1
|
Peppriell AE, Gunderson JT, Krout IN, Vorojeikina D, Rand MD. Latent effects of early-life methylmercury exposure on motor function in Drosophila. Neurotoxicol Teratol 2021; 88:107037. [PMID: 34656729 DOI: 10.1016/j.ntt.2021.107037] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 09/25/2021] [Accepted: 10/10/2021] [Indexed: 12/27/2022]
Abstract
The developmental toxicant, methylmercury (MeHg), can elicit motor deficits that last well into adulthood. Recent studies using Drosophila showed that the developing musculature is sensitive to high doses of MeHg, where a larval feeding paradigm resulted in compromised myotendinous junction (MTJ) formation during development, by a mechanism involving the NG2 homologue, kon-tiki (kon). Low-dose exposures to MeHg that do not produce muscle pathology during development, nevertheless result in impaired flight behavior later in adult life. The present study evaluated the potential for relatively low-dose exposure to produce latent adult muscle pathology and motor impairments, as assayed by climbing and flight, as well as to evaluate molecular mechanisms that may contribute to motor deficits. Wildtype larvae were fed 0, 2, 2.5, or 5 μM MeHg laden food until eclosion. The effect of 5 μM MeHg on MTJ-related gene expression during pupal development was assessed via quantitative RT-qPCR analysis. Upon eclosion, adults were transferred to standard food bottles for 4, 11, or 30 days prior to motor testing. Survivorship (%) was determined from a subset of 200 flies per treatment. Average climbing speed (cm/s) was quantified 4-days post-eclosion (PE). Flight ability was assayed 11- or 30-days PE by measuring landing height (cm) of flies dropped into an adhesive-lined vertical column. In parallel, total body mercury was measured to estimate the influence of residual MeHg at the time of motor testing. Muscle morphology was assessed using immuno-fluorescence microscopy. Exposure to 5uM MeHg significantly reduced climbing speed, and flight ability 4 and 11 - days PE, respectively. While age-related flight deficits were seen in each sex, flight deficits due to MeHg persisted to 30-day PE timepoints exclusively in males. Expression of kon was upregulated across the window of pupal development essential to establishing adult MTJ. However, experimentally restricting the induction of comparable levels of kon to muscle during the same periods did not recapitulate the flight deficits, indicating that muscle-specific induction of kon alone is not sufficient to contribute to latent flight impairments. Adult flight muscle morphology of 11-day PE flies treated with 5 μM MeHg was indistinct from controls, implying muscle structure is not grossly perturbed to impair flight. Collectively, the current data suggest that developmental exposure to 5 μM MeHg reduces flight ability in each sex at 11 day-PE and that latent deficits at 30-day PE are male-specific. It remains to be determined whether the developing MTJ of Drosophila is a sensitive target of MeHg, and whether or not kon acts in conjunction with additional MTJ factors to constitute a MeHg target.
Collapse
Affiliation(s)
- Ashley E Peppriell
- Department of Environmental Medicine, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA; ICF International, Durham, NC, USA.
| | - Jakob T Gunderson
- Department of Environmental Medicine, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
| | - Ian N Krout
- Department of Environmental Medicine, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
| | - Daria Vorojeikina
- Department of Environmental Medicine, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
| | - Matthew D Rand
- Department of Environmental Medicine, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
| |
Collapse
|
2
|
Glazer L, Brennan CH. Developmental Exposure to Low Concentrations of Methylmercury Causes Increase in Anxiety-Related Behaviour and Locomotor Impairments in Zebrafish. Int J Mol Sci 2021; 22:10961. [PMID: 34681620 PMCID: PMC8535691 DOI: 10.3390/ijms222010961] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Revised: 09/22/2021] [Accepted: 09/29/2021] [Indexed: 11/17/2022] Open
Abstract
Methylmercury (MeHg) is a ubiquitous pollutant shown to cause developmental neurotoxicity, even at low levels. However, there is still a large gap in our understanding of the mechanisms linking early-life exposure to life-long behavioural impairments. Our aim was to characterise the short- and long-term effects of developmental exposure to low doses of MeHg on anxiety-related behaviours in zebrafish, and to test the involvement of neurological pathways related to stress-response. Zebrafish embryos were exposed to sub-acute doses of MeHg (0, 5, 10, 15, 30 nM) throughout embryo-development, and tested for anxiety-related behaviours and locomotor activity at larval (light/dark locomotor activity) and adult (novel tank and tap assays) life-stages. Exposure to all doses of MeHg caused increased anxiety-related responses; heightened response to the transition from light to dark in larvae, and a stronger dive response in adults. In addition, impairment in locomotor activity was observed in the higher doses in both larvae and adults. Finally, the expressions of several neural stress-response genes from the HPI-axis and dopaminergic system were found to be disrupted in both life-stages. Our results provide important insights into dose-dependent differences in exposure outcomes, the development of delayed effects over the life-time of exposed individuals and the potential mechanisms underlying these effects.
Collapse
Affiliation(s)
- Lilah Glazer
- Nanchang Joint Programme, School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, UK
| | - Caroline H. Brennan
- Department of Biological and Experimental Psychology, School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, UK;
| |
Collapse
|
3
|
Mechanisms of oxidative stress in methylmercury-induced neurodevelopmental toxicity. Neurotoxicology 2021; 85:33-46. [PMID: 33964343 DOI: 10.1016/j.neuro.2021.05.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 05/02/2021] [Accepted: 05/03/2021] [Indexed: 12/15/2022]
Abstract
Methylmercury (MeHg) is a long-lasting organic environmental pollutant that poses a great threat to human health. Ingestion of seafood containing MeHg is the most important way by which it comes into contact with human body, where the central nervous system (CNS) is the primary target of MeHg toxicity. During periods of pre-plus postnatal, in particular, the brain of offspring is vulnerable to specific developmental insults that result in abnormal neurobehavioral development, even without symptoms in mothers. While many studies on neurotoxic effects of MeHg on the developing brain have been conducted, the mechanisms of oxidative stress in MeHg-induced neurodevelopmental toxicity is less clear. Hitherto, no single process can explain the many effects observed in MeHg-induced neurodevelopmental toxicity. This review summarizes the possible mechanisms of oxidative stress in MeHg-induced neurodevelopmental toxicity, highlighting modulation of Nrf2/Keap1/Notch1, PI3K/AKT, and PKC/MAPK molecular pathways as well as some preventive drugs, and thus contributes to the discovery of endogenous and exogenous molecules that can counteract MeHg-induced neurodevelopmental toxicity.
