Physiological, Transcriptome, and Metabolome Analyses Reveal the Tolerance to Cu Toxicity in Red Macroalgae Gracilariopsis lemaneiformis.

Heavy metal copper (Cu) will inevitably impact the marine macroalgae Gracilariopsis lemaneiformis (G. lemaneiformis), which is a culture of economic importance along China's coastline. In this study, the detoxification mechanism of Cu stress on G. lemaneiformis was revealed by assessing physiological indicators in conjunction with transcriptome and metabolome analyses at 1 d after Cu stress. Our findings revealed that 25 µM Cu stimulated ROS synthesis and led to the enzymatic oxidation of arachidonic acid residues. This process subsequently impeded G. lemaneiformis growth by suppressing photosynthesis, nitrogen metabolism, protein synthesis, etc. The entry of Cu ions into the algae was facilitated by ZIPs and IRT transporters, presenting as Cu2+. Furthermore, there was an up-regulation of Cu efflux transporters HMA5 and ABC family transporters to achieve compartmentation to mitigate the toxicity. The results revealed that G. lemaneiformis elevated the antioxidant enzyme superoxide dismutase and ascorbate-glutathione cycle to maintain ROS homeostasis. Additionally, metabolites such as flavonoids, 3-O-methylgallic acid, 3-hydroxy-4-keto-gama-carotene, and eicosapentaenoic acid were up-regulated compared with the control, indicating that they might play roles in response to Cu stress. In summary, this study offers a comprehensive insight into the detoxification mechanisms driving the responses of G. lemaneiformis to Cu exposure.

Biological effects of a copper-based fungicide on the fruit fly, Drosophila melanogaster.

The increased consumption of pesticides can have a negative environmental impact by increasing the essential metals to toxic levels. Bordasul® is a commonly used fungicide in Brazil and it is composed of 20% Cu, 10% sulfur, and 3.0% calcium. The study of fungicides in vivo in non-target model organisms can predict their environmental impact more broadly. The Drosophila melanogaster is a unique model due to its ease of handling and maintenance. Here, the potential toxicity of Bordasul® was investigated by assessing the development, survival, and behavior of exposed flies. Exposure to Bordasul® impaired the development (p < 0.01) and caused a significant reduction in memory retention (p < 0.05) and locomotor ability (p < 0.001). Fungicides are needed to assure the world's food demand; however, Bordasul® was highly toxic to D. melanogaster. Therefore, Bordasul® may be potentially toxic to non-target invertebrates and new environmentally-safe biofertilizers have to be developed to preserve the biota.

Retinoic acid mitigates the NSC319726-induced spermatogenesis dysfunction through cuproptosis-independent mechanisms.

Copper ionophore NSC319726 has attracted researchers' attention in treating diseases, particularly cancers. However, its potential effects on male reproduction during medication are unclear. This study aimed to determine whether NSC319726 exposure affected the male reproductive system. The reproductive toxicity of NSC319726 was evaluated in male mice following a continuous exposure period of 5 weeks. The result showed that NSC319726 exposure caused testis index reduction, spermatogenesis dysfunction, and architectural damage in the testis and epididymis. The exposure interfered with spermatogonia proliferation, meiosis initiation, sperm count, and sperm morphology. The exposure also disturbed androgen synthesis and blood testis barrier integrity. NSC319726 treatment could elevate the copper ions in the testis to induce cuproptosis in the testis. Copper chelator rescued the elevated copper ions in the testis and partly restored the spermatogenesis dysfunction caused by NSC319726. NSC319726 treatment also decreased the level of retinol dehydrogenase 10 (RDH10), thereby inhibiting the conversion of retinol to retinoic acid, causing the inability to initiate meiosis. Retinoic acid treatment could rescue the meiotic initiation and spermatogenesis while not affecting the intracellular copper ion levels. The study provided an insight into the bio-safety of NSC319726. Retinoic acid could be a potential therapy for spermatogenesis impairment in patients undergoing treatment with NSC319726.

Combined effects of micron-sized polyvinyl chloride particles and copper on seed germination of perilla.

