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Bjørklund G, Tippairote T, Hangan T, Chirumbolo S, Peana M. Early-Life Lead Exposure: Risks and Neurotoxic Consequences. Curr Med Chem 2024; 31:1620-1633. [PMID: 37031386 DOI: 10.2174/0929867330666230409135310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2022] [Revised: 02/10/2023] [Accepted: 02/16/2023] [Indexed: 04/10/2023]
Abstract
BACKGROUND Lead (Pb) does not have any biological function in a human, and it is likely no safe level of Pb in the human body. The Pb exposure impacts are a global concern for their potential neurotoxic consequences. Despite decreasing both the environmental Pb levels and the average blood Pb levels in the survey populations, the lifetime redistribution from the tissues-stored Pb still poses neurotoxic risks from the low-level exposure in later life. The growing fetus and children hold their innate high-susceptible to these Pb-induced neurodevelopmental and neurobehavioral effects. OBJECTIVE This article aims to evaluate cumulative studies and insights on the topic of Pb neurotoxicology while assessing the emerging trends in the field. RESULTS The Pb-induced neurochemical and neuro-immunological mechanisms are likely responsible for the high-level Pb exposure with the neurodevelopmental and neurobehavioral impacts at the initial stages. Early-life Pb exposure can still produce neurodegenerative consequences in later life due to the altered epigenetic imprints and the ongoing endogenous Pb exposure. Several mechanisms contribute to the Pb-induced neurotoxic impacts, including the direct neurochemical effects, the induction of oxidative stress and inflammation through immunologic activations, and epigenetic alterations. Furthermore, the individual nutritional status, such as macro-, micro-, or antioxidant nutrients, can significantly influence the neurotoxic impacts even at low-level exposure to Pb. CONCLUSION The prevention of early-life Pb exposure is, therefore, the critical determinant for alleviating various Pb-induced neurotoxic impacts across the different age groups.
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Affiliation(s)
- Geir Bjørklund
- Council for Nutritional and Environmental Medicine (CONEM), Toften 24, Mo i Rana, 8610, Norway
| | - Torsak Tippairote
- Department of Nutritional and Environmental Medicine, HP Medical Center, Bangkok 10540, Thailand
| | - Tony Hangan
- Faculty of Medicine, Ovidius University of Constanta, Constanta, 900470, Romania
| | - Salvatore Chirumbolo
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, 37134, Italy
- CONEM Scientific Secretary, Strada Le Grazie 9, 37134, Verona, Italy
| | - Massimiliano Peana
- Department of Chemical, Physical, Mathematical and Natural Sciences, University of Sassari, Via Vienna 2, Sassari, 07100, Italy
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Choi J, Kim YS, Kim MH, Kim HJ, Yoon BE. Maternal lead exposure induces sex-dependent cerebellar glial alterations and repetitive behaviors. Front Cell Neurosci 2022; 16:954807. [PMID: 36072563 PMCID: PMC9442054 DOI: 10.3389/fncel.2022.954807] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Accepted: 07/19/2022] [Indexed: 12/04/2022] Open
Abstract
Lead (Pb) is one of the most prevalent heavy metals we encounter daily. Although there are many reports regarding their toxic effects on humans, the effects of exposure to low lead concentrations throughout the pregnancy period on the offspring are not fully elucidated yet. This study aimed to investigate the cellular mechanisms that occur in response to lead exposure. To this end, we administered lead-containing water to pregnant mice from the day of conception till delivery or till day 28 postnatally. Furthermore, we performed neurodevelopmental disorder-related behavior tests and RNA-sequencing analysis. We used both genders for all experiments because neurodevelopmental disorders usually show several sex-dependent differences. The results revealed increased levels of gliosis in the cerebella of lead-exposed pups compared to those in littermates belonging to the control group. Additionally, we observed altered behaviors of male mice in the autism spectrum disorder-related tests. RNA-sequencing results revealed changes in gamma-aminobutyric acid (GABA) signaling in the lead-exposed mouse model. Specifically, the lead-exposed male mice showed decreased monoamine oxidase B and increased levels of diamine oxidase enzyme, which is related to the synthesis of GABA in astrocytes. These findings demonstrate sex-dependent basal developmental changes in glial cells and an increased prevalence of autistic-like behaviors in the young pups of mothers exposed to lead during pregnancy.
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Affiliation(s)
- Juwon Choi
- Department of Molecular Biology, College of Natural Sciences, Dankook University, Cheonan, South Korea
| | - Yoo Sung Kim
- Department of Molecular Biology, College of Natural Sciences, Dankook University, Cheonan, South Korea
| | - Mi-Hye Kim
- Department of Physiology, College of Medicine, Dankook University, Cheonan, South Korea
- Department of Medical Laser, Graduate School, Dankook University, Cheonan, South Korea
| | - Hee Jung Kim
- Department of Physiology, College of Medicine, Dankook University, Cheonan, South Korea
| | - Bo-Eun Yoon
- Department of Molecular Biology, College of Natural Sciences, Dankook University, Cheonan, South Korea
- *Correspondence: Bo-Eun Yoon,
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3
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Altered genome-wide hippocampal gene expression profiles following early life lead exposure and their potential for reversal by environmental enrichment. Sci Rep 2022; 12:11937. [PMID: 35879375 PMCID: PMC9314447 DOI: 10.1038/s41598-022-15861-9] [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: 08/05/2021] [Accepted: 06/30/2022] [Indexed: 12/02/2022] Open
Abstract
Early life lead (Pb) exposure is detrimental to neurobehavioral development. The quality of the environment can modify negative influences from Pb exposure, impacting the developmental trajectory following Pb exposure. Little is known about the molecular underpinnings in the brain of the interaction between Pb and the quality of the environment. We examined relationships between early life Pb exposure and living in an enriched versus a non-enriched postnatal environment on genome-wide transcription profiles in hippocampus CA1. RNA-seq identified differences in the transcriptome of enriched vs. non-enriched Pb-exposed animals. Most of the gene expression changes associated with Pb exposure were reversed by enrichment. This was also true for changes in upstream regulators, splicing events and long noncoding RNAs. Non-enriched rats also had memory impairments; enriched rats had no deficits. The results demonstrate that an enriched environment has a profound impact on behavior and the Pb-modified CA1 transcriptome. These findings show the potential for interactions between Pb exposure and the environment to result in significant transcriptional changes in the brain and, to the extent that this may occur in Pb-exposed children, could influence neuropsychological/educational outcomes, underscoring the importance for early intervention and environmental enrichment for Pb-exposed children.
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Gómez-Arnaiz S, Tate RJ, Grant MH. Cobalt Neurotoxicity: Transcriptional Effect of Elevated Cobalt Blood Levels in the Rodent Brain. TOXICS 2022; 10:toxics10020059. [PMID: 35202246 PMCID: PMC8878729 DOI: 10.3390/toxics10020059] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 01/12/2022] [Accepted: 01/13/2022] [Indexed: 12/11/2022]
Abstract
Metal-on-metal (MoM) hip implants made of cobalt chromium (CoCr) alloy have shown early failure compared with other bearing materials. A consequence of the abnormal wear produced by these prostheses is elevated levels of cobalt in the blood of patients, which can lead to systemic conditions involving cardiac and neurological symptoms. In order to better understand the implications for patients with these implants, we carried out metal content and RNA-Seq analysis of excised tissue from rats treated intraperitonially for 28 days with low concentrations of cobalt. Cobalt blood levels in dosed rats were found to be similar to those seen in some patients with MoM implants (range: 4–38 μg/L Co in blood). Significant accumulation of cobalt was measured in a range of tissues including kidney, liver, and heart, but also in brain tissue. RNA-Seq analysis of neural tissue revealed that exposure to cobalt induces a transcriptional response in the prefrontal cortex (pref. cortex), cerebellum, and hippocampus. Many of the most up- and downregulated genes appear to correspond to choroid plexus transcripts. These results indicate that the choroid plexus could be the brain tissue most affected by cobalt. More specifically, the differentially expressed genes show a disruption of steroidogenesis and lipid metabolism. Several other transcripts also demonstrate that cobalt induces an immune response. In summary, cobalt exposure induces alterations in the brain transcriptome, more specifically, the choroid plexus, which is in direct contact with neurotoxicants at the blood–cerebrospinal fluid barrier.
