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Zhang X, Zhang L, Yu T, Gao Y, Zhai T, Zhao T, Xing Z. Genetic response analysis of Beauveria bassiana Z1 under high concentration Cd(II) stress. JOURNAL OF HAZARDOUS MATERIALS 2024; 464:132984. [PMID: 37995637 DOI: 10.1016/j.jhazmat.2023.132984] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2023] [Revised: 10/27/2023] [Accepted: 11/08/2023] [Indexed: 11/25/2023]
Abstract
Cadmium (Cd(II)) has carcinogenic and teratogenic toxicity, which can be accumulated in the human body through the food chain, endangering human health and life. In this study, a highly Cd(II)-tolerant fungus named Beauveria bassiana Z1 was studied, and its Cd(Ⅱ) removal efficiency was 71.2% when the Cd(II) concentration was 10 mM. Through bioanalysis and experimental verification of the transcriptome data, it was found that cadmium entered the cells through calcium ion channels, and then complexed with intracellular glutathione (GSH) and stored in vacuoles or excluded extracellular by ABC transporters. Cytochrome P450 was significantly upregulated in many pathways and actively participated in detoxification related reactions. The addition of cytochrome inhibitor taxifolin reduced the removal efficiency of Cd(II) by 45%. In the analysis, it demonstrated that ACOX1 gene and OPR gene of jasmonic acid (JA) synthesis pathway were significantly up-regulated, and were correlated with bZIP family transcription factors cpc-1_0 and pa p1_0. The results showed that exogenous JA could improve the removal efficiency of Cd(II) by strain Z1.
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Affiliation(s)
- Xiaoping Zhang
- School of Chemistry and Chemical Engineering, Chongqing University of Technology, Chongqing 400054, China
| | - Lijie Zhang
- School of Pharmacy and Bioengineering, Chongqing University of Technology, Chongqing 400054, China.
| | - Tiantian Yu
- School of Pharmacy and Bioengineering, Chongqing University of Technology, Chongqing 400054, China
| | - Yanhui Gao
- School of Chemistry and Chemical Engineering, Chongqing University of Technology, Chongqing 400054, China
| | - Tianrui Zhai
- School of Chemistry and Chemical Engineering, Chongqing University of Technology, Chongqing 400054, China
| | - Tiantao Zhao
- School of Chemistry and Chemical Engineering, Chongqing University of Technology, Chongqing 400054, China
| | - Zhilin Xing
- School of Chemistry and Chemical Engineering, Chongqing University of Technology, Chongqing 400054, China
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2
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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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3
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Carmona A, Roudeau S, Ortega R. Molecular Mechanisms of Environmental Metal Neurotoxicity: A Focus on the Interactions of Metals with Synapse Structure and Function. TOXICS 2021; 9:toxics9090198. [PMID: 34564349 PMCID: PMC8471991 DOI: 10.3390/toxics9090198] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 08/25/2021] [Accepted: 08/25/2021] [Indexed: 02/07/2023]
Abstract
Environmental exposure to neurotoxic metals and metalloids such as arsenic, cadmium, lead, mercury, or manganese is a global health concern affecting millions of people worldwide. Depending on the period of exposure over a lifetime, environmental metals can alter neurodevelopment, neurobehavior, and cognition and cause neurodegeneration. There is increasing evidence linking environmental exposure to metal contaminants to the etiology of neurological diseases in early life (e.g., autism spectrum disorder) or late life (e.g., Alzheimer’s disease). The known main molecular mechanisms of metal-induced toxicity in cells are the generation of reactive oxygen species, the interaction with sulfhydryl chemical groups in proteins (e.g., cysteine), and the competition of toxic metals with binding sites of essential metals (e.g., Fe, Cu, Zn). In neurons, these molecular interactions can alter the functions of neurotransmitter receptors, the cytoskeleton and scaffolding synaptic proteins, thereby disrupting synaptic structure and function. Loss of synaptic connectivity may precede more drastic alterations such as neurodegeneration. In this article, we will review the molecular mechanisms of metal-induced synaptic neurotoxicity.
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Ortiz-Robles CD, Cortés-Montoya V, Reyes-Aguilar SS, Albores A, Calderón-Aranda ES. Low concentrations of lead disturb phenotypical markers of the inflammatory and the anti-inflammatory profile of bone marrow-derived macrophages from BALB/c mice. Toxicology 2021; 460:152885. [PMID: 34352350 DOI: 10.1016/j.tox.2021.152885] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 07/21/2021] [Accepted: 07/31/2021] [Indexed: 11/28/2022]
Abstract
Lead (Pb) is a ubiquitous toxic metal that decreases resistance to infections, in which the macrophages have an essential role. Pb adverse effects on nitric oxide (NO-) production and variable effects on inflammatory cytokines in activated macrophages have been reported, but no effects have been reported in anti-inflammatory macrophages. We studied Pb (0.03-6 μg/dL equivalent to 0.014-2.89 μM) effects on the function of bone marrow-derived macrophages (BMDM) induced to either inflammatory or anti-inflammatory phenotypes, with LPS + IFNγ or IL-4+IL-13, respectively, and whether these effects are related. Pb did not induce cytotoxicity at any concentration in both macrophage phenotypes. In inflammatory BMDM, Pb (6 μg/dL) inhibited NO- production without affecting inducible nitric oxide synthase (iNOS) levels or basal arginase activity. At 3 and 6 μg/dL, Pb enhanced the major histocompatibility complex class II (MHC II) membrane expression but did not modify CD86 expression, TNFα, or IL-1β production and secretion. In anti-inflammatory BMDM, Pb did not alter arginase activity, but at 3 and 6 μg/dL, increased TGF-β1 and mannose receptor expression. Results showed that environmentally relevant concentrations of Pb alter functional outcomes or phenotypic markers of anti-inflammatory for the first time. The Pb effects on the inflammatory macrophages are not dependent on negative feedback resulting from the Pb effect on the anti-inflammatory phenotype. The Pb affected only some molecules or specific pathways related to both phenotypes. These effects could be related to Pb effects on immune defense against intracellular pathogens and allergy susceptibility.
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Affiliation(s)
- Christian D Ortiz-Robles
- Departamento de Toxicología, Centro de Investigación y de Estudios Avanzados, Cinvestav del IPN, Ciudad de México, Mexico
| | - Vanessa Cortés-Montoya
- Departamento de Toxicología, Centro de Investigación y de Estudios Avanzados, Cinvestav del IPN, Ciudad de México, Mexico
| | - Sandra S Reyes-Aguilar
- Departamento de Toxicología, Centro de Investigación y de Estudios Avanzados, Cinvestav del IPN, Ciudad de México, Mexico
| | - Arnulfo Albores
- Departamento de Toxicología, Centro de Investigación y de Estudios Avanzados, Cinvestav del IPN, Ciudad de México, Mexico
| | - Emma S Calderón-Aranda
- Departamento de Toxicología, Centro de Investigación y de Estudios Avanzados, Cinvestav del IPN, Ciudad de México, Mexico.
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5
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Evaluation of Analytes Characterized with Potential Protective Action after Rat Exposure to Lead. Molecules 2021; 26:molecules26082163. [PMID: 33918725 PMCID: PMC8069014 DOI: 10.3390/molecules26082163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 04/07/2021] [Accepted: 04/08/2021] [Indexed: 11/17/2022] Open
Abstract
Lead (Pb) was revealed for its role as a neurodevelopmental toxin. The determination of neurotransmitters (NTs) in particular brain regions could ameliorate the precise description and optimization of therapeutic protocols able to restore the harmony of signaling pathways in nervous and immune systems. The determination of selected analytes from the group of NTs based on the liquid chromatography (LC)-based method was carried out to illustrate the changes of amino acid (AA) and biogenic amine (BA) profiles observed in chosen immune and nervous systems rat tissues after Pb intoxication. Also, a protective combination of AA was proposed to correct the changes caused by Pb intoxication. After the administration of Pb, changes were observed in all organs studied and were characterized by a fluctuation of NT concentrations in immune and nervous systems (hypothalamus samples). Using a protective mixture of bioactive compounds prevented numerous changes in the balance of NT. The combined analysis of the immune and nervous system while the normalizing effect of curative agents on the level of differentially secreted NTs and AA is studied could present a new approach to the harmonization of those two essential systems after Pb intoxication.