Microplastics (MPs) and copper (Cu) pollution coexist widely in cultivation environment. In this paper, polyvinyl chloride (PVC) were used to simulate the MPs exposure environment, and the combined effects of MPs + Cu on the germination of perilla seeds were analyzed. The results showed that low concentrations of Cu promoted seed germination, while medium to high concentrations exhibited inhibition and deteriorated the morphology of germinated seeds. The germination potential, germination index and vitality index of 8 mg • L-1 Cu treatment group with were 23.08%, 76.32% and 65.65%, respectively, of the control group. The addition of low concentration PVC increased the above indicators by 1.27, 1.15, and 1.35 times, respectively, while high concentration addition led to a decrease of 65.38%, 82.5%, and 66.44%, respectively. The addition of low concentration PVC reduced the amount of PVC attached to radicle. There was no significant change in germination rate. PVC treatment alone had no significant effect on germination. MPs + Cu inhibited seed germination, which was mainly reflected in the deterioration of seed morphology. Cu significantly enhanced antioxidant enzyme activity, increased reactive oxygen species (ROS) and MDA content. The addition of low concentration PVC enhanced SOD activity, reduced MDA and H2O2 content. The SOD activity of the Cu2+8 + PVC10 group was 4.05 and 1.35 times higher than that of the control group and Cu treatment group at their peak, respectively. At this time, the CAT activity of the Cu2+8 + PVC5000 group increased by 2.66 and 1.42 times, and the H2O2 content was 2.02 times higher than the control. Most of the above indicators reached their peak at 24 h. The activity of α-amylase was inhibited by different treatments, but ß-amylase activity, starch and soluble sugar content did not change regularly. The research results can provide new ideas for evaluating the impact of MPs + Cu combined pollution on perilla and its potential ecological risk.

Cope with copper: From molecular mechanisms of cuproptosis to copper-related kidney diseases.

Cuproptosis has recently been identified as a novel regulatory mechanism of cell death. It is characterized by the accumulation of copper in mitochondria and its binding to acylated proteins. These characteristics lead to the downregulation of iron-sulfur cluster proteins and protein toxicity stress, ultimately resulting in cell death. Cuproptosis is distinct from other types of cell death, including necrosis, apoptosis, ferroptosis, and pyroptosis. Cu induces oxidative stress damage, protein acylation, and the oligomerization of acylated TCA cycle proteins. These processes lead to the downregulation of iron-sulfur cluster proteins and protein toxicity stress, disrupting cellular Cu homeostasis, and causing cell death. Cuproptosis plays a significant role in the development and progression of various kidney diseases such as acute kidney injury, chronic kidney disease, diabetic nephropathy, kidney transplantation, and kidney stones. On the one hand, inducers of cuproptosis, such as disulfiram (DSF), chloroquinolone, and elesclomol facilitate cuproptosis by promoting cell oxidative stress. In contrast, inhibitors of Cu chelators, such as tetraethylenepentamine and tetrathiomolybdate, relieve these diseases by inhibiting apoptosis. To summarize, cuproptosis plays a significant role in the pathogenesis of kidney disease. This review comprehensively discusses the molecular mechanisms underlying cuproptosis and its significance in kidney diseases.

Cu-II-directed self-assembly of fullerenols to ameliorate copper stress in maize seedlings.

Widespread use of copper-based agrochemical may cause copper excessive accumulation in agricultural soil to seriously threaten crop production. Recently, fullerenols are playing important roles in helping crops build resistance to abiotic stresses by giving ingenious and successful resolutions. However, there is a lack of knowledge on their beneficial effects in crops under stresses induced by heavy metals. Herein, the visual observation of Cu2+-mediated assembly of fullerenols via electrostatic and coordination actions was carried out in vitro, showing that water-soluble nanocomplexes and water-insoluble cross-linking nanohybrids were selectively fabricated by precisely adjusting feeding ratios of fullerenols and CuSO4. Furthermore, maize simultaneous exposure of fullerenols and CuSO4 solutions was tested to investigate the comparative effects of seed germination and seedling growth relative to exposure of CuSO4 alone. Under moderate Cu2+ stresses (40 and 80 µM), fullerenols significantly mitigated the detrimental effects of seedlings, including phenotype, root and shoot elongation, biomass accumulation, antioxidant capacity, and Cu2+ uptake and copper transporter-related gene expressions in roots. Under 160 µM of Cu2+ as a stressor, fullerenols also accelerated germination of Cu2+-stressed seeds eventually up to the level of the control. Summarily, fullerenols can enhance tolerance of Cu2+-stressed maize mainly due to direct detoxification through fullerenol-Cu2+ interactions restraining the Cu2+ intake into roots and reducing free Cu2+ content in vivo, as well as fullerenol-maize interactions to enhance resistance by maintaining balance of reactive oxygen species and optimizing the excretion and transport of Cu2+. This will unveil valuable insights into the beneficial roles of fullerenols and its mechanism mode in alleviating heavy metal stress on crop plants.

