Biochemical and Biophysical Research Communications, Vol.515, No.3, 462-467, 2019
An App knock-in mouse inducing the formation of a toxic conformer of A beta as a model for evaluating only oligomer-induced cognitive decline in Alzheimer's disease
Irie and colleagues identified a "toxic conformer", which possesses a turn structure at positions 22-23, among various conformations of A beta and have been reporting its potent oligomeric capacity and neurotoxicity. This toxic conformer was detected in the brains of AD patients and AD model mice (Tg2576 line), and passive immunization targeting this conformer ameliorated the cognitive dysfunction in an AD model. In this study, we developed a novel AD mouse model (App(NL-P-F/NL-P-F)) with Swedish mutation (NL), Iberian mutation (F), and mutation (P) overproducing E22P-A beta. a mimic of the toxic conformer, utilizing the knock-in technique that well recapitulates the A beta pathology of AD patients in mice and avoids the artificial phenotype observed in transgenic-type model mice. We confirmed that App(NL-P-F/NL-P-F) mice produce A beta by ELISA and accumulate senile plaques by immunohistochemistry at eight months of age. In WB, we observed a potential trimer band and high molecular-weight oligomer bands without a monomeric band in the TBS-soluble fraction of App(NL-P-F/NL-P-F) mice at six months of age. In the novel object recognition test, cognitive impairment was observed at six months of age in these mice. These findings suggest that the toxic conformer of A beta induces cognitive dysfunction mediated by its oligomer formation in this mouse brain. App(NL-P-F/NL-P-F) mice may be a useful model for evaluating A beta oligomer-induced cognitive impairment in AD and will aid in exploring therapeutic targets for AD pathology. (C) 2019 Elsevier Inc. All rights reserved.