| 1. |
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| 2. |
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| 3. |
- Almamoun, Radwa, et al.
(författare)
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Mechanistic screening of reproductive toxicity in a novel 3D testicular co-culture model shows significant impairments following exposure to low-dibutyl phthalate concentrations
- 2024
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Ingår i: Archives of Toxicology. - 0340-5761 .- 1432-0738.
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Tidskriftsartikel (refereegranskat)abstract
- To improve the mechanistic screening of reproductive toxicants in chemical-risk assessment and drug development, we have developed a three-dimensional (3D) heterogenous testicular co-culture model from neonatal mice. Di-n-butyl phthalate (DBP), an environmental contaminant that can affect reproductive health negatively, was used as a model compound to illustrate the utility of the in vitro model. The cells were treated with DBP (1 nM to 100 µM) for 7 days. Automated high-content imaging confirmed the presence of cell-specific markers of Leydig cells (CYP11A1 +), Sertoli cells (SOX9 +), and germ cells (DAZL +). Steroidogenic activity of Leydig cells was demonstrated by analyzing testosterone levels in the culture medium. DBP induced a concentration-dependent reduction in testosterone levels and decreased the number of Leydig cells compared to vehicle control. The levels of steroidogenic regulator StAR and the steroidogenic enzyme CYP11A1 were decreased already at the lowest DBP concentration (1 nM), demonstrating upstream effects in the testosterone biosynthesis pathway. Furthermore, exposure to 10 nM DBP decreased the levels of the germ cell-specific RNA binding protein DAZL, central for the spermatogenesis. The 3D model also captured the development of the Sertoli cell junction proteins, N-cadherin and Zonula occludens protein 1 (ZO-1), critical for the blood–testis barrier. However, DBP exposure did not significantly alter the cadherin and ZO-1 levels. Altogether, this 3D in vitro system models testicular cellular signaling and function, making it a powerful tool for mechanistic screening of developmental testicular toxicity. This can open a new avenue for high throughput screening of chemically-induced reproductive toxicity during sensitive developmental phases.
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| 4. |
- Andersson, Helén, 1982-, et al.
(författare)
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Proangiogenic Effects of Environmentally Relevant Levels of Bisphenol A in Human Primary Endothelial Cells
- 2012
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Ingår i: Archives of Toxicology. - : Springer Science and Business Media LLC. - 0340-5761 .- 1432-0738. ; 86:3, s. 465-474
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Tidskriftsartikel (refereegranskat)abstract
- Bisphenol A (BPA) is widely used in the manufacturing of consumer products such as plastic food containers and food cans. Experimental studies suggest a relationship between exposure to BPA and changes in metabolic processes and reproductive organs. Also, epidemiological studies report an association between elevated exposure to BPA and cardiovascular disease and diabetes. Although alterations in the vascular endothelium are implicated in pathological conditions associated with BPA, little is known about the effects of BPA in the human endothelium. This study aimed to investigate the effects of 0.1 nM-1 μM of BPA on selected biomarkers of endothelial dysfunction, inflammation, and angiogenesis in human umbilical vein endothelial cells (HUVEC). The mRNA expression of biomarkers was assayed using qRT-PCR, and the production of nitric oxide and reactive oxygen species was measured using the H(2)DCFDA and the DAF-FM assays. The effect of BPA on phosphorylated eNOS was examined using Western blot and immunofluorescence, and the endothelial tube formation assay was used to investigate in vitro angiogenesis. BPA (≤1 μM) increased the mRNA expression of the proangiogenic genes VEGFR-2, VEGF-A, eNOS, and Cx43 and increased the production of nitric oxide in HUVEC. Furthermore, BPA increased the expression of phosphorylated eNOS and endothelial tube formation in HUVEC. These studies demonstrate that environmentally relevant levels of BPA have direct proangiogenic effects on human primary endothelial cells in vitro suggesting that the human endothelium may be an important target for BPA.
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| 5. |
- Andronis, Christos, et al.
(författare)
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Molecular basis of mood and cognitive adverse events elucidated via a combination of pharmacovigilance data mining and functional enrichment analysis
- 2020
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Ingår i: Archives of Toxicology. - : Springer Nature. - 0340-5761 .- 1432-0738. ; 94:8, s. 2829-2845
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Tidskriftsartikel (refereegranskat)abstract
- Drug-induced Mood- and Cognition-related adverse events (MCAEs) are often only detected during the clinical trial phases of drug development, or even after marketing, thus posing a major safety concern and a challenge for both pharmaceutical companies and clinicians. To fill some gaps in the understanding and elucidate potential biological mechanisms of action frequently associated with MCAEs, we present a unique workflow linking observational population data with the available knowledge at molecular, cellular, and psychopharmacology levels. It is based on statistical analysis of pharmacovigilance reports and subsequent signaling pathway analyses, followed by evidence-based expert manual curation of the outcomes. Our analysis: (a) ranked pharmaceuticals with high occurrence of such adverse events (AEs), based on disproportionality analysis of the FDA Adverse Event Reporting System (FAERS) database, and (b) identified 120 associated genes and common pathway nodes possibly underlying MCAEs. Nearly two-thirds of the identified genes were related to immune modulation, which supports the critical involvement of immune cells and their responses in the regulation of the central nervous system function. This finding also means that pharmaceuticals with a negligible central nervous system exposure may induce MCAEs through dysregulation of the peripheral immune system. Knowledge gained through this workflow unravels putative hallmark biological targets and mediators of drug-induced mood and cognitive disorders that need to be further assessed and validated in experimental models. Thereafter, they can be used to substantially improve in silico/in vitro/in vivo tools for predicting these adversities at a preclinical stage.
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| 6. |
- Annas, Anita, et al.
(författare)
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Induction of ethoxyresorufin O-deethylase (EROD) and endothelial activation of the heterocyclic amine Trp-P-1 in bird embryo hearts
- 1998
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Ingår i: Archives of Toxicology. - : Springer Science and Business Media LLC. - 0340-5761 .- 1432-0738. ; 72:7, s. 402-410
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Tidskriftsartikel (refereegranskat)abstract
- The xenobiotic-metabolizing activity of avian heart was investigated in chicken and Eider duck embryos exposed to aryl hydrocarbon (Ah) receptor agonists in ovo. Both beta-naphthoflavone (BNF) and 3,3',4,4',5-pentachlorobiphenyl (PCB 126) induced 7-ethoxyresorufin O-deethylase (EROD) activities in chicken embryo hearts whereas Eider duck embryos only responded to BNF. The differential responses of chicken and Eider duck embryos were used to examine the involvement of Ah receptor-mediated enzyme induction in the activation of the environmental and food mutagen 3-amino- 1,4-dimethyl-5H-pyrido[4,3-b]indole (Trp-P-1). As determined by light microscopic autoradiography, there was a highly selective binding of non-extractable 3H-Trp-P-1-derived radioactivity in endothelial cells of large vessels and capillaries in hearts of BNF- and PCB 126-treated chicken embryos. No binding occurred at these sites in vehicle-treated controls. There was also a strong endothelial binding of 3H-Trp-P-1 in hearts of BNF-treated Eider duck embryos whereas no binding occurred in hearts of PCB 126-treated Eider duck embryos. A positive correlation between induction of EROD activity and covalent binding of 3H-Trp-P-1 to protein in heart homogenates from BNF- and PCB 126-treated chicken and Eider duck embryos was also observed. The results suggest a cytochrome P450 1A (CYP1A)-mediated activation of Trp-P-1 in avian heart endothelial cells although involvement of other Ah receptor-regulated enzymes is also possible. We propose that heart endothelial cells may be targets for bioactivation and toxicity of environmental contaminants in birds exposed to Ah receptor agonists.
