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Yu G, Wu L, Su Q, Ji X, Zhou J, Wu S, Tang Y, Li H. Neurotoxic effects of heavy metal pollutants in the environment: Focusing on epigenetic mechanisms. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 345:123563. [PMID: 38355086 DOI: 10.1016/j.envpol.2024.123563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Revised: 02/04/2024] [Accepted: 02/11/2024] [Indexed: 02/16/2024]
Abstract
The pollution of heavy metals (HMs) in the environment is a significant global environmental issue, characterized by its extensive distribution, severe contamination, and profound ecological impacts. Excessive exposure to heavy metal pollutants can damage the nervous system. However, the mechanisms underlying the neurotoxicity of most heavy metals are not completely understood. Epigenetics is defined as a heritable change in gene function that can influence gene and subsequent protein expression levels without altering the DNA sequence. Growing evidence indicates that heavy metals can induce neurotoxic effects by triggering epigenetic changes and disrupting the epigenome. Compared with genetic changes, epigenetic alterations are more easily reversible. Epigenetic reprogramming techniques, drugs, and certain nutrients targeting specific epigenetic mechanisms involved in gene expression regulation are emerging as potential preventive or therapeutic tools for diseases. Therefore, this review provides a comprehensive overview of epigenetic modifications encompassing DNA/RNA methylation, histone modifications, and non-coding RNAs in the nervous system, elucidating their association with various heavy metal exposures. These primarily include manganese (Mn), mercury (Hg), lead (Pb), cobalt (Co), cadmium (Cd), nickel (Ni), sliver (Ag), toxic metalloids arsenic (As), and etc. The potential epigenetic mechanisms in the etiology, precision prevention, and target therapy of various neurodevelopmental disorders or different neurodegenerative diseases are emphasized. In addition, the current gaps in research and future areas of study are discussed. From a perspective on epigenetics, this review offers novel insights for prevention and treatment of neurotoxicity induced by heavy metal pollutants.
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Affiliation(s)
- Guangxia Yu
- Key Lab of Environment and Health, School of Public Health, Fujian Medical University, Fuzhou 350122, China; Department of Preventive Medicine, School of Public Health, Fujian Medical University, Fuzhou 350122, China
| | - Lingyan Wu
- Key Lab of Environment and Health, School of Public Health, Fujian Medical University, Fuzhou 350122, China
| | - Qianqian Su
- Key Lab of Environment and Health, School of Public Health, Fujian Medical University, Fuzhou 350122, China
| | - Xianqi Ji
- Key Lab of Environment and Health, School of Public Health, Fujian Medical University, Fuzhou 350122, China
| | - Jinfu Zhou
- Key Lab of Environment and Health, School of Public Health, Fujian Medical University, Fuzhou 350122, China; Fujian Maternity and Child Hospital College of Clinical Medicine for Obstetrics & Gynecology and Pediatrics, Fujian Medical University, Fuzhou 350001, China
| | - Siying Wu
- Key Lab of Environment and Health, School of Public Health, Fujian Medical University, Fuzhou 350122, China; Department of Epidemiology and Health Statistics, School of Public Health, Fujian Medical University, Fuzhou 350122, China
| | - Ying Tang
- Fujian Center for Prevention and Control Occupational Diseases and Chemical Poisoning, Fuzhou 350125, China
| | - Huangyuan Li
- Key Lab of Environment and Health, School of Public Health, Fujian Medical University, Fuzhou 350122, China; Department of Preventive Medicine, School of Public Health, Fujian Medical University, Fuzhou 350122, China.
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Medina S, Zhang QY, Lauer FT, Santos-Medina LV, Factor-Litvak P, Islam T, Eunus M, Rahman M, Uddin MN, Liu KJ, Parvez F. Arsenic exposure is associated with alterations to multiple red blood cell parameters among adults in rural Bangladesh. Toxicol Appl Pharmacol 2024; 484:116858. [PMID: 38341105 PMCID: PMC11069126 DOI: 10.1016/j.taap.2024.116858] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 01/25/2024] [Accepted: 02/07/2024] [Indexed: 02/12/2024]
Abstract
Chronic arsenic exposures are associated with multiple hematologic disturbances, including anemia. The goal of this study was to evaluate associations between arsenic exposures and hematological parameters among men and women who are chronically exposed to elevated levels of arsenic from drinking water. Hematologic analyses were performed on blood collected from 755 participants (45% male and 54% female) in the Health Effects of Arsenic Longitudinal Study (HEALS) cohort, Bangladesh. Herein, we used linear regression models to estimate associations between red blood cell (RBC) parameters (i.e., RBC counts, hematocrit (HCT), hemoglobin (Hgb), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), and mean corpuscular hemoglobin concentration (MCHC)) and measurements of arsenic exposure (urinary arsenic and urinary arsenic metabolites). Arsenic exposures showed trending associations with decreased RBC counts in both men and women, a positive association with MCV in males, and an inverse association with MCHC among males, but not among non-smoking females. Among men, those who smoked had stronger associations between arsenic exposures and MCHC than non-smoking males. Collectively, our results show that arsenic exposures affect multiple RBC parameters and highlight potentially important sex differences in arsenic-induced hematotoxicity.
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Affiliation(s)
- Sebastian Medina
- The University of New Mexico College of Pharmacy, Department of Pharmaceutical Sciences, Albuquerque, NM 87131, USA; New Mexico Highlands University, Department of Biology, Las Vegas, NM 87701, USA
| | - Qian-Yun Zhang
- The University of New Mexico School of Medicine, Department of Pathology, Albuquerque, NM 87131, USA
| | - Fredine T Lauer
- The University of New Mexico College of Pharmacy, Department of Pharmaceutical Sciences, Albuquerque, NM 87131, USA
| | - Laura V Santos-Medina
- The University of New Mexico College of Pharmacy, Department of Pharmaceutical Sciences, Albuquerque, NM 87131, USA; New Mexico Highlands University, Department of Biology, Las Vegas, NM 87701, USA
| | - Pam Factor-Litvak
- Department of Epidemiology, Mailman School of Public Health, Columbia University, New York, NY 10032, USA
| | - Tariqul Islam
- University of Chicago and Columbia University Field Research Office, Dhaka 1230, Bangladesh
| | - Mahbubul Eunus
- University of Chicago and Columbia University Field Research Office, Dhaka 1230, Bangladesh
| | - Mizanour Rahman
- University of Chicago and Columbia University Field Research Office, Dhaka 1230, Bangladesh
| | - Mohammad Nasir Uddin
- Department of Biochemistry and Molecular Biology, Mawlana Bhashani Science and Technology, Santosh, Tangail 1902, Bangladesh
| | - Ke Jian Liu
- The University of New Mexico College of Pharmacy, Department of Pharmaceutical Sciences, Albuquerque, NM 87131, USA; Stony Brook University, Department of Pathology, Stony Brook, NY 11794, USA.
| | - Faruque Parvez
- Mailman University School of Public Health, Department of Environmental Health Sciences, Columbia University, New York, NY 10032, USA.
