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Meerman JJ, Legler J, Piersma AH, Westerink RHS, Heusinkveld HJ. An adverse outcome pathway for chemical-induced Parkinson's disease: Calcium is key. Neurotoxicology 2023; 99:226-243. [PMID: 37926220 DOI: 10.1016/j.neuro.2023.11.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Revised: 10/25/2023] [Accepted: 11/01/2023] [Indexed: 11/07/2023]
Abstract
Exposure to pesticides is associated with an increased risk of developing Parkinson's disease (PD). Currently, rodent-based risk assessment studies cannot adequately capture neurodegenerative effects of pesticides due to a lack of human-relevant endpoints targeted at neurodegeneration. Thus, there is a need for improvement of the risk assessment guidelines. Specifically, a mechanistic assessment strategy, based on human physiology and (patho)biology is needed, which can be applied in next generation risk assessment. The Adverse Outcome Pathway (AOP) framework is particularly well-suited to provide the mechanistic basis for such a strategy. Here, we conducted a semi-systematic review in Embase and MEDLINE, focused on neurodegeneration and pesticides, to develop an AOP network for parkinsonian motor symptoms. Articles were labelled and included/excluded using the online platform Sysrev. Only primary articles, written in English, focused on effects of pesticides or PD model compounds in models for the brain were included. A total of 66 articles, out of the 1700 screened, was included. PD symptoms are caused by loss of function and ultimately death of dopaminergic neurons in the substantia nigra (SN). Our literature review highlights that a unique feature of these cells that increases their vulnerability is their reliance on continuous low-level influx of calcium. As such, excess intracellular calcium was identified as a central early Key Event (KE). This KE can lead to death of dopaminergic neurons of the SN, and eventually parkinsonian motor symptoms, via four distinct pathways: 1) activation of calpains, 2) endoplasmic reticulum stress, 3) impairment of protein degradation, and 4) oxidative damage. Several receptors have been identified that may serve as molecular initiating events (MIEs) to trigger one or more of these pathways. The proposed AOP network provides the biological basis that can be used to develop a mechanistic testing strategy that captures neurodegenerative effects of pesticides.
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Affiliation(s)
- Julia J Meerman
- Centre for Health Protection, Dutch National Institute for Public Health and the Environment (RIVM), Antonie van Leeuwenhoeklaan 9, 3721 MA Bilthoven, the Netherlands; Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands
| | - Juliette Legler
- Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands
| | - Aldert H Piersma
- Centre for Health Protection, Dutch National Institute for Public Health and the Environment (RIVM), Antonie van Leeuwenhoeklaan 9, 3721 MA Bilthoven, the Netherlands; Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands
| | - Remco H S Westerink
- Institute for Risk Assessment Sciences (IRAS), Faculty of Veterinary Medicine, Utrecht University, Utrecht, the Netherlands
| | - Harm J Heusinkveld
- Centre for Health Protection, Dutch National Institute for Public Health and the Environment (RIVM), Antonie van Leeuwenhoeklaan 9, 3721 MA Bilthoven, the Netherlands.
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Costas-Ferreira C, Faro LRF. Systematic Review of Calcium Channels and Intracellular Calcium Signaling: Relevance to Pesticide Neurotoxicity. Int J Mol Sci 2021; 22:ijms222413376. [PMID: 34948173 PMCID: PMC8704302 DOI: 10.3390/ijms222413376] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 12/06/2021] [Accepted: 12/08/2021] [Indexed: 12/25/2022] Open
Abstract
Pesticides of different chemical classes exert their toxic effects on the nervous system by acting on the different regulatory mechanisms of calcium (Ca2+) homeostasis. Pesticides have been shown to alter Ca2+ homeostasis, mainly by increasing its intracellular concentration above physiological levels. The pesticide-induced Ca2+ overload occurs through two main mechanisms: the entry of Ca2+ from the extracellular medium through the different types of Ca2+ channels present in the plasma membrane or its release into the cytoplasm from intracellular stocks, mainly from the endoplasmic reticulum. It has also been observed that intracellular increases in the Ca2+ concentrations are maintained over time, because pesticides inhibit the enzymes involved in reducing its levels. Thus, the alteration of Ca2+ levels can lead to the activation of various signaling pathways that generate oxidative stress, neuroinflammation and, finally, neuronal death. In this review, we also discuss some proposed strategies to counteract the detrimental effects of pesticides on Ca2+ homeostasis.