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| 7. |
- Arlt, Volker M., et al.
(författare)
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Impact of genetic modulation of SULT1A enzymes on DNA adduct formation by aristolochic acids and 3-nitrobenzanthrone
- 2017
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Ingår i: Archives of Toxicology. - : Springer Science and Business Media LLC. - 0340-5761 .- 1432-0738. ; 91:4, s. 1957-1975
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Tidskriftsartikel (refereegranskat)abstract
- Exposure to aristolochic acid (AA) causes aristolochic acid nephropathy (AAN) and Balkan endemic nephropathy (BEN). Conflicting results have been found for the role of human sulfotransferase 1A1 (SULT1A1) contributing to the metabolic activation of aristolochic acid I (AAI) in vitro. We evaluated the role of human SULT1A1 in AA bioactivation in vivo after treatment of transgenic mice carrying a functional human SULT1A1-SULT1A2 gene cluster (i.e. hSULT1A1/2 mice) and Sult1a1(−/−) mice with AAI and aristolochic acid II (AAII). Both compounds formed characteristic DNA adducts in the intact mouse and in cytosolic incubations in vitro. However, we did not find differences in AAI-/AAII-DNA adduct levels between hSULT1A1/2 and wild-type (WT) mice in all tissues analysed including kidney and liver despite strong enhancement of sulfotransferase activity in both kidney and liver of hSULT1A1/2 mice relative to WT, kidney and liver being major organs involved in AA metabolism. In contrast, DNA adduct formation was strongly increased in hSULT1A1/2 mice compared to WT after treatment with 3-nitrobenzanthrone (3-NBA), another carcinogenic aromatic nitro compound where human SULT1A1/2 is known to contribute to genotoxicity. We found no differences in AAI-/AAII-DNA adduct formation in Sult1a1(−/−) and WT mice in vivo. Using renal and hepatic cytosolic fractions of hSULT1A1/2, Sult1a1(−/−) and WT mice, we investigated AAI-DNA adduct formation in vitro but failed to find a contribution of human SULT1A1/2 or murine Sult1a1 to AAI bioactivation. Our results indicate that sulfo-conjugation catalysed by human SULT1A1 does not play a role in the activation pathways of AAI and AAII in vivo, but is important in 3-NBA bioactivation.
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| 8. |
- Asp, Vendela, et al.
(författare)
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Cytotoxicity and decreased corticosterone production in adrenocortical Y-1 cells by 3-methylsulfonyl-DDE and structurally related molecules
- 2009
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Ingår i: Archives of Toxicology. - : Springer Science and Business Media LLC. - 0340-5761 .- 1432-0738. ; 83:4, s. 389-396
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Tidskriftsartikel (refereegranskat)abstract
- The persistent environmental pollutant 3-methylsulfonyl-DDE (3-MeSO2-DDE) undergoes bioactivation by cytochrome P450 11B1 (CYP11B1) in the adrenal cortex of several animal species in vivo and causes decreased glucocorticoid production and cell death in the zona fasciculata. This study presents extended investigations of the cytotoxic and endocrine disrupting effects of 3-MeSO2-DDE and some structurally related molecules in the mouse adrenocortical cell line Y-1. Both 3-MeSO2-DDE and, to a lesser extent, 3,3'(bis)-MeSO2-DDE decreased corticosterone production and produced CYP11B1-dependent cytotoxicity in Y-1 cells. Neither 2-MeSO2-DDE nor p,p'-DDE had any significant effect on either cell viability or corticosterone production, indicating that the presence and position of the methylsulfonyl moiety of 3-MeSO2-DDE is crucial for its biological activity. The adrenocortical toxicant o,p'-DDD decreased corticosterone production but was not cytotoxic in this cell line. None of the compounds altered Cyp11b1 gene expression, indicating that 3-MeSO2-DDE inhibits CYP11B1 activity on the protein level.
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| 9. |
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| 10. |
- Basaure, P., et al.
(författare)
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Learning, memory and the expression of cholinergic components in mice are modulated by the pesticide chlorpyrifos depending upon age at exposure and apolipoprotein E (APOE) genotype
- 2019
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Ingår i: Archives of Toxicology. - : Springer Science and Business Media LLC. - 0340-5761 .- 1432-0738. ; 93:3, s. 693-707
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Tidskriftsartikel (refereegranskat)abstract
- Polymorphisms of the apolipoprotein E (APOE) gene differentially affect neurobiological functions and cognitive performance and confer different vulnerabilities to subclinical exposures to chlorpyrifos (CPF), a pesticide used worldwide. The data reported on this topic suggest a complex interaction between cholinergic signaling and the APOE genotype. To gain greater functional insight into this interaction, we evaluated spatial learning and memory and hippocampal cholinergic expression in young apoE3 and apoE4 transgenic mice exposed to CPF. Male and female mice were exposed to CPF at 0 or 1 mg/kg on postnatal days 10-15 and then, exposed to CPF at 0 or 2 mg/kg for 60 days at 5 months of age. At 6 months of age, mice were tested for spatial skills in a Barnes maze. At the end of the task, animals were killed and gene expression of cholinergic components was assessed in the hippocampus. Our results show that apoE4 female mice performed worse in the spatial task, while postnatal CPF impaired escape strategies and spatial memory in apoE3 mice. In turn, CPF in adulthood improved spatial abilities in apoE4 female mice. Regarding gene expression, choline acetyltransferase (ChAT) and vesicular acetylcholine transporter (VAChT) expression were increased in apoE4 mice. Postnatal exposure to CPF increased ChAT mRNA levels in apoE4 mice, whereas adult exposure to CPF induced changes in acetylcholinesterase-S, alpha 7- and alpha 4-subunit nicotinic receptor expression in apoE4 females. The current findings provide new insights into APOE-dependent cholinergic signaling, which directly affects the response to CPF cholinergic insult, especially in APOE4 subjects.
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| 11. |
- Behr, A. C., et al.
(författare)
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Impairment of bile acid metabolism by perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) in human HepaRG hepatoma cells
- 2020
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Ingår i: Archives of Toxicology. - : Springer Science and Business Media LLC. - 0340-5761 .- 1432-0738. ; 94, s. 1673-1686
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Tidskriftsartikel (refereegranskat)abstract
- Perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) are man-made chemicals that are used for the fabrication of many products with water- and dirt-repellent properties. The toxicological potential of both substances is currently under debate. In a recent Scientific Opinion, the European Food Safety Authority (EFSA) has identified increased serum total cholesterol levels in humans as one major critical effect being associated with exposure to PFOA or PFOS. In animal studies, both substances induced a decrease of serum cholesterol levels, and the underlying molecular mechanism(s) for these opposed effects are unclear so far. In the present study, we examined the impact of PFOA and PFOS on cholesterol homoeostasis in the human HepaRG cell line as a model for human hepatocytes. Cholesterol levels in HepaRG cells were not affected by PFOA or PFOS, but both substances strongly decreased synthesis of a number of bile acids. The expression of numerous genes whose products are involved in synthesis, metabolism and transport of cholesterol and bile acids was strongly affected by PFOA and PFOS at concentrations above 10 mu M. Notably, both substances led to a strong decrease of CYP7A1, the key enzyme catalyzing the rate-limiting step in the synthesis of bile acids from cholesterol, both at the protein level and at the level of gene expression. Moreover, both substances led to a dilatation of bile canaliculi that are formed by differentiated HepaRG cells in vitro. Similar morphological changes are known to be induced by cholestatic agents in vivo. Thus, the strong impact of PFOA and PFOS on bile acid synthesis and bile canalicular morphology in our in vitro experiments may allow the notion that both substances have a cholestatic potential that is connected to the observed increased serum cholesterol levels in humans in epidemiological studies.
