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Kang B, Wang J, Guo S, Yang L. Mercury-induced toxicity: Mechanisms, molecular pathways, and gene regulation. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 943:173577. [PMID: 38852866 DOI: 10.1016/j.scitotenv.2024.173577] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 03/01/2024] [Accepted: 05/25/2024] [Indexed: 06/11/2024]
Abstract
Mercury is a well-known neurotoxicant for humans and wildlife. The epidemic of mercury poisoning in Japan has clearly demonstrated that chronic exposure to methylmercury (MeHg) results in serious neurological damage to the cerebral and cerebellar cortex, leading to the dysfunction of the central nervous system (CNS), especially in infants exposed to MeHg in utero. The occurrences of poisoning have caused a wide public concern regarding the health risk emanating from MeHg exposure; particularly those eating large amounts of fish may experience the low-level and long-term exposure. There is growing evidence that MeHg at environmentally relevant concentrations can affect the health of biota in the ecosystem. Although extensive in vivo and in vitro studies have demonstrated that the disruption of redox homeostasis and microtube assembly is mainly responsible for mercurial toxicity leading to adverse health outcomes, it is still unclear whether we could quantitively determine the occurrence of interaction between mercurial and thiols and/or selenols groups of proteins linked directly to outcomes, especially at very low levels of exposure. Furthermore, intracellular calcium homeostasis, cytoskeleton, mitochondrial function, oxidative stress, neurotransmitter release, and DNA methylation may be the targets of mercury compounds; however, the primary targets associated with the adverse outcomes remain to be elucidated. Considering these knowledge gaps, in this article, we conducted a comprehensive review of mercurial toxicity, focusing mainly on the mechanism, and genes/proteins expression. We speculated that comprehensive analyses of transcriptomics, proteomics, and metabolomics could enhance interpretation of "omics" profiles, which may reveal specific biomarkers obviously correlated with specific pathways that mediate selective neurotoxicity.
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Affiliation(s)
- Bolun Kang
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, 100012 Beijing, China
| | - Jinghan Wang
- 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
| | - Lixin Yang
- State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, 100012 Beijing, China.
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Sales MVS, Barros EDSS, Azevedo RDS, Cunha FAS, Santos JCC, Leite ACR. Does acute exposure to thimerosal, an organic mercury compound, affect the mitochondrial function of an infant model? J Trace Elem Med Biol 2024; 83:127399. [PMID: 38325180 DOI: 10.1016/j.jtemb.2024.127399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2023] [Revised: 01/19/2024] [Accepted: 01/20/2024] [Indexed: 02/09/2024]
Abstract
BACKGROUND Thimerosal (TM) is a toxic, organometallic mercury compound (which releases ethyl-mercury-containing compounds in aqueous solutions) used as a preservative in vaccines. Mitochondria are organelle which are highly vulnerable to many chemical compounds, including mercury (Hg) and its derivatives. METHOD Wistar rats (at 21 days of age) were used to model a child's TM exposure following childhood vaccination, divided in two groups: TM exposed (20 μg/kg/day) and unexposed controls (saline solution), both for 24 h. Atomic Fluorescence Spectrometry was used to quantify the amounts of mercury in tissues. The electron transport chain (ETC) from isolated mitochondria was evaluated using an oxygen electrode. The mitochondrial membrane potential and H2O2 production were analyzed using selective fluorescence probes. The activity of some enzymes (SOD, CAT, GPx, and AChE) and secondary markers of oxidative stress (GSH, GSSG, total free thiol) were also examined in tissues. RESULTS Hg accumulation in the brain and liver was higher in exposed animals when compared to the control. Liver-isolated mitochondria showed that TM improved respiratory control by 23%; however, states 3 and 4 of the ETC presented a decrease of 16% and 37%, respectively. Furthermore, brain-isolated mitochondria presented an improvement of 61% in respiratory control. Brain enzyme activities were significantly impacted in TM-exposed rats compared to unexposed rats as follows: decreases in SOD (32%) and AChE (42%) and increases in GPx (79%) and CAT (100%). GPx enzyme activity in the liver was significantly increased (37%). Among secondary oxidative stress markers, the brain's total reduced thiol (SH) concentration was significantly increased (41%). CONCLUSION Acute TM treatment exposure in a Wistar rat model mimicking TM exposure in an infant following childhood vaccination significantly damaged brain bioenergetic pathways. This study supports the ability of TM exposure to preferentially damage the nervous system.
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Affiliation(s)
- Marcos V S Sales
- Universidade Federal de Alagoas (UFAL), Campus A. C. Simões, 57072-900 Maceió, Alagoas, Brazil
| | | | - Rafael D S Azevedo
- Universidade de Pernambuco (UPE), Campus Garanhuns, 55294-902 São José, Pernambuco, Brazil
| | - Francisco A S Cunha
- Instituto de Química, Universidade Federal da Bahia (UFBA), Campus Ondina, 40170-115 Salvador, Bahia, Brazil
| | | | - Ana C R Leite
- Universidade Federal de Alagoas (UFAL), Campus A. C. Simões, 57072-900 Maceió, Alagoas, Brazil.
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Li X, Kong L, Pan J, Liu H, Wang C, Xu S, Liu W, Sun J. N-acetylcysteine protects against neurodevelopmental injuries induced by methylmercury exposure during pregnancy and lactation. Brain Res 2024; 1827:148761. [PMID: 38211826 DOI: 10.1016/j.brainres.2024.148761] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Revised: 01/07/2024] [Accepted: 01/08/2024] [Indexed: 01/13/2024]
Abstract
As an extremely dangerous environmental contaminant, methylmercury (MeHg) results in detrimental health effects in human brain nervous system, one of its main targets. However, as a developmental toxicant, the brain of offspring is vulnerable to MeHg during pregnancy and lactation exposure. Unfortunately, mechanisms of neurodevelopmental injuries induced by MeHg have not been fully elucidated. N-acetylcysteine (NAC) has been used for several decades as an antioxidant to antagonize oxidative stress. However, the molecular mechanisms of NAC alleviating MeHg-induced neurodevelopmental toxicity are not clear. Here, for evaluation of the dose-dependent effects of MeHg exposure on neurodevelopmental injuries of offspring, and the possible protective effects of NAC, the pregnant female mice were exposed to MeHg (4, 8, 12 mg/L, respectively) and NAC (50, 100, 150 mg/kg, respectively) from gestational day 1 (GD1) to postnatal day 21 (PND21). Our results indicated that administering MeHg caused behavioral impairment and neuronal injuries in the cerebral cortex of newborn mice. MeHg dose-dependently caused reactive oxygen species (ROS) overproduction and oxidative stress aggravation, together with expression of Nrf2, HO-1, Notch1, and p21 up-regulation, and CDK2 inhibition. NAC treatment dose-dependently antagonized MeHg-induced oxidative stress that may contribute to alleviating neurobehavioral and neurodevelopmental impairments. These results give insight into that NAC can protect against MeHg-induced neurodevelopmental toxicity by its antioxidation capacity.
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Affiliation(s)
- Xiaoyang Li
- Department of Environmental Health, School of Public Health, China Medical University, Shenyang, PR China
| | - Lingxu Kong
- Department of Environmental Health, School of Public Health, China Medical University, Shenyang, PR China
| | - Jingjing Pan
- Department of Environmental Health, School of Public Health, China Medical University, Shenyang, PR China
| | - Haihui Liu
- Department of Environmental Health, School of Public Health, China Medical University, Shenyang, PR China
| | - Chen Wang
- Department of Environmental Health, School of Public Health, China Medical University, Shenyang, PR China
| | - Si Xu
- Department of Environmental Health, School of Public Health, China Medical University, Shenyang, PR China
| | - Wei Liu
- Department of Environmental Health, School of Public Health, China Medical University, Shenyang, PR China
| | - Jingyi Sun
- Department of Cardiology, The Second Hospital of Dalian Medical University, Dalian, Liaoning, PR China.
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Lee CK, Wang FT, Huang CH, Chan WH. Prevention of methylmercury-triggered ROS-mediated impairment of embryo development by co-culture with adult adipose-derived mesenchymal stem cells. Toxicol Res (Camb) 2024; 13:tfad122. [PMID: 38162594 PMCID: PMC10753290 DOI: 10.1093/toxres/tfad122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Revised: 10/19/2023] [Accepted: 12/08/2023] [Indexed: 01/03/2024] Open
Abstract
Methylmercury (MeHg) is a potent toxin that exerts deleterious effects on human health via environmental contamination. Significant effects of MeHg on neuronal development in embryogenesis have been reported. Recently, our group demonstrated that MeHg exerts toxic effects on pre- and post-implantation embryonic development processes from zygote to blastocyst stage. Our results showed that MeHg impairs embryo development by induction of apoptosis through reactive oxygen species (ROS) generation that triggers caspase-3 cleavage and activation, which, in turn, stimulates p21-activated kinase 2 (PAK2) activity. Importantly, ROS were identified as a key upstream regulator of apoptotic events in MeHg-treated blastocysts. Data from the current study further confirmed that MeHg exerts hazardous effects on cell proliferation, apoptosis, implantation, and pre- and post-implantation embryo development. Notably, MeHg-induced injury was markedly prevented by co-culture with adipose-derived mesenchymal stem cells (ADMSCs) in vitro. Furthermore, ADMSC injection significantly reduced MeHg-mediated deleterious effects on embryo, placenta, and fetal development in vivo. Further investigation of the regulatory mechanisms by which co-cultured ADMSCs could prevent MeHg-induced impairment of embryo development revealed that ADMSCs effectively reduced ROS generation and its subsequent downstream apoptotic events, including loss of mitochondrial membrane potential and activation of caspase-3 and PAK2. The collective findings indicate that co-culture with mesenchymal stem cells (MSCs) or utilization of MSC-derived cell-conditioned medium offers an effective potential therapeutic strategy to prevent impairment of embryo development by MeHg.
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Affiliation(s)
- Cheng-Kai Lee
- Department of Obstetrics and Gynecology, Taoyuan General Hospital, Ministry of Health & Welfare, Zhongshan Road, Taoyuan District, Taoyuan City 33004, Taiwan
| | - Fu-Ting Wang
- Rehabilitation and Technical Aid Center, Taipei Veterans General Hospital, Section 2, Shipai Road, Beitou District, Taipei City 11217, Taiwan
| | - Chien-Hsun Huang
- Hungchi Gene IVF Center, Daxing West Road, Taoyuan District, Taoyuan City 330012, Taiwan
| | - Wen-Hsiung Chan
- Department of Bioscience Technology and Center for Nanotechnology, Chung Yuan Christian University, Zhongbei Road, Zhongli District, Taoyuan City 32023, Taiwan
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Wei R, Wei P, Yuan H, Yi X, Aschner M, Jiang YM, Li SJ. Inflammation in Metal-Induced Neurological Disorders and Neurodegenerative Diseases. Biol Trace Elem Res 2024:10.1007/s12011-023-04041-z. [PMID: 38206494 DOI: 10.1007/s12011-023-04041-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Accepted: 12/23/2023] [Indexed: 01/12/2024]
Abstract
Essential metals play critical roles in maintaining human health as they participate in various physiological activities. Nonetheless, both excessive accumulation and deficiency of these metals may result in neurotoxicity secondary to neuroinflammation and the activation of microglia and astrocytes. Activation of these cells can promote the release of pro-inflammatory cytokines. It is well known that neuroinflammation plays a critical role in metal-induced neurotoxicity as well as the development of neurological disorders, such as Alzheimer's disease (AD), Parkinson's disease (PD), and multiple sclerosis (MS). Initially seen as a defense mechanism, persistent inflammatory responses are now considered harmful. Astrocytes and microglia are key regulators of neuroinflammation in the central nervous system, and their excessive activation may induce sustained neuroinflammation. Therefore, in this review, we aim to emphasize the important role and molecular mechanisms underlying metal-induced neurotoxicity. Our objective is to raise the awareness on metal-induced neuroinflammation in neurological disorders. However, it is not only just neuroinflammation that different metals could induce; they can also cause harm to the nervous system through oxidative stress, apoptosis, and autophagy, to name a few. The primary pathophysiological mechanism by which these metals induce neurological disorders remains to be determined. In addition, given the various pathways through which individuals are exposed to metals, it is necessary to also consider the effects of co-exposure to multiple metals on neurological disorders.