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Mondal R, Pal P, Biswas S, Chattopadhyay A, Bandyopadhyay A, Mukhopadhyay A, Mukhopadhyay PK. Attenuation of sodium arsenite mediated ovarian DNA damage, follicular atresia, and oxidative injury by combined application of vitamin E and C in post pubertal Wistar rats. NAUNYN-SCHMIEDEBERG'S ARCHIVES OF PHARMACOLOGY 2023; 396:2701-2720. [PMID: 37129605 DOI: 10.1007/s00210-023-02491-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Accepted: 04/11/2023] [Indexed: 05/03/2023]
Abstract
Arsenic being a toxic metalloid ubiquitously persists in environment and causes several health complications including female reproductive anomalies. Epidemiological studies documented birth anomalies due to arsenic exposure. Augmented reactive oxygen species (ROS) generation and quenched antioxidant pool are foremost consequences of arsenic threat. On the contrary, Vitamin E (VE) and C (VC) are persuasive antioxidants and conventionally used in toxicity management. Present study was designed to explore the extent of efficacy of combined VE and VC (VEC) against Sodium arsenite (NaAsO2) mediated ovarian damage. Thirty-six female Wistar rats were randomly divided into three groups (Grs) and treated for consecutive 30 days; Gr I (control) was vehicle fed, Gr II (treated) was gavaged with NaAsO2 (3 mg/kg/day), Gr III (supplement) was provided with VE (400 mg/kg/day) & VC (200 mg/kg/day) along with NaAsO2. Marked histological alterations were evidenced by disorganization in oocyte, granulosa cells and zona pellucida layers in treated group. Considerable reduction of different growing follicles along with increased atretic follicles was noted in treated group. Altered activities ofΔ5 3β-Hydroxysteroid dehydrogenase and 17β-Hydroxysteroid dehydrogenase accompanied by reduced luteinizing hormone, follicle-stimulating hormone and estradiol levels were observed in treated animals. Irregular estrous cyclicity pattern was also observed due to NaAsO2 threat. Surplus ROS production affected ovarian antioxidant strata as evidenced by altered oxidative stress markers. Provoked oxidative strain further affects DNA status of ovary. However, supplementation with VEC caused notable restoration from such disparaging effects of NaAsO2 toxicities. Antioxidant and antiapoptotic attributes of those vitamins might be liable for such restoration.
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Affiliation(s)
- Rubia Mondal
- Department of Life Sciences, Presidency University, Kolkata, India
| | - Priyankar Pal
- Department of Life Sciences, Presidency University, Kolkata, India
| | - Sagnik Biswas
- Department of Life Sciences, Presidency University, Kolkata, India
| | - Alok Chattopadhyay
- Department of Physiology, Harimohan Ghose College, Affiliated to University of Calcutta, Kolkata, India
| | - Amit Bandyopadhyay
- Sports and Exercise Physiology Laboratory, Department of Physiology, University Colleges of Science & Technology, University of Calcutta, Kolkata, India
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Rychlik KA, Illingworth EJ, Sanchez IF, Attreed SE, Sinha P, Casin KM, Taube N, Loube J, Tasneen R, Kabir R, Nuermberger E, Mitzner W, Kohr MJ, Sillé FCM. Long-term effects of prenatal arsenic exposure from gestational day 9 to birth on lung, heart, and immune outcomes in the C57BL/6 mouse model. Toxicol Lett 2023; 383:17-32. [PMID: 37244563 PMCID: PMC10527152 DOI: 10.1016/j.toxlet.2023.05.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 04/21/2023] [Accepted: 05/22/2023] [Indexed: 05/29/2023]
Abstract
Prenatal arsenic exposure is a major public health concern, associated with altered birth outcomes and increased respiratory disease risk. However, characterization of the long-term effects of mid-pregnancy (second trimester) arsenic exposure on multiple organ systems is scant. This study aimed to characterize the long-term impact of mid-pregnancy inorganic arsenic exposure on the lung, heart, and immune system, including infectious disease response using the C57BL/6 mouse model. Mice were exposed from gestational day 9 till birth to either 0 or 1000 µg/L sodium (meta)arsenite in drinking water. Male and female offspring assessed at adulthood (10-12 weeks of age) did not show significant effects on recovery outcomes after ischemia reperfusion injury but did exhibit increased airway hyperresponsiveness compared to controls. Flow cytometric analysis revealed significantly greater total numbers of cells in arsenic-exposed lungs, lower MHCII expression in natural killer cells, and increased percentages of dendritic cell populations. Activated interstitial (IMs) and alveolar macrophages (AMs) isolated from arsenic-exposed male mice produced significantly less IFN-γ than controls. Conversely, activated AMs from arsenic-exposed females produced significantly more IFN-γ than controls. Although systemic cytokine levels were higher upon Mycobacterium tuberculosis (Mtb) infection in prenatally arsenic-exposed offspring there was no difference in lung Mtb burden compared to controls. This study highlights significant long-term impacts of prenatal arsenic exposure on lung and immune cell function. These effects may contribute to the elevated risk of respiratory diseases associated with prenatal arsenic exposure in epidemiology studies and point to the need for more research into mechanisms driving these maintained responses.
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Affiliation(s)
- Kristal A Rychlik
- Department of Environmental Health and Engineering, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA; Public Health Program, School of Exercise and Sport Science, University of Mary Hardin-Baylor, Belton, TX, USA
| | - Emily J Illingworth
- Department of Environmental Health and Engineering, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | - Ian F Sanchez
- Department of Environmental Health and Engineering, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | - Sarah E Attreed
- Department of Environmental Health and Engineering, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA; Foreign Animal Disease Research Unit, USDA/ARS Plum Island Animal Disease Center, Plum Island, CT, USA
| | - Prithvi Sinha
- Department of Environmental Health and Engineering, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | - Kevin M Casin
- Department of Environmental Health and Engineering, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | - Nicole Taube
- Department of Environmental Health and Engineering, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | - Jeff Loube
- Department of Environmental Health and Engineering, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | - Rokeya Tasneen
- Center for Tuberculosis Research, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Raihan Kabir
- Department of Environmental Health and Engineering, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | - Eric Nuermberger
- Center for Tuberculosis Research, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Wayne Mitzner
- Department of Environmental Health and Engineering, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | - Mark J Kohr
- Department of Environmental Health and Engineering, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | - Fenna C M Sillé
- Department of Environmental Health and Engineering, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA.
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Cao J, Chen Y, Wang H. 11β-hydroxysteroid dehydrogenases and biomarkers in fetal development. Toxicology 2022; 479:153316. [PMID: 36096318 DOI: 10.1016/j.tox.2022.153316] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 08/29/2022] [Accepted: 09/07/2022] [Indexed: 11/27/2022]
Abstract
It is known that basal glucocorticoid levels in utero are essential for regulating fetal development and maturation, and determine the fate of later life. Recently, more and more studies suggest that adverse prenatal environments may cause abnormal maternal glucocorticoid levels in utero. 11β-hydroxysteroid dehydrogenases (11β-HSDs) are widely distributed in the target organs of glucocorticoids (GCs) and mineralocorticoids. 11β-HSDs is involved in fetal physiological and pathological development by activating or inactivating GCs. Prenatal adverse environments (including exogenous and maternal environments) can affect the expression and activity of 11β-HSDs in the placenta and fetus via multiple pathways. It induces abnormal local glucocorticoid levels in fetal multiple tissues, fetal developmental programming and homeostasis changes, and the susceptibility to various diseases after birth. We also discuss the interventions of 11β-HSDs inhibitors on fetal developmental programming and susceptibility to multiple diseases. Finally, we propose that 11β-HSD2 can be used as a molecular target for fetal developmental toxicity, while 11β-HSD1 can be regarded as an intervention target to prevent fetal-originated diseases. This review will provide a theoretical basis for the early prevention and treatment of fetal-originated diseases.