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| 12. |
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| 14. |
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| 15. |
- Carlsson, Carina, et al.
(författare)
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Olfactory mucosal toxicity screening and multivariate QSAR modeling for chlorinated benzene derivatives
- 2004
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Ingår i: Archives of Toxicology. - : Springer Science and Business Media LLC. - 0340-5761 .- 1432-0738. ; 78:12, s. 706-715
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Tidskriftsartikel (refereegranskat)abstract
- The olfactory mucosa (OM) is an important target for metabolism-dependent toxicity of drugs and chemicals. Several OM toxicants share a 2,6-dichlorinated benzene structure. The herbicides dichlobenil (2,6-dichlorobenzonitrile) and chlorthiamide (2,6-dichlorothiobenzamide) and the environmental dichlobenil metabolite 2,6-dichlorobenzamide all induce toxicity in the OM following covalent binding in the Bowmans glands. In addition, we have shown that 2,6-dichlorophenyl methylsulfone targets the Bowmans glands and is probably the most potent OM toxicant so far described. These findings suggest that the 2,6-positioning of chlorines in combination with an electron-withdrawing group in the primary position of the benzene ring is an arrangement that facilitates OM toxicity. This study examined the physicochemical characteristics of the 2,6-dichlorinated OM toxicants. A number of 2,6-dichlorinated benzene derivatives with various types of substituents in primary position were tested for OM toxicity in mice. In addition, some other 2,6- and 2,5-substituted benzene derivatives were examined. Two novel OM toxicants, 2,6-dichlorobenzaldehyde oxime and 2,6-dichloronitrobenzene, were identified. By the use of partial least squares projection to latent structures with discriminant analysis (PLS-DA) a preliminary quantitative structure-activity relationship (QSAR) model was built also using reported OM toxicity data. Physicochemical properties positively correlated with olfactory mucosal toxicity were identified as molecular dipolar momentum and the electronic properties of the substituent. Inversely correlated descriptors were variables describing the hydrophobicity, electronic properties of the molecule such as electron affinity and the electronic charge on the primary carbon. In conclusion, this preliminary PLS-DA model shows that a 2,6-dichlorinated benzene derivative with a large, polar, and strong electron-withdrawing substituent in the primary position has the potential of being a potent OM toxicant in mice.
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| 16. |
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| 17. |
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| 18. |
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| 19. |
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| 20. |
- Delp, Johannes, et al.
(författare)
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Development of a neurotoxicity assay that is tuned to detect mitochondrial toxicants
- 2019
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Ingår i: Archives of Toxicology. - : Springer Science and Business Media LLC. - 0340-5761 .- 1432-0738. ; 93:6, s. 1585-1608
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Tidskriftsartikel (refereegranskat)abstract
- Many neurotoxicants affect energy metabolism in man, but currently available test methods may still fail to predict mito- and neurotoxicity. We addressed this issue using LUHMES cells, i.e., human neuronal precursors that easily differentiate into mature neurons. Within the NeuriTox assay, they have been used to screen for neurotoxicants. Our new approach is based on culturing the cells in either glucose or galactose (Glc-Gal-NeuriTox) as the main carbohydrate source during toxicity testing. Using this Glc-Gal-NeuriTox assay, 52 mitochondrial and non-mitochondrial toxicants were tested. The panel of chemicals comprised 11 inhibitors of mitochondrial respiratory chain complex I (cI), 4 inhibitors of cII, 8 of cIII, and 2 of cIV; 8 toxicants were included as they are assumed to be mitochondrial uncouplers. In galactose, cells became more dependent on mitochondrial function, which made them 2-3 orders of magnitude more sensitive to various mitotoxicants. Moreover, galactose enhanced the specific neurotoxicity (destruction of neurites) compared to a general cytotoxicity (plasma membrane lysis) of the toxicants. The Glc-Gal-NeuriTox assay worked particularly well for inhibitors of cI and cIII, while the toxicity of uncouplers and non-mitochondrial toxicants did not differ significantly upon glucose <-> galactose exchange. As a secondary assay, we developed a method to quantify the inhibition of all mitochondrial respiratory chain functions/complexes in LUHMES cells. The combination of the Glc-Gal-NeuriTox neurotoxicity screening assay with the mechanistic follow up of target site identification allowed both, a more sensitive detection of neurotoxicants and a sharper definition of the mode of action of mitochondrial toxicants.
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| 21. |
- Delp, Johannes, et al.
(författare)
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Neurotoxicity and underlying cellular changes of 21 mitochondrial respiratory chain inhibitors
- 2021
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Ingår i: Archives of Toxicology. - : Springer. - 0340-5761 .- 1432-0738. ; 95:2, s. 591-615
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Tidskriftsartikel (refereegranskat)abstract
- Inhibition of complex I of the mitochondrial respiratory chain (cI) by rotenone and methyl-phenylpyridinium (MPP +) leads to the degeneration of dopaminergic neurons in man and rodents. To formally describe this mechanism of toxicity, an adverse outcome pathway (AOP:3) has been developed that implies that any inhibitor of cI, or possibly of other parts of the respiratory chain, would have the potential to trigger parkinsonian motor deficits. We used here 21 pesticides, all of which are described in the literature as mitochondrial inhibitors, to study the general applicability of AOP:3 or of in vitro assays that are assessing its activation. Five cI, three complex II (cII), and five complex III (cIII) inhibitors were characterized in detail in human dopaminergic neuronal cell cultures. The NeuriTox assay, examining neurite damage in LUHMES cells, was used as in vitro proxy of the adverse outcome (AO), i.e., of dopaminergic neurodegeneration. This test provided data on whether test compounds were unspecific cytotoxicants or specifically neurotoxic, and it yielded potency data with respect to neurite degeneration. The pesticide panel was also examined in assays for the sequential key events (KE) leading to the AO, i.e., mitochondrial respiratory chain inhibition, mitochondrial dysfunction, and disturbed proteostasis. Data from KE assays were compared to the NeuriTox data (AO). The cII-inhibitory pesticides tested here did not appear to trigger the AOP:3 at all. Some of the cI/cIII inhibitors showed a consistent AOP activation response in all assays, while others did not. In general, there was a clear hierarchy of assay sensitivity: changes of gene expression (biomarker of neuronal stress) correlated well with NeuriTox data; mitochondrial failure (measured both by a mitochondrial membrane potential-sensitive dye and a respirometric assay) was about 10-260 times more sensitive than neurite damage (AO); cI/cIII activity was sometimes affected at > 1000 times lower concentrations than the neurites. These data suggest that the use of AOP:3 for hazard assessment has a number of caveats: (i) specific parkinsonian neurodegeneration cannot be easily predicted from assays of mitochondrial dysfunction; (ii) deriving a point-of-departure for risk assessment from early KE assays may overestimate toxicant potency.
