| 1. |
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| 2. |
- Ali, Imran, et al.
(författare)
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From pure compounds to complex exposure : Effects of dietary cadmium and lignans on estrogen, epidermal growth factor receptor, and mitogen activated protein kinase signaling in vivo.
- 2016
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Ingår i: Toxicology Letters. - : Elsevier BV. - 0378-4274 .- 1879-3169. ; 253
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Tidskriftsartikel (refereegranskat)abstract
- Exposure to environmental endocrine active compounds correlates with altered susceptibility to disease in human populations. Chemical risk assessment is single compound based, although exposure often takes place as heterogeneous mixtures of man-made and natural substances within complex matrices like diet. Here we studied whether the effects of cadmium and enterolactone on endocrine endpoints in dietary exposure can be predicted based on pure compound effects. Ovariectomized estrogen reporter ERE-luciferase (ERE-luc) mice were maintained on diets that intrinsically contain increasing concentrations of cadmium and enterolactone precursors for three and 21 days. The activation of the ERE-luc, epidermal growth factor receptor (EGFR), mitogen activated protein kinase (MAPK)-ERK1/2, and classical estrogen responses were measured. Interactions between the diets and endogenous hormone were evaluated by challenging the animals with 17β-estradiol. Compared to animals on basal purified diet, mice consuming experimental diets were exposed to significantly higher levels of cadmium and enterolactone, yet the exposure remained comparable to typical human dietary intake. Surprisingly, we could not detect effects on endpoints regulated by pure enterolactone, such as ERE-luc activation. However, cadmium accumulation in the liver was accompanied with activation of EGFR and MAPK-ERK1/2 in line with our earlier CdCl2 studies. Further, attenuation of 17β-estradiol-induced ERE-luc response in liver by experimental diets was observed. Our findings indicate that the exposure context can have substantial effects on the activity of endocrine active compounds in vivo. Thus, whenever possible, a context that mimics human exposure should be tested along with pure compounds.
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| 3. |
- Barde, Swapnali, et al.
(författare)
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Alterations in the neuropeptide galanin system in major depressive disorder involve levels of transcripts, methylation, and peptide
- 2016
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Ingår i: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA. - : NATL ACAD SCIENCES. - 0027-8424 .- 1091-6490. ; 113:52, s. E8472-E8481
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Tidskriftsartikel (refereegranskat)abstract
- Major depressive disorder (MDD) is a substantial burden to patients, families, and society, but many patients cannot be treated adequately. Rodent experiments suggest that the neuropeptide galanin (GAL) and its three G protein-coupled receptors, GAL(1-3), are involved in mood regulation. To explore the translational potential of these results, we assessed the transcript levels (by quantitative PCR), DNA methylation status (by bisulfite pyrosequencing), and GAL peptide by RIA of the GAL system in postmortem brains from depressed persons who had committed suicide and controls. Transcripts for all four members were detected and showed marked regional variations, GAL and galanin receptor 1 (GALR1) being most abundant. Striking increases in GAL and GALR3 mRNA levels, especially in the noradrenergic locus coeruleus and the dorsal raphe nucleus, in parallel with decreased DNA methylation, were found in both male and female suicide subjects as compared with controls. In contrast, GAL and GALR3 transcript levels were decreased, GALR1 was increased, and DNA methylation was increased in the dorsolateral prefrontal cortex of male suicide subjects, however, there were no changes in the anterior cingulate cortex. Thus, GAL and its receptor GALR3 are differentially methylated and expressed in brains of MDD subjects in a region- and sex-specific manner. Such an epigenetic modification in GALR3, a hyperpolarizing receptor, might contribute to the dysregulation of noradrenergic and serotonergic neurons implicated in the pathogenesis of MDD. Thus, one may speculate that a GAL(3) antagonist could have antidepressant properties by disinhibiting the firing of these neurons, resulting in increased release of noradrenaline and serotonin in forebrain areas involved in mood regulation.
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| 4. |
- Blanc, Mélanie, 1993-, et al.
(författare)
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Environmental chemicals differentially affect epigenetic-related mechanisms in the zebrafish liver (ZF-L) cell line and in zebrafish embryos
- 2019
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Ingår i: Aquatic Toxicology. - : Elsevier. - 0166-445X .- 1879-1514. ; 215
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Tidskriftsartikel (refereegranskat)abstract
- A number of chemicals have been shown to affect epigenetic patterning and functions. Since epigenetic mechanisms regulate transcriptional networks, epigenetic changes induced by chemical exposure can represent early molecular events for long-term adverse physiological effects. Epigenetics has thus appeared as a research field of major interest within (eco)toxicological sciences. The present study aimed at measuring effects on epigenetic-related mechanisms of selected environmental chemicals (bisphenols, perfluorinated chemicals, methoxychlor, permethrin, vinclozolin and coumarin 47) in zebrafish embryos and liver cells (ZFL). Transcription of genes related to DNA methylation and histone modifications was measured and global DNA methylation was assessed in ZFL cells using the LUMA assay. The differences in results gathered from both models suggest that chemicals affect different mechanisms related to epigenetics in embryos and cells. In zebrafish embryos, exposure to bisphenol A, coumarin 47, methoxychlor and permethrin lead to significant transcriptional changes in epigenetic factors suggesting that they can impact early epigenome reprogramming related to embryonic development. In ZFL cells, significant transcriptional changes were observed upon exposure to all chemicals but coumarin 47; however, only perfluorooctane sulfonate induced significant effects on global DNA methylation. Notably, in contrast to the other tested chemicals, perfluorooctane sulfonate affected only the expression of the histone demethylase kdm5ba. In addition, kdm5ba appeared as a sensitive gene in zebrafish embryos as well. Taken together, the present results suggest a role for kdm5ba in regulating epigenetic patterns in response to chemical exposure, even though mechanisms remain unclear. To confirm these findings, further evidence is required regarding changes in site-specific histone marks and DNA methylation together with their long-term effects on physiological outcomes.
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| 5. |
- Blanc, Mélanie, 1993-
(författare)
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How can an organism´s life experience affect their descendants? Insights from epigenetic and transgenerational effects of chemical exposure in zebrafish
- 2020
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Environmental pollution causes approx. 10% of human diseases, and some develop in the progeny because of parental exposure. Effects passed on to subsequent generations may be a consequence of genetic mutations, or of inherited changes in epigenetic patterns. Epigenetics is the study of mitotically or meiotically heritable changes in gene function that cannot be explained by changes in the DNA sequence. Several chemicals have been suggested to induce epigenetic dysregulation leading to multigenerational and transgenerational effects, i.e. effects that can be observed in completely unexposed generations. However, mechanisms underlying the inheritance of epigenetic changes and their implication in phenotypic adversities are complex and not well-understood. The overall aim of this thesis was to study adverse effects and underlying molecular changes in several generations of zebrafish after parental exposure to selected industrial chemicals. To this end, molecular (lipidomic, transcriptomic, epigenomic) and behavioral analyses were performed. Zebrafish is an acknowledged model for vertebrates in toxicology and biomedicine; as such, the findings can be relevant to many organisms including human. The results from this thesis showed that different types of chemicals, polychlorinated biphenyls, polybromodiphenyl ethers, and permethrin, induced transgenerational effects in concentrations relevant to environmental or human exposures. Impact on anxiety and locomotor activity of zebrafish was observed over several generations. Gene expression and epigenetic (DNA methylation) alterations were partly inherited and suggest stable alteration of specific functions such as glutamatergic/GABAergic neurotransmission and synaptic plasticity. Finally, the findings shed light on experimental limitations and research perspectives, which we expect will contribute to the design of future studies on epigenetically inherited effects of any environmental stress.
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| 6. |
- Blanc, Mélanie, 1993-, et al.
(författare)
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The insecticide permethrin induces transgenerational behavioral changes linked to transcriptomic and epigenetic alterations in zebrafish (Danio rerio)
- 2021
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Ingår i: Science of the Total Environment. - : Elsevier. - 0048-9697 .- 1879-1026. ; 779
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Tidskriftsartikel (refereegranskat)abstract
- The pyrethroid insecticide permethrin is widely used for agricultural and domestic purposes. Previous data indicated that it acts as a developmental neurotoxicant and can induce transgenerational effects in non-target organisms. However, associated underlying mechanisms remain unclear. The aim of this study was to investigate permethrin-related transgenerational effects in the zebrafish model, and to identify possible molecular mechanisms underlying inheritance. Zebrafish (F0) were exposed to permethrin during early-life (2 h post-fertilization up to 28 days). The F1 and F2 offspring generations were obtained by pairing exposed F0 males and females, and were bred unexposed. Locomotor and anxiety behavior were investigated, together with transcriptomic and epigenomic (DNA methylation) changes in brains. Permethrin exposed F0 fish were hypoactive at adulthood, while males from the F1 and F2 generations showed a specific decrease in anxiety-like behavior. In F0, transcriptomic data showed enrichment in pathways related to glutamatergic synapse activity, which may partly underlie the behavioral effects. In F1 and F2 males, dysregulation of similar pathways was observed, including a subset of differentially methylated regions that were inherited from the F0 to the F2 generation and indicated stable dysregulation of glutamatergic signaling. Altogether, the present results provide novel evidence on the transgenerational neurotoxic effects of permethrin, as well as mechanistic insight: a transient exposure induces persistent transcriptional and DNA methylation changes that may translate into transgenerational alteration of glutamatergic signaling and, thus, into behavioral alterations.
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| 7. |
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| 8. |
- Bopp, Stephanie K., et al.
(författare)
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Current EU research activities on combined exposure to multiple chemicals
- 2018
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Ingår i: Environment International. - : Elsevier. - 0160-4120 .- 1873-6750. ; 120, s. 544-562
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Forskningsöversikt (refereegranskat)abstract
- Humans and wildlife are exposed to an intractably large number of different combinations of chemicals via food, water, air, consumer products, and other media and sources. This raises concerns about their impact on public and environmental health. The risk assessment of chemicals for regulatory purposes mainly relies on the assessment of individual chemicals. If exposure to multiple chemicals is considered in a legislative framework, it is usually limited to chemicals falling within this framework and co-exposure to chemicals that are covered by a different regulatory framework is often neglected. Methodologies and guidance for assessing risks from combined exposure to multiple chemicals have been developed for different regulatory sectors, however, a harmonised, consistent approach for performing mixture risk assessments and management across different regulatory sectors is lacking. At the time of this publication, several EU research projects are running, funded by the current European Research and Innovation Programme Horizon 2020 or the Seventh Framework Programme. They aim at addressing knowledge gaps and developing methodologies to better assess chemical mixtures, by generating and making available internal and external exposure data, developing models for exposure assessment, developing tools for in silico and in vitro effect assessment to be applied in a tiered framework and for grouping of chemicals, as well as developing joint epidemiological-toxicological approaches for mixture risk assessment and for prioritising mixtures of concern. The projects EDC-MixRisk, EuroMix, EUToxRisk, HBM4EU and SOLUTIONS have started an exchange between the consortia, European Commission Services and EU Agencies, in order to identify where new methodologies have become available and where remaining gaps need to be further addressed. This paper maps how the different projects contribute to the data needs and assessment methodologies and identifies remaining challenges to be further addressed for the assessment of chemical mixtures.
