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de Souza Prestes A, Vargas JLS, Dos Santos MM, Druzian GT, da Rocha JT, Aschner M, Barbosa NV. EtHg is more toxic than MeHg to human peripheral blood mononuclear cells: Involvement of apoptotic, mitochondrial, oxidative and proliferative parameters. Biochim Biophys Acta Gen Subj 2023; 1867:130446. [PMID: 37619690 DOI: 10.1016/j.bbagen.2023.130446] [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: 04/10/2023] [Revised: 08/15/2023] [Accepted: 08/21/2023] [Indexed: 08/26/2023]
Abstract
BACKGROUND Methylmercury (MeHg) and ethylmercury (EtHg) are potent toxicants affecting the environment and human healthy. In this way, the present study aimed to investigate and compare the effects of MeHg and EtHg exposure on human peripheral blood mononuclear cells (PBMCs), which are critical components of the mammalian immune system. METHODS PBMCs were exposed to 2.5 μM MeHg or 2.5 μM EtHg. The number of cells and incubation times varied according to each assay. After exposures, the PBMCs were subjected to different evaluations, including cell viability, morphological aspects, cell cycle phases, indices of apoptosis and necrosis, reactive species (RS) production, and mitochondrial functionality. RESULTS PBMCs exposed to EtHg were characterized by decreased viability and size, increased granularity, RS production, and apoptotic indexes accompanied by an intensification of Sub-G1 and reduction in G0-G1 cell cycle phases. Preceding these effects, we found mitochondrial dysfunctions, namely a reduction in the electron transport system related to mitochondrial complex I. In contrast, PBMCs exposed to MeHg showed only reduced viability. By ICP-MS, we found that PBMCs treated with EtHg accumulated Hg + levels ∼1.8-fold greater than MeHg-exposed cells. CONCLUSIONS AND SIGNIFICANCE Taken together, our findings provide important insights about mercury immunotoxicity, showing that EtHg is more immunotoxic to human PBMCs than MeHg.
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Affiliation(s)
- Alessandro de Souza Prestes
- Department of Biochemistry and Molecular Biology, Federal University of Santa Maria, Santa Maria, RS, Brazil.
| | - João Luis Souza Vargas
- Department of Biochemistry and Molecular Biology, Federal University of Santa Maria, Santa Maria, RS, Brazil
| | - Matheus Mülling Dos Santos
- Department of Biochemistry and Molecular Biology, Federal University of Santa Maria, Santa Maria, RS, Brazil
| | | | - João Teixeira da Rocha
- Department of Biochemistry and Molecular Biology, Federal University of Santa Maria, Santa Maria, RS, Brazil
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Nilda Vargas Barbosa
- Department of Biochemistry and Molecular Biology, Federal University of Santa Maria, Santa Maria, RS, Brazil.
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Sasaki S, Negishi T, Tsuzuki T, Yukawa K. Methylmercury-induced reactive oxygen species-dependent and independent dysregulation of MAP kinase-related signaling pathway in cultured normal rat cerebellar astrocytes. Toxicology 2023; 487:153463. [PMID: 36813253 DOI: 10.1016/j.tox.2023.153463] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Revised: 02/17/2023] [Accepted: 02/17/2023] [Indexed: 02/22/2023]
Abstract
Methylmercury (MeHg), a global environmental pollutant, could seriously damage the central nervous system (CNS) and cause neurological disorders such as cerebellar symptoms. Although numerous studies have revealed detailed toxicity mechanisms of MeHg in neurons, toxicity in astrocytes is barely known. Here, we tried to shed light on the toxicity mechanisms of MeHg exposure in cultured normal rat cerebellar astrocytes (NRA), focusing on the involvement of reactive oxygen species (ROS) in MeHg toxicity by assessing the effects of major antioxidants Trolox, a free-radical scavenger, N-acetyl-L-cysteine (NAC), a potent thiol-containing antioxidant, and glutathione (GSH), an endogenous thiol-containing antioxidant. Exposure to MeHg at just approximately 2 µM for 96 h increased cell viability, which was accompanied by the increase in intracellular ROS level and at ≥ 5 µM induced significant cell death and lowered ROS level. Trolox and NAC suppressed 2 µM MeHg-induced increases in cell viability and ROS level corresponding to control, although GSH with 2 µM MeHg induced significant cell death and ROS increase. On the contrary, against 4 µM MeHg-induced cell loss and ROS decrease, NAC inhibited both cell loss and ROS decrease, Trolox inhibited cell loss and further enhanced ROS decrease, and GSH moderately inhibited cell loss and increased ROS level above the control level. MeHg-induced oxidative stress was suggested by increases in the protein expression levels of heme oxygenase-1 (HO-1), Hsp70, and Nrf2, except for the decrease in SOD-1 and no change in catalase. Furthermore, MeHg exposure dose-dependently induced increases in the phosphorylation of MAP kinases (ERK1/2, p38MAPK, and SAPK/JNK) and phosphorylation and/or expression levels of transcription factors (CREB, c-Jun, and c-Fos) in NRA. NAC successfully suppressed 2 µM MeHg-induced alterations in all of the above-mentioned MeHg-responsive factors, whereas Trolox suppressed some MeHg-responsive factors but failed to suppress MeHg-induced increases in the protein expression levels of HO-1 and Hsp70 and increase in p38MAPK phosphorylation. Protein expression analyses in NRA exposed to 2 µM MeHg and GSH were excluded because of devastating cell death. These results suggested that MeHg could induce aberrant NRA activation, and ROS must be substantially involved in the toxicity mechanism of MeHg in NRA; however, other factors should be assumed.
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Affiliation(s)
- Shoto Sasaki
- Department of Physiology, Graduate School of Pharmacy, Meijo University, 150 Yagotoyama, Tempaku-ku, Nagoya-shi, Aichi 468-8503, Japan
| | - Takayuki Negishi
- Department of Physiology, Graduate School of Pharmacy, Meijo University, 150 Yagotoyama, Tempaku-ku, Nagoya-shi, Aichi 468-8503, Japan; Department of Physiology, Faculty of Pharmacy, Meijo University, 150 Yagotoyama, Tempaku-ku, Nagoya-shi, Aichi 468-8503, Japan.
| | - Takamasa Tsuzuki
- Department of Physiology, Faculty of Pharmacy, Meijo University, 150 Yagotoyama, Tempaku-ku, Nagoya-shi, Aichi 468-8503, Japan
| | - Kazunori Yukawa
- Department of Physiology, Graduate School of Pharmacy, Meijo University, 150 Yagotoyama, Tempaku-ku, Nagoya-shi, Aichi 468-8503, Japan; Department of Physiology, Faculty of Pharmacy, Meijo University, 150 Yagotoyama, Tempaku-ku, Nagoya-shi, Aichi 468-8503, Japan
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Bjørklund G, Antonyak H, Polishchuk A, Semenova Y, Lesiv M, Lysiuk R, Peana M. Effect of methylmercury on fetal neurobehavioral development: an overview of the possible mechanisms of toxicity and the neuroprotective effect of phytochemicals. Arch Toxicol 2022; 96:3175-3199. [PMID: 36063174 DOI: 10.1007/s00204-022-03366-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2022] [Accepted: 08/17/2022] [Indexed: 11/25/2022]
Abstract
Methylmercury (MeHg) is a global environmental pollutant with neurotoxic effects. Exposure to MeHg via consumption of seafood and fish can severely impact fetal neurobehavioral development even when MeHg levels in maternal blood are as low as about 5 μg/L, which the mother tolerates well. Persistent motor dysfunctions and cognitive deficits may result from trans-placental exposure. The present review summarizes current knowledge on the mechanisms of MeHg toxicity during the period of nervous system development. Although cerebellar Purkinje cells are MeHg targets, the actions of MeHg on thiol components in the neuronal cytoskeleton as well as on mitochondrial enzymes and induction of disturbances of glutamate signaling can impair extra-cerebellar functions, also at levels well tolerated by adult individuals. Numerous herbal substances possess neuroprotective effects, predominantly represented by natural polyphenolic molecules that might be utilized to develop natural drugs to alleviate neurotoxicity symptoms caused by MeHg or other Hg compounds.
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Affiliation(s)
- Geir Bjørklund
- Council for Nutritional and Environmental Medicine, Toften 24, 8610, Mo i Rana, Norway.
| | | | | | | | - Marta Lesiv
- Ivan Franko National University of Lviv, Lviv, Ukraine
| | - Roman Lysiuk
- Danylo Halytsky Lviv National Medical University, Lviv, Ukraine
- CONEM Ukraine Life Science Research Group, Danylo Halytsky Lviv National Medical University, Lviv, Ukraine
| | - Massimiliano Peana
- Department of Chemical, Physics, Mathematics and Natural Sciences, University of Sassari, Sassari, Italy
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4
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Shandilya A, Mehan S, Kumar S, Sethi P, Narula AS, Alshammari A, Alharbi M, Alasmari AF. Activation of IGF-1/GLP-1 Signalling via 4-Hydroxyisoleucine Prevents Motor Neuron Impairments in Experimental ALS-Rats Exposed to Methylmercury-Induced Neurotoxicity. Molecules 2022; 27:3878. [PMID: 35745001 PMCID: PMC9228431 DOI: 10.3390/molecules27123878] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2022] [Revised: 06/13/2022] [Accepted: 06/14/2022] [Indexed: 12/11/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a severe adult motor neuron disease that causes progressive neuromuscular atrophy, muscle wasting, weakness, and depressive-like symptoms. Our previous research suggests that mercury levels are directly associated with ALS progression. MeHg+-induced ALS is characterised by oligodendrocyte destruction, myelin basic protein (MBP) depletion, and white matter degeneration, leading to demyelination and motor neuron death. The selection of MeHg+ as a potential neurotoxicant is based on our evidence that it has been connected to the development of ALS-like characteristics. It causes glutamate-mediated excitotoxicity, calcium-dependent neurotoxicity, and an ALS-like phenotype. Dysregulation of IGF-1/GLP-1 signalling has been associated with ALS progression. The bioactive amino acid 4-hydroxyisoleucine (HI) from Trigonella foenum graecum acts as an insulin mimic in rodents and increases insulin sensitivity. This study examined the neuroprotective effects of 4-HI on MeHg+-treated adult Wistar rats with ALS-like symptoms, emphasising brain IGF1/GLP-1 activation. Furthermore, we investigated the effect of 4-HI on MBP levels in rat brain homogenate, cerebrospinal fluid (CSF), blood plasma, and cell death indicators such as caspase-3, Bax, and Bcl-2. Rats were assessed for muscular strength, locomotor deficits, depressed behaviour, and spatial learning in the Morris water maze (MWM) to measure neurobehavioral abnormalities. Doses of 4-HI were given orally for 42 days in the MeHg+ rat model at 50 mg/kg or 100 mg/kg to ameliorate ALS-like neurological dysfunctions. Additionally, neurotransmitters and oxidative stress markers were examined in rat brain homogenates. Our findings suggest that 4-HI has neuroprotective benefits in reducing MeHg+-induced behavioural, neurochemical, and histopathological abnormalities in ALS-like rats exposed to methylmercury.
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Affiliation(s)
- Ambika Shandilya
- Division of Neuroscience, Department of Pharmacology, ISF College of Pharmacy, Moga 142001, Punjab, India; (A.S.); (S.K.); (P.S.)
| | - Sidharth Mehan
- Division of Neuroscience, Department of Pharmacology, ISF College of Pharmacy, Moga 142001, Punjab, India; (A.S.); (S.K.); (P.S.)
| | - Sumit Kumar
- Division of Neuroscience, Department of Pharmacology, ISF College of Pharmacy, Moga 142001, Punjab, India; (A.S.); (S.K.); (P.S.)
| | - Pranshul Sethi
- Division of Neuroscience, Department of Pharmacology, ISF College of Pharmacy, Moga 142001, Punjab, India; (A.S.); (S.K.); (P.S.)
| | - Acharan S. Narula
- Narula Research, LLC, 107 Boulder Bluff, Chapel Hill, NC 27516, USA;
| | - Abdulrahman Alshammari
- Department of Pharmacology and Toxicology, College of Pharmacy, King Saud University, Post Box 2455, Riyadh 11451, Saudi Arabia; (A.A.); (M.A.); (A.F.A.)
| | - Metab Alharbi
- Department of Pharmacology and Toxicology, College of Pharmacy, King Saud University, Post Box 2455, Riyadh 11451, Saudi Arabia; (A.A.); (M.A.); (A.F.A.)
| | - Abdullah F. Alasmari
- Department of Pharmacology and Toxicology, College of Pharmacy, King Saud University, Post Box 2455, Riyadh 11451, Saudi Arabia; (A.A.); (M.A.); (A.F.A.)
