation. Behavioral results showed that IPPP caused abnormal changes in swimming speed, total swimming distance and trajectory, and showed a low-dose effect. In addition, the decreased activity of neurotransmitters such as acetylcholinesterase (AchE) and dopamine (DA), and the changes in genes related to the central nervous system (CNS) and metabolism pathway may be the causes of neurodevelopmental toxicity of IPPP. Meanwhile, IPPP induced oxidative stress and apoptosis, and changed the ATPase activity of zebrafish larvae by altering nuclear factor erythroid2-related factor 2 (Nrf2) and mitochondrial signaling pathways, respectively. Transcriptome sequencing results indicated that Cytochrome P450 and drug metabolism, Energy metabolism-related pathways, Glutathione metabolism, Retinoid acid (RA) and REDOX signaling pathways were significantly enriched, and most of the genes in these pathways were up-regulated after IPPP treatment, which may be new targets for IPPP-induced neurodevelopment. In summary, the results of this study provide an important reference for a comprehensive assessment of the toxic effects and health risks of the new pollutant IPPP.

Removal of bisphenol a micropollutants released from plastic waste using Pt-ZnO photocatalyst

Plastic pollution is becoming increasingly severe and is attracting global attention. One of its consequences is the recent discovery of micropollutant discharge into water, with Bisphenol A (BA-MP) being a typical example. This study utilizes an advanced oxidation process based on Pt-doped ZnO photocatalyst to remove BA-MP. Health concerns related to the release of BA-MP from plastic waste are discussed. Besides, the results of the photodegradation experiment show that the Pt-ZnO photocatalyst can remove 94.1% of BA-MP within 60 min when exposed to solar light. Moreover, after five reuse cycles, Pt-ZnO retains a high BA-MP removal efficiency of 71.2%, and its structure remains largely unchanged compared to the original material. The removal efficiency of BA-MP leaching from plastic waste was measured at 98.8%, confirming the suitability of Pt-ZnO for the treatment of micropollutants. Furthermore, this study also highlights the prospects and challenges of using Pt-ZnO for the treatment of micropollutants discharged from plastic waste.

Sexual dimorphism in neurobehavioural phenotype and gut microbial composition upon long-term exposure to structural analogues of bisphenol-A

Bisphenol S (BPS) and Bisphenol F (BPF), the analogues of the legacy endocrine disrupting chemical, Bisphenol A (BPA) are ubiquitous in the environment and present in various consumer goods, and potentially neurotoxic. Here, we studied sex-specific responses of bisphenols on behavioural phenotypes, including their association with pro-inflammatory biomarkers and altered neurotransmitters levels, and the key gut microbial abundances. Neurobehavioural changes, using standard test battery, biochemical and molecular estimations for inflammatory cytokines, neurotransmitters, and oxido-nitrosative stress markers, gene expression analysis using qRT-PCR, H&E based histological investigations, gut permeability assays and Oxford Nanopore-based 16S-rRNA metagenomics sequencing for the gut microbial abundance estimations were performed. Bisphenol(s) exposure induces anxiety and depression-like behaviours, particularly in the male mice, with heightened pro-inflammatory cytokines levels and systemic endotoxemia, altered monoamine neurotransmitters levels/turnovers and hippocampal neuronal degeneration and inflammatory responses in the brain. They also increased gut permeability and altered microbial diversity, particularly in males. Present study provides evidence for sex-specific discrepancies in neurobehavioural phenotypes and gut microbiota, which necessitate a nuanced understanding of sex-dependent responses to bisphenols. The study contributes to ongoing discussions on the multifaceted implications of bisphenols exposure and underscores the need for tailored regulatory measures to mitigate potential health risks associated with them.

Preliminary investigation into the impact of BPA on osteoblast activity and bone development: In vitro and in vivo models

Bisphenol A (BPA), an ingredient in consumer products, has been suggested that it can interfere with bone development and maintenance, whereas the molecule mechanism remains unclear. The objective of this study is to investigate the effect of BPA on early bone differentiation and metabolism, and its potential molecule mechanism by employing hFOB1.19 cell as an in vitro model, as well as larval zebrafish as an in vivo model. The in vitro experiments indicated that BPA decreased cell viability, inhibited osteogenic activity (such as ALP, RUNX2), increased ROS production, upregulated transcriptional or protein levels of apoptosis-related molecules (such as Caspase 3, Caspase 9), while suppressed transcriptional or protein levels of pyroptosis-specific markers (TNF-α, TNF-β, IL-1β, ASC, Caspase 1, and GSDMD). Moreover, the evidences from in vivo model demonstrated that exposure to BPA distinctly disrupted pharyngeal cartilage, craniofacial bone development, and retarded bone mineralization. The transcriptional level of bone development-related genes (bmp2, dlx2a, runx2, and sp7), apoptosis-related genes (bcl2), and pyroptosis-related genes (cas1, nlrp3) were significantly altered after treating with BPA in zebrafish larvae. In summary, our study, combining in vitro and in vivo models, confirmed that BPA has detrimental effects on osteoblast activity and bone development. These effects may be due to the promotion of apoptosis, the initiation of oxidative stress, and the inhibition of pyroptosis.

