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Guo J, Li R, Ouyang Z, Tang J, Zhang W, Chen H, Zhu Q, Zhang J, Zhu G. Insights into the mechanism of transcription factors in Pb 2+-induced apoptosis. Toxicology 2024; 503:153760. [PMID: 38387706 DOI: 10.1016/j.tox.2024.153760] [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: 10/19/2023] [Revised: 02/12/2024] [Accepted: 02/19/2024] [Indexed: 02/24/2024]
Abstract
The health risks associated with exposure to heavy metals, such as Pb2+, are increasingly concerning the public. Pb2+ can cause significant harm to the human body through oxidative stress, autophagy, inflammation, and DNA damage, disrupting cellular homeostasis and ultimately leading to cell death. Among these mechanisms, apoptosis is considered crucial. It has been confirmed that transcription factors play a central role as mediators during the apoptosis process. Interestingly, these transcription factors have different effects on apoptosis depending on the concentration and duration of Pb2+ exposure. In this article, we systematically summarize the significant roles of several transcription factors in Pb2+-induced apoptosis. This information provides insights into therapeutic strategies and prognostic biomarkers for diseases related to Pb2+ exposure.
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Affiliation(s)
- Jingchong Guo
- The First Clinical Medical College of Nanchang University, Nanchang 330006, China
| | - Ruikang Li
- The First Clinical Medical College of Nanchang University, Nanchang 330006, China
| | - Zhuqing Ouyang
- The First Clinical Medical College of Nanchang University, Nanchang 330006, China
| | - Jiawen Tang
- The First Clinical Medical College of Nanchang University, Nanchang 330006, China
| | - Wei Zhang
- Department of Anatomy, Medical College of Nanchang University, Nanchang 330006, China
| | - Hui Chen
- Department of Anatomy, Medical College of Nanchang University, Nanchang 330006, China
| | - Qian Zhu
- Department of Anatomy, Medical College of Nanchang University, Nanchang 330006, China
| | - Jing Zhang
- Department of Anatomy, Medical College of Nanchang University, Nanchang 330006, China.
| | - Gaochun Zhu
- Department of Anatomy, Medical College of Nanchang University, Nanchang 330006, China.
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2
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Masbough F, Shadnia S, Rahimi M, Roshanzamiri S, Evini PE, Mostafazadeh B. A rare case report of lead encephalopathy due to high blood lead level. Clin Case Rep 2023; 11:e7663. [PMID: 37415586 PMCID: PMC10320365 DOI: 10.1002/ccr3.7663] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2023] [Revised: 05/27/2023] [Accepted: 06/23/2023] [Indexed: 07/08/2023] Open
Abstract
Here we report a case of lead poisoning having a serum lead level of 412 mcg dL-1 who presented with decreasing level of consciousness and recurrent seizures. He responded well to treatment with chelation therapy.
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Affiliation(s)
- Farnoosh Masbough
- Department of Clinical Pharmacy, School of PharmacyShahid Beheshti University of Medical SciencesTehranIran
| | - Shahin Shadnia
- Toxicological Research Center, Excellence Center & Department of Clinical Toxicology, School of MedicineShahid Beheshti University of Medical SciencesTehranIran
| | - Mitra Rahimi
- Toxicological Research Center, Excellence Center & Department of Clinical Toxicology, School of MedicineShahid Beheshti University of Medical SciencesTehranIran
| | - Soheil Roshanzamiri
- Department of Clinical Pharmacy, School of PharmacyShahid Beheshti University of Medical SciencesTehranIran
| | - Peyman Erfantalab Evini
- Toxicological Research Center, Excellence Center & Department of Clinical Toxicology, School of MedicineShahid Beheshti University of Medical SciencesTehranIran
| | - Babak Mostafazadeh
- Toxicological Research Center, Excellence Center & Department of Clinical Toxicology, School of MedicineShahid Beheshti University of Medical SciencesTehranIran
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Stoltzfus AT, Campbell CJ, Worth MM, Hom K, Stemmler TL, Michel SLJ. Pb(II) coordination to the nonclassical zinc finger tristetraprolin: retained function with an altered fold. J Biol Inorg Chem 2023; 28:85-100. [PMID: 36478265 DOI: 10.1007/s00775-022-01980-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Accepted: 10/26/2022] [Indexed: 12/13/2022]
Abstract
Tristetraprolin (TTP) is a nonclassical CCCH zinc finger (ZF) that plays a crucial role in regulating inflammation. TTP regulates cytokine mRNAs by specific binding of its two conserved ZF domains (CysX8CysX5CysX3His) to adenylate-uridylate-rich sequences (AREs) at the 3'-untranslated region, leading to degradation of the RNA. Dysregulation of TTP in animal models has demonstrated several cytokine-related syndromes, including chronic inflammation and autoimmune disorders. Exposure to Pb(II), a prevalent environmental toxin, is known to contribute to similar pathologies, in part by disruption of and/or competition with cysteine-rich metalloproteins. TTP's role during stress as a ubiquitous translational regulator of cell signaling (and dysfunction), which may underpin various phenotypes of Pb(II) toxicity, highlights the importance of understanding the interaction between TTP and Pb(II). The impact of Pb(II) binding on TTP's fold and RNA-binding function was analyzed via UV-Vis spectroscopy, circular dichroism, X-ray absorption spectroscopy, nuclear magnetic resonance spectroscopy, and fluorescence anisotropy. A construct containing the two ZF domains of TTP (TTP-2D) bound to Pb(II) with nanomolar affinity and exhibited a different geometry and fold in comparison to Zn2-TTP-2D. Despite the altered secondary structure, Pb(II)-substituted TTP-2D bound a canonical ARE sequence more selectively than Zn2-TTP-2D. Taken together, these data suggest that Pb(II) may interfere with proper TTP regulation and hinder the cell's ability to respond to inflammation.
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Affiliation(s)
- Andrew T Stoltzfus
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, MD, 21201, USA
| | - Courtney J Campbell
- Department of Pharmaceutical Sciences, Wayne State University, Detroit, MI, 48201, USA
| | - Madison M Worth
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, MD, 21201, USA
| | - Kellie Hom
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, MD, 21201, USA
| | - Timothy L Stemmler
- Department of Pharmaceutical Sciences, Wayne State University, Detroit, MI, 48201, USA
| | - Sarah L J Michel
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, MD, 21201, USA.
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Harper E, Cunningham E, Connolly L. Using in vitro bioassays to guide the development of safer bio-based polymers for use in food packaging. FRONTIERS IN TOXICOLOGY 2022; 4:936014. [PMID: 36204697 PMCID: PMC9531239 DOI: 10.3389/ftox.2022.936014] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Accepted: 08/01/2022] [Indexed: 11/24/2022] Open
Abstract
Petroleum-based polymers traditionally used for plastic packaging production have been shown to leach dangerous chemicals such as bisphenol-A (BPA). Bio-based polymers are potentially safer alternatives, and many can be sustainably sourced from waste streams in the food industry. This study assesses bio-based polymers undergoing food packaging development for migration of endocrine disrupting leachates at the level of estrogen, androgen and progestagen nuclear receptor transcriptional activity. Reporter gene assays were coupled with migration testing, performed using standardised test conditions for storage and temperature. Test samples include nine bio-based polymers and four inorganic waste additives mixed with a traditional petroleum-based polymer, polypropylene. Thermoplastic starch material, polybutylene succinate, polycaprolactone, polybutylene adipate terephthalate (PBAT), two polylactic acid (PLA)/PBAT blends, polyhydroxybutyrate (PHB) and eggshell/polypropylene (10:90) presented no significant reduction in metabolic activity or hormonal activity under any test condition. Polypropylene (PP) presented no hormonal activity. Metabolic activity was reduced in the estrogen responsive cell line after 10 days migration testing of eggshell/polypropylene (0.1:99.9) in MeOH at 40°C, and PP in MeOH and dH20. Estrogenic agonist activity was observed after 10 days in poultry litter ash/polypropylene (10:90) in MeOH at 20°C and 40°C, poultry feather based polymer in MeOH and dH2O at 40°C, and eggshell/polypropylene (40:60) and PLA in dH2O at 40°C. Activity was within a range of 0.26–0.50 ng 17β-estradiol equivalents per ml, equating to an estrogenic potency of 3–∼2800 times less than the estrogenic leachate BPA. Poultry litter ash/polypropylene (10:90) in MeOH for 10 days presented estrogenic activity at 20°C and 40°C within the above range and anti-androgenic activity at 40°C. Progestagenic activity was not observed for any of the compounds under any test condition. Interestingly, lower concentrations of eggshell or PP may eliminate eggshell estrogenicity and PP toxicity. Alternatively eggshell may bind and eliminate the toxic elements of PP. Similarly, PLA estrogenic activity was removed in both PLA/PBAT blends. This study demonstrates the benefits of bioassay guidance in the development of safer and sustainable packaging alternatives to petroleum-based plastics. Manipulating the types of additives and their formulations alongside toxicological testing may further improve safety aspects.
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Affiliation(s)
- Emma Harper
- Institute for Global Food Security, School of Biological Sciences, Queen’s University Belfast, Belfast, United Kingdom
| | - Eoin Cunningham
- School of Mechanical and Aerospace Engineering, Queen’s University Belfast, Belfast, United Kingdom
| | - Lisa Connolly
- Institute for Global Food Security, School of Biological Sciences, Queen’s University Belfast, Belfast, United Kingdom
- *Correspondence: Lisa Connolly,
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Wani AL, Hammad Ahmad Shadab GG, Afzal M. Lead and zinc interactions - An influence of zinc over lead related toxic manifestations. J Trace Elem Med Biol 2021; 64:126702. [PMID: 33285442 DOI: 10.1016/j.jtemb.2020.126702] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 09/30/2020] [Accepted: 11/23/2020] [Indexed: 01/19/2023]
Abstract
BACKGROUND Interaction between metals is known from earlier studies, in which one metal influences the absorption and functional role of other. Lead is known to cause debilitating effects in living organisms and also prevents several essential trace metals from functioning normally. METHODS The relevant literature using the key words lead toxicity, lead zinc interaction, zinc nutrition and the ability of zinc to act against lead has been reviewed. RESULTS Role of several nutrients in reducing the manifestations of toxic metals have been elucidated recently. Lead damages bio-membranes, causes cognitive disabilities and disturbs the normal process of DNA replication and transcription. Zinc on the other hand helps in proper maintenance of the cellular membranes and plays an important role as a metal cofactor in most of the proteins vital for membrane integrity. Zinc has essential role in cognitive functioning, zinc finger proteins and significantly neutralizes most toxic effects of lead. CONCLUSION Increased lead exposure and limited resources for tackling lead poisoning may cause an increased possibility of future environmental emergencies. Interactions between essential nutrient metals and non-essential toxic metals may act as important factor which can be used to target the metal toxicities. An assumption is made that the lead toxicity can be reduced by maintaining the status of essential trace metals like zinc.