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| 9. |
- Bornehag, Carl-Gustaf, 1957-, et al.
(författare)
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A Novel Approach to Chemical Mixture Risk Assessment—Linking Data from Population-Based Epidemiology and Experimental Animal Tests
- 2019
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Ingår i: Risk Analysis. - : John Wiley & Sons. - 0272-4332 .- 1539-6924. ; 39:10, s. 2259-2271
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Tidskriftsartikel (refereegranskat)abstract
- Humans are continuously exposed to chemicals with suspected or proven endocrine disrupting chemicals (EDCs). Risk management of EDCs presents a major unmet challenge because the available data for adverse health effects are generated by examining one compound at a time, whereas real-life exposures are to mixtures of chemicals. In this work, we integrate epidemiological and experimental evidence toward a whole mixture strategy for risk assessment. To illustrate, we conduct the following four steps in a case study: (1) identification of single EDCs (“bad actors”)—measured in prenatal blood/urine in the SELMA study—that are associated with a shorter anogenital distance (AGD) in baby boys; (2) definition and construction of a “typical” mixture consisting of the “bad actors” identified in Step 1; (3) experimentally testing this mixture in an in vivo animal model to estimate a dose–response relationship and determine a point of departure (i.e., reference dose [RfD]) associated with an adverse health outcome; and (4) use a statistical measure of “sufficient similarity” to compare the experimental RfD (from Step 3) to the exposure measured in the human population and generate a “similar mixture risk indicator” (SMRI). The objective of this exercise is to generate a proof of concept for the systematic integration of epidemiological and experimental evidence with mixture risk assessment strategies. Using a whole mixture approach, we could find a higher rate of pregnant women under risk (13%) when comparing with the data from more traditional models of additivity (3%), or a compound-by-compound strategy (1.6%).
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| 10. |
- Bornehag, Carl-Gustav, 1957-, et al.
(författare)
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Prenatal exposure to bisphenols and cognitive function in children at 7 years of age in the Swedish SELMA study
- 2021
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Ingår i: Environment International. - : Elsevier. - 0160-4120 .- 1873-6750. ; 150
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Tidskriftsartikel (refereegranskat)abstract
- Background: Experimental evidence demonstrates that exposure to bisphenol A (BPA), and the recently intro-duced alternatives bisphenol S (BPS) and bisphenol F (BPF) alter normal neurodevelopment. More research is needed to evaluate the associations between exposure to individual BPA alternatives and neurodevelopmental outcomes in humans. Objective: The present study aimed at examining the individual associations between prenatal BPA , BPS and BPF exposure and cognitive outcomes in children at age 7 years. Method: Women were enrolled in the Swedish Environmental Longitudinal Mother and Child, Asthma and Al-lergy (SELMA) study, at gestational median week 10.0, and their children were examined for cognitive function at 7 years of age (N = 803). Maternal urina r y BPA , BPS, and BPF concentrations were measured at enrollment and children?s cognitive function at the age of 7 years was measured using the Wechsler Intelligence Scale for Children IV (WISC-IV). Results: A l l three bisphenols were detected in over 90% of the women, where BPA had the highest geometric mean concentrations (1.55 ng/mL), followed by BPF (0.16 ng/mL) and BPS (0.07 ng/mL). Prenatal BPF exposure was associated with decreased f u l l scale IQ (13 =-1.96, 95%CI;-3.12;-0.80), as we l l as with a decrease in a l l four sub scales covering verbal comprehension, perceptual reasoning, working memor y and processing speed. This association corresponded to a 1.6-point lower IQ score for an inter-quartile-range (IQR) change in prenatal BPF exposure (IQR = 0.054 & ndash;0.350 ng/mL). In sex-stratified analyses, significant associations with f u l l scale IQ were found for boys (13 = - 2.86, 95%CI;-4.54;-1.18), while the associations for girls did not reach significance (13 =-1.38, 95%CI;-2.97; 0.22). No significant associations between BPA nor BPS and cognition were found. Discussion: Prenatal exposure to BPF was significantly associated with children?s cognitive function at 7 years. Since BPF is replacing BPA in numerous consumer products globally, this finding urgently ca l l for further studies.
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| 11. |
- Caporale, N., et al.
(författare)
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From cohorts to molecules: Adverse impacts of endocrine disrupting mixtures
- 2022
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 375:6582
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Tidskriftsartikel (refereegranskat)abstract
- Convergent evidence associates exposure to endocrine disrupting chemicals (EDCs) with major human diseases, even at regulation-compliant concentrations. This might be because humans are exposed to EDC mixtures, whereas chemical regulation is based on a risk assessment of individual compounds. Here, we developed a mixture-centered risk assessment strategy that integrates epidemiological and experimental evidence. We identified that exposure to an EDC mixture in early pregnancy is associated with language delay in offspring. At human-relevant concentrations, this mixture disrupted hormone-regulated and disease-relevant regulatory networks in human brain organoids and in the model organisms Xenopus leavis and Danio rerio, as well as behavioral responses. Reinterrogating epidemiological data, we found that up to 54% of the children had prenatal exposures above experimentally derived levels of concern, reaching, for the upper decile compared with the lowest decile of exposure, a 3.3 times higher risk of language delay. © 2022 American Association for the Advancement of Science. All rights reserved.
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| 12. |
- Cediel Ulloa, Andrea, et al.
(författare)
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Epigenetics of methylmercury
- 2023
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Ingår i: Neurotoxicology. - : Elsevier BV. - 0161-813X .- 1872-9711. ; 97, s. 34-46
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Tidskriftsartikel (refereegranskat)abstract
- Purpose of review: Methylmercury (MeHg) is neurotoxic at high levels and particularly affects the developing brain. One proposed mechanism of MeHg neurotoxicity is alteration of the epigenetic programming. In this review, we summarise the experimental and epidemiological literature on MeHg-associated epigenetic changes.Recent findings: Experimental and epidemiological studies have identified changes in DNA methylation following in utero exposure to MeHg, and some of the changes appear to be persistent. A few studies have evaluated associations between MeHg-related changes in DNA methylation and neurodevelopmental outcomes. Experimental studies reveal changes in histone modifications after MeHg exposure, but we lack epidemiological studies supporting such changes in humans. Experimental and epidemiological studies have identified microRNA-related changes associated with MeHg; however, more research is needed to conclude if these changes lead to persistent and toxic effects.Summary: MeHg appears to interfere with epigenetic processes, potentially leading to persistent changes. However, observed associations of mercury with epigenetic changes are as of yet of unknown relevance to neurodevelopmental outcomes.
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| 13. |
- Cediel Ulloa, Andrea, et al.
(författare)
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Impact of endocrine disrupting chemicals on neurodevelopment : the need for better testing strategies for endocrine disruption-induced developmental neurotoxicity
- 2022
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Ingår i: Expert Review of Endocrinology & Metabolism. - : Taylor & Francis. - 1744-6651 .- 1744-8417. ; 17:2, s. 131-141
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Brain development is highly dependent on hormonal regulation. Exposure to chemicals disrupting endocrine signaling has been associated with neurodevelopmental impairment. This raises concern about exposure to the suspected thousands of endocrine disruptors, and has resulted in efforts to improve regulation of these chemicals. Yet, the causal links between endocrine disruption and developmental neurotoxicity, which would be required for regulatory action, are still largely missing. Areas covered: In this review, we illustrate the importance of two endocrine systems, thyroid hormone and retinoic acid pathways, for neurodevelopment. We place special emphasis on TH and RA synthesis, metabolism, and how endocrine disrupting chemicals known or suspected to affect these systems are associated with developmental neurotoxicity. Expert opinion: While it is clear that neurodevelopment is dependent on proper hormonal functioning, and evidence is increasing for developmental neurotoxicity induced by endocrine disrupting chemicals, this is not grasped by current chemical testing. Thus, there is an urgent need to develop test methods detecting endocrine disruption in the context of neurodevelopment. Key to this development is further mechanistic insights on the involvement of endocrine signaling in neurodevelopment as well as increased support to develop and validate new test methods for the regulatory context.
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| 14. |
- Cediel Ulloa, Andrea, et al.
(författare)
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Methylmercury-induced DNA methylation—From epidemiological observations to experimental evidence
- 2022
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Ingår i: Frontiers in Genetics. - : Frontiers Media SA. - 1664-8021. ; 13
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Tidskriftsartikel (refereegranskat)abstract
- Methylmercury (MeHg) is a developmental neurotoxicant, and one potential mechanism of MeHg toxicity is epigenetic dysregulation. In a recent meta-analysis of epigenome-wide association studies (EWAS), associations between prenatal MeHg exposure and DNA methylation at several genomic sites were identified in blood from newborns and children. While EWASs reveal human-relevant associations, experimental studies are required to validate the relationship between exposure and DNA methylation changes, and to assess if such changes have implications for gene expression. Herein, we studied DNA methylation and gene expression of five of the top genes identified in the EWAS meta-analysis, MED31, MRPL19, GGH, GRK1, and LYSMD3, upon MeHg exposure in human SH-SY5Y cells exposed to 8 or 40 nM of MeHg during differentiation, using bisulfite-pyrosequencing and qPCR, respectively. The concentrations were selected to cover the range of MeHg concentrations in cord blood (2–8.5 μg/L) observed in the cohorts included in the EWAS. Exposure to MeHg increased DNA methylation at MED31, a transcriptional regulator essential for fetal development. The results were in concordance with the epidemiological findings where more MED31 methylation was associated with higher concentrations of MeHg. Additionally, we found a non-significant decrease in DNA methylation at GGH, which corresponds to the direction of change observed in the EWAS, and a significant correlation of GGH methylation with its expression. In conclusion, this study corroborates some of the EWAS findings and puts forward candidate genes involved in MeHg’s effects on the developing brain, thus highlighting the value of experimental validation of epidemiological association studies.