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5
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Kim R, Kim JW, Lee SJ, Bae GU. Ginsenoside Rg3 protects glucocorticoid‑induced muscle atrophy in vitro through improving mitochondrial biogenesis and myotube growth. Mol Med Rep 2022; 25:94. [PMID: 35059739 PMCID: PMC8809047 DOI: 10.3892/mmr.2022.12610] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Accepted: 12/02/2021] [Indexed: 02/07/2023] Open
Abstract
Ginsenoside Rg3 (Rg3), amplified by iterative heating processing with fresh ginseng, has a broad range of pharmacological activities and improves mitochondrial biogenesis in skeletal muscle. However, thus far no study has examined how Rg3 affects myotube growth or muscle atrophy, to the best of the authors' knowledge. The present study was conducted to examine the myogenic effect of Rg3 on dexamethasone (DEX)‑induced myotube atrophy and the underlying molecular mechanisms. Rg3 activated Akt/mammalian target of rapamycin signaling to prevent DEX‑induced myotube atrophy thereby stimulating the expression of muscle‑specific genes, including myosin heavy chain and myogenin, and suppressing muscle‑specific ubiquitin ligases as demonstrated by immunoblotting and immunostaining assays. Furthermore, Rg3 efficiently prevented DEX‑triggered mitochondrial dysfunction of myotubes through peroxisome proliferator‑activated receptor‑γ coactivator1α activities and its mitochondrial biogenetic transcription factors, nuclear respiratory factor‑1 and mitochondrial transcription factor A. These were confirmed by immunoblotting, luciferase assays, RT‑qPCR and mitochondrial analysis measuring the levels of ROS, ATP and membrane potential. By providing a mechanistic insight into the effect of Rg3 on myotube atrophy, the present study suggested that Rg3 has potential as a therapeutic or nutraceutical remedy to intervene in muscle aging or diseases including cancer cachexia.
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Affiliation(s)
- Ryuni Kim
- Drug Information Research Institute, College of Pharmacy, Sookmyung Women's University, Seoul 04310, Republic of Korea
| | - Jee Won Kim
- Drug Information Research Institute, College of Pharmacy, Sookmyung Women's University, Seoul 04310, Republic of Korea
| | - Sang-Jin Lee
- Research Institute of Aging Related Disease, AniMusCure Inc., Suwon 16419, Republic of Korea
| | - Gyu-Un Bae
- Drug Information Research Institute, College of Pharmacy, Sookmyung Women's University, Seoul 04310, Republic of Korea
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Ferrer B, Suresh H, Tinkov AA, Santamaria A, Rocha JB, Skalny AV, Bowman AB, Aschner M. Ghrelin attenuates methylmercury-induced oxidative stress in neuronal cells. Mol Neurobiol 2022; 59:2098-2115. [PMID: 35040042 DOI: 10.1007/s12035-022-02726-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 12/30/2021] [Indexed: 11/28/2022]
Abstract
Methylmercury (MeHg) is a global pollutant, which can cause damage to the central nervous system at both high-acute and chronic-low exposures, especially in vulnerable populations, such as children and pregnant women. Nowadays, acute-high poisoning is rare. However, chronic exposure to low MeHg concentrations via fish consumption remains a health concern. Current therapeutic strategies for MeHg poisoning are based on the use of chelators. However, these therapies have limited efficacy. Ghrelin is a gut hormone with an important role in regulating physiologic processes. It has been reported that ghrelin plays a protective role against the toxicity of several xenobiotics. Here, we explored the role of ghrelin as a putative protector against MeHg-induced oxidative stress. Our data show that ghrelin was able to ameliorate MeHg-induced reactive oxygen species (ROS) production in primary neuronal hypothalamic and hippocampal cultures. An analogous effect was observed in mouse hypothalamic neuronal GT 1-7 cells. Using this model, our novel findings show that antioxidant protection of ghrelin against MeHg is mediated by glutathione upregulation and induction of the NRF2/NQO1 pathway.
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Affiliation(s)
- Beatriz Ferrer
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY, 10461, USA.
| | - Harshini Suresh
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY, 10461, USA
| | - Alexey A Tinkov
- Laboratory of Molecular Dietetics, IM Sechenov First Moscow State Medical University, Moscow, Russia.,Laboratory of Ecobiomonitoring and Quality Control, Yaroslavl State University, Yaroslavl, Russia
| | - Abel Santamaria
- Laboratorio de Aminoácidos Excitadores/Laboratorio de Neurofarmacología Molecular Y Nanotecnología, Instituto Nacional de Neurología Y Neurocirugía, 14269, Mexico City, Mexico
| | - João Batista Rocha
- Departamento de Bioquímica E Biologia Molecular, Universidade Federal de Santa Maria, Santa Maria, Rio Grande do Sul, Brazil
| | - Anatoly V Skalny
- World-Class Research Center "Digital Biodesign and Personalized Healthcare", IM Sechenov First Moscow State Medical University (Sechenov University), 119435, Moscow, Russia.,Department of Bioelementology, KG Razumovsky Moscow State University of Technologies and Management, Moscow, Russia
| | - Aaron B Bowman
- School of Health Sciences, Purdue University, West Lafayette, IN, USA
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY, 10461, USA. .,Laboratory of Molecular Dietetics, IM Sechenov First Moscow State Medical University, Moscow, Russia.
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7
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Revisiting Astrocytic Roles in Methylmercury Intoxication. Mol Neurobiol 2021; 58:4293-4308. [PMID: 33990914 DOI: 10.1007/s12035-021-02420-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Accepted: 05/04/2021] [Indexed: 02/06/2023]
Abstract
Intoxication by heavy metals such as methylmercury (MeHg) is recognized as a global health problem, with strong implications in central nervous system pathologies. Most of these neuropathological conditions involve vascular, neurotransmitter recycling, and oxidative balance disruption leading to accelerated decline in fine balance, and learning, memory, and visual processes as main outcomes. Besides neurons, astrocytes are involved in virtually all the brain processes and perform important roles in neurological response following injuries. Due to astrocytes' strategic functions in brain homeostasis, these cells became the subject of several studies on MeHg intoxication. The most heterogenous glial cells, astrocytes, are composed of plenty of receptors and transporters to dialogue with neurons and other cells and to monitor extracellular environment responding tightly through fluctuation of cytosolic ions. The overall toxicity of MeHg might be determined on the basis of the balance between MeHg-mediated injury to neurons and protective responses from astrocytes. Although the role of neurons in MeHg intoxication is relatively well-established, the role of the astrocytes is only beginning to be understood. In this review, we update the information on astroglial modulation of the MeHg-induced neurotoxicity, providing remarks on their protective and deleterious roles and insights for future studies.
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8
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Ullah I, Zhao L, Hai Y, Fahim M, Alwayli D, Wang X, Li H. "Metal elements and pesticides as risk factors for Parkinson's disease - A review". Toxicol Rep 2021; 8:607-616. [PMID: 33816123 PMCID: PMC8010213 DOI: 10.1016/j.toxrep.2021.03.009] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 03/07/2021] [Accepted: 03/09/2021] [Indexed: 02/07/2023] Open
Abstract
Essential metals including iron (Fe) and manganese (Mn) with known physiological functions in human body play an important role in cell homeostasis. Excessive exposure to these essential as well as non-essential metals including mercury (Hg) and Aluminum (Al) may contribute to pathological conditions, including PD. Each metal could be toxic through specific pathways. Epidemiological evidences from occupational and ecological studies besides various in vivo and in vitro studies have revealed the possible pathogenic role and neurotoxicity of different metals. Pesticides are substances that aim to mitigate the harm done by pests to plants and crops, and are extensively used to boost agricultural production. This review provides an outline of our current knowledge on the possible association between metals and PD. We have discussed the potential association between these two, furthermore the chemical properties, biological and toxicological aspects as well as possible mechanisms of Fe, Mn, Cu, Zn, Al, Ca, Pb, Hg and Zn in PD pathogenesis. In addition, we review recent evidence on deregulated microRNAs upon pesticide exposure and possible role of deregulated miRNA and pesticides to PD pathogenesis.
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Affiliation(s)
- Inam Ullah
- School of Life Sciences, Lanzhou University, China
| | - Longhe Zhao
- School of Pharmacy, Lanzhou University, China
| | - Yang Hai
- School of Pharmacy, Lanzhou University, China
| | | | | | - Xin Wang
- School of Pharmacy, Lanzhou University, China
| | - Hongyu Li
- School of Life Sciences, Lanzhou University, China
- School of Pharmacy, Lanzhou University, China
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Kim R, Kim H, Im M, Park SK, Han HJ, An S, Kang JS, Lee SJ, Bae GU. BST204 Protects Dexamethasone-Induced Myotube Atrophy through the Upregulation of Myotube Formation and Mitochondrial Function. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph18052367. [PMID: 33804338 PMCID: PMC7957540 DOI: 10.3390/ijerph18052367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Revised: 02/19/2021] [Accepted: 02/23/2021] [Indexed: 10/31/2022]
Abstract
BST204 is a purified ginseng dry extract that has an inhibitory effect on lipopolysaccharide-induced inflammatory responses, but its effect on muscle atrophy is yet to be investigated. In this study, C2C12 myoblasts were induced to differentiate for three days followed by the treatment of dexamethasone (DEX), a corticosteroid drug, with vehicle or BST204 for one day and subjected to immunoblotting, immunocytochemistry, qRT-PCR and biochemical analysis for mitochondrial function. BST204 alleviates the myotube atrophic effect mediated by DEX via the activation of protein kinase B/mammalian target of rapamycin (Akt/mTOR) signaling. Through this pathway, BST204 suppresses the expression of muscle-specific E3 ubiquitin ligases contributing to the enhanced myotube formation and enlarged myotube diameter in DEX-treated myotubes. In addition, BST204 treatment significantly decreases the mitochondrial reactive oxygen species production in DEX-treated myotubes. Furthermore, BST204 improves mitochondrial function by upregulating the expression of peroxisome proliferator-activated receptor-γ coactivator-1α (PGC1α) in DEX-induced myotube atrophy. This study provides a mechanistic insight into the effect of BST204 on DEX-induced myotube atrophy, suggesting that BST204 has protective effects against the toxicity of a corticosteroid drug in muscle and promising potential as a nutraceutical remedy for the treatment of muscle weakness and atrophy.
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Affiliation(s)
- Ryuni Kim
- Research Institute of Pharmaceutical Science, College of Pharmacy, Sookmyung Women’s University, Seoul 04310, Korea;
| | - Hyebeen Kim
- Molecular Cell Biology, Single Cell Network Research Center, School of Medicine, Sungkyunkwan University, Suwon 16419, Korea; (H.K.); (S.A.); (J.-S.K.)
| | - Minju Im
- Green Cross Wellbeing Co., Ltd., Seongnam 13595, Korea; (M.I.); (S.K.P.); (H.J.H.)
| | - Sun Kyu Park
- Green Cross Wellbeing Co., Ltd., Seongnam 13595, Korea; (M.I.); (S.K.P.); (H.J.H.)
| | - Hae Jung Han
- Green Cross Wellbeing Co., Ltd., Seongnam 13595, Korea; (M.I.); (S.K.P.); (H.J.H.)
| | - Subin An
- Molecular Cell Biology, Single Cell Network Research Center, School of Medicine, Sungkyunkwan University, Suwon 16419, Korea; (H.K.); (S.A.); (J.-S.K.)
| | - Jong-Sun Kang
- Molecular Cell Biology, Single Cell Network Research Center, School of Medicine, Sungkyunkwan University, Suwon 16419, Korea; (H.K.); (S.A.); (J.-S.K.)
- Research Institute of Aging-Related Disease, AniMusCure Inc., Suwon 16419, Korea
| | - Sang-Jin Lee
- Research Institute of Pharmaceutical Science, College of Pharmacy, Sookmyung Women’s University, Seoul 04310, Korea;
- Research Institute of Aging-Related Disease, AniMusCure Inc., Suwon 16419, Korea
- Correspondence: (S.-J.L.); (G.-U.B.)
| | - Gyu-Un Bae
- Research Institute of Pharmaceutical Science, College of Pharmacy, Sookmyung Women’s University, Seoul 04310, Korea;
- Correspondence: (S.-J.L.); (G.-U.B.)