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Azevedo RDS, Falcão KVG, Assis CRD, Martins RMG, Araújo MC, Yogui GT, Neves JL, Seabra GM, Maia MBS, Amaral IPG, Leite ACR, Bezerra RS. Effects of pyriproxyfen on zebrafish brain mitochondria and acetylcholinesterase. CHEMOSPHERE 2021; 263:128029. [PMID: 33297050 DOI: 10.1016/j.chemosphere.2020.128029] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 08/12/2020] [Accepted: 08/13/2020] [Indexed: 06/12/2023]
Abstract
Pyriproxyfen is an insecticide used worldwide that acts as a biomimetic of juvenile hormone. This study investigated metabolic and synaptic impairments triggered by pyriproxyfen using zebrafish acetylcholinesterase (zbAChE) and mitochondria as markers. A brain zbAChE assay was performed in vitro and in vivo covering a range of pyriproxyfen concentrations (0.001-10 μmol/L) to assess inhibition kinetics. Docking simulations were performed to characterize inhibitory interactions. Zebrafish male adults were acutely exposed to 0.001, 0.01 and 0.1 μg/mL pyriproxyfen for 16 h. Mitochondrial respiration of brain tissues was assessed. ROS generation was estimated using H2DCF-DA and MitoSOX. Calcium transport was monitored by Calcium Green™ 5 N. NO synthesis activity was estimated using DAF-FM-DA. Brain acetylcholinesterase showed an in vivo IC20 of 0.30 μmol/L pyriproxyfen, and an IC50 of 92.5 μmol/L. The inhibitory effect on zbAChE activity was competitive-like. Respiratory control of Complex I/II decreased significantly after insecticide exposure. The MitoSOX test showed that O2- generation had a pyriproxyfen dose-dependent effect. Brain tissue lost 50% of Ca2+ uptake capacity at 0.1 μg/mL pyriproxyfen. Ca2+ release showed a clear mitochondrial impairment at lower pyriproxyfen exposures. Thus, Ca2+ transport imbalance caused by pyriproxyfen may be a novel deleterious mechanism of action. Overall, the results showed that pyriproxyfen can compromise multiple and interconnected pathways: (1) zbAChE impairment and (2) the functioning of the electron transport chain, ROS generation and calcium homeostasis in zebrafish brain mitochondria. Considering the many similarities between zebrafish and human, more caution is needed when pyriproxyfen is used in both urban and agricultural pest control.
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Affiliation(s)
- Rafael D S Azevedo
- Laboratório de Enzimologia - LABENZ, Departamento de Bioquímica, Universidade Federal de Pernambuco, Recife, PE, Brazil.
| | - Kivia V G Falcão
- Laboratório de Enzimologia - LABENZ, Departamento de Bioquímica, Universidade Federal de Pernambuco, Recife, PE, Brazil.
| | - Caio R D Assis
- Laboratório de Enzimologia - LABENZ, Departamento de Bioquímica, Universidade Federal de Pernambuco, Recife, PE, Brazil; Laboratório de Compostos Orgânicos em Ecossistemas Costeiros e Marinhos - OrganoMAR, Departamento de Oceanografia, Universidade Federal de Pernambuco, Recife, PE, Brazil.
| | | | - Marlyete C Araújo
- Laboratório de Enzimologia - LABENZ, Departamento de Bioquímica, Universidade Federal de Pernambuco, Recife, PE, Brazil.