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| 15. |
- Cediel-Ulloa, Andrea, 1989-
(författare)
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Novel Endpoints To Unravel Developmental Neurotoxicity : From DNA methylation responses to methylmercury to the in vitro identification of endocrine disruptors
- 2024
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The developing brain is especially sensitive to environmental stressors due to its dependence on the precise spatiotemporal regulation of multiple signals, and the long time period required for its formation. Some chemicals can interfere with molecular and cellular processes driving brain development, including epigenetic processes such as DNA methylation. Hence, identification of DNA methylation changes induced by chemical exposure may serve as early molecular markers for developmental neurotoxicity (DNT). Chemicals known as endocrine disruptors (EDCs) can produce adverse effects due to their capability to alter the endocrine system. Since brain development is highly dependent on endocrine signals, the potential adverse effects of EDCs on brain development needs to be addressed. Detection of DNT in the regulatory context has been based on in vivo testing, however, the financial costs and time intensive characteristics of these methods have resulted in a limited assessment of the DNT hazard of chemicals. In addition, in order to regulate EDCs, it is paramount to demonstrate that their adverse effects are a product of disruption of endocrine signals. Yet, at the moment, there are no approved methods which address both an endocrine mode of action and adverse neurodevelopmental outcomes. This doctoral thesis had two main aims: Firstly, to identify epigenetic changes, at the level of DNA methylation, underlying DNT induced by exposure to methylmercury (MeHg); and secondly, to develop new approach methods (NAMs) for the detection of DNT induced by endocrine disruption. Epigenetic effects were studied both in epidemiological data and experimentally in vitro. Associations between prenatal MeHg exposure and DNA methylation of GRIN2B and NR3C1 were found in children. In vitro validation of DNA methylation changes found in epigenome-wide association studies of populations exposed to MeHg, uncovered the potential involvement of the Mediator Complex Subunit 31 (MED31) in MeHg DNT. To contribute to the endocrine disruption (ED)-induced DNT field, the applicability of an in vitro model composed of murine neural progenitor cells (the C17.2 cell-line) was evaluated. We found that C17.2 neural differentiation and morphology were sensitive to retinoic acid (RAR), retinoic X (RXR), peroxisome proliferator-activated β/δ (PPARβ/δ), and glucocorticoid (GR) agonism. Furthermore, two out of 25 tested EDCs decreased neurite outgrowth and branching in the C17.2 system. These effects were recovered by co-exposure of the chemicals with antagonists of RAR, RXR, or PPARβ/δ, indicating that their DNT effect is mediated by hormonal disruption. Altogether, this thesis contributed to the development of new methodologies and endpoints for the assessment of DNT induced by MeHg and EDCs.
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| 16. |
- Cediel Ulloa, Andrea, et al.
(författare)
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Prenatal methylmercury exposure and DNA methylation in seven-year-old children in the Seychelles Child Development Study
- 2021
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Ingår i: Environment International. - : Elsevier. - 0160-4120 .- 1873-6750. ; 147
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundMethylmercury (MeHg) is present in fish and is a neurotoxicant at sufficiently high levels. One potential mechanism of MeHg toxicity early in life is epigenetic dysregulation that may affect long-term neurodevelopment. Altered DNA methylation of nervous system-related genes has been associated with adult mental health outcomes.ObjectiveTo assess associations between prenatal MeHg exposure and DNA methylation (at the cytosine of CG dinucleotides, CpGs) in three nervous system-related genes, encoding brain-derived neurotropic factor (BDNF), glutamate receptor subunit NR2B (GRIN2B), and the glucocorticoid receptor (NR3C1), in children who were exposed to MeHg in utero.MethodsWe tested 406 seven-year-old Seychellois children participating in the Seychelles Child Development Study (Nutrition Cohort 2), who were prenatally exposed to MeHg from maternal fish consumption. Total mercury in maternal hair (prenatal MeHg exposure measure) collected during pregnancy was measured using atomic absorption spectroscopy. Methylation in DNA from the children’s saliva was measured by pyrosequencing. To assess associations between prenatal MeHg exposure and CpG methylation at seven years of age, we used multivariable linear regression models adjusted for covariates.ResultsWe identified associations with prenatal MeHg exposure for DNA methylation of one GRIN2B CpG and two NR3C1 CpGs out of 12 total CpG sites. Higher prenatal MeHg was associated with higher methylation for each CpG site. For example, NR3C1 CpG3 had an expected increase of 0.03-fold for each additional 1 ppm of prenatal MeHg (B = 0.030, 95% CI 0.001, 0.059; p = 0.047). Several CpG sites associated with MeHg are located in transcription factor binding sites and the observed methylation changes are predicted to lead to lower gene expression.ConclusionsIn a population of people who consume large amounts of fish, we showed that higher prenatal MeHg exposure was associated with differential DNA methylation at seven years of age at specific CpG sites that may influence neurodevelopment and mental health.
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| 17. |
- Cediel-Ulloa, Andrea, et al.
(författare)
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The C17.2 cell line as testing system for endocrine disruption-induced developmental neurotoxicity
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Hormone signaling plays an essential role during fetal life and is vital for brain development. Endocrine-disrupting chemicals (EDCs) can interfere with the hormonal milieu in this critical time period, disrupting key neurodevelopmental processes. Hence, there is a need for the development of assays that evaluate developmental neurotoxicity (DNT) induced by an endocrine mode of action. Herein, we evaluated the applicability of the neural progenitor C17. 2 cell-line, as an in vitro test method to aid in the detection of endocrine disruption induced DNT. For this, C17.2 cells were exposed during 10 days of differentiation to (ant)agonists of the thyroid hormone (Thr), glucocorticoid (Gr), retinoic acid (Rar), retinoic x (Rxr), oxysterols (Lxr), estrogen (Er), androgen (Ar), and peroxisome proliferator activated delta (Ppard) receptors, as well as to the agonist of the vitamin D (Vdr) receptor. Upon exposure and differentiation, the cells were incubated with Hoechst (nuclear staining) and subsequently stained for βIII-tubulin (neuronal marker) by immunofluorescence. Automated imaging was carried out with a 10X objective lens using an ImageXpress micro xls system (Molecular Devices) and image analysis was performed with MetaXpress® software (Molecular Devices). The C17.2 cells were responsive to the Rar and Rxr agonists which decreased neurite outgrowth, branching and neuronal differentiation as well as to the Rar antagonist which increased neurite outgrowth and branching. With this approach, we have identified that the C17.2 cells are responsive to Gr, Rar, Rxr, and Pparβ/δ, hence contributing to the development of reliable and transferable test methods for hazard assessment of EDCs.
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| 18. |
- Cediel-Ulloa, Andrea, et al.
(författare)
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The pesticides endosulfan and cypermethrin affect neuronal differentiation via retinoic and peroxisome proliferator receptor activity
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Brain development is highly dependent on hormonal homeostasis, hence developmental exposure to endocrine disrupting chemicals (EDCs) is of high concern. In fact, epidemiological and in vivo studies support associations between exposure to EDCs and impaired neurodevelopment. However, the existing hazard assessment of EDCs does not consider developmental neurotoxicity (DNT) prompting an urgent requirement for innovative testing and screening tools addressing endocrine disruption (ED)-induced DNT. We have previously shown the applicability of the immortalized murine neural progenitor cells, C17.2 cells, for addressing ED-DNT. We evidenced decreased neurite outgrowth and branching when the cells were exposed to the Rar, Rxr or Pparβ/δ agonists, and concluded that this is a suitable model for the evaluation of ED-induced DNT for chemicals disrupting Rar, Rxr or Pparβ/δ signalling. In this study we further validated the C17.2 method by testing the effects of 25 EDCs on the same neuronal morphology endpoints as reported in the previous paper. Out of the tested chemicals, endosulfan and cypermethrin decreased, while benzyl butyl phthalate (BBzP) increased neurite outgrowth and branching. We proceeded to evaluate whether these effects were mediated by Rar, Rxr or Ppar β/δ agonism. The neuronal morphology effects of endosulfan and cypermethrin were rescued by co-exposures Rar and Rxr antagonists, and partially rescued by the Ppar β/δ antagonist indicating a common mechanism. With this approach, we have identified that the C17.2 cells can be used as an in vitro model to address ED-induced DNT.
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| 19. |
- Cotgreave, Ian, et al.
(författare)
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Pyriproxifen and microcephaly: an investigation of potential ties to the ongoing "Zika epidemic"
- 2016
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- As part of the Swetox mission to react to emerging concerns in chemical health and environmental safety, a preliminary litterature investigation was undertaken to gather all readily available scientific information on PPF with respect to safety assessment, in order to better understand potential links between chemical exposure and the devopment of microcephaly in affected areas. Therefore the contents of the report do not constitute an attempt at either questioning the use of existing regulatory data in the manner prescribed by international regulatory proceedures, or as a new risk assessment, based on the scientific information and concepts discussed. Here we report our findings, with particular emphasis on exisiting regulatory information, potential for lack of translation of results from regulatory animal testing to humans, lack of human exposure data and suggestions on plausible mode(s) of action of PPF in human neurodevelopmental adversities such as microcephaly.
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| 20. |
- De Castelbajac, Thalia, et al.
(författare)
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Innovative tools and methods for toxicity testing within PARC work package 5 on hazard assessment
- 2023
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Ingår i: Frontiers in Toxicology. - : Frontiers Media S.A.. - 2673-3080. ; 5
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Forskningsöversikt (refereegranskat)abstract
- New approach methodologies (NAMs) have the potential to become a major component of regulatory risk assessment, however, their actual implementation is challenging. The European Partnership for the Assessment of Risks from Chemicals (PARC) was designed to address many of the challenges that exist for the development and implementation of NAMs in modern chemical risk assessment. PARC's proximity to national and European regulatory agencies is envisioned to ensure that all the research and innovation projects that are initiated within PARC agree with actual regulatory needs. One of the main aims of PARC is to develop innovative methodologies that will directly aid chemical hazard identification, risk assessment, and regulation/policy. This will facilitate the development of NAMs for use in risk assessment, as well as the transition from an endpoint-based animal testing strategy to a more mechanistic-based NAMs testing strategy, as foreseen by the Tox21 and the EU Chemical's Strategy for Sustainability. This work falls under work package 5 (WP5) of the PARC initiative. There are three different tasks within WP5, and this paper is a general overview of the five main projects in the Task 5.2 'Innovative Tools and methods for Toxicity Testing,' with a focus on Human Health. This task will bridge essential regulatory data gaps pertaining to the assessment of toxicological prioritized endpoints such as non-genotoxic carcinogenicity, immunotoxicity, endocrine disruption (mainly thyroid), metabolic disruption, and (developmental and adult) neurotoxicity, thereby leveraging OECD's and PARC's AOP frameworks. This is intended to provide regulatory risk assessors and industry stakeholders with relevant, affordable and reliable assessment tools that will ultimately contribute to the application of next-generation risk assessment (NGRA) in Europe and worldwide.
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| 21. |
- Di Criscio, Michela, et al.