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| 22. |
- Deventer, Marie H., et al.
(författare)
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Off-target activity of NBOMes and NBOMe analogs at the mu opioid receptor
- 2023
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Ingår i: Archives of Toxicology. - : SPRINGER HEIDELBERG. - 0340-5761 .- 1432-0738. ; 97:5, s. 1367-1384
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Tidskriftsartikel (refereegranskat)abstract
- New psychoactive substances (NPS) are introduced on the illicit drug market at a rapid pace. Their molecular targets are often inadequately elucidated, which contributes to the delayed characterization of their pharmacological effects. Inspired by earlier findings, this study set out to investigate the mu opioid receptor (MOR) activation potential of a large set of psychedelics, substances which typically activate the serotonin (5-HT2A) receptor as their target receptor. We observed that some substances carrying the N-benzyl phenethylamine (NBOMe) structure activated MOR, as confirmed by both the NanoBiT (R) beta arr2 recruitment assay and the G protein-based AequoScreen (R) Ca2+ release assay. The use of two orthogonal systems proved beneficial as some aspecific, receptor independent effects were found for various analogs when using the Ca2+ release assay. The specific off-target effects at MOR could be blocked by the opioid antagonist naloxone, suggesting that these NBOMes occupy the same common opioid binding pocket as conventional opioids. This was corroborated by molecular docking, which revealed the plausibility of multiple interactions of 25I-NBOMe with MOR, similar to those observed for opioids. Additionally, structure-activity relationship findings seen in vitro were rationalized in silico for two 25I-NBOMe isomers. Overall, as MOR activity of these psychedelics was only noticed at high concentrations, we consider it unlikely that for the tested compounds there will be a relevant opioid toxicity in vivo at physiologically relevant concentrations. However, small modifications to the original NBOMe structure may result in a panel of more efficacious and potent MOR agonists, potentially exhibiting a dual MOR/5-HT2A activation potential.
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| 23. |
- Dharpure, Rupal, et al.
(författare)
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In silico analysis decodes transthyretin (TTR) binding and thyroid disrupting effects of per- and polyfluoroalkyl substances (PFAS)
- 2023
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Ingår i: Archives of Toxicology. - : Springer. - 0340-5761 .- 1432-0738. ; 97:3, s. 755-768
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Tidskriftsartikel (refereegranskat)abstract
- Transthyretin (TTR) is a homo-tetramer protein involved in the transport of thyroid hormone (thyroxine; T4) in the plasma and cerebrospinal fluid. Many pollutants have been shown to bind to TTR, which could be alarming as disruption in the thyroid hormone system can lead to several physiological problems. It is also indicated that the monomerization of tetramer and destabilization of monomer can lead to amyloidogenesis. Many compounds are identified that can bind to tetramer and stabilize the tetramer leading to the inhibition of amyloid fibril formation. Other compounds are known to bind tetramer and induce amyloid fibril formation. Among the pollutants, per- and polyfluoroalkyl substances (PFAS) are known to disrupt the thyroid hormone system. The molecular mechanisms of thyroid hormone disruption could be diverse, as some are known to bind with thyroid hormone receptors, and others can bind to membrane transporters. Binding to TTR could also be one of the important pathways to alter thyroid signaling. However, the molecular interactions that drive thyroid-disrupting effects of long-chain and short-chain PFASs are not comprehensively understood at the molecular level. In this study, using a computational approach, we show that carbon chain length and functional group in PFASs are structural determinants, in which longer carbon chains of PFASs and sulfur-containing PFASs favor stronger interactions with TTR than their shorter-chained counterparts. Interestingly, short-chain PFAS also showed strong binding capacity, and the interaction energy for some was as close to the longer-chain PFAS. This suggests that short-chain PFASs are not completely safe, and their use and build-up in the environment should be carefully regulated. Of note, TTR homologs analysis suggests that thyroid-disrupting effects of PFASs could be most likely translated to TTR-like proteins and other species.
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| 24. |
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| 25. |
- Engström, Karin, et al.
(författare)
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Transcriptomics and methylomics of CD4-positive T cells in arsenic-exposed women
- 2017
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Ingår i: Archives of Toxicology. - : Springer Science and Business Media LLC. - 0340-5761 .- 1432-0738. ; 91:5, s. 2067-2078
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Tidskriftsartikel (refereegranskat)abstract
- Arsenic, a carcinogen with immunotoxic effects, is a common contaminant of drinking water and certain food worldwide. We hypothesized that chronic arsenic exposure alters gene expression, potentially by altering DNA methylation of genes encoding central components of the immune system. We therefore analyzed the transcriptomes (by RNA sequencing) and methylomes (by target-enrichment next-generation sequencing) of primary CD4-positive T cells from matched groups of four women each in the Argentinean Andes, with fivefold differences in urinary arsenic concentrations (median concentrations of urinary arsenic in the lower- and high-arsenic groups: 65 and 276 mu g/l, respectively). Arsenic exposure was associated with genome-wide alterations of gene expression; principal component analysis indicated that the exposure explained 53% of the variance in gene expression among the top variable genes and 19% of 28,351 genes were differentially expressed (false discovery rate < 0.05) between the exposure groups. Key genes regulating the immune system, such as tumor necrosis factor alpha and interferon gamma, as well as genes related to the NF-kappa-beta complex, were significantly downregulated in the high-arsenic group. Arsenic exposure was associated with genome-wide DNA methylation; the high-arsenic group had 3% points higher genome-wide full methylation (> 80% methylation) than the lower-arsenic group. Differentially methylated regions that were hyper-methylated in the high-arsenic group showed enrichment for immune-related gene ontologies that constitute the basic functions of CD4-positive T cells, such as isotype switching and lymphocyte activation and differentiation. In conclusion, chronic arsenic exposure from drinking water was related to changes in the transcriptome and methylome of CD4-positive T cells, both genome wide and in specific genes, supporting the hypothesis that arsenic causes immunotoxicity by interfering with gene expression and regulation.
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| 26. |
- Engwall, Magnus, 1965-, et al.