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Affiliation(s)
- Ab Latif Wani
- Cytogenetics and Molecular Toxicological Laboratory, Section of Genetics, Department of Zoology, Faculty of Life Sciences, Aligarh Muslim University, Aligarh, 202002, Uttar Pradesh, India.
| | - G G Hammad Ahmad Shadab
- Cytogenetics and Molecular Toxicological Laboratory, Section of Genetics, Department of Zoology, Faculty of Life Sciences, Aligarh Muslim University, Aligarh, 202002, Uttar Pradesh, India.
| | - Mohammad Afzal
- Section of Genetics, Department of Zoology, Faculty of Life Sciences, Aligarh Muslim University, Aligarh, 202002, Uttar Pradesh, India
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Abstract
Lead (Pb2+) is a non-essential metal with numerous industrial applications that have led to ts ubiquity in the environment. Thus, not only occupational-exposed individuals' health is compromised, but also that of the general population and in particular children. Notably, although the central nervous system is particularly susceptible to Pb2+, other systems are affected as well. The present study focuses on molecular mechanisms that underlie the effects that arise from the presence of Pb2+ in situ in the brain, and the possible toxic effects that follows. As the brain barriers represent the first target of systemic Pb2+, mechanisms of Pb2+ entry into the brain are discussed, followed by a detailed discussion on neurotoxic mechanisms, with special emphasis on theories of ion mimicry, mitochondrial dysfunction, redox imbalance, and neuroinflammation. Most importantly, the confluence and crosstalk between these events is combined into a cogent mechanism of toxicity, by intertwining recent and old evidences from humans, in vitro cell culture and experimental animals. Finally, pharmacological interventions, including chelators, antioxidants substances, anti-inflammatory drugs, or their combination are reviewed as integrated approaches to ameliorate Pb2+ harmful effects in both developing or adult organisms.
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Affiliation(s)
- Miriam B. Virgolini
- IFEC CONICET. IFEC-CONICET. Departamento de Farmacología, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba. Haya de la Torre y Medina Allende, Ciudad Universitaria, 5016, Córdoba, Argentina
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, USA and IM Sechenov First Moscow State Medical University (Sechenov University), 119146, Moscow, Russia
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Hernández-Plata I, Rodríguez VM, Tovar-Sánchez E, Carrizalez L, Villalobos P, Mendoza-Trejo MS, Mussali-Galante P. Metal brain bioaccumulation and neurobehavioral effects on the wild rodent Liomys irroratus inhabiting mine tailing areas. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2020; 27:36330-36349. [PMID: 32556984 DOI: 10.1007/s11356-020-09451-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Accepted: 05/26/2020] [Indexed: 06/11/2023]
Abstract
Ecotoxicological studies are necessary in order to evaluate the effects of environmental exposure of chemicals on wild animals and their ecological consequences. Particularly, neurobehavioral effects of heavy metal elements on wild rodents have been scarcely investigated. In the present study, we analyzed the effect of metal bioaccumulation (Pb, As, Mg, Ni, and Zn) in the brain and in the liver on exploratory activity, learning, memory, and on some dopaminergic markers in the wild rodent Liomys irroratus living inside mine tailings, at Huautla, Morelos, Mexico. We found higher Pb concentration but lower Zn in striatum, nucleus accumbens, midbrain, and hippocampus in exposed animals in comparison to rodents from the reference site. Exposed rodents exhibited anxious behavior evaluated in the open field, while no alterations in learning were found. However, they displayed slight changes in the memory test in comparison to reference group. The neurochemical evaluation showed higher levels of dopamine and 5-hydroxyindolacetic acid in midbrain, while lower levels of metabolites dihydroxyphenyl acetic acid and homovanillic acid in striatum of exposed rodents. In addition, mRNA expression levels of dopaminergic D2 receptors in nucleus accumbens were lower in animals from the mining zone than in animals from the reference zone. This is the first study that shows that chronic environmental exposure to metals results in behavioral and neurochemical alterations in the wild rodent L. irroratus, a fact that may comprise the survival of the individuals resulting in long-term effects at the population level. Finally, we suggest the use of L. irroratus as a sentinel species for environmental biomonitoring of mining sites.
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Affiliation(s)
- Isela Hernández-Plata
- Laboratorio de Investigaciones Ambientales, Centro de Investigación en Biotecnología, Universidad Autónoma del Estado de Morelos, Av. Universidad 1001, Col. Chamilpa, Cuernavaca, Morelos, México
| | - Verónica M Rodríguez
- Instituto de Neurobiología, Universidad Nacional Autónoma de México, Boulevard Juriquilla 3001, Querétaro, Querétaro, 76230, México
| | - Efraín Tovar-Sánchez
- Centro de Investigación para la Biodiversidad y Conservación, Universidad Autónoma del Estado de Morelos, Av. Universidad 1001, Col. Chamilpa, Cuernavaca, Morelos, México
| | - Leticia Carrizalez
- Coordinación para la Innovación y Aplicación de la Ciencia y la Tecnología, Universidad Autónoma de San Luis Potosí, Av. Sierra Leona #550, Col. Lomas 2a Sección, 78210, San Luis Potosí, San Luis Potosí, México
| | - Patricia Villalobos
- Instituto de Neurobiología, Universidad Nacional Autónoma de México, Boulevard Juriquilla 3001, Querétaro, Querétaro, 76230, México
| | - María Soledad Mendoza-Trejo
- Instituto de Neurobiología, Universidad Nacional Autónoma de México, Boulevard Juriquilla 3001, Querétaro, Querétaro, 76230, México
| | - Patricia Mussali-Galante
- Laboratorio de Investigaciones Ambientales, Centro de Investigación en Biotecnología, Universidad Autónoma del Estado de Morelos, Av. Universidad 1001, Col. Chamilpa, Cuernavaca, Morelos, México.
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8
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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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9
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Kynurenine Pathway as a New Target of Cognitive Impairment Induced by Lead Toxicity During the Lactation. Sci Rep 2020; 10:3184. [PMID: 32081969 PMCID: PMC7035386 DOI: 10.1038/s41598-020-60159-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Accepted: 02/07/2020] [Indexed: 12/31/2022] Open
Abstract
The immature brain is especially vulnerable to lead (Pb2+) toxicity, which is considered an environmental neurotoxin. Pb2+ exposure during development compromises the cognitive and behavioral attributes which persist even later in adulthood, but the mechanisms involved in this effect are still unknown. On the other hand, the kynurenine pathway metabolites are modulators of different receptors and neurotransmitters related to cognition; specifically, high kynurenic acid levels has been involved with cognitive impairment, including deficits in spatial working memory and attention process. The aim of this study was to evaluate the relationship between the neurocognitive impairment induced by Pb2+ toxicity and the kynurenine pathway. The dams were divided in control group and Pb2+ group, which were given tap water or 500 ppm of lead acetate in drinking water ad libitum, respectively, from 0 to 23 postnatal day (PND). The poison was withdrawn, and tap water was given until 60 PND of the progeny. The locomotor activity in open field, redox environment, cellular function, kynurenic acid (KYNA) and 3-hydroxykynurenine (3-HK) levels as well as kynurenine aminotransferase (KAT) and kynurenine monooxygenase (KMO) activities were evaluated at both 23 and 60 PND. Additionally, learning and memory through buried food location test and expression of KAT and KMO, and cellular damage were evaluated at 60 PND. Pb2+ group showed redox environment alterations, cellular dysfunction and KYNA and 3-HK levels increased. No changes were observed in KAT activity. KMO activity increased at 23 PND and decreased at 60 PND. No changes in KAT and KMO expression in control and Pb2+ group were observed, however the number of positive cells expressing KMO and KAT increased in relation to control, which correlated with the loss of neuronal population. Cognitive impairment was observed in Pb2+ group which was correlated with KYNA levels. These results suggest that the increase in KYNA levels could be a mechanism by which Pb2+ induces cognitive impairment in adult mice, hence the modulation of kynurenine pathway represents a potential target to improve behavioural alterations produced by this environmental toxin.
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Reis CF, de Souza ID, Morais DAA, Oliveira RAC, Imparato DO, de Almeida RMC, Dalmolin RJS. Systems Biology-Based Analysis Indicates Global Transcriptional Impairment in Lead-Treated Human Neural Progenitor Cells. Front Genet 2019; 10:791. [PMID: 31552095 PMCID: PMC6748217 DOI: 10.3389/fgene.2019.00791] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Accepted: 07/26/2019] [Indexed: 01/19/2023] Open
Abstract
Lead poisoning effects are wide and include nervous system impairment, peculiarly during development, leading to neural damage. Lead interaction with calcium and zinc-containing metalloproteins broadly affects cellular metabolism since these proteins are related to intracellular ion balance, activation of signaling transduction cascades, and gene expression regulation. In spite of lead being recognized as a neurotoxin, there are gaps in knowledge about the global effect of lead in modulating the transcription of entire cellular systems in neural cells. In order to investigate the effects of lead poisoning in a systemic perspective, we applied the transcriptogram methodology in an RNA-seq dataset of human embryonic-derived neural progenitor cells (ES-NP cells) treated with 30 µM lead acetate for 26 days. We observed early downregulation of several cellular systems involved with cell differentiation, such as cytoskeleton organization, RNA, and protein biosynthesis. The downregulated cellular systems presented big and tightly connected networks. For long treatment times (12 to 26 days), it was possible to observe a massive impairment in cell transcription profile. Taking the enriched terms together, we observed interference in all layers of gene expression regulation, from chromatin remodeling to vesicle transport. Considering that ES-NP cells are progenitor cells that can originate other neural cell types, our results suggest that lead-induced gene expression disturbance might impair cells’ ability to differentiate, therefore influencing ES-NP cells’ fate.