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Affiliation(s)
- Sara Gómez-Arnaiz
- Wolfson Centre, Biomedical Engineering Department, University of Strathclyde, Glasgow G4 0NW, UK;
| | - Rothwelle J. Tate
- Strathclyde Institute for Pharmacy & Biomedical Sciences, University of Strathclyde, 161 Cathedral Street, Glasgow G4 0RE, UK;
| | - Mary Helen Grant
- Wolfson Centre, Biomedical Engineering Department, University of Strathclyde, Glasgow G4 0NW, UK;
- Correspondence:
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Meyer DN, Crofts EJ, Akemann C, Gurdziel K, Farr R, Baker BB, Weber D, Baker TR. Developmental exposure to Pb 2+ induces transgenerational changes to zebrafish brain transcriptome. CHEMOSPHERE 2020; 244:125527. [PMID: 31816550 PMCID: PMC7015790 DOI: 10.1016/j.chemosphere.2019.125527] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 11/27/2019] [Accepted: 11/30/2019] [Indexed: 05/24/2023]
Abstract
Lead (Pb2+) is a major public health hazard for urban children, with profound and well-characterized developmental and behavioral implications across the lifespan. The ability of early Pb2+ exposure to induce epigenetic changes is well-established, suggesting that Pb2+-induced neurobehavioral deficits may be heritable across generations. Understanding the long-term and multigenerational repercussions of lead exposure is crucial for clarifying both the genotypic alterations behind these behavioral outcomes and the potential mechanism of heritability. To study this, zebrafish (Danio rerio) embryos (<2 h post fertilization; EK strain) were exposed for 24 h to waterborne Pb2+ at a concentration of 10 μM. This exposed F0 generation was raised to adulthood and spawned to produce the F1 generation, which was subsequently spawned to produce the F2 generation. Previous avoidance conditioning studies determined that a 10 μM Pb2+ dose resulted in learning impairments persisting through the F2 generation. RNA was extracted from control- and 10 μM Pb2+-lineage F2 brains, (n = 10 for each group), sequenced, and transcript expression was quantified utilizing Quant-Seq. 648 genes were differentially expressed in the brains of F2 lead-lineage fish versus F2 control-lineage fish. Pathway analysis revealed altered genes in processes including synaptic function and plasticity, neurogenesis, endocrine homeostasis, and epigenetic modification, all of which are implicated in lead-induced neurobehavioral deficits and/or their inheritance. These data will inform future investigations to elucidate the mechanism of adult-onset and transgenerational health effects of developmental lead exposure.
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Affiliation(s)
- Danielle N Meyer
- Department of Pharmacology, School of Medicine, Wayne State University, Detroit, MI, USA; Institute of Environmental Health Sciences, School of Medicine, Wayne State University, Detroit, MI, USA
| | - Emily J Crofts
- Institute of Environmental Health Sciences, School of Medicine, Wayne State University, Detroit, MI, USA
| | - Camille Akemann
- Department of Pharmacology, School of Medicine, Wayne State University, Detroit, MI, USA; Institute of Environmental Health Sciences, School of Medicine, Wayne State University, Detroit, MI, USA
| | - Katherine Gurdziel
- Applied Genome Technology Center, School of Medicine, Wayne State University, Detroit, MI, USA
| | - Rebecca Farr
- Department of Pharmacology, School of Medicine, Wayne State University, Detroit, MI, USA
| | - Bridget B Baker
- Institute of Environmental Health Sciences, School of Medicine, Wayne State University, Detroit, MI, USA; Division of Laboratory Animal Resources, School of Medicine, Wayne State University, Detroit, MI, USA
| | - Daniel Weber
- Children's Environmental Health Sciences Core Center, University of Wisconsin-Milwaukee, Milwaukee, WI, USA
| | - Tracie R Baker
- Department of Pharmacology, School of Medicine, Wayne State University, Detroit, MI, USA; Institute of Environmental Health Sciences, School of Medicine, Wayne State University, Detroit, MI, USA.
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Onuzulu CD, Rotimi OA, Rotimi SO. Epigenetic modifications associated with in utero exposure to endocrine disrupting chemicals BPA, DDT and Pb. REVIEWS ON ENVIRONMENTAL HEALTH 2019; 34:309-325. [PMID: 31271561 DOI: 10.1515/reveh-2018-0059] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Accepted: 04/03/2019] [Indexed: 06/09/2023]
Abstract
Endocrine disrupting chemicals (EDCs) are xenobiotics which adversely modify the hormone system. The endocrine system is most vulnerable to assaults by endocrine disruptors during the prenatal and early development window, and effects may persist into adulthood and across generations. The prenatal stage is a period of vulnerability to environmental chemicals because the epigenome is usually reprogrammed during this period. Bisphenol A (BPA), lead (Pb), and dichlorodiphenyltrichloroethane (DDT) were chosen for critical review because they have become serious public health concerns globally, especially in Africa where they are widely used without any regulation. In this review, we introduce EDCs and describe the various modes of action of EDCs and the importance of the prenatal and developmental windows to EDC exposure. We give a brief overview of epigenetics and describe the various epigenetic mechanisms: DNA methylation, histone modifications and non-coding RNAs, and how each of them affects gene expression. We then summarize findings from previous studies on the effects of prenatal exposure to the endocrine disruptors BPA, Pb and DDT on each of the previously described epigenetic mechanisms. We also discuss how the epigenetic alterations caused by these EDCs may be related to disease processes.
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Affiliation(s)
- Chinonye Doris Onuzulu
- Department of Biochemistry and Molecular Biology Research Laboratory, Covenant University, Ota, Ogun State, Nigeria
| | - Oluwakemi Anuoluwapo Rotimi
- Department of Biochemistry and Molecular Biology Research Laboratory, Covenant University, Ota, Ogun State, Nigeria
| | - Solomon Oladapo Rotimi
- Department of Biochemistry and Molecular Biology Research Laboratory, Covenant University, Ota, Ogun State, Nigeria
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Khalid M, Abdollahi M. Epigenetic modifications associated with pathophysiological effects of lead exposure. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART C, ENVIRONMENTAL CARCINOGENESIS & ECOTOXICOLOGY REVIEWS 2019; 37:235-287. [PMID: 31402779 DOI: 10.1080/10590501.2019.1640581] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Lead (Pb) exposure during different stages of development has demonstrated dose, duration, sex, and tissue-specific pathophysiological outcomes due to altered epigenetic regulation via (a) DNA methylation, (b) histone modifications, (c) miRNAs, and (d) chromatin accessibility. Pb-induced alteration of epigenetic regulation causes neurotoxic and extra-neurotoxic pathophysiological outcomes. Neurotoxic effects of Pb include dysfunction of memory and learning, behavioral disorder, attention deficit hyperactivity disorder, autism spectrum disorder, aging, Alzheimer's disease, tauopathy, and neurodegeneration. Extra-neurotoxic effects of Pb include altered body weight, metabolic disorder, cardiovascular disorders, hematopoietic disorder, and reproductive impairment. Pb exposure either early in life or at any stage of development results in undesirable pathophysiological outcomes that tends to sustain and maintain for a lifetime.