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Affiliation(s)
- Jiangang Cao
- Department of Pharmacology, Wuhan University Taikang Medical School (School of Basic Medical Sciences), Wuhan 430071, China
| | - Yawen Chen
- Department of Pharmacology, Wuhan University Taikang Medical School (School of Basic Medical Sciences), Wuhan 430071, China
| | - Hui Wang
- Department of Pharmacology, Wuhan University Taikang Medical School (School of Basic Medical Sciences), Wuhan 430071, China; Hubei Provincial Key Laboratory of Developmentally Originated Disease, Wuhan 430071, China.
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Application of the adverse outcome pathway concept for investigating developmental neurotoxicity potential of Chinese herbal medicines by using human neural progenitor cells in vitro. Cell Biol Toxicol 2022; 39:319-343. [PMID: 35701726 PMCID: PMC10042984 DOI: 10.1007/s10565-022-09730-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Accepted: 05/10/2022] [Indexed: 12/16/2022]
Abstract
Adverse outcome pathways (AOPs) are organized sequences of key events (KEs) that are triggered by a xenobiotic-induced molecular initiating event (MIE) and summit in an adverse outcome (AO) relevant to human or ecological health. The AOP framework causally connects toxicological mechanistic information with apical endpoints for application in regulatory sciences. AOPs are very useful to link endophenotypic, cellular endpoints in vitro to adverse health effects in vivo. In the field of in vitro developmental neurotoxicity (DNT), such cellular endpoints can be assessed using the human "Neurosphere Assay," which depicts different endophenotypes for a broad variety of neurodevelopmental KEs. Combining this model with large-scale transcriptomics, we evaluated DNT hazards of two selected Chinese herbal medicines (CHMs) Lei Gong Teng (LGT) and Tian Ma (TM), and provided further insight into their modes-of-action (MoA). LGT disrupted hNPC migration eliciting an exceptional migration endophenotype. Time-lapse microscopy and intervention studies indicated that LGT disturbs laminin-dependent cell adhesion. TM impaired oligodendrocyte differentiation in human but not rat NPCs and activated a gene expression network related to oxidative stress. The LGT results supported a previously published AOP on radial glia cell adhesion due to interference with integrin-laminin binding, while the results of TM exposure were incorporated into a novel putative, stressor-based AOP. This study demonstrates that the combination of phenotypic and transcriptomic analyses is a powerful tool to elucidate compounds' MoA and incorporate the results into novel or existing AOPs for a better perception of the DNT hazard in a regulatory context.
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Fitz NF, Barchowsky A, Koldamova R, Lefterov I. Genome-wide Alteration of Histone Methylation Profiles Associated with Cognitive Changes in Response to Developmental Arsenic Exposure in Mice. Toxicol Rep 2022; 9:393-403. [PMID: 35299870 PMCID: PMC8920871 DOI: 10.1016/j.toxrep.2022.03.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 02/16/2022] [Accepted: 03/02/2022] [Indexed: 11/18/2022] Open
Abstract
Inorganic arsenic is a xenobiotic entering the body primarily through contaminated drinking water and food. There are defined mechanisms that describe arsenic’s association with increased cancer incidence, however mechanisms explaining arsenic exposure and neurodevelopmental or aging disorders are poorly defined. In recent years, arsenic effects on epigenome have become a particular focus. We hypothesize that human relevant arsenic exposure during particular developmental windows, or long-term exposure later in life induce pathophysiological neural changes through epigenomic alterations, in particular histone methylation profile, manifesting as cognitive decline. C57BL/6 wild-type mice were continually exposed to sodium arsenite (100 µg/L) in drinking water prior to mating through weaning of the experimental progeny. A second cohort of aged APP/PS mice were chronically exposed to the same level of arsenic. Cognitive testing, histological examination of brains and genome-wide methylation levels of H3K4me3 and H3K27me3 examined after ChIP-seq were used to determine the effects of arsenic exposure. Developmental arsenic exposure caused significantly diminished cognition in wild-type mice. The analysis of ChIP-seq data and experiments with mouse embryonic stem cells demonstrated that epigenetic changes induced by arsenic exposure translated into gene expression alterations associated with neuronal development and neurological disease. Increased hippocampal amyloid plaques levels of APP/PS mice and cognitive decline provided evidence that arsenic exposure aggravated an existing Alzheimer’s disease-like phenotype. We show developmental arsenic exposure significantly impacts histone modifications in brain which remain present into adulthood and provide a potential mechanism by which developmental arsenic exposure influences cognitive functions. We also show that human relevant, chronic arsenic exposure has deleterious effects on adult APP/PS mice and exacerbates existing Alzheimer’s disease-like symptoms. The results demonstrate how developmental arsenic exposure impacts the brain epigenome, leading to altered gene expression later in life. Developmental arsenic exposure impacts biologically significant histone modifications in brain. Decreased trimethylation of H3K27 is associated with processes related to neuron fate and development. Histone modification in brain present a potential mechanism how developmental arsenic exposure impacts cognitive functions. Arsenic exacerbates cognitive deficits and neuroinflammation in AD model mice.
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Muhetaer M, Yang M, Xia R, Lai Y, Wu J. Gender difference in arsenic biotransformation is an important metabolic basis for arsenic toxicity. BMC Pharmacol Toxicol 2022; 23:15. [PMID: 35227329 PMCID: PMC8883647 DOI: 10.1186/s40360-022-00554-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Accepted: 02/02/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Arsenic metabolism enzymes can affect the toxic effects of arsenic. However, the effects of different genders on the metabolites and metabolic enzymes in liver arsenic metabolism is still unclear. This study analyzed the gender differences of various arsenic metabolites and metabolic enzymes and further explored the effects of gender differences on arsenic metabolism in liver tissues of rats. METHODS Rats were treated with high/medium/low doses of iAs3+ or iAs5+. Liver pathological changes were observed with electron microscopy. The monomethyl aracid (MMA) and dimethyl aracid (DMA) was determined by high performance liquid chromatography-hydride generation atomic fluorescence spectroscopy. S-adenosylmethionine (SAM), arsenate respiratory reductase (ARR), nicotinamide adenine dinucleotide (NAD), purine nucleoside phosphorylase (PNP), pyruvate kinase (PK), and myeloperoxidase (MPO) SAM, ARR, NAD, PNP, PK, and MPO were determined by enzyme-linked immunoassay. RT-qPCR was used to determine Arsenic (+ 3 oxidation state) methyltransferase (AS3MT). RESULTS The iAs3+ and iAs5+ at high doses induced pathological changes in the liver, such as increased heterochromatin and lipid droplets. Compared within the same group, MMA and DMA were statistically significant in iAs3 + high, iAs3 + medium and iAs5+ low dose groups (P < 0.05). MMA of male rats in iAs3+ high and medium groups was higher than that of female rats, and the DMA of male rats was lower than that of female rats. As3MT mRNA in the male iAs3+ high group was higher than that of females. Besides, compared between male and female, only in iAS3+ low dose, iAS3+ medium dose, iAS5+ low dose, and iAS5+ medium dose groups, there was significant difference in SAM level (P < 0.05). Compared within the same group, male rats had significantly higher PNP and ARR activities while lower PK activity than female rats (P < 0.05). Between the male and female groups, only the iAS3+ high dose and medium dose group had a statistically significant difference (P < 0.05). The NAD activity of females in iAS3+ high dose group was higher than that of males. CONCLUSION The gender differences in the arsenic metabolism enzymes may affect the biotransformation of arsenic, which may be one of the important mechanisms of arsenic toxicity of different sexes and different target organs.