| | - Gilvan T Yogui
- Laboratório de Compostos Orgânicos em Ecossistemas Costeiros e Marinhos - OrganoMAR, Departamento de Oceanografia, Universidade Federal de Pernambuco, Recife, PE, Brazil.
| | - Jorge L Neves
- Laboratório de Química Biológica - LQB, Departamento de Química Fundamental, Universidade Federal de Pernambuco, Recife, PE, Brazil.
| | - Gustavo M Seabra
- Department of Medicinal Chemistry and Center for Natural Products, Drug Discovery and Development (CNPD3), School of Pharmacy, University of Florida, Gainesville, FL, USA.
| | - Maria B S Maia
- Laboratório de Farmacologia de Produtos Bioativos, Departamento de Fisiologia e Farmacologia, Universidade Federal de Pernambuco, Recife, PE, Brazil.
| | - Ian P G Amaral
- Centro de Biotecnologia, Universidade Federal da Paraiba (UFPB), Campus I, Cidade Universitária, João Pessoa, PB, Brazil.
| | - Ana C R Leite
- Laboratório de Bioenergética Prof. Aníbal Vercesi, Departamento de Química e Biotecnologia, Universidade Federal de Alagoas (UFAL), Maceió, AL, Brazil.
| | - Ranilson S Bezerra
- Laboratório de Enzimologia - LABENZ, Departamento de Bioquímica, Universidade Federal de Pernambuco, Recife, PE, Brazil.
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Liu S, Yu M, Xie X, Ru Y, Ru S. Carbofuran induces increased anxiety-like behaviors in female zebrafish (Danio rerio) through disturbing dopaminergic/norepinephrinergic system. CHEMOSPHERE 2020; 253:126635. [PMID: 32278909 DOI: 10.1016/j.chemosphere.2020.126635] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 03/23/2020] [Accepted: 03/25/2020] [Indexed: 06/11/2023]
Abstract
Carbofuran, a carbamate pesticide, is widely used in developing countries to manage insect pests. Studies have found that carbofuran posed potential risks for the neurotransmitter systems of non-target species, we speculated that these disruptive effects on the neurotransmitter systems could trigger anxiety-like behaviors. In this study, female zebrafish were exposed to environmental levels (5, 50, and 500 μg/L) of carbofuran for 48 h to evaluate the effects of carbofuran on anxiety-like behaviors. Results showed that zebrafish exhibited more anxiety-like behaviors which proved by the observed higher bottom trend and more erratic movements in the novel tank after carbofuran treatment. In order to elucidate the underlying molecular mechanisms of carbofuran-induced anxiety-promoting effects, we measured the levels of neurotransmitters, precursors, and major metabolites, along with the level of gene expression and the enzyme activities involved in neurotransmitter synthesis and metabolism. The results demonstrated that acute carbofuran exposure stimulated the mRNA expression and enzyme activity of tyrosine hydroxylase, which sequentially induced the increased levels of dopamine and norepinephrine. Tyrosine hydroxylase inhibitor relieved the anxiety-related changes induced by carbofuran, confirming the overactive tyrosine hydroxylase-mediated accumulation of dopamine and norepinephrine in the brain was one of the main reasons for carbofuran-induced anxiety-like behaviors in the female zebrafish. Overall, our study indicated the environmental health risks of carbamate pesticide in inducing neurobehavioral disorders and provided novel insights into the investigation of the relevant underlying mechanisms.
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Affiliation(s)
- Shuang Liu
- College of Marine Life Sciences, Ocean University of China, Qingdao, 266003, China
| | - Miao Yu
- College of Life Science, Langfang Normal University, Langfang, 065000, China.
| | - Xincen Xie
- College of Marine Life Sciences, Ocean University of China, Qingdao, 266003, China
| | - Yiran Ru
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, 92093, USA
| | - Shaoguo Ru
- College of Marine Life Sciences, Ocean University of China, Qingdao, 266003, China.