(författare)
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Ethoxyresorufin O-deethylase (EROD) and aryl hydrocarbon hydroxylase (AHH)-inducing potency and lethality of chlorinated naphthalenes in chicken (Gallus domesticus) and eider duck (Somateria mollissima) embryos
- 1994
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Ingår i: Archives of Toxicology. - : Springer Science and Business Media LLC. - 0340-5761 .- 1432-0738. ; 68:1, s. 37-42
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Tidskriftsartikel (refereegranskat)abstract
- The 7-ethoxyresorufin O-deethylase (EROD)- and aryl hydrocarbon hydroxylase (AHH)-inducing potencies and lethalities of a technical preparation of polychlorinated naphthalenes (PCNs) (Halowax 1014, approx imate congener ratio: 20% tetrachloronaphthalenes, 40% pentachloronaphthalenes, 40% hexachloronaphthalenes), a mixture of 50% 1,2,3,5,6,7-hexachloronaphthalene and 50% 1,2,3,4,6,7-hexachloronaphthalene (HxCN-mix), and 1,2,3,4,5,6,7-heptachloronaphthalene (HpCN) were studied in chicken (Gallus domesticus) and elder duck (Somateria mollissima) embryos. Mortality and hepatic EROD activity were determined on day 10 of incubation in chicken embryos exposed to various doses of the PCNs via the air-sacs of the eggs on day 7. The HxCN-mix and Halowax 1014 proved to have both embryolethal and EROD-inducing properties, while the HpCN had low EROD-inducing potency and embryolethality. ED(50) values for EROD induction by the HxCN-mix and Halowax 1014 were estimated to be 0.06 mg/kg egg and 0.2 mg/kg egg, respectively. Fifty percent of the chicken embryos died (6/12) when given 3.0 mg/kg of the HxCN-mix while a similar dose of Halowax 1014 caused mortality in 4 out of 12 chicken embryos. The dose-response curve for EROD induction by Halowax 1014 exhibited a decline after the maximal level was reached. When Halowax 1014 (1.0 mg/kg, egg) was coinjected with 3,3',4,4',5-pentachlorobiphenyl (PCB IUPAC #126) (0.1 mu g/kg egg) no additive effects on EROD activity were found, but when the same dose of Halowax 1014 was coinjected with a dose of PCB #126, known to cause maximal induction (1.0 mu g/kg egg), the resulting EROD activity was lower than that caused solely by 1.0 mu g PCB #126/kg egg. These findings indicate that Halowax 1014 has both EROD-inducing and EROD-inhibiting properties. Mortality and EROD and AHH activities were determined on day 18 (chicken) or day 24 (elder) of incubation in embryos exposed to 1.0 mg/kg egg via the yolk-sac on day 4 (chicken) or day 5 (elder). The HxCN-mix and Halowax 1014 induced AHH and EROD in both chicken and elder, but the induction rates were higher in the elder embryos. The HxCN-mix and Halowax 1014 caused degenerative hepatic lesions and pericardial oedema in the chicken embryos but not in the elder embryos. The most toxic PCNs tested (the HxCN-mix and Halowax 1014) were approximately of the same EROD-inducing potency as previously found for the most toxic mono-ortho-chlorinated biphenyls (Brunstrom 1990), and 1000 times less toxic and potent as EROD inducers compared with PCB #126 (Brunstrom and Andersson 1988). HpCN was considerably less toxic and exhibited a low EROD-inducing potency. The chicken embryos were more sensitive to the hepatotoxic effects produced by Halowax 1014 and the HxCN-mix than the elder duck embryos, while the elder embryos were more responsive in terms of EROD and AHH induction. The two HxCNs studied usually make up approximately 1% of the total quantity of PCNs present in Halowax 1014 [when determined with gas chromatography (flame ionization detection)]. Therefore, the relatively high toxic potency of Halowax 1014 cannot be explained by its content of the two HxCNs.
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| 27. |
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| 28. |
- Fex, G, et al.
(författare)
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Low serum concentration of all-trans and 13-cis retinoic acids in patients treated with phenytoin, carbamazepine and valproate. Possible relation to teratogenicity
- 1995
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Ingår i: Archives of Toxicology. - : Springer Science and Business Media LLC. - 0340-5761 .- 1432-0738. ; 69:8, s. 572-574
-
Tidskriftsartikel (refereegranskat)abstract
- All-trans retinoic acid deficiency resulting from ethanol's interference with the synthesis of all-trans retinoic acid from retinol was recently suggested to cause the malformations of the fetal alcohol syndrome. Phenytoin, carbamazepine and valproate, might be teratogenic because they lower the concentration of all-trans retinoic acid in serum, by inducing the enzyme systems in the liver responsible for the metabolism of the all-trans retinoic acid, or by other mechanisms. Here we show, that in patients given therapeutic doses of phenytoin, carbamazepine and valproate, serum all-trans and 13-cis retinoic acid concentrations are indeed significantly lowered. We propose that drugs with this ability should be considered as potential teratogens.
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| 29. |
- Franzén, Anna, et al.
(författare)
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Toxicant-induced ER-stress and Caspase Activation in the Olfactory Mucosa
- 2005
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Ingår i: Archives of Toxicology. - : Springer Science and Business Media LLC. - 0340-5761 .- 1432-0738. ; 79:10, s. 561-570
-
Tidskriftsartikel (refereegranskat)abstract
- The potent olfactory toxicant 2,6-dichlorophenyl methylsulphone (2,6-diClPh-MeSO(2)) induces rapid cell death and long-term metaplastic changes in the olfactory regions of rodents. The damage is related to a tissue-specific and extensive cytochrome P450 (CYP)-mediated metabolic activation of the compound to reactive intermediates. The aim of the present study was to examine the early, cell-specific changes leading to cell death in the olfactory mucosa of mice exposed to 2,6-diClPh-MeSO(2). We have examined the expression of the ER-specific stress protein GRP78, the presence of secretory glycoproteins, and the cellular activation of the initiator caspase 12 and the downstream effector caspase 3. 2,6-DiClPh-MeSO(2) induced rapid and cell-specific expression of GRP78, and activation of caspases 12 and 3 in the Bowman's glands. No similar early onset changes in the neuroepithelium were observed. Based on these results, we propose that extensive lesions are initiated in the Bowman's glands and that the metabolic activation of 2,6-diClPh-MeSO(2) elicits ER-stress response and subsequent apoptotic signaling at this site. Since most of the Bowman's glands had oncotic morphology, the results suggest that the terminal phase of apoptosis was blocked and that these glands finally succumb to other routes of cell death.
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| 30. |
- Garcia, Juliana, et al.
(författare)
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A breakthrough on Amanita phalloides poisoning : an effective antidotal effect by polymyxin B
- 2015
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Ingår i: Archives of Toxicology. - : Springer Science and Business Media LLC. - 0340-5761 .- 1432-0738. ; 89:12, s. 2305-2323
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Tidskriftsartikel (refereegranskat)abstract
- Amanita phalloides is responsible for more than 90 % of mushroom-related fatalities, and no effective antidote is available. alpha-Amanitin, the main toxin of A. phalloides, inhibits RNA polymerase II (RNAP II), causing hepatic and kidney failure. In silico studies included docking and molecular dynamics simulation coupled to molecular mechanics with generalized Born and surface area method energy decomposition on RNAP II. They were performed with a clinical drug that shares chemical similarities to alpha-amanitin, polymyxin B. The results show that polymyxin B potentially binds to RNAP II in the same interface of alpha-amanitin, preventing the toxin from binding to RNAP II. In vivo, the inhibition of the mRNA transcripts elicited by alpha-amanitin was efficiently reverted by polymyxin B in the kidneys. Moreover, polymyxin B significantly decreased the hepatic and renal alpha-amanitin-induced injury as seen by the histology and hepatic aminotransferases plasma data. In the survival assay, all animals exposed to alpha-amanitin died within 5 days, whereas 50 % survived up to 30 days when polymyxin B was administered 4, 8, and 12 h post-alpha-amanitin. Moreover, a single dose of polymyxin B administered concomitantly with alpha-amanitin was able to guarantee 100 % survival. Polymyxin B protects RNAP II from inactivation leading to an effective prevention of organ damage and increasing survival in alpha-amanitin-treated animals. The present use of clinically relevant concentrations of an already human-use-approved drug prompts the use of polymyxin B as an antidote for A. phalloides poisoning in humans.
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| 31. |
- Gassmann, Kathrin, et al.