Collapse
|
4
|
Ferrer B, Peres TV, Dos Santos AA, Bornhorst J, Morcillo P, Gonçalves CL, Aschner M. Methylmercury Affects the Expression of Hypothalamic Neuropeptides That Control Body Weight in C57BL/6J Mice. Toxicol Sci 2019; 163:557-568. [PMID: 29850906 DOI: 10.1093/toxsci/kfy052] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Methylmercury (MeHg) is an environmental pollutant that affects primarily the central nervous system (CNS), causing neurological alterations. An early symptom of MeHg poisoning is the loss of body weight and appetite. Moreover, the CNS has an important role in controlling energy homeostasis. It is known that in the hypothalamus nutrient and hormonal signals converge to orchestrate control of body weight and food intake. In this study, we investigated if MeHg is able to induce changes in the expression of key hypothalamic neuropeptides that regulate energy homeostasis. Thus, hypothalamic neuronal mouse cell line GT 1-7 was treated with MeHg at different concentrations (0, 0.5, 1, and 5 µM). MeHg induced the expression of the anorexigenic neuropeptide pro-omiomelanocortin (Pomc) and the orexigenic peptide Agouti-related peptide (Agrp) in a concentration-dependent manner, suggesting deregulation of mechanisms that control body weight. To confirm these in vitro observations, 8-week-old C57BL/6J mice (males and females) were exposed to MeHg in drinking water, modeling the most prevalent exposure route to this metal. After 30-day exposure, no changes in body weight were detected. However, MeHg treated males showed a significant decrease in fat depots. Moreover, MeHg affected the expression of hypothalamic neuropeptides that control food intake and body weight in a gender- and dose-dependent manner. Thus, MeHg increases Pomc mRNA only in males in a dose-dependent way, and it does not have effects on the expression of Agrp mRNA. The present study shows, for first time, that MeHg is able to induce changes in hypothalamic neuropeptides that regulate energy homeostasis, favoring an anorexigenic/catabolic profile.
Collapse
Affiliation(s)
- Beatriz Ferrer
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York 10461
| | - Tanara Vieira Peres
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York 10461
| | | | - Julia Bornhorst
- Department of Food Chemistry, Institute of Nutritional Science, University of Potsdam, 14558 Nuthetal, Germany
| | - Patricia Morcillo
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York 10461
| | - Cinara Ludvig Gonçalves
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York 10461
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York 10461
| |
Collapse
|
5
|
Antunes Dos Santos A, Ferrer B, Marques Gonçalves F, Tsatsakis AM, Renieri EA, Skalny AV, Farina M, Rocha JBT, Aschner M. Oxidative Stress in Methylmercury-Induced Cell Toxicity. TOXICS 2018; 6:toxics6030047. [PMID: 30096882 PMCID: PMC6161175 DOI: 10.3390/toxics6030047] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Revised: 08/03/2018] [Accepted: 08/07/2018] [Indexed: 02/06/2023]
Abstract
Methylmercury (MeHg) is a hazardous environmental pollutant, which elicits significant toxicity in humans. The accumulation of MeHg through the daily consumption of large predatory fish poses potential health risks, and the central nervous system (CNS) is the primary target of toxicity. Despite well-described neurobehavioral effects (i.e., motor impairment), the mechanisms of MeHg-induced toxicity are not completely understood. However, several lines of evidence point out the oxidative stress as an important molecular mechanism in MeHg-induced intoxication. Indeed, MeHg is a soft electrophile that preferentially interacts with nucleophilic groups (mainly thiols and selenols) from proteins and low-molecular-weight molecules. Such interaction contributes to the occurrence of oxidative stress, which can produce damage by several interacting mechanisms, impairing the function of various molecules (i.e., proteins, lipids, and nucleic acids), potentially resulting in modulation of different cellular signal transduction pathways. This review summarizes the general aspects regarding the interaction between MeHg with regulators of the antioxidant response system that are rich in thiol and selenol groups such as glutathione (GSH), and the selenoenzymes thioredoxin reductase (TrxR) and glutathione peroxidase (Gpx). A particular attention is directed towards the role of the PI3K/Akt signaling pathway and the nuclear transcription factor NF-E2-related factor 2 (Nrf2) in MeHg-induced redox imbalance.
Collapse
Affiliation(s)
| | - Beatriz Ferrer
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
| | - Filipe Marques Gonçalves
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
| | - Aristides M Tsatsakis
- Laboratory of Toxicology, Medical School, University of Crete, 71003 Heraklion, Greece.
| | - Elisavet A Renieri
- Laboratory of Toxicology, Medical School, University of Crete, 71003 Heraklion, Greece.
| | - Anatoly V Skalny
- Department of Medical Elementology, Peoples' Friendship University of Russia (RUDN University), Moscow 150000, Russia.
- Laboratory of Biotechnology and Applied Bioelementology, Yaroslavl State University, Yaroslavl 150014, Russia.
- All-Russian Research Institute of Medicinal and Aromatic Plants (VILAR), Moscow 150000, Russia.
| | - Marcelo Farina
- Department of Biochemistry, Federal University of Santa Catarina, Florianopolis 88040-900, Santa Catarina, Brazil.
| | - João B T Rocha
- Department of Biochemistry, Federal University of Santa Maria, Santa Maria 97105-900, Rio Grande do Sul, Brazil.
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
| |
Collapse
|
6
|
Developmental neurotoxicity of the hippocampus following in utero exposure to methylmercury: impairment in cell signaling. Arch Toxicol 2017; 92:513-527. [PMID: 28821999 DOI: 10.1007/s00204-017-2042-6] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Accepted: 08/10/2017] [Indexed: 01/01/2023]
Abstract
In this study, we assessed some hippocampal signaling cascades and behavioral impairments in 30-day-old rat pups prenatally exposed to methylmercury (MeHg). Pregnant rats were exposed to 1.0 or 2.0 mg/kg MeHg by gavage in alternated days from gestational day 5 until parturition. We found increased anxiety-like and decreased exploration behavior evaluated by open field test and deficit of both short- and long-term memories by novel object recognition task, respectively, in MeHg-treated pups. Downregulated PI3K/Akt/mTOR pathway and activated/hypophosphorylated (Ser9) GSK3β in MeHg-treated pups could be upstream of hyperphosphorylated Tau (Ser396) destabilizing microtubules and contributing to neural dysfunction in the hippocampus of these rats. Hyperphosphorylated/activated p38MAPK and downregulated phosphoErk1/2 support a role for mitogen-activated protein kinase (MAPK) cascade on MeHg neurotoxicity. Decreased receptor of advanced glycation end products (RAGE) immunocontent supports the assumption that downregulated RAGE/Erk1/2 pathway could be involved in hypophosphorylated lysine/serine/proline (KSP) repeats on neurofilament subunits and disturbed axonal transport. Downregulated myelin basic protein (MBP), the major myelin protein, is compatible with dysmyelination and neurofilament hypophosphorylation. Increased glial fibrillary acidic protein (GFAP) levels suggest reactive astrocytes, and active apoptotic pathways BAD/BCL-2, BAX/BCL-XL, and caspase 3 suggest cell death. Taken together, our findings get light on important signaling mechanisms that could underlie the behavioral deficits in 30-day-old pups prenatally exposed to MeHg.