(författare)
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A human-relevant mixture of endocrine disrupting chemicals induces changes in hippocampal DNA methylation correlating with hyperactive behavior in male mice
- 2023
-
Ingår i: Chemosphere. - : Elsevier. - 0045-6535 .- 1879-1298. ; 313
-
Tidskriftsartikel (refereegranskat)abstract
- Humans are ubiquitously exposed to endocrine disrupting chemicals (EDCs), substances that interfere with endogenous hormonal signaling. Exposure during early development is of particular concern due to the programming role of hormones during this period. A previous epidemiological study has shown association between prenatal co-exposure to 8 EDCs (Mixture N1) and language delay in children, suggesting an effect of this mixture on neurodevelopment. Furthermore, in utero exposure to Mixture N1 altered gene expression and behavior in adult mice. In this study, we investigated whether epigenetic mechanisms could underlie the long term effects of Mixture N1 on gene expression and behavior. To this end, we analyzed DNA methylation at regulatory regions of genes whose expression was affected by Mixture N1 in the hippocampus of in utero exposed mice using bisulfite-pyrosequencing. We show that Mixture N1 decreases DNA methylation in males at three genes that are part of the hypothalamus-pituitary-adrenal (HPA) axis: Nr3c1, Nr3c2, and Crhr1, coding for the glucocorticoid receptor, the mineralocorticoid receptor, and the corticotropin releasing hormone receptor 1, respectively. Furthermore, we show that the decrease in Nr3c1 methylation correlates with increased gene expression, and that Nr3c1, Nr3c2, and Crhr1 methylation correlates with hyperactivity and reduction in social behavior. These findings indicate that an EDC mixture corresponding to a human exposure scenario induces epigenetic changes, and thus programming effects, on the HPA axis that are reflected in the behavioral phenotypes of the adult male offspring.
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| 22. |
- Drakvik, E., et al.
(författare)
-
Statement on advancing the assessment of chemical mixtures and their risks for human health and the environment
- 2020
-
Ingår i: Environment International. - : Elsevier BV. - 0160-4120 .- 1873-6750. ; 134
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Tidskriftsartikel (refereegranskat)abstract
- The number of anthropogenic chemicals, manufactured, by-products, metabolites and abiotically formed transformation products, counts to hundreds of thousands, at present. Thus, humans and wildlife are exposed to complex mixtures, never one chemical at a time and rarely with only one dominating effect. Hence there is an urgent need to develop strategies on how exposure to multiple hazardous chemicals and the combination of their effects can be assessed. A workshop, “Advancing the Assessment of Chemical Mixtures and their Risks for Human Health and the Environment” was organized in May 2018 together with Joint Research Center in Ispra, EU-funded research projects and Commission Services and relevant EU agencies. This forum for researchers and policy-makers was created to discuss and identify gaps in risk assessment and governance of chemical mixtures as well as to discuss state of the art science and future research needs. Based on the presentations and discussions at this workshop we want to bring forward the following Key Messages: • We are at a turning point: multiple exposures and their combined effects require better management to protect public health and the environment from hazardous chemical mixtures. • Regulatory initiatives should be launched to investigate the opportunities for all relevant regulatory frameworks to include prospective mixture risk assessment and consider combined exposures to (real-life) chemical mixtures to humans and wildlife, across sectors. • Precautionary approaches and intermediate measures (e.g. Mixture Assessment Factor) can already be applied, although, definitive mixture risk assessments cannot be routinely conducted due to significant knowledge and data gaps. • A European strategy needs to be set, through stakeholder engagement, for the governance of combined exposure to multiple chemicals and mixtures. The strategy would include research aimed at scientific advancement in mechanistic understanding and modelling techniques, as well as research to address regulatory and policy needs. Without such a clear strategy, specific objectives and common priorities, research, and policies to address mixtures will likely remain scattered and insufficient. © 2019 The Authors
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| 23. |
- Engdahl, Elin, et al.
(författare)
-
Bisphenol A Inhibits the Transporter Function of the Blood-Brain Barrier by Directly Interacting with the ABC Transporter Breast Cancer Resistance Protein (BCRP)
- 2021
-
Ingår i: International Journal of Molecular Sciences. - : MDPI. - 1661-6596 .- 1422-0067. ; 22:11
-
Tidskriftsartikel (refereegranskat)abstract
- The breast cancer resistance protein (BCRP) is an important efflux transporter in the blood-brain barrier (BBB), protecting the brain from a wide range of substances. In this study, we investigated if BCRP function is affected by bisphenol A (BPA), a high production volume chemical used in common consumer products, as well as by bisphenol F (BPF) and bisphenol S (BPS), which are used to substitute BPA. We employed a transwell-based in vitro cell model of iPSC-derived brain microvascular endothelial cells, where BCRP function was assessed by measuring the intracellular accumulation of its substrate Hoechst 33342. Additionally, we used in silico modelling to predict if the bisphenols could directly interact with BCRP. Our results showed that BPA significantly inhibits the transport function of BCRP. Additionally, BPA was predicted to bind to the cavity that is targeted by known BCRP inhibitors. Taken together, our findings demonstrate that BPA inhibits BCRP function in vitro, probably by direct interaction with the transporter. This effect might contribute to BPA's known impact on neurodevelopment.
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| 24. |
- Engdahl, Elin, et al.
(författare)
-
Childhood adversity increases methylation in the GRIN2B gene
- 2021
-
Ingår i: Journal of Psychiatric Research. - : American Chemical Society (ACS). - 0022-3956 .- 1879-1379. ; 132, s. 38-43
-
Tidskriftsartikel (refereegranskat)abstract
- Childhood adversity is an early life stressor associated with increased risk of several psychiatric disorders such as depression. Epigenetic changes, primarily DNA methylation, can be affected by early life stress, which in turn might contribute to altered disease susceptibility later in life. One plausible biomarker of early life stress is methylation of the ionotropic glutamate receptor NMDA type subunit 2B (GRIN2B) gene, which has been previously shown to be epigenetically affected by prenatal environmental stressors. Here, we set out to investigate if stress-inducing adversity during childhood is associated with changes in methylation of GRIN2B in adulthood. We studied 186 individuals from a Swedish naturalistic population-based cohort who had provided saliva samples (DNA) as well as information regarding both childhood adversity (CA) and depressive symptoms (dep) (nCA,dep = 41, nCA,no-dep = 56, nno-CA,dep = 40, Nno-CA,no-dep = 49). Methylation at four CpG sites in a regulatory region of GRIN2B was analysed using bisulfite pyrosequencing. Associations for methylation status to childhood adversity and to depression status were investigated using linear regression models. Our study shows that childhood adversity is associated with increased methylation levels of GRIN2B in adulthood, for three of the measured CpGs (p = 0.007, 0.006 and 5 × 10−14). This indicates that GRIN2B methylation is susceptible to early life stress, and that methylation at this gene is persistent over time. No association was found between GRIN2B methylation and depression status. Yet, this does not rule out a role for alterations in GRIN2B methylation for other neuropsychological outcomes not studied here.
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| 25. |
- Engdahl, Elin, et al.
(författare)
-
DNA methylation at GRIN2B partially mediates the association between prenatal bisphenol F exposure and cognitive functions in 7-year-old children in the SELMA study
- 2021
-
Ingår i: Environment International. - : Elsevier. - 0160-4120 .- 1873-6750. ; 156
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Accumulating evidence suggests that prenatal chemical exposure triggers epigenetic modifications that could influence health outcomes later in life. In this study, we investigated whether DNA methylation (DNAm) levels at the glutamate ionotropic receptor NMDA type subunit 2B (GRIN2B) gene underlies the association between prenatal exposure to an endocrine disrupting chemical (EDC), bisphenol F (BPF), and lower cognitive functions in 7-year-old children. Methods: Data from 799 children participating in the Swedish Environmental Longitudinal Mother and child Asthma and allergy (SELMA) pregnancy cohort was analyzed. Prenatal BPF exposure was assessed by measuring BPF levels in maternal urine. At age 7, DNAm of three CpG sites in a regulatory region of the GRIN2B gene was analyzed from buccal swabs using bisulfite-Pyrosequencing. Cognitive functions, including full-scale IQ and four subscales, were evaluated using the Wechsler Intelligence Scale for Children (WISC-IV). Associations between prenatal BPF exposure and GRIN2B DNAm, as well as between GRIN2B DNAm and cognitive functions, were determined using regression models adjusted for potential confounders. Generalized structural equation models (gSEM) were used to evaluate if GRIN2B DNAm mediates the association between prenatal BPF exposure and cognitive functions at 7 years of age. Results: Prenatal BPF exposure was positively associated with GRIN2B DNAm levels at the third CpG site (CpG3), while CpG3 methylation was inversely associated with cognitive test scores. Mediation analyses showed that CpG3 methylation exerted 6–9% of the association between BPF exposure and full-scale IQ, as well as verbal comprehension and perceptual reasoning in boys, while not significant in girls. Conclusions: This study is the first to identify locus-specific DNAm as a mediating factor underlying an epidemiological association between prenatal EDC exposure and cognitive functions in childhood. It also confirms previous findings, that GRIN2B DNAm is responsive to environmental exposures.
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| 26. |
- Engdahl, Elin, et al.
(författare)
-
Prenatal Exposure to Endocrine Disrupting Chemicals and Their Effect on Health Later in Life
- 2020
-
Ingår i: Beyond Our Genes. - Cham : Springer Nature. - 9783030352134 - 9783030352127 ; , s. 53-77
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Evidence is increasing that chemical exposure significantly contributes to human ill health. This chapter focuses on endocrine disrupting chemicals (EDCs), a group of substances that interfere with our endogenous hormonal system. Exposure to EDCs, in particular during pre- and early postnatal development, has been associated with a number of disorders such as decreased fertility, hormone-related cancers, as well as neurodevelopmental and metabolic disorders. EDCs differ from classical toxicants in several ways, they can for example affect the organism already at very low doses and introduce long-term changes that manifest much later in life. Such effects could be mediated by epigenetic changes. Indeed, a large number of experimental studies have shown that EDCs can induce epigenetic changes, in particular alteration in DNA methylation. This is corroborated by some epidemiological studies where epigenetic changes were linked to EDC exposure. In this chapter, we introduce examples of EDCs, their exposure sources and modes of actions, and summarize the evidence for their effects on the epigenome in relation to their impact on fertility, neurodevelopment, and metabolism.
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| 27. |
- Fallet, Manon, 1992-, et al.