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Affiliation(s)
- Clovis F Reis
- Bioinformatics Multidisciplinary Environment - IMD, Federal University of Rio Grande do Norte, Natal, Brazil
| | - Iara D de Souza
- Bioinformatics Multidisciplinary Environment - IMD, Federal University of Rio Grande do Norte, Natal, Brazil
| | - Diego A A Morais
- Bioinformatics Multidisciplinary Environment - IMD, Federal University of Rio Grande do Norte, Natal, Brazil
| | - Raffael A C Oliveira
- Bioinformatics Multidisciplinary Environment - IMD, Federal University of Rio Grande do Norte, Natal, Brazil
| | - Danilo O Imparato
- Bioinformatics Multidisciplinary Environment - IMD, Federal University of Rio Grande do Norte, Natal, Brazil
| | - Rita M C de Almeida
- Institute of Physics and National Institute of Science and Technology: Complex Systems, Federal University of Rio Grande do Sul, Porto Alegre, Brazil
| | - Rodrigo J S Dalmolin
- Bioinformatics Multidisciplinary Environment - IMD, Federal University of Rio Grande do Norte, Natal, Brazil.,Department of Biochemistry - CB, Federal University of Rio Grande do Norte, Natal, Brazil
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11
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Chronic lead exposure decreases the expression of Huntingtin-associated protein 1 (HAP1) through Repressor element-1 silencing transcription (REST). Toxicol Lett 2019; 306:1-10. [DOI: 10.1016/j.toxlet.2019.02.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Revised: 01/27/2019] [Accepted: 02/06/2019] [Indexed: 02/06/2023]
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12
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Paschoalini AL, Savassi LA, Arantes FP, Rizzo E, Bazzoli N. Heavy metals accumulation and endocrine disruption in Prochilodus argenteus from a polluted neotropical river. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2019; 169:539-550. [PMID: 30476816 DOI: 10.1016/j.ecoenv.2018.11.047] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Revised: 09/21/2018] [Accepted: 11/11/2018] [Indexed: 05/20/2023]
Abstract
Heavy metals are considered major pollutants of aquatic environments due to the difficulty of metabolization and the bioaccumulative potential in tissues of aquatic organisms, especially fish muscle that is often used as food worldwide. In addition to causing cell damage, some metals such as aluminium (Al), cadmium (Cd), copper (Cu), and lead (Pb) can act as endocrine disrupting chemicals in fish. The Paraopeba and Abaete Rivers are important tributaries of the upper São Francisco River basin, but the Paraopeba River receives, along its course, the discharge of many types of effluents that affect fish species, including widely consumed species such as Prochilodus argenteus. This study evaluated histological and molecular changes caused by chronic exposure to heavy metals in P. argenteus from the Paraopeba River and compared this to fish from the non-impacted Abaete River. Sampled fish from both rivers were used in histological analyses and immunohistochemical assays. The results showed increased incidence of histopathologies and changes in number and morphology of germline cells in both sexes. In addition, up-regulated expression of oestrogens-induced proteins in the liver of males were detected in polluted environment. All the alterations were related to the concentration of metals in water and fish. The high concentration of various metals observed in water and fish from Paraopeba River serves as an alert to the environmental and public health regulatory authorities.
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Affiliation(s)
- A L Paschoalini
- Morphology department, Biological Sciences Institute, Federal University of Minas Gerais, UFMG, Belo Horizonte 30161-970, Minas Gerais, Brazil
| | - L A Savassi
- Morphology department, Biological Sciences Institute, Federal University of Minas Gerais, UFMG, Belo Horizonte 30161-970, Minas Gerais, Brazil
| | - F P Arantes
- Post-Graduate Program in Vertebrate Biology, Pontifical Catholic University of Minas Gerais, PUC Minas, Belo Horizonte 30535-610, Minas Gerais, Brazil
| | - E Rizzo
- Morphology department, Biological Sciences Institute, Federal University of Minas Gerais, UFMG, Belo Horizonte 30161-970, Minas Gerais, Brazil
| | - N Bazzoli
- Post-Graduate Program in Vertebrate Biology, Pontifical Catholic University of Minas Gerais, PUC Minas, Belo Horizonte 30535-610, Minas Gerais, Brazil.
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13
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Kluska K, Adamczyk J, Krężel A. Metal binding properties, stability and reactivity of zinc fingers. Coord Chem Rev 2018. [DOI: 10.1016/j.ccr.2018.04.009] [Citation(s) in RCA: 109] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Garza-Lombó C, Posadas Y, Quintanar L, Gonsebatt ME, Franco R. Neurotoxicity Linked to Dysfunctional Metal Ion Homeostasis and Xenobiotic Metal Exposure: Redox Signaling and Oxidative Stress. Antioxid Redox Signal 2018; 28:1669-1703. [PMID: 29402131 PMCID: PMC5962337 DOI: 10.1089/ars.2017.7272] [Citation(s) in RCA: 119] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
SIGNIFICANCE Essential metals such as copper, iron, manganese, and zinc play a role as cofactors in the activity of a wide range of processes involved in cellular homeostasis and survival, as well as during organ and tissue development. Throughout our life span, humans are also exposed to xenobiotic metals from natural and anthropogenic sources, including aluminum, arsenic, cadmium, lead, and mercury. It is well recognized that alterations in the homeostasis of essential metals and an increased environmental/occupational exposure to xenobiotic metals are linked to several neurological disorders, including neurodegeneration and neurodevelopmental alterations. Recent Advances: The redox activity of essential metals is key for neuronal homeostasis and brain function. Alterations in redox homeostasis and signaling are central to the pathological consequences of dysfunctional metal ion homeostasis and increased exposure to xenobiotic metals. Both redox-active and redox-inactive metals trigger oxidative stress and damage in the central nervous system, and the exact mechanisms involved are starting to become delineated. CRITICAL ISSUES In this review, we aim to appraise the role of essential metals in determining the redox balance in the brain and the mechanisms by which alterations in the homeostasis of essential metals and exposure to xenobiotic metals disturb the cellular redox balance and signaling. We focus on recent literature regarding their transport, metabolism, and mechanisms of toxicity in neural systems. FUTURE DIRECTIONS Delineating the specific mechanisms by which metals alter redox homeostasis is key to understand the pathological processes that convey chronic neuronal dysfunction in neurodegenerative and neurodevelopmental disorders. Antioxid. Redox Signal. 28, 1669-1703.
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Affiliation(s)
- Carla Garza-Lombó
- 1 Redox Biology Center and School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln , Lincoln, Nebraska.,2 Departamento de Medicina Genómica y Toxicología Ambiental, Instituto de Investigaciones Biomédicas , Universidad Nacional Autónoma de México, Mexico City, México
| | - Yanahi Posadas
- 3 Departamentos de Farmacología y de, Centro de Investigación y de Estudios Avanzados (CINVESTAV) , Mexico City, México .,4 Departamentos de Química, Centro de Investigación y de Estudios Avanzados (CINVESTAV) , Mexico City, México
| | - Liliana Quintanar
- 4 Departamentos de Química, Centro de Investigación y de Estudios Avanzados (CINVESTAV) , Mexico City, México
| | - María E Gonsebatt
- 2 Departamento de Medicina Genómica y Toxicología Ambiental, Instituto de Investigaciones Biomédicas , Universidad Nacional Autónoma de México, Mexico City, México
| | - Rodrigo Franco
- 1 Redox Biology Center and School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln , Lincoln, Nebraska
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You Y, Peng B, Ben S, Hou W, Sun L, Jiang W. Lead Neurotoxicity on Human Neuroblastoma Cell Line SH-SY5Y is Mediated via Transcription Factor EGR1/Zif268 Induced Disrupted in Scherophernia-1 Activation. Neurochem Res 2018; 43:1308-1316. [PMID: 29868983 DOI: 10.1007/s11064-018-2539-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Revised: 04/23/2018] [Accepted: 04/27/2018] [Indexed: 11/24/2022]
Abstract
Lead (Pb2+) is a well-known type of neurotoxin and chronic exposure to Pb2+ induces cognition dysfunction. In this work, the potential role of early growth response gene 1 (EGR1) in the linkage of Pb2+ exposure and disrupted in scherophernia-1 (DISC1) activity was investigated. Human neuroblastoma cell line SH-SY5Y was subjected to different concentrations of lead acetate (PbAc) to determine the effect of Pb2+ exposure on the cell viability, apoptosis, and activity of EGR1 and DISC1. Then the expression of EGR1 in SH-SY5Y cells was knocked down with specific siRNA to assess the function of EGR1 in Pb2+ induced activation of DISC1. The interaction between EGR1 and DISC1 was further validated with dual luciferase assay, Supershift electrophoretic mobility shift assay (EMSA), and chromatin immunoprecipitation (ChIP)-PCR. Administration of PbAc decreased cell viability and induced apoptosis in SH-SY5Y cells in a dose-dependent manner. Additionally, exposure to PbAc also up-regulated expression of EGR1 and DISC1 at all concentrations. Knockdown of EGR1 blocked the effect of PbAc on SH-SY5Y cells, indicating the central role of EGR1 in the function of Pb2+ on activity of DISC1. Based on the results of dual luciferase assay, Supershift EMSA, and ChIP-PCR, EGR1 mediated the effect of Pb2+ on DISC1 by directly bound to the promoter region of DISC1 gene. The current study elaborated the mechanism involved in the effect of Pb2+ exposure on expression of DISC1 for the first time: EGR1 activated by Pb2+ substitution of zinc triggered the transcription of DISC1 gene by directly binding to its promoter.
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Affiliation(s)
- Yuanyuan You
- Department of Genetic, Shenyang Maternity and Child Health Hospital, Shenyang, People's Republic of China
| | - Bo Peng
- Outpatient Department, China Medical University, Shenyang, People's Republic of China
| | - Songbin Ben
- Life Science College, Liaoning University, Shenyang, People's Republic of China
| | - Weijian Hou
- Department of Tissue Engineering, China Medical University, Shenyang, People's Republic of China
| | - Liguang Sun
- Department of Biochemical and Molecular Biology, China Medical University, No. 77 of Puhe Road, Beixin District, Shenyang, 110127, Liaoning, People's Republic of China.
| | - Wei Jiang
- Department of Biological Science, Liaoning Academy of Analytical Sciences, Shenyang, People's Republic of China
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16
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Yang M, Li Y, Hu L, Luo D, Zhang Y, Xiao X, Li G, Zhang L, Zhu G. Lead exposure inhibits expression of SV2C through NRSF. Toxicology 2018; 398-399:23-30. [DOI: 10.1016/j.tox.2018.02.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2017] [Revised: 02/11/2018] [Accepted: 02/27/2018] [Indexed: 12/31/2022]
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17
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de Souza ID, de Andrade AS, Dalmolin RJS. Lead-interacting proteins and their implication in lead poisoning. Crit Rev Toxicol 2018; 48:375-386. [DOI: 10.1080/10408444.2018.1429387] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Iara Dantas de Souza
- Bioinformatics Multidisciplinary Environment – IMD, Federal University of Rio Grande do Norte, Natal, Brazil
| | - Abraão Silveira de Andrade
- Bioinformatics Multidisciplinary Environment – IMD, Federal University of Rio Grande do Norte, Natal, Brazil
| | - Rodrigo Juliani Siqueira Dalmolin
- Bioinformatics Multidisciplinary Environment – IMD, Federal University of Rio Grande do Norte, Natal, Brazil
- Department of Biochemistry – CB, Federal University of Rio Grande do Norte, Natal, Brazil
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18
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Ordemann JM, Austin RN. Lead neurotoxicity: exploring the potential impact of lead substitution in zinc-finger proteins on mental health. Metallomics 2016; 8:579-88. [DOI: 10.1039/c5mt00300h] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This critical review focuses on one possible link between the cellular biology of lead and its neurotoxic effects: the link between Pb2+substitution for Zn2+in zinc-finger proteins and mental illness in adulthood.