Embryo growth alteration and oxidative stress responses in germinating Cucurbita pepo seeds exposed to cadmium and copper toxicity.

This study investigated the influence of cadmium (Cd) and copper (Cu) heavy metals on germination, metabolism, and growth of zucchini seedlings (Cucurbita pepo L.). Zucchini seeds were subjected to two concentrations (100 and 200 µM) of CdCl2 and CuCl2. Germination parameters, biochemical and phytochemical attributes of embryonic axes were assessed. Results revealed that germination rate remained unaffected by heavy metals (Cd, Cu). However, seed vigor index (SVI) notably decreased under Cd and Cu exposure. Embryonic axis length and dry weight exhibited significant reductions, with variations depending on the type of metal used. Malondialdehyde and H2O2 content, as well as catalase activity, did not show a significant increase at the tested Cd and Cu concentrations. Superoxide dismutase activity decreased in embryonic axis tissues. Glutathione S-transferase activity significantly rose with 200 µM CdCl2, while glutathione content declined with increasing Cd and Cu concentrations. Total phenol content and antioxidant activity increased at 200 µM CuCl2. In conclusion, Cd and Cu heavy metals impede zucchini seed germination efficiency and trigger metabolic shifts in embryonic tissue cells. Response to metal stress is metal-specific and concentration-dependent. These findings contribute to understanding the intricate interactions between heavy metals and plant physiology, aiding strategies for mitigating their detrimental effects on plants.

Toxic mechanism in Daphnia magna due to phthalic acid esters and CuO nanoparticles co-exposure: The insight of physiological, microbiomic and metabolomic profiles.

Various phthalic acid esters (PAEs) such as dibutyl phthalate (DBP) and butyl benzyl phthalate (BBP) co-exist with nanopollutants in aquatic environment. In this study, Daphnia magna was exposed to nano-CuO and DBP or BBP at environmental relevant concentrations for 21-days to investigate these combined toxic effects. Acute EC50 values (48 h) of nano-CuO, DBP, and BBP were 12.572 mg/L, 8.978 mg/L, and 4.785 mg/L, respectively. Results showed that co-exposure with nano-CuO (500 µg/L) for 21 days significantly enhanced the toxicity of DBP (100 µg/L) and BBP (100 µg/L) to Daphnia magna by 18.37% and 18.11%, respectively. The activities of superoxide dismutase, catalase, and glutathione S-transferase were enhanced by 10.95% and 14.07%, 25.63% and 25.91%, and 39.93% and 35.01% in nano-CuO+DBP and nano-CuO+BBP treatments as compared to the individual exposure groups, verifying that antioxidative defense responses were activated. Furthermore, the co-exposure of nano-CuO and PAEs decreased the population richness and diversity microbiota, and changed the microbial community composition in Daphnia magna. Metabolomic analysis elucidated that nano-CuO + PAEs exposure induced stronger disturbance on metabolic network and molecular function, including amino acid, nucleotides, and lipid metabolism-related metabolic pathways, as comparison to PAEs single exposure treatments. In summary, the integration of physiological, microflora, and untargeted metabolomics analysis offers a fresh perspective into the potential ecological risk associated with nanopollutants and phthalate pollution in aquatic ecosystems.

Bioavailability and Toxicity of nano Copper Oxide to Pakchoi (Brassica Campestris L.) as Compared with bulk Copper Oxide and Ionic Copper.