(författare)
-
Present and future challenges for the investigation of transgenerational epigenetic inheritance
- 2023
-
Ingår i: Environment International. - : Elsevier. - 0160-4120 .- 1873-6750. ; 172
-
Forskningsöversikt (refereegranskat)abstract
- Epigenetic pathways are essential in different biological processes and in phenotype-environment interactions in response to different stressors and they can induce phenotypic plasticity. They encompass several processes that are mitotically and, in some cases, meiotically heritable, so they can be transferred to subsequent generations via the germline. Transgenerational Epigenetic Inheritance (TEI) describes the phenomenon that phenotypic traits, such as changes in fertility, metabolic function, or behavior, induced by environmental factors (e.g., parental care, pathogens, pollutants, climate change), can be transferred to offspring generations via epigenetic mecha-nisms. Investigations on TEI contribute to deciphering the role of epigenetic mechanisms in adaptation, adver-sity, and evolution. However, molecular mechanisms underlying the transmission of epigenetic changes between generations, and the downstream chain of events leading to persistent phenotypic changes, remain unclear. Therefore, inter-, (transmission of information between parental and offspring generation via direct exposure) and transgenerational (transmission of information through several generations with disappearance of the triggering factor) consequences of epigenetic modifications remain major issues in the field of modern biology.In this article, we review and describe the major gaps and issues still encountered in the TEI field: the general challenges faced in epigenetic research; deciphering the key epigenetic mechanisms in inheritance processes; identifying the relevant drivers for TEI and implement a collaborative and multi-disciplinary approach to study TEI. Finally, we provide suggestions on how to overcome these challenges and ultimately be able to identify the specific contribution of epigenetics in transgenerational inheritance and use the correct tools for environmental science investigation and biomarkers identification.
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| 28. |
- Hallberg, Ida, et al.
(författare)
-
Bovine oocyte exposure to perfluorohexane sulfonate (PFHxS) induces phenotypic, transcriptomic, and DNA methylation changes in resulting embryos in vitro
- 2022
-
Ingår i: Reproductive Toxicology. - : Elsevier. - 0890-6238 .- 1873-1708. ; 109, s. 19-30
-
Tidskriftsartikel (refereegranskat)abstract
- Knowledge on the effects of perfluorohexane sulfonate (PFHxS) on ovarian function is limited. In the current study, we investigated the sensitivity of oocytes to PFHxS during in vitro maturation (IVM), including conse-quences on embryo development at the morphological, transcriptomic, and epigenomic levels. Bovine cumulus-oocyte complexes (COCs) were exposed to PFHxS during 22 h IVM. Following fertilisation, developmental competence was recorded until day 8 of culture. Two experiments were conducted: 1) exposure of COCs to 0.01 mu g mL(-1) -100 mu g mL(-1) PFHxS followed by confocal imaging to detect neutral lipids and nuclei, and 2) exposure of COCs to 0.1 mu g mL(-1) PFHxS followed by analysis of transcriptomic and DNA methylation changes in blastocysts. Decreased oocyte developmental competence was observed upon exposure to & nbsp;>= 40 mu g mL(-1) PFHxS and altered lipid distribution was observed in the blastocysts upon exposure to 1-10 mu g mL(-1) PFHxS (not observed at lower or higher concentrations). Transcriptomic data showed that genes affected by 0.1 mu g mL(-1) PFHxS were enriched for pathways related to increased synthesis and production of reactive oxygen species. Enrichment for peroxisome proliferator-activated receptor-gamma and oestrogen pathways was also observed. Genes linked to DNA methylation changes were enriched for similar pathways. In conclusion, exposure of the bovine oocyte to PFHxS during the narrow window of IVM affected subsequent embryonic development, as reflected by morphological and mo- lecular changes. This suggests that PFHxS interferes with the final nuclear and cytoplasmic maturation of the oocyte leading to decreased developmental competence to blastocyst stage.
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| 29. |
- Hallberg, Ida, et al.
(författare)
-
Perfluorooctane sulfonate (PFOS) exposure of bovine oocytes affects early embryonic development at human-relevant levels in an in vitro model
- 2021
-
Ingår i: Toxicology. - : Elsevier. - 0300-483X .- 1879-3185. ; 464
-
Tidskriftsartikel (refereegranskat)abstract
- Perfluorooctane sulfonate (PFOS) has been added to Stockholm Convention for global phase out, but will continue to contribute to the chemical burden in humans for a long time to come due to extreme persistence in the environment. In the body, PFOS is transferred into to the ovarian follicular fluid that surrounds the maturing oocyte. In the present study, bovine cumulus oocyte complexes were exposed to PFOS during 22 h in vitro maturation. Concentrations of 2 ng g(-1) (PFOS-02) representing average human exposure and 53 ng g(-1) (PFOS-53) relevant to highly exposed groups were used. After exposure, developmental competence was recorded until day 8 after fertilisation. Blastocysts were fixed and either stained to evaluate blastomere number and lipid distribution using confocal microscopy or frozen and pooled for microarray-based gene expression and DNA methylation analyses. PFOS-53 delayed the first cleavage to two-cell stage and beyond at 44 h after fertilisation (p < .01). No reduction of proportion blastocysts were seen at day 8 in either of the groups, but PFOS-53 exposure resulted in delayed development into more advanced stages of blastocysts seen as both reduced developmental stage (p = .001) and reduced number of blastomeres (p = .04). Blastocysts showed an altered lipid distribution that was more pronounced after exposure to PFOS-53 (increased total lipid volume, p=.0003, lipid volume/cell p < .0001) than PFOS-02, where only decreased average lipid droplet size (p=.02) was observed. Gene expression analyses revealed pathways differently regulated in the PFOS-treated groups compared to the controls, which were related to cell death and survival through e.g., P38 mitogen-activated protein kinases and signal transducer and activator of transcription 3, which in turn activates tumour protein 53 (TP53). Transcriptomic changes were also associated with metabolic stress response, differentiation and proliferation, which could help to explain the phenotypic changes seen in the blastocysts. The gene expression changes were more pronounced after exposure to PFOS-53 compared to PFOS-02. DNA-methylation changes were associated with similar biological functions as the transcriptomic data, with the most significantly associated pathway being TP53. Collectively, these results reveal that brief PFOS exposure during oocyte maturation alters the early embryo development at concentrations relevant to humans. This study adds to the evidence that PFOS has the potential to affect female fertility.
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| 30. |
- Hases, Linnea
(författare)
-
Estrogen signaling in colon inflammation and colorectal cancer
- 2020
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Colorectal cancer (CRC) is the third most deadly form of cancer in the Western world. Although screening efforts have reduced the overall mortality, the incidence is increasing among young adults. The frequency of inflammatory bowel disease (IBD) and obesity are increasing in parallel, which suggest a common underlying environmental link between the conditions. This increase is thought to correlate to an increased intake of high fat diets, and obesity is a major risk factor for CRC. Chronic inflammation, which is a hallmark for CRC promotion, is a well-known underlying factor in both obesity and IBD. The gut microbiota is another hallmark, and an impaired relationship between the host and gut microbes can contribute to obesity, IBD and CRC. The risk-benefit balance of current CRC-preventative treatments is poor, and there is a need for safer and better preventatives in order to reduce the CRC mortality. Both obesity and IBD place men at a significant higher risk of CRC compared to women. This indicates a protective role for estrogen. The use of full Estrogen receptor (ER) β knockout mice has demonstrated ERβ protective effects against experimentally induced CRC. However, it is unknown through which cells these protective effects are mediated. There are only low mRNA levels of ERβ in the colon, unclear if adequate for a functional role, and ERβ may also be expressed in intestinal immune cells. Understanding the CRC-preventative effects of intestinal epithelial ERβ in both sexes is important and may provide the background for a novel CRC chemopreventive approach.The overall aim of the thesis is the functional characterization of intestinal epithelial ERβ during colon inflammation and colitis-induced CRC and identification of potential sex differences, which can ultimately provide novel opportunities for chemopreventive exploitation (Figure 1). In paper I we utilized intestinal epithelial ERβ knockout mice (ERβKOVil) of both sexes and induced colitis and colitis associated CRC (CA-CRC). We found that intestinal epithelial ERβ is protective against colitis and CA-CRC in both sexes, but in a sex-dependent manner. The underlying mechanism includes an intricate crosstalk with TNFα-induced NFκB signaling.In paper II we identify that both sex and intestinal epithelial ERβ impact the microbiota composition. This may contribute to the exacerbated colitis and colitis-induced tumor formation observed in ERβKOVil mice.In paper III we induced colon inflammation by feeding the mice a high-fat diet (HFD, 60%) for 13 weeks and explored treatment with estrogen receptor-selective ligands. We identified that estrogen signaling, via ERβ, modulated the HFD-induced changes in the colon microenvironment. This included sex-dependent effects on epithelial cell proliferation, macrophage infiltration, and regulation of core circadian clock gene expression.In paper IV we utilized paired-normal and CRC clinical samples and identified sex differences in the transcriptome of both normal colon and CRC. By applying data-driven feature selection and machine learning on sex-separated TCGA data, we proposed sex-specific diagnostic biomarkers and prognostic biomarkers using survival analysis. In summary, this thesis characterizes intestinal epithelial ERβ as a novel chemopreventative target for CA-CRC in both sexes, and identifies related biological pathways, including crosstalk with nuclear factor κB (NFκB) signaling and modulation of circadian clock genes. ERβ activity in intestinal epithelial cells is manifested by altered microbiota composition, cell proliferation and immune cell infiltration. The identification of several significant sex differences provides evidence for the need to take sex into account in colitis and CRC research to improve health interventions.
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| 31. |
- Hokfelt, Tomas, et al.
(författare)
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Neuropeptide and Small Transmitter Coexistence: Fundamental Studies and Relevance to Mental Illness
- 2018
-
Ingår i: Frontiers in Neural Circuits. - : FRONTIERS MEDIA SA. - 1662-5110. ; 12
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Forskningsöversikt (refereegranskat)abstract
- Neuropeptides are auxiliary messenger molecules that always co-exist in nerve cells with one or more small molecule (classic) neurotransmitters. Neuropeptides act both as transmitters and trophic factors, and play a role particularly when the nervous system is challenged, as by injury, pain or stress. Here neuropeptides and coexistence in mammals are reviewed, but with special focus on the 29/30 amino acid galanin and its three receptors GalR1, -R2 and -R3. In particular, galanins role as a co-transmitter in both rodent and human noradrenergic locus coeruleus (LC) neurons is addressed. Extensive experimental animal data strongly suggest a role for the galanin system in depression-like behavior. The translational potential of these results was tested by studying the galanin system in postmortem human brains, first in normal brains, and then in a comparison of five regions of brains obtained from depressed people who committed suicide, and from matched controls. The distribution of galanin and the four galanin system transcripts in the normal human brain was determined, and selective and parallel changes in levels of transcripts and DNA methylation for galanin and its three receptors were assessed in depressed patients who committed suicide: upregulation of transcripts, e.g., for galanin and GalR3 in LC, paralleled by a decrease in DNA methylation, suggesting involvement of epigenetic mechanisms. It is hypothesized that, when exposed to severe stress, the noradrenergic LC neurons fire in bursts and release galanin from their soma/dendrites. Galanin then acts on somato-dendritic, inhibitory galanin autoreceptors, opening potassium channels and inhibiting firing. The purpose of these autoreceptors is to act as a brake to prevent overexcitation, a brake that is also part of resilience to stress that protects against depression. Depression then arises when the inhibition is too strong and long lasting - a maladaption, allostatic load, leading to depletion of NA levels in the forebrain. It is suggested that disinhibition by a galanin antagonist may have antidepressant activity by restoring forebrain NA levels. A role of galanin in depression is also supported by a recent candidate gene study, showing that variants in genes for galanin and its three receptors confer increased risk of depression and anxiety in people who experienced childhood adversity or recent negative life events. In summary, galanin, a neuropeptide coexisting in LC neurons, may participate in the mechanism underlying resilience against a serious and common disorder, MDD. Existing and further results may lead to an increased understanding of how this illness develops, which in turn could provide a basis for its treatment.
