Department
neurobiology
Document Type
Article
Abstract
Amyloid-β (Aβ) accumulation and aggregation are thought to contribute to the pathogenesis of Alzheimer's disease (AD). In AD, there is a selective decrease in the numbers of radioligand binding sites corresponding to the most abundant nicotinic acetylcholine receptor (nAChR) subtype, which contains human α4 and β2 subunits (hα4β2-nAChR). However, the relationships between these phenomena are uncertain, and effects of Aβ on hα4β2-nAChR function have not been investigated in detail. We first confirmed expression of hα4 and hβ2 subunits as messenger RNA in transfected, human SH-EP1 cells by reverse transcription-polymerase chain reaction and mRNA fluorescence in situ, hybridization analyses. Immunoprecipitation Western analyses confirmed α4 and β2 subunit protein expression and coassembly. Whole cell current recording demonstrated heterologous expression in SH-EP1-hα4β2 cells of functional hα4β2-nAChRs with characteristic responses to nicotinic agonists or antagonists. Nicotine-induced whole cell currents were suppressed by Aβ1-42 in a dose-dependent manner. Functional inhibition was selective for Aβ1-42compared with the functionally inactive, control peptide Aβ40-1. Aβ1-42-mediated inhibition of hα4β2-nAChR function was non-competitive, voltage-independent, and use-independent. Pre-loading of cells with guanyl-5′-yl thiophosphate failed to prevent Aβ1-42- induced inhibition, suggesting that down-regulation of hα4β2-nAChR function by Aβ1-42 is not mediated by nAChR intemalization. Sensitivity to Aβj_42 antagonism at 1 nM was evident for hα4β2-nAChRs, but not for heterologously expressed human α7-nAChRs, although both nAChR subtypes were functionally inhibited by 100 nM Aβ1-42, with the magnitude of functional block being higher for 100 nM Aβ1-42 acting on hα7-nAChRs. These findings suggest that hα4β2-nAChRs are sensitive and perhaps pathophysiologically relevant targets for Aβ neurotoxicity in AD.
Publication Date
9-3-2004
Publication Title
Journal of Biological Chemistry
ISSN
00219258
Volume
279
Issue
36
First Page
37842
Last Page
37851
Digital Object Identifier (DOI)
10.1074/jbc.M400335200
Recommended Citation
Wu, Jie; Kuo, Yen Ping; George, Andrew A.; Xu, Lin; Hu, Jun; and Lukas, Ronald J., "β-Amyloid Directly Inhibits Human α4β3-Nicotinic Acetylcholine Receptors Heterologously Expressed In Human Sh-Ep1 Cells" (2004). Translational Neuroscience. 75.
https://scholar.barrowneuro.org/neurobiology/75