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Affiliation(s)
- Maihaba Muhetaer
- Department of Occupational Health and Environmental Health, Public Health College of Xinjiang Medical University, No.567, Sunde North Road, Shuimogou District, Xinjiang, 830011, Urumqi, People's Republic of China
| | - Mei Yang
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Xinjiang Medical University, 830011, Urumqi, People's Republic of China
| | - Rongxiang Xia
- Department of Endemic Disease Control, Center for Disease Control and Prevention of Xinjiang Uygur Autonomous Region, 830011, Urumqi, People's Republic of China
| | - Yuanyan Lai
- Department of Occupational Health and Environmental Health, Public Health College of Xinjiang Medical University, No.567, Sunde North Road, Shuimogou District, Xinjiang, 830011, Urumqi, People's Republic of China
| | - Jun Wu
- Department of Occupational Health and Environmental Health, Public Health College of Xinjiang Medical University, No.567, Sunde North Road, Shuimogou District, Xinjiang, 830011, Urumqi, People's Republic of China.
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Gade M, Comfort N, Re DB. Sex-specific neurotoxic effects of heavy metal pollutants: Epidemiological, experimental evidence and candidate mechanisms. ENVIRONMENTAL RESEARCH 2021; 201:111558. [PMID: 34224706 PMCID: PMC8478794 DOI: 10.1016/j.envres.2021.111558] [Citation(s) in RCA: 50] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 05/14/2021] [Accepted: 06/17/2021] [Indexed: 05/19/2023]
Abstract
The heavy metals lead (Pb), mercury (Hg), and cadmium (Cd) are ubiquitous environmental pollutants and are known to exert severe adverse impacts on the nervous system even at low concentrations. In contrast, the heavy metal manganese (Mn) is first and foremost an essential nutrient, but it becomes neurotoxic at high levels. Neurotoxic metals also include the less prevalent metalloid arsenic (As) which is found in excessive concentrations in drinking water and food sources in many regions of the world. Males and females often differ in how they respond to environmental exposures and adverse effects on their nervous systems are no exception. Here, we review the different types of sex-specific neurotoxic effects, such as cognitive and motor impairments, that have been attributed to Pb, Hg, Mn, Cd, and As exposure throughout the life course in epidemiological as well as in experimental toxicological studies. We also discuss differential vulnerability to these metals such as distinctions in behaviors and occupations across the sexes. Finally, we explore the different mechanisms hypothesized to account for sex-based differential susceptibility including hormonal, genetic, metabolic, anatomical, neurochemical, and epigenetic perturbations. An understanding of the sex-specific effects of environmental heavy metal neurotoxicity can aid in the development of more efficient systematic approaches in risk assessment and better exposure mitigation strategies with regard to sex-linked susceptibilities and vulnerabilities.
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Affiliation(s)
- Meethila Gade
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, NY, USA
| | - Nicole Comfort
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, NY, USA
| | - Diane B Re
- Department of Environmental Health Sciences, Mailman School of Public Health, Columbia University, New York, NY, USA; NIEHS Center of Northern Manhattan, Columbia University, New York, NY, USA; Motor Neuron Center for Biology and Disease, Columbia University, New York, NY, USA.
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Prenatal metal mixtures and sex-specific infant negative affectivity. Environ Epidemiol 2021; 5:e147. [PMID: 33870019 PMCID: PMC8043734 DOI: 10.1097/ee9.0000000000000147] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Accepted: 03/04/2021] [Indexed: 11/27/2022] Open
Abstract
Supplemental Digital Content is available in the text. Prenatal exposure to metals has been associated with a range of adverse neurocognitive outcomes; however, associations with early behavioral development are less well understood. We examined joint exposure to multiple co-occurring metals in relation to infant negative affect, a stable temperamental trait linked to psychopathology among children and adults.
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Solomon ER, Caldwell KK, Allan AM. Developmental arsenic exposure is associated with sex differences in the epigenetic regulation of stress genes in the adult mouse frontal cortex. Toxicol Appl Pharmacol 2020; 391:114920. [PMID: 32061746 PMCID: PMC7948303 DOI: 10.1016/j.taap.2020.114920] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 02/06/2020] [Accepted: 02/10/2020] [Indexed: 11/15/2022]
Affiliation(s)
- Elizabeth R Solomon
- Department of Neurosciences, School of Medicine, University of New Mexico HSC, MSC08 4740, 1 University of New Mexico, Albuquerque, NM 87131-0001, United States
| | - Kevin K Caldwell
- Department of Neurosciences, School of Medicine, University of New Mexico HSC, MSC08 4740, 1 University of New Mexico, Albuquerque, NM 87131-0001, United States
| | - Andrea M Allan
- Department of Neurosciences, School of Medicine, University of New Mexico HSC, MSC08 4740, 1 University of New Mexico, Albuquerque, NM 87131-0001, United States.
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Masjosthusmann S, Siebert C, Hübenthal U, Bendt F, Baumann J, Fritsche E. Arsenite interrupts neurodevelopmental processes of human and rat neural progenitor cells: The role of reactive oxygen species and species-specific antioxidative defense. CHEMOSPHERE 2019; 235:447-456. [PMID: 31272005 DOI: 10.1016/j.chemosphere.2019.06.123] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 06/15/2019] [Accepted: 06/16/2019] [Indexed: 05/10/2023]
Abstract
Arsenic exposure disturbs brain development in humans. Although developmental neurotoxicity (DNT) of arsenic has been studied in vivo and in vitro, its mode-of-action (MoA) is not completely understood. Here, we characterize the adverse neurodevelopmental effects of sodium arsenite on developing human and rat neural progenitor cells (hNPC, rNPC). Moreover, we analyze the involvement of reactive oxygen species (ROS) and the role of the glutathione (GSH)-dependent antioxidative defense for arsenite-induced DNT in a species-specific manner. We determined IC50 values for sodium arsenite-dependent (0.1-10 μM) inhibition of hNPC and rNPC migration (6.0 μM; >10 μM), neuronal (2.7 μM; 4.4 μM) and oligodendrocyte (1.1 μM; 2.0 μM) differentiation. ROS involvement was studied by quantifying the expression of ROS-regulated genes, measuring glutathione (GSH) levels, inhibiting GSH synthesis and co-exposing cells to the antioxidant N-acetylcysteine. Arsenite reduces NPC migration, neurogenesis and oligodendrogenesis of differentiating hNPC and rNPC at sub-cytotoxic concentrations. Species-specific arsenite cytotoxicity and induction of antioxidative gene expression is inversely related to GSH levels with rNPC possessing >3-fold the amount of GSH than hNPC. Inhibition of GSH synthesis increased the sensitivity towards arsenite in rNPC > hNPC. N-acetylcysteine antagonized arsenite-mediated induction of HMOX1 expression as well as reduction of neuronal and oligodendrocyte differentiation in hNPC suggesting involvement of oxidative stress in arsenite DNT. hNPC are more sensitive towards arsenite-induced neurodevelopmental toxicity than rNPC, probably due to their lower antioxidative defense capacities. This species-specific MoA data might be useful for adverse outcome pathway generation and future integrated risk assessment strategies concerning DNT.
