title: 2, 3, 7, 8-Tetrachlorodibenzo-P-dioxin (TCDD) induces premature senescence in human and rodent neuronal cells via ROS-dependent mechanisms.
abstract: The widespread environmental pollutant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is a potent toxicant that causes significant neurotoxicity. However, the biological events that participate in this process remain largely elusive. In the present study, we demonstrated that TCDD exposure triggered apparent premature senescence in rat pheochromocytoma (PC12) and human neuroblastoma SH-SY5Y cells. Senescence-associated β-galactosidase (SA-β-Gal) assay revealed that TCDD induced senescence in PC12 neuronal cells at doses as low as 10 nM. TCDD led to F-actin reorganization and the appearance of an alternative senescence marker, γ-H2AX foci, both of which are important features of cellular senescence. In addition, TCDD exposure altered the expression of senescence marker proteins, such as p16, p21 and p-Rb, in both dose- and time-dependent manners. Furthermore, we demonstrated that TCDD promotes mitochondrial dysfunction and the accumulation of cellular reactive oxygen species (ROS) in PC12 cells, leading to the activation of signaling pathways that are involved in ROS metabolism and senescence. TCDD-induced ROS generation promoted significant oxidative DNA damage and lipid peroxidation. Notably, treatment with the ROS scavenger N-acetylcysteine (NAC) markedly attenuated TCDD-induced ROS production, cellular oxidative damage and neuronal senescence. Moreover, we found that TCDD induced a similar ROS-mediated senescence response in human neuroblastoma SH-SY5Y cells. In sum, these results demonstrate for the first time that TCDD induces premature senescence in neuronal cells by promoting intracellular ROS production, supporting the idea that accelerating the onset of neuronal senescence may be an important mechanism underlying TCDD-induced neurotoxic effects.
authors.affiliation: Department of Nutrition and Food Hygiene, School of Public Health, Nantong University, Nantong, Jiangsu, People's Republic of China.
authors.forename: Chunhua
authors.initials: C
authors.lastname: Wan
authors.affiliation: Department of Nutrition and Food Hygiene, School of Public Health, Nantong University, Nantong, Jiangsu, People's Republic of China.
authors.forename: Jiao
authors.initials: J
authors.lastname: Liu
authors.affiliation: Department of Nutrition and Food Hygiene, School of Public Health, Nantong University, Nantong, Jiangsu, People's Republic of China.
authors.forename: Xiaoke
authors.initials: X
authors.lastname: Nie
authors.affiliation: Department of Nutrition and Food Hygiene, School of Public Health, Nantong University, Nantong, Jiangsu, People's Republic of China.
authors.forename: Jianya
authors.initials: J
authors.lastname: Zhao
authors.affiliation: Department of Nutrition and Food Hygiene, School of Public Health, Nantong University, Nantong, Jiangsu, People's Republic of China.
authors.forename: Songlin
authors.initials: S
authors.lastname: Zhou
authors.affiliation: Department of Nutrition and Food Hygiene, School of Public Health, Nantong University, Nantong, Jiangsu, People's Republic of China.
authors.forename: Zhiqing
authors.initials: Z
authors.lastname: Duan
authors.affiliation: Department of Nutrition and Food Hygiene, School of Public Health, Nantong University, Nantong, Jiangsu, People's Republic of China.
authors.forename: Cuiying
authors.initials: C
authors.lastname: Tang
authors.affiliation: Department of Nutrition and Food Hygiene, School of Public Health, Nantong University, Nantong, Jiangsu, People's Republic of China.
authors.forename: Lingwei
authors.initials: L
authors.lastname: Liang
authors.affiliation: Department of Nutrition and Food Hygiene, School of Public Health, Nantong University, Nantong, Jiangsu, People's Republic of China.
authors.forename: Guangfei
authors.initials: G
authors.lastname: Xu
mesh_terms: D000199:Actins / Q000378:metabolism; D000704:Analysis of Variance; D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D015153:Blotting, Western; D016922:Cellular Senescence / Q000187:drug effects*; D004249:DNA Damage / Q000187:drug effects; D017931:DNA Primers / Q000235:genetics; D004305:Dose-Response Relationship, Drug; D004785:Environmental Pollutants / Q000378:metabolism / Q000633:toxicity*; D005453:Fluorescence; D006657:Histones / Q000378:metabolism; D006801:Humans; D015227:Lipid Peroxidation / Q000187:drug effects; D009417:Nerve Tissue / Q000166:cytology / Q000187:drug effects*; D016716:PC12 Cells; D010750:Phosphoproteins / Q000378:metabolism; D000072317:Polychlorinated Dibenzodioxins / Q000378:metabolism / Q000633:toxicity*; D051381:Rats; D017382:Reactive Oxygen Species / Q000378:metabolism*; D060888:Real-Time Polymerase Chain Reaction; D013997:Time Factors; D001616:beta-Galactosidase / Q000378:metabolism
chemical_list: D000199:Actins; D015415:Biomarkers; D017931:DNA Primers; D004785:Environmental Pollutants; D006657:Histones; D010750:Phosphoproteins; D000072317:Polychlorinated Dibenzodioxins; D017382:Reactive Oxygen Species; C577575:gamma-H2AX protein, rat; D001616:beta-Galactosidase