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Bazrgar M, Goudarzi I, Lashkarbolouki T, Elahdadi Salmani M. Melatonin ameliorates oxidative damage induced by maternal lead exposure in rat pups. Physiol Behav 2015. [PMID: 26197271 DOI: 10.1016/j.physbeh.2015.06.040] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
During the particular period of cerebellum development, exposure to lead (Pb) decreases cerebellum growth and can result in selective loss of neurons. The detection and prevention of Pb toxicity is a major international public health priorities. This research study was conducted to evaluate the effects of melatonin, an effective antioxidant and free radical scavenger, on Pb induced neurotoxicity and oxidative stress in the cerebellum. Pb exposure was initiated on gestation day 5 with the addition of daily doses of 0.2% lead acetate to distilled drinking water and continues until weaning. Melatonin (10mg/kg) was given once daily at the same time. 21 days after birth, several antioxidant enzyme activities including superoxide dismutase (SOD) and glutathione peroxidase (GPx) were assayed. Thiobarbituric acid reactive substance (TBARS) levels were measured as a marker of lipid peroxidation. Rotarod and locomotor activity tests were performed on postnatal days (PDs) 31-33 and a histological study was performed after completion of behavioral measurements on PD 33. The results of the present work demonstrated that Pb could induce lipid peroxidation, increase TBARS levels and decrease GPx and SOD activities in the rat cerebellum. We also observed that Pb impaired performance on the rotarod and locomotor activities of rats. However, treatment with melatonin significantly attenuated the motoric impairment and lipid peroxidation process and restored the levels of antioxidants. Histological analysis indicated that Pb could decrease Purkinje cell count and melatonin prevented this toxic effect. These results suggest that treatment with melatonin can improve motor deficits and oxidative stress by protecting the cerebellum against Pb toxicity.
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Affiliation(s)
| | - Iran Goudarzi
- School of Biology, Damghan University, Damghan, Iran.
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20
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Qasemian Lemraski M, Soodi M, Fakhr Taha M, Zarei MH, Jafarzade E. Study of lead-induced neurotoxicity in neural cells differentiated from adipose tissue-derived stem cells. Toxicol Mech Methods 2015; 25:128-35. [DOI: 10.3109/15376516.2014.997949] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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21
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The Role of Heavy Metal Pollution in Neurobehavioral Disorders: a Focus on Autism. REVIEW JOURNAL OF AUTISM AND DEVELOPMENTAL DISORDERS 2014. [DOI: 10.1007/s40489-014-0028-3] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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22
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Protective effect of Thunbergia laurifolia (Linn.) on lead induced acetylcholinesterase dysfunction and cognitive impairment in mice. BIOMED RESEARCH INTERNATIONAL 2013; 2013:186098. [PMID: 24455676 PMCID: PMC3881658 DOI: 10.1155/2013/186098] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Accepted: 12/02/2013] [Indexed: 11/20/2022]
Abstract
Thunbergia laurifolia (linn., TL), a natural phenolic compound, has been reported to have many benefits and medicinal properties. The current study ascertains the total phenolic content present in TL aqueous leaf extract and also examines the antioxidant ability of the extract in preserving acetylcholinesterase (AChE) activity of mice exposed to lead in vivo and in vitro model. Mice were given lead acetate (Pb) in drinking water (1 g/L) together with TL 100 and 200 mg/kg/day. The result showed that Pb induced AChE dysfunction in both in vitro and in vivo studies. TL significantly prevented Pb induced neurotoxicity in a dose-dependent manner which was indicated by comparatively better performance of TL treated mice in Morris Water Maze Swimming Test and increased AChE activity in the tissue sample collected from the brains of these mice. TL also exhibited the greatest amount of phenolic content, which has a significant positive correlation with its antioxidant capacity (P < 0.05). Taken together, these data suggested that the total phenolic compounds in TL could exhibit antioxidant and in part neuroprotective properties. It may play a potential treatment strategy for Pb contamination.
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23
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Chan YH, Gao M, Wu W. Are newborn rat-derived neural stem cells more sensitive to lead neurotoxicity? Neural Regen Res 2013; 8:581-92. [PMID: 25206702 PMCID: PMC4145982 DOI: 10.3969/j.issn.1673-5374.2013.07.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2012] [Accepted: 01/05/2013] [Indexed: 01/01/2023] Open
Abstract
Lead ion (Pb2+) has been proven to be a neurotoxin due to its neurotoxicity on mammalian nervous system, especially for the developing brains of juveniles. However, many reported studies involved the negative effects of Pb2+ on adult neural cells of humans or other mammals, only few of which have examined the effects of Pb2+ on neural stem cells. The purpose of this study was to reveal the biological effects of Pb2+ from lead acetate [Pb (CH3COO)2] on viability, proliferation and differentiation of neural stem cells derived from the hippocampus of newborn rats aged 7 days and adult rats aged 90 days, respectively. This study was carried out in three parts. In the first part, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay (MTT viability assay) was used to detect the effects of Pb2+ on the cell viability of passage 2 hippocampal neural stem cells after 48-hour exposure to 0–200 μM Pb2+. In the second part, 10 μM bromodeoxyuridine was added into the culture medium of passage 2 hippocampal neural stem cells after 48-hour exposure to 0–200 μM Pb2+, followed by immunocytochemical staining with anti-bromodeoxyuridine to demonstrate the effects of Pb2+ on cell proliferation. In the last part, passage 2 hippocampal neural stem cells were allowed to grow in the differentiation medium with 0–200 μM Pb2+. Immunocytochemical staining with anti-microtubule-associated protein 2 (a neuron marker), anti-glial fibrillary acidic protein (an astrocyte marker), and anti-RIP (an oligodendrocyte marker) was performed to detect the differentiation commitment of affected neural stem cells after 6 days. The data showed that Pb2+ inhibited not only the viability and proliferation of rat hippocampal neural stem cells, but also their neuronal and oligodendrocyte differentiation in vitro. Moreover, increased activity of astrocyte differentiation of hippocampal neural stem cells from both newborn and adult rats was observed after exposure to high concentration of lead ion in vitro. These findings suggest that hippocampal neural stem cells of newborn rats were more sensitive than those from adult rats to Pb2+ cytotoxicity.
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Affiliation(s)
- Yan Ho Chan
- Department of Anatomy, Li Ka Shing Faculty of Medicine, the University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Mingyong Gao
- Department of Anatomy, Li Ka Shing Faculty of Medicine, the University of Hong Kong, Pokfulam, Hong Kong SAR, China ; Department of Spine Surgery, Renmin Hospital of Wuhan University, Wuhan 430000, Hubei Province, China
| | - Wutian Wu
- Department of Anatomy, Li Ka Shing Faculty of Medicine, the University of Hong Kong, Pokfulam, Hong Kong SAR, China ; State Key Laboratory of Brain and Cognitive Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region, China ; Research Center of Reproduction, Development and Growth, Li Ka Shing Faculty of Medicine, the University of Hong Kong, Pokfulam, Hong Kong Special Administrative Region, China ; GHM Institute of Central Nervous System Regeneration, Jinan University, Guangzhou 510630, Guangdong Province, China
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24
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Lead-induced cardiac and hematological alterations in aging Wistar male rats: alleviating effects of nutrient metal mixture. Biogerontology 2012; 13:359-68. [DOI: 10.1007/s10522-012-9380-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2011] [Accepted: 04/12/2012] [Indexed: 01/09/2023]
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25
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Basha DC, Rani MU, Devi CB, Kumar MR, Reddy GR. Perinatal lead exposure alters postnatal cholinergic and aminergic system in rat brain: reversal effect of calcium co-administration. Int J Dev Neurosci 2012; 30:343-50. [PMID: 22326442 DOI: 10.1016/j.ijdevneu.2012.01.004] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2011] [Accepted: 01/12/2012] [Indexed: 10/14/2022] Open
Abstract
Our earlier studies indicated the role of neurotransmitter systems in lead (Pb) induced behavioral perturbations. In this study, we examined the alterations in synaptosomal acetylcholine (ACh), epinephrine, dopamine, acetylcholinesterase (AChE), and mitochondrial monoamine oxidase (MAO) in the cerebellum and hippocampus of perinatally Pb-exposed rats. Rats (Wistar) were exposed to 0.2% Pb (Pb acetate in drinking water of mother) from gestational day 6 and the pups were exposed lactationally (through mother's milk) to Pb till weaning (postnatal day 21). Studies conducted on different postnatal days (PND 21, 28, 35 and 60) showed significant decreases in synaptosomal AChE and mitochondrial MAO activities, and increases in the levels of ACh, dopamine and epinephrine in the cerebellum and hippocampus of Pb-exposed rats. These alterations were greater at PND 35 and more pronounced in the cholinergic system (ACh and AChE) of hippocampus and the aminergic system (epinephrine, dopamine and MAO) of cerebellum. The total locomotor activity and exploratory behavior were also decreased significantly in Pb-exposed animals corresponding to the alterations observed in cholinergic and aminergic systems. Calcium administration together with Pb, however significantly reversed the Pb-induced alterations in transmitters and enzymes, as well as exploratory and motor behavior suggesting protective effect of calcium in Pb-exposed animals.