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10
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Muniroh M. Methylmercury-induced pro-inflammatory cytokines activation and its preventive strategy using anti-inflammation N-acetyl-l-cysteine: a mini-review. REVIEWS ON ENVIRONMENTAL HEALTH 2020; 35:233-238. [PMID: 32710722 DOI: 10.1515/reveh-2020-0026] [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: 02/24/2020] [Accepted: 06/09/2020] [Indexed: 06/11/2023]
Abstract
The exposure of methylmercury (MeHg) has become a public health concern because of its neurotoxic effect. Various neurological symptoms were detected in Minamata disease patients, who got intoxicated by MeHg, including paresthesia, ataxia, gait disturbance, sensory disturbances, tremors, visual, and hearing impairments, indicating that MeHg could pass the blood-brain barrier (BBB) and cause impairment of neurons and other brain cells. Previous studies have reported some expected mechanisms of MeHg-induced neurotoxicity including the neuroinflammation pathway. It was characterized by the up-regulation of numerous pro-inflammatory cytokines expression. Therefore, the use of anti-inflammatories such as N-acetyl-l-cysteine (NAC) may act as a preventive compound to protect the brain from MeHg harmful effects. This mini-review will explain detailed information on MeHg-induced pro-inflammatory cytokines activation as well as possible preventive strategies using anti-inflammation NAC to protect brain cells, particularly in in vivo and in vitro studies.
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Affiliation(s)
- Muflihatul Muniroh
- Department of Physiology, Faculty of Medicine Diponegoro University, Semarang, Central Java, 50275, Indonesia
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Fu X, Yang X, Du X, Cui Q. Deciphering the possible role of H2O2 in methylmercury-induced neurotoxicity in Xenopus laevis. Mol Cell Toxicol 2020. [DOI: 10.1007/s13273-020-00082-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Abstract
Backgrounds
Methylmercury (MeHg) is regarded as a developmental neurotoxicant but the detailed mechanism remains not completely clear.
Methods
The Xenopus laevis embryos were exposed to methylmercury chloride and the expression of neurodevelopment and oxidative stress genes was detected by qRT-PCR or Western blotting. PC12 cells were exposed to various levels of H2O2, and then cell cycle, neurite length, neurodevelopment-related genes, protein expression of apoptosis and autophagy were detected.
Results
The genes of neurodevelopment and oxidative stress were disrupted by methylmercury chloride and H2O2 were increased interestingly in X. laevis embryos. Then, PC12 cells were exposed to H2O2 and the results showed the cell cycle, neurite length, and neurodevelopment-related genes, the proteins apoptosis and autophagy were changed.
Conclusion
These results supported the idea that neurodevelopment-related gene expression was regulated by oxidative stress and that apoptosis and autophagy pathways were activated by H2O2 and involved in methylmercury neurotoxicity.
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Yang L, Zhang Y, Wang F, Luo Z, Guo S, Strähle U. Toxicity of mercury: Molecular evidence. CHEMOSPHERE 2020; 245:125586. [PMID: 31881386 DOI: 10.1016/j.chemosphere.2019.125586] [Citation(s) in RCA: 179] [Impact Index Per Article: 44.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Revised: 11/28/2019] [Accepted: 12/08/2019] [Indexed: 05/25/2023]
Abstract
Minamata disease in Japan and the large-scale poisoning by methylmercury (MeHg) in Iraq caused wide public concerns about the risk emanating from mercury for human health. Nowadays, it is widely known that all forms of mercury induce toxic effects in mammals, and increasing evidence supports the concern that environmentally relevant levels of MeHg could impact normal biological functions in wildlife. The information of mechanism involved in mercurial toxicity is growing but knowledge gaps still exist between the adverse effects and mechanisms of action, especially at the molecular level. A body of data obtained from experimental studies on mechanisms of mercurial toxicity in vivo and in vitro points to that disruption of the antioxidant system may play an important role in the mercurial toxic effects. Moreover, the accumulating evidence indicates that signaling transduction, protein or/and enzyme activity, and gene regulation are involving in mediating toxic and adaptive response to mercury exposure. We conducted here a comprehensive review of mercurial toxic effects on wildlife and human, in particular synthesized key findings of molecular pathways involved in mercurial toxicity from the cells to human. We discuss the molecular evidence related mercurial toxicity to the adverse effects, with particular emphasis on the gene regulation. The further studies relying on Omic analysis connected to adverse effects and modes of action of mercury will aid in the evaluation and validation of causative relationship between health outcomes and gene expression.
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Affiliation(s)
- Lixin Yang
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, 100012, Beijing, China; Center for Global Health, School of Public Health, Nanjing Medical University, 211166, Nanjing, China.
| | - Yuanyuan Zhang
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, 100012, Beijing, China
| | - Feifei Wang
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, 100012, Beijing, China
| | - Zidie Luo
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, 100012, Beijing, China
| | - Shaojuan Guo
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, 100012, Beijing, China
| | - Uwe Strähle
- Toxicology and Genetics, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344, Eggenstein-Leopoldshafen, Germany
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13
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Lee SJ, Bae JH, Lee H, Lee H, Park J, Kang JS, Bae GU. Ginsenoside Rg3 upregulates myotube formation and mitochondrial function, thereby protecting myotube atrophy induced by tumor necrosis factor-alpha. JOURNAL OF ETHNOPHARMACOLOGY 2019; 242:112054. [PMID: 31271820 DOI: 10.1016/j.jep.2019.112054] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 06/26/2019] [Accepted: 06/30/2019] [Indexed: 06/09/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Ginsenoside Rg3 from Panax ginseng has reported to have multiple pharmacological activities including anti-diabetics, anti-inflammation and anti-cancer. However, the effect of ginsenoside Rg3 on myogenic differentiation and muscle atrophy is unknown. AIM TO THE STUDY In this study, we investigated the myogenic effect and underlying molecular mechanisms of ginsenoside Rg3 on myotube atrophy induced by tumor necrosis factor-α (TNF-α). MATERIALS AND METHODS C2C12 myoblasts were induced to differentiate for one day followed by the treatment of TNF-α along with vehicle or ginsenoside Rg3 for additional 2 days and subjected to immunoblotting, immunocytochemistry, quantitative RT-PCR and biochemical analysis for mitochondrial function. RESULTS Ginsenoside Rg3 promotes myogenic differentiation and multinucleated myotube formation through Akt activation in a dose-dependent manner, without any cytotoxicity. Ginsenoside Rg3 treatment restores myotube formation and increases myotube diameters under TNF-α-treated conditions. Ginsenoside Rg3 enhances Akt/mTOR (mammalian target of rapamycin) signaling that in turn stimulates muscle-specific gene expression such as myosin heavy chain (MHC) and Myogenin, and suppresses the expression of muscle-specific ubiquitin ligases. In addition, ginsenoside Rg3 in TNF-α-treated myotubes significantly inhibits the production of mitochondrial ROS and restores mitochondrial membrane potential (MMP) and ATP contents. Furthermore, ginsenoside Rg3 upregulates the activities and expression of peroxisome proliferator-activated receptor-γ coactivator-1α (PGC1α) and the mitochondrial biogenetic transcription factors, nuclear respiratory factor-1 (NRF1) and mitochondrial transcription factor A (Tfam) in TNF-α-induced myotube atrophy. CONCLUSIONS This study provides a mechanistic insight into the effect of ginsenoside Rg3 on myogenic differentiation and myotube atrophy, suggesting that ginsenoside Rg3 has a promising potential as a therapeutic or neutraceutical remedy to intervene muscle weakness and atrophy.
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Affiliation(s)
- Sang-Jin Lee
- Research Institute of Pharmaceutical Science, College of Pharmacy, Sookmyung Women's University, Seoul, 04310, Republic of Korea.
| | - Ju Hyun Bae
- Molecular Cell Biology, Single Cell Network Research Center, Sungkyunkwan University School of Medicine, Suwon, 16419, Republic of Korea.
| | - Hani Lee
- Research Institute of Pharmaceutical Science, College of Pharmacy, Sookmyung Women's University, Seoul, 04310, Republic of Korea.
| | - Hyunji Lee
- Department of Pharmacology, Metabolic Syndrome and Cell Signaling Laboratory, Institute for Cancer Research, College of Medicine, Chungnam National University, Daejeon, 35015, Republic of Korea.
| | - Jongsun Park
- Department of Pharmacology, Metabolic Syndrome and Cell Signaling Laboratory, Institute for Cancer Research, College of Medicine, Chungnam National University, Daejeon, 35015, Republic of Korea.
| | - Jong-Sun Kang
- Molecular Cell Biology, Single Cell Network Research Center, Sungkyunkwan University School of Medicine, Suwon, 16419, Republic of Korea.
| | - Gyu-Un Bae
- Research Institute of Pharmaceutical Science, College of Pharmacy, Sookmyung Women's University, Seoul, 04310, Republic of Korea.
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Usuki F, Yamashita A, Fujimura M. Environmental stresses suppress nonsense-mediated mRNA decay (NMD) and affect cells by stabilizing NMD-targeted gene expression. Sci Rep 2019; 9:1279. [PMID: 30718659 PMCID: PMC6362056 DOI: 10.1038/s41598-018-38015-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Accepted: 12/05/2018] [Indexed: 12/31/2022] Open
Abstract
Nonsense-mediated mRNA decay (NMD) is a cellular mechanism that eliminates mRNAs that harbor premature translation termination codons (PTCs). Here, we investigated the effects of environmental stresses (oxidative stress and endoplasmic reticulum (ER) stress) on NMD activity. Methylmercury (MeHg) was used to cause oxidative stress and thapsigargin to stress the ER. NMD suppression, evidenced by upregulation of NMD-sensitive mRNAs and a decrease in UPF1 phosphorylation, was observed in MeHg-treated myogenic cells, cerebral cortical neuronal cells, and astroglial cells. Mild ER stress amplified NMD suppression caused by MeHg. To elucidate the cause of stress-induced NMD suppression, the role of the phospho-eIF2α/ATF4 pathway was investigated. Knockdown and non-phosphorylatable eIF2α-transfection studies demonstrated the critical role of phospho-eIF2α-mediated repression of translation in mild ER stress-induced NMD suppression. However, NMD suppression was also observed in phospho-eIF2α-deficient cells under mild ER stress. Mechanistic target of rapamycin suppression-induced inhibition of cap-dependent translation, and downregulation of the NMD components UPF1, SMG7, and eIF4A3, were probably involved in stress-induced NMD suppression. Our results indicate that stress-induced NMD suppression has the potential to affect the condition of cells and phenotypes of PTC-related diseases under environmental stresses by stabilizing NMD-targeted gene expression.
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Affiliation(s)
- Fusako Usuki
- Department of Clinical Medicine, National Institute for Minamata Disease, 4058-18 Hama, Minamata, 867-0008, Japan.
| | - Akio Yamashita
- Department of Molecular Biology, Yokohama City University School of Medicine, 3-9 Fuku-ura, Kanazawa, Yokohama, 236-0004, Japan
| | - Masatake Fujimura
- Basic Medical Sciences, National Institute for Minamata Disease, 4058-18 Hama, Minamata, 867-0008, Japan
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15
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Cariccio VL, Samà A, Bramanti P, Mazzon E. Mercury Involvement in Neuronal Damage and in Neurodegenerative Diseases. Biol Trace Elem Res 2019; 187:341-356. [PMID: 29777524 DOI: 10.1007/s12011-018-1380-4] [Citation(s) in RCA: 86] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Accepted: 05/07/2018] [Indexed: 12/11/2022]
Abstract
Neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, and multiple sclerosis are characterized by a chronic and selective process of neuronal cell death. Although the causes of neurodegenerative diseases remain still unknown, it is now a well-established idea that more factors, such as genetic, endogenous, and environmental, are involved. Among environmental causes, the accumulation of mercury, a heavy metal considered a toxic agent, was largely studied as a probable factor involved in neurodegenerative disease course. Mercury exists in three main forms: elemental mercury, inorganic mercury, and organic mercury (methylmercury and ethylmercury). Sources of elemental mercury can be natural (volcanic emission) or anthropogenic (coal-fired electric utilities, waste combustion, hazardous-waste incinerators, and gold extraction). Moreover, mercury is still used as an antiseptic, as a medical preservative, and as a fungicide. Dental amalgam can emit mercury vapor. Mercury vapor, being highly volatile and lipid soluble, can cross the blood-brain barrier and the lipid cell membranes and can be accumulated into the cells in its inorganic forms. Also, methylmercury can pass through blood-brain and placental barriers, causing serious damage in the central nervous system. This review describes the toxic effects of mercury in cell cultures, in animal models, and in patients with neurodegenerative diseases. In vitro experiments showed that mercury exposure was principally involved in oxidative stress and apoptotic processes. Moreover, motor and cognitive impairment and neural loss have been confirmed in various studies performed in animal models. Finally, observational studies on patients with neurodegenerative diseases showed discordant data about a possible mercury involvement.
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Affiliation(s)
- Veronica Lanza Cariccio
- IRCCS Centro Neurolesi "Bonino Pulejo", Via Provinciale Palermo, Contrada Casazza, 98124, Messina, Italy
| | - Annalisa Samà
- IRCCS Centro Neurolesi "Bonino Pulejo", Via Provinciale Palermo, Contrada Casazza, 98124, Messina, Italy
| | - Placido Bramanti
- IRCCS Centro Neurolesi "Bonino Pulejo", Via Provinciale Palermo, Contrada Casazza, 98124, Messina, Italy
| | - Emanuela Mazzon
- IRCCS Centro Neurolesi "Bonino Pulejo", Via Provinciale Palermo, Contrada Casazza, 98124, Messina, Italy.