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Carbofuran hampers oligodendrocytes development leading to impaired myelination in the hippocampus of rat brain. Neurotoxicology 2019; 70:161-179. [DOI: 10.1016/j.neuro.2018.11.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Revised: 11/14/2018] [Accepted: 11/20/2018] [Indexed: 11/21/2022]
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Seth B, Yadav A, Agarwal S, Tiwari SK, Chaturvedi RK. Inhibition of the transforming growth factor-β/SMAD cascade mitigates the anti-neurogenic effects of the carbamate pesticide carbofuran. J Biol Chem 2017; 292:19423-19440. [PMID: 28982980 DOI: 10.1074/jbc.m117.798074] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2017] [Revised: 09/29/2017] [Indexed: 12/22/2022] Open
Abstract
The widely used carbamate pesticide carbofuran causes neurophysiological and neurobehavioral deficits in rodents and humans and therefore poses serious health hazards around the world. Previously, we reported that gestational carbofuran exposure has detrimental effects on hippocampal neurogenesis, the generation of new neurons from neural stem cells (NSC), in offspring. However, the underlying cellular and molecular mechanisms for carbofuran-impaired neurogenesis remain unknown. Herein, we observed that chronic carbofuran exposure from gestational day 7 to postnatal day 21 altered expression of genes and transcription factors and levels of proteins involved in neurogenesis and the TGF-β pathway (i.e. TGF-β; SMAD-2, -3, and -7; and SMURF-2) in the rat hippocampus. We found that carbofuran increases TGF-β signaling (i.e. increased phosphorylated SMAD-2/3 and reduced SMAD-7 expression) in the hippocampus, which reduced NSC proliferation because of increased p21 levels and reduced cyclin D1 levels. Moreover, the carbofuran-altered TGF-β signaling impaired neuronal differentiation (BrdU/DCX+ and BrdU/NeuN+ cells) and increased apoptosis and neurodegeneration in the hippocampus. Blockade of the TGF-β pathway with the specific inhibitor SB431542 and via SMAD-3 siRNA prevented carbofuran-mediated inhibition of neurogenesis in both hippocampal NSC cultures and the hippocampus, suggesting the specific involvement of this pathway. Of note, both in vitro and in vivo studies indicated that TGF-β pathway attenuation reverses carbofuran's inhibitory effects on neurogenesis and associated learning and memory deficits. These results suggest that carbofuran inhibits NSC proliferation and neuronal differentiation by altering TGF-β signaling. Therefore, we conclude that TGF-β may represent a potential therapeutic target against carbofuran-mediated neurotoxicity and neurogenesis disruption.
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Affiliation(s)
- Brashket Seth
- From the Developmental Toxicology Laboratory, Systems Toxicology and Health Risk Assessment Group, CSIR-Indian Institute of Toxicology Research (CSIR-IITR), Vishvigyan Bhavan, 31, Mahatma Gandhi Marg, Lucknow 226001, Uttar Pradesh, India.,the Academy of Scientific and Innovative Research (AcSIR), CSIR-IITR Lucknow Campus, Lucknow 226001, Uttar Pradesh, India
| | - Anuradha Yadav
- From the Developmental Toxicology Laboratory, Systems Toxicology and Health Risk Assessment Group, CSIR-Indian Institute of Toxicology Research (CSIR-IITR), Vishvigyan Bhavan, 31, Mahatma Gandhi Marg, Lucknow 226001, Uttar Pradesh, India.,the Academy of Scientific and Innovative Research (AcSIR), CSIR-IITR Lucknow Campus, Lucknow 226001, Uttar Pradesh, India
| | - Swati Agarwal