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Affiliation(s)
- D Chand Basha
- Department of Zoology, S.V. University, Tirupati 517502, India
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26
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Inorganic lead (Pb)- and mercury (Hg)-induced neuronal cell death involves cytoskeletal reorganization. Lab Anim Res 2011; 27:219-25. [PMID: 21998611 PMCID: PMC3188729 DOI: 10.5625/lar.2011.27.3.219] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2011] [Revised: 09/05/2011] [Accepted: 09/05/2011] [Indexed: 11/23/2022] Open
Abstract
Inorganic lead and mercury are widely spread xenobiotic neurotoxicants threatening public health. The exposure to inorganic lead and mercury results in adverse effects of poisoning including IQ deficit and peripheral neuropathy. Additionally, inorganic neurotoxicants have even more serious impact on earlier stages of embryonic development. This study was therefore initiated in order to determine the cytotoxic effects of lead and mercury in earlier developmental stages of chick embryo. Administration of inorganic lead and mercury into the chick embryo resulted in the prolonged accumulation of inorganics in the neonatal brain, with detrimental cytotoxicity on neuronal cells. Subsequent studies demonstrated that exposure of chick embryo to inorganic lead and mercury resulted in the reorganization of cytoskeletal proteins in the neonatal brain. These results therefore suggest that inorganics-mediated cytoskeletal reorganization of the structural proteins, resulting in neurocytotoxicity, is one of the underlying mechanisms by which inorganics transfer deleterious effects on central nervous system.
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27
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Hu Q, Fu H, Song H, Ren T, Li L, Ye L, Liu T, Dong S. Low-level lead exposure attenuates the expression of three major isoforms of neural cell adhesion molecule. Neurotoxicology 2010; 32:255-60. [PMID: 21182862 DOI: 10.1016/j.neuro.2010.12.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2010] [Revised: 12/10/2010] [Accepted: 12/11/2010] [Indexed: 10/18/2022]
Abstract
Toxic lead (Pb) exposure poses serious risks to human health, especially to children at developmental stages, even at low exposure levels. Neural cell adhesion molecule (NCAM) is considered to be a potential early target in the neurotoxicity of Pb due to its role in cell adhesion, neuronal migration, synaptic plasticity, and learning and memory. However, the effect of low-level Pb exposure on the specific expression of NCAM isoforms has not been reported. In the present study, we found that Pb could concentration-dependently (1-100 nM) inhibit the expression of three major NCAM isoforms (NCAM-180, -140, and -120) in primary cultured hippocampal neurons. Furthermore, it was verified that levels of all three major isoforms of NCAM were reduced by Pb exposure in human embryonic kidney (HEK)-293 cells transiently transfected with NCAM-120, -140, or -180 isoform cDNA constructs. In addition, low-level Pb exposure delayed the neurite outgrowth and reduced the survival rate of cultured hippocampal neurons at different time-points. Together, our results demonstrate that developmental low-level Pb exposure can attenuate the expression of all three major NCAM isoforms, which may contribute to the observed Pb-mediated neurotoxicity.
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Affiliation(s)
- Qiansheng Hu
- Department of Preventive Medicine, School of Public Health, Sun Yat-Sen University, Guangzhou 510080, China.
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28
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Li N, Yu ZL, Wang L, Zheng YT, Jia JX, Wang Q, Zhu MJ, Liu XL, Xia X, Li WJ. Increased tau phosphorylation and beta amyloid in the hipocampus of mouse pups by early life lead exposure. ACTA BIOLOGICA HUNGARICA 2010; 61:123-34. [PMID: 20519167 DOI: 10.1556/abiol.61.2010.2.1] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The aim of this study was to investigate the effects of maternal lead exposure on the learning and memory ability and expression of tau protein phosphorylation (P-tau) and beta amyloid protein (Abeta) in hippocampus of mice offspring. Pb exposure initiated from beginning of gestation to weaning. Pb acetate administered in drinking solutions was dissolved in distilled deionized water at the concentrations of 0.1%, 0.5% and 1% groups. On the 21 th of postnatal day, the learning and memory ability of the mouse pups was tested by Water Maze test and the Pb levels in blood and hippocampus of the offspring were also determined. The expression of P-tau and Abeta in hippocampus was measured by immunohistochemistry and Western blotting. The Pb levels in blood and hippocampus of all exposure groups were significantly higher than that of the control group ( P < 0.05). In Water Maze test, the performances of 0.5% and 1% groups were worse than that of the control group ( P < 0.05). The expression of P-tau and Abeta was increased in Pb exposed groups than that of the control group ( P < 0.05). Tau hyper-phosphorylation and Abeta increase in the hippocampus of pups may contribute to the impairment of learning and memory associated with maternal Pb exposure.
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Affiliation(s)
- N Li
- Zhengzhou University College of Public Health Zhengzhou 450001 China
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29
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Lead affects apoptosis and related gene XIAP and Smac expression in the hippocampus of developing rats. Neurochem Res 2010; 35:473-9. [PMID: 19911273 DOI: 10.1007/s11064-009-0083-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/14/2009] [Indexed: 02/05/2023]
Abstract
Lead (Pb) exposure poses devastating effects on central nervous system development of children. To replicate aspects of this neurotoxicity, we examined the effect of lead on the expression of apoptosis and of apoptosis-related genes, XIAP (X chromosome-linked inhibitor of apoptosis protein) and Smac (second mitochondrial activator of caspase), in the hippocampus of developing rats. A total of 48 rats (30-day old) were randomly divided into four groups for intragastrical perfusion of lead acetate [Pb(Ac)2]: untreated, low (2 mg/kg/d), medium (20 mg/kg/d), and high (200 mg/kg/d) dose groups. Pb content was determined in blood, and the apoptosis indexes and XIAP and Smac gene expression were analyzed in the hippocampus. There was a significant difference in apoptosis indexes (AI) between the exposed and control groups (p < 0.01). AI was highest in the high exposure group. XIAP gene expression was reduced in the exposed groups and the expression was negatively correlated with blood lead levels (BLLs) (p < 0.05). But the four groups did not differ in the expression of Smac (p > 0.05). Our data indicate that exposure to Pb(Ac)2 caused a dose-dependent and significant increase of apoptosis in the hippocampus of developing rats through depressing the expression of the XIAP but not the Smac genes.
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30
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Brubaker CJ, Dietrich KN, Lanphear BP, Cecil KM. The influence of age of lead exposure on adult gray matter volume. Neurotoxicology 2010; 31:259-66. [PMID: 20226811 DOI: 10.1016/j.neuro.2010.03.004] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2010] [Revised: 02/08/2010] [Accepted: 03/03/2010] [Indexed: 12/12/2022]
Abstract
Childhood lead exposure is associated with decreased cognitive abilities and executive functioning localized within the prefrontal cortex. Several studies have observed stronger associations between blood lead measurements obtained later in life than earlier measures, but there are no imaging studies investigating the developmental trajectory of blood lead levels taken during childhood on adult gray matter volume. In this study, we recruited 157 adults (20.8+/-1.5 years of age) from the Cincinnati Lead Study to undergo high resolution volumetric magnetic resonance imaging. Adjusted voxel-wise regression analyses were performed for associations between adult gray matter volume loss and yearly mean blood lead levels from 1 to 6 years of age in the entire cohort and by sex. We observed significant inverse associations between gray matter volume loss and annual mean blood lead levels from 3 to 6 years of age. The extent of prefrontal gray matter associated with yearly mean blood lead levels increased with advancing age of the subjects. The inverse associations between gray matter volume loss and yearly mean blood lead measurements were more pronounced in the frontal lobes of men than women. Analysis of women yielded significantly weaker associations between yearly mean blood lead levels and gray matter volume at all ages than either men or the combined cohort of men and women together. These results suggest that blood lead concentrations obtained during later childhood demonstrate greater loss in gray matter volume than childhood mean or maximum values. The relationship between childhood blood lead levels and gray matter volume loss was predominantly observed in the frontal lobes of males. This study demonstrates that maximum blood lead levels do not fully account for gray matter changes associated with childhood lead exposure, particularly in the frontal lobes of young men.
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Affiliation(s)
- Christopher J Brubaker
- Cincinnati Children's Environmental Health Center, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, OH, USA
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31
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Prasanthi RPJ, Devi CB, Basha DC, Reddy NS, Reddy GR. Calcium and zinc supplementation protects lead (Pb)-induced perturbations in antioxidant enzymes and lipid peroxidation in developing mouse brain. Int J Dev Neurosci 2009; 28:161-7. [PMID: 20036325 DOI: 10.1016/j.ijdevneu.2009.12.002] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2009] [Revised: 12/15/2009] [Accepted: 12/15/2009] [Indexed: 11/17/2022] Open
Abstract
Several studies have implicated oxidative stress as one of the important mechanisms of toxic effects of lead (Pb). In the present study we tested the beneficial effects of calcium (Ca2+) and zinc (Zn2+) in protecting the Pb-induced oxidative stress in the brains of developing and adult mice. Mice were lactationally exposed to 0.2% Pb and supplemented with either calcium (Ca2+) or zinc (Zn2+) and the mitochondrial antioxidant enzymes [superoxide dismutase (SOD), xanthine oxidase (XO) and catalase (CAT)] and lipid peroxidation (LP) were analyzed in cortex, hippocampus, cerebellum and medulla of brains excised on postnatal day (PND) 14, 21, 28 and 3 months. The levels of free radicals were measured using direct Electron Paramagnetic Resonance (EPR) spectroscopy. Exposure to Pb resulted a significant decrease in the activities of SOD, XO and CAT while the LP levels were significantly increased in different brain regions. Evaluation of EPR signals and g-values showed abundant accumulation of free radicals in different regions of the brain following Pb exposure. Interestingly the supplementation with Ca2+ or Zn2+ reversed the Pb-induced effects on antioxidant enzymes, LP and free radical formation; however Zn2+ supplementation appeared to be more protective. These findings strongly support that zinc and calcium supplementation significantly protect the Pb-induced oxidative stress, a major contributing factor to neurotoxicity.