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Affiliation(s)
- Ruokun Wei
- Toxicology Department, School of Public Health, Guangxi Medical University, 22 Shuang-yong Rd., Nanning, 530021, China
- Guangxi Key Laboratory of Environment and Health Research, Guangxi Medical University, 22 Shuang-yong Rd., Nanning, 530021, Guangxi, China
| | - Peiqi Wei
- Toxicology Department, School of Public Health, Guangxi Medical University, 22 Shuang-yong Rd., Nanning, 530021, China
- Guangxi Key Laboratory of Environment and Health Research, Guangxi Medical University, 22 Shuang-yong Rd., Nanning, 530021, Guangxi, China
| | - Haiyan Yuan
- Toxicology Department, School of Public Health, Guangxi Medical University, 22 Shuang-yong Rd., Nanning, 530021, China
- Guangxi Key Laboratory of Environment and Health Research, Guangxi Medical University, 22 Shuang-yong Rd., Nanning, 530021, Guangxi, China
| | - Xiang Yi
- Toxicology Department, School of Public Health, Guangxi Medical University, 22 Shuang-yong Rd., Nanning, 530021, China
- Guangxi Key Laboratory of Environment and Health Research, Guangxi Medical University, 22 Shuang-yong Rd., Nanning, 530021, Guangxi, China
| | - Michael Aschner
- The Department of Molecular Pharmacology at Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Yue-Ming Jiang
- Toxicology Department, School of Public Health, Guangxi Medical University, 22 Shuang-yong Rd., Nanning, 530021, China.
- Guangxi Key Laboratory of Environment and Health Research, Guangxi Medical University, 22 Shuang-yong Rd., Nanning, 530021, Guangxi, China.
| | - Shao-Jun Li
- Toxicology Department, School of Public Health, Guangxi Medical University, 22 Shuang-yong Rd., Nanning, 530021, China.
- Guangxi Key Laboratory of Environment and Health Research, Guangxi Medical University, 22 Shuang-yong Rd., Nanning, 530021, Guangxi, China.
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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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Lee CK, Wang FT, Huang CH, Chan WH. Role of activated p21-activated kinase 2 in methylmercury-induced embryotoxic effects on mouse blastocysts. Toxicol Res (Camb) 2023; 12:433-445. [PMID: 37397923 PMCID: PMC10311136 DOI: 10.1093/toxres/tfad030] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 03/09/2023] [Accepted: 04/06/2023] [Indexed: 07/04/2023] Open
Abstract
Methylmercury (MeHg), a biotransformation product derived from mercury or inorganic mercury compounds in waterways, is a potent toxin that exerts hazardous effects on human health via environmental contamination. Previous studies have reported MeHg-induced impairment of nerve development in embryogenesis and placental development. However, the potential deleterious effects and regulatory mechanisms of action of MeHg on pre- and post-implantation embryo development are yet to be established. Experiments from the current study clearly demonstrate that MeHg exerts toxic effects on early embryonic development processes, including the zygote to blastocyst stage. Induction of apoptosis and decrease in embryo cell number were clearly detected in MeHg-treated blastocysts. Additionally, intracellular reactive oxygen species (ROS) generation and activation of caspase-3 and p21-activated protein kinase 2 (PAK2) were observed in MeHg-treated blastocysts. Importantly, prevention of ROS generation by pre-treatment with Trolox, a potent antioxidant, significantly attenuated MeHg-triggered caspase-3 and PAK2 activation as well as apoptosis. Notably, the downregulation of PAK2 via transfection of specifically targeted siRNA (siPAK2) led to marked attenuation of PAK2 activity and apoptosis and the deleterious effects of MeHg on embryonic development in blastocysts. Our findings strongly suggest that ROS serve as an important upstream regulator to trigger the activation of caspase-3, which further cleaves and activates PAK2 in MeHg-treated blastocysts. Activated PAK2 promotes apoptotic processes that, in turn, cause sequent impairment of embryonic and fetal development.
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Affiliation(s)
- Cheng-Kai Lee
- Department of Obstetrics and Gynecology, Taoyuan General Hospital, Ministry of Health & Welfare, Taoyuan City 33004, Taiwan
| | - Fu-Ting Wang
- Rehabilitation and Technical Aid Center, Taipei Veterans General Hospital, Taipei City 11217, Taiwan
| | - Chien-Hsun Huang
- Hungchi Gene IVF Center, Taoyuan District, Taoyuan City 330012, Taiwan
| | - Wen-Hsiung Chan
- Corresponding author: Department of Bioscience Technology and Center for Nanotechnology, Chung Yuan Christian University, Chung Li District, Taoyuan City 32023, Taiwan. Fax: +886-3-2653599; E-mail:
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Zuo K, Xu Q, Wang Y, Sui Y, Niu Y, Liu Z, Liu M, Liu X, Liu D, Sun W, Wang Z, Liu X, Liu J. L-Ascorbic Acid 2-Phosphate Attenuates Methylmercury-Induced Apoptosis by Inhibiting Reactive Oxygen Species Accumulation and DNA Damage in Human SH-SY5Y Cells. TOXICS 2023; 11:144. [PMID: 36851019 PMCID: PMC9967424 DOI: 10.3390/toxics11020144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 01/28/2023] [Accepted: 01/31/2023] [Indexed: 06/18/2023]
Abstract
Methylmercury (MeHg) is a toxin that causes severe neuronal oxidative damage. As vitamin C is an antioxidant well-known to protect neurons from oxidative damage, our goal was to elucidate its protective mechanism against MeHg-induced oxidative stress in human neuroblastomas (SHSY5Y). We treated cells with MeHg, L-ascorbic acid 2-phosphate (AA2P), or both, and used MTT, flow cytometry, and Western blot analyses to assess cell damage. We found that MeHg significantly decreased the survival rate of SH-SY5Y cells in a time- and dose-dependent manner, increased apoptosis, downregulated PAR and PARP1 expression, and upregulated AIF, Cyto C, and cleaved Caspase-3 expression. A time course study showed that MeHg increased reactive oxygen species (ROS) accumulation; enhanced apoptosis; increased DNA damage; upregulated expression ofγH2A.X, KU70, 67 and 57 kDa AIF, CytoC, and cleaved Caspase-3; and downregulated expression of 116 kDa PARP1, PAR, BRAC1, and Rad51. Supplementation with AA2P significantly increased cell viability and decreased intrinsic ROS accumulation. It also reduced ROS accumulation in cells treated with MeHg and decreased MeHg-induced apoptosis. Furthermore, AA2P conversely regulated gene expression compared to MeHg. Collectively, we demonstrate that AA2P attenuates MeHg-induced apoptosis by alleviating ROS-mediated DNA damage and is a potential treatment for MeHg neurotoxicity.
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Affiliation(s)
- Kuiyang Zuo
- Department of Toxicology, School of Public Health, Jilin University, 1163 Xinmin Avenue, Changchun 130021, China
| | - Qi Xu
- Department of Toxicology, School of Public Health, Jilin University, 1163 Xinmin Avenue, Changchun 130021, China
| | - Yujie Wang
- Department of Toxicology, School of Public Health, Jilin University, 1163 Xinmin Avenue, Changchun 130021, China
| | - Yutong Sui
- Department of Toxicology, School of Public Health, Jilin University, 1163 Xinmin Avenue, Changchun 130021, China
| | - Ye Niu
- Department of Toxicology, School of Public Health, Jilin University, 1163 Xinmin Avenue, Changchun 130021, China
| | - Zinan Liu
- Department of Toxicology, School of Public Health, Jilin University, 1163 Xinmin Avenue, Changchun 130021, China
| | - Mingsheng Liu
- Department of Toxicology, School of Public Health, Jilin University, 1163 Xinmin Avenue, Changchun 130021, China
| | - Xinpeng Liu
- Department of Toxicology, School of Public Health, Jilin University, 1163 Xinmin Avenue, Changchun 130021, China
| | - Dan Liu
- Department of Toxicology, School of Public Health, Jilin University, 1163 Xinmin Avenue, Changchun 130021, China
| | - Wei Sun
- Department of Toxicology, School of Public Health, Jilin University, 1163 Xinmin Avenue, Changchun 130021, China
| | - Ziyu Wang
- Department of Toxicology, School of Public Health, Jilin University, 1163 Xinmin Avenue, Changchun 130021, China
| | - Xiaomei Liu
- Department of Toxicology, School of Public Health, Jilin University, 1163 Xinmin Avenue, Changchun 130021, China
| | - Jinyu Liu
- Department of Toxicology, School of Public Health, Jilin University, 1163 Xinmin Avenue, Changchun 130021, China
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Zhang X, Hao H, Ma K, Pang H, Li X, Tian T, Hou S, Ning X, Wu H, Hou Q, Li M, Sun Y, Song X, Jin M. The role and mechanism of unfolded protein response signaling pathway in methylmercury-induced apoptosis of mouse spermatocytes germ cell-2 cells. ENVIRONMENTAL TOXICOLOGY 2023; 38:472-482. [PMID: 36330985 DOI: 10.1002/tox.23684] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Revised: 10/09/2022] [Accepted: 10/13/2022] [Indexed: 06/16/2023]
Abstract
The study aimed to explore the role and mechanism of unfolded protein response (UPR) in methylmercury (MeHg)-induced Mouse Spermatocytes (GC-2spd[ts]) apoptosis. Methods such as MTT, flow cytometry, and Western Blot were used to evaluate the cell viability, membrane potential (MMP), reactive oxygen species (ROS), calcium ion (Ca2+ ), rate of cell apoptosis, and the expression of apoptosis-related and UPR-related protein. The results showed that with the increase of MeHg concentration, cell viability and MMP decreased, ROS, Ca2+ , rate of cell apoptosis, and the expression of apoptosis-related protein and UPR-related protein increased. To further explore the effect of ROS-induced oxidative damage on it, the ROS inhibitor N-acetyl-L-cysteine (NAC) was used. The effects of MeHg on germ cell (GC-2) cells were partially inhibited after NAC pretreatment. Our present study proved that MeHg might induce cell apoptosis by activating the UPR signaling pathway in GC-2 cells and affect normal reproductive function.
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Affiliation(s)
- Xiayu Zhang
- School of Public Health, Jilin University, Changchun, People's Republic of China
| | - Huifang Hao
- School of Public Health, Jilin University, Changchun, People's Republic of China
| | - Kai Ma
- School of Public Health, Jilin University, Changchun, People's Republic of China
| | - Huan Pang
- School of Public Health, Jilin University, Changchun, People's Republic of China
| | - Xinyue Li
- School of Public Health, Jilin University, Changchun, People's Republic of China
| | - Tiantian Tian
- School of Public Health, Jilin University, Changchun, People's Republic of China
| | - Shanshan Hou
- School of Public Health, Jilin University, Changchun, People's Republic of China
| | - Xiaofan Ning
- School of Public Health, Jilin University, Changchun, People's Republic of China
| | - Hao Wu
- School of Public Health, Jilin University, Changchun, People's Republic of China
| | - Qiaohong Hou
- School of Public Health, Jilin University, Changchun, People's Republic of China
| | - Meng Li
- School of Public Health, Jilin University, Changchun, People's Republic of China
| | - Yunxiang Sun
- School of Public Health, Jilin University, Changchun, People's Republic of China
| | - Xiuling Song
- School of Public Health, Jilin University, Changchun, People's Republic of China
| | - Minghua Jin
- School of Public Health, Jilin University, Changchun, People's Republic of China
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Alterations in UPR Signaling by Methylmercury Trigger Neuronal Cell Death in the Mouse Brain. Int J Mol Sci 2022; 23:ijms232315412. [PMID: 36499738 PMCID: PMC9738736 DOI: 10.3390/ijms232315412] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 11/29/2022] [Accepted: 12/03/2022] [Indexed: 12/12/2022] Open
Abstract
Methylmercury (MeHg), an environmental toxicant, induces neuronal cell death and injures specific areas of the brain. MeHg is known to induce oxidative and endoplasmic reticulum (ER) stress. The unfolded protein response (UPR) pathway has a dual nature in that it regulates and protects cells from an overload of improperly folded proteins in the ER, whereas excessively stressed cells are eliminated by apoptosis. Oxidative stress/ER stress induced by methylmercury exposure may tilt the UPR toward apoptosis, but there is little in vivo evidence of a direct link to actual neuronal cell death. Here, by using the ER stress-activated indicator (ERAI) system, we investigated the time course signaling alterations of UPR in vivo in the most affected areas, the somatosensory cortex and striatum. In the ERAI-Venus transgenic mice exposed to MeHg (30 or 50 ppm in drinking water), the ERAI signal, which indicates the activation of the cytoprotective pathway of the UPR, was only transiently enhanced, whereas the apoptotic pathway of the UPR was persistently enhanced. Furthermore, detailed analysis following the time course showed that MeHg-induced apoptosis is strongly associated with alterations in UPR signaling. Our results suggest that UPR modulation could be a therapeutic target for treating neuropathy.