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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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Narayanan SE, Rehuman NA, Harilal S, Vincent A, Rajamma RG, Behl T, Uddin MS, Ashraf GM, Mathew B. Molecular mechanism of zinc neurotoxicity in Alzheimer's disease. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2020; 27:43542-43552. [PMID: 32909132 DOI: 10.1007/s11356-020-10477-w] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Accepted: 08/10/2020] [Indexed: 06/11/2023]
Abstract
Zinc (Zn) is an essential trace element for most organisms, including human beings. It plays a crucial role in several physiological processes such as catalytic reaction of enzymes, cellular growth, differentiation and metabolism, intracellular signaling, and modulation of nucleic acid structure. Zn containing above 50 metalloenzymes is responsible for proteins, receptors, and hormones synthesis and has a critical role in neurodevelopment. Zn also regulates excitatory and inhibitory neurotransmitters such as glutamate and GABA and is found in high concentration in the synaptic terminals of hippocampal mossy fibers that maintains cognitive function. It regulates LTP and LTD by regulation of AMPA and NMDA receptors. But an excess or deficiency of Zn becomes neurotoxic or cause impairment in growth or sexual maturation. There is mounting evidence that supports this idea of Zn becoming neurotoxic and being involved in the pathogenesis of AD. Zn dyshomeostasis in AD is an area that needs attention as moderate concentration of Zn is involved in the memory regulation via regulation of amyloid plaque. Dyshomeostasis of Zn is involved in the pathogenesis of diseases like AD, ALS, depression, PD, and schizophrenia.
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Affiliation(s)
- Siju Ellickal Narayanan
- P.G. Department of Pharmacology, College of Pharmaceutical Sciences, Govt. Medical College, Kannur, 670503, India
| | - Nisha Abdul Rehuman
- Department of Pharmaceutical Chemistry, Dr. Joseph Mar Thoma Institute of Pharmaceutical Sciences & Research, Kayamkulam, Kerala, 690503, India
| | - Seetha Harilal
- Department of Pharmacy, Kerala University of Health Sciences, Thrissur, Kerala, India
| | - Anju Vincent
- P.G. Department of Pharmacology, College of Pharmaceutical Sciences, Govt. Medical College, Kannur, 670503, India
| | | | - Tapan Behl
- Department of Pharmacology, Chitkara College of Pharmacy, Chitkara University, Rajpura, Punjab, India
| | - Md Sahab Uddin
- Department of Pharmacy, Southeast University, Dhaka, Bangladesh
- Pharmakon Neuroscience Research Network, Dhaka, Bangladesh
| | - Ghulam Md Ashraf
- King Fahd Medical Research Center, King Abdulaziz University, Jeddah, Saudi Arabia.
- Department of Medical Laboratory Technology, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah, Saudi Arabia.
| | - Bijo Mathew
- Division of Drug Design and Medicinal Chemistry Research Lab, Department of Pharmaceutical Chemistry, Ahalia School of Pharmacy, Palakkad, Kerala, 678557, India.
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8
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Nong Q, Chen X, Hu L, Huang Y, Luan T, Liu H, Chen B. Identification and characterization of Gd-binding proteins in NIH-3T3 cells. Talanta 2020; 219:121281. [DOI: 10.1016/j.talanta.2020.121281] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 06/03/2020] [Accepted: 06/06/2020] [Indexed: 11/30/2022]
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9
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Wang R, Zhang L, Chen Y, Zhang S, Zhuang T, Wang L, Xu M, Zhang N, Liu S. Elevated non-essential metals and the disordered metabolism of essential metals are associated to abnormal pregnancy with spontaneous abortion. ENVIRONMENT INTERNATIONAL 2020; 144:106061. [PMID: 32890886 DOI: 10.1016/j.envint.2020.106061] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 08/10/2020] [Accepted: 08/17/2020] [Indexed: 06/11/2023]
Abstract
Spontaneous abortion is a considerable threat to the physiology and mental health of the mother. The etiology of spontaneous abortion is multifactorial with complicated mechanisms, of which overexposure to non-essential metals (especially heavy metals) has been proposed to be associated with adverse birth outcomes. However, significant knowledge gaps remain to be filled in, such as the deleterious profile of non-essential metals and their interplay with essential metals in abnormal pregnancy. Under this setting, we aimed to address these challenges by conducting a cross-sectional study on 56 patients with spontaneous abortion in the 1st trimester, by comparing to 55 healthy pregnant women in 1st the trimester and 41 non-pregnant healthy women. Overexposure to a few non-essential metals, such as arsenic (As), antimony (Sb) and bismuth (Bi), was found in patients with spontaneous abortion, and likewise, some essential elements, such as magnesium (Mg), copper (Cu), vanadium (V), strontium (Sr) and tin (Sn), were also found to be elevated under spontaneous abortion. Further evidence of abnormal pregnancy was induced by a reduced level of internal hormones necessary for normal gestation, such as estradiol (E2) and progesterone (PRGE) in women with spontaneous abortion. Lactate dehydrogenase (LDH) and thyroid-stimulating hormone (TSH) levels were slightly increased in patients with spontaneous abortion. Comprehensive correlation analyses were carried out to identify the crucial factors that result in abortion. Our data stratified the important variables in decreasing order: PRGE, As, Mg, Sb, Sr, Sn, Bi and pregnant times in the progress of spontaneous abortion. Moreover, labyrinthine associations were uncovered between PRGE, non-essential metals and essential elements in causing spontaneous abortion. Therefore, our combined data unveiled the likely synergistic implications of elevated non-essential metals and the disordered metabolism of essential metals in abnormal pregnancy.
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Affiliation(s)
- Ruixia Wang
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Beijing, China
| | - Le Zhang
- Department of Medical Epidemiology and Biostatistics, Karolinska Institute, Stockholm, Sweden
| | - Yongjiu Chen
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Beijing, China
| | - Shuping Zhang
- The First Affiliated Hospital of Shandong First Medical University, Jinan, China
| | - Taifeng Zhuang
- Department of Neonatal Intensive Care Unit (NICU), Beijing Obstetrics and Gynecology Hospital, Capital Medical University, Beijing, China
| | - Li Wang
- Department of Ultrasound, Beijing Obstetrics and Gynecology Hospital, Capital Medical University, Beijing, China
| | - Ming Xu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Beijing, China
| | - Na Zhang
- Department of Ultrasound, Beijing Obstetrics and Gynecology Hospital, Capital Medical University, Beijing, China.
| | - Sijin Liu
- State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, China; University of Chinese Academy of Sciences, Beijing, China.
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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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11
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Gao Q, Dai Z, Zhang S, Fang Y, Yung KKL, Lo PK, Lai KWC. Interaction of Sp1 and APP promoter elucidates a mechanism for Pb 2+ caused neurodegeneration. Arch Biochem Biophys 2020; 681:108265. [PMID: 31945313 DOI: 10.1016/j.abb.2020.108265] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 01/10/2020] [Accepted: 01/12/2020] [Indexed: 12/31/2022]
Abstract
A ubiquitously expressed transcription factor, specificity protein 1 (Sp1), interacts with the amyloid precursor protein (APP) promoter and likely mediates APP expression. Promoter-interaction strengths variably regulate the level of APP expression. Here, we examined the interactions of finger 3 of Sp1 (Sp1-f3) with a DNA fragment containing the APP promoter in different ionic solutions using atomic force microscope (AFM) spectroscopy. Sp1-f3 molecules immobilized on an Si substrate were bound to the APP promoter, which was linked to the AFM tips via covalent bonds. The interactions were strongly influenced by Pb2+, considering that substituting Zn2+ with Pb2+ increased the binding affinity of Sp1 for the APP promoter. The results revealed that the enhanced interaction force facilitated APP expression and that APP overexpression could confer a high-risk for disease incidence. An increased interaction force between Sp1-f3 and the APP promoter in Pb2+ solutions was consistent with a lower binding free energy, as determined by computer-assisted analysis. The impact of Pb2+ on cell morphology and related mechanical properties were also detected by AFM. The overexpression of APP caused by the enhanced interaction force triggered actin reorganization and further resulted in an increased Young's modulus and viscosity. The correlation with single-force measurements revealed that altered cellular activities could result from alternation of Sp1-APP promoter interaction. Our AFM findings offer a new approach in understanding Pb2+ associated neurodegeneration.
