ABSTRACT
Pathological amino-acid substitutions in the amyloid precursor protein (APP) and chemical γ-secretase modulators affect the processing of APP by the γ-secretase complex and the production of the amyloid-beta peptide Aß42, the accumulation of which is considered causative of Alzheimer's disease. Here we demonstrate that mutations in the transmembrane domain of APP causing aggressive early-onset familial Alzheimer's disease affect both γ- and ε-cleavage sites, by raising the Aß42/40 ratio and inhibiting the production of AICD50-99, one of the two physiological APP intracellular domains (ICDs). This is in sharp contrast to γ-secretase modulators, which shift Aß42 production towards the shorter Aß38, but unequivocally spare the ε-site and APP- and Notch-ICDs production. Molecular simulations suggest that familial Alzheimer's disease mutations modulate the flexibility of the APP transmembrane domain and the presentation of its γ-site, modifying at the same time, the solvation of the ε-site.
Subject(s)
Alzheimer Disease/genetics , Amyloid Precursor Protein Secretases/metabolism , Amyloid beta-Protein Precursor/chemistry , Amyloid beta-Protein Precursor/genetics , Mutation/genetics , Amino Acid Sequence , Amyloid beta-Protein Precursor/metabolism , Humans , Imidazoles/chemistry , Imidazoles/pharmacology , Magnetic Resonance Spectroscopy , Mass Spectrometry , Models, Molecular , Molecular Sequence Data , Mutant Proteins/chemistry , Mutant Proteins/metabolism , Piperidines/chemistry , Piperidines/pharmacology , Protein Structure, Tertiary , Proteolysis/drug effects , Receptors, Notch/metabolismABSTRACT
The RNAimmuno database was created to provide easy access to information regarding the nonspecific effects generated in cells by RNA interference triggers and microRNA regulators. Various RNAi and microRNA reagents, which differ in length and structure, often cause non-sequence-specific immune responses, in addition to triggering the intended sequence-specific effects. The activation of the cellular sensors of foreign RNA or DNA may lead to the induction of type I interferon and proinflammatory cytokine release. Subsequent changes in the cellular transcriptome and proteome may result in adverse effects, including cell death during therapeutic treatments or the misinterpretation of experimental results in research applications. The manually curated RNAimmuno database gathers the majority of the published data regarding the immunological side effects that are caused in investigated cell lines, tissues, and model organisms by different reagents. The database is accessible at http://rnaimmuno.ibch.poznan.pl and may be helpful in the further application and development of RNAi- and microRNA-based technologies.