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Hexachloronaphthalene Induces Mitochondrial-Dependent Neurotoxicity via a Mechanism of Enhanced Production of Reactive Oxygen Species. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2020; 2020:2479234. [PMID: 32685088 PMCID: PMC7335409 DOI: 10.1155/2020/2479234] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Accepted: 06/09/2020] [Indexed: 12/30/2022]
Abstract
Hexachloronaphthalene (PCN67) is one of the most toxic among polychlorinated naphthalenes. Despite the known high bioaccumulation and persistence of PCN67 in the environment, it is still unclear to what extent exposure to these substances may interfere with normal neuronal physiology and lead to neurotoxicity. Therefore, the primary goal of this study was to assess the effect of PCN67 in neuronal in vitro models. Neuronal death was assessed upon PCN67 treatment using differentiated PC12 cells and primary hippocampal neurons. At 72 h postexposure, cell viability assays showed an IC50 value of 0.35 μg/ml and dose-dependent damage of neurites and concomitant downregulation of neurofilaments L and M. Moreover, we found that younger primary neurons (DIV4) were much more sensitive to PCN67 toxicity than mature cultures (DIV14). Our comprehensive analysis indicated that the application of PCN67 at the IC50 concentration caused necrosis, which was reflected by an increase in LDH release, HMGB1 protein export to the cytosol, nuclear swelling, and loss of homeostatic control of energy balance. The blockage of mitochondrial calcium uniporter partially rescued the cell viability, loss of mitochondrial membrane potential (ΔΨm), and the overproduction of reactive oxygen species, suggesting that the underlying mechanism of neurotoxicity involved mitochondrial calcium accumulation. Increased lipid peroxidation as a consequence of oxidative stress was additionally seen for 0.1 μg/ml of PCN67, while this concentration did not affect ΔΨm and plasma membrane permeability. Our results show for the first time that neuronal mitochondria act as a target for PCN67 and indicate that exposure to this drug may result in neuron loss via mitochondrial-dependent mechanisms.
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Jiang J, Duan Z, Nie X, Xi H, Li A, Guo A, Wu Q, Jiang S, Zhao J, Chen G. Activation of neuronal nitric oxide synthase (nNOS) signaling pathway in 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-induced neurotoxicity. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2014; 38:119-130. [PMID: 24930124 DOI: 10.1016/j.etap.2014.05.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Revised: 05/07/2014] [Accepted: 05/09/2014] [Indexed: 06/03/2023]
Abstract
2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) has been reported to cause alterations in cognitive and motor behavior during both development and adulthood. In this study, the neuronal nitric oxide synthase (nNOS) signaling pathway was investigated in differentiated pheochromocytoma (PC12) cells to better understand the mechanisms of TCDD-induced neurotoxicity. TCDD exposure induced a time- and dose-dependent increase in nNOS expression. High levels of nitric oxide (NO) production by nNOS activation induced mitochondrial cytochrome c (Cyt-c) release and down-regulation of Bcl-2. Additionally, TCDD increased the expression of active caspase-3 and significantly led to apoptosis in PC12 cells. However, these effects above could be effectively inhibited by the addition of 7-nitroindazole (7-NI), a highly selective nNOS inhibitor. Moreover, in the brain cortex of Sprague-Dawley (SD) rats, nNOS was also found to have certain relationship with TCDD-induced neuronal apoptosis. Together, our findings establish a role for nNOS as an enhancer of TCDD-induced apoptosis in PC12 cells.
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Affiliation(s)
- Junkang Jiang
- Department of Occupational Medicine and Environmental Toxicology, School of Public Health, Nantong University, Nantong, 226001 Jiangsu, People's Republic of China
| | - Zhiqing Duan
- Department of Nutrition and Food Hygiene, School of Public Health, Nantong University, Nantong, 226001 Jiangsu, People's Republic of China
| | - Xiaoke Nie
- Department of Nutrition and Food Hygiene, School of Public Health, Nantong University, Nantong, 226001 Jiangsu, People's Republic of China
| | - Hanqing Xi
- Department of Occupational Medicine and Environmental Toxicology, School of Public Health, Nantong University, Nantong, 226001 Jiangsu, People's Republic of China
| | - Aihong Li
- Department of Occupational Medicine and Environmental Toxicology, School of Public Health, Nantong University, Nantong, 226001 Jiangsu, People's Republic of China
| | - Aisong Guo
- Department of Occupational Medicine and Environmental Toxicology, School of Public Health, Nantong University, Nantong, 226001 Jiangsu, People's Republic of China
| | - Qiyun Wu
- Department of Nutrition and Food Hygiene, School of Public Health, Nantong University, Nantong, 226001 Jiangsu, People's Republic of China
| | - Shengyang Jiang
- Department of Occupational Medicine and Environmental Toxicology, School of Public Health, Nantong University, Nantong, 226001 Jiangsu, People's Republic of China
| | - Jianya Zhao
- Department of Nutrition and Food Hygiene, School of Public Health, Nantong University, Nantong, 226001 Jiangsu, People's Republic of China
| | - Gang Chen
- Department of Occupational Medicine and Environmental Toxicology, School of Public Health, Nantong University, Nantong, 226001 Jiangsu, People's Republic of China.
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Panzica GC, Bo E, Martini MA, Miceli D, Mura E, Viglietti-Panzica C, Gotti S. Neuropeptides and enzymes are targets for the action of endocrine disrupting chemicals in the vertebrate brain. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART B, CRITICAL REVIEWS 2011; 14:449-72. [PMID: 21790321 DOI: 10.1080/10937404.2011.578562] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Endocrine-disrupting chemicals (EDC) are molecules that interfere with endocrine signaling pathways and produce adverse consequences on animal and human physiology, such as infertility or behavioral alterations. Some EDC act through binding to androgen or/and estrogen receptors primarily operating through a genomic mechanism regulating gene expression. This mechanism of action may induce profound developmental adverse effects, and the major targets of the EDC action are the gene products, i.e., mRNAs inducing the synthesis of various peptidic molecules, which include neuropeptides and enzymes related to neurotransmitters syntheses. Available immunohistochemical data on some of the systems that are affected by EDC in lower and higher vertebrates are detailed in this review.
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Affiliation(s)
- G C Panzica
- Laboratory of Neuroendocrinology, Department of Anatomy, Pharmacology, and Forensic Medicine, Neuroscience Institute of Turin (NIT), University of Torino, Torino, Italy.
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Dioxins, the aryl hydrocarbon receptor and the central regulation of energy balance. Front Neuroendocrinol 2010; 31:452-78. [PMID: 20624415 DOI: 10.1016/j.yfrne.2010.07.002] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2010] [Revised: 06/15/2010] [Accepted: 07/05/2010] [Indexed: 01/03/2023]
Abstract
Dioxins are ubiquitous environmental contaminants that have attracted toxicological interest not only for the potential risk they pose to human health but also because of their unique mechanism of action. This mechanism involves a specific, phylogenetically old intracellular receptor (the aryl hydrocarbon receptor, AHR) which has recently proven to have an integral regulatory role in a number of physiological processes, but whose endogenous ligand is still elusive. A major acute impact of dioxins in laboratory animals is the wasting syndrome, which represents a puzzling and dramatic perturbation of the regulatory systems for energy balance. A single dose of the most potent dioxin, TCDD, can permanently readjust the defended body weight set-point level thus providing a potentially useful tool and model for physiological research. Recent evidence of response-selective modulation of AHR action by alternative ligands suggests further that even therapeutic implications might be possible in the future.
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