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16
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Bjørklund G, Skalny AV, Rahman MM, Dadar M, Yassa HA, Aaseth J, Chirumbolo S, Skalnaya MG, Tinkov AA. Toxic metal(loid)-based pollutants and their possible role in autism spectrum disorder. ENVIRONMENTAL RESEARCH 2018; 166:234-250. [PMID: 29902778 DOI: 10.1016/j.envres.2018.05.020] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Revised: 05/18/2018] [Accepted: 05/18/2018] [Indexed: 06/08/2023]
Abstract
Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by deficits in social interaction, verbal and non-verbal communication, and stereotypic behaviors. Many studies support a significant relationship between many different environmental factors in ASD etiology. These factors include increased daily exposure to various toxic metal-based environmental pollutants, which represent a cause for concern in public health. This article reviews the most relevant toxic metals, commonly found, environmental pollutants, i.e., lead (Pb), mercury (Hg), aluminum (Al), and the metalloid arsenic (As). Additionally, it discusses how pollutants can be a possible pathogenetic cause of ASD through various mechanisms including neuroinflammation in different regions of the brain, fundamentally occurring through elevation of the proinflammatory profile of cytokines and aberrant expression of nuclear factor kappa B (NF-κB). Due to the worldwide increase in toxic environmental pollution, studies on the role of pollutants in neurodevelopmental disorders, including direct effects on the developing brain and the subjects' genetic susceptibility and polymorphism, are of utmost importance to achieve the best therapeutic approach and preventive strategies.
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Affiliation(s)
- Geir Bjørklund
- Council for Nutritional and Environmental Medicine, Mo i Rana, Norway.
| | - Anatoly V Skalny
- Peoples' Friendship University of Russia (RUDN University), Moscow, Russia; Yaroslavl State University, Yaroslavl, Russia; All-Russian Research Institute of Medicinal and Aromatic Plants, Moscow, Russia
| | - Md Mostafizur Rahman
- Department of Environmental Sciences, Jahangirnagar University, Dhaka, Bangladesh; Graduate School of Environmental Science, Hokkaido University, Japan
| | - Maryam Dadar
- Razi Vaccine and Serum Research Institute, Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran
| | - Heba A Yassa
- Faculty of Medicine, Assiut University, Assiut, Egypt
| | - Jan Aaseth
- Faculty of Health and Social Sciences, Inland Norway University of Applied Sciences, Elverum, Norway; Department of Research, Innlandet Hospital Trust, Brumunddal, Norway
| | - Salvatore Chirumbolo
- Department of Neurological and Movement Sciences, University of Verona, Verona, Italy
| | | | - Alexey A Tinkov
- Peoples' Friendship University of Russia (RUDN University), Moscow, Russia; Yaroslavl State University, Yaroslavl, Russia
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17
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Karri V, Ramos D, Martinez JB, Odena A, Oliveira E, Coort SL, Evelo CT, Mariman ECM, Schuhmacher M, Kumar V. Differential protein expression of hippocampal cells associated with heavy metals (Pb, As, and MeHg) neurotoxicity: Deepening into the molecular mechanism of neurodegenerative diseases. J Proteomics 2018; 187:106-125. [PMID: 30017948 DOI: 10.1016/j.jprot.2018.06.020] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Revised: 06/26/2018] [Accepted: 06/26/2018] [Indexed: 12/29/2022]
Abstract
Chronic exposure to heavy metals such as Pb, As, and MeHg can be associated with an increased risk of developing neurodegenerative diseases. Our in vitro bioassays results showed the potency of heavy metals in the order of Pb < As < MeHg on hippocampal cells. The main objective of this study was combining in vitro label free proteomics and systems biology approach for elucidating patterns of biological response, discovering underlying mechanisms of Pb, As, and MeHg toxicity in hippocampal cells. The omics data was refined by using different filters and normalization and multilevel analysis tools were employed to explore the data visualization. The functional and pathway visualization was performed by using Gene ontology and PathVisio tools. Using these all integrated approaches, we identified significant proteins across treatments within the mitochondrial dysfunction, oxidative stress, ubiquitin proteome dysfunction, and mRNA splicing related to neurodegenerative diseases. The systems biology analysis revealed significant alterations in proteins implicated in Parkinson's disease (PD) and Alzheimer's disease (AD). The current proteomics analysis of three metals support the insight into the proteins involved in neurodegeneration and the altered proteins can be useful for metal-specific biomarkers of exposure and its adverse effects. SIGNIFICANCE The proteomics techniques have been claimed to be more sensitive than the conventional toxicological assays, facilitating the measurement of responses to heavy metals (Pb, As, and MeHg) exposure before obvious harm has occurred demonstrating their predictive value. Also, proteomics allows for the comparison of responses between Pb, As, and MeHg metals, permitting the evaluation of potency differences hippocampal cells of the brain. Hereby, the molecular information provided by pathway and gene functional analysis can be used to develop a more thorough understanding of each metal mechanism at the protein level for different neurological adverse outcomes (e.g. Parkinson's disease, Alzheimer's diseases). Efforts are put into developing proteomics based toxicity testing methods using in vitro models for improving human risk assessment. Some of the key proteins identified can also potentially be used as biomarkers in epidemiologic studies. These heavy metal response patterns shed new light on the mechanisms of mRNA splicing, ubiquitin pathway role in neurodegeneration, and can be useful for the development of molecular biomarkers of heavy metals exposure.
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Affiliation(s)
- Venkatanaidu Karri
- Environmental Engineering Laboratory, Departament d'Enginyeria Quimica, Universitat Rovira i Virgili, Av. Països Catalans 26, 43007 Tarragona, Spain
| | - David Ramos
- Plataforma de Proteòmica, Parc Científic de Barcelona, C/Baldiri Reixac, 10-12, 08028 Barcelona, Spain
| | - Julia Bauzá Martinez
- Plataforma de Proteòmica, Parc Científic de Barcelona, C/Baldiri Reixac, 10-12, 08028 Barcelona, Spain
| | - Antonia Odena
- Plataforma de Proteòmica, Parc Científic de Barcelona, C/Baldiri Reixac, 10-12, 08028 Barcelona, Spain
| | - Eliandre Oliveira
- Unidad de Toxicologia, Parc Científic de Barcelona, C/Baldiri Reixac, 10-12, 08028 Barcelona, Spain
| | - Susan L Coort
- Department of Bioinformatics, BiGCaT, NUTRIM, Maastricht University, 6229, ER, Maastricht, the Netherlands
| | - Chris T Evelo
- Department of Bioinformatics, BiGCaT, NUTRIM, Maastricht University, 6229, ER, Maastricht, the Netherlands
| | - Edwin C M Mariman
- Department of Human Biology, NUTRIM School for Nutrition, Toxicology and Metabolism, Maastricht University Medical Centre, Maastricht, the Netherlands
| | - Marta Schuhmacher
- Environmental Engineering Laboratory, Departament d'Enginyeria Quimica, Universitat Rovira i Virgili, Av. Països Catalans 26, 43007 Tarragona, Spain
| | - Vikas Kumar
- Environmental Engineering Laboratory, Departament d'Enginyeria Quimica, Universitat Rovira i Virgili, Av. Països Catalans 26, 43007 Tarragona, Spain; IISPV, Hospital Universitari Sant Joan de Reus, Universitat Rovira I Virgili, Reus, Spain.
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18
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Sakamoto M, Chan HM, Domingo JL, Koriyama C, Murata K. Placental transfer and levels of mercury, selenium, vitamin E, and docosahexaenoic acid in maternal and umbilical cord blood. ENVIRONMENT INTERNATIONAL 2018; 111:309-315. [PMID: 29150340 DOI: 10.1016/j.envint.2017.11.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Revised: 10/27/2017] [Accepted: 11/02/2017] [Indexed: 06/07/2023]
Abstract
Methylmercury (MeHg) is a neurotoxicant known to affect the developing fetal brain as a sensitive target organ. As most mercury (Hg) in blood is MeHg, total mercury (THg) levels in blood are used to estimate the body burden of MeHg. The nutrients selenium (Se), vitamin E, and docosahexaenoic acid (DHA) are protective against MeHg toxicity. We compared maternal and cord blood concentrations of biochemical substances, THg and Se, vitamin E, DHA, and other elements, fatty acids, and amino acids in 54 Japanese mother-newborn pairs to elucidate the fetal risk of MeHg toxicity. Cord blood had higher hematocrit and amino acid values and lower concentrations of lipid components, including fatty acids compared with maternal blood. THg levels in cord blood (7.26ng/g) were 1.9 times higher than levels in maternal blood (3.79ng/g). Se concentrations in cord blood (176ng/g) were slightly higher than concentrations in maternal blood (156ng/g). Levels of vitamin E (0.31mg/dL) and DHA (58.8μg/mL) in cord blood were much lower than levels in maternal blood (1.38mg/dL and 147μg/mL, respectively). The ratios of Se/THg, vitamin E/THg, and DHA/THg in cord blood were lower than ratios in maternal blood. These results suggest that fetuses are at higher risk to MeHg toxicity.
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Affiliation(s)
- Mineshi Sakamoto
- Environmental Health Section, Department of Environmental Science and Epidemiology, National Institute for Minamata Disease, Minamata, Japan; Department of Epidemiology and Preventive Medicine, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan.
| | - Hing Man Chan
- Department of Biology, University of Ottawa, Ottawa, ON, Canada
| | - José L Domingo
- Laboratory of Toxicology and Environmental Health, School of Medicine, IISPV, Universitat "Rovira i Virgili", Reus, Spain
| | - Chihaya Koriyama
- Department of Epidemiology and Preventive Medicine, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Katsuyuki Murata
- Department of Environmental Health Sciences, Akita University Graduate School of Medicine, Akita, Japan
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19
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Banerjee M, Roy G. Cleavage of Hg–C Bonds of Organomercurials Induced by ImOHSe via Two Distinct Pathways. Inorg Chem 2017; 56:12739-12750. [DOI: 10.1021/acs.inorgchem.7b01301] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Mainak Banerjee
- Department of Chemistry, School of Natural
Sciences, Shiv Nadar University, NH91, Dadri, Gautam Buddha Nagar, Uttar Pradesh 201314, India
| | - Gouriprasanna Roy
- Department of Chemistry, School of Natural
Sciences, Shiv Nadar University, NH91, Dadri, Gautam Buddha Nagar, Uttar Pradesh 201314, India
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20
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The Putative Role of Environmental Mercury in the Pathogenesis and Pathophysiology of Autism Spectrum Disorders and Subtypes. Mol Neurobiol 2017; 55:4834-4856. [DOI: 10.1007/s12035-017-0692-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2017] [Accepted: 07/13/2017] [Indexed: 01/28/2023]
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21
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Culbreth M, Zhang Z, Aschner M. Methylmercury augments Nrf2 activity by downregulation of the Src family kinase Fyn. Neurotoxicology 2017; 62:200-206. [PMID: 28736149 DOI: 10.1016/j.neuro.2017.07.028] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Revised: 07/17/2017] [Accepted: 07/17/2017] [Indexed: 12/26/2022]
Abstract
Methylmercury (MeHg) is a potent developmental neurotoxicant that induces an oxidative stress response in the brain. It has been demonstrated that MeHg exposure increases nuclear factor erythroid 2-related factor 2 (Nrf2) activity. Nrf2 is a transcription factor that translocates to the nucleus in response to oxidative stress, and upregulates phase II detoxifying enzymes. Although, Nrf2 activity is augmented subsequent to MeHg exposure, it has yet to be established whether Nrf2 moves into the nucleus as a result. Furthermore, the potential effect MeHg might have on the non-receptor tyrosine kinase, Fyn, has not been addressed. Fyn phosphorylates Nrf2 in the nucleus, resulting in its inactivation, and consequent downregulation of the oxidative stress response. Here, we observe Nrf2 translocates to the nucleus subsequent to MeHg-induced oxidative stress. This response is concomitant with reduced Fyn expression and nuclear localization. Moreover, we detected an increase in phosphorylated Akt and glycogen synthase kinase 3 beta (GSK-3β) at activating and inhibitory sites, respectively. Akt phosphorylates and inhibits GSK-3β, which subsequently prevents Fyn phosphorylation to signal nuclear import. Our results demonstrate MeHg downregulates Fyn to maintain Nrf2 activity, and further illuminate a potential mechanism by which MeHg elicits neurotoxicity.