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Affiliation(s)
- Madiha Khalid
- Toxicology and Diseases Group, Pharmaceutical Sciences Research Center (PSRC), The Institute of Pharmaceutical Sciences (TIPS), Tehran University of Medical Sciences (TUMS), Tehran, Iran
| | - Mohammad Abdollahi
- Toxicology and Diseases Group, Pharmaceutical Sciences Research Center (PSRC), The Institute of Pharmaceutical Sciences (TIPS), Tehran University of Medical Sciences (TUMS), Tehran, Iran
- Department of Toxicology and Pharmacology, Faculty of Pharmacy, Tehran University of Medical Sciences, Tehran, Iran
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Tena A, Peru E, Martinetti LE, Cano JC, Loyola Baltazar CD, Wagler AE, Skouta R, Fenelon K. Long-term consequences of early postnatal lead exposure on hippocampal synaptic activity in adult mice. Brain Behav 2019; 9:e01307. [PMID: 31268249 PMCID: PMC6710227 DOI: 10.1002/brb3.1307] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Revised: 03/15/2019] [Accepted: 03/29/2019] [Indexed: 11/29/2022] Open
Abstract
INTRODUCTION Lead (Pb) exposure yielding blood lead levels (BLL) as low as 2 µg/dl in children is an international problem. More common in US low-income neighborhoods, childhood Pb exposure can cause behavioral and cognitive deficits, including working memory impairments, which can persist into adulthood. So far, studies characterized short-term effects of high Pb exposure on neuronal structure and function. However, long-term consequences of early chronic Pb exposure on neuronal activity are poorly documented. METHODS Here, we exposed male and female mice (PND [postnatal day] 0 to PND 28) to one of three Pb treatments: 0 ppm (sodium-treated water, control), 30 ppm (low dose), and 330 ppm (high dose) lead acetate. Once the male and female mice were 9-12 months old, extracellular field recordings on hippocampal slices were performed. RESULTS We show that at CA3 to CA1 synapses, synaptic transmission was decreased and neuronal fiber activity was increased in males exposed to lowest level Pb. In contrast, both synaptic transmission and neuronal fiber activity were increased in females exposed to high Pb. The ventral hippocampus-medial prefrontal cortex (vHPC-mPFC) synapses are crucial for working memory in rodents. The lowest level Pb decreased vHPC-mPFC synaptic transmission, whereas high Pb decreased short-term synaptic depression. CONCLUSIONS Overall, we show for the first time that early exposure to either high or lowest level Pb has long-term consequences on different synaptic properties of at least two hippocampal synapses. Such consequences of early Pb exposure might worsen the cognitive decline observed in aging men and women. Our results suggest that additional efforts should focus on the consequences of early Pb exposure especially in at-risk communities.
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Affiliation(s)
- Anahis Tena
- Department of Biological Sciences, College of ScienceUniversity of Texas at El PasoEl PasoTexas
| | - Eduardo Peru
- Department of Biological Sciences, College of ScienceUniversity of Texas at El PasoEl PasoTexas
| | - Luis E. Martinetti
- Department of Biological Sciences, College of ScienceUniversity of Texas at El PasoEl PasoTexas
| | - Jose C. Cano
- Department of Biological Sciences, College of ScienceUniversity of Texas at El PasoEl PasoTexas
| | | | - Amy E. Wagler
- Department of Mathematical Sciences, College of ScienceUniversity of Texas at El PasoEl PasoTexas
| | - Rachid Skouta
- Department of Chemistry, College of Natural ScienceUniversity of Massachusetts AmherstAmherstMassachusetts
| | - Karine Fenelon
- Department of Biological Sciences, College of ScienceUniversity of Texas at El PasoEl PasoTexas
- Biology Department, College of Natural ScienceUniversity of Massachusetts AmherstAmherstMassachusetts
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Lunde‐Young R, Ramirez J, Naik V, Orzabal M, Lee J, Konganti K, Hillhouse A, Threadgill D, Ramadoss J. Hippocampal transcriptome reveals novel targets of FASD pathogenesis. Brain Behav 2019; 9:e01334. [PMID: 31140755 PMCID: PMC6625466 DOI: 10.1002/brb3.1334] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Revised: 05/01/2019] [Accepted: 05/06/2019] [Indexed: 01/26/2023] Open
Abstract
INTRODUCTION Prenatal alcohol exposure can contribute to fetal alcohol spectrum disorders (FASD), characterized by a myriad of developmental impairments affecting behavior and cognition. Studies show that many of these functional impairments are associated with the hippocampus, a structure exhibiting exquisite vulnerability to developmental alcohol exposure and critically implicated in learning and memory; however, mechanisms underlying alcohol-induced hippocampal deficits remain poorly understood. By utilizing a high-throughput RNA-sequencing (RNA-seq) approach to address the neurobiological and molecular basis of prenatal alcohol-induced hippocampal functional deficits, we hypothesized that chronic binge prenatal alcohol exposure alters gene expression and global molecular pathways in the fetal hippocampus. METHODS Timed-pregnant Sprague-Dawley rats were randomly assigned to a pair-fed control (PF) or binge alcohol (ALC) treatment group on gestational day (GD) 4. ALC dams acclimatized from GDs 5-10 with a daily treatment of 4.5 g/kg alcohol and subsequently received 6 g/kg on GDs 11-20. PF dams received a once daily maltose dextrin gavage on GDs 5-20, isocalorically matching ALC counterparts. On GD 21, bilateral hippocampi were dissected, flash frozen, and stored at -80° C. Total RNA was then isolated from homogenized tissues. Samples were normalized to ~4nM and pooled equally. Sequencing was performed by Illumina NextSeq 500 on a 75 cycle, single-end sequencing run. RESULTS RNA-seq identified 13,388 genes, of these, 76 genes showed a significant difference (p < 0.05, log2 fold change ≥2) in expression between the PF and ALC groups. Forty-nine genes showed sex-dependent dysregulation; IPA analysis showed among female offspring, dysregulated pathways included proline and citrulline biosynthesis, whereas in males, xenobiotic metabolism signaling and alaninine biosynthesis etc. were altered. CONCLUSION We conclude that chronic binge alcohol exposure during pregnancy dysregulates fetal hippocampal gene expression in a sex-specific manner. Identification of subtle, transcriptome-level dysregulation in hippocampal molecular pathways offers potential mechanistic insights underlying FASD pathogenesis.
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Affiliation(s)
- Raine Lunde‐Young
- Department of Veterinary Physiology and Pharmacology, College of Veterinary Medicine and Biomedical SciencesTexas A&M UniversityCollege StationTexas
| | - Josue Ramirez
- Department of Veterinary Physiology and Pharmacology, College of Veterinary Medicine and Biomedical SciencesTexas A&M UniversityCollege StationTexas
| | - Vishal Naik
- Department of Veterinary Physiology and Pharmacology, College of Veterinary Medicine and Biomedical SciencesTexas A&M UniversityCollege StationTexas
| | - Marcus Orzabal
- Department of Veterinary Physiology and Pharmacology, College of Veterinary Medicine and Biomedical SciencesTexas A&M UniversityCollege StationTexas
| | - Jehoon Lee
- Department of Veterinary Physiology and Pharmacology, College of Veterinary Medicine and Biomedical SciencesTexas A&M UniversityCollege StationTexas
| | - Kranti Konganti
- Department of Veterinary Pathobiology, College of Veterinary Medicine and Biomedical SciencesTexas A&M UniversityCollege StationTexas
| | - Andrew Hillhouse
- Department of Veterinary Pathobiology, College of Veterinary Medicine and Biomedical SciencesTexas A&M UniversityCollege StationTexas
| | - David Threadgill
- Department of Veterinary Pathobiology, College of Veterinary Medicine and Biomedical SciencesTexas A&M UniversityCollege StationTexas
| | - Jayanth Ramadoss
- Department of Veterinary Physiology and Pharmacology, College of Veterinary Medicine and Biomedical SciencesTexas A&M UniversityCollege StationTexas
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Azam S, Miksovska J. Pb 2+ Binds to Downstream Regulatory Element Antagonist Modulator (DREAM) and Modulates Its Interactions with Binding Partners: A Link between Neuronal Calcium Sensors and Pb 2+ Neurotoxicity. ACS Chem Neurosci 2019; 10:1263-1272. [PMID: 30399317 DOI: 10.1021/acschemneuro.8b00335] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Pb2+ exposure leads to diverse neurological disorders; however, the mechanism of Pb2+-induced neurotoxicity is not clearly understood. Here we demonstrate that Pb2+ binds to EF-hands in apo-DREAM (downstream regulatory element antagonist modulator) with a lower equilibrium dissociation constant ( Kd = 20 ± 2 nM) than Ca2+ ( Kd = 1 μM). Based on the Trp169 emission and CD spectra, we report that Pb2+ association triggers changes in the protein secondary and tertiary structures that are analogous to those previously observed for Ca2+-bound protein. The hydrophobic cavity in the C-terminal domain of DREAM is solvent exposed in the presence of Pb2+ as determined using a hydrophobic probe, 1-anilinonaphthalene-8-sulfonic acid (1,8-ANS). Pb2+ association with DREAM also modulates interactions between DREAM and its intracellular partners as evident from the fact that Pb2+-bound DREAM associates with peptide-based model systems, presenilin-1 helix-9 "PS1HL9" KV4.3(70-90) "site-2" and KV4.3(2-22) "site 1". Namely, dissociation constants for Pb2+-bound DREAM interaction with PS1HL9 ( Kd = 2.4 ± 0.1 μM), site-2 ( Kd = 11.0 ± 0.5 μM) and site 1 ( Kd = 5.0 ± 0.6 μM) are nearly identical to those observed for Ca2+ bound DREAM. Isothermal titration calorimetry data reveal that Pb2+ binds to two high-affinity sites in Ca2+ bound DREAM with the overall apparent constant of 4.81 ± 0.06 μM and its binding to Ca2+ bound DREAM is entropy-driven. Taking into account the structural and sequence similarity between DREAM and other neuronal calcium sensor (NCS) proteins, these results strongly indicate that DREAM and possibly other NCS proteins bind Pb2+ with a higher affinity than that for Ca2+ and Pb2+ interactions with NCS proteins can contribute to Pb2+-induced neurotoxicity.
