title: Preventing expression of the nicotinic receptor subunit α7 in SH-SY5Y cells with interference RNA indicates that this receptor may protect against the neurotoxicity of Aβ.
abstract: The present aim was to characterize the influence of the α7 nicotinic acetylcholine receptor (nAChR) on BACE, the enzyme that cleaves the amyloid precursor protein (APP) at the β-site, as well as on the oxidative stress induced by amyloid-β peptide (Aβ). To this end, human neuroblastoma SH-SY5Y cells were transfected with siRNAs targeting the α7 nAChR subunit and/or exposed to Aβ1-42. For α7 nAChR, BACE1 (cleaving at the β-site of APP) and BACE2 (cleaving within the Aβ domain), α-secretase (ADAM10), and the two components of γ-secretase, PS and NCT, the mRNA and protein levels were determined by real-time PCR and Western blotting, respectively. The level of Aβ1-42 in the cell culture medium was determined by an ELISA procedure. The extent of lipid peroxidation and activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) were assayed spectrophotometrically. In the transfected SH-SY5Y cells, expression of α7 nAChR was reduced; the level of BACE1 increased and that of BACE2 decreased; the amount of ADAM10 lowered; and the level of PS raised. Moreover, the level of Aβ1-42 in the culture medium was elevated. Treatment of non-transfected cells with Aβ elevated the level of malondialdehyde (MDA) and lowered the activities of SOD and GSH-Px and these changes were potentiated by inhibiting expression of α7 nAChR. These results indicate that α7 nAChR plays a significant role in amyloidogenic metabolism of APP and the oxidative stress evoked by Aβ, suggesting that this receptor might help protect against the neurotoxicity of Aβ.
authors: Department of Molecular Biology, Guiyang Medical University, Guiyang 550004, People's Republic of China.
authors: Xiao-Lan
authors: XL
authors: Qi
authors: Kai
authors: K
authors: Ou-Yang
authors: Jia-Mou
authors: JM
authors: Ren
authors: Chang-Xue
authors: CX
authors: Wu
authors: Yan
authors: Y
authors: Xiao
authors: Yi
authors: Y
authors: Li
authors: Zhi-Zhong
authors: ZZ
authors: Guan
mesh_terms: D016229:Amyloid beta-Peptides / Q000235:genetics* / Q000502:physiology; D001483:Base Sequence; D045744:Cell Line, Tumor; D017931:DNA Primers; D006801:Humans; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000235:genetics*; D060888:Real-Time Polymerase Chain Reaction; D011978:Receptors, Nicotinic / Q000378:metabolism*; D064569:alpha7 Nicotinic Acetylcholine Receptor
chemical_list: D016229:Amyloid beta-Peptides; C579167:Chrna7 protein, human; D017931:DNA Primers; D034741:RNA, Small Interfering; D011978:Receptors, Nicotinic; D064569:alpha7 Nicotinic Acetylcholine Receptor