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Pan J, Li X, Liu H, Wang C, Xu S, Xu B, Deng Y, Yang T, Liu W. Exploring the molecular mechanisms underlie the endoplasmic reticulum stress-mediated methylmercury-induced neuronal developmental damage. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2022; 245:114099. [PMID: 36152427 DOI: 10.1016/j.ecoenv.2022.114099] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Revised: 09/01/2022] [Accepted: 09/16/2022] [Indexed: 06/16/2023]
Abstract
Methylmercury (MeHg) is a ubiquitous environmental pollutant, which can cross the placenta and blood brain barrier, thus affecting fetal growth and development. Although previous studies have demonstrated that MeHg induces endoplasmic reticulum (ER) stress in rat cerebral cortex and primary neurons, the role of ER stress in MeHg-induced neurodevelopmental toxicity remains unclear. Here, we used ICR pregnant mice and hippocampal neurons cells (HT22 cells) to investigate the molecular mechanism by which MeHg exposure during pregnancy affects neurodevelopment. We found that prenatal MeHg exposure caused developmental delay in offspring, accompanied with ER stress, cell apoptosis, cell cycle arrest and abnormal DNA methylation. Then, we used ER stress specific inhibitor 4-PBA and CHOP siRNA to investigate the role of ER stress on HT22 cells damage caused by MeHg. The results showed that 4-PBA pretreatment restored MeHg-induced axonal shortening and alleviated apoptosis, cell cycle arrest and DNA methylation. At the same time, the activation of CHOP/c-Jun/GADD45A signaling pathway was inhibited, and the interaction between CHOP and c-Jun was weakened. In addition, CHOP siRNA reduced the expression of c-Jun and GADD45A, and relieved DNA methylation levels to some extent. In summary, our study suggested that ER stress induced by MeHg mediated cell apoptosis and cell cycle arrest, and may affect DNA methylation through activation of CHOP/c-Jun/GADD45A signaling pathway, thus leading to neuronal damage.
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Affiliation(s)
- Jingjing Pan
- Department of Environmental Health, School of Public Health, China Medical University, China
| | - Xiaoyang Li
- Department of Environmental Health, School of Public Health, China Medical University, China
| | - Haihui Liu
- Department of Environmental Health, School of Public Health, China Medical University, China
| | - Chen Wang
- Department of Environmental Health, School of Public Health, China Medical University, China
| | - Si Xu
- Department of Environmental Health, School of Public Health, China Medical University, China
| | - Bin Xu
- Department of Environmental Health, School of Public Health, China Medical University, China
| | - Yu Deng
- Department of Environmental Health, School of Public Health, China Medical University, China
| | - Tianyao Yang
- Department of Environmental Health, School of Public Health, China Medical University, China
| | - Wei Liu
- Department of Environmental Health, School of Public Health, China Medical University, China.
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12
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Fujimura M, Usuki F. Cellular Conditions Responsible for Methylmercury-Mediated Neurotoxicity. Int J Mol Sci 2022; 23:ijms23137218. [PMID: 35806222 PMCID: PMC9266708 DOI: 10.3390/ijms23137218] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 06/25/2022] [Accepted: 06/27/2022] [Indexed: 12/10/2022] Open
Abstract
Methylmercury (MeHg) is a widely known environmental pollutant that causes severe neurotoxicity. MeHg-induced neurotoxicity depends on various cellular conditions, including differences in the characteristics of tissues and cells, exposure age (fetal, childhood, or adulthood), and exposure levels. Research has highlighted the importance of oxidative stress in the pathogenesis of MeHg-induced toxicity and the site- and cell-specific nature of MeHg-induced neurotoxicity. The cerebellar granule cells and deeper layer cerebrocortical neurons are vulnerable to MeHg. In contrast, the hippocampal neurons are resistant to MeHg, even at high mercury accumulation levels. This review summarizes the mechanisms underlying MeHg-mediated intracellular events that lead to site-specific neurotoxicity. Specifically, we discuss the mechanisms associated with the redox ability, neural outgrowth and synapse formation, cellular signaling pathways, epigenetics, and the inflammatory conditions of microglia.
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Affiliation(s)
- Masatake Fujimura
- Department of Basic Medical Sciences, National Institute for Minamata Disease, Kumamoto 867-0008, Japan
- Correspondence: ; Tel.: +81-966-63-3111; Fax: +81-966-61-1145
| | - Fusako Usuki
- Division of Neuroimmunology, Joint Research Center for Human Retrovirus Infection, Kagoshima University, Kagoshima 890-8544, Japan;
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13
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Pan J, Wei Y, Ni L, Li X, Deng Y, Xu B, Yang T, Sun J, Liu W. Unbalanced ER-mitochondrial calcium homeostasis promotes mitochondrial dysfunction and associated apoptotic pathways activation in methylmercury exposed rat cortical neurons. J Biochem Mol Toxicol 2022; 36:e23136. [PMID: 35678294 DOI: 10.1002/jbt.23136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 04/05/2022] [Accepted: 05/30/2022] [Indexed: 11/06/2022]
Abstract
Methylmercury (MeHg) is a cumulative environmental pollutant that can easily cross the blood-brain barrier and cause damage to the brain, mainly targeting the central nervous system. The purpose of this study is to investigate the role of calcium ion (Ca2+ ) homeostasis between the endoplasmic reticulum (ER) and mitochondria in MeHg-induced neurotoxicity. Rat primary cortical neurons exposed to MeHg (0.25-1 μm) underwent dose-dependent cell damage, accompanied by increased Ca2+ release from the ER and elevated levels of free Ca2+ in cytoplasm and mitochondria. MeHg also increased the protein and messenger RNA expressions of the inositol 1,4,5-triphosphate receptor, ryanodine receptor 2, and mitochondrial calcium uniporter. Ca2+ channel inhibitors 2-aminoethyl diphenylborinate and procaine reduced the release of Ca2+ from ER, while RR and 4,4'-diisothiocyanatostilbene-2,2'-disulfonate inhibited Ca2+ uptake from mitochondria. In addition, pretreatment with Ca2+ chelator BAPTA-AM effectively restored mitochondrial membrane potential levels, inhibited over opening of mitochondrial permeability transition pore, and maintained mitochondrial function stability. Meanwhile, the expression of mitochondrial apoptosis-related proteins recovered to some extent, along with the reduction of the early apoptosis ratio. These results suggest that Ca2+ homeostasis plays an essential role in mitochondrial damage and apoptosis induced by MeHg, which may be one of the important mechanisms of MeHg-induced neurotoxicity.
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Affiliation(s)
- Jingjing Pan
- Department of Environmental Health, School of Public Health, China Medical University, Shenyang, Liaoning, P. R. China
| | - Yanfeng Wei
- Department of Environmental Health, School of Public Health, China Medical University, Shenyang, Liaoning, P. R. China
| | - Linlin Ni
- Department of Environmental Health, School of Public Health, China Medical University, Shenyang, Liaoning, P. R. China
| | - Xiaoyang Li
- Department of Environmental Health, School of Public Health, China Medical University, Shenyang, Liaoning, P. R. China
| | - Yu Deng
- Department of Environmental Health, School of Public Health, China Medical University, Shenyang, Liaoning, P. R. China
| | - Bin Xu
- Department of Environmental Health, School of Public Health, China Medical University, Shenyang, Liaoning, P. R. China
| | - Tianyao Yang
- Department of Environmental Health, School of Public Health, China Medical University, Shenyang, Liaoning, P. R. China
| | - Jingyi Sun
- Department of Cardiology, The Second Hospital of Dalian Medical University, Dalian, Liaoning, P. R. China
| | - Wei Liu
- Department of Environmental Health, School of Public Health, China Medical University, Shenyang, Liaoning, P. R. China
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14
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Huang CH, Wang FT, Chan WH. Low-dose silver nanoparticles plus methyl mercury exert embryotoxic effects on mouse blastocysts via endoplasmic reticulum stress and mitochondrial apoptosis. Toxicol Res (Camb) 2022; 11:460-474. [PMID: 35782646 PMCID: PMC9244727 DOI: 10.1093/toxres/tfac028] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 04/29/2022] [Accepted: 05/02/2022] [Indexed: 07/30/2023] Open
Abstract
The health and environmental impacts of the increasing commercial use of silver nanoparticles (AgNPs) are a growing concern. Methyl mercury (MeHg) is a potent toxin that biotransforms from mercury or inorganic mercury compounds in waterways and causes dangerous environmental contamination. However, the potential interactions and combined effects of AgNPs and MeHg are yet to be established. In the current study, we showed that low/non-embryotoxic doses of AgNPs and MeHg interact synergistically to induce embryotoxicity and further explored the underlying mechanisms affecting mouse embryo development. Notably, co-treatment with noncytotoxic concentrations of AgNPs (10 μM) and MeHg (0.1 μM) triggered apoptotic processes and embryotoxicity in mouse blastocysts and evoked intracellular reactive oxygen species (ROS) generation, which was effectively blocked by preincubation with 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (trolox), a classic antioxidant. Further experiments demonstrated that ROS serve as a key upstream inducer of endoplasmic reticulum (ER) stress and mitochondria-dependent apoptotic processes in AgNP/MeHg-induced injury of mouse embryo implantation and pre- and postimplantation development. Our results collectively indicate that AgNP and MeHg at non-embryotoxic concentrations can synergistically evoke ROS, ultimately causing embryotoxicity through promotion of ER stress and mitochondria-dependent apoptotic signaling cascades.
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Affiliation(s)
- Chien-Hsun Huang
- Department of Obstetrics and Gynecology, Taoyuan General Hospital, Ministry of Health & Welfare, Zhongshan Road, Taoyuan District, Taoyuan City 33004, Taiwan
| | - Fu-Ting Wang
- Rehabilitation and Technical Aid Center, Taipei Veterans General Hospital, Section 2, Shipai Road, Beitou District, Taipei City 11217, Taiwan
| | - Wen-Hsiung Chan
- Corresponding author: Department of Bioscience Technology and Center for Nanotechnology, Chung Yuan Christian University, Zhongbei Road, Zhongli District, Taoyuan City 32023, Taiwan.
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15
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Norketamine, the Main Metabolite of Ketamine, Induces Mitochondria-Dependent and ER Stress-Triggered Apoptotic Death in Urothelial Cells via a Ca2+-Regulated ERK1/2-Activating Pathway. Int J Mol Sci 2022; 23:ijms23094666. [PMID: 35563057 PMCID: PMC9102902 DOI: 10.3390/ijms23094666] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Revised: 04/17/2022] [Accepted: 04/20/2022] [Indexed: 02/01/2023] Open
Abstract
Ketamine-associated cystitis is characterized by suburothelial inflammation and urothelial cell death. Norketamine (NK), the main metabolite of ketamine, is abundant in urine following ketamine exposure. NK has been speculated to exert toxic effects in urothelial cells, similarly to ketamine. However, the molecular mechanisms contributing to NK-induced urothelial cytotoxicity are almost unclear. Here, we aimed to investigate the toxic effects of NK and the potential mechanisms underlying NK-induced urothelial cell injury. In this study, NK exposure significantly reduced cell viability and induced apoptosis in human urinary bladder epithelial-derived RT4 cells that NK (0.01–0.5 mM) exhibited greater cytotoxicity than ketamine (0.1–3 mM). Signals of mitochondrial dysfunction, including mitochondrial membrane potential (MMP) loss and cytosolic cytochrome c release, were found to be involved in NK-induced cell apoptosis and death. NK exposure of cells also triggered the expression of endoplasmic reticulum (ER) stress-related proteins including GRP78, CHOP, XBP-1, ATF-4 and -6, caspase-12, PERK, eIF-2α, and IRE-1. Pretreatment with 4-phenylbutyric acid (an ER stress inhibitor) markedly prevented the expression of ER stress-related proteins and apoptotic events in NK-exposed cells. Additionally, NK exposure significantly activated JNK, ERK1/2, and p38 signaling and increased intracellular calcium concentrations ([Ca2+]i). Pretreatment of cells with both PD98059 (an ERK1/2 inhibitor) and BAPTA/AM (a cell-permeable Ca2+ chelator), but not SP600125 (a JNK inhibitor) and SB203580 (a p38 inhibitor), effectively suppressed NK-induced mitochondrial dysfunction, ER stress-related signals, and apoptotic events. The elevation of [Ca2+]i in NK-exposed cells could be obviously inhibited by BAPTA/AM, but not PD98059. Taken together, these findings suggest that NK exposure exerts urothelial cytotoxicity via a [Ca2+]i-regulated ERK1/2 activation, which is involved in downstream mediation of the mitochondria-dependent and ER stress-triggered apoptotic pathway, consequently resulting in urothelial cell death. Our findings suggest that regulating [Ca2+]i/ERK signaling pathways may be a promising strategy for treatment of NK-induced urothelial cystitis.