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Affiliation(s)
- Samiol Azam
- Department of Chemistry and Biochemistry, Florida International University, Miami, Florida 33199, United States
| | - Jaroslava Miksovska
- Department of Chemistry and Biochemistry, Florida International University, Miami, Florida 33199, United States
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Meitzen J, Britson KA, Tuomela K, Mermelstein PG. The expression of select genes necessary for membrane-associated estrogen receptor signaling differ by sex in adult rat hippocampus. Steroids 2019; 142:21-27. [PMID: 28962849 PMCID: PMC5874170 DOI: 10.1016/j.steroids.2017.09.012] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Revised: 09/14/2017] [Accepted: 09/22/2017] [Indexed: 12/21/2022]
Abstract
17β-estradiol can rapidly modulate neuron function via membrane estrogen receptors (ERs) in a sex-specific manner. For example, female rat hippocampal neurons express palmitoylated versions of ERα and ERβ that associate with the plasma membrane. These membrane-associated ERs are organized by caveolin proteins into functional signaling microdomains with metabotropic glutamate receptors (mGluRs). ER/mGluR signaling mediates several sex-specific estradiol actions on hippocampal neuron function. An important unanswered question regards the mechanism by which sex-specific membrane-associated ER signaling is generated, especially since it has been previously demonstrated that mGluR action is not sex-specific. One possibility is that the genes necessary for the ER membrane complex are differentially expressed between males and females, including genes that encode ERα and β, caveolin 1 and 3, and/or the palmitoylacyltransferases DHHC-7 and -21. Thus we used qPCR to test the hypothesis that these genes show sex differences in expression in neonatal and adult rat hippocampus. As an additional control we tested the expression of the 20 other DHHC palmitoylacyltransferases with no known connections to ER. In neonatal hippocampus, no sex differences were detected in gene expression. In adult hippocampus, the genes that encode caveolin 1 and DHHC-7 showed decreased expression in females compared to males. Thus, select genes differ by sex at specific developmental stages, arguing for a more nuanced model than simple widespread perinatal emergence of sex differences in all genes enabling sex-specific estradiol action. These findings enable the generation of new hypotheses regarding the mechanisms by which sex differences in membrane-associated ER signaling are programmed.
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Affiliation(s)
- John Meitzen
- Dept. of Biological Sciences, North Carolina State University, Raleigh, NC, United States; W.M. Keck Center for Behavioral Biology, North Carolina State University, Raleigh, NC, United States; Center for Human Health and the Environment, North Carolina State University, Raleigh, NC, United States; Comparative Medicine Institute, North Carolina State University, Raleigh, NC, United States.
| | - Kyla A Britson
- Cellular and Molecular Medicine Graduate Program, Johns Hopkins School of Medicine, Baltimore, MD, United States
| | - Krista Tuomela
- Medical College of Wisconsin, Milwaukee, WI, United States
| | - Paul G Mermelstein
- Dept. of Neuroscience, University of Minnesota, Minneapolis, MN, United States
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12
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Neuwirth LS, Phillips GR, El Idrissi A. Perinatal Pb 2+ exposure alters the expression of genes related to the neurodevelopmental GABA-shift in postnatal rats. J Biomed Sci 2018; 25:45. [PMID: 29793500 PMCID: PMC5967126 DOI: 10.1186/s12929-018-0450-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2018] [Accepted: 05/18/2018] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Lead (Pb2+) is an environmental neurotoxicant that disrupts neurodevelopment, communication, and organization through competition with Ca2+ signaling. How perinatal Pb2+ exposure affects Ca2+-related gene regulation remains unclear. However, Ca2+ activates the L-Type voltage sensitive calcium channel β-3 subunit (Ca-β3), which autoregulates neuronal excitability and plays a role in the GABA-shift from excitatory-to-inhibitory neurotransmission. METHOD A total of eight females (n = 4 Control and n = 4 Perinatal) and four males (n = 2 Control and n = 2 Perinatal) rats were used as breeders to serve as Dams and Sires. The Dam's litters each ranged from N = 6-10 pups per litter (M = 8, SD = 2), irrespective of Pb2+ treatment, with a majority of males over females. Since there were more males in each of the litters than females, to best assess and equally control for Pb2+- and litter-effects across all developmental time-points under study, female pups were excluded due to an insufficient sample size availability from the litter's obtained. From the included pup litters, 24 experimentally naïve male Long Evans hooded rat pups (Control N = 12; Pb2+ N = 12) were used in the present study. Brains were extracted from rat prefrontal cortex (PFC) and hippocampus (HP) at postnatal day (PND) 2, 7, 14 and 22, were homogenized in 1 mL of TRIzol reagent per 100 mg of tissue using a glass-Teflon homogenizer. Post-centrifugation, RNA was extracted with chloroform and precipitated with isopropyl alcohol. RNA samples were then re-suspended in 100 μL of DEPC treated H2O. Next, 10 μg of total RNA was treated with RNase-free DNase (Qiagen) at 37 °C for 1 h and re-purified by a 3:1 phenol/chloroform extraction followed by an ethanol precipitation. From the purified RNA, 1 μg was used in the SYBR GreenER Two-Step qRT-PCR kit (Invitrogen) for first strand cDNA synthesis and the quantitative real-time PCR (qRT-PCR). The effects of perinatal Pb2+ exposure on genes related to early neuronal development and the GABA-shift were evaluated through the expression of: Ca-β3, GABAAR-β3, NKCC1, KCC2, and GAD 80, 86, 65, and 67 isoforms. RESULTS Perinatal Pb2+ exposure significantly altered the GABA-shift neurodevelopmental GOI expression as a function of Pb2+ exposure and age across postnatal development. Dramatic changes were observed with Ca-β3 expression consistent with a Pb2+ competition with L-type calcium channels. By PND 22, Ca-β3 mRNA was reduced by 1-fold and 1.5-fold in PFC and HP respectively, relative to controls. All HP GABA-β3 mRNA levels were particularly vulnerable to Pb2+ at PND 2 and 7, and both PFC and HP were negatively impacted by Pb2+ at PND 22. Additionally, Pb2+ altered both the PFC and HP immature GAD 80/86 mRNA expression particularly at PND 2, whereas mature GAD 65/67 were most significantly affected by Pb2+ at PND 22. CONCLUSIONS Perinatal Pb2+ exposure disrupts the expression of mRNAs related to the GABA-shift, potentially altering the establishment, organization, and excitability of neural circuits across development. These findings offer new insights into the altered effects Pb2+ has on the GABAergic system preceding what is known regarding Pb2+ insults unto the glutamatergic system.
