Experimental animals
All of the procedures in this study were carried out in accordance with the British Home Office regulations under the Animal Scientific Procedure Act 1986, under the project licence PPL: P1ADA633A held by the principal investigator, Dr. Afia Ali. All procedures were approved by both internal and external UCL ethics committees, and in accordance with the ARRIVE guide-lines for reporting experiments involving animals (McGrath et al., 2010). A total of ~100 animals (disease model and wild-type) were used in this study. The animals hadad-libitum access to food and water and were reared in cages of maximum 5 inhabitants, with a day: night cycle of 12 hours: 12 hours.
The knock-in APPNL-F/NL-F AD mouse model was used for experiments (Saito et al., 2014), which consists of the introduction of two familial AD (FAD) mutations: KM670/671NL and I716F. The former, identified as the Swedish mutation, increases β-site cleavage of APP to produce elevated amounts of both Aβ40and Aβ42, whereas the latter, known as the Beyreuther/Iberian mutation, promotes γ-site cleavage at C-terminal position 42, thereby increasing the Aβ42/Aβ40 ratio in favour of the more hydrophobic Aβ42 (Saito et al., 2014). Both features are key to the integrity of the disease phenotype. The knock-in line was crossed with C57BL/6 mice, and maleAPPNL-F/NL-F and age-matched wild-type (C57BL/6) mice from the same breeding were used as control at 9 - 18 months.
Animals were genotyped via standard polymerase chain reaction using the following four primers: 5′-ATCTCGGAAGTGAAGATG-3′, 5′-TGTAGATGAGAACTTAAC-3′, 5′-ATCTCGGAAGTGAATCTA-3′, and 5′-CGTATAATGTATGCTATACGAAG-3′ as previously described (Saito et al., 2014). Further details of rationale for selecting this mouse model can be found in Petrache et al., (2019).