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| 32. |
- Krebs, Alice, et al.
(författare)
-
Template for the Description of Cell-Based Toxicological Test Methods to Allow Evaluation and Regulatory Use of the Data
- 2019
-
Ingår i: Altex. - : ALTEX Edition. - 1868-596X .- 1868-8551. ; 36:4, s. 682-699
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Only few cell-based test methods are described by Organisation for Economic Co-operation and Development (OECD) test guidelines or other regulatory references (e.g., the European Pharmacopoeia). The majority of toxicity tests still falls into the category of non-guideline methods. Data from these tests may nevertheless be used to support regulatory decisions or to guide strategies to assess compounds (e.g., drugs, agrochemicals) during research and development if they fulfill basic requirements concerning their relevance, reproducibility and predictivity. Only a method description of sufficient clarity and detail allows interpretation and use of the data. To guide regulators faced with increasing amounts of data from non-guideline studies, the OECD formulated Guidance Document 211 (GD211) on method documentation for the purpose of safety assessment. As GD211 is targeted mainly at regulators, it leaves scientists less familiar with regulation uncertain as to what level of detail is required and how individual questions should be answered. Moreover, little attention was given to the description of the test system (i.e., cell culture) and the steps leading to it being established in the guidance. To address these issues, an annotated toxicity test method template (ToxTemp) was developed (i) to fulfill all requirements of GD211, (ii) to guide the user concerning the types of answers and detail of information required, (iii) to include acceptance criteria for test elements, and (iv) to define the cells sufficiently and transparently. The fully annotated ToxTemp is provided here, together with reference to a database containing exemplary descriptions of more than 20 cell-based tests.
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| 33. |
- Lizunkova, Polina, et al.
(författare)
-
A Mixture of Endocrine Disrupting Chemicals Associated with Lower Birth Weight in Children Induces Adipogenesis and DNA Methylation Changes in Human Mesenchymal Stem Cells
- 2022
-
Ingår i: International Journal of Molecular Sciences. - : MDPI. - 1661-6596 .- 1422-0067. ; 23:4
-
Tidskriftsartikel (refereegranskat)abstract
- Endocrine Disrupting Chemicals (EDCs) are man-made compounds that alter functions of the endocrine system. Environmental mixtures of EDCs might have adverse effects on human health, even though their individual concentrations are below regulatory levels of concerns. However, studies identifying and experimentally testing adverse effects of real-life mixtures are scarce. In this study, we aimed at evaluating an epidemiologically identified EDC mixture in an experimental setting to delineate its cellular and epigenetic effects. The mixture was established using data from the Swedish Environmental Longitudinal Mother and child Asthma and allergy (SELMA) study where it was associated with lower birth weight, an early marker for prenatal metabolic programming. This mixture was then tested for its ability to change metabolic programming of human mesenchymal stem cells. In these cells, we assessed if the mixture induced adipogenesis and genome-wide DNA methylation changes. The mixture increased lipid droplet accumulation already at concentrations corresponding to levels measured in the pregnant women of the SELMA study. Furthermore, we identified differentially methylated regions in genes important for adipogenesis and thermogenesis. This study shows that a mixture reflecting human real-life exposure can induce molecular and cellular changes during development that could underlie adverse outcomes.
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| 34. |
- Lizunkova, Polina, et al.
(författare)
-
A Mixture of Endocrine Disrupting Chemicals Associated with Lower Birth Weight Induces Adipogenesis and Transcriptional Changes in Human Mesenchymal Stem Cells.
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- There are concerns about the involvement of endocrine-disrupting chemicals (EDCs) exposure in the development of metabolic disorders and obesity. Humans are continuously exposed to complex mixtures of EDCs. This study examined effects of a human-relevant EDC mixture on cellular and underlying molecular changes in human mesenchymal stem cells (hMSCs). The EDC mixture consisted of nine chemicals from different classes. Prenatal exposure to this mixture in a previously published epidemiological study was negatively associated with birth weight, an early risk marker for development of metabolic diseases later in life. hMSCs were treated with this mixture in human-relevant concentrations. Adipogenesis was assessed via lipid droplet accumulation assay, while transcriptional changes were assessed by RNA-seq. The exposure to this mixture increased lipid droplet accumulation and gene expression of over 1000 genes, both in dose-dependent manner in hMSCs. The genes that were found to be upregulated by the EDC mixture were associated with cell division. We did not observe upregulation of adipogenesis related genes, however, some of the downregulated genes are known to be involved in osteogenic MSCs differentiation. Additionally, the EDC mixture affected expression of genes that were enriched in corticoid-regulated categories, including some that are known to be involved in osteogenic MSCs differentiation. Our findings demonstrate that a human-relevant EDC exposure can increase adipogenesis as well as possibly alter the balance between adipogenesis and osteogenesis of MSCs. These processes are essential during metabolic programming, hence our results emphasize the role of a human-relevant EDCs as potential metabolic disruptors and potential contributors to the global metabolic disorder epidemic.
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| 35. |
- Lizunkova, Polina, et al.
(författare)
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Additivity provides a good approximation for the effect of a complex, human-relevant chemical mixture on metabolic outcomes
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Humans and the environment are exposed to complex mixtures of numerous synthetic chemicals. This study investigated whether the additivity model could predict effects of a human-relevant complex chemical mixture. The additivity model analysis was conducted on toxicological data from two experimental models exposed to the mixture and its individual compounds. The chemical mixture was previously identified in an epidemiological study to be associated with lower birth weight. This mixture consisted of 14 fourteen chemicals from different classes. Gompertz nonlinear function was used for individual compound and mixture analysis. We showed that the additivity model provided an adequate and larger estimate for mixture effects for both experimental assays in comparison to the measured effects, despite for one of the assays the test for additivity was rejected. Our results underscore dose addition model applicability for regulatory risk assessment of complex human-relevant chemical mixtures.
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| 36. |
- Lizunkova, Polina
(författare)
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Impact of epidemiologically identified mixtures of endocrine disrupting chemicals on metabolic programming
- 2023
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- We are ubiquitously exposed to a plethora of endocrine-disrupting chemicals (EDCs), i.e. substances that alter the function(s) of the endocrine system. While ample evidence show individual EDC's influence on developmental processes resulting in adverse health outcomes, less is known about the effects of human-relevant EDC mixtures exposure. Additionally, there is a lack of appropriate methodology to assess the hazard and risk of complex mixtures.This doctoral project aimed to examine the effects of two EDC mixtures and to compare individual components to its mixture, on the developing metabolic system. And to investigate additivity approach for predicting effects of complex mixtures. Studied EDC mixtures (G and G1) were previously identified using Swedish Environmental Longitudinal Mother and Child Asthma and Allergy (SELMA) study data, based on their association with lower birth weight. In this thesis, these mixtures, and mixture G1’s components, were tested for effects on adipogenesis and underlying epigenetic and transcriptional changes in human mesenchymal stem cells (hMSCs) and on metabolic rate in zebrafish larvae.In hMSCs, both mixtures induced adipogenesis at concentrations corresponding to SELMA cohort measured levels. Mixture G induced early transcriptional changes of over 1000 genes in a dose-dependent manner. These genes significantly overlapped with glucocorticoid-regulated genes and were involved in early osteogenesis. Mixture G1 induced significant DNA methylation changes at 713 positions and in six genomic regions in genes whose expression or methylation was previously associated with obesity or MSC differentiation. In zebrafish larvae, mixture G1 increased oxygen consumption rate. Compared to mixture G1, none of its individual components showed equally large effects on adipogenesis or metabolic rate. However, mixture G1 effect on both endpoints could be adequately predicted by the additivity model using experimental data from its constituents.In conclusion, this doctoral project showed that mixtures corresponding to human real-life exposures, in terms of proportions and concentrations, can induce molecular, cellular, and whole-organism changes relevant to developmental metabolic programming, which could underlie adverse outcomes later in life. The results emphasise that mixtures matter and should be accounted for in regulatory risk assessments, and provide support for additivity models as a pragmatic approach to mixture risk assessment.
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| 37. |
- Lupu, Diana, et al.
(författare)
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Endocrine Disrupting Chemicals and Hippocampal Development : The Role of Estrogen and Androgen Signalling
- 2023
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Ingår i: Neuroendocrinology. - : S. Karger. - 0028-3835 .- 1423-0194. ; 113:12, s. 1193-1214
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Tidskriftsartikel (refereegranskat)abstract
- Hormones are important regulators of key processes during fetal brain development. Thus, the developing brain is vulnerable to the action of chemicals that can interfere with endocrine signals. Epidemiological studies have pointed toward sexually dimorphic associations between neurodevelopmental outcomes, such as cognitive abilities, in children and prenatal exposure to endocrine disrupting chemicals (EDCs). This points toward disruption of sex steroid signalling in the development of neural structures underlying cognitive functions, such as the hippocampus, an essential mediator of learning and memory processes. Indeed, during development, the hippocampus is subjected to the organizational effects of estrogens and androgens, which influence hippocampal cell proliferation, differentiation, dendritic growth and synaptogenesis in the hippocampal fields of Cornu Ammonis and the dentate gyrus. These early organizational effects correlate with a sexual dimorphism in spatial cognition and are subject to exogenous chemical perturbations. This review summarises the current knowledge about the organizational effects of estrogens and androgens on the developing hippocampus and the evidence for hippocampal-dependent learning and memory perturbations induced by developmental exposure to EDCs. We conclude that, while it is clear that sex hormone signalling plays a significant role during hippocampal development, a complete picture at the molecular and cellular levels would be needed to establish causative links between the endocrine modes of action exerted by EDCs and the adverse outcomes these chemicals can induce at the organism level.