Collapse
|
7
|
Kalia V, Perera F, Tang D. Environmental Pollutants and Neurodevelopment: Review of Benefits From Closure of a Coal-Burning Power Plant in Tongliang, China. Glob Pediatr Health 2017; 4:2333794X17721609. [PMID: 28812058 PMCID: PMC5542072 DOI: 10.1177/2333794x17721609] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Revised: 06/13/2017] [Accepted: 06/21/2017] [Indexed: 12/02/2022] Open
Abstract
Background. Understanding preventable causes of neurodevelopmental disorders is a public health priority. Polycyclic aromatic hydrocarbons (PAH) from combustion of fossil fuel, lead, and mercury are among known neurodevelopmental toxicants. Method. For the first time, we comprehensively review the findings from a study by the Columbia Center for Children's Environmental Health and Chinese partners that followed 2 groups of mother-child pairs, one from 2002 and another from 2005, in Tongliang County, China. Pregnant mothers in the 2 cohorts experienced different exposure to PAH because a local coal-burning power plant was shut down in 2004. Investigators assessed change in prenatal PAH exposure, measured using a biomarker (benzo[a]pyrene [BaP]-DNA adducts in cord blood). Developmental quotients were measured using the Gesell Developmental Scales at age 2 and IQ was assessed using the Wechsler Intelligence Scale for Children at age 5. Biologic markers of preclinical response were measured in cord blood: methylation status of long interspersed nuclear elements (LINE1), an indicator of genomic stability, and brain-derived neurotrophic factor (BDNF), a neuronal growth promoter. Analyses accounted for co-exposure to lead and mercury. Results. BaP-DNA adducts were significantly inversely associated with Gesell Developmental Scales scores in the first cohort but not in the second cohort; and levels of BDNF and LINE1 methylation were higher in the second cohort. Conclusion. In this study, reduced exposure to PAH was associated with beneficial effects on neurodevelopment as well as molecular changes related to improved brain development and health. These benefits should encourage further efforts to limit exposure to these toxic pollutants.
Collapse
Affiliation(s)
- Vrinda Kalia
- Department of Environmental Health Sciences, Columbia Center for Children’s Environemental Health, Mailman School of Public Health, Columbia University, New York, NY, USA
| | - Frederica Perera
- Department of Environmental Health Sciences, Columbia Center for Children’s Environemental Health, Mailman School of Public Health, Columbia University, New York, NY, USA
| | - Deliang Tang
- Department of Environmental Health Sciences, Columbia Center for Children’s Environemental Health, Mailman School of Public Health, Columbia University, New York, NY, USA
| |
Collapse
|
8
|
Edoff K, Raciti M, Moors M, Sundström E, Ceccatelli S. Gestational Age and Sex Influence the Susceptibility of Human Neural Progenitor Cells to Low Levels of MeHg. Neurotox Res 2017; 32:683-693. [PMID: 28756503 PMCID: PMC5602033 DOI: 10.1007/s12640-017-9786-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Revised: 07/09/2017] [Accepted: 07/12/2017] [Indexed: 01/13/2023]
Abstract
The developing nervous system is highly susceptible to methylmercury (MeHg), a widespread environmental neurotoxic contaminant. A wide range of morphological and functional outcomes have been described; however, there are still open questions regarding the mechanisms behind the developmental neurotoxic effects induced by low-level exposure. In the present study, we have examined the effects of nanomolar concentrations of MeHg on primary fetal human progenitor cells (hNPCs) with special focus on the role played by developmental stage and sex on the neurotoxic outcome. We found that neurospheres derived from earlier gestational time points exhibit higher susceptibility to MeHg, as they undergo apoptosis at a much lower dose (25 nM) as compared to neurospheres established from older fetuses (100 nM). At subapoptotic concentrations (10 nM), MeHg inhibited neuronal differentiation and maturation of hNPCs, as shown by a reduced number of Tuj1-positive cells and a visible reduction in neurite extension and cell migration, associated with a misregulation of Notch1 and BDNF signaling pathways. Interestingly, cells derived from male fetuses showed more severe alterations of neuronal morphology as compared to cells from females, indicating that the MeHg-induced impairment of neurite extension and cell migration is sex-dependent. Accordingly, the expression of the CDKL5 gene, a major factor regulating neurite outgrowth, was significantly more downregulated in male-derived cells. Altogether, gestational age and sex appear to be critical factors influencing in vitro hNPC sensitivity to low levels of MeHg.
Collapse
Affiliation(s)
- Karin Edoff
- Department of Neuroscience, Karolinska Institutet, Retzius väg 8, SE-171 77, Stockholm, Sweden
| | - Marilena Raciti
- Department of Neuroscience, Karolinska Institutet, Retzius väg 8, SE-171 77, Stockholm, Sweden.