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Affiliation(s)
- Lorenz S. Neuwirth
- Department of Psychology, SUNY Old Westbury, 223 Store Hill Road, Bldg.: NAB, Room: 2059, Old Westbury, NY 11568-1700 USA
- SUNY Old Westbury, Neuroscience Research Institute, 223 Store Hill Road, Bldg.: NAB, Room: 2059, Old Westbury, NY 11568-1700 USA
- Department of Biology, The College of Staten Island (CUNY), Staten Island, NY 10314 USA
- The CUNY Graduate Center, Biology Program, New York, NY 10016 USA
- The Center for Developmental Neuroscience, Staten Island, NY 10314 USA
| | - Greg R. Phillips
- Department of Biology, The College of Staten Island (CUNY), Staten Island, NY 10314 USA
- The CUNY Graduate Center, Biology Program, New York, NY 10016 USA
- The Center for Developmental Neuroscience, Staten Island, NY 10314 USA
| | - Abdeslem El Idrissi
- Department of Biology, The College of Staten Island (CUNY), Staten Island, NY 10314 USA
- The CUNY Graduate Center, Biology Program, New York, NY 10016 USA
- The Center for Developmental Neuroscience, Staten Island, NY 10314 USA
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13
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Singh G, Singh V, Sobolewski M, Cory-Slechta DA, Schneider JS. Sex-Dependent Effects of Developmental Lead Exposure on the Brain. Front Genet 2018; 9:89. [PMID: 29662502 PMCID: PMC5890196 DOI: 10.3389/fgene.2018.00089] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Accepted: 03/02/2018] [Indexed: 11/23/2022] Open
Abstract
The role of sex as an effect modifier of developmental lead (Pb) exposure has until recently received little attention. Lead exposure in early life can affect brain development with persisting influences on cognitive and behavioral functioning, as well as, elevated risks for developing a variety of diseases and disorders in later life. Although both sexes are affected by Pb exposure, the incidence, manifestation, and severity of outcomes appears to differ in males and females. Results from epidemiologic and animal studies indicate significant effect modification by sex, however, the results are not consistent across studies. Unfortunately, only a limited number of human epidemiological studies have included both sexes in independent outcome analyses limiting our ability to draw definitive conclusions regarding sex-differentiated outcomes. Additionally, due to various methodological differences across studies, there is still not a good mechanistic understanding of the molecular effects of lead on the brain and the factors that influence differential responses to Pb based on sex. In this review, focused on prenatal and postnatal Pb exposures in humans and animal models, we discuss current literature supporting sex differences in outcomes in response to Pb exposure and explore some of the ideas regarding potential molecular mechanisms that may contribute to sex-related differences in outcomes from developmental Pb exposure. The sex-dependent variability in outcomes from developmental Pb exposure may arise from a combination of complex factors, including, but not limited to, intrinsic sex-specific molecular/genetic mechanisms and external risk factors including sex-specific responses to environmental stressors which may act through shared epigenetic pathways to influence the genome and behavioral output.
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Affiliation(s)
- Garima Singh
- Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA, United States
| | - Vikrant Singh
- Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA, United States
| | - Marissa Sobolewski
- Department of Environmental Medicine, University of Rochester Medical Center, Rochester, NY, United States
| | - Deborah A Cory-Slechta
- Department of Environmental Medicine, University of Rochester Medical Center, Rochester, NY, United States
| | - Jay S Schneider
- Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA, United States
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14
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Sex-specific effects of developmental lead exposure on the immune-neuroendocrine network. Toxicol Appl Pharmacol 2017; 334:142-157. [DOI: 10.1016/j.taap.2017.09.009] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Revised: 08/28/2017] [Accepted: 09/09/2017] [Indexed: 01/22/2023]
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15
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Xue WZ, Gu X, Wu Y, Li D, Xu Y, Wang HL. Multiple regulatory aspects of histone methyltransferase EZH2 in Pb-induced neurotoxicity. Oncotarget 2017; 8:85169-85184. [PMID: 29156711 PMCID: PMC5689601 DOI: 10.18632/oncotarget.19615] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2016] [Accepted: 07/06/2017] [Indexed: 12/02/2022] Open
Abstract
Pb is a pervasive environmental threat to human health. Although remarkable progress has been made in its neurotoxicity, the precise molecular mechanisms underlying this widespread toxicant still remain elusive. In this study, the detailed roles of EZH2, a transcriptional repressor, in the regulation of Pb-led neurotoxicity were investigated, highlighting its sub-functionalization, compartmentalization, functional chaperones and downstream partners. Based on the findings, EZH2’s protein levels were significantly reduced in response to Pb treatment; EZH2’s gain-of-function trials recovered the dampened neurite outgrowth; EZH2’ recruitment to ploycomb complex, as well as its interaction with cytosolic Vav1, was altered in a distinct manner, suggesting that EZH2’s multiple roles were markedly redistributed in this context; EZH2’s cytosolic and nuclear presence differed in their respective response towards Pb treatment; EZH2 directly occupied the promoters of EGR2, NGFR and CaMKK2, genes responsible for various nerve functions and repair mechanisms, and essentially contributed to their aberrant expression. It indicated that EZH2 mediated the dynamic changes of a cascade of key molecules and consequently the related neurological impairments. In summary, EZH2 emerges as a central player to regulate Pb-led neurotoxicity in a transcriptionally dependent and independent manner, and thereby provided a promising molecular target for medical intervention.
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Affiliation(s)
- Wei-Zhen Xue
- School of Food Science and Engineering, Hefei University of Technology, Hefei, Anhui 230009, PR China
| | - Xiaozhen Gu
- School of Food Science and Engineering, Hefei University of Technology, Hefei, Anhui 230009, PR China
| | - Yulan Wu
- School of Food Science and Engineering, Hefei University of Technology, Hefei, Anhui 230009, PR China
| | - Danyang Li
- School of Food Science and Engineering, Hefei University of Technology, Hefei, Anhui 230009, PR China
| | - Yi Xu
- School of Food Science and Engineering, Hefei University of Technology, Hefei, Anhui 230009, PR China
| | - Hui-Li Wang
- School of Food Science and Engineering, Hefei University of Technology, Hefei, Anhui 230009, PR China
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16
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Verma M, Schneider JS. Strain specific effects of low level lead exposure on associative learning and memory in rats. Neurotoxicology 2017; 62:186-191. [PMID: 28720388 DOI: 10.1016/j.neuro.2017.07.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 07/01/2017] [Accepted: 07/12/2017] [Indexed: 12/28/2022]
Abstract
Exposure to lead (Pb) remains a significant public health concern. Lead exposure in early life impairs the normal development of numerous cognitive and neurobehavioral processes. Previous work has shown that the effects of developmental Pb exposure on gene expression patterns in the brain are modulated by various factors including the developmental timing of the exposure, level of exposure, sex, and genetic background. Using gene microarray profiling, we previously reported a significant strain-specific effect of Pb exposure on the hippocampal transcriptome, with the greatest number of differentially expressed transcripts in Long Evans (LE) rats and the fewest in Sprague Dawley (SD) rats. The present study examined the extent to which this differential effect of Pb on hippocampal gene expression might influence behavior. Animals (males and females) were tested in a trace fear conditioning paradigm to evaluate effects of Pb exposures (perinatal (PERI; gestation to postnatal day 21) or early postnatal (EPN; postnatal day 1 to day 21)) on associative learning and memory. All animals (Pb-exposed and non-Pb-exposed controls) showed normal acquisition of the conditioned stimulus (tone)-unconditioned stimulus (footshock) association. Long Evans rats showed a significant deficit in short- and long-term recall, influenced by sex and the timing of Pb exposure (PERI or EPN). In contrast, Pb exposure had no significant effect on memory consolidation or recall in any SD rats. These results further demonstrate the important influence of genetic background to the functional outcomes from developmental Pb exposure.
