Toxic effects of waterborne benzylparaben on the growth, antioxidant capacity and lipid metabolism of Nile tilapia (Oreochromis niloticus)

Mechanism of MWCNTs induced hepatotoxicity in Cyprinus carpio: New perspective from a Lipidomic study

Carbon nanotubes (CNTs), an extensively applied nanomaterial, can cause damage to the liver in fish. However, the underlying lipotoxic modes of CNTs exposure have not been studied. In the present study, juvenile Cyprinus carpio was exposed via water to various doses of multi-walled CNTs (MWCNTs) (0, 0.25, and 2.5 mg L-1) for a consecutive 28-day period. Our results showed elevated hepatosomatic index (HSI) and aspartate aminotransferase (AST) activities in plasma in all exposure groups, indicating that MWCNTs exposure induced liver dysfunction. Significantly increased low-density lipoprotein (LDL) and total cholesterol (CHO) levels along with significantly decreased triglyceride (TG) levels were observed in fish of HSC (2.5 mg L-1 MWCNTs), indicating abnormal lipid metabolism. Subsequently, the livers of fish in the HSC group were harvested for LC-MS/MS-based targeted lipidomic analysis. Changes in the lipid profiles showed 87 and 92 lipids significant up-regulated and down-regulated, respectively. These significantly altered lipids were classed into 20 lipid classes. Among them, Cer, Hex1Cer, CerG2GNAc1, SM, SPH, and phSM belong to sphingolipid. Taken together with our previous findings, these results suggested that the dysregulation of sphingolipid metabolism may be associated with oxidative stress and apoptosis induced by MWCNTs exposure in C. carpio. This study provides new insights into the potential mechanism of MWCNTs in fish, especially from the aspect of lipid metabolism.

Ancestral bisphenol A exposure led to non-alcoholic fatty liver disease and sex-specific alterations in proline and bile metabolism pathways in the liver

Endocrine-disrupting chemicals can induce metabolic alterations, resulting in diseases such as obesity, diabetes, and fatty liver disease, which can be inherited by offspring inhabiting uncontaminated environments. Bisphenol A (BPA), a well-known endocrine disruptor, can induce endocrine disruption, leading to metabolic disorders in subsequent generations without further exposure to BPA via nongenetic transgenerational inheritance. Using medaka as an animal model, we reported that ancestral BPA exposure leads to transgenerational nonalcoholic fatty liver disease (NAFLD) in grandchildren four generations after the initial exposure. It is unclear if transgenerational NAFLD developed because ancestral BPA exposure differs from that developed due to direct and continuous BPA exposure because the transgenerational disease develops in the absence of the stressor. We induced transgenerational NAFLD in medaka with ancestral BPA exposure (10 µg/L) at the F0 generation and examined transcriptional and metabolomic alterations in the liver of the F4 generation fish that continued to develop NAFLD. To understand the etiology of NAFLD in unexposed generations, we performed nontargeted liquid chromatography-mass spectrometry-based metabolomic analysis in combination with bulk RNA sequencing and determined biomarkers, co-expressed gene networks, and sex-specific pathways triggered in the liver. An integrated analysis of metabolomic and transcriptional alterations revealed a positive association with the severity of the NAFLD disease phenotype. Females showed increased NAFLD severity and had metabolic disruption involving proline metabolism, tryptophan metabolism, and bile metabolism pathways. The present results provide the transcriptional and metabolomic underpinning of metabolic disruption caused by ancestral BPA exposure, providing avenues for further research to understand the development and progression of transgenerational NAFLD caused by ancestral bisphenol A exposure.

Bioaccumulation and ecotoxicity of parabens in aquatic organisms: Current status and trends

Parabens are preservatives widely used in personal care products, pharmaceuticals, and foodstuffs. However, they are still unregulated chemical compounds. Given their extensive use and presence in different environmental compartments, parabens can adversely affect animal health. Thus, the current study aimed to summarize and critically analyze the bioaccumulation and ecotoxicity of parabens in aquatic species. Studies have been mostly conducted in laboratory conditions (75%), using mainly fish and crustaceans. Field studies were carried out across 128 sampling sites in six countries. Paraben bioaccumulation was predominantly detected in fish muscle, liver, brain, gills, ovary, and testes. Among the parent parabens, methylparaben (MeP), ethylparaben (EtP), and propylparaben (PrP) have been detected frequently and more abundantly in tissues of marine and freshwater specimens, as well as the metabolite 4-hydroxybenzoic acid (4-HB). Parabens can induce lethal and sublethal effects on aquatic organisms, such as oxidative stress, endocrine disruption, neurotoxicity, behavioral changes, reproductive impairment, and developmental abnormalities. The toxicity of parabens varied according to species, taxonomic group, developmental stage, exposure time, and concentrations tested. This study highlights the potential bioaccumulation and ecotoxicological impacts of parabens and their metabolites on aquatic invertebrates and vertebrates. Additionally, future research recommendations are provided to evaluate the environmental risks posed by paraben contamination more effectively.