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16
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Takanezawa Y, Harada R, Shibagaki Y, Kashiwano Y, Nakamura R, Ohshiro Y, Uraguchi S, Kiyono M. Protective function of the SQSTM1/p62-NEDD4 complex against methylmercury toxicity. Biochem Biophys Res Commun 2022; 609:134-140. [PMID: 35452957 DOI: 10.1016/j.bbrc.2022.04.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Accepted: 04/06/2022] [Indexed: 11/02/2022]
Abstract
SQSTM1/p62, hereinafter referred to as p62, is a stress-induced cellular protein that interacts with various signaling proteins as well as ubiquitinated proteins to regulate a variety of cellular functions and cell survival. Methylmercury (MeHg) exposure increases the levels of p62, the latter playing a protective role in MeHg-induced toxicity. However, the underlying mechanism by which p62 alleviates MeHg toxicity remains poorly understood. Herein, we report the interaction of p62 with neural precursor cell expressed developmentally down-regulated protein 4 (NEDD4), a HECT E3 ubiquitin ligase. The region of p62 where NEDD4 binds is located at the proline- and arginine (PR)-rich region (amino acids: 102-119), C-terminal extension of the Phox and Bem1 (PB1) domain. To evaluate the importance of the p62-NEDD4 complex, we examined the compensation of deletion mutant (GFP-Δ102-119 p62) for the lack of endogenous p62 in MEFs. GFP-p62/p62KO cells exhibited significantly higher cell viability than GFP-Δ102-119 p62/p62KO cells after treatment with MeHg. Our findings suggest novel mechanisms to alleviate MeHg toxicity through p62-NEDD4 complex formation.
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Affiliation(s)
- Yasukazu Takanezawa
- Department of Public Health, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo, 108-8641, Japan.
| | - Ryohei Harada
- Department of Public Health, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo, 108-8641, Japan
| | - Yoshio Shibagaki
- Division of Biochemistry, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo, 108-8641, Japan
| | - Yui Kashiwano
- Department of Public Health, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo, 108-8641, Japan
| | - Ryosuke Nakamura
- Department of Public Health, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo, 108-8641, Japan
| | - Yuka Ohshiro
- Department of Public Health, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo, 108-8641, Japan
| | - Shimpei Uraguchi
- Department of Public Health, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo, 108-8641, Japan
| | - Masako Kiyono
- Department of Public Health, School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo, 108-8641, Japan
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17
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Hu Q, Zheng J, Xu XN, Gu C, Li W. Uranium induces kidney cells apoptosis via reactive oxygen species generation, endoplasmic reticulum stress and inhibition of PI3K/AKT/mTOR signaling in culture. ENVIRONMENTAL TOXICOLOGY 2022; 37:899-909. [PMID: 35044038 DOI: 10.1002/tox.23453] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 12/21/2021] [Accepted: 12/27/2021] [Indexed: 05/20/2023]
Abstract
Uranium (U) induces generation of excessive intracellular reactive oxygen species (ROS), which is generally considered as a possible mediator of U-triggered kidney tubular cells injury and nephrotoxicity. Our goal is designed to elucidate that the precise molecular mechanism in ROS downstream is association with U-induced NRK-52E cells apoptosis. The results show that U intoxication in NRK-52E cells reduced cell activity and triggered apoptosis, as demonstrated by flow cytometry and apoptotic marker cleaved Caspase-3 expression. U exposure triggered endoplasmic reticulum (ER) stress, which is involvement of apoptosis determined by marker molecules including GRP78, PERK, IRE1, ATF6, CHOP, cleaved Caspase-12, and Caspase-3. Administration of antioxidant N-acetylcysteine (NAC) effectively blocked U-triggered ROS generation, ER stress, and apoptosis. U contamination evidently decreased the expression of phosphorylation PI3K, AKT, and mTOR and ratios of their respective phosphorylation to the corresponding total proteins. Application of a PI3K activator IGF-1 significantly abolished these adverse effects of U intoxication on PI3K/AKT/mTOR signaling and subsequently abrogated U-triggered apoptosis. NAC also effectively reversed down-regulation of phosphorylated PI3K induced by U exposure. Taken together, these data strongly suggest that U treatment induces NRK-52E cells apoptosis through ROS production, ER stress, and down-regulation of PI3K/AKT/mTOR signaling. Targeting ROS formation-, ER stress-, and PI3K/AKT/mTOR pathway-mediated apoptosis could be a novel approach for attenuating U-triggered nephrotoxicity.
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Affiliation(s)
- Qiaoni Hu
- Department of Health Inspection and Quarantine, School of Public Health, Guilin Medical University, Guilin, China
| | - Jifang Zheng
- Department of Health Inspection and Quarantine, School of Public Health, Guilin Medical University, Guilin, China
- Guangxi Key Laboratory of Tumor Immunology and Microenvironment Regulation, Faculty of Basic Medical Sciences, Guilin Medical University, Guilin, China
| | - Xiao Na Xu
- Department of Health Inspection and Quarantine, School of Public Health, Guilin Medical University, Guilin, China
| | - Chaohao Gu
- Guangxi Key Laboratory of Tumor Immunology and Microenvironment Regulation, Faculty of Basic Medical Sciences, Guilin Medical University, Guilin, China
| | - Wanting Li
- Guangxi Key Laboratory of Tumor Immunology and Microenvironment Regulation, Faculty of Basic Medical Sciences, Guilin Medical University, Guilin, China
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18
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Yang CY, Liu SH, Su CC, Fang KM, Yang TY, Liu JM, Chen YW, Chang KC, Chuang HL, Wu CT, Lee KI, Huang CF. Methylmercury Induces Mitochondria- and Endoplasmic Reticulum Stress-Dependent Pancreatic β-Cell Apoptosis via an Oxidative Stress-Mediated JNK Signaling Pathway. Int J Mol Sci 2022; 23:ijms23052858. [PMID: 35270009 PMCID: PMC8910963 DOI: 10.3390/ijms23052858] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 02/21/2022] [Accepted: 03/01/2022] [Indexed: 12/21/2022] Open
Abstract
Methylmercury (MeHg), a long-lasting organic pollutant, is known to induce cytotoxic effects in mammalian cells. Epidemiological studies have suggested that environmental exposure to MeHg is linked to the development of diabetes mellitus (DM). The exact molecular mechanism of MeHg-induced pancreatic β-cell cytotoxicity is still unclear. Here, we found that MeHg (1-4 μM) significantly decreased insulin secretion and cell viability in pancreatic β-cell-derived RIN-m5F cells. A concomitant elevation of mitochondrial-dependent apoptotic events was observed, including decreased mitochondrial membrane potential and increased proapoptotic (Bax, Bak, p53)/antiapoptotic (Bcl-2) mRNA ratio, cytochrome c release, annexin V-Cy3 binding, caspase-3 activity, and caspase-3/-7/-9 activation. Exposure of RIN-m5F cells to MeHg (2 μM) also induced protein expression of endoplasmic reticulum (ER) stress-related signaling molecules, including C/EBP homologous protein (CHOP), X-box binding protein (XBP-1), and caspase-12. Pretreatment with 4-phenylbutyric acid (4-PBA; an ER stress inhibitor) and specific siRNAs for CHOP and XBP-1 significantly inhibited their expression and caspase-3/-12 activation in MeHg-exposed RIN-mF cells. MeHg could also evoke c-Jun N-terminal kinase (JNK) activation and reactive oxygen species (ROS) generation. Antioxidant N-acetylcysteine (NAC; 1mM) or 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (trolox; 100 μM) markedly prevented MeH-induced ROS generation and decreased cell viability in RIN-m5F cells. Furthermore, pretreatment of cells with SP600125 (JNK inhibitor; 10 μM) or NAC (1 mM) or transfection with JNK-specific siRNA obviously attenuated the MeHg-induced JNK phosphorylation, CHOP and XBP-1 protein expression, apoptotic events, and insulin secretion dysfunction. NAC significantly inhibited MeHg-activated JNK signaling, but SP600125 could not effectively reduce MeHg-induced ROS generation. Collectively, these findings demonstrate that the induction of ROS-activated JNK signaling is a crucial mechanism underlying MeHg-induced mitochondria- and ER stress-dependent apoptosis, ultimately leading to β-cell death.
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Affiliation(s)
- Ching-Yao Yang
- Department of Surgery, National Taiwan University Hospital, Taipei 100, Taiwan;
- Department of Surgery, College of Medicine, National Taiwan University, Taipei 100, Taiwan
| | - Shing-Hwa Liu
- Institute of Toxicology, College of Medicine, National Taiwan University, Taipei 100, Taiwan;
| | - Chin-Chuan Su
- Department of Otorhinolaryngology, Head and Neck Surgery, Changhua Christian Hospital, Changhua County 500, Taiwan;
| | - Kai-Min Fang
- Department of Otolaryngology, Far Eastern Memorial Hospital, New Taipei City 220, Taiwan;
| | - Tsung-Yuan Yang
- Department of Internal Medicine, Chung Shan Medical University Hospital, Taichung 402, Taiwan;
- School of Medicine, Institute of Medicine, Chung-Shan Medical University, Taichung 402, Taiwan
| | - Jui-Ming Liu
- Department of Urology, Taoyuan General Hospital, Ministry of Health and Welfare, Taoyuan 330, Taiwan;
- Department of Obstetrics and Gynecology, Tri-Service General Hospital, National Defense Medical Center, Taipei 114, Taiwan
| | - Ya-Wen Chen
- Department of Physiology, School of Medicine, College of Medicine, China Medical University, Taichung 404, Taiwan;
| | - Kai-Chih Chang
- Center for Digestive Medicine, Department of Internal Medicine, China Medical University Hospital, Taichung 404, Taiwan;
| | - Haw-Ling Chuang
- Department of Emergency, Taichung Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Taichung 427, Taiwan;
| | - Cheng-Tien Wu
- Department of Nutrition and Master Program of Food and Drug Safety, China Medical University, Taichung 40402, Taiwan;
| | - Kuan-I Lee
- Department of Emergency, Taichung Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Taichung 427, Taiwan;
- Correspondence: (K.-I.L.); (C.-F.H.)
| | - Chun-Fa Huang
- School of Chinese Medicine, College of Chinese Medicine, China Medical University, Taichung 404, Taiwan
- Department of Nursing, College of Medical and Health Science, Asia University, Taichung 413, Taiwan
- Correspondence: (K.-I.L.); (C.-F.H.)
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19
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Ni L, Wei Y, Pan J, Li X, Xu B, Deng Y, Yang T, Liu W. Shedding New Light on Methylmercury-induced Neurotoxicity Through the Crosstalk Between Autophagy and Apoptosis. Toxicol Lett 2022; 359:55-64. [PMID: 35122893 DOI: 10.1016/j.toxlet.2022.01.020] [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: 07/12/2021] [Revised: 11/23/2021] [Accepted: 01/29/2022] [Indexed: 02/06/2023]
Abstract
Methylmercury (MeHg) is a bio-accumulative global environmental contaminant present in fish and seafood. MeHg accumulates in the aquatic environment and eventually reaches the human system via the food chain by bio-magnification. The central nervous system is the primary target of toxicity and is particularly vulnerable during development. It is well documented that developmental MeHg exposure can lead to neurological alterations, including cognitive and motor dysfunction. Apoptosis is a primary characteristic of MeHg-induced neurotoxicity, and may be regulated by autophagic activity. However, mechanisms mediating the interaction between apoptosis and autophagy remains to be explored. Autophagy is an adaptive response under stressful conditions, and the basal level of autophagy ensures the physiological turnover of old and damaged organelles. Autophagy can regulate cell fate through different crosstalk signaling pathways. A complex interplay between autophagy and apoptosis determines the degree of apoptosis and the progression of MeHg-induced neurotoxicity as demonstrated by pre-clinical models and clinical trials. This review summarizes recent advances in the roles of autophagy and apoptosis in MeHg neurotoxicity and thoroughly explores the relationship between them. The autophagic pathway may be a potential therapeutic target in MeHg neurotoxicity through modulation of apoptosis.
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Affiliation(s)
- Linlin Ni
- Department of Environmental Health, School of Public Health, China Medical University, No. 77 Puhe Road, Shenyang North New Area, Shenyang 110122, Liaoning, People's Republic of China
| | - Yanfeng Wei
- Department of Environmental Health, School of Public Health, China Medical University, No. 77 Puhe Road, Shenyang North New Area, Shenyang 110122, Liaoning, People's Republic of China
| | - Jingjing Pan
- Department of Environmental Health, School of Public Health, China Medical University, No. 77 Puhe Road, Shenyang North New Area, Shenyang 110122, Liaoning, People's Republic of China
| | - Xiaoyang Li
- Department of Environmental Health, School of Public Health, China Medical University, No. 77 Puhe Road, Shenyang North New Area, Shenyang 110122, Liaoning, People's Republic of China
| | - Bin Xu
- Department of Environmental Health, School of Public Health, China Medical University, No. 77 Puhe Road, Shenyang North New Area, Shenyang 110122, Liaoning, People's Republic of China
| | - Yu Deng
- Department of Environmental Health, School of Public Health, China Medical University, No. 77 Puhe Road, Shenyang North New Area, Shenyang 110122, Liaoning, People's Republic of China
| | - Tianyao Yang
- Department of Environmental Health, School of Public Health, China Medical University, No. 77 Puhe Road, Shenyang North New Area, Shenyang 110122, Liaoning, People's Republic of China
| | - Wei Liu
- Department of Environmental Health, School of Public Health, China Medical University, No. 77 Puhe Road, Shenyang North New Area, Shenyang 110122, Liaoning, People's Republic of China.