The increasing use of copper oxide nano particles (nCuO) as nano-fertilizers and pesticides have raised concerns over their impact on soil environment and agricultural products. In this study, two nCuO with different shapes, namely spherical nCuO (CuO NPs) and tubular nCuO (CuO NTs), were selected to investigate their bioavailability and toxicity to pakchoi in two soils with different properties. At the meantime, CuO bulk particles (CuO BPs) and Cu(NO3)2 were used for comparison. Results showed that all the Cu treatments increased the DTPA extractable (DTPA-Cu) concentrations in GD soil (acidic) more than in HN soil (alkaline). The DTPA-Cu concentrations increased in the order of Cu(NO3)2 ≈ CuO NPs > CuO BPs ≈ CuO NTs in GD soil and Cu(NO3)2 > CuO NPs > CuO BPs ≈ CuO NTs in HN soil. While for the contents of Cu in the aerial parts of pakchoi, the order is CuO NPs > Cu(NO3)2 > CuO NTs ≈ CuO BPs in GD soil and CuO NPs ≈ Cu(NO3)2 > CuO BPs ≈ CuO NTs in HN soil. Only CuO NPs reduced pakchoi biomass in GD soil. There are no significant difference among CuO NPs, CuO BPs, and Cu(NO3)2 in reducing the chlorophyll contents in pakchoi in HN soil, whereas in GD soil, CuO NPs and CuO BPs led to significantly lower chlorophyll contents in pakchoi compared to Cu(NO3)2. Additionally, CuO NPs and Cu(NO3)2 increased Mn and Mo in pakchoi leaf in HN soil, while increased Zn in pakchoi leaf in GD soil. These results indicated that CuO NPs showed higher or comparable toxicity and bioavailability to pakchoi compared with Cu(NO3)2 depending on soil properties, and nCuO are more easily to be transferred from roots to the aerial parts than CuO BPs and Cu(NO3)2.

Effects of Cu2O nanoparticles on the kinetic characteristics of rapid chlorophyll fluorescence induction and related genes in wheat seedlings.

Metal nanoparticles could be accumulated in soils, which threatens the ecological stability of crops. Investigating the effects of cuprous oxide nanoparticles (Cu2O-NPs) on photosystem Ⅱ (PSⅡ) of wheat seedling leaves holds considerable importance in comprehending the implications of Cu2O-NPs on crop photosynthesis. Following the hydroponic method, we investigated the effects of 0, 10, 50, 100, and 200 mg·L-1 Cu2O-NPs on chlorophyll fluorescence induction kinetics and photosynthetic-related genes in wheat seedlings of "Zhoumai 18". The results showed that, with the increases of Cu2O-NPs concentrations, chlorophyll contents in wheat leaves decreased, and the standardization of the OJIP curve showed a clearly K-phase (ΔK＞0). Cu2O-NPs stress increased the parameters of active PSⅡ reaction centers, including the absorption flux per active RC (ABS/RC), the trapping flux per active RC (TRo/RC), the electron transport flux per active RC (ETo/RC), and the dissipation flux per active RC (DIo/RC). Cu2O-NPs stress decreased the parameters of PSⅡ energy distribution ratio including the maximum quantum yield of PSⅡ (φPo), the quantum yield of electron transport from QA (φEo), and the probability that a trapped exciton moved an electron further than QA (Ψo), while increased the quantum ratio for heat dissipation (φDo). Moreover, there was a decrease in photosynthetic quantum yield Y(Ⅱ), photochemical quenching coefficient (qP), net photosynthetic rate (Pn), stomatal conductance (gs), intercellular CO2 concentration (Ci), and transpiration rate (Tr) of leaves with the increases of Cu2O-NPs concentration. Under Cu2O-NPs stress, the expression levels of genes which included PSⅡ genes (PsbD, PsbP, Lhcb1), Rubisco large subunit genes (RbcL), cytochrome b6/f complex genes (PetD, Rieske), and ATP synthase genes (AtpA, AtpB, AtpE, AtpI) were downregulated. These results indicated that Cu2O-NPs stress altered the activity and structure of PSⅡ in wheat seedlings, affected the activity of PSⅡ reaction centers, performance parameters of PSⅡ donor and acceptor sides. PSⅡ related genes were downregulated and exhibited significant concentration effects.