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Affiliation(s)
- Qi Gao
- Department of Biomedical Engineering, Centre for Robotics and Automation, City University of Hong Kong, Kowloon, Hong Kong SAR, China
| | - Ziwen Dai
- Department of Chemistry, City University of Hong Kong, Kowloon, Hong Kong SAR, China; Key Laboratory of Biochip Technology, Biotech and Health Centre, Shenzhen Research Institute of City University of Hong Kong, Shenzhen, 518057, China
| | - Shiqing Zhang
- Department of Biology, Hong Kong Baptist University, Kowloon, Hong Kong SAR, China
| | - Yuqiang Fang
- School of Mechanical Science and Engineering, Jilin University, Changchun, 130025, China
| | - Ken Kin Lam Yung
- Department of Biology, Hong Kong Baptist University, Kowloon, Hong Kong SAR, China.
| | - Pik Kwan Lo
- Department of Chemistry, City University of Hong Kong, Kowloon, Hong Kong SAR, China; Key Laboratory of Biochip Technology, Biotech and Health Centre, Shenzhen Research Institute of City University of Hong Kong, Shenzhen, 518057, China.
| | - King Wai Chiu Lai
- Department of Biomedical Engineering, Centre for Robotics and Automation, City University of Hong Kong, Kowloon, Hong Kong SAR, China.
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12
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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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13
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Alekseenko SI, Skalny AV, Ajsuvakova OP, Skalnaya MG, Notova SV, Tinkov AA. Mucociliary transport as a link between chronic rhinosinusitis and trace element dysbalance. Med Hypotheses 2019; 127:5-10. [PMID: 31088648 DOI: 10.1016/j.mehy.2019.03.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Revised: 03/01/2019] [Accepted: 03/20/2019] [Indexed: 12/21/2022]
Abstract
Chronis rhinosinusitis is considered as a widespread public health issue with a prevalence of 10%. The disease significantly reduces quality of life and increases the risk of cardiovascular diseases as well as certain forms of cancer. Alteration of mucociliary clearance frequently observed in the patients and plays a significant role in disease pathogenesis. Certain studies have demonstrated that patients with chronic rhinosinusitis are characterized by significant reduction of essential trace elements and toxic metal overload. However, the particular mechanisms of the role of trace element dysbalance in chronic rhinosinusitis are unclear. We hypothesize that exposure to toxic trace elements (arsenic, nickel, cadmium) damages ciliary mucosal epithelium thus affecting mucociliary transport. In turn, altered mucociliary transport results in reduced removal of the inhaled metal-containing particles from nasal mucosa leading to their absorption and further aggravation of toxicity. Essential trace elements (zinc, selenium) play a significant role in regulation of mucociliary transport and immunity, thus their deficiency (either dietary or due to antagonism with toxic metals) may be associated with impaired functions and increased toxic metal toxicity. Therefore, a vicious circle involving metal accumulation and toxicity, essential element deficiency, impairment of mucociliary transport and metal particle removal, resulting in further accumulation of metals and aggravation of toxic effects is formed. The present hypothesis is supported by the findings on the impact of trace elements especially zinc and arsenic on mucociliary clearance, the role of mucociliary transport in heavy metal particles elimination from the airways, trace element dysbalance in chronic rhinosinusitis, as well as toxic and essential metal antagonism. The data from hypothesis testing and its verification may be used for development of therapeutic approach for management of chronic rhinosinusitis. Particularly, the use of essential elements (zinc, selenium) may reduce toxic metal toxicity thus destroying the vicious circle of heavy metal exposure, toxicity, alteration of mucociliary clearance, and aggravation of chronic rhinosinusitis. Essential element supplementation may be considered as a tool for management of chronic refractory rhinosinusitis. In addition, analysis of essential and toxic trace element status may provide an additional diagnostic approach to risk assessment of chronic rhinosinusitis in highly polluted environments.
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Affiliation(s)
- Svetlana I Alekseenko
- K. A. Raukhfuss Children's Municipal Multidisciplinary Clinical Center of High Medical Technologies, St. Petersburg, Russia; Mechnikov North-West State Medical University, St Petersburg, Russia
| | - Anatoly V Skalny
- Yaroslavl State University, Yaroslavl, Russia; Peoples' Friendship University of Russia (RUDN University), Moscow, Russia; I.M. Sechenov First Moscow State Medical University, Moscow, Russia
| | - Olga P Ajsuvakova
- Yaroslavl State University, Yaroslavl, Russia; Peoples' Friendship University of Russia (RUDN University), Moscow, Russia; I.M. Sechenov First Moscow State Medical University, Moscow, Russia
| | - Margarita G Skalnaya
- Peoples' Friendship University of Russia (RUDN University), Moscow, Russia; I.M. Sechenov First Moscow State Medical University, Moscow, Russia
| | - Svetlana V Notova
- Federal Research Centre of Biological Systems and Agro-technologies of the Russian Academy of Sciences, Orenburg, Russia; Orenburg State University, Orenburg, Russia
| | - Alexey A Tinkov
- Yaroslavl State University, Yaroslavl, Russia; Peoples' Friendship University of Russia (RUDN University), Moscow, Russia; I.M. Sechenov First Moscow State Medical University, Moscow, Russia.
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14
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Vašková J, Krempaská K, Žatko D, Mudroň P, Glinská G, Vaško L. Effects of Humic Acids in Chronic Lead Poisoning. Biol Trace Elem Res 2019; 187:230-242. [PMID: 29748928 DOI: 10.1007/s12011-018-1375-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Accepted: 05/02/2018] [Indexed: 10/16/2022]
Abstract
Chronic exposure to lead causes disruption to energy production mechanisms and tissue damage, in particular through its binding to thiol groups and competition for zinc binding sites. We investigated the possibility of preventing the consequences of chronic lead poisoning by administration of three different doses of humic acids (HAs) into feed with the aim of establishing an effective HA dose. During the 10-week experiment, a sub-lethal dose of lead acetate was given to rats during the first 5 weeks, with continuous administration of HA over 10 weeks. Measurements were taken to determine the content of the metals Pb, Mn, Cu, Fe and Zn; the metalloid Se; and selected antioxidant markers in the heart, liver, kidney and plasma after the first, fifth and tenth weeks of experiment. The administration of lead and HAs clearly affects the redistribution of the elements and the activity of the antioxidant enzymes. This fact was particularly highlighted in the lead-only group as, within the experiment, significantly higher Pb concentrations were found only in the plasma of this group. However, in the group with 1% HA administered with lead, we observed a rise in Zn concentrations in the organs and the deposition of Fe into the liver. Decreased glutathione reductase activity in the plasma and balanced reduced glutathione concentrations indicated sufficient efficiency of redox reactions. SOD activities were among those affected most strongly, with only the 1% HA group showing no effect on heavy metal redistribution as a result of HA administration.
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Affiliation(s)
- Janka Vašková
- Department of Medical and Clinical Biochemistry, Faculty of Medicine, Pavol Jozef Šafárik University in Košice, Tr. SNP 1, 040 66, Košice, Slovak Republic.
| | - Klára Krempaská
- Department of Medical and Clinical Biochemistry, Faculty of Medicine, Pavol Jozef Šafárik University in Košice, Tr. SNP 1, 040 66, Košice, Slovak Republic
| | - Daniel Žatko
- Department of Medical and Clinical Biochemistry, Faculty of Medicine, Pavol Jozef Šafárik University in Košice, Tr. SNP 1, 040 66, Košice, Slovak Republic
| | - Pavol Mudroň
- Clinic for Ruminants, University of Veterinary Medicine and Pharmacy in Košice, Komenského 73, 041 81, Košice, Slovak Republic
| | - Gabriela Glinská
- Department of Medical and Clinical Biochemistry, Faculty of Medicine, Pavol Jozef Šafárik University in Košice, Tr. SNP 1, 040 66, Košice, Slovak Republic
| | - Ladislav Vaško
- Department of Medical and Clinical Biochemistry, Faculty of Medicine, Pavol Jozef Šafárik University in Košice, Tr. SNP 1, 040 66, Košice, Slovak Republic
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15
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Abstract
Zinc ion binding is a principal event in the achievement of the correct fold in classical zinc finger domains since the motif is largely unfolded in the absence of metal. In the case of a prokaryotic zinc finger, the larger βββαα domain contributes to the folding mechanism with a larger hydrophobic core. For these reasons, following the great amount of attention devoted to unveiling the effect of xenobiotic metal ion replacement in zinc fingers and in zinc-containing proteins in general, the prokaryotic zinc finger domain appears to be an interesting model for studying metal ion interaction with metalloproteins. Here, we explore the binding of Ni(II), Hg(II), and Pb(II) to Ros87, the DNA binding domain of the prokaryotic zinc finger protein Ros. We measured Ros87-metal ion dissociation constants and monitored the effects on the structure and function of the domain. Interestingly, we found that the protein folds in the presence of Ni(II) with important structural perturbations, while in the presence of Pb(II) and Hg(II) it does not appear to be significantly folded. Accordingly, an overall strong reduction in the DNA binding capability is observed for all of the examined proteins. Our data integrate and complement the information collected in the past few years concerning the functional and structural effects of metal ion substitution in classical zinc fingers in order to contribute to a better comprehension of the toxicity of these metals in biological systems.