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| 38. |
- Lupu, Diana, et al.
(författare)
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Fluoxetine Affects Differentiation of Midbrain Dopaminergic Neurons In Vitro
- 2018
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Ingår i: Molecular Pharmacology. - New York : American Society for Pharmacology and Experimental Therapeutics. - 0026-895X .- 1521-0111. ; 94:4, s. 1220-1231
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Tidskriftsartikel (refereegranskat)abstract
- Recent meta-analyses found an association between prenatal exposure to the antidepressant fluoxetine (FLX) and an increased risk of autism in children. This developmental disorder has been related to dysfunctions in the brains' rewards circuitry, which, in turn, has been linked to dysfunctions in dopaminergic (DA) signaling. The present study investigated if FLX affects processes involved in dopaminergic neuronal differentiation. Mouse neuronal precursors were differentiated into midbrain dopaminergic precursor cells (mDPCs) and concomitantly exposed to clinically relevant doses of FLX. Subsequently, dopaminergic precursors were evaluated for expression of differentiation and stemness markers using quantitative polymerase chain reaction. FLX treatment led to increases in early regional specification markers orthodenticle homeobox 2 (Otx2) and homeobox engrailed-1 and -2 (En1 and En2). On the other hand, two transcription factors essential for midbrain dopaminergic (mDA) neurogenesis, LIM homeobox transcription factor 1 alpha (Lmx1a) and paired-like homeodomain transcription factor 3 (Pitx3) were downregulated by FLX treatment. The stemness marker nestin (Nes) was increased, whereas the neuronal differentiation marker beta 3-tubulin (Tubb3) decreased. Additionally, we observed that FLX modulates the expression of several genes associated with autism spectrum disorder and downregulates the estrogen receptors (ERs) alpha and beta. Further investigations using ER beta knockout (BERKO) mDPCs showed that FLX had no or even opposite effects on several of the genes analyzed. These findings suggest that FLX affects differentiation of the dopaminergic system by increasing production of dopaminergic precursors, yet decreasing their maturation, partly via interference with the estrogen system.
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| 39. |
- Lupu, Diana, et al.
(författare)
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The ENDpoiNTs Project : Novel Testing Strategies for Endocrine Disruptors Linked to Developmental Neurotoxicity
- 2020
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Ingår i: International Journal of Molecular Sciences. - : MDPI. - 1661-6596 .- 1422-0067. ; 21:11
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Tidskriftsartikel (refereegranskat)abstract
- Ubiquitous exposure to endocrine-disrupting chemicals (EDCs) has caused serious concerns about the ability of these chemicals to affect neurodevelopment, among others. Since endocrine disruption (ED)-induced developmental neurotoxicity (DNT) is hardly covered by the chemical testing tools that are currently in regulatory use, the Horizon 2020 research and innovation action ENDpoiNTs has been launched to fill the scientific and methodological gaps related to the assessment of this type of chemical toxicity. The ENDpoiNTs project will generate new knowledge about ED-induced DNT and aims to develop and improve in vitro, in vivo, and in silico models pertaining to ED-linked DNT outcomes for chemical testing. This will be achieved by establishing correlative and causal links between known and novel neurodevelopmental endpoints and endocrine pathways through integration of molecular, cellular, and organismal data from in vitro and in vivo models. Based on this knowledge, the project aims to provide adverse outcome pathways (AOPs) for ED-induced DNT and to develop and integrate new testing tools with high relevance for human health into European and international regulatory frameworks.
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| 40. |
- Marini, Daniele, et al.
(författare)
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Pilot survey reveals ophidiomycosis in dice snakes Natrix tessellata from Lake Garda, Italy
- 2023
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Ingår i: Veterinary research communications. - : Springer. - 0165-7380 .- 1573-7446. ; 47:3, s. 1707-1719
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Tidskriftsartikel (refereegranskat)abstract
- Ophidiomycosis is an emerging infectious disease caused by the fungus Ophidiomyces ophidiicola (Oo). To date, Oo presence or associated disease condition has been recorded in wild and/or captive snakes from North America, Europe, Asia and Australia, but the data is still scarce outside the Nearctic. Although Italy is a country with a high snake biodiversity in the European panorama, and animals with clinical signs compatible with Oo infection have been documented, to date no investigations have reported the disease in the wild. Therefore, a pilot survey for the Italian territory was performed in conjunction with setting up a complete diagnostic workflow including SYBR Green-based real-time PCR assay for the detection of Oo genomic and mitochondrial DNA combined with histopathology of scale clips. Oo presence was investigated in 17 wild snake specimens from four different species. Four snakes were sampled in a targeted location where the mycosis was suspected via citizen science communications (i.e. North of the Lake Garda), whereas other ophidians were collected following opportunistic sampling. Oo genomic and mitochondrial DNA were detected and sequenced from all four Lake Garda Natrix tessellata, including three juveniles with macroscopic signs such as discolouration and skin crusts. From histopathological examination of scale clips, the three young positive individuals exhibited ulceration, inflammation and intralesional hyphae consistent with Oo infection, and two of them also showed the presence of arthroconidial tufts and solitary cylindrical arthrospores, allowing "Ophidiomycosis and Oo shedder" categorisation. For the remaining snake samples, the real-time PCR tested negative for Oo. This pilot survey permitted to localise for the first time Oo infection in free-ranging ophidians from Italy. Ophidiomycosis from Lake Garda highlights the need to increase sampling efforts in this area as well as in other northern Italian lakes to assess the occurrence of the pathogen, possible risk factors of the infection, its impact on host population fitness and the disease ecology of Oo in European snakes.
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| 41. |
- Meng, Weida, et al.
(författare)
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Genotype-dependent epigenetic regulation of DLGAP2 in alcohol use and dependence
- 2021
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Ingår i: Molecular Psychiatry. - : Springer Nature. - 1359-4184 .- 1476-5578. ; 26:8, s. 4367-4382
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Tidskriftsartikel (refereegranskat)abstract
- Alcohol misuse is a major public health problem originating from genetic and environmental risk factors. Alterations in the brain epigenome may orchestrate changes in gene expression that lead to alcohol misuse and dependence. Through epigenome-wide association analysis of DNA methylation from human brain tissues, we identified a differentially methylated region, DMR-DLGAP2, associated with alcohol dependence. Methylation within DMR-DLGAP2 was found to be genotype-dependent, allele-specific and associated with reward processing in brain. Methylation at the DMR-DLGAP2 regulated expression of DLGAP2 in vitro, and Dlgap2-deficient mice showed reduced alcohol consumption compared with wild-type controls. These results suggest that DLGAP2 may be an interface for genetic and epigenetic factors controlling alcohol use and dependence.
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| 42. |
- Nalvarte, Ivan, et al.
(författare)
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The expression and activity of thioredoxin reductase 1 splice variants v1 and v2 regulate the expression of genes associated with differentiation and adhesion
- 2015
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Ingår i: Bioscience Reports. - : PORTLAND PRESS LTD. - 0144-8463 .- 1573-4935. ; 35:e00269
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Tidskriftsartikel (refereegranskat)abstract
- The mammalian redox-active selenoprotein thioredoxin reductase (TrxR1) is a main player in redox homoeostasis. It transfers electrons from NADPH to a large variety of substrates, particularly to those containing redox-active cysteines. Previously, we reported that the classical form of cytosolic TrxR1 (TXNRD1_v1), when overexpressed in human embryonic kidney cells (HEK-293), prompted the cells to undergo differentiation [Nalvarte et al. (2004) J. Biol. Chem. 279, 54510-54517]. In the present study, we show that several genes associated with differentiation and adhesion are differentially expressed in HEK-293 cells stably overexpressing TXNRD1_v1 compared with cells expressing its splice variant TXNRD1_v2. Overexpression of these two splice forms resulted in distinctive effects on various aspects of cellular functions including gene regulation patterns, alteration of growth rate, migration and morphology and susceptibility to selenium-induced toxicity. Furthermore, differentiation of the neuroblastoma cell line SH-SY5Y induced by all-trans retinoic acid (ATRA) increased both TXNRD1_v1 and TXNRD1_v2 expressions along with several of the identified genes associated with differentiation and adhesion. Selenium supplementation in the SH-SY5Y cells also induced a differentiated morphology and changed expression of the adhesion protein fibronectin 1 and the differentiation marker cadherin 11, as well as different temporal expression of the studied TXNRD1 variants. These data suggest that both TXNRD1_v1 and TXNRD1_v2 have distinct roles in differentiation, possibly by altering the expression of the genes associated with differentiation, and further emphasize the importance in distinguishing each unique action of different TrxR1 splice forms, especially when studying the gene silencing or knockout of TrxR1.
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| 43. |
- Repouskou, Anastasia, et al.
(författare)
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Long term transcriptional and behavioral effects in mice developmentally exposed to a mixture of endocrine disruptors associated with delayed human neurodevelopment
- 2020
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Ingår i: Scientific Reports. - : Nature Publishing Group. - 2045-2322. ; 10, s. 1-8
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Tidskriftsartikel (refereegranskat)abstract
- Accumulating evidence suggests that gestational exposure to endocrine disrupting chemicals (EDCs) may interfere with normal brain development and predispose for later dysfunctions. The current study focuses on the exposure impact of mixtures of EDCs that better mimics the real-life situation. We herein describe a mixture of phthalates, pesticides and bisphenol A (mixture N1) detected in pregnant women of the SELMA cohort and associated with language delay in their children. To study the long-term impact of developmental exposure to N1 on brain physiology and behavior we administered this mixture to mice throughout gestation at doses 0x, 0.5x, 10x, 100x and 500x the geometric mean of SELMA mothers' concentrations, and examined their offspring in adulthood. Mixture N1 exposure increased active coping during swimming stress in both sexes, increased locomotion and reduced social interaction in male progeny. The expression of corticosterone receptors, their regulator Fkbp5, corticotropin releasing hormone and its receptor, oxytocin and its receptor, estrogen receptor beta, serotonin receptors (Htr1a, Htr2a) and glutamate receptor subunit Grin2b, were modified in the limbic system of adult animals, in a region-specific, sexually-dimorphic and experience-dependent manner. Principal component analysis revealed gene clusters associated with the observed behavioral responses, mostly related to the stress axis. This integration of epidemiology-based data with an experimental model increases the evidence that prenatal exposure to EDC mixtures impacts later life brain functions.
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| 44. |
- Sapounidou, Maria, et al.
