title: Inhibiting gene expression of alpha3 nicotinic receptor in SH-SY5Y cells with the effects on APP metabolism and antioxidation in Alzheimer's disease.
abstract: In order to examine the effects of alpha3 nicotinic acetylcholine receptor (nAChR) in connection with the pathogenesis of Alzheimer's disease (AD), neuroblastoma (SH-SY5Y) cells were transfected with small interference RNAs (siRNAs) that target specifically towards alpha3 nAChR. The expressions of alpha3 nAChR mRNA and protein were measured by real-time PCR and Western blotting, respectively. The levels of the alpha-form of secreted amyloid precursor protein (alphaAPPs) and total-APP were determined by Western blotting. SH-SY5Y cells transfected with siRNA were then treated with 1muM beta-amyloid peptide (Abeta)(1-42), following which the levels of lipid peroxidation, the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), and the reduction rate of MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] were characterized by utilizing spectrophotometric procedures. As compared to controls, SH-SY5Y cells transfected with siRNA expressed the decreases in the levels of alpha3 nAChR mRNA and protein by 98% and 66% lower levels, respectively; exhibited reduced level of the alphaAPPs; and demonstrated enhanced lipid peroxidation, decreased rate of MTT reduction, and declined activities of SOD and GSH-Px. Inhibited gene expression of the alpha3 nAChR enhanced the toxicity exerted by Abeta. These results indicate that alpha3 nAChR may improve cleavage of APP by alpha-secretase, enhance antioxidation and inhibit the toxicity of Abeta, suggesting that the receptor might play an important role in AD.
authors.affiliation: Department of Pathology and Molecular Biology, Guiyang Medical University, Guiyang 550004, Guizhou, PR China.
authors.forename: Zhi
authors.initials: Z
authors.lastname: Tang
authors.forename: Yu
authors.initials: Y
authors.lastname: An
authors.forename: Xiao-Lan
authors.initials: XL
authors.lastname: Qi
authors.forename: Yan
authors.initials: Y
authors.lastname: Xiao
authors.forename: Ke-Ren
authors.initials: KR
authors.lastname: Shan
authors.forename: Zhi-Zhong
authors.initials: ZZ
authors.lastname: Guan
mesh_terms: D000544:Alzheimer Disease / Q000378:metabolism*; D016229:Amyloid beta-Peptides / Q000378:metabolism* / Q000494:pharmacology; D045744:Cell Line, Tumor; D005979:Glutathione Peroxidase / Q000378:metabolism; D006801:Humans; D015227:Lipid Peroxidation; D018384:Oxidative Stress; D010088:Oxidoreductases / Q000378:metabolism; D010446:Peptide Fragments / Q000494:pharmacology; D011498:Protein Precursors / Q000096:biosynthesis; D034622:RNA Interference; D012333:RNA, Messenger / Q000096:biosynthesis; D034741:RNA, Small Interfering / Q000235:genetics; D011978:Receptors, Nicotinic / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D016229:Amyloid beta-Peptides; D005979:Glutathione Peroxidase; D010088:Oxidoreductases; D010446:Peptide Fragments; D011498:Protein Precursors; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D011978:Receptors, Nicotinic; C075222:amyloid beta-protein (1-42); C121849:superoxide reductase