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Affiliation(s)
- Megan Culbreth
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, United States.
| | - Ziyan Zhang
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, United States
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, United States
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22
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Lee HI, Park BR, Chun SW. Reactive oxygen species increase neuronal excitability via activation of nonspecific cation channel in rat medullary dorsal horn neurons. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2017; 21:371-376. [PMID: 28706450 PMCID: PMC5507775 DOI: 10.4196/kjpp.2017.21.4.371] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/27/2016] [Revised: 03/10/2017] [Accepted: 03/20/2017] [Indexed: 02/07/2023]
Abstract
The caudal subnucleus of the spinal trigeminal nucleus (medullary dorsal horn; MDH) receives direct inputs from small diameter primary afferent fibers that predominantly transmit nociceptive information in the orofacial region. Recent studies indicate that reactive oxygen species (ROS) is involved in persistent pain, primarily through spinal mechanisms. In this study, we aimed to investigate the role of xanthine/xanthine oxidase (X/XO) system, a known generator of superoxide anion (O2·−), on membrane excitability in the rat MDH neurons. For this, we used patch clamp recording and confocal imaging. An application of X/XO (300 µM/30 mU) induced membrane depolarization and inward currents. When slices were pretreated with ROS scavengers, such as phenyl N-tert-butylnitrone (PBN), superoxide dismutase (SOD), and catalase, X/XO-induced responses decreased. Fluorescence intensity in the DCF-DA and DHE-loaded MDH cells increased on the application of X/XO. An anion channel blocker, 4,4-diisothiocyanatostilbene-2,2-disulfonic acid (DIDS), significantly decreased X/XO-induced depolarization. X/XO elicited an inward current associated with a linear current-voltage relationship that reversed near −40 mV. X/XO-induced depolarization reduced in the presence of La3+, a nonselective cation channel (NSCC) blocker, and by lowering the external sodium concentration, indicating that membrane depolarization and inward current are induced by influx of Na+ ions. In conclusion, X/XO-induced ROS modulate the membrane excitability of MDH neurons, which was related to the activation of NSCC.
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Affiliation(s)
- Hae In Lee
- Department of Dental Hygiene, Gwangyang Health Science University, Gwangyang 57764, Korea
| | - Byung Rim Park
- Department of Physiology, College of Medicine, Wonkwang University, Iksan 54538, Korea
| | - Sang Woo Chun
- Department of Oral Physiology, College of Dentistry, Wonkwang University, Iksan 54538, Korea
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23
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Banerjee M, Karri R, Chalana A, Das R, Rai RK, Rawat KS, Pathak B, Roy G. Protection of Endogenous Thiols against Methylmercury with Benzimidazole-Based Thione by Unusual Ligand-Exchange Reactions. Chemistry 2017; 23:5696-5707. [DOI: 10.1002/chem.201605238] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Indexed: 12/27/2022]
Affiliation(s)
- Mainak Banerjee
- Department of Chemistry; School of Natural Sciences; Shiv Nadar University, NH91, Dadri; Gautam Buddha Nagar, UP 201314 India
| | - Ramesh Karri
- Department of Chemistry; School of Natural Sciences; Shiv Nadar University, NH91, Dadri; Gautam Buddha Nagar, UP 201314 India
| | - Ashish Chalana
- Department of Chemistry; School of Natural Sciences; Shiv Nadar University, NH91, Dadri; Gautam Buddha Nagar, UP 201314 India
| | - Ranajit Das
- Department of Chemistry; School of Natural Sciences; Shiv Nadar University, NH91, Dadri; Gautam Buddha Nagar, UP 201314 India
| | - Rakesh Kumar Rai
- Department of Chemistry; School of Natural Sciences; Shiv Nadar University, NH91, Dadri; Gautam Buddha Nagar, UP 201314 India
| | - Kuber Singh Rawat
- Discipline of Chemistry and Discipline of Metallurgy Engineering and Materials Science; Indian Institute of Technology (IIT) Indore; Indore, MP 453552 India
| | - Biswarup Pathak
- Discipline of Chemistry and Discipline of Metallurgy Engineering and Materials Science; Indian Institute of Technology (IIT) Indore; Indore, MP 453552 India
| | - Gouriprasanna Roy
- Department of Chemistry; School of Natural Sciences; Shiv Nadar University, NH91, Dadri; Gautam Buddha Nagar, UP 201314 India
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Ghizoni H, de Souza V, Straliotto MR, de Bem AF, Farina M, Hort MA. Superoxide anion generation and oxidative stress in methylmercury-induced endothelial toxicity in vitro. Toxicol In Vitro 2017; 38:19-26. [DOI: 10.1016/j.tiv.2016.10.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Revised: 10/12/2016] [Accepted: 10/26/2016] [Indexed: 12/23/2022]
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Maternal methylmercury from a wild-caught walleye diet induces developmental abnormalities in zebrafish. Reprod Toxicol 2016; 65:272-282. [DOI: 10.1016/j.reprotox.2016.08.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Revised: 08/03/2016] [Accepted: 08/16/2016] [Indexed: 01/20/2023]
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Seo JS, Yoo DY, Jung HY, Kim DW, Hwang IK, Lee JY, Moon SM. Effects of Dendropanax morbifera Léveille extracts on cadmium and mercury secretion as well as oxidative capacity: A randomized, double-blind, placebo-controlled trial. Biomed Rep 2016; 4:623-627. [PMID: 27123258 DOI: 10.3892/br.2016.623] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Accepted: 02/22/2016] [Indexed: 01/23/2023] Open
Abstract
In this randomized, double-blind, placebo controlled clinical trial, the effects of Dendropanax morbifera (D. morbifera) Léveille on heavy metal (cadmium and mercury) excretion as well as on lipid peroxidation and Cu, Zn-superoxide dismutase (SOD1) activity were investigated. For this study, tablets containing placebo or 300 mg of the leaf extract from D. morbifera Léveille were used. A total of 60 eligible healthy subjects were enrolled in this randomized, double-blind, placebo-controlled study. The differences in cadmium, mercury, and malondialdehyde (MDA) levels and SOD1 activity were measured in the serum 60 days after treatment with placebo or D. morbifera Léveille extracts. No significant differences between baseline characteristics and biochemical values were identified in subjects in the placebo and D. morbifera Léveille groups. Serum levels of cadmium, mercury and MDA decreased following consumption of D. morbifera Léveille extracts; however, no significant differences were identified. In addition, female, but not male, subjects who consumed D. morbifera Léveille extracts showed a significant increase in SOD1 activity. This result suggests that chronic consumption of D. morbifera Léveille extract can help to facilitate excretion of cadmium and mercury from serum and increase the antioxidant capacity in humans.
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Affiliation(s)
- Jae Sam Seo
- Department of Neurosurgery, Dongtan Sacred Heart Hospital, College of Medicine, Hallym University, Hwaseong 445-170, Republic of Korea
| | - Dae Young Yoo
- Department of Anatomy and Cell Biology, College of Veterinary Medicine, and Research Institute for Veterinary Science, Seoul National University, Seoul 151-742, Republic of Korea
| | - Hyo Young Jung
- Department of Anatomy and Cell Biology, College of Veterinary Medicine, and Research Institute for Veterinary Science, Seoul National University, Seoul 151-742, Republic of Korea
| | - Dong-Woo Kim
- Central Research Center, Egreen Co., Ltd., Seongnam 463-862, Republic of Korea
| | - In Koo Hwang
- Department of Anatomy and Cell Biology, College of Veterinary Medicine, and Research Institute for Veterinary Science, Seoul National University, Seoul 151-742, Republic of Korea
| | - Jong Young Lee
- Department of Neurosurgery, Kangdong Sacred Heart Hospital, College of Medicine, Hallym University, Seoul 134-701, Republic of Korea
| | - Seung Myung Moon
- Department of Neurosurgery, Dongtan Sacred Heart Hospital, College of Medicine, Hallym University, Hwaseong 445-170, Republic of Korea
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Caito SW, Aschner M. NAD+ Supplementation Attenuates Methylmercury Dopaminergic and Mitochondrial Toxicity in Caenorhabditis Elegans. Toxicol Sci 2016; 151:139-49. [PMID: 26865665 DOI: 10.1093/toxsci/kfw030] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Methylmercury (MeHg) is a neurotoxic contaminant of our fish supply that has been linked to dopaminergic (DAergic) dysfunction that characterizes Parkinson's disease. We have previously shown that MeHg causes both morphological and behavioral changes in the Caenorhabditis elegans DAergic neurons that are associated with oxidative stress. We were therefore interested in whether the redox sensitive cofactor nicotinamide adenine dinucleotide (NAD(+)) may be affected by MeHg and whether supplementation of NAD( + )may prevent MeHg-induced toxicities. Worms treated with MeHg showed depletion in cellular NAD( + )levels, which was prevented by NAD( + )supplementation prior to MeHg treatment. NAD( + )supplementation also prevented DAergic neurodegeneration and deficits in DAergic-dependent behavior upon MeHg exposure. In a mutant worm line that cannot synthesize NAD( + )from nicotinamide, MeHg lethality and DAergic behavioral deficits were more sensitive to MeHg than wildtype worms, demonstrating the importance of NAD( + )in MeHg toxicity. In wildtype worms, NAD( + )supplementation provided protection from MeHg-induced oxidative stress and mitochondrial dysfunction. These data show the importance of NAD( + )levels in the response to MeHg exposure. NAD( + )supplementation may be beneficial for MeHg-induced toxicities and preventing cellular damage involved in Parkinson's disease.
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Affiliation(s)
- Samuel W Caito
- 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
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Dysregulation of Glutamate Cycling Mediates Methylmercury-Induced Neurotoxicity. ADVANCES IN NEUROBIOLOGY 2016; 13:295-305. [PMID: 27885634 DOI: 10.1007/978-3-319-45096-4_11] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
To examine the toxicological implications of glutamate, this chapter will focus specifically on its impact in the brain. More explicitly, it will illustrate the role glutamate plays in mediating methylmercury (MeHg)-induced neurotoxicity. In this chapter, one intends to highlight the processes that occur prior to glutamate-stimulated excitotoxicity and subsequent neurodegeneration. As such, it will emphasize three main routes by which MeHg alters glutamate homeostasis. It is essential to recognize that these effects are not mutually exclusive, and that they synergistically influence glutamate dysregulation. Furthermore, the consequences of MeHg exposure will be presented here as a direct pathway; however, it must be noted these effects occur simultaneously. First, glutamate uptake will be reviewed emphasizing the function of astrocytes. Next, the induction of oxidative stress by MeHg exposure will be discussed. This process has a two-fold effect on glutamate homeostasis by (1) inhibiting extracellular glutamate uptake and (2) altering transcription of genes vital to glutamate cycling. Finally, the impact glutamate dysregulation has on glutathione synthesis will be examined. Although this chapter centers on the link between glutamate and MeHg toxicity, it is imperative that the reader acknowledges the processes discussed here can be extended to any pro-oxidant.
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Kim W, Kim DW, Yoo DY, Jung HY, Kim JW, Kim DW, Choi JH, Moon SM, Yoon YS, Hwang IK. Antioxidant effects of Dendropanax morbifera Léveille extract in the hippocampus of mercury-exposed rats. Altern Ther Health Med 2015. [PMID: 26201852 PMCID: PMC4511420 DOI: 10.1186/s12906-015-0786-1] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Background Dendropanax morbifera Léveille has been employed for the treatment of infectious diseases using folk medicine. In this study, we evaluated the antioxidant effects of a leaf extract of Dendropanax morbifera Léveille in the hippocampus of mercury-exposed rats. Methods Seven-week-old Sprague–Dawley rats received a daily intraperitoneal injection of 5 μg/kg dimethylmercury and/or oral Dendropanax morbifera Léveille leaf extract (100 mg/kg) for 4 weeks. Animals were sacrificed 2 h after the last dimethylmercury and/or leaf extract treatment. Mercury levels were measured in homogenates of hippocampal tissue, a brain region that is vulnerable to mercury toxicity. In addition, we measured reactive oxygen species production, lipid peroxidation levels, and antioxidant levels in these hippocampal homogenates. Results Treatment with Dendropanax morbifera Léveille leaf extract significantly reduced mercury levels in hippocampal homogenates and attenuated the dimethylmercury-induced increase in the production of reactive oxygen species and formation of malondialdehyde. In addition, this leaf extract treatment significantly reversed the dimethylmercury-induced reduction in the hippocampal activities of Cu, Zn-superoxide dismutase, catalase, glutathione peroxidase, and glutathione-S-transferase. Conclusion These results suggest that a leaf extract of Dendropanax morbifera Léveille had strong antioxidant effects in the hippocampus of mercury-exposed rats.