Nanopolystyrene and phoxim pollution: A threat to hepatopancreas toxicity in Chinese mitten crab (Eriocheir sinensis)

Significant concerns have been raised by the widespread pollutants phoxim (PHO) and nanopolystyrene (NP) in the natural environment. This study evaluated the toxicity effects on the hepatopancreas of Eriocheir sinensis caused by NP and/or PHO at concentrations found in the environment. Subchronic exposure to NP and/or PHO triggered hepatopancreas histological damage within a 21-day exposure period. The NP, PHO, and co-exposure (NPO) groups exhibited fewer blister-like (B) cells, along with the appearance of vacuolation. Furthermore, these exposures induced impairment in the hepatic tubule mucus barrier and mechanical barrier, as evidenced by altered expression of oxidative stress-related genes, mucin-related genes, and TJ-related genes. Additionally, alterations in immunity-related genes and inflammatory cytokine genes expression were observed. The findings showed that hepatopancreas inflammation was caused by both individual and combined exposure to NP and PHO and that the inflammatory response was exacerbated by the co-exposure. The possible pathways of hepatopancreas toxicity were further investigated by transcriptomic analysis. Hepatopancreas inflammation was brought on by subchronic exposure to PHO and co-exposure; this inflammation was exacerbated by co-exposure and was backed by the activation of NF-κB signaling pathway via targeting-related genes. In summary, this research represents the initial documentation, to the best of our understanding of the detrimental effects of exposured to NP and/or PHO at levels found in the environment disrupt the hepatopancreas mucus and mechanical barrier in crustaceans, triggering inflammatory responses. These findings highlight the significance of NP and/or PHO pollution for hepatopancreas health.

NCI677397 targeting USP24-mediated induction of lipid peroxidation induces ferroptosis in drug-resistant cancer cells

Cancer represents a profound challenge to healthcare systems and individuals worldwide. The development of multiple drug resistance is a major problem in cancer therapy and can result in progression of the disease. In our previous studies, we developed small-molecule inhibitors targeting ubiquitin-specific peptidase 24 (USP24) to combat drug-resistant lung cancer. Recently, we found that the USP24 inhibitor NCI677397 induced ferroptosis, a type of programmed cell death, in drug-resistant cancer cells by increasing lipid reactive oxygen species (ROS) levels. In the present study, we investigated the molecular mechanisms and found that the targeting of USP24 by NCI677397 increased gene expression of most lipogenesis-related genes, such as acyl-CoA synthetase long-chain family member 4 (ACSL4), and activated autophagy. In addition, the activity of several antioxidant enzymes, such as glutathione peroxidase 4 (GPX4) and dihydrofolate reductase (DHFR), was inhibited by NCI677397 treatment via an increase in protein degradation, thereby inducing lipid ROS production and lipid peroxidation. In summary, we demonstrated that NCI677397 induced a marked increase in lipid ROS levels, subsequently causing lipid peroxidation and leading to the ferroptotic death of drug-resistant cancer cells. Our study provides new insights into the clinical use of USP24 inhibitors as ferroptosis inducers (FINs) to block drug resistance during chemotherapy.

Estrogenic disruption effects and formation mechanisms of transformation products during photolysis of preservative parabens