Comprehensive effects of salinity, dissolved organic carbon and copper on mortality, osmotic regulation and bioaccumulation of copper in Oryzias melastigma.

Cu, as an essential and toxic element, has gained widespread attention. Both salinity and dissolved organic carbon (DOC) are known to influence Cu toxicity in marine organisms. However, the intricate interplay between these factors and their specific influence on Cu toxicity remains ambiguous. So, this study conducted toxicity tests of Cu on Oryzias melastigma. The experiments involved three salinity levels (10, 20, and 30 ppt) and three DOC levels (0, 1, and 5 mg/L) to comprehensively investigate the underlying mechanisms of toxicity. The complex toxic effects were analyzed by mortality, NKA activity, net Na+ flux and Cu bioaccumulation in O. melastigma. The results indicate that Cu toxicity is notably influenced by both DOC and salinity. Interestingly, the discernible variation in Cu toxicity across different DOC levels diminishes as salinity levels increase. The presence of DOC enhances the impact of salinity on Cu toxicity, especially at higher Cu concentrations. Additionally, Visual MINTEQ was utilized to elucidate the chemical composition of Cu, revealing that DOC had a significant impact on Cu forms. Furthermore, we observed that fluctuations in salinity lead to the inhibition of Na+/K+-ATPase (NKA) activity, subsequently hindering the inflow of Na+. The effects of salinity and DOC on the bioaccumulation of copper were not significant. The influence of salinity on Cu toxicity is mainly through its effect on the osmotic regulation and biophysiology of O. melastigma. Additionally, DOC plays a crucial role in the different forms of Cu. Moreover, DOC-Cu complexes can be utilized by organisms. This study contributes to understanding the mechanism of copper's biological toxicity in intricate marine environments and serves as a valuable reference for developing marine water quality criteria for Cu.

Comprehensive assessment of copper's effect on marine organisms under ocean acidification and warming in the 21st century.

Copper (Cu) has sparked widespread global concern as one of the most hazardous metals to aquatic animals. Ocean acidification (OA) and warming (OW) are expected to alter copper's bioavailability based on pH and temperature-sensitive effects; research on their effects on copper on marine organisms is still in its infancy. Therefore, under representative concentration pathways (RCP) 2.6, 4.5, and 8.5, we used the multiple linear regression-water quality criteria (MLR-WQC) method to assess the effects of OA and OW on the ecological risk posed by copper in the Ocean of East China (OEC), which includes the Bohai Sea, Yellow Sea, and East China Sea. The results showed that there was a positive correlation between temperature and copper toxicity, while there was a negative correlation between pH and copper toxicity. The short-term water quality criteria (WQC) values were 1.53, 1.41, 1.30 and 1.13 µg·L-1, while the long-term WQC values were 0.58, 0.48, 0.40 and 0.29 µg·L-1 for 2020, 2099-RCP2.6, 2099-RCP4.5 and 2099-RCP8.5, respectively. Cu in the OEC poses a moderate ecological risk. Under the current copper exposure situation, strict intervention (RCP2.6) only increases the ecological risk of copper exposure by 20 %, and no intervention (RCP8.5) will increase the ecological risk of copper exposure by nearly double. The results indicate that intervention on carbon emissions can slow down the rate at which OA and OW worsen the damage copper poses to marine creatures. This study can provide valuable information for a comprehensive understanding of the combined impacts of climate change and copper on marine organisms.

Bioinformatics-based dynamics of cuproptosis -related indicators in experimental silicosis.