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Muniroh M, Khan N, Koriyama C, Akiba S, Vogel CFA, Yamamoto M. Suppression of methylmercury-induced IL-6 and MCP-1 expressions by N-acetylcysteine in U-87MG human astrocytoma cells. Life Sci 2015; 134:16-21. [PMID: 26006043 DOI: 10.1016/j.lfs.2015.04.024] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2015] [Revised: 04/09/2015] [Accepted: 04/23/2015] [Indexed: 10/23/2022]
Abstract
AIMS The aim of this study was to clarify the involvement of oxidative stress in methylmercury (MeHg)-induced pro-inflammatory cytokine expressions and the suppressive effects of N-acetylcysteine (NAC) in MeHg-induced cytokine expression. MATERIALS AND METHODS Using U-87-MG human astrocytoma cell line, interleukin (IL)-6 and monocyte chemoattractant protein (MCP)-1 expressions induced by 4 μM MeHg were measured at mRNA and protein levels. Hydrogen peroxide (H2O2) and superoxide anion (O2(-)) were quantified by flow-cytometry analysis. To examine the suppressive effects of NAC on the cytokine expressions among different timing of NAC treatment, cells were treated with 0.5 or 5mM NAC before, simultaneously, or after MeHg administration. KEY FINDINGS MeHg exposure at 4 μM, a non-cytotoxic concentration, significantly induced MCP-1 and IL-6 expressions at both mRNA and protein levels. A significant increase of H2O2 production but not O2(-) was observed. MeHg-induced expression of MCP-1 and IL-6 mRNA was reduced by 10-20% in the presence of 5mM NAC (co-treatment experiment) compared to cells treated with MeHg only. Pre-treatment of cells with 0.5 or 5mM NAC at 0.5 or 1h and its subsequent washout before MeHg addition suppressed MCP-1 and IL-6 cytokine expressions. Post-treatment of cells with NAC after MeHg addition also suppressed the cytokine induction, but the magnitude of suppression was evidently lower than in co-treated cells even though the H2O2 generation was almost completely suppressed by NAC. SIGNIFICANCE NAC may effectively suppress the MeHg-induced cytokine production through both, inhibition of reactive oxygen species as well as extracellular chelation of MeHg in astrocytes.
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Affiliation(s)
- Muflihatul Muniroh
- Department of Epidemiology and Preventive Medicine, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima 890-8520, Japan; Department of Physiology, Faculty of Medicine, Diponegoro University, Tembalang, Semarang 50725, Indonesia
| | - Noureen Khan
- Department of Epidemiology and Preventive Medicine, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima 890-8520, Japan
| | - Chihaya Koriyama
- Department of Epidemiology and Preventive Medicine, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima 890-8520, Japan.
| | - Suminori Akiba
- Department of Epidemiology and Preventive Medicine, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima 890-8520, Japan
| | - Christoph F A Vogel
- Department of Environmental Toxicology and Center for Health and the Environment, University of California, Davis, CA 95616, USA
| | - Megumi Yamamoto
- Integrated Physiology Section, Department of Basic Medical Science, National Institute for Minamata Disease, 4058-18 Hama, Minamata, Kumamoto 867-0008, Japan
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Truong J, Mailloux RJ, Chan HM. Impact of methylmercury exposure on mitochondrial energetics in AC16 and H9C2 cardiomyocytes. Toxicol In Vitro 2015; 29:953-61. [PMID: 25835517 DOI: 10.1016/j.tiv.2015.03.016] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2015] [Revised: 03/23/2015] [Accepted: 03/25/2015] [Indexed: 10/23/2022]
Abstract
It has been reported that chronic low dose exposures of methylmercury (MeHg) is associated with cardiovascular diseases in many populations worldwide. The toxic mechanisms through which these adverse effects occur are currently unknown. The objective of this study was to determine the bioenergetic and cytotoxic effects of MeHg on AC16 and H9C2 cardiomyocyte cell lines. Both cell lines exhibit significantly decreased mitochondrial function, cell viability and increased reactive oxygen species (ROS) production. Decreases in maximal respiration and reserve capacity was observed in both cell lines at 1μM. Bioenergetic profile experiments were also performed in tandem with cells exposed to diamide or menadione, compounds which accumulate in mitochondria and disrupt oxidative phosphorylation. AC16 cells show MeHg dose dependant sensitivities with Stateapparent and ATP production values, but H9C2 cells do not show these trends. H9C2 cells may be more resistant to MeHg toxicity than AC16 cells as reflected in the increases of proton leak and Stateapparent. No changes in expression of respiratory complexes were observed. Results suggest that MeHg has the potential to induce cytotoxicity. Furthermore, MeHg may have differential effects on AC16 and H9C2 cells, derived from human and rat cardiac tissue respectively, suggesting that differences in MeHg toxicity may be species-dependent.
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Affiliation(s)
- Jocelyn Truong
- Center for Advanced Research in Environmental Genomics, University of Ottawa, Ottawa, ON K1N 6N5, Canada
| | - Ryan J Mailloux
- Center for Advanced Research in Environmental Genomics, University of Ottawa, Ottawa, ON K1N 6N5, Canada
| | - Hing Man Chan
- Center for Advanced Research in Environmental Genomics, University of Ottawa, Ottawa, ON K1N 6N5, Canada.
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Tinkov AA, Ajsuvakova OP, Skalnaya MG, Popova EV, Sinitskii AI, Nemereshina ON, Gatiatulina ER, Nikonorov AA, Skalny AV. Mercury and metabolic syndrome: a review of experimental and clinical observations. Biometals 2015; 28:231-54. [DOI: 10.1007/s10534-015-9823-2] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Accepted: 01/15/2015] [Indexed: 12/16/2022]
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Makino K, Okuda K, Sugino E, Nishiya T, Toyama T, Iwawaki T, Fujimura M, Kumagai Y, Uehara T. Correlation Between Attenuation of Protein Disulfide Isomerase Activity Through S-Mercuration and Neurotoxicity Induced by Methylmercury. Neurotox Res 2014; 27:99-105. [DOI: 10.1007/s12640-014-9494-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Revised: 09/22/2014] [Accepted: 09/29/2014] [Indexed: 10/24/2022]
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Caito S, Zeng H, Aschner JL, Aschner M. Methylmercury alters the activities of Hsp90 client proteins, prostaglandin E synthase/p23 (PGES/23) and nNOS. PLoS One 2014; 9:e98161. [PMID: 24852575 PMCID: PMC4031136 DOI: 10.1371/journal.pone.0098161] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Accepted: 04/29/2014] [Indexed: 01/14/2023] Open
Abstract
Methylmercury (MeHg) is a persistent pollutant with known neurotoxic effects. We have previously shown that astrocytes accumulate MeHg and play a prominent role in mediating MeHg toxicity in the central nervous system (CNS) by altering glutamate signaling, generating oxidative stress, depleting glutathione (GSH) and initiating lipid peroxidation. Interestingly, all of these pathways can be regulated by the constitutively expressed, 90-kDa heat shock protein, Hsp90. As Hsp90 function is regulated by oxidative stress, we hypothesized that MeHg disrupts Hsp90-client protein functions. Astrocytes were treated with MeHg and expression of Hsp90, as well as the abundance of complexes of Hsp90-neuronal nitric oxide synthase (nNOS) and Hsp90-prostaglandin E synthase/p23 (PGES/p23) were assessed. MeHg exposure decreased Hsp90 protein expression following 12 h of treatment while shorter exposures had no effect on Hsp90 protein expression. Interestingly, following 1 or 6 h of MeHg exposure, Hsp90 binding to PGES/p23 or nNOS was significantly increased, resulting in increased prostaglandin E2 (PGE2) synthesis from MeHg-treated astrocytes. These effects were attenuated by the Hsp90 antagonist, geldanmycin. NOS activity was increased following MeHg treatment while cGMP formation was decreased. This was accompanied by an increase in •O2− and H2O2 levels, suggesting that MeHg uncouples NO formation from NO-dependent signaling and increases oxidative stress. Altogether, our data demonstrates that Hsp90 interactions with client proteins are increased following MeHg exposure, but over time Hsp90 levels decline, contributing to oxidative stress and MeHg-dependent excitotoxicity.
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Affiliation(s)
- Samuel Caito
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Heng Zeng
- Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
| | - Judy L Aschner
- Department of Pediatrics and Obstetrics & Gynecology and Women's Health, Albert Einstein College of Medicine of Yeshiva University and Children's Hospital at Montefiore, Bronx, New York, United States of America
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York, United States of America; Department of Pediatrics, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America; Department of Pediatrics and Obstetrics & Gynecology and Women's Health, Albert Einstein College of Medicine of Yeshiva University and Children's Hospital at Montefiore, Bronx, New York, United States of America; The Kennedy Center, Albert Einstein College of Medicine, Bronx, New York, United States of America
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Cowan EA, Taylor JL, Oldham CD, Dasari M, Doyle D, Murthy N, May SW. Cellular antioxidant activity of phenylaminoethyl selenides as monitored by chemiluminescence of peroxalate nanoparticles and by reduction of lipopolysaccharide-induced oxidative stress. Enzyme Microb Technol 2013; 53:373-7. [DOI: 10.1016/j.enzmictec.2013.08.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Accepted: 08/09/2013] [Indexed: 01/23/2023]
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Jebbett NJ, Hamilton JW, Rand MD, Eckenstein F. Low level methylmercury enhances CNTF-evoked STAT3 signaling and glial differentiation in cultured cortical progenitor cells. Neurotoxicology 2013; 38:91-100. [PMID: 23845766 DOI: 10.1016/j.neuro.2013.06.008] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Revised: 06/26/2013] [Accepted: 06/28/2013] [Indexed: 01/18/2023]
Abstract
Although many previous investigations have studied how mercury compounds cause cell death, sub-cytotoxic levels may affect mechanisms essential for the proper development of the nervous system. The present study investigates whether low doses of methylmercury (MeHg) and mercury chloride (HgCl2) can modulate the activity of JAK/STAT signaling, a pathway that promotes gliogenesis. We report that sub-cytotoxic doses of MeHg enhance ciliary neurotrophic factor (CNTF) evoked STAT3 phosphorylation in human SH-SY5Y neuroblastoma and mouse cortical neural progenitor cells (NPCs). This effect is specific for MeHg, since HgCl2 fails to enhance JAK/STAT signaling. Exposing NPCs to these low doses of MeHg (30-300nM) enhances CNTF-induced expression of STAT3-target genes such as glial fibrillary acidic protein (GFAP) and suppressors of cytokine signaling 3 (SOCS3), and increases the proportion of cells expressing GFAP following 2 days of differentiation. Higher, near-cytotoxic concentrations of MeHg and HgCl2 inhibit STAT3 phosphorylation and lead to increased production of superoxide. Lower concentrations of MeHg effective in enhancing JAK/STAT signaling (30nM) do not result in a detectable increase in superoxide nor increased expression of the oxidant-responsive genes, heme oxygenase 1, heat shock protein A5 and sirtuin 1. These findings suggest that low concentrations of MeHg inappropriately enhance STAT3 phosphorylation and glial differentiation, and that the mechanism causing this enhancement is distinct from the reactive oxygen species-associated cell death observed at higher concentrations of MeHg and HgCl2.
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Affiliation(s)
- Nathan J Jebbett
- University of Vermont, Department of Neurological Sciences, Burlington, VT, United States
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Zhang Y, Xing F, Zheng H, Xi J, Cui X, Xu Z. Roles of mitochondrial Src tyrosine kinase and zinc in nitric oxide-induced cardioprotection against ischemia/reperfusion injury. Free Radic Res 2013; 47:517-25. [DOI: 10.3109/10715762.2013.796044] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Ho NY, Yang L, Legradi J, Armant O, Takamiya M, Rastegar S, Strähle U. Gene responses in the central nervous system of zebrafish embryos exposed to the neurotoxicant methyl mercury. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2013; 47:3316-3325. [PMID: 23458150 DOI: 10.1021/es3050967] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Methyl mercury (MeHg) is a neurotoxicant with adverse effects on the development of the nervous system from fish to man. Despite a detailed understanding of the molecular mechanisms by which MeHg affects cellular homeostasis, it is still not clear how MeHg causes developmental neurotoxicity. We performed here a genome-wide transcriptional analysis of MeHg-exposed zebrafish embryos and combined this with a whole-mount in situ expression analysis of 88 MeHg-affected genes. The majority of the analyzed genes showed tissue- and region-restricted responses in various organs and tissues. The genes were linked to gene ontology terms like oxidative stress, transport and cell protection. Areas even within the central nervous system (CNS) are affected differently resulting in distinct cellular stress responses. Our study revealed an unexpected heterogeneity in gene responses to MeHg exposure in different tissues and neuronal subregions, even though the known molecular action of MeHg would predict a similar burden of exposed cells. The overall structure of the developing brain of MeHg-exposed embryos appeared normal, suggesting that the mechanism leading to differentiation of the CNS is not overtly affected by exposure to MeHg. We propose that MeHg disturbs the function of the CNS by disturbing the cellular homeostasis. As these cellular stress responses comprise genes that are also involved in normal neuronal activity and learning, MeHg may affect the developing CNS in a subtle manner that manifests itself in behavioral deficits.
