title: Down-regulation of muscarinic acetylcholine receptor M2 adversely affects the expression of Alzheimer's disease-relevant genes and proteins.
abstract: Beta-amyloid peptides play a major role in the pathogenesis of Alzheimer's disease (AD). Therefore, preventing beta-amyloid formation by inhibition of the beta site amyloid precursor protein-cleaving enzyme (BACE) 1 is considered as a potential strategy to treat AD. Cholinergic mechanisms have been shown to control amyloid precursor protein processing and the number of muscarinic M2-acetylcholine receptors is decreased in brain regions of patients with AD enriched with senile plaques. Therefore, the present study investigates the effect of this M2 muscarinic receptor down-regulation by siRNA on total gene expression and on regulation of BACE1 in particular in SK-SH-SY5Y cells. This model system was used for microarray analysis after carbachol stimulation of siRNA-treated cells compared with carbachol stimulated, non-siRNA-treated cells. The same model system was used to elucidate changes at the protein level by using two-dimensional gels followed by Matrix Assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF) analysis. Taken together, the results indicate that the M2 acetylcholine receptor down-regulation in brains of patients with AD has important effects on the expression of several genes and proteins with major functions in the pathology of AD. This includes beta-secretase BACE1 as well as several modulators of the tau protein and other AD-relevant genes and proteins. Moreover, most of these genes and proteins are adversely affected against the background of AD.
authors.affiliation: Paul Flechsig Institute for Brain Research, Department of Neurochemistry, University of Leipzig, Leipzig, Germany.
authors.forename: Thole
authors.initials: T
authors.lastname: Zuchner
authors.forename: Reinhard
authors.initials: R
authors.lastname: Schliebs
authors.forename: J Regino
authors.initials: JR
authors.lastname: Perez-Polo
mesh_terms: D000544:Alzheimer Disease / Q000235:genetics* / Q000378:metabolism*; D053829:Amyloid Precursor Protein Secretases; D016282:Aspartic Acid Endopeptidases / Q000378:metabolism*; D045744:Cell Line, Tumor; D015536:Down-Regulation; D010450:Endopeptidases; D015870:Gene Expression; D020869:Gene Expression Profiling; D006801:Humans; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D020411:Oligonucleotide Array Sequence Analysis; D034741:RNA, Small Interfering / Q000494:pharmacology; D043585:Receptor, Muscarinic M2 / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D009419:Nerve Tissue Proteins; D034741:RNA, Small Interfering; D043585:Receptor, Muscarinic M2; D053829:Amyloid Precursor Protein Secretases; D010450:Endopeptidases; D016282:Aspartic Acid Endopeptidases; C509280:BACE1 protein, human