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Affiliation(s)
- Megha Verma
- Department of Pathology, Anatomy Cell Biology, Thomas Jefferson University, Philadelphia, PA, 19107, United States.
| | - J S Schneider
- Department of Pathology, Anatomy Cell Biology, Thomas Jefferson University, Philadelphia, PA, 19107, United States
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17
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Vázquez Bahéna AB, Talavera Mendoza O, Moreno Godínez ME, Salgado Souto SA, Ruiz J, Huerta Beristain G. Source apportionment of lead in the blood of women of reproductive age living near tailings in Taxco, Guerrero, Mexico: An isotopic study. THE SCIENCE OF THE TOTAL ENVIRONMENT 2017; 583:104-114. [PMID: 28108093 DOI: 10.1016/j.scitotenv.2017.01.030] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Revised: 12/22/2016] [Accepted: 01/05/2017] [Indexed: 06/06/2023]
Abstract
The concentration and isotopic composition of lead in the blood of forty seven women of reproductive age (15-45y) exposed to multiple sources in two rural communities of the mining region of Taxco, Guerrero in southern Mexico were determined in order to identify specific contributing sources and their apportionment and to trace probable ingestion pathways. Our data indicate that >36% of the studied women have blood lead concentrations above 10μgdL-1 and up to 87% above 5μgdL-1. Tailings contain between 2128 and 5988mgkg-1 of lead and represent the most conspicuous source in the area. Lead contents in indoor dust are largely variable (21.7-987mgkg-1) but only 15% of samples are above the Mexican Regulatory Guideline for urban soils (400mgkg-1). By contrast, 85% of glazed containers (range: 0.026-68.6mgkg-1) used for cooking and food storage are above the maximum 2mgL-1 of soluble lead established in the Mexican Guideline. The isotopic composition indicates that lead in the blood of 95% of the studied women can be modeled in terms of a mixing system between local ores (and derivatives), glazed pottery and Morelos bedrock, end-members, with the two former being largely the most important contributors. Only one sample shows influence of indoor paints. Indoor dust is dominated by ores and derivatives but some samples show evidence of contribution from a less radiogenic source very likely represented by interior paints. This study supports the application of lead isotopic ratios to identify potential sources and their apportionment in humans exposed to multiple sources of lead from both, natural and anthropogenic origin.
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Affiliation(s)
- Analine Berenice Vázquez Bahéna
- UA Ciencias Químico Biológicas, Universidad Autónoma de Guerrero, Av. Lázaro Cárdenas s/n. Ciudad Universitaria, Chilpancingo, Guerrero C.P. 39090, Mexico
| | - Oscar Talavera Mendoza
- UA Ciencias Químico Biológicas, Universidad Autónoma de Guerrero, Av. Lázaro Cárdenas s/n. Ciudad Universitaria, Chilpancingo, Guerrero C.P. 39090, Mexico; UA de Ciencias de la Tierra, Universidad Autónoma de Guerrero, Exhacienda S. Juan Bautista, Taxco el Viejo, Guerrero C.P. 40323, Mexico.
| | - Ma Elena Moreno Godínez
- UA Ciencias Químico Biológicas, Universidad Autónoma de Guerrero, Av. Lázaro Cárdenas s/n. Ciudad Universitaria, Chilpancingo, Guerrero C.P. 39090, Mexico
| | - Sergio Adrián Salgado Souto
- UA de Ciencias de la Tierra, Universidad Autónoma de Guerrero, Exhacienda S. Juan Bautista, Taxco el Viejo, Guerrero C.P. 40323, Mexico
| | - Joaquín Ruiz
- Department of Geosciences, The University of Arizona, 1040 E. 4th St. Gould-Simpson Building #77, Tucson, AZ 85721, United States
| | - Gerardo Huerta Beristain
- UA Ciencias Químico Biológicas, Universidad Autónoma de Guerrero, Av. Lázaro Cárdenas s/n. Ciudad Universitaria, Chilpancingo, Guerrero C.P. 39090, Mexico
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18
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Chung BYT, Bignell W, Jacklin DL, Winters BD, Bailey CDC. Postsynaptic nicotinic acetylcholine receptors facilitate excitation of developing CA1 pyramidal neurons. J Neurophysiol 2016; 116:2043-2055. [PMID: 27489367 DOI: 10.1152/jn.00370.2016] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Accepted: 08/01/2016] [Indexed: 11/22/2022] Open
Abstract
The hippocampus plays a key role in learning and memory. The normal development and mature function of hippocampal networks supporting these cognitive functions depends on afferent cholinergic neurotransmission mediated by nicotinic acetylcholine receptors. Whereas it is well-established that nicotinic receptors are present on GABAergic interneurons and on glutamatergic presynaptic terminals within the hippocampus, the ability of these receptors to mediate postsynaptic signaling in pyramidal neurons is not well understood. We use whole cell electrophysiology to show that heteromeric nicotinic receptors mediate direct inward currents, depolarization from rest and enhanced excitability in hippocampus CA1 pyramidal neurons of male mice. Measurements made throughout postnatal development provide a thorough developmental profile for these heteromeric nicotinic responses, which are greatest during the first 2 wk of postnatal life and decrease to low adult levels shortly thereafter. Pharmacological experiments show that responses are blocked by a competitive antagonist of α4β2* nicotinic receptors and augmented by a positive allosteric modulator of α5 subunit-containing receptors, which is consistent with expression studies suggesting the presence of α4β2 and α4β2α5 nicotinic receptors within the developing CA1 pyramidal cell layer. These findings demonstrate that functional heteromeric nicotinic receptors are present on CA1 pyramidal neurons during a period of major hippocampal development, placing these receptors in a prime position to play an important role in the establishment of hippocampal cognitive networks.
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Affiliation(s)
- Beryl Y T Chung
- Department of Biomedical Sciences, Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada; and
| | - Warren Bignell
- Department of Biomedical Sciences, Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada; and
| | - Derek L Jacklin
- Department of Psychology, College of Social and Applied Human Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Boyer D Winters
- Department of Psychology, College of Social and Applied Human Sciences, University of Guelph, Guelph, Ontario, Canada
| | - Craig D C Bailey
- Department of Biomedical Sciences, Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada; and
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19
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Research directives toward deciphering adverse outcome pathways induced by environmental metallotoxins. Curr Opin Chem Eng 2016. [DOI: 10.1016/j.coche.2016.09.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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20
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Anderson DW, Mettil W, Schneider JS. Effects of low level lead exposure on associative learning and memory in the rat: Influences of sex and developmental timing of exposure. Toxicol Lett 2016; 246:57-64. [PMID: 26812500 DOI: 10.1016/j.toxlet.2016.01.011] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Revised: 12/23/2015] [Accepted: 01/18/2016] [Indexed: 12/20/2022]
Abstract
Lead (Pb) exposure during development impairs a variety of cognitive, behavioral and neurochemical processes resulting in deficits in learning, memory, attention, impulsivity and executive function. Numerous studies have attempted to model this effect of Pb in rodents, with the majority of studies focusing on hippocampus-associated spatial learning and memory processes. Using a different paradigm, trace fear conditioning, a process requiring coordinated integration of both the medial prefrontal cortex and the hippocampus, we have assessed the effects of Pb exposure on associative learning and memory. The present study examined both female and male long evans rats exposed to three environmentally relevant levels of Pb (150 ppm, 375 ppm and 750 ppm) during different developmental periods: perinatal (PERI; gestation-postnatal day 21), early postnatal (EPN; postnatal days 1-21) and late postnatal (LPN; postnatal days 1-55). Testing began at postnatal day 55 and consisted of a single day of acquisition training, and three post training time points (1, 2 and 10 days) to assess memory consolidation and recall. All animals, regardless of sex, developmental window or level of Pb-exposure, successfully acquired conditioned-unconditioned stimulus association during training. However, there were significant effects of Pb-exposure on consolidation and memory recall at days 1-10 post training. In females, EPN and LPN exposure to 150 ppm Pb (but not PERI exposure) significantly impaired recall. In contrast, only PERI 150 ppm and 750 ppm-exposed males had significant recall deficits. These data suggest a complex interaction between sex, developmental window of exposure and Pb-exposure level on consolidation and recall of associative memories.
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Affiliation(s)
- D W Anderson
- Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA 19107, USA.
| | - W Mettil
- Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - J S Schneider
- Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA 19107, USA
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21
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Lee J, Freeman JL. Embryonic exposure to 10 μg L−1lead results in female-specific expression changes in genes associated with nervous system development and function and Alzheimer's disease in aged adult zebrafish brain. Metallomics 2016; 8:589-96. [PMID: 26776728 DOI: 10.1039/c5mt00267b] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Embryonic exposure to Pb at levels as low as 10 μg L−1disturb global gene expression patterns in a sex-specific manner.