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Affiliation(s)
- Stefan Masjosthusmann
- IUF - Leibniz Research Institute for Environmental Medicine, Auf'm Hennekamp 50, 40225, Duesseldorf, Germany
| | - Clara Siebert
- IUF - Leibniz Research Institute for Environmental Medicine, Auf'm Hennekamp 50, 40225, Duesseldorf, Germany
| | - Ulrike Hübenthal
- IUF - Leibniz Research Institute for Environmental Medicine, Auf'm Hennekamp 50, 40225, Duesseldorf, Germany
| | - Farina Bendt
- IUF - Leibniz Research Institute for Environmental Medicine, Auf'm Hennekamp 50, 40225, Duesseldorf, Germany
| | - Jenny Baumann
- IUF - Leibniz Research Institute for Environmental Medicine, Auf'm Hennekamp 50, 40225, Duesseldorf, Germany
| | - Ellen Fritsche
- IUF - Leibniz Research Institute for Environmental Medicine, Auf'm Hennekamp 50, 40225, Duesseldorf, Germany; Heinrich-Heine University, Universitätsstr. 1, 40225, Düsseldorf, Germany.
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13
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Potential facet for prenatal arsenic exposure paradigm: linking endocrine disruption and epigenetics. THE NUCLEUS 2019. [DOI: 10.1007/s13237-019-00274-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
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14
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Winterbottom EF, Moroishi Y, Halchenko Y, Armstrong DA, Beach PJ, Nguyen QP, Capobianco AJ, Ayad NG, Marsit CJ, Li Z, Karagas MR, Robbins DJ. Prenatal arsenic exposure alters the placental expression of multiple epigenetic regulators in a sex-dependent manner. Environ Health 2019; 18:18. [PMID: 30819207 PMCID: PMC6396530 DOI: 10.1186/s12940-019-0455-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Accepted: 02/22/2019] [Indexed: 05/06/2023]
Abstract
BACKGROUND Prenatal exposure to arsenic has been linked to a range of adverse health conditions in later life. Such fetal origins of disease are frequently the result of environmental effects on the epigenome, leading to long-term alterations in gene expression. Several studies have demonstrated effects of prenatal arsenic exposure on DNA methylation; however the impact of arsenic on the generation and decoding of post-translational histone modifications (PTHMs) is less well characterized, and has not been studied in the context of prenatal human exposures. METHODS In the current study, we examined the effect of exposure to low-to-moderate levels of arsenic in a US birth cohort, on the expression of 138 genes encoding key epigenetic regulators in the fetal portion of the placenta. Our candidate genes included readers, writers and erasers of PTHMs, and chromatin remodelers. RESULTS Arsenic exposure was associated with the expression of 27 of the 138 epigenetic genes analyzed. When the cohort was stratified by fetal sex, arsenic exposure was associated with the expression of 40 genes in male fetal placenta, and only 3 non-overlapping genes in female fetal placenta. In particular, we identified an inverse relationship between arsenic exposure and expression of the gene encoding the histone methyltransferase, PRDM6 (p < 0.001). Mutation of PRDM6 has been linked to the congenital heart defect, patent ductus arteriosus. CONCLUSIONS Our findings suggest that prenatal arsenic exposure may have sex-specific effects on the fetal epigenome, which could plausibly contribute to its subsequent health impacts.
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Affiliation(s)
- Emily F. Winterbottom
- Molecular Oncology Program, DeWitt Daughtry Family Department of Surgery, University of Miami Miller School of Medicine, Miami, FL 33136 USA
| | - Yuka Moroishi
- Department of Epidemiology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755 USA
| | - Yuliya Halchenko
- Department of Epidemiology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755 USA
| | - David A. Armstrong
- Pulmonary and Critical Care Medicine, Dartmouth-Hitchcock Medical Center, Lebanon, NH 03756 USA
| | - Paul J. Beach
- Department of Epidemiology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755 USA
| | - Quang P. Nguyen
- Department of Epidemiology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755 USA
| | - Anthony J. Capobianco
- Molecular Oncology Program, DeWitt Daughtry Family Department of Surgery, University of Miami Miller School of Medicine, Miami, FL 33136 USA
| | - Nagi G. Ayad
- Center for Therapeutic Innovation, Department of Psychiatry and Behavioral Sciences, The Miami Project to Cure Paralysis, Sylvester Comprehensive Cancer Center, University of Miami, Miller School of Medicine, Miami, FL 33136 USA
| | - Carmen J. Marsit
- Department of Environmental Health, Rollins School of Public Health at Emory University, Atlanta, GA 30322 USA
| | - Zhigang Li
- Department of Epidemiology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755 USA
| | - Margaret R. Karagas
- Department of Epidemiology, Geisel School of Medicine at Dartmouth, Hanover, NH 03755 USA
| | - David J. Robbins
- Molecular Oncology Program, DeWitt Daughtry Family Department of Surgery, University of Miami Miller School of Medicine, Miami, FL 33136 USA
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Ruszkiewicz JA, Miranda-Vizuete A, Tinkov AA, Skalnaya MG, Skalny AV, Tsatsakis A, Aschner M. Sex-Specific Differences in Redox Homeostasis in Brain Norm and Disease. J Mol Neurosci 2019; 67:312-342. [DOI: 10.1007/s12031-018-1241-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Accepted: 12/10/2018] [Indexed: 12/12/2022]
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Chandravanshi LP, Gupta R, Shukla RK. Developmental Neurotoxicity of Arsenic: Involvement of Oxidative Stress and Mitochondrial Functions. Biol Trace Elem Res 2018; 186:185-198. [PMID: 29502250 DOI: 10.1007/s12011-018-1286-1] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Accepted: 02/23/2018] [Indexed: 12/31/2022]
Abstract
Over the last decade, there has been an increased concern about the health risks from exposure to arsenic at low doses, because of their neurotoxic effects on the developing brain. The exact mechanism underlying arsenic-induced neurotoxicity during sensitive periods of brain development remains unclear, although enhanced oxidative stresses, leading to mitochondrial dysfunctions might be involved. Here, we highlight the generation of reactive oxygen species (ROS) and oxidative stress which leads to mitochondrial dysfunctions and apoptosis in arsenic-induced developmental neurotoxicity. Here, the administration of sodium arsenite at doses of 2 or 4 mg/kg body weight in female rats from gestational to lactational (GD6-PD21) resulted to increased ROS, led to oxidative stress, and increased the apoptosis in the frontal cortex, hippocampus, and corpus striatum of developing rats on PD22, compared to controls. Enhanced levels of ROS were associated with decreased mitochondrial membrane potential and the activity of mitochondrial complexes, and hampered antioxidant levels. Further, neuronal apoptosis, as measured by changes in the expression of pro-apoptotic (Bax, Caspase-3), anti-apoptotic (Bcl2), and stress marker proteins (p-p38, pJNK) in arsenic-exposed rats, was discussed. The severities of changes were found to more persist in the corpus striatum than in other brain regions of arsenic-exposed rats even after the withdrawal of exposure on PD45 as compared to controls. Therefore, our results indicate that perinatal arsenic exposure leads to abrupt changes in ROS, oxidative stress, and mitochondrial functions and that apoptotic factor in different brain regions of rats might contribute to this arsenic-induced developmental neurotoxicity.