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16
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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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17
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Sobolewski M, Conrad K, Marvin E, Allen JL, Cory-Slechta DA. Endocrine active metals, prenatal stress and enhanced neurobehavioral disruption. Horm Behav 2018; 101:36-49. [PMID: 29355495 PMCID: PMC5970043 DOI: 10.1016/j.yhbeh.2018.01.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Revised: 01/05/2018] [Accepted: 01/14/2018] [Indexed: 11/24/2022]
Abstract
Metals, including lead (Pb), methylmercury (MeHg) and arsenic (As), are long-known developmental neurotoxicants. More recently, environmental context has been recognized to modulate metals toxicity, including nutritional state and stress exposure. Modulation of metal toxicity by stress exposure can occur through shared targeting of endocrine systems, such as the hypothalamic-pituitary-adrenal axis (HPA). Our previous rodent research has identified that prenatal stress (PS) modulates neurotoxicity of two endocrine active metals (EAMs), Pb and MeHg, by altering HPA and CNS systems disrupting behavior. Here, we review this research and further test the hypothesis that prenatal stress modulates metals neurotoxicity by expanding to test the effect of developmental As ± PS exposure. Serum corticosterone and behavior was assessed in offspring of dams exposed to As ± PS. PS increased female offspring serum corticosterone at birth, while developmental As exposure decreased adult serum corticosterone in both sexes. As + PS induced reductions in locomotor activity in females and reduced response rates on a Fixed Interval schedule of reinforcement in males, with the latter suggesting unique learning deficits only in the combined exposure. As-exposed males showed increased time in the open arms of an elevated plus maze and decreased novel object recognition whereas females did not. These data further confirm the hypothesis that combined exposure to chemical (EAMs) and non-chemical (PS) stressors results in enhanced neurobehavioral toxicity. Given that humans are exposed to multiple environmental risk factors that alter endocrine function in development, such models are critical for risk assessment and public health protection, particularly for children.
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Affiliation(s)
- Marissa Sobolewski
- Dept. of Environmental Medicine, University of Rochester School of Medicine, Rochester, NY, United States. marissa:
| | - Katherine Conrad
- Dept. of Environmental Medicine, University of Rochester School of Medicine, Rochester, NY, United States
| | - Elena Marvin
- Dept. of Environmental Medicine, University of Rochester School of Medicine, Rochester, NY, United States
| | - Joshua L Allen
- Dept. of Environmental Medicine, University of Rochester School of Medicine, Rochester, NY, United States
| | - Deborah A Cory-Slechta
- Dept. of Environmental Medicine, University of Rochester School of Medicine, Rochester, NY, United States
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18
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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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19
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Rahman A, Khan KM, Rao MS. Exposure to low level of lead during preweaning period increases metallothionein-3 expression and dysregulates divalent cation levels in the brain of young rats. Neurotoxicology 2018; 65:135-143. [PMID: 29452138 DOI: 10.1016/j.neuro.2018.02.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Revised: 02/11/2018] [Accepted: 02/12/2018] [Indexed: 12/11/2022]
Abstract
Lead (Pb) is a neurotoxic heavy metal, but the mechanism of its neurotoxicity is not clearly understood. Expression of metallothioneins (MTs) is induced in response to heavy metal exposure as a protective mechanism against heavy metal toxicity. There are several isoforms of MTs (MT-1 to 4), of which MT-3 is the neuron specific isoform, which also has neurite growth inhibitory effects. Whereas, the induction of MT-1 and 2 in response to Pb has been reported, the effect of Pb on the expression of MT-3 in the brain has not been documented. This study aimed at investigating the effect of Pb exposure on the expression of MT-3 in the cerebrum and hippocampus. Wistar rat pups were exposed to Pb via their dams' drinking water (0.2% lead acetate in deionized water) from postnatal day (PND) 0 to 21 and directly via drinking water until PND30. Expression of MT-3 was measured by Western blot and quantitative RT-PCR. MT-3 localization was done by immunohistochemistry. Divalent metal ions were analysed by atomic absorption spectrophotometry. Levels of Pb in blood and cerebrum were significantly increased, while that of copper (Cu), zinc (Zn) and manganese (Mn) were significantly decreased in the Pb-exposed rats at both PND21 and PND30. MT-3 protein was significantly increased in the cerebrum (by 2.5-fold) and in hippocampus (1.4 to 3.2-fold) in both PND21 and PND30 Pb-exposed rats over controls. MT-3 gene expression also increased in the cerebrum (by 42%), and in the hippocampus (by 65% and 43% in the PND21 and PND30 rats, respectively), in the Pb-exposed rats over controls, but the increase was statistically significant (p < 0.05) only in the PND30 rats. Pb exposure significantly increased (p < 0.05) percentage of MT-3 immunoreactive cells in Cornu Ammonis and dentate gyrus regions in the PND21 rats, and in the Cornu Ammonis 1, dentate gyrus and cortex regions in the PND30 rats. Our data thus provide convincing evidence that exposure to low levels of Pb during preweaning period increases the expression of MT-3 in the brain of rats.
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Affiliation(s)
- Abdur Rahman
- Department of Food Science and Nutrition, College of Life Sciences, Kuwait University, Kuwait.
| | - Khalid M Khan
- Department of Anatomy, Faculty of Medicine, Kuwait University, Kuwait
| | - Muddanna S Rao
- Department of Anatomy, Faculty of Medicine, Kuwait University, Kuwait
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20
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Pedroso TF, Oliveira CS, Fonseca MM, Oliveira VA, Pereira ME. Effects of Zinc and N-Acetylcysteine in Damage Caused by Lead Exposure in Young Rats. Biol Trace Elem Res 2017; 180:275-284. [PMID: 28389902 DOI: 10.1007/s12011-017-1009-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2016] [Accepted: 03/31/2017] [Indexed: 12/22/2022]
Abstract
This study investigated the toxicity of rats exposed to lead acetate (AcPb) during the second phase of brain development (8-12 days postnatal) in hematological and cerebral parameters. Moreover, the preventive effect of zinc chloride (ZnCl2) and N-acetylcysteine (NAC) was investigated. Pups were injected subcutaneously with saline (0.9% NaCl solution), ZnCl2 (27 mg/kg/day), NAC (5 mg/kg/day) or ZnCl2 plus NAC for 5 days (3rd-7th postnatal days), and with saline (0.9% NaCl solution) or AcPb (7 mg/kg/day) in the five subsequent days (8th-12th postnatal days). Animals were sacrificed 21 days after the last AcPb exposure. Pups exposed to AcPb presented inhibition of blood porphobilinogen-synthase (PBG-synthase) activity without changes in hemoglobin content. ZnCl2 pre-exposure partially prevented PBG-synthase inhibition. Regarding neurotoxicity biomarkers, animals exposed to AcPb presented a decrease in cerebrum acetylcholinesterase (AChE) activity and an increase in Pb accumulation in blood and cerebrum. These changes were prevented by pre-treatment with ZnCl2, NAC, and ZnCl2 plus NAC. AcPb exposure caused no alteration in behavioral tasks. In short, results show that AcPb inhibited the activity of two important enzymatic biomarkers up to 21 days after the end of the exposure. Moreover, ZnCl2 and NAC prevented the alterations induced by AcPb.