(författare)
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BDE-47 and 6-OH-BDE-47 modulate calcium homeostasis in primary fetal human neural progenitor cells via ryanodine receptor-independent mechanisms
- 2014
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Ingår i: Archives of Toxicology. - : Springer Science and Business Media LLC. - 0340-5761 .- 1432-0738. ; 88:8, s. 1537-1548
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Tidskriftsartikel (refereegranskat)abstract
- Polybrominated diphenyl ethers (PBDEs) are bioaccumulating flame retardants found in rising concentrations in human tissue. Epidemiological and animal studies have raised concern for their potential to induce developmental neurotoxicity (DNT). Considering the essential role of calcium homeostasis in neurodevelopment, PBDE-induced disturbance of intracellular calcium concentration ([Ca2+](i)) may underlie PBDE-induced DNT. To test this hypothesis, we investigated acute effects of BDE-47 and 6-OH-BDE-47 on [Ca2+](i) in human neural progenitor cells (hNPCs) and unraveled involved signaling pathways. Short-time differentiated hNPCs were exposed to BDE-47, 6-OH-BDE-47, and multiple inhibitors/stimulators of presumably involved signaling pathways to determine possible effects on [Ca2+](i) by single-cell microscopy with the fluorescent dye Fura-2. Initial characterization of calcium signaling pathways confirmed the early developmental stage of hNPCs. In these cells, BDE-47 (2 mu M) and 6-OH-BDE-47 (0.2 mu M) induce [Ca2+](i) transients. This increase in [Ca2+](i) is due to extracellular Ca2+ influx and intracellular release of Ca2+, mainly from the endoplasmic reticulum (ER). While extracellular Ca2+ seems to enter the cytoplasm upon 6-OH-BDE-47 by interfering with the cell membrane and independent of Ca2+ ion channels, ER-derived Ca2+ is released following activation of protein lipase C and inositol 1,4,5-trisphosphate receptor, but independently of ryanodine receptors. These findings illustrate that immature developing hNPCs respond to low concentrations of 6-OH-BDE-47 by an increase in [Ca2+](i) and provide new mechanistic explanations for such BDE-induced calcium disruption. Thus, these data support the possibility of a critical window of PBDE exposure, i.e., early human brain development, which has to be acknowledged in risk assessment.
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| 32. |
- Gliga, Anda R., et al.
(författare)
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Mild steel welding is associated with alterations in circulating levels of cancer-related proteins
- 2019
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Ingår i: Archives of Toxicology. - : Springer Science and Business Media LLC. - 0340-5761 .- 1432-0738. ; 93:12, s. 3535-3547
-
Tidskriftsartikel (refereegranskat)abstract
- Welding fumes were recently classified as carcinogenic to humans and worldwide millions work as welders or perform welding operations. The purpose of this study was to identify new biomarkers of welding-induced carcinogenesis. We evaluated a panel of 91 putative cancer-related proteins in serum in a cohort of welders working with mild steel (n = 77) and controls (n = 94) from southern Sweden sampled on two occasions 6-year apart using a longitudinal analysis (linear mixed models). The significant results from the longitudinal analysis were tested for reproducibility in welders (n = 88) and controls (n = 69) sampled once during the same sampling period as timepoint 1 or timepoint 2 (linear regression models), i.e., in a cross-sectional setting. The models were adjusted for age, body-mass index, and use of snus. All study participants were non-smokers at recruitment. Exposure to welding fumes was assessed using questionnaires and respirable dust measurement in the breathing zone that was adjusted for personal respiratory protection equipment. The median respirable dust in welders was 0.7 (0.2–4.2) and 0.5 (0.1–1.9) mg/m3 at the first and second timepoints, respectively. We identified 14 cancer-related proteins that were differentially expressed in welders versus controls in the longitudinal analysis, out of which three were also differentially expressed in the cross-sectional analysis (cross-sectional group). Namely, syndecan 1 (SDC1), folate receptor 1 (FOLR1), and secreted protein acidic and cysteine rich (SPARC) were downregulated, in welders compared with controls. In addition, FOLR1 was negatively associated with years welding. Disease and function analysis indicated that the top proteins are related to lung cancer as well as cell invasion and migration. Our study indicates that moderate exposure to welding fumes is associated with changes in circulating levels of putative cancer-related proteins, out of which FOLR1 showed a clear dose–response relationship. It is, however, unclear to which extent these changes are adaptive or potential early biomarkers of cancer.
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| 33. |
- Gliga, Anda R, et al.
(författare)
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Prenatal arsenic exposure is associated with increased plasma IGFBP3 concentrations in 9-year-old children partly via changes in DNA methylation
- 2018
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Ingår i: Archives of Toxicology. - : Springer Science and Business Media LLC. - 0340-5761 .- 1432-0738. ; 92:8, s. 2487-2500
-
Tidskriftsartikel (refereegranskat)abstract
- Exposure to inorganic arsenic (As), a carcinogen and epigenetic toxicant, has been associated with lower circulating levels of insulin-like growth factor 1 (IGF1) and impaired growth in children of pre-school age. The aim of this study was to assess the potential impact of exposure to As on IGF1 and insulin-like growth factor-binding protein 3 (IGFBP3) as well as DNA methylation changes in 9-year-old children. To this end, we studied 9-year-old children from a longitudinal mother-child cohort in rural Bangladesh (n = 551). Prenatal and concurrent exposure to As was assessed via concentrations in maternal urine at gestational week 8 and in child urine at 9 years, measured by HPLC-HG-ICPMS. Plasma IGF1 and IGFBP3 concentrations were quantified with immunoassays. DNA methylation was measured in blood mononuclear cells at 9 years in a sub-sample (n = 113) using the Infinium HumanMethylation450K BeadChip. In multivariable-adjusted linear regression models, prenatal As (natural log-transformed), but not children's concurrent urinary As, was positively associated with IGFBP3 concentrations (β = 76, 95% CI 19, 133). As concentrations were not associated with IGF1. DNA methylation analysis revealed CpGs associated with both prenatal As and IGFBP3. Mediation analysis suggested that methylation of 12 CpG sites for all children was mediator of effect for the association between prenatal As and IGFBP3. We also found differentially methylated regions, generally hypermethylated, that were associated with both prenatal As and IGFBP3. In all, our study revealed that prenatal exposure to As was positively associated with IGFBP3 concentrations in children at 9 years, independent of IGF1, and this association may, at least in part, be epigenetically mediated.
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| 34. |
- Godoy, Patricio, et al.