| | - Michaela Moors
- Department of Neuroscience, Karolinska Institutet, Retzius väg 8, SE-171 77, Stockholm, Sweden
| | - Erik Sundström
- Department of Neurobiology, Care Sciences, and Society, Karolinska Institutet, Geriatrik-lab plan 5, SE-141 52, Huddinge, Sweden
| | - Sandra Ceccatelli
- Department of Neuroscience, Karolinska Institutet, Retzius väg 8, SE-171 77, Stockholm, Sweden
| |
Collapse
|
9
|
Engin AB, Engin ED, Golokhvast K, Spandidos DA, Tsatsakis AM. Glutamate‑mediated effects of caffeine and interferon‑γ on mercury-induced toxicity. Int J Mol Med 2017; 39:1215-1223. [PMID: 28350110 PMCID: PMC5403307 DOI: 10.3892/ijmm.2017.2937] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Accepted: 03/13/2017] [Indexed: 01/08/2023] Open
Abstract
The molecular mechanisms mediating mercury‑induced neurotoxicity are not yet completely understood. Thus, the aim of this study was to investigate whether the severity of MeHg‑ and HgCl2‑mediated cytotoxicity to SH‑SY5Y human dopaminergic neurons can be attenuated by regulating glutamate‑mediated signal‑transmission through caffeine and interferon‑γ (IFN‑γ). The SH‑SY5Y cells were exposed to 1, 2 and 5 µM of either MeHgCl2 or HgCl2 in the presence or absence of L‑glutamine. To examine the effect of adenosine receptor antagonist, the cells were treated with 10 and 20 µM caffeine. The total mitochondrial metabolic activity and oxidative stress intensity coefficient were determined in the 1 ng/ml IFN‑γ‑ and glutamate‑stimulated SH‑SY5Y cells. Following exposure to mercury, the concentration‑dependent decrease in mitochondrial metabolic activity inversely correlated with oxidative stress intensity. MeHg was more toxic than HgCl2. Mercury‑induced neuronal death was dependent on glutamate‑mediated excitotoxicity. Caffeine reduced the mercury‑induced oxidative stress in glutamine-containing medium. IFN‑γ treatment decreased cell viability and increased oxidative stress in glutamine‑free medium, despite caffeine supplementation. Although caffeine exerted a protective effect against MeHg-induced toxicity with glutamate transmission, under co‑stimulation with glutamine and IFN‑γ, caffeine decreased the MeHg‑induced average oxidative stress only by half. Thereby, our data indicate that the IFN‑γ stimulation of mercury‑exposed dopaminergic neurons in neuroinflammatory diseases may diminish the neuroprotective effects of caffeine.
Collapse
Affiliation(s)
- Ayse Basak Engin
- Department of Toxicology, Faculty of Pharmacy, Gazi University, Ankara 06330, Turkey
| | | | - Kirill Golokhvast
- Scientific Educational Center of Nanotechnology, Far Eastern Federal University, Engineering School, Vladivostok 690950, Russia
| | - Demetrios A Spandidos
- Laboratory of Clinical Virology, Medical School, University of Crete, Heraklion 71003, Greece
| | - Aristides M Tsatsakis
- Department of Forensic Sciences and Toxicology, Faculty of Medicine, University of Crete, Heraklion 71003, Greece
| |
Collapse
|
10
|
Antunes Dos Santos A, Appel Hort M, Culbreth M, López-Granero C, Farina M, Rocha JBT, Aschner M. Methylmercury and brain development: A review of recent literature. J Trace Elem Med Biol 2016; 38:99-107. [PMID: 26987277 PMCID: PMC5011031 DOI: 10.1016/j.jtemb.2016.03.001] [Citation(s) in RCA: 101] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2016] [Accepted: 03/02/2016] [Indexed: 02/02/2023]
Abstract
Methylmercury (MeHg) is a potent environmental pollutant, which elicits significant toxicity in humans. The central nervous system (CNS) is the primary target of toxicity, and is particularly vulnerable during development. Maternal exposure to MeHg via consumption of fish and seafood can have irreversible effects on the neurobehavioral development of children, even in the absence of symptoms in the mother. It is well documented that developmental MeHg exposure may lead to neurological alterations, including cognitive and motor dysfunction. The neurotoxic effects of MeHg on the developing brain have been extensively studied. The mechanism of toxicity, however, is not fully understood. No single process can explain the multitude of effects observed in MeHg-induced neurotoxicity. This review summarizes the most current knowledge on the effects of MeHg during nervous system development considering both, in vitro and in vivo experimental models. Considerable attention was directed towards the role of glutamate and calcium dyshomeostasis, mitochondrial dysfunction, as well as the effects of MeHg on cytoskeletal components/regulators.
Collapse
Affiliation(s)
| | - Mariana Appel Hort
- Institute of Biological Sciences, Federal University of Rio Grande, Campus Carreiros, Rio Grande do Sul, Brazil
| | - Megan Culbreth
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Caridad López-Granero
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Marcelo Farina
- Department of Biochemistry, Federal University of Santa Catarina, Florianopolis, Santa Catarina, Brazil
| | - Joao B T Rocha
- Department of Biochemistry, Federal University of Santa Maria, Santa Maria, Rio Grande do Sul, Brazil
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, USA.
| |
Collapse
|
11
|
Ruszkiewicz JA, Bowman AB, Farina M, Rocha JBT, Aschner M. Sex- and structure-specific differences in antioxidant responses to methylmercury during early development. Neurotoxicology 2016; 56:118-126. [PMID: 27456245 DOI: 10.1016/j.neuro.2016.07.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Revised: 07/21/2016] [Accepted: 07/21/2016] [Indexed: 01/02/2023]
Abstract
Methylmercury (MeHg) is a ubiquitous environmental contaminant and neurotoxin, particularly hazardous to developing and young individuals. MeHg neurotoxicity during early development has been shown to be sex-dependent via disturbances in redox homeostasis, a key event mediating MeHg neurotoxicity. Therefore, we investigated if MeHg-induced changes in key systems of antioxidant defense are sex-dependent. C57BL/6J mice were exposed to MeHg during the gestational and lactational periods, modeling human prenatal and neonatal exposure routes. Dams were exposed to 5ppm MeHg via drinking water from early gestational period until postnatal day 21 (PND21). On PND21 a pair of siblings (a female and a male) from multiple (5-6) litters were euthanized and tissue samples were taken for analysis. Cytoplasmic and nuclear extracts were isolated from fresh cerebrum and cerebellum and used to determine thioredoxin (Trx) and glutathione (GSH) levels, as well as thioredoxin reductase (TrxR) and glutathione peroxidase (GPx) activities. The remaining tissue was used for mRNA analysis. MeHg-induced antioxidant response was not uniform for all the analyzed antioxidant molecules, and sexual dimorphism in response to MeHg treatment was evident for TrxR, Trx and GPx. The pattern of response, namely a decrease in males and an increase in females, may impart differential and sex-specific susceptibility to MeHg. GSH levels were unchanged in MeHg treated animals and irrespective of sex. Trx was reduced only in nuclear extracts from male cerebella, exemplifying a structure-specific response. Results from the gene expression analysis suggest posttranscriptional mechanism of sex-specific regulation of the antioxidant response upon MeHg treatment. The study demonstrates for the first time sex-and structure-specific changes in the response of the thioredoxin system to MeHg neurotoxicity and suggests that these differences in antioxidant responses might impart differential susceptibility to developmental MeHg exposure.