Pneumoconiosis is one of the most serious occupational diseases worldwide. Silicosis due to prolonged inhalation of free silica dust during occupational activities is one of the main types. Cuproptosis is a newly discovered mode of programmed cell death characterized by the accumulation of free copper in the cell, which ultimately leads to cell death. Increased copper in the serum of silicosis patients, suggests that the development of silicosis is accompanied by changes in copper metabolism, but whether cuproptosis is involved in the progression of silicosis is actually to be determined. To test this hypothesis, we screened the genetic changes in patients with idiopathic fibrosis by bioinformatics methods and predicted and functionally annotated the cuproptosis-related genes among them. Subsequently, we established a mouse silicosis model and detected the concentration of copper ions and the activity of ceruloplasmin (CP) in serum, as well as changes of the concentration of copper and cuproptosis related genes in mouse lung tissues. We identified 9 cuproptosis-related genes among the differential genes in patients with IPF at different times and the tissue-specific expression levels of ferredoxin 1 (FDX1) and Lipoyl synthase (LIAS) proteins. Furthermore, serum CP activity and copper ion levels in silicosis mice were elevated on days 7th and 56th after silica exposure. The expression of CP in mouse lung tissue elevated at all stages after silica exposure. The mRNA level of FDX1 decreased on days 7th and 56th, and the protein level remained in accordance with the mRNA level on day 56th. LIAS and Dihydrolipoamide dehydrogenase (DLD) levels were downregulated at all times after silica exposure. In addition, Heatshockprotein70 (HSP70) expression was increased on day 56. In brief, our results demonstrate that there may be cellular cuproptosis during the development of experimental silicosis in mice and show synchronization with enhanced copper loading in mice.

Temperature influence on the sensitivity of Artemia franciscana to globally used pesticides - Oxyfluorfen and copper.

Climate change further the world's human population increase is a mainstream political issue, and it's critical to search for solutions to produce enough food to feed everyone. Pesticides and fertilizers have been used as an easy solution to prevent pests and increase food production. Nevertheless, their overuse has dangerous effects on the ecosystems and communities. Oxyfluorfen (Oxy) and copper (Cu) based formulations are used as pesticides and widely applied on agricultural fields for crop protection. However, they have shown negative effects on non-target species. So, this work proposes to: a)determine the lethal concentration of Oxy and Cu to the zooplankton, Artemia franciscana, at different temperatures (15 °C, 20 °C and 25 °C); b)understand the biochemical impacts of these chemicals at the different temperatures scenarios, on A. franciscana and c)evaluate the impact of the climate changes, particularly the temperature increase, on this species sensitivity to the tested pesticides. Acute and sub-lethal bioassays with Oxy and Cu were performed at different temperatures to determine the lethal concentration of each chemical and to understand the effects of the compounds at different temperatures on the biochemical profiles of A. franciscana. Results showed an increase in chemicals toxicity with the temperature, and Oxy was revealed to be more noxious to A. franciscana than Cu; at a biochemical level, significant differences were observed among temperatures, with the biggest differences between the organisms exposed to 15 °C and 25 °C. Overall, a decrease in fatty acids (FA) and sugars was observed with the increase in Cu and oxyfluorfen concentrations. Different trends were observed with temperature increase, with FA increase in the organisms exposed to Cu and the opposite was observed in the ones exposed to oxyfluorfen. Sugar content decreases in the organisms exposed to oxyfluorfen with temperature increase and showed a non-linear behaviour in the ones exposed to Control and Cu treatments.

Oenothera biennis with strong copper toxicity resistance enriches trace copper in seeds under copper pollution soil.

Excess copper (Cu) imparts negative effects on plant growth and productivity in soil. To develop the ability of O. biennis to govern pollution soil containing excessive Cu, we investigated seed germination, seedling growth, and seed yield. Furthermore, Cu content and the expression levels of Cu transport related genes in different tissues were measured under exogenous high concentration Cu. O. biennis seeds were sensitive to excess Cu, with an observed reduction in the germination rate, primary root length, fresh weight, and number of seeds germinated daily. Consecutive Cu stress did not cause fatal damage to evening primrose, yet it slowed down plant growth slightly by reducing the leaf water, chlorophyll, plant yield, and seed oil contents while increasing the soluble sugar, proline, malondialdehyde, and H2O2 contents. The Cu content in different organs of O. biennis was disrupted by excess Cu. In particular, the Cu content in O. biennis seeds and seed oil increased and subsequently decreased with the increase of exogenous Cu, reaching a peak under 600 mg·kg-1 consecutive Cu. Furthermore, the 4-month 900 mg·kg-1 Cu treatment did not induce the excessive accumulation of Cu in peels, seeds, and seed oil, maintaining the Cu content within the range required by the Chinese National Food Safety Standards. The treatment also resulted in an upregulation of Cu-uptake (ObCOPT5, ObZIP4, and ObYSL2) and vigorous efflux (ObHMA1) of transport genes, of which expression levels were significant positive correlation (p < 0.05) with the Cu content. Among all organs, the stem replaced the root as the organ exhibited the greatest ability to absorb and store Cu, and even the Cu transport genes could still function continuously in stem under excess Cu. This work identified a species that can tolerate high Cu content in soil while maintaining a high yield. Furthermore, the results revealed the enrichment of Cu to occur primarily in the O. biennis stem rather than the seeds and peel under excess Cu.