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20
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Methylmercury exposure during prenatal and postnatal neurodevelopment promotes oxidative stress associated with motor and cognitive damages in rats: an environmental-experimental toxicology study. Toxicol Rep 2022; 9:563-574. [PMID: 35392159 PMCID: PMC8980556 DOI: 10.1016/j.toxrep.2022.02.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Revised: 01/29/2022] [Accepted: 02/25/2022] [Indexed: 12/11/2022] Open
Abstract
The environmental contamination by methylmercury (MeHg) is a major concern for public health. The effects of MeHg in the central nervous system (CNS) of adult animals have been extensively investigated; however, little is known about the effects of MeHg exposure during intrauterine and lactation periods on motor and cognitive functions of adolescent rats. Therefore, this study aimed to investigate the effect of MeHg exposure during intrauterine life and lactation on both motor and cognitive functions of offspring rats. Ten female Wistar rats were exposed to 40 μg/kg/day of MeHg through cookie treats from the first day of pregnancy until the last day of breastfeeding. Both motor and cognitive functions of offspring male rats were assessed by open field, rotarod, and step-down inhibitory avoidance tests. Forty-one days after birth, the hippocampus and cerebellum were collected to determine total Hg content, antioxidant capacity against peroxyl radicals (ACAP), reduced glutathione (GSH) levels, lipid peroxidation (LPO), and nitrite levels. MeHg exposure during CNS development increased Hg levels in both hippocampal and cerebellar parenchymas, triggered oxidative stress throughout ACAP and GSH decrease, increased LPO and nitrite levels. These alterations resulted in reduced spontaneous and stimulated locomotion and short- and long-term memory deficits. Therefore, damages triggered by MeHg exposure during intrauterine life and lactation had detrimental effects on oxidative biochemistry and motor and cognitive functions of offspring rats. The MeHg exposure during CNS development increased mercury levels in hippocampal and cerebellar parenchyma. The MeHg intoxication during pregnancy and lactation impairs the redox status of hippocampus and cerebellum of the offspring. MeHg exposure causes behavioral effects in motor ability and cognition of offspring rats.
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21
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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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22
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p62/sequestosome 1 attenuates methylmercury-induced endoplasmic reticulum stress in mouse embryonic fibroblasts. Toxicol Lett 2021; 353:93-99. [PMID: 34678407 DOI: 10.1016/j.toxlet.2021.10.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2021] [Revised: 09/29/2021] [Accepted: 10/14/2021] [Indexed: 01/07/2023]
Abstract
Methylmercury (MeHg) is a hazardous environmental pollutant that causes serious toxicity in humans and animals, as well as proteotoxic stress. In our previous study, we found that MeHg induces the expression of p62/sequestosome 1 (p62) that selectively targets ubiquitinated proteins for degradation via autophagy, and that p62 might protect cells against MeHg toxicity. To further investigate the role of p62 in MeHg-induced stress responses, we evaluated the role of p62 in MeHg-induced endoplasmic reticulum (ER) stress in p62 knockout (p62KO) mouse embryonic fibroblasts (MEFs). Treatment of wild-type (WT) MEFs were treated with MeHg (1 μM) increased mRNA levels of Chop encoding C/EBP homologous protein, Trib3 encoding Tribbles homolog 3, and Dnajb9 encoding DnaJ heat-shock protein family (Hsp40) member B9 increased, suggesting that ER stress is elicited by MeHg stress. Additionally, p62KO MEFs treated with MeHg showed a higher mRNA expression of Chop and Trib3 relative to that in WT MEFs. Furthermore, knock-in of GFP-p62 to p62KO cells diminished the Chop and Trib3 induction responses to MeHg stress and resulted in a higher cell viability than that of p62KO MEFs. These results suggest that the protective role of p62 against MeHg toxicity is partly mediated by suppressing the ER stress response.
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23
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de Oliveira Lopes G, Aragão WAB, Bittencourt LO, Puty B, Lopes AP, Dos Santos SM, Monteiro MC, de Oliveira EHC, da Silva MCF, Lima RR. Imaging Microstructural Damage and Alveolar Bone Loss in Rats Systemically Exposed to Methylmercury: First Experimental Evidence. Biol Trace Elem Res 2021; 199:3707-3717. [PMID: 33409908 DOI: 10.1007/s12011-020-02492-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Accepted: 11/12/2020] [Indexed: 10/22/2022]
Abstract
The alveolar bone is an important mineralized structure of the periodontal support apparatus, and information about the methylmercury (MeHg) effects on the structural integrity is scarce. Therefore, this study aimed to investigate whether systemic, chronic, and low-dose exposure to MeHg can change the alveolar bone microstructure of rats. Adult Wistar rats (n = 30) were exposed to 0.04 mg/kg/day of MeHg or vehicle through intragastric gavage. The animals were euthanized after 60 days, and blood samples were collected for trolox equivalent antioxidant capacity (TEAC), glutathione (GSH), lipid peroxidation (LPO), and comet assays. The mandible of each animal was collected and separated into hemimandibles that were used to determine the total Hg level in the bone and to analyze microstructural damage and alveolar bone loss in terms of trabecular number (Tb.N), trabecular thickness (Tb.Th), bone volume fraction (BV/TV), and exposed root area of the second molars. MeHg exposure triggered oxidative stress in blood represented by lower levels of GSH and TEAC and the increase in LPO and DNA damage of the blood cells. High total Hg levels were found in the alveolar bone, and the microstructural analyses showed a reduction in Tb.N, Tb.Th, and BV/TV, which resulted in an increase in the exposed root area and a decrease in bone height. Long-term MeHg exposure promotes a systemic redox imbalance associated with microstructural changes and alveolar bone loss and may indicate a potential risk indicator for periodontal diseases.
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Affiliation(s)
- Géssica de Oliveira Lopes
- Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Pará, Augusto Corrêa Street N. 01, Guamá, Belém, Pará, 66075-110, Brazil
| | - Walessa Alana Bragança Aragão
- Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Pará, Augusto Corrêa Street N. 01, Guamá, Belém, Pará, 66075-110, Brazil
| | - Leonardo Oliveira Bittencourt
- Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Pará, Augusto Corrêa Street N. 01, Guamá, Belém, Pará, 66075-110, Brazil
| | - Bruna Puty
- Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Pará, Augusto Corrêa Street N. 01, Guamá, Belém, Pará, 66075-110, Brazil
| | - Armando Pereira Lopes
- School of Dentistry, Institute of Health Sciences, Federal University of Pará, Belém, Brazil
| | - Sávio Monteiro Dos Santos
- Laboratory of Clinical Immunology and Oxidative Stress, Pharmacy Faculty, Institute of Health Sciences, Federal University of Pará, Belém, Brazil
| | - Marta Chagas Monteiro
- Laboratory of Clinical Immunology and Oxidative Stress, Pharmacy Faculty, Institute of Health Sciences, Federal University of Pará, Belém, Brazil
| | - Edivaldo Herculano Corrêa de Oliveira
- Cytogenetics and Tissue Culture Laboratory, Evandro Chagas Institute, Ananindeua, Brazil
- Exact and Natural Sciences Institute, Federal University of Pará, Belém, Brazil
| | - Márcia Cristina Freitas da Silva
- Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Pará, Augusto Corrêa Street N. 01, Guamá, Belém, Pará, 66075-110, Brazil
| | - Rafael Rodrigues Lima
- Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Pará, Augusto Corrêa Street N. 01, Guamá, Belém, Pará, 66075-110, Brazil.
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24
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Olsvik PA, Azad AM, Yadetie F. Bioaccumulation of mercury and transcriptional responses in tusk (Brosme brosme), a deep-water fish from a Norwegian fjord. CHEMOSPHERE 2021; 279:130588. [PMID: 33901891 DOI: 10.1016/j.chemosphere.2021.130588] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2021] [Revised: 04/08/2021] [Accepted: 04/12/2021] [Indexed: 06/12/2023]
Abstract
High concentrations of mercury (Hg) have been documented in deep-water fish species from some Norwegian fjords. In this study, tusk (Brosme brosme) was sampled from four locations in the innermost parts of Sognefjorden in Western Norway. Total Hg and methylmercury (MeHg) levels were measured in liver tissue. To search for potential sublethal effects of Hg, we characterized the hepatic transcriptome in tusk with high and low levels of Hg bioaccumulation using global transcriptomics analysis (RNA-seq). The results showed that there was a significant correlation between fish weight and accumulated concentrations of MeHg but not total Hg. MeHg accounted for 30-40% of total Hg in liver of most of the fish, although at concentrations above 2-3 mg Hg/kg wet weight the percentage of MeHg dropped considerably. Transcriptome analysis resulted in hundreds of differentially expressed genes in the liver of tusk with high Hg levels. Functional enrichment analysis suggested that the top affected pathways are associated with protein folding, adipogenesis, notch signaling, and lipid metabolism (beta-oxidation and phospholipids). Based on transcriptional responses pointing to well-known effects of Hg compounds in fish, the study suggests that tusk in Sognefjorden could be negatively impacted by Hg bioaccumulation.
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Affiliation(s)
- Pål A Olsvik
- Faculty of Biosciences and Aquaculture, Nord University, Bodø, Norway; Institute of Marine Research, Nordnes, Bergen, Norway.
| | - Atabak M Azad
- Institute of Marine Research, Nordnes, Bergen, Norway
| | - Fekadu Yadetie
- Department of Biological Sciences, University of Bergen, Bergen, Norway
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Ni L, Wei Y, Pan J, Li X, Xu B, Deng Y, Yang T, Liu W. The effects of mTOR or Vps34-mediated autophagy on methylmercury-induced neuronal apoptosis in rat cerebral cortex. Food Chem Toxicol 2021; 155:112386. [PMID: 34242720 DOI: 10.1016/j.fct.2021.112386] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 07/02/2021] [Accepted: 07/03/2021] [Indexed: 01/13/2023]
Abstract
Methylmercury (MeHg) is a environmental contaminant, which can induce neurotoxic effects. So far, the exact molecular mechanisms of autophagy and its effect on apoptosis in MeHg-induced neurotoxicity have not been elucidated. Here, rats were exposed to MeHg (4, 8, or 12 μmol/kg) for 4 weeks to evaluate the dose-effect relationship between MeHg and apoptosis, or autophagy in cerebral cortex. On this basis, rapamycin (Rapa) or 3-methyladenine (3-MA) was administrated to further explore the regulatory mechanisms of autophagy on MeHg-induced neuronal apoptosis. The pathological changes, autophagy or apoptosis levels, expression of autophagic or apoptotic-associated factors such as mTOR, S6K1, 4EBP1, Vps34, Beclin1, p62, LC3, Bcl-2/Bax, caspase, or MAPKs were investigated. Results showed that MeHg dose-dependently induced pathological changes in cerebral cortex, and the levels of autophagy and apoptosis were increased. Furthermore, Rapa pretreatment antagonized MeHg-induced apoptosis, whereas 3-MA further aggravated apoptosis, which were supported by findings that Rapa activated mTOR-mediated autophagy while 3-MA inhibited Vps34-related autophagy, further affect neuronal apoptosis through regulation of apoptotic factors mentioned above. In conclusion, the findings indicated that MeHg dose-dependently induced autophagy or apoptosis, and mTOR or Vps34 may play important roles in mediating autophagy, which further regulated apoptosis through MAPKs or mitochondrial apoptosis pathways.