Collapse
Affiliation(s)
- Joanna A Ruszkiewicz
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, USA.
| | - Aaron B Bowman
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Marcelo Farina
- Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, 88040900 Florianópolis, SC, Brazil
| | - João B T Rocha
- Departamento de Bioquímica e Biologia Molecular, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, 97105900 Santa Maria, RS, Brazil
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, USA.
| |
Collapse
|
12
|
Bragança M, Marinho M, Marques J, Moreira R, Palha A, Marques-Teixeira J, Esteves M. The influence of espresso coffee on neurocognitive function in HIV-infected patients. AIDS Care 2016; 28:1149-53. [PMID: 26932511 DOI: 10.1080/09540121.2016.1153589] [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] [Indexed: 10/22/2022]
Abstract
The aim of our study was to evaluate the impact of coffee intake on cognitive function in persons living with HIV (PLWH). 130 PLWH with CD4 > 200 cells/mm(3), undetectable viral load, treated with HAART were included. A structured interview was applied and relevant clinical and laboratory data were assessed, including coffee intake. For neuropsychological assessment, the HIV Neurobehavioral Research Center Battery was chosen. Univariate nonparametric statistics and multivariate regression model were used. A significant association between espresso coffee use and a better cognitive function was verified in five of the eight psychometric measurements. In the multivariate analysis, after variable adjustment, linear regression analysis showed that coffee intake was a positive predictor for attention/working memory, executive functions and Global Deficit Score. Although the mechanisms behind the influence of caffeine on cognitive functioning are controversial, regular espresso coffee intake may have favourable effects on cognitive deterioration caused by HIV.
Collapse
Affiliation(s)
- M Bragança
- a Department of Clinical Neurosciences and Mental Health, Faculty of Medicine , University of Porto , Porto , Portugal
| | - M Marinho
- a Department of Clinical Neurosciences and Mental Health, Faculty of Medicine , University of Porto , Porto , Portugal
| | - J Marques
- a Department of Clinical Neurosciences and Mental Health, Faculty of Medicine , University of Porto , Porto , Portugal
| | - R Moreira
- a Department of Clinical Neurosciences and Mental Health, Faculty of Medicine , University of Porto , Porto , Portugal
| | - A Palha
- a Department of Clinical Neurosciences and Mental Health, Faculty of Medicine , University of Porto , Porto , Portugal
| | - J Marques-Teixeira
- a Department of Clinical Neurosciences and Mental Health, Faculty of Medicine , University of Porto , Porto , Portugal
| | - M Esteves
- a Department of Clinical Neurosciences and Mental Health, Faculty of Medicine , University of Porto , Porto , Portugal
| |
Collapse
|
13
|
Rosi-Marshall EJ, Snow D, Bartelt-Hunt SL, Paspalof A, Tank JL. A review of ecological effects and environmental fate of illicit drugs in aquatic ecosystems. JOURNAL OF HAZARDOUS MATERIALS 2015; 282:18-25. [PMID: 25062553 DOI: 10.1016/j.jhazmat.2014.06.062] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Revised: 06/19/2014] [Accepted: 06/27/2014] [Indexed: 06/03/2023]
Abstract
Although illicit drugs are detected in surface waters throughout the world, their environmental fate and ecological effects are not well understood. Many illicit drugs and their breakdown products have been detected in surface waters and temporal and spatial variability in use translates into "hot spots and hot moments" of occurrence. Illicit drug occurrence in regions of production and use and areas with insufficient wastewater treatment are not well studied and should be targeted for further study. Evidence suggests that illicit drugs may not be persistent, as their half-lives are relatively short, but may exhibit "pseudo-persistence" wherein continual use results in persistent occurrence. We reviewed the literature on the ecological effects of these compounds on aquatic organisms and although research is limited, a wide array of aquatic organisms, including bacteria, algae, invertebrates, and fishes, have receptors that make them potentially sensitive to these compounds. In summary, illicit drugs occur in surface waters and aquatic organisms may be affected by these compounds; research is needed that focuses on concentrations of illicit drugs in areas of production and high use, environmental fate of these compounds, and effects of these compounds on aquatic ecosystems at the concentrations that typically occur in the environment.
Collapse
Affiliation(s)
- E J Rosi-Marshall
- Cary Institute of Ecosystem Studies, 2801 Sharon Turnpike, Millbrook, NY 12545, USA.
| | - D Snow
- University of Nebraska-Lincoln, Lincoln, NE 68583-0844, USA
| | | | - A Paspalof
- University of Nebraska-Lincoln, Lincoln, NE 68583-0844, USA
| | - J L Tank
- University of Notre Dame, Notre Dame, IN 46556, USA
| |
Collapse
|
14
|
Golding J, Emmett P, Iles-Caven Y, Steer C, Lingam R. A review of environmental contributions to childhood motor skills. J Child Neurol 2014; 29:1531-47. [PMID: 24170258 PMCID: PMC4004720 DOI: 10.1177/0883073813507483] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Although much of children's motor skills have a heredity component, at least half of the variance is likely to be influenced by the environment. It is important to ascertain features of the environment that are responsible so that toxins can be avoided, children at risk can be identified, and beneficial interventions initiated. This review outlines the results of published studies and recommends the areas where further research is required. We found much confusion with little comparability concerning the ages or measures used. Few studies had sufficient power and few allowed for confounders. We found that research to date implicates associations with prenatal drinking ≥4 drinks of alcohol per day; diabetes; taking antidepressant drugs; being deficient in iodine or iron; dietary fish; and postnatal depression. The child appearing to be most at risk was born of low birth weight (but not due to preterm delivery) or with neonatal problems.