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Affiliation(s)
- Nga Yu Ho
- Institute of Toxicology and Genetics, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany
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Shen W, Tian C, Chen H, Yang Y, Zhu D, Gao P, Liu J. Oxidative stress mediates chemerin-induced autophagy in endothelial cells. Free Radic Biol Med 2013. [PMID: 23195684 DOI: 10.1016/j.freeradbiomed.2012.11.011] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Chemerin is a novel adipokine associated with obesity and metabolic syndrome. Previous studies indicate that chemerin may also function as a stimulator of angiogenesis. However, the underlying mechanism of its regulatory role in angiogenesis remains largely unknown. In this study, we determined the role of autophagy in chemerin-induced angiogenesis. Treatment of human aorta endothelial cells (HAECs) with chemerin increased the generation of mitochondrial reactive oxygen species (ROS) concurrent with the induced, time-dependent expression of LC3II and upregulation of the autophagy-related genes beclin-1, Atg7, and Atg12-Atg5 . Knockdown of chemerin receptor 23 (ChemR23) by shRNA or treatment with the mitochondria-targeted antioxidant Mito-TEMPO decreased the chemerin-associated ROS generation and abolished the upregulation of autophagy-related genes. Furthermore, chemerin treatment of HAECs augmented AMP-activated protein kinase-α (AMPKα) activity and acetyl-CoA carboxylase phosphorylation and reduced phosphorylation of the mammalian target of rapamycin, ribosomal protein S6 kinase-1, and eukaryotic initiation factor 4E-binding protein 1, which were blocked by coadministration of Mito-TEMPO or shRNA-mediated knockdown of AMPKα. Analysis of the HAECs revealed that inhibition of autophagy by Mito-TEMPO or shRNA against ChemR23, AMPKα, and beclin-1 impaired chemerin-induced tube formation and cell proliferation. These studies show that mitochondrial ROS are important for autophagy in chemerin-induced angiogenesis and that targeting autophagy may provide an important new tool for treating cardiovascular disease.
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Affiliation(s)
- Weili Shen
- State Key Laboratory of Medical Genomics, Shanghai Key Laboratory of Vascular Biology and Department of Hypertension, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200025, People s Republic of China.
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Petroni D, Tsai J, Agrawal K, Mondal D, George W. Low-dose methylmercury-induced oxidative stress, cytotoxicity, and tau-hyperphosphorylation in human neuroblastoma (SH-SY5Y) cells. ENVIRONMENTAL TOXICOLOGY 2012; 27:549-555. [PMID: 21254321 DOI: 10.1002/tox.20672] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2010] [Revised: 10/12/2010] [Accepted: 10/15/2010] [Indexed: 05/28/2023]
Abstract
Acute neurotoxic effects of high-dose methylmercury (MeHg) in humans have been well documented in the scientific literature. However, low-dose effects are less well described. This study was designed to evaluate the effects of low-dose MeHg (<100 nM) on human brain cells in a tissue culture model. Neuroblastoma (NB) cells (SH-SY5Y) were used in the cell culture model to study low-dose effects of MeHg on cell growth, cell survival, reactive oxygen species (ROS), and the phosphorylation of tau protein, as a measure of potential markers of cellular events associated with tauopathies. When cells were incubated in culture with MeHg (50 and 100 nM), there were significant decreases in cell viability as well as significant increase in ROS generation as determined by fluorescent dye analysis (H(2)DCFDA). Furthermore, a concomitant decrease in glutathione levels to 25% of control was observed at both 50 and 100 nM MeHg. In addition, the level of phosphorylated tau was significantly increased after treatment at both 50 and 100 nM MeHg, compared with controls. Pretreatment of NB cells with the antioxidant, N-acetylcysteine (1.25 mM) and the calpain inhibitor, MDL-28170 (10 μM), significantly attenuated the effects of MeHg (50 and 100 nM) on cell viability as well as on tau phosphorylation. These results indicate that low-dose MeHg toxicity may be related to an induction of tau phosphorylation through an oxidative stress-dependent mechanism and that blockade of this pathway may attenuate the toxic effects of MeHg.
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Affiliation(s)
- Daniel Petroni
- Department of Pharmacology, Tulane University School of Medicine, New Orleans, Louisiana, USA
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Dokic I, Hartmann C, Herold-Mende C, Régnier-Vigouroux A. Glutathione peroxidase 1 activity dictates the sensitivity of glioblastoma cells to oxidative stress. Glia 2012; 60:1785-800. [PMID: 22951908 DOI: 10.1002/glia.22397] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2012] [Accepted: 07/03/2012] [Indexed: 01/02/2023]
Abstract
The high intratumoral and intertumoral heterogeneity of glioblastoma (GBM) leads to resistance to different therapies, and hence, selecting an effective therapy is very challenging. We hypothesized that the antioxidant enzyme status is a significant feature of GBM heterogeneity. The most important reactive oxygen/nitrogen species (ROS/RNS) detoxification mechanisms include superoxide dismutase (SOD), catalase, and glutathione peroxidase (GPx). Expression and activity of these enzymes and the cellular response to induced oxidative stress were systematically analyzed and compared between GBM cells and nontransformed glial cells of both human and murine origin. Regardless of cell type or species, all tested cells expressed similar amount of catalase and MnSOD. All except one, GBM cell lines exhibited a deficiency in GPx1 expression and activity. Analysis of GBM tissue sections indicated a heterogeneous profile of weak to moderate expression of GPx1 in tumor cells. GPx1 deficiency led to an accumulation of ROS/RNS and subsequent death of GBM cells after induction of oxidative stress. Astrocytes, microglia/macrophages, and glioma stem cell lines expressed active GPx1 and resisted ROS/RNS-mediated cell death. Pharmacological inhibition or siRNA silencing of GPx1 partially reverted this resistance in astrocytes, indicating the contribution of various antioxidant molecules besides GPx1. The GPx1-expressing GBM cell line on the contrary, became extremely sensitive to oxidative stress after GPx1 inhibition. Altogether, these results highlight GPx1 as a crucial element over other antioxidant enzymes for oxidative stress regulation in GBM cells. Mapping the antioxidant enzyme status of GBM may prove to be a useful tool for personalized ROS/RNS inducing therapies.
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Affiliation(s)
- Ivana Dokic
- INSERM U701, German Cancer Research Centre, Program Infection and Cancer, INF 242, Heidelberg, Germany
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Yang H, Xu Z, Liu W, Wei Y, Deng Y, Xu B. Effect of grape seed proanthocyanidin extracts on methylmercury-induced neurotoxicity in rats. Biol Trace Elem Res 2012; 147:156-64. [PMID: 22116679 DOI: 10.1007/s12011-011-9272-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2011] [Accepted: 11/13/2011] [Indexed: 10/15/2022]
Abstract
As a highly toxic environmental pollutant, methylmercury (MeHg) can cause neurotoxicity in animals and humans. Considering the antioxidant property of grape seed proanthocyanidin extracts (GSPE), this study was aimed to evaluate the effect of GSPE on MeHg-induced neurotoxicity in rats. Rats were exposed to MeHg by intraperitoneal injection (4, 12 μmol/kg, respectively) and GSPE was administered by gavage (250 mg/kg) 2 h later. After a 4-week treatment, phosphate-activated glutaminase, glutamine synthetase, glutathione peroxidase and superoxide dismutase activities, glutamate, glutamine, malondialdehyde and glutathione contents in cerebral cortex were measured. Reactive oxygen species (ROS) and apoptosis were also estimated in cells. The results showed that the MeHg-induced neurotoxicity was significantly attenuated. GSPE significantly decreased the production of ROS, counteracted oxidative damage and increased the antioxidants and antioxidant enzymes activities in rats prior to MeHg exposure. Moreover, the effects on the rate of apoptotic cells and the disturbance of glutamate homeostasis were correspondingly modulated. These observations highlighted the potential of GSPE in offering protection against MeHg-induced neurotoxicity.
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Affiliation(s)
- Haibo Yang
- Department of Environmental Health, School of Public Health, China Medical University, Shenyang, China
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43
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Fretham SJ, Caito S, Martinez-Finley EJ, Aschner M. Mechanisms and Modifiers of Methylmercury-Induced Neurotoxicity. Toxicol Res (Camb) 2012; 1:32-38. [PMID: 27795823 DOI: 10.1039/c2tx20010d] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The neurotoxic consequences of methylmercury (MeHg) exposure have long been known, however a complete understanding of the mechanisms underlying this toxicity is elusive. Recent epidemiological and experimental studies have provided many mechanistic insights, particularly into the contribution of genetic and environmental factors that interact with MeHg to modify toxicity. This review will outline cellular processes directly and indirectly affected by MeHg, including oxidative stress, cellular signaling and gene expression, and discuss genetic, environmental and nutritional factors capable of modifying MeHg toxicity.
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Affiliation(s)
- Stephanie Jb Fretham
- Department of Pediatrics and Department of Pharmacology, and the Kennedy Center for Research on Human Development, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Samuel Caito
- Department of Pediatrics and Department of Pharmacology, and the Kennedy Center for Research on Human Development, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Ebany J Martinez-Finley
- Department of Pediatrics and Department of Pharmacology, and the Kennedy Center for Research on Human Development, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Michael Aschner
- Department of Pediatrics and Department of Pharmacology, and the Kennedy Center for Research on Human Development, Vanderbilt University Medical Center, Nashville, TN, USA
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Minocycline protects cardiac myocytes against simulated ischemia–reperfusion injury by inhibiting poly(ADP-ribose) polymerase-1. J Cardiovasc Pharmacol 2012; 56:659-68. [PMID: 20881608 DOI: 10.1097/fjc.0b013e3181faeaf0] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
There is an increase in reactive oxygen and nitrogen species in cardiomyocytes during myocardial ischemia/reperfusion injury. This leads to oxidative DNA damage and activation of nuclear repair enzymes such as poly(ADP-ribose) polymerase-1 (PARP-1). PARP-1 activation promotes DNA repair under normal conditions. However, excessive activation of PARP-1 leads to cell death. We report that PARP-1 enzymatic activity is directly inhibited by minocycline, and we propose that one mechanism of minocycline cardioprotection is the result of PARP-1 inhibition. Using cultured adult rat cardiac myocytes, we evaluated the mechanism of minocycline protection in which PARP-1 activation was induced by simulated ischemia/reperfusion injury using oxygen–glucose deprivation.We found an increase in reactive oxygen species production, PARP-1 activation, and PARP-1-mediated cell death after simulated ischemia/reperfusion. Cell death was significantly reduced by the PARP inhibitors 3, 4-dihydro-5-[4-(1-piperidinyl)butoxy]-1(2H)-isoquinolinone (10 μM) and PJ-34 (500 nM) or by minocycline (500 nM). Cellular NAD(+) depletion and poly(ADP-ribose) formation, which are biochemical markers of PARP-1 activation, were also blocked by minocycline. Finally, simulated ischemia/reperfusion led to induction of the mitochondrial permeability transition, which was prevented by minocycline. Therefore, we propose that the protective effect of minocycline on cardiac myocyte survival is the result of inhibition of PARP-1 activity.
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Fujimura M, Usuki F. Differing effects of toxicants (methylmercury, inorganic mercury, lead, amyloid β, and rotenone) on cultured rat cerebrocortical neurons: differential expression of rho proteins associated with neurotoxicity. Toxicol Sci 2012; 126:506-14. [PMID: 22223485 DOI: 10.1093/toxsci/kfr352] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Methylmercury (MeHg), inorganic mercury (IHg), lead (Pb), amyloid-β peptide (Aβ), and rotenone (RTN) are well-known toxicants. Here, we demonstrate that these five toxicants exhibit differing effects on cerebrocortical neurons. The concentration responsible for 30% loss of viability (EC30) values 3 days after exposure was approximately 100nM for MeHg, IHg, and RTN and 10μM for Aβ. Neuritic degeneration and subsequent apoptotic cell death were observed in these toxicant-treated cells. In contrast, the EC30 value 3 days after exposure to Pb was > 10μM. We clarified the differential expression of Ras homolog gene (Rho) family proteins (Ras-related C3 botulinum toxin substrate 1 [Rac1], cell division cycle 42, and Ras homolog gene family, member A [RhoA]) upon exposure to these five toxicants. Exposure to 100nM MeHg, IHg, or RTN downregulated the expression of Rac1, related to neuritic extension, but did not affect RhoA, related to retraction. At a higher concentration (1μM), IHg and RTN also acted through the suppression of Rac1, whereas increased MeHg toxicity was not associated with the expression of Rho family proteins. On the other hand, Pb and Aβ showed no effects on the expression of Rho proteins. Modification of the balance of neuritic extension and retraction by the suppression of Rho A rescued the neurotoxicity of 100nM MeHg, IHg, and RTN. The results indicate that the imbalance of neuritic extension and retraction by the suppression of Rac1 by 100nM MeHg, IHg, and RTN causes cerebrocortical neuron axonal degeneration and cell death. By contrast, the neurotoxicities of Pb, Aβ, and MeHg (at higher concentrations) are conferred by other toxic mechanisms.