- From the Developmental Toxicology Laboratory, Systems Toxicology and Health Risk Assessment Group, CSIR-Indian Institute of Toxicology Research (CSIR-IITR), Vishvigyan Bhavan, 31, Mahatma Gandhi Marg, Lucknow 226001, Uttar Pradesh, India.,the Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, and
| | - Shashi Kant Tiwari
- From the Developmental Toxicology Laboratory, Systems Toxicology and Health Risk Assessment Group, CSIR-Indian Institute of Toxicology Research (CSIR-IITR), Vishvigyan Bhavan, 31, Mahatma Gandhi Marg, Lucknow 226001, Uttar Pradesh, India.,the Department of Pediatrics, University of California San Diego, La Jolla, California 92093
| | - Rajnish Kumar Chaturvedi
- From the Developmental Toxicology Laboratory, Systems Toxicology and Health Risk Assessment Group, CSIR-Indian Institute of Toxicology Research (CSIR-IITR), Vishvigyan Bhavan, 31, Mahatma Gandhi Marg, Lucknow 226001, Uttar Pradesh, India, .,the Academy of Scientific and Innovative Research (AcSIR), CSIR-IITR Lucknow Campus, Lucknow 226001, Uttar Pradesh, India
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7
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Gómez-Giménez B, Felipo V, Cabrera-Pastor A, Agustí A, Hernández-Rabaza V, Llansola M. Developmental Exposure to Pesticides Alters Motor Activity and Coordination in Rats: Sex Differences and Underlying Mechanisms. Neurotox Res 2017; 33:247-258. [DOI: 10.1007/s12640-017-9823-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Revised: 09/13/2017] [Accepted: 09/20/2017] [Indexed: 12/01/2022]
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Li L, Du Y, Ju F, Ma S, Zhang S. Calcium plays a key role in paraoxon-induced apoptosis in EL4 cells by regulating both endoplasmic reticulum- and mitochondria-associated pathways. Toxicol Mech Methods 2016; 26:211-20. [PMID: 26998625 DOI: 10.3109/15376516.2016.1156796] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
CONTEXT AND OBJECTIVE Paraoxon (POX) is one of the most toxic organophosphorus pesticides, but its toxic mechanisms associated with apoptosis remain unclear. The aim of this study was to investigate calcium-associated mechanisms in POX-induced apoptosis in EL4 cells. MATERIALS AND METHODS EL4 cells were exposed to POX for 0-16 h. EGTA was used to chelate Ca(2+ ) in extracellular medium, and heparin and procaine were used to inhibit Ca(2+ )efflux from the endoplasmic reticulum (ER). Z-ATAD-FMK was used to inhibit caspase-12 activity. The apoptotic rate assay, western blotting and immunocytochemistry (ICC) were used to reveal the mechanisms of POX-induced apoptosis. RESULTS AND DISCUSSION POX significantly increased the expression and activation of caspase-12 and caspase-3, enhanced expression of calpain 1 and calpain 2, and induced the release of cyt c, but did not change the expression of Grp 78. Inhibiting caspase-12 activity alleviated POX-induced upregulation of calpain 1 and caspase-3, promoted POX-induced upregulation of calpain 2, and reduced POX-induced cyt c release, suggesting that there was a cross-talk between the ER-associated pathway and mitochondria-associated apoptotic signals. Attenuating intracellular calcium concentration with EGTA, heparin or procaine decreased POX-induced upregulation of calpain 1, calpain 2, caspase-12 and caspase-3, and reduced POX-induced cyt c release. After pretreatment with EGTA or procaine, POX significantly promoted expression of Grp 78. CONCLUSIONS Calcium played a key role in POX-induced apoptosis in EL4 cells by regulating both ER- and mitochondria-associated pathways. The cross-talk of ER- and mitochondria-associated pathways was accomplished through calcium signal.