Collapse
Affiliation(s)
- Jean Golding
- Centre for Child and Adolescent Health, School of Social and Community Medicine, University of Bristol, Bristol, United Kingdom
| | | | | | | | | |
Collapse
|
15
|
Zebrafish as a Model for Developmental Neurotoxicity Assessment: The Application of the Zebrafish in Defining the Effects of Arsenic, Methylmercury, or Lead on Early Neurodevelopment. TOXICS 2014. [DOI: 10.3390/toxics2030464] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
|
16
|
Giunta S, Andriolo V, Castorina A. Dual blockade of the A1 and A2A adenosine receptor prevents amyloid beta toxicity in neuroblastoma cells exposed to aluminum chloride. Int J Biochem Cell Biol 2014; 54:122-36. [PMID: 25058312 DOI: 10.1016/j.biocel.2014.07.009] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Revised: 06/25/2014] [Accepted: 07/11/2014] [Indexed: 02/06/2023]
Abstract
In a previous work we have shown that exposure to aluminum (Al) chloride (AlCl3) enhanced the neurotoxicity of the amyloid beta(25-35) fragment (Abeta(25-35)) in neuroblastoma cells and affected the expression of Alzheimer's disease (AD)-related genes. Caffein, a compound endowed with beneficial effects against AD, exerts neuroprotection primarily through its antagonist activity on A2A adenosine receptors (A2AR), although it also inhibits A1Rs with similar potency. Still, studies on the specific involvement of these receptors in neuroprotection in a model of combined neurotoxicity (Abeta(25-35)+AlCl3) are missing. To address this issue, cultured SH-SY5Y cells exposed to Abeta(25-35)+AlCl3 were assessed for cell viability, morphology, intracellular ROS activity and expression of apoptosis-, stress- and AD-related proteins. To define the role of A1R and A2ARs, pretreatment with caffein, specific receptor antagonists (DPCPX or SCH58261) or siRNA-mediated gene knockdown were delivered. Results indicate that AlCl3 treatment exacerbated Abeta(25-35) toxicity, increased ROS production, lipid peroxidation, β-secretase-1 (BACE1) and amyloid precursor protein (APP). Interestingly, SCH58261 successfully prevented toxicity associated to Abeta(25-35) only, whereas pretreatment with both DPCPX and SCH58261 was required to fully avert Abeta(25-35)+AlCl3-induced damage, suggesting that A1Rs might also be critically involved in protection during combined toxicity. The effects of caffein were mimicked by both N-acetyl cysteine, an antioxidant, and desferrioxamine, likely acting through distinct mechanisms. Altogether, our data establish a novel protective function associated with A1R inhibition in the setting of combined Abeta(25-35)+AlCl3 neurotoxicity, and expand our current knowledge on the potential beneficial role of caffein to prevent AD progression in subjects environmentally exposed to aluminum.
Collapse
Affiliation(s)
- Salvatore Giunta
- Department of Bio-Medical Sciences, Section of Anatomy and Histology, University of Catania, Italy
| | - Violetta Andriolo
- Department of Pediatrics and Public Health Sciences, University of Turin, Italy
| | - Alessandro Castorina
- Department of Bio-Medical Sciences, Section of Anatomy and Histology, University of Catania, Italy.
| |
Collapse
|
17
|
Radonjic M, Cappaert NLM, de Vries EFJ, de Esch CEF, Kuper FC, van Waarde A, Dierckx RAJO, Wadman WJ, Wolterbeek APM, Stierum RH, de Groot DMG. Delay and Impairment in Brain Development and Function in Rat Offspring After Maternal Exposure to Methylmercury. Toxicol Sci 2013; 133:112-24. [DOI: 10.1093/toxsci/kft024] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
|
18
|
Hassauer M, Kaiser E, Schneider K, Schuhmacher‐Wolz U. Collate the literature on toxicity data on mercury in experimental animals and humans (Part I – Data on organic mercury). ACTA ACUST UNITED AC 2012. [DOI: 10.2903/sp.efsa.2012.en-297] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Martin Hassauer
- Forschungs‐ und Beratungsinstitut Gefahrstoffe GmbH (FoBiG) Freiburg Germany
| | - Eva Kaiser
- Forschungs‐ und Beratungsinstitut Gefahrstoffe GmbH (FoBiG) Freiburg Germany
| | - Klaus Schneider
- Forschungs‐ und Beratungsinstitut Gefahrstoffe GmbH (FoBiG) Freiburg Germany
| | | |
Collapse
|
19
|
Woods JS, Heyer NJ, Echeverria D, Russo JE, Martin MD, Bernardo MF, Luis HS, Vaz L, Farin FM. Modification of neurobehavioral effects of mercury by a genetic polymorphism of coproporphyrinogen oxidase in children. Neurotoxicol Teratol 2012; 34:513-21. [PMID: 22765978 DOI: 10.1016/j.ntt.2012.06.004] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2012] [Revised: 06/22/2012] [Accepted: 06/23/2012] [Indexed: 12/15/2022]
Abstract
Mercury (Hg) is neurotoxic, and children may be particularly susceptible to this effect. A current major challenge is the identification of children who may be uniquely susceptible to Hg toxicity because of genetic disposition. We examined the hypothesis that CPOX4, a genetic variant of the heme pathway enzyme coproporphyrinogen oxidase (CPOX) that affects susceptibility to mercury toxicity in adults, also modifies the neurotoxic effects of Hg in children. Five hundred seven children, 8-12 years of age at baseline, participated in a clinical trial to evaluate the neurobehavioral effects of Hg from dental amalgam tooth fillings in children. Subjects were evaluated at baseline and at 7 subsequent annual intervals for neurobehavioral performance and urinary mercury levels. Following the completion of the clinical trial, genotyping assays for CPOX4 allelic status were performed on biological samples provided by 330 of the trial participants. Regression modeling strategies were employed to evaluate associations between CPOX4 status, Hg exposure, and neurobehavioral test outcomes. Among girls, few significant CPOX4-Hg interactions or independent main effects for Hg or CPOX4 were observed. In contrast, among boys, numerous significant interaction effects between CPOX4 and Hg were observed spanning all 5 domains of neurobehavioral performance. All underlying dose-response associations between Hg exposure and test performance were restricted to boys with the CPOX4 variant, and all of these associations were in the expected direction where increased exposure to Hg decreased performance. These findings are the first to demonstrate genetic susceptibility to the adverse neurobehavioral effects of Hg exposure in children. The paucity of responses among same-age girls with comparable Hg exposure provides evidence of sexual dimorphism in genetic susceptibility to the adverse neurobehavioral effects of Hg in children and adolescents.
Collapse
Affiliation(s)
- James S Woods
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA 98105, USA.
| | | | | | | | | | | | | | | | | |
Collapse
|
20
|
Brent RL, Christian MS, Diener RM. Evaluation of the reproductive and developmental risks of caffeine. BIRTH DEFECTS RESEARCH. PART B, DEVELOPMENTAL AND REPRODUCTIVE TOXICOLOGY 2011; 92:152-87. [PMID: 21370398 PMCID: PMC3121964 DOI: 10.1002/bdrb.20288] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 09/29/2010] [Revised: 01/18/2011] [Accepted: 01/23/2011] [Indexed: 11/12/2022]
Abstract
A risk analysis of in utero caffeine exposure is presented utilizing epidemiological studies and animal studies dealing with congenital malformation, pregnancy loss, and weight reduction. These effects are of interest to teratologists, because animal studies are useful in their evaluation. Many of the epidemiology studies did not evaluate the impact of the "pregnancy signal," which identifies healthy pregnancies and permits investigators to identify subjects with low pregnancy risks. The spontaneous abortion epidemiology studies were inconsistent and the majority did not consider the confounding introduced by not considering the pregnancy signal. The animal studies do not support the concept that caffeine is an abortafacient for the wide range of human caffeine exposures. Almost all the congenital malformation epidemiology studies were negative. Animal pharmacokinetic studies indicate that the teratogenic plasma level of caffeine has to reach or exceed 60 µg/ml, which is not attainable from ingesting large amounts of caffeine in foods and beverages. No epidemiological study described the "caffeine teratogenic syndrome." Six of the 17 recent epidemiology studies dealing with the risk of caffeine and fetal weight reduction were negative. Seven of the positive studies had growth reductions that were clinically insignificant and none of the studies cited the animal literature. Analysis of caffeine's reproductive toxicity considers reproducibility and plausibility of clinical, epidemiological, and animal data. Moderate or even high amounts of beverages and foods containing caffeine do not increase the risks of congenital malformations, miscarriage or growth retardation. Pharmacokinetic studies markedly improve the ability to perform the risk analyses.