Copper enhances aggregational toxicity of mutant huntingtin in a Drosophila model of Huntington's Disease.

Huntington's disease (HD) is a progressive neurodegenerative disorder with clinical presentations of moderate to severe cognitive, motor, and psychiatric disturbances. HD is caused by the trinucleotide repeat expansion of CAG of the huntingtin (HTT) gene. The mutant HTT protein containing pathological polyglutamine (polyQ) extension is prone to misfolding and aggregation in the brain. It has previously been observed that copper and iron concentrations are increased in the striata of post-mortem human HD brains. Although it has been shown that the accumulation of mutant HTT protein can interact with copper, the underlying HD progressive phenotypes due to copper overload remains elusive. Here, in a Drosophila model of HD, we showed that copper induces dose-dependent aggregational toxicity and enhancement of Htt-induced neurodegeneration. Specifically, we found that copper increases mutant Htt aggregation, enhances the accumulation of Thioflavin S positive ß-amyloid structures within Htt aggregates, and consequently alters autophagy in the brain. Administration of copper chelator D-penicillamine (DPA) through feeding significantly decreases ß-amyloid aggregates in the HD pathological model. These findings reveal a direct role of copper in potentiating mutant Htt protein-induced aggregational toxicity, and further indicate the potential impact of environmental copper exposure in the disease onset and progression of HD.

The effect of calpain inhibitor-I on copper oxide nanoparticle-induced damage and cerebral ischemia-reperfusion in a rat model.

This study aimed to investigate the effects of the calpain inhibitor N-Acetyl-Leu-Leu-norleucinal (ALLN) on neuroapoptotic cell damage caused by Copper Oxide Nanoparticles (CuO-NP) and exacerbation of damage through brain ischemia/reperfusion (I/R) in a rat model. Male Wistar Albino rats (n=80) were divided into eight groups: Control, I/R, CuO-NP, CuO-NP+I/R, I/R+ALLN, CuO-NP+ALLN, CuO-NP+I/R+ALLN, and DMSO. Biochemical markers (MBP, S100B, NEFL, NSE, BCL-2, Cyt-C, Calpain, TNF-α, Caspase-3, MDA, and CAT) were measured in serum and brain tissue samples. Histological examinations (H&E staining), DNA fragmentation analysis (TUNEL) were performed, along with Caspase-3 assessment. The ALLN-treated groups exhibited significant improvements in biochemical markers and a remarkable reduction in apoptosis compared to the damaged groups (CuO-NP and I/R). H&E and Caspase-3 staining revealed damage-related morphological changes and reduced apoptosis in the ALLN-treated group. However, no differences were observed among the groups with TUNEL staining. The findings suggest that ALLN, as a calpain inhibitor, has potential implications for anti-apoptotic treatment, specifically in mitigating neuroapoptotic cell damage caused by CuO-NP and I/R.

Co-exposure of polystyrene nanoplastics and copper induces development toxicity and intestinal mitochondrial dysfunction in vivo and in vitro.