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Affiliation(s)
- Lalit P Chandravanshi
- Department of Zoology, Institute of Science, Banaras Hindu University, Varanasi, 221005, India.
- Developmental Toxicology Division, CSIR-Indian Institute of Toxicology Research, Post Box No. 80, MG Marg, Lucknow, 226 001, India.
| | - Richa Gupta
- Developmental Toxicology Division, CSIR-Indian Institute of Toxicology Research, Post Box No. 80, MG Marg, Lucknow, 226 001, India
| | - Rajendra K Shukla
- Department of Biochemistry, All India Institute of Medical Sciences, Bhopal, India
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17
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Manthari RK, Tikka C, Ommati MM, Niu R, Sun Z, Wang J, Zhang J, Wang J. Arsenic induces autophagy in developmental mouse cerebral cortex and hippocampus by inhibiting PI3K/Akt/mTOR signaling pathway: involvement of blood-brain barrier's tight junction proteins. Arch Toxicol 2018; 92:3255-3275. [PMID: 30225639 DOI: 10.1007/s00204-018-2304-y] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Accepted: 09/13/2018] [Indexed: 12/19/2022]
Abstract
For the past decade, there has been an increased concern about the health risks from arsenic (As) exposure, because of its neurotoxic effects on the developing brain. The exact mechanism underlying As-induced neurotoxicity during sensitive periods of brain development remains unclear, especially the role of blood-brain barrier's (BBB) tight junction (TJ) proteins during As-induced neurotoxicity. Here, we highlight the involvement of TJ proteins in As-induced autophagy in cerebral cortex and hippocampus during developmental periods [postnatal day (PND) 21, 28, 35 and 42]. Here, the administration of arsenic trioxide (As2O3) at doses of 0.15 mg or 1.5 mg or 15 mg As2O3/L in drinking water from gestational to lactational and continued to the pups till PND42 resulted in a significant decrease in the mRNA expression levels of TJ proteins (Occludin, Claudin, ZO-1 and ZO-2) and Occludin protein expression level. In addition, As exposure significantly decreased PI3K, Akt, mTOR, and p62 with a concomitant increase in Beclin1, LC3I, LC3II, Atg5 and Atg12. Moreover, As exposure also significantly downregulated the protein expression levels of mTOR with a concomitant upregulation of Beclin 1, LC3 and Atg12 in all the developmental age points. However, no significant alterations were observed in low and medium dose-exposed groups of PND42. Histopathological analysis in As-exposed mice revealed decreased number of pyramidal neurons in hippocampus; and neurons with degenerating axons, shrinkage of cells, remarkable vacuolar degeneration in cytoplasm, karyolysis and pyknosis in cerebral cortex. Ultrastructural analysis by transmission electron microscopy revealed the occurrence of autophagosomes and vacuolated axons in the cerebral cortex and hippocampus of the mice exposed to high dose As at PND21 and 42. The severities of changes were found to more persist in the cerebral cortex than in the hippocampus of As-exposed mice. Finally, we conclude that the leaky BBB in cerebral cortex and hippocampus may facilitate the transfer of As and induces autophagy by inhibiting PI3K/Akt/mTOR signaling pathway in an age-dependent manner, i.e., among the four different developmental age points, PND21 animals were found to be more vulnerable to the As-induced neurotoxicity than the other three age points.
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Affiliation(s)
- Ram Kumar Manthari
- Shanxi Key Laboratory of Ecological Animal Science and Environmental Veterinary Medicine, College of Animal Science and Veterinary Medicine, Shanxi Agricultural University, Taigu, Shanxi, 030801, China
| | - Chiranjeevi Tikka
- Shanxi Key Laboratory of Ecological Animal Science and Environmental Veterinary Medicine, College of Animal Science and Veterinary Medicine, Shanxi Agricultural University, Taigu, Shanxi, 030801, China
| | - Mohammad Mehdi Ommati
- Shanxi Key Laboratory of Ecological Animal Science and Environmental Veterinary Medicine, College of Animal Science and Veterinary Medicine, Shanxi Agricultural University, Taigu, Shanxi, 030801, China.,Department of Animal Science, College of Agriculture, Shiraz University, Shiraz, 71441-65186, Iran
| | - Ruiyan Niu
- Shanxi Key Laboratory of Ecological Animal Science and Environmental Veterinary Medicine, College of Animal Science and Veterinary Medicine, Shanxi Agricultural University, Taigu, Shanxi, 030801, China
| | - Zilong Sun
- Shanxi Key Laboratory of Ecological Animal Science and Environmental Veterinary Medicine, College of Animal Science and Veterinary Medicine, Shanxi Agricultural University, Taigu, Shanxi, 030801, China
| | - Jinming Wang
- Shanxi Key Laboratory of Ecological Animal Science and Environmental Veterinary Medicine, College of Animal Science and Veterinary Medicine, Shanxi Agricultural University, Taigu, Shanxi, 030801, China
| | - Jianhai Zhang
- Shanxi Key Laboratory of Ecological Animal Science and Environmental Veterinary Medicine, College of Animal Science and Veterinary Medicine, Shanxi Agricultural University, Taigu, Shanxi, 030801, China
| | - Jundong Wang
- Shanxi Key Laboratory of Ecological Animal Science and Environmental Veterinary Medicine, College of Animal Science and Veterinary Medicine, Shanxi Agricultural University, Taigu, Shanxi, 030801, China.