Collapse
Affiliation(s)
- Robert L Brent
- Thomas Jefferson University, Alfred I. duPont Hospital for Children, Wilmington, Delaware 19899, USA.
| | | | | |
Collapse
|
21
|
Gundacker C, Gencik M, Hengstschläger M. The relevance of the individual genetic background for the toxicokinetics of two significant neurodevelopmental toxicants: mercury and lead. Mutat Res 2010; 705:130-140. [PMID: 20601101 DOI: 10.1016/j.mrrev.2010.06.003] [Citation(s) in RCA: 98] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2010] [Revised: 06/07/2010] [Accepted: 06/10/2010] [Indexed: 11/25/2022]
Abstract
The heavy metals mercury and lead are well-known and significant developmental neurotoxicants. This review summarizes the genetic factors that modify their toxicokinetics. Understanding toxicokinetics (uptake, biotransformation, distribution, and elimination processes) is a key precondition to understanding the individual health risks associated with exposure. We selected candidate susceptibility genes when evidence was available for (1) genes/proteins playing a significant role in mercury and lead toxicokinetics, (2) gene expression/protein activity being induced by these metals, and (3) mercury and lead toxicokinetics being affected by gene knockout/knockdown or (4) by functional gene polymorphisms. The genetic background is far better known for mercury than for lead toxicokinetics. Involved are genes encoding L-type amino acid transporters, organic anion transporters, glutathione (GSH)-related enzymes, metallothioneins, and transporters of the ABC family. Certain gene variants can influence mercury toxicokinetics, potentially explaining part of the variable susceptibility to mercury toxicity. Delta-aminolevulinic acid dehydratase (ALAD), vitamin D receptor (VDR) and hemochromatosis (HFE) gene variants are the only well-established susceptibility markers of lead toxicity in humans. Many gaps remain in our knowledge about the functional genomics of this issue. This calls for studies to detect functional gene polymorphisms related to mercury- and lead-associated disease phenotypes, to demonstrate the impact of functional polymorphisms and gene knockout/knockdown in relation to toxicity, to confirm the in vivo relevance of genetic variation, and to examine gene-gene interactions on the respective toxicokinetics. Another crucial aspect is knowledge on the maternal-fetal genetic background, which modulates fetal exposure to these neurotoxicants. To completely define the genetically susceptible risk groups, research is also needed on the genes/proteins involved in the toxicodynamics, i.e., in the mechanisms causing adverse effects in the brain. Studies relating the toxicogenetics to neurodevelopmental disorders are lacking (mercury) or very scarce (lead). Thus, the extent of variability in susceptibility to heavy metal-associated neurological outcomes is poorly characterized.
Collapse
Affiliation(s)
- Claudia Gundacker
- Institute of Medical Genetics, Medical University of Vienna, Währinger Strasse 10, A-1090 Vienna, Austria.
| | - Martin Gencik
- Praxis fur Humangenetik, Brünnlbadgasse 15, A-1090 Vienna, Austria
| | - Markus Hengstschläger
- Institute of Medical Genetics, Medical University of Vienna, Währinger Strasse 10, A-1090 Vienna, Austria
| |
Collapse
|
22
|
Rahman A. The role of adenosine in Alzheimer's disease. Curr Neuropharmacol 2009; 7:207-16. [PMID: 20190962 PMCID: PMC2769004 DOI: 10.2174/157015909789152119] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2009] [Revised: 05/15/2009] [Accepted: 05/27/2009] [Indexed: 12/20/2022] Open
Abstract
Alzheimer's disease (AD) is a neurodegenerative disorder of the central nervous system manifested by cognitive and memory deterioration, a variety of neuropsychiatric symptoms, behavioral disturbances, and progressive impairment of daily life activities. Current pharmacotherapies are restricted to symptomatic interventions but do not prevent progressive neuronal degeneration. Therefore, new therapeutic strategies are needed to intervene with these progressive pathological processes. In the past several years adenosine, a ubiquitously released purine ribonucleoside, has become important for its neuromodulating capability and its emerging positive experimental effects in neurodegenerative diseases. Recent research suggests that adenosine receptors play important roles in the modulation of cognitive function. The present paper attempts to review published reports and data from different studies showing the evidence of a relationship between adenosinergic function and AD-related cognitive deficits. Epidemiological studies have found an association between coffee (a nonselective adenosine receptor antagonist) consumption and improved cognitive function in AD patients and in the elderly. Long-term administration of caffeine in transgenic animal models showed a reduced amyloid burden in brain with better cognitive performance. Antagonists of adenosine A2A receptors mimic these beneficial effects of caffeine on cognitive function. Neuronal cell cultures with amyloid beta in the presence of an A2A receptor antagonist completely prevented amyloid beta-induced neurotoxicity. These findings suggest that the adenosinergic system constitutes a new therapeutic target for AD, and caffeine and A2A receptor antagonists may have promise to manage cognitive dysfunction in AD.