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Affiliation(s)
- Linlin Ni
- Department of Environmental Health, School of Public Health, China Medical University, No. 77 Puhe Road, Shenyang North New Area, Shenyang, 110122, Liaoning, People's Republic of China
| | - Yanfeng Wei
- Department of Environmental Health, School of Public Health, China Medical University, No. 77 Puhe Road, Shenyang North New Area, Shenyang, 110122, Liaoning, People's Republic of China
| | - Jingjing Pan
- Department of Environmental Health, School of Public Health, China Medical University, No. 77 Puhe Road, Shenyang North New Area, Shenyang, 110122, Liaoning, People's Republic of China
| | - Xiaoyang Li
- Department of Environmental Health, School of Public Health, China Medical University, No. 77 Puhe Road, Shenyang North New Area, Shenyang, 110122, Liaoning, People's Republic of China
| | - Bin Xu
- Department of Environmental Health, School of Public Health, China Medical University, No. 77 Puhe Road, Shenyang North New Area, Shenyang, 110122, Liaoning, People's Republic of China
| | - Yu Deng
- Department of Environmental Health, School of Public Health, China Medical University, No. 77 Puhe Road, Shenyang North New Area, Shenyang, 110122, Liaoning, People's Republic of China
| | - Tianyao Yang
- Department of Environmental Health, School of Public Health, China Medical University, No. 77 Puhe Road, Shenyang North New Area, Shenyang, 110122, Liaoning, People's Republic of China
| | - Wei Liu
- Department of Environmental Health, School of Public Health, China Medical University, No. 77 Puhe Road, Shenyang North New Area, Shenyang, 110122, Liaoning, People's Republic of China.
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Cheng H, Yang B, Ke T, Li S, Yang X, Aschner M, Chen P. Mechanisms of Metal-Induced Mitochondrial Dysfunction in Neurological Disorders. TOXICS 2021; 9:142. [PMID: 34204190 PMCID: PMC8235163 DOI: 10.3390/toxics9060142] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Revised: 06/12/2021] [Accepted: 06/14/2021] [Indexed: 01/31/2023]
Abstract
Metals are actively involved in multiple catalytic physiological activities. However, metal overload may result in neurotoxicity as it increases formation of reactive oxygen species (ROS) and elevates oxidative stress in the nervous system. Mitochondria are a key target of metal-induced toxicity, given their role in energy production. As the brain consumes a large amount of energy, mitochondrial dysfunction and the subsequent decrease in levels of ATP may significantly disrupt brain function, resulting in neuronal cell death and ensuing neurological disorders. Here, we address contemporary studies on metal-induced mitochondrial dysfunction and its impact on the nervous system.
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Affiliation(s)
- Hong Cheng
- Department of Occupational Health and Environmental Health, School of Public Health, Guangxi Medical University, Nanning 530021, China; (H.C.); (X.Y.)
| | - Bobo Yang
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY 10461, USA; (B.Y.); (T.K.)
| | - Tao Ke
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY 10461, USA; (B.Y.); (T.K.)
| | - Shaojun Li
- Department of Toxicology, School of Public Health, Guangxi Medical University, Nanning 530021, China;
| | - Xiaobo Yang
- Department of Occupational Health and Environmental Health, School of Public Health, Guangxi Medical University, Nanning 530021, China; (H.C.); (X.Y.)
- Department of Public Health, School of Medicine, Guangxi University of Science and Technology, Liuzhou 545006, China
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY 10461, USA; (B.Y.); (T.K.)
| | - Pan Chen
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY 10461, USA; (B.Y.); (T.K.)
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Mechanisms of oxidative stress in methylmercury-induced neurodevelopmental toxicity. Neurotoxicology 2021; 85:33-46. [PMID: 33964343 DOI: 10.1016/j.neuro.2021.05.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 05/02/2021] [Accepted: 05/03/2021] [Indexed: 12/15/2022]
Abstract
Methylmercury (MeHg) is a long-lasting organic environmental pollutant that poses a great threat to human health. Ingestion of seafood containing MeHg is the most important way by which it comes into contact with human body, where the central nervous system (CNS) is the primary target of MeHg toxicity. During periods of pre-plus postnatal, in particular, the brain of offspring is vulnerable to specific developmental insults that result in abnormal neurobehavioral development, even without symptoms in mothers. While many studies on neurotoxic effects of MeHg on the developing brain have been conducted, the mechanisms of oxidative stress in MeHg-induced neurodevelopmental toxicity is less clear. Hitherto, no single process can explain the many effects observed in MeHg-induced neurodevelopmental toxicity. This review summarizes the possible mechanisms of oxidative stress in MeHg-induced neurodevelopmental toxicity, highlighting modulation of Nrf2/Keap1/Notch1, PI3K/AKT, and PKC/MAPK molecular pathways as well as some preventive drugs, and thus contributes to the discovery of endogenous and exogenous molecules that can counteract MeHg-induced neurodevelopmental toxicity.
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Ramadan SS, Almeer RS, Alkahtani S, Alarifi S, Albasher G, Abdel Moneim AE. Ziziphus spina-christi leaf extract attenuates mercuric chloride-induced liver injury in male rats via inhibition of oxidative damage. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2021; 28:17482-17494. [PMID: 33394435 DOI: 10.1007/s11356-020-12160-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Accepted: 12/17/2020] [Indexed: 06/12/2023]
Abstract
Heavy metal contamination including mercury (Hg) has become one of the most serious environmental problems facing humans and other living organisms. Here, the hepatoprotective effects of Z. spina-christi leaf extract (ZCE) against inorganic mercury salt (mercuric chloride; HgCl2)-induced hepatotoxicity model was investigated in rats. Mercury concentration, liver function markers, oxidative stress markers, inflammation, cell death indicators, and histopathology were assessed. ZCE protected against HgCl2-induced hepatotoxicity, decreased Hg concentration, lipid peroxidation, and nitric oxide, increased glutathione, superoxide dismutase, catalase, and glutathione recycling enzymes (peroxidase and reductase), and upregulated nuclear factor-erythroid 2-related factor 2 (Nrf2) gene expression in HgCl2-intoxicated rat hepatic tissue. Nrf2 downstream gene and heme oxygenase-1 were also upregulated, confirming that hepatoprotection by ZCE against HgCl2-induced liver damage involved activation of the Nrf2/antioxidant response element pathway. ZCE also decreased the expression and production of pro-inflammatory cytokines and pro-apoptotic proteins and increased anti-apoptotic protein Bcl-2. Immunohistochemical analysis of liver tissues of HgCl2-treated rats confirmed the alternations of apoptotic-related protein expression. Our data demonstrated that post-administration of ZCE attenuated HgCl2-induced liver damage by activating the Nrf2/HO-1 signaling pathway. Therefore, administering this extract may be a novel therapeutic strategy for inorganic mercury intoxication.
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Affiliation(s)
- Shimaa S Ramadan
- Department of Chemistry, Faculty of Science, Helwan University, Cairo, Egypt
| | - Rafa S Almeer
- Department of Zoology, College of Science, King Saud University, Riyadh, Saudi Arabia.
| | - Saad Alkahtani
- Department of Zoology, College of Science, King Saud University, Riyadh, Saudi Arabia
| | - Saud Alarifi
- Department of Zoology, College of Science, King Saud University, Riyadh, Saudi Arabia
| | - Gadah Albasher
- Department of Zoology, College of Science, King Saud University, Riyadh, Saudi Arabia
| | - Ahmed E Abdel Moneim
- Department of Zoology and Entomology, Faculty of Science, Helwan University, Cairo, Egypt
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Novo JP, Martins B, Raposo RS, Pereira FC, Oriá RB, Malva JO, Fontes-Ribeiro C. Cellular and Molecular Mechanisms Mediating Methylmercury Neurotoxicity and Neuroinflammation. Int J Mol Sci 2021; 22:ijms22063101. [PMID: 33803585 PMCID: PMC8003103 DOI: 10.3390/ijms22063101] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2021] [Revised: 03/06/2021] [Accepted: 03/15/2021] [Indexed: 02/06/2023] Open
Abstract
Methylmercury (MeHg) toxicity is a major environmental concern. In the aquatic reservoir, MeHg bioaccumulates along the food chain until it is consumed by riverine populations. There has been much interest in the neurotoxicity of MeHg due to recent environmental disasters. Studies have also addressed the implications of long-term MeHg exposure for humans. The central nervous system is particularly susceptible to the deleterious effects of MeHg, as evidenced by clinical symptoms and histopathological changes in poisoned humans. In vitro and in vivo studies have been crucial in deciphering the molecular mechanisms underlying MeHg-induced neurotoxicity. A collection of cellular and molecular alterations including cytokine release, oxidative stress, mitochondrial dysfunction, Ca2+ and glutamate dyshomeostasis, and cell death mechanisms are important consequences of brain cells exposure to MeHg. The purpose of this review is to organize an overview of the mercury cycle and MeHg poisoning events and to summarize data from cellular, animal, and human studies focusing on MeHg effects in neurons and glial cells. This review proposes an up-to-date compendium that will serve as a starting point for further studies and a consultation reference of published studies.
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Affiliation(s)
- João P. Novo
- Institute for Clinical and Biomedical Research (iCBR), Center for Innovative Biomedicine and Biotechnology (CIBB), and Institute of Pharmacology and Experimental Therapeutics, Faculty of Medicine, University of Coimbra, 3000-548 Coimbra, Portugal; (J.P.N.); (B.M.); (R.S.R.); (F.C.P.)
| | - Beatriz Martins
- Institute for Clinical and Biomedical Research (iCBR), Center for Innovative Biomedicine and Biotechnology (CIBB), and Institute of Pharmacology and Experimental Therapeutics, Faculty of Medicine, University of Coimbra, 3000-548 Coimbra, Portugal; (J.P.N.); (B.M.); (R.S.R.); (F.C.P.)
| | - Ramon S. Raposo
- Institute for Clinical and Biomedical Research (iCBR), Center for Innovative Biomedicine and Biotechnology (CIBB), and Institute of Pharmacology and Experimental Therapeutics, Faculty of Medicine, University of Coimbra, 3000-548 Coimbra, Portugal; (J.P.N.); (B.M.); (R.S.R.); (F.C.P.)
- Experimental Biology Core, University of Fortaleza, Health Sciences, Fortaleza 60110-001, Brazil
| | - Frederico C. Pereira
- Institute for Clinical and Biomedical Research (iCBR), Center for Innovative Biomedicine and Biotechnology (CIBB), and Institute of Pharmacology and Experimental Therapeutics, Faculty of Medicine, University of Coimbra, 3000-548 Coimbra, Portugal; (J.P.N.); (B.M.); (R.S.R.); (F.C.P.)
| | - Reinaldo B. Oriá
- Laboratory of Tissue Healing, Ontogeny and Nutrition, Department of Morphology and Institute of Biomedicine, School of Medicine, Federal University of Ceará, Fortaleza 60430-270, Brazil;
| | - João O. Malva
- Institute for Clinical and Biomedical Research (iCBR), Center for Innovative Biomedicine and Biotechnology (CIBB), and Institute of Pharmacology and Experimental Therapeutics, Faculty of Medicine, University of Coimbra, 3000-548 Coimbra, Portugal; (J.P.N.); (B.M.); (R.S.R.); (F.C.P.)
- Correspondence: (J.O.M.); (C.F.-R.)
| | - Carlos Fontes-Ribeiro
- Institute for Clinical and Biomedical Research (iCBR), Center for Innovative Biomedicine and Biotechnology (CIBB), and Institute of Pharmacology and Experimental Therapeutics, Faculty of Medicine, University of Coimbra, 3000-548 Coimbra, Portugal; (J.P.N.); (B.M.); (R.S.R.); (F.C.P.)
- Correspondence: (J.O.M.); (C.F.-R.)
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30
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Hiraoka H, Nomura R, Takasugi N, Akai R, Iwawaki T, Kumagai Y, Fujimura M, Uehara T. Spatiotemporal analysis of the UPR transition induced by methylmercury in the mouse brain. Arch Toxicol 2021; 95:1241-1250. [PMID: 33454823 DOI: 10.1007/s00204-021-02982-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Accepted: 01/06/2021] [Indexed: 01/11/2023]
Abstract
Methylmercury (MeHg), an environmental toxicant, induces neuronal cell death and injures a specific area of the brain. MeHg-mediated neurotoxicity is believed to be caused by oxidative stress and endoplasmic reticulum (ER) stress but the mechanism by which those stresses lead to neuronal loss is unclear. Here, by utilizing the ER stress-activated indicator (ERAI) system, we investigated the signaling alterations in the unfolded protein response (UPR) prior to neuronal apoptosis in the mouse brain. In ERAI transgenic mice exposed to MeHg (25 mg/kg, S.C.), the ERAI signal, which indicates activation of the cytoprotective pathway of the UPR, was detected in the brain. Interestingly, detailed ex vivo analysis showed that the ERAI signal was localized predominantly in neurons. Time course analysis of MeHg exposure (30 ppm in drinking water) showed that whereas the ERAI signal was gradually attenuated at the late phase after increasing at the early phase, activation of the apoptotic pathway of the UPR was enhanced in proportion to the exposure time. These results suggest that MeHg induces not only ER stress but also neuronal cell death via a UPR shift. UPR modulation could be a therapeutic target for treating neuropathy caused by electrophiles similar to MeHg.