The ubiquitous presence of emerging contaminants (ECs) in the environment and their associated adverse effects has raised concerns about their potential risks. The increased toxicity observed during the environmental transformation of ECs is often linked to the formation of their transformation products (TPs). However, comprehension of their formation mechanisms and contribution to the increased toxicity remains an unresolved challenge. To address this gap, by combining quantum chemical and molecular simulations with photochemical experiments in water, this study investigated the formation of TPs and their molecular interactions related to estrogenic effect using the photochemical degradation of benzylparaben (BZP) preservative as a representative example. A non-targeted analysis was carried out and three previously unknown TPs were identified during the transformation of BZP. Noteworthy, two of these novel TPs, namely oligomers BZP-o-phenol and BZP-m-phenol, exhibited higher estrogenic activities compared to the parent BZP. Their IC50 values of 0.26 and 0.50 μM, respectively, were found to be lower than that of the parent BZP (6.42 μM). The binding free energies (ΔGbind) of BZP-o-phenol and BZP-m-phenol (-29.71 to -23.28 kcal·mol-1) were lower than that of the parent BZP (-20.86 kcal·mol-1), confirming their stronger binding affinities toward the estrogen receptor (ER) α-ligand binding domain. Subsequent analysis unveiled that these hydrophobic residues contributed most favorably to ER binding, with van der Waals interactions playing a significant role. In-depth examination of the formation mechanisms indicated that these toxic TPs primarily originated from the successive cleavage of ester bonds (OCH2C6H5 and COO group), followed by their combination with BZP*. This study provides valuable insight into the mechanisms underlying the formation of toxic TPs and their binding interactions causing the endocrine-disrupting effects. It offers a crucial framework for elucidating the toxicological patterns of ECs with similar structures.

Parabens as environmental contaminants of aquatic systems affecting water quality and microbial dynamics

Among different pollutants of emerging concern, parabens have gained rising interest due to their widespread detection in water sources worldwide. This occurs because parabens are used in personal care products, pharmaceuticals, and food, in which residues are generated and released into aquatic environments. The regulation of the use of parabens varies across different geographic regions, resulting in diverse concentrations observed globally. Concentrations of parabens exceeding 100 μg/L have been found in wastewater treatment plants and surface waters while drinking water (DW) sources typically exhibit concentrations below 6 μg/L. Despite their low levels, the presence of parabens in DW is a potential exposure route for humans, raising concerns for both human health and environmental microbiota. Although a few studies have reported alterations in the functions and characteristics of microbial communities following exposure to emerging contaminants, the impact of the exposure to parabens by microbial communities, particularly biofilm colonizers, remains largely understudied. This review gathers the most recent information on the occurrence of parabens in water sources, as well as their effects on human health and aquatic organisms. The interactions of parabens with microbial communities are reviewed for the first time, filling the knowledge gaps on the effects of paraben exposure on microbial ecosystems and their impact on disinfection tolerance and antimicrobial resistance, with potential implications for public health.

Assessing the greenification potential of cyclodextrin-based molecularly imprinted polymers for pesticides detection

Cyclodextrins, with their unparalleled attributes of eco-friendliness, natural abundance, versatile utility, and facile functionalization, make a paramount contribution to the field of molecular imprinting. Leveraging the unique properties of cyclodextrins in molecularly imprinted polymers synthesis has revolutionized the performance of molecularly imprinted polymers, resulting in enhanced adsorption selectivity, capacity, and rapid extraction of pesticides, while also circumventing conventional limitations. As the concern for food quality and safety continues to grow, the need for standard analytical methods to detect pesticides in food and environmental samples has become paramount. Cyclodextrins, being non-toxic and biodegradable, present an attractive option for greener reagents in imprinting polymers that can also ensure environmental safety post-application. This review provides a comprehensive summary of the significance of cyclodextrins in molecular imprinting for pesticide detection in food and environmental samples. The recent advancements in the synthesis and application of molecularly imprinted polymers using cyclodextrins have been critically analyzed. Furthermore, the current limitations have been meticulously examined, and potential opportunities for greenification with cyclodextrin applications in this field have been discussed. By harnessing the advantages of cyclodextrins in molecular imprinting, it is possible to develop highly selective and efficient methods for detecting pesticides in food and environmental samples while also addressing the challenges of sustainability and environmental impact.