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Affiliation(s)
- R P Jaya Prasanthi
- Department of Pharmacology, Physiology and Therapeutics, University of North Dakota School of Medicine and Health Sciences, Grand Forks, ND 58203, USA
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Li N, Yu ZL, Wang L, Zheng YT, Jia JX, Wang Q, Zhu MJ, Liu XH, Xia X, Li WJ. Early-life lead exposure affects the activity of TNF-alpha and expression of SNARE complex in hippocampus of mouse pups. Biol Trace Elem Res 2009; 132:227-38. [PMID: 19888558 DOI: 10.1007/s12011-009-8551-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/26/2009] [Accepted: 10/12/2009] [Indexed: 10/20/2022]
Abstract
This study aims to investigate the effects of maternal lead exposure on learning and memory ability and the protein expression of TNF-alpha and SNARE complex (SNAP-25, VAMP-2, and Syntaxin 1A) in hippocampus of mice offspring. Pb exposure was initiated from beginning of gestation to weaning. Pb acetate administered in drinking solutions was dissolved in distilled deionized water at 0.1%, 0.5%, and 1% groups, respectively. On the PND21, the learning and memory ability of mouse pups was tested by water maze test, and the Pb levels in their blood and hippocampus were also determined. The protein expression of TNF-alpha and SNARE complex in hippocampus was measured by immunohistochemistry and Western blotting. The Pb levels in blood and hippocampus of all exposure groups were significantly higher than control group (P < 0.05). In the water maze test, the performances of 0.5% and 1% groups were worse than that of control group (P < 0.05). The expression of TNF-alpha, Syntaxin 1A, and VAMP-2 was increased in Pb-exposed groups comparing control group (P < 0.05), but the expression of SNAP-25 was decreased (P < 0.05). Up-regulation of TNF-alpha and disturbance of SNARE expression in the hippocampus of pups may contribute to impairment of learning and memory ability associated with maternal Pb exposure.
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Affiliation(s)
- N Li
- College of Public Health, Zhengzhou University, Zhengzhou 450001, China
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Sanders T, Liu Y, Buchner V, Tchounwou PB. Neurotoxic effects and biomarkers of lead exposure: a review. REVIEWS ON ENVIRONMENTAL HEALTH 2009; 24:15-45. [PMID: 19476290 PMCID: PMC2858639 DOI: 10.1515/reveh.2009.24.1.15] [Citation(s) in RCA: 480] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Lead, a systemic toxicant affecting virtually every organ system, primarily affects the central nervous system, particularly the developing brain. Consequently, children are at a greater risk than adults of suffering from the neurotoxic effects of lead. To date, no safe lead-exposure threshold has been identified. The ability of lead to pass through the blood-brain barrier is due in large part to its ability to substitute for calcium ions. Within the brain, lead-induced damage in the prefrontal cerebral cortex, hippocampus, and cerebellum can lead to a variety of neurologic disorders. At the molecular level, lead interferes with the regulatory action of calcium on cell functions and disrupts many intracellular biological activities. Experimental studies have also shown that lead exposure may have genotoxic effects, especially in the brain, bone marrow, liver, and lung cells. Knowledge of the neurotoxicology of lead has advanced in recent decades due to new information on its toxic mechanisms and cellular specificity. This paper presents an overview, updated to January 2009, of the neurotoxic effects of lead with regard to children, adults, and experimental animals at both cellular and molecular levels, and discusses the biomarkers of lead exposure that are useful for risk assessment in the field of environmental health.
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Affiliation(s)
- Talia Sanders
- Molecular Toxicology Research Laboratory, NIH RCMI - Center for Environmental Health, College of Science, Engineering, and Technology, Jackson State University, Jackson, MS, USA
| | - Yiming Liu
- Molecular Toxicology Research Laboratory, NIH RCMI - Center for Environmental Health, College of Science, Engineering, and Technology, Jackson State University, Jackson, MS, USA
| | | | - Paul B. Tchounwou
- Molecular Toxicology Research Laboratory, NIH RCMI - Center for Environmental Health, College of Science, Engineering, and Technology, Jackson State University, Jackson, MS, USA
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Kirberger M, Yang JJ. Structural differences between Pb2+- and Ca2+-binding sites in proteins: implications with respect to toxicity. J Inorg Biochem 2008; 102:1901-9. [PMID: 18684507 DOI: 10.1016/j.jinorgbio.2008.06.014] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2008] [Revised: 06/20/2008] [Accepted: 06/23/2008] [Indexed: 11/19/2022]
Abstract
Pb(2+) is known to displace physiologically-relevant metal ions in proteins. To investigate potential relationships between Pb(2+)/protein complexes and toxicity, data from the protein data bank were analyzed to compare structural properties of Pb(2+)- and Ca(2+)-binding sites. Results of this analysis reveal that the majority of Pb(2+) sites (77.1%) involve 2-5 binding ligands, compared with 6+/-2 for non-EF-Hand and 7+/-1 for EF-Hand Ca(2+)-binding sites. The mean net negative charge by site (1.7) fell between values noted for non-EF-Hand (1+/-1) and EF-Hand (3+/-1). Oxygen is the dominant ligand for both Pb(2+) and Ca(2+), but Pb(2+) binds predominantly with sidechain Glu (38.4%), which is less prevalent in both non-EF-Hand (10.4%) and EF-Hand (26.6%) Ca(2+)-binding sites. A comparison of binding geometries where Pb(2+) has replaced Ca(2+) in calmodulin (CaM) and Zn(2+) in 5-aminolaevulinic acid dehydratase (ALAD) revealed protein structural changes that appear to be unrelated to ionic displacement. Structural changes observed with CaM may be related to opportunistic binding of Pb(2+) in regions of high electrostatic charge, whereas ALAD may bind multiple Pb(2+) ions in the active site. These results suggest that Pb(2+) adapts to structurally-diverse binding geometries and that opportunistic binding may play an active role in molecular metal toxicity.
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Affiliation(s)
- Michael Kirberger
- Center for Drug Design and Biotechnology, Department of Chemistry, Georgia State University, 50 Decatur Street, 550 NSC, Atlanta, GA 30303, USA
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Kermani S, Karbalaie K, Madani SH, Jahangirnejad AA, Eslaminejad MB, Nasr-Esfahani MH, Baharvand H. Effect of lead on proliferation and neural differentiation of mouse bone marrow-mesenchymal stem cells. Toxicol In Vitro 2008; 22:995-1001. [PMID: 18381235 DOI: 10.1016/j.tiv.2008.02.009] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2007] [Revised: 01/02/2008] [Accepted: 02/08/2008] [Indexed: 11/29/2022]
Abstract
Bone marrow-mesenchymal stem cells (MSCs) are considered to be an ideal source of stem cells for assessing the effects of environmental toxins on the proliferation, multipotency and differentiation of adult stem cells. The aim of this study was to investigate the effect of lead on the proliferation and neuronal differentiation of murine MSCs. MTT assay used in this study revealed that while the proliferation of MSCs is sensitive to higher than 10 microM lead, a 50% reduction in the rate of their proliferation can be achieved in the presence of 60 microM lead. The results of immunocytochemistry and RT-PCR showed that beta-mercaptoethanol induced-neuronal differentiation is also reduced after the treatment of MSCs by 60 microM lead. Furthermore, the comet assay analysis of MSCs showed a substantial increase in DNA damage in the lead treated cells compared to the control. In conclusion our results revealed for the first time that lead is not only cytotoxic to the survival and proliferation of MSCs but also inhibits their differentiation to neurons in a dose-dependant manner. Therefore, MSCs appear to be an alternative method for assessing the cytotoxic effects of such environmental hazards.
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Affiliation(s)
- Shabnam Kermani
- Department of Stem Cells, Cell Science Research Center, Royan Institute, Esfahan Campus, PO Box 8158968433, Esfahan, Iran
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Reddy GR, Devi BC, Chetty CS. Developmental lead neurotoxicity: Alterations in brain cholinergic system. Neurotoxicology 2007; 28:402-7. [PMID: 16678265 DOI: 10.1016/j.neuro.2006.03.018] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2005] [Accepted: 03/10/2006] [Indexed: 10/24/2022]
Abstract
Developing brain has been shown to be susceptible to the neurotoxic effects of lead (Pb). Our earlier studies (Reddy GR, Riyaz Basha Md, Devi CB, Suresh A, Baker JL, Shafeek A, Heinz J, Chetty CS. Lead induced effects on acetylcholinesterase activity in cerebellum and hippocampus of developing rat. Int J Devl Neurosci 2003;21:347-52) have shown decrease in acetylcholinesterase (AChE) activity in the crude homogenates of cerebellum and hippocampus of rat brain exposed to Pb. In this study, we have further examined in detail, the alterations in AChE activity and acetylcholine (ACh) levels in different brain regions using histochemical and spectrophotometric methods. Rats were lactationally exposed to low level (0.2%) and high level (1%) Pb. The studies were conducted in young (1 month) and adult (3 months) rats. Pb exposure significantly decreased the specific activity of AChE and increased the levels of ACh in the synaptosomal fractions of cerebellum, hippocampus and cerebral cortex in a dose- and age-dependent manner. These alterations in AChE and ACh were more predominant in young rat brain as compared to adult brain. Maximum AChE activity and ACh level as well as maximum alterations following Pb exposure were observed in synaptosomes of hippocampus. Histochemical studies also showed higher AChE activity in the hippocampal region compared to other areas of brain as revealed by the intensity of AChE staining. Though high level Pb exposure remarkably decreased the intensity of AChE staining in the dentate gyrus, CA2 and CA3 areas of hippocampus, and different cell layers of cortex and cerebellum, highly significant loss of AChE activity was observed in the CA3 region of hippocampus, molecular layer of cerebellum and cortical cell layers. These data suggest that Pb exposure may selectively affect cholinergic system in brain areas controlling learning and cognitive behavior.
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Affiliation(s)
- Gottipolu R Reddy
- Department of Zoology, Sri Venkateswara University, Tirupati 517 502, AP, India.
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Suresh C, Dennis AO, Heinz J, Vemuri MC, Chetty CS. Melatonin protection against lead-induced changes in human neuroblastoma cell cultures. Int J Toxicol 2007; 25:459-64. [PMID: 17132604 DOI: 10.1080/10915810600959576] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The nervous system is the primary target for low-levels of lead (Pb) exposure and the developing brain appears to be especially vulnerable to Pb neurotoxicity. Chronic low-level Pb exposure causes growth retardation and intellectual impairment. In the present study the protective effect of melatonin during exposure to low-levels of Pb in human SH-SY5Y neuroblastoma cell cultures was assessed. The cells were exposed to Pb (0.01 to 10 microM) for 48 h. Pb inhibited the proliferation of neuroblastoma cells significantly in a concentration-dependent manner. A 50% inhibition (IC50) of cell proliferation was observed at about 5 microM Pb. Pb decreased (16% to 62%) the levels of total cellular glutathione (GSH) in a concentration (0.1 to 10 microM)-dependent manner. Exposure of cells to Pb (5 microM) for 48 h resulted in an eightfold increase in caspase-3 activity and prostaglandin E2 (PGE2) level. Pretreatment with melatonin (10 microM) blocked the effects of Pb on GSH content and caspase-3 activity, and showed significant improvement in reducing the level of PGE2. The results suggest that some of the neurotoxic effects of Pb may be partly mediated by apoptosis and pretreatment with melatonin can prevent these effects. The present study asserts the neuroprotective effect of melatonin in conditions of Pb-induced toxicity in neuroblastoma cell cultures.