A high-affinity fluorescent probe for human uridine-disphosphate glucuronosyltransferase 1A9 function monitoring under environmental pollutant exposure

Uridine-disphosphate glucuronosyltransferase 1A9 (UGT1A9), an important detoxification and inactivation enzyme for toxicants, regulates the exposure level of environmental pollutants in the human body and induces various toxicological consequences. However, an effective tool for high-throughput monitoring of UGT1A9 function under exposure to environmental pollutants is still lacking. In this study, 1,3-dichloro-7-hydroxy-9,9-dimethylacridin-2(9H)-one (DDAO) was found to exhibit excellent specificity and high affinity towards human UGT1A9. Remarkable changes in absorption and fluorescence signals after reacting with UGT1A9 were observed, due to the intramolecular charge transfer (ICT) mechanism. Importantly, DDAO was successfully applied to monitor the biological functions of UGT1A9 in response to environmental pollutant exposure not only in microsome samples, but also in living cells by using a high-throughput screening method. Meanwhile, the identified pollutants that disturb UGT1A9 functions were found to significantly influence the exposure level and retention time of bisphenol S/bisphenol A in living cells. Furthermore, the molecular mechanism underlying the inhibition of UGT1A9 by these pollutant-derived disruptors was elucidated by molecular docking and molecular dynamics simulations. Collectively, a fluorescent probe to characterize the responses of UGT1A9 towards environmental pollutants was developed, which was beneficial for elucidating the health hazards of environmental pollutants from a new perspective.

Improved photocatalytic oxidation of micropollutant in wastewater by solar light: assisted palladium-doped graphitic carbon nitride

The escalating global industrial expansion has led to the extensive release of organic compounds into water bodies, resulting in substantial pollution and posing severe threats to both human health and the ecosystem. Among common micropollutants, bisphenol A (MP-BA) has emerged as a significant endocrine-disrupting chemical with potential adverse effects on human health and the environment. This study aims to develop an efficient photocatalyst, specifically by incorporating palladium-doped graphitic carbon nitride (Pd@GCN), to eliminate MP-BA pollutants present in industrial wastewater. The examination of optical properties and photoluminescence indicates that incorporating Pd into GCN enhances the visible light absorption spectra, which extends beyond 570 nm, and accelerates the separation rate of electron-hole pairs. The photocatalytic degradation efficiency of MP-BA increases from 81.7 to 98.8% as the solution pH rises from 5.0 to 9.0. Moreover, Pd@GCN significantly improves the removal rate of MP-BA in wastewater samples, reaching an impressive 92.8% after 60 min of exposure to solar light. Furthermore, the Pd@GCN photocatalyst exhibits notable reusability over six cycles of MP-BA degradation, indicating its promising potential for the treatment of organic pollutants in wastewater under solar light conditions.

Astaxanthin activates the Nrf2/Keap1/HO-1 pathway to inhibit oxidative stress and ferroptosis, reducing triphenyl phosphate (TPhP)-induced neurodevelopmental toxicity

Triphenyl phosphate (TPhP) serves as a major organophosphorus flame retardant, and its induced neurodevelopmental toxicity has attracted widespread attention, but the mechanism remains unclear. In this study, we involved zebrafish to explore the new mechanism of TPhP inducing oxidative stress and ferroptosis to promote neurodevelopmental toxicity. The results suggested that TPhP affected the embryonic development, reduced the number of new neurons, and led to abnormal neural behavior in zebrafish larvae. TPhP also induced ROS accumulation, activated the antioxidant defense signal Nrf2 and Keap1, and significantly changed the activities of Acetylcholinesterase (AChE), Adenosine triphosphatase (ATPase) and glutathione S-transferase (GST). In addition, TPhP induced ferroptosis in zebrafish, which was reflected in the increase of Fe2+ content, the abnormal expression of GPX4 protein and genes related to iron metabolism (gpx4a, slc7a11, acsl4b, tfa, slc40a1, fth1b, tfr2, tfr1a, tfr1b and ncoa4). Astaxanthin intervention specifically inhibited ROS levels, and reversed SLC7A11 and GPX4 expression levels and Fe2+ metabolism thus alleviating ferroptosis induced by TPhP. Astaxanthin also partially reversed the activity of AChE, GST and the expression of neurodevelopmental-related genes (gap43, gfap, neurog1 and syn2a), so as to partially rescue the embryonic developmental abnormalities and motor behavior disorders induced by TPhP. More interestingly, the expression of mitochondrial apoptosis-related protein BAX, anti-apoptotic protein BCL-2, Caspase3 and Caspase9 was significantly altered in the TPhP exposed group, which could be also reversed by Astaxanthin intervention. In summary, our results suggested that TPhP exposure can induce oxidative stress and ferroptosis, thereby causing neurodevelopment toxicity to zebrafish, while Astaxanthin can partially reverse oxidative stress and reduce the neurodevelopmental toxicity of zebrafish larvae by activating Nrf2/Keap1/HO-1 signaling pathway.