Toxicity of benzyl paraben on aquatic as well as terrestrial life

Parabens are derivatives of alkyl esters of p-hydroxybenzoic acid and come in different classes. These compounds are primarily used as antimicrobial preservative agents in many commercial products, including cosmetics and pharmaceuticals. Accordingly, Benzyl paraben (BeP) is known to be a potential endocrine disruptor. The aim of this study was to determine the toxicity of benzyl paraben (BeP) on aquatic and terrestrial organisms, specifically Scenedesmus sp., Moina macrocopa, and Eisenia fetida. All the organisms were treated with different concentrations of BeP (0.025 mg/L and 1000 mg/L), and LC25, LC50, and LC90 values were used to measure the toxicity levels. Results showed the LC values of BeP for M. macrocopa (3.3 mg/L, 4.7 mg/L, 7.3 mg/L) and E. fetida (173.2 mg/L, 479.8 mg/L, 1062 mg/L), respectively. Toxicity tests on green algae (Scenedesmus sp.) were conducted, the green algae were subjected to various BeP concentration. At 50 mg/L of BeP, cell viability was reduced to 56.2% and the MTT (3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide) assay indicated 35.4% viable cells. The chlorophyll value and the biochemical parameters of the algal cells were corroborative with the cell viability test. Lethal indices (LC50) for M. macrocopa and E. fetida were evaluated for their toxicity on biochemical properties and were found to be catalase (0.111 mg/L, 0.5 mg/L), lipid peroxidation (0.072 mg/L, 0.056 mg/L), and total protein (0.309 mg/L, 0.314 mg/L), respectively. Overall, this study demonstrated the toxic impact of BeP on non-target aquatic as well as terrestrial species.

Butylparaben Exposure Induced Darker Skin Pigmentation in Nile Tilapia (Oreochromis niloticus)

Butylparaben (BuP), as an emerging contaminant with endocrine-disrupting effects, may exert effects on skin pigmentation in fish by interfering with the neuroendocrine system. Therefore, models of BuP exposure in Nile tilapia (Oreochromis niloticus) were established by adding different doses of BuP (0, 5, 50, 500, and 5000 ng/L) for 56 days. The obtained results showed that BuP exposure induced darker skin pigmentation, manifested as increased melanin content of skin, while genes related to melanin synthesis, including α-MSH and Asip2, significantly changed. In addition, BuP exposure reduced dopamine and γ-aminobutyric acid content in the brain, which is related to the synthesis of α-MSH. Furthermore, the release of neurotransmitters from the brain is affected by light. Thus, the relative gene expression levels in the phototransduction pathway were evaluated to explore the molecular mechanism of BuP-induced darker skin pigmentation, and the obtained results showed that Arr3a and Arr3b expression was significantly upregulated, whereas Opsin expression was significantly downregulated in a BuP dose-dependent manner, indicating that BuP inhibited phototransduction from the retina to the brain. Importantly, correlation analysis results showed that all melanin indexes were significantly positively correlated with Arr3b expression and negatively correlated with Opsin expression. This study indicated that BuP induced darker skin pigmentation in Nile tilapia via the neuroendocrine circuit, which reveals the underlying molecular mechanism for the effects of contaminants in aquatic environments on skin pigmentation in fish.

The antipsychotic drug olanzapine altered lipid metabolism in the common carp (Cyprinus carpio L.): Insight from the gut microbiota-SCFAs-liver axis

Olanzapine (OLA) is a common drug used to treat schizophrenia and has recently come under increasing scrutiny as an emerging contaminant. However, its impact on lipid metabolism in fish and its mechanisms of action are not well understood. In this study, common carp were exposed to 0, 10, 100, and 250 μM OLA for 60 days. The results indicated that OLA exposure increased weight gain, total cholesterol (TC), low-density lipoprotein (LDL), and triglycerides (TG) and decreased high-density lipoprotein (HDL). In addition, lipids accumulated in the liver of the common carp. To explore the underlying mechanisms of action, gut microbiota, short-chain fatty acids (SCFAs), liver transcripts, and genes related to lipid metabolism were measured. It was discovered that OLA exposure altered the common carp gut microbiota composition and increased the abundance of SCFA-producing bacteria. Correspondingly, this study showed that OLA exposure increased the levels of SCFAs, which are highly relevant to the development of lipid accumulation. Transcriptome sequencing results indicated that OLA exposure could change lipid metabolism signalling pathways, including steroid biosynthesis, the PPAR signalling pathway, asglycerophospholipid metabolism, glycerolipid metabolism, and fatty acid metabolic pathways of the common carp. Additionally, OLA exposure interrupted lipid metabolism by means of significant upregulation of lipid synthesis-related genes, including pparγ, srebp1, and fas. OLA exposure also resulted in significant lipolysis-related gene downregulation, including cpt, lpl, hsl, and pparα. The results of this study indicated that contamination of aquatic environments with OLA alters lipid metabolism in common carp. In addition, the underlying mechanism might be due in part to the modulation of the gut microbiota-SCFA-PPAR signalling pathway.