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Affiliation(s)
- Hideki Hiraoka
- Department of Medicinal Pharmacology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, 700-8530, Japan
| | - Ryosuke Nomura
- Department of Medicinal Pharmacology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, 700-8530, Japan
| | - Nobumasa Takasugi
- Department of Medicinal Pharmacology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, 700-8530, Japan
| | - Ryoko Akai
- Division of Cell Medicine, Department of Life Science, Medical Research Institute, Kanazawa Medical University, 1-1 Daigaku, Uchinada, Kahoku, Ishikawa, 920-0293, Japan
| | - Takao Iwawaki
- Division of Cell Medicine, Department of Life Science, Medical Research Institute, Kanazawa Medical University, 1-1 Daigaku, Uchinada, Kahoku, Ishikawa, 920-0293, Japan
| | - Yoshito Kumagai
- Environmental Biology Laboratory, Faculty of Medicine, University of Tsukuba, Ibaraki, 305-8575, Japan
| | - Masatake Fujimura
- Department of Basic Medical Science, National Institute for Minamata Disease, Kumamoto, 867-0008, Japan
| | - Takashi Uehara
- Department of Medicinal Pharmacology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, 700-8530, Japan.
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31
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Eiró LG, Ferreira MKM, Bittencourt LO, Aragão WAB, Souza MPCD, Silva MCF, Dionizio A, Buzalaf MAR, Crespo-López ME, Lima RR. Chronic methylmercury exposure causes spinal cord impairment: Proteomic modulation and oxidative stress. Food Chem Toxicol 2020; 146:111772. [DOI: 10.1016/j.fct.2020.111772] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 09/18/2020] [Accepted: 09/21/2020] [Indexed: 12/19/2022]
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Fujimura M, Usuki F. Methylmercury-Mediated Oxidative Stress and Activation of the Cellular Protective System. Antioxidants (Basel) 2020; 9:antiox9101004. [PMID: 33081221 PMCID: PMC7602710 DOI: 10.3390/antiox9101004] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 10/09/2020] [Accepted: 10/14/2020] [Indexed: 12/17/2022] Open
Abstract
Methylmercury (MeHg) is a well-known neurotoxicant that causes severe intoxication in humans. In Japan, it is referred to as Minamata disease, which involves two characteristic clinical forms: fetal type and adult type depending on the exposed age. In addition to MeHg burden level, individual susceptibility to MeHg plays a role in the manifestation of MeHg toxicity. Research progress has pointed out the importance of oxidative stress in the pathogenesis of MeHg toxicity. MeHg has a high affinity for selenohydryl groups, sulfhydryl groups, and selenides. It has been clarified that such affinity characteristics cause the impairment of antioxidant enzymes and proteins, resulting in the disruption of antioxidant systems. Furthermore, MeHg-induced intracellular selenium deficiency due to the greater affinity of MeHg for selenohydryl groups and selenides leads to failure in the recoding of a UGA codon for selenocysteine and results in the degradation of antioxidant selenoenzyme mRNA by nonsense-mediated mRNA decay. The defect of antioxidant selenoenzyme replenishment exacerbates MeHg-mediated oxidative stress. On the other hand, it has also been revealed that MeHg can directly activate the antioxidant Keap1/Nrf2 signaling pathway. This review summarizes the incidence of MeHg-mediated oxidative stress from the viewpoint of the individual intracellular redox system interactions and the MeHg-mediated aforementioned intracellular events. In addition, the mechanisms of cellular stress pathways and neuronal cell death triggered by MeHg-mediated oxidative stress and direct interactions of MeHg with reactive residues of proteins are mentioned.
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Affiliation(s)
- Masatake Fujimura
- Department of Basic Medical Sciences, National Institute for Minamata Disease, Kumamoto 867-0008, Japan;
| | - Fusako Usuki
- Division of Neuroimmunology, Joint Research Center for Human Retrovirus Infection, Kagoshima University, Kagoshima 890-8544, Japan
- Correspondence: ; Tel.: +81-99-275-6246; Fax: +81-99-275-5942
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Freire MAM, Lima RR, Nascimento PC, Gomes-Leal W, Pereira A. Effects of methylmercury on the pattern of NADPH diaphorase expression and astrocytic activation in the rat. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2020; 201:110799. [PMID: 32544743 DOI: 10.1016/j.ecoenv.2020.110799] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 05/18/2020] [Accepted: 05/22/2020] [Indexed: 06/11/2023]
Abstract
Mercury (Hg) is an environmental contaminant that poses great risk to human health. However, it is still widely used in artisanal gold-mining enterprises around the world, especially in developing countries. Methylmercury (MeHg) is produced environmentally by biomethylation of inorganic Hg present in water sediments, leading to its subsequent accumulation in the aquatic food chain. Due to its high metabolic rate, the Central Nervous System (CNS) is one of the main targets of MeHg. In the present study, we investigate the impact of chronic MeHg intoxication on NADPH diaphorase (NADPH-d) activity and astrocyte mobilization in the visual cortex of the rat. After 60 days of MeHg administration by oral gavage (0.04 mg/kg/day), tissue samples containing the visual cortex were submitted to measurements of Hg levels, NADPH-d activity, and GFAP immunohistochemistry for identification of astrocytes. MeHg intoxication was associated with increased Hg deposits and with reduced NADPH-d neuropil reactivity in the visual cortex. A morphometric analysis suggested that NADPH-d-positive neurons were mostly spared from MeHg harmful action and intoxicated animals had astrocytic activation similar to the control group. The decrease in NADPH-d neuropil reactivity may be due to the negative effect of chronic MeHg poisoning on both the synthesis and transport of this enzyme in afferent pathways to the visual cortex. The relative resistance of NADPH-d-reactive neurons to chronic MeHg intoxication may be associated with peculiarities in cell metabolism or to a protective role of nitric oxide, safeguarding those neurons from Hg deleterious effects.
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Affiliation(s)
- Marco Aurelio M Freire
- Graduate Program in Health and Society, Faculty of Health Sciences, University of State of Rio Grande do Norte (UERN), Mossoró, RN, Brazil
| | - Rafael Rodrigues Lima
- Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Pará (UFPA), Belém, PA, Brazil
| | - Priscila Cunha Nascimento
- Laboratory of Functional and Structural Biology, Institute of Biological Sciences, Federal University of Pará (UFPA), Belém, PA, Brazil
| | - Walace Gomes-Leal
- Laboratory of Experimental Neuroprotection and Neuroregeneration, Institute of Biological Sciences, Federal University of Pará (UFPA), Belém, PA, Brazil
| | - Antonio Pereira
- Department of Electrical and Biomedical Engineering, Institute of Technology, Federal University of Pará (UFPA), Belém, PA, Brazil.
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Chu JH, Yan YX, Gao PC, Chen XW, Fan RF. Response of selenoproteins gene expression profile to mercuric chloride exposure in chicken kidney. Res Vet Sci 2020; 133:4-11. [PMID: 32916514 DOI: 10.1016/j.rvsc.2020.08.020] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 08/13/2020] [Accepted: 08/30/2020] [Indexed: 12/26/2022]
Abstract
Kidney is a primary target organ for mercuric chloride (HgCl2) toxicity. Selenium (Se) can exert antagonistic effect on heavy metals-induced organ toxicity by regulating the expression of selenoproteins. The objective of this study was to investigate the effect of HgCl2 on the gene expression of selenoproteins in chicken kidney. Sixty male Hyline brown chickens were randomly and evenly divided into two groups. After acclimatization for one week, chickens were provided with the standard diet as well as non-treated water (CON group), and standard diet as well as HgCl2-treated water (250 ppm, HgCl2 group). After seven weeks, kidney tissues were collected to examine the mRNA expression levels of 25 selenoproteins genes and protein expression levels of 4 selenoproteins. Moreover, correlation analysis and principal component analysis (PCA) were used to analyze the expression patterns of 25 selenoproteins. The results showed that HgCl2 exposure significantly decreased the mRNA expression of Glutathione peroxidase 1 (GPX1), GPX4, Thioredoxin reductase 2 (TXNRD2), Iodothyronine deiodinase 1 (DIO1), Methionine-Rsulfoxide reductase 1 (SELR), 15-kDa selenoprotein (SEP15), selenoprotein I (SELI), SELK, SELM, SELN, SELP, SELS, SELT, SELW, and SEPHS2. Meanwhile, HgCl2 exposure significantly increased the mRNA expression of GPX3, TXNRD1, and SELU. Western blot analysis showed that the expression levels of GPX3, TXNRD1, SELK, and SELN were concordant with these mRNA expression levels. Analysis results of selenoproteins expression patterns showed that HgCl2-induced the main disorder expression of selenoproteins with antioxidant activity and endoplasmic reticulum resident selenoproteins. In conclusion, selenoproteins respond to HgCl2 exposure in a characteristic manner in chicken kidney.
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Affiliation(s)
- Jia-Hong Chu
- College of Animal Science and Veterinary Medicine, Shandong Agricultural University, 61 Daizong Street, Tai'an City, Shandong Province 271018, China; Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, Shandong Agricultural University, 61 Daizong Street, Tai'an City, Shandong Province 271018, China; Shandong Provincial Engineering Technology Research Center of Animal Disease Control and Prevention, Shandong Agricultural University, 61 Daizong Street, Tai'an City, Shandong Province 271018, China
| | - Yu-Xue Yan
- College of Animal Science and Veterinary Medicine, Shandong Agricultural University, 61 Daizong Street, Tai'an City, Shandong Province 271018, China; Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, Shandong Agricultural University, 61 Daizong Street, Tai'an City, Shandong Province 271018, China; Shandong Provincial Engineering Technology Research Center of Animal Disease Control and Prevention, Shandong Agricultural University, 61 Daizong Street, Tai'an City, Shandong Province 271018, China
| | - Pei-Chao Gao
- College of Animal Science and Veterinary Medicine, Shandong Agricultural University, 61 Daizong Street, Tai'an City, Shandong Province 271018, China; Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, Shandong Agricultural University, 61 Daizong Street, Tai'an City, Shandong Province 271018, China; Shandong Provincial Engineering Technology Research Center of Animal Disease Control and Prevention, Shandong Agricultural University, 61 Daizong Street, Tai'an City, Shandong Province 271018, China
| | - Xue-Wei Chen
- College of Animal Science and Veterinary Medicine, Shandong Agricultural University, 61 Daizong Street, Tai'an City, Shandong Province 271018, China; Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, Shandong Agricultural University, 61 Daizong Street, Tai'an City, Shandong Province 271018, China; Shandong Provincial Engineering Technology Research Center of Animal Disease Control and Prevention, Shandong Agricultural University, 61 Daizong Street, Tai'an City, Shandong Province 271018, China
| | - Rui-Feng Fan
- College of Animal Science and Veterinary Medicine, Shandong Agricultural University, 61 Daizong Street, Tai'an City, Shandong Province 271018, China; Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, Shandong Agricultural University, 61 Daizong Street, Tai'an City, Shandong Province 271018, China; Shandong Provincial Engineering Technology Research Center of Animal Disease Control and Prevention, Shandong Agricultural University, 61 Daizong Street, Tai'an City, Shandong Province 271018, China.
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Chen N, Tang X, Ye Z, Wang S, Xiao X. Methylmercury disrupts autophagic flux by inhibiting autophagosome-lysosome fusion in mouse germ cells. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2020; 198:110667. [PMID: 32339925 DOI: 10.1016/j.ecoenv.2020.110667] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 04/03/2020] [Accepted: 04/19/2020] [Indexed: 06/11/2023]
Abstract
Methylmercury (MeHg) is an extremely toxic environmental pollutant that can cause serious male reproductive developmental dysplasia in humans and animals. However, the molecular mechanisms underlying MeHg-induced male reproductive injury are not fully clear. The purpose of this study was to explore whether mitophagy and lysosome dysfunction contribute to MeHg-induced apoptosis of germ cell and to determine the potential mechanism. First, we confirmed the exposure of GC2-spd cells to mercury. In GC2-spd cells (a mouse spermatocyte cell line), we found that MeHg treatment led to an obvious increase of cell apoptosis accompanied by a marked rise of LC3-II expression and an elevated number of autophagosomes. These results were associated with the induction of oxidative stress and mitophagy. Interestingly, we found that MeHg did not promote but prevented autophagosome-lysosome fusion by impairing the lysosome function. Furthermore, as a lysosome inhibitor, chloroquine pre-treatment obviously enhanced LC3-II expression and mitophagy formation in MeHg-treated cells. This further proved that the induction of mitophagy and the injury of the lysosome played an important role in the GC2-spd cell apoptosis induced by MeHg. Our findings indicate that MeHg caused apoptosis in the GC2-spd cells, which were dependent on oxidative stress-mediated mitophagy and the lysosome damaging-mediated inhibition of autophagic flux induced by MeHg.