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Affiliation(s)
- Jinyoung Lee
- School of Health Sciences
- Purdue University
- West Lafayette, USA
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22
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Sánchez-Martín FJ, Lindquist DM, Landero-Figueroa J, Zhang X, Chen J, Cecil KM, Medvedovic M, Puga A. Sex- and tissue-specific methylome changes in brains of mice perinatally exposed to lead. Neurotoxicology 2014; 46:92-100. [PMID: 25530354 DOI: 10.1016/j.neuro.2014.12.004] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Revised: 12/09/2014] [Accepted: 12/10/2014] [Indexed: 11/29/2022]
Abstract
Changes in DNA methylation and subsequent changes in gene expression regulation are the hallmarks of age- and tissue-dependent epigenetic drift and plasticity resulting from the combinatorial integration of genetic determinants and environmental cues. To determine whether perinatal lead exposure caused persistent DNA methylation changes in target tissues, we exposed mouse dams to 0, 3 or 30 ppm of lead acetate in drinking water for a period extending from 2 months prior to mating, through gestation, until weaning of pups at postnatal day-21, and analyzed whole-genome DNA methylation in brain cortex and hippocampus of 2-month old exposed and unexposed progeny. Lead exposure resulted in hypermethylation of three differentially methylated regions in the hippocampus of females, but not males. These regions mapped to Rn4.5s, Sfi1, and Rn45s loci in mouse chromosomes 2, 11 and 17, respectively. At a conservative fdr<0.001, 1623 additional CpG sites were differentially methylated in female hippocampus, corresponding to 117 unique genes. Sixty of these genes were tested for mRNA expression and showed a trend toward negative correlation between mRNA expression and methylation in exposed females but not males. No statistically significant methylome changes were detected in male hippocampus or in cortex of either sex. We conclude that exposure to lead during embryonic life, a time when the organism is most sensitive to environmental cues, appears to have a sex- and tissue-specific effect on DNA methylation that may produce pathological or physiological deviations from the epigenetic plasticity operative in unexposed mice.
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Affiliation(s)
- Francisco Javier Sánchez-Martín
- Department of Environmental Health and Center for Environmental Genetics, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA
| | - Diana M Lindquist
- Imaging Research Center, Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Julio Landero-Figueroa
- Metallomics Center of the Americas, Department of Chemistry, University of Cincinnati, Cincinnati, OH 45219, USA
| | - Xiang Zhang
- Department of Environmental Health and Center for Environmental Genetics, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA
| | - Jing Chen
- Department of Environmental Health and Center for Environmental Genetics, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA
| | - Kim M Cecil
- Imaging Research Center, Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Mario Medvedovic
- Department of Environmental Health and Center for Environmental Genetics, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA
| | - Alvaro Puga
- Department of Environmental Health and Center for Environmental Genetics, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA
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23
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Schneider JS, Talsania K, Mettil W, Anderson DW. Genetic diversity influences the response of the brain to developmental lead exposure. Toxicol Sci 2014; 141:29-43. [PMID: 24913800 PMCID: PMC4271117 DOI: 10.1093/toxsci/kfu101] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Accepted: 05/14/2014] [Indexed: 11/14/2022] Open
Abstract
Although extrinsic factors, such as nutritional status, and some intrinsic genetic factors may modify susceptibility to developmental lead (Pb) poisoning, no studies have specifically examined the influence of genetic background on outcomes from Pb exposure. In this study, we used gene microarray profiling to identify Pb-responsive genes in rats of different genetic backgrounds, including inbred (Fischer 344 (F344)) and outbred (Long Evans (LE), Sprague Dawley (SD)) strains, to investigate the role that genetic variation may play in influencing outcomes from developmental Pb exposure. Male and female animals received either perinatal (gestation through lactation) or postnatal (birth through weaning) exposure to Pb in food (0, 250, or 750 ppm). RNA was extracted from the hippocampus at day 55 and hybridized to Affymetrix Rat Gene 1.0 ST Arrays. There were significant strain-specific effects of Pb on the hippocampal transcriptome with 978 transcripts differentially expressed in LE rats across all experimental groups, 269 transcripts differentially expressed in F344 rats, and only 179 transcripts differentially expressed in SD rats. These results were not due to strain-related differences in brain accumulation of Pb. Further, no genes were consistently differentially regulated in all experimental conditions. There was no set of "Pb toxicity" genes that are a molecular signature for Pb neurotoxicity that transcended sex, exposure condition, and strain. These results demonstrate the influence that strain and genetic background play in modifying the brain's response to developmental Pb exposure and may have relevance for better understanding the molecular underpinnings of the lack of a neurobehavioral signature in childhood Pb poisoning.
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Affiliation(s)
- Jay S Schneider
- Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107
| | - Keyur Talsania
- Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107
| | - William Mettil
- Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107
| | - David W Anderson
- Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107
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24
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Abazyan B, Dziedzic J, Hua K, Abazyan S, Yang C, Mori S, Pletnikov MV, Guilarte TR. Chronic exposure of mutant DISC1 mice to lead produces sex-dependent abnormalities consistent with schizophrenia and related mental disorders: a gene-environment interaction study. Schizophr Bull 2014; 40:575-84. [PMID: 23716713 PMCID: PMC3984515 DOI: 10.1093/schbul/sbt071] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
The glutamatergic hypothesis of schizophrenia suggests that hypoactivity of the N-methyl-D-aspartate receptor (NMDAR) is an important factor in the pathophysiology of schizophrenia and related mental disorders. The environmental neurotoxicant, lead (Pb(2+)), is a potent and selective antagonist of the NMDAR. Recent human studies have suggested an association between prenatal Pb(2+) exposure and the increased likelihood of schizophrenia later in life, possibly via interacting with genetic risk factors. In order to test this hypothesis, we examined the neurobehavioral consequences of interaction between Pb(2+) exposure and mutant disrupted in schizophrenia 1 (mDISC1), a risk factor for major psychiatric disorders. Mutant DISC1 and control mice born by the same dams were raised and maintained on a regular diet or a diet containing moderate levels of Pb(2+). Chronic, lifelong exposure of mDISC1 mice to Pb(2+) was not associated with gross developmental abnormalities but produced sex-dependent hyperactivity, exaggerated responses to the NMDAR antagonist, MK-801, mildly impaired prepulse inhibition of the acoustic startle, and enlarged lateral ventricles. Together, these findings support the hypothesis that environmental toxins could contribute to the pathogenesis of mental disease in susceptible individuals.
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Affiliation(s)
- Bagrat Abazyan
- *To whom correspondence should be addressed; Department of Environmental Health Sciences, Columbia University, Mailman School of Public Health, 722 West 168th Street, Room 1105-E, New York, NY 10032, US; tel: 212-305-3959, fax: 212-305-3857, e-mail:
| | - Jenifer Dziedzic
- Department of Environmental Health Sciences, Columbia University, Mailman School of Public Health, New York, NY
| | - Kegang Hua
- Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD;
| | - Sofya Abazyan
- Department of Psychiatry, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Chunxia Yang
- Department of Psychiatry, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Susumu Mori
- Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD;
| | - Mikhail V. Pletnikov
- Department of Psychiatry, Johns Hopkins University School of Medicine, Baltimore, MD;,Department of Molecular and Comparative Pathobiology, Johns Hopkins University School of Medicine, Baltimore, MD;,Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Tomas R. Guilarte
- Department of Environmental Health Sciences, Columbia University, Mailman School of Public Health, New York, NY;,*To whom correspondence should be addressed; Department of Environmental Health Sciences, Columbia University, Mailman School of Public Health, 722 West 168th Street, Room 1105-E, New York, NY 10032, US; tel: 212-305-3959, fax: 212-305-3857, e-mail:
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25
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Power MC, Korrick S, Tchetgen Tchetgen EJ, Nie LH, Grodstein F, Hu H, Weuve J, Schwartz J, Weisskopf MG. Lead exposure and rate of change in cognitive function in older women. ENVIRONMENTAL RESEARCH 2014; 129:69-75. [PMID: 24529005 PMCID: PMC3951744 DOI: 10.1016/j.envres.2013.12.010] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2013] [Revised: 12/19/2013] [Accepted: 12/20/2013] [Indexed: 05/16/2023]
Abstract
BACKGROUND Higher long-term cumulative lead exposure predicts faster cognitive decline in older men, but evidence of an association in women is lacking. OBJECTIVE To determine if there is an association between lead exposure and cognitive decline in women. METHODS This study considers a sample of 584 women from the Nurses' Health Study who live in or near Boston, Massachusetts. We quantified lead exposure using biomarkers of lead exposure assessed in 1993-2004 and evaluated cognitive decline by repeated performance on a telephone battery of cognitive tests primarily assessing learning, memory, executive function, and attention completed in 1995-2008. All cognitive test scores were z-transformed for use in analyses. We used linear mixed models with random effects to quantify the association between each lead biomarker and change in cognition overall and on each individual test. RESULTS Consideration of individual tests showed greater cognitive decline with increased tibia lead concentrations, a measure of long-term cumulative exposure, for story memory and category fluency. The estimated excess annual decline in overall cognitive test z-score per SD increase in tibia bone lead concentration was suggestive, although the confidence intervals included the null (0.024 standard units, 95% confidence interval: -0.053, 0.004 - an additional decline in function equivalent to being 0.33 years older). We found little support for associations between cognitive decline and patella or blood lead, which provide integrated measures of exposure over shorter timeframes. CONCLUSIONS Long-term cumulative lead exposure may be weakly associated with faster cognitive decline in community-dwelling women, at least in some cognitive domains.