(författare)
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Recent advances in 2D and 3D in vitro systems using primary hepatocytes, alternative hepatocyte sources and non-parenchymal liver cells and their use in investigating mechanisms of hepatotoxicity, cell signaling and ADME
- 2013
-
Ingår i: Archives of Toxicology. - : Springer Science and Business Media LLC. - 0340-5761 .- 1432-0738. ; 87:8, s. 1315-1530
-
Forskningsöversikt (refereegranskat)abstract
- This review encompasses the most important advances in liver functions and hepatotoxicity and analyzes which mechanisms can be studied in vitro. In a complex architecture of nested, zonated lobules, the liver consists of approximately 80 % hepatocytes and 20 % non-parenchymal cells, the latter being involved in a secondary phase that may dramatically aggravate the initial damage. Hepatotoxicity, as well as hepatic metabolism, is controlled by a set of nuclear receptors (including PXR, CAR, HNF-4 alpha, FXR, LXR, SHP, VDR and PPAR) and signaling pathways. When isolating liver cells, some pathways are activated, e.g., the RAS/MEK/ERK pathway, whereas others are silenced (e.g. HNF-4 alpha), resulting in up- and downregulation of hundreds of genes. An understanding of these changes is crucial for a correct interpretation of in vitro data. The possibilities and limitations of the most useful liver in vitro systems are summarized, including three-dimensional culture techniques, co-cultures with non-parenchymal cells, hepatospheres, precision cut liver slices and the isolated perfused liver. Also discussed is how closely hepatoma, stem cell and iPS cell-derived hepatocyte-like-cells resemble real hepatocytes. Finally, a summary is given of the state of the art of liver in vitro and mathematical modeling systems that are currently used in the pharmaceutical industry with an emphasis on drug metabolism, prediction of clearance, drug interaction, transporter studies and hepatotoxicity. One key message is that despite our enthusiasm for in vitro systems, we must never lose sight of the in vivo situation. Although hepatocytes have been isolated for decades, the hunt for relevant alternative systems has only just begun.
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| 35. |
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| 36. |
- Grinberg, Marianna, et al.
(författare)
-
Toxicogenomics directory of chemically exposed human hepatocytes
- 2014
-
Ingår i: Archives of Toxicology. - : Springer Science and Business Media LLC. - 1432-0738 .- 0340-5761. ; 88:12, s. 2261-2287
-
Tidskriftsartikel (refereegranskat)abstract
- A long-term goal of numerous research projects is to identify biomarkers for in vitro systems predicting toxicity in vivo. Often, transcriptomics data are used to identify candidates for further evaluation. However, a systematic directory summarizing key features of chemically influenced genes in human hepatocytes is not yet available. To bridge this gap, we used the Open TG-GATES database with Affymetrix files of cultivated human hepatocytes incubated with chemicals, further sets of gene array data with hepatocytes from human donors generated in this study, and publicly available genome-wide datasets of human liver tissue from patients with non-alcoholic steatohepatitis (NASH), cirrhosis, and hepatocellular cancer (HCC). After a curation procedure, expression data of 143 chemicals were included into a comprehensive biostatistical analysis. The results are summarized in the publicly available toxicotranscriptomics directory (http://wiki.toxbank.net/toxicogenomics-map/) which provides information for all genes whether they are up- or downregulated by chemicals and, if yes, by which compounds. The directory also informs about the following key features of chemically influenced genes: (1) Stereotypical stress response. When chemicals induce strong expression alterations, this usually includes a complex but highly reproducible pattern named 'stereotypical response.' On the other hand, more specific expression responses exist that are induced only by individual compounds or small numbers of compounds. The directory differentiates if the gene is part of the stereotypical stress response or if it represents a more specific reaction. (2) Liver disease-associated genes. Approximately 20 % of the genes influenced by chemicals are up- or downregulated, also in liver disease. Liver disease genes deregulated in cirrhosis, HCC, and NASH that overlap with genes of the aforementioned stereotypical chemical stress response include CYP3A7, normally expressed in fetal liver; the phase II metabolizing enzyme SULT1C2; ALDH8A1, known to generate the ligand of RXR, one of the master regulators of gene expression in the liver; and several genes involved in normal liver functions: CPS1, PCK1, SLC2A2, CYP8B1, CYP4A11, ABCA8, and ADH4. (3) Unstable baseline genes. The process of isolating and the cultivation of hepatocytes was sufficient to induce some stress leading to alterations in the expression of genes, the so-called unstable baseline genes. (4) Biological function. Although more than 2,000 genes are transcriptionally influenced by chemicals, they can be assigned to a relatively small group of biological functions, including energy and lipid metabolism, inflammation and immune response, protein modification, endogenous and xenobiotic metabolism, cytoskeletal organization, stress response, and DNA repair. In conclusion, the introduced toxicotranscriptomics directory offers a basis for a rationale choice of candidate genes for biomarker evaluation studies and represents an easy to use source of background information on chemically influenced genes.
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| 37. |
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| 38. |
- Gustafsson, Sofia, 1982-, et al.
(författare)
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Effects of cannabinoids and related fatty acids upon the viability of P19 embryonal carcinoma cells
- 2013
-
Ingår i: Archives of Toxicology. - : Springer Berlin/Heidelberg. - 0340-5761 .- 1432-0738. ; 87:11, s. 1939-1951
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Tidskriftsartikel (refereegranskat)abstract
- Compounds acting on the cannabinoid (CB) receptors are involved in the control of cell fate, and there is an emerging consensus that CBs have anticancer effects. However, the CB-mediated effects are contradictory since some studies suggest stimulatory effects on cancer cell proliferation, and CBs have been shown to stimulate both proliferation and differentiation of other mitotic cells such as stem and progenitor cells. In this study, the concentration-dependent effects of synthetic and endogenous CBs on the viability of mouse P19 embryonal carcinoma (EC) cells have been examined by using fluorescence assays of cell membrane integrity, cell proliferation, oxidative stress, and detection of apoptosis and necrosis. All compounds examined produced a concentration-dependent decrease in cell viability in the micromolar range, with the potent CB receptor agonist HU 210 and the enantiomer HU 211(with no CB receptor activity) being the most potent compounds examined with apparent IC50 values of 1 µM and 0.6 µM, respectively. The endogenous CB anandamide showed similar potency and efficacy as structurally related polyunsaturated fatty acids with no reported activity at the CB receptors. The rapid (within hours) decrease in cell viability induced by the examined CBs suggests cytocidal rather than antiproliferative effects, and is dependent on the plating cell population density with the highest toxicity around 100 cells/mm2. The CB-induced cytotoxicity, that appears to involve CB receptors and the sphingomyelin-ceramide pathway, is a mixture of both apoptosis and necrosis that can be blocked by the antioxidants α-tocopherol and N-acetylcysteine. In conclusion, both synthetic and endogenous CBs, produce seemingly unspecific cytotoxic effects in the P19 EC cells.
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| 39. |
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| 40. |
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| 41. |
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| 42. |
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| 43. |
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| 44. |
- Hendriks, Hester S., et al.
(författare)
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Effects on neonatal exposure to the flame retardant tetrabrombisphenol-A, aluminum diethylphosphinate or zinc stannate on long-term, potentiation and synaptic protein levels in mice
- 2015
-
Ingår i: Archives of Toxicology. - : Springer Nature. - 0340-5761 .- 1432-0738. ; 89:12, s. 2345-2354
-
Tidskriftsartikel (refereegranskat)abstract
- Brominated flame retardants such as tetrabromobisphenol-A (TBBPA) may exert (developmental) neurotoxic effects. However, data on (neuro)toxicity of halogen-free flame retardants (HFFRs) are scarce. Recent in vitro studies indicated a high neurotoxic potential for some HFFRs, e.g., zinc stannate (ZS), whereas the neurotoxic potential of other HFFRs, such as aluminum diethylphosphinate (Alpi), appears low. However, the in vivo (neuro)toxicity of these compounds is largely unknown. We therefore investigated effects of neonatal exposure to TBBPA, Alpi or ZS on synaptic plasticity in mouse hippocampus. Male C57bl/6 mice received a single oral dose of 211 µmol/kg bw TBBPA, Alpi or ZS on postnatal day (PND) 10. On PND 17–19, effects on hippocampal synaptic plasticity were investigated using ex vivo extracellular field recordings. Additionally, we measured levels of postsynaptic proteins involved in long-term potentiation (LTP) as well as flame retardant concentrations in brain, muscle and liver tissues. All three flame retardants induced minor, but insignificant, effects on LTP. Additionally, TBBPA induced a minor decrease in post-tetanic potentiation. Despite these minor effects, expression of selected synaptic proteins involved in LTP was not affected. The flame retardants could not be measured in significant amounts in the brains, suggesting low bioavailability and/or rapid elimination/metabolism. We therefore conclude that a single neonatal exposure on PND 10 to TBBPA, Alpi or ZS does affect neurodevelopment and synaptic plasticity only to a small extent in mice. Additional data, in particular on persistence, bioaccumulation and (in vivo) toxicity, following prolonged (developmental) exposure are required for further (human) risk assessment.
