title: NADPH oxidase activation is required for pentylenetetrazole kindling-induced hippocampal autophagy.
abstract: Growing evidence indicates that alterations in autophagy are present in a variety of neurological disorders, ranging from neurodegenerative diseases to acute neurological insults. Only recently has the role of autophagy in epilepsy started to be recognized. In this study, we used pentylenetetrazole (PTZ) kindling, which provides a model of chronic epilepsy, to investigate the involvement of autophagy in the hippocampus and the possible mechanisms involved. Our western blot results showed that autophagy-related proteins were significantly increased after the mice were fully kindled. In addition, immunofluorescence studies revealed a significant increase in the punctate accumulation of LC3 in the hippocampal CA1 region of fully PTZ-kindled mice. Consistent with the upregulation of ATG proteins and punctate accumulation of LC3 in the hippocampal CA1 region, autophagosomal vacuole formation was observed by an ultrastructural analysis, verifying the presence of a hippocampal autophagic response in PTZ-kindled mice. Increased oxidative stress has been postulated to play an important role in the pathogenesis of a number of neurological diseases, including epilepsy. In this study, we demonstrate that PTZ kindling induced reactive oxygen species (ROS) production and lipid peroxidation, which were accompanied by mitochondrial ultrastructural damage due to the activation of NADPH oxidase. Pharmacological inhibition of NADPH oxidase by apocynin significantly suppressed the oxidative stress and ameliorated the hippocampal autophagy in PTZ-kindled mice. Interestingly, pharmacological induction of autophagy suppressed PTZ-kindling progress and reduced PTZ-kindling-induced oxidative stress while inhibition of autophagy accelerated PTZ kindling progress and increased PTZ-kindling-induced oxidative stress. These results suggest that the oxidative stress induced by NADPH oxidase activation may play a pivotal role in PTZ-kindling process as well as in PTZ kindling-induced hippocampal CA1 autophagy.
authors.affiliation: Department of Pharmacology, Medical School of Southeast University, 87th Dingjiaqiao Road, Nanjing 210029, China. Electronic address: xinjianzhu@seu.edu.cn.
authors.forename: Xinjian
authors.initials: X
authors.lastname: Zhu
authors.affiliation: Department of Pharmacology, Medical School of Southeast University, 87th Dingjiaqiao Road, Nanjing 210029, China.
authors.forename: Kai
authors.initials: K
authors.lastname: Shen
authors.affiliation: Department of Pharmacology, Medical School of Southeast University, 87th Dingjiaqiao Road, Nanjing 210029, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Bai
authors.affiliation: Department of Pathology, Medical School of Southeast University, Nanjing, China.
authors.forename: Aifeng
authors.initials: A
authors.lastname: Zhang
authors.affiliation: Analysis and Test Center of Nanjing Medical University, Nanjing, China.
authors.forename: Zhengrong
authors.initials: Z
authors.lastname: Xia
authors.affiliation: Department of Physiology, Medical School of Southeast University, Nanjing, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Chao
authors.affiliation: Department of Pharmacology, Medical School of Southeast University, 87th Dingjiaqiao Road, Nanjing 210029, China.
authors.forename: Honghong
authors.initials: H
authors.lastname: Yao
mesh_terms: D000818:Animals; D001343:Autophagy / Q000187:drug effects*; D001931:Brain Mapping; D004195:Disease Models, Animal; D004827:Epilepsy / Q000139:chemically induced / Q000378:metabolism* / Q000503:physiopathology; D006624:Hippocampus / Q000187:drug effects* / Q000503:physiopathology; D006801:Humans; D007696:Kindling, Neurologic / Q000187:drug effects; D015227:Lipid Peroxidation / Q000187:drug effects; D051379:Mice; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D008928:Mitochondria / Q000378:metabolism* / Q000473:pathology / Q000648:ultrastructure; D019255:NADPH Oxidases / Q000235:genetics*; D018384:Oxidative Stress / Q000187:drug effects / Q000235:genetics; D010433:Pentylenetetrazole / Q000633:toxicity; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: C480860:Map1lc3b protein, mouse; D008869:Microtubule-Associated Proteins; D017382:Reactive Oxygen Species; D019255:NADPH Oxidases; D010433:Pentylenetetrazole
keywords: Autophagy; Epilepsy; NADPH oxidase; PTZ kindling; ROS