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Prasanthi RP, Reddy GH, Reddy GR. Calcium or zinc supplementation reduces lead toxicity: assessment of behavioral dysfunction in young and adult mice. Nutr Res 2006. [DOI: 10.1016/j.nutres.2006.09.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Chetty CS, Vemuri MC, Reddy GR, Suresh C. Protective effect of 17-beta-estradiol in human neurocellular models of lead exposure. Neurotoxicology 2006; 28:396-401. [PMID: 16678263 DOI: 10.1016/j.neuro.2006.03.012] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2005] [Accepted: 03/10/2006] [Indexed: 11/16/2022]
Abstract
The developing nervous system has long been recognized as a primary target site for lead (Pb)-induced toxicity. Pb-exposure causes cognitive dysfunction, growth retardation, hyperactivity and neurochemical deficits in animals and humans. In the present study the effects of 17-beta-estradiol on human SH-SY5Y neuroblastoma cells in culture exposed to low-levels of Pb were assessed. The cells were exposed to Pb (0.01-10 microM) for 48 h and cell proliferation was determined by the MTT reduction assay. Pb significantly inhibited the proliferation and growth of neuroblastoma cells in a concentration-dependent manner. A 50% inhibition (IC50) in the proliferation of cells was observed with 5 microM Pb. Exposure of cells to Pb (5 microM) for 48 h resulted in a significant increase (+732% of control) in caspase-3 activity, an indicator of apoptosis and total cellular prostaglandin E2 level (+1180% of control), marker of programmed cell death/neuronal cell loss. Pretreatment with 17-beta-estradiol (10 nM) effectively blocked the effects of Pb on caspase-3 activity but not prostaglandin E2 level. Further, Pb but not 17-beta-estradiol in a concentration (0.1-10 microM)-dependent manner effectively decreased (38-84%) the cellular concentration of glutathione (GSH), an important intracellular antioxidant. However, the effect of Pb on GSH level was effectively blocked when pretreated with 17-beta-estradiol. The data indicate that even low concentrations of Pb can be detrimental and potentially toxic to the developing brain. In conclusion, these results suggest that at least some of the neurotoxic effects of Pb may be mediated by apoptosis, which by pretreatment with 17-beta-estradiol can be prevented. This study further confirms previous reports of 17-beta-estradiol acting as a neuroprotective and antiapoptotic agent during induced toxic stress conditions.
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Abstract
Alzheimer's disease (AD) is a progressive neurodegenerative disorder whose clinical manifestations appear in old age. The hallmark pathological features of AD (amyloid plaques and associated proteins) are present in normal aging indivduals, suggesting that AD may result from the acceleration of normal age-related processes in the brain. The sporadic nature of most AD cases strongly argues for an environmental link that may drive AD pathogenesis; however, it is unclear when this environmental stress may occur. Therefore it is important to identify an environmental trigger(s) and to pinpoint the period during which such factors pose the greatest risk. Recently, we reported that developmental exposure of rats to the xenobiotic metal lead (Pb) resulted in a delayed overexpression (20 months later) of the amyloid precursor protein (APP) and its amyloidogenic Abeta product. Similarly, aged monkeys exposed to Pb as infants also responded in the same way. These data suggest that environmental influences occurring during brain development predetermine the expression and regulation of APP later in life, potentially influencing the course of amyloidogenesis, and argue for both an environmental trigger and a developmental origin of AD. In this review, we present evidence for the developmental basis of neurodegeneration and discuss mechanisms that may explain how perturbations during development can have long-term or delayed consequences in the aging brain.
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Affiliation(s)
- Nasser H Zawia
- Neurotoxicology and Epigenomics Lab, Department of Biomedical and Pharmaceutical Sciences, University of Rhode Island, Kingston 02881, USA.
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41
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Tyree MM, Dalgard C, O'Neill JT. Impact of room air resuscitation on early growth response gene-1 in a neonatal piglet model of cerebral hypoxic ischemia. Pediatr Res 2006; 59:423-7. [PMID: 16492983 DOI: 10.1203/01.pdr.0000199908.30751.ef] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Early growth response gene-1 (Egr-1) is up-regulated by hypoxia-ischemia (HI) and reactive oxygen species (ROS) in adult animals, functioning as a master switch in inflammation and thrombogenesis. We hypothesized that resuscitation from HI with 100% O2 would result in greater Egr-1 expression, ROS, and cell death (CD) in the brains of newborn piglets than 21% O2. Two control groups breathed 21% O2 for 1 h followed by 21% or 100% O2 for 1 h. Two HI groups underwent carotid artery occlusion and breathed 8-12% O2 for 1 h followed by occlusion release and 21% or 100% O2 for 1 h. Brain Egr-1 mRNA and protein were analyzed via quantitative PCR and Western blot. CD and ROS were measured by fluorescence microscopy. Egr-1 mRNA expression increased throughout the brain in response to HI with regional heterogeneity, but protein levels did not. Resuscitation with 100% oxygen did not cause any additional Egr-1 mRNA, Egr-1 protein, CD, or ROS production as compared with 21% oxygen. There was no difference in physiologic recovery after HI with room air compared with 100% O2 resuscitation. However, 100% O2 administration was associated with increased CD in the brainstem independent of HI. Therefore, 100% O2 may have been toxic to some brainstem cells and potentially have significance in long-term neurologic sequelae seen after neonatal HI/resuscitation. Egr-1 protein levels may be tightly regulated in an attempt to diminish neurotoxicity or to enhance plasticity at this stage of development.
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Affiliation(s)
- Melissa M Tyree
- Department of Pediatrics, Uniformed Services University of the Helath Sciences, Bethesda, MD 20814, USA
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42
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Chen SS, Lin CH, Chen TJ. Lead-induced attenuation in the aggregation of acetylcholine receptors during the neuromuscular junction formation. Toxicol Lett 2005; 159:89-99. [PMID: 15916872 DOI: 10.1016/j.toxlet.2005.04.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2005] [Revised: 04/27/2005] [Accepted: 04/29/2005] [Indexed: 11/18/2022]
Abstract
Lead (Pb2+) toxicity is more common in children and is associated with cognitive deficits, which may reflect lead-induced changes in central synaptic development and function. Aside from neurotoxicity, lead exposure may also impact mature neuromuscular junction (NMJ) and cause muscle weakness. NMJ is known as a peripheral cholinergic synapse and its signaling cascades responsible for development are similar to those for the central synapses. However, the effect of lead exposure on the formation of NMJ in mammals is unclear. In the present study, a NG108-15/C2C12 coculture model was used to measure the acetylcholine receptor (AChR) aggregates formed on the myotubes which was an early hallmark for the NMJ formation. AChR aggregates were identified by alpha-bungarotoxin under fluorescent microscope. Single dose of lead acetate with final concentrations at 10(-3), 10(-1), or 10 microM was applied to dishes at the beginning of coculturing. Following 3-day exposure, although NG108-15 cells could extend long neurites to nearby myotubes, obvious dose-dependent attenuation in AChR aggregation was shown. The averaged area of an AChR aggregate, the averaged number of AChR aggregates per myotube, and the total area of AChR aggregates per myotube were all significantly decreased. In addition, the distribution percentages of various sizes of AChR aggregates showed that almost half of the AChR aggregates were formed with a size of 2-5 microm2 regardless of lead exposure. After treating 10 microM of lead acetate, significantly more AChR aggregates ranged from 2 to 20 microm2 were formed and significantly less AChR aggregates larger than 20 microm2 were formed. These results indicated that lead exposure reduced the extent of AChR aggregation concerning both the size and number of AChR aggregates and large AChR aggregates could hardly be formed after acute high-level lead exposure. No significant change was found in the total amount of AChRs on the myotubes after lead exposure, which indicated that the attenuation of AChR aggregation was not caused by reducing the synthesis of AChRs but by remaining dispersed pattern of AChRs on the myotubes. These data suggest that lead exposure exerts detrimental effects on the formation of NMJ.
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Affiliation(s)
- Shun-Sheng Chen
- Department of Neurology, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University, Kaohsiung County, Taiwan
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Huang F, Schneider JS. Effects of lead exposure on proliferation and differentiation of neural stem cells derived from different regions of embryonic rat brain. Neurotoxicology 2005; 25:1001-12. [PMID: 15474618 DOI: 10.1016/j.neuro.2004.03.010] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2004] [Accepted: 03/15/2004] [Indexed: 10/26/2022]
Abstract
Lead is a potent neurotoxin, causing brain damage and cognitive deficits in children even at low exposure levels. Although lead neurotoxicity can occur after prenatal or postnatal exposure, little is known of the effects of lead on embryonic neural stem cells (NSCs) or the extent to which NSCs originating in different brain regions may be differentially sensitive to the effects of lead exposure. The present study examined the effects of lead on proliferation and differentiation of neural stem cells (NSCs) originating from E15 rat cortex (CX), striatum (ST) or ventral mesencephalon (VM). Free-floating neurospheres were grown under standard conditions or in lead (0.01-100 microM)-containing conditioned media for 5 days and proliferation assessed by 3H-thymidine uptake. In other studies, control and lead-exposed neurospheres were collected, dissociated and re-plated in control or lead-containing differentiation media for 7 days. Cells were immunostained for visualization of mature neural and glial markers and counted. Lead exposure (0.01-10 microM) had no effect on neurosphere viability but caused a significant dose-dependent inhibition of proliferation in VM and ST but not CX neurospheres. The number of MAP2 positive neurons differentiated from lead-exposed neurospheres of VM and ST origin (but not CX) was significantly decreased from control as were the number of oligodendrocytes obtained, regardless of their region of origin. In contrast, lead exposure significantly increased the number of astrocytes obtained regardless of site of origin. These data suggest that even low levels of lead can differentially affect proliferation and differentiation of embryonic NSCs originating from different brain regions and supports the need for prevention of prenatal lead exposure.