Mechanistic toxicity and growth abnormalities mediated by subacute exposure to environmentally relevant levels of benzophenone-3 in clown anemonefish (Amphiprion ocellaris)

Benzophenone-3 (BP-3) is a UV filter that is ubiquitously present in the environment due to its photostability and degradation resistance and has wide applications in personal care products. BP-3 will eventually be discharged into the ocean. Studies shows BP-3 interferes with endocrine system of aquatic organisms, especially fish. However, the toxicity and mechanisms of subacute exposure of the coral reef fish to BP-3 remain elusive. Here, we exposed the one-month-old clown anemonefish to BP-3 at 1 and 10 μg/L for 14 and 28 days, respectively. After chronic exposure, the effects of BP-3 on the growth of clown anemonefish were investigated in terms of growth-related hormones, immune enzyme activity, digestive enzyme activity, transcriptional profiling of feeding- and obesity-related genes and digital RNA sequencing. The body weight in the BP-3 groups were abnormally increased (1 μg/L group in 14 days treatment and all groups in 28 days treatment), altered insulin content (28 days exposure), immune-related and digestive-related enzymatic activities. At the molecular level, BP-3 interferes with the expression of feeding- and obesity-related genes. Digital RNA sequencing analysis showed that BP-3 interferes with Kyoto encyclopedia of genes and genomes (KEGG) pathways related to growth, social behavior (learning behavior), Mitogen-Activated Protein Kinase (MAPK) signaling pathway, PI3K-Akt signaling pathway, and insulin secretion. Notably, in the insulin secretion, BP-3 induced Ca2+ up-regulation that may damage β cells. Growth abnormalities and social behavior (learning behavior) KEGG pathway disturbances may have potential impacts on populations of clown anemonefish. Our results reveal the toxicological effects of subacute exposure to BP-3, and provides insight into the effects and mechanisms of BP-3 on clown anemonefish growth.

A comprehensive review on environmental pollutants and osteoporosis: Insights into molecular pathways

A significant problem that has an impact on community wellbeing is environmental pollution. Environmental pollution due to air, water, or soil pollutants might pose a severe risk to global health, necessitating intense scientific effort. Osteoporosis is a common chronic condition with substantial clinical implications on mortality, morbidity, and quality of life. It is closely linked to bone fractures. Worldwide, osteoporosis affects around 200 million people, and every year, there are almost 9 million fractures. There is evidence that certain environmental factors may increase the risk of osteoporosis in addition to traditional risk factors. It is crucial to understand the molecular mechanisms at play because there is a connection between osteoporosis and exposure to environmental pollutants such as heavy metals, air pollutants, endocrine disruptors, metal ions and trace elements. Hence, in this scoping review, we explore potential explanations for the link between pollutants and bone deterioration through deep insights into molecular pathways. Understanding and recognizing these pollutants as modifiable risk factors for osteoporosis would possibly help to enhance environmental policy thereby aiding in the improvement of bone health and improving patient quality of life.

Transcriptome Analysis Reveals the Effect of Stocking Density on Energy Metabolism in the Gills of Cherax quadricarinatus under Rice-Crayfish Co-Culture

Stocking density is a crucial factor affecting productivity in aquaculture, and high stocking density is a stressor for aquatic animals. In this study, we aimed to investigate the effects of stocking densities on oxidative stress and energy metabolism in the gills of Cherax quadricarinatus under rice-crayfish farming. The C. quadricarinatus were reared at low density (LD), medium density (MD), and high density (HD) for 90 days. The results showed that the superoxide dismutase (SOD), catalase (CAT), glutathione (GSH), and malondialdehyde (MDA) levels were higher in the HD group than those in the LD group. Transcriptomic analysis revealed 1944 upregulated and 1157 downregulated genes in the gills of the HD group compared to the LD group. Gene ontology (GO) enrichment analysis indicated that these differentially expressed genes (DEGs) were significantly associated with ATP metabolism. KEGG (Kyoto Encyclopedia of Genes and Genomes) analysis also showed that high stocking density resulted in the dysregulation of oxidative phosphorylation. Furthermore, high stocking density upregulated six lipid metabolism-related pathways. Overall, our findings, despite the limited number of samples, suggested that high stocking density led to oxidative stress and dysregulation of energy metabolism in the gills of C. quadricarinatus under rice-crayfish co-culture. Alteration in energy metabolism may be an adaptive response to adverse farming conditions.