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Tyler CRS, Smoake JJW, Solomon ER, Villicana E, Caldwell KK, Allan AM. Sex-Dependent Effects of the Histone Deacetylase Inhibitor, Sodium Valproate, on Reversal Learning After Developmental Arsenic Exposure. Front Genet 2018; 9:200. [PMID: 29963072 PMCID: PMC6013562 DOI: 10.3389/fgene.2018.00200] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Accepted: 05/22/2018] [Indexed: 01/18/2023] Open
Abstract
Several studies have demonstrated that exposure to arsenic in drinking water adversely affects brain development and cognitive function in adulthood. While the mechanism by which arsenic induces adverse neurological outcomes remains elusive, studies suggest a link between reduced levels of histone acetylation and impaired performance on a variety of behavioral tasks following arsenic exposure. Using our developmental arsenic exposure (DAE) paradigm, we have previously reported reduced histone acetylation and associated histone acetyltransferase enzyme expression in the frontal cortex of C57BL/6J adult male mice, with no changes observed in the female frontal cortex. In the present study, we sought to determine if DAE produced sex-dependent deficits in frontal cortical executive function using the Y-maze acquisition and reversal learning tasks, which are specific for assessing cognitive flexibility. Further, we tested whether the administration of valproic acid, a class I-IIa histone deacetylase inhibitor, was able to mitigate behavioral and biochemical changes resulting from DAE. As anticipated, DAE inhibited acquisition and reversal learning performance in adult male, but not female, mice. Valproate treatment for 2 weeks restored reversal performance in the male arsenic-exposed offspring, while not affecting female performance. Protein levels of HDACs 1, 2, and 5 were elevated following behavioral assessment but only in DAE male mice; restoration of appropriate HDAC levels occurred after valproate treatment and was concurrent with improved behavioral performance, particularly during reversal learning. Female frontal cortical levels of HDAC enzymes were not impacted by DAE or valproate treatment. Finally, mRNA expression levels of brain-derived neurotrophic factor, Bdnf, which has been implicated in the control of frontal cortical flexibility and is regulated by HDAC5, were elevated in DAE male mice and restored to normal levels following HDACi treatment. Levels of mRNA encoding glutamate receptor ionotropic NMDA type subunits, which have been linked to cognitive flexibility, were not related to the reversal learning deficit in the DAE mice and were not altered by HDACi treatments. These findings demonstrate that DAE alters frontal cortical HDAC levels and Bdnf expression in males, but not females, and that these molecular changes are associated with sex-dependent differences in cognitive flexibility in a reversal-learning task.
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Affiliation(s)
| | - Jane J W Smoake
- Department of Neurosciences, University of New Mexico Health Sciences Center, Albuquerque, NM, United States
| | - Elizabeth R Solomon
- Department of Neurosciences, University of New Mexico Health Sciences Center, Albuquerque, NM, United States
| | - Estrella Villicana
- Department of Neurosciences, University of New Mexico Health Sciences Center, Albuquerque, NM, United States
| | - Kevin K Caldwell
- Department of Neurosciences, University of New Mexico Health Sciences Center, Albuquerque, NM, United States
| | - Andrea M Allan
- Department of Neurosciences, University of New Mexico Health Sciences Center, Albuquerque, NM, United States
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19
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Raciti M, Ceccatelli S. Epigenetic mechanisms in developmental neurotoxicity. Neurotoxicol Teratol 2018; 66:94-101. [DOI: 10.1016/j.ntt.2017.12.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Revised: 11/28/2017] [Accepted: 12/04/2017] [Indexed: 12/28/2022]
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20
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Murko M, Elek B, Styblo M, Thomas DJ, Francesconi KA. Dose and Diet - Sources of Arsenic Intake in Mouse in Utero Exposure Scenarios. Chem Res Toxicol 2018; 31:156-164. [PMID: 29244955 PMCID: PMC6611170 DOI: 10.1021/acs.chemrestox.7b00309] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
In humans, early life exposure to inorganic arsenic is associated with adverse health effects. Inorganic arsenic in utero or in early postnatal life also produces adverse health effects in offspring of pregnant mice that consumed drinking water containing low part per billion levels of inorganic arsenic. Because aggregate exposure of pregnant mice to inorganic arsenic from both drinking water and food has not been fully evaluated in experimental studies, quantifying arsenic exposure of the developing mouse is problematic. Here, we determined levels of total arsenic and arsenic species in natural ingredient rodent diets that are composed of many plant and animal-derived foodstuffs and in a purified ingredient rodent diet that is composed of a more restricted mixture of foodstuffs. In natural ingredient diets, total arsenic levels ranged from ∼60 to ∼400 parts per billion, and in the purified ingredient diet, total arsenic level was 13 parts per billion. Inorganic arsenic was the predominant arsenic species in trifluoroacetic acid extracts of each diet. Various exposure scenarios were evaluated using information on inorganic arsenic levels in diet and drinking water and on daily food and water consumption of pregnant mice. In a scenario in which pregnant mice consumed drinking water with 10 parts per billion of inorganic arsenic and a natural ingredient diet containing 89 parts per billion of inorganic arsenic, drinking water contributed only ∼20% of inorganic arsenic intake. Quantitation of arsenic species in diets used in studies in which drinking water is the nominal source of arsenic exposure provides more accurate dosimetry and improves understanding of dose-response relations. Use of purified ingredient diets will minimize the discrepancy between the target dosage level and the actual dosage level attained in utero exposure studies designed to evaluate effects of low level exposure to inorganic arsenic.
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Affiliation(s)
- Manuela Murko
- Institute of Chemistry, NAWI Graz, University of Graz, 8010 Graz, Austria
| | - Brittany Elek
- Pharmacokinetics Branch, Integrated Systems Toxicology Division, National Health and Environmental Effects Laboratory, Office of Research and Development, United States Environmental Protection Agency, Research Triangle Park, North Carolina 27709, United States
| | - Miroslav Styblo
- Department of Nutrition, Gillings School of Global Public Health, The University of North Carolina, Chapel Hill, North Carolina 27719, United States
| | - David J. Thomas
- Pharmacokinetics Branch, Integrated Systems Toxicology Division, National Health and Environmental Effects Laboratory, Office of Research and Development, United States Environmental Protection Agency, Research Triangle Park, North Carolina 27709, United States
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21
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Caldwell KK, Hafez A, Solomon E, Cunningham M, Allan AM. Arsenic exposure during embryonic development alters the expression of the long noncoding RNA growth arrest specific-5 (Gas5) in a sex-dependent manner. Neurotoxicol Teratol 2017; 66:102-112. [PMID: 29132937 DOI: 10.1016/j.ntt.2017.11.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Revised: 11/09/2017] [Accepted: 11/09/2017] [Indexed: 12/21/2022]
Abstract
Our previous studies suggest that prenatal arsenic exposure (50ppb) modifies epigenetic control of the programming of the glucocorticoid receptor (GR) signaling system in the developing mouse brain. These deficits may lead to long-lasting consequences, including deficits in learning and memory, increased depressive-like behaviors, and an altered set-point of GR feedback throughout life. To understand the arsenic-induced changes within the GR system, we assessed the impact of in utero arsenic exposure on the levels of the GR and growth arrest-specific-5 (Gas5), a noncoding RNA, across a key gestational period for GR programming (gestational days, GD 14-18) in mice. Gas5 contains a glucocorticoid response element (GRE)-like sequence that binds the GR, thereby decreasing GR-GRE-dependent gene transcription and potentially altering GR programming. Prenatal arsenic exposure resulted in sex-dependent and age-dependent shifts in the levels of GR and Gas5 expression in fetal telencephalon. Nuclear GR levels were reduced in males, but unchanged in females, at all gestational time points tested. Total cellular Gas5 levels were lower in arsenic-exposed males with no changes seen in arsenic-exposed females at GD16 and 18. An increase in total cellular Gas-5 along with increased nuclear levels in GD14 arsenic-exposed females, suggests a differential regulation of cellular compartmentalization of Gas5. RIP assays revealed reduced Gas5 associated with the GR on GD14 in the nuclear fraction prepared from arsenic-exposed males and females. This decrease in levels of GR-Gas5 binding continued only in the females at GD18. Thus, nuclear GR signaling potential is decreased in prenatal arsenic-exposed males, while it is increased or maintained at levels approaching normal in prenatal arsenic-exposed females. These findings suggest that females, but not males, exposed to arsenic are able to regulate the levels of nuclear free GR by altering Gas5 levels, thereby keeping GR nuclear signaling closer to control (unexposed) levels.
