title: Identification of the key molecules involved in chronic copper exposure-aggravated memory impairment in transgenic mice of Alzheimer's disease using proteomic analysis.
abstract: Alzheimer's disease (AD) is the most common neurodegenerative disease characterized by a progressive impairment of cognitive functions including spatial learning and memory. Excess copper exposure accelerates the development of AD; however, the potential mechanisms by which copper exacerbates the symptoms of AD remain unknown. In this study, we explored the effects of chronic copper exposure on cognitive function by treating 6 month-old triple AD transgenic (3xTg-AD) mice with 250 ppm copper sulfate in drinking water for 6 months, and identified several potential key molecules involved in the effects of chronic copper exposure on memory by proteomic analysis. The behavioral test showed that chronic copper exposure aggravated memory impairment of 3xTg-AD mice. Two-dimensional fluorescence difference gel electrophoresis (2D-DIGE) coupled with mass spectrometry revealed a total of 44 differentially expressed proteins (18 upregulated and 26 down-regulated) in hippocampus between the wild-type (WT) mice and non-exposed 3xTg-AD mice. A total of 40 differentially expressed proteins were revealed (20 upregulated and 20 down-regulated) in hippocampus between copper exposed and non-exposed 3xTg-AD mice. Among these differentially expressed proteins, complexin-1 and complexin-2, two memory associated proteins, were significantly decreased in hippocampus of 3xTg-AD mice compared with the WT mice. Furthermore, the expression of these two proteins was further down-regulated in 3xTg-AD mice when exposed to copper. The abnormal expression of complexin-1 and complexin-2 identified by proteomic analysis was verified by western blot analysis. Taken together, our data showed that chronic copper exposure accelerated memory impairment and altered the expression of proteins in hippocampus in 3xTg-AD mice. The functional analysis on the differentially expressed proteins suggested that complexin-1 and complexin-2 may be the key molecules involved in chronic copper exposure-aggravated memory impairment in AD.
authors.affiliation: College of Pharmacy, Jinan University, Guangdong, China Key Laboratory of Modern Toxicology of Shenzhen, Medical Key Laboratory of Guangdong Province, Medical Key Laboratory of Health Toxicology of Shenzhen, Shenzhen Center for Disease Control and Prevention, Shenzhen, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Yu
authors.affiliation: Shen Zhen Kai-Tuo Biotech, Shenzhen, China Guang Zhou Kai-Tuo Biotech, Guangzhou, China.
authors.forename: Xiaobin
authors.initials: X
authors.lastname: Luo
authors.affiliation: College of Pharmacy, Jinan University, Guangdong, China.
authors.forename: Hua
authors.initials: H
authors.lastname: Xu
authors.affiliation: Key Laboratory of Modern Toxicology of Shenzhen, Medical Key Laboratory of Guangdong Province, Medical Key Laboratory of Health Toxicology of Shenzhen, Shenzhen Center for Disease Control and Prevention, Shenzhen, China.
authors.forename: Quan
authors.initials: Q
authors.lastname: Ma
authors.affiliation: Key Laboratory of Modern Toxicology of Shenzhen, Medical Key Laboratory of Guangdong Province, Medical Key Laboratory of Health Toxicology of Shenzhen, Shenzhen Center for Disease Control and Prevention, Shenzhen, China.
authors.forename: Jianhui
authors.initials: J
authors.lastname: Yuan
authors.affiliation: Key Laboratory of Modern Toxicology of Shenzhen, Medical Key Laboratory of Guangdong Province, Medical Key Laboratory of Health Toxicology of Shenzhen, Shenzhen Center for Disease Control and Prevention, Shenzhen, China College of Life Sciences, Shenzhen University, Shenzhen, China.
authors.forename: Xuling
authors.initials: X
authors.lastname: Li
authors.affiliation: Laboratory of Neurodegenerative Diseases, Department of Anatomy, The University of Hong Kong, Pokfulam, Hong Kong SAR, China.
authors.forename: Raymond Chuen-Chung
authors.initials: RC
authors.lastname: Chang
authors.affiliation: Department of Neurology, Shanghai Jiaotong University Affiliated the Sixth Hospital, Shanghai, China.
authors.forename: Zhongsen
authors.initials: Z
authors.lastname: Qu
authors.affiliation: Key Laboratory of Modern Toxicology of Shenzhen, Medical Key Laboratory of Guangdong Province, Medical Key Laboratory of Health Toxicology of Shenzhen, Shenzhen Center for Disease Control and Prevention, Shenzhen, China.
authors.forename: Xinfeng
authors.initials: X
authors.lastname: Huang
authors.affiliation: Key Laboratory of Modern Toxicology of Shenzhen, Medical Key Laboratory of Guangdong Province, Medical Key Laboratory of Health Toxicology of Shenzhen, Shenzhen Center for Disease Control and Prevention, Shenzhen, China.
authors.forename: Zhixiong
authors.initials: Z
authors.lastname: Zhuang
authors.affiliation: Key Laboratory of Modern Toxicology of Shenzhen, Medical Key Laboratory of Guangdong Province, Medical Key Laboratory of Health Toxicology of Shenzhen, Shenzhen Center for Disease Control and Prevention, Shenzhen, China.
authors.forename: Jianjun
authors.initials: J
authors.lastname: Liu
authors.affiliation: Key Laboratory of Modern Toxicology of Shenzhen, Medical Key Laboratory of Guangdong Province, Medical Key Laboratory of Health Toxicology of Shenzhen, Shenzhen Center for Disease Control and Prevention, Shenzhen, China.
authors.forename: Xifei
authors.initials: X
authors.lastname: Yang
mesh_terms: D000544:Alzheimer Disease / Q000378:metabolism* / Q000523:psychology; D016564:Amyloid beta-Protein Precursor / Q000235:genetics / Q000378:metabolism; D000818:Animals; D015153:Blotting, Western; D003071:Cognition; D019327:Copper Sulfate / Q000633:toxicity*; D004195:Disease Models, Animal; D006624:Hippocampus / Q000378:metabolism*; D006801:Humans; D013058:Mass Spectrometry; D018782:Maze Learning / Q000187:drug effects / Q000502:physiology; D008569:Memory Disorders / Q000139:chemically induced* / Q000378:metabolism*; D008822:Mice, Transgenic; D053764:Presenilin-1 / Q000235:genetics / Q000378:metabolism; D040901:Proteomics; D065852:Spatial Memory / Q000187:drug effects / Q000502:physiology; D016875:tau Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: C545487:APP protein, human; D016564:Amyloid beta-Protein Precursor; C054369:MAPT protein, human; C508853:PSEN1 protein, human; D053764:Presenilin-1; D016875:tau Proteins; D019327:Copper Sulfate
keywords: Alzheimer's disease; copper; memory impairment; two-dimensional fluorescence difference gel electrophoresis