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Affiliation(s)
- Funan Huang
- Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, 1020 Locust Street, 521 JAH Philadelphia, PA 19107, USA
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44
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Toscano CD, McGlothan JL, Guilarte TR. Lead exposure alters cyclic-AMP response element binding protein phosphorylation and binding activity in the developing rat brain. BRAIN RESEARCH. DEVELOPMENTAL BRAIN RESEARCH 2003; 145:219-28. [PMID: 14604762 DOI: 10.1016/j.devbrainres.2003.08.004] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
We examined the effect of lead (Pb(2+)) exposure during development on cyclic-AMP response element binding protein (CREB) expression and phosphorylation in cortical and hippocampal nuclear extracts at postnatal (PN) days 7, 14, 21 and 50. We also examined the binding of CREB family proteins to the cyclic-AMP response element (CRE) using a novel filter-binding assay that provides a quantitative measure of binding kinetics. In the hippocampus and cerebral cortex of control rats, CREB and phospho-CREB (pCREB; serine-133) expression is highest at PN7 and decreases steadily until PN50. Developmental Pb(2+) exposure does not affect total CREB levels but decreases pCREB levels at PN14 and PN50 in the cortex and at PN50 in the hippocampus. Using the filter-binding assay, we measured a 30% decrease in B(max) and 38% decrease in the Kd of CREB family proteins for the CRE in PN50 hippocampal nuclear fractions prepared from Pb(2+)-exposed rats. A similar, but nonsignificant, trend is observed in the cortex of PN50 lead-exposed rats. In addition, a 70% increase in the B(max) was observed in the cortex of PN14 lead-exposed rats without a significant change in the Kd. These disruptions in pCREB expression and binding activity of CREB family members during the ontogeny of the rat brain begin to decipher intracellular mechanisms of Pb(2+) neurotoxicity.
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Affiliation(s)
- Christopher D Toscano
- Department of Environmental Health Sciences, The Johns Hopkins University, Bloomberg School of Public Health, 615 North Wolfe Street, Room W2001, Baltimore, MD 21205, USA
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Reddy GR, Basha MR, Devi CB, Suresh A, Baker JL, Shafeek A, Heinz J, Chetty CS. Lead induced effects on acetylcholinesterase activity in cerebellum and hippocampus of developing rat. Int J Dev Neurosci 2003; 21:347-52. [PMID: 12927583 DOI: 10.1016/s0736-5748(03)00071-6] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
Abstract
Exposure to low-levels of lead (Pb) during early development has been implicated in behavioral abnormalities and cognitive deficits in children. The present study is focused on developmental changes in hippocampus and cerebellum of rats following perinatal exposure to Pb. Pregnant rats were exposed to 0.2% Pb-acetate from gestation day 6 (GD 6) through postnatal day (PND) 21 and the activity levels of acetylcholinesterase (AChE) were estimated in cerebellum and hippocampus of pups at specific time points for 5 weeks. In both the brain regions, Pb-exposure decreased AChE activity with an increase in age. Histochemical observations conducted in 35 days old rat brain showed decreased AChE activity conspicuously in stratum oriens and dentate gyrus of hippocampus, and molecular and granule cell layers of cerebellum. In vitro studies conducted in 35 days old rat brain showed a considerable decrease in the specific activity of AChE at high concentrations (50-100 microM) of Pb in a concentration-dependent manner. However, at low concentrations (5-20 microM), Pb failed to produce such changes. In the presence of eserine (physostigmine), the specific inhibitor of AChE, the inhibitory effect of Pb was potentiated and this was more pronounced at low-concentrations of Pb. The behavioral responses in open-field also showed a significant decrease in both Pb exposed as well as eserine administered rats. These data suggest that low-level perinatal Pb-exposure induces alterations in cholinergic system in the cerebellum and hippocampus of developing brain even after the withdrawal of Pb-exposure, that may contribute to behavioral and learning deficits.
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Affiliation(s)
- Gottipuolu R Reddy
- Department of Natural Sciences and Mathematics, Savannah State University, P.O. Box 20600, Savannah, GA 31404, USA
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Atkins DS, Basha MR, Zawia NH. Intracellular signaling pathways involved in mediating the effects of lead on the transcription factor Sp1. Int J Dev Neurosci 2003; 21:235-44. [PMID: 12850056 DOI: 10.1016/s0736-5748(03)00067-4] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
Abstract
It has been well established that exposure to Pb during critical periods of brain development results in both cognitive and behavioral deficits. Although the mechanism by which Pb induces developmental neurotoxicity is unknown, it may involve alterations in transcription of genes that are essential for growth and differentiation. Recent studies reveal that Pb interferes with growth and differentiation by acting on the transcription factor Sp1. Pb-induced changes in the activity of Sp1 may be consequent to alterations in intermediates in signal transduction pathways. This study examines both in vivo and in vitro the role of signaling factors in mediating the effects of Pb on Sp1 DNA-binding. Hippocampal developmental profiles of Sp1 DNA-binding, PKC, and MAPK protein levels were monitored in Pb-exposed rats. Pb exposure resulted in an induction of Sp1 DNA-binding during PND 5-10 followed by a subsequent decline on PND 15-20. The protein expression profiles for PKCalpha and MAPK followed a relatively similar pattern. To examine the interdependence between Sp1 DNA-binding, PKCalpha, and MAPK, PC12 cells were exposed to Pb and/or NGF. Pb or NGF exposure increased Sp1 DNA-binding. Addition of the PKC inhibitor (staurosporine) diminished NGF and Pb-induced Sp1 DNA-binding, while the MAPK inhibitor (PD 98059), completely abolished both basal and induced Sp1 DNA-binding. These findings demonstrate that Sp1 DNA-binding is regulated by PKC and MAPK, which may serve as mediators through which Pb may indirectly modulate Sp1 DNA-binding.
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Affiliation(s)
- D S Atkins
- Department of Pharmacology, Meharry Medical College, Nashville, TN 37028, USA
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47
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Abstract
Exposure to various chemicals and environmental hazards elicits changes in the expression of a variety of genes. The study of gene expression and transcriptional regulation is an important aspect of understanding the mechanisms associated with neurotoxicity. The availability of whole genome sequences and the development of new tools to identify and monitor transcriptional activity have accelerated the rate of discovery. This review surveys the historical steps taken to study gene expression in the brain and deals with recent advances in our understanding and classification of the roles of transcription factors. Disturbances in the regulation of gene expression associated with the neurotoxic response are also presented. Specific focus and detail is presented on the effects of heavy metals on the integrity and function of zinc finger proteins.
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Affiliation(s)
- Nasser H Zawia
- Department of Biomedical Sciences, University of Rhode Island, Kingston, RI 02881, USA.
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Basha MR, Wei W, Brydie M, Razmiafshari M, Zawia NH. Lead-induced developmental perturbations in hippocampal Sp1 DNA-binding are prevented by zinc supplementation: in vivo evidence for Pb and Zn competition. Int J Dev Neurosci 2003; 21:1-12. [PMID: 12565691 DOI: 10.1016/s0736-5748(02)00137-5] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Zinc finger protein (ZFP) transcription factors are essential for regulation of gene expression in the developing brain. We previously reported that Pb exposure perturbed the DNA-binding of ZFP such as Sp1 and Egr-1 in the cerebellum, which play critical role in CNS development. In this study, we focused on hippocampal Sp1 DNA-binding and mRNA expression in neonatal Pb-exposed animals. The expression pattern of an Sp1 target (NMDAR1) gene was also monitored. To study in vivo and in vitro competition between Pb and Zn, we supplemented animals with Zn, and examined the effects of both metals on hippocampal Sp1 DNA-binding and the DNA-binding of a recombinant Sp1 protein (rhSp1). Tissue metal analysis revealed that only the disposition of Pb in the brain but not its distribution in the blood was influenced by the presence of Zn. The developmental profile of Sp1 DNA-binding exhibited a peak on PND 15 which subsequently declined to adult levels. Consistent with earlier studies, Pb exposure produced premature peaks of Sp1 DNA-binding on PND 5 which later returned to adult levels. The basal and Pb-induced developmental patterns of Sp1 mRNA departed from its DNA-binding profiles. However, the expression patterns of the NMDAR1 gene were relative to Sp1 DNA-binding. Supplementation with zinc provided a protective effect on Pb-induced changes in Sp1 DNA-binding. Moreover, Pb and Zn directly interfered with the DNA-binding of rhSp1 in vitro. These data suggest that Pb and Zn can compete both in vivo and in vitro at the zinc finger domain of Sp1 with a consequential effect on Sp1 DNA-binding, subsequent gene expression and brain development.
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Affiliation(s)
- Md Riyaz Basha
- Department of Biomedical Sciences, University of Rhode Island, Kingston, RI 02881, USA
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Lidsky TI, Schneider JS. Lead neurotoxicity in children: basic mechanisms and clinical correlates. Brain 2003; 126:5-19. [PMID: 12477693 DOI: 10.1093/brain/awg014] [Citation(s) in RCA: 621] [Impact Index Per Article: 29.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Lead has been recognized as a poison for millennia and has been the focus of public health regulation in much of the developed world for the better part of the past century. The nature of regulation has evolved in response to increasing information provided by vigorous scientific investigation of lead's effects. In recognition of the particular sensitivity of the developing brain to lead's pernicious effects, much of this legislation has been addressed to the prevention of childhood lead poisoning. The present review discusses the current state of knowledge concerning the effects of lead on the cognitive development of children. Addressed are the reasons for the child's exquisite sensitivity, the behavioural effects of lead, how these effects are best measured, and the long-term outlook for the poisoned child. Of particular importance are the accumulating data suggesting that there are toxicological effects with behavioural concomitants at exceedingly low levels of exposure. In addition, there is also evidence that certain genetic and environmental factors can increase the detrimental effects of lead on neural development, thereby rendering certain children more vulnerable to lead neurotoxicity. The public health implications of these findings are discussed.
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Affiliation(s)
- Theodore I Lidsky
- Center for Trace Element Studies and Environmental Neurotoxicology, NYS Institute for Basic Research in Developmental Disabilities, Staten Island, NY 10314, USA.
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50
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Abstract
In the United States, between 40 and 90 million hospital days are lost per year as a result of trauma and surgical procedures which result in the loss of functional tissue. This is estimated to cost the economy and healthcare providers in excess of US$ 500 billion, a figure that is increasing because of extending population lifespan. Tissue engineering and gene therapies are radical new treatments that are aimed at tissue regeneration ranging from dermal, osteal and occular repair to the replacement of failing tissue with entire biosynthetic organs. Over the last decade, numerous proteins have been identified that are able to direct the synthesis of new tissue. Such proteins include growth factors, cytokines and, more recently, transcription factors.
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Affiliation(s)
- M Braddock
- Disease Cell Biology Unit, GlaxoWellcome Medicines Research Centre, Stevenage, Herts, UK.
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