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Affiliation(s)
- Taíse F Pedroso
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica Toxicológica, Universidade Federal de Santa Maria, Santa Maria, RS, 97105-900, Brazil
| | - Cláudia S Oliveira
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica Toxicológica, Universidade Federal de Santa Maria, Santa Maria, RS, 97105-900, Brazil
| | - Mariana M Fonseca
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica Toxicológica, Universidade Federal de Santa Maria, Santa Maria, RS, 97105-900, Brazil
| | - Vitor A Oliveira
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica Toxicológica, Universidade Federal de Santa Maria, Santa Maria, RS, 97105-900, Brazil
| | - Maria Ester Pereira
- Programa de Pós-Graduação em Ciências Biológicas: Bioquímica Toxicológica, Universidade Federal de Santa Maria, Santa Maria, RS, 97105-900, Brazil.
- Departamento de Bioquímica e Biologia Molecular, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, RS, 97105-900, Brazil.
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21
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French AD, Conway WC, Cañas-Carrell JE, Klein DM. Exposure, Effects and Absorption of Lead in American Woodcock (Scolopax minor): A Review. BULLETIN OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2017; 99:287-296. [PMID: 28710526 DOI: 10.1007/s00128-017-2137-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Accepted: 07/01/2017] [Indexed: 06/07/2023]
Abstract
Due to long term declines of American Woodcock (Scolopax minor) and widespread distribution of environmentally available lead (Pb) throughout their geographic range, it is important to assess if Pb exposure is a potential contributor to these declines. Woodcock are exposed to Pb through various environmental sources and are known to exhibit relatively high bone-Pb concentrations. Absorption of Pb by birds, and woodcock specifically, is not well understood. Some studies show that interactions among calcium, phosphorus, iron, zinc, and vitamin D levels may play an important role in Pb absorption. Therefore, when future Pb studies are performed for woodcock, and other birds, interactions among these elements should be considered. For example, these interactions are relevant in the acquisition and mobilization of calcium in female birds during egg development and shell calcification. These factors should be considered to understand potential mechanisms of Pb exposure, Pb absorption, and subsequent Pb toxicity to birds in general, and woodcock specifically. This review discusses Pb exposure routes, effects of Pb toxicity, and the distribution of Pb in American woodcock and identifies areas for future research in woodcock and other avian species.
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Affiliation(s)
- Amanda D French
- Department of Environmental Toxicology, The Institute of Environmental and Human Health, Texas Tech University, Lubbock, TX, 79416, USA
| | - Warren C Conway
- Department of Natural Resources Management, Texas Tech University, Lubbock, TX, 79409, USA
| | - Jaclyn E Cañas-Carrell
- Department of Environmental Toxicology, The Institute of Environmental and Human Health, Texas Tech University, Lubbock, TX, 79416, USA
| | - David M Klein
- Department of Environmental Toxicology, The Institute of Environmental and Human Health, Texas Tech University, Lubbock, TX, 79416, USA.
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22
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Andrade VM, Aschner M, Marreilha dos Santos AP. Neurotoxicity of Metal Mixtures. ADVANCES IN NEUROBIOLOGY 2017; 18:227-265. [DOI: 10.1007/978-3-319-60189-2_12] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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23
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Hubbs-Tait L, Nation JR, Krebs NF, Bellinger DC. Neurotoxicants, Micronutrients, and Social Environments. Psychol Sci Public Interest 2016; 6:57-121. [DOI: 10.1111/j.1529-1006.2005.00024.x] [Citation(s) in RCA: 81] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
SUMMARY—Systematic research evaluating the separate and interacting impacts of neurotoxicants, micronutrients, and social environments on children's cognition and behavior has only recently been initiated. Years of extensive human epidemiologic and animal experimental research document the deleterious impact of lead and other metals on the nervous system. However, discrepancies among human studies and between animal and human studies underscore the importance of variations in child nutrition as well as social and behavioral aspects of children's environments that mitigate or exacerbate the effects of neurotoxicants. In this monograph, we review existing research on the impact of neurotoxic metals, nutrients, and social environments and interactions across the three domains. We examine the literature on lead, mercury, manganese, and cadmium in terms of dispersal, epidemiology, experimental animal studies, effects of social environments, and effects of nutrition. Research documenting the negative impact of lead on cognition and behavior influenced reductions by the Center for Disease Control in child lead-screening guidelines from 30 micrograms per deciliter (μg/dL) in 1975 to 25 μg/dL in 1985 and to 10 μg/dL in 1991. A further reduction is currently being considered. Experimental animal research documents lead's alteration of glutamate-neurotransmitter (particularly N-methyl-D-aspartate) activity vital to learning and memory. In addition, lead induces changes in cholinergic and dopaminergic activity. Elevated lead concentrations in the blood are more common among children living in poverty and there is some evidence that socioeconomic status influences associations between lead and child outcomes. Micronutrients that influence the effects of lead include iron and zinc. Research documenting the negative impact of mercury on children (as well as adults) has resulted in a reference dose (RfD) of 0.1 microgram per kilogram of body weight per day (μg/kg/day). In animal studies, mercury interferes with glutamatergic, cholinergic, and dopaminergic activity. Although evidence for interactions of mercury with children's social contexts is minimal, researchers are examining interactions of mercury with several nutrients. Research on the effects of cadmium and manganese on child cognition and behavior is just beginning. Experimental animal research links cadmium to learning deficits, manganese to behaviors characteristic of Parkinson's disease, and both to altered dopaminergic functioning. We close our review with a discussion of policy implications, and we recommend interdisciplinary research that will enable us to bridge gaps within and across domains.
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Affiliation(s)
- Laura Hubbs-Tait
- Department of Human Development and Family Science, Oklahoma State University
| | | | - Nancy F. Krebs
- Department of Pediatrics, University of Colorado School of Medicine
| | - David C. Bellinger
- Department of Neurology, Harvard Medical School; Department of Environmental Health, Harvard School of Public Health; and Children's Hospital Boston
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24
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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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25
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Basha CD, Reddy RG. Long-term changes in brain cholinergic system and behavior in rats following gestational exposure to lead: protective effect of calcium supplement. Interdiscip Toxicol 2015; 8:159-68. [PMID: 27486377 PMCID: PMC4961914 DOI: 10.1515/intox-2015-0025] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Revised: 12/12/2015] [Accepted: 12/17/2015] [Indexed: 11/15/2022] Open
Abstract
Our earlier studies showed that lactational exposure to lead (Pb) caused irreversible neurochemical alterations in rats. The present study was carried out to examine whether gestational exposure to Pb can cause long-term changes in the brain cholinergic system and behavior of rats. The protective effect of calcium (Ca) supplementation against Pb toxicity was also examined. Pregnant rats were exposed to 0.2% Pb (Pb acetate in drinking water) from gestational day (GD) 6 to GD 21. The results showed decrease in body weight gain (GD 6-21) of dams, whereas no changes were observed in offspring body weight at different postnatal days following Pb exposure. Male offspring treated with Pb showed marginal alterations in developmental landmarks such as unfolding of pinnae, lower and upper incisor eruption, fur development, eye slit formation and eye opening on postnatal day (PND) 1, whereas significant alterations were found in the righting reflex (PNDs 4-7), slant board behavior (PNDs 8-10) and forelimb hang performance (PNDs 12-16). Biochemical analysis showed decrease in synaptosomal acetylcholinesterase (AChE) activity and an increase in acetylcholine (ACh) levels in the cortex, cerebellum and hippocampus on PND 14, PND 21, PND 28 and in the four-month age group of rats following Pb exposure. Significant deficits were also observed in total locomotor activity, exploratory behavior and open field behavior in selected age groups of Pb-exposed rats. These alterations were found to be maximal on PND 28, corresponding with the greater blood lead levels observed on PND 28. Addition of 0.02% Ca to Pb reversed the Pb-induced impairments in the cholinergic system as well as in behavioral parameters of rats. In conclusion, these data suggest that gestational exposure to Pb is able to induce long-term changes in neurological functions of offspring. Maternal Ca administration reversed these neurological effects of Pb later in life, suggesting a protective effect of calcium in Pb-exposed animals.