Nanoplastics (NPs) have raised concerns about the combined toxicity to living organisms due to their ability to adsorb heavy metals. There is still uncertainty, however, whether NPs combined with heavy metals exert adverse effects on intestinal microenvironment, especially the intestinal cells and microbiota. Herein, the combined effects of 500 nm spherical-shaped polystyrene nanoplastics (PSNPs) and copper ions (Cu2+) on intestinal cells and gut microbiota were assessed using HCT-116 cells and zebrafish models. The combined exposure of PSNPs (10 mg/L) and Cu2+ (0.5 mg/L) induced more severer hatching interference of zebrafish embryos, deformation, and mortality. In larval stage, PSNPs (10 mg/L) accumulated and carried more Cu2+ in the gastrointestinal tract (GIT) of zebrafish after co-exposure for 5 days. Excessive neutrophil recruitment and oxidative stress in GIT of zebrafish larvae were observed. The mechanism of the combined toxicity was revealed by transmission electron microscopy (TEM) showing the injuries of GIT, transcriptome and 16S rDNA gene sequencing showing the toxicity pathways, including oxidative phosphorylation and respiratory electron transport chain, as well as microbial community analysis showing the induced microbiota dysbiosis. In vitro tests using HCT-116 cells showed that PSNPs (10 mg/L) and Cu2+ (0.5 mg/L) increased cell death while decreasing ATP concentration and mitochondrial membrane potential after 48 h exposure. These findings may provide new insights into the combined toxicity of nanoplastics and heavy metals in the intestinal microenvironment.

Interplay between diphenyl diselenide and copper: Impact on D. melanogaster survival, behavior, and biochemical parameters.

Copper (Cu2+) is a biologically essential element that participates in numerous physiological processes. However, elevated concentrations of copper have been associated with cellular oxidative stress and neurodegenerative diseases. Organo­selenium compounds such as diphenyl diselenide (DPDS) have in vitro and in vivo antioxidant properties. Hence, we hypothesized that DPDS may modulate the toxicity of Cu2+ in Drosophila melanogaster. The acute effects (4 days of exposure) caused by a high concentration of Cu2+ (3 mM) were studied using endpoints of toxicity such as survival and behavior in D. melanogaster. The potential protective effect of low concentration of DPDS (20 µM) against Cu2+ was also investigated. Adult flies aged 1-5 days post-eclosion (both sexes) were divided into four groups: Control, DPDS (20 µM), CuSO4 (3 mM), and the combined exposure of DPDS (20 µM) and CuSO4 (3 mM). Survival, biochemical, and behavioral parameters were determined. Co-exposure of DPDS and CuSO4 increased acetylcholinesterase (AChE) activity and the generation of reactive oxygen species (ROS as determined by DFCH oxidation). Contrary to our expectation, the co-exposure reduced survival, body weight, locomotion, catalase activity, and cell viability in relation to control group. Taken together, DPDS potentiated the Cu2+ toxicity.

Nitrate modulates the physiological tolerance responses of the halophytic species Sarcocornia fruticosa to copper excess.

Coexistence impact of pollutants of different nature on halophytes tolerance to metal excess has not been thoroughly examined, and plant functional responses described so far do not follow a clear pattern. Using the Cu-tolerant halophyte Sarcocornia fruticosa as a model species, we conducted a greenhouse experiment to evaluate the impact of two concentration of copper (0 and 12 mM CuSO4) in combination with three nitrate levels (2, 14 and 50 mM KNO3) on plant growth, photosynthetic apparatus performance and ROS-scavenging enzymes system. The results revealed that S. fruticosa was able to grow adequately even when exposed to high concentrations of copper and nitrate. This response was linked to the plant capacity to uptake and retain a large amount of copper in its roots (up to 1500 mg kg-1 Cu), preventing its transport to aerial parts. This control of translocation was further magnified with nitrate concentration increment. Likewise, although Cu excess impaired S. fruticosa carbon assimilation capacity, the plant was able to downregulate its light-harvesting complexes function, as indicated its lowers ETR values, especially at 12 mM Cu + 50 mM NO3. This downregulation would contribute to avoid excess energy absorption and transformation. In addition, this strategy of avoiding excess energy was accompanied by the upregulation of all ROS-scavenging enzymes, a response that was further enhanced by the increase in nitrate concentration. Therefore, we conclude that the coexistence of nitrate would favor S. fruticosa tolerance to copper excess, and this effect is mediated by the combined activation of several tolerance mechanisms.