Chemico-Biological Interactions 187 (2010) 120–123 Contents lists available at ScienceDirect Chemico-Biological Interactions journal homepage: www.elsevier.com/locate/chembioint Differential gene expression profiling on the muscle of acetylcholinesterase knockout mice: A preliminary analysis Huang-Quan Lin a , Roy Choi c , Kam-Leung Chan b , Denis Ip a , Karl Wah-keung Tsim c , David Chi-cheong Wan a,∗ a School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, SAR, China b School of Chinese Medicine, Chinese University of Hong Kong, Hong Kong, SAR, China c Department of Biology, Hong Kong University of Science and Technology, Hong Kong, SAR, China article info Article history: Available online 8 April 2010 Keywords: AChE deficient mice Gene profiling Microarray analysis abstract Acetylcholinesterase (AChE) (EC. 3.1.1.7) is the acetylcholine-hydrolyzing enzyme that plays an essential role on cholinergic neurotransmission at the synapses of the brain and at the neuromuscular junctions. In order to gain insight into the molecular mechanisms of neuromuscular dysfunction associated with AChE deficiency, we have compared the RNA expression profiles of the muscles of AChE knockout mice with those of the wild-type siblings. Total RNA from the leg muscle of the mice of the wild-type and the AChE nullizygous mice were subjected to microarray analyses with Affymetrix GeneChip ® Mouse Gene 1.0 ST Array. The pair-wise comparison of gene expression levels of the 28,853 mRNA transcripts showed that 303 genes were either up- or down-regulated by more than 2.0 folds in the AChE knockout mice. The interaction study of these differentially regulated genes indicated that some of these genes are clustered in biological functions that are related to lipid metabolism and the skeletal–muscular functions. © 2010 Elsevier Ireland Ltd. All rights reserved. 1. Introduction Acetylcholinesterase (AChE) (EC. 3.1.1.7) is the acetylcholine- hydrolyzing enzyme that plays an essential role on cholinergic neuromuscular transmission in the brain and at the neuromuscular junctions (for review see [1]). Abnormal expression and localization of AChE have been implicated in the etiology of neurodegenera- tive diseases such as Alzheimer’s disease [2]. The AChE knockout (KO) mice provide a valuable animal model to study the role of this enzyme in muscle function [3,4]. Previous work demonstrated that the AChE KO mice were alive but exhibited body tremor and impaired body movement, indicating a severe muscular dysfunc- tion [5]. In order to gain insight into the molecular mechanisms of neuromuscular dysfunction due to AChE deficiency, we have compared the RNA expression profiles of the muscle of the AChE knockout mice with those of the muscle of the wild-type siblings. ∗ Corresponding author. School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Rm178 Science Center, Shatin, N.T., Hong Kong, SAR, China. Tel.: +852 26096252; fax: +852 26037246. E-mail addresses: chicheongwan@cuhk.edu.hk, b482770@mailserv.cuhk.edu.hk (D.C.-c. Wan). 2. Materials and methods 2.1. AChE knockout animals and microarray gene chips AChE knockout mice (129/Sv) were kindly donated by Dr. Oksana Lockridge of University of Nebraska (NE, USA) [6]. Both the homozygous and the nullizygous AChE mice were obtained by mating with the heterozygote AChE mice in-house at the Ani- mal House of the Chinese University of Hong Kong. The mice were kept under controlled temperature and humidity condi- tions, with a 12/12 h day and night cycle. The GeneChip ® Mouse Gene 1.0 ST Array was purchased from Affymetrix (Affymetrix, USA). 2.2. Sample preparation Mice were sacrificed according to animal ethics regulations. Tissues from three animals were collected for each group (homozy- gous wild-type and AChE nullizygous mice). Tissues dissected from leg muscles were extracted with trizol reagent according to the manufacturer’s protocol (Invitrogen). An aliquot (300 ng) of RNA was used for the preparation of targets for GeneChip Gene 1.0 ST arrays according to the GeneChip Whole Transcript (WT) Sense Target Labeling Assay manual. 0009-2797/$ – see front matter © 2010 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.cbi.2010.03.054