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Affiliation(s)
- Chand D Basha
- Department of Zoology, Sri Venkateswara University, Tirupati - 517502, India
| | - Rajarami G Reddy
- Department of Zoology, Sri Venkateswara University, Tirupati - 517502, India
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26
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The role of Nrf2 in protection against Pb-induced oxidative stress and apoptosis in SH-SY5Y cells. Food Chem Toxicol 2015; 86:191-201. [PMID: 26498409 DOI: 10.1016/j.fct.2015.10.009] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Revised: 10/06/2015] [Accepted: 10/16/2015] [Indexed: 11/21/2022]
Abstract
Lead exerts severe adverse effects on the nervous system in which oxidative stress might mediate impairments. In this study, we focused on Nrf2, which has been identified to significantly influence the protection of a cellular system against many xenobiotic compounds. We found that PbAc exhibited neurotoxicity mainly through oxidant-based processes and could be inhibited by NAC and DPI in SH-SY5Y cells. As a defense response, Nrf2 was activated when exposed to PbAc, thereby inducing a rapid increase in Nrf2 nuclear accumulation, as well as Nrf2-ARE binding activities in a ROS-dependent manner. Analysis of Nrf2-regulated gene expression and protein showed that PbAc could induce the mRNA transcription of HO-1, GSTα1, GCLM, GCLC, and NQO1, as well as the protein expression of HO-1 and γ-GCS. The responses of these genes to PbAc were regulated by Nrf2. Silencing Nrf2 expression in SH-SY5Y cells inhibited PbAc-induced gene transcription and protein expression. Overexpression of Nrf2 led to decreased ROS production and cell apoptosis, as well as increased cell viability under PbAc exposure. These results indicated that the Nrf2-ARE system exhibited a protective role in Pb-induced neurotoxicity, providing potential therapeutic strategies for the prevention and treatment of Pb-related diseases.
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27
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Malgieri G, Palmieri M, Russo L, Fattorusso R, Pedone PV, Isernia C. The prokaryotic zinc-finger: structure, function and comparison with the eukaryotic counterpart. FEBS J 2015; 282:4480-96. [PMID: 26365095 DOI: 10.1111/febs.13503] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Revised: 07/23/2015] [Accepted: 08/24/2015] [Indexed: 01/18/2023]
Abstract
Classical zinc finger (ZF) domains were thought to be confined to the eukaryotic kingdom until the transcriptional regulator Ros protein was identified in Agrobacterium tumefaciens. The Ros Cys2 His2 ZF binds DNA in a peculiar mode and folds in a domain significantly larger than its eukaryotic counterpart consisting of 58 amino acids (the 9-66 region) arranged in a βββαα topology, and stabilized by a conserved, extensive, 15-residue hydrophobic core. The prokaryotic ZF domain, then, shows some intriguing new features that make it interestingly different from its eukaryotic counterpart. This review will focus on the prokaryotic ZFs, summarizing and discussing differences and analogies with the eukaryotic domains and providing important insights into their structure/function relationships.
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Affiliation(s)
- Gaetano Malgieri
- Department of Environmental, Biological and Pharmaceutical Science and Technology, II University of Naples, Caserta, Italy
| | - Maddalena Palmieri
- Department of Environmental, Biological and Pharmaceutical Science and Technology, II University of Naples, Caserta, Italy
| | - Luigi Russo
- Department of Environmental, Biological and Pharmaceutical Science and Technology, II University of Naples, Caserta, Italy
| | - Roberto Fattorusso
- Department of Environmental, Biological and Pharmaceutical Science and Technology, II University of Naples, Caserta, Italy.,Interuniversity Research Centre on Bioactive Peptides, University of Naples 'Federico II', Naples, Italy
| | - Paolo V Pedone
- Department of Environmental, Biological and Pharmaceutical Science and Technology, II University of Naples, Caserta, Italy.,Interuniversity Research Centre on Bioactive Peptides, University of Naples 'Federico II', Naples, Italy
| | - Carla Isernia
- Department of Environmental, Biological and Pharmaceutical Science and Technology, II University of Naples, Caserta, Italy.,Interuniversity Research Centre on Bioactive Peptides, University of Naples 'Federico II', Naples, Italy
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Karamian R, Komaki A, Salehi I, Tahmasebi L, Komaki H, Shahidi S, Sarihi A. Vitamin C reverses lead-induced deficits in hippocampal synaptic plasticity in rats. Brain Res Bull 2015; 116:7-15. [DOI: 10.1016/j.brainresbull.2015.05.004] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2014] [Revised: 04/11/2015] [Accepted: 05/08/2015] [Indexed: 12/11/2022]
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Malgieri G, Palmieri M, Esposito S, Maione V, Russo L, Baglivo I, de Paola I, Milardi D, Diana D, Zaccaro L, Pedone PV, Fattorusso R, Isernia C. Zinc to cadmium replacement in the prokaryotic zinc-finger domain. Metallomics 2014; 6:96-104. [PMID: 24287553 DOI: 10.1039/c3mt00208j] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Given the similar chemical properties of zinc and cadmium, zinc finger domains have been often proposed as mediators of the toxic and carcinogenic effects exerted by this xenobiotic metal. The effects of zinc replacement by cadmium in different eukaryotic zinc fingers have been reported. In the present work, to evaluate the effects of such substitution in the prokaryotic zinc finger, we report a detailed study of its functional and structural consequences on the Ros DNA binding domain (Ros87). We show that this protein, which bears important structural differences with respect to the eukaryotic domains, appears to structurally tolerate the zinc to cadmium substitution and the presence of cadmium does not affect the DNA binding activity of the protein. Moreover, we show for the first time how zinc to cadmium replacement can also take place in a cellular context. Our findings both complement and extend previous results obtained for different eukaryotic zinc fingers, suggesting that metal substitution in zinc fingers may be of relevance to the toxicity and/or carcinogenicity mechanisms of this metal.
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Affiliation(s)
- Gaetano Malgieri
- Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, Via Vivaldi 43, 81100 Caserta, Italy.
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Phyu MP, Tangpong J. Neuroprotective effects of xanthone derivative of Garcinia mangostana against lead-induced acetylcholinesterase dysfunction and cognitive impairment. Food Chem Toxicol 2014; 70:151-6. [PMID: 24795231 DOI: 10.1016/j.fct.2014.04.035] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Revised: 04/21/2014] [Accepted: 04/21/2014] [Indexed: 01/22/2023]
Abstract
Lead poisoning is a common environmental toxicity and low level of lead exposure is responsible for neurobehavioral or intelligence defects. This study was designed to investigate the protective effect of a xanthone derivative of Garcinia mangostana against lead-induced acetycholinesterase (AChE) dysfunction and cognitive impairment in mice. ICR mice were exposed to lead acetate (Pb) in drinking water (1%) with or without xanthone co-administration (100 and 200mg/kgBW/day) for 38days. Xanthone possesses a high phenolic content, which is positive correlation with its antioxidant activity (R(2)=0.98). The IC50 of xanthone on scavenging free radical activities, hydroxyl radical, superoxide radical, hydrogen peroxide and nitric oxide in cell-free system were 0.48±0.08, 1.88±0.09, 2.20±0.03 and 0.98±0.40mg/mL, respectively. We found that Pb induced AChE dysfunction and memory deficit in a dose dependent manner, indicated by in vitro and in vivo studies. However, xanthone significantly restored AChE activity in the blood and brains of mice and prevented Pb-induced neurobehavioral defect indicators with Forced Swimming and Morris water maze tests. Xanthone treatment improved all indicators compared to the Pb-treated group. In conclusion, xanthone alleviates Pb-induced neurotoxicity, in part, by suppression of oxidative damage and reversing AChE activity with a reduction in learning deficit and memory loss.
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Affiliation(s)
- Moe Pwint Phyu
- Biomedical Sciences, School of Allied Health Sciences and Public Health, Walailak University, Nakhon Si Thammarat 80160, Thailand
| | - Jitbanjong Tangpong
- Biomedical Sciences, School of Allied Health Sciences and Public Health, Walailak University, Nakhon Si Thammarat 80160, Thailand.