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Affiliation(s)
- Na Chen
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, PR China
| | - Xiaofeng Tang
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, PR China
| | - Zhaoyang Ye
- Maternal and Child Health Hospital of Hubei Province, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, PR China
| | - Shanshan Wang
- Key Laboratory of Agro-product Safety and Quality, Institute of Quality Standards & Testing Technology for Agro-Products, Chinese Academy of Agricultural Sciences, Beijing, 100081, PR China.
| | - Xianjin Xiao
- Institute of Reproductive Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, PR China.
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Adiponectin ameliorates lung injury induced by intermittent hypoxia through inhibition of ROS-associated pulmonary cell apoptosis. Sleep Breath 2020; 25:459-470. [PMID: 32458376 DOI: 10.1007/s11325-020-02103-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Revised: 04/23/2020] [Accepted: 05/07/2020] [Indexed: 12/21/2022]
Abstract
PURPOSE Obstructive sleep apnea hypopnea syndrome has been reported to be associated with pulmonary hypertension (PH). Adiponectin (Ad) has many protective roles in the human body, including its function as an anti-inflammatory and an anti-oxidant, as well as its role in preventing insulin resistance and atherosclerosis. This study aimed to investigate the molecular mechanism of chronic intermittent hypoxia (CIH)-induced pulmonary injury and the protective role of Ad in experimental rats. METHODS Thirty male Sprague-Dawley rats were randomly divided into three groups with 10 rats in each group: normal control (NC) group, CIH group, and CIH + Ad group. Rats in the NC group were kept breathing room air for 12 weeks. Rats in the CIH group were intermittently exposed to a hypoxic environment for 8 h/day for 12 weeks. Rats in the CIH + Ad group received 10 μg Ad twice weekly via intravenous injection. After 12 weeks of CIH exposure, we detected the pulmonary function, pulmonary artery pressure, lung histology, pulmonary cell apoptosis, pulmonary artery endothelial cell apoptosis, mitochondrial membrane potential (MMP), and reactive oxygen species (ROS) level. We also analyzed expression proteins involved in the mitochondria-, endoplasmic reticulum (ER) stress-, and Fas receptor-associated pulmonary apoptosis pathways, as well as the SIRT3/SOD2 pathway. RESULTS CIH exposure for 12 weeks did not lead to abnormal pulmonary function, PH, or pulmonary artery endothelial cell apoptosis. However, we observed a significant increase in the rate of pulmonary cell apoptosis, the expression of proteins involved in mitochondria-, ER stress-, and Fas receptor-associated pulmonary apoptosis pathways, and the generation of ROS in the CIH group compared with the NC group. In contrast, the MMP and protein expressions of SIRT3/SOD2 pathway were significantly decreased in the CIH group compared with the NC group. Ad supplementation in the CIH + Ad group partially improved these changes induced by CIH. CONCLUSION Even though CIH did not cause abnormal pulmonary function or PH, early lung injury was detected at the molecular level in rats exposed to CIH. Treatment with Ad ameliorated the pulmonary injury by activating the SIRT3/SOD2 pathway, reducing ROS generation, and inhibiting ROS-associated lung cell apoptosis.
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Rojas-Franco P, Franco-Colín M, Torres-Manzo AP, Blas-Valdivia V, Thompson-Bonilla MDR, Kandir S, Cano-Europa E. Endoplasmic reticulum stress participates in the pathophysiology of mercury-caused acute kidney injury. Ren Fail 2020; 41:1001-1010. [PMID: 31736398 PMCID: PMC6882499 DOI: 10.1080/0886022x.2019.1686019] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Acute exposure to mercury chloride (HgCl2) causes acute kidney injury (AKI). Some metals interfere with protein folding, leading to endoplasmic reticulum stress (ERS), and the activation of cell death mechanisms, but in the case of mercury, there is no knowledge about whether the ERS mediates tubular damage. This study aimed to determinate if HgCl2 causes an AKI course with temporary activation of ERS and if this mechanism is involved in kidney cell death. Male mice were intoxicated with 5 mg/kg HgCl2 and sacrificed after 24, 48, 72, and 96 h of mercury administration. The kidneys of euthanized mice were used to assess the renal function, oxidative stress, redox environment, antioxidant enzymatic system, cell death, and reticulum stress markers (PERK, ATF-6, and IRE1α pathways). The results indicate temporary-dependent renal dysfunction, oxidative stress, and an increase of glutathione-dependent enzymes involved in the bioaccumulation process of mercury, as well as the enhancement of caspase 3 activity along with IRE1a, GADD-153, and caspase 12 expressions. Mercury activates the PERK/eIF2α branch during the first 48 h. Meanwhile, the activation of PERK/ATF-4 branch allowed for ATF-4, ATF-6, and IRE1α pathways to enhance GADD-153. It led to the activation of caspases 12 and 3, which mediated the deaths of the tubular and glomerular cells. This study revealed temporary-dependent ERS present during AKI caused by HgCl2, as well as how it plays a pivotal role in kidney cell damage.
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Affiliation(s)
- Plácido Rojas-Franco
- Laboratorio de Metabolismo I Departamento de Fisiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Ciudad de México, México
| | - Margarita Franco-Colín
- Laboratorio de Metabolismo I Departamento de Fisiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Ciudad de México, México
| | | | - Vanessa Blas-Valdivia
- Laboratorio de Neurobiología, Departamento de Fisiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Ciudad de México, México
| | | | - Sinan Kandir
- Department of Physiology, Ceyhan Faculty of Veterinary Medicine, Cukurova University, Adana, Turkey
| | - Edgar Cano-Europa
- Laboratorio de Metabolismo I Departamento de Fisiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Ciudad de México, México
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Aaseth J, Wallace DR, Vejrup K, Alexander J. Methylmercury and developmental neurotoxicity: A global concern. CURRENT OPINION IN TOXICOLOGY 2020. [DOI: 10.1016/j.cotox.2020.01.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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Ashrafizadeh M, Mohammadinejad R, Samarghandian S, Yaribeygi H, Johnston TP, Sahebkar A. Anti-Tumor Effects of Osthole on Different Malignant Tissues: A Review of Molecular Mechanisms. Anticancer Agents Med Chem 2020; 20:918-931. [PMID: 32108003 DOI: 10.2174/1871520620666200228110704] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 12/09/2019] [Accepted: 01/29/2020] [Indexed: 12/16/2022]
Abstract
Cancer management and/or treatment require a comprehensive understanding of the molecular and signaling pathways involved. Recently, much attention has been directed to these molecular and signaling pathways, and it has been suggested that a number of biomolecules/players involved in such pathways, such as PI3K/Akt, NF-kB, STAT, and Nrf2 contribute to the progression, invasion, proliferation, and metastasis of malignant cells. Synthetic anti-tumor agents and chemotherapeutic drugs have been a mainstay in cancer therapy and are widely used to suppress the progression and, hopefully, halt the proliferation of malignant cells. However, these agents have some undesirable side-effects and, therefore, naturally-occurring compounds with high potency and fewer side-effects are now of great interest. Osthole is a plant-derived chemical compound that can inhibit the proliferation of malignant cells and provide potent anti-cancer effects in various tissues. Therefore, in this review, we presented the main findings concerning the potential anti-tumor effects of osthole and its derivatives and described possible molecular mechanisms by which osthole may suppress malignant cell proliferation in different tissues.
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Affiliation(s)
- Milad Ashrafizadeh
- Department of Basic Science, Faculty of Veterinary Medicine, University of Tabriz, Tabriz, Iran
| | - Reza Mohammadinejad
- Pharmaceutics Research Center, Institute of Neuropharmacology, Kerman University of Medical Sciences, Kerman, Iran
| | - Saeed Samarghandian
- Department of Basic Medical Sciences, Neyshabur University of Medical Sciences, Neyshabur, Iran
| | - Habib Yaribeygi
- Research Center of Physiology, Semnan University of Medical Sciences, Semnan, Iran
| | - Thomas P Johnston
- Division of Pharmacology and Pharmaceutical Sciences, School of Pharmacy, University of Missouri-Kansas City, Kansas City, MO, United States
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Cordeiro ER, Filetti FM, Simões MR, Vassallo DV. Mercury induces nuclear estrogen receptors to act as vasoconstrictors promoting endothelial denudation via the PI3K/Akt signaling pathway. Toxicol Appl Pharmacol 2019; 381:114710. [PMID: 31415774 DOI: 10.1016/j.taap.2019.114710] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Revised: 07/29/2019] [Accepted: 08/10/2019] [Indexed: 10/26/2022]
Abstract
Cardiovascular diseases (CVD) are more frequent among postmenopausal women due to the decline of estrogen concentration in plasma. However, the role of the vascular modulator effect of estrogen is controversial, since it occurs both in physiological and pathological conditions, increasing or reducing vascular reactivity. As mercury is widely associated with the development of CVD, we investigated putative hazardous effects on the mechanisms that modulate vascular reactivity in aortic rings of female Wistar rats promoted by acute mercury exposure. Mercury increased vascular reactivity and oxidative stress possibly due to NADPH oxidase participation, increased production of cyclooxygenase-2 (COX-2) and thromboxane A2 (TXA2) formation. The metal also induced endothelial denudation in the aorta by reducing the bioavailability of nitric oxide (NO) and enhancing the activity of the PI3K/Akt signaling pathway. Mercury exposure also induced nuclear estrogen receptors (ERα, ERβ) to act as vasoconstrictors. Our findings suggest that mercury might increase the chances of developing cardiovascular diseases in females and should be considered an important environmental risk factor.
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Affiliation(s)
- Evellyn Rodrigues Cordeiro
- Dept. of Physiological Sciences, Universidade Federal do Espírito Santo, Vitória, ES CEP 29043-900, Brazil
| | - Filipe Martinuzo Filetti
- Dept. of Physiological Sciences, Universidade Federal do Espírito Santo, Vitória, ES CEP 29043-900, Brazil
| | - Maylla Ronacher Simões
- Dept. of Physiological Sciences, Universidade Federal do Espírito Santo, Vitória, ES CEP 29043-900, Brazil
| | - Dalton Valentim Vassallo
- Dept. of Physiological Sciences, Universidade Federal do Espírito Santo, Vitória, ES CEP 29043-900, Brazil; Health Science Center of Vitória-EMESCAM, Vitória, ES CEP 29045-402, Brazil.
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Takasugi N, Hiraoka H, Nakahara K, Akiyama S, Fujikawa K, Nomura R, Furuichi M, Uehara T. The Emerging Role of Electrophiles as a Key Regulator for Endoplasmic Reticulum (ER) Stress. Int J Mol Sci 2019; 20:E1783. [PMID: 30974903 PMCID: PMC6480251 DOI: 10.3390/ijms20071783] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Revised: 03/28/2019] [Accepted: 04/08/2019] [Indexed: 12/13/2022] Open
Abstract
The unfolded protein response (UPR) is activated by the accumulation of misfolded proteins in the endoplasmic reticulum (ER), which is called ER stress. ER stress sensors PERK, IRE1, and ATF6 play a central role in the initiation and regulation of the UPR; they inhibit novel protein synthesis and upregulate ER chaperones, such as protein disulfide isomerase, to remove unfolded proteins. However, when recovery from ER stress is difficult, the UPR pathway is activated to eliminate unhealthy cells. This signaling transition is the key event of many human diseases. However, the precise mechanisms are largely unknown. Intriguingly, reactive electrophilic species (RES), which exist in the environment or are produced through cellular metabolism, have been identified as a key player of this transition. In this review, we focused on the function of representative RES: nitric oxide (NO) as a gaseous RES, 4-hydroxynonenal (HNE) as a lipid RES, and methylmercury (MeHg) as an environmental organic compound RES, to outline the relationship between ER stress and RES. Modulation by RES might be a target for the development of next-generation therapy for ER stress-associated diseases.
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Affiliation(s)
- Nobumasa Takasugi
- Department of Medicinal Pharmacology, Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University, Okayama 700-8530, Japan.
| | - Hideki Hiraoka
- Department of Medicinal Pharmacology, Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University, Okayama 700-8530, Japan.
| | - Kengo Nakahara
- Department of Medicinal Pharmacology, Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University, Okayama 700-8530, Japan.
| | - Shiori Akiyama
- Department of Medicinal Pharmacology, Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University, Okayama 700-8530, Japan.
| | - Kana Fujikawa
- Department of Medicinal Pharmacology, Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University, Okayama 700-8530, Japan.
| | - Ryosuke Nomura
- Department of Medicinal Pharmacology, Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University, Okayama 700-8530, Japan.
| | - Moeka Furuichi
- Department of Medicinal Pharmacology, Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University, Okayama 700-8530, Japan.
| | - Takashi Uehara
- Department of Medicinal Pharmacology, Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Okayama University, Okayama 700-8530, Japan.
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