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Affiliation(s)
- Melinda C Power
- Department of Epidemiology, Harvard School of Public Health, 677 Huntington Avenue, Boston, MA 02115, USA; Department of Environmental Health, Harvard School of Public Health, 677 Huntington Avenue, Boston, MA 02115, USA.
| | - Susan Korrick
- Department of Environmental Health, Harvard School of Public Health, 677 Huntington Avenue, Boston, MA 02115, USA; Channing Division of Network Medicine, Department of Medicine at Brigham and Women's Hospital and Harvard Medical School, 181 Longwood Avenue, Boston, MA 02115, USA.
| | - Eric J Tchetgen Tchetgen
- Department of Epidemiology, Harvard School of Public Health, 677 Huntington Avenue, Boston, MA 02115, USA; Department of Biostatistics, Harvard School of Public Health, 677 Huntington Avenue, Boston, MA 02115, USA.
| | - Linda H Nie
- Purdue University, School of Health Sciences, College of Health and Human Sciences, 700 W. State Street, West Lafayette, IN 47907, USA.
| | - Francine Grodstein
- Department of Epidemiology, Harvard School of Public Health, 677 Huntington Avenue, Boston, MA 02115, USA; Channing Division of Network Medicine, Department of Medicine at Brigham and Women's Hospital and Harvard Medical School, 181 Longwood Avenue, Boston, MA 02115, USA.
| | - Howard Hu
- Department of Environmental Health Sciences at the University of Michigan School of Public Health, 1415 Washington Heights, Ann Arbor, MI 48109, USA.
| | - Jennifer Weuve
- Department of Environmental Health, Harvard School of Public Health, 677 Huntington Avenue, Boston, MA 02115, USA; Institute of Healthy Aging and Department of Internal Medicine, Rush University Medical Center, 1653 W. Congress Parkway, Chicago, IL 60612, USA.
| | - Joel Schwartz
- Department of Epidemiology, Harvard School of Public Health, 677 Huntington Avenue, Boston, MA 02115, USA; Department of Environmental Health, Harvard School of Public Health, 677 Huntington Avenue, Boston, MA 02115, USA.
| | - Marc G Weisskopf
- Department of Epidemiology, Harvard School of Public Health, 677 Huntington Avenue, Boston, MA 02115, USA; Department of Environmental Health, Harvard School of Public Health, 677 Huntington Avenue, Boston, MA 02115, USA.
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26
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Senut MC, Cingolani P, Sen A, Kruger A, Shaik A, Hirsch H, Suhr ST, Ruden D. Epigenetics of early-life lead exposure and effects on brain development. Epigenomics 2013; 4:665-74. [PMID: 23244311 DOI: 10.2217/epi.12.58] [Citation(s) in RCA: 91] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The epigenetic machinery plays a pivotal role in the control of many of the body's key cellular functions. It modulates an array of pliable mechanisms that are readily and durably modified by intracellular or extracellular factors. In the fast-moving field of neuroepigenetics, it is emerging that faulty epigenetic gene regulation can have dramatic consequences on the developing CNS that can last a lifetime and perhaps even affect future generations. Mounting evidence suggests that environmental factors can impact the developing brain through these epigenetic mechanisms and this report reviews and examines the epigenetic effects of one of the most common neurotoxic pollutants of our environment, which is believed to have no safe level of exposure during human development: lead.
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Affiliation(s)
- Marie-Claude Senut
- Institute of Environmental Health Sciences, CS Mott Center for Human Health & Development & Department of Obstetrics & Gynecology, Wayne State University, Detroit, MI 48201, USA
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Influence of developmental lead exposure on expression of DNA methyltransferases and methyl cytosine-binding proteins in hippocampus. Toxicol Lett 2012; 217:75-81. [PMID: 23246732 DOI: 10.1016/j.toxlet.2012.12.004] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2012] [Revised: 12/04/2012] [Accepted: 12/05/2012] [Indexed: 02/07/2023]
Abstract
Developmental exposure to lead (Pb) has adverse effects on cognitive functioning and behavior that can persist into adulthood. Exposures that occur during fetal or early life periods may produce changes in brain related to physiological re-programming from an epigenetic influence such as altered DNA methylation status. Since DNA methylation is regulated by DNA methyltransferases and methyl cytosine-binding proteins, this study assessed the extent to which developmental Pb exposure might affect expression of these proteins in the hippocampus. Long Evans dams were fed chow with or without added Pb acetate (0, 150, 375, 750 ppm) prior to breeding and remained on the same diet through weaning (perinatal exposure group). Other animals were exposed to the same doses of Pb but exposure started on postnatal day 1 and continued through weaning (early postnatal exposure group). All animals were euthanized on day 55 and hippocampi were removed. Western blot analyses showed significant effects of Pb exposure on DNMT1, DNMT3a, and MeCP2 expression, with effects often seen at the lowest level of exposure and modified by sex and developmental window of Pb exposure. These data suggest potential epigenetic effects of developmental Pb exposure on DNA methylation mediated at least in part through dysregulation of methyltransferases.
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28
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Sex and rearing condition modify the effects of perinatal lead exposure on learning and memory. Neurotoxicology 2012; 33:985-95. [PMID: 22542453 DOI: 10.1016/j.neuro.2012.04.016] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2011] [Revised: 04/01/2012] [Accepted: 04/12/2012] [Indexed: 11/20/2022]
Abstract
Developmental lead (Pb) exposure is associated with cognitive impairments in humans and rodents alike. In particular, impaired spatial learning and memory, as assessed using the Morris water maze (MWM), has been noted in developmentally Pb-exposed rats. Although sex and rearing environment can influence MWM performance in normal animals, the interactions of sex and rearing environment on the impact of developmental Pb exposure on hippocampal-dependent processes has not been well characterized. The present study examined the effects of perinatal exposure (i.e., gestation through weaning) to different levels of Pb (250, 750 and 1500 ppm Pb acetate in food) in males and females raised in a non-enriched environment (standard cage with 3 animals and no toys) or an enriched environment (large cage containing a variety of toys that were changed twice weekly). Testing in the MWM began at postnatal day 55. Behavioral outcomes were influenced by sex and rearing environment, with complex interactions with Pb exposure. In non-Pb exposed control animals, beneficial effects of environmental enrichment on spatial learning and memory were observed in males and females, with greater effects in females. Pb exposure in females mitigated at least some of the benefits of enrichment on learning, particularly at the lowest and highest exposure levels. In males, enrichment conferred a modest learning advantage and for the most part, Pb exposure did not affect this. However, in males with the highest Pb exposure, enrichment did help to overcome detrimental effects of Pb on learning. In females, any potential benefit to reference memory contributed by enrichment was muted by exposure to Pb and for the most part, this was not reproduced in males. Thus, there are complex interactions between sex, environment, and Pb exposure on spatial learning and memory. Environmental manipulation is a potential risk modifier of developmental Pb exposure and interacts with other factors including sex and amount of Pb exposure to affect the functional influences of Pb on the brain.
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