Collapse
Affiliation(s)
- Anisur Rahman
- Legacy Research, R.S Dow Neurobiology Laboratories, 1225 NE 2nd Avenue, Portland OR 97232, USA.
| |
Collapse
|
23
|
Malagutti KS, da Silva AP, Braga HC, Mitozo PA, Soares Dos Santos AR, Dafre AL, de Bem AF, Farina M. 17β-estradiol decreases methylmercury-induced neurotoxicity in male mice. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2009; 27:293-297. [PMID: 21783955 DOI: 10.1016/j.etap.2008.11.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2008] [Revised: 11/09/2008] [Accepted: 11/12/2008] [Indexed: 05/31/2023]
Abstract
There is increasing evidence that health effects of toxic metals, including methylmercury (MeHg), differ in prevalence or are manifested differently in men and women. The present study was aimed at investigating the potential differential susceptibility of male and female Swiss mice against MeHg-induced neurotoxicity, which was evaluated by biochemical (cerebellar oxidative stress-related parameters) and behavioral (locomotor activity and motor performance) variables. We also aimed to evaluate the potential protective effects of 17β-estradiol against such toxicity in MeHg-exposed male animals. MeHg exposure (40mg/L, diluted in tap water, during 2 weeks) decreased locomotor activity and motor performance in both male and female animals, but such phenomena were higher in males. 17β-estradiol co-treatment (10μg/animal, in alternate days) prevented MeHg-induced locomotor deficits in males. MeHg exposure caused a significant increase (60%) in cerebellar lipid peroxidation in male mice, but did not in females. In close agreement, MeHg exposure decreased (43%) cerebellar glutathione peroxidase activity in males, but did not in females. These events were prevented by 17β-estradiol administration. Cerebellar GR activity was increased (25%) in MeHg-exposed males and such event was partially prevented by 17β-estradiol administration. These results indicate that the low susceptibility of female mice to the neurotoxicity elicited by MeHg is linked to neuroprotective effects of sex steroids, which appear to modulate the activities of glutathione-related enzymes. Our experimental observation corroborates previous epidemiological studies showing the greater developmental effects in male than in female humans exposed to MeHg.
Collapse
Affiliation(s)
- Keller Samara Malagutti
- Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianópolis, SC, Brazil
| | | | | | | | | | | | | | | |
Collapse
|
24
|
Björklund O, Kahlström J, Salmi P, Fredholm BB. Perinatal caffeine, acting on maternal adenosine A(1) receptors, causes long-lasting behavioral changes in mouse offspring. PLoS One 2008; 3:e3977. [PMID: 19092996 PMCID: PMC2597749 DOI: 10.1371/journal.pone.0003977] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2008] [Accepted: 11/14/2008] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND There are lingering concerns about caffeine consumption during pregnancy or the early postnatal period, partly because there may be long-lasting behavioral changes after caffeine exposure early in life. METHODOLOGY/PRINCIPAL FINDINGS We show that pregnant wild type (WT) mice given modest doses of caffeine (0.3 g/l in drinking water) gave birth to offspring that as adults exhibited increased locomotor activity in an open field. The offspring also responded to cocaine challenge with greater locomotor activity than mice not perinatally exposed to caffeine. We performed the same behavioral experiments on mice heterozygous for adenosine A(1) receptor gene (A(1)RHz). In these mice signaling via adenosine A(1) receptors is reduced to about the same degree as after modest consumption of caffeine. A(1)RHz mice had a behavioral profile similar to WT mice perinatally exposed to caffeine. Furthermore, it appeared that the mother's genotype, not offspring's, was critical for behavioral changes in adult offspring. Thus, if the mother partially lacked A(1) receptors the offspring displayed more hyperactivity and responded more strongly to cocaine stimulation as adults than did mice of a WT mother, regardless of their genotype. This indicates that long-term behavioral alterations in the offspring result from the maternal effect of caffeine, and not a direct effect on fetus. WT offspring from WT mother but having a A(1)R Hz grandmother preserved higher locomotor response to cocaine. CONCLUSIONS/SIGNIFICANCE We suggest that perinatal caffeine, by acting on adenosine A(1) receptors in the mother, causes long-lasting behavioral changes in the offspring that even manifest themselves in the second generation.
Collapse
Affiliation(s)
- Olga Björklund
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden.
| | | | | | | |
Collapse
|
25
|
Decreased behavioral activation following caffeine, amphetamine and darkness in A3 adenosine receptor knock-out mice. Physiol Behav 2008; 95:668-76. [DOI: 10.1016/j.physbeh.2008.09.018] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2007] [Revised: 09/17/2008] [Accepted: 09/19/2008] [Indexed: 11/22/2022]
|
26
|
Yang JN, Björklund O, Lindström-Törnqvist K, Lindgren E, Eriksson TM, Kahlström J, Chen JF, Schwarzschild MA, Tobler I, Fredholm BB. Mice heterozygous for both A1 and A(2A) adenosine receptor genes show similarities to mice given long-term caffeine. J Appl Physiol (1985) 2008; 106:631-9. [PMID: 19036889 DOI: 10.1152/japplphysiol.90971.2008] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Caffeine is believed to exert its stimulant effects by blocking A(2A) and A(1) adenosine receptors (A(2A)R and A(1)R). Although a genetic knockout of A(2A)R eliminates effects of caffeine, the phenotype of the knockout animal does not resemble that of caffeine treatment. In this study we explored the possibility that a mere reduction of the number of A(1)Rs and A(2A)Rs, achieved by deleting one of the two copies of the A(1)R and A(2A)R genes, would mimic some aspects of long-term caffeine ingestion. The A(1)R and A(2A)R double heterozygous (A(1)R-A(2A)R dHz) mice indeed had approximately one-half the number of A(1)R and A(2A)R, and there were little compensatory changes in A(2B) or A(3) adenosine receptor (A(2B)R or A(3)R) expression. The ability of a stable adenosine analog to activate receptors was shifted to the right by caffeine and in A(1)R-A(2A)R dHz tissue. Caffeine (0.3 g/l in drinking water for 7-10 days) and A(1)R-A(2A)R dHz genotype increased locomotor activity (LA) and decreased heart rate without significantly influencing body temperature. The acute stimulatory effect of a single injection of caffeine was reduced in A(1)R-A(2A)R dHz mice and in mice treated long term with oral caffeine. Thus at least some aspects of long-term caffeine use can be mimicked by genetic manipulation of the A(1)R and A(2A)R.
Collapse
Affiliation(s)
- Jiang-Ning Yang
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
27
|
Rosso A, Mossey J, Lippa CF. Caffeine: neuroprotective functions in cognition and Alzheimer's disease. Am J Alzheimers Dis Other Demen 2008; 23:417-22. [PMID: 19230121 PMCID: PMC10846190 DOI: 10.1177/1533317508320083] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/03/2024]
Abstract
Alzheimer's disease is a common problem in our elderly population. Although research is leading to improvements in our understanding of the underlying biology, we still have little understanding of the environmental risk factors associated with this disorder. Caffeine, an easily modifiable environmental factor, may have a protective effect on the likelihood of developing Alzheimer's disease. This article reviews the association between caffeine from both a biologic and epidemiologic perspective. Further studies are needed to determine whether caffeine consumption could have a major affect on the development of Alzheimer's disease or age-related cognitive decline.
Collapse
Affiliation(s)
- Andi Rosso
- Department of Neurology, Drexel University College of Medicine, Philadelphia, PA 19102, USA.
| | | | | |
Collapse
|