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Affiliation(s)
- Lan Li
- a Gansu Key Laboratory of Biomonitoring and Bioremediation for Environmental Pollution, School of Life Sciences, Lanzhou University , Lanzhou , People's Republic of China
| | - Yi Du
- a Gansu Key Laboratory of Biomonitoring and Bioremediation for Environmental Pollution, School of Life Sciences, Lanzhou University , Lanzhou , People's Republic of China
| | - Furong Ju
- a Gansu Key Laboratory of Biomonitoring and Bioremediation for Environmental Pollution, School of Life Sciences, Lanzhou University , Lanzhou , People's Republic of China
| | - Shunxiang Ma
- a Gansu Key Laboratory of Biomonitoring and Bioremediation for Environmental Pollution, School of Life Sciences, Lanzhou University , Lanzhou , People's Republic of China
| | - Shengxiang Zhang
- a Gansu Key Laboratory of Biomonitoring and Bioremediation for Environmental Pollution, School of Life Sciences, Lanzhou University , Lanzhou , People's Republic of China
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Adebayo OL, Sandhir R, Adenuga GA. Protective roles of selenium and zinc against postnatal protein‐undernutrition‐induced alterations in Ca
2+
‐homeostasis leading to cognitive deficits in Wistar rats. Int J Dev Neurosci 2015; 43:1-7. [DOI: 10.1016/j.ijdevneu.2015.03.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2015] [Revised: 02/26/2015] [Accepted: 03/13/2015] [Indexed: 12/06/2022] Open
Affiliation(s)
- Olusegun L. Adebayo
- Department of Chemical SciencesCollege of Natural SciencesRedeemer's UniversityP.M.B. 230EdeOsun StateNigeria
- Department of Biochemistry, Basic Medical Science BuildingPanjab UniversityChandigarh160014India
- Department of Biochemistry, Faculty of Basic Medical SciencesOlabisi Onabanjo UniversityP.M.B. 2005, Remo CampusIkenneOgun StateNigeria
| | - Rajat Sandhir
- Department of Biochemistry, Basic Medical Science BuildingPanjab UniversityChandigarh160014India
| | - Gbenga A. Adenuga
- Department of Biochemistry, Faculty of Basic Medical SciencesOlabisi Onabanjo UniversityP.M.B. 2005, Remo CampusIkenneOgun StateNigeria
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10
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Singhal K, Sandhir R. L-type calcium channel blocker ameliorates diabetic encephalopathy by modulating dysregulated calcium homeostasis. J Neurosci Res 2014; 93:296-308. [DOI: 10.1002/jnr.23478] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2014] [Revised: 07/20/2014] [Accepted: 08/07/2014] [Indexed: 01/02/2023]
Affiliation(s)
- Kirti Singhal
- Department of Biochemistry; Panjab University; Chandigarh India
| | - Rajat Sandhir
- Department of Biochemistry; Panjab University; Chandigarh India
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11
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Curcumin supplementation improves mitochondrial and behavioral deficits in experimental model of chronic epilepsy. Pharmacol Biochem Behav 2014; 125:55-64. [PMID: 25117510 DOI: 10.1016/j.pbb.2014.08.001] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Revised: 07/28/2014] [Accepted: 08/02/2014] [Indexed: 01/06/2023]
Abstract
The present study was aimed to investigate the potential beneficial effect of curcumin, a polyphenol with pleiotropic properties, on mitochondrial dysfunctions, oxidative stress and cognitive deficits in a kindled model of epilepsy. Kindled epilepsy was induced in rats by administering a sub-convulsive dose of pentylenetetrazole (PTZ, 40 mg/kg body weight) every alternate day for 30 days. PTZ administered rats exhibited marked cognitive deficits assessed using active and passive avoidance tasks. This was accompanied by a significant decrease in NADH:cytochrome-c reductase (complex I) and cytochrome-c oxidase (complex IV) activities along with an increase in ROS, lipid peroxidation and protein carbonyls. The levels of glutathione also decreased in the cortex and hippocampus. Electron micrographs revealed disruption of mitochondrial membrane integrity with distorted cristae in PTZ treated animals. Histopathological examination showed pyknotic nuclei and cell loss in the hippocampus as well as in the cortex of PTZ treated animals. Curcumin administration at a dose of 100 mg/kg, p.o. throughout the treatment paradigm was able to ameliorate cognitive deficits with no significant effect on seizure score. Curcumin was able to restore the activity of mitochondrial complexes. In addition, significant reduction in ROS generation, lipid peroxidation and protein carbonyls was observed in PTZ animals supplemented with curcumin. Moreover, glutathione levels were also restored in PTZ treated rats supplemented with curcumin. Curcumin protected mitochondria from seizure induced structural alterations. Further, the curcumin supplemented PTZ rats had normal cell morphology and reduced cell loss. These results suggest that curcumin supplementation has potential to prevent mitochondrial dysfunctions and oxidative stress with improved cognitive functions in a chronic model of epilepsy.