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Affiliation(s)
- Masatake Fujimura
- Department of Basic Medical Sciences, National Institute for Minamata Disease, 4058-18 Hama, Minamata, Kumamoto 867-0008, Japan.
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Farina M, Aschner M, Rocha JBT. Oxidative stress in MeHg-induced neurotoxicity. Toxicol Appl Pharmacol 2011; 256:405-17. [PMID: 21601588 PMCID: PMC3166649 DOI: 10.1016/j.taap.2011.05.001] [Citation(s) in RCA: 241] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2011] [Revised: 05/01/2011] [Accepted: 05/02/2011] [Indexed: 12/20/2022]
Abstract
Methylmercury (MeHg) is an environmental toxicant that leads to long-lasting neurological and developmental deficits in animals and humans. Although the molecular mechanisms mediating MeHg-induced neurotoxicity are not completely understood, several lines of evidence indicate that oxidative stress represents a critical event related to the neurotoxic effects elicited by this toxicant. The objective of this review is to summarize and discuss data from experimental and epidemiological studies that have been important in clarifying the molecular events which mediate MeHg-induced oxidative damage and, consequently, toxicity. Although unanswered questions remain, the electrophilic properties of MeHg and its ability to oxidize thiols have been reported to play decisive roles to the oxidative consequences observed after MeHg exposure. However, a close examination of the relationship between low levels of MeHg necessary to induce oxidative stress and the high amounts of sulfhydryl-containing antioxidants in mammalian cells (e.g., glutathione) have led to the hypothesis that nucleophilic groups with extremely high affinities for MeHg (e.g., selenols) might represent primary targets in MeHg-induced oxidative stress. Indeed, the inhibition of antioxidant selenoproteins during MeHg poisoning in experimental animals has corroborated this hypothesis. The levels of different reactive species (superoxide anion, hydrogen peroxide and nitric oxide) have been reported to be increased in MeHg-exposed systems, and the mechanisms concerning these increments seem to involve a complex sequence of cascading molecular events, such as mitochondrial dysfunction, excitotoxicity, intracellular calcium dyshomeostasis and decreased antioxidant capacity. This review also discusses potential therapeutic strategies to counteract MeHg-induced toxicity and oxidative stress, emphasizing the use of organic selenocompounds, which generally present higher affinity for MeHg when compared to the classically studied agents.
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Affiliation(s)
- Marcelo Farina
- Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianópolis, SC, Brazil
| | - Michael Aschner
- Department of Pediatrics and Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - João B. T. Rocha
- Departamento de Química, Centro de Ciências Naturais e Exatas, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
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Meinerz D, de Paula M, Comparsi B, Silva M, Schmitz A, Braga H, Taube P, Braga A, Rocha J, Dafre A, Farina M, Franco J, Posser T. Protective effects of organoselenium compounds against methylmercury-induced oxidative stress in mouse brain mitochondrial-enriched fractions. Braz J Med Biol Res 2011; 44:1156-63. [DOI: 10.1590/s0100-879x2011007500136] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2011] [Accepted: 09/21/2011] [Indexed: 11/21/2022] Open
Affiliation(s)
| | | | | | - M.U. Silva
- Universidade Federal de Santa Maria, Brasil
| | | | - H.C. Braga
- Universidade Federal de Santa Maria, Brasil
| | - P.S. Taube
- Universidade Federal de Santa Maria, Brasil
| | - A.L. Braga
- Universidade Federal de Santa Maria, Brasil
| | | | - A.L. Dafre
- Universidade Federal de Santa Maria, Brasil
| | - M. Farina
- Universidade Federal de Santa Maria, Brasil
| | - J.L. Franco
- Universidade Federal do Pampa, Brasil; Universidade Federal de Santa Maria, Brasil
| | - T. Posser
- Universidade Federal do Pampa, Brasil; Universidade Federal de Santa Maria, Brasil
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48
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Role of oxidative stress and the mitochondrial permeability transition in methylmercury cytotoxicity. Neurotoxicology 2011; 32:526-34. [PMID: 21871920 DOI: 10.1016/j.neuro.2011.07.006] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2011] [Revised: 07/13/2011] [Accepted: 07/13/2011] [Indexed: 01/24/2023]
Abstract
Oxidative stress has been implicated in the pathogenesis of methylmercury (MeHg) neurotoxicity. Studies of mature neurons suggest that the mitochondrion may be a major source of MeHg-induced reactive oxygen species and a critical mediator of MeHg-induced neuronal death, likely by activation of apoptotic pathways. It is unclear, however, whether the mitochondria of developing and mature neurons are equally susceptible to MeHg. Murine embryonal carcinoma (EC) cells, which differentiate into neurons following exposure to retinoic acid, were used to compare the differentiation-dependent effects of MeHg on ROS production and mitochondrial depolarization. EC cells and their neuronal derivatives were pre-incubated with the ROS indicator 2',7'-dichlorofluoroscein diacetate or tetramethylrhodamine methyl ester, an indicator of mitochondrial membrane potential, with or without cyclosporin A (CsA), an inhibitor of mitochondrial permeability transition pore opening, and examined by laser scanning confocal microscopy in the presence of 1.5 μM MeHg. To examine consequences of mitochondrial perturbation, immunohistochemical localization of cytochrome c (cyt c) was determined after incubation of cells in MeHg for 4 h. MeHg treatment induced earlier and significantly higher levels of ROS production and more extensive mitochondrial depolarization in neurons than in undifferentiated EC cells. CsA completely inhibited mitochondrial depolarization by MeHg in EC cells but only delayed this response in the neurons. In contrast, CsA significantly inhibited MeHg-induced neuronal ROS production. Cyt c release was also more extensive in neurons, with less protection afforded by CsA. These data indicate that neuronal differentiation state influences mitochondrial transition pore dynamics and MeHg-stimulated production of ROS.
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49
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Yin Z, Lee E, Ni M, Jiang H, Milatovic D, Rongzhu L, Farina M, Rocha JBT, Aschner M. Methylmercury-induced alterations in astrocyte functions are attenuated by ebselen. Neurotoxicology 2011; 32:291-9. [PMID: 21300091 PMCID: PMC3079013 DOI: 10.1016/j.neuro.2011.01.004] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2010] [Revised: 12/21/2010] [Accepted: 01/08/2011] [Indexed: 12/26/2022]
Abstract
Methylmercury (MeHg) preferentially accumulates in glia of the central nervous system (CNS), but its toxic mechanisms have yet to be fully recognized. In the present study, we tested the hypothesis that MeHg induces neurotoxicity via oxidative stress mechanisms, and that these effects are attenuated by the antioxidant, ebselen. Rat neonatal primary cortical astrocytes were pretreated with or without 10 μM ebselen for 2h followed by MeHg (0, 1, 5, and 10 μM) treatments. MeHg-induced changes in astrocytic [(3)H]-glutamine uptake were assessed along with changes in mitochondrial membrane potential (ΔΨ(m)), using the potentiometric dye tetramethylrhodamine ethyl ester (TMRE). Western blot analysis was used to detect MeHg-induced ERK (extracellular-signal related kinase) phosphorylation and caspase-3 activation. MeHg treatment significantly decreased (p<0.05) astrocytic [(3)H]-glutamine uptake at all time points and concentrations. Ebselen fully reversed MeHg's (1 μM) effect on [(3)H]-glutamine uptake at 1 min. At higher MeHg concentrations, ebselen partially reversed the MeHg-induced astrocytic inhibition of [(3)H]-glutamine uptake [at 1 min (5 and 10 μM) (p<0.05); 5 min (1, 5 and 10 μM) (p<0.05)]. MeHg treatment (1h) significantly (p<0.05) dissipated the ΔΨ(m) in astrocytes as evidenced by a decrease in mitochondrial TMRE fluorescence. Ebselen fully reversed the effect of 1 μM MeHg treatment for 1h on astrocytic ΔΨ(m) and partially reversed the effect of 5 and 10 μM MeHg treatments for 1h on ΔΨ(m). In addition, ebselen inhibited MeHg-induced phosphorylation of ERK (p<0.05) and blocked MeHg-induced activation of caspase-3 (p<0.05-0.01). These results are consistent with the hypothesis that MeHg exerts its toxic effects via oxidative stress and that the phosphorylation of ERK and the dissipation of the astrocytic mitochondrial membrane potential are involved in MeHg toxicity. In addition, the protective effects elicited by ebselen reinforce the idea that organic selenocompounds represent promising strategies to counteract MeHg-induced neurotoxicity.
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MESH Headings
- Analysis of Variance
- Animals
- Animals, Newborn
- Antioxidants/pharmacology
- Astrocytes/drug effects
- Astrocytes/metabolism
- Astrocytes/pathology
- Azoles/pharmacology
- Blotting, Western
- Caspase 3/metabolism
- Cells, Cultured
- Cytoprotection
- Dose-Response Relationship, Drug
- Environmental Pollutants/toxicity
- Extracellular Signal-Regulated MAP Kinases/metabolism
- Glutamine/metabolism
- Isoindoles
- Membrane Potential, Mitochondrial/drug effects
- Mercury Poisoning, Nervous System/etiology
- Mercury Poisoning, Nervous System/metabolism
- Mercury Poisoning, Nervous System/pathology
- Methylmercury Compounds/toxicity
- Microscopy, Fluorescence
- Mitochondria/drug effects
- Mitochondria/metabolism
- Neuroprotective Agents/pharmacology
- Organoselenium Compounds/pharmacology
- Oxidative Stress/drug effects
- Phosphorylation
- Rats
- Rats, Sprague-Dawley
- Time Factors
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Affiliation(s)
- Zhaobao Yin
- Departments of Pediatrics and Pharmacology, the Kennedy Center for Research on Human Development, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Eunsook Lee
- Department of Physiology, Meharry Medical College, Nashville, Tennessee
| | - Mingwei Ni
- Departments of Pediatrics and Pharmacology, the Kennedy Center for Research on Human Development, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Haiyan Jiang
- Departments of Pediatrics and Pharmacology, the Kennedy Center for Research on Human Development, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Dejan Milatovic
- Departments of Pediatrics and Pharmacology, the Kennedy Center for Research on Human Development, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Lu Rongzhu
- Departments of Pediatrics and Pharmacology, the Kennedy Center for Research on Human Development, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Marcelo Farina
- Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianópolis, SC, Brazil
| | - Joao B. T. Rocha
- Departamento de Bioquímica, Universidade Federal de Santa Maria, Santa Maria, RS, Brazil
| | - Michael Aschner
- Departments of Pediatrics and Pharmacology, the Kennedy Center for Research on Human Development, Vanderbilt University Medical Center, Nashville, Tennessee
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Shao ZH, Wojcik KR, Qin Y, Li CQ, Hoek TLV, Hamann KJ. Blockade of Caspase-2 Activity Inhibits Ischemia/Reperfusion-Induced Mitochondrial Reactive Oxygen Burst and Cell Death in Cardiomyocytes. J Cell Death 2011. [DOI: 10.4137/jcd.s6723] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
We previously showed that initiator caspases-2 and −8 are prominently activated in ischemia/reperfusion (I/R)-induced injury in cardiomyocytes, but while blockade of caspase-2 activity enhanced cell survival, blockade of caspase-8 activity did not protect cardiomyocytes. Because apoptotic death in these cells is characterized by a burst of reactive oxygen species (ROS) at reperfusion and their survival by inhibition of this burst, we examined the effects of blocking caspase-2 and caspase-8 activities on ROS production. Caspase-2 inhibition blocked the reperfusion-induced ROS burst, while inhibition of caspase-8 did not. We also examined effects of caspase inhibition on mitochondrial membrane potential (ΔΨm) and mitochondrial function and found that blocking caspase-2, but not caspase-8, allowed recovery of ΔΨm and mitochondrial functionality. Furthermore, knockdown of caspase-2 by small-interfering (si)RNA confirmed caspase-2 participation in cytochrome c release, which correlates with loss of ΔΨm and cell death in these cardiomyocytes.
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Affiliation(s)
- Zuo-Hui Shao
- Emergency Medicine, Department of Medicine and The emergency resuscitation Center, The University of Chicago, Chicago, IL 60637, USA
| | | | - Yimin Qin
- Sections of Pulmonary and Critical Care Medicine
| | - Chang-Qing Li
- Emergency Medicine, Department of Medicine and The emergency resuscitation Center, The University of Chicago, Chicago, IL 60637, USA
| | - Terry L. Vanden Hoek
- Emergency Medicine, Department of Medicine and The emergency resuscitation Center, The University of Chicago, Chicago, IL 60637, USA
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