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31
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Ahmed MB, Ahmed MI, Meki AR, Abdraboh N. Neurotoxic effect of lead on rats: Relationship to Apoptosis. Int J Health Sci (Qassim) 2014; 7:192-9. [PMID: 24421747 DOI: 10.12816/0006042] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND Lead toxicity has been subjected to intensive research work, but some aspects of its mechanism needs to be elucidated. OBJECTIVES In the current study we aim to investigate the impact of lead toxicity on some different intermediates of apoptotic signaling pathway in experimental rats. DESIGN AND METHODS We measured caspase-8 and caspase-9 [by chemilumenescence], Bax and Bcl-2 [by ELISA] in Experimental rats, injected intraperitoneally with lead acetate for 7days at the dosage of 25, 50 and l00 mg/kg body weight and compared to control rats injected with deionized distilled water instead. instead. RESULTS Lead acetate significantly increased the levels of caspase 8, caspase 9 and Bax in liver, kidney and brain of experimental animals especially those with high doses. Meanwhile, caspase 8 and Bax significantly increased in brain tissue at low dose of lead, while Bcl-2 significantly increased only with advanced toxicity. Furthermore, Bax/bcl2 ratio was significantly high in kidney (p<0.05), liver (p<0.01) and brain (p<0.01) at higher doses of lead toxicity. However, brain tissues showed significant Bax/Bcl2 ratio (p<0.05) at low lead dose. A significant positive correlation was noticed between the blood level of lead and enzymatic level of caspase 8, caspase 9 and Bax in different tissues. CONCLUSION : we concluded that lead might have toxic effect through intrinsic and extrinsic induction of apoptotic pathway with prominent effect on brain tissue even at low dose.
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Affiliation(s)
| | - Maha Imam Ahmed
- Department of Medical Biochemistry, Faculty of Medicine, Qassim University, KSA
| | - Abd-Rheem Meki
- Department of Medical Biochemistry, Faculty of Medicine, Qassim University, KSA
| | - Naglaa Abdraboh
- Department of Medical Biochemistry, Faculty of Medicine, Ain Shams University Cairo, Egypt
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32
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Dosunmu R, Wu J, Basha MR, Zawia NH. Environmental and dietary risk factors in Alzheimer’s disease. Expert Rev Neurother 2014; 7:887-900. [PMID: 17610395 DOI: 10.1586/14737175.7.7.887] [Citation(s) in RCA: 75] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Alzheimer's disease (AD) is a progressive neurodegenerative disease that affects millions in the aging population worldwide and will affect millions more in the next 20 years. Over 90% of all cases are sporadic, with genetics playing a minor role in the etiology of AD. Therefore, it is crucial to investigate the environment and diet as primary risk factors in AD pathology. This review considers epidemiologic case control studies, and in vitro and in vivo research to investigate the potential of environmental exposure to metals, air pollution and pesticides as well as diet as risk factors for AD. In some cases, the role of genetic mutations and environmental risk is discussed. The evidence examined in this review provides a brief overview of the current literature on selected, significant risk factors in promoting amyloid-beta accumulation and aggregation, thus contributing to neurodegeneration.
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Affiliation(s)
- Remi Dosunmu
- University of Rhode Island, Department of Biomedical & Pharmaceutical Sciences, Kingston, RI 02881, USA.
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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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34
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Abdel Moneim AE. Flaxseed oil as a neuroprotective agent on lead acetate-induced monoamineric alterations and neurotoxicity in rats. Biol Trace Elem Res 2012; 148:363-70. [PMID: 22395955 DOI: 10.1007/s12011-012-9370-4] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2011] [Accepted: 02/20/2012] [Indexed: 11/28/2022]
Abstract
Lead remains a considerable occupational and public health problem, which is known to cause a number of adverse effects in both man and animals. Here, the neuroprotective effect of flaxseed oil (1,000 mg/kg) on lead acetate (20 mg/kg) induced alternation in monoamines and brain oxidative stress was examined in rats. The levels of lead, dopamine (DA), norepinephrine (NE), serotonin (5-HT), lipid peroxidation, nitrite/nitrate (NO), and glutathione (GSH) were determined; also, the activity of acetylcholinesterase (AChE) and Na(+)-K(+)-ATPase were estimated on different brain regions of adult male albino rats. The level of lead was markedly elevated in different brain regions of rats. This leads to enhancement of lipid peroxidation and NO production in brain with concomitant reduction in AChE activity and GSH level. In addition, the levels of DA, NE, and 5-HT were decreased in the brain. These findings were associated with BAX over expression. Treatment of rats with flaxseed oil induced a marked improvement in most of the studied parameters as well as the immunohistochemistry features. These data indicated that dietary flaxseed oil provide protection against lead-induced oxidative stress and neurotoxic effects.
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Affiliation(s)
- Ahmed E Abdel Moneim
- Instituto de Biotecnología, Centro de Investigación Biomédica, Parque Tecnológico de Ciencias de la Salud, Universidad de Granada, Granada, Spain.
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35
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Spirulina or dandelion-enriched diet of mothers alleviates lead-induced damages in brain and cerebellum of newborn rats. Food Chem Toxicol 2012; 50:2303-10. [DOI: 10.1016/j.fct.2012.04.003] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2011] [Revised: 03/29/2012] [Accepted: 04/02/2012] [Indexed: 11/23/2022]
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36
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Alashwal H, Dosunmu R, Zawia NH. Integration of genome-wide expression and methylation data: relevance to aging and Alzheimer's disease. Neurotoxicology 2012; 33:1450-1453. [PMID: 22743688 DOI: 10.1016/j.neuro.2012.06.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2012] [Revised: 05/24/2012] [Accepted: 06/17/2012] [Indexed: 11/27/2022]
Abstract
The progressive and latent nature of neurodegenerative diseases, such as Alzheimer's disease (AD) indicates the role of epigenetic modification in disease susceptibility. Previous studies from our lab show that developmental exposure to lead (Pb) perturbs the expression of AD-associated proteins. In order to better understand the role of DNA methylation as an epigenetic modifications mechanism in gene expression regulation, an integrative study of global gene expression and methylation profiles is essential. Given the different formats of gene expression and methylation data, combining these data for integrative analysis can be challenging. In this paper we describe a method to integrate and analyze gene expression and methylation arrays. Methylation array raw data contain the signal intensities of each probe of CpG sites, whereas gene expression data measure the signal intensity values of genes. In order to combine these data, methylation data of CpG sites have to be associated with genes.
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Affiliation(s)
- Hany Alashwal
- Department of Biomedical and Pharmaceutical Sciences, University of Rhode Island, Kingston, RI 02881, USA; Department of Math & Computer Science, Ibb University, P.O. Box 70270, Ibb, Yemen
| | - Remi Dosunmu
- Department of Biomedical and Pharmaceutical Sciences, University of Rhode Island, Kingston, RI 02881, USA
| | - Nasser H Zawia
- Department of Biomedical and Pharmaceutical Sciences, University of Rhode Island, Kingston, RI 02881, USA; Interdisciplinary Neuroscience Program, University of Rhode Island, Kingston, RI 02881, USA.
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37
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Genome-wide expression and methylation profiling in the aged rodent brain due to early-life Pb exposure and its relevance to aging. Mech Ageing Dev 2012; 133:435-43. [PMID: 22613225 DOI: 10.1016/j.mad.2012.05.003] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2011] [Revised: 04/28/2012] [Accepted: 05/05/2012] [Indexed: 11/23/2022]
Abstract
In this study, we assessed global gene expression patterns in adolescent mice exposed to lead (Pb) as infants and their aged siblings to identify reprogrammed genes. Global expression on postnatal day 20 and 700 was analyzed and genes that were down- and up-regulated (≥2 fold) were identified, clustered and analyzed for their relationship to DNA methylation. About 150 genes were differentially expressed in old age. In normal aging, we observed an up-regulation of genes related to the immune response, metal-binding, metabolism and transcription/transduction coupling. Prior exposure to Pb revealed a repression in these genes suggesting that disturbances in developmental stages of the brain compromise the ability to defend against age-related stressors, thus promoting the neurodegenerative process. Overexpression and repression of genes corresponded with their DNA methylation profile.