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Krieg EF. The relationships between pesticide metabolites and neurobehavioral test performance in the third National Health and Nutrition Examination Survey. ARCHIVES OF ENVIRONMENTAL & OCCUPATIONAL HEALTH 2013; 68:39-46. [PMID: 23298423 DOI: 10.1080/19338244.2011.633125] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Regression analysis was used to estimate and test for relationships between urinary pesticide metabolites and neurobehavioral test performance in adults, 20 to 59 years old, participating in the third National Health and Nutrition Examination Survey. The 12 pesticide metabolites included 2 naphthols, 8 phenols, a phenoxyacetic acid, and a pyridinol. The 3 neurobehavioral tests included in the survey were simple reaction time, symbol-digit substitution, and serial digit learning. As the 2,4-dichlorophenol, 2,5-dichlorophenol, and the pentachlorophenol concentrations increased, performance on the serial digit learning test improved. As the 2,5-dichlorophenol concentration increased, performance on the symbol-digit substitution test improved. At low concentrations, the parent compounds of these metabolites may act at acetylcholine and γ-aminobutyric acid synapses in the central nervous system to improve neurobehavioral test performance.
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Affiliation(s)
- Edward F Krieg
- National Institute for Occupational Safety and Health, Cincinnati, OH 45226, USA.
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13
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Mishra D, Tiwari SK, Agarwal S, Sharma VP, Chaturvedi RK. Prenatal carbofuran exposure inhibits hippocampal neurogenesis and causes learning and memory deficits in offspring. Toxicol Sci 2012; 127:84-100. [PMID: 22240977 DOI: 10.1093/toxsci/kfs004] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Neurogenesis is a process of generation of new neurons in the hippocampus and associated with learning and memory. Carbofuran, a carbamate pesticide, elicits several neurochemical, neurophysiological, and neurobehavioral deficits. We evaluated whether chronic prenatal oral exposure of carbofuran during gestational days 7-21 alters postnatal hippocampal neurogenesis at postnatal day 21. We found carbofuran treatment significantly decreased bromodeoxyuridine (BrdU) positive cell proliferation and long-term survival in the hippocampus only but not in the cerebellum. We observed a reduced number of transcription factor SOX-2 and glial fibrillary acidic protein (GFAP) colabeled cells, decreased nestin messenger RNA (mRNA) expression, and decreased histone-H3 phosphorylation following carbofuran treatment, suggesting a decreased pool of neural progenitor cells (NPC). Colocalization of BrdU with doublecortin (DCX), neuronal nuclei (NeuN), and GFAP suggested decreased neuronal differentiation and increased glial differentiation by carbofuran. The number of DCX(+) and NeuN(+) neurons, NeuN protein levels, and fibers length of DCX(+) neurons were decreased by carbofuran. Carbofuran caused a significant downregulation of mRNA expression of the neurogenic genes/transcription factors such as neuregulin, neurogenin, and neuroD1 and upregulation of the gliogenic gene Stat3. Carbofuran exposure led to increased BrdU/caspase 3 colabeled cells, an increased number of degenerative neurons and profound deficits in learning and memory processes. The number and size of primary neurospheres derived from the hippocampus of carbofuran-treated rats were decreased. These results suggest that early gestational carbofuran exposure diminishes neurogenesis, reduces the NPC pool, produces neurodegeneration in the hippocampus, and causes cognitive impairments in rat offspring.
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Affiliation(s)
- Divya Mishra
- Developmental Toxicology Division, Systems Toxicology Group, Council of Scientific and Industrial Research-Indian Institute of Toxicology Research, Lucknow-226001, India
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