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| 45. |
- Hermansson, Veronica, et al.
(författare)
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Comparative CYP-dependent binding of the adrenocortical toxicants 3-methylsulfonyl-DDE and o,p′-DDD in Y-1 adrenal cells
- 2007
-
Ingår i: Archives of Toxicology. - : Springer Science and Business Media LLC. - 0340-5761 .- 1432-0738. ; 81:11, s. 793-801
-
Tidskriftsartikel (refereegranskat)abstract
- The environmental pollutant 3-MeSO2–DDE [2-(3-methylsulfonyl-4-chlorophenyl)-2-(4-chlorophenyl)-1,1-dichloroethene] is an adrenocortical toxicant in mice, specifically in the glucocorticoid-producing zona fasciculata, due to a cytochrome P450 11B1 (CYP11B1)-catalysed bioactivation and formation of covalently bound protein adducts. o,p′-DDD [2-(2-chlorophenyl)-2-(4-chlorophenyl)-1,1-dichloroethane] is toxic and inhibits steroidogenesis in the human adrenal cortex after bioactivation by unidentified CYPs, but does not exert any toxic effects on the mouse adrenal. As a step towards determining in vitro/in vivo relationships for the CYP-catalysed binding and toxicity of 3-MeSO2–DDE and o,p′-DDD, we have investigated the irreversible protein binding of these two toxicants in the murine adrenocortical cell line Y-1. The irreversible binding of 3-MeSO2–DDE previously demonstrated in vivo was successfully reproduced and could be inhibited by the CYP-inhibitors etomidate, ketoconazole and metyrapone. Surprisingly, o,p′-DDD reached similar levels of binding as 3-MeSO2–DDE. The binding of o,p′-DDD was sensitive to etomidate and ketoconazole, but not to metyrapone. Moreover, GSH depletion increased the binding of 3-MeSO2–DDE, but not of o,p′-DDD, indicating an important role of GSH conjugation in the detoxification of the 3-MeSO2–DDE-derived reactive metabolite. In addition, the specificity of CYP11B1 in activating 3-MeSO2–DDE was investigated using structurally analogous compounds. None of the analogues produced histopathological lesions in the mouse adrenal in vivo following a single i.p. injection of 100 mg/kg body weight, but two of the compounds were able to decrease the irreversible binding of 3-MeSO2–DDE to Y-1 cells. These results indicate that the bioactivation of 3-MeSO2–DDE by CYP11B1 is highly structure-dependent. In conclusion, both 3-MeSO2–DDE and o,p′-DDD bind irreversibly to Y-1 cells despite differences in binding and adrenotoxicity in mice in vivo. This reveals a notable in vitro/in vivo discrepancy, the contributing factors of which remain unexplained. We consider the Y-1 cell line as appropriate for studies of the cellular mechanisms behind the adrenocortical toxicity of these substances.
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| 46. |
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| 47. |
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| 48. |
- Johansson, HKL, et al.
(författare)
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Putative adverse outcome pathways for female reproductive disorders to improve testing and regulation of chemicals
- 2020
-
Ingår i: Archives of toxicology. - : Springer Science and Business Media LLC. - 1432-0738 .- 0340-5761. ; 94:10, s. 3359-3379
-
Tidskriftsartikel (refereegranskat)abstract
- Modern living challenges female reproductive health. We are witnessing a rise in reproductive disorders and drop in birth rates across the world. The reasons for these manifestations are multifaceted and most likely include continuous exposure to an ever-increasing number of chemicals. The cause–effect relationships between chemical exposure and female reproductive disorders, however, have proven problematic to determine. This has made it difficult to assess the risks chemical exposures pose to a woman’s reproductive development and function. To address this challenge, this review uses the adverse outcome pathway (AOP) concept to summarize current knowledge about how chemical exposure can affect female reproductive health. We have a special focus on effects on the ovaries, since they are essential for lifelong reproductive health in women, being the source of both oocytes and several reproductive hormones, including sex steroids. The AOP framework is widely accepted as a new tool for toxicological safety assessment that enables better use of mechanistic knowledge for regulatory purposes. AOPs equip assessors and regulators with a pragmatic network of linear cause–effect relationships, enabling the use of a wider range of test method data in chemical risk assessment and regulation. Based on current knowledge, we propose ten putative AOPs relevant for female reproductive disorders that can be further elaborated and potentially be included in the AOPwiki. This effort is an important step towards better safeguarding the reproductive health of all girls and women.
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| 49. |
- Jonsson, Kent-Olov, et al.
(författare)
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AM404 and VDM 11 non-specifically inhibit C6 glioma cell proliferation at concentrations used to block the cellular accumulation of the endocannabinoid anandamide.
- 2003
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Ingår i: Archives of Toxicology. - : Springer Science and Business Media LLC. - 0340-5761 .- 1432-0738. ; 77:4, s. 201-207
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Tidskriftsartikel (refereegranskat)abstract
- AM404 [ N-(4-hydroxyphenyl)arachidonylamide] and VDM 11 [(5 Z,8 Z,11 Z,14 Z)- N-(4-hydroxy-2-methylphenyl)-5,8,11,14-eicosatetraenamide] are commonly used to prevent the cellular accumulation of the endocannabinoid anandamide, and thereby to potentiate its actions. However, it has been reported that AM404 can produce an influx of calcium into cells, which might be expected to have deleterious effects on cell proliferation. In the present study, AM404 and VDM 11 were found to reduce C6 glioma cell proliferation with IC(50) values of 4.9 and 2.7 microM, respectively. The inhibition of cell proliferation following a 96-h exposure was not accompanied by dramatic caspase activation, and was not prevented by either a combination of cannabinoid and vanilloid receptor antagonists, or by the antioxidant alpha-tocopherol, suggestive of a non-specific mode of action. Similar results were seen with palmitoylisopropylamide, although this compound only produced significant inhibition of cell proliferation at 30 microM concentrations. AM404 (1 microM), VDM 11 (1 microM) and palmitoylisopropylamide (3-30 microM), i.e. concentrations producing relatively modest effects on cell proliferation per se, reduced the vanilloid receptor-mediated antiproliferative effects of anandamide, as would be expected for compounds preventing the cellular accumulation of anandamide (and thereby access to its binding site on the vanilloid receptor). It is concluded that concentrations of AM404 and VDM 11 that are generally used to reduce the cellular accumulation of anandamide have deleterious effects upon cell proliferation, and that lower concentrations of these compounds may be more appropriate to use in vitro.
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| 50. |
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