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Affiliation(s)
- Kevin K Caldwell
- Department of Neurosciences, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, United States
| | - Alexander Hafez
- Department of Neurosciences, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, United States
| | - Elizabeth Solomon
- Department of Neurosciences, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, United States
| | - Matthew Cunningham
- Department of Neurosciences, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, United States
| | - Andrea M Allan
- Department of Neurosciences, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, United States.
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22
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Appleton AA, Jackson BP, Karagas M, Marsit CJ. Prenatal exposure to neurotoxic metals is associated with increased placental glucocorticoid receptor DNA methylation. Epigenetics 2017; 12:607-615. [PMID: 28548590 DOI: 10.1080/15592294.2017.1320637] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
Abstract
Epigenetic alterations related to prenatal neurotoxic metals exposure may be key in understanding the origins of cognitive and neurobehavioral problems in children. Placental glucocorticoid receptor (NR3C1) methylation has been linked to neurobehavioral risk in early life, but has not been examined in response to neurotoxic metals exposure despite parallel lines of research showing metals exposure and NR3C1 methylation each contribute to a similar set of neurobehavioral phenotypes. Thus, we conducted a study of prenatal neurotoxic metals exposure and placental NR3C1 methylation in a cohort of healthy term singleton pregnancies from Rhode Island, USA (n = 222). Concentrations of arsenic (As; median 0.02 ug/g), cadmium (Cd; median 0.03 μg/g), lead (Pb; median 0.40 μg/g), manganese (Mn; median 0.56 μg/g), mercury (Hg; median 0.02 μg/g), and zinc (Zn; 145.18 μg/g) measured in infant toenails were categorized as tertiles. Multivariable linear regression models tested the independent associations for each metal with NR3C1 methylation, as well as the cumulative risk of exposure to multiple metals simultaneously. Compared to the lowest exposure tertiles, higher levels of As, Cd, Pb, Mn, and Hg were each associated with increased placental NR3C1 methylation (all P<0.02). Coefficients for these associations corresponded with a 0.71-1.41 percent increase in NR3C1 methylation per tertile increase in metals concentrations. For Zn, the lowest exposure tertile compared with the highest tertile was associated with 1.26 percent increase in NR3C1 methylation (P=0.01). Higher cumulative metal risk scores were marginally associated with greater NR3C1 methylation. Taken together, these results indicate that prenatal exposure to neurotoxic metals may affect the offspring's NR3C1 activity, which may help explain cognitive and neurodevelopmental risk later in life.
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Affiliation(s)
- Allison A Appleton
- a Department of Epidemiology and Biostatistics , University at Albany School of Public Health , Rensselaer , NY , USA
| | - Brian P Jackson
- b Department of Earth Sciences, Dartmouth College , Hanover , NH , USA
| | - Margaret Karagas
- c Department of Epidemiology , Geisel School of Medicine at Dartmouth , One Medical Center Drive, Lebanon , NH , USA
| | - Carmen J Marsit
- d Department of Environmental Health, Rollins School of Public Health , Emory University , Atlanta , GA , USA
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Tyler CR, Labrecque MT, Solomon ER, Guo X, Allan AM. Prenatal arsenic exposure alters REST/NRSF and microRNA regulators of embryonic neural stem cell fate in a sex-dependent manner. Neurotoxicol Teratol 2016; 59:1-15. [PMID: 27751817 DOI: 10.1016/j.ntt.2016.10.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Revised: 08/30/2016] [Accepted: 10/13/2016] [Indexed: 11/29/2022]
Abstract
Exposure to arsenic, a common environmental toxin found in drinking water, leads to a host of neurological pathologies. We have previously demonstrated that developmental exposure to a low level of arsenic (50ppb) alters epigenetic processes that underlie deficits in adult hippocampal neurogenesis leading to aberrant behavior. It is unclear if arsenic impacts the programming and regulation of embryonic neurogenesis during development when exposure occurs. The master negative regulator of neural-lineage, REST/NRSF, controls the precise timing of fate specification and differentiation of neural stem cells (NSCs). Early in development (embryonic day 14), we observed increased expression of Rest, its co-repressor, CoREST, and the inhibitory RNA binding/splicing protein, Ptbp1, and altered expression of mRNA spliced isoforms of Pbx1 that are directly regulated by these factors in the male brain in response to prenatal 50ppb arsenic exposure. These increases were concurrent with decreased expression of microRNA-9 (miR-9), miR-9*, and miR-124, all of which are REST/NRSF targets and inversely regulate Rest expression to allow for maturation of NSCs. Exposure to arsenic decreased the formation of neuroblasts in vitro from NSCs derived from male pup brains. The female response to arsenic was limited to increased expression of CoREST and Ptbp2, an RNA binding protein that allows for appropriate splicing of genes involved in the progression of neurogenesis. These changes were accompanied by increased neuroblast formation in vitro from NSCs derived from female pups. Unexposed male mice express transcriptomic factors to induce differentiation earlier in development compared to unexposed females. Thus, arsenic exposure likely delays differentiation of NSCs in males while potentially inducing precocious differentiation in females early in development. These effects are mitigated by embryonic day 18 of development. Arsenic-induced dysregulation of the regulatory loop formed by REST/NRSF, its target microRNAs, miR-9 and miR-124, and RNA splicing proteins, PTBP1 and 2, leads to aberrant programming of NSC function that is perhaps perpetuated into adulthood inducing deficits in differentiation we have previously observed.
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Affiliation(s)
- Christina R Tyler
- Department of Pharmaceutical Sciences, College of Pharmacy, University of New Mexico, Albuquerque, NM 87131, United States
| | - Matthew T Labrecque
- Department of Neurosciences, School of Medicine, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, United States
| | - Elizabeth R Solomon
- Department of Neurosciences, School of Medicine, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, United States
| | - Xun Guo
- Department of Neurosciences, School of Medicine, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, United States
| | - Andrea M Allan
- Department of Neurosciences, School of Medicine, University of New Mexico Health Sciences Center, Albuquerque, NM 87131, United States.
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Sex bias in paediatric autoimmune disease – Not just about sex hormones? J Autoimmun 2016; 69:12-23. [DOI: 10.1016/j.jaut.2016.02.011] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Revised: 02/25/2016] [Accepted: 02/29/2016] [Indexed: 02/06/2023]
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