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38
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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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39
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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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40
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Waggas AM. Grape Seed Extract (<i>Vitisvinifera</i>) Alleviate Neurotoxicity and Hepatotoxicity Induced by Lead Acetate in Male Albino Rats. ACTA ACUST UNITED AC 2012. [DOI: 10.4236/jbbs.2012.22021] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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41
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Loef M, Mendoza LF, Walach H. Lead (Pb) and the Risk of Alzheimer’s disease or cognitive decline: A systematic review. TOXIN REV 2011. [DOI: 10.3109/15569543.2011.624664] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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42
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Huang H, Bihaqi SW, Cui L, Zawia NH. In vitro Pb exposure disturbs the balance between Aβ production and elimination: the role of AβPP and neprilysin. Neurotoxicology 2011; 32:300-6. [PMID: 21315759 PMCID: PMC3086455 DOI: 10.1016/j.neuro.2011.02.001] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2010] [Revised: 02/03/2011] [Accepted: 02/04/2011] [Indexed: 10/18/2022]
Abstract
Metabolism of β-amyloid peptide (Aβ) is closely associated with the pathology and etiology of Alzheimer's disease (AD). Our previous studies on aging primates and rodents have revealed that early life lead exposure increases the expression of the β-amyloid precursor protein (AβPP), elevates Aβ levels, and promotes neurodegeneration in old age. These effects were attributed to de novo synthetic pathways; however, the impact on Aβ degradation was not explored. Neprilysin (NEP), a rate-limiting catabolic peptidase is involved in Aβ metabolism in vivo. In the present study we sought to investigate whether accumulation of Aβ induced by Pb exposure is partially due to its ability to subdue NEP expression and consequently NEP activity. SH-SY5Y cells were exposed to Pb concentrations of 0, 5, 10, 20, and 50 μM for 48 h and AβPP, NEP protein and mRNA levels were measured. Additionally, NEP enzymatic activity and Aβ levels were also assessed. Western blot and RT-PCR analysis indicated significant increases in the protein and mRNA expression of AβPP, which appeared to be concentration and time-dependent, while the protein and mRNA expression of NEP as well as NEP activity declined. These actions of Pb were specific and were not observed when substituted by another metal. These results suggest that Pb causes both the overexpression of AβPP and repression of NEP resulting in the buildup of Aβ.
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Affiliation(s)
- Hui Huang
- Department of Biomedical & Pharmaceutical Sciences, University of Rhode Island, Kingston, RI, USA
- School of Public Health, Zhengzhou University, Zhengzhou, Henan, China, 450001
| | - Syed Waseem Bihaqi
- Department of Biomedical & Pharmaceutical Sciences, University of Rhode Island, Kingston, RI, USA
| | - Liuxin Cui
- School of Public Health, Zhengzhou University, Zhengzhou, Henan, China, 450001
| | - Nasser H. Zawia
- Department of Biomedical & Pharmaceutical Sciences, University of Rhode Island, Kingston, RI, USA
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43
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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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44
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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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45
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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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46
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Bokara KK, Blaylock I, Denise SB, Bettaiya R, Rajanna S, Yallapragada PR. Influence of lead acetate on glutathione and its related enzymes in different regions of rat brain. J Appl Toxicol 2010; 29:452-8. [PMID: 19263481 DOI: 10.1002/jat.1423] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
This study is intended to determine the effect of lead acetate on glutathione and its associated enzymes of rat brain. Wistar male rats were treated with lead acetate (500 ppm) through drinking water for a period of 8 weeks and parallel controls were maintained. They were sacrificed at the first, fourth and eighth week to isolate whole brains, which were separated into cerebellum, hippocampus, frontal cortex and brain stem. The data indicate enhanced (P < 0.05) glutathione peroxidase (G-Px) activity at most of the intervals for cerebellum, frontal cortex and brain stem, suggesting conversion of GSH to GSSG, while the hippocampus showed decreased levels. In contrast, glutathione reductase (GR) decreased significantly (P < 0.05) in cerebellum, frontal cortex and brain stem at all intervals except the fourth week in frontal cortex and brain stem. Hippocampus exhibited a gradual and significant (P < 0.05) increase in GR activity. Glutathione-S-transferase (GSTase) activity increased with exposure time in all four brain tissues, showing protection against lead acetate toxicity. The GSH and GSSG levels correlated well with the activities of GPx, GR and GSTase in all four regions of the brain. Overall the results indicate that lead acetate affects glutathione-related enzymes differentially and these changes can be attributed to differences in tissue susceptibility.
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47
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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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Prins JM, Park S, Lurie DI. Decreased expression of the voltage-dependent anion channel in differentiated PC-12 and SH-SY5Y cells following low-level Pb exposure. Toxicol Sci 2009; 113:169-76. [PMID: 19822599 DOI: 10.1093/toxsci/kfp249] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Lead (Pb) has been shown to disrupt cellular energy metabolism, which may underlie the learning deficits and cognitive dysfunctions associated with environmental Pb exposure. The voltage-dependent anion channel (VDAC) plays a central role in regulating energy metabolism in neurons by maintaining cellular ATP levels and regulating calcium buffering, and studies have shown that VDAC expression is associated with learning in mice. In this study, we examined the effect of 5 and 10microM Pb on VDAC expression in vitro in order to determine whether Pb alters VDAC expression levels in neuronal cell lines. PC-12 and SH-SY5Y cells were used since they differentiate to resemble primary neuronal cells. VDAC expression levels were significantly decreased 48 h after exposure to Pb in both cell lines. In contrast, exposure to 24 h of hypoxia failed to produce a decrease in VDAC, suggesting that decreased VDAC expression is not a general cellular stress response but is a result of Pb exposure. This decreased VDAC expression was also correlated with a corresponding decrease in cellular ATP levels. Real-time reverse transcription-polymerase chain reaction demonstrated a significant decrease in messenger RNA levels for the VDAC1 isoform, indicating that Pb reduces transcription of VDAC1. These results demonstrate that exposure to 5 and 10microM Pb reduces VDAC transcription and expression and is associated with reduced cellular ATP levels.
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Affiliation(s)
- John M Prins
- Center for Structural and Functional Neuroscience, The University of Montana, Missoula, Montana 59812, USA
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Behl M, Zhang Y, Zheng W. Involvement of insulin-degrading enzyme in the clearance of beta-amyloid at the blood-CSF barrier: Consequences of lead exposure. Cerebrospinal Fluid Res 2009; 6:11. [PMID: 19747378 PMCID: PMC2753621 DOI: 10.1186/1743-8454-6-11] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2009] [Accepted: 09/11/2009] [Indexed: 11/28/2022] Open
Abstract
Background Alzheimer's disease (AD) is characterized by the deposition of beta-amyloid (Aβ) peptides in the brain extracellular matrix, resulting in pathological changes and neurobehavioral deficits. Previous work from this laboratory demonstrated that the choroid plexus (CP) possesses the capacity to remove Aβ from the cerebrospinal fluid (CSF), and exposure to lead (Pb) compromises this function. Since metalloendopeptidase insulin-degrading enzyme (IDE), has been implicated in the metabolism of Aβ, we sought to investigate whether accumulation of Aβ following Pb exposure was due to the effect of Pb on IDE. Methods Rats were injected with a single dose of Pb acetate or an equivalent concentration of Na-acetate; CP tissues were processed to detect the location of IDE by immunohistochemistry. For in vitro studies, choroidal epithelial Z310 cells were treated with Pb for 24 h in the presence or absence of a known IDE inhibitor, N-ethylmaleimide (NEM) to assess IDE enzymatic activity and subsequent metabolic clearance of Aβ. Additionally, the expression of IDE mRNA and protein were determined using real time PCR and western blots respectively. Results Immunohistochemistry and confocal imaging revealed the presence of IDE towards the apical surface of the CP tissue with no visible alteration in either its intensity or location following Pb exposure. There was no significant difference in the expressions of either IDE mRNA or protein following Pb exposure compared to controls either in CP tissues or in Z310 cells. However, our findings revealed a significant decrease in the IDE activity following Pb exposure; this inhibition was similar to that seen in the cells treated with NEM alone. Interestingly, treatment with Pb or NEM alone significantly increased the levels of intracellular Aβ, and a greater accumulation of Aβ was seen when the cells were exposed to a combination of both. Conclusion These data suggest that Pb exposure inhibits IDE activity but does not affect its expression in the CP. This, in turn, leads to a disrupted metabolism of Aβ resulting in its accumulation at the blood-CSF barrier.
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Affiliation(s)
- Mamta Behl
- School of Health Sciences, Purdue University, West Lafayette, IN 47907, USA.
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