(författare)
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From Cohort to Cohort : A Similar Mixture Approach (SMACH) to Evaluate Exposures to a Mixture Leading to Thyroid-Mediated Neurodevelopmental Effects Using NHANES Data
- 2023
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Ingår i: Toxics. - : MDPI. - 2305-6304. ; 11:4
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Tidskriftsartikel (refereegranskat)abstract
- Prenatal exposure to a mixture (MIX N) of eight endocrine-disrupting chemicals has been associated with language delay in children in a Swedish pregnancy cohort. A novel approach was proposed linking this epidemiological association with experimental evidence, where the effect of MIX N on thyroid hormone signaling was assessed using the Xenopus eleuthero-embryonic thyroid assay (XETA OECD TG248). From this experimental data, a point of departure (PoD) was derived based on OECD guidance. Our aim in the current study was to use updated toxicokinetic models to compare exposures of women of reproductive age in the US population to MIX N using a Similar Mixture Approach (SMACH). Based on our findings, 66% of women of reproductive age in the US (roughly 38 million women) had exposures sufficiently similar to MIX N. For this subset, a Similar Mixture Risk Index (SMRIHI) was calculated comparing their exposures to the PoD. Women with SMRIHI > 1 represent 1.1 million women of reproductive age. Older women, Mexican American and other/multi race women were less likely to have high SMRIHI values compared to Non-Hispanic White women. These findings indicate that a reference mixture of chemicals identified in a Swedish cohort—and tested in an experimental model for establishment of (PoDs)—is also of health relevance in a US population.
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| 45. |
- Skott, Elin, et al.
(författare)
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Effects of a synbiotic on symptoms, and daily functioning in attention deficit hyperactivity disorder - A double-blind randomized controlled
- 2020
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Ingår i: Brain, behavior, and immunity. - : Elsevier BV. - 0889-1591 .- 1090-2139. ; 89, s. 9-19
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Tidskriftsartikel (refereegranskat)abstract
- Some prebiotics and probiotics have been proposed to improve psychiatric symptoms in children with autism. However, few studies were placebo-controlled, and there is no study on persons with an attention deficit hyperactivity disorder (ADHD) diagnosis. Our aim was to study effects of Synbiotic 2000 on psychiatric symptoms and functioning in children and adults with ADHD without an autism diagnosis. Children and adults (n = 182) with an ADHD diagnosis completed the nine weeks randomized double-blind parallel placebo-controlled trial examining effects of Synbiotic 2000 on the primary endpoints ADHD symptoms, autism symptoms and daily functioning, and the secondary endpoint emotion regulation, measured using the questionnaires SNAP-IV, ASRS, WFIRS, SCQ, AQ and DERS-16. Levels at baseline of plasma C-reactive protein and soluble vascular cell adhesion molecule-1 (sVCAM-1), central to leukocyte-endothelial cell adhesion facilitating inflammatory responses in tissues, were measured using Meso Scale Discovery. Synbiotic 2000 and placebo improved ADHD symptoms equally well, and neither active treatment nor placebo had any statistically significant effect on functioning or sub-diagnostic autism symptoms. However, Synbiotic 2000, specifically, reduced sub-diagnostic autism symptoms in the domain restricted, repetitive and stereotyped behaviors in children, and improved emotion regulation in the domain of goal-directed behavior in adults. In children with elevated sVCAM-1 levels at baseline as well as in children without ADHD medication, Synbiotic 2000 reduced both the total score of autism symptoms, and the restricted, repetitive and stereotyped behaviors. In adults with elevated sVCAM-1 at baseline, Synbiotic 2000 significantly improved emotion regulation, both the total score and four of the five subdomains. To conclude, while no definite Synbiotic 2000-specific effect was detected, the analysis of those with elevated plasma sVCAM-1 levels proposed a reduction of autism symptoms in children and an improvement of emotion regulation in adults with ADHD.Trial registration number: ISRCTN57795429.
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| 46. |
- Tal, Tamara, et al.
(författare)
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New approach methods to assess developmental and adult neurotoxicity for regulatory use : a PARC work package 5 project
- 2024
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Ingår i: Frontiers in Toxicology. - : Frontiers Media S.A.. - 2673-3080. ; 6
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Tidskriftsartikel (refereegranskat)abstract
- In the European regulatory context, rodent in vivo studies are the predominant source of neurotoxicity information. Although they form a cornerstone of neurotoxicological assessments, they are costly and the topic of ethical debate. While the public expects chemicals and products to be safe for the developing and mature nervous systems, considerable numbers of chemicals in commerce have not, or only to a limited extent, been assessed for their potential to cause neurotoxicity. As such, there is a societal push toward the replacement of animal models with in vitro or alternative methods. New approach methods (NAMs) can contribute to the regulatory knowledge base, increase chemical safety, and modernize chemical hazard and risk assessment. Provided they reach an acceptable level of regulatory relevance and reliability, NAMs may be considered as replacements for specific in vivo studies. The European Partnership for the Assessment of Risks from Chemicals (PARC) addresses challenges to the development and implementation of NAMs in chemical risk assessment. In collaboration with regulatory agencies, Project 5.2.1e (Neurotoxicity) aims to develop and evaluate NAMs for developmental neurotoxicity (DNT) and adult neurotoxicity (ANT) and to understand the applicability domain of specific NAMs for the detection of endocrine disruption and epigenetic perturbation. To speed up assay time and reduce costs, we identify early indicators of later-onset effects. Ultimately, we will assemble second-generation developmental neurotoxicity and first-generation adult neurotoxicity test batteries, both of which aim to provide regulatory hazard and risk assessors and industry stakeholders with robust, speedy, lower-cost, and informative next-generation hazard and risk assessment tools.
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| 47. |
- Tay, Nicole, et al.
(författare)
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Allele-Specific Methylation of SPDEF : A Novel Moderator of Psychosocial Stress and Substance Abuse
- 2019
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Ingår i: American Journal of Psychiatry. - : AMER PSYCHIATRIC PUBLISHING, INC. - 0002-953X .- 1535-7228. ; 176:2, s. 146-155
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Psychosocial stress is a key risk factor for substance abuse among adolescents. Recently, epigenetic processes such as DNA methylation have emerged as potential mechanisms that could mediate this relationship. The authors conducted a genome-wide methylation analysis to investigate whether differentially methylated regions are associated with psychosocial stress in an adolescent population.Methods: A methylome-wide analysis of differentially methylated regions was used to examine a sample of 1,287 14-year-old adolescents (50.7% of them female) from the European IMAGEN study. The Illumina 450k array was used to assess DNA methylation, pyrosequencing was used for technical replication, and linear regression analyses were used to identify associations with psychosocial stress and substance use (alcohol and tobacco). Findings were replicated by pyrosequencing a test sample of 413 participants from the IMAGEN study.Results: Hypermethylation in the sterile alpha motif/pointed domain containing the ETS transcription factor (SPDEF) gene locus was associated with a greater number of stressful life events in an allele-dependent way. Among individuals with the minor G-allele, SPDEF methylation moderated the association between psychosocial stress and substance abuse. SPDEF methylation interacted with lifetime stress in gray matter volume in the right cuneus, which in turn was associated with the frequency of alcohol and tobacco use. SPDEF was involved in the regulation of trans-genes linked to substance use.Conclusions: Taken together, the study findings describe a novel epigenetic mechanism that helps explain how psychosocial stress exposure influences adolescent substance abuse.
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| 48. |
- Wennemo, Tova, et al.
(författare)
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A human-relevant complex mixture affects metabolic endpoints in human mesenchymal stem cells and zebrafish (Danio rerio) differently than its single compounds
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- As a result of extensive use of endocrine disrupting chemicals (EDCs) in everyday products, humans are continuously exposed to mixtures of EDCs. This study employed an EDC mixture that was negatively associated with birth weight in a previously published population based study. We examined and compared the metabolic effects at human-relevant concentrations of this EDC mixture and its individual chemicals in human mesenchymal stem cells (hMSCs) and in zebrafish larvae. Adipogenesis in hMSCs was measured in a lipid droplet accumulation assay while metabolic rate in zebrafish larvae was measured in an oxygen consumption assay. In this study we show that a human-relevant EDC mixture, in terms of composition and concentrations, increased both lipid droplet accumulation as well as oxygen consumption of hMSCs and zebrafish larvae, respectively. These increases were greater in magnitude than any of the mixture's individual components. In the adipogenesis assay, from the 14 individual chemicals composing the mixture, only exposure to monoethylhexyl phthalate (MEHP) resulted in a statistically significant effect which was in the same direction as the mixture's effect. In the respirometry assay exposure to only two individual chemicals resulted in statistically significant effects. One of these chemicals, perfluorooctane sulfonate (PFOS) changed oxygen consumption in the same manner as the mixture while the second chemical, monobenzyl phthalate (MBzP) resulted in an opposite effect to the mixture. Our findings identified individual chemical drivers of the mixture effects in the lipid droplet accumulation and oxygen consumption assays. Additionally, we underscore the significance of understanding effects of complex mixtures that reflect real-life exposures as well as including mixture effects in chemical hazard and risk assessment.
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| 49. |
- Xiao, Linhong, et al.
(författare)
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Zeitotox : Toxicology and the Rhythms of Life
- 2022
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Ingår i: Environmental Science and Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 56:16, s. 11100-11102
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 50. |
- Özel, Fatih, et al.
(författare)
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DNA methylation at DLGAP2 and risk for relapse in alcohol dependence during acamprosate treatment
- 2024
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Ingår i: Drug And Alcohol Dependence. - : Elsevier. - 0376-8716 .- 1879-0046. ; 256
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Tidskriftsartikel (refereegranskat)abstract
- Background: Alcohol use disorders are prevalent mental disorders with significant health implications. Epigenetic alterations may play a role in their pathogenesis, as DNA methylation at several genes has been associated with these disorders. We have previously shown that methylation in the DLGAP2 gene, coding for a synaptic density protein, is associated with alcohol dependence. In this study, we aimed to examine the association between DLGAP2 methylation and treatment response among patients undergoing acamprosate treatment. Methods: 102 patients under acamprosate treatment were included. DNA methylation analysis at DLGAP2 was performed by bisulfite pyrosequencing at the start and after 3 -month treatment. Treatment outcomes were having a relapse during the treatment and severity of craving at the end of three months. Cox proportional hazard and linear regression models were performed. Results: Patients whose methylation levels were decreased during the treatment showed an increased risk for relapse within three months in comparison to the ones without methylation change (hazard ratio [HR]=2.44; 95% confidence interval [CI]=1.04, 5.73; p=0.04). For the same group, a positive association for the severity of craving was observed, yet statistical significance was not reached (beta=2.97; 95% CI= -0.41, 6.34; p=0.08). Conclusion: We demonstrate that patients whose DLGAP2 methylation levels decrease during acamprosate treatment are more likely to relapse compared to the ones without changes. This is in line with our previous findings showing that DLGAP2 methylation is lower in alcohol dependent subjects compared to controls, and might suggest a role for changes in DLGAP2 methylation in treatment response.
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